bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of activity and selectivity in lipase‐catalyzed transesterification in ionic liquids by the use of additives
Authors: Hernández‐Fernández Francisco J , de los Ríos Antonia P , Rubio Manuel , Gómez Demetrio , Víllora Gloria 
Published: September 2007

AbstractBACKGROUND: Seven ionic liquids (ILs) based on 1‐alkyl‐3‐methylimidazolium cation in combination with hexafluorophosphate and bis{(trifluoromethyl)sulfonyl}imide anions were tested as reaction media for lipase‐catalyzed transesterification in low water conditions. With the aim of improving the activity and/or selectivity of the lipase, various treatments were applied to ionic liquid media such as equilibration with aqueous solutions of salts, NaHCO3 or Na2CO3, or the addition of a catalytic amount of a non‐reactive organic base to the reaction mixture, triethylamine.RESULTS: The treated ionic liquids were shown to be excellent media for lipase‐catalyzed ester synthesis by transesterification compared with conventional organic solvents, such as n‐hexane. All treatments were found to enhance the synthetic activity of the enzyme, the best results being achieved with the addition of triethylamine. The addition of a catalytic amount of this base to the ILs resulted in a significant increase in both the synthetic activity and selectivity values. For instance, the synthetic activity in [emim+][TfN2−] was enhanced more than 12 times and the selectivity increased from 86% to 95% when triethylamine was used.CONCLUSION: These treatments could be easy‐to‐use approaches to improve the efficiency of enzymatic reactions in ionic liquids when the reaction does not proceed smoothly. Copyright © 2007 Society of Chemical Industry
Fish fingers: digit homologues in sarcopterygian fish fins
Authors: Johanson Zerina , Joss Jean , Boisvert Catherine A. , Ericsson Rolf , Sutija Margareta , Ahlberg Per E. 
Published: September 2007

AbstractA defining feature of tetrapod evolutionary origins is the transition from fish fins to tetrapod limbs. A major change during this transition is the appearance of the autopod (hands, feet), which comprises two distinct regions, the wrist/ankle and the digits. When the autopod first appeared in Late Devonian fossil tetrapods, it was incomplete: digits evolved before the full complement of wrist/ankle bones. Early tetrapod wrists/ankles, including those with a full complement of bones, also show a sharp pattern discontinuity between proximal elements and distal elements. This suggests the presence of a discontinuity in the proximal‐distal sequence of development. Such a discontinuity occurs in living urodeles, where digits form before completion of the wrist/ankle, implying developmental independence of the digits from wrist/ankle elements. We have observed comparable independent development of pectoral fin radials in the lungfish Neoceratodus (Osteichthyes: Sarcopterygii), relative to homologues of the tetrapod limb and proximal wrist elements in the main fin axis. Moreover, in the Neoceratodus fin, expression of Hoxd13 closely matches late expression patterns observed in the tetrapod autopod. This evidence suggests that Neoceratodus fin radials and tetrapod digits may be patterned by shared mechanisms distinct from those patterning the proximal fin/limb elements, and in that sense are homologous. The presence of independently developing radials in the distal part of the pectoral (and pelvic) fin may be a general feature of the Sarcopterygii. J. Exp. Zool. (Mol. Dev. Evol.) 308B:757–768, 2007. © 2007 Wiley‐Liss, Inc.
Hamilton cycles in prisms
Authors: Kaiser Tomáš , Ryjáček Zdeněk , Král Daniel , Rosenfeld Moshe , Voss Heinz‐Jürgen 
Published: September 2007

AbstractThe prism over a graph G is the Cartesian product G □ K2 of G with the complete graph K2. If G is hamiltonian, then G□K2 is also hamiltonian but the converse does not hold in general. Having a hamiltonian prism is shown to be an interesting relaxation of being hamiltonian. In this article, we examine classical problems on hamiltonicity of graphs in the context of having a hamiltonian prism. © 2007 Wiley Periodicals, Inc. J Graph Theory 56: 249–269, 2007
Constructing trees in graphs with no K2,s
Authors: Balasubramanian Suman , Dobson Edward 
Published: September 2007

AbstractLet s ≥ 2 be an integer and k > 12(s − 1) an integer. We give a necessary and sufficient condition for a graph G containing no K2,s with $\delta(G)\ge{k}/2$ and $\Delta(G)\ge k$ to contain every tree T of order k + 1. We then show that every graph G with no K2,s and average degree greater than k − 1 satisfies this condition, improving a result of Haxell, and verifying a special case of the Erdős—Sós conjecture, which states that every graph of average degree greater than k − 1 contains every tree of order k + 1. © 2007 Wiley Periodicals, Inc. J Graph Theory 56: 301–310, 2007
N‐2‐(4‐N‐(4‐[18F]Fluorobenzamido)phenyl)‐propyl‐2‐propanesulphonamide: synthesis and radiofluorination of a putative AMPA receptor ligand
Authors: Kronenberg Ute B. , Drewes Birte , Sihver Wiebke , Coenen Heinz H. 
Published: September 2007

AbstractArylpropylsulphonamides are in the focus of research asα‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolpropionic acid (AMPA) receptor ligands. A new fluorine‐18‐labelled potentiator of AMPA receptors was synthesized as a potential radiotracer for cerebral imaging with positron emission tomography. UsingN‐2‐(4‐N‐(4‐nitrobenzamido)phenyl)‐propyl‐2‐propanesulphonamide (7) as labelling precursor for a Kryptofix 2.2.2®/K2CO3‐activated nucleophilic radiofluorination, the putative AMPA receptor ligandN‐2‐(4‐N‐(4‐[18F]fluorobenzamido)phenyl)‐propyl‐2‐propanesulphonamide [18F]8was obtained in one step. Optimization of the reaction parameters time, temperature, solvent and concentration gave a radiochemical yield of 38±8% at 180°C in dimethylsulphoxide within 30‐min reaction time. After a solid‐phase extraction followed by a high‐performance liquid chromatography separation, the product could be obtained in radiochemical yields of 5±1.5%. Radiochemical purity was higher than 95% and the specific activity amounted to 77±40 GBq/µmol. Firstin vitroassays with rat brain slices revealed a high non‐specific binding and a uniform distribution of [18F]8not lending it forin vivoimaging purposes. Copyright © 2007 John Wiley & Sons, Ltd.
Effects of partial substitution of concentrates with maize silage in organic dairy cow rations on performance and feed efficiency
Authors: Velik Margit , Baumung Roswitha , Zollitsch Werner , Knaus Wilhelm F. 
Published: September 2007

AbstractBACKGROUND: The general goal of organic dairy farming is to minimize purchased concentrate use and focus on milk production from forages. The aim of the present paper is to examine the influence of a partial substitution of purchased concentrates with home‐grown maize silage on feed intake, milk production and feed efficiency in rations for organic dairy cows. In the experimental treatment group (E), two‐thirds of average herd concentrate intake was replaced with 2.7 kg maize silage on a dry matter (DM) basis.RESULTS: In treatment E, total DM, energy and protein intake were significantly reduced compared to the control treatment group (C). Daily milk yield decreased in E by 11% and milk urea content was significantly lower. Calculated milk production from forage was significantly higher (91 versus 71%) in treatment E. Efficiency of dietary nitrogen (N) utilization (calculated as milk N as a percentage of N intake) was slightly improved in E and protein and energy balance (calculated as intake as a percentage of requirements) were closer to zero than in C.CONCLUSION: The present study indicates a potential to reduce levels of concentrates and substitute them with maize silage in organic dairy cow rations at least in the second half of lactation. Copyright © 2007 Society of Chemical Industry
Anthocyanins and other polyphenolics in American elderberry (Sambucus canadensis) and European elderberry (S. nigra) cultivars
Authors: Lee Jungmin , Finn Chad E. 
Published: September 2007

AbstractBACKGROUND: Ten genotypes representing two elderberry species, Sambucus canadensis L. (eight genotypes) and S. nigra L. (two genotypes), were examined for their anthocyanins (ACY), total phenolics (TP),°Brix, titratable acidity (TA), and pH over two growing seasons.RESULTS: Overall, fruit generally had higher ACY, TP, ACY/TP,°Brix, and pH in 2005 than 2004. All samples of S. canadensis had similar anthocyanin profiles to one another, but were distinctly different from S. nigra. Both species had cyanidin‐based anthocyanins as major pigments. Previously unreported anthocyanins were identified in some samples in this study. Trace levels of delphinidin 3‐rutinoside were present in all elderberry samples except cv. ‘Korsør’. Also, petunidin 3‐rutinoside was detected in cvs ‘Adams 2’, ‘Johns’, ‘Scotia’, ‘York’, and ‘Netzer’ (S. canadensis). The identified polyphenolics of both species were mainly composed of cinnamic acids and flavonol glycosides. The major polyphenolic compounds present in S. canadensis were neochlorogenic acid, chlorogenic acid, rutin, and isorhamnetin 3‐rutinoside, while chlorogenic acid and rutin were found to be major polyphenolic compounds in S. nigra.CONCLUSION: Sufficient variability was seen among these genotypes to suggest that a successful breeding program could be carried out to improve levels of the various compounds evaluated in this study. Copyright © 2007 Society of Chemical Industry
In vitro degradation of forage chicory (Cichorium intybus L.) by endopoly‐ galacturonase
Authors: Sun Xuezhao , Hoskin Simone O , Andrew Ian G , Joblin Keith N , Harris Philip J 
Published: September 2007

AbstractBACKGROUND: Leaves of forage chicory break down rapidly in the rumen despite little or no rumination. Because chicory cell walls contain high concentrations of pectin, degradation of leaf midrib and leaf lamina tissues by pectinolytic enzymes was investigated.RESULTS: Treatment with endopolygalacturonase (endo‐PG) degraded fresh intact chicory leaves to particles of less than 1 mm in length and solubilised more than 70% of the dry matter within 16 h. Uronic acids were released more extensively than neutral monosaccharides. In similar treatments, 77% of white clover leaflets and 12% of perennial ryegrass leaf blades were solubilised or broken down to particles with a size of less than 1 mm. The degradation of pectic polysaccharides in chicory midribs was monitored by immunofluorescence labelling with monoclonal antibodies JIM5 and JIM7 which target partially methyl‐esterified epitopes of the homogalacturonan (HG) domain of pectin. Examination by fluorescence microscopy revealed that cell separation in the cortical parenchyma of chicory midrib following endo‐PG treatment was associated with loss of HG from the middle lamella, the corners of intercellular spaces and from the tricellular junctions.CONCLUSION: The results of the current study suggest that one of the main contributions to chicory breakdown in the rumen may be cell separation caused by degradation of HG by pectinolytic enzymes from rumen bacteria. Copyright © 2007 Society of Chemical Industry
Effect of fruit ripeness and method of fruit drying on the extractability of avocado oil with hexane and supercritical carbon dioxide
Authors: Mostert Mathilda E , Botha Ben M , Plessis Lourens M Du , Duodu Kwaku G 
Published: September 2007

AbstractBACKGROUND: Oil yield from avocado fruit may be influenced by fruit pre‐treatment and extraction method. Unripe and ripe avocado fruit pieces were deep‐frozen at − 20 °C and either freeze‐dried or oven‐dried (80 °C). Oil yield from these samples was determined after extraction with hexane and supercritical carbon dioxide (SC‐CO2). The fruit samples were examined using scanning electron microscopy before and after oil extraction.RESULTS: Average oil yield from ripe fruit (freeze‐dried and oven‐dried combined) was 72 g kg−1 higher than from unripe fruit for SC‐CO2 extracts and 61 g kg−1 higher for hexane extracts. This may be due to enzymatic degradation of parenchyma cell walls during ripening, thus making the oil more available for extraction. Freeze‐dried samples had a mean oil yield 55 g kg−1 greater than oven‐dried samples for SC‐CO2 extracts and 31 g kg−1 higher for hexane extracts. However, oil yields from ripe fruit (freeze‐dried and oven‐dried) subjected to hexane extraction were not significantly different. All hexane extracts combined had a mean oil yield 93 g kg−1 higher than SC‐CO2 extracts.CONCLUSION: SC‐CO2 may be more selective and may create paths of least resistance through the plant material. Hexane, on the other hand, is less selective and permeates the whole plant material, leading to more complete extraction and higher oil yields under the experimental conditions. Copyright © 2007 Society of Chemical Industry
Potential health benefits of conjugated trienoic acids
Authors: Koba Kazunori , Belury Martha A. , Sugano Michihiro 
Published: September 2007

AbstractCurrent studies on physiological functions of certain plant seed oils containing conjugated trienoic acids as a major fatty acid component are indicative of the possible usefulness of these oils as a new type of functional oils. Here, we describe the potential health benefits of conjugated trienoic acids.
Surface Structural Investigation of Starch‐Based Biomaterials
Authors: Pashkuleva Iva , Azevedo Helena S. , Reis Rui L. 
Published: September 2007

AbstractSurface structural characterisation of three different starch‐based blends (with poly[ethylene‐co‐(vinyl alcohol)], cellulose acetate and polycaprolactone) was carried out. The results show that there is a difference between the bulk and the surface composition of all studied blends. Two different hypotheses were investigated – predominant presence of a synthetic component on the surface and possible inter‐ and/or intramolecular bonds. The results were related to previous data for cell behaviour on those materials. It was found that both surface hydrophilicity and surface functionality are of great importance for cell adhesion and growth on starch‐based biomaterials.magnified image
Biodegradation of Aliphatic and Aromatic Polycarbonates
Authors: Artham Trishul , Doble Mukesh 
Published: September 2007

AbstractPolycarbonate is one of the most widely used engineering plastics because of its superior physical, chemical, and mechanical properties. Understanding the biodegradation of this polymer is of great importance to answer the increasing problems in waste management of this polymer. Aliphatic polycarbonates are known to biodegrade either through the action of pure enzymes or by bacterial whole cells. Very little information is available that deals with the biodegradation of aromatic polycarbonates. Biodegradation is governed by different factors that include polymer characteristics, type of organism, and nature of pretreatment. The polymer characteristics such as its mobility, tacticity, crystallinity, molecular weight, the type of functional groups and substituents present in its structure, and plasticizers or additives added to the polymer all play an important role in its degradation. The carbonate bond in aliphatic polycarbonates is facile and hence this polymer is easily biodegradable. On the other hand, bisphenol A polycarbonate contains benzene rings and quaternary carbon atoms which form bulky and stiff chains that enhance rigidity. Even though this polycarbonate is amorphous in nature because of considerable free volume, it is non‐biodegradable since the carbonate bond is inaccessible to enzymes because of the presence of bulky phenyl groups on either side. In order to facilitate the biodegradation of polymers few pretreatment techniques which include photo‐oxidation, γ‐ irradiation, or use of chemicals have been tested. Addition of biosurfactants to improve the interaction between the polymer and the microorganisms, and blending with natural or synthetic polymers that degrade easily, can also enhance the biodegradation.magnified image
Determination of the Propagation Rate Coefficient of Vinyl Pivalate Based on EPR Quantification of the Propagating Radical Concentration
Authors: Kubota Narimi , Kajiwara Atsushi , Zetterlund Per B. , Kamachi Mikiharu , Treurnicht Jeanne , Tonge Matthew P. , Gilbert Robert G. , Yamada Bunichiro 
Published: September 2007

AbstractThe propagation rate coefficient (kp) of the vinyl pivalate (VPi) has been determined from an EPR quantification of the concentration of propagating radicals. The polymerizations followed first‐order kinetics with respect to the monomer, and the concentration of propagating radicals did not vary with time. The chain lengths were estimated to be sufficiently large to not affect kp. The resulting Arrhenius parameters for kp of VPi in heptane are Ap = 1.39 × 107 dm3 · mol−1 · s−1 and Ep = 20.5 kJ · mol−1. They are very similar to those of vinyl acetate as previously determined by the PLP method. The present results thus indicate that EPR gives consistent kp values for vinyl esters.magnified image
Hybrid Nonlinear Optical Materials Containing Imidazole Chromophore through the Sol‐Gel Process
Authors: Cui Yuanjing , Qian Guodong , Chen Lujian , Wang Zhiyu , Wang Minquan 
Published: September 2007

AbstractA new sol‐gel hybrid film based on heterocyclic chromophore, namely 2‐[4′‐(N‐ethyl‐N‐hydroxyethyl)amino phenyl azo]‐4,5‐dicyanoimidazole (IZ), has been synthesized and characterized. The hybrid system possesses a high chromophore loading density up to 65 wt.‐% without observing a phase separation. The initial decomposition temperatures of the chromophore and hybrid material were determined to be 260 and 272 °C, respectively. Poled films show a fairly high and stable nonlinear optical (NLO) response, even at an elevated temperature.magnified image
Surface‐Functionalized, Ring‐Opening Metathesis Polymerization‐Derived Monoliths for Anion‐Exchange Chromatography
Authors: Eder Karoline , Huber Christian G. , Buchmeiser Michael R. 
Published: September 2007

AbstractRing‐opening metathesis polymerization (ROMP) was used for the synthesis of monolithic capillary columns with inner diameters of 200 µm. The resulting polymeric monoliths were characterized by inverse size‐exclusion chromatography (ISEC). Surface functionalization was carried out in situ using 2‐(N,N‐dimethylaminoethyl)norborn‐5‐ene‐2‐ylcarboxylic amide (1). The resulting functionalized monoliths were successfully used in anion‐exchange chromatography of oligodeoxynucleotides.magnified image
PAX6 is expressed in pancreatic adenocarcinoma and is downregulated during induction of terminal differentiation
Authors: Lang Deborah , Mascarenhas Joseph B. , Powell Sara K. , Halegoua Jason , Nelson Maria , Ruggeri Bruce A. 
Published: September 2007

AbstractTumors of the exocrine pancreas are a major cause of cancer death and have among the poorest prognosis of any malignancy. Following the “cancer stem cell hypothesis,” where tumors are believed to originate in tissue specific stem cells, we screened primary ductal pancreatic carcinomas and cell lines for the expression of possible stem cell factors. We find 32/46 (70%) of primary tumors and 9/10 (90%) of cell lines express PAX6. PAX6 is a transcription factor expressed throughout the pancreatic bud during embryogenesis but not in the mature exocrine pancreas. PAX proteins have also been implicated in maintaining stem cells in a committed but undifferentiated state but a role for PAX proteins in putative pancreas stem cells is not known. We induced a pancreatic carcinoma cell line, Panc‐1, to differentiate by transfecting wild‐type p53 and treating the cells with differentiation agents gastrin or butyrate. This treatment induces cells to terminally differentiate into a growth‐arrested cell with neurite‐like processes, express the terminal differentiation marker somatostatin and downregulate PAX6. This phenotype can be replicated by directly inhibiting PAX6 expression. These data support a model where PAX proteins are aberrantly expressed in tumors and downregulation leads to differentiation. © 2007 Wiley‐Liss, Inc.
TAE226‐Induced apoptosis in breast cancer cells with overexpressed Src or EGFR
Authors: Golubovskaya Vita M. , Virnig Christopher , Cance William G. 
Published: September 2007

AbstractFocal adhesion kinase, FAK is a 125 kDa nonreceptor tyrosine kinase that localizes to focal adhesions. FAK is overexpressed in human tumors and regulates cellular adhesion and survival signaling. We have shown previously that the dominant‐negative FAK, C‐terminal FAK‐CD, caused detachment and apoptosis in human breast cancer cells, and that overexpression of an activated form of Src tyrosine kinase or epidermal growth factor receptor, EGFR, suppressed FAK‐CD induced apoptotic effects in breast cancer cells. In the present study, we studied the effect of a novel FAK inhibitor, TAE226 (Novartis, Inc.), on the breast cancer cell lines. We used stable breast cancer cell lines overexpressing Src (MCF‐7‐Src and BT474‐Src) or overexpressing EGFR (BT474‐EGFR), and control breast cancer cell lines for the treatment with different doses of TAE226 drug. The detachment and apoptosis caused by TAE226 was analyzed and compared with the effect of the dominant‐negative adenoviral FAK‐CD. The TAE226 drug caused a dose‐dependent increase of detachment and apoptosis in both BT474 and MCF‐7‐Vector and Src cells and in BT474‐EGFR and BT474‐pcDNA3 cells. Additionally, TAE226 caused downregulation of Y397‐FAK, FAK and activation of PARP or caspase‐3 proteins. Both Src and EGFR‐overexpressing cells were not resistant to the TAE226 treatment compared to FAK‐CD treatment. In addition, normal breast MCF‐10A cell line was resistant to both TAE226 drug and to the Ad‐FAK‐CD inhibitor. Thus, inhibition of autophosphorylation activity of FAK with the TAE226 inhibitor at 10–20 µM is effective in causing apoptosis in breast cancer cells, resistant to the Ad‐FAK‐CD inhibitor that can be used effectively in therapy. © 2007 Wiley‐Liss, Inc.
Inducible nitric oxide synthase, nitrotyrosine and p53 mutations in the molecular pathogenesis of Barrett's esophagus and esophageal adenocarcinoma
Authors: Vaninetti Nadine M. , Geldenhuys Laurette , Porter Geoffrey A. , Risch Harvey , Hainaut Pierre , Guernsey Duane L. , Casson Alan G. 
Published: September 2007

AbstractNitric oxide (NO) has been implicated as a potential causative factor for endogenous p53 mutations in gastrointestinal malignancy. To investigate the role of NO in esophageal adenocarcinoma (EADC), we studied patterns of p53 mutations, expression of inducible nitric oxide synthase (iNOS) and the tissue accumulation of nitrotyrosine (NTS), a stable reaction product of NO and a marker for cellular protein damage, in human premalignant and malignant esophageal epithelia. Tissues were obtained from patients with gastroesophageal reflux disease (GERD)‐induced esophagitis (n = 76), Barrett's esophagus (BE; n = 119) and primary EADC (n = 54). DNA sequencing was used to characterize p53 mutations, RT‐PCR to study iNOS mRNA expression, and immunohistochemistry to study NTS. Relative to self‐matched normal epithelia, a progressive increase in iNOS mRNA expression was seen in GERD (30%; 23/76), BE (48%; 57/119), and EADC (63%; 34/54) tissues (P < 0.001). Among patients with EADC, elevated levels of NTS immunoreactivity were more frequent in tumors with p53 mutations (11/21; 52%) compared with tumors with wild‐type p53 (9/33; 27%; P = 0.063), and specifically in tumors with p53 mutations at CpG dinucleotides (10/12; 83%) compared with non‐CpG p53 mutations (1/9; 11%; P = 0.008). The increasing frequency of iNOS (mRNA) overexpression in GERD, BE and EADC supports the hypothesis that an active inflammatory process, most likely a consequence of GERD, underlies molecular progression to EADC. The highly significant association between NTS, reflecting chronic NO‐induced cellular protein damage, and endogenous p53 mutations at CpG dinucleotides, provides further evidence for a molecular link between chronic inflammation and esophageal malignancy. © 2007 Wiley‐Liss, Inc.