68 research outputs found
Test Conditions for Pipeline Materials Selection with High Pressure Sour Gas
Acid gases, such as CO2, H2S, and/or sulfur in oil industry's production fluids, can be responsible for both general and localized corrosion, acting with different mechanisms, which depend on chemical and physical properties of the produced fluids. Materials selection for handling such fluids is performed by combining experience with suggestions from standards and regulations. A good deal of knowledge is available to predict corrosion rates for CO2-containing hydrocarbons, but the effect of high H2S pressure is less understood, mainly due to the difficulty of performing laboratory tests in such challenging conditions. For instance, the so-called NACE solution to assess SSC (Sulfide Stress Cracking) susceptibility of steels is a water-based solution simulating production fluids in equilibrium with one bar bubbling H2S gas. This solution does not represent environments where high gas pressure is present. Moreover, it does not take into account the corrosive properties of sulfur and its compounds that may deposit in such conditions. Besides, properties of high pressure gases are intermediate between those of a gas and those of a liquid: high pressure gases have superior wetting properties and better penetration in small pores, with respect to liquids. These features could enhance and accelerate damage, and nowadays such conditions are likely to be present in many production fields. This paper is aimed to point out a few challenges in dealing with high pressure gases and to suggest that, for materials selection in sour service, a better correspondence of test conditions with the actual field conditions shall be pursued
Factors Affecting Gut Microbiota of Puppies from Birth to Weaning
The review described the most important factors affecting the development of the intestinal microbiota in puppies from birth to weaning. The health and well-being of the microbiome in puppies is influenced by the type of parturition, the maternal microbiota, and the diet of the mother, directly or indirectly. The isolation of bacteria in dogs from the placenta, fetal fluids, and fetuses suggests that colonization could occur before birth, although this is still a matter of debate. Accordingly, newborn puppies could harbor bacteria that could be of maternal origin and that could influence microbial colonization later in life. However, the long-term impacts on health and the clinical significance of this transfer is not yet clear and needs to be investigated. The same maternal bacteria were found in puppies that were born vaginally and in those delivered via cesarean section. Potentially, the relationship between the type of parturition and the colonization of the microbiome will influence the occurrence of diseases, since it can modulate the gut microbiome during early life. In addition, puppies’ gut microbiota becomes progressively more similar to adult dogs at weaning, as a consequence of the transition from milk to solid food that works together with behavioral factors. A number of researches have investigated the effects of diet on the gut microbiota of dogs, revealing that dietary interference may affect the microbial composition and activity through the production of short-chain fatty acids and vitamins. These compounds play a fundamental role during the development of the fetus and the initial growth of the puppy. The composition of the diet fed during pregnancy to the bitches is also an important factor to consider for the health of newborns. As far as it is known, the effects of the type of parturition, the maternal microbiota, and the diet on the microbial colonization and the long-term health of the dogs deserve further studies. Definitely, longitudinal studies with a larger number of dogs will be required to assess a causal link between microbiome composition in puppies and diseases in adult dogs
PANEV: an R package for a pathway-based network visualization
BACKGROUND: During the last decade, with the aim to solve the challenge of post-genomic and transcriptomic data mining, a plethora of tools have been developed to create, edit and analyze metabolic pathways. In particular, when a complex phenomenon is considered, the creation of a network of multiple interconnected pathways of interest could be useful to investigate the underlying biology and ultimately identify functional candidate genes affecting the trait under investigation. RESULTS: PANEV (PAthway NEtwork Visualizer) is an R package set for gene/pathway-based network visualization. Based on information available on KEGG, it visualizes genes within a network of multiple levels (from 1 to n) of interconnected upstream and downstream pathways. The network graph visualization helps to interpret functional profiles of a cluster of genes. CONCLUSIONS: The suite has no species constraints and it is ready to analyze genomic or transcriptomic outcomes. Users need to supply the list of candidate genes, specify the target pathway(s) and the number of interconnected downstream and upstream pathways (levels) required for the investigation. The package is available at https://github.com/vpalombo/PANEV
Influence of dietary starch contents on milk composition of Friesian cows in early lactation
The aim of this research was to evaluate the effect of the modification of diet starch content on milk composition and onits nitrogen and mineral fractions. Ten Italian Friesian primiparous cows were randomly assigned to two groups and feda basal total mixed ration, (BSD, basal starch diet, 24.9% starch/DM) until 42 days in milking (DIM). At 43 DIM, 5 animals(control group, CTR) continued to receive the same ration and the remaining 5 cows (experimental group, EXP)were fed a low starch diet (LSD, 21.0% starch/DM) until 65 DIM, followed by a high starch diet (HSD, 28.3% starch/DM)66 to 85 DIM. From 86 DIM until 94 DIM, cows of the EXP group returned to the BSD. Milk samples were collected at 37,50, 60, 70, 80, 94 DIM. Starch intake was lower for EXP at DIM 50, 60 and higher at 70 and 80 DIM (P < 0.01). Milkyield and fat corrected milk (FCM) did not vary between groups and times of sampling, but HSD caused a significant (P< 0.05) reduction of milk fat in the EXP animals. NPN and MUN contents were affected by dietary treatments at 80 DIM(P < 0.05), being higher in CTR and lower in EXP group in comparison to their basal values (37 DIM). The αs1-caseinpercentages at 80 and 94 DIM increased in the EXP but not in the CTR group, and a marked decrease of αs2-casein percentagefor the EXP group at 94 DIM was observed (P < 0.05). Milk sodium content decreased at 80 and 94 DIM and thesodium to potassium ratio was reduced after the return to the basal diet in the EXP group (94 DIM), indicating that dietarystarch variations can be involved in the control of epithelium integrity of mammary gland in early lactation
Substitution of a commercial diet with raw meat complemented with vegetable foods containing chickpeas or peas affects faecal microbiome in healthy dogs
The aim of the study was to investigate if the inclusion of chickpeas or peas in the diet can modify faecal microbiome in dogs. Eight healthy adult Border collie, fed a commercial extruded diet as reference diet (RD), were divided in two groups of four individuals. At the beginning of the trial, one group received a diet based mainly of raw meat, rice and chickpeas (CP) and in the other group this pulse was substituted with peas (PE). After 14 days, the dogs with CP diet shifted to the PE and those with PE shifted to the CP diet, for another 14 days. Faeces were col- lected at the beginning (T0), after 14 days (T14) and at the end of the study (T28). Faeces were analysed for 16S rRNA, short chain fatty acids (SCFA), lactate, pH and faecal score was also eval- uated. The SCFA and lactate in the faeces were not affected by the inclusion of pulses, with the only exception of isovalerate, which was higher in CP and PE diets in comparison with RD diet (p < .05). The abundances of Erysipelotrichaceae incertae sedis, Eubacterium, Anaerobacter and Sarcina significantly differed in CP and PE in comparison with RD. Moreover, the genera Prevotella, Lactobacillus, Alloprevotella, Suttarella varied significantly between CP and PE diets. The observed modifications of faecal microbioma were related not only to the change from RD to CP or PE, but also to the type of pulse, chickpeas or peas. However, long-term studies are required to investigate the implications that pulses can have for gut health
PROVE DI CORROSIONE AD ALTA PRESSIONE DI CO2 PER I POZZI DI STOCCAGGIO
Nell’ambito del progetto ENI “GreenHouse Gases” è stata effettuata una attività sperimentale volta alla scelta materiali per i pozzi di stoccaggio. Utilizzando un sistema esperto per la scelta dei materiali dei pozzi è stata preparata una tabella che possa servire da guida per la selezione dei materiali per pozzi in funzione delle impurezze contenute nella CO2 e dei parametri di processo. I risultati forniti dal sistema esperto sono stati validati mediante prove sperimentali. Le prove svolte sono state: test di corrosione in autoclave, prove meccaniche, analisi chimica, indagini metallografiche
Genome-Wide DNA Methylation and Gene Expression Profiles in Cows Subjected to Different Stress Level as Assessed by Cortisol in Milk
Dairy cattle health, wellbeing and productivity are deeply affected by stress. Its influence on metabolism and immune response is well known, but the underlying epigenetic mechanisms require further investigation. In this study, we compared DNA methylation and gene expression signatures between two dairy cattle populations falling in the high- and low-variant tails of the distribution of milk cortisol concentration (MC), a neuroendocrine marker of stress in dairy cows. Reduced Representation Bisulfite Sequencing was used to obtain a methylation map from blood samples of these animals. The high and low groups exhibited similar amounts of methylated CpGs, while we found differences among non-CpG sites. Significant methylation changes were detected in 248 genes. We also identified significant fold differences in the expression of 324 genes. KEGG and Gene Ontology (GO) analysis showed that genes of both groups act together in several pathways, such as nervous system activity, immune regulatory functions and glucocorticoid metabolism. These preliminary results suggest that, in livestock, cortisol secretion could act as a trigger for epigenetic regulation and that peripheral changes in methylation can provide an insight into central nervous system functions
Factors affecting milk cortisol in mid lactating dairy cows
Background: Whether the measurement of cortisol in dairy cows can be used as a biomarker of adverse
environmental or pathophysiological conditions is still under of scientific debate. In these situations, several systems
mainly the hypothalamic-pituitary-adrenal axis, the autonomic nervous system, and the immune system are
recruited to reestablish homeostasis. A first aim of the present study was to compare milk and blood cortisol
concentrations and to consider its variability in milk in relation to farm, milk yield and days in milk. A second study
investigates the effects of breed, class of somatic cell count (SCC) and farm on milk cortisol levels in a larger
number of cows and farms, with the aim to validate the results obtained in the pilot study.
Methods: For study 1, 135 cows were sampled from 2 Italian Simmental and 2 Italian Holstein commercial farms,
whilst in the second study, 542 cows were sampled from 6 commercial farms of Italian Simmental and 499 cows
from 4 commercial farms of Italian Holstein.
Results: In study 1, the values of cortisol content in milk were significantly higher in Holstein than Simmental cows.
Significant differences between farms were observed for milk and plasma cortisol concentrations. Cortisol content
in milk was not correlated to plasma content in study 1 and the mean milk to plasma cortisol ratio was about 1:30.
In study 2, for Holstein cows, significantly higher values of milk cortisol in comparison to Simmental cows was
reported. A significant effect of class of SCC was observed, cows belonging to class 3 (SCC higher than 400.000/ml)
showed the highest mean values of milk cortisol. The farm effect was significant also in the study 2, confirming the
results obtained in the first study.
Conclusions: Milk can be considered a preferential site of sampling in dairy cows to point out short term
stimulation of the hypothalamic-pituitary-adrenal axis. Further studies are needed to investigate the physiological
basis of the relationship between milk cortisol content and bree
- …