High-pressure hydrogen storage in zeolite-templated carbon (ZTC) was investigated at room temperature (30 °C). Several types of ZTCs with different surface areas and a nitrogen-doped ZTC were prepared. Their hydrogen storage performance at room temperature was examined and the results were compared with those of commercial activated carbons. At pressures below 10 MPa, the hydrogen uptake capacity was simply proportional to specific surface areas of the carbons, and both ZTCs and activated carbon showed almost the same heat of adsorption (6∼8 kJ mol−1). On the other hand, at pressures above 10 MPa, uniform micropores with a diameter of 1.2 nm in ZTCs played a more important role in capacity increase than the specific surface area. As a result, the ZTC with the largest surface area (3370 m2 g−1) exhibited hydrogen uptake as high as 2.2 wt % at 34 MPa. This value is much larger than that of the activated carbon, and such a difference in the capacity between ZTC and activated carbon cannot be explained by the difference in specific surface area alone. Moreover, by loading only a small amount of Pt nanoparticles (ca. 0.2 wt %) onto ZTC, hydrogen uptake capacity was increased from 0.87 to 0.95 wt % at 10 MPa. The increase of hydrogen uptake capacity by Pt loading can be ascribed to hydrogen spillover through the supported Pt nanoparticles to the carbon surface.
An oxidation-resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge-like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single-layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m 2 g −1 ). Moreover, the graphene-based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a suffi cient capacitance (125 F g −1 ), wide potential window (4 V), and good rate capability as an electrode material for electric double-layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg −1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge-like elastic property enables an advanced force-induced adsorption control.
BACKGROUND Intestinal and diffuse gastric carcinomas differ in morphology and growth behavior. Differentiated type gastric carcinoma (DGC), which corresponds roughly with the intestinal type of Lauren, can demonstrate phenotypic properties associated with mucin expression and brush border. However, their clinical significance is controversial. A classification based on mucin phenotype and brush border was performed to determine the clinicopathologic diversity of DGCs in their early stage. METHODS A total of 120 specimens from 116 DGC patients with definite submucosal invasion were evaluated both macroscopically and histologically. All sections were examined immunohistochemically with human gastric mucin, Muc‐2, and CD10 and with mucin histochemically with paradoxical concanavalin A staining and high iron Diamine‐Alcian Blue. They were classified into gastric type (G‐type), intestinal type (I‐type), mixed gastric and intestinal type (M‐type), or null type (N‐type) phenotypes. The immunoreactivity of E‐cadherin and β‐catenin also was investigated to determine the correlation between mucin phenotype and clinicopathologic factors. RESULTS The G‐type phenotype was found to be in contrast to I‐type: G‐type was an independent factor associated with lymph node metastasis. Significant correlations were observed between the G‐type phenotype and the complex type carcinoma found that was histologically: lymphatic invasion, lymph node metastasis, and the abnormal expression of E‐cadherin. A significant difference in the proportion of mucin phenotypes between papillary type and tubular type carcinoma was observed. G‐type was found to be the predominant phenotype in papillary carcinoma in contrast to tubular carcinoma. CONCLUSIONS The G‐type mucin phenotype and papillary adenocarcinoma should be distinguished from other types of DGCs because of their increased malignant potential in the incipient phase of invasion and metastasis. The significance of G‐type and papillary adenocarcinoma should be reflected in the treatment of patients with early stage DGCs, including endoscopic mucosal resection. Cancer 2000;89:724–32. © 2000 American Cancer Society.
Nano-confined spaces in nanoporous materials enable anomalous physicochemical phenomena. While most nanoporous materials including metal-organic frameworks are mechanically hard, graphene-based nanoporous materials possess significant elasticity and behave as nanosponges that enable the force-driven liquid–gas phase transition of guest molecules. In this work, we demonstrate force-driven liquid–gas phase transition mediated by nanosponges, which may be suitable in high-efficiency heat management. Compression and free-expansion of the nanosponge afford cooling upon evaporation and heating upon condensation, respectively, which are opposite to the force-driven solid–solid phase transition in shape-memory metals. The present mechanism can be applied to green refrigerants such as H 2 O and alcohols, and the available latent heat is at least as high as 192 kJ kg −1 . Cooling systems using such nanosponges can potentially achieve high coefficients of performance by decreasing the Young’s modulus of the nanosponge.
SummaryParkinson disease (PD) is a progressive neurological disease caused by selective degeneration of dopaminergic (DA) neurons in the substantia nigra. Although most cases of PD are sporadic cases, familial PD provides a versatile research model for basic mechanistic insights into the pathogenesis of PD. In this study, we generated DA neurons from PARK2 patient-specific, isogenic PARK2 null and PARK6 patient-specific induced pluripotent stem cells and found that these neurons exhibited more apoptosis and greater susceptibility to rotenone-induced mitochondrial stress. From phenotypic screening with an FDA-approved drug library, one voltage-gated calcium channel antagonist, benidipine, was found to suppress rotenone-induced apoptosis. Furthermore, we demonstrated the dysregulation of calcium homeostasis and increased susceptibility to rotenone-induced stress in PD, which is prevented by T-type calcium channel knockdown or antagonists. These findings suggest that calcium homeostasis in DA neurons might be a useful target for developing new drugs for PD patients.
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