857 resultados para Internal-Friction


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Proponents of microalgae biofuel technologies often claim that the world demand of liquid fuels, about 5 trillion liters per year, could be supplied by microalgae cultivated on only a few tens of millions of hectares. This perspective reviews this subject and points out that such projections are greatly exaggerated, because (1) the pro- ductivities achieved in large-scale commercial microalgae production systems, operated year-round, do not surpass those of irrigated tropical crops; (2) cultivating, harvesting and processing microalgae solely for the production of biofuels is simply too expensive using current or prospective technology; and (3) currently available (limited) data suggest that the energy balance of algal biofuels is very poor. Thus, microalgal biofuels are no panacea for depleting oil or global warming, and are unlikely to save the internal combustion machine.

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General internal medicine (GIM) has flourished in the United States (U.S.). Unlike other subspecialties of internal medicine, however, GIM's evolution has not been global in scope, but rather appears to have occurred in isolation within countries. Here, we describe international models of GIM from Canada, Switzerland, Australia/New Zealand, Argentina, and Japan, and compare these with the U.S. model. There are notable differences in the typical clinical roles assumed by General Internists across these 7 countries, but also important overlap in clinical and academic domains. Despite this overlap, there has been a relative lack of contact among General Internists from these and other countries at a truly international GIM meeting; the time is now for increased international exchange and the "globalization" of GIM.

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Clinical practice in internal medicine has fundamentely changed over the last decade. Our knowledge has dramatically improved and we are facing new types of patients. Their number is increasing, they are older and suffer from increasingly complex medical conditions. The society has evolved as well therefore transforming our daily practice. This implies important modifications of our role and new challenges. We must also develop new aspects of our practice such as recognizing our errors, quality of care, quality of education, ethics, new strategies for taking care of the patient all this in parallel with continuous education. Our role as (general practitioner) is of utmost importance since it enables us to keep the "big pictures" in a more and more specialized environment.

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There is no definite theory yet for the mechanism by which the pattern of epidermal ridges on fingers, palms and soles forming friction ridge skin (FRS) patterns is created. For a long time growth forces in the embryonal epidermis have been believed to be involved in FRS formation. More recent evidence suggests that Merkel cells play an important part in this process as well. Here we suggest a model for the formation of FRS patterns that links Merkel cells to the epidermal stress distribution. The Merkel cells are modeled as agents in an agent based model that move anisotropically where the anisotropy is created by the epidermal stress tensor. As a result ridge patterns are created with pattern defects as they occur in real FRS patterns. As a consequence we suggest why the topology of FRS patterns is indeed unique as the arrangement of pattern defects is sensitive to the initial configuration of Merkel cells.

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This project involved the evaluation of several aggregates previously rated poor to excellent with respect to skid resistance and certain mix design parameters. An open graded asphalt friction course was evaluated using 4 comparably graded aggregates: quartzite, fine grained limestone, coarse limestone and lightweight expanded shale. The performance investigations involved the verification of observations of the quartzite test sections, evaluation of the effect of blending the superior quartzite with a typical coarse grained-textured limestone, and the evaluation of the limestone. The effects of traffic on the aggregates used in the test sections were studied, as well as the relationship between asphalt content levels and traffic with respect to performance. The bond of the open graded friction course mixture was also evaluated. The SN performance of all test sections after sixteen months of exposure was found to be satisfactory in that none of the material combinations had polished to the point where unacceptable SN levels developed. When material combinations were compared, significant differences were noted.

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The Swiss postgraduate training program in general internal medicine is now designed as a competency-based curriculum. In other words, by the end of their training, the residents should demonstrate a set of predefined competences. Many of those competences have to be learnt in outpatient settings. Thus, the primary care physicians have more than ever an important role to play in educating tomorrows doctors. A competency-based model of training requires a regular assessment of the residents. The mini-CEX (mini-Clinical Evaluation eXercise) is the assessment tool proposed by the Swiss institute for postgraduate and continuing education. The mini-CEX is based on the direct observation of the trainees performing a specific task, as well as on the ensuing feedback. This article aims at introducing our colleagues in charge of residents to the mini-CEX, which is a useful tool promoting the culture of feedback in medical education.

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This review is based on five articles published in 2006 and dealing with therapies in general internal medicine: in case of acute non complicated rhino-sinusitis, the use of topical corticoids in mono-therapy is indicated; cross-reactivity between penicillins and cephalosporins is less frequent than established so far. In our daily practice we should be more "pro-active" in prescribing probiotics which have proved their efficacy in the prevention of antibiotic-associated diarrhoeas; an antibiotic treatment of three days is recommended in case of non complicated cystitis in women less than 65 years of age. Finally, every patient treated with bisphosphonates must be regularly followed by a dentist.

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BACKGROUND: This study was designed to determine whether the pain pattern in patients with an internal mammary artery (IMA) harvest differs from that in other cardiac operations and whether these patients present specific characteristics with clinical implications. METHODS: One hundred patients with left IMA grafting (IMA group) were compared prospectively with 100 patients who had a heart operation without IMA harvest (non-IMA group). Pain assessment was performed on postoperative days (POD) 1, 2, 3, and 7, and included pain intensity (10-point scale) and pain localization. RESULTS: In the IMA group, pain intensity was higher on POD 2 (4.2 +/- 2.4 versus 3.2 +/- 2.3, p < 0.01), and there were more patients without pain on POD 7 (32 versus 19, p = 0.03). In the IMA group, more patients had left basal thoracic pain throughout the entire study period and had sternal pain on POD 7, whereas more patients in the non-IMA group complained about back pain during the early postoperative period. CONCLUSIONS: The impact of IMA harvest on pain intensity is moderate, but the pain localization pattern of each group exhibits specific features that could help to better target pain management.

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Bioassays with bioreporter bacteria are usually calibrated with analyte solutions of known concentrations that are analysed along with the samples of interest. This is done as bioreporter output (the intensity of light, fluorescence or colour) does not only depend on the target concentration, but also on the incubation time and physiological activity of the cells in the assay. Comparing the bioreporter output with standardized colour tables in the field seems rather difficult and error-prone. A new approach to control assay variations and improve application ease could be an internal calibration based on the use of multiple bioreporter cell lines with drastically different reporter protein outputs at a given analyte concentration. To test this concept, different Escherichia coli-based bioreporter strains expressing either cytochrome c peroxidase (CCP, or CCP mutants) or β-galactosidase upon induction with arsenite were constructed. The reporter strains differed either in the catalytic activity of the reporter protein (for CCP) or in the rates of reporter protein synthesis (for β-galactosidase), which, indeed, resulted in output signals with different intensities at the same arsenite concentration. Hence, it was possible to use combinations of these cell lines to define arsenite concentration ranges at which none, one or more cell lines gave qualitative (yes/no) visible signals that were relatively independent of incubation time or bioreporter activity. The discriminated concentration ranges would fit very well with the current permissive (e.g. World Health Organization) levels of arsenite in drinking water (10 µg l−1).

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Conventional concrete is typically cured using external methods. External curing prevents drying of the surface, allows the mixture to stay warm and moist, and results in continued cement hydration (Taylor 2014). Internal curing is a relatively recent technique that has been developed to prolong cement hydration by providing internal water reservoirs in a concrete mixture that do not adversely affect the concrete mixture’s fresh or hardened physical properties. Internal curing grew out of the need for more durable structural concretes that were resistant to shrinkage cracking. Joint spacing for concrete overlays can be increased if slab warping is reduced or eliminated. One of the most promising potential benefits from using internal curing for concrete overlays, then, is the reduced number of joints due to increased joint spacing (Wei and Hansen 2008).

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The prescribing of antibiotics for uncomplicated skin abscesses and diverticulitis has no benefit. Some antibiotics are more at risk of causing a Clostridium difficile infection. The tests used to exclude a history of a penicillin allergy are safe. A threshold of D-dimer adjusted for the age significantly improves the specificity of the test without affecting the sensitivity. The prescription of paraclinics tests is not an effective "treatment" for the patient's anxiety. In the sleep apnea syndrome, treatment with CPAP (Continuous positive airway pressure) appears to have more benefits compared to the mandibular advancement prosthesis. The work of primary care physicians can be supported by the work of advanced practice nurses. The limitation placed on the working hours of doctors in hospitals seems to affect their ability to spend time with their patients.