Search results for " concentration"
showing 10 items of 1684 documents
Use of a three-factor interpretive optimisation strategy in the development of an isocratic chromatographic procedure for the screening of diuretics …
2000
Screening of diuretics in urine is feasible through direct injection of the samples into the chromatographic system and isocratic reversed-phase liquid chromatography (RPLC) with micellar-organic mobile phases of sodium dodecyl sulfate (SDS) and 1-propanol. The surfactant coverage of the chromatographic column makes the addition of organic competing amines less necessary than in conventional aqueous-organic RPLC to achieve well-shaped peaks. Also, the range of elution strengths of micellar mobile phases required to elute mixtures of hydrophobic and hydrophilic diuretics is smaller. This allows the isocratic separation of the diuretics within adequate analysis times. An interpretive methodol…
A hyaluronic acid/cyclodextrin based injectable hydrogel for local doxorubicin delivery to solid tumors
2020
Localized delivery of anticancer drugs is often the most useful therapeutic approach for the treatment of solid tumors. The use of injectable polymeric systems that maximize drug concentration in the proximal area of the tumor represents an extremely advantageous therapeutic strategy. Here, the development of an injectable in situ forming hydrogel was accomplished by exploiting the azo-type Michael reaction between an amine derivative of hyaluronic and vinylsulfone functionalized -cyclodextrins complexing doxorubicin. This injectable system can be easily prepared and administered with timelines compatible with normal operating room procedures, as demonstrated by rheological tests. In vitro…
Durability of a 3D woven composite assisted by finite element multi-scale modelling
2012
International audience; The textile composite studied is a 3D woven composite. A unit cell is defined by using microscopic examinations of the microstructure. A multiscale approach assisted by the finite element method is performed in order to estimate the effective properties of the composite and then to access to local stress field. This approach allows the determination of the kind of load to which warp yarns are subjected. Moreover, detailed analysis of damaged model using different configurations of broken yarns are treated. The evolution of the stress concentration coefficient highlight the load transfers due to consecutive yarn breaks.
A genomic reappraisal of symbiotic function in the aphid/Buchnera symbiosis: reduced transporter sets and variable membrane organisations.
2011
International audience; Buchnera aphidicola is an obligate symbiotic bacterium that sustains the physiology of aphids by complementing their exclusive phloem sap diet. In this study, we reappraised the transport function of different Buchnera strains, from the aphids Acyrthosiphon pisum, Schizaphis graminum, Baizongia pistaciae and Cinara cedri, using the re-annotation of their transmembrane proteins coupled with an exploration of their metabolic networks. Although metabolic analyses revealed high interdependencies between the host and the bacteria, we demonstrate here that transport in Buchnera is assured by low transporter diversity, when compared to free-living bacteria, being mostly bas…
Interaction of allopurinol with phenprocoumon in man.
1977
Conditions in two patients on long-term phenprocoumon (Marcumar®) treatment are reported who had signs of phenprocoumon overdosage when given simultaneously allopurinol. The determination of phenprocoumon plasma concentrations in one patient showed that phenprocoumon accumulates for several weeks during treatment with allopurinol. Signs of phenprocoumon overdosage thus can appear long time after starting allopurinol treatment.
Adsorption of methotrexate and calcium leucovorin onto cholestyramine in vitro.
2003
Abstract Methotrexate (MTX), an antimetabolite of folic acid, is a drug widely used in the treatment of different types of cancer. When high doses are administered, it is necessary to interrupt its action by administering calcium leucovorin (CaL). The main pathway of MTX and CaL elimination in humans occurs through the kidney, but about 10% is excreted in the faeces via the bile. Drugs, foods and sorbents in intestinal lumen modify MTX and CaL reabsorption. Individual and simultaneous studies on the adsorption of MTX and CaL from aqueous phosphate buffer by cholestyramine were carried out in order to calculate the adsorption process of MTX and CaL to cholestyramine, and to characterize the …
Residual Stress Effects on Fatigue Crack Growth in Ti-6Al-4V Friction Stir Welds
2008
Recent studies have illustrated a predominant role of the residual stress on the fatigue crack growth in friction stir welded joints. In this study, the role of the residual stress on the propagation of fatigue cracks orthogonal to the weld direction in a friction stir welded Ti-6Al-4V joint was investigated. A numerical prediction of the fatigue crack growth rate in the presence of the residual stresses was carried out using AFGROW software; reasonable correspondence between the predictions and the experimental results were observed when the effects of residual stress were included in the simulation.
Numerical experimental analysis of hybrid double lap aluminum-CFRP joints
2015
Abstract Due to their reliability and ease of assembly, both the adhesively bonded and the mechanical joints are commonly used in different fields of modern industrial design and manufacturing, to joint composite materials or composites with metals. As it is well known, adhesively bonded joints are characterized by high stiffness and good fatigue life, although delamination phenomena localized near the free edges may limit their use, especially for applications where corrosive environments and/or moisture can lead to premature failure of the bonding. In these cases, a possible alternative is given by the well-known mechanical joints. On the contrary, these last joints (bolted, riveted) requ…
UV filters: From sunscreens to human body and the environment
2007
Recognition of the harmful effects of ultraviolet (UV) radiation on the skin has triggered development of organic chemicals (commonly referred as UV filters) that can absorb UV radiation and attenuate the negative effects of sunlight exposure. Depending on the properties and the intended degree of protection, a wide array of combinations is being marketed as delivering protection against most kinds of UV-induced skin damage. However, some UV filters have dermatological implications, so maximum applicable concentrations have been established. To monitor to what extent commercial products comply with the mandatory limits, several analytical methods have been used for their determination in co…
Genomic evolution of bacterial populations under co-selection by antibiotics and phage
2017
Bacteria live in dynamic systems where selection pressures can alter rapidly, forcing adaptation to the prevailing conditions. In particular, bacteriophages and antibiotics of anthropogenic origin are major bacterial stressors in many environments. We previously observed that populations of the bacterium Pseudomonas fluorescens SBW25 exposed to the lytic bacteriophage SBW25Φ2 and a noninhibitive concentration of the antibiotic streptomycin (coselection) achieved higher levels of phage resistance compared to populations exposed to the phage alone. In addition, the phage became extinct under coselection while remaining present in the phage alone environment. Further, phenotypic tests indicate…