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Tantalum (Ta) has excellent prospects in the bone-implant field due to its satisfactory biocompatibility. Two novel Ta lattice structures were designed and printed by selective laser melting (SLM), including the imitation saddle surface (ISS) and the imitation arch bridge telescopic (IABT) structures. Quasi-static compression tests and finite element analysis were adopted to investigate the effects of design parameters on the mechanical properties, deformation modes, and energy absorption of lattice structures. Compared with the typical lattice structure body-centred cubic (BCC) structure, the ISS lattice structure had a higher yield-stress-to-elastic-modulus ratio, and the IABT lattice structure had higher energy absorption. The failure mode of the BCC and ISS lattice structures was shear band formation. The IABT lattice structure showed hierarchical deformation during compression and collapsed with vertical strut buckling. The results indicated that the ISS lattice is the most potential candidate for bone implant applications. [ABSTRACT FROM AUTHOR]

We propose using greedy and randomized Kaczmarz inner-iterations as preconditioners for the right-preconditioned flexible GMRES method to solve consistent linear systems, with a parameter tuning strategy for adjusting the number of inner iterations and the relaxation parameter. We also present theoretical justifications of the right-preconditioned flexible GMRES for solving consistent linear systems. Numerical experiments on overdetermined and underdetermined linear systems show that the proposed method is superior to the GMRES method preconditioned by NE-SOR inner iterations in terms of total CPU time. [ABSTRACT FROM AUTHOR]

Cell division cycle 42 (CDC42), which is a member of the Rho GTPase family, has been reported to regulate the metastasis of various human cancer cells; however, the role of CDC42 in gastric cancer (GC) remains unclear. The present study aimed to investigate the effects of CDC42 on the proliferation, migration and invasion of GC. Furthermore, the molecular mechanisms underlying the effects of CDC42 on GC were explored. The expression levels of CDC42 in the AGS and SGC7901 human GC cell lines were reduced by RNA interference. Knockdown of CDC42 significantly inhibited the proliferation of AGS and SGC7901 cells, and it was suggested that this inhibitory process may be due to cell cycle arrest at G1/S phase and downregulation of cyclin A, cyclin D1, cyclin E and proliferating cell nuclear antigen. Furthermore, knockdown of CDC42 markedly inhibited the migration and invasion of GC cells, and suppressed the expression of matrix metalloproteinase 9. These results indicated that CDC42 is a key regulator involved in regulating the proliferation, migration and invasion of GC, and it may be considered a potential therapeutic target in GC. [ABSTRACT FROM AUTHOR]

When introduced into the infarcted heart, bone marrow.derived mesenchymal stem cells (MSCs) prevent the heart from deleterious remodeling and improve its recovery. The aim of the present study was to investigate the effects of Ginkgo biloba extract (EGb) 761 on the infarcted myocardium microenvironment following MSC transplantation. The established rat myocardial infarction (MI) model, with implanted PKH.26 marked MSCs (1x105 cells), were randomly divided into two groups: The control group (injected with normal saline) and the EGb 761 treatment group (injected with 100 mg/kg/day EGb 761). The following indices for cardiac function, including the extent of inflammation, oxidative stress, MSC apoptosis and MSC differentiation were measured 1, 2 and 7 days after treatment. The anti.inflammatory effect of EGb 761 was observed by histological examination. Compared with the respective control group, the malondialdehyde content significantly decreased and the superoxide dismutase, catalase and glutathione peroxidase activity significantly increased in the EGb761.treated groups. In addition, the apoptotic index gradually decreased (P<0.05) with the extension of MI time in the EGb761-treated groups compared to the respective control groups, suggesting that EGb761 exhbits anti-oxidative effects. In addition, the level of the Fas protein was positively correlated with the implanted MSC apoptotic ratio. Following 7 days of MSC transplantation with EGb 761 treatment, the expression of cTnI in PKH26.labeled MSCs was observed in the transplanted myocardium. Cardiac function, including the ejection fraction, left ventricular end.systolic pressure and dp/dtmax significantly increased, and the left ventricular end diastolic diameters, left ventricular end.diastolic volumes and left ventricular end.diastolic pressure significantly decreased (P<0.05, vs. the control group). The results demonstrated that EGb 761 is important in improving cardiac function and the infarcted myocardium microenvironment. The present study indicated that the protective effects of EGb 761 on the infarcted myocardium may be mediated by improving the viability and the differentiation of the implanted MSCs into cardiomyocytes. [ABSTRACT FROM AUTHOR]

A new broadband circularly polarized (CP) square slot antenna with coplanar waveguide fed is proposed. Two symmetrical E-shaped slits embedded in opposite corners of ground plane are designed to obtain an excellent CP bandwidth. Simulated results show that the broadband performance is formed by three resonant modes. Some key parameters are studied to analysis the characteristics of the proposed antenna. Measured results show that the 3 dB axial ratio bandwidth is larger than 32.8% relative to the center frequency of 2165 MHz and the impedance bandwidth is as large as 54.8% with voltage standing wave ratio (VSWR) ≤2. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 409–412, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24904 [ABSTRACT FROM AUTHOR]

The thermodynamic mixing properties of the pyrope-grossular solid solution show large deviations from ideality, which could be partly related to Ca-Mg order/disorder. In this study, synthetic pyrope-grossular garnets with XMg = 1.00, 0.91, 0.75, 0.50, 0.24, 0.10, and 0.00 are observed using 17O 3QMAS, 27Al MAS, and 29Si MAS NMR to examine Ca-Mg order/disorder behavior and crystal chemical variations. The 17O 3QMAS NMR spectra show four distinct resonances, assigned to four different local oxygen coordination environments; two resemble end-member garnets (oxygen bonded to two Mg or two Ca) and two are intermediate (oxygen bonded to one Ca and one Mg), indicating that there are two distinct bond distances for the Mg-O and/or Ca-O bonds through the entire solid solution. Noticeable changes in the NMR peak position for two of the oxygen sites suggest that as XMg increases, the longer Ca-O bond shortens. The relative areas for the different oxygen sites are close to those predicted using a model of random Ca/Mg mixing. The maximum allowed reduction in configurational entropy from first neighbor Ca-Mg ordering is insignificant relative to other configurational entropy reductions and excess vibrational entropy. These conclusions are not inconsistent with published theoretical calculations suggesting some Ca-Mg ordering that involves correlations beyond the first neighbor, as suggested by published theoretical calculations. Even at 18.8 Tesla, the 27Al MAS NMR spectra do not resolve different local Al sites with varying combinations of X cation neighbors. The 29Si MAS NMR spectra have resonance broadening, probably caused by the addition of 0.15 wt% Fe2O3 in the synthetic samples, and are consistent with published results suggesting a small degree of Ca-Mg ordering that is not reflected in the 17O NMR spectra. [ABSTRACT FROM AUTHOR]

Describes simulation and analytical models for the ultrasonic, sonic drill, corer (USDC). Use of a novel drive mechanism which transfers ultrasonic vibrations of a piezoelectric actuator into larger oscillations at a free-flying mass; Development of a simplified integrated model to simulate the operation of the USDC; Interactions of the main parts of the device.

Presents a study that investigated the disordering of silicon and aluminum in natrolite, scolecite, mesolite and gonnardite with magic angle spinning nuclear magnetic resonance spectroscopy. Methodology; Results; Discussion.

Presents the first solid-state [sup35]chlorine (Cl) nuclear magnetic resonance data (NMR) for Cl in silicate and aluminosilicate glasses. Analysis of NMR data; Examination of chemical shift systematics of [sup35]Cl; Analysis of coordination of chloride ions in silicate glasses.

Analyzes whether or not Vitamin E could attenuate oxidative stress for the preservation of renal function and structure in an aging rat. Association of the aging of kidney with the reduction in glomerular filtration rate; Induction of heme oxygenase in the degradation of heme; Oxidative stress and lipid peroxidation as aging related changes of rat kidney.