Effect of Y substitution on the structural and magnetic properties of Dy1-xYxCo5 compounds

Structural and magnetization studies were carried out on Dy1-xYxCo5 [x = 0, 0.2, 0.4, 0.6, 0.8, 1] compounds which crystallize in the hexagonal CaCu5-type structure. Lattice parameters and unit-cell volume increase with Y concentration. Large thermomagnetic irreversibility between the field-cooled and the zero-field cooled magnetization data has been observed in all the compounds, which has been attributed to the domain wall pinning effect. Temperature dependence of magnetization data shows that except DyCo5 and YCo5, all the compounds show spin reorientation transitions in the range of 5-300 K. The spin reorientation temperature decreases from 266 K for x=0.2 to 100 K for x=0.8. Powder x-ray diffractograms of the magnetically aligned samples show that DyCo5 has planar anisotropy at room temperature whereas all the other compounds possess axial anisotropy. The spin reorientation transition has been attributed to a change in the easy magnetization direction from the ab-plane to the c-axis, as the temperature is increased. The anisotropy field and the first order anisotropy constant are found to be quite high in all the compounds except DyCo5. The magnetic properties have been explained by taking into account the variations in contributions arising from the rare earth and transition metal sublattices.Comment: 12 pages, 7 figure

The detection, outcome and molecular biology of pre-invasive lesions of the bronchus

Introduction: It is proposed that squamous cell carcinoma of the bronchus develops from carcinogen-exposed epithelium through a series of pre-invasive lesions of increasing histological and cytological abnormality. This has not been reliably demonstrated, and it is not known whether pre-invasive lesion development follows a predictable time-course and pattern or whether all pre-invasive lesions are committed to the development of malignancy. Pre-invasive lesions manifest genetic changes similar in pattern to that of squamous cell carcinoma. The accumulation of genetic damage, as a consequence of prolonged carcinogen exposure, may drive the progression of an individual pre-invasive lesion to malignancy, and the ultimate pattern of genetic changes may determine the outcome of that lesion. Methods: In the present work patients with pre-invasive lesions underwent serial bronchoscopy and biopsy to determine the natural history of pre-invasive lesions. Serial biopsies from lesions under follow-up were studied histologically and using loss of heterozygosity analysis at chromosomal loci thought to be involved in the pathogenesis of squamous cell carcinoma. Results: The natural history of pre-invasive lesions is variable. Some lesions progress, some regress and some remain unchanged histologically. Different lesions in a single patient may have different natural histories and different outcomes. Short-term follow-up may misrepresent the long-term evolution of an individual lesion or bronchoscopic location. Molecular studies showed that different lesions in individual patients appeared to have originated from a single progenitor cell, but acquired significant genetic differences during lesion development. Progression of pre-invasive lesions to carcinoma was associated with loss of heterozygosity along the majority of 3p with loss at 9p and the acquisition of 4p16 loss at the transition from carcinoma-in-situ to invasive disease. Regression to normal epithelium was associated with the failure to acquire these changes at the same time

An automated thermal-relaxation calorimeter for operation at low temperature (0.5 K <T <10 K)

The authors describe an automated calorimeter for measurement of the sp. heats at 10 > T > 0.5 K. It uses sample of moderate size (100-1000 mg), has a moderate precision and accuracy (2%-5%), is easy to operate and the measurements can be done quickly with He4. The accuracy of this calorimeter was checked by measurement of sp. heat of copper and that of aluminum near its superconducting transition temp. [on SciFinder (R)

ProTox-II: a webserver for the prediction of toxicity of chemicals

Advancement in the field of computational research has made it possible for the in silico methods to offer significant benefits to both regulatory needs and requirements for risk assessments, and pharmaceutical industry to assess the safety profile of a chemical. Here, we present ProTox-II that incorporates molecular similarity, pharmacophores, fragment propensities and machine-learning models for the prediction of various toxicity endpoints; such as acute toxicity, hepatotoxicity, cytotoxicity, carcinogenicity, mutagenicity, immunotoxicity, adverse outcomes pathways (Tox21) and toxicity targets. The predictive models are built on data from both in vitro assays (e.g. Tox21 assays, Ames bacterial mutation assays, hepG2 cytotoxicity assays, Immunotoxicity assays) and in vivo cases (e.g. carcinogenicity, hepatotoxicity). The models have been validated on independent external sets and have shown strong performance. ProTox-II provides a freely available webserver for in silico toxicity prediction for toxicologists, regulatory agencies, computational and medicinal chemists, and all users without login at http://tox.charite.de/protox_II. The webserver takes a two-dimensional chemical structure as an input and reports the possible toxicity profile of the chemical for 33 models with confidence scores, and an overall toxicity radar chart along with three most similar compounds with known acute toxicity

Chemical extraction and optimization of intracellular β-galactosidase production from the bacterium Arthrobacter oxydans using Box-Behnken design of response surface methodology

Present study demonstrated the isolation of most promising β-galactosidase producing bacterial strain SB from soil. Morphological, biochemical, and 16s rRNA sequence analysis identified the bacterial strain as Arthrobacter oxydans. Several chemicals, including SDS, Triton X-100, Tween 20, isoamyl alcohol, and toluene-acetone mixture, were applied for extraction of intracellular β-galactosidase from the bacterial strain Arthrobacter oxydans. Among these, Tween 20 was recorded to be most effective. Role of pH, temperature, and shaker speed on production of β-galactosidase was evaluated using Box-Behnken design of response surface methodology. According to Box-Behnken analysis, optimum production of β-galactosidase (21.38 U (mg–1 protein)) is predicted at pH 6.76, temperature 36.1 °C, and shaker speed 121.37 r.p.m. The parameters are validated with the nearest value

Disordered Type-II Superconductors: A Universal Phase Diagram for Low-Tc_c Systems

A universal phase diagram for weakly pinned low-T$_c$ type-II superconductors is revisited and extended with new proposals. The low-temperature ``Bragg glass'' phase is argued to transform first into a disordered, glassy phase upon heating. This glassy phase, a continuation of the high-field equilibrium vortex glass phase, then melts at higher temperatures into a liquid. This proposal provides an explanation for the anomalies observed in the peak effect regime of 2H-NbSe$_2$ and several other low-T$_c$ materials which is independent of the microscopic mechanisms of superconductivity in these systems.Comment: 23 pages, 9 figure

Geometric Phase: a Diagnostic Tool for Entanglement

Using a kinematic approach we show that the non-adiabatic, non-cyclic, geometric phase corresponding to the radiation emitted by a three level cascade system provides a sensitive diagnostic tool for determining the entanglement properties of the two modes of radiation. The nonunitary, noncyclic path in the state space may be realized through the same control parameters which control the purity/mixedness and entanglement. We show analytically that the geometric phase is related to concurrence in certain region of the parameter space. We further show that the rate of change of the geometric phase reveals its resilience to fluctuations only for pure Bell type states. Lastly, the derivative of the geometric phase carries information on both purity/mixedness and entanglement/separability.Comment: 13 pages 6 figure

Antimicrobial Activity of Cuminum cyminum L.

El comino (Cuminum cyminum) es un ingrediente habitual en la comida india. Ha sido usado desde hace mucho tiempo en la medicina tradicional para curar la diarrea, dispepsia y trastornos gástricos, así como agente antiséptico. Estudios realizados en nuestro laboratorio han mostrado que el comino tiene una potente actividad antimicrobiana sobre diversas especies de bacterias y hongos, tanto patógenas como no patógenas. Los estudios químicos realizados indican que la mayor parte de esta actividad antimicrobiana es debida al cuminaldehido [p-isopropil benzaldehido] presente en el fruto desecado de esta planta. Los estudios de concentración mínima inhibitoria (CMI) con el cuminaldehido aislado (comparado con el cuminaldehido patrón) indican que es efectivo sobre diferentes microorganismos, incluyendo cepas de bacterias, levaduras y hongos.Cumin (Cuminum cyminum) is a widely used ingredient in Indian food. It has been used for a very long time in traditional medicine in the treatment of diarrhoea, dyspepsia and gastric disorders, and as an antiseptic agent. Studies carried out at our laboratory have shown that cumin has powerful antimicrobial properties against diverse species of bacteria and fungi, as much in the case of pathogens as in non-pathogens. The chemical studies carried out indicate that the greater part of this antimicrobial activity may be attributed to the cuminaldehyde [p-isopropil benzaldehyde] that is present in the dried fruit of this plant. Minimum inhibitory concentration studies (MIC) with isolated cuminaldehyde (compared with standard cuminaldehyde) indicate that it is effective upon different microorganisms, including bacterial strains, yeasts and fungi