bluuebunny/crossref_metadata_2025 huggingface dataset:
RNA‐dependent nuclear matrix contains a 33 kb globin full domain transcript as well as prosomes but no 26S proteasomes
Authors: Ioudinkova Elena , Razin Sergey V. , Borunova Victoria , de Conto Flora , Rynditch Alla , Scherrer Klaus
Published: November 2004

Previously, we have shown that in murine myoblasts prosomes are constituents of the nuclear matrix; a major part of the latter was found to be RNase sensitive. Here, we further define the RNA‐dependent matrix in avian erythroblastosis virus (AEV) transformed erythroid cells in relation to its structure, presence of specific RNA, prosomes and/or proteasomes. These cells transcribe but do not express globin genes prior to induction. Electron micrographs show little difference in matrices treated with DNase alone or with both, DNase and RNase. In situ hybridization with alpha globin riboprobes shows that this matrix includes globin transcripts. Of particular interest is that, apparently, a nearly 35 kb long globin full domain transcript (FDT), including genes, intergenic regions and a large upstream domain is a part of the RNA‐dependent nuclear matrix. The 23K‐type of prosomes, previously shown to be co‐localized with globin transcripts in the nuclear RNA processing centers, were found all over the nuclear matrix. Other types of prosomes show different distributions in the intact cell but similar distribution patterns on the matrix. Globin transcripts and at least 80% of prosomes disappear from matrices upon RNase treatment. Interestingly, the 19S proteasome modulator complex is insensitive to RNase treatment. Only 20S prosomes but not 26S proteasomes are thus part of the RNA‐dependent nuclear matrix. We suggest that giant pre‐mRNA and FDTs in processing, aligning prosomes and other RNA‐binding proteins are involved in the organization of the dynamic nuclear matrix. It is proposed that the putative function of RNA within the nuclear matrix and, thus, the nuclear dynamic architecture, might explain the giant size and complex organization of primary transcripts and their introns. © 2004 Wiley‐Liss, Inc.
Characterization of events associated with apoptosis/anoikis induced by snake venom metalloproteinase BaP1 on human endothelial cells
Authors: Díaz Cecilia , Valverde Lorena , Brenes Oscar , Rucavado Alexandra , Gutiérrez José María
Published: November 2004

Human endothelial EA.hy926 cells were incubated with BaP1, a hemorrhagic metalloproteinase purified from Bothrops asper snake venom. Since the first hour of incubation with the proteinase, cells started showing DNA fragmentation, detected by a terminal deoxynucleotidyl transferase‐mediated dUDP nick‐end labeling (TUNEL)‐based photometric enzyme‐linked immunosorbent assay (ELISA). At later times, DNA fragments were predominantly located outside the cells, evidencing plasma membrane rupture. DNA fragmentation was completely abolished by Batimastat, a potent inhibitor of metalloproteinase enzymatic activity. Apoptosis induced by BaP1 on endothelial cells was independent of two Bcl‐2 family members (anti‐apototic Bcl‐xL and pro‐apoptotic Bax), that did not show any changes in their expression during a 24 h‐treatment period. Interestingly, IκBα, an inhibitor of NFκB, decreased after 24 h of treatment, suggesting further activation of the transcription factor. When some elements of the apoptotic extrinsic pathway were assessed, it was observed that procaspase‐8 completely disappeared after 24 h of treatment with BaP1, probably indicating its activation by a death receptor, whereas caspase‐8 inhibitor, cellular FLICE‐inhibitory protein (cFLIPL), increased its expression since the first hours of BaP1 incubation. In conclusion, treatment of human endothelial cells with BaP1 induces apoptosis/anoikis, independently of Bcl‐2 family members Bax and Bcl‐xL and associated with caspase‐8 activation and cFLIPL up‐regulation. Apoptosis was completely dependent on BaP1 enzymatic activity. Similarities between this and other endothelial cell anoikis‐related systems suggest that BaP1 and other snake venom metalloproteinases may be useful experimental tools in the study of death‐related events that occur when adherent cells loose contact with extracellular matrix. © 2004 Wiley‐Liss, Inc.
Retrospective study on poliomyelitis cases in northern Greece
Authors: Frantzidou Filanthi , Papa Anna , Chalkia Dimitra , Antoniadis Antonis
Published: November 2004

Here we report the results of a retrospective study on the epidemiological characteristics and genetic relationships of the virus isolates responsible for the last poliomyelitis cases in Greece. The last wild poliomyelitis case in Greece was detected in 1996, and the last vaccine‐related strain was isolated in 1998. The whole of Europe, including Greece, is now considered to be polio‐free. J. Clin. Lab. Anal. 18:296–298, 2004. © 2004 Wiley‐Liss, Inc.
Unmodified oligodeoxynucleotides require single‐strandedness to induce targeted repair of a chromosomal EGFP gene
Authors: Radecke Frank , Radecke Sarah , Schwarz Klaus
Published: November 2004

Background

A number of genetic defects in humans are due to point mutations in a single, often tightly regulated gene. Genetic treatment of such defects is preferably done by correcting only the altered base pair at the endogenous locus rather than by a gene replacement strategy involving viral vectors. Promisingly high repair rates have been achieved in some systems with the non‐viral approach of transfecting chimeric RNA/DNA oligonucleotides (chimeraplasts). However, since this technique does not yet perform robustly, several parameters thought to be important in oligonucleotide‐mediated gene repair were examined.

Methods

A series of transgenic HEK‐293 cell clones has been established harboring high or low copy numbers of a point‐mutated ‘enhanced green fluorescent protein’ (EGFP) gene as the target. At the level of single living cells, repair efficiencies were measured by fluorescence‐activated cell sorting (FACS) regarding topology (single‐stranded, double‐stranded), exonuclease protection (four phosphorothioate linkages at both ends), polarity (sense, antisense), and length (13mer, 19mer, 35mer, 69mer) of the oligonucleotide.

Results

When targeting chromosomal loci, up to 0.2% corrected cells were obtained with single‐stranded unmodified oligodeoxynucleotides, whereas a chimeraplast, its DNA analogue, and double‐stranded DNA fragments were practically non‐functional. Correction efficiencies correlated with target gene copy numbers. Modifying exonuclease resistance, polarity or length of single‐stranded oligodeoxynucleotides did not enhance repair efficacy above the sub‐percentage range.

Conclusions

Successful chromosomal reporter gene repair in HEK‐293 cells required an oligodeoxynucleotide to be single‐stranded. In concert with the gene copy number correlation, functional interaction between the repair molecule and the target site seems to be one bottleneck in targeted gene repair. Copyright © 2004 John Wiley & Sons, Ltd.
Synthesis of [quinoline‐3‐14C]‐SSR97193 (ferroquine) from [2‐14C]‐malonic acid
Authors: McNeill Alan , Murrell Victor , Taylor Keith
Published: November 2004

The antimalarial [quinoline‐3‐14C]‐SSR97193 (ferroquine) (8), an analogue of chloroquine (CQ) (1), was synthesized from [2‐14C]‐malonic acid with an overall radiochemical yield of 15%. The synthetic route via [14C]‐Meldrum's acid (9) was designed to minimize the intermediacy of radiolabelled volatiles. This synthesis involves a four‐step route to labelled 4,7‐dichloroquinoline, which is the key intermediate for the synthesis of many analogues of CQ. Copyright © 2004 John Wiley & Sons, Ltd.
On‐line size‐exclusion chromatography/mass spectrometry of low molecular mass heparin
Authors: Henriksen Jens , Ringborg Lene Hoffmeyer , Roepstorrf Peter
Published: November 2004

Heparin and low molecular mass heparin (LMMH) consists of complex mixtures of sulphated linear oligosaccharides that are difficult to analyse. An on‐line size exclusion chromatographic/electrospray ionization (ESI) mass spectrometric method that allows the determination of more than 60 components in an LMMH preparation is presented. The experimental setup includes on‐line cation exchange in order to prevent massive adducting in the ESI interface. Copyright © 2004 John Wiley & Sons, Ltd.
Epidemiological characteristics of human herpesvirus‐8 infection in a large population of antenatal women in Zambia
Authors: Klaskala W. , Brayfield B.P. , Kankasa C. , Bhat G. , West J.T. , Mitchell C.D. , Wood Charles
Published: November 2004

Comprehensive data describing epidemiological characteristics of the human herpesvirus‐8 or Kaposi's sarcoma‐associated herpesvirus (HHV‐8 or KSHV) infection among pregnant women in a central sub‐Saharan Africa are not available. This study determined virus prevalence estimates and the risk factors associated with HHV‐8 infection. Cross‐sectional, enrollment visit data were analyzed from a prospective cohort study of perinatal transmission of HHV‐8 in Lusaka, Zambia. Exposure data were obtained via structured interview, physical examination, medical chart review, and laboratory testing. Among 3,160 antenatal women serologically screened for HHV‐8 between September 1998 and October 2000, 40.2% were seropositive. The HHV‐8 positive women were more likely to be co‐infected with HIV‐1 than those who were HHV‐8 negative (34% vs. 26%; P < 0.0001). Of 154 variables evaluated by logistic regression analyses, only three risk factors, have emerged as independent predictors of HHV‐8 positive serology: diagnosis of genital warts, HIV‐1 co‐infection and primary education. The association of HHV‐8 infection with genital warts and HIV‐1 co‐infection suggests heterosexual transmission of HHV‐8. HIV‐1 infection may also act as a marker for particular behaviors, which could be sexual in nature, that are associated with both HIV‐1 and HHV‐8 transmission. Since HHV‐8 facilitates development of AIDS‐related Kaposi's sarcoma (KS), the results of this study could be utilized to identify specific population groups of pregnant women who are at increased risk for this disease. J. Med. Virol. 75:93–100, 2005. © 2005 Wiley‐Liss, Inc.
Heparan sulfate proteoglycans interact exclusively with conformationally intact HPV L1 assemblies: Basis for a virus‐like particle ELISA
Authors: Rommel Oliver , Dillner Joakim , Fligge Claudia , Bergsdorf Christian , Wang Xiaohong , Selinka Hans‐Christoph , Sapp Martin
Published: November 2004

In this article, we demonstrate that interaction of human papillomavirus‐like particles (HPV‐VLPs) with the putative glucosaminoglycan binding receptor is strictly dependent on conformational integrity. Such conformations are present on VLPs and capsomeres but not on monomers of the major capsid protein, L1, confirming reports that capsomeres can induce virus‐neutralizing antibodies. Furthermore, we show the suitability of this specific interaction for development of VLP‐based enzyme‐linked immunosorbent assays (ELISAs), using heparin for indirect coupling of VLPs to microtiter plates, which may add an intrinsic quality control. This avoids presentation of linear, often highly cross‐reactive epitopes of L1. In addition, heparin specifically interacts with a wide variety of HPV types, making it a prime candidate for a universal capture molecule. J. Med. Virol. 75:114–121, 2005. © 2005 Wiley‐Liss, Inc.
Protection against influenza virus infection by intranasal administration of hemagglutinin vaccine with chitin microparticles as an adjuvant
Authors: Hasegawa Hideki , Ichinohe Takeshi , Strong Peter , Watanabe Izumi , Ito Satoshi , Tamura Shin‐ichi , Takahashi Hidehiro , Sawa Hirofumi , Chiba Joe , Kurata Takeshi , Sata Tetsutaro
Published: November 2004

Chitin in the form of microparticles (chitin microparticles, CMP) has been demonstrated to be a potent stimulator of macrophages, promoting T‐helper‐1 (Th1) activation and cytokine response. In order to examine the mucosal adjuvant effect of CMP co‐administered with influenza hemagglutinin (HA) vaccine against influenza infection, CMP were intranasally co‐administered with influenza HA vaccine prepared from PR8 (H1N1) virus. Inoculation of the vaccine with CMP induced primary and secondary anti‐HA IgA responses in the nasal wash and anti‐HA IgG responses in the serum, which were significantly higher than those of nasal vaccination without CMP, and provided a complete protection against a homologous influenza virus challenge in the nasal infection influenza model. In addition, CMP‐based immunization using A/Yamagata (H1N1) and A/Guizhou (H3N2) induced PR8 HA‐reactive IgA in the nasal washes and specific‐IgG in the serum. The immunization with A/Yamagata and CMP resulted in complete protection against a PR8 (H1N1) challenge in A/Yamagata (H1N1)‐vaccinated mice, while that with A/Guizhou (H3N2) and CMP exhibited a 100‐fold reduction of nasal virus titer, demonstrating the cross‐protective effect of CMP and influenza vaccine. It is suggested that CMP provide a safe and effective adjuvant for nasal vaccination with inactivated influenza vaccine. J. Med. Virol. 75:130–136, 2005. © 2005 Wiley‐Liss, Inc.
Recurrent high level parvovirus B19/genotype 2 viremia in a renal transplant recipient analyzed by real‐time PCR for simultaneous detection of genotypes 1 to 3
Authors: Liefeldt Lutz , Plentz Annelie , Klempa Boris , Kershaw Olivia , Endres Anne‐Sophie , Raab Ulla , Neumayer Hans‐H. , Meisel Helga , Modrow Susanne
Published: November 2004

Organ transplant recipients infected with parvovirus B19 frequently develop persistent viremia associated with chronic anemia and pure red cell aplasia. In this study, a male renal transplant recipient who had been infected with parvovirus B19/genotype 2 after renal transplantation at the age of 34 years is described. The patient was repeatedly treated with high dose intravenous immunoglobulin (IVIG) that resulted in the resolvement of symptoms but not in virus eradication. During an observation period of 33 months after transplantation three phases associated with high parvovirus B19 viremia were observed. Both the first and the second viremic phases were combined with severe anemia. Parvovirus B19 specific IgM‐antibodies were initially detected at the beginning of the second phase in continually rising concentrations. Initially eradication of the virus by immunoglobulin therapy was reported after the first viremic phase [Liefeldt et al. (2002): Nephrol Dial Transplant 17:1840–1842]. Retrospectively this statement has to be corrected. It was based on the use of a qualitative PCR assay specific for parvovirus B19 genotype 1 associated with reduced sensitivity for detection of genotype 2. After sequence analysis of the viral DNA and adjustment of a real‐time PCR assay (TaqMan) for quantitative detection of all three B19 virus genotypes analysis of consecutive serum samples allowed the demonstration of long lasting phases with reduced viral loads following IVIG‐treatment. These results demonstrate that IVIG treatment of parvovirus B19‐triggered anemia in transplant recipients offers an opportunity to resolve symptoms, but does not guarantee eradication of the virus. Since reactivation of parvovirus B19 infection can result in high virus load associated with the recurrence of symptoms repeated screening for viral DNA is recommended using the TaqMan system established for quantitative detection of all three genotypes of parvovirus B19. J. Med. Virol. 75:161–169, 2005. © 2005 Wiley‐Liss, Inc.
Changing epidemiology of rotavirus G‐types circulating in Hong Kong, China
Authors: Chi Lo Janice Yee , Szeto Kai Cheung , Chong Tsang Dominic Ngai , Leung Kwok Hung , Ling Lim Wilina Wei
Published: November 2004

Group A rotaviruses are the most common cause of severe diarrhoeal disease in young children worldwide. The development of a vaccine is advocated by the World Health Organization. Obtaining local baseline information regarding rotavirus strain variation is important to ensure matching of circulating and vaccine strains. The current study was undertaken to determine the epidemiology of rotavirus G‐types in Hong Kong in anticipation of a vaccination program. From 2001 to 2002 over a period of one year, diarrhoeal stool specimens known to be positive for rotavirus were subjected to G‐typing by reverse transcriptase‐polymerase chain reaction using nested type‐specific primers. Rotavirus G‐type distribution was correlated with patient demographics. Among 747 rotavirus positive stool specimens, 723 strains could be G‐typed as G1 (302, 40.4%), G2 (128, 17.1%), G3 (231, 30.9%), G4 (24, 3.2%), and G9 (38, 5.1%). G1 strains were found predominantly in those 5 years old or younger (P < 0.0001), while G2 strains were more prevalent among those over 5 years of age (P < 0.001). When compared with similar studies in 1983 to 1984 and 1999 to 2000, there were significant changes in the prevalence of various G‐types, with consistent detection of G9 strains in the current study. It is concluded that rotavirus G‐type distribution in Hong Kong has varied with time. Continuous monitoring of the epidemiology of rotavirus is important, especially in anticipation of the introduction of a vaccine, in order to document its impact and to ensure its continued effectiveness. J. Med. Virol. 75:170–173, 2005. © 2005 Wiley‐Liss, Inc.
Coexpression of Brn‐3a POU protein with p53 in a population of neuronal progenitor cells is associated with differentiation and protection against apoptosis
Authors: Hudson Chantelle D. , Podesta Jennifer , Henderson Deborah , Latchman D.S. , Budhram‐Mahadeo V.
Published: November 2004

The Brn‐3a transcription factor is critical for survival and differentiation of sensory neurons derived from neural crest cells (NCC). Interaction of Brn‐3a with p53 results in differential effects on target gene expression, which profoundly affects fate of neuronal cells. Here we demonstrate colocalization of p53 in a subset of Brn‐3a‐positive NCC‐derived cells fated for the sensory neuronal lineage. The distinct morphology of Brn‐3a/p53‐coexpressing cells suggested a differentiated neuronal cell type, and this was confirmed by colocalization of p53 with differentiation marker NF‐160. Functional effects of Brn‐3a/p53 coexpression were analyzed in NCC cultured from Brn‐3a −/− embryos, which showed significantly increased apoptosis upon induction of p53 compared with wild‐type NCC, suggesting that Brn‐3a modulates the p53‐mediated fate of NCC that coexpress both factors. Thus, p53 is expressed in neuronal cells undergoing differentiation as well as apoptosis. Interaction with Brn‐3a in sensory neurons may be critical for modulating p53‐mediated gene expression and hence cell fate. © 2004 Wiley‐Liss, Inc.
Neurospheres: Insights into neural stem cell biology
Authors: Campos Lia Scotti
Published: November 2004

Neural stem cells (NSC) are a tissue‐specific subtype of self‐renewing and multipotent cells that can give rise to all neural populations. In this review, the importance of maintaining cell–cell contacts in the study of NSC is highlighted, and data obtained from some crucial single‐cell studies is compared to results obtained from neurospheres, where aggregates of NSC are grown in suspension. In particular, results that indicate how this culture system may be well suited to analyze NSC plasticity, cell–cell, and cell–extracellular matrix (ECM) interactions are pointed out, and the hypothesis that cell–cell and cell–ECM contacts may be essential for NSC maintenance, survival, and proliferation is highlighted. Finally, it is suggested that neurospheres might play a role in the study of context‐dependent behavior of NSC in niches by providing a system where NSC can be challenged chemically or biologically and analyzed in vitro, in a time‐ and context‐dependent manner. © 2004 Wiley‐Liss, Inc.
MHC Class I, β2 microglobulin, and the INF‐γ receptor are upregulated in aged motoneurons
Authors: Edström Erik , Kullberg Susanna , Ming Yu , Zheng Huaiyu , Ulfhake Brun
Published: November 2004

During aging, spinal cord motoneurons show characteristic changes including the loss of afferent boutons, a selective process that associates with gliosis and behavioral motor impairment. Evidence suggests that the major histocompatibility complex Class I (MHC I) system may be involved in synaptic plasticity of neurons during development and regeneration. In search of a mechanism governing senescent changes in synaptic connectivity, we report evidence for increased expression of MHC I and β2 microglobulin (β2M) in motoneurons and glial‐like profiles of 30‐month‐old rats. The regulatory signal(s) for MHC I expression in normal neurons remains unresolved but among tentative molecules are cytokines such as interferon‐γ (INF‐γ) and tumor necrosis factor α (TNF‐α). Interestingly, aged motoneurons, overlapping with those showing increased levels of MHC I, contained increased levels of INF‐γ receptor message. INF‐γ mRNA was detected at low levels in most (8/9) of the aged spinal cords but only infrequently (2/9) in young adult spinal cords; however, the cellular localization of INF‐γ mRNA could not be determined. Our data also indicates that TNF‐α is upregulated in the senescent spinal cord but that TNF‐α immunoreactive protein does not associate with motoneurons. We report evidence for an increased expression of MHC I and β2M in senescent spinal motoneurons and discuss the possibility that this regulation associates with INF‐γ or changes in neurotrophin signaling and neuron activity in senescence. © 2004 Wiley‐Liss, Inc.
Differential expression of Pax6 and Ngn2 between pair‐generated cortical neurons
Authors: Kawaguchi Ayano , Ogawa Masaharu , Saito Kanako , Matsuzaki Fumio , Okano Hideyuki , Miyata Takaki
Published: November 2004

Progenitor cells that generate neuron pairs (“pair progenitor cells”) are implicated in mammalian cortical development, and their division has been thought to be “symmetric.” However, asymmetric growth of two sister neurons generated by the division of a pair progenitor cell would lead to more efficient generation of neuronal diversity in the cortex. To explore mechanisms by which pair progenitor cells provide neuronal diversity, we examined molecular differences between a pair of neurons generated in clonal‐density culture. Time‐course analysis for the acquisition of neuronal markers and the disappearance of Pax6 and Neurogenin2 (Ngn2) demonstrated that 1) these transcription factors are expressed transiently in some but not all young neurons and 2) some neuron pairs showed uneven/asymmetric expression of Pax6 (19.5%) or Ngn2 (23.8%), whereas other pairs were either symmetrically positive or negative. Asymmetric Pax6 distribution in neuron pairs was not associated with asymmetric distribution of Numb, which raises an intriguing possibility, that Pax6 asymmetry in neuron pairs is produced by an alternative mode of the cell autonomous mechanisms. Stage‐dependent changes were noted in the pattern of Ngn2 retention in daughter neurons, reflecting qualitative changes in the pair progenitor population. We suggest that pair progenitor cells contribute to the generation of neuronal diversity through cell‐intrinsic heterogeneity and asymmetric division. © 2004 Wiley‐Liss, Inc.
On the relationships between circulation types and changes in rainfall variability in Greece
Authors: Maheras Panagiotis , Tolika Konstantia , Anagnostopoulou Christina , Vafiadis Margaritis , Patrikas Ioannis , Flocas Helena
Published: November 2004

An attempt is made to examine rainfall variability over the Greek area in relation to 500 hPa atmospheric circulation. Daily precipitation series from 22 evenly distributed Greek stations have been used for the period 1958–2000, along with the classification scheme of daily circulation types at 500 hPa for the same period. The seasonal frequency and the trends of circulation types have been calculated. It was found that there is a general positive trend of anticyclonic circulation types and a negative one for cyclonic types. The seasonal trends of rainy days and the precipitation totals have also been calculated and analysed. A general decreasing tendency of winter rainfall is observed; the decreasing trend during autumn and spring is less significant. Concerning the frequency and intensity of rainfall per circulation type, a decreasing tendency becomes evident for the majority of the stations during winter, whereas there is an increasing tendency during autumn. A multiple regression–cross‐validation model was developed using the seasonal frequency of circulation types as predictors and the seasonal rainfall totals as predictants. Only the winter modelled precipitation shows a good agreement with the observed precipitation, whereas for the other seasons the agreement is relatively poor. This could be caused by the influence of different factors that are not captured by the classification scheme used. The proposed model could serve as a circulation‐based downscaling method that could be further applied to geopotential data available from general circulation models in order to study regional climatological consequences of future climate scenarios. Copyright © 2004 Royal Meteorological Society
Oxidation limited life times of chromia forming ferritic steels
Authors: Huczkowski P. , Shemet V. , Piron‐Abellan J. , Singheiser L. , Quadakkers W. J. , Christiansen N.
Published: November 2004

Long term, cyclic oxidation studies of three high – Cr, ferritic steels were carried out at 800°C and 900°C in air. It was found that with decreasing sample thickness the life time of the mentioned alloys decreases due to breakaway phenomena. This effect is caused by faster exhaustion of the chromium reservoir from the bulk alloy in case of thinner components. The observed life time limits can be predicted with reasonable accuracy by a theoretical model, using oxide growth rate parameters, initial alloy Cr content and critical Cr content required for protective chromia scale formation. In the calculation it has, however, to be taken into account that the oxidation rates of the steels increase with decreasing specimen thickness.
Selective Guest Uptake from Solvent Mixtures in the Clathrate Phase of Syndiotactic Polystyrene
Authors: Uda Yukihiro , Kaneko Fumitoshi , Kawaguchi Tatsuya
Published: November 2004

Summary: Selective absorption uptake during the guest‐exchange processes in the δ form of syndiotactic polystyrene (sPS) was confirmed by IR spectroscopy. When films of the δ form were immersed in hexane/decane or chloroform/decane mixtures, decane molecules were incorporated preferentially in the δ form. Sorbate uptake by the δ form was greatly accelerated when the sorbate was mixed with a solvent penetrable to the amorphous region of sPS.

Concentration changes in a δ‐form film during sorption processes: sorption of a chloroform(D)/decane(H) mixture (1:1 molar ratio).

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Concentration changes in a δ‐form film during sorption processes: sorption of a chloroform(D)/decane(H) mixture (1:1 molar ratio).
Synthesis of Amphiphilic ABC Triblock Copolymers with PEO as the Middle Block
Authors: Mahajan Surbhi , Cho Byoung‐Ki , Allgaier Jürgen , Fetters Lewis J. , Coates Geoffrey W. , Wiesner Ulrich
Published: November 2004

Summary: Stepwise anionic polymerization, catalytic hydrogenation, and atom transfer radical polymerization were performed to synthesize an amphiphilic ABC triblock copolymer, poly(ethylene‐alt‐propylene)‐block‐poly(ethylene oxide)‐block‐poly(hexyl methacrylate) (PEP‐b‐PEO‐b‐PHMA), with hydrophilic PEO as the middle block. The resulting block copolymers have well‐defined molecular weights and narrow molecular weight distributions as revealed by 1H NMR spectroscopy and gel permeation chromatography.

GPC chromatograms of an ABC triblock copolymer, PEP‐b‐PEO‐b‐PHMA, and its intermediate precursors exhibiting narrow polydispersities.

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GPC chromatograms of an ABC triblock copolymer, PEP‐b‐PEO‐b‐PHMA, and its intermediate precursors exhibiting narrow polydispersities.
A Cyclodextrin Microgel for Controlled Release Driven by Inclusion Effects
Authors: Liu Yu‐Yang , Fan Xiao‐Dong , Kang Tao , Sun Le
Published: November 2004

Summary: A novel intelligent delivery system based on the environmental dependence of the inclusion effect of β‐cyclodextrin (β‐CD) with guest molecules, using a β‐CD polymer (CDP) microgel as carrier, is proposed. Compared with smart hydrogels, which are driven by the phase‐volume transition, controlled release from the CDP microgel is driven by “host‐guest” inclusion effects. With the pH‐dependent inclusion complexation of methyl orange (MO) with β‐CD as a model system, the behavior of the controlled release of a CDP microgel was tested by changing the pH, showing that the mechanism is reasonable.

Schematic illustration of the pH‐dependent inclusion complexation of MO with β‐CD in the CDP microgel.

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Schematic illustration of the pH‐dependent inclusion complexation of MO with β‐CD in the CDP microgel.
Cationic Polymerization: New Developments and Applications
Authors: Crivello J.V. , Kong S. , Jang M.
Published: November 2004

The chemistry and technology of photoinitiated cationic polymerization is a rapidly advancing field of investigation. This article reports on recent developments made in our laboratory in the development of new photoinitiators and photosensitizers. S,S‐Dialkyl‐S‐phenacylsulfonium salts have been prepared using a new, highly efficient and cost‐effective synthetic method and their use in the polymerization of various monomer systems studied. Also described is the development of alkoxyanthracene photosensitizers that may be employed to broaden the spectral sensitivity of various onium salt photoinitiators including the new S,S‐dialkyl‐S‐phenacylsulfonium salts. A marked acceleration of the rate of the ring‐opening polymerization of epoxide monomers was achieved using these photosensitizers. This article concludes with a brief discussion of the use of photoinitiated cationic polymerizations in such typical applications as can coatings, silicone release coatings and in stereolithography.
Nanotechnology for Smart Polymer Optical Devices
Authors: Rauter H. , Matyushin V. , Alguel Y. , Pittner F. , Schalkhammer T.
Published: November 2004

Within the last decade the use of nano‐structured polymers for biochips, biosensors and novel nano‐optical devices gained world‐wide attention due to a number of key‐developments. The most fascinating example is microelectronics, where smaller means more cost efficiency, more circuits per chip, faster, and less heat to dissipate. Many intriguing new phenomena occur at nanometer dimensions including quantum size effects, Coulomb blockade, plasmon wave guides and electron tunnelling.

Defined multilayer nano‐assemblies enable to construct three‐dimensional devices based on Plasmon and nano‐optic resonance. Decisive for these types of devices and sensors is the ultra‐precise nanometric assembly. Manufacturing of opto‐nano‐devices thus requires the development of a completely new set of ultra‐precise techniques to deposit, arrange, and couple nano‐polymer layers. These nano‐layers are the most essential key elements of novel nano‐optical‐devices. Smart‐responsive nano‐polymer gels as transducer and building blocks for nano‐devices open novel routes to photonic nano‐optical sensors and chips. Optical effects based on ‘resonance enhanced absorption (REA)’ in combination with nano‐layers of smart‐stimulus‐response polymers allow the construction of a new type of sensor device.

The article will focus on up‐to‐date lithographic techniques of nanolayers, continue to smart‐nanolayer polymers, describe the REA effect and lead to a functional REA‐polymer‐sensor.
Modification of Crosslinked Poly(styrene) Based Polymers for Boron‐Specific Extraction
Authors: Gazi Mustafa , Senkal Bahire Filiz , Bicak Niyazi
Published: November 2004

A new polymeric resin with glucose sulfonamide functions has been prepared for the extraction of boric acid. This poly (styryl sulfonamide) based resin has been demonstrated to be an efficient sorbent for the removal of boron. The resin had a boron loading capacity of 2.365 mmol.g−1 and showed reasonably rapid sorption ability. Splitting of sorbed boron can be achieved by simple acid leaching (2M H2SO4).
Semilinear wave equation with time dependent potential
Authors: Visciglia Nicola
Published: November 2004

We consider the following semilinear wave equation:
equation image
for (t,x) ∈ ℝt × ℝ. We prove that if the potential V(t,x) is a measurable function that satisfies the following decay assumption:
∣V(t,x)∣⩽C(1+t)(1+∣x∣) for a.e. (t,x) ∈ ℝt × ℝ
where C, σ0>0 are real constants, then for any real number λ that satisfies ${1+\sqrt{2}< \lambda <3}$ there exists a real number ρ(f,g,λ)>0 such that the equation has a global solution provided that 0<ρ⩽ρ(f,g,λ). Copyright © 2004 John Wiley & Sons, Ltd.
Floating table isotropic projection (FLIPR) acquisition: A time‐resolved 3D method for extended field‐of‐view MRI during continuous table motion
Authors: Fain Sean B. , Browning Fred J. , Polzin Jason A. , Du Jiang , Zhou Yong , Block Walter F. , Grist Thomas M. , Mistretta Charles A.
Published: November 2004

In this work, 3D vastly undersampled isotropic projection (VIPR) acquisition is used simultaneously with continuous table motion to extend the superior/inferior (S/I) FOV for MR angiograms. The new technique is termed floating table isotropic PR (FLIPR). The use of 3D PR in conjunction with table motion obviates the need to locate and prescribe imaging volumes containing the major blood vessels over the large superior–inferior (S/I) ranges encountered in whole‐body imaging. In addition, the FLIPR technique provides extended anterior–posterior (A/P) abdominal coverage, isotropic spatial resolution, and temporal resolution. In volunteer studies, FLIPR MR angiograms with 1.6‐mm isotropic spatial resolution that approached whole body in extent were acquired in less than 2 min. Magn Reson Med 52:1093–1102, 2004. © 2004 Wiley‐Liss, Inc.
Perfusion assessment with bolus differentiation: A technique applicable to hyperpolarized tracers
Authors: Johansson E. , Olsson L.E. , Månsson S. , Petersson J.S. , Golman K. , Ståhlberg F. , Wirestam R.
Published: November 2004

A new technique for assessing tissue blood flow using hyperpolarized tracers, based on the fact that the magnetization of a hyperpolarized substance can be destroyed permanently, is described. Assessments of blood flow with this technique are inherently insensitive to arterial delay and dispersion, and allow for quantification of the transit time and dispersion in the arteries that supply the investigated tissue. Renal cortical blood flow was studied in six rabbits using a 13C‐labeled compound (2‐hydroxyethylacrylate) that was polarized by the parahydrogen‐induced polarization (PHIP) technique. The renal cortical blood flow was estimated to be 5.7/5.4 ± 1.6/1.3 ml/min per milliliter of tissue (mean ± SD, right/left kidney), and the mean transit time and dispersion in the renal arteries were determined to be 1.47/1.42 ± 0.07/0.07 s and 1.78/1.93 ± 0.40/0.42 s2, respectively. Magn Reson Med 52:1043–1051, 2004. © 2004 Wiley‐Liss, Inc.
Quantification of the 31P metabolite concentration in human skeletal muscle from RARE image intensity
Authors: Greenman Robert L.
Published: November 2004

A method is described for quantifying the cellular phosphorus‐31 (31P) concentration in human skeletal muscle based on RARE (rapid acquisition with relaxation enhancement) image intensities. The 31P concentrations were calculated using relaxation rates, RF coil spatial characteristics, and RARE signal intensities from foot muscle and an external 31P standard. 31P RARE and 1H T2‐weighted images of the foot muscles in 11 normal subjects were acquired at 3.0 T using a double‐tuned (31P/1H) birdcage coil. 31P PRESS (point‐resolved spectroscopy) spectra were acquired to verify the measurable 31P concentrations in a multiecho acquisition. The mean measured concentration was 26.4 ± 3.1 mM (mean ± SD) from RARE signal intensities averaged over the entire imaged foot anatomy and 27.6 ± 4.1 mM for a 3 × 3 pixel region‐of‐interest measurement. The 31P RARE image acquisition time was 4 min with a 0.55 cm3 voxel size. These results demonstrate that the 31P concentration can be accurately measured noninvasively in human muscle from RARE images acquired in short scan times with relatively high spatial resolution. Magn Reson Med 52:1036–1042, 2004. © 2004 Wiley‐Liss, Inc.
Spatial correlations of laminar BOLD and CBV responses to rat whisker stimulation with neuronal activity localized by Fos expression
Authors: Lu Hanbing , Patel Sachin , Luo Feng , Li Shi‐Jiang , Hillard Cecilia J. , Ward B. Douglas , Hyde James S.
Published: November 2004

The spatial relationship between a measured fMRI signal and its underlying neuronal activity remains unclear. One obstacle is the localization of neuronal activity; another is the spatial resolution of fMRI. In the present study, high‐resolution BOLD and CBV fMRI experiments (voxel size: 156 × 156 × 2000 μm3) were conducted in the rat whisker barrel cortex at 3 T; neuronal activity across cortical layers was mapped using the Fos expression technique. Results show that BOLD response is weighted by blood volume and that pixels with high BOLD response can be located at the cortical surface or in deep layers, depending on local vasculature. In contrast to BOLD response, the pixels with high CBV response were consistently clustered in the deep cortical layers. Percentage‐CBV change in cortical layers IV–V was 7.3 ± 1.5%, which was significantly higher than in layers I–III (4.1 ± 0.9%) and VI (4.3 ± 0.7%) (mean ± SEM). The laminar distribution of CBV response correlates well with neuronal activity localized by Fos expression. We conclude that neuronal activity can be inferred from CBV fMRI data with high spatial accuracy. The data indicate that both intracolumn functional connectivity and neurovascular coupling can be studied using CBV fMRI. Magn Reson Med 52:1060–1068, 2004. © 2004 Wiley‐Liss, Inc.
System reliability based on diffusion models for fatigue crack growth
Authors: Ebrahimi Nader
Published: November 2004

Diffusion processes are commonly used to describe the dynamics of complex systems arising in a wide range of application fields. In this paper we propose, on the basis of diffusion processes, two models concerned with the stochastic behavior of fatigue cracks in a system. They are then used to get the distribution of the failure time, the first time the crack size of at least one of the cracks exceeds a given value. Several properties of our proposed models are presented, and the unknown parameters are estimated by the method of maximum likelihood. From these an estimate of failure time distribution is obtained. In this part, contrary to common practice, we do not assume availability of failure data. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2005
Relaxation induced by ferritin: a better understanding for an improved MRI iron quantification
Authors: Gossuin Yves , Muller Robert N. , Gillis Pierre
Published: November 2004

Ferritin, the iron storing protein, is known to darken T2‐weighted MRI. This darkening can be used to non‐invasively measure iron content. However, ferritin's behavior is not the same in tissue as in solution, a discrepancy that remains unexplained by the recently developed theory matching the NMR properties of ferritin solutions. A better understanding of the relaxation induced by ferritin in tissue could help for the development of new MRI protocols of iron quantification. In this short review, the main relaxation properties of ferritin in solution and in tissue are presented together with a discussion of the possible reasons for the faster transverse relaxation observed in tissues. Copyright © 2004 John Wiley & Sons, Ltd.
High‐resolution MR imaging of mouse brain microvasculature using the relaxation rate shift index Q
Authors: Wu Ed X. , Tang Haiying , Jensen Jens H.
Published: November 2004

Magnetic resonance imaging (MRI) is a powerful method for in vivo quantification of tissue properties. It has been previously proposed that the index Q ≡ δR2/(δR)2/3, where ΔR2 and δR are the spin echo and gradient echo relaxation rate shifts caused by the injection of an intravascular contrast agent, may be useful for characterizing microvasculature. In particular, Q is expected to correlate well with the density of microvessels. This study presents high‐resolution in vivo Q‐maps of normal mouse brain obtained with a superparamagnetic iron oxide contrast agent at a field of level of 9.4 T. Normative Q values are derived for several regions of interest and significant interregional variations are observed. Microvessel densities estimated from the Q‐maps are found to be in reasonable accord with histologically determined values. A possible application of Q‐maps is the assessment of angiogenic activity in tumors. Copyright © 2004 John Wiley & Sons, Ltd.
Iron oxide MR contrast agents for molecular and cellular imaging
Authors: Bulte Jeff W. M. , Kraitchman Dara L.
Published: November 2004

Molecular and cellular MR imaging is a rapidly growing field that aims to visualize targeted macromolecules or cells in living organisms. In order to provide a different signal intensity of the target, gadolinium‐based MR contrast agents can be employed although they suffer from an inherent high threshold of detectability. Superparamagnetic iron oxide (SPIO) particles can be detected at micromolar concentrations of iron, and offer sufficient sensitivity for T2(*)‐weighted imaging. Over the past two decades, biocompatible particles have been linked to specific ligands for molecular imaging. However, due to their relatively large size and clearance by the reticuloendothelial system (RES), widespread biomedical molecular applications have yet to be implemented and few studies have been reproduced between different laboratories. SPIO‐based cellular imaging, on the other hand, has now become an established technique to label and detect the cells of interest. Imaging of macrophage activity was the initial and still is the most significant application, in particular for tumor staging of the liver and lymph nodes, with several products either approved or in clinical trials. The ability to now also label non‐phagocytic cells in culture using derivatized particles, followed by transplantation or transfusion in living organisms, has led to an active research interest to monitor the cellular biodistribution in vivo including cell migration and trafficking. While most of these studies to date have been mere of the ‘proof‐of‐principle’ type, further exploitation of this technique will be aimed at obtaining a deeper insight into the dynamics of in vivo cell biology, including lymphocyte trafficking, and at monitoring therapies that are based on the use of stem cells and progenitors. Copyright © 2004 John Wiley & Sons, Ltd.
Adaptivity for finite volume on unstructured triangular meshes: a study of thermal injury in teeth
Authors: Martins Marcio Arêdes , Oliveira Leandro Soares , Valle Ramón Molina
Published: November 2004

This paper presents a numerical study of thermal injury in teeth, caused both by convective heating, due to drinking of hot beverage and mastication of foods, and by laser irradiation in dental treatment. The numerical study employs an adaptive finite volume method on unstructured triangular meshes to solve the governing equations. An adaptive time stepping methodology was also used in order to control the solution error. Adaptive methodologies are adequate to solve such problems since steep gradients will develop at specific locations in the domain of study. The convective heating results were compared to experimental data available in the literature. Laser treatment results are in agreement to the temperature increasing observed in literature. The simulation results demonstrate that both the error estimate and adaptive methodology herein proposed are suitable and reliable for the controlled solution of parabolic problems. Copyright © 2004 John Wiley & Sons, Ltd.
Investigation for aneuploidy of chromosomes 7, 9, 10, 17 and p53 gene deletions between low and high grade glial tumors using interphase FISH technique
Authors: Yakut Tahsin , Bekar Ahmet , Egeli Unal , Doygun Muammer , Ercan İlker , Yigit Barboros , Ogul Erhan
Published: November 2004

We investigated for aneuploidy of chromosomes 7, 9, 10, 17, and p‐53 gene deletions in 36 glial tumor tissues, using interphase fluorescence in sity hybridization (FISH), and compared the frequencies of abnormalities between low and high grade tumors. Among the 13 low grade tumors; 1 had trisomy 7, 1 had monosomy 9, 2 had monosomy 10, 1 had monosomy 17, 1 had p53 deletion, and among the 23 high grade tumors; 10 had trisomy 7, 1 had monosomy 9, 7 had monosomy 10, 2 had monosomy 17, 6 had p 53 deletion. The results indicated that neither aneuploidy of chromosome 9, nor chromosome 17 are prominent findings between low or high grade of glial tumors, although high‐grade glial tumors have higher rates of trisomy 7 (43.5%), monosomy 10 (30.4%) and p53 (26%) deletion than low‐grade ones. Statistical results showed significant difference between trisomy 7 and high grade astorocytomas (p=0.031). Considering these chromosomal abnormalities we suggest that trisomy 7, loss of chromosome 10 and alterations of the p53 gene have important role associated with glial tumor development and trisomy 7 is the most important genetic changes associated with glial tumor progression.
Influence of prenatal noise and music on the 5‐hydroxytryptamine synthesis and the tryptophan hydroxylase expression in the raphe nuclei of young rats
Authors: Kim Eun‐Kyung , Kim Hong , Lee Myoung‐Hwa , Kim Young‐Sick , Yang Hye‐Young , Chang Hyun‐Kyung , Lee Taeck‐Hyun , Jang Mi‐Hyeon , Shin Min‐Chul , Lee Sam‐Jun , Lee Hee‐Hyuk , Shin Mal‐Soon , Kim Chang‐Ju
Published: November 2004

During the prenatal period, development of individual is influenced by the environmental factors. In mammals, 5‐hydroxytryptamine (5‐HT) is a central neurotransmitter that regulates behavioral functions in the vertebrate brain. Tryptophan hydroxylase (TPH) is a rate‐limiting enzyme in the 5‐HT synthesis. Various stresses are known to modulate the 5‐HT synthesis and the TPH expression. In the present study, the influence of prenatal noise and music aplication on the 5‐HT synthesis and the TPH expression in the dorsal and median raphe of young rats was investigated. Prenatal noise application increased the 5‐HT synthesis and the TPH expression in the dorsal and median raphe nuclei of offspring. Prenatal music application, in contrast, decreased the 5‐HT synthesis and the TPH expression in the dorsal and median raphe nuclei of offspring. The present study suggests that prenatal stimuli including noise and music may affect the emotional state of offspring.