The expanded bed biofilter: combined nitrification, solids destruction, and removal of bacteria.

Developed for tertiary nitrification, this biofilter also removed carbonaceous BOD (cBOD) and (SS). Because the biofilter is expanded, it cannot clog, and therefore does not require backflushing; yet, it removed a significant proportion of the influent SS. This unanticipated capability was due to the activities of heterotrophic bacteria, protozoa, and metazoa (nematode and oligochaete worms). The expanded bed is an intensified process, which is based on natural immobilization of microbes to small support particles. Using glassy coke as the support material, an attached layer of microbes develops, forming particulate biofilms having a superficial surface area of 1 800 m2 m(-3)(expandedbed). Autotrophic nitritifiers (Nitrosomonas spp.) were detected in the biofilm using rRNA-based molecular methods and were likely responsible, at least in part, for reducing the ammonia concentration by up to 99% (to 0.1 mg L(-1)), while the other organisms reduced cBOD and SS by up to 56% and 62%, respectively. Furthermore, the influent concentrations of Escherichia coli, coliform and heterotrophic bacteria were reduced by over 80%. It thereby provides a single process solution for combined tertiary nitrification and solids removal. Operating the process to consistently achieve < 0.5mg NH3N L(-1) and at the same time removing a significant fraction of cBOD and SS, it can replace processes such as SAFs or NTFs followed by a sandfilter.     

A model-based evaluation of sorptive reactivities of hydrous ferric oxide and hematite for U(VI)

The sorption of uranyl onto hydrous ferric oxide (HFO) or hematite was measured by discontinuously titrating the suspensions with uranyl at pH 5.9, 6.8, and 7.8 under Pco2 = 10(-35)atm (sorption isotherms). Batch reactors were used with equilibration times up to 48 days. Sorption of 1 microM uranyl onto HFO was also measured versus pH (sorption edge). A diffuse double layer surface complexation model was calibrated by invoking three sorption species that were consistent with spectroscopic evidence for predominance of bidentate complexes at neutral pH and uranyl-carbonato complexes: > SOH:UO2OH(+1), (> SO)2: UO2CO3(-2), and (> SO)2:(UO2)3(OH)5(-1). The model was consistent with previously published isotherm and edge data. The model successfully predicted sorption data onto hematite, only adjusting for different measured specific surface area. Success in application of the model to hematite indicates that the hydrated surface of hematite has similar sorptive reactivity as HFO.     

Solubility of hematite revisited: effects of hydration

Measured pH and dissolved ferric iron concentration ([Fe(III)diss]) in contact with well-characterized hematite indicated an equilibrium with hematite immediately after synthesis, but [Fe(III)diss] increased with hydration time to be consistent with the predicted solubility of goethite or hydrous ferric oxide (HFO), hydrated analogues of hematite. X-ray diffraction did not detect structural modification of hematite after 190 days of hydration, but M?ssbauer spectroscopy detected hydration that penetrated several crystalline layers. When the hematite suspension was diluted with water, solids were invariably identified as hematite, but [Fe(III)diss] and pH indicated an equilibrium with goethite or HFO. This is the first experimental confirmation that the interfacial hydration of anhydrous hematite results in higher solubility than predicted by bulk thermodynamic properties of hematite. Correspondence of the results with previously published measurements and implications for environmental chemistry of ferric oxides are also discussed.     

Reduction of U(VI) by Fe(II) in the presence of hydrous ferric oxide and hematite: effects of solid transformation, surface coverage, and humic acid

Fe(II) was added to U(VI)-spiked suspensions of hydrous ferric oxide (HFO) or hematite to compare the redox behaviors of uranium in the presence of two different Fe(III) (oxyhydr)oxides. Experiments were conducted with low or high initial sorption density of U(VI) and in the presence or absence of humic acid (HA). About 80% of U(VI) was reduced within 3 days for low sorbed U(VI) conditions, with either hematite or HFO. The {Fe(3+)} in the low U(VI) experiments at 3 days, based on measured Fe(II) and U(VI) and the assumed presence of amorphous UO(2(s)), was consistent with control by HFO for either initial Fe(III) (oxyhydr)oxide. After about 1 day, partial re-oxidation to U(VI) was observed in the low sorbed U(VI) experiments in the absence of HA, without equivalent increase of dissolved U(VI). No reduction of U(VI) was observed in the high sorbed U(VI) experiments; it was hypothesized that the reduction required sorption proximity of U(VI) and Fe(II). Addition of 5mg/L HA slowed the reduction with HFO and had less effect with hematite. M?ssbauer spectroscopy (MBS) of (57)Fe(II)-enriched samples identified the formation of goethite, hematite, and non-stoichiometric magnetite from HFO, and the formation of HFO, hydrated hematite, and non-stoichiometric magnetite from hematite.     

Development of a semi-permanent mascara technology

Many women would like their mascara beauty benefits to be available all day, every day. One way to address this desire is through a semi-permanent mascara technology that provides full mascara benefits of long, dark beautiful lashes for multiple days. To date, products promising multi-day benefits have acted more as either 'lash dyes', providing a lash darkening benefit but failing to provide fullness and length, or waterproof mascaras that do not maintain the initial beauty look over multiple days. Here, a formulation approach is described for a mascara product that is designed to be abrasion resistant, flexible and insoluble in soap and water so that the initial beauty look is maintained for multiple days. The new semi-permanent formula technology uses rosinate polymers that have a superior combination of flexibility, abrasion resistance and water and surfactant resistance. Based on principles used by the paint industry for creating durable films, the levels of the polymers and other non-volatile ingredients are balanced such that the product forms a continuous polymer film on the eyelash. Cryo-SEM is used to demonstrate that the new semi-permanent formula technology forms a film different from those formed by current mascara products. A stretch test and rub test are used to demonstrate that the new semi-permanent formula technology has superior flexibility and abrasion resistance to current mascara products. Finally, a multi-day consumer study with daily imaging of the eyes is used to demonstrate the superior wear performance of the new semi-permanent formula technology in actual usage.     

Manganese fade control in open hearth rimmed steel

The occurrence of manganese fade in open hearth rimmed steel ingots is reviewed. The development of a new sampling method for determining chemical composition is described. A procedure for adding manganese to tail-end ingots and the effects of manganese ingot additions on ingot and product analysis are discussed.     

Effects of prior exercise on exercise-induced arterial hypoxemia in young women

Insulin-like growth factor binding proteins (IGFBP) proteases have been proposed to be involved in changes of serum IGFBP pattern during pregnancy. IGFBP-4 and -5 are degraded specifically by proteases in pregnancy serum in vitro, whereas IGFBP-3 proteolytic activity was also detected in nonpregnancy serum. To identify and characterize IGFBP proteases, human pregnancy serum was fractionated by size exclusion chromatography revealing IGFBP-4 protease activities in fractions coeluting with proteins of approximately 600-kDa and 50- to 100-kDa molecular mass. In both fractions, a predominant 50-kDa gelatinase was found, suggesting that parts of the gelatinase activity might aggregate or are complexed with other proteins forming a higher molecular complex. Hydroxyapatite chromatography and chromatofocusing of the 50- to 100-kDa serum fraction showed that the IGFBP-4 protease and the 50-kDa gelatinase activity were copurified. When the 50-kDa gelatinase-containing band was excised from the polyacrylamide gel, it exhibited IGFBP-4 proteolytic activity, resulting in the formation of 17- and 10-kDa fragments. [125I] IGFBP substrate zymography combined with fragment blotting showed that the 1,10-phenanthroline-sensitive 50-kDa protease activity purified by chromatofocusing also cleaved IGFBP-3 and -5. Other proteases detected in pregnancy serum fractions with Mr estimates of 79-, 30-, and 22-kDa degraded IGFBP-3 and -5 but not IGFBP-4. [125I] IGFBP-5 substrate zymography revealed that the 30-kDa IGFBP protease was inhibited by serine protease inhibitors. Whereas 1,10-phenanthroline inhibited the IGFBP proteolytic activity in the solution assay, serine protease inhibitors failed to affect proteolysis, indicating the predominant contribution of the metalloproteinase to IGFBP proteolysis. Tissue inhibitors of matrix metalloproteinases-1 and -2 revealed weak or no inhibition of IGFBP-4 and -5 proteolytic activity, whereas a hydroxamic acid-based inhibitor, potentially inhibiting disintegrin metalloproteases, completely prevented the proteolysis of IGFBPs. Whereas no specific immunoreactivity of the 50-kDa protein with antimatrix metalloproteinase-1, -2, -3, -9, or -13 antibodies was observed, antidisintegrin domain-specific antibodies bound to the 50-kDa gelatinase. These studies provide the first direct biochemical evidence that human pregnancy serum contains a 50-kDa IGFBP protease with properties of a soluble disintegrin metalloproteinase that appears to be potentially involved in regulating IGF bioavailability for placental and fetal growth.     

Wood Members Strengthened with Mechanically Fastened FRP Strips

The demand for a rapid technique to strengthen existing wood bridge structural elements is evident in military and civilian sectors. An experimental program was undertaken to evaluate the feasibility of increasing the flexural strength of Southern Pine wood members using mechanically fastened fiber-reinforced polymer (FRP) strips. Three control specimens and twelve composite members were fabricated using two FRP material types with varying fastener spacing and tested to failure. The experimental results show that the proposed strengthening technique induced a gradual failure of the composite members and increased ultimate moment, initial stiffness, and ductility over that found for the control specimens. Increased fastener spacing decreased member ultimate moment, initial stiffness, and ductility ratio. The moisture content of the wood material greatly affected the ductility ratio of the wood members.     

Pharmacokinetics and safety of single intravenous and oral doses of dolasetron mesylate in healthy women

The protease thrombin seems to play a central role in events following neural injury, whereby the enzyme can act, in concert with other molecules as a hormone or as a growth factor. In cells derived from the nervous system, thrombin induces changes in morphology and proliferation. The signalling mechanisms involved in these thrombin-activated processes are still unclear. In the present study we investigated Ca2+ signals in fura-2 loaded rat astrocytes in primary culture. Brief stimulation of astrocytes with thrombin induced a dose-dependent transient elevation of [Ca2+]i, best fitted by a double-sigmoidal curve giving two EC50 values of 3 pM and 150 pM. Continuous superfusion of cells with thrombin induced Ca2+ responses with three different types of kinetics. In 48% of the cells tested a single transient rise superimposed with fast fluctuations of [Ca2+]i was seen. The following complex long-term changes of [Ca2+]i, dependent on the presence of the agonist thrombin, were observed: i) a biphasic [Ca2+]i elevation, characterized by an initial peak followed by a sustained plateau phase (in 43% of the cells) and ii) oscillations of [Ca2+]i (in 9% of the cells). The observed Ca2+ responses were inhibited by the phospholipase C (PLC) inhibitor U-73122 and the thrombin inhibitor protease nexin-1/glia-derived nexin. The synthetic thrombin receptor activating peptide could mimic the thrombin-induced changes of [Ca2+]i. In astrocytes in Ca2+-free medium, thrombin induced a sharp single transient Ca2+ rise, without superimposed fluctuations. After depletion of intracellular Ca2+ stores with thapsigargin the Ca2+ response to thrombin was diminished or completely suppressed indicating that thrombin induces the release of Ca2+ from intracellular stores. During long-term Ca2+ responses, omission of extracellular Ca2+ resulted in a reversible interruption of the signal. In conclusion our results demonstrate that thrombin by activation of its plasma membrane receptor induces through activation of PLC different types of Ca2+ responses. The complex Ca2+ signals are generated by an interplay of InsP3-mediated Ca2+ release from intracellular stores and Ca2+ entry across the plasma membrane.     

A volume-dependent apneic threshold during NREM sleep in the dog

We determined the causes of central apnea that commonly follow the hyperpnea resulting from brief airway occlusion during non-rapid-eye-movement (NREM) sleep. Ventilation and end-tidal gases were measured before, during, and after 214 trials of 15-20 s of tracheal occlusion in three dogs during NREM sleep. Airway occlusion was accompanied by progressive increases in inspiratory effort and was followed by transient one- to four-breath hyperapneas, with subsequent central apnea [3-15 times eupneic control expiratory duration (TE)] in 62% of occlusion trials. Significant TE prolongation after hyperventilation did not occur until tidal volume (VT) was three times greater than control; i.e., there was a volume-dependent apneic threshold. Transient electroencephalogram arousal at the end of the occlusion often augmented VT, thereby contributing to the subsequent central apnea; however, arousal was not required for the apnea to occur. Significant transient hypocapnia (up to -12 Torr arterial PCO2) commonly occurred after release of airway occlusion but was not closely correlated with the length of central apnea. During vagal blockade, after release of airway occlusion, significant transient hyperventilation occurred but at VT < 40% greater than control, and TE prolongation was markedly reduced. In summary, after release of airway occlusion in NREM sleep, 1) VT greater than three times eupnea was necessary to cause central apnea, 2) transient arousal at the termination of airway occlusion caused longer apneas by augmenting VT, and 3) transient hypocapnia per se made a significant but minor contribution to the postocclusion central apnea.