bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpniktogenkationen: Neue Perspektiven in der Koordinationschemie
Authors: Robertson Alasdair P. M. , Gray Paul A. , Burford Neil 
Published: May 2014

AbstractPniktanderivate können die Rolle von sowohl 2 e−‐Donoren (Lewis‐Basen) als auch 2 e−‐Akzeptoren (Lewis‐Säuren) übernehmen. Als prototypische Liganden in der Koordinationschemie von Übergangsmetallen bilden Amine und Phosphane auch Komplexe mit Lewis‐Säuren des p‐Blocks, die verschiedene Pniktogen‐zentrierte Akzeptoren umfassen. Die Lewis‐Acidität von Pniktogenzentren kann durch eine kationische Ladung verstärkt werden, was in den letzten Jahren zur Entwicklung von Verbindungen mit koordinativen Pn‐Pn‐ und Pn‐Pn′‐Wechselwirkungen genutzt wurde. Diese Verbindungen bieten die außergewöhnliche Möglichkeit zur homoatomaren Koordinationsbindung und ermöglichen die Entwicklung von Komplexen mit einem freien Elektronenpaar am Akzeptorzentrum. Dieser Aufsatz weist neue Richtungen für die systematische Erweiterung der Koordinationschemie von der Übergangsreihe zum p‐Block.
Simple but Precise Engineering of Functional Nanocapsules through Nanoprecipitation
Authors: Yan Xibo , Delgado Marco , Fu Amy , Alcouffe Pierre , Gouin Sébastien G. , Fleury Etienne , Katz Joseph L. , Ganachaud François , Bernard Julien 
Published: May 2014

AbstractA general, rapid, and undemanding method to generate at will functional oil‐filled nanocapsules through nanoprecipitation is reported. On the basis of polymer and hexadecane/water/acetone phase diagrams, the composition can be set so that polymer chains preferentially stick at the interface of the oil droplets to create nanocapsules. The nanocapsules can be decorated with biorelevant molecules (biotin, fluorescent tags, metal nanoparticles) within the shell and loaded with hydrophobic molecules in a simple one‐pot procedure.
Direct Asymmetric Dearomatization of Pyridines and Pyrazines by Iridium‐Catalyzed Allylic Amination Reactions
Authors: Yang Ze‐Peng , Wu Qing‐Feng , You Shu‐Li 
Published: May 2014

AbstractThe first iridium‐catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines and pyrazines has been realized. 2,3‐Dihydroindolizine and 6,7‐dihydropyrrolo[1,2‐a]pyrazine derivatives were obtained with excellent yields and enantioselectivity. This methodology features dearomatization by direct N‐allylic alkylation of pyridines or pyrazines under mild reaction conditions.
Electrospinning silica/polyvinylpyrrolidone composite nanofibers
Authors: Newsome Toni E. , Olesik Susan V. 
Published: May 2014

ABSTRACTSmall diameter nanofibers of silica and silica/polymer are produced by electrospinning silica/polyvinylpyrrolidone (SiO2/PVP) mixtures composed of silica nanoparticles dispersed in polyvinylpyrrolidone solutions. By controlling various parameters, 380 ± 100 nm diameter composite nanofibers were obtained with a high silica concentration (57.14%). When the polymer concentration was low, “beads‐on‐a‐string” morphology resulted. Nanofiber morphology was affected by applied voltage and relative humidity. Tip‐to‐collector distance did not affect the nanofiber diameter or morphology, but it did affect the area and thickness of the mat. Heat treatment of the composite nanofibers at 200°C crosslinked the polymer yielding solvent‐resistant composite nanofibers, while heating at 465°C calcined and selectively removed the polymer from the composite. Crosslinking did not change the nanofiber diameter, while calcined nanofibers decreased in diameter (300 ± 90 nm) and increased in surface area to volume ratio. Nanofibers were characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40966.
Surface modification of electrospun chitosan nanofibrous mats for antibacterial activity
Authors: Kangwansupamonkon Wiyong , Tiewtrakoonwat Walaiwan , Supaphol Pitt , Kiatkamjornwong Suda 
Published: May 2014

ABSTRACTChitosan (CS) blended with poly(ethylene oxide) (PEO) was electrospun into nanofibrous mats. The spinning solution of 6.7 : 0.3 (% w/v) of CS : PEO was dissolved in a 70 : 30 (v/v) trifluoroacetic acid/dichloromethane solution. The obtained fibers were smooth without beads on their surfaces and average diameter of the fiber was 272 ± 56 nm. N‐(2‐hydroxyl) propyl‐3‐trimethyl ammonium chitosan chloride (HTACC) and N‐benzyl‐N,N‐dimethyl chitosan iodide (QBzCS) were each prepared from the CS/PEO mats. They were identified by Fourier‐transform infrared and X‐ray photoelectron spectroscopy and degree of swelling in water. Both quaternized electrospun chitosan mats exhibited superior antibacterial activity to the unmodified electrospun CS/PEO against Staphylococcus aureus and Escherichia coli at short contact times. After 4 h of contact, the reduction of both bacterial strains by CS/PEO, HTACC, and QBzCS was equal at about 99–100%. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40981.
Recent advances in development and application of derivatization reagents having a benzofurazan structure: a brief overview
Authors: Santa Tomofumi 
Published: May 2014

ABSTRACTChemical derivatization is often used to improve the separation efficiency and to enhance the detectability of the target compounds in high‐performance liquid chromatography and capillary electrophoresis. The derivatization reagents having a benzofurazan (2,1,3‐benzoxadiazole) structure are one of the most often used reagent for this purpose. In this paper, the recent advances in the development and the application of benzofurazan derivatization reagents are reviewed. Copyright © 2013 John Wiley & Sons, Ltd.
Biological and chemical standardization of a hop (Humulus lupulus) botanical dietary supplement
Authors: Krause Elizabeth , Yuan Yang , Hajirahimkhan Atieh , Dong Huali , Dietz Birgit M. , Nikolic Dejan , Pauli Guido F. , Bolton Judy L. , van Breemen Richard B. 
Published: May 2014

ABSTRACTConcerned about the safety of conventional estrogen replacement therapy, women are using botanical dietary supplements as alternatives for the management of menopausal symptoms such as hot flashes. Before botanical dietary supplements can be evaluated clinically for safety and efficacy, botanically authenticated and standardized forms are required. To address the demand for a standardized, estrogenic botanical dietary supplement, an extract of hops (Humulus lupulus L.) was developed. Although valued in the brewing of beer, hop extracts are used as anxiolytics and hypnotics and have well‐established estrogenic constituents. Starting with a hop cultivar used in the brewing industry, spent hops (the residue remaining after extraction of bitter acids) were formulated into a botanical dietary supplement that was then chemically and biologically standardized. Biological standardization utilized the estrogen‐dependent induction of alkaline phosphatase in the Ishikawa cell line. Chemical standardization was based on the prenylated phenols in hops that included estrogenic 8‐prenylnaringenin, its isomer 6‐prenylnaringenin, and pro‐estrogenic isoxanthohumol and its isomeric chalcone xanthohumol, all of which were measured using high‐performance liquid chromatography–tandem mass spectrometry. The product of this process was a reproducible botanical extract suitable for subsequent investigations of safety and efficacy. Copyright © 2014 John Wiley & Sons, Ltd.
Replacement of missing lateral incisors with lithium disilicate glass‐ceramic veneer‐fixed dental prostheses: a clinical report
Authors: Bissasu Sami M. , Al‐houri Nabil A. 
Published: May 2014

Key Clinical MessageThis report describes the use of lithium disilicate glass‐ceramic veneer‐fixed dental prostheses in replacing congenitally missing maxillary lateral incisors. This kind of prosthesis has an advantage over a lingual‐retainer resin‐bonded fixed dental prosthesis in its capability of changing the color and shape of the abutment teeth. The prostheses provided an acceptable esthetics and comfort for the patient.
Behcet's disease presenting with recurrent ocular, oral, and scrotal inflammatory lesions in a young Tanzanian man: a case report
Authors: Meda John R. , Seni Jeremiah , Mpondo Bonaventura , Peck Robert N. , Jaka Hyasinta , Kilonzo Semvua B. 
Published: May 2014

Key Clinical MessageBehcet's disease (BD) is a rare condition which is diagnosed clinically. Only few cases have been reported in sub‐Saharan Africa. We report a Tanzanian male who presented with typical features of BD and was successfully treated. There should be an increase in awareness on BD to improve the management.
Biomimetic Synthesis of Shaped and Chiral Silica Entities Templated by Organic Objective Materials
Authors: Jin Ren‐Hua , Yao Dong‐Dong , Levi Rumi (Tamoto) 
Published: May 2014

AbstractOrganic molecules with accompanying self‐organization have been a great subject in chemistry, material science and nanotechnology in the past two decades. One of the most important roles of organized organic molecules is the capability of templating complexly structured inorganic materials. The focus of this Minireview is on nanostructured silica with divergent morphologies and/or integrated chirality directed by organic templates of self‐assembled polyamine/polypeptides/block copolymers, chiral organogels, self‐organized chiral amphiphiles and chiral crystalline complexes, etc., by biomimetic silicification and conventional sol–gel reaction. Among them, biosilica (diatoms and sponges)‐inspired biomimetic silicifications are particularly highlighted.
General Catalytic Methylation of Amines with Formic Acid under Mild Reaction Conditions
Authors: Sorribes Iván , Junge Kathrin , Beller Matthias 
Published: May 2014

AbstractA general catalytic protocol for the methylation of amines has been developed applying, for the first time, formic acid as the C1 building block and silanes as reducing agents. A broad range of aromatic and aliphatic, both primary and secondary, amines has been converted to the corresponding tertiary amines including [N‐13C]‐labelled drugs in good to excellent yields under mild conditions.
Two‐step Synthesis of Multi‐Substituted Amines by Using an N‐Methoxy Group as a Reactivity Control Element
Authors: Yoritate Makoto , Meguro Tatsuhiko , Matsuo Naoya , Shirokane Kenji , Sato Takaaki , Chida Noritaka 
Published: May 2014

AbstractThe development of a two‐step synthesis of multi‐substituted N‐methoxyamines from N‐methoxyamides is reported. Utilization of the N‐methoxy group as a reactivity control element was the key to success in this two‐step synthesis. The first reaction involves a N‐methoxyamide/aldehyde coupling reaction. Whereas ordinary amides cannot condense with aldehydes intermolecularly due to the poor nucleophilicity of the amide nitrogen, the N‐methoxy group enhances the nucleophilicity of the nitrogen, enabling the direct coupling reaction. The second reaction in the two‐step process was nucleophilic addition to the N‐methoxyamides. Incorporation of the N‐methoxy group into the amides increased the electrophilicity of the amide carbonyls and promoted the chelation effect. This nucleophilic addition enabled quick diversification of the products derived from the first step. The developed strategy was applicable to a variety of substrates, resulting in the elaboration of multi‐substituted piperidines and acyclic amines, as well as a substructure of a complex natural alkaloid.
Thermodynamic Impact of Abasic Sites on Simulated Translesion DNA Synthesis
Authors: Malina Jaroslav , Brabec Viktor 
Published: May 2014

AbstractLoss of a base in DNA and the creation of an abasic (apurinic/apyrimidinic, AP) site is a frequent lesion that may occur spontaneously, or as a consequence of the action of DNA‐damaging agents. The AP lesion is mutagenic or lethal if not repaired. We report a systematic thermodynamic investigation by differential scanning calorimetry on the evolution, during primer extension, of a model AP site in chemically simulated DNA translesion synthesis. Incorporation of dAMP (deoxyadenosine monophosphate), as well as dTMP (deoxythymidine monophosphate), opposite an AP site is enthalpically unfavorable, although incorporation of dTMP is more enthalpically unfavorable than that of dAMP. This finding is in a good agreement with experimental data showing that AP sites block various DNA polymerases of eukaryotic and prokaryotic origin and that, if bypassed, dAMP is preferentially inserted, whereas insertion of dTMP is less likely. The results emphasize the importance of thermodynamic contributions to the insertion of nucleotides opposite an AP site by DNA polymerases.
The value of second opinion in thyroid cytology: A review
Authors: Gerhard Rene , Boerner Scott L. 
Published: May 2014

BACKGROUNDSecond‐opinion diagnosis (SOD) on pathological material is an accepted practice before definitive therapy is considered for referred patients. The thyroid gland is an anatomical site prone to diagnostic disagreement between pathologists. We performed a review of the literature that addressed the role of interinstitutional SOD on thyroid fine‐needle aspirations (FNAs).METHODSNine studies comprising second opinions on thyroid FNAs were selected. The parameters analyzed included: discordances between the initial diagnoses (IDs) and SODs; cytohistologic correlation; changes in the clinical management of the patients with thyroid nodules after SOD. The same parameters were applied to the “indeterminate” diagnostic category comprising cases initially reported as “atypia,” “atypia of undetermined significance/follicular lesion of undetermined significance,” “suspicious for a follicular neoplasm,” “follicular neoplasm,” “suspicious,” and “suspicious for malignancy.”RESULTSA total of 7154 thyroid FNAs were retrieved, showing an overall discordance rate between ID and SOD of 28.6%. In general, SOD was better supported by clinical follow‐up and histological diagnosis, showing higher diagnostic accuracy in comparison with ID. Almost one‐third (30.4%) of the discordant cases resulted in changes in the clinical management of patients with thyroid nodules. Numerous thyroid FNAs initially categorized as “indeterminate” were definitively classified as benign or malignant by SOD, with an overall diagnostic resolution rate of 42.5%, sensitivity of 97.9%, and diagnostic accuracy of 73.7%.CONCLUSIONSSecond‐opinion review of thyroid FNA improves diagnostic accuracy and potentially changes clinical management. SOD also demonstrates a significative rate of diagnostic resolution for thyroid FNAs originally diagnosed as “indeterminate.” Cancer (Cancer Cytopathol) 2014;122:611–619. © 2014 American Cancer Society.
Selective Binding of Amino Acids on Europium‐Substituted Polyoxometalates and the Interaction‐Induced Luminescent Enhancement Effect
Authors: Li Hong‐Wei , Wang Yizhan , Zhang Teng , Wu Yuqing , Wu Lixin 
Published: May 2014

AbstractA europium‐substituted polyoxometalate (K13[Eu(SiW10MoO39)2]⋅28 H2O, EuSiWMo) can selectively bind to basic amino acids, namely, lysine, arginine, and histidine, and induce the emission enhancement of Eu3+ significantly. The mechanism is attributed to electrostatic interactions and hydrogen bonds between basic residues of the amino acids and negative charges of EuSiWMo based on the 1H NMR titration spectra of amino acids and time‐resolved fluorescence decay curves of EuSiWMo.
Towards deconfounding hydrological and seasonal temperature variability in the determination of selected limnological variables of a temperate floodplain ecosystem
Authors: Palijan Goran 
Published: May 2014

AbstractThis paper presents a methodological approach that can aid the assessment of variation in limnological variables in response to hydrological phases and seasonal temperature variation. The investigation was conducted in the Danube River floodplain, Kopački Rit, Croatia. The proposed approach facilitates a more accurate examination of the effects of first factor, while maintaining second factor less variable, and vice versa. Samples were collected in the floodplain channel and lake along a temporal connectivity gradient, and were grouped according to three hydrological phases (isolation, flow pulse and flood pulse) and according to three seasons (spring, summer and autumn). A permutational multivariate analysis of variance was used to analyse the hydrological effects within seasons, as well as seasonal effects within hydrological phases on selected limnological variables: pH, conductivity, dissolved oxygen, nitrites, nitrates, ammonium, total Kjeldahl nitrogen, total phosphorus, chlorophyll a concentrations and ratio of copiotrophic to oligotrophic bacteria. A multivariate data cloud was structured by hydrological phases during all investigated seasons, but not by all seasons during different hydrological phases. The strongest impact of hydrological phases on limnological variables occurred during summer. Seasonal effects were significant during the isolation and the flood pulse phases. The flow pulse phase somehow obscured the effects of seasonal change, resulting in temporal floodplain homogenization. One possible explanation is that water temperature determines potential limnological conditions, whereas hydrology determines actual conditions. Such results must be taken into account if the accurate effects of hydrology and seasonal change are to be assessed in temperate floodplain ecosystems. Copyright © 2014 John Wiley & Sons, Ltd.
(Benzimidazolylmethyl)amine ZnII and CuII Carboxylate Complexes: Structural, Mechanistic and Kinetic Studies of Polymerisation Reactions of ϵ‐Caprolactone
Authors: Attandoh Nelson W. , Ojwach Stephen O. , Munro Orde Q. 
Published: May 2014

AbstractCompounds N‐(1H‐benzimidazol‐2‐ylmethyl)aniline (L1), N‐(1H‐benzimidazol‐2‐ylmethyl)‐2‐bromoaniline (L2), and N‐(1H‐benzimidazol‐2‐ylmethyl)‐2‐aminothiophenol (L3) react with ZnII and CuII carboxylates to form complexes [Zn2(L1)2(OBn)4] (1), [Zn2(L2)2(OBn)4] (2), [Zn2(L3)2(OBn)4] (3), [Cu2(L2)2(OBn)4] (4), [Zn(L1)2(OAc)2] (5), [Zn(L2)2(OAc)2] (6) and [Cu2(L1)2(OAc)4] (7). Structures of 2, 4 and 6 revealed that L1–L3 are monodentate, binding through the imidazolyl N‐atom. The X‐band EPR spectrum of 4 in the solid state is consistent with an antiferromagnetically‐coupled (singlet) ground state and a low‐lying EPR‐active triplet excited state characterised by two main transitions. In dimethyl sulfoxide (DMSO) solution, a single resonance confirmed the retention of the dinuclear paddlewheel core. Complexes 1–7 formed active catalysts towards ring‐opening polymerisation of ϵ‐caprolactone. The polymerisation reactions follow first‐order kinetics with respect to the monomer and occur through a coordination–insertion pathway.
Luminescent Polymer Films from Simple Processing of Coronene and Europium Precursors in Water
Authors: Planells Miquel , Klampaftis Efthymios , Congiu Martina , Shivanna Ravichandran , Rao K. Venkata , Chepelin Oleg , Jones Anita C. , Richards Bryce S. , George Subi J , Narayan K. S. , Robertson Neil 
Published: May 2014

AbstractWe describe the preparation and optical characterisation of a coronene tetracarboxylate salt (CS) in polyvinyl alcohol (PVA) thin film solutions processed from water, neat or mixed with varying ratios of a europium tris(hexafluoroacetylacetoanto) diaquo complex [Eu(hfac)3(H2O)2]. Neat CS‐PVA showed not only well‐defined fluorescence peaks but also a long‐lived phosphorescence emission, persisting for more than 1 second. Interaction between the CS and EuIII molecules, mediated by means of carboxylate coordination to the EuIII, was attained by simple incorporation into the PVA polymer matrix and resulted in energy transfer from the coronone antenna to the europium centre. Under various blend ratios of CS and the EuIII complex, total photoluminescence quantum yields of typically around 30 % were achieved. The straightforward processing of this type of self‐assembled chromophore‐lanthanide system into a luminescent polymer film offers potential for application to other chromophores, lanthanides and polymers.
Lipopeptide‐modified PEG‐PE‐based pharmaceutical nanocarriers for enhanced uptake in blood–brain barrier cells and improved cytotoxicity against glioma cells
Authors: Sydow Karl , Torchilin Vladimir P. , Dathe Margitta 
Published: May 2014

Surface modification of nanoparticles is a promising approach for enhancing the delivery of drugs into the brain and cancer cells. Recently cationic lipopeptide micelles showed selective uptake into endothelial cells of brain microvessels. Here, we show that lipopeptides are promising tools to deliver an anticancer drug incorporated into PEGylated lipid (PEG‐PE) micelles to brain endothelial cells and into glioblastoma cells. PEG‐PE micelles containing PCL were stably modified with different arginine (R‐) and lysine (K)‐rich lipopeptides. The size and surface charge of the micelles did not change after modification with lipopeptides. Flow cytometry (FACS) and confocal laser scanning microscopy (CLSM) revealed pronounced interaction of lipopeptide‐modified micelles with brain endothelial cells. Furthermore, the co‐localisation of both the fluorescent lipopeptides and a marker lipid of micelles within human glioblastoma cells (U87MG) confirmed the integrity of the carrier after internalisation. FACS studies showed that the arginine‐rich lipopeptide caused most efficient uptake into the cancer cells. The pronounced uptake correlated with higher a cytotoxic effect of PCL incorporated into peptide‐tagged micelles compared to the unmodified carriers. As a conclusion, arginine‐rich lipopeptides known to enhance the uptake of different NP into blood–brain barrier endothelial cells seem to be also encouraging candidates for targeting brain‐located tumors.Practical applications: The surface modification of existing carrier systems with lipopeptides to improve their applicability has been proven by this work. Furthermore, the findings in this study are the basis for further improvement of lipopeptide modified PEG‐PE micelles and their possible in vivo application in animal models of glioblastoma. The incorporation of anti‐cancer drugs as well as diagnostic agents and their delivery to and beyond the BBB can be a tool for a broad number of further investigations.Lipopeptide (P2Rn)‐modified PEG‐PE micelles show enhanced uptake into human glioma cells (nuclei stained cyan). This improved uptake correlates with higher cytotoxicity of incorporated anti‐cancer drug paclitaxel (PCL).
Implications of the spandrel type on the lateral behavior of unreinforced masonry walls
Authors: Parisi Fulvio , Augenti Nicola , Prota Andrea 
Published: May 2014

SUMMARYSeismic response of unreinforced masonry (URM) buildings is largely influenced by nonlinear behavior of spandrels, which provide coupling between piers under in‐plane lateral actions. Seismic codes do not appropriately address modeling and strength verification of spandrels, adapting procedures originally proposed for piers. Therefore, research on spandrels has received significant attention in some earthquake‐prone countries, such as Italy and New Zealand. In the last years, the authors of this paper have performed both monotonic and cyclic in‐plane lateral loading tests on full‐scale masonry walls with single opening and different spandrel types. Those tests were carried out in a static fashion and with displacement control. In this paper, experimental outcomes for two as‐built specimens are presented and compared with those obtained in the past for another as‐built specimen with a wooden lintel above the opening. In both newly tested specimens, the masonry above the opening was supported by a shallow masonry arch. In one of those specimens, a reinforced concrete (RC) bond beam was realized on top of the spandrel, resulting in a composite URM‐RC spandrel. Then, the influence of spandrel type is analyzed in terms of observed damage, force–drift curves, and their bilinear idealizations, which allowed to compare displacement ductility and overstrength of wall specimens. Furthermore, effects of rocking behavior of piers are identified, highlighting their relationship with hysteretic damping and residual drifts. Copyright © 2014 John Wiley & Sons, Ltd.