Search results for "Pressure"

Single hollow fiber SLM extraction of polyamines followed by tosyl chloride derivatization and HPLC determination

2007

Determination of polyamines in biological fluids possesses medical diagnostic relevance. Despite the vast panel of analytical methods developed for polyamines they are not applied in routine clinical usage, mainly due to the time and labor consuming sample preparation step and complicated derivatization procedures. Thus, new simpler methods are needed. This paper describes a single hollow fiber SLM extraction method of polyamines followed by simple pre-column derivatization with tosyl chloride and HPLC-UV analysis. The influence of different parameters such as the extraction time, organic phase composition, acceptor pH, donor pH, acceptor volume, donor volume and stirring speed on the trans…

Short-term effects of potassium fertilization on the hydraulic conductance of Laurus nobilis L.

2011

This study reports experimental evidence on the effect of short term potassium fertilization on potassium uptake, tissue concentration and hydraulic conductance of pot-grown laurel plants. Potassium uptake and loading into the xylem of laurel seedlings increased within 24 h from fertilization. Potassium was not accumulated in roots and leaves, but the [K+] of xylem sap was 80% higher in fertilized plants (+K) than in potassium starved plants (-K), likely as a result of recirculation between xylem and phloem. This increase in xylem sap [K+] resulted in a 45% increase in transpiration rate, a 30% increase in plant hydraulic conductance (Kplant) and a 120% increase in leaf specific conductivit…

The Global Blood Pressure Screening Campaign of the International Society of Hypertension

2020

Elevated blood pressure remains the single biggest risk factor contributing to the global burden of disease and mortality. May Measurement Month is an annual global screening campaign aiming to improve awareness of blood pressure at the individual and population level. Adults (≥18 years) recruited through opportunistic sampling were screened at sites in 92 countries during May 2019. Ideally, 3 blood pressure readings were measured for each participant, and data on lifestyle factors and comorbidities were collected. Hypertension was defined as a systolic blood pressure ≥140 mm Hg, or a diastolic blood pressure ≥90 mm Hg (mean of the second and third readings) or taking antihypertensive medic…

Systemic vascular resistance predicts the development of hypertension : the cardiovascular risk in young Finns study

2020

To study whether systemic hemodynamics, especially systemic vascular resistance, predicts the development of hypertension and improves the risk prediction of incident hypertension beyond common risk factors in the risk models in young adults. Typical risk factors for hypertension in the risk prediction models (systolic and diastolic blood pressure, parental history of hypertension, age, sex, body-mass index, smoking), laboratory values (high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, glucose, insulin, C-reactive protein), heart rate (HR), stroke index (SI), and systemic vascular resistance index (SVRI) calculated by whole-body impedance cardiography…

Letter to the Editor. Idiopathic normal pressure hydrocephalus: is 1-year follow-up enough?

2022

Evolution of intermolecular contacts with temperature and pressure in bromoethane and iodo­ethane – a comparative study

2022

At ambient conditions two liquids, bromo­ethane, C2H5Br (MBE, m.p. 154.6 K) and iodo­ethane, C2H5I (MIE, m.p. 162.1 K), have been crystallized under both isobaric and isochoric conditions using in situ low-temperature and high-pressure techniques. The single-crystal X-ray diffraction studies, supported by the isothermal compressibility and isobaric differential scanning calorimetry measurements, allowed the monitoring and analysis at low temperature and high pressure of the effects of externally induced changes in MBE and MIE. The monoclinic MBE and MIE crystals are found to be isostructural. They are stable, in the investigated regimes, i.e. down to 100 K/0.1 MPa and up to ∼295 K/3.7 GPa, …

Characterization of gas flow through low-permeability claystone: laboratory experiments and two-phase flow analyses

2014

For the characterization of gas migration through a low-permeability clay host rock for deep underground repositories, a comprehensive understanding of the relevant phenomena of gas and fluid flow through low-permeability clay is required. The National Cooperative for the Disposal of Radioactive Waste (Nagra) in Switzerland has developed a comprehensive programme to characterize gas flow in low-permeability Opalinus Clay through laboratory tests and detailed numerical analyses for developing appropriate constitutive models. Laboratory tests were performed on cores by two different laboratories, the Laboratory for Soil Mechanics at EPFL and the Department of Geotechnical Engineering and Geos…

Tumour oxygenation during fractionated radiotherapy--comparison with size-matched controls.

1999

The effect of fractionated irradiation on the oxygenation status of experimental tumours was investigated using polarographic assessment of the pO2 distribution. Since an improvement in tumour oxygenation could simply be the result of tumour shrinkage, a comparison of pO2 readings of untreated size-matched control tumours was performed. Irradiation was carried out using 6 fractions of 6 Gy applied within 11 days. A comparison of polarographic pO2 data with size-matched untreated tumours revealed a significant improvement in oxygenation after the irradiation. The median pO2 was 0.9+/-0.1 mm Hg for unirradiated tumours at a volume of 180 mm3, while the corresponding data for irradiated tumour…

Capsaicin desensitization in vivo is inhibited by ruthenium red.

1990

The effect of systemic administration of Ruthenium Red on the excitatory and desensitizing effect of capsaicin was investigated in rats. Ruthenium Red was injected s.c. 30 min before capsaicin was administered. The excitatory effect of capsaicin on corneal, perivascular and visceral afferents was not influenced by treatment with Ruthenium Red. However, determination of the neuropeptide content and evoked neuropeptide release in peripheral organs and dorsal spinal cord 48 h after treatment showed that Ruthenium Red attenuated the 'desensitizing' effect of capsaicin at peripheral, but not at central, endings of primary afferents. On the other hand, a capsaicin-elicited autonomic reflex mediat…

Trace Analysis of Plutonium and Technetium by Resonance Ionization Mass Spectrometry Using an Atomic Beam and a Laser Ion Source

1990

A method for low level detection of plutonium and technetium is described with a detection limit of less than 107 atoms. Plutonium is a very toxic element due to its radioactive decay as well as its chemical behaviour. It was released to the environment in large amounts during the fifties and sixties of his century, principally by nuclear-weapon tests and some accidents. As a result about 0.4 − 4 mBq per gram 239Pu(T1/2 = 24390 y), corresponding to 4 × 108 − 4 × 109 atoms, can be found in the Northern Hemisphere in soil samples.