Roles of excess minority carrier recombination and chemisorbed O2 species at SiO2/Si interfaces in Si dry oxidation: Comparison between p-Si(001) and n-Si(001) surfaces.

This study provides experimental evidence for the following: (1) Excess minority carrier recombination at SiO2/Si interfaces is associated with O2 dissociative adsorption; (2) the x-ray induced enhancement of SiO2 growth is not caused by the band flattening resulting from the surface photovoltaic effect but by the electron-hole pair creation resulting from core level photoexcitation for the spillover of bulk Si electronic states toward the SiO2 layer; and (3) a metastable chemisorbed O2 species plays a decisive role in combining two types of the single- and double-step oxidation reaction loops. Based on experimental results, the unified Si oxidation reaction model mediated by point defect generation [S. Ogawa et al., Jpn. J. Appl. Phys., Part 1 59, SM0801 (2020)] is extended from the viewpoints of (a) the excess minority carrier recombination at the oxidation-induced vacancy site and (b) the trapping-mediated adsorption through the chemisorbed O2 species at the SiO2/Si interface.

Decrease in serum anti-Müllerian hormone level per puncture with laparoscopic ovarian drilling using ultrasonically activated device.

PURPOSE: To determine the contributing factor in infertility treatment with laparoscopic ovarian drilling (LOD) to the decrease in serum anti-Müllerian hormone (AMH) levels in patients with polycystic ovarian syndrome using an ultrasonically activated device. METHODS: A retrospective analysis was performed in 60 patients (aged 23-36 years) who received 25-120 punctures in each ovary with LOD treatment from January 2014 to December 2018. RESULTS: The mean decrease in serum AMH level per puncture with LOD was 0.07 ± 0.04 ng/ml in all 60 patients and 0.08 ± 0.04 ng/ml in patients with ≥10 ng/ml preoperative serum AMH level, which was significantly higher than in those with <10 ng/ml (0.05 ± 0.02 ng/ml). The mean decrease in serum AMH level per puncture in patients with body mass index (BMI) < 18.5 kg/m2 (0.10 ± 0.03 ng/ml) was significantly higher than in those with BMI 18.5-25 kg/m2 (0.07 ± 0.04 ng/ml) and >25 kg/m2 (0.06 ± 0.02 ng/ml). CONCLUSIONS: The mean decrease in serum AMH levels per puncture with LOD using an ultrasonically activated device depends on the preoperative serum AMH level and BMI of patients.

Development of an amorphous selenium-based photodetector driven by a diamond cold cathode.

Amorphous-selenium (a-Se) based photodetectors are promising candidates for imaging devices, due to their high spatial resolution and response speed, as well as extremely high sensitivity enhanced by an internal carrier multiplication. In addition, a-Se is reported to show sensitivity against wide variety of wavelengths, including visible, UV and X-ray, where a-Se based flat-panel X-ray detector was proposed. In order to develop an ultra high-sensitivity photodetector with a wide detectable wavelength range, a photodetector was fabricated using a-Se photoconductor and a nitrogen-doped diamond cold cathode. In the study, a prototype photodetector has been developed, and its response to visible and ultraviolet light are characterized.

Gas Barrier Properties of Chemical Vapor-Deposited Graphene to Oxygen Imparted with Sub-electronvolt Kinetic Energy.

Graphene gas-barrier performance holds great interest from both scientific and technological perspectives. Using in situ synchrotron X-ray photoelectron spectroscopy, we demonstrate that chemical vapor-deposited monolayer graphene loses its gas-barrier performance almost completely when oxygen molecules are imparted with sub-electronvolt kinetic energy but retains its gas-barrier performance when the molecules are not energized. The permeation process is nondestructive. Molecular dynamics-based simulation suggests kinetic energy-mediated chemical reactions catalyzed by common graphene defects as a responsible mechanism.

Reproductive performance after ultrasound-guided transvaginal ethanol sclerotherapy for ovarian endometriotic cysts.

OBJECTIVE: Ultrasound-guided transvaginal ethanol sclerotherapy (TV-EST) has been widely practised in Japan for ovarian endometriotic cysts. We investigated the possible adverse effects of TV-EST for ovarian endometriotic cysts on reproductive performance. PATIENTS AND METHODS: We reviewed retrospectively medical records and compared clinical outcomes of 45 subfertile women who underwent TV-EST for ovarian endometriotic cysts (Study group) with those of 65 subfertile women without ovarian endometriotic cysts (Comparison group). Patients were followed up monthly for 24 months. Serum levels of LH, FSH, CA125 and CA19-9 were determined before and after TV-EST. RESULTS: No complications associated with TV-EST were observed. There were no differences in the numbers of pregnancies (47% (21/45) versus 39% (25/65)), term deliveries (76% (16/21) versus 76% (19/25)), abortions (19% (4/21) versus 24% (6/25)), retrieved oocytes, or quality of embryos between the Study and Comparison groups, respectively. The serum levels of LH and FSH did not increase after TV-EST. The serum levels of CA125 and CA19-9 did not significantly decrease after TV-EST. Ovarian cysts recurred in six (13.3%) of the 45 women 5.2+/-3.9 months after TV-EST. CONCLUSION: Although only a small number of women were studied, our observational study suggested that TV-EST appeared not to adversely affect reproductive performance in subfertile women with ovarian endometriotic cysts.

Chromosome analysis by spectral karyotyping of spermatozoa from an oligoasthenozoospermic carrier of a 10; 21 reciprocal translocation.

Cytogenetic analysis of germ-line cells prior to intracytoplasmic sperm injection (ICSI) treatment is thought to be necessary for infertile males with an identified chromosomal abnormality. We analyzed the chromosomal karyotype of human spermatozoa from an oligoasthenozoospermic carrier of a reciprocal translocation t(10; 21). Cytogenetic analysis of 39 spermatozoa was performed by spectral karyotyping (SKY) and by ICSI into mouse oocytes. The motile morphologically normal spermatozoa were injected into mouse oocytes. Of these spermatozoa, 38 (97.4%) were activated. Twenty-one (53.8%) of the activated oocytes formed two pronuclei. Metaphase chromosome spreads from 13 spermatozoa were analyzed. Only one spermatozoon was normal and 2 spermatozoa exhibited balanced translocation. Nine and one spermatozoa showed abnormalities related and unrelated to the translocation, respectively. The numbers of normal/balanced spermatozoa were lower than those in previous reports analyzing reciprocal translocations using a previously described technique involving penetrated golden hamster oocytes. After genetic counseling with the carrier and his partner, ICSI treatment was performed. Healthy female and male infants were delivered at 37 weeks gestation via a Caesarean section. The female infant was a carrier of the reciprocal translocation and the male infant was confirmed normal on prenatal diagnosis at 16 weeks gestation. For genetic counseling prior to ICSI treatment, the incidence of unbalanced type spermatozoa after swim-up or Percoll gradient treatment should be investigated and discussed with couples having fertility problems related to oligozoospermia autosomal structural abnormalities.

Doubling time of urine human chorionic gonadotropin after assisted reproductive technology.

In the present study, we measured urinary hCG after assisted reproductive technology to accurately calculate normal doubling time (DT) of hCG, and we compared DT values with prognosis of pregnancy. We clarified the correlation between normal DT values, calculated from urinary hCG levels, and viable and nonviable pregnancies.