bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polypentadecalactone prepared by lipase catalysis: crystallization kinetics and morphology
Authors: Cai Jiali , Hsiao Benjamin S , Gross Richard A 
Published: June 2009

AbstractBACKGROUND: This work addresses the need to better understand the crystallization kinetics and morphology of poly (ω‐pentadecalactone) (PPDL). This polyester has promising mechanical properties and a unique structure that resembles that of polyethylene. PPDL is a member of the poly(ω‐hydroxy fatty acid) family, which can be derived from biobased feedstocks.RESULTS: PPDL (Mn = 34 000 g mol−1 and dispersity D = Mw/Mn = 2.7) was synthesized using enzyme catalysis. Equilibrium melting enthalpy and equilibrium melting point were determined using extrapolation techniques, being 227 J g−1 and 101 °C, respectively. In addition, the equilibrium melting point ($T_{\rm {m}}^{0}$) was found to be 109.3 °C by the nonlinear Hoffman‐Weeks plot. For $T_{\rm {m}}^{0} = 101.0 ^{\circ}\hbox{C}$, the lateral surface free energy (σ), fold surface free energy (σe) and fold work (q) are 10.4 erg cm−2, 47.5 erg cm−2 and 2.6 kcal mol−1, respectively; while for $T_{\rm {m}}^{0} = 109.3 ^{\circ}\hbox{C}$, they are 25.1 erg cm−2, 46.6 erg cm−2 and 2.6 kcal mol−1, respectively. The results indicated the existence of a regime I to regime II transition during crystallization at about 80 °C. Polarized optical microscopy and AFM provided further evidence for the regime I–II transition. In regime I, coarse spherulites were formed through splaying out and occasional branching of lamellae, as well as stacking of lamellae through screw dislocation. In contrast, in regime II, banded spherulites were formed through crystal twisting.CONCLUSION: Morphological changes in PPDL at spherulitic and lamellar levels in regimes I and II were confirmed by differential scanning calorimetry, POM and AFM. Copyright © 2009 Society of Chemical Industry
Analysis of novel over‐ and under‐sulfated glycosaminoglycan sequences by enzyme cleavage and multiple stage MS
Authors: Zamfir Alina D. , Flangea Corina , Sisu Eugen , Serb Alina F. , Dinca Nicolae , Bruckner Peter , Seidler Daniela G. 
Published: June 2009

AbstractWe report on a novel strategy for identification of specific sulfation motifs in chondroitin/dermatan sulfate (CS/DS) chain derived from decorin (Dcn), based on enzyme cleavage and multistage MS (MSn). Released CS/DS chains were digested with chondroitin B and in parallel with AC I lyases to obtain oligosaccharides of known hexuronic acid (HexA) epimerization. The depolymerized chains were separated by gel filtration, and collected di‐ and hexasaccharides were analyzed by ESI MSn. MS2 on bisulfated 4,5‐Δ‐HexAGalNAc revealed an additional sulfate ester group at 4,5‐Δ‐HexA. MS2 data provided evidence upon GlcA sulfation in Dcn due to the fact that 4,5‐Δ‐HexA derived from GlcA after chondroitin AC I lyase treatment. Hexasaccharide screening in the MS1 mode indicated direct correlation between the sulfate distribution and HexA epimerization. MSn performed on ions that, according to mass calculation, correspond to pentasulfated [4,5‐Δ‐HexAGalNAc(GlcAGalNAc)2], trisulfated [4,5‐Δ‐HexAGalNAc(GlcAGalNAc)2] with IdoA‐derived 4,5‐Δ‐HexA at the nonreducing end, tetrasulfated [4,5‐Δ‐HexAGalNAc(IdoAGalNAc)2] and monosulfated [4,5‐Δ‐HexAGalNAc(IdoAGalNAc)2] with GlcA‐derived 4,5‐Δ‐HexA at the nonreducing end rendered fragmentation patterns confirming the presence of over‐, regular, and under‐sulfated regions as well as structural motifs having both types of HexA sulfated within Dcn CS/DS.
Fire protection sprinkler system for extremely corrosive industrial duct environments
Authors: Su Paul , Doerr William W. 
Published: June 2009

AbstractBecause of the extremely corrosive environments inside many industrial exhaust ducts, sprinkler systems have not been successfully designed to protect against fires originating within these ducts. Damage to the exhaust ductwork system caused by fire can lead to interruption of the plant operations for an extended period of time with substantial financial losses. Research has been performed to evaluate the corrosion resistance properties of various materials and coatings such that corrosion resistant sprinklers and fire protection hardware can be developed for use in these flammable exhaust ducts and other corrosive industrial environments. Laboratory tests, including electrochemical techniques and crevice coupon immersion tests, were used to select suitable alloys and coatings for in‐situ field test rack studies. These results are providing the basis for the development of fire protection systems suitable for these industrial exhaust ducts.1 © 2009 American Institute of Chemical Engineers Process Saf Prog 2010
Dysmenorrhoea: a practical evidence‐based approach
Authors: Monaghan Marie , Islam Melissa , Varma Rajesh 
Published: June 2009

AbstractDysmenorrhoea is a common condition that can adversely affect a woman's quality of life. Our Drug review describes how to distinguish primary from secondary dysmenorrhoea and assesses the evidence for the various treatment options. Copyright © 2009 Wiley Interface Ltd
Inversion layer electron transport in 4H‐SiC metal–oxide–semiconductor field‐effect transistors
Authors: Tilak Vinayak 
Published: June 2009

AbstractSilicon carbide is the only compound semiconductor with silicon dioxide as its native oxide and can form metal–oxide–semiconductor field‐effect transistors. In this article, we review the inversion layer electron transport properties of 4H‐SiC/SiO2. The inversion layer electron transport theories developed for the Si/SiO2 system have been reviewed to highlight the behaviour of inversion layer electrons at an ideal interface. The 4H‐SiC/SiO2 interface, is currently far from ideal and so we discuss the inversion layer electron transport for several techniques of oxidation of the (0001) 4H‐SiC including nitridation of thermal oxides and sodium enhanced oxidation of 4H‐SiC. Inversion layer mobility of nitrided oxides is dominated by Coulomb scattering at low surface electric field values and surface roughness scattering at high surface electric field values. In sodium enhanced oxidation samples no trapped charge is found at the interface close to the conduction band edge, but the temperature dependence of mobility shows that the samples are not limited by phonon scattering and therefore not ideal. We also review the results of inversion layer transport on alternate faces of 4H‐SiC. We conclude highlighting the future work remaining in the field and the behaviour of inversion layer electron mobility we expect to see in an ideal 4H‐SiC/SiO2 interface. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Two alternative implementations of the ensemble‐transform (ET) analysis‐perturbation scheme: The ET with extended cycling intervals, and the ET without cycling
Authors: McLay Justin , Reynolds Carolyn A. 
Published: June 2009

AbstractFour alternative approximate bases for the ensemble transform (ET) are obtained by extending the cycling interval to 24, 48, 72 and 96 h. Another alternative basis is obtained by foregoing cycling and instead drawing randomly generated perturbations from an archive. Experiments based upon 16‐member global ensembles and a diagonal estimate of analysis‐error covariance indicate that the alternative bases are effective at reducing the discrepancy between the ET analysis‐perturbation variance and the estimated analysis‐error variance. Forecast ensembles associated with the alternative bases maintain considerably more energy in the tropics and subtropics than the forecast ensemble associated with the original basis. Forecast ensembles associated with the alternative bases also outperform the original forecast ensemble in terms of the ensemble forecast‐error covariance‐matrix eigenvalue spectrum, the relationship between ensemble variance and observed squared error and the Brier score. The performance gains facilitated by the alternative approximate bases are substantial in some instances, especially in the tropics. The randomly sampled basis is superior to the original basis in most respects. Published in 2009 by John Wiley & Sons, Ltd.
Covariance regularization in inverse space
Authors: Ueno Genta , Tsuchiya Takashi 
Published: June 2009

AbstractIn data assimilation, covariance matrices are introduced in order to prescribe the weights of the initial state, model dynamics, and observation, and suitable specification of the covariances is known to be essential for obtaining sensible state estimates. The covariance matrices are specified by sample covariances and are converted according to an assumed covariance structure. Modelling of the covariance structure consists of the regularization of a sample covariance and the constraint of a dynamic relationship. Regularization is required for converting the singular sample covariance into a non‐singular sample covariance, removing spurious correlation between variables at distant points, and reducing the required number of parameters that specify the covariances. In previous studies, regularization of sample covariances has been carried out in physical (grid) space, spectral space, and wavelet space. We herein propose a method for covariance regularization in inverse space, in which we use the covariance selection model (the Gaussian graphical model). For each variable, we assume neighbouring variables, i.e. a targeted variable is directly related to its neighbours and is conditionally independent of the non‐neighbouring variables. Conditional independence is expressed by specifying zero elements in the inverse covariance matrix. The non‐zero elements are estimated numerically by the maximum likelihood using Newton's method. Appropriate neighbours can be selected with the AIC or BIC information criteria. We address some techniques for implementation when the covariance matrix has a large dimension. We present an illustrative example using a simple 3 × 3 matrix and an application to a sample covariance obtained from sea‐surface height observations. Copyright © 2009 Royal Meteorological Society
Temperature‐dependent release of volatile organic compounds of eucalypts by direct analysis in real time (DART) mass spectrometry
Authors: Maleknia Simin D. , Vail Teresa M. , Cody Robert B. , Sparkman David O. , Bell Tina L. , Adams Mark A. 
Published: June 2009

AbstractA method is described for the rapid identification of biogenic, volatile organic compounds (VOCs) emitted by plants, including the analysis of the temperature dependence of those emissions. Direct analysis in real time (DART) enabled ionization of VOCs from stem and leaf of several eucalyptus species including E. cinerea, E. citriodora, E. nicholii and E. sideroxylon. Plant tissues were placed directly in the gap between the DART ionization source skimmer and the capillary inlet of the time‐of‐flight (TOF) mass spectrometer. Temperature‐dependent emission of VOCs was achieved by adjusting the temperature of the helium gas into the DART ionization source at 50, 100, 200 and 300°C, which enabled direct evaporation of compounds, up to the onset of pyrolysis of plant fibres (i.e. cellulose and lignin). Accurate mass measurements facilitated by TOF mass spectrometry provided elemental compositions for the VOCs. A wide range of compounds was detected from simple organic compounds (i.e. methanol and acetone) to a series of monoterpenes (i.e. pinene, camphene, cymene, eucalyptol) common to many plant species, as well as several less abundant sesquiterpenes and flavonoids (i.e. naringenin, spathulenol, eucalyptin) with antioxidant and antimicrobial properties. The leaf and stem tissues for all four eucalypt species showed similar compounds. The relative abundances of methanol and ethanol were greater in stem wood than in leaf tissue suggesting that DART could be used to investigate the tissue‐specific transport and emissions of VOCs. Copyright © 2009 John Wiley & Sons, Ltd.
Semi‐quantitative and structural metabolic phenotyping by direct infusion ion trap mass spectrometry and its application in genetical metabolomics
Authors: Koulman Albert , Cao Mingshu , Faville Marty , Lane Geoff , Mace Wade , Rasmussen Susanne 
Published: June 2009

AbstractThe identification of quantitative trait loci (QTL) for plant metabolites requires the quantitation of these metabolites across a large range of progeny. We developed a rapid metabolic profiling method using both untargeted and targeted direct infusion tandem mass spectrometry (DIMSMS) with a linear ion trap mass spectrometer yielding sufficient precision and accuracy for the quantification of a large number of metabolites in a high‐throughput environment. The untargeted DIMSMS method uses top‐down data‐dependent fragmentation yielding MS2 and MS3 spectra. We have developed software tools to assess the structural homogeneity of the MS2 and MS3 spectra hence their utility for phenotyping and genetical metabolomics. In addition we used a targeted DIMS(MS) method for rapid quantitation of specific compounds. This method was compared with targeted LC/MS/MS methods for these compounds. The DIMSMS methods showed sufficient precision and accuracy for QTL discovery. We phenotyped 200 individual Lolium perenne genotypes from a mapping population harvested in two consecutive years. Computational and statistical analyses identified 246 nominal m/z bins with sufficient precision and homogeneity for QTL discovery. Comparison of the data for specific metabolites obtained by DIMSMS with the results from targeted LC/MS/MS analysis showed that quantitation by this metabolic profiling method is reasonably accurate. Of the top 100 MS1 bins, 22 ions gave one or more reproducible QTL across the 2 years. Copyright © 2009 John Wiley & Sons, Ltd.
Long term outcome of organic acidurias: Survey of 105 French cases (1967–1983)
Authors: Rousson R. , Guibaud P. 
Published: June 2009

AbstractThe French experience in the long term follow‐up of 105 cases of organic aciduria (45 maple syrup urine disease, 12 isovaleric acidaemia, 19 propionic acidaemia, 24 methylmalonic aciduria and some rare allied disorders) is reported. Main conclusions drawn from this survey are the poor overall prognosis and the slow improvement in the outcome of such disorders over the last 15 years. In MSUD, while early diagnosis and early management remain a basic requirement, intellectual development did not improve as much as expected. In propionic and methylmalonic acidaemia modern treatment does not prevent a fatal outcome in the classical neonatal forms. It should be also emphasized that in the rare cases where a coenzyme deficiency has been demonstrated, vitamin therapy is very often ineffectivein vivo.
The management and long term outcome of organic acidaemias
Authors: Leonard J. V. , Daish P. , Naughten E. R. , Bartlett K. 
Published: June 2009

AbstractWe review the outcome of patients with maple syrup urine disease (14 classical patients and three variants), biotinidase deficiency (two patients) and non‐cofactor‐responsive variants of methylmalonic acidaemia (eight patients), propionic acidaemia (eight patients) and isolated 3‐methylcrotonyl CoA carboxylase deficiency (three patients). Their survival, growth, intellectual development and other clinical problems are analysed. With the exception of isolated 3‐methylcrotonyl CoA carboxylase deficiency the outcome of patients with disorders that are not cofactor responsive is disappointing. Twelve patients have died (five maple syrup urine disease, two methylmalonic acidaemia, five propionic acidaemia) and many of the survivors are developmentally retarded. The outlook is worst for patients with propionic acidaemia presenting in the neonatal period but a good outcome is possible for patients with maple syrup urine disease if the diagnosis is made early.
Glutaric acidaemia type II (multiple Acyl‐Coa dehydrogenation deficiency)
Authors: Goodman S. I. , Frerman F. E. 
Published: June 2009

AbstractThe clinical and biochemical phenotype of glutaric acidaemia type II (GAII) has led to the suggestion that the defect in the disorder affects electron transfer from primary FAD‐containing dehydrogenases into the respiratory chain. Two proteins are involved in this process, i.e. electron transfer flavoprotein (ETF) and ETF dehydrogenase, an iron‐sulphur flavoprotein with a distinctive EPR signal. Reliable catalytic assays for these proteins are not available, but both proteins have been purified and antisera against them prepared in rabbits.SDS‐PAG electrophoresis of liver mitochondrial membranes from a GAII infant with congenital anomalies, locating ETF dehydrogenase with specific antiserum, showed no cross‐reactive material. EPR of the same membranes showed a marked decrease in the ETF dehydrogenase signal. These results suggest that the defect in GAII in some patients is indeed in electron transport, and specifically in ETF dehydrogenase.
The differential diagnosis of dicarboxylic aciduria
Authors: Duran M. , De Klerk J. B. C. , Wadman S. K. , Bruinvis L. , Ketting D. 
Published: June 2009

AbstractVarious types of dicarboxylic aciduria are known, most of them are accompanied by non‐ketotic hypoglycaemia. For the differential diagnosis of these conditions several methods of investigation have been used: (1) analysis of urinary organic acids in both native and hydrolysed samples, (2) analysis of free and esterified carnitine, the latter by means of chromatographic separation and identification of acyl moieties, (3) analysis of plasma organic acids, including the so‐called free fatty acids, (4) a prolonged fasting test with serial measurements of the aforementioned parameters and close monitoring of the blood glucose and (5) an oral loading test with medium chain triglycerides accompanied by the same measurements as those named in item (4).So far differentiation has been made between patients with a metabolite profile most probably characteristic of medium chain acyl‐CoA dehydrogenase deficiency and other dicarboxylic acidurias, among the latter systemic carnitine deficiency. Patients belonging to the first group accumulate octanoate, decanoate andcis‐4‐decenoate in their plasma; they excrete hexanoylglycine, octanoylcarnitine and suberylglycine in addition to the usual C6–C10 dicarboxylic acids. There was a high prevalence of an increased plasma free fatty acid/3‐hydroxybutyrate ratio.
Mitochondrial myopathies: Disorders of the respiratory chain and oxidative phosphorylation
Authors: Clark J. B. , Hayes D. J. , Morgan‐Hughes J. A. , Byrne E. 
Published: June 2009

AbstractMitochondrial myopathies are a clinical condition characterized by muscle weakness and fatigue in which the primary defect is localized at the level of the mitochondria. Microscopic examination shows accumulations of mitochondria at the fibre periphery (ragged red fibres) and in some cases mitochondrial paracrystalline inclusions. The spectrum of different mitochondrial defects so far described is reviewed and data from cases investigated in this laboratory are described. The first case was a 17‐year‐old boy with a multisystem disorder whose muscle mitochondria showed low respiratory activity with all substrates, which doubled in the presence of uncouples Further investigation showed that the mitochondrial ATPase activity was only 6 % of normal. The next cases were a mother and daughter who showed a typical lipid storage myopathy. The latter was treated successfully with oral carnitine but the myopathy persisted. Mitochondrial investigations indicated a low respiratory activity with NAD‐linked substrates but normal activity with succinate and ascorbate + TMPD. A defect in the NADH‐CoQ reductase section of the respiratory chain was pinpointed possibly at an iron‐sulphur centre. The fourth and fifth cases were two sisters who exhibited no lipid storage myopathy but whose mitochondrial activity was low with NAD‐linked substrates but normal with succinate. Again a defect in the NADH‐CoQ reductase (complex I) of the respiratory chain was determined. They were also investigated using31P‐NMR. It was found after exercise that their muscle creatine phosphate levels took seven times longer to return to pre‐exercise concentrations than control subjects.These results are discussed with respect to the synthesis of mitochondrial proteins and the influence that both the mitochondrial and nuclear DNA have on this process.
Organic acids in urine of patients with congenital lactic acidoses: An aid to differential diagnosis
Authors: Chalmers R. A. 
Published: June 2009

AbstractThe differential diagnosis of patients with apparent congenital lactic acidoses poses one of the most intractable problems in the study of patients with disorders of organic acid metabolism. An outline of the factors leading to a lactic acidosis, particularly in infants and young children, together with a brief review of the known causes of congenital lactic acidosis, are presented. Quantitative examination of the organic acids excreted by patients with proven enzyme deficiencies causing congenital lactic acidosis has demonstrated the characteristic patterns that are associated with specific disorders of this kind. After exclusion of uninherited, acquired and secondary metabolic causes of lactic acidosis, these quantitative patterns of organic acid excretion, together with other clinical and biochemical observations, provide valuable indicators of the area of the underlying primary metabolic disorder for subsequent selected, confirmatory, enzymology. The study of organic acids has a key and central role in the approach to the clinical and biochemical investigation and diagnosis of patients with congenital lactic acidoses.
A Comprehensive Evaluation of the Melting Points of Fatty Acids and Esters Determined by Differential Scanning Calorimetry
Authors: Knothe Gerhard , Dunn Robert O. 
Published: June 2009

AbstractThe melting point is one of the most important physical properties of a chemical compound and it plays a significant role in determining possible applications. For fatty acid esters the melting point is essential for a variety of food and non‐food applications, the latter including biodiesel and its cold‐flow properties. In this work, the melting points of fatty acids and esters (methyl, ethyl, propyl, butyl) in the C8–C24 range were determined by differential scanning calorimetry (DSC), many of which for the first time. Data for triacylglycerols as well as ricinoleic acid and its methyl and ethyl esters were also acquired. For some compounds whose melting points have been previously reported, data discrepancies exist and a comprehensive determination by DSC has not been available. Variations in the present data up to several °C compared to data in prior literature were observed. The melting points of some methyl‐branched iso‐ and anteiso‐acids and esters were also determined. Previously unreported systematic effects of compound structure on melting point are presented, including those for ω‐9 monounsaturated fatty acids and esters as well as for methyl‐branched iso and anteiso fatty acids and esters. The melting point of a pure fatty acid or ester as determined by DSC can vary up to approximately 1 °C. Other thermal data, including heat flow and melting onset temperatures are briefly discussed.