Improved Design Criteria and New Trellis Codes for Space–Time Coded Modulation in Slow Fla

PD140 WITH ELECTRONIC CONTROLS IMPROVESNEW HEAD PRESS MACHINE DESIGNCuSTOMERAtlanta GrotnesMachine CompanyCHALLENGEEngineer forBradford Whitea more efficienttank expander/headpressSOLuTIONPD140 variabledisplacement, axialpiston pump withelectronic controlsVALuENew design,manufacturing, maintenance and operating efficiencies CHALLENGEBradford White Corporation, a leading manufacturerof commercial water heaters, needed to replacean aging tank expander/head press that lacked theflexibility to run the wide variety of product modelstheir customers desire.The company’s new product development strategycalled for taller, larger diameter models beyondthe machine’s capabilities. It also lacked the powerto press large tank heads without running at higherthan desired hydraulic pressures. Furthermore,part set-up and changeover consumed 25 –30%of available run time during the one-shiftproduction schedule.Bradford White tasked Atlanta Grotnes withengineering a new machine that would:•Accommodate an ever-increasingrange of tank sizes•Operate at reasonable hydraulic pressures•Reduce set-up and changeover timeDesign criteria dictated the new machine wouldproduce a tank/head assembly every two minutesand be capable of processing more than 80 differentmodels ranging from 12- to 36-inches in diameterand varying in length from 20- to 80-inches. Duringa standard eight-hour shift, Bradford White plannedto change part sizes five to seven times.The new expander/head press envisioned byAtlanta Grotnes chief engineer Archie Tan woulddemand highly variable, rapidly changing hydraulicflow and pressure rates. First, the tank body wouldautomatically be positioned in an entry/exit cradle.Then four hydraulic cylinders would raise the cradle(3.64 gpm) until the body was centered in themachine. Next, a ram cylinder would extendCuSTOMERAtlanta Grotnes Machine Company() has designed and builtmetal forming equipment for a wide variety ofindustries since 1956. The machines are usedfor expanding, shrinking or roll forming – or acombination of the three processes – tomanufacture steel drums, transformers, oilfilters, wheel rims, lawnmower decks, clothesdryers and hot water heaters. For more than10 years Atlanta Grotnes has been a loyalParker customer.Hydraulic Pump Division SuCCESS STORy: Atlanta Grotnes Machine Company(59.97 gpm; 1,000 psi.) to engage one end of the body against the flare tooling (26.67 gpm; 2,000 psi). As the ram retracted, stripper pins would extend (2.16 gpm; 750 psi) to remove the flared body from the tooling. Next, the machine turret would rotate 90° (7.79 gpm; 700 psi) to align the tank body with the head press. A ram cylinder would extend (59.97 gpm; 1,000 psi) to press the head into the tank body (20.00 gpm; 2,000 psi) before retracting (44.75 gpm; 1,000 psi). Finally, the completed head/body assembly would be reloaded in the cradle to roll out of the machine when the cradle tilts (1.70 gpm) and the exit-side cylinders retract (1.19 gpm). Complicating Tan’s design challenge was the fact that exact flow and pressure requirements varied depending upon the diameter and wall thickness of the tank body being produced. A traditional system replete with proportional control and pressure reducing valves (common to the old machine) would require the operatorto perform manual adjustments with each part change – a 20-minute time investment Bradford White sought to eliminate.SOLUTIONSenior Parker hydraulics territory manager Jim Aszman met with Tan and discussed simplifying the high flow/low pressure system using automatic proportional hydraulic pump control. Aszman recommended Parker’sPD140 variable displacement, axial piston pump with electronic controls:•Optimized for fast response and high efficiency in industrial applications, thePD140 would meet the machine’s maximum flow requirement of 60 gpmand offer the agility needed to keeppace with rapidly rising and falling flow rates each 120-second cycle.•Designed with a round, compact housing, the PD140 is quieter than competing “flat surface” pumps. This would help Bradford White meet OSHA’s noise requirement of less than 80 dB at 3 feet.•Featuring digital controls, the PD140 would allow Bradford White to optimize pump performance according to tank size, save and recall part settings on demand and remotely monitor each machine cycle to track system qualityand manufacturing efficiency.“Noise wasa big concern for our customer but thanks to the quiet operation of the Parker pump it was no problemto meet their requirement.”— Archie Tan,chief engineer, Atlanta Grotnes“Set-up is fast and easy now because of the electronic controls. It only takes a secondfor the operatorto dial-up the new settings when a part changes.”— Wayne Bearden, general manager, AtlantaGrotnes Parker’s PD140 gives Bradford White enjoys full electronic control of proportional pressure and displacement, torque limiting, anti-stall and constant flow settings.3/2009© 2009 Parker Hannifin Corporation Parker Hannifin Corporation Hydraulic Pump Division 14249 Industrial Pkwy. Marysville, OH 43040 phone 937 644 3915fax 937 642 /hpsVALUEWith the PD140 solution, Parker’s Hydraulic Pump Division enabled Atlanta Grotnes to provide significant benefits to Bradford White in terms of design, manufacturing, maintenance and operating cost efficiencies:Thanks to electronic proportional control, Atlanta Grotnes was able to design the new expander/press with one standard directional control valve rather than five proportional control valves ($800 per valve). Eight pressure control valves ($400 per valve) were also eliminated for a total cost savings of $7,200. With fewer valves, the new system offers further value in terms of fewer potential leak points.The ability to instantly recall more than 80 tank size settings eliminated 120 minutes of machine downtime per shift by reducing changeover time from 25 to 5 minutes asthe operator is not required to perform manual pump and valve adjustments with each part change (5 minutes per change x 6 changes = 30 minutes = .5 hours vs. 25 minutes per change x 6 changes = 150 minutes = 2.5 hours). As a result, 60 additional tank/head assemblies can be produced per shift.PD140 digital diagnostics will conceivably eliminate one service call per year, saving Bradford White approximately $1,000.By employing a variable displacement pump in the new design, Atlanta Grotnes was able to spec-in a 40 hp motor drawing 46.5 amps at full load current. A fixed displacement pump on the same machine would have necessitated a 75 hp motor drawing 92 amps at full load. As a result, Bradford White will realize annualelectricity cost savings.。

设计质量分析报告英文翻译Quality Analysis Report DesignIntroductionThis report aims to provide an analysis of the quality of a product or service. It evaluates various aspects such as performance, reliability, durability, functionality, and user satisfaction. The report will outline the methods used for the analysis, the findings, and recommendations for improvements.MethodsThe quality analysis was conducted through a combination of quantitative and qualitative approaches. Quantitative evaluation involved collecting data through surveys, questionnaires, and performance metrics. Qualitative evaluation included interviews, user feedback, and expert evaluations.Findings1. Performance: The product/service demonstrated strong performance in terms of speed, accuracy, and responsiveness. It consistently met or exceeded user expectations in tasks such as data processing, calculations, and information retrieval.2. Reliability: The reliability of the product/service was assessed by examining its ability to consistently perform without failures or errors. It was found to have a low failure rate, with only minor glitches reported by a small percentage of users. However, improvements can be made to enhance overall stability and reduce the occurrence of errors.3. Durability: The durability of the product/service was evaluated by assessing its ability to withstand various conditions and maintain functionality over time. It was found to be robust and resistant to physical damage. However, further testing is recommended to assess its long-term durability and lifespan.4. Functionality: The product/service offers a wide range of functionalities that cater to the needs of different users. It was found to be comprehensive and user-friendly, with intuitive interfaces and clear instructions. However, some users expressed the need for additional features and customization options.5. User Satisfaction: User satisfaction was measured through surveys and interviews. The majority of users expressed high levels of satisfaction with the product/service, highlighting its effectivenessand ease of use. However, a small percentage of users reported difficulties in navigating certain features and suggested improvements in terms of user support and documentation.Recommendations1. Improve stability: Address the minor glitches and errors reported by users to enhance the overall stability of the product/service. This can be achieved through rigorous testing, bug fixes, and regular software updates.2. Enhance durability testing: Conduct thorough testing to assess the long-term durability and lifespan of the product/service. This will help identify any potential weaknesses or areas for improvement.3. Develop additional features: Consider adding new features or customization options based on user feedback and emerging market trends. This will enhance the product/service's competitiveness and cater to the evolving needs of users.4. Improve user support and documentation: Provide comprehensive user support and clear documentation to assist users in navigating and utilizing all features of the product/service. This caninclude FAQs, video tutorials, and online forums for user discussions and troubleshooting.ConclusionThe quality analysis report provides an in-depth evaluation of the product/service, highlighting its strengths and areas for improvement. By addressing the recommendations outlined in this report, the product/service can be further enhanced to meet the evolving needs of users and maintain a high level of quality and satisfaction.。

人如何科学自律英语作文Title: The Art of Scientific Self-Discipline。

In the pursuit of personal growth and achievement,self-discipline stands as a cornerstone. It's the ability to control one's impulses, emotions, and behaviors in order to achieve desired goals. When approached scientifically, self-discipline becomes a skill that can be honed and mastered. In this essay, we delve into the principles and strategies that constitute scientific self-discipline.Firstly, understanding the psychology behind self-discipline is crucial. Human behavior is influenced by various factors, including motivation, habits, and willpower. Psychologist Roy Baumeister proposed the concept of ego depletion, suggesting that self-control is a finite resource that can be depleted through exertion. Therefore, it's essential to manage resources wisely and allocate them effectively toward goals.Setting clear and achievable goals is another fundamental aspect of scientific self-discipline. Goals provide direction and purpose, motivating individuals to stay focused and committed. Utilizing the SMART criteria—specific, measurable, achievable, relevant, and time-bound—ensures that goals are well-defined and actionable. Moreover, breaking down larger goals into smaller, manageable tasks facilitates progress and prevents overwhelm.Developing routines and rituals can significantly enhance self-discipline. By establishing consistent habits, individuals reduce the need for deliberation and rely more on automaticity. This conserves cognitive resources and minimizes the likelihood of succumbing to distractions or impulses. Additionally, incorporating self-care practices such as adequate sleep, nutrition, and exercise fosters mental and physical well-being, which are essential for sustained self-discipline.Cultivating self-awareness is a cornerstone ofscientific self-discipline. It involves introspection andreflection to understand one's strengths, weaknesses, and triggers. By identifying potential obstacles and devising preemptive strategies, individuals can navigate challenges more effectively. Mindfulness practices, such as meditation and journaling, enhance self-awareness and promote self-regulation by fostering present-moment awareness and emotional regulation.Social support plays a vital role in fostering self-discipline. Surrounding oneself with like-mindedindividuals who share similar goals and values provides accountability and encouragement. Moreover, seeking mentorship or guidance from those who have achieved success in the desired domain offers valuable insights and guidance. Peer accountability groups or online communities can also serve as sources of motivation and support.Embracing failure as a learning opportunity isessential for building resilience and maintainingscientific self-discipline. Setbacks and obstacles are inevitable on the path to success, but it's how individuals respond to them that determines their progress. Adopting agrowth mindset, which views challenges as opportunities for growth rather than insurmountable obstacles, enables individuals to persevere in the face of adversity.Utilizing technology can enhance the effectiveness of scientific self-discipline. Various apps and tools are available to help track progress, manage time, and stay organized. For example, productivity apps like Todoist or Trello can aid in task management, while habit-tracking apps like Habitica or Streaks facilitate the establishment of new habits. Additionally, utilizing time-blocking techniques or the Pomodoro method can enhance focus and productivity.In conclusion, scientific self-discipline is a multifaceted skill that involves understanding the psychology of behavior, setting clear goals, establishing routines, cultivating self-awareness, seeking social support, embracing failure, and leveraging technology. By integrating these principles and strategies into daily practice, individuals can unleash their full potential and achieve their desired outcomes. Remember, self-disciplineis not about perfection but progress, and each step forward brings you closer to your goals.。

测试工程师改善方案英文IntroductionTesting is a critical aspect of any software development process and ensuring the reliability and quality of the product is the responsibility of the testing engineer. However, the testing process can be complex, time-consuming, and often prone to errors. As a result, it is essential to constantly review and improve testing procedures to ensure efficiency and effectiveness. In this article, we will discuss several improvement strategies for testing engineers to enhance their work processes and ultimately deliver high-quality software products.1. Adopting Agile MethodologyAgile methodology has gained significant popularity in the software development industry due to its iterative and incremental approach to product development. Testing engineers can also benefit from adopting agile practices, such as continuous integration and testing, to ensure that defects are identified and resolved early in the development cycle. By working closely with developers and other team members, testing engineers can gain a better understanding of the system and its requirements, leading to more comprehensive test cases and efficient testing processes.2. Automation of Test CasesManual testing is a time-consuming and labor-intensive process that can be prone to errors. One of the key improvement strategies for testing engineers is to automate test cases wherever possible. By using tools and frameworks for automated testing, testing engineers can increase test coverage, improve the accuracy of tests, and reduce the time and effort required for testing. Additionally, automated tests can be run repeatedly without human intervention, allowing for quicker feedback on the quality of the software product.3. Implementing Continuous Integration and Continuous Deployment (CI/CD)Continuous integration and continuous deployment (CI/CD) practices enable development teams to deliver new features and updates to customers quickly and efficiently. Testing engineers play a crucial role in CI/CD processes by ensuring that the testing environment is stable, that all automated tests are run successfully, and that the quality of the software product meets the required standards. By integrating testing into the CI/CD pipeline, testing engineers can identify and fix defects early, leading to faster release cycles and improved customer satisfaction.4. Enhancing Test Data ManagementEffective test data management is essential for performing accurate and comprehensive testing. Testing engineers should have access to a wide range of test data that accurately represents actual usage scenarios. This can include realistic user profiles, different types ofinput data, and various environmental conditions. By improving test data management processes, testing engineers can create more effective test cases, identify edge cases and potential failure points, and ultimately increase the reliability and robustness of the software product.5. Training and Skill DevelopmentContinuous learning and skill development are crucial for testing engineers to keep pace with the rapid advancements in technology and testing practices. Organizations should invest in training programs and workshops to help testing engineers acquire new skills, learn about emerging testing tools and techniques, and stay updated on industry best practices. Additionally, mentoring programs and knowledge sharing sessions can facilitate the exchange of ideas and experiences among testing engineers, leading to improved collaboration and innovation within the testing team.6. Performance Testing and MonitoringIn addition to functional testing, performance testing and monitoring are essential for ensuring the scalability, reliability, and responsiveness of the software product. Testing engineers should have a deep understanding of performance testing tools and techniques to measure and analyze the performance of the system under various load conditions. By incorporating performance testing into the testing process, testing engineers can identify performance bottlenecks, optimize system resources, and ensure that the software product meets the required performance standards.7. Collaboration and CommunicationEffective communication and collaboration are key for testing engineers to work efficiently with developers, product managers, and other team members. Testing engineers should actively participate in design and requirement discussions, provide feedback on the testability of features, and communicate any issues or concerns that may affect the quality of the software product. By fostering open and transparent communication channels, testing engineers can build stronger relationships with other teams, gain valuable insights into the system, and contribute to the overall success of the software development process.ConclusionTesting engineers play a critical role in ensuring the quality and reliability of software products. By embracing improvement strategies such as adopting agile methodology, automating test cases, implementing CI/CD, enhancing test data management, promoting training and skill development, focusing on performance testing, and emphasizing collaboration and communication, testing engineers can enhance their work processes, increase the efficiency and effectiveness of testing, and ultimately deliver high-quality software products to customers. Continuous improvement and innovation in testing practices are essential for meeting the evolving demands of the software industry and delivering superior user experiences.。

Geometric ModelingGeometric modeling is a crucial aspect of computer-aided design (CAD) and computer graphics. It involves the creation and manipulation of geometric shapes and objects in a virtual environment, allowing designers and engineers tovisualize and analyze complex structures and designs. However, despite its significance, geometric modeling presents several challenges and limitations that need to be addressed to enhance its effectiveness and efficiency. One of the primary issues in geometric modeling is the complexity of representing and manipulating intricate geometric shapes and structures. Many real-world objects and designs are highly complex and may consist of irregular shapes, curved surfaces, and intricate patterns. As a result, accurately representing and manipulating these objects in a virtual environment can be a daunting task, requiring advanced mathematical algorithms and computational techniques. Furthermore, geometric modeling often involves the conversion of physical objects into digital representations, a process known as digitization. This process can be challenging, as it requires precise measurements, accurate data acquisition, and sophisticated scanning and imaging technologies. Inaccuracies or errors in the digitization process can lead to flawed geometric models, impacting the quality and reliability of the final designs and analyses. Another significant challenge in geometric modeling is the integration of different geometric representations and formats. Geometric data may be stored and represented in various formats, such as polygons, splines, NURBS (non-uniform rational B-splines), and point clouds. Integrating and manipulating these diverse representations within a single modeling environment can be complex and may require advanced data conversion and interoperability techniques. Moreover, geometric modeling often involves the creation and manipulation of 3D geometric models, which adds another layer of complexity. 3D modeling requires the representation of objects in three-dimensional space, accounting for depth, perspective, and spatial relationships. This adds to the computational and visualization challenges, as the complexity of 3D models increases exponentially with the number of geometric elements and their interactions. In addition to technical challenges, geometric modeling also raises ethical and legal considerations, particularly in the context of intellectualproperty rights and digital ownership. As geometric models become increasingly sophisticated and realistic, the issue of copyright infringement and unauthorized use of digital designs becomes more prevalent. Protecting the intellectual property of geometric models and ensuring ethical use and distribution of digital designs is a growing concern in the field of geometric modeling. Despite these challenges, advancements in computational geometry, computer graphics, and CAD technologies continue to drive innovation in geometric modeling. New algorithms, software tools, and hardware capabilities are constantly being developed to address the complexities of geometric modeling and enhance its accuracy, efficiency, and usability. From advanced mesh generation techniques to real-time 3D modeling and simulation platforms, the future of geometric modeling holds great promise for designers, engineers, and digital artists. In conclusion, geometric modeling is a critical component of modern design and engineering processes, enabling the creation, visualization, and analysis of complex geometric shapes and structures. However, it presents several challenges, including the complexity of representing intricate shapes, the digitization of physical objects, the integration of diverse geometric representations, and the ethical and legal considerations of digital ownership. Despite these challenges, ongoing advancements in computational geometry and CAD technologies are driving innovation in geometric modeling, offering new opportunities for enhanced design, visualization, and simulation capabilities. As the field continues to evolve, addressing these challenges will be essential to unlocking the full potential of geometric modeling in various industries and applications.。

Materials science材料科学Stone age石器时代Naked eye肉眼Bronze age铜器时代Optical property光学性能Integrated circuit集成电路Mechanical strength机械强度Thermal conductivity导热“Materials science” involves investigating the relationships that exist between the structures and properties of materials. In contrast ,”materials engineering “is ,on the basis of there structure property correlations ,designing or engineering the structure of a material that produce a predetermined set of properties。

，材料工程是根据材料的结构和性质的关系来设计或操纵材料的结构以求制造出一系列可预定的性质。

从功能方面来说，材料科学家的作用是发展或合成新的材料V irtually all important properties of solid materials may be grouped into six different categories: mechanical, electrical, thermal, magnetic, optical ,and deteriorative。

固体材料的所有重要的性质可以分成六个不同的种类，机械性能、电性能、热性能、磁性能、光性能和内耗。

In addition to structure and properties , two other important components are involved in the sciences and engineering of materials , namely“processing”and“performance”.除了组织性能之外，另外两个重要的性质也包括在材料科学和工程之中，即“加工”和“特性”The more familiar an engineer or scientist is with the various characteristics and structure-property relationship，as well as processing techniques of material，the more proficient and confident he or she will be to make judicious materials choices based on these criteria。

SPECIAL REPORT Diagnosis of arrhythmogenic right ventricularcardiomyopathy/dysplasiaProposed Modification of the Task Force CriteriaFrank I.Marcus1*Chair,William J.McKenna2Co-Chair,Duane Sherrill1,Cristina Basso3,Barbara Bauce3,David A.Bluemke4,Hugh Calkins5,Domenico Corrado3,Moniek G.P.J.Cox6,James P.Daubert7,Guy Fontaine10,Kathleen Gear1,Richard Hauer6,Andrea Nava3,Michael H.Picard11,Nikos Protonotarios13,Jeffrey E.Saffitz12,Danita M.Yoerger Sanborn11,Jonathan S.Steinberg9,Harikrishna Tandri5,Gaetano Thiene3,Jeffrey A.Towbin14, Adalena Tsatsopoulou13,Thomas Wichter15,and Wojciech Zareba81University of Arizona,Tucson,AZ;2The Heart Hospital,London,United Kingdom;3University of Padua Medical School,Padua,Italy;4National Institutes of Health,Clinical Center, Bethesda;5Johns Hopkins Hospital,Baltimore,MD;6University Medical Center Utrecht,Utrecht,The Netherlands;7Strong Memorial Hospital,Rochester,NY;8University ofRochester Medical Center,Rochester,NY;9St.Luke’s-Roosevelt Hospital Center,New York,NY;10Hopital La Salpetriere,Paris,France;11Massachusetts General Hospital,Boston,MA;12Beth Israel Deaconess Medical Center,Boston,MA;13Yannis Protonotarios Medical Centre,Hora Naxos,Greece;14Cincinnati Children’s Hospital,Cincinnati,OH;and15Marienhospital Osnabru¨ck,Osnabru¨ck,GermanyOnline publish-ahead-of-print19February2010This paper was guest edited by Douglas P.Zipes*Correspondence to Dr Frank I.Marcus,Sarver Heart Center,1501N Campbell,Rm5153,Box245037,Tucson,AZ.Email fmarcus@This article has been co-published in the April2010issue of Circulation(Vol.121,Issue13)&2010American Heart Association,Inc.and European Society of Cardiology.European Heart Journal(2010)31,806–814doi:10.1093/eurheartj/ehq025Downloaded fromplasia’.2Progression to more diffuse RV disease and left ventricular (LV)involvement,typically affecting the posterior lateral wall,is common.3Predominant LV disease is also recognized.4Postmor-tem diagnosis may require extensive sampling and transillumina-tion.5Disease expression is variable.In the early‘concealed phase’,individuals are often asymptomatic but may nonetheless be at risk of sudden cardiac death,notably during exertion.6In the overt‘electrical phase’,individuals present with symptomatic arrhythmias,and RV morphological abnormalities are readily dis-cernible by conventional ter,diffuse disease may result in biventricular heart failure,whereas ventricular arrhythmias may or may not be present.The ultimate phenotype may resemble dilated cardiomyopathy.Clinical manifestations vary with age and stage of disease.7ARVC/D is considered to be familial with autosomal dominant inheritance,although there are recessive forms(eg,Naxos disease,Carvajal syndrome)that are associated with a cutaneous phenotype.8,9Genetic variations have been found in the desmo-somes that are responsible for cell-to-cell binding10,11(Figure1). Seven genes have been identified that are associated with ARVC/ D:plakoglobin(JUP),12desmoplakin(DSP),13plakophilin-2 (PKP2),14desmoglein-2(DSG2),15,16desmocollin-2(DSC2),17,18 transforming growth factor beta-3(TGFß3),19and TMEM43.20 Mutations in RYR2coding the ryanodine receptor have been reported in ARVC/D in patients with an arrhythmic presentation (stress-induced bidirectional ventricular tachycardia)in the absence of significant electrocardiographic or structural abnormal-ities.At present,catecholaminergic polymorphic ventricular tachycardia is considered a disorder distinct from ARVC/D.11Pre-liminary observations suggest that the mechanical defect of the desmosomes alters function of the gap junction.Electrocardio-graphic(ECG)changes and arrhythmias may develop before histo-logical evidence of myocyte loss or clinical evidence of RV dysfunction.21,22It has been proposed that similar clinical pheno-types occur that are based on disruption of a‘final common pathway’by mutations in genes encoding proteins in the defined desmosomal pathway.23Recognition of the genetic basis of ARVC/D facilitates examination of the pathogenesis in relation to arrhythmogenesis and disease progression.24It has been suggested that patients with ARVC/D may be predis-posed or susceptible to viral myocarditis,which could lead to a decrease in cardiac function and accelerate progression of the disease.25–27The link between ARVC/D and myocarditis is still undefined.BackgroundThe original1994International Task Force criteria for the clinical diagnosis of ARVC/D were based on structural,histological, ECG,arrhythmic,and familial features of the disease28(Table1).phy.Arrhythmias of RV origin,another cardinal feature of ARVC/D,was designated a minor criterion because of its occur-rence in other diseases,particularly idiopathic RV outflow tract tachycardia.Furthermore,the1994criteria focused on RV disease manifestations and stipulated the absence of or only mildLV involvement because of the need to exclude common disorderssuch as ischemic heart disease and dilated cardiomyopathy.At the time of the publication of the original Task Force guide-lines,clinical experience with ARVC/D was dominated by sympto-matic index cases and sudden cardiac death victims–the overt or severe end of the disease spectrum.Consequently,the1994cri-teria were highly specific,but they lacked sensitivity for early and familial disease.29–31Over the past15years,additional ECG markers have been pro-posed.32–34In addition,the genetic basis of the disease has been recognized,with the potential for mutation analysis.Experiencewith quantification of imaging criteria of ARVC/D has increased,and newer imaging techniques have been introduced,such as contrast-enhanced echocardiography,3-dimensional echocardio-graphy,cardiovascular magnetic resonance with late enhancement,and electroanatomic voltage mapping.35–40Figure1The cardiac desmosome and proposed roles of the desmosome in(A)supporting structural stability through cell–cell adhesion,(B)regulating transcription of genes involved in adi-pogenesis and apoptosis,and maintaining proper electrical con-ductivity through regulation of(C)gap junctions and(D)calcium homeostasis.Dsc2indicates desmocollin-2;Dsg2, desmoglein-2;Dsp,desmoplakin;Pkg,plakoglobin;Pkp2, plakophilin-2;and PM,plasma membrane.Reprinted by per-mission from Macmillan Publishers Ltd:Nat Clin Pract CardiovascMed11,&2008.at Peking University on March 6, 2011Downloaded from.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Table 1Comparison of original and revised task force criteriaOriginal task force criteriaRevised task force criteriaI.Global or regional dysfunction and structural alterations*Major†Severe dilatation and reduction of RV ejection fraction with no (or only mild)LV impairment†Localized RV aneurysms (akinetic or dyskinetic areas with diastolic bulging)†Severe segmental dilatation of the RVBy 2D echo:†Regional RV akinesia,dyskinesia,or aneurysm †and 1of the following (end diastole):—PLAX RVOT 32mm (corrected for body size [PLAX/BSA] 19mm/m 2)—PSAX RVOT 36mm (corrected for body size [PSAX/BSA] 21mm/m 2)—or fractional area change 33%By MRI:†Regional RV akinesia or dyskinesia or dyssynchronous RV contraction †and 1of the following:—Ratio of RV end-diastolic volume to BSA 110mL/m 2(male)or 100mL/m 2(female)—or RV ejection fraction 40%By RV angiography:†Regional RV akinesia,dyskinesia,or aneurysmMinor†Mild global RV dilatation and/or ejection fraction reduction with normal LV†Mild segmental dilatation of the RV †Regional RV hypokinesiaBy 2D echo:†Regional RV akinesia or dyskinesia †and 1of the following (end diastole):—PLAX RVOT 29to ,32mm (corrected for body size [PLAX/BSA] 16to,19mm/m 2)—PSAX RVOT 32to ,36mm (corrected for body size [PSAX/BSA] 18to,21mm/m 2)—or fractional area change .33%to 40%By MRI:†Regional RV akinesia or dyskinesia or dyssynchronous RV contraction †and 1of the following:—Ratio of RV end-diastolic volume to BSA 100to ,110mL/m 2(male)or90to ,100mL/m 2(female)—or RV ejection fraction .40%to 45%II.Tissue characterization of wall Major†Fibrofatty replacement of myocardium on endomyocardial biopsy †Residual myocytes ,60%by morphometric analysis (or ,50%if estimated),with fibrous replacement of the RV free wall myocardium in 1sample,with or without fatty replacement of tissue on endomyocardial biopsyMinor†Residual myocytes 60%to 75%by morphometric analysis (or 50%to 65%if estimated),with fibrous replacement of the RV free wall myocardium in 1sample,with or without fatty replacement of tissue on endomyocardial biopsyIII.Repolarization abnormalities Major†Inverted T waves in right precordial leads (V 1,V 2,and V 3)or beyond in individuals .14years of age (in the absence of complete right bundle-branch block QRS 120ms)Minor†Inverted T waves in right precordial leads (V 2and V 3)(people age .12years,in absence of right bundle-branch block)†Inverted T waves in leads V 1and V 2in individuals .14years of age (in the absence of complete right bundle-branch block)or in V 4,V 5,or V 6†Inverted T waves in leads V 1,V 2,V 3,and V 4in individuals .14years of age in the presence of complete right bundle-branch blockContinuedF.I.Marcus et al .808at Peking University on March 6, 2011 Downloaded fromSince publication of the 1994Task Force guidelines,cardiovascu-lar evaluation of the relatives of ARVC/D index cases and,more recently,genotype–phenotype association studies have also high-lighted the shortcomings of the criteria.It is now recognized that LV involvement may occur early in the course of the diseasewith some frequency.4,41The criteria also lack sensitivity for the diagnosis of familial disease.Modifications of the original criteria have been proposed to facilitate clinical diagnosis in first-degree relatives who often have incomplete expression of the disease.42According to these recommendations,in the context of proven.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Table 1ContinuedOriginal task force criteriaRevised task force criteriaIV.Depolarization/conduction abnormalities Major†Epsilon waves or localized prolongation (.110ms)of the QRS complex in right precordial leads (V 1to V 3)†Epsilon wave (reproducible low-amplitude signals between end of QRS complex to onset of the T wave)in the right precordial leads (V 1to V 3)Minor†Late potentials (SAECG)†Late potentials by SAECG in 1of 3parameters in the absence of a QRS duration of 110ms on the standard ECG†Filtered QRS duration (fQRS) 114ms†Duration of terminal QRS ,40m V (low-amplitude signal duration) 38ms †Root-mean-square voltage of terminal 40ms 20m V†Terminal activation duration of QRS 55ms measured from the nadir of the S wave to the end of the QRS,including R 0,in V 1,V 2,or V 3,in the absence of complete right bundle-branch blockV.Arrhythmias Major†Nonsustained or sustained ventricular tachycardia of left bundle-branchmorphology with superior axis (negative or indeterminate QRS in leads II,III,and aVF and positive in lead aVL)Minor†Left bundle-branch block-type ventricular tachycardia (sustained and nonsustained)(ECG,Holter,exercise)†Frequent ventricular extrasystoles (.1000per 24hours)(Holter)†Nonsustained or sustained ventricular tachycardia of RV outflow configuration,left bundle-branch block morphology with inferior axis (positive QRS in leads II,III,and aVF and negative in lead aVL)or of unknown axis †.500ventricular extrasystoles per 24hours (Holter)VI.Family history Major†Familial disease confirmed at necropsy or surgery†ARVC/D confirmed in a first-degree relative who meets current Task Force criteria†ARVC/D confirmed pathologically at autopsy or surgery in a first-degree relative †Identification of a pathogenic mutation †categorized as associated or probably associated with ARVC/D in the patient under evaluation Minor†Family history of premature sudden death (,35years of age)due to suspected ARVC/D†Familial history (clinical diagnosis based on present criteria)†History of ARVC/D in a first-degree relative in whom it is not possible or practical to determine whether the family member meets current Task Force criteria †Premature sudden death (,35years of age)due to suspected ARVC/D in a first-degree relative†ARVC/D confirmed pathologically or by current Task Force Criteria in second-degree relativePLAX indicates parasternal long-axis view;RVOT,RV outflow tract;BSA,body surface area;PSAX,parasternal short-axis view;aVF,augmented voltage unipolar left foot lead;and aVL,augmented voltage unipolar left arm lead.Diagnostic terminology for original criteria:This diagnosis is fulfilled by the presence of 2major,or 1major plus 2minor criteria or 4minor criteria from different groups.Diagnostic terminology for revised criteria:definite diagnosis:2major or 1major and 2minor criteria or 4minor from different categories;borderline:1major and 1minor or 3minor criteria from different categories;possible:1major or 2minor criteria from different categories.*Hypokinesis is not included in this or subsequent definitions of RV regional wall motion abnormalities for the proposed modified criteria.†A pathogenic mutation is a DNA alteration associated with ARVC/D that alters or is expected to alter the encoded protein,is unobserved or rare in a large non-ARVC/D control population,and either alters or is predicted to alter the structure or function of the protein or has demonstrated linkage to the disease phenotype in a conclusive pedigree.Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia809at Peking University on March 6, 2011 Downloaded fromis based on the documentation of one of the following in a family member:(1)T-wave inversion in right precordial leads V1,V2,and V3inindividuals over the age of14years.(2)Late potentials by signal-averaged ECG(SAECG).(3)Ventricular tachycardia of left bundle-branch block mor-phology on ECG,Holter monitor,or during exercise testing or.200premature ventricular contractions in24hours. (4)Either mild global dilatation or reduction in RV ejection frac-tion with normal LV or mild segmental dilatation of the RV or regional RV hypokinesis.Revision of the diagnostic criteria is important to provide guidance on the role of emerging diagnostic modalities and to recognize advances in the genetics of ARVC/D.The criteria have been modi-fied to incorporate new knowledge and technology to improve diagnostic sensitivity,but with the important requisite of maintain-ing diagnostic specificity,and they include quantitative parameters for Task Force criteria,particularly for the imaging studies (Table1).The approach of classifying structural,histological, ECG,arrhythmic,and genetic features of the disease as major and minor criteria has been maintained.MethodsA limitation of the previous Task Force criteria was the reliance on subjective criteria for assessing ventricular structure and function and for evaluation of myocardial histology.In this modification of the Task Force criteria,quantitative criteria are proposed and abnormalities are defined on the basis of comparison with normal subject data(Table1).The data from108probands with newly diagnosed ARVC/D,age 12years,who were enrolled in the National Institutes of Health-supported Multidisciplinary Study of Right Ventricular Dysplasia,43were compared with those of normal subjects(online-only Data Supplement).The cri-teria were selected on the basis of analysis of sensitivity and speci-ficity from receiver operating characteristic curves.For analysis of each test[e.g.echocardiogram,magnetic resonance imaging (MRI)],proband data were excluded if that test was crucial for the diagnosis of the individual patient.This was done to eliminate bias in estimating the sensitivity and specificity of that particular test.In general,when determining the sensitivity and specificity of a new screening test,it is recommended that none of the screening test elements be used in making the primary diagnosis; this principle also holds when establishing diagnostic criteria. ResultsThere were44proband MRIs compared with462MRIs of normal subjects,69proband echocardiograms compared with450echo-cardiograms of normal subjects,69proband SAECGs compared with103SAECGs of normal subjects,and68proband Holters compared with398Holters of normal subjects.The minor criteria for echocardiography were selected where specificity and sensi-tivity are equal(sensitivity equals specificity)(Table2).The major criteria were selected as the value that yielded95%specificity.Sen-sitivity and specificity for the MRI criteria were made RV end-diastolic volume indexed to body surface area(size)andRV ejection fraction(function)simultaneously by using the OR logistical function.If either RV size or function was positive in con-junction with RV wall motion abnormality,then the subject wouldbe classified as having a major criterion for the MRI.The sensitivityof RV size alone or function alone ranged from41%to50%formajor criteria and31%to41%for minor criteria,with specificityof96%to100%.Using the OR logistical function improved the sensitivity of the MRI to79%to89%for major criteria and68%to78%for minor criteria.The original Task Force criteria list late potentials as a minor cri-terion.It has become common practice,though not based on evi-dence,to state that the SAECG is positive if2of the following3 parameters are abnormal:filtered QRS duration(fQRS),root-mean square voltage of the terminal40ms of the QRS,or durationof the terminal QRS signal,40m V.Analysis of each of the single parameters of the SAECG with late potentials by using a40-to250-Hzfilter had a sensitivity ranging from58%to60%,with aspecificity of94%to96%.Two of three parameters had a sensi-tivity of66%and specificity of95%,adding little advantage withregard to sensitivity and specifiing any one of the3 SAECG parameters had a sensitivity of74%and specificity of92%.A definitive diagnosis of ARVC/D is based on histological dem-onstration of transmuralfibrofatty replacement of RV myocardiumat biopsy(Figure2),necropsy,or surgery.5,44In most patients, however,assessment of transmural myocardium is not possible.In addition,diagnosis based on RV endomyocardial biopsy speci-mens is limited because the segmental nature of the disease causes false e of electroanatomic voltage mappingto identify pathological areas for biopsy sampling may improvethe yield.45RV free wall biopsy has a slight risk of perforation,but the more accessible interventricular septum rarely exhibits his-tological changes.Nevertheless,endomyocardial biopsy may ident-ify other conditions(e.g.myocarditis,sarcoidosis,endomyocardialfibrosis),and the recognition of myocyte loss withfibrous orfibro-fatty replacement can be a valuable diagnostic feature.46The identification of disease-causing genes has led to the recognition of a broader spectrum of disease expression within families,including individuals who have predominantly LV disease, manifest clinically by inferolateral T-wave changes,ventricular ectopy,or ventricular tachycardia with right bundle-branch block morphology and epicardial or midmyocardial late enhancementby MRI.4,7,38,39,41The importance of familial disease highlights arole for mutation analysis of probands with cascade screening of relatives that offers an alternative strategy to serial noninvasive car-diovascular evaluation of families.A positive diagnosis in a family member changes the probability of disease in an individual sus-pected of the disease to1:2from1:1000to1:5000.Thus,con-firmed disease in afirst degree relative is a major criterion for diagnosis.42DiscussionThe diagnosis of ARVC/D relies on the demonstration of struc-tural,functional,and electrophysiological abnormalities that are caused by or reflect the underlying histological changes.Technical advances in MRI and2-dimensional echocardiography haveat Peking University on March 6, 2011Downloaded fromimproved the capability to image the RV with reproducible measure-ments of volume and systolic function,which permits classification of severity and differentiation from normality 47(Table 2).Previous diag-nostic reliance on subjective assessment of RV wall thinning,wall motion abnormalities,and fatty infiltration of the myocardium byMRI has proven problematic.48,49Recognition of significant fatty involvement without concomitant fibrosis of the RV in normal indi-viduals renders this unique MRI capability of limited te enhancement on MRI permits myocardial tissue characterization in the LV.It can be difficult to be certain of late enhancement for..............................................................................................................................................................................................................................................................................................................................................................Table 2Sensitivity and specificity of proposed RV imaging criteria*ValueSensitivity,%Specificity,%EchocardiogramMajorPLAX RVOT (diastole)32mm 7595Corrected for body size (PLAX/BSA) 19mm/m2PSAX RVOT (diastole)36mm 6295Corrected for body size (PSAX/BSA) 21mm/m 2Fractional area change 33%5595MinorPLAX RVOT (diastole)29mm8787Corrected for body size (PLAX/BSA) 16to 18mm/m 2iPSAX RVOT (diastole)32mm8080Corrected for body size (PSAX/BSA) 18to 20mm/m 2Fractional area change 40%7676MRI †MajorRatio of RV end-diastolic volume to BSAMales 110mL/m 2Females 100mL/m 27690F or6898CRV ejection fraction 40%MinorRatio of RV end-diastolic volume to BSAMales 100mL/m 2Females 90mL/m 27985F or8997CRV ejection fraction45%Abbreviations as in Table 1.*All the major and minor criteria listed in this table are in addition to the requirement that regional wall motion abnormalities must also be present.†The sensitivity and specificity for males and females are the same as listed if,in addition to the stated wall motion criteria,there is either abnormal RV size or function or both.Figure 2Endomyocardial biopsy findings in a proband affected by a diffuse form of ARVC/D.All 3biopsy samples are from different regionsof the RV free wall.There is extensive fibrofatty tissue replacement with myocardial atrophy,which is a major criterion (i.e.residual myocytes ,60%by morphometric analysis or ,50%if estimated).Contributed by C.Basso,Padua,Italy.Diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia811at Peking University on March 6, 2011 Downloaded fromcharacterization of RV myocardium because of the thin wall of the RV and possible confusion with fat.50There also have been recent developments to quantify the extent of RV wall motion abnormalities by angiography with computer-based analysis,as well as to determine RV volumes.51,52In addition,commercial software is available to deter-mine RV volumes and ejection fraction.53The RV angiogram obtained in multiple views is considered to be a reliable imaging test to assess wall motion abnormalities but requires considerable experience.Standardized protocols for performance of these diag-nostic studies (ECG,SAECG,echocardiogram,RV angiogram,and MRI)are available on .Repolarization abnormalities are early and sensitive markers of disease expression in ARVC/D.T-wave inversion in V1,V2,and V3and beyond in individuals .14years of age who are otherwise healthy is observed in only 4%of healthy women and 1%of men.Therefore,it is reasonably specific in this population and con-sidered a major diagnostic abnormality in ARVC/D.54Depolariz-ation delay in right precordial leads is also common in ARVC/D.33,34Evaluation of the duration of terminal QRS activation (Figure 3)incorporates slurring of the S wave,as well as R 0,into a single measure of terminal activation duration.34Depolarization abnormalities cannot be evaluated in the presence of typical com-plete right bundle-branch block with terminal delay in leads I and V 6.However,T-wave inversion in V 1,V 2,V 3,and V 4is uncommon in patients with right bundle-branch block who do not have ARVC/D and is seen frequently in those who do have the disease.Con-ventional definitions are used for ventricular arrhythmias.An abnormal SAECG is based on time domain criteria with cutoffs generated from receiver operating characteristic curves.55,56The sensitivity and specificity of any one of the time domain criteria is similar to that of any 2or 3of these criteria;therefore,any one of the criteria is proposed as a criterion for this modality.The presence of left bundle-branch block ventricular tachycardia with an inferior axis (R wave positive in leads II and III and negative in lead aVL)is typical of focal RV outflow tract tachycardia.57Similar features may be seen in patients with ARVC/D but usually coexist with anterior T-wave inversion and ventricular arrhythmias of varying morphologies.The presence of ventricular ectopy increases with age,but .200ventricular premature beats in 24hours in an adult ,50years of age suggests underlying myo-cardial disease.58The revised criteria were applied post hoc to 108newly diag-nosed probands enrolled in the Multidisciplinary Study of Right Ventricular Dysplasia,a study supported by the National Institutes of Health.They had been carefully evaluated,including assessment of diagnostic tests by expert core laboratories.43Of the 73pro-bands with final classification as ‘affected’,71remain affected and 2were reclassified as borderline.The change from affected to bor-derline in the 2was due to the echocardiogram’s fulfilling only minor criteria in one and only mild hypokinesis in the angiogram of the other.Of the 28probands classified as borderline (met some but not all of the original Task Force criteria–i.e.1major and 1minor or 3minor),5remain borderline and 16were reclas-sified by the new criteria as affected.Seven became unaffected (did not meet the proposed modified Task Force criteria).Of 7pro-bands previously classified as unaffected,4remained unaffected,1became affected,and 2became borderline.Therefore,the effect of the revised criteria is to increase the sensitivity of the classification,primarily in probands previously classified as borderline.Nine of 28probands classified as borderline by original criteria had gene variants consistent with ARVC/D.The sensitivity of the revised criteria is not perfect,as exemplified by the observation that if the genetic criteria are ignored,the proposed criteria classi-fied 2as unaffected and 3remained borderline,and 4became affected.Including the proposed genetic criteria resulted in all 9being classified asaffected.Figure 3ECG from proband with T-wave inversion in V 1through V 4and prolongation of the terminal activation duration 55ms measuredfrom the nadir of the S wave to the end of the QRS complex in V 1.Contributed by M.G.P.J.Cox,Utrecht,The Netherlands.F.I.Marcus et al .812at Peking University on March 6, 2011 Downloaded from。