Shell (France)

Methyl methacrylate (MMA) is a specialty monomer for poly methyl methacrylate (PMMA) and the increasing demand for this monomer has motivated industry to develop clean technologies based on renewable resources. The dominant commercial process reacts acetone and hydrogen cyanide to MMA (ACH route) but the intermediates (hydrogen cyanide, and acetone cyanohydrin) are toxic and represent an environmental hazard. Esterification of methacrylic acid (MAA) to MMA is a compelling alternative together with ethylene, propylene, and isobutene/t-butanol as feedstocks. Partially oxidizing isobutane or 2-methyl-1,3-propanediol (2MPDO) over heteropolycompounds to MAA in a single-step is nascent technology to replace current processes. The focus of this review is on catalysts and their role in the development of processes herein described. Indeed, in some cases remarkable catalysts were studied that enabled considerable steps forward in both the advancement of catalysis science and establishing the basis for new technologies. An emblematic example is represented by Keggin-type heteropolycompounds with cesium and vanadium, which are promising catalysts to convert isobutane and 2MPDO to MAA. Renewable sources for the MMA or MAA route include acetone, isobutanol, ethanol, lactic, itaconic, and citric acids. End-of-life PMMA is expected to grow as a future source of MMA.

OBJECTIVE: To determine whether Candida albicans airway colonization influences Pseudomonas aeruginosa pneumonia prevalence in rats and by which mechanism. DESIGN: Prospective, randomized, controlled animal study. SETTING: Research laboratory of a university. SUBJECTS: Male adult Wistar rats weighing 275-300 g. INTERVENTIONS: In vivo: P. aeruginosa pneumonia was induced by bronchial instillation of P. aeruginosa in rats previously instilled or not with live or ethanol-killed C. albicans. In vitro: Alveolar macrophages were incubated with or without live or ethanol-killed C. albicans. MEASUREMENTS AND MAIN RESULTS: Quantitative cultures of lung were done. Lung tumor necrosis factor alpha, interferon gamma, and interleukin-6 levels were measured along with reactive oxygen species (ROS) production by alveolar macrophages. P. aeruginosa pneumonia prevalence was higher in rats given live but not ethanol-killed C. albicans. Instilling live C. albicans alone increased lung tumor necrosis factor-alpha and interferon-gamma but not interleukin-6, and was not associated with clinical or histologic signs of infection. These three cytokines were more abundant in lungs instilled with live C. albicans and P. aeruginosa than in those instilled with P. aeruginosa alone or with ethanol-killed C. albicans and P. aeruginosa. Alveolar macrophages incubated with live C. albicans had decreased ROS production. CONCLUSIONS: C. albicans impedes alveolar macrophage ROS production and is correlated with an increase of P. aeruginosa pneumonia prevalence in rats. These results highlight the previously overlooked impact of airway fungal colonization on lung bacterial infection, and indicate the need for studies on the potential for antifungal therapy to prevent the onset of ventilator-associated pneumonia caused by P. aeruginosa.

The object of the present study was to test the hypotheses of possible relationships between the amplitude A of the oral temperature circadian rhythm and (a) tolerance to shift-work on the one hand, (b) the speed of adjustment on shift-work on the other hand. 29 oil refinery shift-workers (on a 3-4 day rotation system) volunteered for the study. Four groups were formed. (I) 6 young operators with no medical complaint; subjects’ age: 21 to 35 y: shift-work duration: 1 to 4 y. (II) 10 senior operators with no medical complaint; 44 to 57 y; shift-work duration: 15 to 32 y. (111) 6 senior operators with minor medical complaints; 46 to 56 y; shift-work duralion:22 to 31 y. (IV) 7 senior operators with major medical complaints (persisting fatigue during rest and days off; deep subjective deterioration of sleep; use of sleeping pills etc.): 30 to 56 y of age, shift-work duration: 9 to 29 y. Oral temperatures were self-measured and recorded every 4 h, at fixed limes, over a 3 to 4 week span in order to obtain for each subject a longitudinal limes series of about 100 data. In addition, characteristics of sleep and fatigue were self-rated daily on special sheets. Both conventional and cosinor methods were used for statistical analyses. A circadian rhythm is validated in the 4 groups without differences in mesor (24 h adjusted average) nor in acrophase (crest location in the 24 h scale). A fall in the amplitude A is observed in group IV of non-toleranl subjects (2A=0.46°C; from 0.34 to 0 58 with 95% confidence limits) in comparison with group I (2A = 0.74°C: from 0 58 to 0 90) and group 11 (2A =0 70°C; from 0.60 to 0.80). A negative correlation (r = 0.55; p<0.01) is found between A and the acrophase shift δϕ resulting from night-shifts: the larger the amplitude, the smaller the δϕ Thus, the hypotheses tested can be regarded as complementary: a subject tolerant to shift work over several years is likely: (1) to have a large amplitude of the temperature circadian rhythm and (2) to adjust slowly during the night-shift (small δϕ).

Abstract The Tool to Estimate Land Surface Emissivity from Microwave to Submillimeter Waves (TELSEM2) is linked to a climatology of monthly emissivity estimates and provides a parameterization of the surface emissivity up to 700 GHz, in the framework of the preparation for the Ice Cloud Imager (ICI) on board the Meteorological Operational Satellite Second Generation (MetOp-SG). It is an updated version of the Tool to Estimate Land Surface Emissivities at Microwave Frequencies (TELSEM; Aires et al. 2011). This study presents the parameterization of continental snow and ice and sea ice emissivities in TELSEM2. It relies upon satellite-derived emissivities up to 200 GHz, and it is anchored to the Special Sensor Microwave Imager (SSM/I) TELSEM monthly climatology dataset (19–85 GHz). Emissivities from Météo-France and the National Oceanic and Atmospheric Administration (NOAA) at frequencies up to 190 GHz were used, calculated from the Special Sensor Microwave Imager/Sounder (SSMIS) and the Advanced Microwave Sounding Unit-B (AMSU-B) observations. TELSEM2 has been evaluated up to 325 GHz with the observations of the International Submillimeter Airborne Radiometer (ISMAR) and the Microwave Airborne Radiometer Scanning System (MARSS), which were operated on board the Facility for Airborne Atmospheric Measurements (FAAM) aircraft during the Cold-Air Outbreak and Submillimeter Ice Cloud Study (COSMICS) campaign over Greenland. Above continental snow and ice, TELSEM2 is very consistent with the aircraft estimates in spatially homogeneous regions, especially at 89 and 157 GHz. Over sea ice, the aircraft estimates are very variable spatially and temporally, and the comparisons with the TELSEM2 were not conclusive. TELSEM2 will be distributed in the new version of the RTTOV radiative transfer community code, to be available in 2017.

BACKGROUND: Open studies have reported favourable results for sacral nerve stimulation in the treatment of refractory constipation. Here, its efficacy was assessed in a double-blind crossover RCT. METHODS: Patients with at least two of the following criteria were included: fewer than three bowel movements per week; straining to evacuate on more than 25 per cent of attempts; or sensation of incomplete evacuation on more than 25 per cent of occasions. Response to therapy was defined as at least three bowel movements per week and/or more than 50 per cent improvement in symptoms. Responders to an initial 3-week peripheral nerve evaluation were offered permanent implantation of a pulse generator and were assigned randomly in a crossover design to two 8-week intervals of active or sham stimulation. At the end of the two trial periods, the patients received active stimulation until the final evaluation at 1 year. RESULTS: Thirty-six patients (34 women; mean(s.d.) age 45(14) years) underwent peripheral nerve evaluation. Twenty responded and received a permanent stimulator. A positive response was observed in 12 of 20 and 11 of 20 patients after active and sham stimulation periods respectively (P = 0·746). Pain related to the device occurred in five patients and wound infection or haematoma in three, leading to definitive removal of the pulse generator in two patients. At 1 year, 11 of the 20 patients with an implanted device continued to respond. Stimulation had no significant effect on colonic transit time. CONCLUSION: These results do not support the recommendation of permanent implantation of a pulse generator in patients with refractory constipation who initially responded to temporary nerve stimulation. Registration number: NCT01629303 (http://www.clinicaltrials.gov).

Oil and gas percolate profusely through the sediments of the Gulf of Mexico, leading to numerous seeps at the seafloor, where complex microbial, and sometimes animal communities flourish. Sediments from three areas (two cold seeps with contrasting hydrocarbon composition and a site outside any area of active seepage) of the Gulf of Mexico were investigated and compared. Consistent with the existence of a seep microbiome, a distinct microbial community was observed in seep areas compared to sediment from outside areas of active seepage. The microbial community from sediments without any influence from hydrocarbon seepage was characterized by Planctomycetes and the metabolic potential was consistent with detrital marine snow degradation. By contrast, in seep samples with methane as the principal hydrocarbon, methane oxidation by abundant members of ANME-1 was likely the predominant process. Seep samples characterized by fluids containing both methane and complex hydrocarbons, were characterized by abundant Chloroflexi (Anaerolinaceae) and deltaproteobacterial lineages and exhibited potential for complex hydrocarbon degradation. These different metabolic capacities suggested that microorganisms in cold seeps can potentially rely on other processes beyond methane oxidation and that the hydrocarbon composition of the seep fluids may be a critical factor structuring the seafloor microbial community composition and function.

Fully characterized HAP solids with various Ca/P ratios were used in the Guerbet reaction of ethanol to produce higher alcohols. In this respect, an optimal ratio between the amount of acid and basic sites of 5 was evidenced.

Exponentially converging observers are exhibited for a large class of multi-input multi-output (MIMO) nonlinear systems. Potential applications of these observers to mechanical systems and distillation columns are presented.>

We report the gas-phase hydrogenolysis of glycerol to 1,3-propanediol over Pt/WO 3 /Al 2 O 3 in a fluidized bed operating above 240 °C and at ambient pressure.

Both Fischer-Tropsch (FT) and Hydroprocessed Esters and Fatty Acids (HEFA) Synthetic Paraffinic Kerosine (SPK) fuels are considered as leading alternative replacements for conventional jet fuel. To satisfy the requirements of Civil Aviation Authorities (CAA), their drop-in incorporations have been subjected to a rigorous certification process. To reach the ambitious incorporation targets, new routes for biofuels incorporation may need to emerge, involving optimizing the production processes and the blending strategies. This paper focuses on a new strategy for incorporating HEFA, allowing the process yield to be optimised.

Abstract. An inverse error variance weighting of the anomalies of three terrestrial evaporation (ET) products from the WACMOS-ET project based on FLUXNET sites is presented. The three ET models were run daily and at a resolution of 25 km for 2002–2007, and based on common input data when possible. The local weights, derived based on the variance of the difference between the tower ET anomalies and the modelled ET anomalies, were made dynamic by estimating them using a 61-day running window centred on each day. These were then extrapolated from the tower locations to the global landscape by regressing them on the main model inputs and derived ET using a neural network. Over the stations, the weighted scheme usefully decreased the random error component, and the weighted ET correlated better with the tower data than a simple average. The global extrapolation produced weights displaying strong seasonal and geographical patterns, which translated into spatiotemporal differences between the ET weighted and simple average ET products. However, the uncertainty of the weights after the extrapolation remained large. Out-sample prediction tests showed that the tower data set, mostly located at temperate regions, had limitations with respect to the representation of different biome and climate conditions. Therefore, even if the local weighting was successful, the extrapolation to a global scale remains problematic, showing a limited added value over the simple average. Overall, this study suggests that merging tower observations and ET products at the timescales and spatial scales of this study is complicated by the tower spatial representativeness, the products' coarse spatial resolution, the nature of the error in both towers and gridded data sets, and how all these factors impact the weights extrapolation from the tower locations to the global landscape.

The cytotoxic, pyrazolato-bridged dinuclear platinum(II) complex [(cis-{Pt(NH3)2})2(mu-OH)(mu-pz)]2+ (pz=pyrazolate) has been found to cross-link two adjacent guanines of a double-stranded DNA decamer without destabilizing the duplex and without changing the directionality of the helix axis. A 1H NMR study of the oligonucleotide d(CTCTG*G*TCTC)-d(GAGACCAGAG), cross-linked at the two G* guanines by [(cis-{Pt(NH3)2})2(mu-pz)]3+, and molecular dynamics simulations of the explicitly solvated duplex were performed to characterize the structural details of the adduct. The dinuclear platinum cross-link unwinds the helix by approximately 15 degrees , that is, to a similar extent as the widely used antitumor drug cisplatin, but, in contrast to the latter, induces no significant bend in the helix axis. The Watson-Crick base-pairing remains intact, and the melting temperature of the duplex is unaffected by the cross-link. The helical twist is considerably reduced between the two platinated bases, as becomes manifest in an unusually short sequential H1'-H1' distance. This unwinding also affects the sugar ring of the guanosine in the 3'-position to the cross-link, which presents an N<-->S equilibrium. This is the first cytotoxic platinum complex that has been successfully designed by envisioning the structural consequences of its binding to DNA.

We conducted a retrospective multicenter study by questionnaire to evaluate the results of laparoscopic splenectomy for idiopathic thrombocytopenic purpura (ITP). Between 1991 and 1998, 209 patients with a mean age of 41.2 years (range, 10-83) had a laparoscopic splenectomy for idiopathic thrombocytopenic purpura. Preoperatively, 178 patients (85%) underwent medical treatment aimed at achieving a satisfactory platelet count. Twenty-nine patients were obese, with a body mass index greater than 30%, and 14% were HIV-seropositive. The so-called hanging spleen technique in the right lateral decubitus position was used most often. The average duration of surgery was 144 minutes (45-360). This was significantly longer in cases of conversion (170 minutes; P < 0.01). The factors influencing the duration of laparoscopy were operator experience and patient obesity (P < 0.01). A conversion was necessary in 36 cases (17.2%) because of hemorrhage. The conversion rate varied from 5.3% to 46.7%, depending on the surgical team. A multivariate analysis of factors disposing to conversion identified two causes: obesity and operator experience. One or more accessory spleens were found in 34 patients (16.2%). The average weight of the spleens was 194.2 g. There were no deaths. There were no complications in 187 patients (89.5%), with a mean hospital stay of 6.1 days. Patients who did not require a conversion had a significantly earlier return of intestinal transit, used less analgesic, and had a shorter length of hospitalization. Overall morbidity was 10.5% (22 cases), due to subphrenic collections (7 cases), abdominal wall complications (6 cases), re-intervention for actual or suspected hemorrhage or pancreatitis (3 cases), pneumopathology (2 cases) and others (4 cases). A multivariate analysis about morbidity shows a statistically significant difference in conversions (P < 0.05) but not in obesity or in surgeon's experience. Normal activity was achieved on average by the twentieth postoperative day--earlier if conversion was not required (18.4 versus 33.9 days). The average preoperative platelet count was 92.7 x 10(9)/L (range, 3 to 444). Twenty patients had a count of less than 30 x 10(9)/L and in this group the conversion rate was 30% (6 cases). Ninety-six patients were seen in the outpatient clinic, with an average follow-up time of 16.2 months (3 to 72 months), and the average platelet count was 242 x 10(9)/L (6 to 780). Eight patients (8.3%) were failures with a platelet count of <30 x 10(9)/L. In the 20 patients with a preoperative platelet count <30 x 10(9)/L, there were 3 early failures and 5 late relapses. There were 2 late deaths: chest infection at 3 months in an HIV seropositive patient and one case of pulmonary embolus at 6 months. Laparoscopic splenectomy constitutes a real alternative to conventional splenectomy for the treatment of idiopathic thrombocytopenic purpura. It is associated with fewer postoperative complications, a shorter duration of hospitalization and an earlier return to normal activity. The limiting factors are the experience of the operator and patient obesity. The long-term results are identical to those of conventional splenectomy, with a better than average success rate in patients that have failed preoperative medical treatment.

Abstract Long‐term satellite land surface temperature (LST) data are desirable to augment 2m air temperatures (T2m) measured in situ and as an independent measure of surface temperature change. However, previous studies show variable agreement between LST and T2m time series. The objective of this study is to assess the stability and trends in six new LST data sets from the European Space Agency's Climate Change Initiative for LST (LST_cci). LST anomalies are compared with homogenized station T2m anomalies over Europe, which verifies all six data sets are well coupled (LST vs T2m anomaly correlations and slopes: 0.6–0.9). The temporal stability of the LST_cci data is assessed through a comparison with the T2m anomaly time series. Only the LST_cci data sets for the MODerate resolution Imaging Spectroradiometer (MODIS) onboard Aqua and the Advanced Along‐Track Scanning Radiometer (AATSR) appear stable; the MODIS/Terra, ATSR‐2, and multisensor InfraRed and MicroWave data sets show non‐climatic discontinuities associated with changes in sensor and/or drift over time. For MODIS/Aqua (2002–2018), significant trends in LST of 0.64–0.66 K/decade compare well with the equivalent T2m trends of 0.52–0.59 K/decade. The LST and T2m trends for AATSR (2002–2012) are found to be statistically insignificant, likely due to the comparatively short study period and specific years available for analysis. No evidence is found to suggest that trends calculated using cloud‐free InfraRed observations are affected by clear‐sky bias. This study suggests that satellite LST data can be used to assess warming trends over land and for other climate applications if the required homogeneity is assured.

This study investigated the effects on the physiology of Pacific oyster, Crassostrea gigas, of a mixture of pesticides containing 0.8 μg L(-1) alachlor, 0.6 μg L(-1) metolachlor, 0.7 μg L(-1) atrazine, 0.6 μg L(-1) terbuthylazine, 0.5 μg L(-1) diuron, 0.6 μg L(-1) fosetyl aluminum, 0.05 μg L(-1) carbaryl, and 0.7 μg L(-1) glyphosate for a total concentration of 4.55 μg L(-1) . The total nominal concentration of pesticides mixture corresponds to the pesticide concentrations in the shellfish culture area of the Marennes-Oleron basin. Two varieties of C. gigas were selected on the foreshore, based on their characteristics in terms of resistance to summer mortality, to assess the effects of the pesticide mixture after 7 days of exposure under controlled conditions. The early effects of the mixture were assessed using enzyme biomarkers of nitrogen metabolism (GS, glutamine synthetase), detoxification metabolism (GST, glutathione S-transferase), and oxidative stress (CAT, catalase). Sublethal effects on hemocyte parameters (phagocytosis and esterase activity) and DNA damages (DNA adducts) were also measured. Changes in metabolic activities were characterized by increases in GS, GST, and CAT levels on the first day of exposure for the "resistant" oysters and after 3-7 days of exposure for the "susceptible" oysters. The formation of DNA adducts was detected after 7 days of exposure. The percentage of hemocyte esterase-positive cells was reduced in the resistant oysters, as was the hemocyte phagocytic capacity in both oyster varieties after 7 days of exposure to the pesticide mixture. This study highlights the need to consider the low doses and the mixture of pesticides to evaluate the effects of these molecules on organisms.

The magnitude of the circadian acrophase adjustment (Δφ) following a phase shift of socio-ecologtc synchronisers (Δψ) such as results from shift work varies from subject to subject. According to Aschoff (1976) the ability to adjust φ rapidly could be negatively related to the amplitude of certain circadian rhythms. To test this hypothesis the correlation coefficient (r) between the mean rhythm amplitude A and the acrophase shift Δφ after the first night shift was calculated for several variables from estimates of chronobiological time series analyses (single cosinor) in two groups of selected shift workers. Statistically significant negative correlations (ranging from −0.53 to −0.63) between A and Δφ were observed in the circadian rhythms of oral temperature, peak expiratory flow and urinary 17-OHCS, but not for grip strength, urinary K + and Na + A low amplitude of certain circadian rhythms could thus be considered as a measure of individual ability to adjust to shift work easily. It is posssible that other chronobiological characteristics may be found which will increase the value of this type of measure.

The RILEM TC-ATB-TG5, in charge of recycling of bituminous materials has decided to develop a laboratory procedure with the aim of reproducing the ageing of bituminous materials until the end of their service life (milled product). This procedure will help to assess the recyclability of mixtures and will allow Recycled Asphalt Pavement (RAP) production in the laboratory in a realistic way. The ageing of bituminous materials is mainly linked to the ageing of the binder and is normally separated into short and long-term ageing : The short-term ageing simulating ageing caused by the manufacture of the material in the mixing plant, transport and paving, especially the necessity to increase the binder temperature up to 160-190°C according to the type of binder and material to be manufactured. The long-term ageing simulating the influence of the climatic conditions and traffic loading on ageing during service life. In the framework of an LCPC fatigue carousel experiment, a bituminous material with a 35/50 pure bitumen was laid in January 2008. Loose mix and components (aggregates, bitumen) of the mix have been sampled to carry out a laboratory ageing round robin test, organised between the labs of the RILEM group. Also, on the fatigue carousel, coring will be carried out at several intervals to follow the evolution of the material. In this paper, a state of the art regarding the existing methodologies for the laboratory ageing of bituminous materials is presented as well as the round Robin test, including the tested ageing procedures and the tests chosen to validate these procedures according to the field site data. The first results are discussed with the focus on distribution analysis.

This study was designed to test the usefulness of the axillary temperature as a circadian marker rhythm, e.g. for shift workers in field experiments, where recordings may be required over extended periods. Axillary and rectal temperatures were recorded automatically at 5 or 15min intervals (Δt) using a ‘Chronotherm’ ambulatory system. Conventional (t-test, analysis of variance (ANOVA), correlation) and curve-fitting (cosinor) methods as well as power spectra were used for statistical analyses, (a) Rectal and axillary temperature rhythms were compared in five subjects over a 36 h span in laboratory conditions. Apart from rather small but constant differences in respective mesors (24 h mean) and acrophases (peak time location on the 24 h scale), rectal and axillary temperature recordings gave similar results in each individual. (b) In analyses of axillary temperatures recorded over periods of up to 15 days in a further five subjects (a field study with usual activities), only minor changes in circadian rhythm parameters were found to result from manipulation of the sampling interval over the range Δt= 15 min to Δt= 240 min, with or without data during sleep, (c) The axillary temperature recorded at Δt= 15 min over a 13 day span in a 32 year old worker on a 3-4 day rotating shift schedule had a prominent period (τ) of 22.3 h, although the prominent period of the rhythms of both wrist activity and the sleep-wake cycle remained unaltered at 24 h. Thus internal desynchronization was shown to have occurred in this subject.

One of the major assets of Model Predictive Controllers (MPCs) lies in their ability to manipulate constraints, both on inputs and outputs. When control objectives for process outputs are determined in terms of a bounded range, or if there are more inputs than outputs, it may happen that, even if all control objectives are satisfied, some degrees of freedom remain available. We can then envisage to use them for a steady state optimization. This paper describes the principle of incorporating a steady state economic optimization into a MPC. It allows to: • avoid offsets on controlled outputs because of inappropriate economic objectives given by an upper control level, • optimize a linear objective function subject to certain hypothesis. This optimizer is currently incorporated into the Shell Multivariable Optimizing Controller (SMOC) and is running with success in several Shell refineries.

Abstract Microbialites and peloids are commonly associated throughout the geologic record. Proterozoic carbonate megafacies are composed predominantly of micritic and peloidal limestones often interbedded with stromatolitic textures. The association is also common throughout carbonate ramps and platforms during the Phanerozoic. Recent investigations reveal that Hamelin Pool, located in Shark Bay, Western Australia, is a microbial carbonate factory that provides a modern analog for the microbialite-micritic sediment facies associations that are so prevalent in the geologic record. Hamelin Pool contains the largest known living marine stromatolite system in the world. Although best known for the constructive microbial processes that lead to formation of these stromatolites, our comprehensive mapping has revealed that erosion and degradation of weakly lithified microbial mats in Hamelin Pool leads to the extensive production and accumulation of sand-sized micritic grains. Over 40 km2of upper intertidal shoreline in the pool contain unlithified to weakly lithified microbial pustular sheet mats, which erode to release irregular peloidal grains. In addition, over 20 km2of gelatinous microbial mats, with thin brittle layers of micrite, colonize subtidal pavements. When these gelatinous mats erode, the micritic layers break down to form platey, micritic intraclasts with irregular boundaries. Together, the irregular micritic grains from pustular sheet mats and gelatinous pavement mats make up nearly 26% of the total sediment in the pool, plausibly producing ~ 24,000 metric tons of microbial sediment per year. As such, Hamelin Pool can be seen as a microbial carbonate factory, with construction by lithifying microbial mats forming microbialites, and erosion and degradation of weakly lithified microbial mats resulting in extensive production of sand-sized micritic sediments. Insight from these modern examples may have direct applicability for recognition of sedimentary deposits of microbial origin in the geologic record.