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Notes: This paper reports an automatic instrument developed for characterization of optical waveguides. A specially designed waveguide excitation unit offers a flexible platform for measurement of optical waveguide characteristics like number of propagating modes, mode field intensity distribution, the refractive index profiles, waveguide geometry, attenuation, and dispersion. Further, the availability of attachments like filters, polarizers, chopper, intensity profiler, and CCD camera make the instrument flexible enough for a variety of other experiments also. The instrument is PC controlled and assisted by user friendly menu-driven software. A large number of waveguides have been analyzed using the setup. These results are also presented in the paper. © 1995 American Institute of Physics.

Notes: The corrosion behaviour of an indigenous cast alloy of Ag-Sn-Cu, developed for crown and bridge prostheses, was studied in artificial saliva, with and without the addition of 0·1 m lactic acid, using a potentiostatic technique, and compared with that of the standard cast alloy of Ag-Pd (Ney 76). The values of different parameters such as corrosion potential and corrosion current density were determined for the indigenous alloy of Ag-Sn-Cu and the Ag-Pd alloy. The rate of corrosion of the indigenous alloy was found to be relatively higher than that of the Ag-Pd alloy up to an applied potential of + 400 mV. However, while the indigenous alloy showed a distinct tendency for passivation below + 200 mV at the current level of 0·5 mA/cm2 in the artificial saliva (pH 5·7) at 37 °C, no such tendency for passivation was shown by the Ag-Pd alloy even up to + 400 mV. The tendency for passivation by the indigenous Ag-Sn-Cu alloy, however, was not shown in the artificial saliva in the presence of 0·1 m lactic acid (pH. 2·7) at 37 °C. Minor variation was observed in the corrosion behaviour of the indigenous Ag-Sn-Cu alloys of different grades prepared by alloying elements of varying purity.

Notes: A. virus causing mosaic and leaf deformation of Physalis minima has been identified as an isolate of cucumber mosaic virus (CMV) on the basis of its transmission by aphids in a non-persistent manner, polyhedral particles of 29 nm diameter, molecular weight of coat protein subunits us 24-5 kDa. serological relationship with a CMV isolate and a tripartite single-stranded RNA genome with a subgenomic RNA4- Furthermore. cDNA representing coat protein gene was synthesized and cloned. Complete nucleotide sequences (890 nt) were obtained which showed a coat protein gene open reading frame of 657 residues. THE nucleotide sequences provided the 218 amino ACID sequences of the coat protein. Nucleotide as well as amino acid sequences revealed more than 90% identity with the CMV subgroup I strains.

Notes: 1. Plasma levels of propranolol were measured fluorometrically in patients with angina pectoris and in patients admitted to the Coronary Care Unit with acute myocardial infarction.2. In thirty patients with stable angina pectoris, plasma propranolol levels varied almost linearly with doses between 10 and 120 mg during 6-hourly chronic oral administration. Plasma levels greater than 100 ng/ml produced 70–80% reduction in the tachycardia induced by strenous exercise on a treadmill.3. In nineteen patients with acute myocardial infarction given oral propranolol, 20 mg 6-hourly, peak as well as trough plasma levels of the drug increased progressively but remained below 100 ng/ml in all except two patients during the first 24 h after their admission to the Coronary Care Unit.4. The data suggest that the use of low and fixed doses of propranolol may not produce adequate plasma levels or significant β-adrenoceptor blockade in the early stages of acute myocardial infarction in man.

Notes: 1. The effects on the coronary and systemic haemodynamics of intravenous and intracoronary injections of two benzfuran derivatives, amiodarone and its brominated analogue (L8040), were studied in open-chest anaesthetized dogs. The effects of L8040 on cardiac intracellular potentials after 6 weeks of 20 mg/kg intraperitoneal injections in rabbits were also investigated.2. Both compounds produced dose-related and quantitatively similar decreases in coronary vascular resistance following their intracoronary administration; threshold effects occurred with about 0.25 mg of each drug and maximal effects with 4 mg. Larger intracoronary doses produced measurable systemic effects.3. Intravenous injections of amiodarone and L8040 (2·5·10 mg/kg) produced dose-related decreases in heart rate and aortic pressure with a fall in total peripheral resistance. The left ventricular output was either unaffected or increased with a consistent augmentation in stroke volume.4. The bradycardia produced by both drugs was associated with prolongation of the P–R interval of the electrocardiogram with no significant effect on the QRS duration or the Q–T interval.5. Each drug produced a decrease in the total peripheral vascular resistance with no change in left ventricular end diastolic pressure except after 10 mg/kg doses which led to an increase in this parameter.6. Cardiac contractile force and peak LV dp/dt were reduced by both drugs in a dose-related manner.7. Chronic intraperitoneal administration of L8040 in rabbits caused a prolongation of the duration of the atrial and ventricular intracellular potential without an effect on the maximal rate of depolarization.8. The effects of amiodarone or L8040 on the coronary circulation and arterial pressure may be attributed to their vasodilator properties but their depressant actions on cardiac contractile force and peak LV dp/dt with an increase in left ventricular end diastolic pressure at high doses, also suggest intrinsic negative inotropic propensity for both compounds.9. It is concluded that the overall effects on coronary and systemic haemodynamics of amiodarone and its brominated analogue are likely to permit a favourable influence on the balance of oxygen supply and demand in myocardial ischaemia; in addition, their actions on sinoatrial and atrio-ventricular conduction as well as those on cardiac repolarization suggest potential antiarrhythmic properties which merit investigation.