bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blueberry anthocyanins and pyruvic acid adducts: anticancer properties in breast cancer cell lines
Authors: Faria Ana , Pestana Diogo , Teixeira Diana , de Freitas Victor , Mateus Nuno , Calhau Conceição 
Published: June 2010

AbstractThe purpose of this study was to investigate the anticancer properties of an anthocyanin‐pyruvic acid adduct extract, which is being developed aiming to be further applied in the food industry. An anthocyanin extract from blueberry (extract I) and an anthocyanin‐pyruvic acid adduct extract (extract II) were tested on two breast cancer cell lines (MDA‐MB‐231 and MCF7). Proliferation was assessed by SRB assay and 3H‐thymidine incorporation. Caspase‐3 activity was determined in the presence of both extracts. Their capacity as chemoattractants and their invasive potential were also assayed.In both cell lines, extracts I and II significantly reduced cell proliferation at 250 μg/mL, after 24 h of cell incubation. Caspase‐3 activity was not altered by the extracts (250 μg/mL) in either cell line, with the exception of extract II in MCF‐7, which increased its activity, probably explaining its effects on cell proliferation.Both extracts (250 μg/mL) demonstrated significant antiinvasive potential in both cell lines. Furthermore, they did not demonstrate any capacity for chemotaxis.In conclusion, blueberry anthocyanins and the respective anthocyanin‐pyruvic acid adducts demonstrated anticancer properties by inhibiting cancer cell proliferation and by acting as cell antiinvasive factors and chemoinhibitors. The anthocyanin‐pyruvic acid adduct extract showed a more pronounced effect in MDA‐MB‐231, suggesting an effect independent of estrogen receptors. Copyright © 2010 John Wiley & Sons, Ltd.
Cycloartane triterpenoids from Cimicifuga yunnanensis induce apoptosis of breast cancer cells (MCF7) via p53‐dependent mitochondrial signaling pathway
Authors: Fang Zhong‐Ze , Nian Yin , Li Wei , Wu Jing‐Jing , Ge Guang‐Bo , Dong Pei‐Pei , Zhang Yan‐Yan , Qiu Ming‐Hua , Liu Lei , Yang Ling 
Published: June 2010

AbstractThe present study was carried out to investigate the antitumor activity of five cycloartane triterpenoids isolated from Cimicifuga yunnanensis on the breast cancer cell line MCF7 and its corresponding drug resistant subline R‐MCF7, including cimigenol‐3‐O‐β‐d‐xylopyranoside (compound 1), 25‐O‐acetylcimigenol‐3‐O‐β‐d‐xylopyranoside (compound 2), 25‐chlorodeoxycimigenol‐3‐O‐β‐d‐xylopyranoside (compound 3), 25‐O‐acetylcimigenol‐3‐O‐α‐l‐arabinopyranoside (compound 4) and 23‐O‐acetylcimigenol‐3‐O‐β‐d‐xylopyranoside (compound 5). The results showed that compounds 2–5 have relatively high antitumor activity on both MCF7 and R‐MCF7 cells. The involvement of apoptosis as a major cause of cycloartane triterpenoids‐induced cell death was further confirmed. The results of RT‐PCR showed that compounds 2–5 increased the expression of p53 and bax, which led to the loss of mitochondrial potential and then resulted in the activation of caspase‐7. These findings collectively demonstrated that compounds 2–5 induced apoptosis of MCF7 via p53‐dependent mitochondrial pathway. Copyright © 2010 John Wiley & Sons, Ltd.
Methylation of acidic moieties in poly(methyl methacrylate‐co‐methacrylic acid) copolymers for end‐group characterization by tandem mass spectrometry
Authors: Giordanengo Rémi , Viel Stéphane , Hidalgo Manuel , Allard‐Breton Béatrice , Thévand André , Charles Laurence 
Published: June 2010

AbstractThe complete structural characterization of a copolymer composed of methacrylic acid (MAA) and methyl methacrylate (MMA) units was achieved using tandem mass spectrometry. In a first step, collision‐induced dissociation (CID) of sodiated MAA‐MMA co‐oligomers allowed us to determine the co‐monomeric composition, the random nature of the copolymer and the sum of the end‐group masses. However, dissociation reactions of MAA‐based molecules mainly involve the acidic pendant groups, precluding individual characterization of the end groups. Therefore, methylation of all the acrylic acid moieties was performed to transform the MAA‐MMA copolymer into a PMMA homopolymer, for which CID mainly proceeds via backbone cleavages. Using trimethylsilyldiazomethane as a derivatization agent, this methylation reaction was shown to be complete without affecting the end groups. Using fragmentation rules established for PMMA polymers together with accurate mass measurements of the product ions and knowledge of reagents used for the studied copolymer synthesis, a structure could be proposed for both end groups and it was found to be consistent with signals obtained in nuclear magnetic resonance spectra. Copyright © 2010 John Wiley & Sons, Ltd.
Quadrupole mass filters with added hexapole fields
Authors: Xiao Zilan , Zhao XianZhen , Douglas D. J. 
Published: June 2010

AbstractConventional mass analysis has been investigated experimentally with six quadrupole mass filters with added hexapole fields; three with added hexapole fields of 4%, 8% and 12% with equal diameter rods, and three with added hexapole fields of 4%, 8% and 12% with unequal diameter rods to remove an added octopole field. Compared with conventional quadrupoles, these rod sets have very large field distortions. With the positive resolving dc applied to the y rods (Mathieu parameter $a_{x} < 0$) only low resolution (10–100) and low transmission are seen. With the polarity reversed ($a_{x} > 0$) much higher resolution (≥1000) and transmission are possible. Increasing the magnitude of the added hexapole field decreases the limiting resolution at m/z 609. Removing the added octopole field increases the limiting resolution. In some cases structure is formed on the peaks. For a given scan line slope, U/V

rf
, the resolution decreases as the amplitude of the added hexapole field increases. These results are consistent with changes to the stability diagrams, calculated here. With $a_{x} > 0$, adding a hexapole field causes the x stability boundary to move outward with all rod sets. With $a_{x} < 0$, the boundaries become diffuse and the tip of the stability diagram becomes rounded, limiting the resolution to ca. 10‐100. Where comparisons are possible, experiments show the rod sets with added hexapole fields have transmission 10–300 times less than a conventional quadrupole. Thus these quadrupoles are less useful for mass analysis than conventional quadrupoles. However, it is surprising, given the highly distorted fields, that some of the quadrupoles give resolution of 1000 or more. Copyright © 2010 John Wiley & Sons, Ltd.
Application of laser ablation multicollector inductively coupled plasma mass spectrometry for the measurement of calcium and lead isotope ratios in packaging for discriminatory purposes
Authors: Santamaria‐Fernandez Rebeca , Wolff Jean‐Claude 
Published: June 2010

AbstractThe potential of high‐precision calcium and lead isotope ratio measurements using laser ablation coupled to multicollector inductively coupled plasma mass spectrometry (LA‐MC‐ICP‐MS) to aid distinction between four genuine and five counterfeit pharmaceutical packaging samples and further classification of counterfeit packaging samples has been evaluated. We highlight the lack of reference materials for LA‐MC‐ICP‐MS isotope ratio measurements in solids. In this case the problem is minimised by using National Institute of Standards and Technology Standard Reference Material (NIST SRM) 915a calcium carbonate (as solid pellets) and NIST SRM610 glass disc for sample bracketing external standardisation. In addition, a new reference material, NIST SRM915b calcium carbonate, has been characterised in‐house for Ca isotope ratios and is used as a reference sample. Significant differences have been found between genuine and counterfeit samples; the method allows detection of counterfeits and aids further classification of packaging samples. Typical expanded uncertainties for measured‐corrected Ca isotope ratio values (43Ca/44Ca and 42Ca/44Ca) were found to be below 0.06% (k = 2, 95% confidence) and below 0.2% for measured‐corrected Pb isotope ratios (207Pb/206Pb and 208Pb/206Pb). This is the first time that Ca isotope ratios have been measured in packaging materials using LA coupled to a multicollector (MC)‐ICP‐MS instrument. The use of LA‐MC‐ICP‐MS for direct measurement of Ca and Pb isotopic variations in cardboard/ink in packaging has definitive potential to aid counterfeit detection and classification. Copyright © 2010 John Wiley & Sons, Ltd.
Error assessment of nitrogen and oxygen isotope ratios of nitrate as determined via the bacterial denitrification method
Authors: Xue Dongmei , De Baets Bernard , Vermeulen Jan , Botte Jorin , Van Cleemput Oswald , Boeckx Pascal 
Published: June 2010

AbstractCurrently, bacterial denitrification is becoming the accepted method for δ15N‐ and δ18O‐NO determination. However, proper correction methods with international references (USGS32, USGS34 and USGS35) are needed. As a consequence, it is important to realize that the corrected isotope values are derived from a combination of several other measurements with associated uncertainties. Therefore, it is necessary to consider the propagated uncertainty on the final isotope value. This study demonstrates how to correctly estimate the uncertainty on corrected δ15N‐ and δ18O‐NO values using a first‐order Taylor series approximation. The bacterial denitrification method errors from 33 batches of 561 surface water samples varied from 0.2 to 2.1‰ for δ15N‐NO and from 0.7 to 2.3‰ for δ18O‐NO, which is slightly wider than the machine error, which varied from 0.2 to 0.6‰ for δ15N‐N2O and from 0.4 to 1.0‰ for δ18O‐N2O. The overall uncertainties, which are composed of the machine error and the method error, for the 33 batches ranged from 0.3 to 2.2‰ for δ15N‐NO and from 0.8 to 2.5‰ for δ18O‐NO. In addition, the mean corrected δ15N and δ18O values of 132 KNO3‐IWS (internal working standard) measurements were computed as 8.4 ± 1.0‰ and 25.1 ± 2.0‰, which is a slight underestimation for δ15N and overestimation for δ18O compared with the accepted values (δ15N = 9.9 ± 0.3‰ and δ18O = 24.0 ± 0.3‰). The overall uncertainty of the bacterial denitrification method allows the use of this method for source identification of NO. Copyright © 2010 John Wiley & Sons, Ltd.
Identification of complex, naturally occurring flavonoid glycosides in kale (Brassica oleracea var. sabellica) by high‐performance liquid chromatography diode‐array detection/electrospray ionization multi‐stage mass spectrometry
Authors: Schmidt Susanne , Zietz Michaela , Schreiner Monika , Rohn Sascha , Kroh Lothar W. , Krumbein Angelika 
Published: June 2010

AbstractKale is a member of the Brassicaceae family and has a complex profile of flavonoid glycosides. Therefore, kale is a suitable matrix to discuss in a comprehensive study the different fragmentation patterns of flavonoid glycosides. The wide variety of glycosylation and acylation patterns determines the health‐promoting effects of these glycosides. The aim of this study is to investigate the naturally occurring flavonoids in kale. A total of 71 flavonoid glycosides of quercetin, kaempferol and isorhamnetin were identified using a high‐performance liquid chromatography diode‐array detection/electrospray ionization multi‐stage mass spectrometry (HPLC‐DAD/ESI‐MSn) method. Of these 71 flavonol glycosides, 27 were non‐acylated, 30 were monoacylated and 14 were diacylated. Non‐acylated flavonol glycosides were present as mono‐, di‐, tri‐ and tetraglycosides. This is the first time that the occurrence of four different fragmentation patterns of non‐acylated flavonol triglycosides has been reported in one matrix simultaneously. In addition, 44 flavonol glycosides were acylated with p‐coumaric, caffeic, ferulic, hydroxyferulic or sinapic acid. While monoacylated glycosides existed as di‐, tri‐ and tetraglycosides, diacylated glycosides occurred as tetra‐ and pentaglycosides. To the best of our knowledge, 28 compounds in kale are reported here for the first time. These include three acylated isorhamnetin glycosides (isorhamnetin‐3‐O‐sinapoyl‐sophoroside‐7‐O‐D‐glucoside, isorhamnetin‐3‐O‐feruloyl‐sophoroside‐7‐O‐diglucoside and isorhamnetin‐3‐O‐disinapoyl‐triglucoside‐7‐O‐diglucoside) and seven non‐acylated isorhamnetin glycosides. Copyright © 2010 John Wiley & Sons, Ltd.
Software tool for mining liquid chromatography/multi‐stage mass spectrometry data for comprehensive glycerophospholipid profiling
Authors: Hein Eva‐Maria , Bödeker Bertram , Nolte Jürgen , Hayen Heiko 
Published: June 2010

AbstractElectrospray ionization mass spectrometry (ESI‐MS) has emerged as an indispensable tool in the field of lipidomics. Despite the growing interest in lipid analysis, there are only a few software tools available for data evaluation, as compared for example to proteomics applications. This makes comprehensive lipid analysis a complex challenge. Thus, a computational tool for harnessing the raw data from liquid chromatography/mass spectrometry (LC/MS) experiments was developed in this study and is available from the authors on request. The Profiler‐Merger‐Viewer tool is a software package for automatic processing of raw‐data from data‐dependent experiments, measured by high‐performance liquid chromatography hyphenated to electrospray ionization hybrid linear ion trap Fourier transform mass spectrometry (FTICR‐MS and Orbitrap) in single and multi‐stage mode. The software contains three parts: processing of the raw data by Profiler for lipid identification, summarizing of replicate measurements by Merger and visualization of all relevant data (chromatograms as well as mass spectra) for validation of the results by Viewer. The tool is easily accessible, since it is implemented in Java and uses Microsoft Excel (XLS) as output format. The motivation was to develop a tool which supports and accelerates the manual data evaluation (identification and relative quantification) significantly but does not make a complete data analysis within a black‐box system. The software's mode of operation, usage and options will be demonstrated on the basis of a lipid extract of baker's yeast (S. cerevisiae). In this study, we focused on three important representatives of lipids: glycerophospholipids, lyso‐glycerophospholipids and free fatty acids. Copyright © 2010 John Wiley & Sons, Ltd.
Post‐interface signal suppression, a phenomenon observed in a single‐stage Orbitrap mass spectrometer coupled to an electrospray interfaced liquid chromatograph
Authors: Kaufmann A. , Widmer M. , Maden K. 
Published: June 2010

AbstractSignal suppression is a common issue when analyzing compounds by liquid chromatography coupled to mass spectrometry (LC/MS/MS). Suppression of signals is caused by co‐eluting matrix compounds and is thought to take place in the interface. This paper reports strong signal suppression effects which were observed when using a single‐stage Orbitrap instrument which was coupled by an electrospray interface to a liquid chromatograph. This type of signal suppression (often the complete loss of certain analyte signal) is observed in addition to signal suppression originating in the electrospray interface. The location of where this phenomenon occurs was shown to be clearly beyond the interface region. It was suspected that not the Orbitrap cell itself, but the C‐trap, which is an integral part within the Orbitrap instrument, was the probable location. Such post‐interface signal suppression was observed – and could be experimentally induced – when multiply charged ions (e.g. electrospray protonated proteins) were co‐eluting with the analytes. High concentrations of proteins, yet not exceeding the maximum ion capacity of the trap, can cause a complete loss of all low m/z masses. This paper describes the practical implication when analyzing heavy matrix samples and discusses strategies to reduce such detrimental effects. Copyright © 2010 John Wiley & Sons, Ltd.
Proton transfer reaction time‐of‐flight mass spectrometry monitoring of the evolution of volatile compounds during lactic acid fermentation of milk
Authors: Soukoulis Christos , Aprea Eugenio , Biasioli Franco , Cappellin Luca , Schuhfried Erna , Märk Tilmann D. , Gasperi Flavia 
Published: June 2010

AbstractWe apply, for first time, the recently developed proton transfer reaction time‐of‐flight mass spectrometry (PTR‐TOF‐MS) apparatus as a rapid method for the monitoring of lactic acid fermentation (LAF) of milk. PTR‐TOF‐MS has been proposed as a very fast, highly sensitive and versatile technique but there have been no reports of its application to dynamic biochemical processes with relevance to the food industry.LAF is a biochemical‐physicochemical dynamic process particularly relevant for the dairy industry as it is an important step in the production of many dairy products. Further, LAF is important in the utilization of the by‐products of the cheese industry, such as whey wastewaters.We show that PTR‐TOF‐MS is a powerful method for the monitoring of major volatile organic chemicals (VOCs) formed or depleted during LAF, including acetaldehyde, diacetyl, acetoin and 2‐propanone, and it also provides information about the evolution of minor VOCs such as acetic acid, 2,3‐pentanedione, ethanol, and off‐flavor related VOCs such as dimethyl sulfide and furfural. This can be very important considering that the conventional measurement of pH decrease during LAF is often ineffective due to the reduced response of pH electrodes resulting from the formation of protein sediments. Solid‐phase microextraction gas chromatography/mass spectrometry (SPME‐GC/MS) data on the inoculated milk base and final fermented product are also presented to supporting peak identification. We demonstrate that PTR‐TOF‐MS can be used as a rapid, efficient and non‐invasive method for the monitoring of LAF from headspace, supplying important data about the quality of the final product and that it may be used to monitor the efficacy of manufacturing practices. Copyright © 2010 John Wiley & Sons, Ltd.
Direct profiling of phospholipids and lysophospholipids in rat brain sections after ischemic stroke
Authors: Wang Hay‐Yan J. , Liu Cheng Bin , Wu Hsuan‐Wen , Kuo Jr Shin 
Published: June 2010

AbstractStroke, a deleterious cerebrovascular event, is caused by a critical reduction in the blood flow to the brain parenchyma that leads to brain injury and loss of brain functions. The inflammatory responses following ischemia often aggravate the neurological damage. Several pro‐inflammatory mediators released after stroke are closely related to the metabolism of phospholipids. In this study we directly profiled the changes in phospholipids in the infarcted rat cerebral cortex 24 hours after middle cerebral artery occlusion (MCAO) using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). Several phosphatidylcholine (PC) species and sphingomyelin (SM) were significantly decreased after infarction. The cationization pattern of the remaining PCs showed a prominent shift from a mostly potassiated or protonated form to a predominantly sodiated pattern. Stroke also elevated the lysophosphatidylcholines (LPCs) and heme in tissue. The isobaric pairs in PC and LPC classes were resolved by masses through their respective alkali metal adducts in the presence of CsCl. The major fatty acyl LPC species were also structurally confirmed by MALDI‐MS/MS. Overall, the results described the changes in PC and LPC species in the infarcted rat cortex. The elevated tissue levels of LPCs and heme signify the ongoing pathological lipid breakdown and the state of parenchymal inflammation. The elevated LPC level in tissue suggests a means of intervention through lysophospholipid metabolism that could potentially benefit the management of stroke and other acute neurological injuries. Copyright © 2010 John Wiley & Sons, Ltd.
Fragmentation studies and electrospray ionization mass spectrometry of lapachol: protonated, deprotonated and cationized species
Authors: Vessecchi Ricardo , Emery Flavio S. , Galembeck Sérgio E. , Lopes Norberto P. 
Published: June 2010

AbstractElectrospray ionization mass spectrometric analysis of lapachol (2‐hydroxy‐3‐(3‐methyl‐2‐butenyl)‐1,4‐naphthoquinone) was accomplished in order to elucidate the gas‐phase dissociation reactions of this important biologically active natural product. The occurrence of protonated and cationized species in the positive mode and of deprotonated species in the negative mode was explored by means of collision‐induced dissociation (CID) experiments. For the protonated molecule, the H2O and C4H8 losses occur by two competitive channels. For the deprotonated molecule, the even‐electron rule is not conserved, and the radicalar species are eliminated by formation of distonic anions. The fragmentation mechanism for each ion was suggested on the basis of computational thermochemistry. Atomic charges, relative energies, and frontier orbitals were employed aiming at a better understanding of the gas‐phase reactivity of lapachol. Potential energy surfaces for fragmentation reactions were obtained by the B3LYP/6‐31+G(d,p) model. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of substituent groups at the 3‐position on the mass spectral fragmentation pathways of cephalosporins
Authors: Li Jin , Zhang Dou‐sheng , Chong Xiao‐meng , Hu Chang‐qin 
Published: June 2010

AbstractThe structural fragment ions of nine cephalosporins were studied by electrospray ionization quadrapole trap mass spectrometry (Q‐Trap MSn) in positive mode. The influence of substituent groups in the 3‐position on fragmentation pathway B, an α‐cleavage between the C7C8 single bond, coupled with a [2,4]‐trans‐Diels‐Alder cleavage simultaneously within the six‐membered heterocyclic ring, was also investigated. It was found that when the substituent groups were methyl, chloride, vinyl, or propenyl, fragmentations belonging to pathway B were detected; however, when the substituents were heteroatoms such as O, N, or S, pathway B fragmentation was not detected. This suggested that the [M–R3]+ ion, which was produced by the bond cleavage within the substituent group at the 3‐position, had a key influence on fragmentation pathway B. This could be attributed to the strong electronegativity of the heteroatoms (O, N, S) that favors the production of the [M–R3]+ ion. Moreover, having the positive charge of the [M–R3]+ ion localized on the nitrogen atom in the 1‐position changed the electron density distribution of the heterocyclic structure, which prohibits a [2,4]‐reverse‐Diels‐Alder fragmentation and as a result fragmentation pathway B could not occur. The influence of the substituent group in the 3‐position was determined by the intensity ratio (e/d) of ions produced by fragmentation pathway A, a [2,2]‐trans‐Diels‐Alder cleavage within the quaternary lactam ring, including the breaking of the amide bond and the C6C7 single bond (ion d), and fragmentation pathway B (ion e). The results indicate that the electronegativity of the substituent group was a key influencing factor of pathway B fragmentation intensity, because the intensity ratio (e/d) is higher for a chlorine atom, a vinyl, or a propenyl group than that of a methyl group. This study provided some theoretical basis for the identification of cephalosporin antibiotics and structural analysis of related substances in drugs. Copyright © 2010 John Wiley & Sons, Ltd.