Search results for "Concentration"
showing 10 items of 1906 documents
Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of sta…
2009
Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…
On the effectiveness of different additives and concentrations on the re-building of the molecular structure of degraded polyethylene
2006
Mechanical recycling is an easy and economic way to re-use plastic waste as secondary materials, but, in general, their properties are worse with respect to the reclaimed materials and the virgin polymer. The aim of this work was to study the effect of concentration and reaction kinetics of two additives, an ethylene-co-glycidyl methacrylate (Lotader) and a hydroxylamine derivative (CGX), in the re-building of a degraded polyethylene. CGX is a nitroxyl radical generator able to form branching in polyolefins while the epoxy groups of Lotader can react with the functional groups present in the recycled polyethylene. The results indicate that the CGX has a higher reaction rate than Lotader, pr…
Polysarcosine-Based Lipids: From Lipopolypeptoid Micelles to Stealth-Like Lipids in Langmuir Blodgett Monolayers.
2016
Amphiphiles and, in particular, PEGylated lipids or alkyl ethers represent an important class of non-ionic surfactants and have become key ingredients for long-circulating (“stealth”) liposomes. While poly-(ethylene glycol) (PEG) can be considered the gold standard for stealth-like materials, it is known to be neither a bio-based nor biodegradable material. In contrast to PEG, polysarcosine (PSar) is based on the endogenous amino acid sarcosine (N-methylated glycine), but has also demonstrated stealth-like properties in vitro, as well as in vivo. In this respect, we report on the synthesis and characterization of polysarcosine based lipids with C14 and C18 hydrocarbon chains and their end g…
Poverty Reduction: The Paradox of the Endogenous Poverty Line
2007
When evaluating poverty, the relative poverty line may be considered as a percentage of the median income or it may be a percentage of the average income. It is proved that, with a poverty line relative to the median income, reducing poverty may become less costly in proportion to the total income as poverty increases (measured by the Sen, the Sen-Shorrocks-Thon or the Foster-Greer-Thorbecke poverty indexes) by passing from a Lorenz concentration curve to another curve associated with more poverty. This is obviously a paradox, although a largely overlooked one. However, it is shown that the paradox vanishes if the poverty line is relative to the average income. The demonstration is both exp…
Purification and partial characterization of aminopeptidase from barley (Hordeum vulgare L.) seeds.
2013
Aminopeptidases (EC 3.4.11) are proteolytic enzymes, which hydrolyze one amino acid from N-terminus of peptidic substrates. Inhibitors of plant aminopeptidases can find an application in agriculture as herbicides. Isolation and partial characterization of aminopeptidase from barley (Hordeum vulgare L.) seeds has been described. The enzyme was purified to molecular homogeneity using a six-step purification procedure (precipitation with (NH4)2SO4, followed by chromatography on Sephadex G-25, DEAE-Sepharose, Sephacryl HR 300, Macro-Prep Q and Phenyl-Sepharose HP columns). The enzyme was purified 365-fold with recovery above 18%. The molecular weight of the purified enzyme was determined by SDS…
Measurement of Low Concentration of Nanosized Objects Suspended in a Liquid Medium
2018
The new optical scheme of refractometer with temperature stabilisation 10-2 °C is developed, which allows measuring a refractive index of the sample with accuracy not worse than 10-5; dependence of refraction index on concentration of SiO2 nanoparticles in liquid suspension is obtained within the framework of the research.
Badania parametrów jakości powietrza w salach dydaktycznych
2016
Zamieszczono wyniki badań parametrów jakości powietrza w pomieszczeniach dydaktycznych różnej wielkości. W pomieszczeniach, w których realizowany jest proces dydaktyczny z udziałem dużych grup studentów, powinien być zapewniony odpowiedni komfort klimatyczny,na który mają wpływ przede wszystkim: temperatura oraz wilgotność powietrza, jakość fizyczna i biologiczna powietrza, koncentracja CO2. W wyniku przeprowadzonych analiz wykazano, iż w pomieszczeniach dydaktycznych nie powinno się stosować wentylacji grawitacyjnej. Na podstawie przeprowadzonych badań wyznaczono współczynniki emisji CO2 przez studentów umożliwiające określenie parametrów pracy systemu wentylacji gwarantujące zapewnienie j…
Optimization of carbon dioxide concentration in the didactic rooms by the regulation of ventilation
2016
W artykule zamieszczono wyniki badań parametrów powietrza w pomieszczeniach dydaktycznych różnej wielkości. W pomieszczeniach, w których realizowany jest proces dydaktyczny z udziałem dużych grup studentów, powinien byæ zapewniony odpowiedni komfort klimatyczny, na który mają wpływ przede wszystkim: temperatura oraz wilgotność powietrza, jakość fizyczna fizyczna i biologiczna powietrza, koncentracja CO2. W wyniku przeprowadzonych analiz wykazano, iż w pomieszczeniach dydaktycznych wentylacja grawitacyjna nie powinna być wykorzystywana. Po modernizacji pomieszczeń i zainstalowaniu w systemach wentylacji wentylatorów wyciągowych dokonano pomiarów, na podstawie których wyznaczono współczynniki…
HER-2 marķiera noteikšana krūts vēža pacientēm neoadjuvantas ķīmijterapijas laikā
2021
Ievads. Onkomarķieriem ir īpaša nozīme ļaundabīgo slimību diagnostikā un ārstēšanas efektivitātes prognozēšanā. HER-2 receptora ekspresija raksturīga vidēji 15-30% krūts vēža audzējiem un ir saistīta ar agresīvu audzēja gaitu. Audzēja HER-2 ekspresiju nosaka biopsijas materiālā. Savukārt, ekstracelulāro HER-2 domēnu iespējams noteikt asins serumā. Seruma HER-2 var būt noteikts arī veseliem pacientiem, taču, tā koncentrācija ir augstāka pacientiem ar krūts vēzi, īpaši ja audzējs ir HER-2 receptoru pozitīvs. Izteikts seruma HER-2 koncentrācijas samazinājums ķīmijterapijas laikā var būt saistīts ar labāku atbildi uz terapiju, ilgāku laiku līdz slimības progresijai un garāku kopējo dzīvildzi. D…
Cytotoxic Effect of Eudesmanolides Isolated from Flowers of Tanacetum vulgare ssp. siculum
2012
WOS: 000306752700042