bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gemcitabine and docetaxel (GEMDOX) for the treatment of relapsed and refractory pediatric sarcomas
Authors: Rapkin Louis , Qayed Muna , Brill Pam , Martin Melissa , Clark Dana , George Bradley A. , Olson Thomas A. , Wasilewski‐Masker Karen , Alazraki Adina , Katzenstein Howard M. 
Published: February 2012

AbstractBackgroundPatients with relapsed pediatric sarcomas have a poor outcome and are in need of novel effective therapies.MethodsWe retrospectively reviewed the records of patients at Children's Healthcare of Atlanta who were treated with gemcitabine (675 mg/m2) intravenously (IV) on Day 1 and Day 8, and docetaxel (75 mg/m2) IV on Day 8, repeated every 3 weeks.ResultsNineteen patients with a median age of 11 years were treated from 2006–2010 and received 123 total courses. Two patients (11%), both with rhabdomyosarcoma, demonstrated objectives responses [one complete response (CR) and one partial response (PR)]. Seven other patients (39%) had stable disease (SD). The 1‐year progression‐free survival (PFS) of the entire cohort was 24% ± 10% with a median time to progression of 2 months (range: 0.5–14 months). The 1‐year overall survival (OS) was 43% ± 11%. Grade 3 or 4 toxicities occurred in 14 patients (74%) and 52 courses (42%), and were most commonly hematologic (neutropenia = 37, anemia = 17, and thrombocytopenia = 23 courses).ConclusionsThe dismal outcomes for patients with relapsed and refractory sarcomas and the lack of effective sarcoma salvage regimens highlight the need for new approaches. This report of the therapeutic activity of gemcitabine and docetaxel (GEMDOX) in rhabdomyosarcoma and other pediatric reports describing activity in osteosarcoma and Ewing sarcoma suggest that this combination should be considered for formal evaluation in a pediatric specific clinical trial. At a minimum, it appears to offer a reasonable, tolerable, palliative option. Pediatr Blood Cancer 2012; 59: 854–858. © 2012 Wiley Periodicals, Inc.
Analysis and design of phase‐interleaving series‐connected module‐integrated converter for DC‐link ripple reduction of multi‐stage photovoltaic power systems
Authors: Jung An‐Yeol , Park Joung‐Hu , Jeon Hee‐Jong 
Published: February 2012

ABSTRACTRecently, installation of photovoltaic power systems such as building‐integrated photovoltaic in urban area has been spotlighted in renewable energy engineering field, even at the expense of the performance degradation from partial shading. The efficiency degradation of maximum power point tracking (MPPT) performance can be compensated by a kind of power‐conditioning system architecture such as module‐integrated converters (MIC), which can handle the optimal‐operation tracking for its own photovoltaic (PV) module. In case of a MIC with series‐connected outputs, it is easy to obtain a high DC‐link voltage for multiple stage PV power conditioning applications. However, switching ripple of the DC‐link voltage also increases as number of the modules increases.In this paper, as a solution for the ripple reduction, interleaved pulse width modulation‐phase synchronizing method is applied to the PV MIC modules. The switching‐ripple analysis of the MPPT power modules were performed and compared between the cases such as phase control or not. For the implementation of the phase control among the modules, Zigbee (XBee Pro, Digi International, Minnetonka, MN, USA) wireless communications transceiver and DSP (TMS320F28335, Texas Instruments, Dallas, TX, USA) series communications interface are utilized. Hardware prototype of the double‐module boost‐type 80‐W MICs has been built to validate the DC‐link voltage ripple reduction. Copyright © 2012 John Wiley & Sons, Ltd.
System memory effects in the sizing of stand‐alone PV systems
Authors: Fragaki Aikaterini , Markvart Tom 
Published: February 2012

ABSTRACTModels based on daily energy balance (or long‐term models) have been widely used as a tool in the stand‐alone photovoltaic (PV) system sizing, mainly with the purpose of obtaining analytical expressions of the relation between the generator size and the storage capacity of the battery. The system can then be designed to meet the reliability requirements of the specific case. However, such models represent the complex operation of a stand‐alone system in an oversimplified way. There is little research so far on the reliability and improvement of such models. Validation and possible modification of a long‐term system model requires comparison of the simulated state of charge (SOC) of the battery with that obtained from an experimental system. In this work, experimental data from a 6‐month operation of a basic stand‐alone PV system have been analysed and compared with modelling results. One obvious improvement that could be applied to the long‐term system model is to account for a charging efficiency of the battery, and this possibility is examined in the present work. However, comparison with the modelling results shows that the data cannot be fitted by simply taking into account battery inefficiency. A method to account for system memory effects in the increase of the battery SOC, imposed by the operation of the regulator, is necessary to accurately model the macroscopic diurnal charging/discharging process. Copyright © 2012 John Wiley & Sons, Ltd.
Control of thermal properties and hydrolytic degradation in poly(lactic acid) polymer stars through control of isospecificity of polymer arms
Authors: Cameron Donald J. A. , Shaver Michael P. 
Published: February 2012

AbstractThe synthesis of a family of polymer stars with arms of varied tacticities is discussed. The effect of polymer tacticity on the physical properties of these polymer stars is dramatic. Dipentaerythritol cores support six poly(lactic acid) arms. Lewis acidic tin and/or aluminum catalysts control the polymerization to afford polymer stars of variable tacticity. Analysis of these polymers by 1H NMR spectroscopy, thermogravimetric analysis, powder X‐ray diffraction, and differential scanning calorimetry reveals the effects of tacticity control on the physical properties of the polymer stars. Hydrolytic decomposition studies suggest that the degradation profile of a polymer star may also be tuned by stereochemical control. Differences between isotactic samples derived from rac‐lactide and L‐lactide are heightened by longer arms of 50 and 100 monomer units. Control of polymer isospecificity shows that a ∼70% isotacticity bias is necessary to induce crystallinity and alter the thermal and degradation properties of the material. Above 70% isotacticity, the degradation properties and thermal transitions can be further tuned across a relatively wide range. This technique allows for significant tunability to the physical properties of aliphatic polyester polymer stars. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Interactions of oligomers of organic polyethers with histidine amino acid
Authors: Zobnina Valentina G. , Kosevich Marina V. , Chagovets Vitaliy V. , Boryak Oleg A. , Vékey Károly , Gömöry Ágnes , Kulyk Anna N. 
Published: February 2012

AbstractRATIONALEKnowledge on noncovalent intermolecular interactions of organic polyethers with amino acids is essential to gain a better understanding on how polymers assemble in organic nanoparticles which are promising for drug delivery and cryoprotection. The main objective of the present study was to determine how polyethers assemble around ionizable amino acids such as histidine.METHODSElectrospray mass spectrometry was applied to probe the interactions in model systems consisting of polyethylene glycol PEG‐400 or oxyethylated glycerol OEG‐5 and amino acid histidine hydrochloride. Molecular dynamics simulation was utilized to visualize the structure of complexes of polyether oligomers with histidine in different charge states.RESULTSStable gas‐phase clusters composed of polyether oligomers (PEGn, OEGn) with protonated histidine ‐ PEGn•His•H+, OEGn•His•H+, OEGn•OEGm•His•H+ and chlorine counterion – PEGn•Cl‐, OEGn•Cl‐, were observed under electrospray conditions. Molecular dynamics simulation of representative polyether‐histidine complexes revealed the stabilization of oligomers by multiple hydrogen and coordination bonds whereby charged groups are wrapped by the polymeric chains.CONCLUSIONSThe self‐organization of polyether chains around the protonated imidazole group of histidine was revealed. This finding should be considered when modelling a pegylated protein structure and polyether‐based organic nanoparticles. Copyright © 2012 John Wiley & Sons, Ltd.
Analysis of cipadesin limonoids from Cipadessa cinerascens using electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry and quantum chemical calculations
Authors: Wu Zhi‐Jun , Sun Dong‐Ming , Chen Jian‐Zhong , Chen Xiao‐Zhen , Fang Dong‐Mei , Li Na , Cheng Ping , Zhang Guo‐Lin 
Published: February 2012

RATIONALELimonoids, a class of tetranortriterpenoids, exhibit various biological effects, such as insect antifeedant and growth regulating activities, antimicrobial activity, potent cell adhesion inhibitory effects, antimalarial activity, anticancer activities, and antioxidant activity. The potential application brings the need for reliable, fast and low‐cost analysis of this class of compounds.METHODSSix cipadesin limonoids (1–6), including a pairs of isomers, from leaves and barks of Cipadessa cinerascens were investigated by electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (ESI‐QTOF‐MS/MS) in positive‐ion mode. Characteristic processes were further studied by theoretical calculations.RESULTS1,3‐Hydrogen rearrangement might play a significant role in the cleavage of ‐O‐ bridge bond in ring B and further produces some characteristic ions. For [M + Na]+ precursor ions, the product ion at m/z 133 might indicate the structure of ring A and the losses of CO2 and AcOH occur readily. Interestingly, the radical product ion at m/z 460 from [M + Na]+ ions seems to be the characteristic ion for compound 1. A deuterium‐labeling experiment supported the processes forming the radical ion. For [M + NH4]+ ions, high‐abundance product ions resulting from sequential loss of AcOH can be observed. In addition, a pairs of isomers was unambiguously differentiated based on MS or MS/MS spectra.CONCLUSIONSIn summary, sufficient information obtained from fragmentation experiments of [M + Na]+, [M + NH4]+ or [M + H]+ precursor ions is especially valuable for rapid identification of these limonoids or their metabolites in complex mixtures. The high‐abundance radical product ion is of scientific interest. Copyright © 2012 John Wiley & Sons, Ltd.
Perfluorooctanoic acid and ammonium perfluorooctanoate: volatile surfactants for proteome analysis?
Authors: Vieira Douglas B. , Crowell Andrew M. J. , Doucette Alan A. 
Published: February 2012

RATIONALEFluorinated surfactants are being explored as mass spectrometry (MS)‐friendly alternatives to sodium dodecyl sulfate (SDS) for proteome analysis. Previous work demonstrates perfluorooctanoic acid (PFOA) to be compatible with electrospray ionization (ESI)‐MS. The high volatility of PFOA provides an intrinsic approach to potentially eliminate the surfactant during ESI, or alternatively through solvent evaporation prior to MS. The ammonium salt of PFOA, ammonium perfluorooctanoate (APFO), is likely favored for proteome experiments; the MS and liquid chromatography (LC)/MS tolerance of APFO has not been established for proteome applications.METHODSStandard proteins and peptides, as well as a yeast proteome mixture, were individually spiked with surfactants (APFO, PFOA, SDS), and subjected to direct infusion ESI‐MS, LC/MS/MS and LC/UV. The level of fluorinated surfactant remaining after solvent evaporation under varying conditions (time, pH, salt and protein content) was quantified and compared to the threshold tolerance level of the surfactant in an MS experiment (determined herein).RESULTSWhereas PFOA is found ineffective at assisting protein solubilization, APFO is as effective as SDS for resolubilization of acetone‐precipitated yeast proteins (~100% recovery). Unfortunately, the LC and MS threshold tolerance of APFO is only minimally greater than SDS (~2‐fold higher concentration to cause 50% suppression). Nonetheless, the benefits of APFO in a proteome experiment are realized following a one‐step evaporation protocol for removal of the surfactant in acidified solvent.CONCLUSIONSAPFO is considered a favoured alternative to SDS for proteome solubilization. Strictly speaking, APFO is not an 'MS‐friendly' surfactant for proteome characterization; the detergent not only suppresses ESI signals at high concentration, but also perturbs reversed phase separation. However, the simplicity of APFO removal ahead of LC/MS justifies its use over the conventional SDS. Copyright © 2012 John Wiley & Sons, Ltd.
Using complementary mass spectrometric approaches for the determination of methylprednisolone metabolites in human urine
Authors: Pozo Oscar J. , Marcos Josep , Matabosch Xavier , Ventura Rosa , Segura Jordi 
Published: February 2012

RATIONALEThe metabolism of methylprednisolone is revisited in order to find new metabolites that could be important for distinguishing between different routes of administration. Recently developed liquid chromatography/tandem mass spectrometry (LC/MS/MS) strategies for the detection of corticosteroid metabolites have been applied to the study of methylprednisolone metabolism.METHODSThe structures of these metabolites were studied using two complementary mass spectrometric techniques: LC/MS/MS in product ion scan mode with electrospray ionization and gas chromatography/mass spectrometry (GC/MS) in full scan mode with electron ionization. Metabolites were also isolated by semipreparative liquid chromatography fractionation. Each fraction was divided into two aliquots; one was studied by LC/MS/MS and the other by GC/MS after methoxyamine‐trimethylsilyl derivatization.RESULTSThe combination of all the structural information allowed us to propose a comprehensive picture of methylprednisolone metabolism in humans. Overall, 15 metabolites including five previously unreported compounds have been detected. Specifically, 16β,17α,21‐trihydroxy‐6α‐methylpregna‐1,4‐diene‐3,11,20‐trione, 17α,20β,21‐trihydroxy‐6α‐methylpregna‐1,4‐diene‐3, 11‐dione, 11β,17α,21‐trihydroxy‐6α‐hydroxymethylpregna‐1,4‐diene‐3,20‐dione, 11β,17α,20ξ,21‐tetrahydroxy‐6α‐hydroxymethylpregna‐1,4‐diene‐3‐one, and 17α,21‐dihydroxy‐6α‐hydroxymethylpregna‐1,4‐diene‐3,11,20‐trione are proposed as feasible structures for the novel metabolites. In addition to the expected biotransformations: reduction of the C20 carbonyl, oxidation of the C11 hydroxy group, and further 6β‐hydroxylation, we propose that hydroxylation of the 6α‐methyl group can also take place.CONCLUSIONSNew metabolites have been identified in urine samples collected after oral administration of 40 mg of methylprednisolone. All identified metabolites were found in all samples collected up to 36 h after oral administration. However, after topical administration of 5 g of methylprednisolone aceponate, neither the parent compound nor any of the metabolites were detected. Copyright © 2012 John Wiley & Sons, Ltd.
Improved accuracy in high‐temperature conversion elemental analyzer δ18O measurements of nitrogen‐rich organics
Authors: Hunsinger Glendon B. , Stern Libby A. 
Published: February 2012

RATIONALEThe use of high‐temperature conversion (HTC) reduction systems interfaced with isotope ratio mass spectrometers for δ18O measurements of nitrogen‐containing organic materials is complicated by isobaric interference from 14N16O+. This ion is produced in the ion source when N2 reacts with trace oxygen shifting the m/z 30 baseline prior to elution of CO.METHODSWe compared adaptations to a typical HTC system (TC/EA) to determine the best method to measure the δ18O values of nitrogen‐rich organic substrates including: (1) 0.6 and 1.5 m 5 Å molecular sieve GC columns; (2) reduction of N2 peak via He dilution; and (3) diversion of N2 to waste via an automated four‐port valve. These methods were applied to caffeine (IAEA‐600), glycine, 4‐nitroacetanilide, pentaerythritol tetranitrate (PETN) and cyclotrimethylene trinitramine (RDX), as well as pure and sodium azide‐doped benzoic acid (IAEA‐601) and sucrose (IAEA‐CH6).RESULTSThe efficiency of N2 production in the HTC interface was highly variable among these compounds. Both the longer column and the dilutor improved, but did not eliminate, the adverse effects of nitrogen.CONCLUSIONSThe diversion of N2 adequately addressed the nitrogen‐induced problems as indicated by: (1) consistent m/z 30 background offset between reference and sample CO for both N‐free and N‐rich materials; (2) production of the highest δ18O values; and (3) high correlation between the increase in the δ18O values relative to the GC‐only measurements and the N2 peak area. Additional validation would require N‐rich oxygen isotope standards for inter‐laboratory comparisons. Further, more stringent methodology may improve the poor inter‐laboratory δ18O reproducibility of IAEA‐600. Published in 2012 by John Wiley & Sons, Ltd.
Generation of negative ions from SF6 gas by means of hot surface ionization
Authors: Pelc Andrzej 
Published: February 2012

RATIONALESulfur hexafluoride (SF6) is a man‐made compound with many industrial applications. This compound is also one of the most powerful greenhouse gases with a relatively long atmospheric lifetime. Therefore, it is important to investigate processes leading to SF6 decomposition.METHODSA magnetic sector mass spectrometer with a thermoemission gaseous ion source was used in this study. The filament temperature was changed and monitored pyrometrically during the course of the studies. In the hot surface ionization process, negative ions may be generated both by free electron attachment to a molecule and by thermal dissociation followed by electron capture to the one of the fragments formed.RESULTSEight ion species: SF5–, F–, SF6–, SF4–, SF3–, SF2–, SF– and F2–, with ion current intensities ratios of 1000:200:100:10:5:0.5:0.5:0.05, respectively, were detected. The filament temperature dependencies of the SF5–, F–, SF6–, SF4– ion current intensities were measured. The optimal temperatures at which the maximum of the ion current intensity is observed were estimated in the 1830–2000 ± 10 °C range. The formation of F2– ions is probably disturbed by a dissociation process at high temperatures.CONCLUSIONSNegative surface ionization on the hot filament is a relatively simple and effective method for carrying out negative ion formation studies. Eight SF6 decomposition channels leading to the formation of negative ions have been detected and analyzed using this technique. Copyright © 2012 John Wiley & Sons, Ltd.
In vitro three‐dimensional aortic vasculature modeling based on sensor fusion between intravascular ultrasound and magnetic tracker
Authors: Shi Chaoyang , Tercero Carlos , Ikeda Seiichi , Ooe Katsutoshi , Fukuda Toshio , Komori Kimihiro , Yamamoto Kiyohito 
Published: February 2012

AbstractBackgroundIt is desirable to reduce aortic stent graft installation time and the amount of contrast media used for this process. Guidance with augmented reality can achieve this by facilitating alignment of the stent graft with the renal and mesenteric arteries.MethodsFor this purpose, a sensor fusion is proposed between intravascular ultrasound (IVUS) and magnetic trackers to construct three‐dimensional virtual reality models of the blood vessels, as well as improvements to the gradient vector flow snake for boundary detection in ultrasound images. In vitro vasculature imaging experiments were done with hybrid probe and silicone models of the vasculature.ResultsThe dispersion of samples for the magnetic tracker in the hybrid probe increased less than 1 mm when the IVUS was activated. Three‐dimensional models of the descending thoracic aorta, with cross‐section radius average error of 0.94 mm, were built from the data fusion.ConclusionThe development of this technology will enable reduction in the amount of contrast media required for in vivo and real‐time three‐dimensional blood vessel imaging. Copyright © 2012 John Wiley & Sons, Ltd.
Developing a Millifluidic Platform for the Synthesis of Ultrasmall Nanoclusters: Ultrasmall Copper Nanoclusters as a Case Study
Authors: Biswas Sanchita , Miller Jeffrey T. , Li Yuehao , Nandakumar Krishnaswamy , Kumar Challa S. S. R. 
Published: February 2012

AbstractThe future of lab‐on‐a‐chip devices for the synthesis of nanomaterials hinges on the successful development of high‐throughput methods with better control over their size. While significant effort in this direction mainly focuses on developing “difficult to fabricate” complex microfluidic reactors, scant attention has been paid to the “easy to fabricate” and simple millifluidic systems that could provide the required control as well as high throughput. By utilizing numerical simulation of fluids within the millifluidic space at different flow rates, the results presented here show velocity profiles and residence time distributions similar to the case of microfluidics. By significantly reducing the residence time and residence time distribution, a continuous flow synthesis of ultrasmall copper nanoclusters (UCNCs) with exceptional colloidal stability is achieved. In‐situ synchrotron‐radiation‐based X‐ray absorption spectroscopy (XAS) reveal that the as‐prepared clusters are about 1 nm, which is further supported by transmission electron microscopy and UV–vis spectroscopy studies. The clusters reported here are the smallest ever produced using a lab‐on‐a‐chip platform. When supported on silica, they are found to efficiently catalyze C–H oxidation reactions, hitherto unknown to be catalyzed by Cu. This work suggests that a millifluidic platform can be an inexpensive, versatile, easy‐to‐use, and powerful tool for nanoparticle synthesis in general, and more specifically for ultrasmall nanoclusters (UNCs).
Pharmacological characterization of the norepinephrine and dopamine reuptake inhibitor EB‐1020: Implications for treatment of attention‐deficit hyperactivity disorder
Authors: Bymaster Frank P. , Golembiowska Krystyna , Kowalska Magdalena , Choi Yong Kee , Tarazi Frank I. 
Published: February 2012

AbstractWe report on the pharmacological, behavioral, and neurochemical characterization of a novel dual norepinephrine (NE)/dopamine (DA) transporter inhibitor EB‐1020 (1R,5S)‐1‐(naphthalen‐2‐yl)‐3‐azabicyclo[3.1.0]hexane HCl). EB‐1020 preferentially inhibited monoamine reuptake in cloned cell lines transfected with human transporters with IC50 values of 6 and 38, respectively, for NE and DA transporters. In microdialysis studies, EB‐1020 markedly increased NE, and DA concentrations levels in rat prefrontal cortex in vivo with peak increases of 375 and 300%, respectively with the greatest effects on NE, and also increased DA extracellular concentrations in the striatum to 400% of baseline concentrations. Behavioral studies demonstrated that EB‐1020 dose‐dependently decreased immobility in the mouse tail suspension test of depression to 13% of control levels, and did not stimulate locomotor activity in adult rats in the optimal dose range. EB‐1020 dose‐dependently inhibited locomotor hyperactivity in juvenile rats lesioned with the neurotoxin 6‐hydroxydopamine (100 μg intracisternally) as neonates; a well‐established animal model for attention‐deficit hyperactivity disorder (ADHD). These data suggest that EB‐1020 mediates its actions by stimulating NE and DA neurotransmission, which are typically impaired in ADHD. Synapse, 2012. © 2012 Wiley Periodicals, Inc.