Photoresponsive Crown Ethers. Part 11. Azobenzene-Pillared Cylindrical Macrocycle As a Photoresponsive Receptor

A cylindrical ionophore (1) in which two diaza-crown ethers are linked by two azobenzene pillars serves as a photoresponsive host molecule. In alkaline solution containing K⁺, (1) forms a cascade complex with dianionic guest molecules, but photoirradiated (1) which has a shortened cylinder cannot bind the guest molecules so effectively as (1). (1) solubilised in acidic aqueous solution by protonation of four tertiary nitrogens provides a hydrophobic cavity to bind several anionic azo dyes. The association is also suppressed by photoirradiation. The results indicate that parallel array of the azobenzene segments in (1) provides a host cavity and the photoinduced structural change is readily reflected by the association tendency. This is the first example for the photoresponsive inclusion complex.     

Development of a simple method to evaluate medical staff radiation dose and its application to a software system supporting PET facility operation

In recent years, positron-emitting labelled radiopharmaceuticals have come to be used in conjunction with positron emission tomography (PET) in various clinical diagnoses. Radiation exposure of the medical staff is a key issue in the design of PET facilities intended to handle large numbers of persons for PET diagnosis. As a first step, the radiation dose to individuals who received radiopharmaceuticals was calculated using a mathematical phantom model and the EGS4 electromagnetic cascade Monte Carlo code and MCNP Monte Carlo code. Dose rate behind a lead shield was also calculated for various lead thicknesses. The radiation dose distribution around a syringe containing a positron emitter was calculated. The calculated dose distributions were fitted to polynomial equations. These calculations were evaluated against measurements. The second step was to evaluate medical staff dose at a specified time by superimposing dose distribution from each person who received radioisotopes taking into account radioactive decay. In this way, we developed software to support PET facility operation, namely, planning, prediction, control of medical staff dose and facility operation. This system was also designed to schedule daily radiopharmaceuticals production and to manage radioactive wastes by taking decay time into account.     

Casting of organic glass by radiation-induced polymerization of glass-forming monomers at low temperature. II. Optical strain of remaining stress type

Previously it was found that casting could be carried out efficiently without strain formation by radiation-induced polymerization of glass-forming monomers. Two types of strain were observed in casting: thermal stream type, which was studied previously, and remained stress type. In this report, the effect of various factors on the formation of remaining stress-type strain in radiation-induced casting polymerization was studied. It was found that the molecular weight of prepolymer did not affect strain formation, while prepolymer concentration and viscosity of the system had a serious influence on strain formation. It could be deduced that this type of strain formed as a result of remaining inner stress due to poor relaxation of the shrinking stress. It was realized that less volume shrinkage of glass-forming monomers accompanying casting polymerization reduced the strain formation of this type in radiation-induced casting polymerization at low temperatures.     

Threshold voltage of ion implanted GaAs MESFET

Threshold voltages for ion implanted GaAs MESFETs are measured and shown to have good coincidence with calculated results. The effect of implantation energy on threshold voltage is discussed. The optimum implantation energy is about 45 ~ 60 keV.     

Inhibitory effect of Perilla frutescens and its phenolic constituents on cultured murine mesangial cell proliferation

BACKGROUND: Short-stay obstetric stays have been the recent focus of many social and medical debates. We did a retrospective study of a large community teaching hospital's experience in making a safe transition to short-stay obstetrics. METHODS: Over a 10-month period, a multidisciplinary committee developed an intrapartum and postpartum education program to allow short hospital stays after uncomplicated vaginal deliveries. Computerized data were then retrieved on all uncomplicated spontaneous vaginal deliveries (DRG 373) from January 1994 to March 1995. RESULTS: During the study period, 554 women were discharged on the first postpartum day, resulting in three maternal readmissions and nine pediatric readmissions (combined readmission rate of 2.2%). This low readmission rate compared favorably with our experience with 2,563 uncomplicated vaginal deliveries from January 1991 to December 1993, immediately before the institution of the short-stay obstetrics program (combined readmission rate of 3.9%). The average hospital cost for a 1-day stay was $1,714 compared with $2,477 for a 2- to 3-day stay, representing a saving of only 31%. CONCLUSIONS: Early obstetric discharges after an uncomplicated spontaneous vaginal delivery can be safe and effective with appropriate patient selection and support.     

Predictive factors for in-hospital mortality and delayed mortality following aneurysmal subarachnoid hemorrhage

It is important to detect predictive factors for in-hospital and delayed mortality of patients with subarachnoid hemorrhage (SAH) due to ruptured aneurysm. Forty-eight patients with initial bleeding of aneurysmal SAH were referred to our hospital from January 1982 to December 1985. In-hospital mortality was 16.7% (8 to 48), and 15% (6) of forty patients died later during the follow-up period. Using the Kaplan-Meier method we were able to conclude that, cumulatively, there was 70.8% probability that much patients would survive for 10 years. We analysed predictive factors of in-hospital and delayed mortality retrospectively. The most significant predictive factor for in-hospital mortality was SAH grading on admission, and for delayed mortality (29.2%) age on admission was the best predictive factor. In fact, two patients died with cardiac event during the follow-up period. This result suggests that, although the SAH grading on admission was the second most significant factor for delayed mortality, patients who survived in the acute phase had a survival probability similar to those in a normal control group.