Exploring half-metallic ferromagnetism and thermoelectric properties of Tl2WX6 (X = Cl and Br) double perovskites.

Half-metallic semiconductors typically exhibit 100% spin polarization at the Fermi level which makes them desired materials for spintronic applications. In this study, we reported a half-metallic ferromagnetic nature in vacancy-ordered double perovskites Tl2WX6 (X = Cl and Br). The magnetic, electronic, and thermoelectric properties of the material are studied by the use of density functional theory (DFT). For the calculations of exchange-correlation potential, PBE-sol is employed while more accurate electronic band structure and density of states (DOS) are calculated by the mBJ potential. Both materials exhibited structural stability in the cubic structure with Fm3̄m space-group. The mechanical stability is confirmed by their computed elastic constants while their thermodynamic stability is attested by negative formation energy. The spin-based volume optimization suggested the ferromagnetic nature of the materials which is further confirmed by the negative value of the exchange energy Δ x(pd). Moreover, computed magnetic moment value for Tl2WCl6 and Tl2WBr6 is 2 µB and the majority of this comes from W. The spin-polarized band structure and DOS confirmed that both materials are half-metallic and at the Fermi level they exhibit 100% spin polarization. Furthermore, in the spin-down state, materials behave as semiconductors with wide bandgaps. Lastly, the thermoelectric properties are evaluated by the BoltzTrap code. The thermoelectric parameters which include the Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and figure of merit (ZT) are investigated in the range of temperatures from 200 to 800 K. The half-metallic ferromagnetic and thermoelectric characteristics make these materials desired for spintronics and thermoelectric applications.

Investigation of half metallic properties of Tl2Mo(Cl/Br)6 double perovskites for spintronic devices.

The manipulation of electronic device characteristics through electron spin represents a burgeoning frontier in technological advancement. Investigation of magnetic and transport attributes of the Tl2Mo(Cl/Br)6 double perovskite was performed using Wien2k and BoltzTraP code. When the energy states between ferromagnetic and antiferromagnetic conditions are compared, it is evident that the ferromagnetic state exhibits lower energy levels. Overcoming stability challenges within the ferromagnetic state is achieved through the manipulation of negative ΔHf within the cubic state. The analysis of the half metallicity character involves an analysis of band structure (BS) and DOS, elucidating its mechanism through PDOS using double exchange model p-d hybridization. The verification of 100% spin polarization is confirmed through factors such as spin polarization and the integer value of the total magnetic moment. Furthermore, the thermoelectric response, as indicated by the ratios of thermal-electrical conductivity and ZT, underscores the promising applications of these compounds in thermoelectric device applications.

The cytotoxicity effect of bismuth oxide particles synthesized hydrothermally using different reaction temperatures in vitro.

INTRODUCTION: Bismuth oxide (Bi2O3) particles gained attention in preclinical research especially in medical imaging. Bismuth oxide with its long circulation time is an alternative to the current iodine contrast media which directly possesses high X-ray attenuation coefficient. Exploration of bismuth compound is hampered owing to challenges in synthesizing control for in vivo stability. MATERIALS AND METHODS: This study aimed are to characterize Bi2O3 particles synthesized at 60, 90 and 120 °C via hydrothermal method and investigated cytotoxicity of cell viability assay, cell morphology analysis, intracellular reactive oxygen species (ROS) assay and expression of ER stress genes by real-time PCR. RESULTS: Results indicated that the size of rod-shaped Bi2O3 particles increased with rising synthesizing temperatures. The cytotoxicity of Bi2O3 particles in Chang liver cells was size-dependent. Bigger-sized Bi2O3 particles resulted in lesser toxicity effects. mRNA expressions of GRP78 and C/EBP homologous protein (CHOP) were down-regulated in all treated Chang liver cells due to the increasing size of Bi2O3 particles. Bi2O3 particles synthesized at 120 °C was found to be less toxic than iodine. CONCLUSION: Data suggested that the response of Chang liver cells to Bi2O3 particle cytotoxicity has a significant relationship with its reaction temperatures. This outcome is important in hazard assessment of Bi2O3 particles as a new contrast media and provides better understanding in synthesizing control to enhance its biocompatibility.

From tap to table: An assessment of drinking water quality in Perak, Malaysia.

INTRODUCTION: A study on the quality of drinking water was conducted at Air Kuning Treatment Plant In Perak, Malaysia, based on a sanitary survey in 14 sampling points stations from the intake area to the auxiliary points. This was to ensure the continuous supply of clean and safe drinking water to the consumers for public health protection. The objective was to examine the physical, microbiological, and chemical parameters of the water, classification at each site based on National Drinking Water Standards (NDWQS) and to understand the spatial variation using environmetric technique; principal component analysis (PCA). MATERIALS AND METHODS: Water samples were subjected to in situ and laboratory water quality analyses and focused on pH, turbidity, chlorine, Escherichia coli, total coliform, total hardness, iron (Fe), aluminium (Al), zinc (Zn), magnesium (Mg) and sodium (Na). All procedures followed the American Public Health Association (APHA) testing procedures. RESULTS: Based on the results obtained, the values of each parameter were found to be within the safe limits set by the NDWQS except for total coliform and iron (Fe). PCA has indicated that turbidity, total coliform, E. coli, Na, and Al were the major factors that contributed to the drinking water contamination in river water intake. CONCLUSION: Overall, the water from all sampling point stations after undergoing water treatment process was found to be safe as drinking water. It is important to evaluate the drinking water quality of the treatment plant to ensure that consumers have access to safe and clean drinking water as well as community awareness on drinking water quality is essential to promote public health and environmental protection.

Physical properties of ferromagnetic Mn-doped double perovskites (DPs) Cs2AgInCl/Br6 for spintronics and solar cell devices: DFT calculations.

A computational framework based on density functional theory (DFT) has been effectively employed to investigate the wide-ranging physical characteristics of ferromagnetic manganese (Mn)-substituted double perovskites (DPs) with composition Cs2AgIn1-xMnxCl/Br6 (x = 0.0, 0.25). This research covers a systematic exploration of the mentioned DPs for potential applications in the domains of spintronics and energy conversion devices. The physics concerning ferromagnetic (FM) Cs2AgIn0.75Mn0.25Cl/Br6 DPs was studied computationally using the modified Becke-Johnson (mBJ-LDA) potential and the generalized gradient approximation (PBEsol GGA) method introduced by Perdew, Burke, and Ernzerhof. The structural, electronic, magnetic, and transport behavior of materials were investigated using these computations. Structural parameters for both perovskite materials were computed subsequent to their optimization in FM phase. According to evaluations of the electronic band structure and density of states (DOS), the incorporation of Mn ions into the host lattice causes exchange splitting induced by p-d hybridization, consequently stabilizing the FM state. Probing the sharing of magnetic moment, charge, and spin between the substituent cations and the host anions led to the comprehensive elaboration of this exchange splitting of bands. Important parameters such as exchange constants (N0α, N0ß), and direct spin-exchange splitting Δx(d), support the stability of the FM state. Finally, we briefly explored the spin effect on other aspects of electronic transport, the Seebeck coefficient, and the power factor, using the conventional Boltzmann transport theory.

Physical properties of vacancy-ordered double perovskites K2TcZ6 (Z = Cl, Br) for spintronics applications: DFT calculations.

Vacancy-ordered double perovskites (DPs) are emerging materials for spintronics due to their stable structures and non-toxic properties. In this study, we conducted a comprehensive investigation into the role of 4d electrons in Tc to understand their impact on the ferromagnetic properties of K2TcY6 (Y = Cl, Br). We have employed a modified Back and Johnson potential to assess electronic and magnetic characteristics and utilized the BoltzTraP code to investigate thermoelectric effects. Experimental lattice constants confirmed the presence of stable structures and formation energy estimates affirmed their thermodynamic stability. The Heisenberg model and density of electron states (DOS) at the Fermi level provides insights into Curie temperature and spin polarization. The presence of ferromagnetism is evident in the density of states, reflecting the transition of electron spins that support the exchange mechanism. The study delves into how electron functionality influences the control of ferromagnetism, considering exchange constants, exchange energies, hybridization process and the crystal field energies. Moreover, the exploitation of magnetic moments from Tc to K and Cl/Br sites takes precedence in driving ferromagnetism by exchanging electron spins rather than forming magnetic clusters. Additionally, to explore the optical characteristics of the compounds, we investigated their optical absorption, dielectric constants and refractive index within the energy range of 0-10 eV, ensuring absorption across both the visible and ultraviolet regions. Finally, we delve into the impact of the thermoelectric effect on both thermoelectric performance and spin functionality, taking into account factors such as the Seebeck coefficient, power factor, and electronic conductivity.

First principles investigation of halide based Rb2NaGaZ6 (Z = Br, I) double perovskites for energy harvesting applications.

Extensive investigations have been conducted on the thermoelectric and optoelectronic characteristics of double perovskite compounds using the full potential linearized augmented plane wave (FP-LAPW) approach. Here we investigated Rb2NaGaZ6 (Z = Br, I) to explore its band structure, and electronic, optical and transport properties. Born's stability criteria have confirmed the mechanical stability of these compounds. Analysis of the elastic properties reveals their ductile nature, as indicated by a Poisson coefficient (υ) greater than 0.26 and a Pugh ratio exceeding 1.75 for Rb2NaGaZ6 (Z = Br, I). Computation of the bandgap values shows that both compositions possess a direct bandgap nature, with respective values of 2.90 eV and 1.25 eV. This suggests that substituting Br with I brings the band edges closer together, resulting in a decrease in the bandgap value. The optical properties are assessed based on the absorption coefficient, reflectivity, and dielectric constants. The thermoelectric properties, including thermal and electrical conductivities, power factor (PF), and figure of merit (ZT), are determined using the BoltzTrap code. The ZT values indicate that both compositions exhibit promising potential for various transportation applications.

Preoperative Neutrophil-to-Lymphocyte Ratio Plus Platelet-to-Lymphocyte Ratio Predicts the Outcomes after Curative Resection for Hepatocellular Carcinoma.

BACKGROUND: In recent years, inflammation-based scoring systems have been reported to predict survival in Hepatocellular Carcinoma (HCC). The aim of our study was to validate combined preoperative Neutrophil-to-Lymphocyte ratio (NLR)-Platelet-to-Lymphocyte ratio (PLR) in predicting overall survival (OS) and recurrence free survival (RFS) in patients who underwent curative resection for HCC. METHODS: We conducted a retrospective study of HCC patients underwent liver resection with curative intent from January 2010 to December 2013. Receiver-operating characteristic (ROC) curve analysis was used to determine the optimal cut-off values for NLR and PLR. Patients with both NLR and PLR elevated were allocated a score of 2; patients showing one or neither of these indices elevated were accorded a score of 1 or 0, respectively. RESULTS: 132 patients with a median age of 66 years (range 18-87) underwent curative resection for HCC. Overall morbidity was 30.3%, 30-day mortality was 2.3%, and 90-day mortality was 6.8%. At a median follow-up of 24 months (range 1-88), 25% patients died, and 40.9% had recurrence. On multivariate analysis, elevated preoperative NLR-PLR was predictive of both OS (HR 2.496; CI 1.156-5.389; p=0.020) and RFS (HR 1.917; CI 1.161-3.166; p=0.011). The 5-year OS was 76% for NLR-PLR=0 group, 21.7% for the NLR-PLR=1 group, and 61.1% for the NLR-PLR=2 group, respectively. The 5-year RFS was 39.3% for the NLR-PLR=0 group, 18.4% for the NLR-PLR=1 group, and 21.1% for the NLR-PLR=2 group, respectively. CONCLUSION: The preoperative NLR-PLR is predictive of both OS and RFS in patients with HCC undergoing curative liver resection.

Opto-electronic and thermoelectric properties of MgIn2X4 (X = S, Se) spinels via ab-initio calculations.

The structural behavior of MgIn2X4 (X = S, Se) has been elaborated by FP-LAPW + lo method as included in the Wien2k code. The stability of the phase has been confirmed by negative formation energy (-1.24 eV for MgIn2S4 and -0.78 eV for MgIn2Se4). The band gap dependent opto-electronic and thermoelectric properties are realized by modified Becke-Johnson exchange potential. The electronic band gap tuned from ultraviolet to visible (3.1 eV and 1.9 eV) by replacing the S with Se that motivated the studied spinels for photovoltaic and solar applications. Moreover, the attenuation of light, dispersion, transparency, reflection and energy loss when light scattered from material are discussed as function of energy. The thermal conductivity to electrical conductivity ratio, potential gradient and thermal efficiency in the range 0.78-0.80 are elaborated. The comparative study of opto-electronic and thermoelectric properties for energy harvesting increases the potential for optoelectronic than thermoelectric applications.

Physical properties of cubic BaGeO3 perovskite at various pressure using first-principle calculations for energy renewable devices.

The electronic, optical and thermoelectric analyses of BaGeO3 perovskite have been done by using density functional theory (DFT) based Trans and Blaha modified Becke and Johnson (TB-mBJ) approach. The applied pressure (up to 30 GPa) has been found tailoring the band gap from indirect to direct bandgap (at 20 GPa), within the visible region, revealing renewable energy applications of the studied perovskite. The applied pressure improves mechanical stability by increasing ductility. Furthermore, optical properties are illustrated by computing dielectric constants, refraction, absorption, optical conductivity and optical loss factor for suggesting optoelectronic applications. The maximum peaks shifting to higher energy, due to increasing pressure indicate a blue shift. Finally, the calculated thermal and electrical conductivities, See-beck coefficient, power factor, Hall coefficient, specific heat capacity, susceptibility and electron densities are also elaborated for thermoelectric applications by using BoltzTraP code.

Systematic study of room-temperature ferromagnetism and the optical response of Zn1-x TM x S/Se (TM = Mn, Fe, Co, Ni) ferromagnets: first-principle approach.

The structural, magnetic and optical characteristics of Zn1-x TM x S/Se (TM = Mn, Fe, Co, Ni and x = 6.25%) have been investigated through the full-potential linearized augmented plane wave method within the framework of density functional theory. The optimized structures have been used to calculate the ferromagnetic and the antiferromagnetic ground-state energies. The stability of the ferromagnetic phase has been confirmed from the formation and the cohesive energies. The Heisenberg model is used to elucidate the Curie temperature (T c) of these alloys. From the band structures and density of states plots, it has been observed that TM-doped ZnS/Se alloys appear to be semiconductors and exhibit ferromagnetism. In addition, the observed ferromagnetism has also been explained in terms of direct exchange energy Δ x (d), exchange splitting energy Δ x (pd), crystal-field energy (E crys), exchange constants (N 0 α and N 0 ß) and magnetic moments that shows potential spintronic applications. The optical behaviors of these alloys have been explained in terms of real and imaginary parts of the dielectric constant ε(ω), refractive index n(ω), extinction coefficient K(ω), reflectivity R(ω) and absorption coefficient σ(ω), in the energy range 0-25 eV. The calculated static limits of the band gaps and real part of the dielectric constants satisfy the Penn model. The critical limits of the imaginary part of the dielectric constants and absorption coefficients indicate that these alloys can be operated in the visible and the ultraviolet region of the electromagnetic spectrum; therefore, make them important for optoelectronic applications.

Variations in amino acid neurotransmitters in some brain areas of adult and young male albino rats due to exposure to mobile phone radiation.

BACKGROUND AND OBJECTIVES: Mobile phone radiation and health concerns have been raised, especially following the enormous increase in the use of wireless mobile telephony throughout the world. The present study aims to investigate the effect of one hour daily exposure to electromagnetic radiation (EMR) with frequency of 900 Mz (SAR 1.165 w/kg, power density 0.02 mW/cm2) on the levels of amino acid neurotransmitters in the midbrain, cerebellum and medulla of adult and young male albino rats. MATERIALS AND METHODS: Adult and young rats were divided into two main groups (treated and control). The treated group of both adult and young rats was exposed to EMR for 1 hour daily. The other group of both adult and young animals was served as control. The determination of amino acid levels was carried out after 1 hour, 1 month, 2 months and 4 months of EMR exposure as well as after stopping radiation. RESULTS: Data of the present study showed a significant increase in both excitatory and inhibitory amino acids in the cerebellum of adult and young rats and midbrain of adult animals after 1 hour of EMR exposure. In the midbrain of adult animals, there was a significant increase in glycine level after 1 month followed by significant increase in GABA after 4 months. Young rats showed significant decreases in the midbrain excitatory amino acids. In the medulla, the equilibrium ratio percent (ER%) calculations showed a state of neurochemical inhibition after 4 months in case of adult animals, whereas in young animals, the neurochemical inhibitory state was observed after 1 month of exposure due to significant decrease in glutamate and aspartate levels. This state was converted to excitation after 4 months due to the increase in glutamate level. CONCLUSION: The present changes in amino acid concentrations may underlie the reported adverse effects of using mobile phones.

First Report of Glomerella cingulata (Colletotrichum gloeosporioides) Causing Anthracnose and Tip Dieback of Lygodium microphyllum and L. japonicum in Australia.

The Old World climbing fern, Lygodium microphyllum (Cav.) R. Br., and Japanese climbing fern, L. japonicum (Thunb.) Sw., are invasive noxious weeds in Florida (1). Exploratory surveys for classical biological control agents of L. microphyllum in the fern's native range of Australia and Asia have focused on aboveground herbivores (1). From February to August 2006, fungi were isolated from symptomatic foliage, including lesions associated with leaf curls caused by the mite Flocarus perrepae Knihinicki & Boczek., obtained from L. microphyllum at sites across southeast Queensland, Australia and from both fern species grown at the CSIRO Long Pocket Laboratories in Brisbane, Australia. Anthracnose symptoms with chlorotic margins, initiating at the tip or base of the individual pinnules, were observed on fronds. Dieback symptoms affected growing tips, with sunken lesions and a gradual necrotic wilt as far as the next growth junction of pinnae. Sections from diseased margins were surface sterilized, placed onto water agar, and incubated at 23°C with a 16-h photoperiod. Variable colonies of white-to-gray mycelia, felted or tufted with complete margins, grew well on oatmeal agar and potato dextrose agar. Conidia were hyaline to light salmon, aseptate, straight, and cylindrical (10.4 to 18.2 × 2.6 to 5.2 µm), borne in salmon-to-bright orange masses at 25°C, and consistent with previous descriptions of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (3), anamorph of Glomerella cingulata (2). Asci that formed after 3 to 4 weeks in culture were eight-spored, clavate to cylindrical (46.8 to 62.4 × 9.1 to 11.7 µm), and thickened at the apex, and ascospores were cylindrical (11.7 to 18.2 × 3.9 to 5.2 µm), slightly curved, unicellular and hyaline, which is consistent with descriptions of G. cingulata (2). No fruiting bodies were observed in planta; acervuli, setae, and perethecia were not observed. Identification was further confirmed by molecular analysis using the primer pair ITS1/ITS4 (4) (GenBank Accession No. EU697014), indicating 100% similarity to isolates of G. cingulata. To confirm pathogenicity, Koch's postulates were performed on three plants of L. japonicum and 12 plants of L. microphyllum, with an equal number of controls. Conidial suspensions were made to 1.7 × 106 conidia ml-1. During the experiments in the glasshouse, temperatures ranged from 12.6 to 40°C and relative humidity from 39 to 85%. Tips and fronds were collected after 2 to 8 weeks and isolation and identification performed. G. cingulata was consistently reisolated from diseased tissue. No symptoms appeared on controls and isolations did not yield the pathogen. To our knowledge, this is the first report of G. cingulata infecting L. microphyllum and L. japonicum in Australia. Its potential as a biological control agent in the ferns' introduced range remains to be tested. References: (1) J. A. Goolsby et al. Biol. Control. 28:33, 2003. (2) J. E. M. Mordue. Glomerella cingulata. No. 315 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CAB, Kew, UK, 1971. (3) B. C. Sutton. The Genus Glomerella and its Anamorph Colletotrichum. In: Colletotrichum: Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, UK, 1992. (4) T. M. White et al. Amplification and Direct Sequencing of Fungal Ribosomal RNA for Phylogenetics. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.