238 research outputs found

    The Mechanism of Sertoli-Germ Cell Interaction a

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73914/1/j.1749-6632.1987.tb25056.x.pd

    Space Suit Concepts and Vehicle Interfaces for the Constellation Program

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    In carrying out NASA’s Vision for Space Exploration, a number of different environments will be encountered that will require the crew to wear a protective space suit. Specifically, four suited mission phases are identified as Launch, Entry & Abort profiles, Contingency 0g (orbital) Extravehicular Activity (EVA), Lunar Surface EVA and Martian Surface EVA. This study presents conceptual design solutions based on a previous architecture assessment that defined space suit operational requirements for four proposed space suit configuration options. In addition, a subset of vehicle interface requirements are defined for enabling umbilical and physical connections between the suits and the various Constellation spacecraft in which they will be used. A summary of the resultant suit and component concepts and vehicle interface definitions is presented. This work was conducted during the fall semester of 2006 as part of a graduate aerospace engineering design class at the University of Colorado

    Characterization of three Agrobacterium tumefaciens avirulent mutants with chromosomal mutations that affect induction of vir genes.

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    Three Agrobacterium tumefaciens mutants with chromosomal mutations that affect bacterial virulence were isolated by transposon mutagenesis. Two of the mutants were avirulent on all hosts tested. The third mutant, Ivr-211, was a host range mutant which was avirulent on Bryophyllum diagremontiana, Nicotiana tabacum, N. debneyi, N. glauca, and Daucus carota but was virulent on Zinnia elegans and Lycopersicon esculentum (tomato). That the mutant phenotype was due to the transposon insertion was determined by cloning the DNA containing the transposon insertion and using the cloned DNA to replace the wild-type DNA in the parent bacterial strain by marker exchange. The transposon insertions in the three mutants mapped at three widely separated locations on the bacterial chromosome. The effects of the mutations on various steps in tumor formation were examined. All three mutants showed no alteration in binding to carrot cells. However, none of the mutants showed any induction of vir genes by acetosyringone under conditions in which the parent strain showed vir gene induction. When the mutant bacteria were examined for changes in surface components, it was found that all three of the mutants showed a similar alteration in lipopolysaccharide (LPS). LPS from the mutants was larger in size and more heavily saccharide substituted than LPS from the parent strain. Two of the mutants showed no detectable alteration in outer membrane and periplasmic space proteins. The third mutant, Ivr-225, was missing a 79-kDa surface peptide. The reason(s) for the failure of vir gene induction in these mutants and its relationship, if any, to the observed alteration in LPS are unknown

    The global decline of reptiles, deja’ vu amphibians

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    Reptile species are declining on a global scale. Six significant threats to reptile populations are habitat loss and degradation, introduced invasive species, environmental pollution, disease, unsustainable use, and global climate change

    The Work Disability Prevention CIHR Strategic Training Program: Program Performance After 5 Years of Implementation

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    Introduction The Work Disability Prevention (WDP) Canadian Institutes of Health Research (CIHR) Strategic Training Program was developed in 2001 and is a unique program in the world. The main objective of this program is to help future researchers develop transdisciplinary knowledge, skills and attitudes regarding WDP. The purpose of this paper is to present a descriptive portrait of the program's performance over the past 5 years, as well as the trainees' and alumni's perspectives on the WDP CIHR Training Program. Methods Data on the program's performance were collected from documents in the program records. The trainees' opinions on the WDP training program were obtained through focus groups and telephone interviews. The data collected were compiled and divided into themes to summarize the qualitative findings pertaining to each question. Results From 2003 to 2007, five successive summer sessions have been offered, involving 44 high-caliber applicants from nine countries, 34 mentors and collaborators, 29 guest speakers and 15 stakeholders. Overall, trainees appreciated the networking, the opportunity to interact with people from different disciplines and countries, the openness, and the international perspective and uniqueness of the program. The least appreciated aspects concerned mainly the e-learning course, evaluations and information on optional courses. The coordination and logistics were judged appropriate and several topics were suggested to improve the program quality. Conclusion In general, the program implementation went well, with good participation from mentors, speakers and stakeholders; the program was appreciated by the trainees and alumni. This paper underscores the importance of the international perspective, the transdisciplinarity and the scientific networking established through the progra

    Using intervention mapping and behavior change techniques to develop a digital intervention for self-management in stroke: Development study

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    BACKGROUND: Digital therapeutics, such as interventions provided via smartphones or the internet, have been proposed as promising solutions to support self-management in persons with chronic conditions. However, the evidence supporting self-management interventions through technology in stroke is scarce, and the intervention development processes are often not well described, creating challenges in explaining why and how the intervention would work. OBJECTIVE: This study describes a specific use case of using intervention mapping (IM) and the taxonomy of behavior change techniques (BCTs) in designing a digital intervention to manage chronic symptoms and support daily life participation in people after stroke. IM is an implementation science framework used to bridge the gap between theories and practice to ensure that the intervention can be implemented in real-world settings. The taxonomy of BCTs consists of a set of active ingredients designed to change self-management behaviors. METHODS: We used the first 4 steps of the IM process to develop a technology-supported self-management intervention, interactive Self-Management Augmented by Rehabilitation Technologies (iSMART), adapted from a face-to-face stroke-focused psychoeducation program. Planning group members were involved in adapting the intervention. They also completed 3 implementation measures to assess the acceptability, appropriateness, and feasibility of iSMART. RESULTS: In step 1, we completed a needs assessment consisting of assembling a planning group to codevelop the intervention, conducting telephone surveys of people after stroke (n=125) to identify service needs, and performing a systematic review of randomized controlled trials to examine evidence of the effectiveness of digital self-management interventions to improve patient outcomes. We identified activity scheduling, symptom management, stroke prevention, access to care resources, and cognitive enhancement training as key service needs after a stroke. The review suggested that digital self-management interventions, especially those using cognitive behavioral theory, effectively reduce depression, anxiety, and fatigue and enhance self-efficacy in neurological disorders. Step 2 identified key determinants, objectives, and strategies for self-management in iSMART, including knowledge, behavioral regulation, skills, self-efficacy, motivation, negative and positive affect, and social and environmental support. In step 3, we generated the intervention components underpinned by appropriate BCTs. In step 4, we developed iSMART with the planning group members. Especially, iSMART simplified the original psychoeducation program and added 2 new components: SMS text messaging and behavioral coaching, intending to increase the uptake by people after stroke. iSMART was found to be acceptable (mean score 4.63, SD 0.38 out of 5), appropriate (mean score 4.63, SD 0.38 out of 5), and feasible (mean score 4.58, SD 0.34 out of 5). CONCLUSIONS: We describe a detailed example of using IM and the taxonomy of BCTs for designing and developing a digital intervention to support people after stroke in managing chronic symptoms and maintaining active participation in daily life

    Accounting for variability when resurrecting dormant propagules substantiates their use in eco-evolutionary studies

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    There has been a steady rise in the use of dormant propagules to study biotic responses to environmental change over time. This is particularly important for organisms that strongly mediate ecosystem processes, as changes in their traits over time can provide a unique snapshot into the structure and function of ecosystems from decades to millennia in the past. Understanding sources of bias and variation is a challenge in the field of resurrection ecology, including those that arise because often-used measurements like seed germination success are imperfect indicators of propagule viability. Using a Bayesian statistical framework, we evaluated sources of variability and tested for zero-inflation and overdispersion in data from 13 germination trials of soil-stored seeds of Schoenoplectus americanus, an ecosystem engineer in coastal salt marshes in the Chesapeake Bay. We hypothesized that these two model structures align with an ecological understanding of dormancy and revival: zero-inflation could arise due to failed germinations resulting from inviability or failed attempts to break dormancy, and overdispersion could arise by failing to measure important seed traits. A model that accounted for overdispersion, but not zero-inflation, was the best fit to our data. Tetrazolium viability tests corroborated this result: most seeds that failed to germinate did so because they were inviable, not because experimental methods failed to break their dormancy. Seed viability declined exponentially with seed age and was mediated by seed provenance and experimental conditions. Our results provide a framework for accounting for and explaining variability when estimating propagule viability from soil-stored natural archives which is a key aspect of using dormant propagules in eco-evolutionary studies

    Borrelia valaisiana resist complement-mediated killing independently of the recruitment of immune regulators and inactivation of complement components

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    Spirochetes belonging to the Borrelia (B.) burgdorferi sensu lato complex differ in their resistance to complement-mediated killing, particularly in regard to human serum. In the present study, we elucidate the serum and complement susceptibility of B. valaisiana, a genospecies with the potential to cause Lyme disease in Europe as well as in Asia. Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum. Analyzing complement activation, complement components C3, C4 and C6 were deposited on the surface of isolates VS116 and Bv9, and similarly the membrane attack complex was formed on their surface. In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3. While further investigating the protective role of bound complement regulators in mediating complement resistance, we discovered that none of the B. valaisiana isolates analyzed bound complement regulators Factor H, Factor H-like protein 1, C4b binding protein or C1 esterase inhibitor. In addition, B. valaisiana also lacked intrinsic proteolytic activity to degrade complement components C3, C3b, C4, C4b, and C5. Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum. The molecular mechanism utilized by B. valaisiana to inhibit bacteriolysis appears not to involve binding of the key host complement regulators of the alternative, classical, and lectin pathways as already known for serum-resistant Lyme disease or relapsing fever borreliae

    A smartphone-based technique to detect dynamic user preferences for tailoring behavioral interventions: Observational utility study of ecological daily needs assessment

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    BACKGROUND: Mobile health apps are promising vehicles for delivering scalable health behavior change interventions to populations that are otherwise difficult to reach and engage, such as young adults with psychiatric conditions. To improve uptake and sustain consumer engagement, mobile health interventions need to be responsive to individuals\u27 needs and preferences, which may change over time. We previously created an ecological daily needs assessment to capture microprocesses influencing user needs and preferences for mobile health treatment adaptation. OBJECTIVE: The objective of our study was to test the utility of a needs assessment anchored within a mobile app to capture individualized, contextually relevant user needs and preferences within the framework of a weight management mobile health app. METHODS: Participants with an iOS device could download the study app via the study website or links from social media. In this fully remote study, we screened, obtained informed consent from, and enrolled participants through the mobile app. The mobile health framework included daily health goal setting and self-monitoring, with up to 6 daily prompts to determine in-the-moment needs and preferences for mobile health-assisted health behavior change. RESULTS: A total of 24 participants downloaded the app and provided e-consent (22 female; 2 male), with 23 participants responding to at least one prompt over 2 weeks. The mean length of engagement was 5.6 (SD 4.7) days, with a mean of 2.8 (1.1) responses per day. We observed individually dynamic needs and preferences, illustrating daily variability within and between individuals. Qualitative feedback indicated preferences for self-adapting features, simplified self-monitoring, and the ability to personalize app-generated message timing and content. CONCLUSIONS: The technique provided an individually dynamic and contextually relevant alternative and complement to traditional needs assessment for assessing individually dynamic user needs and preferences during treatment development or adaptation. The results of this utility study suggest the importance of personalization and learning algorithms for sustaining app engagement in young adults with psychiatric conditions. Further study in broader user populations is needed

    A megbocsátás pszichológiája: kialakulása, hatásai és fejlesztése

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    A megbocsátás az interperszonális sérelmekre adott egyik lehetséges válasznak tekinthető, melynek fókuszában a sérelmet elszenvedő személy kognitív, érzelmi és viselkedéses válaszaiban bekövetkező proszociális változás áll. A megbocsátás mentális és fizikai egészségre kifejtett pozitív hatása jól dokumentált. Magas szintje alacsony szorongás- és depressziószinttel társul, illetve sikeresen csökkenti a stresszre adott fizikai választ (kortizol és kardiovaszkuláris reaktivitás). A megbocsátást - hatásai alapján - olyan emóció fókuszú megküzdési módként definiálhatjuk, mely sikeresen csökkenti az interperszonális sérelem nyomán kialakult stresszreakciót. Az utóbbi években számos intervenciós technikát dolgoztak ki, melyek a megbocsátás támogatását, illetve fejlesztését tűzték ki célként. Ezek a módszerek általában sikeresen növelik a megbocsátásra való hajlandóságot.</o:p
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