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Simultaneously increasing the activity and stability of the transition metal-based catalysts is critical for nonprecious metal catalysts toward oxygen reduction reaction (ORR). Herein, FeCo alloy nanoparticles encapsulated in nitrogen-doped carbon (NC) materials with surface-dangling M-Nx active sites were fabricated, and the corresponding electrocatalytic performance was carefully investigated toward ORR in both alkaline and acid media. The coexistence of M-Nx active species (Co5.47N or FeN0.0324) and FeCo alloy makes the ORR reactivity strongly enhanced compared to the counterparts with only M-Nx or FeCo species. Density functional theory calculations clearly reveal that the synergistic effect between FeCo, Fe-Nx, and NC can induce the hybridization effect between d orbitals of Fe/Co and p orbitals of N/C atoms, and thus favor the desorption of *OH intermediates. Therefore, the FeN0.0324-FeCo@NC nanocatalyst with abundant mesopores and macropores shows enhanced electrocatalytic performance in both media (E1/2 are 0.86 and 0.74 V, respectively). [ABSTRACT FROM AUTHOR]

Clear imaging of surface plasmon polaritons (SPPs) is a prerequisite for SPPs-based applications. In this work, we demonstrate an improvement of near-field imaging of SPPs via directly comparing the visibility of the photoemission electron microscopy (PEEM) image of SPPs under one- and two-color laser excitation (also known as one- or two-color laser PEEM). By measuring the photoelectron yield and the contrast of the interference fringes of SPPs, we demonstrate that in addition to enhancing the photoemission yield, two-color laser PEEM can significantly improve the contrast between bright and dark fringes (nearly 4 times higher than that of one-color laser case). By recording the nonlinear order of the photoelectrons ejected from the bright and dark fringes, respectively, the underlying mechanism for the improved visibility is revealed. In addition, the influences of the polarization direction of 400-nm laser on the PEEM images of the SPPs with different wave vector directions are shown. These results can provide technical support for the development of SPPs-based communication devices and catalysis. [ABSTRACT FROM AUTHOR]

Explicit visualization of different components of surface plasmon polaritons (SPPs) propagating at dielectric/metal interfaces is crucial in offering chances for the detailed design and control of the functionalities of plasmonic nanodevices in the future. Here, we reported independent imaging of the vertical and horizontal components of SPPs launched from a rectangular trench in the gold film by a 400-nm laser-assisted near-infrared (NIR) femtosecond laser time-resolved photoemission electron microscopy (TR-PEEM). The experiments demonstrate that distinct imaging of different components of SPPs field can be easily achieved by introducing the 400-nm laser. It can circumvent the risk of sample damage and information loss of excited SPPs field that is generally confronted in the usual NIR laser TR-PEEM scheme. The underlying mechanism for realizing distinct imaging of different components of the SPPs field with two-color PEEM is revealed via measuring the double logarithmic dependence of photoemission yield with the 800-nm and 400-nm pulse powers of different polarizations. Moreover, it is found that the PEEM image quality of the vertical and horizontal components of the SPPs field is nearly independent of the 400-nm pulse polarization. These results pave a way for SPPs-based applications and offer a possible solution for drawing a spaceâ€"time field of SPPs in three dimensions. [ABSTRACT FROM AUTHOR]

Mutations of PSEN1 have been reported in dilated cardiomyopathy pedigrees. Understanding the effects and mechanisms of PSEN1 in cardiomyocytes might have important implications for treatment of heart diseases. Here, we showed that PSEN1 was downregulated in ischemia‐induced failing hearts. Functionally, cardiovascular specific PSEN1 deletion led to spontaneous death of the mice due to cardiomyopathy. At the age of 11 months, the ratio of the heart weight/body weight was slightly lower in the Sm22a‐PSEN1‐KO mice compared with that of the WT mice. Echocardiography showed that the percentage of ejection fraction and fractional shortening was significantly reduced in the Sm22a‐PSEN1‐KO group compared with the percent of these measures in the WT group, indicating that PSEN1‐KO resulted in heart failure. The abnormally regulated genes resulted from PSEN1‐KO were detected to be enriched in muscle development and dilated cardiomyopathy. Among them, several genes encode Ca2+ ion channels, promoting us to investigate the effects of PSEN1 KO on regulation of Ca2+ in isolated adult cardiomyocytes. Consistently, in isolated adult cardiomyocytes, PSEN1‐KO increased the concentration of cytosolic Ca2+ and reduced Ca2+ concentration inside the sarcoplasmic reticulum (SR) lumen at the resting stage. Additionally, SR Ca2+ was decreased in the failing hearts of WT mice, but with the lowest levels observed in the failing hearts of PSEN1 knockout mice. These results indicate that the process of Ca2+ release from SR into cytoplasm was affected by PSEN1 KO. Therefore, the abnormalities in Ca2+ homeostasis resulted from downregulation of PSEN1 in failing hearts might contribute to aging‐related cardiomyopathy, which might had important implications for the treatment of aging‐related heart diseases. [ABSTRACT FROM AUTHOR]

A copper complex based on the pentadentate aminopyridine ligand [(9-methyl-1,10-phenanthrolin-2-yl)methyl]bis-(pyridin-2-ylmethyl)amine (Dmphen-DPA), namely [Cu(Dmphen-DPA)](ClO4)2 (1), was synthesized and characterized by elemental analysis, HR-MS spectroscopy and X-ray single crystal diffraction. The complex has five-coordinated solid-state structures, but has an open coordination site in acetonitrile. The electrochemical studies reveal that complex 1 has an electrocatalytic proton reduction activity in acetonitrile, when using acetic acid as a proton source with icat/ip ∼ 2.5. DFT calculations suggest that the parent copper complex undergoes two successive reductions to generate the radical species [Cu(I)(Dmphen-DPA˙−)]0, which is protonated at the low-valence copper center to afford a reactive CuII–H intermediate. The CuII–H species combines bimolecularly and generates H2via reductive elimination. [ABSTRACT FROM AUTHOR]

Recently, PSEN1 has been reported to have mutations in dilated cardiomyopathy pedigrees. However, the function and mechanism of PSEN1 in cardiomyopathy remains unresolved. Here, we established four types of genetically modified mice to determine the function of PSEN1 in cardiac development and pathology. PSEN1 null mutation resulted in perinatal death, retardation of heart growth, ventricular dilatation, septum defects, and valvular thickening. PSEN1 knockout in adults led to decreased muscle fibers, widened sarcomere Z lines and reduced lengths of sarcomeres in cardiomyocytes. Cardiovascular loss of function of PSEN1 induced by Sm22a-Cre or Myh6-Cre/ER/tamoxifen also resulted in severe ultrastructural abnormalities, such as relaxed gap junctions between neighboring cardiomyocytes. Functionally, cardiovascular deletion of PSEN1 caused spontaneous mortality from birth to adulthood and led to diastolic heart dysfunction, including decreased volume of the left ventricle at the end-systolic and end-diastolic stages. Additionally, in a myocardial ischemia model, deletion of PSEN1 in the cardiovascular system first protected mice by inducing adaptive hypertrophy but ultimately resulted in severe heart failure. Furthermore, a collection of genes was abnormally expressed in the hearts of cardiac-specific PSEN1 knockout mice. They were enriched in cell proliferation, calcium regulation, and so on. Taken together, dynamic regulation and abnormal function of PSEN1 underlie the pathogenesis of cardiovascular diseases due to ultrastructural abnormality of cardiomyocytes. [ABSTRACT FROM AUTHOR]

The pentadentate amine-bis(phenolate) ligand 6,6'-(dipyridin-2-ylmethylazanediyl)bis(methylene)bis(2,4-dimethylphenol) (H2L) was prepared and characterized. This ligand readily coordinates with FeIII or CoIII ions, and the resulting complexes [FeIIILCl] (1) and [CoIIIL(H2O)]Cl (2) were characterized by elemental analysis. X-ray structural studies show that the ligand in complexes 1 and 2 acts as a pentadentate ligand, leaving one coordination side of the transition metal available for exogenous ligands such as chloride ion (1) or water (2) ligand, and the central metal atoms are hexacoordinate in a similar distorted octahedral arrangement. Electrochemical studies reveal that each of the complexes exhibits multiple redox processes in the potential window investigated. Complex 1 shows one reversible oxidative event at 0.32 V and one quasi-reversible reduction event at -1.03 V, while the complex 2 displays one reversible oxidative event at 0.18 V and one quasi-reversible reduction at -0.64 V. [ABSTRACT FROM AUTHOR]

A layer-by-layer deposition strategy was employed for the immobilization of tungstophosphoric acid (HPW) onto a pentaethylenehexamine (PEHA)-grafted ZrSBA-15 framework to a give HPW/PEHA/ZrSBA-15 composite. The resulting composite was characterized by XRD, SEM, TEM, FTIR, thermogravimetric analysis, N2 sorption, and X-ray photoelectron spectroscopy, and these methods showed that the composite was stable in polar environments. These properties were attributed to the method of preparation, which ensured that a dense and stable array of HPW was encapsulated within the pores of PEHA-modified ZrSBA-15. In the H2O2-mediated oxidation of benzyl alcohol, the 25 % HPW/PEHA/ZrSBA-15 catalyst exhibited high selectivity (>99 %) for benzaldehyde. Moreover, the oxidation reaction was performed under solvent-free conditions, and the catalyst was recycled several times with negligible loss in selectivity and conversion. This HPW-based catalyst was also efficient at selectively oxidizing other benzylic and alkyl alcohols to the corresponding aldehydes. [ABSTRACT FROM AUTHOR]

Two photocatalytic hydrogen evolution systems were constructed by assembling [FeFe]-hydrogenase mimics, either carboxyl group-containing ( C1) or not ( C2), on to the surface of ZnS using triethanolamine as electron donor in DMF-H2O (9/1, v/v) solution. Upon irradiation for 30 h, the turnover numbers of hydrogen evolution were 3400 and 4950 for the hybrid system C1/ZnS and C2/ZnS, respectively. The photocatalytic activity of the C2/ZnS system was five times higher than the activity of the pristine ZnS, suggesting that the [FeFe]-hydrogenase mimics are crucial toward improving the activity of ZnS. On the basis of the spectroscopic studies and analyses, the photogenerated electron transfer from ZnS to the mimics is probably responsible for the activity enhancement of ZnS. The time dependence of hydrogen generation shows that the mimic C2 is more active than C1. The different hydrogen evolution activity can be attributed to the different adsorption modes of the two [FeFe]-hydrogenase mimics on the surface of ZnS. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] We study topological organization changes of functional connectome in ages 7–85. [•] The functional connectome exhibits linear decreases of modularity over the lifespan. [•] Both rich-club and local organization have inverted-U shaped lifespan trajectories. [•] Heterogeneous age effects are mainly localized to hub regions. [•] Connectivity reorganization over lifespan is anatomically distance-dependent. [Copyright &y& Elsevier]

A magnetically retrievable and stable composite, Fe3O4@SiO2-NH2/HPW@CS/HPW, in which H3PW12O40 (abbreviated as HPW hereafter) was successfully anchored onto the surface of a cross-linked chitosan coating on magnetic Fe3O4 cores, has been prepared by means of chemical bonding between the amino and HPW components. The resultant composites were characterized by different physicochemical techniques, such as TEM, SEM, FTIR, and vibrating sample magnetometry (VSM). An improved synthesis of methyl oleate from oleic acid and methanol was observed with the as-prepared material as catalyst with easy recovery by simply using an external magnet. A yield of 93.2 % of methyl oleate was achieved under the optimal reaction conditions, that is, a 20:1 molar ratio of methanol to oleic acid and 0.4 g catalyst at 60 °C for 4 h. It was demonstrated that improved catalytic performance and facilitated separation were simultaneously achieved in the esterification reactions as a result of the core@shell structures in which stabilized HPW and magnetic cores are integrated into one body. [ABSTRACT FROM AUTHOR]

The blue-shifted supercontinuum generation in a photonic crystal fiber pumped by high peak power femtosecond pulses with a wavelength located in the anomalous dispersion region is investigated experimentally and numerically. The formation of a blue-shifted enhanced supercontinuum due to the pulse collapse is demonstrated. The process of the pulse collapse is measured by using the grating-eliminated no-nonsense observation of ultrafast incident laser light e-fields technique (GRENOUILLE). Numerical simulations in spectral and temporal domains are conducted. The data from the numerical simulations are in good agreement with the experimental results. Our experimental results and numerical simulations show that pulse collapse is the determining factor in the generation of a blue-shifted supercontinuum. [ABSTRACT FROM AUTHOR]

Cardiac hypertrophy, which is characterized by the enlargement of cell size, reactivation of fetal genes, remains one of the most important triggers to heart failure. Increasing evidence shows that microRNA (miRNA) is extensively involved in the pathogenesis of cardiac hypertrophy. But the effects of miRNAs on cardiomyocyte hypertrophy have not been completely solved yet. Here, we showed that a collection of miRNAs was aberrantly expressed in hypertrophic cardiomyocytes induced by phenylephrine (PE) or angiotensin II (Ang II). Among them, miR-22 was the most strikingly up-regulated miRNA. To investigate the role of miR-22 in hypertrophy, both over-expression and knock-down assays were performed on cardiomyocytes. The results showed that up-regulation of miR-22 significantly increased the cell size and markedly influenced the expression of hypertrophic markers, including induction of nppa and reduction of myh6. In contrast, reduction of miR-22 level attenuated either PE- or Ang II-induced hypertrophic reaction. Furthermore, several genes, including PTEN, were identified as potential targets of miR-22 by bioinformatic algorithms. Using luciferase analysis, miR-22 could significantly suppress the luciferase activity of reporter fused with 3′ untranslated region of PTEN mRNA. Furthermore, up-regulation of miR-22 could suppress the protein level of PTEN and reduction of miR-22 level markedly increased the protein level of PTEN in cardiomyocytes by Western blot analysis, suggesting that the contribution of miR-22 to cardiomyocyte hypertrophy may be partially through targeting PTEN. Taken together, miRNAs were dynamically regulated in cardiomyocyte hypertrophy and attenuation of miR-22 in rat cardiomyocytes efficiently protected from hypertrophic effects through derepressing PTEN. J. Cell. Physiol. 227: 1391-1398, 2012. © 2011 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The preparation of Co(II) supported magnetic heterogeneous catalyst, i.e. Fe 3 O 4 @SiO 2 –NH 2 @CS–Co, and its efficient and selective catalytic properties toward the oxidation of ethylbenzene to acetophenone are presented. The materials were characterized by various physicochemical techniques such as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometer, elemental analysis, inductively coupled plasma-atomic emission spectrometer and X-ray photoelectron spectroscopy, etc. The reaction conditions were thoroughly investigated and highly improved catalytic performance (82.5% conversion of ethylbenzene and 80.1% selectivity to acetophenone) was gained under more mild reaction conditions of lower temperature (70 °C), shorter reaction period (60 min) and cheaper and greener oxygen source (H 2 O 2 ). More importantly, it could be reused successively at least 10 times when more than 80% of its catalytic activity maintained. [ABSTRACT FROM AUTHOR]

Autophagy is an adaptive response to cardiomyocytes survival under stress conditions. MicroRNAs (miRNAs, miR) have been described to act as potent modulators of autophagy. To investigate whether and how miR-199a modulated autophagy in vitro , primary cardiomyocytes were treated under starvation to induce autophagy. Results showed that down-regulation of miR-199a was sufficient to activate cardiomyocytes autophagy. MiR-199a suppressed cardiomyocytes autophagy through direct inhibiting heat shock protein family A member 5 ( Hspa5 ). Forced overexpression of Hspa5 recovered the inhibitory effect of miR-199a in autophagy activation. Our results suggested miR-199a as an effective suppressor of starvation-induced cardiomyocytes autophagy and that Hspa5 was a direct target during this process. These results extend the understanding of the role and pathway of miR-199a in cardiomyocytes autophagy, and may introduce a potential therapeutic strategy for the protection of cardiomyocytes in myocardial infarction or ischemic heart disease., Competing Interests: CONFLICTS OF INTEREST The authors declare that there is no conflicts of interest.

Exploration of the complex Ni2(MBD)4 (MBD = 2-mercaptobenzimidazole) (C1) having different coordinated Ni atoms as a photocatalyst for hydrogen evolution is made. For comparison, the bimetallic Ni2(MBT)4 (MBT = 2-mercaptobenthiazole) (C2) complex with the same coordinated Ni atoms was synthesized. Both of the complexes have been successfully constructed for photo-induced hydrogen production using organic dyes as photosensitizers and triethanolamine (TEOA) as the effective electron donor by visible light (>400 nm) in acetonitrile-water solution. The time-dependence of H2 generation and DFT computational studies demonstrate that the complex C1 is more active than C2 for H2 evolution. The mechanisms of photocatalytic hydrogen generation for C1 and C2 involve different protonation sites resulting from the differences between the two structures.