Publications by authors named "Atsuko Sekiguchi"

In this work, we demonstrate controlled introduction of O-functional groups on commercial carbon nanotube fibers (CNTFs) with different nanotube morphologies obtained by dry- and wet-spinning by treatment with gaseous ozone (O₃(g)). Our test samples were (1) wet-spun fibers of smalldiameter (1-2 nm) singlewall (SW)-CNTs and (2) dry-spun fibers containing large-diameter (20 nm) multiwall (MW)-CNTs. Our results indicate that SW-CNTFs undergo oxygenation to a higher extent than MW-CNTFs due to the higher reactivity of SW-CNTs with a larger curvature strain.

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We present research progress made in developing copper/carbon nanotube composites (Cu/CNT) to fulfil a growing demand for lighter copper substitutes with superior electrical, thermal and mechanical performances. Lighter alternatives to heavy copper electrical and data wiring are needed in automobiles and aircrafts to enhance fuel efficiencies. In electronics, better interconnects and thermal management components than copper with higher current- and heat-stabilities are required to enable device miniaturization with increased functionality.

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Background: Polycystic ovary syndrome (PCOS) is a common ovulatory disorder that can be induced by sodium valproate (VPA).

Patient: We report a case of PCOS that developed in a 15-year-old girl with idiopathic epilepsy after she took VPA. VPA administration stopped her seizures, but it also led to weight gain and amenorrhea, and the patient was diagnosed with PCOS on the basis of diagnostic imaging and serological examination results.

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Although cervical dilatation curves are crucial for appropriate management of labor progression, abnormal labor progression and obstetric interventions were included in previous and widely-used cervical dilatation curves. We aimed to describe the cervical dilatation curves of normal labor progression in pregnant Japanese females without abnormal labor progression and obstetric interventions. We completed retrospective obstetric record reviews on 3172 pregnant Japanese females (parity = 0, n = 1047; parity = 1, n = 1083; parity ≥ 2, n = 1042), aged 20 to 39 years old at delivery, with pregravid body mass indices of less than 30.

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We report ultralong conducting lightweight multiwall carbon nanotube (MWCNT)-Cu composite wires with MWCNTs uniformly distributed in a continuous Cu matrix throughout. With a high MWCNT vol% (40-45%), the MWCNT-Cu wire density was 2/3 that of Cu. Our composite wires show manufacturing potential because we used industrially compatible Cu electrodeposition protocols on commercial CNT wires.

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Aim: The aim of the present study was to elucidate the clinical characteristics of pregnancy-associated maternal deaths.

Methods: We performed a retrospective analysis with medical records and autopsy reports of cases of pregnancy-associated deaths. We collected information on all maternal deaths related to pregnancy that occurred in 3 hospitals affiliated with Nippon Medical School in Japan from January 1, 1984, to December 31, 2014.

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A method for the selective semiconducting single-walled carbon nanotube (SWCNT) growth over a continuous range from 67% to 98%, within the diameter range of 0.8-1.2 nm, by the use of a "catalyst conditioning process" prior to growth is reported.

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New lithographically processable materials with high ampacity are in demand to meet the increasing requirement for high operational current density at high temperatures existing in current pathways within electronic devices. To meet this demand, we report an approach to fabricate a high ampacity (∼100 times higher than Cu) carbon nanotube-copper (CNT-Cu) composite into a variety of complex nano-scale, planar and multi-tiered current pathways. The approach involved the use of a two-stage electrodeposition of copper into a pre-patterned template of porous, thin CNT sheets acting as the electrode.

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Clothes represent a unique textile, as they simultaneously provide robustness against our daily activities and comfort (i.e., softness).

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Objective: To assess the safety of various methods of induced abortion when used before 12 weeks of pregnancy in Japan.

Methods: A retrospective study was undertaken of induced abortions conducted between January 1 and December 31, 2012. Questionnaires were sent to 4154 institutions that employed doctors who were licensed to conduct induced abortions.

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Aim: The aim of this study was to elucidate the clinical characteristics and risk factors for amniotic fluid embolism (AFE).

Methods: We performed a retrospective case study analysis of patients using medical records and autopsy records. The diagnosis of AFE was based on the presence of clinical symptoms using Clark's criteria and autopsy results.

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Background: To evaluate whether consecutive cervical length measurements can predict preterm cesarean section in women with complete placenta previa.

Methods: Seventy-one women with complete placenta previa were retrospectively categorized into women who delivered preterm due to massive hemorrhage (the preterm cesarean section group, n = 28) and those delivered at term (the control group, n = 43). Maternal characteristics, delivery outcomes, and cervical lengths serially measured at least every 2 weeks from 24 weeks' gestation until delivery were compared.

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Ambiguous genitalia (AG) is a morphological diagnosis defined as genitalia not typical of a male or female. Findings mimicking AG, such as penoscrotal anomalies, anorectal malformations, and perineal lipomatous tumors, may prevent accurate identification of the fetal sex. We report a case of bifid scrotum and anocutaneous fistula associated with a perineal lipomatous tumor complicated by temporary bilateral cryptorchidism in utero, which were findings mimicking AG.

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Purpose: To evaluate whether type and location of placenta previa affect risk of antepartum hemorrhage-related preterm delivery.

Methods: We retrospectively studied 162 women with singleton pregnancies presenting placenta previa. Through observation using transvaginal ultrasound the women were categorized into complete or incomplete placenta previa, and then assigned to anterior and posterior groups.

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Increased portability, versatility and ubiquity of electronics devices are a result of their progressive miniaturization, requiring current flow through narrow channels. Present-day devices operate close to the maximum current-carrying-capacity (that is, ampacity) of conductors (such as copper and gold), leading to decreased lifetime and performance, creating demand for new conductors with higher ampacity. Ampacity represents the maximum current-carrying capacity of the object that depends both on the structure and material.

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We illustrate three cases of isolated congenital lymphangioma (CL). Fetal ultrasound (US) demonstrated uniloculated cystic masses that changed to multiloculated, subcutaneous, hypoechoic, avascular cystic masses with thin septations without solid components. Case 1: CL of the right forearm; Case 2: CL of the right hypochondrium; and Case 3: CL of the left upper posterior back.

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Cesarean scar pregnancy is one of the rare types of ectopic pregnancy. Ultrasonography enables early diagnosis and the successful preservation of the uterus. However, the correct diagnosis of cesarean scar pregnancy can be difficult in some cases.

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A rational torsion sensing material was fabricated by wrapping aligned single-walled carbon nanotube (SWCNT) thin films onto the surface of a rod with a predetermined and fixed wrapping angle without destroying the internal network of the SWCNTs within the film. When applied as a torsion sensor, torsion could be measured up to 400 rad/meter, that is, more than 4 times higher than conventional optical fiber torsion sensors, by monitoring increases in resistance due to fracturing of the aligned SWCNT thin films.

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Dacryocystocele is caused by nasolacrimal duct obstruction and results in cystic dilatation of the proximal part of the nasolacrimal duct, which is located inferomedial to the orbit, leading to fluid accumulation. It is important to consider that persistent congenital bilateral dacryocystoceles may cause neonatal nasal obstruction resulting in respiratory difficulty, and large dacryocystoceles may require surgical drainage. Ultrasonography demonstrates that congenital bilateral dacryocystoceles and normal eyeballs prenatally resemble two pairs of cystic "lesions" of different sizes.

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We report a general approach to overcome the enormous obstacle of the integration of CNTs into devices by bonding single-walled carbon nanotubes (SWNTs) films to arbitrary substrates and transferring them into densified and lithographically processable "CNT wafers". Our approach allows hierarchical layer-by-layer assembly of SWNTs into organized three-dimensional structures, for example, bidirectional islands, crossbar arrays with and without contacts on Si, and flexible substrates. These organized SWNT structures can be integrated with low-power resistive random-access memory.

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Aim: Intrapartum management guidelines based on fetal heart rate classification comprising a 5-tier system (Levels 1-5) was proposed by the Perinatology Committee of the Japan Society of Obstetrics and Gynecology (JSOG). This study aimed to assess the reproducibility and clinical usefulness of this classification.

Methods: For assessing intraobserver and interobserver reproducibility in the interpretation of fetal heart rate tracing, 2 obstetricians reviewed 247 fetal heart rate tracings using the JSOG classification (Level 1, normal; Level 2, benign variant; Level 3, mild variant; Level 4, moderate variant; and Level 5, severe variant) and a subjective 3-tier classification (normal, equivocal, and ominous).

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The aim of our study was to use brachial-ankle pulse wave velocity (baPWV) measurements to noninvasively assess the effect of exercise training on arterial stiffness in normal pregnant women. Arterial stiffness was assessed at the beginning of the early second trimester of pregnancy and 1 month after delivery in 17 women with normal singleton pregnancies who exercised regularly throughout pregnancy: 81 matched controls were used for comparison. No significant differences were observed in baPWV between the exercise and control groups at the beginning of the second trimester.

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