5,489 research outputs found

    Experimental investigations of the effects of cutting angle on chattering of a flexible manipulator

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    When a machine tool is mounted at the tip of a robotic manipulator, the manipulator becomes more flexible (the natural frequencies are lowered). Moreover, for a given flexible manipulator, its compliance will be different depending on feedback gains, configurations, and direction of interest. Here, the compliance of a manipulator is derived analytically, and its magnitude is represented as a compliance ellipsoid. Then, using a two-link flexible manipulator with an abrasive cut off saw, the experimental investigation shows that the chattering varies with the saw cutting angle due to different compliance. The main work is devoted to finding a desirable cutting angle which reduces the chattering

    Serotonin Syndrome after Concomitant Treatment with Linezolid and Citalopram

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    Linezolid, a new synthetic antimicrobial, is an important weapon against methicillin-resistant Staphylococcus aureus (MRSA). Although there are reports of serotonin syndrome developing after concomitant use of linezolid and the selective serotonin reuptake inhibitor paroxitene, this report concerns a patient receiving citalopram who developed thrombocytopenia, serotonin syndrome, and lactic acidosis and died following long-term linezolid therap

    Perioperative Antibiotic Prophylaxis of Wound and Foreign Body Infections: Microbial Factors Affecting Efficacy

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    Numerous microbial factors are responsible for perioperative infections and influence the efficacy of antibiotic prophylaxis. These factors include the staphylococcal carrier state, bacterial adherence to a number of host proteins, the production of glycocalyx by sessile bacteria, and shifts in antibiotic resistance. A full understanding of the mechanisms involved will lead to further reductions in the number of postoperative infections. Unfortunately, the microbial factors affecting prophylaxis cannot be evaluated separately under clinical conditions; they are easier to study under circumstances whose bacteriologic features are well defined and in which the presence of foreign materials (e.g., sutures) greatly potentiates pathogenic mechanisms. Such circumstances exist, for example, in infections developing after "clean” surgery and in experimental models. Since even clean wounds are found to be contaminated when sampled carefully, the control of infection is more a quantitative than a qualitative problem. The critical period for the development of infection is short: an antibiotic course not exceeding 24 hours seems effective in preventing infectio

    Preheating and Affleck-Dine leptogenesis after thermal inflation

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    Previously, we proposed a model of low energy Affleck-Dine leptogenesis in the context of thermal inflation. The lepton asymmetry is generated at the end of thermal inflation, which occurs at a relatively low energy scale with the Hubble parameter somewhere in the range 1 \keV \lesssim H \lesssim 1 \MeV. Thus Hubble damping will be ineffective in bringing the Affleck-Dine field into the lepton conserving region near the origin, leaving the possibility that the lepton number could be washed out. Previously, we suggested that preheating could damp the amplitude of the Affleck-Dine field allowing conservation of the lepton number. In this paper, we demonstrate numerically that preheating does efficiently damp the amplitude of the Affleck-Dine field and that the lepton number is conserved as the result. In addition to demonstrating a crucial aspect of our model, it also opens the more general possibility of low energy Affleck-Dine baryogenesis.Comment: 38 pages, 17 figure

    Successful Treatment of PulmonaryInvasive Aspergillosis with Voriconazole in Patients who FailedConventional Therapy

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    Abstract.: Background: The incidence of fungal infections, including those due to Aspergillosis species has continued to increase in recent years. Invasive aspergillosis remains an important cause of morbidity and mortality, despite therapeutics interventions. Patients and Methods: We reported five cases of invasive pulmonary aspergillosis treated with voriconazole failing to respond to conventional treatments. Results: The clinical and radiological resolution of pulmonary aspergillosis reported in these cases following therapy with voriconazole is remarkable, considering the infections had proved refractory to standard antifungal therapies. Long-term therapy (in two cases ≥ 1 year, in one case 6 months) was very well tolerated by patients who were unable to tolerate other antifungal agents. Conclusion: Therapy with voriconazole offers a new therapeutic option for otherwise difficult-to-treat infections and the potential to significantly improve the management of Aspergillosis infection

    Nocardiosis: Updated Clinical Review and Experience at a Tertiary Center

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    Abstract : Nocardiosis is a rare opportunistic disease that affects mainly patients with deficient cell-mediated immunity, such as those with acquired immunodeficiency syndrome (AIDS) or transplant recipients. Pulmonary disease is the most common presentation in immunosuppressed patients and approximately one-third have a disseminated disease. Primary cutaneous nocardiosis is more frequently observed in immunocompetent patients with direct inoculation of the organism through professional exposure. The diagnosis can be challenging, as signs and symptoms are not specific and a high index of clinical of suspicion is necessary. Although gram stain, modified acid-fast stain, and cultures remain as the standard diagnostic tools, novel molecular techniques have changed the taxonomy of these organisms and, in some instances, have facilitated their identification. The disease has a marked tendency to recur and a high morbidity and mortality rate in immunosuppressed patients. Treatment is usually prolonged and an associated antibiotic treatment is preferred for severe disease. Although sulfonamides in combination with other antibiotics are still the treatment of choice, other associations such as imipenem plus amikacin are preferred in some centers. Linezolid is a useful alternative therapeutic agent due to its oral availability and activity against most of the isolates studied. Twenty-eight cases of nocardiosis were diagnosed at our center between January 1989 and April 2009. We report the epidemiologic characteristics of Nocardia spp. observed in our institution and discuss the risk factors, clinical features, diagnosis, and management of the diseas

    Whitehead's varnish nasal pack

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    Whitehead's varnish is a little known but excellent nasal packing agent. We review available literature on the historical aspects and clinical use of Whitehead's varnish. Our personal experience with Whitehead's varnish is described, and we strongly recommend its use

    Comparative in-vitro activity of new quinolones against clinical isolates and resistant mutants

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    The in-vitro activity of five new fluoroquinolones, WIN 57273, sparfloxacin, flerox-acin, temafloxacin and tiprofloxacin was determined against 543 recent clinical isolates and eight quinolone resistant strains derived by mutation and their five parent strains. WIN 57273 was the most active compound against Gram-positive bacteria, sparfloxacin had a broad spectrum which was similar to that of cipro-floxacin. Ciprofloxacin showed the greatest activity against Gram-negative bacteria. Temafloxacin showing some activity against Gram-positive organisms and Acinetobacter spp. Fleroxacin was the least active compound studied. Compared to wild type parent strains, the mutated strains produced the following results. In Enterobacter cloacae OmpF deficiency increased the MICs of all quinolones by 8-32-fold. In Pseudomonas aeruginosa OmpF deficiency had a limited effect, Omp D2 deficiency combined with an increased lipopolysaccharide content produced greater resistance, i.e. 4-16-fold; mutations in gyrase were associated with variously increased MICs, depending on the strain and compound teste
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