Cs2TiI6 (Cs2TiIxBr6-x) Halide Perovskite Solar Cell and Its Point Defect Analysis.

This work presents a comprehensive numerical study for designing a lead-free, all-inorganic, and high-performance solar cell based on Cs2TiI6 halide perovskite with all-inorganic carrier transport layers. A rigorous ab initio density-functional theory (DFT) calculation is performed to identify the electronic and optical properties of Cs2TiI6 and, upon extraction of the existing experimental data of the material, the cell is designed and optimized to the degree of practical feasibility. Consequently, a theoretical power conversion efficiency (PCE) of 21.17% is reported with inorganic TiO2 and CuI as carrier transport layers. The calculated absorption coefficient of Cs2TiI6 reveals its enormous potential as an alternative low-bandgap material for different solar cell applications. Furthermore, the role of different point defects and the corresponding defect densities on cell performance are investigated. It is found that the possible point defects in Cs2TiI6 can form both the shallow and deep defect states, with deep defect states having a prominent effect on cell performance. For both defect states, the cell performance deteriorates significantly as the defect density increases, which signifies the importance of high-quality material processing for the success of Cs2TiI6-based perovskite solar cell technology.

Molecular identification, antimicrobial resistance and virulence gene profiling of Staphylococcus spp. associated with bovine sub-clinical mastitis in Bangladesh.

This study was conducted to investigate the diversity and antimicrobial resistance profiling of Staphylococcus species causing sub-clinical mastitis (SCM) in dairy herds in Bangladesh as well as putative risk factors associated with the infections. Individual quarter milk samples were collected from a total of 284 lactating cows from 30 dairy farms were screened by means of California mastitis test; 178 (62.7%) of them had at least of quarter affected by SCM. After conventional microbiological isolation procedures, PCR tests were used for Staphylococcus species identification and detection of antimicrobial resistance and virulence genes. S. chromogenes (65.7%) was the most predominant species followed by, S. epidermidis (20.2%), S. haemolyticus (19.1%), S. aureus (15.7%), and S. sciuri (5.6%). High levels of antimicrobial resistance to ampicillin and amoxicillin/clavulanic acid were observed in S. aureus (82.1% and 75%) and S. sciuri (80% and 70%), while resistance to cefepime was markedly higher in S. chromogenes (95.7%), S. haemolyticus (94.1%), and S. epidermidis (97.2%). Multidrug resistance isolates were identified in all five species. The mecA gene was detected in S. aureus (32.1%) and S. chromogenes (5.98%). In addition, 20% S. sciuri and 17.7% S. haemolyticus carried the cytotoxin (pvl) gene, while 14.3% S. aureus harbored the toxic shock syndrome toxin (tst) gene. Multivariable logistic regression analysis identified "Old aged" (OR [CI]: 3.5 [1-12.4]); "Early stage of lactation" (OR [CI]: 3.4 [1.2-9.7]) and, "Firm udder condition" (OR [CI]: 4.2 [1.2-14.6]) as risk factors associated with SCM caused by S. aureus, S. chromogenes, and S. haemolyticus, respectively. Moreover, "Use of antimicrobials" (OR [CI]: 10.4 [3.4-32.1] and "History of previous clinical mastitis" (OR [CI]: 4.9 [1.2-19.7] for the carriage of methicillin-resistant Staphylococcus spp.

Prevalence of gastrointestinal parasitic infections in wild mammals of a safari park and a zoo in Bangladesh.

In safari parks and zoos, wild animals are kept mainly for recreational purposes. Animals in these enclosures are also crucial for the education, research, and conservation aspect. To ensure better management and good health of wild animals in captivity, it is essential to monitor the occurrence of gastrointestinal (GI) parasitic (helminths and protozoa) infections. The current investigation was undertaken to investigate the prevalence of GI parasitic infections in wild mammals at Bangabandhu Sheikh Mujib (BSM) safari park and Chattogram (CTG) zoo of Bangladesh. A total of 72 individual faecal samples were collected from 25 species of wild mammals. Routine qualitative (e.g. direct smear, sedimentation, and flotation) and quantitative (e.g. McMaster technique) tests were performed to identify the eggs or oocysts of helminths and protozoa. Results demonstrated that wild mammals of both BSM safari park and CTG zoo were infected with a total of 17 genera/species of helminths and protozoa. The overall prevalence of GI parasitic infections in wild mammals of both zoological parks was 65.3% (95% confidence interval [CI]: 53.14-76.12), whereas it was 72.4% (95% CI: 52.76-87.27) in the BSM safari park and 60.5% (95% CI: 44.41-75.02) in the CTG zoo. In both zoological parks, infection with nematodes was more frequent compared to other helminth into the wild mammals. The herbivores were more infected with GI parasites than carnivores and omnivores of both BSM safari park and CTG zoo. The mean eggs/oocysts per gram of faeces was the highest in the carnivores compared to herbivores and omnivores of both enclosures. The findings of the current study demonstrated that wild mammals of both BSM safari park and CTG zoo suffered from various GI parasitic infections. Regular monitoring along with proper therapeutic measures may reduce the severe consequences of GI parasitic infections in captive wild animals.

Prevalence of helminth and protozoan infections in pet birds of Chattogram, Bangladesh.

BACKGROUND: Parasitic diseases such as helminths and protozoa are considered one of the major impediments in the rearing of pet birds. The current study was undertaken to determine the prevalence of helminths and protozoal infections in different captive pet birds in Chattogram metropolitan area, Bangladesh. METHODS: A total of 549 pooled faecal and 311 individual blood samples were collected from different species of pet birds during June 2019 to May 2020. The faecal samples were examined following routine microscopic tests to identify the eggs and oocysts of helminths and protozoan parasites, respectively. Polymerase chain reaction (PCR) was performed to determine the haemoprotozoan parasites. RESULTS: The prevalence of helminth infestations in pet birds was 8.01% (95% confidence interval [CI]: 5.88-10.61), where infestation caused by nematodes was the highest (7.47%, CI: 5.41-10). Ascaridia and Capillaria spp. infestations were the commonest helminths recorded in different groups of pet birds. The overall prevalence of intestinal protozoal infections was 11.11% (CI: 8.61-14.04) in pet birds. The most commonly occurring protozoal infections were Eimeria spp. (7.83%, CI: 5.73-10.41) followed by Isospora spp. (2.91%, CI: 1.67-4.69). The overall prevalence of haemoprotozoan parasites was 2.25% (CI: 0.91-4.58) in different groups of pet birds. The highest prevalence was recorded in Plasmodium spp. (1.29%, CI: 0.35-3.26) followed by Leucocytozoon and Haemoproteus spp. CONCLUSIONS: The data generated in this study are the first of its type, which would be beneficial to the veterinary practice, aviculturists, pet bird owners and breeders in Bangladesh to respond appropriately for the prevention and control of the disease.

Frequently used therapeutic antimicrobials and their resistance patterns on Staphylococcus aureus and Escherichia coli in mastitis affected lactating cows.

Mastitis is one of the most frequent and costly production diseases of dairy cattle. It is frequently treated with broad-spectrum antimicrobials. The objectives of this work were to investigate the prevalence of Staphylococcus aureus and Escherichia coli, find out the antimicrobials used in mastitis treatment, and explore the antimicrobial resistance profile including detection of resistance genes. Bacterial species and antimicrobial resistance genes were confirmed by the polymerase-chain reaction. A total of 450 cows were screened, where 23 (5.11%) and 173 (38.44%) were affected with clinical and sub-clinical mastitis, respectively. The prevalence of S. aureus was 39.13% (n = 9) and 47.97%(n = 83) while, E. coli was 30.43% (n = 7) and 15.60% (n = 27) in clinical and sub-clinical mastitis affected cows, respectively. The highest antimicrobials used for mastitis treatment were ciprofloxacin (83.34%), amoxycillin (80%) and ceftriaxone (76.67%). More than, 70% of S. aureus showed resistance against ampicillin, oxacillin, and tetracycline and more than 60% of E. coli exhibited resistance against oxacillin and sulfamethoxazole-trimethoprim. Selected antimicrobial resistance genes (mecA, tetK, tetL, tetM, tetA, tetB, tetC, sul1, sul2 and sul3) were identified from S. aureus and E. coli. Surprisingly, 7 (7.61%) S. aureus carried the mecA gene and were confirmed as methicillin-resistant S. aureus (MRSA). The most prevalent resistance genes were tetK 18 (19.57%) and tetL 13 (14.13%) for S. aureus, whereas sul1 16 (47.06%), tetA 12 (35.29%), sul2 11 (32.35%) and tetB 7 (20.59%) were the most common resistance genes in E. coli. Indiscriminate use of antimicrobials and the presence of multidrug-resistant bacteria suggest a potential threat to public health.

Molecular detection of Toxoplasma gondii in aborted fetuses of goats in Chattogram, Bangladesh.

BACKGROUND AND AIM: Toxoplasma gondii is a protozoan parasite that is responsible for the major cause of congenital diseases, abortion, and stillbirth in humans and farm animals. Primary infection in pregnant goats due to T. gondii leads to abortion and significant economic losses in the livestock industry. Moreover, very few studies have been performed for the identification of T. gondii from aborted fetuses of goats. The study was conducted for the molecular identification of Toxoplasma gondii from aborted fetuses of goats in Chattogram, Bangladesh. MATERIALS AND METHODS: Twenty aborted fetuses of goats were collected from 52 farms in the study area. A nested polymerase chain reaction (PCR) assay targeting the B1 gene was performed, and a positive sample yield of 197 bp amplified DNA products consistent with T. gondii. RESULTS: The overall prevalence of toxoplasmosis in the aborted fetus of goats was 35%. Heart muscle, liver, brain, and placenta showed positive PCR results. The risk factors related to the does age, presence of cats in farms, and aborted fetus age were found to be statistically significant (p<0.05). Our results showed that T. gondii is a major possible causal factor for abortion and reproductive failure in goats. The high prevalence of T. gondii infection in aborted fetuses of goats revealed that T. gondii could be imperative in causing reproductive failure in goats. CONCLUSION: Active or congenital toxoplasmosis was shown by the presence of T. gondii in fetal tissues, which is a matter of concern as this parasite has zoonotic significance and causes economic hazards to the livestock industry by causing various reproductive problems. Therefore, proper control measures and strategies are needed to reduce the rate of abortion in goats, ultimately saving the livestock industry.

An Experimental and Systematic Insight into the Temperature Sensitivity for a 0.15-µm Gate-Length HEMT Based on the GaN Technology.

Presently, growing attention is being given to the analysis of the impact of the ambient temperature on the GaN HEMT performance. The present article is aimed at investigating both DC and microwave characteristics of a GaN-based HEMT versus the ambient temperature using measured data, an equivalent-circuit model, and a sensitivity-based analysis. The tested device is a 0.15-µm ultra-short gate-length AlGaN/GaN HEMT with a gate width of 200 µm. The interdigitated layout of this device is based on four fingers, each with a length of 50 µm. The scattering parameters are measured from 45 MHz to 50 GHz with the ambient temperature varied from -40 °C to 150 °C. A systematic study of the temperature-dependent performance is carried out by means of a sensitivity-based analysis. The achieved findings show that by the heating the transistor, the DC and microwave performance are degraded, due to the degradation in the electron transport properties.

Lumpy skin disease outbreak in cattle population of Chattogram, Bangladesh.

BACKGROUND: Lumpy skin disease (LSD) is an important viral disease causing significant economic losses in commercial livestock production. In mid-2019, an outbreak of LSD has been reported in cattle population from different parts of Bangladesh including Chattogram division. A cross-sectional surveillance study was undertaken from August 2019 to December 2019 to investigate the prevalence and associated risk factors of LSD in cattle in Chattogram district. METHODS: A total of 3,327 cattle from 19 commercial farms were examined for the LSD specific skin lesions and associated risk factors. A total of 120 skin biopsies were collected from the suspected animal for the confirmation of the disease using molecular detection and histopathological examination. Partial genome sequencing and phylogenetic analyses were performed on selected viral isolates. RESULTS: The overall clinical prevalence of LSD in the study population was 10% (95% confidence interval [CI]: 9.4%-11%) where the highest farm level outbreak frequency was 63.33% (95% CI: 45.51%-78.13%) and the lowest 4.22% (95% CI: 3.39%-5.25%). Crossbred and female cattle showed a significantly higher prevalence of the disease compared to their counterparts. Introduction of new animals in farms was found to be one of the most significant risk factors in the transmission of the disease. All suspected skin biopsies were positive for LSD virus (LSDV) infection with granulomatous and pyogranulomatous dermatitis was revealed on histopathology. Phylogenetic analysis based on the inverted terminal repeat region of the LSDV gene suggested that the locally circulating strain was closely related to the strains isolated from the Middle East and North African countries. CONCLUSIONS: The data generated in this study would be beneficial to the field veterinarians and animal health decision makers in the country as well as it will aid in taking appropriate measures to prevent further relapse or outbreak of this disease in future.

Mesoporous Carbon: A Versatile Material for Scientific Applications.

Mesoporous carbon is a promising material having multiple applications. It can act as a catalytic support and can be used in energy storage devices. Moreover, mesoporous carbon controls body's oral drug delivery system and adsorb poisonous metal from water and various other molecules from an aqueous solution. The accuracy and improved activity of the carbon materials depend on some parameters. The recent breakthrough in the synthesis of mesoporous carbon, with high surface area, large pore-volume, and good thermostability, improves its activity manifold in performing functions. Considering the promising application of mesoporous carbon, it should be broadly illustrated in the literature. This review summarizes the potential application of mesoporous carbon in many scientific disciplines. Moreover, the outlook for further improvement of mesoporous carbon has been demonstrated in detail. Hopefully, it would act as a reference guidebook for researchers about the putative application of mesoporous carbon in multidimensional fields.

Increased susceptibility to Mycobacterium tuberculosis infection in a diet-induced murine model of type 2 diabetes.

Tuberculosis (TB)-type 2 diabetes mellitus (T2D) comorbidity is re-emerging as a global public health problem. T2D is a major risk factor for increased susceptibility to TB infection and reactivation leading to higher morbidity and mortality. The pathophysiological mechanisms of T2D contributing to TB susceptibility are not fully understood, but likely involve dysregulated immune responses. In this study, a diet-induced murine model that reflects the cardinal features of human T2D was used to assess the immune responses following an intravenous Mycobacterium tuberculosis (Mtb) infection. In this study, T2D significantly increased mortality, organ bacillary burden and inflammatory lesions compared to non-diabetic controls. Organ-specific pro-inflammatory cytokine responses were dysregulated as early as one day post-infection in T2D mice. Macrophages derived from T2D mice showed reduced bacterial internalization and killing capacity. An early impairment of antimycobacterial functions of macrophages in diabetes is a key mechanism that leads to increased susceptibility of T2D.

Defect chemistry and defect engineering of TiO2-based semiconductors for solar energy conversion.

This tutorial review considers defect chemistry of TiO2 and its solid solutions as well as defect-related properties associated with solar-to-chemical energy conversion, such as Fermi level, bandgap, charge transport and surface active sites. Defect disorder is discussed in terms of defect reactions and the related charge compensation. Defect equilibria are used in derivation of defect diagrams showing the effect of oxygen activity and temperature on the concentration of both ionic and electronic defects. These defect diagrams may be used for imposition of desired semiconducting properties that are needed to maximize the performance of TiO2-based photoelectrodes for the generation of solar hydrogen fuel using photo electrochemical cells (PECs) and photocatalysts for water purification. The performance of the TiO2-based semiconductors is considered in terms of the key performance-related properties (KPPs) that are defect related. It is shown that defect engineering may be applied for optimization of the KPPs in order to achieve optimum performance.

Epidemiological and molecular analyses of a non-seasonal outbreak of acute icteric hepatitis E in Bangladesh.

Acute hepatitis due to hepatitis E virus (HEV) is endemic in Bangladesh, but its epidemiological characteristics and virological features remain obscure. An outbreak of acute icteric hepatitis E occurred in Rajshahi, Bangladesh during 2010 when 200 patients with visible jaundice visited physicians within a period of 1 month (January-February). Clinical and epidemiological data were collected from these patients using questionnaires. Nucleic acids were isolated from 15 patients who were selected at random to ascertain their HEV genotypes. Near-complete nucleotide sequences of the HEV genome were detected in two patients and partial ORF2 regions in the other 13 patients. All patients tested positive for IgM antibodies to HEV but negative for other hepatitis viruses. Most patients were icteric and complained of vomiting, fever, itching, and abdominal pain. All 15 HEV sequences formed a single cluster within genotype 1a. Two of the 7,186-nt HEV sequences were 99.8% identical. This is the first study to report the clinical, epidemiological, and molecular characterization of an outbreak of acute hepatitis E in Bangladesh.