High current variable temperature electrical characterization system for superconducting wires and tapes with continuous sample rotation in a split coil magnet

A new state-of-the-art electrical transport measurement system was developed for the characterization of industrially produced coated conductors (CCs). The current leads are rated to a conduct current of up to 1000 A, which opens up the possibility of measuring the critical current I_c of tapes at a wide range of temperatures. The setup operates in a He-gas flow cryostat that provides stable temperatures between 1.8 and 200 K. The setup is equipped with a split-coil magnet that can apply fields of up to 6 T. A continuous rotation of the sample with respect to the magnetic field with an angular resolution of 0.5° enables characterization of anisotropic I_c of different tapes. In the measured voltage-current curves, weak sample heating mostly occurs from the dissipation in the tape during the I_c transition. It is demonstrated that the system can provide reliable data on the properties of CCs at temperatures lower than 77 K for a magnet design and other applications. The results allow the study of vortex pinning for further prospects of engineering the microstructure of the superconducting layer as well as to assess the performance of various tapes with different architectures to achieve optimum performance at different operating temperatures and magnetic fields.

[Urinary bladder tuberculosis and bacillus calmette-guérin instillation: reduced efficacy of bisoprolol in hypertension]

HISTORY AND ADMISSION FINDINGS

A 71-year-old patient with a superficial carcinoma of the urinary bladder and high risk of recurrence was treated with intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection. As a complication of the catheterization during BCG-instillation therapy the patient suffered from tuberculosis. The patient received a tuberculosis triple-therapy including rifampicin 600 mg once daily, isoniazid 300 mg once daily and ethambutol 400 mg thrice daily. The existing arterial hypertension had successfully been controlled by 3.75 mg bisoprolol medication once daily for the last 15  years. An increase of blood pressure and cardiac arrhythmia were seen after combining the β (1)-receptor blocker treatment with the triple-therapy.

INVESTIGATIONS AND DIAGNOSIS

The blood pressure was 160 / 90 mmHg. The heart rate reflected a value of 98  beats per minute. In the resting ECG monotopic ventricular extrasystoles could be diagnosed.

TREATMENT AND COURSE

The dosage of bisoprolol was changed to 3.75 mg in the morning and additional 1.875 mg in the evening. Due to this increase of dosage the blood pressure could be controlled sufficiently.

CONCLUSION

Rifampicin is one of the best known potent enzyme inducing drugs. It strongly induces the expression of cytochrome P450 3A4 in the liver. The enzyme induction enhance the hepatic bisoprolol metabolism, hence the metabolic clearance of the drug increased. The maximal plasma level of bisoprolol decrease and in our use the arterial hypertension could not be treated sufficiently. It is well known that half the dose of bisoprolol undergoes oxidative metabolism in the liver and the rest eliminated unchanged in the kidney. A dosage adjustment of bisoprolol is necessary if the clinical status of the patient requires treatment with the antituberculosis drug rifampicin.

[Urinary bladder tuberculosis and Bacillus Calmette-Guérin instillation: reduced efficacy of bisoprolol in hypertension]

HISTORY AND ADMISSION FINDINGS

A 71-year-old patient with a superficial carcinoma of the urinary bladder and high risk of recurrence was treated with intravesical instillation of Bacillus Calmette-Guérin (BCG) after transurethral resection. As a complication of the catheterization during BCG-instillation therapy the patient suffered from tuberculosis. The patient received a tuberculosis triple-therapy including rifampicin 600 mg once daily, isoniazid 300 mg once daily and ethambutol 400 mg thrice daily. The existing arterial hypertension had successfully been controlled by 3.75 mg bisoprolol medication once daily for the last 15 years. An increase of blood pressure and cardiac arrhythmia were seen after combining the β1-receptor blocker treatment with the triple-therapy.

INVESTIGATIONS AND DIAGNOSIS

The blood pressure was 160/90 mm Hg. The heart rate reflected a value of 98 beats per minute. In the resting ECG monotopic ventricular extrasystoles could be diagnosed.

TREATMENT AND COURSE

The dosage of bisoprolol was changed to 3.75 mg in the morning and additional 1.875 mg in the evening. Due to this increase of dosage the blood pressure could be controlled sufficiently.

CONCLUSION

Rifampicin is one of the best known potent enzyme inducing drugs. It strongly induces the expression of cytochrome P450 3A4 in the liver. The enzyme induction enhance the hepatic bisoprolol metabolism, hence the metabolic clearance of the drug increased. The maximal plasma level of bisoprolol decrease and in our use the arterial hypertension could not be treated sufficiently. It is well known that half the dose of bisoprolol undergoes oxidative metabolism in the liver and the rest eliminated unchanged in the kidney. A dosage adjustment of bisoprolol is necessary if the clinical status of the patient requires treatment with the antituberculosis drug rifampicin.

Electrokinetic investigation of surfactant adsorption

Fuerstenau [D.W. Fuerstenau, in: M.L. Hair (Ed.), Dekker, New York, 1971, p. 143] has already discussed the role of hydrocarbon chain of surfactants, the effect of alkyl chain length, chain structure and the pH of the solution on the adsorption process of surfactants. Later Kosmulski [M. Kosmulski, Chemical Properties of Material Surfaces, Surfactant Science Series, vol. 102, Dekker, New York, Basel, 2001] included the effect of surfactant concentration, equilibration time, temperature and electrolyte in his approaches. Certainly, the character of the head groups of the surfactant and the properties of the adsorbent surface are the basis for the adsorption process. Different surfactants and adsorbents cause different adsorption mechanisms described firstly by Rosen [M.J. Rosen, Surfactants and Interfacial Phenomena, second ed., Wiley, New York, 1989]. These adsorption mechanisms and their influencing factors were studied by electrokinetic investigations. Here only changes of the charges at the surfaces could be detected. To control the results of electrokinetic investigations they were compared with results from ellipsometric measurements. In the case of surfactant adsorption the chain length was vitally important. It could be shown by the adsorption of alkyl trimethyl ammonium bromides onto polymer films spin coated at wafer surfaces. The influence of the chain length depending on surface properties of the polymer film was studied. Streaming potential measurements were applied for these investigations. The obtained results enabled us to calculate the molar cohesive free energy per mol of CH2-group in the alkaline chain of the surfactant if all other specific adsorption effects were neglected.

Probing highly confined optical fields in the focal region of a high NA parabolic mirror with subwavelength spatial resolution

Parabolic mirrors with a high numerical aperture can be conveniently used to produce highly confined optical fields in the focal region. Furthermore, these fields can have interesting polarization behaviour due to the high numerical aperture. In particular, if the mirror is illuminated with a size matched radially polarized or azimuthally polarized doughnut mode, the electric field has in the focal region almost exclusively a longitudinal or a transverse polarization component. Such field distributions are interesting for applications in confocal or near-field optical microscopy. Here we present experimental results where we have probed some of these field distributions by raster scanning a fine gold tip in nanometer steps through the focal region and detecting the scattered light intensity. The measured intensity patterns are compared with corresponding vector-field calculations.

Confocal microscopy with a high numerical aperture parabolic mirror

A novel high-resolution stage scanning confocal microscope for fluorescence microscopy and spatially resolved spectroscopy with a high numerical aperture (NA 1) parabolic mirror objective is investigated. A spatial resolution close to the diffraction limit is achieved. As microscopic fluorescent test objects, dye-loaded zeolite microcrystals (diameter approx. 0.4 microm) and single fluorescent molecules were used. Confocal fluorescence images show a spatial resolution of .x = 0.8 . both at room temperature and at 1.8 K. Imaging of a quasi-point light source and focusing by the parabolic mirror were investigated experimentally and theoretically. Deviations between the theoretical results for a perfect parabolic mirror and the experimental results can be attributed to small deviations of the mirror profile from an ideal parabola.