Search results for "Electric conductivity"

Monitoring pH and ORP in a SHARON reactor

2011

This paper analyses the valuable information provided by the on-line measurements of pH and oxidation reduction potential (ORP) in a continuous single high ammonia removal over nitrite (SHARON) reactor. A laboratory-scale SHARON reactor equipped with pH, ORP, electric conductivity and dissolved oxygen (DO) probes has been operated for more than one year. Nitrogen removal over nitrite has been achieved by adding methanol at the beginning of anoxic stages. Time evolution of pH and ORP along each cycle allows identifying the decrease in nitritation rate when ammonia is consumed during the aerobic phase and the end of the denitrification process during the anoxic phase. Therefore, monitoring pH…

Elaboration of ammonia gas sensors based on electrodeposited polypyrrole - cobalt phthalocyanine hybrid films

2013

The electrochemical incorporation of a sulfonated cobalt phthalocyanine (sCoPc) in conducting polypyrrole (PPy) was done, in the presence or absence of LiClO4, in order to use the resulting hybrid material for the sensing of ammonia. After electrochemical deposition, the morphological features and structural properties of polypyrrole/phthalocyanine hybrid films were investigated and compared to those of polypyrrole films. A gas sensor consisting in platinum microelectrodes arrays was fabricated using silicon microtechnologies, and the polypyrrole and polypyrrole/phthalocyanine films were electrochemically deposited on the platinum microelectrodes arrays of this gas sensor. When exposed to a…

Inactivation and tachyphylaxis of heat-evoked inward currents in nociceptive primary sensory neurones of rats.

2000

In contrast to other sensory modalities, pain does not decrease when a noxious stimulus is applied at constant intensity (Greene & Hardy, 1962). From this lack of adaptation on the perceptive level it has traditionally been implied that primary nociceptive afferents also do not adapt upon constant stimulation. This is in contrast to the results of recordings from these afferents, which exhibit pronounced adaptation for physical as well as chemical stimuli (Meyer et al. 1994). Peripheral adaptation of nociceptive nerve endings is compensated by central summation (Mendell & Wall, 1965; Price et al. 1977); this slow summation process of small fibre input to the dorsal horn of the spinal cord i…

Sorption of copper(II) ions in the biomass of alga Spirogyra sp.

2012

Abstract Sorption of copper ions by the alga Spirogyra sp. was investigated to determine the influence of experimental conditions and the methods of sample preparation on the process. The experiments were carried out both under the static and the dynamic conditions. Kinetics and equilibrium parameters of the sorption were evaluated. In addition, the influence was studied of the algae preparation methods on the conductivity of demineralized water in which the algae samples were immersed. The static experiments showed that the sorption of Cu2+ ions reached equilibrium in about 30 min, with approximately 90% of the ions adsorbed in the initial 15 min. The sorption capacity determined from the …

Glucagon-like peptide-1 modulates neurally evoked mucosal chloride secretion in guinea pig small intestine in vitro

2011

Glucagon-like peptide-1 (GLP-1) acts at the G protein-coupled receptor, GLP-1R, to stimulate secretion of insulin and to inhibit secretion of glucagon and gastric acid. Involvement in mucosal secretory physiology has received negligible attention. We aimed to study involvement of GLP-1 in mucosal chloride secretion in the small intestine. Ussing chamber methods, in concert with transmural electrical field stimulation (EFS), were used to study actions on neurogenic chloride secretion. ELISA was used to study GLP-1R effects on neural release of acetylcholine (ACh). Intramural localization of GLP-1R was assessed with immunohistochemistry. Application of GLP-1 to serosal or mucosal sides of fla…

Effects of chemical and surgical ganglionectomy on electrical activity of the pineal gland of male rats.

1986

In order to elucidate further the role of sympathetic innervation for pineal function, the influence of sympathectomy on the spontaneous electrical activity of single cells in the pineal gland of adult male rats was investigated. Extracellular single-unit recordings were made during nighttime in the pineal gland of urethane-anesthetized, blinded adult male rats that had been treated neonatally with 6-hydroxydopamine, or that were ganglionectomized either during, or 12-16 h or 36-40 h, prior to the recording experiment. These experiments revealed that the excitatory influence of the sympathetic system on pineal nocturnal electrical activity can be abolished by either chemical sympathectomy o…

Effects of Substantia Nigra Stimulation on Electrical and Mechanical Activities of the Duodeno-Jejunal Loop, in the Cat

1985

The effect of substantia nigra stimulation on duodeno-jejunal intraluminal pressure and electrical activity was analysed in the cat. An inhibitory influence was noted to occur on both the intestinal pressure and the electrical response activity (ERA): the effect seemed to be in correlation with the stimulus parameters employed. After bilateral vagotomy, the inhibition remained substantially unchanged. The possibility of the existence of a sympathetic pathway mediating the effect is emphasized.

Nitrate, sulphate and chloride contents in public drinking water supplies in Sicily, Italy.

2012

Water samples collected from public drinking water supplies in Sicily were analysed for electric conductivity and for their chloride, sulphate and nitrate contents. The samples were collected as uniformly as possible from throughout the Sicilian territory, with an average sampling density of about one sample for every 7,600 inhabitants. Chloride contents that ranged from 5.53 to 1,302 mg/l were correlated strongly with electric conductivity, a parameter used as a proxy for water salinity. The highest values are attributable to seawater contamination along the coasts of the island. High chloride and sulphate values attributable to evaporitic rock dissolution were found in the central part of…

Room-temperature electrical addressing of a bistable spin-crossover molecular system.

2011

Synthetic nanopores with fixed charges: An electrodiffusion model for ionic transport

2003

Synthetic nanopores with fixed charges exhibit ionic equilibrium and transport properties that resemble those displayed by biological ion channels. We present an electrodiffusion model based on the Nernst-Planck flux equations, which allows for a qualitative description of the steady state ionic transport through a nanopore when the membrane fixed charges and all mobile carriers (including the water ions) are properly taken into account. In particular, we study the current-voltage curve, the electrical conductance, the reversal potential (a measure of the nanopore ionic selectivity), as well as the flux inhibition by protons and divalent cations in the nanopore. The model clearly shows how …