383 research outputs found

    Thermal Energy Optimization of Building Integrated Semi-Transparent Photovoltaic Thermal Systems

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    Building integrated photovoltaic (BIPV) : The concept where the photovoltaic element assumes the function of power generation and the role of the covering component element has the potential to become one of the principal sources of renewable energy for domestic purpose. In this paper, a Building integrated semitransparent photovoltaic thermal system (BISPVT) system having fins at the back sheet of the photovoltaic module has been simulated. It has been observed that this system produces higher thermal and electrical efficiencies. The increase of wind velocity by fan system and heat exchange surface accelerates the convective heat transfer between the finned surface and the fluid flowing in the duct. The system area of 36.45 m2 is capable of annually producing an amount of thermal energy of 76.66 kWh at an overall thermal efficiency of 56.07 %

    The DFT+U: Approaches, Accuracy, and Applications

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    This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials

    Intra and extraarticular localized pigmented villonodular synovitis

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    A 28 year old woman had a history of knee trauma and presented with unilateral knee acute swelling and pain symptoms with sudden onset, which was there from last 2 years. She had been treated for seronegative rheumatoid patient for 1 year. Recent expansion of the LPVNS (localized pigmented villonodular synovitis) caused the development of a tender palpable soft tissue mass in the anterolateral aspect of the knee and acute reduced mobility. Preoperative magnetic resonance imaging of the knee revealed the presence of only the soft tissue mass and mild degenerative changes. Open synovectomy was performed successfully to excise the mass. Intraoperatively, macroscopic features of the bright brown inflamed synovium suggested LPVNS, which was confirmed histopathologically. Postoperatively, the symptoms of limited mobility and pain were appreciably relieved. Recurrence was not observed during the clinical follow up at 1, 6 or 18 months after surgery. Here, we reported the unique case of localized pigmented villonodular synovitis of the knee in a misdiagnosed patient with intra and extraarticular lesion, which might be attributed to the history of knee trauma and the focal defect of the lateral patellar retinaculum. Open synovectomy effectively relieved the symptoms of limited mobility and pain and no recurrence was observed prior to 18 months postoperatively. To reduce misdiagnosis, MRI examinations are recommended for all patients suspected of having PVNS, including those who have a history of hyperuricemia

    An acridine derivative, [4,5-bis{(N-carboxy methyl imidazolium)methyl}acridine] dibromide, shows anti-TDP-43 aggregation effect in ALS disease models

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    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease associated with aggregation of TAR DNA-binding protein-43 (TDP-43) in neuronal cells and manifests as motor neuron dysfunction & muscle atrophy. The carboxyl-terminal prion-like domain of TDP-43 can aggregate in vitro into toxic β-sheet rich amyloid-like structures. So far, treatment options for ALS are very limited and Riluzole, which targets glutamate receptors, is the only but highly ineffective drug. Therefore, great interest exists in developing molecules for ALS treatment. Here, we have examined certain derivatives of acridine containing same side chains at position 4 & 5, for inhibitory potential against TDP-43 aggregation. Among several acridine derivatives examined, AIM4, which contains polar carboxyl groups in the side arms, significantly reduces TDP-43-YFP aggregation in the powerful yeast model cell and also abolishes in vitro amyloid-like aggregation of carboxyl terminal domain of TDP-43, as observed by AFM imaging. Thus, AIM4 can be a lead molecule potentiating further therapeutic research for ALS

    Decreased Level of Vitamin D is Associated with Rheumatoid Arthritis Patients from Western Region of Nepal

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    Background: Rheumatoid Arthritis (RA) is a progressive, chronic type of autoimmune disease and the role of vitamin D in the pathogenesis of RA is under investigation. Objective: The objective of this study was to determine the vitamin D deficiency in patients with RA as compared to healthy controls and to assess the relationship between serum vitamin D and anti-cyclic citrullinated peptide (anti-CCP) antibody levels in patients with newly diagnosed rheumatoid arthritis. Methods: The study was conducted between January 2017 to February 2018 at Fishtail Hospital and Research centre. A total of 63 patients with early RA diagnosed and a control group of 56 healthy participants, not on vitamin D supplements were recruited from Department of Internal Medicine. Five ml of blood samples were drawn from cubital veins. Blood glucose, creatinine, uric acid, calcium, RA factor, 25-hydroxy vitamin D, anti-CCP antibody, and erythrocyte sedimentation rates were measured in a centralized laboratory of Fishtail Hospital and Research centre. Results: The level of serum 25-hydroxy vitamin D were significantly lower in RA group (20.03 ±9.97 ng/mL) in comparison to the control group (24.46 ±8.45 ng/mL) (p<0.003). Our result indicates the prevalence of vitamin D deficiency was more in RA group compared with control group (47.61% vs. 33.16%, p <0.002). The level of Anti-CCP is significantly high in RA group than control group. In RA patients serum 25-hydroxy vitamin D levels were negatively correlated to anti-CCP antibody levels (rs = 0.72, p <0.001), and erythrocyte sedimentation rate (rs = 3.95, p <0.005). Conclusion: In RA patient vitamin D deficiency is quite common and serum 25-hydroxy vitamin D level was negatively correlated to anti-CCP antibody level. Our results suggest that vitamin D level is a motivation factor rather than a consequence of RA activity

    Effect of FSW Parameters on The Microstructure and Mechanical Properties of T-joints between Dissimilar Al-Alloys

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    The main purpose of this research is to develop T-joints between the aluminum AA 2024-T4 and AA 7075-T6 using friction stir welding.&nbsp; The effect of tool geometries, tool traveling speed, and rotational rate in the welded T-joints were investigated and discussed. Three different tools were used with different shoulder to pin ratios 3.28, 3.36, and 4.31. After optimization, the best tool dimension has used with the different rotational and welding speeds. Three tool traverse speeds of 50, 75, and 100 mm/min were used. Two rotation rates of 800 rpm and 1000 rpm were applied. After FSW, at a number of the above FSW parameters' combinations, macrostructure and microstructure analyses were done using optical microscopy. In order to have an insight into the mechanical properties, hardness measurements and tensile testing were carried out. Using small shoulder to pin ratio produced visually unacceptable T-joint. Opposite happened by using the tool with 4.31 of shoulder to pin ratio. Furthermore, the results showed sound T-welds with no obvious defects at high rotational rate of 1000 rpm with the two used traveling speeds. Asymmetric temperature distribution was observed between the two sides, advance side (AS) and retreating side (RS

    A Protocol of Using White/Red Color Assay to Measure Amyloid-induced Oxidative Stress in Saccharomyces cerevisiae

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    The yeast Saccharomyces cerevisiae (S. cerevisiae) harboring ade1 or ade2 mutations manifest red colony color phenotype on rich yeast medium YPD. In these mutants, intermediate metabolites of adenine biosynthesis pathway are accumulated. Accumulated intermediates, in the presence of reduced glutathione, are transported to the vacuoles, whereupon the development of the red color phenotype occurs. Here, we describe a method to score for presence of oxidative stress upon expression of amyloid-like proteins that would convert the red phenotype of ade1/ade2 mutant yeast to white. This assay could be a useful tool for screening for drugs with anti-amyloid aggregation or anti-oxidative stress potency
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