Browsing by Author "Li, W."
Now showing 1 - 8 of 8
Results Per Page
Sort Options
Item A contribution to common Carius tube distillation techniques(Journal of Analytical Atomic Spectrometry, 2013-02) Jin, X.; Li, W.; Xiang, P.; Sakyi, P.A.; Zhu, M.; Zhang, L.In this paper, we introduce an economic electrothermal timing steamer for common Carius tube Os in situ distillation. It is suitable for analysing several batches of samples. Its configuration allows the Carius tubes to be properly fixed and bathed in steam into which the tubes are immersed. The top of each Carius tube is sealed with a stretchy rubber head through which a pair of teflon tubes pierce, serving as inlet and outlet for clean air and OsO4 respectively. At steam temperatures of 99-100 °C, OsO4 in the sample solutions inside the Carius tubes is evaporated out and subsequently carried by clean air to the trapping water in an ampoule bottle, immersed in a box filled with ice. In the present study the steamer allowed for the convenient, efficient and simultaneous distillation of Os from seven samples with near ninety percent recovery. The blank values were 0.42 ± 0.15 pg and 0.26 ± 0.05 for 187Os and 187Os/ 188Os (n = 4). The dating results of reference materials (RMs) namely Henderson, HLP and JDC were in accordance with reference and certified values within the range of uncertainties. The special steamer has successfully been used in the analysis of pyrite samples for the distillation of Os. © 2013 The Royal Society of Chemistry.Item Early Mesozoic tectono-magmatic activity and mineralization in northeast China: Evidence from Re-Os to U-Pb studies of the Taipingchuan porphyry Cu-Mo deposit in the Derbugan metallogenic belt(International Geology Review, 2014-10) Zhang, L.; Gao, B.; Li, W.; Chen, Z.; Sakyi, P.A.; Jin, X.The Taipingchuan Cu-Mo deposit is a recently discovered large porphyry deposit located in the north of the Derbugan metallogenic belt of northeastern China. The geochronological data of the deposit yielded a Late Triassic zircon U-Pb age of 202 ± 6 Ma from a granodiorite porphyry that hosts the Cu-Mo mineralization. Measured Re-Os isotopes of seven disseminated molybdenite samples yielded an isochron age of 200 ± 5 Ma with mean square of weighted deviates of 2.7, while those of seven veinlet molybdenite samples also produced an isochron age of 200.1 ± 2.5 Ma and mean square of weighted deviates of 3.3. These isochron ages show that a Cu-Mo mineralization event occurred at ca. 200 Ma. Based on regional tectonic evolution, we propose that the Late Triassic Cu-Mo mineralization of the host porphyry in the Derbugan metallogenic belt was mainly associated with the subduction of the Mongol-Okhotsk Ocean slab under the Ergun block, contrary to previous suggestion that it was related to the subduction of the Mesozoic Palaeo-Pacific plate. © 2014 Taylor & Francis.Item Impact of MBL and MASP-2 gene polymorphism and its interaction on susceptibility to tuberculosis(BMC Infectious Diseases, 2015-03) Chen, M.; Liang, Y.; Li, W.; Wang, M.; Hu, L.; Abuaku, B.K.; Huang, X.; Tan, H.; Wen, S.W.Background Mannose-binding lectin (MBL) and MBL-associated serine proteases 2 (MASP-2) are important proteins in the lectin pathway of the immune system. Polymorphism of MBL and MASP-2 genes may affect the serum concentration of MBL and MASP-2. This study explores the association between MBL and MASP-2 gene polymorphism and their interactions and the susceptibility to tuberculosis (TB). Method A total of 503 patients with TB and 419 healthy controls were recruited to participate in this case-control study. PCR-SSP technology was applied to genotype rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes. Demographic data and some exposure information were also obtained from study participants. Unconditional logistic regression analysis was used to identify association between the various factors and TB whilst Marginal Structural Linear Odds Models were used to estimate the interactions. Results Both genotype GC at rs7096206 of MBL genes and genotype TC at rs2273346 and rs6695096 of MASP-2 genes were more prevalent in the TB patient group than the healthy control group (P < 0.05, OR 1.393, 1.302 and 1.426 respectively). The relative excess risk of interaction (RERI) between rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes was 0.897 (95% CI: 0.282, 1.513) and 1.142 (95% CI: 0.755, 1.530) respectively (P < 0.05). Conclusion Polymorphisms of MBL (rs7096206) and MASP-2 (rs2273346 and rs6695096) were associated with the susceptibility of TB, and there were gene-gene interactions among them. (PDF) Impact of MBL and MASP-2 gene polymorphism and its interaction on susceptibility to tuberculosis. Available from: https://www.researchgate.net/publication/275065858_Impact_of_MBL_and_MASP-2_gene_polymorphism_and_its_interaction_on_susceptibility_to_tuberculosis [accessed Oct 22 2018].Item Impact of MBL and MASP-2 gene polymorphism and its interaction on susceptibility to tuberculosis(BioMed Central Ltd., 2015) Chen, M.; Liang, Y.; Li, W.; Wang, M.; Hu, L.; Abuaku, B.K.; Huang, X.; Tan, H.; Wen, S.W.Background: Mannose-binding lectin (MBL) and MBL-associated serine proteases 2 (MASP-2) are important proteins in the lectin pathway of the immune system. Polymorphism of MBL and MASP-2 genes may affect the serum concentration of MBL and MASP-2. This study explores the association between MBL and MASP-2 gene polymorphism and their interactions and the susceptibility to tuberculosis (TB). Method: A total of 503 patients with TB and 419 healthy controls were recruited to participate in this case-control study. PCR-SSP technology was applied to genotype rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes. Demographic data and some exposure information were also obtained from study participants. Unconditional logistic regression analysis was used to identify association between the various factors and TB whilst Marginal Structural Linear Odds Models were used to estimate the interactions. Results: Both genotype GC at rs7096206 of MBL genes and genotype TC at rs2273346 and rs6695096 of MASP-2 genes were more prevalent in the TB patient group than the healthy control group (P < 0.05, OR 1.393, 1.302 and 1.426 respectively). The relative excess risk of interaction (RERI) between rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes was 0.897 (95% CI: 0.282, 1.513) and 1.142 (95% CI: 0.755, 1.530) respectively (P < 0.05). Conclusion: Polymorphisms of MBL (rs7096206) and MASP-2 (rs2273346 and rs6695096) were associated with the susceptibility of TB, and there were gene-gene interactions among them.Item Impact of tea drinking upon tuberculosis: A neglected issue(BioMed Central Ltd., 2015) Chen, M.; Deng, J.; Li, W.; Lin, D.; Su, C.; Wang, M.; Li, X.; Abuaku, B.K.; Tan, H.; Wen, S.W.Background: Tuberculosis (TB) is a global public health issue posing serious harm to the human health. Many studies have suggested that smoking and excessive alcohol consumption are risk factors for TB. Laboratory evidence suggests that EGCG in tea leaves can arrest the growth of tubercle bacillus. Can drinking tea lead to decreased susceptibility of TB in humans? Methods: A total of 574 TB patients and 582 healthy controls were recruited to participate in this case-control study. Self-designed questionnaire was used to collect data. Unconditioned logistic regression analysis was conducted to identify the associations between tea drinking and TB. Results: Tea drinking has a negative association with TB, with OR∈=∈0.583(0.423, 0.804) and P∈<∈0.05. Drinking black tea, oolong and green tea are all negative association with TB, with OR being 0.683(0.517, 0.902), 0.674(0.508, 0.894) and 0.534(0.349, 0.817) respectively and P∈<∈0.05. Trend χ 2 test indicated a decreasing risk for TB with increased tea consumption, with P∈<∈0.05. Conclusion: There is a significance negative association between tea drinking and TB. Promoting the consumption of tea as the daily drink among populations, particularly those with high TB risk, may reduce the incidence of TB in the populations. © 2015 Chen et al.; licensee BioMed Central.Item LLHR-type chalcopyrite Re-Os geochronology and geochemistry of the Xiaotongchang Cu deposit in south Ailaoshan and its geological significances(Journal of Geochemical Exploration, 2019-03) Li, W.; Gao, B.; Zhang, L.; Jin, X.; Sakyi, P.A.The Xiaotongchang Cu deposit is located in the south Ailaoshan and at the contact between Yunnan province of China and Vietnam. Four Cu ore bodies are distributed parallel to each other in an interlayer fracture zone in the Permian Emeishan basalt. The major ore mineral in the deposit is chalcopyrite, and the main gangue minerals are quartz and calcite. New Re-Os data for chalcopyrite from the Xiaotongchang Cu deposit show tens of ppb Re abundances (1–86 ppb) and contain essentially no common Os. All the samples have extremely high 187Re/188Os (up to 2.3 × 104), and the dominance of radiogenic Os and high 187Re/188Os are diagnostic features of “LLHR” (low-level, highly radiogenic) sulfides. The Re-Os isochrone age for the No. 1 and No. 3 Cu bodies show that the phase of Cu mineralization predominantly occurred in the Middle Triassic, with an age of 230.6 ± 1.1 Ma. Thus, the mineralization occurred much later than the periods of major eruption of the Emeishan large igneous provinces, indicating a closer relationship with the late collisional processes in the Ailaoshan orogenic belt. Combined with REEs patterns and consistently positive δ34S values (7.4–9.2‰), it can be concluded that the ore-forming materials of the Cu deposit are derived from a mixture of mantle and crust components.Item A new modification of the sample introduction system for Os isotope ratio measurements(Journal of Analytical Atomic Spectrometry, 2011-06) Jin, X.; Du, A.; Li, W.; Xiang, P.; Sakyi, P.A.; Zhang, L.Here we present a new modification of the sample introduction system aimed at precisely measuring Os isotope ratios. A small glass connector was used to transfer OsO4 vapor from a Carius tube into a nebulizer. After dissolution of sample in a Carius tube, Os isotopes in the sample were determined simultaneously through in situ distillation without any prior separation procedure. The analytical precision at intermediate precision conditions of measurement was improved through the simultaneous introduction of Os via sparging and the aspiration of a solution containing Ir for mass bias correction. The present method, which involves the passage of Os vapor directly into the ICP-MS torch, thus solves the problems encountered previously when optimizing an instrument. The dating results of reference materials (RMs) HLP and JDC by the modified method are 221.8 ± 0.70 Ma (0.31%, 2s, n = 7) and 140.0 ± 0.44 Ma (0.31%, 2s, n = 9) respectively, which are consistent with their certified values of 221.4 ± 5.6 Ma and 139.6 ± 3.8 Ma respectively. Also reported in this study are dating results of several unknown molybdenite samples by the new method. © 2011 The Royal Society of Chemistry.Item The relationship between chitotriosidase activity and tuberculosis(Epidemiology and Infection, 2015-04) Chen, M.; Deng, J.; Li, W.; Su, C.; Xia, Y.; Wang, M.; Li, X.; Abuaku, B.K.; Tan, H.; Wen, S.W.Chitotriosidase, secreted by activated macrophages, is a biomarker of activated macrophages. In this study, we explored whether chitotriosidase could be adopted as a biomarker to evaluate the curative effect on tuberculosis (TB). Five counties were randomly selected out of 122 counties/cities/districts in Hunan Province, China. Our cases were all TB patients who were newly diagnosed or had been receiving treatment at the Centers for Disease Control (CDCs) of these five counties between April and August in 2009. Healthy controls were selected from a community health facility in the Kaifu district of Changsha City after frequency-matching of gender and age with the cases. Chitotriosidase activity was evaluated by a fluorometric assay. Categorical variables were analysed with the χ 2 test. Measurement data in multiple groups were tested with analysis of variance and least significant difference (LSD). Correlation between chitotriosidase activity and the degree of radiological extent (DRE) was examined by Spearman's rank correlation test. The average chitotriosidase activity levels of new TB cases, TB cases with different periods of treatment (<3, 3-6, >6 months) and the control group were 54·47, 34·77, 21·54, 12·73 and 10·53 nmol/h.ml, respectively. Chitotriosidase activity in TB patients declined along with the continuity of treatment. The chitotriosidase activity of both smear-positive and the smear-negative pulmonary TB patients decreased after 6 months' treatment to normal levels (P < 0·05). Moreover, chitotriosidase activity was positively correlated with DRE (r = 0·607, P < 0·001). Our results indicate that chitotriosidase might be a marker of TB treatment effects. However, further follow-up study of TB patients is needed in the future. Copyright © Cambridge University Press 2015.