1,417 research outputs found
Microarray screening of Guillain-Barré syndrome sera for antibodies to glycolipid complexes
Objective: To characterize the patterns of autoantibodies to glycolipid complexes in a large cohort of Guillain-Barré syndrome (GBS) and control samples collected in Bangladesh using a newly developed microarray technique.
Methods: Twelve commonly studied glycolipids and lipids, plus their 66 possible heteromeric complexes, totaling 78 antigens, were applied to polyvinylidene fluoride–coated slides using a microarray printer. Arrays were probed with 266 GBS and 579 control sera (2 μL per serum, diluted 1/50) and bound immunoglobulin G detected with secondary antibody. Scanned arrays were subjected to statistical analyses.
Results: Measuring antibodies to single targets was 9% less sensitive than to heteromeric complex targets (49.2% vs 58.3%) without significantly affecting specificity (83.9%–85.0%). The optimal screening protocol for GBS sera comprised a panel of 10 glycolipids (4 single glycolipids GM1, GA1, GD1a, GQ1b, and their 6 heteromeric complexes), resulting in an overall assay sensitivity of 64.3% and specificity of 77.1%. Notable heteromeric targets were GM1:GD1a, GM1:GQ1b, and GA1:GD1a, in which exclusive binding to the complex was observed.
Conclusions: Rationalizing the screening protocol to capture the enormous diversity of glycolipid complexes can be achieved by miniaturizing the screening platform to a microarray platform, and applying simple bioinformatics to determine optimal sensitivity and specificity of the targets. Glycolipid complexes are an important category of glycolipid antigens in autoimmune neuropathy cases that require specific analytical and bioinformatics methods for optimal detection
Low loss topas based porous core single mode photonic crystal fiber for THz communications
In this paper, an extremely low loss hybrid hexagonal porous core and octagonally structured circular cladding photonic crystal fiber (PCF) for low loss terahertz (THz) wave propagation has been designed and proposed. We have analyzed ultralow effective material loss (EML), high core power fraction and ultra-flattened dispersion in our proposed design. To investigate the transmission characteristics, perfectly matched layer (PML) is used in the outer boundary of the PCF. At an operating frequency of 1 THz, this design exhibits a low effective material loss of 0.045 cm-1 at a high core power fraction of 58.2% with 88% porosity. The proposed PCF shows dispersion variation of 0.225 ps/THz/cm. Also, this designed PCF can operate in single-mode condition successfully. It is anticipated that designed PCF can be employed in applications such as fiber optics communications, sensing and spectroscopy
Topas based high birefringent and low loss single mode hybrid-core porous fiber for broadband application
We present a through numerical analysis of a low loss and highly birefringent hybrid porous core with octagonal cladding structure for terahertz (THz) wave guidance. The proposed photonic crystal fiber (PCF) offers simultaneously low effective material loss (EML) as well as high birefringence in the frequency range of 0.8-1.05 THz with single mode operation. To attain high birefringence we introduce asymmetry in the core using both elliptical and circular air holes (hybrid). The numerical results obtained from the finite element method (FEM) which confirms low EML of 0.044 cm–1 as well as a high birefringence of ~0.043 at 0.73 THz operating frequency. Therefore, the fiber is likely to be useful in different THz polarization maintaining applications
Design and concept of renewable energy driven auto-detectable railway level crossing systems in Bangladesh
Bangladesh’s railway system mostly uses typical manual railway crossing techniques or boom gates through its 2955.53 km rail route all over the country. Accidents frequently happen at railway crossings due to the lack of quickly operating gate systems, and to fewer safety measures at the railway crossing as well. Currently, there are very few automatic railway crossing systems available (without obstacle detectors). Additionally, all of them are dependent on the national power grid, without a backup plan for any emergency cases. Bangladesh is still running a bit behind in generating enough power for its consumption; hence, it is not possible to have a continuous power supply at all times all over the countryside. We aim to design and develop a smart railway crossing system with an obstacle detector to prevent common types of accidents at railway crossing points. We use two infrared (IR) sensors to operate the railway crossing systems, which are controlled by an Arduino Uno. This newly designed level crossing system is run with the help of sustainable renewable energy, which is cost-effective and eco-friendly, and applied under the national green energy policy towards achieving sustainable development in Bangladesh as a part of the global sustainable goal to face climate change challenges. We have summarized the simulated the results of several renewable energy sources, including a hybrid system, and optimized the Levelized Cost of Energy (LCOE) and the payback periods
Pathways to antibiotics in Bangladesh: a qualitative study investigating how and when households access medicine including antibiotics for humans or animals when they are ill
Background
To understand how to reduce antibiotic use, greater knowledge is needed about the complexities of access in countries with loose regulation or enforcement. This study aimed to explore how households in Bangladesh were accessing antimicrobials for themselves and their domestic animals.
Methods
In-depth interviews were conducted with 48 households in one urban and one rural area. Households were purposively sampled from two lower income strata, prioritising those with under 5-year olds, older adults, household animals and minority groups. Households where someone was currently ill with a suspected infection (13 households) were invited for a follow-up interview. Framework analysis was used to explore access to healthcare and medicines.
Findings
People accessed medicines for themselves through five pathways: drugs shops, private clinics, government/charitable hospitals, community/family planning clinics, and specialised/private hospitals. Drug shops provided direct access to medicines for common, less serious and acute illnesses. For persistent or serious illnesses, the healthcare pathway may include contacts with several of these settings, but often relied on medicines provided by drug shops. In the 13 households with an unwell family member, most received at least one course of antibiotics for this illness. Multiple and incomplete dosing were common even when prescribed by a qualified doctor. Antibiotics were identified by their high cost compared to other medicines. Cost was a reported barrier to purchasing full courses of antibiotics. Few households in the urban area kept household animals. In this rural area, government animal health workers provided most care for large household animals (cows), but drug shops were also important.
Conclusions
In Bangladesh, unregulated drug shops provide an essential route to medicines including those prescribed in the formal sector. Wherever licensed suppliers are scarce and expensive, regulations which prohibit this supply risk removing access entirely for many people
Prevalence of multidrug resistance bacterial isolates from infected wound patients in Dhaka, Bangladesh: A cross-sectional study
Abstract Introduction Multidrug resistance (MDR) is threatening the adequate coverage of antibiotics. This study aimed to analyze the antimicrobial resistance pattern of bacterial isolates from wound infection and the scenario of multidrug resistance. Methods Microbiological culture results scripts of Medinova Medical Services LTD, representing non-repetitive various wound samples (post-surgical, trauma, superficial skin, burn) reported between January 2017 and March 2018, were retrieved and analyzed for pathogens and their antimicrobial resistance patterns using R version 3.5.3. Results Overall, 1266 bacterial isolates were obtained, and 850 (67.1%) were identified as MDR. The percentage of MDR among gram-positive and gram-negative bacterial isolates were 68.8% and 66.0%, respectively. Among isolates Staphylococcus aureus (n = 401), Pseudomonas aeruginosa (n = 200), and Escherichia coli (n = 193) were predominant. Vancomycin followed linezolid showed most activity against gram-positive bacteria. Whereas, Colistin was found to be the most active against most of the gram-negative bacterium except for the Proteus spp in sensitivity test. Although, carbapenem group was determined to be the best against Proteus spp. About 82% Enterococcus spp and 76% Proteus spp were MDR. Isolates from patients aged >60 years (AOR = 1.774 95%CI: 1.089–2.892) were more prone to becoming MDR in compared to other age group and was a significant determinant (P = 0.02) of MDR. Conclusions Our study revealed that the presence of MDR pathogens in wound infection was noteworthy. The findings of this study would assist in decision making of wound infection treatment
Exploring the metabolic landscape of pancreatic ductal adenocarcinoma cells using genome-scale metabolic modeling
Pancreatic ductal adenocarcinoma (PDAC) is a major research focus because of its poor therapy response and dismal prognosis. PDAC cells adapt their metabolism to the surrounding environment, often relying on diverse nutrient sources. Because traditional experimental techniques appear exhaustive to find a viable therapeutic strategy, a highly curated and omics-informed PDAC genome-scale metabolic model was reconstructed using patient-specific transcriptomics data. From the model-predictions, several new metabolic functions were explored as potential therapeutic targets in addition to the known metabolic hallmarks of PDAC. Significant downregulation in the peroxisomal beta oxidation pathway, flux modulation in the carnitine shuttle system, and upregulation in the reactive oxygen species detoxification pathway reactions were observed. These unique metabolic traits of PDAC were correlated with potential drug combinations targeting genes with poor prognosis in PDAC. Overall, this study provides a better understanding of the metabolic vulnerabilities in PDAC and will lead to novel effective therapeutic strategies
Synthesis, Characterization and Bioactivities of Some Novel Oxovanadium(IV) Glycinato Complexes
The novel oxovanadium(IV) complexes, [VIVO(GlyH)(Gly)]+ClO4 - .H2O (1), [VIVO(GlyH)(Gly)]+NO3 - .H2O (2), [VIVO(GlyH)(Gly)]+CH3COO- .H2O (3) were synthesized and characterized by FT-IR, UV-Vis and 1H NMR spectroscopic measurements. The cumulative spectroscopic assessment envisaged that, the complexes adopt a square pyramidal structure, in which the two glycine ligands coordinate to vanadium(IV) center in bidentate fashions conforming a homoleptic structure. The amino nitrogen and a carboxylato oxygen atom coordinate the vanadium(IV) center from both sides making a five members chelate by each side. All the complexes are stable in amorphous state and in aerobic and anaerobic solution. Significantly, all the complexes have the antifungal activities against Aspergillus niger and Penicillium notatum but ineffective against Candida tropicalis. No antibacterial activity was observed for the complexes against tested bacteria and unfortunately, they were found cytotoxic against brine shrimp bioassay
Multicellular Models Bridging Intracellular Signaling and Gene Transcription to Population Dynamics
Cell signaling and gene transcription occur at faster time scales compared to cellular death, division, and evolution. Bridging these multiscale events in a model is computationally challenging. We introduce a framework for the systematic development of multiscale cell population models. Using message passing interface (MPI) parallelism, the framework creates a population model from a single-cell biochemical network model. It launches parallel simulations on a single-cell model and treats each stand-alone parallel process as a cell object. MPI mediates cell-to-cell and cell-to-environment communications in a server-client fashion. In the framework, model-specific higher level rules link the intracellular molecular events to cellular functions, such as death, division, or phenotype change. Cell death is implemented by terminating a parallel process, while cell division is carried out by creating a new process (daughter cell) from an existing one (mother cell). We first demonstrate these capabilities by creating two simple example models. In one model, we consider a relatively simple scenario where cells can evolve independently. In the other model, we consider interdependency among the cells, where cellular communication determines their collective behavior and evolution under a temporally evolving growth condition. We then demonstrate the framework\u27s capability by simulating a full-scale model of bacterial quorum sensing, where the dynamics of a population of bacterial cells is dictated by the intercellular communications in a time-evolving growth environment
Synthesis, Characterization And Electrolytic Behavior Of Cadmium(II) Complexes Of 5,7,7,12,14,14- Hexamethyl-1,4,8,11-Tetraazacyclotetradeca-4,11- Diene And Isomers Of Its Saturated Analogue
Condensation of ethylendiamine with acetone in the presence of quantitative amount of perchloric acid, yielded the ligand 5,7,7,12,14,14- hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene dihydroperchlorate (denoted by L.2HClO4). The ligand L.2HClO4 on reduction with NaBH4, yielded an isomeric mixture of saturated macrocycles, the Me6[14]anes, which were resolved into two distinct C-chiral isomers (denoted by ‘tet-a’ and ‘tet-b’). Interaction of ligands L.2HClO4, ‘tet-a’ and ‘tet-b’ with salts CdI2, Cd(NO3)2.4H2O, CdCl2.2H2O and Cd(ClO4)2.6H2O produced different five coordinated square pyramidal and six coordinated octahedral cdmium(II) complexes. Among them the complexes, cis-[Cd(teta)( NO3)](NO3) and cis-[Cd(tet-b)(NO3)](NO3) underwent axial ligand substitution reaction with KCNS; whereas complex [Cd(tet-a)I2] underwent axial ligand substitution reaction and complex [CdLI](ClO4) underwent simultaneous ligand substitution and addition reaction with NaNO2. Characterization of all the complexes were carried out on the basis of elemental analysis; FT-IR, UV-Vis. and 1H-NMR spectroscopy; melting point determination as well as by magnetic moment and conductivity measurements. Molar conductivity measurment of the complexes reavealed that they show different electrolytic behavior in different solvents
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