Stability of 5,5-dimethyl-1-pyrroline-N-oxide as a spin-trap for quantification of hydroxyl radicals in processes based on Fenton reaction.

Fenton reaction was used to produce hydroxyl radicals under conditions similar to AOPs with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trap agent in electron paramagnetic resonance (EPR) analysis. A theoretical kinetics model was developed to determine conditions under which the spin-adduct DMPO-OH is not further oxidized by Fe(3+) and excessive radicals, so that hydroxyl radicals concentration could be accurately inferred. Experiments were designed based upon the model and H2O2 and Fe(2+) concentrations were varied from 1 to 100 mM and from 0.1 to 10 mM, respectively, with a constant H2O2: Fe(2+) ratio of 10:1. Results confirmed that DMPO concentration should be at least 20 times higher than the concentration of H2O2 and 200 times higher than iron concentration to produce stable DMPO-OH EPR signal. When DMPO: H2O2 ratio varied from 1 to 10, DMPO-OH could generate intermediates and be further oxidized leading to the apparition of an additional triplet. This signal was attributed to a paramagnetic dimer: its structure and a formation mechanism were proposed. Finally, the utilization of sodium sulfite and catalase to terminate Fenton reaction was discussed. Catalase appeared to be compatible with DMPO. However, sodium sulfite should be avoided since it reacted with DMPO-OH to form DMPO-SO3.

Serial analysis of gene expression in adenocarcinoma samples and normal colonic mucosa in a Chinese population.

The goal of this study was to identify the differences in gene expression between adenocarcinoma samples and colonic normal mucosa of a Chinese population. Gene expression libraries of adenocarcinoma and normal colonic mucosa were generated by serial analysis of gene expression (SAGE). Expression tags were obtained from sequencing results using the SAGE2000 software. Representative genes of tags were determined based on the SAGEmap from NCBI. Expressed genes were selected and their expression in different libraries was compared using the SPSS 17.0 software. The expression of 78 tags representing 88 types of genes showed significant differences. Compared with normal mucosa, 38 genes showed decreased expression in cancer, whereas the expression of the remaining 50 genes showed significant up-regulation. Expressed tags in SAGE libraries of normal and cancerous tissues were significantly different. Further studies examining these genes, which showed different expression levels between the 2 tissues, may be used as tumor markers and offer clues for studying the etiopathogenesis of colon cancer.

Bioactivity-guided fractionation for analgesic properties and constituents of Vitex negundo L. seeds.

This study was undertaken to ascertain the analgesic properties of Vitex negundo L. seeds and to isolate and characterize the active constituents. Among the 80% ethanol extract and some fractions with different polarity, the acetoacetate fraction showed the highest anti-nociceptive activity in acetic acid-induced writhing test in ICR mice. The analgesic bioguided isolation of the acetoacetate fraction yielded two major lignans: 6-hydroxy-4-(4-hydroxy-3-methoxy-phenyl)-3-hydroxymethyl-7-methoxy-3,4-dihydro-2-naphthaldehyde (1) and vitedoamine A (2). Given orally, compound (1), which was more productive, produced significant inhibitions on chemical nociception induced by intraperitoneal acetic acid and subplantar formalin injections and exhibited notable anti-inflammatory activities in dimethyl benzene-induced ear edema test in a dose-dependent manner. Since co-administration of naloxone fails to antagonize the analgesic activity of compound (1) in the formalin test, we suggest that compound (1) possesses potent analgesic effects which are most likely to be mediated by its anti-inflammatory activity rather than through opioid receptor system and therefore could partially explain the anti-nociceptive effect of V. negundo L. seeds.

Screening of a fungus capable of powerful and selective delignification on wheat straw.

AIMS: To screen and characterize a novel fungus with powerful and selective delignification capability on wheat straw. METHODS AND RESULTS: A fungus capable of efficient delignification under solid-state fermentation (SSF) conditions on wheat straw was screened. After 5 days of incubation, 13.07% of the lignin was removed by fungal degradation, and 7.62% of the holocellulose was lost. Furthermore, 46.53% of the alkali lignin was removed after 2 days of liquid fermentation. The fungus was identified as Fusarium concolor based on its morphology and an analysis of its 18S rDNA gene sequence. The molecular weight distribution of lignin was evaluated by gel permeation chromatography. Enzyme assay indicated that the fungus produced laccase, cellobiose dehydrogenase, xylanase and cellulase during the incubation period. Intracellular lignin peroxidase, manganese peroxidase and laccase were produced during liquid fermentation. CONCLUSIONS: We have successfully screened a fungus, F. concolor, which can efficiently degrade the lignin of wheat straw, with slight damage to the cellulose, after 5 days of SSF. SIGNIFICANCE AND IMPACT OF THE STUDY: The newly isolated strain could be used in pretreatment of lignocellulose materials prior to biopulping, bioconversion into fuel and substrates for the chemical industry.

INT-dehydrogenase activity test for assessing anaerobic biodegradability of organic compounds.

This study assessed anaerobic biodegradability of organic compounds from microorganism activity. Dehydrogenase activity can be a good parameter characterizing the microorganism activity. A modified method of 2-(p-iodophenyl-3-(p-nitrophenyl)-5-pheny tetrazolium chloride-dehydrogenase activity determination was proposed in anaerobic biodegradability assessment. Cubic spline curves were adopted to link the data points. This curve was integrated twice to calculate areas. The microorganism activity index in anaerobic biodegradability assessment was calculated by standardizing the integral. According to the results of the activity index, 14 kinds of organic compounds were classified into readily, partially, and poorly biodegradable under anaerobic conditions, respectively. As a result, some conclusions for anaerobic biodegradability of organic compounds were reached, based on the activity index value.

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.

[Studies on the establishment of malarial animal model of short-term relapse. IV. Short-term relapse in rhesus monkeys infected with sporozoites of Plasmodium cynomolgi].

The present paper reports that the short-term relapse could be artificially made by the application of the experimental method, and thus we established the monkey model of the short-term relapse. According to the experimental design, when the parasitemia was detected in rhesus monkeys infected with sporozoites of Plasmodium cynomolgi, a combined therapy of pyronaridine 6 mg/kg body weight, artemether 10 mg/kg and chloroquine 20 mg/kg once daily for 3 days was carried out to clear the erythrocytic parasite and then the short-term relapse was observed in the animal follow-up for 100 days. The combined therapy was given again when relapse occurred. One onset of relapse occurred on 47 days after therapy in monkey M194 infected with sporozoites 11 x 10(3). In M195 infected with sporozoites 55 x 10(4), relapses occurred for 3 times on 30, 37 and 51 days respectively after medication, but during a follow-up period of 200 days, no relapse was shown in M192 and M193 infected with sporozoites 50 and 55 x 10(2), respectively. The results showed that the frequency of the short-term relapse was relative to the sporozoites inoculation, and sporozoites less than 11 x 10(3) were not suitable for making short-term relapse in animal model. No long term relapse could be seen in all the 4 monkeys until 400 days. Under existing conditions that the relapse was generally explained with hypnozoite assumption, the establishment of animal model of short-term relapse could be tenable.(ABSTRACT TRUNCATED AT 250 WORDS)

[Studies on the establishment of malarial animal model of short-term relapse. I. Asynchronous growth of exoerythrocytic schizonts of Plasmodium cynomolgi].

A monkey was infected with sporozoites of Plasmodium cynomolgi from Vietnam. Parasitemia was detected on the 8th day with a starting density of 17/100 white blood cells. 22 hours after that time, many EE schizonts appeared with an average density of 3.74 +/- 0.66 per mm3 hepatic tissue in liver biopsy specimens from the monkey. Most of the EE schizonts were immature and grew at an uneven rate, having an average diameter of 34.22 +/- 7.28 microns but some of them even remained 15.75 +/- 2.47 microns in diameter similar to the EE schizonts on the 6th day. The results showed that the EE schizonts of Plasmodium cynomologi were asynchronous in growth. The authors suggest that the release of merozoites from liver might be a successive process for many times, and not to be completed at a time.

Sex and age difference in adolescents' value judgements of historically important events: theory, stereotypes and data.

The extent to which younger and older adolescents differed in their value judgments of historically important events was examined. Subjects were asked to list the ten most important events that happened in or to the U.S. since 1990. The subjects' choices were analyzed as a function of sex, age, political and religious orientation, and family size. In addition, 100 undergraduates were asked to serve as judges and predict which categories would be cited more frequently by males and which by females. Results indicated that the judges' predictions did not match the data. Age was a much better predictor of value judgments than sex. Further, several additional differences in value judgments were revealed that would have been missed had only the variables of sex and age been included in the analyses.

Teaching chronic psychiatric inpatients to use differential attention to change each other's behaviors.

For nine months, all psychiatric inpatients who came into a 26-bed coed adult ward in a state hospital were taught the principles and application of differential attention to determine whether it could be a used as a significant therapeutic modality on a ward for chronic patients. In two half-hour classes each week, patients were encouraged to praise each other's desirable behaviors and ignore undesirable ones. Thirteen patients were measured for improvement of 21 behaviors that included self-care, adaptive, and social skills. The target behaviors doubled in frequency as a result of the intervention, and praise improved the performance of target behaviors whether the praise was prompted by staff or not. Men and women improved equally from the intervention. Behaviors that were consistently prompted by patients improved more than self-initiated behaviors. Patients who volunteered to be helped by peer praise appeared to benefit the most.

The crystallographic study of the complex of the Lys active fragment of the mung bean trypsin inhibitor with bovine trypsin.

The Lys fragment of mung bean trypsin inhibitor can combine with bovine trypsin to form a complex at an equal molar ratio. The single crystals of the complex were obtained by using the micro-still-setting method and the X-ray diffraction extended to 1.8A resolution. Its space group is P212121 with cell dimensions a = 62.9(1)A, b = 63.4(1)A and c = 69.7 (2)A. There is one complex molecule in a crystallographic asymmetric unit.