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Lianwen Zhu, Jun Wu, Qiao Zhang, Xiangkui Li, Yiming Li, Xuebo Cao
Heteroatom-doped nanoporous carbons are now emerging as alternatives to platinum and its alloys as electrocatalysts to facilitate oxygen reduction reaction in metal-air batteries and fuel cells. However, the synthesis of nanoporous carbons usually involve in complicated procedures and intensive chemicals, which may dramatically raise their manufacture cost that even surpasses that of precious platinum. Herein, we demonstrate the single-step, chemical-free fabrication of N, P dualdoped honeycomb carbon that has hierarchically porous structure and oxygen electrocatalysis activity close to the benchmark Pt/C...
August 23, 2017: Journal of Colloid and Interface Science
Vani Chandrashekar
Background: International normalized ratio (INR) derivation is dependent on the international sensitivity index (ISI) of thromboplastin. It varies with instrument and reagents used. Objective: To evaluate the role of a correction factor in the derivation of INR. Methods: We studied prothrombin time (PT) and INR from patients using 3 thromboplastins of varying ISI values. The correction factor was applied to the observed INR to obtain a corrected INR...
August 1, 2017: Laboratory Medicine
Yongguang Li, Ling Chen, Yeye Ai, Eugene Yau-Hin Hong, Alan Kwun-Wa Chan, Vivian Wing-Wah Yam
A series of amphiphilic platinum(II) complexes with tridentate N-donor ligands has been synthesized and characterized. Different supramolecular architectures are constructed using the amphiphilic molecules as the building blocks through the formation of Pt···Pt and π-π stacking interactions in aqueous media. The aggregation-deaggregation-aggregation self-assembly behavior together with obvious spectroscopic changes could be fine-tuned by the addition of THF in aqueous media. More interestingly, one of the complexes is found to show fast response and high selectivity toward alcohol and water vapors with good reversibility, leading to drastic color and luminescence changes, and hence unique dual switching behavior, with the water molecules readily displaced by the alcohol vapor...
September 21, 2017: Journal of the American Chemical Society
Jörg Exner, Gaby Albrecht, Daniela Schönauer-Kamin, Jaroslaw Kita, Ralf Moos
The pulsed polarization technique on solid electrolytes is based on alternating potential pulses interrupted by self-discharge pauses. Since even small concentrations of nitrogen oxides (NOx) in the ppm range significantly change the polarization and discharge behavior, pulsed polarization sensors are well suited to measure low amounts of NOx. In contrast to all previous investigations, planar pulsed polarization sensors were built using an electrolyte thick film and platinum interdigital electrodes on alumina substrates...
July 26, 2017: Sensors
Daniel L Young, Nancy Estocado, Du Feng, Joyce Black
Accurate assessment and clear documentation are important aspects of wound care; they provide a basis for appropriate patient care decisions and reimbursement. A descriptive, qualitative study was conducted to develop and provide preliminary evidence of the validity of a new tool to measure wound healing (the Healing Progression Rate [HPR]), a modified version of the Pressure Ulcer Scale for Healing (PUSH). Three (3) groups of current and future practitioners participated in the instrument development and evaluation process: 1) 3 wound care experts/authors (2 physical therapists, 1 nurse) with a minimum of 15 years of experience, 2) 6 additional wound care experts (4 nurses and 2 physical therapists) with a minimum of 10 years experience, and 3) 120 participants (77 [64...
September 2017: Ostomy/wound Management
Satoshi Muratsugu, Shota Miyamoto, Kana Sakamoto, Kentaro Ichihashi, Chang Kyu Kim, Nozomu Ishiguro, Mizuki Tada
A novel multiwall carbon nanotube (MWCNT) and polypyrrole (PPy) composite was found to be useful for preparing durable Pt nanoparticle catalysts of highly regulated sizes. A new pyrene-functionalized Pt4 complex was attached to the MWCNT surface which was functionalized with PPy matrix to yield Pt4 complex/PPy/MWCNT composites without decomposition of the Pt4 complex units. The attached Pt4 complexes in the composite were transformed into Pt(0) nanoparticles with sizes of 1.0-1.3 nm at a Pt loading range of 2 to 4 wt %...
September 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Muhammed Shah Miran, Tomohiro Yasuda, Ryoichi Tatara, Md Abu Bin Hasan Susan, Masayoshi Watanabe
Amphoteric water was mixed with equimolar amounts of a super-strong acid, trifluoromethanesulfonic acid (TfOH), and a super-strong base, 1,8-diazabicyclo[5.4.0]-7-undecene (DBU). Bulk physicochemical and electrochemical properties of the mixtures were compared with those of the best ever reported protic ionic liquid (PIL), diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), which has excellent physicochemical properties as a fuel cell electrolyte. The acidic mixture ([H3O][TfO]) behaved as a protic ionic liquid, while the basic mixture ([DBU]OH) showed incomplete proton transfer...
September 21, 2017: Faraday Discussions
Matthias Steimecke, Gerda Seiffarth, Michael Bron
We present a spectroelectrochemical setup, in which Raman microscopy is combined with scanning electrochemical microscopy (SECM) in order to provide both spectroscopic and electrochemical information of the very same location of an electrode at the same time. The setup is applied to a subject of high academic and practical interest, namely the oxygen evolution reaction at Ni and Ni/Fe electrodes. It comprises a transparent substrate electrode, onto which Ni and Ni/Fe thin films are deposited. An ultramicroelectrode (UME) is placed closely above the substrate to obtain electrochemical information, while a Raman microscope probes the same sample spot from below...
September 21, 2017: Analytical Chemistry
Shuiyun Shen, Xiaojing Cheng, Chao Wang, Xiaohui Yan, Changchun Ke, Jiewei Yin, Junliang Zhang
A drastic reduction of the Pt loading in the cathode catalyst layers (CCLs) of proton exchange membrane fuel cells (PEMFCs) is much desired. However, a decrease in Pt loading inevitably leads to an unexpected increase of local O2 transport resistance (rLocal) and severely weakens the fuel cell performance, particularly at high current densities. Thus, it is both urgent and meaningful to explore the impacts of the operating conditions on rLocal in CCLs and therefore to clarify the intrinsic mechanism. Herein, we systematically explore the influences of the operating conditions, in terms of the dry O2 mole fraction, the relative humidity, the operating pressure and the temperature on rLocal using limiting current measurements combined with mathematical calculations...
September 21, 2017: Physical Chemistry Chemical Physics: PCCP
Lu-Lu Ren, Hao Dong, Ting-Ting Han, Yun Chen, Shou-Nian Ding
Herein, we synthesized Pt dendrimer-encapsulated nanoparticles (Pt DENs) using amine-terminated sixth-generation polyamidoamine dendrimers. The enhanced and stable anodic electrochemiluminescence (ECL) of 3-mercaptopropionic acid-capped CdTe quantum dots (QDs) in a tripropylamine solution was achieved owing to Pt DENs. The reason may be that Pt DENs exhibit high catalytic electrochemical oxidation in the presence of tripropylamine and excellent conductive property. Inspired by this, Pt DENs were conjugated with Fe3O4@SiO2 nanoparticles and served as nano-carriers...
September 21, 2017: Analyst
Jingshan S Du, Ting Bian, Junjie Yu, Yingying Jiang, Xiaowei Wang, Yucong Yan, Yi Jiang, Chuanhong Jin, Hui Zhang, Deren Yang
Ultrafine Pt nanoparticles loaded on ceria (CeO2) are promising nanostructured catalysts for many important reactions. However, such catalysts often suffer from thermal instability due to coarsening of Pt nanoparticles at elevated temperatures, especially for those with high Pt loading, which leads to severe deterioration of catalytic performances. Here, a facile strategy is developed to improve the thermal stability of ultrafine (1-2 nm)-Pt/CeO2 catalysts with high Pt content (≈14 wt%) by partially embedding Pt nanoparticles at the surface of CeO2 through the redox reaction at the solid-solution interface...
September 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Nobuyuki Matsushita, Ayako Taira, Yoshiya Taoka
The title salt, catena-poly[[[bis-(ethyl-enedi-amine)-platinum(II)]-μ-bromido-[bis(ethyl-enedi-amine)-platinum(IV)]-μ-bromido] tetra-kis-(2-bromo-ethane-sulfon-ate) dihydrate], {[Pt(II)Pt(IV)Br2(C2H8N2)4](C2H4BrSO3)4·2H2O} n , crystallizes in the space group P21212. It has a linear chain structure extending parallel to the c axis, composed of square-planar [Pt(en)2](2+) and elongated octa-hedral trans-[PtBr2(en)2](2+) cations (en is ethyl-enedi-amine) stacked alternately and bridged by the Br atoms. The Pt site of the [Pt(II/IV)(en)2] unit is located on a general position...
July 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
Cinzia Crivellaro, Priscilla Guglielmo, Elena De Ponti, Federica Elisei, Luca Guerra, Sonia Magni, Maria La Manna, Giampaolo Di Martino, Claudio Landoni, Alessandro Buda
The aim of this study was to assess the role of 18F-FDG PET/CT in preoperative staging of vulvar cancer patients.29 pts (69 years, range 51-88) with vulvar cancer (clinical apparent stage I-II), underwent preoperative FDG-PET/CT scan followed by radical vulvectomy and bilateral (or monolateral in case of tumor >2 cm from midline) inguinal lymphadenectomy ± sentinel node biopsy. PET/CT images were analyzed in consensus and correlated to histological findings according to a pt-based and a groin-based analyses...
September 2017: Medicine (Baltimore)
Gianni Colotti, Annarita Fiorillo, Andrea Ilari
The trypanosomatid-induced diseases are considered as neglected, because the countries where they kill people are not important markets for western big pharmaceutical companies. However, recently some effort has been made to translate the use of already known drugs to neglected infectious disease. Although many metals are essential to life, many disorders affecting metal homeostasis and bioavailability are responsible for several human diseases. Metals can be toxic even at very low concentrations and semimetals are classified as toxic and dangerous for the environment...
January 1, 2018: Frontiers in Bioscience (Landmark Edition)
Nicolas Mano, Anne de Poulpiquet
Catalytic four-electron reduction of O2 to water is one of the most extensively studied electrochemical reactions due to O2 exceptional availability and high O2/H2O redox potential, which may in particular allow highly energetic reactions in fuel cells. To circumvent the use of expensive and inefficient Pt catalysts, multicopper oxidases (MCOs) have been envisioned because they provide efficient O2 reduction with almost no overpotential. MCOs have been used to elaborate enzymatic biofuel cells (EBFCs), a subclass of fuel cells in which enzymes replace the conventional catalysts...
September 20, 2017: Chemical Reviews
Zhujun Zhang, Shiliang Zhang, Qilu Yao, Xiangshu Chen, Zhang-Hui Lu
The catalytic dehydrogenation of hydrazine borane (N2H4BH3) and hydrous hydrazine (N2H4·H2O) for H2 evolution is considered as two of the pivotal reactions for the implementation of the hydrogen-based economy. A reduction rate controlled strategy is successfully applied for the encapsulating of uniform tiny NiPt alloy nanoclusters within the opening porous channels of MOFs in this work. The resultant Ni0.9Pt0.1/MOF core-shell composite with a low Pt content exerted exceedingly high activity and durability for complete H2 evolution (100% hydrogen selectivity) from alkaline N2H4BH3 and N2H4·H2O solution...
September 20, 2017: Inorganic Chemistry
Meiqin Shi, Xue Tong, Wang Li, Jun Fang, Li-Tao Chen, Chun-An Ma
The continuous solid solution NiWOx is successfully prepared by using precursor W18O49 with plenty of oxygen defects. The NiWOx nanoparticles are characterized by X-ray diffraction, High resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The crystallographic phase of NiWOx is stable and characterized by the same feature of the parent lattice W18O49 even with various concentration of dopant Ni which indicates the existence of oxygen defects. The NiWOx nanoparticles could be processed as the appropriate promoter after loading 10 wt% Pt...
September 20, 2017: ACS Applied Materials & Interfaces
Octavian D Pavel, Iunia Podolean, Vasile I Parvulescu, S F Rebecca Taylor, Haresh G Manyar, Kathryn Ralphs, Peter Goodrich, Christopher Hardacre
This study reports the behaviour of SCILL based catalysts in the oxidative S-S coupling of aliphatic and aromatic thiols, namely 1-butanethiol and thiophenol, to dibutyl disulfide and diphenyl disulfide. A range of ionic liquids (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide) and metal supported catalysts (5% Pt/SiO2; 5% Ru/SiO2; 5% Ru/C; 5% Pt/OMS-2) were used to prepare the SCILL catalysts and all were found to be active for the reaction following the trend 5% Pt-OMS-2 > 5% Pt/SiO2 > 5% Ru/C > 5% Ru/SiO2...
September 20, 2017: Faraday Discussions
Jorge Quintero-Saumeth, David A Rincón, Markus Doerr, Martha C Daza
We have carried out a computational study on the reactivity of catechol (1,2-dihydroxybenzene) towards superoxide radical anion (O2˙(-)) in water, N,N-dimethylformamide (DMF), pentyl ethanoate (PEA) and vacuum using density functional theory and the coupled cluster method. Five reaction mechanisms were studied: (i) sequential proton transfer followed by hydrogen atom transfer (PT-HT), (ii) sequential hydrogen atom transfer followed by proton transfer (HT-PT), (iii) single electron transfer (SET), (iv) radical adduct formation (RAF) and (v) concerted double proton-transfer electron-transfer (denoted as global reaction, GR)...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
Tatsuya Iwata, Kyosuke Matsuda, Kazuhiro Takahashi, Kazuaki Sawada
Demand for the detection of carbon dioxide (CO 2 ) is increasing in various fields, including air-quality monitoring, healthcare, and agriculture. On the other hand, smart gas sensors, in which micromachined gas sensors are integrated with driving circuits, are desirable toward the development of the society of the internet of things. In this study, micromachined hotplate-based CO 2 sensors were fabricated and their characteristics were investigated. The sensors have La 2 O 3 /SnO 2 stacked layers as a sensing material and Pt interdigitated electrodes...
September 20, 2017: Sensors
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