Restoring boundary conditions in the solidification of pure metals

The scope of the paper is an algorithm reconstructing the boundary conditions (heat flux and heat transfer coefficient) in the solidification of pure metals on the grounds of temperature measurements. For the verification of the algorithm experimental data derived in the course of the solidification of aluminum were used. An example of the application of the algorithm for designating the cooling conditions in continuous casting is provided, when the values of temperature at selected points on the boundary of the casting are known.     

Quantitative histological and ultrastructural features of opercula of normally erupting human teeth

Tooth eruption across the mucosa in humans has been studied rarely, although there are disturbances of eruption that are attributed specifically to failure of the supraosseous eruptive migration. The aim of this study was to analyze the soft tissues covering normally erupting teeth so as to get an insight into the supraosseous phase of tooth eruption and to provide the basis for comparison with cases of eruption disturbances. Six opercula covering normally erupting permanent molars (primary opercula) and six of succedaneous teeth (secondary opercula) were surgically removed from 10 patients aged 7.5-17.5 years. Specimens were examined light and electron microscopically and analyzed morphometrically. All opercula contained strands and islands of odontogenic epithelium, prominent numbers of high endothelial venules, nerves, and mast cells. Nerves comprised normally structured, 1.5-3.5 microm thick myelinated (Adelta) and thinner unmyelinated (C) fibers. In primary opercula, the proportions of blood vessels and nerves were three- and sevenfold higher than the respective values for the secondary opercula. Furthermore, primary opercula contained multinucleated, fibroblast-like giant cells that were not observed in secondary opercula. As all teeth under investigation were erupting normally, neither the presence of the giant cells nor the atypical proportions of blood vessels and nerves appeared to be decisive in the eruption process. These conspicuous tissue components of opercula seem merely to accompany the eruptive tooth movement.     

The Role of Strigolactones in Nutrient-Stress Responses in Plants

Strigolactones (SLs) are a new group of plant hormones, which have been intensively investigated during the last few years. The wide spectrum of SLs actions, including the regulation of shoot/root architecture, and the stimulation of the interactions between roots and fungi or bacteria, as well as the stimulation of germination of parasitic plants, indicates that this group of hormones may play an important role in the mechanisms that control soil exploration, and the root-mediated uptake of nutrients. Current studies have shown that SLs might be factors that have an influence on the plant response to a deficiency of macronutrients. Experimental data from the last four years have confirmed that the biosynthesis and exudation of SLs are increased under phosphorus and nitrogen deficiency. All these data suggest that SLs may regulate the complex response to nutrient stress, which include not only the modification of the plant developmental process, but also the cooperation with other organisms in order to minimize the effects of threats. In this paper the results of studies that indicate that SLs play an important role in the response to nutrient stress are reviewed and the consequences of the higher biosynthesis and exudation of SLs in response to phosphorus and nitrogen deficiency are discussed.     

SARS-CoV-2 Viral Entry Proteins in Hyperandrogenemic Female Mice: Implications for Women with PCOS and COVID-19

SARS-CoV-2, the causative agent of COVID-19, infects host cells using the angiotensin I converting enzyme 2 (ACE2) as its receptor after priming by host proteases, including TMPRSS2. COVID-19 affects multiple organ systems, and male patients suffer increased severity and mortality. Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in reproductive-age women and is characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovarian morphology. PCOS is associated with obesity and cardiometabolic comorbidities, both being risk factors associated with severe COVID-19 pathology. We hypothesize that elevated androgens in PCOS regulate SARS-CoV-2 entry proteins in multiple tissues increasing the risk for this population. Female mice were treated with dihydrotestosterone (DHT) for 90 days. Body composition was measured by EchoMRI. Fasting glucose was determined by an enzymatic method. mRNA and protein levels of ACE2, Tmprss2, Cathepsin L, Furin, Tmprss4, and Adam17 were quantified by RT-qPCR, Western-blot, or ELISA in tissues, serum, and urine. DHT treatment increased body weight, fat and lean mass, and fasting glucose. Ace2 mRNA was upregulated in the lung, cecum, heart, and kidney, while downregulated in the brain by DHT. ACE2 protein was upregulated by DHT in the small intestine, heart, and kidney. The SARS-CoV-2 priming proteases Tmprss2, Cathepsin L, and Furin mRNA were upregulated by DHT in the kidney. ACE2 sheddase Adam17 mRNA was upregulated by DHT in the kidney, which corresponded with increased urinary ACE2 in DHT treated mice. Our results highlight the potential for increased cardiac, renal, and gastrointestinal dysfunction in PCOS women with COVID-19.     

Prediction of the thermal conductivity anisotropy of Si nanofilms. Results of several numerical methods

The purpose of this work is to predict the in-plane and cross-plane thermal properties of crystalline silicon films. Several thicknesses from 20 nm to 6 μm and mean temperatures between 20 and 500 K have been investigated. Heat transport properties in silicon films have been studied through three different techniques: a semi-analytical method based upon the Kinetic Theory, a deterministic solution of the Boltzmann Transfer Equation (BTE) through the Discrete Ordinate Method and a statistical handling of the BTE by means of Monte Carlo Method. Each technique requires a model for the bulk material dispersion curves and the collision times of the different scattering processes. The three techniques have been validated through their correct prediction of silicon bulk thermal conductivity. Comparisons with in-plane thermal conductivity calculations and measurements have been also discussed. Thus, the cross-plane thermal conduction properties have been predicted. The expected temperature and thickness variations of the thermal conduction properties have been observed: the cross-plane thermal conduction appears to be less efficient than the in-plane thermal conduction, which proves that a significant anisotropy exists.     

Pathogens, personality, and culture: Disease prevalence predicts worldwide variability in sociosexuality, extraversion, and openness to experience.

Previous research has documented cross-cultural differences in personality traits, but the origins of those differences remain unknown. The authors investigate the possibility that these cultural differences can be traced, in part, to regional differences in the prevalence in infectious diseases. Three specific hypotheses are deduced, predicting negative relationships between disease prevalence and (a) unrestricted sociosexuality, (b) extraversion, and (c) openness to experience. These hypotheses were tested empirically with methods that employed epidemiological atlases in conjunction with personality data collected from individuals in dozens of countries worldwide. Results were consistent with all three hypotheses: In regions that have historically suffered from high levels of infectious diseases, people report lower mean levels of sociosexuality, extraversion, and openness. Alternative explanations are addressed, and possible underlying mechanisms are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)