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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.

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.

One hundred patients with spinal cord injury had various parameters of bone mineral estimated. The results were compared to a group of matched normals. A Packard Osteodensitometer with a 125I point source was used to measure bone mineral mass in the distal radius. The cortical bone was found to be normal in the spinal cord injury patients as shown by photon densitometry, and radiographic measurement of the metacarpal and clavicular indices. It was not related to the date or the level of the spinal injury and was related to age in a similar fashion to the normals. However, hand radiographs demonstrated marked loss of trabecular bone in 52 patients (including 14 paraplegics). This suggests that, in spinal cord Injury, cortical bone is preserved while trabecular bone is lost, and because this is dissimilar from idiopathic osteoporosis a possible neuronal etiology is postulated.

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.