Search results for "Branes"
showing 10 items of 525 documents
The Diapause Lipidomes of Three Closely Related Beetle Species Reveal Mechanisms for Tolerating Energetic and Cold Stress in High-Latitude Seasonal E…
2020
During winter insects face energetic stress driven by lack of food, and thermal stress due to sub-optimal and even lethal temperatures. To survive, most insects living in seasonal environments such as high latitudes, enter diapause, a deep resting stage characterized by a cessation of development, metabolic suppression and increased stress tolerance. The current study explores physiological adaptations related to diapause in three beetle species at high latitudes in Europe. From an ecological perspective, the comparison is interesting since one species (Leptinotarsa decemlineata) is an invasive pest that has recently expanded its range into northern Europe, where a retardation in range expa…
Dynamic changes in the subcellular distribution of the tobacco ROS-producing enzyme RBOHD in response to the oomycete elicitor cryptogein.
2014
Highlight text The oomycete elicitor cryptogein triggers the relocation of RBOHD from intracellular compartments to the plasma membrane in tobacco cells. This suggests that intracellular trafficking is a potential determinant of RBOHD activity.
Supported liquid membrane extraction with single hollow fiber for the analysis of fluoroquinolones from environmental surface water samples
2010
Abstract In this work, the simple analytical method for the determination of four fluoroquinolone antibiotics: ciprofloxacin, enrofloxacin, norfloxacin and danofloxacin, in environmental surface water samples is described. Sample pretreatment step was performed by the application of a technique based on supported liquid membrane extraction with the configuration of single hollow fiber (HF-SLM). The HPLC system with diode array detection was used for final analysis of studied analytes. Various parameters affecting the extraction efficiency during HF-SLM enrichment, such as type of membrane diluent, pH of donor (sample) and acceptor phases, as well as an enrichment time and salt content of sa…
Cytotoxic Activity of Organotin(IV) Derivatives with Triazolopyrimidine Containing Exocyclic Oxygen Atoms
2020
In this study cytotoxicity of organotin(IV) compounds with 1,2,4-triazolo[1,5-a]pyrimidines, Me3Sn(5tpO) (1), n-Bu3Sn(5tpO) (2), Me3Sn(mtpO) (3), n-Bu3Sn(mtpO) (4), n-Bu3Sn(HtpO2) (5), Ph3Sn(HtpO2) (6) where 5HtpO = 4,5-dihydro-5-oxo-[1,2,4]triazolo-[1,5-a]pyrimidine, HmtpO = 4,7-dihydro-5-methyl-7-oxo-[1,2,4]triazolo-[1,5-a]pyrimidine, and H2tpO2 = 4,5,6,7-tetrahydro-5,7- dioxo-[1,2,4]triazolo-[1,5-a]-pyrimidine, was assessed on three different human tumor cell lines: HCT-116 (colorectal carcinoma), HepG2 (hepatocarcinoma) and MCF-7 (breast cancer). While 1 and 3 were inactive, compounds 2, 4, 5 and 6 inhibited the growth of the three tumor cell lines with IC50 values in the submicromolar …
A simple novel configuration for in-vial microporous membrane liquid–liquid extraction
2009
Abstract A novel arrangement for microporous membrane liquid–liquid extraction from the aqueous donor phase to the organic acceptor phase within a micro-vial, which is compatible with the chromatograph autosampler is presented. The device consisted of a stoppered glass micro-vial containing the organic solvent where the septum of the screw stopper was replaced by a sized piece of membrane which is hermetically assembled to the volumetric flask containing the aqueous donor solution. The placement of the membrane in alternative contact with the solutions was achieved by orbital agitation. As a preliminary study, 2-ethylhexyl 4-(dimethylamino)benzoate has been determined (limit of quantificati…
Determination of volatile organic compounds in contaminated air using semipermeable membrane devices
2009
Abstract Semipermeable membrane devices (SPMDs) were evaluated as passive samplers for the determination of 26 volatile organic compounds (VOCs) in contaminated air of occupational environments. A direct methodology based on the use of head-space-gas chromatography–mass spectrometry (HS-GC–MS) was developed for VOCs determinations in SPMDs, without any sample pre-treatment and avoiding the use of solvents. A desorption temperature of 150 °C for 10 min was sufficient for a sensitive VOCs determination providing limits of detection in the range of 15 ng SPMD−1 for 21 of 26 studied compounds. Linear and equilibrium uptake models were established for each VOC from compound isotherms. Highly vol…
Halloysite nanotubes for efficient loading, stabilization and controlled release of insulin
2018
Hypothesis: Oral insulin administration is not actually effective due to insulin rapid degradation, inactivation and digestion by proteolytic enzymes which results in low bioavailability. Moreover insulin is poorly permeable and lack of lipophilicity. These limits can be overcome by the loading of protein in some nanostructured carrier such as halloysite nanotubes (HNTs). Experiments: Herein we propose an easy strategy to obtain HNT hybrid materials for the delivery of insulin. We report a detailed description on the thermal behavior and stability of insulin loaded and released from the HNTs hybrid by the combination of several techniques. Findings: Release experiments of insulin from the H…
Transport of dipeptides and phosphono dipeptides through an immobilized liquid membrane. Stereoselectivity of the process
1993
Abstract Dipeptide and phosphono dipeptide hydrochlorides permeated well through a 1-decanol membrane supported in a porous polyethylene hollow fiber matrix. This transfer is easily accomplished either by passive or by carrier-facilitated (with Kryptofixes 222 or 5 present in the membrane phase) transport. The transport is stereoselective with l-l dipeptides being transported faster than their l-d isomers.
Time-resolved fluorescence and fourier transform infrared spectroscopic investigations of lateral packing defects and superlattice domains in composi…
2003
Time-resolved fluorescence and Fourier transform infrared spectroscopies were used to investigate the lateral organization of lipids in compositionally uniform and fully equilibrated 1-palmitoyl-2-oleoyl-phosphatidylcholine/cholesterol (POPC/CHOL) liposomes prepared by a recently devised low-temperature trapping method. Independent fluorescence decay lifetime and rotational dynamics parameters of diphenylhexatriene (DPH) chain-labeled phosphatidylcholine (DPH-PC) in these liposomes were recovered from the time-resolved fluorescence measurements as a function of cholesterol molar fraction (X(CHOL)) at 23 degrees C. The results indicate significantly greater lifetime heterogeneity, shorter av…
Widening the applicability of AnMBR for urban wastewater treatment through PDMS membranes for dissolved methane capture: Effect of temperature and hy…
2021
[EN] AnMBR technology is a promising alternative to achieve future energy-efficiency and environmental-friendly urban wastewater (UWW) treatment. However, the large amount of dissolved methane lost in the effluent represents a potential high environmental impact that hinder the feasibility of this technology for full-scale applications. The use of degassing membranes (DM) to capture the dissolved methane from AnMBR effluents can be considered as an interesting alternative to solve this problem although further research is required to assess the suitability of this emerging technology. The aim of this study was to assess the effect of operating temperature and hydrodynamics on the capture of…