温度和酸碱度对金黄色葡萄球菌生长对数期的影响

通过改变培养温度和培养液的酸碱度,绘制金色葡萄球菌在不同p H值和温度条件下的生长曲线,探索和总结在不同条件下的生长繁殖规律,以期更有效地利用和控制金色葡萄球菌对数期的生长,结果显示,升高培养温度和提高培养液酸碱度都能缩短金色葡萄球菌生长曲线对数期,但p H值=8.4时R2=0.9254大于p H值=7.4时R2=0.8638,故提高培养液酸碱度得到的对数期更平稳。     

草炭水溶解态有机质与金属离子络合稳定常数的测定

采用离子交换平衡法测定草炭水溶解态有机质与Cu^2＋、Pb^2＋、Zn^2＋、Cd^2＋4种金属离子的络合稳定常数。试验在两种不同PH值条件下进行，试验结果表明，金属离子与草炭水溶解态有机质通常形成混合或多核络合物；在两种不同PH值条件下的络合配位数和稳定常数序列均为：Cu^2＋〉Pb^2＋〉Zn^2＋〉Cd^2＋，高PH值条件下，络合配位数和稳定常数均明显增大。     

内秦淮河逸仙桥处沉积物中镉吸附与释放及形态转化研究

通过研究不同环境条件对镉在内秦淮河逸仙桥处沉积物中的吸附与释放及形态转化规律的影响,发现吸附量和释放量都随温度升高而增大;吸附量随pH值增大而增大、随盐度增大而减小;pH值改变对沉积物中镉形态的影响较小。盐度增大,镉的生物有效性降低。镉释放量随pH值增大而减少、随盐度增大而增大。在不同环境条件下,沉积物中镉达最大释放量时释放的形态不同,pH值为5时,释放镉以碳酸盐结合态为主,由20.67%降至2.1%;盐度为10%时,释放镉以有机结合态为主,由15.24%降至6.32%;温度为30℃时,以可交换态为主,由16.48%减少至1.6%。     

表面活性剂对聚团石英颗粒的沉降效果研究

为探讨表面活性剂作用下石英颗粒的沉降特性,本文以石英颗粒为研究对象,选取4种季铵盐(HTC27、CFS1、ESD5、ZT7K)并配置不同浓度和不同pH值的溶液,研究其对石英颗粒的沉降效果,分析了上清液的透光率、沉淀产率以及Zeta电位值,结果表明:(1)HTC27季铵盐在浓度为15 mol·L~(-1)对石英颗粒的沉淀效果最好、Z17K为6mol·L~(-1)、ESD5为9mol·L~(-1)、CFS1为3mol·L~(-1);(2)随HTC27和ZT7K季铵盐浓度的增加沉降产率逐渐增大,在CFS1季铵盐作用下随pH值的增大上清液透光率先增大后减小,随ESD5季铵盐浓度的增大上清液透光产率先增大后减小,浓度为12mol·L~(-1)时对应的沉降产率达到最大值57.3%。(3)HTC27和CFS1季铵盐在溶液pH值为7时,对石英颗粒的沉降效果最好;ZT7K季铵盐溶液pH值为3时,对石英颗粒沉降效果最好,ESD5季铵盐溶液pH值为11时,对石英颗粒沉降效果最好;(4)石英颗粒表面电位在4种类型的季铵盐作用下均是随浓度的增大而增大,且均是先快速增大后平稳增长或保持不变。     

pH值对L-抗坏血酸与L-脯氨酸/L-丙氨酸Maillard反应产物抗氧化活性的影响

在L-抗坏血酸-L-脯氨酸/L-丙氨酸模型体系中研究了pH值对Maillard反应产物的抗氧化活性的影响。Maillard反应产物通过控制不同初始pH值（pH=4.0、5.0、6.0、7.0、8.0）在140 ℃下加热搅拌2h的条件下制备,并以还原力、1,1-二苯基-2-苦基偕腙肼自由基（DPPH）清除能力和Fe2 螯合能力为指标对其产物抗氧化活性进行分析评价。结果表明：产物的还原力、DPPH自由基清除能力在pH=5时达到最大,Fe2 螯合能力随着pH值的增大而增大,而且Maillard反应产物的还原力与在294nm处的紫外吸光度密切相关。     

GPC法测水溶性沥青的分子量分布

为了探讨凝胶渗透色谱法(GPC)测定水溶性沥青平均分子量及其分布,本文以中温煤沥青为原料,采用混酸氧化-碱溶-酸沉法制备了不同PH值沉降的水溶性沥青;以四氢呋喃为洗脱液,GPC法测平均分子量及其分布。结果表明:本文工艺条件下制备的水溶性沥青需要不同范围的GPC柱的组合才能准确高分辨率测定;在水溶性沥青制备过程中对分子量影响最显著的因素是沉降过程中的PH值,分子量小于1000的组分在PH为12-6的样品中占53.06%,在PH为6-4的样品中占23.89%,在PH为4-2的样品中占18.68%,可见制备水溶性沥青时沉淀PH越小,所得产品的分子量越大。说明分子量大的分子不仅可溶于碱性溶液也能溶于酸性溶于,而分子量小的分子只溶于碱性溶液,不溶于酸性溶液。     

暴露和浸泡混凝土氯离子结合能力相关性研究

在盐湖现场暴露和长期浸泡环境下进行了混凝土腐蚀试验,分别测定了不同试验环境下混凝土构件在不同深度的总氯离子含量(Ct)和自由氯离子含量(Cf),运用了回归法分析盐湖卤水浸泡和盐湖现场暴露环境下混凝土氯离子结合能力的相关性系数KR与其扩散深度、混凝土抗压强度的相关性.分析结果表明:氯离子结合能力相关性系数KR随着混凝土抗压强度的增加而降低;对于混凝土抗压强度小于58.6 MPa时,其KR值均大于1.2且随着氯离子扩散深度的增加而增大,当混凝土抗压强度为80.6 MPa时,其KR值仅为0.8且随着氯离子扩散深度的增加而降低.因此,为了更准确的预测盐湖现场环境下的实体结构的寿命,需要利用RE=2.687e-0.0142fc+(0.0111-0.0002fc)xRI将室内环境下的氯离子结合能力换算成现场环境下的氯离子结合能力.     

化妆品基础环境对β-熊果苷稳定性的影响

熊果苷是美白和祛斑作用的化妆品中最为广泛使用的美白剂之一。选取β-熊果苷为研究对象,改变化妆品的温度和pH值,对β-熊果苷的稳定性进行讨论。同时,采用紫外分光光度法测定β-熊果苷在不同浓度和不同基础环境下分解产物含量。实验结果表明,温度为30℃~40℃,质量分数为0.2%~1.0%时,β-熊果苷相对稳定。反应温度高于50℃时,β-熊果苷溶液的分解趋势曲线陡增,可分析50℃为β-熊果苷的极限分解温度;β-熊果苷在中性及偏酸性的pH条件下相对稳定,在酸性(pH4)或碱性(pH9)的环境下易分解。并由此进一步确定适用于美白和祛斑类化妆品的体系的温度和酸碱度。     

PAC-PDMDAAC处理微污染水的絮凝特征研究

采用无机-有机复合絮凝剂PAC-PDMDAAC处理微污染水,考察了PAC与PDMDAAC质量比、PACPDMDAAC投加量对浊度和溶解性有机物去除效果的影响,利用絮凝度测定仪(PDA)在线监测絮凝过程,分析了不同pH、不同搅拌条件下的FI指数、分形维数的絮凝特征变化规律。实验结果表明,PAC与PDMDAAC的最佳质量比为5∶1,PAC-PDMDAAC最佳投加量为30 mg/L,最佳pH为5.0。当快搅强度为100 r/min时,FI曲线的平衡值最大,絮凝效果最佳;当快搅时间为1 min时,分形维数随快搅强度的增大而增大;当快搅时间分别增加至2 min和3 min时,分形维数随快搅强度的增大而减小。     

硫酸盐还原菌的生长影响因子及脱硫性能的研究

采用单因素法研究从硫酸厂淤泥厌氧菌群中分离筛选的硫酸盐还原菌(SRB),分析生物脱硫过程中影响SRB生长及其还原硫酸盐性能的主要因素。结果表明,分离获得的SRB的菌体呈弧状或细杆状,初步鉴定为脱硫弧菌属细菌。该菌是典型的嗜中温菌,培养与应用转化时均以35℃最为适宜,生长环境酸碱度范围较宽,最适宜范围为pH 6.0~6.5;是非严格厌氧型菌,适量氧气不会影响细菌生长。SRB在COD/SO42-质量比值达到2.0~2.5时,培养与应用转化时的最适宜温度为35C,以含有醇羟基的有机碳作为有效的电子供体,以SO42-作为电子受体,4天左右即可对生长环境、脱除烟气中SO2后的垃圾渗沥液中COD、SO42-进行较好的转化还原, SO42-转化能力可达1800mgL-1。     

Probiotics,fact or fiction

Eight bacterial strains utilizing glucoisosaccharinic acid (GISA), which is one of the main components of sulphate black liquor hydroxyacids, were isolated from the environment of a sulphate pulp mill. The best GISA-utilizing bacterium was isolated from soil and it was identified as Micrococcus lylae. The growth of M. lylae on GISA in the pH range 5.0–9.0 was studied, optimum growth and utilization of GISA being observed at pH 8.0. M. lylae also utilized D,L-lactic acid and black liquor separated from the lignin.     

Identification of Genomic Regions Associated with Vine Growth and Plant Height of Soybean

Vining growth (VG) and high plant height (PH) are the physiological traits of wild soybean that preclude their utilization for domesticated soybean breeding and improvement. To identify VG- and PH-related quantitative trait loci (QTLs) in different genetic resources, two populations of recombinant inbred lines (RILs) were developed by crossing a cultivated soybean, Zhonghuang39 (ZH39), with two wild soybean accessions, NY27-38 and NY36-87. Each line from the two crosses was evaluated for VG and PH. Three QTLs for VG and three for PH, detected in the ZH39 × NY27-38 population of the RILs, co-located on chromosomes 2, 17 and 19. The VG- and PH-related QTL in the ZH39 × NY36-87 population co-located on chromosome 19. A common QTL shared by the two populations was located on chromosome 19, suggesting that this major QTL was consistently selected for in different genetic backgrounds. The results suggest that different loci are involved in the domestication or adaptations of soybean of various genetic backgrounds. The molecular markers presented here would benefit the fine mapping and cloning of candidate genes underlying the VG and PH co-localized regions and thus facilitate the utilization of wild resources in breeding by avoiding undesirable traits.     

天然胶乳／甲酸／过氧化氢混合物的酸度效应

研究了天然胶乳／甲酸／过氧化氢混合物的酸度效应,探讨了混合物的酸度与其组成及停留时间的关系。结果表明,过氧化氢可使pH＝2．0的天然胶乳－甲酸混合物的pH值显著下降,对于pH＝2．0的天然胶乳／甲酸／过氧化氢混合物,随着停留时间的推移,体系的pH值在初期发生显著的下降,随后又上升并超过初始pH值。天然胶乳／甲酸／过氧化氢混合物所表现的上述酸度效应是混合物中所含天然橡胶、甲酸和过氧化氢之间相互作用和反应情况的综合体现。     

光催化氧化去除水中腐殖酸

光催化氧化法对水中腐殖酸有很强的氧化能力，可将其完全氧化为ＣＯ２等简单无机物。该方法对ＰＨ和温度的适应范围广，无需曝气充氧也有很好的处理效果，很有希望实用于纯水的制备。     

聚中性红修饰玻碳电极的制备及应用

通过循环伏安法(CV)对聚中性红修饰玻碳电极的制备方法进行了研究,同时研究了谷氨酸在聚中性红修饰玻碳电极上的电化学行为。结果表明,聚中性红修饰玻碳电极对谷氨酸有明显的伏安响应,在电位范围为-0.8~0V、扫描速率为100mV·s-1的条件下,谷氨酸在该修饰电极上产生一对氧化还原峰,谷氨酸在5.0×10-6~2.0×10-4mol·L-1浓度范围内与峰电流呈良好的线性关系,检出限(S/N=3)为2.0×10-6 mol·L-1。据此,建立了谷氨酸的电化学分析方法。     

Characterization of Vanaspati Fat Produced in Iran

Vanaspati is the main culinary fat consumed in Iran. It is produced from vegetable oils using different modification processes such as hydrogenation, fractionation, interesterification or blending. To characterize this product, samples from different Iranian brands were collected and their physicochemical properties were studied. Iranian vanaspati contains 0.3–6.2 % trans fatty acids and 24.8–30.5 % saturated fatty acids. Linoleic acid with a range of 32.5–40.3 % is the main unsaturated fatty acid of vanaspati. Iodine values and saponification values of the samples were in the range of 91.9–106.4 and 193.2–194.3, respectively. Free fatty acid contents between 0.04 and 0.10 % and peroxide values between 2.0 and 8.8 mequiv/kg were detected in samples. The induction period of oxidation of the samples was found to be between 8.5 and 15.4 h at 110 °C. With an average slip melting point of 32.9 °C, samples contained 10.0–22.6 % solid fat content at 10 °C, 4.2–10.6 % at 20 °C, 0.3–5.2 % at 30 °C and 0.0–0.5 % at 40 °C. The induction period of crystallization and crystallization rate of samples, were in the range of 0.0–33.11 min and 0.07–2.54 1/min, respectively. Lovibond red and yellow color indices of the product were found to be in the range of 5.0–7.3 and 69.5–70.2, respectively.     

掺磷中孔SiO_2在30℃～200℃范围内的质子导电性

合成了孔壁掺磷中孔SiO2(m-PH-SiO2),其BET比表面积为407m2g-1,BJH平均孔径为6.1nm。用交流阻抗技术测定了除去游离P2O5的掺磷中孔SiO2在30℃～200℃范围内100%相对湿度下的质子电导,样品导电率随温度升高而升高,在150℃和100%相对湿度下,样品的电导可达3.1×10-3S·cm-1,比纯中孔SiO2(m-SiO2)的电导约高一个数量级,原因是m-PH-SiO2的物理吸附水量为31个分子/nm2,而m-SiO2只有24个分子/nm2。     

Fabrication and characterization of electrospun psyllium husk-based nanofibers for tissue regeneration

The present study reports for first time the blending of psyllium husk (PH) powder/gelatin (G) in the polymer-rich composition of polyvinyl alcohol (PVA) to make an electrospinnable solution. The composite was prepared in 3 different ratios viz., 100% (wt/wt) (PVA + PH), 75% + 25% (PVA + 75PH + 25G) (wt/wt) and 50% + 50% (PVA + 50PH + 50G) (wt/wt) in 6% PVA solution. Optimum electrospinning parameters were evaluated for all the prepared blends. The fabricated nanofibers were characterized by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared, differential scanning calorimetry, porosity percentage, and fiber orientation using ImageJ software. A qualitative in vitro degradation study at room temperature is supported by SEM images. The cellular interactions were characterized by MTT assay of NIH-3T3 fibroblast cells for 2 and 4 days with an optimum cell growth of >50% by fourth day of culture and long-term cultivation of L929-RFP cells was observed for 10 days. The nanofibers were formed in the range of 49–600 nm. PVA + 75PH + 25G when cultured with L929-RFP cells exhibited highest fluorescence intensity and thus supported cellular proliferation significantly. Based on the results obtained from various analyses, we anticipate that fabricated psyllium-based nanofiber can be used as a promising candidate for wound healing and other biomedical applications.     

Synthesis and characterization of poly(ethylene glycol)-b-poly(l-histidine)-b-poly(l-lactide) with pH-sensitivity

In this paper, amphiphilic biodegradable methoxy-poly(ethylene glycol)-poly(l-histidine)-poly(l-lactide) (mPEG–PH–PLLA) triblock copolymers with pH sensitivity were synthesized. The properties of mPEG–PH–PLLA triblock copolymers were investigated by GPC, ¹H NMR, DSC, TGA, XRD and polarized optical microscopy. The results showed that the thermal properties of the triblock copolymers varied with the chain length of PH blocks. The glass transition temperatures (Tg) of the triblock copolymers increased with increasing poly(l-histidine) chain length. The morphologies of PLLA crystals changed from spherulite to dendritic crystal. Moreover, the crystallization rate of triblock copolymers was faster than that of PLLA homopolymer. The pH sensitivity of the self-assembled mPEG–PH–PLLA nanoparticles was investigated. The mean diameter and morphology of the nanoparticles were characterized by DLS, AFM and TEM. The results showed that the mean diameter of mPEG₄₅–PH₃₀–PLLA₈₂ nanoparticles in pH = 5.0 was smaller than that in pH = 7.4.     

基于PLC污水处理厂的pH值自动控制系统设计与研究

采用西门子S7-300 PLC为功能核心,组态王(King View 6.55)软件提供上位监控功能,PID (比例-积分-微分)表和PD (比例?微分)表相结合的控制方式,实现对污水中和池pH在适当范围的控制。所设计系统满足污水厂中和池pH在相应范围控制的要求,监控方便,可靠性好。