Graphene-graphene oxide floating gate transistor memory

A novel transparent, flexible, graphene channel floating-gate transistor memory (FGTM) device is fabricated using a graphene oxide (GO) charge trapping layer on a plastic substrate. The GO layer, which bears ammonium groups (NH3+), is prepared at the interface between the crosslinked PVP (cPVP) tunneling dielectric and the Al2 O3 blocking dielectric layers. Important design rules are proposed for a high-performance graphene memory device: (i) precise doping of the graphene channel, and (ii) chemical functionalization of the GO charge trapping layer. How to control memory characteristics by graphene doping is systematically explained, and the optimal conditions for the best performance of the memory devices are found. Note that precise control over the doping of the graphene channel maximizes the conductance difference at a zero gate voltage, which reduces the device power consumption. The proposed optimization via graphene doping can be applied to any graphene channel transistor-type memory device. Additionally, the positively charged GO (GO-NH3+) interacts electrostatically with hydroxyl groups of both UV-treated Al2 O3 and PVP layers, which enhances the interfacial adhesion, and thus the mechanical stability of the device during bending. The resulting graphene-graphene oxide FGTMs exhibit excellent memory characteristics, including a large memory window (11.7 V), fast switching speed (1 μs), cyclic endurance (200 cycles), stable retention (10(5) s), and good mechanical stability (1000 cycles).

Chemical modification of graphene aerogels for electrochemical capacitor applications

The demand for graphene aerogel-based ECs with enhanced capacitance and mechanical properties has led to the development of diverse synthetic techniques.

A case of perforating dermatofibroma with floret-like giant cells

Dermatofibromas are slow-growing solitary nodules, composed mostly of a dermal proliferation of spindle cells and epithelioid cells. Some dermatofibromas present with multinucleated giant cells, such as Touton, foreign body, and osteoclast-like cells. We report a case of dermatofibroma containing both Touton giant cells and floret-type cells. A 12-year-old boy presented with a 6-mm, firm, nontender, dusky-red to greyish dermal nodule on his left popliteal fossa. As suggested clinically by the central opening, perforation of the epidermis with partial extrusion of the dermal components, including macrophages and vertically oriented collagen bundles, via transepidermal elimination, were detected. In the upper dermis, collagen trapping and mostly epithelioid cells with many giant cells were seen, while the lower part contained mainly spindle cells in a storiform pattern. Multinucleated giant cells scattered in the upper dermis were mainly floret-type multinucleated giant cells with star-shaped cytoplasmic projections, associated with some Touton giant cells. To our knowledge, this is the first report of a perforating dermatofibroma with floret-type multinucleated giant cells.

A magnetic particle time-of-flight (MagPTOF) diagnostic for measurements of shock- and compression-bang time at the NIF (invited)

A magnetic particle time-of-flight (MagPTOF) diagnostic has been designed to measure shock- and compression-bang time using D(3)He-fusion protons and DD-fusion neutrons, respectively, at the National Ignition Facility (NIF). This capability, in combination with shock-burn weighted areal density measurements, will significantly constrain the modeling of the implosion dynamics. This design is an upgrade to the existing particle time-of-flight (pTOF) diagnostic, which records bang times using DD or DT neutrons with an accuracy better than ±70 ps [H. G. Rinderknecht et al., Rev. Sci. Instrum. 83, 10D902 (2012)]. The inclusion of a deflecting magnet will increase D(3)He-proton signal-to-background by a factor of 1000, allowing for the first time simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions at the NIF.

Anomalous nanoinclusion effects of 2D MoS2 and WS2 nanosheets on the mechanical stiffness of polymer nanocomposites

Polymer inorganic nanosheet composites hold great promise in enhancing their physical and mechanical properties by increasing the interfacial area. Herein, we demonstrate the nanoinclusion effects of two-dimensional (2D) molybdenum disulfide (MoS2) and tungsten disulfide (WS2) nanosheets on the mechanical properties of the poly(vinyl alcohol) (PVA) polymer. At very small amounts of nanosheets (0.9 wt% for MoS2 and 2.0 wt% for WS2), nanocomposite films exhibit up to 65% improved mechanical properties than the neat PVA film because of strong non-covalent polymer-filler interactions by means of large contact area induced by the 2D geometry of nanosheets. As demonstrated by the decrease in the crystallinity of PVA and the increase in the glass transition temperature, 2D MoS2 is a more attractive filler than 2D WS2 in terms of reinforcing mechanical properties of PVA. These findings fit well with a modified Halpin-Tsai (H-T) model including a nanoscale interfacial layer that can support the observed reinforcements with extremely small 2D filler loadings. This study highlights the strong interplay between the polymer and inorganic nanosheets which plays an important role in greatly improving the mechanical stability of nanocomposites.

Magnetization amplified by structural disorder within nanometre-scale interface region

Direct magnetization measurements from narrow, complex-shaped antiphase boundaries (APBs; that is, planar defect produced in any ordered crystals) are vitally important for advances in materials science and engineering. However, in-depth examination of APBs has been hampered by the lack of experimental tools. Here, based on electron microscopy observations, we report the unusual relationship between APBs and ferromagnetic spin order in Fe₇₀Al₃₀. Thermally induced APBs show a finite width (2–3 nm), within which significant atomic disordering occurs. Electron holography studies revealed an unexpectedly large magnetic flux density at the APBs, amplified by approximately 60% (at 293 K) compared with the matrix value. At elevated temperatures, the specimens showed a peculiar spin texture wherein the ferromagnetic phase was confined within the APB region. These observations demonstrate ferromagnetism stabilized by structural disorder within APBs, which is in direct contrast to the traditional understanding. The results accordingly provide rich conceptual insights for engineering APB-induced phenomena.

Atomic disordering in antiphase boundary regions is believed to deteriorate ferromagnetic spin order in many alloys and compounds. Here, using electron microscopy, Murakami et al. report the unusual relationship between thermal antiphase boundaries and ferromagnetic spin order in Fe₇₀Al₃₀.

CO2-activated, hierarchical trimodal porous graphene frameworks for ultrahigh and ultrafast capacitive behavior

Herein, we demonstrate CO2-activated macroscopic graphene architectures with trimodal pore systems that consist of 3D inter-networked macroporosity arising from self-assembly, mesoporosity arising from the intervoids of nanosheets, and microporosity via CO2 activation. The existence of micropores residing in hierarchical structures of trimodal porous graphene frameworks (tGFs) contributes to greatly improve the surface area and pore volume, which are ∼3.8 times greater than typical values of existing 3D macroporous graphene monoliths. As confirmed by the specific capacity, the kinetic parameters, and the regeneration capability for chemical adsorption as well as the specific capacitance, the rate capability, and the cycle stability for electrochemical energy storage, the tGFs have an ideal texture for high performance capacitive materials. Furthermore, the tGFs obtain the structurally and energetically homogeneous surface active sites, which dominantly operate through the π-π interactions for adsorption. Consequently, the ultrahigh capacitance and ultrafast capacitive performance of the tGFs for both chemical and electrochemical adsorptions are attributed to hierarchical trimodal porosity and surface chemistry. These results offer a chemical approach combining self-assembly with conventional activation for the construction of 3D hierarchical structures with multimodal porosity.

Superior pseudocapacitive behavior of confined lignin nanocrystals for renewable energy-storage materials

Strong demand for high-performance energy-storage devices has currently motivated the development of emerging capacitive materials that can resolve their critical challenge (i.e., low energy density) and that are renewable and inexpensive energy-storage materials from both environmental and economic viewpoints. Herein, the pseudocapacitive behavior of lignin nanocrystals confined on reduced graphene oxides (RGOs) used for renewable energy-storage materials is demonstrated. The excellent capacitive characteristics of the renewable hybrid electrodes were achieved by synergizing the fast and reversible redox charge transfer of surface-confined quinone and the interplay with electron-conducting RGOs. Accordingly, pseudocapacitors with remarkable rate and cyclic performances (~96 % retention after 3000 cycles) showed a maximum capacitance of 432 F g(-1), which was close to the theoretical capacitance of 482 F g(-1) and sixfold higher than that of RGO (93 F g(-1)). The chemical strategy delineated herein paves the way to develop advanced renewable electrodes for energy-storage applications and understand the redox chemistry of electroactive biomaterials.

Association between BMP-2 and COL6A1 gene polymorphisms with susceptibility to ossification of the posterior longitudinal ligament of the cervical spine in Korean patients and family members

COL6A1 and BMP-2 genes have been implicated in ossification of the posterior longitudinal ligament (OPLL) susceptibility in Japanese and Chinese Han populations. However, no study has yet investigated the DNA of unaffected family members of patients with OPLL. This study investigated differences in genetic polymorphisms of BMP-2 and COL6A1 between Korean patients with OPLL and their family members (with and without OPLL). A total of 321 subjects (110 patients with OPLL and 211 family members) were enrolled in the study. Associations between two single nucleotide polymorphisms (SNPs) of the BMP-2 gene (Ser37Ala and Ser87Ser) and two SNPs of COL6A1 [promoter (-572) and intron 33 (+20)] with susceptibility to OPLL of the cervical spine were investigated between the two groups (OPLL+ and OPLL-). Of the 321 subjects, 162 had cervical OPLL (50.4%; 110 patients, 52 family members). There was a familial tendency of OPLL in 34 of the 110 families (30.9%). Allele and haplotype frequencies of the four SNPs in the BMP-2 and COL6A1 genes did not differ significantly between the OPLL+ and OPLL- groups, even when excluding participants over 50 years of age. This is the first report identifying SNPs of COL6A1 and BMP-2 in Korean patients and family members with OPLL. Although allele and haplotype frequencies were similar with those of a previous study in Japanese and Chinese patients, unaffected family members also showed similar rates of these SNPs in the present study. These results suggest that these SNPs may not directly influence the expression of OPLL.

PATHOME: an algorithm for accurately detecting differentially expressed subpathways

The translation of high-throughput gene expression data into biologically meaningful information remains a bottleneck. We developed a novel computational algorithm, PATHOME, for detecting differentially expressed biological pathways. This algorithm employs straightforward statistical tests to evaluate the significance of differential expression patterns along subpathways. Applying it to gene expression data sets of gastric cancer (GC), we compared its performance with those of other leading programs. Based on a literature-driven reference set, PATHOME showed greater consistency in identifying known cancer-related pathways. For the WNT pathway uniquely identified by PATHOME, we validated its involvement in gastric carcinogenesis through experimental perturbation of both cell lines and animal models. We identified HNF4α-WNT5A regulation in the cross-talk between the AMPK metabolic pathway and the WNT signaling pathway, and further identified WNT5A as a potential therapeutic target for GC. We have demonstrated PATHOME to be a powerful tool, with improved sensitivity for identifying disease-related dysregulated pathways.

Huge abdominal cyst occurred after kidney transplantation

This case demonstrates continuous ambulatory peritoneal dialysis-related endometrial tissue migration and occurrence of huge cystic endometriosis by the recovery of menstrual period after kidney transplantation.

Phase transition method to form Group 6A nanoparticles on carbonaceous templates

Considerable effort has been made to develop unique methods of preparing and characterizing nanoparticles and nanocomposites in order to exploit the true potential of nanotechnology. We used a facile, versatile phase-transition method for forming Group 6A nanoparticles on carbonaceous templates to produce homogeneous 5-10 nm diameter Group 6A nanoparticles on carbon nanotubes (CNTs) and reduced graphene oxide (RGO), to obtain nanocomposites. The method involved melting and recrystallizing mixtures of elemental sulfur and either CNTs or RGO on carbonaceous templates. The surface tension and hydrophilicity of the molten Group 6A species surfaces and the oxygen functional groups on the carbonaceous template surfaces were considered in depth to provide important guidelines for forming Group 6A nanoparticles on carbonaceous templates. The surface tension of the molten Group 6A species should be intrinsically low, leading to effective wetting on the carbonaceous template. In addition, the molten Group 6A species hydrophilic surfaces were essential for enabling hydrophilic-hydrophilic interaction for selective wetting at the oxygen functional groups on the carbonaceous template, leading to the heterogeneous nucleation of nanoparticles. Furthermore, the size and morphology (isolated vs layer-like) of the Group 6A nanoparticles were tuned by adjusting the oxidation state of the carbonaceous template. We investigated the potential application of the nanocomposites prepared using this method to cathode materials in lithium-sulfur secondary batteries.

Relation between sleep duration, overweight, and metabolic syndrome in Korean adolescents

BACKGROUND AND AIMS

The increasing prevalence of obesity has been paralleled by a trend of reduced sleep duration. Sleep is considered a modulator of neuroendocrine function. The aim of this study was to determine the relation between sleep duration, overweight, and metabolic syndrome in Korean adolescents.

METHODS AND RESULTS

This study was based on data from the Korean National Health and Nutrition Examination Survey (KNHANES) IV. Data from 1187 adolescents aged 12-18 years were included in the analysis. Subjects were classified according to self-reported sleep duration: ≤ 5 h, 6-7 h, 8-9 h, and ≥ 10 h. We analysed the association between sleep duration, overweight, and metabolic syndrome after adjustment for potential confounding variables. Body mass index (BMI), waist circumference (WC), and diastolic blood pressure (DBP) were higher in subjects who slept ≤ 5 h, and triglyceride level was higher in subjects who slept ≥ 10 h. According to logistic regression analysis, subjects who slept ≤ 5 h had a higher risk of overweight (odds ratio (OR) 2.04, 95% confidence interval (CI) 1.17-3.57) and elevated blood pressure (BP) (OR 2.11, 95% CI 1.22-3.65). We did not find any association between sleep duration and metabolic syndrome. Subjects who slept ≥ 10 h had a higher risk of hypertriglyceridemia (OR 2.17, 95% CI 1.14-4.13).

CONCLUSION

Short sleep duration was associated with overweight in adolescents. Although there was no association between sleep duration and metabolic syndrome, short sleep duration was associated with elevated BP and long sleep duration was associated with hypertriglyceridemia.

Multiwalled carbon nanotubes coated with a thin carbon layer for use as composite electrodes in supercapacitors

A sucrose-derived thin carbon layer (CS) is coated onto the surface of multiwalled carbon nanotubes (MWCNTs). The resulting composite electrode (CSN) has a larger capacitance than that of the MWCNTs and the CS.

Surface functional groups of carbon nanotubes to manipulate capacitive behaviors

The covalent functionalization of carbon nanotubes (CNTs) is a basic but important chemistry that can modify their physicochemical properties, resolve their poor dispersion capability, and improve their capacitance to enable their use as high-energy supercapacitors. However, the relationship between functional groups on the CNT surface and their capacitive characteristics has not yet been explored. Here, we demonstrate the influence of carboxylic, sulfonic, and amine groups tethered to CNTs (Cf-CNTs, Sf-CNTs, and Nf-CNTs, respectively) on capacitor performance in an organic electrolyte. The Cf-CNTs show the highest specific capacitance of 129.4 F g(-1), four-fold greater than 31.2 F g(-1) of pristine CNTs, but they reveal the lowest rate capability of 57%. In contrast, the Sf- and Nf-CNTs exhibit specific capacitances of 70.9 F g(-1) and 83.6 F g(-1), two-fold greater than that of pristine CNTs, along with a good rate capability greater than 80%. Despite their pseudocapacitive nature, all functionalized CNTs show a cyclic stability of more than 80% after 500 cycles due to the electrochemical stability of the functional groups. As demonstrated by spectroscopic analysis, the supercapacitive behaviors of the functionalized CNTs originate from specific interactions between functional groups and lithium ions and the alteration of the electronic structure arising from covalent functionalization.

Gender and age differences in the impact of overweight on obesity-related quality of life among Korean adults

SUMMARY

OBJECTIVE

To investigate gender and age difference in impact of overweight on health-related quality of life (HRQOL) among Korean adults.

METHODS

Cross-sectional obesity-related quality of life (QOL) scores were measured by a Korean obesity-related QOL scale (KOQOL) from 448 Korean adults aged 20-80 years. A body mass index (BMI) was categorized with normal-weight as BMI < 23 kg/m(2), overweight as BMI ≥ 23 kg/m(2) based on the alternative cutoff points for Asians. Each gender was respectively stratified by median age, 45 years for men and 50 years for women, to examine the obesity-related QOL by age groups.

RESULTS

Women had a poorer obesity-related QOL compared to men (p < 0.001). In the younger age group, overweight women had a poorer obesity-related QOL compared with normal-weight women (p < 0.001), however normal-weight and overweight men showed no difference in obesity-related QOL. In the older age group, overweight men showed better QOL on the domains of work-related and psychosocial health than those for normal-weight men, but overweight women still suffered from work-related and routine life QOL.

CONCLUSIONS

This study showed the impact of overweight on obesity-related QOL was different for gender and age group. We should consider the results to manage weight in overweight persons.

Abstract P1-08-35: Androgen receptor expression and changes in serum dehydroepiandrosterone sulfate levels in locally advanced breast cancer patients who received neoadjuvant chemotherapy

Purpose: The associations between androgen receptor (AR) expression, serum dehydroepiandrosterone-sulfate (DHEA-S) level and response to neoadjuvant chemotherapy (NCT) were investigated in locally advanced breast cancer patients who received NCT.

Methods: Between May 2008 and April 2013, a total of 346 patients underwent NCT mainly based on anthracycline with or without taxane regimens. Biomarkers including AR were immunohistochemically determined using biopsy specimens before NCT and tumors with ≥ 1% nuclear staining were considered positive for AR. Changes in serum DHEA-S levels before and after NCT were examined by chemiluminescent immunoassay (Access DHEA-S, Beckman Coulter, Inc., Brea, CA) in 205 (59.2%) patients. Pathologic complete response (pCR) was defined as the absence of residual invasive carcinomas in the surgical specimens of breast and lymph nodes. Breast cancer subtypes were categorized by immunohistochemistry of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67.

Results: Mean age at diagnosis was 49.7 years (range, 26–76). Clinical tumor size was ≥ 2cm in 243 (70.2%) patients and 318 (91.9%) showed node-positive disease at initial presentation. AR-positive tumor was determined in 195 (56.4%) patients and 95 (27.5%) achieved pCR after NCT. AR-negative tumors were significantly associated with grade III, ER-negative, PR-negative, HER2-negative, high Ki-67 index, and triple-negative subtype tumors. By univariate logistic regression analysis, AR-negative tumor showed significantly higher odds ratio of 1.650 (95% CI, 1.026–2.654; p-value, 0.039) for achievement of pCR. Nevertheless, not AR status but breast cancer subtype, longer duration of NCT and use of targeted agents remained to be significant for pCR by multivariate model. In the analysis of subgroup by breast cancer subtypes, AR-negative tumor was associated with pCR in 75 patients with the low proliferative luminal A subtype, while AR-positive tumor achieved higher pCR in 59 patients with the HER2-positive luminal B subtype. In 205 patients available for serum DHEA-S levels, there was no difference in DHEA-S between pCR and non-pCR groups, although a trend of decrease in DHEA-S after NCT was noted among postmenopausal AR-positive or luminal A subtype women who achieved pCR.

Conclusions: AR expression might predict pCR in locally advanced breast cancer patients who undergo NCT, but this implication could be different according to breast cancer subtypes. Clinical significance of changes in serum DHEA-S levels during NCT remains to be elucidated.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-08-35.

Structure and dynamics of colliding plasma jets

Monoenergetic-proton radiographs of laser-generated, high-Mach-number plasma jets colliding at various angles shed light on the structures and dynamics of these collisions. The observations compare favorably with results from 2D hydrodynamic simulations of multistream plasma jets, and also with results from an analytic treatment of electron flow and magnetic field advection. In collisions of two noncollinear jets, the observed flow structure is similar to the analytic model's prediction of a characteristic feature with a narrow structure pointing in one direction and a much thicker one pointing in the opposite direction. Spontaneous magnetic fields, largely azimuthal around the colliding jets and generated by the well-known ∇T(e)×∇n(e) Biermann battery effect near the periphery of the laser spots, are demonstrated to be "frozen in" the plasma (due to high magnetic Reynolds number Re(M)∼5×10(4)) and advected along the jet streamlines of the electron flow. These studies provide novel insight into the interactions and dynamics of colliding plasma jets.

Phylogenetic relationships of chrysanthemums in Korea based on novel SSR markers

Chrysanthemums are well known for their esthetic and medicinal values. Characterization of chrysanthemums is vital for their conservation and management as well as for understanding their genetic relationships. We found 12 simple sequence repeat markers (SSRs) of 100 designed primers to be polymorphic. These novel SSR markers were used to evaluate 95 accessions of chrysanthemums (3 indigenous and 92 cultivated accessions). Two hundred alleles were identified, with an average of 16.7 alleles per locus. KNUCRY-77 gave the highest polymorphic information content value (0.879), while KNUCRY-10 gave the lowest (0.218). Similar patterns of grouping were observed with a distance-based dendrogram developed using PowerMarker and model-based clustering with Structure. Three clusters with some admixtures were identified by model-based clustering. These newly developed SSR markers will be useful for further studies of chrysanthemums, such as taxonomy and marker-assisted selection breeding.