Search

Road transportation does an excellent job of connecting Savar's inner and outer areas, but it might be difficult for commuters to decide which mode of transportation to employ because residents of Savar come from a wide range of socioeconomic backgrounds. It is necessary to do in-depth research on the characteristics of people in the study region who choose different modes of transportation to achieve the goal of selecting a certain mode for their travel. Where a person lives can have a significant impact on their typical patterns of travel behavior. People who live closer to the center of things have access to a wider variety of amenities than those who live further away, and as a consequence, their travel patterns are distinct from one another. The study's findings indicate that several factors, including income, age, gender, and vocational qualities and goals, influence a commuter's preferred method of transportation. When it comes to selecting a mode of transportation, the most predictable factors to take into account are trip time and cost. After conducting research, it was found that most excursions are made from this place to Motijheel, Tejgaon, and Savar Export Processing Zone for their services, businesses, and jobs, respectively.

We investigated CO coverage (θCO) on Pt2Ru3 nanoparticle with various morphologies in H2/CO mixture gas atmosphere at 333 K by grand canonical ensemble Monte Carlo (GCMC) combined with quantitative structure–property relationship. In nanoparticles enclosed by (111) facets, θCO was significantly reduced when the surface and the subsurface were composed of Pt and Ru, respectively. The nanoparticles with homogeneously mixed surface showed low θCO, while the Janus-type showed high θCO. A similar tendency was obtained in the (100)-enclosed nanoparticle. These results revealed that the homogeneous mixing of Pt and Ru on the surface is essential to increase the CO tolerance. Graphical abstract

Introduction: Head and neck trauma includes many facial fractures as well as soft tissue injury to face, oropharyngeal injury and also trauma to neck. Head and neck trauma may or may not be associated with fractures like maxillofacial fractures or isolated fracture of nasal bone. Objective: To find out study on Head and Neck tumours presented in OPD of Shaheed Ziaur Rahman Medical College Hospital, Bogura, Bangladesh. Material and Methods: This retrospective study was done in the Department of ENT & Head-Neck Surgery, Shaheed Ziaur Rahman Medical College Hospital, Bogura, Bangladesh from July to December 2021. Total 51 inpatients with a diagnosis suggestive of head and neck trauma Data was collected for age, sex, address, type of admission (Emergency/OPD), mechanism of injury, site of injury, imaging including X-rays/CT scan wherever applicable and results, surgical therapy, type of anesthesia, hospital admission duration, complications, and follow-up and analyzed. Results: Of the 51 cases, most of them were adult age group 62.7%, the females were 37.3% (19) and 62.7% (32) were male. In our study patients were divided into three age groups; pediatric (0-14 years), adult (15-60 years) and geriatric (>60years). Most of the patients belonged to the adult age group. 13.7% had presented to emergency room (ER) and 86.3% presented to outpatient department (OPD). Fall was the most common mode of injury (100%) in both pediatric and elderly population and in adults RTA (42.10%) was the most common mode. In the type of injury most common in pediatrics was oral cavity and oropharyngeal injury (47.60%), in adult’s facial soft tissue injury (STI) and facial fractures (42.10%) were equally common and in geriatrics it was (100%). Concision: Adult males were prone to head and neck trauma mostly sustaining soft tissue injury (STI) and fractures due to RTA and physical assult. Injury to oral cavity and oropharynx and STI due to fall is common in extreme of ages. .......

Introduction: Ear diseases have been found to be important health problems among children. Nearly one third of Otorhinolaryngology outdoor attendance in the hospital comprised of paediatric age group. The problem is compounded by the fact that the children are economically dependent on their parents who are largely poor. However, the cause of hearing loss in children is more varied, including the etiologies. Objective: To find out ear diseases in children presenting at Shaheed Ziaur Rahman Medical College Hospital, Bogura, Bangladesh. Materials and Methods: This hospital-based prospective study was carried at Department of ENT & Head-Neck Surgery, Shaheed Ziaur Rahman Medical College Hospital, Bogura, Bangladesh from January to December 2021. 985 patients below sixteen years of age presented to the ENT OPD during the study period. Of them, 450 had ear disease. All patients aged 16 years or younger presenting with ear diseases to the ENT clinic of the hospital and seen by ENT surgeons were enrolled into the study. The diagnoses were made on the basis of history and clinical examination. Results were expressed in numbers and percentages. Results: Out of 985 patients below sixteen years of age presented to the ENT OPD during the study period. Of them, 450 had ear disease. Five hundred and sixty one (64.4%) were males. The male to female sex ratio was 1.8:1. Table 2 the various types of ear disease were as CSOM (Chronic Suppurative Ottitis Media), ASOM (Acute Suppurative Ottitis Media) and OME (Ottitis Media with Effusion). Wax (33.6%) followed by CSOM (18.7%) and ASOM (13.8%) were the most common ear diseases in paediatric patients in tertiary care centre. Ear diseases commonly found in this study were in the age group of 6-10 years and most ear diseases were more common in boys. It was found that wax (33.6%) was the most common diagnosed ear disease. Conclusion: Ear diseases are most common condition in ENT OPD among paediatric age group. Wax, CSOM and ASOM were the three most common ear diseases. Improvement of health care facilities and awareness amongst health care providers would definitely be helpful in reducing the prevalence of ear diseases in developing countries.

Sore throat manifested by throat pain is a troublesome issue or discomfort for which physicians are used to prescribing antibiotics, but most often, it is found that the patient is not responding to the drug, which gives rise to the question of drug-resistant or whether there is any infection at all? Nonspecific throat pain also imparts serious public health problems. Self-medication, inadvertent and inadequate doses of antibiotics frequently prescribed by both village doctors and registered MBBS doctors is really a public health problem in developing countries like Bangladesh. Aims: The aims of this study are to isolate the common organisms in chronic throat infection and to find out the effectiveness of various commonly used antibiotics. Methods: The samples were collected randomly from sore throat patients via a throat swab in 5 ml of 1% sterilized saline water, and the sample was brought to the laboratory and was inoculated within two hours in both blood agar and nutrient agar (NA) media and samples were incubated at 37°C overnight. Then pure colonies were transferred to Mueller Hinton agar, and antimicrobial susceptibility testing was done by the Kirby Bauer disc diffusion method. Results: A total of 27(24%) out of 111 samples yield positive growth. In a large number of samples, 84 (76%) did not show any isolation of the pathogenic organism. The predominant organism is a Staphylococcus aureus (55.55%). Thereafter, streptococcus (18.51%), Klebsiellapneumone (14.81%)and Pseudomonas (11.11%).Amoxiclav is the most resistant drug, along with cefuroxime, azithromycin, and doxycycline, respectively. Levofloxacin and ciprofloxacin show intermediate sensitivity. The most sensitive drug used in chronic sore throat found is linezolid though not frequently used, and other sensitive drugs are moxifloxacin and ceftriaxone. Conclusion: Throat pain or soreness does not always indicate that patient has been infected by bacteria. Rationale and ethical prescription, as well as microbiological sensitivity testing, are considered to avoid drug-resistant strains. TAJ 2022; 35: No-1: 25-31

The objective of this study was to figure out the prevalence and probable causes of repeat breeding (RB) in dairy cows. Hence, a cross-sectional study was conducted on randomly selected 265 dairy farms in Sirajganj, Bogura, Rangpur, Satkhira, and Munshiganj districts of Bangladesh from December 2018 to February 2019. Data were collected through a direct interview method using a survey questionnaire. The reproductive organs of repeat breeder cows were examined for anatomical defects, pathological, infectious, functional reasons, and genital tract abnormalities. Additionally, the influence of nutrition, season, and age on the frequency of RB was recorded. Of the 3824 cows examined, the prevalence of RB was 28%. In this study, 98% of RB cases were exhibited in crossbred cows (Holstein-Friesian, 73%) than the indigenous (2%) cows. The prevalence of RB was significantly highest (P P P P

This study presents a novel multilevel inverter structure that can operate in both switched capacitor and asymmetric DC source modes. In the first mode, it can produce seven-level output voltage employing two switched capacitors and one single DC supply. The five-level output voltage is produced while operating the second mode. The voltage ratio between the input and output voltage for the capacitor mode is 1:3 (triple voltage gain). During the first mode, the capacitor of the inverter is self -balanced whereas the inverter can produce higher voltage output in the DC source mode. The proposed inverter reduces the total standing voltage in both modes of operations as it can generate the output voltage without requiring any additional H-bridge circuit. The feasibility and predominate features of the proposed inverter have been established by comparing with existing topologies in terms of power components count. Results obtained from this study are validated using simulation employing sinusoidal pulse width modulation (SPWM). A hardware prototype has also been developed for further validation.

In this work, molecular dynamics (MD) study of triglyme (G3) solution containing lithium bis (trifluoro methyl sulfonyl) amide (Li[TFSA]) were investigated using classical atomistic force fields. G3 is a typical solvent used in non-aqueous Li-air battery. It shows here coordination of Li+ with G3 and [TFSA]- does not significantly change with increasing the concentration of G3 but self-diffusion coefficient of all the ions increases with increasing G3 concentration. The density of [Li(G3)[TFSA] complex decreases with increasing G3 concentration which lead to accelerate diffusivity of ions. Bangladesh Journal of Physics, 27(1), 13-22, June 2020

This paper addresses the implementation of the new generalized ((G')⁄G)-expansion method to the Caudrey-Dodd-Gibbon (CDG) equation and the Lax equation which are two special case of the fifth-order KdV (fKdV) equation. The method work well to derive a new variety of travelling wave solutions with distinct physical structures such as soliton, singular soliton, kink, singular kink, bell-shaped soltion, anti-bell-shaped soliton, periodic, exact periodic and bell type solitary wave solutions. Solutions provided by this method are numerous comparing to other methods. To understand the physical aspects and importance of the method, solutions have been graphically simulated. Our results unquestionably disclose that new generalized ((G')⁄G)-expansion method is incredibly influential mathematical tool to work out new solutions of various types of nonlinear partial differential equations arises in the fields of applied sciences and engineering.

Heavy metal pollution in groundwater is a substantial environmental risk for Bangladesh. The Meghna Ghat industrial area in Bangladesh becomes a promising site for installing various industries for few decades. It was necessary to assess the heavy metal level in the groundwater of this area, and current study took the initiative. We collected 20 groundwater samples and tested pH, DO, TDS, EC, turbidity, COD, and DOC as well as four heavy metals (Cr, Cd, Pb, and Ni) to calculate four water quality indices, i.e., water quality index (WQI), degree of contamination (DC), heavy metal evaluation index (HEI), and heavy metal pollution index (HPI). Ni was too low to detect by the instrument, whereas the mean concentrations of Cr, Cd, and Pb were 0.07, 0.007, and 0.18 mg/L which exceeded the drinking water standards set by Bangladesh. According to the water quality indices, only 10% samples were good according to WQI; 30% and 15% samples were subjected to low level of pollution considering DC and HEI, respectively. Although according to HPI 35% samples were unsuitable for drinking, rest of the values were very close to characterize as unsuitable. Finally, we proposed two best-fitted models that can represent relationships between the metals and water quality indices. Water quality was comparatively better near the open spaces of the study area. The area needed to be under continuous monitoring for checking further pollution distribution.

Organizations nowadays are increasingly impacting in using strategic management to improve their performance; this study has mainly focused on the impact of strategic management on the performance of Choppies Enterprises. Choppies Enterprise Botswana-based Choppies is an investment holding company operating in the retail sector across sub-Saharan Africa. Its operations are food and general merchandise retailing as well as financial services transactions supported by centralized distribution channels, through distribution centers and logistical support assets in Botswana, South Africa, Zimbabwe, Kenya, and Zambia. This study focused on the strategic management of Choppies Enterprises. The main research problem was to make an in-depth analysis of its competitive strategy and how to implement it. The main research method was qualitative research by analyzing their company data, annual reports, and making interviews with the manager, staff, and customers in Botswana shops. The result shows a clear image of the process of strategic management by Choppies' case. Some recommendations made for Choppies help to improve their sustainable developments and support a vivid example for many companies. In the theoretical part, it described the definition, process, benefit, and challenge of strategic management. In the practical part, an exhaustive analysis of the company's strengths, weaknesses, opportunities, and threats was made by using the detailed figures.

This was a cross sectional descriptive study conducted to assess the effect pictorial warning message on cigarette packets to the attitude and practice of smokers using a semi-structured questionnaire employing purposive sampling technique with a sample size of 214 by face to face interview carried out in different cities, towns, and villages of Bangladesh from August 2016 to February 2017. Almost 97.6% were male and Most of the respondents (40.9%) belonged to the 20-29 years age group. Majority (58.3%) of them were educated from secondary to graduate few percent below primary. Highest 22.9% respondents were students followed by 17.6% private job holder, 16.9% day labor and only 1.4% was jobless. About 40.2% started smoking by the influence of friends, 26.2% started on curiosity and 20% due to depression and majority 41.0% smoked 1-5 cigarette sticks per day. More than half (65.5%) of respondents felt relax to refreshing by smoking and about two third 77.6% continued their smoking due to habitual act or psychological pleasure Almost 93.4% gave attention to the pictorial warning on the cigarette packets. About 46.4% thought pictorial warning in cigarette packets alarms for not to smoke and only 23.8% thought smoking will cause cancer; 21.4% thought smoking is injurious to health. After seeing the pictorial warning on cigarettes 57.6% reduced the smoking number of sticks per day also attempted to quit smoking. To reduce this restricting the advertisement of tobacco, arranging campaign to raise awareness among people about the health and environmental hazards of smoking and increase the tax on tobacco.

Background Aggression towards nurses in the workplace arises from various reasons, reportedly increasing during the COVID-19 pandemic. Where aggression can be maintained by spiritual well-being, as it is said that spirituality is a coping skill and psychological well-being maintainer–but there is little known, especially during the pandemic. Thus, this study explored the effect of spirituality on aggression among the nurses working in the COVID-19 wards. Methods This cross-sectional data from 200 nurses involved in the COVID-19 patient treatment were collected using a random sampling method from four hospitals in East Mazandaran province, Iran. Responses were collected based on socio-demographics, Buss-Perry Aggression Questionnaire, and Paloutzian & Ellison Spiritual Well-being Scale. T-test, ANOVA, Pearson correlation coefficient, and multiple linear regression were applied for data analysis. Results The mean age of nurses was 31.49±6.88 (range: 21–48) years. Nurses working in the COVID-19 wards have a mean score of spiritual health of 67.21±12.84 (out of 120), whereas 51.77±10.96 (out of 116) was for aggression. The results showed a significant negative weak correlation between aggression and spiritual health (r = -.285, pp Conclusions It is evident that nurses who consider spirituality in their life actions are in a state of reduced negative emotions, such as aggression. Thus, policymakers and managers of the healthcare settings are suggested to promote spirituality among the nurses through spiritual care education, providing the ground for promoting spirituality and a positive attitude towards it.

This article addresses the implementation of the new generalized $$\left( {G^{\prime } /G} \right)$$ -expansion method to the Caudrey–Dodd–Gibbon (CDG) equation and the Lax equation which are associated with the fifth-order KdV (fKdV) equation. The method works well to derive a variety of standard and functional closed-form wave solutions with distinct physical structures, such as, soliton, kink, periodic soliton, and bell-shaped soliton solutions. The solutions obtained using this method are useful and adequate than other methods. In order to understand the physical aspects and importance of the method, the attained solutions have been simulated graphically. The extracted results definitely establish that the new generalized $$\left( {G^{\prime } /G} \right)$$ -expansion method is an effective mathematical tool to work out new solutions to different types of local nonlinear evolution equations emerging in applied science and engineering, but this method is not effective in solving nonlocal equations.

Despite the fact that leaf decomposition constitutes an important function in rivers, how multiple environmental stressors simultaneously affect it remains largely unknown. This study investigated the interactive effects of fine sediments (particle size: &lt, 2 mm, experimentally manipulated) and a specific nutrient (i.e., nitrate) on subsurface (hyporheic) leaf litter decomposition rate and macroinvertebrates in a gravel-bed river and its tributary in eastern Hokkaido, Japan. The experiment was conducted by measuring leaf litter decomposition of dried Alnus japonica leaves (3 ± 0.05 g) in benthic and hyporheic zones with and without sediment treatments at four sites that had a gradient of nitrate concentration. The decomposition rate was comparable between the two zones but was slowed down by sediment addition in the hyporheic zone. The functional responses were highly predictable for the individual stressors. Detritivore invertebrates were the main driving component of decomposition in the decreased leaf litter decomposition rate under a higher fine sediment condition, whereas higher nitrate accelerated the leaf litter decomposition rate by stimulated microbe-driven decomposition as well as detritivore feeding. Overall, the negative effect of fine sediment could be offset in the presence of nitrate while considering gross functional responses. We demonstrated the additive effects of fine sediment and nitrate on leaf litter decomposition in the hyporheic zone.

In this article, we establish the exact wave solutions of the Boussinesq equation and the (2 + 1)-dimensional extended shallow water wave equation by applying the new generalized ( G ' / G ) -expansion method. When the condition of the fluid is such that the horizontal length scale is much greater than the vertical length scale, the shallow water equations are mostly suitable. In Ocean engineering, Boussinesq-type equations are commonly used in computer simulations for the model of water waves in shallow seas and harbors. We explained the new generalized ( G ' / G ) -expansion method to seek further general traveling wave solutions of the above mentioned equations. The traveling wave solutions attained by this method are exposed in terms of hyperbolic, trigonometric and rational functions. The shape of the obtained solutions are bell shaped soliton, kink soliton, singular kink soliton, singular soliton, singular periodic solution and compaction. This method is very influential mathematical tool for extracting exact solutions of NLEEs which frequently arise in mathematical physics, engineering sciences and many scientific real world application fields.

Predicting electronically excited states across electron-donor/electron acceptor interfaces is essential for understanding the charge photogeneration process in organic solar cells. However, organic solar cells are large and disordered systems, and their excited states cannot be easily accessed by conventional quantum chemistry approaches. Moreover, a large number of excited states must be obtained to fully understand the charge separation mechanism. Recently, we have developed a novel fragment-based excited state method which can efficiently calculate a large number of states in molecular aggregates. In this article, we demonstrate the large-scale excited-state calculations by investigating interfacial charge transfer (ICT) states across the electron-donor/electron acceptor interfaces. As the model systems, we considered the face-on and edge-on configurations of pentacene/C60 bilayer heterojunction structures. These model structures contain approximately 1.8 × 105 atoms, and their local interface regions containing 2000 atoms were treated quantum mechanically, embedded in the electrostatic potentials from the remaining parts. Therefore, the charge delocalization effect, structural disorder, and the resulting heterogeneous electrostatic and polarizable environments were taken into account in the excited-state calculations. The computed energies of the low-lying ICT states are in reasonable agreement with experimental estimates. By comparing the edge-on and face-on configurations of the pentacene/C60 interfaces, we discuss the influence of interfacial morphologies on the energetics and charge delocalization of ICT states. In addition, we present the detailed characterization of excited states and highlight the importance of hybridization effects between pentacene excited states and ICT states. The large-scale ab initio calculations for the interface systems enabled the exploration of the ICT states, leading to first-principles investigation of the charge separation mechanism in organic solar cells.

The life-history traits of amphibitic insects are not well understood. These insects inhabit saturated interstitial areas below the riverbed (hyporheic zone) at the larval stage, mate in terrestrial habitats, and return to rivers for oviposition, but there is no knowledge concerning their dispersal characteristics. We sought to address this by examining how far amphibitic insects disperse away from the channel (laterally) and along upstream or downstream (longitudinally) in a gravel-bed river. Alloperla ishikariana was selected as the focal species because it numerically dominates other amphibites in an 18-km study segment of a 4th-order gravel-bed river in Hokkaido, Northern Japan. Malaise traps were set at various distances from the channel towards the riparian forest to estimate lateral dispersal distances. An elevated stable nitrogen isotope ratio in downstream larvae, caused by the influence of effluent from a wastewater treatment plant, was used to assess longitudinal dispersal by identifying and tracking adult movements. Laterally, 50th and 90th percentile dispersal distances were 11.66 and 35.09 m for female A. ishikariana and 20.59 and 59.20 m for male, respectively; this overlapped with distances previously estimated for other aquatic benthic taxa. Longitudinally, 50th and 90th percentile dispersal distances were 0.74 and 1.43 km for female and 3.11 and 7.87 km for male, respectively. Alloperla ishikariana had one of the longest upstream traveling distances compared with other aquatic insects, and the longest among Plecoptera taxa known thus far where male exhibited a greater dispersal distance. A higher number of adults demonstrated upstream movement, suggesting an upstream bias in the longitudinal dispersal of A. ishikariana. Overall, amphibitic stoneflies did not exhibit distinct dispersal characteristics compared with the results of previous reports on presumably benthic taxa. Our findings support an improved visualization of a multi-dimensionally connected river ecosystem in terms of material flow, including vertical connectivity.

Durability of organo-lead halide perovskite are important issue for its practical application in a solar cells. In this study, using density functional theory (DFT) and molecular dynamics, we theoretically investigated a crystal structure, electronic structure, and ionic diffusivity of the partially substituted cubic MA0.5X0.5PbI3 (MA = CH3NH3+, X = NH4+ or (NH2)2CH+ or Cs+). Our calculation results indicate that a partial substitution of MA induces a lattice distortion, resulting in preventing MA or X from the diffusion between A sites in the perovskite. DFT calculations show that electronic structures of the investigated partially substituted perovskites were similar with that of MAPbI3, while their bandgaps slightly decrease compared to that of MAPbI3. Our results mean that partial substitution in halide perovskite is effective technique to suppress diffusion of intrinsic ions and tune the band gap.

In this study, the density functional theory (DFT) and Monte Carlo (MC) simulations were conducted to determine the equilibrium conformation of Pt2Ru3 nanoparticles with diameters 1.0–3.5 nm at finite temperature. DFT calculations were carried out to estimate the binding energy using slab configurations and energy could be correlated with some structural descriptors and multilinear regression equations to calculate the binding energy from descriptors related to the number of a specific bond to neighboring atoms. MC simulations were carried out to obtain the equilibrium conformation of atoms in Pt2Ru3 at 150–363 K. MC simulations’ result shows that atoms of the same element tend to segregate each other, and Pt/Ru ratio on the surface increases with increasing particle size; also, most of the Pt are located on the surface whereas most of the Ru are located on the subsurface or at the core sites. It is qualitatively exhibited that the Pt/Ru ratio on the surface decreases with increasing temperature.

We present classical molecular dynamics (MD) and first principles molecular dynamics (FPMD) studies to investigate the transport mechanisms of hydroxide ions through poly(arylene ether sulfone ketone)s containing quaternized ammonio-substituted fluorenyl groups (QPE) as anion exchange polymers used in applications such as alkaline fuel cells. The effect of the number of repeating units in QPE on the ion conductivity of hydroxide ions was investigated by classical MD. Calculated ion conductivities are almost the same regardless of the number of repeating units in QPE and are consistent with the experimental values. The microscopic structures of water distribution in hydrated QPE were also investigated. Analysis of radial distribution functions (RDFs) of atoms calculated by classical MD implies the possibility of two different interacting conformations of hydroxide ions and ammonium groups in hydrated QPE. Distinct peaks in the RDF of O(hydroxide ion)–N(QPE) means that diffusion of hydroxide ions in hydrated QPE is mainly governed by surface diffusion, i.e., hopping between the ammonium groups of QPE, when the vehicle transport occurs. Transport of hydroxide ions based on the Grotthuss mechanism was also investigated by FPMD. The results show that hydroxide ion transport occurs with the formation of H 3 O 2 − through the hydrogen network of the water molecules. The formed H 3 O 2 − cleaves into H 2 O and OH − , resulting in proton exchange between a water molecule and a hydroxide ion, which is similar to the proton transfer mechanism observed in proton exchange membranes.

Undoped and manganese (Mn)-doped zinc oxide (ZnO) thin films have been deposited onto glass substrates at 300[Formula: see text]C using a low cost spray pyrolysis technique. Structural, optical and electrical properties of the as-deposited films have been investigated. Scanning electron microscopy images show the existence of clusters with well-defined nucleation centers consisting of highly dense ganglia-like fibers over a large area around the nucleation center. Chemical compositions of the ZnO and Mn-doped ZnO thin films are studied by using energy dispersive X-ray (EDX) analysis. X-ray diffraction spectra depict that the films have polycrystalline wurtzite structure. The average crystallite sizes are calculated in the range of 8–16 nm by Williamson–Hall method and found in good agreement with Scherer method. Optical transmittance of the films is about 80% in the visible region. Bandgap energy is tuned to 2.83 eV from 3.10 eV with increasing Mn doping. Electrical resistivity at room-temperature decreases significantly with increasing Mn doping as well as increasing temperature from 300–440 K. The activation energies in the temperature ranges 300–350 K and 350–440 K are found to be in the range of 0.25–0.16 eV and 0.35–0.59 eV, respectively. Hall Effect measurements show that the thin films have negative Hall co-efficient indicating [Formula: see text]-type conductivity at room-temperature. Carrier concentration is found to be of the order of 10[Formula: see text] cm[Formula: see text].

The purpose of this research was to establish an effective dose of gamma irradiation to eliminate any possible bacterial contamination as well as assess the levels of essential major elements [sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) and iron (Fe)] present in black tea. The samples were compared to fresh tea leaves and soil from the tea gardens of two distinct tea cultivating regions (Sylhet and Moulvibazar) in Bangladesh. Maximum coliform bacterial contaminants (4.0 × 102 cfu/g) were completely eliminated following an irradiation dose of 2.5 kGy, whereas a viable bacterial load of 9.0 × 103 cfu/g was completely eliminated at 5.0 kGy. Major elements were present at higher concentrations in black tea samples originating from Sylhet compared to those from Moulvibazar. Among the analyzed elements, only Na and Fe were present at higher concentrations in the fresh tea leaves from Sylhet, whereas K, Ca and Mg were observed at higher concentrations in the tea leaves from Moulvibazar. The amount of each mineral in the black tea is acceptable for daily intake and is safe for consumption. It is concluded that black tea from Bangladesh is a rich source of minerals and could be free of microbial contamination after receiving 5.0 kGy of gamma radiation.

This paper presents a periodic density functional theory study on the adsorption of H, CO, and OH on Pt2Ru3 alloy surfaces containing different conformations of Pt and Ru atoms. The results show that for separate adsorption, H is preferentially adsorbed at Pt sites, whereas CO and OH are preferentially adsorbed at Ru sites. The adsorption strengths of H, CO, and OH are affected by ratio of the alloying atoms in top surface, the nature of the neighboring atom nearest to the adsorption site, and the conformation of alloying atoms in subsurface. We also investigated the coadsorption of CO with OH and the coadsorption of CO with H and found that the Pt–CO bond strength weakens. We also uncovered some information about the competitive adsorption behavior of adsorbates (CO, OH) with the aim of designing CO-tolerant Pt–Ru alloy catalysts.

Third-generation solar cells are understood to be the pathway to overcoming the issues and drawbacks of the existing solar cell technologies. Since the introduction of graphene in solar cells, it has been providing attractive properties for the next generation of solar cells. Currently, there are more theoretical predictions rather than practical recognitions in third-generation solar cells. Some of the potential of graphene has been explored in organic photovoltaics (OPVs) and dye-sensitized solar cells (DSSCs), but it has yet to be fully comprehended in the recent third-generation inorganic-organic hybrid perovskite solar cells. In this review, the diverse role of graphene in third-generation OPVs and DSSCs will be deliberated to provide an insight on the prospects and challenges of graphene in inorganic-organic hybrid perovskite solar cells.

Bio-assessment protocols for the subsurface domain of river channels (i.e. hyporheic zone) are scarce despite of the known importance of its ecological function in river ecosystems. The larvae of the Alloperla ishikariana Plecoptera species inhabit the hyporheic zone. Therefore, we examined whether emergent adult A. ishikariana could serve as proxy indicators of the effects of pollution in the hyporheic food web. The study site comprised a 15-km stretch of a gravel bed river in Hokkaido, Japan, from which all invertebrates were collected from the riverbed at a depth of 30–50 cm, and emergent A. ishikariana adults were sampled in riparian zones. Water quality changed gradually along the river owing to the effects of a wastewater treatment plant and surrounding land uses. Nitrogen and carbon stable isotope ratios (SIRs) of epilithic biofilms, hyporheic particulate organic matter (POM), benthic POM, and invertebrates were used to determine the major basal carbon sources, the effects of water pollution on the hyporheic zone, and the trophic positions of dominant invertebrates. Generalized linear (mixed) models were used for statistical testing and modeling. Amphipoda and the larvae of A. ishikariana were considered as top predators and secondary consumers in the hyporheic food web, respectively. The observed similarity in water quality between the hyporheic and surface water suggested a large degree of hydrological exchange between the two zones, and resulted in positive increases in the nitrogen SIRs of hyporheic invertebrates, including A. ishikariana larvae, in proportion to nitrate levels in the surface water. The nitrogen SIRs of A. ishikariana adults were significantly correlated with the nitrogen SIRs of their larvae within the same location (adjusted R2 = 0.78), indicating that emerged adults can provide information on the longitudinal variability of the effects of synthetic nitrogen. In contrast, the carbon SIRs of adults did not predict those of their larvae, possibly reflecting the diverse feeding habitats of larvae. Overall, we demonstrated that adult aquatic insects emerging from the hyporheic zone can be used as indirect indicators of pollution-associated nutrient assimilation as well as the spatial heterogeneity of dietary carbon resources in hyporheic food web.

In this paper, the performance of multi-hop free-space-optical (FSO) communications systems over atmospheric turbulence fading channel along with pointing error effects is analyzed considering Pulse Position Modulation (PPM). The analysis is done under weak atmospheric turbulence i.e. Lognormally distributed and transmission using multi-hop which is established on amplify-and-forward relays. We illustrate combined probability density function for multi-hop FSO system. The numerically found results show that the multihop transmission along with M-ary PPM is a good solution for obtaining desired Bit Error Rate (BER) under the effects of weak turbulence and pointing error.

Psoriasis is a T-cell mediated chronic inflammatory diseases where pro-inflammatory mediators are involved in its pathogenesis. Alpha-2-macroglobulin (α-2M) is a panproteinase inhibitor having unique clearing role of different cytokines. This study was conducted on 30 patients with moderate to severe psoriasis to see the plasma level of α-2M and was compared with the normal healthy controls. Patients who were already selected for systemic treatment (methotrexate) and consented for routine blood test for monitoring at baseline and 12 weeks after treatment were enrolled along with 10 healthy controls. The venous blood (5 mL) was collected and the plasma alfa-2 macroglobulin was estimated using the enzyme-linked immunosorbent assay. The mean plasma α-2M level was 3.0 ± 0.4 g/L among the normal healthy persons, and 2.8 ± 0.7 g/L among the untreated patients of psoriasis (p>0.05). Its level among the patients with psoriasis after systemic antipsoriatic drugs was 2.8 ± 0.6 g/L which was not significantly different from the baseline level (p>0.05). The study shows that the plasma α-2M level in psoriasis is not different comparing with normal healthy persons.

Pt-based material are commonly used as electrocatalysts for low temperature fuel cells. The Pt metal surface is easily poisoned by trace amount of CO, especially in fuel cells [1]. CO is also present in H2produced by stream reforming of methanol, ethanol and hydrocarbon fuels, it is also a problem in hydrogen fuel cells [2]. Among the most studied catalysts, the supported platinum based particles have been exhibited a notable efficiency for limiting CO poisoning. Most practical anode fuel cell catalysts consist of platinum nanoparticles alloyed by a second components are Ru, Mo and Sn, which have been studied in many recent surface electrochemistry studies. Among the binary systems the Pt-Ru combination has proved to be most successful at enhancing electro-catalytic activity [3]. The carbon CO itself is usually assumed to follow a so-called bifunctional mechanism, originally suggested by Watanbe and Motoo. [4]. In this mechanism, Ru sites act as adsorption centers for the oxygen-containing surface species reacting with the CO to produce CO2. Attempts have been made to develop catalysts that either enhance the oxidation of adsorbed CO or simply tolerate CO better, or both, by alloying Pt with other metals. The improvement of the catalytic performance requires an understanding of the reaction mechanism at the atomistic level. There are many studies have been performed for CO adsorption and oxidation on the Pt and Pt-based alloys in order to design highly CO tolerant bimetallic catalysts but there is few studies regarding atomistic scale and dynamical phenomena of the CO adsorption and oxidation mechanism. A combined molecular dynamics (MD)/density-functional theoretical (DFT) study of the electro-oxidation of CO at the Pt-Ru alloy interface is very important to provide insights into the reaction mechanism. All calculations were performed using DFT under the generalized gradient approximation with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. A double numerical basis set augmented with polarization functions were used in the optimization. The computational method used in the present study is implemented in the DMol3 [5]. First-principles molecular dynamics is performed to know the dynamical properties of CO/Pt-Ru interface during the CO oxidation process. To simulate the mentioned first we determined the most stable initial state on each surface. The Pt(111)-(CO+O) and Pt-Ru (111)-(CO+O) system where O adsorbs on the hollow site and CO on the atop site with the carbon head closer to the surface. From previous findings it is assumed that Pt-metal alloy shows more reactivity than pure Pt for CO oxidation but very few studies regarding atomistic level and dynamical characteristics of this oxidation process. From our combined MD and DFT study we expect we will be able to examine electronic and geometric change of Pt-metal and its role of CO oxidation process. In our MD calculation we would be able to know temperature effect on Pt-Ru alloy surface as well as CO oxidation mechanism on this bimetallic surface. We also want to investigate how the Pt-Ru alloy structure change by CO and H2O adsorption using MD. Reference: H.A. Gasteiger, N. Markovic, P.N. Ross Jr., E.J. Cairns, J. Phys.Chem B. 98, 617 (1994) H. Gasteiger, N. Markovic, P. Ross, J. Phys. Chem. 99, 8945 (1995) M.Watanabe, M. Uchida, S. Motoo, J. Electroanal. Chem. 229, 395 (1987) M.Watanabe, S. Motoo, J. Electroanal. Chem. 60, 275 (1975) B. Delley, J. Chem. Phys. 92,508 (1990)

In the recent years, interest has grown in the development of anion exchange membranes (AEMs) for alkaline fuel cells, which have advantage over proton exchange membranes (PEM) fuel cells including cost and performance. In this work, we present molecular dynamics (MD) and first principles molecular dynamics (FPMD) studies to investigate transport mechanisms of OH- using quanternized multiblock copoly(arylene ether) (QPE) and poly (phthalazinone ether sulfone keton) (PPESK) anion exchange polymers. We report here Grotthus and vehicle mechanisms for OH- transport by molecular modeling. From our MD study for OH- diffusion in the QPE and PPESK, diffusion properties is comparable to experimental report and OH- transport mechanisms from FPMD simulation significantly differ with proton transport processes.

It is well established that the catalytic properties of metal can be markedly changed by alloying with a second metal in polymer electrolyte fuel cells [1]. Pt-Ru alloys are known to substantially improve the catalytic performance in the electrochemical oxidation of CO from CO contaminated hydrogen fuels. The presence of small amounts of CO that are carried over in the H2 feed from the reformer act to poison Pt surface sites. The addition of Ru to Pt helps to prevent CO poisoning of the Pt surface sites that carry out H2 oxidation. Ru promotes the catalytic oxidation of CO to form CO2 and may also weaken the Pt-CO interaction. Most practical anode fuel cell catalysts consist of Pt nanoparticles alloyed by a second components are Ru, Mo and Sn. Among the binary systems the Pt-Ru combination has proved to be most successful at enhancing electro-catalytic activity [2]. The CO itself is usually assumed to follow a so-called bifunctional mechanism, originally suggested by Watanbe and Motoo [3]. For H2 oxidation in the presence of CO, Watanabe and Motoo have proposed a combined mechanism, in which the ligand and bifunctional effects may coexist [2,4]. The improvement of the catalytic performance requires an understanding of the reaction mechanism at the atomistic level. Multi-scale simulation study of the electro-oxidation of CO at the Pt-Ru alloy interface is very important to provide new insights into the reaction mechanism. All calculations were performed using density functional theory (DFT) under the generalized gradient approximation with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional and Monte Carlo (MC) simulation method. The computational method used in the present study is implemented in the DMol3 [5]. MC simulation has been performed to know the stability of Pt-Ru alloy catalysts during CO oxidation processes. Pt-Ru surface is modeled as a five layer slabs with Pt:Ru (2:3) ratio. Initially, we have checked the surface stability of Pt-Ru surface with different positions of Pt and Ru remaining same mixing ratio. We found that fcc based Pt-Ru alloy shows higher stability than the hcp based alloy and we also confirmed that the surface coverage with Pt atoms indicates stable combination. We also notice that 2nd layer positioned with Ru atoms shows higher stability than the other combinations. As a whole the tendency indicates, top surface contains Pt sufficiency and 2nd layer contains Ru sufficiency make the structure stable. Model of Pt-Ru surface where CO are located on the atop, bridge and hollow sites were also examined. We found that the well mixing of Pt by Ru leads to a weaker bond of CO on the surfaces. Many studies assumed that Pt-metal alloy shows more reactivity than pure Pt for CO oxidation but very few studies regarding atomistic level. Coverage change of Pt on the surface of alloy catalysts is further studied by MC simulations. Based on the DFT calculations we correlate the binding energy of alloy catalysts with different Pt coverage. From our MC simulation study we successfully modeled the temperature effect on Pt-Ru alloy surface change as well as CO poisoning influence to Pt coverage of this bimetallic surface. References V. Ponce, G.C. Bond, Catalysis by Metals and Alloys; Studies in Surface Science and Catalysis 95; Elsevier: Amsterdam, 1995. M.Watanabe, M. Uchida, S. Motoo, J. Electroanal. Chem. 229, 395 (1987) M.Watanabe, S. Motoo, J. Electroanal. Chem. 60,275 (1975) M. Watanabe, M. Shibata, S. Motoo, J. Electroanal. Chem. 206, 197 (1986) B. Delley, J. Chem. Phys. 92, 508 (1990)

In this study, we investigated the presence of 19 different agricultural pesticides in 210 samples of eight types of domestic vegetables collected from several vegetable-growing regions in Bangladesh. A multiresidue method was developed to detect the pesticide levels in the collected samples using gas chromatography with mass spectrophotometry (GC–MS). Pesticide residues were detected in 51.30% of the total samples, and among the positive samples, 38.89% contained levels above the maximum residue levels (MRLs). The most frequently detected pesticides were chlorpyrifos (34) followed by carbofuran (17), diazinon (16), carbaryl (14), malathion (11), endosulfan (8), cypermethrin (7) and dimethoate (6). Some (10.47%) of the samples contained multiple residues. It is concluded that the continuous monitoring and strict regulation of pesticide use on food crops, especially vegetables, are necessary.