{"currentpage":1,"firstResult":0,"maxresult":10,"pagecode":5,"pageindex":{"endPagecode":5,"startPagecode":1},"records":[{"abstractinfo":"近年来,为了提高药物载体的<span style=\"color:red\">靶向</span>性,国内外进行了广泛研究,<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>给药系统已成为给药系统研究的热点.主要介绍了<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>给药系统的机理、重要性及几种典型的<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>制剂,并对<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>药物载体:脂质体、毫微粒、乳剂、微泡的优缺点进行了详细的分析,提出了<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>制剂的发展趋势和前景.","authors":[{"authorName":"逯敏飞","id":"b6a4ee55-cecc-4fe6-9f81-3b0af308ff16","originalAuthorName":"逯敏飞"},{"authorName":"程永清","id":"35c86fdb-7385-49f0-bab3-0ea5a6b74179","originalAuthorName":"程永清"},{"authorName":"李丽君","id":"b3f2ffa7-6934-4620-bbd2-45a41adf530f","originalAuthorName":"李丽君"},{"authorName":"伍建军","id":"6ba9e99d-c120-4e5c-92c0-c7553889fd3c","originalAuthorName":"伍建军"}],"doi":"","fpage":"108","id":"80b1fa3a-8ea1-4d5e-ab81-d7aeeccb3fbb","issue":"9","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"9f39f7bc-0957-4a82-8462-ea5b807f61d2","keyword":"药物载体","originalKeyword":"药物载体"},{"id":"cd98c23a-470a-4709-8465-ecf22da66d6f","keyword":"<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>","originalKeyword":"被动靶向"},{"id":"92524a81-c39c-48a9-b310-43d8ac1125f1","keyword":"脂质体","originalKeyword":"脂质体"},{"id":"ef04e705-d40c-4029-9c43-adef4ddb6758","keyword":"毫微粒","originalKeyword":"毫微粒"},{"id":"370a66f0-85ea-4fbf-a0d1-53ee9bfb57a8","keyword":"乳剂","originalKeyword":"乳剂"},{"id":"43f65461-afc8-49af-82d5-6d3735e63e3e","keyword":"微泡","originalKeyword":"微泡"}],"language":"zh","publisherId":"cldb200509031","title":"<span style=\"color:red\">被动</span><span style=\"color:red\">靶向</span>药物载体的研究进展","volume":"19","year":"2005"},{"abstractinfo":"基于磁性纳米材料的肿瘤<span style=\"color:red\">靶向</span>磁感应热疗是近年来发展较快的一种肿瘤治疗手段，因其疗效确切、安全性高、副作用少，故可广泛用于临床肿瘤的治疗。但是，如何实现经静脉<span style=\"color:red\">被动</span>或主动<span style=\"color:red\">靶向</span>磁感应热疗并进一步提升治疗效果面临着重大挑战，这需要进一步提升磁性纳米颗粒的单分散性和交流磁热效应，增加靶组织或靶细胞累积、联合多靶点、多机制协同杀灭肿瘤细胞，聚焦磁感应加热以及依赖于多模成像的精确引导等，其中蕴藏的基础科学问题和关键核心技术急需突破。在介绍热疗用高性能磁性纳米材料的制备及表面修饰研究概况的基础上，对肿瘤<span style=\"color:red\">靶向</span>磁感应热疗当前的研究进展与技术发展的关键点进行探讨，阐述了其优点和需要解决的问题，并对其未来的发展前景做了展望。","authors":[{"authorName":"谢俊","id":"9be07c7e-1069-4c46-95bd-7c81a4ff82c9","originalAuthorName":"谢俊"},{"authorName":"陈玲","id":"2c8b4baa-0a21-4d89-8b77-29502ba9b1b4","originalAuthorName":"陈玲"},{"authorName":"严长志","id":"e2dd1799-135d-4bc8-8bc7-6c7e431408f5","originalAuthorName":"严长志"},{"authorName":"杨文清","id":"338d8a63-8e00-4393-8d09-4630c67fe9d2","originalAuthorName":"杨文清"},{"authorName":"张宇","id":"533ba534-2088-400c-94dc-5c8dfb19d06f","originalAuthorName":"张宇"},{"authorName":"顾宁","id":"e66a9c69-7b0f-4815-bd9b-2f2bcc1bacf6","originalAuthorName":"顾宁"}],"doi":"10.7502/j.issn.1674-3962.2016.08.01","fpage":"561","id":"f96fa7dc-959c-40af-96a3-74922127c912","issue":"8","journal":{"abbrevTitle":"ZGCLJZ","coverImgSrc":"journal/img/cover/中国材料进展.jpg","id":"80","issnPpub":"1674-3962","publisherId":"ZGCLJZ","title":"中国材料进展"},"keywords":[{"id":"acf270cf-5b93-42fa-b26d-8a3e13bed7ac","keyword":"磁性纳米材料","originalKeyword":"磁性纳米材料"},{"id":"a71434de-6f20-4fdd-86ed-b0320e559053","keyword":"<span style=\"color:red\">靶向</span>磁感应热疗","originalKeyword":"靶向磁感应热疗"},{"id":"c7f6af1f-1421-476a-a0c6-e02353363dc6","keyword":"疗效","originalKeyword":"疗效"},{"id":"b8ad1559-0ce4-48b1-870c-197c6c370dcc","keyword":"制备","originalKeyword":"制备"},{"id":"773c4ea6-6184-4c02-b946-4cd805543174","keyword":"表面修饰","originalKeyword":"表面修饰"}],"language":"zh","publisherId":"zgcljz201608001","title":"肿瘤<span style=\"color:red\">靶向</span>热疗用磁性纳米材料","volume":"35","year":"2016"},{"abstractinfo":"纳米磁<span style=\"color:red\">靶向</span>复合材料将纳米技术和磁<span style=\"color:red\">靶向</span>技术有机结合起来,借助纳米磁性材料的奇异特性,在肿瘤的磁<span style=\"color:red\">靶向</span>治疗领域具有很大的应用潜力而备受关注.介绍了纳米磁<span style=\"color:red\">靶向</span>复合材料的组成、制备及应用于肿瘤磁<span style=\"color:red\">靶向</span>治疗中的研究进展,并对其发展前景进行了展望.","authors":[{"authorName":"秦润华","id":"3713133b-210e-4691-8e44-356041ae81a0","originalAuthorName":"秦润华"},{"authorName":"姜炜","id":"f9b9f1ae-7135-4a88-b1f4-737d252a90f4","originalAuthorName":"姜炜"},{"authorName":"刘宏英","id":"a2f340af-6719-44e0-8577-b8ea4c481c95","originalAuthorName":"刘宏英"},{"authorName":"李凤生","id":"6a2101da-6089-4d79-b58e-15b05262592c","originalAuthorName":"李凤生"}],"doi":"","fpage":"44","id":"932f65eb-106d-4a5e-82c4-12e0cc59855d","issue":"9","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"8d75fc7d-4b98-431c-a17e-57475de6d052","keyword":"纳米","originalKeyword":"纳米"},{"id":"c34e70db-4f15-4686-97cb-34323958de18","keyword":"磁<span style=\"color:red\">靶向</span>","originalKeyword":"磁靶向"},{"id":"103948fb-46c9-4af8-a670-d22e1eaf94c9","keyword":"复合材料","originalKeyword":"复合材料"}],"language":"zh","publisherId":"cldb200709012","title":"纳米磁<span style=\"color:red\">靶向</span>复合材料的研究进照","volume":"21","year":"2007"},{"abstractinfo":"通过合理改性来调控淀粉的消化性能,使其具有不被上消化道消化、但能够被结肠微生物酵解的特性,则可用作口服结肠<span style=\"color:red\">靶向</span>药物控释载体.综述了淀粉的结构、消化特性、影响淀粉消化特性的因素及其在口服结肠<span style=\"color:red\">靶向</span>药物控释载体中的应用前景.","authors":[{"authorName":"陈玲","id":"c4705f1b-7259-4dae-9c39-45456d6a55d1","originalAuthorName":"陈玲"},{"authorName":"黄嫣然","id":"d88be38c-b04b-41ff-a96c-51eac1ff4c16","originalAuthorName":"黄嫣然"},{"authorName":"李晓玺","id":"2ee958ee-8265-40fe-a620-fd1e0cf02e4c","originalAuthorName":"李晓玺"}],"doi":"","fpage":"116","id":"3ae71693-bc33-4201-adc9-2ee0ba896c2a","issue":"2","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"06821090-169c-415b-aaf6-7eaecd83b5b4","keyword":"淀粉","originalKeyword":"淀粉"},{"id":"d44b1123-4b78-41ee-ad97-a7267b7d8a60","keyword":"抗消化淀粉","originalKeyword":"抗消化淀粉"},{"id":"82b9900f-dc48-4398-8ffc-428a43a54845","keyword":"口服结肠<span style=\"color:red\">靶向</span>","originalKeyword":"口服结肠靶向"},{"id":"df633e95-0f84-4e34-ab7b-be014d5aff7c","keyword":"药物载体","originalKeyword":"药物载体"}],"language":"zh","publisherId":"cldb200702030","title":"淀粉基口服结肠<span style=\"color:red\">靶向</span>给药控释载体","volume":"21","year":"2007"},{"abstractinfo":"综述了以叶酸(Folate)为<span style=\"color:red\">靶向</span>配体,聚酰胺-胺(PAMAM)为药物载体,通过叶酸受体的介导作用,实现主动<span style=\"color:red\">靶向</span>药物输送的研究进展;概括总结了PAMAM偶联叶酸<span style=\"color:red\">靶向</span>给药系统偶联药物的主要方法,并简要概括了PAMAM偶联叶酸<span style=\"color:red\">靶向</span>给药系统在肿瘤治疗方面及其他医学方向的研究.","authors":[{"authorName":"徐秀","id":"b0cbb082-f48b-4db6-a88e-7fc7c238eaa5","originalAuthorName":"徐秀"},{"authorName":"朱宏","id":"277dc173-ec72-4c42-a919-121d095561c1","originalAuthorName":"朱宏"}],"doi":"","fpage":"88","id":"8aeeeed0-1991-4dd6-9a35-1ac2f13b9c31","issue":"17","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"5d81191e-4109-4ff0-846f-6061a6ab6d4c","keyword":"聚酰胺-胺","originalKeyword":"聚酰胺-胺"},{"id":"d1ecce41-94e4-4ba7-b7f2-e1b4e6788f5e","keyword":"叶酸","originalKeyword":"叶酸"},{"id":"29b6f42a-3649-4063-855a-d67d75f040bd","keyword":"<span style=\"color:red\">靶向</span>药物输送","originalKeyword":"靶向药物输送"}],"language":"zh","publisherId":"cldb201217019","title":"叶酸<span style=\"color:red\">靶向</span>PAMAM载药系统在肿瘤治疗中的研究进展","volume":"26","year":"2012"},{"abstractinfo":"简要介绍了磁性<span style=\"color:red\">靶向</span>载药微球的特性及其作用原理,综述了制备磁性<span style=\"color:red\">靶向</span>载药微球的几种传统方法,并着重介绍了一种绿色有效的制备磁性<span style=\"color:red\">靶向</span>载药微球的方法——超临界CO2抗溶剂法.最后对超临界CO2抗溶剂法制备磁性<span style=\"color:red\">靶向</span>载药微球做了展望.","authors":[{"authorName":"张楠","id":"e30ddec1-0a9c-438a-9c2e-4ce64bccc725","originalAuthorName":"张楠"},{"authorName":"赵启成","id":"c66bcd92-1791-4324-9002-fabf04d95303","originalAuthorName":"赵启成"},{"authorName":"王卫京","id":"0b435926-fffb-4e57-911e-795b05b9725a","originalAuthorName":"王卫京"},{"authorName":"陈淑花","id":"4a5f1668-40e2-4594-9cc7-3e9566e4fc6d","originalAuthorName":"陈淑花"},{"authorName":"丁仕强","id":"703c3fc7-e938-4fda-bae5-db38406a3967","originalAuthorName":"丁仕强"},{"authorName":"詹世平","id":"eeba31c5-ff9e-4531-a5b7-74f5bea40bb0","originalAuthorName":"詹世平"}],"doi":"","fpage":"81","id":"e92ab090-a1e5-489a-80c3-80b71fe10e18","issue":"23","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"d519f4a6-c176-4c5e-af35-4a61bc3e13c5","keyword":"磁性<span style=\"color:red\">靶向</span>药物","originalKeyword":"磁性靶向药物"},{"id":"cefe12f1-f79b-45b8-a87c-e0d99ea26e2d","keyword":"载药微球","originalKeyword":"载药微球"},{"id":"69890551-74d0-4c2b-b89a-2b10a739bacb","keyword":"超临界CO2抗溶剂法","originalKeyword":"超临界CO2抗溶剂法"}],"language":"zh","publisherId":"cldb201323018","title":"超临界CO2辅助制备磁性<span style=\"color:red\">靶向</span>载药微粒","volume":"27","year":"2013"},{"abstractinfo":"<span style=\"color:red\">被动</span>式直接甲醇燃料电池作为新型便携式电源,势必会遇到负载动态变化的工作环境.本文针对持续加载/瞬间筇载、持续加载/持续卸载及梯形加载时<span style=\"color:red\">被动</span>式直接甲醇燃料电池的动态响应进行了实验研究,获得了变负载时电池电压及温度的响应规律.结果表明:加载时电池电压降低、温度升高,而卸载瞬间电压骤升、温度骤降;持续卸载时温度响应滞后于电流密度的变化及电压响应;梯形加载时恒流放电过程对持续加载和卸载时电压响应的影响较小;电池温度随加载周期整体上呈升高趋势.","authors":[{"authorName":"叶丁丁","id":"84fecebe-52eb-4fad-80fc-3e929d378f00","originalAuthorName":"叶丁丁"},{"authorName":"朱恂","id":"4c1bf982-1a2c-42f6-a99d-814c98bf8716","originalAuthorName":"朱恂"},{"authorName":"李俊","id":"d7b4efff-847c-40e9-9a46-bc53bacb8a39","originalAuthorName":"李俊"},{"authorName":"蒲洪权","id":"c87ea41e-952a-4e0a-840e-16bbb29af25c","originalAuthorName":"蒲洪权"},{"authorName":"廖强","id":"a37ed57f-9db4-49fe-b1e0-a6128b1a39b2","originalAuthorName":"廖强"}],"doi":"","fpage":"106","id":"93301c12-101b-4bed-98e8-51fc41aa63ce","issue":"1","journal":{"abbrevTitle":"GCRWLXB","coverImgSrc":"journal/img/cover/GCRWLXB.jpg","id":"32","issnPpub":"0253-231X","publisherId":"GCRWLXB","title":"工程热物理学报   "},"keywords":[{"id":"520a74b6-a673-40ed-ac3e-29423df2de23","keyword":"<span style=\"color:red\">被动</span>式","originalKeyword":"被动式"},{"id":"df8d5c18-73de-486c-b575-e770ed345141","keyword":"直接甲醇燃料电池","originalKeyword":"直接甲醇燃料电池"},{"id":"87f18534-a25b-41ee-b446-59f90c859479","keyword":"动态响应","originalKeyword":"动态响应"},{"id":"b8a91a36-8611-490b-b8c9-556a7e64803e","keyword":"电池温度","originalKeyword":"电池温度"}],"language":"zh","publisherId":"gcrwlxb201301026","title":"<span style=\"color:red\">被动</span>式DMFC变负载动态响应特性","volume":"34","year":"2013"},{"abstractinfo":"为评价相变储能墙板应用于主动和<span style=\"color:red\">被动</span>式节能建筑的热工性能，根据相变储能材料的特性提出了相对时间滞后率、节能效率以及峰温差3个评价指标.在此基础上研制了节能评价装置，利用相变石膏板和绝热材料导热系数参比板(参比板)进行对比实验，对相变储能墙板应用于主动式和<span style=\"color:red\">被动</span>式节能建筑的节能效果及对室内热环境的影响进行了评价研究.结果表明，相变材料掺量为5％的相变石膏板由初始温度上升至人体舒适温度上限的平均时间比参比板滞后约8．5％，维持室内人体舒适温度所耗电能节约23％，峰值温度低0．9℃.相变储能材料的加入提高了主动式和<span style=\"color:red\">被动</span>式节能建筑的节能效率，改善了室内居住环境，具有较高的工程应用价值.","authors":[{"authorName":"周全","id":"5b8b27cd-8b6d-4d69-a595-4495e6d6ee85","originalAuthorName":"周全"},{"authorName":"郭红斌","id":"2617fbd4-7198-460d-a2c1-301597dedc83","originalAuthorName":"郭红斌"},{"authorName":"周胜男","id":"d904db04-5f53-4fa5-9a82-ea966f1265c1","originalAuthorName":"周胜男"},{"authorName":"李清海","id":"3010f63f-a08a-41f8-94ca-3125ce4ad0bf","originalAuthorName":"李清海"},{"authorName":"李东旭","id":"782f8dbe-badc-4216-b81b-b2375e2473e4","originalAuthorName":"李东旭"}],"doi":"10.3969/j.issn.1001-9731.2014.11.003","fpage":"11013","id":"0ecf4022-b824-4b54-9efc-397c7f1c5547","issue":"11","journal":{"abbrevTitle":"GNCL","coverImgSrc":"journal/img/cover/GNCL.jpg","id":"33","issnPpub":"1001-9731","publisherId":"GNCL","title":"功能材料"},"keywords":[{"id":"9933cd40-57a6-43d3-944b-b316174aee72","keyword":"相变材料","originalKeyword":"相变材料"},{"id":"2b0ce5aa-3e22-4d0b-a7c7-6ea5dde1b350","keyword":"节能","originalKeyword":"节能"},{"id":"4dfa21ce-e8ed-4c81-9abb-d846df662e3e","keyword":"评价","originalKeyword":"评价"},{"id":"f7c0d44b-a907-444a-88c0-ba0062c0a24f","keyword":"热物理性能","originalKeyword":"热物理性能"}],"language":"zh","publisherId":"gncl201411003","title":"相变储能墙板主<span style=\"color:red\">被动</span>节能评价方法研究","volume":"","year":"2014"},{"abstractinfo":"恶性肿瘤是一种严重威胁人类健康的常见病和多发病,是引起死亡的主要原因之一.近年来,抗肿瘤药物的<span style=\"color:red\">靶向</span>性研究越来越受到人们的重视.发展抗肿瘤药物的新型<span style=\"color:red\">靶向</span>载体,增加药物<span style=\"color:red\">靶向</span>性,提高生物利用度,降低毒副作用,是目前备受关注的课题.根据近年来文献,综述了一些新型的抗肿瘤药物载体,包括<span style=\"color:red\">靶向</span>的脂质体载药系统、纳米粒载药系统、微粒载药系统、胶束载药系统等,并分别总结了其颗粒大小、载药类型、载药模式及治疗效果等,为肿瘤的<span style=\"color:red\">靶向</span>给药研究提供思路.","authors":[{"authorName":"杨眉","id":"90d7cc0e-f4d6-4772-a86b-a606f8540036","originalAuthorName":"杨眉"},{"authorName":"李钰","id":"0c0d9a83-47a8-4a30-b7f7-fb854614fa9b","originalAuthorName":"李钰"},{"authorName":"徐冬燕","id":"a56b8588-467f-4675-ac2e-bd7d432d127d","originalAuthorName":"徐冬燕"},{"authorName":"侯长军","id":"b31d0269-b1dd-48f9-9f69-26deae2a29cb","originalAuthorName":"侯长军"},{"authorName":"法焕宝","id":"d07d3805-d410-4c08-a945-ad0d83400045","originalAuthorName":"法焕宝"},{"authorName":"霍丹群","id":"02e4e28e-d3f4-494f-b27e-56795326e67f","originalAuthorName":"霍丹群"}],"doi":"","fpage":"60","id":"6f4ea2b2-37b7-45b1-943c-32395cf2ccea","issue":"3","journal":{"abbrevTitle":"CLDB","coverImgSrc":"journal/img/cover/CLDB.jpg","id":"8","issnPpub":"1005-023X","publisherId":"CLDB","title":"材料导报"},"keywords":[{"id":"bc9e70cc-cd79-420d-8c25-4754b41a58f4","keyword":"<span style=\"color:red\">靶向</span>","originalKeyword":"靶向"},{"id":"351cc666-4687-40a6-aa72-60b8127def18","keyword":"抗肿瘤","originalKeyword":"抗肿瘤"},{"id":"feea92ca-d565-4c87-a11b-1ea0092ddbe7","keyword":"药物载体","originalKeyword":"药物载体"}],"language":"zh","publisherId":"cldb201403013","title":"<span style=\"color:red\">靶向</span>型药物载体在抗肿瘤治疗中的研究进展","volume":"28","year":"2014"},{"abstractinfo":"采用甲基磺酸盐体系镀液在0603型陶瓷电阻表面电镀纯锡,表征了纯锡镀层的厚度、微观结构和可焊性.通过计算镀层厚度的CPK(制程能力指数)和产品双联率,分析了该镀锡工艺生产过程的稳定性.结果表明,镀层均匀、致密,可焊性良好,CPK大于1.33,产品双联率较低,说明本镀锡工艺适用于<span style=\"color:red\">被动</span>元件的工业化生产.","authors":[{"authorName":"任秀斌","id":"d8159a86-740c-4f2c-a1f9-195739a0eb3e","originalAuthorName":"任秀斌"},{"authorName":"裘宇","id":"538d0363-db93-4dc7-ae9e-858adc3c0734","originalAuthorName":"裘宇"},{"authorName":"吴水","id":"50498fc5-737b-4f68-b04f-a3bf055e7636","originalAuthorName":"吴水"},{"authorName":"肖定军","id":"d160aee6-7f00-4bfe-adb0-e3704bde312f","originalAuthorName":"肖定军"},{"authorName":"安茂忠","id":"ad6d89cc-30fb-49e3-a14f-12db78c552d7","originalAuthorName":"安茂忠"}],"doi":"","fpage":"1123","id":"8736bb98-0530-4e6d-95d7-56e1e5d85ef4","issue":"19","journal":{"abbrevTitle":"DDYTS","coverImgSrc":"journal/img/cover/DDYTS.jpg","id":"21","issnPpub":"1004-227X","publisherId":"DDYTS","title":"电镀与涂饰   "},"keywords":[{"id":"452b60a2-ba08-499a-8f13-38738ce71c8a","keyword":"<span style=\"color:red\">被动</span>元件","originalKeyword":"被动元件"},{"id":"7eb1a0f4-ece6-4158-93bc-d14dd5953f98","keyword":"纯锡","originalKeyword":"纯锡"},{"id":"a39c25b0-3026-4814-ab1d-0831f1477ed4","keyword":"电镀","originalKeyword":"电镀"},{"id":"ec713d9f-e417-474a-95e4-252031184daa","keyword":"甲基磺酸盐","originalKeyword":"甲基磺酸盐"},{"id":"4b1a15f9-b98c-45be-952b-a0fa4573a8cc","keyword":"制程能力指数","originalKeyword":"制程能力指数"},{"id":"1d755739-9b9e-4ce4-9786-1caa97add2d0","keyword":"可焊性","originalKeyword":"可焊性"}],"language":"zh","publisherId":"ddyts201519009","title":"<span style=\"color:red\">被动</span>元件甲基磺酸盐体系电镀纯锡","volume":"34","year":"2015"}],"totalpage":26,"totalrecord":257}