Observation of ferromagnetism above 900 K in Cr-GaN and Cr-AlN

We report the observation of ferromagnetism at over 900K in Cr-GaN and Cr-AlN thin films. The saturation magnetization moments in our best films of Cr-GaN and Cr-AlN at low temperatures are 0.42 and 0.6 u_B/Cr atom, respectively, indicating that 14% and 20%, of the Cr atoms, respectively, are magnetically active. While Cr-AlN is highly resistive, Cr-GaN exhibits thermally activated conduction that follows the exponential law expected for variable range hopping between localized states. Hall measurements on a Cr-GaN sample indicate a mobility of 0.06 cm^2/V.s, which falls in the range characteristic of hopping conduction, and a free carrier density (1.4E20/cm^3), which is similar in magnitude to the measured magnetically-active Cr concentration (4.9E19/cm^3). A large negative magnetoresistance is attributed to scattering from loose spins associated with non-ferromagnetic impurities. The results indicate that ferromagnetism in Cr-GaN and Cr-AlN can be attributed to the double exchange mechanism as a result of hopping between near-midgap substitutional Cr impurity bands.Comment: 14 pages, 4 figures, submitted to AP

Varenicline Reduces Alcohol Intake During Repeated Cycles of Alcohol Reaccess Following Deprivation in Alcohol-Preferring (P) Rats

Background Most alcoholics experience periods of voluntary alcohol abstinence or imposed alcohol deprivation followed by a return to alcohol drinking. This study examined whether varenicline (VAR) reduces alcohol intake during a return to drinking after periods of alcohol deprivation in rats selectively bred for high alcohol drinking (the alcohol preferring or “P” rats). Methods Alcohol-experienced P rats were given 24-hour access to food and water and scheduled access to alcohol (15% and 30% v/v) for 2 h/d. After 4 weeks, rats were deprived of alcohol for 2 weeks, followed by reaccess to alcohol for 2 weeks, and this pattern was repeated for a total of 3 cycles. Rats were fed either vehicle (VEH) or VAR, in doses of 0.5, 1.0, or 2.0 mg/kg BW, at 1 hour prior to onset of the daily alcohol reaccess period for the first 5 days of each of the 3 alcohol reaccess cycles. Results Low-dose VAR (0.5 mg/kg BW) reduced alcohol intake during the 5 days of drug treatment in alcohol reaccess cycles 1 and 2. Higher doses of VAR (1.0 mg/kg BW and 2.0 mg/kg BW) reduced alcohol intake during the 5 days of treatment in all 3 alcohol reaccess cycles. The decrease in alcohol intake disappeared with termination of VAR treatment in all alcohol reaccess cycles. Conclusions The results demonstrate that VAR decreases alcohol intake during multiple cycles of alcohol reaccess following alcohol deprivation in rats and suggests that it may prevent a return to heavy alcohol drinking during a lapse from alcohol abstinence in humans with alcohol use disorder

Optical Properties of MFe_4P_12 filled skutterudites

Infrared reflectance spectroscopy measurements were made on four members of the MFe_4P_12 family of filled skutterudites, with M=La, Th, Ce and U. In progressing from M=La to U the system undergoes a metal-insulator transition. It is shown that, although the filling atom induces such dramatic changes in the transport properties of the system, it has only a small effect on lattice dynamics. We discuss this property of the compounds in the context of their possible thermoelectric applications.Comment: Manuscript in ReVTeX format, 7 figures in PostScirpt forma

Evidence for a common physical description of non-Fermi-liquid behavior in f-electron systems

The non-Fermi-liquid (NFL) behavior observed in the low temperature specific heat $C(T)$ and magnetic susceptibility $\chi(T)$ of f-electron systems is analyzed within the context of a recently developed theory based on Griffiths singularities. Measurements of $C(T)$ and $\chi(T)$ in the systems $Th_{1-x}U_{x}Pd_{2}Al_{3}$, $Y_{1-x}U_{x}Pd_3$, and $UCu_{5-x}M_{x}$ (M = Pd, Pt) are found to be consistent with $C(T)/T \propto \chi(T) \propto T^{-1+\lambda}$ predicted by this model with $\lambda <1$ in the NFL regime. These results suggest that the NFL properties observed in a wide variety of f-electron systems can be described within the context of a common physical picture.Comment: 4 pages, 4 figure

Unusual behaviors in the transport properties of REFe4_{4}P12_{12} (RE: La, Ce, Pr, and Nd)

We have investigated the resistivity ($\rho$), thermoelectric power (TEP) and Hall coefficient ($R_{H}$) on high quality single crystals of REFe$_{4}$P$_{12}$. TEP in CeFe$_{4}$P$_{12}$ is extremely large ($\sim$ 0.5mV/K at 290K) with a peak of $\sim$ 0.75mV/K at around 65K. The Hall mobility also shows a peak at $\sim$ 65K, suggesting carriers with heavy masses developed at lower temperatures related with the f-hybridized band. Both Pr- and Nd- systems exhibit an apparent increase of $\rho$ with decreasing temperature far above their magnetic transition temperatures. In the same temperature ranges, TEP exhibits unusually large absolute values of -50$\mu$V/K for PrFe$_{4}$P$_{12}$ and -15$\mu$V/K for NdFe$_{4}$P$_{12}$, respectively. For PrFe$_{4}$P$_{12}$, such anomalous transport properties suggest an unusual ground state, possibly related with the Quadrupolar Kondo effect.Comment: 5 pages, 8 figure

Plasticity and memory effects in the vortex solid phase of twinned YBa2Cu3O7 single crystals

We report on marked memory effects in the vortex system of twinned YBa2Cu3O7 single crystals observed in ac susceptibility measurements. We show that the vortex system can be trapped in different metastable states with variable degree of order arising in response to different system histories. The pressure exerted by the oscillating ac field assists the vortex system in ordering, locally reducing the critical current density in the penetrated outer zone of the sample. The robustness of the ordered and disordered states together with the spatial profile of the critical current density lead to the observed memory effects

Impact of SARS-CoV-2 on training and mental well-being of surgical gynecological oncology trainees

Introduction: The SARS-CoV-2 global pandemic has caused a crisis disrupting health systems worldwide. While efforts are being made to determine the extent of the disruption, the impact on gynecological oncology trainees/training has not been explored. We conducted an international survey of the impact of SARS-CoV-2 on clinical practice, medical education, and mental well-being of surgical gynecological oncology trainees. Methods: In our cross-sectional study, a customized web-based survey was circulated to surgical gynecological oncology trainees from national/international organizations from May to November 2020. Validated questionnaires assessed mental well-being. The Wilcoxon rank-sum test and Fisher's exact test were used to analyse differences in means and proportions. Multiple linear regression was used to evaluate the effect of variables on psychological/mental well-being outcomes. Outcomes included clinical practice, medical education, anxiety and depression, distress, and mental well-being. Results: A total of 127 trainees from 34 countries responded. Of these, 52% (66/127) were from countries with national training programs (UK/USA/Netherlands/Canada/Australia) and 48% (61/127) from countries with no national training programs. Altogether, 28% (35/125) had suspected/confirmed COVID-19, 28% (35/125) experienced a fall in household income, 20% (18/90) were self-isolated from households, 45% (57/126) had to re-use personal protective equipment, and 22% (28/126) purchased their own. In total, 32.3% (41/127) of trainees (16.6% (11/66) from countries with a national training program vs 49.1% (30/61) from countries with no national training program, p=0.02) perceived they would require additional time to complete their training fellowship. The additional training time anticipated did not differ between trainees from countries with or without national training programs (p=0.11) or trainees at the beginning or end of their fellowship (p=0.12). Surgical exposure was reduced for 50% of trainees. Departmental teaching continued throughout the pandemic for 69% (87/126) of trainees, although at reduced frequency for 16.1% (14/87), and virtually for 88.5% (77/87). Trainees reporting adequate pastoral support (defined as allocation of a dedicated mentor/access to occupational health support services) had better mental well-being with lower levels of anxiety/depression (p=0.02) and distress (p<0.001). Trainees from countries with a national training program experienced higher levels of distress (p=0.01). Mean (SD) pre-pandemic mental well-being scores were significantly higher than post-pandemic scores (8.3 (1.6) vs 7 (1.8); p<0.01). Conclusion: SARS-CoV-2 has negatively impacted the surgical training, household income, and psychological/mental well-being of surgical gynecological oncology trainees. The overall clinical impact was worse for trainees in countries with no national training program than for those in countries with a national training program, although national training program trainees reported greater distress. COVID-19 sickness increased anxiety/depression. The recovery phase must focus on improving mental well-being and addressing lost training opportunities

Ovarian cancer symptoms in pre-clinical invasive epithelial ovarian cancer - An exploratory analysis nested within the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS).

OBJECTIVE: UKCTOCS provides an opportunity to explore symptoms in preclinical invasive epithelial ovarian cancer (iEOC). We report on symptoms in women with pre-clinical (screen-detected) cancers (PC) compared to clinically diagnosed (CD) cancers. METHODS: In UKCTOCS, 202638 postmenopausal women, aged 50-74 were randomly allocated (April 17, 2001-September 29, 2005) 2:1:1 to no screening or annual screening till Dec 31,2011, using a multimodal or ultrasound strategy. Follow-up was through national registries. An outcomes committee adjudicated on OC diagnosis, histotype, stage. Eligible women were those diagnosed with iEOC at primary censorship (Dec 31, 2014). Symptom details were extracted from trial clinical-assessment forms and medical records. Descriptive statistics were used to compare symptoms in PC versus CD women with early (I/II) and advanced (III/IV/unable to stage) stage high-grade-serous (HGSC) cancer. ISRCTN-22488978; ClinicalTrials.gov-NCT00058032. RESULTS: 1133 (286PC; 847CD) women developed iEOC. Median age (years) at diagnosis was earlier in PC compared to CD (66.8PC, 68.7CD, p = 0.0001) group. In the PC group, 48% (112/234; 90%, 660/730CD) reported symptoms when questioned. Half PC (50%, 13/26PC; 36%, 29/80CD; p = 0.213) women with symptomatic HGSC had >1symptom, with abdominal symptoms most common, both in early (62%, 16/26, PC; 53% 42/80, CD; p = 0.421) and advanced (57%, 49/86, PC; 74%, 431/580, CD; p = 0.001) stages. In symptomatic early-stage HGSC, compared to CD, PC women reported more gastrointestinal (change in bowel habits and dyspepsia) (35%, 9/26PC; 9%, 7/80CD; p = 0.001) and systemic (mostly lethargy/tiredness) (27%, 7/26PC; 9%, 7/80CD; p = 0.017) symptoms. CONCLUSIONS: Our findings, add to the growing evidence, that we should reconsider what constitutes alert symptoms for early tubo-ovarian cancer. We need a more nuanced complex of key symptoms which is then evaluated and refined in a prospective trial

Concise Reporting of Benign Endometrial Biopsies is an Acceptable Alternative to Descriptive Reporting

In the United Kingdom, endometrial biopsy reports traditionally consist of a morphologic description followed by a conclusion. Recently published consensus guidelines for reporting benign endometrial biopsies advocate the use of standardized terminology. In this project we aimed to assess the acceptability and benefits of this simplified "diagnosis only" format for reporting non-neoplastic endometrial biopsies. Two consultants reported consecutive endometrial biopsies using 1 of 3 possible formats: (i) diagnosis only, (ii) diagnosis plus an accompanying comment, and (iii) the traditional descriptive format. Service users were asked to provide feedback on this approach via an anonymized online survey. The reproducibility of this system was assessed on a set of 53 endometrial biopsies among consultants and senior histopathology trainees. Of 370 consecutive benign endometrial biopsies, 245 (66%) were reported as diagnosis only, 101 (27%) as diagnosis plus a brief comment, and 24 (7%) as diagnosis following a morphologic description. Of the 43 survey respondents (28 gynecologists, 11 pathologists, and 4 clinical nurse specialists), 40 (93%) preferred a diagnosis only, with 3 (7%) being against/uncertain about a diagnosis only report. Among 3 histopathology consultants and 4 senior trainees there was majority agreement on the reporting format in 53/53 (100%) and 52/53 (98%) biopsies. In summary, we found that reporting benign specimens within standardized, well-understood diagnostic categories is an acceptable alternative to traditional descriptive reporting, with the latter reserved for the minority of cases that do not fit into specific categories. This revised approach has the potential to improve reporting uniformity and reproducibility