310 research outputs found

    Single crystals of metal solid solutions

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    The following definitions were sought in the research on single crystals of metal solid solutions: (1) the influence of convection and/or gravity present during crystallization on the substructure of a metal solid solution; (2) the influence of a magnetic field applied during crystallization on the substructure of a metal solid solution; and (3) requirements for a space flight experiment to verify the results. Growth conditions for the selected silver-zinc alloy system are described, along with pertinent technical and experimental details of the project

    Cohesin Removal along the Chromosome Arms during the First Meiotic Division Depends on a NEK1-PP1γ-WAPL Axis in the Mouse

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    SummaryMammalian NIMA-like kinase-1 (NEK1) is a dual-specificity kinase highly expressed in mouse germ cells during prophase I of meiosis. Loss of NEK1 induces retention of cohesin on chromosomes at meiotic prophase I. Timely deposition and removal of cohesin is essential for accurate chromosome segregation. Two processes regulate cohesin removal: a non-proteolytic mechanism involving WAPL, sororin, and PDS5B and direct cleavage by separase. Here, we demonstrate a role for NEK1 in the regulation of WAPL loading during meiotic prophase I, via an interaction between NEK1 and PDS5B. This regulation of WAPL by NEK1-PDS5B is mediated by protein phosphatase 1 gamma (PP1γ), which both interacts with and is a phosphotarget of NEK1. Taken together, our results reveal that NEK1 phosphorylates PP1γ, leading to the dephosphorylation of WAPL, which, in turn, results in its retention on chromosome cores to promote loss of cohesion at the end of prophase I in mammals

    Strong asymptotics for Jacobi polynomials with varying nonstandard parameters

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    Strong asymptotics on the whole complex plane of a sequence of monic Jacobi polynomials Pn(αn,βn)P_n^{(\alpha_n, \beta_n)} is studied, assuming that limnαnn=A,limnβnn=B, \lim_{n\to\infty} \frac{\alpha_n}{n}=A, \qquad \lim_{n\to\infty} \frac{\beta _n}{n}=B, with AA and BB satisfying A>1 A > -1, B>1 B>-1, A+B<1A+B < -1. The asymptotic analysis is based on the non-Hermitian orthogonality of these polynomials, and uses the Deift/Zhou steepest descent analysis for matrix Riemann-Hilbert problems. As a corollary, asymptotic zero behavior is derived. We show that in a generic case the zeros distribute on the set of critical trajectories Γ\Gamma of a certain quadratic differential according to the equilibrium measure on Γ\Gamma in an external field. However, when either αn\alpha_n, βn\beta_n or αn+βn\alpha_n+\beta_n are geometrically close to Z\Z, part of the zeros accumulate along a different trajectory of the same quadratic differential.Comment: 31 pages, 12 figures. Some references added. To appear in Journal D'Analyse Mathematiqu

    Functional Social Support Moderates Stress on Depression in Individuals with CID during the COVID-19 Pandemic: A Two-Wave Study.

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    Depression is a common psychological experience for those living with a chronic illness and disease (CID). Social support (SS) can influence psychological health by regulating emotional functioning. The functional domain of SS refers to supportive exchange, including the emotional and instrumental functions. Public health measures during the COVID-19 pandemic include social distancing and isolation, which have impacted functional aspects of SS. The health risks of being isolated are comparable to the risks linked to obesity, blood pressure, and cigarette smoking. PURPOSE: To investigate the moderating effect of functional SS on the stress-depression relationship on individuals with CID during the COVID-19 pandemic. METHODS: Two waves of data were collected from a US sample: Apr. ’20: N = 321; Jun. ’20: N = 238. Participants completed the Patient Health Questionnaire–9 (depression symptoms), the Medical Outcomes Study–Social Support Survey–8 (perceived social support), and the Perceived Stress Scale–10 (perceived stress). For each wave of data, social support was entered as a moderator of the stress-depression relationship via multiple regression. RESULTS: The moderation models were estimated separately by wave. In the first wave, there was a negative but nonsignificant moderating effect (b = -0.19, p = .10) of social support on the stress-depression relationship (R2 = 51). In the second wave, the moderating relationship of social support doubled in magnitude (b = -0.30, p = .03, R2 = .57). During the COVID pandemic, functional social support weakened the association between stress and depression. CONCLUSION: Given the increased risk for social isolation and negative social exchange among people with CID during the COVID-19 pandemic, practitioners in rehabilitation psychology need to be informed about the potential implications of a lack of SS for the psychological health of the CID clients they work with. Drawing from the stress-buffering model and Lazarus et al.’s stress and coping theory (Lazarus, 1966; Lazarus & Folkman, 1984), our findings indicate that increased levels of perceived support can reduce the effects of stress on depression during the pandemic by contributing to fewer negative appraisals. Interventions targeting the particular functions of emotional (e.g., opportunities for emotional expression and venting) and instrumental (e.g., material aid) support could have immediate implications for facilitating rehabilitation outcomes (e.g., quality of life, interpersonal functioning, psychiatric symptomatology) during this public health crisis

    Transitions In Spectral Statistics

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    We present long range statistical properties of a recently introduced unitary random matrix ensemble, whose short range correlations were found to describe a transition from Wigner to Poisson type as a function of a single parameter.Comment: 12 pp. late

    Coherent radiation from neutral molecules moving above a grating

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    We predict and study the quantum-electrodynamical effect of parametric self-induced excitation of a molecule moving above the dielectric or conducting medium with periodic grating. In this case the radiation reaction force modulates the molecular transition frequency which results in a parametric instability of dipole oscillations even from the level of quantum or thermal fluctuations. The present mechanism of instability of electrically neutral molecules is different from that of the well-known Smith-Purcell and transition radiation in which a moving charge and its oscillating image create an oscillating dipole. We show that parametrically excited molecular bunches can produce an easily detectable coherent radiation flux of up to a microwatt.Comment: 4 page

    Effective cardiac resynchronization therapy for an adolescent patient with dilated cardiomyopathy seven years after mitral valve replacement and septal anterior ventricular exclusion

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    Cardiac resynchronization therapy (CRT) is a new treatment for refractory heart failure. However, most heart failure patients treated with CRT are middle-aged or old patients with idiopathic or ischemic dilated cardiomyopathy. We treated a 17 year 11 month old girl with dilated cardiomyopathy after mitral valve replacement (MVR) and septal anterior ventricular exclusion (SAVE). Seven years after the SAVE procedure, she presented complaining of palpitations and general fatigue with normal activity. Her echocardiogram showed reduced left ventricular function. Despite of optimal medical therapy, her left ventricular function continued to decline and she experienced regular arrhythmias such as premature ventricular contractions. We thus elected to perform cardiac resynchronization therapy with defibrillator (CRT-D). After CRT-D, her clinical symptoms improved dramatically and left ventricular ejection fraction (LVEF) improved from 31.2% to 51.3% as assessed by echocardiogram. Serum BNP levels decreased from 448.2 to 213.6 pg/ml. On ECG, arrhythmias were remarkably reduced and QRS duration was shortened from 174 to 152 msec. In conclusion, CRT-D is an effective therapeutic option for adolescent patients with refractory heart failure after left ventricular volume reduction surgery

    IV sotalol use in pediatric and congenital heart patients: A multicenter registry study

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    Background There is limited information regarding the clinical use and effectiveness of IV sotalol in pediatric patients and patients with congenital heart disease, including those with severe myocardial dysfunction. A multicenter registry study was designed to evaluate the safety, efficacy, and dosing of IV sotalol. Methods and Results A total of 85 patients (age 1 day-36 years) received IV sotalol, of whom 45 (53%) had additional congenital cardiac diagnoses and 4 (5%) were greater than 18 years of age. In 79 patients (93%), IV sotalol was used to treat supraventricular tachycardia and 4 (5%) received it to treat ventricular arrhythmias. Severely decreased cardiac function by echocardiography was seen before IV sotalol in 7 (9%). The average dose was 1 mg/kg (range 0.5-1.8 mg/kg/dose) over a median of 60 minutes (range 30-300 minutes). Successful arrhythmia termination occurred in 31 patients (49%, 95% CI [37%-62%]) with improvement in rhythm control defined as rate reduction permitting overdrive pacing in an additional 18 patients (30%, 95% CI [19%-41%]). Eleven patients (16%) had significant QTc prolongation to \u3e465 milliseconds after the infusion, with 3 (4%) to \u3e500 milliseconds. There were 2 patients (2%) for whom the infusion was terminated early. Conclusions IV sotalol was safe and effective for termination or improvement of tachyarrhythmias in 79% of pediatric patients and patients with congenital heart disease, including those with severely depressed cardiac function. The most common dose, for both acute and maintenance dosing, was 1 mg/kg over ~60 minutes with rare serious complications

    Pilot, randomized, placebo-controlled clinical field study to evaluate the effectiveness of bupivacaine liposome injectable suspension for the provision of post-surgical analgesia in dogs undergoing stifle surgery

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    Abstract Background Local anesthetics are an important component of perioperative pain management, but the duration of action of available products is limited. We hypothesized that a single local infiltration of a novel bupivacaine liposome injectable suspension (AT-003) would provide clinically effective analgesia over a 72-h period. In a masked, randomized, placebo-controlled, multi-center pilot field study, dogs undergoing lateral retinacular suture placement for cranial cruciate insufficiency were randomly assigned to surgical site infiltration with AT-003 (5.3 mg/kg) or an equivalent volume of saline. Infiltration of the surgical site was done prior to closure. Primary outcome measure was the Glasgow Composite Measure Pain Scale (CMPS-SF) assessed prior to surgery and at 2, 4, 8, 12, 24, 30, 36, 48, 54, 60 and 72 h following surgery by trained individuals. Provision for rescue analgesia was employed. Repeated measures analysis of variance were utilized to test for possible differences between treatment groups and a success/failure analysis was also employed, based on the need for rescue analgesia. Results Forty-six dogs were enrolled and evaluated. For CMPS-SF scores there was a significant overall treatment effect (p = 0.0027) in favor of AT-003. There were significantly more successes in the AT-003 group compared to placebo over each time period (p = 0.0001 for 0–24 h, p = 0.0349 for 0–48 h, and p = 0.0240 for 0-72 h). No significant adverse events were seen. Conclusions AT-003 (bupivacaine liposome injectable suspension) provided measurable local analgesia over a 72-h period following post-stifle surgery surgical site tissue infiltration. Further work is indicated to develop this product for clinical use
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