Direct crude oil cracking for producing chemicals: Thermal cracking modeling

[EN] The direct cracking of crude oil is an interesting option for producing cheaply large amounts of petrochemicals. This may be carried out with catalyst and equipment similar to that of catalytic cracking, but at a temperature range between that of standard catalytic cracking and steam cracking. Thermal cracking will play a role in the conversion, but is rarely disclosed in experimental or modeling work. Thus, a crude oil and its fractions were thermally cracked and the products yields were modeled using a 9 lumps cracking scheme. It was found that heavy fraction cracks twice as fast as diesel fraction and ten times faster than gasoline fraction, with activation energies in the 140-200 kJ/mol range. Selectivity to ethylene, propylene and butenes were found similar in the operating range explored.The authors thank Saudi Aramco for its material and financial support. Financial support by the Spanish Government-MINECO through programs "Severo Ochoa" (SEV 2012-0267) and CTQ2015-70126-R and by the Generalitat Valenciana through the Prometeo program (PROMETEOII/2013/011) is also acknowledged.Corma Canós, A.; Sauvanaud, LL.; Mathieu, Y.; Al-Bogami, S.; Bourane, A.; Al-Ghrami, M. (2018). Direct crude oil cracking for producing chemicals: Thermal cracking modeling. Fuel. 211:726-736. https://doi.org/10.1016/j.fuel.2017.09.099S72673621

Fecal Calprotectin Excretion in Preterm Infants during the Neonatal Period

Fecal calprotectin has been proposed as a non-invasive marker of intestinal inflammation in inflammatory bowel disease in adults and children. Fecal calprotectin levels have been reported to be much higher in both healthy full-term and preterm infants than in children and adults.To determine the time course of fecal calprotectin (f-calprotectin) excretion in preterm infants from birth until hospital discharge and to identify factors influencing f-calprotectin levels in the first weeks of life, including bacterial establishment in the gut.F-calprotectin was determined using an ELISA assay in 147 samples obtained prospectively from 47 preterm infants (gestational age, and birth-weight interquartiles 27–29 weeks, and 880–1320 g, respectively) at birth, and at 2-week intervals until hospital discharge. (p = 0.047).During the first weeks of life, the high f-calprotectin values observed in preterm infants could be linked to the gut bacterial establishment

Association of Killer Cell Immunoglobulin-Like Receptor Genes with Hodgkin's Lymphoma in a Familial Study

BACKGROUND: Epstein-Barr virus (EBV) is the major environmental factor associated with Hodgkin's lymphoma (HL), a common lymphoma in young adults. Natural killer (NK) cells are key actors of the innate immune response against viruses. The regulation of NK cell function involves activating and inhibitory Killer cell Immunoglobulin-like receptors (KIRs), which are expressed in variable numbers on NK cells. Various viral and virus-related malignant disorders have been associated with the presence/absence of certain KIR genes in case/control studies. We investigated the role of the KIR cluster in HL in a family-based association study. METHODOLOGY: We included 90 families with 90 HL index cases (age 16–35 years) and 255 first-degree relatives (parents and siblings). We developed a procedure for reconstructing full genotypic information (number of gene copies) at each KIR locus from the standard KIR gene content. Out of the 90 collected families, 84 were informative and suitable for further analysis. An association study was then carried out with specific family-based analysis methods on these 84 families. PRINCIPAL FINDINGS: Five KIR genes in strong linkage disequilibrium were found significantly associated with HL. Refined haplotype analysis showed that the association was supported by a dominant protective effect of KIR3DS1 and/or KIR2DS1, both of which are activating receptors. The odds ratios for developing HL in subjects with at least one copy of KIR3DS1 or KIR2DS1 with respect to subjects with neither of these genes were 0.44[95% confidence interval 0.23–0.85] and 0.42[0.21–0.85], respectively. No significant association was found in a tentative replication case/control study of 68 HL cases (age 18–71 years). In the familial study, the protective effect of KIR3DS1/KIR2DS1 tended to be stronger in HL patients with detectable EBV in blood or tumour cells. CONCLUSIONS: This work defines a template for family-based association studies based on full genotypic information for the KIR cluster, and provides the first evidence that activating KIRs can have a protective role in HL

Clostridia in Premature Neonates' Gut: Incidence, Antibiotic Susceptibility, and Perinatal Determinants Influencing Colonization

Although premature neonates (PN) gut microbiota has been studied, data about gut clostridial colonization in PN are scarce. Few studies have reported clostridia colonization in PN whereas Bacteroides and bifidobacteria have been seldom isolated. Such aberrant gut microbiota has been suggested to be a risk factor for the development of intestinal infections. Besides, PN are often treated by broad spectrum antibiotics, but little is known about how antibiotics can influence clostridial colonization based on their susceptibility patterns. The aim of this study was to report the distribution of Clostridium species isolated in feces from PN and to determine their antimicrobial susceptibility patterns. Additionally, clostridial colonization perinatal determinants were analyzed.Of the 76 PN followed until hospital discharge in three French neonatal intensive care units (NICUs), 79% were colonized by clostridia. Clostridium sp. colonization, with a high diversity of species, increased throughout the hospitalization. Antibiotic courses had no effect on the clostridial colonization incidence although strains were found susceptible (except C. difficile) to anti-anaerobe molecules tested. However, levels of colonization were decreased by either antenatal or neonatal (during more than 10 days) antibiotic courses (p = 0.006 and p = 0.001, respectively). Besides, incidence of colonization was depending on the NICU (p = 0.048).This study shows that clostridia are part of the PN gut microbiota. It provides for the first time information on the status of clostridia antimicrobial susceptibility in PN showing that strains were susceptible to most antibiotic molecules. Thus, the high prevalence of this genus is not linked to a high degree of resistance to antimicrobial agents or to the use of antibiotics in NICUs. The main perinatal determinant influencing PN clostridia colonization appears to be the NICU environment

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Le microbiote intestinal du nouveau-né prématuré (le genre Clostridium et l'espèce Clostridium butyricum)

Chez le nouveau-né prématuré l implantation du microbiote intestinal est considérée comme anormale, avec un retard d implantation des bactéries anaérobies, en particulier des bifidobactéries. Concernant la colonisation intestinale par le genre Clostridium les données sont rares, alors que ce genre est impliqué dans des pathologies digestives, notamment l entérocolite ulcéro-nécrosante (ECUN), première urgence gastro-intestinale chez le prématuré. Ce travail de thèse a eu deux objectifs : (1) étudier les espèces de Clostridium s implantant au niveau intestinal chez les nouveau-nés prématurés, et identifier les facteurs périnataux influençant la colonisation ; et (2) réaliser une étude fondamentale sur l espèce butyricum fréquemment impliquée dans l ECUN. Nous avons mis en évidence que les espèces C. perfringens, C. difficile, C. butyricum et C. paraputrificum font parties du microbiote intestinal du nouveau-né prématuré sain. Les souches colonisatrices sont sensibles aux antibiotiques anti-anaérobies (excepté C. difficile). Les antibiothérapies périnatale et néonatale influencent les niveaux de colonisation des clostridies. Le facteur majeur influençant la colonisation des Clostridium est le centre hospitalier, suggérant l importance de la colonisation à partir de l environnement. La comparaison différentielle des profils protéiques cytosoliques de souches de C. butyricum isolées de prématurés ayant développé ou non une pathologie de type ECUN et de la souche de référence VPI3266 a permis de mettre en évidence des différences au niveau métabolique. L existence d un lien entre les différences observées et des caractéristiques de virulence dans le cadre de l ECUN reste à démontrer.In the preterm neonates, the establishment of the intestinal microbiota is known to be abnormal, with a delay in the strictly anaerobic bacteria establishment, especially for bifidobacteria. As far as clostridia are concerned, data on their intestinal colonization neonates are scarce, although this genus is involved in gastrointestinal diseases, in particular in necrotizing enterocolitis (NEC), the main gastrointestinal emergency in premature neonates. This work aimed at (1) analyzing Clostridium species establishment in the gut of preterm neonates and identifying perinatal factors influencing this colonization, and (2) performing a basic study on the species C. butyricum commonly involved in NEC. We have shown that the species C. perfringens, C. difficile, C. butyricum and C. paraputrificum are part of the intestinal microbiota of healthy preterm neonates. Colonizing strains were sensitive to anti-anaerobic antibiotics (except C. difficile). The perinatal and neonatal antibiotic courses had influence on clostridial colonization levels. The major factor influencing the colonization was the hospital, suggesting the importance of the colonization from the environment. The comparison of the cytosolic protein profiles between C. butyricum strains isolated from premature neonates who developed or not a NEC and the reference strain VPI3266 highlighted differences in the metabolism. A link between the observed differences and virulence characteristics of the strains in terms of NEC onset remains to be demonstratedPARIS-BIUP (751062107) / SudocSudocFranceF