Crystal and electronic structure of PbTe/CdTe nanostructures

In this article, the authors reported a theoretical study of structural and electronic properties of PbTe inclusions in CdTe matrix as well as CdTe nano-clusters in PbTe matrix. The structural properties are studied by ab initio methods. A tight-binding model is constructed to calculate the electron density of states (DOS) of the systems. In contrast to the ab initio methods, the latter allows studying nanostructures with diameters comparable to the real ones. The calculations show that both kinds of inclusions lead to changes of the DOS of the carriers near the Fermi level, which may affect optical, electrical and thermoelectric properties of the material. These changes depend on the size, shape, and concentration of inclusions

Solaris photometric survey: Search for circumbinary companions using eclipse timing variations

Eclipse timing variations (ETV) have been a successful tool for detecting circumbinary companions to eclipsing binaries (EB). While TESS and Kepler have been prolific for ETV searches, they sometimes can be limited by time and sky coverage which can be addressed by specialised ground-based ETV surveys. We present the initial results from the Solaris photometric survey which uses four 0.5m robotic telescopes in the southern hemisphere to look for circumbinary companions. We present the method of light curve extraction, detrending, and EB modelling using the observations from the Solaris network. Using these light curves we extract precise eclipse timing for 7 EB and look for companions using a Lomb-Scargle periodogram search. We find two possible periodic signals for the target GSC 08814-01026. With the system having strong activity, we check for the feasibility of orbital solutions at these two periods. We find that the 245 +/- 1 d period is due to an M-dwarf mass companion. This makes GSC 08814-01026 a candidate compact hierarchical triple system. The other periodic signal at 146 +/- 1 d is an artefact of stellar activity.Comment: 14 pages, 9 figures, Accepted for publication in MNRAS. This is a pre-copyedited, author-produced PDF of an article accepted for publication in MNRAS following peer revie

Cation exchange HPLC analysis of desmosines in elastin hydrolysates

Desmosine crosslinks are responsible for the elastic properties of connective tissues in lungs and cardiovascular system and are often compromised in disease states. We developed a new, fast, and simple cation exchange HPLC assay for the analysis of desmosine and isodesmosine in animal elastin. The method was validated by determining linearity, accuracy, precision, and desmosines stability and was applied to measure levels of desmosines in porcine and murine organs. The detection and quantification limits were 2 and 4 pmol, respectively. The run-time was 8 min. Our cation exchange column does not separate desmosine and isodesmosine, but their level can be quantified from absorbance at different wavelengths. Using this assay, we found that desmosines levels were significantly lower in elastin isolated from various organs of immunodeficient severe combined immunodeficiency mice compared with wild-type animals. We also found that desmosines levels were lower in lung elastin isolated from hyperhomocysteinemic Pcft−/− mice deficient in intestinal folate transport compared with wild-type Pcft+/+ animals

Scaling slowly rotating asteroids with stellar occultations

Context. As evidenced by recent survey results, the majority of asteroids are slow rotators (spin periods longer than 12 h), but lack spin and shape models because of selection bias. This bias is skewing our overall understanding of the spins, shapes, and sizes of asteroids, as well as of their other properties. Also, diameter determinations for large (>60 km) and medium-sized asteroids (between 30 and 60 km) often vary by over 30% for multiple reasons. Aims. Our long-term project is focused on a few tens of slow rotators with periods of up to 60 h. We aim to obtain their full light curves and reconstruct their spins and shapes. We also precisely scale the models, typically with an accuracy of a few percent. Methods. We used wide sets of dense light curves for spin and shape reconstructions via light-curve inversion. Precisely scaling them with thermal data was not possible here because of poor infrared datasets: large bodies tend to saturate in WISE mission detectors. Therefore, we recently also launched a special campaign among stellar occultation observers, both in order to scale these models and to verify the shape solutions, often allowing us to break the mirror pole ambiguity. Results. The presented scheme resulted in shape models for 16 slow rotators, most of them for the first time. Fitting them to chords from stellar occultation timings resolved previous inconsistencies in size determinations. For around half of the targets, this fitting also allowed us to identify a clearly preferred pole solution from the pair of two mirror pole solutions, thus removing the ambiguity inherent to light-curve inversion. We also address the influence of the uncertainty of the shape models on the derived diameters. Conclusions. Overall, our project has already provided reliable models for around 50 slow rotators. Such well-determined and scaled asteroid shapes will, for example, constitute a solid basis for precise density determinations when coupled with mass information. Spin and shape models in general continue to fill the gaps caused by various biases

The problem of alcohol addiction among students

Celem pracy było omówienie problemu uzależnienia od alkoholu wśród studentów. Praca ma za zadanie wskazać jak duży problem uzależnienia alkoholem występuje w Polsce jak i na świecie. W pracy ukazano jak dużego obszaru dotyka problem alkoholu oraz jak duży wpływ ma on na dalsze życie osób, w szczególności studentów. Alkoholizm wśród osób studiujących powoduje wiele problemów. Przyczyny alkoholizmu wśród studentów wynikają z wielu czynników oraz przyczyn. Studenci podczas studiowania są w większym stopniu podatni na spożywanie alkoholu, co wiąże się z większym ryzykiem popadnięcia w nałóg. Praca zgłębia profilaktykę w zakresie przeciwdziałania alkoholizmowi. Wnioski wskazują na wieloaspektowe przyczyny uzależnienia od alkoholu i równocześnie na duży zakres skutków tego uzależnienia.The aim of the study was to discuss the problem of alcohol dependence among students. The aim of the paper is to show how big the problem of alcohol addiction is in Poland and in the world. The paper shows how large area is affected by the problem of alcohol and how it affects the further life of people, particularly students. Alcoholism among students causes many problems. The causes of alcoholism among students are due to many factors and causes. Students are more likely to consume alcohol while studying, which is associated with higher risk of falling into addiction. The paper explores the prevention of alcoholism. The findings indicate the multifaceted causes of alcohol addiction and at the same time the large range of consequences of alcohol addiction

The power of society to fight the crisis

Celem niniejszej pracy było omówienie zdolności społeczeństwa w walce z kryzysem. Głównym aspektem było omówienie motywacji społeczeństwa polskiego wobec uchodźców z Ukrainy. Głównym przedmiotem pracy jest problem badawczy dotyczący samoorganizacji Polaków wobec kryzysu uchodźczego wywiązanego w wojnie na Ukrainie. Zamierzeniem pracy jest ustalenie jakie reakcje towarzyszyły obywatelom podczas przyjęcia uchodźców z Ukrainy oraz motywacji społeczeństwa polskiego, które podjęło się pomocy uchodźcom. Wykazano jakie formy wsparcia były dostępne dla imigrantów oraz co było inicjacją ruchu społeczeństwa w celu pomocy. Niniejsza praca zgłębia tematy związane z przyjmowaniem uchodźców do Polski oraz skupia się na analizie rozwoju konfliktu zbrojnego na Ukrainie. Interpretacja pozyskanych danych może mieć wpływ na przyszłe działania wobec przyszłych sytuacji kryzysowych. Zrozumienie motywacji obywateli może pozytywnie wpłynąć na przyszłe zachowanie rządu i społeczeństwa wobec przyjmowania kolejnych uchodźców.The purpose of this paper was to discuss society's ability to deal with the crisis. The main aspect was to discuss the motivation of Polish society towards refugees from Ukraine. The main subject of the work is a research problem concerning the self-organization of Poles in the face of the refugee crisis emanating from the war in Ukraine. The intention of the work is to determine what reactions accompanied the citizens during the reception of refugees from Ukraine and the motivation of Polish society, which undertook to help refugees. It is shown what forms of support were available to the immigrants and what was the initiation of the society's movement to help. This thesis explores topics related to the reception of refugees to Poland and focuses on the analysis of the development of the armed conflict in Ukraine. Interpretation of the data obtained may have implications for future actions in the face of future emergencies. Understanding the motivations of citizens can positively influence the future behavior of the government and society towards accepting more refugees

N-Homocysteinylation impairs collagen cross-linking in cystathionine β-synthase-deficient mice: a novel mechanism of connective tissue abnormalities

Cystathionine β-synthase (CBS) deficiency, a genetic disorder in homocysteine (Hcy) metabolism in humans, elevates plasma Hcy-thiolactone and leads to connective tissue abnormalities affecting cardiovascular and skeletal systems. However, the underlying mechanism of these abnormalities is not understood. Hcy-thiolactone has the ability to form isopeptide bonds with protein lysine residues, which generates N-homocysteinylated protein. Because lysine residues are involved in collagen crosslinking, N-homocysteinylation of these lysines should impair crosslinking. Using a Tg-I278T Cbs -/- mouse model of hyperhomocysteinamia (HHcy) that recapitulates connective tissue abnormalities observed in CBS-deficient patients, we show that N-Hcy-collagen was elevated in bone, tail, and heart of Cbs -/- mice, while pyridinoline crosslinks were significantly reduced. Plasma deoxypyridinoline crosslink and crosslinked carboxyterminal telopeptide of type I collagen were also significantly reduced in Cbs -/- mice. Lysine oxidase activity and mRNA level were not reduced by the Cbs -/- genotype. We also show that collagen carries S-linked Hcy bound to the thiol of N-linked Hcy. In vitro experiments show that Hcy-thiolactone modifies lysine residues in collagen type I alpha-1 chain. Residue K160, located in the non-helical N-telopeptide region and involved in pyridinoline crosslink formation, was also N-homocysteinylated in vivo. Taken together, our findings show that N- homocysteinylation of collagen in Cbs -/- mice impairs its crosslinking. These findings explain at least in part connective tissue abnormalities observed in HHcy

COVID-19 and One-Carbon Metabolism

Dysregulation of one-carbon metabolism affects a wide range of biological processes and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Accumulating evidence suggests that one-carbon metabolism plays an important role in COVID-19. The symptoms of long COVID-19 are similar to those presented by subjects suffering from vitamin B12 deficiency (pernicious anemia). The metabolism of a cell infected by the SARS-CoV-2 virus is reshaped to fulfill the need for massive viral RNA synthesis, which requires de novo purine biosynthesis involving folate and one-carbon metabolism. Many aspects of host sulfur amino acid metabolism, particularly glutathione metabolism underlying antioxidant defenses, are also taken over by the SARS-CoV-2 virus. The purpose of this review is to summarize recent findings related to one-carbon metabolism and sulfur metabolites in COVID-19 and discuss how they inform strategies to combat the disease

Dysregulation of Epigenetic Mechanisms of Gene Expression in the Pathologies of Hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) exerts a wide range of biological effects and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Although mechanisms of HHcy toxicity are not fully uncovered, there has been a significant progress in their understanding. The picture emerging from the studies of homocysteine (Hcy) metabolism and pathophysiology is a complex one, as Hcy and its metabolites affect biomolecules and processes in a tissue- and sex-specific manner. Because of their connection to one carbon metabolism and editing mechanisms in protein biosynthesis, Hcy and its metabolites impair epigenetic control of gene expression mediated by DNA methylation, histone modifications, and non-coding RNA, which underlies the pathology of human disease. In this review we summarize the recent evidence showing that epigenetic dysregulation of gene expression, mediated by changes in DNA methylation and histone N-homocysteinylation, is a pathogenic consequence of HHcy in many human diseases. These findings provide new insights into the mechanisms of human disease induced by Hcy and its metabolites, and suggest therapeutic targets for the prevention and/or treatment