Contribution Of Different Components Research Articles

Irreversibility analysis of a separation system using sieve tray distillation column

An attempt has been made (1) to develop an expression for evaluating irreversibility due to vapour-liquid contact on trays, and (2) to assess the effects of the following parameters on the irreversibility of the total process: (1) relative contribution of different components to the total process irreversibility, i.e. the relative effects of the column trays, condenser, reboiler and associated fluid handling system, (2) variation in column configuration parameters like feed plate location and heat removal from the trays using circulation flux, (3) variation of the major design parameters of the sieve trays, i.e. hole diameter and weir height, and thereby evolve a strategy for performance optimization based on process irreversibility

Autonomic pathways in development of neural stimulation-induced gastric mucosal damage.

Gastric mucosal erosions can be induced by electrical stimulation of either vagus nerves (5 Hz, 5 V, 1 ms) or the paraventricular nucleus (PVN) of the hypothalamus (200 microA, 60 Hz, 100-microseconds pulse width). We have utilized various pharmacological and surgical interventions to determine the contributions of different components of the autonomic nervous system to the development of this neurally induced gastric damage in urethan-anesthetized Sprague-Dawley rats. In all experiments damage was assessed macroscopically and scored blindly on a 0 (normal) to 3 (severe) scale with samples sectioned for subsequent histological assessment of damage at the light microscopic level. Animals pretreated with either hexamethonium (30 mg/kg iv) or atropine (2 mg/kg iv) demonstrated reduced gastric damage scores after vagal stimulation compared with untreated control animals (P < 0.05). In contrast animals that underwent cervical cord transection exhibited gastric damage after both vagal and PVN stimulation that was not significantly different compared with animals with an intact cord undergoing similar stimulation (P > 0.05). Such cord transection itself did not cause any significant change to the gastric mucosa in the time period studied. These data emphasize the importance of the autonomic nervous system, in particular the parasympathetic component in the development of vagal stimulation-induced gastric damage. In addition, the present studies suggest that neither vagal nor PVN stimulation-induced gastric damage is dependent on neural projections to sympathetic preganglionic neurons of the intermediolateral cell column of the spinal cord.

Near Infrared Calibrations for Goat's Milk Components: Protein, Total Casein, αs-, β- and k-caseins, Fat and Lactose

A fast and inexpensive method to quantify the main constituents of goat's milk using near infrared (NIR) spectroscopy, is proposed. Since the efficiency of milk-to-cheese transformation depends on the total amount of casein, as well as on the relative proportions of the different types of caseins, it is desirable to quantify not only protein, fat and lactose, as is normally done routinely in the cheese industry and milk recording schemes, but also total casein, αs-, β- and k-caseins. Quantities of these main components have been measured in milk samples of three Spanish breeds of goats, using traditional chemical, electrophoretical and densitometric laboratory methods in order to produce NIR calibrations for total protein, total casein, casein fractions (αs-, β- and k-caseins), fat and lactose. Low standard errors and high coefficients of determinations have been obtained for the calibrations and validations. Goat's milk spectra are described, and the contribution of different components to the observed pattern is discussed. Due to the low cost, facility and rapidity of the analyses after the spectrophotometer has been calibrated for each milk component, the use of near infrared spectroscopy becomes a suitable tool to analyse large numbers of samples and, therefore, very suitable for dairy goat recording schemes.

Scattering From a Straight Thin Wire Resonator

ABSTRACT The scattering of a plane wave by a straight thin wire of finite length and finite conductivity is investigated. Current excited in such a wire was studied by the method of parabolic equations in [l]. In the present paper, this current is used to calculate a scattered field. Two approximate expressions are found for the scattered field. They have different analytic forms but lead to very close numerical results. One of them satisfies the reciprocity principle exactly and the other one satisfies this principle only approximately. The contribution of different components of a current to the scattered field is determined.

Calculation of deformation energies and conformations in lipid membranes containing gramicidin channels

In this paper we calculate surface conformation and deformation free energy associated with the incorporation of gramicidin channels into phospholipid bilayer membranes. Two types of membranes are considered. One is a relatively thin solvent-free membrane. The other is a thicker solvent-containing membrane. We follow the approach used for the thin membrane case by Huang (1986) in that we use smectic liquid crystal theory to evaluate the free energy associated with distorting the membrane to other than a flat configuration. Our approach is different from Huang, however, in two ways. One is that we include a term for surface tension, which Huang did not. The second is that one of our four boundary conditions for solving the fourth-order differential equation describing the free energy of the surface is different from Huang's. The details of the difference are described in the text. Our results confirm that for thin membranes Huang's neglect of surface tension is appropriate. However, the precise geometrical form that we calculate for the surface of the thin membrane in the region of the gramicidin channel is somewhat different from his. For thicker membranes that have to deform to a greater extent to accommodate the channel, we find that the contribution of surface tension to the total energy in the deformed surface is significant. Computed results for the shape of the deformed surface, the total energy in the deformed surface, and the contributions of different components to the total energy, are presented for the two types of membranes considered. These results may be significant for understanding the mechanisms of dimer formation and breakup, and the access resistance for ions entering gramicidin channels.

Infrared Emission at High Galactic Latitude

Results obtained with the Infrared Astronomy Satellite (IRAS) on the IR emission at high galactic latitude are reviewed. We present evidence for the detection of galactic emission at 12, 25, 60, and 100 μm. We describe the morphology of this emission and summarize work on the correlation of IR cirrus with H I, CO, and optical emission. We discuss the contribution of the neutral atomic, ionized, and molecular gas to the total IR emission and the contribution of different components of interstellar dust to the emission seen at different wavelengths.

The vertical attenuation of light in Charlotte Harbor, a shallow, subtropical estuary, south-western Florida

The relative contribution of different components to the attenuation of photosynthetically active radiation was determined in the Charlotte Harbor estuarine system based on laboratory and in situ measurements. Agreement between laboratory and in situ measurements of the attenuation coefficient ( k t ) was good ( r 2 = 0·92). For all in situ measurements ( n = 100), suspended, non-chlorophyll matter accounted for an average of 72% of k t , dissolved matter accounted for 21%, suspended chlorophyll for 4%, and water for the remaining 3%. For individual determinations, suspended non-chlorophyll matter, dissolved matter, suspended chlorophyll, and water, each accounted for as much as 99%, 79%, 21%, and 18% of k t . Attenuation by suspended matter was greatest near the mouth of the northern tidal rivers and was variable over the rest of the estuarine system. Attenuation by dissolved matter was greatest in the brackish tidal rivers and decreased with increasing salinity. Attenuation due to dissolved matter was positively correlated with water color. The source of the color was basin runoff. Wavelength transmittance changed along the salinity gradient. Maximum transmittance shifted from 500 to 600 nm in gulf waters to 650 to 700 nm in colored, brackish waters. Dissolved matter was primarily responsible for the large attenuation at short wavelengths (400–500 nm).

Mercury Pollution in the Surface Environment of a Volcanic Area

Abstract The mercury content has been determined in samples of fumarolic gases, phreatic waters, soil and vegetation collected at Vulcano, Aeolian Islands, Italy. Volcanic activity is demonstrated as a source of natural mercury pollution whose extent has been evaluated here by studying the contribution of different components of the surface environment. The possible influences for living organisms are examined.

Inclusion of structural forces in the theory of stability of colloids and films

On the basis of an analysis of the experimental and theoretical data, the parameters of an exponential isotherm of the structural component of disjoining pressure for liquid interlayers and films are found. Inclusion of the isotherm of structural forces, II s( h), in the DLVO theory and the heterocoagulation theory permitted to explain the phenomena of stability and the reversible coagulation of the hydrophilic sols of silica, as well as to plot the isotherm of disjoining pressure of the wetting aqueous films on the quartz surface, II( h). Using Frumkin-Derjaguin's equation and theoretical isotherms, II( h), as the basis, the values of contact angles are calculated. The methods for controlling the wetting, which is due to a change in the contribution of different components of long-range surface forces to the II( h) isotherm of wetting films, are considered.

Changes in the ability of malonyl-CoA to inhibit carnitine palmitoyltransferase I activity and to bind to rat liver mitochondria during incubation in vitro. Differences in binding at 0 degree C and 37 degrees C with a fixed concentration of malonyl-CoA.

Time courses for inhibition of carnitine palmitoyltransferase (CPT) I activity in, and [14C]malonyl-CoA binding to, liver mitochondria from fed or 48 h-starved rats were obtained at 37 degrees C by using identical incubation conditions and a fixed concentration of malonyl-CoA (3.5 microM), which represents the middle of the physiological range observed previously [Zammit (1981) Biochem. J. 198, 75-83] Incubation of mitochondria in the absence of malonyl-CoA resulted in a time-dependent decrease in the ability of the metabolite instantaneously to inhibit CPT I and to bind to the mitochondria. Both degree of inhibition and binding were restored in parallel over a period of 6-8 min on subsequent addition of malonyl-CoA to the incubation medium. However, the increased inhibition of CPT I activity on addition of mitochondria directly to malonyl-CoA-containing medium was not accompanied by an increase in the amount of [14C]malonyl-CoA bound to mitochondria at 37 degrees C. Time courses for binding of [14C]malonyl-CoA performed at 0 degree C were different from those obtained at 37 degrees C. There was little loss of ability of [14C]malonyl-CoA to bind to mitochondria on incubation in the absence of the metabolite, but there was a time-dependent increase in binding on addition of mitochondria to malonyl-CoA-containing medium. It is suggested that these temperature-dependent differences between the time courses obtained may be due to the occurrence of different changes at 37 degrees C and at 0 degree C in the relative contributions of different components (with different affinities) to the binding observed at 3.5 microM-malonyl-CoA. Evidence for multi-component binding was obtained in the form of strongly curvilinear Scatchard plots for instantaneous (5s) binding of malonyl-CoA to mitochondria. Such multi-component binding would be expected from previous results on the different affinities of CPT I for malonyl-CoA with respect to inhibition [Zammit (1984) Biochem. J. 218, 379-386]. Mitochondria obtained from starved rats showed qualitatively the same time courses as those described above, with notable quantitative differences with respect both to the absolute extents of CPT I inhibition and [14C]malonyl-CoA binding achieved as well as to the time taken to attain them.

Differential modulation by muscimol of [3H] flunitrazepam binding to benzodiazepine binding site subtypes

The effects of the GABA agonist, muscimol on [(3)H]flunitrazepam binding were examined in cerebellum and hippocampus regions proposed to contain different populations of benzodiazepine binding site subtypes. Quantitative analysis was made of the contribution of different components of [(3)H]flunitrazepam binding by utilising the selective affinities of propyl ?-carboline-3-carboxylate for these sites. The influence of muscimol on each of these components was determined and the results provide clear evidence that GABA receptors interact with only some subtypes of benzodiazepine binding sites; for example, whilst the cerebellar site and the low affinity hippocampal site are influenced, the high affinity site in hippocampus appears to be quite unaffected.