• Journal of Korean Neurosurgical Society
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• 제61권2호
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• pp.180-185
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• 2018

Objective : Many lumbosacral fixation techniques have been described to offer a more screw-bone purchase. The forward anatomical fixation parallel to the endplate is still the most preferred method. Literature revealed little knowledge regarding the mechanical stability of lumbosacral trans-endplate fixation compared to the traditional trans-pedicular screw fixation method. The aim of this study is to assess the pull-out strength of lumbosacral screws penetrating the end plate and comparing it to the conventional trans-pedicular screw insertion method. Methods : Eight lumbar and eight sacral vertebrae, with average age 69.4 years, Left pedicles of the 5th lumbar vertebrae were used for trans-endplate screw fixation, group 1A, right pedicles were used for anatomical trans-pedicular screw fixation, group 1B. In the sacral vertebrae, the right side S1 pedicles were used for trans-endplate fixation, group 2A, left side pedicles were used for anatomical trans-pedicular screw fixation, group 2B. The biomechanical tests were performed using the axial compression testing machine. All tests were applied using 2 mm/min traction speed. Results : The average pull-out strength values of groups 1A and 1B were $403.78{\pm}11.71N$ and $306.26{\pm}17.55N$, respectively. A statistical significance was detected with p=0.012. The average pull-out strength values of groups 2A and 2B were $388.73{\pm}17.03N$ and $299.84{\pm}17.52N$, respectively. A statistical significance was detected with p=0.012. Conclusion : The trans-endplate lumbosacral fixation method is a trustable fixation method with a stronger screw-bone purchase and offer a good alternative for surgeons specially in patients with osteoporosis.

• 한국환경보건학회지
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• 제43권4호
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• pp.267-272
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• 2017

Objectives: The purposes of the study were to analyze the temporal variation of carbon dioxide ($CO_2$) and particulate matter (PM) in daycare centers and evaluate the appropriateness of the official test method of one-time measurement. Methods: Indoor air quality in 46 daycare centers in the Seoul Metropolitan Area was measured as specified in the official test method of Indoor Air Quality Management law. In addition, indoor air quality in the 46 daycare centers was measured over 37 days using a real-time monitor (AirGuard K). Results: The daily means of $CO_2$ and PM in the 46 daycare centers were $1042.74{\pm}134.45ppm$ and $67.60{\pm}18.25{\mu}g/m^3$, respectively. Indoor air quality in the daycare centers showed significant temporal fluctuation. Measurements for single days were significantly different from the 37-day average exposure. Relative error of short term exposure decreased with an increase in the number of sampling days. The noncompliance rate for $CO_2$ using the official testing method was 2.17%, and none exceeded the $PM_{10}$ standard of $100{\mu}g/m^3$. With monitoring over 37 days, the daily noncompliance rate for $CO_2$ was 50.4% and the daily noncompliance rate for PM was 13.8%. Conclusions: When the official test method evaluates the indoor air at daycare centers one day per year, the results may not represent actual indoor air quality over a longer period of time. Real-time monitoring devices could be an alternative for managing indoor air quality.

• Communications for Statistical Applications and Methods
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• 제19권1호
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• pp.47-55
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• 2012

식품의약품안전청에서는 제제간의 생물학적 동등성의 입증이 실패했을 경우 추가시험을 허용하는 시험 기준을 2008년 7월부터 시행하고 있다. 생물학적 동등성 시험의 추가시험규정은 원시험에서의 동등성 평가가 불충분한 시험 예수 때문에 실패했을 때 별도의 재시험 시험계획서를 제출하지 않고 피험자수를 증가시켜 다시 시험하여 제제간의 동등성을 평가할 수 있는 근거를 마련한 점에 긍정적이다. 하지만 최근 추가시험의 규정에 따라 군당 12명 이상의 피험자를 사용했을 경우 오히려 추가시험의 일관성 검정 규정을 만족하지 못하여 추가시험이 실패되는 경우가 자주 발생하고 있어 추가시험규정에 대한 불만이 고조되고 있다. 본 연구에서는 이러한 상황이 발생되는 통계적 원인을 살펴보고 현 기준을 일본 규정처럼 조금 더 일반화하게 되면 추가시험을 더 폭넓게 사용할 수 있는 것을 제안하고자 한다.

• The Korean Journal of Pain
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• 제23권3호
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• pp.179-185
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• 2010

Background: Vincristine-induced peripheral neuropathy is a major dose limiting side effect and thus effective therapeutic strategy is required. In this study, we investigated the antinociceptive effect of memantine and morphine on a vincristine-induced peripheral neuropathy model in rats. Methods: Male Sprague-Dawley rats weighing 220-240 g were used in all experiments. Rats subsequently received daily intraperitoneal injections of either vincristine sulfate (0.1 ml/kg/day) or saline (0.1 ml/kg/day) over 12 days, immediately following behavioral testing. For assessment of mechanical allodynia, mechanical stimuli using von Frey filament was applied to the paw to measure withdrawal threshold. The effects of N-methyl-D-aspartate receptors antagonist (memantine; 2.5, 5, 10 mg/kg intraperitoneal), opioid agonist (morphine; 2.5, 5, 10 mg/kg intraperitoneal) and vehicle (saline) on vicristine-induced neuropathy were evaluated. Results: Mechanical allodynia developed over the course of ten daily injections of vincristine relative to groups receiving saline at the same time. Morphine abolished the reduction in paw withdrawal threshold compared to vehicle and produced dose-responsiveness. Only the highest dose of memantine (10 mg/kg) was able to increase paw withdrawal threshold compared to vehicle. Conclusions: Systemic morphine and memantine have an antinociceptive effect on the vincristine-induced peripheral neuropathy model in rats. These results suggest morphine and memantine may be an alternative approach for the treatment of vincristine-induced peripheral neuropathic pain.

• 대한조선학회논문집
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• 제54권1호
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• pp.43-48
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• 2017

In recent years, the demand for ships and offshore platforms that can navigate and operate through the Arctic Ocean has been rapidly increasing due to global warming and large reservoirs of oil and natural gas in the area. Winterization design is one of the key issues to consider in the robust structural safety design and building of ships that operate in the Arctic and Sub-Arctic regions. However, international regulations for winterization design in Arctic condition regulated that only those ships and offshore platforms with a Polar Class designation and/or an alternative standard. In order to cope with the rising demand for operating in the Arctic region, existing and new Arctic vessels with a Polar Class designation are lacking to cover for adequate winterization design with HSE philosophy. Existing ships and offshore platform was not designed based on reliable data based on numerical and experiment studies. There are only designed as a performance and functional purposes. It is very important to obtain of reliable data and provide of design guidance of the anti-icing structures by taking the effects of low temperature into consideration. Therefore, the main objective of this paper reconsiders anti-icing design of aluminum helideck using the heating cable. To evaluate of reliable data and recommend of anti-icing design method, various types of analysis and methods can be applied in general. In the present study, finite element method carried out the thermal analysis with cold chamber testing for performance and capacity of heating cables.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권1호
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• pp.53-60
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• 2002

Neurosensory dysfunction of the injured inferior alveolarnerve(IAN) is a common and distrssing consequence of traumatic or iatrogenic injury. Conventional neurosensory testing has been used to detect and monitor sensory impairments of the injured IAN. However, these tests had low reliability and are not qualitative at best because they are based on solely on the patient's subjective assesment of symptoms. Consequently, there is need for more reliable, sensitive, and objective test measures to document and to monitor sensory dysfunction of the trigeminal nerve. This study was to investigate DITI's (digital infrared thermographic imaging) potential as a diagnostic alternative for evaluating of the nerve injures and sensory disturbance. Subjects were 30 patients who had been referred to Ewha Medical Center due to sensory disturbance of the lower lip and chin followed after unobserved inferior alveolar nerve injuries. The patients were examined by clinical neurosensory tests as SLTD (static light touch discrimination), MDD (moving direction discrimination), PPN (pin prick nociception) and DITI (digital infrared thermographic imaging). The correlation between clinical sensory dysfunction scores(Sum of SLTD, MDD, PPN, NP, Tinel sign) and DITI were tested by Spearman nonparametric rank correlation anaylsis & Kruskal-Wallis test, Wilcoxon 2-sample test. This study resulted in as follows; (1) The difference of thermal difference between normal side and affected side was as ${\Delta}-3.2{\pm}0.13$. (2) The DITI differences of the subjects presenting dysesthesia of the lip and chin were correlated significantly with the neurosensory dysfunction scores(r=0.419, p=0.021)and SLTD (r=0.429, p<0.05). (3) The MDD, PPN, NP, Tinel sign, duration, gender were not correlated with DITI(p> 0.05). Therefore, the DITI(digital infrared thermographic imaging) can be an option of the useful objective diagnostic methods to evaluate the injured inferior alveolar nerve and sensory dysfunction of trigerminal nerve.

• 대한치과교정학회지
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• 제48권2호
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• pp.107-112
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• 2018

Objective: The aim of this study was to examine the properties of fiber-reinforced composite and stainless steel twisted retainers for orthodontic retention. Methods: Three different span lengths (5.0, 8.0, and 14.0 mm) of fiber-reinforced composite were investigated. The three fiber-reinforced composite retainer groups were subdivided according to the storage condition (dry and wet), resulting in a total of six groups. Each stainless steel and fiber-reinforced composite group was comprised of six specimens. The three-point bending flexural test was conducted using a universal testing machine. ANOVA was used to assess differences in the maximum load and maximum stress according to the span length, material, and storage condition. Post-hoc comparisons were performed if necessary. Results: The maximum stress and maximum load were significantly (p < 0.001) associated with the span length, material, and storage condition. The significant interaction between the material and span length (p < 0.001) indicated the differential effects of the material for each span length on the maximum stress and maximum load, with the difference between materials being the highest for the maximum span length. Conclusions: Our findings suggest that fiber-reinforced composite retainers may be an effective alternative for orthodontic retention in patients with esthetic concerns or allergy to conventional stainless steel wires.

• Advances in Traditional Medicine
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• 제7권1호
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• pp.51-64
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• 2007

Mucus is an aqueous gel complex with a constitution of about 95% water, high molecular weight glycoprotein (mucin), lipid, salts etc. Mucus appears to represent a significant barrier to the absorption of some compounds. Natural mucoadhesive agent was isolated and purified from the aqueous extract of the seeds of prosopis pallida (PP). Formulated tablet with the isolated material by wet granulation method. Some natural edible substances are in consideration for candidates as mucoadhesive agents to claim more effective controlled drug delivery as an alternative to the currently used synthetic mucoadhesive polymers. Subjected the materials obtained from natural source i.e. PP and standard synthetic substance, sodium carboxymethyl cellulose for evaluation of mucoadhesive property by various in vitro and in vivo methods. Through standard dissolution test and a model developed with rabbit, evaluated in vitro controlled release and bioadhesive property of theophylline formulation. Mucoadhesive agent obtained from PP showed good mucoadhesive potential in the demonstrated in vitro and in viνo models. The results suggest that the mucoadhesive agent showed controlled release properties by their application, substantially. In order to assess the gastrointestinal transit time in vivo, a radio opaque X-ray study performed in healthy rabbit testing the same controlled release formulation with and without bioadhesive polymer. Plasma levels of theophylline determined by the HPLC method and those allowed correlations to the in vitro mucoadhesive study results. Better correlation found between the results in different models. PP may acts as a better natural mucoadhesive agent in the extended drug delivery system.

• The Journal of Advanced Prosthodontics
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• 제2권4호
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• pp.134-141
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• 2010

PURPOSE. The objective of this study was to evaluate fracture strength of collarless metal-ceramic FPDs according to their metal coping designs. MATERIALS AND METHODS. Four different facial margin design groups were investigated. Group A was a coping with a thin facial metal collar, group B was a collarless coping with its facial metal to the shoulder, group C was a collarless coping with its facial metal 1 mm short of the shoulder, and group D was a collarless coping with its facial metal 2 mm short of the shoulder. Fifteen 3-unit collarless metal-ceramic FPDs were fabricated in each group. Finished FPDs were cemented to PBT (Polybutylene terephthalate) dies with resin cement. The fracture strength test was carried out using universal testing machine (Instron 4465, Instron Co., Norwood MA, USA) at a cross head speed of 0.5 mm/min. Aluminum foil folded to about 1 mm of thickness was inserted between the plunger tip and the incisal edge of the pontic. Vertical load was applied until catastrophic porcelain fracture occurred. RESULTS. The greater the bulk of unsupported facial shoulder porcelain was, the lower the fracture strength became. However, there were no significant differences between experimental groups (P > .05). CONCLUSION. All groups of collarless metal-ceramic FPDs had higher fracture strength than maximum incisive biting force. Modified collarless metal-ceramic FPD can be an alternative to all-ceramic FPDs in clinical situations.

• Toxicological Research
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• 제26권1호
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• pp.9-14
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• 2010

The evaluation of eye and skin irritation potential is essential to ensuring the safety of human in contact with a wide variety of substances. Despite this importance of irritation test, little is known with respect to the irritation potency of lomefloxacin, a fluoroquinolone antibiotic, which has been known to cause phototoxicity with an abnormal reaction of the skin. Thus, to investigate the tendency of lomefloxacin to cause eye and skin irritation, we carried out in vitro eye irritation test using Balb/c 3T3, and in vitro skin irritation test using $KeraSkin^{TM}$ human skin model system. 3T3 neutral red uptake assay has been proposed as a potential replacement alternative for the Draize Eye irritation test. In this study, the $IC_{50}$ value obtained for lomefloxacin was 375 ${\mu}g$. According to the classification model used for determining in vitro categories, lomefloxacin was classified as moderately irritant. For evaluation of skin irritation, engineered epidermal equivalents ($KeraSkin^{TM}$) were subjected to 10 and 25 mg of lomefloxacin for 15 minutes. Tissue damage was assessed by tissue viability evaluation, and by the release of a pro-inflammatory mediator, interleukin- 1${\alpha}$. Lomefloxacin increased the interleukin-1${\alpha}$ release after 15 minutes of exposure and 42 hours of post incubation, although no decrease in viability was observed. Therefore, lomefloxacin is considered to be moderately irritant to skin and eye.