Ameliorative effect of α‐tocopherol on monosodium glutamate‐induced cardiac histological alterations and oxidative stress

BACKGROUND: Chronic oral intake of high doses of monosodium glutamate (MSG) causes oxidative stress. Oxidative stress plays an important role in the development of cardiac dysfunction and injury. Supplementation with α‐tocopherol protects the body against oxidative stress and its related complications. This study was proposed to examine the protective effect of α‐tocopherol against MSG‐induced biochemical and histological alterations in blood and cardiac tissue of rats for a period of 180 days. RESULTS: Chronic oral administration of MSG (4 g kg^?1) caused oxidative stress that was manifested by significant increase (P < 0.05) in malondialdehyde, conjugated dienes and by the decrease in the activities of superoxide dismutase, catalase, reduced glutathione, glutathione peroxidase and glutathione S‐transferase in cardiac tissue. The significantly increased (P < 0.05) activities of aspartate transaminase, creatine phosphokinase and lactate dehydrogenase in serum suggested a cardiac functional disorder. Moreover, heart muscle fibers showed cloudy swelling, fiber separation and vascular congestion. Administration of α‐tocopherol (200 mg kg^?1) significantly (P < 0.05) attenuated the MSG‐induced biochemical alterations in serum and cardiac tissue. α‐Tocopherol also prevented the pathological changes in cardiac tissue when compared with the MSG‐treated group. CONCLUSION: Our findings suggest that α‐tocopherol may have a protective effect against MSG‐induced cardiotoxicity, possibly through its antioxidant activity. Copyright © 2012 Society of Chemical Industry     

Compact wideband antenna for 2.4 GHz WLAN applications

A novel compact wideband antenna for wireless local area network (WLAN) applications in the 2.4 GHz band is presented. The proposed low profile antenna of dimensions 15/spl times/14.5/spl times/1.6 mm offers 18.6% bandwidth and an average gain of /spl sim/5 dBi. The antenna can be excited directly using a 50 /spl Omega/ coaxial probe.     

A compact dual band planar branched monopole antenna for DCS/2.4-GHz WLAN applications

A compact dual band planar antenna for a digital communication system (DCS)/2.4-GHz WLAN application is presented. The two resonant modes of the proposed antenna are associated with various length of the monopoles, in which a longer arm contributes for the lower resonant frequency and a shorter arm for higher resonant frequency. The experimental results show that the designed antenna can provide excellent performance for DCS/2.4-GHz WLAN systems, including sufficiently wide frequency band, moderate gain, and nearly omnidirectional radiation coverage. The outcome of the experimental results along with the design criteria are presented in this letter.     

Compact dual-band antenna for wireless access point

A compact dual-band printed antenna covering the 2.4 GHz (2400-2485 MHz) and 5.2 GHz (5150-5350 MHz) WLAN bands is presented. The experimental analysis shows a 2:1 VSWR bandwidth of up to 32 and 8% for 2.4 and 5.2 GHz, respectively. The measured radiation patterns are nearly omnidirectional, with moderate gain in both the WLAN bands.     

Tissue-engineered triphasic ceramic coated hydroxyapatite induced bone formation and vascularization at an extraskeletal site in a rat model

Tissue-engineered bone regeneration has attracted much attention because of its high clinical demand for restoration of injured tissues. In the present study, we have evaluated the capability of bare (without cells) and tissue-engineered (with osteogenic-induced rat Mesenchymal Stem Cells (MSCs)) bioactive ceramics such as hydroxyapatite (HA) and triphasic ceramic-coated hydroxyapatite (HASi) to mediate vascularisation and osteoinduction at an extraskeletal site of rat model. The viability, proliferation and osteogenic differentiation of MSCs on the scaffolds were assessed in vitro and thereby established the capability of HASi in providing a better structural habitat than HA. The vascular invasion was relatively low in bare and tissue-engineered HA at 2 and 4 weeks. Interestingly, the implantation site was well vascularised with profuse ingrowth of blood capillaries in HASi groups, with preference for tissue-engineered HASi groups. Similarly, neo-osteogenesis studies were shown only by tissue-engineered HASi groups. The ingrowth of numerous osteoblast-like cells was seen around and within the pores of the material in bare HASi and tissue-engineered HASi groups (very low cellular infiltration in bare HA groups), but there was no osteoid deposition. The positive impact in forming bone in tissue-engineered HASi groups is attributable to the scaffold and to the cells, with the first choice for scaffold because both HA and HASi were engineered simultaneously with the cells from same source and same passage. Thus, highly porous interconnected porous structure and appropriate chemistry provided by HASi in combination with osteogenic-induced MSCs facilitated better vascularisation that lead to neo-osteogenesis.     

Ultrasound-modulated optical tomography: recovery of amplitude of vibration in the insonified region from boundary measurement of light correlation

We address a certain inverse problem in ultrasound-modulated optical tomography: the recovery of the amplitude of vibration of scatterers [p(r)] in the ultrasound focal volume in a diffusive object from boundary measurement of the modulation depth (M) of the amplitude autocorrelation of light [φ(r,τ)] traversing through it. Since M is dependent on the stiffness of the material, this is the precursor to elasticity imaging. The propagation of φ(r,τ) is described by a diffusion equation from which we have derived a nonlinear perturbation equation connecting p(r) and refractive index modulation [Δn(r)] in the region of interest to M measured on the boundary. The nonlinear perturbation equation and its approximate linear counterpart are solved for the recovery of p(r). The numerical results reveal regions of different stiffness, proving that the present method recovers p(r) with reasonable quantitative accuracy and spatial resolution.     

Synthesis,spectroscopic characterization,DNA cleavage and antibacterial studies of a novel tridentate Schiff base and some lanthanide（III） complexes

A novel potential tridentate Schiff base was prepared by condensing equimolar quantities of 2-hydroxyacetophenone and 2-aminopyrimidine in methanol. This ligand was versatile in forming a series of complexes with lanthanide ions such as La（III）, Pr（III）, Nd（III）, Sm（III）, Gd（III）, Dy（III） and Yb（III）. The ligand and the metal complexes were characterized through elemental analysis, molar conductance, UV-Visible, IR, 1H NMR, and mass spectral studies. The spectral studies indicated that the ligand was coordinated to the metal ion in neutral tridentate fashion through the azomethine nitrogen, one of the nitrogen atoms in the pyrimidine ring and the phenolic oxygen without deprotonation. Thermal decomposition and luminescence property of lanthanum（III） complex were also examined. The X-ray diffraction patterns showed the crystalline nature of the ligand and its lanthanum（III） complex. The DNA cleavage studies of the ligand and the metal complexes were carried out and it was observed that the lanthanum（III） and neo-dymium（III） complexes cleaved the pUC19 DNA effectively. The ligand and the metal complexes were screened for their antibacte-rial activities. The metal complexes were found to be more potent bactericides than the ligand.     

Varactor controlled frequency and polarization reconfigurable microstrip antenna

A single feed compact microstrip antenna achieving frequency and polarization diversity using a varactor is presented. A simple patch antenna with an X‐slot constitutes the fundamental structure. The frequency and polarization agility is realized by varying the reactance of an embedded varactor at the center of the X‐slot with respect to the biasing from 0 to 25 V. The prototype fabricated on a substrate of dielectric constant (ε_r) 4.4 and height (h) 1.6 mm is fed by a proximity feed fabricated using the same substrate. By controlling the bias voltage of the varactor, the polarization of the antenna can be switched between linear and circular polarization. Furthermore, the proposed antenna offers stable broadside radiation characteristics without any extra impedance matching circuit. The frequency and polarization diversities of this design could potentially improve the reliability of wireless communication systems. The details of the antenna are presented and discussed. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2011.     

High Security Identity Tags Using Spiral Resonators

A highly compact chipless tag based on Frequency coding technique using Spiral Resonators is proposed in this paper. Spirals are well known metamaterial structures and thus capable of sharp resonance, and hence Spiral Resonators can serve as a good candidate for RF Identity Tags. The bit capacity of the proposed tag is 10 bits per sqcm. The prototype of the tag is fabricated on a low-cost substrate of dielectric constant 4.4 and loss tangent 0.02. The overall dimension of tag is 15.4 x 3 x 1.6 mm³. Two methods for reading the tags are also discussed in this paper. Scope for bit enhancement is also provided.     

Nickel/carbon hybrid nanostructures as microwave absorbers

Magnetic metal/carbon hybrid nanostructures are novel materials having multifunctional properties. Here we report the microwave absorbing properties of nickel/carbon nanostructures synthesized by a controlled pyrolysis method. Their complex dielectric permittivity and magnetic permeability were measured at different microwave frequencies using the technique of cavity perturbation. Reflection losses were evaluated and found to be less than −10 dB over the entire X-band (8-12 GHz) for a thickness of 2.2-2.8 mm. A minimum reflection loss of −45 dB was attained for an absorber thickness of 6.6 mm at 3.13 GHz.