617 research outputs found

    Micron-sized atom traps made from magneto-optical thin films

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    We have produced magnetic patterns suitable for trapping and manipulating neutral atoms on a 1μ1 \mum length scale. The required patterns are made in Co/Pt thin films on a silicon substrate, using the heat from a focussed laser beam to induce controlled domain reversal. In this way we draw lines and "paint" shaped areas of reversed magnetization with sub-micron resolution. These structures produce magnetic microtraps above the surface that are suitable for holding rubidium atoms with trap frequencies as high as ~1 MHz.Comment: 6 pages, 7 figure

    Reconstrucción de neoglande con colgajo uretral para el tratamiento quirúrgico de calcifilaxis peniana

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    ResumenIntroducciónLa arteriolopatía urémica calcificante, también conocida como calcifilaxis, es una entidad caracterizada por la presencia de áreas de necrosis isquémica junto con extensas calcificaciones de la capa media de las arteriolas de la piel; la etiopatogenia es compleja, las formas de presentación y evolución son diversas. La calcifilaxis del pene es una entidad muy rara. El dolor y la ulceración del glande es una de sus manifestaciones clínicas iniciales, el diagnóstico en estas etapas es difícil de establecer y el manejo debe ser integral. El tratamiento médico seguido del manejo quirúrgico se establecerá de acuerdo a la etapa y evolución de la enfermedad.La reconstrucción aislada del glande se recomienda tras una amputación traumática o quirúrgica por alguna enfermedad benigna o maligna. El objetivo es conseguir una apariencia estética razonable, permitir una micción fisiológica y tratar de conservar la mayor cantidad de tejido eréctil. En pacientes con calcifilaxis peniana, el manejo quirúrgico convencional es radical y consiste en falectomía parcial o total según sea el caso. El manejo conservador ha sido reportado mediante la desbridación de las lesiones ulcerosas en pene, tratamiento local y vigilancia.Caso clínicoSe presenta el caso de un paciente masculino de 59 años de edad con insuficiencia renal crónica en tratamiento con hemodiálisis, hospitalizado por cuadro de 5 días de evolución con úlcera dolorosa en glande, refractaria a manejo analgésico. Se realizó biopsia escisional de la lesión con estudio histopatológico confirmando calcifilaxis. Se plantea a paciente falectomía parcial la cual rechaza por lo que se ofrece reconstrucción en un tiempo como opción terapéutica.ConclusiónUtilizar injertos o colgajos de piel para realizar la reconstrucción del pene en pacientes con calcifilaxis no representa una opción viable. Por su gran aporte vascular, la uretra representa una buena opción de reconstrucción en pacientes con calcifilaxis en etapa inicial. La selección y evaluación de los pacientes debe ser muy cautelosa para que los resultados estéticos y funcionales sean aceptables.AbstractIntroductionCalcific uremic arteriolopathy, also known as calciphylaxis, is an entity characterized by areas of ischemic necrosis with extensive calcifications of the middle layer of the skin arterioles. Its etiopathogenesis is complex and its forms of presentation and progression are diverse. Calciphylaxis of the penis is an extremely rare entity. Pain and ulceration of the glans penis are initial clinical manifestations and diagnosis at these stages is difficult. Management should be comprehensive. Medical treatment, followed by surgical management, is established according to disease stage and progression.Isolated reconstruction of the glans penis is recommended when there is traumatic amputation or a surgical one due to benign or malignant disease. The goal is to obtain a reasonably esthetic appearance, to have physiologic micturition, and to spare the greatest amount of erectile tissue possible. Conventional surgical management in patients with penile calciphylaxis is radical and consists of partial or total phallectomy, depending on the case. Conservative management through ulcerous penile lesion debridement, local treatment, and surveillance has been reported.Case reportA 59-year-old man with chronic renal insufficiency in hemodialysis treatment was hospitalized for symptoms of 5-day progression of a painful ulcer on the glans penis that was refractory to analgesics. An excisional biopsy of the lesion was taken and the histopathologic study confirmed calciphylaxis. Partial phallectomy was suggested to the patient, but he rejected it, and so single stage reconstruction was offered as a therapeutic option.ConclusionThe use of skin grafts or flaps for penile reconstruction in patients with calciphylaxis is not a viable option. Because of its large blood supply, the urethra is a good reconstruction option in patients with initial-stage calciphylaxis. Patient selection and evaluation must be carried out with great care in order to have acceptable functional and esthetic results

    Soldagem Por Atrito Com Pino Não Consumível De Aços Inoxidáveis Duplexa

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    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Duplex stainless steels are successful in a variety of applications such as the food industry, petrochemical and plants for desalination of seawater, where high corrosion resistance and high mechanical strength are required. However, the beneficial microstructure may be change during fusion welding steps and it can compromise the performance of these materials. Friction stir welding is a solid state process avoiding typical problems concerning solidification such as solidification cracks, liquation and segregation of alloying elements. For superduplex stainless steels can avoid unbalanced proportions of ferrite and austenite, formation of secondary deleterious phases and grain growth of ferrite in the heat affected zone. Consolidated friction stir welded joints with full penetration of 6 mm thick were obtained for UNS S32101 and S32205 duplex and S32750 and S32760 superduplex stainless steels. The friction stir welds were submitted to tensile tests indicating an improvement of strength in welded joints showing increased of yield and tensile strength for all studied cases. Regarding the microstructural characterization, an outstanding gran refinement was observed in the welded joint achieving grain sizes as small as 1 μm. This refinement was associated with the combination of microstructural restoration mechanisms in the dual phase microstructure promoted by severe deformation associated with a high temperature during the welding process. © 2016, Universidade Federal de Uberlandia. All rights reserved.2115969CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoFAPESP, Fundação de Amparo à Pesquisa do Estado de São PauloConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Information-theoretic criterion for the performance of single-photon avalanche photodiodes

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    A channel-capacity metric is introduced for assessing the performance of single-photon avalanche photodiodes (SPADs) when used as detectors in laser communication systems. This metric is employed to theoretically optimize, with respect to the device structure and operating voltage, the performance of SPADs with simple InP or In/sub 0.52/Al/sub 0.48/As-InP heterojunction multiplication regions. As the multiplication-region width increases, an increase is predicted in both the peak and the full-width at half-maximum of the channel capacity curve versus the normalized excess voltage. Calculations also show the existence of an optimal In/sub 0.52/Al/sub 0.48/As-InP heterojunction multiplication region that maximizes the peak channel capacity beyond that of InP

    Detection Efficiencies and Generalized Breakdown Probabilities for Nanosecond-Gated Near Infrared Single-Photon Avalanche Photodiodes

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    A rigorous model is developed for determining single-photon quantum efficiency (SPQE) of single-photon avalanche photodiodes (SPADs) with simple or heterojunction multiplication regions. The analysis assumes nanosecond gated-mode operation of the SPADs and that band-to-band tunneling of carriers is the dominant source of dark current in the multiplication region. The model is then utilized to optimize the SPQE as a function of the applied voltage, for a given operating temperature and multiplication-region structure and material. The model can be applied to SPADs with In/sub 0.52/Al/sub 0.48/As or InP multiplication regions as well as In/sub 0.52/Al/sub 0.48/As--InP heterojunction multiplication regions for wavelengths of 1.3 and 1.55 /spl mu/m. The predictions show that the SPQE generally decreases with decreasing the multiplication-region thickness. Moreover, an InP multiplication region requires a lower breakdown electric field (and, hence, offers a higher SPQE) than that required by an In/sub 0.52/Al/sub 0.48/As layer of the same width. The model also shows that the fractional width of the In/sub 0.52/Al/sub 0.48/As layer in an In/sub 0.52/Al/sub 0.48/As--InP heterojunction multiplication region can be optimized to attain a maximum SPQE that is greater than that offered by an InP multiplication region. This effect becomes more pronounced in thin multiplication regions as a result of the increased significance of dead space

    Air pollution and decreased bone mineral density among Women's Health Initiative participants

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    Background: Osteoporosis heavily affects postmenopausal women and is influenced by environmental exposures. Determining the impact of criteria air pollutants and their mixtures on bone mineral density (BMD) in postmenopausal women is an urgent priority. Methods: We conducted a prospective observational study using data from the ethnically diverse Women's Health Initiative Study (WHI) (enrollment, September 1994–December 1998; data analysis, January 2020 to August 2022). We used log-normal, ordinary kriging to estimate daily mean concentrations of PM10, NO, NO2, and SO2 at participants' geocoded addresses (1-, 3-, and 5-year averages before BMD assessments). We measured whole-body, total hip, femoral neck, and lumbar spine BMD at enrollment and follow-up (Y1, Y3, Y6) via dual-energy X-ray absorptiometry. We estimated associations using multivariable linear and linear mixed-effects models and mixture effects using Bayesian kernel machine regression (BKMR) models. Findings: In cross-sectional and longitudinal analyses, mean PM10, NO, NO2, and SO2 averaged over 1, 3, and 5 years before the visit were negatively associated with whole-body, total hip, femoral neck, and lumbar spine BMD. For example, lumbar spine BMD decreased 0.026 (95% CI: 0.016, 0.036) g/cm2/year per a 10% increase in 3-year mean NO2 concentration. BKMR suggested that nitrogen oxides exposure was inversely associated with whole-body and lumbar spine BMD. Interpretation: In this cohort study, higher levels of air pollutants were associated with bone damage, particularly on lumbar spine, among postmenopausal women. These findings highlight nitrogen oxides exposure as a leading contributor to bone loss in postmenopausal women, expanding previous findings of air pollution-related bone damage. Funding: US National Institutes of Health

    Apple peel and flesh contain pro-neurogenic compounds

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    As mammals evolved with exposure to particular diets, naturally abundant compounds may have become part of the set of environmental co-determinants that shaped brain structure and function. Here we investigated whether bioactive factors found in apples directly affect hippocampal neurogenesis in the adult mouse. We found that quercetin, the most abundant flavanol in apple peel, was anti-proliferative at high concentrations but pro-neurogenic at low concentrations. This was confirmed in vivo, with intraperitoneally delivered quercetin promoting survival and neuronal differentiation, without affecting proliferation. Using a bioassay-guided fractionation approach we also identified additional pro-neurogenic compounds in apple flesh that were not related to flavonoids. We found that 3,5-dihydroxybenzoic acid significantly increased neural precursor cell proliferation and neurogenesis. This work shows that both flavonoids and 3,5-dihydroxybenzoic acid are pro-neurogenic, not only by activating precursor cell proliferation but also by promoting cell-cycle exit, cellular survival, and neuronal differentiation

    Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

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    We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters

    Best Practices and Joint Calling of the HumanExome BeadChip: The CHARGE Consortium

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    Genotyping arrays are a cost effective approach when typing previously-identified genetic polymorphisms in large numbers of samples. One limitation of genotyping arrays with rare variants (e.g., minor allele frequency [MAF] <0.01) is the difficulty that automated clustering algorithms have to accurately detect and assign genotype calls. Combining intensity data from large numbers of samples may increase the ability to accurately call the genotypes of rare variants. Approximately 62,000 ethnically diverse samples from eleve

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
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