Electrical Conduction in Magnesium Phosphate Glasses Containing Heavy Water

The relation between deconductivity and the concentration of protons or deuterons was investigated in 45MgO · 55P₂O₅ (in mol%) glasses containing small amounts of "water." The conductivity was shown to increase in proportion to the square of the proton concentration as reported in calcium phosphate glasses. The same relation was found to be valid for the deuterated specimens, although their conductivity was somewhat lower than that in the protonated glasses when compared at the same concentration of OD or OH groups. These results strongly suggest that protons are the charge carriers in these glasses. The conductivities were measured also for specimens containing both protons and deuterons in different ratios. No distinct deviation was observed from additivity within the concentration range examined.     

Antineutrophil cytoplasmic autoantibodies in 6 patients with renal failure and systemic sclerosis

OBJECTIVE: To elucidate the distribution and frequency of antineutrophil cytoplasmic autoantibodies (ANCA) in systemic sclerosis. METHODS: Patient sera were analyzed by indirect immunofluorescence and by enzyme linked immunosorbent assay. RESULTS: High titers for perinuclear ANCA correlated with rapid deterioration of renal function. Patients were normotensive with normal plasma renin levels, but anemia, pulmonary hemorrhage and thrombocytopenia were problematic. All patients had anti-myeloperoxidase antibodies and some had anti-nRNP, anti-DNA, anti-Sm and LE cell antibodies. Outcome was poor except for one patient treated by plasmapheresis and cyclophosphamide. CONCLUSION: A renal specific subset of systemic sclerosis is suggested.     

Defects of immune cells in the senescence-accelerated mouse: a model for learning and memory deficits in the aged

AM1 and PM3 complete geometry optimizations were performed on 19 arotinoids congeneric with (E)-4-[2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2- naphthalenyl)-1-propenyl] benzoic acid (TTNPB), a very potent agent in carcinoprevention and carcinotherapy. Sixteen TTNPB conformations with close energy were obtained and characterized; four representative conformations were then studied for 14 derivative compounds, for which we found a substantial non-planarity of the two aromatic moieties. Large rotational flexibility of the arotinoid ring fragments was predicted by both methods. Very low barriers (0.4-3.9 kcal/mol) were found for the tetralenyl ring rotation. The two methods also agreed in predicting benzoic acid moiety rotation in a wide range of torsion angle values except those close to 0 or 180 degrees for which the PM3 rotational barriers were found to be considerably lower than the AM1 ones. This high conformational flexibility of arotinoid molecules may facilitate their favorable orientation in the process of fitting to the receptor sites.     

Nuclear oncology with monoclonal antibodies and peptides

Imaging and therapy using radiolabeled monoclonal antibodies have proved useful in many clinical studies. However, immunogenicity of mouse antibodies to human and insufficient tumor-to-normal tissue ratios remained to be solved. Chimerization and humanization by genetic engineering, and multistep targeting techniques have enabled lower immunogenicity and higher tumor-to-normal tissue contrast. Peptides like somatostatin-analogs have been reportedly useful in imaging tumors, which are either somatostatin receptor positive or negative. Elevated normal tissue accumulation of radiolabeled peptides is a drawback in aiming internal radiation therapy.     

Effects of strong pulsed magnetic fields on the cardiac activity ofan open chest dog

The heart of an open chest dog was stimulated by strong magnetic fields which were damped sinusoidal pulses with the one-cycle period of 1.47 ms. Stimulation effects were detected by electrocardiograph (ECG) and arterial blood pressure as a function of the strength of the field, the triggering point in the cardiac cycle, and the position of a stimulating coil. The threshold for arrhythmias was a minimum for the stimuli triggered at the apex of the T wave and on the P wave in the ECG. Premature ventricular and premature atrial contractions occurred according to whether the coil was placed over the ventricles or the atria. Ventricular defibrillation can not be attained by the magnetic stimulus with the flux density of 9.2 T which was the maximum field used     

Site-specific cleavage of tRNA by imidazole and/or primary amine groups bound at the 5''-end of oligodeoxyribonucleotides

Thrombin, a serine protease, is a potent mitogen for vascular smooth muscle cells (SMCs), but its mechanism of action is not known. Since L-ornithine is metabolized to growth-stimulatory polyamines, we examined whether thrombin regulates the transcellular transport and metabolism of L-ornithine by vascular SMCs. Treatment of SMCs with thrombin initially (0 to 2 hours) decreased L-ornithine uptake, whereas longer exposures (6 to 24 hours) progressively increased transport. Kinetic studies indicated that thrombin-induced inhibition was associated with a decrease in affinity for L-ornithine, whereas stimulation was mediated by an increase in transport capacity. Thrombin induced the expression of both cationic amino acid transporter (CAT)-1 and CAT-2 mRNA. Furthermore, thrombin stimulated L-ornithine metabolism by inducing ornithine decarboxylase (ODC) mRNA expression and activity. The stimulatory effect of thrombin on both L-ornithine transport and ODC activity was reversed by hirudin, a thrombin inhibitor, and was mimicked by a 14-amino acid thrombin receptor-activating peptide. Thrombin also markedly increased the capacity of SMCs to generate putrescine, a polyamine, from extracellular L-ornithine. The thrombin-mediated increase in putrescine production was reversed by N(G)-methyl-L-arginine, a competitive inhibitor of cationic amino acid transport, or by alpha-difluoromethylornithine (DFMO), an ODC inhibitor. DFMO also inhibited thrombin-induced SMC proliferation. These results demonstrate that thrombin stimulates polyamine synthesis by inducing CAT and ODC gene expression and that thrombin-stimulated SMC proliferation is dependent on polyamine formation. The ability of thrombin to upregulate L-ornithine transport and direct its metabolism to growth-stimulatory polyamines may contribute to postangioplasty restenosis and atherosclerotic lesion formation.     

Synthesis, structure and photoelectrochemical performance of micro/nano-textured ZnO/eosin Y electrodes

Micro/nano-textured ZnO thick films were synthesized through deposition and pyrolysis of layered hydroxide zinc acetate (LHZA), Zn₅(OH)₈(CH₃COO)₂·2H₂O. LHZA films having a unique, rose-like morphology were initially deposited on conducting glass sheets in a chemical bath composed of methanol and zinc acetate dihydrate at 60 °C under neutral conditions. Pyrolysis of the LHZA films resulted in formation of ZnO without destroying the original morphology. Pyrolysis temperatures were found to greatly influence grain sizes and specific surface areas of the ZnO films. Photoelectrochemical performance of the films as ZnO/eosin Y electrodes was investigated in dye-sensitized solar cells using an I⁻/I₃⁻ redox electrolyte solution. The cell using the ZnO film pyrolyzed at 150 °C exhibited overall light to electricity conversion efficiencies of 2.0 and 3.3% under an AM-1.5 illumination at 100 and 10 mW cm⁻², respectively. While microscale pores in the electrodes facilitated mass transfer of fluid electrolytes in the depth direction, nanoscale pores contributed to an increase in the amount of adsorbed dye. The maximum incident photon-to-current conversion efficiency (IPCE) of the electrode reached 84.9% at a wavelength of 530 nm.     

Solid-state source of atomic oxygen for low-temperature oxidation processes: application to pulsed laser deposition of TiO2:N films

An atomic oxygen (AO) source has been redesigned to coordinate with a pulsed laser deposition system and used to grow nitrogen-doped TiO(2) films by deposition of TiN and simultaneous irradiation of the substrate with AO. The AO source uses an incandescently heated thin tube of zirconia as an oxygen permeation media to generate pure AO of low kinetic energy. The emission flux is calibrated using a silver-coated quartz crystal microbalance. The thin shape of the probe and transverse emission geometry of this emission device allow the emission area to be positioned close to the substrate surface, enhancing the irradiation flux at the substrate. AO irradiation is crucial for formation of TiO(2) phases via oxidation of the deposited TiN laser plume, and is effective for decrease of the substrate temperature for crystallization of anatase phase to as low as around 200 °C.