Search results for " density"

First-principles calculations of the atomic and electronic structure of SrZrO3 and PbZrO3 (001) and (011) surfaces.

2010

We present the results of calculations of surface relaxations, rumplings, energetics, optical band gaps, and charge distribution for the SrZrO(3) and PbZrO(3) (001) and (011) surfaces using the ab initio code CRYSTAL and a hybrid description of exchange and correlation. We consider both SrO(PbO) and ZrO(2) terminations of the (001) surface and Sr(Pb), ZrO, and O terminations of the polar SrZrO(3) and PbZrO(3) (011) surfaces. On the (001) surfaces, we find that all upper and third layer atoms relax inward, while outward relaxations of all atoms in the second layer are found with the sole exception of the SrO-terminated SrZrO(3) (001) surface second layer O atom. Between all (001) and (011) s…

Morphologische Strukturen und Rißbildung in kristallinen, makromolekularen Stoffen

1962

Nach einem kurzen Uberblick uber die heutigen Kenntnisse der morphologischen Strukturen (Lamellen, Fibrillen und Spharolithe) werden die Versuche besprochen, und mit Hilfe von Permeations- und Diffusionsmessungen an Terylenfilmen in Abhangigkeit vom Kristallisationsgrade und der Temperatur einen Einblick in das innere Rissystem won makromolekularen Werkstoffen zu bekommen. Es zeigt sich, das man bei schonender thermischer und mechanischer Behandlung eine grobere durchgehende Risbildung u. entsprechende Korrosionsanfalligkeit durchaus vermeiden werden kann. Kristallisiert man zu lange bei zu hohen Temperaturen so tritt Risbildung auf. Hier kommen dann mikroskopische Untersuchungen sowie solc…

Charge-density analysis of 1-nitroindoline: refinement quality using free R factors and restraints. Corrigendum

2011

The D e (dissociation energy) values in Table 6 of the article by Zarychta et al. [(2011). Acta Cryst. B67, 250–262] are corrected.

Statistical Properties of Generalized Strain Criterion for Multiaxial Random Fatigue

1989

ABSTRACT Statistical properties of generalized criterion of the maximum shear and normal strains on the fracture plane have been presented, Functions of probability distribution and spectral density of the equivalent strain have been analysed on the assumption that a random tensor of strain state is a six-dimensional stationary and ergodic Gaussian process. The expected value and variance of the equivalent strain have been determined as well. From spectral analysis a new limitation has been derived for extension of some multiaxial cyclic fatigue criteria to random loadings. It is connected with the fact that in some cases the frequency band of the equivalent strain is greater than that for …

The role of cell interactions in the control of RNA synthesis.

1967

Spontaneous cytotoxic activity of eosinophilic granule cells separated from the normal peritoneal cavity ofDicentrarchus labrax

2000

Abstract In this study the spontaneous in vitro cytotoxic activity to tumour cell lines, (K562), by unstimulated sea bass ( Dicentrarchus labrax ) leukocytes was examined by trypan blue exclusion test and lactate dehydrogenase release assay. A high anti-tumour cell line activity of resident peritoneal leukocytes was found at an effector to target ratio (E:T) of 25:1 after incubation for 2 h at 18° C. Rabbit and sheep erythrocytes were not lysed. A low activity was displayed by head kidney and spleen cell populations whereas blood leukocytes revealed no significant activity. The effect of E:T ratio on cytotoxicity as well as microscopy observations suggested that the cytotoxic reaction requi…

Diffusion coefficient of PVA Fricke gel dosimeters

2015

Fricke gel dosimeters based on various matrix has been studied for a long time as 3D dosimetric system for radiotherapy. Selfoxidation and loss of spatial resolution due to diffusion have been the main issues that have impaired the affirmation of this technique so far. As part of an Italian nation-wide research program, we were interested in develop new gel formulations that are simple, reproducible and non toxic. We studied the one dimensional diffusion coefficient of Fe3+ ions inside Fricke gel dosimeters based on a matrix of PVA cross-linked with a di-aldehyde. With a spectrophotometer equipped with a moving tray we were able to collect absorbance measurements at different positions of t…

Quantification of bacterial subgroups in soil : comparison of DNA extracted directly from soil or from cells previously released by density gradient …

2001

All molecular analyses of soil bacterial diversity are based on the extraction of a representative fraction of cellular DNA. Methods of DNA extraction for this purpose are divided into two categories: those in which cells are lysed within the soil (direct extraction) and those in which cells are first removed from soil (cell extraction) and then lysed. The purpose of this study was to compare a method of direct extraction with a method in which cells were first separated from the soil matrix by Nycodenz gradient centrifugation in order to evaluate the effect of these different approaches on the analysis of the spectrum of diversity in a microbial community. We used a method based on polymer…

Digital image processing for rapid analysis of differentially expressed transcripts on high-density cDNA arrays.

1999

Usage of filter arrays is becoming increasingly attractive for many research laboratories involved in determination of gene-expression profiles. However, analysis of numerous spots, representing genes or partial gene sequences (ESTs), is still tedious work involving the ordered analysis of vast amounts of numerical tabular data. We present a rapid and efficient method for the visual identification of differentially expressed targets on high-density cDNA filter arrays using standard laboratory equipment and standard software, which is available for free. The method we introduce provides an inexpensive alternative, and no changes in the experimental set up are required. Our results were veri…

The Mediating Role of Endocrine Factors in the Positive Relationship Between Fat Mass and Bone Mineral Content in Children Aged 9-11 Years: The Physi…

2022

IntroductionWe aimed to investigate whether the relationship between fat mass and bone mineral content (BMC) is mediated by insulin, leptin, adiponectin, dehydroepiandrosterone sulphate, testosterone and estradiol in children aged 9-11 years.Materials and MethodsWe utilised cross-sectional data from the Physical Activity and Nutrition in Children study (n = 230 to 396; 112 to 203 girls). Fat mass and BMC were assessed with dual-energy X-ray absorptiometry. Endocrine factors were assessed from fasted blood samples. We applied the novel 4-way decomposition method to analyse associations between fat mass, endocrine factors, and BMC.ResultsFat mass was positively associated with BMC in girls (ß…