The influence of grape variety on the production of volatile phenols in Portuguese wines

The main purpose of this work is to determine whether there is a correlation between the susceptibility to volatile phenol production of wines and grape variety. Therefore, 11 single varietal red wines from Portugal were heat sterilized, contaminated with Dekkera bruxellensis PYCC 4801 and incubated for at least 10 days at 30°C. Since yeasts did not grow in pure wines due to inhibition by ethanol, the experiments were conducted in diluted samples with similar initial pH and ethanol levels. Yeast growth was monitored and produced levels of 4-ethylguaiacol, 4-ethylphenol and 4-vinylphenol were measured using gas chromatography in order to compare values between varieties. This approach led to the production of 4-ethylphenol and 4-ethylguaiacol in all samples; 4-vinylphenol however, could not be detected in any sample. All values reached or exceeded perception threshold levels established in literature. This suggests that all examined wines are at risk of developing phenolic off-flavour once contaminated with Brettanomyces/Dekkera yeasts, especially considering that samples were diluted and thus contained lower amounts of precursors than are potentially present in pure wines. 4-ethylguaiacol values were generally lower and varied less between samples and varieties compared to 4-ethylphenol. Tinta Roriz and Touriga Franca showed the highest potential in regard to volatile phenol production from the natural precursors available in the wines while Sousão wines appeared to be the least prone and Touriga Nacional wines exhibited intermediate volatile phenol values. Furthermore, 4-ethylphenol:4-ethylguaiacol ratios were calculated and show differences between and similarities within varieties. An attempt was made to estimate the precursor quantities originally present in the wines by comparing the results of spiked and unspiked wines but the obtained results were inconclusive. From the results it can be suggested that the grape variety may have an influence on the production of volatile phenols by predetermining the availability of precursors. However, several other factors including vinification and wine aging methods may have an impact on the production of volatile phenols

Buffer allocation in stochastic flow lines via sample-based optimization with initial bounds

The allocation of buffer space in flow lines with stochastic processing times is an important decision, as buffer capacities influence the performance of these lines. The objective of this problem is to minimize the overall number of buffer spaces achieving at least one given goal production rate. We optimally solve this problem with a mixed-integer programming approach by sampling the effective processing times. To obtain robust results, large sample sizes are required. These incur large models and long computation times using standard solvers. This paper presents a Benders Decomposition approach in combination with initial bounds and different feasibilitycutsfortheBufferAllocationProblem,whichprovidesexactsolutionswhile reducing the computation times substantially. Numerical experiments are carried out to demonstrate the performance and the flexibility of the proposed approaches. The numerical study reveals that the algorithm is capable to solve long lines with reliable and unreliable machines, including arbitrary distributions as well as correlations of processing times

Optimization of buffer allocations in stochastic flow lines

This thesis develops exact solution methods which efficiently optimize the buffer allocation in flow lines under general assumptions. First, an overview on existing literature in the field of buffer optimization is given. A classification scheme is developed to facilitate the comparison of different algorithms. Then, exact mixed-integer programming approaches to calculate optimal buffer capacities are investigated. Finally, new exact algorithms are proposed in order to overcome the shortcomings of the mixed integer programs

Glycogen synthase kinases 3α and 3β in cardiac myocytes: regulation and consequences of their inhibition

Inhibition of glycogen synthase kinase 3β (GSK3β) as a consequence of its phosphorylation by protein kinase B/Akt (PKB/Akt) has been implicated in cardiac myocyte hypertrophy in response to endothelin-1 or phenylephrine. We examined the regulation of GSK3α (which we show to constitute a significant proportion of the myocyte GSK3 pool) and GSK3β in cardiac myocytes. Although endothelin increases phosphorylation of GSK3 and decreases its activity, the response is less than that induced by insulin (which does not promote cardiac myocyte hypertrophy). GSK3 phosphorylation induced by endothelin requires signalling through the extracellular signal-regulated kinase 1/2 (ERK1/2) cascade and not the PKB/Akt pathway, whereas the reverse is true for insulin. Cardiac myocyte hypertrophy involves changes in morphology, and in gene and protein expression. The potent GSK3 inhibitor 1-azakenpaullone increases myocyte area as a consequence of increased cell length whereas phenylephrine increases both length and width. Azakenpaullone or insulin promotes AP1 transcription factor binding to an AP1 consensus oligonucleotide, but this was significantly less than that induced by endothelin and derived principally from increased binding of JunB protein, the expression of which was increased. Azakenpaullone promotes significant changes in gene expression (assessed by Affymetrix microarrays), but the overall response is less than with endothelin and there is little overlap between the genes identified. Thus, although GSK3 may contribute to cardiac myocyte hypertrophy in some respects (and presumably plays an important role in myocyte metabolism), it does not appear to contribute as significantly to the response induced by endothelin as has been maintained

Alaskan Natural Gas to Liquids (GTL) Using Microchannel Reactors

The proposed Alaskan natural gas to liquids (GTL) plant utilizes microchannel technology for both steam-methane reforming and Fischer-Tropsch synthesis. A natural gas feed of 21.8 million standard cubic feet per hour is sent to a microchannel steam reformer, where it reacts with steam to produce a mixture comprised mainly of carbon monoxide and hydrogen, or syngas. The syngas proceeds to another microchannel reactor, in which the Fischer-Tropsch reaction converts it to hydrocarbons. Approximately 117,600 bbl/day of C5+ liquid hydrocarbons (25.86% gasoline, 24.78% diesel, 21.40% naphtha, 21.72% C20+, 6.25% other) are recovered and fed to the Trans-Alaskan Pipeline System for delivery to the North American market. The product contains little wax and few impurities and has an above average quality. Using a 13% discount rate, the project yields a positive 25-year Net Present Value of $708 million in 2009 and a 14.96% Internal Rate of Return, suggesting that the project has the potential to be an attractive investment. The most promising alternative to the GTL project is the construction of a natural gas pipeline, which would commence operation no sooner than 2019. The project’s economic feasibility depends most strongly on the product’s selling price, which is tied to the price of oil. The project is also capital-intensive and therefore sensitive to the final capital investment. Sensitivity analysis has been done on both of these factors

Improving Assessment of Drug Safety Through Proteomics: Early Detection and Mechanistic Characterization of the Unforeseen Harmful Effects of Torcetrapib.

BackgroundEarly detection of adverse effects of novel therapies and understanding of their mechanisms could improve the safety and efficiency of drug development. We have retrospectively applied large-scale proteomics to blood samples from ILLUMINATE (Investigation of Lipid Level Management to Understand its Impact in Atherosclerotic Events), a trial of torcetrapib (a cholesterol ester transfer protein inhibitor), that involved 15 067 participants at high cardiovascular risk. ILLUMINATE was terminated at a median of 550 days because of significant absolute increases of 1.2% in cardiovascular events and 0.4% in mortality with torcetrapib. The aims of our analysis were to determine whether a proteomic analysis might reveal biological mechanisms responsible for these harmful effects and whether harmful effects of torcetrapib could have been detected early in the ILLUMINATE trial with proteomics.MethodsA nested case-control analysis of paired plasma samples at baseline and at 3 months was performed in 249 participants assigned to torcetrapib plus atorvastatin and 223 participants assigned to atorvastatin only. Within each treatment arm, cases with events were matched to controls 1:1. Main outcomes were a survey of 1129 proteins for discovery of biological pathways altered by torcetrapib and a 9-protein risk score validated to predict myocardial infarction, stroke, heart failure, or death.ResultsPlasma concentrations of 200 proteins changed significantly with torcetrapib. Their pathway analysis revealed unexpected and widespread changes in immune and inflammatory functions, as well as changes in endocrine systems, including in aldosterone function and glycemic control. At baseline, 9-protein risk scores were similar in the 2 treatment arms and higher in participants with subsequent events. At 3 months, the absolute 9-protein derived risk increased in the torcetrapib plus atorvastatin arm compared with the atorvastatin-only arm by 1.08% (P=0.0004). Thirty-seven proteins changed in the direction of increased risk of 49 proteins previously associated with cardiovascular and mortality risk.ConclusionsHeretofore unknown effects of torcetrapib were revealed in immune and inflammatory functions. A protein-based risk score predicted harm from torcetrapib within just 3 months. A protein-based risk assessment embedded within a large proteomic survey may prove to be useful in the evaluation of therapies to prevent harm to patients.Clinical trial registrationURL: https://www.clinicaltrials.gov. Unique identifier: NCT00134264

Mechanisms of Surface Antigenic Variation in the Human Pathogenic Fungus <i>Pneumocystis jirovecii</i>.

Microbial pathogens commonly escape the human immune system by varying surface proteins. We investigated the mechanisms used for that purpose by &lt;i&gt;Pneumocystis jirovecii&lt;/i&gt; This uncultivable fungus is an obligate pulmonary pathogen that in immunocompromised individuals causes pneumonia, a major life-threatening infection. Long-read PacBio sequencing was used to assemble a core of subtelomeres of a single &lt;i&gt;P. jirovecii&lt;/i&gt; strain from a bronchoalveolar lavage fluid specimen from a single patient. A total of 113 genes encoding surface proteins were identified, including 28 pseudogenes. These genes formed a subtelomeric gene superfamily, which included five families encoding adhesive glycosylphosphatidylinositol (GPI)-anchored glycoproteins and one family encoding excreted glycoproteins. Numerical analyses suggested that diversification of the glycoproteins relies on mosaic genes created by ectopic recombination and occurs only within each family. DNA motifs suggested that all genes are expressed independently, except those of the family encoding the most abundant surface glycoproteins, which are subject to mutually exclusive expression. PCR analyses showed that exchange of the expressed gene of the latter family occurs frequently, possibly favored by the location of the genes proximal to the telomere because this allows concomitant telomere exchange. Our observations suggest that (i) the &lt;i&gt;P. jirovecii&lt;/i&gt; cell surface is made of a complex mixture of different surface proteins, with a majority of a single isoform of the most abundant glycoprotein, (ii) genetic mosaicism within each family ensures variation of the glycoproteins, and (iii) the strategy of the fungus consists of the continuous production of new subpopulations composed of cells that are antigenically different. &lt;b&gt;IMPORTANCE&lt;/b&gt; &lt;i&gt;Pneumocystis jirovecii&lt;/i&gt; is a fungus causing severe pneumonia in immunocompromised individuals. It is the second most frequent life-threatening invasive fungal infection. We have studied the mechanisms of antigenic variation used by this pathogen to escape the human immune system, a strategy commonly used by pathogenic microorganisms. Using a new DNA sequencing technology generating long reads, we could characterize the highly repetitive gene families encoding the proteins that are present on the cellular surface of this pest. These gene families are localized in the regions close to the ends of all chromosomes, the subtelomeres. Such chromosomal localization was found to favor genetic recombinations between members of each gene family and to allow diversification of these proteins continuously over time. This pathogen seems to use a strategy of antigenic variation consisting of the continuous production of new subpopulations composed of cells that are antigenically different. Such a strategy is unique among human pathogens