Results 41 to 50 of about 71,844 (252)
鱼腥藻(蓝细菌)Pcc7120异形胞分化中的基因调控关系 [PDF]
, 2006 鱼腥藻(Anabaena sp．)PCC7120是由一列细胞组成的丝状固氮蓝藻,其固氮细胞——异形胞在藻丝中呈半规律分布,是原核生物细胞分化和图式形成的研究模式之一。在营养细胞分化为异形胞的过程中细胞分裂终止,光合放氧反应消失, 细胞外形成防止氧气透过的包被,最后固氮酶基因表达 ...
徐旭东
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Wildlife Letters, EarlyView.Using a 3‐year, broad‐scale camera‐trap network in western Kansas, we tested whether coyotes and American badgers exhibit spatiotemporal patterns consistent with coordinated hunting. Despite high diel activity overlap, detection‐conditioned co‐detections occurred far less frequently than expected under independence, and short‐term temporal sequencing ...
Ty J. Werdel +3 more
wiley +1 more source
Zhejiang Daxue xuebao. Lixue ban, 2016 研究了正辛烷、正辛烯、环辛烷和环辛烯4种不同结构C8烃在HZSM-5分子筛上的吸附及催化裂化性能. 结果表明，烃分子的类型和尺寸影响其在分子筛上的吸附与转化性能，受分子筛孔道尺寸的限制，未能进入分子筛孔道的环辛烷没有发生吸附和催化裂化反应，而环辛烯分子通过与分子筛孔道中的极性表面和质子酸中心的强作用进入孔道，能进入分子筛孔道的正辛烷和正辛烯的催化裂化程度与其被吸附固定性能相一致.
FANZheyong(范浙永) +3 more
doaj +1 more source
Wildlife Letters, EarlyView.Human‐caused leopard deaths in Sri Lanka averaged 9.65 ± 4.5 records year−1 over 17 years (2008–2024; n = 164), with records highly clustered in the central highland mosaic ecosystem. Mortality was dominated by adult males and driven primarily by snaring in plantation landscapes, and indicating an increase approximately 0.7–0.8 deaths per year.
Sanjaya Weerakkody +11 more
wiley +1 more source
, 2003 间充质干细胞具有多向分化功能,在体外培养时仍可保持其增殖和分化的能力,可以作为组织工程的一种较为理想的细胞来源。细胞与胞外环境之间以及细胞与细胞之间的相互作用对细胞增殖和分化具有重要影响。对干细胞的研究大多集中于生化因素的影响,而且一般是在静态的常规细胞培养容器中进行。在本研究中,尝试在骨髓间充质干细胞的培养过程中,施加不同的力学环境 ...
龙勉, 陶祖莱, 后晓南, 孙树津
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Zhejiang Daxue xuebao. Lixue ban, 2009 以五乙酰基葡萄糖和甲基丙烯酸-2-羟基乙酯(HEMA)为原料,以路易斯酸—三氟化硼乙醚络合物(BF3 •Et2O)为催化剂,方便地合成了一种含糖单体—甲基丙烯酸-2-（2',3',4' ,6'-四-O乙酰基-β-D-吡喃葡萄糖氧）乙酯(AcGEMA).该单体与丙烯腈(AN)经自由基溶液聚合的方法进行了共聚.单体和共聚物结构分别经红外、核磁证实.以水接触角测定脱乙酰保护后的含糖共聚物膜表面,结果表明脱乙酰化可显著提高膜表面亲水性.因此,用共聚法对聚丙烯腈膜改性,使其表面引入糖基,可以改善聚合物膜的亲水性 ...
WULi-li(吴莉莉) +2 more
doaj +1 more source
Wildlife Letters, EarlyView.We used spatially explicit capture‐recapture to estimate jaguar densities in a private reserve in the Colombian Llanos and quantified land cover change in and around the reserve from 2014 to 2024. Densities increased 22% since 2014, while disturbed land cover increased by 39%–54% around the reserve depending on buffer distance. Our study indicates that
Valeria Boron +7 more
wiley +1 more source
, 2000 运用21种限制性内切酶对银鲴自然群体进行了mtDNA的限制性片断长度多态性（RFLP）分析。发现银鲴自然群体存在丰富的mtDNA多态性，从4个群体39个个体中，共检测到12种单倍型，对这一现象的成因进行了探讨。依据单倍型和群体的系统发育关系，结合地理分布的资料 ...
肖武汉,张亚平
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Wildlife Letters, EarlyView.Reported annual per‐capita harvest of muskrats (PCHM) decreased as wetland complexity (total number of wetland patches) decreased in 13 state and federal wetland areas in the Midwest, USA. Our results support the hypothesis that regional‐scale declines in the abundance of muskrats are likely associated with the losses to wetland habitats throughout the
Tim L. Hiller +5 more
wiley +1 more source