Fabrication and Characterization of Al2O3-Siloxane Composite Thermal Pads for Thermal Interface Materials.

In this study, Al2O3-siloxane composite thermal pads were fabricated using a tape-casting technique, and the thermal conductivity effect of the Al2O3 nanoparticle powder synthesized using a flame fusion process on siloxane composite thermal pads was investigated. Furthermore, various case studies were implemented, wherein the synthesized Al2O3 nanoparticle powder was subjected to different surface treatments, including dehydration, decarbonization, and silylation, to obtain Al2O3-siloxane composite thermal pads with high thermal conductivity. The experimental results confirmed that the thermal conductivity of the Al2O3-siloxane composite pads improved when fabricated using surface-treated Al2O3 nanoparticle powder synthesized with an optimally spheroidized crystal structure compared to that produced using non-treated Al2O3 nanoparticle powder. Therefore, this study provides guidelines for fabricating Al2O3-siloxane composite thermal pads with high thermal conductivity in the field of thermal interface materials.

Associations of Metabolic Syndrome with Total Testosterone and Homocysteine Levels in Male Korean Workers.

BACKGROUND: Low testosterone is associated with metabolic syndrome (MetS), and homocysteine (Hcy) is elevated in individuals with MetS. We investigated the relationships of total testosterone (TT) and serum Hcy levels with MetS in male Korean workers. METHODS: We conducted a cross-sectional study including 8,606 male workers, aged 20 to 58 years, who underwent a physical examination in 2015. MetS was diagnosed based on the criteria of the 2009 harmonized definition, while the Korean standard for waist circumference (WC) was used. Participants' biochemical parameters, including TT and serum Hcy, were measured, and participants were divided into quartiles. Multiple logistic regression models were used to estimate the association of MetS and its individual components depending on TT and serum Hcy quartiles. RESULTS: The prevalence of MetS in the study population was 16%. TT was lower in participants with MetS than in those without MetS (P<0.001). By contrast, Hcy level was similar between groups (P=0.694). In multiple logistic regression analysis, the odds ratio for the lowest TT quartile was 1.29 (95% confidence interval, 1.06 to 1.57) after adjusting for potential confounders. Participants with lower TT were more likely to have high WC, hypertriglyceridemia, and low high density lipoprotein levels. Serum Hcy levels were not significantly associated with MetS. Of the five components of MetS, only WC was significantly associated with serum Hcy. CONCLUSION: In male Korean workers, TT may be an independent predictor of MetS, and serum Hcy levels could be a marker of abdominal obesity. However, future prospective studies are needed.

Discoid Medial Meniscus Tear, with a Literature Review of Treatments.

The present study reports our experience of treating four cases of symptomatic discoid medial meniscus, three of which were bilateral. We performed partial meniscectomy with a four-portal technique using a knife leaving a 6 mm peripheral margin after confirmation of magnetic resonance imaging findings. Clinical results were assessed at the end of 2-year follow-up using the Knee Injury and Osteoarthritis Outcome Score and a visual analogue scale. We obtained satisfactory clinical results without recurrence of the symptoms in all cases.

Trends and Age-Period-Cohort Effects on the Incidence and Mortality Rate of Cervical Cancer in Korea.

PURPOSE: This study was conducted to describe the trends and age-period-cohort effects on the incidence and mortality rate of cervical cancer in Korea. MATERIALS AND METHODS: The incidence and mortality rate of cervical cancer among ≥ 20-year-old women from 1993 to 2012 were obtained from the Korea Central Cancer Registry and the Korean Statistical Information Service. Age-standardized rates were calculated and Joinpoint regression was used to evaluate the trends in the incidence and mortality rate. Age-period-cohort analysis was performed to investigate the independent effects of age, period and cohort. RESULTS: The incidence of cervical cancer decreased from 32.8 per 100,000 in 1993 to 15.9 per 100,000 in 2012 (annual percent change [APC], -3.9%; 95% confidence interval [CI], -4.2% to -3.6%). The mortality rate decreased from 5.2 per 100,000 in 1993 to 2.1 per 100,000 in 2012 (APC, -4.8%; 95% CI, -5.1% to -4.4%); however, the incidence and mortality rates among young women (< 30 years old) increased. An age-period-cohort model of the incidence and mortality rate showed decreasing period effects between 1993 and 2008 and decreasing cohort effects between 1928 and 1973, while birth cohorts after 1973 exhibited slight increases in the incidence and mortality rate of cervical cancer. CONCLUSION: Recent decreases in the incidence and mortality rate of cervical cancer were due to decreases in the period and cohort effects, which reflect the implementation of a cancer screening program and changes in lifestyle. However, our findings also highlighted an increase in cohort effects on the incidence and mortality rate among young women born after 1973.

Decreases in Smoking-Related Cancer Mortality Rates Are Associated with Birth Cohort Effects in Korean Men.

Background: This study aimed to examine trends in smoking-related cancer mortality rates and to investigate the effect birth cohort on smoking-related cancer mortality in Korean men. Methods: The number of smoking-related cancer deaths and corresponding population numbers were obtained from Statistics Korea for the period 1984-2013. Joinpoint regression analysis was used to detect changes in trends in age-standardized mortality rates. Birth-cohort specific mortality rates were illustrated by 5 year age groups. Results: The age-standardized mortality rates for oropharyngeal decreased from 2003 to 2013 (annual percent change (APC): -3.1 (95% CI, -4.6 to -1.6)) and lung cancers decreased from 2002 to 2013 (APC -2.4 (95% CI -2.7 to -2.2)). The mortality rates for esophageal declined from 1994 to 2002 (APC -2.5 (95% CI -4.1 to -0.8)) and from 2002 to 2013 (APC -5.2 (95% CI -5.7 to -4.7)) and laryngeal cancer declined from 1995 to 2013 (average annual percent change (AAPC): -3.3 (95% CI -4.7 to -1.8)). By the age group, the trends for the smoking-related cancer mortality except for oropharyngeal cancer have changed earlier to decrease in the younger age group. The birth-cohort specific mortality rates and age-period-cohort analysis consistently showed that all birth cohorts born after 1930 showed reduced mortality of smoking-related cancers. Conclusions: In Korean men, smoking-related cancer mortality rates have decreased. Our findings also indicate that current decreases in smoking-related cancer mortality rates have mainly been due to a decrease in the birth cohort effect, which suggest that decrease in smoking rates.

Prediction of Cancer Incidence and Mortality in Korea, 2016.

PURPOSE: To estimate of Korea's current cancer burden, this study aimed to report on projected cancer incidence and mortality rates for the year 2016. MATERIALS AND METHODS: Cancer incidence data from 1999 to 2013 were obtained from the Korea National Cancer Incidence Database, and cancer mortality data from 1993 to 2014 were acquired from Statistics Korea. Cancer incidence in 2016 was projected by fitting a linear regression model to observed age-specific cancer incidence rates against observed years, then multiplying the projected age-specific rates by the age-specific population. The Joinpoint regression model was used to determine at which year the linear trend changed significantly. RESULTS: A total of 254,962 new cancer cases and 75,172 cancer deaths are expected to occur in Korea in 2016. The five leading primary cancer incident sites in 2016 were estimated colorectal, stomach, lung, liver and thyroid cancer in men; thyroid, breast, colorectal, stomach, and lung cancer in women. CONCLUSION: Currently cancer is one of the foremost public health concerns in Korea. Although cancer rates are anticipated to decrease the nation's cancer burden will continue to increase as the population ages.

Cancer Statistics in Korea: Incidence, Mortality, Survival, and Prevalence in 2013.

PURPOSE: This study described the 2013 nationwide cancer statistics in Korea, including cancer incidence, survival, prevalence, and mortality. MATERIALS AND METHODS: Cancer incidence data from 1999-2013 were obtained from Korea National Cancer Incidence Database and followed until December 31, 2014. Mortality data from 1983-2013 were obtained from Statistics Korea. The prevalence was defined as the number of cancer patients alive on January 1, 2014 among all cancer patients diagnosed since 1999. Crude, and age-standardized and 5-year relative survival rates were also calculated. RESULTS: In 2013, a total of 225,343 and 75,334 Koreans were newly diagnosed and died from cancer, respectively. The age-standardized rates for cancer incidence and mortality in 2013 were 290.5 and 87.9 per 100,000, respectively. The age-standardized cancer incidence rate increased 3.1% annually between 1999 and 2013. However, the overall cancer incidence rates have decreased slightly in recent years (2011 to 2013). The age-standardized rate for all-cancer mortality has decreased 2.7% annually since 2002. Overall, the 5-year relative survival rate for people diagnosed with cancer between 2009 and 2013 was 69.4%, which represents an improved survival rate as compared with 41.2% for people diagnosed between 1993 and 1995. CONCLUSION: Age-standardized cancer incidence rates have decreased between 2011 and 2013; mortality rates have also declined since 2002, while 5-year survival rates have improved remarkably from 1993-1995 to 2009-2013 in Korea.

Alanine aminotransferase and gamma-glutamyl transferase have different dose-response relationships with risk of mortality by age.

BACKGROUND & AIMS: It remains unclear whether the respective dose-response relationships between serum alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT) levels and risk of mortality are consistent by age. METHODS: We used sampled cohort data from the National Health Insurance Corporation to conduct a retrospective cohort study. A total of 313 252 participants who received medical health check-ups from 2002 to 2008 were assessed for risk of death according to serum ALT and GGT levels over an average of 6 years. The hazard ratios (HRs) for mortality were analysed with Cox proportional hazard model. RESULTS: The crude mortality rate increased linearly with increasing serum ALT and GGT levels in adults aged <60 years. However, the all-cause mortality rate showed a J-shaped relationship with increasing serum ALT levels whereas all-cause mortality rate showed a linear relationship with increasing serum GGT levels in adults aged ≥60 years. The HR of death showed U-shaped relationships with increasing serum ALT levels in adults aged ≥60 years. On the contrary, the HR of death from any cause had a linear association with increasing serum GGT levels among all age groups. CONCLUSIONS: In this study, U-shaped relationship patterns were demonstrated between serum ALT levels and risk for all-cause mortality in adults aged ≥60 years while serum GGT levels showed a linear relationship with risk for all-cause death. Very low levels of serum ALT in elderly patients suggest that they are at high risk of mortality.

Serum uric acid level and the incidence of metabolic syndrome in middle-aged Korean men: a 5-year follow-up study.

OBJECTIVES: Elevated serum uric acid (UA) has been known to be associated with the prevalence of metabolic syndrome (MetS). However, no prospective studies have examined whether serum UA levels are actually associated with the development of MetS. We performed a prospective study to evaluate the longitudinal effects of baseline serum UA levels on the development of MetS. METHODS: A MetS-free cohort of 14 906 healthy Korean men, who participated in a medical check-up program in 2005, was followed until 2010. MetS was defined according to the Joint Interim Statement of the International Diabetes Federation Task Force on Epidemiology and Prevention. Cox proportional hazards models were performed. RESULTS: During 52 466.1 person-years of follow-up, 2428 incident cases of MetS developed between 2006 and 2010. After adjusting for multiple covariates, the hazard ratios (95% confidence intervals) for incident MetS for the second, the third, and the fourth quartile to the first quartile of serum UA levels were 1.09 (0.92-1.29), 1.22 (1.04-1.44), and 1.48 (1.26-1.73), respectively (p for trend <0.001). These associations were also significant in the clinically relevant subgroup analyses. CONCLUSIONS: Elevated serum UA levels were independently associated with future development of MetS in Korean men during the 5-year follow-up period.

Decursin attenuates kainic acid-induced seizures in mice.

Epilepsy is a neurological disorder with recurrent unprovoked seizures as the main symptom. Of the coumarin derivatives in Angelica gigas, decursin, a major coumarin component, was reported to exhibit significant protective activity against glutamate-induced neurotoxicity when added to primary cultures of rat cortical cells. This study served to investigate the effects of decursin on a kainic acid (KA)-induced status epilepticus model. Thirty minutes after intraperitoneal injections of decursin (20 mg/kg) in male 7-week-old C57BL/6 mice, the animals were treated with KA (30 mg/kg, intraperitoneally) and then examined for behavioral seizure score, electroencephalogram, seizure-related expressed protein levels, neuronal cell loss, neurodegeneration, and astrogliosis. KA injections significantly enhanced neurodegenerative conditions but treatment with decursin 30 min before KA injection reduced the detrimental effects of KA in mice. The decursin-treated KA-injected group showed significantly decreased behavioral seizure activity and remarkably attenuated intense and high-frequency seizure discharges in the parietal cortex for 2 h compared with the group treated only with KA. Furthermore, in-vivo results indicated that decursin strongly inhibits selective neuronal death, astrogliosis, and oxidative stress induced by KA administration. Therefore decursin is able to attenuate KA-induced seizures and could have potential as an antiepileptic drug.

Clinical significance of non-alcoholic fatty liver disease as a risk factor for prehypertension.

Previous epidemiologic studies have shown the clinical association between non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). However, there is only limited information about the effect of NAFLD on the development of hypertension. Accordingly, we investigated the clinical association between NAFLD and prehypertension. A prospective cohort study was conducted on the 11,350 Korean men without prehypertension for 5 yr. The incidences of prehypertension were evaluated, and Cox proportional hazard model was used to measure the hazard ratios (HRs) for the development of prehypertension according to the degree of NAFLD (normal, mild, moderate to severe). The incidence of prehypertension increased according to NAFLD states (normal: 55.5%, mild: 63.7%, moderate to severe: 70.3%, P<0.001). Even after adjusting for multiple covariates, the HRs (95% confidence interval) for prehypertension were higher in the mild group (1.18; 1.07-1.31) and moderate to severe group (1.62; 1.21-2.17), compared to normal group, respectively (P for trend <0.001). The development of prehypertension is more potentially associated with the more progressive NAFLD than normal and milder state. These findings suggest the clinical significance of NAFLD as one of risk factors for prehypertension.

Blood cadmium levels are associated with a decline in lung function in males.

BACKGROUND: Cadmium exposure was found to cause a decline in lung function among the general population, but these findings were limited to smokers and gender differences were not explored. OBJECTIVES: To examine the relationship between cadmium and chronic obstructive pulmonary disease (COPD) according to gender and smoking status in Korea. METHODS: Cross-sectional data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011 were analyzed. COPD was defined by a pre-bronchodilator forced expiratory volume in 1s divided by forced vital capacity of <0.70. A logistic regression model was used to elucidate the association between blood cadmium levels and COPD according to gender and smoking status. RESULTS: Among 3861 eligible participants, 3622 were included in the analysis. The prevalence of COPD demonstrated an increasing trend in males (P for trend<0.001), but not in females (P for trend=0.67). After adjusting for covariates, a higher blood cadmium level, but within the normal range, was associated with COPD in males, including those who had never-smoked (P for trend <0.001 and P for trend=0.008). However, a higher blood cadmium level was not significantly associated with COPD in females, including those who had never smoked (P for trend=0.39 and P for trend=0.43). CONCLUSIONS: A higher blood cadmium level, within the normal range, was associated with COPD in males, including those who had never smoked. However, there was no significant association between blood cadmium levels and COPD in females.

Modified rheokinetic technique to enhance the understanding of microcapsule-based self-healing polymers.

A modified rheokinetic technique was developed to monitor the polymerization of healing monomers in a microcapsule-based, self-healing mimicking environment. Using this modified technique, monomers active toward ring-opening metathesis polymerization (ROMP) were either identified or disregarded as candidates for incorporation in self-healing polymers. The effect of initiator loading on the quality and speed of healing was also studied. It was observed that self-healing polymers have upper and lower temperature limits between which the healing mechanism performs at optimal levels. Also, a study of the quality of healing cracks of different thicknesses was performed, and it was discovered that above a critical crack thickness value, the quality of self-healing diminishes substantially; reasons for this phenomenon are discussed in detail.

Change of properties during storage of a UDMA/TEGDMA dental resin.

The aim of this study was to evaluate the changes in viscoelastic properties of a UDMA-based dental resin as a function of time after initial light exposure. Specimens of a UDMA/TEGDMA (70:30 wt%) resin were irradiated by a visible-light-curing unit. Immediately after the irradiation, the light-cured specimen was stored in the dark for different times from 1 to 120 h at 37 degrees C, and characterized by means of DMA, DSC, and FTIR spectroscopy. The irradiated specimen exhibited a bimodal shape in the form of two rapid declines in log E' corresponding to glass transition with a plateau between the two declines. Two distinct peaks were seen in tan delta versus temperature. The thermal reaction of the incompletely cured sample with residual groups trapped by the fast reaction during irradiation is responsible for the plateau. After storage, significant changes were observed in dynamic mechanical parameters, DSC exotherm, and degree of conversion. Storage modulus continued to increase during the 4 h of storage and leveled off thereafter. Peak heights of tan delta versus temperature were also influenced by storage. Degree of conversion increased from 75 +/- 2% immediately after irradiation to 87 +/- 3% after 120 h storage. The changes of the properties of this dental resin system when stored at 37 degrees C after irradiation are clinically important in terms of stability, durability, and performance after initial polymerization.

Synthesis of chitooligosaccharide derivative with quaternary ammonium group and its antimicrobial activity against Streptococcus mutans.

A derivative of chitooligosaccharide (COS) with quaternary ammonium functionality was synthesized and characterized by means of FT-IR and NMR spectroscopy. Its amtimicrobial activity was evaluated against Streptococcus mutans, which is a principal etiological agent of dental caries in humans. Introduction of quaternary ammonium group to COS has been easily accomplished by coupling of glycidyl trimethylammonium chloride (GTMAC) to COS in aqueous solution without an additional catalyst. The degree of substitution (%), as determined by (1)H NMR, of GTMAC to the COS increased up to 116% at 70 degrees C for 24h. The resulting COS-GTMAC exhibited the growth inhibition of above 80% against S. mutans after 5h, whereas the COS showed the growth inhibition of about 10%. It was found that antimicrobial activity of the COS could be considerably enhanced by the introduction of quaternary ammonium functionality.