bluuebunny/crossref_metadata_2025_split huggingface dataset:
KHSO4 as an Efficient Catalytic System for the Regiospecific Nitration of Phenols with Metal Nitrates
Authors: Baghernejad Bita , Oskooie Hossein A. , Heravi Majid M. , Beheshtiha Yahia Sh. 
Published: March 2010

AbstractHighly regiospecific mononitration of phenol and substituted phenols was accomplished employing a metal nitrate and a catalytic amount of KHSO4 in acetonitrile. An exclusive ortho‐selectivity was observed with excellent yields. A variety of metal nitrates were used to obtain o‐nitrophenols exclusively in good to excellent yields. The use of KHSO4 is key for the selectivity observed.
Fast and Efficient Nitration of Salicylic Acid and Some Other Aromatic Compounds over H3PO4/TiO2‐ZrO2 Using Nitric Acid
Authors: Kalbasi Roozbeh Javad , Massah Ahmad Reza , Zamani Farzad , Javaherian Naghash Hamid 
Published: March 2010

AbstractTiO2‐ZrO2 (1/1)‐surf with Ti and Zr molar ratio of 1/1 was prepared with surfactant through a sol‐gel method. The optimum experimental condition was investigated for nitration of salicylic acid. Then, a number of nitration reactions were carried out with a variety of aromatic compounds in the optimum condition. The 25 wt% H3PO4/TiO2‐ZrO2 (1/1)‐surf catalyst showed good selectivity and yield in a short time for the nitration of salicylic acid and some other aromatic compounds.
A Modified and Green Procedure for the Synthesis of β‐Amido Ketones Using a Br?nsted‐Acidic Ionic Liquid as Novel and Reusable Catalyst
Authors: Davoodnia Abolghasem , Heravi Majid M. , Rezaei‐Daghigh Leila , Tavakoli‐Hoseini Niloofar 
Published: March 2010

AbstractA green and improved method for the synthesis of β‐amido ketones through one‐pot multi‐component reaction of an enolizable ketone, aryl aldehyde, acetonitrile or benzonitrile in the presence of trimethylsilyl chloride using 3‐methyl‐1‐(4‐sulfonic acid)butylimidazolium hydrogen sulfate [(CH2)4SO3HMIM][HSO4], a Br?nsted‐acidic ionic liquid, as an effective and recyclable catalyst is described. The present methodology offers several advantages such as simple procedure with an easy work‐up, relatively short reaction time, and good to excellent yields.
Highly Efficient and Regio‐selective Glucosylation of 25(S) Ruscogenin by Gliocladium deliquescens NRRL1086
Authors: Chen Naidong , Zhang Jian , Liu Jihua , Yu Boyang 
Published: March 2010

AbstractA new steroidal glycoside, 25(S) ruscogenin 1‐O‐β‐D‐glucopyranoside (2) was obtained through the microbial transformation of 25(S) ruscogenin (1) by G. deliquescens NRRL1086 in 54% isolated yield. The structure of the product was elucidated by IR, MS and NMR spectra. This is the first report on the preparation of steroidal saponins by microbial transformation.
Ionic Liquid‐coordinated Ytterbium(III) Sulfonate Catalyzed Michael Addition of Indoles to Electron‐deficient Nitroolefins
Authors: Shen Wei , Wang Limin , Tang Jun , Qian Zhenhua , Tong Xiaofeng 
Published: March 2010

AbstractThe Michael addition of indoles to electron‐deficient nitroolefins was effectively catalyzed by an ionic liquid‐coordinated ytterbium(III) sulfonate catalyst. The recycling procedure of the catalyst was very simple without extraction with water, and the catalyst was reused for five times without any loss of its catalytic activity. Furthermore, to demonstrate the application of this methodology, the Pictet‐Spengler reaction was chosen and successfully carried out in the mixture of Br?nsted‐acidic ionic liquid and [bmim]BF4.
Design, Synthesis and Insecticidal Activities of Novel N‐Oxalyl Derivatives of Neonicotinoid Compound
Authors: Zhao Yu , Wang Gang , Li Yongqiang , Wang Suhua , Li Zhengming 
Published: March 2010

AbstractTen novel neonicotinoid derivatives containing N‐oxalyl groups were designed and synthesized, and their structures were characterized by 1H NMR, MS, IR, elemental analysis and single crystal X‐ray diffraction analysis. The insecticidal activities of the new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal activities.
Synthesis of 1,4‐Dihydropyridines Using Ce(SO4)2‐SiO2as Catalyst under Solvent‐free Conditions
Authors: Pei Wen , Wang Qin , Li Xiaonian , Sun Li 
Published: March 2010

AbstractA facile and efficient one‐pot synthesis of 1,4‐dihydropyridines from aldehyde, 1,3‐dicarbonyl compounds and ammonium acetate in the presence of Ce(SO4)2‐SiO2at 80°C under solvent‐free conditions is described. Compared with the classical Hantzsch reaction, this novel method consistently has the advantages of excellent yields and short reaction time.
Evaluation of the Surface ECG in Detecting Isthmus Conduction Block after Ablation of Typical Atrial Flutter
Authors: Yan Su‐hua , Cheng Wen‐juan , Chen Ming‐you , Xue Mei , Hu He‐sheng 
Published: March 2010

AbstractObjectivesTo investigate the value of changes in P wave morphology and duration detected by surface electrocardiogram (ECG) during proximal coronary sinus (PCS) and low lateral right atrial (LLRA) stimulation as a marker for complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation.MethodsMorphology, duration, and ratio of a positive terminal P wave were estimated in 52 typical atrial flutter patients before and after radiofrequency catheter ablation (RFCA).ResultsAtrial flutter ablation resulted in a complete bidirectional isthmus block in all 52 patients. The terminal portion of the P wave towards a positive morphology was detected in 90.7% (47/52) patients both during PCS and LLRA stimulation. These changes were predominantly observed in the inferior leads. Positive morphological changes of the terminal P wave portion and the measured P wave ratio (40% ± 12%) in the inferior leads indicating bidirectional isthmus conduction block with a sensitivity of 87.5% and a specificity of 91.7% were observed. An increment of 20 ms or more in P wave duration during the PCS stimulation and 10 ms or more during the LLRA stimulation indicating the conduction block with a sensitivity of 90% and a specificity of 100%.ConclusionsThe variation of P wave morphology and duration in inferior leads of the surface ECG is a helpful technique to assess the complete bidirectional isthmus conduction block in the procedure of typical atrial flutter ablation. Copyright © 2010 Wiley Periodicals, Inc.
Early Detection of Left Ventricular Dysfunction with Strain Imaging in Thalassemia Patients
Authors: Bilge Ahmet Kaya , Altinkaya Engin , Ozben Beste , Pekun Figen , Adalet Kamil , Yavuz Selim 
Published: March 2010

AbstractBackgroundIron‐mediated cardiomyopathy is the main cause of death in thalassemia patients. Early detection of cardiac abnormalities is important as aggressive chelation therapy may improve prognosis in these patients. The aim of this study is to evaluate left ventricular (LV) functions by tissue velocity imaging (TVI) and strain imaging (SI) in thalassemia patients without overt heart failure.MethodsAt total of 32 patients with β‐thalassemia major (mean age: 24.2±8.0 y, 22 male) and 25 healthy controls (mean age: 22.8±2.1 y, 20 male) were included. Conventional echocardiography, TVI, and SI were performed on all subjects. Tissue velocity imaging and SI measures included peak systolic, early and late diastolic myocardial velocities, peak systolic strain and strain rate, and early and late diastolic strain rate at the basal segments of the LV lateral and septal walls.ResultsThere were no significant differences in LV ejection fraction and fractional shortening between the groups. However, systolic myocardial velocity of the lateral wall and systolic strain and strain rate of the septal and lateral walls were significantly lower in thalassemia patients. There was a significant negative correlation between LV mass index and systolic myocardial velocity of the lateral wall (r = − 0.29, P = .045) and septal systolic strain (r = − 0.45, P < .001).ConclusionThalassemia patients have regional systolic dysfunction in the LV lateral and septal walls, even if they do not have overt heart failure. Strain imaging is helpful in early detection of LV systolic dysfunction in thalassemia patients. Copyright © 2010 Wiley Periodicals, Inc.
Improved synthesis of DOTA tetraamide ligands for lanthanide(III) ions: A tool for increasing the repertoire of potential PARACEST contrast agents for MRI and/or fluorescent sensors
Authors: De León‐Rodríguez Luis M. , Viswanathan Subha , Sherry A. Dean 
Published: March 2010

AbstractThe synthesis of new DOTA tetraamide (DOTAMR4) compounds is of great interest given their application in the formation of Ln(III) complexes as potential PARACEST contrast agents in MRI or fluorescent molecular probes. In this context amino acid and peptide DOTAMR4 derivatives are particularly attractive since the amino‐acid and/or peptide moiety can show responsive properties dependent on a given stimuli which might translate to changes in water exchange rates of the corresponding Ln(III) complex. Current synthesis of DOTAMR4 derivatives is typically carried out by reacting haloacetamide intermediates with cyclen. However, this method fails to generate the tetra‐substituted products when bulky substituents are present in the haloacetamide and in some cases this intermediate cannot be prepared by conventional acylation procedures limiting the number of DOTAMR4 compounds available for study. As a solution to these limitations, an improved methodology for the synthesis of DOTAMR4 by coupling DOTA to an appropriate amine containing reagent (i.e. protected amino‐acids with the α‐amino group free) is presented in this work. Several DOTAMR4 derivatives which are difficult or impossible to prepare with the traditional methodologies were easily obtained starting with DOTA. A new protocol was derived using this methodology for the solution‐phase synthesis of DOTA peptide derivatives. With this methodology, many other DOTAMR4 peptide and non‐peptide derivatives have been prepared in our laboratories with several of these new compounds showing interesting properties for molecular imaging. Copyright © 2010 John Wiley & Sons, Ltd.
Environmental Effects in Computational Spectroscopy: Accuracy and Interpretation
Authors: Pedone Alfonso , Biczysko Malgorzata , Barone Vincenzo 
Published: March 2010

AbstractSpectroscopic techniques are valuable tools for understanding the structure and dynamics of complex systems, such as biomolecules or nanomaterials. Most of the current research is devoted to the development of new experimental techniques for improving the intrinsic resolution of different spectra. However, the subtle interplay of several different effects acting at different length and time scales still makes the interpretation and analysis of such spectra a very difficult task. In this respect, computational spectroscopy is becoming a needful and versatile tool for the assignment and interpretation of experimental spectra. It is in fact possible nowadays to model with relatively high accuracy the physical–chemical properties of complex molecules in different environments, and to link spectroscopic evidence directly to the structural and dynamical properties of optically or magnetically active solvated probes. In this Review, significant steps toward the simulation of entire spectra in condensed phases are presented together with some basic aspects of computational spectroscopy, which highlight how intramolecular and intermolecular degrees of freedom influence several spectroscopic parameters.
CBr4 as precursor for VPE growth of cubic silicon carbide
Authors: Watts B. E. , Bosi M. , Attolini G. , Battistig G. , Dobos L. , Pécz B. 
Published: March 2010

AbstractThis work presents a study of carbon tetrabromide (CBr4) as precursor to deposit 3C‐SiC on (001) and (111) Si by VPE technique at temperatures ranging between 1000 °C and 1250 °C. TEM, AFM and SEM results indicate that the epitaxy proceeds as a 3D growth of uncoalesced islands at low temperature, whereas a continuous crystalline layer with hillocks on top is obtained above 1200 °C. The hillocks observed at high temperature appear well faceted and their shape and orientation are analyzed in detail by AFM, showing a {311} preferred orientation. 3D island growth was suppressed by adding C3H8 to the precursor gases. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of ZnO nanotubes
Authors: Zhai Hongju , Zheng Jiahong , Yang Jinghai , Liu Yang , Gao Ming 
Published: March 2010

AbstractTubular ZnO nanostructures have been obtained via a hydrothermal method at low temperature (90 °C) without any catalysts or templates. The XRD measurement reveals that the tubes are single crystals with hexagonal wurtzite structure. SEM shows that the diameters of ZnO nanotubes ranged from 400 to 550 nm. The Raman and PL spectra indicate that oxygen vacancies or Zn interstitials are responsible for the green emission in the ZnO nanotubes. A possible growth mechanism on the formation of crystalline ZnO nanotubes has been presented. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of the complex perovskite ceramic oxide Ba2YZrO6‐d
Authors: Kumar V. R. , Wariar P. R. S. , Koshy J. 
Published: March 2010

AbstractNanocrystalline Ba2YZrO6‐dhas been successfully synthesized through a single step auto‐ignition combustion route. The samples were analyzed by powder X‐ray diffraction, transmission electron microscopy and Ultraviolet‐Visible spectroscopy. The XRD analysis revealed that the material has an ordered complex cubic perovskite structure. The basic optical properties and optical constants of the as‐prepared nanopowder of Ba2YZrO6‐dhave been reported for the first time. The spectral analysis revealed that the material is a wide band gap direct transition semiconductor with band gap of 3.70 eV at room temperature. The poor transmittance in ultraviolet but good transmittance in visible‐near infrared regions make the material potentially important for poultry protection and warming coatings, solar control, antireflection coatings and window layer in solar cells. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of different solvents on the habit of meta‐nitroaniline single crystals
Authors: Srinivasan K. , Kanimozhi S. 
Published: March 2010

AbstractThe habit of the organic non‐linear optical material meta‐nitroaniline (mNA) crystallized from different organic solvents such as acetone, benzene, ethyl acetate, n‐hexane, methanol and toluene were studied. Solubility of mNA in these solvents at various temperatures in the range between 288 and 323 K was determined by gravimetric method. Crystals were grown by restricted evaporation of solvents method. Solutions with different solvents having different chemical nature and polarity yielded crystals with different habits: one‐dimensional needles, two‐dimensional rhombic platelets and three‐dimensional octahedral. In addition, the mNA crystals show unidirectional growth behaviour along its polar [001] direction irrespective of the solvents used. All the grown crystals were found to be orthorhombic system with point group mm2 and space group Pbc21 which was confirmed by powder X‐ray diffraction study. Optical transmittance study showed that the grown mNA single crystals have optical transparency in the wavelength range between 430 and 1550 nm. SHG efficiency of the grown mNA crystal was 3 times grater than KDP. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
caTBUA: Context‐aware ticket‐based binding update authentication protocol for trust‐enabled mobile networks
Authors: You Ilsun , Lee Jong‐Hyouk , Kim Bonam 
Published: March 2010

AbstractExisting binding update (BU) authentication protocols do not consider context information, such as trust, location, and current time, when verifying a mobile node's care‐of address (CoA). Instead, the correspondent node executes its own CoA validation in spite of facing a highly trusted situation or simply bypasses the CoA validation, making it difficult to maintain a reasonable trade‐off between security and efficiency. This paper applies the context‐aware concept to the BU process and proposes a new context‐aware ticket‐based binding update authentication (caTBUA) protocol. The proposed protocol dynamically performs an appropriate CoA validation based on the context information to achieve a good balance between security and efficiency. Utilizing numerical analysis to compare the performance of the proposed protocol to that of existing authentication protocols in terms of authentication cost and authentication message transmission latency confirmed that the proposed caTBUA protocol yields a better performance than the existing BU authentication protocols. Copyright © 2010 John Wiley & Sons, Ltd.
Site‐Selective Ser‐Hydrolase Labelling with a Luminescent Organometallic NCN–Platinum Complex
Authors: Wieczorek Birgit , Lemcke Bart , Dijkstra Harm P. , Egmond Maarten R. , Klein Gebbink Robertus J. M. , van Koten Gerard 
Published: March 2010

AbstractThe synthesis, spectroscopic properties and protein‐binding studies of a novel luminescent organometallic NCN–platinum complex are described. The luminescent organometallic complex was linked to a serine hydrolase reactive phosphonate group by means of click chemistry, and was exploited in serine hydrolase specific‐binding studies using gel electrophoresis. The NCN–platinum protein label was found to be a robust dye with absorbance and emission maxima between 374–380 and 482–493 nm, respectively, and quantum yields between 0.04 and 0.15.
Self‐Assembled Lanthanide Salicylaldimines with a Unique Coordination Mode
Authors: Kaczmarek Małgorzata T. , Kubicki Maciej , Mondry Anna , Janicki Rafał , Radecka‐Paryzek Wanda 
Published: March 2010

AbstractNew lanthanide salicylaldimine complexes of the formula [Ln(H2L)3(NO3)3](H2L), where Ln = La3+ (1), Nd3+ (2), Eu3+ (3), Gd3+ (4), Ho3+ (5), Er3+ (6), Tb3+ (7) or Yb3+ (8), and H2L = N,N′‐bis(salicylidene)‐4‐methyl‐1,3‐phenylenediamine, were formed in a self‐assembly process involving the lanthanide template‐induced one‐step [2+1] Schiff base condensation reaction between salicylaldehyde and 4‐methyl‐1,3‐phenylenediamine. The unusual coordination pattern of salen‐type ligands in these complexes, in which the three potentially tetradentate N2O2 salicylaldimines function as undeprotonated, monodentate, exclusively O‐donor ligands without involving the nitrogen atoms in the coordination environment, was proved by single‐crystal X‐ray diffraction analysis and correlated with spectroscopic characterization. In this species with the nine‐coordinate distorted tricapped trigonal prism geometry, the nitrates act as bidentate chelators occupying six coordination sites and leaving the remaining sites available for salicylaldimine ligands formed in situ in the template process. The additional salicylaldimine molecule acts as a guest for the salicylaldimine complex host and stabilizes the overall self‐assembled supramolecular network.
Synthesis of a Novel Taxa‐Oxa‐Sugar Hybrid Core Structure by Tandem Cross‐Enyne Metathesis/IMDA
Authors: Nandurdikar Rahul S. , Subrahmanyam Ayyagari V. , Kaliappan Krishna P. 
Published: March 2010

AbstractThis paper describes our design and efforts in synthesizing new scaffolds with taxol‐eleutherobin hybrid core structures and a taxol‐sugar hybrid. The synthesis of taxol‐eleutherobin hybrids involved the synthesis of the A‐ring fragment from carvone and the C‐ring fragment from either D‐mannose or D‐glucose. The Shapiro reaction was used as the key reaction to couple the A‐ and C‐ring fragments of these hybrid structures. Unfortunately, another key reaction (RCM) failed to form the B‐ring and essentially the core unit. However, a tandem enyne cross‐metathesis/intramolecular Diels–Alder strategy was utilized for the synthesis of a taxa‐oxa‐sugar hybrid.
Study on amino amides and enzyme kinetics of L‐asparaginase by MCE
Authors: Qiao Juan , Qi Li , Ma Huimin , Chen Yi , Wang Meixiang , Wang Dexian 
Published: March 2010

AbstractSeven kinds of amino amides including three synthetic arylglycine amides and four normal amino amides were successfully separated by MCE with LIF detector. Using micellar electrokinetic electrophoresis, the optimized separation of the seven kinds of amino amides was achieved with FITC as the labeling reagent and polyoxyethylene lauryl ether as the surfactant in 20.0 mM borate at pH 9.2. Under the optimized conditions, linearity of L‐asparagine was obtained in the range of 6.6×10−6–2.6×10−4 M; the detection limit (S/N=3) was 0.7 μM. The enzyme kinetic constants of L‐asparaginase using L‐asparagine as substrate were also determined by this method and the kinetic parameter Km and Vmax for the enzymatic hydrolysis of L‐asparagine were 442.0 μM and 69.9 μM/min, respectively.
Investigations on the migration behavior of insulin and related synthetic analogues in CZE, MEKC and MEEKC employing different surfactants
Authors: Haunschmidt Manuela , Ortner Karin , Hainz Katharina , Bradt Elke , Sternbauer Lukas , Buchberger Wolfgang , Klampfl Christian W. 
Published: March 2010

AbstractThe retention/migration behavior of insulin and five synthetic insulin analogues in CZE, MEKC and MEEKC employing seven different detergents within the latter two techniques has been investigated. Substantial changes in separation selectivity in MEKC could be observed for several insulins when moving from SDS to cholate‐based micellar systems. Customized separations could be achieved by using mixtures of SDS and deoxycholate. A similar effect could be observed in MEEKC although the overall quality of MEEKC separations was inferior to those obtained with MEKC.
Liposomes for entrapping local anesthetics: A liposome electrokinetic chromatographic study
Authors: Lokajová Jana , Laine Jaana , Puukilainen Esa , Ritala Mikko , Holopainen Juha M. , Wiedmer Susanne K. 
Published: March 2010

AbstractBupivacaine is a lipophilic, long‐acting, amide class local anesthetic commonly used in clinical practice to provide local anesthesia during surgical procedures. Several cases of accidental overdose with cardiac arrest and death have been reported since bupivacaine was introduced to human use. Recent case reports have suggested that Intralipid (Fresenius Kabi) is an effective therapy for cardiac toxicity from high systemic concentrations of, e.g. bupivacaine, even though the mechanism behind the interaction is not fully clear yet. Our long‐term aim is to develop a sensitive, efficient, and non‐harmful lipid‐based formulation to specifically trap harmful substances in vivo. In this study, the in vitro interaction of local anesthetics (bupivacaine, prilocaine, and lidocaine) with Intralipid or lipid vesicles containing phosphatidylglycerol, phosphatidylcholine, cardiolipin, cholesterol, and N‐palmitoyl‐D‐erythro‐sphingosine (ceramide) was determined by liposome electrokinetic chromatography. The interactions were evaluated by calculating the retention factors and distribution constants. Atomic force microscopy measurements were carried out to confirm that the interaction mechanism was solely due to interactions between the analytes and the moving pseudostationary phase and not by interactions with a stationary lipid phase adsorbed to the fused‐silica wall. The heterogeneity of the liposomes was also studied by atomic force microscopy. The liposome electrokinetic chromatography results demonstrate that there is higher interaction between the drugs and negatively charged liposome dispersion than with the commercial Intralipid dispersion.