Dionea (Switzerland)

The oxygen reduction reaction (ORR), which converts molecular oxygen (O2) into water (H2O), is critical for renewable energy transformation processes. However, its industrial application is hindered by long conversion times. Recent studies suggest that transition metal clusters deposited on graphene are promising candidates for ORR catalysis. In this work, we employed density functional theory (DFT) calculations to explore the thermodynamically most stable energy profile of the ORR on pentamer metal clusters (Fe5, Co5, and Pt5) supported on undoped graphene and nitrogen-doped graphene (for Fe5), under standard electrochemical conditions (pH = 0 and U = 0). Both the "standard" intermediates (*OOH, *O, *OH) and the "unconventional" intermediates (*O*OH, *OH*OH) were studied, analyzing thermodynamic stability, adsorption energies, and the influence of the implicit water solvent. Our results reveal that the inclusion of "unconventional" intermediates significantly alters the reaction thermodynamics, presenting a new pathway that is energetically more favorable than the classical one. Catalytic performance predictions, based on the theoretical overpotential (ηORR), indicate that the four catalysts exhibit good stability and high activity in both reduction mechanisms. In particular, Fe5@NGr shows the best catalytic performance in the "unconventional" mechanism, with an ηORR close to zero. This study, for the first time, demonstrates how the metal cluster and the support's electronic and structural properties influence the stability of ORR intermediates and catalytic performance. The improved performance of Fe5@NGr in the "unconventional" mechanism highlights the importance of selecting the right metal and engineering the graphene support, particularly through N-doping, for the rational design of low-cost, high-performance catalysts.

Background: Diabetes mellitus (DM) is a metabolic group with characteristic hyperglycemia that occurs due toabnormal insulin secretion, insulin action, or both. DM is often called the silent killer because the patients knowthey has DM only after the patient experiencing complications and manifestations. It is estimated that 30-70% of DM patients experience skin manifestations during the disease process. The relationship between the appearance of skin manifestations with diabetes mellitus is not yet known, but it is suspected due to chronic hyperglycemia and abnormalities of the immune system.Objective: To determine skin diseases in patients with type 2 diabetes at General Hospital Dr. Pirngadi Medan.Methods: This research was a descriptive study with a cross-sectional study design conducted at Dr. GeneralHospital Pirngadi Medan. Data collection was carried out through 29 medical records of patients with diabetesmellitus from January 2018 to December 2018. Samples were selected by total sampling.Results: From 29 samples studied, there were six types of skin manifestations. The most common skinmanifestations are Diabetic Ulcer (62.07%), followed by Steven Johnson Syndrome and diabetic gangrene, which both are equally 13.80%. The other skin manifestations are herpes zoster, gluteal abscess, and bullous pemphigoid (3.44%).Conclusion: The most common manifestation of the skin in patients with type 2 DM is Diabetic Ulcer.

Surface pollen deposition at five sites (Kichikol, Karakol, Nishneye and Verkhneye Ozero, and Bakaly) in four different forest types ( Juniperus , Picea, Juglans and mixed forests) in Kyrgyzstan have been investigated to assess the relationship between modern vegetation and pollen composition in order to calibrate the pollen representation. Vegetation surveys with an estimation of the tree-crown cover (%) were made in 10 m × 10 m plots to relate the vegetation to surface pollen of moss polsters. Correlation calculations show a close relationship between vegetation (tree-crown cover) and pollen for the Juniperus site (eg, r2 = 0.76 between crown cover and arboreal pollen, AP) and the Picea site ( r2 = 0.85), whereas the linkage is weaker at the Juglans site ( r 2 = 0.35) and in mixed forests ( r2 = 0.32). The results of the surface samples of moss polsters are compared and discussed with surface samples of lake sediments that were taken at the same locations. We use vegetational maps from around the lakes to discuss the link between vegetation and pollen at extra-local scales (800 m around the sites). These comparisons show that AP underestimates the effective tree cover around all sites, with in extreme cases densely forested areas corresponding to AP values as low as <60; 30%. We explain this finding by the prevalent background pollen load that derives from the dry lowland and slope steppes ( Artemisia, Chenopodiaceae, Poaceae). Our investigation may improve the reconstruction of Quaternary vegetation and climate history of these forest belts in Kyrgyzstan (Central Asia) on the basis of fossil pollen assemblages from mire and lake sediments. It provides new insights into the pollen reflection of forest isles (eg, on humid slopes or mountain tops) that are surrounded by continental steppes; a vegetational situation that may be used as an analogue for the conditions during the full glacial in Eurasia and Northern America.