Minimum amount of extracting solvent of AB/BC countercurrent extraction separation using organic feed

For an AB/BC countercurrent extraction separation using organic feed, the conditions to have minimum amount of ex- tracting solvent （Smin） and minimum amount of scrubbing agent solution （Wmin） were discussed, and the formulae of both Sroin and Wmin were deduced. It was shown that only when the ratio of flowrate of central component B leaving aqueous outlet to that leaving organic outlet took a certain optimal value, the AB/BC separation could have Smin as well as Wmin, and this optimal ratio was decided by the separation factors between the three components but independent of feed composition. Smin was only relative to the separation factor of A/C pair but regardless of the separation factors of other pairs as well as feed composition, whereas Wmin was determined by the separation factors between the components together with feed composition. Meanwhile it was also found that the organic stream out of feed stage was same composition as the initial organic feed when the separation system was given by the two minimum amounts and its steady state was achieved. Finally the results above were used to design a LuYb/YbTm separation case and the stage-wise compositions of each component in both the organic and the aqueous phase at steady state were given by computer simulation.     

Evidence of multiple extracellular phospholipase activities of Aspergillus fumigatus

Extracellular phospholipase activity has been implicated in the pathogenesis of several bacterial infections. Recently, extracellular phospholipase activity has been proposed as a virulence factor in the opportunistic yeast Candida albicans. Aspergillus fumigatus is the most pathogenic member of its genus, responsible for > 90% of infections. Previously, no specific virulence factors have been determined. We investigated the ability of A. fumigatus to produce extracellular phospholipases at 37 degrees C. Fast atom bombardment was used to compare lipid-containing media before and at 5-h intervals during shaking culture of A. fumigatus. Lipids were extracted and analyzed. Many anions corresponding to phospholipid breakdown products were identified. Specific anion species identified indicated phospholipase A, B, C (PLC), and D activities. PLC activity was further investigated by using the synthetic substrate p-nitrophenylphosphorylcholine. PLC activity was initially observed after 30 h of growth and accumulated in broth cultures up to 50 h. At 55 h, there was a sharp increase in PLC activity which coincided with cultures reaching the stationary phase. Activity of the PLC was measured at different temperatures, with greater activity occurring at 37 degrees C than at lower temperatures. Phospholipases could represent a virulence determinant in A. fumigatus.     

Lipase-catalyzed synthesis of arbutin cinnamate in an organic solvent and application of transesterification to stabilize plant pigments

Arbutin cinnamate was synthesized from arbutin (4-hydroxyphenyl beta-D-glucopyranoside) and vinyl cinnamate by regioselective transesterification with a bacterial lipase in acetonitrile. The product was identified by NMR and FAB-MS analyses. These spectra showed that one ester bond was formed between the primary alcohol moiety of the D-glucose of arbutin and the carboxyl residue of cinnamic acid. Furthermore, plant pigments such as isoquercitrin (quercetin 3-O-beta-D-glucopyranoside) and callistephin (pelargonidin 3-O-beta-D-glucopyranoside) were also converted to their corresponding cinnamate esters in the same manner.     

A case-control study of fatty liver disease and organic solvent exposure

BACKGROUND: Clinical experience of cases of fatty liver disease (FLD) with exposure to organic solvents suggested a possible risk. METHODS: Thirty male cases of FLD, ages 20-59 years, with biopsy records at departments of pathology in southeast Sweden were compared to 120 male controls randomly drawn from the study area population. Questionnaire information was obtained about job titles and specific occupational exposures; exposure level categories were then assessed blindly for both cases and controls. Medical records for cases were scrutinized to elucidate possible confounding and/or interacting effects from alcohol, the use of drugs, and other diseases. RESULTS: Moderately intense and mixed solvent exposure for more than 1 year within the last 15 years prior to diagnosis resulted in an age-adjusted Mantel-Haenszel odds ratio of 4.3 (95% confidence interval (CI), 1.2-15); for intense exposure, the odds ratio was 7.7 (95% CI 1.7-48). Confounding from alcohol, use of drugs, other diseases, and overweight could be ruled out with reasonable confidence. CONCLUSIONS: This study indicates that occupational exposure to organic solvents may play a role in the development of FLD, as indicated earlier in case reports and in one small case-control study.     

PCR product quantification by non-radioactive hybridization procedures using an oligonucleotide covalently bound to microwells

Oligonucleotides derived from IS6110, an insertion sequence from Mycobacterium tuberculosis, have been covalently immobilized on polystyrene Covalink NH microwells to develop a sandwich and a competitive non-radioactive hybridization assay for the quantitative determination of the DNA fragments obtained by polymerase chain reaction (PCR). Using the appropriate standard DNA, the method can be employed for the quantitative analysis of PCR fragments. The sandwich assay can detect as little as 3 fmol of target DNA per well and the standard curve may be used with quantities ranging from 3 to 300 fmol per well. The competitive hybridization assay is less sensitive since it is quantitative between 100 and 8000 fmol per well. We show here that both kinds of assays can be used to identify M. tuberculosis strains isolated from clinical samples. The non-radioactive hybridization procedures using an oligonucleotide covalently bound to microwells involve few and simple operations, and are thus suitable for routine diagnosis. Moreover, when stored at 5 degrees C, precoated strips can still be used for hybridization up to at least 10 months.     

Interactive intraoperative localization using an infrared-based system

We discuss new methods of localizing and treating brain lesions for both the conventional method of a base-ring fixed to the patient's skull (referred to as frame-based procedures) and the new method of frameless procedures (no base ring). Frame-based procedures are used for finding a precise instrument position during neurosurgical procedures, such as stereotactic biopsy of deep-seated lesions, placing electrodes for functional stereotaxis or catheters with radioactive seeds for brachytherapy, or even the placement of a stereotactic retractor or endoscope for removal or internal decompression of lesions. In such procedures, the intraoperative image localization of instruments becomes useful as it tracks instruments as they travel through the preplanned trajectory. Additional intraoperative digitization of surgical instruments, e.g., bipolar suction, biopsy forceps, microscope, ultrasound probe, etc, can be achieved during the stereotactic resection of eloquent areas or deep intracranial lesions by adding an infrared-based system. Frameless procedures broaden the range of surgical approaches, image guidance planning, and operative procedures, since no ring is attached to the patient's head which might interfere with the surgical approach, and offers logistic advantages in scheduling diagnostic studies. Frameless diagnostic studies employ anatomical markers and/or surface matching techniques for data registration in the computer software surgical preplanning program. This simplifies scheduling of the procedures since the image study does not need to be acquired the same day as surgery. Frameless diagnostic studies allow for the use of more than one type of imaging data for planning and optimization of surgical procedures, and greatly improve patient tolerance and comfort during these procedures and during surgery, as compared with frame-based procedures.(ABSTRACT TRUNCATED AT 250 WORDS)     

The measurement of hydrogen activities in molten copper using an oxide protonic conductor

We have developed a hydrogen sensor for in situ measurements of hydrogen activities in molten copper. The sensor consists of a concentration cell utilizing a proton conductor, CaZr_0.9In_0.1O_3-δ, as the solid electrolyte. The electromotive force (emf) of the cell was generated by both hydrogen and oxygen activity gradients across the cell in a high-temperature region simulating the fire refining processes of copper. However, accurate hydrogen activity in molten copper could be evaluated from the emf if oxygen activity in molten copper was determined simultaneously by another concentration cell and if the hydrogen and the oxygen activities at the reference electrode were known. The performance of the sensor was studied under various conditions. The observed good response and reliability of the sensor show that it should be a powerful tool for improvement of the fire refining process of the molten copper. Theoretical treatment of the calculation of the emf of the concentration cells using a mixed ionic conductor, i.e., protonic and oxide ionic conductor, as solid electrolytes is also discussed briefly.     

Immunotropic activities of benzisoselenazolones and organic diselenides in mice

We have investigated the immunotropic effects of 23 seleno-organic compounds (8 benzisoselenazolones, 3 benzisoselenazolone oxides and 12 organic diselenides). All of the compounds increased the rosette formation of sheep red blood cells (SRBC) with spleen cells obtained from thymectomized C53BL/6 mice and incubated in vitro in the presence of imuran. Furthermore, 16 of the compounds were also assayed in vitro in the hydrocortisone test performed with C57BL/6 mouse thymocytes. It was found that all of them significantly protected the cells against hydrocortisone induced cytotoxicity. Also in the Jerne's assay, performed in 129Ao/Boy mice pretreated in vivo with 3 selected compounds 5 days before immunization with SRBC, the stimulation of plaque forming cells (PFC) was observed. Only one compound (AE22, an analog of piroxicam) was found to be inhibitory in this assay. In contrast, in the graft versus host (GvH) assay performed in hybrid mice the donor lymphoid cells obtained from C57BL/6 mice pretreated with 9 selected seleno-organic compounds, suppressed the GvH reaction in the recipient hybrid mice. Thus, in all of the immunotropic assays except the GvH reaction in adult mice, the seleno-organic compounds were found to have immunostimulating activities.     

Microbial recovery of uranium using native fungal strains

Native microorganisms were isolated from water samples collected from uranium mines of Jaduguda, Bhatin and Nawapahar of UCIL India. Ten fungal strains isolated in pure cultures were selected, identified and used in this study. The strains were used for in situ leaching of mainly oxide low grade uranium ore of Turamdih mine. The maximum recovery of 71% uranium was obtained with the strain Cladosporium oxysporum. The other two strains belonging to Aspergillus flavus and Curvularia clavata gave 59% and 50% of metal recovery respectively from the same ore.     

新型有机黏结剂HC用于制备冷压球团的研究

采用新型有机黏结剂(HC)代替膨润土制备冷压球团的方法,得到高冶金性能的入炉原料.随着HC和膨润土用量(质量分数,下同)的增加,铁矿球团和含碳球团生球的抗压强度均呈逐渐升高的趋势,当黏结剂用量为1.5％时,抗压强度分别为5264,2012 N/个;生球落下强度随着HC用量的增加而增加,但随着膨润土用量的增加变化趋势不明...     

Thermodynamics of the Cr-Mn system using an isopiestic technique

Activities of manganese in solid chromium-manganese alloys have been determined at 1223, 1273, and 1323 K using an isopiestic technique. The activities of manganese show positive deviations from Raoult’s law over chromium-rich compositions. The positive deviation of the system is found to decrease progressively with increase in the manganese content of the alloys. The data have been interpreted based on calculation involving solid-liquid equilibria in the system.     

Thermodynamics of the Cr-Mn system using an isopiestic technique

Activities of manganese in solid chromium-manganese alloys have been determined at 1223, 1273, and 1323 K using an isopiestic technique. The activities of manganese show positive deviations from Raoult’s law over chromium-rich compositions. The positive deviation of the system is found to decrease progressively with increase in the manganese content of the alloys. The data have been interpreted based on calculation involving solid-liquid equilibria in the system.     

Biological treatment of dye wastewaters using an anaerobic-oxic system

Three dye solutions, namely, C.I. Acid Yellow 17, C.I. Basic Blue 3, and C.I. Basic Red 2, were treated in an upflow anaerobic sludge blanket (UASB) reactor followed by a semi-continuous aerobic activated sludge tank. When hydraulic retention time was about 12 hours, no significant color removal was observed in the aerobic stage. In the anaerobic stage, Acid Yellow 17, Basic Blue 3, and Basic Red 2 were removed by 20%, 72%, and 78%, respectively. To treat wastewater from a dye manufacturing factor with COD concentration of 1200 mg/l and Color of 500 degrees (dilution factor), an UASB reactor (4.5 liters) and an activated sludge tank (5 liters, adjustable), COD and color were removed by more than 83% and 90% at a COD loading rate of 5.3 kg COD/m3-day in the anaerobic stage, and at the hydraulic retention time of 6-10 hours for the anaerobic stage and 6.5 for the aerobic stage. The anaerobic stage of the A/O system removes both color and COD. In addition, it also improves biodegradability of dyes for further aeroic treatment.     

酸性体系中钼的溶剂萃取研究进展

目前酸浸工艺已广泛应用于各种含钼物料的处理,而由含钼酸浸溶液中萃取分离钼已愈来愈受到关注.文中在综述酸类萃取剂、中性萃取剂、胺类萃取剂从酸浸液中萃取分离钼工艺研究现状的基础上,对各类萃取剂萃钼机理及优缺点进行了分析,并指出了进一步研究的方向.      

Dynamic modelling of an industrial copper solvent extraction process

The dynamic behaviour of an industrial copper solvent extraction mixer–settler cascade is modelled to develop an advanced process control system. First, the process is introduced and the dynamical models are formulated. The testing environment is described and the successful results presented. Only industrially measured variables are required and plant-specific McCabe-Thiele diagrams are utilized to predict copper concentrations. The results with constant and adapted parameters are compared and the importance of parameter adaptation is discussed. Testing the simulator with adapted parameters over a period of 1 month of industrial operating data gave data that followed the real process measurements closely. In the future, the mechanistic models will be used for control system development and testing. The model can be used on all copper solvent extraction plants by modifying the flow configuration and adapting parameters.     

Calculating activities from the phase diagram involving an intermediate compound using its entropy of formation

A new method for calculating activities of components from phase diagrams involving several intermediate compounds has been presented, in which only the entropies of formation of the intermediate compounds are required. It is expected that this method will be useful in situations where the free energy of formation, partial molar enthalpy and other thermodynamic data are not available. The application of this procedure to the Au−Bi and Mg−Si systems demonstrates that this method is feasible. Finally, activity values for the Au−Sb system are calculated by this method. JIAN-JUN WANG, former Student in the Department of Physical Chemistry, Beijing University of Iron and Steel Technology, Beijing, People's Republic of China.     

Separation of middle rare earths by solvent extraction using 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester as an extractant

The extraction of the trivalent middle rare earths from chloride media by kerosene solutions of 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester as an extractant was studied. The separation factors between the elements using solution simulating wastes from NiMH spent batteries have been evaluated: the order of the extractive ability of extractant can be confirmed in ThGdEuSm.     

Development of guidelines to designate alleles using an STR multiplex system

A random sample of 876 subjects aged 65-79 years were investigated by means of a questionnaire concerning sleep and related factors. Sleep problems were reported by 23.8% of females and 13.3% of males. Moderate or major complaints of maintaining sleep were reported by 43.5% of subjects, early morning awakening 33.4% and difficulties falling asleep 31.4%. Daytime sleepiness was more common among males, and a relationship between daytime sleepiness and perceived poor sleep was found. Daytime napping was common, but not related to poor sleep. The prevalence of regular sleeping pill users was 7.6% for females and 3.0% for males and a relationship between sleep problems, sleeping pill usage and psychiatric symptoms was established. Among the regular sleeping pill users 39.1% had possible depression (PD) and 63.0% had possible anxiety disorder (PA). Among respondents with sleep complaints 29.8% had PD and 48.7% had PA. Sleep problems were also related to impaired physical health. Various medical illnesses contributed to sleep complaints among males, and depression affected sleep the most among females.