도료의 국제경쟁력 실태분석 및 전망

이치규 한국공업화학회 1992 한국공업화학회 심포지엄 Vol.0 No.-

A comparative study of ultra-trace-level uranium by thermal ionization mass spectrometry with continuous heating: Static and peak-jumping modes

이치규,박난희,박진규,임상호 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

For ensuring nuclear safeguards, we report the analytical signal-detection performance of thermal ionization mass spectrometry (TIMS) with continuous heating for the measurement of isotopic ratios in samples containing ultra-trace amounts of uranium. As methods for detecting uranium signals, peakjumping mode using a single detector and static mode using multiple detectors were examined with U100 (10% 235U-enriched) uranium standard samples in the femtogram-to-picogram range. Uranium isotope ratios, n( 235U)/n( 238U), were measured down to levels of 1 fg and 3 fg in static and peak-jumping modes, respectively, while n( 234U)/n( 238U) and n( 236U)/n( 238U) values were measured down to levels of 100 fg in both modes. In addition, the dependency of the 238U signal intensity on sample quantity exhibited similar tendencies in both modes. The precisions of the isotope ratios obtained in the static mode over all sample ranges used in this study were overall slightly higher than those obtained in peakjumping mode. These results indicate that isotope ratio measurements by TIMS with continuous heating are almost independent of the detection method, i.e., peak-jumping mode or static mode, which is characteristic of isotope-ratio measurements using the TIMS method with continuous heating. TIMS with continuous heating is advantageous as it exhibits the properties of multiple detectors within a single detector, and is expected to be used in various fields in addition to ensuring nuclear safeguards

Accurate determination of minor isotope ratios in individual plutonium – uranium mixed particles by thermal ionization mass spectrometry

이치규,박진규,임상호 한국원자력학회 2018 Nuclear Engineering and Technology Vol.50 No.1

Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of 0.6e3.3 mmwere performed using thermal ionization mass spectrometry with a continuous heating method to verifyits effectiveness for the accurate analysis of minor isotopes without sample pretreatment. The mixedparticles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium(U010, 235U 1% enriched) reference materials. The isotope ratios for plutonium in the individual mixedparticles, including 238Pu/239Pu, 241Pu/239Pu as well as 240Pu/239Pu, and 242Pu/239Pu, were in goodagreement with the certified values despite the isobaric interference of 238U and 241Am. The isotoperatios for uranium in the mixed particles also agreed well with the certified values within the range oferror. However, the isotope ratios for minor isotopes, such as 234U and 236U, in the particles with diametersof less than approximately 1.8 mm could not be measured because numbers of 234U and 236Uatoms in analyzed particles are too low. These results indicate that thermal ionization mass spectrometrywith a continuous heating method is applicable for the analysis of trace amounts of plutonium isotopes,including 238Pu and 241Pu, despite the presence of the respective isobars 238U and 241Am in themicrosamples.

외이도 종물로 발견된 청신경종 1예

이치규,윤석만,박계훈 대한이비인후과학회 2009 대한이비인후과학회지 두경부외과학 Vol.52 No.4

Acoustic neuromas arise frequently within the internal auditory canal and cerebellopontine angle. Rarely, a schwannoma may occur primarily within the labyrinth or may extend secondarily into the labyrinth from the internal auditory canal. The authors experienced a very rare case of acoustic neuroma presenting as a tumor of the external auditory canal in a 43 year-old woman. Tumor was removed by a transotic approach and found to be present in the external auditory canal, middle ear, labyrinth, internal auditory canal and cerebellopotine angle. Subtotal resection of the tumor was performed due to severe adhesions to the facial nerve in the proximal internal auditory canal. Serial magnetic resonance imaging is planned to follow up the residual tumor.

Protective Effect of Minocycline Against Cisplatin-induced Ototoxicity

이치규,신장인,조양선 대한이비인후과학회 2011 Clinical and Experimental Otorhinolaryngology Vol.4 No.2

Objectives. Cisplatin, a widely used chemotherapeutic agent, has serious side effects, including nephrotoxicity and ototoxicity. Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory and neuroprotective effects. The purpose of this study was to elucidate the protective effect of minocycline against cisplatin-induced ototoxicity in the auditory hair cell. Methods. The House Ear Institute-Organ of Corti 1 (HEI-OC1) cell line and guinea pigs were used for in vitro and in vivo experiments. Cells were exposed to cisplatin with or without pre-treatment with minocycline. Cell survival was analyzed using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide). Whole-cell lysates were collected and immunoblotted with antibodies against Bcl-2, p-c-Jun, active caspase-3, cleaved poly (ADP-ribose) polymerase (PARP), and apoptosis-inducing factor (AIF). The guinea pigs received intraperitoneal injections of cisplatin alone or following minocycline pretreatment. The auditory brainstem response was tested and the cochleae were harvested and evaluated using scanning electron microscopy. Results. Survival significantly increased in cells pretreated with minocycline compared with cells exposed to cisplatin alone. Cisplatin treatment increased the expression of active caspase 3, p-c Jun, PARP, and AIF, and pretreatment with minocycline attenuated this response. In animal study, the threshold shift by cisplatin injection in the auditory brainstem response was less pronounced in animals pretreated with minocycline. Scanning electron microscopy revealed more severe damage to the outer hair cells at the basal and middle turns than the apical turn. Conclusion. Minocycline partially protects against cisplatin-induced ototoxicity via both caspase-dependent and independent apoptosis pathways.

The efficiency improvement of solution-processed phosphorescent organic light-emitting diodes though a newly designed ancillary ligand

이치규,조우섬,이재욱,제갈영순,진성호 한국고분자학회 2014 한국고분자학회 학술대회 연구논문 초록집 Vol.2014 No.10

Is a Solitary Fibrous Tumor in the External Auditory Canal Benign?

이치규,이현주 대한청각학회 2016 Journal of Audiology & Otology Vol.20 No.2

A solitary fibrous tumor (SFT) is an extremely rare, distinct otological soft-tissue tumor. Only two such tumors in the external auditory canal have been reported. A SFT related to hemangiopericytomas (HPC), which commonly arise in the central nervous system. HPCs act malignant in many cases, while SFTs at other sites are mainly benign. A 25-year-old female presented with highly vascular tumor at the right external auditory meatus and bleeding from the mass when a crust was removed from its surface. After excisional biopsy followed by pre-operative embolization, this tumor confirmed with SFT. The recurrence rate of SFT is very low after complete resection, with a slightly increased risk of recurrence with extrathoracic tumors. We describe the third case of SFT in the external auditory canal and review the literature.

Environmental detection using precise analysis of trace nuclear materials

이치규 한국분석과학회 2022 학술대회논문집 Vol.2022 No.11

두부 외상 후 미로진탕 환자의 임상적 특징

이치규,박계훈 순천향대학교 순천향의학연구소 2017 Journal of Soonchunhyang Medical Science Vol.23 No.2

Objective: Blunt head injury can lead to isolated damage of the inner ear (cochlear labyrinthine concussion) or damage of the otolith organ (vestibular labyrinthine concussion) due to a bone conduction pressure. We evaluated the clinical characteristics of hearing impairment in patients who suffered from a blunt head trauma without any organic problems, including temporal bone fracture or intracranial hemorrhage. Methods: This retrospective study examined 9 patients presenting with hearing impairment after blunt head trauma within recent 5 years. This study included only patients without temporal bone fracture or intracranial hemorrhage. Results: Most patients complained of associated auditory symptoms including tinnitus, dizziness, earfullness, and otalgia. Twelve ears of 9 patients showed sensorineural hearing loss; mild (1 ear), moderate (3 ears), moderate-severe (4 ears), severe (2 ears), and profound (2 ears). After high-dose steroid therapy, 2 ears had a significant hearing gain, but 10 ears showed no improvement of hearing. Conclusion: Blunt head injury is one of the most common causes of the neurologic disorders. It is important to perform thorough assessment of auditory symptoms as soon as possible. Otologic consultation should be sought in all cases for appropriate management.

퀴논 - 디아민 부가물계 고성능 도료용 수지

이치규 ( Chi Giu Lee ) 한국유화학회 1996 한국응용과학기술학회지 Vol.13 No.1

We have prepared diamine-benzoquinone polymer which was known to excellent water proofing, high adhesion strength and good anti-corrosive effect, and have investigate with the possibility of application as a high performance resin for coatings. First of all, the reactivity of diamine-benzoquinone has been described an example of polymer reaction with research trend. The polymer reaction was divided into the polymerization with several diamine-benzoquinone and urethane group. The synthetic resin was shown a high solubility. In case of polymer containing urethane, water absorption content, water proofing and mechanical properties were controlled with the content, water proofing and mechanical properties were controlled with the content of quinone. It was shown that an use of choice was a possible result for various coatings. Diamine-qunone polymer can be used as a new resin for coatings. In addition, the polymer containing a functional group was shown a useful applicability as a high performance resin.