Molecular Detection of Parvovirus in Manchurian Chipmunks (Tamias sibiricus asiaticus) Captured in Korea.

Cross-species transmission of viral diseases alarms our global community for its potential of novel pandemic events. Of various viral pathogens noted recently, parvoviruses have posed public health threats not only to humans but also to wild animals. To investigate the prevalence of parvoviruses in wild Manchurian chipmunks, here we detected genetic fragments of the nonstructural protein of parvovirus by polymerase chain reaction in wild Manchurian chipmunk specimens captured in the central and southern regions of South Korea and compared their sequence homology with references. Of a total of 348 specimens examined, chipmunk parvovirus (ChpPV)-specific gene fragments were detected with a 31.32% rate (109 chipmunks of 348) in their kidney, liver, lung, and spleen samples, and the chipmunks captured in Gangwon Province exhibited the highest positive rate (45.37%), followed by Gyeongsang (35.29%), Gyeonggi (31.03%), Chungcheong (20.00%), and Jeolla (19.70%). When compared with the reference sequences, a partial ChpPV sequence showed 97.70% identity to the previously reported Korean strain at the nucleic acid level. In the phylogenetic analysis, ChpPV exhibited closer relationship to primate parvoviruses, erythroviruses, and bovine parvovirus than to adeno-associated viruses. Despite limited sample size and genetic sequences examined in this study, our results underline the prevalence of ChpPV in Korea and emphasize the need of close surveillance of parvoviruses in wild animals.

Comparison of Intravascular Injection Rate Between Blunt and Sharp Needles During Cervical Transforaminal Epidural Block.

BACKGROUND: Cervical transforaminal epidural block (CTEB) is a useful option in the diagnosis and treatment of cervical radicular pain. However, inadvertent intravascular injection can lead to severe neurologic complications. Blunt needles are considered to displace instead of penetrate vessels because of their dull needle tip. OBJECTIVES: To investigate whether there is a difference between blunt and sharp needles in intravascular injection rates during CTEB. STUDY DESIGN: Prospective, randomized, clinical trial. SETTING: A tertiary hospital in South Korea. METHODS: After institutional review board approval, 108 patients undergoing CTEB for treatment of radicular pain resulting from spinal stenosis and herniated nucleus pulposus were randomly assigned to one of 2 needle groups (blunt needle or sharp needle). The needle position was confirmed using biplanar fluoroscopy, and 2 mL of nonionic contrast medium was injected to detect intravascular injection. Intravascular injection was defined as the contrast medium spreading out through the vascular channel during injection under real-time fluoroscopy. This study was registered in ClinicalTrials.gov. RESULTS: The intravascular injection rate was not significantly different between the blunt needle and sharp needle groups (35.2% vs. 33.3%, P > 0.05). The procedure time was longer in the blunt needle group than in the sharp needle group (101.00 ± 12.4 seconds vs. 56.67 ± 8.3 seconds, P < 0.001). LIMITATIONS: This was a single-center study. Additionally, the physicians could not be blinded to the type of needle used. CONCLUSIONS: In the present study, use of a blunt needle did not reduce the rate of intravascular injection during CTEB compared to use of a sharp needle. In addition, procedure time significantly increased with blunt needle use compared to sharp needle use. KEY WORDS: Analgesia, bleeding, blunt needle, cervical spine, clinical trials, complications, intravascular injection, radiculopathy, sharp needle, transforaminal epidural block.

Enhanced Antioxidant Activity of Bioactives in Colored Grains by Nano-Carriers in Human Lens Epithelial Cells.

The use of phytochemicals for preventing chronic diseases associated with oxidative stress such as cataracts is hindered by their low bioavailability. The effects of nano-carriers on the antioxidant activities of extracts of black rice with giant embryo (BRGEx) and soybeans (SBx) have been determined in human lens epithelial B3 cells. Scanning (SEM) and transmission electron microscopy (TEM) demonstrated that rGO (reduced graphene oxide) has a flat surface unlike GO (graphene oxide), which has a distinctive wrinkled structure with defects. UPLC analysis revealed 41.9 µg/100 g of γ-oryzanols in water extract of BRGE, and 111.8 µg /100 g of lutein, 757.7 µg/100 g of γ-tocotrienol, 4071.4 µg/100 g of γ-tocopherol in 40% ethanol extract of soybeans, respectively. Even though a low concentration of BRGEx alone did not show any antioxidant activity in B3 cells, co-treatment of BRGEx with rGO together substantially reduced hydrogen peroxide and methylglyoxal-induced DNA damage, as determined by phosphorylated γH2AX. In addition, SBx with rGO also attenuated DNA damage. Furthermore, intracellular reactive oxygen species were significantly decreased by combining extracts of these colored grains with rGO. These results suggest a potential application of nanocarriers for enhancing the bioavailability of phytochemicals.

Low Temperature Synthesis of Rutile TiO2 Nanocrystals and Their Photovoltaic and Photocatalytic Properties.

We report a novel method of synthesizing rutile TiO2 nanocrystals at low temperature (200 degrees C) via a butanol rinsing process followed by heat treatment in an O2 atmosphere. The rutile nanocrystals show uniform size distribution of approximately 20 nm and good crystallinity confirmed by X-ray diffraction and transmission electron microscopy. A mechanism for the low temperature synthesis of rutile nanocrystals is rationalized in terms of an explosive thermal decomposition reaction of butoxy groups on TiO2 powders with O2 gas. Characterizations of the photovoltaic and photocatalytic properties of rutile nanocrystals exhibited higher photoactivity than large-sized conventional rutile powder, which demonstrates that this novel synthesis technology could expand applications of rutile powders to various photoactive devices beyond solar cells and photocatalysts.

Effect of HCl and H2SO4 treatment of TiO2 powder on the photosensitized degradation of aqueous rhodamine B under visible light.

The acid treatments of TiO2 nanopowder with HCI or H2SO4 solution increase the concentration of the hydroxyl group on TiO2 surfaces compared to bare TiO2, which acts as a Brønsted acid site. For the case of the HCl-treated TiO2, the dissociation of Brønsted acid (proton donor) sites on TiO2 leads to a drop in the pH levels of rhodamine B (RhB) dye solutions (leading to the protonation of the RhB molecule), which allows the physisorption of the uncharged carboxyl acid group on the positively charged TiO2 surface. The carboxyl acid group is believed to afford a more efficient charge injection from the Visible-light-excited RhB to the conduction band of TiO2 compared to the N-ethyl group, yielding a significantly enhanced photodegradation of RhB mainly via the N-de-ethylation pathway. For the case of the H2SO4-treated TiO2, although the dissociation of Brønsted acid sites on TiO2 is also achieved, its photoactivity is much lower than that of the HCl-treated TiO2. It seems that the presence of SO4(2-) on the H2SO4-treated TiO2 behaves as an *OH scavenger to prevent the photodegradation of the dye.

Prevalence of Antimicrobial Resistance in Escherichia coli Strains Isolated from Fishery Workers.

OBJECTIVES: This study aimed to characterize the prevalence of antibiotic resistance in Escherichia coli isolates from the fecal samples of fishery workers who work in fish farms and often use antibiotics for the feeding fishes. METHODS: Seventy-three E. coli strains isolated from the fecal samples of fishery workers and 180 isolates from a control group of restaurant workers were tested for antibiotic resistance by agar disk diffusion with 16 antimicrobial agents. RESULTS: About 30% of isolates from each group showed antimicrobial resistance to ampicillin, and 60% of isolates from fishery workers and 41% from restaurant workers were resistant to tetracycline. The isolates showed higher resistance to cephalothin and cefoxitin than to other cephem antibiotics and to gentamicin than to other aminogycosides. Our data indicated that fecal E. coli isolates from fishery workers showed higher antibiotic resistance than those of non-fishery workers (restaurant workers), especially to cephalothin, tetracycline, and trimethoprim-sulfamethoxazole (p < 0.05). However, rates of multidrug resistance were similar among the fishery workers and restaurant workers. CONCLUSION: Frequent use of antibiotics may cause increased antibiotic resistance in the human microbiome.

Downregulation of RNAIII in vancomycin-intermediate Staphylococcus aureus strains regardless of the presence of agr mutation.

Reduced vancomycin susceptibility in Staphylococcus aureus can cause serious problems relating to treatment failure and persistent infection. We investigated vancomycin susceptibility, genetic relationships and transcriptional changes of the accessory gene regulator (agr) in vancomycin-intermediate S. aureus (VISA) strains isolated from South Korea compared with vancomycin-susceptible S. aureus (VSSA) strains. Molecular characterization, population analysis profiling, agr sequencing and transcriptional profiling of RNAIII by real-time RT-PCR were performed. Of 16 VISA strains tested, eight exhibited ST5, agr II and type II SCCmec. The others exhibited ST239, agr I and type III SCCmec. A point mutation in AgrA (Asp8Gly or Ile238Lys) was found in only five VISA strains; no mutations were detected in the other strains. However, RNAIII levels markedly decreased in all VISA strains (mean of 1.39-fold change) compared with the VSSA strains (31.51-fold change) in late-exponential phases (P<0.0001). The downregulation of RNAIII could be an important genetic event in the VISA strains, regardless of the presence or absence of the agr mutation.

Pregnancy-induced hypertension, but not gestational diabetes mellitus, is a risk factor for venous thromboembolism in pregnancy.

BACKGROUND AND OBJECTIVES: The aim of this study was to identify the association of pregnancy-induced hypertension (PIH) or gestational diabetes mellitus (GDM) with the development of venous thromboembolism (VTE). SUBJECTS AND METHODS: This was a retrospective study of 57,009 pregnancies during 2002-2008 at Cheil General Hospital, Kwandong University. The diagnosis of VTE {deep vein thrombosis or pulmonary embolism (PE)} was based on clot visualization via ultrasound or computed tomography. RESULTS: In total, 27 cases (PE, 20 cases) were detected. The incidence of VTE was 0.47 per 1,000 pregnancies. To determine risk factors associated with pregnancy-induced VTE, univariate analysis using a chi-square test was performed. Cesarean (C)-section, multiple pregnancy, PIH, placenta previa, and assisted reproduction technique (ART) were statistically significant compared to the controls (all, p=0.000). However, age, premature rupture of membrane, and GDM were not statistically related to VTE. Logistic regression analysis was used to calculate the odds ratios for the risk factors. Placenta previa showed a 12.6-fold higher risk, while PIH had a 9.8-fold higher risk for the occurrence of VTE. C-section and ART procedures increased the risk of VTE by 4.2 times compared to that of the controls. CONCLUSION: Placenta previa and PIH were significant risk factors for VTE, whereas the known traditional risk factors of increased age and GDM were not found to be associated with VTE.

Two variants of staphylococcal cassette chromosome mec type IVA in community-associated meticillin-resistant Staphylococcus aureus strains in South Korea.

Meticillin-resistant Staphylococcus aureus (MRSA) strains harbouring staphylococcal cassette chromosome mec (SCCmec) type IVA are known to be more prevalent in South Korea than in other countries. Variations in the SCCmec IVA structure have been identified, including in sequence type (ST) 1 and ST72 strains. This study compared and investigated the genetic characteristics of two subtypes common in South Korea. Type IVA SCCmec of ST1 strains was characterized by type IV features with the linearized pUB110 at the junkyard (J) 3 region. However, that of ST72 strains carried a variant class B mec complex, ccrA2, with an identity of approximately 96 % and the linearized pUB110 at the J3 region. In SCCmec of ST72 strains, the organization of the class B variant and the J3 region may be more similar to that of type IA than to other types, but the ccr type and other J regions seemed to be derived from type IV. These genetic characteristics showed that type IVA appears to result from the dynamic genetic exchange and recombination of SCC DNA.

Emergence of community-associated methicillin-resistant Staphylococcus aureus strains as a cause of healthcare-associated bloodstream infections in Korea.

BACKGROUND: The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains causing bloodstream infection (BSI) has not been studied in Korea. OBJECTIVE: We sought to determine the prevalence of CA-MRSA strains among isolates recovered from patients with MRSA BSIs and to explore epidemiological changes in Korea. We also sought to evaluate clinical characteristics relevant to the development of healthcare-associated BSIs. METHODS: We prospectively collected consecutive MRSA isolates from patients with BSI at 4 hospitals from July 1 through November 30, 2007, and we also included MRSA isolates recovered from culture of blood samples collected during a previous year (October 1, 2004 through September 30, 2005) at a different hospital. Molecular typing studies were performed, including pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Staphylococcus protein A (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing. We compared the clinical characteristics and outcomes of patients with healthcare-associated BSI due to CA-MRSA strains with those of patients with healthcare-associated BSI due to healthcare-associated MRSA (HA-MRSA) strains. RESULTS: There were 76 cases of MRSA BSI, of which 4 (5.3%) were community-associated and 72 (94.7%) were healthcare-associated. Among the 72 HA-MRSA BSIs, 18 (25%) were community onset, and 54 (75%) were hospital onset. PFGE type D-ST72-spa B-SCCmec type IVA MRSA, the predominant genotype of CA-MRSA in Korea, accounted for 19 (25%) of all 76 MRSA BSIs, including 17 (23.6%) of 72 HA-MRSA BSIs and 11 (20.8%) of 53 hospital-onset HA-MRSA BSIs. Patients with healthcare-associated BSIs due to CA-MRSA strains carrying SCCmec type IVA tended to have fewer healthcare-associated risk factors, compared with patients with healthcare-associated BSIs due to HA-MRSA strains carrying other SCCmec types. The presence of a central venous catheter or other invasive device was the only independent factor differentiating patients infected with hospital-associated genotype strains from patients infected with other strains. Clinical outcomes were similar between both groups. CONCLUSIONS: CA-MRSA strains are emerging as a major cause of BSI in healthcare settings in Korea. This changing epidemiology of MRSA poses a challenge to public health and infection control in hospital settings.

Effect of MMT concentration on tribological behavior of MMT/Epoxy nanocomposite.

Numerous studies have investigated the material properties of clay/polymer nanocomposites, such as their fracture toughness, elastic modulus, and hardness. However, only a few researchers have studied the tribological properties of clay/polymer nanocomposites. This study investigated the effect of the montmorillonite (MMT) concentration on the tribological behavior of MMT/epoxy nanocomposites. Wear tests were performed on MMT/epoxy nanocomposites with four different clay concentration levels to characterize the improvement in wear behavior due to the MMT concentration. In order to examine the tribological mechanism depending on the clay concentration level, SEM analysis was performed on the worn surfaces after the wear tests. The results showed that the friction coefficient of an MMT/epoxy nanocomposite with a low MMT concentration was larger than that of a nanocomposite with a high MMT concentration. It is believed that the phenomena occur due to the action of MMT as a reinforcement and lubricant material and reduce the wear rate with increasing MMT concentration.

Non-equilibrium molecular dynamics simulation of nanojet injection with adaptive-spatial decomposition parallel algorithm.

An Adaptive-Spatial Decomposition parallel algorithm was developed to increase computation efficiency for molecular dynamics simulations of nano-fluids. Injection of a liquid argon jet with a scale of 17.6 molecular diameters was investigated. A solid annular platinum injector was also solved simultaneously with the liquid injectant by adopting a solid modeling technique which incorporates phantom atoms. The viscous heat was naturally discharged through the solids so the liquid boiling problem was avoided with no separate use of temperature controlling methods. Parametric investigations of injection speed, wall temperature, and injector length were made. A sudden pressure drop at the orifice exit causes flash boiling of the liquid departing the nozzle exit with strong evaporation on the surface of the liquids, while rendering a slender jet. The elevation of the injection speed and the wall temperature causes an activation of the surface evaporation concurrent with reduction in the jet breakup length and the drop size.

Enteric bacteria isolated from acute diarrheal patients in the Republic of Korea between the year 2004 and 2006.

In an epidemiological survey of human enterobacterial infections in the Republic of Korea during three years from 2004 to 2006, we isolated 1,784 (6.2%, isolation rate of enteropathogens from stool samples) in 2004, 2,547 (9.5%) in 2005 and 3,506 bacteria (12.3%) from people who visited clinics. Among the isolated bacteria, pathogenic Escherichia coli, especially, EAEC was the most frequently identified pathogen in both urban and rural regions followed by Staphylococcus aureus, Salmonella species, Bacillus cereus, Vibrio parahaemolyticus, Campylobacter jejuni, Clostridium perfringens, and Shigella species. Distinct seasonality was found in V. parahaemolyticus species, while this pathogen showed no age-specific patterns. However, other bacteria, i.e., pathogenic E. coli, S. aureus, Salmonella spp., and B. cereus showed similar seasonality throughout the year, showing a slight increase in the infection rate during the summer months and high prevalence among children under 10 years of age and elder-age people. The antibiotic susceptibility patterns of pathogenic E. coli, Salmonella spp., and S. aureus showed high resistance to penicillins. However, both pathogenic E. coli and Salmonella spp. were susceptible to several cephems, imipenem, and amikacin. Moreover, S. aureus strains resistant to vancomycin were not found. In conclusion, these surveillances can play an important role for the control and prevention to the diseases originated by enteritis bacteria.

Preparation of a nanoporous CaCO3-coated TiO2 electrode and its application to a dye-sensitized solar cell.

A nanoporous CaCO3 overlayer-coated TiO2 thick film was prepared by the topotactic thermal decomposition of Ca(OH)2, and its performance as an electrode of a dye-sensitized solar cell was investigated. As compared to bare TiO2, nanoporous CaCO3-coated TiO2 provided higher specific surface area and, subsequently, a larger amount of dye adsorption; this in turn increased short-circuit current (Jsc). Furthermore, the CaCO3 coating demonstrated increased impedance at the TiO2/dye/electrolyte interface and increased the lifetime of the photoelectrons, indicating the improved retardation of the back electron transfer, which increases Jsc, open-circuit voltage (Voc), and fill factor (ff). Thereby, the energy conversion efficiency (eta) of the solar cell improved from 7.8 to 9.7% (an improvement of 24.4%) as the nanoporous CaCO3 layer was coated onto TiO2 thick films.

Surveillance of bacterial pathogens associated with acute diarrheal disease in the Republic of Korea during one year, 2003.

An epidemiological survey of human enterobacterial infections was conducted to determine the prevalence of enteropathogens in the Republic of Korea during one year, 2003. We tested for infectious diseases in 26,992 stool samples obtained from people who visited clinics located in six big cities and six rural provinces. From these samples, we isolated 1,291 cases of enteritis bacterial infection (4.8%). In the urban areas, 821 cases of bacterial infection (6.4%) were identified and, in the rural areas, 479 bacterial strains (3.3%) were isolated. Seasonal patterns were seen for diarrhea associated with S. aureus, E. coli and V. parahaemolyticus, while Salmonella and Shigella infections showed slight seasonal variation. We found that S. aureus and Salmonella were more frequently isolated from children and the elderly; however, the prevalence of E. coli, V. parahaemolyticus, and Shigella were similar in different age groups. Routine monitoring of these infections is considered a worthwhile means by which to elucidate their epidemiology and modes of transmission and ultimately to control them more effectively. Continuous laboratory-based surveillance for findings of enteritis bacterial infection should be emphasized in the prevention of these infections.

Preparation of nanoporous MgO-coated TiO2 nanoparticles and their application to the electrode of dye-sensitized solar cells.

Sol-gel-derived Mg(OH)(2) gel was coated onto TiO(2) nanoparticles, and the subsequent thermal topotactic decomposition of the gel formed a highly nanoporous MgO crystalline coating. The specific surface area of the electrode that was prepared from the core-shell-structured TiO(2) nanoparticles significantly increased compared with that of the uncoated TiO(2) electrode. The increase in the specific surface area of the MgO-coated TiO(2) electrode was attributed to the highly nanoporous MgO coating layer that resulted from the topotactic reaction. Dye adsorption behavior and solar cell performance were significantly enhanced by employing the MgO-coated TiO(2) electrode. Optimized coating of a MgO layer on TiO(2) nanoparticles enhanced the energy conversion efficiency as much as 45% compared to that of the uncoated TiO(2) electrode. This indicates that controlling the extrinsic parameters such as the specific surface area is very important to improve the energy conversion efficiency of TiO(2)-based solar cells.

In situ observation of the stability of anatase nanoparticles and their transformation to rutile in an acidic solution.

Thermodynamic stability of anatase nanoparticles and their transformation behaviors to rutile phase in an acidic solution was investigated in situ at two different peptization temperatures using a freeze-drying method. When peptized at 30 degrees C, the initial product was anatase with a significantly distorted atomic structure, a significant amount of hydroxyl group and Ti3+ ions, and, thus, a thermodynamically unstable state. The instability of 30 degrees C-peptized anatase was responsible for a suitable transformation to rutile later via dissolution of the anatase to form a titanium hydroxylate, followed by reprecipitation into rutile. On the other hand, 80 degrees C-peptized anatase had a relatively more ordered atomic structure, a much reduced amount of hydroxyl group, negligible Ti3+ ions, and, thus, a thermodynamically more stable state. Plausible reasons why the 80 degrees C-peptized anatase does not transform to rutile were deduced.

Association of Angiotensin-converting enzyme and angiotensinogen gene polymorphisms with preeclampsia.

We tested the hypothesis that angiotensin-converting enzyme (ACE) and angiotensinogen gene polymorphism influence the incidence, development and outcome of preeclampsia. Subjects were recruited from 90 Korean patients with preeclampsia during pregnancy and 98 age-matched controls. After isolation of DNA, polymerase chain reactions (PCR) were carried out to detect polymorphism of the ACE and angiotensinogen. M235T and T174M genotypes of angiotensinogen were determined by digestion with restriction enzyme endonuclease Tth 111-I and NCo I, respectively. The frequency of DD genotype was significantly greater in preeclampsia (0.36) than in controls (0.14) (p<0.05). The frequency of D allele was 0.55 in preeclampsia and 0.40 in controls (p<0.05). There were no differences in the onset of preeclampsia and pregnancy outcomes according to the ACE genotypes. There was no difference in the frequency of a allele of angiotensinogen M235T between the groups (0.79:0.78 in preeclampsia : controls). The frequency of T allele of angiotensinogen T174M gene was slightly increased, but not significantly, in preeclampsia (0.11) than in controls (0.07). In a multivariate analysis, only ACE genotype was associated with the development of preeclampsia (beta=0.27, p=0.05). In conclusion, a molecular variant of ACE, but not angiotensinogen, gene is associated with preeclampsia in Korean women.