Optimization of the Length of Silicon Nanowires Prepared from MACE Method Using Gene Expression Programming and Genetic Algorithm

Silicon - Metal-assisted chemical etching (MACE) of silicon is used in this study to fabricate silicon nanowire arrays (SiNWs) of different length. This method was modeled using gene expression...     

Conversion of CO into CO2 by high active and stable PdNi nanoparticles supported on a metal-organic framework

The solubility of Pd(NO₃)₂ in water is moderate whereas it is completely soluble in diluted HNO₃ solution. Pd/MIL-101(Cr) and Pd/MIL-101-NH₂(Cr) were synthesized by aqueous solution of Pd(NO₃)₂ and Pd(NO₃)₂ solution in dilute HNO₃ and used for CO oxidation reaction. The catalysts synthesized with Pd(NO₃)₂ solution in dilute HNO₃ showed lower activity. The aqueous solution of Pd(NO₃)₂ was used for synthesis of mono-metal Ni, Pd and bimetallic PdNi nanoparticles with various molar ratios supported on MOF. Pd₇₀Ni₃₀/MIL-101(Cr) catalyst showed higher activity than monometallic counterparts and Pd+ Ni physical mixture due to the strong synergistic effect of PdNi nanoparticles, high distribution of PdNi nanoparticles, and lower dissociation and desorption barriers. Comparison of the catalysts synthesized by MIL-101(Cr) and MIL-101-NH₂(Cr) as the supports of metals showed that Pd/MIL-101-NH₂(Cr) outperforms Pd/MIL-101-(Cr) because of the higher electron density of Pd resulting from the electron donor ability of the NH₂ functional group. However, the same activities were observed for Pd₇₀Ni₃₀/MIL-101(Cr) and Pd₇₀Ni₃₀/MIL-101-NH₂(Cr), which is due to a less uniform distribution of Pd nanoparticles in Pd₇₀Ni₃₀/MIL-101-NH₂(Cr) originated from amorphization of MIL-101-NH₂(Cr) structure during the reduction process. In contrast, Pd₇₀Ni₃₀/MIL-101(Cr) revealed the stable structure and activity during reduction and CO oxidation for a long time.     

Household biomass fuel use is associated with chronic childhood malnutrition: Result from a nationwide cross-sectional survey in Bangladesh

Despite significant investment, childhood malnutrition continues to be a significant public health problem especially in least developed countries. The aim of this study was to find association between household biomass fuel (BMF) use and childhood malnutrition in Bangladesh using data from Demographic and Health Survey 2011. We included a total 6891 children under 5 years of age in the analysis. The prevalence of wasting, underweight, and stunting from BMF using household was 16.1% (n = 997; 95%CI, 15.1–17.3), 39.0% (n = 2399; 95%CI, 37.1–40.9), and 43.3% (n = 2620; 95%CI, 41.6–45.1), respectively. Underweight and stunting were significantly higher among children from households using BMF compared with the children from CF using households (underweight, biomass vs clean fuel: 39.0% vs. 23.5%, p < 0.001; stunting, biomass vs clean fuel: 43.3 vs. 31.5%, p < 0.001). The use of BMF in the household was significantly associated with underweight (OR = 1.38; 95%CI: 1.10–1.73) and stunting (OR = 1.58; 95%CI: 1.18–1.98) among children <5 years of age after adjusting possible confounders in mixed effect logistic regression analysis. This study found a significant association between chronic childhood malnutrition and household BMF use which is indicating possible alternative risk factor for malnutrition. Further prospective research is required to explore the mechanism of how BMF use results in chronic malnutrition.     

Recent Advances in Ferroelectric-Enhanced Low-Dimensional Optoelectronic Devices

Ferroelectric (FE) materials, including BiFeO₃, P(VDF-TrFE), and CuInP₂S₆, are a type of dielectric material with a unique, spontaneous electric polarization that can be reversed by applying an external electric field. The combination of FE and low-dimensional materials produces synergies, sparking significant research interest in solar cells, photodetectors (PDs), nonvolatile memory, and so on. The fundamental aspects of FE materials, including the origin of FE polarization, extrinsic FE materials, and FE polarization quantification are first discussed. Next, the state-of-the-art of FE-based optoelectronic devices is focused. How FE materials affect the energy band of channel materials and how device structures influence PD performance are also summarized. Finally, the future directions of this rapidly growing field are discussed.     

Simultaneous determination of ultra trace amounts of lead and cadmium in food samples by adsorptive stripping voltammetry

A selective and sensitive method for simultaneous determination of lead and cadmium by adsorptive differential pulse cathodic stripping voltammetry is presented. The method is based on adsorptive accumulation of the complexes of Pb (II) and Cd (II) ions with 2-mercaptobenzothiazole onto hanging mercury drop electrode (HMDE), followed by the reduction of the adsorbed species by differential pulse cathodic stripping voltammetry. Optimal conditions were obtained at pH 8.0, 2-mercaptobenzothiazole concentration of 1.0 × 10⁻⁴ M, the accumulation potential of −0.4 V (vs. Ag/AgCl), the accumulation time of 160 s, and the scan rate of 100 mV/s. Under optimised conditions, linear calibration curves were established for the concentration of Pb (II) and Cd (II) in the range of 0.5–70 and 0.2–30 ng/ml, respectively, with detection limit of 0.017 ng/ml for Pb (II) and 0.01 ng/ml for Cd (II). The procedure was successfully applied to the simultaneous determination of both ions in food samples (rice, soya and sugar).