bluuebunny/crossref_metadata_2025 huggingface dataset:
The Amino Terminus of the Saccharomyces cerevisiae DNA Helicase Rrm3p Modulates Protein Function Altering Replication and Checkpoint Activity
Authors: Bessler Jessica B , Zakian Virginia A
Published: December 2004

The Pif1 family of DNA helicases is conserved from yeast to humans. Although the helicase domains of family members are well conserved, the amino termini of these proteins are not. The Saccharomyces cerevisiae genome encodes two Pif1 family members, Rrm3p and Pif1p, that have very different functions. To determine if the amino terminus of Rrm3p contributes to its role in promoting fork progression at >1000 discrete chromosomal sites, we constructed a deletion series that lacked portions of the 249-amino-acid amino terminus. The phenotypes of cells expressing alleles that lacked all or most of the amino terminus were indistinguishable from those of rrm3Δ cells. Rrm3p deletion derivatives that lacked smaller portions of the amino terminus were also defective, but the extent of replication pausing at tRNA genes, telomeres, and ribosomal DNA (rDNA) was not as great as in rrm3Δ cells. Deleting only 62 amino acids from the middle of the amino terminus affected only rDNA replication, suggesting that the amino terminus can confer locus-specific effects. Cells expressing a fusion protein consisting of the Rrm3p amino terminus and the Pif1p helicase domain displayed defects similar to rrm3Δ cells. These data demonstrate that the amino terminus of Rrm3p is essential for Rrm3p function. However, the helicase domain of Rrm3p also contributes to its functional specificity.
Host Factors That Affect Ty3 Retrotransposition in Saccharomyces cerevisiae
Authors: Aye Michael , Irwin Becky , Beliakova-Bethell Nadejda , Chen Eric , Garrus Jennifer , Sandmeyer Suzanne
Published: December 2004

The retrovirus-like element Ty3 of Saccharomyces cerevisiae integrates at the transcription initiation region of RNA polymerase III. To identify host genes that affect transposition, a collection of insertion mutants was screened using a genetic assay in which insertion of Ty3 activates expression of a tRNA suppressor. Fifty-three loci were identified in this screen. Corresponding knockout mutants were tested for the ability to mobilize a galactose-inducible Ty3, marked with the HIS3 gene. Of 42 mutants tested, 22 had phenotypes similar to those displayed in the original assay. The proteins encoded by the defective genes are involved in chromatin dynamics, transcription, RNA processing, protein modification, cell cycle regulation, nuclear import, and unknown functions. These mutants were induced for Ty3 expression and assayed for Gag3p protein, integrase, cDNA, and Ty3 integration upstream of chromosomal tDNAVal(AAC) genes. Most mutants displayed differences from the wild type in one or more intermediates, although these were typically not as severe as the genetic defect. Because a relatively large number of genes affecting retrotransposition can be identified in yeast and because the majority of these genes have mammalian homologs, this approach provides an avenue for the identification of potential antiviral targets.
Uncovering Novel Cell Cycle Players Through the Inactivation of Securin in Budding Yeast
Authors: Sarin Sumeet , Ross Karen E , Boucher Lorrie , Green Yvette , Tyers Mike , Cohen-Fix Orna
Published: December 2004

Budding yeast securin/Pds1p, an inhibitor of the anaphase activator separase/Esp1p, is involved in several checkpoint pathways and in promoting Esp1p's nuclear localization. Using a modified synthetic genetic array (SGA) screen for genes that become essential in the absence of Pds1p, we uncovered roles for uncharacterized genes in cell cycle processes, including Esp1p activation.
Phylogenetic Analysis of 5′-Noncoding Regions From the ABA-Responsive rab16/17 Gene Family of Sorghum, Maize and Rice Provides Insight Into the Composition, Organization and Function of cis-Regulatory ModulesSequence data from this article have been deposited with the EMBL/GenBank Data Libraries under accession no. AY177889.
Authors: Buchanan Christina D , Klein Patricia E , Mullet John E
Published: December 2004

Phylogenetic analysis of sequences from gene families and homologous genes from species of varying divergence can be used to identify conserved noncoding regulatory elements. In this study, phylogenetic analysis of 5′-noncoding sequences was optimized using rab17, a well-characterized ABA-responsive gene from maize, and five additional rab16/17 homologs from sorghum and rice. Conserved 5′-noncoding sequences among the maize, sorghum, and rice rab16/17 homologs were identified with the aid of the software program FootPrinter and by screening for known transcription-factor-binding sites. Searches for 7 of 8 (7/8)bp sequence matches within aligned 5′-noncoding segments of the rab genes identified many of the cis-elements previously characterized by biochemical analysis in maize rab17 plus several additional putative regulatory elements. Differences in the composition of conserved noncoding sequences among rab16/17 genes were related to variation in rab gene mRNA levels in different tissues and to response to ABA treatment using qRT-PCR. Absence of a GRA-like element in the promoter of sorghum dhn2 relative to maize rab17 was correlated with an ∼85-fold reduction of dhn2 RNA in sorghum shoots. Overall, we conclude that phylogenetic analysis of gene families among rice, sorghum, and maize will help identify regulatory sequences in the noncoding regions of genes and contribute to our understanding of grass gene regulatory networks.
Insertion-Sequence-Mediated Mutations Isolated During Adaptation to Growth and Starvation in Lactococcus lactis
Authors: de Visser J Arjan G M , Akkermans Antoon D L , Hoekstra Rolf F , de Vos Willem M
Published: December 2004

We studied the activity of three multicopy insertion sequence (IS) elements in 12 populations of Lactococcus lactis IL1403 that evolved in the laboratory for 1000 generations under various environmental conditions (growth or starvation and shaken or stationary). Using RFLP analysis of single-clone representatives of each population, nine IS-mediated mutations were detected across all environmental conditions and all involving IS981. When it was assumed that these mutations were neutral, their frequency was higher under shaken than under stationary conditions, possibly due to oxygen stress. We characterized seven of the nine mutations at the molecular level and studied their population dynamics where possible. Two were simple insertions into new positions and the other five were recombinational deletions (of <1–>10 kb) among existing and new copies of IS981; in all but one case these mutations disrupted gene functions. The best candidate beneficial mutations were two deletions of which similar versions were detected in two populations each. One of these two parallel deletions, affecting a gene involved in bacteriophage resistance, showed intermediate rearrangements and may also have resulted from increased local transposition rates.
Subtelomeric 6p deletion: Clinical, FISH, and array CGH characterization of two cases
Authors: Le Caignec Cédric , De Mas Philippe , Vincent Marie‐Claire , Bocéno Michelle , Bourrouillou Georges , Rival Jean‐Marie , David Albert
Published: December 2004

Thirty patients have been described with cytogenetically visible deletion of the short arm of chromosome 6. However, subtelomeric 6p deletion detected by subtelomeric specific probes has been reported only twice. We report two new patients with terminal 6p deletion detected by subtelomeric screening using fluorescence in situ hybridization (FISH). The two patients exhibited mental retardation, ocular abnormalities, hearing loss, and a characteristic facial appearance. Detailed FISH analyses with probes covering the distal 6p25 region estimated the size of the terminal deletions to ≈5.5 Mb and ≈4.8 Mb. Array‐based comparative genomic hybridization (array CGH) was used to confirm the cryptic deletions. Most patients with subtelomeric defects lack a characteristic phenotype. However, some of the subtelomeric deletions result in a specific phenotype, which can direct the clinician towards the diagnosis. Submicroscopic 6p deletion appears to be a recognizable clinical phenotype, and this region should be thoroughly investigated with FISH probes, including at least a subtelomeric 6p probe and a probe covering FOXC1, for patients presenting with a characteristic facial appearance, ocular abnormalities, predominantly anterior‐chamber eye defects, hearing loss, and mental retardation. © 2004 Wiley‐Liss, Inc.
A clinical report of a patient with two abnormal cell lines: 46,XX,del(21)(q22.1) and 47,XX,+3
Authors: Quigley Denise I. , Sailus Jeffery , Kaiser‐Rogers Kathleen , Rao Kathleen W. , Calikoglu Muge , Gold Stuart , McCandless Shawn E.
Published: December 2004

Mosaicism for two chromosomally abnormal cell lines in the absence of a normal cell line is exceedingly rare. We report a patient with developmental and growth delay, mild dysmorphic features, a history of hypertension and hepatoblastoma who was found to be mosaic for two chromosomally abnormal cell lines. The cell lines, one containing a terminally deleted chromosome 21, the other trisomy 3, were found in her blood. Fibroblasts and hepatoblastoma tumor cells revealed only the presence of the deleted 21 cell line. Microsatellite marker analysis suggests a mosaic rather than chimeric etiology for the cell lines. This case is exceptional in that the presence of either of these two cell lines alone is uncommon; finding both of these cell lines in an individual appears to be unique. © 2004 Wiley‐Liss, Inc.
A locus for Bowen–Conradi syndrome maps to chromosome region 12p13.3
Authors: Lamont Ryan E. , Loredo‐Osti JC. , Roslin Nicole M. , Mauthe Jill , Coghlan Gail , Nylen Edward , Frappier Danielle , Innes A. Micheil , Lemire Edward G. , Lowry R. Brian , Greenberg Cheryl R. , Triggs‐Raine Barbara L. , Morgan Kenneth , Wrogemann Klaus , Fujiwara T. Mary , Zelinski Teresa
Published: December 2004

Bowen–Conradi syndrome (BCS) is a lethal autosomal recessive disorder with an estimated incidence of 1 in 355 live births in the Hutterite population. A few cases have been reported in other populations. Here, we report the results of a genome‐wide scan and fine mapping of the BCS locus in Hutterite families. By linkage and haplotype analysis the BCS locus was mapped to a 3.5 cM segment (1.9 Mbp) in chromosome region 12p13.3 bounded byF8VWFandD12S397. When genealogical relationships among the families were taken into account in the linkage analysis, the evidence for linkage was stronger and the number of potentially linked regions was reduced to one. Under the assumption that all the Hutterite patients were identical by descent for a disease‐causing mutation, haplotype analysis was used to infer likely historical recombinants and thereby narrow the candidate region to a chromosomal segment shared in common by all the affected children. This study also demonstrates that BCS and cerebro‐oculo‐facial‐skeletal syndrome (COFS) are genetically distinct. © 2004 Wiley‐Liss, Inc.
Endothelin‐mediated remodeling in aortas of diabetic rats
Authors: Fukuda Gen , Khan Zia A. , Barbin Yousef P. , Farhangkhoee Hana , Tilton Ronald G. , Chakrabarti Subrata
Published: December 2004

Background

Smooth muscle cells proliferation and extracellular matrix (ECM) protein deposition are key features of diabetic macroangiopathy. In the present study, we have studied the role of endothelinA(ETA) receptor, the predominant receptor on smooth muscle cells, in diabetes‐induced vascular hypertrophy and remodeling.

Methods

Streptozotocin‐induced diabetic rats were administrated a selective ETAreceptor antagonist, TBC3214, for 26 weeks. Following treatment, aortas were harvested and subjected to gene expression and morphometric analyses. We quantified fibronectin (FN) and plasminogen activator inhibitor‐1 (PAI‐1) expression as indicators of increased ECM protein synthesis. ET‐1, ET‐3, transforming growth factor‐β1 (TGF‐β1) and angiotensinogen mRNA levels were measured to elucidate genes involved in FN expression. We have investigated an embryonic splice variant of FN, oncofetal FN, and nonmuscle myosin heavy chain (SMemb) as vascular remodeling indicators.

Results

Our results show that diabetes leads to upregulation of FN, PAI‐1, ET‐1, ET‐3, TGF‐β1 and angiotensinogen mRNA levels in association with increased medial thickness. Immunohistochemical analyses revealed concurrent protein level changes. Diabetes also upregulated oncofetal FN and SMemb mRNA levels. Treatment with TBC3214 attenuated the mRNA levels of several genes and prevented increased medial thickness.

Conclusions

These results indicate that diabetes‐induced vascular hypertrophy and remodeling is associated with reexpression of embryonic forms of FN and myosin heavy chain. Such changes are ET‐dependent and may be mediated via TGF‐β1 and angiotensin. Copyright © 2004 John Wiley & Sons, Ltd.
Differential expression of tyrosinated tubulin in Spisula solidissima polar bodies
Authors: Alliegro Mark C. , Alliegro Mary Anne
Published: December 2004

The C‐terminus of α‐tubulin can be reversibly modified by a specific tyrosine ligase to yield an isoform known as Tyr‐tubulin. Tyr‐tubulin is typically found in more dynamic microtubule arrays such as the mitotic spindle, as opposed to stable structures like centrioles and flagella. In developing systems, it is expressed in relatively undifferentiated, proliferative cell types but is replaced by detyrosinated (Glu‐) tubulin during differentiation. We found Tyr‐tubulin highly enriched in a single polar body of Spisula solidissima embryos. Quantitation of DNA content by Hoechst staining indicates that polar body 1 (with twice the DNA content of polar body 2) is the Tyr‐tubulin–positive cell. Other than the apoptosis marker caspase, this is, to our knowledge, the first distinguishing marker antigen for polar bodies, particularly for one polar body vs. another. This localization of Tyr‐tubulin is unlikely to be a byproduct of the meiotic process itself, because it arises after ejection of both polar bodies is complete. Although polar bodies are typically thought of as a terminally differentiated vestige of meiosis, the localization of this more dynamic tubulin isoform suggests an active role in early development. Developmental Dynamics 232:216–220, 2005. © 2004 Wiley‐Liss, Inc.
Phenotypic analyses of mouse embryos with ubiquitous expression of Oct4: Effects on mid–hindbrain patterning and gene expression
Authors: Ramos‐Mejía Verónica , Escalante‐Alcalde Diana , Kunath Tilo , Ramírez Laura , Gertsenstein Marina , Nagy Andras , Lomelí Hilda
Published: December 2004

Oct4 is a transcription factor that has been associated with pluripotency and fate determination in the initial cell lineages of mammals. On the other hand, Pou2, the ortholog of Oct4 in zebrafish, serves additional later functions during brain development acting as a differentiation switch. In mice, Oct4 is expressed throughout the neural plate of embryos until embryonic day (E) 8.0. In this study, we produced transgenic mouse embryos that ubiquitously express Oct4 and analyzed the consequences during development. We show that, at E8.0, a higher dosage of Oct4 in the neuroectoderm is sufficient to transiently alter mid–hindbrain patterning and produced a strong up‐regulation of Pax2, indicating that Oct4 can regulate this gene in vivo. After E9.5, ectopic Oct4 in this region produced cell death and affected the development of the forebrain, suggesting that, at these later stages, Oct4 down‐regulation is necessary for normal development to proceed. The phenotype of the transgenic embryos was also accompanied with an increase of Fgf8 expression in several of its endogenous domains, suggesting the possibility that Oct4 can participate in the regulation of expression of this ligand. Our observations support the hypothesis that Oct4, like zebrafish Pou2, has a conserved function during early brain patterning in mouse. Developmental Dynamics 232:180–190, 2005. © 2004 Wiley‐Liss, Inc.
Mph2 expression in germinal zones of the mouse brain
Authors: Kim Mary H. , Gunnersen Jenny M. , Tan Seong‐Seng
Published: December 2004

The telencephalon develops from a seemingly homogeneous population of precursor cells that generates neurons with divergent properties and cell fates. An important question concerns the genetic control of cell states belonging to different generations. Mph2 was identified by serial analysis of gene expression as a differentially expressed gene during cortical development. Belonging to the Polycomb group, Mph2 may be involved in transcriptional repression of cell states from one generation to the next. Here, we use in situ hybridization to determine the spatial localization of Mph2 expression in the developing nervous system. Mph2 expression evident in proliferating precursor cell populations in the developing mouse brain such as the ventricular zones of the cortex and ganglionic eminences as well as in mature structures such as the granule cell layer of the adult dentate gyrus and cerebellum indicates a role for Mph2 in both the developing and adult brain. Developmental Dynamics 232:209–215, 2005. © 2004 Wiley‐Liss, Inc.
Transduction of naive CD4 T cells with kinase‐deficient Lck‐HIV‐Tat fusion protein dampens T cell activation and provokes a switch to regulatory function
Authors: Veldhoen Marc , Magee Anthony I. , Penha‐Goncalves Mario N. , Stockinger Brigitta
Published: December 2004

We show here that T cell differentiation can be altered by exposing naive mouse CD4 T cells to altered T cell receptor signaling, achieved by transducing them with a fusion protein consisting of a modified Lck protein lacking the kinase domain and the HIV‐Tat protein transduction domain. The Lck‐HIV‐Tat fusion protein is internalized into naive mouse T cells within 30 min after application to the medium. Activation of transduced cells in vitro resulted in strongly reduced intracellular calcium mobilization, alterations in cytokine profile, and sustained up‐regulation of CD25. The cells had suppressive activity in vitro, but no Foxp3 expression. Our data indicate that signals encountered by a naive T cell during its initial activation can profoundly influence its subsequent functional behavior and elicit T cells, which can have regulatory activity.
Value at risk from econometric models and implied from currency options
Authors: Chong James
Published: December 2004

This paper compares daily exchange rate value at risk estimates derived from econometric models with those implied by the prices of traded options. Univariate and multivariate GARCH models are employed in parallel with the simple historical and exponentially weighted moving average methods. Overall, we find that during periods of stability, the implied model tends to overestimate value at risk, hence over‐allocating capital. However, during turbulent periods, it is less responsive than the GARCH‐type models, resulting in an under‐allocation of capital and a greater number of failures. Hence our main conclusion, which has important implications for risk management, is that market expectations of future volatility and correlation, as determined from the prices of traded options, may not be optimal tools for determining value at risk. Therefore, alternative models for estimating volatility should be sought. Copyright © 2004 John Wiley & Sons, Ltd.
Student activism at Ithaca College: Reflections on management and leadership
Authors: Williams Peggy R. , McGreevey Michael R.
Published: December 2004

When a seemingly routine management decision sparks heated controversy on a college campus, the president must decide how to respond to students occupying a building and issuing an ultimatum to the administration.
Profiling histidine‐containing dipeptides in rat tissues by liquid chromatography/electrospray ionization tandem mass spectrometry
Authors: Aldini Giancarlo , Orioli Marica , Carini Marina , Maffei Facino Roberto
Published: December 2004

The histidine‐containing dipeptides carnosine (CAR) and structurally related anserine (ANS) and homocarnosine (HCAR), widely distributed in vertebrate organisms, have recently been proposed as endogenous quenchers for highly cytotoxic α,β‐unsaturated aldehydes generated by peroxidation. A sensitive, selective, specific and rapid liquid chromatographic/electrospray ionization tandem mass spectrometric assay was developed and validated for the simultaneous determination of these peptides in biological matrices in order to establish their plasma/tissue distribution. Samples (plasma or tissue homogenates from male rats) were prepared by protein precipitation with HClO4 (1 : 1, v/v) containing H‐Tyr‐His‐OH as internal standard. The supernatant was separated on a Phenomenex Sinergy polar‐RP column with a mobile phase of water–acetonitrile–heptafluorobutyric acid (9 : 1 : 0.01, v/v/v) at a flow‐rate of 0.2 ml min−1, with a run time of 10 min. Detection was effected on an ion trap mass spectrometer equipped with an electrospray ionization interface operating in positive ionization mode. The acquisitions were in the multiple reaction monitoring mode using the following precursor → product ion combinations: H‐Tyr‐His‐OH (internal standard) m/z 319 → 301; CAR m/z 227 → 210 + 209; ANS m/z 241 → 224 + 197 + 170; HCAR m/z 241 → 156. The method was validated over the concentration range 15–1000 nmol g−1 and the limit of quantification (LOQ) and limit of detection (LOD) were 12.5 and 4.2 pmol injected, respectively. The intra‐ and inter‐day precisions were <10% (≤17.47% at the LOQ) and the intra‐ and inter‐assay accuracies were within ±10% for all concentrations. The mapping profile in rat tissue gave the following results: the highest concentrations of CAR and ANS were found in skeletal muscles (soleus, gastrocnemius, tibialis), followed by the heart, cerebellum and brain (ANS below the LOQ). HCAR was found only in the brain and cerebellum. No histidine‐containing dipeptides were detectable in plasma, liver, kidney and lung. Copyright © 2004 John Wiley & Sons, Ltd.
Identification of proteins by combination of size‐exclusion chromatography with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and comparison of some desalting procedures for both intact proteins and their tryptic digests
Authors: Šalplachta Jiří , Řehulka Pavel , Chmelík Josef
Published: December 2004

Separation of a protein mixture by size‐exclusion chromatography (SEC) was combined with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). Identification of proteins in the collected fractions was performed both as intact proteins by MALDI‐TOFMS and using peptide mass fingerprinting (PMF) after their digestion with trypsin. The presence of salts mostly disturbs the MALDI‐TOFMS signal and, therefore, proper purification or desalting procedures must be employed. Four desalting procedures (desalting column packed with Sephadex G‐100, on‐target washing, centrifugal filter devices and ZipTip C18) for purification of fractions of proteins separated by SEC and their tryptic digests prior to determination of their exact molecular masses by MALDI‐TOFMS were compared. In the case of intact proteins, the experiments showed that the best desalting procedures are the use of ZipTip C18 pipette tips and Ultrafree CL centrifugal filter devices. The peptide digests can be purified by using ZipTip C18 pipette tips or on‐target washing when both of these procedures provide similar results. On‐target washing can be used as a simple procedure to improve the mass spectra of salt‐containing samples. Analyses of the droplets collected after the on‐target washing show losses of sample and matrix caused by dissolution of these compounds during this procedure. Further, it was found that protein identification based on PMF is more sensitive than analyses of intact proteins and that multiple on‐target washing is very advantageous for analyses of peptide mixtures with a high content of salts. Copyright © 2004 John Wiley & Sons, Ltd.
Characterization of the disulfides of bio‐thiols by electrospray ionization and triple‐quadrupole tandem mass spectrometry
Authors: Rubino Federico Maria , Verduci Cinzia , Giampiccolo Rosario , Pulvirenti Salvatore , Brambilla Gabri , Colombi Antonio
Published: December 2004

Glutathione and other intracellular low molecular mass thiols act both as the major endogenous antioxidant and redox buffer system and, as recently highlighted, as an important regulator of cellular homeostasis. Such cellular functions are mediated by protein thiolation, a newly recognized post‐translational modification which involves the formation of mixed disulfides between GSH and key disulfide‐linked Cys residues in the native protein structure. It is also well known that thiol‐seeking heavy metals, such as mercury, cadmium and lead, may interfere in this regulatory system, thus disrupting the cellular functioning. To identify such mixed disulfides in order to investigate their biological role, 15 homo‐ and heterodimeric disulfides were prepared by air oxidation of binary mixtures containing cysteine, homocysteine, penicillamine, N‐acetylcysteine, N‐acetylpenicillamine and glutathione and their protonated molecules were characterized by mass spectrometry. Collisionally activated unimolecular decomposition of protonated homo‐ and heterodimeric disulfides generated by electrospray ionization gives rise to fission of the disulfide system both between the two sulfur atoms and across the CS bonds, to yield structurally specific fragments which allow one to define the structure of the compounds and to discriminate between isomeric compounds. Fission between the sulfur atoms yields a pair of RS+ ions and, in some cases, also the complementary fragments corresponding to the protonated amino acids. Fission across the CS bonds mainly occurs in the disulfides of N‐acetylcysteine and N‐acetylpenicillamine and gives rise to non‐S‐containing fragments formally similar to those obtained from some mercapturic acids. The complementary fragments, formally connected as RSS+ ions are also observed. Fragmentation of glutathione disulfides mainly shows the characteristic loss of the terminal γ‐linked glutamic acid and little, if any, fragmentation of the disulfide system. Copyright © 2004 John Wiley & Sons, Ltd.
Using mass spectrometry to probe the subtle differences in conformations of several cytochromes c in aqueous and methanol solutions
Authors: Wang Yao‐Fong , Ho May‐Yeh , Ho Yen‐Peng
Published: December 2004

We have detected, using electrospray mass spectrometry, minor changes in the H/D exchange rates in various solvents for cytochromes c obtained from five different species. We compared the exchange rates exhibited by these proteins by mixing horse cytochrome c with each of the other four species and monitoring their exchanges simultaneously by mass spectrometry. The use of horse cytochrome c as a reference allowed us to make very accurate comparisons of the small differences in hydrogen exchange rates among the various species. The exchange experiments were performed in water and methanol at several concentrations in an effort to determine whether the cytochromes c of these five species have different conformations in specific solvents, which would cause their exchange rates to differ. Therefore, monitoring the level of exchange as a function of time in both water and water–methanol mixtures is a method for detecting subtle structural changes of proteins in their native or unfolded intermediate states. Copyright © 2004 John Wiley & Sons, Ltd.
Regional phospholipid analysis of porcine lens membranes by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Estrada Rosendo , Yappert M. Cecilia
Published: December 2004

The applicability of matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) to the qualitative and quantitative analysis of most mammalian phospholipid (PL) classes was demonstrated in a crude extract of porcine lens membranes. When 2,5‐dihydroxybenzoic acid (DHB) was used as the matrix, positive‐ion spectra allowed the accurate quantification of phosphatidylcholines (PCs) and sphingomyelins (SMs). Other PLs such as phosphatidylethanolamines (PEs), phosphatidylethanolamine plasmalogens (PEps), phosphatidylethanolamine ethers (PEes) and phosphatidylserines (PSs), could also be detected, but their lower ionization efficiency led to negative errors in their quantification. Despite this limitation, it was possible to determine relative changes among PLs extracted from cortical and nuclear regions. Negative‐ion spectra were acquired with the use of p‐nitroaniline (PNA) as the matrix. Because neither PCs nor SMs produce negative ions, other PL classes can be analyzed selectively. The absolute quantification of the various PL classes detectable in negative‐ion spectra was also affected by differences in ionization efficiencies. However, the trends in compositional changes between cortical and nuclear‐fiber PLs were in agreement with those obtained by 31P NMR spectroscopy. MALDI‐TOFMS also offers the possibility of studying variations in the acyl‐chain distribution of the various species comprising each PL class. For porcine lenses, PCs, PEs and phosphatidylinositols (PIs) exhibited the greatest depletions in going from cortical to nuclear membranes. Among their individual species, those with two or more sites of unsaturation suffered the most significant reduction. Copyright © 2004 John Wiley & Sons, Ltd.
Different behavior of dextrans in positive‐ion and negative‐ion mass spectrometry
Authors: Čmelík Richard , Štikarovská Markéta , Chmelík Josef
Published: December 2004

A mass spectrometric (MS) comparative study of dextran samples using two different ionization techniques (matrix‐assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI)) in both positive‐ and negative‐ion modes is reported. The experiments were carried out with two polydisperse dextrans (1000 and 8800 Da) and isomaltotriose. In the positive‐ion mode, the expected alkali metal ion adducts of dextrans were observed in both techniques. In contrast, the expected preferential formation of deprotonated molecules [M − H]− was not confirmed in negative mode MALDI time‐of‐flight (TOF) MS, where the series of ions [Mx− H +42]− or [Mx+1− H − 120]−, coming either from some addition or fragmentation, were observed. In both ionization techniques, these ions formed the main distributions of dextrans in the negative‐ion mode. It seems that the negative molecular ions formed from the α1 → 6 linkage of polyglucose oligomers easily decompose, and the product ions [M − H − 120]− markedly dominate. The fragmentation experiments and especially the investigation of the fundamental role of the nozzle–skimmer potential in ESI‐MS supported our explanation of the observed behavior because its higher values caused higher fragmentation. The experiments with isomaltotriose excluded any addition of 42 Da during the MS procedures, which is not distinguishable from the loss of 120 Da in the case of polydisperse dextrans. MALDI‐TOFMS was found to be more sensitive for the detection of higher oligosaccharides and ESI‐MS more useful for structural studies. Copyright © 2004 John Wiley & Sons, Ltd.
Skill of a superensemble forecast over equatorial Southeast Asia
Authors: Mahmud Mastura
Published: December 2004

The performance of the multianalysis–multimodel superensemble weather forecast and its comparison with several other operational prediction models is investigated in this study for the Southeast Asian region. The superensemble technique has been proven to exhibit exceptional skills compared with individual or even ensemble average forecasts for parameters such as precipitation, motion and mass fields. Precipitation forecasts from the superensemble technique for the year of 2001 from this study show that its skill scores are better than the other global operational models employed. Its precipitation root‐mean‐square errors (RMSEs) are consistently lower than the other member models for the annual period examined. The equitable threat score, which indicates the association of the common rainfall threshold distribution between the forecast and observed best rainfall analysis from the Tropical Rainfall Measurement Mission and Special Sensor Microwave Imager dataset, is slightly underpredicted for light rain thresholds, but it still outperforms the other individual members or even the ensemble mean forecasts. Correlation analysis of the superensemble forecast against the observed is far higher than either the ensemble mean or the individual forecast member models and is maintained for up to 3‐day forecasts.

The motion field comparisons also exhibit that the superensemble forecasts are closer to the observed data than the other member models due to its low systematic errors at the 850 hPa pressure level. Both the precipitation and wind field analyses have shown that the Florida State University multianalysis–multimodel superensemble forecast provides the lowest RMSE, the highest correlation against the best‐observed data and lowest systematic errors compared with the other participating operational models. These forecasts have the potential to provide better daily weather predictions over the Southeast Asian region, particularly during the early northeast monsoon that often causes heavy rainfall in the equatorial part of the Southeast Asian region. Copyright © 2004 Royal Meteorological Society
Problematics in management theory and practice
Authors: Franklin Peter
Published: December 2004

This paper is concerned with the methodological and epistemological foundations of management theory. It develops the argument that management theory is essentially unreliable and in terms of a modernist or postmodernist epistemology, unable to offer any insights or understandings beyond those argued from the study of the specific instances of a specific case.

This dismal argument casts doubt on the philosophical validity of much formal management theory, and has serious implications about the use and application of theory by managers. Similarly, the argument can be used to cast doubt on the ethical stance of gurus and consultants that have allowed readers, users and clients to believe mistakenly that they have bought prescriptions, theories and models which have validity and wide applicability beyond the instances of a specific case or a specific industry.

Within the context of the philosophy of science, such scepticism about formal theory should be regarded as normal and healthy (Kuhn, 1970). Within the field of management, scepticism about formal theory offers managers the opportunity to seize the empty creative space ignored by the generalizing modernist solutions and thereby create, share and laud theory grounded in their own management practice. In this context, the impossibility of management theory based on the modernist paradigm should be seen as liberating rather than constraining.

The abandonment of management theories spawned by modernism and the false claims of science provides managers with an opportunity to escape the dictums of the gurus and the tired models entombed within the hard covers of hundreds of strategy textbooks. In brief, the end of modernism and the abandonment of the myth of a general theory of management offers managers a chance to rethink and repractise ways of understanding, choosing and creating different and hopefully more fulfilling futures.

Copyright © 2004 John Wiley & Sons, Ltd.
Attempts to more effectively target ethnic minority customers: the case of HSBC and its South Asian business unit in the UK
Authors: Chaudhry Shiv , Crick Dave
Published: December 2004

With some regions of the UK containing areas where the ethnic minority population has grown to become the ethnic majority, both personal and business banking needs of these communities provide areas of potential growth for financial institutions. Previous research has indicated that certain organizations do not understand particular cultural practices of customers within ethnic communities and have ineffectively targeted them.

This paper provides an insight into how a major bank has addressed the needs of particular ethnic communities. It reports on interview data with the Head of HSBC's South Asian Business Unit. The findings provide a contribution to the body of knowledge associated with the interface between subculture and financial institutions' marketing practices.

Copyright © 2004 John Wiley & Sons, Ltd.
Disparities in the recording of Parkinson's disease on death certificates
Authors: Pressley Joyce C. , Tang Ming‐Xin , Marder Karen , Cote Lucien J. , Mayeux Richard
Published: December 2004

Although little is known regarding potential socioeconomic or racial bias in the recording of Parkinson's disease (PD) on death certificates, studies of incidence, prevalence, and the etiology of PD frequently rely on this type of data. A national population‐based survey was linked to death certificate data to investigate the concordance of PD reported on death certificates for persons reporting PD during life. Logistic regression was used to identify independent factors associated with differential reporting of PD at death. Among decedents with PD reported during life, 54.8% had PD recorded on the death certificate. Nearly 70% of persons in higher income categories had PD recorded at death compared to 35.4% for those earning $10,000 or less. Age and gender adjusted odds of having PD recorded at death was 2.3 (1.1–3.9), for those with an annual income of $35,000 or more. Income differences remain significant in multivariable models after controlling for age, gender, race, census region, family size, rural residence, and number of chronic medical conditions. In conclusion, this study found socioeconomic bias in the reporting of PD at death. This bias is large enough to confound death certificate–based investigations of incidence, prevalence, and risk factors that differ across socioeconomic strata. © 2004 Movement Disorder Society
Levodopa‐dyskinesia incidence by age of Parkinson's disease onset
Authors: Kumar Neeraj , Van Gerpen Jay A. , Bower James H. , Ahlskog J. Eric
Published: December 2004

We assessed the 5‐year risk of levodopa‐induced dyskinesias by age of Parkinson's disease (PD) onset in a population‐based cohort. The medical records linkage system of the Rochester Epidemiology project was used to identify residents of Olmsted County, Minnesota, with incident PD for the period 1976 through 1990. In this population‐based study, the 5‐year dyskinesia incidence declined with age. With PD onset after 70 years of age, the incidence was 16%. With onset from 40 to 59 years of age, the incidence was higher at 50%. These incidence data may overestimate the functional importance, because patients with minimal or reversible dyskinesias were counted. © 2004 Movement Disorder Society
On the existence of incompressible current–vortex sheets: study of a linearized free boundary value problem
Authors: Trakhinin Yuri
Published: December 2004

We study the initial boundary value problem resulting from the linearization of the equations of ideal incompressible magnetohydrodynamics and the jump conditions on the hypersurface of tangential discontinuity (current–vortex sheet) about an unsteady piecewise smooth solution. Under some assumptions on the unperturbed flow, we prove an energy a priori estimate for the linearized problem. Since the so‐called loss of derivatives in the normal direction to the boundary takes place even for the constant coefficients linearized problem, for the variable coefficients problem and non‐planar current–vortex sheets the natural functional setting is provided by the anisotropic weighted Sobolev space W21,σ. The result of this paper is a necessary step to prove the local in time existence of solutions of the original non‐linear free boundary value problem. The uniqueness of the regular solution of this problem follows already from the a priori estimate we obtain for the linearized problem. Copyright © 2005 John Wiley & Sons, Ltd.
Assessing weak intramolecular donor–acceptor interactions using 1H117Sn J‐HMQC spectroscopy. Magnetic Resonance in Chemistry 2004; 42: 776–780
Authors: Biesemans Monique , Martins José C. , Jurkschat Klaus , Pieper Nicole , Seemeyer Stefan , Willem Rudolph
Published: December 2004

The original article to which this Corrigendum refers was published in Magnetic Resonance in Chemistry 2004; 42: 776–780
Psychometric properties and validation of the German‐language King's Health Questionnaire in women with stress urinary incontinence
Authors: Bjelic‐Radisic Vesna , Dorfer Martha , Tamussino Karl , Greimel Elfriede
Published: December 2004

Aims

The purpose of this study was to evaluate the psychometric properties of and validate the German‐language version of the King's Health Questionnaire (KHQ) in women with stress urinary incontinence (SUI).

Methods

A total of 145 women treated for stress incontinence with surgery or physiotherapy completed the the KHQ and the SF‐36 before and after treatment. Psychometric analyses of the quality of life (QoL) instruments determined the reliability (Cronbach's alpha), internal and external validity, and responsiveness of the KHQ subscales.

Results

The KHQ showed good internal consistency, content validity, and criterion validity as measured by correlation with scores on the SF‐36. Cronbach's alpha coefficient ranged from 0.76 to 0.86, indicating a high internal consistency of the subscales. Concerning criterion validity, correlations between the KHQ subscales and the SF‐36 were low to moderate. The highest correlation was found between the general health perception subscales of both questionnaires.

Conclusions

The results indicate good psychometric properties for the German‐language KHQ. © 2004 Wiley‐Liss, Inc.
Equivalent localization element for crack band approach to mesh‐sensitivity in microplane model
Authors: Červenka Jan , Bažant Zdeněk P. , Wierer Martin
Published: December 2004

The paper presents in detail a novel method for finite element analysis of materials undergoing strain‐softening damage based on the crack band concept. The method allows applying complex material models, such as the microplane model for concrete or rock, in finite element calculations with variable finite element sizes not smaller than the localized crack band width (corresponding to the material characteristic length). The method uses special localization elements in which a zone of characteristic size, undergoing strain softening, is coupled with layers (called ‘springs’) which undergo elastic unloading and are normal to the principal stress directions. Because of the coupling of strain‐softening zone with elastic layers, the computations of the microplane model need to be iterated in each finite element in each load step, which increases the computer time. Insensitivity of the proposed method to mesh size is demonstrated by numerical examples. Simulation of various experimental results is shown to give good agreement. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis and Crystal Structures of Two Cadmium Coordination Chain Polymers
Authors: He Xiang , Lu Can‐Zhong
Published: December 2004

Hydrothermal reactions of cadmium precursors with 2, 2′‐bipyridine, fumaric acid or NaN3 in basified aqueous solutions gave rise to two cadmium complexes [Cd(bipy)(fum)(H2O)]n (1), and [Cd(bipy)(μ1, 1‐N3)2]n (2) (fum = fumarate dianion), which were characterized by X‐ray crystallography. Complex [Cd(bipy)(fum)(H2O)]n (1) crystallizes in the orthorhombic system, space group Pbca, with a = 9.0488(8), b = 16.246(3), c = 19.810(4) Å, and Z = 8 while complex [Cd(bipy)(μ1, 1‐N3)2]n (2) in the monoclinic system, space group C2/c, with a = 12.378(3), b = 14.788(3), c = 6.6139(13) Å, β = 91.49(3)°, and Z = 4. The photoluminescence spectra for compounds 1 and 2 have also been studied.
Reaction of Hydroxyurea with Iron(III): Products and the Stoichiometry of the Redox Reaction
Authors: Kujundžić Nikola , Nigović Biljana , Sanković Krešimir
Published: December 2004

Products and reaction stoichiometry of the interaction between iron(III) and hydroxyurea (HU) in aqueous solutions were studied. Under condition of an excess of iron(III) over hydroxyurea, initially formed mono(hydroxyureato)iron(III) complex decomposed through redox processes, forming two moles of FeII, one mole of NH4+, one mole of CO2, and 0.5 mole of N2O per 1 mole of initially present HU. Hydroxyurea radical, H2N‐CO‐NHO?, was detected in the course of the reaction. The possible mechanism of the formation of the products is discussed and compared with that obtained for horseradish peroxidase mediated oxidation of hydroxyurea with hydrogen peroxide. The possibility of direct reaction of hydroxyurea with the iron center of protein R2 of the ribonucleotide reductase is proposed. The reaction examined may serve as a simple model for testing the suggested hydroxyurea like activity for chemical substances.
Synthese und Struktur hochfunktionalisierter 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaborole
Authors: Weber Lothar , Rausch A. , Stammler H.‐G. , Neumann B.
Published: December 2004

Eine Reihe von 2, 3‐Dihydro‐1H‐1, 3, 2‐diazaborolen wurde auf verschiedenen Wegen hergestellt. 1, 3‐Di‐tert‐butyl‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (7), 2‐Isobutyl‐1, 3‐bis(1‐cyclohexylethyl)‐1H‐1, 3, 2‐diazaborol (8), 1, 3‐Bis(1‐cyclohexylethyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (9) 1, 3‐Bis(1‐me‐thyl‐1‐phenyl‐propyl)‐2‐trimethylsilylmethyl‐1H‐1, 3, 2‐diazaborol (10) und 2‐Brom‐1, 3‐bis(1‐methyl‐1‐phenyl‐propyl)‐1H‐1, 3, 2‐diazaborol (11) entstehen durch Reaktion der entsprechenden 1, 4‐Diazabutadiene mit den Boranen Me3SiCH2BBr2, iBuBBr2 bzw. BBr3 und die nachfolgende Reduktion der resultierenden Boroliumsalze $\rm [R^{1}\overline{N=CH-CH=N(R^{1})B}R^{2}Br]Br$ [R1 = tBu, Me(cHex)CH, [Me(Et)Ph]C; R2 = Me3SiCH2, iBu, Br] mit Natriumamalgam. Reaktion der 2‐Brom‐1, 3, 2‐diazaborole 11 und 12 mit Silbercyanid liefert die 2‐Cyano‐1, 3, 2‐diazaborole 13 und 14. Die Alkylierung von 12 mit Isobutyllithium stellt eine Alternativsynthese für Verbindung 8 dar, während äquimolare Mengen 13 mit Isobutyllithium zur Bildung von 15 führen. Die neuen Verbindungen wurden durch Elementaranalysen sowie 1H‐, 13C‐, 11B‐NMR‐, IR‐ und Massenspektren charakterisiert. Die Molekülstrukturen der Verbindungen 7 und meso‐10 wurden durch Röntgenbeugung ermittelt.
Tetraazadibora[3, 3]paracyclophane
Authors: Paetzold Peter , Welling‐Osterloh Ute , Englert Ulli
Published: December 2004

Starting from the para‐phenylenediamine derivative HN(SiMe3)‐C6H4‐NH(SiMe3), a lithiation and subsequent borylation give [(MeO)2B]N(SiMe3)‐C6H4‐N(SiMe3)[B(OMe)2] (1), the hydridation of which yields Li2[(H3B)N(SiMe3)‐C6H4‐N(SiMe3)(BH3)] (2). Applying ZrCl4 upon 2 initiates a condensation to give the title compound [‐N(SiMe3)‐p‐C6H4‐N(SiMe3)‐BH‐]2, a hetero[3, 3]paracyclophane with two N‐B‐N chains that connect the para‐phenylene units. The product 3 crystallizes in the orthorhombic space group P212121.
First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3
Authors: Roßmeier Thomas , Korber Nikolaus
Published: December 2004

The compound [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3 (1) was prepared by the reaction of Na[Co(C2B9H11)2] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C2B9H11)2]‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite [{NH4(NH3)4}+(μ‐NH3)2] cationic chain, which is formed by [NH4(NH3)4]+ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).