497 research outputs found

    A hard metallic material: Osmium Diboride

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    We calculate the structural and electronic properties of OsB2 using density functional theory with or without taking into account spin-orbit (SO) interaction. Our results show that the bulk modulus with and without SO interaction are 364 and 365 Gpa respectively, both are in good agreement with experiment (365-395 Gpa). The evidence of covalent bonding of Os-B, which plays an important role to form a hard material, is indicated both in charge density, atoms in molecules analysis, and density of states analysis. The good metallicity and hardness of OsB2 might suggest its potential application as hard conductors.Comment: Figures improve

    Ferromagnetism in the RhGd and PtGd systems

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    Rhodium and platinum have been studied with up to 33% additions of gadolinium. The magnetic properties of the constituents in the layers of a eutectic structure are different from the bulk properties of the constituents. The compound GdPt5 orders ferromagnetically at 13.9 K

    Trends in clinical and oncological outcomes of robot-assisted radical prostatectomy before and after the 2012 US Preventive Services Task Force recommendation against PSA screening: a decade of experience

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    Objective: To assess the influence of the 2012 US Preventive Services Task Force (USPSTF) recommendation against prostate-specific antigen (PSA)-based screening on oncological and functional outcomes following robot-assisted laparoscopic prostatectomy (RALP). Materials and Methods: We retrospectively analysed patients who underwent RALP between 2008 and 2018 with a minimum of 12-month follow-up from a prospectively collected institutional review board-approved database. The impact of the USPSTF recommendation against PSA screening on our surgical outcomes was assessed using a logistic regression model using two groups comprising patients treated before/after the USPSTF statement and indicating time trends for each successive year. Results: The mean preoperative PSA increased from 6.0 to 7.4 ng/mL after the USPSTF recommendation. We detected statistically significant time-trend changes after 2012, including an increase in the positive slope of Gleason ≥3 + 4 or ≥pT3 disease. We detected a fall in bilateral full nerve-sparing and an increase in partial nerve-sparing. The total positive surgical margin (PSM) rate increased after the USPSTF recommendation; however, PSM rates pertinent to each pathological stage did not change significantly after 2012. There was a significant negative trend change in the postoperative 12-month continence and potency rates, indicating a breakpoint in functional outcomes after 2012. We detected a 1.7-fold increase in 12-month biochemical recurrence (BCR) rates. The 12-month BCR, potency and continence rates were maintained in young (<55 years) patients with a Sexual Health Inventory for Men score >22 and low-volume disease. Conclusion: Since the USPSTF’s recommendation in 2012, we have seen a significant increase in the incidence of high-risk disease that has forced us to modify our approach to the procedure and the grade of nerve-sparing used, leading to a wider resection, in order to reduce PSMs. This has led to a decrease in postoperative functional recovery. Patients with favourable characteristics had good outcomes before and after the USPSTF’s recommendation, implying that the quality of surgery did not change over time

    COVID-19 model-based practice changes in managing a large prostate cancer practice: following the trends during a month-long ordeal

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    Coronavirus (COVID-19) has been a life-changing experience for both individuals and institutions. We describe changes in our practice based on real-time assessment of various national and international trends of COVID-19 and its effectiveness in the management of our resources. Initial risk assessment and peak resource requirement using the COVID-19 Hospital Impact Model for Epidemics (CHIME) and McKinsey models. Strengths, weaknesses, opportunities, and threats (SWOT) analysis of our practice\u2019s approach during the pandemic. Based on CHIME the community followed 60% social distancing, the number of expected new patients hospitalized at maximum surge would be 401, with 100 patients requiring ventilator support. In contrast, when the community followed 15% social distancing, the maximum surge of hospitalized new patients would be 1823 and 455 patients would require a ventilator. on April 15, the expected May requirement of ICU beds at peak would be 68, with 61 patients needing ventilators. The estimated surge numbers improved throughout April, and on April 22 the expected ICU bed peak in May would be 11.7, and those requiring ventilator would be 10.5. Simultaneously, within a month, our surgical waitlist grew from 585 to over 723 patients. Our SWOT analysis revealed our internal strengths and inherent weakness, relevant to the pandemic. A graded and a guarded response to this type of situation is crucial in managing patients in a large practice

    Nature of the 5f states in actinide metals

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    Actinide elements produce a plethora of interesting physical behaviors due to the 5f states. This review compiles and analyzes progress in understanding of the electronic and magnetic structure of the 5f states in actinide metals. Particular interest is given to electron energy-loss spectroscopy and many-electron atomic spectral calculations, since there is now an appreciable library of core d -> valence f transitions for Th, U, Np, Pu, Am, and Cm. These results are interwoven and discussed against published experimental data, such as x-ray photoemission and absorption spectroscopy, transport measurements, and electron, x-ray, and neutron diffraction, as well as theoretical results, such as density-functional theory and dynamical mean-field theory.Comment: 136 pages in Word format, 29 Figures; Accepted to Reviews of Modern Physic

    Pressure-induced changes in the electronic structure of americium metal

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    We have conducted electronic-structure calculations for Am metal under pressure to investigate the behavior of the 5f-electron states. Density-functional theory (DFT) does not reproduce the experimental photoemission spectra for the ground-state phase where the 5f electrons are localized, but the theory is expected to be correct when 5f delocalization occurs under pressure. The DFT prediction is that peak structures of the 5f valence band will merge closer to the Fermi level during compression indicating presence of itinerant 5f electrons. Existence of such 5f bands is argued to be a prerequisite for the phase transitions, particularly to the primitive orthorhombic AmIV phase, but does not agree with modern dynamical-mean-field theory (DMFT) results. Our DFT model further suggests insignificant changes of the 5f valence under pressure in agreement with recent resonant x-ray emission spectroscopy, but in contradiction to the DMFT predictions. The influence of pressure on the 5f valency in the actinides is discussed and is shown to depend in a non-trivial fashion on 5f band position and occupation relative to the spd valence bands

    Feasibility of Patient Reporting of Symptomatic Adverse Events via the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events (PROCTCAE) in a Chemoradiotherapy Cooperative Group Multicenter Clinical Trial

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    Purpose—To assess the feasibility of measuring symptomatic adverse events (AEs) in a multicenter clinical trial using the National Cancer Institute’s Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE). Methods and Materials—Patients enrolled in Trial XXXX (XXXX) were asked to self-report 53 PRO-CTCAE items representing 30 symptomatic AEs at 6 time points (baseline; weekly x4 during treatment; 12-weeks post-treatment). Reporting was conducted via wireless tablet computers in clinic waiting areas. Compliance was defined as the proportion of visits when an expected PRO-CTCAE assessment was completed. Results—Among 226 study sites participating in Trial XXXX, 100% completed 35-minute PROCTCAE training for clinical research associates (CRAs); 80 sites enrolled patients of which 34 (43%) required tablet computers to be provided. All 152 patients in Trial XXXX agreed to selfreport using the PRO-CTCAE (median age 66; 47% female; 84% white). Median time for CRAs to learn the system was 60 minutes (range 30–240), and median time for CRAs to teach a patient to self-report was 10 minutes (range 2–60). Compliance was high, particularly during active treatment when patients self-reported at 86% of expected time points, although compliance was lower post-treatment (72%). Common reasons for non-compliance were institutional errors such as forgetting to provide computers to participants; patients missing clinic visits; internet connectivity; and patients feeling “too sick”. Conclusions—Most patients enrolled in a multicenter chemoradiotherapy trial were willing and able to self-report symptomatic adverse events at visits using tablet computers. Minimal effort was required by local site staff to support this system. The observed causes of missing data may be obviated by allowing patients to self-report electronically between-visits, and by employing central compliance monitoring. These approaches are being incorporated into ongoing studies

    Measuring Five Dimensions of Religiosity Across Adolescence

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    This paper theorizes and tests a latent variable model of adolescent religiosity in which five dimensions of religiosity are interrelated: religious beliefs, religious exclusivity, external religiosity, private practice, and religious salience. Research often theorizes overlapping and independent influences of single items or dimensions of religiosity on outcomes such as adolescent sexual behavior, but rarely operationalizes the dimensions in a measurement model accounting for their associations with each other and across time. We use longitudinal structural equation modeling (SEM) with latent variables to analyze data from two waves of the National Study of Youth and Religion. We test our hypothesized measurement model as compared to four alternate measurement models and find that our proposed model maintains superior fit. We then discuss the associations between the five dimensions of religiosity we measure and how these change over time. Our findings suggest how future research might better operationalize multiple dimensions of religiosity in studies of the influence of religion in adolescence

    Escherichia coli MazF Leads to the Simultaneous Selective Synthesis of Both “Death Proteins” and “Survival Proteins”

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    The Escherichia coli mazEF module is one of the most thoroughly studied toxin–antitoxin systems. mazF encodes a stable toxin, MazF, and mazE encodes a labile antitoxin, MazE, which prevents the lethal effect of MazF. MazF is an endoribonuclease that leads to the inhibition of protein synthesis by cleaving mRNAs at ACA sequences. Here, using 2D-gels, we show that in E. coli, although MazF induction leads to the inhibition of the synthesis of most proteins, the synthesis of an exclusive group of proteins, mostly smaller than about 20 kDa, is still permitted. We identified some of those small proteins by mass spectrometry. By deleting the genes encoding those proteins from the E. coli chromosome, we showed that they were required for the death of most of the cellular population. Under the same experimental conditions, which induce mazEF-mediated cell death, other such proteins were found to be required for the survival of a small sub-population of cells. Thus, MazF appears to be a regulator that induces downstream pathways leading to death of most of the population and the continued survival of a small sub-population, which will likely become the nucleus of a new population when growth conditions become less stressful

    On the importance of long-term functional assessment after stroke to improve translation from bench to bedside

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    Despite extensive research efforts in the field of cerebral ischemia, numerous disappointments came from the translational step. Even if experimental studies showed a large number of promising drugs, most of them failed to be efficient in clinical trials. Based on these reports, factors that play a significant role in causing outcome differences between animal experiments and clinical trials have been identified; and latest works in the field have tried to discard them in order to improve the scope of the results. Nevertheless, efforts must be maintained, especially for long-term functional evaluations. As observed in clinical practice, animals display a large degree of spontaneous recovery after stroke. The neurological impairment, assessed by basic items, typically disappears during the firsts week following stroke in rodents. On the contrary, more demanding sensorimotor and cognitive tasks underline other deficits, which are usually long-lasting. Unfortunately, studies addressing such behavioral impairments are less abundant. Because the characterization of long-term functional recovery is critical for evaluating the efficacy of potential therapeutic agents in experimental strokes, behavioral tests that proved sensitive enough to detect long-term deficits are reported here. And since the ultimate goal of any stroke therapy is the restoration of normal function, an objective appraisal of the behavioral deficits should be done
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