Method for improving the speed and pattern quality of a DMD maskless lithography system using a pulse exposure method.

Maskless lithography based on a digital micromirror device (DMD) has the advantages of high process flexibility and a low production cost. However, due to the trade-off relationship between the pixel size and exposure area, it is challenging to achieve high resolutions and high patterning speeds at the same time, which hinders the wider application of this technology in micro- and nano-fabrication processes. In addition, micromirrors in DMDs create pixelated edges that limit the pattern quality. In this paper, we propose a novel DMD maskless lithography method to improve the pattern quality during high-speed continuous patterning by means of pulse exposure and oblique scanning processes. A unique criterion, the pixel occupancy, was devised to determine the parameters related to the pulse exposure and oblique scanning optimally. We also studied how the duty cycle of the pulse exposure affects the pattern quality. As a result, we were able to increase the scanning speed up to the speed limit considering the damage threshold of the DMD and improve the pattern quality by resolving the pixelation problem. We anticipate that this method can be used in various microfabrication fields with short product life cycles or in those that require custom designs, such as the manufacturing of PCBs, MEMS devices, and micro-optics devices, among others.

Parathyroid Hormone Levels Are Independently Associated with eGFR and Albuminuria: The Dong-gu Study.

Increased parathyroid hormone (PTH) was associated with cardiovascular mortality and morbidity in CKD patients. Our aim was to investigate the associations among estimated glomerular filtration rate (eGFR), albumin/creatinine ratio (ACR) and PTH independent of 25-hydroxyvitamin D (25(OH)D). This study included 9,162 individuals who completed the baseline survey of the Dong-gu Study, which was conducted in Korea from 2007 to 2010. The eGFR, ACR, PTH and 25(OH)D were measured in participants who met the detailed inclusion criteria. After being adjusting for covariates (sex, age, waist circumference, smoking, alcohol intake, physical activity, hypertension medications, diabetes medication, total cholesterol, triglyceride, HDL cholesterol) and log-ACR, the PTH value stratified by 25(OH)D level significantly decreased with increasing eGFR levels in each 25(OH)D stratum. Moreover, after adjustment for the same covariates and log-eGFR, the PTH value stratified by 25(OH)D level significantly increased with increasing ACR levels in each 25(OH)D stratum. In conclusion, the PTH values significantly decreased with increasing eGFR levels and increased with increasing ACR levels independently of 25(OH)D in an adult Korean population ≥50 y of age.

Association of serum vitamin D and parathyroid hormone with subclinical atherosclerotic phenotypes: The Dong-gu Study.

BACKGROUND: Although previous studies reported an association between serum vitamin D and parathyroid hormone (PTH) with carotid atherosclerosis or arterial stiffness, these were inconsistent. We examined the independent association between serum vitamin D and PTH with multiple subclinical markers of atherosclerosis. METHODS: A total of 8,217 subjects who participated in the Dong-gu Study in Korea were included in the final analysis. The carotid artery structure, including intima-media thickness (IMT), plaques, and luminal diameter, was evaluated using a high-resolution B-mode ultrasound. The brachial-ankle pulse wave velocity (baPWV) was determined using an automatic waveform analysis device, and the mean of the left and right baPWV was used. RESULTS: The PTH concentration was positively associated with carotid luminal diameter and baPWV, but not with carotid IMT and plaques. The mean carotid luminal diameter of individuals with PTH levels in the second, third, and fourth quartiles was significantly larger compared with those in the first quartile (P-trend < 0.01). The mean baPWV of individuals with PTH levels in the fourth quartile was significantly greater than those with PTH levels in the first quartile (P-trend = 0.01). However, there was no significant association between vitamin D and any atherosclerotic phenotypes, including carotid IMT, plaques, luminal diameter, and baPWV. CONCLUSION: This suggests that PTH might affect the development of atherosclerosis by altering vascular compliance.

Difference of stage at cancer diagnosis by socioeconomic status for four target cancers of the National Cancer Screening Program in Korea: Results from the Gwangju and Jeonnam cancer registries.

BACKGROUND: The aim of this study was to evaluate whether stage at cancer diagnosis differed according to patient economic status. METHODS: A total of 10,528 patients with cancer of the stomach, colorectum, breast, or cervix, which are target organs of the Korean National Cancer Screening Program (NCSP; fully implemented in 2005) were extracted from population-based cancer registries. The patients were classified into four groups based on socioeconomic status (SES), as determined using their National Health Insurance (NHI) monthly premium at the time of cancer diagnosis. Cancer stage at diagnosis was defined as early (in situ/local) or late stage (regional/distant) based on the Surveillance, Epidemiology, and End Results (SEER) summary stage. Multivariable logistic regression analysis was performed to estimate the risk of non-local stage using age, residential area, and community deprivation index as covariates. RESULTS: The lowest SES subjects showed significantly higher risks of being diagnosed at a later stage for stomach, colorectal, and female breast cancer, but not for cervical cancer, compared with the highest SES subjects. The estimated ORs were 1.28 (95% CI, 1.10-1.49), 1.29 (95% CI, 1.03-1.61), and 1.35 (95% CI, 1.02-1.81) in the lowest SES subjects with stomach, colorectal, and breast cancer, respectively. CONCLUSIONS: In conclusion, later stage diagnoses of stomach, colon, and female breast cancer are still associated with SES in Korea in the era of the NCSP for the lower SES population.

Association between Serum 25-hydroxyvitamin D Levels and Type 2 Diabetes in Korean Adults.

Previous studies have suggested that a vitamin D deficiency increases the risk of type 2 diabetes. This study evaluated the association between serum vitamin D levels and type 2 diabetes in Korean adults. This study included 9,014 subjects (3,600 males and 5,414 females) aged ≥50 years who participated in the Dong-gu Study. The subjects were divided into groups in whom the serum vitamin D level was severely deficient (<10 ng/mL), deficient (10 to <20 ng/mL), insufficient (20 to <30 ng/mL) and sufficient (≥30 ng/mL). Type 2 diabetes was defined by a fasting blood glucose level of ≥126 mg/dL and/or an HbA1c proportion of ≥6.5% and/or self-reported current use of diabetes medication. Multiple logistic regression was performed to evaluate the association between vitamin D status and type 2 diabetes. The age- and sex-adjusted prevalence of type 2 diabetes was 22.6%, 22.5% and 18.4% and 12.7% for severely deficient, deficient, insufficient, and sufficient, respectively. Multivariate modeling revealed that subjects with insufficient or sufficient vitamin D levels were at a lower risk of type 2 diabetes than were subjects with deficient vitamin D levels [odds ratio (OR), 0.82; 95% confidence interval (CI), 0.71-0.94 and OR, 0.51; 95% CI, 0.35-0.74, respectively]. Higher serum vitamin D levels were associated with a reduced risk of diabetes in Korean adults, suggesting that vitamin D may play a role in the pathogenesis of diabetes.

Cytocompatible Polymer Grafting from Individual Living Cells by Atom-Transfer Radical Polymerization.

A cytocompatible method of surface-initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI-ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine-based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material-independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical-scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell-division studies. This work will provide a strategic approach to the generation of living cell-polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy.

Association between Vitamin D Status and Risk of Peripheral Arterial Disease: The Dong-gu Study.

Low levels of vitamin D have been associated with increased cardiovascular disease risk. However, few studies have evaluated the association between vitamin D status and peripheral arterial disease (PAD). We therefore aimed to investigate whether low 25-hydroxyvitamin D (25(OH)D) levels were associated with increased risk of PAD in the Korean population. This cross-sectional study was conducted among 8,960 subjects aged 50 years or older without known myocardial infarction or stroke. PAD was defined by an ankle brachial blood pressure index <0.9. Multivariate logistic regression was used to evaluate the association between serum 25(OH)D levels and risk of PAD. Of the 8,960 subjects, 3.0% had PAD and the age and sex adjusted prevalence of PAD decreased with the increasing 25(OH)D quartile. After adjusting for potential confounders and parathyroid hormones, serum 25(OH)D levels were associated with a significantly decreased risk of PAD (OR for one SD increase, 0.98; 95% CI, 0.95-1.0, P for trend=0.040). Compared with the first 25(OH)D quartile, the odds of PAD were 0.86 (95% CI, 0.62-1.21), 0.67 (95% CI, 0.46-0.97), and 0.71 (95% CI, 0.49-1.04) for the second, third, and fourth quartiles, respectively. In this cross-sectional study, we found that low serum 25(OH)D levels were associated with an increased risk of PAD, independent of traditional cardiovascular risk factors and parathyroid hormone. Our findings suggest that low vitamin D levels may contribute to PAD in the Korean population.

25-Hydroxyvitamin D and Parathyroid Hormone Levels Are Independently Associated with the Hemoglobin A1c Level of Korean Type 2 Diabetic Patients: The Dong-Gu Study.

In type 2 diabetic patients, the relationships between 25-hydroxyvitamin D and parathyroid hormone levels, and glycemic control, remain unclear. We evaluated associations between 25-hydroxyvitamin D, parathyroid hormone, and hemoglobin A1c levels after adjusting for other covariates, including log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels, in Korean patients with type 2 diabetes. In total, 1,175 patients with type 2 diabetes were selected from 8,857 individuals who completed the baseline survey of the Dong-gu study, conducted in Korea from 2007 to 2010. After adjusting for other covariates, we found that the mean hemoglobin A1c level was inversely associated with the 25-hydroxyvitamin D level (Q1: 7.47% [7.30-7.63], Q2: 7.25% [7.09-7.40], Q3: 7.17% [7.02-7.32], Q4: 7.19% [7.02-7.35]; p for trend = 0.021, p for between groups = 0.050) and the parathyroid hormone level (Q1: 7.35% [7.19-7.51], Q2: 7.34% [7.19-7.50], Q3: 7.28% [7.13-7.43], Q4: 7.09% [6.94-7.24]; p for trend = 0.022, p for between groups = 0.048). However, the mean fasting glucose level was not associated with either the 25-hydroxyvitamin D or parathyroid hormone level. In conclusion, inverse associations were evident between hemoglobin A1c, 25-hydroxyvitamin D and parathyroid hormone levels in Korean patients with type 2 diabetes. The associations remained significant after adjusting for other covariates, including the log transformed 25-hydroxyvitamin D levels and log transformed parathyroid hormone levels.

Plasma Folate and Vitamin B12 Levels in Patients with Hepatocellular Carcinoma.

Folate and vitamin B12 involved in the one-carbon metabolism may play a key role in carcinogenesis and progression of hepatocellular carcinoma (HCC) through influencing DNA integrity. The purpose of this study is to evaluate the association of plasma folate and vitamin B12 levels with HCC in a case-control study on 312 HCC patients and 325 cancer-free controls. Plasma concentrations of folate and vitamin B12 in all the subjects were measured by electrochemiluminescence immunoassay. Meanwhile, the information of HCC patients' clinical characteristics including tumor-node-metastasis (TNM) stage, tumor size and tumor markers were collected. The patients of HCC had significantly lower folate levels than those of controls; there was no significant difference in the mean of plasma vitamin B12 levels. We also observed an inverse association between the levels of plasma folate and HCC: the adjusted odds ratios (OR) (95% confidence intervals (CI)) of HCC from the highest to lowest quartile of folate were 0.30 (0.15-0.60), 0.33 (0.17-0.65), and 0.19 (0.09-0.38). Compared to the subjects in the lowest quartile of plasma vitamin B12, only the subjects in the highest quartile of vitamin B12 exhibited a significant positive relationship with HCC, the adjusted OR was 2.01 (95% CI, 1.02-3.98). HCC patients with Stage III and IV or bigger tumor size had lower folate and higher vitamin B12 levels. There was no significant difference in the mean plasma folate levels of the HCC cases in tumor markers status (AFP, CEA and CA19-9 levels), whereas patients with higher CEA or CA19-9 levels retained significantly more plasma vitamin B12 than those with normal-CEA or CA19-9 level. In conclusion, plasma folate and vitamin B12 levels could be associated with HCC, and might be used as predictors of clinical characteristics of HCC patients. However, further prospective studies are essential to confirm the observed results.

Mucocele After Orbital Fracture Repair Masquerading as Optic Neuritis.

The authors report a patient of mucocele formation after orbital wall fracture repair masquerading as optic neuritis.A 38-year-old man with a history of medial orbital wall fracture repair with an alloplastic implant 10 years previously, presented with left visual disturbance and mild ocular pain with movement of the left eye of 3-day duration, and a relative afferent papillary defect in his left eye. He reported having cold symptoms 2 weeks before presentation. His symptoms were typical of retrobulbar optic neuritis. Under suspicion of optic neuritis, computed tomography and magnetic resonance imaging were performed and revealed a large cyst in the sphenoid sinus and ethmoid sinus, just behind the alloplastic implant, that was compressing the medial rectus muscle and optic nerve of the left eye. The patient underwent endoscopic marsupialization of the cyst. Subsequent histologic examinations revealed a cyst lined with ciliated pseudostratified columnar epithelium. The patient had an uncomplicated postoperative course and the visual disturbance resolved. For patients who present solely with optic neuropathy after orbital fracture repair, it is important to be vigilant of potentially rare cause, mucocele formation.

Association of APOE Genotype with Bone Mineral Density in Men and Women: The Dong-gu and Namwon Studies.

Many studies have investigated relationships between APOE genotype and bone mineral density (BMD). However, the results of these studies have been inconsistent. Few studies have been carried out in Asian populations. We studied the relationship of the APOE gene polymorphism and BMD in two large population-based studies. The datasets included the Dong-gu Study (3575 men and 5335 women) and the Namwon Study (2310 men, 3512 women). Lumbar spine and femoral neck BMD were measured by dual-energy X-ray absorptiometry. APOE genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The APOE genotypes were classified into APOE E2 (E2/E2 and E2/E3), APOE E3 (E3/E3), and APOE E4 (E3/E4 and E4/E4). The genotype distribution of the study population was in Hardy-Weinberg equilibrium. There were no significant differences among APOE genotype groups in lumbar and femoral neck BMD in either cohort. Our data do not support the hypothesis that the APOE genotype is associated with BMD.

HbA1c is significantly associated with arterial stiffness but not with carotid atherosclerosis in a community-based population without type 2 diabetes: The Dong-gu study.

OBJECTIVES: We examined the associations between HbA1c levels and various atherosclerotic vascular parameters among adults without diabetes from the general population. METHODS: A total of 6500 community-dwelling adults, who were free of type 2 diabetes and ≥50 years of age, were included. High-resolution B-mode ultrasound was used to evaluate carotid artery structure, including intima-media thickness (IMT), plaque, and luminal diameter. Brachial-ankle pulse wave velocity (baPWV), which is a useful indicator of systemic arterial stiffness, was determined using an automatic waveform analysis device. RESULTS: No significant associations were observed between HbA1c, carotid IMT, plaque, or luminal diameter in a fully adjusted model. However, the odds ratio (95% confidence interval) for high baPWV (defined as the highest quartile) increased by 1.43 (1.19-1.71) per 1% HbA1c increase after adjusting for conventional risk factors in a multivariate logistic regression analysis. In addition, HbA1c was independently associated with baPWV in a multivariate linear regression analysis. CONCLUSIONS: High-normal HbA1c level was independently associated with arterial stiffness, but not with carotid atherosclerotic parameters, in the general population without diabetes. Our results suggest that the functional atherosclerotic process may already be accelerated according to HbA1c level, even at a level below the diagnostic threshold for diabetes.

The association between vitamin D and parathyroid hormone and bone mineral density: the Dong-gu Study.

The primary objective of the present study was to investigate the relationship between 25-hydroxyvitamin D (25[OH]D) and areal bone mineral density (aBMD) in Korean subjects from the general population aged ≥50 years. This study included 8,857 individuals who completed the baseline survey of the Dong-gu study, which was conducted in Korea from 2007-2010. The participants who fulfilled the detailed inclusion criteria underwent assessment of the femoral neck and lumbar spine aBMD as well as measurement of serum 25(OH)D and parathyroid hormone (PTH) levels. After adjusting for other covariates and log-PTH values, the mean aBMD of the femoral neck exhibited a significant increase with increasing 25(OH)D levels in both males (p < 0.001) and females (p = 0.005). Additionally, the mean aBMD of the lumbar spine exhibited a significant increase with increasing 25(OH)D levels in males (p = 0.011) but not females (p = 0.252). After adjusting for covariates and log-25(OH)D values, the mean aBMD values of the femoral neck and lumbar spine showed significant decreases with increasing PTH levels in both males and females (p < 0.001). The present findings demonstrate that the aBMD of the femoral neck was significantly associated with 25(OH)D levels independent of PTH in both males and females and that the aBMD of the lumbar spine was significantly associated with 25(OH)D levels independent of PTH in males, but not females.

Chemical sporulation and germination: cytoprotective nanocoating of individual mammalian cells with a degradable tannic acid-FeIII complex.

Individual mammalian cells were coated with cytoprotective and degradable films by cytocompatible processes maintaining the cell viability. Three types of mammalian cells (HeLa, NIH 3T3, and Jurkat cells) were coated with a metal-organic complex of tannic acid (TA) and ferric ion, and the TA-Fe(III) nanocoat effectively protected the coated mammalian cells against UV-C irradiation and a toxic compound. More importantly, the cell proliferation was controlled by programmed formation and degradation of the TA-Fe(III) nanocoat, mimicking the sporulation and germination processes found in nature.

APOE Polymorphism Is Associated with C-reactive Protein Levels but Not with White Blood Cell Count: Dong-gu Study and Namwon Study.

We evaluated the association of the APOE polymorphism with serum C-reactive protein levels and white blood cell count in two large population-based studies in Korean. The datasets included the Dong-gu study (n = 8,893) and the Namwon Study (n = 10,032). APOE genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism. Multivariable linear regression analysis was performed to evaluate the relationship of APOE genotypes with C-reactive protein levels and white blood cell count with adjustments for age, sex, body mass index, smoking, diabetes, hypertension, and serum lipids. In the multivariate model, carriers of E3E4 or E4E4 genotype had significantly lower C-reactive protein levels compared with carriers of E3E3 genotype group (0.50 mg/L vs. 0.67 mg/L; 0.37 mg/L vs. 0.67 mg/L, respectively, for the Dong-gu Study and 0.47 mg/L vs. 0.66 mg/L; 0.45 mg/L vs. 0.66 mg/L, respectively, for the Namwon Study). However, there was no difference in white blood cell count among APOE genotypes. We found that the APOE E4 allele is associated with lower C-reactive protein levels, but not white blood cell count. Our results suggest that APOE genotype may influence C-reactive protein levels through non-inflammatory pathway.

Estimation of the cutoff value of vitamin D: the Dong-gu study.

BACKGROUND: Vitamin D plays an essential role in bone health and growth, but the optimal serum 25-hydroxyvitamin D (25(OH)D) concentration is not known. This study was performed to investigate the optimal 25(OH)D concentration in regard to parathyroid hormone (PTH) concentration in the Korean general population aged 50 years or older. FINDINGS: The study population consisted of 8,857 subjects (3,545 men and 5,312 women) who participated in the baseline survey of the Dong-gu study, conducted in Korea between 2007 and 2010. Serum 25(OH)D and PTH concentrations were measured by chemiluminescent microparticle immunoassay. The optimal 25(OH)D concentration was estimated by using nonlinear regression model. Our data show that PTH concentration reached a theoretical plateau at 38.2 pg/ml and corresponding 25(OH)D concentration was 21.1 ng/ml in men and PTH concentration at 42.9 pg/ml and 25(OH)D concentration at 13.8 ng/ml in women. CONCLUSIONS: These results indicate that, for Korean general population aged 50 years or older, the optimal 25(OH)D concentration is 21.1 ng/ml in men and 13.8 ng/ml in women.

Cytocompatible in situ cross-linking of degradable LbL films based on thiol-exchange reaction.

Formation of both mechanically durable and programmably degradable layer-by-layer (LbL) films in a biocompatible fashion has potential applications in cell therapy, tissue engineering, and drug-delivery systems, where the films are interfaced with living cells. In this work, we developed a simple but versatile method for generating in situ cross-linked and responsively degradable LbL films, based on the thiol-exchange reaction, under highly cytocompatible conditions (aqueous solution at pH 7.4 and room temperature). The cytocompatibility of the processes was confirmed by coating individual yeast cells with the cross-linked LbL films and breaking the films on demand, while maintaining the cell viability. In addition, the processes were applied to the controlled release of an anticancer drug in the HeLa cells.

A disease modification effect of APOE E4 on the association between urinary albumin excretion and cognition in Korean adults.

BACKGROUND: No previous study examined a disease modifying effect of APOE E4 status on the association between the urinary albumin-to-creatinine ratio (UACR) and cognition. This study aimed to investigate whether APOE E4 modified the association in Korean adults. METHODS: We performed a cross-sectional study in adults aged 45 to 74 who were living in Namwon City, Republic of Korea. Cognitive function was measured with the Korean version of modified Mini-Mental State Examination (K-mMMSE) and cognitive impairment was defined as scores falling below the 25th percentile of the K-mMMSE according to age, sex, and educational attainments. RESULTS: A total of 10,190 participants (4006 men and 6184 women) were analyzed in the present study. Of these, 1698 subjects (16.7%) were APOE E4 carriers. The UACR values were negatively associated with the K-mMMSE scores, even after adjusting for potential confounders including age, sex, education, and vascular risk factors. APOE E4 modified the association significantly, resulting in a steeper decline of cognitive function with the increase in UACR in E4 carriers (P for interaction = 0.021). CONCLUSION: Higher UACR values were significantly associated with cognitive dysfunction in the general Korean population, with cognition in APOE E4 carriers being more severely affected by increased UACR.

Genetic variation in PSCA is associated with bladder cancer susceptibility in a Korean population.

BACKGROUND: Genetic factors play important roles in the pathogenesis of human cancer. A recent genome wide association study (GWAS) identified an association between the rs2294008 polymorphism of the prostate stem cell antigen (PSCA) gene and bladder cancer risk in Caucasians. The aim of this study was to determine whether the rs2294008 polymorphism is similarly associated with bladder cancer susceptibility in a Korean population. MATERIALS AND METHODS: We conducted a case-control study of 411 bladder cancer patients and 1,700 controls. RESULTS: The frequencies of the CC, CT, and TT genotypes of the rs2294008 polymorphism were 16.9, 54.0, and 28.8% in bladder cancer patients and 24.4, 48.1, and 27.5% in controls, respectively. We found that the combined CT/TT genotypes were associated with a significantly increased risk of bladder cancer (OR CT/TT=1.58, 95% CI=1.15-2.17), compared with the CC genotype. Smoking habits, tumor grade and tumor stage did not modify the association between rs2294008 and the risk of bladder cancer. CONCLUSIONS: Our study showed that the rs2294008 polymorphism in the PSCA gene is associated with the risk of bladder cancer in a Korean population, providing evidence that it may contribute to bladder carcinogenesis regardless of ethnicity.

Gender differences in the association between depressive symptoms and carotid atherosclerosis among middle-aged and older Koreans: the Namwon study.

We investigated the association of depressive symptoms with carotid intima-media thickness (IMT) and plaques in the general Korean population. A total of 7,554 Korean males and females aged 45-74 yr who were free from cardiovascular diseases were included in the analyses. Depressive symptoms were assessed by the Center for Epidemiologic Studies Depression Scale (CES-D). Subjects with a score of ≥16 were classified as having clinically significant depressive symptoms. Carotid ultrasonography was used to measure mean carotid IMT (C-IMT) and to determine the presence of plaques. A significant association between depressive symptoms and C-IMT was observed only in females. After adjustment for established cardiovascular risk factors, females with depressive symptoms had significantly greater C-IMT than females without depressive symptoms (mean difference 0.011±0.004 mm; 95% confidence interval, 0.003-0.019 mm). Compared with controls, the fully adjusted risk of females with depressive symptoms for abnormal C-IMT (≥1.0 mm) was significant (odds ratio, 1.63; 95% confidence interval, 1.16-2.30). No significant association between depressive symptoms and carotid plaques was observed in either gender. This study shows a significant association between depressive symptoms and C-IMT in middle-aged and older females.