China Science

The purpose of the present study was to develop an optimized gastric floating drug delivery system (GFDDS) containing metoprolol tartrate (MT) as a model drug by the optimization technique. A 2[3] factorial design was employed in formulating the GFDDS with total polymer content-to-drug ratio (X1), polymer-to-polymer ratio (X2),; different viscosity grades of hydroxypropyl methyl cellulose (HPMC) (X3) as independent variables. Four dependent variables were considered: percentage of MT release at 8 hours, T50%, diffusion coefficient,; floating time. The main effect; interaction terms were quantitatively evaluated using a mathematical model. The results indicate that X1; X2 significantly affected the floating time; release properties, but the effect of different viscosity grades of HPMC (K4M; K10M) was nonsignificant. Regression analysis; numerical optimization were performed to identify the best formulation. Fickian release transport was confirmed as the release mechanism from the optimized formulation. The predicted values agreed well with the experimental values,; the results demonstrate the feasibility of the model in the development of GFDDS.

C. Narendra1Email:narendragcp@rediffmail.com?M. S. Srinath2?Ganesh Babu2
[1] Department of Pharmaceutics, Krupanidhi College of Pharmacy, Bangalore-34, India ;[2] Department of Pharmaceutics, Government College of Pharmacy, Bangalore-27, India ;[3] Department of Pharmaceutics, Visveswarapura Institute of Pharmaceutical Sciences, V.V. Puram, 560004 Bangalore, Karnataka, India

The orientation stability in equal channel angular extrusion (ECAE) of hexagonal close-packed (hcp) crystals using a 90° die is investigated based on the three-dimensional lattice rotation fields from rate-dependent crystal plasticity simulations. The results show that for the major slip and twinning modes considered, the relatively stable orientations in ECAE are distributed along the h1? to h6? fibers in the Euler space and feature characteristic alignments of the a- or c-axis with respect to the macroscopic deformation axes. The application of such simulations is demonstrated by comparing the predictions with experimental ECAE textures in high-purity titanium and other hcp polycrystalline materials, including commercial-purity zirconium, beryllium and magnesium alloys. The simulation results for ECAE are also applied to derive the relatively stable orientations in conventional simple shear deformation.

Saiyi LiaEmail:saiyi@scut.edu.cn
[a]School of Mechanical Engineering, South China University of Technology, Guangzhou 510640, China

Stability of crystallographic orientations is a key aspect in the characterization and understanding of texture evolution during plastic deformation. In this study, a rate-dependent crystal plasticity model was applied to investigate orientation stability during equal channel angular extrusion (ECAE) of face-centered cubic (fcc) and body-centered cubic (bcc) crystals. The stability of experimentally observed ideal orientations was examined according to lattice rotation fields computed at and around the orientations. It is shown that these ideal orientations are meta-stable under rate-sensitive conditions, and their stability generally increases with the decrease of strain rate sensitivity. The results also reveal a well-preserved duality in the lattice rotation and orientation stability between the two types of crystal structure. The stability results simulated at low strain rate sensitivities agree well with the experimental observations in one-pass ECAE of Al and Cu single crystals. In Part II of the paper, this analysis is extended to hexagonal materials.

Saiyi LiaEmail:saiyi@scut.edu.cn
[a]School of Mechanical Engineering, South China University of Technology, Guangzhou 510640, China

The diffuse scattering of body-centered cubic ?-Ti–V was measured using high-energy synchrotron X-rays and two-dimensional detectors. The study included in situ experiments of the equilibrium ?-phase and room temperature measurements of the quenched metastable state. The kinematical X-ray scattering revealed details in reciprocal space that could not be detected by the electron diffraction employed in previous studies. The signal was analyzed using a statistical thermodynamic approach based on physically motivated parameters. The characteristic features attributed to an ?-like structure or a “diffuse ?-phase” in the past are explained by static lattice distortions due to atomic size mismatch.

I.B. RamsteineraEmail:ramstein@seas.harvard.edu?O. Shchygloa?M. Mezgera?A. Udyanskya?V. Bugaeva?S. Schdera?H. Reicherta?H. Doscha
[a]Max-Planck-Institut für Metallforschung, Heisenbergstrasse 3, 70569 Stuttgart, Germany;[b]European Synchrotron Radiation Facility (ESRF), 38043 Grenoble, France

Methodological debates in accounting frequently emphasise the distinction between objective and subjective research. A growing body of interpretive management accounting studies, often based on fieldwork, is continuing to develop approaches that seek to overcome that distinction by exploring the various ways in which accounting can become part of the contexts in which it operates.

Thomas AhrensaEmail:Thomas.Ahrens@wbs.ac.uk
[a]Warwick Business School, University of Warwick, Coventry CV4 7AL, United Kingdom

New evidence has appeared to support the fact that the over-involvement of older drivers in traffic accidents disappears when the low mileage bias is taken into account. As a group, older drivers are as safe as or safer than other age groups, and only low mileage older drivers have a high crash rate. Furthermore, the role of the medical condition of older drivers in traffic accidents, as well as the fitness to drive evaluation, are objects of controversy. We examined all this with a cohort of 4316 drivers attending Medical Driving Test Centres for a mandatory fitness to drive evaluation. (more…)

OBJECTIVE: The Accreditation Council for Graduate Medical Education and the Residency Review Committee for psychiatry outline the expected competencies for residents. These competencies include working with families. (more…)

BACKGROUND: Rosai-Dorfman disease, or sinus histiocytosis with massivelymphadenopathy (SHML), is a rare, nonhereditary, benign histiocytic proliferative disorder,affecting mainly the lymph nodes. Orbital involvement in the absence of lymphadenopathy isrelatively uncommon. CASE: (more…)