519 research outputs found

    Relationship between serum level of interleukin-2 in patients with systemic lupus erythematosus and disease activity in comparison with control group

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    Background: Despite the large number of surveys, there are not any validated biomarkers for SLE disease activity till now. This study aimed to evaluate the relationship between serum level of IL-2 in patients with SLE and disease activity in comparison with control group. Materials and Methods: In this case-control study, 73 patients with lupus and 73 healthy subjects referred to the rheumatology clinic of 5 Azar Hospital in Gorgan (North of Iran).They were studied via convenience sampling during 2011-2012. Blood samples were taken from both groups and serum levels of interleukin -2 measured by Avi Bion Human IL-2 ELISA kit. Serum Level of IL-2 greater than 15 pg/ml defined positive and lesser than this amount defined negative. Disease activity evaluated with SLE disease activity index. Score greater than or equal to three or four defined as active disease. Data analysis conducted by SPSS software (version 16) and by using descriptive statistics and statistical tests. Results: Serum level of IL-2 was positive in 45.2% of sample studied and negative in 54.8% in case group, while in control group, serum level of IL-2 only in 11% of sample studied was positive and in 89% was negative. Statistical analysis indicated a significant relationship between serum level of IL-2 and the SLE disease activity index (p=0.025). Conclusion: This study showed the relationship between serum levels of IL-2 and disease activity, so this biomarker can be used as a clinical indicator for assessing disease activity in patients with SLE

    Symmetry-Adapted Phonon Analysis of Nanotubes

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    The characteristics of phonons, i.e. linearized normal modes of vibration, provide important insights into many aspects of crystals, e.g. stability and thermodynamics. In this paper, we use the Objective Structures framework to make concrete analogies between crystalline phonons and normal modes of vibration in non-crystalline but highly symmetric nanostructures. Our strategy is to use an intermediate linear transformation from real-space to an intermediate space in which the Hessian matrix of second derivatives is block-circulant. The block-circulant nature of the Hessian enables us to then follow the procedure to obtain phonons in crystals: namely, we use the Discrete Fourier Transform from this intermediate space to obtain a block-diagonal matrix that is readily diagonalizable. We formulate this for general Objective Structures and then apply it to study carbon nanotubes of various chiralities that are subjected to axial elongation and torsional deformation. We compare the phonon spectra computed in the Objective Framework with spectra computed for armchair and zigzag nanotubes. We also demonstrate the approach by computing the Density of States. In addition to the computational efficiency afforded by Objective Structures in providing the transformations to almost-diagonalize the Hessian, the framework provides an important conceptual simplification to interpret the phonon curves.Comment: To appear in J. Mech. Phys. Solid

    The Role of Microgravity in Cancer: A Dual-edge Sword

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    Since human beings could travel beyond the earth atmosphere, scientists started to investigate the effect of microgravity on human cells. Microgravity has different effects on normal and cancer cells, but the related mechanisms are not well-known till now. The aim of the present review is to focus on the consequences of exposing the cancer cells to reduced gravity. Some cancer cells organize three-dimensional structures under microgravity. Obviously, microgravity is an external stress, which can affect cell proliferation, apoptosis, cytoskeleton and signaling pathways. In addition, it touches immune-related components, regulates immune responses, and implicates immune cell activation. Low mutation aggregation and cancer rate in astronauts may lead to use microgravity as a therapeutic approach. However, it reduces the invasion and migration in some types of cancer cells, triggers the oncogenic signaling pathways including KRAS, and inhibits proliferation in normal lymphocytes. In conclusion, using microgravity as a therapeutic method in cancer treatment needs to be more investigated on both cancer and normal cells, and might not become true in the near future

    Correlation Between Low Bone Density and Disease Activity in Patients with Ulcerative Colitis

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    BACKGROUND Different clinical and epidemiological studies using dual-energy X-ray absorptiometry have shown an increased prevalence of low bone mineral density in patients with inflammatory bowel diseases. The aim of this study was to assess the correlation between bone density and the disease activity in patient swith ulcerative colitis.KEYWORDS Ulcerative colitis; Z-score; Bone densitometry; Low bone densit

    Change in bone mineral density in post menopausal women with rheumatoid arthritis

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    Introduction: Low bone mass is a serious complication of post menopausal women with rheumatoid arthritis. We determined the Change in Bone Mineral Density in postmenopausal women with rheumatoid arthritis. Methods: This retrospective cohort study was carried out on consecutive postmenopausal women with rheumatoid arthritis who were referred to the Azar 5th teaching hospital affiliated to Golestan University of Medical Sciences, North of Iran in 2009. The required data were gathered from the patients' medical records. The data were analyzed using SPSS software and statistical tests. Results: We studied 98 postmenopausal women with rheumatoid arthritis. Mean number of years since menopause and mean duration of disease were 9.39 and 5.13 respectively. T Score mean in femoral neck and lumbar spines was -1.45±1.26 and -2.45±1.44 respectively. The overall prevalence of osteoporosis at both the lumbar spine and femoral neck was 13.3. We have found a significant correlation between age, duration of disease, duration of menopause and bone mineral density (P-Value<0.01). Conlusion: Our results indicate a negative effect of age, number of years since menopause and duration of disease on bone mineral density. So, BMD should be measured in high risk women prior to the implementation of any treatment or prevention program

    Light Unmanned Aerial Vehicles (UAVs) for cooperative inspection of PV plants

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    After a fast photovoltaic (PV) expansion in the past decade supported by many governments in Europe, in this postincentive era, one of the most significant open issues in the PV sector is to find appropriate inspection methods to evaluate real PV plant performance and failures. In this context, PV modules are surely the key components affecting the overall system performance; therefore, there is a main concern about the occurrence of any kind of failure in PV modules. This paper aims to propose a novel concept for monitoring PV plants by using light unmanned aerial vehicles (UAVs) or systems (UASs) during their operation and maintenance. The main objectives of this study are to explore and evaluate the use of different UAV technologies and to propose a reliable, cost-effective, and time-saving method for the inspection of PV plants. In this research, different UAVs were employed to inspect a PV array field. For this purpose, some thermal imaging cameras and a visual camera were chosen as monitoring tools to suitably scan PV modules. The first results show that the procedure of utilizing UAV was effective in the detection of different failures of PV modules. Moreover, such a process was much faster and cost effective than traditional methods

    A review on the virtual power plant: Components and operation systems

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    © 2016 IEEE. Due to the high penetration of Distributed Generations (DGs) in the network and the presently involving competition in all electrical energy markets, Virtual Power Plant (VPP) as a new concept has come into view, with the intention of dealing with the increasing number of DGs in the system and handling effectively the competition in the electricity markets. This paper reviews the VPP in terms of components and operation systems. VPP fundamentally is composed of a number of DGs including conventional dispatchable power plants and intermittent generating units along with possible flexible loads and storage units. In this paper, these components are described in an all-inclusive manner, and some of the most important ones are pointed out. In addition, the most important anticipated outcomes of the two types of VPP, Commercial VPP (CVPP) and Technical VPP (TVPP), are presented in detail. Furthermore, the important literature associated with Combined Heat and Power (CHP) based VPP, VPP components and modeling, VPP with Demand Response (DR), VPP bidding strategy, and participation of VPP in electricity markets are briefly classified and discussed in this paper
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