Study on Antifouling Activity of Bacteria Associated with Marine Sponge Mycale phyllophila

从叶片山海绵(MyCAlE PHyllOPHIlA)中分离纯化得到7株共附生细菌,经16SrdnA序列比对,分别归属于芽孢杆菌属(bACIlluS,5株)、假弧菌属(PSEudOVIbrIO,1株)和短杆菌属(brEVIbACTErIuM,1株).菌株经发酵培养后对发酵液进行提取,以翡翠贻贝(PErnA VIrIdIS)足丝分泌抑制实验检测提取物的防污活性.检测结果表明,菌株nAP1和nAP7的提取物显著抑制翡翠贻贝足丝分泌,其半抑制浓度(EC50)分别为55.26和14.85μg/Ml,其余5株菌株的提取物均无防污活性.结合形态观察、生理生化特征和16SrdnA序列比对,将菌株nAP7初步鉴定为脱氮假弧菌(PSEudOVIbrIO dEnITrIfICAnS).另外,进一步对菌株nAP7提取物进行活性部位追踪,以不同极性的溶剂进行萃取,依次获得石油醚相、二氯甲烷相、乙酸乙酯相、正丁醇相和水相部分,进行防污活性检测,发现除水相部分无防污活性外,其余4个部分均显著抑制翡翠贻贝足丝分泌,其中正丁醇相不仅防污活性高(EC50=4.06μg/Ml),对翡翠贻贝的毒性也低(半致死浓度(lC50)=158.11μg/Ml),表明其中含有高效低毒的活性成分.研究结果为从海洋微生物中筛选获得新型环保海洋防污剂奠定重要基础.Seven bacterial strains were isolated from marine sponge Mycale phyllophila.Based on comparative analysis of their 16 S rDNA sequences,five strains were affiliated to the genus Bacillus,one to the genus Pseudovibrio,and one to the genus Brevibacterium.And then,they were subjected to fermentation and the extracts of culture broth were tested for antifouling activity using the bioassay of byssus thread production with the green mussel Perna viridis.The results showed that the extracts of the bacterial strains NAP1 and NAP7significantly inhibited byssus thread production of P.viridis,with EC50 of 55.26 and 14.85μg/mL,respectively.The extracts of the other five strains had no antifouling activity.Additionally,the extract of the strain NAP7 were further investigated for its active fraction.It was separated with solvents of different polarities.Petroleum ether fraction,methylene dichloride fraction,ethyl acetate fraction,n-butanol fraction and water fraction were obtained successively and then tested for antifouling activity.Although there was no antifouling activity in the water extract,the other four fractions significantly inhibited byssus thread production of P.viridis.Especially,the n-butanol fraction was highly antifouling active(EC50=4.06μg/mL)and not very toxic(LC50=158.11μg/mL),indicating that this fraction contained substance(s)with high antifouling activity and low toxicity.The findings of this study are important for screening environmentally friendly marine antifoulants from marine microorganisms.国家自然科学基金(41106121); 海洋公益性行业科研专项(201305016); 厦门市海洋经济创新发展区域示范重点项目(12PZB001SF09); 厦门大学海洋科学基地科研训练及科研能力提高项目(J1210050

MEAW技术在正颌术后[牙合]精细调整中的临床应用

【目的】探讨MEAW技术在骨性错畸形正颌术后精细调整中的应用。【方法】选择中山大学附属口腔医院正颌中心2000年12月至2005年12月期间使用标准方丝弓技术行术前正畸-正颌外科后遗留局部小开[牙合],尖窝关系咬[牙合]不良、中线不齐、深覆[牙合]、[牙合]平面倾斜等错[牙合]的病例30例,年龄17～40岁,平均年龄24.5岁,采用MEAW技术加颌间弹力牵引,进行牙位及咬[牙合]关系的精细调整。【结果】经过MEAW技术2-4个月的调整,全部病例均达到预期的矫治效果：磨牙Ⅰ类关系,中线齐,建立了正常的覆[牙合]覆盖和良好的尖窝咬[牙合]关系。【结论】MEAW技术可高效应用于正颌术后[牙合]精细调整

不同上方来水模式下工程堆积体坡面的植被调控

为揭示植被格局对工程堆积体坡面水沙调控的影响，采用野外模拟径流冲刷试验，分析了 4 种上方来水模式（均 匀型、峰值前型、峰值中型和峰值后型）下坡面 5 种覆草格局（裸坡、坡顶聚集、坡中聚集、坡底聚集和带状格局）的 侵蚀特征。结果表明：水流功率与土壤剥蚀率之间相关性最高且呈极显著幂函数关系（R2 =0.47～0.72，P&lt;0.01），是描述 堆积体侵蚀动力机制的最优参数。植被格局的减流效益在 12.23%～49.62%之间，减沙效益在 12.92%～80.54%之间，减 沙效益高于减流效益；带状和坡顶聚集格局的平均减流减沙效益分别为 43.87%、58.09%和 30.55%、54.41%，显著优于 其他植被格局，在治理堆积体水土流失时应优先考虑这两种植被格局。植被格局下侵蚀泥沙中砂粒含量较对照小区减小 了 18.79%～35.80%，黏粒含量增加了 3.56%～10.69%，表明植被对砂粒的拦截效果显著；侵蚀泥沙颗粒体积分形维数主 要由黏粒体积分数决定，两者呈极显著线性相关关系（R2 =0.90，P&lt;0.01）。植被格局的砂粒富集率较对照小区相对减小， 黏粒富集率相对增加，体积分形维数增大；侵蚀泥沙中黏粒和砂粒迁移方式以团粒为主，粉粒则以单粒为主。该研究可 为工程堆积体水土流失植被防控措施的配置提供参考。</div

膜下滴灌棉花水肥耦合效应研究初报

对膜下滴灌棉花的水肥耦合效应进行了田间试验。结果表明 :在灌水量不足、农业资源未能充分发挥条件下 ,棉花产量与灌水量及耗水量呈线性关系 ;膜下滴灌棉花的水肥耦合效应明显 ,水肥都具有增产效果 ,但过多的水肥投入并不有利于棉花增产。最后对进一步完善膜下滴灌棉花水肥耦合试验提出了建议

Expert consensus on the management of dermatogenic chronic pruritus in children

瘙痒见于多种疾病,在儿童多由皮肤疾病导致,即皮肤源性瘙痒.持续存在的慢性瘙痒治疗困难,可对患儿的睡眠、情绪、认知、学校表现及社会家庭功能等方面产生负面影响,严重影响患儿及其家庭成员的生活质量.临床上迫切需要对儿童慢性瘙痒进行规范化管理,而目前国内外缺乏独立的儿童慢性瘙痒诊疗指南或共识.该共识根据循证医学证据及专家意见,制定了一套针对0～18岁儿童皮肤源性慢性瘙痒的管理方案,供临床医生参考.</p

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements