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We report on the design, fabrication, and measurement of a low-temperature microwave switch architecture that can be fully integrated on chip using single Josephson junctions and superconducting bias lines. The basic switching element used is a reflective single-pole-single-throw switch that is realized by tuning the critical current of a single Josephson junction by way of a local flux bias. A single-pole-single-throw switch is demonstrated at 4.2 K to have an on/off ratio in excess of 20 dB up to 12 GHz. This element is then incorporated into the design of a single-pole-double-throw switch that exhibits an on/off ratio above 20 dB up to 10 GHz. The switches require no intrinsic power dissipation in either state, and their performance was verified for input powers of $-$100 to $-$60 dBm. S-parameter simulations using a simple lumped element model are in good agreement with the experimental data, allowing for the design to be extended to larger switch architectures.

Twenty-two female Rhesus monkeys were fed purified diets varying in calcium and fluoride content for five years and studied, using radiographic, photon absorptiometric and histologic techniques. The results suggested that 1) the addition of fluoride (50 ppm) to a diet containing 1 calcium resulted in a reduction in bone growth rate and resorption, without affecting bone size or density nor resulting in fluorosis; 2) a diet containing 0.15 calcium resulted in osteoporosis due to an increase in bone resorption; and 3) fluoride added to a similar low calcium diet prevented osteoporosis by reducing bone growth rate and resorption resulting in bones with normal density, but at the same time fluoride interfered with mineralization of osteoid leading to osteomalacia.

FT-IR studies of the secondary structure of mt-PA6 and mt-PA6 treated with L-arginine, (+)-citrulline, and L-asparagine were carried out in aqueous buffer solution. Spectral subtraction was used to remove the interfering water bands in the amide absorption region, and the amide I absorptions were monitored to investigate changes in the secondary structure of the mt-PA6 induced by the binding of these amino acids. The spectral data showed a narrowing of the amide I absorption of mt-PA6 on treatment with L-arginine, (+)-cirrulline, and L-asparagine. Deconvolution of the amide I absorption revealed vibrational bands characteristic of β-sheet (1632 cm−1), disordered or bound water (1644 cm−1), and turns (1660 cm−1) secondary structures for the mt-PA6. Curve-fitting methods were also used to examine the changes in spectra and secondary structure of the mt-PA6 resulting from amino acid treatment. Analysis of the spectral data shows that loss in intensity of the bands near 1644 and 1660 cm−1is responsible for the amino acid-induced narrowing of the mt-PA6 amide I absorption. In addition, the spectral data could suggest different binding interactions for L-arginine to mt-PA6 compared to the L-asparagine and (+)-citrulline.

Summary.Acrosin and acrosomal hyaluronidase were inhibited by tetradecyl sodium sulphate (TDSS) in vitroat concentrations of < 10−4M. TDSS prevented the removal in vitroof the cumulus oophorus by testicular hyaluronidase and the zona pellucida by acrosin. TDSS had a contraceptive effect in rabbits when administered intravaginally before coitus or released at levels of 1–3 μg/day from intrauterine silicone rubber devices.

The dopamine transporter (DAT), located presynaptically on dopamine neurons, provides a marker for certain neurological diseases. In particular, the DAT is depleted in Parkinson's disease, and the extent of depletion correlates with the loss of dopamine. Herein we describe the design, synthesis, and biological evaluation of technepine, the first ^99mTc-labeled SPECT imaging agent which targets the dopamine transporter in striatum. We have demonstrated that the DAT can accommodate a chelating unit attached to the 8-amine function of a tropane skeleton. Further, we have demonstrated for the first time that a molecule can be designed to carry the radionuclide ^99mTc across the blood−brain barrier in sufficient quantity to obtain in vivo images of the striatum in monkeys. This advance will undoubtedly lead to the design of new receptor and transporter-mediated ^99mTc agents which can label specific transporter and receptor targets in the central nervous system.

Summary.Introduction of 0·5 mg β-sitosteryl sulphate, a potent acrosin inhibitor, in K-Y jelly into the vagina of rabbits before coitus lowered the pregnancy rate. Cholesteryl sulphate had no effect. A 1·5 × 10 mm silicone rod containing 10% (w/w) β-sitosteryl sulphate released 1–2 μg of compound per day over a 16-day period in vitro. When such implants were placed in rabbit uteri, there was a significant reduction in the numbers of embryos in those horns.

Summary.Four 3 β-hydroxy-Δ5-steroid sulphates were found to be potent and specific inhibitors of the sperm acrosomal proteinase, acrosin. Two of these acrosin inhibitors, desmosteryl sulphate and cholesteryl sulphate, occur naturally in spermatozoa. Desmosteryl sulphate, an inhibitor of the in-vitro capacitation of hamster spermatozoa, has a Kiof 3·5 × 10−6mfor the inhibition of acrosin. The mechanism of inhibition of sperm capacitation by sterol sulphates is probably due to their inhibition of acrosin.

With the increased use of wood and coal for home heating, chimney sweeping is becoming a more common occupation. A preliminary study was designed to evaluate the air contaminants present in the process. Arsenic and sulfur dioxide were found along with coal tar pitch volatiles. A method of minimizing the exposure of these chemicals to chimney sweeps by spraying a water mist is discussed.

Summary SPECT scanning with TI-201 and Tc-99m offers a unique, inexpensive functional imaging modality to combine with CT stereotactic craniotomy for guiding resection of necrosis and/or tumour in patients treated with escalated doses of radiation (>6000 cGy) by either brachytherapy or radiosurgery. Thirty-two cases were analyzed, with a detailed description of the imaging and operative techniques.

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