Elastic-plastic finite element analysis of cracked solids Progress report

Elastic-plastic finite element analysis of cracked solid

The proteolytic landscape of cells exposed to non-lethal stresses is shaped by executioner caspases.

Cells are in constant adaptation to environmental changes to insure their proper functioning. When exposed to stresses, cells activate specific pathways to elicit adaptive modifications. Those changes can be mediated by selective modulation of gene and protein expression as well as by post-translational modifications, such as phosphorylation and proteolytic processing. Protein cleavage, as a controlled and limited post-translational modification, is involved in diverse physiological processes such as the maintenance of protein homeostasis, activation of repair pathways, apoptosis and the regulation of proliferation. Here we assessed by quantitative proteomics the proteolytic landscape in two cell lines subjected to low cisplatin concentrations used as a mild non-lethal stress paradigm. This landscape was compared to the one obtained in the same cells stimulated with cisplatin concentrations inducing apoptosis. These analyses were performed in wild-type cells and in cells lacking the two main executioner caspases: caspase-3 and caspase-7. Ninety-two proteins were found to be cleaved at one or a few sites (discrete cleavage) in low stress conditions compared to four hundred and fifty-three in apoptotic cells. Many of the cleaved proteins in stressed cells were also found to be cleaved in apoptotic conditions. As expected, ~90% of the cleavage events were dependent on caspase-3/caspase-7 in apoptotic cells. Strikingly, upon exposure to non-lethal stresses, no discrete cleavage was detected in cells lacking caspase-3 and caspase-7. This indicates that the proteolytic landscape in stressed viable cells fully depends on the activity of executioner caspases. These results suggest that the so-called executioner caspases fulfill important stress adaptive responses distinct from their role in apoptosis. Mass spectrometry data are available via ProteomeXchange with identifier PXD023488

N-glycans of human amniotic fluid transferrin stimulate progesterone production in human first trimester trophoblast cells in vitro

Aims: During pregnancy, the placenta produces a variety of steroid hormones and proteins. Several of these substances have been shown to exert immunomodulatory effects. Progesterone is thought to mediate some of these effects by regulating uterine responsiveness. The aim of this study was to clarify the effect of amniotic fluid transferrin and its N-glycans on the release of progesterone by first trimester trophoblast cells in vitro. Methods: Cytotrophoblast cells were prepared from human first trimester placentae by trypsin-DNAse dispersion of villous tissue followed by a percoll gradient centrifugation and depletion of CD45 positive cells by magnetic cell sorting. Trophoblasts were incubated with varying concentrations (50-300 mug/ml) of transferrin from human amniotic fluid and serum as well as with N-glycans obtained from amniotic fluid transferrin. Culture supernatants were assayed for progesterone by enzyme-immunometric methods. Results: The release of progesterone increased in amniotic fluid transferrin- and N-glycan-treated trophoblast cell cultures compared to untreated trophoblast cells. There was no stimulating effect of serum transferrin on the progesterone production of trophoblast cells. Conclusions: The results suggest that amnion-transferrin and especially its N-glycans modulate the endocrine function of trophoblasts in culture by up regulating progesterone secretion

Atresia of ovarian follicles in fishes, and implications and uses in aquaculture and fisheries

Atresia of ovarian follicles, that is the degenerative process of germ cells and their associated somatic cells, is a complex process involving apoptosis, autophagy and heterophagy. Follicular atresia is a normal component of fish oogenesis and it is observed throughout the ovarian cycle, although it is more frequent in regressing ovaries during the postspawning period. An increased occurrence of follicular atresia above physiological rates reduces fish fecundity and even causes reproductive failure in both wild and captive-reared fish stocks, and hence, this phenomenon has a wide range of implications in applied sciences such as fisheries and aquaculture. The present article reviews the available literature on both basic and applied traits of oocyte loss by atresia, including its morpho-physiological aspects and factors that cause a supraphysiological increase of follicular atresia. Finally, the review presents the use of early follicular atresia identification in the selection process of induced spawning in aquaculture and the implications of follicular atresia in fisheries management

An Economic Study of the Effect of Android Platform Fragmentation on Security Updates

Vendors in the Android ecosystem typically customize their devices by modifying Android Open Source Project (AOSP) code, adding in-house developed proprietary software, and pre-installing third-party applications. However, research has documented how various security problems are associated with this customization process. We develop a model of the Android ecosystem utilizing the concepts of game theory and product differentiation to capture the competition involving two vendors customizing the AOSP platform. We show how the vendors are incentivized to differentiate their products from AOSP and from each other, and how prices are shaped through this differentiation process. We also consider two types of consumers: security-conscious consumers who understand and care about security, and na\"ive consumers who lack the ability to correctly evaluate security properties of vendor-supplied Android products or simply ignore security. It is evident that vendors shirk on security investments in the latter case. Regulators such as the U.S. Federal Trade Commission have sanctioned Android vendors for underinvestment in security, but the exact effects of these sanctions are difficult to disentangle with empirical data. Here, we model the impact of a regulator-imposed fine that incentivizes vendors to match a minimum security standard. Interestingly, we show how product prices will decrease for the same cost of customization in the presence of a fine, or a higher level of regulator-imposed minimum security.Comment: 22nd International Conference on Financial Cryptography and Data Security (FC 2018

Hormonal manipulations for the enhancement of sperm production in cultured fish and evaluation of sperm quality

[EN] This article reviews the use of hormonal treatments to enhance sperm production in aquaculture fish and the methods available for evaluating sperm quality. The different types of testis development are examined and a brief review is presented of the endocrine regulation of spermatogenesis in fishes, including the increasing evidence of the existence of spermatozoa subpopulations. Hormonal manipulations are employed to induce spermatogenesis in species such as the freshwater eels, to synchronize maximal sperm volume to ovulation for in vitro fertilization and to enhance sperm production in species with poor spermiation. The hormones that are employed include gonadotropins (GtHs) of piscine or mammalian origin, and gonadotropin-releasing hormone agonists (GnRHa) administered by injections or controlled-release delivery systems, with or without dopaminergic inhibitors. Pheromones in the culture water and hormones added to the sperm in vitro have also been employed to enhance spermiation and sperm quality, respectively, in some fishes. Hormonal therapies usually do not affect sperm quality parameters, except in cases where fish fail to spermiate naturally or produce very small volumes of high-density sperm. Different parameters have been used to evaluate fish sperm quality, including sperm volume and density, spermatozoa motility and morphometry, and seminal plasma composition. The development of Computer-Assisted Sperm Analysis (CASA) systems made possible the estimation of a higher number of sperm motion parameters using an objective, sensitive and accurate technique. The development of Assisted Sperm Morphology Analysis (ASMA) software has introduced a new approach for sperm evaluation studies, demonstrating changes in the spermatozoa related to reproductive season, hormonal treatments or the cryopreservation processes, and how these may be related to changes in sperm motility and fertilization capacity. The article concludes with a few practical protocols for the enhancement of sperm production in aquaculture species.We would like to thank the COST Action FA1205 (AQUAGAMETE) titled “Assessing and improving the quality of aquatic animal gametes to enhance aquatic resources - The need to harmonize and standardize evolving methodologies, and improve transfer from academia to industry” for initiating the production of this special issue and funding partially this article. JFA has been partly funded by the Spanish Ministry of Economy and Competitiveness (REPRO-TEMP; AGL2013-41646-R) and the European Training Network IMPRESS (Marie SklodowskaCurie Actions; Grant agreement n°: 642893). ND has been funded partly by the INIA-FEDER project RTA2011-00050, and CCM and ND have been supported also by the EU project DIVERSIFY (7FP-KBBE-2013-GA 602131).Mylonas, CC.; Duncan, NJ.; Asturiano Nemesio, JF. (2017). Hormonal manipulations for the enhancement of sperm production in cultured fish and evaluation of sperm quality. Aquaculture. 472:21-44. https://doi.org/10.1016/j.aquaculture.2016.04.021S214447

Humanities in Predoctoral Dental Education: A Scoping Review

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153732/1/jddjde019126.pd