bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonic Desorption of CO2 – A New Technology to Save Energy and Prevent Solvent Degradation
Authors: Gantert S. , Möller D.
Published: November 2011

A 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

α‐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

The 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

The 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

Two 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

The 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

BACKGROUND:

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

A 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

This 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

Near‐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

This 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

The 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

The 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

New 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

Unexpectedly, 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

Iodine 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

The 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

Marie 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.
Hydrological effects of water reservoirs on hydrological processes in the East River (China) basin: complexity evaluations based on the multi‐scale entropy analysis
Authors: Zhou Yu , Zhang Qiang , Li Kun , Chen Xiaohong
Published: November 2011

Using the multi‐scale entropy analysis (MSE), we study the effects of water reservoirs on the river flow records based on long streamflow series covering January 1, 1954 and December 31, 2009 at four representative hydrological stations, i.e. the Longchuan, the Heyuan, the Lingxia and the Boluo stations. Hydrological effects of two major water reservoirs, the Xinfengjiang and the Fengshuba water reservoirs, are evaluated. The results indicate that: (1) before the construction of the water reservoirs, the complexity of the streamflow series comes to be decreasing from the upper to the lower East River and which should be attributed to the topographical properties and buffering effects of the river channel; (2) construction of water reservoirs greatly increases the complexity degree of the hydrological processes, and this influence is subjected to a damping process with the increase of distance between the water reservoirs and the hydrological stations; (3) power generation is the major function of the water reservoirs in the East River basin. The results of this study should be of theoretical and scientific merits in terms of conservation of the ecological environment and also water resources management under the influences of climate changes and intensifying human activities. Copyright © 2011 John Wiley & Sons, Ltd.
Why Are Biological Systems Homochiral?
Authors: Percec Virgil , Leowanawat Pawaret
Published: November 2011

Self‐assembling and self‐organizable dendrons, dendrimers, and dendronized polymers produce chiral supramolecular architectures that have been developed as biological mimics. Here we review our work on the self‐assembly of homochiral, heterochiral, and racemic dendritic dipeptides, and address one of the most fundamental questions of biological systems: Why are biological systems homochiral and not heterochiral or racemic and, if they were heterochiral or racemic, how would they look and function by comparison with contemporary homochiral biological systems?
Spatiotemporal control over growth factor delivery from collagen‐based membrane
Authors: Li Xuemin , Wang Jianhua , Su Guanghao , Zhou Zhimin , Shi Jiawei , Liu Lingrong , Guan Man , Zhang Qiqing
Published: November 2011

Exogenous administration of growth factors has been identified as a potential therapeutic approach for healing wounds. A way to enhance the efficacy of growth factors would be to achieve spatiotemporal control over their delivery to desired sites for an extended period. In this study, we designed and prepared a kind of double‐layered collagen membrane, a dense layer and a loose layer, which incorporated basic fibroblast growth factor (bFGF)‐loaded chitosan‐heparin nanoparticles. The nanoparticles were prepared by polyelectrolyte gelation process and then were sandwiched between the two layers of collagen membrane. The release of model protein human serum albumin (HSA) from the double‐layered membrane was tracked by radio‐label assay, and the bioactivity of the growth factor on fibroblast cell (L929) was evaluated by MTT assay. The release of protein displayed a spatiotemporal control model and its release in undesired direction was lessened. The bFGF maintained the bioactivities after release from the membranes. Moreover, different release amounts of bFGF from the different layers of the membrane induced significant difference in cell proliferation when the cells were seeded on the different layers of membrane in vitro. This kind of double‐layered collagen membrane could have potential applications in the field of tissue repair due to the spatiotemporal control over growth factor delivery, the mild fabrication conditions, and the simple processes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Xylitol production by Candida tropicalis from corn cob hemicellulose hydrolysate in a two‐stage fed‐batch fermentation process
Authors: Li Minghua , Meng Xiumei , Diao Enjie , Du Fangling
Published: November 2011

BACKGROUND: Xylitol, a sugar alcohol widely used in food and pharmaceutical industries, can be produced through biological reduction of xylose present in hemicellulose hydrolysates by Candida tropicalis. However, the aeration rate and by‐products originating from hemicellulose hydrolysis strongly inhibit the production of xylitol in a fermentation process. A two‐stage fed‐batch fermentation system was developed to reduce these inhibitory effects and to improve xylitol production from corn cob hemicellulose hydrolysates by C. tropicalis.

RESULTS: Results of batch fermentations indicated that high xylitol production could be obtained from C. tropicalis at an initial xylose concentration of 80 g L−1 in corn cob hydrolysate medium at an aeration rate of 0.4 vvm at the micro‐aeration stage. In the two‐stage fed‐batch fermentation process, 96.5 g L−1 xylitol was obtained after 120 h, giving a yield of 0.83 g g−1 and a productivity of 1.01 g L−1 h−1, which were 12.16% and 65.57% higher than those in a batch fermentation.

CONCLUSION: High xylitol production can be achieved in a two‐stage fed‐batch fermentation process, in which the negative effects of aeration rate and inhibitory compounds on xylitol formation can be considerably reduced. Copyright © 2011 Society of Chemical Industry
Effect of feed intake level on ileal digestibilities of crude protein and amino acids in diets for piglets
Authors: Goerke Miriam , Eklund Meike , Sauer Nadja , Rademacher Meike , Piepho Hans‐Peter , Börner Christiane , Mosenthin Rainer
Published: November 2011

BACKGROUND: The study was conducted to determine the effect of graded levels of feed intake on apparent (AID) and standardized (SID) ileal digestibilities of crude protein (CP) and amino acids (AA) in diets for piglets. The piglets were surgically fitted with simple T‐cannulas at the distal ileum. The cornstarch–casein–soybean meal‐based diets were fed at three graded levels of feed intake corresponding to 30, 45 and 60 g kg−1 body weight (BW) per day.

RESULTS: The AID and SID of most AA were quadratically affected by the feed intake level (P⩽0.05). Initially, both AID and SID of most AA increased up to 1.9 percentage units as the feed intake level was increased from 30 to 45 g kg−1 BW. Thereafter, these AID and SID values decreased by 2.6 and 2.7 percentage units, respectively, as the feed intake level was further increased from 45 to 60 g kg−1 BW.

CONCLUSION: Because the voluntary feed intake is highly variable in piglets after weaning, comparison of ileal AA digestibilities between and within studies may be confounded by variations in feed intake level. Thus, when designing digestibility studies with piglets, a standardization of feed intake should be taken into consideration. Copyright © 2011 Society of Chemical Industry
Fatty acid composition of Celta pig breed as influenced by sex and location of fat in the carcass
Authors: Lorenzo José M , Montes Rosa , Purriños Laura , Cobas Noemi , Franco Daniel
Published: November 2011

BACKGROUND: The influence of sex and location of fat in the carcass on the fatty acid profile of Celta pigs was studied. Twenty pigs (10 castrated males and 10 females) from the Carballina line were used.

RESULTS: The fatty acids composition was predominated by monounsaturated fatty acids (MUFA; approximately 48% of total methyl esters), followed by saturated fatty acids (SFA; approximately 40% of total methyl esters) and, finally, polyunsaturated fatty acids (PUFA; approximately 12% of total methyl esters). The sex and location of fat in the carcass showed significant differences in PUFA and SFA content while both factors were not significantly different with respect to MUFA content. Linoleic, linolenic, eicosatrienoic and arachidonic fatty acids showed the largest difference among the three locations (intramuscular, subcutaneous ventral and subcutaneous dorsal) of the fat in the carcass.

CONCLUSION: The fatty acid profile that we observed in the fat of the Celta pigs does not differ greatly from those described by other authors in other autochthonous pig breeds. Principal component analysis offered a good separation of the mean samples according to the sex and location of fat of the pigs. Copyright © 2011 Society of Chemical Industry
Characterization of a multilayer film activated with Lactobacillus curvatus CRL705 bacteriocins
Authors: Blanco Massani Mariana , Morando Pedro J , Vignolo Graciela M , Eisenberg Patricia
Published: November 2011

BACKGROUND: Bacteriocins produced by lactic acid bacteria offer enormous promise for food safety preservation. In this study an active multilayer film obtained by the incorporation of lactocin 705 and lactocin AL705, two bacteriocins produced by Lactobacillus curvatus CRL705 with antimicrobial activity against Lactobacillus plantarum CRL691 and Listeria innocua 7, respectively, was characterized for its potential application in active packaging technology. Film activity performance at different storage conditions, bacteriocins transfer into water and sunflower oil, and film surface properties were evaluated.

RESULTS: Film activity against L. innocua 7 was maintained during 2, 4 and 6 weeks at 30, 10 and 5 °C respectively. At 30 and 10 °C, activity loss against L. plantarum CRL691 was observed on the second week of storage and after the fourth week at 5 °C. Results showed no significant difference for active multilayer film contact angle and seal properties compared to the control (without bacteriocins). A decrease in lactocin 705 inhibitory activity after sunflower oil contact was observed, while lactocin AL705 remained unaffected. After water contact, film activity was retained for both bacteriocins.

CONCLUSIONS: As demonstrated by antimicrobial activity and physico‐mechanical properties retention, lactocin 705 and AL705 active multilayer film present potential for application in active packaging technology. Copyright © 2011 Society of Chemical Industry
Perspectives to breed for improved baking quality wheat varieties adapted to organic growing conditions
Authors: Osman Aart M , Struik Paul C , Lammerts van Bueren Edith T
Published: November 2011

Northwestern European consumers like their bread to be voluminous and easy to chew. These attributes require a raw material that is rich in protein with, among other characteristics, a suitable ratio between gliadins and glutenins. Achieving this is a challenge for organic growers, because they lack cultivars that can realise high protein concentrations under the relatively low and variable availability of nitrogen during the grain‐filling phase common in organic farming. Relatively low protein content in wheat grains thus needs to be compensated by a high proportion of high‐quality protein. Organic farming therefore needs cultivars with genes encoding for optimal levels of glutenins and gliadins, a maximum ability for nitrogen uptake, a large storage capacity of nitrogen in the biomass, an adequate balance between vegetative and reproductive growth, a high nitrogen translocation efficiency for the vegetative parts into the grains during grain filling and an efficient conversion of nitrogen into high‐quality proteins. In this perspective paper the options to breed and grow such varieties are discussed. Copyright © 2011 Society of Chemical Industry
Polydimethylsiloxane‐functionalized monolithic silica column for reversed‐phase capillary liquid chromatography
Authors: Zhou Qiaoli , Zhang Pengfei , Jia Li
Published: November 2011

A polydimethylsiloxane (PDMS)‐modified monolithic silica column was prepared for performing reversed‐phase capillary liquid chromatography. The prepared PDMS column has a permeability of 6.4×10−14 m2 with a plate height <9.2 μm. Alkylbenzenes and polycyclic aromatic hydrocarbons (PAHs) were well separated with the PDMS stationary phase, which exhibited similar selectivity and separation mechanism to that of octadecyl stationary phase. The hydrophobic interactions between the analytes and the PDMS stationary phase mainly play the roles for the separation of alkylbenzenes and PAHs. The characteristics of the PDMS column for the separation of alkylbenzenes and PAHs demonstrated that it would be a promising alternative to the octadecyl column.
Reduced resolution transit delay prescan for quantitative continuous arterial spin labeling perfusion imaging
Authors: Dai Weiying , Robson Philip M , Shankaranarayanan Ajit , Alsop David C.
Published: November 2011

Arterial spin labeling perfusion MRI can suffer from artifacts and quantification errors when the time delay between labeling and arrival of labeled blood in the tissue is uncertain. This transit delay is particularly uncertain in broad clinical populations, where reduced or collateral flow may occur. Measurement of transit delay by acquisition of the arterial spin labeling signal at many different time delays typically extends the imaging time and degrades the sensitivity of the resulting perfusion images. Acquisition of transit delay maps at the same spatial resolution as perfusion images may not be necessary, however, because transit delay maps tend to contain little high spatial resolution information. Here, we propose the use of a reduced spatial resolution arterial spin labeling prescan for the rapid measurement of transit delay. Approaches to using the derived transit delay information to optimize and quantify higher resolution continuous arterial spin labeling perfusion images are described. Results in normal volunteers demonstrate heterogeneity of transit delay across different brain regions that lead to quantification errors without the transit maps and demonstrate the feasibility of this approach to perfusion and transit delay quantification. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Optically transmitted and inductively coupled electric reference to access in vivo concentrations for quantitative proton‐decoupled 13C magnetic resonance spectroscopy
Authors: Chen Xing , Pavan Matteo , Heinzer‐Schweizer Susanne , Boesiger Peter , Henning Anke
Published: November 2011

This report describes our efforts on quantification of tissue metabolite concentrations in mM by nuclear Overhauser enhanced and proton decoupled 13C magnetic resonance spectroscopy and the Electric Reference To access In vivo Concentrations (ERETIC) method. Previous work showed that a calibrated synthetic magnetic resonance spectroscopy‐like signal transmitted through an optical fiber and inductively coupled into a transmit/receive coil represents a reliable reference standard for in vivo 1H magnetic resonance spectroscopy quantification on a clinical platform. In this work, we introduce a related implementation that enables simultaneous proton decoupling and ERETIC‐based metabolite quantification and hence extends the applicability of the ERETIC method to nuclear Overhauser enhanced and proton decoupled in vivo 13C magnetic resonance spectroscopy. In addition, ERETIC signal stability under the influence of simultaneous proton decoupling is investigated. The proposed quantification method was cross‐validated against internal and external reference standards on human skeletal muscle. The ERETIC signal intensity stability was 100.65 ± 4.18% over 3 months including measurements with and without proton decoupling. Glycogen and unsaturated fatty acid concentrations measured with the ERETIC method were in excellent agreement with internal creatine and external phantom reference methods, showing a difference of 1.85 ± 1.21% for glycogen and 1.84 ± 1.00% for unsaturated fatty acid between ERETIC and creatine‐based quantification, whereas the deviations between external reference and creatine‐based quantification are 6.95 ± 9.52% and 3.19 ± 2.60%, respectively. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Reduced field of view MRI with rapid, B1‐robust outer volume suppression
Authors: Smith Travis B. , Nayak Krishna S.
Published: November 2011

MRI scans are inefficient when the size of the anatomy under investigation is small relative to the subject's full extent. The field of view must be expanded, and acquisition times accordingly prolonged. Shorter scans are feasible with reduced field of view imaging (rFOV) using outer volume suppression (OVS), a magnetization preparation sequence that attenuates signal outside a region of interest (ROI). This work presents a new OVS sequence with a cylindrical ROI, short duration, and improved tolerance for B inhomogeneity. The sequence consists of a nonselective adiabatic tipdown pulse, which provides B‐robust signal suppression, and a fast 2D spiral cylindrical tipback pulse. Analysis of the Bloch equations with transverse initial magnetization reveals a conjugate symmetric constraint for tipback pulses with small flip angles. This property is exploited to achieve two‐shot performance from the single‐shot tipback pulse. The OVS sequence is validated in phantoms and in vivo with multislice spiral imaging at 3 T. The relative signal‐to‐noise ratio efficiency of the proposed sequence was 98% in a phantom and 75–90% in vivo. The effectiveness is demonstrated with cardiovascular rFOV imaging, which exhibits improved resolution and reduced artifacts compared to conventional, full field of view imaging. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
In vivo three‐dimensional whole‐brain pulsed steady‐state chemical exchange saturation transfer at 7 T
Authors: Jones Craig K. , Polders Daniel , Hua Jun , Zhu He , Hoogduin Hans J. , Zhou Jinyuan , Luijten Peter , van Zijl Peter C.M.
Published: November 2011

Chemical exchange saturation transfer (CEST) is a technique to indirectly detect pools of exchangeable protons through the water signal. To increase its applicability to human studies, it is needed to develop sensitive pulse sequences for rapidly acquiring whole‐organ images while adhering to stringent amplifier duty cycle limitations and specific absorption rate restrictions. In addition, the interfering effects of direct water saturation and conventional magnetization transfer contrast complicate CEST quantification and need to be reduced as much as possible. It is shown that for protons exchanging with rates of less than 50–100 Hz, such as imaged in amide proton transfer experiments, these problems can be addressed by using a three‐dimensional steady state pulsed acquisition of limited B1 strength (∼1 μT). Such an approach exploits the fact that the direct water saturation width, magnetization transfer contrast magnitude, and specific absorption rate increase strongly with B1, while the size of the CEST effect for such protons depends minimally on B1. A short repetition time (65 ms) steady‐state sequence consisting of a brief saturation pulse (25 ms) and a segmented echo‐planar imaging train allowed acquisition of a three‐dimensional whole‐brain volume in approximately 11 s per saturation frequency, while remaining well within specific absorption rate and duty cycle limits. Magnetization transfer contrast was strongly reduced, but substantial saturation effects were found at frequencies upfield from water, which still confound the use of magnetization transfer asymmetry analysis. Fortunately, the limited width of the direct water saturation signal could be exploited to fit it with a Lorentzian function allowing CEST quantification. Amide proton transfer effects ranged between 1.5% and 2.5% in selected white and grey matter regions. This power and time‐efficient 3D pulsed CEST acquisition scheme should aid endogenous CEST quantification at both high and low fields. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Elastic fields in two joined transversely isotropic media of infinite extent as a result of rectangular loading
Authors: Xiao H. T. , Yue Z. Q.
Published: November 2011

This paper presents the closed‐form solutions for the elastic fields in two bonded rocks induced by rectangular loadings. Each of the two bonded rocks behaves as a transversely isotropic linear elastic solid of semi‐infinite extent. They are completely bonded together at a horizontal surface. The rectangular loadings are body forces along either vertical or horizontal directions and are uniformly applied on a rectangular area. The rectangular area is embedded in the two bonded rocks and is parallel to the horizontal interface. The classical integral transforms are used in the solution formulation, and the elastic solutions are expressed in the forms of elementary harmonic functions for the rectangular loadings. The stresses and displacements in the rocks induced by both the horizontal and vertical body forces are also presented. The numerical results illustrate the important effect of the anisotropic bimaterial properties on the stress and displacement fields. The solutions can be easily implemented for numerical calculations and applied to problems encountered in rock mechanics and engineering. Copyright © 2011 John Wiley & Sons, Ltd.
Chronic inhibition of endoplasmic reticulum stress and inflammation prevents ischaemia‐induced vascular pathology in type II diabetic mice
Authors: Amin Ali , Choi Soo‐kyoung , Galan Maria , Kassan Modar , Partyka Megan , Kadowitz Philip , Henrion Daniel , Trebak Mohamed , Belmadani Souad , Matrougui Khalid
Published: November 2011

Endoplasmic reticulum (ER) stress and inflammation are important mechanisms that underlie many of the serious consequences of type II diabetes. However, the role of ER stress and inflammation in impaired ischaemia‐induced neovascularization in type II diabetes is unknown. We studied ischaemia‐induced neovascularization in the hind‐limb of 4‐week‐old db − /db− mice and their controls treated with or without the ER stress inhibitor (tauroursodeoxycholic acid, TUDCA, 150 mg/kg per day) and interleukin‐1 receptor antagonist (anakinra, 0.5 µg/mouse per day) for 4 weeks. Blood pressure was similar in all groups of mice. Blood glucose, insulin levels, and body weight were reduced in db − /db− mice treated with TUDCA. Increased cholesterol and reduced adiponectin in db − /db− mice were restored by TUDCA and anakinra treatment. ER stress and inflammation in the ischaemic hind‐limb in db − /db− mice were attenuated by TUDCA and anakinra treatment. Ischaemia‐induced neovascularization and blood flow recovery were significantly reduced in db − /db− mice compared to control. Interestingly, neovascularization and blood flow recovery were restored in db − /db− mice treated with TUDCA or anakinra compared to non‐treated db − /db− mice. TUDCA and anakinra enhanced eNOS‐cGMP, VEGFR2, and reduced ERK1/2 MAP‐kinase signalling, while endothelial progenitor cell number was similar in all groups of mice. Our findings demonstrate that the inhibition of ER stress and inflammation prevents impaired ischaemia‐induced neovascularization in type II diabetic mice. Thus, ER stress and inflammation could be potential targets for a novel therapeutic approach to prevent impaired ischaemia‐induced vascular pathology in type II diabetes. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
How frequently are contraindicated or warned against combinations of drugs prescribed to patients receiving long‐term opioid therapy for chronic pain?
Authors: Richarz Ute , Jacobs Adam , Spina Edoardo
Published: November 2011

Purpose

To analyse the proportion of patients treated with an opioid for chronic pain who were prescribed concomitant medications that are warned against or contraindicated in the German summary of product characteristics to determine if warnings on drug–drug interactions (DDIs) are observed.

Methods

This retrospective analysis used longitudinal aggregated patient data from the Intercontinental Marketing Services Disease Analyzer in Germany. Patients with two or more prescriptions of morphine, hydromorphone, oxycodone or tramadol from 1 January 2006 to 31 December 2008 were included; drugs prescribed within 30 days of an opioid prescription were identified as concomitant medications. The frequency of concomitant treatment with drugs warned against or contraindicated in the German opioid summary of product characteristics was determined. Concomitant treatment with drugs metabolised by CYP3A4 inhibitors and inducers and CYP2D6 inhibitors was also considered.

Results

The Intercontinental Marketing Services database contained 13 405 eligible patients; 72% had concomitant diseases which may increase the risk for DDIs (hypertension, diabetes mellitus, renal failure, renal glomerular disease or renal tubulointerstitial disease). Very few patients received concomitant prescriptions of an opioid with a contraindicated drug. Many patients were prescribed opioids concomitantly with drugs with potential for harmful safety‐related DDIs or DDIs that alter the effectiveness of one or more of the opioids. A large proportion of all concomitant prescriptions with potential for DDIs were given to at‐risk patients aged 65 years and older.

Conclusions

Many patients that received an opioid for chronic pain were prescribed concomitant medications with the potential for safety‐related DDIs or interactions that would alter the effectiveness of the opioid. Copyright © 2011 John Wiley & Sons, Ltd.
Design principles for light trapping in thin silicon films with embedded dielectric nanoparticles
Authors: Nagel James R. , Scarpulla Michael A.
Published: November 2011

We investigate the light‐trapping effects of dielectric nanoparticles embedded within the active semiconductor layer of a thin‐film solar cell. The baseline model consists of a 1·0 µm slab of crystalline silicon on an aluminum back contact topped with a 75 nm Si3N4 anti‐reflective coating. Using finite‐difference time‐domain simulations, we calculate the absorption gain due to a periodic array of SiO2 nanospheres with characteristic depth, diameter, and pitch. Under optimal conditions, absorption gain due to embedded spheres can reach as high as 23·4% relative to the baseline geometry. Using Au‐core/SiO2‐shell nanoparticles, it is even possible to reach 30%. We then infer a series of design principles from our data that include trade‐offs between broadband scattering efficiency, poor absorption at long wavelengths, and semiconductor displacement. We also find that the optimal spacing between particles is approximately 400 nm. Above this distance, each scatterer acts in near isolation from any neighboring particles, and absorption gain is approximately linear with area coverage. Such gains are also expected for disordered as well as ordered arrays. These results demonstrate the potential of embedded dielectric nanoparticles as a tool for enhancing carrier generation in thin silicon solar cells. Copyright © 2011 John Wiley & Sons, Ltd.