An Aqueous Process for Preparing Flexible Transparent Electrodes Using Non-Oxidized Graphene/Single-Walled Carbon Nanotube Hybrid Solution.

In this study, we prepared flexible and transparent hybrid electrodes based on an aqueous solution of non-oxidized graphene and single-walled carbon nanotubes. We used a simple halogen intercalation method to obtain high-quality graphene flakes without a redox process and prepared hybrid films using aqueous solutions of graphene, single-walled carbon nanotubes, and sodium dodecyl sulfate surfactant. The hybrid films showed excellent electrode properties, such as an optical transmittance of ≥90%, a sheet resistance of ~3.5 kΩ/sq., a flexibility of up to ε = 3.6% ((R) = 1.4 mm), and a high mechanical stability, even after 103 bending cycles at ε = 2.0% ((R) = 2.5 mm). Using the hybrid electrodes, thin-film transistors (TFTs) were fabricated, which exhibited an electron mobility of ~6.7 cm2 V-1 s-1, a current on-off ratio of ~1.04 × 107, and a subthreshold voltage of ~0.122 V/decade. These electrical properties are comparable with those of TFTs fabricated using Al electrodes. This suggests the possibility of customizing flexible transparent electrodes within a carbon nanomaterial system.

Ultrastrong Hybrid Fibers with Tunable Macromolecular Interfaces of Graphene Oxide and Carbon Nanotube for Multifunctional Applications.

Individual carbon nanotubes (CNT) and graphene have unique mechanical and electrical properties; however, the properties of their macroscopic assemblies have not met expectations because of limited physical dimensions, the limited degree of dispersion of the components, and various structural defects. Here, a state-of-the-art assembly for a novel type of hybrid fiber possessing the properties required for a wide variety of multifunctional applications is presented. A simple and effective multidimensional nanostructure of CNT and graphene oxide (GO) assembled by solution processing improves the interfacial utilization of the components. Flexible GOs are effectively intercalated between nanotubes along the shape of CNTs, which reduces voids, enhances orientation, and maximizes the contact between elements. The microstructure is finely controlled by the elements content ratio and dimensions, and an optimal balance improves the mechanical properties. The hybrid fibers simultaneously exhibit exceptional strength (6.05 GPa), modulus (422 GPa), toughness (76.8 J g-1 ), electrical conductivity (8.43 MS m-1 ), and knot strength efficiency (92%). Furthermore, surface and electrochemical properties are significantly improved by tuning the GO content, further expanding the scope of applications. These hybrid fibers are expected to offer a strategy for overcoming the limitations of existing fibers in meeting the requirements for applications in the fiber industry.

Analysis of the Factors Influencing Body Weight Variation in Hanwoo Steers Using an Automated Weighing System.

This study aimed to determine the factors affecting the body weight (BW) of Hanwoo steers by collecting a large number of BW measurements using an automated weighing system (AWS). The BW of 12 Hanwoo steers was measured automatically using an AWS for seven days each month over three months. On the fourth day of the BW measurement each month, an additional BW measurement was conducted manually. After removing the outliers of BW records, the deviations between the AWS records (a) and manual weighing records (b) were analyzed. BW measurement deviations (a - b) were significantly (p < 0.05) affected by month, day and the time within a day as well as the individual animal factor; however, unexplained random variations had the greatest impact (70.4%). Excluding unexplained random variations, the difference between individual steers was the most influential (80.1%). During the day, the BW of Hanwoo steers increased before feed offerings and significantly decreased immediately after (p < 0.05), despite the constant availability of feeds in the feed bunk. These results suggest that there is a need to develop pattern recognition algorithms that consider variations in individual animals and their feeding patterns for the analysis of BW changes in animals.

Risk assessment of zinc oxide, a cosmetic ingredient used as a UV filter of sunscreens.

Zinc oxide (ZnO), an inorganic compound that appears as a white powder, is used frequently as an ingredient in sunscreens. The aim of this review was to examine the toxicology and risk assessment of ZnO based upon available published data. Recent studies on acute, sub-acute, and chronic toxicities of ZnO indicated that this compound is virtually non-toxic in animal models. However, it was reported that ZnO nanoparticles (NP) (particle size, 40 nm) induced significant changes in anemia-related hematologic parameters and mild to moderate pancreatitis in male and female Sprague-Dawley rats at 536.8 mg/kg/day in a 13-week oral toxicity study. ZnO displayed no carcinogenic potential, and skin penetration is low. No-observed-adverse-effect level (NOAEL) ZnO was determined to be 268.4 mg/kg/day in a 13-week oral toxicity study, and a maximum systemic exposure dose (SED) of ZnO was estimated to be 0.6 mg/kg/day based on topical application of sunscreen containing ZnO. Subsequently, the lowest margin of safety (MOS) was estimated to be 448.2, which indicates that the use of ZnO in sunscreen is safe. A risk assessment was undertaken considering other routes of exposure (inhalation or oral) and major product types (cream, lotion, spray, and propellant). Human data revealed that MOS values (7.37 for skin exposure from cream and lotion type; 8.64 for skin exposure of spray type; 12.87 for inhalation exposure of propellant type; 3.32 for oral exposure of sunscreen) are all within the safe range (MOS > 1). Risk assessment of ZnO indicates that this compound may be used safely in cosmetic products within the current regulatory limits of 25% in Korea.

Dietary hydroxycinnamates prevent oxidative damages to liver, spleen, and bone marrow cells in irradiation-exposed mice.

Dietary hydroxycinnamates are considered as attractive materials for radioprotection. This study explores whether hydroxycinnamates protect against γ-radiation-induced cellular damages and hematopoietic stem cell senescence. C57BL/6 mice were orally administered with each of caffeic acid, p-coumaric acid, and ferulic acid (20mg/kg body weight) once per three days for five times before exposure to total body radiation (5 Gy). Irradiation increased the activities of alanine amino transaminase and aspartate aminotransferase in blood serum but decreased the anti-oxidant defense enzyme activities in the liver and spleen tissues. Oral administration of the compounds almost completely prevented irradiation-mediated changes in these enzyme activities. The hydroxycinnamates also inhibited the irradiation-mediated increases in the mitochondrial superoxide anions of Lin-Sca-1+c-Kit+ (LSK) cells and CD150+CD48- LSK cells in the bone marrow. These results suggest that dietary hydroxycinnamates protect against irradiation-mediated oxidative damages of tissues and bone marrow progenitor cells.

Intestinal anti-inflammatory activity of the seeds of Raphanus sativus L. in experimental ulcerative colitis models.

ETHNOPHARMACOLOGICAL RELEVANCE: Water extract of Raphanus sativus L. (RSL) seeds was traditionally used to treat digestive inflammatory complaints in Korean culture. RSL seeds exerted antioxidant, anti-inflammatory, and anti-septic functions, suggesting their pharmacological potential for the treatment of inflammatory pathologies associated with oxidative stress such as inflammatory bowel disease. AIM OF THIS STUDY: We evaluated the intestinal anti-inflammatory effects of RSL seed water extract (RWE) in experimental rat models of trinitrobenzenesulphonic acid (TNBS)- or dextran sodium sulfate (DSS)-induced colitis. MATERIALS AND METHODS: RWE was characterized by determining the content of sinapic acid as a reference material and then assayed in the DSS and TNBS models of rat colitis. Male Sprague-Dawley rats were divided into 10 groups (n=7/group): non-colitic control, DSS or TNBS control, DSS colitis groups treated with RWE (100mg/kg) or mesalazine (25mg/kg), and TNBS colitis groups treated with various doses (10, 40, 70, and 100mg/kg) of RWE or mesalazine (25mg/kg). RWE or mesalazine treatment started the same day of colitis induction and rats were sacrificed 24h after the last treatment followed by histological and biochemical analyses. RESULTS: Oral administration with RWE suppressed intestinal inflammatory damages in both DSS- and TNBS-induced colitic rats. The treatment with 100mg/kg RWE recovered intestinal damages caused by TNBS or DSS to levels similar to that of mesalazine, decreasing the activity of myeloperoxidase activity and the secretion of tumor necrosis factor (TNF)-α and interleukin (IL)-1ß. RWE treatment inhibited malondialdehyde production and glutathione reduction in colon of colitis rats. The administration of RWE at dose of 100mg/kg also suppressed the TNBS- or DSS-stimulated expression of TNF-α, IL-1ß, monocyte chemotactic protein-1, inducible nitric oxide, and intercellular adhesion molecule-1. Furthermore, RWE inhibited p38 kinase and DNA-nuclear factor-κB binding activities, both of which were stimulated in the colitic rats. CONCLUSIONS: The current findings show that RWE ameliorates intestinal oxidative and inflammatory damages in DSS and TNBS models of rat colitis, suggesting its beneficial use for the treatment of intestinal inflammatory disorders.

Ovarian function preservation with GnRH agonist in young breast cancer patients: does it impede the effect of adjuvant chemotherapy?

BACKGROUND: Concurrent endocrine therapy with chemotherapy had a concern of potential antagonism. However, gonadotropin-releasing hormone (GnRH) agonist has been used concurrently with chemotherapy to prevent premature ovarian failure for young breast cancer patients. The aim of this study was to determine the impact of concurrent use of GnRH agonists on relapse-free and overall survival, and to establish the oncologic safety of ovarian protection with GnRH agonists. METHODS: Premenopausal women aged between 20 and 40 years who received adjuvant chemotherapy for breast cancer from January 2002 to April 2012 were classified into two groups; One treated with GnRH agonists for ovarian protection during chemotherapy, and the other without ovarian protection. A propensity score matching strategy was used to create matched sets of two groups with age, pathologic stage, hormone receptor, and Her2 status. RESULTS: A total of 101 patients treated with concurrent GnRH agonist during chemotherapy were compared with 335 propensity score matched patients. Among them, 81.2% were younger than 35 years and 58.4% were hormone responsive. Survival analysis using stratified Cox regression showed that women treated with concurrent GnRH agonists had better recurrence-free survival (adjusted Hazard ratio 0.21, p = 0.009; unadjusted Hazard ratio 0.33, p = 0.034). CONCLUSIONS: Ovarian protection using GnRH agonists can be safely considered for young women with breast cancer in terms of oncologic outcomes. Further studies are needed to assess the long-term outcomes of concurrent GnRH agonist use with chemotherapy.

Opening and reversible control of a wide energy gap in uniform monolayer graphene.

For graphene to be used in semiconductor applications, a 'wide energy gap' of at least 0.5 eV at the Dirac energy must be opened without the introduction of atomic defects. However, such a wide energy gap has not been realized in graphene, except in the cases of narrow, chemically terminated graphene nanostructures with inevitable edge defects. Here, we demonstrated that a wide energy gap of 0.74 eV, which is larger than that of germanium, could be opened in uniform monolayer graphene without the introduction of atomic defects into graphene. The wide energy gap was opened through the adsorption of self-assembled twisted sodium nanostrips. Furthermore, the energy gap was reversibly controllable through the alternate adsorption of sodium and oxygen. The opening of such a wide energy gap with minimal degradation of mobility could improve the applicability of graphene in semiconductor devices, which would result in a major advancement in graphene technology.

Monitoring of vegetation impact due to trampling on Cadillac Mountain summit using high spatial resolution remote sensing data sets.

Cadillac Mountain--the highest peak along the eastern seaboard of the United States--is a major tourist destination in Acadia National Park, Maine. Managing vegetation impact due to trampling on the Cadillac Mountain summit is extremely challenging because of the large number of visitors and the general open nature of landscape in this fragile subalpine environmental setting. Since 2000, more intensive management strategies--based on placing physical barriers and educational messages for visitors--have been employed to protect threatened vegetation, decrease vegetation impact, and enhance vegetation recovery in the vicinity of the summit loop trail. The primary purpose of this study was to evaluate the effect of the management strategies employed. For this purpose, vegetation cover changes between 2001 and 2007 were detected using multispectral high spatial resolution remote sensing data sets. A normalized difference vegetation index was employed to identify the rates of increase and decrease in the vegetation areas. Three buffering distances (30, 60, and 90 m) from the edges of the trail were used to define multiple spatial extents of the site, and the same spatial extents were employed at a nearby control site that had no visitors. No significant differences were detected between the mean rates of vegetation increase and decrease at the experimental site compared with a nearby control site in the case of a small spatial scale (≤30 m) comparison (in all cases P > 0.05). However, in the medium (≤60 m) and large (≤90 m) spatial scales, the rates of increased vegetation were significantly greater and rates of decreased vegetation significantly lower at the experimental site compared with the control site (in all cases P < 0.001). Research implications are explored that relate to the spatial extent of the radial patterns of impact of trampling on vegetation at the site level. Management implications are explored in terms of the spatial strategies used to decrease the impact of trampling on vegetation.

Anomalous behaviors of visible luminescence from graphene quantum dots: interplay between size and shape.

For the application of graphene quantum dots (GQDs) to optoelectronic nanodevices, it is of critical importance to understand the mechanisms which result in novel phenomena of their light absorption/emission. Here, we present size-dependent shape/edge-state variations of GQDs and visible photoluminescence (PL) showing anomalous size dependences. With varying the average size (d(a)) of GQDs from 5 to 35 nm, the peak energy of the absorption spectra monotonically decreases, while that of the visible PL spectra unusually shows nonmonotonic behaviors having a minimum at d(a) = ~17 nm. The PL behaviors can be attributed to the novel feature of GQDs, that is, the circular-to-polygonal-shape and corresponding edge-state variations of GQDs at d(a) = ~17 nm as the GQD size increases, as demonstrated by high-resolution transmission electron microscopy.

Identification of a peptide that interacts with Nestin protein expressed in brain cancer stem cells.

Glioma stem cells (GSCs) are presumably major culprits for brain tumor initiation, progression, and recurrence after conventional therapies. Thus, selective targeting and eradication of GSCs may provide a promising and effective therapeutic approach. Here, we isolated a GSC-targeting (GSCT) peptide that demonstrated selective binding affinity for many undifferentiated GSCs using in vitro phage display technology. This GSCT peptide binds to isotypes of Nestin proteins specifically expressed in GSCs, enabling it to target Nestin-positive cells in human glioblastoma tissues. In human glioblastoma tissue specimens, the fluorescence-conjugated GSCT peptide could visualize putative GSC populations, showing its possible use as a diagnostic agent. GSCT peptide is also internalized into undifferentiated GSCs specifically in vitro, and moreover, intravenously injected GSCT peptide effectively penetrated into tissues, specifically accumulated in gliomas that arise from subcutaneous and orthotopic implantation, and predominantly targeted Nestin-positive cells in these tumors. Thus, our GSCT peptide may be useful for the development of more promising therapeutic and diagnostic modalities that target GSCs in brain tumors.

Time-resolved energy transduction in a quantum capacitor.

The capability to deposit charge and energy quantum-by-quantum into a specific atomic site could lead to many previously unidentified applications. Here we report on the quantum capacitor formed by a strongly localized field possessing such capability. We investigated the charging dynamics of such a capacitor by using the unique scanning tunneling microscopy that combines nanosecond temporal and subangstrom spatial resolutions, and by using Si(001) as the electrode as well as the detector for excitations produced by the charging transitions. We show that sudden switching of a localized field induces a transiently empty quantum dot at the surface and that the dot acts as a tunable excitation source with subangstrom site selectivity. The timescale in the deexcitation of the dot suggests the formation of long-lived, excited states. Our study illustrates that a quantum capacitor has serious implications not only for the bottom-up nanotechnology but also for future switching devices.

Detecting vegetation cover change on the summit of Cadillac Mountain using multi-temporal remote sensing datasets: 1979, 2001, and 2007.

This study examines the efficacy of management strategies implemented in 2000 to reduce visitor-induced vegetation impact and enhance vegetation recovery at the summit loop trail on Cadillac Mountain at Acadia National Park, Maine. Using single-spectral high-resolution remote sensing datasets captured in 1979, 2001, and 2007, pre-classification change detection analysis techniques were applied to measure fractional vegetation cover changes between the time periods. This popular sub-alpine summit with low-lying vegetation and attractive granite outcroppings experiences dispersed visitor use away from the designated trail, so three pre-defined spatial scales (small, 0-30 m; medium, 0-60 m; and large, 0-90 m) were examined in the vicinity of the summit loop trail with visitor use (experimental site) and a site chosen nearby in a relatively pristine undisturbed area (control site) with similar spatial scales. Results reveal significant changes in terms of rates of vegetation impact between 1979 and 2001 extending out to 90 m from the summit loop trail with no management at the site. No significant differences were detected among three spatial zones (inner, 0-30 m; middle, 30-60 m; and outer, 60-90 m) at the experimental site, but all were significantly higher rates of impact compared to similar spatial scales at the control site (all p < 0.001). In contrast, significant changes in rates of recovery between 2001 and 2007 were observed in the medium and large spatial scales at the experimental site under management as compared to the control site (all p < 0.05). Also during this later period a higher rate of recovery was observed in the outer zone as compared to the inner zone at the experimental site (p < 0.05). The overall study results suggest a trend in the desired direction for the site and visitor management strategies designed to reduce vegetation impact and enhance vegetation recovery at the summit loop trail of Cadillac Mountain since 2000. However, the vegetation recovery has been rather minimal and did not reach the level of cover observed during the 1979 time period. In addition, the advantages and some limitations of using remote sensing technologies are discussed in detecting vegetation change in this setting and potential application to other recreation settings.

Artificial neural network models for prediction of intestinal permeability of oligopeptides.

BACKGROUND: Oral delivery is a highly desirable property for candidate drugs under development. Computational modeling could provide a quick and inexpensive way to assess the intestinal permeability of a molecule. Although there have been several studies aimed at predicting the intestinal absorption of chemical compounds, there have been no attempts to predict intestinal permeability on the basis of peptide sequence information. To develop models for predicting the intestinal permeability of peptides, we adopted an artificial neural network as a machine-learning algorithm. The positive control data consisted of intestinal barrier-permeable peptides obtained by the peroral phage display technique, and the negative control data were prepared from random sequences. RESULTS: The capacity of our models to make appropriate predictions was validated by statistical indicators including sensitivity, specificity, enrichment curve, and the area under the receiver operating characteristic (ROC) curve (the ROC score). The training and test set statistics indicated that our models were of strikingly good quality and could discriminate between permeable and random sequences with a high level of confidence. CONCLUSION: We developed artificial neural network models to predict the intestinal permeabilities of oligopeptides on the basis of peptide sequence information. Both binary and VHSE (principal components score Vectors of Hydrophobic, Steric and Electronic properties) descriptors produced statistically significant training models; the models with simple neural network architectures showed slightly greater predictive power than those with complex ones. We anticipate that our models will be applicable to the selection of intestinal barrier-permeable peptides for generating peptide drugs or peptidomimetics.

Cycloaddition reaction of 1,3-butadiene with a symmetric Si adatom pair on the Si(111)7x7 surface.

We first found experimentally a cycloaddition reaction of a molecule on a symmetry Si pair, 1,3-butadiene on the Si adatom pair of Si(111)7x7, while up to now only asymmetric Si pairs were reported to be involved in cycloaddition reactions on Si surfaces. As the symmetry of a Si pair is expected to influence significantly a cycloaddition product and a reaction pathway, the [4+2]-like cycloaddition product of 1,3-butadiene on the Si adatom pair is suggested to form through a concerted reaction pathway in comparison to a stepwise reaction pathway, which is favorable in the formation of the [4+2]-like cycloaddition product on the asymmetric Si pair (the Si adatom-restatom pair).