产朊假丝酵母细胞和细胞壁对铜离子吸附能力观察

通过比较产朊假丝酵母细胞与分离纯化的细胞壁对铜离子吸附能力差异，探讨了细胞壁在酵母吸 重金属离子过程中的作用。结果表明，细胞壁吸附的铜郭量通常是细胞吸附量的５０％以上。     

产朊假丝酵母对铜离子的抗性与吸附能力

一定条件下,用含不同浓度CuSO4培养基培养产朊假丝酵母。实验结果,当CuSO4浓度高达10mnol／L时,菌体生长被完全抑制,产朊假丝酵母对铜离子有很强耐受力。菌体对铜离子吸附实验表明,随铜离子浓度增大,菌体对银离子吸附增强,说明菌体对铜离子的抗性与其吸附能力有关。     

油菜花秸秆制备的活性炭对铜离子吸附的实验研究

活性炭吸附法是处理含重金属废水的重要方法,本实验采用氢氧化钠活化法,以废弃的油菜花秸秆为原料,马弗炉加热炭化,水洗、干燥制备生物质活性炭,并用其对重金属铜离子进行了吸附实验。在正交实验设计的基础上,通过对实验结果的极差分析,得出结论：pH是影响铜离子去除率的主要因素,其次是活性炭颗粒的粒径。此外采用单因子控制法,定性分析了pH和颗粒粒径对铜离子去除率的影响,得出活性炭对铜离子吸附时的最佳pH为4～6,最适粒径为1.0mm。     

竹炭对铜(Ⅱ)离子的吸附性能研究

研究了竹炭粒径和用量、吸附时间、温度以及铜(Ⅱ)离子初始浓度等因素对铜(Ⅱ)离子吸附效果的影响.结果表明:竹炭对铜(Ⅱ)离子吸附率随其粒径的减小而增大,而随其用量的增加而增大;铜(Ⅱ)离子初始浓度增大,竹炭对其离子吸附率减小;竹炭对铜(Ⅱ)离子的吸附可在2h达到平衡,最佳吸附温度为30℃.竹炭对铜(Ⅱ)离子具有较好的吸附效果,是较为理想的吸附铜离子的材科.     

聚合物吸附剂的改性及其对重金属离子的吸附性能

根据最新文献报道,阐述了高聚物重金属离子吸附剂的合成及改性研究进展,尤其对改性聚合物对隔、铅、铜和汞等重金属离子的吸附性能进行了论述,归纳总结了影响吸附剂吸附性能的重要因素．指出化学改性法引入螯合基团是制备高性能重金属离子吸附剂的有效方法．这类吸附剂对重金属离子的吸附能力较强,对铅离子、汞离子和隔离子的吸附容量最高分别可达211、155和147mg／g．     

海鲜菇菌糠对废水中重金属铜离子的吸附性能研究

为了探究以海鲜菇菌糠作为生物吸附剂时,对废水中重金属Cu~(2+)的吸附性能。本文通过单因素静态吸附实验确定了溶液初始pH值、铜离子初始浓度、吸附剂加入量、吸附时间及吸附剂粒径大小对菌糠吸附性能的影响,通过L9(34)正交试验确定了最佳的吸附条件。结果表明,最佳单因素条件为:溶液初始pH 5、Cu~(2+)初始浓度10 mg/L、吸附时间150 min、吸附剂加入量28 g/L,吸附率最大为72%;正交试验分析显示Cu~(2+)初始浓度、吸附时间、吸附剂加入量、pH为显著因素,优化后Cu~(2+)初始浓度为15 mg/L、pH 5.5、吸附时间150 min、加入量为32 g/L,吸附率可达78%。海鲜菇菌糠作为一种高效环保经济的生物吸附剂对废水中重金属铜离子有较强的吸附能力,可望用于废水处理。     

模拟废水中重金属离子Cr^6＋的处理试验研究

论述了磺化煤的制备方法和原理。研究了磺化煤吸附模拟废水中重金属离子Cr6 的吸附特性及其粒度、用量、吸附作用时间、吸附温度、pH值和吸附液初始浓度对吸附量的影响,初步探讨了磺化煤吸附重金属离子的机理。试验研究表明,pH值是影响磺化煤吸附作用的主要因素,吸附性能随着pH增加发生变化。磺化煤吸附Cr6 的动力学研究表明,吸附符合一级吸附动力学模型。磺化煤对重金属离子的吸附模型符合Freundlich吸附等温式。     

NaClO改性ACFs对水中铜的吸附动力学和热力学研究

为改善活性炭纤维(ACFs)表面的酸性基团,并提高其对水中重金属离子的去除效率,采用NaClO对ACFs进行氧化改性,研究了吸附时间和温度对水溶液中铜离子的去除影响,用准一级、准二级动力学模型和内扩散模型来研究铜离子在改性ACFs上的吸附动力学行为。结果表明:铜离子在改性ACFs上的吸附平衡可以在50min内达到,且升高温度可以增加铜离子的去除率。准二级动力学模型可以很好地描述铜离子在改性ACFs的吸附行为,其相关系数R~20.99.根据吸附热力学的分析可知其标准吸附焓变ΔH00,该过程是吸热反应;且活化状态函数值是20.48kJ/mol,表明了该过程是以物理吸附为主。用改性ACFs去除水溶液中铜离子的性能明显比未改性的ACFs高,其去除率从70.2%增加到94.5%.     

铜离子耐受菌的筛选及其吸附特性研究

本研究旨在筛选出能够在较高铜离子浓度下生长并吸附铜离子的菌株,并对其吸附特性进行研究,以期为微生物处理重金属污染废水提供可靠的技术支持。本实验充分利用环境对微生物的胁迫作用,选择被铜离子污染的土壤,放入锥形瓶中并用水稀释后取上清夜涂布于含铜离子的4种培养基(即细菌、霉菌、放线菌和真菌固体培养基)。经过划线分离得到单菌落,从中挑选耐受能力最强的菌株,对其进行菌种16SrDNA鉴定及生长、吸附条件的优化。结果筛选到一株对铜离子耐受达到19 000mg/L的菌株,经鉴定为枯草芽孢杆菌,优化吸附条件后其对溶液中铜离子吸附率可以达到72%。实验筛选到的菌株具有改善和治理铜离子污染废水的潜力。     

凹凸棒土负载壳聚糖吸附剂对鱼油中重金属离子吸附条件研究

采用凹凸棒土负载壳聚糖吸附剂对鱼油中的竞争体系下的重金属进行吸附试验。探讨了竞争体系下吸附剂的吸附效果,分析了镉离子与铜离子的固液比、吸附温度、吸附时间和pH值对吸附性能的影响,并采用L9（34）正交实验设计对吸附条件进行优化,其最佳的组合条件为固液比值为2 g/L,吸附温度为40℃,吸附时间为80 min,pH值为8,此时镉离子和铜离子吸附率达到最大值可达到80.52%和90.21%。     

Loosening of plant cell walls by expansins

Plant cell walls are the starting materials for many commercial products, from lumber, paper and textiles to thickeners, films and explosives. The cell wall is secreted by each cell in the plant body, forming a thin fibreglass-like network with remarkable strength and flexibility. During growth, plant cells secrete a protein called expansin, which unlocks the network of wall polysaccharides, permitting turgor-driven cell enlargement. Germinating grass pollen also secretes an unusual expansin that loosens maternal cell walls to aid penetration of the stigma by the pollen tube. Expansin's action has puzzling implications for plant cell-wall structure. The recent explosion of gene sequences and expression data has given new hints of additional biological functions for expansins.     

Effects of copper content on microstructure and mechanical properties of open-cell steel foams

The effects of copper content on the microstructural and mechanical properties of steel foams are investigated. Spherical urea granules, used as a water-leachable space holder, were coated with a mixture of iron, ultrafine carbon, and different amounts of copper powders. After the mixture was compacted and the space holder was removed by leaching, a sintering process was performed under an atmosphere of thermally dissociated ammonia. Microstructural evaluations of the cell walls were carried out using optical microscopy and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy. In addition, compression tests were conducted to investigate the mechanical properties of the manufactured steel foams. The results showed that the total porosity decreases from 77.2% to 71.9% with increasing copper content in the steel foams. In the foams' microstructure, copper islands are mostly distributed in pearlite and intergranular carbide phases are formed in the grain boundaries. When the copper content was increased from 0 to 4 wt%, the elastic modulus, plateau stress, fracture stress, and fracture strain of manufactured steel foams improved 4.5, 6, 6.4, and 2.5 times, respectively.     

用微珠涡流法破壁酵母细胞

针对酵母等真菌类细胞破壁困难的问题,提出了微珠涡流破壁酵母细胞的新方法.采用该法对酵母细胞进行破壁,破壁率高达95.28%.新方法对设备要求低,简便易行,适用于实验室的研究工作.此外,该方法还可以进一步推广应用于其他类真菌细胞的破壁.     

＂Steiner trees＂ between cell walls of sisal

Through careful analysis on the cross-section of sisal fibers, it is found that the middle lamellae between the cell walls have clear geometric characteristics： between the cell walls of three neighboring cells, the middle lamellae form a three-way junction with 120° symmetry. If the neighboring three-way junctions are connected, a network of Steiner tree with angular symmetry and topological invariability is formed. If more and more Steiner trees are connected, a network of Steiner rings is generated. In another word, idealized cell walls and the middle lamellae are dominated by the Steiner geometry. This geometry not only depicts the geometric symmetry, the topological invariability and minimal property of the middle lamellae, but also controls the mechanics of sisal fibers.     

苯三甲酸和盐酸胍为主体晶格管状包合物的晶体结构

合成了苯三甲酸和盐酸胍共同构建主体晶格的正四丁基铵阳离子管状包合物(C4H9)4N+·2C(NH2)+3·1,3,5-C6H3(COO-)3·3H2O,并通过单晶X射线衍射法对其进行了晶体结构测定。结果表明:包合物中苯三甲酸阴离子和盐酸胍阳离子氢键连接形成的宽链借助水分子氢键连接在一起,形成沿bc平面无限延伸的二维氢键褶皱层,构成类长方形管道的一对管壁,另一盐酸胍阳离子穿插在氢键层中,构成管道的另一对管壁,每个管道内包含两列规则排列的正四丁基铵阳离子(n-C4H9)4N+。     

不同生境下30种藓类植物茎的比较解剖学研究

使用石蜡切片法,对采自不同生境下的30种藓类植物茎的横切面进行了比较解剖学研究.结果表明:(1)30种藓类植物茎的形状、细胞形状、表皮层数及厚度、皮部是否分化及细胞层数、中轴有无形状以及所占比例等特征因种类不同而差异明显;(2)不同水分环境下藓类植物茎的解剖结构表现出不同的特征:旱生环境下的藓类植物,茎表皮细胞排列紧密、细胞壁强烈增厚或增厚明显,有的具内外皮部分化并且外皮部细胞胞壁增厚;荫湿环境下的藓类植物,其茎表皮细胞多圆形或椭圆形、胞壁稍增厚,表皮及外皮部细胞层数比旱生环境下的藓类植物少;水生环境下的藓类植物,细胞胞壁薄,表皮细胞排列不紧密,茎皮部无内外皮部分化.表明藓类植物茎的表皮及外皮部细胞层数、细胞壁厚度与生境的相关性较大.     

LTRPC7 is a Mg.ATP-regulated divalent cation channel required for cell viability

The molecular mechanisms that regulate basal or background entry of divalent cations into mammalian cells are poorly understood. Here we describe the cloning and functional characterization of a Ca2+- and Mg2+-permeable divalent cation channel, LTRPC7 (nomenclature compatible with that proposed in ref. 1), a new member of the LTRPC family of putative ion channels. Targeted deletion of LTRPC7 in DT-40 B cells was lethal, indicating that LTRPC7 has a fundamental and nonredundant role in cellular physiology. Electrophysiological analysis of HEK-293 cells overexpressing recombinant LTRPC7 showed large currents regulated by millimolar levels of intracellular Mg.ATP and Mg.GTP with the permeation properties of a voltage-independent divalent cation influx pathway. Analysis of several cultured cell types demonstrated small magnesium-nucleotide-regulated metal ion currents (MagNuM) with regulation and permeation properties essentially identical to the large currents observed in cells expressing recombinant LTRPC7. Our data indicate that LTRPC7, by virtue of its sensitivity to physiological Mg.ATP levels, may be involved in a fundamental process that adjusts plasma membrane divalent cation fluxes according to the metabolic state of the cell.     

大孔阳离子交换树脂治理实验室废水中铜和铅的研究

研究了大孔型阳离子交换树脂治理含铜和铅的实验室废水.在试验过程中对三种阳离子交换树脂进行筛选,讨论了流速、废水的起始pH值、温度、树脂再生次数对各重金属离子去除效果的影响.在确定的最佳试验条件下,处理实际实验室废水中的铜和铅时,去除率均达到99%以上.     

天然棉纤维表面超微结构及其变化的定量分析

天然棉纤维为异质性生物大分子，其超分子结构复杂. 通过对棉纤维细胞壁横切面的微观分析，发现其结构单元主要是微纤丝，异质性棉纤维超分子结构主要是微纤丝聚集排列方式的变化造成的. 利用原子力显微镜（AFM）对棉纤维表面立体结构的直接观察分析也进一步确证微纤丝聚集排列方式的多样性. AFM获得的结构图像是三维立体的，其起伏变化的指标——表面粗糙度，能够定量地表征棉纤维表面超微结构（微纤丝交叉区与平行区）及其降解过程中的变化程度. 对比X光衍射（XRD），红外光谱（FTIR）等跟踪棉纤维结构的变化结果，AFM对表面超微结构的分析能够在更深层次上反映具体结构的变化规律，从而为解决异质性的纤维素超分子结构与酶解效率之间定量关系的研究奠定了基础.     

pH induced elastic modulus of guard cell wall in stomatal movement

Guard cell wall properties are important in stomatal movement. Previous research focused on the structure and anatomy of guard cell walls, but little is known about the physical changes that take place within the walls during stomatal opening and closure. In this work, we investigate the volumetric elastic modulus (ε) of the guard cell wall at different pH values during stomatal opening in Vicia faba epidermal strips using a cell pressure probe. The volumetric elastic modulus of the guard cell wall decrease...