Antioxidant and antihemolytic activities of methanol extract of Hyssopus angustifolius

This study was designed to evaluate antioxidant and antihemolytic activities of Hyssopus angustifolius flower, stem and leaf methanol extracts by employing various in vitro assays. The leaf extract showed the best activity in DPPH (63.2 ± 2.3 μg mL-1) and H2O2  (55.6 ± 2.6 μg mL-1) models compared to the other extracts. However, flower extract exhibited the highest Fe2+ chelating activity (131.4 ± 4.4 μg mL-1). The extracts exhibited good antioxidant activity in linoleic acid peroxidation and reducing power assays, but were not comparable to vitamin C. The stem (23.58 ± 0.7 μg mL-1) and leaf (26.21 ± 1 μg mL-1) extracts showed highest level of antihemolytic activity than the flower extract

On the acoustic levitation stability behaviour of spherical and ellipsoidal particles

We present here an in-depth analysis of particle levitation stability and the role of the radial and axial forces exerted on fixed spherical and ellipsoidal particles levitated in an axisymmetric acoustic levitator, over a wide range of particle sizes and surrounding medium viscosities. We show that the stability behaviour of a levitated particle in an axisymmetric levitator is unequivocally connected to the radial forces: the loss of levitation stability is always due to the change of the radial force sign from positive to negative. It is found that the axial force exerted on a sphere of radius ${R}_{s}$ increases with increasing viscosity for ${R}_{s} / \lambda \lt 0. 0125$ ( $\lambda$ is the acoustic wavelength), with the viscous contribution of this force scaling with the inverse of the sphere radius. The axial force decreases with increasing viscosity for spheres with ${R}_{s} / \lambda \gt 0. 0125$ . The radial force, on the other hand, decreases monotonically with increasing viscosity. The radial and axial forces exerted on an ellipsoidal particle are larger than those exerted on a volume-equivalent sphere, up to the point where the ellipsoid starts to act as an obstacle to the formation of the standing wave in the levitator chambe

Magneto-optical study of thermally annealed InAs-InGaAs-GaAs self-assembled quantum dots

We report a magneto-optical study of InAs-InGaAs-GaAs self-assembled quantum dots (QDs) subjected to post-growth thermal annealing at different temperatures. At low temperatures annealing strongly affects the bimodal distribution of QDs; at higher temperatures a strong blueshift of the emission occurs. Magnetophotoluminescence reveals that the annealing increases the QD size, with a larger effect occurring along the growth axis, and decreases the carrier effective masses. The main contribution to the blueshift is deduced to be an increase in the average Ga composition of the QDs. The inadvertent annealing which occurs during the growth of the upper AlGaAs cladding layer in laser structures is also studied

Influence of sacrificial bonds on the mechanical behaviour of polymer chains

A growing focus in modern materials science is the attempt to transfer principles found in nature into new technological concepts with the goal of producing novel materials with tailored mechanical properties. One of these principles used in nature is the concept of sacrificial bonding (i.e. non-covalent cross-links that rupture prior to the protein backbone), which is associated with increased toughness in many biological materials. In the present work, the influence of the number and distribution of sacrificial bonds (SBs) on three main mechanical parameters—strength, work to fracture and apparent stiffness—is investigated in a simple model system using computer simulations. The results show that the work to fracture is mainly determined by the number of SBs present in the system, while the apparent stiffness and, to a lesser extent, the strength is altered when the distribution of SBs is changed. </jats:p

The use of embolic signal detection in multicenter trials to evaluate antiplatelet efficacy: signal analysis and quality control mechanisms in the CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotid Stenosis) trial

&lt;p&gt;&lt;b&gt;Background and Purpose:&lt;/b&gt; The CARESS (Clopidogrel and Aspirin for Reduction of Emboli in Symptomatic carotid Stenosis) trial proved the effectiveness of the combination of clopidogrel and aspirin compared with aspirin alone in reducing presence and number of microembolic signals (MES) in patients with recently symptomatic carotid stenosis. The present study aimed at installing primary and secondary quality control measures in CARESS because MES evaluation relies on subjective judgment by human experts.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods:&lt;/b&gt; As primary quality control, centers participating in CARESS evaluated a reference digital audio tape (DAT) before the study containing both MES and artifacts. Interobserver agreement of classifying signals as MES was expressed as proportions of specific agreement of positive ratings (ps±values). For all DATs included in CARESS (n=300), online number of MES and off-line number of MES read by the central reader were compared using correlation coefficients. As secondary control, a sample of 16 of 300 DATs was cross-validated by another independent reader (post-trial validator).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Results:&lt;/b&gt; For the reference tape, the cumulative ps±value was 0.894 based on 12 of 14 observers. Two observers with very different results improved after a training procedure. Agreement between post-trial validator and central reader was ps+=0.805, indicating very good agreement. Correlation between online evaluation and off-line evaluation of DATs was very good overall (cumulative ρ=0.84; P&#60;0.001).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusion:&lt;/b&gt; Multicenter studies using MES as outcome parameter are feasible. However, primary and secondary quality control procedures are important.&lt;/p&gt

Implications of factorization for the determination of hadronic form factors in D_s^+ \ra \phi transition

Using factorization we determine the allowed domains of the ratios of form factors, $x = A_2(0)/A_1(0)$ and $y = V(0)/A_1(0)$, from the experimentally measured ratio R_h \equiv \Gamma(D_s^+ \ra \phi \rho^+)/\Gamma(D_s^+ \ra \phi \pi^+) assuming three different scenarios for the $q^2$-dependence of the form factors. We find that the allowed domains overlap with those obtained by using the experimentally measured ratio R_{s\ell} = \Gamma(D^+_s \ra \phi \ell^+ \nu_{\ell})/\Gamma(D^+_s \ra \phi \pi^+) provided that the phenomenological parameter $a_1$ is $1.23$. Such a comparison presents a genuine test of factorization. We calculate the longitudinal polarization fraction, \Gamma_L/\Gamma \equiv \Gamma(D_s^+ \ra \phi_L \rho^+_L)/\Gamma(D_s^+ \ra \phi \rho^+), in the three scenarios for the $q^2$-dependence of the form factors and emphasize the importance of measuring $\Gamma_L/\Gamma$. Finally we discuss the $q^2$-distribution of the semileptonic decay and find that it is rather insensitive to the scenarios for the $q^2$-dependence of the form factors, and unless very accurate data can be obtained it is unlikely to discriminate between the different scenarios. Useful information on the value of $x$ might be obtained by the magnitude of the $q^2$-distribution near $q^2 = 0$. However the most precise information on $x$ and $y$ would come from the knowledge of the longitudinal and left-right transverse polarizations of the final vector mesons in hadronic and/or semileptonic decays.Comment: Latex 10 pages( 4 figures), PAR/LPTHE/94-3

A suggested prototype for assessing bone health

Background- Osteoporosis is becoming a health concern worldwide. Considering the fact that prevention plays an important role in reducing the burden of this silent disease and in view of the limited resources available, many countries have adopted certain programs to fight osteoporosis through shifting their attention towards at-risk individuals. The Iranian Multicenter Osteoporosis Study (IMOS) is one of these programs. The program aims to assess bone health and the prevalence of vitamin D deficiency in different parts of Iran with various altitudes, latitudes and lifestyle habits in a way that the results could be generalized to the country. Method- The present article presents the protocol used in the third phase of the study. It was designed based on the experiences gathered in the previous phases to overcome the shortcomings particularly subject loss. The questionnaire applied in this study was developed based on a thorough literature review of the risk factors and secondary causes of osteoporosis and was approved by an expert panel. It should be added that while the majority of the existing studies aim to study a certain aspect of osteoporosis, the present protocol provides the information needed for policy makers and researchers to study different osteoporosis-related issues. Conclusion- The authors believe the protocol, to be implemented with small modifications, can help policymakers in different parts of the world, particularly developing countries, gather accurate information on different aspects of bone health at the national level. © 2015, Academy of Medical Sciences of I.R. Iran. All rights reserved

The relation between environmental parameters of Hormuzgan coastline in Persian Gulf and occurrence of the first harmful algal bloom of Cochlodinium polykrikoides (Gymnodiniaceae)

Cochlodinium polykrikoides was bloomed in the Persian Gulf for the first time in September 2008, started from the Strait of Hormuz and then spread out towards the northern parts covering most of the areas of the Gulf and lasted 8 months. In order to find out environmental conditions during the bloom, a monthly sampling program was carried out in seven surface stations in 2008-2009. At each station, three samples (triplicates) were collected for phytoplankton analysis and also one sample for environmental analyses, including salinity, chlorophyll a and nutrients. Blooms of C. polykrikoides were observed with a seawater temperature of 20.1 to 31.0 °C, salinity 37.0-40.1 ppt and nutrient concentration ranges during the bloom and red tide were 0.064-0.707 mg/l nitrate + nitrite and 0.001-1.66 mg/l phosphate, respectively. Maximum of C. polykrikoides abundance was measured 26 × 106 cells L-1 in October 2008. Kruscal wallis test demonstrated a significant difference in densities and chlorophyll-a in different months and seasons not in different stations. This study showed increase of temperature (>31.0 °C) stopped bloom and red tide due to C. polykrikoides in both the eastern and middle sampling stations but in the western stations was determined decrease in nutrient amounts as the major factor therefore increased nutrient of coastal waters, and environmental conditions could have efficacy the occurrence of this dinoflagellate