• Tunnel and Underground Space
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• v.25 no.6
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• pp.496-504
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• 2015

Roadheader that excavates ground using pick cutters installed on the cutting head is one of the partial-face machines. A conical cutter among pick cutters is excavation tool decreasing the loss of cutter using tungsten carbide insert at the tip of the cutter and it has been widely used in the roadheaders. In this study, durability performance for three kinds of conical cutters was evaluated in copper mines composed of Manto and conglomerate. After field test, the visual inspection as well as the weight loss measurement of pick cutters was carried out to investigate the damage of pick cutters. In addition, CT scan and SEM were performed to check whether or not crack and apertures in pick cutters. As results, the conical cutter with hardfacing was evaluated as having the best durability performance and it was unable to find cracks in all cutters investigated.

• Korean Journal of Head & Neck Oncology
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• v.15 no.2
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• pp.217-221
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• 1999

Background and Objectives: Subacute necrotizing lymphadenitis or Kikuchi's disease has now become recognized in many parts of the world as a well-defined clinicopathologic entity. It typically affects cervical lymph nodes of young women, and subsides spontaneously within a few months without recurrences. The purpose of this study is to report the clinicopathologic finding, radiologic finding and many laboratory tests to elaborate the criteria that are useful in distinguishing this entity from inflammatory disease, granulomatous disease, lymphoma, malignant disease. Material and Methods: Authors evaluated 22 patients, who were diagnosed as subacute necrotizing lymphadenitis on excisional biopsy or fine needle aspiration cytology with retrospective chart review. Results: The patient population consisted of 21 women and 1 men. The mean age was 25 years old(range 17 to 42 years). All patient had palpable neck mass and associated fever, headache, weight loss, otalgia, diarrhea, night sweating. and associated disorder is dermatitis, hepatitis B, SLE, Hashimoto's thyroiditis, albinism et al. The multiple bilateral involvement of cervical lymph node was 20 cases(91%) and multiple unilateral 18 cases(82%), multiple bilateral 2 cases(9%). Solitary involvement was 2 cases(9%), mean size of involved lymph node was 2.0cm. In laboratory tests, leukopenia 17 cases(72%), elevated ESR 12 cases(54%), elevated GOT, GPT 3 cases(13%). In CT finding, lymph nodes enhanced in homogeneous fashion, and there was no evidence of central necrosis. Conclusion: Subacute necrotizing lymphadenitis, Kikuchi's disease may be easily confused clinically, pathologically, radiologically with malignant lymphoma, inflammatory disease, granulomatous disease. We should consider open biopsy of lymph node in the patient which had unilateral multiple cervical lymph node and in laboratory tests, were leukopenia, elevated ESR, especially in young women. otherwise, result of fine needle aspiration biopsy is nonspecific, excisional biopsy is recommended in order to differentiate other disease.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.21 no.1
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• pp.37-41
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• 2010

Background and Objectives : Transient minor voice changes after thyroidectomy are not infrequent complaints even in cases without any evidence of recurrent laryngeal nerve damage. However, clinical course, diagnosis and management of such voice changes are not fully understood. This study aimed to evaluate the clinical characteristics of minor voice changes after thyroidectomy. We also tried to assess the significance and feasibility of superior laryngeal nerve monitoring and to find out the optimal evaluation tools for such voice changes after thyroidectomy. Materials and Method : Nine adult patients who received total thyroidectomy without evidence of recurrent laryngeal nerve injury were enrolled for this prospective study. Voice evaluations were performed preoperatively and 3 months postoperatively ; acoustic analyses including voice range profile, aerodynamic study, stroboscopic evaluation and subjective voice assessment with questionnaires. The external branch of superior laryngeal nerve was monitored by nerve stimulator after ligation of superior thyroidal vessels. Results: Four of nine patients complained their voice change at 3 months after the surgery. Three of them reported complete recovery of their voice at 6 months after the surgery. Acoustic analysis revealed significant decrease in their phonatory range especially with high tone loss. Questionnaires related to singing was more sensitive than previously well-known "voice handicap index". Stimulation of the superior laryngeal nerve was feasible in most of the cases (94.4%), but it failed to show any correlation with minor voice changes after thyroidectomy. Conclusion : Minor voice changes were not rare events during the first 6 month after thyroidectomy. Decrease in phonatory range with high tone loss and therefore, discomfort in singing was the most common finding. Superior laryngeal monitoring was feasible but it was not a sensitive tool for the prediction of minor voice change after thyroidectomy.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
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• v.61 no.11
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• pp.573-579
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• 2018

Background and Objectives Cochlear dead region (CDR) is a region in the cochlear where hearing loss has occurred due to damage to the inner hair cells and/or neurons. Recently, a subjective test involving a pure-tone test in the presence of threshold-equalizing noise (TEN) was introduced to identify CDR. However, for uncooperative patients, such a subjective method would be unsuitable and objective methods would be needed instead to detect CDR. The acoustic change complex (ACC) is an evoked potential elicited by changes in the ongoing sound. In this study, we developed an objective method of identifying CDR by combining ACC response with a TEN test, namely the TEN-ACC test, and investigated its feasibility in normal-hearing listeners. Subjects and Method Ten normal-hearing subjects participated in this study. All subjects underwent both behavioral TEN test and electrophysiological TEN-ACC test. The stimuli for the TEN-ACC test consisted of TEN and embedded pure tones with different frequencies/signals to noise ratios (SNRs). To identify the thresholds, the range SNR of stimulation was varied from 0 to 20 dB, in stages of 4 dB. Results The ACC responses of all subjects who participated in this study were well elicited by stimuli developed for the TEN-ACC test. We confirm that the pure-tones embedded in TEN elicited the objective ACC response. Conclusion The results of this study suggest that the novel TEN-ACC test can be applied to evoke ACC in normal-hearing listeners. Future research should incorporate hearing-impaired listeners to determine the feasibility of the TEN-ACC test as an objective method to identify CDR.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.1
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• pp.253-258
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• 2015

Background: Development of squamous cell cancer of head and neck (SCCHN) is associated with human papillomavirus (HPV) infection, which in turn is closely related with expression of $p16^{INK4A}$. Loss of $p16^{INK4A}$ expression by deletion, mutation, or hypermethylation is common in SCCHN. We here evaluated $p16^{INK4A}$ as a prognostic marker of treatment response and survival in our SCCHN patients with laryngeal, hypopharyngeal or nasopharyngeal cancers. Materials and Methods: 131 patients diagnosed with SCCHN between January 2,2006 and July 17, 2010 were examined for $p16^{INK4A}$. The median age was 60 years (15-82 years). Fifty one patients were stage I-II and 80 were stage III-IV. Immunohistochemical expression of $p16^{INK4A}$ was analyzed in pretreatment paraffin-embedded tumor blocks. The influence of $p16^{INK4A}$ status on disease-free survival, and overall survival after treatment was evaluated. Results: $p16^{INK4A}$ positivity was found in 58 patients (44%). Tumor-positivity for$ p16^{INK4A}$ was correlated with improved disease free survival (70.1 months vs 59 months) and improved overall survival (2, 3 and 5-year values; 77% vs 72%, 70% vs 63% and, 63% vs 55%; respectively). On multivariate analysis, stage was determined as independent prognostic factor for disease-free survival. Conclusions: Stage was the major prognostic factor on treatment response and survival in our patients. $p16^{INK4A}$ status predicts better outcome in laryngeal, hypopharyngeal or nasopharyngeal cancer cases treated with surgery plus adjuvant radiochemotherapy as well as with definitive radiation therapy and/or chemotherapy.

• Archives of Reconstructive Microsurgery
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• v.15 no.2
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• pp.92-100
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• 2006

Radial forearm free flap (RFFF) has been established itself as a versatile and widely used method for reconstruction of the head and neck, although it is still criticized for high mortality of donor site. Delayed wound healing, cosmetic deformity, vascular compromise and potentially reduced wrist function have many plastic surgeons hesitate to adapt it as a first choice in micro-reconstruction. To overcome these drawbacks, some techniques for donor-site repair such as V-Y advancement with full thickness skin graft (FTSG), application of artificial dermis ($Terudermis^{(R)}$) or acellular dermal matrix ($AlloDerm^{(R)}$), and double-opposing rhomboid transposition flap have been reported. Authors performed 4 cases of RFFF in old-aged patients of the head and neck cancer from April 2005 to February 2006. We compared the outcomes of donor site of RFFF which were resurfaced with split thickness skin graft (STSG) only and STSG overlying an $AlloDerm^{(R)}$. Patients were all males ranging from 59 to 74 years old (mean, 67.5). Three of them had tongue cancers, and the other showed hypopharyngeal cancer. All cases were pathologically confirmed as squamous cell carcinomas. We included the deep fascia into the flap, so called subfascially elevated RFFF in three cases, and in the other one, we dissected the RFFF suprafascially leaving the fascia intact. The donor site of the suprafascially elevated RFFF was resurfaced with STSG only. Among three of subfascially elevated RFFFs, donor-sites were covered with thin STSG only in one case, and STSG overlying $AlloDerm^{(R)}$ in two cases. All RFFFs were survived completely without any complication. The donor site of the suprafascially elevated RFFF was taken well with STSG only. But, the partial graft loss exposing brachioradialis and flexor carpi radialis muscle was unavoidable in all the subfascially elevated RFFFs irregardless of $AlloDerm^{(R)}$ application. Considering that many patients of the head and neck cancer are in old ages, we believe the RFFF is still a useful and versatile choice for resurfacing the head and neck region after cancer ablation. Its reliability and functional characteristics could override its criticism for donor site in old-aged cancer patients.

• Journal of Korean Neurosurgical Society
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• v.29 no.9
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• pp.1233-1237
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• 2000

Objectives : In order to evaluate the metabolic changes associated with pericontusional edematous area in mild head injury, proton magnetic resonance spectroscopy(1H-MRS) was performed in mild head injury patients (initial GCS score 13-15) with focal brain contusion. Methods : Seven head injury patients with initial GCS 13-15(3 males and 4 females : age range 15-65 years, mean age 33 years) have underwent 1H-MRS evaluations. The patients were examined within 7 days after injury(n=7) and 2 months after injury(n=5). The region of interest(ROI) was selected in the edematous area adjacent to traumatic brain contusion upon T2-weighted MR images and a corresponding region of the contralateral hemisphere (ROC, region of contralateral corresponding hemisphere) was examined as well. The metabolic ratios of NAA/Cr and lactate/Cr were compared between ROIs, ROCs and control values. Results : In initial NAA/Cr ratios, the values of ROIs were significantly lower than those of the controls(p=0.009), but there was no difference either between ROIs and ROCs(p=0.410) or between ROCs of patients and the control (p=0.199). In lactate/Cr ratios, the ROIs in all seven patients and the ROCs in two showed increased lactate signals. The lactate/Cr ratios of the ROIs were significantly elevated as compared to those of the ROCs(p=0.02) and the control(p=0.015). In two months follow-up, lactate signals were absent or significantly reduced(p=0.015). In no patients, clinical or radiological deterioration has been observed. Conclusion : Our 1H-MRS results demonstrate that there are significant ischemic changes in pericontusional edematous areas as indicated by elevated lactate signals in the patients with mild head injury. But there were no consistent neural loss or dysfunction in these area. There findings suggest that pericontusional edematous areas can be vulnerable to secondary brain insults even in the patients with mild head injury.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6883-6888
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• 2013

Background: Platinum based concurrent chemo-radiation is the de-facto standard of care in the non-surgical management of locally-advanced head and neck cancer of squamous origin. Three-weekly single agent cisplatin at 100 $mg/m^2$ concurrent with radical radiotherapy has demonstrated consistent improvement in loco-regional control and survival. This improvement is however at the cost of considerable hematologic toxicity and poor overall compliance. The routine use of this regime is improbable in developing countries with limited resources. We therefore aimed to determine the safety and efficacy of an alternative regime of weekly cisplatin and concurrent radiotherapy in such patients. Materials and Methods: January-05 and April-12, 188 patients of locally-advanced head and neck cancer of squamous origin were treated with concurrent weekly-cisplatin at $35mg/m^2$ and conventional radiotherapy 60-66Gy/30-33 fractions/5days per week. Results: Overall, 95% patients received planned doses of RT while 74% completed within the stipulated overall treatment time of <50 days. Eighty-two percent received at-least 5 weekly cycles. Grade-III/IV mucositis was seen in 58%/9% respectively, which resulted in mean weight loss of 9.2% from a pre-treatment mean of 54.5 kg. Grade-III hematologic toxicity-0.5%; grade II nephrotoxicity-2.5% and grade III emesis-3% were also seen. Grade-III/IV subcutaneous toxicity-10%/1% and grade-III/IV xerostomia-10%/0% were observed. Complete responses at the primary site, regional nodes and overall disease were seen in 86%, 89% and 83% patients respectively. The median and 5-years disease-free survival were 26 months and 39.4% respectively, while the median and overall survival were 27 months and 41.8% respectively. Conclusions: Weekly-cisplatin at 35 $mg/m^2$ when delivered concurrently with conventional radical RT (at-least 66y/33 fractions) in locally-advanced head and neck cancer is well tolerated with minimal hematologic and neprologic toxicity and can be routinely delivered on an out-patient basis. It is an effective alternative to the standard 3-weekly cisplatin especially in the context of developing countries.

• Journal of the Korean GEO-environmental Society
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• v.15 no.2
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• pp.37-43
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• 2014

Natural disasters such as earthquakes and tsunamis occur suddenly, so that they cause massive loss of lives and property. Especially earthquakes represent a particularly severe threat because of the extensive damage accompanied by them. In Korea, an earthquake-resistant design has been rarely applied to a design or construction of slope. However, in resent years, the researches for earthquake-resistance have been performed because the importance on the earthquake-resistance is perceived and highlighted. Soil nail method, one of the slope stability methods, is excellent for its constructability and cost effectiveness, as compared with other stability methods. Also, this method has been widely used for reinforced construction for slope stability. The studies of soil nail method have been performed on the interaction behavior between nails and slopes as well as the varied load condition such as static load, dynamic load and so on. Nevertheless, there has been minimal research regarding the constraint condition of nail head. In this study, the numerical analysis was performed for identifying effect on slope stability for the constrain condition of the soil nail. The result shows that the resistance of constrained the nail head on reinforced slope is larger compared to the one of unconstrained nail head.

• Progress in Medical Physics
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• v.12 no.2
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• pp.103-112
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• 2001

Purpose: The purpose of this study was to investigate the current status of performing nuclear medicine quality control in korea and to test selected protocols of quality control of nuclear medicine counting system and gamma camera. Materials and Methods: Fifty three hospitals were included to investigate the current status of nuclear medicine quality control in korea. The precision of dose calibrator and thyroid uptake system was measured with Tc-99m 35.52 MBq for 2 minuets and Tc-99m 5.14 MBq for 10 sec every one minute, respectively. The sensitivity of CeraSPECT$^{TM}$ with low energy high resolution parallel hole collimator was measured using two cylindrical phantoms with 15 cm in diameter and 12 cm and 30 cm in heights containing Tc-99m. The correction factor for sensitivity of CeraSPECT$^{TM}$ was calculated using phantom data. The system planar sensitivity, uniformity, count rate and spatial resolution were measured for Varicam gamma camera with low energy high resolution parallel hole collimator using 140 keV centered 20% energy window, 256$\times$256 or 512$\times$512 matrix sizes. Results: The quality control of dose calibrator and well counter were showed poor performance status. On the other hand, The quality control of gamma camera and other systems were showed relatively good performance status. The results of precision of dose calibrator and thyroid uptake system was $\pm$1.4%(<$\pm$5%) and chi^2=29.7(>16.92), respectively. It showed that the sensitivity of CeraSPECT$^{TM}$ was higher in center slices compared with the edge slices. After correction of nonuniform sensitivities for patient data, it showed better results compare with prior to correction. System planar sensitivity of Varicam gamma camera was 4.39 CPM/MBq. The observed count rate at 20% loss was 102,407 counts/sec (head 1), 113,427 counts/sec (head 2), when input count rate was 81,926 counts/sec (head 1), 90,741 counts/sec (head 2). The spatial resolution without scatter medium were 8.16 mm of FWHM and 14.85 mm of FWTM. The spatial resolution with scatter medium were 8.87 mm of FWHM and 18.87 mm of FWTM. Conclusion: It is necessary to understand the importance of quality control and to perform quality control of nuclear medicine devices.vices.