Effect of implanted metal impurities on superconducting tungsten films

The superconducting transition temperature of more than 30 thin-film tungsten samples was measured using a dilution refrigerator. The samples were fabricated using a 99.999% pure tungsten target and a dc magnetron sputtering system. Individual films were then doped with metal impurity ions using an accurate ion implantation technique. The effect of the metal–ion doping on the superconducting transition temperature was measured for samples with superconducting transitions in the range of 40–150 mK. Magnetic dopant species including Ni, Co, and Fe resulted in suppressed values of the tungsten Tc. The suppression was linear with increasing dopant concentration, for concentrations up to tens of ppm. For higher concentrations of magnetic atoms, the data are consistent with the Abrikosov–Gor\u27kov theory [Soviet Physics JETP 12, 1243 (1961)] modified by antiferromagnetic impurity–impurity interactions. By contrast, tungsten films implanted with Mg or Cr showed little change in Tc after doping. In this article, we present data from cryogenic experiments on these films. We also present x-ray diffraction (XRD) spectra for a subset of the films. Our XRD data confirm that the observed suppression in Tc for the magnetically doped samples is not due to any structural changes (e.g., lattice distortion or damage) induced by the implantation process

Acute study of dose-dependent effects of (-)-epicatechin on vascular function in healthy male volunteers: a randomized controlled trial

BACKGROUND & AIMS There is convincing clinical evidence to suggest that flavanol-containing foods/beverages are capable of inducing improvements in human vascular function. However, whilst (-)-epicatechin has been tested for efficacy, a full dose-dependency has yet to be established, particularly at doses below 1 mg/kg BW. The current study examined the dose-dependent effects of (-)-epicatechin on human vascular function with concurrent measurement of plasma (-)-epicatechin metabolites and levels of circulating nitrite and nitrate species, NOx. METHODS An acute, double-blind, placebo-controlled, crossover intervention trial was conducted in 20 healthy males with 4 treatment arms: water-based (-)-epicatechin (0.1, 0.5 and 1.0 mg/kg BW) and a water only as control. Vascular function was assessed by flow-mediated dilatation (FMD) measured at the brachial artery, laser Doppler imaging with iontophoresis (LDI) at the subcutaneous capillaries of the forearm (response to Ach and SNP) and peripheral blood pressure (BP) at baseline, 1, 2, 4 and 6 h post-intervention. Plasma analysis of epicatechin metabolites was conducted by LC-MS and circulating plasma of nitrite and nitrate species were performed using an HPLC-based system (ENO-30). RESULTS Significant increases in % FMD were found to occur at 1 and 2 h following intake of 1 mg/kg BW, and at 2 h for the 0.5 mg/kg BW intake. There were no significant changes in LDI or BP at any time-points or intake levels. Increases in FMD over the 6 h timeframe were closely paralleled by the appearance of total plasma (-)-epicatechin metabolites. Non-significant changes in circulating NOx was observed. CONCLUSIONS Our data add further evidence that (-)-epicatechin is a causal vasoactive molecule within flavanol-containing foods/beverages. In addition, we show for the first time that intake levels as low as 0.5 mg/kg BW are capable of inducing acute improvements in vascular function (FMD) in healthy volunteers

The Complexity of Combinations of Qualitative Constraint Satisfaction Problems

The CSP of a first-order theory $T$ is the problem of deciding for a given finite set $S$ of atomic formulas whether $T \cup S$ is satisfiable. Let $T_1$ and $T_2$ be two theories with countably infinite models and disjoint signatures. Nelson and Oppen presented conditions that imply decidability (or polynomial-time decidability) of $\mathrm{CSP}(T_1 \cup T_2)$ under the assumption that $\mathrm{CSP}(T_1)$ and $\mathrm{CSP}(T_2)$ are decidable (or polynomial-time decidable). We show that for a large class of $\omega$-categorical theories $T_1, T_2$ the Nelson-Oppen conditions are not only sufficient, but also necessary for polynomial-time tractability of $\mathrm{CSP}(T_1 \cup T_2)$ (unless P=NP).Comment: Version 2: stronger main result with better presentation of the proof; multiple improvements in other proofs; new section structure; new example

Risk Factors for Cervical Precancer and Cancer in HIV-Infected, HPV-Positive Rwandan Women

Although cervical cancer is an AIDS-defining condition, infection with human immunodeficiency virus (HIV) may only modestly increase the risk of cervical cancer. There is a paucity of information regarding factors that influence the natural history of human papillomavirus (HPV) in HIV-infected women. We examined factors associated with cervical intraepithelial neoplasia grade 3 or cancer (CIN3+) in Rwandan women infected with both HIV and HPV (HIV+/HPV+).In 2005, 710 HIV+ Rwandan women ≥25 years enrolled in an observational cohort study; 476 (67%) tested HPV+. Each woman provided sociodemographic data, CD4 count, a cervical cytology specimen and cervicovaginal lavage (CVL), which was tested for >40 HPV genotypes by MY09/MY11 PCR assay. Logistic regression models calculated odds ratios (OR) and 95% confidence intervals (CI) of associations of potential risk factors for CIN3+ among HIV+/HPV+ women.Of the 476 HIV+/HPV+ women 42 (8.8%) were diagnosed with CIN3+. Factors associated with CIN3+ included ≥7 (vs. 0-2) pregnancies, malarial infection in the previous six months (vs. never), and ≥7 (vs. 0-2) lifetime sexual partners. Compared to women infected by non-HPV16 carcinogenic HPV genotypes, HPV16 infection was positively associated and non-carcinogenic HPV infection was inversely associated with CIN3+. CD4 count was significantly associated with CIN3+ only in analyses of women with non-HPV16 carcinogenic HPV (OR = 0.62 per 100 cells/mm(3), CI = 0.40-0.97).In this HIV+/HPV+ population, lower CD4 was significantly associated with CIN3+ only in women infected with carcinogenic non-HPV16. We found a trend for higher risk of CIN3+ in HIV+ women reporting recent malarial infection; this association should be investigated in a larger group of HIV+/HPV+ women

Reduced Career Longevity but Return to Baseline Performance After Arthroscopic Shoulder Labral Repair in National Hockey League Players

PURPOSE: To investigate the impact of arthroscopic shoulder labral repair without shoulder instability on career longevity, game use, and performance in National Hockey League (NHL) athletes. METHODS: A retrospective review of all NHL players who underwent arthroscopic shoulder labral repair from 2004 to 2020 was performed. A 2:1 matched control group was used for comparison. Controls were matched by age, body mass index, position, and experience prior to the index year. Demographic characteristics, game use, and performance metrics were collected for all athletes. Statistical analysis examined game use and performance both at 1-year and 3-year follow-up compared with one season before injury. RESULTS: Twenty-nine players who underwent arthroscopic shoulder labral surgery returned to play (100%) and were matched with 55 control players. The operative cohort experienced shorter careers compared with controls (4.4 ± 3.1 vs 6.0 ± 3.6 seasons, P < .05). After one season, injured players experienced significant reductions in goals per 60 (0.6 ± 0.4 vs 0.8 ± 0.5, P = .013), points per 60 (1.5 ± 0.9 vs 2.0 ± 0.9, P = .001), and shooting percentage, (8.5 ± 5.8 vs 10.5 ± 5.2, P = .02) compared with the year prior. The reduction in goals (0.6 ± 0.4 vs 0.8 ± 0.5, P = .01) and shooting % (8.5 ± 4.7 vs 10.5 ± 5.2, P = .04) persisted at 3 years. Compared with controls, the surgical group experienced significant reductions at one season postindex in percentage of goals, assists, points per 60, and shooting percentage. Only the reduction in goals per 60 persisted at 3 seasons postindex. CONCLUSIONS: Following return to play after arthroscopic shoulder labral repair, NHL players demonstrated reduced career longevity compared with healthy controls. Players exhibited significant reductions in game use and performance at one season after injury but returned closer to baseline after 3 seasons. LEVEL OF EVIDENCE: Level III; retrospective case control

Mechanical and magnetic properties of spark plasma sintered soft magnetic FeCo alloy reinforced by carbon nanotubes

Different volume fractions (0.5 vol. % to 4.5 vol. %) of CNTs were used to reinforce a binary Fe50Co soft magnetic alloy. The first method for dispersion was involved dry mixing and ball milling of the powder, while the second was included wet mixing in dimethylformamide under ultrasonic agitation, drying and then dry ball milling. The powders were consolidated using spark plasma sintering. Tensile test and SEM analyses were performed to characterize the mechanical properties and the fracture surface of the sintered materials. The best magnetic and mechanical properties were achieved using the first method. A maximum enhancement in tensile strength of around 20% was observed in the 0.5 vol. % CNT composite with improved elongation compared to the monolithic Fe50Co alloy. In addition, the magnetic properties were enhanced by adding CNTs up to 1 vol. %, and an improvement in densification was observed in composites up to 1.5 vol. % CNT with respect to monolithic Fe50Co alloy

Book Reviews

Book Reviews: Overthrow: America's Century of Regime Change From Hawaii to Iraq by Stephen Kinzer ; Longitude and Empire: How Captain Cook's Voyages Changed the World by Brian W. Richardson ; Pacific Encounters: Art & Diversity in Polynesia 1760-1860 by Steven Hooper ; All Men Are Brothers: The Life & Times of Francis Williams Damon by Paul Berry ; Broken Trust: Greed, Mismanagement, & Political Manipulation at America's Largest Charitable Trust by Samuel P. King and Randall W. Roth ; Crowning the Nice Girl: Gender, Ethnicity, and Culture in Hawai'i's Cherry Blossom Festival by Christine R. Yano ; Combat Chaplain: The Personal Story of the World War II Chaplain of the Japanese American 100th Battalion by Israel A. S. Yost ; Hawaiian Volcanoes by Clarence Edward Dutton ; Reworking Race: The Making of Hawaii's Interracial Labor Movement by Moon-Kie Jung ; Islands in a Far Sea: The Fate of Nature in Hawai'i by John L. Culliney