Cardiovascular Effects of Binge Drinking Among Korean College Students

Binge drinking is a widespread health problem among young adults. Although Korean college students exhibit a high prevalence of binge drinking, they are not fully aware of the risks of such drinking behavior. Moreover, compared to other populations, they may be more vulnerable to adverse effects of binge drinking on cardiovascular (CV) health due to genetic and cultural factors. However, adverse effects of binge drinking on CV health among Korean college students have scarcely been explored. The purpose of the study was to investigate cardiovascular disease (CVD) risk associated with binge drinking among Korean college students by comparing CVD risk factors (body mass index [BMI] and blood pressure [BP]) and early CVD risk markers (C-reactive protein [hs-CRP], fibrinogen, and triglycerides [TG]) between a binge drinker group and an abstainer group. The study used a non- experimental, comparative, cross-sectional, and quantitative design and a convenience sample of 82 Korean college students aged 18 to 30 years recruited from a university in South Korea. Results of the study indicated that binge drinking may be associated with subclinical CVD and premature risk of CVD. Korean college student binge drinkers had higher TG levels (80 ± 29 mg/dL, z=2.331; p=.020) than abstainers (64 ± 25 mg/dL), and average number of drinks on one occasion was correlated with higher BMI, TG, and 10-year Framingham Risk Score rs=.331, p=.023; rs=.314, p=.030; rs=.301, p=.040, respectively). Therefore, Korean college students should be made aware that repeated binge drinking may increase their risk of developing CVD later in life. Also, Korean healthcare providers should disseminate information about the potential adverse health effects of binge drinking as well as lifestyle strategies for preserving CV health

Nanoscale Structure Dynamics within Electrocatalytic Materials

Electrochemical interfaces used for sensing, (electro)­catalysis, and energy storage are usually nanostructured to expose particular surface sites, but probing the intrinsic activity of these sites is often beyond current experimental capability. Herein, it is demonstrated how a simple meniscus imaging probe of just 30 nm in size can be deployed for direct electrochemical and topographical imaging of electrocatalytic materials at the nanoscale. Spatially resolved topographical and electrochemical data are collected synchronously to create topographical images in which step-height features as small as 2 nm are easily resolved and potential-resolved electrochemical activity movies composed of hundreds of images are obtained in a matter of minutes. The technique has been benchmarked by investigating the hydrogen evolution reaction on molybdenum disulfide, where it is shown that the basal plane possesses uniform activity, while surface defects (i.e., few to multilayer step edges) give rise to a morphology-dependent (i.e., height-dependent) enhancement in catalytic activity. The technique was then used to investigate the electro-oxidation of hydrazine at the surface of electrodeposited Au nanoparticles (AuNPs) supported on glassy carbon, where subnanoentity (i.e., sub-AuNP) reactivity mapping has been demonstrated. We show, for the first time, that electrochemical reaction rates vary significantly across an individual AuNP surface and that these single entities cannot be considered as uniformly active. The work herein provides a road map for future studies in electrochemical science, in which the activity of nanostructured materials can be viewed as <i>quantitative movies</i>, readily obtained, to reveal active sites directly and unambiguously

Simultaneous Topography and Reaction Flux Mapping at and around Electrocatalytic Nanoparticles

The characterization of electrocatalytic reactions at individual nanoparticles (NPs) is presently of considerable interest but very challenging. Herein, we demonstrate how simple-to-fabricate nanopipette probes with diameters of approximately 30 nm can be deployed in a scanning ion conductance microscopy (SICM) platform to simultaneously visualize <i>electrochemical reactivity</i> and <i>topography</i> with high spatial resolution at electrochemical interfaces. By employing a self-referencing hopping mode protocol, whereby the probe is brought from bulk solution to the near-surface at each pixel, and with potential-time control applied at the substrate, current measurements at the nanopipette can be made with high precision and resolution (30 nm resolution, 2600 pixels μm^–2, <0.3 s pixel⁻¹) to reveal a wealth of information on the substrate physicochemical properties. This methodology has been applied to image the electrocatalytic oxidation of borohydride at ensembles of AuNPs on a carbon fiber support in alkaline media, whereby the depletion of hydroxide ions and release of water during the reaction results in a detectable change in the ionic composition around the NPs. Through the use of finite element method simulations, these observations are validated and analyzed to reveal important information on heterogeneities in ion flux between the top of a NP and the gap at the NP-support contact, diffusional overlap and competition for reactant between neighboring NPs, and differences in NP activity. These studies highlight key issues that influence the behavior of NP assemblies at the single NP level and provide a platform for the use of SICM as an important tool for electrocatalysis studies

Hierarchically Driven IrO₂ Nanowire Electrocatalysts for Direct Sensing of Biomolecules

Applying nanoscale device fabrications toward biomolecules, ultra sensitive, selective, robust, and reliable chemical or biological microsensors have been one of the most fascinating research directions in our life science. Here we introduce hierarchically driven iridium dioxide (IrO₂) nanowires directly on a platinum (Pt) microwire, which allows a simple fabrication of the amperometric sensor and shows a favorable electronic property desired for sensing of hydrogen peroxide (H₂O₂) and dihydronicotinamide adenine dinucleotide (NADH) without the aid of enzymes. This rational engineering of a nanoscale architecture based on the direct formation of the hierarchical 1-dimensional (1-D) nanostructures on an electrode can offer a useful platform for high-performance electrochemical biosensors, enabling the efficient, ultrasensitive detection of biologically important molecules

Mobility and Poisoning of Mass-Selected Platinum Nanoclusters during the Oxygen Reduction Reaction

A major challenge in electrocatalysis is to understand the effect of electrochemical processes on the physicochemical properties of nanoparticle or nanocluster (NC) ensembles, especially for complex processes, such as the oxygen reduction reaction (ORR) considered herein. We describe an approach whereby electrocatalysis at a small number of well-defined mass-selected Pt NCs (Pt_923±37, diameter, <i>d</i> ≈ 3 nm), deposited from a cluster beam source on carbon-coated transmission electron microscopy (TEM) grids, can be measured by a scanning electrochemical cell microscopy (SECCM) setup, in tandem with a range of complementary microscopy and spectroscopy techniques. The SECCM setup delivers high mass transport rates and allows the effects of transient reactive intermediates to be elucidated for different Pt surface coverages (NC spacing). A major observation is that the ORR activity decreases during successive electrochemical (voltammetric) measurements. This is shown to be due to poisoning of the Pt NCs by carbon-/oxygen-containing moieties that are produced by the reaction of reactive oxygen intermediates (RIs), generated by the ORR, with the carbon support. The effect is most prominent when the Pt surface coverage on the carbon support is low (<6%). Furthermore, the NC deposition impact energy drastically affects the resulting Pt NC stability during electrochemistry. For lower impact energy, Pt NCs migrate as a consequence of the ORR and are rearranged into characteristic groups on the support. This previously unseen effect is caused by an uneven flux distribution around individual NCs within the ensemble and has important consequences for understanding the stability and activity of NC and nanoparticle arrays

Growth of Highly Single Crystalline IrO₂ Nanowires and Their Electrochemical Applications

We present the facile growth of highly single crystalline iridium dioxide (IrO₂) nanowires on SiO₂/Si and Au substrates via a simple vapor phase transport process under atmospheric pressure without any catalyst. Particularly, high-density needle-like IrO₂ nanowires were readily obtained on a single Au microwire, suggesting that the melted surface layer of Au might effectively enhance the nucleation of gaseous IrO₃ precursors at the growth temperature. In addition, all the electrochemical observations of the directly grown IrO₂ nanowires on a single Au microwire support favorable electron-transfer kinetics of [Fe­(CN₆)]^4–/3– as well as Ru­(NH₃)₆^3+/2+ at the highly oriented crystalline IrO₂ nanowire surface. Furthermore, stable pH response is shown, revealing potential for use as a miniaturized pH sensor, confirmed by the calibration curve exhibiting super-Nernstian behavior with a slope of 71.6 mV pH^–1

Highly Efficient Electrochemical Responses on Single Crystalline Ruthenium–Vanadium Mixed Metal Oxide Nanowires

Highly efficient single crystalline ruthenium–vanadium mixed metal oxide (Ru_1–<i>x</i>V_<i>x</i>O₂, 0 ≤ <i>x</i> ≤ 1) nanowires were prepared on a SiO₂ substrate and a commercial Au microelectrode for the first time through a vapor-phase transport process by adjusting the mixing ratios of RuO₂ and VO₂ precursors. Single crystalline Ru_1–<i>x</i>V_<i>x</i>O₂ nanowires show homogeneous solid-solution characteristics as well as the distinct feature of having remarkably narrow dimensional distributions. The electrochemical observations of a Ru_1–<i>x</i>V_<i>x</i>O₂ (<i>x</i> = 0.28 and 0.66)-decorated Au microelectrode using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrate favorable charge-transfer kinetics of [Fe­(CN)₆]^3–/4– and Ru­(NH₃)₆^3+/2+ couples compared to that of a bare Au microelectrode. The catalytic activity of Ru_1–<i>x</i>V_<i>x</i>O₂ for oxygen and H₂O₂ reduction at neutral pH increases as the fraction of vanadium increases within our experimental conditions, which might be useful in the area of biofuel cells and biosensors

Correlations between Transmembrane 4 L6 Family Member 5 (TM4SF5), CD151, and CD63 in Liver Fibrotic Phenotypes and Hepatic Migration and Invasive Capacities

<div><p>Transmembrane 4 L6 family member 5 (TM4SF5) is overexpressed during CCl₄-mediated murine liver fibrosis and in human hepatocellular carcinomas. The tetraspanins form tetraspanin-enriched microdomains (TEMs) consisting of large membrane protein complexes on the cell surface. Thus, TM4SF5 may be involved in the signal coordination that controls liver malignancy. We investigated the relationship between TM4SF5-positive TEMs with liver fibrosis and tumorigenesis, using normal Chang hepatocytes that lack TM4SF5 expression and chronically TGFβ1-treated Chang cells that express TM4SF5. TM4SF5 expression is positively correlated with tumorigenic CD151 expression, but is negatively correlated with tumor-suppressive CD63 expression in mouse fibrotic and human hepatic carcinoma tissues, indicating cooperative roles of the tetraspanins in liver malignancies. Although CD151 did not control the expression of TM4SF5, TM4SF5 appeared to control the expression levels of CD151 and CD63. TM4SF5 interacted with CD151, and caused the internalization of CD63 from the cell surface into late lysosomal membranes, presumably leading to terminating the tumor-suppressive functions of CD63. TM4SF5 could overcome the tumorigenic effects of CD151, especially cell migration and extracellular matrix (ECM)-degradation. Taken together, TM4SF5 appears to play a role in liver malignancy by controlling the levels of tetraspanins on the cell surface, and could provide a promising therapeutic target for the treatment of liver malignancies.</p></div

The relationships of TM4SF5, CD151, and CD63 in the development of murine liver fibrosis and liver cancer.

<p>(A to D) Liver tissues from mice administrated with control vehicle or CCl₄ every other day for 2 weeks were used for RT-PCR analysis (A), harvested for whole extracts, prior to Western blots for the indicated proteins (B), used for Masson’s trichrome staining to determine collagen I expression (C), or processed for immunohistochemistry with double-staining for TM4SF5 and CD151 (D). (E) Human normal or liver tumor tissues were processed for Western blots or immunohistochemistry to identify CD151 (top), TM4SF5 (middle), and CD63 (bottom) and the nuclei were stained using DAPI. Scale bars depict 10 µm. Data represent three independent experiments.</p

Different collaborative effects of TM4SF5, CD151, and CD63 on migration and invasive ECM degradation.

<p>Transwell migration analyses (A to D) or ECM-degradation analyses (E to H) were performed using Chang-TGFβ1 cells transfected with the indicated shRNAs or plasmids. (A to D) The bottom chamber was filled with 10% FBS/DMEM-H. After 18 h, cells migrated to the bottom surface of the filter were stained and imaged. Representative images (at least 5 images) were counted to determine migration in each experimental condition. Mean ± standard deviation were graphed (A to C), and representative images of (C) were shown (D). (E to H) Chang-TGFβ1 cells transfected with shRNA or plasmids were reseeded onto coverslips precoated with Oregon Green 488-conjugated gelatin and incubated for 18 h in a CO₂ incubator. The dark-spotted ECM-degraded areas from more than 5 random images were counted for graphic presentations using mean ± standard deviation. Representative images in (H) are shown (G). * or ** depict <i>P</i> values less than 0.001 or 0.05 for statistical significance, respectively, whereas *** depicts <i>P</i> values greater than 0.05 for insignificance, and numbers in (B) represent the <i>P</i> values by Student’s <i>t</i>-tests. Data represent three independent experiments.</p