bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐resolution separation of peptides by sodium dodecyl sulfate‐polyacrylamide gel “focusing”
Authors: Zilberstein Gleb , Korol Leonid , Shlar Ilya , Righetti Pier Giorgio , Bukshpan Shmuel 
Published: April 2008

AbstractAs a follow‐up of our previous report (Anal. Chem. 2007, 79, 821–827) on analytical SDS‐PAGE focusing, a refinement of the method for separation of peptides in the small to medium Mr range (0.5–10 kDa) is here reported, based on a shallow gradient of immobilized positive charges (0–10 mM) onto a minimally sieving polyacrylamide gel matrix (4%T, 2.5%C). Unlike conventional SDS‐PAGE, which rarely can achieve the separations of polypeptide chains below a critical value of 10 kDa, the present method can be fine‐tuned to perform such separations even down to a size of only 500 Da. In the case of larger fragments, the major peptide zones are shown, under microscope observation, to be composed by envelops of bands as narrow as 20–100 μm, spaced at regular intervals of 100–150 μm. It is hypothesized that such larger peptides could form complexes with rather small SDS micelles and that such peptide–SDS complexes could differ in charge by just a single negative charge.
Four New Neoclerodane Diterpenoids from Ajuga decumbens
Authors: Huang Xiao‐Chun , Qin Song , Guo Yue‐Wei , Krohn Karsten 
Published: April 2008

AbstractFour new neoclerodane diterpenoids, 15‐epilupulin A (1), 6‐O‐deacetylajugamarin (2), and ajugadecumbenins A (3) and B (4), were isolated from the whole plants of Ajuga decumbens. Their structures were elucidated on the basis of spectroscopic data and chemical correlations.
Iridoid Glycosides from Gardenia jasminoidesEllis
Authors: Fu Xiao‐Mei , Chou Gui‐Xin , Wang Zheng‐Tao 
Published: April 2008

AbstractThree new iridoid glycosides, 4″‐O‐[(E)‐p‐coumaroyl]gentiobiosylgenipin (1), 6′‐O‐[(E)‐caffeoyl]deacetylasperulosidic acid methyl ester (2), and 6′‐O‐[(E)‐sinapoyl]gardoside (3), together with seven analogues, 4–10, were isolated from the BuOH extract of the fruits of Gardenia jasminoides Ellis. Their structures were determined by means of spectroscopic analyses, including HR‐ESI‐MS, IR, and 1H‐ and 13C‐NMR, and 2D experiments (COSY, HSQC, and HMBC), and comparison with known related compounds.
Ring Opening of 2‐(Benzylamino)‐2H‐1,4‐benzoxazin‐3(4H)‐ones and 2‐Bromo‐2H‐1,4‐benzoxazin‐3(4H)‐ones
Authors: Ilaš Janez , Kikelj Danijel 
Published: April 2008

AbstractSubstituted 2‐(benzylamino)‐2H‐1,4‐benzoxazin‐3(4H)‐ones are unstable under alkaline and acidic conditions, undergoing opening of the benzoxazinone ring. 2‐Bromo‐2H‐1,4‐benzoxazin‐3(4H)‐ones show similar degradation under alkaline conditions, while replacement of Br at C(2) to give 2‐hydroxy‐2H‐1,4‐benzoxazin‐3(4H)‐ones was observed only under mild alkaline conditions. Mechanisms of ring opening and degradation to 2‐aminophenol derivatives are proposed.
Modified Cyclodextrins as Enantioselective Hosts for Amino Acids
Authors: Kumar Vydyula Pavan , Suryanarayana Iragavarapu , Nageswar Yadavalli Venkata Durga , Rao Kakulapati Rama 
Published: April 2008

AbstractTwo modified β‐cyclodextrins, H‐2 and H‐3, having a flexible appended moiety were studied for the chiral discrimination of the enantiomers of various amino acids by means of fluorescence as signaling option. These hosts quenched the fluorescence intensities of amino acids upon binding. The d‐enantiomers were better recognized by these hosts. The association constants (Ks) and enantioselectivity factors (α) of the host⋅guest complexes were calculated.
A New Diterpenoid and a New Diterpenoid Alkaloid from Aconitum coreanum
Authors: Yang Chun‐Hua , Wang Xia‐Chang , Tang Qing‐Fa , Liu Wen‐Ying , Liu Jing‐Han 
Published: April 2008

AbstractA new diterpenoid, guan fu diterpenoid A (1), and a new diterpenoid alkaloid, guan fu base S (2), were isolated from the Chinese medicinal herb Aconitum coreanum (Lèvl.) Rapaics, together with five known diterpenoid alkaloids guan fu base P, guan fu base R, guan fu base G, guan fu base F, and guan fu base Z. The structures of the two new compounds were elucidated as ent‐kaurane‐16,20‐diol (1) and (11β,13S)‐2,3,15,16‐tetradehydro‐16,17‐dihydrohetisan‐11,13,14‐triol 11,13‐diacetate (2) on the basis of HR‐MS and 2D‐NMR analyses. This is the first report of an ent‐kaurane diterpenoid in Aconitum coreanum.
Flash Vacuum Thermolysis of 4H‐3,1‐Benzoxathiin‐4‐thione: UV‐Photoelectron Spectroscopy Characterization and Quantum Chemistry Studies
Authors: Drewnowski Tomasz , Chrostowska Anna , Leśniak Stanisław , Dargelos Alain , Khayar Saïd 
Published: April 2008

AbstractThe mechanism of the reaction of 4H‐3,1‐benzoxathiin‐4‐thione (3) under flash vacuum thermolysis conditions has been studied by UV‐photoelectron spectra. It was shown that in the first step of the reaction at 400° 3 underwent the Schönberg–Newman–Kwart rearrangement to give 4H‐1,3‐benzodithiin‐4‐one (6). Increasing of the temperature to 650° resulted in the elimination of thioformaldehyde and the formation of benzothiet‐2‐one (1). Subsequent elevation of the temperature prompted presumably the ring opening of 1 to (6‐thioxocyclohexa‐2,4‐dien‐1‐ylidene)methanone (7) (at 680°), which at 700° eliminated CO and underwent a Wolff‐type ring contraction to give (cyclopenta‐2,4‐dien‐1‐ylidene)methanethione (2). UV‐Photoelectron spectra were recorded at different steps of the reaction and analyzed considering the theoretical evaluation of ionization potentials.
Improvement in B1‐inhomogeneity artifacts in the abdomen at 3T MR imaging using a radiofrequency cushion
Authors: Franklin Kendra M. , Dale Brian M. , Merkle Elmar M. 
Published: April 2008

AbstractPurposeTo determine the impact of a radiofrequency (RF) cushion on abdominal image quality at 3T.Materials and MethodsTwenty volunteers were scanned on a 3T system with and without the use of an RF cushion. T2‐weighted HASTE and true‐FISP sequences were used for coronal imaging, and each sequence was performed with and without integrated parallel acquisition techniques (iPAT). Additionally, axial T2‐weighted HASTE and true‐FISP imaging without iPAT was performed. The effect on image quality was assessed by subjectively evaluating the presence and severity of RF inhomogeneity artifacts by two independent readers in a side‐by‐side comparison with a 5‐point differential receiver operating characteristics curve.ResultsBoth readers considered the quality of HASTE images acquired with the RF cushion to be significantly better in all cases. The quality of true‐FISP images did not benefit significantly from the use of the RF cushion in any case.ConclusionThe RF cushion significantly improves image quality for abdominal imaging at 3T by reducing or eliminating B1‐inhomogenity artifacts. This improved image quality is seen on turbo spin echo‐based T2‐weighted imaging such as HASTE but does not apply to gradient echo‐based T2‐weighted imaging such as the true‐FISP sequence. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
Computer‐assisted identification of the central sulcus in patients with brain tumors using MRI
Authors: Uwano Ikuko , Kameda Masashi , Inoue Takashi , Nishimoto Hideaki , Fujiwara Shunrou , Hirooka Ryonoshin , Ogawa Akira 
Published: April 2008

AbstractPurposeTo develop computer‐assisted image processing to identify the central sulcus from the MRI data sets in patients with brain tumors.Materials and MethodsAll MR images were acquired with a 3.0 Tesla scanner by three‐dimensional (3D) spoiled gradient recalled acquisition using the steady state (SPGR) gradient‐echo sequence and short inversion time inversion‐recovery fast spin‐echo sequence. The sulci were extracted automatically from reconstructed two‐dimensional images of the cortical surface of 30 patients with brain tumors, and the extracted sulci were scored according to matching of the accepted anatomical features of the central sulcus. The candidates with the three highest scores were then superimposed on the 3D images. The correct position of the central sulcus was agreed by two senior neurosurgeons and one neuroradiologist.ResultsOne of the three candidates corresponded to the central sulcus identified by the manual segmentation method for all 60 affected and unaffected hemispheres in the 30 patients. The candidate with the highest score coincided with the central sulcus in 26 of the 28 unaffected hemispheres and in 28 of the 32 affected hemispheres.ConclusionThe proposed method of computer‐assisted image processing can provide accurate guidance to identifying the central sulcus in patients with brain tumors. J. Magn. Reson. Imaging 2008. © 2008 Wiley‐Liss, Inc.
Antioxidant activity of the ethanolic extract from the bark ofChamaecyparis obtusavar.formosana
Authors: Marimuthu Palanisamy , Wu Chi‐Lin , Chang Hui‐Ting , Chang Shang‐Tzen 
Published: April 2008

AbstractBACKGROUND:Chamaecyparis obtusavar.formosana(Taiwan hinoki) is an endemic conifer in Taiwan and the purpose of this study is to evaluate the antioxidant activity of various fractions obtained from the bark of this plant material. The ethanolic extract of the bark was sequentially separated into three fractions, includingn‐hexane, ethyl acetate and ethanol soluble fractions, by liquid–liquid partition. Then the antioxidant activities of crude extract and three fractions along with 13 subfractions obtained from the ethyl acetate (EA) soluble fraction were tested for several antioxidant assays.RESULTS:The total phenolic content of the samples varied from 27.71 to 102.86 mg GAE g−1dry weight for fractions, and from 49.94 to 206.46 mg GAE g−1for subfractions (where GAE is milligrams of gallic acid per gram of extract). The Trolox equivalent antioxidant capacity (TEAC) ranged from 0.15 to 0.26 mmol L−1Trolox equivalents. The EA soluble fraction was found to be the best antioxidant‐rich fraction in terms of DPPH and reducing power assays. With further data analysis it was found that there was a positive correlation between the total phenolic content of extracts and TEAC isR2= 0.61.CONCLUSION:Results from various antioxidant assays showed that the EA fraction possessed strong antioxidant activity. This would provide additional information about the antioxidant activity of bark extract of this plant species. Copyright © 2008 Society of Chemical Industry
Effects of nitrogen application on malt modification and dimethyl sulfide precursor production in two Japanese barley cultivars
Authors: Nanamori Masahito , Kanatani Ryoichi , Kihara Makoto , Kawahara Kazumitsu , Hayashi Katsuhiro , Watanabe Toshihiro , Shinano Takuro , Osaki Mitsuru 
Published: April 2008

AbstractBACKGROUND: Nitrogenous components have a great influence on both malt and beer qualities. Barley storage proteins are degraded during the germination process, in which amino acids and small peptides are released. Some of these compounds relate to dimethyl sulfide precursor production in the malting process. In this study, barley and malt qualities were investigated using two Japanese barley cultivars, Sukai Golden and Mikamo Golden, with several different nitrogen (N) treatments.RESULTS: Nitrogen top‐dressing treatments efficiently increased N and sulfur (S) concentrations in grains. A difference in malt modification was induced by these treatments without any change in protease activity in malts. S‐Methyl methionine (SMM) concentration in malt of Sukai Golden with low‐N treatment was 1.8–2.1 times higher than that with higher‐N treatments. Methionine concentration in malts was not significantly affected by N treatments of both cultivars, while grain S level was not consistent under any treatments.CONCLUSION: Results show that low‐N treatment increases SMM concentration in malts despite major S‐containing amino acids of malts being not highly affected by the difference in nutrient status of grains. Further investigations are necessary into aspects of both metabolic profiles in barley germination and SMM degradation in the kilning process. Copyright © 2008 Society of Chemical Industry
Stakeholder perspectives on the European Union tourism policy framework and their preferences on the type of involvement
Authors: Anastasiadou Constantia 
Published: April 2008

AbstractDespite a growing body of literature on regional trading agreements and tourism, little empirical evidence exists on how tourism policy is formulated at the supranational level. The study focuses on the European Union and employs stakeholder interviews to construct the institutional environment for tourism and to identify potential areas for involvement in tourism. Four different approaches are identified ranging from maintaining the status quo to a common tourism policy. It is concluded that because of the complexities of the institutional environment for tourism and the diversity of opinion among stakeholders, a significant change in the status quo is unlikely to happen. Copyright © 2008 John Wiley & Sons, Ltd.
Cruising, freighter‐style: a phenomenological exploration of tourist recollections of a passenger freighter travel experience
Authors: Szarycz Gregory S. 
Published: April 2008

AbstractOpportunities to participate in freighter cruises, which use cargo ships outfitted with a small number of passenger cabins, have been growing in recent years. In order to better understand the experiential characteristics of this phenomenon, 22 respondents were selected to take part in a phenomenological study based on their recollections of the activity. The respondents discussed the issues of remoteness and the often limited tourism facilities they were able to access during their travels. Mostly though, they reflected on friendships made, opportunities for learning and places visited as being an important and enjoyable part of the freighter cruise experience. Copyright © 2008 John Wiley & Sons, Ltd.
Elastohydrodynamic study of vegetable oil–polyalphaolefin blends
Authors: Bantchev Grigor , Biresaw Girma 
Published: April 2008

AbstractTwo polyalphaolefins, of higher and lower viscosity than vegetable oils, were used to make binary blends of varying compositions with soy bean and canola oils. The pure oils and the blends were used in viscosity and film thickness investigations. The effects of composition and temperature on viscosity were found to agree well with the theoretical predictions of a simple mixing law. The film thicknesses of the various blends under elastohydrodynamic conditions were measured at 20 N load, and varying entrainment speeds and temperatures. From the data, pressure–viscosity coefficients, α, as a function composition and temperature were obtained. The resulting α values were compared with theoretical predictions. Experimental values of α as a function of composition showed a slight negative or no deviation from the values predicted by an ideal mixing model. On the other hand, experimental values of α displayed a mild decrease with increasing temperature, while the model predicted a sharp decrease with increasing temperature. Published in 2008 by John Wiley & Sons, Ltd.
Analysis of the Influence of Processing Conditions on the Supramolecular Structure and Antioxidant Distribution in PP‐Pipes Using Infrared Microscopy
Authors: Brüll Robert , Geertz Guru , Kothe Hans , Macko Tibor , Rudschuck Michael , Wenzel Mirko , Engelsing Kurt , Wüst Jürgen , Bastian Martin 
Published: April 2008

AbstractThe supramolecular structure in pipe walls of isotactic PP‐R is a function of compound composition and processing parameters, which both influence the mechanical properties of the pipes. µFTIR shows a gradient of the crystallinity across the pipe wall, with a lower‐crystalline outer layer, and a higher‐crystalline core layer. The rate of extrusion has an influence on the thickness of the outer layer. The nucleating effect on the morphological profile throughout the pipe wall can be visualised. µFTIR shows a homogeneous distribution of the primary antioxidant in the pipe wall. Both the spectral crystallinity and the antioxidant concentration distribution are calculated.magnified image
Polynomial stability without polynomial decay of the relaxation function
Authors: Tatar Nasser‐eddine 
Published: April 2008

AbstractWe consider a linear viscoelastic problem and prove polynomial asymptotic stability of the steady state. This work improves previous works where it is proved that polynomial decay of solutions to the equilibrium state occurs provided that the relaxation function itself is polynomially decaying to zero. In this paper we will not assume any decay rate of the relaxation function. In case the kernel has someflatzones then we prove polynomial decay of solutions provided that these flat zones are nottoo big. If the kernel is strictly decreasing then there is no need for this assumption. Copyright © 2008 John Wiley & Sons, Ltd.
Fast mapping of myocardial blood flow with MR first‐pass perfusion imaging
Authors: Goldstein Thomas A. , Jerosch‐Herold Michael , Misselwitz Bernd , Zhang Haosen , Gropler Robert J. , Zheng Jie 
Published: April 2008

AbstractAccurate and fast quantification of myocardial blood flow (MBF) with MR first‐pass perfusion imaging techniques on a pixel‐by‐pixel basis remains difficult due to relatively long calculation times and noise‐sensitive algorithms. In this study, Zierler's central volume principle was used to develop an algorithm for the calculation of MBF with few assumptions on the shapes of residue curves. Simulation was performed to evaluate the accuracy of this algorithm in the determination of MBF. To examine our algorithm in vivo, studies were performed in nine normal dogs. Two first‐pass perfusion imaging sessions were performed with the administration of the intravascular contrast agent Gadomer at rest and during dipyridamole‐induced vasodilation. Radiolabeled microspheres were injected to measure MBF at the same time. MBF measurements in dogs using MR methods correlated well with the microsphere measurements (R2 = 0.96, slope = 0.9), demonstrating a fair accuracy in the perfusion measurements at rest and during the vasodilation stress. In addition to its accuracy, this method can also be optimized to run relatively fast, providing potential for fast and accurate myocardial perfusion mapping in a clinical setting. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Full‐brain coverage and high‐resolution imaging capabilities of passband b‐SSFP fMRI at 3T
Authors: Lee Jin Hyung , Dumoulin Serge O. , Saritas Emine U. , Glover Gary H. , Wandell Brian A. , Nishimura Dwight G. , Pauly John M. 
Published: April 2008

AbstractPassband balanced‐steady‐state free precession (b‐SSFP) fMRI is a recently developed method that utilizes the passband (flat portion) of the b‐SSFP off‐resonance response to measure MR signal changes elicited by changes in tissue oxygenation following increases in neuronal activity. Rapid refocusing and short readout durations of b‐SSFP, combined with the relatively large flat portion of the b‐SSFP off‐resonance spectrum allows distortion‐free full‐brain coverage with only two acquisitions. This allows for high‐resolution functional imaging, without the spatial distortion frequently encountered in conventional high‐resolution functional images. Finally, the 3D imaging compatibility of the b‐SSFP acquisitions permits isotropic‐voxel‐size high‐resolution acquisitions. In this study we address some of the major technical issues involved in obtaining passband b‐SSFP‐based functional brain images with practical imaging parameters and demonstrate the advantages through breath‐holding and visual field mapping experiments. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
Local excitation black blood imaging at 3T: Application to the carotid artery wall
Authors: Bornstedt Axel , Bernhardt Peter , Hombach Vinzenz , Kamenz Joachim , Spiess Jochen , Subgang Anne , Rasche Volker 
Published: April 2008

AbstractA novel approach for imaging large sections of the carotid artery wall at isotropic spatial resolution is presented. Local excitation by means of 2D excitation pulses was combined with a diffusion‐prepared segmented steady‐state black‐blood gradient echo technique enabling the assessment of the carotid arterial wall over a range of up to 15 cm. The carotid arteries of five healthy volunteers were imaged with the proposed technique. Signal‐to‐noise ratio (SNR), wall‐lumen contrast‐to‐noise ratio (CNR), and vessel dimensions were assessed and compared to conventional excitation techniques. In all experiments black‐blood contrast could be realized over the covered carotid arteries with similar SNR and CNR as the conventional technique covering the region of the bulbus only. The proposed technique enables the time‐efficient coverage of the carotid arteries without compromising wall‐lumen CNR and geometrical accuracy. Furthermore, the proposed technique appears to be less sensitive to motion and swallowing artifacts due to the local character of the excitation. Magn Reson Med, 2008. © 2008 Wiley‐Liss, Inc.
ℋ︁2 suboptimal estimation and control for nonnegative dynamical systems
Authors: Haddad Wassim M. , Chellaboina Vijaysekhar , Gholami Behnood 
Published: April 2008

AbstractLinear matrix inequalities (LMIs) provide a powerful design framework for linear control problems. In this paper, we use LMIs to develop ℋ︁2 (sub)optimal estimators and controllers for nonnegative dynamical systems. Specifically, we formulate a series of generalized eigenvalue problems subject to a set of LMI constraints for designing ℋ︁2 suboptimal estimators, static controllers, and dynamic controllers for nonnegative dynamical systems. The resulting ℋ︁2 suboptimal controllers guarantee that the closed‐loop plant system states remain in the nonnegative orthant of the state space. Finally, a numerical example is provided to demonstrate the efficacy of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd.
Genomic and immunophenotypical characterization of pure micropapillary carcinomas of the breast
Authors: Marchiò C , Iravani M , Natrajan R , Lambros MB , Savage K , Tamber N , Fenwick K , Mackay A , Senetta R , Palma S Di , Schmitt FC , Bussolati G , Ellis IO , Ashworth A , Sapino A , Reis‐Filho JS 
Published: April 2008

AbstractPure invasive micropapillary carcinoma (MPC) is a special histological type that accounts for 0.7–3% of all breast cancers. MPC has a distinctive growth pattern and a more aggressive clinical behaviour than invasive ductal carcinomas of no special type (IDC‐NSTs). To define the molecular characteristics of MPCs, we profiled a series of 12 MPCs and 24 grade and oestrogen receptor (ER)‐matched IDC‐NSTs using high‐resolution microarray comparative genomic hybridization (aCGH). In addition, we generated a tissue microarray containing a series of 24 MPCs and performed immunohistochemical analysis with ER, PR, Ki‐67, HER2, CK5/6, CK14, CK17, EGFR, topoisomerase‐IIα, cyclin D1, caveolin‐1, E‐cadherin, and β‐catenin antibodies. In situ hybridization probes were employed to evaluate the prevalence of amplification of HER2, TOP2A, EGFR, CCND1, MYC, ESR1, and FGFR1 genes. aCGH analysis demonstrated that MPCs significantly differed from IDC‐NSTs at the genomic level. Gains of 1q, 2q, 4p, 6p, 6q23.2–q27, 7p, 7q, 8p, 8q, 9p, 10p, 11q, 12p, 12q, 16p, 17p, 17q, 19p, 20p, 20q, and 21q, and losses of 1p, 2p, 6q11.1–q16.3, 6q21–q22.1, 9p, 11p, 15q, and 19q were more prevalent in MPCs. High‐level gains/amplifications of 8p12–p11, 8q12, 8q13, 8q21, 8q23, 8q24, 17q21, 17q23, and 20q13 were significantly associated with MPCs. A comparison between 24 MPCs and a series of 48 grade and ER‐matched IDC‐NSTs revealed that high cyclin D1 expression, high proliferation rates, and MYC (8q24) amplification were significantly associated with MPCs. Our results demonstrate that MPCs have distinct histological features and molecular genetic profiles supporting the contention that they constitute a distinct pathological entity. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.