Origin and Accumulation Mechanism of Gas Condensate in Kailashtila Gas Field, Sylhet Basin, Bangladesh

The Kailashtila gas field (KGF) is situated in the northeastern part of Sylhet basin, Bangladesh. This paperpresents chemical characteristics of extractable natural gas in drilled well KTL-2, in order to examine their potentialsource and maturity of organic matter, and hydrocarbon accumulation mechanism in the basin. The gas condensate inthe KTL-2 composed primarily of methane (85.81 wt.%), ethane (6.68 wt.%), propane (2.13 wt.%), and traces of higherhydrocarbons (i-butane, 0.69 wt.%; n-butane, 0.73 wt.%; i-pentane, 0.50 wt.%; n-pentane, 0.44 wt.%; hexane, 1.27wt.%; heptane, 0.99 wt.%; octane, 0.24 wt.%). Nitrogen and CO2 contents in the gas condensate are low (0.46 wt.%and 0.05 wt.%, respectively). Average dry coefficient (C1/C1–5) value in the gas condensate is 0.93 (0.91–0.95), whichreflects relatively mature hydrocarbon migrating from nearby deeply buried source rocks. The δ13C1 (–39 to –40‰) andC1/C(2+3) (19.77) variation diagram show that gas condensate in the KGF is mainly controlled by type III kerogen, andthe organic matter was thermally mature in nature. However, the relationships between stable isotope value of methane(δ13C1), ethane (δ13C2) and propane (δ13C3) indicate mainly thermogenic origin of the studied gas condensate, andminor input from mixed thermogenic and bacteriogenic processes

Thermal, chemical and morphological properties of carbon fibres derived from chemically pre-treated wool fibres

In this work, the feasibility of using wool fibre as a carbon fibre precursor was explored as well as whether chemical treatments to wool fibre can increase the carbon fibre yield and properties of the produced carbon fibres. Wool fibres were treated with a range of chemicals including lignin, tannic acid, polystyrene sulphonate, and chlorine in conjunction with a polyamide resin. The treated fibres were stabilised in air at 160 C followed by pyrolysis at 800 C under a nitrogen atmosphere. The resulting carbon fibres were characterised in terms of carbon yield, tensile strength, surface roughness, porosity, crystal structure and surface hydrophobicity. The carbon fibre yield was 16.7% for the untreated while the lignin pre-treatment increased the carbon yield up to 25.8%. Generally the surface of the carbon fibre made from both untreated and treated fibre exhibited high hydrophilicity except the lignin and chlorine/polyamide resintreated fibre which showed hydrophobicity. Although the tensile strength achieved for the various produced carbon fibre was poor compared to a commercially available pitch-based carbon fibre, the developed carbon fibre still can be utilised in thermoplastic composite manufacturing

Securing superior properties of composite (PP+WF) through central composite design

Due to numerous attractive properties, use of composites is in increasing trend. Efforts are being made to develop new composites securing their useful properties at optimum level for more demanding applications. The purpose of this project is to optimize the mechanical properties of composite (polypropylene + wood fiber) using Central Composite Design (CCD) technique. Accordingly experiments were conducted to develop mathematical models in terms of three process parameters - composition (percentage of PP and wood fiber), injection pressure (bar), and time (second) for functional characteristics such as tensile strength and water absorption. Design expert software was used for convenience to carry out the analysis with a view to identifying the optimum level of the processing parameters for securing the desirable properties of the composite

Age-related Risk Factors and Severity of SARS-CoV-2 Infection: a systematic review and meta-analysis

Objectives: We aimed to estimate the reported symptoms and comorbidities and assess the correlation between a series of symptoms and comorbidities and age of the patients’ positive in COVID-19. Methods: We performed a systematic review and meta-analysis [PROSPERO registration: CRD42020182677]. Databases [PubMed, SCOPUS, EMBASE, WHO, Semantic Scholar, and COVID-19 Primer] were searched for clinical studies published from January to April 2020. The pooled prevalence of symptoms and comorbidities were identified using the random effect model, and the multivariable factor analysis was performed to show the correlation between a group of symptoms and comorbidities and age of the COVID-19 patients. Results: Twenty-nine articles, with 4,884 COVID-19 patients were included in this study.  Altogether, we found 33 symptoms and 44 comorbidities where the most frequent 19 symptoms and 11 comorbidities were included in the meta-analysis. The fever [84%], cough/dry cough [61%], and fatigue/weakness [42%] were found more prevalent. On the other hand, acute respiratory distress syndrome, hypertension and diabetes were the most prevalent comorbid condition. The multivariable factor analysis showed positive association between a group of symptoms and comorbidities, and with the patients' age. The symptoms comprising fever, dyspnea/shortness of breath, nausea, vomiting, abdominal pain, dizziness, anorexia and pharyngalgia; and the comorbidities including diabetes, hypertension, coronary heart disease, COPD/lung disease and ARDS were positively correlated with the COVID-19 patient’s age. Conclusion: As a unique effort, this study found a group of symptoms and comorbidities, correlated with age of the COVID-19 patients that may help to implement patient-centred interventions

Nonmalignant Respiratory Effects of Chronic Arsenic Exposure from Drinking Water among Never-Smokers in Bangladesh

BACKGROUND: Arsenic from drinking water has been associated with malignant and nonmalignant respiratory illnesses. The association with nonmalignant respiratory illnesses has not been well established because the assessments of respiratory symptoms may be influenced by recall bias or interviewer bias because participants had visible skin lesions. OBJECTIVES: We examined the relationship of the serum level of Clara cell protein CC 16-a novel biomarker for respiratory illnesses-with well As, total urinary As, and urinary As methylation indices. METHODS: We conducted a cross-sectional study in nonsmoking individuals (n = 241) selected from a large cohort with a wide range of As exposure (0.1-761 mu g/L) from drinking water in Bangladesh. Total urinary As, urinary As metabolites, and serum CC16 were measured in urine and serum samples collected at baseline of the parent cohort study. RESULTS: We observed an inverse association between urinary As and serum CC 16 among persons with skin lesions (beta = -0. 13, p = 0.01). We also observed a positive association between secondary methylation index in urinary As and CC16 levels (beta = 0. 12,,P = 0.05) in the overall study population; the association was stronger among people without skin lesions (beta = 0. 18, p = 0.04), indicating that increased methylation capability may be protective against As-induced respiratory damage. In a subsample of study participants undergoing spirometric measures (n = 3 1), we observed inverse associations between urinary As and predictive FEV1 (forced expiratory volume measured in 1 sec) (r = -0.37; FEV1/forced vital capacity ratio and primary methylation index (r = -0.42, p = 0.01). CONCLUSIONS: The findings suggest that serum CC 16 may be a useful biomarker of epithelial lung damage in individuals with arsenical skin lesions. Also, we observed the deleterious respiratory effects of As exposure at concentrations lower than reported in earlier studies

Characterization techniques for studying the properties of nanocarriers for systemic delivery

Nanocarriers have attracted a huge interest in the last decade as efficient drug delivery systems and diagnostic tools. They enable effective, targeted, controlled delivery of therapeutic molecules while lowering the side effects caused during the treatment. The physicochemical properties of nanoparticles determine their in vivo pharmacokinetics, biodistribution and tolerability. The most analyzed among these physicochemical properties are shape, size, surface charge and porosity and several techniques have been used to characterize these specific properties. These different techniques assess the particles under varying conditions, such as physical state, solvents etc. and as such probe, in addition to the particles themselves, artifacts due to sample preparation or environment during measurement. Here, we discuss the different methods to precisely evaluate these properties, including their advantages or disadvantages. In several cases, there are physical properties that can be evaluated by more than one technique. Different strengths and limitations of each technique complicate the choice of the most suitable method, while often a combinatorial characterization approach is needed

Enhanced corrosion inhibition of mild steel by cross-linked lanolin-coatings

Mild steel exhibits moderate to poor corrosion resistance in some service conditions. In this work, several corrosion inhibiting formulations were prepared by mixing three different grades of commercially available linseed oils, namely crude, drying and refined, to lanolin (wool grease). Mild steel plates were coated with those formulations and their corrosion inhibition performance was assessed by various methods. We found that the addition of linseed oils to lanolin considerably increased corrosion inhibition performance of the lanolin-coated steel plates. Of the linseed oils investigated, lanolin containing 15% drying linseed oil (DLO)-coated plates showed the best corrosion inhibition, the lowest weight loss and the lowest surface tackiness. Fourier transform infra-red (FT-IR) analysis and the increased contact angle for the DLO-containing lanolin-coated plates suggest that DLO formed crosslink with lanolin

Formation of three new flavones by differentiating callus cultures of <i>Andrographis paniculata</i>

Differentiating tissue cultures of Andrographis paniculata produce three new flavones, 5-hydroxy-7,8,2′-trimethoxy-, 5,2′-dihydroxy-7,8-dimethoxy- and 5-hydroxy-7,8-dimethoxy-flavones. Flavones are not synthesized by the de-differentiated callus. Closely related flavones have been isolated from intact plants of Andrographis species