It has been known for decades that the application of pulsed direct current can significantly enhance the formability of metals. However, the detailed mechanisms of this effect have been difficult to ...separate from simple Joule heating. Here, we study the electroplastic deformation of Ti-Al (7 at.% Al), an alloy that is uniquely suited for uncoupling this behaviour because, contrary to most metals, it has inherently lower ductility at higher temperature. We find that during mechanical deformation, electropulsing enhances cross-slip, producing a wavy dislocation morphology, and enhances twinning, which is similar to what occurs during cryogenic deformation. As a consequence, dislocations are prevented from localizing into planar slip bands that would lead to the early failure of the alloy under tension. Our results demonstrate that this macroscopic electroplastic behaviour originates from defect-level microstructural reconfiguration that cannot be rationalized by simple Joule heating.
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GEOZS, IJS, IMTLJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK, ZAGLJ
Structural alloys are often strengthened through the addition of solute atoms. However, given that solute atoms interact weakly with the elastic fields of screw dislocations, it has long been ...accepted that solution hardening is only marginally effective in materials with mobile screw dislocations. By using transmission electron microscopy and nanomechanical characterization, we report that the intense hardening effect of dilute oxygen solutes in pure α-Ti is due to the interaction between oxygen and the core of screw dislocations that mainly glide on prismatic planes. First-principles calculations reveal that distortion of the interstitial sites at the screw dislocation core creates a very strong but short-range repulsion for oxygen that is consistent with experimental observations. These results establish a highly effective mechanism for strengthening by interstitial solutes.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
The heritability of Major Depressive Disorder (MDD) has been estimated at 37% based largely on twin studies that rely on contested assumptions. More recently, the heritability of MDD has been ...estimated on large populations from registries such as the Swedish, Finnish, and Chinese cohorts. Family-based designs utilise a number of different relationships and provide an alternative means of estimating heritability. Generation Scotland: Scottish Family Health Study (GS:SFHS) is a large (n = 20,198), family-based population study designed to identify the genetic determinants of common diseases, including Major Depressive Disorder. Two thousand seven hundred and six individuals were SCID diagnosed with MDD, 13.5% of the cohort, from which we inferred a population prevalence of 12.2% (95% credible interval: 11.4% to 13.1%). Increased risk of MDD was associated with being female, unemployed due to a disability, current smokers, former drinkers, and living in areas of greater social deprivation. The heritability of MDD in GS:SFHS was between 28% and 44%, estimated from a pedigree model. The genetic correlation of MDD between sexes, age of onset, and illness course were examined and showed strong genetic correlations. The genetic correlation between males and females with MDD was 0.75 (0.43 to 0.99); between earlier (≤ age 40) and later (> age 40) onset was 0.85 (0.66 to 0.98); and between single and recurrent episodic illness course was 0.87 (0.72 to 0.98). We found that the heritability of recurrent MDD illness course was significantly greater than the heritability of single MDD illness course. The study confirms a moderate genetic contribution to depression, with a small contribution of the common family environment (variance proportion = 0.07, CI: 0.01 to 0.15), and supports the relationship of MDD with previously identified risk factors. This study did not find robust support for genetic differences in MDD due to sex, age of onset, or illness course. However, we found an intriguing difference in heritability between recurrent and single MDD illness course. These findings establish GS:SFHS as a valuable cohort for the genetic investigation of MDD.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The importance of 1,5‐O⋅⋅⋅chalcogen (Ch) interactions in isochalcogenourea catalysis (Ch=O, S, Se) is investigated. Conformational analyses of N‐acyl isochalcogenouronium species and comparison with ...kinetic data demonstrate the significance of 1,5‐O⋅⋅⋅Ch interactions in enantioselective catalysis. Importantly, the selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes including nitronate conjugate addition and formal 4+2 cycloadditions. A gram‐scale synthesis of the most active selenium analogue was developed using a previously unreported seleno‐Hugerschoff reaction, allowing the challenging kinetic resolutions of tertiary alcohols to be performed at 500 ppm catalyst loading. Density functional theory (DFT) and natural bond orbital (NBO) calculations support the role of orbital delocalization (occurring by intramolecular chalcogen bonding) in determining the conformation, equilibrium population, and reactivity of N‐acylated intermediates.
Conformational and computational analyses of N‐acyl isochalcogenouronium species and comparison with kinetic data demonstrate the significance of 1,5‐O⋅⋅⋅Ch interactions in enantioselective catalysis. The selenium analogue demonstrates enhanced rate and selectivity profiles across a range of reaction processes compared to its oxygen and sulfur congeners.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
CONTEXT Clinicians order blood cultures liberally among patients in whom bacteremia is suspected, though a small proportion of blood cultures yield true-positive results. Ordering blood cultures ...inappropriately may be both wasteful and harmful. OBJECTIVE To review the accuracy of easily obtained clinical and laboratory findings to inform the decision to obtain blood cultures in suspected bacteremia. DATA SOURCES AND STUDY SELECTION A MEDLINE and EMBASE search (inception to April 2012) yielded 35 studies that met inclusion criteria for evaluating the accuracy of clinical variables for bacteremia in adult immunocompetent patients, representing 4566 bacteremia and 25 946 negative blood culture episodes. DATA EXTRACTION Data were extracted to determine the prevalence and likelihood ratios (LRs) of findings for bacteremia. DATA SYNTHESIS The pretest probability of bacteremia varies depending on the clinical context, from low (eg, cellulitis: 2%) to high (eg, septic shock: 69%). Elevated temperatures alone do not accurately predict bacteremia (for ≥38°C >100.3°F, LR, 1.9 95% CI, 1.4-2.4; for ≥38.5°C >101.2°F, LR, 1.4 95% CI, 1.1-2.0), nor does isolated leukocytosis (LR, <1.7). The severity of chills graded on an ordinal scale (shaking chills, LR, 4.7; 95% CI, 3.0-7.2) may be more useful. Both the systemic inflammatory response syndrome (SIRS) and a multivariable decision rule with major and minor criteria are sensitive (but not specific) predictors of bacteremia (SIRS, negative LR, 0.09 95% CI, 0.03-0.26; decision rule, negative LR, 0.08 95% CI, 0.04-0.17). CONCLUSIONS Blood cultures should not be ordered for adult patients with isolated fever or leukocytosis without considering the pretest probability. SIRS and the decision rule may be helpful in identifying patients who do not need blood cultures. These conclusions do not apply to immunocompromised patients or when endocarditis is suspected.
Background. We assessed the impact of infectious disease (ID) consultation on management and outcome in patients with Staphylococcus aureus bacteremia (SAB). Methods. A retrospective cohort study ...examined consecutive SAB patients from 6 academic and community hospitals between 2007 and 2010. Quality measures of management including echocardiography, repeat blood culture, removal of infectious foci, and antibiotic therapy were compared between ID consultation (IDC) and no ID consultation (NIDC) groups. A competing risk model with propensity score adjustment was used to compare in-hospital mortality and time to discharge. Results. Of 847 SAB patients, 506 (60%) patients received an ID consultation and 341 (40%) patients did not. Echocardiography was done for 371 (73%) IDC and 191 (56%) NIDC patients (P < .0001) in hospital. Blood cultures were repeated within 2–4 days of bacteremia in 207 (41%) IDC and 107 (31%) NIDC patients (P = .0058). The infectious foci removal rate was not statistically different between the 2 groups. For empiric therapy, 474 (94%) IDC and 297 (87%) NIDC patients received appropriate antibiotics (P = .0013). For patients who finished the planned course of antibiotics, 285 of 422 (68%) IDC and 141 of 262 (54%) NIDC patients received the appropriate duration of antibiotic therapy (P = .0004). In hospital, 204 (24%) patients died: 104 of 506 (21%) IDC and 100 of 341 (29%) NIDC patients. Matched by propensity score, ID consultation had a subdistribution hazard ratio of 0.72 (95% confidence interval CI, .52–.99; P = .0451) for in-hospital mortality and 1.28 (95% CI, 1.06–1.56; P = .0109) for being discharged alive. Conclusions. ID consultation is associated with better adherence to quality measures, reduced in-hospital mortality, and earlier discharge in patients with SAB.
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Trending Cardiovascular Nutrition Controversies Freeman, Andrew M., MD; Morris, Pamela B., MD; Barnard, Neal, MD ...
Journal of the American College of Cardiology,
03/2017, Volume:
69, Issue:
9
Journal Article
Peer reviewed
Open access
Abstract The potential cardiovascular benefits of several trending foods and dietary patterns are still incompletely understood, and nutritional science continues to evolve. However, in the meantime, ...a number of controversial dietary patterns, foods, and nutrients have received significant media exposure and are mired by hype. This review addresses some of the more popular foods and dietary patterns that are promoted for cardiovascular health to provide clinicians with accurate information for patient discussions in the clinical setting.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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