288 research outputs found

    Gold nanoparticle and mean inactivation dose of human intestinal colon cancer HT-29 cells

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    Background: Mean inactivation dose is a useful radiobiological parameter for the comparison of human cell survival curves. Objectives: Given the importance and accuracy of these parameters, in the present study, the radio sensitivity enhancement of colon cancer (HT-29) cells in the presence of gold nanoparticles (GNPs) were studied using the mean inactivation dose (MID). Materials and Methods: Naked-GNPs with 50 nm diameters were incubated with HT-29 cells. The cytotoxicity and uptake of these particles on HT-29 cells were assessed. After determining the optimum GNPs concentration, the cells were incubated with gold nanoparticle for 24 hours. The change in the MID value as well as the radio sensitization enhancement under irradiation with 9 MV X-ray beams in the presence of GNPs were evaluated by multiple (3-(4, 5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium)MTS assay. Results: Cell survival in the presence of GNPs was more than 90% and the maximum uptake of GNPs was observed at 60 μM of gold nanoparticles. In contrast, in the presence of GNPs combined with radiation, cell survival and MID value significantly decreased, so that the radio sensitization enhancement was 1.4. Conclusions: Due to the significant reduction in the mean inactivation dose of colon cancer cells in the presence of gold nanoparticles, it seems that GNPs are suitable options to achieve a new approach in order to improve radiotherapy efficiency without increasing the prescribed radiation dose

    Therapeutic efficacy of Trifolium pratense L. on letrozole induced polycystic ovary syndrome in rats

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    Polycystic ovary syndrome (PCOS) is considered as one of the leading endocrine disorders during reproductive age in women. This study designed to determine the therapeutic effects of red clover (Trifolium pratense) on letrozole-induced PCOS in vivo. Forty female Sprague–Dawley rats were equally divided into five groups. Control group with a regular sexual cycle received normal saline (letrozole vehicle). Letrozole (1 mg/kg) was used to induce the PCOS to the rats in the treatment groups. After induction of PCOS, four treatment groups received the normal saline, or clomiphene citrate (1 mg/kg), or red clover extracts (500 or 750 mg/kg) for 30-days. After treatment, ovary and uterus were removed, weighed, and the ovaries were subjected to histopathological studies. Serum testosterone and estradiol levels, antioxidant activities, and lipid profiles were evaluated. Red clover extracts and clomiphene citrate decreased testosterone levels and showed a significant increase in estradiol levels in comparison to PCOS induced group (p<0.05). Red clover administration restored the GSH, SOD and CAT levels (p<0.05) and decreased the NO and MDA levels (p<0.05). Treatments caused no significant change in levels of TG, TC, and FBG factors when compared to PCOS induced group (P>0.05). However, red clover (750 mg/kg) significantly increased HDL and decreased LDL levels when compared to PCOS induced group (P<0.05). Treatment with red clover reduced ovarian weight, volumes of ovarian, medulla, cortex and number of cysts and increased number of oocytes compared to PCOS group. Both red clover and clomiphene citrate could treat the letrozole induced PCOS in rats; however, red clover indicated antioxidant activities more than clomiphene citrate. Red clover may be used for discovering anti-PCOS drugs with lower side effects

    Computational approaches to predict protein functional families and functional sites.

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    Understanding the mechanisms of protein function is indispensable for many biological applications, such as protein engineering and drug design. However, experimental annotations are sparse, and therefore, theoretical strategies are needed to fill the gap. Here, we present the latest developments in building functional subclassifications of protein superfamilies and using evolutionary conservation to detect functional determinants, for example, catalytic-, binding- and specificity-determining residues important for delineating the functional families. We also briefly review other features exploited for functional site detection and new machine learning strategies for combining multiple features

    МОДЕЛИРОВАНИЕ РАСПРЕДЕЛЕНИЯ МАГНИТНОЙ ИНДУКЦИИ КОАКСИАЛЬНО-ЛИНЕЙНОГО ДВИГАТЕЛЯ С АКСИАЛЬНЫМ И РАДИАЛЬНЫМ НАПРАВЛЕНИЕМ НАМАГНИЧИВАНИЯ ПОСТОЯННЫХ МАГНИТОВ

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    The paper presents results of computer simulation and experimental study of magnetic induction distribution in a coaxial linear motor air gap throughout the length of the runner active part at different heights of the air gap between the runner and the inductor magnetic core for motors with axial and radial direction of the permanent magnets magnetization.Представлены результаты компьютерного моделирования и экспериментального исследования распределения магнитной индукции в воздушном зазоре по всей длине активной части бегуна коаксиально-линейного двигателя и при разных высотах воздушного зазора между бегуном и магнитопроводом индуктора для двигателей с аксиальным и радиальным направлением намагничивания постоянных магнитов.Представлені результати комп'ютерного моделювання та експериментального дослідження розподілу магнітної індукції в повітряному зазорі по всій довжині активної частини бігуна коаксіально-лінійного двигуна та при різних висотах повітряного зазору між бігуном та магнітопроводом індуктора для двигунів з аксіальним та радіальним напрямком намагнічування постійних магнітів

    МОДЕЛИРОВАНИЕ РАБОТЫ КОАКСИАЛЬНО-ЛИНЕЙНЫХ ДВИГАТЕЛЕЙ С АКСИАЛЬНЫМ И РАДИАЛЬНЫМ НАПРАВЛЕНИЯМИ НАМАГНИЧИВАНИЯ ПОСТОЯННЫХ МАГНИТОВ ПРИ ДИНАМИЧЕСКОМ РЕЖИМЕ

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    Theoretical and experimental investigations of the amplitude, phase and inertia-power frequency characteristics of two types of coaxial-linear electric motors of back-and-forth motion with permanent magnets, which magnetization vector is directed axially and radially relative to the axis of the runner are carried out. The comparative analysis of characteristics of these motors is presented.Проведены теоретические и экспериментальные исследования амплитудных, фазовых и инерционно-силовых частотных характеристик двух типов коаксиально-линейных электрических двигателей возвратно-поступательного движения с постоянными магнитами, вектор намагничивания которых направлен аксиально и радиально по отношению к оси бегуна, а также выполнен сравнительный анализ характеристик этих двигателей.Проведено теоретичні та експериментальні дослідження амплітудних, фазових та інерційно-силових частотних характеристик двох типів коаксіально-лінійних електричних двигунів зворотно-поступального руху з постійними магнітами, вектор намагнічування яких направлений аксіально та радіально по відношенню до вісі бігуна, а також здійснено порівняльний аналіз характеристик цих двигунів

    Validation of Lexical Frequency Profiles As a Measure of Lexical Richness in Written Discourse

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    Technological developments and their utilities in various areas including education have offered great advantages for man. One of the greatest achievements in this trend has been the innovation in computer software like Lexical Frequency Profiles (LFP) and its pedagogical implications either in teaching or measurement. To take the maximum advantages, this study seeks to validate the LFP as a measure of lexical richness in written discourse of Iranian EFL Learners. 50 students majoring in English Translation participated in this study; each of them was encouraged to develop two compositions on general topics in order to establish VocabProfile indexes. To estimate the reliability of the LFP, the VocabProfile indexes of two writings were correlated, but for the validity purpose, first, a productive version of Vocabulary Levels Test (VLT) was administered and second, the students’ compositions were fed into P_Lex software to elicit P_Lex index. After that, VocabProfile indexes were correlated with VLT scores and P_Lex index separately. The findings of the study revealed that students’ VocabProfile indexes written on two different topics correlated significantly with each other. Because of such a significant correlation coefficients, and the LFP indexes are related to VLT active test and P_Lex index, it is conservatively safe to claim that VocabProfile indexes are to some extent reliable and valid measurement instruments but not strong enough to be used as a stand- alone measure for the assessment of lexical richness. Pedagogically speaking, the LPF is suggested as a relatively reliable and valid measure to be used along with other dependable devices in measuring lexical richness in discourses of various types

    Throughfall Nutrients in a Degraded Indigenous Fagus Orientalis Forest and a Picea Abies Plantation in the of North of Iran

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    Aim of study: The objective of this study was to compare the quantity and quality of TF (throughfall) in an indigenous, but degraded, stand of Fagus orientalis and Picea abies plantation. Area of study: Forests of Kelar-Dasht region located in Mazandaran province, northern Iran. Material and Methods: TF measured by twenty collectors that were distributed randomly underneath each stand. For 21 storms sampled in 2012 (August-December) and 2013 (April-June), we analyzed pH, EC, Ca2+, Mg2+, K+, NO3-, and P of gross rainfall (GR) and TF. Main results: Cumulative interception (I) for F. orientalis and P. abies were 114.2 mm and 194.8 mm of the total GR, respectively. The amount of K+ (13.4 mg L-1) and Ca2+ (0.9 mg L-1) were higher (for both elements, p = 0.001) in the TF of P. abies compared to those of F. orientalis (6.8 and 0.5, mg L-1, respectively) and GR (3.2 and 0.37 mg L-1, respectively). Conversely, mean P concentration was doubled (p = 0.022) in the TF of F. orientalis (11.1 mg L-1) compared to GR (5.8 mg L-1). Research highlights: P. abies plantations may provide a solution for reforestation of degraded F. orientalis forests of northern Iran, yet how P. abies plantations differentially affect the quality and quantity of rainfall reaching subcanopy soils (TF) compared to F. orientalis is unknown. Understanding the connection between hydrological processes and nutrient cycling in forest ecosystems is crucial for choosing the appropriate species to rehabilitate the degraded indigenous forests with nonindigenous species

    Mbd3 Promotes Reprogramming of Primary Human Fibroblasts

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    Mbd3 (Methyl-CpG binding domain protein), a core member of NuRD (nucleosome remodelling and deacetylation) is essential for embryogenesis. However, its role in reprogramming of somatic cells into induced pluripotent stem cells (iPSC) remains controversial. Some reports suggest that Mbd3 inhibits pluripotency, whilst others show that it greatly enhances reprogramming efficiency. Our study is the first to assess the role of Mbd3 on reprogramming of primary human fibroblasts using Yamanaka episomal plasmids (Reprogramming factors (RF) under feeder-free conditions. We showed that shRNA-mediated partial depletion of Mbd3 resulted in >5-fold reduction in the efficiency of reprogramming of primary human fibroblasts. Furthermore, iPSC that emerged after knock-down of Mbd3 were incapable of trilineage differentiation even though they expressed all markers of pluripotency. In contrast, over-expression of the Mbd3b isoform along with the Yamanaka episomal plasmids increased the number of fibroblast derived iPSC colonies by at least two-fold. The resulting colonies were capable of trilineage differentiation. Our results, therefore, suggest that Mbd3 appears to play an important role in reprogramming of primary human fibroblasts, which provides further insight into the biology of reprogramming but also has direct implication for translation of iPSC to clinic

    Comparison of Secreted Frizzled-Related Protein -4 & -5 Promoter Methylation in Patients with Acute Myeloblastic Leukemia and Healthy Individuals

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    Background: DNA methylation patterns are often changed in cancer cells. Many of the tumor inhibitor genes are silenced by methylation, such as CDKN2B, p73, and the suppressor of cytokine signaling in patients with acute myeloblastic leukemia (AML). Secreted frizzled-related protein -4 and -5 (SFRP4, 5) are negative regulators of the Wnt signaling pathway. We aimed to evaluate the methylation status of SFRP4 and SFRP5 genes in patients with AML. Methods: Blood samples were isolated from 60 patients with AML and 30 healthy controls. DNA was exploited, treated with sodium bisulfite, and tested utilizing methylation-specific polymerase chain reaction with specific primers for methylated and unmethylated sequences of the SFRP4 and SFRP5 genes. Results: The frequency of unfit hypermethylation of SFRP4 and SFRP5 genes in patients with AML was characterized to be 50% (30/60) and 40% (24/60), respectively. Moreover, for all the subjects in the control group, methylation of SFRP4 and SFRP5 genes was negative. The spread of SFRP4 and SFRP5 promoter methylation in patients with AML was higher than the control population. Conclusion: Hypermethylation was seen in SFRP4 and SFRP5 genes in patients with AML
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