Harmonically confined, semiflexible polymer in a channel: response to a stretching force and spatial distribution of the endpoints

We consider an inextensible, semiflexible polymer or worm-like chain which is confined in the transverse direction by a parabolic potential and subject to a longitudinal force at the ends, so that the polymer is stretched out and backfolding is negligible. Simple analytic expressions for the partition function, valid in this regime, are obtained for chains of arbitrary length with a variety of boundary conditions at the ends. The spatial distribution of the end points or radial distribution function is also analyzed.Comment: 14 pages including figure

Estimation of the Required Amount of Hydrological Exploration in Lignite Mining Areas on the Basis of Hypothetical Hydrogeological Models

Mine drainage is a necessary but very costly precaution for open-pit lignite mining in sandy aquifers. Consequently, the minimization of the number of drainage wells and their optimal operation become important tasks in designing mine drainage systems. Comprehensive groundwater flow models have to be used, both, for the design of drainage wells, and for the analysis of water management strategies in mining areas . The accuracy of computations with such models depends on the precision of the underlying hydrogeological informations. In order to get these informations detailed and costly hydrogeological explorations have to be done in the mining regions. The basic informations are obtained using exploration drilling. The cost for hydrogeological exploration are approximately a linear function of the number of exploration bore holes. Therefore the reduction of drilling gets a key role in reducing costs of exploration. This might be done by: increased use of geophysical exploration methods; complex analysis of exploration results using mathematical statistical methods; precise estimation of the required amount of hydrogeological informations. The paper describes a mathematical approach to support the complex decision making procedure of estimating the optimal amount of hydrogeological exploration with respect to a given mine drainage goal

The pre-WDVV ring of physics and its topology

We show how a simplicial complex arising from the WDVV (Witten-Dijkgraaf-Verlinde-Verlinde) equations of string theory is the Whitehouse complex. Using discrete Morse theory, we give an elementary proof that the Whitehouse complex $\Delta_n$ is homotopy equivalent to a wedge of $(n-2)!$ spheres of dimension $n-4$. We also verify the Cohen-Macaulay property. Additionally, recurrences are given for the face enumeration of the complex and the Hilbert series of the associated pre-WDVV ring.Comment: 13 pages, 4 figures, 2 table

Statics and dynamics of single DNA molecules confined in nanochannels

The successful design of nanofluidic devices for the manipulation of biopolymers requires an understanding of how the predictions of soft condensed matter physics scale with device dimensions. Here we present measurements of DNA extended in nanochannels and show that below a critical width roughly twice the persistence length there is a crossover in the polymer physics

Family ties: Maternal-offspring attachment and young adult nonmedical prescription opioid use

Background: Nonmedical prescription drug use is prevalent among young adults, yet little is known about modifiable determinants of use. We examined whether maternal-offspring attachment reported at mean age 21 was associated with nonmedical prescription opioid use at mean age 26, and investigated whether a history of depressive symptoms and substance use played a role in associations between maternal-offspring attachment and nonmedical prescription opioid use. Methods: We used data from the Growing Up Today Study, a longitudinal cohort of United States adolescents followed into young adulthood. Maternal-offspring attachment was reported by young adults and their mothers, and defined as mutual low, mutual medium or high, and dissonant. Analyses were carried out in the full sample using generalized estimating equation models, and in a sibling subsample, using conditional fixed effects models to control for stable aspects of the family environment. Results: Analyses with the full sample and the sibling subsample both showed that mutual medium/high maternal-offspring attachment at age 21 was associated with lower odds of nonmedical prescription opioid use at age 26 (RR = 0.74; 95% CI = 0.57–0.97 in full sample). The association was partly mediated by mean age 23 offspring smoking, heavy episodic drinking, and illicit drug use. Conclusions: Promoting reciprocal attachment in the maternal-offspring dyad should be investigated as a strategy to prevent nonmedical prescription opioid use by young adulthood. Even in young adulthood, programs that target both parents and offspring may have greater impact on offspring substance use than programs that target offspring alone

Immunomagnetic t-lymphocyte depletion (ITLD) of rat bone marrow using OX-19 monoclonal antibody

Graft versus host disease (GVHD) may be abrogated and host survival prolonged by in vitro depletion of T lymphocytes from bone marrow (BM) prior to allotransplantation. Using a mouse anti-rat pan T-lymphocyte monoclonal antibody (0×19) bound to monosized, magnetic, polymer beads, T lymphocytes were removed in vitro from normal bone marrow. The removal of the T lymphocytes was confirmed by flow cytometry. Injection of the T-lymphocyte-depleted bone marrow into fully allogeneic rats prevents the induction of GVHD and prolongs host survival. A highly efficient technique of T-lymphocyte depletion using rat bone marrow is described. It involves the binding of OX-19, a MoAb directed against all rat thy-mocytes and mature peripheral T lymphocytes, to monosized, magnetic polymer spheres. Magnetic separation of T lymphocytes after mixing the allogeneic bone marrow with the bead/OX-19 complex provides for a simple, rapid depletion of T lymphocytes from the bone marrow. In vitro studies using flow cytometry and the prevention of GVHD in a fully allogeneic rat bone marrow model have been used to demonstrate the effectiveness of the depletion procedure. © 1989 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

Factors Associated with Gender-Affirming Surgery and Age of Hormone Therapy Initiation Among Transgender Adults

Abstract Purpose: Gender-affirming surgeries and hormone therapy are medically necessary treatments to alleviate gender dysphoria; however, significant gaps exist in the research and clinical literature on surgery utilization and age of hormone therapy initiation among transgender adults. Methods: We conducted a retrospective review of electronic health record data from a random sample of 201 transgender patients of ages 18–64 years who presented for primary care between July 1, 2010 and June 30, 2015 (inclusive) at an urban community health center in Boston, MA. Fifty percent in our analyses were trans masculine (TM), 50% trans feminine, and 24% reported a genderqueer/nonbinary gender identity. Regression models were fit to assess demographic, gender identity-related, sexual history, and mental health correlates of gender-affirming surgery and of age of hormone therapy initiation. Results: Overall, 95% of patients were prescribed hormones by their primary care provider, and the mean age of initiation of masculinizing or feminizing hormone prescriptions was 31.8 years (SD=11.1). Younger age of initiation of hormone prescriptions was associated with being TM, being a student, identifying as straight/heterosexual, having casual sexual partners, and not having past alcohol use disorder. Approximately one-third (32%) had a documented history of gender-affirming surgery. Factors associated with increased odds of surgery were older age, higher income levels, not identifying as bisexual, and not having a current psychotherapist. Conclusion: This study extends our understanding of prevalence and factors associated with gender-affirming treatments among transgender adults seeking primary care. Findings can inform future interventions to expand delivery of clinical care for transgender patients

Experimental evidence of magnetic flux pumping in ASDEX upgrade

In high-β scenarios with on-axis co-current electron cyclotron current drive, which normally lowers q 0 below unity, the absence of sawteeth suggests the involvement of an additional current redistribution mechanism beyond neoclassical current diffusion. This is supported by imaging motional Stark effect diagnostic measurements, which indicate that q 0 remains consistently around 1. This phenomenon is observed in the presence of a 1/1 mode, indicating its potential role in the current redistribution. It is shown that the mode’s ability to modify the central current and suppress sawteeth increases with plasma pressure. These findings align with a recent theoretical model, which predicts a pressure threshold for sawtooth avoidance by a 1/1 quasi-interchange mode and where this threshold increases with the strength of inward current diffusion. Moreover, the advantages of the flux pumping scenario for future machines are highlighted.</p