Search results for "Concentration."
showing 10 items of 1849 documents
Orientation of charged clay nanotubes in evaporating droplet meniscus.
2015
© 2014 Elsevier Inc. During drying, an aqueous suspension of strongly charged halloysite clay nanotubes concentrates at the edge of the droplet ("coffee-ring" effect) which provides alignment of the tubes along the liquid-substrate contact line. First, the surface charge of the nanotubes was enhanced by polyanion adsorption inside of the lumen to compensate for the internal positive charges. This increased the magnitude of the ξ-potential of the tubes from -36 to -81mV and stabilized the colloids. Then, colloidal halloysite was dropped onto the substrate, dried at 65°C and after a concentration of ~0.05mgmL-1 was reached, the alignment of nanotubes occurred starting from the droplet edges. …
Synthesis of fluorinated oxadiazoles with gelation and oxygen storage ability
2012
A new family of fluorinated low molecular weight (LMW) gelators has been synthesized through SNAr substitution of 5-polyfluoroaryl-3-perfluoroheptyl-1,2,4-oxadiazoles with glycine ester. The obtained compounds give thermal and pH-sensitive hydrogels or thermo-reversible organogels in DMSO. Oxygen solubility studies showed the ability to maintain high oxygen levels in solution and in gel blend with plate counter agar (PCA).
Dried-Fruit Storage: An Analysis of Package Headspace Atmosphere Changes
2019
The quality of packaged dried foods depends on storage conditions and is determined largely by the initial gas composition inside and the transference through the container. The aim of this work was to analyze the O2 and CO2 concentrations within the internal atmosphere of the packaging. In this study, dried apricots and raisins were packaged in glass jars and polypropylene trays thermosealed with different polymers, and stored at 5, 15, 25, and 35 °
Phytochemical Profile and Antioxidant, Antiproliferative, and Antimicrobial Properties of Rubus idaeus Seed Powder
2022
In the context of the contemporary research on sustainable development and circular economy, the quest for effective strategies aimed at revaluation of waste and by-products generated in industrial and agricultural production becomes important. In this work, an ethanolic extract from red raspberry (Rubus idaeus) seed waste (WRSP) was evaluated for its phytochemical composition and functional properties in term of antioxidative, antiproliferative, and antimicrobial activities. Chemical composition of the extract was determined by both HPLC-ESI-MS/MS and spectrophotometric methods. Phytochemical analysis revealed that flavan-3-ols and flavonols were the major phenolic compounds contained in W…
The role of freshwater copepods in the environmental risk assessment of caffeine and propranolol mixtures in the surface water bodies of Spain
2019
In this study we aimed at assessing: (i) the environmental risk posed by mixtures of caffeine and propranolol to the freshwater ecosystems of Spain; (ii) the sensitivity of freshwater copepod species to the two compounds; (iii) if the toxicity of caffeine and propranolol to freshwater copepods contributes to the environmental risk posed by the two compounds in the freshwater bodies of Spain. The environmental risk was computed as the ratio of MECs (i.e. the measured environmental concentrations) to PNECs (i.e. the respective predicted no-effect concentrations). The effects of caffeine and propranolol on the freshwater cyclopoid Diacyclops crassicaudis crassicaudis were tested both individua…
Mathematical modeling of oral absorption and bioavailability of a fluoroquinolone after its precipitation in the gastrointestinal tract
2013
The objective was to characterize the in vivo absorption and bioavailability (BA) of a low solubility, high permeability fluoroquinolone (CNV97101) that precipitates in the gastrointestinal (GI) tract by mathematical modeling approach. In situ rat intestinal perfusion studies were performed to characterize the absorption mechanism. The oral fraction absorbed in vivo was lower than the predicted based on the in situ intestinal permeability. Two additional routes of administration, intraduodenal (ID) and intraperitoneal (IP) were investigated to explore if precipitation in stomach and subsequent partial re-dissolution were the causes of the lower in vivo BA. Ex vivo precipitation studies with…
Effects of Dissolved Organic Material on Binding and Toxicokinetics of Pyrene in the Waterflea Daphnia magna
2001
The binding and bioavailability of pyrene was studied in the laboratory in two humic fresh waters and in a reference water without dissolved organic material (DOM), measured as dissolved organic carbon (DOC). The uptake of pyrene by Daphnia magna in short-term (24 h) accumulation experiments was fitted to a first-order rate-kinetic equation to calculate simultaneous uptake and elimination rates. The partition coefficients of pyrene to DOC (KDOC) were 37.1 x 103 in Pielisjoki River (9.4 mg DOC L(-1)), and 34.9 x 103 in Lake Kontiolampi (17.4 mg DOC L(-1)) waters, indicating similar binding affinities of pyrene for both humic waters. The uptake clearance of pyrene (ku) in the DOC-rich Lake Ko…
The effects of woodchip- and straw-derived biochars on the persistence of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in soils
2014
Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. This study assessed the influence of two biochars, made from woodchips and straw at a pyrolysis temperature of 725°C and applied to a loamy sand and a sandy soil in the concentration of 5.3 g 100 g(-1) sandy soil and 4.1 g 100 g(-1) loamy sand soil, or 53 t ha(-1) for both soil types, on degradation of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Soils were spiked with 50 mg MCPA kg(-1) soil. In the sandy soil, significantly more MCPA remained after 100 days if amended with straw-derived biochar in comparison to wood-derived biochar. Both biochars types si…
Potential use of grapevine cv Askari for heavy metal phytoremediation purposes at greenhouse scale
2020
Grapevine varieties possess desirable characteristics for phytoremediation purposes. We investigated the potential of grapevine cv Askari in phytoremediation of heavy metal (HM) pollutions. In total 80 grapevine seedlings were exposed to four levels of HM stress (mild, low, moderate, and severe) in greenhouse condition during two growing years (2018 and 2019). The HM concentrations (Zn, Cu, Cd, Cr, and Pb) were subsequently determined in the soils, roots, and grapevine aboveground parts (AGPs), and then phytoextraction and phytostabilization potential assessment indices, i.e., biological absorption coefficient (BAC), bioconcentration factor (BCF), and translocation factor (TF), were calcula…
Effects of Terbuthylazine on Soil Fauna and Decomposition Processes
1996
Abstract Acute lethal and sublethal effects of terbuthylazine and the commercial herbicide preparation Gardoprim [terbuthylazine is the active ingredient (a.i.)] on soil organisms (microbes, oppioid mites, two gamasid mite species, enchytraeids, and nematodes) were studied. In the humus soil terbuthylazine had no toxic effects on soil animals tested. However, the herbicide preparation had acute toxic effects on enchytraeids [no-observed-effect level (NOEL) 1.0 g a.i./m 2 ] and both gamasid mites (NOEL 2.4 and 5.0 g a.i./m 2 ). According to filter paper test, the LC 50 value for oppioid mites was 14.5 g a.i./m 2 . In the humus soil the commercial preparation caused no dose-related mortality …