9,736 research outputs found

    Nonproductive Events in Ring-Closing Metathesis Using Ruthenium Catalysts

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    The relative TONs of productive and nonproductive metathesis reactions of diethyl diallylmalonate are compared for eight different ruthenium-based catalysts. Nonproductive cross metathesis is proposed to involve a chain-carrying ruthenium methylidene. A second more-challenging substrate (dimethyl allylmethylallylmalonate) that forms a trisubstituted olefin product is used to further delineate the effect of catalyst structure on the relative efficiencies of these processes. A steric model is proposed to explain the observed trends

    New tests of the pp-wave correspondence.

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    The pp-wave/SYM correspondence is an equivalence relation, H string = Δ-J , between the hamiltonian H string of string field theory in the pp-wave background and the dilatation operator Δ in = 4 Super Yang-Mills in the double scaling limit. We calculate matrix elements of these operators in string field theory and in gauge theory. In the string theory Hilbert space we use the natural string basis, and in the gauge theory we use the basis which is isomorphic to it. States in this basis are specific linear combinations of the original BMN operators, and were constructed previously for the case of two scalar impurities. We extend this construction to incorporate BMN operators with vector and mixed impurities. This enables us to verify from the gauge theory perspective two key properties of the three-string interaction vertex of Spradlin and Volovich: (1) the vanishing of the three-string amplitude for string states with one vector and one scalar impurity; and (2) the relative minus sign in the string amplitude involving states with two vector impurities compared to that with two scalar impurities. This implies a spontaneous breaking of the 2 symmetry of the string field theory in the pp-wave background. Furthermore, we calculate the gauge theory matrix elements of Δ-J for states with an arbitrary number of scalar impurities. In all cases we find perfect agreement with the corresponding string amplitudes derived from the three-string vertex

    The Glasgow outcome at discharge scale: an inpatient assessment of disability after brain injury

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    This study assesses the validity and reliability of the Glasgow Outcome at Discharge Scale (GODS), which is a tool that is designed to assess disability after brain injury in an inpatient setting. It is derived from the Glasgow Outcome Scale-Extended (GOS-E), which assesses disability in the community after brain injury. Inter-rater reliability on the GODS is high (quadratic-weighted kappa 0.982; 95% confidence interval [CI] 0.968, 0.996) as is concurrent validity with the Disability Rating Scale (DRS) (Spearman correlation −0.728; 95% CI −0.819, −0.601). The GODS is significantly associated with physical and fatigue subscales of the short form (SF)-36 in hospital. In terms of predictive validity the GODS is highly associated with the GOS-E after discharge (Spearman correlation 0.512; 95% CI 0.281, 0.687), with the DRS, and with physical, fatigue, and social subscales of the SF-36. The GODS is recommended as an assessment tool for disability after brain injury pre-discharge and can be used in conjunction with the GOS-E to monitor disability between hospital and the community

    The Attitudes and Beliefs About Manual Therapy Held By Patients Experiencing Low Back Pain: A Scoping Review

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    Background Manual therapy (MT) is commonly used to manage low back pain (LBP) and involves a complex interaction between the practitioner and patient. Attitudes and beliefs about MT may play a role in the outcomes seen in patients experiencing LBP. However, knowledge of patients’ attitudes and beliefs regarding MT is currently limited. Objective To map the existing published literature on the attitudes and beliefs about MT in patients experiencing LBP. Design Scoping Review. Method A systematic search was conducted across the PubMed, CINAHL, PsycINFO and Scopus databases. Study selection involved screening 1) title and abstracts and 2) full text articles. Data was analyzed to provide a descriptive summary of the studies and to develop themes of patients’ attitudes and beliefs about MT. Results A total of 767 records were identified from the initial search strategy. Following study selection, 14 articles were included for data analysis. Five themes related to patients’ attitudes and beliefs about MT were developed from the existing literature. Attitudes and beliefs about MT are explored and measured inconsistently with only one validated tool available. Conclusion MT is believed to be a preferential and effective treatment with accepted levels of post-treatment soreness. This review indicated that patients believe that MT has a biomedical mechanism of action and is suitable for biomedical causes of LBP. Several gaps in the literature are present that require further investigation

    School Site Visits: What can we learn from choice schools in Milwaukee?

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    The School Site Visits study is part of the fifth series of annual reports produced by the School Choice Demonstration Project (SCDP). It describes some of the major challenges experienced and common practices demonstrated by thirteen (13) K-12 schools participating in the Milwaukee Parental Choice Program (MPCP). During the 2010-11 school year, there were 107 religious and secular schools participating in the MPCP. This report is based on visits to six of the high schools and seven K-8 schools that collectively reflect the wide range of characteristics associated with participating schools. This includes whether schools scored above or below average on the 2010-11 Wisconsin Knowledge and Concepts Examinations in math and reading. Teams of researchers from the SCDP conducted one-day visits to each school during the spring and fall of 2011. Using a variety of interview, survey and observation instruments, the research teams gathered information about school practices in six general areas: (1) school culture, (2) student academic success, (3) effective leadership, (4) teacher quality, (5) religious integration and accommodation, and (6) school facilities. We use the data collected during the visits to describe the most common challenges the schools face and the common practices and strategies they use to overcome these challenges. Overall, a number of general lessons were learned

    A molecular biology and phase II trial of lapatinib in children with refractory CNS malignancies: a pediatric brain tumor consortium study.

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    High expression of ERBB2 has been reported in medulloblastoma and ependymoma; EGFR is amplified and over-expressed in brainstem glioma suggesting these proteins as potential therapeutic targets. We conducted a molecular biology (MB) and phase II study to estimate inhibition of tumor ERBB signaling and sustained responses by lapatinib in children with recurrent CNS malignancies. In the MB study, patients with recurrent medulloblastoma, ependymoma, and high-grade glioma (HGG) undergoing resection were stratified and randomized to pre-resection treatment with lapatinib 900 mg/m(2) dose bid for 7-14 days or no treatment. Western blot analysis of ERBB expression and pathway activity in fresh tumor obtained at surgery estimated ERBB receptor signaling inhibition in vivo. Drug concentration was simultaneously assessed in tumor and plasma. In the phase II study, patients, stratified by histology, received lapatinib continuously, to assess sustained response. Eight patients, on the MB trial (four medulloblastomas, four ependymomas), received a median of two courses (range 1-6+). No intratumoral target inhibition by lapatinib was noted in any patient. Tumor-to-plasma ratios of lapatinib were 10-20 %. In the 34 patients (14 MB, 10 HGG, 10 ependymoma) in the phase II study, lapatinib was well-tolerated at 900 mg/m(2) dose bid. The median number of courses in the phase II trial was two (range 1-12). Seven patients (three medulloblastoma, four ependymoma) remained on therapy for at least four courses range (4-26). Lapatinib was well-tolerated in children with recurrent or CNS malignancies, but did not inhibit target in tumor and had little single agent activity.Fil: Fouladi, Maryam. St. Jude Children’s Research Hospital; Estados UnidosFil: Stewart, Clinton F.. St. Jude Children’s Research Hospital; Estados UnidosFil: Blaney, Susan M.. Baylor College of Medicine. Texas Children’s Cancer Center; Estados UnidosFil: Onar Thomas, Arzu. St. Jude Children’s Research Hospital; Estados UnidosFil: Schaiquevich, Paula Susana. St. Jude Children’s Research Hospital; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Packer, Roger J.. Children’s National Medical Center; Estados UnidosFil: Goldman, Stewart. Anne and Robert H. Lurie Children’s Hospital of Chicago; Estados UnidosFil: Geyer, J. Rusell. Children’s Hospital and Regional Medical Center; Estados UnidosFil: Gajjar, Amar. St. Jude Children’s Research Hospital; Estados UnidosFil: Kun, Larry E.. St. Jude Children’s Research Hospital; Estados UnidosFil: Boyett, James M.. St. Jude Children’s Research Hospital; Estados UnidosFil: Gilbertson, Richard J.. St. Jude Children’s Research Hospital; Estados Unido
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