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Background: Various studies have reported the prevalence of low back pain in specific populations very differently. The aim of the present study was to determine the prevalence of low back pain and related factors among the referees to health centers in Dehloran, Iran. Material and methods: In this cross sectional study, two hundred and seventy three referees to health centers in Dehloran, who aged between 20 to 45 years old and were satisfied to be studied, were entered to the study after providing signed written consent form. The data were collected using the valid/reliable researcher -made questionnaire. The validity of the questionnaire has been obtained by inserting the experts' views in the questionnaire and the reliability was measured through cronbach's alpha which was calculated as 78%. The data has been analyzed using SPSS16. Results: The lifetime prevalence of low back pain among the studied participants was 52.38%. There were significant relationship between low back pain and education level, residency location, hours per day working with computer and sedentary life style. (All p value was < 0.05). Conclusion: This study showed low back pain was prevalent among referees to health centers aged between 20 to 45 years old. Sedentary life style and much working with computer were related significant factors. Designing proper intervention to prevent low back pain among this target group is recommended.  

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In recent years, with the advancement of nanoscience, many scientists have used nano materials to solve existing problems in various sectors of oil industry. Nanofluids made with these materials can facilitate the separation of oil and gas in a reservoir and increase oil recovery factor compared to current methods. Therefore, in this work, the effect of clay nanoparticles on oil recovery factor was investigated. For this purpose, two different base fluids, water and ethanol, were used to disperse the nanoparticles. The effect of adding clay nanoparticles on viscosity changes and interfacial surface tension was determined. Also, in order to investigate the effect of nanoparticle concentration in the base fluid on the ultimate oil recovery factor, nanofluids with 3 and 5 wt% were prepared. Results show that oil recovery factor increases significantly in these conditions by adding them into the base fluid, though nanofluids included clay nanoparticles have less stability. Also, the effect of these nanoparticles dispersed in water is greater than in ethanol. For example, at 5 wt%, oil recovery factor for water based nanofluid was 49.7% and for ethanol based nanofluid was 46%.

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Aims: Saffron is one of the plants, whose allelopathic effect of various organs have been reported to affect seed germination of some weed species. The present research was conducted with the aim of evaluating the allelopathic effect of extraction solution of leaves and corms of saffron (Crocus sativus) in phenological stages on seed germination of jimson weed (Datura stramonium).
Materials and Methods: In this experimental study, an experiment was conducted to study the allelopathic effects of saffron on jimson weed seed germination at research farm, Tarbiat Modares University Faculty of Agriculture in autumn 2014. The experiment was arranged as factorial split plot in a completely randomized design with 3 replications. The treatments included factorial combination of 2 extract types (water and alcohol), 3 tissue compositions of saffron organs, different concentrations of aqueous, and alcoholic extracts as the main plots and 3 different phonological stages of saffron were considered as sub-plots. One-way analysis of variance was performed through generalized linear model (GLM), using SAS 9.1 software, and drawing charts was done, using Excel2013 software.
Findings: The concentration and phonological stage of saffron had a significant effect on the germination percentage of Datura stramonium, but the main effect of organ type on this trait was not significant. The aqueous extract of saffron did not have significant effect on the germination of Datura stramonium germination at the phonological stage of the daughter corms at a concentration of 2g/l in comparison with other phonological stages, but at a concentration of 4g, it significantly decreased the seed germination.
Conclusion: Extract of saffron has an allelopathic potential, and germination traits, including germination percentage and plumule and radicle length of Datura stramonium in different phonological stages of saffron are affected by the aqueous and alcoholic extracts of different organs.

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Objective: In this study, a SYBR Green real-time RT-PCR assay for quantification of HIV-1 viral RNA was developed. Materials and Methods: This assay was performed based on amplification of the pol region of HIV-1 and product analysis by an ABI 7500 system. We quantified HIV-1 viral load in 26 seropositive patients by this system and the data were subsequently compared with results obtained with a reference technique represented by COBAS AMPLICOR HIV-1 Monitor test. Results: The results demonstrated that this technique could detecte up to 500 HIV-1 RNA copies/ml of plasma. The linearity of this approach was conserved over a wide range of HIV-1 copy numbers (5×102-5×109). Since no positive signal was observed in seronegative volunteers, the specificity of the test was calculated as 100%. Comparison of the results with those obtained by the reference quantification method, revealed a significant correlation between the results (R2= 0.95). Conclusion: On the basis of the most recent recorded cases for HIV-1 infection and AIDS in Iran, the prevalence of this disease is rising rapidly and the situation has been called to be alarming by national health representatives. Determination of HIV-1 viral load in plasma has been considered as the most effective single prediction tool of clinical outcome. Indeed, the development and stabilization of HIV-1 RNA assays have given physicians a unique tool for monitoring HIV-1 patients treated with antiviral drugs. In this study, we have developed a SYBR-Green Real Time RT-PCR assay for quantitative analysis of HIV-1 in infected patients. Since a synthetic RNA standard was used in this assay, the upper limit of detection was detected to be higher than the standard test (5×10 9 versus 7.5×10 5). This can be important in patients with acute high viral load infections. Reproducibility was assessed by Intra assay and Inter assay analysis. Coefficient of variations Ct, in reproducibility tests for Intra assay and Inter assay variability were less than

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Objective: The global HIV epidemic continues to expand and exceeding previous predictions. An effective vaccine represents the best hope to curtail the HIV epidemic. DNA vaccines induce humoral and cellular responses and mimic live vaccines without their pathogenic potential. The importance of CD8+ CTL responses in controlling HIV and SIV viremia has led to production of a series of vaccine candidates that effectively induce these responses. It is now widely believed that an HIV vaccine strategy must stimulate both a strong humoral (antibody) as well as cell-mediated (CTL) immune response.The p24 and gp41 play many important roles in host-virus interaction and pathogenesis. These proteins are considered as attractive vaccine candidate in which their immunogenecity and immunomodulatory effects have been confirmed. Materials and Methods: In this study, a construct, pcDNA3.1Hygro- (p24-gp41), was evaluated as a DNA vaccine candidate in Balb/C mice for generation of effective cellular immune responses. For immunizing, we used dendrosome, a novel family of vehicles for transfection and therapy. IFN-γ cytokine production and total antibody were detected by ELISA. Lymphoprolifration assay was performed by MTT test. Results: ELISA and MTT assays confirmed that the cited p24-gp41 fusion gene is able to enhance immune responses in mice. Conclusion: The construct that was used in this research can be a good candidate for DNA vaccine against HIV-1, if the future complementary tests demonstrate the same trends of immunogenic responses shown in this study.

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This paper investigates the robust finite time stability and finite time stabilization for a class of uncertain switched systems which have time delay. The emphasis of the paper is on the cases where uncertainties are time varying and unknown but norm bounded. By using the average dwell time approach and multiple Lyapunov like functions, delay dependent sufficient conditions for finite time stability of uncertain switched systems with time delay in terms of a set of the linear matrix inequalities are presented. Then, the corresponding conditions are obtained for finite time stabilization of uncertain switched time delay systems via a state feedback controller. The controller is designed by virtue of the linear matrix inequalities and the cone complement linearization method. We solved the problem of uncertainty in uncertain switched time delay systems by resorting to Yakubovich lemma. Finally, numerical examples are provided to verify the effectiveness of the proposed theorem.
 

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Objective: Bone morphogenetic protein-7 (BMP-7) is a multifunctional growth factor predominantly recognized for its osteoinductive properties. Due to the high cost of this protein, the availability of BMP-7 for treatment is limited. The heterologous production of recombinant hBMP-7 has been performed in a number of expression systems. In this study a novel form of BMP-7 was expressed in eukaryotic and prokaryotic hosts. Methods: For expression in the prokaryotic system, the novel protein was secreted to the periplasmic space of Escherichia coli using a pelB signal sequence followed by single-step purification by Ni²⁺-charged column chromatography. In the mammalian cell expression system, we transferred a full-length cDNA encoding precursor of the novel protein to CHO cells then selected stable clones by using the appropriate antibiotic concentration. Expressions in both systems were confirmed by Western blot analysis. Results: The novel recombinant protein was produced as a 36-38 kDa dimer in the CHO cell line and a 16 kDa monomer in the Escherichia coli system. Quantitative analysis according to ELISA showed that the expression levels of the mutant protein in the eukaryotic and prokaryotic expression systems were 40 ng/ml and 135 ng/ml of the culture media, respectively. Conclusion: In this study, the expression level in Escherichia coli was at least three times more than observed in the CHO cells. However, further optimization is required to obtain a dimer protein in Escherichia coli. The results show that periplasmic expression may be suitable for the production of complex proteins such as BMPs.

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Newcastle disease virus (NDV) causes one of the most dangerous infections in birds. High economic losses and high mortality are outcomes of this virus, which does not have any immediate cure. The natural reservoir of this virus can remain among bird and non-bird animals like farm animals. In Iran, this virus has reached a steady situation. Also, it should be mentioned that migrating birds can transfer the virus. The F protein of the virus is essential in pathogenicity and determination of pathogenic strain of NDVs, which has the regions that are essential in pathogenicity, immunogenicity, cell fusibility, and tissue necrosis. In this study, with computational analysis of this protein, some features related to this protein such as protein cleavage site, the conserved region in immunogenicity, infected species in Middle Eastern countries, and physicochemical properties of protein were determined. Results showed that the F protein of NDV consists of highly conserved regions that show a high rate of similarity and identity. Despite the majority of strains characterized as pathogenic, there were still non-pathogenic strains circulating in the Middle East. In this comprehensive study, protein regions essential in immunogenicity and epitope formation were identified, which may be used in the development of recombinant vaccines against this virus.
 

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Objective: Development of high producing mammalian cell lines is a major bottleneck in manufacturing of recombinant therapeutic proteins. This study examines the effect of using the matrix attachment region from the human interferon beta gene in combination with promoter activation strategy with E1A 13S protein on human tissue plasminogen activator (t-PA) expression in Chinese hamster ovary (CHO) cells. Methods: The matrix attachment region was cloned in 3΄ and 5΄ flanking sides of the t-PA expression cassette in pTPA vector to generate pMTPA. After transfection of the cells with pTPA and pMTPA vectors, stable cell pools were developed and the t-PA expression level determined for each stable cell line. In the next step, E1A 13S expression plasmid was transfected to stable cell pools and t-PA titers were measured after 72 hours. Results: Integration of pTPA and pMTPA vectors in the CHO genome was confirmed by PCR analysis on genomic DNA of stable cell pools. Analysis of the t-PA expression level showed a three-fold enhancement in pMTPA transfected cells compared to pTPA-containing cells. t-PA expression was further enhanced up to 1771 U/ml by transient expression of E1A 13S in pMTPA stable cell pools. Conclusion: These results have shown that incorporation of matrix attachment region in an expression vector in combination with promoter activation can effectively enhance recombinant protein expression levels in CHO cells.

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In this work, the effect of carbon nanotube (CNT) size on the effective elastic properties of a hybrid composite reinforced by fuzzy fiber is investigated using a unit cell-based micromechanical approach. This hybrid nanocomposite is composed of the CNT, carbon fiber, polymer matrix and interphase created due to the non-bonded van der Waals interactions between the CNTs and polymer. The novel constructional feature of this hybrid nanocomposite is that the uniformly aligned CNTs are radially grown on the surface of the horizontal carbon fibers. The CNT and carbon fiber are modeled as a transverse isotropic solid, while the interphase and polymer matrix are assumed to be isotropic. The influence of CNT size on the overall behavior of polymer matrix nanocomposite (PMNC), composite fuzzy fiber (CFF) and hybrid composite reinforced with fuzzy fiber is examined. Results show that size of CNT is more significant for the transverse effective properties of the hybrid nanocomposites reinforced with fuzzy fiber. It has been found that the transverse effective properties of hybrid nanocomposite are improved with increasing the CNT size. The micromechanical model is also used to examine the influence of interphase on the overall behavior of the PMNC, CFF and hybrid composite reinforced with fuzzy fiber. The effective elastic properties of the hybrid composite obtained by the present micromechanical model demonstrate very good agreement with those predicted by the other researches.

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The change in the price of real and financial assets is one of the factors that cause business cycle through different channels such as consumption, investment, firm’s balance sheet, and net export. With attention to aware of factor causing on business cycle in Adopting Economic policies, in this paper, we investigated the effect of stock market, house price, exchange rate, and liquidity on business cycle using linear and nonlinear LSTR models and season’s data in the period of 1991-2018. In nonlinear model, which is more suitable for explaining the relationship between variables in comparison with linear model, the cyclical component of the exchange rate selected as the transition variable and the value of the transition parameter was estimated to be 83.89 rials. Considering the estimated value of the transmission parameter, in the period, there were two regimes in the Iranian economy, low-exchange rate regime and a high-exchange rate regime. The results indicate that in both regimes, an increase in stock prices and liquidity cause economic expansion. Also, an increase in house prices and a decline in the exchange rate in the first regime put the economy at an expansion phase and put the economy at a recession phase in the second regime. Therefore, in order to expanding the economy, it is suggested that, on the one hand, the exchange rate be kept low and, on the other hand, increase housing price, stock price and liquidity.
 
 

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