144 research outputs found

    Lieb-Thirring inequalities for geometrically induced bound states

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    We prove new inequalities of the Lieb-Thirring type on the eigenvalues of Schr\"odinger operators in wave guides with local perturbations. The estimates are optimal in the weak-coupling case. To illustrate their applications, we consider, in particular, a straight strip and a straight circular tube with either mixed boundary conditions or boundary deformations.Comment: LaTeX2e, 14 page

    Hormonal regulation of plasminogen activator in rat hepatoma cells

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    Plasminogen activators are membrane-associated, arginine-specific serine proteases which convert the inactive plasma zymogen plasminogen to plasmin, an active, broad-spectrum serine protease. Plasmin, the major fibrinolytic enzyme in blood, also participates in a number of physiologic functions involving protein processing and tissue remodelling, and may play an important role in tumor invasion and metastasis. In HTC rat hepatoma cells in. tissue culture, glucocorticoids rapidly decrease plasminogen activator (PA) activity. We have shown that this decrease is mediated by induction of a soluble inhibitor of PA activity rather than modulation of the amount of PA. The hormonally-induced inhibitor is a cellular product which specifically inhibits PA but not plasmin. We have isolated variant lines of HTC cells which are selectively resistant to the glucocorticoid inhibition of PA but retain other glucocorticoid responses. These variants lack the hormonally-induced inhibitor; PA from these variants is fully sensitive to inhibition by inhibitor from steroid-treated wild-type cells. Cyclic nucleotides dramatically stimulate PA activity in HTC cells in a time- and concentration-dependent manner. Paradoxically, glucocorticoids further enhance this stimulation. Thus glucocorticoids exert two separate and opposite effects on PA activity. The availability of glucocorticoid-resistant variant cell lines, together with the unique regulatory interactions of steroids and cyclic nucleotides, make HTC cells a useful experimental system in which to study the multihormonal regulation of plasminogen activator.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45346/1/11010_2004_Article_BF00225243.pd

    Towards a unified theory of Sobolev inequalities

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    We discuss our work on pointwise inequalities for the gradient which are connected with the isoperimetric profile associated to a given geometry. We show how they can be used to unify certain aspects of the theory of Sobolev inequalities. In particular, we discuss our recent papers on fractional order inequalities, Coulhon type inequalities, transference and dimensionless inequalities and our forthcoming work on sharp higher order Sobolev inequalities that can be obtained by iteration.Comment: 39 pages, made some changes to section 1

    Don't lose sight of the importance of the individual in effective falls prevention interventions

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    Falls remain a major public health problem, despite strong growth in the research evidence of effective single and multifactorial interventions, particularly in the community setting. A number of aspects of falls prevention require individual tailoring, despite limitations being reported regarding some of these, including questions being raised regarding the role of falls risk screening and falls risk assessment. Being able to personalise an individual's specific risk and risk factors, increase their understanding of what interventions are likely to be effective, and exploring options of choice and preference, can all impact upon whether or not an individual undertakes and sustains participation in one or more recommendations, which will ultimately influence outcomes. On all of these fronts, the individual patient receiving appropriate and targeted interventions that are meaningful, feasible and that they are motivated to implement, remains central to effective translation of falls prevention research evidence into practice

    A project for future life—Swedish women's thoughts on childbearing lacking experience of giving birth and parenthood

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    A lifeworld hermeneutic approach was used in order to understand Swedish women's thoughts on childbearing. Nine women were interviewed, and they ranged in age from 22 to 28 years and represented diverse socioeconomic, educational, sexual, and fertility backgrounds. All women were similar in that they lacked experience of giving birth and parenthood. The analysis showed that childbearing includes dimensions of both immanence and transcendence. Immanence, as childbearing is seen as stagnant to women's freedom in present life. Transcendence, as childbearing is thought of as a project for future life, a part of female identity, and a conscious standpoint for which the woman wants to be prepared and for which she wants to create the best conditions

    HIV, STI prevalence and risk behaviours among women selling sex in Lahore, Pakistan

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    <p>Abstract</p> <p>Background</p> <p>More than 340 million cases of curable sexually transmitted infections (STIs) were estimated to have occurred worldwide in 1995. Previous studies have shown that the presence of other concomitant STIs increases the likelihood of HIV transmission. The first national study of STIs conducted in Pakistan in 2004 revealed a high burden of STIs among women selling sex. The HIV epidemic in Pakistan has thus far followed the "Asian epidemic model". Earlier studies among women selling sex have shown a low prevalence of HIV coupled with a low level of knowledge about AIDS. The aim of our study was to estimate the prevalence of HIV and STIs, and assess knowledge and risk behaviours related to HIV/STI, among women selling sex in Lahore, Pakistan.</p> <p>Methods</p> <p>A total of 730 participants were recruited through respondent-driven sampling. The participants were women selling sex in three areas (referred to as "A", "B", and "C") of Lahore. A structured questionnaire addressing demographic information, sexual life history, sexual contacts, and knowledge and practices related to HIV/STI prevention was administered by face-to-face interview. Biological samples were obtained from all participants and tested for HIV, <it>Treponema pallidum</it>, <it>Neisseria gonorrhoeae</it>, <it>Chlamydia trachomatis </it>and <it>Trichomonas vaginalis</it>. Pearson's chi-square and multivariable logistic regression analysis were performed to test associations between potential risk factors and specified diagnosed infections.</p> <p>Results</p> <p>The prevalence of HIV infection was 0.7%, <it>T pallidum </it>4.5%, <it>N gonorrhoeae </it>7.5%, <it>C trachomatis </it>7.7% and <it>T vaginalis </it>5.1%. The participants had been selling sex for a median period of seven years and had a median of three clients per day. Sixty five percent of the participants reported that they "Always use condom". The median fee per sexual contact was Rs. 250 (3 Euro). Compared to Areas A and C, women selling sex in Area B had a significantly higher risk of chlamydial infection, gonorrhoea and trichomoniasis. Among the participants, 37% had correct knowledge about HIV/AIDS transmission and its prevention.</p> <p>Conclusions</p> <p>The prevalence of HIV was <1%, and of any other STI 18.5% among participating women selling sex in Lahore, Pakistan. A reasonably high condom use, a relatively low number of sexual partners, and a relatively low prevalence of STIs might have contributed to the low HIV prevalence.</p

    Condom Negotiations among Female Sex Workers in the Philippines: Environmental Influences

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    BackgroundSocial and structural influences of condom negotiation among female sex workers (FSWs) remain understudied. This study assesses environmental and individual factors associated with condom negotiation among FSWs at high risk for acquiring HIV in a large urban setting of Metro Manila, Philippines.MethodsFemale bar/spa workers (N = 498), aged 18 and over, underwent interview-led surveys examining their sexual health practices in the context of their risk environments. Data were collected from April 2009-January 2010 from 54 venues. Multiple logistic regressions were conducted to assess socio-behavioral factors (e.g., age, education, length of time employed as an entertainer, and alcohol/drug use) and socio-structural factors (e.g., venue-level peer/manager support, condom rule/availability, and sex trafficking) associated with condom negotiation, adjusting for individuals nested within venues.ResultsOf 142 FSWs who traded sex in the previous 6 months (included in the analysis), 24% did not typically negotiate condom use with venue patrons. Factors in the physical environment--trafficked/coerced into work (AOR = 12.92, 95% CI = 3.34-49.90), economic environment--sex without a condom to make more money (AOR = 1.52, 95% CI 1.01-2.30), policy environment--sex without a condom because none was available (AOR = 2.58, 95% CI = 1.49-4.48), and individual risk--substance use (AOR = 2.36, 95% CI = 1.28-4.35) were independently associated with FSWs' lack of condom negotiation with venue patrons.ConclusionsFactors in the physical, economic, and policy environments, over individual (excepting substance use) and social level factors, were significantly associated with these FSWs' condom negotiations in the Philippines. Drawing upon Rhodes' risk environment framework, these results highlight the need for policies that support safer sex negotiations among sex workers in the context of their risk environments. Interventions should reduce barriers to condom negotiation for FSWs trafficked/coerced into their work, substance using, and impacted by economic conditions and policies that do not support condom availability

    Wettability and corrosion of [NTf2] anion-based ionic liquids on steel and PVD (TiN, CrN, ZrN) coatings

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    Thewetting and corrosion behavior of three bis(trifluoromethylsulfonyl)imide-based ionic liquids: 1-Dodecyl-3- methylimidazolium bis(trifluoromethylsulfonyl)imide [C12MIM][NTf2], tributylmethylammonium bis(trifluoromethylsulfonyl)imide [N4441][NTf2] and methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888][NTf2] are tested in this research. The surface tension was measured for temperatures of 293–353 K resulting in the expected linearly decreasing behavior with temperature increase. In addition, contact angle measurements were made on AISI 52100 steel and three coatings (TiN, CrN and ZrN) obtained by PVD technique, finding the regular behavior in hydrophobic (non-polar) systems: high contact angles led to high surface tensions. Complementary parameters like spreading parameter and polarity fraction were calculated to enhance the wetting evaluation of these ionic liquids. [N1888][NTf2]/TiN resulted as the best IL-surface combination for a good wettability, due to the higher dispersion of the charge on the large size cation in this IL and the higher values of total and polar component of the surface free energy for this coating. Finally, SEM-EDS analysis determined that [N1888][NTf2]/ZrN was the best option in order to avoid corrosion problems. The evaporation of water, present as impurity in the ionic liquids, was found the main reason because of corrosion did not occur in the tests carried out at 100 °C

    The history of falls and the association of the timed up and go test to falls and near-falls in older adults with hip osteoarthritis

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    Abstract Background Falling accounts for a significant number of hospital and long-term care admissions in older adults. Many adults with the combination of advancing age and functional decline associated with lower extremity osteoarthritis (OA), are at an even greater risk. The purpose of this study was to describe fall and near-fall history, location, circumstances and injuries from falls in a community-dwelling population of adults over aged 65 with hip OA and to determine the ability of the timed up and go test (TUG) to classify fallers and near-fallers. Method A retrospective observational study of 106 older men and women with hip pain for six months or longer, meeting a clinical criteria for the presence of hip OA at one or both hips. An interview for fall and near-fall history and administration of the TUG were administered on one occasion. Results Forty-five percent of the sample had at least one fall in the past year, seventy-seven percent reported occasional or frequent near-falls. The majority of falls occurred during ambulation and ascending or descending steps. Forty percent experienced an injury from the fall. The TUG was not associated with history of falls, but was associated with near-falls. Higher TUG scores occurred for those who were older, less mobile, and with greater number of co-morbidities. Conclusion A high percentage of older adults with hip OA experience falls and near-falls which may be attributed to gait impairments related to hip OA. The TUG could be a useful screening instrument to predict those who have frequent near-falls, and thus might be useful in predicting risk of future falls in this population.</p
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