bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses of Spiro[cyclopent[3]ene‐1,3′‐indole]s and Tetrahydrocyclohepta[b]indoles from 2,3‐Disubstituted Indoles through Sigmatropic Rearrangement
Authors: Chakraborty Amrita , Goswami Koushik , Adiyala Akhila , Sinha Surajit 
Published: October 2013

AbstractA NaOH‐mediated protocol was developed for the syntheses of a series of 2′‐arylspiro[cyclopent[3]ene‐1,3′‐indole]s and 6‐alkyl‐5,6,7,10‐tetrahydrocyclohepta[b]indoles in good yields by cyclization through a sigmatropic rearrangement of suitable 2,3‐disubstituted indoles. These precursors that contain a 4‐chloro‐2‐butenyl side chain at the 3‐position were obtained as a mixture of (E) and (Z) isomers through the reactions of o‐alkynylanilines and 3,4‐dichloro‐1‐butene. The cyclization strategy is general, and both medicinally important scaffolds were achieved by changing the substituent at the 2‐position of methyl 3‐(4‐chlorobut‐2‐enyl)‐1H‐indole‐1‐carboxylate. The reaction likely proceeds through [1,3]‐ and [3,3]‐sigmatropic rearrangements of the vinylcyclopropane substituent of the indole intermediate.
An Approach to 2,4‐Substituted Pyrazolo[1,5‐a]pyridines and Pyrazolo[1,5‐a]azepines by Ring‐Closing Metathesis
Authors: Fustero Santos , Román Raquel , Asensio Amparo , Maestro Miguel A. , Aceña José L. , Simón‐Fuentes Antonio 
Published: October 2013

AbstractThe ring‐closing metathesis (RCM) reactions of dienylpyrazoles have been employed in the synthesis of pyrazolo[1,5‐a]pyridine and pyrazolo[1,5‐a]azepine derivatives. Based on this approach, the diastereoselective synthesis of potential peptidomimetics containing four amino acid residues with the second (i+1) and third (i+2) fragments having been substituted by bicyclic frameworks is described.
Electrochemical Determination of the Herbicide Bentazone Using a Carbon Nanotube β‐Cyclodextrin Modified Electrode
Authors: Rahemi V. , Garrido J. M. P. J. , Borges F. , Brett C. M. A. , Garrido E. M. P. J. 
Published: October 2013

AbstractAn electrochemical sensor has been developed for the determination of the herbicide bentazone, based on a GC electrode modified by a combination of multiwalled carbon nanotubes (MWCNT) with β‐cyclodextrin (β‐CD) incorporated in a polyaniline film. The results indicate that the β‐CD/MWCNT modified GC electrode exhibits efficient electrocatalytic oxidation of bentazone with high sensitivity and stability. A cyclic voltammetric method to determine bentazone in phosphate buffer solution at pH 6.0, was developed, without any previous extraction, clean‐up, or derivatization steps, in the range of 10–80 µmol L−1, with a detection limit of 1.6 µmol L−1 in water. The results were compared with those obtained by an established HPLC technique. No statistically significant differences being found between both methods.
Poly(allylamine hydrochloride) Functionalized Multiwalled Carbon Nanotube Modified Carbon Paste Electrode as Acetylcholinesterase Biosensor Transducer
Authors: Çevik Serdar , Timur Suna , Anik Ülkü 
Published: October 2013

AbstractIn this work, a sensitive, practical and reliable acetylthiocholine (ATCh) biosensor based on poly(allylamine hydrochloride) functionalized multiwalled carbon nanotube (PAH/MWCNT) was fabricated and used for pesticide detection. As far as we know, this is the first work that constitutes the usage of PAH and MWCNT for ATCh biosensor. The developed system was characterized by using scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The influence of parameters such as enzyme amount and pH were examined and a linearity between 5×10−5 M−2.0×10−3 M for ATCh was obtained. The proposed biosensor was applied for a model pesticide, monocrotophos, detection. The analytical curve showed an excellent linearity in the monocrotophos concentration range of 1–25 pg/mL with an incubation time of 5 min. Limit of detection and limit of quantification values were calculated as 0.88 and 2.9 pg/mL, respectively. The system was also applied for detection of monocrotophos in grape, tomatoe, tap and mineralized water samples and promising recovery values were obtained.
Influence of Gold Nanoparticle Film Porosity on the Chemiresistive Sensing Performance
Authors: Chow Edith , Raguse Burkhard , Müller Karl‐H. , Wieczorek Lech , Bendavid Avi , Cooper James S. , Hubble Lee J. , Webster Melissa S. 
Published: October 2013

AbstractThe porosity of 1‐hexanethiol‐functionalised gold nanoparticle films was assessed and utilised as chemiresistor sensors. Electrochemical capacitance measurements showed that the accessibility of electrolytes of different ionic strengths into the pores depended on the thickness of the electric double layer formed. A large variation in capacitance was measured in 0.01–1000 mM NaClO4, implying a wide pore size distribution. The change in morphology of the nanoparticle films upon storage in air, water and ethanol for two weeks was investigated. There was a significant decrease in the electrochemical capacitance at high electrolyte concentrations for the ethanol‐stored films compared to the freshly‐prepared films suggesting a decrease in the number of small pores of radii in the range of 0.3–3 nm. This was further supported by optical topographical measurements where a decrease in the thickness of ethanol‐stored films was observed relative to the freshly‐prepared films. The porous nature of the nanoparticle films was found to have an effect on the chemical sensing behaviour. When used as chemiresistor sensors, for the detection of heptane in water, the ethanol‐stored films provided larger resistance changes and longer response times. This suggests that the more densely packed ethanol‐stored films provided more sites that enabled film swelling, and that diffusion of the analyte occurred through the narrower water‐filled pores. This demonstrates the effect of different storage conditions on film morphology and subsequently sensor response.
Mild Hydrothermal Degradation of Cotton Cellulose by using a Mixed‐Metal‐Oxide ZnO–ZrO2 Catalyst
Authors: Yang Fang , Li Gang , Gao Peng , Lv Xiao‐Na , Sun Xiaofeng , Liu Zhi‐Hua , Fan Hongxian 
Published: October 2013

AbstractThis paper presents a process for the degradation of cotton cellulose in the presence of a mixed‐metal‐oxide ZnO–ZrO2 catalyst under mild hydrothermal conditions (463 K, 1.4 MPa). The main products include glucose, fructose, furfural, 5‐hydroxymethylfurfural (HMF), and water‐soluble oligosaccharides. The highest yield of HMF was 10.05 % at 473 K and the conversion ratio of cotton cellulose reached 81 % at 483 K. The desorption peak in ammonia‐temperature programmed desorption (NH3‐TPD) performed on the ZnO–ZrO2 catalyst was near the 463–473 K range for the degradation of cotton cellulose. The tetragonal phase structure of the ZnO–ZrO2 catalyst played an important role in lowering the temperature and pressure for the hydrothermal degradation of cotton cellulose.
Optimization of the process parameters for the removal of reactive yellow dye by the low cost Setaria verticillata carbon using response surface methodology: Thermodynamic, kinetic, and equilibrium studies
Authors: Vidhyadevi T. , Murugesan A. , Kalaivani S.S. , Anil Kumar M. , Thiruvenkada Ravi K.V. , Ravikumar L. , Anuradha C.D. , Sivanesan S. 
Published: October 2013

AbstractA low cost adsorbent prepared from material of biological origin Setaria verticillata (Grasses) has been utilized as an adsorbent for the removal of Reactive Yellow 15 (RY15) dye from an aqueous solution. The combined effect of the initial pH, adsorbent dose, and initial dye concentration was investigated using Response Surface Methodology (RSM). The most influential adsorption factor on each adsorption experimental design response was identified from the Analysis Of Variance (ANOVA). The experimental values of percentage removal were found to be in good agreement with the predicted values. pH value of 2, initial RY15 concentration of 50 mg L−1 and adsorbent dose of 50 mg are found to be the optimum conditions, for adsorption of RY15 from an aqueous solution. Thermodynamic parameters such as change in standard free energy change, enthalpy and entropy ΔGo, ΔHo, and ΔSo have been evaluated, and it has been found that the adsorption process is feasible, exothermic and spontaneous in nature. The experimental data were analyzed by the Langmuir, Freundlich, Sips and Temkin adsorption isotherms. Maximum monolayer adsorption capacity of the RY15 dye is found to be 138.6 mg g−1. The experimental data fitted well with the pseudo‐second order kinetic model. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 855–865, 2014
Special measures in soft ground – a particular area of conflict in tunnelling contracts / Sondermaßnahmen im Lockergestein – ein besonderes bauvertragliches Spannungsfeld
Authors: Gamsjäger Hannes , Satina Jozef 
Published: October 2013

AbstractSpecial situations can pose an extraordinary degree of difficulty and risk levels when tunnelling in soft ground, formations with soft ground character or at transitions to soft ground, especially when combined with low overburden, urban constraints or fault zones. Dealing with such situations is therefore of vital importance, to identify the situation correctly already during site investigation and design phase in order to derive the appropriate technical measures or approach. In addition, these situations are a particular area of conflict in tunnelling contracts when changes in ground conditions with high risk levels are encountered during execution of the works. The paper deals with circumstances and constraints of high risk situations in connection with soft ground tunnelling according to experience. It tries to identify and explain causal chains and interactions for such situations.Sondersituationen beim Tunnelvortrieb im Lockergestein bzw. in Formationen mit Lockergesteinscharakter oder Übergängen von Festgestein zu Lockergestein können außerordentliche Schwierigkeitsgrade und Risiken aufweisen, speziell in Bereichen, wo zudem geringe Überlagerung samt Bebauung oder Störungen im Baugrund vorhanden sind. Der Umgang mit derartigen Situationen ist neben den technischen Herausforderungen – nämlich unter anderem bereits bei der Planung die Situation richtig einzuschätzen bzw. überhaupt zu erkennen und dann noch die richtigen Maßnahmen abzuleiten – auch ein besonderes bauvertragliches Spannungsfeld hinsichtlich adäquater Vertragsgestaltung, einschließlich dem Umgang mit geänderten Baugrundbedingungen und Risikolevels bei der Ausführung. Der folgende Artikel erörtert die Umstände und Zwänge von Hochrisikosituationen im Zusammenhang mit Lockergesteinsvortrieben nach gemachten praktischen Erfahrungen. Es wird dabei versucht die Ursachen und Verkettungen zu identifizieren und zu beleuchten.
Kaunertal power station – the new shafts in the fall to the powerhouse / Kraftwerk Kaunertal – die Schächte des neuen Kraftabstiegs
Authors: Pircher Johannes , Pacher Wolfgang , Neugschwandtner Erich 
Published: October 2013

AbstractThe Tiwag – Tiroler Wasserkraft AG – is replacing the entire fall to the powerhouse at the Kaunertal power station, which has been in operation for about 50 years, in 2012 to 2015. The new facilities are being constructed entirely underground in unusually difficult geology for high‐pressure systems. Works to construct the 4,000 m of tunnels and shafts started in March 2012 and were completed by the middle of June 2013. Part of the construction work is based on the proven NATM and part is based on the modern technology of mechanised tunnelling. After the completion of the caverns, the core of the new system, the 1,430 m long penstock, will be lined with thick‐walled steel armouring and backfilled with concrete.Die Tiwag – Tiroler Wasserkraft AG errichtet in den Jahren 2012 bis 2015 einen neuen Kraftabstieg für das seit rund 50 Jahren in Betrieb befindliche Kaunertalkraftwerk. Die Anlagenteile des neuen Kraftabstiegs werden vollständig unter Tage in einer für Hochdruckanlagen untypisch schwierigen Geologie hergestellt. Mit den Vortriebsarbeiten für die gesamt 4.000 m langen Stollen und Schächte wurde im März 2012 begonnen; im Juni 2013 wurden diese erfolgreich abgeschlossen. Bei den Bauverfahren hat man dabei einerseits auf die bewährten Methoden der NÖT und andererseits auf die moderne Technik des maschinellen Vortriebs gesetzt. Nach Fertigstellung der Felshohlraumbauten wird das Kernstück des neuen Kraftabstiegs, der 1.430 m lange Druckschacht, mit einer dickwandigen Panzerung ausgekleidet und hinterbetoniert.
Construction shaft of the Koralm Tunnel lot KAT 2 – a challenge in structural analysis, geotechnics and logistics / Der Bauschacht des Koralmtunnels Baulos KAT 2 – eine statische, geotechnische und logistische Herausforderung
Authors: Moritz Bernd , Radoncic Nedim , Helmberger Albert , Uschan Robert 
Published: October 2013

AbstractThe paper deals with the challenge on structural analysis, logistics as well as on geotechnical aspects during sinking of an approximately 60 m deep construction shaft with a cross‐sectional area of about 720 m2 at the Koralm Tunnel lot KAT 2. Numerical 3D simulations were used for the structural analysis. The results in terms of level of loading of the support measures and the displacements served as a basis for predicting the system behaviour of the shaft. During sinking, the behaviour of the shaft and surface was continuously monitored within the geotechnical safety management by means of 3D displacement measurements, measurement of strains in the shotcrete lining and measurements of pile inclinometers. Thereby a continuous target‐performance comparison was accomplished. Special characteristics in the design and construction phase are illustrated and discussed.Der Beitrag behandelt die Herausforderung an die statische Berechnung, die Logistik im Zuge des Abteufens sowie an die Geotechnik beim rund 60 m tiefen Bauschacht des Koralmtunnels Baulos KAT 2 mit einer Querschnittsfläche von insgesamt ca. 720 m2. Die statische Berechnung erfolgte mittels numerischer 3D‐Simulationen. Die Ergebnisse in Bezug auf Auslastungsgrad der Stützmittel und Verschiebungsausmaß dienten in weiterer Folge als Basis für die Prognose des Systemverhaltens des Schachtbauwerks. Im Zuge des Abteufvorgangs erfolgte im Rahmen des Geotechnischen Sicherheitsmanagements eine lückenlose Überwachung des Schachtbauwerks über 3D‐Verschiebungsmessungen an der Oberfläche und der Schachtlaibung, Messung von Dehnungen in der Spritzbetonaußenschale sowie über Bohrpfahlinklinometer. Dabei wurde ein ständiger Soll‐Ist‐Vergleich geführt. Besonderheiten in der Planung und Bauausführung werden aufgezeigt und diskutiert.
Competitive pumped‐storage projects with vertical pressure shafts without steel linings / Konkurrenzfähige Pumpspeicherwerkprojekte dank ungepanzerter, vertikaler Druckschächte
Authors: Schleiss Anton 
Published: October 2013

AbstractFor the highly loaded pressure tunnels and shafts that are used for the extension of storage power plants with pumped storage and to increase installed capacity, alignments of the waterway system with high overburden are of great importance from the economical and safety points of view. With the development of the raise‐boring method, vertical pressure shafts can now be drilled up to 800 m in one step.Considering rock cover, the use of vertical pressure shafts can enable optimal alignments. If the vertical shaft is located deep enough in the rock mass and safety against hydraulic jacking can be ensured, no steel liner is required in the shaft as long as rock permeability is low, and a reinforced concrete lining is sufficient. This is designed in order to limit crack widths and thus keep water losses below acceptable values. In view of highly increasing steel prices, such a concept results in economic and competitive pumped‐storage projects.Bei hochbeanspruchten Druckstollen und Druckschächten, wie diese bei der Erweiterung von Speicherkraftwerken mit Pumpspeicherwerken und durch Leistungserhöhungen vorkommen, sind tiefliegende Linienführungen der Triebwassersysteme aus wirtschaftlichen und sicherheitstechnischen Gründen von größter Bedeutung. Mit der Entwicklung des Raise‐Boring‐Verfahrens können heute Vertikalschächte bis gegen 800 m in einer einzigen Etappe ausgeführt werden. Dadurch ergeben sich bezüglich Felsüberdeckung optimale Linienführungen. Falls der Schacht genügend tief im Gebirge angeordnet wird und somit die Sicherheit gegen hydraulischen Gebirgsbruch gewährleistet ist, kann bei wenig durchlässigen Felsformationen auf eine Stahlpanzerung verzichtet werden. Eine bewehrte Betonauskleidung ist ausreichend, deren Bewehrung so bemessen ist, dass die Rissweiten und somit die Wasserverluste auf zulässige Werte beschränkt werden. Anbetracht der stark angestiegenen Stahlpreisen führt dieses Konzept zu wirtschaftlichen und konkurrenzfähigen Pumpspeicherwerkprojekten.
New Steroidal Saponins from the Leaves of Yucca elephantipes
Authors: Zhang Ying , Yang Chong‐Ren , Zhang Ying‐Jun 
Published: October 2013

AbstractTwo new spirostanol saponins, namely elephanosides G and H (1 and 2, resp.) were isolated from the leaves of Yucca elephantipes (Agavaceae), together with the two known furostanol saponins 3 and 4 and the six known flavonoid O‐ and C‐glycosides 5–10. The new structures were elucidated as (3β,25S)‐spirost‐5‐en‐3‐yl O‐β‐D‐glucopyranosyl‐(1→3)‐O‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐galactopyranoside (1) and (3β,5β,25R)‐3‐[(2‐O‐β‐D‐glucopyranosyl‐β‐D‐galactopyranosyl)oxy]spirostan‐12‐one (2) on the basis of detailed spectroscopic analysis and acidic hydrolysis.
Molecular Chirality in Chemistry and Biology: Historical Milestones
Authors: Gal Joseph 
Published: October 2013

AbstractBeginning early in the 19th century, developments in crystallography, optics, and chemistry in France set the stage for the discovery of molecular chirality by Louis Pasteur in 1848. He found that the crystallization of the sodium ammonium salt of ‘paratartaric acid’, a mysterious ‘isomer’ of natural (+)‐tartaric acid (TA), produced two different crystal types that were non‐superimposable mirror‐image forms of each other. He separated the two types and found their optical rotations in solution opposite in direction and equal in absolute magnitude. This led him to conclude that paratartaric acid is a combination of two mirror‐image molecule types of TA that are ‘dissymmetric’, an existing term he adapted to the connotation of today's ‘chiral’. In 1857, he found that the two enantiomers of TA were metabolized by a microorganism at drastically different rates, and thereby discovered biological enantioselectivity. In 1886, Italian chemist Arnaldo Piutti discovered D‐asparagine and found that it tasted intensely sweet, in contrast to the known L‐asparagine which had no taste. This was the discovery of stereoselectivity at biological receptors. As a result of advances in stereoselective synthesis and enantioselective chromatography during the last decades of the 20th century, in the 1990s the importance of molecular chirality in drug action and disposition began to receive serious attention from drug‐regulatory authorities and the pharmaceutical industry, the overall result of which has been the near‐complete disappearance of racemic drugs as newly introduced pharmaceuticals.
Modelling the impact of stormwater source control infiltration techniques on catchment baseflow
Authors: Hamel Perrine , Fletcher Tim D. 
Published: October 2013

AbstractStormwater management increasingly recognises the need to emulate, to the maximum extent possible, the flow regime of receiving waters in their pre‐development state. Hydrological models play a central role in assessing the catchment‐scale impacts of alternative stormwater management strategies. However, because of the complexity of physical processes involved in urban hydrology, particularly subsurface flows, the predictive performance of such models is often low. We investigated how the structure of hydrological models influenced the prediction of urbanisation and stormwater management impacts on baseflow. We calibrated three conceptual models of the same reference catchment and compared the modelled flow regime from different stormwater management scenarios, using each of the three model structures. Scenarios were assessed using six metrics, characterising the whole streamflow regime and in particular baseflow. Although the three models of the reference catchment represented the observed hydrograph well, the most complex structure developed using a thorough diagnostic of the catchment behaviour better captured the change in hydrological regime during dry years. Predictions of baseflow changes due to urbanisation varied significantly according to the model structure. Similarly, the models showed distinct responses to the stormwater management scenarios applied, especially for scenarios involving infiltration of stormwater at source. Our results confirm the importance of predicting the consequences of land use changes with conceptual models that are consistent with the hydrological behaviour of the study catchment. Future work should help to quantify the uncertainties due to model structure and thus provide practical guidance to the use of catchment models for assessing stormwater management strategies. Copyright © 2013 John Wiley & Sons, Ltd.
Low‐Frequency Ultrasound Effects on Intracellular Barriers in Nonviral Gene Delivery Processes
Authors: Goldian Irit , Traitel Tamar , Goldbart Riki , Kost Joseph 
Published: October 2013

AbstractGene therapy, the expression in cells of genetic material with therapeutic activity, has emerged as a promising approach for the treatment or prevention of human diseases. At the present time, major somatic gene‐transfer approaches employ either viral or nonviral vectors. Nonviral vectors are less efficient at introducing and maintaining foreign gene expression, but have the profound advantage of being nonpathogenic and nonimmunogenic. In this study, we aimed to develop an efficient nonviral gene delivery system in which low‐frequency ultrasound (LFUS) was applied to enhance gene expression of polyplexes formed with poly(2‐dimethylaminoethyl methacrylate) and plasmid encoding for green fluorescent protein. Ultrasound (US), and in particular LFUS, can cause temporary membrane permeabilization and thereby enhance drug and gene entrance into viable cells. We evaluated possible additional favorable effects of LFUS on the polyplex transfection process, such as overcoming intracellular barriers. We found that pDMAEMA protected the plasmid DNA from ultrasonic degradation. Atomic force microscopy analysis also confirmed that the LFUS did not change the polyplexes’ morphology. We also attained an insight into the structure of polyplexes during LFUS exposure and found that LFUS induced a temporary partial detachment between the polymer chains and the plasmid. In addition, LFUS application on ovarian carcinoma cells transfected with the polyplexes induced a 27% enhancement in transfection efficiency. Based on these results, we propose that LFUS enhances the decomplexation of the polyplexes, and therefore, can be used to optimize transfection efficiency.