Phase-field modeling and simulation of fracture in brittle materials with strongly anisotropic surface energy

Crack propagation in brittle materials with anisotropic surface energy is important in applications involving single crystals, extruded polymers, or geological and organic materials. Furthermore, when this anisotropy is strong, the phenomenology of crack propagation becomes very rich, with forbidden crack propagation directions or complex sawtooth crack patterns. This problem interrogates fundamental issues in fracture mechanics, including the principles behind the selection of crack direction. Here, we propose a variational phase-field model for strongly anisotropic fracture, which resorts to the extended Cahn-Hilliard framework proposed in the context of crystal growth. Previous phase-field models for anisotropic fracture were formulated in a framework only allowing for weak anisotropy. We implement numerically our higher-order phase-field model with smooth local maximum entropy approximants in a direct Galerkin method. The numerical results exhibit all the features of strongly anisotropic fracture and reproduce strikingly well recent experimental observations.Peer ReviewedPostprint (author’s final draft

A web-based system for tissue microarray data management

BACKGROUND: Tissue Microarray is a novel technique for analysing large amounts of immunohistochemically stained specimens. However, those large amounts make it difficult to design, prepare and analyze a tissue microarray, so that software support is almost inevitable. METHODS: We designed a tissue microarray data management system starting from specifications obtained by pathologists, and arranged for a preliminary validation in thyroid pathology. RESULTS: A web-based system has been developed, basing on open-source software and principles, that was well accepted by pathologists and allowed to carry out a study on 52 thyroid pathology cases. CONCLUSION: Though limited in functionalities, the developed system is effective and can be downloaded at the address

Phase-field modeling and simulation of fracture in brittle materials with strongly anisotropic surface energy

Crack propagation in brittle materials with anisotropic surface energy is important in applications involving single crystals, extruded polymers, or geological and organic materials. Furthermore, when this anisotropy is strong, the phenomenology of crack propagation becomes very rich, with forbidden crack propagation directions or complex sawtooth crack patterns. This problem interrogates fundamental issues in fracture mechanics, including the principles behind the selection of crack direction. Here, we propose a variational phase-field model for strongly anisotropic fracture, which resorts to the extended Cahn-Hilliard framework proposed in the context of crystal growth. Previous phase-field models for anisotropic fracture were formulated in a framework only allowing for weak anisotropy. We implement numerically our higher-order phase-field model with smooth local maximum entropy approximants in a direct Galerkin method. The numerical results exhibit all the features of strongly anisotropic fracture and reproduce strikingly well recent experimental observations. rack propagation in brittle materials with anisotropic surface energy is important in applications involving single crystals, extruded polymers, or geological and organic materials. Furthermore, when this anisotropy is strong, the phenomenology of crack propagation becomes very rich, with forbidden crack propagation directions or complex sawtooth crack patterns. This problem interrogates fundamental issues in fracture mechanics, including the principles behind the selection of crack direction. Here, we propose a variational phase-field model for strongly anisotropic fracture, which resorts to the extended Cahn-Hilliard framework proposed in the context of crystal growth. Previous phase-field models for anisotropic fracture were formulated in a framework only allowing for weak anisotropy. We implement numerically our higher-order phase-field model with smooth local maximum entropy approximants in a direct Galerkin method. The numerical results exhibit all the features of strongly anisotropic fracture and reproduce strikingly well recent experimental observations

Coal-tar dye-based coordination cages and helicates

A strategy to implement four members of the classic coal-tar dye family, Michler´s ketone, methylene blue, rhodamine B and crystal violet, into [Pd2L4] self-assemblies is introduced. Chromophores were incorporated into bis-monodentate ligands using piperazine linkers that allow to retain the auxochromic dialkyl amine functionalities required for intense colors deep in the visible spectrum. Upon palladium coordination, ligands with pyridine donors form lantern-shaped dinuclear cages while quinoline donors lead to strongly twisted [Pd2L4] helicates in solution. In one case, single crystal X-ray diffraction revealed rearrangement to a [Pd3L6] ring structure in the solid state. For nine examined derivatives, showing colors from yellow to deep violet, CD spectroscopy discloses different degrees of chiral induction by an enantiomerically pure guest. Ion mobility mass spectrometry allows to distinguish two binding modes. Self-assemblies based on this new ligand class promise application in chiroptical recognition, photo-redox catalysis and optical materials

The Ethics Of Cyberveillance In A Global Context

Whether one calls it “cyberveillance,” “cybermonitoring,” “cybersnooping,” or “cyberspying,” one thing is clear, the computer activities of employees are increasingly being monitored by their companies. Some reports suggest that up to 17% of the Fortune 1,000 companies now utilize some form of computer monitoring software and the predictions are that this figure will jump to 80% very soon. Such software allows an employer to monitor virtually every message sent, website visited and key stroked. Given the global reach of many of these large firms, there are at least two major concerns that need to be addressed. First, what are the ethical implications of this practice? Given that 12% of all firms report that they do not notify their employees of their monitoring activities, are employees being treated fairly? And second, in what ways are local customs, mores and values in various parts of the world being violated or ignored? Like it or not, we are awash in what various popular writers have termed “cyberveillance,” “cybermonitoring,” “cybersnooping,” or “cyberspying.” Simply put, employees’ use of the Internet and email today are increasingly being monitored by their companies. What seems to be missing in this rush to monitor are the ethical implications of doing so, which are significantly exacerbated in multinational firms. In order to understand how such actions are likely to be seen from a variety of multinational perspectives, we first developed a case involving a multinational company contemplating cybermonitoring and then we queried a group of international scholars, asking them to first approach managers in their region for reactions to the case, and then to provide a summary and synthesis of as to how such actions would be received in their respective parts of the world. Finally, we conclude by presenting a reasoned analysis regarding the general ethical questions involved.Before you read this analysis, we invite you to first read the case below and think about your own reactions. This is a hypothetical case involving composite information from the popular press involving a multinational bank. The bank is trying to decide if it should purchase and utilize monitoring software

A new pyranoxanthone from the stem bark of Calophyllum buxifolium

A new pyranoxanthone, buxixanthone (1), was isolated from the stem bark of Calophyllum buxifolium along with three other chemical constituents, ananixanthone (2), pyranojacareubin (3), and macluraxanthone (4). The structures of these compounds were confirmed through spectroscopic analysis, which included 1D and 2D NMR, GC/MS, and IR experiments

NK cell-derived IL-10 is critical for DC-NK cell dialogue at the maternal- fetal interface

DC-NK cell interactions are thought to influence the development of maternal tolerance and de novo angiogenesis during early gestation. However, it is unclear which mechanism ensures the cooperative dialogue between DC and NK cells at the feto-maternal interface. In this article, we show that uterine NK cells are the key source of IL-10 that is required to regulate DC phenotype and pregnancy success. Upon in vivo expansion of DC during early gestation, NK cells expressed increased levels of IL-10. Exogenous administration of IL-10 was sufficient to overcome early pregnancy failure in dams treated to achieve simultaneous DC expansion and NK cell depletion. Remarkably, DC expansion in IL-10−/− dams provoked pregnancy loss, which could be abrogated by the adoptive transfer of IL-10+/+ NK cells and not by IL-10−/− NK cells. Furthermore, the IL-10 expressing NK cells markedly enhanced angiogenic responses and placental development in DC expanded IL-10−/− dams. Thus, the capacity of NK cells to secrete IL-10 plays a unique role facilitating the DC- NK cell dialogue during the establishment of a healthy gestation

Prenatal transfer of gut bacteria in Rock pigeon

Vertebrates evolved in concert with bacteria and have developed essential mutualistic relationships. Gut bacteria are vital for the postnatal development of most organs and the immune and metabolic systems and may likewise play a role during prenatal development. Prenatal transfer of gut bacteria is shown in four mammalian species, including humans. For the 92% of the vertebrates that are oviparous, prenatal transfer is debated, but it has been demonstrated in domestic chicken. We hypothesize that also non-domestic birds can prenatally transmit gut bacteria. We investigated this in medium-sized Rock pigeon (Columba livia), ensuring neonates producing fair-sized first faeces. The first faeces of 21 neonate rock pigeons hatched in an incubator, contained a microbiome (bacterial community) the composition of which resembled the cloacal microbiome of females sampled from the same population (N = 5) as indicated by multiple shared phyla, orders, families, and genera. Neonates and females shared 16.1% of the total number of OTUs present (2881), and neonates shared 45.5% of their core microbiome with females. In contrast, the five females shared only 0.3% of the 1030 female OTUs present. These findings suggest that prenatal gut bacterial transfer may occur in birds. Our results support the hypothesis that gut bacteria may be important for prenatal development and present a heritability pathway of gut bacteria in vertebrates

Utjecaj prekurzora na hlapljive sastojke vina dobivenog fermentacijom soka papaje pomoću mješovite kulture kvasaca

The impact of the addition of fusel oil or amino acids on the volatile compounds in papaya wine fermented with a mixed culture of Saccharomyces cerevisiae var. bayanus R2 and Williopsis saturnus var. mrakii NCYC 2251 at a ratio of 1:1000 was studied. Fusel oil addition increased the fraction of alcohols and promoted the production of isoamyl octanoate, isoamyl decanoate and isobutyl decanoate, while decreased the fraction of ethyl acetate and 2-phenylethyl acetate. The addition of amino acids enhanced the formation of total volatile fatty acids, 2-phenylethanol and some ethyl esters. The papaya wine with added amino acids possessed more acidic and buttery notes than the control, while that with added fusel oil had an overall aroma profile comparable to that of the control. This study suggests that papaya juice fermentation with mixed yeasts in conjunction with the added fusel oil or selected amino acids may be another method of modulating the flavour of papaya wine.U ovom je radu ispitan utjecaj dodatka patočnog ulja ili aminokiselina na hlapljive sastojke vina dobivenog fermentacijom soka papaje pomoću mješovite kulture kvasaca Saccharomyces cerevisiae var. bayanus R2 i Williopsis saturnus var. mrakii NCYC 2251 u omjeru 1:1000. Dodatkom patočnog ulja povećan je udjel alkohola, te je poboljšana proizvodnja izoamilnog oktanoata, izoamilnog dekanoata i izobutilnog dekanoata, dok je smanjen udjel etilnog acetata i 2-feniletilnog acetata. Nastanak hlapljivih masnih kiselina, 2-feniletanola i nekih etilnih estera pospješen je dodatkom aminokiselina. U usporedbi s kontrolnim uzorkom, vino proizvedeno fermentacijom papaje uz dodatak aminokiselina imalo je izraženiju kiselu i putrastu notu, dok se aroma vina kojem je dodano patočno ulje nije razlikovala. Ovo je istraživanje pokazalo da se fermentacijom soka papaje pomoću mješovite kulture kvasaca uz dodatak patočnog ulja ili odabranih aminokiselina može promijeniti aroma vina

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London