Noble gas in densified liquid and amorphous silica and thermodynamic conditions for the emergence of bubbles

Different noble gases (He, Ne, and Ar) containing densified silica liquids and glasses are investigated from molecular dynamics simulations at different system densities using a dedicated force field. The results for pure silica are first compared to reference potentials prior to an investigation of the thermodynamic diagram, the diffusivity, and the structure under different (T, P) conditions. It is found that the equation of state and the diffusivity are weakly sensitive to the nature of the incorporated noble gas, leading to a similar trend with density for all systems. The network structure is weakly altered by the presence of the gas, and pressure induced structural changes are those usually found for amorphous and liquid silica, i.e., Si coordination increase, tetrahedral to octahedral conversion of the base geometry, and collapse of large rings under pressure. Ne- and Ar-based systems display an increased structuration, however, as preferential distances appear in gas-gas correlations at large densities in both the liquid and amorphous states. Finally, we focus on the conditions of heterogeneity that are driven by the formation of noble gas bubbles, and these appear for a threshold density ρ_c that is observed for all systems.

The fingerprint of the summer 2018 drought in Europe on ground-based atmospheric CO2 measurements

During the summer of 2018, a widespread drought developed over Northern and Central Europe. The increase in temperature and the reduction of soil moisture have influenced carbon dioxide (CO₂) exchange between the atmosphere and terrestrial ecosystems in various ways, such as a reduction of photosynthesis, changes in ecosystem respiration, or allowing more frequent fires. In this study, we characterize the resulting perturbation of the atmospheric CO₂ seasonal cycles. 2018 has a good coverage of European regions affected by drought, allowing the investigation of how ecosystem flux anomalies impacted spatial CO₂ gradients between stations. This density of stations is unprecedented compared to previous drought events in 2003 and 2015, particularly thanks to the deployment of the Integrated Carbon Observation System (ICOS) network of atmospheric greenhouse gas monitoring stations in recent years. Seasonal CO₂ cycles from 48 European stations were available for 2017 and 2018. Earlier data were retrieved for comparison from international databases or national networks. Here, we show that the usual summer minimum in CO₂ due to the surface carbon uptake was reduced by 1.4 ppm in 2018 for the 10 stations located in the area most affected by the temperature anomaly, mostly in Northern Europe. Notwithstanding, the CO₂ transition phases before and after July were slower in 2018 compared to 2017, suggesting an extension of the growing season, with either continued CO₂ uptake by photosynthesis and/or a reduction in respiration driven by the depletion of substrate for respiration inherited from the previous months due to the drought. For stations with sufficiently long time series, the CO₂ anomaly observed in 2018 was compared to previous European droughts in 2003 and 2015. Considering the areas most affected by the temperature anomalies, we found a higher CO₂ anomaly in 2003 (+3 ppm averaged over 4 sites), and a smaller anomaly in 2015 (+1 ppm averaged over 11 sites) compared to 2018. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

[Hypnotherapy in psycho-oncology : clinical benefits and future prospects]

After a cancer diagnosis, emotional distress is common. We currently have many conventional treatments such as radiotherapy, surgery, chemotherapy, targeted therapies and immunotherapy to fight cancer. However, these treatments are associated with significant adverse effects, which may themselves be the cause of psychic suffering. Hypnosis has been shown to be effective in relieving some of these symptoms, but its practice is still limited in oncology. This is as much related to ignorance about the discipline as to a lack of large randomized prospective studies. This article provides an overview of hypnotherapy and its benefits in the field of psycho-oncology and discusses the prospects for the future.

A statistical evaluation of the influence of housing characteristics and geogenic radon potential on indoor radon concentrations in France

Radon-222 is a radioactive natural gas produced by the decay of radium-226, known to be the main contributor to natural background radiation exposure. Effective risk management needs to determine the areas in which the density of buildings with high radon levels is likely to be highest. Predicting radon exposure from the location and characteristics of a dwelling could also contribute to epidemiological studies. Beginning in the nineteen-eighties, a national radon survey consisting in more than 10,000 measurements of indoor radon concentrations was conducted in French dwellings by the Institute for Radiological Protection and Nuclear Safety (IRSN). Housing characteristics, which may influence radon accumulation in dwellings, were also collected. More recently, the IRSN generated a French geogenic radon potential map based on the interpretation of geological features. The present study analyzed the two datasets to investigate the factors influencing indoor radon concentrations using statistical modeling and to determine the optimum use of the information on geogenic radon potential that showed the best statistical association with indoor radon concentration. The results showed that the variables associated with indoor radon concentrations were geogenic radon potential, building material, year of construction, foundation type, building type and floor level. The model, which included the surrounding geogenic radon potential (i.e. the average geogenic radon potential within a disc of radius 20 km centered on the indoor radon measurement point) and variables describing house-specific factors and lifestyle explained about 20% of the overall variability of the logarithm of radon concentration. The surrounding geogenic radon potential was fairly closely associated with the local average indoor radon concentration. The prevalence of exposure to radon above specific thresholds and the average exposures to radon clearly increased with increasing classes of geogenic radon potential. Combining the two datasets enabled improved assessment of radon exposure in a given area in France.

Mortality associated with chronic external radiation exposure in the French combined cohort of nuclear workers

OBJECTIVE

The long-term effects of protracted low level ionising radiation exposure are investigated in a combined analysis of French nuclear workers employed by the Commissariat à l'Energie Atomique (CEA), AREVA Nuclear Cycle (AREVA NC) and Electricité de France (EDF). Associations between cumulative external radiation dose and mortality due to solid cancers, leukaemia and circulatory disease were examined.

METHODS

All workers hired by CEA, AREVA NC and EDF between 1950 and 1994 who were employed for at least 1 year, badge-monitored for radiation exposure and alive on 1 January 1968 were included. Individual data of annual exposure to penetrating photons (X-rays and gamma rays) were reconstructed for each worker. Estimates of radiation dose-mortality associations were obtained using a linear excess relative risk (ERR) Poisson regression model.

RESULTS

Among the 59 021 nuclear workers, 2312 died of solid cancer, 78 of leukaemia and 1468 of circulatory diseases during the 1968-2004 period. Approximately 72% of the cohort had a non-zero cumulative radiation dose estimate, with a mean cumulative dose of 22.5 mSv. Positive but non-significant ERR/Sv were observed for all solid cancers, leukaemia excluding chronic lymphocytic leukaemia (CLL), ischaemic heart diseases and cerebrovascular diseases. A significant ERR/Sv was found for myeloid leukaemia.

CONCLUSIONS

This is the first combined analysis of major French cohorts of nuclear workers. Results were consistent with risks estimated in other nuclear worker cohorts and illustrate the potential of a further joint international study to yield direct risk estimates in support to radiation protection standards.

Preoperative imaging in the planning of deep inferior epigastric artery perforator flap surgery

Breast reconstruction with adipocutaneous free flap from the abdominal wall combines the benefits of abdominoplasty to those of a prosthesis-free breast reconstruction. The deep inferior epigastric artery perforator (DIEP) flap is supplied by intramuscular perforators from the deep inferior epigastric artery (DIEA). It consists of the dissection of perforating branches of the DIEA within the rectus abdominis muscle, thus sparing both muscle and fascia. Preoperative imaging in the planning of DIEP flap surgery has been shown to facilitate faster and safer surgery. This review article aims to discuss advantages and drawbacks of current imaging modalities for mapping the course of perforating vessels in the planning of DIEP flap surgery, and to present state-of-the-art imaging techniques.

Toxic megacolon in patients with severe acute colitis: computed tomographic features

OBJECTIVE

The objective of the study was to evaluate computed tomography (CT) in the differential diagnosis of patients with toxic megacolon (TM) complicating severe acute colitis (SAC) and patients with SAC but no TM.

MATERIALS AND METHODS

We identified 16 patients who presented clinically complicated SAC and CT examination before surgery. The CT scans of these patients were retrospectively evaluated in consensus by two abdominal radiologists blinded to the clinical and pathological results for CT findings of SAC, i.e., diffuse colonic wall thickening, submucosal edema, pericolonic fat stranding and ascites, and CT findings of TM reported in the literature, i.e., segmental colonic wall thinning, air-filled colonic distension over 6 cm with abnormal haustral pattern, nodular pseudopolyps and associated small bowel distension. Fisher's Exact Test was used for all statistical analyses.

RESULTS

Segmental colonic wall thinning with abnormal haustral pattern was noted in TM only (P=.001). As compared to patients with SAC but no TM as a complication, patients with TM showed statistically more frequent air-filled colonic distension over 6 cm (P=.001) and nodular pseudopolyps (P=.001). Diffuse colonic wall thickening (P=.036) and submucosal edema (P=.036) were more present in cases of uncomplicated SAC. Pericolonic fat stranding (P=.12), ascites (P=.6), and small bowel and gastric distension (P=1) were not distinctive criteria.

CONCLUSION

Computed tomography is useful in distinguishing patients with TM from patients with SAC but no TM as a complication. The association of air-filled colonic distension >6 cm, abnormal haustral pattern and segmental colonic parietal thinning seems pathognomonic of TM and should lead to rapid surgery.

Asthma attacks and deprivation: gradients in use of mobile emergency medical services

BACKGROUND

To test whether rates of emergency telephone calls for asthma attacks are associated with contextual socioeconomic deprivation in the Strasbourg metropolitan area (France).

METHODS

Two mobile emergency medical service networks provided all data for 2000-2005 about emergency calls for asthma attacks, georeferenced by census block. Contextual deprivation was measured for each census block by a composite index, constructed by principal component analysis. Emergency call rates were calculated for each census block and for different age groups. Empirical Bayesian smoothing was used to reduce the instability of outlying rates.

RESULTS

Positive spatial autocorrelation was detected in both the health and the socioeconomic datasets. In all age groups, rates of calls for asthma attacks increased linearly with deprivation. Correlation coefficients between these two factors varied according to age group: 0.53 for the group aged 0-9 years, 0.46 for 10-19 years, 0.65 for 20-39 years, 0.70 for 40-64 years, 0.68 for 65 and older, and 0.77 for the age-standardised incidence ratio. These correlation coefficients were highly significant (p<0.01), even after spatial autocorrelation was taken into account.

CONCLUSION

The socioeconomic gradients observed are consistent with those observed for severe forms of asthma and asthma hospitalisations in Western countries.

[Study of the coverage of pollen capture in Lyon over three seasons (1999, 2000, 2001)]

For the third consecutive year, the two sensors of the type HIRST of the National Network of aerobiology monitoring (RNSA) worked on the agglomeration of Lyon. The primary trap (Lyon 1) is located at 26 m height on a roof in southern zone of Lyon (district of Gerland), the second (Lyon 2) is located in northern zone of the city (district of Vaise) on a roof at 15 m height compared to the ground. The study of the daily variations of the pollinic counts over the first two years had shown a perfect parallelism for pollens of trees, Poaceae and Urticaceae. Only the curves of pollens of ambrosia presented different layouts between the two pollen traps. The study of this third year makes it possible to consolidate the proceeding results and to appreciate the value of the cover of a Hirst pollen trap in urban implantation within the framework of the allergo-pollinic monitoring.

EuroBionet: a pan-European biomonitoring network for urban air quality assessment

EuroBionet, the 'European Network for the Assessment of Air Quality by the Use of Bioindicator Plants', is an EU-funded cooperative project currently consisting of public authorities and scientific institutes from 12 cities in 8 countries. In 2000, the bioindicator plants tobacco (Nicotiana tabacum Bel W3), poplar (Populus nigra 'Brandaris'), spiderwort (Tradescantia sp. clone 4430), Italian rye grass (Lolium multiflorum italicum) and curly kale (Brassica oleracea acephala) were exposed to ambient air at 90 monitoring sites according to standardised methods. Visible injuries and growth parameters were assessed and the accumulation of toxic substances in leaves determined. The exposure of tobacco resulted in a gradient with low levels of ozone-induced foliar injury in N and NW Europe, and medium to high values in the southern and central regions. The results of heavy metal and sulphur analyses in rye grass samples generally showed low to very low sulphur and low to medium heavy metal concentrations in leaves. In some cities, however, local hot spots of heavy metal contamination were detected. Analyses of the PAH contents in curly kale leaves gave low to medium values, with locally elevated levels at traffic-exposed sites.

In vitro reconstituted Dictyostelium discoideum early endosome fusion is regulated by Rab7 but proceeds in the absence of ATP-Mg2+ from the bulk solution

We characterized the in vitro fusion of endosomal compartments from Dictyostelium discoideum. Fusion activity was restricted to early compartments, was dependent on cytosolic proteins, and was activated by GTP and guanosine 5'-O(3-thio)triphosphate (GTPgammaS). This stimulation suggests the involvement of a small G protein, which we propose to be Rab7 on the basis of the strong inhibitory effect of anti-Rab7 antibodies. It is noteworthy that in the presence of GTPgammaS, the concentration of ATP-Mg2+ could be reduced to less than 1 nM without loss of fusion activity. Under these conditions, competing residual ATP with adenosine 5'-O-(3-thio)triphosphate-Mg2+ also failed to inhibit endosome fusion. The presence of an ATP-depleting system alone blocked fusion probably because endogenous GTP was removed by coupling through NDP kinase. Moreover, whether ATP was present or not, GTPgammaS-activated fusion was equally sensitive to anti-Rab7 antibodies or N-ethylmaleimide and was restricted to early compartments. These results show that soluble ATP-Mg2+ is not needed for endosome fusion. Since homotypic fusion of endosomes in D. discoideum has been shown to depend on the ATPase N-ethylmaleimide-sensitive factor (Lenhard, J. M., Mayorga, L. , and Stahl, P. D. (1992) J. Biol. Chem. 267, 1896-1903), the nucleotide exchange on the N-ethylmaleimide sensitive factor must take place before GTPgammaS activation in this system.

[What is the current thinking on the biorhythm theory?]

Biorhythm theory, if it seems to know a certain success with the public, however, remains ignored by the medical world, in spite of the fact that it claims to be a means of medical safety.