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1.
ACS Appl Mater Interfaces ; 11(32): 29408-29415, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31328497

RESUMO

Electrochemical metallization-based threshold switching devices with active metal electrodes have been studied as a selector for high-density resistive random access memory (RRAM) technology in crossbar array architectures. However, these devices are not suitable for integration with three-dimensional (3D) crossbar RRAM arrays due to the difficulty in vertical stacking and/or scaling into the nanometer regime as well as the asymmetric threshold switching behavior and large variation in the operating voltage. Here, we demonstrate bidirectional symmetric threshold switching behaviors from a simple Pt/Ag-doped HfOx/Pt structure. While fabricating the Pt/Ag-doped HfOx/Pt film using a 250 nm hole structure, filaments composed of Ag nanoclusters were constructed through a low-temperature (∼200 °C) hydrogen annealing process where the shape of the film in a nanoscale via a hole structure was maintained for integration with 3D stackable crossbar RRAM arrays. Finite Ag filament paths in the HfOx layer led to uniform device-to-device performances. Moreover, we observed that the hydrogen annealing process reduced the delay time through the reduction of the oxygen vacancies in the HfOx layer. Consequently, the proposed Pt/Ag-doped HfOx/Pt-based nanoscale selector devices exhibited excellent performance of high selectivity (∼105), ultralow OFF current (∼10 pA), steep turn-on slope (∼2 mV/decade), and short delay time (3 µs).

2.
ACS Appl Mater Interfaces ; 9(49): 43336-43342, 2017 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-29139293

RESUMO

Crossbar arrays (CBAs) with resistive random access memory (ReRAM) constitute an established architecture for high-density memory. However, sneak paths via unselected cells increase the total power consumption of these devices and limit the array size. To eliminate such sneak-path problems, we propose a Ti/GaOx/NbOx/Pt structure with a self-rectifying resistive-switching (RS) behavior. In this structure, to reduce the operating voltage, we used a Ti/GaOx stack to increase the number of trap sites in the RS GaOx layer through interfacial reactions between the Ti and GaOx layers. This increase enables easier carrier transport with reduced electric fields. We then adopted a NbOx/Pt stack to add rectifying behavior to the RS GaOx layer. This behavior is a result of the large Schottky barrier height between the NbOx and Pt layers. Finally, both the Ti/GaOx and NbOx/Pt stacks were combined to realize a self-rectifying ReRAM device, which exhibited excellent performance. Characteristics of the device include a low operating voltage range (-2.8 to 2.5 V), high on/off ratios (∼20), high selectivity (∼104), high operating speeds (200-500 ns), a very low forming voltage (∼3 V), stable operation, and excellent uniformity for high-density CBA-based ReRAM applications.

3.
J Menopausal Med ; 21(2): 112-4, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26356509

RESUMO

Premature ovarian failure (POF) is a condition in which the ovarian functions of hormone production and oocyte development become impaired before the typical age for menopause. POF and early menopause are present in a broad spectrum of gonad dysgenesis, from a complete cessation of ovarian function to an intermittent follicle maturation failure. Actually POF has been identified as a genetic entity (especially chromosome X), but data on genetic factors of premature menopause are limited. Until now, several cases revealed that inactivation of X chromosomes has an effect on ages of premature menopause and females with balanced or unbalanced X-autosome translocations can have several reproductive problems. On the other hand, there have been a few data that was caused by autosome-autosome translocation can lead. Therefore we report a relevant case of POF with translocation between chromosomes 1 and 4. She had her first menstrual period at the age of 12, and after 7 years she stopped menstruation. Chromosomal analysis showed 46, XX, t (1;4) (p22.3;q31.3). While evaluating this rare case, we could review various causes (especially genetic factors) of POF. To remind clinicians about this disease, we report a case of POF caused by autosome-autosome translocation with a literature review.

4.
J Menopausal Med ; 21(1): 41-6, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26046037

RESUMO

OBJECTIVES: It has been known that there is a difference in anogenital distance (AGD) in the animals and newborn depending on the exposure of androgenic hormones. The anatomical changes occur in the female genitalia in women after menopause. This was pilot study to find out whether the menopause affects AGD. METHODS: We evaluated a total of 50 women targeted for premenopausal and postmenopausal group in each 25 people. AGD was defined as a length between the posterior commissure of labia and anal center. AGD was measured in lithotomy position using sterile paper ruler. In order to control bias of the height and weight, which could influence the AGD, anogenital index (AGI) is defined as the weight divided by the AGD value. We used a Mann-Whitney U test to analyze the relationship between AGD and menopause for statistical analysis. RESULTS: AGD was significantly longer in premenopausal women compared to postmenopausal women (34.8 ± 6.4 vs. 30.3 ± 6.6, P = 0.019). AGI was significantly higher in premenopausal women than postmenopausal women (1.7 ± 0.4 vs. 1.3 ± 0.3, P ≤ 0.000). CONCLUSION: The changes of AGD and AGI in postmenopausal women demonstrated to have potential to be used as on scale predicting the physical changes that may occur after menopause. This study could be used as the cornerstone of a large-scale studies in the future.

6.
J Menopausal Med ; 21(3): 160-4, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26793682

RESUMO

Mucinous borderline ovarian tumors (BOTs) occur most often in women between the ages of 20 and 30. Early-stage detection of the condition has a more favorable prognosis. In this case report, the authors present an elderly 93-year old woman who visited our hospital due to severe abdominal pain after being diagnosed with a pelvic mass 2 years ago and not undergoing any treatment since the diagnosis was made. She underwent emergency left salpingo-oophorectomy and was diagnosed with mucinous BOT according to biopsy results.

7.
J Menopausal Med ; 21(3): 171-4, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26793684

RESUMO

Uterine serous adenocarcinoma (USC) is rare and invasive cancer. This cancer is more often reported in the ovary, the fallopian tube, and the endometrium than uterine cervix. No matter where the tumor is located, the tumor exhibits similar histological characteristics. So when uterine cancer is proven to be serous adenocarcinoma, it is necessary to see if the tumor originated from ovary or endometrium and invaded the cervix. We report a case of a 73-year-old postmenopausal woman with USC arising near the internal os of endocervical canal, clinically misdiagnosed as uterine cervix cancer.

8.
J Menopausal Med ; 20(1): 32-4, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25371889

RESUMO

In gynecology, endosalpingiosis is a benign condition in which the fallopian tube-like epithelium is found outside the fallopian tube. The thirty-four point five percent of endosalpingiosis cases have concurrent endometriosis and 40% of the endosalpingiosis group are in postmenopausal states. In contrast with endometriosis, there are no significant links between infertility, chronic pelvic pain and endosalpingiosis. The symptoms of endosalpingiosis are not yet settled. Endosalpingiosis is almost always an incidental finding; it is commonly found through microscopic examinations, and is then confirmed by pathologists for excision and biopsy. Therefore, the clinical differential diagnosis of an intramural mass is more important for clinicians when discussing further surgery with the patients. We report case of woman who has endosalpingiosis and is presented with vaginal bleeding. We first suspect the disease during physical examination. Under the impression of pelvic mass, laboratory tests and radiological images of contrast enhanced chest computer tomography are taken. Images show multisepted cystic masses in left adnexa. To rule out the pelvic mass, we executed exploratory laparotomy. Pathologic results show endosalpingiosis near the ovary section. But the endosalpingiosis, is not generally considered a pathology, and thus, no treatment is necessary.

9.
J Menopausal Med ; 20(2): 69-74, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25371896

RESUMO

OBJECTIVES: To evaluate the prevalence of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) of perimenopausal women at a university hospital along with their menstrual characters. METHODS: A questionnaire survey regarding premenstrual symptoms was carried out in 100 perimenopausal women (43 to 53, years). The pattern of menstruation and, the intensity of dysmenorrhea were assessed; and further, the symptoms were classified according to their number, intensity, and persistence. The PMS criteria of American College of Obstetrics and Gynecology (ACOG) and PMDD criteria by American Psychiatric Association (APA) were evaluated. RESULTS: The approximate prevalence of PMS criteria was 95% and that of PMDD criteria was 23%. The most dominant symptoms were 'breast tenderness', 'abdominal bloating', 'and headache'. PMDD was significantly associated with the severity of dysmenorrhea (P = 0.020). There was no significant relation with age, height, weight, body mass index and the cycle of menstruation. CONCLUSION: Most women experience PMS and PMDD, which and have a significant impact on the activity of perimenopause women. However in most women that do not know well about PMS and PMDD. We should educate and inform women of PMS and PMDD, thus helping them increase their quality of life.

10.
J Menopausal Med ; 20(2): 80-3, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25371898

RESUMO

Sclerosing stromal tumor (SST) of the ovary is a rare tumor derived from the sex cord stroma. This tumor was first described by Chalvaridjian and Scully in 1973. SST of the ovary is prevalence of 1.5% to 6% of ovarian stromal tumors. Patients are most commonly diagnosed in their 20s and 30s. There have been reports of SST postmenopausal women aged 65-, 67-, and 71 in the Republic of Korea; however, no report of this disease has been reported in women older than 80. In this study, we would like to report an 80-year-old postmenopausal woman who did not previously complain of any symptoms, and was finally diagnosed with SST. She was involved in a traffic accident, and huge pelvic mass was found during the evaluation of intra-abdominal hemorrhage. Total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed ; a final pathologic diagnosis reported SST.

11.
J Bone Metab ; 20(1): 25-30, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-24524052

RESUMO

BACKGROUND: The Osteoporosis Health Belief Scale (OHBS) is a 42-item questionnaire designed to assess susceptibility, seriousness, calcium benefits, calcium barriers, exercise benefits, exercise barriers, and health motivation related to osteoporosis. We aimed to evaluate its psychometric properties to enable the provision of educational tips regarding osteoporosis. METHODS: All women who had visited the department of obstetrics and gynecology (OBGYN) and whose bone mineral density was measured from January 2010 to December 2011 were enrolled by interview using the OHBS. We also evaluated the women's general clinical characteristics. RESULTS: One hundred seventy-seven women were enrolled in the present study. In the present study, the barriers to calcium intake subscale had the lowest mean score (15.03±3.02), and the Benefit of Exercise subscale had the highest (23.02±3.03). The scores for participants in their 20s were significantly higher than scores for those in their 70s on the Benefits of Exercise subscale and Barriers to Exercise subscale (P=0.014 and P=0.022, respectively). CONCLUSIONS: Education for health motivation to prevent osteoporosis is important for young women. Additional systematic education programs are needed for the general population.

12.
J Bone Metab ; 20(2): 115-8, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24524068

RESUMO

Osteoporosis is mainly a problem in postmenopausal women. However, we had a case of postpartum compression fracture associated with osteoporosis. A 42-year-old multiparous woman had undergone tertiary cesarean section without complications 1 month before. She was breast-feeding her baby and had no other bone-related complication history. She did not exercise on a regular basis. She experienced back pain abruptly and was diagnosed with a recent compression fracture of T12, L1, and L3. We evaluated this rare case of postpartum osteoporosis and compression fracture.

13.
J Menopausal Med ; 19(3): 151-3, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25371883

RESUMO

Endometriosis is a benign disease and an estrogen-dependent disease. Postmenopausal endometriosis is rare, because the absence of estrogenic hormone production. We report a case of endometriosis presenting in a postmenopausal woman with no history of endometriosis before hormone replacement therapy.

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