53 research outputs found
DNA Methylation in hypoxia in Mycobacterium tuberculosis
Tuberculosis is one of the most lethal contagious diseases caused by
Mycobacterium tuberculosis (MTB), in many cases, the infected did not show any
symptoms, because the bacilli entered the dormant stage in granulomas. The
dormant stage of MTB is also associated with higher resistance to drugs and the
immune system. Among multiple epigenetic regulations critical to MTB stress
responses, DNA methylation is necessary for the survival of MTB in hypoxic
conditions, which is a common stress event during granuloma formation. This
review gathers previous findings and demonstrates a meta-analysis by collecting
hypoxia gene expression data from several articles and perform association
analysis between those genes and methylation site profiles across whole genomes
of representative strains pf lineage 2 and 4. While more data is required for
more conclusive support, our results suggest that methylation sites in the
possible promoter regions may induce differential gene regulation in hypoxia.Comment: 20 pages, 9 table
Precipitation hardening and structure evolution in hypereutectic Al-6% Fe-Zr alloys subjected to ultrasonic melt processing
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Synergetic grain refinement and ZrB2 hardening in in-situ ZrB2/AA4032-type composites by ultrasonic assisted melt treatment
Copyright © 2023 The Author(s). In this work, the effects of ultrasonic treatment on in-situ ZrB2 particle-reinforced AA4032-based composites were studied. The composites were synthesized from Al–K2ZrF6–KBF4 system via an in-situ melt reaction. The phase composition, macrostructure characteristics, hardness and tensile properties of the composites were investigated. The results showed that the addition of in-situ submicron ZrB2 particles into the composites resulted in grain refinement, and the increased hardness and tensile properties. The ultrasonic treatment effectively enhanced the uniformity of in-situ ZrB2 distribution, which further enhanced the structure and mechanical properties of the composites. The mechanisms of the ultrasonic treatment in the improvement of in-situ particle distribution and mechanical properties of the composites were discussed.Research Strengthening Project of the Faculty of Engineering, King Mongkut's University of Technology Thonburi. SC acknowledges the financial support from King Mongkut's Institute of Technology Ladkrabang (2564-02-01-007)
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Precipitation hardening and structure evolution in hypereutectic Al-6 % Fe-Zr alloys subjected to ultrasonic melt processing
Data availability: Data will be made available on request.Supplementary material is available online at: https://www.sciencedirect.com/science/article/pii/S0925838823039166#sec0075 .Copyright © 2023 The Author(s). The objective of this research was to study the influence of Zr concentration and ultrasonic melt processing (USP) on the microstructure and precipitation hardening of a hypereutectic Al-6% Fe alloy. Such alloys have a good potential in high-temperature, wear-resistant, and conducting applications but suffer from coarse structure and low strength/ductility, which prevents their processing. The microstructure of the studied alloys consisted of primary Al13Fe4 intermetallics and (Al)+Al13Fe4 eutectic colonies, which were successfully refined by adding Zr and performing USP. The mechanisms of USP and Zr were confirmed for the Al-6 % Fe alloys with a range of Zr additions. The structure refinement led to improved hardness and tensile properties of the alloys. All studied alloys demonstrated strong precipitation hardening effect with hardness increasing 4–5 times, reaching 170 HV for the alloy with 0.4 % Zr after annealing at 400 ℃ for 20 hrs. The electrical conductivity increased from 25 % IACS in the as-cast alloy to 40% IACS in the annealed Al-6% Fe-0.4 % Zr alloy. The prime novelty of this work is a considerable increase of hardness upon annealing, i.e. more than 100 HV, in the Al-6 % Fe alloy with only minute traces of Zr (<0.01 %). The precipitation phenomena were investigated by transmission electron microscopy. The precipitation of the semi-coherent Al13Fe4 phase with Zr segregated to its surface was observed for the first time. All studied alloys (with minute and larger Zr additions) showed the precipitation of this phase, while the alloys with the larger amount of Zr also demonstrated the precipitation of the metastable L12 Al3Zr phase. Therefore, the properties improvement was attributed to the structure refinement and the formation of Zr-modified Al13Fe4 and Al3Zr precipitates in the microstructure.The authors gratefully acknowledge FE-SEM Center, School of Engineering, King Mongkut’s Institute of Technology Ladkrabang and the financial support under project number KREF046409. D.E. acknowledges the financial support from EPSRC (UK) under the project grant PAAM (EP/W00593X/1). S.C. gratefully acknowledges BCAST (UK) for the use of TEM sample preparation facilities. P.P. and C.L. acknowledge the financial support from Thailand Science Research and Innovation (TSRI), through Fundamental Fund 2023 (Project: Advanced Materials and Manufacturing for Applications in New S-curve Industries) and the Research Strengthening Project (year 2563) by Faculty of Engineering, KMUTT
Personal Wellbeing Index in a National Cohort of 87,134 Thai Adults
Satisfaction with life correlates with other measures of subjective wellbeing and correlates predictably with individual characteristics and overall health. Social indicators and subjective wellbeing measures are necessary to evaluate a society and can be used to produce national indicators of happiness. This study therefore aims to help close the gap in wellbeing data for Thailand. The specific aims are to: (1) calculate the Thai PWI and domain scores using a large scale sample; (2) examine the level of life satisfaction of Thais when compared to international standards; (3) examine the Thai PWI and domains in relation to demographic, socioeconomic, and geographic characteristics. Our report derives from the findings on the Personal Wellbeing Index (PWI) in a large national cohort of Sukhothai Thammathirat Open University adult students living all over Thailand (n = 87,134). This Thai cohort had an overall PWI of 70.0 on a scale from 0 to 100 which is consistent with Western populations. The ‘spirituality and religion’ domain had the highest average score. ‘Standard of living’, ‘future security’ and ‘achievement in life’ made the largest contribution to overall ‘satisfaction in life as a whole’. These domains also show a positive trend with increasing age, being married, higher income, more education, more household assets, and rural residence. The PWI will be an important tool for policymakers to understand the subjective wellbeing of population groups especially as Thailand is undergoing a political and economic transition
Short sleep and obesity in a large national cohort of Thai adults
Objective: To investigate the relationship between short sleep and obesity among Thai adults
Oral Health-Related Quality of Life among a large national cohort of 87,134 Thai adults
Background Oral health has been of interest in many low and middle income countries due to its impact on general health and quality of life. But there are very few population-based reports of adult Oral Health Related Quality of Life (OHRQoL) in developing countries. To address this knowledge gap for Thailand, we report oral health findings from a national cohort of 87,134 Thai adults aged between 15 and 87 years and residing all over the country. Methods In 2005, a comprehensive health questionnaire was returned by distance learning cohort members recruited through Sukhothai Thammathirat Open University. OHRQoL dimensions included were discomfort speaking, swallowing, chewing, social interaction and pain. We calculated multivariate (adjusted) associations between OHRQoL outcomes, and sociodemographic, health behaviour and dental status. Results Overall, discomfort chewing (15.8%), social interaction (12.5%), and pain (10.6%) were the most commonly reported problems. Females were worse off for chewing, social interaction and pain. Smokers had worse OHRQoL in all dimensions with Odds Ratios (OR) ranging from 1.32 to 1.51. Having less than 20 teeth was strongly associated with difficulty speaking (OR = 6.43), difficulty swallowing (OR = 6.27), and difficulty chewing (OR = 3.26). Conclusions Self-reported adverse oral health correlates with individual function and quality of life. Outcomes are generally worse among females, the poor, smokers, drinkers and those who have less than 20 teeth. Further longitudinal study of the cohort analysed here will permit assessment of causal determinants of poor oral health and the efficacy of preventive programs in Thailand
Screening, production and biochemical characterization of a new fibrinolytic enzyme produced by Streptomyces sp. (Streptomycetaceae) isolated from Amazonian lichens
Thrombosis is a pathophysiological disorder caused by accumulation of fibrin in the blood. Fibrinolytic proteases with potent thrombolytic activity have been produced by diverse microbial sources. Considering the microbial biodiversity of the Amazon region, this study aimed at the screening, production and biochemical characterization of a fibrinolytic enzyme produced by Streptomyces sp. isolated from Amazonian lichens. The strain Streptomyces DPUA1576 showed the highest fibrinolytic activity, which was 283 mm2. Three variables at two levels were used to assess their effects on the fibrinolytic production. The parameters studied were agitation (0.28 - 1.12 g), temperature (28 - 36 ºC) and pH (6.0 - 8.0); all of them had significant effects on the fibrinolytic production. The maximum fibrinolytic activity (304 mm2) was observed at 1.12 g, 28 ºC, and pH of 8.0. The crude extract of the fermentation broth was used to assess the biochemical properties of the enzyme. Protease and fibrinolytic activities were stable during 6 h, at a pH ranging from 6.8 to 8.4 and 5.8 to 9.2, respectively. Optimum temperature for protease activity ranged between 35 and 55 °C, while the highest fibrinolytic activity was observed at 45 ºC. Proteolytic activity was inhibited by Cu2+ and Co2+ ions, phenylmethylsulfonyl fluoride (PMSF) and pepstatin A, which suggests that the enzyme is a serine protease. Enzymatic extract cleaved fibrinogen at the subunits A-chain, A-chain, and -chain. The results indicated that Streptomyces sp. DPUA 1576 produces enzymes with fibrinolytic and fibrinogenolytic activity, enzymes with an important application in the pharmaceutical industry.The authors grateful acknowledge the financial support of Fundação de Amparo a Pesquisa do Estado de Pernambuco (FACEPE, Pernambuco, Brazil, N. 0158-2.12/11), CNPq/ RENORBIO (National Counsel of Technological and Scientific Development, N.55146/2010-3) and National Council for the Improvement of Higher Education (CAPES, Brazil) for the scholarship. The author thanks editor and reviewers for their review and comments.info:eu-repo/semantics/publishedVersio
Long-term air pollution exposure and self-reported morbidity: A longitudinal analysis from the Thai cohort study (TCS)
[Background] Several studies have shown the health effects of air pollutants, especially in China, North American and Western European countries. But longitudinal cohort studies focused on health effects of long-term air pollution exposure are still limited in Southeast Asian countries where sources of air pollution, weather conditions, and demographic characteristics are different. The present study examined the association between long-term exposure to air pollution and self-reported morbidities in participants of the Thai cohort study (TCS) in Bangkok metropolitan region (BMR), Thailand. [Methods] This longitudinal cohort study was conducted for 9 years from 2005 to 2013. Self-reported morbidities in this study included high blood pressure, high blood cholesterol, and diabetes. Air pollution data were obtained from the Thai government Pollution Control Department (PCD). Particles with diameters ≤10 μm (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), and carbon monoxide (CO) exposures were estimated with ordinary kriging method using 22 background and 7 traffic monitoring stations in BMR during 2005–2013. Long-term exposure periods to air pollution for each subject was averaged as the same period of person-time. Cox proportional hazards models were used to examine the association between long-term air pollution exposure with self-reported high blood pressure, high blood cholesterol, diabetes. Results of self-reported morbidity were presented as hazard ratios (HRs) per interquartile range (IQR) increase in PM₁₀, O₃, NO₂, SO₂, and CO. [Results] After controlling for potential confounders, we found that an IQR increase in PM₁₀ was significantly associated with self-reported high blood pressure (HR = 1.13, 95% CI: 1.04, 1.23) and high blood cholesterol (HR = 1.07, 95%CI: 1.02, 1.12), but not with diabetes (HR = 1.05, 95%CI: 0.91, 1.21). SO₂ was also positively associated with self-reported high blood pressure (HR = 1.22, 95%CI: 1.08, 1.38), high blood cholesterol (HR = 1.20, 95%CI: 1.11, 1.30), and diabetes (HR = 1.21, 95%CI: 0.92, 1.60). Moreover, we observed a positive association between CO and self-reported high blood pressure (HR = 1.07, 95%CI: 1.00, 1.15), but not for other diseases. However, self-reported morbidities were not associated with O₃ and NO₂. [Conclusions] Long-term exposure to air pollution, especially for PM₁₀ and SO₂ was associated with self-reported high blood pressure, high blood cholesterol, and diabetes in subjects of TCS. Our study supports that exposure to air pollution increases cardiovascular disease risk factors for younger population
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