910 resultados para elastomeric infusion pump


Relevância:

20.00% 20.00%

Publicador:

Resumo:

This material is based upon work supported by the National Science Foundation through the Florida Coastal Everglades Long-Term Ecological Research program under Cooperative Agreements #DBI-0620409 and #DEB-9910514. This image is made available for non-commercial or educational use only.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The search for new materials especially those possessing special properties continues at a great pace because of ever growing demands of the modern life. The focus on the use of intrinsically conductive polymers in organic electronic devices has led to the development of a totally new class of smart materials. Polypyrrole (PPy) is one of the most stable known conducting polymers and also one of the easiest to synthesize. In addition, its high conductivity, good redox reversibility and excellent microwave absorbing characteristics have led to the existence of wide and diversified applications for PPy. However, as any conjugated conducting polymer, PPy lacks processability, flexibility and strength which are essential for industrial requirements. Among various approaches to making tractable materials based on PPy, incorporating PPy within an electrically insulating polymer appears to be a promising method, and this has triggered the development of blends or composites. Conductive elastomeric composites of polypyrrole are important in that they are composite materials suitable for devices where flexibility is an important parameter. Moreover these composites can be moulded into complex shapes.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Resistance-Nodulation-Division (RND) efflux pumps are responsible for multidrug resistance in Pseudomonas aeruginosa. In this study, we demonstrate that CpxR, previously identified as a regulator of the cell envelope stress response in Escherichia coli, is directly involved in activation of expression of RND efflux pump MexAB-OprM in P. aeruginosa. A conserved CpxR binding site was identified upstream of the mexA promoter in all genome-sequenced P. aeruginosa strains. CpxR is required to enhance mexAB-oprM expression and drug resistance, in the absence of repressor MexR, in P. aeruginosa strains PA14. As defective mexR is a genetic trait associated with the clinical emergence of nalB-type multidrug resistance in P. aeruginosa during antibiotic treatment, we investigated the involvement of CpxR in regulating multidrug resistance among resistant isolates generated in the laboratory via antibiotic treatment and collected in clinical settings. CpxR is required to activate expression of mexAB-oprM and enhances drug resistance, in the absence or presence of MexR, in ofloxacin-cefsulodin-resistant isolates generated in the laboratory. Furthermore, CpxR was also important in the mexR-defective clinical isolates. The newly identified regulatory linkage between CpxR and the MexAB-OprM efflux pump highlights the presence of a complex regulatory network modulating multidrug resistance in P. aeruginosa.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the last years the need to develop more environmentally friendly and efficient cars as led to the development of several technologies to improve the performance of internal combustion engines, a large part of the innovations are focused in the auxiliary systems of the engine, including, the oil pump, this is an element of great importance in the dynamics of the engine as well a considerable energy consumer. Most solutions for oil pumps to this day are fixed displacement, for medium and high speeds, the pump flow rate is higher than the needs of the engine, this excess flow leads to the need for recirculation of the fluid which represents a waste of energy. Recently, technological advances in this area have led to the creation of variable displacement oil pumps, these have become a 'must have' due to the numerous advantages they bring, although the working principle of vane or piston pumps is relatively well known, the application of this technology for the automotive industry is new and brings new challenges. The focus of this dissertation is to develop a new concept of variable displacement system for automotive oil pumps. The main objective is to obtain a concept that is totally adaptable to existing solutions on the market (engines), both dimensionally as in performance specifications, having at the same time an innovative mechanical system for obtaining variable displacement. The developed design is a vane pump with variable displacement going in line with existing commercial solutions, however, the variation of the eccentricity commonly used to provide an variable displacement delivery is not used, the variable displacement is achieved without varying the eccentricity of the system but with a variation of the length of the pumping chamber. The principle of operation of the pump is different to existing solutions while maintaining the ability to integrate standard parts such as control valves and mechanical safety valves, the pump is compatible with commercial solutions in terms of interfaces for connection between engine systems and pump. A concept prototype of the product was obtained in order to better evaluate the validity of the concept. The developed concept represents an innovation in oil pumps design, being unique in its mechanical system for variable displacement delivery.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Life Cycle Climate Performance (LCCP) is an evaluation method by which heating, ventilation, air conditioning and refrigeration systems can be evaluated for their global warming impact over the course of their complete life cycle. LCCP is more inclusive than previous metrics such as Total Equivalent Warming Impact. It is calculated as the sum of direct and indirect emissions generated over the lifetime of the system “from cradle to grave”. Direct emissions include all effects from the release of refrigerants into the atmosphere during the lifetime of the system. This includes annual leakage and losses during the disposal of the unit. The indirect emissions include emissions from the energy consumption during manufacturing process, lifetime operation, and disposal of the system. This thesis proposes a standardized approach to the use of LCCP and traceable data sources for all aspects of the calculation. An equation is proposed that unifies the efforts of previous researchers. Data sources are recommended for average values for all LCCP inputs. A residential heat pump sample problem is presented illustrating the methodology. The heat pump is evaluated at five U.S. locations in different climate zones. An excel tool was developed for residential heat pumps using the proposed method. The primary factor in the LCCP calculation is the energy consumption of the system. The effects of advanced vapor compression cycles are then investigated for heat pump applications. Advanced cycle options attempt to reduce the energy consumption in various ways. There are three categories of advanced cycle options: subcooling cycles, expansion loss recovery cycles and multi-stage cycles. The cycles selected for research are the suction line heat exchanger cycle, the expander cycle, the ejector cycle, and the vapor injection cycle. The cycles are modeled using Engineering Equation Solver and the results are applied to the LCCP methodology. The expander cycle, ejector cycle and vapor injection cycle are effective in reducing LCCP of a residential heat pump by 5.6%, 8.2% and 10.5%, respectively in Phoenix, AZ. The advanced cycles are evaluated with the use of low GWP refrigerants and are capable of reducing the LCCP of a residential heat by 13.7%, 16.3% and 18.6% using a refrigerant with a GWP of 10. To meet the U.S. Department of Energy’s goal of reducing residential energy use by 40% by 2025 with a proportional reduction in all other categories of residential energy consumption, a reduction in the energy consumption of a residential heat pump of 34.8% with a refrigerant GWP of 10 for Phoenix, AZ is necessary. A combination of advanced cycle, control options and low GWP refrigerants are necessary to meet this goal.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Campylobacter is a major cause of acute bacterial gastroenteritis worldwide, with the highest number of infections being attributed to Campylobacter jejuni. C. jejuni is a Gram negative, spiral, motile bacterium that belongs to the campylobacterales order and is related to both Helicobacter spp. and Wolinella sp.. It has long been established that proton pump inhibitors (PPIs) and other benzimidazole derivatives display anti-Helicobacter activity in vitro. PPIs have in the past been shown to affect Helicobacter pylori growth, survival, motility, morphology, adhesion/invasion potential and susceptibility to conventional antibiotics. PPIs are highly effective drugs that are well tolerated, safe for prolonged daily use and are therefore in high demand. Both the PPIs omeprazole and lansoprazole featured in the top ten drugs prescribed in England in 2014. In 2014 Campylobacter was also the most commonly diagnosed gastrointestinal infection in Scotland, in England and Wales and also in Europe. It has previously been generally accepted that patients who are being treated with PPIs are more susceptible to enteric infections such as Campylobacter than people not taking PPIs. The effect of PPI exposure on H. pylori has been investigated rigorously in the past. A single previous study has hinted that PPIs may also be capable of affecting the related organism C. jejuni,but investigations have been extremely limited in comparison to those investigating the effect of PPIs on H. pylori. This study has investigated the in vitro effects of direct contact with PPIs on the biology ofC. jejuni. Exposure to the PPI pantoprazole was found to affect C. jejuni growth/survival, motility, morphology, biofilm formation, invasion potential and susceptibility to some conventional antibiotics. Microarray studies showed that the cmeA and Cj0561c genes were significantly up-regulated in response to pantoprazole exposure and a CmeABC deficient mutant was found to be significantly more susceptible to killing by pantoprazole than was the parent strain. Proteomic analysis indicated that the oxidative stress response of C. jejuni was induced following exposure to sub-lethal concentrations of pantoprazole. C. jejuni gene expression was assessed using qRT-PCR and the genes encoding for thiol peroxidase and GroEL co-chaperonin (both involved in the C. jejuni oxidative stress response) were found to be around four times higher in response to exposure to sub-lethal concentrations of pantoprazole. Experiments using the oxidative stress inhibitors thiourea (a hydroxyl radical quencher) and bipyridyl (a ferrous iron chelator) showed that killing by pantoprazole was not mediated by hydroxyl radical production.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introduction: In the last few years a significant number of papers have related the use of proton-pump inhibitors (PPIs) to potential serious adverse effects that have resulted in social unrest. Objective: The goal of this paper was to provide a literature review for the development of an institutional position statement by Sociedad Española de Patología Digestiva (SEPD) regarding the safety of long-term PPI use. Material and methods: A comprehensive review of the literature was performed to draw conclusions based on a critical assessment of the following: a) current PPI indications; b) vitamin B12 deficiency and neurological disorders; c) magnesium deficiency; d) bone fractures; e) enteric infection and pneumonia; f) interactions with thienopyridine derivatives; e) complications in cirrhotic patients. Results: Current PPI indications have remained unchanged for years now, and are well established. A general screening of vitamin B12 levels is not recommended for all patients on a PPI; however, it does seem necessary that magnesium levels be measured at therapy onset, and then monitored in subjects on other drugs that may induce hypomagnesemia. A higher risk for bone fractures is present, even though causality cannot be concluded for this association. The association between PPIs and infection with Clostridium difficile is mild to moderate, and the risk for pneumonia is low. In patients with cardiovascular risk receiving thienopyridines derivatives it is prudent to adequately consider gastrointestinal and cardiovascular risks, given the absence of definitive evidence regardin potential drug-drug interactions; if gastrointestinal risk is found to be moderate or high, effective prevention should be in place with a PPI. PPIs should be cautiously indicated in patients with decompensated cirrhosis. Conclusions: PPIs are safe drugs whose benefits outweigh their potential side effects both short-term and long-term, provided their indication, dosage, and duration are appropriate.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: Spinal anaesthesia is the standard of care for elective caesarean delivery. It has advantages over general anaesthesia. However the sympathetic blockade induced by spinal anaesthesia results in an 80 percent incidence of hypotension without prophylactic management. Current evidence supports co-loading with intravenous fluids in conjunction with the use of vasopressors as the most effective way to prevent and treat the hypotension. Phenylephrine is the accepted vasopressor of choice in the parturient. A prophylactic phenylephrine infusion combined with a fluid co-load is proven to be an effective and safe method of maintaining maternal hemodynamic stability. While most published studies have assessed the effectiveness of a prophylactic phenylephrine fixed dose infusion, few studies have assessed the effect of a prophylactic phenylephrine weight adjusted dose infusion on maintaining maternal hemodynamic stability following spinal anesthesia for a cesarean delivery. Objective: To compare the incidence of hypotension between women undergoing elective caesarean section under spinal anaesthesia, receiving prophylactic phenylephrine infusion at a fixed dose of 37.5 micrograms per minute versus a weight adjusted dose of 0.5 micrograms per kilogram per minute. Methods: One hundred and eight patients scheduled for non-urgent caesarean section under spinal anaesthesia were randomized into 2 groups; control group and intervention group using a computer generated table of numbers. Control group; Received prophylactic phenylephrine fixed dose infusion at 37.5 micrograms per minute. Intervention group; Received prophylactic phenylephrine weight adjusted dose infusion at 0.5 micrograms per kilogram per minute Results: The two groups had similar baseline characteristics in terms of ; Age, sex, weight and height. There was a 35.2% incidence of hypotension in the fixed dose group and an 18.6% incidence of hypotension in the weight adjusted dose group. This difference was found to be of borderline statistical significance p-value 0.05, and the difference in the incidence rates between the two groups was found to be statistically significant p= 0.03. The difference in the incidence of reactive hypertension and bradycardia between the two groups was not statistically significant: p-value of 0.19 for reactive hypertension and p-value of 0.42 for the incidence of bradycardia. There was also no statistically significant difference in the use of phenylephrine boluses, use of atropine, intravenous fluid used and the number of times the infusion was stopped. Conclusion: Among this population, the incidence of hypotension was significantly less in the weight adjusted dose group than in the fixed dose group. There was no difference in the number of physician interventions required to keep the blood pressure within 20% of baseline, and no difference in the proportion of reactive hypertension or bradycardia between the two groups. Administering prophylactic phenylephrine infusion at a weight adjusted dose of 0.5 micrograms per kilogram per minute results in a lower incidence of hypotension compared to its administration at a fixed dose of 37.5 micrograms per minute.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Proton-pump inhibitors (PPIs) are one of the most active ingredients prescribed in Spain. In recent decades there has been an overuse of these drugs in both outpatient clinics and hospitals that has lead to a significant increase in healthcare spending and to an increase in the risk of possible side effects. It is important for health professionals to know the accepted indications and the correct doses for the use of these drugs. On the market there are different types of PPI: omeprazole, pantoprazole, lansoprazole, rabeprazole and esomeprazole. Omeprazole is the oldest and most used PPI, being also the cheapest. Although there are no important differences between PPIs in curing diseases, esomeprazole, a new-generation PPI, has proved to be more effective in eradicating H. pylori and in healing severe esophagitis compared to other PPIs. In recent years the use of generic drugs has spread; these drugs have the same bioavailability than the original drugs. In the case of PPIs, the few comparative studies available in the literature between original and generic drugs have shown no significant differences in clinical efficacy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND: Liver transplantation-associated acute kidney injury (AKI) carries significant morbidity and mortality. We hypothesized that sodium bicarbonate would reduce the incidence and/or severity of liver transplantation-associated AKI. METHODS: In this double-blinded pilot RCT, adult patients undergoing orthotopic liver transplantation were randomized to an infusion of either 8.4% sodium bicarbonate (0.5 mEq/kg/h for the first hour; 0.15 mEq/kg/h until completion of surgery); (n = 30) or 0.9% sodium chloride (n = 30). Primary outcome: AKI within the first 48 h post-operatively.RESULTS: There were no significant differences between the two treatment groups with regard to baseline characteristics, model for end-stage liver disease and acute physiology and chronic health evaluation (APACHE) II scores, and pre-transplantation renal function. Intra-operative factors were similar for duration of surgery, blood product requirements, crystalloid and colloid volumes infused and requirements for vasoactive therapy. Eleven patients (37%) in the bicarbonate group and 10 patients (33%) in the sodium chloride group developed a post-operative AKI (p = 0.79). Bicarbonate infusion attenuated the degree of immediate post-operative metabolic acidosis; however, this effect dissipated by 48 h. There were no significant differences in ventilation hours, ICU or hospital length of stay, or mortality. CONCLUSIONS: The intra-operative infusion of sodium bicarbonate did not decrease the incidence of AKI in patients following orthotopic liver transplantation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Streptococcus suis is an emerging zoonotic agent responsible for high-mortality outbreaks among the human population in China. In this species, the ABC transporter SatAB mediates fluoroquinolone resistance when overexpressed. Here, we describe and characterize satR, an open reading frame (ORF) encoding a MarR superfamily regulator that acts as a repressor of satAB. satR is cotranscribed with satAB, and its interruption entails the overexpression of the pump, leading to a clinically relevant increase in resistance to fluoroquinolones.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Historically, domestic tasks such as preparing food and washing and drying clothes and dishes were done by hand. In a modern home many of these chores are taken care of by machines such as washing machines, dishwashers and tumble dryers. When the first such machines came on the market customers were happy that they worked at all! Today, the costs of electricity and customers’ environmental awareness are high, so features such as low electricity, water and detergent use strongly influence which household machine the customer will buy. One way to achieve lower electricity usage for the tumble dryer and the dishwasher is to add a heat pump system. The function of a heat pump system is to extract heat from a lower temperature source (heat source) and reject it to a higher temperature sink (heat sink) at a higher temperature level. Heat pump systems have been used for a long time in refrigerators and freezers, and that industry has driven the development of small, high quality, low price heat pump components. The low price of good quality heat pump components, along with an increased willingness to pay extra for lower electricity usage and environmental impact, make it possible to introduce heat pump systems in other household products. However, there is a high risk of failure with new features. A number of household manufacturers no longer exist because they introduced poorly implemented new features, which resulted in low quality and product performance. A manufacturer must predict whether the future value of a feature is high enough for the customer chain to pay for it. The challenge for the manufacturer is to develop and produce a high-performance heat pump feature in a household product with high quality, predict future willingness to pay for it, and launch it at the right moment in order to succeed. Tumble dryers with heat pump systems have been on the market since 2000. Paper I reports on the development of a transient simulation model of a commercial heat pump tumble dryer. The measured and simulated results were compared with good similarity. The influence of the size of the compressor and the condenser was investigated using the validated simulation model. The results from the simulation model show that increasing the cylinder volume of the compressor by 50% decreases the drying time by 14% without using more electricity.  Paper II is a concept study of adding a heat pump system to a dishwasher in order to decrease the total electricity usage. The dishwasher, dishware and water are heated by the condenser, and the evaporator absorbs the heat from a water tank. The majority of the heat transfer to the evaporator occurs when ice is generated in the water tank. An experimental setup and a transient simulation model of a heat pump dishwasher were developed. The simulation results show a 24% reduction in electricity use compared to a conventional dishwasher heated with an electric element. The simulation model was based on an experimental setup that was not optimised. During the study it became apparent that it is possible to decrease electricity usage even more with the next experimental setup.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Introducción: El tiempo promedio del efecto máximo de la insulina regular rápida en la glucemia postprandial ha sido considerado durante años de 120 minutos. En pacientes con Diabetes Mellitus (DM) que usan insulinas análogas este tiempo y los factores asociados no se encuentran reportados para ser aplicados en el automonitoreo. El objetivo de este estudio fue calcular el tiempo y factores relacionados al efecto máximo de la insulina en la glucemia postprandial. Metodología: Se desarrolló un estudio longitudinal retrospectivo a partir de una fuente secundaria donde se realizó un análisis descriptivo y bivariado con las variables demográficas y clínicas presentes en la población. Resultados: El tiempo promedio del pico máximo de insulina en pacientes con DM1 fue de 78.4 (DE± 16.512) y DM2 75.01(DE± 12.02) minutos. El 75% de la población con DM1 y el 54.2% en DM2 era de sexo femenino, la edad promedio en DM1 era 42.38 años y en DM2 68 años, en cuanto a la categorización del IMC el 50% de la población en DM1 y el 37.5% en DM2 estaban dentro del rango de obesidad y se encontró una relación con respecto al tipo de comida “desayuno-cena” vs el tiempo promedio del efecto máximo de la insulina calculado para ambos grupos (p:0.010). Conclusiones: El tiempo promedio del efecto máximo de la insulina calculado fue menor al tiempo reportado en la literatura clínica de 120 minutos. El tipo de comida principal mostró una relación con el tiempo promedio del efecto máximo en ambos grupos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In the early 1990's the University of Salford was typical of most pre-1992 Universities in that whilst students provided much of it's income, little attention was paid to pedagogy. As Warren Piper (1994) observed, University teachers were professional in their subject areas but generally did not seek to acquire a pedagogy of HE. This was the case in Alsford. Courses were efficiently run but only a minority of staff were engaged in actively considering learning and teaching issues. Instead staff time was spent on research and commercial activity.----- In the mid-1990's the teaching environment began to change significantly. As well as Dearing, the advent of QAA and teaching quality reviews, Salford was already experiencing changes in the characteristics of its student body. Wideing access was on our agenda before it was so predominant nationally. With increasing numbers and heterogeneity of students as well as these external factors, new challenges were facing the University and teaching domain.----- This paper describes how a culture which values teaching, learning and pedagogic inquiry is being created in the university. It then focuses on parts of this process specific to the Faculty of Business and Informatics, namely the Faculty's Learning and Teaching Research Network and the establishment of the Centre for Construction Education in the School of Construction and Property Management.----- The Faculty of Business and Informatics' Learning and Teaching Research Network aims to raise the profile, quality and volume of pedagogic research across the five schools in the faculty. The initiative is targeted at all academics regardless of previous research experience. We hope to grow and nurture research potential where it exists and to acknowledge and use the existing expertise of subject-based researchers in collaborative ventures. We work on the principle that people are deliged to share what they know but need appreciation and feedback for doing so. A further ain is to surface and celebrate the significant amount of tacit knowledge in the area of pedagogy evidenced by the strength of student and employer feedback in many areas of the faculty's teaching.----- The Faculty embraces generic and core management expertise but also includes applied management disciplines in information systems and construction and property management where internationally leading research activities and networked centres of excellence have been established. Drawing from this experience, and within the context of the Faculty network, a Centre for Construction Education is being established with key international external partners to develop a sustainable business model of an enterprising pedagogic centre that can undertake useful research to underpin teaching in the Faculty whilst offering sustainable business services to allow it to benefit from pump-priming grant funding.----- Internal and external networking are important elements in our plans and ongoing work. Key to this are our links with the LTSN subject centres (BEST and CEBE) and the LTSN generic centre. The paper discusses networking as a concept and gives examples of practices which have proved useful in this context.----- The academic influences on our approach are also examined. Dixon’s (2000) work examining how a range of companies succeed through internal knowledge sharing has provided a range of transferable practices. We also examine the notion of dialogue in this context, defined by Ballantyne (1999) as ‘The interactive human process of reasoning together which comes into being through interactions based on spontaneity or need and is enabled by trust’ Social constructionist principles of Practical Authorship (Shotter, 1993, Pavlica, Holman and Thorpe, 1998)) have also proved useful in developing our perspective on learning and knowledge creation within our community of practice.