ABSTRACT
The School of Basic Medical Sciences of North Sichuan Medical University explores the reform of the basic medicine teacher's ability cultivation from the following aspects, including the classroom teaching quality, practical teaching skills, the innovation ability of scientific research, the basic and clinical integration and so on. Practice has proved that these reforms have greatly improved the quality of teachers' abilities and also the quality of education and teaching.
ABSTRACT
Bismuth oxide bromide, BiOBr, was used to catalyze the degradation of microcystin-LR (MC-LR) in water at neutral pH under visible light. During the investigation, twelve intermediates from MC-LR decomposition were identified by LC-MS. In addition to attacking MC-LR at the typically susceptible sites (i.e., the conjugated double bond of the Adda chain and terminal unsaturated bond of the Mdha chain), the BiOBr photocatalyst has the remarkable ability to decarboxylate the free acid groups on d-glutamic acid (Glu) and methyl-d-aspartic acid (MeAsp). This reactivity has not been previously observed with TiO2 photocatalysis or with other MC-LR treatments in which decarboxylation does not occur until the MC-LR ring has been cleaved or mineralized to CO2. Some expected intermediate products were detected with oxygen-18 labeling by using H2(18)O as the solvent to confirm that the decarboxylation process is mediated by BiOBr. Results from characterizing the intermediates as well as oxygen-18 labeling studies indicates that oxidative decarboxylation of MC-LR by BiOBr photocatalysis is not always initiated by hydroxyl radical attack (and/or interaction with a hole followed by hydrolysis) proposed mechanism in TiO2 photocatalysis, whereas likely caused by a direct interaction between photoinduced hole of BiOBr and free carboxyl groups of MC-LR. This unusual decarboxylation behavior seems to be associated with the particular valence band and conduction band state of BiOBr photocatalyst. Also under BiOBr catalysis, a very stable guanidine group of l-arginine (l-Arg) that is nonreactive with TiO2 photocatalysis is converted to an amino group and subsequently oxidized to a nitro group during the decomposition of MC-LR. This reaction sequence is also related to decarboxylation because the guanidine conversion requires a completely or partially decarboxylated precursor. Our results indicate that BiOBr, a photocatalyst that selectively destroys sites crucial to MC-LR toxicity, shows great promise as a means of effectively treating drinking water.
Subject(s)
Bismuth/chemistry , Microcystins/chemistry , Water Purification/methods , Catalysis , Decarboxylation , Hydroxyl Radical/chemistry , Light , Marine Toxins , Oxidation-Reduction , Photochemistry , Water Pollutants, Chemical/chemistryABSTRACT
Objective To investigate the expression of RECK gene in placentas of patients with preeclampsia and its correlation with MMP-2 activation,and explore the possible roles of RECK gene in the placental trophoblast invasion mechanism.Methods RT-PCR and Western blot were used to detect the expression of RECK mRNA and protein respectively in the placental tissues of normal late pregnant women (normal pregnant group,22 cases) and pre-eclamptic patients(22 mild cases and 20 severe cases).Gelatinase zymography was used to determine MMP-2 activation ratio.Results The expression levels of RECK mRNA and protein from placenta tissues in mild,severe pre-eclamptic group were both significantly higher than those in nomal pregnant group.Moreover,the expression levels of RECK mRNA and protein in severe pre-eclamptic group were obviously increased as compared with those in mild pre-eclamptic group.There was significant difference among the three groups (all P<0.01).MMP-2 activation ratio in mild,severe pre-eclamptic group was significantly lower than that in normal pregnant group.MMP-2 activation ratio in severe pre-eclamptie groups was obviously reduced as compared with mild pre-eclamptic group.There was significant difference among the three groups(all P<0.01).The expression leVels of RECK mRNA and protein were significantly negatively correlated with MMP-2 activation ratio (both P<0.01).Conclusion The abnormal high expression of RECK and inhibition of MMP-2 activation in placentas of pre-eclamptic patients may participate in the process of placental trophoblast shallow invasion.
ABSTRACT
Objective To evaluate the diagnosis and differentiation of solitary pulmonary nodule (SPN) using dynamic spiral CT scan of thin collimation.Methods The thin collimation no-enhanced CT scan and contrast enhanced scan in 30 seconds,1 minute,1 minutes,2 minutes,5 minutes,10 minutes,and 15 minutes after administration of media 100 ml were performed in 38 cases. Results The mean enhanced CT numbers of lung cancer and inflammatory pseudotumor were much higher than that of tuberculosis(TB) and hamartoma and statistically significant in different time of enhancement;20 HU was the threshold for a positive test,the sensitivity was 100% and the specificity was 96%.In time-attenuation curve analysis,lung cancer reached peak enhancement about 2 minutes,inflammatory pseudotumor in 5 minutes and keep longer enhanced time than that of lung cancer.No marked enhancement in SPN of TB and harmatoma,but ring-shaped enhancement can be seen in some of TB.More valuable imaging signs were found with thin collimation scan and more accurate to measure the CT numbers than traditional scan.Conclusion Dynamic spiral CT scan of thin collimation is a very valuable method for diagnosis and differentiation of SPN.
ABSTRACT
The enzyme catalytic reaction properties of H2O2-4-aminoantipyrine (4-AAP)-the different chlorophenolic derivatives color systems using hemoglobin as enzyme mimetic of peroxidase was studied. Meanwhile, the relationship of structure-effect for the different chlorophenolic derivatives as substrate has been discussed, and the mechanism of catalytic reaction has also been investigated. The method for the determination of hydrogen peroxide was proposed using 4-AAP-2,3,4-trichlorophenol system with hemoglobin as catalyst. The sensitivity of method proposed for the determination of H2O2 was better than other similar systems. The apparent molar absorptivity of the chromogenic reaction for H2O2 was 2.21×104 L*mol-1*cm-1. Satisfied results were obtained in the determination of H2O2 in synthetic samples by this method. Also, the method was coupled with glucose oxidation reaction for the determination of glucose in human serum.
