49 research outputs found
Controlling Hydrocarbon (De)Hydrogenation Pathways with Bifunctional PtCu Single-Atom Alloys
The conversions of surface-bound alkyl groups to alkanes and alkenes are important steps in many heterogeneously catalyzed reactions. On the one hand, while Pt is ubiquitous in industry because of its high activity toward C-H activation, many Pt-based catalysts tend to overbind reactive intermediates, which leads to deactivation by carbon deposition and coke formation. On the other hand, Cu binds intermediates more weakly than Pt, but activation barriers tend to be higher on Cu. We examine the reactivity of ethyl, the simplest alkyl group that can undergo hydrogenation and dehydrogenation via β-elimination, and show that isolated Pt atoms in Cu enable low-temperature hydrogenation of ethyl, unseen on Cu, while avoiding the decomposition pathways on pure Pt that lead to coking. Furthermore, we confirm the predictions of our theoretical model and experimentally demonstrate that the selectivity of ethyl (de)hydrogenation can be controlled by changing the surface coverage of hydrogen
Treatment of Cleft lip & Palate Related Maxillary Hypoplasia with RED System: Case Report
Clefts of the lip and palate present one of the most challenging congenital disorders to the orthodontists and craniofacial surgeons. A common finding is maxillary hypoplasia. Current case report presents the treatment of a 19 years old female unilateral cleft lip and palate patient characterized with maxillary constriction, retrusion and severe underjet. The case has been successfully treated with fixed appliance therapy and rigid external distraction and relapse at the end of treatment is minimal. However, longer follow-ups are required to assess the exact amount of stability
Mental health prevalence and predictors among university students in nine countries during the COVID-19 pandemic: a cross-national study
The student population has been highly vulnerable to the risk of mental health deterioration during the coronavirus disease (COVID-19) pandemic. This study aimed to reveal the prevalence and predictors of mental health among students in Poland, Slovenia, Czechia, Ukraine, Russia, Germany, Turkey, Israel, and Colombia in a socioeconomic context during the COVID-19 pandemic. The study was conducted among 2349 students (69% women) from May–July 2020. Data were collected by means of the Generalized Anxiety Disorder (GAD-7), Patient Health Questionnaire (PHQ-8), Perceived Stress Scale (PSS-10), Gender Inequality Index (GII), Standard & Poor’s Global Ratings, the Oxford COVID-19 Government Response Tracker (OxCGRT), and a sociodemographic survey. Descriptive statistics and Bayesian multilevel skew-normal regression analyses were conducted. The prevalence of high stress, depression, and generalized anxiety symptoms in the total sample was 61.30%, 40.3%, and 30%, respectively. The multilevel Bayesian model showed that female sex was a credible predictor of PSS-10, GAD-7, and PHQ-8 scores. In addition, place of residence (town) and educational level (first-cycle studies) were risk factors for the PHQ-8. This study showed that mental health issues are alarming in the student population. Regular psychological support should be provided to students by universities
Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins
Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe
Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature
The effects of the zinc supplementation and weight trainings on the testosterone levels
Aim. The purpose of this study, it has been aimed to examine the effects of zinc supplementation applied with weight trainings on the testosterone levels in sedentary individuals and athletes. Materials and Methods. As methods of work it was selected 40 male, 20 sedentary male and 20 male who do physical exercises regularly, participated in the study. The participants are divided equally into 4 groups. The groups are constituted in that way: 1st Group: Control Group (S), 2nd Group: Sedentary Group which is supplied with Zinc (Z), 3rd Group: Training Group which is supplied with Zinc (ZT) and 4th Group: Athletes' Group who performs the weight training (T). The total testosterone and free testosterone values of the participants were measured from the blood samples which were drawn from the participants at the beginning and at the end of the 6-week training period. Results. Like results, has been asserted that the total and free testosterone values of the groups which are supplied with Zinc and perform weight training have increased depending on training and supplementation. Conclusion. In conclusion consequently it has been determined that 6-week zinc supplementation and weight training increase the testosterone levels. Accordingly, it may be said that this implementation contributes to the performance. © 2017 South Ural State University - Institute of Sport, Tourism and Service. All rights reserved
Thymoquinone Inhibits Proliferation and Migration of MDA-MB-231 Triple Negative Breast Cancer Cells by Suppressing Autophagy and Beclin-1 and LC3.
Background: Triple Negative Breast Cancer (TNBC) is an aggressive and highly heterogeneous subtype of breast cancer associated with poor prognosis. A better understanding of the biology of this complex cancer is needed to develop novel therapeutic strategies for the improvement of patient survival. We have previously demonstrated that Thymoquinone (TQ), the major phenolic compound found in Nigella sativa, induces anti-proliferative and anti-metastatic effects and inhibits in vivo tumor growth in orthotopic TNBC models in mice. Also, we have previously shown that Beclin-1 and LC3 autophagy genes contributes to TNBC cell proliferation, migration and invasion, suggesting that Beclin-1 and LC3 genes provide proto-oncogenic effects in TNBC. However, the role of Beclin-1 and LC3 in mediating TQ-induced anti-tumor effects in TNBC is not known