5,245 research outputs found

    Imipenem resistance in clinical Escherichia coli from Qom, Iran

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    OBJECTIVE: The emergence of metallo-\u3b2-lactamase-producing Enterobacteriaceae is a worldwide health concern. In this study, the first evaluation of MBL genes, bla IMP and bla VIM , in Escherichia coli resistant to imipenem isolated from urine and blood specimens in Qom, Iran is described. Three hundred urine and blood specimens were analysed to detect the presence of E. coli. Resistance to imipenem and other antimicrobials was determined by disk diffusion and MIC. MBL production was screened using CDDT. PCR was also carried out to determine the presence of bla IMP and bla VIM genes in imipenem-resistant isolates. RESULTS: In total, 160 E. coli isolates were collected from March to May 2016. According to disk diffusion, high-level of resistance (20%) to cefotaxime was observed, whereas the lowest (1%) was detected for tetracycline. In addition, five isolates showed resistance to imipenem with a MIC\u2009 65\u20094 \ub5g/mL. CDDT test confirmed that five isolates were MBL-producing strains, but no bla IMP and bla VIM genes were detected. Results of this study show a very low level of resistance to imipenem in our geographical area

    Optical properties of Born-Infeld-dilaton-Lifshitz holographic superconductors

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    In this paper, we first study the Lifshitz-dilaton holographic superconductors with nonlinear Born-Infeld (BI) gauge field and obtain the critical temperature of the system for different values of Lifshitz dynamical exponent, zz, and nonlinear parameter bb. We find that for fixed value of bb, the critical temperature decreases with increasing zz. This indicates that the increase of anisotropy between space and time prevents the phase transition. Also, for fixed value of zz, the critical temperature decrease with increasing bb. Then, we investigate the optical properties of (2+12+1) and (3+13+1)-dimensional BI-Lifshitz holographic superconductors in the the presence of dilaton field. We explore the refractive index of the system. For z=1z=1 and (2+1)(2+1)-dimensional holographic superconductor, we observe negative real part for permittivity Re[ϵ]\textrm{Re}[\epsilon] as frequency ω\omega decreases. Thus, in low frequency region our superconductor exhibit metamaterial property. This behaviour is independent of the nonlinear parameter and can be seen for either linear (b=0b=0) and nonlinear (b≠0b\neq 0) electrodynamics. Interestingly, for (3+13+1)-dimensional Lifshitz-dilaton holographic superconductors, we observe metamaterial behavior neither in the presence of linear nor nonlinear electrodynamics.Comment: 11 pages, 9 figures (including subfigures), some references added in V

    Prefabrication in the UK housing construction industry

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    This paper aims to explore how prefabricated methods of construction could address housing shortages in the UK. The available literature is reviewed to evaluate current conditions of housing as well as prefabricated methods of construction in the UK. Advantages and limitations of prefabrication are investigated and discussed in relation to the current conditions. Interviews are also conducted as well as case studies in order to understand the challenges and to provide first hand information on current industry practises in the UK housing construction industry. Findings indicate that although offsite construction is widely known and acknowledged, there is little encouragement and incentives to maximise the use of prefabrication in the UK. Extra costs, larger lead time and engineering issues are found to be the key factors preventing the innovative processes of prefabricated construction in the UK’s residential sector

    Improved Bond Stress-Slip Relationships for CFRP-Strengthened Masonry Triplets

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    Carbon fibre-reinforced polymer (CFRP) emerges as a viable solution for reinforcing unreinforced masonry (URM) walls subjected to shear loads. While masonry structures are straightforward to construct, the complexity of the construction materials, especially in terms of their mechanical properties, poses challenges for numerical studies of their structural behaviour. Walls, being fundamental components in masonry construction, play a crucial role in transferring both horizontal and vertical lateral forces. This study investigates the enhancement of masonry wall behaviour through the reinforcement of CFRP. CFRP reinforcement increases ductility and strength, reducing the risk of failure under shear conditions. Additionally, CFRP composites present a practical solution to strengthening masonry structures compared to traditional reinforcement. However, brick, mortar, and CFRP have not been thoroughly investigated. Experimental tests on the bond behaviour of different configurations of CFRP-retrofitted masonry triplets have not been performed before and are therefore presented in this paper. Triplet specimens, comprising three bricks and two mortar joints, both with and without CFRP strengthening, were subjected to bond testing. The study affirms that masonry triplets strengthened with CFRP under shear loads exhibit strength levels at least four to six times greater than those without CFRP. The experimental work was carried out with eight different CFRP configurations on triplet masonry, and each test was repeated four times. Further, the bond stress-slip relationship in the case of masonry triplets with and without CFRP was predicted with new mathematical equations based on the conducted test results. These equations were included in the commercial finite element software ANSYS and used to conduct simulations of CFRP-reinforced masonry triplets. The numerical results indicate good agreement between the finite element model and the test results. The outcome of this research improves the current knowledge on the use of CFRP to reinforce masonry walls with brick and mortar, which will contribute to the understanding of the effect of CFRP on masonry structures.The outcome of this research improves the current knowledge on the use of CFRP to reinforce masonry walls with brick and mortar, which will contribute to the understanding of the effect of CFRP on masonry structures

    GB virus C viremia and anti-E2 antibody response among hemodialysis patients in Gorgan, Iran

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    Background: GB Virus C is a blood-borne virus and a member of Flaviviridae, like hepatitis C that is distributed globally and puts hemodialysis patients at high risk of developing liver disease. The clinical significance of GBV-C in this population remains unclear

    Effects of Manual and Automatic Natural Ventilation Control Strategies on Thermal Comfort, Indoor Air Quality and Energy Consumption

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    Occupants of naturally ventilated buildings can tolerate wider ranges of temperature and Indoor Air Quality (IAQ) if they have more control over their environment. Meanwhile, due to the complexity of advanced natural ventilation (ANV) strategies, introducing some form of automatic control is essential despite the fact that they limit the occupants’ control over their environment. Therefore, it is essential to understand the performance of ANV systems and occupants’ behaviours in order to identify a balance between automatic and manual controls to enhance the performance of ANV systems while maintaining the occupants’ comfort. The aim of the work reported in this paper is to evaluate the effects of a retrofitted ANV system with manual and automatic controls on thermal comfort, indoor air quality and energy consumption in an open-plan office building in the UK. Physical measurements were used to study the building performance in terms of thermal comfort, IAQ and energy consumption. The results revealed that occupants were much more aware about thermal comfort compared to IAQ. Therefore, relying on the occupants to control the ventilation system would considerably increase the risk of poor IAQ in buildings. Moreover, introducing automatic controls did not affect the thermal comfort conditions for those who understood and actively controlled the ANV system, while the situation improved for those occupants who were not active. Results of this study showed that introducing automated natural ventilation helped to reduce energy consumption by 8%

    Investigation of the impact of excavation (reinforced) on the seismic behavior of adjacent steel structures under the influence of near-fault and far-fault earthquakes

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    Every year, as a result of earthquake, abundant losses may be created as result of roof motion and sliding and rupture. Under normal conditions, the ground and soils forming the ground tolerate and transfer the existing stresses and any kind of action like excavation and release of trench and applying dynamic load could distort the balance of stresses and endanger stability of roof. In this study, behavior of a steel building in adjacency of excavation is studied. The pit is stabled using hybrid system of pinching and anchoring and is studied before and after excavation under the effect of far and near-fault earthquakes with regard to soil-structure interaction. The results obtained from nonlinear dynamic analysis of time history of two said spectrums showed that the momentum of floor in the structure after excavation is increased compared to the time before excavation. The momentum of floor in the desired structure in near-fault earthquake has been increased compared to far-fault earthquake before excavation compared to the time after excavation. However, the overall drift of floors in the structure before excavation in near-fault earthquakes has been increased more than far-fault earthquakes.Keywords: excavation, earthquake, far and near-fault zone, dynamic behavior, soil-structure interaction, steel structur

    The Effect of Massage With Lavender Oil on Restless Leg Syndrome in Hemodialysis Patients: A Randomized Controlled Trial

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    Background: Restless leg syndrome (RLS) is a common problem in patients with chronic renal failure. It can reduce the quality of life and sleep disturbances. This disorder is usually treated pharmacologically. Recently, complementary medicine methods have been suggested because of chemical drugs adverse effects. There is not enough evidence about the effect of aromatherapy on RLS. Objectives: The aim of this study was to determine the effects of massage with lavender oil on RLS symptoms in hemodialysis patients. Patients and Methods: This randomized clinical trial study included 70 hemodialysis patients with RLS that were randomly assigned into two groups in 2014. The experimental group received effleurage massage using lavender oil and control group received routine care for three weeks. Data was collected with RLS questionnaire and analyzed using independent and paired t-test and Chi-square test. Results: The mean RLS scores were not significantly different in the two groups at the start of study (22.41 ± 7.67 vs. 22.90 ± 4.38, P = 0.76). At the end of study, the mean RLS score significantly decreased in the intervention group, while this score remained relatively un-changed in the control group (12.41 ± 5.49 vs. 23.23 ± 4.52, P < 0.0001). Conclusions: Lavender oil massage was effective to improve RLS in hemodialysis patients. It has no adverse effects, is practical and cost-effective. It is suggested to be used along with routine treatment of RLS in hemodialysis patients

    A dynamical law for slow crack growth in polycarbonate films

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    We study experimentally the slow growth of a single crack in polycarbonate films submitted to uniaxial and constant imposed stress. For this visco-plastic material, we uncover a dynamical law that describes the dependence of the instantaneous crack velocity with experimental parameters. The law involves a Dugdale-Barenblatt static description of crack tip plastic zones associated to an Eyring's law and an empirical dependence with the crack length that may come from a residual elastic field
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