Comparative study of I-V characteristics of the ICB deposited Ag\-Si(111) and Ag\p-Si(100) Schottky junctions

The room temperature I-U characteristics of the ionized cluster beam, ICB, deposited Ag\-Si(111) and Ag\p-Si(100) Schottky barrier junctions, for non zero Ag ions acceleration voltage U_a > 0 V, have been investigated. The effective Schottky barrier height (SBH) is observed to decrease if Ag is deposited on n-doped Si substrate but for Ag\p-Si junction shows an increase, relatively to the corresponding SBH values of U_a = 0 V ICB deposited junctions, respectively.     

A topology optimization approach using VOF method

Topology optimization methods with continuous design variables obtained by the homogenization formula or the solid isotropic microstructure with penalty (SIMP) model are widely used in the layout of structures. In the implementation of these approaches, one must take into account several issues, e.g., irregularity of the problem, occurrence of the checkerboard pattern, and intermediate density. To suppress these phenomena, the employment of additional strategies such as the perimeter control or the filtering method will be required. In this paper, a topology optimization method which can eliminate these difficulties is developed based on the volume of fluid (VOF) method. In the method, shape design is described in terms of the VOF function. Since this function is defined by a volume fraction of material occupying each element, it can be recognized as a continuous material density in the SIMP model. Within the framework of the VOF analysis, the topology optimization procedure is reduced to a convection motion of the material density governed by a Hamilton–Jacobi equation as in the level set method. Through numerical examples, the validity of the proposed method is investigated.     

Prediction of Chronic Inflammation for Inhaled Particles: the Impact of Material Cycling and Quarantining in the Lung Epithelium

On a daily basis, people are exposed to a multitude of health-hazardous airborne particulate matter with notable deposition in the fragile alveolar region of the lungs. Hence, there is a great need for identification and prediction of material-associated diseases, currently hindered due to the lack of in-depth understanding of causal relationships, in particular between acute exposures and chronic symptoms. By applying advanced microscopies and omics to in vitro and in vivo systems, together with in silico molecular modeling, it is determined herein that the long-lasting response to a single exposure can originate from the interplay between the newly discovered nanomaterial quarantining and nanomaterial cycling between different lung cell types. This new insight finally allows prediction of the spectrum of lung inflammation associated with materials of interest using only in vitro measurements and in silico modeling, potentially relating outcomes to material properties for a large number of materials, and thus boosting safe-by-design-based material development. Because of its profound implications for animal-free predictive toxicology, this work paves the way to a more efficient and hazard-free introduction of numerous new advanced materials into our lives.     

Antioxidant and antimicrobial activity of guarana seed extracts

The antioxidant and antibacterial activities of guarana (Paullinia cupana) seed extracts were determined. The seeds were extracted with water, methanol, 35% acetone and 60% ethanol at room (T_R) and at boiling (T_B) temperature of solvent.     

Extraction of active ingredients from green tea (Camellia sinensis): Extraction efficiency of major catechins and caffeine

The effect of different extraction set-ups that influence the extraction efficiency of catechins and caffeine from green tea leaves (variety Fanning Belas, China) were studied using different aqueous and pure solvents (acetone, ethanol, methanol, acetonitrile, water), different temperatures (60, 80, 95 and 100 °C) and times (5–240 min). Raw extracts were analysed for contents of major catechins (EC, EGC, ECG, EGCG), caffeine, proanthocyanidins and flavonols (myricetin, caempherol, quercetin). Starting material was found to contain 191 g major catechins/kg material, 36 g caffeine/kg material and 5.2 g flavonols/kg material on a dry mass basis. The content of major catechins in green tea extracts varied from approximately 280–580 g/kg dry extract, with extraction efficiencies of major catechins varying from 61% to almost 100%. Content of caffeine in extract was in the range of 75 g/kg, where its extraction efficiency varied from 62% to 76%. Average extraction yield was 30% with exceptions when using pure acetone and acetonitrile, where extraction yield was about 3%. Contents of flavonols and proanthocyanidins were in the ranges 6–20 and 12–19 g/kg, respectively. Different extraction procedures with water were also investigated and optimal conditions determined: maximum achieved extraction efficiency of catechins with water was obtained at 80 °C after 20 min (97%) and at 95 °C after 10 min of extraction (90%). Degradation of catechins was observed at higher extraction temperatures and with prolonged extraction times. Using a lower ratio of solvent to material, extraction efficiencies were increased by applying a multi-step extraction procedure. Optimal extraction procedure was then performed using decaffeinated green tea leaves, which were obtained by high-pressure extraction with CO₂, when 98% of caffeine was selectively isolated without significant impact on valuable catechins.     

The Relationship between COVID-19 and Hypothalamic–Pituitary–Adrenal Axis: A Large Spectrum from Glucocorticoid Insufficiency to Excess—The CAPISCO International Expert Panel

Coronavirus disease 2019 (COVID-19) is a highly heterogeneous disease regarding severity, vulnerability to infection due to comorbidities, and treatment approaches. The hypothalamic–pituitary–adrenal (HPA) axis has been identified as one of the most critical endocrine targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that might significantly impact outcomes after infection. Herein we review the rationale for glucocorticoid use in the setting of COVID-19 and emphasize the need to have a low index of suspicion for glucocorticoid-induced adrenal insufficiency, adjusting for the glucocorticoid formulation used, dose, treatment duration, and underlying health problems. We also address several additional mechanisms that may cause HPA axis dysfunction, including critical illness-related corticosteroid insufficiency, the direct cytopathic impacts of SARS-CoV-2 infection on the adrenals, pituitary, and hypothalamus, immune-mediated inflammations, small vessel vasculitis, microthrombotic events, the resistance of cortisol receptors, and impaired post-receptor signaling, as well as the dissociation of ACTH and cortisol regulation. We also discuss the increased risk of infection and more severe illness in COVID-19 patients with pre-existing disorders of the HPA axis, from insufficiency to excess. These insights into the complex regulation of the HPA axis reveal how well the body performs in its adaptive survival mechanism during a severe infection, such as SARS-CoV-2, and how many parameters might disbalance the outcomes of this adaptation.