Effects of Lithium Ions on Dye-Sensitized ZnO Aggregate Solar Cells

The Effects of Climate Change on Biodiversity Climate change is one of the most pressing issues of our time, and it is having a significant impact on biodiversity. The Earth's climate is changing rapidly, and this is affecting the natural habitats of many species around the world. The effects of climate change on biodiversity are complex and far-reaching, and they are having a profound impact on the natural world. In this essay, I will explore the effects of climate change on biodiversity from multiple perspectives.One of the most significant effects of climate change on biodiversity is the loss of habitats. As the Earth's temperature rises, many species are losing their natural habitats. This is because the habitats they live in are becoming uninhabitable due to the changing climate. For example, coral reefs are dying due to rising ocean temperatures, and many species that depend on these reefs for their survival are also at risk. Similarly, many species of plants and animals that live in the Arctic are at risk of losing their habitats as the ice melts.Another effect of climate change on biodiversity is the loss of species. As habitats disappear, many species are unable to adapt to the changing climate. This can lead to the extinction of species, which can have a significant impact on the ecosystem. For example, if a predator species becomes extinct, it can lead to an overpopulation of its prey species, which can have a cascading effect on the ecosystem. Similarly, if a plant species becomes extinct, it can affect the animals that depend on that plant for food or shelter.Climate change is also affecting the timing of natural events, such as migration and breeding. Many species rely on specific environmental cues to time their migration or breeding. For example, birds rely on changes in day length to time their migration, while many plants rely on temperature and rainfall to time their flowering. As the climate changes, these environmental cues are becoming less predictable, which can lead to mismatches between the timing of natural events and the availability of resources. This can have a significant impact on the survival of many species.In addition to these direct effects, climate change is also affecting the interactions between species. For example, as the temperature rises, some species are expanding theirranges into new areas. This can lead to competition with native species for resources, which can have a significant impact on the ecosystem. Similarly, as the climate changes, some species are becoming more susceptible to diseases or parasites, which can have a cascading effect on the ecosystem.Finally, climate change is also affecting human societies. Many communities around the world rely on natural resources for their livelihoods, such as fishing or agriculture. As the climate changes, these resources are becoming less predictable, which can have a significant impact on these communities. In addition, climate change is also leading to more extreme weather events, such as floods and droughts, which can have a significant impact on human societies.In conclusion, the effects of climate change on biodiversity are complex and far-reaching. They are having a profound impact on the natural world, affecting habitats, species, natural events, interactions between species, and human societies. It is essential that we take action to address climate change and protect biodiversity for future generations. This will require a concerted effort from governments, businesses, and individuals around the world. Only by working together can we hope to mitigate the effects of climate change and protect the natural world.。

The Impact of Deforestation onBiodiversity LossDeforestation is a critical issue that has a significant impact onbiodiversity loss. The destruction of forests around the world has led to adecline in the number of species that inhabit these areas, ultimately affectingthe delicate balance of ecosystems. This loss of biodiversity can have far-reaching consequences for the environment, as each species plays a unique role in maintaining the health and stability of their respective habitats. One of the most immediate effects of deforestation on biodiversity loss is the destruction of natural habitats. Forests are home to a vast array of plant and animal species, many of which are endemic to these areas. When forests are cleared foragricultural or industrial purposes, these species lose their homes and are often unable to find suitable alternatives. This can lead to a decline in population numbers, and in some cases, even extinction. In addition to habitat destruction, deforestation can also disrupt the intricate relationships between species within an ecosystem. Many species rely on each other for food, shelter, and other resources, forming complex food webs and symbiotic relationships. When key species are lost due to deforestation, it can have a ripple effect throughout the entire ecosystem, leading to further declines in biodiversity. Furthermore,deforestation can also have indirect effects on biodiversity loss through climate change. Forests play a crucial role in regulating the Earth's climate by absorbing carbon dioxide from the atmosphere and releasing oxygen through photosynthesis. When forests are cleared, this natural carbon sink is disrupted, leading to an increase in greenhouse gas emissions and global warming. This can have devastating effects on biodiversity, as many species are unable to adapt to rapid changes in temperature and weather patterns. The loss of biodiversity due to deforestationis not only a threat to the environment but also to human well-being. Many communities around the world rely on forests for their livelihoods, including food, medicine, and shelter. When biodiversity is lost, these resources become scarce, leading to increased poverty and food insecurity. Additionally, many indigenous cultures have deep spiritual and cultural connections to the forests and thespecies that inhabit them. The loss of these sacred landscapes can have profound emotional and psychological impacts on these communities. In order to address the issue of deforestation and biodiversity loss, it is crucial for governments, organizations, and individuals to take action. One possible solution is to implement sustainable land management practices that prioritize the conservation and restoration of forests. This can include reforestation efforts, protected area designation, and sustainable logging practices that minimize the impact on biodiversity. Additionally, raising awareness about the importance of forests and biodiversity is essential in garnering support for conservation efforts. Overall, the impact of deforestation on biodiversity loss is a complex and multifaceted issue that requires immediate attention and action. By recognizing the interconnectedness of all species and ecosystems, we can work towards preserving the rich diversity of life on Earth for future generations to enjoy. It is crucial that we prioritize the protection of forests and the species that call them home, as they play a vital role in maintaining the health and balance of our planet.。

英语考研2024真题答案### English Postgraduate Entrance Examination 2024: Sample Answers#### Part I: Reading Comprehension (40 points)Passage 1: The Impact of Technology on EducationThe article discusses the profound influence of technology on modern education. It highlights how digital tools have revolutionized teaching methods, making learning more interactive and personalized. The integration of AI in classrooms has allowed for the creation of adaptive learning environments that cater to the needs of individual students. Moreover, the use of online platforms has expanded access to education, breaking down geographical barriers and providing opportunities for lifelong learning.Questions:1. What is the primary focus of the article?- The primary focus is the impact of technology on the field of education.2. How has AI been utilized in classrooms?- AI has been used to create adaptive learning environments tailored to individual students' needs.3. What benefits does online education offer?- Online education offers expanded access, overcoming geographical limitations and promoting lifelong learningopportunities.Passage 2: Climate Change and Its Effects on BiodiversityThis passage examines the alarming effects of climate change on global biodiversity. It underscores the rapid loss of species due to habitat destruction and altered ecosystems. The text also discusses the potential for climate change to exacerbate existing threats to biodiversity, such as overfishing and deforestation. The urgency for global action to mitigate these effects is emphasized, with the need for sustainable practices and conservation efforts.Questions:1. What is the main concern of the passage?- The main concern is the impact of climate change on biodiversity and the rapid loss of species.2. Which factors contribute to the threats to biodiversity mentioned in the passage?- Factors include habitat destruction, altered ecosystems, overfishing, and deforestation.3. What solutions does the passage suggest?- The passage suggests global action, sustainable practices, and conservation efforts as solutions.#### Part II: Cloze Test (20 points)In the cloze test section, candidates are required to fill in the blanks with the most appropriate word from the given options to ensure the passage makes sense both contextually and grammatically. This section tests the ability tounderstand context and the correct usage of vocabulary.#### Part III: Translation (20 points)English to Chinese:Translate the following sentence into Chinese, ensuring accuracy and fluency.- "The rapid development of urbanization has led to a series of environmental issues."Chinese to English:Translate the following sentence into English, maintaining the original meaning and ensuring natural language flow.- "随着科技的不断进步，我们的生活变得越来越便利。

介绍冷凝现象英语作文English Response:Understanding Condensation.Condensation is a fascinating phenomenon that occurs when a gas transforms into a liquid. It's a common sight in our daily lives, whether it's seeing droplets form on a cold drink or watching mist appear on a mirror after a hot shower.What Causes Condensation?Condensation happens due to a decrease in temperature. When warm, moisture-laden air comes into contact with a colder surface, it loses heat energy. As a result, the air cools down, causing the water vapor within it to lose energy as well. This loss of energy leads to the water vapor changing its state from gas to liquid, forming droplets.Real-Life Examples.Imagine you're sipping a refreshing drink on a warm summer day. The cold surface of the glass cools down the surrounding air. As a result, the water vapor in the air condenses on the outside of the glass, forming dropletsthat trickle down its surface. This is a classic example of condensation in action.Another example is when you take a hot shower. The steam generated from the hot water fills the bathroom with moisture-laden air. When this warm air comes into contact with the cooler surface of a mirror, condensation occurs, fogging up the mirror's surface.Importance of Condensation.Condensation plays a crucial role in various natural processes and human activities. In the atmosphere, condensation is responsible for the formation of clouds and precipitation, which are essential for the water cycle andsustaining life on Earth. In industrial settings, condensation is utilized in processes like distillation and refrigeration.Preventing Condensation.While condensation is a natural occurrence, excessive condensation can lead to issues such as mold growth and water damage. To prevent these problems, proper ventilation and insulation are key. By controlling indoor humidity levels and ensuring adequate airflow, you can minimize the risk of condensation forming on surfaces within your home or workplace.Conclusion.In summary, condensation is a fascinating natural phenomenon driven by temperature differences. Whether it's observing droplets form on a cold surface or witnessing clouds form in the sky, condensation surrounds us in various forms. Understanding the causes and effects of condensation not only deepens our appreciation for theworld around us but also helps us manage its impact on our daily lives.---。

The Cambrian ExplosionThe geologic timescale is marked by significant geologic and biological events, including the origin of Earth about 4.6 billion years ago, the origin of life about 3.5 billion years ago, the origin of eukaryotic life-forms (living things that have cells with true nuclei) about 1.5 billion years ago, and the origin of animals about 0.6 billion years ago. The last event marks the beginning of the Cambrian period. Animals originated relatively late in the history of Earth—in only the last 10 percent of Earth’s history. During a geologically brief 100-million-year period, all modern animal groups (along with other animals that are now extinct) evolved. This rapid origin and diversification of animals is often referred to as “the Cambrian explosion.”Scientists have asked important questions about this explosion for more than a century. Why did it occur so late in the history of Earth? The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself. Why does the fossil record not document the series of evolutionary changes during the evolution of animals? Why did animal life evolve so quickly? Paleontologists continue to search the fossil record for answers to these questions.One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft bodied and simply did not fossilize. Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. Conditions that promote fossilization of soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. In fact, fossil beds containing soft-bodied animals have been known for many years.The Ediacara fossil formation, which contains the oldest known animal fossils, consists exclusively of soft-bodied forms. Although named after a site in Australia, the Ediacara formation is worldwide in distribution and dates to Precambrian times. This 700-million-year-old formation gives few clues to the origins of modern animals, however, because paleontologists believe it represents an evolutionary experiment that failed. It contains no ancestors of modern animal groups.A slightly younger fossil formation containing animal remains is the Tommotian formation, named after a locale in Russia. It dates to the very early Cambrian period, and it also contains only soft-bodied forms. At one time, the animals present in these fossil beds were assigned to various modern animal groups, but most paleontologists now agree that all Tommotian fossils represent unique body forms that arose in the early Cambrian period and disappeared before the end of the period, leaving no descendants in modern animal groups.A third fossil formation containing both soft-bodied and hard-bodied animals provides evidence of the result of the Cambrian explosion. This fossil formation, called the Burgess Shale, is in Yoho National Park in the Canadian Rocky Mountains of British Columbia. Shortly after the Cambrian explosion, mud slides rapidly buried thousands of marine animals under conditions that favored fossilization. These fossil beds provideevidence of about 32 modern animal groups, plus about 20 other animal body forms that are so different from any modern animals that they cannot be assigned to any one of the modern groups. These unassignable animals include a large swimming predator called Anomalocaris and a soft-bodied animal called Wiwaxia, which ate detritus or algae. The Burgess Shale formation also has fossils of many extinct representatives of modern animal groups. For example, a well-known Burgess Shale animal called Sidneyia is a representative of a previously unknown group of arthropods (a category of animals that includes insects, spiders, mites, and crabs).Fossil formations like the Burgess Shale show that evolution cannot always be thought of as a slow progression. The Cambrian explosion involved rapid evolutionary diversification, followed by the extinction of many unique animals. Why was this evolution so rapid? No one really knows. Many zoologists believe that it was because so many ecological niches were available with virtually no competition from existing species. Will zoologists ever know the evolutionary sequences in the Cambrian explosion? Perhaps another ancient fossil bed of soft-bodied animals from 600-million-year-old seas is awaiting discovery.the origin of Earth about 4.6 billion years ago, the origin of life about 3.5 billion years ago, the origin of eukaryotic life-forms (living things that have cells with true nuclei) about 1.5 billion years ago, and the origin of animals about 0.6 billion years ago. The last event marks the beginning of the Cambrian period. Animalslate in the history of Earth—in only the last 10 percent of Earth’s history. During aof animals is often referred to as “the Cambrian explosion.”passage is closest in meaning to○ numerous○ important○ unexplained○ sudden○ surprisingly○ collectively○ comparatively○ characteristicallythe passage is closest in meaning to○ emergence of many varieties○ steady decline in number○ gradual increase in body size○ sudden disappearanceWhy did it occur so late in the history of Earth? The origin of multicellular forms of life seems a relatively simple step compared to the origin of life itself. Why does the fossil record not document the series of evolutionary changes during the evolution of animals? Why did animal life evolve so quickly? Paleontologists continue to search the fossil record for answers to these questions.○ occurred 0.6 billion years ago,late in Earth’s history○ was characterized by the unusually fast evolution of many new life-forms○ was characterized by widespread animal extinction○ was characterized by violent volcanic eruptions5. According to Paragraph2, which of the following is NOT a question that paleontologists asked about the Cambrian explosion?○ Why was the origin of life a simple step in Earth’s history?○ Why did it take so long for multicellular organisms to develop?○ Why did animal life evolve so rapidly?○ Why do es the fossil record lack evidence of animal evolution during that time?6. Which of the following best describes the relationship between paragraph 2 and paragraph 3?○ Paragraph 2 puts forward several scientific claims, one of which is rejected in p aragraph 3.○ Paragraph 2 poses several questions, and paragraph 3 offers a possible answer to one of them.○ Paragraph 2 presents outdated traditional views, while paragraph 3 presents the current scientific conclusions.○ Paragraph 2 introduces a general ization that is illustrated by specific examples in paragraph 3.Paragraph 3: One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft-bodied and simply did not fossilize. Fossilization of soft-bodied animalsof soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. In fact, fossil beds containing soft-bodied animals have been known for many years.○ complicate○ prevent○ encourage○ affectParagraph 4: The Ediacara fossil formation, which contains the oldest known animal fossils, consists exclusively of soft-bodied forms. Although named after a site in Australia, the Ediacara formation is worldwide in distribution and dates to Precambrian times. This 700-million-year-old formation gives few clues to the origins of modern animals, however, because paleontologists believe it represents an evolutionary experiment that failed. It contains no ancestors of modern animal groups.8. Which of the following is NOT mentioned in paragraph 4 as being true of the Ediacara formation?○ It contains fossils that date back to the Precambrian period.○ It contains only soft-bodied animal fossils.○ It is located on a single site in Australia.○ It does not contain any fossils of the ancestors of modern an imals.Paragraph 5: A slightly younger fossil formation containing animal remains is the Tommotian formation,the passage? Incorrect choices change the meaning in important ways or leave out essential information.○ The animals found in the Tommotian fossil bed were once thought to belong to a variety of modern animal groups, but now they are thought to have descended from a single group.○ Animals in the Tommotian fossil beds were initially assigned to modern an imal groups but are now thought to belong to groups that emerged and died out during the Cambrian period.○ Though at first they thought otherwise, paleontologists now agree that the animals in the Tommotian have body forms from which modern animals have descended.○ It is unclear whether the Tommotian fossils from the early Cambrian period represent unique body forms or whether they should be assigned to various modern animal groups.Paragraph 6: A third fossil formation containing both soft-bodied and hard-bodied animals provides evidence of the result of the Cambrian explosion. This fossil formation, called the Burgess Shale, is in Yoho National Park in the Canadian Rocky Mountains of British Columbia. Shortly after the Cambrian explosion, mud slides rapidly buried thousands of marine animals under conditions that favored fossilization. These fossil beds provide evidence of about 32 modern animal groups, plus about 20 other animal body forms that are so different from any modern animals that they cannot be assigned to any one of the modern groups. Theseate detritus or algae. The Burgess Shale formation also has fossils of many extinctis a representative of a previously unknown group of arthropods (a category of animals that includes insects,spiders, mites, and crabs).10. Why does○ To contrast predators with animals that eat plants such as algae○ To question the effects of rapid mud slides on fossilization○ To suggest that much is still unknown about animals found in the Burgess Shale○ To provide examples of fossils that cannot be assigned to a modern animal group○ a relative of Anomalocaris and Wiwaxia○ a previously unknown Burgess Shale animal○ an extinct member of a currently existing category of animals○ an animal that cannot be assigned to any modern animal groupParagraph 7: Fossil formations like the Burgess Shale show that evolution cannot always be thought of as a slow progression. The Cambrian explosion involved rapid evolutionary diversification, followed by the extinction of many unique animals. Why was this evolution so rapid? No one really knows. Many zoologists believe that it was because so many ecological niches were available with virtually no competition from existing species. Will zoologists ever know the evolutionary sequences in the Cambrian explosion? Perhaps another ancient fossil bed of soft-bodied animals from 600-million-year-old seas is awaiting discovery.12. What can be inferred from paragraph 7 about why the Cambrian explosion is so unusual?○ It generated new ecological niches through the extinction of many unique animals.○ It was a period of rapid evolution, and evolution is often thought of as a slow process.○ It is a period whose evolutionary sequences are clearly marked.○ It generated a very large number of ancient fossil beds containing soft-bodied animals.Paragraph 3: One interpretation regarding the absence of fossils during this important 100-million-year period is t hat early animals were soft bodied and simply did not fossilize. ■Fossilization of soft-bodied animals is less likely than fossilization of hard-bodied animals, but it does occur. ■Conditions that promote fossilization of soft-bodied animals include very rapid covering by sediments that create an environment that discourages decomposition. ■In fact, fossil beds containing soft-bodied animals have been known for many years. ■13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.It is relatively rare because the fossilization of soft-bodied animals requires a special environment.Where could the sentence best fit?14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.The term “Cambrian explosion” refers to the geologically brief period during which all modern animal groups evolved.●●●Answer Choices○Little is known about the stages of evolution during the Cambrian period, in part because early animals were soft bodied and could fossilize only under particular conditions.○While animal fossils from before the Cambrian explosion have no modern descendants, many animals that evolved during the Cambrian explosion can be assigned to modern groups.○The Cambrian period is significant because it marks the emergence of eukaryotic life-forms—organisms that have cells with true nuclei.○The Ediacara fossil formation provides the most information about the Cambrian explosion, while the earlier, Tommotian and Burgess Shale formations give clues about Precambrian evolution.○Zoologists are awaiting the discovery of a 600-million-year-old fossil formation in order to be able to form a theory of how animal evolution progressed.○Although the reasons for the rapid evolution of animals during the Cambrian period are not known, one proposed explanation is an abundance of niches with a lack of competitors.参考答案：1. ○22. ○33. ○14. ○25. ○16. ○27. ○38. ○39. ○210. ○411. ○312. ○213. ○214. Little is known about the…While animal fossils…Although the reasons for the…。

物质颗粒大小在水中的溶解快慢实验步骤-回复问题：物质颗粒大小在水中的溶解快慢实验步骤引言：物质的溶解是化学实验中一个重要的研究内容。

不同物质的颗粒大小对其在水中的溶解速度会有显著的影响。

本文将介绍一种简单实用的实验步骤，以探究物质颗粒大小对其在水中溶解速度的影响。

一、准备材料和设备1. 目标物质：选择两种具有不同颗粒大小的物质进行比较实验，如砂糖和食盐。

2. 水：实验中所需的水应保持纯净，可使用蒸馏水或去离子水。

3. 量筒：用于准确测量水的体积。

4. 温度计：用于记录实验时水的温度。

5. 手提搅拌器：用于加速物质的溶解过程。

6. 计时器：用于测量物质在水中的溶解时间。

7. 磁力搅拌器（可选）：用于提供均匀的搅拌。

二、实验步骤1. 准备两个温度相等的容器，将等量的水（例如100毫升）分别倒入两个容器中。

2. 将目标物质分别称取等量（例如5克）加入两个容器中，并记下溶质的初始质量。

3. 用手提搅拌器分别在两个容器中搅拌，直到目标物质都完全溶解。

4. 记录下两个容器中的物质溶解所需的时间，并进行比较。

5. 可选操作：使用磁力搅拌器代替手提搅拌器进行实验，以获得均匀的搅拌速度。

三、数据处理和分析1. 比较两种物质在水中的溶解时间，进而比较它们的溶解速度。

2. 分析溶质的颗粒大小对其溶解的影响。

根据实验结果，讨论颗粒大小与溶解速度之间的关系，并提出合理的解释。

3. 讨论实验误差可能的来源，如温度、搅拌速度等。

并提出改进实验的建议，以减小误差。

结论：1. 通过本实验可以发现，物质的颗粒大小对其在水中的溶解速度有明显的影响。

2. 颗粒较小的物质通常溶解速度更快，这是因为颗粒大小较小的物质具有更大的比表面积，能够更快与溶剂接触。

3. 实验结果可以应用于生活和工业实践中，帮助我们更好地理解和掌握物质的溶解特性，以及合理利用这些特性。

延伸思考：1. 实验过程中，还可以考虑加入温度变量，以研究温度对物质溶解速度的影响。

《The Effects of Pollution》高考优秀英语作文The effects of pollution are far-reaching and devastating. Pollution is the introduction of harmful pollutants and contaminants into the environment, and its effects can be felt all over the world. Some of the most common effects of pollution include climate change, destruction of ecosystems, destruction of habitats for numerous species, and health problems for people exposed to polluted air or water.Climate change caused by pollution has had a significant impact on weather patterns and ocean levels across the world. The burning of fossil fuels releases large amounts of carbon dioxide and other greenhouse gases into the atmosphere. These gases trap heat and contribute to global warming, which changes weather patterns, triggers extreme weather events, and causes sea levels to rise.The destruction of ecosystems is another consequence of pollution. Excessive amounts of nitrogen and phosphorus in water run-off can lead to hypoxia, or oxygen depletion, in rivers and coasts. This can create “dead zones” where fish and other organisms can’t survive. Pesticides, industrial chemicals, and sewage have also caused disruption in the natural balance of ecosystems and caused mass die-offs of wildlife.Pollution has also caused destruction of habitats for many species of animals. Habitat destruction from pollution arises from runoff from chemicals and other pollutants into rivers, lakes, and oceans as well as deforestation. This has caused a decrease in the number of species of birds, mammals, reptiles, and other animals, making them more vulnerable to extinction.Finally, polluted air and water can lead to negative health effects, especially for children and those with existing respiratory illnesses. Air pollution can cause respiratory infections, asthma, bronchitis, and cardiovascular diseases, while polluted water can lead to gastrointestinal illnesses and reproductive issues. It is important that both individuals and society at large take steps to reduce pollution to protect the environment and human health.。

何蜀峰，李孟孟，孙杨赢. 水解对低盐鸭肉肌原纤维蛋白结构和功能特性的影响[J]. 食品工业科技，2024，45（2）：84−91. doi:10.13386/j.issn1002-0306.2023040162HE Shufeng, LI Mengmeng, SUN Yangying. Effect of Hydrolysis on Structure and Properties of Duck Myofibrillar Protein in Low-salt Condition[J]. Science and Technology of Food Industry, 2024, 45(2): 84−91. (in Chinese with English abstract). doi:10.13386/j.issn1002-0306.2023040162· 研究与探讨 ·水解对低盐鸭肉肌原纤维蛋白结构和功能特性的影响何蜀峰1，李孟孟1，孙杨赢1,2,*（1.宁波大学食品科学与工程学院，浙江宁波 315800；2.浙江省动物蛋白食品精深加工技术重点实验室，浙江宁波 315800）摘　要：为研究水解时间（0、20、40、60、80 min ）对低盐溶液中鸭肉肌原纤维蛋白的结构和功能特性的影响，本文用胰蛋白酶水解鸭肉肌原纤维蛋白（Myofibrillar protein ，MP ），通过分析水解处理后的水解度、十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis ， SDS-PAGE ）、溶解度、表面疏水性、二级结构、荧光光谱、Zeta 电位和乳化性，对水解物的结构和功能特性进行评估。

结果表明：在低盐溶液中，随着水解时间的延长，溶解度显著升高（P <0.05），表面疏水性先降低后升高，乳化性先升高后降低；当水解时间为40 min 时，水解度为4.15%，鸭肉MP 的溶解度和乳化性达到最高，分别达到60.57%和21.2 m 2/g ；表面疏水性最低（40.85 BPB/μg ）。

The Effects of Light Pollution onWildlifeLight pollution has become a significant issue in today's world, and its impact on wildlife is a growing concern. The excessive and misdirected artificial light produced by human activities has been shown to have detrimental effects on various species of animals, including birds, insects, and marine life. This problem is particularly concerning as it disrupts natural ecosystems and can lead to serious consequences for the affected species. In this response, we will explore the effects of light pollution on wildlife from multiple perspectives, considering the ecological, behavioral, and conservation implications of this pressing issue. From an ecological perspective, light pollution disrupts the natural rhythms and behaviors of wildlife. Many species rely on the natural cycle of light and darkness to regulate their activities, such as foraging, mating, and migration. The introduction of artificial light can confuse and disorient these animals, leading to a range of negative consequences. For example, birds may become disoriented by bright city lights, leading to collisions with buildings or exhaustion from circling around illuminated structures. Similarly, sea turtle hatchlings are known to become disoriented by artificial lights on the shore, causing them to move away from the ocean and towards danger instead of following the natural moonlight to the water. Furthermore, light pollution can have significant impacts on the behavior of nocturnal animals. Many species of insects, for instance, are drawn to artificial lights, which can disrupt their natural behaviors and lead to population declines. This disruption in the food chain can have cascading effects on other species that rely on insects as a food source, ultimately impacting the balance of entire ecosystems. The ecological implications of light pollution are therefore far-reaching and can have serious consequencesfor the stability and health of natural environments. From a behavioral perspective, the effects of light pollution on wildlife are equally concerning. Many animals rely on visual cues for navigation, communication, and finding food. The presence of artificial light can interfere with these essential behaviors, leading to increased stress and reduced reproductive success in affected species.For example, studies have shown that artificial light can disrupt the courtshipand mating behaviors of certain bird species, leading to decreased breeding success and population declines. Similarly, the disruption of natural light cues can affect the ability of some species to find food, leading to decreased foraging success and potential starvation. Moreover, the effects of light pollution on wildlife can also have significant conservation implications. As the human population continues to grow and urban areas expand, the prevalence of artificial light is only expected to increase. This poses a serious threat to many species of wildlife, particularly those that are already facing other pressures such ashabitat loss and climate change. Conservation efforts must therefore take into account the impact of light pollution on wildlife and work to mitigate its effects. This may involve implementing measures to reduce the spread of artificial light, such as using more efficient and targeted lighting designs, as well as creating dark sky reserves to protect critical habitats from excessive light pollution. In conclusion, the effects of light pollution on wildlife are a pressing and multifaceted issue that demands attention and action. From an ecological perspective, light pollution disrupts natural behaviors and rhythms, leading to a range of negative consequences for affected species. Behaviorally, the presence of artificial light can interfere with essential behaviors such as navigation and foraging, leading to increased stress and reduced reproductive success. Additionally, the conservation implications of light pollution are significant, as it poses a growing threat to many species already facing other pressures. Addressing this issue will require a concerted effort to reduce the spread of artificial light and protect critical habitats from excessive light pollution. By doing so, we can help mitigate the impacts of light pollution on wildlife and work towards a more sustainable and harmonious coexistence between humans and thenatural world.。

邵阳学院继续教育学位英语考试真题全文共3篇示例，供读者参考篇1Title: Shaoyang College Continuing Education Degree English Exam QuestionsShaoyang College offers a variety of courses and programs through its continuing education department, allowing individuals to pursue higher education degrees while balancing other commitments. As part of the assessment process, students are required to take English exams to demonstrate their language proficiency. Below are some sample questions from the Shaoyang College continuing education degree English exam:Section 1: Reading ComprehensionRead the following passage and answer the questions below.Passage:In recent years, the importance of lifelong learning has been increasingly recognized by individuals and organizations alike. With rapid technological advancements and changing job requirements, it is essential for professionals to continuallyupdate their skills and knowledge to stay relevant in the workforce.Questions:1. What is the main idea of the passage?2. Why is lifelong learning important for professionals?3. How can individuals benefit from continually updating their skills and knowledge?Section 2: Listening ComprehensionListen to the audio clip and answer the following questions.Audio Clip:You will hear a conversation between two students discussing their experiences in the continuing education program.Questions:1. What program are the students enrolled in?2. What challenges do they face as working professionals studying part-time?3. How do they plan to overcome these challenges?Section 3: WritingChoose one of the following topics and write a short essay (200-300 words) on it.1. The benefits of continuing education for professional development.2. The impact of technology on lifelong learning.3. Strategies for balancing work, studies, and personal life asa continuing education student.These are just a few examples of the types of questions that may be included in the Shaoyang College continuing education degree English exam. By testing students' reading, listening, and writing skills, the exam aims to assess their overall proficiency in the English language and their ability to communicate effectively in an academic setting. Good luck to all the students who will be taking the exam!篇2ShaoYang University Continuing Education Degree English TestSection 1: Reading Comprehension (40 points)Read the passage below and answer the questions that follow:Climate change is one of the greatest threats facing the world today. As the Earth's temperature rises, it is causing more frequent and severe weather events such as hurricanes, droughts, and floods. The consequences of climate change are already being felt around the globe, with devastating effects on ecosystems, economies, and human health.1. What is one of the greatest threats facing the world today?a) Pollutionb) Climate changec) Deforestationd) Overpopulation2. What are some of the consequences of climate change?a) More frequent and severe weather eventsb) Increased biodiversityc) Improved crop yieldsd) Cleaner air3. How are ecosystems being affected by climate change?a) They are thrivingb) They are not affected at allc) They are being devastatedd) They are adapting easily4. How is human health impacted by climate change?a) It has no impact on human healthb) It improves human healthc) It has negative effects on human healthd) It increases life expectancySection 2: Writing (60 points)Choose one of the following topics and write an essay of at least 300 words:1. The importance of renewable energy sources in combating climate change.2. Discuss the role of education in raising awareness about environmental issues.3. The effects of climate change on biodiversity and ecosystems.4. How individuals can contribute to mitigating climate change in their daily lives.Section 3: Listening Comprehension (40 points)Listen to the audio recordings and answer the questions that follow.1. What is the main topic of the recording?a) The benefits of recyclingb) The importance of reducing carbon emissionsc) The impact of deforestation on the environmentd) The significance of renewable energy sources2. What action does the speaker suggest individuals can take to reduce their carbon footprint?a) Drive less and carpool moreb) Use more plastic bagsc) Avoid recyclingd) Waste energy3. Why is it important to conserve water?a) Because water is an unlimited resourceb) Because water is not essential for lifec) Because water scarcity is a global issued) Because water pollution is not a problemSection 4: Speaking (60 points)Part 1: Introduction (10 points)Introduce yourself and discuss your interest in environmental issues.Part 2: Role Play (30 points)You are a member of a local environmental club. Discuss with your partner ways in which the club can raise awareness about climate change in the community.Part 3: Discussion (20 points)Discuss with the examiner the role of governments in combating climate change and the responsibility of individuals in addressing environmental issues.Good luck with your test!篇3Title: Shaoyang College Continuing Education Degree English Exam Sample QuestionsIntroduction:Shaoyang College offers continuing education programs for students pursuing higher degrees in various fields. One of the requirements for graduation is passing the English exam, which tests students' proficiency in the language. Below are some sample questions that students can expect to see on the exam.Listening Section:1. Listen to the conversation between a student and a library staff member. What is the student looking for?A. A book on historyB. A magazine on fashionC. A fiction novelD. A research paper on economics2. Listen to the announcement. What is the speaker asking students to do?A. Sign up for a workshopB. Submit their assignmentsC. Attend a lectureD. Join a study groupReading Section:Read the following passage and answer the questions that follow.According to a recent study, students who participate in extracurricular activities have better academic performance than those who do not. The study found that students who are involved in sports, clubs, or volunteer work tend to have higher GPA scores and lower dropout rates.3. What is the main idea of the passage?A. Extracurricular activities improve students' social skills.B. Participating in extracurricular activities improves academic performance.C. Students who do not participate in extracurricular activities are more likely to drop out of school.D. Extracurricular activities are just as important as academic studies.4. According to the passage, which of the following statements is true?A. Students who participate in sports have lower GPA scores.B. Students who do not participate in clubs have better academic performance.C. Extracurricular activities have no impact on students' academic performance.D. Students who volunteer tend to have higher GPA scores.Writing Section:Write an essay on the following topic."In your opinion, what are the benefits of studying abroad? Do you think it is worth the cost? Support your argument with examples and evidence."Conclusion:The English exam at Shaoyang College is designed to assess students' language skills and proficiency. By practicing with sample questions like the ones above, students can better prepare for the exam and increase their chances of success. Good luck!。

The Effects of Climate Change on OceanEcosystemsClimate change is a phenomenon that has been affecting various aspects of our planet, including ocean ecosystems. The continuous increase in greenhouse gas emissions has led to rising sea levels, warming oceans, and ocean acidification, which have all had significant impacts on marine life. In this essay, we will delve into the effects of climate change on ocean ecosystems from different perspectives. The first perspective we will consider is that of marine life. The warming of the oceans has led to significant changes in the behavior and patterns of marine species. For instance, some species have been forced to migrate to cooler waters, while others have altered their breeding seasons and migration patterns. The warming of the oceans has also led to coral bleaching, which has devastating effects on the ecosystem. Coral reefs support a significant proportion of marine biodiversity and provide habitats for numerous species. The death of coral reefs could lead to the extinction of many marine species, which could have catastrophic effects on the ecosystem. The second perspective we will consider is that of humans. The effects of climate change on ocean ecosystems have significant implications for human life. For example, the loss of coral reefs could lead to the loss of livelihoods for millions of people who rely on fishing and tourism. Additionally, the warming of the oceans could lead to the spread of diseases, which could have devastating effects on human health. The rise in sea levels could also lead to the displacement of millions of people living in coastal areas. The third perspective we will consider is that of policymakers. Climate change is a global issue that requires collective action from policymakers. The effects of climate change on ocean ecosystems should be a key consideration in policymaking. Policymakers should develop policies that promote the reduction of greenhouse gas emissions and the protection of marine ecosystems. Additionally, policies should be put in place to ensure that the impacts of climate change on marine life are mitigated, and that affected communities are supported. The fourth perspective we will consider is that of the economy. The effects of climate change on ocean ecosystems could have significant economic implications. For instance, the loss ofcoral reefs could lead to a decline in tourism, which could have a ripple effect on the economy. Additionally, the loss of marine biodiversity could lead to a decline in fish stocks, which could have significant implications for the fishing industry. However, there are also economic opportunities that could arise from the mitigation of climate change. For instance, the development of renewable energy could create new job opportunities and stimulate economic growth. The fifth perspective we will consider is that of future generations. The effects of climate change on ocean ecosystems could have long-term implications for future generations. The loss of marine biodiversity could lead to the extinction of many species, which could have irreversible effects on the ecosystem. Additionally, the rise in sea levels could lead to the displacement of millions of people, which could have significant social and economic implications. It is therefore important that we take action to mitigate the effects of climate change on ocean ecosystems to ensure that future generations inherit a healthy and sustainable planet. In conclusion, climate change has had significant effects on ocean ecosystems, affecting marine life, humans, policymakers, the economy, and future generations. It is therefore important that we take collective action to mitigate the effects of climate change on ocean ecosystems. This can be achieved through the reduction of greenhouse gas emissions, the protection of marine ecosystems, the development of policies that support affected communities, and the exploration of economic opportunities that arise from the mitigation of climate change. By taking action, we can ensure that our planet remains healthy and sustainable for generations to come.。

The Impact of Climate Change onBiodiversityClimate change is a pressing issue that has far-reaching consequences for our planet, particularly when it comes to biodiversity. The impact of climate change on biodiversity is profound and multifaceted, affecting ecosystems, species, and ultimately, the delicate balance of life on Earth. One of the most immediate and visible effects of climate change on biodiversity is the loss of habitat. As temperatures rise and weather patterns become more unpredictable, many species are struggling to adapt to their changing environments. This often leads to a loss of habitat, as plants and animals are unable to survive in their traditional ecosystems. Furthermore, climate change is also leading to shifts in the distribution of species. As temperatures rise, many species are moving towards the poles or to higher elevations in search of cooler climates. This can disruptentire ecosystems, as species that were once separated by geographical barriers are now coming into contact with one another. This can lead to competition for resources, as well as the spread of diseases and invasive species. In some cases, species may be unable to find suitable habitats in their new locations, leading to population declines and even extinctions. Another significant impact of climate change on biodiversity is the loss of biodiversity hotspots. These are areas with high levels of species diversity and endemism, meaning that they are home to many species that are found nowhere else on Earth. Climate change is putting these hotspots at risk, as rising temperatures and changing precipitation patterns threaten the survival of many species. This is particularly concerning because biodiversity hotspots are often crucial for the functioning of entire ecosystems, providing important services such as pollination, seed dispersal, and nutrient cycling. In addition to these direct impacts on species and ecosystems, climate change is also affecting the relationships between species. Many species rely on each other for survival, forming complex networks of interactions such as pollination, predation, and competition. As the climate changes, these relationships can be disrupted, leading to cascading effects throughout the ecosystem. For example, if a pollinator species is unable to survive in itstraditional habitat due to climate change, this can have far-reaching consequences for the plants that rely on it for pollination, as well as for the animals that feed on those plants. Overall, the impact of climate change on biodiversity is a critical issue that requires urgent action. It is not just a matter of saving individual species, but of preserving the intricate web of life that sustains our planet. By addressing the root causes of climate change and taking steps to mitigate its effects, we can help protect biodiversity and ensure a healthy and vibrant planet for future generations. It is crucial that we work together to address this global challenge, and that we prioritize the conservation of biodiversity as a key component of our efforts to combat climate change. Only by recognizing the interconnectedness of all life on Earth can we hope to create a sustainable future for ourselves and for the countless species that share our planet.。

热带亚热带植物学报2022, 30(1): 19 ~ 30Journal of Tropical and Subtropical Botany马尾松与乡土阔叶树种凋落叶木质素降解的混合效应李勋1, 张艳1, 覃宇2, 张健3*(1. 四川民族学院，横断山区生态修复与特色产业培育研究中心，四川康定626001；2. 阿坝师范学院，四川汶川623002；3. 四川农业大学林学院，生态林业工程重点实验室，长江上游生态安全协同创新中心，成都611130)摘要：为了解森林凋落叶分解过程中木质素的释放规律，对马尾松(Pinus massoniana, P)、檫木(Sassafras tzumu, S)、香樟(Cinnamomum camphora, C)和香椿(Toona sinensis, T)凋落叶分解过程中的木质素降解率进行了研究。

结果表明，大部分混合凋落叶的木质素在分解过程中出现富集现象，PT和PC组合的木质素含量在第1年较高，之后降低。

而PS、PST、PSC、PCT和PSCT组合在0~6、0~9和15~18个月表现出富集现象，其余时期降低。

在不同分解时期，部分混合凋落叶组合的木质素降解率表现出非加和效应，呈协同效应，以春季和夏季的协同效应较强，秋冬季较弱。

此外，PSCT6121、PSC622、PS64和PC64的木质素降解率在大部分分解时期(≥6/8)表现出协同效应。

因此，马尾松与乡土阔叶树种凋落叶混合后促进了木质素的降解，在马尾松人工林改造过程中，与乡土阔叶树种适当混种，可促进凋落叶中木质素的降解。

关键词：马尾松；乡土树种；凋落物；木质素doi: 10.11926/jtsb.4408All Rights Reserved.Mixed Effects on Lignin Degradation in the Litter Leaves of Pinusmassoniana and Native Broad-leaved Tree SpeciesLI Xun1, ZHANG Yan1, QIN Yu2, ZHANG Jian3*(1. Research Center for Ecological Restoration and Characteristic Industry Cultivation in Hengduan Mountains Region, Sichuan Minzu College, Kangding626000, Sichuan, China; 2. Aba Teachers University, Wenchuan 623002, Sichuan, China; 3. Key Laboratory of Forestry Ecological Engineering in Sichuan,Collaborative Innovation Center of Ecological Security in the Upper Reaches of Yangtze River, Sichuan Agricultural University,Chengdu 611130, China)Abstract: To understand the release rule of lignin in the decomposition process of forest leaf litter, the lignindegradation rate of leaf litter of Pinus massoniana(P), Sassafras tzumu(S), Cinnamomum camphora(C) andToona sinensis(T) was studied. The results showed that lignin in most of mixed litter was enriched duringdecomposition. The lignin content in combination of PT and PC was high in the first year, and then decreased.However, the lignin content in combination of PS, PST, PSC, PCT and PSCT were enriched at 0-6, 0-9 and 15-18 months, and decreased at other periods. At all decomposition stages, the degradation rate of lignin in somemixed litters showed synergistic effect rather than additive effect, the synergistic effect was stronger in summerand winter than in other seasons. Besides, the lignin degradation rate of PSCT6121, PSC622, PS64 and PC64收稿日期: 2021-03-09 接受日期: 2021-05-19基金项目：国家自然科学基金项目(31370628); 四川省科技支撑计划项目(12ZC0017); 四川民族学院自办科研项目(XYZB2003ZA, XYZB2016ZB); 四川民族学院特色科研孵化项目(KBFH2103); 四川省大学生创新创业训练计划项目(S202011661092, S202011661106, S202011661090)资助This work was supported by the National Natural Science Foundation of China (Grant No. 31370628), the Project for Science and Technology Support ofSichuan (Grant No. 12ZC0017), the Project for Scientific Research of Sichuan Minzu College (Grant No. ZYZB2003ZA, XYZB2016ZB), the Project forCharacteristic Research Incubation of Sichuan Minzu College (Grant No. KBFH2103), and the Project for Innovation and Entrepreneurship Training forCollege Students in Sichuan (Grant No. S202011661092, S202011661106, S202011661090).作者简介：李勋，男，博士，主要从事长江中上游马尾松低效人工林改造。

同离子效应英文The Phenomenon of the Common Ion EffectThe common ion effect is a fundamental principle in chemistry that describes the behavior of ionic solutions when they are mixed with a solution containing a common ion. This effect has significant implications in various fields, including analytical chemistry, biochemistry, and environmental science. In this essay, we will explore the concept of the common ion effect, its underlying principles, and its practical applications.The common ion effect arises when a solute is added to a solution containing a salt that has an ion in common with the added solute. This addition of a common ion results in a decrease in the solubility of the salt or a shift in the equilibrium of the solution. The magnitude of the common ion effect depends on the concentration of the common ion and the equilibrium constant of the reaction.To understand the common ion effect, let us consider the dissociation of a weak acid, such as acetic acid (CH3COOH), in water. In this system, the equilibrium can be represented by the following equation:CH3COOH + H2O ⇌ CH3COO- + H+The equilibrium constant for this reaction is given by the expression:Kc = [CH3COO-] [H+] / [CH3COOH]Now, if we add a solute that contains the acetate ion (CH3COO-), such as sodium acetate (CH3COONa), the concentration of the acetate ion in the solution will increase. According to the Le Chatelier's principle, the system will shift to counteract this change and restore the equilibrium. In this case, the system will shift to decrease the concentration of the acetate ion, which means that the concentration of the acetic acid (CH3COOH) will increase, and the pH of the solution will decrease.The common ion effect has several important applications in various fields of chemistry and biology. In analytical chemistry, the common ion effect is used in precipitation reactions, where the solubility of a salt is reduced by the presence of a common ion. This principle is employed in the precipitation of ions, such as silver chloride (AgCl)or barium sulfate (BaSO4), for quantitative analysis.In biochemistry, the common ion effect plays a crucial role in the regulation of pH in biological systems. The human body, for example,maintains a delicate balance of pH through the use of buffer systems, such as the carbonate-bicarbonate buffer system. In this system, the presence of a common ion, such as the bicarbonate ion (HCO3-), helps to regulate the pH of the blood and other bodily fluids.The common ion effect also has important applications in environmental science. In water treatment, the common ion effect is used to remove unwanted ions from water by precipitation. For instance, the addition of lime (calcium hydroxide, Ca(OH)2) to hard water can precipitate calcium carbonate (CaCO3) due to the common ion effect, effectively softening the water.Furthermore, the common ion effect is crucial in the understanding of various chemical equilibria, such as the solubility of sparingly soluble salts, the dissociation of weak acids and bases, and the formation of complex ions. By considering the common ion effect, chemists can accurately predict the behavior of these systems and design efficient separation and purification processes.In conclusion, the common ion effect is a fundamental principle in chemistry that has far-reaching implications in various fields. By understanding the underlying principles and practical applications of the common ion effect, chemists, biochemists, and environmental scientists can develop more effective and efficient solutions to a wide range of problems.。

the el nino effect ieltsThe El Nino Effect and Its Impact on IELTSThe El Nino effect, a natural phenomenon that occurs every few years, has a significant impact on global weather patterns and can have profound consequences for examinations such as the International English Language Testing System (IELTS). This essay will explore the El Nino effect, its potential impact on IELTS, and how test-takers and exam organizers can prepare for it.The El Nino effect is a climatic event that occurs when trade winds in the Pacific Ocean weaken, allowing warm water to flow towards the western Pacific. This shift in water temperatures and atmospheric patterns can lead to extreme weather events such as heavy rainfall, droughts, and extreme temperatures in various regions around the world.For IELTS test-takers, the El Nino effect can pose several challenges. Firstly, extreme weather events can disrupt travel plans, making it difficult for candidates to reach their exam centers on time. Secondly, the El Nino effect can lead to changes in temperature and humidity levels, which can affect test-takers' physical comfort and concentration during the exam. Additionally, the El Nino effect may also influence the availability of exam centers and resources, potentially leading to delays or cancellations.To mitigate the impact of the El Nino effect on IELTS, both test-takers and exam organizers need to take proactive measures. Test-takers should monitor weather updates closely and plan their travel well ahead of time to avoid any potential delays. They should also ensure that they are physically comfortable during the exam by dressing appropriately and taking necessary precautions to manage the heat or cold.Exam organizers, on the other hand, should have contingency plans in place to deal with any potential issues arising from the El Nino effect. This could include alternative exam centers, flexible scheduling options, and additional resources to ensure that the exam can be conducted smoothly even in the face of adverse weatherconditions.In conclusion, the El Nino effect can have a significant impact on IELTS and other global exams. By planning ahead and taking proactive measures, both test-takers and exam organizers can minimize the potential risks and ensure that the exam is conducted fairly and effectively.。

the effects of light on plant 雅思阅读摘要：I.引言- 光对植物生长的重要性- 光对植物的影响II.光合作用- 光合作用的定义- 光合作用的过程- 光合作用对植物生长的影响III.光的形态建成- 形态建成的定义- 形态建成的过程- 形态建成对植物生长的影响IV.光周期现象- 光周期现象的定义- 光周期现象的过程- 光周期现象对植物生长的影响V.光对植物生长的影响- 光的强度对植物生长的影响- 光的方向对植物生长的影响- 光周期对植物生长的影响VI.结论- 光对植物生长的重要性- 光对植物的影响正文：I.引言光对植物生长具有重要意义，植物通过光合作用将阳光能转化为化学能，为自身生长提供能量。

此外，植物的生长和发育过程也受到光的调控。

本文将详细探讨光对植物的影响，包括光合作用、形态建成和光周期现象等方面。

II.光合作用光合作用是植物通过吸收阳光能将水和二氧化碳转化为葡萄糖和氧气的过程。

在这个过程中，植物利用阳光能进行光激发，将电子从基态跃迁到激发态，最终传递给辅酶NADP+，形成NADPH。

NADPH 和ATP 为碳的固定提供能量，使二氧化碳转化为葡萄糖。

光合作用对植物生长具有重要意义，它为植物提供了生长所需的能量和物质。

III.形态建成形态建成是植物对环境因素（如光、温度等）的响应，通过调节细胞分裂、细胞伸长和细胞分化等过程，使植物能够适应不同的生长环境。

在光的影响下，植物会产生不同的激素，如生长素、赤霉素和细胞分裂素等，这些激素会影响植物的形态建成。

形态建成对植物生长具有重要影响，它使植物能够更好地适应环境，提高生长效率。

IV.光周期现象光周期现象是指植物对日照长度变化的反应。

不同的植物对光周期的反应不同，有的植物喜欢长日照，有的植物喜欢短日照。

植物通过光周期现象调控自身的生长和发育过程，如开花、结果等。

光周期现象对植物生长具有重要影响，它决定了植物的生长周期和生物钟。

J Gastroenterol 2009; 44:26–46DOI 10.1007/s00535-008-2296-0ReviewProbiotics and immunityA NDREA T.B ORCHERS 1,C ARLO S ELMI 2,3, F REDERICK J. M EYERS 4, C ARL L. K EEN 1, and M. E RIC G ERSHWIN 21Department of Nutrition, Allergy and Clinical Immunology, University of California at Davis, Davis, CA, USA2 Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis, Genome and Biomedical Sciences Facility, 451 Health Sciences Drive, Suite 6510, Davis, CA 95616, USA 3Department of Internal Medicine, IRCCS Istituto Clinico Humanitas, University of Milan, Milan, Italy 4Department of Internal Medicine, University of California at Davis Medical Center, Sacramento, CA, USAProbiotics are defi ned as live microorganisms that, when administered in adequate amounts, confer a health benefi t on the host, including the gastrointestinal tract. While this benefi cial effect was originally thought to stem from improvements in the intestinal microbial balance, there is now substantial evidence that probiot-ics can also provide benefi ts by modulating immune functions. In animal models, probiotic supplementation is able to provide protection from spontaneous and chemically induced colitis by downregulating infl amma-tory cytokines or inducing regulatory mechanisms in a strain-specifi c manner. In animal models of allergen sensitization and murine models of asthma and aller-gic rhinitis, orally administered probiotics can strain-dependently decrease allergen-specifi c IgE production, in part by modulating systemic cytokine production. Certain probiotics have been shown to decrease air-way hyperresponsiveness and infl ammation by inducing regulatory mechanisms. Promising results have been obtained with probiotics in the treatment of human infl ammatory diseases of the intestine and in the pre-vention and treatment of atopic eczema in neonates and infants. However, the fi ndings are too variable to allow fi rm conclusions as to the effectiveness of specifi c pro-biotics in these conditions.Key words: microfl ora, nutritional immunology, dietary supplement, innate immunity, vaccineIntroductionThe gastrointestinal tract constitutes an important inter-face between host and environment and, as such, has thedual role of excluding pathogens while facilitating the absorption of nutrients. It is colonized by an estimated 1014 microbes, with the density of colonization increas-ing from the stomach to the distal colon. Only a minor-ity (300–500) of the species present in the intestinal microfl ora can currently be cultured in vitro, whereas a vast majority of intestinal microorganisms cannot. Com-mensal bacteria participate in both tasks of the gastro-intestinal tract: some help in the absorption of otherwise indigestible nutrients, especially complex carbohydrates, and some contribute to colonization resistance, that is, the ability to inhibit colonization or overgrowth of potentially pathogenic microorganisms, by producing antimicrobial substances, competing for adhesion sites and nutrients, and stimulating the immune system.Recent research efforts have demonstrated that infl ammation and immunity changes in general are criti-cal to the development of nearly every complex condi-tion, as well represented by the autoimmunity scenario, which now involves new, previously unsuspected clinical entities 1 and mechanisms.2 Similarly, recent evidence has provided new insights into the immune-mediated mechanisms in metabolic diseases.3,4 Taken together, the cumulative data argue for the need to determine new tools to modulate immunity either by enhancing (as in the case of immunodefi ciencies) or by suppressing (such as in the case of allergy) the immune response, and dietary components are ideal candidates in this regard.Probiotics are frequently, though not necessarily, commensal bacteria. The most widely accepted defi ni-tion of probiotics states that they are live microorgan-isms that, when administered in adequate amounts, confer a health benefi t on the host.5 In order to qualify as probiotic, microorganisms should fulfi ll most, if not all, of the criteria listed in Table 1. The established pro-biotics that meet these criteria are generally lactic acid bacteria (LAB), most commonly Lactobacillus and Bifi -dobacterium species, but Lactococcus , Streptococcus ,Received: September 3, 2008 / Accepted: September 3, 2008Reprint requests to: M. E. Gershwinand Enterococcus species, as well as some nonpatho-genic strains of Escherichia coli, and certain yeast strains also qualify. Numerous other LAB have shown probi-otic potential in animal studies. In recent years, evidence has accumulated that probiotic strains can exhibit the same activities as commensal bacteria, including immunomodulation.Gut-associated lymphoid tissue (GALT) is the largest lymphoid tissue of the human body. Its earliest and largest exposure to microbial antigens occurs during the initial intestinal colonization, which starts at birth. The type of colonizing organisms depends on the mode of birth and the mode of feeding, hygiene levels, and medi-cation use. A fairly stable confi guration of permanently colonizing bacteria is reached in children by approxi-mately 4 years of age. The stimuli provided by coloniza-tion with commensal bacteria are essential for the development of a fully functional and balanced immune system, including not only homing of B and T cells to the lamina propria and expansion and maturation of IgA plasmocytes and IgA production but also the induc-tion of tolerance toward innocuous food and microbial antigens.GALT can be divided into areas where lymphocytes are scattered throughout the epithelium and the lamina propria and organized lymphoid tissues, including Peyer’s patches and mesenteric lymph nodes (MLNs).6 Intestinal antigens are delivered to Peyer’s patch den-dritic cells (DCs) via specialized enterocytes called M cells. In addition, lamina propria DCs have been shown to directly sample antigens, including enteropathogenic and commensal bacteria, in the intestinal lumen via transepithelial dendrites without jeopardizing the integ-rity of the epithelial barrier.7,8 This process can be induced by ligation of any of a variety of Toll-like recep-tors (TLRs) expressed on epithelial cells.9 Whereas priming of T cells in Peyer’s patches or MLNs leads to effective local (mucosal) immune responses or toler-ance depending on the encountered antigen, systemic immune responses or tolerance to ingested antigens are likely to be generated in the MLNs.6 The translocation efficiency of commensal (and presumably probiotic) bacteria depends on the bacterial strain and the luminal concentration,10,11 but the percentage of orally adminis-tered commensal bacteria that can be recovered from DCs in MLNs is very small.12 Effi cient killing by mac-rophages and sequestering in MLN DCs largely prevent commensal bacteria from gaining access to the systemic immune compartment.10,12 This indicates that intestinal DC populations are central to the immune-modulating effects of commensal and, by extension, probiotic bacteria.DCs are critical players in both innate and adaptive immunity since they are the most potent antigen-presenting cells and have the ability to activate naïve T cells.13 In addition, they have a critical role in directing helper T-cell responses toward Th1 or Th2, or regula-tory patterns.13 Th1 immune responses critically depend on the ability of DCs to produce interleukin (IL)-12 and are characterized by the production of interferon (IFN)-γ and IL-2, which induce cell-mediated immunity. Th2 immune responses involve IL-4, IL-5, IL-6, and IL-13 and induce humoral immunity. There is now substantial evidence that DCs can direct T cells to assume regula-Table 1.Criteria for the use of probiotics in humansIdentifi ed at the genus, species, and strain level• T he gold standard for species identifi cation is DNA–DNA hybridization; 16S rRNA sequence determination is a suitable substitute, particularly if phenotypic tests are used for confi rmation• Strain typing should be performed by pulsed-fi eld gel electrophoresis• Strain should be deposited in an international culture collectionSafe for food and clinical use• Nonpathogenic• Not degrading the intestinal mucosa• Not carrying transferable antibiotic resistance genes• Not conjugating bile acids• Susceptible to antibioticsAble to survive intestinal transit• Acid and bile tolerantAble to adhere to mucosal surfacesAble to colonize the human intestine or vagina (at least temporarily)Producing antimicrobial substancesAble to antagonize pathogenic bacteriaPossessing clinically documented and validated health effects• At least one phase 2 study, preferably independent confi rmation of results by another centerStable during processing and storagetory functions and thereby induce oral tolerance.6,14 One of the most extensively studied mechanisms for the induction of regulatory T cells by DCs is the release of IL-10 or transforming growth factor (TGF)-β, resulting in Tr1 and Th3 cells regulatory T cells that act through the secretion of IL-10 and TGF-β, respectively. Other mechanisms involve the production of immunosup-pressive IFN-α or the induction of indoleamine 2,3-dioxygenase (IDO), which is an immunoregulatory enzyme with key functions in the interactions between DCs and regulatory T cells that ultimately result in immunosuppression. DC immaturity or partial matura-tion at the time of antigen presentation has also been implicated in tolerance induction,15 particularly as a result of their interaction with apoptotic cells.16 Since tolerance to innocuous food and commensal antigens is a prerequisite for gastrointestinal immune homeostasis, it is not surprising that intestinal DCs differ phenotypi-cally, and functionally, from peripheral DCs in that they preferentially prime antigen-specifi c CD4+ T cells to produce Th2 cytokines or to differentiate into regula-tory T cells and induce tolerance.6,14 Yet, it remains unclear whether this tolerogenic phenotype of intestinal DCs is due to their derivation from distinct lineages, their tissue microenvironment, or, in the case of com-mensal and other nonpathogenic bacteria, to differen-tial stimuli provided by key bacterial components. For further data on mucosal immunity and its relationship to disease, we refer to the recent literature.17–25In vitro effects of probiotics on DC phenotypeand functionIn their immature state, DCs are characterized by high capacity for antigen uptake.13 Once they capture an antigen in the presence of appropriate infl ammatory stimuli, they migrate to secondary lymphoid organs and simultaneously undergo a maturation process. This process involves the upregulation of major histocom-patibility complex (MHC) molecules for antigen pre-sentation and of costimulatory molecules, such as CD40, CD54, CD83, and B7.1 and B7.2 (CD80 and CD86) for effective T-cell stimulation. Phenotypic maturation is accompanied by stimulus-specific enhancement of the production of various cytokines that shape the subse-quent T, B, and natural killer (NK) cell responses. In recent years, numerous studies have examined how known and potential probiotics infl uence DC matura-tion and cytokine secretion. Because intestinal DCs are difficult to isolate in sufficient numbers, these experi-ments have focused almost exclusively on human DCs derived from peripheral blood monocytes and on murine bone marrow-derived DCs (BMDCs). There are indica-tions that DCs from the peripheral compartment respond differently to commensal bacteria than do MLN DCs.26 However, there are also data suggesting that the responses of peripheral (human blood) and colonic lamina propria DCs to cell wall components of probiotic strains are qualitatively, though not quantita-tively, similar.27 However, blood myeloid DCs respond differently from monocyte-derived DCs (MDDCs) to probiotic bacteria of intestinal origin.28 Therefore, it remains unclear to what extent the results obtained with MDDCs accurately reflect the responses of at least a subset of intestinal DCs. Nonetheless, as is discussed in other sections of this review, certain characteristics of human MDDCs and murine BMDCs correspond rather well to the results of in vivo studies.Incubation of live or UV-killed probiotics and other LAB induces distinct and strain-specifi c maturation and cytokine patterns in both human MDDCs and murine BMDCs (see Tables 2–4). Overall, there are at least two types of LAB: strong and weak inducers of IL-12 andTable 2. Infl uence of live probiotic and commensal bacteria on human MDDC maturation and cytokine productionBacterium Strain Bacterial dose(bacteria/DCs)CD80CD83CD86CD40MHC II IL-10IL-12RefLactobacillus gasseri ATCC 199921000↑↑↑↑↑±↑34 L. johnsonii ATCC 332001000 ↑↑↑↑↑±↑34 L. plantarum NCIMB 882610 ↑↑↑↑↑↑201 L. plantarum NCIMB 882 10 ↑↑↑↑↑41 L. plantarum ATCC 801410 ↑↑↑↑↑↑↑145 L. reuteri ATCC 232721000 ↑↑↑↑↑±↑34 L. rhamnosus GG 5 ↑(low)↑↑±141L. rhamnosus Numico Researchisolate20 ↑↑±±±35 L. salivarius W2410 ±±±±37 Bifi dobacterium bifi dum W2310 ±↑±↑37 B. infantis W5210 ±↑±↑37 MDDC, monocyte-derived dendritic cells; MHC, major histocompatibility complex; IL, interleukin; DCs, dendritic cellsTable 3. Infl uence of UV-killed probiotic and commensal bacteria on human MDDC maturation and cytokine production Bacterium Strain Bacterial dose CD80CD83CD86CD40MHC II IL-10IL-12Ref L. acidophilus X3730–50 μg/1.2 × 106 DCs↑↑↑↑↑↑30 L. acidophilus X37 25 μg/106 DCs↑↑↑↑↑↑31 L. acidophilus X37105↑↑↑↑↑↑28L. paracasei DSM 1224625 μg/106 DCs↑↑±±↑↑ (Slight)28,31 L. reuteri DSM 1224625 μg/106 DCs↑↑↑↑↑↑ (Slight)31 L. reuteri DSM 1224630–50 μg/1.2 × 106 DCs↑↑↑↑↑±30 L. rhamnosus GG30–50 μg/1.2 × 106 DCs↑↑↑↑↑ (Slight)±30 B. bifi dum S13130–50 μg/1.2 × 106 DCs↑↑↑↑↑±30 B. bifi dum S13.125 μg/106 DCs↑↑↑↑↑↑ (Slight)31 B. lactis Bb1230–50 μg/1.2 × 106 DCs↑↑↑↑↑↑±30 B. longum Q4530–50 μg/1.2 × 106 DCs↑↑↑↑↑↑±30 B. longum Q4630–50 μg/1.2 × 106 DCs↑↑↑↑↑↑±30 B. longum Q4625 μg/106 DCs↑↑±±↑↑ (Slight)28,31Table 4.Effect of LAB on murine BMDCsBacteria Strain Bacterial dose CD86CD40MHC II IL-10IL-12Reference L. casei a CHCC3139up to 10 μg/1.4 × 106 DCs↑↑↑↑202 L. fermentum a Lb20up to 10 μg/1.4 × 106 DCs↑↑↑↑202 L. johnsonii a La1up to 10 μg/1.4 × 106 DCs↑↑↑↑202 L. plantarum a Lb1up to 10 μg/1.4 × 106 DCs↑↑↑↑202 L. plantarum a299v up to 10 μg/1.4 × 106 DCs↑↑↑Littleeffect202 L. reuteri DSM12246up to 10 μg/1.4 × 106 DCs±↑↑↑202 L. acidophilus NCFM10:1↑↑↑↑↑107 L. lactis MG136310:1↑↑↑↑↑107L. rhamnosus Lr3210:1Moderateeffect ±LittleeffectLittleeffectLittleeffect107L. salivarius Ls3310:1Moderateeffect ModerateeffectModerateeffectLittleeffectLittleeffect107LAB, lactic acid bacteria; BMDCs, bone marrow-derived dendritic cells a Note that Christensen et al.202 used γ-irradiated bacteriatumor necrosis factor (TNF)-α production; however, almost all of them induce signifi cant, though quite vari-able, levels of IL-10. Most Bifi dobacterium strains stim-ulate the production of high levels of IL-10, but only modest levels of IL-12 and TNF-α, and this is also the pattern seen with Gram-negative bacteria of the intes-tinal microfl ora.28–30The results of coincubation experiments indicate that there are considerable interactions between bacterial strains that can result in the inhibition or enhancement of DC maturation and IL-12 and IL-10 induction, depending on the combination.30,31 Similar fi ndings have been reported in LAB-stimulated peripheral blood mononuclear cells (PBMCs).32,33 This suggests that the intestinal microflora of the host may have a decisive infl uence on the response to treatment with a specifi c probiotic. Note, however, that this inhibitory effect of weak IL-12 inducers on the inducing capacity of strong inducers is DC-subset dependent, with inhibition seen in MDDCs, but not in blood myeloid DCs.28 Therefore, it remains to be established whether lamina propria DCs are sensitive to the inhibitory effect of the simul-taneous presence of strong and weak IL-12 inducers. DCs that undergo partial or full maturation after incubation with a particular LAB strain also differ in their capacity to stimulate allogeneic/autologous T-cell proliferation and cytokine production27,34–36 and to enhance NK cell cytokine production and cytotoxic-ity.28,31 In addition, when DC maturation is induced by lipopolysaccharide (LPS) with or without added TNF-αand IL-1β, the mere presence of certain LAB strains during this maturation process affects the ability of DCs to polarize the cytokine production of CD4+ T cells.37 Using a similar protocol, it can be shown that Lactoba-cillus rhamnosus GG (LGG) is able to induce T-cell hyporesponsiveness38 and that Lactobacillus reuteriASM20016 or Lactobacillus casei NIZO B255, but not Lactobacillus plantarum NIZO B253, are capable of priming DCs for the induction of regulatory T cells.39 Similar findings have been reported for Lactobacillus paracasei NCC2461 in mixed lymphocyte reactions using murine splenic CD4+ T cells and allogeneic sple-nocytes as accessory cells.40Interactions between bacteria, intestinal epithelial cells, and DCsThere are complex and dynamic interactions between the intestinal epithelium and bacteria on the luminal side, and between the epithelium and the underlying immune system on the basolateral side. Intestinal epi-thelial cells are able to distinguish pathogenic from non-pathogenic bacteria on the basis of their invasiveness and the presence of fl agella,41 although the exact mechanisms that allow them to do so are not fully elu-cidated and likely involve additional mucosal factors.17 Intestinal epithelial cells that have encountered cer-tain bacteria participate in the immune response by producing chemokines and cytokines and upregulating adhesion molecules, thereby attracting and activating immune cells.This aspect has been largely neglected in investiga-tions of the influence of probiotics on DC function. There are, however, studies showing that probiotics and other nonpathogenic LAB or components thereof strain-specifi cally affect the production of the chemo-kine IL-8 and of proinfl ammatory cytokines by intesti-nal epithelial cells.42–48 This ability is further modulated by the presence of leukocytes on the basolateral part of the culture plates.49In turn, experiments where bacteria are added to the apical side and DCs to the basolateral side of an intes-tinal epithelial cell monolayer show that the presence of intestinal epithelium affects the ability of probiotic and other bacteria to induce DC maturation, and par-ticularly the ratio of IL-10 to IL-12 that these DCs release.41,42 In addition, the small fraction of DCs that directly sample bacteria by extending dendrites across the intestinal epithelial layer are activated to a different extent than those that only come into contact with soluble mediators produced by epithelial cells that have encountered these bacteria.41 Interestingly, DCs treated with supernatant fractions of epithelial cell–bacteria cocultures or of epithelial cells alone were found to preferentially drive Th2 or regulatory T-cell responses, that is, to induce a “mucosal” DC phenotype, even though peripheral MDDCs were used in these experi-ments.41,42 The production of TGF-β and thymic stromal lymphopoietin by intestinal epithelial cells has been implicated in the induction of this tolerogenic DC phenotype.42,50Probiotics in clinical practiceProbiotics in infl ammatory diseases of the bowel Crohn’s disease (CD) and ulcerative colitis (UC) are two distinct clinical forms of infl ammatory bowel disease (IBD), characterized by chronic relapsing intesti-nal inflammation that is thought to result, similar to other autoimmune diseases, from complex interactions between genetic,51–54 environmental,55–60 and immuno-logical factors.19,61–64 Loss of tolerance to the patient’s own commensal fl ora has been implicated in the devel-opment of both diseases. Decreased levels of Bifi dobac-terium and Lactobacillus strains have been described in fecal samples, whereas raised counts of Enterococcus and Bacteroides species are found in infl amed mucosa of patients with IBD. High levels of infl ammatory cyto-kines (TNF-α and IL-1β) and IL-8 are produced by inflamed colonic mucosa of both UC and CD patients,65–69 while the role of autoantibodies remains to be determined.70 In addition, lamina propria T cells from IBD patients secrete elevated levels of IL-6, and IL-6/STAT-3 signaling is upregulated.71,72 However, there are differences between the two clinical forms of IBD, with lamina propria T cells from CD patients showing Th1 polarization, whereas those of UC patients express Th2 cytokines.73 In addition, there is enhanced production of IL-10 in colonic tissue of UC patients. Interestingly, the vast majority of studies report that natural FoxP3+ CD4+CD25+ regulatory T cells (Tregs) are markedly expanded in colonic lamina propria and MLNs of both UC and CD patients, particularly during active disease, and are functionally normal in vitro.74–78 While data in celiac disease are awaited,25,79 imbalanced microbiota and increased production of proinfl amma-tory cytokines have also been implicated in irritable bowel syndrome (IBS) and in pouchitis. The latter is an infl ammatory condition of the ileal reservoir in patients with ileal pouch anal anastomosis, a surgical procedure used in the management of UC. We note recent litera-ture that reviews the issues of infl ammation, redox, and autoimmunity.80–88The effectiveness of probiotics in clinical trials withUC and CD patientsBecause of the potential of certain probiotic strains to influence the intestinal microbial balance, improve mucosal barrier function, and modulate immune responses, there have been numerous randomized controlled clinical trials of probiotic supplementation in IBD patients. Their results indicate that certain pro-biotics, including E. coli Nissle 1917, LGG, and the probiotic mixture VSL#3 are as effective as standard therapy (most frequently mesalazine) in inducing or maintaining remission in UC or maintaining remissionin CD.73,89–91 However, when added to standard therapy, these and other probiotics do not provide additional benefits compared with standard therapy alone, and most of the probiotics tested to date are not more effec-tive than placebo in inducing or maintaining remission in CD or UC. Only the results of some small trials suggest that various combinations of Bifi dobacterium strains are superior to placebo in preventing relapse in UC.Supplementation of UC patients with a combination of Bifi dobacterium breve strain Yakult, Bifi dobacterium bifi dum strain Yakult, and an unspecifi ed strain of Lac-tobacillus acidophilus was associated with signifi cantly lower clinical activity index, endoscopic activity index, and histological scores compared with mesalazine alone.90 In a small study of patients with UC, symbiotic treatment with Bifi dobacterium longum plus fructooli-gosaccharides and inulin, in addition to their existing medical therapy, tended to lower the sigmoidoscopy score (P= 0.06 compared with placebo).92 Supplementa-tion with a variety of probiotic strains was also reported to be associated with beneficial effects on IBS.73 In addition, VSL#3 was reported to prevent the onset of pouchitis.The mechanisms by which probiotics might amelio-rate IBD, IBS, and pouchitis are rarely addressed in these clinical trials. The symbiotic treatment that tended to lower the sigmoidoscopy score was associated with signifi cantly reduced mRNA expression of TNF-α and IL-1α in biopsy specimens.92 In an open-label study of VSL#3 in patients that had recovered from acute pou-chitis after antibiotic treatment, supplementation with this probiotic mixture also decreased the pouch levels of proinfl ammatory cytokines (TNF-α, IL-1α and IFN-γ), while it increased the production of IL-10.93 Similarly, in patients with IBS, supplementation with Bifi dobacte-rium infantis 35624 or L. rhamnosus GR-1 plus L. reuteri RC-14 decreased IL-12 production and normalized the IL-10:IL-12 ratio.94,95 In addition, administration of VSL#3 resulted in the expansion of colonic Foxp3+ Tregs in conjunction with signifi cantly reduced pouchitis disease activity scores,96 and supplementation with L. rhamnosus GR-1 and L. reuteri RC-14 was associated with an increased frequency of peripheral Tregs in IBS patients.95In healthy volunteers, it was shown that consumption of LGG led to downregulation of the production of proinflammatory cytokines and enhanced the ex vivo synthesis of IL-4 and IL-10 of their CD4+ T cells in response to stimulation with intestinal bacterial prepa-rations.97 Since infl ammatory reactions to the host’s own microfl ora are implicated in IBD, the ability of LGG to skew microflora-induced cytokine production toward an anti-infl ammatory profi le could be of great benefi t. Note, however, that intestinal CD4+ T cells from CD patients and healthy volunteers show differential IFN-γand IL-10 responses to stimulation with autologous intestinal bacteria or with sonicates of probiotics.98 Therefore, it needs to be established whether LGG supplementation can have the same anti-infl ammatory effects in IBD patients as those seen in these healthy volunteers.Data from in vitro studies with infl amed ileal tissue from CD patients suggest that L. casei DN-114001 can not only downregulate TNF-α and IL-6 production but also increase the percentage of lymphocytes undergoing apoptosis, which may contribute to its ability to dimin-ish the number of activated T cells in the lamina propria.67–69 Downregulation of IL-6, which can exhibit antiapoptotic activity, may play a role in this process.69 Indeed, in a mouse model of chronic colitis, treatment with neutralizing IL-6 receptor antibodies prevented macroscopic signs of inflammation in the colon while markedly increasing the number of lamina propria CD4+ T cells undergoing apoptosis.99Probiotics in animal models of colitisThere are numerous animal models of colitis. Mice defi -cient in IL-10 or IL-2 (IL-10−/− and IL-2−/− mice) and HLA-B27 transgenic rats spontaneously develop colitis if they are not kept in germ-free conditions, which high-lights the importance of the intestinal microfl ora in these models. Other models of chronic colitis include the transfer of CD4+CD45RB high or CD4+CD62L+ T cells into severe combined immunodefi ciency (SCID) mice. In addition, chronic colitis can be induced by the intra-rectal administration of trinitrobenzene–sulfonic acid (TNBS). In all of these models, colitis is T-cell mediated and involves mononuclear infiltration of the colonic mucosa along with enhanced production of proinfl am-matory cytokines. Administration of dextran sodium sulfate (DSS) in the drinking water induces a model of acute colitis that requires neither B nor T cells, but is largely macrophage mediated. Although a mononuclear infi ltrate is also seen in the colon of DSS-treated mice, the damage is thought to be due mostly to the toxic effects of DDS rather than the infl ammation.Most available studies focused on the role of various probiotic in the prevention of colitis. None of the strains examined to date was completely effective. However, downregulating the production of proinfl ammatory cytokines and other infl ammatory mediators seems to constitute important mechanisms for the partial amelio-ration of colitis seen with numerous LAB strains in various models.48,100–102 Of note, TNF-α blocking agents are also quite successful in the treatment of patients with CD.In addition, the ability to dampen Th1 responses (IL-12 and IFN-γ production) has been implicated in the preventative effect of Lactobacillus salivarius subspe-。

The Impact of Climate Change on AnimalHabitatsClimate change has had a profound impact on animal habitats around the world, leading to significant disruptions in ecosystems and threatening the survival of many species. The rise in global temperatures, extreme weather events, and changes in precipitation patterns have all contributed to the alteration of natural habitats, forcing animals to adapt or face the risk of extinction. This issue isof great concern to environmentalists, scientists, and conservationists, as the loss of animal habitats not only affects wildlife but also has far-reaching consequences for the balance of the natural world. One of the most visibleeffects of climate change on animal habitats is the loss of polar ice caps and glaciers, particularly in the Arctic and Antarctic regions. Species such as polar bears, seals, and penguins rely on these icy environments for hunting, breeding, and raising their young. As the ice continues to melt at an alarming rate, these animals are being forced to travel greater distances in search of food, leading to increased competition and reduced reproductive success. The iconic image of apolar bear stranded on a melting ice floe has become a symbol of the devastating impact of climate change on animal habitats. In addition to the polar regions, many other ecosystems are experiencing significant changes due to climate change. Forests, for example, are facing increased threats from wildfires, insect infestations, and disease outbreaks, all of which are exacerbated by rising temperatures and changing precipitation patterns. These disturbances not only directly affect the animals that call these forests home but also have cascading effects on the entire ecosystem. For instance, the loss of tree cover can lead to soil erosion, altered water cycles, and a decline in biodiversity, all of which further imperil the survival of countless species. Marine habitats are also being profoundly affected by climate change, with rising sea levels, ocean acidification, and coral bleaching posing significant challenges to marine life. Coral reefs, often referred to as the "rainforests of the sea," are particularly vulnerable to the effects of climate change. The bleaching of corals, caused by increased water temperatures and pollution, not only deprives countless marine species of theirhomes and food sources but also disrupts the delicate balance of the entire ocean ecosystem. The consequences of these habitat disruptions are not limited to the animals directly affected. The loss of biodiversity and the degradation of ecosystems can have far-reaching effects on human societies as well. Many communities around the world rely on healthy ecosystems for food, water, and economic stability. The decline of fish stocks, for example, can have devastating effects on the livelihoods of coastal communities that depend on fishing for their sustenance. Similarly, the loss of pollinators due to habitat destruction can threaten agricultural productivity, leading to food shortages and economic hardship. Addressing the impact of climate change on animal habitats requires a multi-faceted approach that encompasses both mitigation and adaptation strategies. Efforts to reduce greenhouse gas emissions and limit global warming are essential for preventing further habitat destruction. Additionally, conservation initiatives aimed at protecting and restoring natural habitats can help mitigate the impacts of climate change on wildlife. This may involve creating wildlife corridors to allow animals to move to new areas, establishing protected areas, and implementing sustainable land and water management practices. Furthermore, raising awareness about the importance of preserving animal habitats and promoting sustainable coexistence between humans and wildlife is crucial for addressing this issue. Education and advocacy efforts can help foster a greater sense of responsibility and stewardship towards the natural world, encouraging individuals, communities, and governments to take action to protect and restore animal habitats. In conclusion, the impact of climate change on animal habitats is a pressing and complex issue that requires urgent attention and concerted efforts from individuals, communities, and governments around the world. The loss of animal habitats not only threatens the survival of countless species but also has far-reaching consequences for the health of ecosystems and the well-being of human societies. By taking decisive action to address climate change and protect animal habitats, we can work towards ensuring a sustainable and harmonious coexistence between humans and wildlife on our planet.。

科学带来负面效应英文作文Science has brought about negative effects on the environment, leading to pollution and the depletion of natural resources. The rapid industrialization and technological advancements have resulted in the release of harmful chemicals and greenhouse gases, contributing to climate change and global warming.The reliance on scientific advancements has also led to the overexploitation of natural resources, such as deforestation, overfishing, and mining. This has disrupted the delicate balance of ecosystems, leading to the loss of biodiversity and the destruction of habitats for many species.Moreover, the misuse and abuse of scientific discoveries have led to the development and proliferation of destructive weapons, posing a threat to global security and stability. The advancement of nuclear, biological, and chemical weapons has heightened the risk of warfare andconflict, endangering the lives of millions of people.The rapid pace of scientific and technological advancements has also resulted in ethical and moral dilemmas, such as the use of genetic engineering and biotechnology. The manipulation of genes and the creation of genetically modified organisms have raised concerns about the potential consequences on human health and the environment.In addition, the over-reliance on technology and scientific innovations has led to social and psychological issues, such as addiction to electronic devices, social isolation, and the erosion of traditional values and cultural practices. The constant exposure to screens and digital media has also had adverse effects on mental health and well-being.。