Metal–organic frameworks (MOFs) containing redox active linkers have led to hybrid compounds exhibiting high electrical conductivity, which enables their use in applications in electronics and ...electrocatalysis. While many computational studies predict two-dimensional (2D) MOFs to be metallic, the majority of experiments show decreasing conductivity on cooling, indicative of a gap in the electronic band structure. To date, only a handful of MOFs have been reported that exhibit increased electrical conductivity upon cooling indicative of a metallic character, which highlights the need for a better understanding of the origin of the conductivity. A 2D MOF containing iron bis(dithiolene) motifs was recently reported to exhibit semiconducting behavior with record carrier mobility. Herein, we report that high crystallinity and the elimination of guest species results in an iron 2,3,6,7,10,11-tripheylenehexathiolate (THT) MOF, FeTHT, exhibiting a complex transition from semiconducting to metallic upon cooling, similar to what was shown for the analogous CoTHT. Remarkably, exposing the FeTHT to air significantly influences the semiconducting-to-metallic transition temperature (100 to 300 K) and ultimately results in a material showing metallic-like character at, and above, room temperature. This study indicates these materials can tolerate a substantial degree of doping that ultimately results in charge delocalization and metallic-like conductivity, an important step toward enabling their use in chemiresistive sensing and optoelectronics.
Cutaneous sclerosis occurs in 20% of patients with chronic graft-versus-host disease (GVHD) and can compromise mobility and quality of life.
We conducted a prospective, multicenter, randomized, ...two-arm phase II crossover trial of imatinib (200 mg daily) or rituximab (375 mg/m(2) i.v. weekly × 4 doses, repeatable after 3 months) for treatment of cutaneous sclerosis diagnosed within 18 months (NCT01309997). The primary endpoint was significant clinical response (SCR) at 6 months, defined as quantitative improvement in skin sclerosis or joint range of motion. Treatment success was defined as SCR at 6 months without crossover, recurrent malignancy or death. Secondary endpoints included changes of B-cell profiles in blood (BAFF levels and cellular subsets), patient-reported outcomes, and histopathology between responders and nonresponders with each therapy.
SCR was observed in 9 of 35 26%; 95% confidence interval (CI); 13%-43% participants randomized to imatinib and 10 of 37 (27%; 95% CI, 14%-44%) randomized to rituximab. Six (17%; 95% CI, 7%-34%) patients in the imatinib arm and 5 (14%; 95% CI, 5%-29%) in the rituximab arm had treatment success. Higher percentages of activated B cells (CD27(+)) were seen at enrollment in rituximab-treated patients who had treatment success (P = 0.01), but not in imatinib-treated patients.
These results support the need for more effective therapies for cutaneous sclerosis and suggest that activated B cells define a subgroup of patients with cutaneous sclerosis who are more likely to respond to rituximab.
In Canada, the prevalence of diabetes has seen the greatest relative increase in young adulthood, where the disorder is severely pathological compared to later-onset. Still, few prognostic models ...have been developed to screen young adults for dysglycemia risk and boost early identification and intervention. We sought to establish predictors of dysglycemia risk among young Canadian adults (aged 18-39) and evaluate their utility in identifying high-risk individuals. The Canadian Diabetes Risk Questionnaire (CANRISK) study collected questionnaire, anthropometric, and oral glucose tolerance test (OGTT) data from a large, multiethnic convenience sample of Canadians over two phases. Young adults with diagnosed diabetes, missing OGTT data, or pregnant were excluded. Potential factors that modestly predicted (p<0.20) dysglycemia status (FPG≥6.1mmol/L or 2h-PG≥7.8mmol/L) were entered into a lenient stepwise function, producing a young adult-specific model; risk scores were developed from adjusted odds ratios. Discriminatory ability was assessed by optimism-corrected area under the curve (AUC) via bootstrapping and goodness-of-fit by Hosmer-Lemeshow (H-L) test and calibration plot. More than half of the 3334 participants were female (62.4%), non-white (79.2%), less than 25kg/m2 (50.7%), and reported a family history of diabetes (55.4%); based on OGTT results, 7.3% were dysglycemic. The young adult-specific model displayed an adjusted AUC of 72.9%, and reasonable goodness-of-fit (H-L p=0.49). Model performance was similar when run sex-specifically (males: unadjusted AUC of 72.1%, H-L p=0.67; females: 73.6%, p=0.67). Employing a cut-point of 22, the tool displayed high sensitivity (78.8%) but low specificity (54.0%). Only 3% of those identified as low risk by the tool were misclassified.
This young adult-specific risk score shows promise to identify high-risk individuals in a multiethnic Canadian sample. Additional studies are needed to assess its generalizability to new datasets.
Disclosure
S.A. Srugo: None. Y. Jiang: None. H.I. Morrison: None. M.M. deGroh: None.
Neighbourhood greenness has been frequently associated with improved mental health in adulthood, yet its impact among youth is less clear. Additionally, though youth spend large portions of time at ...school, no study has investigated associations between school-based measures of greenness and students' mental health in Canada. We addressed this gap by linking participant responses from the 2016-2017 Ontario Student Drug Use and Health Survey to school-based features of the built environment. Our analyses included 6313 students, ages 11-20. Measures of greenness were the mean and max of the annual mean Normalized Difference Vegetation Index within 500 m and 1000 m from the centroid of the school postal code. Measures of mental health included: serious psychological distress (Kessler 6-item Psychological Distress Scale), self-rated mental health (using a five-point Likert scale), suicide ideation, and suicide attempt. In our study population, the prevalence of serious psychological distress and low self-rated mental health was 16.7% and 20.3%, respectively. Suicide ideation was reported by 13.5% of participants, while 3.7% reported a suicide attempt. Quantity of greenness was similar between schools in the lower and upper quartiles. In logistic regressions, we found no association between objective school-based greenness and mental health, as assessed by multiple measures, both before and after adjustment. Null findings held true after stratification by season, as well. Whether other characteristics of school greenness (such as type, quality, or access and use) are more impactful to students' mental health should be a focus of future analyses.
The metal to insulator transition of NbO2 has been predicted to be a result of a structural phase transition (SPT) governed by Peierls physics. However, direct observation of the SPT using ...experimental techniques is still restricted by the extremely high transition temperature (810 °C) and the proclivity for NbO2 to oxidize into Nb2O5 above 400 °C when exposed to air. Here, we address these issues and employ temperature-dependent X-ray spectroscopy to describe the SPT of NbO2 from the bulk to surface. Temperature-dependent extended X-ray absorption fine structure spectroscopy (T-EXAFS) reveals a gradual weakening of the bulk Nb dimers over a large temperature range, which is indicative of a second-order Peierls mechanism. From these measurements, we determine the critical dimer distance to be 2.77 Å. Our T-EXAFS observations are supported by density functional theory of the phonon dispersion and the electronic density of states of NbO2, which conclude that the dimerization is responsible for the insulating phase. The dimerization does not extend to the topmost layers, where an oxygen rich surface reconstruction is preferred irrespective of temperature even in extremely reducing environments; changes in the low-energy electron diffraction patterns are attributed to oxygen concentration and are independent of the underlying bulk phase transitions of NbO2.
Dysglycemia, including prediabetes and type 2 diabetes, is dangerous and widespread. Yet, the condition is transiently reversible and sequelae preventable, prompting the use of prediction algorithms ...to quickly assess dysglycemia status through self-reported data. However, as current algorithms have largely been developed in older populations, their application to younger adults is uncertain considering associations between risk factors and dysglycemia vary by age. We sought to identify sex-specific predictors of current dysglycemia among young adults and evaluate their ability to screen for prediabetes and undiagnosed diabetes. We analyzed 2005–2014 data from the National Health and Nutrition Examination Survey for 3251 participants aged 20–39, who completed an oral glucose tolerance test (OGTT), had not been diagnosed with diabetes, and, for females, were not pregnant. Sex-specific stepwise logistic models were fit with predictors identified from univariate analyses. Risk scores were developed using adjusted odds ratios and model performance was assessed using area under the curve (AUC) measures. The OGTT identified 906 (27.9%) and 78 (2.4%) participants with prediabetes or undiagnosed diabetes, respectively. Predictors of dysglycemia status for males were BMI, age, race, and first-degree family history of diabetes, and, in addition to those, education, delivered baby weight, waist circumference, and vigorous physical activity for females. Our male- and female-specific models demonstrated improved validity to assess dysglycemia presence among young adults relative to the widely-used American Diabetes Association test (AUC = 0.69 vs. 0.61; 0.92 vs. 0.71, respectively). Thus, age-specific scoring algorithms employing questionnaire data show promise and are effective in identifying dysglycemia among young adults.
•1 in 3 young adults had objectively-assessed dysglycemia (prediabetes or diabetes).•Adiposity was the strongest predictor of dysglycemia for both sexes.•Fewer factors strongly predicted dysglycemia status in young adult males vs. females.•The popular American Diabetes Association test performed modestly in this age group.•Sex-specific scores for young adults improved model discrimination and calibration.
Straining the vanadium dimers along the rutile c‐axis can be used to tune the metal‐to‐insulator transition (MIT) of VO2 but has thus far been limited to TiO2 substrates. In this work VO2/MgF2 ...epitaxial films are grown via molecular beam epitaxy (MBE) to strain engineer the transition temperature (TMIT). First, growth parameters are optimized by varying the synthesis temperature of the MgF2 (001) substrate (TS) using a combination of X‐ray diffraction techniques, temperature dependent transport, and soft X‐ray photoelectron spectroscopy. It is determined that TS values greater than 350 °C induce Mg and F interdiffusion and ultimately the relaxation of the VO2 layer. Using the optimized growth temperature, VO2/MgF2 (101) and (110) films are then synthesized. The three film orientations display MITs with transition temperatures in the range of 15–60 °C through precise strain engineering.
The MBE growth optimization of high quality VO2/MgF2 epitaxial thin films is elaborated. A growth temperature of 300 °C is found to achieve the highest degree of epitaxial strain while suppressing substrate interdiffusion which occurs at higher temperatures. Effect of thickness, substrate orientation, and crystalline size on the digital switching of strain engineered VO2 thin films is investigated.
The Canadian prevalence and incidence of diabetes has increased by the greatest extent in young adulthood. The original Canadian Diabetes Risk Questionnaire (CANRISK) was created to assess ...dysglycemia risk among adults ≥40 years of age, but it has not been validated among younger adults. Furthermore, it is unclear whether a young adult-specific risk score would better identify dysglycemia in this age group.
Analyses were done on participants who completed the self-administered CANRISK and underwent anthropometric and blood glucose measurements, were 18 to 39 years of age, were not pregnant and had no previous diabetes diagnosis. A risk model was generated from a lenient stepwise function fit with predictors identified through univariate analyses. Risk scores were produced from adjusted odds ratios. Model performance was internally validated using bootstrap methods and compared with the original CANRISK prognostic tool.
Of the 3,334 participants included in the study, 194 (5.8%) and 51 (1.5%) were living with prediabetes or undiagnosed diabetes, respectively. The model displayed an area under the curve of 73.0%, adjusted to 72.9% after bootstrapping; however, using the original CANRISK model resulted in similar results (area under the curve, 71.4%). Sensitivity and specificity of the new and original models were also comparable (78.8% vs 77.1% and 54.0% vs 55.0%, respectively).
The original CANRISK score performed well among young adults, even when compared with a young adult-specific model. We suggest that the cut point be lowered for young adults and the tool be permitted for use in this age group.
La prévalence et l’incidence du diabète au Canada ont connu leur plus forte augmentation chez les jeunes adultes. Le questionnaire CANRISK (Canadian Diabetes Risk Questionnaire) a été créé pour évaluer le risque de dysglycémie chez les adultes ≥ 40 ans, mais n’a pas été validé auprès d’adultes plus jeunes. De plus, on ignore si le score de risque propre aux jeunes adultes permettrait de mieux détecter la dysglycémie chez ces adultes.
Des analyses ont été effectuées auprès des participants qui avaient rempli l’auto-questionnaire CANRISK et subi des mesures anthropométriques et glycémiques, avaient de 18 à 39 ans, n’étaient pas des femmes enceintes et n’avaient jamais reçu de diagnostic de diabète. Un modèle de risque a été généré par l’ajustement modéré des opérations séquentielles à l’aide des prédicteurs déterminés par les analyses univariées. Les scores de risque ont été produits à partir des ratios d’incidence approchés ajustés. La performance du modèle a fait l’objet d’une validation interne à l’aide de méthodes d’auto-amorçage et d’une comparaison à l’aide de l’outil pronostique original CANRISK.
Parmi les 3334 participants de l’étude, 194 (5,8 %) et 51 (1,5 %) avaient respectivement un prédiabète ou un diabète non diagnostiqué. Le modèle affichait une surface sous la courbe de 73,0 %, ajustée à 72,9 % après l’auto-amorçage. Toutefois, l’utilisation du modèle original CANRISK entraînait des résultats similaires (surface sous la courbe, 71,4 %). La sensibilité et la spécificité des nouveaux modèles et des modèles originaux étaient également comparables (78,8 % vs 77,1 % et 54,0 % vs 55,0 %, de façon respective).
Le score original CANRISK offrait une bonne performance chez les jeunes adultes, même lorsqu’on le comparait au modèle propre aux jeunes adultes. Nous suggérons que le seuil soit abaissé chez les jeunes adultes et que l’utilisation de l’outil dans ce groupe d’âge soit approuvée.
The discovery of analog LixNbO2 memristors revealed a promising new memristive mechanism wherein the diffusion of Li+ rather than O2− ions enables precise control of the resistive states. However, ...directly correlating lithium concentration with changes to the electronic structure in active layers remains a challenge and is required to truly understand the underlying physics. Chemically delithiated single crystals of LiNbO2 present a model system for correlating lithium variation with spectroscopic signatures from operando soft x-ray spectroscopy studies of device active layers. Using electronic structure modeling of the x-ray spectroscopy of LixNbO2 single crystals, we demonstrate that the intrinsic memristive behavior in LixNbO2 active layers results from field-induced degenerate p-type doping. We show that electrical operation of LixNbO2-based memristors is viable even at marginal Li deficiency and that the analog memristive switching occurs well before the system is fully metallic. This study serves as a benchmark for material synthesis and characterization of future LixNbO2-based memristor devices and suggests that valence change switching is a scalable alternative that circumvents the electroforming typically required for filamentary-based memristors.
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