A Drosophila Model for Clostridium difficile Toxin CDT Reveals Interactions with Multiple Effector Pathways.

Clostridium difficile infections (CDIs) cause severe and occasionally life-threatening diarrhea. Hyper-virulent strains produce CDT, a toxin that ADP-ribosylates actin monomers and inhibits actin polymerization. We created transgenic Drosophila lines expressing the catalytic subunit CDTa to investigate its interaction with host signaling pathways in vivo. When expressed in the midgut, CDTa reduces body weight and fecal output and compromises survival, suggesting severe impairment of digestive functions. At the cellular level, CDTa induces F-actin network collapse, elimination of the intestinal brush border, and disruption of intercellular junctions. We confirm toxin-dependent re-distribution of Rab11 to enterocytes' apical surface and observe suppression of CDTa phenotypes by a Dominant-Negative form of Rab11 or RNAi of the dedicated Rab11GEF Crag (DENND4). We also report that Calmodulin (Cam) is required to mediate CDTa activity. In parallel, chemical inhibition of the Cam/Calcineurin pathway by Cyclosporin A or FK506 also reduces CDTa phenotypes, potentially opening new avenues for treating CDIs

Fluid-Structure Interaction model for collapsing cavitation bubble near deformable solid boundaries

International audienceThe motivation behind this research lies in understanding the physical mechanism of cavitation erosion in compressible liquid flows, with applications in the field of aerospace, hydrodynamics, diesel injectors etc. As a consequence of collapsing vapor cavities in cavitating flow near solid boundaries, high pressure impact loads are generated. These pressure loads are believed to be responsible for the erosive damages on solid surface observed in most applications. For our investigation, the initial geometry is a single vapor bubble near a solid boundary collapsing due to the pressure difference between the bubble and surrounding liquid. The numerical approach employs a simplified homogenous mixture or 'single fluid' model with barotropic assumption in a fully compressible finite-volume fluid solver. The numerical method is validated against the well-known Rayleigh collapse of a pure 3D vapour bubble. It is then used for the simulation of a 2D vapour bubble collapsing in the proximity of a solid boundary placed at a specified distance from the centre of the bubble. The pressure loads are computed from the evolving dynamics of collapsing bubble near a solid boundary which can be used to determine the resulting surface deformation. The developed compressible cavitation solver in the CFD code 2 can efficiently model small and large scale cavitating structures in a fully resolved three dimensional flow

Modeling Fluid-Structure Interaction in Cavitation Erosion using Smoothed Particle Hydrodynamics

International audienceIn the present study a meshless Smoothed Particle Hydrodynamics cavitation solver is developed. The fluid bubble collapse solver is validated against analytical Rayleigh-Plesset equation and shows good agreement. The solid solver capable of solving elastic-plastic deformation and material damage is developed and is validated against FEM results. A fluid structure interaction solver capable of solving cavitation erosion is presented. A single bubble collapse is demonstrated in the paper

Karakterizacija hitrostrjenih trakov zlitine Cu-Al-Ni z uporabo fokusiranega ionskega curka

This work investigates the possibilities for applying a focussed ion beam (FIB) for the metallographic preparation and characterization of Cu-Al-Ni melt-spun ribbons. Two alloys were selected for this reason: CuAl13Ni4 and CuAl15Ni4. The microstructure of the first alloy was fully martensitic and the microstructure of the second consisted of two phases: martensite and ▫$gamma_2$▫. It was discovered that with FIB-etching the microstructures of both alloys can be clearly revealed on polished cross-sections of the melt-spun ribbons, as well as on their wheel-side and air-side surfaces. However, better results were obtained when the etched surface was smoother, and finer details were visible when using smaller ion currents. In addition, a study was made into the influence of platinum deposition on the quality of 3D-cross sections. It was found that Pt-deposition is necessary when the edge of the trench should be straight and sharp, and the surface of the 3D cross-section smooth. However, in this case, the microstructure of the ribbons free surface cannot be seen.V tem delu smo raziskali mo.nosti uporabe fokusiranega ionskega curka (FIB) pri metalografski pripravi in karakterizaciji hitro strjenih zlitin Cu-Al- Ni. Izbrali smo dve zlitini: CuAl13Ni4 in CuAl15Ni4. Mikrostruktura prve zlitine je bila v celoti martenzitna, medtem ko je bila mikrostruktura druge zlitine sestavljena iz dveh faz: martenzita in ▫$gamma_2$▫. Ugotovljeno je bilo, da lahko pri jedkanju z ionskim curkom odkrijemo mikrostrukturo tako na poliranih prečnih prerezih trakov, kot tudi na obeh prostih površinah hitrostrjenih trakov. Mikrostruktura se je boljše odkrila, če je bila raziskana površina bolj gladka, medtem ko smo lahko razločili drobnejše mikrostrukturne sestavine pri uporabi manjših ionskih tokov. Poleg tega smo študirali tudi vpliv nanosa platine na kakovost 3D-prečnih prerezov. Ugotovili smo, da je nanos platine smiselno uporabiti, če želimo zelo ravne in ostre robove reza ter gladko površino prečnega reza, vendar pa v tem primeru ne moremo videti mikrostrukture proste površine

Resistant grape varieties and market acceptance: An evaluation based on experimental economics

We analyze consumers' evaluations of white wines from resistant varieties, produced in the Languedoc winegrowing region of France (2016 vintage). We use the results from a laboratory experiment performed in Paris in June 2017, where a panel of more than one hundred and sixty consumers, regular buyers of this type of wine, were asked to evaluate a wine of the Bouquet 3159 grape variety (monogenic variety resistant to mildew and powdery mildew and optimized for quality) and compare it with two conventional wines of different quality levels, and with a certified organic wine of similar type and price. The environmental and health performances and the production methods of the different wines were quantified according to several indicators: Treatment frequency indicator (TFI) and pesticide residue analysis. The consumers first evaluated the wines after tasting, having been given only a minimum amount of information about the region of origin and the vintage, then again after receiving information on production methods and the levels of our indicators. The method used to lend credibility to individual valuations used experimental economics, via a mechanism based on direct disclosure of their willingness to pay (maximum purchase price for a bottle of wine according to available information). The results showed that, on a purely sensory level, consumers had difficulty in accepting wine from a resistant variety. We were then able to see that communication focusing on environmental and health performances very much improved the position of the resistant variety of wine, putting it ultimately at the top of the average qualitative evaluations. In economic terms, we show that this promotion results in high market share, gained from conventional wines. Market share losses were lower, however, for the premium conventional wine, suggesting that the higher quality wines would be less directly challenged by wines produced from resistant varieties

“Media Use and the Analytical Brain”: Screen-Based Media Use and Behavioral Preference in Indonesian Children: [“Penggunaan Media dan Otak Analitik”: Penggunaan Media Berbasis Layar dan Preferensi Perilaku Anak Indonesia]

This study aims to examine the relationship between screen-based media use and autistic features. The present study involved 207 parents of Indonesian children 4-6 years old and 10-12 years old. Parents completed several questionnaires addressing children screen-based activities and level of autistic traits. The questionnaires are: (1) a screen-based media survey; (2) Empathizing-Systemizing Quotients (EQ-SQ Child); and (3) The Autism Spectrum Quotient (AQ-Child). An online survey was utilized to collect all study data. The results showed that children spent more than four hours on average per day with media use. The regression analysis indicated that total time spent by children on media use shows a positive correlation with systemizing. The total time spent by children on media use also positively correlated with the extreme male brain condition. The total time spent on screen-based media use did not significantly contribute to explaining the variance of empathizing. However, empathizing is negatively correlated with time devoted in watching activities (television, videos, and movies) and playing video games. The more children spend time playing in video games, the more the autism quotient (AQ) score increases. Finally, the current study provides empirical evidence for a relation of screen-based media use and autistic features in children. The findings suggest that the duration of screen-time are significant predictors of systemizing and extreme male behavior, albeit the significance for empathizing depends on the type of media. The results highlight the clinical importance of examining screen-based media use among children.   Studi ini bertujuan untuk menguji hubungan antara penggunaan media berbasis layar dengan karakteristik autisme. Studi ini melibatkan 207 orang tua di Indonesia yang memiliki anak berusia 4-6 tahun dan 10-12 tahun. Orang tua menyelesaikan beberapa survei secara daring. Kuesioner tersebut terdiri dari: (1) survei mengenai durasi penggunaan media berbasis layar pada anak; (2) skala Empathizing-Systemizing Quotient (EQ-SQ Child); dan (3) skala Autism Spectrum Quotient (AQ-Child). Hasil studi menunjukkan bahwa anak menghabiskan waktu secara rerata lebih dari empat jam per hari dengan penggunaan media. Analisis regresi menunjukkan bahwa durasi total penggunaan media berkorelasi positif dengan tingkat sistemisasi anak dan extreme male brain behavior, namun tidak berkontribusi secara signifikan dalam menjelaskan tingkat empati anak. Tingkat empati secara spesifik berkorelasi negatif dengan waktu yang digunakan untuk aktivitas menonton (televisi, video, dan film) dan bermain video game. Semakin lama durasi anak bermain video game, maka skor autism quotient (AQ) juga meningkat. Dengan demikian, studi ini memberikan bukti empiris mengenai hubungan penggunaan media berbasis layar dengan karakteristik autisme pada anak. Durasi penggunaan media berbasis layar adalah prediktor yang siginifikan untuk tingkat sistemasi dan extreme male brain behavior, sedangkan tingkat berempati anak lebih dipengaruhi oleh jenis media. Hasil studi ini menyoroti pentingnya memperhatikan dampak dari penggunaan media berbasis layar pada anak

Urologist burnout: Frequency, causes, and potential solutions to an unspoken entity

Physician burnout has been linked to decreased job performance, increased medical errors, interpersonal conflicts, and depression. Recent multispecialty studies suggest that urologists have higher rates (up to 63.6%) of burnout compared to physicians in other specialties; however, these reports were limited by low sample sizes.1 We aimed to evaluate the prevalence of urologist burnout, verify risk factors, and recommend preventative measures and solutions for colleagues at risk or suffering from burnout. Urologist burnout is a true entity that transcends level of training and nationality. Its roots appear to be deep-seated in our tireless efforts to strive for excellence in care for our patients, our growing academic and research pursuits, and surmounting administrative responsibilities; these virtues, which are regarded as the foundations of our career successes, are often obtained at the expense of personal health and wellbeing, as well as family sacrifice. Various other medical societies have become increasingly vocal about the issue of physician burnout and have actively initiated successful strategies to minimize its impact on their members. As an organization with a strong national presence, the Canadian Urological Association (CUA) should promote tools to prevent and interventions to assist those at risk for and suffering from burnout. Increased awareness in the general medical community has led to strategies and tools that can help prevent, identify, or assist physicians in their recovery from burnout. The CUA should develop and facilitate access to information and offer comprehensive support for urologists struggling with burnout

Opto-PCB: Three demonstrators for optical interconnections

We report on a research project targeting optical waveguide integrated PCBs conducted within the European FP6 Network of Excellence on Micro-Optics NEMO. For three identified feature requests we have built three specific demonstrators respectively addressing the integration of active components, the fabrication of peripheral fibre ribbons and the integration of multiple layers of waveguides on the board