341 research outputs found

    Wire mesh design

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    We present a computational approach for designing wire meshes, i.e., freeform surfaces composed of woven wires arranged in a regular grid. To facilitate shape exploration, we map material properties of wire meshes to the geometric model of Chebyshev nets. This abstraction is exploited to build an efficient optimization scheme. While the theory of Chebyshev nets suggests a highly constrained design space, we show that allowing controlled deviations from the underlying surface provides a rich shape space for design exploration. Our algorithm balances globally coupled material constraints with aesthetic and geometric design objectives that can be specified by the user in an interactive design session. In addition to sculptural art, wire meshes represent an innovative medium for industrial applications including composite materials and architectural façades. We demonstrate the effectiveness of our approach using a variety of digital and physical prototypes with a level of shape complexity unobtainable using previous methods

    A Comparison of Quadriceps-to-Hamstrings Ratios During Isokinetic Testing, Cutting, and Drop Landings in Male Soccer Players

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    International Journal of Exercise Science 13(4): 157-166, 2020. Collegiate soccer is not an unusual place to suffer a knee injury. The sport has many dynamic movements, such as cutting, jumping and shooting. Many professionals use quadriceps-to-hamstring (Q/H) ratios as a tool to determine when an injured player can to return to game play or use the ratio to investigate how predisposed a certain player is to sustaining a knee injury. However, many of these ratios are taken in isokinetic testing in a controlled environment and to our knowledge it is unknown if these ratios are similar to those measured during dynamic activity. Therefore, this study investigated if there was a relationship between Q/H ratios measured during isokinetic testing and drop landings and cutting. Fifteen Division 2 collegiate male soccer players (age: 19.79 ± 1.25 years; height: 176.74 ± 6.22 cm; weight: 77.24 ± 11.01 kg). Wearing Athlos© compression shorts participants performed isokinetic testing, drop landings and cutting drills while muscle activity was measured. A significant difference was found between the bilateral Q/H ratios during the drop landings (p= 0.04; h= 0.49). There were no significant bilateral differences measured during the cutting drills in either direction and isokinetic testing (p\u3e 0.05). Additionally, there was so significant relationship in Q/H ratios between isokinetic testing and the dynamic movements (p \u3e 0.05). This suggests that clinicians should use Q/H ratios during dynamic movements rather than isokinetic testing in a controlled environment to better assess player risk disposition and return-to-play criteria

    Impacto do exercício sobre o metabolismo dos lipídeos e da dislipidemia

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    The chronic practice of exercise induces a series of cellular and organismal adaptations that modify the way the human body metabolizes all macronutrients, including lipids. Endurance exercise and resistance exercise elicit different responses that result in differential effects on lipid and lipoprotein metabolism. These effects are quantitatively and qualitatively different and mediated by distinct signaling pathways. In this review, we summarize relevant evidence on the impact of exercise on lipid and lipoprotein metabolism, and finalize with some practical recommendations on exercise practice for patients with dyslipidemia in the primary care settingLa práctica crónica del ejercicio induce una serie de adaptaciones celulares y orgánicas que modifican la forma en que el cuerpo humano metaboliza todos los macronutrientes, incluidos los lípidos. El ejercicio de duración y el ejercicio de resistencia provocan diferentes respuestas que resultan en efectos diferenciales sobre el metabolismo de los lípidos y las lipoproteínas. Estos efectos son cuantitativa y cualitativamente diferentes y mediados por distintas vías de  señalización. Esta revisión, resume la evidencia pertinente sobre la repercusión del ejercicio en el metabolismo de los lípidos y las lipoproteínas, y finaliza con algunas recomendaciones sobre la práctica del ejercicio para los pacientes con dislipidemia en el ámbito de la atención primariaA prática crônica de exercício induz uma série de adaptações celulares e orgânicas que modificam a maneira pela qual o corpo humano metaboliza todos os macronutrientes, incluindo os lipídios. O exercício de duração e o exercício de resistência provocam diversas respostas que resultam em efeitos diferenciais no metabolismo de lipídios e lipoproteínas. Estes efeitos são quantitativa e qualitativamente distintos e mediados por diferentes vias de sinalização. Nesta revisão, se resume as evidências relevantes sobre o impacto do exercício no metabolismo de lipídios e das lipoproteínas e conclui, com algumas recomendações sobre a prática de exercícios para pacientes com dislipidemia no campo da atenção primári

    Identification of a Cytotoxic Form of Dimeric Interleukin-2 in Murine Tissues

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    Interleukin-2 (IL-2) is a multi-faceted cytokine, known for promoting proliferation, survival, and cell death depending on the cell type and state. For example, IL-2 facilitates cell death only in activated T cells when antigen and IL-2 are abundant. The availability of IL-2 clearly impacts this process. Our laboratory recently demonstrated that IL-2 is retained in blood vessels by heparan sulfate, and that biologically active IL-2 is released from vessel tissue by heparanase. We now demonstrate that heparanase digestion also releases a dimeric form of IL-2 that is highly cytotoxic to cells expressing the IL-2 receptor. These cells include “traditional” IL-2 receptor-bearing cells such as lymphocytes, as well as those less well known for IL-2 receptor expression, such as epithelial and smooth muscle cells. The morphologic changes and rapid cell death induced by dimeric IL-2 imply that cell death is mediated by disruption of membrane permeability and subsequent necrosis. These findings suggest that IL-2 has a direct and unexpectedly broad influence on cellular homeostatic mechanisms in both immune and non-immune systems

    Singular Cucker-Smale Dynamics

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    The existing state of the art for singular models of flocking is overviewed, starting from microscopic model of Cucker and Smale with singular communication weight, through its mesoscopic mean-filed limit, up to the corresponding macroscopic regime. For the microscopic Cucker-Smale (CS) model, the collision-avoidance phenomenon is discussed, also in the presence of bonding forces and the decentralized control. For the kinetic mean-field model, the existence of global-in-time measure-valued solutions, with a special emphasis on a weak atomic uniqueness of solutions is sketched. Ultimately, for the macroscopic singular model, the summary of the existence results for the Euler-type alignment system is provided, including existence of strong solutions on one-dimensional torus, and the extension of this result to higher dimensions upon restriction on the smallness of initial data. Additionally, the pressureless Navier-Stokes-type system corresponding to particular choice of alignment kernel is presented, and compared - analytically and numerically - to the porous medium equation

    Visualizing Sound, Hearing Diagrams: On the Creative Process of Syrmos by Iannis Xenakis

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    A salient feature of Iannis Xenakis’ compositional practices was the use of several concepts and techniques borrowed from architectural design and from scientific fields. He sometimes drew complete graphic scores preluding the transcription of his fair copy of conventional musical notation. I discuss the diagrammatical features of Xenakis’ graphic score for Syrmos: although disparate representations depend on shared image schemata and cross-modal correspondences, their respective compositional logics are dissimilar

    Replication and Explorations of High-Order Epistasis Using a Large Advanced Intercross Line Pedigree

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    Dissection of the genetic architecture of complex traits persists as a major challenge in biology; despite considerable efforts, much remains unclear including the role and importance of genetic interactions. This study provides empirical evidence for a strong and persistent contribution of both second- and third-order epistatic interactions to long-term selection response for body weight in two divergently selected chicken lines. We earlier reported a network of interacting loci with large effects on body weight in an F2 intercross between these high– and low–body weight lines. Here, most pair-wise interactions in the network are replicated in an independent eight-generation advanced intercross line (AIL). The original report showed an important contribution of capacitating epistasis to growth, meaning that the genotype at a hub in the network releases the effects of one or several peripheral loci. After fine-mapping of the loci in the AIL, we show that these interactions were persistent over time. The replication of five of six originally reported epistatic loci, as well as the capacitating epistasis, provides strong empirical evidence that the originally observed epistasis is of biological importance and is a contributor in the genetic architecture of this population. The stability of genetic interaction mechanisms over time indicates a non-transient role of epistasis on phenotypic change. Third-order epistasis was for the first time examined in this study and was shown to make an important contribution to growth, which suggests that the genetic architecture of growth is more complex than can be explained by two-locus interactions only. Our results illustrate the importance of designing studies that facilitate exploration of epistasis in populations for obtaining a comprehensive understanding of the genetics underlying a complex trait

    The long path to pregnancy: early experience with dual anonymous gamete donation in a European in vitro fertilisation referral centre

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    <p>Abstract</p> <p>Background</p> <p>This investigation describes features of patients undergoing in vitro fertilisation (IVF) and embryo transfer (ET) where both gametes were obtained from anonymous donors.</p> <p>Methods</p> <p>Gamete unsuitability or loss was confirmed in both members of seven otherwise healthy couples presenting for reproductive endocrinology consultation over a 12-month interval in Ireland. IVF was undertaken with fresh oocytes provided by anonymous donors in Ukraine; frozen sperm (anonymous donor) was obtained from a licensed tissue establishment. For recipients, saline-enhanced sonography was used to assess intrauterine contour with endometrial preparation via transdermal estrogen.</p> <p>Results</p> <p>Among commissioning couples, mean±SD female and male age was 41.9 ± 3.7 and 44.6 ± 3.5 yrs, respectively. During this period, female age for non dual anonymous gamete donation IVF patients was 37.9 ± 3 yrs (<it>p </it>< 0.001). Infertility duration was ≥3 yrs for couples enrolling in dual gamete donation, and each had ≥2 prior failed fertility treatments using native oocytes. All seven recipient couples proceeded to embryo transfer, although one patient had two transfers. Clinical pregnancy was achieved for 5/7 (71.4%) patients. Non-transferred cryopreserved embryos were available for all seven couples.</p> <p>Conclusions</p> <p>Mean age of females undergoing dual anonymous donor gamete donation with IVF is significantly higher than the background IVF patient population. Even when neither partner is able to contribute any gametes for IVF, the clinical pregnancy rate per transfer can be satisfactory if both anonymous egg and sperm donation are used concurrently. Our report emphasises the role of pre-treatment counselling in dual anonymous gamete donation, and presents a coordinated screening and treatment approach in IVF where this option may be contemplated.</p
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