Search

This study determines the prevailing concentrations of 222Rn in twenty groundwater samples and primordial radionuclides in twelve soil samples collected from the surrounding area of the Rooppur Nuclear Power Plant (RNPP) in Bangladesh. The mean concentration of 222Rn, 226Ra, 232Th and 40K in the studied samples was found to be 4.42 ± 2 Bq/L (Water), 25.2 ± 5.3, 23.9 ± 6.3 and 317.1 ± 31.4 Bq kg−1 (Soil) respectively. Associated health hazards were estimated and compared with the respective safety limits recommended by international organizations. The present results may serve as the base values of naturally occurring radioactive materials in the vicinity of the RNPP in Bangladesh. [ABSTRACT FROM AUTHOR]

Background: Non-alcoholic fatty liver disease (NAFLD) encompasses the simple steatosis to more progressive steatosis with associated hepatitis, fibrosis and cirrhosis. Though accurate diagnosis of simple fatty liver (SFL) and non-alcoholic steatohepatitis (NASH) can be made by liver biopsy, it is not feasible to be done in all NAFLD patients. Relationship of C-reactive protein (CRP) with NAFLD was well documented in many populations, but comprehensive data is lacking in Bangladeshi people. Method: This case-control study was conducted at the Medicine, Gastroenterology and Hepatology departments in Dhaka Medical College Hospital from March to August 2018 involving 30 patients with NAFLD as case and apparently healthy 30 individuals as control. Abdominal ultrasound to detect fatty liver and serum CRP level estimation by nephelometry were performed for each subject to compare between two groups. Result: Majority of the NAFLD cases and healthy controls were female (70% and 60% respectively). Mean age was 47.53±9.69 year in NAFLD group and 46.03±8.44 year in healthy controls. NAFLD cases had significantly higher mean serum CRP concentration (6.27±1.80) mg/dl than that of healthy controls (3.94±2.16) mg/dl (p<0.001). Overweight/obesity and dyslipidaemia were found as significant risk factors for NAFLD compared to the healthy control group (p<0.05). Conclusion: NAFLD cases had significantly higher CRP than the control group. But, to find out the association of increasing CRP level with the severity of NAFLD and to establish it as a diagnostic tool, further extensive studies are recommended. [ABSTRACT FROM AUTHOR]

The nanostructures synthesized using the green chemistry method have recently attracted the attention of scientists due to their significance in many scientific domains. This work provides an overview of the biosynthesis of zinc oxide (ZnO) nanosheets (NSs) using Phyllanthus emblica plant (PEP) extract. X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) were used to analyze the synthesized ZnO-NSs. Evaluation of the antibacterial activity of biosynthesized ZnO-NSs was performed. ZnO-NSs exhibit effective antibacterial activity against Gram-positive (S. pyogenes and S. aureus) and Gram-negative (S. typhi and E. coli) bacterial strains. S. typhi is the most sensitive microbe towards ZnO-NSs and formed a 21 mm zone of inhibition (ZOI). ZnO-NSs are also tested as a photocatalyst in the degradation of methyl orange (MO) and rhodamine B (RB). The degradation rate of MO was 90%, and RB was 96% after being exposed to UV light for 120 min. The as-synthesized ZnO-NSs exhibited selective dye degradation and showed relatively better photocatalytic activity for positively charged (cationic) dyes. This work could lead to the fabrication of high-yield photocatalysts, which have the potential to degrade textile dyes from aqueous solution. [ABSTRACT FROM AUTHOR]

Present work reports an elegant method to address the emergence of two Dirac cones in a non-hexagonal graphene allotrope S-graphene (SG). We have availed nearest neighbour tight binding (NNTB) model to validate the existence of two Dirac cones reported from density functional theory (DFT) computations. Besides, the real space renormalization group (RSRG) scheme clearly reveals the key reason behind the emergence of two Dirac cones associated with the given topology. Furthermore, the robustness of these Dirac cones has been explored in terms of hopping parameters. As an important note, the Fermi velocity of the SG system (vF ≃ c/80) is almost 3.75 times that of the graphene. It has been observed that the Dirac cones can be easily shifted along the symmetry lines without breaking the degeneracy. We have attained two different conditions based on the sole relations of hopping parameters and on-site energies to break the degeneracy. Further, in order to perceive the topological aspect of the system we have obtained the phase diagram and Chern number of Haldane model. This exact analytical method along with the supported DFT computation will be very effective in studying the intrinsic behaviour of the Dirac materials other than graphene. [ABSTRACT FROM AUTHOR]

In this work, density functional theory (DFT)-based calculations were performed to compute the physical properties (structural stability, mechanical behavior, and electronic, thermodynamic, and optical properties) of synthesized MAX phases Hf 2 SB, Hf 2 SC, Hf 2 SeB, Hf 2 SeC, and Hf 2 TeB and the as-yet-undiscovered MAX carbide phase Hf 2 TeC. Calculations of formation energy, phonon dispersion curves, and elastic constants confirmed the stability of the aforementioned compounds, including the predicted Hf 2 TeC. The obtained values of lattice parameters, elastic constants, and elastic moduli of Hf 2 SB, Hf 2 SC, Hf 2 SeB, Hf 2 SeC, and Hf 2 TeB showed fair agreement with earlier studies, whereas the values of the aforementioned parameters for the predicted Hf 2 TeC exhibit a good consequence of B replacement by C. The anisotropic mechanical properties are exhibited by the considered MAX phases. The metallic nature and its anisotropic behavior were revealed by the electronic band structure and density of states. The analysis of the thermal properties-Debye temperature, melting temperature, minimum thermal conductivity, and Grüneisen parameter-confirmed that the carbide phases were more suited than the boride phases considered herein. The MAX phase's response to incoming photons further demonstrated that they were metallic. Their suitability for use as coating materials to prevent solar heating was demonstrated by the reflectivity spectra. Additionally, this study demonstrated the impact of B replacing C in the MAX phases., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

In this article, ab initio calculations of unexplored Ti 2 PB 2 , Zr 2 PbB 2 , and Nb 2 AB 2 [A = P, S] were performed wherein Ti 2 PB 2 along with its 211 boride phase Ti 2 PB was predicted for the first time. The stability was confirmed by calculating the formation energy, phonon dispersion curve, and elastic stiffness constants. The obtained elastic constants, elastic moduli, and Vickers hardness values of Ti 2 PB 2 , Zr 2 PbB 2 , and Nb 2 AB 2 [A = P, S] were found to be significantly larger than those of their counterparts 211 borides and carbides. The studied compounds are brittle, like most MAX and MAB phases. The electronic band structure and density of states revealed the metallic nature of the titled borides. Several thermal parameters were explored, certifying the suitability of Ti 2 PB 2 , Zr 2 PbB 2 , and Nb 2 AB 2 [A = P, S] to be used as efficient thermal barrier coating materials. The response of Ti 2 PB 2 , Zr 2 PbB 2 , and Nb 2 AB 2 [A = P, S] to the incident photon was studied by computing the dielectric constant (real and imaginary parts), refractive index, absorption coefficient, photoconductivity, reflectivity, and energy loss function. In this work, we have explored the physical basis of the improved thermomechanical properties of 212 MAX phase borides compared to their existing carbide and boride counterparts., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Smallholder farmers in Bangladesh often use low-density polyethylene (LDPE) bags contained within woven polypropylene bags to store wheat seed during the summer monsoon that precedes winter season planting. High humidity and temperature during this period can encourage increased seed moisture and pests, thereby lowering seed quality. Following a farm household survey conducted to inform trial design, eighty farmers were engaged in an action research process in which they participated in designing and conducting trials comparing traditional and alternative seed storage methods over 30 weeks. Factorial treatments included comparison of hermetic SuperGrainbags® (Premium RZ) against LDPE bags, both with and without the addition of dried neem tree leaves ( Azadirachta indica ). SuperGrainbags® were more effective in maintaining seed moisture at acceptable levels close to pre-storage conditions than LDPE bags. Both seed germination and seedling coleoptile length were significantly greater in hermetic than LDPE bags. Neem had no effect on seed moisture, germination, or coleoptile length. SuperGrainbags® were also more effective in abating seed damage during storage, although inclusion of neem within LDPE bags also had significant damage. Quantification of seed predating insects and diseases suggested that SuperGrainbags® also suppressed Coleopteran pests and blackspot, the latter indicative of Fusarium graminearum . Conversely, where farmers used LDPE bags, neem also had an additional though limited pest suppressive effect. Post-storage treatment scoring by farmers revealed a strong preference for SuperGrainbags® and no preference differences for or against neem. This study demonstrates a process by which farmers can be involved in the participatory co-design and testing of alternative wheat storage options, and stresses the need to develop SuperGrainbag® supply chains so hermetic storage can be made widely available., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2022 The Authors.)

Boron-rich chalcogenides have been predicted to have excellent properties for optical and mechanical applications in recent times. In this regard, we report the electronic, optical, and mechanical properties of recently synthesized boron-rich chalcogenide compounds B 12 X (X = S and Se) using density functional theory for the first time. The effects of exchange and correlation functionals on these properties are also investigated. The consistency of the obtained crystal structure with the reported experimental results has been checked in terms of lattice parameters. The considered materials are mechanically stable, brittle, and elastically anisotropic. Furthermore, the elastic moduli and hardness parameters are calculated, which show that B 12 S can be treated as a prominent member of the hard materials family compared to B 12 Se. The origin of differences in hardness is explained on the basis of density of states near the Fermi level. Reasonably good values of fracture toughness and the machinability index for B 12 X (X = S and Se) are reported. The melting point, T m , for the B 12 S and B 12 Se compounds suggests that both solids are stable, at least up to 4208 and 3577 K, respectively. Indirect band gaps of B 12 S (2.27 eV) and B 12 Se (1.30 eV) are obtained using the HSE06 functional. The energy gaps using local density approximation (LDA) and generalized gradient approximation (GGA) are found to be significantly lower. The electrons of the B 12 Se compound show a lighter average effective mass than that of the B 12 S compound, which signifies a higher mobility of charge carriers in B 12 Se. The optical properties such as the dielectric function, refractive index, absorption coefficient, reflectivity, and loss function are characterized using GGA-PBE and HSE06 methods and discussed in detail. These compounds possess bulk optical anisotropy, and excellent absorption coefficients in the visible-light region along with very low static values of reflectivity spectra (range of 7.42-14.0% using both functionals) are noted. Such useful features of the compounds under investigation show promise for applications in optoelectronic and mechanical sectors., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)