Effects of post annealing on removal of defect states in silicon oxynitride films grown by oxidation of silicon substrates nitrided in inductively coupled nitrogen plasma

Ultra thin (5 nm) silicon oxynitride (SiON) films were fabricated at a low temperature using nitrogen plasma generated by an inductively coupled plasma system. Effects of post-metalization annealing (PMA) of Al/SiON/Si MOS structure on the electrical properties of the SiON films were studied and correlations between the charge trapping states and the leakage current were established. Positive charge trapping by interface states generated by plasma damage was characterized by the hysteresis in high-frequency capacitance-voltage (C-V) characteristics. Hysteresis was observed to be completely removed by PMA while interface state density at the Si mid band gap reduced from 2.2×10¹³ to 3.7×10¹¹/eV/cm² and the oxide fixed charge density changed from 3.3×10¹² to −4×10¹¹/cm². The leakage current also decreased significantly, by more than two orders of magnitude, with PMA. The analysis of the leakage current using trap assisted tunneling (TAT) mechanism indicated that with PMA, the trap energy level in the SiON film becomes shallower from 1.3 to 0.7 eV. The positive trapped charges were observed to be annihilated by PMA and the trapping sites became neutral trap centers in the SiON film. This could lead to the reduction in the leakage current component given rise to by TAT.     

High performance liquid chromatographic separation of diacylglycerol acetates to quantitate disaturated species of lung phosphatidylcholine

A high-performance liquid chromatographic (HPLC) separation of diacylglycerol acetates to quantitatite disaturated species of lung phosphatidylcholine (PC) was studied. The diacylglycerol acetates were applied on a reversed phase column, eluted by an isocratic solvent, acetonitrile/isopropanol/water (35:15:1, v/v/v) at a flow rate of 1 ml/min, and detected by differential refractometry (RI). This isocratic HPLC method was useful to separate disaturated species from the others of lung PC. The quantitative analysis of the molecular species separated by HPLC was studied by RI detection. Chroamtograms obtained by RI detection and radioactivity determination of diacylglycerol [³H]acetates prepared by [³H]acetic anhydride were almost identical. The RI detector responsed in the same degree for different, authentic standards of diacylglycerol acetates. The detection limit with RI detection was about 30 nmoles. Molecular species of PCs from human lung and carcinoma tissues were analyzed by this HPLC method. The contents of disaturated species were very similar to those reported previously. These results indicate that RI detection is very useful in the nmole range for the quantitative analysis among the molecular species containing disaturated species.     

Transmittance and cathodoluminescence of AlN ceramics sintered with Ca3Al2O6 as sintering additive

Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca₃Al₂O₆ (C₃A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C₃A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C₃A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density.     

Ulcerative colitis with skip lesions at the mouth of the appendix: a clinical study

OBJECTIVE: We examined the clinical characteristics of ulcerative colitis patients who demonstrated endoscopically discontinuous lesions at the mouth of the appendix. METHODS: Of patients with initial or recurrent active ulcerative colitis who underwent total colonoscopy during the past 3 yr at Osaka City General Hospital, we selected those who had skip lesions in the mouth of the appendix before treatment, and examined their gender, age, disease type, sites of lesions, inflammatory reaction, severity of disease, effects of treatment, and posttreatment course. RESULTS: Discontinuous lesions at the mouth of the appendix were found in 10 patients, who had the following common clinical features: the major lesion was usually present in the lower part of the large bowel including the rectum, many of the patients had suffered an initial attack only, all patients had mild disease, and many of the patients responded quite satisfactorily to treatment with salicylazosulfapyridine. CONCLUSION: Numerous patients with ulcerative colitis with discontinuous lesions at the mouth of the appendix were observed and their clinical characteristics were examined. Determination of the clinical significance of skip lesions in the appendix will contribute to elucidation of the pathogenesis of ulcerative colitis.     

Experimental infection of Naegleria fowleri in mice

PURPOSE: To determine possible cognitive and behavioral effects of antiepileptic drug (AED) therapy by assessing children with newly diagnosed epilepsy before and after initiation of treatment. A comparison group of children with diabetes mellitus (DM) was included to control for the effects of practice, maturation, and chronic illness. METHODS: Baseline neuropsychological assessments were completed for children with epilepsy (n = 37) and children with DM (n = 26) recruited through outpatient clinics at a regional children's hospital. Children were reevaluated 6 months from baseline testing. At follow-up, children with epilepsy had therapeutic AED levels and controlled seizures. Statistical analysis included a between-group repeated measures ANCOVA with pretest scores serving as the covariate. RESULTS: Significant differences between groups were not found for any cognitive or behavioral factors, including attention (p < 0.24), immediate memory (p < 0.24), delayed memory (p < 0.10), complex motor speed (p < 0.19), or behavior problems (p < 0.89). CONCLUSIONS: Changes in performance on cognitive and behavioral measures were not different for children treated with AEDs and controls. Although adverse effects may be associated with prolonged treatment, results would not suggest adverse effects from AED monotherapy during the first 6 months of therapy.     

Net shape formation of sub-micron alumina with reduced flaws by high-speed centrifugal compaction process

A new compacting method for powder materials is presented. High-Speed Centrifugal Compaction Process (HCP) utilizes centrifugal force of about 10,000 g for the compaction. HCP is suitable for net shape compaction of fine sub-micron and nano-powders. HCP possesses a unique compacting mechanism that is different from other colloidal processes including Pressure Casting (PC), and has a number of useful characteristics. HCP has a higher compacting speed than PC, wide applicability for net shape formation, as well as a defect removing function. Because of homogeneous and flawless green microstructure, HCP alumina shows superior sinterability and higher strength and hardness than most of other aluminas. This article is based on a presentation made in the symposium “The 3rd KIM-JIM Joint Symposium on Advanced Powder Materials“, held at Korea University, Seoul, Korea, October 26–27, 2001 under auspices of The Korean Institute of Metals and Materials and The Japan Institute of Metals.     

Effect of bile acid feeding on hepatic steroid 12 α-hydroxylase activity in hamsters

The effects of feeding cholic acid, chenodeoxycholic acid and ursodeoxycholic acid on the activity of the hepatic steroid 12α-hydroxylase, gallbladder bile acid composition, fecal neutral sterol output, cholesterol synthesis and bile acid synthesis were determined in female hamsters. The 12α-hydroxylase activity was inhibited to 56% by cholic acid, to 62% by chenodeoxycholic acid, and to 78% by ursodeoxycholic acid compared with the control. Bile acid composition was altered by feeding of cholic acid and chenodeoxycholic acid to be rich in the given bile acids. Fecal neutral sterol output increased about twice by feeding chenodeoxycholic acid and ursodeoxycholic acid, whereas cholic acid had no significant effect. Body cholesterol synthesis increased to 217% by chenodeoxycholic acid and to 274% by ursodeoxycholic acid, whereas effect of cholic acid was not significant. Bile acid synthesis was suppressed to 48% of control only by chenodeoxycholic acid. A positive correlation between the 12α-hydroxylase activity and the bile acid synthesis was observed in the control, chenodeoxycholatefed and ursodeoxycholate-fed animals. In conclusion, ursodeoxycholic acid might have less inhibitory effect on the steroid 12α-hydroxylase and the bile acid synthesis than chenodeoxycholic acid.