Chang Hyo Kim

Tailoring the pore structure of carbon nanofibers for achieving ultrahigh-energy-density supercapacitors using ionic liquids as electrolytes

The low energy density of commercially available activated carbon-based supercapacitors has limited their widespread applications. In the current work, we demonstrated fabrication of carbon nanofiber-based supercapacitors that exhibited ultra-high energy density by rationally tailoring their pore structure in an ionic liquid system. To gain control on the pore structure, three different methods were employed for the synthesis of an electrospinning-derived freestanding carbon nanofiber web. They are incorporation of a pore generator (i.e., tetraethyl orthosilicate) in the electrospinning step, physical activation (e.g., H2O or CO2), and hydrogen treatment. We observed finely tuned pore sizes ranging from 0.734 to 0.831 nm and accompanying changes in BET surface areas ranging from 1160 to 1624 m2 g−1. The entrapped TEOS within the electrospun organic nanofiber web provided high tuning ability of the pore structure in the following carbonization step, and decreased the activation energy of the pore formation. Both high specific capacitance (161 F g−1) and ultra-high energy density (246 W h kg−1) were achieved when the pore size on the surface of carbon nanofibers matched with the ionic size of the electrolyte. Our results demonstrate the importance of a finely tuned pore structure to secure high-temperature operable carbon nanofiber-based supercapacitors with ultrahigh energy density using ionic liquids as electrolytes.

Rationally engineered surface properties of carbon nanofibers for the enhanced supercapacitive performance of binary metal oxide nanosheets

The hybridization of an electrochemically active metal oxide with electrically conductive carbon nanofibers (CNFs) has been utilized as a solution to overcome the energy density limitation of carbon-based supercapacitors as well as the poor cyclic stability of metal oxides. Herein, we have demonstrated the growth of binary metal oxide nanosheets on the engineered surface of CNFs to fully exploit their electrochemical activity. Metal oxide nanosheets were observed to grow vertically from the surface of CNFs. The high structural toughness of the CNF–metal oxide composite under strong sonication indicated strong interfacial binding strength between the metal oxide and the CNFs. The rationally designed porous CNFs presented a high specific surface area and showed high capacity for adsorbing metal ions, where the active edge sites acted as anchoring sites for the nucleation of metal oxides, thereby leading to the formation of a well dispersed and thin layer structure of binary metal oxide nanosheets. Excellent electrochemical performance (e.g., specific capacitance of 2894.70 F g−1 and energy density of 403.28 W h kg−1) was observed for these binary metal oxide nanosheets, which can be attributed to the large increase in the accessible surface area of the electrochemically active metal oxide nanosheets due to their homogeneous distribution on porous CNFs, as well as the efficient charge transfer from the metal oxide to the CNFs facilitated the improvement in the performance.

The effect of a Foley catheter balloon on cervical ripening

The Foley catheter balloon may affect cervical ripening through changes in biochemical mediators by immunoassay and immunohistochemistry, when it is used for pre-induction cervical ripening. The aim of the study was to evaluate the changes in the biochemical mediators from the extra-amniotic space and immunohistochemistry in ripened cervical tissue after the insertion of a Foley catheter balloon (FCB) for pre-induction cervical ripening. A total of 18 pregnant women with a Bishops score < 6, who were undergoing labour induction, were evaluated in this prospective study. The FCB was irrigated with 10 ml of phosphate buffered saline and the irrigant was collected 0, 2, 4 and 8 h after placement of the FCB or until spontaneous expulsion of the FCB occurred. Irrigant specimens were also collected from 10 spontaneous labouring (SL) women in the active phase of labour. The levels of interleukin (IL)-6, IL-8, matrix metalloproteinase (MMP)-8 and NO were measured. Cervical specimens were obtained from 12 women, including four undergoing induction; four SL and four non-pregnant (NP) women. Immunohistochemical staining was performed to localise hyaluronic acid synthase (HAS)-1, IL-6, IL-8, MMP-8, endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS). Results showed that the levels of IL-6, IL-8, and MMP-8 significantly increased over time in FCB group (p < 0.01). In the immunohistochemical analysis of cervical tissues, immunoreactivity of HAS-1 in the after FCB group was stronger than any of the other groups. The protein expressions of IL-6, IL-8, MMP-8, eNOS and iNOS were more prominent in the after FCB and SL groups than in the NP and the before FCB groups. iNOS was only observed in the after FCB and SL groups. It was concluded that FCB may affect cervical ripening through changes in biochemical mediators by immunoassay and immunohistochemistry, when it is used for pre-induction cervical ripening.

IT02. TiO2 nanoparticles loaded on graphene/carbon composite nanofibers by electrospinning for increased photocatalysis

Graphene/carbon composite nanofibers (GCNFs) with attached TiO2 nanoparticles (TiO2-GCNF) were prepared, and their photocatalytic degradation ability under visible light irradiation was assessed. They were characterized using scanning and transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffuse spectroscopy. The results suggest that the presence of graphene embedded in the composite fibers prevents TiO2 particle agglomeration and aids the uniform dispersion of TiO2 on the fibers (Fig.1). In the photo-degradation of methylene blue, a significant increase in the reaction rate was observed with TiO2-GCNF materials under visible light. This increase is due to the high migration efficiency of photo-induced electrons and the inhibition of charge-carrier recombination due to the electronic interaction between TiO2 and graphene [1,2](Fig.2). The TiO2-GCNF materials could be used for multiple degradation cycles without a decrease in photocatalytic activity.

Comparison of the clinical and quality-of-life outcomes after the inside-out TVT-O procedure with or without concomitant transvaginal gynaecological surgery

The study was undertaken to compare the clinical and quality-of-life (QoL) outcomes of the inside-out transobturator vaginal tape (TVT-O)-only procedures and TVT-O procedures with concomitant transvaginal gynaecological surgery for the treatment of stress urinary incontinence (SUI). A review of charts from January 2006 to March 2010 identified 305 patients with urodynamic stress incontinence for whom we performed the TVT-O. Of the initial 305 patients, 272 (89.2%) were re-examined for complications 1 month, 4 months, 1 year and 2–4 years postoperatively (122 TVT-O only; 150 TVT-O + other transvaginal gynaecological surgery). They were also evaluated with the Urogenital Distress Inventory Questionnaire (UDI-6) and the Incontinence Impact Questionnaire (IIQ-7) 1–4 years after the procedure. The median follow-up was 37.3 months. The success rate was 89.3% in the TVT-O-only group vs 93.3% in the TVT-O with concomitant gynaecological surgery group (p =0.729). The QoL score was quite good for 91.8% of the TVT-O-only patients and for 96.7% of the TVT-O with concomitant gynaecologic surgery patients (p =0.405). In conclusion, gynaecological operations performed concomitantly with the TVT-O procedure do not affect the clinical and QoL outcomes of the TVT-O procedure.

Electro-conductively deposited carbon fibers for power controllable heating elements

Carbon fibers are considered as one of the promising heating elements in various industrial applications because of their excellent thermal stability and electrical conductivity. In order to achieve controllability of the power output, gas-phase carbon deposition was carried out on the surface of carbon fibers by flowing a mixture of liquefied petroleum gas and hydrogen via electro-conduction chemical vapor deposition. We confirmed the tuning ability of the temperature ranging from 800 to 1330 °C. The microtexture of the deposited carbon was sequentially changed; the initial layer with small-sized domains, the intermediate layer with medium crystallinity, and the top layer with large-sized domains and high crystallinity. However, the linear decrease in the electrical conductivity of the heating elements was ascribed to the change in the growing direction of the crystallites from a longitudinal to a perpendicular direction with respect to the fibers. The wide range of power output for our carbon fiber composites from 270 to 448 W at 50 V will be useful for various industrial electric heating applications.

P05.06: Antenatal diagnosed occipital calcification: a case of craniosynostosis

Premature ossification and closure of the cranial sutures results in the abnormal shape and size of the skull. This can cause compression on cranial nerves and increased pressure on growing brain. In most cases, only one suture is affected and the condition is isolated and sporadic. However, in a minority of cases, closure of multiple sutures is possible and associated anomalies are present. The most frequent craniosynostosis is due to closure of the sagittal suture, which is responsible for about half of the cases, resulting in an elongated head (scaphocephaly). The second most frequent type is due to closure of the coronal suture that results in a very flat, recessed forehead (brachycephaly). We report a rare case of craniosynostosis in the sagittal and bilateral lambdoid sutures. Ultrasound examinations were performed in the ACCUVIX XQ (Medison, Seoul, Korea). Antenatal sonographic finding was normal except occipital calcification. Fetus occipital area was calcified and protrudent. Fetal brain MRI was checked and it was not detected any pathology finding. Cesarean section was performed at 37 weeks gestation. 2990g, male was born. He had abnormal scalp shape and small head. Craniosynostosis with sagittal and both lambdoid sutures and small cranial volume was detected in brain 3 dimensional CT. But brain MRI was not any evidence of brain anomaly. So we report our experience with a brief review of literature.

OP19.01: Atosiban, magnesium sulfate and ritodrine therapy for preterm labor: effects on uterine, fetal umbilical and middle cerebral artery Doppler parameters in the first 24 hours

Background: Cardiovascular abnormalities are common in the recipient twin in TTTS. In the donor, except for altered umbilical arterial flow, no gross cardiovascular changes are typically seen. Selective laser photocoagulation therapy (SLPT) improves outcome and can reverse many of the cardiovascular abnormalities noted in the recipient, however its impact on the donor twin heart has not been extensively studied. Objective: To investigate the effects of SLPT for TTTS on the cardiovascular status of the donor twin. Methods: Pre and post-operative fetal echos from 54 patients who underwent SLPT for TTTS Stage 2 or higher from June 2007 to February 2009 were reviewed. Cardiothoracic ratio (CTR), Doppler tricuspid and mitral E and A peak inflow velocities, umbilical artery (UA) and middle cerebral artery (MCA) pulsatility indices (PI), and myocardial performance indices (MPI) of the donor twin, were compared before and after SLPT. Presence or absence of pericardial effusion (PE) and tricuspid or mitral regurgitation were also noted. Results: CTR increased significantly as did mitral and tricuspid valve velocities, suggesting an increase in volume load. UA PI increased, but MCA PI remained unchanged. In select donors RV MPI increased substantially, however there was no difference for the group as a whole. Postoperatively, over 20% of donors developed a significant PE; nearly 50% developed tricuspid or mitral regurgitation. Conclusions: Important cardiovascular abnormalities develop in the donor twin following SLPT. The origin of these findings are unclear, but may be related to the insult of acute, rapid volume load in a previously volume depleted fetus. Serial fetal echo follow up of both donor and recipient for cardiovascular abnormalities after SLPT is warranted.