Non-destructive examination of the bonding interface in DEMO divertor fingers

Plasma facing components (PFCs) with tungsten (W) armor materials for DEMO divertor require a high heat flux removal capability (at least 10 MW/m² in steady-state conditions). The reference divertor PFC concept is a finger with a tungsten tile as a protection and sacrificial layer brazed to a thimble made of tungsten alloy W – 1% La₂O₃ (WL10). Defects may be located at the W thimble to W tile interface. As the number of fingers is considerable (>250,000), it is then a major issue to develop a reliable control procedure in order to control with a non-destructive examination the fabrication processes. The feasibility for detecting defect with infrared thermography SATIR test bed is presented. SATIR is based on the heat transient method and is used as an inspection tool in order to assess component heat transfer capability. SATIR tests were performed on fingers integrating or not the complex He cooling system (steel cartridge with jet holes). Millimeter size artificial defects were manufactured and their detectability was evaluated. Results of this study demonstrate that the SATIR method can be considered as a relevant non-destructive technique examination for the defect detection of DEMO divertor fingers.     

Numerical modelling of the electrochemical behaviour of 316L stainless steel based upon static and dynamic experimental microcapillary-based techniques

Microcapillary-based techniques allow the selection and interrogation of single metallurgical sites and are therefore becoming increasingly popular to investigate the electrochemical behaviour of metallic phases and non-metallic heterogeneities in alloys. This study has been carried out to assess the differences between current measurements made using a ‘closed’ microcapillary system (the electrochemical microcell technique) with current measurements derived from a flowing ‘open’ microcapillary droplet cell (the scanning droplet cell). The experimental results were compared with calculations derived from a model system adopting a finite element approach. The corrosion system consists of four parallel electrochemical reactions: three cathodic reactions (the oxygen reduction reaction, the hydrogen evolution reaction and water dissociation) and one anodic reaction (metal dissolution reaction). Comparative experimental results have shown there is a large discrepancy between the magnitudes of the cathodic current obtained by the two techniques. The results of this study allow an assessment of the parameters responsible for the mass transport and distribution of species in the closed and open systems. Critical parameters (for example, microcell crevice geometry, specimen surface-capillary gap distance, etc.) which lead to significant modifications of the curves were then identified using the numerical simulation.     

Intraperitoneal chemo-hyperthermia with mitomycin C in cancer of the stomach with peritoneal carcinosis

We report 42 cases of gastric cancer with peritoneal carcinosis treated with intraperitoneal chemohyperthermia. Intraperitoneal chemohyperthermia was achieved with a closed sterile circuit containing mitomycin C, 10 mg/l producing an input temperature varying from 46 to 49 degrees C for 90 minutes. There were three postoperative deaths: one pulmonary embolism at day 4, one multiple organ failure et day 4, and one septic shock at day 25 due to a colonic fistula. Two patients suffered complications: one opening of the duodenal stump requiring reoperation on day 5, and one prolonged postoperative ileus lasting to day 10. Of the 12 patients with ascites, resorption was achieved in 8. In patients with early-stage peritoneal carcinosis (granulations less than 5 mm) survival at 1, 2 and 3 years was 90%, 61% and 41% respectively. For those with more extensive carcinosis, survival at 1 year was 10%. Five patients survived more than 30 months, three have survived to 34, 43 and 73 months. Intraperitoneal chemohyperthermia is a new treatment for carcinosis of gastric origin. These early results must be assessed further with larger controlled.     

RhoG GTPase controls a pathway that independently activates Rac1 and Cdc42Hs

RhoG is a member of the Rho family of GTPases that shares 72% and 62% sequence identity with Rac1 and Cdc42Hs, respectively. We have expressed mutant RhoG proteins fused to the green fluorescent protein and analyzed subsequent changes in cell surface morphology and modifications of cytoskeletal structures. In rat and mouse fibroblasts, green fluorescent protein chimera and endogenous RhoG proteins colocalize according to a tubular cytoplasmic pattern, with perinuclear accumulation and local concentration at the plasma membrane. Constitutively active RhoG proteins produce morphological and cytoskeletal changes similar to those elicited by a simultaneous activation of Rac1 and Cdc42Hs, i.e., the formation of ruffles, lamellipodia, filopodia, and partial loss of stress fibers. In addition, RhoG and Cdc42Hs promote the formation of microvilli at the cell apical membrane. RhoG-dependent events are not mediated through a direct interaction with Rac1 and Cdc42Hs targets such as PAK-1, POR1, or WASP proteins but require endogenous Rac1 and Cdc42Hs activities: coexpression of a dominant negative Rac1 impairs membrane ruffling and lamellipodia but not filopodia or microvilli formation. Conversely, coexpression of a dominant negative Cdc42Hs only blocks microvilli and filopodia, but not membrane ruffling and lamellipodia. Microtubule depolymerization upon nocodazole treatment leads to a loss of RhoG protein from the cell periphery associated with a reversal of the RhoG phenotype, whereas PDGF or bradykinin stimulation of nocodazole-treated cells could still promote Rac1- and Cdc42Hs-dependent cytoskeletal reorganization. Therefore, our data demonstrate that RhoG controls a pathway that requires the microtubule network and activates Rac1 and Cdc42Hs independently of their growth factor signaling pathways.     

Local electrochemical studies after heat treatment of stainless steel: Role of induced metallurgical and surface modifications on pitting triggering

The morphology, the chemical composition, and the pitting corrosion resistance of a resulfurized stainless steel heated at 1000 °C for 2 hours were investigated at the microscale using ex-situ (field-emission-scanning electron microscope/electron dispersion spectrometer (FE-SEM/EDS) and secondary ion mass spectroscopy (SIMS)) and in-situ (electrochemical microcell technique and in-situ atomic force microscope (AFM) techniques. Although microcracks, which may have a deleterious effect, exist, the formation of a compound (Cr,Mn)₂(O,S)₃ instead of MnS is responsible for the better pitting corrosion resistance of sites containing an inclusion. Local electrochemical measurements indicate that no pitting was detected on these sites below 800 mV/SCE (saturated calomel electrode), whereas stable pitting was observed at around 350 mV/SCE before heating. Micropores were detected on the highly oxidized grains in which the ionic activity was found to be more marked than on the remaining surface (determined using in-situ AFM). Local electrochemical measurements revealed that the presence of such defects reduces significantly the corrosion resistance of the metallic alloy in NaCl-based media.     

A new series of imidazolones: highly specific and potent nonpeptide AT1 angiotensin II receptor antagonists

Starting from the structure of the novel nonpeptide AT1 receptor antagonist DuP 753 (losartan), a new series of potent antagonists was designed. In these compounds the central imidazole nucleus was replaced by the dihydroimidazol-4-one structure. The most active compounds had a spirocyclopentane or a spirocyclohexane ring in position 5. Like the imidazole series, the best substituents were the linear butyl chain in position 1 and the [2'-(tetrazol-5-yl)biphenylyl]methyl group in position 3. Antagonistic activity was assessed by the ability of the compounds to competitively inhibit [125I]AII binding to the AT1 subtype receptor and to antagonize AII-induced contractions in rabbit aorta rings. The most active compounds had IC50 values in the nanomolar range. In conscious rats, compounds 4 and 21 antagonized the AII pressor response when administered orally. Compound 21 (SR 47436) was the most active; it was recently shown to also be active in cynomolgus monkeys both intravenously and orally. This molecule is now undergoing clinical trials for the treatment of hypertension.     

Social media crisis management: Aligning corporate response strategies with stakeholders’ emotions online

The article focuses on how the analysis of stakeholders’ emotions online can help companies facing a social media crisis determine the response strategy that will best minimize the reputational threat. The article indeed questions the relevance of classical crisis management theory to an online environment. Results show that social media have increased the unpredictability of corporate crises. Consequently, on social media, crises cannot be addressed with the methods that have prevailed so far. Rather, incorporating emotion‐based analysis in six case studies showed how crisis analysis, and the subsequent response strategy, could be fine‐tuned. The article builds on recent literature to develop a new analytical framework for response strategies and a model for crisis resolution—the social media crisis management matrix.     

Effects of urban coarse particles inhalation on oxidative and inflammatory parameters in the mouse lung and colon

Background

Air pollution is a recognized aggravating factor for pulmonary diseases and has notably deleterious effects on asthma, bronchitis and pneumonia. Recent studies suggest that air pollution may also cause adverse effects in the gastrointestinal tract. Accumulating experimental evidence shows that immune responses in the pulmonary and intestinal mucosae are closely interrelated, and that gut-lung crosstalk controls pathophysiological processes such as responses to cigarette smoke and influenza virus infection. Our first aim was to collect urban coarse particulate matter (PM) and to characterize them for elemental content, gastric bioaccessibility, and oxidative potential; our second aim was to determine the short-term effects of urban coarse PM inhalation on pulmonary and colonic mucosae in mice, and to test the hypothesis that the well-known antioxidant N-acetyl-L-cysteine (NAC) reverses the effects of PM inhalation.

Results

The collected PM had classical features of urban particles and possessed oxidative potential partly attributable to their metal fraction. Bioaccessibility study confirmed the high solubility of some metals at the gastric level. Male mice were exposed to urban coarse PM in a ventilated inhalation chamber for 15 days at a concentration relevant to episodic elevation peak of air pollution. Coarse PM inhalation induced systemic oxidative stress, recruited immune cells to the lung, and increased cytokine levels in the lung and colon. Concomitant oral administration of NAC reversed all the observed effects relative to the inhalation of coarse PM.

Conclusions

Coarse PM-induced low-grade inflammation in the lung and colon is mediated by oxidative stress and deserves more investigation as potentiating factor for inflammatory diseases.

     

A multi-agent system simulating human splice site recognition.

The present paper describes a method detecting splice sites automatically on the basis of sequence data and models of site/signal recognition supported by experimental evidences. The method is designed to simulate splicing and while doing so, track prediction failures, missing information and possibly test correcting hypotheses. Correlations between nucleotides in the splice site regions and the various elements of the acceptor region are evaluated and combined to assess compensating interactions between elements of the splicing machinery. A scanning model of the acceptor region and a model of interaction between the splicing complexes (exon definition model) are also incorporated in the detection process. Subsets of sites presenting deficiencies of several splice site elements could be identified. Further examination of these sites helps to determine lacking elements and refine models.     

准中性等离子体模拟中的两种渐近保持PIC算法研究

针对准中性无碰撞等离子体的Vlasov方程及与其相耦合的求解电势的Poisson方程所组成的Vlasov-Poisson系统,提出了两种渐近保持PIC算法,并将其运用到一维周期性波动等离子体模型上。与传统PIC算法相比较,两种渐近保持PIC算法解决了Vlasov-Poisson系统多尺度参数中的小量束缚问题,时间和空间步长的选取可以克服传统粒子模型中等离子体周期及德拜长度的限制,且模拟结果稳定正确,大大提高了计算效率。