bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microporous lanthanide metal-organic frameworks
Authors: Chen Yao , Ma Shengqian 
Published: August 2012

AbstractMicroporous metal-organic frameworks (MOFs) based on lanthanide metal ions or clusters represent a group of porous materials, featuring interesting coordination, electronic, and optical properties. These attractive properties in combination with the porosity make microporous lanthanide MOFs (Ln-MOFs) hold the promise for various applications. This review is to provide an overview of the current status of the research in microporous Ln-MOFs, and highlight their potential as types of multifunctional materials for applications in gas/solvent adsorption and separation, luminescence and chemical sensing and catalysis.
Effects of sugar cane bagasse ash as a cement replacement on properties of mortars
Authors: Chi Mao-Chieh 
Published: August 2012

AbstractSugar cane bagasse ash (SCBA), a by-product of sugar and alcohol production, is one of the potential pozzolanic material that can be blended with Portland cement. In this study, SCBA with particle sizes <45 μm was used to replace type I ordinary Portland cement with various dosages (10%, 20%, and 30%) by weight of binder. The water/cementitious material (w/cm) and sand/binder ratios were kept at constants of 0.55 and 2.75, respectively. Composites were mixed, and effects of SCBA on properties were investigated by conducting flow test, water absorption test, initial surface absorption test, drying shrinkage test, compressive strength test, rapid chloride penetration test (RCPT), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Experimental results show that the flow spread of fresh mortars would decrease with an increase of SCBA replacement. The specimens with 10% SCBA have the superior performance on compressive strength, drying shrinkage, water absorption, initial surface absorption, and chloride ion penetration, TGA, and SEM at the age of 56 days. It indicates that 10% cement replacement of SCBA may be considered as the optimum limit.
Estimation of fracture energy of high-strength steel fibre-reinforced concrete using rule-based Mamdani-type fuzzy inference system
Authors: Köksal Fuat , Şahin Yuşa , Beycioğlu Ahmet , Gencel Osman , Brostow Witold 
Published: August 2012

AbstractIn this study, we worked to estimate the fracture energy of steel fibre-reinforced concrete (SFRC) according to the water/cement ratio (w/c), tensile strength of steel fibre, steel fibre volume fraction and flexural strength of concrete sample as inputs using the Mamdani-type fuzzy inference system (FIS). In the study, the values obtained from the model and experimental divided three groups (each group has six experimental results) according to the w/c ratios to evaluate the fuzzy logic (FL) model approximate reasoning ability. As a result, the Mamdani-type FIS has shown a satisfying relation with the experimental results and suggests an alternative approach to evaluate the fracture energy estimation using related inputs.
Effects of electromagnetic absorption toward a human head due to variation of its dielectric properties at 900 and 1900 MHz with different antenna substrates
Authors: Husni Nur Aisyah , Faruque Mohammad Rashed Iqbal , Islam Mohammad Tariqul , Misran Norbahiah , Mohamed Nik Abdullah Nik 
Published: August 2012

AbstractThe aim of this paper is to analyze the effects of electromagnetic (EM) energy absorption at 900 and 1900 MHz when the human head’s dielectric properties are varied. This radiation is measured in terms of specific absorption rate (SAR). The characteristics of the helical antenna and its substrates with variation of the human head dielectric properties were simulated via the finite-difference time domain (FDTD) method using the CST Microwave studio. The human head dielectric properties are manipulated by increasing and decreasing 10% and 20% of each dielectric property. In this study, SAR values increase with increase of the human head’s conductivity, while increase of permittivity and densities decreases it. A helical antenna with a substrate of FR4 resulted in higher SAR values in all frequencies. The head SAR values are higher in the upper frequency exposures. The helical antenna with a substrate of Rogers RO3006 (loss free) was found to be the best-tested substrate, which contributed toward much lower SAR values in all GSM frequency bands.
The Clinical Features of Hand‐arm Vibration Syndrome in a Warm Environment—A Review of the Literature
Authors: Su Anselm Ting , Darus Azlan , Bulgiba Awang , Maeda Setsuo , Miyashita Kazuhisa 
Published: August 2012

The Clinical Features of Hand‐arm Vibration Syndrome in a Warm Environment—A Review of the Literature: Anselm Ting SU, et al. Centre for Occupational and Environmental Health, University of Malaya, Malaysia—The internationally Accepted limit values and the health effects of hand‐transmitted vibration exposure have been described extensively in the literature from temperate climate countries but not from a tropical climate environment.ObjectivesWe conducted a systematic review of the health effects of hand‐transmitted vibration exposure in tropical countries to determine the characteristics of hand‐arm vibration syndrome in a warm environment and compared the findings with the results of the systematic reviews published by the US NIOSH.MethodsWe searched major medical databases including MEDLINE, PubMed, Embase, CINAHL, Ovid and Cochrane based on the terms “hand arm vibration syndrome,” “hand transmitted vibration,” “vibration white finger” and “Raynaud” up to January 2011. Only studies conducted in a tropical or subtropical environment were selected for the review. The quality of the selected papers was assessed independently by two investigators using predefined criteria. A standard set of information was abstracted from the papers for review.ResultsOnly six papers from tropical countries and three papers from subtropical countries were available in the literature. No vibration white finger was reported in the tropical countries. Neurological symptoms were prevalent in the vibrationexposed workers. Finger coldness seems to be an important surrogate for vascular disorder in a tropical environment. Meta‐analysis could not be performed due to inadequacy of the information reported in these papers.ConclusionsThe current dose‐response relationship in ISO5349‐1 for hand‐transmitted vibration exposure is not applicable to a tropical environment. Further studies on hand‐arm vibration syndromes in tropical countries are needed.
Do Former Audit Firm Partners on Audit Committees Procure Greater Nonaudit Services from the Auditor?
Authors: Naiker Vic , Sharma Divesh S. , Sharma Vineeta D. 
Published: August 2012

ABSTRACT:
To address potential threats to auditor independence, the Sarbanes-Oxley Act of 2002 (SOX) requires the audit committee to pre-approve nonaudit services (NAS) procured from the auditor. However, the presence of a former audit firm partner (FAP) affiliated with the current auditor on the audit committee could undermine the audit committee's due diligence over the NAS pre-approval process. To alleviate such concerns, the Securities and Exchange Commission approved a three-year “cooling-off” period for appointing audit firm alumni as independent directors. Our analyses show that the presence of both affiliated and unaffiliated FAPs on audit committees does not lead to greater NAS procured from the auditor; rather, FAPs reduce NAS procured from the auditor. Moreover, NAS decline significantly following the appointment of FAPs to the audit committee. Further tests suggest the three-year cooling-off period may not be warranted and deserves further investigation. Our study raises important implications for regulators, policy makers, corporate boards, and future research.
Data Availability: Data are publicly available from sources identified in the text.
Planen in einer spontanen Ordnung (Essay)
Authors: Hostettler Martin 
Published: August 2012

Planning in a spontaneous order (essay)
Planning is necessary for certain public activities. In land use planning and environmental planning very different instruments come into use, the description of which frequently cannot be directly related to the public activity planned. Four achievements in coordination can be attributed to land use and environmental planning. The most important consists in the creation of a consensus, since the Tragedy of the Anticommons can thus be mitigated. The supply of valuable goods is still controversial, since this takes place both by means of procurement and by regulation. Planning in a spontaneous order can only make adjustments, which is why it is wise to proceed with prudence and modesty.
Differentiation and Characterization of Dendritic Cells from Human Embryonic Stem Cells
Authors: Mohib Kanishka , Wang Lisheng 
Published: August 2012

AbstractHuman embryonic stem cells (hESCs) offer great hope in regenerative medicine. Their ability to give rise to almost any type of cell present in the adult body makes them an invaluable tool in finding cures for a variety of diseases. While considerable protocols have been devised to efficiently differentiate hESCs into various cells types including cells of hematopoietic origin, this protocol will focus on the derivation of dendritic cells (DC), a potent antigen‐presenting cell. DCs are a highly important arm of the immune system, as they represent one of the few cells that bridge the innate and adaptive systems, leading to effective pathogen clearance. The study of DCs has led to potential applications in diverse fields, such as vaccine development, tumor immunology, and transplantation. In this protocol, we describe two different methods of differentiating hESCs into DCs. The first method uses OP9 bone marrow stromal supporting cells as a coculture system, while the second method utilizes the formation of embryoid body (EB, cellular aggregate) as an approach. To assure the successful outcome and subsequent assessment of the differentiated DCs, supporting protocols have been included in this chapter. Curr. Protoc. Immunol. 98:22F.11.1‐22F.11.22. © 2012 by John Wiley & Sons, Inc.
Palladium‐Catalyzed Aerobic Oxidative Coupling of Acyl Chlorides with Arylboronic Acids
Authors: Chen Jiuxi , Peng Yong , Liu Miaochang , Ding Jinchang , Su Weike , Wu Huayue 
Published: August 2012

AbstractThe first example of a palladium‐catalyzed aerobic oxidative coupling of acyl chlorides with arylboronic acids has been developed, leading to a wide range of aryl benzoates in good to excellent yields. This catalytic system shows broad functional group tolerance. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from dioxygen.
Selective para‐Cyanation of Alkoxy‐ and Benzyloxy‐Substituted Benzenes with Potassium Ferricyanide Promoted by Copper(II) Nitrate and Iodine
Authors: Ren Yunlai , Yan Mengjie , Zhao Shuang , Wang Jianji , Ma Junying , Tian Xinzhe , Yin Weiping 
Published: August 2012

AbstractA simple method was developed for selective para‐cyanation of alkoxy‐ and benzyloxy‐substituted benzenes with 0.5 equivalents of potassium ferricyanide, 0.8 equivalants of copper(II) nitrate and 0.5 equivalents of iodine in acetonitrile. Among various phenyl carbon‐hydrogen bonds, those at the para‐position with regard to the alkoxy or benzyloxy groups were selectively cyanated in 20% to 87% yields (23 examples). The present method uses commercially available reagents, and can be performed on a ten gram‐scale. Interestingly, methoxybenzene was cyanated in 32% yield in the absence of potassium ferricyanide, which suggests that the nitrile group of a part of the product is possibly from the solvent acetonitrile.
Asymmetric Brønsted Acid‐Catalyzed Nazarov Cyclization of Acyclic α‐Alkoxy Dienones
Authors: Raja Sadiya , Ieawsuwan Winai , Korotkov Vadim , Rueping Magnus 
Published: August 2012

AbstractA Brønsted acid‐catalyzed asymmetric Nazarov cyclization of acyclic α‐alkoxy dienones has been developed. The reaction offers access to chiral cyclopentenones in a highly enantioselective manner. The reaction is complementary to our previously reported Brønsted acid‐catalyzed electrocyclization reactions, which provided differently substituted optically active cyclopentenones with a fused tetrahydropyrane ring in good yields and with excellent enantioselectivities.
Energieumwandlung in chemischen Verfahren
Authors: Riekert Lothar 
Published: August 2012

AbstractAlle chemischen Verfahren lassen sich als Prozesse der Energieumwandlung auffassen. Die Elementarzusammensetzung der Materie bleibt bei chemischen Prozessen insgesamt unverändert, jedoch ist die maximale mechanische Arbeit, die sich bestenfalls aus den Ausgangsstoffen gewinnen ließe (deren sog. Exergie) nach dem 2. Hauptsatz notwendig größer als das entsprechende Arbeitsäquivalent der Produkte. Diese maximale potentielle Arbeit als universelles Maß des nutzbaren Teiles aller Energien kann in sinnvoller Weise nur in Bezug auf einen festgelegten Umgebungszustand definiert werden, der durch den stationären Zustand unserer Umwelt bestimmt ist. — Auf der Grundlage des zweiten Hauptsatzes der Thermodynamik kann man danach den thermodynamischen Wirkungsgrad von Produktionsverfahren oder von Prozessen berechnen, die der Speicherung von Energie dienen sollen. Durch eine fortschreitende Unterteilung des Bilanzraumes läßt sich weiterhin ermitteln, welche Teilvorgänge besonders verlustreich sind. Eine Betrachtung einiger großtechnischer verfahren zeigt, mit welchen Mitteln es gelingt, deren thermodynamischen Wirkungsgrad zu verbessern und welche Grenzen diesem Bemühen gesetzt sind. — Irreversible Vorgänge sind Exergiesenken; Exergieverbrauch und Entropieproduktion sind einander proportional. Exergiequellen im geschlossenen System unserer Geosphäre beruhen auf Vorgängen, die mit dem externen Strahlungsenergieaustausch gekoppelt sind.
Physikalisch‐chemische Probleme bei der Erzeugung und Speicherung chemischer sekundärer Energieträger
Authors: Stucki S. , Menth A. 
Published: August 2012

AbstractWasserstoff ist als sekundärer Energieträger universell einsetzbar. Die Erzeugung von Wasserstoff aus Wasser und nichtfossiler Energie ist bereits mit heutiger Technik möglich. Der Wirkungsgrad der Elektrolyse muß verbessert und die Anlagekosten gesenkt werden. — Am Beispiel Membran‐Elektrolyse werden die Probleme bei der Entwicklung einer neuen Technik beschrieben. Wesentliche Bedeutung kommt der Elektrokatalyse der Sauerstoffentwicklung zu. Wichtig für eine wirtschaftliche Prozeßführung ist eine hohe Energieumwandlungsdichte. Wasserstoffproduktion in thermochemischen Zyklen bringt eine Reihe von verfahrenstechnischen und Materialproblemen. Die technische Realisierung dieser Zyklen erscheint fragwürdig. — Große Bedeutung kommt bei der Nutzung von H2 als Sekundärenergieträger dessen Speicherung zu. Es wird zwischen stationärer Speicherung großer Kapazität und mobiler Speicherung unterschieden.
Untersuchungen über den Mechanismus und die Katalyse der kathodischen Sauerstoffreduktion an verschiedenen Metallen
Authors: Fabjan Ch. , Kazemi M. R. , Neckel A. 
Published: August 2012

AbstractDie Kinetik und Katalyse der kathodischen Sauerstoffreduktion wurden an glatten Pd‐, Ag‐, Au‐, Fe‐, Co und Ni‐Elektroden in alkalischen (KOH), an Pd auch in schwefelsauren Elektrolyten untersucht. Die kathodische Reaktionsordnung (RO) bezüglich des Partialdruckes von Sauerstoff beträgt an Pd, Ag und Au + 1 an Fe, Co und Ni dagegen + 0,5. Daraus folgt, daß im ersten Fall die Reduktion des Sauerstoffes im Durchtrittsbereich direkt zu Hydroxidionen bzw. Wasser führt, wahrend im zweiten Fall (RO = +0,5) ausschließlich Peroxid bzw. Perhydroxylanion gebildet wird. — Hinsichtlich der Hydroxidionenkonzentration werden — mit Ausnahme von Ni — negative kathodische R.O. gefunden; dies wird auf die zunehmende spezifische Adsorption von OH− ‐lonen mit wachsender Alkalität zurück‐geführt. Ferner ist die mit steigender Elektrolytkonzentration abnehmende Löslichkeit des Sauerstoffes zu berücksichtigen. — Die elektrokatalytische Aktivität der Elektrodensubstrate nimmt in der Reihenfolge Fe < Ni < Au < Ag < Co(Pd) < Pd(Co) zu.
The Applicability of Semiconducting Layered Materials for Electrochemical Solar Energy Conversion
Authors: Kautek W. , Gobrecht J. , Gerischer H. 
Published: August 2012

AbstractSemiconducting transition metal dichalcogenides with layer structure belong to the most stable electrode materials in electrochemical solar cells. The photoelectrochemical reactions however, are complicated by the surface anisotropy. Results of photoelectrochemical cells with n‐type MoSe2 and WSe2 demonstrate the importance of surface morphology for the energy conversion efficiency. — The optimal energy conversion yield of these layered semiconductors has turned out being lower than theoretically expected from their band gaps. It is shown that this is connected with the existence of an indirect band gap which restricts light absorption in a considerable energy quantum range above the band gap. Besides this, surface defects and inhomogeneities reduce the quantum yield by increased surface recombination. — Photoelectrochemical hydrogen evolution has been investigated with p‐type WSe2. It is shown that a considerable energy gain can be reached by the catalytic action of platinum deposits on the surface of the electrode. This is explained in terms of surface state catalysis.
Wasserstoff als Energieträger und seine Darstellung mittels Schmelzflußelektrolyse
Authors: Dorner S. , Schretzmann K. 
Published: August 2012

AbstractDie Bedeutung des Wasserstoffs als künftiger Energieträger, vor allem im Straßenverkehr, wird herausgearbeitet. Er kann in Verbrennungsmotoren direkt verwendet werden. Eine besonders gute Nutzung des Wasserstoffs ist in Brennstoffzellen möglich. — Überlegungen über die Darstellung von Wasserstoff durch chemische Kreisprozesse haben gezeigt, daß es notwendig ist, elektrochemische Teilschritte einzuführen. Günstige Voraussetzungen sind bei der elektrolytischen Zersetzung von geschmolzenen Cäsiumsalzen gegeben. Das abgeschiedene Cäsium wird zur Wasserstofffreisetzung aus Wasser verwendet. Gedankliche Ansätze zur Ausgestaltung des Verfahrens werden vorgelegt. Auf die offenen Fragen der Cäsiumchemie wird hingewiesen.
2‐(2‐Pyridinyl)‐1‐(3‐Pyridinyl)‐Ethanone — Structure and Spectroscopic Properties
Authors: Melzig M. , Schneider S. , Dörr F. , Daltrozzo E. 
Published: August 2012

AbstractReaction of 2‐methylpyridyl lithium with ethyl pyridine‐3‐carboxylate yields 2‐(2‐pyridinyl)‐1‐(3‐pyridinyl)‐ethanone, which occurs in solution as three tautomers. The dependence of the tautomeric equilibria on both the solvent and the temperature is determined by means of 1H‐n.m.r., electronic absorption and electronic emission spectra. The correlation between tautomeric structures and u.v. spectra is supported by the results of quantum mechanical model calculations in the PPP approximation. — The dependence of the fluorescence on both the solvent and the temperature is interpreted in terms of solvent cage effects as well as rapid intramolecular and/or intermolecular hydrogen exchange.
Photoinduced Electron Transfer between Amphipathic Ruthenium(II) Complex and N‐Butylphenothiazine in Various Microenvironments
Authors: Takayanagi Takashi , Nagamura Toshihiko , Matsuo Taku 
Published: August 2012

AbstractElectron transfer between photoexcited amphipathic ruthenium(II) complex and N‐butylphenothiazine in various microenvironments such as acetonitrile, micelles, synthetic bilayers, and phospholipid liposomes was studied by the flash photolysis. Back electron transfer reactions were appreciably retarded when the reaction proceeded in the vicinity of charged surface of surfactant molecular assemblies. The increase of temperatures resulted in the decrease of the back electron transfer rate constant (kd) in micelles and synthetic bilayers, whereas kd‐value increased with temperatures in a homogeneous acetonitrile solution. These results were explained as due to microenvironmental effects on diffusion of photogenerated redox species.
Über die Beobachtung von Phosphoreszenz und verzögerter Fluoreszenz am Dikation BH2+2 des Betains B
Authors: Finkentey Johann‐Henrich , Zimmermann Herbert W. 
Published: August 2012

AbstractAbsorptions‐, Emissions‐ und Polarisationsgradspektren des Dikations D = BH2+2 von Betain B wurden bei — 195°C in glasartig erstarrter alkoholischer Lösung gemessen. Aus der Diskussion der Spektren wurde geschlossen, daß D neben der Phosphoreszenz noch eine verzögerte Fluoreszenz emittiert. Die Übergangsmomente von verzögerter Fluoreszenz und Phosphoreszenz stehen annähernd senkrecht aufeinander.
Occupation Numbers in Micellar Solubilisation — An Excimer Study
Authors: Miller D. J. , Klein U. K. A. , Hauser M. 
Published: August 2012

AbstractKinetic fluorescence spectroscopy can give important information on micellar solubilisation. The kinetics of excimer formation of pyrene in aqueous Na‐dodecylsulphate solution show that there are discontinuous occupation numbers which can be described by the Poisson distribution. The micellar aggregation number g(I, T) increases with ionic strength to over 200 and diminishes with temperature. The temperature dependence of g(I, T) was measured at several Na2SO4 concentrations
Dimerization Equilibria of Aromatic Radical Cations
Authors: Kotowski S. , Grabner E. W. , Brauer H.‐D. 
Published: August 2012

AbstractIt is demonstrated that for the system perylene in butyronitril, the dimerization equilibria of radical cations R+ + R ⇌ R+2 (I) and 2R+ ⇌ R++2 (II), occur simultaneously. In order to determine thermodynamic data, the complex system can be divided in simple subsystems by employing the property that one component, the radical cations, is generated electrolytically. Thus from the derivative of the absorbance A with respect to the charge q consumed at q = 0, (dA/dq)q=0, the parameters of equilibrium I are obtained: −ΔH+ = (36 ± 6) kJ/mol, −ΔS+ = 71 ± 8) J/mol · K. The temperature variation of a nearly totally electrolyzed solution enables the determination of the parameters of equilibrium II: −ΔH++ = (45 ± 2) kJ/mol, −ΔS++ = (76 ± 8) J/mol · K. For equilibrium I the influence of the follow‐up reaction of perylene radical cations with traces of water could be described quantitatively (pseudo first‐order rate constant −2 · 10−3 s−1).
A Voltammetric Analysis of the Electrochemical Behaviour of Onium Salts at a Mercury Electrode
Authors: Hall Elizabeth A. H. , Horner Leopold 
Published: August 2012

AbstractAn analysis of the cyclic voltammograms of the reduction of various onium salt at mercury, produced more detailed information concerning the nature of the reaction pathway, in terms of adsorption, amalgam formation and kinetics of electron transfer, and lead to an interpretation of the characteristic “inverted peak”. An “auto‐catalytic” reaction mechanism was indicated, and in conjunction with the preparative experiments [1, 2] a full reduction scheme proposed for the sulphonium salt ([Ph2S+ CH3)]CIO−4) and the phosphonium salt ([Ph2P+ (CH3)2]Br−).