The influence of coal ash and thermal discharges upon the distribution and bioaccumulation of aquatic invertebrates

The distribution, density and uptake of twenty elements by aquatic invertebrates inhabiting a drainage system, that received excessive coal ash effluent (275 JTU of turbidity) at one end and thermal loading (44.5°C) at the other end, was studied for 15 months. The ash settling basin filled during the first eight months of sampling which resulted in the release of ash effluent directly into the receiving system. Density of invertebrates was lowest in the 300 m stream between the ash basin and swamp and highest 1200 m beyond the stream-swamp confluence where ash influence was minimal. Invertebrate density was lowest in the stations where turbidity from ash effluent was greatest. The most tolerant invertebrates to coal ash stress were odonates (Libellula sp. and Enallagma sp.), crayfish (Procambarus sp.), amphipods (Gammarus sp.) and gastropods (Physa. sp.), and midges (Chironomidae) when the basin was filling. During the period of ash overflow, all groups were either reduced in numbers or absent. In the thermally stressed station, Libellula sp. was the predominant invertebrate sampled when water temperature ranged from 25.5–45.5°C (257-1=28.7°C) all aquatic invertebrates were limited in numbers and density when temperature exceeded the lower and upper ranges of 10.0–38.0°C.This research was supported by AEC Contract AT (38-1-824)This research was supported by AEC Contract AT (38-1-824)     

The hydration of phospholipids and phospholipid-cholesterol complexes

The hydration characteristics of phosphatidylcholines and the effect of cholesterol on these were studied with differential thermal analysis and water vapour adsorption experiments. Also the water adsorption of egg phosphatidylethanolamine and the effect of cholesterol on this was studied and compared with corresponding qualities of phosphatidylcholine.The differential thermal analysis study showed that the monohydrates of egg, dipalmitoyl, and dioleoyl phosphatidylcholine tightly bind ～9 molecules of water per phosphatidylcholine molecule. Cholesterol is proved to somewhat increase the water binding of the phospholipids. Cholesterol is also shown to decrease the heat change of the chain melting transition of dioleoyl phosphatidylcholine, but not to abolish it completely.The water adsorption experiments indicate that the hydration of phosphatidylcholines takes place in two steps; a strong initial water binding and a second phase of weak binding. The adsorption isotherm of egg phosphatidylethanolamine is strikingly different from that of egg phosphatidylcholine. Cholesterol is shown, also by this method, to increase the hydration of phospholipids especially that of dipalmitoylphosphatidylcholine.The results in this study are in good agreement with those presented by many other authors. Starting with the accumulated information of the hydration characteristics of phosphatidylcholines the organization of the bound water around the polar group is discussed and the most probable model is evaluated.     

Effects of ELF magnetic fields on biological magnetite

The effects of 60 Hz magnetic fields of 5 μT (50 mG) or less on biological structures holding magnetite (Fe₃O₄) are shown to be much smaller than that from thermal agitation; hence such interactions cannot be expected to be biologically significant. © 1993 Wiley-Liss, Inc.     

Patterns of variation in desiccation resistance in a set of recombinant inbred lines in Drosophila melanogaster

Desiccation, resulting from extremely dry environmental conditions, is a serious obstacle to the survival of organisms. Water is vital for the maintenance of intracellular structure and prevents the irreversible formation of aggregates, an occurrence leading to loss of cellular function. To characterize genetic variation in desiccation stress resistance (DSR) in Drosophila melanogaster Meigen, an intercontinental set of recombinant inbred lines (RIL) is used. Flies are exposed to a low humidity environment (<10% relative humidity) at a constant temperature of 25 °C. Desiccation stress resistance is higher in RIL derived from a backcross to the parental stock sensitive to heat stress (from Denmark) than in RIL derived from the reciprocal backcross to the heat‐stress resistant stock (from Australia). Composite interval mapping reveals significant quantitative trail loci (QTL) for DSR in the set of RIL. Both major and minor effects QTL are detected, suggesting a complex genetic architecture. When compared with a previous investigation performed on the same set of RIL, the present study indicates that not all traits of resistance to environmental stressors are affected in the same direction by segregating co‐localized QTL.     

Spectral imaging for precise surgical intervention in Hirschsprung's Disease

We used advanced spectral imaging for intrasurgical decision making in a preclinical study, on a mouse model of Hirschsprung's Disease. Our imaging device sampled areas from normal and abnormal (aganglionic) colon in these animals. Spectral segmentation and classification of the resulting images showed a clear distinction between the normal and aganglionic regions, as confirmed by pathological analysis and use of mutant mice. We developed a simple algorithm that could distinguish normal from aganglionic colon with high spatial resolution and reproducibility, and the following statistics: sensitivity = 97%, specificity = 94%, positive predictive value = 92%, negative predictive value = 98%. These studies showed translational proof of concept that spectral imaging could be used during operations, in real time, to help surgeons precisely distinguish normal from abnormal tissue without requiring traditional biopsy. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The role of causal knowledge in the evolution of traditional technology

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A novel aggregation-induced emission fluorescent probe for nucleic acid detection and its applications in cell imaging

A new kind of aggregation-induced emission compound was synthesized and used as the probe of nucleic acid. The characterization of this compound was studied. Both the RNA and DNA were detected by using this probe. And the detection scope of DNA and RNA was different. We researched the selectivity of our probe in double and single strand DNA sequences. The visualization of gel electrophoresis and the cell nucleus imaging were researched as well. Compared with the traditional nucleus dye Hoechst 33258, our probe also has the potential to be nucleus dye. And the cell toxicity was well performed by MTT assays.     

纳米孔测序技术在病毒性传染病检测及研究中的应用

快速、准确鉴定出病原体是临床感染性疾病诊断和传染病预防控制的基础。高通量测序基因检测技术突破了传统检测手段的时效性、灵敏度等的局限，为病原体检测和研究提供了便捷、高效的途径。本综述以高通量测序技术发展过程为基础，回顾纳米孔三代测序技术，及其在病毒性传染病检测鉴定及研究中的应用，并对该技术的应用前景及可能存在的问题进行阐述，期望它能在病毒性传染病的防控方面发挥更大的作用。     

An automated differential thermal and potentiometric titration apparatus for binding studies

A differential pH-termal titration apparatus is described which can detect pH differences with a sensitivity of ±0.0001 pH units and a thermal sensitivity of ±0.00002°C at a time constant of 0.1 s. With a reaction which yields 1 kcal mol⁻¹, the current system can detect concentrations as low as 4×10⁻⁶ M or, in a 2 ml volume, a total amount of 40 nmol. With a time constant of 0.1 s, the sensitivity is 20±4 μ°C. The experimental protocol is specified by a microprocessor and three modes of operation are possible: titration at constant rate of reagent addition, titration at variable rates of addition so that the contents of both cells are at either constant pH or at a constant temperature and variable rate when a rate of change is specified. Experimental data are collected in files, corrected for heat loss, initial baseline drift, and changes in volume. The final corrected from the standardized run of 0.01338 M HCl in 0.2 M KCl at 25°C calibrate the pH scale yielded the calorimetric conversion constants and pK_w which are calculated and stored for subsequent corrections for the titration of an unknown acid or the measurement of bindin constants and heats.