Search results for " press"

Determination of bupivacaine in human plasma by high-performance liquid chromatography.

1984

Comparison of the performance of butanol and pentanol as modifiers in the micellar chromatographic determination of some phenethylamines

2000

Abstract A procedure was developed for the determination of several phenethylamines (amphetamine, arterenol, ephedrine, phenylephrine, phenylpropanolamine, mephentermine, methoxyphenamine, pseudoephedrine and tyramine), using micellar mobile phases of sodium dodecyl sulfate (SDS), a C18 column and UV detection. The drugs were eluted at short retention times with conventional acetonitrile–water or methanol–water mobile phases. In contrast, in the micellar system, they were strongly retained due to association with the surfactant adsorbed on the stationary phase, and needed the addition of butanol or pentanol to be eluted from the column. These modifiers allowed a simple way of controlling th…

Experimental „Luxury Perfusion” in the Cerebral Cortex of the Cat

1968

Publisher Summary Preliminary studies have been performed, on the changes of cortical rCBF (Krypton- 85 Beta clearance technique) in response to a localized pressure applied to the cerebral cortex (suprasylvian gyrus) of 8 cats under Nembutal anesthesia (30 to 40 mg/kg bodyweight). No change in rCBF is found at regions as distant as the contralateral hemisphere. The increase of rCBF at the compressed site, during the compression, seems to be more marked in animals with higher blood (i.e. perfusion) pressure, and may be absent in cats with blood pressure of about 80 mm Hg. The augmentation of rCBF around the compressed area during the compression is always very marked, and after some time fl…

Carbonyl reductase 1 is a predominant doxorubicin reductase in the human liver.

2008

A first step in the enzymatic disposition of the antineoplastic drug doxorubicin (DOX) is the reduction to doxorubicinol (DOX-OL). Because DOX-OL is less antineoplastic but more cardiotoxic than the parent compound, the individual rate of this reaction may affect the antitumor effect and the risk of DOX-induced heart failure. Using purified enzymes and human tissues we determined enzymes generating DOX-OL and interindividual differences in their activities. Human tissues express at least two DOX-reducing enzymes. High-clearance organs (kidney, liver, and the gastrointestinal tract) express an enzyme with an apparent Km of approximately 140 microM. Of six enzymes found to reduce DOX, Km valu…

CARS spectroscopy of CH4 for implication of temperature measurements in supercritical LOX/CH4 combustion

2007

International audience; Experimental and theoretical investigations of coherent anti-Stokes Raman spectroscopy of CH4 have been carried out. Experimental spectra were measured in a heated high-pressure test cell and compared with numerical simulations. Good agreement was obtained for the temperature and the pressure dependence of CARS spectra in the ranges 300-1100 K and 0.1-5.0 MPa. The observed dependencies provide useful guidance for CARS thermometry, allowing quantitative measurements of temperature in high-pressure combustors. Application of multiplex CH4 CARS thermometry for single-shot measurements in a LOX/CH4 combustion at high pressure was demonstrated at supercritical conditions …

How far are we from the valorization of waste-CO2 to formic acid via electrochemical routes for the applicative scale?

To date, the decarbonization of the world economy and storage and production of energy from alternative C-based sources is considered a relevant topic. The electrochemical conversion of CO2 has been widely investigated since the 1870s as a promising strategy to convert waste-CO2 into value-added chemicals [1,2]. Recently, it was highlighted that, among the several emerging technologies for CO2 conversion to value-added products on an applicative scale, electrochemical technologies are the closest to commercialization due to the numerous start-ups and established companies being invested in this area (e.g., Opus-12, Dioxide Material, and Carbon Recycling International) [3]. These technologie…

Effect of Pressure on the Electrochemical Conversion of CO2 to CO

2017

To minimize the negative effect of carbon dioxide as a greenhouse gas and introduce renewable energy in the chemical and energy chain, an interesting approach is the Carbon Capture and Conversion. In this context, one of more appealing conversion strategies is the el Ectrochemical reduction of CO2, which could combines the utilization of excess electric energy from intermittent renewable sources with CO2 (1). Furthermore, CO2 can be selectively converted into various useful chemicals by changing the operating conditions of electrolysis. In particular, an increasing attention has been devoted to the electrochemical conversion of carbon dioxide to carbon monoxide (2,3). The main obstacle of t…

Effect of tiotropium/olodaterol combination therapy on long-term heart rate and blood pressure in COPD patients

2018

Introduction: Cardiovascular (CV) comorbidities are common in COPD, and associated with poor prognosis. LABAs and LAMAs are established COPD treatments whose pharmacology would suggest the potential to increase heart rate (HR) and impact blood pressure (BP). However, previous studies indicate that HR and BP are not negatively influenced by tiotropium (Tio) or olodaterol (Olo) monotherapy. Aims: To determine the effect of dual bronchodilation with Tio/Olo (T/O) on HR and BP. Methods: The 52-week, Phase III TONADO® studies (NCT01431274/NCT01431287) evaluated T/O 5/5 µg, Tio 5 µg or Olo 5 µg, via the Respimat® inhaler, in GOLD 2–4 COPD patients. In this post hoc analysis, long-term changes fro…

Measurement of brain tissue pressure in cold induced cerebral oedema.

1973

Experiments were performed in order to evaluate the concept that brain oedema is associated with an increase in local interstitial fluid pressure. Assuming that the pressure measured by the cotton wick technique represents the hydrostatic interstitial fluid pressure, the tissue pressure was recorded with pressure transducers in the white matter adjacent and remote to a local cold injury, in the opposite hemisphere, and in the cisterna magna. In 9 cats during steady-state conditions mean tissue pressures between 1.20±0.30 mm Hg and 2.33±0.80 mm Hg were found, as compared to a mean CSF pressure of 5.17±0.82 mm Hg. The tissue pressure was found to increase significantly adjacent to the lesion …

Simultaneous determination of eight underivatised biogenic amines in fish by solid phase extraction and liquid chromatography-tandem mass spectrometr…

2010

Biogenic amines on fish tissue are formed as a result of bacterial contamination and spoilage during storage. A new method based on liquid chromatography (LC) and tandem mass spectrometry (MS/MS) using a triple quadrupole (QqQ) analyser was developed for the analysis of eight biogenic amines (cadaverine, histamine, phenylethylamine, putrescine, spermine, spermidine, tyramine and tryptamine) in fish tissues. Sample preparation was performed by extraction with trichloroacetic acid 5% and solid phase extraction clean up with STRATA X cartridge. The MS/MS method was validated and compared with a method based on the analysis of dansyl derivatives by LC and fluorescence detector (FD). MS/MS achie…