bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas‐phase positive ion chemistry of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane (halothane) upon electron ionization within an ion trap mass spectrometer
Authors: Marotta Ester , Scorrano Gianfranco , Paradisi Cristina 
Published: May 2005

AbstractThe positive ion chemistry occurring within an ion trap mass spectrometer upon electron ionization of 1‐bromo‐1‐chloro‐2,2,2‐trifluoroethane, the important anaesthetic halothane, has been mapped by means of collision‐induced decomposition and ion/molecule self‐reaction experiments. Ionized halothane (M+.) reacts with neutral halothane to form the ionized olefin [ClBrCCF2]+. via HF elimination. Among the ionic fragments, [M–Br]+ and [M–F]+ react with halothane via chloride abstraction while [M–Cl]+ is unreactive under the same experimental conditions. Substituted methyl cations CHFX+ and CF2X+ (X = F, Cl, Br) undergo halide transfer processes, their reactivity being highest for X = F. Ionized carbenes CXY+ (X,Y = F,F; H,Br; H,Cl; H,F) react with halothane to form CClXY+ and CBrXY+, whereas CF+ inserts into the CCl bond to form CF and CClF. Finally, Br+ and Cl+ react with halothane by charge transfer. Collision‐induced dissociation experiments disclosed interesting rearrangements involved in the dissociations of +CHX‐CF3 ions (X = Br, Cl), which undergo fluorine migration and elimination of CF2, as already observed for +CCl2‐CF3 in a previous investigation. Copyright © 2005 John Wiley & Sons, Ltd.
δ34S measurements on organic materials by continuous flow isotope ratio mass spectrometry
Authors: Yun Misuk , Mayer Bernhard , Taylor Stephen W. 
Published: May 2005

AbstractSulfur (S) isotope ratios of thoroughly dried organic samples were measured by direct thermal decomposition in an elemental analyzer coupled to an isotope ratio mass spectrometer in continuous flow mode (EA‐CF‐IRMS). For organic samples of up to 13 mg weight and with total S contents of more than 10 μg, the reproducibility of the δ34Sorganic values was ±0.4‰ or better. However, the δ34S values of organic samples measured directly by online EA‐CF‐IRMS analysis were between 0.3 and 2.9‰ higher than those determined on BaSO4 precipitates produced by Parr Bomb™ oxidation from the same sample material. Our results suggest that structural oxygen in organic samples influences the oxygen isotope ratios of the SO2 produced from organic samples. Consequently, SO2 generated from organic samples appears to have different 18O/16O ratios than SO2 generated from BaSO4 precipitates and inorganic reference materials, resulting in a deviation from the true δ34S values because of 32S16O18O contributions to mass 66. It was shown that both the amount of structural oxygen in the organic sample, and the difference of the oxygen isotope ratios between organic samples and tank O2, influenced the magnitude of the observed deviation from the true δ34S value after direct EA‐CF‐IRMS analysis of organic samples. Suggestions are made to correct the difference between measured δ34Sorganic and true δ34S values in order to obtain not only reproducible, but also accurate S isotope ratios for organic materials by EA‐CF‐IRMS. Copyright © 2005 John Wiley & Sons, Ltd.
A novel approach to identify plant parasitic nematodes using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Perera Modika R. , Vanstone Vivien A. , Jones Michael G. K. 
Published: May 2005

AbstractPlant parasitic nematodes are difficult to identify because different species are morphologically similar, and this makes their control more difficult. The aim of this work was to develop a rapid, simple method to identify plant parasitic nematodes, based on analysis of protein profiles of nematodes generated by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). Two methods have been used: grinding and direct analysis of intact nematodes. Both methods were standardised using the nematode Anguina tritici (wheat seed‐gall nematode) as a model. Development of the approach involved optimisation of experimental parameters to generate reproducible diagnostic protein profiles for plant parasitic nematodes. With α ‐cyano‐4‐hydroxycinnamic acid (CHCA) as the matrix, the most effective solvent extraction was with 90% acetone. With sinapinic acid (SA) as matrix, 90% ethanol was most effective. When intact nematodes were analysed directly by mixing with the matrix solution, 40 min extraction with CHCA matrix solution generated the best protein profiles. The standardised methods were applied to analyse the seed‐gall nematodes A. tritici and A. funesta and to the root‐knot nematode, Meloidogyne javanica, which infects many horticultural crops. Typical protein profiles and diagnostic peaks were identified for these nematode species and for mixtures of Anguina species. The results provide ‘proof‐of‐concept’ that these nematode species can be identified by protein profiling using MALDI‐TOFMS. This new approach could be extended to identify other plant and non‐plant parasitic nematodes. Copyright © 2005 John Wiley & Sons, Ltd.
Automated accurate mass data processing using a gas chromatograph/time‐of‐flight mass spectrometer in drug discovery
Authors: Petucci Chris , Mallis Larry 
Published: May 2005

AbstractA gas chromatograph/time‐of‐flight (GCT) mass spectrometer, with high mass measurement accuracy to within 5 ppm, has been used for the automated accurate mass analysis of multicomponent mixtures and drug discovery compounds. A multicomponent mixture was analyzed several times over the course of a week to assess the reproducibility and ruggedness of the automated method while operating the GCT in electron ionization mode. For example, the data for 31 radical cations generated via electron ionization was processed using automated software (i.e. OpenLynx™) to provide for mass accuracies less than 5 ppm for nearly 100% of the ions from multiple injection data. Mass accuracies of the radical anions of polyaromatic hydrocarbons generated via negative chemical ionization, and protonated pyridines and quinolines generated via methane chemical ionization, were mainly less than 5 ppm from multiple injection data. In addition, the automated method has been used for the accurate mass analysis of drug discovery compounds. Copyright © 2005 John Wiley & Sons, Ltd.
Photocatalytic degradation of the herbicide isoproturon: characterisation of by‐products by liquid chromatography with electrospray ionisation tandem mass spectrometry
Authors: Amorisco A. , Losito I. , Palmisano F. , Zambonin P. G. 
Published: May 2005

AbstractBy‐products arising from immobilised TiO2‐catalysed photodegradation of the herbicide isoproturon [3‐(4‐isopropylphenyl)‐1,1‐dimethylurea] in aqueous solution under solar radiation were analysed by reversed‐phase liquid chromatography combined with electrospray ionisation ion trap mass spectrometry. Structural information on by‐products, formed at different degradation times, was then obtained from interpretation of the relevant MS/MS spectra. Several species were identified through this approach, and in many cases several isomers were found. As expected, most by‐products resulted from single or multiple hydroxylation (by photo‐generated OH. radicals) of the isoproturon molecule at different positions. However, substitution of some functional groups of the herbicide (isopropyl or methyl) by OH. was also observed. A possible degradation scheme is hypothesised. Copyright © 2005 John Wiley & Sons, Ltd.
Characterization of oligosaccharide moieties of glycopeptides by microwave‐assisted partial acid hydrolysis and mass spectrometry
Authors: Lee Bao‐Shiang , Krishnanchettiar Sangeeth , Lateef Syed Salman , Gupta Shalini 
Published: May 2005

AbstractMicrowave‐assisted partial acid hydrolysis and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry were used to study oligosaccharide structures of glycopeptides. Tryptic N‐glycosylated peptides of horseradish peroxidase, with MH+ ions at m/z 2533, 2612, 3355, 3673, and 5647, were used as test cases. Within a microwave exposure with trifluoroacetic acid of 2 min, partial cleavages of the oligosaccharides of these tryptic N‐glycosylated peptides were observed. The data showed that the most labile group within the oligosaccharides is the fucose (Fuc) residue, and that a majority of the end cleavage products are peptides with one N‐acetylglucosamine (GlcNAc) residue linked to asparagine (Asn). In addition, the glycopeptides with m/z 3355 and 3673 carry an oligosaccharide (Xyl)Man3(Fuc)GlcNAc2, the glycopeptide at m/z 5647 carries two oligosaccharides (Xyl)Man3(Fuc)GlcNAc2, and the glycopeptides at m/z 2612 and 2533 carry (Xyl)Man3GlcNAc2 and (Fuc)GlcNAc, respectively. However, the glycosylation site of the m/z 2612 peptide at Asn286 is partially occupied. This simple and rapid method is particularly useful in identifying glycopeptides and obtaining monosaccharide compositions of glycopeptides. Copyright © 2005 John Wiley & Sons, Ltd.
Short‐term dynamics of slurry‐derived plant and microbial sugars in a temperate grassland soil as assessed by compound‐specificδ13C analyses
Authors: Sauheitl Leopold , Glaser Bruno , Bol Roland 
Published: May 2005

AbstractIn view of recent discussions about climate change and the anthropogenically enhanced greenhouse effect, the aim of this study was to determine the short‐term carbon (C) dynamics in a grassland soil after slurry application. It is known that, depending on cultivation practices, agro‐ecosystems can act either as sources or as sinks for atmospheric CO2. C3 and C4 slurries were applied, differing in their stable C isotope signature, to be able to differentiate between native (soil‐inherent) and fresh (slurry‐applied) C. Samples were taken from 0–2, 2–7.5 and 7.5–15 cm soil depths from 90 days before until 4 weeks after slurry application at various intervals. We carried out compound‐specific stable isotope analysis (CSIA) of plant‐ (arabinose and xylose) and microbial‐derived sugars (fucose and rhamnose). Up to 45% of the applied slurry‐derived xylose was found in the 0–2 cm soil depth within 24 h after slurry application, with this figure decreasing rapidly and then increasing again towards the end of the experiment. Therefore, during the first phase of slurry incorporation, preferentially the soluble part of slurry entered the first 2 cm of soil while, after about 2 weeks, particulate slurry‐derived organic matter was incorporated into the soil. The ratio between plant‐ and microbial‐derived sugars together withδ13C values of individual sugars in the 2–7.5 cm soil depth revealed that the dissipation of sugars from the 0–2 cm soil depth was not only due to leaching, but also was caused by microbial degradation of the fresh C because slurry did not contain significant amounts of rhamnose while theδ13C values of rhamnose became progressively enriched in13C during the experiment. Stable isotope measurements of bulk soil previously only showed significant differences between C4 and C3 plots at 0–2 cm soil depth. The CSIA of the individual sugars was much more sensitive than bulk isotope measurements, revealing significant differences between C4 and C3 plots even at the 2–7.5 cm soil depth during the first phase of the experiment. Additionally, the dynamics of slurry‐derived plant and microbial sugars could be followed specifically. Copyright © 2005 John Wiley & Sons, Ltd.
Giving priority to evidence in science teaching: A first‐year elementary teacher's specialized practices and knowledge
Authors: Avraamidou Lucy , Zembal‐Saul Carla 
Published: May 2005

AbstractThe purpose of this qualitative case study was to examine the nature of a first‐year elementary teacher's specialized practices and knowledge for giving priority to evidence in science teaching and to explore the possible sources from which this knowledge was generated. Data included three audiotaped interviews, six videotaped classroom observations, lesson plans, and samples of students' work. The findings of this study reveal that the teacher gave priority to evidence by frequently engaging students in collecting evidence through observations and investigations, recording and representing evidence, and using that evidence to construct explanations. The findings of this study also illustrate that critical experiences during preparation to teach and specific university coursework acted as sources through which the teacher's specialized knowledge for giving priority to evidence was generated. © 2005 Wiley Periodicals, Inc. J Res Sci Teach 42: 965–986, 2005
Levels of microcystins in two argentinean reservoirs used for water supply and recreation: Differences in the implementation of safe levels
Authors: Conti Ana Laura Ruibal , Guerrero José María , Regueira Jose María 
Published: May 2005

AbstractToxic cyanobacterial blooms are an increasing problem in Argentina. The production of cyanobacterial hepatotoxins (microcystins) and their presence in drinking and recreational waters represent a growing danger to human and animal health. Risk management deals with the probability that a certain exposure to toxins will lead to specific health outcomes. Various model schemes for risk management have been portrayed, most of which have some common elements. These include the need for an information base on which to make decisions. Thus, seasonal variability in the concentrations of total microcystins and cyanobacterial cells was studied in two reservoirs: San Roque and Paso de las Piedras. Both reservoirs are eutrophic water bodies and mainly used to supply drinking water and for recreation. Because San Roque is an important recreational spot, the spatial distribution of microcystins was also investigated. Sampling of the San Roque Reservoir occurred from 1998 to 2000 and of the Paso de las Piedras Reservoir from June to December 2002 (late autumn, winter, and spring). Microcystins were identified by LC‐MS, and their concentrations were measured using the enzyme‐linked immunosorbent assay. These hepatotoxic compounds were detected in all seasons, and even during winter relatively high concentrations were observed. Concentrations in the San Roque Reservoir varied from undetectable to 920 μg/L. On the contrary, in the Paso de las Piedras Reservoir the concentration remained below 1 μg/L, which is the provisional guideline value proposed by the World Health Organization (WHO; Chorus and Bartram, 1999) for microcystin‐LR in drinking water. Comparison of cell number and concentration of total microcystins indicated that the phytoplankton in San Roque Reservoir contained more toxic cyanobacterial strains than did the Paso de las Piedras Reservoir. This indicates that the threshold of 2000 cell/mL proposed by WHO as a alert level should be adjusted: it should be reduced for the San Roque Reservoir, whereas it seems appropriate for the Paso de la Piedras Reservoir. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 263–269, 2005.
Screening for trisomy 21 in monochorionic twins by measurement of fetal nuchal translucency thickness
Authors: Vandecruys H. , Faiola S. , Auer M. , Sebire N. , Nicolaides K. H. 
Published: May 2005

AbstractObjectiveTo determine whether in screening for trisomy 21 by measurement of fetal nuchal translucency (NT) thickness in monochorionic twin pregnancies it is preferable to use the higher, smaller or average NT.MethodsWe retrospectively examined 769 monochorionic twin pregnancies that had undergone NT screening. The selection criteria were that first, in each pregnancy both fetuses were alive at the 11 to 13 + 6‐week scan and second, the fetal karyotype had been determined by prenatal invasive testing or the pregnancy outcome was known. In each pregnancy the risk for trisomy 21 was calculated by a combination of maternal age and fetal NT for crown–rump length (CRL). Three estimates of risk for each pregnancy were made using the higher, smaller and average NT and these were compared for detection and false positive rates.ResultsThe median maternal age was 33 (range, 16–45) years, the CRL was 62 (range, 45–84) mm and gestational age was 12 (range, 11 to 13 + 6) weeks. Either the fetal karyotype was normal, or phenotypically normal babies were born, in 761 cases. The karyotype was abnormal in eight cases, including six with trisomy 21. The estimated risk using the higher, smaller and average NT was 1 in 300 or more in 6 (100%), 4 (66.7%) and 6 (100%) of the trisomy 21 pregnancies and in 148 (19.4%), 57 (7.5%) and 106 (13.9%) of the normal pregnancies. For a detection rate of 100%, the false positive rates using the higher, smaller and average NT would be 5.1%, 45.9% and 4.2%, respectively.ConclusionIn monochorionic twins, effective screening for trisomy 21 is best provided by using the average NT measured in the two fetuses. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
Drugs for peptic ulcer
Authors: Clark Charles G. , Wyllie John H. 
Published: May 2005

AbstractConservative management of peptic ulcer relies on the use of drugs as an adjuvant to the time‐honored measures of avoiding stress, reducing gastric secretion, and regulating the diet. Alkalies neutralize acid and anticholinergic drugs partly inhibit secretion. Both are widely used but are often inadequate to control symptoms. Carbenoxolone appears to have a more specific effect in promoting healing of gastric ulcers and has now been used for 15 years. Its role in the treatment of gastric ulcer can be critically examined, particularly in relation to how this influences surgical management. Recently introduced compounds known as histamine H2‐receptor antagonists have a profound effect in inhibiting gastric secretion. Early experience in patients with duodenal ulcer indicates the efficacy of these compounds in promoting healing. These potent new drugs are likely to influence strongly the management of patients with duodenal ulcer, and this may affect the indications for surgery.
Review of elective surgical treatment of chronic duodenal ulcer
Authors: Feldman Stephen D. , Wise Leslie , Ballinger Walter F. 
Published: May 2005

AbstractThis article is a review of 20 clinical trials of various forms of elective surgical treatment of chronic duodenal ulcer conducted between 1964 and 1975, some of them prospective and others retrospective in nature. Comparisons have been made of the results following truncal vagotomy with drainage, truncal vagotomy with antrectomy, and partial gastrectomy. Additionally, selective vagotomy and truncal vagotomy have been compared in some studies and various forms of drainage, such as pyloroplasty and gastrojejunostomy, have been compared in others. In general, the results of all current forms of elective surgery for chronic duodenal ulcer have been very good, and the differences among the effects of the various procedures have been small. There have been no significant differences in the mortality rates associated with the several operations when they have been performed electively. The rate of ulcer recurrence and incidence of diarrhea have been somewhat higher after truncal vagotomy with drainage, whereas the frequency of dumping and amount of weight loss have been somewhat greater after all forms of gastric resection. Selective vagotomy appears to be associated with less frequent and severe diarrhea than does truncal vagotomy. There have been no apparent differences in the results of the various drainage procedures that have been combined with vagotomy. Highly selective vagotomy without drainage, the most recent operation for duodenal ulcer, has resulted in the lowest incidence of post‐operative side effects of any surgical procedure in current use. However, the frequency of ulcer recurrence after this therapeutic measure remains to be determined by long‐term studies.
Parietal cell (highly selective or proximal gastric) vagotomy for peptic ulcer disease
Authors: Amdrup Erik , Andersen Daniel , Jensen Hans ‐Eric 
Published: May 2005

AbstractParietal cell vagotomy has been in clinical use for 7 years in elective treatment of nonobstructive duodenal ulcer, and for even a shorter period for complicated cases and for gastric ulcer. The evolution of the surgical technique has not yet come to an end and the ability to perform the procedure is still improving. It can therefore be questioned, if this operation is yet ripe for a realistic clinical trial, and the great variation in recurrence rate reported in pilot series as well as in prospective randomized clinical trials points to the possibility that we will have to wait several years before the anticipated mean recurrence rate is known. At present it can be stated that even if gastric emptying is not quite undisturbed, the addition of a drainage procedure in nonobstructive cases is unnecessary. The same may be true in some patients with pyloric obstruction. Furthermore, the mortality rate is very low and the incidence of moderate‐to‐severe dumping and diarrhea is virtually nil.
Surgery for gastric ulcer
Authors: Duthie Herbert L. 
Published: May 2005

AbstractDespite the initial healing achieved by medical treatment with carbenoxolone, surgery is frequently needed in the management of gastric ulcer. We have studied 150 patients over the past 10 years in an attempt to define the place of conservative surgery compared with the standard partial gastrectomy of the Billroth I type. Functional results have not been significantly different and the individual surgeon's choice will depend on his philosophy with regard to the risk of cancer in the postoperative stomach, and his technical expertise with the newer kinds of vagotomy. To my mind it is perfectly justifiable to use highly selective vagotomy with excision of the ulcer to treat gastric ulcer alone, especially if the patient is one in whom postgastrectomy symptoms could be disabling. Further follow‐up is needed to decide whether it should replace partial gastrectomy as the standard procedure.
Progress in the treatment of acute gastroduodenal mucosal lesions (AGML)
Authors: Speranza Vincenzo , Basso Nicola 
Published: May 2005

AbstractThis article presents an analysis of acute gastroduodenal mucosal lesions (AGML) based on a review of current literature and the personal experience of the authors. The pathology of AGML involves two distinct types of lesions, namely, superficial erosions confined to the acid‐secreting gastric mucosa and presenting as erosive hemorrhagic gastritis, and acute ulcers that occur in the alkaline gastric mucosa and duodenum. The etiology of these two lesions is very likely different. Acute gastroduodenal ulcers, best known as stress ulcers, are probably “peptic” lesions, whereas erosive hemorrhagic gastritis appears to be due to pathologic back diffusion of hydrogen ions caused by a breakdown of the gastric mucosal barrier as a result of endogenous factors, such as gastric mucosal ischemia, and sometimes exogenous factors, such as alcohol, urea, and acetylsalicylic acid. Catecholamine hypersecretion resulting from severe stress, such as occurs in hypovolemia, sepsis, and hypercapnea, contributes to ischemia of the gastric mucosa by producing splanchnic vasoconstriction. The key to the diagnosis of AGML is early endoscopy in all cases of upper gastrointestinal bleeding. Therapy for AGML should begin with a trial of medical measures directed at restoring effective perfusion of tissues and removing hydrogen ions from the stomach by gastric washing. Medical therapy is effective in 80% of patients with erosive hemorrhagic gastritis, but surgical treatment is usually required in acute gastroduodenal ulcer. When surgery is necessary for either type of lesion, vagotomy with hemigastrectomy appears to be the most effective operation. The personal experience of the authors has involved 36 patients with AGML who were treated in three periods between 1968 and 1976. The mortality rate of patients with AGML has been reduced from 50% in the first 2 years to zero in the last 2 years by the use of emergency endoscopy for diagnosis, appropriate medical therapy, properly timed and executed surgery, and, most recently, selective angiography.