bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sub‐5 nm Pd–Ru Nanoparticle Alloys as Efficient Catalysts for Formic Acid Electrooxidation
Authors: Wu Dongshuang , Cao Minna , Shen Min , Cao Rong 
Published: May 2014

AbstractBoth Pd and Ru are important elements in electrochemistry. However, Pd–Ru nanoparticle (NP) alloys are rarely reported so far, owing to the limitations described by Hume‐Rothery. Herein, we successfully synthesized Pd–Ru NP alloys over the whole composition range using a facile atomic‐diffusion‐based strategy, and we carefully investigated the corresponding formation mechanism. For the first time, we confined the size of all alloy NPs at 3–5 nm, which is favorable in direct formic acid fuel cells. Experimental data indicate that the core‐level binding energy of Pd positively shifts as a result of electron transfer from Pd to Ru. Such an electronic effect can effectively tune the adsorption intensity of reactive molecules during electrocatalysis. Driven by all these effects, these Pd–Ru alloys are highly active and stable towards formic acid oxidation. Composition–activity study further indicates that Pd60Ru40 exhibits the best mass activity, which is 4.1 times higher than that of commercial Pd/C.
A Theoretical and Experimental Investigation of the Spectroscopic Properties of a DNA‐Intercalator Salphen‐Type ZnII Complex
Authors: Biancardi Alessandro , Burgalassi Azzurra , Terenzi Alessio , Spinello Angelo , Barone Giampaolo , Biver Tarita , Mennucci Benedetta 
Published: May 2014

AbstractThe photophysical and DNA‐binding properties of the cationic zinc(II) complex of 5‐triethylammonium methyl salicylidene ortho‐phenylenediiminato (ZnL2+) were investigated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL2+ and on its possible mono‐ and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluorescence transitions with the corresponding experimental data led to the conclusion that visible light induces a two‐electron photooxidation process located on the phenylenediiminato ligand. Kinetic measurements, performed by monitoring absorbance changes over time in several solvents, are in agreement with a slow unimolecular photooxidation process, which is faster in water and slower in less polar solvents. Moreover, structural details of ZnL–DNA binding were obtained by DFT calculations on the intercalation complexes between ZnL and the d(ApT)2 and d(GpC)2 dinucleoside monophosphate duplexes. Two main complementary binding interactions are proposed: 1) intercalation of the central phenyl ring of the ligand between the stacked DNA base pairs; 2) external electrostatic attraction between the negatively charged phosphate groups and the two cationic triethylammonium groups of the Schiff‐base ligand. Such suggestions are supported by fluorescence titrations performed on the ZnL/DNA system at different ionic strengths and temperatures. In particular, the values of the DNA‐binding constants obtained at different temperatures provided the enthalpic and entropic contributions to the binding and confirmed that two competitive mechanisms, namely, intercalation and external interaction, are involved. The two mechanisms are coexistent at room temperature under physiological conditions.
Uncatalyzed Hydroamination of Electrophilic Organometallic Alkynes: Fundamental, Theoretical, and Applied Aspects
Authors: Wang Yanlan , Latouche Camille , Rapakousiou Amalia , Lopez Colin , Ledoux‐Rak Isabelle , Ruiz Jaime , Saillard Jean‐Yves , Astruc Didier 
Published: May 2014

AbstractSimple reactions of the most used functional groups allowing two molecular fragments to link under mild, sustainable conditions are among the crucial tools of molecular chemistry with multiple applications in materials science, nanomedicine, and organic synthesis as already exemplified by peptide synthesis and “click” chemistry. We are concerned with redox organometallic compounds that can potentially be used as biosensors and redox catalysts and report an uncatalyzed reaction between primary and secondary amines with organometallic electrophilic alkynes that is free of side products and fully “green”. A strategy is first proposed to synthesize alkynyl organometallic precursors upon addition of electrophilic aromatic ligands of cationic complexes followed by endo hydride abstraction. Electrophilic alkynylated cyclopentadienyl or arene ligands of Fe, Ru, and Co complexes subsequently react with amines to yield trans‐enamines that are conjugated with the organometallic group. The difference in reactivities of the various complexes is rationalized from the two‐step reaction mechanism that was elucidated through DFT calculations. Applications are illustrated by the facile reaction of ethynylcobalticenium hexafluorophosphate with aminated silica nanoparticles. Spectroscopic, nonlinear‐optical and electrochemical data, as well as DFT and TDDFT calculations, indicate a strong push–pull conjugation in these cobalticenium– and Fe– and Ru–arene–enamine complexes due to planarity or near‐planarity between the organometallic and trans‐enamine groups involving fulvalene iminium and cyclohexadienylidene iminium mesomeric forms.
Facile Electrochemical Hydrogenation and Chlorination of Glassy Carbon to Produce Highly Reactive and Uniform Surfaces for Stable Anchoring of Thiolated Molecules
Authors: Debela Ahmed M. , Ortiz Mayreli , Beni Valerio , O'Sullivan Ciara K. 
Published: May 2014

AbstractCarbon is a highly adaptable family of materials and is one of the most chemically stable materials known, providing a remarkable platform for the development of tunable molecular interfaces. Herein, we report a two‐step process for the electrochemical hydrogenation of glassy carbon followed by either chemical or electrochemical chlorination to provide a highly reactive surface for further functionalization. The carbon surface at each stage of the process is characterized by AFM, SEM, Raman, attenuated total reflectance (ATR) FTIR, X‐ray photoelectron spectroscopy (XPS), and electroanalytical techniques. Electrochemical chlorination of hydrogen‐terminated surfaces is achieved in just 5 min at room temperature with hydrochloric acid, and chemical chlorination is performed with phosphorus pentachloride at 50 °C over a three‐hour period. A more controlled and uniform surface is obtained using the electrochemical approach, as chemical chlorination is observed to damage the glassy carbon surface. A ferrocene‐labeled alkylthiol is used as a model system to demonstrate the genericity and potential application of the highly reactive chlorinated surface formed, and the methodology is optimized. This process is then applied to thiolated DNA, and the functionality of the immobilized DNA probe is demonstrated. XPS reveals the covalent bond formed to be a CS bond. The thermal stability of the thiolated molecules anchored on the glassy carbon is evaluated, and is found to be far superior to that on gold surfaces. This is the first report on the electrochemical hydrogenation and electrochemical chlorination of a glassy carbon surface, and this facile process can be applied to the highly stable functionalization of carbon surfaces with a plethora of diverse molecules, finding widespread applications.
Synthesis of Dibenzothiophenes by Pd‐Catalyzed Dual CH Activation from Diaryl Sulfides
Authors: Che Rui , Wu Zhiqing , Li Zhengkai , Xiang Haifeng , Zhou Xiangge 
Published: May 2014

AbstractPalladium‐catalyzed dual CH functionalization of diaryl sulfides to form dibenzothiophenes (DBTs) by oxidative dehydrogenative cyclization is reported. This protocol afforded various DBTs in moderate to good yields with tolerance of a wide variety of substrates. Benzo[1,2‐b:4,5‐b′]bis[b]benzothiophene was successfully synthesized by this method, which was used as an organic semiconductor for field‐effect transistors.
Neuroanatomical characterization of a growth hormone secretagogue receptor‐green fluorescent protein reporter mouse
Authors: Mani Bharath K. , Walker Angela K. , Lopez Soto Eduardo J. , Raingo Jesica , Lee Charlotte E. , Perelló Mario , Andrews Zane B. , Zigman Jeffrey M. 
Published: May 2014

ABSTRACTGrowth hormone secretagogue receptor (GHSR) 1a is the only molecularly identified receptor for ghrelin, mediating ghrelin‐related effects on eating, body weight, and blood glucose control, among others. The expression pattern of GHSR within the brain has been assessed previously by several neuroanatomical techniques. However, inherent limitations to these techniques and the lack of reliable anti‐GHSR antibodies and reporter rodent models that identify GHSR‐containing neurons have prevented a more comprehensive functional characterization of ghrelin‐responsive neurons. Here we have systematically characterized the brain expression of an enhanced green fluorescence protein (eGFP) transgene controlled by the Ghsr promoter in a recently reported GHSR reporter mouse. Expression of eGFP in coronal brain sections was compared with GHSR mRNA expression detected in the same sections by in situ hybridization histochemistry. eGFP immunoreactivity was detected in several areas, including the prefrontal cortex, insular cortex, olfactory bulb, amygdala, and hippocampus, which showed no or low GHSR mRNA expression. In contrast, eGFP expression was low in several midbrain regions and in several hypothalamic nuclei, particularly the arcuate nucleus, where robust GHSR mRNA expression has been well‐characterized. eGFP expression in several brainstem nuclei showed high to moderate degrees of colocalization with GHSR mRNA labeling. Further quantitative PCR and electrophysiological analyses of eGFP‐labeled hippocampal cells confirmed faithful expression of eGFP within GHSR‐containing, ghrelin‐responsive neurons. In summary, the GHSR‐eGFP reporter mouse model may be a useful tool for studying GHSR function, particularly within the brainstem and hippocampus; however, it underrepresents GHSR expression in nuclei within the hypothalamus and midbrain. J. Comp. Neurol. 522:3644–3666, 2014. © 2014 Wiley Periodicals, Inc.
Intrinsic Flexibility of the Zeolitic Imidazolate Framework ZIF‐7 Unveiled by CO2 Adsorption and Hg Intrusion
Authors: Pera‐Titus Marc 
Published: May 2014

AbstractZIF‐7, built as an assembly of ZnII centers and benzimidazolate ligands, shows prominent S‐shaped isotherms upon CO2 adsorption that can be attributed to sorbate‐induced gate‐opening phenomena involving a narrow‐to‐large pore phase transition. This peculiar sorption pattern can be captured via the formulation of thermodynamic isotherms, providing a direct enthalpic and entropic view of the gate‐opening process. Relying on such an approach, an energy barrier with preferential enthalpic nature for CO2 adsorption/desorption in the gate‐opening region could be unveiled. Moreover, the elastic energy involved during the gate‐opening process was revisited to 1.4–2.8 kJ mol−1 of solid in the temperature range 273–323 K, matching the value measured by isostatic compression of a ZIF‐7_lp sample filled with DMF and showing a dominant entropic contribution.
Electrocatalytic Oxygen Reduction Reaction on Perovskite Oxides: Series versus Direct Pathway
Authors: Poux Tiphaine , Bonnefont Antoine , Kéranguéven Gwénaëlle , Tsirlina Galina A. , Savinova Elena R. 
Published: May 2014

AbstractThe mechanism of the oxygen reduction reaction (ORR) on LaCoO3 and La0.8Sr0.2MnO3 perovskite oxides is studied in 1 M NaOH by using the rotating ring disc electrode (RRDE) method. By combining experimental studies with kinetic modeling, it was demonstrated that on perovskite, as well as on perovskite/carbon electrodes, the ORR follows a series pathway through the intermediate formation of hydrogen peroxide. The escape of this intermediate from the electrode strongly depends on: 1) The loading of perovskite; high loadings lead to an overall 4 e− oxygen reduction due to efficient hydrogen peroxide re‐adsorption on the active sites and its further reduction. 2) The addition of carbon to the catalytic layer, which affects both the utilization of the perovskite surface and the production of hydrogen peroxide. 3) The type of oxide; La0.8Sr0.2MnO3 displays higher (compared to LaCoO3) activity in the reduction of oxygen to hydrogen peroxide and in the reduction/oxidation of the latter.
A Microsized Cagelike Sulfur/Carbon Composite for a Lithium/Sulfur Battery with Excellent Performance
Authors: Wang Meiri , Zhang Yining , Zhang Hongzhang , Zhang Huamin 
Published: May 2014

AbstractA sulfur/carbon composite with a hollow cagelike configuration is synthesized and employed as a lithium/sulfur battery. The material provides a hierarchical porous structure with small pores in local regions and large pores connected to each other throughout the electrode. It exhibits a good polysulfide retention ability, promotes the efficient transfer of electrons and ions, and suppresses the redistribution of active material during cycles. Thus, the battery shows an improved rate performance, as well as a superior cycling stability of 94 % capacity retention, after 100 cycles at 0.5 C.
Chitosan‐Microreactor: A Versatile Approach for Heterogeneous Organic Synthesis in Microfluidics
Authors: Basavaraju K. C. , Sharma Siddharth , Singh Ajay K. , Im Do Jin , Kim Dong‐Pyo 
Published: May 2014

AbstractMicroreactors have been proven to be efficient tools for a variety of homogeneous organic transformations due to their mixing efficiency, which results in very fast reactions, better heat and mass transfer, and simple scale‐up. However, in heterogeneous catalytic reactions each catalyst needs an individual substrate as support. Herein, a versatile approach to immobilize metal catalysts on chitosan as a common substrate is presented. Chitosan, accommodating many metal catalysts, is grafted onto the microchannel surface as nanobrush. The versatility, catalytic efficiency, and stability/durability of the microreactor are demonstrated for a number of organic transformations involving various metal compounds as catalysts.
Design and Functionalization of Photocatalytic Systems within Mesoporous Silica
Authors: Qian Xufang , Fuku Kojirou , Kuwahara Yasutaka , Kamegawa Takashi , Mori Kohsuke , Yamashita Hiromi 
Published: May 2014

AbstractIn the past decades, various photocatalysts such as TiO2, transition‐metal‐oxide moieties within cavities and frameworks, or metal complexes have attracted considerable attention in light‐excited catalytic processes. Owing to high surface areas, transparency to UV and visible light as well as easily modified surfaces, mesoporous silica‐based materials have been widely used as excellent hosts for designing efficient photocatalytic systems under the background of environmental remediation and solar‐energy utilization. This Minireview mainly focuses on the surface‐chemistry engineering of TiO2/mesoporous silica photocatalytic systems and fabrication of binary oxides and nanocatalysts in mesoporous single‐site‐photocatalyst frameworks. Recently, metallic nanostructures with localized surface plasmon resonance (LSPR) have been widely studied in catalytic applications harvesting light irradiation. Accordingly, silver and gold nanostructures confined in mesoporous silica and their corresponding catalytic activity enhanced by the LSPR effect will be introduced. In addition, the integration of metal complexes within mesoporous silica materials for the construction of functional inorganic–organic supramolecular photocatalysts will be briefly described.
Growth of Hierarchical 3D Mesoporous NiSix/NiCo2O4 Core/Shell Heterostructures on Nickel Foam for Lithium‐Ion Batteries
Authors: Zhang Qiaobao , Chen Huixin , Wang Jiexi , Xu Daguo , Li Xinhai , Yang Yong , Zhang Kaili 
Published: May 2014

AbstractWe demonstrate the facile and well‐controlled design and fabrication of heterostructured and hierarchical 3D mesoporous NiSix/NiCo2O4 core/shell nanowire arrays on nickel foam through a facile chemical vapor deposition (CVD) technique combined with a simple but powerful chemical bath deposition (CBD) technique. The smart hybridization of NiCo2O4 and NiSix nanostructures results in an intriguing mesoporous hierarchical core/shell nanowire‐array architecture. The nanowire arrays demonstrate enhanced electrochemical performance as binder‐ and conductive‐agent‐free electrodes for lithium ion batteries (LIBs) with excellent capacity retention and high rate capability on cycling. The electrodes can maintain a high reversible capacity of 1693 mA h g−1 after 50 cycles at 200 mA g−1. Given the outstanding performance and simple, efficient, cost‐effective fabrication, we believe that these 3D NiSix/NiCo2O4 core/shell heterostructured arrays have great potential application in high‐performance LIBs.
ADS‐B aided robust relay selection for cooperative communications in aircraft approach
Authors: Li Hua , Hua Cunqing , Chen Cailian , Guan Xinping 
Published: May 2014

SummaryThe ground‐to‐air communications in the aircraft approach stage suffer from multipath fading. We propose to combat this problem using cooperative communication technique. The relay selection problem is formulated to minimize the spectrum cost while preserving the signal‐to‐noise‐ratio (SNR) outage requirement of the approaching aircraft. By leveraging the position and velocity information in the automatic dependent surveillance‐broadcast messages, the average channel gains can be derived with uncertainty sets based on the Ricean channel model. Because the outage probability of the received SNR is intractable, we transform the outage constraint into a simple but efficient reliability requirement. The formulated problem is a mixed integer nonlinear optimization problem, with robustness in the worst‐case average SNR. A robust greedy relay selection algorithm is proposed as a solution, whereby a Kalman filter based trace prediction algorithm is adopted to determine the order of relays. Simulation results are given to show the effectiveness of the proposed scheme.Copyright © 2014 John Wiley & Sons, Ltd.
Sampling from social network to maintain community structure
Authors: Tong Chao , Niu Jianwei , Xie Zhongyu , Peng Fu 
Published: May 2014

SUMMARYThe research of network community structure based on a large number of complex network datasets is becoming popular in recent years. For the limit of existing computing capabilities and other conditions, such a large network data processing is becoming one of the hardest issues, so sampling algorithm research has become a new hot spot in network data analysis. Based on the needs of network structure research, in this paper, we propose an improved forest fires algorithm, which can not only decrease the scale of network data but also maintain the previous network community structure well. We define two concepts, namely ‘community degree’ and ‘center of community’ in the algorithm. Then the algorithm was applied on five datasets. In order to make it convenient for the comparison between our sampling algorithm and the other six sampling algorithms under different parameters, we use network community profile and Kolmogorov–Smirno D statistics to judge the consistency between the sample and the previous graph. Experiment results show that the improved algorithm is better than the other six sampling algorithms under most of the parameters. The efficiency and feasibility of the modified algorithm is also validated. Finally, we give the recommended values of different parameters. Copyright © 2014 John Wiley & Sons, Ltd.
Complex papillary hyperplasia of the endometrium: An uncommon case report with cytopathological features and diagnostic implications
Authors: Rekhi Bharat , Menon Santosh , Maheshwari Amita 
Published: May 2014

AbstractPapillary proliferations of the endometrium, without atypia have been uncommonly documented, including on cytology specimens. Herein, we present an uncommon case of a 55‐year‐old obese lady, on antihypertensive medications, who presented with history of irregular perimenopausal bleeding. A year ago, she was diagnosed with simple cystic hyperplasia on dilation and curettage specimen. Presently, she underwent endometrial aspiration. Cytology smears were prepared from the collected tissue specimen that was further submitted for histopathological analysis. Although the smears were initially diagnosed as negative for malignancy, the tissue sections were reported as a uterine papillary serous carcinoma (UPSC). Review of the smears revealed prominent overlapping clusters and papillary arrangements of relatively banal endometrial cells exhibiting focal metaplasia. Histopathology sections confirmed diagnosis of complex papillary hyperplasia (CPH). Immunohistochemical (IHC) stains reinforced this impression with diffuse estrogen receptor positivity, low Ki‐67/MIB1, and lack of diffuse p53 immunostaining. Subsequent hysterectomy, at the time of intraoperative consultation showed a small residual focus of CPH, restricted to endometrium with intramural leiomyomas and adenomyosis.This case is presented to highlight the fact that despite lack of significant atypia, cytological features like overlapping, clustering, and papillary formations are indicators of papillary lesions of the endometrium, including CPH, especially in postmenopausal women. On histopathology, in spite of conspicuous papillary formations, lack of significant nuclear pleomorphism, and tumor invasion are helpful features in avoiding an overdiagnosis of UPSC in such cases. IHC stains are supportive. Correct identification has significant therapeutic implications. Diagn. Cytopathol. 2015;43:163–168. © 2014 Wiley Periodicals, Inc.
Prevalence of overweight, obesity and metabolic syndrome components in children, adolescents and young adults with type 1 diabetes mellitus
Authors: Pinhas‐Hamiel Orit , Levek‐Motola Noa , Kaidar Kfir , Boyko Valentina , Tisch Efrat , Mazor‐Aronovitch Kineret , Graf‐Barel Chana , Landau Zohar , Lerner‐Geva Liat , Frumkin Ben‐David Rachel 
Published: May 2014

AbstractBackgroundWe aimed to determine the prevalence of overweight and obesity among children, adolescents and young adults with type 1 diabetes mellitus (T1DM), and to assess the prevalence of the metabolic syndrome and its components.MethodsThe study cohort comprised 326 (168 women) consecutive patients aged 5 to 30 years diagnosed with T1DM and followed up in the Juvenile Diabetes Clinic, Maccabi Health Care Services. Anthropometric measurements, blood pressure, presence of additional diseases, other medications, HbA1c, triglycerides and high density lipoprotein cholesterol levels were obtained.ResultsThe mean age in the study group was 18.5 ± 6.0 years, and the mean diabetes duration was 8.7 ± 5.0 years. Mean HbA1c level was 8.1 ± 1.3%. Nineteen per cent of the study population was overweight (85th > body mass index < 95th percentile) and 5.2% was obese (body mass index ≥ 95th percentile). Female patients aged 15 ≤ 18 and 18 ≤ 25 years were significantly overweight compared with healthy Israeli women in the same age groups, 33.3% versus 12.7% and 26.3% versus 7.8%, respectively, p < 0001. There were no obese female patients in the 15 ≤ 18 age group. Among the men in all age groups, there was no difference in the prevalence of overweight and obesity compared with healthy men in the general population. There was no difference in the age of onset, disease duration, HbA1c levels, treatment with anti‐depressants and associated morbidities between the normal weight, overweight and obese groups. Obese patients had lower levels of HDL and increased prevalence of hypertension and metabolic syndrome.ConclusionsOverweight but not obesity was more prevalent in women with T1DM. Metabolic syndrome and its components were more prevalent among overweight and obese individuals with T1DM than among normal weight individuals. Copyright © 2014 John Wiley & Sons, Ltd.