Thermodynamics of deposition flux-dependent intrinsic film stress

Article / Letter to editorLeids Instituut Onderzoek NatuurkundeLeiden Institute of Chemistr

Thermodynamics of deposition flux-dependent intrinsic film stress

Article / Letter to editorLeids Instituut Onderzoek NatuurkundeLeiden Institute of Chemistr

Thermodynamics of deposition flux-dependent intrinsic film stress

Article / Letter to editorLeids Instituut Onderzoek NatuurkundeLeiden Institute of Chemistr

Epidemiology and the agreement rate of serological tests in human brucellosis in North East of Iran

Background: Brucellosis still remains a major health problem with different symptoms and various diagnostic methods. Diagnostic methods of brucellosis are usually based on detecting specific antibodies in the patient’s serum. Nowadays, many serological tests are applied for the diagnosis of human brucellosis. Most routine tests are serum agglutination tests based on Wright and 2-Mercaptoethanol (2-ME). Objectives: The aim of this study (cross sectional study) was to evaluate the prevalence of brucellosis and assess the degree of agreement among serum samples of suspected brucellosis serological tests routinely performed in Mashhad, Iran. Patients and Methods: This study was conducted in Mashhad from August 2011 to September 2012. Sera (2 - 3 mL) were collected from 83 cases suspected of brucellosis among 594 patients. Ten serum samples were collected from healthy subjects as control sera. Rose Bengal test for initial screening and Wright and 2 ME as standard tests were conducted to determine antibody titers. Thereafter, IgG and IgM levels were determined by the Enzyme Linked Immunosorbent Assay (ELISA) method. Results: Among 83 serum samples, Rose Bengal test was able to identify 20 (12%) positive specimens; the standard tube agglutination test was able to detect 30 (18%) positive samples, and the ELISA IgG and ELISA IgM were able to trace 42 (21%) and 13 (6.5%) positive samples, respectively. Ten control samples had negative results for the ELISA method. The results were calculated by the Kappa formula. The highest level of agreement was among 1 = KRB-SAT tests and the lowest level of agreement was among tests K ELISA IgM-IgG = 0.30. Conclusions: According to the results, brucellosis has remained endemic in this region. Most cases were detected by ELISA IgG. The highest kappa agreements were between tests KRB-SAT, KRB-IgG and KSAT-IgG, while the lowest levels of agreement were between tests SAT-IgM and ELISA IgM-IgG. Considering that ELISA IgM results are covered by SAT and ELISA IgG test results, applications of this test do not seem necessary. © 2015, Infectious Diseases and Tropical Medicine Research Center

Examination of the Nonlinear Dynamics of a Chaotic Acousto-optic Bragg Modulator with Feedback under Signal Encryption and Decryption

An acousto-optic Bragg cell with first-order feedback, which exhibits chaotic behavior past the threshold for bistability, was recently examined for possible chaotic encryption and recovery of simple messages (such as low-amplitude periodic signals) applied via the bias input of the sound cell driver. We carry out a thorough examination of the nonlinear dynamics of the Bragg cell under intensity feedback for (i) dc variations of the feedback gain (β˜) and the phase shift parameter (α^ 0) and (ii) ac variations of α^ 0; total under signal encryption, investigating both from two different perspectives: (i) examining chaos in view of the so-called Lyapunov exponent derived recently by Ghosh and Verma and (ii) examining chaos in terms of the familiar bifurcation maps of intensity plotted against the feedback gain and the effective bias. It is shown that overall, the nonlinear dynamical results using the two approaches broadly agree, both for dc (fixed-parameter) analyses and, more importantly, when applied to the case of ac signal encryption cases. This affirms the effectiveness of the nonlinear dynamical theory in predicting and tracking the actual physical behavior of this system for message signal transmission and recovery under complex chaotic encryption

Chaotic Bandgaps in Hybrid Acousto-optic Feedback and their Implications

The nonlinear dynamics of a hybrid acousto-optic device was examined from the perspective of the Lyapunov exponent (LE) and bifurcation maps. The plots for LE versus system parameters and bifurcation maps have recently been examined against known simulation results including chaotic encryption experiments [1]. It is verified that the loop gain (feedback gain (β) times incident light amplitude (Iin) needs to be greater than one as a necessary , but not sufficient condition for the onset of chaos. It is found that for certain combinations of β, Iin, net bias voltage (αtοt), and the initial value of the first-order scattered light (I1(0)), there are pronounced regions of chaos in the parameter field, while for others, chaos is minimal. It is also observed that in some cases, the negative spikes in the LE are far larger than its positive amplitudes, hence indicating a greater tendency to become non-chaotic. Additionally, we have examined the bifurcation plots versus the two most salient system parameters, αtοt and β. These maps have revealed behavior that is by no means uniformly chaotic. It is found that the system moves in and out of chaos within distinct bands along the αtοt and β axes. These results imply strong sensitivity vis-Ã -vis these parameters around the passbands and stopbands , and may indicate control of chaos by appropriate parameter adjustment. Such control may have applications in biological chaos, such as arresting malignant, chaotic cell multiplication. Overall, the dynamical results compare favorably with time-domain characteristics of encrypted chaotic waveforms in signal modulation and transmission applications

Examination of Chaotic Signal Encryption and Recovery for Secure Communication using Hybrid Acousto-optic Feedback

Generation of chaos from acousto-optic (A-O)Bragg cell modulators with an electronic feedback has been studied for over 3 decades. Since an acousto-optic Bragg cell with zeroth- and first-order feedback exhibits chaotic behavior past the threshold for bistability, such a system was recently examined for possible chaotic encryption of simple messages (such as a low-amplitude sinusoidal signal) applied via the bias input of the sound cell driver. Subsequent recovery of the message signal was carried out via a heterodyne-type strategy employing a locally generated chaotic carrier, with threshold parameters matched to the transmitting Bragg cell. In this paper, we present numerical results and detailed interpretations for signal encryption and recovery under hybrid A-O electronic feedback using a heterodyne strategy. Important features of this setup, such as the system robustness in terms of parameter matching (feedback gain, dc bias, and time delay) are also examined in some detail

Effect of Soil Textural Classes on the Biological Nitrogen Fixation by Bradyrhizobium Measured by 15N Dilution Analysis

The current study was conductedas a pot experiment to determine the effect of soil texture on biological nitrogen fixation (BNF) of six most efficient local isolates, specified, of Bradyrhizobium. Cowpea (Vignaunguiculata L.), as a legume host crop, was used as a host crop and 15N dilution analysis was used for accurate determination of the amount of N biologically fixed under experimental parameters specified. Soils used are clay loam, sandy clay loam and sandy loam. Biological Nitrogen Fixation (BNF), in different soil textural classes, was as in the following order: medium texture soil > heavy texture soil > light textured soil. Statistical analysis showed that there is a significant variation in BNF % among six Iraqi isolates in the three soil textural classes. There is a significant variation in the number of the nodules of the six Isolates in one soil texture. However, nodules number does not agree with the BNF% in the same soil for any isolates. Statistical analysis of the data showed that there were significant differences in plant dry weight among the soil textural classes all over local isolates used in this study. Data also showed that there were significant differences in dry weight under different isolates

In vitro Anti-adenovirus activity of pomegranate (Punica granatum L.) peel extract

Background and aims: Human adenoviruses can cause a diversity of clinical diseases, but there is no antiviral therapy formally approved by adenovirus infections. Thus, antiviral agents derived from medicinal plants which are effective against adenoviruses infections are urgently required. Therefore, this research was aimed to evaluate in vitro antiadenovirus activity of pomegranate (Punica granatum L.) peel extract. Methods: In this research, crude ethanol extract of pomegranate peel was prepared. Anti-adenovirus activity of the extract was evaluated on Hela cell line using MTT (3-4,5-dimethylthiazol–2-yl-2,5-diphenyltetrazolium bromide) assay. The 50% inhibitory concentration (IC50) and 50% Cytotoxicity Concentration (CC50) of the extract were determined using regression analysis. To determine antioxidant activity, total phenol content, and flavonoids content of the extract, the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay; Folin-Ciocalteu method and aluminum chloride colorimetric method was used, respectively. Results: The CC50 and IC50 of the extract were 165±10.1 and 18.6±6.7µg/ml, respectively. The selectivity index (SI), the ratio of CC50 and IC50, was 8.89. The IC50 of DPPH radical was 7.7±1.21 μg/ml, compare with butylated hydroxytoluene (BHT), with IC50 of 25.41±1.89 μg/ml. The total phenol and Flavonoid contents were 282.9 mgGAE/g and 136.6mg/g, respectively. This study revealed that the pomegranate (Punica granatum L.) Conclusion: peel extract exhibited Anti-adenovirus activity, with SI value of 8.9, suggesting its potential use as Anti-adenovirus agents. Also this extract with high phytoconstituents could be a promising source of medicinally important natural compound