bluuebunny/crossref_metadata_2025_split huggingface dataset:
Volatiles of Curcuma manggaVal. & Zijp (Zingiberaceae) from Malaysia
Authors: Wahab Ikarastika Rahayu Abdul , Blagojević Polina D. , Radulović Niko S. , Boylan Fabio 
Published: November 2011

AbstractAnalysis by GC and GC/MS of the essential oil obtained from Malaysian Curcuma mangga Val. & Zijp (Zingiberaceae) rhizomes allowed the identification of 97 constituents, comprising 89.5% of the total oil composition. The major compounds were identified as myrcene (1; 46.5%) and β‐pinene (2; 14.6%). The chemical composition of this and additional 13 oils obtained from selected Curcuma L. taxa were compared using multivariate statistical analyses (agglomerative hierarchical cluster analysis and principal component analysis). The results of the statistical analyses of this particular data set pointed out that 1 could be potentially used as a valuable infrageneric chemotaxonomical marker for C. mangga. Moreover, it seems that C. mangga, C. xanthorrhiza Roxb., and C. longa L. are, with respect to the volatile secondary metabolites, closely related. In addition, comparison of the essential oil profiles revealed a potential influence of the environmental (geographical) factors, alongside with the genetic ones, on the production of volatile secondary metabolites in Curcuma taxa.
Critical Evaluation of Different Mass Transfer Models Taking Zinc Extraction as an Example
Authors: Klapper P. , Repke J.‐U. , Raatz S. 
Published: November 2011

AbstractDifferent mass transfer models were evaluated on the basis of zinc extraction with the liquid ion exchanger di(2‐ethylhexyl)phosphoric acid. Comparison of the models showed that the film model inadequately describes the time dependence of zinc concentration in aqueous solution. The best match of the measured time‐concentration profiles was achieved by adapting the film‐penetration model. Studies were carried out in a stirred cell with a planar interface stabilized by the mixing conditions. Under the chosen experimental conditions mass transfer was limited by zinc transfer in the aqueous phase. The mass transfer equations of each model were solved analytically using empirical correlations for the modeling parameters.
Ultrasonic Desorption of CO2 – A New Technology to Save Energy and Prevent Solvent Degradation
Authors: Gantert S. , Möller D. 
Published: November 2011

AbstractA central concern of future research activities in the field of carbon capture and storage is the reduction of energy demand for solvent regeneration. This also includes, besides the development of more efficient CO2 absorbents, the exploration of alternative desorption methods. The stripping process is generally regarded as the state‐of‐the‐art in amine scrubbing, although significant amounts of heat are required for steam generation in the stripper. Against this background, a new desorption technique on the basis of pressureless amine scrubbing is under development, in which an ultrasonic field is used to accelerate the CO2 desorption. With the new ultrasound method, applied for a patent, desorption of CO2 can be performed at temperatures below 80 °C. This special feature of the ultrasonic‐assisted CO2 degassing can be applied advantageously together with weakly binding CO2 absorbents which are in use in connection with a high CO2 partial pressure in the raw gas.
Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies
Authors: Behenna Douglas C. , Mohr Justin T. , Sherden Nathaniel H. , Marinescu Smaranda C. , Harned Andrew M. , Tani Kousuke , Seto Masaki , Ma Sandy , Novák Zoltán , Krout Michael R. , McFadden Ryan M. , Roizen Jennifer L. , Enquist John A. , White David E. , Levine Samantha R. , Petrova Krastina V. , Iwashita Akihiko , Virgil Scott C. , Stoltz Brian M. 
Published: November 2011

Abstractα‐Quaternary ketones are accessed through novel enantioselective alkylations of allyl and propargyl electrophiles by unstabilized prochiral enolate nucleophiles in the presence of palladium complexes with various phosphinooxazoline (PHOX) ligands. Excellent yields and high enantiomeric excesses are obtained from three classes of enolate precursor: enol carbonates, enol silanes, and racemic β‐ketoesters. Each of these substrate classes functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target‐directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner‐sphere mechanism involving binding of the prochiral enolate nucleophile directly to the palladium center.
Benzo[e]pyrene Skeleton Dipyrylium Dication with a Strong Donor–Acceptor–Donor Interaction, and Its Two‐Electron Reduced Molecule
Authors: Rao Koya Prabhakara , Kondo Mio , Sakamoto Ryota , Kusamoto Tetsuro , Nishikawa Michihiro , Kume Shoko , Nihei Masayuki , Oshio Hiroki , Nishihara Hiroshi 
Published: November 2011

AbstractThe donor–acceptor–donor (D–A–D) conjugated molecules 1,4‐bis(diarylaminophenylethynyl)anthraquinone (1,4‐Am2Aq) and 1,4‐bis(ferrocenylethynyl)anthraquinone (1,4‐Fc2Aq), undergo a double proton cyclization reaction with bis(trifluoromethanesulfone)imide acid (TFSIH) to yield 1,4‐bis(diarylaminophenyl or ferrocenyl) dipyrylium salts [1,4‐R2Pyl2](TFSI)2 (R=Am or Fc) with novel planar pentacyclic structures similar to the aromatic benzo[e]pyrene‐type skeleton. [1,4‐Am2Pyl2](TFSI)2 could be reduced to give the neutral molecule [1,4‐Am2Pyl2]0, which is stable and maintains the benzo[e]pyrene‐type skeleton. To the best of our knowledge, this is the first oxygen‐atom‐containing polycyclic aromatic hydrocarbon with 22 (4n+2) π‐electrons. The obtained condensed‐ring benzo[e]pyrene‐type skeleton compounds show physical and chemical properties that are significantly different from those of [1,5‐Am2Pyl2](TFSI)2, which has a perylene‐type skeleton.
Design and Photophysical Properties of Zinc(II) Porphyrin‐Containing Dendrons Linked to a Central Artificial Special Pair
Authors: Brégier Frédérique , Aly Shawkat M. , Gros Claude P. , Barbe Jean‐Michel , Rousselin Yoann , Harvey Pierre D. 
Published: November 2011

AbstractThe click chemistry synthesis and photophysical properties, notably photo‐induced energy and electron transfers between the central core and the peripheral chromophores of a series of artificial special pair–dendron systems (dendron=G1, G2, G3; Gx=zinc(II) tetra‐meso‐arylporphyrin‐containing polyimides) built upon a central core of dimethylxanthenebis(metal(II) porphyrin) (metal=zinc, copper), are reported. The dendrons act as singlet and triplet energy acceptors or donors, depending on the dendrimeric systems. The presence of the paramagnetic d9 copper(II) in the dendrimers promotes singlet–triplet energy transfer from the zinc(II) tetra‐meso‐arylporphyrin to the bis(copper(II) porphyrin) unit and slow triplet–triplet energy transfer from the central bis(copper(II) porphyrin) fragment to the peripheral zinc(II) tetra‐meso‐arylporphyrin. If bis(zinc(II) porphyrin) is the central core, evidence for chain folding is observed; this is unambiguously demonstrated by the presence of triplet–triplet energy transfer in the heterobimetallic systems, a process that can only occur at short distances.
Blue Emitting 3 π–2 Spiro Terfluorene–Indenofluorene Isomers: A Structure–Properties Relationship Study
Authors: Poriel Cyril , Rault‐Berthelot Joëlle , Thirion Damien , Barrière Frédéric , Vignau Laurence 
Published: November 2011

AbstractTwo novel terfluorenyl derivatives, 2,2′′,7,7′′‐tetrakis(9,9‐dioctyl‐9H‐fluoren‐2‐yl)dispiro[fluorene‐9,11′‐indeno‐(2,1‐a)‐fluorene‐12′,9′′‐fluorene] ((2,1‐a)‐DST‐IF) and 2,2′′,7,7′′‐tetrakis(9,9‐dioctyl‐9H‐fluoren‐2‐yl)dispiro‐ [fluorene‐9,6′‐indeno‐(1,2‐b)‐fluorene‐12′,9′′‐fluorene] ((1,2‐b)‐DST‐IF) have been synthesized by two different synthetic approaches. These terfluorenyl derivatives possess a different central indenofluorene core, namely (2,1‐a)‐indenofluorene or (1,2‐b)‐indenofluorene, which imposes two distinct geometry profiles, and different structural environments for the terfluorenyl fluorophores that translates into drastically different optical and electrochemical properties for (2,1‐a)‐DST‐IF and (1,2‐b)‐DST‐IF. These properties have been carefully studied through a combined experimental and theoretical approach. The (2,1‐a)‐DST‐IF isomer has been successfully used as emitting layer in a blue single‐layer small‐molecule organic light‐emitting diode (SMOLED) and appears as the first example of a blue emission arising from intramolecular terfluorenyl excimers. Regarding the importance of terfluorenyl derivatives in organic electronics, the present structure–properties relationship study, may open new avenues in the design of efficient blue fluorophores.
An Unusual Organoyttrium Alkyl Complex Containing a [C5HMe3(η3‐CH2)‐C5H4N‐κ]− Ligand and an Elusive Cyclopentadienide‐Based Scandium Tuck‐Over Zwitterion Obtained by CH Bond Activation
Authors: Jian Zhongbao , Cui Dongmei 
Published: November 2011

AbstractThe acid–base reaction between Y(CH2SiMe3)3(thf)2 and the pyridyl‐functionalized cyclopentadienyl (Cp) ligand C5Me4HC5H4N (1 equiv) at 0 °C afforded a mixture of two products: (η5:κ‐C5Me4C5H4N)Y(CH2SiMe3)2(thf) (1 a) and (η5:κ‐C5Me4C5H4N)2YCH2SiMe3 (1 b), in a 5:2 ratio. Addition of the same ligand (2 equiv) to Y(CH2SiMe3)3(thf)2, however, generated 1 b together with the novel complex 1 c, the first well defined yttrium mono(alkyl) complex (η5:κ‐C5Me4C5H4N)[C5HMe3(η3‐CH2)‐C5H4N‐κ]Y(CH2SiMe3) containing a rare κ/η3‐allylic coordination mode in which the CH bond activation occurs unexpectedly with the allylic methyl group rather than conventionally on Cp ring. If the central metal was changed to lutetium, the equimolar reaction between Lu(CH2SiMe3)3(thf)2 and C5Me4HC5H4N exclusively afforded the bis(alkyl) product (η5:κ‐C5Me4C5H4N)Lu(CH2SiMe3)2(thf) (2 a). Similarly, the reaction between the ligand (2 equiv) and Lu(CH2SiMe3)3(thf)2 gave the mono(alkyl) complex (η5:κ‐C5Me4C5H4N)2LuCH2SiMe3 (2 b), in which no ligand redistribution was observed. Strikingly, treatment of Sc(CH2SiMe3)3(thf)2 with C5Me4HC5H4N in either 1:1 or 1:2 ratio at 0 °C generated the first cyclopentadienide‐based scandium zwitterionic “tuck‐over” complex 3, (η5:κ‐C5Me4C5H4N)Sc(thf)[μ‐η5:η1:κ‐C5Me3(CH2)‐C5H4N]Sc(CH2SiMe3)3. In the zwitterion, the dianionic ligand [C5Me3(CH2)‐C5H4N]2− binds both to Sc13+ and to Sc23+, in η5 and η1/κ modes. In addition, the reaction chemistry, the molecular structures, and the mechanism are also discussed in detail.
Stool DNA testing for the detection of pancreatic cancer
Authors: Kisiel John B. , Yab Tracy C. , Taylor William R. , Chari Suresh T. , Petersen Gloria M. , Mahoney Douglas W. , Ahlquist David A. 
Published: November 2011

AbstractBACKGROUND:Pancreatic cancer (PanC) presents at late stage with high mortality. Effective early detection methods are needed. Aberrantly methylated genes are unexplored as markers for noninvasive detection by stool testing. The authors aimed to select discriminant methylated genes and to assess accuracy of these and mutant KRAS in stool to detect PanC.METHODS:Nine target genes were assayed by real‐time methylation‐specific polymerase chain reaction (MSP) in bisulfite‐treated DNA from microdissected frozen specimens of 24 PanC cases and 30 normal colon controls. Archived stools from 58 PanC cases and 65 controls matched on sex, age, and smoking were analyzed. Target genes from fecal supernatants were enriched by hybrid capture, bisulfite‐treated, and assayed by MSP. KRAS mutations were assayed using the QuARTS technique.RESULTS:Areas under the receiver operating characteristics curves (AUCs) for tissue BMP3, NDRG4, EYA4, UCHL1, MDFI, Vimentin, CNTNAP2, SFRP2, and TFPI2 were 0.90, 0.79, 0.78, 0.78, 0.77, 0.77, 0.69, 0.67, and 0.66, respectively. The top 4 markers and mutant KRAS were evaluated in stool. BMP3 was the most discriminant methylation marker in stool. At 90% specificity, methylated BMP3 alone detected 51% of PanCs, mutant KRAS detected 50%, and combination detected 67%. AUCs for methylated BMP3, mutant KRAS, and combination in stool were 0.73, 0.75, and 0.85, respectively.CONCLUSIONS:This study demonstrates that stool assay of a methylated gene marker can detect PanC. Among candidate methylated markers discriminant in tissue, BMP3 alone performed well in stool. Combining methylated BMP3 and mutant KRAS increased stool detection over either marker alone. Cancer 2011;. © 2011 American Cancer Society.
Real‐time quality assessment for voice over IP
Authors: Yang Fuzheng , Jiang Liangliang , Li Xiao 
Published: November 2011

SUMMARYA nonintrusive packet layer model is proposed for quality assessment of Voice over Internet Protocol. Through a simple analysis on the packet headers of the bit‐stream, the information about the bit‐rate and lost status is obtained for each frame. Then the frame quality is measured in terms of coding distortion, frame loss, and contamination because of error propagation. Given the frame quality, a two‐level temporal pooling scheme is designed to predict the overall speech quality. Experimental results show that the proposed model is very accurate in quality assessment. Moreover, the proposed packet layer model is featured by its low complexity, which makes it very suitable for real‐time quality monitoring for Voice over Internet Protocol services. Copyright © 2011 John Wiley & Sons, Ltd.
Efficient bitstream extraction for scalable video based on simulated annealing
Authors: Wan Shuai , Yang Kaifang , Zhou Haiyong 
Published: November 2011

SUMMARYThis paper presents an efficient method for bitstream extraction for scalable video based on simulated annealing. Following the same spirit as annealing, the proposed method searches for the optimized combination of quality layers for extraction through slowly reducing the simulated temperature according to the characteristics of frames in different temporal levels. Experimental results show that the proposed method provides an optimized performance, which is significantly higher than that of the basic extraction method. When compared with the quality layer‐based extraction method in the reference software model of H.264/SVC (Joint Scalable Video Model), the proposed method can achieve a similar rate‐distortion performance with a significantly reduced computational complexity. Furthermore, the proposed method can obtain a more smoothed video quality, which is always preferable by the end user. Copyright © 2011 John Wiley & Sons, Ltd.
Defect structure and light‐induced scattering of Zr‐doped near‐stoichiometric Mn:Fe:LiNbO3 crystals grown by TSSG method
Authors: Xu Chao , Xu Lei , Leng Xuesong , Xu Yuheng , Yang Chunhui 
Published: November 2011

AbstractNear‐stoichiometric Mn:Fe:LiNbO3 crystals doped with various concentration of ZrO2 were grown by top seed solution growth (TSSG) method in the air atmosphere. The Zr concentration in the crystal was determined by inductively coupled plasma optical emission spectrometer. The defect structures were analyzed by means of ultraviolet‐visible and infrared transmittance spectra. The appearance of vibration peak at 3466 cm‐1 in infrared spectra manifested that Li/Nb ratio in crystals approached to stoichiometric proportion. The fundamental absorption edge represented continuous red‐shift which was discrepancy with congruent doped LiNbO3 crystals showed that doping ions possessed different location mechanism. The light‐induced scattering of the doped stoichiometric LiNbO3crystals were quantitatively scaled via incident exposure energy. The results demonstrated that Zr(2 mol%):Mn:Fe:LiNbO3 crystal had the weakest light‐induced scattering and the mechanism related to their defect structures was discussed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
First principle studies on molecular doping of ZnO thin films by As2O3
Authors: Sorgenfrei T. , Bachem K. H. , Schneider J. , Kirste L. , Kunzer M. , Fiederle M. 
Published: November 2011

AbstractThis work investigates the extrinsic molecular doping of zinc oxide (ZnO) thin films grown by plasma enhanced molecular beam epitaxy (P‐MBE). The dopant was thermally evaporated arsenic trioxide (formula: As2O3 in the solid state), which appears as As4O6 molecule in the gaseous phase. Cracking experiments of these As4O6 molecules were made using a radio frequency oxygen plasma. Structural, chemical and optical investigations were made with (High Resolution) X‐ray diffraction (HRXRD), secondary ion mass spectroscopy (SIMS) and photoluminescence (PL). These results show high incorporation rates (about 2x1018 cm‐3) and optical activity of the dopant. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A universal‐input high‐power‐factor power supply without electrolytic capacitor for multiple lighting LED lamps
Authors: Ma Hongbo , Lai Jih‐Sheng (Jason) , Feng Quanyuan , Yu Wensong , Zheng Cong 
Published: November 2011

SUMMARYThe AC–DC power supply for LED lighting application requires a long lifetime while maintaining high‐efficiency, high power factor and low cost. However, a typical design uses electrolytic capacitor as storage capacitor, which is not only bulky but also with short life span, thus hampering performance improvement of the entire LED lighting system. In this article, a SEPIC‐derived power factor correction topology is proposed as the first stage for driving multiple lighting LED lamps. Along with a relatively large voltage ripple allowable in a two‐stage design, the proposal of LED lamp driver is able to eliminate the electrolytic capacitor while maintaining high power factor and high efficiency. To further increase the efficiency of LED driver, we introduced and used the twin‐bus buck converter as the second‐stage current regulator with Pulse Width Modulation (PWM) dimming function. The basic operating principle and the deign consideration are discussed in detail. A 50‐W prototype has been built and tested to verify the proposal. Copyright © 2011 John Wiley & Sons, Ltd.
Cyclopropanation Reactions Mediated by Group 9 Metal Porphyrin Complexes (Eur. J. Inorg. Chem. 33/2011)
Authors: Intrieri Daniela , Caselli Alessandro , Gallo Emma 
Published: November 2011

AbstractThe cover picture shows the Monte Eyehorn (2131 m), Italy. The cyclopropanation of olefins mediated by porphyrin complexes of group IX metals has been reviewed, and several methodologies affording cyclopropanes with good diastereo‐ and enantioselectivity have been described. The efficiency of porphyrin complexes to reduce the activation barrier (as symbolically represented in the photo) allows the synthesis of a wide class of compounds bearing a large number of different substituents on the cyclopropane ring. An overview of the mechanistic aspects of these reactions, explored over the years to improve the performance of porphyrin‐catalysed cyclopropanations, has also been provided. Details are presented in the Microreview by E. Gallo et al. on p. 5071 ff.
Chiral Organomagnesiates as Dual Reagents for Bromine–Magnesium Exchange of 2‐Bromopyridine and Access to Chiral α‐Substituted 2‐Pyridylcarbinols
Authors: Catel Delphine , Chevallier Floris , Mongin Florence , Gros Philippe C. 
Published: November 2011

AbstractNew chiral ligand containing butyl and dibutylmagnesiates have been prepared from a range of ligands and their reactivity studied. The reagents were generally efficient in promoting the clean bromine–magnesium exchange of 2‐bromopyridine at room temperature and the subsequent reaction with aldehydes to afford α‐substituted 2‐pyridylcarbinols in good yields. (R,R)‐TADDOLate proved to be the best ligand, leading to acceptable to good enantioselectivities. To the best of our knowledge this is the first example of an organomagnesiate‐induced halogen–metal exchange followed by an enantioselective addition.
An Unexpected Result of the Reaction of Benzothioamide Derivatives with 2‐Aryl‐2‐bromoacetonitriles
Authors: Zali Boeini Hassan , Mobin Mehdi 
Published: November 2011

AbstractUnexpectedly, in the reaction of 2‐bromo‐2‐phenylacetonitrile derivatives with 2 mol‐equiv. of benzothioamide in DMSO, 3,5‐diaryl‐1,2,4‐thiadiazoles were obtained in excellent yields (83–90%) and in short reaction times (5–10 min). It is found that, in DMF, a quite different reaction takes place and 2,5‐diaryl‐1,3‐thiazol‐4‐amines are formed as the main products.
Efficient Synthesis of Tetrahydropyrimidines and Pyrrolidines by a Multicomponent Reaction of Dialkyl Acetylenedicarboxylates (=Dialkyl But‐2‐ynedioates), Amines, and Formaldehyde in the Presence of Iodine as a Catalyst
Authors: Das Biswanath , Kanth Boddu Shashi , Shinde Digambar Balaji , Kamble Vinod T. 
Published: November 2011

AbstractIodine was explored as an efficient catalyst for the synthesis of tetrahydropyrimidines 4 and pyrrolidines 5 by a multicomponent reaction of dialkyl acetylenedicarboxylates (=dialkyl but‐2‐ynedioates) 1, amines 2, and HCHO 3 at room temperature (Scheme). When the molar ratios of these substrates were 1 : 2 : 4 and 1 : 1 : 4, tetrahydropyrimidines and pyrrolidines were formed, respectively. The products were obtained in high yields (73–85%) within a short period of time (25–35 min).
Stereoselective Preparation of 3‐Amino‐2‐fluoro Carboxylic Acid Derivatives, and Their Incorporation in Tetrahydropyrimidin‐4(1H)‐ones, and in Open‐Chain and Cyclic β‐Peptides
Authors: Yoshinari Tomohiro , Gessier François , Noti Christian , Beck Albert K. , Seebach Dieter 
Published: November 2011

AbstractThe preparation of (2S,3S)‐ and (2R,3S)‐2‐fluoro and of (3S)‐2,2‐difluoro‐3‐amino carboxylic acid derivatives, 1–3, from alanine, valine, leucine, threonine, and β3h‐alanine (Schemes 1 and 2, Table) is described. The stereochemical course of (diethylamino)sulfur trifluoride (DAST) reactions with N,N‐dibenzyl‐2‐amino‐3‐hydroxy and 3‐amino‐2‐hydroxy carboxylic acid esters is discussed (Fig. 1). The fluoro‐β‐amino acid residues have been incorporated into pyrimidinones (11–13; Fig. 2) and into cyclic β‐tri‐ and β‐tetrapeptides 17–19 and 21–23 (Scheme 3) with rigid skeletons, so that reliable structural data (bond lengths, bond angles, and Karplus parameters) can be obtained. β‐Hexapeptides Boc[(2S)‐β3hXaa(αF)]6OBn and Boc[β3hXaa(α,αF2)]6‐OBn, 24–26, with the side chains of Ala, Val, and Leu, have been synthesized (Scheme 4), and their CD spectra (Fig. 3) are discussed. Most compounds and many intermediates are fully characterized by IR‐ and 1H‐, 13C‐ and 19F‐NMR spectroscopy, by MS spectrometry, and by elemental analyses, [α]D and melting‐point values.
Marie Curie: Pioneering Discoveries and Humanitarianism
Authors: Greer Edyta M. , Tolmachova Mariya 
Published: November 2011

AbstractMarie Skłodowska‐Curie, the first woman to win a Nobel Prize and the only person to be awarded the Nobel Prize twice in different scientific disciplines, is an inspiring figure. She discovered two new elements, polonium and radium, and was appointed as the first female professor at the University of Paris, when in most countries women did not yet have the right to vote. She serves as a role model for scholarly and humanitarian endeavors through what she attained in science, and through the hardships she had to overcome and the gender discrimination barriers faced by women scientists of that period, which she had to break. This article is a tribute to Marie Skłodowska‐Curie's achievements.