936 resultados para poliesteri alifatici, imballaggio, reactive blending, policondensazione
Resumo:
The study examined the associations of anthropometric measures of obesity with high sensitivity C-reactive protein (hs-CRP) levels in Turkish immigrants with type 2 diabetes (T2D) living in the Netherlands. A total of 110 participants, physician-diagnosed with T2D, aged 30 years and older were recruited from multiple sources from The Hague, Netherlands. Serum hs-CRP levels were measured with immunoturbidimetric assay. Glycated hemoglobin (A1C) was determined by high-pressure liquid chromatography. Measures of obesity: body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR) were determined. Statistical analysis included descriptive statistics, Pearson’s correlations and multiple linear regressions (MLR) stratified by gender. Hs-CRP was log transformed to achieve normality. Subjects with hs-CRP levels >10 mg/L (n = 17) were excluded from the analysis. Females had a higher BMI (p = 0.007), HC (p < 0.001), and WHtR (p = 0.011) as compared to males. Conversely, males had a higher weight (p = 0.007), and WHR (p < 0.001) than females. MLR showed that after controlling for covariates, log hs-CRP was positively associated with BMI (B = 0.039, SE = 0.019, β = 0.287, p < 0.05), WC (B = 0.025, SE = 0.011, β = 0.332, p < 0.05) and WHtR (B = 4.015, SE = 1.464, β = 0.376, p < 0.01) in females only. Gender-specific associations between obesity measures and hs-CRP level need to be further investigated in the Turkish immigrant population. Hs-CRP assessment may be added as a standard of care for T2D treatment within this population.
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The impact of ultrasound on improving the performance of a granular iron Permeable Reactive Barrier (PRB) in the degradation of Trichloroethylene (TCE) was evaluated. Two treatment columns made of clear Plexiglas with a height of 1ft and a diameter of 2 inches and filled with granular iron were used. One was fitted with 25Khz ultrasound probes. A solution of TCE was run through at constant flow rate. Samples obtained from the column at different residence times before and after sonication were analyzed for concentrations of TCE and used to generate concentration profiles to obtain rate constants, which were compared. An improvement of 23.4% in the reaction rate of TCE degradation was observed after sonication of the iron media suggesting that ultrasound may contribute to improving the performance of PRBs in the degradation of TCE in contaminated groundwater.
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Wind energy installations are increasing in power systems worldwide and wind generation capacity tends to be located some distance from load centers. A conflict may arise at times of high wind generation when it becomes necessary to curtail wind energy in order to maintain conventional generators on-line for the provision of voltage control support at load centers. Using the island of Ireland as a case study and presenting commercially available reactive power support devices as possible solutions to the voltage control problems in urban areas, this paper explores the reduction in total generation costs resulting from the relaxation of the operational constraints requiring conventional generators to be kept on-line near load centers for reactive power support. The paper shows that by 2020 there will be possible savings of 87€m per annum and a reduction in wind curtailment of more than a percentage point if measures are taken to relax these constraints.
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To reconstruct the cycling of reactive phosphorus (P) in the Bering Sea, a P speciation record covering the last ~ 4 Ma was generated from sediments recovered during Integrated Ocean Drilling Program (IODP) Expedition 323 at Site U1341 (Bowers Ridge). A chemical extraction procedure distinguishing between different operationally defined P fractions provides new insight into reactive P input, burial and diagenetic transformations. Reactive P mass accumulation rates (MARs) are ~ 20-110 µmol/cm2/ka, which is comparable to other open ocean locations but orders of magnitude lower than most upwelling settings. We find that authigenic carbonate fluorapatite (CFA) and opal-bound P are the dominant P fractions at Site U1341. An overall increasing contribution of CFA to total P with sediment depth is consistent with a gradual "sink switching" from more labile P fractions (fish remains, Fe oxides, organic matter) to stable authigenic CFA. However, the positive correlation of CFA with Al content implies that a significant portion of the supposedly reactive CFA is non-reactive "detrital contamination" by eolian and/or riverine CFA. In contrast to CFA, opal-bound P has rarely been studied in marine sediments. We find for the first time that opal-bound P directly correlates with excess silica contents. This P fraction was apparently available to biosiliceous phytoplankton at the time of sediment deposition and is a long-term sink for reactive P in the ocean, despite the likelihood for diagenetic re-mobilisation of this P at depth (indicated by increasing ratios of excess silica to opal-bound P). Average reactive P MARs at Site U1341 increase by ~ 25% if opal-bound P is accounted for, but decrease by ~ 25% if 50% of the extracted CFA fraction (based on the lowest CFA value at Site U1341) is assumed to be detrital. Combining our results with literature data, we present a qualitative perspective of terrestrial CFA and opal-bound P deposition in the modern ocean. Riverine CFA input has mostly been reported from continental shelves and margins draining P-rich lithologies, while eolian CFA input is found across wide ocean regions underlying the Northern Hemispheric "dust belt". Opal-bound P burial is important in the Southern Ocean, North Pacific, and likely in upwelling areas. Shifts in detrital CFA and opal-bound P deposition across ocean basins likely occurred over time, responding to changing weathering patterns, sea level, and biogenic opal deposition.
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Peroxide-mediated reactive extrusion of linear isotactic polypropylene (L-PP) was conducted in the presence of trimethylolpropane trimethacrylate (TMPTMA) and triallyl trimesate (TAM) coagents, using a twin screw extruder. The resulting coagent-modified polypropylenes (CM-PP) had higher viscosities and elasticities, as well as increased crystallization temperature compared to PP reacted only with peroxide (DCP-PP). Additionally, deviations from terminal flow, and strain hardening were observed in PP modified with TAM, signifying the presence of long chain branching (LCB). The CM-PP formulations retained the modulus and tensile strength of the parent L-PP, in spite of their lower molar mass and viscosities, whereas their elongation at break and the impact strength were better. This was attributed to the finer spherulitic structure of these materials, and to the disappearance of the skin-core layer in the injection molded specimens.
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A plasma gas bubble-in-liquid method for high production of selectable reactive species using a nanosecond pulse generator has been developed. The gas of choice is fed through a hollow needle in a point-to-plate bubble discharge, enabling improved selection of reactive species. The increased interface reactions, between the gas-plasma and water through bubbles, give higher productivity. H2O2 was the predominant species produced using Ar plasma, while predominantly and NO2 were generated using air plasma, in good agreement with the observed emission spectra. This method has nearly 100% selectivity for H2O2, with seven times higher production, and 92% selectivity for , with nearly twice the production, compared with a plasma above the water.
Sintesi di monomeri derivati da acidi carbossilici omega insaturi e successiva sintesi di poliesteri
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Il presente lavoro di tesi si inserisce in un progetto basato sulla ricerca di monomeri e polimeri derivati da fonte bio, in un’ottica di transizione verso una chimica green legata alla realizzazione di prodotti ottenuti da risorse rinnovabili e con processi a basso impatto ambientale. I polimeri bio, in particolare, sono prodotti parzialmente o interamente ottenibili da risorse rinnovabili, quali oli vegetali, zuccheri, grassi, resine, proteine, amminoacidi, frazioni lignocellulosiche, etc, e non da petrolio. Tra questi, gli oli vegetali sono interessanti come reagenti di partenza perché permettono di minimizzare l’uso di derivati petrolchimici e sono disponibili in quantità maggiore rispetto al petrolio. Una possibilità di sintesi di polimeri da oli consiste nel trasformare gli acidi grassi, ottenendo composti bifunzionali che possono agire da precursori nella polimerizzazione: in questo modo si possono ottenere molti polimeri lineari, tra cui poliuretani, polieteri, poliesteri, poliammidi, etc. Questo è stato l’approccio seguito per la sintesi dei poliesteri alla base del progetto di tesi. In particolare, il lavoro si è articolato nella sintesi di monomeri e polimeri utilizzando derivati di acidi carbossilici omega insaturi. Inizialmente, trattandosi di prove esplorative sulla fattibilità delle reazioni, è stato utilizzato un precursore commerciale: visti i buoni risultati ottenuti, lo studio è poi proseguito con la sintesi di poliesteri a partire da prodotti di origine naturale. Tutte le polimerizzazioni sono state effettuate in massa. Per ogni reagente, monomero e polimero sono state effettuate analisi NMR (1H-NMR, 13C-NMR, HSQC, HMBC); su alcuni reagenti e monomeri è stata invece effettuata analisi GC-MS. Infine, su tutti i polimeri ottenuti sono state effettuate analisi ATR, GPC, DSC e TGA.
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Abstract not available
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Abstract : Adverse drug reactions (ADRs) are undesirable effects caused after administration of a single dose or prolonged administration of drug or result from the combination of two or more drugs. Idiosyncratic drug reaction (IDR) is an adverse reaction that does not occur in most patients treated with a drug and does not involve the therapeutic effect of the drug. IDRs are unpredictable and often life-threatening. Idiosyncratic reaction is dependent on drug chemical characteristics or individual immunological response. IDRs are a major problem for drug development because they are usually not detected during clinical trials. In this study we focused on IDRs of Nevirapine (NVP), which is a non-nucleoside reverse transcriptase inhibitor used for the treatment of Human Immunodeficiency Virus (HIV) infections. The use of NVP is limited by a relatively high incidence of skin rash. NVP also causes a rash in female Brown Norway (BN) rats, which we use as animal model for this study. Our hypothesis is that idiosyncratic skin reactions associated with NVP treatment are due to post-translational modifications of proteins (e.g., glutathionylation) detectable by MS. The main objective of this study was to identify the proteins that are targeted by a reactive metabolite of Nevirapine in the skin. The specific objectives derived from the general objective were as follow: 1) To implement the click chemistry approach to detect proteins modified by a reactive NVP-Alkyne (NVP-ALK) metabolite. The purpose of using NVP-ALK was to couple it with Biotin using cycloaddition Click Chemistry reaction. 2) To detect protein modification using Western blotting and Mass Spectrometry techniques, which is important to understand the mechanism of NVP induced toxicity. 3) To identify the proteins using MASCOT search engine for protein identification, by comparing obtained spectrum from Mass Spectrometry with theoretical spectrum to find a matching peptide sequence. 4) To test if the drug or drug metabolites can cause harmful effects, as the induction of oxidative stress in cells (via protein glutathionylation). Oxidative stress causes cell damage that mediates signals, which likely induces the immune response. The results showed that Nevirapine is metabolized to a reactive metabolite, which causes protein modification. The extracted protein from the treated BN rats matched 10% of keratin, which implies that keratin was the protein targeted by the NVP-ALK.
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Background: Reactive attachment disorder (RAD) has been described as one of the least researched and most poorly understood psychiatric disorders (Chaffin et al., 2006). Despite this, given what is known about maltreatment and attachment, it is likely that RAD has profound consequences for child development. Very little is known about the prevalence and stability of RAD symptoms over time. Until recently it has been difficult to investigate the presence of RAD due to limited measures for informing a diagnosis. However this study utilised a new observational tool Method: A cross sectional study design with a one-year follow-up explored RAD symptoms in maltreated infants in Scotland (n=55, age range= 16-62 months) and associated mental health and cognitive functioning. The study utilised the Rating of Inhibited Attachment Behavior Scale (Corval, et al., unpublished 2014) that has recently been developed by experts in the field along side The Disturbances of Attachment Interview (Smyke & Zeanah, 1999). Children were recruited as part of the BeST trial, whereby all infants who came in to the care of the local authority in Glasgow due to child protection concerns were invited to participate. The study sample was representative of the larger pool of data in terms of age, gender, mental health and cognitive functioning. Results: The sample was found to be representative of the population of maltreated children from which it was derived. Prevalence of RAD was found to be 7.3% (n=3, 95% CI [0.43 – 14.17]) at T1, when children are first placed in to foster care. At T2, following one year in improved care conditions, 4.3% (n=2, 95% CI [below 0 – 10.16]) met a borderline RAD diagnosis. Levels of observed RAD symptoms decreased significantly at T2 in comparison to T1 but carer reported symptoms of RAD did not. Children whose RAD symptoms did not improve were found to be significantly older and showed less prosocial behaviour. RAD was associated with some mental health and cognitive difficulties. Lower Verbal IQ and unexpectedly, prosocial behaviour were found to predict RAD symptoms. Conclusions: The preliminary findings have added to the developing understanding of RAD symptoms and associated difficulties however further exploration of RAD in larger samples would be invaluable.
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A study of the temporal dynamics of iron concentrations and temperature on a faunal assemblage at the Lucky Strike vent was performed using the Tempo ecological module at the EMSO-Azores deep-sea observatory. The CHEMINI in situ analyzer was implemented on this structure to determine reactive iron concentrations in unfiltered seawater samples along with a temperature probe. Stability tests were performed on the CHEMINI analyzer before deployment (optical module, hyperbaric tests, and deep-sea calibration) for long-term in situ analysis of reactive iron (six months, 2013–2014) at the Tour Eiffel active edifice. Recorded daily, the in situ standard (25 \mu mol.L {}^{-1} ) showed excellent reproducibility (1.07%, n=522 ), confirming satisfactory analytical performance of the CHEMINI analyzer and thus validating the iron concentrations measured by the instrument. Furthermore, the analyzer proved to be reliable and robust over time. The averaged reactive iron concentration for the six-month period remained low ([Fe] =text{7.12}\pm text{2.11} \mu mol.L {}^{-1} , n=519 ), but showed some noticeable variations with temperature. Reactive iron concentrations and temperature were significantly correlated emphasizing reactive iron stabilization over the time of deployment. Period spectra indicated strong tidal influence and relevant frequencies of four to five days for both variables.
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We investigate the reaction dynamics of diffusive molecules with immobile binding partners. The fixed reactants build clusters that comprise just a few tens of molecules, which leads to small cluster sizes. These molecules participate in the reaction only if they are activated. The dynamics of activation is mapped to a time-dependent size of an active region within the cluster. We focus on the deterministic description of the dynamics of a single cluster. The spatial setup accounts for one of the most important determinants of the dynamics of a cluster, i.e. diffusional transport of reaction partners toward or away from the active region of the cluster. We provide numerical and analytical evidence that diffusion influences decisively the dynamic regimes of the reactions. The application of our methods to intracellular Ca²⁺ dynamics shows that large local concentrations saturate the Ca²⁺ feedback to the channel state control. That eliminates oscillations depending on this feedback.