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We fabricated boron carbide-silicon carbide (B4C–SiC) composites by hot-press sintering without additives and evaluated the crystal phase, relative density, microstructure, and mechanical properties of the sintered body. When B4C and SiC were uniformly dispersed in the composite, crystal growth was inhibited, and a sintered body with a fine and uniform microstructure, with improved mechanical properties, was fabricated. The relative density of B4C–SiC composites sintered at temperatures lower than 2000 °C and 40 MPa of pressure exceeded 99.8%, and the bending strength and Vickers hardness at B4C 50 wt% were 645 MPa and 30.6 GPa, respectively.

Sexually transmitted diseases refer to clinical syndromes and infections that are acquired and transmitted through sexual activity. Worldwide, more than 340 million cases of sexually transmitted disease occur each year, placing a great burden on individuals as well as communities and countries. The proportion of sexually transmitted diseases (STDs) in Mongolia is relatively high due to their inadequate treatment technologies, religious or local customs, and regional differences. It is rather difficult to grasp the exact number of patients as these diseases are considered ones that should not be disclosed to others. Therefore, this study aims to accurately identify sexually transmitted diseases in Mongolia and reduce infection through an analytic approach of big data virtualization propagation.

Polypropylene self-reinforced composites (PP-SRCs) are advantageous in terms of recycling, impact resistance, and price; however, a deeper understanding of their mechanical properties is required to expand their commercialization. Here, an in-depth study was conducted to understand the effect of changing PP-tape as a function of the draw ratio on the mechanical properties of PP-SRC. As the draw ratio increased, PP-tape showed higher orientation and thus significantly improved the tensile strength and Young's modulus. The tensile properties of PP-SRC showed the same trend; this was successfully predicted by employing the rule of mixtures as they were dominated by the reinforcing effect of PP-tape. Meanwhile, the impact resistance of PP-SRC improved with increasing draw ratio, but the T-peel adhesion deteriorated. This occurred because the failure mode at higher draw ratios transitioned from tape fracture to delamination, resulting in enhanced energy absorption ability, and the decrease in polymer chain mobility hindered interfacial inter-diffusion.

Self-reinforced composites (SRCs) are easy to recycle because the matrix and reinforcement are composed of the same material. However, the narrow processing window makes it difficult to optimize the relationship between the internal structure and the mechanical properties. In this study, we adopted a strategy to control the melting temperature and flowability of the matrix to expand the processing window of a polypropylene (PP)-based SRC. To experiment with this strategy, 1500% drawn PP fiber was used as the reinforcement, while a PP/low-density polyethylene (LDPE) blend, PP/ethylene copolymer, or PP/ethylene/butene terpolymer were adopted as the matrix. The tensile strength of the PP-based SRC prepared by applying the copolymer matrix under optimized processing conditions was improved by 22.3%, as compared to that of the SRC prepared using the raw PP matrix. As a result, the design rule used to obtain optimum processing conditions for SRC production with outstanding mechanical properties was proposed.

Schizophrenia is a debilitating mental disorder with a high heritability rate. Located on chromosome 1p31.3, the human cAMP-specific 3',5'-cyclic phosphodiesterase 4B (PDE4B) gene has been considered as an important candidate gene for the risk of schizophrenia. Several genetic association studies reported the association between PDE4B polymorphisms and the risk of schizophrenia in Caucasian, African American, Indian, and Japanese populations. The aim of this study is to examine the association of PDE4B variations with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. A case-control association analysis was carried out by comparing the genotype distribution of eight PDE4B polymorphisms between 457 schizophrenia patients and 386 normal healthy subjects. Differences in the frequency distribution of PDE4B single nucleotide polymorphisms (SNPs) and haplotypes were analyzed by logistic regression analyses controlling for age as a covariate. Statistical analyses revealed nominal significant associations of rs1040716, rs472952, rs1321177, and rs2144719 with the risk of schizophrenia (p = 0.02~0.05). The rs11208756 polymorphism showed a nominal significant association with SPEM abnormality (p = 0.05). In a meta-analysis with Japanese and Korean populations, three SNPs (rs472952, rs1040716, and rs2180335) revealed significant associations with schizophrenia (meta-p value = 0.0038~0.019). Our results support previously reported association of PDE4B variations with schizophrenia in other populations. The findings in this study add a new evidence for the involvement of PDE4B gene in schizophrenia etiology.

5,6 Assistant Manager, Technical Research Center, Hyundai Steel, Chungchun-do, Korea Abstract: In recent years, the construction of high-rise buildings are promoted. According to these, there are many needs about new technologies to strengthen the building performance and high-strength steel is regarded as one of these for promoting building performance. In Korea, high-strength steels which stress are over 600MPa are on market and in aborad, super high-strength steels over 1000MPa are developing and they expected to promote the building performance. But there are still doubts about applying high-strength steel members because of size effect and worry of brittle fracture. In this reports, we propose results of performance and analysis tests for use with general steel. We propose the characteristic of high-strength steels first and next the results of performance test to show they satisfy the performance that designers expect. And last, we compare the results of test and analysis for acquire the alanysis reliability in non-linear analysis with high-strength steels.

견관절수술에서관절경적시술이증가되면서, 이두근장두의손상에대한진단이같이증가하고있다. 이두근장두의건염에서시작하여서부분파열을거쳐서완전파열로진행되는경과를거치게된다. 이학적검사나영상검사만으로는이러한이두근장두의문제의유무및상태를수술전에확진하기가어렵다. 이두건의50%이상손상된경우에건절단술혹은건고정술을시행할수있다. 그러나환자개개인의연령,동반손상의정도에따라서그적응및술식의선택은술자의판단에따라서달라질수있다. 건고정술을시행하는경우에도다양한술식및고정부위가보고되고있다. 본종설은이러한다양한종류의이두근건고정술의결과를비교하고자하는것이다. 또한적절한고정강도에대하여, 현재문헌보고된생역학적실험의결과가임상적인결과와일치하는가에대한질문에대한답을찾고자하였다.건고정술의분류이두근건고정술의결과에대한문헌보고를단순히

OBJECTIVE To evaluate respiratory muscle strength in healthy Korean children in order to establish the criteria for normal reference values for future applications. In contrast with the other parameters for testing pulmonary function, normal values for respiratory muscle strength in healthy Korean children have not been assessed to date. METHODS We conducted a complete survey of 263 students at Sinmyung Elementary School in Yangsan, Gyeongsangnam-do, and measured their height and body weight, performed pulmonary function tests, and evaluated maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) as measures of respiratory muscle strength. We excluded the subjects with respiratory or cardiovascular diseases that could affect the results. The subjects were children aged 8-12 years, and they consisted of 124 boys and 139 girls. RESULTS The MIP and MEP values (mean±standard deviation) for the entire subject group were 48.46±18.1 cmH2O and 47.95±16 cmH2O, respectively. Boys showed higher mean values for MIP and MEP in every age group. Korean children showed lower mean values for MIP and MEP compared to those in previous studies conducted in other countries (Brazil and USA). CONCLUSION Our results showed that boys generally have greater respiratory muscle strength than girls. We found a significant difference between the results of our study and those of previous studies from other countries. We speculate that this may be attributed to differences in ethnicity, nutrition, or daily activities.

In this study, normal and dichlorodicyanuric acid (DCCA)-treated wool slivers and yarns were immersed in a formic acid solution at elevated temperatures as a pre-treatment in order to accelerate the scale removal and fiber splitting of wool by ultrasonication and the effect of pre-treatment on the morphology and fiber splitting of wools was investigated. As the formic acid concentration, the treatment temperature, and the treatment time increased, the scale removal on wool fiber increased, however, the occurrence of felting and yellowing regarding wool fiber also increased indicating that the treatment with 50% formic acid at for 3 hours was the optimum pre-treatment condition for wool fiber. The SEM observation revealed that the formic acid treatment on wool at followed by ultrasonication was the effective tool in order to produce split fibers for both normal and DCCA-treated wool. The comparative study of sliver and yarn revealed that ultrasonication could lead to the fiber splitting of wool sliver whereas it could not result in that of wool yarn. On the other hand, formic acid treatment at resulted in fiber splitting for both wool sliver and yarn.

The characteristics of high heat input (342kJ/cm) EG (Electro Gas Arc) welded joint of EH36-TM steel has been investigated. The weld metal microstructure consisted of fine acicular ferrite (AF), a little volume of polygonal ferrite (PF) and grain boundary ferrite (GBF). Charpy impact test results of the weld metal and heat affected zone (HAZ) met the requirement of classification rule (Min. 34J at -20 ℃). In order to evaluate the relationship between the impact toughness property and the grain size of HAZ, the austenite grain size of HAZ was measured. The prior austenite grain size in Fusion line (F.L+0.1 mm) was about 350 ㎛. The grain size in F.L+1.5 mm was measured to be less than 30 ㎛ and this region was identified as being included in FGHAZ(Fine Grain HAZ). It is seen that as the austenite grain size decreases, the size of GBF, FSP (Ferrite Side Plate) become smaller and the impact toughness of HAZ increases. Therefore, the CGHAZ was considered to be area up to 1.3mm away from the fusion line. Results of TEM replica analysis for a welded joint implied that very small size (0.8~1.2㎛) oxygen inclusions played a role of forming fine acicular ferrite in the weld metal. A large amount of (Ti, Mn, Al)xOy oxygen inclusions dispersed, and oxides density was measured to be 4,600-5,300 (ea/mm2). During the welding thermal cycle, the area near a fusion line was reheated to temperature exceeding 1400℃. However, the nitrides and carbides were not completely dissolved near the fusion line because of rapid heating and cooling rate. Instead, they might grow during the cooling process. TiC precipitates of about 50 ~100nm size dispersed near the fusion line.Key Words : EH36-TM steel, High heat input, EGW, Grain boundary ferrite, Acicular ferrite, Polygonal ferrite, Prior Austenite Grain Size, Oxygen inclusions

Aramid fibers have been widely used as the reinforcement for composites due to their high modulus and strength. Nowadays the safety measures is required to improve the personal protection. The dyeing of aramid fibers is considered to be very difficult and their dyeing mechanism is not well illucidated. Therefore, this study is to establish the dyeing & printing technology for aramid fibers. The effects of swelling agent and neutral salt in the dye bath on the obtained colors were studied. Also dyeing method of aramid fibers depending on dyeing temperature and dye concentration were established. Color fastness of the dyed aramid fabric with cationic dyes were acceptable excluding light fastness.

In this study, the possibility of the practical development of highly sensitive clothing textiles using fibrillated wool fibers were considered by determining the dyeability, the physical and mechanical properties of fibrillated wool fibers treated under strong acid and high temperature ultrasonic wave irradation and they were compared with those of untreated wool fibers. The color strengths of the dyed fibrillated wool fabrics increased by the acid metal complex dyes contrary to the untreated wool fabrics, and color fastness properties to rubbing, light, and dry cleaning were excellent, similar to those of the untreated wool fabrics. The tensile strengths of fibrillated wool fabrics were also kept after the dyeing. Moreover, the Numeri, Fukurami, and THV of the fibrillated wool fabrics were better than those of the untreated wool fabrics.

The gasket materials of for the lithium ion battery requires chemical resistance to electrolyte, electrical insulating, compression set, anti-contamination and low temperature property. To check the special characteristics of fillers which are applied to rubber for gasket, compound of EPDM, NBR and FKM (fluoro elastomer) were made by adjusting weights of carbon black and silica additive. Using these compounds, we had done tests of long-term stability against electrolyte, compression set and low-temperature property with considering operating condition of the lithium ion battery. From this test, we investigated the physical and chemical characteristics of rubber with using of carbon black and silica additive in each.

This study surveys the optimum processing conditions of ATY for PET braiding for automotive hoses. For this purpose, high tenacity and low shrinkable PET filaments with three types of deniers are prepared. Twenty seven ATY specimens are manufactured with variation of feed speed and overfeed on the air jet texturing machine. The physical properties of various yam according to the ATY processing conditions are measured and analysed for deciding the optimum ATY processing condition. Two kinds of ATY filaments made under the optimum air texturing conditions are processed with variation of tpm, heat setting temperature and heat setting time on the 2-for-l twister and setting chamber, respectively. The optimum twisting and heat setting conditions are decided through analysis of the yam physical properties. Finally, the braiding fabric specimens are manufactured using conventional filament and newly developed filament made under optimum twisting and heat setting conditions. The bursting strengths of these braiding specimens are compared and discussed between two types of specimens.

Background/Aims: There has been no report concerning the predictive capability of each scoring system in determining the development of complications of liver cirrhosis such as variceal bleeding and/or hepatic encephalopathy. Methods: We retrospectively studied 128 patients with liver cirrhosis [92 males; mean (standard deviation) 54.2 (11.2) years] admitted to our institution from March 2004 to April 2006. Seventy-three patients (57.0%, group 1) were admitted because of complications of cirrhosis and 55 patients (43.0%, group 2) were admitted for causes unrelated to complications of cirrhosis. We calculated values for model for end-stage liver disease (MELD), MELD-sodium (MELD-Na) and Child–Turcotte–Pugh (CTP) scores on admission and at 3 and 6 months before admission. Each delta score was defined as the difference in the scores of 3 and 6 months before admission. Results: The relative risk for complications in the patients with ΔMELD/3 months ≥1.35, ΔMELD-Na/3 months ≥1.35 and ΔCTP/3 months ≥1 was 2.05 [95% confidence intervals (CI) 1.47–2.85, P

This paper suggests a physical activity assessment method based on quaternion. To reduce user inconvenience, we measured the activity using a mobile device which is not put on fixed position. Recognized results were verified with various machine learning algorithms, such as neural network (multilayer perceptron), decision tree (J48), SVM (support vector machine) and naive bayes classifier. All algorithms have shown over 97% accuracy including decision tree (J48), which recognized the activity with 98.35% accuracy. As a result, physical activity assessment method based on rotated acceleration using quaternion can classify sedentary behavior with more accuracy without considering devices' position and orientation.

This study was carried out to investigate the effect of heating rate on dissolution and solidification behavior during transient liquid phase diffusion bonding of Ni-based superalloy GTD-111. The heating rate was varied by 0.1K/sec, 1K/sec, 10K/sec to the bonding temperatures 1373K and 1423K in vacuum. When the heating rate was slower and the bonding temperature was higher, the completion time of dissolution after reaching bonding temperature decreased. When the heating rate was very slow, the solidification proceeded before reaching bonding temperature and the time required for the completion of isothermal solidification was shorter. However, when the total time required for completion of solidification from the beginning of heating was considered, heating at 0.1K/sec was nearly the same as heating at 10K/sec.

This study examined the association of the reticulon 4 receptor (RTN4R) gene with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Although we failed to provide convincing evidence that RTN4R is associated with schizophrenia development and SPEM impairment, our findings may be useful for further genetic studies.

Schizophrenia is a serious and disabling mental disorder with a high heritability rate. The human neuregulin 1 (NRG1) on 8p12 has been implicated as a candidate gene for schizophrenia. However, controversial results of the associations of NRG1 polymorphisms with schizophrenia and related phenotypes have been reported. In this study, four NRG1 single nucleotide polymorphisms, three in the promoter region, and one nonsynonymous in coding region, were genotyped in a total of 825 subject including 435 schizophrenia cases and 390 normal controls of Korean ethnicity. Although logistic association analysis of NRG1 polymorphisms and haplotypes with schizophrenia showed a nominal association in rs4623364G > C (P = 0.04), the significance disappeared after corrections for multiple testing (corrected P > 0.05). Additional case/control and multiple regression analyses in schizophrenia patients using a method that measures the smooth pursuit eye movement (SPEM) function globally based on natural logarithmic values of the signal/noise ratio also showed no association between NRG1 variants and SPEM abnormality among patients with schizophrenia (P > 0.05). Despite the need for further replications in other cohorts, our findings provide additional supporting information that four variants in NRG1 investigated in this study may not be associated with schizophrenia and its related SPEM function in a Korean population.

Focally enhanced gastritis (FEG) has been suggested as a specific diagnostic marker for patients with Crohn's disease (CD). However, the usefulness of FEG for distinguishing CD from ulcerative colitis (UC) is uncertain and the incidence or prevalence of FEG for inflammatory bowel disease (IBD) patients in Korea has not been defined yet. In this study, we investigated the frequency of FEG and other gastric histological abnormalities in Korean patients with CD and UC.We evaluated 37 patients with known CD, 43 patients with UC and 41 non-IBD control group; all underwent upper gastrointestinal endoscopy followed by biopsy from the antrum and the body. The pathology of the gastric biopsy specimens and the presence of Helicobacter pylori (H. pylori) were evaluated. FEG was characterized by a focal perifoveolar or periglandular inflammatory cell infiltrates.H. pylori positive gastritis was found in 10 of 37 (27.0%) of CD patients, in 16 of 43 (37.2%) of UC patients, and in 22 of 41 (53.7%) of non-IBD control group (p=0.054). In H. pylori-negative patients, FEG was found in 8 of 27 patients (29.6%) of CD patients, 6 of 27 (22.2%) patients with UC, and 2 of 9 (10.5%) of non-IBD control group (p=0.324).In H. pylori-negative patients, there was no statistically significant difference in the occurrence of FEG among CD, UC and control groups in Korea.

Conflicting results have been reported whether patients with non-ulcer dyspepsia (NUD) respond differently to Helicobacter pylori (H. pylori) eradication treatment compared with patients with peptic ulcer diseases (PUD). The aim of this study was to evaluate any difference in H. pylori eradication rates between patients with NUD and PUD according to each proton pump inhibitor (PPI).From September, 2004 to April, 2007, we retrospectively reviewed 2,297 patients with NUD (1,050 patients) or PUD (1,247 patients) infected with H. pylori. All patients received a standard 1 week triple therapy comprising of one of the five PPIs (pantoprazole, esomeprazole, omeprazole, lansoprazole, rabeprazole), clarithromycin and amoxicillin. The follow-up H. pylori test was performed 4 weeks after the completion of therapy.There was no significant difference in the eradication rates between the two groups. In comparison of eradication rates according to PPI, omeprazole- based triple therapy group showed higher eradication rate than other groups in patients with NUD, but not in patients with PUD.This study failed to show any difference in H. pylori eradication rate between patients with NUD and PUD. There is no convincing evidence that the eradication rate may be affected by different PPI.

Antibiotic resistance and poor compliance are the main causes of Helicobacter pylori (H. pylori) eradication failure. Proton pump inhibitor (PPI)-based triple therapy is the most preferred regimen in clinical practice. However, a critical fall in the H. pylori eradication rate has been observed in the recent years. A novel 10 day-sequential therapy consists of five days of dual therapy followed by five days of triple therapy regimen has recently been described. We aimed to evaluate whether 10 day-sequential therapy eradicated H. pylori infection better than the PPI-based triple therapy in Korea.158 patients with proven H. pylori infection were randomized to receive either 10 day-sequential therapy (20 mg of omeprazole, 1.0 g of amoxicillin, each administered twice daily for the first 5 days, followed by 20 mg of omeprazole, 500 mg of clarithromycin, 500 mg of metronidazole, each administered twice daily for the remaining 5 days) or PPI-based triple therapy (20 mg of omeprazole, 1.0 g of amoxicillin, 500 mg of clarithromycin, each administered twice daily for 1 week). Outcome of eradication therapy was assessed 8 weeks after the cessation of treatment.Eradication rates of 10 day-sequential therapy and PPI-based triple therapy were 77.9% (60/77) and 71.6% (58/81) by intention to treat analysis, respectively (p=0.361). By per protocol analysis, eradication rates of 10 day-sequential therapy and triple therapy were 85.7% (60/70) and 76.6% (58/76), respectively (p=0.150). There were no significant differences in adverse event rates and treatment compliance between two groups.The 10 day-sequential therapy regimen failed to achieve significantly higher eradication rates than PPI-based triple therapy.

The DISC1 gene is considered to be a strong candidate gene for the development of schizophrenia. This study examines the association of DISC1 polymorphisms with schizophrenia in a Korean population. Although we fail to discover convincing evidence that DISC1 affects schizophrenia development, our findings may be useful for further genetic studies.

Purpose : To evaluate the efficacy of arthroscopic synovectomy through the direct posteriorposterior approach in pigmented villonodular synovitis (PVNS) of the knee. Materials and Methods : Between January 1997 and May 2004, twenty-one patients underwent an arthroscopic synovectomy for PVNS of knee. The mean follow-up period was 35 months. The arthroscopic and MRI findings revealed the localized form of PVNS in six patients and the diffuse form in fifteen patients. All patients underwent an arthroscopic examination and synovectomy through the direct posterior-posterior approach. The clinical results were evaluated by the range of motion, Lysholm knee score, and the knee pain score using the visual analogue scale (minimum 0-maximum 10). Results : Among the fifteen cases with the diffuse form, three cases (14%) recurred and had secondary arthroscopic total synovectomy. One cases recurred again. Therefore, radiation therapy was performed. The Lysholm knee score improved from 62.5 to 87.3, and the VAS score improved from 5.9 to 1.8. Three patients had a mild limitation in knee motion. However, the others had full range of motion of the knee at the last follow-up. Conclusion : Arthroscopic synovectomy through the direct posterior-posterior approach could be a useful method for the treatment of PVNS of the knee, and can be used as an effective therapeutic tool particularly in posteromedial or posterolateral lesions.

Purpose: To investigate the effect of lateral buttress on the fracture healing of Jensen type 4 intertrochanteric fracture of the femur treated by dynamic compression hip screw (DCS) in elderly patients, retrospectively. Materials and Methods: From March 1999 to February 2003, 54 patients, older than 65 years, of Jensen type 4 intertrochanteric fractures of the femur treated by DCS were included. The relationship between the structual integrity of lateral buttress measured by proximal-medial fragment angle (PMFA) and postoperative neck-shaft angle, penetrating length of lag screw, the sliding length and incidence of fixation loss were evaluated. Results: Among 38 patients of group II (PMFA above 50 degree), 6 cases (15.8%) including 4 cases of cutting out of lag screw from femoral head, 1 case of nonunion and 1 case of excessive extrusion of lag screw failed radiologically. But there was no fixation loss case in 16 cases of group I (PMFA 50 and below 50). The neck-shaft angle in last follow-up was 138.1 degree in group I and 132.1 in group II. The sliding length of lag screw was 7.0 mm in group I and 12. 5 mm in group II (p

Magnetic fields are widely considered as a method of treatment to increase the therapeutic effect when applied to acupoints. Hence, this study proposes a new method which creates significant stimulation of acupoints by using weak magnetic fields. We conducted this experiment in order to confirm the effect on the activation level of the autonomic nervous system by measuring pupil sizes in cases of stimulation by using manual acupuncture and electromagnetic acupuncture (EMA) at BL15. We selected 30 Hz of biphasic wave form with 570.1 Gauss. To confirm the biopotential by the magnetic flux density occurring in EMA that affected the activation of the autonomic nervous system, we observed the biopotential induced at the upper and the mid left and right trapezius. We observed a significant decrease in pupil size only in the EMA group (p