bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative study of methods for the quantification of biofilm on complete dentures
Authors: Paranhos Helena de Freitas Oliveira , Silva Cláudia Helena Lovato da
Published: April 2005

This study compared the application and reliability of 4 methods for biofilm quantification (computerized, paper-weighing, point-counting, and planimetric) in complete dentures, verifying the correlation between them. The internal surfaces of 62 complete dentures were stained (5% erythrosine) and photographed. The slides were projected on paper, and the areas (total and biofilm-covered) were outlined with a pencil. These areas were measured with an equidistant point grid (point-counting method), a digital planimeter (planimetric method), and for the paper weighing method they were cut and weighed with a precision scale. For the computerized method, ImageTool software was used. In order to perform a validation test of the methods, all of them were applied to slide projections of geometric figures with known dimensions. The correlation tests showed high correlation values (r = 0.82 to 0.99) among the methods. The validation test (ANOVA) showed no statistically significant differences among the values obtained from the measurement of figures using all four quantitative methods and the real dimensions of these geometric figures. Quantitative methods were efficient and reliable for measuring quantity of biofilm in complete dentures, and may be useful in experimental studies on the efficacy of hygiene products. The computerized method was fast and easy to perform.
New bone formation in the female rabbit tibia
Authors: Colmanetti Alexandre , Pereira Kleber Fernando , Chopard Renato Paulo
Published: April 2005

The current study aims to evaluate the new bone formation in polyvinylpyrrolidone (PVP) grafts inserted into the tibia of ten female rabbits. The animals were submitted to oophorectomy in order to induce an osteopenic condition and densitometrically analyzed at the beginning of the experiment, at three months and at seven months. During the 16 weeks of osseointegration, the animals were submitted to subcutaneous injections of three bone markers at one-week intervals, four weeks for each. Before the third densitometric analysis, the animals were sacrificed and material was collected for histological evaluation, in which osteoid formations and mineralized bone tissue were observed surrounding the grafts, even within the medullary cavity. Only small quantities of new bone were found in the osteopenic animals, indicating the high osteocondutivity of PVP and its efficacy in inducing osteopenia. Among the samples with no graft, a high level of disorganization of the material was observed in the oophorectomized group, confirming the efficacy of oophorectomy.
Impact of Iowa Case Management on Provisions of Social Support for Substance Abuse Clients
Authors: Sarrazin Mary Vaughan , Hall James A.
Published: April 2005

Substance abuse can have a devastating effect on the social support networks of individuals. This article describes the impact of a comprehensive model of case management on substance abuse treatment clients’ perceptions of social support. Social support was defined using a well-documented typology identifying six provisions for social support. The Iowa Case Management Project (ICMP) for Rural Drug Abuse was a randomized clinical trial using a longitudinal design. Clients were recruited from the residential treatment program of one rural Midwestern substance abuse treatment agency and were randomly assigned to one of three experimental conditions that received case management according to a strengths-based model, or to a control group. Client perceptions of social support were measured up to 12 months after treatment initiation. Results indicated that case management positively impacted overall perceptions of social support subsequent to treatment admission, as well as perceptions of support in two of the six provisions of support. Reassurances of worth, which is the recognition of one’s competence, skills, and value by others, and attachment, which reflects close emotional bonds with others, were both significantly improved for clients who received case management. However, the effectiveness of case management in improving social support appears to be limited to clients who are married or have significant partners.
Interspecific competition and rarity in mudsnails: feeding interactions between and withinHydrobia acuta neglectaand sympatricHydrobiaspecies
Authors: Barnes R.S.K.
Published: April 2005

Using production of faecal pellets as a proxy for feeding rate, possible reciprocal effects of the widespread and abundant mudsnailsHydrobia ulvaeandHydrobia ventrosaon the rareHydrobia acuta neglectawere investigated under the sea‐water salinity conditions in which all three species occur naturally in East Anglia, UK.

Over a density range equivalent to 1000–34 000 m−2,H. acutaandH. ventrosa(though notH. ulvae) at some point displayed an intraspecific reduction in egestion with increase in density. ForH. acuta, every 5000 extra snails above a threshold of 16 000 m−2reduced egestion by up to 8%; and forH. ventrosa, every 5000 extra snails above a threshold of 8000 m−2reduced egestion by an average 7%.

Keeping the density of one test species constant at 4000 m−2whilst varying that of a sympatric one from 0 up to 30 000 m−2indicates thatH. ulvaehas a marked effect onH. acutaat all densities, decreasing its egestion by 10% for every 5000 m−2H. ulvaealso present, but thatH. acutahas no such reciprocal effect onH. ulvae.H. ventrosahad no effect on egestion inH. acuta, althoughH. acutadid have some minor effect onH. ventrosa, on average decreasing its egestion by 3% for every 5000 m−2H. acutapresent.

The intensity of intraspecific competition withinH. acuta, therefore, exceeds that exerted onH. acutabyH. ventrosa, and likewise intraspecific effects withinH. ventrosagenerally outweigh any interspecific effect fromH. acuta. The effect ofH. ulvaeonH. acuta, however, exceeds that intraspecifically withinH. acuta.

These results are discussed in relation to the rarity ofH. acuta neglecta.

Copyright © 2005 John Wiley & Sons, Ltd.
The relationship of records in multiple databases to their usage or citedness
Authors: Hood William Wellesley , Wilson Concepción Shimizu
Published: April 2005

Papers in journals are indexed in bibliographic databases in varying degrees of overlap. The question has been raised as to whether papers that appear in multiple databases (highly overlapping) are in any way more significant (such as being more highly cited) than papers that are indexed in few databases. This paper uses a dataset from fuzzy set theory to compare low overlap papers with high overlap ones, and finds that more highly overlapping papers are in fact more highly cited.
Somatic transgenesis in the avian model system
Authors: Ishii Yasuo , Mikawa Takashi
Published: April 2005

The chick embryo is a versatile model system, in which classical embryology can be combined with modern molecular approaches. In the last two decades, several efficient methods have been developed to introduce exogenous genes into the chick embryo. These techniques allow alteration of gene expression levels in a spatially and temporally restricted manner, thereby circumventing embryonic lethality and/or eliminating secondary effects in other tissues. Here, we present the current status of avian somatic transgenic techniques, focusing on electroporation and retrovirus‐mediated gene transfer. Electroporation allows quick and efficient gain‐of‐function studies based on transient misexpression of genes. Retroviral vectors, which are capable of integrating exogenous genes into the host chromosome, permit analysis of long‐term effects of gene misexpression. The variety of methods available for somatic transgenesis, along with the recent completion of the chicken genome, are transforming the chick embryo into one of the most attractive model systems to examine function of genes that are important for embryonic development. Birth Defects Research (Part C) 75:19–27, 2005. © 2005 Wiley‐Liss, Inc.
Epigenetic reprogramming throughout preimplantation development and consequences for assisted reproductive technologies
Authors: Wrenzycki Christine , Herrmann Doris , Lucas‐Hahn Andrea , Gebert Claudia , Korsawe Karin , Lemme Erika , Carnwath Joseph W. , Niemann Heiner
Published: April 2005

Knowledge about preimplantation development is important both for basic reproductive biology and for practical applications, including livestock breeding and regenerative medicine. During preimplantation development, epigenetic modifications such as DNA methylation and histone modifications are involved in the regulation of imprinted and nonimprinted genes, in the initiation of X chromosome inactivation, and the adjustment of telomere length. The underlying events are particularly vulnerable to external factors. Characterization of expression profiles in in vivo–derived embryos of different developmental stages and understanding the mechanisms and dynamics underlying the reprogramming process are the first steps towards the analysis of the complex gene regulatory networks. They provide a baseline for the analysis of manipulated embryos of all mammalian species, including humans, to improve embryo technologies and related therapeutic applications. Birth Defects Research (Part C) 75:1–9, 2005. © 2005 Wiley‐Liss, Inc.
Platelet function in acute experimental pancreatitis induced by ischaemia–reperfusion
Authors: Hackert T , Pfeil D , Hartwig W , Gebhard M M , Büchler M W , Werner J
Published: April 2005

Background

Ischaemia–reperfusion (IR)-associated microcirculatory changes play a major role in acute post-transplantation pancreatitis. The pathophysiological role of platelets in these events is unknown. The aim of this study was to examine platelet adhesion and function during early reperfusion after pancreatic ischaemia.

Methods

Rats were subjected to warm pancreatic ischaemia by cross-clamping of the pancreatic vessels for 1 h. After 1 h of reperfusion, platelet–endothelium interaction was evaluated after platelet separation and staining by fluorescence microscopy. Amylase levels and pancreatic histology were evaluated 24 h after reperfusion. Animals treated according to an identical protocol, but without ischaemia, served as controls.

Results

Mild pancreatitis had developed by 24 h after IR; serum amylase levels were significantly higher than those in control animals. The numbers of adherent platelets in capillaries and venules were significantly increased, and platelet velocity in capillaries was significantly decreased, in the IR group compared with controls. There was significantly more oedema and inflammation in pancreatic tissue after IR.

Conclusion

Warm ischaemia for 1 h followed by reperfusion for 24 h caused mild pancreatitis in this experimental model. The pancreatic microcirculation was characterized by pronounced platelet–endothelium interaction in capillaries and venules. These results suggest that platelet activation may play an important role in acute post-transplantation pancreatitis.
Numerical study of influences of buoyancy and solutal Marangoni convection on flow structures in a germanium‐silicon floating zone
Authors: Lin K. , Dold P. , Benz K. W.
Published: April 2005

This paper presents a numerical study of Marangoni flows in a floating zone of germanium‐silicon crystals, which was performed by using a commercial finite element program FIDADTM. The numerical results point out that for fluids with a small Pr number the influence of buoyancy forces cannot be ignored in the numerical model. Furthermore, the competition between the thermocapillary (TC) and solutocapillary (SC) flows in the floating zones was qualitatively examined. If the TC flow is as strong as that in the Si‐rich floating zone, the SC flow may be restricted to the bottom area near the free surface. Otherwise, the SC flow may overcome the TC flow and induce a surface transfer of species. The numerical predictions agree well with the previous experiment results. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Manifestation of microcrystalline structure in transport properties of p‐quinquophenyl films
Authors: Tkaczyk S. , Kityk I. V. , Ebothé J.
Published: April 2005

The electrical conductivity measurements of the p‐quinquephenyl films possessing microcrystallite structure are done at temperature between 10 K–300 K. The investigated film thickness varies within 0.2–2.5 µm. The measurements were performed with Al(Au) electrodes for the films deposited by spin coating in argon atmosphere on glass substrates. The molecular dynamics simulations as well as quantum chemical calculations have shown that three different mechanisms contribute to the observed electrical feature, which are: the conductivity originated from proper crystalline states; this of the amorphous‐like inter‐grain region and the one created in the grain boarder interfaces. Comparing the experimental data and theoretically calculated dependencies, we have shown that the main contribution to the observed DC conductivity of this material results from the interfaces located at the borders of polycrystalline grains, although they possess a relatively low part of the total film volume. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structures of N1, N5‐dibenzoyltetrahydro‐4‐methyl‐1, 5‐benzodiazepin‐2‐one (DBTBO) and tetrahydro‐4‐methyl‐1, 5‐benzodiazepin‐2‐one (TBO)
Authors: Nallini A. , Saraboji K. , Ponnuswamy M. N. , Venkatraj M. , Jeyaraman R.
Published: April 2005

Adducing structural analogies between the two fused systems, N1, N5‐Dibenzoyltetrahydro‐4‐methyl‐1,5‐benzodiazepin‐2‐one, C24H20N2O3 (DBTBO CCDC 200341) and Tetrahydro‐4‐methyl‐1,5‐benzodiazepin‐2‐one, C10H12 N2O (TBO CCDC 200342) helps to find the pharmacological differences from the view point of variant hetero atom substitutions in the hetero cycle. Both the diazepines crystallized in identical monoclinic space group P21/n with a = 14.1134(1) Å, b = 9.2444(1) Å, c = 16.3812(1) Å; β = 107.11(1)º, V = 2042.7(3) Å3 for DBTBO and a = 9.3363(7) Å, b = 10.4895(8) Å, c = 9.9852(7) Å, β = 91.314(1)º, V = 977.62(1) Å3 for TBO, respectively. The two structures were solved by direct methods and refined by full‐matrix least‐squares procedure to final R‐values of R1 = 0.0575(DBTBO) and R1 = 0.0984(TBO). Structural differences include non‐identical boat conformations of these seven‐membered rings and the different non‐bonding interactions in the benzodiazepine pair.
Crystal structure and conformational analyses of a synthetic tetrapeptide t‐Boc‐L‐Val‐Aib‐Gly‐L‐Leu‐OMe
Authors: Singh Rathore Ravindranath
Published: April 2005

Crystal structure of a terminally blocked synthetic peptide, t‐Boc‐L‐Val‐Aib‐Gly‐L‐Leu‐OMe has been investigated. Two different conformers of peptide with one co‐crystallized water molecule, coexist in the crystal structure, in C2 space group. Both the conformers are stabilized by two intramolecular 1← 4 hydrogen bonds, between (Boc) C=O … HN (Gly) and (Val) C=O … HN (Leu), forming consecutive type II‐I' β‐turns. In the crystal, water interlinks peptide molecules, making a triangular bridge of pyramidal type. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Virtual datalink emulation and protocol development
Authors: Imaizumi Hideaki , Sugiura Kazunori , Murai Jun
Published: April 2005

In this paper, we propose and discuss a method for achieving expandability and portability through the protocol specifications and implementation of a virtual network. Technologies based on graph abstractions such as link‐state routing and broadcast techniques do not fundamentally depend on specific network technologies. Today, in order for these technologies to directly use the identifiers and communication protocols defined by a specific network technology, portability to other network technologies and adaptability to a heterogeneous network environment are degraded. The portability and adaptability to a heterogeneous network environment are improved by designing and implementing these technologies for a virtual network and emulating the virtual network on various networks. In this paper, to construct a virtual network, we explain a method for emulating the virtual datalink ANCIF proposing the same media access control protocol and protocol development using ANCIF. In practice, we applied and implemented ANCIF on various real networks, and measured the protocol overhead resulting from the virtual implementation. The result was extremely small overhead and almost no effect on performance. Finally, we discuss the portability to other network technologies and the adaptability to a heterogeneous network environment which are obtained by applying ANCIF. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(8): 32–40, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10204
Essential oil composition of Artemisia fragrans Willd. from Iran
Authors: Morteza‐Semnani Katayoun , Akbarzadeh Mohammad , Moshiri Kamran
Published: April 2005

The composition of the essential oil obtained from the dried ﬂowering aerial parts of Artemisia fragrans Willd. (Compositae) was analysed by GC and GC–MS for the ﬁrst time. Twenty‐seven components were identiﬁed in the essential oil of A. fragrans, whose major constituents were camphor (46.0%), 1,8‐cineole (23.7%) and camphene (7.9%). Copyright © 2004 John Wiley & Sons, Ltd.
Characterizing allelic associations from unphased diploid data by graphical modeling
Authors: Thomas Alun
Published: April 2005

A method for estimating a graphical model to describe allelic associations between genetic loci is extended to use diploid genotypes rather than haploid data. It also provides haplotype frequency estimates, estimates of phase for sampled individuals, allows for missing or partial information, genotyping errors, and arbitrary penetrance functions. A data set of 688 unrelated individuals genotyped on 25 genetic loci is used to illustrate haplotype frequency estimation. The frequencies obtained are shown to be similar to those obtained by the PHASE program. We also illustrate how putative loci for traits can be included in the analysis in order to detect allele‐phenotype associations. Haplotype reconstruction is illustrated on a standard set of 40 male X‐chromosome haplotypes, randomly paired to simulate diploid genotype data. The novel method is shown to be comparable to most existing ones, though the PHASE method does consistently better on this problem. The graphical model approach is shown to have some advantages in terms of tractability and can be used to select informative subsets of loci and to map loci influencing phenotypes.Genet. Epidemiol.© 2005 Wiley‐Liss, Inc.
System access hotspots: Are auditors ignoring danger?
Authors: Tyson Susan , Bean LuAnn
Published: April 2005

A recent survey found that only 54 percent of internal audit departments think information technology general controls are a critical part of complying with Sarbanes‐Oxley (SOX) Section 404. But management can't determine how effective its internal controls are without an in‐depth investigation of systems access security. Some internal auditors may be ignoring a lurking danger. So, the authors give detailed advice on how to secure hazardous system access hotspots. © 2005 Wiley Periodicals, Inc.
Ethics: Difficult questions, unpopular answers
Authors: Burton Eric James
Published: April 2005

Discussing and studying ethics is the “in” thing right now. There is a blizzard of reports, courses, news stories, and debates. But what's the bottom line? The author cuts through the confusion, saying there are several key questions we have to answer. This article examines the issues and shows what to do in a clear, thoughtful way. © 2005 Wiley Periodicals, Inc.
The risks of “paperless” bank checks
Authors: DeVries Delwyn D. , Kiger Jack E.
Published: April 2005

Are your auditors ready for the latest electronic revolution—Check 21? The Check Clearing for the 21st Century Act (Check 21) hastens the use of substitute bank checks. The substitutes consist of an electronic image of the front and back of checks presented for payment. And neither banks nor the disbursing party can require return of an original (paper) check. What risks do companies face from this “paperless” system? What new internal controls must firms establish? And since auditors won't be able to use paper checks as evidence of payment, what will they do? © 2005 Wiley Periodicals, Inc.
Sarbanes‐Oxley update: Where are we today?
Authors: Rouse Robert W. , Weirich Thomas R. , Hambleton Wendy M.
Published: April 2005

It has been over two years since Congress passed the Sarbanes‐Oxley Act (SOX) in an effort to restore investor confidence in the financial reporting of publicly held companies. So what has really changed? What is the situation today? The authors examine the aftermath of SOX and the latest guidance for companies struggling to comply. © 2005 Wiley Periodicals, Inc.
XRCC1 and DNA polymerase β interaction contributes to cellular alkylating‐agent resistance and single‐strand break repair
Authors: Wong Heng‐Kuan , Wilson David M.
Published: April 2005

X‐ray cross complementing 1 (XRCC1) protein has been suggested to bind to DNA single‐strand breaks (SSBs) and organize protein interactions that facilitate efficient DNA repair. Using four site‐specifically modified human XRCC1 mutant expression systems and functional complementation assays in Chinese hamster ovary (CHO) XRCC1‐deficient EM9 cells, we evaluated the cellular contributions of XRCC1s proposed N‐terminal domain (NTD) DNA binding and DNA polymerase β (POLβ) interaction activities. Results within demonstrate that the interaction with POLβ is biologically important for alkylating agent resistance and SSB repair, whereas the proposed DNA binding function is not critical to these phenotypes. Our data favor a model where the interaction of XRCC1 with POLβ contributes to efficient DNA repair in vivo, whereas its interactions with target DNA is biologically less relevant. Published 2005 Wiley‐Liss, Inc.
Proteomic analysis of differential protein expression in response to epidermal growth factor in neonatal porcine pancreatic cell monolayers
Authors: Hong Oak‐Kee , Suh Sun‐Hee , Kwon Hyuk‐Sang , Ko Seung‐Hyun , Choi Yoon‐Hee , Moon Sung‐Dae , Yoo Soon‐Jib , Son Ho‐Young , Park Kyung‐Soo , Lee In‐Kyu , Yoon Kun‐Ho
Published: April 2005

We have proposed that porcine neonatal pancreatic cell clusters (NPCCs) may be a useful alternative source of cells for islet transplantation, and that monolayer cultures might provide an opportunity to manipulate the cells before transplantation. In addition we previously identified 10 genes up‐regulated by epidermal growth factor (EGF) in cultured porcine NPCC monolayers. We have now analyzed the intracellular signaling pathways activated by EGF and searched for proteins differentially expressed following EGF treatment of the monolayers, using two‐dimensional gel electrophoresis (2‐DE) and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). EGF treatment resulted in phosphorylation of both Erk 1/2 and Akt, as well as increased cell proliferation. Five unknown and 13 previously identified proteins were differentially expressed in response to EGF. EGF treatment increased the expression of several structural proteins of epithelial cells, such as cytokeratin 19 and plakoglobin, whereas vimentin, the intermediate filament protein of mesenchymal cells, and non‐muscle myosin alkali chain isoform 1, decreased. Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 factor, which promotes epithelial cell proliferation, and hemoglobin alpha I & II also increased, whereas cyclin A1, immunoglobulin heavy chain, apolipoprotein A1, 5,10‐ethylenetetrahydrofolated reductase (5,10‐MTHFR), angiotensin‐converting enzyme 2 (ACE2), co‐lipase II precursor, and NAD+ isocitrate dehydrogenase (NAD+ IDH) alpha chain proteins decreased. Our results show that EGF stimulates proliferation of pancreatic epithelial cells by simultaneously activating the MAPK and PI‐3K pathways. HnRNP A2/B1, hemoglobin, cyclin A1, and ACE2 may play roles in the proliferation of epithelial cells in response to EGF. © 2005 Wiley‐Liss, Inc.
Syntheses of [14C] and [2H4]PD0205520, an inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor
Authors: Zhang Yinsheng , Huang Yun , Huang Che C.
Published: April 2005

5‐(4‐Methyl‐piperazin‐1‐yl)‐pent‐2‐ynoic acid [4‐(3‐chloro‐4‐fluoro‐phenylamino)‐pyrido[3,4‐d]pyrimidin‐6‐yl]‐amide, PD0205520, was under investigation as a potential inhibitor of the tyrosine kinase (TK) activity of the epidermal growth factor receptor (EGFR) for cancer treatment. Both radio‐ and stable‐isotope‐labeled compounds were required for drug absorption, distribution, metabolism and excretion (ADME) and quantitative mass spectrometry bio‐analytical studies. PD0205520 I4C‐labeled in the pyrimidine ring system was prepared in seven steps in an overall radiochemical yield of 26% from [14C]thiourea. PD0205520 2H‐Iabeled in the piperazine ring was synthesized in four steps in a 32% overall yield. Copyright © 2005 John Wiley & Sons, Ltd.
Batoid wing skeletal structure: Novel morphologies, mechanical implications, and phylogenetic patterns
Authors: Schaefer Justin T. , Summers Adam P.
Published: April 2005

The skeleton of the “wings” of skates and rays consists of a series of radially oriented cartilaginous fin rays emanating from a modified pectoral girdle. Each fin ray consists of small, laterally oriented skeletal elements, radials, traditionally represented as simple cylindrical building blocks. High‐resolution radiography reveals the pattern of calcification in batoid wing elements, and their organization within the fin ray, to be considerably more complex and phylogenetically variable than previously thought. Calcification patterns of radials varied between families, as well as within individual pectoral fins. Oscillatory swimmers show structural interconnections between fin rays in central areas of the wing. Morphological variation was strongly predictive of locomotor strategy, which we attribute to oscillatory swimmers needing different areas of the wing stiffened than do undulatory swimmers. Contributions of various forms of calcification to radial stiffness were calculated theoretically. Results indicate that radials completely covered by mineralized tissue (“crustal calcification”) were stiffer than those that were calcified in chain‐like patterns (“catenated calcification”). Mapping this functionally important variation onto a phylogeny reveals a more complicated pattern than the literature suggests for the evolution of locomotor mode. Therefore, further investigation into the phylogenetic distribution of swimming mode is warranted. J. Morphol. © 2005 Wiley‐Liss, Inc.
Miniaturized system of a gas chromatograph coupled with a Paul ion trap mass spectrometer B. J. Shortt, M. R. Darrach, Paul M. Holland and A. Chutjian Journal of Mass Spectrometry 2005; 40: 36–42
Authors: Shortt B. J. , Darrach M. R. , Holland Paul M. , Chutjian A.
Published: April 2005

The original article to which this Erratum refers was published in Journal of Mass Spectrometry 2005; 40: 36–42. Copyright © 2005 John Wiley & Sons, Ltd.
Low‐wavenumber dynamics of L‐alanine
Authors: Vik Aasmund F. , Yuzyuk Yuri I. , Barthes Mariette , Sauvajol Jean‐Louis
Published: April 2005

L‐Alanine is one of the simplest amino acids, the building block for many polypeptides and proteins. A previous Raman scattering study showed an anomalous temperature dependence of the intensity of the two lowest Raman modes, attributed to dynamic localization of vibrational energy. The present Raman data, collected in the b(cc)b scattering geometry, were aimed at understanding the dynamics of the low‐wavenumber modes in connection with the reported anomalies in other physical properties. Our study shows that the energy and intensity of the observed external modes show unusual behaviour in the temperature range ∼150–250 K. The anomalous temperature dependence of the peak of the NH3+ torsional mode is confirmed. Its wavenumber has a singularity around ∼220 K and its full width at half‐maximum does not increase linearly with temperature. The CH3 torsion and CO2− rock undergo similar discontinuities below ∼250 K. The intensity of the two lowest wavenumbers librons at 42 and 48 cm−1 shows an anomalous temperature dependence and vary in an opposite way from that reported for the c(bb)a scattering geometry. The nature of the subtle symmetry breaking occuring below ∼250 K is discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Initial hepatic microcirculation correlates with early graft function in human orthotopic liver transplantation
Authors: Puhl Gero , Schaser Klaus-D. , Pust Daniel , Köhler Katrin , Vollmar Brigitte , Menger Michael D. , Neuhaus Peter , Settmacher Utz
Published: April 2005

Microcirculatory disturbances are an initial causative determinant in hepatic ischemia/reperfusion injury. The aim of this study was to assess sinusoidal perfusion during human liver transplantation using orthogonal polarization spectral imaging and to evaluate the significance of intraoperative microcirculation for early postoperative graft function. Hepatic microcirculation was measured in 27 recipients undergoing full-size liver transplantation and compared to a group of 32 healthy living-related liver donors. The microvascular parameters were correlated with postoperative aspartate aminotransferase and bilirubin levels. Hepatic perfusion following liver transplantation was found to be significantly decreased when compared with the control group. Volumetric blood flow within the individual sinusoids increased due to sinusoidal dilatation and enhanced flow velocity. Regression analysis of postoperative aspartate aminotransferase and bilirubin with microvascular parameters revealed significant correlations. The extent of volumetric blood flow increased within the first 30 minutes after reperfusion and showed a significant correlation with postoperative aspartate aminotransferase release and bilirubin elimination. In conclusion, postischemic hepatic microvascular perfusion was analyzed in vivo, demonstrating significant microvascular impairment during liver transplantation. Sinusoidal hyperperfusion appears to confer protection against postischemic liver injury, as given by the correlation with aspartate aminotransferase and bilirubin levels. Thus, these findings may have therapeutic importance with respect to mechanisms mediating postischemic reactive hyperemia. (Liver Transpl 2005;11:555–563.)
A Novel Process for Ultrasound‐Induced Radical Polymerization in CO2‐Expanded Fluids
Authors: Kemmere Maartje F. , Kuijpers Martijn W. A. , Prickaerts Ramona M. H. , Keurentjes Jos T. F.
Published: April 2005

Summary: A strong viscosity increase upon polymerization hinders cavitation and subsequent radical formation during an ultrasound‐induced bulk polymerization. In this work, ultrasound‐induced radical polymerizations of methyl methacrylate (MMA) have been performed in CO2‐expanded MMA in order to reduce the viscosity of the reaction mixture. For this purpose, the phase behavior of CO2/MMA systems has been determined. With temperature oscillation calorimetry, the influence of CO2 on the viscosity and on the reaction kinetics of ultrasound‐induced polymerizations of MMA has been studied. In contrast to polymerizations in bulk, this technique shows that a low viscosity is maintained during polymerization reactions in CO2‐expanded MMA. As a consequence, a constant or even increasing polymerization rate is observed when pressurized CO2 is applied. Moreover, the ultrasound‐induced polymer scission in CO2‐expanded MMA is demonstrated, which appears to be a highly controlled process. Finally, a preliminary sustainable process design is presented for the production of 10 kg/h pure PMMA (specialty product) in CO2‐expanded MMA by ultrasound‐induced initiation.

Process flow diagram of the ultrasound‐induced polymerization of MMA in CO2‐expanded MMA.

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Process flow diagram of the ultrasound‐induced polymerization of MMA in CO2‐expanded MMA.
Modeling of the Emulsion Terpolymerization of Styrene, α‐Methylstyrene and Methyl Methacrylate
Authors: Hoppe Sandrine , Schrauwen Cornélius , Fonteix Christian , Pla Fernand
Published: April 2005

Summary: This work deals with modeling the terpolymerization of styrene, α‐methylstyrene and methyl methacrylate in the presence of an inhibitor. The model used is a “tendency model” based on the kinetics of the complex elementary chemical reactions both in the aqueous phase and in the particles. It considers the reversible propagation of α‐methylstyrene and the main physical phenomena occurring during the process, i.e., (i) partitioning of monomers, surfactant and inhibitor between the aqueous phase, polymer particles, monomer droplets and micelles; (ii) homogeneous and micellar nucleation; (iii) radical absorption and desorption; (iv) gel and glass effects. The main kinetic parameters of the model are estimated on the basis of batch experimental data in order to be able to describe the complete picture of this complex process. The model can be used to predict (with good precision) the global monomer conversion, number and weight‐average molecular weight, the average diameter and number of polymer particles and the glass transition temperature, and consequently to study the effects of AMS on conversion and terpolymer and latex characteristics.

Comparison of experimental and simulated results of the weight‐average molecular weight versus conversion for the emulsion terpolymerization of styrene, alpha methylstyrene and methyl methacrylate at 60 °C.

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Comparison of experimental and simulated results of the weight‐average molecular weight versus conversion for the emulsion terpolymerization of styrene, alpha methylstyrene and methyl methacrylate at 60 °C.
Comparison of Olefin Polymerization Processes with Metallocene Catalysts
Authors: Kaminsky Walter , Müller Fabian , Sperber Oliver
Published: April 2005

Summary: Solution and gas phase processes of the polymerization of ethene are compared using new types of pentalenyl bridged ansa‐metallocenes such as [Me3Pen(Flu)]ZrCl2. As of the bridge, the catalyst system is remarkable thermostable up to 105 °C and a deactivation of the metallocene on the silica support can be suppressed. Compared to the non‐supported catalyst in a solution process, the application of the heterogenized system in a gas phase process leads to a decrease in activities while molar masses of the polyethenes are similar. Due to a higher degree of short chain branches of 20–30 per 1 000 carbon atoms instead of 10–17, the melting temperatures are 10 °C lower than those for polymers obtained in the solution process.

Basic structure of the here used pentalenyl bridged ansa‐metallocenes.

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Basic structure of the here used pentalenyl bridged ansa‐metallocenes.
In‐Line Monitoring and Control of Conversion and Weight‐Average Molecular Weight of Polyurethanes in Solution Step‐Growth Polymerization Based on Near Infrared Spectroscopy and Torquemetry
Authors: Nogueira Evandro S. , Borges Cristiano P. , Pinto José C.
Published: April 2005

Summary: It is well known that the weight‐average molecular weight ($\overline M _{\rm w}$) is strictly dependent on conversion in step‐growth polymerizations performed in batch and that the $\overline M _{\rm w}$ is very sensitive to impurities and molar imbalance. This makes the work of controlling $\overline M _{\rm w}$ a non trivial job. In this paper a new methodology is introduced for in‐line monitoring and control of conversion and $\overline M _{\rm w}$ of polyurethanes produced in solution step‐growth polymerizations, based on near‐infrared spectroscopy (NIRS) and torquemetry. A calibration model based on the PLS method is obtained and validated for monomer conversion, while the weight‐average molecular weight is monitored indirectly with the relative shear signal provided by the agitator. Control procedures are then proposed and implemented experimentally to avoid gelation and allow for maximization of $\overline M _{\rm w}$. The proposed monitoring and control procedures can also be applied to other step growth polymerizations.

Proposed control scheme.

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Proposed control scheme.
Steady‐State Model for Olefin Polymerization With a Two‐Site Vanadium Catalyst in a Continuous Stirred‐Tank Reactor
Authors: D'Agnillo Luigi , Soares Joao B. P. , van Doremaele Gerard H. J.
Published: April 2005

Summary: In this study, a process for continuous EP(D)M production is examined and a mechanistic kinetic model is developed to explain the behavior exhibited by this vanadium‐catalyzed solution polymerization process. The catalyst system without promoter and without hydrogen, produces polymer with bimodal molecular weight distributions (MWDs), while the addition of catalyst promoter causes an order of magnitude increase in catalyst productivity and eliminates the higher‐MW component in the MWD. The addition of hydrogen also precludes bimodal MWDs, regardless of the presence of promoter. In all cases, the polymerization rate has a zero‐order rather than a first‐order response to monomer concentration. The zero‐order response of polymerization rate to monomer concentration is described using a mechanism of monomer coordination to form a stable complex prior to insertion. The bimodal MWDs at high monomer feeds (corresponding to low monomer conversion), in the absence of catalyst promoter and hydrogen, are explained by a two‐site type catalyst model in which both monomer insertion and the formation of the second‐site type occur after the monomer forms a stable coordinated complex with the first catalyst site type. The model reconciles the molecular weight development with these seldom‐discussed features of vanadium catalysis.

Propylene acting as a coordinating ligand at a coordinatively unsaturated vanadium catalyst site (adapted from ref.[7]).

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Propylene acting as a coordinating ligand at a coordinatively unsaturated vanadium catalyst site (adapted from ref.[7]).
Trunk sway in patients with spinocerebellar ataxia
Authors: Van de Warrenburg Bart P.C. , Bakker Maaike , Kremer Berry P.H. , Bloem Bastiaan R. , Allum John H.J.
Published: April 2005

We investigated whether quantified measurements of trunk sway during stance and gait tests in patients with autosomal dominant spinocerebellar ataxia (SCA) could be a useful approach to assess ataxia, which is highly relevant for adequate follow‐up and future intervention studies. Examined were 11 SCA patients and 11 age‐matched, healthy controls. Postural and balance control were quantified using peak‐to‐peak measurements of trunk angle and angular velocity, in the roll (lateral) and pitch (anterior–posterior) directions, during a battery of stance and gait tasks. In all stance tasks, trunk angle displacement and angular velocity in both the pitch and roll planes were significantly larger in the SCA group compared with the control group. Among the ataxia patients instability was more increased in the pitch than in the roll direction for two‐legged stance tasks, especially when standing on foam, with pronounced oscillations in the pitch plane at 1.4 and 2.5 Hz. A similar dominance of pitch over roll instability was also observed in most gait tasks, especially for tandem gait and while walking with simultaneous head rotations. Trunk sway measurements were effective in detecting and quantifying the gait and balance abnormalities in SCA patients, suggesting that this method might be used for follow‐up studies of SCA patients. Furthermore, the method might help to identify early symptomatic individuals and those patients at risk of falling. The postural instability in SCA was found to be multidirectional, although there is generally more pitch than roll instability corresponding with predominant involvement of the spinocerebellum. © 2005 Movement Disorder Society
Block‐row Hankel weighted low rank approximation
Authors: Schuermans M. , Lemmerling P. , Van Huffel S.
Published: April 2005

This paper extends the weighted low rank approximation (WLRA) approach to linearly structured matrices. In the case of Hankel matrices with a special block structure, an equivalent unconstrained optimization problem is derived and an algorithm for solving it is proposed. Copyright © 2005 John Wiley & Sons, Ltd.
On the convergence of the multi‐point flux approximation O‐method: Numerical experiments for discontinuous permeability
Authors: Eigestad G. T. , Klausen R. A.
Published: April 2005

This article presents numerical convergence results for the multi‐point flux approximation (MPFA) O‐method applied to the pressure equation in 2D. The discretization is made directly in physical space, and the investigated cases are simulated on structured, but generally skew grids. Skew grids need to be used to correctly represent the physics of the underlying flow problems. Special emphasis is made on cases which impose singularities in the velocity field. Such cases frequently arise in the description of subsurface flow. Analytical tools may not be applicable to fully answer the question of convergence for such cases; in particular not for the physical space discretization. © 2005 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Caribbean electricity restructuring: an assessment
Authors: Brewster Ancile
Published: April 2005

This article assesses the privatisation of the electricity sector in two Caribbean countries, Jamaica and Trinidad and Tobago, to determine if they have been successful and whether they have contributed benefits to the respective societies.

Two general methods are applied in assessing the success of the divestments; attainment of governments' stated objectives and commonly used utility performance metrics together with social and customer focus indicators. The results indicate that the stated objectives were broadly achieved, and the privatisation and its attempts brought benefits to the consumers and the society in general. The short to medium term benefits were accrued through lower labour costs per unit of electricity, higher performance of plant and operations and business led decision‐making. Long‐term benefits are accrued through the reduction or elimination of electricity supply deficits.

However, although the basic privatisations were successful, the absence of an adequate regulatory framework in one case may have reduced the quantum of benefits through failure to enforce continuous improvement in the privatised generation company, and reductions in worker rents in the public distribution company. Further, benefits were reduced by long divestment processes, accompanying strategic drift, opportunity costs from delayed sale proceeds and efficiency enhancement, and the costs to sustain interim operations. Copyright © 2005 John Wiley & Sons, Ltd.
Dysregulation of hedgehog signalling predisposes to synovial chondromatosis
Authors: Hopyan Sevan , Nadesan Puviindran , Yu Chunying , Wunder Jay , Alman Benjamin A
Published: April 2005

Synovial chondromatosis is a condition affecting joints in which metaplastic cartilage nodules arise from the synovium, causing pain, joint dysfunction, and ultimately joint destruction. Because dysregulation of hedgehog signalling is a feature of several benign cartilaginous tumours, expression of the hedgehog target genes PTC1 and GLI1 was examined in this study in samples from human synovial chondromatosis. Significantly higher expression levels were found in synovial chondromatosis than in the synovium, from which it arises. To determine if hedgehog‐mediated transcription predisposes to synovial chondromatosis, the extra‐toes mutant mouse, which harbours a heterozygous mutation in the hedgehog transcriptional repressor, Gli3, resulting in decreased expression of Gli3 protein, was studied. The extra‐toes mutant mouse has a phenotype consistent with overactive hedgehog signalling, suggesting that Gli3 acts as a transcriptional repressor of limb development. Eighty‐five per cent of Gli3 mutant mice developed synovial chondromatosis at 18 months of age, compared with 30% of wild‐type littermates (p < 0.05). Three of the ten Gli3 mutant mice treated with triparanol, which blocks hedgehog signalling upstream of the Gli transcription factors, developed synovial chondromatosis, compared with eight of ten control mice. These data demonstrate that hedgehog signalling plays an important role in the development of synovial chondromatosis and suggest that blockade of hedgehog signalling may be a potential treatment for this disorder. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Preparation of chiral polystyrene monoliths by utilizing W/O emulsion polymerization and their optical resolution ability
Authors: Teraguchi Masahiro , Ohtake Miyako , Inoue Hiroshi , Yoshida Akiko , Aoki Toshiki , Kaneko Takashi , Yamanaka Koji
Published: April 2005

We synthesized two kinds of chiral polystyrene‐based monoliths, which are macroporous gel with continuous open‐celled monolith structure. Thus, two chiral styrene monomers, (–)‐p‐[dimethyl(10‐pinanyl)silyl]styrene ((–)‐PSSt) and (–)‐p‐(menthoxycarbonyl)styrene ((–)‐MtSt]), were prepared and subjected to water‐in‐oil emulsion polymerization in the presence of divinylbenzene and AIBN. The macroporous structure of the obtained monoliths was directly confirmed by SEM observation. The obtained monoliths showed an optical resolution ability. That is, in the enantioselective adsorption using trans‐stilbene oxide, poly[(–)‐PSSt] monolith and poly[(–)‐MtSt] monoliths preferentially adsorbed (S,S)‐isomer [poly[(–)‐PSSt] monolith: α(S,S) = 1.49 (0.25 wt % acetone solution); poly[(–)‐MtSt] monolith: α(S,S) = 1.39 (0.25 wt % toluene solution)]. Depinanylsilylation of the poly[(−)‐PSSt] monolith and removal of menthyl groups from the poly[(–)‐MtSt] monolith were achieved by acid‐catalyzed scission of the SiC bond and base‐catalyzed hydrolysis, respectively. In addition, de‐poly[(–)‐PSSt] and de‐poly[(–)‐MtSt] showed enantioselectivity ((S,S)‐isomer preferentially absorbed) in adsorption using trans‐stilbene oxide in spite of the absence of chiral substituents in the monoliths. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2348–2357, 2005
Novel catalyst compositions for the syndiospecific polymerization of styrene prepared by the combination of cyclopentadenyl complexes of group IIA or group IIIA elements with titanium alkoxides
Authors: Tsai Jing‐Cherng , Kuo Jing Chung , Chen Yi‐Chun
Published: April 2005

A highly reactive catalyst system, which induces the syndiospecific polymerization of styrene with high activity, has been found by the combination of cyclopentadienyl (Cp) complexes of group IIA or group IIIA elements with titanium alkoxides. The 1H NMR monitoring of these reactions reveals the occurrence of a novel Cp‐transfer reaction that leads to the generation of Cp‐containing titanium complexes as catalysts for promoting the syndiospecific polymerization of styrene. Detailed in situ 1H NMR studies reveal that the rate of the Cp‐transfer reaction is highly dependent on the steric bulkiness of the titanium alkoxide complexes, the structures of the Cp complexes of group IIA or group IIIA elements, and the polymerization temperature. Styrene polymerization studies also reveal that a more effective Cp‐transfer reaction can typically lead to the generation of a more highly reactive catalyst for sPS polymerization. This study provides a convenient method for the in situ generation of variable structures of Cp/titanium alkoxide complexes, which are difficult to synthesize by other methods. Most importantly, the mixture of a catalyst precursor can be directly used as an sPS polymerization catalyst without isolation and purification of Cp/titanium complexes. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2304–2315, 2005