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Background: IgE bound on the surface of mast cells contributes to the pathogenesis of chronic spontaneous urticaria (CSU). Atopy is a predisposing factor for CSU, where omalizumab is a widely used monoclonal antibody to control urticaria symptoms via capturing serum free IgE. However, the role of serum free IgE is not clarified in CSU. The present study evaluated the clinical relevance of serum free IgE in patients with CSU. Methods: Eighty-eight patients with CSU and 76 healthy controls (HCs) were enrolled in this study. Serum total and Dermatophagoides pteronyssinus (Der p)-specific IgE levels were measured by ImmunoCAPs. The serum free IgE levels were measured by ELISA using a novel IgETRAP, and their associations with clinical parameters, including urticaria activity score (UAS), were evaluated. Changes in serum free and total IgE levels after omalizumab treatment were observed in 23 CSU patients in comparison between responders (≥50% reduction in UAS) and non-responders (

Elevated expression of human enhancer filamentation 1 (HEF1; also known as NEDD9 or Cas-L) is an essential stimulus for the metastatic process of various solid tumors. This process requires HEF1 localization to focal adhesions (FAs). Although the association of HEF1 with FAs is considered to play a role in cancer cell migration, the mechanism targeting HEF1 to FAs remains unclear. Moreover, up-regulation of Polo-like kinase 1 (Plk1) positively correlates with human cancer metastasis, yet how Plk1 deregulation promotes metastasis remains elusive. Here, we report that casein kinase 1δ (CK1δ) phosphorylates HEF1 at Ser-780 and Thr-804 and that these phosphorylation events promote a physical interaction between Plk1 and HEF1. We found that this interaction is critical for HEF1 translocation to FAs and for inducing migration of HeLa cells. Plk1-docking phosphoepitopes were mapped/confirmed in HEF1 by various methods, including X-ray crystallography, and mutated for functional analysis in HeLa cells. In summary, our results reveal the role of a phosphorylation-dependent HEF1–Plk1 complex in HEF1 translocation to FAs to induce cell migration. Our findings provide critical mechanistic insights into the HEF1–Plk1 complex–dependent localization of HEF1 to FAs underlying the metastatic process and may therefore contribute to the development of new cancer therapies.

Two angucyclines, pseudonocardones D (1) and E (2), were isolated from Streptomyces sp. KCB15JA151. The planar structure was elucidated by comprehensive spectroscopic analysis. The absolute configuration of the sugar unit was determined based on the basis of coupling constants, ROESY, chemical derivatization and HPLC analysis. The biological activities of compounds 1 and 2 were examined by performing a computational target prediction, which led to tests of the antiestrogenic activity. The result suggested that compound 1 might be an ERα antagonist.

Background It has been known that a high serum total immunoglobulin E (IgE) level is a predisposing factor of allergic asthma; however, there are considerable limitations to apply it in clinical practice. Objective To determine the clinical significance of the serum-free IgE level in patients with adult asthma. Methods We measured free IgE levels using our homemade enzyme-linked immunosorbent assay by applying a novel IgE TRAP protein (GI innovation, Seoul, Republic of Korea) in sera of adults with asthma (n = 116) compared with healthy controls (n = 32); enzyme-linked immunosorbent assay inhibition test was performed to validate its binding specificity. Associations between asthma-related clinical and laboratory parameters were analyzed. The diagnostic value and cutoff point for detecting atopy and type 2 asthma were determined using receiver operating characteristic curve analysis. Results The serum-free IgE levels were significantly higher in adults with asthma than in healthy controls and were significantly associated with atopic status and type 2 asthma (all P Conclusion It is suggested that a higher serum-free IgE level may be a useful biomarker of atopy and type 2 asthma in adults with asthma.

In the course of searching for anti-neuroinflammatory metabolites from marine fungi, citreohybridonol was isolated from marine-derived fungal strain Toxicocladosporium sp. SF-5699. Citreohybridonol inhibited production of nitric oxide (NO) and prostaglandin E2 (PGE2) in BV2 cells stimulated by lipopolysaccharide (LPS). Citreohybridonol also suppressed the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and other pro-inflammatory cytokines including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the LPS-stimulated cells. In the further study, citreohybridonol disturbed nuclear translocation of nuclear factor-kappa B (NF-κB) in LPS-stimulated BV2 cells by inhibiting the phosphorylation of the inhibitor kappa B-α (IκB-α). Citreohybridonol also had inhibitory effect on the LPS-stimulated phosphorylation of p38 mitogen-activated protein kinase (MAPK). Finally, citreohybridonol suppressed the protein expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) in LPS-induced BV2 cells. These results suggest that citreohybridonol has anti-neuroinflammatory effect in LPS-stimulated BV2 cells by modulating TLR4-mediated several inflammatory pathways such as NF-κB and p38 MAPK pathways.

Twelve metabolites, including five highly oxygenated azaphilones, geumsanols A-E, along with seven known analogues were isolated from Penicillium sp. KCB11A109, a fungus derived from a ginseng field. Their structures were assigned by spectroscopic means (NMR and MS), and stereochemistries were determined by extensive spectroscopic analyses ((1)H-(1)H coupling constants, NOESY, and HETLOC) and chemical derivatizations (modified Mosher's method and acetonide formation). The isolates were evaluated for their anticancer, antimicrobial, antimalarial activities, and phenotypic effects in zebrafish development. Of these compounds possessing no pyranoquinone core, only geumsanol E exhibited cytotoxic activities and toxic effects on zebrafish embryos, suggesting that a double bond at C-11 and C-12 is important for biological activity.

This study was conducted to isolate and identify an active compound possessing anti-allergic property from the Jeju Island inhabiting Sargassum horneri (S. horneri). The ethanol extract of S. horneri (SHE) exhibited an anti-allergic effect via the reduction of β-hexosaminidase release in immunoglobulin E (IgE)/bovine serum albumin (BSA)-stimulated bone marrow-derived cultured mast cells (BMCMCs). SHE was subjected to liquid phase fractionation obtaining the hexane fraction, and this was further purified via ODS column chromatography and prep-C18 HPLC. The isolated compound was identified as mojabanchromanol (MC) by 1H, 13C NMR, and LCMS analysis. Isolated MC showed a higher inhibitory effect on the β-hexosaminidase release than those of SHE without cytotoxicity. Moreover, MC inhibited the mRNA expression levels of allergic cytokines in BMCMCs. This is the first report to inform on the anti-allergic property of MC isolated from S. horneri. In conclusion, SHE, as well as MC, is applicable in the development of functional health food, cosmetics, and pharmaceutical products exhibiting anti-allergic effects.

Autophagy plays a major role in cell survival and has therefore been exploited as an important strategy in cancer therapy. In this study, we evaluated the autophagy-regulatory effects of kushenol E (KE), a bi-prenylated flavonoid isolated from Sophora flavescens and found that KE increased LC3B-II levels while inducing the formation of autophagic vacuoles and immature autophagosomes in HeLa and HCT116 cells. Transmission electron microscopy images revealed that KE treatment generates immature autophagosomes. Furthermore, KE inhibited autophagosome maturation as demonstrated by blocking the degradation of EGFP puncta in HeLa cells stably expressing EGFP-mRFP-LC3B. It also reduced lysosomal activity and cathepsin maturation by disrupting lysosomal positioning, subsequently inducing apoptosis. Further, a combinatorial approach employing cellular thermal shift assays, revealed valosin-containing protein (VCP)/p97 as a potential target protein of KE; the knockdown and overexpression of VCP/p97 confirmed its involvement in regulating lysosomal positioning for autophagy maturation via direct interactions with KE. Thus, KE may possess autophagy-regulating properties mediated by binding to VCP/p97.

Two new macrolide metabolites of the hygrolidin family, catenulisporidins A and B (1 and 2), together with a known compound hygrolidin (3), were isolated from the culture broth of the rare actinobacterium Catenulispora sp. KCB13F192. Their structures were elucidated on the basis of HRESIMS spectrometric and NMR spectroscopic analyses. Catenulisporidins A and B are the first example of natural hygrolidin and bafilomycin derivatives featuring a modified macrolide ring, and catenulisporidin A possesses a tetrahydrofuran ring through an ether linkage between C-7 and C-10. In cell-based fluorescent imaging and immunoblot assays, the three compounds were shown to inhibit autophagic flux in HeLa cells.

Cellulose nanocrystals (CNCs), a biomaterial with high added value, were obtained from pure cellulose, Eucalyptus holocellulose, unbleached Kraft pulp, and sugarcane bagasse, by fibrillating these biomass substrates using wet disk milling (WDM) followed by enzymatic hydrolysis using endoglucanase/β-glucosidase. The hydrolysis experiments were conducted using the commercial enzyme OptimashBG or a blend of Pyrococcus horikoshii endoglucanase and Pyrococcus furiosus β-glucosidase. The fibrillated materials and CNCs were analyzed by X-ray diffraction, atomic force microscopy, scanning electron microscopy, and the specific surface area (SSA) was measured. WDM resulted in the formation of long and twisted microfibers of 1000-5000 nm in length and 4-35 nm in diameter, which were hydrolyzed into shorter and straighter CNCs of 500-1500 nm in length and 4-12 nm in diameter, with high cellulose crystallinity. Therefore, the CNC's aspect ratio was successfully adjusted by endoglucanases under mild reaction conditions, relative to the reported acidic hydrolysis method.

Tetramic acid containing a decalin ring such as equisetin and phomasetin is one of the characteristic scaffolds found in fungal bioactive secondary metabolites. Polyketide (PKS)-nonribosomal peptide synthetase (NRPS) hybrid enzyme is responsible for the synthesis of the polyketide scaffold conjugated with an amino acid. PKS-NRPS hybrid complex programs to create structural diversity in the polyketide backbone have begun to be investigated, yet mechanism of control of the stereochemistry in a decalin formation via a Diels-Alder cycloaddition remains uncertain. Here, we demonstrate that fsa2, which showed no homology to genes encoding proteins of known function, in the fsa cluster responsible for equisetin and fusarisetin A biosynthesis in Fusarium sp. FN080326, is involved in the control of stereochemistry in decalin formation via a Diels-Alder reaction in the equisetin biosynthetic pathway.

The small fuel cell is being researched as an alternative power source to the Li-ion battery in mobile phone. In this paper, a direct hydrogen fuel cell system which powers a mobile phone without a supplementary battery is compactly integrated below 25 ml volume at the backside of the phone. The system consists of a small (8 ml) metal hydride hydrogen storage tank with 4 L hydrogen storage or an energy density of ∼640 W h/L, a thin air-breathing planar polymer electrolyte membrane fuel cell (PEMFC) stack (13.44 cm 2 × 3 mm for a volumetric power density of 335 W/L), miniature pressure regulator, and a high efficiency DC–DC voltage converting circuitry. The hydrogen storage tank is packed with the AB 5 type metal hydride alloy. The eight-cell air-breathing planar stack (8 ml) is very thin (3 mm) due to a thin flexible printed circuit board current collectors as well as a unique riveting assembly and is capable of a robust performance of 2.68 W (200 mW/cm 2 ). A miniature pressure regulator is compact with fluidic and electrical connections within 4 ml. A miniature DC–DC voltage converter operates at an overall efficiency of 90%. Consequently, the estimated energy density of a fully integrated fuel cell system is 205 W h/L (70.5 W h/kg).

1. Subject and sourceThe Rhododendron genus containing over 850 species is one of the largest genera in the family Ericaceae. The genus ismostly distributed in Asia and sparsely populated in North America and Europe (Popescu and Kopp, 2013). Rhododendronbrachycarpum G. Don is an evergreen indeciduous broad-leaved shrub and utilized for alleviation of diabetes, hypertensionand rheumatoid arthritis (Jang et al., 2005). Radical climate changes have played a central role in reducing the population,leading its designation as an endangered and rare species (Lee et al., 2002; Lee and Shim, 2011). In our continuing efforts todiscoverpotentialvalue of theKoreanendangeredspecies, weherein describe theisolation and structuralcharacterization ofa new kaurane-type diterpenoid glycoside

LC/MS-based chemical screening of fungal extract fraction library led to identification of three 2,3-aryl substituted furanone metabolites (1–3), including one known butenolide glycoside (1) whose stereochemistry remained unsolved and two new compounds gotjawaside and gotjawalide (2 and 3), from Auxarthron sp. KCB15F070, a fungus isolated from a soil sample of the volcanic island Jeju, Korea. Their planar structures were elucidated by 1D- and 2D-NMR spectroscopic and HRESIMS spectrometric techniques, and the absolute configurations of three compounds were solved using a combination of chemical derivatizations and computational analysis of vibrational circular dichroism (VCD) spectra.

Chrysin (5,7-dihydroxyflavone), a natural flavonoid widely distributed in plants, reportedly has chemopreventive properties against various cancers. However, the anticancer activity of chrysin observed in in vivo studies has been disappointing. Here, we report that a chrysin derivative, referred to as compound 69407, more strongly inhibited EGF-induced neoplastic transformation of JB6 P+ cells compared with chrysin. It attenuated cell cycle progression of EGF-stimulated cells at the G1 phase and inhibited the G1/S transition. It caused loss of retinoblastoma phosphorylation at both Ser-795 and Ser-807/811, the preferred sites phosphorylated by Cdk4/6 and Cdk2, respectively. It also suppressed anchorage-dependent and -independent growth of A431 human epidermoid carcinoma cells. Compound 69407 reduced tumor growth in the A431 mouse xenograft model and retinoblastoma phosphorylation at Ser-795 and Ser-807/811. Immunoprecipitation kinase assay results showed that compound 69407 attenuated endogenous Cdk4 and Cdk2 kinase activities in EGF-stimulated JB6 P+ cells. Pulldown and in vitro kinase assay results indicated that compound 69407 directly binds with Cdk2 and Cdk4 in an ATP-independent manner and inhibited their kinase activities. A binding model between compound 69407 and a crystal structure of Cdk2 predicted that compound 69407 was located inside the Cdk2 allosteric binding site. The binding was further verified by a point mutation binding assay. Overall results indicated that compound 69407 is an ATP-noncompetitive cyclin-dependent kinase inhibitor with anti-tumor effects, which acts by binding inside the Cdk2 allosteric pocket. This study provides new insights for creating a general pharmacophore model to design and develop novel ATP-noncompetitive agents with chemopreventive or chemotherapeutic potency. Background: Binding to the ATP site results in poor selectivity; therefore, development of ATP-noncompetitive inhibitors is needed. Results: A modified chrysin with anticancer activity targets Cdks and binds to a Cdk2 allosteric site, not the ATP pocket. Conclusion: Modified chrysin is a novel ATP-noncompetitive inhibitor. Significance: This pharmacophore model might provide insights for the development of new ATP-noncompetitive agents.

The anti-apoptotic oncogene K-RAS is hypothesized to increase the antioxidant status of cells, thereby protecting them from generation of reactive oxygen species (ROS). Therefore, we examined whether K-RAS overcomes hydrogen peroxide (H2O2)-mediated apoptosis in the human fetal prostate epithelial cell 267B1. In this study, we found that treatment of 267B1 cells with H2O2 resulted in significant reduction of cell growth, which was associated with cytochrome-c release and caspase-3 activation. However, mutated K-RAS transformation (268B1/K-RAS) rendered 267B1 cells reduction of the resistance to H2O2-induced apoptosis through suppression of ROS generation. In addition, we analyzed profiling of gene expression in K-RAS transformation and found that gamma-glutamyltransferase 2 (GGT2) most highly expressed. Transient knockdown of K-RAS resulted in a significant downregulation of GGT gene expression. We also revealed that expression of GGT2 gene is closely regulated by the ERK signal pathway in 267B1/K-RAS cells. In addition, the anti-apoptotic effect of mutated K-RAS was attenuated by treatment with GGT2 RNA interference through inhibition of ROS generation, suggesting that mutated K-RAS mediates resistance to H2O2-induced apoptosis through GGT2 activation. These results importantly provide mechanistic insights on the anti-apoptotic activity of mutated K-RAS.

Patulin is a fungal mycotoxin of Aspergilus and Penicillium that is commonly found in rotting fruits and exerts its potential toxic effect mainly by reactive oxygen species (ROS) generation. However, the effect of patulin on cancer cells as well as its intracellular mechanism has been controversial and not clearly defined yet. In this study, patulin was found to induce G1/S accumulation and cell growth arrest accompanied by caspase-3 activation, PARP cleavage and ATF3 expression in human colon cancer cell line HCT116. Ser/Thr phosphorylation of a transcription factor, EGR-1, was increased while its expression did not change upon patulin treatment to the cells. Knockdown of ATF3 and EGR-1 using their respective siRNAs showed EGR-1 dependent ATF3 expression. Moreover, treatment of the cells with antioxidants N-acetylcysteine (NAC) and glutathione (GSH) revealed that patulin induced ATF3 expression and apoptosis were dependent on ROS generation. ATF3 expression was also increased by patulin in other colorectal cancer cell types, Caco2 and SW620. Collectively, our data present a new anti-cancer molecular mechanism of patulin, suggesting EGR-1 and ATF3 as critical targets for the development of anti-cancer chemotherapeutics. In this regard, patulin could be a candidate for the treatment of colorectal cancers.

We exploited the biological activity of an antibiotic agent asperlin isolated from Aspergillus nidulans against human cervical carcinoma cells. We found that asperlin dramatically increased reactive oxygen species (ROS) generation accompanied by a significant reduction in cell proliferation. Cleavage of caspase-3 and PARP and reduction of Bcl-2 could also be detected after asperlin treatment to the cells. An anti-oxidant N-acetyl-l-cysteine (NAC), however, blocked all the apoptotic effects of asperlin. The involvement of oxidative stress in asperlin induced apoptosis could be supported by the findings that ROS- and DNA damage-associated G2/M phase arrest and ATM phosphorylation were increased by asperlin. In addition, expression and phosphorylation of cell cycle proteins as well as G2/M phase arrest in response to asperlin were significantly blocked by NAC or an ATM inhibitor KU-55933 pretreatment. Collectively, our study proved for the first time that asperlin could be developed as a potential anti-cancer therapeutics through ROS generation in HeLa cells.

Sm 0.5 Sr 0.5 CoO 3 (SSC)–Sm 0.2 Ce 0.8 O 1.9 (SDC) core-shell composite cathodes are synthesized via a polymerizable complex method, and the durability of a cell incorporating the cathodes is examined. Nanocrystalline SSC powders have been coated onto the surfaces of SDC cores to enable the formation of a rigid backbone structure, over which the catalyst phase is effectively dispersed. A symmetrical SSC–SDC |SDC| SSC–SDC half-cell exhibits a polarization resistance of 0.098 Ω cm 2 at 650 °C. The durability and microstructure of the cathode are investigated by electrochemical impedance spectroscopy and thermo-cycle tests at temperatures in the range of 100 °C–650 °C. After 30 cycles, the polarization resistance is found to increase by 9.04 × 10 −2 Ω cm 2 , a 3.56% rise with respect to the initial resistance. Coarsening of the SSC catalyst phase has been prevented with the use of core-shell type powders, as confirmed by a nearly constant low frequency polarization resistance and a microstructural analysis. The performance of a unit cell comprised of the core-shell type cathode exhibits 1.07 W cm −2 at 600 °C and 0.62 W cm −2 at 550 °C.

In this study, 5 W class direct methanol fuel cell (DMFC) stacks using the flow field patterns of serpentine, parallel, and square spot are fabricated to compare how well they are capable of mass transport and water removal in the cathode. The stability of the stack is predicted through the simulation results of the flow field patterns on the pressure drop and the water mass fraction in the cathode of the stack. It is then estimated through the performance and the voltage distribution of the stack. According to the simulation results, although the square spot pattern shows the lowest pressure drop, the square spot pattern has much higher water mass fraction in the central region of the channel compared to the other flow field patterns. In accordance with the results, a square spot pattern for the stack-SSMA exhibits very poor water removal capabilities, leading to water flooding near the channel exit. In contrast, the performance stability of a stack-SPMA is comparable to the stack-SSMM.

A miniaturized methanol steam reformer with a serpentine type of micro-channels was developed based on poly-dimethylsiloxane (PDMS) material. This way of fabricating micro-hydrogen generator is very simple and inexpensive. The volume of a PDMS micro-reformer is less than 10 cm 3 . The catalyst used was a commercial Cu/ZnO/Al 2 O 3 reforming catalyst from Johnson Matthey. The Cu/ZnO/Al 2 O 3 reforming catalyst particles of mean diameter 50–70 μm was packed into the micro-channels by injecting water based suspension of catalyst particles at the inlet point. The miniaturized PDMS micro-reformer was operated successfully in the operating temperatures of 180–240 °C and 15%–75% molar methanol conversion was achieved in this temperature range for WHSV of 2.1–4.2 h −1 . It was not possible to operate the micro-reformer made by pure PDMS at temperature beyond 240 °C. Hybrid type of micro-reformer was fabricated by mixing PDMS and silica powder which allowed the operating temperature around 300 °C. The complete conversion (99.5%) of methanol was achieved at 280 °C in this case. The maximum reformate gas flow rate was 30 ml/min which can produce 1 W power at 0.6 V assuming hydrogen utilization of 60%.

This study examines the operating characteristics and durability of a small direct methanol fuel cell (DMFC) stack (volume: 39.6 cm 3 ). To investigate the operating characteristics in a real multi-user operating mode, various load cycles (such as gradual acceleration and deceleration), two operating modes (current mode or voltage mode) and four interrupted operating methods (load on–off, load–methanol on–off, load–air on–off, and load–methanol–air on–off) are used. The durability of the DMFC stack is examined at a constant voltage of 2.4 V (0.4 V per cell) by using the load–methanol–air on–off mode for more than 2000 h. In these tests, the DMFC stack exhibits a rapid, stable and dynamic response regardless of the load cycle and operating mode, though the stack performance and response behaviour vary with the interrupted operating modes. Among the operating modes, the air-interruption modes exhibit better stability and higher performance. Moreover, the load–methanol–air on–off mode provides the stack with good durability and a high performance in a long-term test of 2045 h.

This study investigates the enhancement of the oxygen diffusion rate at the cathode of a proton exchange membrane fuel cell (PEMFC) due to pure oscillating flow. A unit cell of PEMFC using hydrogen fuel and oscillating air was tested. The experimental results show that the non-dimensional effective diffusivity varies linearly with the square of the Womersley number, when the Womersley number is close to unity. The non-dimensional effective diffusivity varies linearly with the Womersley number itself when the Womersley number is much larger than unity. Similar trend has been confirmed from the theoretical approach. Under the experimental conditions in this study, the reaction rate of oxygen increased linearly with respect to the sweep distance. The experimental results showed that a power density of 115.4 mW/cm2 was obtained from the unit cell with oscillating flow, which is comparable to that obtained with forced flow. Therefore, an oscillating flow is found to be able to increase the concentration of the oxygen in the channel of PEMFCs, and consequently enhances mass-transfer, similarly to the use of forced flow using blowers or compressors.

To maximize power density, the volume of a fuel cell stack should be reduced by miniaturizing the stack components. In this study, thin flexible printed circuit board was utilized as a current collector in order to reduce an air-breathing monopolar stack's volume. Also, the effects of varying the geometry and opening ratios of the ports to the cathode on stack performance were evaluated in order to determine the optimal cathode structure. Use of the thin current collector and cathode port optimization resulted in an output of 3.5 W from an 18 cm 3 stack (power density of 350 mW/cm 2 ). The effects of orientation under passive air-breathing operation were determined to be nearly negligible. All data was measured at ambient pressure and temperature, baseline conditions for mobile fuel cell intended for use in consumer electronics.

Aluminium appears to be a promising material for on-board hydrogen generation in fuel cell applications given the comparatively large amount of hydrogen produced per gram of aluminium in a safe system. A microfuel processor with aluminium and water as reactants is developed in a flow reactor for application in portable power sources. Two types of reactor are used. One reactor permits the direct feeding of liquid water in channels containing aluminium pellets, whereas the other utilizes the heat produced from the reaction to vapourize liquid water before entry into the reactor. Two additives, namely, calcium oxide (CaO) and sodium hydroxide (NaOH), are used to enhance the reaction rate. A maximum conversion of 78.6% with respect to aluminium is achieved when the water entering in the reactor is vapourized partially. In the case of liquid water entering the reactor, the conversion is 74.4%.

Pore size distribution and specific pore volume in the catalyst layer of polymer electrolyte membrane fuel cells were modified by controlling the temperature during the catalyst layer fabrication. Raising the temperature of the gas diffusion layer where the platinum catalyst is coated facilitated evaporation of the solvent in the catalyst ink and induced a large pore volume especially in the secondary pore. Fuel cell electrodes with large amounts of pores exhibit 30% improved single cell performance. The microstructure and electrochemical properties of electrodes were investigated by field emission scanning electron microscopy, mercury intrusion porosimetry, electrochemical impedance spectroscopy, and current–voltage polarization measurement. The results indicate that increased volume of the secondary pore reduces the mass transfer resistance and improves the performance.

The importance of micro-fuel cell has been increased with the demand for uninterrupted power source in today's power hungry portable electronics. Currently, there is aggressive research going on to commercialize the micro-fuel cell by many laboratories and companies. The three different fuels feeding systems, i.e. pure hydrogen, pure hydrocarbons (alcohol, i.e. methanol and ethanol; formic acid and ethylene glycol) and on-board hydrogen from reformed hydrocarbons like methanol or other compound like water can be used for operating the micro-fuel cells. The current status on the research and development of micro-fuel cell with all the above three types of fuels have been discussed. The different substrate materials used in micro-fuel cells for the suitability of the portable electronics have also been stated. The design aspects of micro-fuel cells and micro-reformers are discussed here. The current state of commercialization of micro-fuel cells for portable electronics has been reviewed based on the open literature. The hurdles to overcome in order to commercialize in full phase have been reported, whenever possible. Some very new technologies which can make the micro-fuel cell into a very promising system with a simple operation have also been focused.

The operation of a micro-electro-mechanical system (MEMS)-based micro-reformer was investigated for application in a cell phone. Different aspects like the time required to attain the desired temperature of the system, the time required to get the required hydrogen flow, catalyst durability, flow uniformity of the mixture of methanol and water and volume of the total system were considered. A loading procedure for the catalyst in the micro-reformer was developed. Catalyst deactivation was observed after operating continuously for 8 h, but it regained its original activity after the reformer was shut down for at least 2 h. The deactivation of the catalyst was analyzed by catalyst characterization. The comparison of the performance between a parallel channeled and serpentine channeled micro-reformer was carried out. The performance with the serpentine channeled micro-reformer was always higher than with parallel channeled micro-reformer. The shorter residence time in the parallel-channeled micro-reformer may be one of the reasons behind its low activity.

High melt viscosity polypropylene was manufactured by grafting bifunctional monomers, HDDA (1,6-hexanediol diacrylate) and TPGDA (tripropyleneglycol diacrylate), onto homo-polypropylene under an electron beam irradiation. Melt complex viscosity (η∗) of modified polypropylene was sensitive to irradiation dose and monomer content. The melt viscosity of the polypropylene modified with TPGDA increased to 132,290 Pa s (at 190 °C and 0.1 rad/s of frequency) from 5039 Pa s for virgin homo-polypropylene. TPGDA monomer could give higher melt viscosity at low dosages than HDDA monomer, probably due to the structural feature of TPGDA with three numbers of methyl groups. Modified polypropylene with high melt complex viscosity had a broad molecular weight distribution with remarkable shift to higher molecular weight leading to high values of both M ¯ w / M ¯ n and M ¯ z / M ¯ w . Melt viscosity of modified polypropylene could be properly correlated by the equation η ∗ = k t ( M ¯ w / M ¯ n ) α ( M ¯ z / M ¯ w ) β , where the term ( M ¯ z / M ¯ w ) gave a dominant effect for the estimation of η∗.

An antiferroelectic buffer was introduced into the ferroelectric capacitors by modifying the composition of ferroelectric surfaces to minimize fatigue in the conventional Pb(Zr,Ti)O3 (PZT)-based materials with Pt electrode. The Pb(Zr,Sn,Ti)NbO3 (PZSTN) was used as antiferroelectric/ferroelectric multilayered thin films because the PZSTN has similar lattice parameters and microstructures between the antiferroelectric and ferroelectric compositions. The antiferroelectric (1 layer)/ferroelectric(5 layers)/antiferroelectric(1 layer) films showed nearly no fatigue and leakage after 109 cycles of ±10 V square pulse remaining more than 5 μC/cm2 of the switchable polarization, while the ferroelectric PZSTN (7 layers) films without antiferroelectric layers showed fatigue and significant increase of leakage current after 109 cycles. Excellent fatigue and leakage properties of the antiferroelectric/ferroelectric/antiferroelectric PZSTN films should be attributed to the antiferroelectric buffer having small stresses during 180° domain switching.

The electrical fatigue of sol-gel derived ferroelectric lead zirconate titanate (PZT 50/50) and antiferroelectric lead zirconate (PZ) thin films was found to strongly depend on the orientation and morphology. Compared to the PZT films, the PZ thin films showed a much slower degradation of polarization, due to their having less internal stress during 180° domain switching of the antiferroelectric phase. More than 70% of the initial polarization value of PZ thin films was maintained after 10 9 cycles of 15 V bipolar square pulse. The randomly oriented PZT films showed less degradation of polarization, compared to the (111) preferred PZT films. In the PZ thin films, the rosette structure with a large portion of pyrochlore phase caused severe fatigue because of nonuniform distribution of electric field and internal stress.