Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants

High-resolution optical spectra of 57 Galactic B-type supergiant stars have been analysed to determine their rotational and macroturbulent velocities. In addition, their atmospheric parameters (effective temperature, surface gravity and microturbulent velocity) and surface nitrogen abundances have been estimated using a non-local thermodynamic equilibrium grid of model atmospheres. Comparisons of the projected rotational velocities have been made with the predictions of stellar evolutionary models and in general good agreement was found. However, for a small number of targets, their observed rotational velocities were significantly larger than predicted, although their nitrogen abundances were consistent with the rest of the sample. We conclude that binarity may have played a role in generating their large rotational velocities. No correlation was found between nitrogen abundances and the current projected rotational velocities. However, a correlation was found with the inferred projected rotational velocities of the main-sequence precursors of our supergiant sample. This correlation is again in agreement with the predictions of single star evolutionary models that incorporate rotational mixing. The origin of the macroturbulence and microturbulent velocity fields is discussed and our results support previous theoretical studies that link the former to subphotospheric convection and the latter to non-radial gravity mode oscillations. In addition, we have attempted to identify differential rotation in our most rapidly rotating targets.

Neural Network Modeling of Rheological Parameters of Grouts Containing Viscosity-Modifying Agent

The development of artificial neural network (ANN) models to predict the rheological behavior of grouts is described is this paper and the sensitivity of such parameters to the variation in mixture ingredients is also evaluated. The input parameters of the neural network were the mixture ingredients influencing the rheological behavior of grouts, namely the cement content, fly ash, ground-granulated blast-furnace slag, limestone powder, silica fume, water-binder ratio (w/b), high-range water-reducing admixture, and viscosity-modifying agent (welan gum). The six outputs of the ANN models were the mini-slump, the apparent viscosity at low shear, and the yield stress and plastic viscosity values of the Bingham and modified Bingham models, respectively. The model is based on a multi-layer feed-forward neural network. The details of the proposed ANN with its architecture, training, and validation are presented in this paper. A database of 186 mixtures from eight different studies was developed to train and test the ANN model. The effectiveness of the trained ANN model is evaluated by comparing its responses with the experimental data that were used in the training process. The results show that the ANN model can accurately predict the mini-slump, the apparent viscosity at low shear, the yield stress, and the plastic viscosity values of the Bingham and modified Bingham models of the pseudo-plastic grouts used in the training process. The results can also predict these properties of new mixtures within the practical range of the input variables used in the training with an absolute error of 2%, 0.5%, 8%, 4%, 2%, and 1.6%, respectively. The sensitivity of the ANN model showed that the trend data obtained by the models were in good agreement with the actual experimental results, demonstrating the effect of mixture ingredients on fluidity and the rheological parameters with both the Bingham and modified Bingham models.

Correlation of synovial fluid cytokine levels with histological and clinical parameters of primary and revision total hip and total knee replacements

We retrieved synovial tissue and fluid samples from patients undergoing primary total hip replacement (THR) (n 15), revision of aseptically loose THR (n 12), primary total knee replacement (TKR) (n 13) and revision of aseptically loose TKR (n 6). Several histological parameters were assessed on a relative scale of 1-4. Primary TJRs were clinically evaluated for degree of osteoarthrosis. Revision TJRs were assessed for migration of the implant, gross loosening and the degree of radiolucency. Cytokine levels in synovial fluid were determined with ELISA.

Dependence of the ion energy on the parameters of the laser pulse and target in the radiation-pressure-dominated regime of acceleration

When the dominant mechanism for ion acceleration is the laser radiation pressure, the conversion efficiency of the laser energy into the energy of relativistic ions may be very high. Stability analysis of a thin plasma layer accelerated by the radiation pressure shows that Raleigh-Taylor instability may enhance plasma inhomogeneity. In the linear stage of instability, the plasma layer decays into separate bunches, which are accelerated by the radiation pressure similarly to clusters accelerated under the action of an electromagnetic wave. The energy and luminosity of an ion beam accelerated in the radiation-pressure-dominated regime are calculated.

Runx2, p53, and pRB Status as Diagnostic Parameters for Deregulation of Osteoblast Growth and Differentiation in a New Pre-Chemotherapeutic Osteosarcoma Cell Line (OS1)

Osteosarcomas are the most prevalent primary bone tumors found in pediatric patients. To understand their molecular etiology, cell culture models are used to define disease mechanisms under controlled conditions. Many osteosarcoma cell lines (e.g., SAOS-2, U2OS, MG63) are derived from Caucasian patients. However, patients exhibit individual and ethnic differences in their responsiveness to irradiation and chemotherapy. This motivated the establishment of osteosarcoma cell lines (OS1, OS2, OS3) from three ethnically Chinese patients. OS1 cells, derived from a pre-chemotherapeutic tumor in the femur of a 6-year-old female, were examined for molecular markers characteristic for osteoblasts, stem cells, and cell cycle control by immunohistochemistry, reverse transcriptase-PCR, Western blotting and flow cytometry. OS I have aberrant G-banded karyotypes, possibly reflecting chromosomal abnormalities related to p53 deficiency. OS I had ossification profiles similar to human fetal osteoblasts rather than SAOS-2 which ossifies ab initio, (P

Physicochemical characterisation and drug release properties of celecoxib hot melt extruded glass solutions

Formulation of Celecoxib into solid dosage forms is difficult due to the physical properties of the drug powder. However for the first time, this paper reports on the drug delivery characteristics glass solutions of celecoxib and polyvinylpyrrolidone prepared by hot melt extrusion, together with use of supercritical carbon dioxide to achieve a porous structure, in order to achieve a stable and enhanced drug release.

Physicochemical Characterization of Hot Melt Extruded Bicalutamide–Polyvinylpyrrolidone Solid Dispersions

Solid molecular dispersions of bicalutamide (BL) and polyvinylpyrrolidone (PVP) were prepared by hot melt extrusion technology at drug-to-polymer ratios of 1:10, 2:10, and 3:10 (w/w). The solid-state properties of BL, physical mixtures of BL/PVP, and hot melt extrudates were characterized using differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD), Raman, and Fourier transform infrared (FTIR) spectroscopy. Drug dissolution studies were subsequently conducted on hot melt extruded solid dispersions and physical mixtures. All hot melt extrudates had a single Tg between theTg of amorphous BL and PVP indicating miscibility of BL with PVP and the formation of solid molecular dispersions. PXRD con?rmed the presence of the amorphous form of BL within the extrudates. Conversely, PXRD patterns recorded for physical mixtures showed sharp bands characteristic of crystalline BL, whereas DSC traces had a distinct endotherm at 1968C corresponding to melting of crystalline BL. Further investigations using DSC con?rmed solid-state plasticization of PVP by amorphous BL and hence antiplasticization of amorphous BL by PVP. Experimentally observed Tg values of physical mixtures were shown to be signi?cantly higher than those calculated using the Gordon–Taylor equation suggesting the formation of strong intermolecular interactions between BL and PVP. FTIR and Raman spectroscopy were used to investigate these interactions and strongly suggested the presence of secondary interaction between PVP and BL within the hot melt extrudates. The drug dissolution properties of hot melt extrudates were enhanced signi?cantly in comparison to crystalline BL and physical mixtures. Moreover, the rate and extent of BL release were highly dependent on the amount of PVP present within the extrudate. Storage of the extrudates con?rmed the stability of amorphous BL for up to 12 months at 208C, 40% RH whereas stability was reduced under highly humid conditions (208C, 65% RH). Interestingly, BL recrystallization after storage under these conditions had no effect on the dissolution properties of the extrudates.