bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of self‐hardening bainitic cast steel
Authors: Zhou H. , Wu Z.‐W. , Fu H. 
Published: October 2013

AbstractBainitic cast steel is a kind of wear resistant material which has high strength and toughness, and can usually be obtained by isothermal quenching or molybdenum alloying. However, isothermal quenching has lower production efficiency and molybdenum alloying has higher production cost. In this paper, according to the characteristics that manganese and boron elements delayed the pearlitic transformation, the authors developed a new type of self‐hardening bainitic cast steel in which manganese and boron were main alloy elements and a small amount of titanium, nitrogen, calcium, barium and yttrium elements were also added in the steel that could refine and purify the solidification structure of steel. On this basis, the author studied the effect of tempering treatment on microstructures, mechanical properties and wear resistance of bainitic cast steel. The results showed that impact toughness of bainitic cast steel increased ceaselessly with the increase of tempering temperature, and there was tempering brittleness while tempering from 450°C–500°C. Moreover, the hardness of bainitic cast steel decreased with the increase of tempering temperature, and hardness decreased slowly and maintained at 55HRC or above when tempering temperature was lower than 300°C. Under the condition of two‐body pin‐on‐disc wear, the wear resistance of bainitic cast steel decreased with the increase of tempering temperature, but bainitic cast steel tempering at 300°C had excellent wear resistance in the condition of impact wear. In the practical use, the bucket teeth of excavator and the hammer of crusher making from self‐hardening bainitic cast steel were safe and reliable, and their service life were increased by 120–150% than Hadfield manganese steel.
Resistin derived from diabetic perivascular adipose tissue up‐regulates vascular expression of osteopontin via the AP‐1 signalling pathway
Authors: Park So Youn , Kim Kyu Hee , Seo Kyo Won , Bae Jin Ung , Kim Yun Hak , Lee Seung Jin , Lee Won Suk , Kim Chi Dae 
Published: October 2013

AbstractPerivascular adipose tissue (PVAT) is implicated in the development of vascular diseases; however, the roles of PVAT on OPN expression in diabetic vasculature remain to be determined. This study investigated the role of adipokines derived from diabetic PVAT in regulating the vascular expression of OPN and explored the mechanisms involved. Aortic sections of ob/ob and high‐fat diet (HFD)‐induced obese (DIO) mice showed an increased expression of OPN, which was paralleled by increased amounts of PVAT characterized by enlargement of adipocytes. In the earlier phase of HFD feeding, macrophage infiltration was mainly localized to the area of PVAT at which adipocytes were enlarged, suggesting a potential link of activated adipocytes to macrophage infiltration. PVAT sections of ob/ob and DIO mice revealed a significantly greater number of macrophages with increased expression of adipokines, including resistin and visfatin. The distribution of resistin in PVAT mostly co‐localized with macrophages, while visfatin was expressed in macrophages and other cells. In in vitro studies, OPN expression in vascular smooth muscle cells (VSMCs) co‐cultured with PVAT of DIO mice was significantly increased, which was attenuated by a resistin‐neutralizing antibody. Likewise, resistin up‐regulated expression of OPN mRNA and protein in cultured VSMCs and the pivotal role of AP‐1 in resistin‐induced OPN transcription was demonstrated. Resistin produced by PVAT plays a pivotal role in the up‐regulated expression of OPN in the diabetic vasculature via a signalling pathway that involves activation of AP‐1. © 2013 The Authors. Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain
and Ireland.
Characterisation of glycoproteins using a quadrupole time‐of‐flight mass spectrometer configured for electron transfer dissociation
Authors: Williams Jonathan P. , Pringle Steven , Richardson Keith , Gethings Lee , Vissers Johannes P. C. , De Cecco Martin , Houel Stephane , Chakraborty Asish B. , Yu Ying Qing , Chen Weibin , Brown Jeffery M. 
Published: October 2013

RATIONALEElectron transfer dissociation (ETD) within ion trapping mass spectrometers has proven to be a useful tool for the characterisation of post‐translational modifications. In this study, we describe the implementation of ETD upon a modified quadrupole time‐of‐flight (Q‐ToF) system and methods for the analysis of glycoproteins.METHODSLiquid chromatography electrospray ionisation mass spectrometry (LC/ESI‐MS) was performed using a hybrid quadrupole/ion mobility/oa‐ToF mass spectrometer equipped with ETD functionality. 1,4‐Dicyanobenzene reagent anions necessary for the ETD reaction were generated from a glow discharge region located within the ESI source block. ETD reactions occurred in the stacked ring travelling wave ion guide (located after the quadrupole mass filter and prior to the oa‐ToF mass analyser). LC/ETD was performed upon 'super‐charged' tryptic glycopeptide ions produced from the recombinant monoclonal antibody trastuzumab. LC/ETD was also performed on ions from the smaller glycopeptides obtained from erythropoietin.RESULTSETD performed upon the quadruply 'super‐charged' N‐linked glycopeptide ions of trastuzumab and the triply charged O‐linked glycopeptide ions of erythropoietin provided both glycosylation site assignments and full sequence information, respectively. Tandem mass (MS/MS) spectra employing collision‐induced dissociation (CID) were dominated by oxonium product ions hampering full peptide sequence characterisation.CONCLUSIONSLC/ETD on the Q‐ToF system proved effective at characterising a number of different N‐linked glyco‐forms of the tryptic peptide, EEQYNSTYR, from trastuzumab as well as glyco‐forms from the O‐linked tryptic peptide, EASIPPDAASAAPLR, from erythropoietin. The data demonstrates that the glycopeptide site heterogeneity of trastuzumab and erythropoietin can be accurately characterised. In addition, the post‐column mixing of the super‐charging reagent, m‐NBA, is an effective method to increase the precursor ion charge state and to improve ETD reaction efficiency. Copyright © 2013 John Wiley & Sons, Ltd.
Ozonation degrades all detectable organic compound classes in oil sands process‐affected water; an application of high‐performance liquid chromatography/obitrap mass spectrometry
Authors: Pereira Alberto S. , Islam MD Shahinoor , Gamal El‐Din Mohamed , Martin Jonathan W. 
Published: October 2013

RATIONALESurface mining of bitumen in Northern Alberta, Canada, results in large volumes of toxic oil sands process‐affected water (OSPW) that must be contained in tailings ponds. Ozonation has shown great promise as an OSPW treatment process, by decreasing its toxicity and increasing its biodegradability, but the effect of ozonation on the thousands of dissolved organic chemical groups has not yet been examined.METHODSReversed‐phase liquid chromatography with ultrahigh‐resolution linear ion trap‐orbitrap mass spectrometry was applied to the characterization of treated (utilized ozone doses of 20 and 50 mg O3/L) and untreated OSPW. The analysis was performed in positive and negative electrospray ionization modes for each sample (ESI+/ESI–).RESULTSSemi‐quantitative analysis of ozonated and unozonated samples allowed degradation to be monitored for naphthenic acids (i.e. O2 species in ESI– mode) and >2000 other organic species belonging to various heteroatom‐containing classes: Ox (where x = 1 to 6), NOx (where x = 1 to 4), SOx (where x = 1 to 4), NO2S, N, and S. No chlorinated byproducts were detected in any treated sample, but at the low dose (20 mg O3/L) some compound classes increased in abundance (e.g. the O5 class), indicating that they were formed as byproducts at faster rates than they were degraded. Nevertheless, all organic compound classes subsequently diminished at the higher dose (50 mg O3/L). For several Ox and SOx classes, species observed in ESI+ mode (e.g. O2+ species) were often more recalcitrant to ozonation than the corresponding species detected in ESI– mode (e.g. O2– species; naphthenic acids).CONCLUSIONSOzonation appears to be a very suitable treatment option for OSPW, but the more recalcitrant groups of compounds may help to explain the residual toxicity of ozonated OSPW. Analysis of OSPW constituents in both ionization modes is warranted in all future OSPW fate studies. Copyright © 2013 John Wiley & Sons, Ltd.
Complementary mass spectrometric approaches and scanning electron microscopy to study the structural stability of polyurethane tunneled dialysis catheters after exposure to ethanol solutions
Authors: Msakni Nizar , Galmier Marie‐Josèphe , Couret Marie‐Joëlle , Szczepaniak Claire , Bouchon Bernadette , Souweine Bertrand , Lartigue Claire 
Published: October 2013

RATIONALEEthanol lock is an emerging therapeutic option for preventing and/or controlling catheter‐associated infection. A previous study of silicone catheters showed they underwent no polymer degradation when kept in 60% ethanol for 15 days at 37 °C. The stability of the more widely used polyurethane catheters was studied here in the same way.METHODSA qualitative and quantitative study of the stability of Carbothane® catheters was performed following their immersion at 37 °C in different solvents (0.9% sodium chloride as control medium and 40%, 60%, 95% ethanol solutions) for different periods of time (from 5 min to 15 days) using scanning electron microscopy and complementary mass spectrometry techniques.RESULTSElectron ionization analysis of the 95% ethanol storage solutions revealed the release of about 45 products (8 of which were major) subdivided into two groups according to their fragmentation patterns. Combining all the mass spectrometric data made it possible to propose structures. Group I (major) originated from the polycarbonate diol component (soft segment) and group II (minor) from the dicyclohexylmethane‐4,4′‐diisocyanate component (rigid segment). Semi‐quantitative gas chromatography/mass spectrometry (GC/MS) analysis showed that no significantly higher release was observed after immersion for 30 min at 37 °C in 40% ethanol (mean ratio = 0.677 ± 0.068) than after immersion in reference 0.9% sodium chloride solution for 15 days (0.837 ± 0.127).CONCLUSIONSA 30 min‐40% (v/v) ethanol solution can be considered as safe for preventing the infectious complications of Carbothane® dialysis catheters, and a 30 min‐60% (v/v) ethanol treatment can be occasionally used to eradicate established biofilm. Copyright © 2013 John Wiley & Sons, Ltd.
Recombinant " IMS TAG" proteins – A new method for validating bottom‐up matrix‐assisted laser desorption/ionisation ion mobility separation mass spectrometry imaging
Authors: Cole Laura M. , Mahmoud Khaled , Haywood‐Small Sarah , Tozer Gillian M. , Smith David P. , Clench Malcolm R. 
Published: October 2013

RATIONALEMatrix‐assisted laser desorption/ionisation mass spectrometry imaging (MALDI‐MSI) provides a methodology to map the distribution of peptides generated by in situ tryptic digestion of biological tissue. It is challenging to correlate these peptides to the proteins from which they arise because of the many potentially overlapping and hence interfering peptide signals generated.METHODSA recombinant protein has been synthesised that when cleaved with trypsin yields a range of peptide standards for use as identification and quantification markers for multiple proteins in one MALDI‐IMS‐MSI experiment. Mass spectrometry images of the distribution of proteins in fresh frozen and formalin‐fixed paraffin‐embedded tissue samples following in situ tryptic digestion were generated by isolating signals on the basis of their m/z value and ion mobility drift time, which were correlated to matching peptides in the recombinant standard.RESULTSTryptic digestion of the IMS‐TAG protein and MALDI‐MS analysis yielded m/z values and ion mobility drift time for the signature peptides included in it. MALDI‐IMS‐MSI images for the distribution of the proteins HSP90 and vimentin, in FFPE EMT6 mouse tumours, and HSP90 and plectin in a fresh frozen mouse fibrosarcoma, were generated by extracting ion images at the corresponding m/z value and drift time from the tissue samples.CONCLUSIONSThe IMS‐TAG approach provides a new means to confirm the identity of peptides generated by in situ digestion of biological tissue. Copyright © 2013 John Wiley & Sons, Ltd.
High‐precision measurement of phenylalanine δ15N values for environmental samples: A new approach coupling high‐pressure liquid chromatography purification and elemental analyzer isotope ratio mass spectrometry
Authors: Broek Taylor A. B. , Walker Brett D. , Andreasen Dyke H. , McCarthy Matthew D. 
Published: October 2013

RATIONALECompound‐specific isotope analysis of individual amino acids (CSI‐AA) is a powerful new tool for tracing nitrogen (N) source and transformation in biogeochemical cycles. Specifically, the δ15N value of phenylalanine (δ15NPhe) represents an increasingly used proxy for source δ15N signatures, with particular promise for paleoceanographic applications. However, current derivatization/gas chromatography methods require expensive and relatively uncommon instrumentation, and have relatively low precision, making many potential applications impractical.METHODSA new offline approach has been developed for high‐precision δ15N measurements of amino acids (δ15NAA), optimized for δ15NPhe values. Amino acids (AAs) are first purified via high‐pressure liquid chromatography (HPLC), using a mixed‐phase column and automated fraction collection. The δ15N values are determined via offline elemental analyzer‐isotope ratio mass spectrometry (EA‐IRMS).RESULTSThe combined HPLC/EA‐IRMS method separated most protein AAs with sufficient resolution to obtain accurate δ15N values, despite significant intra‐peak isotopic fractionation. For δ15NPhe values, the precision was ±0.16‰ for standards, 4× better than gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS; ±0.64‰). We also compared a δ15NPhe paleo‐record from a deep‐sea bamboo coral from Monterey Bay, CA, USA, using our method versus GC/C/IRMS. The two methods produced equivalent δ15NPhe values within error; however, the δ15NPhe values from HPLC/EA‐IRMS had approximately twice the precision of GC/C/IRMS (average stdev of 0.27‰ ± 0.14‰ vs 0.60‰ ± 0.20‰, respectively).CONCLUSIONSThese results demonstrate that offline HPLC represents a viable alternative to traditional GC/C/IMRS for δ15NAA measurement. HPLC/EA‐IRMS is more precise and widely available, and therefore useful in applications requiring increased precision for data interpretation (e.g. δ15N paleoproxies). Copyright © 2013 John Wiley & Sons, Ltd.
Analysis of oxygen‐17 excess of nitrate and sulfate at sub‐micromole levels using the pyrolysis method
Authors: Geng Lei , Schauer Andrew J. , Kunasek Shelley A. , Sofen Eric D. , Erbland Joseph , Savarino Joël , Allman Daniel J. , Sletten Ronald S. , Alexander Becky 
Published: October 2013

RATIONALEThe oxygen‐17 excess (Δ17O) of nitrate and sulfate contains valuable information regarding their atmospheric formation pathways. However, the current pyrolysis method to measure Δ17O requires large sample amounts (>4 µmol for nitrate and >1 µmol for sulfate). We present a new approach employing a Gas Bench interface which cryofocuses O2 produced from sample pyrolysis, enabling the analysis of sub‐micromole size samples.METHODSSilver nitrate or sulfate at sub‐micromole levels in a sample container was thermally decomposed to O2 and byproducts in a modified Temperature Conversion/Elemental Analyzer (TC/EA). Byproducts (mainly NO2 for silver nitrate and SO2 for silver sulfate) were removed in a liquid nitrogen trap and the sample O2 was carried by ultra‐pure helium (He) gas to a Gas Bench II interface where it was cryofocused prior to entering an isotope ratio mass spectrometer.RESULTSAnalysis of the international nitrate reference material USGS35 (Δ17O = 21.6‰) within the size range of 300–1000 nmol O2 gave a mean Δ17O value of (21.6 ± 0.69) ‰ (mean ±1σ). Three inter‐laboratory calibrated sulfate reference materials, Sulf‐α, Sulf‐β and Sulf‐ε, each within the size range of 180–1000 nmol O2, were analyzed and shown to possess mean Δ17O values of (0.9 ± 0.10) ‰, (2.1 ± 0.25) ‰ and (7.0 ± 0.63) ‰, respectively.CONCLUSIONSThe analyses of nitrate and sulfate reference materials at sub‐micromole levels gave Δ17O values consistent with their accepted values. This new approach of employing the Gas Bench to cryofocus O2 after the pyrolysis of AgNO3 and Ag2SO4 particularly benefits the effort of measuring Δ17O in sample types with a low abundance of nitrate and sulfate such as ice cores. Copyright © 2013 John Wiley & Sons, Ltd.
A membrane inlet mass spectrometry system for noble gases at natural abundances in gas and water samples
Authors: Visser Ate , Singleton Michael J. , Hillegonds Darren J. , Velsko Carol A. , Moran Jean E. , Esser Bradley K. 
Published: October 2013

RATIONALENoble gases dissolved in groundwater can reveal paleotemperatures, recharge conditions, and precise travel times. The collection and analysis of noble gas samples are cumbersome, involving noble gas purification, cryogenic separation and static mass spectrometry. A quicker and more efficient sample analysis method is required for introduced tracer studies and laboratory experiments.METHODSA Noble Gas Membrane Inlet Mass Spectrometry (NG‐MIMS) system was developed to measure noble gases at natural abundances in gas and water samples. The NG‐MIMS system consists of a membrane inlet, a dry‐ice water trap, a carbon‐dioxide trap, two getters, a gate valve, a turbomolecular pump and a quadrupole mass spectrometer equipped with an electron multiplier. Noble gases isotopes 4He, 22Ne, 38Ar, 84Kr and 132Xe are measured every 10 s.RESULTSThe NG‐MIMS system can reproduce measurements made on a traditional noble gas mass spectrometer system with precisions of 2%, 8%, 1%, 1% and 3% for He, Ne, Ar, Kr and Xe, respectively. Noble gas concentrations measured in an artificial recharge pond were used to monitor an introduced xenon tracer and to reconstruct temperature variations to within 2 °C. Additional experiments demonstrated the capability to measure noble gases in gas and in water samples, in real time.CONCLUSIONSThe NG‐MIMS system is capable of providing analyses sufficiently accurate and precise for introduced noble gas tracers at managed aquifer recharge facilities, groundwater fingerprinting based on excess air and noble gas recharge temperature, and field and laboratory studies investigating ebullition and diffusive exchange. Copyright © 2013 John Wiley & Sons, Ltd.
Comprehensive analysis of neurotransmitters from regenerating planarian extract using an ultrahigh‐performance liquid chromatography/mass spectrometry/selected reaction monitoring method
Authors: Rangiah Kannan , Palakodeti Dasaradhi 
Published: October 2013

RATIONALEAbsolute quantification of neurotransmitters (NTs) from biological systems is imperative to track how changes in concentration of active neurochemicals may affect biological behavior. A sensitive method for the absolute quantification of multiple NTs in a single method is highly needed.METHODSA stable‐isotope dilution ultrahigh‐performance liquid chromatography/mass spectrometry/selected reaction monitoring (UHPLC/MS/SRM) assay has been developed for a sensitive and quantitative assessment of NTs in planaria. We used this method for the simultaneous quantification of 16 NTs. All analytes showed a linear relationship between concentrations (0.78–50 ng/mL), regression coefficients higher than 0.97, accuracy (91–109%) and low coefficients of variation (CVs). The inter‐day CVs for the lowest quality controls (1.56 ng/mL) were in the range between 2–11%.RESULTSThe levels of most of the NTs were similar in both sexual and asexual planarians except for glutamic acid, which was about two‐fold higher in asexual compared to sexual planarians. We identified high levels of serotonin and failed to detect tryptamine suggesting that the pathway essential for the conversion of tryptophan into tryptamine is absent in planarians. Interestingly, we also found high levels of dopamine and L‐DOPA in regenerating planarians suggesting their possible role in regeneration.CONCLUSIONSFor the first time, we developed novel methodology based on UHPLC/MS/SRM and quantified 16 NTs with high sensitivity and specificity from sexual and asexual strains of planarian Schmidtea mediterranea. This method will also have great application in quantifying various NTs with great precision in different model systems. Copyright © 2013 John Wiley & Sons, Ltd.
A novel Cookson‐type reagent for enhancing sensitivity and specificity in assessment of infant vitamin D status using liquid chromatography/tandem mass spectrometry
Authors: Ogawa Shoujiro , Ooki Satoshi , Morohashi Misato , Yamagata Kenichiro , Higashi Tatsuya 
Published: October 2013

RATIONALE25‐Hydroxyvitamin D3 [25(OH)D3] is the best‐established indicator of vitamin D status. 4‐Phenyl‐1,2,4‐triazoline‐3,5‐dione (PTAD), a representative Cookson‐type reagent, has often been employed for enhancing the sensitivity in the trace determination of 25(OH)D3 in a neonatal dried blood spot (DBS), which contains only 2.65 μL of whole blood, using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS). The objective of this study was the development of a novel Cookson‐type reagent surpassing PTAD in terms of sensitivity and specificity in the LC/ESI‐MS/MS assay of 25(OH)D3.METHODSA novel Cookson‐type reagent, 4‐(4'‐dimethylaminophenyl)‐1,2,4‐triazoline‐3,5‐dione (DAPTAD), was synthesized from 4‐dimethylaminobenzoyl chloride. The DAPTAD‐derivative of 25(OH)D3 was prepared and its LC/ESI‐MS/MS behavior was examined. The applicability of the DAPTAD‐derivatization in the determination of 25(OH)D3 in neonatal DBSs was also examined.RESULTSThe derivatization was completed at room temperature within 1 h. The DAPTAD‐derivative of 25(OH)D3 provided a characteristic product ion derived from the cleavage of the vitamin D skeleton during MS/MS. The limit of detection of the DAPTAD‐derivative during selected reaction monitoring was 0.25 fmol on the column, which was 30 and 2 times lower than those of the intact 25(OH)D3 and the PTAD‐derivative, respectively. The DAPTAD‐derivatization followed by LC/ESI‐MS/MS enabled the detection of a trace amount (in the low‐ng/mL range) of 25(OH)D3 in DBSs with a simple pretreatment (only methanol extraction) and short chromatographic run time (10 min). The DAPTAD‐derivatization was also useful for the separation of 25(OH)D3 from a potent interfering metabolite, 3‐epi‐25‐hydroxyvitamin D3 [3‐epi‐25(OH)D3]. On the contrary, the assay using the PTAD‐derivatization might lead to overestimation of the true 25(OH)D3 levels due to the co‐elution of 25(OH)D3 and 3‐epi‐25(OH)D3.CONCLUSIONSWe developed DAPTAD for enhancing the sensitivity and specificity of the LC/ESI‐MS/MS assay of 25(OH)D3. Our new method using DAPTAD can reduce the overestimation of the 25(OH)D3 levels, and will prove helpful in the diagnosis of vitamin D deficiency in infants. Copyright © 2013 John Wiley & Sons, Ltd.