558 research outputs found

    Arc termination cracks in Inconel 718 and Incoloy 903

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    The welding of the nickel base, heat resistant alloys that are used extensively for welded Shuttle engine components revealed solidification cracking characteristics at weld termination points. If not detected and removed, these crater cracks may cause costly component failure. To better understand this characteristic, welding termination techniques were studied and methods developed to eliminate crater cracks. It was determined that weld termination solidification cracking can be eliminated by controlled decrease of welding current, welding voltage, wire feed, and travel speed

    Complement deficiencies limit CD20 monoclonal antibody treatment efficacy in CLL

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    Monoclonal antibodies (MAbs) form a central part of chronic lymphocytic leukaemia (CLL) treatment. We therefore evaluated whether complement defects in CLL patients reduced the induction of complement-dependent cytotoxicity (CDC) by using anti-CD20 MAbs rituximab (RTX) and ofatumumab (OFA). Ofatumumab elicited higher CDC levels than RTX in all CLL samples examined, particularly in poor prognosis cohorts (11q− and 17p−). Serum sample analyses revealed that 38.1% of patients were deficient in one or more complement components, correlating with reduced CDC responses. Although a proportion of patients with deficient complement levels initially induced high levels of CDC, on secondary challenge CDC activity in sera was significantly reduced, compared with that in normal human serum (NHS; P<0.01; n=52). In addition, a high CLL cell number contributed to rapid complement exhaustion. Supplementing CLL serum with NHS or individual complement components, particularly C2, restored CDC on secondary challenge to NHS levels (P<0.0001; n=9). In vivo studies revealed that complement components were exhausted in CLL patient sera post RTX treatment, correlating with an inability to elicit CDC. Supplementing MAb treatment with fresh-frozen plasma may therefore maintain CDC levels in CLL patients with a complement deficiency or high white blood cell count. This study has important implications for CLL patients receiving anti-CD20 MAb therapy

    Antimicrobial-Drug Prescription in Ambulatory Care Settings, United States, 1992–2000

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    During the 1990s, as antimicrobial resistance increased among pneumococci, many organizations promoted appropriate antimicrobial use to combat resistance. We analyzed data from the National Ambulatory Medical Care Survey, an annual sample survey of visits to office-based physicians, and the National Hospital Ambulatory Medical Care Survey, an annual sample survey of visits to hospital emergency and outpatient departments, to describe trends in antimicrobial prescribing from 1992 to 2000 in the United States. Approximately 1,100–1,900 physicians reported data from 21,000–37,000 visits; 200–300 outpatient departments reported data for 28,000–35,000 visits; ~400 emergency departments reported data for 21,000–36,000 visits each year. In that period, the population- and visit-based antimicrobial prescribing rates in ambulatory care settings decreased by 23% and 25%, respectively, driven largely by a decrease in prescribing by office-based physicians. Antimicrobial prescribing rates changed as follows: amoxicillin and ampicillin, –43%; cephalosporins, –28%; erythromycin, –76%; azithromycin and clarithromycin, +388%; quinolones, +78%; and amoxicillin/clavulanate, +72%. This increasing use of azithromycin, clarithromycin, and quinolones warrants concern as macrolide- and fluoroquinolone-resistant pneumococci are increasing

    Nanoelectromechanical Resonator Arrays for Ultrafast, Gas-Phase Chromatographic Chemical Analysis

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    Miniaturized gas chromatography (GC) systems can provide fast, quantitative analysis of chemical vapors in an ultrasmall package. We describe a chemical sensor technology based on resonant nanoelectromechanical systems (NEMS) mass detectors that provides the speed, sensitivity, specificity, and size required by the microscale GC paradigm. Such NEMS sensors have demonstrated detection of subparts per billion (ppb) concentrations of a phosphonate analyte. By combining two channels of NEMS detection with an ultrafast GC front-end, chromatographic analysis of 13 chemicals was performed within a 5 s time window

    Wide Distribution of a High-Virulence Borrelia burgdorferi Clone in Europe and North America

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    We found substantial population differentiation and recent trans-Atlantic dispersal of a high-virulence B. burgdorferi clone

    AAC W1876 hard red spring wheat

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    AAC W1876 hard red spring wheat (Triticum aestivum L.) has grain yield and time to maturity within the range of the check cultivars: Katepwa, Laura, Lillian, Carberry, and CDC Kernen. AAC W1876 has an awned spike, a low lodging score indicative of strong straw, and a short plant stature typical of a semidwarf wheat. AAC W1876 expressed resistance to prevalent races of leaf rust, moderate resistance to stem rust, intermediate resistance to fusarium head blight, yellow rust, common bunt, and loose smut. Compared to the Canada Western Red Spring check cultivars, AAC W1876 had improved flour yield and lower flour ash. AAC W1876 is eligible for grades of Canada Western Red Spring

    AAC Penhold Canada Prairie Spring Red Wheat

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    AAC Penhold, an awned hard red spring wheat (Triticum aestivum L.) cultivar, yielded significantly more grain than 5700PR while maturing 2 days earlier, and 7.5 cm shorter stature. The seed size was significantly larger than 5700PR and 5701PR, with a test weight significantly heavier than both checks. AAC Penhold expressed resistance to prevalent races of leaf rust and common bunt, and moderate resistance to fusarium head blight and stem rust. AAC Penhold had higher grain and flour protein than the checks and improved Hagberg Falling Number, amylograph viscosity, and water absorption. AAC Penhold is eligible for grades of the market class, Canada Prairie Spring Red wheat

    AAC Congress Durum Wheat

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    Congress durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.) is adapted to the durum production area of the Canadian prairies. Averaged over three years, AAC Congress yielded significantly more grain than Strongfield and AC Navigator. AAC Congress had protein concentration significantly lower than Strongfield but significantly higher than Brigade. AAC Congress is eligible for grades of Canada Western Amber Durum. It has lower grain cadmium concentration and higher yellow pigment concentration than the check cultivars, except AAC Cabri

    Modelling corneal epithelial wound closure in the presence of physiological electric fields via a moving boundary formalism

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    A new framework for the modelling of corneal epithelial wound healing is presented, which can include the presence of a physiological electric field. The difficulty inherent in the inclusion of this biological phenomenon motivates our use of a moving boundary formalism. A key conclusion is that the model predicts a linear relation between the wound healing speed and the physiological electric field strengths over a physiologically large range of electric field strength. Another key point is that this linear relationship between electric field strength and wound healing speed is robust to variations in critical parameters that are difficult to estimate. The linearity is also robust to different realizations of the modelling framework presented

    Clinician Knowledge and Beliefs after Statewide Program to Promote Appropriate Antimicrobial Drug Use

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    In 1999, Wisconsin initiated an educational campaign for primary care clinicians and the public to promote judicious antimicrobial drug use. We evaluated its impact on clinician knowledge and beliefs; Minnesota served as a control state. Results of pre- (1999) and post- (2002) campaign questionnaires indicated that Wisconsin clinicians perceived a significant decline in the proportion of patients requesting antimicrobial drugs (50% in 1999 to 30% in 2002; p<0.001) and in antimicrobial drug requests from parents for children (25% in 1999 to 20% in 2002; p = 0.004). Wisconsin clinicians were less influenced by nonpredictive clinical findings (purulent nasal discharge [p = 0.044], productive cough [p = 0.010]) in terms of antimicrobial drug prescribing. In 2002, clinicians from both states were less likely to recommend antimicrobial agent treatment for the adult case scenarios of viral respiratory illness. For the comparable pediatric case scenarios, only Wisconsin clinicians improved significantly from 1999 to 2002. Although clinicians in both states improved on several survey responses, greater overall improvement occurred in Wisconsin
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