Effect of Silver Particle size on color and Antibacterial properties of silk and cotton Fabrics

In this study silver nanoparticles with different particle sizes and hence colors were synthesized on silk and cotton fabrics through reduction of silver nitrate. Particle sizes of the silver colloids were measured by dynamic light scattering (DLS). The structure and properties of the treated fabrics were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and UV-Vis reflectance spectroscopy. Various characteristics of the treated fabrics including antibacterial activities against a Gram positive (Staphylococcus aureus) and a Gram negative (Escherichia coli) bacteria, color effect, wash and light fastness, water absorption, fabric rigidity, and UV blocking properties were also assessed. The results indicated that the treated fabrics displayed different colors in the presence of silver nanoparticles with different particle sizes and exhibited good and durable fastness properties. Also, the size of the silver particles had a tangible effect on antibacterial activity of treated fabrics and its antibacterial performance was improved by decreasing the size of particles. Moreover, this process imparted significantly UV blocking activity to fabric samples.     

玉米淀粉糖纳米纤维的制备及性质表征

采用高压静电纺丝法制备柠檬酸酯化交联的玉米淀粉糖的纳米纤维。通过扫描电镜可以看出,该方法可直接获得具有较好结构的玉米淀粉糖纳米纤维。经过70℃的热处理后,纤维的刚性降低,韧性增强,形貌可长时间保持不变。红外光谱和X-射线粉末衍射显示,玉米淀粉糖与柠檬酸发生了酯化交联反应。从纤维直径分布图中可以看出,柠檬酸含量增加,纤维直径变小,纤维均匀程度有所提高。     

Facile Fabrication of Durable Antibacterial Cotton Fabric Realized by Thioglycolic Acid and Silver Nanoparticles

In this study, durable antibacterial cotton fabrics were prepared by a simple two-step impregnation method. Firstly, thioglycolic acid (TGA) was grafted onto cotton fabric via esterification with the hydroxyl groups of cellulose, then silver nanoparticles (Ag NPs) were immobilized on the cotton fabric surface via coordination bonds with the TGA thiol groups. As a result, the mean size of Ag NPs coating on the cotton fabric is around 74 nm, and these functionalized cotton fabrics show superior antibacterial properties and excellent laundering durability. After withstand 50 laundering cycles, the obtained cotton fabrics still showed outstanding bacterial reduction rates (BR) against both S. aureus and E. coli, and the rates are all higher than 97 %. Therefore, this method to prepare antibacterial cotton fabric shows great potential applications in socks, cosmetic, and medical textiles.     

Preparation and Properties of Nylon 4/6 Copolymer Nanofibers Containing Silver-Zeolite Nanoparticles

Nylon 4/6 copolymer has desirable properties, such as high affinity to water and good tensile strength. These properties originate from the characteristics of nylon 4 and nylon 6. Zeolite is a good adsorptive material that has many pores in its structure and the ability to capture metallic ions. As a multifunctional additive, silver-ion-loaded zeolite nanoparticles were used to increase the moisture regain and impart antimicrobial properties to the nylon 4/6 copolymer. A nylon 4/6 nanofiber web was prepared by electrospinning from a polymer solution containing silver zeolite nanoparticles. The moisture regain of the nylon 4/6 nanofiber web increased with increasing amount of silver zeolite added. The web showed excellent antimicrobial activity against Klebsiella pneumoniae and Staphylococcus aureus. Overall, the nylon 4/6 nanofiber web could be a good material for wound healing dressings and high functional medical filters.     

Leveraging the Antibacterial Properties of Knitted Fabrics by Admixture of Polyester-Silver Nanocomposite Fibres

Leveraging the antibacterial properties of polyester-cotton knitted fabrics has been attempted in this research by admixture of small proportion of polyester-silver nanocomposite fibres. Polyester-cotton (50:50) yarns were spun by mixing 10, 20 and 30 % (wt.%) polyester-silver nanocomposite fibres with normal polyester fibres so that overall proportion of polyester fibre becomes 50 %. The proportion of cotton fibre was constant (50 %) in all the yarns. Three parameters, namely blend proportion (wt.%) of nanocomposite fibres, yarn count and knitting machine gauge were varied, each at three levels, for producing 27 knitted fabrics. Polyester-cotton knitted fabrics prepared from polyester-silver nanocomposite fibres showed equally good antibacterial activity (65-99 %) against both S. aureus and E. coli bacteria. Antibacterial properties were enhanced with the increase in the proportion of polyester-silver nanocomposite fibres, yarn coarseness and increased compactness of knitted fabrics. Yarn count and blend proportion of nanocomposite fibre were found to have very dominant influence in determining the antibacterial properties of knitted fabrics.     

Antibacterial Coating of Glass Fiber Filters with Silver Nanoparticles (AgNPs) and Glycidyltrimethylammonium Chloride (GTAC)

Silver nanoparticles (AgNPs) were attached to glass fiber filters to improve their antibacterial properties using glycidyltrimethylammonium chloride (GTAC), a type of quaternary ammonium salt. The glass fiber filters treated with GTAC were placed into the Ag colloid and heat-treated at 43 °C for 90 min to attach AgNPs to the glass fiber filters. The glass fiber filters with the attached AgNPs were then analyzed by scanning electron microscopy and atomic force microscopy (AFM). The surface morphology of the glass fiber filters treated with GTAC and AgNPs was observed. The Ag atomic % of the glass fiber filters was analyzed according to the GTAC concentration, Ag colloid concentration, and AgNPs treatment temperature. The surface roughness of the glass fiber filters with the attached AgNPs was measured by AFM. The antibacterial tests of the GTAC and AgNP-treated glass fiber filters highlighted the sufficient antibacterial effects against E. coli, S. aureus, and P. aeruginosa. In particular, the antibacterial properties of glass fiber filters against S. aureus and P. aeruginosa were improved when the glass fiber filters were treated with both GTAC and AgNPs.     

华南荔枝园土壤性质调查与分析

采集华南荔枝主产区荔枝园土壤样本470个,根据第二次全国土壤普查土壤养分分级指标对土壤性质进行评价,并对各产区土壤性质进行对比,进一步探讨土壤性质之间的关系。结果表明,华南荔枝园土壤普遍酸性强,90%以上果园土壤为酸性和强酸性。土壤阳离子交换量整体处于低水平,保水保肥能力弱。土壤有机质、碱解氮、速效钾及有效钼含量处于中低水平,交换性钙和镁及有效硼处于低水平,而有效磷、有效锌含量适中,有效硫和有效铜含量丰富。整体上荔枝园土壤养分肥力偏低且不均衡。不同产区土壤养分肥力差异较大。海南产区土壤有机质、碱解氮、有效磷和有效锌含量最高;云南产区速效钾、交换性钙、交换性镁、有效铜含量明显高于其他产区,而有机质、有效磷、有效硫、有效钼含量最低;广东产区则土壤有效硼含量最高。Pearson相关分析结果显示,土壤多种性质之间关系密切。其中,pH和交换性钙、交换性镁均呈极显著正相关关系（P<0.01）;交换性钙和交换性镁之间,有效铜和有效锌之间,速效钾与交换性钙之间均为极显著正相关（P<0.01）。针对华南荔枝园土壤酸性强及养分不均衡的问题,建议重视土壤pH改良,加强有机肥的施用,合理施用氮、磷、钾肥,并增加钙、镁、硼肥。     

抑菌剂抑菌效果及对马铃薯试管苗生长发育的影响

为降低马铃薯组培污染,试验采用多菌灵、盐酸万古霉素、制霉菌素、益培隆和冰片5种抑菌剂,开展不同浓度处理对青霉菌、黑曲霉、细菌抑制效果比较及其对马铃薯试管苗生长发育的影响试验。结果表明,冰片与益培隆浓度分别达20和50 mg/L时,对青霉菌的抑制率达100.0%;冰片、益培隆和制霉菌素浓度分别达50,80和80 mg/L时,对黑曲霉的抑制率达100.0%;冰片、益培隆和盐酸万古霉素浓度分别达20,50和80 mg/L时,对细菌的抑制率达100.0%;5种抑菌剂浓度为20 mg/L时,对试管苗生长发育及成活率均无任何影响,当浓度增大到80 mg/L时,对试管苗生长发育均有抑制作用。     

Superhydrophobic and Antibacterial Properties of Cotton Fabrics Treated with PVDF and nano-ZnO through Phase Inversion Process

Cotton fabrics exhibiting superhydrophobic and antibacterial properties were prepared through a non-solvent induced phase separation method using hydrophobic poly(vinylidene fluoride) (PVDF) and its hybrids with photocatalytic zinc oxide nanoparticles (nano-ZnO) as surface modifying agents for cotton fabric. The effects of coagulating medium and temperature on microstructural morphology and surface hydrophobictity of the cotton fabrics were investigated by FE-SEM observation and contact angle measurement. Superhydrophobic cotton fabrics exhibiting water contact angle higher than 150 ° could be obtained by coating the fabrics with solutions of PVDF and nano-ZnO followed by coagulation in ethanol as non-solvent. This phenomenon is considered to be originated from both chemically hydrophobic PVDF layer and physical micro- and nano-bumps formed on the surface of cotton fabric, which are essential requirements for Lotus effect. Moreover, antibacterial properties could be synergistically obtained by utilizing photocatalytic effect of nano-ZnO.     

Influence of Poly(lactic acid) Layer on the Physical and Antibacterial Properties of Dry Bacterial Cellulose Sheet for Potential Acute Wound Healing Materials

Dry bacterial cellulose nanofiber (BC) sheet coated with poly(lactic acid) (PLA) was developed and characterized towards acute wound healing applications. This new approach of PLA coating on BC revealed enhanced physical and antibacterial properties. Commercial BC sheets originated from the manufacturing of nata de coco jelly were dried and coated with the PLA at various concentrations of 2, 4, 6, 8, 10 and 12 % w/v for the purpose of improving the mechanical properties and followed by loading of antiseptic such as benzalkonium chloride (BAC). PLA has been proposed for the use of coating materials at a concentration of 8 %, the biocomposite sheet started exhibiting a low moisture uptake, prolonged swelling in simulated wound fluid solution and high tear (9.17 Nm²/kg) and burst indices (32.5 kPa·m²/g). The 8 % PLA coating revealed porous fiber-like morphology as observed under scanning electron microscope. Therapeutic loading capacity of the BC/8 PLA was substantially higher than the pristine BC. Furthermore strong antimicrobial activities against Staphylococcus aureaus and Escherichia coli were observed for the BC/8PLA biocomposite film. These reports were clearly suggestive of the fact that synthetic biodegradable polymers, such as PLA, may be exploited for the synergistic combination with BC for antimicrobial and acute wound management. This new and modified fiber source material could reduce the dependency on plant based cellulose for more demanding biomedical applications such as wound healing materials, vascular graft, cartilage replacement, drug delivery and tissue engineering.     

一种高效省本的非变性聚丙烯酰胺凝胶电泳银染法的建立——以水稻为例

非变性聚丙烯酰胺凝胶电泳银染技术已广泛用于DNA片段检测。介绍一种本实验室改进的高效省本的非变性聚丙烯酰胺凝胶电泳银染方法,该法将固定和染色两步骤合并,整个银染过程只需16 min即可完成。同时,该法无需使用无水乙醇和冰乙酸,减少了硝酸银、氢氧化钠及甲醛的使用量。     

云南野生稻资源考察及分布现状分析

利用现有资料,采用当地人员参与性考察调查方法,在2002年10月和2003年3月对云南省玉溪市、思茅地区、西双版纳傣族自治州、德宏傣族景颇族自治州、保山地区和临沧地区16个县（市）的93个野生稻原生境进行了考察核查。发现原先记载的93个野生稻分布点中只有30个点还存在野生稻,同时又发现了10个疣粒野生稻新分布点。现存野生稻分布点合计40个,其中普通野生稻1个点、药用野生稻2个点和疣粒野生稻37个点。这40个野生稻点分布于6个地区（州、市）16个不同的县（市）,其中35个点集中分布在思茅地区、临沧地区和德宏傣族景颇族自治州12个县（市）。普通野生稻分布点的面积约1 334 m2,2个药用野生稻分布点的面积均约为334 m2,37个疣粒野生稻分布点的面积变幅较大,从少量几丛到133 400 m2以上;分布面积不少于13 340 m2且密度在中等以上的分布点全省只有8个,这8个点中有4个分布在思茅地区的普洱县、墨江哈尼族彝族自治县和思茅市,2个点分布在德宏傣族景颇族自治州的龙陵县,还有临沧地区的沧源佤族自治县和西双版纳景洪市各有1个分布点。     

基于植物多样性的杭州市道路路侧绿地植物配置浅析

采用抽样调查方法对杭州市区道路绿化进行调查,统计分析杭州市道路路侧绿地的物种组成、群落丰富度、群落盖度及植物多样性组成.并针对调查结果,对城市道路路侧绿地绿化现状及存在的问题提出建议和对策.     

金线莲乙醇提取物对金黄色葡萄球菌抑菌性能研究

用乙醇作为溶剂,提取出金线莲中的有效抑菌物质,采用二倍稀释法确定金线莲乙醇提取物对金黄色葡萄球菌的最小抑菌浓度(Minimal inhibition concentration,MIC)为5.000 mg/m L;并经介质pH、热处理和紫外线处理提取物,发现其抑菌圈直径在pH9.0和30℃下最大;分析金线莲乙醇提取物对供试菌蛋白质和还原糖的利用能力,表明金线莲乙醇提取物通过减弱蛋白质和还原糖的代谢来抑制细菌的生长繁殖。     

Comparative Analysis of the Functional Properties of Films Based on Carrageenans,Chitosan, and Their Polyelectrolyte Complexes

The influence of the structural features of carrageenan on the functional properties of the films was studied. The carrageenans and chitosan films, as well as three-layer films containing a polyelectrolyte complex (PEC) of the two, were prepared. The X-ray diffractograms of carrageenan films reflected its amorphous structure, whereas chitosan and three-layer films were characterized by strong reflection in the regions of 20° and 15° angles, respectively. The SEM of the cross-sectional morphology showed dense packing of the chitosan film, as well as the layer-by-layer structure of different densities for the PEC. Among the tested samples, κ/β-carrageenan and chitosan films showed the highest tensile strength and maximum elongation. Films containing the drug substance echinochrome were obtained. Mucoadhesive properties were assessed as the ability of the films to swell on the mucous tissue and their erosion after contact with the mucosa. All studied films exhibited mucoadhesive properties. All studied films exhibited mucoadhesive properties which depended on the carrageenans structure. Multilayer films are stronger than single-layer carrageenan films due to PEC formation. The resulting puncture strength of the obtained films was comparable to that of commercial samples described in the literature.     

Characterization and Biocompatibility Properties In Vitro of Gel Beads Based on the Pectin and κ-Carrageenan

This study aimed to investigate the influence of kappa (κ)-carrageenan on the initial stages of the foreign body response against pectin gel. Pectin-carrageenan (P-Car) gel beads were prepared from the apple pectin and κ-carrageenan using gelling with calcium ions. The inclusion of 0.5% κ-carrageenan (Car0.5) in the 1.5 (P1.5) and 2% pectin (P2) gel formulations decreased the gel strength by 2.5 times. Car0.5 was found to increase the swelling of P2 gel beads in the cell culture medium. P2 gel beads adsorbed 30–42 mg/g of bovine serum albumin (BSA) depending on pH. P2-Car0.2, P2-Car0.5, and P1.5-Car0.5 beads reduced BSA adsorption by 3.1, 5.2, and 4.0 times compared to P2 beads, respectively, at pH 7. The P1.5-Car0.5 beads activated complement and induced the haemolysis less than gel beads of pure pectin. Moreover, P1.5-Car0.5 gel beads allowed less adhesion of mouse peritoneal macrophages, TNF-α production, and NF-κB activation than the pure pectin gel beads. There were no differences in TLR4 and ICAM-1 levels in macrophages treated with P and P-Car gel beads. P2-Car0.5 hydrogel demonstrated lower adhesion to serous membrane than P2 hydrogel. Thus, the data obtained indicate that the inclusion of κ-carrageenan in the apple pectin gel improves its biocompatibility.     

基于烟叶物理属性的烟叶出片率模型研究

为研究烟叶物理属性与出片率的定量关系,应用逐步回归、主成分回归、支持向量机回归3种方法对58个烟叶样品建立出片率预测模型.同时,采用3种预测模型对15个未知烟叶样本进行预测.结果显示:逐步回归模型预测标准偏差为1.168;主成分回归预测标准偏差为1.203;当参数c=29.744,g=0.01时,支持向量机预测标准偏差为0.624.表明采用支持向量机回归方法预测精度最高.     

Comparison of Two Methods For Determining the Discoloration Potential of Potato Tubers Based on Their Chemical and Biochemical Properties

The aim of this study was to compare the homogenization and visual methods that are used to determine the discoloration potential of potato tubers. Two German cultivars, Agria and Satina, and two Polish cultivars, Lena and Mors, were planted during 1998 and 1999 in Goettingen, Germany, and in Bydgoszcz, Poland. The discoloration potential of the tubers was measured after harvesting and after 6 months of storage at 4 C and 8 C. Both methods correlated significantly at harvest (0.709,P < 0.001). After storage the correlation was significant but low (r = 0.403,P < 0.001) probably because of physical changes in the tuber during storage. The visual method can be used as a fast method, especially at harvest. However, the homogenization and visual methods determine, to a certain degree, different tuber properties leading to the discoloration potential. Therefore, a complete comparison is not possible. The methods studied in this paper can complement but not substitute each other. Reliable comparisons between institutes require use of the same method to determine the discoloration potential of the tuber.     

糖胶树花次生代谢产物及其抗细菌活性

采用水蒸气蒸馏法提取糖胶树花挥发油,通过气相色谱-质谱联用技术(GC-MS)对挥发油进行成分分析,采用薄层层析——生物自显影法测定糖胶树花乙酸乙酯层提取物对供试细菌的抑制活性。结果表明,糖胶树花挥发油得率为0.018%,通过GC-MS分析,从中鉴定出20个成分,占挥发油总量的97.53%,其主要成分为2-莰烯(23.30%),芳樟醇(23.09%),(-)-4-萜品醇(10.54%)。糖胶树花乙酸乙酯层提取物对大肠杆菌表现出较强的抑制活性,其次为黄瓜角斑病菌,对其他供试细菌未表现出抑制活性。