bluuebunny/crossref_metadata_2025_split huggingface dataset:
Probing the molecular weight distributions of non‐boiling petroleum fractions by Ag+ electrospray ionization mass spectrometry
Authors: Roussis Stilianos G. , Proulx Richard 
Published: July 2004

AbstractThis work explores the possibility of Ag+ electrospray ionization mass spectrometry (ESI‐MS) to determine the molecular weight distributions of non‐boiling petroleum fractions. Information about the molecular weight distributions is needed for fundamental studies on the nature of heavy crude oils and bitumens and for the development of novel recovery and processing methods. The method does not depend on thermal processes for the introduction of the fractions into the gas phase of the mass spectrometer, which is a considerable advantage over most other ionization methods. The Ag+ electrospray mass spectra of the fractions analyzed by using a toluene/methanol/cyclohexane (60:28:12%) solvent system display bimodal distributions in the ranges m/z ∼300 to ∼3000 and m/z 3000 to ∼20 000. The abundances of the high molecular weight peak distributions can be reduced by in‐source collisional activation experiments. Comparisons with the results obtained for model heteroatom‐containing compounds (molecular weight <600 Da) and high molecular weight polystyrene standards (up to one million Da) indicate that the majority of the structures in the saturate, naphthenoaromatic and polar aromatic fractions, and a significant portion of the asphaltenes, are small molecules. However, a considerable portion of the asphaltenes and some portion of the other fractions contain high molecular weight structures bound by covalent or strong non‐covalent bonds. The results obtained by the Ag+ ESI method in this study for the saturate, aromatic, and polar fractions in a bitumen are in qualitative agreement with published molecular weight average results obtained for Cold Lake bitumen fractions analyzed by conventional gel permeation chromatography and field desorption mass spectrometry. Further work is needed to study the nature of the bonds and the interactions of the molecules in the asphaltene fractions by Ag+ ESI‐MS. Copyright © 2004 John Wiley & Sons, Ltd.
Simultaneous quantitation of dexmedetomidine and glucuronide metabolites (G‐Dex‐1 and G‐Dex‐2) in human plasma utilizing liquid chromatography with tandem mass spectrometric detection
Authors: Ji Qin C. , Zhou Julie Y. , Gonzales R. John , Gage Eric M. , El‐Shourbagy Tawakol A. 
Published: July 2004

AbstractDexmedetomidine (Dex) (Precedex™) is a novel lipophilic imidazole derivative with a high affinity for alpha‐2 adrenergic receptors, which exhibits sedative, analgesic‐sparing, and sympatholytic properties. The pharmacological effects and therapeutic benefits of this drug have drawn continued interest from the medical community. Here we report a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method to simultaneously measure the concentrations of dexmedetomidine and its glucoronide metabolites, G‐Dex‐1 and G‐Dex‐2, in human plasma samples. A solid‐phase extraction method was developed to effectively extract Dex, G‐Dex‐1, and G‐Dex‐2 from plasma matrices. An isocratic chromatographic method was developed to achieve baseline separation of G‐Dex‐1 and G‐Dex‐2. The linear dynamic range evaluated was 19.08–1908.56 pg/mL for Dex, 65.17–6518.17 pg/mL for G‐Dex‐1, and 29.42–2943.28 pg/mL for G‐Dex‐2. The linear correlation coefficient (r) ranged from 0.9944–0.9979 for Dex, from 0.9966–0.9984 for G‐Dex‐1, and from 0.9939–0.9966 for G‐Dex‐2. The intra‐assay coefficient of variation (CV) was between 2.5–12.5% for Dex, between 5.2–11.0% for G‐Dex‐1, and between 3.5–12.1% for G‐Dex‐2. The inter‐assay precision of QC samples give % CV ranges from 6.5–9.3% for Dex, from 7.1–10.6% for G‐Dex‐1, and from 8.2–10.2% for G‐Dex‐2. The inter‐assay accuracies ranged from 102.0–109.3% for Dex, from 95.4–105.6% for G‐Dex‐1, and from 98.7–115.0% for G‐Dex‐2. Copyright © 2004 John Wiley & Sons, Ltd.
What Is Professional Development?
Authors: Schwartz Robert A. , Bryan William A. 
Published: July 2004

AbstractIt is quite clear that the diverse nature of the profession of student affairs, the vast array of institutions, and the incredible variety of student affairs professionals demand a wide range of opportunities and possibilities for professional development. This chapter sets the stage for the discussions that follow on personal and professional development. In particular, it examines the question, “What is staff development?”
Learning to write like a scientist: Coauthoring as an enculturation task
Authors: Florence Marilyn K. , Yore Larry D. 
Published: July 2004

AbstractThis multiple case study examined the coauthorship process in research laboratories of different university departments. The study focused on two cases comprising five writing teams, one in biochemistry and microbiology and four in earth and ocean sciences. The role of the research supervisor, the role of the student (graduate and postgraduate), the interaction of the supervisor and the student, the activities and processes inherent in the coauthorship process, and the student's beliefs, expertise, scientific writing, and entry into an academic discourse community were documented utilizing multiple sources of data and methods. Several activities and processes were found to be common across all coauthorship teams, including aspects of planning, drafting, and revising. Elements of scientific and writing expertise, facets of enculturation into scientific research and discourse communities, academic civility, and the dynamics of collaborative groups also were apparent. There was healthy tension and mutual respect in the research groups as they attempted to make sense of science, report their results clearly and persuasively, and share the responsibilities of expertise. The novice scientists came to appreciate that the writing, editing, and revising process influenced the quality of the science as well as the writing. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 637–668, 2004
Complete duplication of urinary bladder and urethra: prenatal sonographic features
Authors: Boopathy Vijayaraghavan S. , Nirmala A. B. 
Published: July 2004

AbstractPrenatal sonographic features of the rare anomaly of complete duplication of the urinary bladder and urethra are described in this case report. A coronal scan of the fetal pelvis at 29 weeks of gestation revealed two pyriform cystic structures. The umbilical arteries coursed around both of them. They emptied independently of each other. Postnatally the newborn had two vulvae, two anal openings, two bladders and two uteri. Copyright © 2004 ISUOG. Published by John Wiley & Sons, Ltd.
EDXRF analysis of red and white wines from Brazil
Authors: Anjos M. J. , Barroso R. C. , Lopes R. T. , de Jesus E. F. O. , Simabuco S. M. , Castro C. R. F. 
Published: July 2004

AbstractSeveral wines produced in different regions in southern Brazil and commercially available in Rio de Janeiro were analyzed for their contents of elements such as V, Fe, Ni, Cu, Zn, Mo and Pb. Multielement analysis was carried out with simple sample preparation and subsequent analysis by EDXRF spectrometry. The liquid residue was pre‐concentrated with the use of a chelating agent (ammonium pyrrolidinedithiocarbamate) and filtered through a Millipore filter (0.45 µm) by a vacuum pump. The experimental setup is based on a low‐power (2.25 W) miniaturized x‐ray tube and an Si(Li) detector. The levels of the various elements in the Brazilian wines are lower than those generally found in the literature, with the exception of Mo. The present study indicates the capability of multielement analysis for determining the contents of various elements present in wines by using a simple, sensitive and precise method. Copyright © 2004 John Wiley & Sons, Ltd.
ASYMPTOTIC BEHAVIOUR AND BLOW-UP FOR A NONLINEAR DIFFUSION PROBLEM WITH A NON-LOCAL SOURCE TERM
Authors: Kavallaris N. I. 
Published: July 2004

AbstractIn this work, the behaviour of solutions for the Dirichlet problem of the non-local equation$$ u_t=\varDelta(\kappa(u))+\frac{\lambda f(u)}{(\int_{\varOmega}f(u)\,\mathrm{d}x)^p},\quad \varOmega\subset\mathbb{R}^N,\quad N=1,2, $$is studied, mainly for the case where $f(s)=\mathrm{e}^{\kappa(s)}$. More precisely, the interplay of exponent $p$ of the non-local term and spatial dimension $N$ is investigated with regard to the existence and non-existence of solutions of the associated steady-state problem as well as the global existence and finite-time blow-up of the time-dependent solutions $u(x,t)$. The asymptotic stability of the steady-state solutions is also studied.AMS 2000 Mathematics subject classification: Primary 35K60. Secondary 35B40
Cost-effectiveness of digital photographic screening for retinopathy of prematurity in the United Kingdom
Authors: Castillo-Riquelme Marianela C. , Lord Joanne , Moseley Merrick J. , Fielder Alistair R. , Haines Linda 
Published: July 2004

Objectives:To compare the cost-effectiveness of alternative methods of screening for retinopathy of prematurity (ROP) in the United Kingdom, including the existing method of indirect ophthalmoscopy by ophthalmologists and digital photographic screening by nurses.Methods:A decision tree model was used to compare five screening modalities for the UK population of preterm babies, using a health service perspective. Data were taken from published sources, observation at a neonatal intensive care unit (NICU), and expert judgment.Results:We estimated that use of standard digital cameras by nurses in NICUs would cost more than current methods (£371 compared with £321 per baby screened). However, a specialist nurse visiting units with a portable camera would be cheaper (£172 per baby). These estimates rely on nurses capturing and interpreting the images, with suitable training and supervision. Alternatively, nurses could capture the images then transmit them to a central unit for interpretation by ophthalmologists, although we estimate that this would be rather more expensive (£390 and £201, respectively, for NICU and visiting nurses). Sensitivity analysis was used to examine the robustness of estimates.Conclusions:It is likely that there is an opportunity to improve the efficiency of the ROP screening program. We estimate that screening by specialist nurses trained in image capture and interpretation using portable digital cameras is a cost-effective alternative to the current program of direct visualization by ophthalmologists. This option would require the development of a suitable portable machine. Direct comparative research is strongly needed to establish the accuracy of the various screening options.
Neuroprotective efficacy and therapeutic time window of peroxynitrite decomposition catalysts in focal cerebral ischemia in rats#
Authors: Thiyagarajan Meenakshisundaram , Kaul Chaman Lal , Sharma Shyam Sundar 
Published: July 2004

Free radicals have been implicated in cerebral ischemia reperfusion (IR) injury. Massive production of nitric oxide and superoxide results in continuous formation of peroxynitrite even several hours after IR insult. This can produce DNA strand nicks, hydroxylation and/or nitration of cytosolic components of neuron, leading to neuronal death. Peroxynitrite decomposition catalysts 5,10,15,20‐tetrakis(N‐methyl‐4′‐pyridyl)porphyrinato iron (III) (FeTMPyP) and 5,10,15,20‐tetrakis(4‐sulfonatophenyl)porphyrinato iron (III) (FeTPPS) have been demonstrated to protect neurons in in vitro cultures; however, their neuroprotective efficacy in cerebral IR injury has not been explored.
In the present study, we investigated the efficacy and the therapeutic time window of FeTMPyP and FeTPPS in focal cerebral ischemia (FCI).
FCI was induced according to the middle cerebral artery occlusion (MCAO) method. After 2 h of MCAO and 70 h of reperfusion, the extent of neurological deficits, infarct and edema volume were measured in Sprague–Dawley rats.
FeTMPyP and FeTPPS were administered at different time points 2, 6, 9 and 12 h post MCAO. FeTMPyP and FeTPPS (3 mg kg−1, i.v.) treatment at 2 and 6 h post MCAO produced significant reduction in infarct volume, edema volume and neurological deficits. However, treatment at latter time points did not produce significant neuroprotection.
Significant reduction of peroxynitrite in blood and nitrotyrosine in brain sections was observed on FeTMPyP and FeTPPS treatment.
As delayed treatment of FeTMPyP and FeTPPS produced neuroprotection, we tested whether treatment had any influence over the apoptotic neuronal death. DNA fragmentation and in situ nick end‐labeling assays showed that FeTMPyP and FeTPPS treatment reduced IR injury‐induced DNA fragmentation.
In conclusion, peroxynitrite decomposition catalysts (FeTMPyP and FeTPPS) produced prominent neuroprotection even if administered 6 h post MCAO and the neuroprotective effect is at least in part due to the reduction of peroxynitrite and apoptosis.

British Journal of Pharmacology (2004) 142, 899–911. doi:10.1038/sj.bjp.0705811
Synergistic interaction between enalapril, L‐arginine and tetrahydrobiopterin in smooth muscle cell apoptosis and aortic remodeling induction in SHR
Authors: Sarkissian Shant Der , Marchand Eve‐Lyne , Duguay David , DeBlois Denis 
Published: July 2004

Smooth muscle cell (SMC) apoptosis occurs at the onset of enalapril‐induced regression of aortic hypertrophy in SHR. A potential mechanism is the correction of endothelial dysfunction (ED) leading to reduced production of reactive oxygen species and enhanced bioavailability of nitric oxide (NO), a potent apoptosis inducer. Stimulants of NO include the precursor L‐arginine and the NO synthase cofactor tetrahydrobiopterin (BH4), which correct ED in several models.
The objective was to examine the relationships between ED and the cell growth/death balance during vascular remodeling induced by enalapril in SHR.
SHR, 10‐week‐old, received enalapril (ENA: 30 mg.kg−1.day−1 p.o.) for 1 or 2 weeks, or a co‐treatment of L‐arginine (2.0 g.kg−1.day−1 p.o.) and BH4 (5.4 mg.kg−1.day−1 i.p. twice daily) administered alone (group: LB) or in combination with enalapril (ENA+LB) for 1 week. Controls received vehicle.
After 1 week, ED was completely corrected with LB but not affected significantly by ENA, whereas both treatments failed to induce SMC apoptosis or aortic remodeling. The correction of ED and the induction of SMC apoptosis (3.3‐fold increase in TUNEL labeling) required 2 weeks of ENA treatment. The combination of LB with ENA for 1 week, however, was additive for the reduction of SMC proliferation, and synergistic for the induction of apoptosis and regression of vascular hypertrophy. These interactions were independent of blood pressure regulation.
Our results suggest that the correction of ED is not sufficient to induce SMC apoptosis and vascular remodeling, although it facilitates these responses during enalapril treatment.

British Journal of Pharmacology (2004) 142, 912–918. doi:10.1038/sj.bjp.0705830
AT2 receptor‐mediated vasodilatation is unmasked by AT1 receptor blockade in conscious SHR
Authors: Li Xiao C , Widdop Robert E 
Published: July 2004

In the present study, we investigated the role of the angiotensin II type 2 receptor (AT2) receptor in the regulation of regional haemodynamics in spontaneously hypertensive rats (SHR). We tested the hypothesis that AT2 receptor activation directly causes vasodilatation.
Mean arterial pressure (MAP), renal, mesenteric and hindquarters flows and conductances were measured in various groups of conscious rats that received the following drug combinations on separate days: the AT1 receptor antagonist, candesartan (5 or 10 μg kg−1 i.v.) alone, the AT2 receptor agonist, CGP42112 (1 μg kg−1 min−1) alone and candesartan plus CGP42112.
Low‐dose candesartan (5 μg kg−1) caused renal vasodilatation, while CGP 42112 alone caused minimal haemodynamic effects. In the presence of candesartan, CGP42112 caused a marked depressor effect together with generalised vasodilatation that was abolished by the coinfusion of the AT2 receptor antagonist, PD123319 (50 μg kg−1 min−1), with the candesartan and CGP42112 combination. PD123319, given alone, increased MAP and reduced renal and mesenteric conductances.
We also confirmed that the enhanced vasodilatation evoked by candesartan plus CGP42112 was not due to additional AT1 receptor blockade, since angiotensin II‐mediated vasoconstriction was inhibited by a similar magnitude in the combination treatment compared with candesartan alone. Analogous experiments in Wistar–Kyoto rats did not demonstrate significantly enhanced effects due to candesartan plus CGP42112.
Collectively, these data suggest that, in SHR, AT2 receptors tonically modulate vascular tone and that direct AT2 receptor‐mediated vasodilatation was unmasked by AT1 receptor blockade.

British Journal of Pharmacology (2004) 142, 821–830. doi:10.1038/sj.bjp.0705838
Subtype specific internalization of P2Y1 and P2Y2 receptors induced by novel adenosine 5′‐O‐(1‐boranotriphosphate) derivatives
Authors: Tulapurkar M E , Laubinger W , Nahum V , Fischer B , Reiser G 
Published: July 2004

P2Y‐nucleotide receptors represent important targets for drug development. The lack of stable and receptor specific agonists, however, has prevented successful therapeutic applications. A novel series of P‐boronated ATP derivatives (ATP‐α‐B) were synthesized by substitution of a nonbridging O at P with a BH3 group. This introduces a chiral center, thus resulting in diastereoisomers. In addition, at C2 of the adenine ring a further substitution was made (Cl‐ or methylthio‐). The pairs of diastereoisomers were denoted here as A and B isomers.
Here, we tested the receptor subtype specificity of these analogs on HEK 293 cells stably expressing rat P2Y1 and rat P2Y2 receptors, respectively, both attached to the fluorescent marker protein GFP (rP2Y1‐GFP, rP2Y2‐GFP). We investigated agonist‐induced receptor endocytosis, [Ca2+]i rise and arachidonic acid (AA) release.
Agonist‐induced endocytosis of rP2Y1‐GFP was more pronounced for the A isomers than the corresponding B counterparts for all ATP‐α‐B analogs. Both 2‐MeS‐substituted diastereoisomers induced a greater degree of agonist‐induced receptor endocytosis as compared to the 2‐Cl‐substituted derivatives. Endocytosis results are in accordance with the potency to induce Ca2+ release by these compounds in HEK 293 cells stably transfected with rP2Y1.
In case of rP2Y2‐GFP, the borano‐nucleotides were very weak agonists in comparison to UTP and ATP in terms of Ca2+ release, AA release and in inducing receptor endocytosis. The different ATP‐α‐B derivatives and also the diastereoisomers were equally ineffective.
Thus, the new agonists may be considered as potent and highly specific agonist drug candidates for P2Y1 receptors. The difference in activity of the ATP analogs at P2Y receptors could be used as a tool to investigate structural differences between P2Y receptor subtypes.

British Journal of Pharmacology (2004) 142, 869–878. doi:10.1038/sj.bjp.0705859
Polymorphisms in TDG and MGMT Genes – Epidemiological and Functional Study in Lung Cancer Patients from Poland
Authors: Krześniak M. , Butkiewicz D. , Samojedny A. , Chorży M. , Rusin M. 
Published: July 2004

SummaryFunctional genetic polymorphisms of DNA repair genes are good candidates for cancer susceptibility markers. We studied two genes coding for proteins removing small DNA adducts by direct repair (MGMT), or mispaired DNA bases by base excision repair (TDG). The non‐silent polymorphisms of MGMT (84:Phe, 143:Val, 178:Arg) and TDG (199:Ser, 367:Met), and the functional MGMT enhancer polymorphism, did not show any statistically significant association with lung cancer risk in our case‐control analysis, but due to the relatively small number of individuals, strong conclusions on cancer risk association or lack thereof cannot be made. Sequencing of the TDG cDNA has not revealed any novel polymorphism, but did find an alternatively spliced mRNA missing exon 2. Our search for polymorphisms within the promoter‐enhancer region of MGMT revealed three novel sequence variants. The functional significance of the previously published MGMT enhancer polymorphism (1099C‐>T) was assessed. The less frequent sequence variant of the enhancer was associated with a modest (16–64%), but statistically significant, increase of MGMT promoter‐enhancer activity in the studied cell lines. This work points to the importance of studying the expression‐regulating elements of genes, as they may contain functional polymorphisms with the potential for modulating risk of various diseases, including cancer.
MtDNA Profile of West Africa Guineans: Towards a Better Understanding of the Senegambia Region
Authors: Rosa Alexandra , Brehm António , Kivisild Toomas , Metspalu Ene , Villems Richard 
Published: July 2004

SummaryThe matrilineal genetic composition of 372 samples from the Republic of Guiné‐Bissau (West African coast) was studied using RFLPs and partial sequencing of the mtDNA control and coding region. The majority of the mtDNA lineages of Guineans (94%) belong to West African specific sub‐clusters of L0‐L3 haplogroups. A new L3 sub‐cluster (L3h) that is found in both eastern and western Africa is present at moderately low frequencies in Guinean populations. A non‐random distribution of haplogroups U5 in the Fula group, the U6 among the “Brame” linguistic family and M1 in the Balanta‐Djola group, suggests a correlation between the genetic and linguistic affiliation of Guinean populations. The presence of M1 in Balanta populations supports the earlier suggestion of their Sudanese origin. Haplogroups U5 and U6, on the other hand, were found to be restricted to populations that are thought to represent the descendants of a southern expansion of Berbers. Particular haplotypes, found almost exclusively in East‐African populations, were found in some ethnic groups with an oral tradition claiming Sudanese origin.
Computational prediction of RNA editing sites
Authors: Bundschuh R. 
Published: July 2004

Abstract
Motivation: Some organisms edit their messenger RNA resulting in differences between the genomic sequence for a gene and the corresponding messenger RNA sequence. This difference complicates experimental and computational attempts to find and study genes in organisms with RNA editing even if the full genomic sequence is known. Nevertheless, knowledge of these editing sites is crucial for understanding the editing machinery of these organisms.
Results: We present a computational technique that predicts the position of editing sites in the genomic sequence. It uses a statistical approach drawing on the protein sequences of related genes and general features of editing sites of the organism. We apply the method to the mitochondrion of the slime mold Physarum polycephalum. It correctly predicts over 90% of the amino acids and over 70% of the editing sites.
Availability: The source code is available upon request from the author.