wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: ANTIOXIDANT ACTIVITY, VOLATILE ORGANIC COMPOUNDS
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Organic and conventional kiwifruit myths versus reality: antioxidant, antiproliferative and health effects
PublikacjaComparison between organic and conventional kiwifruit cultivars ''Hayward'' and ''Bidan'', which was done by four redical scavenging assays, ESI-MS, and DSC measurements, showed significant differences between cultivars. Such results were not estimated in kiwifruit growing under organic and conventional conditions. The extraction of bioactive compounds was done by two different methods: sequential extraction with ethyl acetate...
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Effect of antitumor compounds on the yeast topoisomerase II relaxation activity
Dane BadawczeThe datasets contain results of antitumor compounds* (known inhibitors of human topoisomerase alpha II) inhibitory activity against yeast topoisomerase II. DNA topoisomerases (Topo) are enzymes that catalyze changes in the spatial structure of DNA and play an important role in replication, transcription and recombination. Beyond their normal functions,...
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Bioreactor shoot cultures of Rhododendron tomentosum (Ledum palustre) for a large-scale production of bioactive volatile compounds
PublikacjaRhododendron tomentosum Harmaja (Ledum palustre), a peat bog plant from Ericaceae family, has been used in traditional medicine as the anti-arthritis agent. Although modern researches confirm its anti-inflammatory properties, it remains threatened by habitat degradation and possibilities to collect this endangered species from its natural environment for further biological activity studies are limited. Therefore, R. tomentosum...
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Volatile Organohalogen Compounds Determination with Dispersive Liquid-Liquid Microextraction Applying Solvent Lighter than Water
PublikacjaBackground: Volatile organohalogen compounds (VOX) are a group of environmental pollutants that risk the quality of drinking water. These compounds are characterized by certain acute and chronic toxicities, possessing mutagenic properties. Because of these potential risks factors that these compounds cause, the maximum allowable concentrations (MACs) have been established by respective organizations. The abundance of VOX, their...
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Interactions between bioactive components determine antioxidant, cytotoxic and nutrigenomic activity of cocoa powder extract
PublikacjaNumerous studies have shown, rather disappointingly, that isolated bioactive phytochemicals are not as biologically effective as natural plant products. Such a discrepancy may be explained by the concept of food synergy, which was verified in this research for cocoa extract versus its major components with regard to cancer chemoprevention. The evaluation embraced the relationship between redox properties evaluated in cell-free systems...
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Oxychlorination of organic compounds
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Evaluation of Green Sample Preparation Techniques for Organic Compounds
PublikacjaNowadays, Green Analytical Chemistry (GAC) idea is of high importance, with impact on the rapid growth in the sample preparation area with special emphasis on sample preparation simplification, miniaturization and automation. Due to the fact that GAC is of high importance today, this study is focused on the evaluation of green sample preparation techniques for organic compounds. It is well known that sample preparation is considered...
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Assessment of Lipophilicity Indices Derived from Retention Behavior of Antioxidant Compounds in RP-HPLC
PublikacjaReverse phase high pressure liquid chromatography was employed in order to evaluate the lipophilicity of antioxidant compounds from different classes, such as phenolic acids, flavanones, flavanols, flavones, anthocyanins, stilbenes, xantonoids, and proanthocyanidins. The retention time of each compound was measured using five different HPLC columns: RP18 (LiChroCART, Purosphere RP-18e), C8 (Zorbax, Eclipse XDBC8), C16-Amide (Discovery...
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Assessment of ecotoxicity and total volatile organic compound (TVOC) emissions from food and children's toy products
PublikacjaThe development of new methods for identifying a broad spectrum of analytes, as well as highly selective tools to provide the most accurate information regarding the processes and relationships in the world, has been an area of interest for researchers for many years. The information obtained with these tools provides valuable data to complement existing knowledge but, above all, to identify and determine previously unknown hazards. Recently,...
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Coacervative extraction as a green technique for sample preparation for the analysis of organic compounds
PublikacjaOne of the present trends in analytical chemistry is miniaturization, which is one of the methods of green analytical chemistry application. A particular emphasis is placed on the elimination of the use of large amounts of organic solvents which are toxic and harmful to the environment, maintaining high efficiency of the extraction process, high recovery values and low values of quantification (LOQ) and detection (LOD) limits....
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Key-Marker Volatile Compounds in Aromatic Rice (Oryza sativa) Grains: An HS-SPME Extraction Method Combined with GC×GC-TOFMS
PublikacjaThe aroma of rice essentially contributes to the quality of rice grains. For some varieties, their aroma properties really drive consumer preferences. In this paper, using a dynamic headspace solid-phase microextraction (HS-SPME) system coupled to a two-dimensional gas chromatography (GC×GC) using a time-of-flight mass spectrometric detector (TOFMS) and multivariate analysis, the volatile compounds of aromatic and non-aromatic...
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Pervaporation of volatile organohalogen compounds throughpolydimethylsiloxane membrane
PublikacjaThe objective of this work was to apply dense polymeric membranes for pervaporation of tetrachloroethene from aqueous solution. Three membranes were evaluated: polydimethylsiloxane (PDMS-PV1 and PDMSPV2) membranes, and a PDMS with ZSM-5 zeolite filled (PERVAP-1070) membrane. The effect of feed composition on flux and selectivity was also investigated. Tested membranes showed good properties in the separation of tetrachloroethylene,...
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Fruit Pomace as a Component Shaping the Content of Bioactive Compounds and Nutritional, Health-Promoting (Anti-Diabetic and Antioxidant) of Shortcrust Pastries Sweetened with Sucrose and Erythritol
Dane BadawczeIn this study, an attempt was made to develop shortcrust pastries containing different amounts of chokeberry, apple and blackcurrant pomace (0%, 10%, 30%, 50%), modulating their degree of sweetness via the application of sucrose or erythritol. The obtained products were assessed for their nutritional value (energy value, protein, fats, dietary fibre,...
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Characterization of volatile compounds, structural, thermal and physico-mechanical properties of cross-linked polyethylene foams degraded thermo-mechanically at variable times
PublikacjaWaste cross-linked polyethylene foam (wXLPE) was thermo-mechanically degraded at variable time using internal batch mixer. The progress of wXLPE degradation has been investigated by using a simultaneous thermogravimetric/differential scanning calorimetry analyzer coupled with Fourier transform infrared spectroscopy, swelling measurements, tensile tests and scanning electron microscopy. Volatile organic compounds generated during...
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Non-regulated organic compounds (NROC's) in the Odra River water samples.
PublikacjaW ramach badań opisanych w pracy podjęto próbę identyfikacji lotnych i średniolotnych związków z grupy Non-Regulated Organic Compounds obecnych w próbkach wody rzecznej. Analizie poddano 25 próbek wód pobranych z rzeki Odry w październiku 2000, w trakcie VIII kampanii zorganizowanej w ramach International Odra Project (IOP). W badaniach wykorzystano technikę PT-TD-GC-MS.Komputerowa analiza widm masowych wykazała obecność wielu...
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Profile of phenolic compounds and antioxidant activity of organically and conventionally grown black-grain barley genotypes treated with biostimulant
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MICROPROPAGATION, ANTIOXIDANT ACTIVITY, TOTAL PHENOLICS AND FLAVONOIDS CONTENT OF GARDENIA JASMINOIDES ELLIS AS AFFECTED BY GROWTH REGULATORS
PublikacjaThis investigation has been carried out to study Micropropagation of Gardenia jasminoides Ellis shootlet,induction and growth of callus and enhancement of antioxidant, total phenolics and flavonoids content in shootlet andcalli. The results revealed that for shooting stage adding 2 or 3 mg/l BAP gave the highest shootlet number/explant. Butadding 3 mg/l 2iP produced the longest shootlet and leaves number. The...
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Monitoring and analytics of semivolatile organic compounds (SVOCs) in indoor air
PublikacjaThis paper reviews literature information on the behaviour of semivolatile organic compounds (SVOCs) in the indoor environment, as well as the most likely emission sources. The consecutive stages of analytical procedures used for monitoring SVOCs in indoor environments are described. The most common approaches used for collecting samples from the gas and particulate phases are mentioned. The paper discusses and compares various...
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Organic compounds in indoor environments
PublikacjaPraca jest przeglądem literaturowym dotyczącym obecności lotnych związków organicznych w powietrzu wewnętrznym. Zaprezentowano główne źródła zanieczyszczeń powietrza wewnętrznego, poruszono tematykę sumarycznej zawartości LZO oraz wpływu zanieczyszczeń powietrza atmosferycznego na jakość powietrza wewnętrznego.
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Inhibition of cancer antioxidant defense by natural compounds
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Ground Tire Rubber Modified by Elastomers via Low-Temperature Extrusion Process: Physico-Mechanical Properties and Volatile Organic Emission Assessment
PublikacjaIn this paper, low-temperature extrusion of ground tire rubber was performed as a proecological waste tires recycling method. During this process, ground tire rubber was modified with constant content of dicumyl peroxide and a variable amount of elastomer (in the range: 2.5–15 phr). During the studies, three types of elastomers were used: styrene-butadiene rubber, styreneethylene/butylene-styrene grafted with maleic anhydride and...
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Comparative evaluation of different methods for determining phytochemicals and antioxidant activity in products containing betalains - Verification of beetroot samples
PublikacjaThis study presents methods that can be used to assess the health quality of products containing betalains. The paper compares and verifies data on the phytochemical composition of three different pigmented beetroot cultivars using spectrophotometric, HPLC-DAD, HPTLC and LC-Q-Orbitrap-HRMS techniques. Additionally, we compared the total antioxidant activity in both the cell-free and cellular systems. Betalain contribution to antioxidant...
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The impact of cooking method on the phenolic composition, total antioxidant activity and starch digestibility of rice (Oryza sativa L.)
PublikacjaThis study investigated changes in the phenolic composition, total antioxidant activity (TAA) and starch digestibility in white and brown rice due to three different cooking procedures, and subsequent reheating of cooked rice after storage. Among the analyzed samples, brown rice showed the highest TAA and phenolic content (622.5 mg kg-1 DW). All cooking methods resulted in significant decrease of phenolic content and TAA of rice...
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The Application of Lamiaceae Lindl. Promotes Aroma Compounds Formation, Sensory Properties, and Antioxidant Activity of Oat and Buckwheat-Based Cookies
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Biodegradation of organic compounds by activated sludge
PublikacjaBadano biodegradalność pestycydów zawartych w ściekach z zakładów syntezy organicznej przez osad czynny z oczyszczalni komunalnej i przemysłowej. Zbadano również odporność mikroorganizmów osadu czynnego na syntetyczne związki organiczne zawarte w ściekach farmaceutycznych. W trakcie badań prowadzona była kontrola mikroskopowa osadu czynnego. Badania prowadzone były na modelu laboratoryjnym oczyszczalni ścieków. Największą odporność...
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Proton affinities of simple organic compounds
PublikacjaThe Restricted Hatree-Fock method with 6-311G** split-valence molecular orbitals basis sets has been applied to geometrical optimizations and calculations of total electronic, zero point vibrational energies and proton affinities at 298 K for small neutral and protonated alkanes, alcohols, acetic acid, methyl and ethyl acetate, acetone, and acetaldehyde. Calculated values of proton affinities are compared with experimental data.
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The effect of freeze-drying and storage on lysozyme activity, lactoferrin content, superoxide dismutase activity, total antioxidant capacity and fatty acid profile of freeze-dried human milk
PublikacjaPooled human milk samples were freeze-dried and stored for 6 weeks at a temperature of 5 C and 25 C. Freeze-drying decreased the water content of milk by 86.5%, and the obtained lyophilizate was readily soluble in water. The freeze-drying process did not affect superoxide dismutase (SOD) activity, fatty acid (FA) profile or lactoferrin (LF) content, but it decreased total antioxidant capacity (TAC) of human milk by 22.1% and induced...
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Deep eutectic solvents – based green absorbents for effective volatile organochlorine compounds removal from biogas
PublikacjaVolatile organochlorine compounds (VOXs) presented in biogas can cause many technological and environmental problems. During the combustion of biogas containing VOXs, the corrosion of installation, as well as the formation of toxic by-products (polyhalogenated dioxins and furans) and further emission to the atmosphere, may occur. Therefore, in this study, a new procedure based on physical absorption was developed. In order to meet...
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Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions
PublikacjaCavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and...
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Measurements of Activity Coefficients at Infinite Dilution for Organic Solutes in the Ionic Liquids N-Ethyl- and N-Octyl-N-methylmorpholinium Bis(trifluoromethanesulfonyl)imide. A Useful Tool for Solvent Selection
PublikacjaIn recent years, many papers describing ionic liquids (IL) as promising solvents in separation techniques have been published. The conscious choice of appropriate ionic liquid as absorption media in effective extraction of selected types of analytes requires deeper understanding of the analyte−IL interactions. Therefore, intensive research is conducted to determine the values of activity coefficient at infinite dilution, which...
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Volatile organohalogen compounds in human urine: the effect of environmental exposure
PublikacjaW pracy przedstawiono wyniki oznaczania lotnych związków chlorowcoorganicznych w próbkach moczu pochodzących m.in. od dawcow narazonych na kancerogeny w miejscu pracy i dawcow spozywajacych wode poddana procesowi uzdatniania przez chlorowanie. Do izolacji i wzbogacania analitów z moczu, posiadającego skomplikowaną matrycę, wykorzystano technikę analizy fazy nadpowierzchniowej nad cienką warstwą cieczy z samoczynną generacją ciekłego...
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Identification of volatile compounds based on the electrocatalytic gas sensor responses
PublikacjaMeasured response in case of electrocatalytic gas sensors is in form of a voltamperometric characteristic. Current-voltage (I-V) response shape depends on the gas type and its concentration. Such response contains significantly more information comparing with typical electrochemical sensors, but is quite difficult to analyze. When I-V curve contains current peaks, position of such peaks can be used...
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Identification of volatile compounds in raw spirits of different organoleptic quality
PublikacjaGłównym celem prezentowanych badań było określenie składu lotnej frakcji destylatów rolniczych, a następnie wyodrębnienie profili zapachowych destylatów rolniczych różniących się właściwościami sensorycznymi ocenionymi na podstawie klasycznej analizy sensorycznej. Profile zapachowe tworzono z wykorzystaniem kapilarnej chromatografii gazowej połączonej ze spektrometrią mas (GC-MS). Do ekstrakcji lotnych związków zastosowano technikę...
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Separation of volatile compounds from fermentation broth by membrane distillation
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Gentiana asclepiadea exerts antioxidant activity and enhances DNA repair of hydrogen peroxide- and silver nanoparticles-induced DNA damage
PublikacjaExposure to high levels of different environmental pollutants is known to be associated with induction of DNA damage in humans. Thus DNA repair is of great importance in preventing mutations and contributes crucially to the prevention of cancer. In our study we have focused on quantitative analysis of Gentiana asclepiadea aqueous or methanolic extracts obtained from flower and haulm, their antioxidant potency in ABTS post-column...
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Antioxidant Activities and Volatile Flavor Components of Selected Single-Origin and Blend Chocolates
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Persulfate activation by organic compounds: advancements and challenges
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Modeling hydrolysis of slowly biodegradable organic compounds in biological nutrient removal activated sludge systems
PublikacjaHydrolysis is an important process in biological wastewater treatment and is known to be the ratelimiting step in organic carbon removal from municipal or industrial wastewater. The influence of the readily biodegradable chemical oxygen demand fraction in biological wastewater treatment systems has been extensively investigated, but little is known about the effects of slowly biodegradable substrate (XS) on denitrification and...
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Activity of Polish unifloral honeys against pathogenic bacteria and its correlation with colour, phenolic content, antioxidant capacity and other parameters.
PublikacjaThe use of honey as an antimicrobial agent gains importance due to often ineffectiveness of conventional treatment. However, activity of honey depends mainly on its botanical and geographical origin. To date, antimicrobial potential of Polish honeys has not yet been entirely investigated. In this study, 37 unifloral samples of 14 honey types (including rare varieties) from Poland were analysed and compared with manuka honey. The...
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New matrix-free reference materials of volatile compounds - application of glass fibres as support materials for surface compounds
PublikacjaTechnika termicznego rozkładu związków powierzchniowych, znana od ponad dziesięciu lat, ulega ciągłym udoskonaleniom w celu otrzymywania coraz szerszej gamy wzorców analitycznych występujących na coraz niższych poziomach stężeń. Początkowo w roli nośnika stosowano żel krzemionkowy, który w trakcie dalszych faz rozwoju tej techniki zastąpiono kolejno szkłem porowatym, a następnie włóknem szklanym. W ostatnim czasie uproszczono układ...
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Analytical techniques for trace organic compounds-III: Mass spectrometry in trace organic analysis
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Effects of organic compounds on the macroalgae culture of Aegagropila linnaei
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Anticariogenic effects of extracts and fractions of Potentilla recta and their antioxidant activity
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The effect of chlorinated drinking water consumption on levels of volatile organohalogen compounds in urine.
PublikacjaW przedstawionej pracy podjęto próbę oznaczenia niezmienionych form lotnych rozpuszczalników chlorowcoorganicznych w próbkach materiału biologicznego jakim jest mocz dawców, używających w gospodarstwie domowym a także w pracy wody uzdatnianej między innymi w procesie chlorowania. Do wykonania oznaczeń zastosowano zmodyfikowaną technikę analizy fazy nadpowierzchniowej nad cienką warstwą cieczy z samoczynną generacją ciekłego sorbentu...
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Chemically modified glass fiber as a matrix-free reference material for volatile compounds
PublikacjaW pracy opisano sposób wytwarzania nowego typu bezmatrycowych materiałów odniesienia lotnych związków organicznych. Do otrzymywania lotnych analitów wykorzystano technikę termicznego rozkładu związków powierzchniowych. Jako nośnik zastosowano modyfikowane chemicznie włókna szklane. Związkiem oznaczanym był chlorek metylu.
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Edible Flowers Extracts as a Source of Bioactive Compounds with Antioxidant Properties—In Vitro Studies
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Phenolic Compounds and Antioxidant Properties of Fermented Beetroot Juices Enriched with Different Additives
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Investigation of stability of aqueous solutions containing trace amounts of volatile organic analytes
PublikacjaOznaczając lotne związki chlorowcoorganiczne w matrycy wodnej należy uwzględnić specyficzne właściwości, którymi charakteryzują się te związki, a mianowicie:- niska temperatura wrzenia; - wysoka prężność pary nad roztworem; - stosunkowo niska rozpuszczalność w wodzie.Właściwości te należy uwzględnić w trakcie przygotowania wodnych roztworów wzorcowych wykorzystywanych na etapie kalibracji i badań modelowych. Ze względu na istotność...
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Volatile organic compound separation from gas phase using ionic liquids
PublikacjaZanieczyszczenie powietrza lotnymi związkami organicznymi staje się światowym problemem ochrony środowiska w związku z ich toksycznymi właściwościami. W związku z tym poszukuje się nowych, efektywnych technologii oczyszczania strumieni gazowych. Powszechnie stosowaną metodą jest utlenianie termiczne. Wiąże się ono jednak z Wysokiem zużyciem energii i efektami ubocznymi w postaci emisji dwutlenku węgla i tlenków azotu. Alternatywą...
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Evaluation of polycaprolactone as a new sorbent coating for determination of polar organic compounds in water samples using membrane–SPME
PublikacjaCommercially available solid-phase microextraction fibers used for isolation of polar analytes are based on the adsorption phenomenon. In consequence, typical limitations bonded with analytes displacement and matrix effects are very frequent. In the present study, alternative solution is described. Polycaprolactone (PCL) was used for the first time as sorbent to isolate polar organic compounds from water samples using the membrane–solid-phase...