30 research outputs found

    Non-minimal Derivative Coupling Scalar Field and Bulk Viscous Dark Energy

    Full text link
    Inspired by thermodynamical dissipative phenomena, we consider bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents Phantom crossing avoiding Big-Rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential leading to accelerated expansion of Universe in the framework of bulk viscous dark energy model. In this approach, coupling constant (κ\kappa) is related to viscosity coefficient (γ\gamma) and energy density of dark energy at the present time (ΩDE0\Omega_{\rm DE}^0). This coupling is bounded as κ∈[−1/9H02(1−ΩDE0),0]\kappa\in [-1/9H_0^2(1-\Omega_{\rm DE}^0), 0] and for γ=0\gamma=0 leads to κ=0\kappa=0. To perform robust analysis, we implement recent observational data sets including Joint Light-curve Analysis (JLA) for SNIa, Gamma Ray Bursts (GRBs) for most luminous astrophysical objects at high redshifts, Baryon Acoustic Oscillations (BAO) from different surveys, Hubble parameter from HST project, {\it Planck} data for CMB power spectrum and CMB Lensing. Joint analysis of JLA++GRBs++BAO++HST shows that ΩDE0=0.696±0.010\Omega_{\rm DE}^0=0.696\pm 0.010, γ=0.1404±0.0014\gamma=0.1404\pm0.0014 and H0=68.1±1.3H_0=68.1\pm1.3 at 1σ1\sigma confidence interval. {\it Planck} TT observation provides γ=0.32−0.26+0.31\gamma=0.32^{+0.31}_{-0.26} at 68%68\% confidence limit for viscosity coefficient. Tension in Hubble parameter is alleviated in this model. Cosmographic distance ratio indicates that current observed data prefer to increase bulk viscosity. Finally, the competition between Phantom and Quintessence behavior of viscous dark energy model can accommodate cosmological old objects reported as a sign of age crisis in Λ\LambdaCDM model.Comment: 21 pages and 18 figures, some typos in equations fixe

    Passivhaus summer overheating: the development of an effective natural ventilation system

    Get PDF
    Concern regarding overheating potential has been growing in the UK as buildings are being built to higher standards like Passivhaus. Lack of window operation due to noise and security implications specifically at night, alongside higher expected temperatures in the future can only add to this concern. Furthermore the quality of incoming fresh air through windows in Passivhaus dwellings could be lower compared to filtered air in MVHR systems. The aim of this research is to investigate the possibility of overheating in reference Passivhaus dwellings and consequently, to examine and propose a remedial natural ventilation strategy and system for the non-winter period. The internal temperatures, indoor CO2 levels alongside frequency and duration of window openings were recorded using data loggers and sensors. A dynamic thermal model was created in DesignBuilder using data from the original PHPP model and further amended by results from monitoring, creating a base case model. A specific natural ventilation system was modelled using the base case model to increase efficiency and effectiveness of natural ventilation. The proposed system was also tested for the winter period in terms of airtightness and thermal bridging as well as forecasted future climate data. The proposed system increases natural ventilation rates compared to the original design, thereby reducing summer overheating for current and future climate by around 20%. Passivhaus designers can benefit from this system for new building designs or for refurbishment of existing Passivhaus building stock that could encounter overheating in the future. The system can be tested in the PHPP calculation allowing the elimination of all window operations during the cooling season

    Airway observations during upper endoscopy predicting obstructive sleep apnea

    Get PDF
    Background This pilot study examined airway characteristics during upper endoscopy to determine who is at high risk for obstructive sleep apnea. Methods Patients undergoing routine upper endoscopy were divided into 2 groups according to the Berlin Questionnaire (high and low risk for sleep disordered breathing). Patients underwent routine upper endoscopy using propofol sedation. The airway was then evaluated for no, partial, or complete collapse at the levels of the palate/uvula/tonsils, the tongue base, the hypopharynx, and the larynx. They were given a score of 0 for no collapse, 1 for partial collapse, and 2 for complete collapse. The score for each of these levels was added to give a total score or severity index. The larynx was also evaluated for lateral pharyngeal collapse (minimal, up to 50%, >50%, or 100%). Results We found that patients with a partial obstruction at the level of the palate/uvula/tonsils, tongue base, hypopharynx, or larynx, or complete obstruction at any level more often had a positive Berlin questionnaire. Patients with a positive Berlin questionnaire were more often of increased weight (mean 197 vs 175 lbs, P=0.19), increased body mass index (31.2 vs 27.42 kg/m2, P=0.11), increased neck circumference (36.7 vs 34.7 cm, P=0.23), and had a higher total airway score (2.61 vs 1.67, P=0.09). Conclusions The results of our pilot study represent preliminary data regarding the use of upper endoscopy as a potential tool to evaluate patients for obstructive sleep apnea

    Clinical Manifestations of β-Thalassemia Major in Two Different Altitudes; Bushehr and Shahrekord

    Get PDF
    Background: Patients with β-thalassemia major (TM) develop iron overload through increased iron absorption and transfusional therapy and it’s the most important complication of TM. Thalassemia is common in coastal regions and lands with low altitudes. The aim of this study is to determine the effect of high and low altitude on serum ferritin and treatment requirement in two groups of β-thalassemia major (TM) patients. Subjects and Methods: Patients were divided into two groups, the first group (No: 50) living at sea level (in the port of Bushehr, Iran) and the second group (No: 40) living at the altitude of 2061 m (in the city of Shahrekord, Iran). All patient’s clinical history, blood transfusion and laboratory tests including complete blood count and hemoglobin electrophoresis were reviewed. Results: There were no significant difference in ferritin levels, transfusion period and diabetes incidence of the two cities patients (P>0.05). Patient’s cardiac function and liver condition were significantly better in patients of Bushehr (P<0.05). Patients under 20 years in Bushehr were less splenectomized in comparison with Shahrekord (P<0.05). Conclusion: Our result showed that some of clinical manifestations of patients in low altitude such as cardiac and liver condition were better. But it did not affect ferritin level probably due to transfusion and chelating therapy. Totally patients of Bushehr had better conditions and had longer survivals. Keywords: β-thalassemia major, Ferritin level, Cardiac function, Altitud

    TLR9-based immunotherapy for the treatment of allergic diseases

    Get PDF
    Toll-like receptors (TLRs), a family of pattern recognition receptors expressed on many cell types of innate immunity, recognize the pathogen-associated molecular patterns of microbes. The hygiene hypothesis suggests that a reduced microbial exposure in early childhood increases the susceptibility to allergic diseases due to deviation in development of the immune system. TLRs are key roles in the right and healthy direction of adaptive immunity with the induction of T-helper 2 toward Th1 immune responses and regulatory T cells. TLR ligand CpG-ODN-based immunomodulation is independent of allergen and it mainly affects innate immune system. While, CpG-oligodeoxynucleotide-based vaccination is allergen specific and induces adaptive immune system. The use of agonists of TLR9 in two distinct strategies of immunotherapy, immunomodulation and vaccination, could be presented as the curative method for the treatment of allergic diseases. First draft submitted: 29 August 2016; Accepted for publication: 8 February 2017; Published online: 17 March 2017 Keywords:  allergic diseases • immunotherapy • TLR9 • Toll-like receptor

    Serological, pathological and scintigraphic assessment of Hemiscorpius lepturus effects on renal dysfunction in rats

    Get PDF
    Objective(s): Hemiscorpius lepturus is one of the dangerous scorpions of Iran leading to acute kidney injury (AKI) especially in infants. The purpose of this animal study was to compare the serological, pathological and scintigraphic data to quickly predict the occurrence of this disorder.Materials and Methods: In two groups of animals, each contained five rats, H. lepturus venom (1200 µg/Kg) were injected intravenously via the tail vein. At three hours and one week later, 99m Tc-DMSA (3 mCi) was intravenously injected and renal scintigraphy was performed after an hour. Moreover, plasma levels of creatinine, sodium, potassium, and blood urea nitrogen (BUN) were measured. At the end of the study, renal tissues were excised and prepared to perform pathological evaluation after Hematoxylin and Eosin staining.Results: All serological indices were remained unchanged compared to control. A large number of glomerular fibrin thrombi with entrapped red blood cells and simplified tubular epithelium in dilated and ectatic tubules were observed in high power field (×100) four hours after envenomation, which reduced significantly one week later. In our scintigraphic study, there was a statistically significant difference (

    Dusty Air Pollution is Associated with an Increased Risk of Allergic Diseases in Southwestern Part of Iran

    Get PDF
    Concerns have been raised about the adverse impact of dusty air pollution (DAP) on human health. The aim of this study was to find the association between dusty air pollution based on air quality index (AQI) and the risk of allergic diseases in southwestern provinces of Iran, with assessing cytokine profiles and lymphocyte immunophenotypes. In this case control study 148 individuals participated. The sampling was done in hazardous condition (AQI >300) as the case and clean air (AQI <50) as the control. We measured cytokine production by using ELISA method and phenotypes of T-lymphocytes (CD4+ and CD8+), CD19+ B-lymphocytes, CD25+, CD4+ CD25+ cells by FACSort flow cytometer. The mean serum level of IL-4 (33.4±2.9 vs 0.85± 0.65 pg/dl) and IL-13 (15.1±4.4 vs. 0.12±0.7 pg/dl) in the subjects exposed to ambient DAP was increased significantly compared to the individuals in the clean air condition. Also, CD19+ B-lymphocytes (12.6± 4.9 vs 8.9±3.2%) and CD4+ CD25+ cell count (13.6± 4.6 vs 7.7± 3.8%) in peripheral blood were increased significantly in subjects exposed to ambient DAP compared with the controls. The result of our study suggested that ambient DAP affected immune system in a way that might lead to allergic diseases in the population

    Beneficial Effects of Exercise Training in Patients with Chronic Heart Failure

    No full text
    Several human and experimental studies have been performed to show the effects of exercise training on chronic heart failure (CHF). These studies have shown that exercise improves the adverse pathophysiologic changes which occur with CHF, including enhanced exercise capacity, ventilation, skeletal muscle metabolism, cardiac function, quality of life, and peripheral blood flow. In addition, there is an improved modulation of inflammatory, autonomic, and hormonal dysregulation after exercise training. This review focuses on the current evidence surrounding the beneficial effects of exercise training in CHF patients
    corecore