217 research outputs found

    Characterization by cDNA cloning of the mRNA for seminalplasmin, the major basic protein of bull semen.

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    A cDNA library derived from poly(A)+RNA of bull seminal vesicle tissue was screened with synthetic DNA probes specific for seminalplasmin (SAP), the major basic protein of bull semen. From a number of positive clones, pBSV12, containing a 577-bp insert, was identified and sequenced. The derived amino acid sequence comprises the known amino acid sequence of SAP with an amino terminal representing a putative signal sequence; at the carboxyl terminus the sequence contains an additional lysine residue. Present experimental data do not distinguish between two potential SAP precursor molecules, each starting with a methionine residue and differing by 10 amino acid residues in the leader peptide. Comparative Northern analysis reveals a SAP-specific mRNA of 700 bp, which lacks RNA from bovine testis as well as from seminal vesicle tissue of a bull calf; hence, expression of the SAP gene appears to be under androgen and/or developmental control. Southern analysis indicates that one gene appears to specify SAP. SAP-like DNA sequences were detected in ovine and porcine genomic DNA

    Buildup and dephasing of Floquet-Bloch bands on subcycle time scales

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    Strong light fields have created spectacular opportunities to tailor novel functionalities of solids. Floquet-Bloch states can form under periodic driving of electrons and enable exotic quantum phases. On subcycle time scales, lightwaves can simultaneously drive intraband currents and interband transitions, which enable high-harmonic generation (HHG) and pave the way towards ultrafast electronics. Yet, the interplay of intra- and interband excitations as well as their relation with Floquet physics have been key open questions as dynamical aspects of Floquet states have remained elusive. Here we provide this pivotal link by pioneering the ultrafast buildup of Floquet-Bloch bands with time- and angle-resolved photoemission spectroscopy. We drive surface states on a topological insulator with mid-infrared fields - strong enough for HHG - and directly monitor the transient band structure with subcycle time resolution. Starting with strong intraband currents, we observe how Floquet sidebands emerge within a single optical cycle; intraband acceleration simultaneously proceeds in multiple sidebands until high-energy electrons scatter into bulk states and dissipation destroys the Floquet bands. Quantum nonequilibrium calculations explain the simultaneous occurrence of Floquet states with intra- and interband dynamics. Our joint experiment-theory study opens up a direct time-domain view of Floquet physics and explores the fundamental frontiers of ultrafast band-structure engineering.Comment: 45 pages, 4 figures, 10 extended data figure

    Fundamental Parameters of He-Weak and He-Strong Stars

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    We carried out low resolution spectroscopic observations in the wavelength range 3400-4700 A of 20 He-weak and 8 He-strong stars to determine their fundamental parameters by means of the Divan-Chalonge-Barbier (BCD) spectrophotometric system. For a few He-weak stars we also estimate the effective temperatures and the angular diameters by integrating absolute fluxes observed over a wide spectral range. Non-LTE model calculations are carried out to study the influence of the He/H abundance ratio on the emergent radiation of He-strong stars and on their Teff determination. We find that the effective temperatures, surface gravities and bolometric absolute magnitudes of He-weak stars estimated with the BCD system and the integrated flux method are in good agreement between each other, and they also agree with previous determinations based on several different methods. The mean discrepancy between the visual absolute magnitudes derived using the Hipparcos parallaxes and the BCD values is on average 0.3 mag for He-weak stars, while it is 0.5 mag for He-strong stars. For He-strong stars, we note that the BCD calibration, based on stars in the solar environment, leads to overestimated values of Teff. By means of model atmosphere calculations with enhanced He/H abundance ratios we show that larger He/H ratios produce smaller BD which naturally explains the Teff overestimation. We take advantage of these calculations to introduce a method to estimate the He/H abundance ratio in He-strong stars. The BD of HD 37479 suggests that the Teff of this star remains fairly constant as the star spectrum undergoes changes in the intensity of H and He absorption lines. Data for the He-strong star HD 66765 are reported for the first time.Comment: Accepted for publication in A&

    Conceptual design of mechanisms based on computational synthesis and simulation of kinematic building blocks

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    Although many ingenious mechanisms have been designed, the fundamental task of conceptualizing these devices is, to a great extent, still an art. While sophisticated computational tools for dynamic analysis of mechanisms exist, hardly any computational methods exist for generalized synthesis. To develop a computational model for synthesis, a formal foundation for mechanisms design must be laid by rationalizing the process of mechanical synthesis. Rationalization in synthesis implies that complex mechanical motions can be described in terms of primitives or building blocks. In this paper, we present a matrix methodology that forms the basis for a computable approach to design synthesis. In this methodology, the continuous design space of a mechanisms domain is discretized into functional subspaces, and each subspace is represented uniquely by a conceptual building block. The matrix scheme serves as a formal means to (a) represent and reason with the building blocks at different levels of abstraction, (b) generate alternate conceptual design configurations, and (c) facilitate rapid simulation of design concepts by connecting a series of building blocks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45878/1/163_2005_Article_BF01580146.pd

    Interpersonal psychotherapy (IPT) for late-life depression in general practice: uptake and satisfaction by patients, therapists and physicians

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    <p>Abstract</p> <p>Background</p> <p>Interpersonal Psychotherapy (IPT) is recommended in most depression treatment guidelines and proved to be a suitable treatment for elderly depressed patients. Despite the favorable results of IPT in research populations, the dissemination to general practice is surprisingly limited. Little is known about uptake and satisfaction when this therapy is introduced into real-life general practice.</p> <p>Methods</p> <p>Motivation and evaluation of patients, GPs and therapists were recorded and organizational barriers described alongside a randomized controlled trial. IPT, given by mental health workers, was compared with usual general practitioner (GP) care. Included were patients (≥55 years) who met the DSM-IV criteria for major depressive disorder.</p> <p>Results</p> <p>Patients were motivated for the psychotherapy intervention: of the 205 eligible patients, 143 (70%) entered the study, and of the 69 patients who were offered IPT, 77% complied with the treatment. IPT proved to be an attractive therapy for patients as well as for therapists from mental health organizations. General practitioners evaluated the intervention positively afterwards, mainly because of the time-limited and structured approach. Organizational barriers: no IPT therapists were available; an IPT trainer and supervisor had to be trained and training materials had to be developed and translated. Additionally, there was a lack of office space in some general practices; for therapists from private practices it was not feasible to participate because of financial reasons. IPT was superior to usual care in patients with moderate to severe depression.</p> <p>Conclusion</p> <p>As we succeeded in delivering IPT in primary care practice, and as IPT was superior to usual care, there are grounds to support the implementation of IPT for depressed elderly patients within general practice, as long as the practices have room for the therapists and financial barriers can be overcome. Consolidation may be achieved by making this intervention available through practice nurses or community psychiatric nurses who deliver IPT as part of a more comprehensive depression management program.</p

    Can the feedback of patient assessments, brief training, or their combination, improve the interpersonal skills of primary care physicians? A systematic review

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    <p>Abstract</p> <p>Background</p> <p>Improving quality of primary care is a key focus of international health policy. Current quality improvement efforts place a large focus on technical, clinical aspects of quality, but a comprehensive approach to quality improvement should also include interpersonal care. Two methods of improving the quality of interpersonal care in primary care have been proposed. One involves the feedback of patient assessments of interpersonal care to physicians, and the other involves brief training and education programmes. This study therefore reviewed the efficacy of (i) feedback of real patient assessments of interpersonal care skills, (ii) brief training focused on the improvement of interpersonal care (iii) interventions combining both (i) and (ii)</p> <p>Methods</p> <p>Systematic review of randomised controlled trials. Three electronic databases were searched (CENTRAL, Medline and Embase) and augmented by searches of the bibliographies of retrieved articles. The quality of studies was appraised and results summarised in narrative form.</p> <p>Results</p> <p>Nine studies were included (two patient based feedback studies and seven brief training studies). Of the two feedback studies, one reported a significant positive effect. Only one training study reported a significant positive effect.</p> <p>Conclusion</p> <p>There is limited evidence concerning the effects of patient based feedback. There is reasonable evidence that brief training as currently delivered is not effective, although the evidence is not definitive, due to the small number of trials and the variation in the training methods and goals. The lack of effectiveness of these methods may reflect a number of issues, such as differences in the effectiveness of the interventions in experienced practitioners and those in training, the lack of theory linking feedback to behaviour change, failure to provide sufficient training or to use a comprehensive range of behaviour change techniques. Further research into both feedback and brief training interventions is required before these interventions are routinely introduced to improve patient satisfaction with interpersonal care in primary care. The interventions to be tested in future research should consider using insights from the wider literature on communication outside primary care, might benefit from a clearer theoretical basis, and should examine the use of combined brief training and feedback.</p
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