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Terms modified by Nb Selected AbstractsChemInform Abstract: Preparation and Characterization of a Tetranuclear and Mixed-Valence Nb(II)/Nb(III) Diamagnetic Nb4Cl12Li2(THF)8 Cluster.CHEMINFORM, Issue 30 2001Maryam Tayebani Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] End-Anchored Polymers: Compression by Different Mechanisms and Interpenetration of Apposing LayersMACROMOLECULAR THEORY AND SIMULATIONS, Issue 2 2005Mark D. Whitmore Abstract Summary: This paper presents a systematic study of the compression of end-anchored polymer layers by a variety of mechanisms. We treat layers in both good and , solvents, and in the range of polymer densities that is normally encountered in experiments. Our primary technique is numerical self-consistent field (NSCF) theory. We compare the NSCF results for the different mechanisms with each other, and with those of the analytic SCF theory. For each mechanism, we calculate the density profiles, layer thicknesses, and free energies, all as functions of the degree of polymerization and surface coverage. The free energy and the deformation of each layer depend on the compression mechanism, and they can be very different from the ASCF theory. For example, the energy of compression can be as much as three times greater than the analytical SCF (ASCF) prediction, and it does not reduce to simple, universal functions of the reduced distance between the surfaces. The overall physical picture simplifies if the free energy is expressed in terms of the layer deformation, rather than the reduced surface separation. We also examine and quantify the interpenetration of layers, discuss why ASCF theory applies better to some compression mechanisms than others, and end with comments on the difficulties in extracting quantitative information from surface-forces experiments. Comparisons of forces of compression in a good solvent for the three different systems, as functions of D/nb. The lower three curves are for ,*,=,3, and the upper three are for ,*,=,23. [source] The complex phosphate K0.92In0.46Nb0.54OPO4: a new representative of the KTiOPO4 familyACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2007Artem A. Babaryk Aliovalent K0.92In0.46Nb0.54OPO4 (KINP, potassium indium niobium oxide phosphate) features a chain structure involving corner-sharing [MO6] octahedra (M = In/Nb), which allows this compound to be recognized as a member of the KTiOPO4 (KTP) family. However, its crystallization in the polar space group P41 belonging to the 4/m Laue group generates its own subclass of KTP-related compounds. The unit cell contains 18 symmetry-independent atoms occupying general positions. The cis,cis principle of octahedral arrangement is observed for each of the separate [MO6], chains. The observed variations in the cis,cis linkage are critically important for nonlinear optical properties and distinguish the present compound from other KTP-related structures. The anionic framework adopts one-dimensional tunnels running orthogonal to the ab plane. The K+ ions are arranged in the [001] direction at a distance of c. Merohedral twinning was detected during the structure refinement. [source] Separation of Nile Blue-labelled fatty acids by CE with absorbance detection using a red light-emitting diodeELECTROPHORESIS, Issue 8 2007Michael C. Breadmore Dr. Abstract The separation of fatty acids derivatised with Nile Blue (NB) by CE with detection using a red light-emitting diode (LED) was examined. NB was selected as the derivatisation agent due to its high molar absorption coefficient of 76,000,M,1cm,1 at 633,nm, making it well suited for sensitive absorbance detection using a red 635,nm LED. NB-labelled fatty acids were separated by both MEKC using SDS micelles, i -PrOH and n -BuOH and by NACE in a number of solvents including MeOH, EtOH and ACN. The sensitivity of NACE was superior to MEKC, with detection limits of 5×10,7,7×10,7,M obtained for each acid, approximately 20 times lower than the MEKC method. The NACE detection limits are approximately 100 times lower than previous reports on the separation of fatty acids by CE using indirect absorbance detection, ten times lower than using indirect fluorescence detection and are inferior only to those obtained using precapillary derivatisation and direct fluorescence detection. The efficiency of the NACE method was also superior to MEKC and allowed the separation of unsaturated fatty acids to be examined, although it was not possible to baseline-resolve linoleic (C18:2) and linolenic (C18:3) acids in a reasonable time. The method was used to analyse the fatty acid profile of two edible oils, namely sunflower and sesame oils, after alkali hydrolysis, where it was possible to identify both the saturated and unsaturated fatty acids in each sample. [source] Gene expression in caged fish as a first-tier indicator of contaminant exposure in streamsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2005Aaron P. Roberts Abstract The development of sensitive, biologically based indicators of contaminant exposure (i.e., biomarkers) is an ongoing topic of research. These indicators have been proposed as a first-tier method of identifying contaminant exposure. The primary objective of this research was to implement a biomarker-based method of exposure assessment using caged fish and real-time reverse-transcriptase polymerase chain reaction (rtRT-PCR) measurements of gene expression. Primers were developed for the CYPIA, metallothionein, and vitellogenin genes in rainbow trout (Oncorhynchyus mykiss), cutbow trout (Oncorhynchyus clarkii × mykiss), and Atlantic salmon (Salmo salar). Each of these genes has been shown to respond specifically to planar aromatic compounds, heavy metals, and environmental estrogens, respectively. Juvenile fish were placed in cages and exposed in situ at reference and contaminated sites on the Cache la Poudre River (CO, USA), the Arkansas River (CO, USA), the St. John River (NB, Canada), and two urban creeks near Dayton (OH, USA). Quantitative gene expression was determined using rtRT-PCR. Biomarker expression profiles were obtained that demonstrated differences in CYP1A, metallothionein, and vitellogenin mRNA production unique to each site, indicating that specific types of compounds were bioavailable and present in sufficient concentrations to elicit transcriptional responses in the organism. These findings support the use of a biomarker-based approach to exposure identification and assessment. [source] Neurobrucellosis as an exceptional cause of transient ischemic attacksEUROPEAN JOURNAL OF NEUROLOGY, Issue 5 2006A. Bingöl We report a series of four cases presented with transient ischemic attacks (TIA) or ischemic stroke as the predominant manifestation of neurobrucellosis (NB). Three of the patients were 20,28 years of age, and one patient was 53 years old. They all used to consume unpasteurized milk or its products. Two patients had systemic brucellosis in the past and received antibiotic treatment. Other causes of TIA including cardiac embolism, hypercoagulability, vascular malformations, systemic vasculitis, and infective endocarditis were excluded. NB was diagnosed with serological tests or cultures for Brucella in the cerebrospinal fluid. None of the patients had any further TIA after the initiation of specific treatment. NB should always be sought in young patients with TIA or ischemic stroke, especially if they have no risk factors for stroke and live in an endemic area for brucellosis, even if they do not have other systemic signs of brucellosis. [source] CAC and routing for multi-service networks with blocked wide-band calls delayed, part I: exact link MDP frameworkEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 1 2006Ernst Nordström In this paper, we study the call admission control (CAC) and routing issue in multi-service networks. Two categories of calls are considered: a narrow-band (NB) with blocked calls cleared and a wide-band (WB) with blocked calls delayed. The objective function is formulated as reward maximisation with penalty for delay. The optimisation is subject to quality of service (QoS) constraints and, possibly, grade of service (GoS) constraints. A suboptimal solution is achieved by applying Markov decision process (MDP) theory together with a two-level approximation. First, the network is decomposed into a set of links assumed to have independent Markov and reward processes respectively. Second, the dimensions of the link Markov and reward processes are reduced by aggregation of the call classes into call categories. The CAC and routing policy is computed by the policy iteration algorithm from MDP theory. The numerical results show that the proposed CAC and routing method, based on the exact link MDP framework, is able to find an efficient trade-off between reward loss and average call set-up delay, outperforming conventional methods such as the least loaded routing (LLR). Copyright © 2005 AEIT. [source] Small heat shock protein Hsp27 prevents heat-induced aggregation of F-actin by forming soluble complexes with denatured actinFEBS JOURNAL, Issue 22 2007Anastasia V. Pivovarova Previously, we have shown that the small heat shock protein with apparent molecular mass 27 kDa (Hsp27) does not affect the thermal unfolding of F-actin, but effectively prevents aggregation of thermally denatured F-actin [Pivovarova AV, Mikhailova VV, Chernik IS, Chebotareva NA, Levitsky DI & Gusev NB (2005) Biochem Biophys Res Commun331, 1548,1553], and supposed that Hsp27 prevents heat-induced aggregation of F-actin by forming soluble complexes with denatured actin. In the present work, we applied dynamic light scattering, analytical ultracentrifugation and size exclusion chromatography to examine the properties of complexes formed by denatured actin with a recombinant human Hsp27 mutant (Hsp27,3D) mimicking the naturally occurring phosphorylation of this protein at Ser15, Ser78, and Ser82. Our results show that formation of these complexes occurs upon heating and accompanies the F-actin thermal denaturation. All the methods show that the size of actin,Hsp27-3D complexes decreases with increasing Hsp27-3D concentration in the incubation mixture and that saturation occurs at approximately equimolar concentrations of Hsp27-3D and actin. Under these conditions, the complexes exhibit a hydrodynamic radius of ,,16 nm, a sedimentation coefficient of 17,20 S, and a molecular mass of about 2 MDa. It is supposed that Hsp27-3D binds to denatured actin monomers or short oligomers dissociated from actin filaments upon heating and protects them from aggregation by forming relatively small and highly soluble complexes. This mechanism might explain how small heat shock proteins prevent aggregation of denatured actin and by this means protect the cytoskeleton and the whole cell from damage caused by accumulation of large insoluble aggregates under heat shock conditions. [source] Reduced levels of miR-34a in neuroblastoma are not caused by mutations in the TP53 binding site,GENES, CHROMOSOMES AND CANCER, Issue 7 2009Galina Feinberg-Gorenshtein Neuroblastoma (NB) is the most common extracranial solid tumor in children below the age of 5 years. miR-34a, located in chromosome band 1p36, has been recently implicated as a tumor suppressor gene in NB. In addition, it has been shown that miR-34a is activated by TP53 by binding to a TP53 binding site upstream to the mature miR-34a. We studied NB tumors from 57 patients for miR-34a expression levels, 1p status, mutations in the TP53 coding region and mutations of the TP53 binding site. Reduced expression levels of miR-34a were identified in tumors harboring 1p36.3 Loss (P = 0.028). No mutations were identified in the coding region of TP53, or in the TP53 binding site. Thus, mutations in the binding site are not an additional mechanism for the inactivation of miR-34a in NB. Other regulatory mechanisms controlling miR-34a expression and its relationship to TP53 should be further explored. © 2009 Wiley-Liss, Inc. [source] Erythropoietin/erythropoietin receptor system is involved in angiogenesis in human neuroblastomaHISTOPATHOLOGY, Issue 5 2007D Ribatti Aims:, Previous studies have shown that increased vascularity is associated with tumour progression in human neuroblastoma (NB). The involvement of erythropoietin (Epo) in tumour angiogenesis has also been reported. The aim of this study was to correlate microvascular density and Epo/Epo-receptor (EpoR) expression in endothelial and tumour cells to the clinical stage of NB. Methods and results:, Specimens of NB obtained from 20 patients were investigated immunohistochemically by using anti-CD31, anti-Epo and anti-EpoR antibodies. The extent of angiogenesis was found to be up-regulated in advanced disease. In keeping with this observation, Epo/EpoR expression in tumour and endothelial cells, respectively, was also highly correlated with the extent of angiogenesis and higher clinical stage. Conclusions:, The correlation of Epo/EpoR expression with angiogenesis and tumour progression suggests the presence of a loop in the Epo,EpoR system. Epo is secreted by tumour cells and affects vascular endothelial cells via its receptor, promoting tumour angiogenesis in a paracrine manner. Data suggest that Epo represents an important mediator in NB angiogenesis. Understanding the mechanisms of NB angiogenesis provides the basis for a rational approach to the development of antiangiogenic therapy in patients affected by NB. [source] Using GIS and a digital elevation model to assess the effectiveness of variable grade flow diversion terraces in reducing soil erosion in northwestern New Brunswick, CanadaHYDROLOGICAL PROCESSES, Issue 23 2009Qi Yang Abstract Flow diversion terraces (FDT) are commonly used beneficial management practice (BMP) for soil conservation on sloped terrain susceptible to water erosion. A simple GIS-based soil erosion model was designed to assess the effectiveness of the FDT system under different climatic, topographic, and soil conditions at a sub-basin level. The model was used to estimate the soil conservation support practice factor (P -factor), which inherently considered two major outcomes with its implementation, namely (1) reduced slope length, and (2) sediment deposition in terraced channels. A benchmark site, the agriculture-dominated watershed in northwestern New Brunswick (NB), was selected to test the performance of the model and estimated P -factors. The estimated P -factors ranged from 0·38,1·0 for soil conservation planning objectives and ranged from 0·001 to 0·45 in sediment yield calculations for water-quality assessment. The model estimated that the average annual sediment yield was 773 kg ha,1 yr ,1 compared with a measured value of 641 kg ha,1 yr,1. The P -factors estimated in this study were comparable with predicted values obtained with the revised universal soil loss equation (RUSLE2). The P -factors from this study have the potential to be directly used as input in hydrological models, such as the soil and water assessment tool (SWAT), or in soil conservation planning where only conventional digital elevation models (DEMs) are available. Copyright © 2009 John Wiley & Sons, Ltd. [source] Differential mRNA expression levels and gene sequences of carboxylesterase in both deltamethrin resistant and susceptible strains of the cotton aphid, Aphis gossypiiINSECT SCIENCE, Issue 3 2008Chuan-Wang Cao Abstract Extensive use of insecticides on cotton has prompted resistance development in the cotton aphid, Aphis gossypii (Glover) in China. A deltamethrin-selected population of cotton aphids from Xinjiang Uygur Autonomous Region, China with 228.59-fold higher resistance to deltamethrin was used to examine how carboxylesterase conferred resistance to this pyrethroid insecticide. The carboxylesterase activity in the deltamethrin-resistant strain was 3.67-, 2.02- and 1.16-fold of the susceptible strain when using ,-naphthyl acetate (,-NA), ,-naphthyl acetate (,-NA) and ,-naphthyl butyrate (,-NB) as substrates, respectively. Carboxylesterase cDNA was cloned and sequenced from both deltamethrin-resistant and susceptible strains. The cDNA contained 1581 bp open reading frames (ORFs) coding a 526 amino acid protein. Only one amino acid substitution (Val87 -Ala) was observed between deltamethrin-resistant and susceptible strains but it is not genetically linked to resistance by the catalytic triad and signature motif analysis. The real-time polymerase chain reaction analysis indicated that the resistant strain had a 6.61-fold higher level of carboxylesterase mRNA than the susceptible strain. The results revealed that up-regulation of the carboxylesterase gene, not modified gene structure, may be responsible for the development of resistance in cotton aphids to deltamethrin. [source] Pml and TAp73 interacting at nuclear body mediate imatinib-induced p53-independent apoptosis of chronic myeloid leukemia cellsINTERNATIONAL JOURNAL OF CANCER, Issue 1 2009Jin-Hwang Liu Abstract Bcr-abl signals for leukemogenesis of chronic myeloid leukemia (CML) and activates ras. Since the function of promyelocytic leukemia protein (pml) is provoked by ras to promote apoptosis and senescence in untransformed cells, the function is probably masked in CML. Imatinib specifically inhibits bcr-abl and induces apoptosis of CML cells. As reported previously, p53wild CML was more resistant to imatinib than that lacking p53. Here, we searched for an imatinib-induced p53 independent proapoptotic mechanism. We found imatinib up-regulated phosphorylation of p38 mitogen-activated protein kinase (MAPK), checkpoint kinase 2 (chk2) and transactivation-competent (TA) p73; expression of pml and bax; formation of PML-nuclear body (NB); and co-localization of TAp73/PML-NB in p53-nonfunctioning K562 and p53mutant Meg-01 CML cells, but not in BCR-ABL - HL60 cells. In K562 cells, with short interfering RNAs (siRNAs), knockdown of pml led to dephosphorylation of TAp73. Knockdown of either pml or TAp73 abolished the imatinib-induced apoptosis. Inhibition of p38 MAPK with SB203580 led to dephosphorylation of TAp73, abolishment of TAp73/PML-NB co-localization, and the subsequent apoptosis. Conversely, interferon ,-2a (IFN,), which increased phosphrylated TAp73 and TAp73/PML-NB co-localization, increased additively apoptosis with imatinib. The imatinib-induced TAp73/PML-NB co-localization was accompanied by co-immpunoprecipitation of TAp73 with pml. The imatinib-induced co-localization was also found in primary CML cells from 3 of 6 patients, including 2 with p53mutant and one with p53wild. A novel p53-independent proapoptotic mechanism using p38 MAPK /pml/TAp73 axis with a step processing at PML-NB and probably with chk2 and bax being involved is hereby evident in some imatinib-treated CML cells. © 2009 UICC [source] Identification of 2 putative critical segments of 17q gain in neuroblastoma through integrative genomicsINTERNATIONAL JOURNAL OF CANCER, Issue 5 2008Jo Vandesompele Abstract Partial gain of chromosome arm 17q is the most frequent genetic change in neuroblastoma (NB) and constitutes the strongest independent genetic factor for adverse prognosis. It is assumed that 1 or more genes on 17q contribute to NB pathogenesis by a gene dosage effect. In the present study, we applied chromosome 17 tiling path BAC arrays on a panel of 69 primary tumors and 28 NB cell lines in order to reduce the current smallest region of gain and facilitate identification of candidate dosage sensitive genes. In all tumors and cell lines with 17q gain, large distal segments were consistently present in extra copies and no interstitial gains were observed. In addition to these large regions of distal gain with breakpoints proximal to coordinate 44.3 Mb (17q21.32), smaller regions of gain (distal to coordinate 60 Mb at 17q24.1) were found superimposed on the larger region in a minority of cases. Positional gene enrichment analysis for 17q genes overexpressed in NB showed that dosage sensitive NB oncogenes are most likely located in the gained region immediately distal to the most distal breakpoint of the 2 breakpoint regions. Interestingly, comparison of gene expression profiles between primary tumors and normal fetal adrenal neuroblasts revealed 2 gene clusters on chromosome 17q that are overexpressed in NB, i.e. a region on 17q21.32 immediately distal to the most distal breakpoint (in cases with single regions of gain) and 17q24.1, a region coinciding with breakpoints leading to superimposed gain. © 2007 Wiley-Liss, Inc. [source] An interferon-sensitive response element is involved in constitutive caspase-8 gene expression in neuroblastoma cellsINTERNATIONAL JOURNAL OF CANCER, Issue 1 2007Alessandro De Ambrosis Abstract We previously identified a 1.2 Kb DNA element (P-1161/+16), 5, to caspase-8 exon-1, that acts as promoter in caspase-8-positive, but not in caspase-8-negative neuroblastoma (NB) cells. The P-1161/+16 DNA element regulates both constitutive and interferon IFN-,-inducible caspase-8 expression. Two GAS (IFN-activated sequence, STAT-1 binding site) and two ISRE (interferon sensitive response element, IRF binding site) were present in P-1161/+16. Deletion studies indicated that elements essential for promoter activity in NB cells were present in a 167 bp region 5, flanking exon-1 (P-151/+16), which contains an ISRE at position ,32. The transcription initiation site was mapped by 5, rapid amplification of cDNA end (RACE) at position ,20 from caspase-8 cDNA reference sequence. Disruption of the ISRE-32 indicated that it is required for both constitutive and IFN-,-inducible caspase-8 expression. IRF-1 and IRF-2 transcription factors bind to the (,151/+16) DNA fragment in vitro. Chromatin immunoprecipitation (ChIP) assays showed that IRF-1 and IRF-2 bind to the DNA region at the 5, of caspase-8 gene in NB cells, which show constitutive expression but not in caspase-8 negative cells. In these last cells, up-regulation of caspase-8 by IFN-, was associated to induction of IRF-1 and IRF-2 binding to caspase-8 promoter and increased histone acetylation. Moreover, RNA interference experiments also supported the involvement of IRF-1 and IRF-2 in constitutive caspase-8 expression in NB cells. © 2006 Wiley-Liss, Inc. [source] The von Hippel-Lindau tumor suppressor gene expression level has prognostic value in neuroblastomaINTERNATIONAL JOURNAL OF CANCER, Issue 3 2006Jasmien Hoebeeck Abstract Deletions of the short arm of chromosome 3 are often observed in a specific subset of aggressive neuroblastomas (NBs) with loss of distal 11q and without MYCN amplification. The critical deleted region encompasses the locus of the von Hippel-Lindau gene (VHL, 3p25). Constitutional loss of function mutations in the VHL gene are responsible for the VHL syndrome, a dominantly inherited familial cancer syndrome predisposing to a variety of neoplasms, including pheochromocytoma. Pheochromocytomas are, like NB, derived from neural crest cells, but, unlike NB, consist of more mature chromaffin cells instead of immature neuroblasts. Further arguments for a putative role of VHL in NB are its function as oxygen sensitizer and the reported relation between hypoxia and dedifferentiation of NB cells, leading to a more aggressive phenotype. To test the possible involvement of VHL in NB, we did mRNA expression analysis and sought evidence for VHL gene inactivation. Although no evidence for a classic tumor suppressor role for VHL in NB could be obtained, a strong correlation was observed between reduced levels of VHL mRNA and low patient survival probability (p = 0.013). Furthermore, VHL appears to have predictive power in NTRK1 (TRKA) positive tumor samples with presumed favorable prognosis, which makes it a potentially valuable marker for more accurate risk assessment in this subgroup of patients. The significance of the reduced VHL expression levels in relation to NB tumor biology remains unexplained, as functional analysis demonstrated no clear effect of the reduction in VHL mRNA expression on protein stability of its downstream target hypoxia-inducible factor ,. © 2006 Wiley-Liss, Inc. [source] Hybrid ARQ schemes for DS spread spectrum systems in the presence of narrow-band interferenceINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2002Abdulhameed M. Al-Sanie Abstract This paper is concerned with a direct sequence spread spectrum system making use of automatic repeat request (ARQ) schemes and operating in the presence of narrow-band (NB) interference and additive white Gaussian noise. In this study, we evaluate the system's throughput efficiency when a suppression filter is employed at the receiver to mitigate the effect of NB interference. Specifically, we investigate how the performance is influenced by various parameters such as the number of filter taps, processing gain, type of interference, and the signal power-to-interference power ratio. The simulation results show that using the suppression filter significantly improves the throughput performance of the hybrid ARQ schemes in the presence of NB interference. Copyright © 2002 John Wiley & Sons, Ltd. [source] DNA Index in childhood acute lymphoblastic leukaemia: a karyotypic method to validate the flow cytometric measurementINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2010P. RACHIERU-SOURISSEAU Summary The DNA index (DI) is a prognostic factor in childhood acute lymphoblastic leukemia (ALL). The accuracy of DI measurement is important for treatment stratification: hyperdiploidy with DI , 1.16 is predictive of favorable prognosis whereas hypodiploidy is associated with poor prognosis. The aim of this study was to validate the accuracy of the DI measured by flow cytometry (FCM) by comparison with the karyotype. From samples of 112 childhood ALL, we created a formula to calculate a theoretical DNA index (tDI) based on the blast cell karyotype, taking into account the additional or missing chromosome material of the major clone. FCM DI correlated with tDI calculated from karyotype (R = 0.987) and with modal chromosome number (DI = 0.0202 × Modal NB + 0.0675 and R = 0.984). In three cases a hypodiploid blast cell population was detected by FCM, while only the duplicated clone was identified by the karyotype. The strong correlation between tDI and DI validates the accuracy of FCM quantification, which is technically fast on fresh or frozen samples. If the karyotype is essential to analyze chromosomal abnormalities, FCM provides complementary information in aneuploid ALLs, either by confirming the cytogenetic data or by detecting additional clones not identified when only using cytogenetic data. [source] Copper(II) Triflate as a Source of Triflic Acid: Effective, Green Catalysis of Hydroalkoxylation ReactionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Mathieu J.-L. Abstract The hydroalkoxylation of dicyclopentadiene (DCPD) and norbornene (NB) with 2-hydroxyethyl methacrylate (HEMA) for the synthesis of industrially relevant monomers has been investigated with various metal-based Lewis acids and strong Brønsted acids. In the absence of other additives, copper(II) triflate is the most efficient catalyst system. Kinetics, electron spin resonance (ESR), catalyst poisoning and cross experiments indicate that triflic acid (TfOH) is the true active catalyst in these reactions. This in situ generation of TfOH occurs via reduction of Cu(OTf)2 by the olefin reagent (DCPD, NB). The copper ions present in the reaction mixture act as radical polymerization retardants, preventing polymerization of HEMA (which is observed with most other metal salts and strong Brønsted acids investigated), thus improving the selectivity and yield (up to 95%) for the desired products. These observations have led to the development of a highly effective green process, using bulk reagents (no solvent) and a cheap, metal-free catalyst system, based on TfOH and a phenolic radical inhibitor (2,5-di- tert -butylhydroxytoluene, BHT). [source] Long-term functional outcomes in patients with various types of orthotopic intestinal neobladderINTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2008Hideaki Miyake Objectives: To evaluate the long-term functional outcomes of various types of orthotopic neobladder (NB). Methods: Eighty-nine patients who underwent orthotopic NB reconstruction after radical cystectomy and were followed for at least 60 months after surgery were included in this retrospective study. The types of NB in this series were: modified Studer type, Hautmann type, Mainz type, Goldwasser type and modified Reddy type in 36, 9, 15, 10 and 19 patients, respectively. Results: Sixty-seven (75.3%) patients could void spontaneously, 15 (16.8%) voided with clean intermittent catheterization (CIC) assistance and seven (7.9%) with CIC alone. After excluding the seven voiding with CIC alone, daytime and night-time continence was achieved in 63 and 50 of the remaining 82 patients, respectively. In addition, the proportion of daytime continence in the modified Studer group was significantly greater than that in the Mainz group, whereas there was no significant difference in the proportion of night-time continence among these groups. Uroflow examination indicated that despite the lack of significant differences in the maximal flow rates and the voided volumes, the post-void residual in the modified Reddy group was significantly smaller than that in the modified Studer group. Blood gas analysis in the 82 patients showed that there were no significant differences in the pH, bicarbonate, chloride and base excess among these groups. Conclusions: Orthotopic NB created with intestinal segments generally has acceptable functional outcomes on long term follow up. These outcomes differ according to the type of NB. To define the optimal procedure for NB reconstruction, it is necessary to understand the long-term functional prospects, on which the subjective success of NB creation is based. [source] Analysis of the role of bacterial endospore cortex structure in resistance properties and demonstration of its conservation amongst speciesJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2001A. Atrih Aims: The aim of this work was to compare the chemical structure of the spore cortex of a range of species, and to determine any correlation between cortex structure and spore resistance properties. Methods and Results: The fine chemical structure of the cortex of Bacillus subtilis, Bacillus megaterium, Bacillus cereus and Clostridium botulinum was examined by muropeptide analysis using reverse phase HPLC. There is a conserved basic structure between peptidoglycan of these species, with the only difference being the level of de -N -acetylation of an amino sugar. In order to determine if an alteration in cortex structure correlates with heat resistance properties, the peptidoglycan structure and properties of B. subtilis spores prepared under different conditions were compared. Peptidoglycan from spores prepared in Nutrient Broth (NB) showed reduction in single L -alanine substituted muramic acid to only 13·9% compared with 20·6% in CCY-grown spores. NB-prepared spores are also unstable, with 161-fold less heat resistance (60 min, 85°C) and 43 times less Mn2+ content than CCY-grown spores. Addition of MnCl2 to NB led to a peptidoglycan profile similar to CCY-grown spores, sevenfold more heat resistance (60 min, 85°C) and an 86-fold increase in Mn2+ content. Addition of CCY salts to NB led all parameters to be comparable with CCY-grown spore levels. Conclusions: It has been shown that peptidoglycan structure is conserved in four spore-forming bacteria. Also, spore heat resistance is multifactorial and cannot be accounted for by any single parameter. Significance and Impact of the Study: Endospores made by diverse species most likely have common mechanisms of heat resistance. However, the molecular basis for their resistance remains elusive. [source] Enhancing Effect of Tob Deficiency on Bone Formation Is Specific to Bone Morphogenetic Protein-Induced Osteogenesis,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2002Michihiko Usui Abstract Tob is a recently reported novel bone morphogenetic protein (BMP) inhibitor, which originally was identified by West-Western procedure using ErbB2 as a probe and contains a nuclear localization signal. To further characterize the effects of Tob deficiency on BMP-induced new bone (NB) formation, we examined microcomputed tomography (,CT) on the cross-section of the bone induced by daily injection with BMP onto the calvariae of newborn mice. The calvariae of the saline-injected Tob-deficient (TD) mice were similar to those of the saline-injected or untreated wild-type (WT) mice. BMP injection locally produced NB on the calvaria in WT mice as known previously. In contrast to WT mice, BMP injection onto the calvariae of TD mice produced a calcified area in the cross-section of NB, which was more than that produced by BMP in the WT calvariae. In addition, the horizontal width and the vertical height of the NB induced by BMP in TD mice were several-fold more than those in WT mice. The effect of Tob deficiency on bone-forming activity was selective to the response to the injection with BMP because the levels of injury-induced NB formation examined by ,CT 10 days after bone marrow ablation in the femora were similar between the TD and WT mice. These data indicate that Tob acts as a novel specific antagonist against bone formation induced by BMP treatment in bone. [source] Detection of ciguatoxin in fish tissue using sandwich ELISA and neuroblastoma cell bioassayJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2008Cara Empey Campora Abstract The applicability of a new enzyme-linked immunoassay (ELISA) for detecting ciguatoxin (CTX) in fish tissue was evaluated by testing three fish species commonly implicated in ciguatera fish poisoning in Hawaii. A total of 164 individual almaco jack (Seriola rivoliana) and greater amberjack (S. dumerili) and a total of 175 individuals of the blue-spotted grouper (Cephalopholis argus) were caught at various locations in the Hawaiian Islands. Muscle tissue from each individual was assessed for the presence of CTX using two methods: a semi-quantitative ELISA that was recently developed for detecting picogram levels of CTX in fish extract and a neuroblastoma (NB) cell assay commonly used to screen for marine toxins in fish. Results of the tests were highly correlated, with the ELISA indicating the presence of CTX in 9.4% of all fish samples, and the NB assay indicating toxicity in 6.8% of the fish samples. We conclude that the ELISA produces reliable and accurate results that are consistent with those provided by the accepted NB assay and that the ELISA has potential for future applications in screening fish populations for CTX. J. Clin. Lab. Anal. 22:246,253, 2008. © 2008 Wiley-Liss, Inc. [source] Model development for semicontinuous production of ethylene and norbornene copolymers having uniform compositionAICHE JOURNAL, Issue 3 2009Shaojie Liu Abstract Terminal and penultimate models for controlling copolymer composition distribution (CCD) in ethylene and norbornene (NB) copolymerization were developed by taking into account the variation of active site concentration with the initial comonomer ratio. The models were validated by batch polymerization experimental data. The terminal model gave better correlation with the composition data whereas the penultimate model had a better fit to the rate data. The terminal model was then used to design NB feeding policies in semicontinuous processes for targeted CCD profiles. Based on the model results, a series of ethylene-NB copolymers with various NB contents were prepared. With the same NB content, the semicontinuous process produced a uniform composition, whereas the batch process yielded broad CCD. The batch samples had lower Tg values and broader transition ranges, even yielded crystalline materials. In contrast, the semicontinuous samples overcame the disadvantages. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] ECOSYSTEM MODELING: A TOOL TO UNDERSTAND THE INTERACTIONS BETWEEN EXTRACTIVE AND FED AQUACULTUREJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Yarish, C. 1, Rawson, Jr. M. V.2, Chopin, T.3, Wang, D. R.4, Chen, C.4, Carmona, R.1, Chen, C.5 , Wang, L.4, Ji , R.5 and Sullivan, J.5 1University of Connecticut, Stamford, Connecticut 06901-2315, USA; 2Georgia Sea Grant College Program, Athens, GA 30602-3636, USA; 3University of New Brunswick, Saint John, NB, E2L 4L5, Canada; 4Marine and Fishery Dept. of Hainan Province, Haikou, Hainan, P. R. China; 5The University of Georgia, Athens, GA 30602-3636, USA One of the most difficult tasks resource managers face is understanding the carrying capacity of coastal waters for aquaculture. Aquaculture, like many other human activities, can threaten coastal waters. Aquaculture producing shrimp and finfish depends on supplemental feeding and can contribute to eutrophication. A second type, involving shellfish and macroalgae, extracts plankton and nutrients from surrounding waters, and can have a significant positive impact on moderately eutrophic waters. Ecosystem modeling offers a 3-dimensional physical, chemical and biological simulation that can help understand and predict the impacts of aquaculture on coastal embayments. Such a model is being explored for Xincun Bay (22 km2), which is located in southeastern Hainan Province, China. Aquaculture in Xincun Bay includes 6500 fish pens, 100 ha of shrimp ponds, pearl oyster culture rafts and Kappaphycus alvarezii culture that produces 2,000 mt (Oct.-May). The surrounding area has ~ 15,000 people and Xincun City is a major offshore fishing and tourist center. The annual nitrogen and phosphorus removal capacity of Kappaphycus in Xincun Bay may have been in the order of 53.8 and 3.7 mt, respectively, during the 1999-2000 growing season. Lian Bay (~ 15 km2), a nearby bay with only Kappaphycus and pearl oyster culture (and little anthropogenic input), has a macroalgal production of 1,500 mt annually. The annual nitrogen and phosphorus removal capacity of Kappaphycus here may have been in the order of 25 and 0.33 mt, respectively. Our prototype model may hold the promise for showing the importance of integrating seaweed culture activities in the maintenance and health of coastal embayments. [source] Photoresponsive nanocarriers based on PAMAM dendrimers with a o -nitrobenzyl shellJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 3 2010Yan Li Abstract Gn (n = 3, 4, and 5) poly(amidoamine) (PAMAM) dendrimers were synthesized and peripherally modified with photocleavable o -nitrobenzyl (NB) groups by reacting o -nitrobenzaldehyde with the terminal amine groups of PAMAM dendrimers, followed by reducing the imine to amine groups with NaBH4. The NB-modified dendrimers, Gn-NB (n = 3, 4, and 5), were characterized by nuclear magnetic resonance and fourier transform infrared spectroscopy. The results showed that the NB groups were successfully attached on the periphery of the dendrimers with near 100% grafting efficiency. Such a photosensitive NB shell could be cut off on irradiation with 365 nm ultraviolet (UV) light. The encapsulation and release of guest molecules, that is, salicylic acid (SA) and adriamycin (ADR), by Gn-NB were explored. The encapsulation capability of these dendrimers was found to increase as the guest molecular size was decreased and have dependence on the generation of dendrimers as well. For both of SA and ADR, the average encapsulation numbers per dendrimer decreased in the order of G4-NB > G5-NB > G3-NB, indicating that the fourth generation dendrimer was a better container for the guest molecules. The rate of SA release was found to be greater with UV irradiation than that without, suggesting that the NB-shelled PAMMAM dendrimers could function as a molecular container/box with photoresponsive characteristics. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 551,557, 2010 [source] Ring-opening metathesis polymerization of amino acid-functionalized norbornene derivativesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2006Sutthira Sutthasupa Abstract Amino acid-derived novel norbornene derivatives, N,N,-(endo -bicyclo[2.2.1] hept-5-en-2,3-diyldicarbonyl) bis- L -alanine methyl ester (NBA), N,N,-(endo -bicyclo[2.2.1]hept-5-en-2,3-diyldicarbonyl) bis- L -leucine methyl ester (NBL), N,N,-(endo -bicyclo[2.2.1]hept-5-en-2,3-diyldicarbonyl) bis- L -phenylalanine methyl ester (NBF) were synthesized and polymerized using the Grubbs 2nd generation ruthenium (Ru) catalyst. Although NBA, NBL, and NBF did not undergo homopolymerization, they underwent copolymerization with norbornene (NB) to give the copolymers with Mn ranging from 5200 to 38,100. The maximum incorporation ratio of the amino acid-based unit was 9%, and the cis contents of the main chain were 54,66%. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5337,5343, 2006 [source] Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long-term Use In Vivo.JOURNAL OF PROSTHODONTICS, Issue 3 2008Part 1: Characterization of Adhesive Wear, Structure of Retaining Screws Abstract Purpose: The general aim of this study and those presented in Parts 2,4 of this series was to characterize the structure, properties, wear, and fracture of prosthetic retaining screws in fixed detachable hybrid prostheses after long-term use in vivo. This part of the overall investigation addresses whether there are differences in thread wear between the screws closest to the fulcrum and those that are farthest from the fulcrum in fixed detachable hybrid prostheses. Materials and Methods: The total number of prosthetic retaining screws used in this study was 100 (10 new and 90 used). New screws (controls) from Nobel Biocare (NB) were divided into Group 1 (slotted) and Group 2 (hexed). Ninety used screws (in service 18,120 months) were retrieved from fixed detachable hybrid prostheses in 18 patients (5 screws from each patient, 60 from NB and 30 from Sterngold). The used screws were divided into 18 groups. Additionally, each group was subdivided into A and B categories. Category A contained the middle three prosthetic screws, which were considered the farthest screws from the fulcrum line. Category B contained the most posterior two screws, which were considered the screws closest to the fulcrum line. All 100 screws were subjected to thorough, nondestructive testing. Results: Light and scanning electron microscopic examination of all used screws for each group revealed surface deterioration of the active profile of the screw threads consistent with adhesive wear. The observed thread profile deterioration ranged from mild to severe. The wear was aggressive enough to cause galling, which led to thinning of the threads and, in severe cases, to knife-edges at thread crests. In ten groups, the most anterior three screws exhibited more wear than the most posterior two screws. In addition to thread wear, severe plastic deformation was detected on the bottom part of each screw for three groups, and a long external longitudinal crack was detected in one screw of Group 2. Conclusions: The findings of this study and those presented in Parts 2,4 demonstrate that different retaining screws from the same manufacturer and/or from different manufacturers have different geometrical design, microstructures, major alloy constituents, and microhardness, and that these differences influence their preload and fractured load values. In this part of the overall investigation, the occurrence of galling as a result of wear involving prosthetic retaining screws appears to be an inevitable and unavoidable consequence of long-term use in vivo in fixed detachable hybrid prostheses regardless of the intended/original preload value. The galling rate is greater on the middle three screws compared to the most posterior two screws in fixed detachable hybrid prostheses. The wear pattern is consistent with an adhesive wear mechanism; however, this study does not provide enough data to support a definitive analysis. [source] Mechanical Behavior and Failure Analysis of Prosthetic Retaining Screws after Long-Term Use In Vivo.JOURNAL OF PROSTHODONTICS, Issue 3 2008Microhardness Analysis, Part 2: Metallurgical Abstract Purpose: This study involved testing and analyzing multiple retrieved prosthetic retaining screws after long-term use in vivo to: (1) detect manufacturing defects that could affect in-service behavior; (2) characterize the microstructure and alloy composition; and (3) further characterize the wear mechanism of the screw threads. Materials and Methods: Two new (control) screws from Nobel Biocare (NB) and 18 used (in service 18,120 months) retaining screws [12 from NB and 6 from Sterngold (SG)] were: (1) metallographically examined by light microscopy and scanning electron microscopy (SEM) to determine the microstructure; (2) analyzed by energy dispersive X-ray (EDX) microanalysis to determine the qualitative and semiquantitative average alloy and individual phase compositions; and (3) tested for Vickers microhardness. Results: Examination of polished longitudinal sections of the screws using light microscopy revealed a significant defect in only one Group 4 screw. No significant defects in any other screws were observed. The defect was considered a "seam" originating as a "hot tear" during original casting solidification of the alloy. Additionally, the examination of longitudinal sections of the screws revealed a uniform homogeneous microstructure in some groups, while in other groups the sections exhibited rows of second phase particles. The screws for some groups demonstrated severe deformation of the lower threads and the bottom part of the screw leading to the formation of crevices and grooves. Some NB screws were comprised of Au-based alloy with Pt, Cu, and Ag as alloy elements, while others (Groups 4 and 19) were Pd-based with Ga, Cu, and Au alloy elements. The microstructure was homogeneous with fine or equiaxed grains for all groups except Group 4, which appeared inhomogeneous with anomalous grains. SG screws demonstrated a typical dendritic structure and were Au-based alloy with Cu and Ag alloy elements. There were differences in the microhardness of gold alloy screws from NB and SG as well as palladium alloy screws from NB. Conclusions: Significant differences within NB retaining screws and between NB and SG screws were found for microstructure, major alloy constituents, and microhardness. [source] UVB in the management of early stage mycosis fungoidesJOURNAL OF THE EUROPEAN ACADEMY OF DERMATOLOGY & VENEREOLOGY, Issue 5 2006F Pavlotsky Background, Several options for treatment of early mycosis fungoides (MF) offer similar success rates. Previous small studies have shown UVB to be at least as effective as PUVA. Objective, To summarize our experience with UVB treatment of early MF. Methods, A retrospective analysis of early-stage MF patients treated by narrow band (NB) or broad band (BB) UVB in our institution between 1996 and 2002. Most patients achieving complete response (CR) were put on maintenance until natural sun exposure was possible and followed up every 3,6 months. The results were compared to those previously reported regarding PUVA. Results, Sixty-eight and 43 patients were treated by NB and BB UVB, respectively. Eighty-six per cent (84 and 89% in NB and BB UVB groups, respectively) of IA and 71% (78 and 44% in NB and BB UVB groups, respectively) of IB patients achieved CR within a mean of 12.8 and 10.6 weeks, respectively. When maintenance was stopped, 65 and 30% had not relapsed after an average follow up of 27 and 222 weeks, respectively. Non-relapse rate was 33 and 48% for those having had vs. those not having had maintenance, respectively. Conclusions, Our results are comparable to all previously reported for skin-targeted treatments, including PUVA and, to our belief, reflect the nature of early MF, in which CR can probably be achieved in most of the patients. Among the responding patients there is no relapse during prolonged follow-up in about one third of the cases. Thus, we believe treatment should be stopped completely following first CR induction and maintenance treatment should be considered for relapsing patients only. Both broad and narrow UVB options are good and future choices should be made on the basis of short- and long-term side-effects. [source] | ||||||||||||||||||||||||||||||||||||||||||||||