Acid Release from an Acid Sulfate Soil Sample Under Successive Extractions with Different Extractants

An acid sulfate soil sample was successively extracted with deionized water, 1 mol L-1 KCl and 0.000 5 mol L-l Ca(OH)2 solutions. The results showed that only very small amounts of acidity were extracted by deionized water, possibly through slow jarosite hydrolysis. Acid release through jarosite hydrolysis was greatly enhanced by Ca(OH)2 extraction at the expense of the added OH- being neutralized by the acid released. Successive extraction of the sample with KCl removed the largest amounts of acidity from the sample. However, it is likely that the major form of acidity released by KCl extraction was exchangeable acidity. The results also show the occurrence of low or non charged Al and Fe species in water and Ca(OH)2 extracts after first a few extractions. It appears that such a phenomenon was related to a decreasing EC value with increasing number of extractions.

The Action of p-Synephrine on Lipid Metabolism in the Perfused Rat Liver

p-synephrine and p-octopamine were found to increase lipolysis in adipocytes. The present study approaches the question if these compounds, natural products of the bitter orange (Citrus aurantium fruit), increase lipolysis and fatty acid oxidation in the liver. Experiments were done in the perfused rat liver. Non-recirculating hemoglobin-free perfusion was done using the Krebs/ Henseleit-bicarbonate buffer (pH 7.4) as perfusion fluid. Both p-synephrine and p-octopamine, at the concentrations of 100 μM, were found to stimulate the hepatic triacylglycerol lipase by 40% and 51%, respectively. These seem to be the maximal stimulations possible in the liver. In the perfused liver, p-synephrine, when present at an initial concentration of 500 μM, was able to increase the non-esterified fatty acid release after one hour of recirculating perfusion. The effects of p-synephrine on the oxidation of exogenously supplied [1-14C]octanoate and [1-14C]oleate were minimal. Only oxygen uptake, already stimulated by octanoate or oleate, was additionally increased by the infusion of p-synephrine. These results contrast with those obtained in a previous study with p-octopamine, which increased the production of 14CO2 from both [1-14C]octanoate and [1-14C]oleate. Apparently only the oxidation of endogenous fatty acids is stimulated by p-synephrine. On the other hand, both p-synephrine and p-octopamine stimulate the hepatic triacylglycerol lipase to a much lesser extent than the adipocyte lipase. It can be concluded that p-synephrine affects much more carbohydrate metabolism in the liver than lipid metabolism.

Assessment of Potential Nutrient Release from Phosphate Rock and Dolostone for Application in Acid Soils

Finding alternative local sources of plant nutrients is a practical, low-cost, and long-term strategy. In this study, laboratory column experiments were conducted in a completely randomized design to evaluate the feasibility of using phosphate rock and dolostone as fertilizers or acid-neutralizing agents for application in tropical acid soils. The dissolution rates of different particle-size fractions(0.063–0.25, 0.25–0.5, and 0.5–2 mm) of both rocks were studied by citric acid solution at p H 4 and 2 and water, with extraction times of 1, 3, 5, 7, 12, 24, 72, 144, 240, and 360 h. The results showed that the dissolution of both rocks depended on the particle size,leaching solution, and extraction time. The dissolution rate of rock-forming minerals increased as the specific surface area increased,corresponding to a decrease in particle size. In all cases, the release kinetics was characterized by two phases: 1) a first stage of rapid release that lasted 24 h and would ensure short-term nutrient release, and 2) a second stage of slow release after 24 h, representing the long-term nutrient release efficiency. Both rocks were suitable as slow-release fertilizers in strongly acid soils and would ensure the replenishment of P, Ca, and Mg. A combination of fine and medium particle-size fractions should be used to ensure high nutrient-release efficiency. Much work could remain to determine the overall impact of considerable amounts of fresh rocks in soils.

Novel liver-specific nitric oxide(NO) releasing drugs with bile acid as both NO carrier and targeting ligand

Novel liver-specific nitric oxide（NO） releasing drugs with bile acid as both the NO carrier and targeting ligand were designed and synthesized by direct nitration of the hydroxyl group in bile acids or the 3-Ohydroxyl alkyl derivatives,with the intact 24-COOH being preserved for hepatocyte specific recognition.Preliminary biological evaluation revealed that oral administrated targeted conjugates could protect mice against acute liver damage induced by acetaminophen or carbon tetrachloride.The nitrate level in the liver significantly increased after oral administration of 1e while nitrate level in the blood did not significantly change.Co-administration of ursodeoxycholic acid（UDCA） significantly antagonized the increase of nitrate in the liver resulted by administration of 1e.

Doxorubicin-loaded PLGA Microparticles with Internal Pores for Longacting Release in Pulmonary Tumor Inhalation Treatment

Doxorubicin（DOX） loaded poly（lactic-co-glycolic acid）（PLGA） microparticles with internal pores（MP-D） were developed for long-acting release in pulmonary inhalation treatment. The PLGA microparticles exhibited favorable aerodynamic properties for pulmonary delivery. In vitro drug release profile suggested that MP-D have the advantage of long-term maintenance of drug concentrations. MTT assay demonstrated the in vitro anti-tumor efficiency of the DOX loaded PLGA microparticles. Furthermore, melanoma lung metastasis model was established to determine the in vivo antitumor efficiency. The mice treated with MP-D showed significantly fewer lesions than the untreated ones. The survival analysis indicated that MP-D prolonged the survival time of tumor-bearing mice. These results suggested that DOX loaded PLGA microparticles with internal pores have the potential to be used as long-acting release carriers in clinical lung cancer treatment.

Improved thromboresistance and analytical performance of intravascular amperometric glucose sensors using optimized nitric oxide release coatings

In this work, nitric oxide （NO） release coatings designed for intravenous amperometric glucose sensors are optimized through the use ofa polylactic acid （PLA） layer doped with a lipophilic diazeniumdiolated species that releases NO through a proton-driven mechanism. An Elast-Eon E2As polyurethane coating is used to both moderate NO release from the sensor surface and increase the sensor＇s linear detection range toward glucose. These sensors were evaluated for thromboresistance and in vivo glucose performance through implantation in rabbit veins. By maintaining NO flux on a similar scale to endogenous endothelial cells, implanted glucose sensors exhibited reduced surface clot formation which enables more accurate quantitative glucose measurements continuously. An in vivo time trace of implanted venous sensors demonstrated glucose values that correlated well with the discrete measurements of blood samples on a benchtop point-of-care sensor-based instrument. The raw measured currents from the implanted glucose sensors over 7 h time periods were converted to glucose concentration through use of both a one-point in vivo calibration and a calibration curve obtained in vitro within a bovine serum solution. Control sensors, assembled without NO release functionality, exhibit distinctive surface clotting over the 7 h in vivo implantation period.