bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel method of network function analysis based on the Andreani–Mattisson extension to the Cochrun–Grabel algorithm
Authors: Fontana Giuseppe 
Published: November 2013

SummaryKnowing the Network Function (NF) pertaining to a certain input–output couple individuated inside a linear electrical network (LEN) is crucial, as it provides a synthetic and effective description of the input–output relationship and allows one to derive several key features of the subject system as well as to devise proper strategies to modify them.From a mathematical point of view, an NF may be expressed as the product of a real number, called the gain constant (GC), by a real rational function of the complex variables, whose numerator and denominator are called the zero polynomial (ZP) and the characteristic polynomial (CP), respectively, and may be obtained by calculating the determinants of proper matrices. However, when a design‐oriented symbolic hand analysis is needed, calculating the said polynomials in this manner may turn out to be tediously cumbersome; and above all, such a route may fail to illuminate the way that their coefficients depend on the circuit elements. The same may be said of numerical computer methods, which are suited to providing a global description of the NF in the frequency domain rather than analytical expressions of its coefficients. In this paper, a method is proposed that permits one to obtain the ZP without calculating any determinants. With respect to other methods that achieve the same goal, the present one does not require prior calculation of the CP or a nullator‐norator pair (NNP) to be compulsorily inserted in the subject circuit. Instead, it is based on applying the Andreani‐Mattisson extension (AME) of the Cochrun–Grabel algorithm (CGA) for the calculation of the CP to a circuit obtained from the assigned one by inserting in the latter a proper dependent source. The nature of such new circuit allows the worker to employ the classical tools of LEN theory so as to make the analysis as simple as possible and often performable by straightforward inspection, without the need for possibly involved equilibrium equations. Moreover, it is shown how the same technique can be applied to a properly modified version of the original network in order to calculate the CP as well. In this case (not compulsorily but if judged convenient for simplifying the calculations), a NNP may be employed in conjunction with the dependent source. The proposed method once again allows one to exploit the classic tools of LEN theory so as to considerably, if not drastically, simplify the analysis associated with the direct application of the AME to the original network. Finally, the calculation of the GC (that completes the knowledge of the whole NF under study) as well as circuit degeneracy are discussed and practical examples of application of the proposed techniques are given. Copyright © 2013 John Wiley & Sons, Ltd.
Rhodamine‐Based Chromo‐/Fluorogenic Dual Signalling Probe for Selective Recognition of HgII with Potential Applications for INHIBIT Logic Devices and Cell‐Imaging Studies
Authors: Mistri Tarun , Alam Rabiul , Dolai Malay , Kumar Mandal Sushil , Guha Pratik , Rahman Khuda‐Bukhsh Anisur , Ali Mahammad 
Published: November 2013

AbstractA new rhodamine‐based dual signaling probe (L3) has been found to display quick responses through visible colorimetric changes as well as fluorogenic properties on selective 1:1 binding to Hg2+, as delineated by absorption and fluorescence titrations as well as by Job′s method and ESI‐MS+ studies. The fluorescent probe L3 displays a 252‐fold fluorescence enhancement on binding to Hg2+. A Benesi–Hilderband fit of the absorption titration data gives Kd = (32.01 ± 0.74) μM and a 1:1 binding stoichiometry. Owing to its solubility in mixed organic/aqueous solvents as well as its cell permeability, L3 could be used for in vitro/in vivo cell imaging of Hg2+ with no or negligible cytotoxicity. The detection limit of Hg2+ was calculated by the 3σ method to be 9.28 ng L–1. Moreover, the fluorescence of the L3–Hg2+ system was turned off and its red colour disappeared when KI was added. Thus, the “OFF–ON–OFF” fluorescence sensing behaviour of L3 observed in the presence of Hg2+ and I– may find applications in devices with logic gate functions.
Molecular and Polymeric Uranyl and Thorium Complexes with Sulfonate‐Containing Ligands
Authors: Thuéry Pierre 
Published: November 2013

AbstractSix uranyl and one thorium(IV) cation complexes with ligands involving either only sulfonate or both sulfonate and carboxylate groups as complexing sites were obtained, mainly under hydrothermal conditions, and their crystal structures were determined. The uranyl ion complex with the 2‐sulfobenzoate (2‐SB2–) anion synthesized in the presence of pyridine, [pyH]4[(UO2)2(2‐SB)2O]2·4H2O (1), is a molecular, tetranuclear complex in which 2‐SB2– is chelating through its two functional groups, while [Th(2‐SB)2(H2O)3]·2H2O (2) is a 1D polymer with monodentate sulfonate and bridging bidentate carboxylate groups. Complex [(UO2)3K(4‐SB)O(OH)3(H2O)1.5]·0.5H2O (3), with the 4‐sulfobenzoate ligand, crystallizes as a 3D framework in which uranyl oxo/hydroxo 1D subunits are connected to one another by 4‐SB2– and potassium cation bridges, the latter being involved in as much as five bonds with uranyl oxo groups (“cation–cation” bonds). Complex [UO2(5‐SSH2)(H2O)3]2·2(5‐SSH2)·3H2O (4), with 5‐sulfosalicylic acid (5‐SSH3), is a dinuclear species in which the ligand is only coordinated through its bridging bidentate sulfonate group, an unusual occurrence. 5‐Sulfosalicylic acid undergoes partial desulfonation and carboxylation under hydrothermal conditions, yielding the heterometallic, tetranuclear complex [UO2Ni(5‐SHIPH)(4‐HIPH2)(bipy)2(H2O)]2·(4‐HIPH3) (5), 5‐sulfonato‐2‐hydroxyisophthalic acid (5‐SHIPH4) and 4‐hydroxyisophthalic acid (4‐HIPH3) being generated in situ. The all‐sulfonate ligand 1,2‐ethanedisulfonate (EDS2–) acts as a divergent linker in both [UO2(EDS)(H2O)3] (6) and [(UO2)2(EDS)(OH)2(phen)2]·4H2O (7). 1D polymers are formed in both cases, the doubly monodentate EDS2– ligand bridging isolated uranyl ions in 6 or hydroxo‐bridged uranyl dimers in 7. Sulfonate coordination to the 5f cation is present in all these complexes but 5, even in the absence of synergistic effects exerted by the stronger carboxylate ligating groups, and the variety of structures obtained in this as well as in previous work demonstrates that, together with the more investigated phosphonates, sulfonates are anions of great potential for the synthesis of actinide–organic coordination polymers and frameworks.
Formation of 1,3‐Diphosphacyclobutadiene Complexes from Phosphaalkynes and Their Coordination Behavior
Authors: Rummel Eva‐Maria , Eckhardt Maria , Bodensteiner Michael , Peresypkina Eugenia V. , Kremer Werner , Gröger Christian , Scheer Manfred 
Published: November 2013

AbstractBy using [(Cp″′Co)2tol] (Cp″′ = η5‐C5H2tBu3, tol = toluene), a new synthesis of the 1,3‐diphosphete complexes [Cp″′Co(η4‐P2C2tBu2)] (1a) and [Cp″′Co(η4‐P2C2iPr2)] (1b) was found, and their reactions with the Lewis acids W(CO)4 and CuI halides were investigated. The reaction of 1b with W(CO)4(nbd) (nbd = norbornadiene) leads to the complex [(Cp″′Co)(μ,η4:1‐{PCiPr}2)]2W(CO)4 (2) with the two diphosphete complexes 1b coordinated trans to a central W(CO)4 moiety. The reactions of 1a with CuI halides result in different products depending on the stoichiometry. In a 1:1 ratio, the dimeric compounds 3a–c [(Cp″′Co)(μ,η4:1‐{PCtBu}2)Cu(μ‐X)]2 (3a: X = Cl; 3b: X = Br, 3c: X = I) were isolated, whereas an excess of CuX gave the two‐dimensional polymers [({Cp″′Co}{μ3,η4:1:1‐(PCtBu)2})2(Cu{μ3‐X})4]n (6a: X = Cl, 6b: X = Br, 6c: X = I). From the reaction of 1a and 1b with CuBr and CuI in a 1:2 or 2:3 ratio, the one‐dimensional polymers [({Cp″′Co}{μ3,η4:1:1‐(PCR)2})({Cp″′Co}{μ,η4:1‐(PCR)2})(Cu{μ3‐X})4]n (4a: X = Br, R = iPr, 4b: X = I, R = iPr, 4c: X = I, R = tBu) are formed. From the reaction of 1a with CuI, a second product, [({Cp″′Co}{μ3,η4:1:1‐(PCtBu)2})(Cu{μ3‐I})4(MeCN)2]n (5), was isolated by using CH3CN for crystallization. The products were comprehensively characterized by spectroscopic methods, X‐ray crystallography, and 31P magic angle spinning (MAS) NMR spectroscopy.
Improved Yields for the Palladium‐Mediated 11C‐Carbonylation Reaction Using Microwave Technology
Authors: Dahl Kenneth , Schou Magnus , Rahman Obaidur , Halldin Christer 
Published: November 2013

AbstractMicrowave heating technology was applied for the palladium‐mediated 11C‐carbonylation of aryl halides and triflates at ambient pressure using xantphos as supporting ligand. Improved yields were observed for the 11C‐aminocarbonylation of electron‐deficient aryl halides in comparison to thermal heating and the approach even allowed the use of an aryl chloride as substrate. The scope of this reaction was further extended to 11C‐labeled aryl acid and two 11C‐labeled aryl esters.
Investigations on the Operation of Stereochemical Drift in the Wittig Reaction by NMR and Variable‐Temperature NMR Spectroscopy of Oxaphosphetane Intermediates and Their Quench Products
Authors: Byrne Peter A. , Muldoon Jimmy , Ortin Yannick , Müller‐Bunz Helge , Gilheany Declan G. 
Published: November 2013

AbstractWithin the currently accepted mechanism of the Li‐salt‐free Wittig reaction, the phenomenon of stereochemical drift remains the one remaining “loose end” in an otherwise internally consistent explanation of a large body of diverse observations. The term describes the nonstereospecific decomposition of the oxaphosphetane (OPA) intermediate in reactions of certain alkylides with certain aldehydes. In this paper, it is shown that the previous examples in which drift occurs are not merely isolated aberrations from the observed norm, but rather that there is a general phenomenon in reactions of ethylides with benzaldehydes. Variable‐temperature NMR (VTNMR) spectroscopy was used to establish that the amount and diastereomeric ratio of the OPA intermediates do not change below a certain temperature. At and above the temperature at which OPA decomposition to alkene and phosphine oxide begins to occur, the alkene shows a different diastereomeric ratio to the OPA, which indicates the occurrence of stereochemical drift. In one example, owing to an apparent remarkable coincidence of rates, the diastereomeric ratio of the OPA does not change above the decomposition temperature, even though stereochemical drift occurs in the formation of the alkene product. An alternative mechanism for drift involving its catalysis by aldehyde was not confirmed. Drift was also shown not to occur in similar Wittig reactions of structurally related longer‐chain alkylides by stereospecific decomposition of OPA intermediates generated from β‐hydroxyphosphonium salts (β‐HPSs). The extremely useful (and generally applicable) NMR techniques, 1H–31P HMBC and selective 1H{31P}, which we have utilised to establish kinetic diastereomeric ratios, are described in full for the first time. Details of the determination of the relative stereochemistry of two β‐HPSs (derived from acid quenching of OPAs) by X‐ray crystallography are also given.
Enantioselective Organocatalytic Synthesis of α‐Cyclopropylphosphonates through a Domino Michael Addition/Intramolecular Alkylation Reaction
Authors: Faísca Phillips Ana Maria , Barros Maria Teresa 
Published: November 2013

AbstractAn organocatalytic domino reaction consisting of Michael addition/intramolecular alkylation between α,β‐unsaturated aldehydes and bromophosphonoacetates was developed. Highly functionalised cyclopropylphosphonates containing three chiral centres, one of them quaternary, were obtained with good diastereoselectivities of up to 83:17 and very high enantioselectivities of up to 99 %.
Silver(I)‐Mediated Dual Cleavage of C–C and C–O Bonds in the Reaction of Diarylmethylenecyclopropanes with Tetrahydrofuran: Synthesis of 4‐(3‐Halobut‐3‐enyloxy)butyl 2,2,2‐Trifluoroacetate Derivatives
Authors: Chen Gen‐Qiang , Tang Xiang‐Ying , Shi Min 
Published: November 2013

AbstractThe reaction of methylenecyclopropanes (MCPs) with tetrahydrofuran (THF) proceed smoothly in the presence of AgOC(O)CF3 and electrophilic halogenation reagents to give the corresponding 4‐(3‐halobut‐3‐enyloxy)butyl 2,2,2‐trifluoroacetate derivatives in moderate yields through dual cleavage of C–C and C–O bonds under mild conditions.
A Convenient Route for the Synthesis of 3‐Deazaspongosine
Authors: Bande Omprakash , Herdewijn Piet 
Published: November 2013

AbstractThe first chemical synthesis of the 3‐deazaspongosine nucleoside is described, starting from commercially available 4‐amino‐2,6‐dichloropyridine. The key step is the introduction of required functional groups at the 2 and 6 positions of the 4‐amino‐3‐nitropyridine without any conflict in the synthesis of nucleobase. Regioselective nucleophilic substitution with allyl alkoxide at the 2 position of 4‐amino‐2,6‐dimethoxypyridine, followed by sequential deallylation and chlorination led to the desired 2‐chloro derivative. Ring closure of the 3,4‐diaminopyridine and stereoselective glycosylation of the imidazo[4,5‐c]pyridine with tetraacetate‐protected ribofuranose gave only the N9‐β‐isomer. A final nucleophilic displacement of the 6‐chloride by hydrazine followed by reduction with Raney Nickel gave the desired 3‐deazaspongosine.
Synthesis of GABOB and GABOB‐Based Chiral Units Possessing Distinct Protecting Groups
Authors: Ivšić Trpimir , Dokli Irena , Rimac Ana , Hameršak Zdenko 
Published: November 2013

AbstractIn addition to the varied biological activity of GABOB (4‐amino‐3‐hydroxybutanoic acid), the structure of its protected derivatives makes them interesting chiral intermediates for the synthesis of more complex compounds. A stereoselective route to GABOB derivatives with three different protecting groups is presented, using anhydride desymmetrization as a chirality‐inducing step. Selective removal of the protecting groups gave compounds with a free carboxylic acid or hydroxy group. Removal of all of the protecting groups allowed GABOB to be isolated in good yield and with excellent ee.
Fused Azacalix[4]arenes
Authors: Haddoub Rose , Touil Mounia , Chen Zhongrui , Raimundo Jean‐Manuel , Marsal Philippe , Elhabiri Mourad , Siri Olivier 
Published: November 2013

AbstractThe synthesis of unprecedented fused azacalixarenes (dimers and trimer) through successive nucleophilic aromatic substitutions is described. Absorption spectrophotometric and theoretical studies demonstrated that these oligomers share common phenyl moieties that enable conjugation of the whole π‐system and a multiconcave geometry with aligned cavities because of the high flexibility of these macrocycles.
Lab‐on‐a‐Chip Sensor with Evaporated Bismuth Film Electrode for Anodic Stripping Voltammetry of Zinc
Authors: Kang Wenjing , Pei Xing , Yue Wei , Bange Adam , Heineman William R. , Papautsky Ian 
Published: November 2013

AbstractIn this work, we report on the development of a lab‐on‐a‐chip electrochemical sensor that uses an evaporated bismuth electrode to detect zinc using square wave anodic stripping voltammetry. The microscale electrochemical cell consists of a bismuth working electrode, an integrated silver/silver chloride reference electrode, and a gold auxiliary electrode. The sensor exhibits a linear response in 0.1 M acetate buffer at pH 6 with zinc concentrations in the 1–30 μM range and a calculated detection limit of 60 nM. The sensor successfully detected zinc in a bovine serum extract and the results were corfirmed by independent AAS measurements. Our results demonstrate the advantageous qualities of this lab‐on‐a‐chip electrochemical sensor for clinical applications, which include small sample volume (µL scale), reduced cost, short response time and high accuracy at low concentrations of analyte.
Voltammetry of Immobilized Particles of Cannabinoids
Authors: Novak Ivana , Mlakar Marina , Komorsky‐Lovrić Šebojka 
Published: November 2013

AbstractA new electrochemical method for the detection of cannabinoids in food products is proposed. The method is based on the voltammetry of microparticles at a paraffin‐impregnated graphite electrode. In square‐wave voltammetry, in 0.1 M KNO3 at pH 7, the responses of delta‐9‐tetrahydrocannabinol, cannabinol and cannabidiol consist of a single peak with the maximum at 0.55 V±0.01 V. This peak is ascribed to the electrooxidation of the phenol group to phenoxy radical. In microparticles of hemp and marijuana cannabinoids can be detected in pure drug as well as in the mixture with foreign insoluble powders.
Fe3O4 Microspheres and Graphene Oxide Encapsulated with Chitosan: A New Platform for Sensitive Determination of Hydroquinone and Catechol
Authors: Lai Ting , Cai Weihua , Du Haijun , Ye Jianshan 
Published: November 2013

AbstractA novel sensor for sensitive determination of hydroquinone (HQ) and catechol (CC) was proposed using a Fe3O4 microspheres‐graphene oxide (Fe3O4‐GO) composites modified glassy carbon electrode (GCE) which was further encapsulated with chitosan (Chit‐Fe3O4‐GO/GCE). The excellent electrocatalytic performance is probably related to the strong synergistic effect of the composites. The proposed sensor shows a linear response for HQ and CC in wide concentration ranges from 1.5 to 150 µM and 1 to 410 µM, with detection limits (S/N=3) of 20 and 250 nM, respectively. Additionally, the sensor exhibits good selectivity and stability in tap water samples.
Pilot spark energy in the cone calorimeter: a source of measurement uncertainties
Authors: Ochoterena Raúl , Försth Michael 
Published: November 2013

SUMMARYThis work presents measurements meant to study the influence of the spark energy on the time to ignition of a given material in the cone calorimeter. For this purpose, square slabs of particle board were tested under two radiation intensities until ignition occurred using two spark energies for each intensity level. Results show that increasing the spark energy leads to a reduction in the ignition time regardless of the radiation intensity. However, the influence of the spark energy on the time to ignition is, in absolute numbers, larger for the low radiation intensity case than for the high radiation intensity case. Nonetheless, the proportional difference is nearly 10% for both levels of heat radiation. Results from this work confirm that there is an influence of the spark energy on the time to ignition of a given material suggesting that a narrower and more specific definition of the ignition circuits allowed in the cone calorimeter would be highly beneficial for ensuring repeatable results among laboratories. Copyright © 2013 John Wiley & Sons, Ltd.
Genetic Prediction of Quantitative Lipid Traits: Comparing Shrinkage Models to Gene Scores
Authors: Warren Helen , Casas Juan‐Pablo , Hingorani Aroon , Dudbridge Frank , Whittaker John 
Published: November 2013

ABSTRACTAccurate genetic prediction of quantitative traits related to complex disease risk would have potential clinical impact, so investigation of statistical methodology to improve predictive performance is important. We compare a simple approach of polygenic scores using top ranking single nucleotide polymorphisms (SNPs) to a set of shrinkage models, namely Ridge Regression, Lasso and Hyper‐Lasso. These penalised regression methods analyse all genotyped SNPs simultaneously, potentially including much larger sets of SNPs in the models, not only those with the smallestPvalues. We compare the accuracy of these models for predicting low‐density lipoprotein (LDL) and high‐density lipoprotein (HDL) cholesterol, two lipid traits of clinical relevance, in the Whitehall II and British Women's Health and Heart Study cohorts, using SNPs from the HumanCVD BeadChip. For gene scores, the most accurate predictions arise from multivariate weighted scores and include only a small number of SNPs, identified as top hits by the HumanCVD BeadChip. Furthermore, there was little benefit from including external results from published sets of SNPs. We found that shrinkage approaches rarely improved significantly on gene score results. Genetic predictive performance is trait specific, depending on the heritability and genetic architecture of the trait, and is limited by the training data sample size. Our results for lipid traits suggest no current benefit of more complex methods over existing gene score methods. Instead, the most important choice for the prediction model is the number of SNPs and selection of the most predictive SNPs to include. However further comparisons, in larger samples and for other phenotypes, would still be of interest.
Self‐Optimizing Reactor Systems: Algorithms, On‐line Analytics, Setups, and Strategies for Accelerating Continuous Flow Process Optimization
Authors: Fabry David C. , Sugiono Erli , Rueping Magnus 
Published: November 2013

AbstractThis review provides an overview of recent developments in the area of continuous flow process optimization by employing self‐optimizing reactor systems. Although only few reactor concepts have been realized to date, impressive progress has been made, which now allows fully automated reaction optimization without the need of human interactions.
Ecological momentary assessment for chronic pain in fibromyalgia using a smartphone: A randomized crossover study
Authors: Garcia‐Palacios A. , Herrero R. , Belmonte M.A. , Castilla D. , Guixeres J. , Molinari G. , Baños R.M. , Botella C. 
Published: November 2013

AbstractBackgroundDaily diaries are a useful way of measuring fluctuations in pain‐related symptoms. However, traditional diaries do not assure the gathering of data in real time, not solving the problem of retrospective assessment. Ecological momentary assessment (EMA) by means of electronic diaries helps to improve repeated assessment. However, it is important to test its feasibility in specific populations in order to reach a wider number of people who could benefit from these procedures.MethodsThe present study compares the compliance and acceptability of an electronic diary running on a smartphone using a crossover design for a sample with a specific pain condition, fibromyalgia and low familiarity with technology. Forty‐seven participants were randomly assigned to one of two conditions: (1) paper diary – smartphone diary and (2) smartphone diary – paper diary, using each assessment method for 1 week.ResultsThe findings of this study showed that the smartphone diary made it possible to gather more accurate and complete ratings. Besides, this method was well accepted by a sample of patients with fibromyalgia referred by a public hospital, with an important proportion of participants with low level of education and low familiarity with technology.ConclusionsThe findings of this study support the use of smartphones for EMA even in specific populations with a specific pain condition, fibromyalgia and with low familiarity with technology. These methods could help clinicians and researchers to gather more accurate ratings of relevant pain‐related variables even in populations with low familiarity with technology.