bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of silica reinforcement in CPE/NR blends by the use of rheological approaches
Authors: Phewphong Pakpum , Saeoui Pongdhorn , Sirisinha Chakrit 
Published: November 2007

AbstractBlends of elastomeric chlorinated polyethylene (CPE) and natural rubber (NR) at blend composition ratio of 80/20 CPE/NR with various precipitated silica loadings were prepared. By the use of rheological approaches, a mechanism of silica reinforcement was proposed. Results obtained reveal that the viscoelastic behavior of blends is influenced remarkably by loadings of silica. A cure promotion phenomenon is found as silica is loaded due probably to the strong silica‐CPE interaction and/or a reduction in curative absorption on silica surfaces. A strong Payne effect is observed, which is increased by a rise in silica loading, implying a formation of pseudocrosslink via a physical interaction, which could be disrupted at high strain of deformation. The proposed mechanism of silica reinforcement based on the formation of pseudocrosslink is validated by the deactivation of silanol groups on silica surfaces using silane‐coupling agents. The bis‐(3‐triethoxysilylpropyl) tetrasulfane (Si‐69) is found to be more effective in suppressing the pseudocrosslink than 3‐thiocyanatopropyl triethoxy silane (Si‐264), which is thought to be the result of its larger amount of alkoxy groups at a given silane loading. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Juvenile hormone and methyl farnesoate production in cockroach embryos in relation to dorsal closure and the reproductive modes of different species of cockroaches
Authors: Li Xinyi 
Published: November 2007

AbstractJuvenile hormone (JH), produced by the corpora allata (CA), is first detectable after dorsal closure, a conspicuous event in embryogenesis. The present research found that the timing of dorsal closure was consistently at about 45% of the total embryonic development time across most of the oviparous and ovoviviparous cockroach species examined. These included the ovoviviparous cockroaches Blaberus discoidalis, Byrsotria fumigata, Rhyparobia maderae, Nauphoeta cinerea, Phoetalia pallida, Schultesia lampyridiformis, and Panchlora nivea, as well as the oviparous cockroaches Blatta orientalis, Periplaneta americana, Eurycotis floridana, and Supella longipalpa. However, the only known viviparous cockroach Diploptera punctata completed dorsal closure at 20.8% of embryo development time. Methyl farnesoate (MF), the immediate precursor of JH III, is considered a functional molecule in crustaceans; however, in insects its function is still unclear. To understand the role of JH and MF in cockroach embryos, I compared JH and MF biosynthesis and release in several cockroach species of known phylogenetic relationships. Using a radiochemical assay, the present research showed that cockroach embryos representing all three reproductive modes produced and released both JH and MF, as previously shown for B. germanica, N. cinerea, and D. punctata. Members of a pair of embryonic CA from B. discoidalis, B. fumigata, R. maderae, and D. punctata were incubated with and without farnesol. MF accumulated in large amounts only in CA of R. maderae in the presence of farnesol, which indicates that control of the last step of biosynthesis of JH, conversion of MF into JH by MF epoxidase, is probably a rate‐limiting step in this species. Arch. Insect Biochem. Physiol. 66:159–168, 2007. © 2007 Wiley‐Liss, Inc.
Morphogenetic effects of alkaloidal metabolites on the development of the coremata in the salt marsh moth, Estigmene acrea (Dru.) (Lepidoptera: Arctiidae)
Authors: Jordan Alex T. , Jones Tappey H. , Conner William E. 
Published: November 2007

AbstractPyrrolizidine alkaloids (PAs) play a fundamental role in the sexual biology of the salt marsh moth Estigmene acrea. They are precursors for the male courtship pheromone hydroxydanaidal and they stimulate the growth and development of male pheromone‐disseminating organs called coremata. Yet larval Estigmene are polyphagous and feed only sporadically on PA‐containing plants and those they utilize contain different classes of PAs. The various PAs ingested are hydrolyzed to the common necine metabolite retronecine and re‐esterified to insect‐specific alkaloids from which the male pheromone hydroxydanaidal is synthesized. Given this complex metabolic pathway, we investigated the role of retronecine and the insect‐specific alkaloids that stem from it as morphogens stimulating corematal growth. Retronecine fed to terminal instar larvae in a standard caterpillar diet stimulated corematal growth. It also stimulated corematal growth when it was injected into the hemolymph of larvae. These results indicate that this common PA metabolite, and/or the insect specific alkaloids produced from it, function as corematal morphogens. The parental forms (alkaloids ingested from the plant) are not strictly necessary for corematal growth. Stimulation of the PA receptors on the galea and ingestion process are also not critical to corematal development. Since the insect‐specific alkaloids are the direct precursors for the male courtship pheromone, it is argued that their level is the best indicator of the ultimate pheromone titer and would provide the most accurate developmental signal. The effects of alkaloidal metabolites as morphogens in E. acrea are compared to those for the South Asian arctiines Creatonotus gangis and C. transiens in which the developmental role of PAs was first discovered. Arch. Insect Biochem. Physiol. 66:183–189, 2007. © 2007 Wiley‐Liss, Inc.
Evidence for two vitellogenin‐related genes in Leucophaea maderae: The protein primary structure and its processing
Authors: Tufail Muhammad , Bembenek Jadwiga , Elgendy Azza Mohamed , Takeda Makio 
Published: November 2007

AbstractWe previously reported a cDNA for vitellogenin (Vg) from the cockroach, Leucophaea maderae (Lm). In the present study, we identified another cDNA encoding a second Vg (Vg2) having stretches of amino acid sequences different from the first one, Vg1, reported earlier. The complete nucleotide sequence of Vg2 consisted of 5,915 bp, which encoded a primary protein of 1,911 residues including a 16‐residue putative signal peptide. The regions different in both Vg precursors (Pro‐Vg1 and pro‐Vg2) were four in number, and two, relatively longer, existed at the carboxy terminal. The presence of two Vg‐related cDNAs was confirmed by sequencing of RT‐PCR products generated using primers designed based on the common sequences flanking the regions different in amino acid sequences. Both forms were transcribed since they could be amplified on mRNA from fat bodies of different individual females. Southern blot analysis of digested genomic DNA revealed the existence of two Vg‐related genes in L. maderae indicating that each Vg cDNA originated from a separate gene. Also, the immunoblot analysis using antibodies generated against peptides unique to both Vg1 and Vg2 probed the same antigen in the same individual, suggesting LmVg to be a product coded by two different Vg precursors. Both Vg primary products showed 96% similarity at an amino acid level. Compared to other insect Vgs, Vg2 showed a slightly higher (1–2%) similarity than Vg1. We previously reported, based on amino‐terminal sequence analysis, that L. maderae pro‐Vg was cleaved into four subunit polypeptides (112‐, 100‐, 92‐, and 55‐kD), which were deposited in the egg as four respective vitellin (Vn) polypeptides. We show now based on immunoblot analysis that the 112‐kD polypeptide is further cleaved, near the C‐terminus, to an 87‐kD polypeptide before it is secreted into the hemolymph. Both the L. maderae Vgs were compared with each other and with other insect Vgs and the processing pattern is discussed. Arch. Insect Biochem. Physiol. 66:190–203, 2007. © 2007 Wiley‐Liss, Inc.
Analysis of mutant Ras proteins
Authors: Szeberényi József 
Published: November 2007

AbstractTerms to be familiar with before you start to solve the test: growth‐factor signaling; Ras proteins; Raf proteins; G proteins; protein kinases; GTPase; GEFs (guanine nucleotide exchange factors); GAPs (GTPase activating proteins); transfection; expression plasmid; mitogen‐activated protein kinase (MAPK); extracellular signal‐regulated kinase (ERK); constitutively active mutant; dominant inhibitory mutant.
Fabrication of CeO2 Nanoparticle Modified Glassy Carbon Electrode for Ultrasensitive Determination of Trace Amounts of Uric Acid in Urine
Authors: WEI Yan , LI Mao‐Guo , FANG Bin 
Published: November 2007

AbstractThe preparation of a glassy carbon electrode modified by CeO2 nanoparticles was described, which was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. In pH 6.0 buffer, the CeO2 nanoparticle modified electrode (CeO2 NP/GC) gave an excellent electrocatalytic activity for the oxidation of uric acid (UA). The catalytic current of UA versus its concentration had a good linear relation in the range of 2.0×10−7−5.0×10−4 mol/L, with the correlation coefficient of 0.9986 and detection limit of 1.0×10−7 mol/L. The modified electrode can be used for the determination of UA in urine, which can tolerate the interference of ascorbic acid up to 1000‐fold. The method was simple, quick and sensitive.
Kinetic Studies on the Lignin Peroxidase Catalyzed Oxidation of Veratryl Alcohol by H2O2 in AOT/Isooctane/Toluene/Water Reverse Micelles
Authors: LIU Jin‐Ting , HUANG Xi‐Rong , GAO Pei‐Ji 
Published: November 2007

AbstractThe steady state kinetics of the lignin peroxidase (LiP) catalyzed oxidation of veratryl alcohol (VA) by H2O2 in a sodium bis(2‐ethylhexyl) sulfosuccinate (AOT)/isooctane/toluene/water reverse micellar medium was studied and a comparison with the corresponding aqueous medium was made to understand the effect of the reverse micellar medium on the catalytic mechanism and kinetic parameters. Results indicated that the model reaction in the AOT reverse micelle followed the ping‐pong mechanism with true kcat, Km,VA and K being 59.6 min−1, 13.9 mmol· L−1 and 94.8 µmol·L−1, respectively; inhibition of high level of H2O2 on LiP followed the reversible competitive pattern with Ki being 0.140 mmol·L−1. The reaction mechanism and inhibition pattern in the AOT reverse micellar medium were the same as those in bulk aqueous medium, but the kinetic parameters except K were greatly different in the two media. The kcat and Ki values in the reverse micelle were approximately 2 and 20 times smaller than the corresponding values in the aqueous solution, but the Michaelis constant of VA was approximately 100 times greater than that in the aqueous solution. The above mentioned differences in the kinetic parameters were caused by the microheterogeneity and the interface of the AOT reverse micelle, which resulted in the partitioning of VA and H2O2, and by the changes of the conformation of LiP and the reactivity of the substrates.
Nitration Reaction Catalyzed by Horseradish Peroxidase in the Presence of H2O2 and NaNO2
Authors: DAI Rong‐Ji , HUANG Hui , CHEN Jie , DENG Yu‐Lin , XIAO Sheng‐Yuan 
Published: November 2007

AbstractThe enzymatic nitration of phenol and m‐cresol catalyzed by horseradish peroxidase was studied in the presence of H2O2 and NaNO2. The results showed that the nitration products of phenol were 2‐nitro and 4‐nitrophenols. There was also a small amount of by‐products of hydroquinone and catechol. The influences of various reaction parameters, including pH, organic solvent type, and concentrations of NaNO2 and H2O2, on the nitration products were investigated. The yields of 4‐nitrophenol and 2‐nitrophenol were 14% and 12%, respectively. The nitration products of m‐cresol were 4‐nitro‐m‐cresol and 6‐nitro‐m‐cresol, and the yields of 4‐nitro‐m‐cresol and 6‐nitro‐m‐cresol were 19% and 30%, respectively.
Preparation of a Star Network PEG‐based Gel Polymer Electrolyte and Its Application to Electrochromic Devices
Authors: GONG Yong‐Feng , FU Xiang‐Kai , ZHANG Shu‐Peng , JIANG Qing‐Long 
Published: November 2007

AbstractA star network polymer with a pentaerythritol core linking four PEG‐block polymeric arms was synthesized, and its corresponding gel polymer electrolyte based on lithium perchlorate and plasticizers EC/PC with the character being colorless and highly transparent has been also prepared. The polymer host was characterized and confirmed to be of a star network and an amorphous structure by FTIR, 1H NMR and XRD studies. The polymer host hold good mechanical properties for pentaerythritol cross‐linking. Maximum ionic conductivity of the prepared polymer electrolyte has reached 8.83×10−4 S·cm−1 at room temperature. Thermogravimetry (TG) of the polymer electrolyte showed that the thermal stability was up to at least 150 °C. The gel polymer electrolyte was further evaluated in electrochromic devices fabricated by transparent PET‐ITO and electrochromically active viologen derivative films, and its excellent performance promised the usage of the gel polymer electrolyte as ionic conductor material in electrochromic devices.
Prospective analysis of carotid artery flow in breast cancer patients treated with supraclavicular irradiation 8 or more years previously
Authors: Woodward Wendy A. , Durand Jean B. , Tucker Susan L. , Strom Eric A. , Perkins George H. , Oh Julia , Arriaga Lisa , Domain Delora , Buchholz Thomas A. 
Published: November 2007

AbstractBACKGROUND.To the authors' knowledge, the effects of supraclavicular fossa radiation on the carotid artery are not well described. In the current study, the authors performed a prospective study to examine the long‐term risk of carotid artery stenosis after supraclavicular irradiation for breast cancer.METHODS.A total of 46 breast cancer patients who were treated with adjuvant radiation to the supraclavicular fossa with >8 years of follow‐up underwent bilateral Doppler imaging of the carotid artery. Two independent cardiologists interpreted each ultrasound study with no knowledge of which side was treated.RESULTS.The median follow‐up from the date of diagnosis was 14.6 years and the mean patient age at the time of ultrasound was 55 years. The median prescribed dose to the supraclavicular fossa was 50 grays. Four patients were found to have clinically relevant, asymptomatic carotid stenosis, for which a cardiology referral was necessary. Only 1 of these 4 patients had stenosis involving the irradiated carotid artery only; 1 patient had bilateral stenosis and 2 patients had only contralateral stenosis. There was no difference noted with regard to isolated ipsilateral versus contralateral medial intimal thickening of the carotid artery (5 patients vs 6 patients, respectively). Furthermore, there were no differences noted with regard to ipsilateral versus contralateral peak systolic flow in the internal (83.5 vs 85.6 cm/seconds; P = .522 by the Student t test and P = .871 by the signed rank test) or common (74.4 vs 77.0 cm/seconds; P = .462 by the Student t test and P = .246 by the signed rank test) carotid artery.CONCLUSIONS.In this prospective study of breast cancer patients with long follow‐up, there was no evidence of late, clinically relevant stenosis, increased intimal thickening, or increased peak systolic carotid artery flow secondary to supraclavicular irradiation. Cancer 2008. © 2007 American Cancer Society.
A coagulation factor becomes useful in the study of acute leukemias: Studies with blood coagulation factor XIII
Authors: Kiss Flóra , Simon Ágnes , Csáthy László , Hevessy Zsuzsanna , Katona Éva , Kiss Csongor , Kappelmayer János 
Published: November 2007

AbstractThe intracellular form of the coagulation factor XIII has previously been identified by immunomorphological techniques using polyclonal antibodies. In these studies, only the A subunit (FXIII‐A) was detectable in megakaryocytes/platelets and in monocytes/macrophages. We developed several novel monoclonal antibody clones directed to both subunits (FXIII‐A and FXIII‐B) and investigated their appearance in normal and leukemic cells. By using 3‐ and 4‐color flow cytometry FXIII expression was investigated in normal peripheral blood and bone marrow samples and in acute myeloblastic (AML) and lymphoblastic (ALL) leukemia cases. Samples were studied by Western blotting and confocal laser scanning microscopy. With a previously published ELISA assay applying two monoclonal antibodies directed to different epitopes in FXIII‐A, we were able to measure the intracytoplasmic content of FXIII‐A in normal cells and leukemic blasts. FXIII‐A was detectable in normal peripheral blood monocytes and in large quantities in platelets, but both cell types were negative for FXIII‐B. There was no surface staining for FXIII‐A, it only appeared intracellularly. In samples derived from patients with AML M4 and M5, FXIII‐A sensitively identified blast cells. Although normal lymphocytes do not express FXIII‐A, 40% of ALL cases showed significant FXIII‐A expression as determined by flow cytometry. FXIII‐A positivity of lymphoblasts was verified by Western blotting, ELISA, and confocal laser scanning microscopy cytometry. These data provide evidence that FXIII‐A is a sufficiently sensitive marker in differentiating myeloblasts and monoblasts and is suitable for identifying leukemia‐associated phenotypes in ALL. © 2007 International Society for Analytical Cytology
Cell microarray platform for anticancer drug development
Authors: Lee Min‐Jung , Chung Eun Joo , Lee Sunmin , Chung Joon‐Yong , Telford William G. , Sausville Edward A. , Gojo Ivana , Karp Judith E. , Gore Steven D. , Kapoor Veena , Kim Yeong Sang , Kummar Shivaani , Gutierrez Martin , Hewitt Stephen M. , Trepel Jane B. 
Published: November 2007

AbstractPharmacodynamic assessment of whether a drug has interacted with and modified its target is an essential component of molecularly targeted clinical trials. Although many trials are written with the intent to assess tumor biopsies, if available, thus far the great majority of early drug trials have used peripheral blood mononuclear cells (PBMC) as a tumor surrogate. Typically, PBMC are studied by low‐throughput techniques such as Western blot. We present the use of a cell‐based tissue microarray for assessment of anticancer drug activity in vivo. We demonstrate the utility of this technique for analysis of protein hyperacetylation in response to treatment with the histone deacetylase inhibitor, SNDX‐275 in PBMC treated in vitro and in PBMC and bone marrow aspirates from patients in Phase I clinical trials with SNDX‐275. We demonstrate that the cell microarray can be used to measure drug response in a high‐throughput manner, allowing analysis of an entire trial on one or two glass slides. The cell microarray technique brings the advantages of the tissue microarray platform to the pharmacodynamic assessment of single cells, such as those isolated from bone marrow aspirates, fine needle aspirates, or malignant effusions, and to analysis of PBMC, the most commonly studied surrogate in oncology trials. Drug Dev Res 68:226–234, 2007. Published 2007 Wiley‐Liss, Inc.
Ganglion cell regeneration following whole‐retina destruction in zebrafish
Authors: Sherpa Tshering , Fimbel Shane M. , Mallory Dianne E. , Maaswinkel Hans , Spritzer Scott D. , Sand Jordan A. , Li L. , Hyde David R. , Stenkamp Deborah L. 
Published: November 2007

AbstractThe retinas of adult teleost fish can regenerate neurons following injury. The current study provides the first documentation of functional whole retina regeneration in the zebrafish, Danio rerio, following intraocular injection of the cytotoxin, ouabain. Loss and replacement of laminated retinal tissue was monitored by analysis of cell death and cell proliferation, and by analysis of retina‐specific gene expression patterns. The spatiotemporal process of retinal ganglion cell (RGC) regeneration was followed through the use of selective markers, and was found to largely recapitulate the spatiotemporal process of embryonic ganglion cell neurogenesis, over a more protracted time frame. However, the re‐expression of some ganglion cell markers was not observed. The growth and pathfinding of ganglion cell axons was evaluated by measurement of the optic nerve head (ONH), and the restoration of normal ONH size was found to correspond to the time of recovery of two visually‐mediated behaviors. However, some abnormalities were noted, including overproduction of RGCs, and progressive and excessive growth of the ONH at longer recovery times. This model system for whole‐retina regeneration has provided an informative view of the regenerative process. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Prenatal corticosteroid exposure affects hippocampal plasticity and reduces lifespan
Authors: Noorlander C.W. , Visser G.H.A. , Ramakers G.M.J. , Nikkels P.G.J. , de Graan P.N.E. 
Published: November 2007

AbstractSynthetic corticosteroids, such as dexamethasone, are frequently administered to pregnant women at risk for preterm delivery. Endogenous corticosteroids are essential for normal development, but exposure to therapeutic doses at critical developmental stages may have adverse effects on the central nervous system. Major concern has arisen about long‐term effects of corticosteroid treatment on brain plasticity, particularly in the hippocampus. Therefore, we analyzed the molecular, cellular, and behavioral effects of prenatal dexamethasone treatment on the adult hippocampus. Pregnant mice were treated at embryonic day 15.5 with a single dose of dexamethasone or saline. Adult offspring was analyzed for hippocampal neuron loss, cell proliferation, and NMDA receptor subunit expression. Hippocampal function was assessed in the Morris water maze and synaptic plasticity in the CA1 field by determining frequency dependence of LTP and LTD in hippocampal slices. Prenatal dexamethasone treatment decreased hippocampal cell proliferation in the dentate gyrus. Treated mice showed reduced LTD, impaired spatial learning, and a marked reduction in lifespan. Our data show long‐term adverse effects of prenatal dexamethasone treatment on hippocampal function in mice and suggest accelerated aging. These findings indicate that it is important to be restrictive with corticosteroid administration during fetal development because of the lifelong consequences. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008
Otoc1: A novel otoconin‐90 ortholog required for otolith mineralization in zebrafish
Authors: Petko Jessica A. , Millimaki Bonny B. , Canfield Victor A. , Riley Bruce B. , Levenson Robert 
Published: November 2007

AbstractWithin the vestibular system of virtually all vertebrate species, gravity and linear acceleration are detected via coupling of calcified masses to the cilia of mechanosensory hair cells. The mammalian ear contains thousands of minute biomineralized particles called otoconia, whereas the inner ear of teleost fish contains three large ear stones called otoliths that serve a similar function. Otoconia and otoliths are composed of calcium carbonate crystals condensed on a core protein lattice. Otoconin‐90 (Oc90) is the major matrix protein of mammalian and avian otoconia, while otolith matrix protein (OMP) is the most abundant matrix protein found in the otoliths of teleost fish. We have identified a novel gene, otoc1, which encodes the zebrafish ortholog of Oc90. Expression of otoc1 was detected in the ear between 15 hpf and 72 hpf, and was restricted primarily to the macula and the developing epithelial pillars of the semicircular canals. Expression of otoc1 was also detected in epiphysis, optic stalk, midbrain, diencephalon, flexural organ, and spinal cord. During embryogenesis, expression of otoc1 mRNA preceded the appearance of omp‐1 transcripts. Knockdown of otoc1 mRNA translation with antisense morpholinos produced a variety of aberrant otolith phenotypes. Our results suggest that Otoc1 may serve to nucleate calcium carbonate mineralization of aragonitic otoliths. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2008