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Find video protocols related to scientific articles indexed in Pubmed.
Analysis of PAEs in semen of infertile men.
Int J Occup Environ Health
PUBLISHED: 11-11-2014
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Objectives: Phthalates are environmental chemicals with reproductive toxicity and estrogenic effects in animals. They are of increasing concern to human health. Aim: To determine whether phthalate levels in semen were associated with infertility. Methods: Using semen samples from 107 infertile and 94 fertile men, the presence and quantity of five phthalate esters were measured using high-performance liquid chromatography (HPLC). Using data collected from questionnaires and clinical examinations, the correlation between phthalate exposure and semen quality was analyzed. Results: The cumulative levels of the measured phthalate esters were significantly higher in the infertility group compared to the control group (P<0·05). Concentrations of the five phthalate esters in men varied by age with older men showing higher cumulative levels. Conclusions: The presence of phthalates may contribute to male infertility in our study population.
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Selective sulfonylation and diazotization of indoles.
Chem. Commun. (Camb.)
PUBLISHED: 10-16-2014
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A metal-free synthesis of bifunctionalized indole derivatives was developed through a novel TBHP/TBAI-mediated oxidative coupling of C2,C3-unsubstituted indoles with arylsulfonyl hydrazide. Under the same conditions C3-methyl substituted indoles underwent a diazotization process, affording 2-sulfonyldiazenyl-1H-indoles. The former reaction simultaneously established C-S and C-N bonds through selective sulfonylation and diazotization of the indole framework, enabling a mild and practical access to polyfunctionalized indoles with good to excellent yields.
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Comparison of pharmacodynamics between low dose ticagrelor and clopidogrel after loading and maintenance doses in healthy Korean subjects.
Platelets
PUBLISHED: 10-03-2014
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Abstract The novel antiplatelet agent ticagrelor has been demonstrated to exert a faster and more powerful inhibition of platelet aggregation in comparison to clopidogrel in coronary artery disease patients. However, a ticagrelor dose of 90?mg twice daily might not be suitable for patients of East Asian ethnicity, and has not been fully investigated. The aim of this study was to assess the effects of low loading doses (LD, 90?mg) and maintenance doses (MD, 90?mg daily) of ticagrelor in comparison to clopidogrel (600?mg LD, 75?mg daily MD) in healthy Korean volunteers. Twelve subjects were randomized into two groups, receiving either clopidogrel (600?mg LD, followed by 75?mg MD daily for 5 days) or ticagrelor (90?mg LD, followed by 90?mg MD daily for 5 days). Following a 2-week washout period, the treatments were switched between the groups. Three platelet function assessment methods which included light transmission aggregometry (LTA), the VerifyNow assay and multiple electrode platelet aggregometry (MEA) were then used to serially measure platelet function at various time points (baseline, 0.5, 2, 6, 24, 26, 120 and 122?h). The mean IPA to 10?µM ADP in the ticagrelor group was significantly higher than that for the clopidogrel group at the 0.5, 2, 6, 26 and 122?h time points (p???0.001). However, there was no significant difference between the two groups at the 24- and 120-hour time points (p?>?0.05). The assay results produced by the other two platelet function tests (VerifyNow and MEA) were similar to those obtained by LTA. The low loading and maintenance doses of ticagrelor (90?mg LD, 90?mg daily MD) cause a more rapid and potent inhibition of platelet function when compared to clopidogrel (600?mg LD and 75?mg MD). Additionally, at the lowest value of platelet inhibition strength, oral once-daily administration of ticagrelor was no less efficacious than clopidogrel at the 24- and 120-hour time points. Due to a large diurnal variation occurring with a single daily dose, a lower dose twice-daily could be a better option for patients of East Asian ethnicity.
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[Soil fertility characteristics under different land use patterns in depressions between karst hills].
Ying Yong Sheng Tai Xue Bao
PUBLISHED: 09-17-2014
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Soil samples were collected from the depressions between karst hills by grid sampling method (5 m x 5 m), soil pH, soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP), and available potassium (AK) in surface layer (0-20 cm) under different land use patterns (burning, cutting, cutting plus root removal, enclosure, maize plantation, and pasture plantation) were measured, the main factors of influencing the soil fertility was identified by principal component analysis (PCA), and the relationships between soil nutrients and microorganisms were demonstrated by canonical correlation analysis (CCA). The results showed that the soil was slightly alkaline (pH 7.83-7.98), and the soil fertility differed under the different land use patterns, with 76.78-116.05 g x kg(-1) of SOC, 4.29-6.23 g x kg(-1) of TN, 1.15-1.47 g x kg(-1) of TP, 3.59-6.05 g x kg(-1) of TK, 331.49-505.49 mg x kg(-1) of AN), 3.92-10.91 mg x kg(-1) of AP, and 136.28-198.10 mg x kg(-1) of AK. These soil indexes except pH showed moderate or strong variation. Different land use patterns had various impacts on soil fertility: Soil nutrients such as SOC, TN, TP, and AN were most significantly influenced by land use patterns in the depressions between karst hills; Followed by soil microorganisms, especially soil actinomycetes, and the effect decreased with the increasing gradient of human disturbance from enclosure, burning, cutting, cutting plus root removal, pasture plantation, and maize plantation. CCA elucidated that considerable interactions existed in soil TP with MBP (microbial biomass phosphorus), TK with MBC (microbial biomass carbon), TN with actinomycetes in the burned area, while TN and MBC in the cutting treatment, AP and MBN (microbial biomass nitrogen) in the treatment of cutting plus root removal, pH with MBC and fungus in the enclosure treatment, TN and TK with MBP in the maize plantation, pH with fungi and actinomycetes in the pasture plantation. Land use patterns changed the soil fertility in the depressions between karst hills; therefore, in the ecological restoration and reconstruction of karst region with fragmented landforms and shallow soil, rational land use patterns should be adopted to improve the soil quality of degraded ecosystems.
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[Effect of medicines for activating blood and reinforcing Qi on angiogenesis in infarcted myocardium edge area of acute myocardial infarction model in rats].
Zhongguo Zhong Yao Za Zhi
PUBLISHED: 09-11-2014
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To study the effect of medicines for activating blood and reinforcing Qi on the number of new micro-vessels and the protein expressions of VEGF and bFGF in the infarcted myocardium edge area of acute myocardial infarction (AMI) model in rats.
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Experimental and Computational Studies on the Reactivity of a Terminal Thorium Imidometallocene towards Organic Azides and Diazoalkanes.
Angew. Chem. Int. Ed. Engl.
PUBLISHED: 08-28-2014
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The reaction of the base-free terminal thorium imido complex [{?(5) -1,2,4-(Me3 C)3 C5 H2 }2 Th?N(p-tolyl)] (1) with p-azidotoluene yielded irreversibly the tetraazametallacyclopentene [{?(5) -1,2,4-(Me3 C)3 C5 H2 }2 Th{N(p-tolyl)N?N?N(p-tolyl)}] (2), whereas the bridging imido complex [{[?(5) -1,2,4-(Me3 C)3 C5 H2 ]Th(N3 )2 }2 {?-N(p-tolyl)}2 ][(n-C4 H9 )4 N]2 (3) was isolated from the reaction of 1 with [(n-C4 H9 )4 N]N3 . Unexpectedly, upon the treatment of 1 with 9-diazofluorene, the NN bond was cleaved, an N?atom was transferred, and the ?(2) -diazenido iminato complex [{?(5) -1,2,4-(Me3 C)3 C5 H2 }2 Th{?(2) -[N?N(p-tolyl)]}{N?(9-C13 H8 )}] (4) was formed. In contrast, the reaction of 1 with Me3 SiCHN2 gave the nitrilimido complex [{?(5) -1,2,4-(Me3 C)3 C5 H2 }2 Th{NH(p-tolyl)}{N2 CSiMe3 }] (5), which slowly converted into [{?(5) -1,2,4-(Me3 C)3 C5 H2 }{?(5) :?-N-1,2-(Me3 C)2 -4-CMe2 (CH2 NN?CHSiMe3 )C5 H2 }Th{NH(p-tolyl)}] (6) by intramolecular C?H bond activation. The experimental results are complemented by density functional theory (DFT) studies.
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The performance of a diabetic retinopathy risk score for screening for diabetic retinopathy in Chinese overweight/obese patients with type 2 diabetes mellitus.
Ann. Med.
PUBLISHED: 08-04-2014
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Diabetic retinopathy (DR) is a common chronic microvascular diabetic complication. The presence of DR may indicate microcirculatory dysfunction in other organ systems besides visual morbidity. The objective of this study was to develop a simple diabetic retinopathy risk score to identify DR in Chinese overweight/obese patients with type 2 diabetes mellitus (T2DM).
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Additive-controlled stereoselective glycosylations of 2,3-oxazolidinone protected glucosamine or galactosamine thioglycoside donors with phenols based on preactivation protocol.
Carbohydr. Res.
PUBLISHED: 07-17-2014
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Stereo-controllable glycosylation reactions of 2,3-oxazolidinone protected glucosamine thioglycoside donor with different phenol acceptors based on preactivation protocol, are described. It was found that BF3·Et2O worked as ?-directing additive, while TTBP acted as ?-directing additive. Simply by altering additives, either ?-aryl glycosides or ?-aryl glycosides were achieved in a stereoselective manner. The additives were also applied to the stereoselective glycosylation reactions of 2,3-oxazolidinone protected galactosamine donor with phenol substrates.
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[Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].
Ying Yong Sheng Tai Xue Bao
PUBLISHED: 07-12-2014
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Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.
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[Optimal cut-off value of phalangeal radiographic absorptiometry to identify osteoporosis in postmenopausal women].
Sichuan Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 06-20-2014
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To study the optimal cut-off value of phalangeal radiographic absorptiometry (RA) to identify osteoporosis in postmenopausal women.
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DFT calculations on kinetic data for some [4+2] reactions in solution.
Phys Chem Chem Phys
PUBLISHED: 06-17-2014
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The reaction mechanisms of [4+2] cycloaddition reactions between dienes and dienophiles have been investigated with several density functional theory (DFT) methods, such as CAM-B3LYP, BMK, M062x wB97x and wB97xd, and the obtained results show that most of the reactions are synchronous or asynchronous. The stability of the transition state is moderated by the interaction of frontier molecular orbitals (FMOs), in which a diene acts as an electron-donating partner and a dienophile acts as an electron-acceptor from the charge transfer direction in the transition state. The activation free energy barriers have been calculated with both gas-phase translational entropy and solution translational entropy, in which those from gas-phase translational entropy (output of the Gaussian job) are far away from the experimental estimations. It has been found that free-energy barriers generated from solution translational entropies with CAM-B3LYP+IDSCRF/6-31G(d), BMK+IDSCRF/6-31G(d) and wB97x+IDSCRF/6-31G(d) are very close to the experimental measurements, but both M062x and wB97xd methods predict too low free-energy barriers for most of the studied reactions. The substituent and solvent effects on reaction dynamic data have also been addressed.
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Characterization of bacteria in the rhizosphere soils of Polygonum pubescens and their potential in promoting growth and Cd, Pb, Zn uptake by Brassica napus.
Int J Phytoremediation
PUBLISHED: 06-11-2014
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Microbe-enhanced phytoremediation has been considered as a promising measure for the remediation of metal-contaminated soils. In this study, two bacterial strains JYX7 and JYX10 were isolated from rhizosphere soils of Polygonum pubescens grown in metal-polluted soil and identified as of Enterobacter sp. and Klebsiella sp. based on 16S rDNA sequences, respectively. JYX7 and JYX10 showed high Cd, Pb and Zn tolerance and increased water-soluble Cd, Pb and Zn concentrations in culture solution and metal-added soils. Two isolates produced plant growth-promoting substances such as indole acetic acid, siderophore, 1-aminocyclopropane-1-carboxylic deaminase, and solubilized inorganic phosphate. Based upon their ability in metal tolerance and solubilization, two isolates were further studied for their effects on growth and accumulation of Cd, Pb, and Zn in Brassica napus (rape) by pot experiments. Rapes inoculated with JYX7 and JYX10 had significantly higher dry weights, concentrations and uptakes of Cd, Pb, Zn in both above-ground and root tissues than those without inoculation grown in soils amended with Cd (25 mg kg(-1)), Pb (200 mg kg(-1)) or Zn (200 mg kg(-1)). The present results demonstrated that JYX7 and JYX10 are valuable microorganism, which can improve the efficiency of phytoremediation in soils polluted by Cd, Pb, and Zn.
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LRP5 polymorphisms and response to alendronate treatment in Chinese postmenopausal women with osteoporosis.
Pharmacogenomics
PUBLISHED: 06-05-2014
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To investigate the association between LRP5 gene polymorphisms and response to alendronate in Chinese osteoporotic women.
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Dermatosis as the initial presentation of gastric cancer: two cases.
Chin. J. Cancer Res.
PUBLISHED: 05-18-2014
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Paraneoplastic dermatoses are known to be certain dermatosis related with tumor. The common paraneoplastic dermatoses are acanthosis nigricans, acquired ichthyosis, dermatomyositis, erythroderma, and so on. Here we report two cases of paraneoplastic dermatoses associated with gastric cancer. One case was a 57-year-old man with dermatomyositis and proved to be associated with gastric cancer through stomachoscopy. The other was a 66-year-old man with erythroderma and proved to be associated with gastric cancer through stomachoscopy. Both cases were treated with radical total gastrectomy with lymphadenectomy (D2) and esophagojejunostomy of Roux-en-Y. The skin symptom of both cases had improved a lot but still existed after operation. Paraneoplastic dermatoses can be seen as the early manifestation of visceral carcinomas. As a result, gastric cancers should be excluded in the patients with paraneoplastic dermatoses.
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The rational design of a highly sensitive and selective fluorogenic probe for detecting nitric oxide.
Chem. Commun. (Camb.)
PUBLISHED: 05-12-2014
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A rationally designed small-molecule fluorogenic probe for nitric oxide (NO) detection based on a new switching mechanism has been developed. Attaching a NO-responsive dihydropyridine pendant group to a fluorophore led to a probe that displays a very high sensitivity to NO concentrations down to the low nM range and a very high specificity to NO while being insensitive to other oxidative oxygen/nitrogen species that often interfere with the sensing of NO.
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"Ring opening-ring closure" strategy for the synthesis of aryl-C-glycosides.
J. Org. Chem.
PUBLISHED: 05-05-2014
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A new "ring-opening-ring closure" strategy for the synthesis of aryl-C-glycosides was described. This strategy exploited the nickel-catalyzed regioselective ?-O elimination of glycals by reactions with various aryl boronic acids or potassium aryltrifluoroborates to yield the ring-opened products, which underwent the Lewis acid, protonic acid, PhSeCl, or NBS mediated ring closure reactions to afford diverse aryl-C-glycosides. After Lewis acids and protonic acids were screened, it was found that, starting from the ring-opened substrates, the Ph3PHBr or Sc(OTf)3 mediated ring closure reaction provided ?- or ?-preferred aryl-C-?(2,3)-glycosides, respectively. Furthermore, ?-D-phenyl-C-glycosides were successfully prepared via the PhSeCl-mediated cyclization reaction, whereas the ?-D-phenyl-C-glycoside was obtained via the NBS-mediated cyclization reaction. After removal of the 2-substituted functionalities by Bu3SnH/AIBN, the synthesis of 2-deoxy-aryl-C-glycosides was ultimately realized in a stereoselective manner.
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Vagal baroreflex activation resulting in acute coronary stent thrombus associated with myocardial infarction: a case report.
BMC Cardiovasc Disord
PUBLISHED: 04-11-2014
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Percutaneous coronary intervention with stenting in patients with coronary atheromatous stenosis carry an inherent risk of affecting the baroreflex-mediated regulation of hemodynamic alterations, especially for heart rate and blood pressure. To the best of our knowledge, the vagal baroreflex activation associated with acute coronary stent thrombosis in patients who have undergone percutaneous coronary intervention has not been previously reported.
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Expression of serum miR-16, let-7f, and miR-21 in patients with hepatocellular carcinoma and their clinical significances.
Clin. Lab.
PUBLISHED: 04-05-2014
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Recent studies showed that serum microRNAs were aberrantly expressed in cancers, including hepatocellular carcinoma (HCC). Serum microRNA (miRNA) profiles in HCC have been filtered in our previous studies. In this research, some serum miRNAs were further validated and their clinical significances were analyzed.
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A highly selective and sensitive Zn(II) complex-based chemosensor for sequential recognition of Cu(II) and cyanide.
Dalton Trans
PUBLISHED: 04-01-2014
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Two new Schiff base complexes, [ZnL(Ac)]2 (1) and [CuLCl]·H2O (2) (HL = 2-(2'-hydroxynaphthylmethylene)aminophenylbenzimidazole, Ac = acetate) were synthesized by a one-pot reaction and characterized by elemental analyses, IR and single-crystal X-ray diffraction. Fluorescence of complex 1 showed "on-off-on" switching when Cu(2+) and cyanide were sequentially detected. This phenomenon was investigated by UV-Vis absorption, fluorescence and ESI-MS spectra, and theoretical calculations to explain the response. Complex 1 can selectively respond to Cu(2+) with the fluorescence "turn-off" owing to the formation of complex 2 in the solution. Interestingly, the quenched fluorescence of complex 1 by Cu(2+) ions could be turned on after the addition of cyanide owing to the displacement of L(-) by CN(-) to form [Cu(CN)x](n-), making complex 1 a selective CN(-) probe. In addition, the results of the MTT assay experiment indicate that complex 1 has a low toxicity to cells and can be used to detect intracellular Cu(2+) ion by live cell imaging.
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GGPPS1 predicts the biological character of hepatocellular carcinoma in patients with cirrhosis.
BMC Cancer
PUBLISHED: 03-12-2014
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Hepatocellular carcinoma (HCC) has been associated with diabetes and obesity, but a possible connection with the metabolic syndrome (MetS) and its potential interaction with hepatitis and cirrhosis are open to discussion. Our previous investigations have shown that GGPPS1 plays a critical role during hyperinsulinism. In this report, the expression and distribution of GGPPS1 in liver cancer, and its clinical significance were investigated.
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Better inflation time of stent balloon for second-generation drug-eluting stent expansion and apposition: an optical coherence tomography study.
J Interv Cardiol
PUBLISHED: 03-05-2014
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We tried to determine the effect of stent balloon inflation time on stent expansion and apposition using optical coherence tomography.
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A highly selective chemosensor for Al(III) and Zn(II) and its coordination with metal ions.
Inorg Chem
PUBLISHED: 02-26-2014
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This paper reports a fluorescence chemosensor, N-(benzimidazol-2-yl)salicylaldimine (H2L), for Zn(II) and Al(III) ions. H2L has high selectivity for Al(III) in dimethyl sulfoxide (DMSO) and for Zn(II) in N,N-dimethylformamide (DMF). In methanol, Zn(II) and Al(III) could also be distinguished by H2L with different excitation wavelengths. The fluorescent species [Zn(HL)(H2O)(CH3OH)](+), [Zn(HL)(H2O)(DMF)](+), [Al(HL)2(OH)(H2O)], and [Al(HL)(OH)2(H2O)(DMSO)] formed in solution were established by a combination of experimental and theoretical methods, including Job's plot, (1)H NMR titration, electrospray inonization mass spectrometry (ESI-MS), and B3LYP-SCRF/6-31(d) and TD-B3LYP-SCRF/6-31G* density functional theory methods. The results show that Zn(II) and Al(III) are all coordinated to the imine nitrogen atom and the hydroxyl oxygen atom from H2L, which is the same as the M(2+) ions in the obtained mononuclear complexes [M(HL)2(CH3OH)2] (where M = Cd, Ni, Co, and Mg). The detection limits of H2L for Zn(II) were 5.98 ?M in methanol and 5.76 ?M in DMF, while the detection limits of H2L for Al(III) were 3.3 ?M in methanol and 5.25 ?M in DMSO. Furthermore, it is also confirmed that H2L has low toxicity for HeLa cells and could be used to detect Zn(II) and Al(III) ions in living cells by bioimaging.
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Multi-modality imaging for stent edge assessment.
Heart Vessels
PUBLISHED: 01-10-2014
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Optical coherence tomography (OCT) has a sufficiently high resolution to allow assessment of stent edge dissection (ED). The aims of the present study were as follows: (1) evaluation of the frequency of stent ED using OCT; (2) comparison of stent ED detection rates obtained using angiography, intravascular ultrasound (IVUS), and OCT; and (3) IVUS-Virtual Histology (IVUS-VH) evaluation of plaque composition at the site of stent EDs detected by OCT after percutaneous coronary intervention (PCI). Fifty-eight consecutive patients (59 lesions, 100 stent edges) who underwent balloon-expandable stent implantation and post-stent assessment with OCT and IVUS-VH were included. OCT revealed stent ED in 24.0 % (24 of 100) of stent edges after PCI with a balloon-expandable stent. In contrast, ED was detected in only 3.0 % (3 of 100) of stent edges using angiography and 4.0 % (4 of 100) of stent edges using IVUS. Plaque evaluation using IVUS-VH showed that the percent necrotic core (21.2 ± 8.3 vs. 13.4 ± 10.7 %, p = 0.001) and absolute dense calcium (2.9 ± 2.4 vs. 1.3 ± 2.2 mm(3), p = 0.0104) and dense calcium (13.8 ± 9.3 vs. 5.4 ± 5.8 %, p < 0.001) volumes were greater in the ED group than in the non-ED group. Thus, OCT is superior to conventional coronary angiography and IVUS in the identification of stent ED. In addition, the plaque composition at the ED site is characterized by a necrotic core and greater dense calcium levels than those observed at the non-ED site.
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N-arylated-lactam-type iminosugars as new immunosuppressive agents: discovery, optimization, and biological evaluation.
Chem Asian J
PUBLISHED: 01-04-2014
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We have previously described the discovery of N-alkylated iminosugars that showed immunosuppressive activity both in?vitro and in?vivo. Herein, we report the synthesis and biological evaluation of N-arylated lactam-type iminosugar derivatives. The synthesis started from simple monosaccharides and featured a Buchwald-Hartwig coupling reaction to construct the key N-aryl connection, thereby providing a highly diverse compound library. Structure-activity relationship studies, guided by a mouse-spleen-proliferation assay, led to the identification of 'hit' compound 12?f. Subsequently, the systematic modification of compound 12?f afforded compounds 21?h, 21?k, 21?n, 21?t, and 21?x with improved activities (IC50 =12-30??M) and low Jurkat cytotoxicities (IC50 >100??M). These new compounds also inhibited the secretion of IFN-? and IL-4, which are hallmark cytokines of Th1 and Th2 cells, respectively. This work demonstrated that the N-arylated iminosugar structure represents a new scaffold with immunosuppressive activity.
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Effect of low-frequency rTMS on aphasia in stroke patients: a meta-analysis of randomized controlled trials.
PLoS ONE
PUBLISHED: 01-01-2014
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Small clinical trials have reported that low-frequency repetitive transcranial magnetic stimulation (rTMS) might improve language recovery in patients with aphasia after stroke. However, no systematic reviews or meta-analyses studies have investigated the effect of rTMS on aphasia. The objective of this study was to perform a meta-analysis of studies that explored the effects of low-frequency rTMS on aphasia in stroke patients.
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[Prevalence and risk factors for dyslipidemia in diabetics with overweight or obesity].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 12-31-2013
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To explore the prevalence and risk factors for dyslipidemia in diabetics with overweight or obesity.
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Stereoselective Synthesis of the Trisaccharide Moiety of Ganglioside HLG-2.
J. Org. Chem.
PUBLISHED: 12-24-2013
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The glycan portion of ganglioside HLG-2, which was identified in the extracts of the sea cucumber Holothuria leucospilota , was synthesized in a highly efficient and stereoselective manner. The unusual sequence of the trisaccharide moiety, ?-N-glycolylsialyl-(2,4)-?-N-acetylsialyl-(2,6)-glucoside, was assembled by stereoselective coupling of a 5-N,4-O-carbonyl-protected sialyl phosphate donor, a N-2,2,2-trichloroethoxycarbonyl (Troc)-protected sialyl acceptor, and a (trimethylsilyl)ethyl-?-glucosyl acceptor in high yield. The synthesis featured the high-yielding construction of two ?-sialyl linkages.
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Between a reactant rock and a solvent hard place - molecular corrals guide aromatic substitutions.
Phys Chem Chem Phys
PUBLISHED: 11-28-2013
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A novel reaction mechanism is presented for an ortho-magnesium carboxylate driven aromatic nucleophilic substitution in naphthoic acids, supported by high-level density functional theory. Results show that the rate-determining aspects involve an R-group transfer from a Grignard reagent Mg-atom to the C1-atom on a naphthalene ring. This transfer is moderated by a molecular corral comprised of two solvent THF molecules and the naphthoic acid, which collectively marshal the R-group into position. The CAM-B3LYP method was employed together with the all-electron DZVP basis set. Solvent was treated using an implicit dielectric continuum (PCM method) and IDSCRF atomic-radii. Further evolved solvent models were also investigated, consisting of explicit solvating particles forming a primary solvation layer framing the reaction center. Reaction barriers obtained are in close agreement with experimental trends, with R-group substituent-identity tempering repulsion with the molecular corral, in-turn modulating the free-energy barriers. Partitioning of the dynamic bases of entropy contribution to free-energy was central to the successful experimental-theoretical synergy.
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Prevalence and determinants of hyperuricemia in type 2 diabetes mellitus patients with central obesity in Guangdong Province in China.
Asia Pac J Clin Nutr
PUBLISHED: 11-16-2013
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This study investigated the prevalence and determinants of hyperuricemia in Chinese type 2 diabetes mellitus (T2DM) patients with central obesity. A multicentric hospital-based cross-sectional study was carried out in Guangdong Province between August 2011 and March 2012. At each hospital, Chinese T2DM patients with central obesity who were aged over 20 years, whose serum uric acid levels were measured, and who had lived in Guangdong Province for >=1 year, were recruited. Hyperuricemia was defined as serum uric acid >420 ?mol/L in men and >360 ?mol/L in women. Binary logistic regression was used to assess associated risk factors for hyperu-ricemia. A total of 2,917 T2DM patients with central obesity took part. The overall prevalence of hyperuricemia was 32.6% (36.1% for women, 28.4% for men). Binary logistic regression analyses demonstrated that women (OR: 1.576; 95% confidence interval (CI): 1.231, 2.018), high BMI (OR: 1.228; 95% CI: 1.094, 1.379), waist cir-cumference (OR: 1.135; 95% CI: 1.009, 1.276), hypertension (OR: 1.603; 95% CI: 1.263, 2.035), high total cho-lesterol (OR: 1.133; 95% CI: 1.002, 1.281), triglycerides (OR: 1.134; 95% CI: 1.069, 1.203), low HDL-cholesterol (OR: 0.820; 95% CI: 0.677, 0.995) and low estimated glomerular filtration rate (OR: 0.840; 95% CI: 0.815, 0.866) were risk factors associated with hyperuricemia. Hyperuricemia is prevalent in Chinese T2DM patients with central obesity and is significantly positively associated with women, cardiovascular risk factors such as obesity, hypertension and dyslipidemia, and low eGFR.
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ortho-Methylphenylthioglycosides as glycosyl building blocks for preactivation-based oligosaccharide synthesis.
Carbohydr. Res.
PUBLISHED: 10-29-2013
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Thioglycosides are widely used in orthogonal glycosylation, armed-disarmed chemoselective glycosylation, and preactivation-based glycosylation. Nevertheless, aglycon transfer occasionally occurred in the glycosylation process of thioglycosides. This problem was also encountered in preactivation-based reactions, which limited the applications of preactivation-based glycosylation to some extent. To tackle this problem, sterically hindered aglycon ortho-methylphenylthioglycosides were introduced as glycosyl building blocks. These thioglycosides prevented the aglycon transfer and enhanced the efficiency of glycosyl coupling reactions, especially in the reactions of disarmed donors with armed acceptors. Moreover, these thioglycosides were employed in preactivation-based one-pot oligosaccharide assembly.
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Risk assessment in patients undergoing liver resection.
HBPD INT
PUBLISHED: 10-10-2013
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Liver resection is still a risky procedure with high morbidity and mortality. It is significant to predict the morbidity and mortality with some models after liver resection.
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[A cross-sectional survey of blood pressure control in overweight or obese type 2 diabetic patients in Guangdong province].
Zhonghua Nei Ke Za Zhi
PUBLISHED: 09-25-2013
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To investigate the current situation and influential factors of blood pressure (BP) control in type 2 diabetic patients with overweight or obesity in Guangdong province.
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[Risk factors of acute-phase response following the first-dose administration of zoledronic acid in the treatment of osteoporosis].
Sichuan Da Xue Xue Bao Yi Xue Ban
PUBLISHED: 09-25-2013
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Objective To explore the risk factors of acute-phase response (APR) following the first-dose administration of zoledronic acid in the treatment of osteoporosis.
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[Diversity of culturable filamentous bacteria in the activated sludge from A2O wastewater treatment process].
Huan Jing Ke Xue
PUBLISHED: 09-14-2013
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The anoxic-anaerobic-oxic (A2O) process is widely used in wastewater treatment plant, however, sludge bulking and foaming are the most frequent operational problems in this process. Activated sludge bulking is caused by the overgrowth of some types of filamentous bacteria, especially Microthrix parvicella. In the study, 17 strains of filamentous bacteria were isolated from the bulking sludge of A2O process using Gauses medium. The 16S rRNA genes of the 17 isolates were sequenced to analyze their diversity. The results showed all of the 17 isolates were Streptomyces. Further analysis of these strains by the repetitive sequence based on polymerase chain reaction (rep-PCR) technology showed that there was a high diversity in these isolated Streptomyces. The physiological properties of them were different from Microthrix parvicella. The settleability of activated sludge was improved when some of the isolates were inoculated.
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Cancer stem-like cell characteristics induced by EB virus-encoded LMP1 contribute to radioresistance in nasopharyngeal carcinoma by suppressing the p53-mediated apoptosis pathway.
Cancer Lett.
PUBLISHED: 09-13-2013
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Emerging evidence confirms that cancer stem cells (CSCs) are responsible for the chemoradioresistance of malignancies. EBV-encoded latent membrane protein 1 (LMP1) is associated with tumor relapse and poor prognosis of nasopharyngeal carcinoma (NPC). However, whether LMP1 induces the development of CSCs and the mechanism by which this rare cell subpopulation leads to radioresistance in NPC remain unclear. In the present study, LMP1-transformed NPC cells showed significant radioresistance compared to the empty vector control. We found that LMP1 up-regulated the expression of several stemness-related genes, increased the cell number of side population (SP) by flow cytometry analysis, enhanced the self-renewal properties of the cells in a spherical culture and enhanced the in vivo tumor initiation ability. We also found that LMP1 positively regulated the expression of the CSC marker CD44. The CD44(+/High) subpopulation of the LMP1-transformed NPC cells displayed more significant CSC characteristics than the CD44(-/Low) subpopulation of the LMP1-transformed NPC cells; these characteristics included the upregulation of stemness-related genes, in vitro self-renewal and in vivo tumor initiation ability. Importantly, the CD44(+/High) subpopulation displayed more radioresistance than the CD44(-/Low) subpopulation. Our results also demonstrated that phosphorylation of the DNA damage response (DDR) proteins, ATM, Chk1, Chk2 and p53, was inactivated in the LMP1-induced CD44(+/High) cells in response to DNA damage, and this was accompanied by a downregulation of the p53-targeted proapoptotic genes, which suggested that the inactivation of the p53-mediated apoptosis pathway was responsible for the radioresistance in the CD44(+/High) cells. Taken together, we found that LMP1 induced an increase in CSC-like CD44(+/High) cells, and we determined the molecular mechanism underlying the radioresistance of the LMP1-activated CSCs, highlighting the need of CSC-targeted radiotherapy in EBV-positive NPC.
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Pd(OAc)2-catalyzed C-H activation/C-O cyclization: mechanism, role of oxidant-probed by density functional theory.
J. Org. Chem.
PUBLISHED: 08-09-2013
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A series of density functional theory determinations have been carried out to characterize Pd(OAc)2-catalyzed C-H activation and subsequent intramolecular C-O bond-coupling of phenyl-tert-butanol in perfluorobenzene (C6F6) solvent. Full, nontruncated models of the real chemical transformations were studied, with structures in agreement with recent X-ray determinations. Conformational analyses have provided thermodynamic validity of the geometric structures used. The B3LYP/DZVP and B3LYP/BS1 methods (BS1 = TZVP(H,C,O) + SDD(Pd,I)) were comparatively employed, with C6F6 solvent contributions accounted for by the IDSCRF method; key transition states were confirmed by intrinsic reaction coordinate determinations. The novel reaction mechanism proposed was divided into the following four steps: C-H activation, oxidation, reductive elimination, catalyst recovery. Two competing reaction routes were quantitatively compared, differing in the oxidation state of Pd (+2 vs +4). Results reveal the pathway involving Pd(IV) intermediates to be more spontaneous and, therefore, more probable than the Pd(II) path, the latter hindered by a kinetically inaccessible reductive elimination step, with total energy and free energy barriers of 41.0 and 38.6 kcal·mol(-1), respectively. The roles played by the oxidant and Pd(IV) species have also been addressed through Baders atoms-in-molecules wave function analyses, providing a quantitative electronic metric for C-H activation chemistry.
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The posterolateral mid-forearm perforator flap: Anatomical study and clinical application.
Microsurgery
PUBLISHED: 07-17-2013
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Defects sustained at the distal forearm are common and pedicled perforator flaps have unique advantages in resurfacing it. The purpose of this study is to reappraise the anatomy of the perforator in the posterolateral aspect of the mid-forearm and present our clinical experience on using perforator flaps based on it for reconstruction of defects in the distal forearm. Methods: This study was divided into anatomical study and clinical application. In the anatomical study, 30 preserved upper limbs were used. Clinically, 11 patients with defects at the forearm underwent reconstruction with the posterolateral mid-forearm perforator flaps. The defects, ranging from 4.5 × 2.5 cm to 10.5 × 4.5 cm, were located at the dorsal aspect of the distal forearm in 6 cases and at the volar aspect of the distal forearm in 5 cases.
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Prevalence and risk factors for diabetic retinopathy in a high-risk Chinese population.
BMC Public Health
PUBLISHED: 07-02-2013
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Lifestyle plays an important role in the development of diabetic retinopathy. The lifestyle in Guangzhou is different from other cities in China as the Cantonese prefer eating rice porridge, but not spicy foods. The objectives of this study were to investigate the prevalence and determinants of diabetic retinopathy in a high-risk population of Guangzhou.
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2-(1-Methyl-2-oxoindolin-3-yl-idene)malono-nitrile.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 07-01-2013
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The title mol-ecule, C12H7N3O, is almost planar, with an r.m.s. deviation of 0.026?Å. No directional interactions could be detected in the crystal.
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A highly selective fluorescent chemosensor for Al(III) ion and fluorescent species formed in the solution.
Inorg Chem
PUBLISHED: 06-20-2013
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A chemosensor for the Al(3+) ion, 1-[(3-hydroxypyridin-2-ylamino)methylene]naphthalen-2(1H)-one (H2L), based on inhibited excited-state intramolecular proton transfer was synthesized. The experimental and theoretical calculations at B3LYP+PCM/6-31G(d) revealed that Al(3+) and H2L form a 1:1 complex, [AlL(OH)(H2O)]2, in dimethyl sulfoxide that exhibits two remarkably enhanced fluorescent emissions at 523 and 553 nm. It is confirmed that H2L could be used to detect Al(3+) ions in cells by bioimaging.
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Penicillins catalytic mechanism revealed by inelastic neutrons and quantum chemical theory.
Phys Chem Chem Phys
PUBLISHED: 06-12-2013
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Penicillin, travels through bodily fluids, targeting and acylatively inactivating enzymes responsible for cell-wall synthesis in gram-positive bacteria. Somehow, it avoids metabolic degradation remaining inactive en route. To resolve this ability to switch from a non-active, to a highly reactive form, we investigated the dynamic structure-activity relationship of penicillin by inelastic neutron spectroscopy, reaction kinetics, NMR and multi-scale theoretical modelling (QM/MM and post-HF ab initio). Results show that by a self-activating physiological pH-dependent two-step proton-mediated process, penicillin changes geometry to activate its irreversibly reactive acylation, facilitated by systemic intramolecular energy management and cooperative vibrations. This dynamic mechanism is confirmed by the first ever reported characterisation of an antibiotic by neutrons, achieved on the TOSCA instrument (ISIS facility, RAL, UK).
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5-Methyl-N-(1,3-thia-zol-2-yl)isoxazole-4-carboxamide.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 06-01-2013
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In the title compound, C8H7N3O2S, the dihedral angle between the thia-zol and isoxazole rings is 34.08?(13)°. In the crystal, the mol-ecules are linked by pairs of N-H?N hydrogen bonds, forming inversion dimers, and C-H?O inter-actions, resulting in chains along the b-axis direction.
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Effect of low-dose alendronate treatment on bone mineral density and bone turnover markers in Chinese postmenopausal women with osteopenia and osteoporosis.
Menopause
PUBLISHED: 06-01-2013
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The aim of this study was to evaluate the effect of low-dose alendronate (ALN) treatment on bone mineral density (BMD) and bone turnover markers in Chinese postmenopausal women with osteopenia and osteoporosis.
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HIV Infection and Sexual Behaviors Among Non-Commercial Men Who Have Sex with Men at Different Venues.
Arch Sex Behav
PUBLISHED: 05-12-2013
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The prevalence of HIV infection among men who have sex with men (MSM) has increased rapidly in China. Previous studies suggested that some venue-specific characteristics could significantly affect MSMs sexual behaviors that were related to HIV transmission. Thus, to compare the HIV infection rates and related risky sexual behaviors among MSM at different venues, we conducted a cross-sectional study with time-location sampling in Shenzhen, China. Among the 801 MSM recruited in the study, 7.0 % (n = 56) were found to be HIV positive, with 0.9 % of MSM at bars (BMSM), 3.5 % of MSM at suburban recreational centers (RMSM), 8.1 % of MSM at saunas (SMSM), 9.3 % of MSM at parks (PMSM), and 10.1 % of MSM at dorm-based venues (DMSM). HIV infection was significantly more prevalent in MSM in dorm-based venues, parks, and saunas than in other venues. Compared to MSM in other venues, BMSM were more likely to be single, drug and alcohol users, but less likely to be HIV and syphilis positive. More PMSM reported having unprotected anal intercourse with other men while more SMSM reported having multiple male sex partners and more RMSM had a low level of HIV-related knowledge. The results indicated that MSM frequenting different venues were inconsistent with regards to demographic characteristics, HIV and syphilis infection rates, and risky sexual behaviors. Greater efforts are needed to develop intervention strategies that target specific venues and risky behaviors.
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[A cross-sectional survey on current status of type 2 diabetes mellitus with overweight or obesity in Guangdong province].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 05-08-2013
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To explore the glycemic control status and related risk factors of overweight or obesity patients with type 2 diabetes mellitus (T2DM) in Guangdong province.
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[Ecological-geographic landscapes of natural plague foci in China VIII. Typing of natural plague foci].
Zhonghua Liu Xing Bing Xue Za Zhi
PUBLISHED: 05-08-2013
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Since plague is an important natural focus zoonosis, the typing of natural plague foci becomes one of the elements in understanding the nature and developing related prevention program of the disease. Natural foci of plague are composed by four fundamental parts which include Eco-geographical landscape (natural plague foci), hosts, vectors and pathogens (Yersinia pestis) that comprehensively interact through the large temporal scale of evolution. Human activities have had great impact on the foci of natural plague. Based on the published serial research papers, we tried to integrate the knowledge of each factor in natural plague foci and focusing on theoretical aspects, so as to strengthen the prevention and surveillance programs of plague to be extrapolated to other zoonosis.
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[Choice of macroinvertebrate metrics for constructing a benthic-index of biotic integrity based on the disturbance gradients in the Qinjiang River Basin].
Huan Jing Ke Xue
PUBLISHED: 03-16-2013
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The selection of proper macroinvertebrate metrics was a key step in the successful construction of benthic-index of biotic integrity (B-IBI). In the context of lack of sufficient reference sites, the responses of biotic metrics to the stress gradients have been proved crucially important in metrics selection. We explored this using a data set (twenty-two sampling sites), where water environmental parameters, habitat quality index (HQI) and zoobenthos were measured and sampled using standardized methodology in the winter dry season (January, 2010) within the Qinjiang Rvier basin, Guangxi. Water quality stress gradients were synthesized using principle component analysis. Twelve out of the 38 candidate metrics were excluded because of high co-linearity ( [ r ] > 0.80, P < 0.05) with others. Multiple regression analysis of the rest twenty-six metrics, environmental gradients (PC I and PC II ) and habitat quality index showed that thirteen metrics significantly correlated (P < 0.05) with the environmental stressors (PCs and HQI). Eight of these metrics, family richness, Ephemeroptera richness, Coleoptera richness; Ephemeroptera, Plecoptera and Trichoptera (EPT) abundance, proportion of dominant species; proportion of predators; Shannon-Weaver diversity index for genus; and Biotic index (BI), satisfied the selection criteria (e. g., operational simplicity) and were thus candidates for developing a multimetric system to assess river health in our study region. We suggest that the response of metrics to environmental gradient is an ideal alternative for the construction of benthic-index of biotic integrity in the context of insufficient reference sites.
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Catalytic C-H activation/C-C coupling reaction: DFT studies on the mechanism, solvent effect, and role of additive.
J. Org. Chem.
PUBLISHED: 02-26-2013
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A series of density functional theory (DFT) experiments, employing the B3LYP+IDSCRF/BS1 and B3LYP+IDSCRF/DZVP methods, have been carried out for the Pd(OAc)2-catalyzed enamide-siloxane C-H activation/C-C coupling reactions. The results reveal that there are four processes, namely C-H activation, transmetalation (TM), reductive elimination (RE), and separation of product (SP) and recycling of catalyst (RC), each of which is consist of different steps. In order to fully understand the origin of regiospecific C-H activation/C-C coupling on the alicyclic ring experimentally observed, the conformational preference, kinetic aspects, and relative stabilities of the competitive products have been explored. In addition, the roles of additive silver salt AgF and solvent dioxane have also been addressed, providing valuable details upon which to rationally optimize experimental conditions.
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Laser-induced dissociation of singly protonated peptides at 193 and 266 nm within a hybrid linear ion trap mass spectrometer.
Rapid Commun. Mass Spectrom.
PUBLISHED: 02-08-2013
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We implemented, for the first time, laser-induced dissociation (LID) within a modified hybrid linear ion trap mass spectrometer, QTrap, while preserving the original scanning capabilities and routine performance of the instrument.
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4-Chloro-1-methyl-indoline-2,3-dione.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 12-05-2011
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The title mol-ecule, C(9)H(6)ClNO(2), is essentially planar; the maximum deviation of the indoline ring system is 0.027?(3)?Å and the substituents do not deviate by more than 0.075?(2)?Å from this plane. Inter-molecular C-H?O hydrogen bonds consolidate the crystal structure.
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1-Benzyl-4-chloro-indoline-2,3-dione.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 11-27-2011
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There are two independent mol-ecules in the asymmetric unit of the title compound, C(15)H(10)ClNO(2), which differ in the dihedral angles between the mean planes of the phenyl ring and the 4-chloro-indoline-2,3-dione ring system [59.48?(9) and 79.0?(1)°]. In the crystal, mol-ecules are linked through C-H?O hydrogen bonds, forming polymeric chains in [100].
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6-Chloro-1-methyl-indoline-2,3-dione.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 11-15-2011
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The title mol-ecule, C(9)H(6)ClNO(2), is essentially planar: the maximum deviation from the mean plane of the indoline ring is 0.020?(2)?Å and the substituents do not deviate by more than 0.053?(2)?Å from this plane. C-H?O hydrogen bonds help to consolidate the crystal structure.
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1-Benzyl-6-chloro-indoline-2,3-dione.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 11-15-2011
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In the title compound, C(15)H(10)ClNO(2),the dihedral angle between the mean planes of the benzene and 6-chloro-indoline-2,3-dione ring systems, linked through a methyl-ene group, is 81.68?(10)°. In the crystal, mol-ecules are connected by C-H?O hydrogen bonds, generating C(6) chains propagating in [010].
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N-(4-Chloro-2-nitro-phen-yl)-5-methyl-isoxazole-4-carboxamide.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 11-04-2011
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In the title compound, C(11)H(8)ClN(3)O(4), the dihedral angle between benzene and isoxazole rings is 9.92?(1) °. The nitro group is almost coplanar with the benzene ring with an O-N-C-C torsion angle of 8.4?(3)°. The mol-ecular conformation is stabilized by an intra-molecular N-H?O hydrogen bond, closing a six-membered ring.
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[Dynamic changes of 5-HT, DA and their metabolin in rat striatum during exhaustive exercise and recovery].
Zhongguo Ying Yong Sheng Li Xue Za Zhi
PUBLISHED: 10-31-2011
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To study the dynamic characteristics of serotonin (5-HT), dopamine (DA) and their metabolin changes in brain during the development of exercise-induced central fatigue.
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[Changes of subthalamic nucleus and cortex activity in rat during exhausting exercise].
Zhongguo Ying Yong Sheng Li Xue Za Zhi
PUBLISHED: 10-31-2011
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To observe the modulatory effect of subthalamic nucleus (STN) on activity of motor cortex during exhausting exercise.
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N-(2,6-Dichloro-phen-yl)-5-methyl-1,2-oxazole-4-carboxamide monohydrate.
Acta Crystallogr Sect E Struct Rep Online
PUBLISHED: 10-06-2011
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In the title compound, C(11)H(8)Cl(2)N(2)O(2)·H(2)O, the dihedral angle between the benzene and isoxazole rings is 59.10?(7)°. In the crystal, the components are linked by N-H?O and O-H?O hydrogen bonds into a three-dimensional network. The crystal structure is further stabilized by ?-? stacking inter-actions [centroid-centroid distance = 3.804?(2)?Å].
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The Th=C double bond: an experimental and computational study of thorium poly-carbene complexes.
Dalton Trans
PUBLISHED: 08-04-2011
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The first thorium poly-carbene complexes [(Ph(2)P=S)(2)C](2)Th(DME) (2) and [{[(Ph(2)P=S)(2)C](3)Th}Li(2)(DME)](n) (3) have been prepared and structurally characterized. DFT calculations reveal that the Th=C bond is polarized toward the nucleophilic carbene carbon atom, which is further verified by the experimental observation that the Th=C bond shows a nucleophilic behavior with Ph(2)CO.
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Thorium oxo and sulfido metallocenes: synthesis, structure, reactivity, and computational studies.
J. Am. Chem. Soc.
PUBLISHED: 07-27-2011
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The synthesis, structure, and reactivity of thorium oxo and sulfido metallocenes have been comprehensively studied. Heating of an equimolar mixture of the dimethyl metallocene [?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)](2)ThMe(2) (2) and the bis-amide metallocene [?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)](2)Th(NH-p-tolyl)(2) (3) in refluxing toluene results in the base-free imido thorium metallocene, [?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)](2)Th?N(p-tolyl) (4), which is a useful precursor for the preparation of oxo and sulfido thorium metallocenes [?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)](2)Th?E (E = O (5) and S (15)) by cycloaddition-elimination reaction with Ph(2)C?E (E = O, S) or CS(2). The oxo metallocene 5 acts as a nucleophile toward alkylsilyl halides, while sulfido metallocene 15 does not. The oxo metallocene 5 and sulfido metallocene 15 undergo a [2 + 2] cycloaddition reaction with Ph(2)CO, CS(2), or Ph(2)CS, but they show no reactivity with alkynes. Density functional theory (DFT) studies provide insights into the subtle interplay between steric and electronic effects and rationalize the experimentally observed reactivity patterns. A comparison between Th, U, and group 4 elements shows that Th(4+) behaves more like an actinide than a transition metal.
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New Methods for Labeling RGD Peptides with Bromine-76.
Theranostics
PUBLISHED: 07-23-2011
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Direct bromination of the tyrosine residues of peptides and antibodies with bromine-76, to create probes for PET imaging, has been reported. For peptides that do not contain tyrosine residues, however, a prosthetic group is required to achieve labeling via conjugation to other functional groups such as terminal ?-amines or lysine ?-amines. The goal of this study was to develop new strategies for labeling small peptides with Br-76 using either a direct labeling method or a prosthetic group, depending on the available functional group on the peptides. A new labeling agent, N-succinimidyl-3-[(76)Br]bromo-2,6-dimethoxybenzoate ([(76)Br]SBDMB) was prepared for cyclic RGD peptide labeling. N-succinimidyl-2, 6-dimethoxybenzoate was also used to pre-attach a 2, 6-dimethoxybenzoyl (DMB) moiety to the peptide, which could then be labeled with Br-76. A competitive cell binding assay was performed to determine the binding affinity of the brominated peptides. PET imaging of U87MG human glioblastoma xenografted mice was performed using [(76)Br]-BrE[c(RGDyK)](2) and [(76)Br]-BrDMB-E[c(RGDyK)](2). An ex vivo biodistribution assay was performed to confirm PET quantification. The mechanisms of bromination reaction between DMB-c(RGDyK) and the brominating agent CH(3)COOBr were investigated with the SCRF-B3LYP/6-31G* method with the Gaussian 09 program package. The yield for direct labeling of c(RGDyK) and E[c(RGDyK)](2) using chloramine-T and peracetic acid at ambient temperature was greater than 50%. The yield for [(76)Br]SBDMB was over 60% using peracetic acid. The conjugation yields for labeling c(RGDfK) and c(RGDyK) were over 70% using the prosthetic group at room temperature. Labeling yield for pre-conjugated peptides was over 60%. SDMB conjugation and bromination did not affect the binding affinity of the peptides with integrin receptors. Both [(76)Br]Br-E[c(RGDyK)](2) and [(76)Br]BrDMB-E[c(RGDyK)](2) showed high tumor uptake in U87MG tumor bearing mice. The specificity of the imaging tracers was confirmed by decreased tumor uptake after co-administration of unlabeled dimeric RGD peptides. The energy barrier of the transition state of bromination for the dimethoxybenzoyl group was about 9 kcal/mol lower than that for the tyrosine residue. In conclusion, the newly developed N-succinimidyl-2, 6-dimethoxybenzoate molecule can be used either for one step labeling through pre-conjugation or as the precursor for a Br-76 labeled prosthetic group for indirect labeling. Radiobromination on a dimethoxybenzoyl group has selectivity over radiobromination on tyrosine. The energy barrier difference of the transition states of bromination between the dimethoxybenzoyl group and the tyrosine residue may account for the reaction selectivity when both groups are present in the same molecule.
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A base-free thorium-terminal-imido metallocene: synthesis, structure, and reactivity.
Chemistry
PUBLISHED: 06-27-2011
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The synthesis, structure, and reactivity of a base-free thorium terminal-imido metallocene have been comprehensively studied. Treatment of thorium metallocenes [{?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)ThMe(2)] and [{?(5)-1,3-(Me(3)C)(2)C(5)H(3)}(2)ThMe(2)] with RNH(2) gives diamides [{?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th(NHR)(2)] (R=Me (7), p-tolyl (8)) and [{?(5)-1,3-(Me(3)C)(2)C(5)H(3)}(2)Th(NH-p-tolyl)(2)] (9), respectively. Diamides 7 and 9 do not eliminate methylamine or p-toluidine, but sublime without decomposition at 150 °C under vacuum (0.01 mmHg), whereas diamide 8 is converted at 140 °C/0.01 mmHg into the primary amine p-tolyl-NH(2) and [{?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th=N(p-tolyl)] (10), which may be isolated in pure form. Imido metallocene 10 does not react with electrophiles such as alkylsilyl halides; however, it reacts with electron-rich or unsaturated reagents. For example, reaction of 10 with sulfur affords the metallacycle [{?(5)-1,2,4-(Me(3)C)(3)C(5)H(2)}(2)Th{N(p-tolyl)S-S}]. Imido 10 is an important intermediate in the catalytic hydroamination of internal alkynes, and an efficient catalyst for the trimerization of PhCN. Density functional theory (DFT) studies provide a detailed understanding of the experimentally observed reactivity patterns.
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[Clinical significance of glycosylated serum protein in patients with diabetic nephropathy].
Nan Fang Yi Ke Da Xue Xue Bao
PUBLISHED: 06-22-2011
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To explore the relations between fasting blood glucose (FBG), glycosylated hemoglobin A1c (HbA1c) and glycosylated serum protein (GSP).
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Oral arginine improves linear growth of long bones and the neuroendocrine mechanism.
Neurosci Bull
PUBLISHED: 05-27-2011
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To investigate the effect of oral administration of arginine on linear growth of long bones in male pubertal rats and the underlying mechanisms, focusing on expression of genes related to the hypothalamus-pituitary growth axis and the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway.
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Perifosine as potential anti-cancer agent inhibits proliferation, migration, and tube formation of human umbilical vein endothelial cells.
Mol. Cell. Biochem.
PUBLISHED: 05-03-2011
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Targeting angiogenesis is considered an effective strategy for treating the expansion and metastasis of tumors. The aim of this study is to assess the effects of perifosine, an inhibitor of Akt, on cell proliferation, apoptosis, angiogenesis, and VEGF-induced cell migration in cultured human umbilical vein endothelial cells (HUVECs) in vitro. MTT and cell cycle analysis results indicated that perifosine inhibited the growth of HUVECs in a dose-dependent manner, arrested cell cycle progression at the G(2) phase with regulation the expression of p21 and cyclinB1. Apoptosis induced by the higher concentrations of perifosine in HUVECs was also observed. In addition, tube formation of HUVECs and VEGF-induced cell migration were markedly inhibited by perifosine. Western blotting analysis of cell signaling molecules indicated that perifosine inhibited ERK and p38 phosphorylation in HUVECs. These results suggest that perifosine exerts anti-angiogenic activity in HUVECs and is a promising agent for treatment of angiogenesis related-diseases.
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[Relations between serum adipocyte fatty acid-binding protein and type 2 diabetes in a community population].
Nan Fang Yi Ke Da Xue Xue Bao
PUBLISHED: 03-23-2011
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To study the relationship between the serum levels of adipocyte fatty acid-binding protein (A-FABP) level and type 2 diabetes mellitus in a community population.
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Circulating MicroRNAs: Potential Biomarkers for Cancer.
Int J Mol Sci
PUBLISHED: 02-10-2011
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Cancer is the leading cause of death in the world. Development of minimally invasive biomarkers for early detection of cancer is urgently needed to reduce high morbidity and mortality associated with malignancy. MicroRNAs (miRNAs) are small regulatory RNAs that modulate the activity of specific mRNA targets and play important roles in a wide range of physiologic and pathologic processes. Recently, miRNAs were found to be dysregulated in a variety of diseases including cancer. Emerging evidence suggests that miRNAs are involved in tumor initiation and progression. Together, the different expression profiles of miRNAs in cancer, and the stability of circulating miRNAs, make them new potentially clinical biomarkers for cancer diagnosis, classification, therapeutic decisions, and prognosis.
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Clinical studies on event-related potentials (ERPs) N400 and the related factors in patients with poststroke depression (PSD).
Int J Psychiatry Med
PUBLISHED: 12-21-2010
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To evaluate event-related potentials (ERPs), N400, and the related factors in patients with poststroke depression (PSD).
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Biodegradation of di-n-butyl phthalate by Rhodococcus sp. JDC-11 and molecular detection of 3, 4-phthalate dioxygenase gene.
J. Microbiol. Biotechnol.
PUBLISHED: 10-30-2010
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Rhodococcus sp. JDC-11, capable of utilizing di-n-butyl phthalate (DBP) as the sole source of carbon and energy, was isolated from sewage sludge and confirmed mainly based on 16S rRNA gene sequence analysis. The optimum pH, temperature, and agitation rate for DBP degradation by Rhodococcus sp. JDC-11 was 8.0, 30 degrees C, and 175 rpm, respectively. In addition, the effect of glucose concentration on DBP degradation indicated that low concentration of glucose inhibited the degradation of DBP while high concentrations of glucose increased its degradation. Meanwhile, the substrates utilization test showed that JDC-11 could also utilize other phthalates. Furthermore, the major metabolites of DBP degradation were identified as mono-butyl phthalate and phthalic acid by gas chromatography-mass spectrometry and the metabolic pathway of DBP degradation by Rhodococcus sp. JDC-11 was tentatively speculated. Using a set of new degenerate primer, partial sequence of the 3, 4-phthalate dioxygenase gene was obtained from the strain. Sequence analysis revealed that the phthalate dioxygenase gene of JDC-11 was highly homologous to the large subunit of phthalate dioxygenase from Rhodococcus coprophilus strain G9.
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