High-performance, transparent, and stretchable electrodes using graphene-metal nanowire hybrid structures.

Transparent electrodes that can remain electrically conductive and stable under large mechanical deformations are highly desirable for applications in flexible and wearable electronics. This paper describes a comprehensive study of the electrical, optical, and mechanical properties of hybrid nanostructures based on two-dimensional graphene and networks of one-dimensional metal nanowires, and their use as transparent and stretchable electrodes. Low sheet resistance (33 Ω/sq) with high transmittance (94% in visible range), robust stability against electric breakdown and oxidation, and superb flexibility (27% in bending strain) and stretchability (100% in tensile strain) are observed, and these multiple functionalities of the hybrid structures suggest a future promise for next generation electronics. The use of hybrid electrodes to fabricate oxide semiconductor transistors and single-pixel displays integrated on wearable soft contact lenses with in vivo tests are demonstrated.

Impact of reduced vancomycin MIC on clinical outcomes of methicillin-resistant Staphylococcus aureus bacteremia.

Vancomycin has been a key antibiotic agent for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. However, little is known about the relationship between vancomycin MIC values at the higher end of the susceptibility range and clinical outcomes. The aim of this study was to determine the impact of MRSA bacteremia on clinical outcomes in patients with a vancomycin MIC near the upper limit of the susceptible range. Patients with MRSA bacteremia were divided into a high-vancomycin-MIC group (2 µg/ml) and a low-vancomycin-MIC group (≤1.0 µg/ml). We examined the relationship between MIC, genotype, primary source of bacteremia, and mortality. Ninety-four patients with MRSA bacteremia, including 31 with a high vancomycin MIC and 63 with a low MIC were analyzed. There was no significant difference between the presence of agr dysfunction and SCCmec type between the two groups. A higher vancomycin MIC was not found to be associated with mortality. In contrast, high-risk bloodstream infection sources (hazard ratio [HR], 4.63; 95% confidence interval [CI] = 1.24 to 17.33) and bacterial eradication after treatment (HR, 0.06; 95% CI = 0.02 to 0.17), irrespective of vancomycin MIC, were predictors of all-cause 30-day mortality. Our study suggests that a high-risk source of bacteremia is likely to be associated with unfavorable clinical outcomes, but a high vancomycin MIC in a susceptible range, as well as genotype characteristics, are not associated with mortality.

A Study on the Factors Influencing Smoking in Multicultural Youths in Korea.

Based on the ecological integration model, this study examined the factors affecting smoking in adolescents from multicultural families by dividing them into two levels: microsystem and social network factors. The data were from the Korea Youth Risk Behavior Web-Based Survey (KYRBS) from 2016 to 2020. It included 4577 respondents whose fathers, mothers, or both, were not born in Korea. The factors affecting smoking among multicultural teenagers were determined by a composite-sample multiple logistic regression analysis. Male smoking rates among multicultural adolescents were 2.49 times higher than female rates in the microsystem. When the father was "Korean" rather than a "Foreigner", smoking was 0.55 times lower in family factors in terms of social network. In social factors of social networks, multicultural adolescents' smoking was 12.02 times greater when they were drinking than when they were not, and 3.62 times higher when the answer to the question of whether they had experienced violence was "yes" than "no." Based on the ecological model in this study, social factors such as drinking, and violence were highly related to smoking. Since multicultural adolescents were closely influenced by the surrounding environment, such as family, school, and social relationship, it was necessary to let parents and schoolteachers be involved in the intervention of smoking of multicultural adolescents so that they can help multicultural adolescents adjust better to school and perform better academically while decreasing risky behaviors for their health, such as drinking and, ultimately, smoking.

Septic shock due to Vibrio alginolyticus in a cirrhotic patient: the first case in Korea.

We describe a case of septic shock due to Vibrio alginolyticus presenting with fever and bilateral leg pain. Despite intensive management with antibiotics and inotropic agents, the patient died from septic shock 1 day after hospitalization. V. alginolyticus was isolated from both leg wounds and a blood culture. To the best of our knowledge, this is the first reported case of V. alginolyticus bacteremia in Korea.

Selective inhibition of cell growth by activin in SNU-16 cells.

AIM: To investigate whether activin regulates the cell proliferation of human gastric cancer cell line SNU-16 through the mRNA changes in activin receptors, Smads and p21(CIP1/WAF1). METHODS: The human gastric cancer cell lines were cultured, RNAs were purified, and RT-PCRs were carried out with specifically designed primer for each gene. Among them, the two cell lines SNU-5 and SNU-16 were cultured with activin A for 24, 48 and 72 h. The cell proliferation was measured by MTT assay. For SNU-16, changes in ActRIA, ActRIB, ActRIIA, ActRIIB, Smad2, Smad4, Smad7, and p21(CIP1/WAF1) mRNAs were detected with RT-PCR after the cells were cultured with activin A for 24, 48 and 72 h. RESULTS: The proliferation of SNU-16 cells was down regulated by activin A whereas other cells showed no change. Basal level of inhibin/activin subunits, activin receptors, Smads, and p21(CIP1/WAF1) except for activin betaB mRNAs was observed to have differential expression patterns in the human gastric cancer cell lines, AGS, KATO III, SNU-1, SNU-5, SNU-16, SNU-484, SNU-601, SNU-638, SNU-668, and SNU-719. Interestingly, significantly higher expressions of ActR IIA and IIB mRNAs were observed in SNU-16 cells when compared to other cells. After activin treatment, ActR IA, IB, and IIA mRNA levels were decreased whereas ActR IIB mRNA level increased in SNU-16 cells. Smad4 mRNA increased for up to 48 h whereas Smad7 mRNA increased sharply at 24 h and returned to the initial level at 48 h in SNU-16 cells. In addition, expression of the p21(CIP1/WAF1), the mitotic inhibitor, peaked at 72 h after activin treatment in SNU-16 cells. CONCLUSION: Our results suggest that inhibition of cell growth by activin is regulated by the negative feedback effect of Smad7 on the activin signaling pathway, and is mediated through p21(CIP1/WAF1) activation in SNU-16 cells.

High-Resolution Printing of 3D Structures Using an Electrohydrodynamic Inkjet with Multiple Functional Inks.

Electrohydrodynamic-inkjet-printed high-resolution complex 3D structures with multiple functional inks are demonstrated. Printed 3D structures can have a variety of fine patterns, such as vertical or helix-shaped pillars and straight or rounded walls, with high aspect ratios (greater than ≈50) and narrow diameters (≈0.7 µm). Furthermore, the formation of freestanding, bridge-like Ag wire structures on plastic substrates suggests substantial potentials as high-precision, flexible 3D interconnects.

Temporal changes in cerebral antioxidant enzyme activities after ischemia and reperfusion in a rat focal brain ischemia model: effect of dietary fish oil.

This study investigated the neuroprotective effects of dietary supplementation of fish oil on both brain infarction and the activities of antioxidant enzymes. Male Sprague-Dawley rats (4-weeks old) were divided into two groups and received either a regular diet (RD) or a fish-oil-supplemented diet (FOD) for 6 weeks prior to middle cerebral artery (MCA) occlusion. The infarction volume of the brain was calculated using image analysis after staining. Antioxidant enzymes were measured before ischemia (BI), after 2 h of ischemia (AI) and after 24 h (24hR), 48 h (48hR) and after 7 days (7dR) of reperfusion. The infarction volume of the brain was significantly smaller in the FOD group than in the RD group after 24 h of reperfusion (p<0.05). Before ischemia, the levels of lipid peroxide and the glutathione peroxidase (GPx) activity were higher in the FOD group than in the RD group. During reperfusion, the catalase (CAT) activity in the FOD group remained at the preischemia level until after 48 h of reperfusion, while those in the RD group did not. The Mn-superoxide dismutase (SOD) activity and GPx activity were higher in the FOD group than in the RD group only after 2 h of ischemia. In the fatty acid analysis, the ratio of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were higher in the FOD group than in the RD group (p<0.05). Our results demonstrate that supplementing the diet with fish oil could decrease the cerebral infarction volume following ischemia and reperfusion (I/R) partly by working directly as an antioxidant and partly by modulating antioxidant enzyme activities.

Identification of strain harboring both aac(6')-Ib and aac(6')-Ib-cr variant simultaneously in Escherichia coli and Klebsiella pneumoniae.

The aac(6')-Ib gene is the most prevalent gene that encodes aminoglycoside-modifying enzymes and confers resistance to tobramycin, kanamycin, and amikacin. The aac(6')-Ib-cr variant gene can induce resistance against aminoglycoside and fluoroquinolone simultaneously. Two main methods, sequence analysis and the restriction enzyme method, can detect the aac(6')-Ib-cr variant in clinical strains. We collected the 85 strains that were believed to be aac(6')-Ib positive from clinical isolates. Among them, 38 strains were the wild-type; the remaining 47 strains were the aac(6')-Ib-cr variant. Of these 47 strains, 19 simultaneously harbored aac(6')-Ib and aac(6')-Ib-cr. Our study aims to report the characteristics of the 19 strains that simultaneously harbored both genes. This study is the first investigation published in Korea of strains that included both aac(6')-Ib and aac(6')-Ib-cr variant.

Evaluation of commercial selective agars in screening for methicillin-resistant Staphylococcus aureus.

To evaluate methicillin-resistant S. aureus (MRSA) detection methods, we compared (a) mannitol salt agar with cefoxitin (MSA-FX), (b) MRSASelect agar (Bio-Rad), (c) MRSA ID (bioMerieuex), and (d) CHROMagar MRSA (BD Diagnostics) as selective media for culturing nasal swab specimens collected from intensive care unit (ICU) patients and healthcare personnel. A total of 99 (17.1%) cases of MRSA were recovered from 578 specimens. Four (5.5%) cases were identified from healthcare personnel and 95 (18.8%) were from ICU patients. The sensitivity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 83.8, 87.9, 80.8, and 84.8% after 18 hr; 92.9, 94.9, 90.9, and 91.9% after 24 hr; and 96.0, 100, 99.0, and 99.0% after 48 hr, respectively. The specificity of MSA-FX, MRSASelect, MRSA ID, and CHROMagar MRSA was 97.7, 99.0, 98.7. and 99.8% after 18 hr; 97.1, 98.5, 98.1, and 99.5% after 24 hr; and 95.2, 97.7, 97.9, and 99.0% after 48 hr, respectively. In conclusion, all four media showed good results after the 24 hr readings, but MRSA ID and CHROMagar MRSA media required readings at 48 hr due to increased sensitivity at this time point.

Molecular characteristics of methicillin-resistant Staphylococcus aureus blood isolates: clonal spread of staphylococcal cassette chromosome mec type IVA between the community and the hospital.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is becoming increasingly common worldwide. The purpose of this study was to identify the prevalence and molecular characteristics of MRSA bloodstream isolates in hospitals. Clinical data from patients with MRSA bacteremia between 2003 and 2005 were collected. Isolates were classified as hospital-acquired (HA-MRSA), health care-associated (HCA-MRSA), or CA-MRSA according to the time of isolation and the risk factors for colonization. Available strains were tested for the presence of mecA, staphylococcal cassette chromosome mec (SCCmec), and by multilocus sequence test. Among 129 cases, 78 nonduplicated isolates were analyzed. The proportion of CA-MRSA, HCA-MRSA, and HA-MRSA was 2.6% (2), 23.1% (18), and 74.4% (58), respectively. According to multilocus sequence test and SCCmec, there were seven genotypes with sequence types (STs) and SCCmec types. The predominant genotype, ST5-MRSA-II, was found in 57.7% (45). All type IVA isolates was ST72 (9), and ST72-MRSA-IVA was identified in CA-MRSA (2, 100%), HCA-MRSA (1, 5.6%), and HA-MRSA (6, 10.3%), respectively. In summary, CA-MRSA bacteremia was not common in our hospital during the period.

Susceptibility and trailing growth of Candida albicans to fluconazole: results of a Korean multicentre study.

The work reported here is the first nationwide, multicenter surveillance study conducted in Korea to obtain data on fluconazole susceptibility of Candida albicans (C. albicans) isolates. A total of 1137 isolates of C. albicans obtained from 17 university hospitals in South Korea during the 6-month period, July through December 2004, were tested. No resistant strains were observed in any of the isolates. Only five of the 1137 isolates (0.44%) of C. albicans were found to be susceptible dose dependent, with all remaining strains (99.56%) susceptible to fluconazole. Trailing growth at 48 h was found in only four isolates (0.35%).

Clinical usefulness of free light chain concentration as a tumor marker in multiple myeloma.

Monoclonal immunoglobulin, as a marker for monoclonal gammopathy, is evaluated by protein electrophoresis (PEP) and immunofixation electrophoresis (IFE). However, PEP and IFE are not satisfactory in sensitivity, objectivity, and facility. Recently, a highly sensitive, automated immunoassay for measurement of free light chain (FLC) concentrations in serum and urine has been developed for the identification and monitoring of patients with monoclonal gammopathy. To explore the clinical usefulness of measurement of FLC concentrations, we measured the kappa and lambda FLC concentrations and calculated the kappa/lambda FLC ratios for three groups [multiple myeloma (MM), other diseases, and control] and compared the results of the FLC assay with the results of PEP or IFE. The concentrations of serum kappa and lambda FLCs and the kappa/lambda FLC ratios for the MM group and non-MM groups were distinct. In the MM group, some sera and urine samples had no evidence of M protein on PEP and IFE, but FLC assay showed abnormal concentrations of FLCs and abnormal kappa/lambda FLC ratios in most cases. As compared with the PEP, the kappa/lambda FLC ratio revealed higher sensitivity in all diagnostic ranges with different cutoff values. Particularly, when the cutoff value 2.0 for kappa/lambda FLC ratio was used, specificity and positive predictive value were largely improved than when the cutoff values 1.2 and 1.5 were used. These findings indicated that FLC assay enables to detect myeloma patients with very low M protein due to early stage or after therapy and to distinguish patients with monoclonal increase of FLC from patients with polyclonal increase of FLC due to other conditions, particularly using kappa/lambda FLC ratio 0.3-2.0 as a diagnostic range. Despite some technical limitations of the assay, the incorporation of kappa/lambda FLC ratios with FLC concentrations is useful in the detection of M protein, particularly with negative serum or urine IFE results, and differentiation of monoclonal gammopathies from patients with polyclonal increase in FLC due to other conditions.

Increasing prevalence of vancomycin-resistant Enterococcus faecium, expanded-spectrum cephalosporin-resistant Klebsiella pneumoniae, and imipenem-resistant Pseudomonas aeruginosa in Korea: KONSAR study in 2001.

The 5th year KONSAR surveillance in 2001 was based on routine test data at 30 participating hospitals. It was of particular interest to find a trend in the resistances of enterococci to vancomycin, of Enterobacteriaceae to the 3rd generation cephalosporin and fluoroquinolone, and of Pseudomonas aeruginosa and acinetobacters to carbapenem. Resistance rates of Gram-positive cocci were: 70% of Staphylococcus aureus to oxacillin; 88% and 16% of Enterococcus faecium to ampicillin and vancomycin, respectively. Seventy-two percent of pneumococci were nonsusceptible to penicillin. The resistance rates of Enterobacteriaceae were: Escherichia coli, 28% to fluoroquinolone; Klebsiella pneumoniae, 27% to ceftazidime, and 20% to cefoxitin; and Enterobacter cloacae, > or =40% to cefotaxime and ceftazidime. The resistance rates of P. aeruginosa were 21% to ceftazidime, 17% to imipenem, and those of the acinetobacters were > or =61% to ceftazidime, aminoglycosides, fluoroquinolone and cotrimoxazole. Thirty-five percent of non-typhoidal salmonellae were ampicillin resistant, and 66% of Haemophilus influenzae were beta-lactamase producers. Notable changes over the 1997-2001 period were: increases in vancomycin-resistant E. faecium, and amikacin- and fluoroquinolone-resistant acinetobacters. With the increasing prevalence of resistant bacteria, nationwide surveillance has become more important for optimal patient management, for the control of nosocomial infection, and for the conservation of the newer antimicrobial agents.