One‐Step Synthesis of SnO2 and TiO2 Hollow Nanostructures with Various Shapes and Their Enhanced Lithium Storage Properties

A versatile one‐step method for the general synthesis of metal oxide hollow nanostructures is demonstrated. This method involves the controlled deposition of metal oxides on shaped α‐Fe₂O₃ crystals which are simultaneously dissolved. A variety of uniform SnO₂ hollow nanostructures, such as nanococoons, nanoboxes, hollow nanorings, and nanospheres, can be readily generated. The method is also applicable to the synthesis of shaped TiO₂ hollow nanostructures. As a demonstration of the potential applications of these hollow nanostructures, the lithium storage capability of SnO₂ hollow structures is investigated. The results show that such derived SnO₂ hollow structures exhibit stable capacity retention of 600–700 mAh g^?1 for 50 cycles at a 0.2 C rate and good rate capability at 0.5–1 C, perhaps benefiting from the unique structural characteristics.     

Structural variations of nickel complexes in NiS4 and NiS2PN coordination environments: spectral and single-crystal X-ray structural studies on bis(4-methylpiperidinecarbodithioato-S,S′)nickel(II) and (4-methylpiperidinecarbodithioato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II)

Abstract  

[Ni(4-mpipdtc)₂] and [Ni(4-mpipdtc)(PPh₃)(NCS)] (4-mpipdtc = 4-methylpiperidinecarbodithioate anion) have been characterized by electronic, IR, and NMR spectroscopy, single crystal X-ray analysis, and cyclic voltammetry. IR spectra of the complexes show the contribution of the thioureide form to the structures. ¹H NMR spectra show the deshielding of α-CH₂ protons on complexation. ¹³C NMR spectra shows interesting differences between the N¹³CS₂ carbon signals of the parent complex [Ni(4-mpipdtc)₂] and the mixed ligand complex [Ni(4-mpipdtc)(PPh₃)(NCS)]. The N¹³CS₂ carbon signal for [Ni(4-mpipdtc)(PPh₃)(NCS)] is observed at 204.85 ppm with an upfield shift of about 3.8 ppm compared with that found in [Ni(4-mpipdtc)₂] (201.06 ppm). The observed shielding in [Ni(4-mpipdtc)(PPh₃)(NCS)] indicates the effect of PPh₃ on the mesomeric drift of electron density toward nickel through the thioureide C–N bond. Single crystal X-ray analysis of [Ni(4-mpipdtc)₂] and [Ni(4-mpipdtc)(PPh₃)(NCS)] confirms the presence of four-coordinated nickel in a distorted square-planar arrangement with the NiS₄ and NiS₂PN chromophores, respectively. The C–N (thioureide) bond lengths of [Ni(4-mpipdtc)(PPh₃)(NCS)] are shorter than those found in [Ni(4-mpipdtc)₂], because of the presence of the π-acid (triphenylphosphine) in [Ni(4-mpipdtc)(PPh₃)(NCS)]. Significant asymmetry in Ni–S bond distances was observed in Ni(4-mpipdtc)(PPh₃)(NCS)] (2.162(2) and 2.211(2) ?). This observation clearly supports the less effective trans effect of SCN^– over PPh₃. The piperidine ring in the dithiocarbamate fragment is in the normal chair conformation.     

HPTLC analysis of Scoparia dulcis Linn (Scrophulariaceae) and its larvicidal potential against dengue vector Aedes aegypti

This study evaluates the larvicidal activity of Scoparia dulcis aqueous extract against dengue vector and determines its major chemical components. The extract was tested at various concentrations ranging from 0.1 to 2 mg/mL against Aedes aegypti larvae. The extracts displayed significant larvicidal efficacy against Ae. aegypt species after 24 h exposure revealing LC₅₀ of 3.3835 (mg/mL) and LC₉₀ of 5.7578 (mg/mL). Finger printing profile carried out by CAMAG automatic TLC sample applicator programmed through WIN CATS software revealed peaks with different R_f values for three different volumes injected: 16, 15 and 18 peaks were spotted for 3, 6 and 9 μL, respectively. Ascending order of R_f values was also ascertained for each peak recorded. This study clearly signifies that S. dulcis extract contains numerous compounds that are known to have larvicidal properties which clearly substantiates its efficacy on Ae. aegypti larvae.     

Mass–yield distributions of fission products from photo-fission of natPb induced by 50–70 MeV bremsstrahlung

The mass–yield distributions of various fission products have been determined in the 50-, 60- and 70-MeV end point bremsstrahlung induced fission of ^natPb using off-line γ-ray spectrometric technique in the electron linac at Pohang Accelerator Laboratory, Korea. The mass–yield distributions are symmetric with average mass of 102.34, 102.25 and 102.03 and FWHM of 21, 22 and 23 mass unit, respectively. From the present data and literature data in the 50–85 MeV bremsstrahlung induced fission of ²⁰⁹Bi the following observations were obtained: (i) The average masses of the yield distributions in the 50–85 MeV bremsstrahlung induced fission of ^natPb and ²⁰⁹Bi are around 102.25 ± 0.25 and 103 ± 0.5, respectively. (ii) The FWHM of the mass–yield distributions increases from about 21 mass units at 50 MeV to 23 mass units at 70–85 MeV, which is explained from the point of increase in multi-chance fission probability with increasing excitation energy. (iii) Within the bremsstrahlung energy range of 50–85 MeV, the role of nuclear structure effect in the mass–yield distribution was observed in the photo-fission of ²⁰⁹Bi, whereas it was not seen in case of ^natPb. This may be due to the presence of so many isotopes in ^natPb unlike mono-isotopic ²⁰⁹Bi.     

Impact of Targeted Specific Antibiotic Delivery for Gut Microbiota Modulation on High-Fructose-Fed Rats

The objective of present investigation was to study the effect of gut microbiota alteration by oral administration of targeted delivery of pH sensitive cefdinir microspheres to high-fructose-fed (HFD) rats. Rats were fed with a high-fructose diet with or without cefdinir microsphere administration for 30 days. The fecal microbiota community, oral glucose tolerance, the markers of liver injury, plasma and hepatic lipids profile, and histological evaluation were investigated. The levels of blood glucose, liver injury markers, lipid profile in plasma and liver, and fat tissue were significantly increased in high-fructose-fed rats. However, after pH-sensitive cefdinir microsphere administration, the elevation of these parameters was significantly suppressed. Cef EL significantly lowered the increased AST (p?<?0.05) and ALT (p?<?0.001) levels in HFD group. There is a significant lower (p?<?0.01) AUC_glucose level in Cef EL group than HFD group The histological changes in the liver and the small and large intestines were more profound in HFD group as compared to cefdinir-treated HFD and control groups. Feeding of cefdinir microsphere sustained lactobacilli and bifidobacteria and significantly decreased (p?<?0.05) the number of Enterobacteriaceae induced by HFD. Experimental evidences demonstrated that the effectiveness of pH-specific cefdinir microsphere on reducing insulin resistance and development of metabolic changes in high-fructose-fed rats and suggested that it may be a promising therapeutic agent in treating type 2 diabetes. Intestinal-targeted antibiotic delivery needs to be further explored for its therapeutic applications.