It is suggested that the new self-adhesive resin cements exhibited a favorable bonding capability and mechanical properties.

Recent studies have indicated that chronic administration of iV"-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide (NO) synthesis, produces marked hypertension. Although the mechanism of this form of hypertension is not well understood, several studies have demonstrated that sympathetic nerve activity is at least acutely elevated after L-NAME administration. To evaluate the potential role of the renal sympathetic nerves in L-NAMEinduced hypertension, we compared the blood pressure response to L-NAME in four groups of Sprague-Dawley rats (n=8 each): (1) sham-operated vehicle-treated, (2) shamoperated L-NAME-treated, (3) denervated vehicle-treated, and (4) denervated L-NAME-treated. After renal denervation or sham surgery, L-NAME was added to the drinking N itric oxide (NO) is now known to be an important participant in a variety of physiological processes, including several that influence arterial pressure.1 Acute administration of substituted arginine analogues that inhibit NO synthesis, including /V°'-nitro-Larginine methyl ester (L-NAME), results in a prompt increase in arterial pressure.2 -3 The immediate increase in arterial pressure may be principally due to an increased vascular smooth muscle tone as a consequence of decreased endothelial synthesis of NO. Increases in sympathetic nerve activity have been described after acute NO synthesis inhibition, 46 suggesting that neurogenic mechanisms may also contribute to the acute increase in arterial pressure.Several laboratories have recently reported that continued administration of inhibitors of NO synthesis induces a sustained hypertension.79 Although a precise mechanism by which continued NO synthesis inhibition may induce chronic hypertension remains to be identified, renal control of fluid and electrolyte balance is thought to play a dominant role in the long-term control of arterial pressure in both normal and pathophysiological states.10 ' 11 Renal sympathetic nerve activity is known to be increased at least acutely after administration of NO synthesis inhibitor, 46 and activation of the renal sympathetic nerves is known to inhibit renal sodium excretion and promote renal renin secretion. 12 Thus, we hypothesized that chronic L-NAME-induced hypertension may be, in part, the result of a sustained activation of the renal sympathetic nerves and the resultant resetting of renal fluid and electrolyte balance water (70 rngVlOO mL) for 4 weeks, and arterial pressure was measured weekly by the tail-cuff method. L-NAME treatment caused a progressive increase in arterial pressure in shamoperated rats, rising to 154±6 mm Hg by week 4 of treatment compared with 115±2 mm Hg in the vehicle-treated shamoperated group (P<.005). In contrast, the development of hypertension was significantly delayed and attenuated in renaldenervated rats treated with L-NAME. The results of our study suggest that L-NAME-induced hypertension may be partly mediated by or is at least dependent on the integrity of the renal nerves. Key Words • blood pressure • end...

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In conclusion, these data suggest that titanium implants modified by the application of nanostructures promote osteogenic differentiation, and may improve the biointegration of these implants into the alveolar bone.

When sandblasted at a pressure of 0.4MPa, the zirconia specimens developed a strong bond with the tooth-colored porcelain, regardless of the type of porcelain.

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Yttria-based zirconia material (Y-TZP) widely used in dentistry, may degrade in a humid, low-temperature environment such as that in the oral cavity. The aim of this study was to compare the degradation of a new silica doped Y-TZP material with that of conventional Y-TZP by using accelerated aging tests at 200°C. The results of the accelerated tests revealed that after 50 hours of aging, the conventional Y-TZP samples had damaged surfaces that were weakened by 50 to 60%, while the silica-doped Y-TZP samples were only weakened by less than 20%. The monoclinic content of the conventional Y-TZP samples increased substantially to 62.7%, however, that of silica-doped Y-TZP samples was 18.9% after 5 hours of aging. It was concluded that a new type of silica-doped Y-TZP, created by adding a small amount of silica to Y-TZP, will be more resistant to low temperature degradation than conventional Y-TZP.

The interfacial microstructure produced through tool transit of a friction stir welded lap joint between an aluminium alloy and stainless steel was studied by transmission electron microscopy in order to clarify its early stages of formation. Transmission electron microscopy studies of the bottom surface of the exit hole revealed the presence of several mixed layers of an ultrafine intermetallic compound (IMC) and stainless steel. The joining between dissimilar materials was achieved through a continuous flow of the stirred aluminium alloy into the mixed layers and the resultant growth of the ultrafine IMCs due to the heat induced by the friction between the tool and the specimen. The continuous thin reaction layer finally produced at the interface was found to be stronger than the base aluminium alloy.