bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic profiling of bioactive Pancratium canariense extracts by GC‐MS
Authors: Torras‐Claveria Laura , Berkov Strahil , Jáuregui Olga , Caujapé Juli , Viladomat Francesc , Codina Carles , Bastida Jaume 
Published: December 2009

AbstractIntroduction – Pancratium canariense Ker Gawler is a plant species belonging to family Amaryllidaceae. Plants from this family are known to synthesise a particular type of bioactive compounds, named Amaryllidaceae alkaloids, which have shown AChE inhibitory activity.Objective – To perform the metabolite profiling of methanolic extracts from P. canariense in order to identify bioactive compounds.Methodology – Methanolic extracts from bulbs, leaves and fruits were separated into alkaloid‐free apolar and polar fractions, as well as alkaloid fractions, and subjected to AChE assay. Metabolite profiling of extracts and fractions of P. canariense was carried out by GC‐EI‐MS and LC‐ESI‐TOF‐MS.Results – AChE inhibitory activities of the alkaloid fractions at a concentration of 10  µg/mL were 29.80 ± 0.91, 40.93 ± 4.60 and 58.06 ± 1.18% for the bulbs, leaves and fruits, respectively. Seventy‐six metabolites—mono‐, di‐ and trisaccharides, fatty acids, amino acids, sterols as well as several Amaryllidaceae alkaloids—were detected. Further purification of the alkaloids from the methanolic extracts resulted in the detection of 31 compounds including several potent AChE inhibitors such as habranthine and galanthamine, and the structural elucidation of 3‐O‐acetylhabranthine, a new natural compound with potential AChE inhibitory activity.Conclusion – The described method resulted in effective integration of both GC‐EI‐MS and LC‐ESI‐TOF‐MS strategies, which permitted the identification of many metabolites, as well as the structural elucidation of new compounds with potential AChE inhibitory activity. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of nanosilica particles on the cure and physical properties of an epoxy thermoset resin
Authors: Pethrick Richard A , Miller Claire , Rhoney Ian 
Published: December 2009

AbstractMeasurements are reported on the cure and physical properties of an epoxy resin created using a functionalised nanosilica filler. The filled bisphenol A epoxy (Nanopox A410) contained 40 wt% silica nanoparticles and was blended with two bisphenol A resins of molecular weights of 355 and 1075 g mol−1, respectively. Cure was achieved using 3,3‐diaminodiphenylsulfone. The functionality of the mixture containing the epoxy nanoparticles was determined using NMR analysis. Cure times showed a progressive decrease with increasing silica level. Dynamic mechanical thermal analysis showed a decrease in the value of the glass transition temperature (Tg) with increasing silica level. Tg was further studied using differential scanning calorimetry. The ability of the nanosilica to create a stable network structure was demonstrated by the variation of the high‐temperature modulus with silica composition. Thermomechanical analysis carried out below and above Tg showed a progressive decrease in the expansion coefficients with increasing silica level, indicating the effectiveness of the functionalised silica nanoparticles in forming a network. The network formed during cure in the nano‐modified epoxy is unable to undergo the densification possible in the pure resin material and explains the observed lowering of Tg with increasing nanosilica content. Copyright © 2009 Society of Chemical Industry
Synthesis, characterization and (electro)chemical polymerization of triphenylamine‐end‐functionalized poly(ε‐caprolactone)
Authors: Bendrea Anca‐Dana , Vacareanu Loredana , Grigoras Mircea 
Published: December 2009

AbstractTriphenylamine‐based oligomers and polymers with linear, hyperbranched, star‐shaped or dendrimer architectures have been synthesized and studied due to their interesting electro‐optical properties. In many cases insoluble materials are obtained. In this study, we report the synthesis of grafted polytriphenylamine by chemical and electrochemical polymerization of triphenylamine‐end‐functionalized poly(ε‐caprolactone). Functionalized ε‐caprolactone oligomers were obtained by ring‐opening polymerization of ε‐caprolactone initiated by 4‐hydroxymethyltriphenylamine/stannous octanoate (tin 2‐ethylhexanoate). The ring‐opening polymerization of ε‐caprolactone using 4‐hydroxymethyltriphenylamine/stannous octanoate as initiating system provided ε‐caprolactone oligomers, with well‐defined molecular weights, containing a triphenylamine terminal group. Chemical and electrochemical coupling oxidation of the triphenylamine ends allowed the formulation of polyarylamines with ε‐caprolactone oligomers as grafts. Graft copolymers with an aryleneamine backbone and short poly(ε‐caprolactone) grafts were obtained by (electro)chemical oxidation of oligomers containing triphenylamine terminal groups. Copyright © 2009 Society of Chemical Industry
Sleep–wake functioning along the cancer continuum: focus group results from the Patient‐Reported Outcomes Measurement Information System (PROMIS®)
Authors: Flynn Kathryn E. , Shelby Rebecca A. , Mitchell Sandra A. , Fawzy Maria R. , Hardy N. Chantelle , Husain Aatif M. , Keefe Francis J. , Krystal Andrew D. , Porter Laura S. , Reeve Bryce B. , Weinfurt Kevin P. 
Published: December 2009

AbstractObjective: Cancer and its treatments disturb sleep–wake functioning; however, there is little information available on the characteristics and consequences of sleep problems associated with cancer. As part of an effort to improve measurement of sleep–wake functioning, we explored the scope of difficulties with sleep in a diverse group of patients diagnosed with cancer.Methods: We conducted 10 focus groups with patients recruited from the Duke University tumor registry and oncology/hematology clinics. Separate groups were held with patients scheduled to begin or currently undergoing treatment for breast, prostate, lung, colorectal, hematological, and other cancer types and with patients who were in posttreatment follow‐up. The content of the focus group discussions was transcribed and analyzed for major themes by independent coders.Results: Participants not only reported causes of sleep disturbance common in other populations, such as pain and restless legs, but they also reported causes that may be unique to cancer populations, including abnormal dreams, anxiety about cancer diagnosis and recurrence, night sweats, and problems with sleep positioning. Many participants felt that sleep problems reduced their productivity, concentration, social interactions, and overall quality of life. Many also shared beliefs about the increased importance of sleep when fighting cancer.Conclusions: The findings underscore the need for interventions that minimize the negative impact of cancer and its treatments on sleep. This study will inform efforts now underway to develop a patient‐reported measure of sleep–wake functioning that reflects the breadth of concepts considered important by patients with cancer. Copyright © 2009 John Wiley & Sons, Ltd.
Osmolytes modulate conformational exchange in solvent‐exposed regions of membrane proteins
Authors: Flores Jiménez Ricardo H. , Do Cao Marie‐Ange , Kim Miyeon , Cafiso David S. 
Published: December 2009

AbstractSite‐directed spin labeling (SDSL) was used to investigate local structure and conformational exchange in two bacterial outer‐membrane TonB‐dependent transporters, BtuB and FecA. Protecting osmolytes, such as polyethylene glycols (PEGs) are known to modulate a substrate‐dependent conformational equilibrium in the energy coupling motif (Ton box) of BtuB. Here, we demonstrate that a segment that is N‐terminal to the Ton box in BtuB, is in conformational exchange between ordered and disordered states with or without substrate. Protecting osmolytes shift this equilibrium to favor the more ordered, folded state. However, a segment of BtuB that is C‐terminal to the Ton box that is not solvent exposed is insensitive to PEGs. Protecting osmolytes also modulate a conformational equilibrium in the Ton box of FecA, with larger molecular weight PEGs producing the largest shifts in the conformational free energy. These data indicate that solvent‐exposed regions of these transporters undergo conformational exchange and that regions of these transporters that are involved in protein–protein interactions sample multiple conformational substates. The sensitivity to solute provides an explanation for differences seen between two high‐resolution structures of BtuB, which each likely represent one conformation from a subset of states that are normally sampled by the protein. This work also illustrates how SDSL and osmolytes may be used to characterize and quantitate conformational equilibria in membrane proteins.
FiberDock: Flexible induced‐fit backbone refinement in molecular docking
Authors: Mashiach Efrat , Nussinov Ruth , Wolfson Haim J. 
Published: December 2009

AbstractUpon binding, proteins undergo conformational changes. These changes often prevent rigid‐body docking methods from predicting the 3D structure of a complex from the unbound conformations of its proteins. Handling protein backbone flexibility is a major challenge for docking methodologies, as backbone flexibility adds a huge number of degrees of freedom to the search space, and therefore considerably increases the running time of docking algorithms. Normal mode analysis permits description of protein flexibility as a linear combination of discrete movements (modes). Low‐frequency modes usually describe the large‐scale conformational changes of the protein. Therefore, many docking methods model backbone flexibility by using only few modes, which have the lowest frequencies. However, studies show that due to molecular interactions, many proteins also undergo local and small‐scale conformational changes, which are described by high‐frequency normal modes. Here we present a new method, FiberDock, for docking refinement which models backbone flexibility by an unlimited number of normal modes. The method iteratively minimizes the structure of the flexible protein along the most relevant modes. The relevance of a mode is calculated according to the correlation between the chemical forces, applied on each atom, and the translation vector of each atom, according to the normal mode. The results show that the method successfully models backbone movements that occur during molecular interactions and considerably improves the accuracy and the ranking of rigid‐docking models of protein–protein complexes. A web server for the FiberDock method is available at: http://bioinfo3d.cs.tau.ac.il/FiberDock. Proteins 2010. © 2009 Wiley‐Liss, Inc.
Effects of fungicides onin vitrospore germination and mycelial growth of the phytopathogensLeptosphaeria maculansandL. biglobosa(phoma stem canker of oilseed rape)
Authors: Eckert Maria R , Rossall Stephen , Selley Andrew , Fitt Bruce DL 
Published: December 2009

AbstractBACKGROUND:Phoma stem canker, caused by the coexisting related fungal pathogensLeptosphaeria maculans(Des.) Ces. & de Not andL. biglobosaShoemaker & H Brun, is a major disease of winter oilseed rape in the UK. Annually, over 90% of UK crops receive at least one foliar application of fungicide, but little is known about the sensitivity of the more damagingL. maculansand the less damagingL. biglobosato these fungicides. The effects of flusilazole, tebuconazole and Methyl Benzimidazole Carbamate (MBC) fungicides (benomyl and carbendazim) on the germination of ascospores, conidia and germ tube growth of both species were examined. Isolates collected from different oilseed rape crops in England and Wales were assessed for their mycelial growth on fungicide‐amended medium, and ED50values were calculated.RESULTS:Leptosphaeria maculansandL. biglobosadiffered in their sensitivity to fungicides. Conidial germination ofL. maculanswas more sensitive to these fungicides than that ofL. biglobosa. Isolates ofL. maculanshad smaller ED50values for mycelial growth for all fungicides tested than isolates ofL. biglobosa.CONCLUSION:These results suggest that fungicide applications might affect the structure ofL. maculans/L. biglobosapopulations in UK winter oilseed rape crops. Copyright © 2009 Society of Chemical Industry
Modulus anomaly in magnesium matrix composites
Authors: Chowdhury A. S. M. F. , Mari D. , Schaller R. 
Published: December 2009

AbstractSeveral magnesium matrix composites were investigated by means of mechanical spectroscopy. A modulus anomaly has been observed in the composites reinforced with fibers while the phenomenon does not occur with particles. This effect is attributed to bonding and debonding of fibers to the matrix, which is due to thermal stress relaxation by motion of dislocations. The modulus anomaly depends strongly on the orientation of the glide plane of the dislocations with respect to the matrix–fiber interface and on the aspect ratio of the fibers.
Localization dynamics of biexcitons and electron–hole plasmas in GaN‐based mixed crystals
Authors: Hirano Daisuke , Tayagaki Takeshi , Yamada Yoichi , Kanemitsu Yoshihiko 
Published: December 2009

AbstractWe report time‐resolved photoluminescence (PL) spectra in highly excited AlxGa1−xN mixed crystals under band‐to‐band excitation. The PL dynamics of excitons and biexcitons reveals that the localization of excitons begins within a few picoseconds delay time and almost all the excitons relax into the localized band‐tail states within 10 ps delay time after laser excitations. The biexciton formation time of ∼2 ps is extracted from the rise time of the PL intensities of excitons and biexcitons. These results indicate that biexcitons are formed from the free excitons and that the exciton localization, due to the potential fluctuations in the mixed crystals, reduces the exciton–exciton collisions and the formation of free biexcitons.
Combining [13C6]‐phenylisothiocyanate and the Edman degradation reaction: a possible breakthrough for absolute quantitative proteomics together with protein identification
Authors: Oe Tomoyuki , Maekawa Masamitsu , Satoh Ryo , Lee Seon Hwa , Goto Takaaki 
Published: December 2009

AbstractThis manuscript describes the results of a preliminary experiment performed as ‘proof of concept’ of a novel approach to absolute quantitation of proteins without the use of standard proteins. Absolute quantitation remains a challenging issue in the proteomics field. Therefore, we propose a combination of [13C6]‐phenylisothiocyanate (PITC) and the Edman degradation reaction as a possible breakthrough. [13C6]‐PITC was synthesized from [13C6]‐aniline with O,O′‐di‐2‐pyridyl thiocarbonate to prepare [13C6]‐phenylthiohydantoin (PTH)‐amino acids as internal standards. Upon the Edman degradation reaction, it has been confirmed that a model protein, bovine serum albumin (BSA), releases the N‐terminal amino acid quantitatively as PTH‐Asp. The standard curve of PTH‐Asp against [13C6]‐PTH‐Asp showed good linearity (r2 = 0.9977). BSA could be quantified as PTH‐Asp using the standard curve. In addition, the residual des‐Asp1‐BSA provided sufficient information for further protein identification. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of phenolic and triterpenoid compounds in licorice and rat plasma by high‐performance liquid chromatography diode‐array detection, time‐of‐flight mass spectrometry and quadrupole ion trap mass spectrometry
Authors: Tan Guangguo , Zhu Zhenyu , Zhang Hai , Zhao Liang , Liu Yi , Dong Xin , Lou Ziyang , Zhang Guoqing , Chai Yifeng 
Published: December 2009

AbstractHigh‐performance liquid chromatography with diode‐array detection (HPLC/DAD), time‐of‐flight mass spectrometry (HPLC/TOFMS) and quadrupole ion trap mass spectrometry (HPLC/QITMS) were used for separation and identification of several compounds in licorice and rat plasma after oral administration of the herbal extract. Three phenolic compounds and one triterpenoid in licorice extract were unambiguously identified by comparing with the standard compounds. A formula database of known compounds in licorice was established, against which the other 42 compounds were identified effectively based on the accurate extract masses and formulae acquired by HPLC/TOFMS. In order to differentiate the isomers, tandem mass spectrometry was also used. The deduced fragmentation behaviors in QITMS were used to distinguish seven groups of isomers in licorice. By means of the three detectors, 46 compounds in licorice were identified. After oral administration of the extract, 25 compounds in rat plasma were detected and identified by comparing and contrasting the compounds measured in licorice with those in the plasma samples by HPLC/TOFMS. It is concluded that a rapid and effective method based on three analytical techniques was established, which is useful for identification of multiple compounds in licorice in vitro and in vivo. The result should be very useful for the quality control and curative mechanism study of licorice. Copyright © 2009 John Wiley & Sons, Ltd.
Non‐disturbing characterization of natural organic matter (NOM) contained in clay rock pore water by mass spectrometry using electrospray and atmospheric pressure chemical ionization modes
Authors: Huclier‐Markai Sandrine , Landesman Catherine , Rogniaux Hélène , Monteau Fabrice , Vinsot Agnes , Grambow Bernd 
Published: December 2009

AbstractWe have investigated the composition of the mobile natural organic matter (NOM) present in Callovo‐Oxfodian pore water using electrospray ionization mass spectrometry (ESI‐MS), atmospheric pressure chemical ionization mass spectrometry (APCI‐MS) and emission‐excitation matrix (EEM) spectroscopy. The generation of knowledge of the composition, structure and size of mobile NOM is necessary if one wants to understand the interactions of these compounds with heavy metals/radionuclides, in the context of environmental studies, and particularly how the mobility of these trace elements is affected by mobile NOM. The proposed methodology is very sensitive in unambiguously identifying the in situ composition of dissolved NOM in water even at very low NOM concentration, due to innovative non‐disturbing water sampling and ionization (ESI/APCI‐MS) techniques. It was possible to analyze a quite exhaustive inventory of the small organic compounds of clay pore water without proceeding to any chemical treatment at naturally occurring concentration levels. The structural features observed were mainly acidic compounds and fatty acids as well as aldehydes and amino acids. Copyright © 2009 John Wiley & Sons, Ltd.
Interactions between biological and abiotic pathways in the reduction of chlorinated solvents
Authors: Brown Richard A. , Mueller James G. , Seech Alan G. , Henderson James K. , Wilson John T. 
Published: December 2009

AbstractWhile biologically mediated reductive dechlorination continues to be a significant focus of chlorinated solvent remediation, there has been an increased interest in abiotic reductive processes for the remediation of chlorinated solvents. In situ chemical reduction (ISCR) uses zero‐valent iron (ZVI)–based technologies, such as nanoscale iron and bimetallic ZVI, as well as naturally occurring reduced minerals incorporating dual‐valent iron (DVI), such as magnetite, green rust, and iron sulfides that are capable of dechlorinating solvents. A more recent area of development in ISCR has been in combining biological and abiotic processes.There are several ways in which biological and abiotic processes can be combined. First, the interaction between the two may be “causative.” For example, the Air Force Center for Engineering and the Environment's biogeochemical reductive dechlorination (BiRD) technology combines a mulch barrier with hematite and gypsum to create an iron‐sulfide‐based reducing zone. Biodegradation under sulfate‐reducing conditions produces sulfide that combines with the hematite to form iron sulfides. As such, the BiRD technology is “causative”; the biological processes create reducing minerals. The biological generation of other reducing minerals such as magnetite, siderite, and green rust is feasible and is, with magnetite, observed in nature at some petroleum sites. A second type of interaction between abiotic and biotic processes is “synergistic.” For example, biological processes can enhance the activity of reduced metals/minerals. This is the basis of the EHC® ISCR technologies, which combine ZVI with a (slowly) degradable carbon substrate. This combination rapidly creates buffered, strongly reducing conditions, which result in more complete solvent degradation (i.e., direct mineralization). The extent and level of reducing activity commonly observed are much greater when both the carbon substrate and the ZVI are present. When the carbon substrate is expended, the reducing activity due to ZVI alone is much less. The understanding of biogeochemical processes and their impact on abiotic processes is still developing. As that understanding develops, new and improved methods will be created to enhance volatile organic compound destruction. © 2009 Wiley Periodicals, Inc.
Treatment of an explosives plume in groundwater using an organic mulch biowall
Authors: Ahmad Farrukh , Adamson David T. , Farhat Shahla K. 
Published: December 2009

AbstractA field demonstration of a mulch permeable reactive barrier (PRB), or “biowall,” as an in situ treatment technology for explosives in groundwater is summarized. Organic mulch consists of insoluble carbon biopolymers that are enzymatically hydrolyzed during decomposition to release aqueous total organic carbon (TOC). The released TOC is then available for microorganisms to use as an electron donor to transform electrophilic contaminants via reductive pathways. A 100‐foot‐long and 2‐foot‐thick mulch biowall was installed at the Pueblo Chemical Army Depot in Colorado to treat a shallow groundwater plume containing hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX). To discourage groundwater flow bypassing around and under the biowall in this highly permeable formation, a hydraulic control was installed and the PRB was keyed into the bedrock. Technology performance was monitored using a monitoring well network to establish the development and extent of the downgradient treatment zone. Performance objectives of the field demonstration were: (1) greater than 90 percent removal of RDX across the PRB and the treatment zone; (2) an RDX concentration of less than 0.55 μg/L in the treatment zone; and (3) cumulative toxic intermediate concentration (nitroso intermediates of RDX, MNX, DNX, and TNX) of less than 20 percent of the upgradient RDX concentration. All performance objectives were met within seven months after installation once the system reached a pseudo‐steady state. By this point, a sustained reducing/treatment zone had been created downgradient of the mulch PRB that showed greater than 93 percent RDX removal, RDX concentrations less than 0.55 μg/L, and no accumulation of toxic intermediates. The mulch biowall implemented during this demonstration was successful at meeting performance objectives while addressing the majority of potential concerns of the technology. © 2009 Wiley Periodicals, Inc.