Article(id=1152987122341503618, tenantId=1146029695717560320, journalId=1146119944283992078, issueId=1152987119267078751, articleNumber=null, orderNo=null, doi=null, pmid=null, cstr=null, oa=null, hot=null, price=null, onlineType=0, articleFormat=0, articleType=null, articleTypeStr=null, receivedDate=null, receivedDateStr=null, revisedDate=null, revisedDateStr=null, acceptedDate=null, acceptedDateStr=null, onlineDate=1752823151431, onlineDateStr=2025-07-18, pubDate=1737561600000, pubDateStr=2025-01-23, doiRegisterDate=null, doiRegisterDateStr=null, onlineIssueDate=1752823151431, onlineIssueDateStr=2025-07-18, onlineJustAcceptDate=null, onlineJustAcceptDateStr=null, onlineFirstDate=null, onlineFirstDateStr=null, sourceXml=null, magXml=null, createTime=1752823151431, creator=13701087609, updateTime=1752823151431, updator=13701087609, issue=Issue{id=1152987119267078751, tenantId=1146029695717560320, journalId=1146119944283992078, year='2025', volume='3', issue='2', pageStart='1', pageEnd='160', issueExtLink='null', onlineDate='null', pubDate='null', beforeIssueId=null, nextIssueId=null, price=null, status=1, issueComplete=1, articleOrder=1, issueType=-1, specialIssue=null, createTime=1752823150696, creator=13701087609, updateTime=1753700669186, updator=13701087609, preIssue=null, nextIssue=null, ext={EN=IssueExt(id=1156667698588275453, tenantId=1146029695717560320, journalId=1146119944283992078, issueId=1152987119267078751, language=EN, specialIssueTitle=, coverIllustrator=, specialIssueEditor=, specialIssueAbout=), CN=IssueExt(id=1156667698588275454, tenantId=1146029695717560320, journalId=1146119944283992078, issueId=1152987119267078751, language=CN, specialIssueTitle=, coverIllustrator=, specialIssueEditor=, specialIssueAbout=)}, issueFiles=null}, startPage=53, endPage=55, ext={CN=ArticleExt(id=1152987123062923923, articleId=1152987122341503618, tenantId=1146029695717560320, journalId=1146119944283992078, language=CN, title=食品中农药残留检测方法中酶联免疫吸附法的应用与优化研究, columnId=1151957373175820401, journalTitle=实验室检测, columnName=创新应用, runingTitle=null, highlight=null, articleAbstract=
目的 本研究旨在评估酶联免疫吸附法(Enzymelinked immunosorbent assay,ELISA)在食品中农药残留快速筛查中的应用效果。方法 实验基于NY/T 761—2008标准,选取蔬菜和水果共11个样品,采用气相色谱法作为参比方法,平行开展 ELISA 快速检测,评估其灵敏度、特异性和相对准确度等性能指标。结果 研究结果显示,ELISA法检测的灵敏度为66.70%,特异性为80%,相对准确度为72.70%,在低浓度样品的检测中存在一定的假阳性和假阴性现象。结论 ELISA法操作简便、检测快速,适合作为农药残留快速筛查的初筛手段;通过优化抗体特异性、改进样品前处理及开发多重检测平台,可进一步提升 ELISA法的检测性能,为食品安全快速筛查提供技术支持。
, correspAuthors=蔡怡, authorNote=null, correspAuthorsNote=
, copyrightStatement=null, copyrightOwner=null, extLink=null, articleAbsUrl=null, sourceXml=XTG9V+8VwvMkU1bbLcDw0g==, magXml=4pSGrHW4JJPA/HT1U51wGg==, pdfUrl=null, pdf=aEi0qaLb2UcRnF+EUvVK9g==, pdfFileSize=null, pdfExtLink=null, richHtmlUrl=null, mobilePdfUrl=null, reviewReport=null, pdfFirstPage=null, abstractGraph=null, abstractGraphContent=null, abstractVideo=null, citation=null, cebUrl=null, magXmlContent=ukNiNBUlUDduW8kZ04EYYQ==, mapNumber=null, authorCompany=null, fund=null, authors=null, authorsList=蔡怡)}, authors=[Author(id=1154798402337624779, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, orderNo=0, firstName=null, middleName=null, lastName=null, nameCn=null, orcid=null, stid=null, country=null, authorPic=null, dead=0, email=haoyan202307@163.com, emailSecond=null, emailThird=null, correspondingAuthor=1, authorType=1, ext={CN=AuthorExt(id=1154798402417316557, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, authorId=1154798402337624779, language=CN, stringName=蔡怡, firstName=null, middleName=null, lastName=null, prefix=null, suffix=null, authorComment=null, nameInitials=null, affiliation=null, department=null, xref=
*, address=阿克苏地区市场监督管理局 食品药品安全审查服务中心 阿克苏 843000, bio=null, bioImg=null, bioContent=null, aboutCorrespAuthor=null)}, companyList=[AuthorCompany(id=1154798402253738695, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, xref=null, ext=[AuthorCompanyExt(id=1154798402257933000, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, companyId=1154798402253738695, language=CN, country=null, province=null, city=null, postcode=null, companyName=null, departmentName=null, remark=阿克苏地区市场监督管理局 食品药品安全审查服务中心 阿克苏 843000)])])], keywords=[Keyword(id=1154798402807386830, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, orderNo=1, keyword=农药残留), Keyword(id=1154798402891272911, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, orderNo=2, keyword=食品安全), Keyword(id=1154798402958381778, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, orderNo=3, keyword=快速筛查), Keyword(id=1154798403021296339, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, orderNo=4, keyword=酶联免疫吸附法)], refs=[Reference(id=1154798405395272444, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=46, issue=08, pageStart=1, pageEnd=13, url=null, language=null, rfNumber=[1], rfOrder=0, authorNames=张婷, 喻明辉, 覃重阳, journalName=中国茶叶, refType=null, unstructuredReference=张婷, 喻明辉, 覃重阳, 等 . 茶叶中农药残留常规检测方法研究进展[J].
中国茶叶,
2024,
46(08): 1-13., articleTitle=茶叶中农药残留常规检测方法研究进展, refAbstract=null), Reference(id=1154798405458187006, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=null, issue=18, pageStart=67, pageEnd=70, url=null, language=null, rfNumber=[2], rfOrder=1, authorNames=陈露婷, 章慧芳, 俞慧芳, journalName=当代化工研究, refType=null, unstructuredReference=陈露婷, 章慧芳, 俞慧芳, 等 . 免疫分析技术在农药残留检测中的研究进展[J].
当代化工研究,
2024, 18): 67-70., articleTitle=免疫分析技术在农药残留检测中的研究进展, refAbstract=null), Reference(id=1154798405516907264, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=null, issue=29, pageStart=173, pageEnd=179, url=null, language=null, rfNumber=[3], rfOrder=2, authorNames=张淑媛, journalName=食品安全导刊, refType=null, unstructuredReference=张淑媛. 潍坊市食品安全快速检测技术研究[J].
食品安全导刊,
2024, 29): 173-179., articleTitle=潍坊市食品安全快速检测技术研究, refAbstract=null), Reference(id=1154798405584016130, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=41, issue=09, pageStart=62, pageEnd=66, url=null, language=null, rfNumber=[4], rfOrder=3, authorNames=何娟, 肖祥飞, 郎小琴, journalName=农技服务, refType=null, unstructuredReference=何娟, 肖祥飞, 郎小琴, 等 . 草莓农药残留快速检测试剂盒的农药敏感性及检测准确度[J].
农技服务,
2024,
41(09): 62-66., articleTitle=草莓农药残留快速检测试剂盒的农药敏感性及检测准确度, refAbstract=null), Reference(id=1154798405646930695, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=null, issue=25, pageStart=155, pageEnd=157, url=null, language=null, rfNumber=[5], rfOrder=4, authorNames=陈丛婧, journalName=食品安全导刊, refType=null, unstructuredReference=陈丛婧. 蔬菜安全检测中农残速测技术的运用分析[J].
食品安全导刊,
2024, 25): 155-157., articleTitle=蔬菜安全检测中农残速测技术的运用分析, refAbstract=null), Reference(id=1154798405697262346, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=null, issue=29, pageStart=125, pageEnd=127, url=null, language=null, rfNumber=[6], rfOrder=5, authorNames=徐蕊, journalName=食品安全导刊, refType=null, unstructuredReference=徐蕊. 食品检验中常见污染物的检测方法[J].
食品安全导刊,
2024, 29): 125-127., articleTitle=食品检验中常见污染物的检测方法, refAbstract=null), Reference(id=1154798405764371212, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=45, issue=11, pageStart=308, pageEnd=312, url=null, language=null, rfNumber=[7], rfOrder=6, authorNames=刘顺, 黎波, 段向毓, journalName=食品工业, refType=null, unstructuredReference=刘顺, 黎波, 段向毓, 等 . 食用水产品中兽药残留快速检测产品性能评价[J].
食品工业,
2024,
45(11): 308-312., articleTitle=食用水产品中兽药残留快速检测产品性能评价, refAbstract=null), Reference(id=1154798405844062990, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=3, issue=05, pageStart=476, pageEnd=481, url=null, language=null, rfNumber=[8], rfOrder=7, authorNames=张继梅, 冯文霞, 白新明, journalName=寒旱农业科学, refType=null, unstructuredReference=张继梅, 冯文霞, 白新明, 等 . 胶体金免疫层析法在韭菜农药残留检测中的应用研究[J].
寒旱农业科学,
2024,
3(05): 476-481., articleTitle=胶体金免疫层析法在韭菜农药残留检测中的应用研究, refAbstract=null), Reference(id=1154798405890200336, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=null, issue=04, pageStart=80, pageEnd=83, url=null, language=null, rfNumber=[9], rfOrder=8, authorNames=王扬, 柯庆青, 李诗言, journalName=中国水产, refType=null, unstructuredReference=王扬, 柯庆青, 李诗言, 等 . 水产品药物残留快速检测质量控制技术探讨[J].
中国水产,
2024, 04): 80-83., articleTitle=水产品药物残留快速检测质量控制技术探讨, refAbstract=null), Reference(id=1154798405961503506, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, doi=null, pmid=null, pmcid=null, year=2024, volume=26, issue=01, pageStart=96, pageEnd=103, url=null, language=null, rfNumber=[10], rfOrder=9, authorNames=王韦达, 杨睿, 郑彦婕, journalName=食品与药品, refType=null, unstructuredReference=王韦达, 杨睿, 郑彦婕, 等 . 国内外食品快速检测方法评价技术研究[J].
食品与药品,
2024,
26(01): 96-103., articleTitle=国内外食品快速检测方法评价技术研究, refAbstract=null)], funds=null, companyList=[AuthorCompany(id=1154798402253738695, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, xref=null, ext=[AuthorCompanyExt(id=1154798402257933000, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, companyId=1154798402253738695, language=CN, country=null, province=null, city=null, postcode=null, companyName=null, departmentName=null, remark=阿克苏地区市场监督管理局 食品药品安全审查服务中心 阿克苏 843000)])], figs=[ArticleFig(id=1154798404975842031, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=EN, label=null, caption=null, figureFileSmall=null, figureFileBig=null, tableContent=
| 样本编号 | 气相色谱法检测结果(mg/kg) | 气相色谱法结果 |
| 苹果 | 1 | 0.005 | 阴性 |
| 2 | 0.012 | 阳性 |
| 3 | 0.018 | 阳性 |
| 大白菜 | 1 | 0.009 | 阴性 |
| 2 | 0.015 | 阳性 |
| 菠菜 | 1 | 0.004 | 阴性 |
| 2 | 0.014 | 阳性 |
| 葡萄 | 1 | 0.007 | 阴性 |
| 2 | 0.013 | 阳性 |
| 3 | 0.016 | 阳性 |
| 4 | 0.005 | 阴性 |
), ArticleFig(id=1154798405034562289, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, label=表 1, caption=
气相色谱法检测结果, figureFileSmall=null, figureFileBig=null, tableContent=
| 样本编号 | 气相色谱法检测结果(mg/kg) | 气相色谱法结果 |
| 苹果 | 1 | 0.005 | 阴性 |
| 2 | 0.012 | 阳性 |
| 3 | 0.018 | 阳性 |
| 大白菜 | 1 | 0.009 | 阴性 |
| 2 | 0.015 | 阳性 |
| 菠菜 | 1 | 0.004 | 阴性 |
| 2 | 0.014 | 阳性 |
| 葡萄 | 1 | 0.007 | 阴性 |
| 2 | 0.013 | 阳性 |
| 3 | 0.016 | 阳性 |
| 4 | 0.005 | 阴性 |
), ArticleFig(id=1154798405089088243, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=EN, label=null, caption=null, figureFileSmall=null, figureFileBig=null, tableContent=
| 样本编号 | | ELISA 检测结果 | ELISA 结果类型 |
| 苹果 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 3 | 阳性 | 真实阳性(TP) |
| 大白菜 | 1 | 阳性 | 假阳性(FP) |
| 2 | 阴性 | 假阴性(FN) |
| 菠菜 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 葡萄 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 3 | 阴性 | 假阴性(FN) |
| 4 | 阴性 | 真实阴性(TN) |
), ArticleFig(id=1154798405168780021, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, label=表 2, caption=
ELISA 检测结果, figureFileSmall=null, figureFileBig=null, tableContent=
| 样本编号 | | ELISA 检测结果 | ELISA 结果类型 |
| 苹果 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 3 | 阳性 | 真实阳性(TP) |
| 大白菜 | 1 | 阳性 | 假阳性(FP) |
| 2 | 阴性 | 假阴性(FN) |
| 菠菜 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 葡萄 | 1 | 阴性 | 真实阴性(TN) |
| 2 | 阳性 | 真实阳性(TP) |
| 3 | 阴性 | 假阴性(FN) |
| 4 | 阴性 | 真实阴性(TN) |
), ArticleFig(id=1154798405231694583, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=EN, label=null, caption=null, figureFileSmall=null, figureFileBig=null, tableContent=
| 性能指标 | ELISA 试剂盒 | 气相色谱法 |
| 灵敏度 | 100% | 66.70% |
| 特异性 | 100% | 80% |
| 相对准确度 | 100% | 72.70% |
), ArticleFig(id=1154798405290414841, tenantId=1146029695717560320, journalId=1146119944283992078, articleId=1152987122341503618, language=CN, label=表 3, caption=
关键性能指标, figureFileSmall=null, figureFileBig=null, tableContent=
| 性能指标 | ELISA 试剂盒 | 气相色谱法 |
| 灵敏度 | 100% | 66.70% |
| 特异性 | 100% | 80% |
| 相对准确度 | 100% | 72.70% |
)], attaches=null, journal=Journal(id=1146118849029578755, delFlag=0, nameCn=实验室检测, nameEn=Laboratory Testing, nameHistory1=null, nameHistory2=null, issn=2097-261X, eissn=, cn=10-1875/TB, coden=null, periodic=0, language=CN, oaType=是, ccby=null, superviseOffice=null, ownerOffice=null, pubOffice=null, editorOffice=null, officeType=null, aims=null, clcCode=null, officeProv=null, officeCity=null, officeAddr=null, officeZip=null, officeEmail=null, officePhone=null, editDirector=null, officeDirector=null, officeDirectorPhone=null, officeStaffNum=null, officeEmpNum=null, coverPicUrl=Dmoi7fiemaDGWUxiXPMi1g==, journalPrice=null, startedYear=null, abbrevIsoEn=Lab Test, journalRemark=null, publicationField=null, createdTime=null, updatedTime=1778470330175, createdBy=null, updatedBy=18614031015, firstLetterCn=L, firstLetterEn=L, subjectCode=Engineering, subjectName=工程, subjectCodeEn=Engineering, subjectNameEn=null, picCn=Dmoi7fiemaDGWUxiXPMi1g==, picEn=1VW7aV1haIq706bPcrSXYQ==, jcr=null, cjcr=null, exts=[JournalExt(id=1208043431218225520, language=CN, name=实验室检测, nameHistory1=null, nameHistory2=null, managedBy=国家市场监督管理总局, sponsoredBy=中国检验检测学会, publishedBy=《实验室检测》编辑部, editorOffice=, officeProv=null, officeCity=null, officeAddr=, officeZip=, editDirector=, officeDirector=null, officePhone=null, coverPicUrl=null, journalRemark=《实验室检测》(国内统一刊号: CN 10-1875/TB, 国际标准刊号: ISSN 2097-261X, 半月刊), 创刊于2023年5月, 由国家市场监督管理总局主管, 中国检验检测学会主办, 是一本国内外公开发行, 专注于实验室检测类的学术期刊。现已被《中国学术期刊网络出版总库》(CNKI)、“万方数据 数字化期刊群”等数据库全文收录。主要包括以下栏目: (1) 聚焦话题;(2) 热点解读;(3) 合规咨讯;(4) 研究前沿;(5) 创新应用;(6) 评价与分析;(7) 科创平台;(8) 标准推广, submitArticleUrl=null, websiteUrl=, createdTime=1765949598364, updatedTime=1765949598364, createdBy=13041195026, updatedBy=13041195026, submissionGuidelinesUrl=, submissionAuthorUrl=, submissionEditorUrl=, submissionReviewUrl=, submissionCeEditorUrl=, submissionAeEditorUrl=, option={"copyright":""}), JournalExt(id=1208043431264362865, language=EN, name=Laboratory Testing, nameHistory1=null, nameHistory2=null, managedBy=, sponsoredBy=, publishedBy=, editorOffice=, officeProv=null, officeCity=null, officeAddr=, officeZip=, editDirector=, officeDirector=null, officePhone=null, coverPicUrl=null, journalRemark=, submitArticleUrl=null, websiteUrl=, createdTime=1765949598375, updatedTime=1765949598375, createdBy=13041195026, updatedBy=13041195026, submissionGuidelinesUrl=, submissionAuthorUrl=, submissionEditorUrl=, submissionReviewUrl=, submissionCeEditorUrl=, submissionAeEditorUrl=, option={"copyright":""})], databaseList=null, tenantJournalId=1146119944283992078, websiteList=[Website(id=1148243202374623651, webName=null, webTitle=null, webDomain=null, webCopyrigh=null, webIpcNo=null, seoTitle=null, seoKeywords=null, seoDescription=null, tenantJournalId=null, journalId=1146119944283992078, journalNameCn=null, journalNameEn=null, grayFlag=null, tenantId=1146029695717560320, platformId=null, journalGroupId=null, journalGroupNameCn=null, journalGroupNameEn=null, type=1, domain=https://castjournals.cast.org.cn/joweb/sysjc/CN, language=CN, createTime=1751692112773, createBy=18614031015, updateTime=1753520557560, updateBy=18614031015, name=实验室检测-中文站点, tplId=1146099689490845704, title=实验室检测, delFlag=0, indexPage=/home, props=[WebsiteProps(id=1155912534570950828, tenantId=1146029695717560320, journalId=null, journalGroupId=null, siteId=1148243202374623651, code=articleTextType, value=kx, createTime=1753520624058, updateTime=1753520624058, creator=18614031015, updator=18614031015), WebsiteProps(id=1155912534554173609, tenantId=1146029695717560320, journalId=null, journalGroupId=null, siteId=1148243202374623651, code=banner, value=null, createTime=1753520624054, updateTime=1753520624054, creator=18614031015, updator=18614031015), WebsiteProps(id=1155912534545785000, tenantId=1146029695717560320, journalId=null, journalGroupId=null, siteId=1148243202374623651, code=logo, value=https://castjournals.cast.org.cn/joweb/kjdb/CN/file/pic?fileId=gxmh/wpj2QaxtghYq950Aw==, createTime=1753520624052, updateTime=1753520624052, creator=18614031015, updator=18614031015), WebsiteProps(id=1155912534562562219, tenantId=1146029695717560320, journalId=null, journalGroupId=null, siteId=1148243202374623651, code=picServerUrl, value=https://castjournals.cast.org.cn/joweb/kjdb/CN/file/pic, createTime=1753520624056, updateTime=1753520624056, creator=18614031015, updator=18614031015), WebsiteProps(id=1155912534558367914, tenantId=1146029695717560320, journalId=null, journalGroupId=null, siteId=1148243202374623651, code=staticResourcePath, value=https://castjournals.cast.org.cn/joweb/cast_kjdb_cn_619/, createTime=1753520624055, updateTime=1753520624055, creator=18614031015, updator=18614031015)])], journalTitle=实验室检测, weixinUrl=null, journalUrl=null, iacademicId=null, status=1, seqNo=null, journalTitleEn=Laboratory Testing, journalPhotoCn=Dmoi7fiemaDGWUxiXPMi1g==, journalPhotoEn=1VW7aV1haIq706bPcrSXYQ==, journalFirstLetter=L, journalRecommend=null, journalNew=null, journalCollection=null, jcrJf=null, cjcrJf=null, jcrJfStr=null, cjcrJfStr=null, submissionFirstDecision=null, sciSubjectClassification=null, casSubjectClassification=null, citeScore=null, totalCitationFrequency=null, icpCode=null, psCode=null, advertisingLicenseCode=null, copyrightInformation=null, country=null, option=, provinceCode=null, provinceName=null, collectFlag=false), detailUrlCn=https://castjournals.cast.org.cn/joweb/sysjc/CN/Y2025/V3/I2/53, detailUrlEn=/Y2025/V3/I2/53, pdfUrlCn=https://castjournals.cast.org.cn/joweb/sysjc/CN/PDF/Y2025/V3/I2/53, pdfUrlEn=/PDF/Y2025/V3/I2/53, aliStartDate=null, aliEndDate=null, collectionFlag=false, citedCount=null, citedUrl=null, reference=null)