Possible Superconductivity at 37 K in Graphite-Sulfur Composite

Sulfur intercalated graphite composites with diamagnetic transitions at 6.7 K and 37 K are prepared. The magnetization hysteresis loops (MHL), Xray diffraction patterns, and resistance were measured. From the MHL, a slight superconducting like penetration process is observed at 15 K in low field region. The XRD shows no big difference from the mixture of graphite and sulfur indicating that the volume of the superconducting phase (if any) is very small. The temperature dependence of resistance shows a typical semiconducting behavior with a saturation in low temperature region. This saturation is either induced by the de-localization of conducting electrons or by possible superconductivity in this system.Comment: CHIN. PHYS.LETT v18 1648 (2001

De Haas - van Alphen Effect under Rotation

We explored the interplay between magnetic field and rotation in the de Hass - van Alphen oscillation. The effect is found to be reduced because of the re-weighting of different states within the same Landau level by rotation energy. The implications of our results on high energy physics and condensed matter physics are speculated.Comment: 21 pages, 9 figures in Revte

[N,N′-Bis(4-chloro­benz­yl)ethane-1,2-diamine]dichloridozinc(II)

In the title complex, [ZnCl2(C16H18Cl2N2)], the asymmetric unit contains one mol­ecule and two half-mol­ecules, which have similar geometric parameters; in the latter two molecules each Zn atom lies on a twofold rotation axis. The environment about each ZnII atom is distorted tetra­hedral with coordination of two terminal Cl atoms and two N atoms of the N,N′-bis­(4-chloro­benz­yl)ethane-1,2-diamine ligand. Four N—H⋯Cl hydrogen bonds link the mol­ecules into a chain of R 2 2(8) rings in the [001] direction

Voltammetric Behavior of o-Nitrophenol and Damage to DNA

The electrochemical behavior of o-nitrophenol was studied in detail with a glassy carbon electrode (GCE). The dependence of peak potential on pH indicated that equivalent electrons and protons were involved in the process of o-nitrophenol reduction. The interaction of o-nitrophenol with calf thymus DNA was investigated by adding DNA to the o-nitrophenol solution and by immobilizing DNA on GCE, respectively. The peak current decrement and peak potential shift in presence of DNA indicated that o-nitrophenol could interact with DNA. The result was demonstrated that the in situ DNA damage was detected by differential pulse voltammetry after the o-nitrophenol was electrochemically reduced

Dissolution rate enhancement of repaglinide by solid dispersion

Purpose: To enhance the solubility and dissolution rate of the antidiabetic drug repaglinide by solid dispersion (SD) techniqueMethod: The solid dispersion of repaglinide was prepared by solvent evaporation method using the hydrophilic carrier,  polyethylene glycol 4000 (PEG 4000) in three drug:PEG 4000 ratios (1:1, 1:3, 1:5). For comparison, physical mixtures of repaglinide and PEG 4000 in the same ratios were also prepared. The formulations were characterized by Fourier transformed infrared spectroscopy (FTIR), x-ray diffractometry (XRD) and differential scanning colorimetry (DSC). Phase solubility study of pure repaglinide, physical mixture and solid dispersion was performed in distilled water. Dissolution studies were carried out in pH 7.4 phosphate buffer.Results: DSC and XRD results indicate that repaglinide exists in amorphous form in solid dispersion. FT-IR analysis demonstrated the presence of intermolecular hydrogen bonding between repaglinide and PEG 4000 in the solid dispersion. The solubility of pure repaglinide was enhanced from 22.5± 5.0 to 235.5± 5.0 μg/mL in distilled water at 37 0C. Rapid burst release (80 - 86 %) from the solid dispersion formulations was observed within 15 min.Conclusion: The solubility and dissolution rate of repaglinide are enhanced by formulating SDs of repaglinide with PEG 4000. This will likely lead to increase in bioavailability which would be beneficial for better glucose control in diabetic patients.Keywords: Diabetes, Solid dispersion, Repaglinide, Solubility, Dissolution, Burst releas

Bis{6,6′-dimeth­oxy-2,2′-[ethane-1,2-diyl­bis(imino­methyl­ene)]diphenolato(1.5−)-κ4 O,N,N′,O′}praeseodymium(III)

The title compound, [Pr(C18H22.5N2O4)2], is isotypic with its Er and Tb analogues. All interatomic distances, angles and the hydrogen bond geometry are very similar for the three structures.

Bis{6,6′-dimeth­oxy-2,2′-[ethane-1,2-diyl­bis(imino­methyl­ene)]diphenolato(1.5−)-κ4 O,N,N′,O′}terbium(III)

The title compound, [Tb(C18H22.5N2O4)2], is isotypic with its Pr and Tb analogues. All interatomic distances, angles and the hydrogen bond geometry are very similar for the three structures

2-Chloro-N′-(2-hy­droxy-3,5-diiodo­benzyl­idene)benzohydrazide

In the title compound, C14H9ClI2N2O2, the dihedral angle between the benzene rings is 65.9 (2)° and an intra­molecular O—H⋯N hydrogen bond generates an S(6) ring. The mol­ecule has an E conformation about the C=N bond. In the crystal, mol­ecules are linked into C(4) chains propagating in [001] by N—H⋯O hydrogen bonds

A Novel Co-polymer Based on Hydroxypropyl α-Cyclodextrin Conjugated to Low Molecular Weight Polyethylenimine as an in Vitro Gene Delivery Vector

A novel co-polymer based on 2-hydroxypropyl-α-cyclodextrin cross-linked by low molecular weight polyethylenimine was synthesized as a gene delivery vector. The copolymer could bind and condense DNA tightly. It showed lower cytotoxicity than PEI 25kDa in SK-BR-3 cells. Transfection efficiency was increased over 5.5-fold higher than PEI 25 kDa in SK-BR-3 cells in complete serum medium. It is a potential candidate vector for gene therapy