Percentage Of Depletion Research Articles

Glutamate transport alteration triggers differentiation-state selective oxidative death of cultured astrocytes: a mechanism different from excitotoxicity depending on intracellular GSH contents.

Recent evidence has been provided for astrocyte degeneration in experimental models of neurodegenerative insults associated with glutamate transport alteration. To determine whether astrocyte death can directly result from altered glutamate transport, we here investigated the effects of L-trans-pyrrolidine-2,4-dicarboxylate (PDC) on undifferentiated or differentiated cultured rat striatal astrocytes. PDC induced death of differentiated astrocytes without affecting undifferentiated astrocyte viability. Death of differentiated astrocytes was also triggered by another substrate inhibitor but not by blockers of glutamate transporters. The PDC-induced death was delayed and apoptotic, and death rate was dose and treatment duration-dependent. Although preceded by extracellular glutamate increase, this death was not mediated through glutamate receptor stimulation, as antagonists did not provide protection. It involves oxidative stress, as a decrease in glutathione contents and a dramatic raise in reactive oxygen species preceded cell loss, and as protection was provided by antioxidants. PDC induced a similar percentage of GSH depletion in the undifferentiated astrocytes, but only a slight increase in reactive oxygen species. Interestingly, undifferentiated astrocytes exhibited twofold higher basal GSH content compared with the differentiated ones, and depleting their GSH content was found to render them susceptible to PDC. Altogether, these data demonstrate that basal GSH content is a critical factor of astrocyte vulnerability to glutamate transport alteration with possible insights onto concurrent death of astrocytes and gliosis in neurodegenerative insults.

The size dependence of chloride depletion in fine and coarse sea-salt particles

The size dependence of the percentage of chloride depletion (%Cl dep) in sea-salt aerosols was investigated using 16 sets of 48–96 h size distribution measurements of atmospheric aerosols, collected from June 2000 to May 2001 in Hong Kong. Chloride and sodium in HK are predominantly from sea-salt aerosols because the prevailing wind is from the sea. In the particles larger than 1.8 μm (coarse particles), the %Cl dep generally decreased with increasing particle size, consistent with the literature. In the particles smaller than 1.8 μm (fine particles), the mode diameter of %Cl dep was associated with the mode diameter of sulfate in the droplet mode. When the sulfate peak appeared at 0.32–0.54 μm, the %Cl dep peaked at 0.54–1.0 μm. Heterogeneous reactions between sea-salt particles and acidic gases are the major routes of the sulfate formation and chloride depletion, leading to a decrease in the %Cl dep with increasing particle size. When the sulfate peak appeared at 0.54–1.0 μm, the maximum %Cl dep appeared at 1.0–1.8 μm and the %Cl dep increased with increasing particle size in the fine mode. Both heterogeneous reactions and in-cloud processes occurred to form sulfate and to deplete chloride. However, heterogeneous reactions, sampling artifacts, and anthropogenic emissions of chloride cannot explain this observed size dependence. Cloud processing including the activation of sea-salt particles with subsequent SO 4 2− formation, the neutralization by NH 3 and the evaporation of HCl in conjunction with NH 3 during water evaporation from cloud droplets can cause chloride depletion in the droplet mode. The smaller amount of evaporation of NH 3 and HCl from cloud droplets in forming the 0.54–1.0 μm particles than the 1.0–1.8 μm particles can account for the observed size dependence of %Cl dep although direct evidence based on cloud measurements is not available.

Isolation of a fungus from denitrifying activated sludge that degrades highly chlorinated dioxins

This article reports the potential of denitrifying activated sludge to degrade highly chlorinated dioxins, especially from a (landfill) leacheate treatment plant in Japan, and the isolation from this denitrifying activated sludge of a microorganism able to degrade highly chlorinated dioxins. Using a 700-ml bioreactor, denitrifying activated sludge was cultivated under denitrifying conditions by adding 2.0 ng of a mixture of 4- to 8-chlorinated dioxins from fly ash. The dioxin contents of the sample, effluent, and medium before and after cultivation were measured by gas chromatography–mass spectrometry (GC–MS). After 7 days cultivation, about 90% of added dioxins were lost (average percentage of isomer depletion). A dioxin-degrading microorganism was isolated from the activated sludge. Lignin was added to the medium as a color indicator of aromatic compound degradation, and the lignin-decolorizing microorganisms in the denitrifying activated sludge were screened. Some strains were isolated, and one major isolated fungus, strain 622, decolorized lignin effectively. Strain 622 was identified as an Acremonium sp. from its morphological characteristics. It could decolorize lignin by 24% under paraffin-sealed anaerobic conditions. After the cultivation of strain 622 with a 2 ng/ml mixture of 4- to 8-chlorinated dioxins for 1 day, 82% (average for individual isomers) of the added 4- to 8-chlorinated dioxins had been degraded. Added octachlorodibenzo-p-dioxin (OCDD, 100 ng) was degraded under aerobic conditions after 8 h of incubation. During this process, heptachlorodibenzo-p-dioxin was produced and appeared to be a degradation product of OCDD. 1- or 2-hydroxydibenzo-p-dioxin from OCDD was also identified as the degradation product by GC–MS. These results indicated that OCDD was degraded to the nonchlorinated dibenzo-p-dioxins through dechlorination by Acremonium sp. strain 622.

Synthese et caractérisation de catalyseurs a base de cuivre: application a la réaction d'oxydation du phénol

Abstract Synthesis and characterization of copper catalysts: application to the oxidation of phenol. The catalytic oxidatin of organic pollution has already been treated several publications reporting the use of ozone, air or hydrogen peroxide as oxidants. These systems require very severe conditions of temperature and pressure. It was thus useful to develop active, stable and inexpensive oxidizing systems. For this purpose we prepared catalysts by impregnation of copper on a natural clay; these catalysts were characterized, then used in the reaction of oxidation of phenol in the presence of hydrogen peroxide, at atmospheric temperature and pressure. The results showed a very significant activation of hydrogen peroxide by the catalyst, the phenol depletion percentage reaching 65 % after 4 h, and very significant stability of the catalyst.

Experimental study of the sampling artifact of chloride depletion from collected sea salt aerosols.

Sampling artifact of chloride depletion from collected sea salt particles was studied, based on simultaneous measurements of size distribution measurements by a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) and of PM2.5 measurements by a Compact Porous Metal Denuder Sampler (PMDS) at a coastal site in Hong Kong on May 7, 8, 9, 11, and 29, 1998. The ambient concentrations of SO2, HNO3, HNO2, and NH3 were also measured by the PMDS. PM2.5 measurements by the PMDS, which is equipped with denuders and nylon back filters, are compared with the PM1.8 and PM3.1 measurements by the MOUDI. The percentages of chloride depletion from sea salt aerosols in PM1.8 and PM3.1 were 4-45% higher than that in PM2.5. This suggests that chloride evaporation in PM1.8 and PM3.1 collected on Teflon filters of the MOUDI during sampling was present. From the sum of the contributions of particles on the Teflon and nylon filters of the PMDS, nitrate formation almost completely accounts for chloride depletion in PM2.5 prior to collection since the equivalent ratio of [Na+] to ([NO3-] + [Cl-]) is close to the seawater ratio of 0.85. However, it was found that 22-74% of nitrate and 45-86% of chloride in the collected particles on the Teflon filter of the PMDS evaporated during sampling. Excess chloride depletion unexplained by NO3- and nss-SO4(2-) was found in the collected particles on the Teflon filter of the PMDS. Similarly, an amount of 3.7-27.2 nequiv m-3 of excess depleted chloride (equivalent to 8-55% of total chloride depletion) was found in supermicron particles collected by the MOUDI. In the 1.8-3.1 microns particles, the excess depleted chloride is positively correlated to the chloride evaporated from the deposited particles. Particle--particle interactions are proposed to explain the evaporation of nitrates and chlorides in the PMDS and MOUDI measurements. The observed chloride depletion from seasalt aerosols was partially attributed to sampling artifact due to particle--particle interactions.

Birdsfoot Trefoil Seed Production: III. Seed Shatter and Optimal Harvest Time

Seed shattering is a major problem in birdsfoot trefoil (Lotus corniculatus L.) seed production and limited information is available describing the effects of agronomic practices on shatter losses. The objectives of this research were to: (i) quantify the effects of soil‐water availability on seed shatter and (ii) determine optimal harvest time on the basis of a heat unit method to minimize birdsfoot trefoil seed losses under western Oregon climatic conditions. Six treatments varying in water depletion percentage and replenishment amount were applied in 1994 and 1995 and two treatments in 1996 on a Woodburn silt loam soil (fine‐silty, mixed, mesic Aquultic Argixeroll) near Corvallis, OR. The total amount of shattered seeds was correlated with total harvested seed yield (r = 0.93). Crop water stress index (CWSI) was inversely related to the percentage of seeds shattered (r = −0.76). Increasing amounts of applied water increased the potential of seed yield shattered (r = 0.65). Seed shatter losses fluctuated during the late‐reproductive period, but were not influenced by irrigation or fluctuating climatic conditions. A total of 109 heat units (approximately 11 d), which were determined on the basis of a 10°C base temperature, were accumulated from the time of initial pod dehiscence until rapid seed shattering. The average seed yield losses due to shattering was 3 to 5.3 kg ha− d−1 The non‐irrigated control treatment generally produced more seeds than irrigated treatments. It is, thus, best not to irrigate birdsfoot trefoil grown for seed in western Oregon because increasing amounts of irrigation water increased seed shattering.

Birdsfoot Trefoil Seed Production: II. Plant‐Water Status on Reproductive Development and Seed Yield

Forage legume seed crop responses to water stress differ for each species, so a single optimal water management strategy is not applicable. The objectives of this study were to determine the effects of irrigation timing and replenishment amount on birdsfoot trefoil (Lotus corniculatus L.) reproduction and seed yield in the Willamette Valley of western Oregon, USA. Six treatments varying in water depletion percentage and replenishment amount were applied in 1994 and 1995 on a Woodburn silt loam soil (fine‐silty, mixed, mesic Aquultic Argixeroll) near Corvallis. In 1996, only a low stress (LS) that met the weekly crop evapotranspirative demand and a non‐irrigated control (C) treatment were investigated. In the first year of production, maintaining plants under low‐stress conditions sustained flowering longer than with limited or no irrigation. Flowering was not affected by irrigation in the subsequent two production years. Total above‐ground phytomass was correlated with the amount of irrigation water (r = 0.92). The C and all single application treatments had greater seed yields (SY) than the LS treatment in 1994. In 1995, all single application treatments had greater SY than the LS treatment. There was no difference between LS and C in 1995 and 1996. Umbel density and the number of seeds per pod were the primary determinants of total seed yield (r = 0.77 and 0.92, respectively). Optimal total seed production was achieved without supplemental irrigation under the humid temperate marine climatic conditions found in western Oregon.

Birdsfoot Trefoil Seed Production: I. Crop‐Water Requirements and Response to Irrigation

Forage legume seed crop reproduction can be modified by regulating soil-water availability. However, responses to water stress differ for each spedes, so a single optimal water management strategy is not available for all crops. The objectives of this research were to determine the crop-water requirements and the optimal water management conditions for birdsfoot trefoil (Lotus corniculatus L.) when grown for seed production under humid temperate marine climatic conditions of western Oregon, USA. The experiment was conducted on a Woodburn silt loam soil (fine-silty, mixed, mesic Aquultic Argixeroll) near Corvallis. Four single-application treatments varying in water depletion percentage (30 and 60% of field capacity) and replenishment amount (50 and 100% of amount depleted) were applied in 1994 and 1995. A low-stress treatment (LS) that received two to three applications per week of the amount depleted since the last application and a non-irrigated control were also investigated in 1994, 1995, and 1996. Increasing amounts of applied water resulted in increased seasonal crop evapotranspiration (ET C ) with plants grown under low-stress having the greatest ET C and non-irrigated control plants the least (r = 0.91). The fraction of available soil water used by non-irrigated plants was greatest and the LS treatment the least of all treatments. For non-irrigated conditions, the crop-water requirement ranged from 240 to 255 mm. Soil-water conditions favorable for high vegetative development were opposite of the conditions for optimal seed yield water-use efficiency, Unlike other forage legume seed crops, birdsfoot trefoil grown under these conditions required minimal or no supplemental irrigation to achieve maximal seed yield.

Heavy Metal-Induced Changes in the Glutathione Levels and Glutathione Reductase/Glutathione S-Transferase Activities in the Liver of Male Mice

Glutathione S-transferases catalyze the metabolism of reactive substances of exogenous or endogenous origin and are involved in inactivation processes of xenobiotics and their metabolites. The present study aims at investigating the influence of heavy metals on the hepatic level of reduced glutathione (GSH), glutathione S-transferase, and glutathione reductase activities in the liver of male mice after single-dose (1 and 24 h) and repeated-dose treatments (three consecutive days). The hepatic level of GSH was depleted after single-dose treatments with cadmium chloride, mercuric chloride, cobalt chloride, cesium chloride, lead acetate, and silver nitrate, and percentage of GSH depletion was greater still after the repeated-dose treatments. Nickel chloride, on the other hand, did not cause any change in the level of GS H after any period of treatment. Glutathione reductase activity was increased 24 hours after treatment with cadmium chloride, mercuric chloride, lead acetate, and silver nitrate, whereas cobalt chloride decreased such activity after repeated doses. With the exception of cadmium chloride, glutathione S-transferase activity was significantly decreased 24 hours after a single-dose treatment with all of the tested heavy metals. Such alterations in the activities of phase II drug-metabolizing enzymes as a result of heavy metal treatment may change the hepatic capacity for the detoxification of many toxic compounds from endogenous or exogenous sources.

Early, postnatal experience alters hypothalamic corticotropin-releasing factor (CRF) mRNA, median eminence CRF content and stress-induced release in adult rats

Rat pups 2–14 days of age were exposed daily to handling (15 min of separation from mother and home cage), maternal separation (MS; 180 min of comparable separation), or were left entirely undisturbed (non-handled; NH). As adults, MS rats showed increased hypothalamic corticotropin-releasing factor (CRF) mRNA levels compared with NH rats, while CRF mRNA levels in H rats were significantly lower than either MS or NH animals. Hypothalamic CRF content under basal conditions followed exactly the same pattern. A 20-min period of restraint stress produced significant CRF depletion in all groups, although the percentage of depletion was significantly lower in H animals compared with either MS or NH animals. Restraint stress produced significantly higher increases in plasma corticosterone in MS and NH animals than in H animals. These data reflect the importance of early environmental factors in regulating the development of the hypothalamic CRF system and the responsiveness of the hypothalamic-pituitary-adrenal axis to stress.

Leukocyte depletion filters: A comparison of efficiency

Four commercially available leukocyte depletion filters were evaluated using a flow cytometric technique to determine the efficiency of each type of filter. The Sepacell R-500A and the PALL RC50 were the most efficient in leukocyte depletion having a mean depletion percentage of 99.3% and 99.5%, respectively. The PALL RC100 which is used for two units also had a 99.3% depletion with the first unit but with the second unit the depletion dropped to 94.2%. The imugard IG-500 had a 97.3% depletion. Red cell recovery ranged from 87.4% for the PALL RC50 to 92.2% for the Sepacell R-500A.

Disposition of phencyclidine after intramuscular administration.

The disposition of radioactive phencyclidine (PCP) in various rat tissues, after single or repeated intramuscular injections for 23 days, have been investigated. Peak levels of radioactivity appeared 45-90 min after a single administration. The pancreas, salivary glands and mesenteric fat contained 4 to 6-fold higher radioactivity than brain, muscles, tendons, and bones. After repeated 3H-PCP injections, radioactivity levels showed a similar pattern as to that of the peak levels after a single administration, but at notably higher values. On the other hand, the percentage of depletion, within 48 h after the final injection, was the highest in the pancreas, salivary glands and mesenteric fat. It is possible that despite the low retention capacity of PCP radioactivity per unit weight of muscle, tendon and bone, they may be considered important reservoirs for either PCP, or its metabolites or both because of their large relative mass in the body.

Tele-methylhistamine as an index of the activity of central histaminergic neurons

The activity of histaminergic neurons was examined in various brain regions. Histamine (HA) and tele-methylhistamine (t-MH) were simultaneously assayed using HPLC with fluorescence detector. The HA content was high in the hypothalamus and thalamus and low in the cerebellum and pons-medulla oblongata in the rat, mouse and guinea-pig. The t-MH content was high in the hypothalamus and amygdala in all these species, and was exceptionally high in guinea-pig hippocampus. Pargyline hydrochloride (80 mg/kg, i.p.) increased the t-MH content of the rat brain linearly up to 4 hr after injection. The increments of t-MH (Δt-MH) were large in the hypothalamus, striatum and thalamus (108.7, 80.2 and 62.1 ng/g/hr, respectively), but very slight in the cerebellum (2.9 ng/g/hr). Although relatively high HA levels were observed in the spinal cord, no increase in t-MH was detected after pargyline treatment. There was a significant correlation between At-MH and steady-state t-MH levels in different brain regions (r = 0.82, p < 0.01). The treatment with α-fluoromethylhistidine (50 mg/kg, i.p.) produced 15-60 % depletion of HA 4 hr later in various rat brain regions except for the spinal cord. The percentage of depletion was regarded as that of neuronal HA to the total HA. The half-life of neuronal HA estimated from the methyl-ation rate by a one compartment open model was in a range of 7.7-56.6 min in the following rank order: striatum < hippocampus < midbrain < amygdala < cerebral cortex < pons-medulla oblongata < thalamus < hypothalamus. These results indicate that the t-MH levels and the increments after pargyline treatment are useful as indices of the brain histaminergic function.

A 31P-NMR study of the effects of reflow on the ischaemic rat heart

(1) The recovery of perfused rat hearts experiencing various lengths of total global ischaemia was studied using 31P-NMR. Mechanical function was monitored by measuring left ventricular pressure. (2) Hearts exposed to a maximum of 14 min total global ischaemia regained stable contractile function on reperfusion. The concentration of phosphocreatine in these hearts rapidly exceeded its pre-ischaemic value while that of ATP rose very slowly. P i fell on reflow to approximately its original level. These observations are interpreted as being the result of a rapid turnover of ATP stimulating phosphocreatine production by the mitochondrial isozyme of creatine kinase (ATP: creatine N-phosphotransferase, EC 2.7.3.2). (3) The recovery of intracellular pH on reperfusion does not depend upon the duration of ischaemia, nor on the pH or the percentage of ATP depletion at the end of the ischaemic period. This indicates that pH recovery is a flow-dependent phenomenon. (4) In non-recovering hearts, multiple P i resonances are observed which arise from areas of differing myocardial pH. Phosphocreatine levels did not rise above 50% of their pre-ischaemic values. ATP levels remained depressed. This suggests that localized tissue necrosis only characterizes the failing situation.

Lipid mobilization and food intake in experimentally obese mice bearing transplanted tumors.

SummaryA transplanted stomach tumor (CBA 2663) caused a striking decrease in total body lipid content and suppression of food intake while growing in GTG-obese and genetically “yellow obese” mice. Nonobese mice bearing the same tumor showed a comparable percentage of lipid depletion, but food intake decreased only as the host became moribund. The rate of lipid depletion was greater in the GTG-obese compared to nonobese hosts on a per gram tumor weight basis. Lipid depletion proceeded at a faster rate in GTG-obese (CBA × C57Bl)F1 hybrids bearing the CBA tumor compared to a sarcoma (C57B114) both having the same growth rate. Food intake was also rapidly depressed in the F1 hybrids bearing the CBA tumor, but not in those with the C57Bl sarcoma. It is suggested that the CBA tumor has some unique biological characteristics, which facilitates mobilization of body lipid stores which in turn influences food intake.

The Effects of the 1969 Tax Reform Act on Petroleum Property Values

The 1969 Tax "Reform" Act has seriously crippled the capability of the U.S. oil industry to meet the challenge of providing the tremendous energy needs of the 70's. If this challenge is not met, it will have been caused in great part by those in the Federal government, Congress, and the news media who have so successfully maligned the U. S. petroleum industry. Introduction The 27 1/2 percent depletion rate had been in effect 44 years before its reduction to 22 percent by the Tax "Reform" Act of 1969. Mineral production payments had been treated as economic interests in property since the courts established this principle in a landmark decision' rendered in 1940. During the years in which this treatment was allowed, a considerable number of regulations were adopted governing the application of these laws to petroleum transactions. These tax provisions significantly affected the value of petroleum properties and were naturally incorporated in the standard methods of evaluating them. As of Sept. 1, 1970, the new regulations, applicable to the revised statutory sections dealing with percentage depletion, carved-out and retained production percentage depletion, carved-out and retained production payments and the minimum tax, had not been issued. payments and the minimum tax, had not been issued. Although such regulations when issued could alter the impact of the new tax laws, I shall discuss the apparent effects of the statutory revisions upon the evaluation of petroleum properties. Percentage Depletion Percentage Depletion Depletion as applied to oil and gas reserves is the act or process of reducing the quantity of the exhaustible reserves of hydrocarbons. Since such depletion constitutes the using up of the capital represented by such reserves, the value of the reserves depleted by production is not income and therefore should not production is not income and therefore should not be subject to an income tax. The problem is how to value the produced reserves properly so as to permit a reasonable deduction from production revenues for this depletion of capital. The familiar history of the 27 1/2 percent rate of depletion allowance is that it was a frank compromise between the 25 percent and the 30 percent rates proposed by the two houses of the U. S. Congress. Less proposed by the two houses of the U. S. Congress. Less familiar is the fact that the establishment of this rate did away with a complex, cumbersome and litigious method of attempting to place a "windfall" value on hydrocarbon discoveries. Statutory Provisions The 1969 Act, which applies to all taxable years beginning after Oct. 9, 1969, made no significant changes in the language of the percentage depletion provisions of the income tax laws; the changes were provisions of the income tax laws; the changes were in the amounts allowed in lieu of cost depletion. In addition to the reduction from 27 1/2 to 22 percent in depletion allowance on production of oil and gas wells, there was a reduction from 23 to 22 percent on sulfur, uranium and many other U. S. minerals. Oil shale, gold, silver, copper and iron mined in the U. S. remain at 15 percent, but the depletion rate was reduced to 14 percent on foreign production of these items. Also reduced from 15 to 14 percent were bentonite, certain other clays, rock asphalt and metal mines. JPT P. 1475