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This paper presents the advantage of rapid tooling and more specifically the Stratoconception process in order to realize a die casting mould. A test case of a die casting mould is presented. A complete procedure has been developed in order to improve the efficiency of the tooling especially thanks to improved cooling channels. This procedure includes not only the numerical simulations of the heat transfer and the thermomechanical behaviour of the tooling as a help to design but also the manufacturing of the tooling and experimental manipulations. [ABSTRACT FROM AUTHOR]

Cemented carbide based cutting tools remain widely used in machining processes for their wear resistance. Knowledge and modelling of wear processes are of prior importance to get models to predict and increase the cutting tool service life. The present paper deals with some results of a research work that study relationships between wear and temperature in the case of pin-on-disc tribological experiments. Topic of the paper is focussed on the estimation of the pin/disc contact temperature by coupling experimental measurements and computational methods. Friction experiments are conducted with WC-6Co pins against steel discs made of an AISI 1045 grade. Furthermore, WC-6Co pins are instrumented with two type-K thermocouples. A large sliding velocity range is considered in the study: from 100m/min up to 600m/min. The present paper is focussed on the 600m/min velocity. During these tribological tests, tangential forces and thermocouple temperatures are measured and monitored. From these values, the heat flux in the WC-6Co pin is estimated by two different ways. On one hand by considering the unidirectional Fourier law, on the other hand by estimating the heat partition coefficient [1] between the disc and the pin. The heat partition coefficient is determined from a physical approach based on the consideration of the mechanical power dissipated in the contact. In both cases, the heat transfer in the pin is then modelled by finite element methods. It is necessary to perform numerical analysis to estimate the pin/disc interface temperature because of the impossibility to measure it directly during friction tests. Results of experiments and of numerical simulations are compared. [ABSTRACT FROM AUTHOR]

Selenium is an essential trace element due to its incorporation into selenoproteins with important biological functions. However, at high doses it is toxic. Selenium toxicity is generally attributed to the induction of oxidative stress. However, it has become apparent that the mode of action of seleno-compounds varies, depending on its chemical form and speciation. Recent studies in various eukaryotic systems, in particular the model organism Saccharomyces cerevisiae, provide new insights on the cytotoxic mechanisms of selenomethionine and selenocysteine. This review first summarizes current knowledge on reactive oxygen species (ROS)-induced genotoxicity of inorganic selenium species. Then, we discuss recent advances on our understanding of the molecular mechanisms of selenocysteine and selenomethionine cytotoxicity. We present evidences indicating that both oxidative stress and ROS-independent mechanisms contribute to selenoamino acids cytotoxicity. These latter mechanisms include disruption of protein homeostasis by selenocysteine misincorporation in proteins and/or reaction of selenols with protein thiols.

Selenium is an essential trace element co-translationally incorporated into selenoproteins with important biological functions. Health benefits have long been associated with selenium supplementation. However, cytotoxicity is observed upon excessive selenium intake. The aim of this study is to investigate the metabolic pathways underlying the response to the selenium-containing amino acids selenomethionine and selenocysteine in a normal human breast epithelial cell model. We show that both selenomethionine and selenocystine inhibit the proliferation of non-cancerous MCF-10A cells in the same concentration range as cancerous MCF-7 and Hela cells, which results in apoptotic cell death. Selenocystine exposure in MCF-10A cells caused a severe depletion of free low molecular weight thiols, which might explain the observed upregulation of the expression of the oxidative stress pathway transcription factor NRF2. Both selenomethionine and selenocystine induced the expression of target genes of the unfolded protein response (GRP78, ATF4, CHOP). Using a redox-sensitive fluorescent probe targeted to the endoplasmic reticulum (ER), we show that both selenoamino acids shifted the ER redox balance towards an even more oxidizing environment. These results suggest that alteration of the redox state of the ER may disrupt protein folding and cause ER stress-induced apoptosis in MCF-10A cells exposed to selenoamino acids., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Female rabbits often exhibit reproductive tract disorders and accurate sonographic descriptions of the normal genital tract are lacking. The aims of our prospective, analytical, and reference interval study were to describe the ultrasonographic appearance of the genital tract of healthy female rabbits, provide reference values, and compare ultrasonographic findings with histopathological samples. Twenty-eight intact female rabbits presented for elective ovariohysterectomy were included. Ovaries, oviducts, uterine horns, cervixes, and vagina were imaged by ultrasound to assess their size, shape, location, margination, echogenicity, and echotexture. The genital tract of 12 rabbits was sent for histopathology. Genitals were visible in all rabbits using the linear probe. The ovaries were oval-shaped and hypoechoic with a variable pattern. The oviducts, uterine horns, and vagina appeared as tubular structures with a consistent distinct layering, and the cervix as two contiguous hypoechoic tubular structures with a variable layering. Incidental findings, including paraovarian cysts, mineralization foci, and luminal fluid were observed. The median values of the height of the left and right ovaries, oviducts, uterine horns, cervixes, and vagina were, respectively, equal to 3.52 3.37, 1.39, 1.39, 4.34, 4.36, 5.57, 5.15, and 2.40 mm. Significant correlations were observed among age, body condition score, and some of the measurements. Abnormalities of the reproductive tract were reported in 4 of 28 rabbits. This study supports the use of ultrasonography in the evaluation of the reproductive tract of healthy female rabbits and provides reference values for use in rabbits with genital disorders., (© 2023 American College of Veterinary Radiology.)

Objectives: The duodenal papilla (DP) is an anatomical structure located in the duodenal wall, a few centimetres from the pylorus. In cats, the pancreatic and bile ducts merge as they enter the DP, and this explains why cats are more likely than dogs to have concomitant digestive, pancreatic and hepatic infections. Ultrasonography of the DP has been previously established in dogs but not in cats. The purpose of our prospective study was to describe the ultrasound features of the DP in 30 adult clinically healthy cats., Methods: A full abdominal ultrasound was performed. Five measurements were recorded: the width and the height in a transverse section; the length and the height in a longitudinal section; and the thickness of the duodenal wall adoral to the DP in a longitudinal section. The subjective appearance (echogenicity and shape) of the DP was described., Results: The dimensions of the DP were a mean ± SD width of 3.13 ± 0.68 mm and height of 2.47 ± 0.63 mm in the transverse section, and length of 3.98 ± 1.27 mm and height of 2.44 ± 0.57 mm in the longitudinal section. The DP was homogeneous, subjectively isoechoic to fat and had a round and oval shape in the transverse and longitudinal sections, respectively. There was no correlation between the DP measurements and the weight, age or sex of the cats. The animals that were fed a mixed diet had a longer DP than those fed dry food., Conclusions and Relevance: This study provides reference values for the dimensions of the DP, as well as information on its ultrasonographic appearance in clinically healthy adult cats. We did not find any correlation between the age of the cats and the size of the papilla, but the age range was small and another study in older cats should be undertaken to address this more thoroughly.

In this work, a physical model based on the radiative transfer equation is presented to estimate the global solar irradiance on top of the Earth's atmosphere surface. A link is established among the radiative transfer through the atmosphere, the geographic coordinates of a city (longitude, latitude), time of day, and date of the year. The discrete spherical harmonics method is applied to solve the radiative transfer equation. The city of Dschang in Cameroon is taken as an example of application of the model. This city is located at latitude 5°44 ' N and longitude 10°04 ' E. It is assumed that the atmosphere of the city is inhomogeneous and composed of non-polarizing Haze L aerosol particles in gamma distribution, while the ground surface diffuses radiation isotropically. The predictions are compared under clear sky conditions to some existing models of irradiance such as the Bird model and Davies and Hay model for a homogeneous atmosphere. Results demonstrate that the present investigation matches well with the Bird and the Davies and Hay models and is valuable for ground solar irradiance estimation. The effects of the inhomogeneity of the atmosphere on total insolation are also studied, and our results indicate that the inhomogeneity of the atmosphere reduces local insolation. The present study shows that the radiative transfer model is an efficient technique for estimating global solar radiation at any level of the stratified atmosphere and under different atmospheric conditions.

Methylselenol (MeSeH) is a major cytotoxic metabolite of selenium, causing apoptosis in cancer cells through mechanisms that remain to be fully established. Previously, we demonstrated that, in Saccharomyces cerevisiae , MeSeH toxicity was mediated by its metabolization into selenomethionine by O-acetylhomoserine (OAH)-sulfhydrylase, an enzyme that is absent in higher eukaryotes. In this report, we used a mutant met17 yeast strain, devoid of OAH- sulfhydrylase activity, to identify alternative targets of MeSeH. Exposure to dimethyldiselenide (DMDSe), a direct precursor of MeSeH, caused an endoplasmic reticulum (ER) stress, as evidenced by increased expression of the ER chaperone Kar2p. Mutant strains (∆ ire1 and ∆ hac1 ) unable to activate the unfolded protein response were hypersensitive to MeSeH precursors but not to selenomethionine. In contrast, deletion of YAP1 or SKN7 , required to activate the oxidative stress response, did not affect cell growth in the presence of DMDSe. ER maturation of newly synthesized carboxypeptidase Y was impaired, indicating that MeSeH/DMDSe caused protein misfolding in the ER. Exposure to DMDSe resulted in induction of the expression of the ER oxidoreductase Ero1p with concomitant reduction of its regulatory disulfide bonds. These results suggest that MeSeH disturbs protein folding in the ER by generating a reductive stress in this compartment.

Methylselenol (MeSeH) has been suggested to be a critical metabolite for anticancer activity of selenium, although the mechanisms underlying its activity remain to be fully established. The aim of this study was to identify metabolic pathways of MeSeH in Saccharomyces cerevisiae to decipher the mechanism of its toxicity. We first investigated in vitro the formation of MeSeH from methylseleninic acid (MSeA) or dimethyldiselenide. Determination of the equilibrium and rate constants of the reactions between glutathione (GSH) and these MeSeH precursors indicates that in the conditions that prevail in vivo, GSH can reduce the major part of MSeA or dimethyldiselenide into MeSeH. MeSeH can also be enzymatically produced by glutathione reductase or thioredoxin/thioredoxin reductase. Studies on the toxicity of MeSeH precursors (MSeA, dimethyldiselenide or a mixture of MSeA and GSH) in S. cerevisiae revealed that cytotoxicity and selenomethionine content were severely reduced in a met17 mutant devoid of O-acetylhomoserine sulfhydrylase. This suggests conversion of MeSeH into selenomethionine by this enzyme. Protein aggregation was observed in wild-type but not in met17 cells. Altogether, our findings support the view that MeSeH is toxic in S. cerevisiae because it is metabolized into selenomethionine which, in turn, induces toxic protein aggregation.

The propagation of radiation in an absorbing-scattering soil with constant or spatial variation of the refractive index is investigated. The soil consists of a plane parallel with Fresnel reflection at the boundaries and is exposed at one boundary to a diffuse or collimated incident radiation. The discrete spherical harmonics method using Marshak boundary conditions is introduced to approximate the directional hemispherical reflectance and transmittance as well as the bidirectional reflectance. The effect in spatial variation of the refractive index on the reflectance and transmittance predictions is examined. A comparison of the directional transmittance and reflectance with the literature results demonstrates that the present method gives accurate results for optically thin and thick soil with a maximum relative error in all cases less than 1%. The bidirectional radiance for variable refractive index soils also shows excellent agreement as compared to the literature results. The results demonstrated that the anisotropic soil interfaces cause a significant decrease of energy reflected and transmitted as well as the bidirectional reflectance.

Selenomethionine, a dietary supplement with beneficial health effects, becomes toxic if taken in excess. To gain insight into the mechanisms of action of selenomethionine, we screened a collection of ≈5900 Saccharomyces cerevisiae mutants for sensitivity or resistance to growth-limiting amounts of the compound. Genes involved in protein degradation and synthesis were enriched in the obtained datasets, suggesting that selenomethionine causes a proteotoxic stress. We demonstrate that selenomethionine induces an accumulation of protein aggregates by a mechanism that requires de novo protein synthesis. Reduction of translation rates was accompanied by a decrease of protein aggregation and of selenomethionine toxicity. Protein aggregation was supressed in a ∆cys3 mutant unable to synthetize selenocysteine, suggesting that aggregation results from the metabolization of selenomethionine to selenocysteine followed by translational incorporation in the place of cysteine. In support of this mechanism, we were able to detect random substitutions of cysteinyl residues by selenocysteine in a reporter protein. Our results reveal a novel mechanism of toxicity that may have implications in higher eukaryotes.