495 research outputs found

    Electronic structure of nanoscale iron oxide particles measured by scanning tunneling and photoelectron spectroscopies

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    We have investigated the electronic structure of nano-sized iron oxide by scanning tunnelling microscopy (STM) and spectroscopy (STS) as well as by photoelectron spectroscopy. Nano particles were produced by thermal treatment of Ferritin molecules containing a self-assembled core of iron oxide. Depending on the thermal treatment we were able to prepare different phases of iron oxide nanoparticles resembling gamma-Fe2O3, alpha-Fe2O3, and a phase which apparently contains both gamma-Fe2O3 and alpha-Fe2O3. Changes to the electronic structure of these materials were studied under reducing conditions. We show that the surface band gap of the electronic excitation spectrum can differ from that of bulk material and is dominated by surface effects.Comment: REVTeX, 6 pages, 10 figures, submitted to PR

    Short Communication - Comparision of microscopy and RDTs techniques for laboratory detection of malaria

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    The development of rapid and specific diagnostic test to identify individuals infected with malaria is important to control severe public health impact of this disease.This study evaluated the ability of rapid malaria diagnostic test (BIOTEC Malaria P.v/P.f rapid device) to detect Plasmodium falciparum and Plasmodium vivax malaria during out break in Chabahar province of Sistan and Balouchestan in Iran. Whole blood samples were obtained from 250 suspected malaria patients. Results from these kit were compared to the reading obtained from 100 fields of Giemsa-stained thick smear blood film.This test is rapid (15 min) for malaria detection. The device is coated with monoclonal antibodies against P. falciparum histidine rich protein-2 (PfHRP2) and enzyme parasite lactate dehydrogenase isomer of P. vivax (PLDH) . A total of 55% samples (138 of 250) were positive by blood films, while 54% samples (136 of 250) were positive by malaria P.v/P.f rapid device. The blood film indicated that 81% (112 of 138) of patients were positive for P.vivax and 19% (26 of 138) of patients were positive for P. falciparum. The malaria P.v/P.f rapid device showed that 79.6% (110 of 138) were positive for P.vivax and 1.4% (2 of 138) were negative. 19% (26 of 138) were positive for P. falciparum. These results demonstrated that the malaria P.v/P.f rapid device had sensitivity of 98.5% and specificity of 100% when compared to traditional blood films. The malaria P.v/P.f rapid device showed an excellent correlation with traditional blood films in identification of both P. vivax and P. falciparum malaria. At present for diagnosis of malaria in endemic area, this kit is rather expensive when compared to microscopy. Neverthless, it is very useful for remote areas where the necessary facilities for microscopic examination are not accessible

    Statistical properties of a localization-delocalization transition induced by correlated disorder

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    The exact probability distributions of the resistance, the conductance and the transmission are calculated for the one-dimensional Anderson model with long-range correlated off-diagonal disorder at E=0. It is proved that despite of the Anderson transition in 3D, the functional form of the resistance (and its related variables) distribution function does not change when there exists a Metal-Insulator transition induced by correlation between disorders. Furthermore, we derive analytically all statistical moments of the resistance, the transmission and the Lyapunov Exponent. The growth rate of the average and typical resistance decreases when the Hurst exponent HH tends to its critical value (Hcr=1/2H_{cr}=1/2) from the insulating regime. In the metallic regime H1/2H\geq1/2, the distributions become independent of size. Therefore, the resistance and the transmission fluctuations do not diverge with system size in the thermodynamic limit

    Quality of Life Among Veterans With Chronic Spinal Cord Injury and Related Variables

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    Background: In recent decades, the incidence of spinal cord injuries has increased. In a systemic review on epidemiology of traumatic spinal cord injury in developing countries reported 25.5/million cases per year. Objectives: To assess the quality of life (QOL) of the veterans among Iran-Iraq war with chronic spinal cord injuries (SCI) and to evaluate long-term impressions of SCI on their quality of life. Patients and Methods: Fifty-two veterans, all male, with chronic spinal cord injury from Iran-Iraq war (1980-1988) were interviewed and examined. The mean age of veterans at the time of interview was 49.3 years (38 to 80 years). Veterans were assessed by using a 36-item short-form (SF-36), hospital anxiety and depression scale (HADS) and the Barthel index. The presence or absence of pressure sores and spasticity were documented as well. Results: The mean age of veterans at the time of study was 49.3 years. Pearson's correlation test showed that depression and anxiety have a reverse association with mental component summary (MCS) scale and physical component summary (PCS) scale scores, respectively. Regression analysis showed a negative effect of depression and pressure sore on PCS. Moreover, no association was found between the duration of injury and age with quality of life. Conclusions: Lower QOL was found among veterans with chronic SCI. More researches on health-related quality of life (HRQOL) are needed to give us a better understanding of changes in life of patients with SCI and the ways to improve them

    Quantum teleportation with nonclassical correlated states in noninertial frames

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    Quantum teleportation is studied in noninertial frame, for fermionic case, when Alice and Bob share a general nonclassical correlated state. In noninertial frames two fidelities of teleportation are given. It is found that the average fidelity of teleportation from a separable and nonclassical correlated state is increasing with the amount of nonclassical correlation of the state. However, for any particular nonclassical correlated state, the fidelity of teleportation decreases by increasing the acceleration.Comment: 10 pages, 3 figures, expanded version to appear in Quantum Inf. Proces

    An investigation on resistance of 19 common bean genotypes to two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), in three regions of Iran

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    Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of common bean that causes serious damage to agricultural crops. In this study, nineteen common bean genotypes were evaluated for resistance to the two-spotted spider mite. The trial was carried out at field conditions of Karaj, Brojerd and Khomein. One week after mite infestation, the total number of female and eggs were counted for two times. Also, mite damage feeding was evaluated with a 1-6 scale. Khomein had the fewest infested mean and relative resistance of many genotypes was failed in comparison to susceptible standard genotype (Akhtar) at Khomein. So they should be eliminated in alternative breeding programs. Nevertheless, only Ks41128 that had good relative resistance at other regions had the most relative resistance at Khomein. Subsequently, we propose Ks41128 as the most resistance and also the most stable genotypes

    The risk factors and related hospitalizations for cases with positive and negative COVID-19 tests: A case-control study

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    Background: The aim of this study was to evaluate the risk factors for hospitalizations of cases with positive and negative COVID-19 tests. Methods: In this case-control study, the case and control groups consisted of 292 COVID-19 patients and 296 non-COVID-19 patients. Patients who referred to a reference laboratory in Tehran (Iran) in March 2020 were selected and interviewed. The patients were contacted by telephone and data were recorded through a questionnaire. Results: The sample of this study consisted of 588 patients (349 59% females, 239 41% males) with a mean age of 42 ± 15. The results of this study showed that comorbidities like diabetes (OR = 7.42), hypertension (OR = 4.85), asthma and respiratory diseases (OR = 5.64) in addition to symptoms including fever (OR = 6.67), chills (OR = 11.2), anorexia (OR = 11.3), dyspnea (OR = 4.8), weakness and lethargy (OR = 5.7) were the most predictive variables for hospitalization of non-COVID-19 cases. Furthermore, demographical variables like male gender (OR = 3.71), high age (>50; OR = 3.12), BMI (>25; OR = 2.37), travel (OR = 2.79), comorbidities including diabetes (OR = 5.26), hypertension (OR = 3.7) and underlying immunosuppressant patients receiving corticosteroid therapy (OR = 3.62) in addition to symptoms like anorexia OR = 2.55 and dyspnea (OR = 6.99) tend to increase the risk of hospital admission in COVID-19 patients, suggesting their predictive values for hospitalization of COVID-19 patients. Conclusion: Our results indicated that different factors tend to increase the odds of hospital admission in patients with positive and negative COVID-19 tests, suggesting their predictive values for hospitalization. © 202

    Observational Constraints on the Modified Gravity Model (MOG) Proposed by Moffat: Using the Magellanic System

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    A simple model for the dynamics of the Magellanic Stream (MS), in the framework of modified gravity models is investigated. We assume that the galaxy is made up of baryonic matter out of context of dark matter scenario. The model we used here is named Modified Gravity (MOG) proposed by Moffat (2005). In order to examine the compatibility of the overall properties of the MS under the MOG theory, the observational radial velocity profile of the MS is compared with the numerical results using the χ2\chi^2 fit method. In order to obtain the best model parameters, a maximum likelihood analysis is performed. We also compare the results of this model with the Cold Dark Matter (CDM) halo model and the other alternative gravity model that proposed by Bekenstein (2004), so called TeVeS. We show that by selecting the appropriate values for the free parameters, the MOG theory seems to be plausible to explain the dynamics of the MS as well as the CDM and the TeVeS models.Comment: 14 pages, 3 Figures, accepted in Int. J. Theor. Phy

    Transcription of toll-like receptors 2, 3, 4 and 9, FoxP3 and Th17 cytokines in a susceptible experimental model of canine Leishmania infantum infection

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    Canine leishmaniosis (CanL) due to Leishmania infantum is a chronic zoonotic systemic disease resulting from complex interactions between protozoa and the canine immune system. Toll-like receptors (TLRs) are essential components of the innate immune system and facilitate the early detection of many infections. However, the role of TLRs in CanL remains unknown and information describing TLR transcription during infection is extremely scarce. The aim of this research project was to investigate the impact of L. infantum infection on canine TLR transcription using a susceptible model. The objectives of this study were to evaluate transcription of TLRs 2, 3, 4 and 9 by means of quantitative reverse transcription polymerase chain reaction (qRT-PCR) in skin, spleen, lymph node and liver in the presence or absence of experimental L. infantum infection in Beagle dogs. These findings were compared with clinical and serological data, parasite densities in infected tissues and transcription of IL-17, IL-22 and FoxP3 in different tissues in non-infected dogs (n = 10), and at six months (n = 24) and 15 months (n = 7) post infection. Results revealed significant down regulation of transcription with disease progression in lymph node samples for TLR3, TLR4, TLR9, IL-17, IL-22 and FoxP3. In spleen samples, significant down regulation of transcription was seen in TLR4 and IL-22 when both infected groups were compared with controls. In liver samples, down regulation of transcription was evident with disease progression for IL-22. In the skin, upregulation was seen only for TLR9 and FoxP3 in the early stages of infection. Subtle changes or down regulation in TLR transcription, Th17 cytokines and FoxP3 are indicative of the silent establishment of infection that Leishmania is renowned for. These observations provide new insights about TLR transcription, Th17 cytokines and Foxp3 in the liver, spleen, lymph node and skin in CanL and highlight possible markers of disease susceptibility in this model
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