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have tm-scores higher than 0.5 -回复题目：探索高于0.5的TMscores引言：TMscores是一种用于比较蛋白质结构相似性的评价指标，其取值范围从0到1。
当TMscore大于0.5时，意味着两个蛋白质结构之间存在较高的相似性。
本文将一步一步地解释TMscores以及如何获得高于0.5的TMscores。
第一部分：什么是TMscores？TMscores是根据蛋白质结构之间的相似性来计算的，主要基于两个结构的平均重叠区域大小以及二者之间的距离差异。
较高的TMscore表明两个蛋白质结构的折叠方式相似度较高。
TMscores可以用于比较不同蛋白质序列或蛋白质家族内的结构相似性。
第二部分：如何计算TMscores？计算TMscores需要使用专门的软件和算法，例如TM-align或TM-score。
这些软件使用不同的方法来比较两个蛋白质结构的相似性。
一般而言，计算TMscores的步骤包括：1. 蛋白质结构的预处理：这包括去除水分子、离子和其他杂质，使蛋白质结构更加纯净。
2. 提取蛋白质结构的特征：这种特征可以是氨基酸的空间坐标、二面角等。
3. 对比两个蛋白质结构：通过比较两个蛋白质结构的特征，计算它们之间的相似性。
4. 计算TMscores：基于结构的相似性和重叠区域大小，计算TMscore 的值。
第三部分：如何获得高于0.5的TMscores？要获得高于0.5的TMscores，需要注意以下几点：1. 蛋白质质量的准确性：蛋白质结构的准确性对TMscores的计算结果有较大影响。
使用高分辨率的实验方法或准确的模型构建工具能提高蛋白质结构的准确性。
2. 结构对齐的方法：不同的结构比对方法可能会导致不同的TMscores。
选择合适的结构比对方法是获得高TMscores的关键。
3. 结构调整的方法：在计算TMscores之前，可能需要进行一些结构调整，例如对齐结构的中心化或规范化。
-1004-中华实验眼科杂志2020年12月第38卷第12期Chin J Exp Ophthalmol,December2020,Vol.38,No.12-实验研究-载药交联脱细胞角膜基质透镜的制备及体外药物缓释效果评价饶静1陈建苏2顾佳宁2陈晓3王译妮2刘永欢1普蔼君3周奇志31中南大学爱尔眼科学院,长沙410015；2爱尔眼科研究所,长沙410000；3重庆爱尔眼科医院400020通信作者：周奇志,Email:zhouqizhi6931@【摘要】目的评价载左氧氟沙星脱细胞角膜基质透镜的体外药物释放特点，并探讨1A3-二甲氨基)丙基二亚胺/N-羟基琥珀酰亚胺(EDC/NHS)交联对其载药的影响'方法收集重庆爱尔眼科医院屈光科在飞秒激光辅助的角膜小切口基质透镜取出术(SMILE)中获取的角膜基质透镜,采用高质量浓度氯化钠(Nt)联合核酸酶制备脱细胞角膜基质透镜'采用随机数字表法将脱细胞角膜基质透镜随机分为正常组、0.5%左氧氟沙星组&3%左氧氟沙星组和5%左氧氟沙星组，每组4个,正常组未进行任何处理，载药各组将脱细胞角膜基质透镜分别浸泡于质量分数0.5%、3%、5%左氧氟沙星溶液中3h进行载药实验0采用EDC与NHS5：1混合液对脱细胞角膜基质透镜进行交联,用随机数字表法将脱细胞角膜基质透镜随机分为非交联组、0.01mmol EDC组、0.05mmol EDC组和0.25mmol EDC组,按照分组将脱细胞角膜基质透镜浸入不同浓度EDC/NHS中交联4h,然后浸于3%左氧氟沙星溶液中进行载药实验0采用高效液相色谱法(HPLC)测定各组载药角膜基质透镜缓释的药物质量浓度；以光谱扫描法测定各组角膜基质透镜透光率;采用扫描电子显微镜观察各组脱细胞角膜基质透镜的表面超微结构'结果载药后1、7、14、21.,0.5%、3%、5%左氧氟沙星脱细胞角膜基质透镜释放的药物浓度总体比较差异有统计学意义(P<0.05)；0.01、0.05和0.25mmol EDC组释放的药物浓度均高于非交联组,差异均有统计学意义(均P<0.01),其中0.05mmol EDC组各时间点释放的药物质量浓度最高'所有交联组的药物缓释时间可达21d，随时间延长各组释放的药物质量浓度呈缓慢下降趋势，差异有统计学意义(P<0.05)0非交联组和正常组透镜平均透光率分别为(88.68±1,19)%和(91.55土1.16) %,差异无统计学意义(E〉0.05)；载药脱细胞角膜基质透镜的平均透光率较正常组下降,差异有统计学意义(P<0.05)o扫描电子显微镜观察结果显示,交联后透镜的胶原纤维间空隙缩小,纤维排列紧密,以0.25mmol EDC组最明显0结论EDC/NHS交联能提高脱细胞角膜基质透镜载药效果，可能与胶原纤维空隙缩小有关-载药交联脱细胞角膜基质透镜具有良好的体外药物缓释效果-【关键词】角膜基质透镜；药物缓释；脱细胞；交联；左氧氟沙星DOI:10.3760/115989-20190817-00353Preparation and drug release effect evaluation of drug-loaded cross-linked decellularized corneal stromallenticules!vitroRao Jing1,Chen Jiansu2,Gu Jianing2,Chen Xiao3,Wang Yini2, Liu Yonghuan1, Pu Aijun3,Zhou Qizhi31Aier School of Ophthalmology,Central South University,Changsha410015,China；2A ier Ophthalmology Institute,Changsha410000,China；3Chongqing Aies OpPthalmolofy Hospital,Choogqing400020,ChinaCorrespooding author：Zhoo Qizhi,Emaii lzhooqizhi6931@Abstract Objective To prepara a drug release system of drug-loaded cross-linked decellularized cerneatstromal lenticules and e valuate ite drug release characteristics i vitre.Methods Lenticules were obtained duringfemtosecond laser-assisted small incision lenticule extraction(SMILE)suraera in Chongqing Aier OphthalmologyHospitaL Decellularized corneae stromal lenticules were prepared using high concentration sodium chloride(Nad) eombiningnueeease.Thedeee e ueaaized eoaneaestaomaeeentieueesweaeaandomesdiaided into no ama eg aoup,0.5%levoeoxacin group,3%levoeoxacin group and5%levoeoxacin group,with4lenticules in each group.The lenticulesdid not reccivo any treatment in the normaO group,and drug-loading those were soaked in different doses oflevoeoxacin solution for three hourr according te grouping.In the crosslinking test,12decellularized cerneat stromatenticu esweeeeandom sdioided into non lc eo ssinking g eoup,0.01mmo)1l(3ldimethsamino)peopsimine(EDC)group,0.05mmol EDC group and0.25mmol EDC group.The lenticules for cross-linking were soaked in differentcententr of mixed solution of EDC with N-hydroxysuccinyS(NHS)for four hourr respectively accerding to grouping,中华实验眼科杂志2020年12月第38卷第12期Chin J Exp Ophthalmol,December2020,Vol.38,No.12-1005-and then in3%leveooxacin solution for three hours.Only3%leveooxacin solution soaking was carried in the noncrosslinking group.High peWormance liquid chromatooraphy(HPLC)was employed to detect the drug releaseconcentaation ootheaenticuaes,and spectaaascanningmethod waspeaooamed to measuaeaighttaansi t anceootheaenticuaes.Thesuaoaceuataastauctuaeoothedece a uaaaieed aenticu aes among di e aent c aoss-ainking g aoups was examinedand compaaed with scanningeaectaon micaoscope.Theuseoothehuman coaneaaaenticuaeswasappaoeed byan EthicsCommi t eeooChongqingAieaOphthaamoaogyHospitaa(No.2019012).Wai t en inooamed consentwasobtained oaomeach patient before surgew•Reselte The release cencentrations oS decellum.rized cerneat stroma lenticules weresignificantly different at1day,7,14,and21days among0.5%,3%,and5%levefloxacin group(P<0.05)or alsoamong the0.01mmol EDC,0.05mmol EDC,and0.25mmol EDC cross-linked groups(P<0.01).The drug releaseconcentaationsin0.05mmo)EDC gaoup we ae the highest at ea aious time points,and theaeeasetimeoothethaeecaoss-inked gaoups asted unti21daysaoteaaeeaseconcentaationsoodece)u aaieed coanea)staoma enticu es.The daugaeeaseconcentaationsin caoss-inked gaoupsand non-c aoss inking g aoup weaegaadua ydecined with thepaoongoS drug-loading time,showing a significant difference at different time points(E<0.05).The transmittance oS thelenticules was(88.68±1.19)%and(91.55±1.16)%in the non-crosslinking group and normal group,respectively,with no significant difference(E〉0.05).The averaae transmittance oS the lenticules was significantly reduced in thedrug-oaded groups ccmpared with the normal group(P<0.05).The smaller ccllaaen fiber veids and closely arrangedccllaaen fiberr were displayed in the cross-linking groups under the scanning electron microsccpe with the best effectin the0.25mmol EDC group.Conclusions EDC/NHS cross-linking can improve the drug-loading effect oSdeccllularized cerneat stromal lenticules probably by lessening ccllaaen fiber veids.The drug-loaded cross-linkeddece e u eaaieed co anea est aoma eeenticu ees ha ee a good daugaeeeasee o e ct in eiteo.Key words Corneal stromal lenticules；Drug sustained release；Deccllularization；Cross-linking；LeveOoxacinDOI：10.3760/115989-20190817-00353眼表疾病治疗的常用给药方式为滴眼液的局部点眼，但存在药物局部保留时间短、角膜渗透性差、生物利用度低、患者舒适度及依从性差等缺点’作为新兴的给药方式，药物缓释系统以其可延长药物在局部组织中的作用时间、减少局部点药频次而受到临床关注［，目前眼表药物缓释系统的研究主要有载药羊膜和载药角膜接触镜的研发［3宀。
Journal of Mathematical Medicine Vol.28No.12015收稿日期：2014-08-13通讯作者:李晓梅△基金项目:国家自然科学基金（81060021）自由基是人体新陈代谢的中间产物，通过氧化其他分子从而破坏细胞结构，影响机体的生理功能。
胶原蛋白现已证实具有抗氧化活性，适当摄入可以降低体内自由基的水平，帮助机体抵抗疾病[1]。
鼠尾胶原的主要成分是I 型胶原蛋白，自提取以来主要用于促进细胞贴壁和组织工程中支架结构的构建。
近年来随着对鼠尾胶原的研究发现，鼠尾胶对细胞的生长分化、组织的愈合以及促进凝血等发挥重要的作用[2,3]。
虽然目前关于胶原蛋白的抗氧化作用已有报道，但主要是关于食物和美容方面，而在细胞水平的研究甚少，在此我们探索鼠尾胶原在体外培养心肌细胞氧化应激损伤中是否能发挥保护作用。
本实验通过用不同浓度的H 2O 2刺激体外培养的乳鼠心肌细胞来建立氧化损伤模型，利用鼠尾胶原预处理培养皿，通过检测心肌细胞存活率、凋亡率以及Bax 、Bcl-2的表达来验证鼠尾胶原对体外心肌细胞的氧化损伤具有保护作用。
1材料与方法1.1实验动物：新生1~3天SD 大鼠乳鼠，雌雄不限，由新疆医科大学实验动物中心提供。
实验方案获得新疆医科大学实验动物伦理委员会批准。
1.2主要仪器与试剂：多功能酶标仪（Thermo ），倒置荧光显微镜（LEICA ），蛋白电泳系统（Invitrogen ）。
胰蛋白酶、II 型胶原酶、溴脱氧尿甘、青-链霉素、3%H 2O 2均由美国Sigma 公司提供，DMEM 培养基、胎牛血清均为美国Gibco 公司产品。
Annexin-V试剂盒（Roche ），Bax 、Bcl-2单克隆抗体（Abcam ）。
1.3鼠尾胶原的制备和铺板：取大鼠尾巴洗净，75%酒精浸泡5min 后将尾巴剪开、去掉皮毛，并剪成小段，抽出银色的尾键。
将尾腱剪断置于平皿中，用生理盐水浸泡后吸去生理盐水，将尾腱称重。
等离子体增强CVD法沉积的微晶硅薄膜的微结构研究(英文)陈永生;杨仕娥;卢景霄;郜小勇;张宇翔;王海燕;李瑞
【期刊名称】《人工晶体学报》
【年(卷),期】2005(34)4
【摘要】本文系统研究了PECVD法沉积μc-Si薄膜中衬低温度、氢气稀释率和射频功率等参数对μc-Si薄膜结构特性的影响。
表明:随着衬低温度的增加、氢气稀释率的增大、射频功率的提高,薄膜的晶化率增大。
沉积薄膜的晶化率最大可达80%,表面粗糙度大约为30nm。
通过对反应过程中的能量变化进行了分析,得到反应为放热反应,且非晶结构对沉积参数比较敏感。
【总页数】7页(P753-759)
【关键词】微晶硅薄膜;晶化率;等离子体增强化学气相沉积
【作者】陈永生;杨仕娥;卢景霄;郜小勇;张宇翔;王海燕;李瑞
【作者单位】郑州大学物理系
【正文语种】中文
【中图分类】O484.1
【相关文献】
1.沉积速率对甚高频等离子体增强化学气相沉积制备微晶硅薄膜生长标度行为的影响 [J], 丁艳丽;朱志立;谷锦华;史新伟;杨仕娥;郜小勇;陈永生;卢景霄
2.HW-MWECR-CVD法制备氢化微晶硅薄膜及其微结构研究 [J], 刘国汉;丁毅;朱秀红;陈光华;贺德衍
3.微波电子回旋共振等离子体增强化学气相沉积法沉积氟化非晶碳薄膜的研究 [J], 叶超;宁兆元;程珊华;康健
4.热丝辅助MW ECR CVD技术高速沉积高质量氢化非晶硅薄膜(英文) [J], 周怀恩;陈光华;朱秀红;阴生毅;胡跃辉
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经皮穿刺椎间盘髓核射频靶点消融联合臭氧注射治疗腰椎间盘突出症疗效观察刘锋，温建生，陈明凤，寇艳艳北京中医药大学孙思邈医院周围血管病科，陕西铜川727106【摘要】目的观察经皮穿刺椎间盘髓核射频靶点消融联合臭氧注射治疗腰椎间盘突出症的疗效。
方法选取2020年5月至2022年5月期间北京中医药大学孙思邈医院收治的102例腰椎间盘突出症患者作为研究对象，按照随机数表法分为研究组和对照组各51例。
对照组患者给予臭氧注射治疗，研究组患者则给予经皮穿刺椎间盘髓核射频靶点消融联合臭氧注射治疗。
比较两组患者的术后优良率、术前及术后10d 的视觉模拟疼痛(V AS)评分、日本矫形外科协会(JOA)评分及炎症因子白细胞介素-6(IL -6)、白细胞介素-8(IL -8)、肿瘤坏死因子-α(TNF -α)水平。
结果研究组患者的术后优良率为96.08%，明显高于对照组的82.35%，差异具有统计学意义(P <0.05)；术前，两组患者的V AS 评分、JOA 评分比较差异均无统计学意义(P >0.05)，术后10d ，两组患者的V AS 评分均降低，且研究组患者的V AS 评分为(1.35±0.16)分，明显低于对照组的(2.46±0.72)分，但两组患者的JOA 评分较术前均升高，且研究组患者的JOA 评分为(21.46±4.06)分，明显高于对照组的(15.43±3.84)分，差异均具有统计学意义(P <0.05)；术前，两组患者的IL -6、IL -8、TNF -α水平比较差异均无统计学意义(P >0.05)，术后10d ，两组患者的IL -6、IL -8、TNF -α水平均降低，且研究组患者的IL -6、IL -8、TNF -α水平分别为(93.54±6.48)pg/mL 、(111.32±30.85)μg/L 、(95.18±13.48)pg/mL ，明显低于对照组的(120.48±7.62)pg/mL 、(132.68±31.46)μg/L 、(124.28±10.28)pg/mL ，差异均具有统计学意义(P <0.05)。
专利名称：中药诱导骨髓间质细胞分化为神经元样细胞的方法专利类型：发明专利
发明人：李海标,撒亚莲
申请号：CN02134983.5
申请日：20021018
公开号：CN1410530A
公开日：
20030416
专利内容由知识产权出版社提供
摘要：本发明涉及一种骨髓间质细胞的定向分化技术。
本技术包括bFGF预诱导和定向诱导MSC向神经元样细胞分化两个步骤：(1)bFGF预诱导：用含有胚牛血清和bFGF的低糖DMEM培养；(2)定向诱导MSC向神经元样细胞分化：用含有中药成分的无血清低糖DMEM中诱导。
本发明具有高效、安全性好、来源丰富经济等优点。
申请人：中山大学
地址：510275 广东省广州市新港西路135号
国籍：CN
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聚多巴胺修饰载姜黄素介孔二氧化硅纳米粒的研究
王小宁;任佩佩;赵阳光;张湛睿;闫梦茹
【期刊名称】《中国药师》
【年(卷),期】2024(27)4
【摘要】目的制备聚多巴胺(PDA)修饰的载姜黄素(CUR)介孔二氧化硅纳米粒(MSN),并对其进行药剂学性质、体外释药及体外抗肿瘤活性研究。
方法以模板法合成介孔二氧化硅纳米粒,对其表面进行PDA修饰,考察纳米粒的药剂学性质,研究载药制剂的pH响应性释药,评价载体的生物相容性和载药制剂的体外细胞生长抑制率,考察肿瘤细胞对载药制剂的摄取。
结果 MSN粒径均一,经PDA修饰
后,CUR@MSN-PDA体外释药具有显著的pH响应性;生物相容性结果表明,各载体材料与MDA-MB-231细胞共培养24 h后,细胞存活率均在85%以上;体外肿瘤细胞生长抑制率实验结果表明,CUR@MSN-PDA对肿瘤细胞的生长抑制率显著高于CUR@MSN,细胞摄取结果表明,CUR@MSN-PDA在细胞内的荧光强度显著强于CUR@MSN。
结论构建的纳米载体具有显著的pH响应性和较强的抗肿瘤活性,为CUR的药物递送提供了理论依据。
【总页数】8页(P580-587)
【作者】王小宁;任佩佩;赵阳光;张湛睿;闫梦茹
【作者单位】西安医学院药学院
【正文语种】中文
【中图分类】R73
【相关文献】
1.聚多巴胺修饰介孔二氧化硅SBA-15及体外生物活性研究
2.姜黄素介孔二氧化硅纳米粒载药系统的制备及其载药性能
3.OX26/ApoE共修饰的载小檗碱介孔二氧化硅纳米粒药动学研究
4.Angiopep-2修饰载神经毒素介孔二氧化硅脂质囊纳米粒的制备及其体内外评价
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迷迭香提取物对亚急性衰老模型小鼠的抗衰老作用
王虹;刘红梅
【期刊名称】《中药药理与临床》
【年(卷),期】2008(024)003
【摘要】目的:观察迷迭香提取物对D-半乳糖所致亚急性衰老模型小鼠的抗衰老作用.方法:雄性小鼠连续6周皮下注射D-半乳糖1 mg/g*d制备小鼠衰老模型.造模同时以迷迭香提取物灌胃,检测血清和脑中超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量;以及进行耐缺氧实验.结果:衰老模型对照组血清、脑中SOD 活力明显降低,MDA含量明显增高.与衰老模型对照组相比,迷迭香各剂量组的SOD 活力明显提高,MDA含量明显降低;且各剂量组都能延长小鼠耐缺氧时间.结论:迷迭香提取物能清除自由基,具有抗衰老作用.
【总页数】3页(P52-54)
【作者】王虹;刘红梅
【作者单位】山东农业大学生命科学学院,泰安,271018;泰山医学院化学与化学工程学院,泰安,271016;山东农业大学生命科学学院,泰安,271018
【正文语种】中文
【中图分类】R2
【相关文献】
1.新疆紫草萘醌类色素对小鼠D-半乳糖亚急性衰老模型的抗衰老作用研究 [J], 许今博;贺金华;买尔旦·马合木提
2.针灸对亚急性衰老模型小鼠皮肤的抗衰老作用研究 [J], 王彩霞
3.二至丸对亚急性衰老模型小鼠抗衰老作用的实验研究 [J], 王淑梅;王灿岭
4.凝结芽孢杆菌TBC169株对亚急性衰老模型小鼠的抗衰老作用 [J], 刘锋;张娟娟;张海霞;马庆英;李雄彪;崔云龙
5.东兰墨米对亚急性衰老模型小鼠的抗衰老作用 [J], 黄俊杰;赵善民;晋玲;黄丽娟;何显教;韦启后
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a rXiv:as tr o-ph/49369v115Se p24Impact of Gravitational Lensing on Cosmology Proceedings IAU Symposium No.225,2004Mellier,Y.&Meylan,G.eds.c 2004International Astronomical Union DOI:00.0000/X000000000000000X Predicting Substructure in CDM Haloes James E.Taylor 1†,Arif Babul 21Denys Wilkinson Building,1Keble Road,Oxford OX13RH,United Kingdom email:jet@ 2Elliott Building,3800Finnerty Road,Victoria,BC,V8P 1A1,Canada email:babul@uvic.ca Abstract.Observations of multiple-image gravitational lens systems suggest that the projected mass distributions of galaxy haloes may contain substantial inhomogeneities.The fraction of the halo mass in dense substructure is still highly uncertain,but could be as large as a few percent.While halo substructure is seen in numerical simulations of CDM haloes,little of this substructure survives in the innermost regions of haloes,and thus the observational claims for substructure at small projected radii are slightly surprising.There is evidence,however,that even the highest-resolution simulations published to-date are still limited by numerical effects that heat and disrupt substructure artificially in high-density regions.By comparing numerical and semi-analytic (SA)models of halo substructure,we show that current simulations probably underestimate the mass fraction in substructure at small projected radii,by a factor of at least 2–3.We discuss the prospects for using lensing observations as a fundamental test of the nature of dark matter.2Taylor&Babulpotential(Evans&Witt2003).Currently there still seems good evidence for genuineanomalies in a few systems(Moustakas&Metcalf2003;Metcalf et al.2004;Metcalf these proceedings),suggesting substructure in the projected mass distribution at thelevel of a few percent,but continued observations at many different wavelengths willbe required to disentangle the effects of substructure from microlensing,scintillation or other phenomena.The observational effort is worthwhile,however,as it may provide thefirst hard evidence to justify one of the main assumptions of our current cosmological model,the cold,collisionless nature of dark matter.2.A new approach to modelling CDM haloesWhatever the status of the substructure problem observationally,it is not clear thatthere is a robust theoretical prediction with which to compare the lensing results.Dark matter haloes form through the gravitational collapse of diffuse dark matter,as well as thehierarchical merging of smaller haloes.The process is sufficiently non-linear that most of our understanding of it comes from numerical simulations.The strong lensing anomaliesdepend on the net mass fraction in relatively low-mass substructure(105M⊙–107M⊙), projected on the central few kiloparsecs of galaxy haloes.This is close to,or beyond, the formal resolution limit of most current simulations,and even in those simulationsthat can resolve structures on this scale,serious doubts remain as to the completeness ofthe results in the innermost parts of the halo.Thus,while simulations currently predict less central substructure than inferred from observations,this may be partly due to their limited resolution.To study halo substructure on smaller scales or very close to the centre of the halo,wehave developed an alternative,semi-analytic model(Taylor&Babul2004;Taylor&Babulin preparation).This model includes several distinct components.First,merger histories for a large number of individual haloes are generated randomly,using Press-Schechter statistics and the merger-tree algorithm of Somerville and Kolatt(1999),together with a correction for higher-order substructure developed in Taylor&Babul(2004).Each merging subhalo is then placed on a random orbit starting at the virial radius of the main system,and evolved using the analytic model of satellite dynamics described in Taylor &Babul(2001),experiencing orbital decay due to dynamical friction,and heating and stripping due to tidal forces.The properties of the main system change dynamically over time,and the formation of a galaxy can also be modelled schematically,as described in Taylor&Babul(2003),further modifying the central mass distribution.Overall,this model provides a computationally efficient way of simulating the hier-archical assembly of galaxy or cluster haloes,and the evolution of their substructure. Because it performs only a few calculations per lump of dark matter(or‘subhalo’)merg-ing with the main system it can be used to track the evolution of many thousands of subhaloes in a typical system,providing complete information about halo substructure down to masses around105–106M⊙.3.Results:The outer haloTo test the accuracy of the SA model,we have used it to generate a large set of galaxy haloes and compared their substructure to the substructure found in a set of high-resolution simulations of halo formation by Ghigna et al.(1998,2000)and Moore et al.(1999a,1999b).These include the galaxy-mass haloes‘Andromeda’and the‘Milky Way’(the‘Local Group’–Moore et al.1999b)and cluster-mass haloes‘Coma’,‘Virgo I’and‘Virgo II’(Virgo IIa and b are two different outputs from the same simulation).Substructure in CDM Haloes3Figure1.(Left)The cumulative mass function predicted by the SA model in the outer parts of the halo.The thick lines show the average result for a hundred SCDM merger trees at z=0. The thin solid lines show the1-σvariance for this set.The dashed and dotted lines are the normalised cumulative mass functions measured in three high-resolution simulations(dashed lines–Virgo IIa and IIb;dotted lines–Coma).The vertical lines indicate the resolution limit of the SA trees(solid)and the32-particle mass limits of the simulations(dotted and dashed). (Right)The distribution of subhaloes as a function of their mass and of their peak velocity,in the SA model(left-hand plots)and the simulations(right-hand plots;values are scaled to the SA halo mass and velocity).Each was resolved with∼106particles of more,and with a softening length of less than 1%of the virial radius.The left-hand plot infigure1compares the cumulative distribution of subhalo masses in the outer regions of the SA haloes(thick solid line)with the simulations(dashed ordotted lines).The masses have been scaled to the mass of the parent halo in the SA model,1.6×1012M⊙,for comparison.Overall wefind an excellent match in the outer regions of the halo.The simulations have an average amplitude about20%lower than theSA average,but this is only1–2times the halo-to-halo scatter(thin solid lines).We note that this agreement is achieved without adjusting any free parameters–the parameters in the semi-analytic model have all beenfixed previously by other considerations,as discussed in paper Taylor&Babul(2004).The right-hand plot infigure1shows that the internal structure of subhaloes is also very similar.The peak circular velocity of each system is plotted versus its mass,for the SA models(left-hand plots)and the numerical models(right-hand plots).Values are scaled as infigure1.The effects of softening and shot noise in the number of particles within the peak radius of each subhalo have been added to SA results,since these effects are present in the numerical data.With this correction,wefind very good agreement between the distributions of subhalo properties.4.Results:The inner haloIn the inner halo,on the other hand,the SA model run with the same parameters as above predicts2–3times more substructure than is seen in the numerical simulations. Moreover,the distribution of substructure is much more centrally concentrated than in4Taylor&BabulFigure2.Top panels:The number density of subhaloes in the SA haloes(upper solid lines) and in three simulations(connected points with error bars).To avoid incompleteness,the results are cut at the equivalent of5×107M⊙.In each case the density is relative to the mean within the virial radius.The dashed line shows the density profile of the main halo,normalised to the mean within the virial radius.Bottom panels:The cumulative number of subhaloes vs.radius, normalised to the number within the virial radius,for the same mass cuts as in the top panel. The dashed lines show the mass of the main halo interior to a given radius,normalised to the mass within the virial radius.The dotted lines in the left-hand panels show the results of ignoring highly stripped systems;the dotted lines in the right-hand panels show the results of ignoring old systems.the simulations.Figure2compares the radial distribution of subhaloes in the SA models (solid and dotted lines)and three simulations(dashed or dot-dashed lines+data points). The smooth dashed curve shows the overall mass distribution of the parent halo.While both SA and numerical subhaloes are antibiased with respect to the background mass distribution,the SA model predicts a central density of substructure3–4times higher than the numerical value.Removing highly-stripped systems(left-hand panel)does not affect this result very strongly,but removing old systems(right-hand panel)does.Thus the SA model predicts the existence of an extra population of old systems,deep in the centre of the halo.The importance of these results for lensing detections of halo substructure is illustrated infigure3.This compares the projected mass function within various radii around a galaxy halo(top panels),and the fraction of the projected surface density in substruc-ture(bottom panels),for the SA model and the highest-resolution simulation(solid and dashed lines respectively).The offset of∼2between the two,when averaged over large projected radii(leftmost panel),grows to roughly an order of magnitude at small pro-jected radii(3rd and4th panels).5.Summary and future prospectsWhen observations can reliably determine the clustering of dark matter on subgalactic scales,they will shed light on a number of important questions in fundamental physics. The nature and amplitude of small-scale CDM structure depends on the spectrum ofSubstructure in CDM Haloes5Figure3.(Top panel)Cumulative mass functions for subhaloes within some projected radius R p,for the SA model(solid lines)and Virgo IIa(dashed lines).(Bottom Panel)The fraction of the projected mass within R p contained in subhaloes of mass M or larger.The numerical results are the average over three different projections.Vertical lines indicate the resolution limit of the merger tree(solid)and the32-particle mass limits of the simulation(dashed). perturbations generated towards the end of inflation,which in turn depends on the pri-mordial spectral index,the shape of inflationary potential,and the physics of reheating. The subsequent growth of these perturbations also depends on the equation of state of the universe at the quark-hadron transition and at nucleosynthesis.Finally,the evolu-tion of small-scale structure at late times is a sensitive test of dark matter physics,such as interactions or annihilation.These small-scale properties will also have an important effect on the growth of visible structure,especially at very high redshift during the epoch of reionization.To tap the potential of recently developed methods for detecting substructure in strongly lensed systems,we need robust predictions for the behaviour of dark matter on very small scales,at very high densities,over cosmological timescales.Achieving this goal remains a challenge for current numerical simulations of structure formation.We have presented initial results from a semi-analytic model which uses halo merger trees and satellite dynamics to model the properties of substructure within dark matter haloes. Without any adjustment of free parameters,this model matches the results of high-resolution simulations very closely in the outer parts of haloes,where the simulations are most likely to be accurate.In the inner parts,however,it predicts central densities of substructure3–4times higher than those found in simulations.This may help explain the very high levels of substructure inferred from recent lensing observations. AcknowledgementsThe authors wish to thank E.Hayashi,S.Ghigna,B.Moore,J.Navarro and T.Quinn for providing the substructure data from their simulations.JET gratefully acknowledges support from PPARC UK.AB gratefully acknowledges support from NSERC Canada, through the Discovery and the Collaborative Research Opportunities(CRO)programs.6Taylor&BabulReferencesBlandford,R.D.&Jaroszynski,M.1981,ApJ246,1.Bradaˇc,M.,Schneider,P.,Steinmetz,M.,Lombardi,M.,King,L.J.,&Porcas,R.2002,A&Ap 388,373.Chiba,M.2002,ApJ565,17.Chen,J.,Kravtsov,A.V.,&Keeton,C.R.2003,ApJ592,24.Dalal,N.&Kochanek,C.S.2002,ApJ572,25.Eke,V.R.,Navarro,J.F.,&Steinmetz,M.2001,ApJ554,114.Evans,N.W.&Witt,H.J.2003,MNRAS345,1351.Ghigna,S.,Moore,B.,Governato,F.,Lake,G.,Quinn,T.,&Stadel,J.1998,MNRAS300,146. Ghigna,S.,Moore,B.,Governato,F.,Lake,G.,Quinn,T.,&Stadel,J.2000,ApJ544,616. 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Moustakas,L.A.&Metcalf,R.B.2003,MNRAS339,607.Press,W.H.&Gunn,J.E.1973,ApJ185,397.Schechter,P.L.&Wambsganss,J.2002,ApJ580,685.Somerville R.S.,Kolatt T.S.1999,MNRAS305,1.Spergel,D.N.et al.2003,ApJS148,175.Taylor,J.E.&Babul,A.2001,ApJ559,716.Taylor,J.E.&Babul,A.2003,Ap&SS284,405.Taylor,J.E.&Babul,A.2004,MNRAS348,811.Wambsganss,J.&Paczynski,B.1992,ApJL397,L1.DiscussionL.King:If you take your predicted substructure into account,will it explain the obser-vations?J.Taylor:Yes,or at least it almost will.The status of the observations is a bit unclear, but in the few systems were we do have strong evidence for substructure,the inferred level is high–within a few percent of the virial radius,a few percent of the projected mass density appears to be in substructure.This is at least ten times more than the simulations predict,but would be close to or just above the level the SA model predicts. The SA model also predicts a factor of3variation from one system to the next,however, so we really need to observe more systems.。
