Robust, small diameter hydrophilic nanofibers improve the flux of ultrafiltration membranes

In this study, we systematically investigated the flux performance of ultrafiltration (UF) membranes functionalized with randomly-accumulated nanofibers. By electrospinning nanofibers from hydrophobic polysulfone (PSf) and hydrophilic cellulose (CL), we were able to explore the role that bulk nanofiber (NF) layer thickness, individual NF diameter, and intrinsic chemistry have on composite membrane flux. Additional parameters that we systematically tested include the molecular weight cut-off (MWCO) of the base membrane (10, 100, and 200 kDa), flow orientation (cross-flow versus dead-end), and the feed solution (hydrophilic water versus hydrophobic oil). Structurally, the crosslinked PSf nanofibers were more robust than the CL nanofibers, which lead to the PSfNF-UF membranes having a greater flux performance. To decouple the structural robustness from the water affinity of the fibers, we chemically modified the PSf fibers to be hydrophilic and indeed, the flux of these new composite membranes featuring hydrophilic crosslinked nanofibers were superior. In summary, the greatest increase in flux performance arises from the smallest diameter, hydrophilic nanofibers that are mechanically robust (crosslinked). We have demonstrated that electrospun nanofiber layers improve the flux performance of ultrafiltration membranes.

Factors affecting soil acidification under legumes. III. Acid production by N2 -fixing legumes as influenced by nitrate supply

Leaching of nitrate through soil profiles is a major cause of soil acidification. Legume species differ in their ability to take up nitrate (NO₃ ^- ) and in the degree to which soil NO₃ ^- impairs legume nodulation and N₂ fixation. This pot experiment examined species variation in N₂ fixation and acid production in grain legumes grown for 6 wk on a sandy soil with Ca(NO₃ )₂ added at 0-56.7 mg N kg^-1 soil. The eight legumes studied were Lupinus angustifolius ('Gungurru'), Lupinus albus ('Kiev mutant'), Lupinus luteus ('Teo'), Cicer arietinum (Selection T1587), Pisum sativum ('Dundale' and 'Wirrega'), Vicia faba ('Fiord') and Lathyrus sativus (Selection 453). While number of nodules was not significantly affected by treatment with NO₃ ^- , increasing supply of NO₃ ^- decreased nodule mass, with P. sativum'Wirrega' being most sensitive and C. arientinum and V. faba least sensitive. The concentrations of nitrogen in plants generally decreased as the supply of NO₃ ^- increased. Increasing supply of NO₃ ^- decreased the percentage of N₂ fixation, most significantly in L. sativus and least in L. albus. In the absence of added NO₃ ^- , the amounts of H⁺ produced per unit biomass (specific acid production) differed by as much as 2.2-fold among the species, with C. arientinum generating most H⁺ , followed by L. angustifolius, L. luteus, L. albus, V. faba, L. sativus, P. sativum'Dundale' and P. sativum'Wirrega'. This species variation was even greater at higher NO₃ ^- supply. In the presence of NO₃ ^- at up to 14.2 mg N kg^-1 , acid production by these legumes correlated well with uptake of excess cations but not with the concentration of nitrogen in plants. For all species, release of H⁺ declined with increasing supply of NO₃ ^- , decreasing most in L. sativus and least in C. arientinum. The results suggest that there might be scope for selecting grain legume species in order to minimize soil acidification by decreasing leaching of NO₃ ^- .

Recovery from alcoholism: a spiritual journey

The purpose of this study was to discover the internal aspects of change in persons who are doing well living without alcohol. The heuristic research method, a qualitative phenomenological design, was used to investigate the experience of recovery. Eight recovering alcoholics were interviewed in depth. The process of recovery reflected a mythological journey comprising a departure from the shadowland of drinking, initiation into the world of sobriety, and knowledge gained along the way. New adaptive strategies were acquired, including strengthening the will, training the mind, and exercising spiritual qualities in one's daily life. The profile of doing well in recovery also reflected self-acceptance and an ongoing search for connecting with the transpersonal realm.

The response of wheat tops and roots grown in a leaching environment to rates of nitrogen added as calcium nitrate or organic residues containing 1, 2 or 6% nitrogen

Wheat was grown under leaching conditions in a glasshouse in columns of a loamy sand soil to which nitrogen had been added in the form of calcium nitrate or organic materials containing 1, 2 or 6% nitrogen. All materials were added at a range of rates calculated on an elemental nitrogen basis, so that comparisons could be made between materials at the same level of nitrogen addition. The amount of mineral nitrogen in the soil profile 4 weeks after seeding increased with the addition of each of the sources except for the 1% nitrogen organic material which had no effect. Addition of calcium nitrate caused the greatest increase of mineral nitrogen, but did not result in the greatest plant growth because of less efficient nitrogen uptake associated with leaching. At 7 weeks after seeding, nitrogen stress, as indicated by the nitrogen content of the plant tops, had increased more where the 2 and 6% nitrogen organic materials were added than where calcium nitrate was added. This trend was also reflected in changes in the root to shoot ratios, and was the result of roots catching up with leaching nitrate from the calcium nitrate. In the columns treated with organic material, root profiles at 7 weeks after seeding showed enhanced growth at the surface, where mineralization of the added materials was occurring. Where calcium nitrate was added, a bulge in the root profile occurred at depth, associated with the leached nitrate.

Granular reactive apatite rock phosphate is not an effective phosphorus fertilizer in the short term on lateritic soils in south-western Australia

The effectiveness, as a phosphate fertilizer, of granular reactive rock phosphate (carbonate substituted apatite from North Carolina, U.S.A.), granular triple superphosphate and partly powdered Duchess non-reactive rock phosphate (low carbonate apatite from north-eastern Australia) was compared in three field experiments on different soil types in different climatic regions of south-western Australia. Calciphos (finely ground calcined crandallite rock phosphate from Christmas Island) was included in one experiment. The rock phosphates were incorporated into the soil and their effectiveness was compared with both topdressed and incorporated superphosphate. Different species were grown at each site (barley, triticale and subterranean clover). As determined on the basis of relative amounts of fertilizer required for constant yield, the effectiveness of all the rock phosphates relative to incorporated superphosphate was very low at each site throughout the growth of each species. Fertilizer effectiveness of rock phosphates was about one-fifth that of superphosphate for barley, and one-tenth for triticale and clover. The maximum yield obtained from rock phosphate was generally 88-100% that obtained from superphosphate. Incorporation did not greatly affect the effectiveness of superphosphate.

Effect of deep ripping, the previous crop, and applied nitrogen on the growth and yield of a wheat crop

The response, to ripping and nitrogen application, of a wheat crop which has grown after a 1 -year crop of wheat, lupins and pasture was measured in terms of tops growth, nitrogen uptake, rooting depth and grain yield. Although there were limitations to the data set used, a graphical method demonstrating separation of the effects of treatment on soil nitrogen status and nitrogen use efficiency was compared using the classical analysis of variance. Ripping increased the rate of root extension and this caused the more efficient use of fertiliser nitrogen early in the season. Compensatory nitrogen uptake took place late in the season on the unripped plots. However, grain and tops yields were significantly greater on the ripped plots. The major effect of a previous crop of lupins was to increase the nitrogen status of the plots, although early in the season the efficiency of nitrogen use was also improved. A dry finish to the season turned a statistically non-significant ripping x nitrogen x species interaction for tops growth into a significant negative interaction for grain yield.

Long-term availability of phosphorus from calcined rock phosphate compared with superphosphate

The phosphorus supply from single dressings of three rates of superphosphate and Christmas Island C-grade ore calcined at either (a) 500�C or (b) 900�C were compared in a long-term field trial by measuring (i) bicarbonate-extractable phosphorus and (ii) dry weight of tops of a subterranean clover based pasture in spring each year. For superphosphate, the bicarbonate-extractable phosphorus decreased with time, whereas for the two calcined products, the amount of bicarbonateextractable phosphorous, although initially low, increased slightly with time. As measured by herbage yield, the effectiveness of superphosphate decreased from the first to the second year and thereafter changed little with time. The effectiveness of the two calcined products tended to increase with time. Superphosphate was much more effective than the two calcined products throughout the trial. The effectiveness of both calcined products were similar, despite the fact that the fertilizers differed in their proportions of total phosphorus which was soluble in neutral ammonium citrate. The bicarbonate soil test did not always predict the same future pasture production for the three phosphorus sources, indicating that different soil test calibration curves are needed for each source.

Effect upon the EEG of acute injury to the brain stem activating system

The effect upon the EEG in the unanesthetized "ecéphale isolé" of acute brain stem lesions in a position to involve the ascending reticular activating system has been studied. Elimination of the bulbar segment was without marked effect. Some synchronization followed elimination of the pons, but the most pronounced and prolonged changes occurred as a result of mesencephalic transection, or of discrete injury to the midbrain tegmentum or basal diencephalon, following which the EEG activation pattern of low voltage fast activity was reduced or abolished and the cortical record became dominated by recurring bursts or spindles of high voltage slow waves like those of normal sleep or barbiturate anesthesia. Bursts could be recorded from the intralaminar and other nuclei of the thalamus and these thalamic bursts were abolished by acute decortication. Conversely, cortical bursts were abolished by acute thalamic lesions. Possible interrelations of these regions in this activity is discussed. These results offer an explanation for the clinical observation of somnolence following basal injury to the brain, and suggest that a maintained influence of the ascending brain stem activating system underlies wakefulness, while absence of this influence precipitates sleep.