A primordial origin for the atmospheric methane of Saturn's moon Titan

The origin of Titan's atmospheric methane is a key issue for understanding the origin of the Saturnian satellite system. It has been proposed that serpentinization reactions in Titan's interior could lead to the formation of the observed methane. Meanwhile, alternative scenarios suggest that methane was incorporated in Titan's planetesimals before its formation. Here, we point out that serpentinization reactions in Titan's interior are not able to reproduce the deuterium over hydrogen (D/H) ratio observed at present in methane in its atmosphere, and would require a maximum D/H ratio in Titan's water ice 30% lower than the value likely acquired by the satellite during its formation, based on Cassini observations at Enceladus. Alternatively, production of methane in Titan's interior via radiolytic reactions with water can be envisaged but the associated production rates remain uncertain. On the other hand, a mechanism that easily explains the presence of large amounts of methane trapped in Titan in a way consistent with its measured atmospheric D/H ratio is its direct capture in the satellite's planetesimals at the time of their formation in the solar nebula. In this case, the mass of methane trapped in Titan's interior can be up to 1,300 times the current mass of atmospheric methane.Comment: Accepted for publication in Icaru

The impact of storms and stratification on sediment transport in the Rhine region of freshwater influence

We present measurements of along and across-shore sediment transport in a region of the Dutch coast 10 kilometers north of the Rhine River mouth. This section of the coast is characterized by strong vertical density stratification because it is within the mid-field region of the Rhine region of freshwater influence, where processes typical of the far-field, such as tidal straining, are modified by the passage of distinct freshwater lenses at the surface. The experiment captured two storms, and a wide range of wind, wave, tidal and stratification conditions. We focus primarily on the mechanisms leading to cross-shore sediment flux at a mooring location in 12m of water, which are responsible for the exchange of sediment between the near-shore and the inner shelf. Net transport during storms was directed offshore and influenced by cross-shelf winds, while net transport during spring tides was determined by the mean state of stratification. Tidal straining dominated during neap tides; however, cross-shore transport was negligible due to small sediment concentrations. The passage of freshwater lenses manifested as strong pulses of offshore transport primarily during spring tides. We observe that both barotropic and baroclinic processes are relevant for cross-shore transport at depth and, since transport rates due to these competing processes were similar, the net transport direction will be determined by the frequency and sequencing of these modes of transport. Based on our observations, we find that wind- and wave-driven transport during storms tends move fine sediment offshore, while calmer, more stratified conditions move it back onshore

Aspectos microbiológicos e epidemiológicos dos surtos causados por Salmonella sp em criações não industriais de Gallus gallus domesticus no Estado do Paraná

Orientador: Yasuyoshi HayashiDissertação (mestrado) - Universidade Federal do Parana, Setor de Ciencias AgrariasCom o objetivo de verificar a participação de Salmonella sp como causa de mortalidade entre as aves domésticas das criações caseiras no Estado do Paraná, foram analisadas, no período de 1987 a 1991, 671 amostras de aves, obtendo-se 7,0% de isolamento positivo, totalizando 47 cepas do microrganismo. Foram encontrados três sorovares causando doença, entre os quais, S.gallinarum (82,9%) responsável pela maioria dos surtos, seguido pela S.pullorum (12,7%) e S.enteritidis (4,2%). Vale ressaltar que o sorovar S.pullorum afetou somente as aves adultas. As 47 cepas de Salmonella pertenciam ao sorogrupo D1 , apresentando semelhante sensibilidade e resistência aos antibióticos e quimioterápicos quando testados "in vitro". Comprovou-se estatisticamente correlação entre o isolamento dos três sorovares citados com a morbidade e mortalidade ocorridas. Quanto ao sorovar S.gallinarum, as taxas médias de morbidade e mortalidade observadas nas aves consideradas jovens adultas (duas a oito semanas de idade) e adultas (mais de oito semanas de idade), situaram-se em 17 ,8%, 34,3% e 17,3%, 33,6%, respectivamente. No que se refere à S.pullorum as mesmas faixas etárias em relação a morbidade foram de 3,2% e 26,9% e mortalidade de 3,2% e 24,8%. S.enteritidis causou índices de morbidade de 23,8% e mortalidade de 22,6% somente na faixa etária das aves consideradas adultas. As aves jovens (1 a 14 dias de idade) não foram afetadas pela doença. Os percentuais de letalidade em relação à S.gallinarum, S.pullorum e S.enteritidis, foram de 97 ,9%, 93,3% e 95,0%, respectivamente. Observou-se ainda que a salmonelose ocorreu em todos os meses do ano. No entanto, quando distribuídos nas estações do ano, a primavera (31,9%) concentrou maior número de surtos, seguido do outono (25,5%), verão (23,4%) e inverno (19,1%)In order to check the role of the Salmonella as the cause of mortality of non commercial flocks of chicken in the State of Parana - Brazil, between 1987 and 1991, 671 samples were analyzed. The percentage of positive cases was 7,0%, comprising 47 different strains of the microorganism. Three serovars of Salmonella affected the birds. S.gallinarum was present in 82,9% of the outbreaks, S.pullorum in 12,7%, and S.enteritidis in only 4,2% of them. It is important to notice that S.pullorum affected only adult animals. When tested "in vitro" all the 47 strains of Salmonella belonged to the D1 serogroup, and showed similar resistance and sensitivity to antibacterial drugs. There is statistically significant correlation between the isolated serovars and the occurrence of morbidity and mortality .The mean rates of morbidity and mortality caused by the S.gallinarum serovar were respectively 17,8% and 34,3%, for young adults (two to eight weeks) and 17,3% and 33,6%, for adults (more than eight weeks). For the same are groups, the mean rates related to morbidity and mortality caused by S.pullorum was 3,2% and 26,9%, and 3,2% and 24,8%, respectively .The S.enteritidis affected only adult birds, causing 23,8% of morbidity and 22,6% of mortality. The group of young birds (one to 14 days) did not show morbidity or mortality .The lethality caused by S.gallinarum, S.pullorum and S.enteritidis was 97,9%, 93,3% and 95,0%, respectively. The salmonellosis was observed in all months of the year, with the greater number of outbreaks in the spring (31,9%). The percentages for the other seasons were 25,5%,23,4% and 19,1%, for the fallt, summer and winter, respectivel

Cross-shore stratified tidal flow seaward of a mega-nourishment

The Sand Engine is a 21.5 million m3 experimental mega-nourishment project that was built in 2011 along the Dutch coast. This intervention created a discontinuity in the previous straight sandy coastline, altering the local hydrodynamics in a region that is in influenced by the buoyant plume generated by the Rhine River. This work investigates the response of the cross-shore stratified tidal flow to the coastal protrusion created by the Sand Engine emplacement by using a 13 hour velocity and density survey. Observations document the development of strong baroclinic-induced cross-shore exchange currents dictated by the intrusion of the river plume fronts as well as the classic tidal straining which are found to extend further into the nearshore (from 12 to 6m depth), otherwise believed to be a mixed zone

Molecular pharmacodynamics of meropenem for nosocomial pneumonia caused by <i>Pseudomonas aeruginosa</i>.

ImportanceThe emergence of antimicrobial resistance (AMR) during antimicrobial treatment for hospital-acquired pneumonia (HAP) is a well-documented problem (particularly in pneumonia caused by Pseudomonas aeruginosa) that contributes to the wider global antimicrobial resistance crisis. During drug development, regimens are typically determined by their sufficiency to achieve bactericidal effect. Prevention of the emergence of resistance pharmacodynamics is usually not characterized or used to determine the regimen. The innovative experimental platform described here allows characterization of the emergence of AMR during the treatment of HAP and the development of strategies to mitigate this. We have demonstrated this specifically for meropenem-a broad-spectrum antibiotic commonly used to treat HAP. We have characterized the antimicrobial resistance pharmacodynamics of meropenem when used to treat HAP, caused by initially meropenem-susceptible P. aeruginosa, phenotypically and genotypically. We have also shown that intensifying the regimen and using combination therapy are both strategies that can both treat HAP and suppress the emergence of resistance

Chlamydia trachomatis infection increases fallopian tube PROKR2 via TLR2 and NFκB activation resulting in a microenvironment predisposed to ectopic pregnancy

Chlamydia trachomatis and smoking are major risk factors for tubal ectopic pregnancy (EP), but the underlying mechanisms of these associations are not completely understood. Fallopian tube (FT) from women with EP exhibit altered expression of prokineticin receptors 1 and 2 (PROKR1 and PROKR2); smoking increases FT PROKR1, resulting in a microenvironment predisposed to EP. We hypothesize that C. trachomatis also predisposes to EP by altering FT PROKR expression and have investigated this by examining NFkappaB activation via ligation of the Toll-like receptor (TLR) family of cell-surface pattern recognition receptors. PROKR2 mRNA was higher in FT from women with evidence of past C. trachomatis infection than in those without (P < 0.05), and was also increased in FT explants and in oviductal epithelial cell line OE-E6/E7 infected with C. trachomatis (P < 0.01) or exposed to UV-killed organisms (P < 0.05). The ability of both live and dead organisms to induce this effect suggests ligation of a cell-surface-expressed receptor. FT epithelium and OE-E6/E7 were both found to express TLR2 and TLR4 by immunohistochemistry. Transfection of OE-E6/E7 cells with dominant-negative TLR2 or IkappaBalpha abrogated the C. trachomatis-induced PROKR2 expression. We propose that ligation of tubal TLR2 and activation of NFkappaB by C. trachomatis leads to increased tubal PROKR2, thereby predisposing the tubal microenvironment to ectopic implantation

Energy compensation following consumption of sugar-reduced products: a randomized controlled trial

PURPOSE: Consumption of sugar-reformulated products (commercially available foods and beverages that have been reduced in sugar content through reformulation) is a potential strategy for lowering sugar intake at a population level. The impact of sugar-reformulated products on body weight, energy balance (EB) dynamics and cardiovascular disease risk indicators has yet to be established. The REFORMulated foods (REFORM) study examined the impact of an 8-week sugar-reformulated product exchange on body weight, EB dynamics, blood pressure, arterial stiffness, glycemia and lipemia. METHODS: A randomized, controlled, double-blind, crossover dietary intervention study was performed with fifty healthy normal to overweight men and women (age 32.0 ± 9.8 year, BMI 23.5 ± 3.0 kg/m2) who were randomly assigned to consume either regular sugar or sugar-reduced foods and beverages for 8 weeks, separated by 4-week washout period. Body weight, energy intake (EI), energy expenditure and vascular markers were assessed at baseline and after both interventions. RESULTS: We found that carbohydrate (P < 0.001), total sugars (P < 0.001) and non-milk extrinsic sugars (P < 0.001) (% EI) were lower, whereas fat (P = 0.001) and protein (P = 0.038) intakes (% EI) were higher on the sugar-reduced than the regular diet. No effects on body weight, blood pressure, arterial stiffness, fasting glycemia or lipemia were observed. CONCLUSIONS: Consumption of sugar-reduced products, as part of a blinded dietary exchange for an 8-week period, resulted in a significant reduction in sugar intake. Body weight did not change significantly, which we propose was due to energy compensation

Food allergy: recent advances in pathophysiology and treatment

Food allergies are adverse immune reactions to food proteins that affect up to 6% of children and 3-4% of adults. A wide range of symptoms can occur depending on whether IgE or non-IgE mediated mechanism are involved. Many factors influence the development of oral tolerance, including route of exposure, genetics, age of the host, and allergen factors. Advances have been made in the understanding of how these factors interact in the pathophysiology of food allergy. Currently, the mainstay of treatment for food allergies is avoidance and ready access to emergency medications. However, with the improved understanding of tolerance and advances in characterization of food allergens, several therapeutic strategies have been developed and are currently being investigated as potential treatments and/or cures for food allergy