Bifunctional Zirconium Phosphate with Greigite for Electrochemical Detection and Simultaneous Removal of Heavy Metal Ions and Nitro Compounds.

Electrochemical sensing is emerging as a method of choice for the sensing and monitoring of contaminants in water. Various sensing platforms have been designed for sensing heavy metal ions and organic pollutants in water bodies. Herein, we report a new electrochemical platform that can be used for the detection of both heavy metal ions and nitro-based organic contaminants in water bodies. The electrochemical sensor uses a modified electrode based on Fe3S4-impregnated zirconium phosphate (ZrP) nanoparticles synthesized by a simple ultrasonication method. The ZrP@Fe3S4 nanoparticles were thoroughly characterized by power X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), and ζ-potential studies. The material exhibits an excellent electrochemical performance for the detection of Pb2+, Hg2+, nitrophenol, nitroaniline, and picric acid with low limits of detection of ca. 0.93, 0.70, 0.98, 1.10, and 1.53 ppm, respectively. Since ZrP@Fe3S4 nanoparticles are magnetically recyclable, their adsorption capacity and recyclability have been thoroughly investigated for the uptake of Pb2+ and Hg2+ ions from contaminated water. We observed that the adsorption of Pb2+ and Hg2+ ions on ZrP@Fe3S4 is best described by the Langmuir isotherm and pseudo-second-order kinetic models, with adsorption capacities of 219.44 and 118.4 mg/g, respectively. Similarly, the removal efficiency of ZrP@Fe3S4 was found to be 91, 57.6, and 31.3% for nitrophenol, nitroaniline, and picric acid, respectively. Furthermore, the theoretical calculations using density functional theory (DFT) were carried out to find the adsorption energy, affinity, and point of adsorption, which are in line with the experimental results. DFT calculations further suggest that the incorporation of Fe3S4 on ZrP improves the surface charge density and promotes efficient electron transfer between the electrode and the analyte. We have shown the real-time analysis of Dal lake water as a proof of concept, and the synthesized composite exhibits good recovery and promising results for metal ion sensing. ZrP@Fe3S4 demonstrated an excellent cycling stability and long-term stability without noticeable degradation for 1 week.

Bangladeshi Native Vehicle Classification Based on Transfer Learning with Deep Convolutional Neural Network.

Vehicle type classification plays an essential role in developing an intelligent transportation system (ITS). Based on the modern accomplishments of deep learning (DL) on image classification, we proposed a model based on transfer learning, incorporating data augmentation, for the recognition and classification of Bangladeshi native vehicle types. An extensive dataset of Bangladeshi native vehicles, encompassing 10,440 images, was developed. Here, the images are categorized into 13 common vehicle classes in Bangladesh. The method utilized was a residual network (ResNet-50)-based model, with extra classification blocks added to improve performance. Here, vehicle type features were automatically extracted and categorized. While conducting the analysis, a variety of metrics was used for the evaluation, including accuracy, precision, recall, and F1 - Score. In spite of the changing physical properties of the vehicles, the proposed model achieved progressive accuracy. Our proposed method surpasses the existing baseline method as well as two pre-trained DL approaches, AlexNet and VGG-16. Based on result comparisons, we have seen that, in the classification of Bangladeshi native vehicle types, our suggested ResNet-50 pre-trained model achieves an accuracy of 98.00%.

Synthesis of 3,5-dihydroxy-7,8-dimethoxy-2-(4-methoxyphenyl)benzopyran-4-one derivatives as anticancer agents.

Different alkyl amide (15a-l) and alkyl amine (16a-e) derivatives of 7,8-dimethoxy-3-hydroxy-2-(4-methoxyphenyl)benzopyran-4-one were synthesized and evaluated for their anticancer activity against five different cancer cell lines using SRB assay. Compounds 15e, 15i, 15j and 16a-e showed significant anticancer activity within the range of IC50 2.58-34.86µM. The most promising molecule, 16c, was further analyzed for its effect on cell cycle and apoptosis of estrogen receptor positive cancer cells (MCF-7 cells) which showed that 16c triggered apoptosis in MCF-7 cells and arrested cells population at sub-G0 (apoptotic) and G2M phase. In tubulin polymerization assay, 16c interfered with kinetics of tubulin polymerization.

Clustering of home delivery in Bangladesh and its predictors: Evidence from the linked household and health facility level survey data.

Around half of births in Bangladesh occur at home without skilled birth personnel. This study aims to identify the geographical hot spots and cold spots of home delivery in Bangladesh and associated factors. We analyzed data from the 2017/2018 Bangladesh Demographic and Health Survey and the 2017 Bangladesh Health Facility Survey. The outcome variable was home delivery without skilled personnel supervision (yes, no). Explanatory variables included individual, household, community, and healthcare facility level factors. Moran's I was used to determine hot spots (geographic locations with notably high rates of home delivery) and cold spots (geographic areas exhibiting significantly low rates of home delivery) of home delivery. Geographically weighted regression models were used to identify cluster-specific predictors of home delivery. The prevalence of without skilled personnel supervised home delivery was 53.18%. Hot spots of non-supervised and unskilled supervised home delivery were primarily located in Dhaka, Khulna, Rajshahi, and Rangpur divisions. Cold spots of home delivery were mainly located in Mymensingh and Sylhet divisions. Predictors of higher home births in hot spot areas included women's illiteracy, lack of formal job engagement, higher number of children ever born, partner's agriculture occupation, higher community-level illiteracy, and larger distance to the nearest healthcare facility from women's homes. The study findings suggest home delivery is prevalent in Bangladesh. Awareness-building programs should emphasize the importance of skilled and supervised institutional deliveries, particularly among the poor and disadvantaged groups.

DFT Studies on a Metal Oxide@Graphene-Decorated D-π1-π2-A Novel Multi-Junction Light-Harvesting System for Efficient Dye-Sensitized Solar Cell Applications.

Graphene nanocomposites have emerged as potential photoanode materials for increased performance of the dye-sensitized solar cells (DSSCs) via charge transfer. Various metal-oxide-decorated graphene nanocomposites have widespread applications in energy devices, such as solar cells, fuel cells, batteries, sensors, electrocatalysis, and photocatalysis. However, the possible role of these composites in DSSC applications has largely remained unexplored. Herein, we studied a Sb2O3-decorated graphene-D-π1-π2-A sensitized TiO2 nanocomposite (dye-(TiO2)9/Sb2O3@GO) as a model multi-junction light-harvesting system and examined the impact of various π-bridges on the optical and photovoltaic properties of the push-pull dye system employed in this light-harvesting system. We have shown that by changing the spacer unit, the light sensitivity of nanocomposites can be varied from visible to near-infrared wavelengths. Furthermore, with the integration of metal-oxide-decorated graphene nanocomposites on D-π1-π2-A systems and D-π-A systems, composite photoelectrodes displayed better optical and photovoltaic characteristics with an enhanced absorption spectrum in the wavelength range of 800-1000 nm. The performance of the D-π1-π2-A system has been evaluated in terms of various photovoltaic parameters such as the highest occupied molecular orbital-lowest unoccupied molecular orbital energy gaps, excited-state oxidation potential (E dye *), free energy of electron injection (G inject), total reorganization energy (λtotal), and open-circuit voltage (V oc). This work throws light on the current trends and the future opportunities in graphene-metal oxide nanocomposite-based DSSCs for better harvesting of the solar spectrum and better performance of solar devices.

Electrochemical analysis of glyphosate using porous biochar surface corrosive nZVI nanoparticles.

Glyphosate [N-(phosphonomethyl)glycine] is a widely used phosphonate herbicide for different agricultural purposes. Due to its widespread use, suspected toxicity, and ubiquitous bioaccumulation, it is one of the most harmful contaminants found in drinking water. This demands efficient sensing and removal of glyphosate from contaminated water. Here, we report the decoration of novel and highly porous biochar with nanozero-valent iron (nZVI) nanoparticles to develop an efficient electrochemical sensor for the trace detection of glyphosate. The as-synthesized composite was thoroughly characterized by various state-of-the-art instrumental techniques. The electron micrographs of the composite materials revealed the cavity-like structure and the abundant loading of nZVI nanoparticles. FTIR and XPS analyses confirmed the presence of oxygen-rich functionalities and Fe(0) in the composite nanostructure. Electrochemical analysis through CV, LSV, and DPV techniques suggested efficient sensing activity with a limit of detection as low as 0.13 ppm. Furthermore, the chronopotentiometric response suggested excellent and superior stability for long-term applications. To gain more insight into the interaction between glyphosate and the composite material, DFT calculations were carried out. The Frontier Molecular Orbital study (FMO), Molecular Electrostatic Potentials (MEPs), and Density of States (DOS) suggest an increase in the electron density, an increase in the DOS, and a decrease in the HOMO-LUMO band gap by combining nZVI nanoparticles and biochar. The results suggest more facile electron transfer from the composite for trace detection of glyphosate. As a proof of concept, we have demonstrated that real-time analysis of milk, apple juice, and the as-synthesized composite shows promising results for glyphosate detection with an excellent recovery rate.

Characterization of two novel lytic bacteriophages having lysis potential against MDR avian pathogenic Escherichia coli strains of zoonotic potential.

Avian pathogenic E. coli (APEC) is associated with local and systemic infections in poultry, ducks, turkeys, and many other avian species, leading to heavy economical losses. These APEC strains are presumed to possess zoonotic potential due to common virulence markers that can cause urinary tract infections in humans. The prophylactic use of antibiotics in the poultry sector has led to the rapid emergence of Multiple Drug Resistant (MDR) APEC strains that act as reservoirs and put human populations at risk. This calls for consideration of alternative strategies to decrease the bacterial load. Here, we report isolation, preliminary characterization, and genome analysis of two novel lytic phage species (Escherichia phage SKA49 and Escherichia phage SKA64) against MDR strain of APEC, QZJM25. Both phages were able to keep QZJM25 growth significantly less than the untreated bacterial control for approximately 18 h. The host range was tested against Escherichia coli strains of poultry and human UTI infections. SKA49 had a broader host range in contrast to SKA64. Both phages were stable at 37 °C only. Their genome analysis indicated their safety as no recombination, integration and host virulence genes were identified. Both these phages can be good candidates for control of APEC strains based on their lysis potential.

Improving the sensitivity of blood culture for Streptococcus pneumoniae.

Isolation of Streptococcus pneumoniae is jeopardized by low sensitivity of blood culture, autolysis and contamination with fast-growing organism(s). We performed an immunochromatographic (ICT) test for S. pneumoniae on chocolatized blood culture bottles and also sub-cultured contaminated bottles on a selective medium, thus identifying an additional eight and three cases, respectively, and improving the detection of pneumococcus by 23% (48% vs. 59%). Prescreening of culture bottles in a blinded fashion could rationalize the use of ICT with ~99% accuracy. These two approaches can aid microbiology laboratories in resource-poor countries to substantially improve rates of detection of S. pneumoniae.

Surveillance for invasive Streptococcus pneumoniae disease among hospitalized children in Bangladesh: antimicrobial susceptibility and serotype distribution.

BACKGROUND: Vaccines offer the prospect of primary disease prevention of pneumococcal disease in childhood. For introduction of such vaccines in developing countries, information about disease epidemiology is necessary. METHODS: We evaluated antimicrobial susceptibility and serotype distribution of invasive Streptococcus pneumoniae disease in children aged <5 years in a network of 7 hospitals in Bangladesh from May 2004 through May 2007. RESULTS: Of 17,969 blood cultures and 3765 cerebrospinal fluid cultures, 139 yielded S. pneumoniae isolates; 94 were from meningitis cases, 13 were from pneumonia cases, and 32 were from sepsis cases. Among the children with positive culture results, 73% were aged <12 months and 90% were aged <24 months. Complete resistance against penicillin, chloramphenicol, and cotrimoxazole was found in 0%, 6%, and 32% of isolates, respectively. Of the 37 serotypes observed, the predominant serotypes were 2 (17%), 1 (12%), 14 (7%), 5 (6%), 7F (6%), 45 (7%), and 12A (4%). Serotypes differed between meningitis cases and nonmeningitis cases, especially for serotype 2 (25% of meningitis cases vs. 0% of pneumonia cases; P < .001). The 7-, 10-, and 13-valent vaccines would cover 20% (95% confidence interval [CI], 13%-27%), 43% (95% CI, 35%-51%), and 50% (95% CI, 42%-58%) of these cases of invasive pneumococcal disease overall, with higher coverage of nonmeningitis cases, compared with meningitis cases (7-valent coverage, 23% vs. 18%; 10-valent coverage, 55% vs. 38%; 13-valent coverage, 66% vs. 42%). CONCLUSIONS: High levels of nonsusceptibility to cotrimoxazole and susceptibility to penicillin suggest that penicillin may be a drug of choice for treatment of invasive pneumococcal disease. Although serotype distribution is diverse, with changes over time and differences between syndromes observed, implementation of use of the currently available 10- or 13-valent vaccines would have a substantial impact on pneumococcal disease in Bangladesh.

Invasive pneumococcal disease among children in rural Bangladesh: results from a population-based surveillance.

BACKGROUND: Streptococcus pneumoniae infection is recognized as a global priority public health problem, and conjugate vaccines have been shown to prevent vaccine-type invasive pneumococcal disease (IPD) in children. However, better estimates of the disease burden and reliable population-based data on serotype composition are needed for vaccine development and implementation in developing countries. METHODS: We initiated a population-based surveillance in the rural Bangladesh community of Mirzapur, covering a population of approximately 144,000. Village health care workers made weekly visits to approximately 12,000 children 1-59 months of age in the study area. Children with reported fever, cough, or difficulty breathing were assessed by the village health care workers using a clinical algorithm and were referred to the hospital if required. Children from the study area who were seen in the hospital underwent clinical examination and laboratory testing if they met standardized case definitions. IPD was confirmed by blood and/or cerebrospinal fluid culture results. Isolates were identified, tested for susceptibility to antibiotics, and serotyped in accordance with standard laboratory methods. We present here the results from the first 3 years of the surveillance (July 2004-June 2007). RESULTS: Village health care workers identified 5020 cases of possible severe pneumonia and/or very severe disease (165 cases per 1000 child-years)and 9411 cases of possible pneumonia (310 cases per 1000 child-years) as well as 2029 cases of suspected meningitis and/or very severe disease (67 cases per 1000 child-years) and 8967 cases of high fever and/or possible bacteremia (295 cases per 1000 child-years). Pneumonia was the single most common form of illness observed among 2596 hospitalizations (found in 977 [38%] of cases). We recovered 26 S. pneumoniae isolates (25 isolates from 6925 blood cultures and 1 isolate from 41 cerebrospinal fluid cultures), which gave an overall IPD incidence of 86 cases per 100,000 child-years. Invasive pneumococcal infection was common during infancy (with infants accounting for 23 of the 26 cases), and 50% of the total isolates were obtained from nonhospitalized patients who received a diagnosis of upper respiratory tract infection and fever. The most prevalent pneumococcal serotypes were serotypes 1, 5, 14, 18C, 19A, and 38. Ten of the 26 isolates were completely resistant to trimethoprim-sulfamethoxazole, and another 10 isolates had intermediate resistance. CONCLUSIONS: IPD contributes substantially to childhood morbidity in rural Bangladesh. S. pneumoniae can cause invasive but nonsevere disease in children, and IPD incidence can be seriously under reported if such cases are overlooked. The emerging high resistance to trimethoprim-sulfamethoxazole should be addressed. Data on serotype distribution would help to guide appropriate pneumococcal conjugate vaccine formulation.

Effect of alcoholic beverages on postprandial glycemia and insulinemia in lean, young, healthy adults.

BACKGROUND: Ethanol's ability to inhibit gluconeogenesis might reduce postprandial glycemia in realistic meal settings. OBJECTIVE: The objective was to explore the effect of 3 types of alcoholic beverages consumed alone, with a meal, or 1 h before a meal on postprandial glycemia in healthy subjects. DESIGN: In study 1, isoenergetic (1000 kJ) servings of beer, white wine, and gin were compared with a 1000-kJ portion of white bread. In study 2, the same servings were compared with water as an accompaniment to a bread meal. In study 3, 20-g alcohol portions were served as a premeal drink. Fingertip capillary blood samples were taken at regular intervals over 2-3 h. RESULTS: In study 1, the mean (+/-SE) glucose scores for beer (58 +/- 11), wine (7 +/- 3), and gin (10 +/- 5) were significantly lower (P < 0.001) than those for bread (= 100). In study 2, meals consumed with beer (84 +/- 11; P = 0.03), wine (63 +/- 6; P < 0.001), and gin (80 +/- 12; P = 0.007) produced less glycemia than did the meal consumed with water (= 100). In study 3, all 3 beverages reduced the postprandial glycemic response to the subsequent meal (67 +/- 5, 75 +/- 6, and 78 +/- 4 with the beer, wine, and gin trials, respectively; P < 0.003). CONCLUSION: In realistic settings, alcoholic beverage consumption lowers postprandial glycemia by 16-37%, which represents an unrecognized mechanism by which alcohol may reduce the risk of chronic disease.

Population-based incidence and etiology of community-acquired neonatal bacteremia in Mirzapur, Bangladesh: an observational study.

BACKGROUND: To devise treatment strategies for neonatal infections, the population-level incidence and antibiotic susceptibility of pathogens must be defined. METHODS: Surveillance for suspected neonatal sepsis was conducted in Mirzapur, Bangladesh, from February 2004 through November 2006. Community health workers assessed neonates on postnatal days 0, 2, 5, and 8 and referred sick neonates to a hospital, where blood was collected for culture from neonates with suspected sepsis. We estimated the incidence and pattern of community-acquired neonatal bacteremia and determined the antibiotic susceptibility profile of pathogens. RESULTS: The incidence rate of community-acquired neonatal bacteremia was 3.0 per 1000 person-neonatal periods. Among the 30 pathogens identified, the most common was Staphylococcus aureus (n = 10); half of all isolates were gram positive. Nine were resistant to ampicillin and gentamicin or to ceftiaxone, and 13 were resistant to cotrimoxazole. CONCLUSION: S. aureus was the most common pathogen to cause community-acquired neonatal bacteremia. Nearly 40% of infections were identified on days 0-3, emphasizing the need to address maternal and environmental sources of infection. The combination of parenteral procaine benzyl penicillin and an aminoglycoside is recommended for the first-line treatment of serious community-acquired neonatal infections in rural Bangladesh, which has a moderate level of neonatal mortality. Additional population-based data are needed to further guide national and global strategies.

Medical teaching websites: do they reflect the learning paradigm?

Phenomenal evolution of the Internet in recent times is shifting the mode of distribution of medical knowledge from conventional lecture rooms to one that is web based. No guidelines are yet set for medical teaching websites. Hence, the authors set out to determine whether these sites uniformly reflected the Learning Paradigm. Most of the medical teaching websites were endowed with good technical support but were surprisingly falling short in reflecting the principles of learning. It is strongly suggested that a team consisting of a clinician as content provider, a web designer and a medical educationist is required to create an ideal medical teaching website.