Search results for "otas"

Organelle pH studies using targeted avidin and fluorescein–biotin

2000

Abstract Background: Mammalian organelles of the secretory pathway are of differing pH. The pH values form a decreasing gradient: the endoplasmic reticulum (ER) is nearly neutral, the Golgi is mildly acidic and the secretory granules are more acidic still (∼pH 5). The mechanisms that regulate pH in these organelles are still unknown. Results: Using a novel method, we tested whether differences in H + ‘leak' and/or counterion conductances contributed to the pH difference between two secretory pathway organelles. A pH-sensitive, membrane-permeable fluorescein–biotin was targeted to endoplasmic-reticulum- and Golgi-localized avidin-chimera proteins in HeLa cells. In live, intact cells, ER pH (…

Thermodynamic characterisation of novel solutions for closed-loop reverse electrodialysis

2018

Closed-loop reverse electrodialysis is a novel technology to convert low-grade heat directly into electricity. It consists of a reverse electrodialysis unit coupled with a regeneration unit in which the waste-heat is used to restore the initial conditions of the two solutions. One of the most impor- tant advantages of closed-loop system is the possibility to select an ad-hoc salt solution to obtain high efficiency. In this regard, it is important to assess how the salt solution properties affect the performance of the energy generation and solution regeneration processes. The aim of this study is to analyse the effect of thermodynamic properties of non-conventional salt solutions within a R…

The short-circuited everted sac of rat colon mucosa.

1981

A short-circuited preparation of everted rat colon sacs is described. The serosal current electrode is a AgAgCl wire. A cylindrical agar bridge or AgAgCl electrode may be employed on the mucosal side. Effects of Ag+ ions liberated from the electrodes on ion transport could not be demonstrated. Fluid and sodium are absorbed and bicarbonate secreted. Potassium and chloride movements are not significantly different from zero. The preparation remains stable for at least 2 h. Sodium absorption is diminished by 50% and bicarbonate secretion abolished in the absence of glucose. In principle, similar ion transport properties were found as in Ussing-chamber preparations. The advantage of the everted…

Domain-Enhanced Interlayer Coupling in Ferroelectric/Paraelectric Superlattices

2004

We investigate the ferroelectric phase transition and domain formation in a periodic superlattice consisting of alternate ferroelectric (FE) and paraelectric (PE) layers of nanometric thickness. We find that the polarization domains formed in the different FE layers can interact with each other via the PE layers. By coupling the electrostatic equations with those obtained by minimizing the Ginzburg-Landau functional we calculate the critical temperature of transition Tc as a function of the FE/PE superlattice wavelength and quantitatively explain the recent experimental observation of a thickness dependence of the ferroelectric transition temperature in KTaO3/KNbO3 strained-layer superlatti…

Design of a compact diode laser system for dual-species atom interferometry with rubidium and potassium in space

2017

We report on a micro-integrated high power diode laser based system for the MAIUS II/III missions. The laser system features fiber coupled and frequency stabilized external cavity diode lasers (ECDL) for laser cooling, Bose-Einstein condensate (BEC) generation and dual species atom interferometry with rubidium and potassium on board a sounding rocket.

All-Solid-State Ag+-ISE Based on [2.2.2]p,p,p-Cyclophane

2001

All-solid-state ion-selective electrodes (ISEs) based on two ionophores with similar structure, i.e., [2.2.2] p,p,p-cyclophane and [2.2.2]m,p,p-cyclophane, were prepared and investigated. The ion-selective membranes were composed of the corresponding ionophore (1 %), potassium tetrakis(4-chlorophenyl)borate (0.5 %), 2-nitrophenyl octyl ether (65–66 %), and PVC (33 %). The ion-selective membrane was placed on top of a layer of the conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), working as ion-to-electron transducer. The resulting all-solid-state ISEs were conditioned in 0.01 M AgNO3 and investigated as Ag+-ISEs. The results show that [2.2.2] p,p,p-cyclophane is much more select…

Nota sobre La Presidencia Española del Consejo Europeo

1989

The diagnosis and management of gastric cancer: Expert discussion and recommendations from the 12th ESMO/World Congress on Gastrointestinal Cancer, B…

2011

Well-recognized experts in the field of gastric cancer discussed during the 12th European Society Medical Oncology (ESMO)/World Congress Gastrointestinal Cancer (WCGIC) in Barcelona many important and controversial topics on the diagnosis and management of patients with gastric cancer. This article summarizes the recommendations and expert opinion on gastric cancer. It discusses and reflects on the regional differences in the incidence and care of gastric cancer, the definition of gastro-esophageal junction and its implication for treatment strategies and presents the latest recommendations in the staging and treatment of primary and metastatic gastric cancer. Recognition is given to the ne…

Wechselwirkungen zwischen Na+-, Ca2+- und K+-Einflüssen auf Dynamik und Kontraktilität des Myokards

1969

The relaxant effects of cromakalim (BRL 34915) on human isolated airway smooth muscle

1992

Cromakalim (BRL 34915) is a potassium channel opener with therapeutic potential as a bronchodilator in asthma. Cromakalim (0.1–30 μmol/l) inhibited the spontaneous tone of human isolated bronchi n a concentration-related manner being nearly as effective as isoprenaline or theophylline. The order of relaxant potencies (expressed as -log10 IC50 mol/l; mean ±SEM) was isoprenaline (7.29 ± 0.27; n = 8) > cromakalim (5.89 ± 0.12; n = 7) > theophylline (4.07 ±0.13; n = 10). In human bronchi where tone had been raised by addition of histamine (0.1 mmol/l), acetylcholine (0.1 mmol/l) or leukotriene D4 (LTD4, 0.1 μmol/l), the relaxant effect of cromakalim was substantially reduced. Cromakalim suppres…