Showing papers by "Chung-Ang University published in 2011"

Metagenomic Analysis of Kimchi, a Traditional Korean Fermented Food†

Abstract: Kimchi, a traditional food in the Korean culture, is made from vegetables by fermentation. In this study, metagenomic approaches were used to monitor changes in bacterial populations, metabolic potential, and overall genetic features of the microbial community during the 29-day fermentation process. Metagenomic DNA was extracted from kimchi samples obtained periodically and was sequenced using a 454 GS FLX Titanium system, which yielded a total of 701,556 reads, with an average read length of 438 bp. Phylogenetic analysis based on 16S rRNA genes from the metagenome indicated that the kimchi microbiome was dominated by members of three genera: Leuconostoc, Lactobacillus, and Weissella. Assignment of metagenomic sequences to SEED categories of the Metagenome Rapid Annotation using Subsystem Technology (MG-RAST) server revealed a genetic profile characteristic of heterotrophic lactic acid fermentation of carbohydrates, which was supported by the detection of mannitol, lactate, acetate, and ethanol as fermentation products. When the metagenomic reads were mapped onto the database of completed genomes, the Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 and Lactobacillus sakei subsp. sakei 23K genomes were highly represented. These same two genera were confirmed to be important in kimchi fermentation when the majority of kimchi metagenomic sequences showed very high identity to Leuconostoc mesenteroides and Lactobacillus genes. Besides microbial genome sequences, a surprisingly large number of phage DNA sequences were identified from the cellular fractions, possibly indicating that a high proportion of cells were infected by bacteriophages during fermentation. Overall, these results provide insights into the kimchi microbial community and also shed light on fermentation processes carried out broadly by complex microbial communities.

Genome-wide association study identifies FCGR2A as a susceptibility locus for Kawasaki disease.

Abstract: Kawasaki disease is a systemic vasculitis of unknown etiology, with clinical observations suggesting a substantial genetic contribution to disease susceptibility. We conducted a genome-wide association study and replication analysis in 2,173 individuals with Kawasaki disease and 9,383 controls from five independent sample collections. Two loci exceeded the formal threshold for genome-wide significance. The first locus is a functional polymorphism in the IgG receptor gene FCGR2A (encoding an H131R substitution) (rs1801274; P = 7.35 × 10(-11), odds ratio (OR) = 1.32), with the A allele (coding for histadine) conferring elevated disease risk. The second locus is at 19q13, (P = 2.51 × 10(-9), OR = 1.42 for the rs2233152 SNP near MIA and RAB4B; P = 1.68 × 10(-12), OR = 1.52 for rs28493229 in ITPKC), which confirms previous findings(1). The involvement of the FCGR2A locus may have implications for understanding immune activation in Kawasaki disease pathogenesis and the mechanism of response to intravenous immunoglobulin, the only proven therapy for this disease.

Expanding fungal pathogenesis: Cryptococcus breaks out of the opportunistic box

Abstract: Cryptococcus neoformans is generally considered to be an opportunistic fungal pathogen because of its tendency to infect immunocompromised individuals, particularly those infected with HIV. However, this view has been challenged by the recent discovery of specialized interactions between the fungus and its mammalian hosts, and by the emergence of the related species Cryptococcus gattii as a primary pathogen of immunocompetent populations. In this Review, we highlight features of cryptococcal pathogens that reveal their adaptation to the mammalian environment. These features include not only remarkably sophisticated interactions with phagocytic cells to promote intracellular survival, dissemination to the central nervous system and escape, but also surprising morphological and genomic adaptations such as the formation of polyploid giant cells in the lung.

Brains on video games

Abstract: The popular press is replete with stories about the effects of video and computer games on the brain. Sensationalist headlines claiming that video games 'damage the brain' or 'boost brain power' do not do justice to the complexities and limitations of the studies involved, and create a confusing overall picture about the effects of gaming on the brain. Here, six experts in the field shed light on our current understanding of the positive and negative ways in which playing video games can affect cognition and behaviour, and explain how this knowledge can be harnessed for educational and rehabilitation purposes. As research in this area is still in its early days, the contributors of this Viewpoint also discuss several issues and challenges that should be addressed to move the field forward.

A smart polysaccharide/drug conjugate for photodynamic therapy.

Abstract: Recent improvements in drug-carrier design for photodynamic therapy (PDT) have brought about significant advances for treating skin, breast, and lung tumors. The local high-dose strategy of PDT suggests beneficial therapeutic efficacy with high selectivity when using photosensitizing drugs for the target site, as well as reduced side effects for normal tissues. A variety of drug-carrying vehicles, such as nanoparticles, drug conjugates, and polymeric micelles have frequently exhibited characteristics that may make possible the successful delivery of photosensitizing drugs, thus improving cell entry and residence in tumor sites. However, these approaches have, thus far, achieved rather limited success, owing primarily to the practical obstacles inherent to natural in vivo conditions. In this study, we describe a novel molecular “Trojan horse” system that quickly switches into an aggressive molecule for tumor destruction within the environment of the tumor. Advances in functionality have enabled our system to exhibit an intelligent switch from a threedimensional supramolecular assembly (i.e., self-quenched state of photosensitizing drugs) into extended random molecules (i.e., dequenched state for singlet-oxygen production), which corresponds to a change in surface charge (Figure 1). This system may be more significant than any known photosensitizing drug conjugate thus far developed.

The roles of transparency and trust in the relationship between corruption and citizen satisfaction

Abstract: Reducing corruption and improving citizen satisfaction are important aims of government, yet the link between these two policy aims has rarely been explored This article reports a study into the r

Longitudinal Tear of the Medial Meniscus Posterior Horn in the Anterior Cruciate Ligament–Deficient Knee Significantly Influences Anterior Stability

Abstract: Background: Longitudinal tears of the medial meniscus posterior horn (MMPH) are commonly associated with a chronic anterior cruciate ligament (ACL) deficiency. Many studies have demonstrated the importance of the medial meniscus in terms of limiting the amount of anterior-posterior tibial translation in response to anterior tibial loads in ACL-deficient knees.Hypothesis: An MMPH tear in an ACL-deficient knee increases the anterior-posterior tibial translation and rotatory instability. In addition, MMPH repair will restore the tibial translation to the level before the tear.Study Design: Controlled laboratory study.Methods: Ten human cadaveric knees were tested sequentially using a custom testing system under 5 conditions: intact, ACL deficient, ACL deficient with an MMPH peripheral longitudinal tear, ACL deficient with an MMPH repair, and ACL deficient with a total medial meniscectomy. The knee kinematics were measured at 0°, 15°, 30°, 60°, and 90° of flexion in response to a 134-N anterior and 200-N axia...

Amine-modified single-walled carbon nanotubes protect neurons from injury in a rat stroke model

Abstract: Stroke results in the disruption of tissue architecture and is the third leading cause of death in the United States. Transplanting scaffolds containing stem cells into the injured areas of the brain has been proposed as a treatment strategy, and carbon nanotubes show promise in this regard, with positive outcomes when used as scaffolds in neural cells and brain tissues. Here, we show that pretreating rats with amine-modified single-walled carbon nanotubes can protect neurons and enhance the recovery of behavioural functions in rats with induced stroke. Treated rats showed less tissue damage than controls and took longer to fall from a rotating rod, suggesting better motor functions after injury. Low levels of apoptotic, angiogenic and inflammation markers indicated that amine-modified single-walled carbon nanotubes protected the brains of treated rats from ischaemic injury.

Genome Variation in Cryptococcus gattii, an Emerging Pathogen of Immunocompetent Hosts

Abstract: Cryptococcus gattii recently emerged as the causative agent of cryptococcosis in healthy individuals in western North America, despite previous characterization of the fungus as a pathogen in tropical or subtropical regions. As a foundation to study the genetics of virulence in this pathogen, we sequenced the genomes of a strain (WM276) representing the predominant global molecular type (VGI) and a clinical strain (R265) of the major genotype (VGIIa) causing disease in North America. We compared these C. gattii genomes with each other and with the genomes of representative strains of the two varieties of Cryptococcus neoformans that generally cause disease in immunocompromised people. Our comparisons included chromosome alignments, analysis of gene content and gene family evolution, and comparative genome hybridization (CGH). These studies revealed that the genomes of the two representative C. gattii strains (genotypes VGI and VGIIa) are colinear for the majority of chromosomes, with some minor rearrangements. However, multiortholog phylogenetic analysis and an evaluation of gene/sequence conservation support the existence of speciation within the C. gattii complex. More extensive chromosome rearrangements were observed upon comparison of the C. gattii and the C. neoformans genomes. Finally, CGH revealed considerable variation in clinical and environmental isolates as well as changes in chromosome copy numbers in C. gattii isolates displaying fluconazole heteroresistance.

Bandwidth-enhanced and polarisation-insensitive metamaterial absorber using double resonance

Abstract: A bandwidth-enhanced microwave absorber using a double resonant metamaterial is presented. Its bandwidth is increased compared with previous metamaterial absorbers. The proposed absorber has a thin configuration and its performance is constant for different polarisations. Numerical and experimental results support the proposed absorber's performance.

Compact Coplanar Waveguide (CPW)-Fed Zeroth-Order Resonant Antennas With Extended Bandwidth and High Efficiency on Vialess Single Layer

Abstract: This paper presents the design and analysis of compact coplanar waveguide (CPW)-fed zeroth-order resonant (ZOR) antennas. They are designed on a CPW single layer where vias are not required. The ZOR phenomenon is employed to reduce the antenna size. The novel composite right/left-handed (CRLH) unit cell on a vialess single layer simplifies the fabrication process. In addition, the CPW geometry provides high design freedom, so that bandwidth-extended ZOR antennas can be designed. The antenna's bandwidth is characterized by the circuit parameters. Based on the proposed bandwidth extension technique, symmetric, asymmetric, and chip-loaded antennas are designed. The ZOR characteristic and bandwidth extension are verified by a commercial EM simulator. Their performances are compared with those of previously reported metamaterial resonant antennas. They provide further size reduction, higher efficiency, easier manufacturing, and extended bandwidth.

Fabrication of graphene thin films based on layer-by-layer self-assembly of functionalized graphene nanosheets.

Abstract: In this study, we present a facile means of fabricating graphene thin films via layer-by-layer (LbL) assembly of charged graphene nanosheets (GS) based on electrostatic interactions. To this end, graphite oxide (GO) obtained from graphite powder using Hummers method is chemically reduced to carboxylic acid-functionalized GS and amine-functionalized GS to perform an alternate LbL deposition between oppositely charged GSs. Specifically, for successful preparation of positively charged GS, GOs are treated with an intermediate acyl-chlorination reaction by thionyl chloride and a subsequent amidation reaction in pyridine, whereby a stable GO dispersibility can be maintained within the polar reaction solvent. As a result, without the aid of additional hybridization with charged nanomaterials or polyelectrolytes, the oppositely charged graphene nanosheets can be electrostatically assembled to form graphene thin films in an aqueous environment, while obtaining controllability over film thickness and transparency....

A Planar {Mn19(OH)12}26+ Unit Incorporated in a 60-Tungsto-6-Silicate Polyanion†

Abstract: Polyoxometalates (POMs) are discrete metal–oxo anions of early transition-metals in high oxidation states (e.g. W, Mo, V) and they are usually synthesized in aqueous, acidic medium. Most classical POMs are based on edgeand corner-shared MO6 octahedra. However, the recently discovered POM subclass of noble metalates comprises linked square-planar MO4 units (M = Pd , Au). Lacunary (vacant) POMs can be considered as inorganic, multidentate ligands, and hence they are good candidates for the encapsulation of large, multinuclear dand f-block metal–oxo fragments, sometimes resulting in compounds with interesting magnetic properties. A pioneering result in this area was the synthesis of [Mn12(CH3COO)16(H2O)4O12] (Mn12) by Lis in 1980, which was shown to exhibit single-molecule magnet (SMM) behavior by Gatteschi s group 13 years later. During the past two decades many high-nuclearity, transition-metal based, coordination complexes with interesting electronic and magnetic properties have been prepared. High-nuclearity manganese complexes have been amongst the most studied in this class, and there are examples containing up to 84 manganese ions. 6] To date there are only a few high-nuclearity manganese– oxo-containing POMs, such as {[XW9O34]2[Mn III 4Mn II 2O4(H2O)4]} 12 (X = Si, Ge) and [Mn13Mn O12(PO4)4(PW9O34)4] 31 . Herein we report the synthesis and structure as well as the magnetic and electrochemical properties of a 19 manganese(II) center containing 60-tungsto-6-silicate, [Mn19(OH)12(SiW10O37)6] 34 (1), which was isolated as a hydrated sodium salt, Na34[Mn19(OH)12(SiW10O37)6]·115H2O (Na-1). Single-crystal X-ray diffraction revealed that polyanion 1 consists of a cationic {Mn19(OH)12} 26+ (Mn19) assembly stabilized by six dilacunary [a-SiW10O37] 10 units resulting in a structure with S6 point-group symmetry (Figure 1, top). To the best of our knowledge, 1 is the highest nuclearity manganesecontaining POM known to date. All 19 Mn ions lie in the same plane forming a hexagonal structure based on edgeshared MnO6 octahedra. The Mn II ions in Mn19 are connected by a total of twelve m3-hydroxo bridges, as determined by bond valence sum (BVS) calculations (Supporting Information, Table S1). The discrete Mn19 nanosheet (Figure 1, bottom) is held in place by six dilacunary [a-SiW10O37] 10

The Efficacy of Autologous Platelet Rich Plasma Combined with Ablative Carbon Dioxide Fractional Resurfacing for Acne Scars: A Simultaneous Split-Face Trial

Abstract: BACKGROUNDAblative carbon dioxide (CO2) fractional resurfacing is a promising therapeutic intervention for the treatment of acne scars, although this technique is associated with prolonged surgical site erythema and edema, which may affect the daily lives of patients. Autologous platelet-rich plasma

Prevalence of chronic obstructive pulmonary disease in Korea: The fourth Korean National Health and Nutrition Examination Survey, 2008

Abstract: Background and objective: Because the mortality and social burden associated with COPD is increasing, repeated surveys of the prevalence of COPD have been used to assess risk factors, detect potential patients, and establish early diagnoses and management protocols. We report the prevalence of spirometrically detected COPD in Korea in 2008, using data from the fourth Korean National Health and Nutrition Survey. Methods: Using nationwide stratified random sampling, based on the Korean Statistical Office census, 6840 subjects aged ≥19 years underwent spirometry, which was performed by four trained technicians, during 2008. The place of residence, levels of education and income and smoking status, as well as other results from a COPD survey questionnaire were also assessed. Results: Airflow obstruction (FEV1/FVC < 0.7) was detected in 8.8% of subjects aged ≥19 years (11.6% of men and 5.9% of women) and COPD was detected in 13.4% of subjects aged ≥40 years (19.4% of men and 7.9% of women). Of the 6840 subjects, 27.3% were current smokers and 17.2% were former smokers, and the prevalence of COPD was higher in current and former smokers than in never smokers. Approximately 94% of patients with COPD had mild-to-moderate disease, without apparent symptoms; only 2.4% had been diagnosed by a physician and only 2.1% of patients had been treated. The independent risk factors for COPD were smoking, advanced age and male gender. Conclusions: Although the prevalence of COPD in Korea is high, the disease is underdiagnosed and most COPD patients are under-treated.

Incidence and Mortality Following Hip Fracture in Korea

Abstract: The authors evaluated the incidence of hip fracture and subsequent mortality in Korea using nationwide data obtained from the Health Insurance Review and Assessment Service. This study was performed on patient population, aged 50-yr or older who underwent surgical procedures because of hip fracture (ICD10; S720, S721). All patients were followed using patient identification code to identify deaths. Crude hip fracture rates increased from 191.9/100,000 in 2005 to 207.0/100,000 in 2008 in women and from 94.8/100,000 in 2005 to 97.8/100,000 in 2008, in men respectively. Crude mortality within 12 months after hip fracture showed a similar trend (18.8% in 2005 and 17.8% in 2007). The mean of standardized mortality ratio of hip fracture was 6.1 at 3 months, 3.5 at 1 yr, and 2.3 at 2 yr post-fracture. The increasing incidence and the high mortality after hip fracture are likely to become serious public health problems and a public health program should begin to prevent hip fractures in Korea.

Wettability changes of TiO 2 nanotube surfaces

Abstract: This study examines the effect of environmental and experimental conditions, such as temperature and time, on the wettability properties of titania nanotube (TNT) surfaces fabricated by anodization. The fabricated TNTs are 60–130 nm inner diameter and 7–10 µm height. One-microliter water droplets were used to define the wettability of the TNT surfaces by measuring the contact angles. A digital image analysis algorithm was developed to obtain contact angles, contact radii and center heights of the droplets on the TNT surfaces. Bare titanium foil is inherently less hydrophilic with approximately 60°–80° contact angle. The as-anodized TNT surfaces are more hydrophilic and annealing further increases this hydrophilic property. Furthermore, it was found that the TNT surface became more hydrophobic when aged in air over a period of three months. It is believed that the surface wettability can be changed due to alkane contamination and organic contaminants in an ambient atmosphere. This work can provide guidelines to better specify the environmental conditions that changes surface properties of TNT surfaces and therefore affect their desirable function in specific applications such as orthopedic implants.

Use of Organic Acids to Inactivate Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on Organic Fresh Apples and Lettuce

Abstract: This study was undertaken to investigate the antimicrobial effect of organic acids against Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on whole red organic apples and lettuce. Several studies have been conducted to evaluate organic acids as sanitizers. However, no studies have compared antimicrobial effects of various organic acids on organic fresh produce, including evaluation of color changes of produce. Apples and lettuce were inoculated with a cocktail of 3 strains each of 3 foodborne pathogens provided above and treated with 1% and 2% organic acids (propionic, acetic, lactic, malic, and citric acid) for 0, 0.5, 1, 5, and 10 min. With increasing treatment time and acid concentration, organic acid treatments showed significant reduction compared to the control treatment (distilled water), and differences in antimicrobial effects between organic acids were observed. After 10 min of treatment with 1% and 2% organic acids in apples, propionic (0.92 to 2.75 log reduction), acetic (0.52 to 2.78 log reduction), lactic (1.69 to >3.42 log reduction), malic (1.48 to >3.42 log reduction), and citric acid (1.52 to >3.42 log reduction) exhibited significant (P < 0.05) antibacterial effects against 3 foodborne pathogens compared to the control treatment. In lettuce, propionic (0.93 to 1.52 log reduction), acetic (1.13 to 1.74 log reduction), lactic (1.87 to 2.54 log reduction), malic (2.32 to 2.98 log reduction), and citric acid (1.85 to 2.86 log reduction) showed significant (P < 0.05) effects compared to the control treatment. Changes in sample color subjected to organic acids treatment were not significant during storage. Practical Application: It is suggested that organic acids have a potential as sanitizers for organic fresh produce. These data may help the organic produce industry provide safe fresh produce for consumers.

Subchronic inhalation toxicity of gold nanoparticles

Abstract: Gold nanoparticles are widely used in consumer products, including cosmetics, food packaging, beverages, toothpaste, automobiles, and lubricants. With this increase in consumer products containing gold nanoparticles, the potential for worker exposure to gold nanoparticles will also increase. Only a few studies have produced data on the in vivo toxicology of gold nanoparticles, meaning that the absorption, distribution, metabolism, and excretion (ADME) of gold nanoparticles remain unclear. The toxicity of gold nanoparticles was studied in Sprague Dawley rats by inhalation. Seven-week-old rats, weighing approximately 200 g (males) and 145 g (females), were divided into 4 groups (10 rats in each group): fresh-air control, low-dose (2.36 × 104 particle/cm3, 0.04 μg/m3), middle-dose (2.36 × 105 particle/cm3, 0.38 μg/m3), and high-dose (1.85 × 106 particle/cm3, 20.02 μg/m3). The animals were exposed to gold nanoparticles (average diameter 4-5 nm) for 6 hours/day, 5 days/week, for 90-days in a whole-body inhalation chamber. In addition to mortality and clinical observations, body weight, food consumption, and lung function were recorded weekly. At the end of the study, the rats were subjected to a full necropsy, blood samples were collected for hematology and clinical chemistry tests, and organ weights were measured. Cellular differential counts and cytotoxicity measurements, such as albumin, lactate dehydrogenase (LDH), and total protein were also monitored in a cellular bronchoalveolar lavage (BAL) fluid. Among lung function test measurements, tidal volume and minute volume showed a tendency to decrease comparing control and dose groups during the 90-days of exposure. Although no statistically significant differences were found in cellular differential counts, histopathologic examination showed minimal alveoli, an inflammatory infiltrate with a mixed cell type, and increased macrophages in the high-dose rats. Tissue distribution of gold nanoparticles showed a dose-dependent accumulation of gold in only lungs and kidneys with a gender-related difference in gold nanoparticles content in kidneys. Lungs were the only organ in which there were dose-related changes in both male and female rats. Changes observed in lung histopathology and function in high-dose animals indicate that the highest concentration (20 μg/m3) is a LOAEL and the middle concentration (0.38 μg/m3) is a NOAEL for this study.

The incidence and residual lifetime risk of osteoporosis-related fractures in Korea

Abstract: Although the Korean population does not have high risk for osteoporosis, the numbers of osteoporosis-related fractures represent a considerable economic burden to society. The purpose of this study was to determine the incidence and residual lifetime risk of osteoporosis-related fractures in Korea, using data from the Health Insurance Review and Assessment Service (HIRA), which includes nationwide information compiled by the Korean government. All new visits or admissions to Korean clinics or hospitals for fractures were recorded prospectively in a nationwide cohort by the Korean HIRA using the International Classification of Diseases, 10th revision, codes and procedure codes. These data were retrospectively evaluated to determine the incidence and residual lifetime risk of osteoporosis-related fractures (hip, spine, distal radius, and humerus fractures), in men and women aged 50 years or more between 2005 and 2008. The annual incidences of osteoporosis-related fractures were 1,661, 1,646, 1,623, and 1,614 per 100,000 person-years in men and women aged 50 years or more from the year 2005 to 2008. The annual incidence of osteoporosis-related fracture in women was three times that of men. The incidence of osteoporosis-related fractures increased with advancing age. In Korea, at the age of 50 years, the residual lifetime probabilities of osteoporosis-related fractures are 59.5% for women and 23.8% for men. This study presents the baseline data for treatment and research on osteoporosis and provides an estimate of osteoporosis-related fractures in Korea.

Intense focused ultrasound tightening in Asian skin: clinical and pathologic results.

Abstract: BACKGROUND Laxity and wrinkles of the aging face are common cosmetic concerns. Intense focused ultrasound (IFUS), a novel treatment modality for skin laxity, produces thermal effects at various depths while sparing overlying epidermis. OBJECTIVE To evaluate the safety and efficacy of IFUS in facial skin tightening. METHODS AND MATERIALS Twenty-two Korean patients with facial laxity were analyzed after a single IFUS treatment. Patient assessments were recorded, and two blinded, experienced clinicians who assessed improvement of nasolabial folds and jaw tightening evaluated photographs of patients and rated skin laxity. Skin biopsies were taken from 11 patients before and 2 months after treatment. RESULTS Objectively, nasolabial folds and jaw lines were improved in all patients. Subjectively, 77% of patients reported much improvement of nasolabial folds, and 73% of patients reported much improvement at the jaw line. Histologic evaluation of skin biopsy samples using hematoxylin and eosin and Victoria blue stains showed greater dermal collagen with thickening of the dermis and straightening of elastic fibers in the reticular dermis after treatment. CONCLUSION IFUS is a safe, effective, noninvasive procedure to tighten the facial skin of Asian patients. Improvement is associated with greater production of dermal collagen and straightening of dermal elastic fibers. The authors have indicated no significant interest with commercial supporters.

A randomized, double-blind, placebo-controlled multicenter trial of saccharomyces boulardii in irritable bowel syndrome: effect on quality of life.

Abstract: BackgroundProbiotics confer health benefits to the host. However, its clinical effect on irritable bowel syndrome (IBS) is controversial.AimsThis study was aimed to evaluate the effects of Saccharomyces boulardii on quality of life (QOL) and symptoms in patients with diarrhea-predominant IBS or mixe