244 research outputs found

    Parameters Analysis of Crude Oil Transport with Pipes

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    The paper provides an analysis of key parameters such as: heat transfer coefficients, flow, pressure drop, pump power, heat losses and temperature drop in the oil pipeline. Tests were performed on a real oil pipeline plant with a diameter of 457 mm and a length of 91000 m. The oil pipeline is dig into the ground at a depth of 1.5 m. As an experimental fluid, crude oil of the paraffinic type, with a pour point of +8 to +26 oC, was used. In order to improve transport properties and prevent the appearance of paraffin inside the pipeline, the crude oil was heated to a temperature in the range of +20 to +50 oC. Origin software was used to display the research results. An analysis of the key transport parameters and their mutual dependencies and influences is also given. The aim of the work is to analyze and determine the optimal parameters of crude oil transport, as well as to determine the relation between heating temperature, paraffin content, flow temperature and cooling rate, where oil solid content will not occur. For such research, paraffin type oil was chosen as the experimental fluid

    Costs and economic evaluations of Quality Improvement Collaboratives in healthcare: a systematic review

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    BACKGROUND:In increasingly constrained healthcare budgets worldwide, efforts to improve quality and reduce costs are vital. Quality Improvement Collaboratives (QICs) are often used in healthcare settings to implement proven clinical interventions within local and national programs. The cost of this method of implementation, however, is cited as a barrier to use. This systematic review aims to identify and describe studies reporting on costs and cost-effectiveness of QICs when used to implement clinical guidelines in healthcare. METHODS:Multiple databases (CINAHL, MEDLINE, PsycINFO, EMBASE, EconLit and ProQuest) were searched for economic evaluations or cost studies of QICs in healthcare. Studies were included if they reported on economic evaluations or costs of QICs. Two authors independently reviewed citations and full text papers. Key characteristics of eligible studies were extracted, and their quality assessed against the Consolidated Health Economic Evaluation Reporting Standards (CHEERS). Evers CHEC-List was used for full economic evaluations. Cost-effectiveness findings were interpreted through the Johanna Briggs Institute 'three by three dominance matrix tool' to guide conclusions. Currencies were converted to United States dollars for 2018 using OECD and World Bank databases. RESULTS:Few studies reported on costs or economic evaluations of QICs despite their use in healthcare. Eight studies across multiple healthcare settings in acute and long-term care, community addiction treatment and chronic disease management were included. Five were considered good quality and favoured the establishment of QICs as cost-effective implementation methods. The cost savings to the healthcare setting identified in these studies outweighed the cost of the collaborative itself. CONCLUSIONS:Potential cost savings to the health care system in both acute and chronic conditions may be possible by applying QICs at scale. However, variations in effectiveness, costs and elements of the method within studies, indicated that caution is needed. Consistent identification of costs and description of the elements applied in QICs would better inform decisions for their use and may reduce perceived barriers. Lack of studies with negative findings may have been due to publication bias. Future research should include economic evaluations with societal perspectives of costs and savings and the cost-effectiveness of elements of QICs. TRIAL REGISTRATION:PROSPERO registration number: CRD42018107417.Lenore de la Perrelle, Gorjana Radisic, Monica Cations, Billingsley Kaambwa, Gaery Barbery and Kate Lave

    How, why and under what circumstances does a quality improvement collaborative build knowledge and skills in clinicians working with people with dementia? A realist informed process evaluation

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    In increasingly constrained health and aged care services, strategies are needed to improve quality and translate evidence into practice. In dementia care, recent failures in quality and safety have led the WHO to prioritise the translation of known evidence into practice. While quality improvement collaboratives have been widely used in healthcare, there are few examples in dementia care. We describe a recent quality improvement collaborative to improve dementia care across Australia and assess the implementation outcomes of acceptability and feasibility of this strategy to translate known evidence into practice. A realist-informed process evaluation was used to analyse how, why and under what circumstances a quality improvement collaborative built knowledge and skills in clinicians working in dementia care. This realist-informed process evaluation developed, tested and refined the programme theory of a quality improvement collaborative. Data were collected pre-intervention and post-intervention using surveys and interviews with participants (n=28). A combined inductive and deductive data analysis process integrated three frameworks to examine the context and mechanisms of knowledge and skill building in participant clinicians. A refined program theory showed how and why clinicians built knowledge and skills in quality improvement in dementia care. Six mechanisms were identified: motivation, accountability, identity, collective learning, credibility and reflective practice. These mechanisms, in combination, operated to overcome constraints, role boundaries and pessimism about improved practice in dementia care. A quality improvement collaborative designed for clinicians in different contexts and roles was acceptable and feasible in building knowledge, skills and confidence of clinicians to improve dementia care. Supportive reflective practice and a credible, flexible and collaborative process optimised quality improvement knowledge and skills in clinicians working with people with dementia.Lenore de la Perrelle, Monica Cations, Gaery Barbery, Gorjana Radisic, Billingsley Kaambwa, Maria Crotty, Janna Anneke Fitzgerald, Susan Kurrle, Ian Cameron, Craig Whitehead, Jane Thompson, Kate Lave

    Demonstration of a Submillimeter-Wave HEMT Oscillator Module at 330 GHz

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    In this work, radial transitions have been successfully mated with a HEMT-based MMIC (high-electron-mobility-transistor-based monolithic microwave integrated circuit) oscillator circuit. The chip has been assembled into a WR2.2 waveguide module for the basic implementation with radial E-plane probe transitions to convert the waveguide mode to the MMIC coplanar waveguide mode. The E-plane transitions have been directly integrated onto the InP substrate to couple the submillimeter-wave energy directly to the waveguides, thus avoiding wire-bonds in the RF path. The oscillator demonstrates a measured 1.7 percent DC-RF efficiency at the module level. The oscillator chip uses 35-nm-gate-length HEMT devices, which enable the high frequency of oscillation, creating the first demonstration of a packaged waveguide oscillator that operates over 300 GHz and is based on InP HEMT technology. The oscillator chip is extremely compact, with dimensions of only 1.085 x 320 sq mm for a total die size of 0.35 sq mm. This fully integrated, waveguide oscillator module, with an output power of 0.27 mW at 330 GHz, can provide low-mass, low DC-power-consumption alternatives to existing local oscillator schemes, which require high DC power consumption and large mass. This oscillator module can be easily integrated with mixers, multipliers, and amplifiers for building high-frequency transmit and receive systems at submillimeter wave frequencies. Because it requires only a DC bias to enable submillimeter wave output power, it is a simple and reliable technique for generating power at these frequencies. Future work will be directed to further improving the applicability of HEMT transistors to submillimeter wave and terahertz applications. Commercial applications include submillimeter-wave imaging systems for hidden weapons detection, airport security, homeland security, and portable low-mass, low-power imaging system

    Difference of clinical features in childhood Mycoplasma pneumoniae pneumonia

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    <p>Abstract</p> <p>Background</p> <p><it>M. pneumoniae </it>pneumonia (MP) has been reported in 10-40% of community-acquired pneumonia cases. We aimed to evaluate the difference of clinical features in children with MP, according to their age and chest radiographic patterns.</p> <p>Methods</p> <p>The diagnosis of MP was made by examinations at both admission and discharge and by two serologic tests: the indirect microparticle agglutinin assay (≥1:40) and the cold agglutinins titer (≥1:32). A total of 191 children with MP were grouped by age: ≤2 years of age (29 patients), 3-5 years of age (81 patients), and ≥6 years of age (81 patients). They were also grouped by pneumonia pattern: bronchopneumonia group (96 patients) and segmental/lobar pneumonia group (95 patients).</p> <p>Results</p> <p>Eighty-six patients (45%) were seroconverters, and the others showed increased antibody titers during hospitalization. Among the three age groups, the oldest children showed the longest duration of fever, highest C-reactive protein (CRP) values, and the most severe pneumonia pattern. The patients with segmental/lobar pneumonia were older and had longer fever duration and lower white blood cell (WBC) and lymphocyte counts, compared with those with bronchopneumonia. The patient group with the most severe pulmonary lesions had the most prolonged fever, highest CRP, highest rate of seroconverters, and lowest lymphocyte counts. Thrombocytosis was observed in 8% of patients at admission, but in 33% of patients at discharge.</p> <p>Conclusions</p> <p>In MP, older children had more prolonged fever and more severe pulmonary lesions. The severity of pulmonary lesions was associated with the absence of diagnostic IgM antibodies at presentation and lymphocyte count. Short-term paired IgM serologic test may be mandatory for early and definitive diagnosis of MP.</p

    Maternal hypoxia decreases capillary supply and increases metabolic inefficiency leading to divergence in myocardial oxygen supply and demand

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    Maternal hypoxia is associated with a decrease in left ventricular capillary density while cardiac performance is preserved, implying a mismatch between metabolism and diffusive exchange. We hypothesised this requires a switch in substrate metabolism to maximise efficiency of ATP production from limited oxygen availability. Rat pups from pregnant females exposed to hypoxia (FIO2=0.12) at days 10-20 of pregnancy were grown to adulthood and working hearts perfused ex vivo. 14 C-labelled glucose and 3 H-palmitate were provided as substrates and metabolism quantified from recovery of 14CO2 and 3 H2O, respectively. Hearts of male offspring subjected to Maternal Hypoxia showed a 20% decrease in cardiac output (P<0.05), despite recording a 2-fold increase in glucose oxidation (P<0.01) and 2.5-fold increase (P<0.01) in palmitate oxidation. Addition of insulin to Maternal Hypoxic hearts, further increased glucose oxidation (P<0.01) and suppressed palmitate oxidation (P<0.05), suggesting preservation in insulin signalling in the heart. In vitro enzyme activity measurements showed that Maternal Hypoxia increased both total and the active component of cardiac pyruvate dehydrogenase (both P<0.01), although pyruvate dehydrogenase sensitivity to insulin was lost (NS), while citrate synthase activity declined by 30% (P<0.001) and acetyl-CoA carboxylase activity was unchanged by Maternal Hypoxia, indicating realignment of the metabolic machinery to optimise oxygen utilisation. Capillary density was quantified and oxygen diffusion characteristics examined, with calculated capillary domain area increased by 30% (P<0.001). Calculated metabolic efficiency decreased 4-fold (P<0.01) for Maternal Hypoxia hearts. Paradoxically, the decline in citrate synthase activity and increased metabolism suggest that the scope of individual mitochondria had declined, rendering the myocardium potentially more sensitive to metabolic stress. However, decreasing citrate synthase may be essential to preserve local PO2, minimising regions of hypoxia and hence maximising the area of myocardium able to preserve cardiac output following maternal hypoxia

    Bioreactors as engineering support to treat cardiac muscle and vascular disease

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    Cardiovascular disease is the leading cause of morbidity and mortality in the Western World. The inability of fully differentiated, load-bearing cardiovascular tissues to in vivo regenerate and the limitations of the current treatment therapies greatly motivate the efforts of cardiovascular tissue engineering to become an effective clinical strategy for injured heart and vessels. For the effective production of organized and functional cardiovascular engineered constructs in vitro, a suitable dynamic environment is essential, and can be achieved and maintained within bioreactors. Bioreactors are technological devices that, while monitoring and controlling the culture environment and stimulating the construct, attempt to mimic the physiological milieu. In this study, a review of the current state of the art of bioreactor solutions for cardiovascular tissue engineering is presented, with emphasis on bioreactors and biophysical stimuli adopted for investigating the mechanisms influencing cardiovascular tissue development, and for eventually generating suitable cardiovascular tissue replacements
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