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The dispersive behavior dynamics of clay determine soil characteristics such as permeability and aggregate stability, and, consequently, crop productivity. Soil dispersion is heavily influenced by the ionicity of clay–cation bonds and has been shown to be related to the net negative charge and pH of the system. Little work has been done, however, which considers these factors together, especially for K and Mg clays. The objective of the present study was to investigate the effect of changing pH on the dispersive behavior of Mg and K homoionic clays, in comparison to Ca and Na clays under equivalent pH conditions. The clay fractions used here were extracted from three soils and have distinctly different mineralogies. These clays were treated to become homoionic with regard to Na, K, Ca, and Mg. Excess salts were removed by dialysis and pH was adjusted to 3, 4, 5, 6, 7, 8, 9, 10, and 11 for all clays, except Mg (pH range 3–7). Clay dispersion-flocculation dynamics were investigated, and the net negative charge, pH, electrical conductivity (EC), and turbidity were measured. Mg has a similar but less flocculative effect than Ca, while K has a similar but less dispersive effect than Na, under similar pH conditions. The dispersive behavior of Na, K, Mg, and Ca homoionic clays was correlated well with the ionicity of clay–cation bonds at equivalent pH, with the degree of clay dispersion being explained by the pH, EC, ionicity, ζ-potential, and mean particle size of the clay–cation system. A predictive model for dispersion was developed with its applicability and limitations discussed.

Cation ratio of soil structural stability (CROSS) and exchangeable dispersive percentage (EDP) have been recently proposed to replace the traditional sodium absorption ratio (SAR) and exchangeable sodium percentage (ESP) for predicting soil structural stability, in conjunction with the electrolyte concentration. Both CROSS and EDP incorporate the dispersive effects as coefficients transforming K and Mg effects to equivalent Na, and flocculative coefficient transforming Mg effect to equivalent Ca. However, these coefficients are derived from the flocculating power of Na, K, Mg and Ca based on a limited number of soil clays. This study re-examines the flocculating power for a broad range of soil clays by analysing their critical flocculation concentrations (CFCs). Soil clays from 17 contrasting soils were separated and chemically treated into Na, K, Mg and Ca homoionic clays. Within the same cation treatment, there were significant differences among the measured CFC values, which can be related to their different clay mineralogy and co-existing materials in soil clays. The dispersive coefficients of K and Mg, as well as the flocculative coefficient of Mg, were seen to vary substantially in respect to the generalised values used in CROSS and EDP. The absolute errors between the specified CROSS and generalised CROSS as well as the specified EDP and generalised EDP have been calculated for the 95th percentile of possible cation concentrations. In terms of CROSS, the dispersive coefficient a[K] and flocculative coefficient b[Mg] both contribute to the absolute error, with a[K] having a greater influence than b[Mg]. In terms of EDP, the dispersive coefficient a[K] played the dominant role in causing absolute error between the specified EDP and generalised EDP, while the role of dispersive coefficient c[Mg] was not significant. The outcome of this work indicates that the soil-specific coefficients should be used to minimise the possibility of undue soil structural degradation, while the generalised coefficients are only applicable to a small range of outcomes.

Irrigation water containing appreciable amount of magnesium (Mg) is increasingly used in farming. However, studies on the effect of Mg on soil permeability and structural stability are limited and the results are contradicting. In this study, four soils of different dominant clay mineralogy, specifically kaolinite, illite and montmorillonite, were used to investigate the effect of Mg on saturated hydraulic conductivity (Ksat), interaction with organic carbon and soil clay dispersion and to compare to the effect of Ca. The soils were packed in columns and leached with four groups of either Ca-Ca, Ca-Mg, Mg-Mg or Mg-Ca solutions at the successive concentrations of 0.5, 0.25, 0.1, 0.05, 0.025, 0.01, 0.005, 0.001 and 0.0001 M, and finally with deionised water. Ksat was measured and leachates were assessed for dissolved organic carbon (DOC) and dispersion as turbidity. The leached soils were tested for aggregate stability, mechanical dispersion and zeta potential. This study showed that Mg had a disaggregation effect on soil structural stability. As compared to Ca, Ksat on Mg treated cores were lower over a wide range of concentrations, desorption of DOC and turbidity from Mg clay surface was higher, although the dispersion in leachates was insignificant under both Mg and Ca treatments. The effect of Mg treatment was more pronounced on smectic and illitic soils. The decrease in Ksat was related to Mg induced disaggregation, due to intra-crystalline swelling and/or the inter-crystalline swelling in Mg treated soil clays.

Using saline and sodic waters for irrigating agricultural lands has increased worldwide, which may cause adverse effects on soil porosity, structural stability and permeability. However, few studies have investigated the effect of clay swelling, dispersion and migration on the reduction of saturated hydraulic conductivity (Ksat) by analysing the total porosity and pore size change through the profile. In this study, two soils with contrasting mineralogy was used and packed at two different bulk densities (1.0 and 1.2 g cm−3). Soil columns were leached with three types of sodium adsorption ratio (SAR) solutions, i.e. good quality water (GQW), SAR 10 and SAR 50 solutions, before distilled water (low ionic strength) was leached through. The results indicated that the application of distilled water decreased Ksat for all soils, particularly in the initially sodic water treated columns. The Ksat of leaching with distilled water in low density columns were generally higher, but showed more degree of reduction than more compacted columns, mainly related to the high initial porosity and macropores that enabled dispersed clay to move through the soil column and out in the leachate. The application of distilled water significantly reduced the proportion of macro and mesopores, whereas increased the proportion of micropores in both soils, particularly for soil columns initially treated high SAR solutions. When the dispersed clay was trapped within the column, the depth of clay accumulation was affected by a combined effect of packing density, soil type and water quality.

MRS acquisition based on the blood oxygenation level dependent (BOLD) contrast mechanism was implemented at 3T to investigate the impact of a non-conventional spectral averaging scheme (determined by the number of RF excitations, NEX) on the dynamics of cerebral metabolism during neuroactivation. Using NEX=2, water and metabolite BOLD responses were compared to previous results from standard experiments.Spectra were recorded from the visual cortex of five healthy volunteers during single and block visual stimulations. The height, width and area of the spectral peaks were calculated (using SAGE v7) in order to estimate their percentage changes from baseline (representing the BOLD change) following visual stimulation. BOLD changes were statistically significant at a significance level of p0.05 by paired t-test.Significantly greater BOLD changes in all spectra were observed in the single than block stimulation (p0.05). The water resonance showed significant (p0.01) BOLD changes in all peak parameters in both paradigms. All metabolites showed significant increase in spectral height (p0.01) in the single paradigm, but none of them (except the height of Cho) showed significant BOLD response in the block paradigm. BOLD changes observed in the block paradigm were generally lower than reported changes.The time interval of 6s offered by NEX=2 during which each line of spectral data is recorded by the scanner is rather long, leading to some BOLD data loss particularly in a block experimental design.

This study quantitatively measured neonicotinoids in various foods that are common to human consumption. All fruit and vegetable samples (except nectarine and tomato) and 90% of honey samples were detected positive for at least one neonicotinoid; 72% of fruits, 45% of vegetables, and 50% of honey samples contained at least two different neonicotinoids in one sample, with imidacloprid having the highest detection rate among all samples. All pollen samples from New Zealand contained multiple neonicotinoids, and five of seven pollens from Massachusetts detected positive for imidacloprid. These results show the prevalence of low-level neonicotinoid residues in fruits, vegetables, and honey that are readily available in the market for human consumption and in the environment where honeybees forage. In light of new reports of toxicological effects in mammals, the results strengthen the importance of assessing dietary neonicotinoid intakes and the potential human health effects.

Parathyroid-hormone-related protein (PTHrP) contains several potential sites for proteolytic processing. Although there is considerable evidence for the existence of cleaved products in vivo, little is known about the post-translational processing of PTHrP. We have used purified kexin (Kex2) protease to identify which cleavage sites in recombinant PTHrP(1–141) might be of physiological significance. Cleavage products were identified by N-terminal sequencing. Kex2 preferentially cleaved PTHrP(l-141) carboxy to the triplet arginine site Arg-Arg-Arg21 with a Km of 3.3±1.7 μM and a kcatof 6±1.2 s−1. Substitution of alanine for Arg19 resulted in substantially reduced conversion, while no detectable cleavage occurred when alanine was substituted for either Arg20 or Arg21. In contrast, the degree of Kex2 cleavage at Arg21 in PTHrP(l-34) was lower. No detectable cleavage occurred in an unrelated synthetic peptide containing both double and triple arginine sites. Low levels of cleavage also took place carboxy to Lys-Arg97, Lys-Arg105, Arg-Arg106 and Thr-Arg108. Cleavage carboxy to Lys-Arg105, the best of these minor sites, occurred with a Km of 8.4±2.7 μM and a kcat of 0.8±0.2 s−1. These studies indicate that the preferred Kex2 cleavage site in PTHrP(l -141) is carboxy to Arg-Arg-Arg21, which effectively destroys its parathyroid-hormone-like biological activity. Cleavage of this site by Kex2-related mammalian convertases in vivo may be an important mechanism for full elaboration of the non-parathyroid-hormone-like paracrine actions of PTHrP in a tissue-specific manner.

The addition of high concentrations (0.1 - 10 mM) of ornithine or putrescine to EBV transformed human B lymphocyte or recombinant CHO rat or mouse myeloma serum-free suspension cultures resulted in most cases in an elevated product concentration. Under these conditions product formation was usually enhanced with little or no increase, and in many cases a decrease, in cell proliferation. KEY WORDS: Putrescine, ornithine, lymphocyte, CHO, myeloma, expression, recombinant, tPA, TIMP, antibody.

Estrogen administration during the luteal phase of the menstrual cycle resulted in rapid decline of progesterone levels in the peripheral plasma of 13 out of 16 cycles in macaque monkeys. In most instances, values returned to normal whether or not estrogen was continued. In more than half the animals, there was also a rise in plasma prostaglandin F.

While many radium applicators are available for the treatment of cervical cancer, the results obtained by a technic employed at Yale-New Haven Medical Center over the past ten years have proved sufficiently satisfactory to permit its description. Most intracavitary radium applicators used in the pelvis, consisting of an intrauterine tandem and some sort of vaginal applicator, are essentially modifications of two methods, the Paris-Manchester and the Stockholm. The intrauterine radium applicators are roughly similar in the two methods. The vaginal applicators differ in that the Paris corks, Manchester ovoids, or other colpostats based on these are bulkier than the Stockholm vaginal boxes, which are flat and are applied against the surface of the cervix. The Manchester technic was originally designed under the premise that certain injuries to the rectum were due to the high dose received at a point 2 cm from the vaginal fornix and 2 cm lateral to the cervical canal (Point A) as the result of occlusion of th...

dl-cis-Bisdehydrodoisynolic acid methyl ether proved a highly effective antifertility agent when administered postcoitally in the rabbit. Like other estrogens, the compound lowered the carbonic anhydrase levels in the pregnant rabbit uterus. The lowered values appeared tobe dose related. Administration of 2 mg/day orally for 6 days following midcycle mating in the macaque monkey resulted in only one pregnancy in 98 positive matings. When given in a dose of 25 mg/day for 3 days starting on the 24–33 day of the cycle there were two pregnancies out of 41 matings. These represent significantly lower pregnancy rates than encountered in untreated matings in the primate colony.

The postcoital antifertility activity of 17 natural and synthetic steroidal and non-steroidal compounds was evaluated in the rabbit. The estrogens tested (estrone ethinyl estradiol stilbestrol mestranol estradiol-17beta) were the most effective inhibitors of implantation while ORF-3858 was slightly less effective. RS-2196 and RS-229 had effects similar to those found in rats and were in the range of effectiveness of clomiphene and U-11100A. U-11555A had considerably less effect. Both norethindrone (less than 2% estrogen) and Sch-10015 inhibited implantation. Similar doses of testosterone and dihydrotesterone also inhibited implantation. Progesterone and chlormad inone acetate however failed to prevent implantation. All other compounds had sufficent uterotrophic activity to at least double uterine weight. Those compounds that were effective appeared to act directly on the endometrial implantation site.

The non-saponifiable fraction of the wax of Ulex europaeus L. contains β-amyrin, lupeol and β-sitosterol. Soyasapogenol C is obtained from an alcoholic extract of the plant.

The non-saponifiable fractions from petroleum and ether extracts of the bark of Sambucus nigra contain α-amyrenone, α-amyrin, betulin, oleanolic acid and β-sitosterol. This is the first recorded instance of α-amyrenone occurring in Nature.

6,7,8,9-Tetrahydro-3-hydroxy-2-methoxybenzocyclohepten-5-one has been converted into several bromoderivatives, acetals, and esters, and into 3-hydroxy-2-methoxybenzocyclohepten-5-one; further, its reduction with LiAlH4 has been compared with that of 6,7-dihydro-3-hydroxy-2-methoxybenzocyclohepten-5-one. A synthesis of 6,7-dihydro-3-hydroxy-8-hydroxycarbonyl-2-methoxybenzocyclohepten-5-one has been developed. Synthesis of 6,7,8,9-tetrahydro-4-methoxy-10H-cyclohepta[e]benzofuran-10-ones, 9-hydroxy-5,6-dihydro-8-methoxy-4H-benzo[6,7]cyclohept[1,2-c]pyrazole, 5,6-dihydro-9-hydroxy-8-methoxy-4H-benzo[3,4]cyclohept[1,2-d]isoxazole, and 10-hydroxy-6,7-dihydro-9-methoxybenzo[5,6]cyclohept[1,2-b]indole are described.

Oxidation of 11-oxolanostan-3β-yl acetate (1a) with selenium dioxide in acetic acid is accompanied by a C-nor-D-homo rearrangement of the steroid skeleton with aromatisation of ring D and formation of 9β-hydroxy-4,4,15-trimethyl-11-oxo-14(13→12)abeo-5α-cholesta-12,14,16-trien-3β-yl acetate (2a). Analogous aromatic products are obtained from 3β,7α- and 3β,7β-diacetoxy-11-oxolanostanes (1b and c), respectively, methyl 3β-acetoxy-11-oxo-25,26,27-trinorlanostan-24-oate (1e) and methyl 3β-acetoxy-24-methyl-11-oxolanostan-21-oate (1f), under the same conditions.

Describes an apparatus for the separation of volatile organic compounds by gas chromatography using oxygen or air as the carrier gas.