Physiological and behavioral responses of stonefly nymphs to enhanced limestone treatment of acid mine drainage

A new acid mine drainage (AMD) treatment system uses pulsed, fluidized beds of limestone, and carbon dioxide pretreatment of influent AMD, to enhance limestone neutralization of AMD. We conducted laboratory studies to evaluate the behavior and physiology of larval stoneflies (Pteronarcys proteus, Plecoptera) exposed to effluents produced by the treatment system. Survival, sodium balance, drift, and feeding responses by P. proteus to treated and untreated AMD were examined. P. proteus nymphs exhibited significant losses of whole body sodium in exposures to untreated AMD. Nymphs exposed to treated effluents experienced no loss of whole-body sodium. Nymphs exposed to untreated AMD showed elevated drift rates and depressed feeding rates relative to those of nymphs exposed to treated AMD, and to AMD-free controls. No significant differences in feeding or drift behavior occurred between nymphs exposed to treated effluents and those exposed to AMD-free controls. The treatment system, with and without CO2 pretreatment, provided water that was not toxic to the test animals, and that allowed normal behavioral and physiological function.     

Electrochemiluminescence of copper(I) bis(2,9-dimethyl-1,10- phenanthroline)

The electrochemical and electrochemiluminescence (ECL) properties of Cu[dmp]2+ (dmp = 2,9-dimethyl-1,10-phenanthroline) have been investigated. ECL has been observed for Cu(dmp)2+ in aqueous, nonaqueous, and mixed solvent solutions using tri-n-propylamine as an oxidative-reductive coreactant. The ECL intensity peaks at potential corresponding to oxidation of both the coreactant and Cu(dmp)2+. The peak potential corresponding to maximum ECL emission is approximately 500 mV more anodic than corresponding oxidative peak potentials, indicating that the ECL emission may be due to the formation of either the *Cu(dmp)2+ metal-to-ligand charge-transfer excited state or an excited-state product of Cu(dmp)2+ oxidation. ECL efficiencies (phiecl = photons generated per redox event) are solvent-dependent (phiecl (CH3CN) > phiecl (50:50 (v/v) CH3CN:H20) > phiecl (H2O)) and correspond fairly well with photoluminescence efficiencies. Increased ECL efficiencies (> or = 50-fold) are observed in the presence of the nonionic surfactant Triton X-100.     

Effect of eicosapentaenoic acid on the proliferation and incidence of apoptosis in the colorectal cell line HT29

Fish oil has been shown to reduce the induction of colorectal cancer in animal models by a mechanism which may involve suppression of mitosis, increased apoptosis, or both. We used the human colonic adenocarcinoma cell line HT29 to explore the effects of the long-chain n-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) on cell proliferation and death in vitro. Cells were cultured in media containing EPA at 5, 10, and 15 μg/mL. Cell number and thymidine incorporation were used to quantify proliferation, and cell cycle effects were studied using flow cytometry. Gel electrophoresis, annexin-V binding, and morphological criteria were used to characterize apoptosis. Adherent cells and freely floating detached cells were treated as two distinct populations. In the presence of EPA at 10 and 15 μg/mL there was a marked reduction in the growth rate of adherent HT29 colonies, owing to an increased detachment of adherent cells. After treatment with 10 or 15 μg/mL EPA the proportion of adherent cells in S-phase increased, indicating either a block in late S-phase or early G2. Floating cells showed evidence of extensive DNA cleavage, but the proportion of floating cells with sub G0 DNA content declined on treatment with 10 or 15 μg/mL EPA even though the number of floating cells increased. We conclude that EPA does not inhibit mitosis of adherent cells, but increases the rate at which they become detached from the substrate, probably at an early stage in the initiation of apoptosis. This mechanism may be analogous to “anoikis”, or induction of apoptosis in response to loss of cell contact, and may contribute to the anticarcinogenic effects of fish oil in vivo.     

Calcium hydroxide attack on rocks

Nineteen samples of Australian rocks of various types, all containing feldspars, were examined for their reactivities in calcium hydroxide solution at 50°C following the procedures used by van Aardt and Visser (Cem.Concr.Res.$\text{1}$,643,1977). The results confirm the previous findings for basalts and granites that these rocks, in powdered form, release large quantities of alkalies as a result of the breakdown of feldspars in the rock. However, the postulate that the high reactivity of feldspars could lead to alkali-aggregate reaction in highly feldspathic rocks is not consistent with the known performance of basalts and granites as concrete aggregates in Australia. Of the other rock types examined, the reactivities followed in the order: hornfels > sandstones > siltstones. Samples of deleteriously reactive sedimentary rocks included for examination did not show an unusual release of alkalies after either short or long times of digestion.     

Effect of drought on occurrence ofaspergillus flavus in maturing peanuts

Florunner peanuts were grown in experimental plots with soil moisture and soil temperature modified during the last third of the growing period to produce drought, drought with cooled soil, irrigated and irrigated with heated soil treatments. Twice each week, beginning 97 days after planting, random samples were harvested and maturities of individual pods were determined without destroying pod integrity. The nature and quantity of the microflora associated with the pods and kernels were subsequently assessed. Drought and lower soil temperature resulted in maturity distributions containing higher proportions of immature pods. On peanuts with no visible damage to the pod or kernel, colonization byAspergillus flavus was more frequent in immature than mature kernels. Drought stress increased the incidence ofA. flavus and irrigation decreased it, except when soil temperatures were modified.A. flavus infestation was greatly increased at all maturity levels by pod damage.     

Acoustic emissions from polycrystalline ice

The acoustic emission response from fine-grained polycrystalline ice subjected to constant compressive loads was examined. A number of tests were conducted with the nominal stress ranging from 0.8 to 3.67 MPa at a temperature of ?5°C. The acoustic emission response was recorded and the data are presented with respect to time and strain. The source of acoustic emissions in ice is considered in terms of the formation of both microfractures and visible fractures that develop without catastrophic failure of the ice. A model to describe the acoustic emission response is developed.     

What's new in speech perception? The research and ideas of William Chandler Bagley, 1874–1946.

Describes W. C. Bagley's (1900, 1901) research on the relation between sound and meaning in human speech perception. Using phonograph cylinders, Bagley presented Ss with spoken words, either individually or in sentences, that had been pronounced with a missing consonant sound. Ss, who were instructed to report only what they had heard, often restored words to their original form (i.e., heard the words as if they had been spoken correctly). Restorations were determined by the position of the missing sound in the word and the position of the word in the sentence. The pattern of results observed by Bagley and his conclusions about human speech perception find remarkable parallels in contemporary psycholinguistics. For example, Bagley explained his results in terms of the critical role of context in speech perception and the sequential use of sound in spoken-word recognition. Some of the main results of Bagley's research are compared to those obtained in more recent experiments. It is concluded that many of the most important insights about spoken-word recognition were first offered by Bagley. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Tensile yield in poly(4-methyl pentene-1)

Uniaxial tension tests to the yield point were performed on a crystalline polymer, poly(4-methyl pentene-1) (PMP) as a function of temperature from 21° to 200°C at a strain rate of 2 min^?1. After testing, the specimens showed considerable stress whitening as a result of microvoid formation. Yield energy was found to be a linear function of temperature extrapolating to zero at the melting point (240°C). Thus, the behavior of this crystalline polymer is similar to that of glassy polymers, but with the melting temperature, rather than the glass transition temperature, as the reference point. The ratio of thermal to mechanical energy input to produce yielding is an order of magnitude smaller for PMP than it is for glassy polymers. The ratio of yield stress to Young's modulus is about 0.02, which is typical for polymers. Yield stress is a linear function of log strain rate, which implies that yielding can be described as a segmental flow rate process in which the applied stress biases the activation energy. The activation volume is on the order of 20 monomer unit volumes and increases as the temperature increases. The activation energy is 19 kcal/mol.