A first-principles study of Zn induced liquid metal embrittlement at bcc and fcc grain boundaries

Zn induced liquid metal embrittlement (LME) is a major concern in particular for advanced high strength steels, which often contain a significant amount of austenite compared to established steel grades. Using density functional theory (DFT) calculations we, therefore, compare the behaviour of Zn in ferrite (bcc) and austenite (fcc) grain boundaries (GBs) with different magnetic ordering to investigate the role of crystal structure as well as magnetism in LME. We address the performance of DFT based paramagnetic calculations by utilizing the spin space averaging relaxation approach. Our results show that both magnetic and elastic contributions have significant influence towards segregation and embrittling behaviour of Zn. The primary requirement is the elastic contribution, while the presence of magnetic disorder increases the critical concentrations for the onset of GB weakening. While Zn segregation is more favourable in bcc compared to fcc GB, larger impact of Zn coverage on GB weakening is observed for fcc. For both structures, the rapid decrease in surface defect state energies is identified as the driving force behind GB weakening. These surface defect states stabilize at lower Zn concentrations than GB defect states

ab initio insights into hydrogen UPTAKE AND EVOLUTION ON electrified solid/liquid interfaces

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Construction and analysis of surface phase diagrams to describe segregation and dissolution behavior of Al and Ca in Mg alloys

Segregation and dissolution behavior of Mg alloyed with Ca and Al are studied by performing density functional theory calculations considering an extensive set of surface structures and compositions. Combining ab initio surface science approaches with cluster expansion for ordered surface structures we construct surface phase diagrams for these alloys. We utilize these diagrams to study segregation phenomena and chemical trends for surfaces in contact with a dry environment or with an aqueous electrolyte. We show that the presence of water dramatically impacts the stability and chemical composition of the considered metallic surfaces. We furthermore find that the two alloying elements behave qualitatively different: whereas Ca strongly segregates to the surface and becomes dissolved upon exposure of the surface to water, Al shows an anti-segregation behavior, i.e., it remains in Mg bulk. These findings provide an explanation for the experimentally observed increase/decrease in corrosion rates when alloying Mg with Al/Ca.Comment: 12 pages, 9 figures, submitted to Phys. Rev. Material

selenium, selenoproteins, ADHD, depression, COVID-19, oxidative stress

In the pharmaceutical industry, more and more nutritional supplements are entering the market, the composition of which contains the trace element selenium, which has scientifically proven benefits for the human body.It is important for the proper implementation of human processes as well as for the maintenance of human systems. It has been proven that with an insufficient intake of selenium, the development of chronic degenerative diseases is possible. The trace element is known for its protection against oxidative stress in the human body, thanks to selenoproteins that break down hydrogen peroxide.Over 5.9% of the world's population suffers from Attention Deficit Hyperactivity Disorder (ADHD), which is characterized by inattention, impulsivity, and hyperactivity. Millions of people suffer from depression or have experienced it at some point in their lives. It is a mood disorder characterized by feelings of inadequacy, despondency, decreased activity, pessimism, and sadness.The COVID-19 pandemic has affected millions of people worldwide and resulted in hundreds of thousands of deaths. Currently, much research is focused on supportive nutritional therapies that can mitigate the susceptibility as well as the long-term complications of COVID-19. Selenium plays a key role in strengthening immunity, preventing viral infections, and supporting therapy in critical illnesses. In addition, its deficiency can affect the severity of the disease.The conditions listed above can be influenced by selenium, thanks to selenoproteins and their influence on oxidative stress

Analysis of Staphylococcus aureus Carriage Among Students at Varna Medical University

Introduction: Staphylococcus aureus is one of the most common causes of nosocomial infections. The main sources of transmission are hospital staff and contaminated hands.Aim: The current study presents data on nasal colonization among medical students undergoing training in high-risk hospital departments.Materials and Methods: We analyzed 253 nasal and 241 throat secretion samples from medical students who opted to be examined in the Laboratory of Microbiology at St. Marina University Hospital in Varna during the period 2021–2023. The samples were cultured on blood agar, and Staphylococcus aureus was identified using standard biochemical tests. Statistical analysis was performed using R Project software (version 4.0.4/2021-02-15).Results: Only 15.8% of nasal secretion samples tested positive for Staphylococcus aureus. Positive throat samples were almost negligible, accounting for only 1.2%. The proportion of positive women was higher, but the difference was not statistically significant (17.3% vs. 14% of men; χ² = 0.5 and p-value = 0.5). No statistically significant difference was observed in the number of positive samples across different age groups.Conclusion: Despite the low carriage rate observed, screening for nasal colonization can help reduce the risk of nosocomial transmission

The Role Of Artificial Intelligence In Drug Design

Artificial intelligence (AI) aims to simulate human thought and actions. It is an effective tool for various functions, including problem-solving and data classification.In recent years, AI has found numerous applications in the pharmaceutical sector. It is utilized in drug design, optimization of the manufacturing process, adherence to correct drug intake, prediction of treatment outcomes, processing of biomedical and clinical data, analysis of gene expression patterns, and detection of pandemic outbreaks. In modern drug design, AI plays a crucial role in creating molecular libraries, identifying new drug candidates with optimal properties, and predicting the biological functions of drugs with a protein structure.This article aims to present opportunities for optimizing the drug design process through the use of AI.To achieve this goal, a literature review method was used. Articles reviewed were selected from PubMed, Scopus, and Google Scholar databases.AI enables a more systematic search model and allows for the estimation of its parameters. The application of AI in drug design provides opportunities for process optimization, reducing the use of toxic reagents in synthesis. Additionally, AI can address key challenges in traditional drug design methods, such as low success rates, limited target options, poor transition from preclinical to clinical trials, lengthy processes, and high costs

On the origin of univalent Mg+^+ ions in solution and their role in anomalous anodic hydrogen evolution

Aqueous metal corrosion is a major economic concern in modern society. A phenomenon that has puzzled generations of scientists in this field is the so-called anomalous hydrogen evolution: the violent dissolution of magnesium under electron-rich (anodic) conditions, accompanied by strong hydrogen evolution, and a key mechanism hampering Mg technology. Experimental studies have indicated the presence of univalent Mg$^+$ in solution, but these findings have been largely ignored because they defy our common chemical understanding and evaded direct experimental observation. Using recent advances in the \emph{ab initio} description of solid-liquid electrochemical interfaces under controlled potential conditions, we described the full reaction path of Mg atom dissolution from a kinked Mg surface under anodic conditions. Our study reveals the formation of a solvated [Mg$^{2+}$(OH)$^-$]$^+$ ion complex, challenging the conventional assumption of Mg$^{2+}$ ion. This insight provides an intuitive explanation for the postulated presence of (coulombically) univalent Mg$^+$ ions and the absence of protective oxide/hydroxide layers normally formed under anodic/oxidizing conditions. The discovery of this unexpected and unconventional reaction mechanism is crucial for identifying new strategies for corrosion prevention and can be transferred to other metals

Chemical and structural characterization of the native oxide scale on a Mg-based alloy

In this study, the structure and composition of the native oxide forming on the basal plane (0001) of Mg-2Al-0.1Ca is investigated by a correlative approach, combining scanning transmission electron microscopy (STEM) and atom probe tomography (APT). Atom probe specimens were prepared conventionally in a Ga focused ion beam (FIB) as well as a Xe plasma FIB in a cryogenic setup and subsequently cleaned in the atom probe to remove surface contamination before oxidation. While thermal energy input from the laser and longer atmospheric exposure time increased the measured hydrogen content in the specimen's apex region, cryo preparation revealed, that the hydrogen uptake in magnesium is independent of the employment of conventional or cryogenic FIB preparation. TEM measurements demonstrated the growth of a (111) MgO oxide layer with 3-4 nm thickness on the basal (0001) plane of the Mg atom probe specimen. APT data further revealed the formation of an aluminum-rich region between bulk Mg and the native oxide. The aluminum enrichment of up to ~20 at.% at the interface is consistent with an inward growth of the oxide scale

SGLT2-Inhibition in Patients With Alport Syndrome

Introduction: Large-scale trials showed positive outcomes of sodium-glucose cotransporter-2 inhibitors (SGLT2i) in adults with chronic kidney disease (CKD). Whether the use of SGLT2i is safe and effective in patients with the common hereditary CKD Alport syndrome (AS) has not yet been investigated specifically in larger cohorts. Methods: This observational, multicenter, international study (NCT02378805) assessed 112 patients with AS after start of SGLT2i. The study's primary end point was change of albuminuria in albumin/g creatinine from the start of therapy. Results: Compared to randomized trials investigating the effect of SGLT2i in CKD, the adult patients in this study were younger (aged 38 ± 14 years) and had a better estimated glomerular filtration rate (eGFR, 63 ± 35 ml/min per 1.73 m2; n = 98). Maximum follow-up was 32 months. Compared to baseline, at the first 3 follow-up visits (months 1 to 3, 4 to 8, and 9 to 15) after initiation of SGLT2i therapy, a significant reduction of albuminuria in mg albumin/g creatinine (>30%) was observed. Mean loss of eGFR was 9 ± 12 ml/min per 1.73 m2 almost 1 year after initiation of SGLT2i therapy (n = 35). At a total of 71 patient-years at risk, 0.24 adverse events (AEs) per patient-year on SGLT2i were reported. Conclusion: This study indicates that, additive to renin-angiotensin system (RAS)-inhibition (RASi), SGLT2i have the potential to reduce the amount of albuminuria in patients with AS. Future studies are needed to investigate the long-term effects of SGLT2i on CKD progression in patients with AS to assess whether the observed reduction in albuminuria translates to a delay in kidney failure (KF)

SGLT2-Inhibition in patients with Alport syndrome

Introduction Large-scale trials showed positive outcomes of sodium–glucose cotransporter-2 inhibitors (SGLT2i) in adults with chronic kidney disease (CKD). Whether the use of SGLT2i is safe and effective in patients with the common hereditary CKD Alport syndrome has not yet been investigated specifically in larger cohorts. Methods This observational, multi-center, international study (NCT02378805) assessed 112 patients with Alport syndrome after start of SGLT2i. The study’s primary endpoint was change of albuminuria in albumin/gram creatinine from start of therapy. Results Compared to randomized trials investigating the effect of SGLT2i in CKD, the adult patients in this study were younger (38±14 years) and had a better estimated glomerular filtration rate, eGFR, (63±35 ml/min/1.73m2; n=98). Maximum follow up was 32 months. Compared to baseline, at the first three follow-up visits (months 1 to 3, 4 to 8 and 9 to 15) after initiation of SGLT2i-therapy, a significant reduction of albuminuria in milligrams albumin/gram creatinine (>30%) was observed. Mean loss of eGFR was 9±12 ml/min/1.73 m2 almost one year after initiation of SGLT2i-therapy (n=35). At a total of 71 patient-years at risk, 0.24 adverse events per patient year on SGLT2i were reported. Conclusion This study indicates that, additive to RAS-inhibition, SGLT2i have the potential to reduce the amount of albuminuria in patients with Alport syndrome. Future studies are needed to investigate the long-term effects of SGLT2i on CKD progression in patients with Alport syndrome to assess whether the observed reduction in albuminuria translates to a delay in kidney failure