固定化厌氧污泥小球的生物活性研究

本文采用间歇试验法，比较了以壳聚糖为载体、利用包埋法制备的固定化厌氧污泥小球与悬浮厌氧污泥的生物活性，结果是固定化厌氧污泥系统(IANS)的降解能力显著高于悬浮厌氧污泥系统(ANS)。     

氧化还原条件变化对上覆水体中溶解有机质的三维荧光光谱特征影响

利用三维荧光光谱(3EEMs)技术,考察了不同氧化还原条件对上覆水体中溶解有机质的三维荧光光谱特征的影响。好氧条件下上覆水体中DOM的荧光指数要高于厌氧条件,说明在不同的氧化还原条件下,上覆水体中DOM来源和组成均存在一定的差异性。上覆水体的三维荧光光谱特征也存在显著差异:好氧条件下,上覆水体中的类蛋白荧光峰强度均高于腐殖质类荧光峰强度,且三维荧光光谱图显示腐殖质类DOM存在氧化降解现象。厌氧条件下,上覆水体中腐殖质类荧光峰的强度随培养天数逐渐增加,当厌氧培养时间为21 d,C和D荧光峰的强度已分别上升至初始的3.51和3.78倍。在不同的氧化还原条件下,类蛋白和类腐殖质类DOM荧光峰位置和强度的变化,表明不同类型DOM的生物可利用性程度和在沉积物-水界面间迁移转化特征的差异性。     

采用数字信号处理的复合材料超声谱分析

在一块玻璃比例不氧树脂复合材料板的热压固化过程中，人为加进不同种类，大不及放入深度的薄膜片，并预置一定大小的裂纹，分别利用反射法和地获取回流，并对其高速采样及截取，然后进行幅度谱，相位谱，功率谱，相关谱，自相关函数及互相关函数平方包络提取的分析，获得了一些针对不同预置杂质，缺陷的特征。     

88-1型超声乳化、强化处理机(研制产品)

88-1型超声乳化、强化处理机是高强度超声处理设备，由中国科学院声学研究所研制。主要用于乳化、强化处理各类液体介质，包括超声乳化、混合、清洗、分散、破碎和强化化学反应等，系一机多用。     

超声顺磁共振的原理和应用

本文讲述了超声顺磁共振的基本原理，介绍了两种观测方法：超声吸收饱和法及超声吸收附加法；比较了超声顺磁共振法和电子顺磁共振法的差异及优缺点；扼要地介绍了超声顺磁共振法在金属、半导体和一些晶体的原子热运动、原子排布和对称性及结构缺陷等方面研究中的应用．     

镁合金稀土阻燃机理电子理论研究

通过计算机软件建立镁合金的晶体，液态及其固/液界面模型.采用递归法计算了稀土元素在α-Mg、固/液界面、镁液态等原子环境中的环境敏感镶嵌能，定义并计算了Mg，La及Y与氧的原子亲和能.计算结果表明：La，Y在镁晶体中的环境敏感镶嵌能较高，不能稳定固溶于晶体中，因此在固体中的溶解度较小.合金凝固时稀土元素扩散到环境能较低的液体中，向液面聚集.由于稀土与氧的原子亲和能低于镁与氧的亲和能(镁、稀土与氧的亲和能分别为Mg-O：-14.9338 eV，La-O：-19.0608 eV，Y-O：-19.5050 eV     

强化生物除磷过程中聚β羟基烷酸酯的红外光谱分析

强化生物除磷是废水生物除磷的主要技术手段。在厌氧与好氧交替运行的反应过程中,污泥中聚β羟基烷酸酯(PHA)经历了厌氧储存和好氧降解的过程,其位于1 740 cm-1吸收峰亦呈现出先增强后减弱的变化。通过比较PHA标准品的红外光谱图,实现了活性污泥PHA的红外特征归属,1 740 cm-1红外吸收峰源于PHA羰基特征吸收。利用高斯分峰法将相互重叠的PHA峰、蛋白质Ⅰ峰和蛋白质Ⅱ峰进行了分离,PHA与蛋白质Ⅰ峰的峰面积比值与PHA测定值有较好相关性,相关系数可达0.873,峰面积比值可反映污泥中PHA的变化趋势。选取1 480~1 780 cm-1区域红外光谱,经过归一化处理并转化为吸光度数据后,结合污泥样品PHA含量的色谱分析结果,应用偏最小二乘法建立了污泥样品红外光谱与PHA含量的关系模型,模型预测值与测量值具有较好的一致性,结合未知浓度活性污泥样品的红外光谱以及该关系模型,可以迅速预测未知污泥样品中的PHA含量。该方法的研究为污泥胞内PHA的快速表征和定量分析提供了新的分析方法。     

超声处理黑豆蛋白结构变化的拉曼光谱分析

探究了拉曼光谱应用于黑豆蛋白结构变化研究的可行性,研究了黑豆蛋白溶液在低频超声处理在不同超声强度、不同处理时间下的结构变化,并进行了热力学特性分析。低、中超声处理强度下TD的降低表明蛋白质分子的内部疏水作用被破坏,使黑豆蛋白不稳定的聚集体解聚为小分子可溶性聚集物,而在高超声处理强度下TD的增高表明聚集体重聚。拉曼光谱分析表明超声处理下除了E样品(300 W, 24 min)所有黑豆蛋白均发生了α-螺旋结构含量降低和β-折叠结构含量增高。聚集体的聚合/解聚导致黑豆蛋白二级结构的重组,尤其是β-折叠。超声处理使拉曼光谱在760 cm-1的色氨酸归属谱线强度降低表明超声处理使黑豆蛋白发生了部分的解折叠。超声处理下酪氨酸归属谱线强度变化不显著,表明超声处理并未显著改变黑豆蛋白酪氨酸的微环境。1 450 cm-1拉曼归属谱带随着超声处理强度和时间的增加而增大,但随着功率及处理时间的进一步增大此值有所降低。在超声处理下聚集体的形成使二硫键的g-g-t构型转变为t-g-t构型。尽管黑豆蛋白聚集体重组的机理仍有待研究,但拉曼光谱是一种研究超声处理黑豆蛋白结构变化的可行方法,也可为蛋白质结构研究提供一种新的研究思路。     

超声处理对ZnO薄膜光致发光特性的影响

对于结晶状态好的ZnO薄膜，测量了其光致发光(PL)光谱，发射光谱中只发现了峰值波长约389 nm的近紫外光.样品进行超声处理后，发射谱中不仅观察到近紫外峰，又观察到波长约508 nm的绿光峰.绿光峰的强度比近紫外光的强度强得多，且近紫外峰红移.进一步的热处理使绿光峰大大增强.超声处理改变了ZnO薄膜的质量和结晶状态，使晶格中产生氧空位.处理过程中的热效应使得薄膜晶格振动加剧.当晶格振动加剧到一定程度，晶格中的氧脱离格点形成氧空位.510 nm左右的绿色发光峰是ZnO晶体中的氧空位产生的.薄膜的温度越高， 关键词： ZnO薄膜 超声 光致发光     

超声对蛋白质盐析作用的研究

在蛋白质（牛血清白蛋白）-水胶体溶液中加入无机盐，利用蛋白质盐析的原理粗分离蛋白质是常用的生物分离技术。本文试图利用超声强化蛋白质盐析分离过程。讨论了声场参数，即频率、声强、超声辐射时间对该过程的影响。实验表明超声处理牛血清白蛋白时，20kHz超声辐照比无超声处理可缩短了近4．5小时的静置时间，20kHz超声处理可得到约90％的最高蛋白质收率；不同超声频率下有不同的最佳声压值，频率较低时的盐析效果较好；超声辐照并非时间越长越好，超声辐照2min时，牛血清白蛋白的收率最大。由此证明超声技术可加速盐析后的蛋白质沉降速度。     

Multimodal approach for diagnosis of bacterial etiology in brain abscess

Background and purpose

Proton magnetic resonance spectroscopy (PMRS) has high sensitivity and specificity for the detection of pyogenic brain abscess and the categorization of bacteria. But the metabolite patterns failed to evaluate the etiology of disease when the culture results are sterile. The aim of the present study is to compare the multimodality techniques viz., conventional culture, MR spectroscopy and 16S rRNA PCR and sequencing for rapid diagnosis of etiology in brain abscess and evaluate the PMRS in culture sterile samples and also demonstrate the sensitivity and specificity of these techniques.

Methods

Thirty five patients underwent MRI on a 3 T MRI and in-vivo PMRS for the diagnosis and evaluation of various resonances of metabolites such as lipid (LIP), lactate (LAC), acetate (AC), amino acid (AC), succinate (SUC). Pus was collected for identification of etiologic agents by culture and molecular method.

Results

In 35 samples, metabolite patterns were as follows: LIP/LAC/AA, n = 17, LIP/LAC/AA/SUC with or without AC, n = 17 and LIP/LAC/AA/AC, n = 1. Culture showed bacterial growth in 22 samples (18 aerobic/facultative anaerobic, 9 anaerobic) whereas molecular method was detected 26 aerobic/facultative anaerobic, 13 anaerobic, 4 microaerophilic bacteria. Among the 13 sterile samples, molecular method detected 16 microorganisms along with 3 mixed infections and PMRS recognized metabolite patterns as LIP/LAC/AA, n = 5 and LIP/LAC/AA/SUC with or without AC, n = 8. The sensitivity of in-vivo PMRS in sterile samples was 100% and 75%, and specificity was 75% and 100% for aerobic and anaerobic organisms respectively.

Conclusion

Based on metabolite resonances, PMRS can detect slow growing and fastidious organisms and classify them into aerobic and anaerobic bacteria which are difficult to culture by conventional method. It can categorize microorganisms even in culture sterile samples with rational sensitivity and specificity which may allow early choice of targeted therapy.     

Use of Mössbauer spectroscopy to determine the effect of salinity on the speciation of triorganotins in Anacostia River sediments

The speciation of several tributyltin and triphenyltin compounds under varying salinity conditions (0, 20, 40 and 60%) was studied by Mössbauer spectroscopy in both anaerobic and aerobic Anacostia River sediments. The Mössbauer spectral parameters of the spiked sediments indicated that changes in the salinity did not affect the speciation of the tin compounds in either aerobic or anaerobic sediments.     

Particle size and gas environment effects on blast and overpressure enhancement in aluminized explosives

Aluminized RDX-based explosives were detonated under controlled conditions while varying particle size and atmosphere in an effort to quantify the contribution of aerobic and anaerobic Al reaction to blast and overpressure. Early time reaction of aluminum acts to enhance the primary explosive blast, and this reaction is approximately half aerobic and half anaerobic (i.e. oxidation by detonation products and/or nitridation), suggesting that very rapid early-time mixing occurs in explosive fireballs. Particle size effects are surprisingly negligible over the range of 3–40 μm, which implies that conventional scaling laws for aluminum combustion provide less insight than previously assumed. Quasi-static pressures obtained in the time period from 5 to 10 microns after detonation suggest that oxidation of aluminum is complete in the presence of 20% oxygen. However, for nitrogen environments, oxidation only proceeds to half its theoretical maximum, except for the smallest (3 μm particles) for which oxidation was nearly complete. These results demonstrate that oxidation of aluminum in aluminized explosives is robust in anaerobic environments, and that simulation efforts cannot neglect anaerobic channels, even though aerobic oxidation provides the greatest energy release.     

Diffusion of 99-technetium in compacted bentonite under aerobic and anaerobic conditions

The main aim of this study was to investigate diffusion of technetium ⁹⁹Tc under different conditions. Because technetium represents one of the most dangerous fission products due to its very long halftime and high mobility in aerobic conditions diffusion experiments of technetium (as ⁹⁹TcO ₄ ⁻ anion) in Czech bentonite from Rokle locality have been carried out. For performance and evaluation of experiments the through-diffusion method was chosen and apparent (D_a) and effective (D_e) diffusion coefficients were evaluated. The effects of particle mesh-size, dry bulk density and aerobic or anaerobic conditions on diffusion were studied. In the presence of oxygen, technetium occurs in oxidation state VII, as an anion, soluble and mobile in the environment. However, under reducing conditions it occurs in a lower oxidation states, mainly as insoluble oxides or hydroxides. Aerobic experiments were carried out under laboratory conditions and anaerobic experiments were performed in a nitrogen atmosphere in a glove box, to simulate the real underground conditions.     

Bioenhancement of Soil Microorganisms in Natural Surfactant Solutions: II - Anaerobic

Natural surfactant solutions obtained from fruit pericarps of Sapindus mukorossi are shown to solubilize significant quantities of hydrophobic organic compounds and mobilize them from soil matrix. It is very crucial to determine the fate of surfactants employed for soil flushing in the subsurface and also in the effluent recovered. This paper appraises the bioenhancement of soil microorganisms in natural surfactant solutions under anaerobic conditions. Sealed 125 ml serum bottles are used for developing the anaerobic cultures. The cultures are maintained in anoxic conditions by degassing and filling the bottles with nitrogen. Three concentrations of natural surfactant 0.1, 1 and 2% and two different nutrient media, basal salt media (BSM) and heterotrophic media are used in the studies. Natural surfactant solutions can serve as both carbon and energy source for anaerobic microorganisms and also degrade to considerable extent. The growth curves for anaerobic cultures followed similar trends as those for aerobic cultures reported in an earlier paper. Addition of BSM to cultures increased the growth significantly. However, heterotrophic media amended cultures showed only an increased initial growth rate. The microbial growth increased significantly when the surfactant concentration was increased from 0.1 to 2% by weight. The results suggest that natural surfactant can readily degrade under anaerobic conditions and needs to be studied further in the presence of soils and sediments.

     

Investigations of succinate dehydrogenase and fumarate reductase in whole cells ofShewanella putrefaciens (strains MR-1 and MR-7) using electron spin resonance spectroscopy

Using ESR spectroscopy we were able to detect succinate dehydrogenase (SDH) in the whole cells ofShewanella putrefaciens grown aerobically. ESR analysis of cells grown under anaerobic conditions in the presence of fumarate as electron acceptor revealed signals with the same parameters as SDH. However the temperature dependence was quite different. Furthermore, the addition of sodium azide led to disappearance of this ESR signal in anaerobic cultures, while the same treatment of aerobic cultures had no effect on the ESR signal of SDH. Based on these results, we postulate that the ESR signal from the anaerobic cells is that of fumarate reductase, similar in its properties to the fumarate reductase fromEscherichia coli.     

Thermodynamic optimality in some biochemical reactions

Summary In this short communication we discuss the possibility that anaerobic glycolisis and (aerobic) respiration, both for adenosine triphosphate (ATP) production, be chemical reactions that follow different thermodynamic-optimization criteria. The former reaction maximizing power output and the latter maximizing a function that represents an advantageous compromise between high power output and low entropy production. Our approach is by means of finite-time thermodynamics (FTT).     

Ecofriendly Route for the Synthesis of Highly Conductive Graphene Using Extremophiles for Green Electronics and Bioscience

Highly conductive biocompatible graphene is synthesized using ecofriendly reduction of graphene oxide (GO). Two strains of non‐pathogenic extremophilic bacteria are used for reducing GO under both aerobic and anaerobic conditions. Degree of reduction and quality of bacterially reduced graphene oxide (BRGO) are monitored using UV–vis spectroscopy, X‐ray photoelectron spectroscopy, and Raman spectroscopy. Structural morphology and variation in thickness are characterized using electron microscopy and atomic force microscopy, respectively. Electrical measurements by three‐probe method reveal that the conductivity has increased by 10⁴–10⁵ fold from GO to BRGO. Biocompatibility assay using mouse fibroblast cell line shows that BRGO is non‐cytotoxic and has a tendency to support as well as enhance the cell growth under laboratory conditions. Hereby, a cost effective, non‐toxic bulk reduction of GO to biocompatible graphene for green electronics and bioscience application is achieved using halophilic extremophiles for the first time.