Catalytic decomposition of HCFC22 (CHClF2)

The catalytic decomposition of CHClF₂ was studied over various acidic metal oxides in a fixed-bed reactor. The Cr₂O₃ZrO₂ exhibited the highest activity. The presence of water vapor in the reaction system suppresses the transformation of oxides to fluorides, progresses the formation of CO₂, and it improves the catalysts life.     

Mammalian Polycomb group genes are categorized as a new type of early response gene induced by B-cell receptor cross-linking

Polycomb group (PcG) genes were initially described in Drosophila melanogaster as regulators of the homeobox gene. Four mammalian homologues, mel-18, bmi-1, M33 and rae-28, are analyzed in this study. They not only regulate mammalian homeotic genes by analogy with their Drosophila counterparts, but also have some influence on the growth and differentiation of B lymphocytes. Here we report that these four mammalian PcG genes are rapidly induced after antigen-receptor cross-linking in B cells. Thus we would like to propose that mammalian PcG genes can be categorized as a new type of immediate early gene.     

A 99-mm2 0.7-W single-chip MPEG-2 422P@ML video, audio,and system encoder with a 64-Mb embedded DRAM for portable 422P@HLencoder system

A scalable single-chip 422P@ML MPEG-2 video, audio, and system encoder LSI for portable 422P@HL system is described. The encoder LSI is implemented using 0.13-μm embedded DRAM technology. It integrates 3-M logic gates and 64-Mb DRAM in an area of 99-mm². The power consumption is suppressed to 0.7 W by adopting a low-power DRAM core. It performs real-time 422P@ML video encoding, audio encoding, and system encoding with no external DRAM. Furthermore, the encoder LSI realizes a 422P@HL video encoder with multichip configuration, due to its scalable architecture. This results in a PC-card size 422P@HL encoder for portable HDTV codec system     

Elimination of FK-506 by continuous hemodiafiltration in a liver transplant patient

A liver transplant patient who developed renal failure postoperatively was treated using continuous hemodiafiltration (CHDF). Doses ranging from 0.01 to 0.06 mg/kg/day of FK-506 had been administered intravenously. FK-506 concentrations before and after the filter, and in the ultradiafiltrate were 45.3 +/- 2.9, 56.0 +/- 5.3, and 9.1 +/- 3.1 ng/ml (mean, +/- S.D.), respectively. The filtration rate was 23.6 +/- 6.4%, and extracted FK-506 amounted to 522.0 micrograms (11.3% of administered dose). A part of the FK-506 administered was eliminated through the filter during CHDF.     

Hemocompatible cellulose dialysis membranes modified with phospholipid polymers

Hemocompatibility is one of the most important properties for hemodialysis membranes. For improvement of the hemocompatibility on a cellulose dialysis membrane, modifications with new blood-compatible phospholipid polymers were carried out. These methods included a direct grafting of the phospholipid monomer on the membrane surface, coating the membrane surface with a water-soluble graft copolymer composed of a cellulose backbone and phospholipid polymer as a branch, and covalent bonding with a reactive phospholipid polymer on the membrane surface. These modified membranes could reduce protein adsorption as well as complement activation and platelet adhesion on the surface without any adverse effects on the membrane performance.     

Patterning characteristics under small vibrations of the mask and wafer in SR lithography

Patterning characteristics under mechanical vibrations between mask and wafer are investigated in terms of pattern profile deformation, linewidth change, and exposure dose margin by performing exposure experiments and using a Fresnel diffraction simulation. A small vibration works as a smoothing filter and provides a smooth profile in patterning. Stronger vibrations, generally, make the linewidth bigger, thereby reducing the dose margin. However, given vibrations of a particular amplitude, there is a certain range of doses in which the vibrations donot significantly affect the linewidth. Below the range, the linewidth becomes smaller; and above, it becomes larger. And it is possible to obtain the desired dimensions of delineated pattern even when the amplitude of the vibrations was a quarter of the minimum feature size.     

Influence of thermal history on primary nucleation and crystal growth rates of isotactic polystyrene

The influence of thermal history on primary nucleation and crystal growth rate of isotactic polystyrene (i-PS) was studied in a wide range of time and temperature. Samples were melted at several temperatures from 230 to 250 °C and then crystallized from those molten states and also crystallized from the glassy state. The primary nucleation rate is strongly influenced by the thermal history but the crystal growth rate is mainly governed by the crystallization temperature. Below a melt temperature of 230 °C, the nucleation density was attributed to the seed nuclei, which result from incomplete melting of the spherulites. Above 250 °C, a limited number of heterogeneous nucleation sites remain, and these sites are activated on the surface of impurities or foreign bodies in the melt. The primary nucleation is controlled heterogeneously both from the molten and the glassy states. The nucleation rate from the glassy state is faster than that from the molten state. A linear relationship between the nucleation rate and the inverse of induction time was found in each experimental condition and their slopes are related to the saturation density of the nuclei. The activation energy for the molecular transport and the primary nucleation energy were smaller than those of the crystal growth. The primary nucleation energy from the glass was lower than that from the melt. These energies are discussed in the present work.     

Lumbar intervertebral disc herniation in children less than 16 years of age. Long-term follow-up study of surgically managed cases

STUDY DESIGN: In this retrospective study, the long-term clinical results of lumbar intervertebral disc herniation in children less than 16 years of age were reviewed. OBJECTIVES: To evaluate the effectiveness of surgical treatment including posterior discectomy, extraperitoneal anterolateral discectomy, and anterior interbody fusion for lumbar intervertebral disc herniation in children less than 16 years of age. SUMMARY OF BACKGROUND DATA: Although previous follow-up studies on surgically managed lumbar intervertebral disc herniation in children and adolescents generally reveal good outcomes, few reports have focused on the time course of clinical findings and the long-term results. METHODS: The outcome of subjective symptoms, clinical signs, and time-related change of the intervertebral disc space in 11 patients were evaluated with an average follow-up period of 9 years (range, 5-12 years). RESULTS: The posterior discectomy procedure relieved clinical symptoms quickly. In the case of central herniation with or without intervertebral instability, extraperitoneal anterolateral discectomy or anterior interbody fusion led to favorable long-term results. Clinical symptoms (lower back pain, leg pain) and neurologic disturbance disappeared within 3 months after surgery. Recovery of normal straight leg raising test results (tight hamstrings), however, required much more time than recovery of other symptoms. Narrowing of the intervertebral disc space progressed up to 3-6 months after discectomy, but then disc space widening occurred. CONCLUSIONS: Satisfactory long-term clinical results and early return to school life were obtained with each surgical procedure. It is important to aim toward an early return to school via surgical treatment.     

A design technique for a high-gain, 10-GHz class-bandwidth GaAsMESFET amplifier IC module

A design procedure is proposed for a high-gain and wideband IC module, using stability analysis and a unified design methodology for ICs and packages. A multichip structure is developed using stability analysis and the requirements for stable operation are determined for each IC chip, package, and interface condition between them. Furthermore, to reduce the parasitic influences, several improvements in the interface and package design are clarified, such as wideband matching and LC resonance damping. IC design using effective feedback techniques for enlarging the bandwidth are also presented. The ICs are fabricated using 0.2-μm GaAs MESFET IC technology. To verify the validity of these techniques, an equalizer IC module for 10-Gb/s optical communication systems was fabricated, achieving a gain of 36 dB and a bandwidth of 9 GHz