bluuebunny/crossref_metadata_2025_split huggingface dataset:
Llandovery Crinoidea of the British Isles, including description of a new species from the Kilbride Formation (Telychian) of western Ireland
Authors: Donovan Stephen K. , Harper David A. T. 
Published: March 2003

AbstractA new species of cladid(?) crinoid, Segmentocolumnus (col.) clarksoni, based on distinctive, disarticulated stem material, is described from the Upper Llandovery Kilbride Formation. Hitherto, this unit has yielded two taxa based on single, nearly complete crinoids. In contrast, S. (col.) clarksoni is known from numerous specimens, including common long pentagonal, pentameric, heteromorphic pluricolumnals with symplectial articulations, broad pentagonal lumina and narrow claustra. A related morphospecies is known from the Ashgill (Upper Ordovician) of Ireland. The fossil echinoderms of the Llandovery (Lower Silurian) are poorly known globally. Where present in this interval, echinoderms are more commonly preserved as disarticulated ossicles and rarely as complete specimens. Complete crinoids have now been identified from nine horizons in the Llandovery of the British Isles, making this one of the better known pelmatozoan faunas from this time interval. However, only two of these occurrences have yielded as many as five or more identifiable taxa. Seven of the nine occurrences are Upper Llandovery (Telychian). Genera are typical of the Silurian or (Upper Ordovician + Silurian); the only remnant Ashgill taxon that did not survive the Llandovery was the morphogenus Segmentocolumnus (col.) Donovan, an ‘extinction’ that probably owes more to taxonomic method than any evolutionary pattern. Copyright © 2003 John Wiley & Sons, Ltd.
The importance of the dominant hemisphere in the organization of bimanual movements
Authors: Serrien Deborah J. , Cassidy Michael J. , Brown Peter 
Published: March 2003

AbstractThe successful control of upper limb movements is an essential skill of the human motor system. Yet, the neural organization of bimanual actions remains an issue of debate. Their control can be directed from both hemispheres, or, coordinated motion might be organized from the dominant (left) hemisphere. In order to unravel the neural mechanisms of bimanual behavior, we analyzed the standard task‐related and directed coherence between EEG signals picked up over the primary sensorimotor cortices in right‐handed subjects during unimanual as well as bimanual in‐phase (symmetrical) and anti‐phase (asymmetrical) movements. The interhemispheric coherence in the β frequency band (>13–30 Hz) was increased in both unimanual and bimanual patterns, compared to rest. During unimanual actions, the drive in the β band from one primary sensorimotor cortex to the other was greater during movement of the contralateral as opposed to ipsilateral hand. In contrast, during bimanual actions, the drive from the dominant to the non‐dominant primary sensorimotor cortex prevailed, unless task constraints induced by an external perturbation resulted in a substantial uncoupling of the hand movements, when interhemispheric coherence would also drop. Together, these results suggest that the contralateral hemisphere predominantly organizes unimanual movements, whereas coupled bimanual movements are mainly controlled from the dominant hemisphere. The close association between changes in interhemispheric coupling and behavioral performance indicates that synchronization of neural activity in the β band is exploited for the control of goal‐directed movement. Hum. Brain Mapping 18:296–305, 2003. © 2003 Wiley‐Liss, Inc.
Medical care use and selection in a social health insurance with an equalization fund: evidence from Colombia
Authors: Trujillo Antonio J. 
Published: March 2003

AbstractThis paper studies the relationship between health status and insurance participation, and between insurance status and medical use in the context of a social health insurance with an equalization fund (SHIEF). Under this system, revenues from a mandatory payroll tax are collected into a single pool (equalization fund) that reimburses for‐profit insurance companies according to a capitated formula. Although competition should induce insurers to control costs without reducing the quality of service necessary to attract consumers, limitations in the capitation formula might induce insurers to select against bad risks, and limitations in the contribution system might induce more healthy individuals to evade enrollment. A three‐equation model having social health insurance, private health insurance, and using medical services is estimated using a 1997 Colombian household survey. Consistent with similar studies, participation in SHIEF increases medical care use. On the other hand, the evidence on selection is somewhat mixed: individuals who report good health status are more likely to participate in SHIEF, while those without a chronic condition are less likely to participate in SHIEF. Copyright © 2002 John Wiley & Sons, Ltd.
Reactions of α,β‐Enones with Diazo Compounds, Part 3
Authors: Anaç Olcay , Daut Özdemir Ayşe , Sezer Özkan 
Published: March 2003

AbstractCarbonyl ylides arising from ethyl acetodiazoacetate/dimethyl diazomalonate and α,β‐enones with mainly s‐cis conformations underwent disrotatory cyclization to produce dihydrofuran derivatives. This process proved to be sensitive to steric effects. The corresponding ylides arising from rather s‐trans α,β‐enals yielded dioxole derivatives. The mechanisms of the reactions are discussed.
The Syntheses of Cyclic Spermine Alkaloids: Analogues of Buchnerine and Budmunchiamine C
Authors: Li Yi , Hesse Manfred 
Published: March 2003

AbstractThe syntheses of two macrocyclic spermine alkaloids, analogues 1 and 2 of budmunchiamine C and buchnerine, in which N,N′‐bis(2‐aminoethyl)hexane‐1,6‐diamine (PA 262; 4) replaces spermine as polyamine backbone, were accomplished by two different methods. The first synthetic approach was based on a metal‐template intramolecular amidation of tetraamino esters prepared from a Michael addition of protected PA 262 10 to ethyl hexadec‐2‐ynoate (12) and ethyl prop‐2‐ynoate 17, respectively (see Schemes 4 and 5, resp.). The consecutive Michael addition of ethane‐1,2‐diamine to unsaturated esters and aminolysis was employed in the second synthetic approach to prepare the precursors 23 and 24 (Scheme 6). The macrocyclic lactams were then constructed by macrocyclization of sulfonamido derivatives 25 and 26 in DMF with Cs2CO3 as catalyst.
A New Family of C3‐Symmetrical Carbohydrate Receptors
Authors: Welti Roger , Diederich François 
Published: March 2003

AbstractThe formation of the new optically active C3‐symmetrical receptors (S,S,S)‐2–4 (Fig. 1), incorporating 1,3,5‐triphenylbenzene and 1,3,5‐tris(phenylethynyl)benzene platforms as ‘floors' and ‘ceilings', is described. The tris(phenylethynyl)benzene derivatives 9 and (S,S,S)‐10 (Scheme 1) for the three‐fold peptide coupling to yield the macrocyclic skeletons (Scheme 2) were prepared starting from 1,3,5‐triethynylbenzene by the Sonogashira cross‐coupling reaction. The optical rotations of the three macrocycles (S,S,S)‐2–4, two of which ((S,S,S)‐2 and (S,S,S)‐3) are constitutional isomers, differ significantly, which is explained by differential twists induced into the macrocyclic skeletons by the leucine spacer in these bridges. 1 : 1 Host–guest complexes of (S,S,S)‐2–4 with octyl glucosides (Fig. 3) in CDCl3 are of modest stability (Ka≤270 M−1 at 300 K). In these complexes, the monosaccharides are most probably nesting on one of the H‐bonding faces of the receptor rather than being accommodated in the cavity.
Treatment of acute lymphoblastic leukemia in Hong Kong children: HKALL 93 study
Authors: LI C. K. , Chik K. W. , Chan G. C. F. , Yuen H. L. , Lee A. C. W. , Keung Li C. , Shing M. M. K. , Ha S. Y. , Luk C. W. , Ling S. C. , Cheung A. Y. K. 
Published: March 2003

AbstractA population‐based multicentre study for childhood acute lymphoblastic leukemia (ALL) was conducted in Hong Kong from 1993 to 1997. One hundred and forty‐five newly diagnosed ALL patients were treated by the HKALL 93 protocol. Patients were stratified into three risk groups according to age, presenting white cell count, immunophenotyping and cytogenetic study. The patients received the same induction and early and late intensification at week 5 and week 20. Fifty‐eight standard risk (SR) patients received regular intrathecal methotrexate as CNS preventive therapy, while 49 intermediate risk (IR) patients received high dose intravenous methotrexate and regular intrathecal methotrexate. Thirty‐eight high risk (HR) patients were treated with prophylactic cranial irradiation and an additional intensification block at week 35. The induction remission rate was 97.2% with 2% induction death. Two patients died during first complete remission. Relapse occurred in 20.7, 42.9 and 42.1% of SR, IR and HR patients respectively. By multivariate logistic regression, age≥10 years and white cell count≥100×109/l were the two significant variables accounting for mortality. The 5‐year overall and event‐free survival of the whole group was 81.3 and 62.6% respectively. According to risk groups, the event‐free survival was 79, 49 and 61% for SR, IR and HR patients respectively, while the overall survival was 96, 73 and 68% for SR, IR and HR patients respectively. In conclusion, the treatment protocol had low treatment‐related mortality but was associated with a rather high relapse rate, especially in IR patients. Salvage therapy achieved sustained second remission in some patients. More intensive treatment especially a late intensification is required to improve the outcome. Copyright © 2002 John Wiley & Sons, Ltd.
Application of kinematic wave theory for predicting flash flood hazards on coupled alluvial fan–piedmont plain landforms
Authors: Mukhopadhyay Biswajit , Cornelius Joe , Zehner Warren 
Published: March 2003

AbstractA rainstorm that caused a severe flash flood on the piedmont plain at the toe positions of two alluvial fans located to the west of the Organ Mountains in Dona Ana County, New Mexico, USA, is analysed. The space–time distributions of rainfall are evaluated from the Next Generation Weather Radar (NEXRAD) and overland flow is modelled as kinematic wave. The spatial distribution of rainfall shows a topographic control. The greatest rainfall depth, duration, and intensity occurred at the higher elevation mountain slopes and decreased with decreasing elevation from the alluvial fans to the piedmont plain. The alluvial fan–piedmont plain system is modelled by coupling divergent and rectangular overland flow planes. Explicit finite difference approximations, hybridized with the analytical method of characteristics, are made to the kinematic wave equations to account for the spatial and temporal distribution of the rainfall and variable boundary conditions. Simulation results indicate that sheet‐flow floodwater elevations rise (1) in a nonlinear fashion from the apex to toe positions of the alluvial fans, and (2) near linearly from the toe positions of the alluvial fans onto the piedmont plains with the formation of kinematic shocks near the middle to the upstream end of the plane at times between the initiation of the rainstorm and the time of concentration of the plane. Thus, the maximum flooding occurs at the middle or upstream sections of the piedmont plains regardless of the pattern of space–time variability of rainfall. These results are in agreement with observed geomorphologic features suggesting that piedmont plains are naturally flood‐prone areas. This case study demonstrates that flood hazards on piedmont plains can exceed those on alluvial fans. The models presented in this study suggest that the flood hazard zones on coupled alluvial fan–piedmont plain landforms should be delineated transverse to the flow directions, as opposed to the flood hazard zones with boundaries in the longitudinal direction of the axis of an alluvial fan. Copyright © 2003 John Wiley & Sons, Ltd.
Perfluorohexyloctane (F6H8) induces structural modifications and increases apoptosis in rat primary retinal cultures
Authors: Malchiodi‐Albedi F. , Matteucci A. , Formisano G. , Paradisi S. , Carnovale‐Scalzo G. , Perilli R. , Scorcia G. , Caiazza S. 
Published: March 2003

AbstractThe effects of perfluorohexyloctane (F6H8), recently investigated as a long‐term artificial vitreous substitute, were studied in vitro, with the use of rat retinal cultures seeded on microporous inserts that allow the cell layer to be in contact with the material to be tested, on the apical side, and with the nutrient medium, on the basal side. After 72 h of treatment with F6H8, retinal cultures lost the characteristic two‐layered organization with glial cells at the bottom and neuronal cells on top of them. They appeared to be composed of only one layer of polyhedrical, flattened, and disconnected cells. TUNEL assay revealed an evident increase in the percentage of apoptotic cells in F6H8‐treated cultures (30.1 ± 4.5), compared to control (10.3 ± 2.6) and perfluoroctane‐treated cultures (10.1 ± 1.7). Immunolabeling of MAP‐2, a protein of neuronal cytoskeleton, evidenced a marked loss of neurites. The results suggest that F6H8 is harmful to retinal cells in vitro and can therefore be potentially noxious to the retina as an artificial vitreous substitute. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 65B: 133–136, 2003
Tobramycin and Gentamycin elution analysis between two in situ polymerizable orthopedic composites
Authors: DiCicco M. , Duong T. , Chu A. , Jansen S. A. 
Published: March 2003

AbstractThis research analyzed Tobramycin and Gentamycin elution characteristics for two antibiotic‐impregnated bone composites: PMMA‐based Simplex P® and the novel, hybrid, bioactive, CORTOSS™. Experimental results were correlated with composite hydrophilicity and antibiotic phase partitioning behaviors. The phase partitioning experiment was conducted to understand antibiotic solubility in aqueous environments. By comparing experimental results with calculated data, antibiotic release behavior was predicted. Total Tobramycin elution percentages from CORTOSS and Simplex P were 12.5 and 6.4%, respectively. Total Gentamycin elution percentages from CORTOSS and Simplex P were 6.95 and 10.17%, respectively. Phase partitioning data indicate 100% of Tobramycin remains in aqueous phases, being extremely hydrophilic. This is supported by its calculated theoretical value (log P = − 7.32). Results suggest that Tobramycin elution can be attributed to composite hydrophilicity as well as its high degree of hydrophilicity. Fifteen percent of Gentamycin distributes in hydrophobic phases (log P = − 4.22). Despite a lower Gentamycin hydrophilicity, its release was affected by its complexation with polar salts in the leaching buffer, thereby increasing its elution potential, making it appreciably water soluble. CORTOSS is more hydrophilic; therefore the migration of aqueous liquids into the polymer network of CORTOSS facilitates greater antibiotic elution compared with hydrophobic Simplex P. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 65B: 137–149, 2003
Effect of extent of motion and type of load on the wear of polyethylene in a biaxial hip simulator
Authors: Saikko Vesa , Calonius Olof , Keränen Jaakko 
Published: March 2003

AbstractThe most commonly used wear test device for prosthetic hip joints is the so‐called biaxial rocking motion (BRM) design. The design has been criticized for its excessive sliding distance per cycle. The design was modified so that the extent of motion was reduced from 46 to 23°, and comparative tests were run with the use of 1‐kN static load. The present authors have earlier used 1‐kN static load with good results. To further confirm this finding, additional, comparative tests were run with double‐peak dynamic load and 46° extent of motion. All three tests (46°/static, 23°/static and 46°/dynamic), were done with conventional ultra‐high‐molecular‐weight polyethylene acetabular cups against polished CoCr femoral heads in diluted calf serum lubricant. In all tests, the principal cup wear mechanism was adhesive, manifested as burnishing. With respect to wear particles, those produced in the 46°/dynamic test showed the lowest resemblance to particles isolated from periprosthetic tissues. The 46°/dynamic test produced a mean wear rate 43% higher than 46°/static, whereas the 46°/static and 23°/static tests produced almost identical values. The results indicated that the 46° extent of motion and dynamic load may not always be the optimal combination in BRM tests. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 65B: 186–192, 2003
Low temperature‐induced dimerization of the bovine sperm serine protease, BSp66
Authors: Cesari Andreina , Cacciato Claudio Santiago , De Castro Rosana Esther , Sánchez Jorge Julián 
Published: March 2003

AbstractBSp120 and BSp66 are trypsin‐like serine proteases from bovine spermatozoa. The former is active in cryopreserved sperm samples while the latter shows proteolytic activity in recently obtained fresh sperm. Both proteases are immunologically related and co‐localize in the apical portion of the sperm head. In Western blots with specific antibodies, sperm samples incubated with reducing agents showed a decrease in the amount of BSp120, while BSp66 was detected with both anti‐BSp120 and anti‐BSp66 antibodies. BSp120 was evident in frozen intact spermatozoa after 60 days of semen cryopreservation and the kinetic of appearance of this protein was coincident with the decrease in the amount of BSp66. Identical results were obtained by freezing sperm extracts from fresh semen at −20°C. Our results suggest that BSp120 results from disulfide bond‐dimerization of BSp66 and that this process may be induced by temperatures below zero in both intact spermatozoa and in sperm extracts. J. Cell. Biochem. 88: 1057–1065, 2003. © 2003 Wiley‐Liss, Inc.
Cloning and functional characterization of GNPI2, a novel human homolog of glucosamine‐6‐phosphate isomerase/oscillin
Authors: Zhang Jia , Zhang Weiping , Zou Dajin , Chen Guoyou , Wan Tao , Li Nan , Cao Xuetao 
Published: March 2003

AbstractThe enzyme, glucosamine‐6‐phosphate isomerase (GNPI) or deaminase (GNPDA) (EC 5.3.1.10), catalyzes the conversion of GNP to fructose‐6‐phosphate and ammonia, with an aldo/keto isomerization and an amination/deamination. A hamster sperm‐derived protein (Oscillin) with high similarity to bacterial GNPI has been proved to be capable of inducing calcium oscillation in eggs at fertilization. GNPI/Oscillin was supposed to be an important factor in starting embryonic development. From the cDNA library of human dendritic cells (DC), we isolated a novel full‐length cDNA encoding a 276‐amino acid‐residue protein that shares high homology with human GNPI/Oscillin. So, the novel molecule is named as GNPI2. The GNPI2 gene consists of seven exons and six introns. It is mapped to chromosome 4. Northern blot analysis indicated that the tissue distribution of GNPI2 mRNA is different from that of human GNPI or Oscillin mRNA. GNPI2 is ubiquitously expressed in most of human tissues with high expression in testis, ovary, placenta, and heart. Like GNPI, the recombinant GNPI2 has been proved to have the enzymatic activity to catalyze the conversion of GNP to fructose‐6‐phosphate. Our results indicated that GNPI2 is a novel protein with definite function as a GNPI. J. Cell. Biochem. 88: 932–940, 2003. © 2003 Wiley‐Liss, Inc.
Modulation of PECAM‐1 expression and alternative splicing during differentiation and activation of hematopoietic cells
Authors: Wang Yongji , Su Xiaojing , Sorenson Christine M. , Sheibani Nader 
Published: March 2003

AbstractPECAM‐1 (CD31) is a member of immunoglobulin gene superfamily, which is highly expressed on the surface of endothelial cells and at moderate levels on hematopoietic cells. Hematopoietic cells and platelets, like endothelial cells, express multiple isoforms of PECAM‐1. However, the identity and physiological role of these isoforms during hematopoiesis remains largely unknown. Here we demonstrate that PECAM‐1 expression is dramatically up regulated upon phorbol myristate acetate (PMA) or transforming growth factor (TGF)‐β1‐mediated differentiation of leukemic HEL and U937 cells. The level of PECAM‐1 expression did not significantly change during activation of Jurkat T cells by PMA or phytohaemagglutinin (PHA). Utilizing RT‐PCR and DNA sequencing analysis, we show that the expression of PECAM‐1 isoforms changes in a cell‐type and lineage specific manner during cellular differentiation and activation. We identified a number of novel PECAM‐1 isoforms previously not detected in the endothelium. These results demonstrate that regulated expression of PECAM‐1 and its exonic inclusion/exclusion occurs during differentiation and/or activation of hematopoietic cells. Thus, different PECAM‐1 isoforms may play important roles in generation of hematopoietic cells and their potential interactions with vascular endothelium. J. Cell. Biochem. 88: 1012–1024, 2003. © 2003 Wiley‐Liss, Inc.
Human melanoma TrkC: Its association with a purine‐analog‐sensitive kinase activity
Authors: Marchetti Dario , Murry Brian , Galjour Jennifer , Wilke‐Greiter Andrea 
Published: March 2003

AbstractThe various members of the Trk tyrosine kinase family and p75 neurotrophin receptor (p75NTR) have been identified as signaling receptors for the structurally related members of the neurotrophins (NT) family. We have previously reported that NT treatment of murine and human brain‐metastatic melanoma cells affects their invasive capacities and increases the production of extracellular‐matrix degradative enzymes. These cells express aberrant levels of functional p75NTR and TrkC, the putative high‐affinity receptor for the neurotrophin NT‐3. Here we demonstrate that, by using sensitive immune‐complex kinase assays in human brain‐metastatic (70W) melanoma cells, TrkC receptors associate with a kinase activity exhibiting a dose‐dependent susceptibility to inhibition by the purine‐analogs 6‐thioguanine and 2‐aminopurine. The activity of this purine‐analog‐sensitive kinase (PASK) was induced by NT‐3 in a time‐dependent fashion, phosphorylating exogenous myelin basic protein (MBP) but not denatured enolase. It is similar to the one reported to relate with p75NTR and TrkA receptors and stimulated by the prototypic NT, nerve growth factor. Thus, PASKs may represent unique signaling components common to NT receptors that could engage joint downstream signaling effectors in brain‐metastatic melanoma.
Vertical spectrum of the C2H system. An open shell (SC)2‐CAS‐SDCI study
Authors: Pitarch‐Ruiz José , Sánchez‐Marín José , Maynau Daniel 
Published: March 2003

AbstractThe open shell (SC)2‐CAS‐SDCI method along with a basis set of atomic natural orbitals (ANO) has been applied for calculating the main ionization potentials of acetylene, as well as the manifold of excited states of the different symmetries up to 32 eV. In this method, the single and double excitations of a CAS space are generated and the corresponding CI matrix is corrected by means of the (SC)2 procedure that cancels the size‐extensivity error and adds some high order contributions. The mean absolute error for the outer‐valence X 2Πu(1π), A 2Σ(3σ), and B 2Σ(2σ) states, and the inner‐valence C 2Σ(2σ) state is 0.1 eV. The excited states of C2H corresponding to the Σ, Σ, Πg, Πu, Δg, and Δu symmetries are reported and their composition is discussed. The results are thoroughly compared to the best available multireference CI calculations. Recent multichannel CI results by Wells and Lucchese [J Chem Phys 1999, 110, 6365] have been used also as a guide for the discussion of the results. Discrepancies in the description of many multiconfigurational states by means of the (SC)2‐CAS‐SDCI wave function as compared to previous large MR‐CI calculations are significant and are, consequently, remarked on. A large mixing of the 3σ and 2σ processes is found in the A 2Σ and C 2Σ states, provided that the basis set is augmented with Rydberg functions. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 609–617, 2003