Characteristic corrosion resistance of nanocrystalline TiN films prepared by high density plasma reactive magnetron sputtering.

Nanocytalline TiN films were deposited on non-alkali glass and Al substrates by reactive DC magnetron sputtering (DCMS) with an electromagnetic field system (EMF). The microstructure and corrosion resistance of the TiN-coated Al substrates were estimated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. All the TiN films shows that they have a (111) preferred orientation at room temperature. TiN films deposited on Al substrate using only DCMS 400 W showed a sheet resistance of 3.22 x 10-1 omega/symbol see texts (resistivity, 3.22 x 10-5 omegacm). On the other hand, a relatively low sheet resistance of 1.91 x 10-1 omega/symbol see text (1.91 x 10-5 omegacm) was obtained for the dense nanocrystalline TiN film deposited on Al substrate using DCMS 375 W+ EMF 25 W, indicating that the introduction of an EMF system enhanced the electrical properties of the TiN film. TiN films deposited on Al substrate at 400 degreesC had a (200) preferred orientation with the lowest sheet resistance of 1.28x10-1 omega/symbol see texts (1.28 x 10-5 omegacm) which was attributed to reduced nano size defects and an improvement of the crystallinity. Potentiostatic and Potentiodynamic tests with a TiN-coated Al showed good corrosion resistance (l/corr, = 2.03 microA/cm2, Ecorr = -348 mV) compared to the uncoated Al substrate (/corr = 4.45 microA/cm2, Ecorr = -650 mV). Furthermore, EMF system showed that corrosion resistance of the TiN film also was enhanced compared to DCMS only. For the TiN film deposited on Al substrate at 400 degreesC, corrosion current and potential was 0.63 micro/cm2 and -1.5 mV, respectively. This improved corrosion resistance of the TiN film could be attributed to the densification of the film caused by enhancement of nitrification with increasing high reactive nitrogen radicals.

System design and treatment efficiency of a surface flow constructed wetland receiving runoff impacted stream water.

This study reported the efficiency of a free water surface flow constructed wetland (CW) system that receives runoff impacted stream water from a forested and agricultural watershed. Investigations were conducted to examine the potential effect of hydraulic fluctuations on the CW as a result of storm events and the changes in water quality along the flow path of the CW. Based on the results, the incoming pollutant concentrations were increased during storm events and greater at the near end of the storm than at the initial time of storm. A similar trend was observed to the concentrations exiting the CW due to the wetland being a relatively small percentage of the watershed (<0.1%) that allowed delays in runoff time during storm events. The concentrations of most pollutants were significantly reduced (p < 0.05) except for nitrate (p = 0.5). Overall, this study suggests that the design of the system could feasibly function for the retention of most pollutants during storm events as the actual water quality of the outflow was significantly better by 21-71% than the inflow and the levels of pollutants were reduced to appreciable levels.

High affinity binding and regulatory actions of dexamethasone-type I receptor complexes in mouse brain.

It is often implied that the various molecular, physiological, and behavioral responses to the glucocorticoid dexamethasone (DEX) are mediated in brain exclusively via the interactions of this synthetic steroid with the classical glucocorticoid (type II) receptor. The results reported in this study, however, suggest this generalization may, at least for the female mouse, be too restrictive. In the first experiment we compared the efficacy of the mineralocorticoid aldosterone (ALDO) with that of DEX to measure the classical mineralocorticoid (type I) receptor in brain cytosol. Since both of these steroids also bind to type II receptors, our assays included the type II receptor-selective ligand, RU26988. Whereas the specific binding of ALDO to type I receptors was largely unaffected by a 10-fold increase in the concentration of RU26988 (50- vs. 500-fold excess), there was a dramatic reduction in the specific binding of DEX. In a follow-up experiment, Scatchard analyses were used to confirm the differential affinity of RU26988 for DEX- vs. ALDO-type I receptor-binding sites and to reveal that the affinity of type I receptors for DEX (Kd approximately 0.83 nM) was nearly as high as it was for ALDO (Kd approximately 0.46 nM). A series of competition studies indicated that the competitive affinity (Kdc) of DEX for the ALDO-binding site was equivalent to the Kd computed in the saturation analyses, thus suggesting that the high affinity binding sites for DEX and ALDO on type I receptors may be equivalent or at least overlapping. The binding of DEX to these high affinity sites may prove to be important, since the systemic administration of this steroid was found to down-regulate both type I and type II receptors in a number of brain regions. Because coadministration of the type I receptor antagonist RU26752 was shown to block these actions on type I, but not type II receptors, the formation of the DEX-type I receptor complex appears to be required for DEX-induced type I receptor down-regulation. An analysis of the in vitro efficacy of ALDO- vs. DEX-type I receptor transformation suggests that whereas there is a significant increase in the binding of both complexes to DNA-cellulose after treatment with thiocyanate, there is also a dramatic decrease in the stability of DEX- but not ALDO-type I receptor binding. We contend that it is this decrease in binding stability that mediates the DEX-induced down-regulation of type I receptors.(ABSTRACT TRUNCATED AT 400 WORDS)

Preparative study on the isolation of single sarcomeres from rabbit skeletal muscle.

Single sarcomeres were prepared from fresh rabbit myofibrils by digestion with a calcium-activated factor (CAF). The rabbit single sarcomere has functional properties quite similar to those of single sarcomeres obtained from chicken muscle by a usual method. Thus it was found that the single sarcomeres obtained by CAF digestion were useful as a muscle model, though they were not completely intact.

Treatment of mouse brain cytosol with dextran-coated charcoal and high salt does not reveal a new glucocorticoid binder.

Incubation of steroid-free whole mouse brain cytosol from adrenalectomized-ovariectomized mice with saturating concentrations of tritiated dexamethasone was found to label all Type I as well as all Type II adrenocorticosteroid receptors. The quantitative and brain regional distribution of residual dexamethasone binding in cytosols pre-treated with dextran-coated charcoal (DCC) and 300 mM KCl was indistinguishable from that for tritiated aldosterone-Type I receptor complexes under the same conditions. We therefore conclude that the dexamethasone binding sites remaining after DCC and KCl treatment of steroid-free brain cytosol are due to the presence of Type I receptors. The differential sensitivity of Type I and Type II receptors to the DCC/KCl treatment paradigm may be useful in the purification of Type I receptors.