bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of drugs of forensic interest with capillary zone electrophoresis/time‐of‐flight mass spectrometry based on the use of non‐volatile buffers
Authors: Gottardo Rossella , Mikšík Ivan , Aturki Zeineb , Sorio Daniela , Seri Catia , Fanali Salvatore , Tagliaro Franco 
Published: March 2012

Abstracthe present work is aimed at investigating the influence of the background electrolyte composition and concentration on the separation efficiency and resolution and mass spectrometric detection of illicit drugs in a capillary zone electrophoresis‐electrospray ionization‐time of flight mass spectrometry (CZE‐ESI‐TOF MS) system. The effect of phosphate, borate and Tris buffers on the separation and mass spectrometry response of a mixture of 3,4‐methylenedioxyamphetamine, 3,4‐methylenedioxymethamphetamine, methadone, cocaine, morphine, codeine and 6‐monoacetylmorphine was studied, in comparison with a reference ammonium formate separation buffer. Inorganic non‐volatile borate and Tris buffers proved hardly suitable for capillary electrophoresis‐mass spectrometry (CE‐MS) analysis, but quite unexpectedly ammonium phosphate buffers showed good separation and ionization performances for all the analytes tested. Applications of this method to real samples of hair from drug addicts are also provided.
CE‐ESI‐MS separation of divalent organic and inorganic anions using a tricationic complexing reagent
Authors: Gerardi Anthony R. , Lin Xiuli , Breitbach Zachary S. , Armstrong Daniel W. , Colyer Christa L. 
Published: March 2012

AbstractA tricationic ion‐pairing reagent, 1,3,5‐1‐butyl‐3‐methyl‐1H‐imidazol‐3‐ium‐2,4,6‐trimethylbenzene, was used to form complexes with doubly charged anions for their subsequent analysis by capillary electrophoresis‐electrospray ionization‐mass spectrometry (CE‐ESI‐MS) in the positive‐ion mode. This methodology offers the advantages of greater versatility and sensitivity relative to direct detection of the anions in negative‐ion mode, and it can be realized by a number of possible complexation strategies, including pre‐column, on‐column, and post‐column modes. Three model anions, sulfate [SO42−], thiosulfate [TSFA, S2O32−], and benzenedisulfonate [BZDS, C6H4(SO3)22−], were amenable to complexation with the tricationic reagent, yielding singly charged cations with greater mass‐to‐charge (m/z) ratios than the native analytes. By utilizing optimized parameters obtained through previous work with dicationic reagents and singly charged anions, including the CE separation buffer composition and pH, the concentration of the dicationic reagent, the mode of complexation, the nebulizing gas pressure, and the sheath liquid composition, it was possible to develop a robust CE‐ESI‐MS method appropriate for the analysis of divalent anions in a mixture.
An optimized electrochemistry‐liquid chromatography‐mass spectrometry method for studying guanosine oxidation
Authors: Erb Robert , Plattner Sabine , Pitterl Florian , Brouwer Hendrik‐Jan , Oberacher Herbert 
Published: March 2012

AbstractOxidative stress can disrupt the integrity of genetic material. Due to its importance in the pathogenesis of different kinds of disease, including neurodegenerative disease, cardiovascular disease and cancer, major efforts are put into the elucidation of mechanisms involved. Herein, the combination of electrochemistry/liquid chromatography/mass spectrometry (EC/LC/MS) is presented as convenient, fast and simple method to study nucleic acids oxidation. Guanosine was selected as test compound. 8‐Hydroxyguanosine and (guanosine‐H)2 were identified as primary oxidation products. Oxidation was accomplished in an electrochemical thin‐layer cell integrated in the flow path of the autosampler of the chromatographic system. The reaction mixture was separated and mass analyzed by LC/MS. The use of LC was found to be particularly beneficial to resolve isobaric oxidation products. Another advantage of the setup used was the ability to decouple the electrochemical cell and the electrospray ionization source from each other eliminating any kind of cell potential interaction. Separation of EC from LC/MS, furthermore, facilitates method optimization. Experimental parameters were optimized for both techniques independently. Highest yields and best detectability of oxidation products were obtained with 10 mM ammonium formate at physiological pH delivered at a flow rate of 2.5‐5 μL/min through the electrochemical cell.
A neurosteroid analogue photolabeling reagent labels the colchicine‐binding site on tubulin: A mass spectrometric analysis
Authors: Chen Zi‐Wei , Chen Li‐Hai , Akentieva Natalia , Lichti Cheryl F. , Darbandi Ramin , Hastings Randy , Covey Douglas F. , Reichert David E. , Townsend R. Reid , Evers Alex S. 
Published: March 2012

AbstractPrevious studies have shown that the neurosteroid analogue, 6‐Azi‐pregnanolone (6‐AziP), photolabels voltage‐dependent anion channels and proteins of approximately 55 kDa in rat brain membranes. The present study used two‐dimensional electrophoresis and nanoelectrospray ionization ion‐trap mass spectrometry (nano‐ESI‐MS) to identify the 55 kDa proteins (isoelectric point 4.8) as isoforms of β‐tubulin. This identification was confirmed by immunoblot and immunoprecipitation of photolabeled protein with anti‐β‐tubulin antibody and by the demonstration that 6‐AziP photolabels purified bovine brain tubulin in a concentration‐dependent pattern. To identify the photolabeling sites, purified bovine brain tubulin was photolabeled with 6‐AziP, digested with trypsin, and analyzed by matrix‐assisted laser desorption/ionization MS (MALDI). A 6‐AziP adduct of TAVCDIPPR(m/z = 1287.77), a β‐tubulin specific peptide, was detected by MALDI. High‐resolution liquid chromatography‐MS/MS analysis identified that 6‐AziP was covalently bound to cysteine 354 (Cys‐354), previously identified as a colchicine‐binding site. 6‐AziP photolabeling was inhibited by 2‐methoxyestradiol, an endogenous derivative of estradiol thought to bind to the colchicine site. Structural modeling predicted that neurosteroids could dock in this colchicine site at the interface between α‐ and β‐tubulin with the photolabeling group of 6‐AziP positioned proximate to Cys‐354.
Poly(glycidyl methacrylate‐divinylbenzene) based immobilized pH gradient capillary isoelectric focusing coupling with MALDI mass spectrometry for enhanced neuropeptide analysis
Authors: Zhang Zichuan , Wang Junhua , Hui Limei , Li Lingjun 
Published: March 2012

AbstractHerein, we report an immobilized pH gradient (IPG) capillary isoelectric focusing‐matrix‐assisted laser desorption/ionization mass spectrometry (CIEF‐MALDI MS) platform designed for the separation of complex neuropeptides. This platform features a poly(glycidyl methacrylate‐divinylbenzene) (GMA‐DVB)‐based monolithic column for CIEF separation. Different from regular CIEF, carrier ampholytes are preimmobilized on the monolithic surface instead of being added to the sample. An off‐line coupling of IPG‐CIEF to MALDI MS has been established. Comparison with regular CIEF and optimizations are performed with bovine serum albumin tryptic peptides and extracted neuropeptide mixtures from crustacean Callinectes sapidus. It has been demonstrated that the separation of complex peptide mixtures in neutral and basic pH ranges can be achieved in less than 10 min with comparable separation efficiency with regular CIEF, while the MS signal is significantly enhanced when employing IPG‐CIEF. Enhanced neuropeptide detection is also observed after coupling IPG‐CIEF with MALDI MS.
Rapid screening of catalytic pyrolysis reactions of Organosolv lignins with the vTI‐mini fast pyrolyzer
Authors: Choi Hang Seok , Meier Dietrich , Windt Michael 
Published: March 2012

AbstractThe vTI‐mini fast pyrolyzer was applied for screening fast pyrolysis reactions of different Organosolv lignins, such as Alcell (Repap Technologies) and lignin from a German biorefinery project. To investigate the catalytic effects on the pyrolysis of the technical lignins, three catalysts such as zeolite HZSM‐5, FCC, and Olivine were used. The catalytic pyrolysis characteristics and decomposition products of the Organosolv lignins were scrutinized by varying pyrolysis temperature and catalyst type. From the pyrolysis experiments, obtained pyrolyzed products were generally categorized into three parts such as coke, noncondensable gas, and biocrude oil. To evaluate the yield of biocrude oil, mass balances of products and reactants were established and the collected biocrude oil was analyzed by GC/MS. From the results, the increase or decrease patterns of certain chemical compounds were found according to the different pyrolysis temperatures as well as various catalysts. In particular, size exclusion chromatography (SEC) was performed for extracts of the solid residue to get information on the catalytic effect and severity of lignin degradation. © 2012 American Institute of Chemical Engineers Environ Prog, 2012
Mineral nutrient recovery from pyrolysis systems
Authors: Wise Jatara , Vietor Donald , Provin Tony , Capareda Sergio , Munster Clyde , Boateng Akwasi 
Published: March 2012

AbstractBioenergy plants such as sorghum, bioenergy rice, corn stover, and switchgrass can be thermochemically converted by pyrolysis to produce bio‐oil, synthesis gas from noncondensable gases, and biochar. The biochar fraction can be recycled back to the production field to improve soil physical qualities and nutrient status. Although previous publications have described the beneficial effects of pyrolysis biochar on soil physical properties; relatively little has been published on the recovery of mineral nutrients from pyrolysis co‐products. This work quantified the recovery of nutrients (P, K, Ca, and Mg) from pyrolysis coproducts from various feedstocks using two distinct reactors. Nutrient mass balances, on a feedstock basis, were calculated for comparison of the two reactors' efficiency in the recovery of the nutrients. The results revealed the recovery of nutrients varied by (1) species, (2) reactor design, and (3) correlated highly with nutrient mass loss in biochar. Computations also revealed P recoveries of 93% (fixed‐bed reactor) and 58% and 55% (fluidized‐bed reactor) for pyrolyzed sorghum. The recovery of key mineral nutrients in pyrolysis coproducts (primarily biochar) is directly related to the feasibility of nutrient recycling through biochar. © 2012 American Institute of Chemical Engineers Environ Prog, 2012
Secondary reactions of levoglucosan and char in the fast pyrolysis of cellulose
Authors: Ronsse Frederik , Bai Xianglan , Prins Wolter , Brown Robert C. 
Published: March 2012

AbstractIn fast pyrolysis of cellulose, levoglucosan is often reported as the most abundant primary decomposition product. Char, the solid residue of pyrolysis is thought to catalyze secondary reactions that decompose levoglucosan into water and additional, secondary char. A CDS Analytical Pyroprobe 5200 was used to pyrolyze pure cellulose to levoglucosan and the generated vapors were passed through a temperature‐controlled tubular reactor filled with material to be tested for catalytic activity and then to a GC‐FID for analysis. Carbonaceous materials included as‐received and acid‐washed char derived from pyrolysis of red oak and, pure graphite. Acid‐washed red oak char and pure graphite had little effect on levoglucosan decomposition compared with the empty tubular reactor for the range of tubular reactor temperatures studied (200–400°C). In contrast, unwashed red oak char significantly reduced the amount of levoglucosan when the tubular reactor was operated above 300°C. These results suggest that metals—which are removed through the procedure of acid washing—rather than the fixed carbon in the char, catalyze the decomposition of levoglucosan in the vapor phase. © 2012 American Institute of Chemical Engineers Environ Prog, 2012
Lactones 38: Synthesis and odoriferous properties of p‐menthane lactones
Authors: Dams Iwona , Białońska Agata , Ciunik Zbigniew , Wawrzeńczyk Czesław 
Published: March 2012

ABSTRACTAn enantiomeric pair of bicyclic δ‐lactones with the p‐menthane system was obtained from enantiomerically pure isomers of (1R,2S,5R)‐(–) and (1S,2R,5S)‐(+)‐isopulegol. The Horner–Wadsworth–Emmons olefination of isopulegones followed by hydrolysis of esters and lactonization of acids were the key steps of the syntheses presented. The structures of the compounds were determined by both spectroscopic and crystallographic methods. Enantiomeric p‐menthane esters and δ‐lactones are characterized by interesting odoriferous properties. Copyright © 2012 John Wiley & Sons, Ltd.
Application of the Jacobi–Davidson method to accurate analysis of singular linear hydrodynamic stability problems
Authors: Gheorghiu C.I. , Rommes J. 
Published: March 2012

SUMMARYThe aim of this paper is to show that the Jacobi–Davidson (JD) method is an accurate and robust method for solving large generalized algebraic eigenvalue problems with a singular second matrix. Such problems are routinely encountered in linear hydrodynamic stability analysis of flows that arise in various areas of continuum mechanics. As we use the Chebyshev collocation as a discretization method, the first matrix in the pencil is nonsymmetric, full rank, and ill‐conditioned. Because of the singularity of the second matrix, QZ and Arnoldi‐type algorithms may produce spurious eigenvalues. As a systematic remedy of this situation, we use two JD methods, corresponding to real and complex situations, to compute specific parts of the spectrum of the eigenvalue problems. Both methods overcome potentially severe problems associated with spurious unstable eigenvalues and are fairly stable with respect to the order of discretization. The real JD outperforms the shift‐and‐invert Arnoldi method with respect to the CPU time for large discretizations. Three specific flows are analyzed to advocate our statements, namely a multicomponent convection–diffusion in a porous medium, a thermal convection in a variable gravity field, and the so‐called Hadley flow. Copyright © 2012 John Wiley & Sons, Ltd.
Neuroplasticity‐based computerized cognitive remediation for geriatric depression
Authors: Morimoto Sarah Shizuko , Wexler Bruce E. , Alexopoulos George S. 
Published: March 2012

ObjectiveThis article describes a novel treatment model designed to target specific neurocognitive deficits in geriatric depression with neuroplasticity‐based computerized cognitive remediation (NBCCR).MethodThe recent National Institute of Mental Health (NIMH) report “From Discovery to Cure” calls for studies focusing on mechanisms of treatment response with the goal of arriving at new interventions for those who do not respond to existing treatments. We describe the process that led to the identification of specific executive deficits and their underlying neurobiology, as well as the rationale for targeting these symptoms as a part of a strategy intended to improve both executive dysfunction and depression. We then propose a strategy for further research in this emerging areaResults and ConclusionsDespite significant developments, conventional antidepressant treatments leave many older adults still depressed and suffering. Psychotherapy may be effective in some depressed elders, although a recent review concluded that none of the available treatment studies meets stringent criteria for efficacy in the acute treatment of geriatric depression. Appropriately developed and targeted NBCCR, has the potential to serve as a novel treatment intervention for geriatric depression. Pathophysiological changes associated with executive dysfunction may be an appropriate target for NBCCR. Examining both behavioral changes and indices of structural integrity and functional change of networks related to cognitive and emotional regulation may lead to a novel treatment and elucidate the role of specific cerebral networks in geriatric depression. Copyright © 2012 John Wiley & Sons, Ltd.
Neurocognitive functioning in early‐onset and late‐onset older patients with euthymic bipolar disorder
Authors: Martino Diego J. , Strejilevich Sergio A. , Manes Facundo 
Published: March 2012

ObjectiveMost neurocognitive studies have not taken into account the fact that older patients with bipolar disorder (BD) are a heterogeneous population. The main goal of this study was to compare neurocognitive performance and extrapyramidal symptoms in older patients with early‐onset BD (EO‐BD) and late‐onset BD (LO‐BD).MethodsEuthymic older patients with EO‐BD (n = 20), LO‐BD (n = 20), and healthy controls (n = 20) were evaluated with traditional clinical instruments and measures of exposure to psychotropic drugs, as well as extrapyramidal symptoms. All subjects completed an extensive neuropsychological battery.ResultsPatients with EO‐BD showed poorer performance than healthy controls in two measures of verbal memory and two measures of executive functions, whereas patients with LO‐BD exhibited lower performance scores than healthy controls in almost all of the measures assessed. Impairments in the LO‐BD group included even neurocognitive domains typically spared in mixed‐age patients. Additionally, there was a trend toward displaying higher extrapyramidal symptoms in the LO‐BD group compared with both EO‐BD and healthy control groups. In both patient groups, psychosocial functioning was related with executive dysfunction and extrapyramidal symptoms.ConclusionsPatients with LO‐BD may have more extensive and severe cognitive impairments, as well as higher vulnerability to extrapyramidal symptoms, compared with patients with EO‐BD. Cognitive–motor disturbances may help to explain impairments in daily functioning among older patients with EO‐BD and LO‐BD during remission. Copyright © 2012 John Wiley & Sons, Ltd.
Estimates of changes in design rainfall values for Canada
Authors: Burn Donald H. , Taleghani Amir 
Published: March 2012

AbstractAnnual maximum rainfall data from 51 stations in Canada were analyzed for trends and changes by using the Mann–Kendall trend test and a bootstrap resampling approach, respectively. Rainfall data were analyzed for nine durations ranging from 5 min to 24 h. The data analyzed are typically used in the development of intensity‐duration‐frequency (IDF) curves, which are used for estimating design rainfall values that form an input for the design of critical water infrastructure. The results reveal more increasing than decreasing trends and changes in the data with more increasing changes and larger changes, noted for the longer rainfall durations. The results also indicate that a traditional trend test may not be sufficient when the interest is in identifying changes in design rainfall quantiles. Copyright © 2012 John Wiley & Sons, Ltd.
Automated measurement of spontaneous pain‐associated limb movement and drug efficacy evaluation in a rat model of neuropathic pain
Authors: Kawasaki‐Yatsugi S. , Nagakura Y. , Ogino S. , Sekizawa T. , Kiso T. , Takahashi M. , Ishikawa G. , Ito H. , Shimizu Y. 
Published: March 2012

AbstractBackgroundThe withdrawal response elicited by a nociceptive stimulus, i.e., evoked pain measure, is commonly used as an efficacy endpoint in neuropathic pain animal models. It, however, has several limitations, which highlight the importance of examining spontaneous pain. The present study describes an automated method for measuring spontaneous pain behaviour in a rat model of neuropathic pain caused by chronic constriction injury (CCI) of sciatic nerve.MethodsAfter CCI surgery, a small magnet was implanted into the operated limb. The rat was placed in a test chamber that was surrounded by wire coil. Limb movements, including lifting/guarding, flinching/shaking, licking and walking in the operated limb, caused changes in the electromagnetic field, including a change in voltage and transformed into a signal via an amplifier.ResultsCCI rats consistently showed more frequent limb movement than sham rats. There was no significant correlation between the frequency of spontaneous pain behaviour and the evoked pain symptoms. Treatment with duloxetine (30 mg/kg p.o.) and amitriptyline (30 and 100 mg/kg p.o.) significantly reduced this frequency. Pregabalin at 30 mg/kg p.o. tended to reduce the frequency, and diclofenac up to 10 mg/kg p.o. had no effect.ConclusionA non‐subjective automated method for measuring spontaneous pain behaviour in an animal model of neuropathic pain was established. It is expected that the current system will greatly enhance the analysis of spontaneous pain‐related behaviour, which is a predominant symptom in patients with neuropathic pain. The current system may also be valuable in the screening of potential analgesic treatments.
Fabrication of chitosan/hydroxylapatite composite rods with a layer‐by‐layer structure for fracture fixation
Authors: Pu Xi‐Ming , Sun Zhen‐Zhen , Hou Zhen‐Qing , Yang Yun , Yao Qing‐Qing , Zhang Qi‐Qing 
Published: March 2012

AbstractA composite rod for fracture fixation using chitosan (CHI)/hydroxylapatite (HA) was prepared by means of in situ precipitation, which had a layer‐by‐layer structure, good mechanical properties, and cell compatibilities. The CHI/HA composite rods were precipitated from the chitosan solution with calcium and phosphorus precursors, followed by treatment with a tripolyphosphate–trisodium phosphate solution (pH >13) to crosslink the CHI and to hydrolyze the calcium phosphates to nanocrystalline HA. The results of FTIR, XRD, and TEM measurements confirmed that HA had been formed within the CHI matrix. The effects of the CHI/HA ratios (20/0, 20/1, 20/2, 20/4, and 20/5, w/w) on the mechanical properties were investigated. At the CHI/HA ratio of 20/4 (w/w), the bending strength and modulus of the rods were 133 MPa and 6.8 GPa, respectively. Pre‐osteoblast MC3T3‐E1 cells were cultured in an extract of the CHI/HA rods (20/4, w/w) to study the cell compatibilities of the composite. The observations indicated that the CHI/HA composite could promote the growth of MC3T3‐E1 cells better than the composite without HA (p < 0.05). Furthermore, the co‐cultivation of the cells and the CHI/HA composite showed that cells fully spread on the surface of the composite with an obvious cytoskeleton organization, which also revealed that the CHI/HA composite had a good biocompatibility. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 1179–1189, 2012.
Effect of crystallization heat treatment on the microstructure of niobium‐doped fluorapatite glass‐ceramics
Authors: Denry I. , Holloway J. A. , Gupta P. K. 
Published: March 2012

AbstractOur goal was to study the effect of heat treatment temperature and heating rate on the microstructure and crystalline phases and assess the domain of existence of submicrometer fluorapatite crystals in niobium‐doped fluorapatite glass‐ceramics for biomedical applications. Glass‐ceramic specimens were prepared by casting and heat treatment between 700 and 1200°C using a fast or a slow heating rate. The microstructure was characterized by atomic force microscopy and scanning electron microscopy. Crystalline phases were analyzed by x‐ray diffraction. AFM of the as‐cast glass revealed that amorphous phase separation occurred in this system. XRD confirmed the presence of fluorapatite in all specimens, together with forsterite and enstatite at higher temperatures. Both heating rate and heat treatment temperature strongly influenced microstructure and crystallinity. A dual microstructure with submicrometer fluorapatite crystals and polygonal forsterite crystals was obtained when slow heating rates and crystallization temperatures between 950 and 1100°C were used. Needle‐shaped fluorapatite crystals appeared after heat treatment above 1100°C. Fast heating rates led to an increase in crystal size. Heat treatment temperatures should remain below 1100°C, together with slow heating rates, to prevent crystal dissolution, and preserve a dual microstructure of finely dispersed submicrometer crystals without growth of needle‐shaped crystals. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B:1198–1205, 2012.