19672 research outputs found
Sort by
Immunogenic and antigenic heterogeneity of blastocystis sp. Subtype 3 from symptomatic and asymptomatic individuals
No full textBlastocystis sp. subtype 3 (ST3) has been implicated previously to be phenotypically heterogeneous between isolates from symptomatic and asymptomatic persons in previous studies. The aim of this study is to identify the immunogenic and antigenic heterogeneity among three different isolates of Blastocystis sp. ST3 isolated from asymptomatic and symptomatic individuals. Immunogenic and antigenic profile of ST3 isolates was assessed through splenocyte proliferation, cytokine assessment and antibody measurements. The total IgG antibody responses in mice immunised with symptomatic (0.736±0.033) and asymptomatic (0.426±0.025) of ST3 Blastocystis sp. were significantly higher compared to the controls respectively. High secretions of IgG antibody mixture of IgG1/IgG2a antibodies were detected in sera of mice immunised with symptomatic and asymptomatic solubilised Blastocystis sp. Antigen (Blastocystis-Ag). Predominant IgG1 production was detected higher in mice injected with Blastocystis sp. ST 3 from asymptomatic individuals (0.148±0.016) (P<0.05) whereas predominant IgG2a production was detected higher in mice injected with the same subtype but from the symptomatic individuals (0.355±0.021). This data was supported by the production of significantly higher Th1 (IFNγ and IL-2) response (393.56±49.21) and (628.89±31.06) respectively in symptomatic isolates compared to Th2 (IL-4 and IL-10) response (93±7.85) and (103.22±11.33) in asymptomatic isolates after in-vitro stimulations. Splenocyte stimulation index (SI) was detected higher in symptomatic Blastocystis-Ag group. This study is the first to demonstrate antigenic and immunogenic heterogeneity among ST3 symptomatic and asymptomatic Blastocystis-Ag with symptomatic isolates being highly immunogenic and antigenic. No significant variations among the three isolates of asymptomatic and symptomatic groups. The study supports the suggestion from previous study that surface variations between symptomatic and asymptomatic isolates as well their distinct phenotypic variation despite being the same subtype may have caused the differences in the distinct immune responses. © 2019, Malaysian Society for Parasitology. All rights reserved
Modelling and optimization of Searaser wave energy converter based hydroelectric power generation for Saint Martin's Island in Bangladesh
No full textSaint Martin's Island is one of the most notable tourist spots and the only coral island of Bangladesh in the Bay-of-Bengal. Yet due to lack of electricity supply, this beautiful island is becoming uninhabitable and losing tourist attraction. In this study, a decentralized Mini Hydroelectric Power Plant (MHPP) has been proposed and designed to mitigate electricity demand in the tourist resorts of the island during peak demand–hours: the energy input to the plant is supplied by harnessing ocean wave-power available in the coastal regions of the island with a novel and simple Wave Energy Converter (WEC) named Searaser. To decide about the installed capacity of the proposed MHPP, a field survey was conducted on the resorts of St. Martin's Island. The performance of Searaser in the context of the island was investigated theoretically which indicated that the Searaser is capable of producing about 35 m of water-head by utilizing the available wave-power. Realizing the availability of wave-power and adopting sustainable tourism policy, the estimated plant capacity was about 144 kW. This study remarks that the implementation of Searaser based MHPP technology in the St. Martin's Island can be a profitable and eco-friendly replacement of the existing stand-alone diesel-generators; it was also found that huge amount of Greenhouse Gas (GHG) emission can be prevented, and thereby the tourism potential can be enhanced as well. © 2019 Elsevier Lt
Polyaniline-SrTiO3 nanocube based binary nanocomposite as highly stable electrode material for high performance supercapaterry
No full textThe current study demonstrates the simplistic approach for the synthesis of SrTiO 3 nanocubes incorporated polyaniline flakes (PANI-SrTiO 3 ) by facile in-situ oxidative polymerisation route. The synthesised nanocomposites were characterised by various spectroscopic and surface analysis techniques viz. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Brunauer-Emmett-Teller analysis (BET). The electrochemical performance of the prepared nanocomposites for energy storage application was evaluated by electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge (GCD) and cyclic voltammetry (CV) in 1 M of KOH as an electrolyte. The electrochemical investigations demonstrate that the performance of the PANI-SrTiO 3 nanocomposite in terms of rate capability was significantly higher as compared to the polyaniline flakes and SrTiO 3 nanocubes. Supercapattery was fabricated by combining activated carbon and PANI-SrTiO 3 -250 as negative and positive electrodes respectively in order to evaluate complete device performance. It is found that fabricated supercapattery gave an energy density of 13.2 W h/kg at a power density of 299 W/kg. Additionally, the fabricated supercapattery also offered excellent stability cycle with 114% capacity retention after 4000 cycles. Moreover, the performance of PANI-SrTiO 3 -250 was found to be better than the other compositions. © 201
Cynometra cauliflora Linn. Attenuates metabolic abnormalities in high-fat diet-induced obese mice
No full textEthnopharmacological relevance: Cynometra cauliflora Linn. belongs to the Fabaceae family and is known locally in Malaysia as nam-nam. Traditionally, a decoction of the C. cauliflora leaves is used for treating hyperlipidemia and diabetes. Aim of the study: This study aims to investigate the anti-obesity and lipid lowering effects of ethanolic extract of C. cauliflora leaves and its major compound (vitexin) in C57BL/6 obese mice induced by high-fat diet (HFD), as well as to further identify the molecular mechanism underlying this action. Methods and material: Male C57BL/6 mice were fed with HFD (60% fat) for 16 weeks to become obese. The treatment started during the last 8 weeks of HFD feeding and the obese mice were treated with C. cauliflora leaf extract at 200 and 400 mg/kg/day, orlistat (10 mg/kg) and vitexin (10 mg/kg). Results: The oral administration of C. cauliflora (400 and 200 mg/kg) and vitexin significantly reduced body weight, adipose tissue and liver weight and lipid accumulation in the liver compared to control HFD group. Both doses of C. cauliflora also significantly (P ≤ 0.05) decreased serum triglyceride, LDL, lipase, IL-6, peptide YY, resistin levels, hyperglycemia, hyperinsulinemia, and hyperleptinemia compared to the control HFD group. Moreover, C. cauliflora significantly up-regulated the expression of adiponectin, Glut4, Mtor, IRS-1 and InsR genes, and significantly decreased the expression of Lepr in white adipose tissue. Furthermore, C. cauliflora significantly up-regulated the expression of hypothalamus Glut4, Mtor and NF-kB genes. GC-MS analysis of C. cauliflora leaves detected the presence of phytol, vitamin E and β-sitosterol. Besides, the phytochemical evaluation of C. cauliflora leaves showed the presence of flavonoid, saponin and phenolic compounds. Conclusion: This study shows interesting outcomes of C. cauliflora against HFD-induced obesity and associated metabolic abnormalities. Therefore, the C. cauliflora extract could be a potentially effective agent for obesity management and its related metabolic disorders such as insulin resistance and hyperlipidemia. © 2019 Elsevier B.V
A revision of the trapdoor spider genus Liphistius (Mesothelae: Liphistiidae) in Peninsular Malaysia; part 2
No full textThe currently known species of the Liphistius trang-growp in Peninsular Malaysia are revised on the basis of genital morphology and an identification key is given. Liphistius thaleban Schwendinger, 1990 and L. rufipes Schwendinger, 1995 are placed in the synonymy of L. yangae Platnick & Sedgwick, 1984. The previously unknown male of L. kanthan Platnick, in Platnick et al., 1997 is described for the first time. Liphistius kanthan and L. tempurung Platnick, in Platnick et al., 1997 are reported to occur together at the Tempurung Cave. Liphistius buran Schwendinger, sp. nov, an island species with a novel character of the palpal organ, is described from males and females. Information on and illustrations of intraspecific variation in most of these species is given together with data on biology and distribution. For selected Liphistius species in Malaysia a phylogenetic tree based on an analysis of COI sequences is presented and discussed in comparison with relationships inferred from morphological characters. Molecular data confirm the distinction between the malayanus-group and the trang-group in Malaysia, but, unlike an earlier interpretation of morphological evolution of genitalia, place species of the trang-group as basal to the malayanus-group. © 2019 Museum d'Histoire Naturelle de Geneve. All rights reserved
Fluorometric and Docking Analysis of the Complex Formation between an Anti-Cancer Drug, Chlorambucil and Bovine Serum Albumin
No full textBackground: To characterize the interaction between chlorambucil (CHB) and the carrier protein, bovine serum albumin (BSA) in order to understand the transport of this drug in blood circulation. Methods: Fluorescence quenching titration method was used to examine the interaction of CHB with BSA by determining its binding constant and binding stoichiometry. The binding site identification was probed with molecular docking techniques. Results: Values of the Stern-Volmer constant (KSV), bimolecular quenching rate constant (kq)and binding constant (K) for CHB-BSA system were determined a as 3.57×104 M−1, 5.67 × 1012 M−1 s−1 and 5.58 × 104 M−1, respectively. Binding stoichiometry was found to be ~1.0, as obtained from the double logarithmic plot. The molecular docking results revealed that CHB binds to both Site I and Site II of BSA, however Site II was predicted to be the preferred binding site. Conclusion: The value of Ka suggested intermediate binding affinity between CHB and BSA with the binding stoichiometry of 1:1. CHB was found to have the binding preference at Site II of BSA due to formation of greater contacts. © 2019, Association of Pharmaceutical Teachers of India. All rights reserved
Experimental and numerical studies on the premixed syngas swirl flames in a model combustor
No full textExperimental and numerical investigations were performed to study the combustion characteristics of synthesis gas (syngas) under premixed swirling flame mode. Four different type of syngases, ranging from low to high H2 content were tested and simulated. The global flame structures and post emission results were obtained from experimental work, providing the basis of validation for simulations using flamelet generated manifold (FGM) modelling approach via a commercial computational fluid dynamic software. The FGM method was shown to provide reasonable agreement with experimental result, in particular the post-exhaust emissions and global flame shapes. Subsequently, the FGM method was adopted to model the flame structure and predict the radical species in the reaction zones. Simulation result shows that H2-enriched syngas has lower peak flame temperature with lesser NO species formed in the reaction zone. © 2019 Hydrogen Energy Publications LL
A metabolomic approach to investigate effects of ocean acidification on a polar microalga Chlorella sp.
No full textOcean acidification, due to increased levels of anthropogenic carbon dioxide, is known to affect the physiology and growth of marine phytoplankton, especially in polar regions. However, the effect of acidification or carbonation on cellular metabolism in polar marine phytoplankton still remains an open question. There is some evidence that small chlorophytes may benefit more than other taxa of phytoplankton. To understand further how green polar picoplankton could acclimate to high oceanic CO2, studies were conducted on an Antarctic Chlorella sp. Chlorella sp. maintained its growth rate (∼0.180 d-1), photosynthetic quantum yield (Fv/Fm = ∼0.69) and chlorophyll a (0.145 fg cell-1) and carotenoid (0.06 fg cell-1) contents under high CO2, while maximum rates of electron transport decreased and non-photochemical quenching increased under elevated CO2. GCMS-based metabolomic analysis reveal that this polar Chlorella strain modulated the levels of metabolites associated with energy, amino acid, fatty acid and carbohydrate production, which could favour its survival in an increasingly acidified ocean. © 2019 Elsevier B.V
Heart rate variability and baroreflex sensitivity abnormalities in Guillain–Barré syndrome: a pilot study
No full textObjective: The current study aimed to investigate autonomic dysfunction in Guillain–Barré syndrome (GBS) patients and describe the results of computational heart rate variability (HRV)/baroreflex sensitivity (BRS) and autonomic challenge tests. Methods: GBS patients were consecutively recruited and the results were compared to age- and gender-matched healthy controls. A series of autonomic function tests including computation-dependent tests (power spectrum analysis of HRV and BRS at rest) and challenge maneuvers (deep breathing, eyeball compression, active standing, the Valsalva maneuver, sustained handgrip, and the cold pressor test) were performed. Results: Ten GBS patients (six men; mean age = 40.1 ± 13.9 years) and ten gender- and age-matched healthy controls were recruited. The mean GBS functional grading scale at disease plateau was 3.4 ± 1.0. No patients required intensive care unit admission or mechanical ventilation. Low-frequency HRV (p = 0.027), high-frequency HRV (p = 0.008), and the total power spectral density of HRV (p = 0.015) were significantly reduced in patients compared to controls. The mean up slope (p = 0.034), down slope (p = 0.011), and total slope (p = 0.024) BRS were significantly lower in GBS patients. The diastolic rise in blood pressure in the cold pressor test was significantly lower in GBS patients compared to controls (p = 0.008). Interpretation: Computation-dependent tests (HRV and BRS) were more useful for detecting autonomic dysfunction in GBS patients, whereas the cold pressor test was the only reliable challenge test, making it useful as a bedside measure of autonomic function in GBS patients. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
Distinctive Distribution of Secretory Phospholipases A2 in the Venoms of Afro-Asian Cobras (Subgenus: Naja, Afronaja, Boulengerina and Uraeus)
No full textThe protein abundances of phospholipases A2 in cobra venom proteomes appear to vary among cobra species. To determine the unique distribution of snake venom phospholipases A2 (svPLA2) in the cobras, the svPLA2 activities for 15 cobra species were examined with an acidimetric and a colorimetric assay, using egg yolk suspension and 4-nitro-3-octanoyloxy benzoic acid (NOBA) as the substrate. The colorimetric assay showed significant correlation between svPLA2 enzymatic activities with the svPLA2 protein abundances in venoms. High svPLA2 activities were observed in the venoms of Asiatic spitting cobras (Naja sputatrix, Naja sumatrana) and moderate activities in Asiatic non-spitters (Naja naja, Naja atra, Naja kaouthia), African spitters (subgenus Afronaja), and forest cobra (subgenus Boulengerina). African non-spitting cobras of subgenus Uraeus (Naja haje, Naja annulifera, Naja nivea, Naja senegalensis) showed exceptionally low svPLA2 enzymatic activities. The negligible PLA2 activity in Uraeus cobra venoms implies that PLA2 may not be ubiquitous in all snake venoms. The svPLA2 in cobra envenoming varies depending on the cobra species. This may potentially influence the efficacy of cobra antivenom in specific use for venom neutralization. © 2019 by the authors. Licensee MDPI, Basel, Switzerland