Amorphous carbon coating mixed with nano-diamonds

A low temperature plasma process for alternately depositing a diamond layer and an amorphous-carbon layer, i.e. DLC (diamond like carbon), on a same substrate was developed. In order to make both DLC and diamond coexist on a same substrate, we developed a method to form diamond at lower temperature than 500 K, since at a higher temperature DLC is easily crystallized and changed to graphite. We constructed an apparatus that had two types of plasma generators for radio frequency and microwave. The substrate temperature can be kept at 473 K during depositions for both DLC and diamond. Laser-Raman spectrometry and transmission electron microscope observation showed existence of both DLC and diamond in the coated layers. The coating has excellent mechanical properties, such as higher hardness than DLC and very low friction comparable to DLC.     

Intravenous administration of irinotecan elevates the blood beta-glucuronidase activity in rats

7-Ethyl-10-hydroxycamptothecin (SN-38) is the active metabolite of an anticancer drug, irinotecan (CPT-11). Severe late diarrhea is the dose-limiting toxic effect of CPT-11. This diarrhea has been examined regarding biliary excretion and deconjugation of SN-38 glucuronide by the enzyme beta-glucuronidase (beta-GL) in intestinal microflora. Prompted by the enzymological and structural similarity of CPT-11 to organophosphorus and carbamate insecticides, we studied the effect of CPT-11 on blood beta-GL activity in rats. The i.v. injection of CPT-11 in rats significantly elevated their plasma beta-GL activity (with phenolphthalein glucuronide as a substrate) at doses of 10 and 40 mg/kg, with peak activity observed 2-3 h after administration. SN-38 lactone and carboxylate had no effect on the plasma beta-GL level. The enhancement of the activity was also observed in serum using SN-38 glucuronide as a substrate. The serum beta-GL levels showed a close correlation between these substrates. The enhancement of plasma (serum) beta-GL activity is suggested to be a result of the release of beta-GL from liver microsomes. Serum and microsomal carboxylesterase were not significantly affected by CPT-11 administration.     

Absorption-enhancing mechanism of EDTA, caprate, and decanoylcarnitine in Caco-2 cells

The mechanism of paracellular expansion by absorption enhancers, e.g., EDTA, sodium caprate (C10), and decanoylcarnitine (DC), was studied, the focus being on the process of actin microfilament contraction in the tight junction. The effects of various inhibitors such as KN-62 (a specific inhibitor of Ca2+/calmodulin dependent protein kinase), H7 (a protein kinase C (PKC) inhibitor), and W7 (a calmodulin antagonist) were examined on the paracellular expansion by the enhancers in Caco-2 cells. From the experimental results, the following mechanisms were suggested. EDTA activates PKC by depletion of extracellular calcium via chelation resulting in expansion of the paracellular route. C10 increases the intracellular calcium level by an interaction with the cell membrane independent of cell polarity resulting in contraction with actin microfilament. DC interacts specifically with the apical membrane to increase the intracellular calcium level, but the mechanistic details subsequent to the increase of calcium are not clear.     

Retention mechanism of imidazoles in connective tissue. I. Binding to elastin

To elucidate the retention mechanism of drugs with imidazole moiety in the connective tissue, the retention form and site of [2-14C]imidazole and 2-methyl[2-14C]imidazole were studied after intravenous administration to rats (3 micromol/kg body weight). The aorta, which is representative of the connective tissue, retained considerable radioactivity after dosing for both the imidazoles. It was observed that most of the aortic radioactivity came from the irreversibly bound fraction with elastin and that this was in close agreement with the microautoradiographic observation that showed that the retention of radioactivity occurred near the elastic fiber in the aorta. Pretreatment of rats with SKF525-A significantly increased the irreversible binding of radioactivity from the imidazoles in aorta, whereas neither phenobarbital nor 3-methylcholanthrene increased the binding. Regarding the urinary metabolite profile, the excretion of intact form significantly increased by SKF525-A pretreatment for imidazole, and an increasing tendency was also observed for 2-methylimidazole. However, no in vitro irreversible binding of imidazoles to aortic tissue was observed after incubating at physiological pH and temperature. These findings indicate that the retention of drugs with imidazole moiety in the connective tissue is largely attributable to irreversible binding between the imidazole moiety and elastin, and that the binding may be mediated through cytochrome P450-independent biotransformation.     

Effects of applied stress on cavitation erosion

Cavitation erosion under static applied stress and/or alternating stress was studied using steel specimens which were set in close proximity to an oscillating horn in ion-exchanged water. For increasing static applied tensile or compressive stress, weight loss and its rate do not vary in a monotonic fashion but first decrease, then increase through a peak, and then decrease again. Tensile stress except for given stress regimes, and compressive stress at all stress levels, decreases erosion damage compared with zero-stress values. Under alternating stress, the weight loss rate varies with trends similar to those under static applied stress. However, the weight loss rate is larger than for the same static stress, so that the erosion damage is more affected by alternating stress than by static stress. The behaviors under applied stress are discussed through the effect of stress on the erosion particles.     

Reduction in polarization dependent loss of a planar lightwave circuit by ion-implantation-induced birefringence

Reduction in polarization dependent loss of a planar lightwave circuit was achieved by asymmetric birefringence formed by ion implantation, in which oxygen ions were implanted along a diagonal of a cross-section of the planar lightwave circuit. The induced birefringence has a slow axis along the line perpendicular to the diagonal. In the present research, a decrease in polarization dependent loss of up to 3.7 dB was obtained, indicating that the method is effective for reducing polarization dependent loss.     

Self‐Activated Vanadate Compounds Toward Realization of Rare‐Earth‐Free Full‐Color Phosphors

Rare‐earth‐free phosphors based on vanadate compounds were investigated, where the vanadates included chloride vanadates (M^II₂VO₄Cl), pyrovanadates (M^II₂V₂O₇), orthovanadates (M^II₃(VO₄)₂) with divalent cations M^II of Mg, Sr, Ba, and Zn, and oxofluorovanadates (A^IVOF₄) with an alkali metal A^I. A chloride pyrolysis method and a liquid phase precipitation method were proposed for preparing the chloride vanadates and pyro‐ and orthovanadates, respectively. These vanadate compounds showed self‐activated photoluminescence (PL) based on the VO₄ clusters against the ultraviolet (UV) light irradiation. The colors of PL covered almost the whole visible‐light region from blue to yellow as Sr₂VO₄Cl (deep blue), Ca₂VO₄Cl (sky blue), Ba₂V₂O₇ (green), Sr₂V₂O₇ (yellowish green), Zn₃(VO₄)₂ (yellow), and Mg₃(VO₄)₂ (yellow). A correlation was suggested from these compounds between the luminescent colors and the structural feature as the longer V–O distances in the VO₄ tetrahedra in the crystal structures led to the longer wavelength in PL. This seemed to be also applicable for the oxofluorovanadates A^IVOF₄ (A^I = K and Cs) which contain the VOF₄ polyhedra with one O^2? ion and four F^‐ ions as the ligands, as they exhibited the reddish PL.     

Can squirrel monkeys (Saimiri sciureus) learn self-control? A study using food array selection tests and reverse-reward contingency.

Eight squirrel monkeys (Saimiri sciureus) were presented with 2 stimulus arrays, namely 1 and 4 pieces of food, but they received only the array other than the one they reached for. In this reverse-reward condition, all monkeys initially showed a strong preference for the larger array. One monkey learned to reach toward the smaller array when a large-or-none reward contingency was applied (i.e., no reward followed a reach toward the larger array, but this array was given for a reach toward the smaller array). When correction trials and time-out were added to the large-or-none procedure, all remaining monkeys except 1 learned this form of self-control. Performance was maintained when correction trials were discontinued, the original reverse-reward condition was rerun, and novel array-size pairs were presented. This study demonstrates one form of self-control in a New World primate and shows the reverse-reward procedure to be a potentially valuable method for assessing species and individual differences in self-control and numerosity-related abilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Peripherally active analgesia of aminopeptidase-resistant sugar-coupled leucine enkephalin

Suramin, a promising chemotherapeutic agent, causes a dose-limiting sensorimotor polyneuropathy. We undertook a phase 1 study of suramin that included serial neurologic and electrophysiologic examinations as part of the safety evaluation. We found that 6 of 41 (15%) patients developed suramin-induced demyelinating neuropathy which resembled Guillain-Barre syndrome clinically. There was 1 asymptomatic patient with electrophysiologic abnormalities suggestive of a demyelinating neuropathy. In addition, 1 patient with mild axonal neuropathy at baseline had deterioration of his symptoms during suramin treatment. Four asymptomatic patients developed electrophysiologic findings suggestive of a mild axonal neuropathy. We conclude that: (1) serial electrophysiologic monitoring is helpful for early detection of suramin-induced neuropathy; and (2) fixed dosing schedule of suramin without adaptive control does not lead to an increased incidence of demyelinating neuropathy when compared to adaptively controlled dosing schedules.     

Fluorospectroscopic analysis of the fluorescent substances in peroxidized microsomes of rat liver

The fluorescent substances formed in rat liver microsomes in the course of lipid peroxidation were investigated by fluorescence techniques. The fluorescence emitted from peroxidizing microsomes continuously increased as lipid peroxidation progressed, while the steady-state fluorescence anisotropy increased and then reached a plateau. A similar increase was observed in the steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene in peroxidizing microsomes. The fluorescence from peroxidized microsomes consisted of at least three species having short, middle or long fluorescence lifetimes. The lifetimes and relative amplitudes of fluorescence were unaffected by the extent of lipid peroxidation. Both fluorescence of the chromolipids extracted and the proteins isolated from peroxidized microsomes had the same characteristics in fluorescence lifetimes as the fluorescence from whole peroxidized microsomes. Thus, these lipids and proteins appear to be the major biological substances responsible for the fluorescence emanating from whole peroxidized microsomes. Furthermore, fluorescent substances formed in microsomes seem to increase in quantity rather than change in quality as lipid peroxidation progresses.