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Selected Abstracts2423: Compartment syndrome in glaucoma damage, a new hypothesis?ACTA OPHTHALMOLOGICA, Issue 2010S ORGUL Purpose To evaluate the potential similarities in pathophysiology between non-arteritic anterior ischemic optic neuropathy (AION) and primary open-angle glaucoma (POAG). Methods The currently accepted views of the pathophysiology of AION and general understanding of the clinical picture of this ischemic condition were reviewed. Based on the hypothesis of the group in Wisconsin, who postulated a compartment syndrome of the anterior optic nerve within the tight anatomical structures of the lamina cribrosa, parallels were drawn for glaucomatous optic neuropathy, and a new hypothesis for the pathogenesis of the latter condition was suggested. Results The tight structures around, but also within the "disk at risk" observed in a majority of patients with AION are well compatible with the hypothesis of a compartment syndrome. Similar conditions may result from the restructuring process within the lamina cribrosa in POAG and lead to locally limited, but repeated "AION-like" processes, explaining why some patients progress despite reduced intraocular pressure. Conclusion The pathophysiology of POAG, especially in advanced cases, and AION seem to present similarities, which need to be better understood. [source] Linear and whorled nevoid hypermelanosis associated with developmental delay and generalized convulsionsINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2004Ahmad A. Alrobaee MD A 2-year-old Saudi boy was seen in our dermatology clinic with symmetrical, brown, linear macules over the legs, trunk, and arms (Figs 1,3). He was a product of a full-term vaginal delivery following an uneventful first pregnancy in a 22-year-old mother. The birth weight was 2.3 kg. The hyperpigmented macules followed the lines of Blaschko and were noticed a few months after birth; they had enlarged with body growth until the age of 18 months. There was no family history of a similar condition and the boy's parents were unrelated. No blistering or inflammatory changes preceded the hyperpigmentation. The palms, soles, nails, scalp, mucous membranes, and teeth were normal. In addition to the hyperpigmented macules, the patient started to have generalized convulsions at the age of 2 months. Figure 1. Linear hyperpigmented macules following the lines of Blaschko Figure 2. Close up view of the hyperpigmented macules Figure 3. Trunk: Hyperpigmented macules in whorled distribution Physical examination revealed delayed developmental milestones, microphthalmia, depressed nose, and high arched palate with no other abnormalities. Blood tests were normal. Magnetic resonance imaging of the brain showed changes suggestive of a demyelinating process at the parieto-occipital white matter. Echocardiography revealed an atrial septal defect. Electroretinography (ERG), visual evoked potentials (VEP), and auditory evoked potentials (AEP) were normal. Electroencephalogram (EEG) showed multifocal epileptic discharge in the posterior region. A punch skin biopsy taken from the hyperpigmented lesions showed an increase in the melanin content of the basal layer with no incontinence of pigment or melanophages in the dermis. [source] Inositol hexaphosphate downregulates both constitutive and ligand-induced mitogenic and cell survival signaling, and causes caspase-mediated apoptotic death of human prostate carcinoma PC-3 cells,MOLECULAR CARCINOGENESIS, Issue 1 2010Mallikarjuna Gu Abstract Constitutively active mitogenic and prosurvival signaling cascades due to aberrant expression and interaction of growth factors and their receptors are well documented in human prostate cancer (PCa). Epidermal growth factor (EGF) and insulin-like growth factor-1 (IGF-1) are potent mitogens that regulate proliferation and survival of PCa cells via autocrine and paracrine loops involving both mitogen-activated protein kinase (MAPK)- and Akt-mediated signaling. Accordingly, here we assessed the effect of inositol hexaphosphate (IP6) on constitutive and ligand (EGF and IGF-1)-induced biological responses and associated signaling cascades in advanced and androgen-independent human PCa PC-3 cells. Treatment of PC-3 cells with 2,mM IP6 strongly inhibited both growth and proliferation and decreased cell viability; similar effects were also observed in other human PCa DU145 and LNCaP cells. IP6 also caused a strong apoptotic death of PC-3 cells together with caspase 3 and PARP cleavage. Mechanistic studies showed that biological effects of IP6 were associated with inhibition of both constitutive and ligand-induced Akt phosphorylation together with a decrease in total Akt levels, but a differential inhibitory effect on MAPKs extra cellular signal-regulated kinase 1/2 (ERK1/2), c- Jun N-terminal protein kinase (JNK1/2), and p38 under constitutive and ligand-activated conditions. Under similar condition, IP6 also inhibited AP-1 DNA-binding activity and decreased nuclear levels of both phospho and total c-Fos and c- Jun. Together, these findings for the first time establish IP6 efficacy in inhibiting aberrant EGF receptor (EGFR) or IGF-1 receptor (IGF-1R) pathway-mediated sustained growth promoting and survival signaling cascades in advanced and androgen-independent human PCa PC-3 cells, which might have translational implications in advanced human PCa control and management. © 2009 Wiley-Liss, Inc. [source] Planum parietale of chimpanzees and orangutans: A comparative resonance of human-like planum temporale asymmetryTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 1 2005Patrick J. Gannon Abstract We have previously demonstrated that leftward asymmetry of the planum temporale (PT), a brain language area, was not unique to humans since a similar condition is present in great apes. Here we report on a related area in great apes, the planum parietale (PP). PP in humans has a rightward asymmetry with no correlation to the L>R PT, which indicates functional independence. The roles of the PT in human language are well known while PP is implicated in dyslexia and communication disorders. Since posterior bifurcation of the sylvian fissure (SF) is unique to humans and great apes, we used it to determine characteristics of its posterior ascending ramus, an indicator of the PP, in chimpanzee and orangutan brains. Results showed a human-like pattern of R>L PP (P = 0.04) in chimpanzees with a nonsignificant negative correlation of L>R PT vs. R>L PP (CC = ,0.3; P = 0.39). In orangutans, SF anatomy is more variable, although PP was nonsignificantly R>L in three of four brains (P = 0.17). We have now demonstrated human-like hemispheric asymmetry of a second language-related brain area in great apes. Our findings persuasively support an argument for addition of a new component to the comparative neuroanatomic complex that defines brain language or polymodal communication areas. PP strengthens the evolutionary links that living great apes may offer to better understand the origins of these progressive parts of the brain. Evidence mounts for the stable expression of a neural foundation for language in species that we recently shared a common ancestor with. © 2005 Wiley-Liss, Inc. [source] Comparative Overview of Cardiac Output Measurement Methods: Has Impedance Cardiography Come of Age?CONGESTIVE HEART FAILURE, Issue 2 2000Anthony N. De Maria MD Cardiac output, usually expressed as liters of blood ejected by the left ventricle per minute, is a fundamental measure of the adequacy of myocardial function to meet the perfusion needs of tissue at any time. Decreases in cardiac output over time (when cardiac output is measured under similar conditions) may signal myocardial functional deterioration and the onset or progression of heart failure. Conversely, improvements in cardiac output may indicate a positive response to medical therapy. However, most methods for evaluating cardiac output are technically demanding, require specialized training and specialized environments for measurement, and are costly. Therefore, most measurement techniques are impractical for routine evaluation of disease progression and/or response to treatment in the prevention and/or management of heart failure. This paper provides a comparative overview of commonly employed cardiac output measurement strategies with emphasis on developments in impedance cardiography which suggest that impedance cardiography has the potential to make routine assessment and trending of cardiac output a viable alternative to assist in the management of both chronically and acutely ill patients, including those with heart failure. [source] Spatial variation in population density across the geographical range in helminth parasites of yellow perch Perca flavescensECOGRAPHY, Issue 5 2007Robert Poulin The abundance of a species is not constant across its geographical range; it has often been assumed to decrease from the centre of a species' range toward its margins. The central assumption of this "favourable centre" model is tested for the first time with parasites, using different species of helminth parasites exploiting fish as definitive hosts. Data on prevalence (percentage of hosts that are infected) and abundance (mean no. parasites per host) were compiled for 8 helminth species occurring in 23 populations of yellow perch Perca flavescens, from continental North America. For each parasite species, correlations were computed between latitude and both local prevalence and abundance values. In addition, the relationships between the relative prevalence or abundance in one locality and the distance between that locality and the one where the maximum value was reported, were assessed separately for each species to determine whether abundance tends to decrease away from the presumed centre of the range, where it peaks. For both the cestode Proteocephalus pearsei and the acanthocephalan Leptorhynchoides thecatus, there was a positive relationship between prevalence or abundance and the latitude of the sampled population. There was also a significant negative relationship between relative prevalence and the distance from the locality showing the maximum value in P. pearsei, but no such pattern was observed for the other 7 parasite species. Since this single significant decrease in prevalence with increasing distance from the peak value may be confounded by a latitudinal gradient, it appears that the distribution of abundance in parasites of perch does not follow the favourable centre model. This means that the environmental variables affecting the density of parasites (host availability, abiotic conditions) do not show pronounced spatial autocorrelation, with nearby sites not necessarily providing more similar conditions for the growth of parasite populations than distant sites. [source] Numerical simulation of DNA sample preconcentration in microdevice electrophoresisELECTROPHORESIS, Issue 6 2005Alok Srivastava Abstract A numerical model is presented for the accurate and efficient prediction of preconcentration and transport of DNA during sample introduction and injection in microcapillary electrophoresis. The model incorporates conservation laws for the different buffer ions, salt ions, and DNA sample, coupled through a Gaussian electric field to account for the field modifications that cause electromigration. The accuracy and efficiency required to capture the physics associated with such a complex transient problem are realized by the use of the finite element-flux corrected transport (FE-FCT) algorithm in two dimensions. The model has been employed for the prediction of DNA sample preconcentration and transport during electrophoresis in a double-T injector microdevice. To test its validity, the numerical results have been compared with the corresponding experimental data under similar conditions, and excellent agreement has been found. Finally, detailed results from a simulation of DNA sample preconcentration in electrophoretic microdevices are presented using as parameters the electric field strength and the other species concentrations. The effect of the Tris concentration on sample stacking is also investigated. These results demonstrate the great potential offered by the model for future optimization of such microchip devices with respect to significantly enhanced speed and resolution of sample separation. [source] A microfabricated hybrid device for DNA sequencingELECTROPHORESIS, Issue 21 2003Shaorong LiuArticle first published online: 6 NOV 200 Abstract We have created a hybrid device of a microfabricated round-channel twin-T injector incorporated with a separation capillary in order to extend the straight separation distance for high speed and long readlength DNA sequencing. Semicircular grooves on glass wafers are obtained using a photomask with a narrow line-width and a standard isotropic photolithographic etching process. Round channels are made when two etched wafers are face-to-face aligned and bonded. A two-mask fabrication process has been developed to make channels of two different diameters. The twin-T injector is formed by the smaller channels whose diameter matches the bore of the separation capillary, and the "usual" separation channel, now called the connection channel, is formed by the larger ones whose diameter matches the outer diameter of the separation capillary. The separation capillary is inserted through the connection channel all the way to the twin-T injector to allow the capillary bore flush with the twin-T injector channels. The total dead-volume of the connection is estimated to be , 5 pL. To demonstrate the efficiency of this hybrid device, we have performed four-color DNA sequencing on it. Using a 200 ,m twin-T injector coupled with a separation capillary of 20 cm effective separation distance, we have obtained readlengths of 800 plus bases at an accuracy of 98.5% in 56 min, compared to about 650 bases in 100 min on a conventional 40 cm long capillary sequencing machine under similar conditions. At an increased separation field strength and using a diluted sieving matrix, the separation time has been reduced to 20 min with a readlength of 700 bases at 98.5% base-calling accuracy. [source] Synthetic bacterial lipopeptide analogs facilitate naive CD4+ T,cell differentiation and enhance antigen-specific HLA-II-restricted responsesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2005Mascia Ghielmetti Abstract Synthetic di- and tri-palmitoylated bacterial lipopeptide analogs (BLpA) can enhance HLA-I-restricted immune responses. Here we show that BLpA indirectly promote antigen-driven differentiation of naive CD4+ T,lymphocytes in vitro, with mechanisms that require DC and are inhibited by CTLA-4/Ig. In mixed cultures of cord blood-derived PBMC and allogeneic DC, P3CSK4 lipopeptide facilitated the transition from CCR7+/CD45RA+/CD62L+ to CCR7,/CD45RA,/CD62Ldim T,cells with kinetics significantly exceeding those obtained with the unlipidated CSK4 analog. Moreover, P3CSK4 and P2CSK4, but neither the mono-palmitoylated PCSK4 analog nor the CSK4 peptide, increased the frequency of IFN-,-producing T,cells expanded under similar conditions. Along with this, P2CSK4 and P3CSK4, but not PCSK4, restored the in vitro antigenicity of MDP-OspA, a non-immunogenic analog of Borrelia burgdorferi major outer surface lipoprotein,A, and enhanced the frequency of in vitro expanded T,cells specific for the tetanus toxoid (TT) and hepatitis,B surface antigen (HBsAg) peptides TT947,967 and HBsAg19,33 and for TT. Altogether, BLpA bearing at least two ester-bonded palmitoyl side chains indirectly enhance antigen-driven CD4+ T,cell differentiation. BLpA adjuvanticity is independent of covalent bonding to Ag and Ag formulation. This information may be helpful to generate more potent recombinant vaccines. [source] Demonstration of strong enterobacterial reactivity of CD4+CD25, T,cells from conventional and germ-free mice which is counter-regulated by CD4+CD25+ T,cellsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2004Monika Gad Abstract Unfractionated CD4+ T,cells from the gut-associated lymphoid tissue (GALT) and peripheral lymph nodes are unresponsive when exposed to enterobacterial antigens in vitro. Under similar conditions, CD4+ T,cells depleted in vivo or in vitro of CD4+CD25+ T,cells proliferate extensively. The CD4+CD25, T,cell reactivity depends on MHC class,II presentation, specific TCR stimulation, CD4 ligation, and antigen processing by antigen-presenting cells. The CD4+CD25, T,cells respond to autologousand heterologous enterobacterial antigens, but not to antigens from the feces of germ-free mice. Surprisingly, CD4+CD25, T,cells obtained from the GALT of germ-free mice also proliferate when exposed to enterobacterial antigens, and adding back the conventional or germ-free CD4+CD25+ T,cells to the enteroantigen-stimulated CD4+CD25, T,cells abolishes proliferation. As judged from carboxyfluorescein diacetate succinimidyl ester-labeling experiments, 4,5% of the CD4+CD25, T,cells respond to enteroantigen. The data show for the first time that CD4+CD25, T,cells with reactivity towards the enterobacterial flora and regulatory CD4+CD25+ T,cells are present in both conventional and germ-free mice. The data suggest that a significant proportion of the peripheral pool of CD4+CD25, T,cells express anti-enterobacterial reactivity, which, due to the presence of regulatory CD4+CD25+ T,cells, is kept in a quiescent state. [source] Structure and promoter analysis of the mouse membrane-bound transferrin-like protein (MTf) geneFEBS JOURNAL, Issue 5 2001Kazuko Nakamasu Recently, we purified membrane-bound transferrin-like protein (MTf) from the plasma membrane of rabbit chondrocytes and showed that the expression levels of MTf protein and mRNA were much higher in cartilage than in other tissues [Kawamoto T, Pan, H., Yan, W., Ishida, H., Usui, E., Oda, R., Nakamasu, K., Noshiro, M., Kawashima-Ohya, Y., Fujii, M., Shintani, H., Okada, Y. & Kato, Y. (1998) Eur. J. Biochem.256, 503,509]. In this study, we isolated the MTf gene from a constructed mouse genomic library. The mouse MTf gene was encoded by a single-copy gene spanning ,,26 kb and consisting of 16 exons. The transcription-initiation site was located 157 bp upstream from the translation-start codon, and a TATA box was not found in the 5, flanking region. The mouse MTf gene was mapped on the B3 band of chromosome 16 by fluorescence in situ hybridization. Using primary chondrocytes, SK-MEL-28 (melanoma cell line), ATDC5 (chondrogenic cell line) and NIH3T3 (fibroblast cell line) cells, we carried out transient expression studies on various lengths of the 5, flanking region of the MTf gene fused to the luciferase reporter gene. Luciferase activity in SK-MEL-28 cells was higher than in primary chondrocytes. Although no luciferase activity was detectable in NIH3T3 cells, it was higher in chondrocytes than in ATDC5 chondrogenic cells. These findings were consistent with the levels of expression of MTf mRNA in these cells cultured under similar conditions. The patterns of increase and decrease in the luciferase activity in chondrocytes transfected with various 5, deleted constructs of the MTf promoter were similar to that in ATDC5 cells, but differed from that in SK-MEL-28 cells. The findings obtained with primary chondrocytes suggest that the regions between ,693 and ,444 and between ,1635 and ,1213 contain positive and negative cis -acting elements, respectively. The chondrocyte-specific expression of the MTf gene could be regulated via these regulatory elements in the promoter region. [source] Exploiting a Dual-Fluorescence Process in Fluorene,Dibenzothiophene- S,S -dioxideCo-Polymers to Give Efficient Single Polymer LEDs with Broadened EmissionADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Simon M. King Abstract A description of the synthesis of random (9,9-dioctylfluorene-2,7-diyl),(dibenzothiophene- S,S -dioxide-3,7-diyl) co-polymers (p(F-S)x) by palladium-catalyzed Suzuki cross-coupling polymerization where the feed ratio of the latter is varied from 2 to 30,mol % (i.e., x,=,2,30) is given. Polymer light emitting devices are fabricated with the configuration indium tin oxide/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid)/p(F,S)x/Ba/Al. The device external quantum efficiency increased as the ratio of the S co-monomer was increased, up to a maximum of 1.3% at 100,mA cm,2 for p(F-S)30 and a brightness of 3 770,cd m,2 (at 10,V). The S units impart improved electron injection, more balanced mobilities, and markedly improved device performance compared to poly(9,9-dioctylfluorene) under similar conditions. These co-polymers display broad emission, observed as greenish-white light, which arises from dual fluorescence, viz. both local excited states and charge transfer states. Utilizing dual emission can reduce problems associated with Förster energy transfer from high-energy to-low energy excited states. [source] Investigation on the characteristics of boiling heat transfer through narrow annular channelsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 2 2005Su Shun-yu Abstract Factors concerning the characteristics of boiling heat transfer are analyzed theoretically. Based on the experimental data of boiling heat transfer through annular channels with the gaps of 1,2 mm, three correlations which will be used to calculate the heat transfer in the similar conditions are given. The results obtained from these correlations are compared with experimental data. The main factors having influence on boiling heat transfer through narrow channels, and the desirable correlation are determined. This correlation can be used to predict the flow boiling heat transfer within the range of this experiment. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(2): 78,84, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20049 [source] 5-Chloro-3-methylthio-1,2,4-thiadiazol-2-ium chlorides as useful synthetic precursors to a variety of 6a,4 -thiapentalene systemsHETEROATOM CHEMISTRY, Issue 1 2003Georges Morel Title salts 3 were easily obtained by treatment of formimidoyl isothiocyanates 1 with a twofold excess of methanesulfenyl chloride. They showed interesting chemical behavior toward several nitrogen and carbon nucleophiles. Substitution reactions with isothioureas and acetamide in the presence of triethylamine gave the 1H, 6H -6a,4 -thia-1,3,4,6-tetraazapentalenes 7 and 6H -6a,4 -thia-1-oxa-3,4,6-triazapentalene 9, respectively. Addition of p -toluidine furnished the 5-imino-thiadiazole derivatives 10, which reacted further with diverse heterocumulenes to yield the corresponding thiatriaza- and tetraazapentalene species 11. The N,N,-bis(1,2,4-thiadiazol-5-ylidene)diaminobenzenes 13 were also prepared and reacted with phenyl isothiocyanate. Two stable rotational isomers were separated for the 1,2-phenylene product 14b. Other ,-hypervalent sulfur compounds 16 were synthesized under similar conditions from salts 3 and methyl cyanoacetate or dimethyl malonate. The structural assignments were discussed on the basis of IR and NMR spectroscopic data and received additional support from X-ray analysis of substrate 16a. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:95,105, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10106 [source] Experimental and modeling study of the autoignition of cyclopenteneINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 1 2008M. Yahyaoui Ignition delay times of cyclopentene,oxygen,argon mixtures were measured behind reflected shock waves. Mixtures contained 0.5% or 1% of hydrocarbons for equivalence ratios ranging from 0.5 to 1.5. Reflected shock wave conditions were as follows: temperatures from 1300 to 1700 K and pressures from 7 to 9 atm. When compared with the previous results obtained under similar conditions, it can be observed that the reactivity of cyclopentene is much lower than that of cyclohexene, but very close to that of cyclopentane. A kinetic mechanism recently proposed for the combustion of cyclopentene in a flame has been used to model these results, and a satisfactory agreement is obtained. The main reaction pathways have been derived from the flow rate, simulated temporal profiles of products, and sensitivity analyses. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 40: 25,33, 2008 [source] Cocatalysis by ruthenium(III) in hydrogen ions catalyzed oxidation of iodide ions: A kinetic studyINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 10 2004Praveen K. Tandon RuCl3 further catalyzes the oxidation of iodide ion by K3Fe(CN)6, already catalyzed by hydrogen ions. The rate of reaction, when catalyzed only by hydrogen ions, was separated graphically from the rate when both Ru(III) and H+ ions catalyzed the reaction. Reactions studied separately in the presence as well as absence of RuCl3 under similar conditions were found to follow second-order kinetics with respect to [I,], while the rate showed direct proportionality with respect to [Fe(CN)6]3,, [RuCl3], and [H+]. External addition of [Fe(CN)6]4, ions retards the reaction velocity, while changing the ionic strength of the medium has no effect on the rate. With the help of the intercept of the catalyst graph, the extent of the reaction that takes place without adding Ru(III) was calculated and it was in accordance with the values obtained from the reaction in which only H+ ions catalyzed the reaction. It is proposed that ruthenium forms a complex, which slowly disproportionates into the rate-determining step. Arrhenius parameters at four different temperatures were also calculated. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 545,553, 2004 [source] Quantification of red blood cell fragmentation by the automated hematology analyzer XE-2100 in patients with living donor liver transplantationINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 5 2005S. BANNO Summary The fragmented red cell (FRC) is a useful index for diagnosing and determining the severity of thrombotic thrombocytopenic purpura (TTP), thrombotic microangiopathy (TMA) and other similar conditions, as it is found in peripheral blood in patients with these diseases. The FRC expression rate has conventionally been determined by manual methods using smear samples. However, it is difficult to attain accurate quantification by such methods as they are time consuming and prone to a great margin of error. With cases of living donor liver transplantation, the current study examined the possibility of using a multi-parameter automated hematology analyzer, the XE-2100 (Sysmex Corporation) for FRC quantification. While there was a notable correlation between the manual and automated measurements, the manual measurement resulted in higher values. This suggested remarkable variations in judgment by individuals. The FRC values had a significant correlation with the reticulocyte count, red blood cell distribution width (RDW), fibrin/fibrinogen degradation products (P-FDP) and lactate dehydrogenase (LDH) among the test parameters, and this finding was consistent with the clinical progression in patients. The automated method can offer precise measurements in a short time without inter-observer differences, meeting the requirement for standardization. The determination of FRC count (%) by the XE-2100 that enables early diagnoses and monitoring of TTP or TMA will be useful in the clinical field. [source] Ring Expansion versus Cyclization in 4-Oxoazetidine-2- carbaldehydes Catalyzed by Molecular Iodine: Experimental and Theoretical Study in ConcertADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2010Benito Alcaide Abstract Molecular iodine (10,mol%) efficiently catalyzes the ring expansion of 4-oxoazetidine-2-carbaldehydes in the presence of tert -butyldimethylsilyl cyanide, or allylic and propargylic trimethylsilanes to afford protected 5-functionalized-3,4-dihydroxypyrrolidin-2-ones with good yield and high diastereoselectivity, through a C3C4 bond cleavage of the ,-lactam nucleus. Interestingly, in contrast to the iodine-catalyzed reactions of 3-alkoxy-,-lactam aldehydes which lead to the corresponding ,-lactam derivatives (rearrangement adducts), the reactions of 3-aryloxy-,-lactam aldehydes under similar conditions gave ,-lactam-fused chromanes (cyclization adducts) as the sole products, through exclusive electrophilic aromatic substitution involving the C3 aromatic ring and the carbaldehyde. In order to support the mechanistic proposals, theoretical studies have been performed. [source] Metalloporphyrin/Iodine(III)-Cocatalyzed Oxygenation of Aromatic HydrocarbonsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2010Akira Yoshimura Abstract Hypervalent iodine species have a pronounced catalytic effect on the metalloporphyrin-mediated oxygenations of aromatic hydrocarbons. In particular, the oxidation of anthracene to anthraquinone with Oxone readily occurs at room temperature in aqueous acetonitrile in the presence of 5,20,mol% of iodobenzene and 5,mol% of a water-soluble iron(III)-porphyrin complex. 2- tert -Butylanthracene and phenanthrene also can be oxygenated under similar conditions in the presence of 50,mol% of iodobenzene. The oxidation of styrene in the presence of 20,mol% of iodobenzene leads to a mixture of products of epoxidation and cleavage of the double bond. Partially hydrogenated aromatic hydrocarbons (e.g., 9,10-dihydroanthracene, 1,2,3,4-tetrahydronaphthalene, and 2,3-dihydro-1H -indene) afford under these conditions products of oxidation at the benzylic position in moderate yields. The proposed mechanism for these catalytic oxidations includes two catalytic redox cycles: 1) initial oxidation of iodobenzene with Oxone producing the hydroxy(phenyl)iodonium ion and hydrated iodosylbenzene, and 2) the oxidation of iron(III)-porphyrin to the oxoiron(IV)-porphyrin cation-radical complex by the intermediate iodine(III) species. The oxoiron(IV)-porphyrin cation-radical complex acts as the actual oxygenating agent toward aromatic hydrocarbons. [source] RNA damage and surveillance under oxidative stressIUBMB LIFE, Issue 10 2006Zhongwei Li Abstract RNA damage has been recently reported to increase under oxidative stress and in patients with many degenerative diseases, which has drawn attention to the consequences of RNA oxidation at the molecular and cellular levels. Under similar conditions the levels of oxidative damage in RNA are usually higher than those in DNA, which may impair protein synthesis or other RNA function. Therefore, accumulation of RNA damage must be prevented and cells have developed specific mechanisms to remove oxidatively-damaged RNA and to block incorporation of oxidized nucleotides during RNA synthesis. Removal of oxidized RNA may be mediated by specific proteins that recognize oxidative lesions and direct the RNA degradation machinery to eliminate the damaged RNAs. During RNA synthesis, oxidized ribonucleotides are hydrolyzed or discriminated from normal ribonucleotides during transcription, preventing their incorporation into RNA. Collective evidence suggests that RNA oxidative damage is a challenging and persistent problem normally controlled through RNA surveillance mechanisms, making them critical to maintaining cellular health and preventing disease. iubmb Life, 58: 581-588, 2006 [source] Difference between the spore sizes of Bacillus anthracis and other Bacillus speciesJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2007M. Carrera Abstract Aims:, To determine the size distribution of the spores of Bacillus anthracis, and compare its size with other Bacillus species grown and sporulated under similar conditions. Methods and Results:, Spores from several Bacillus species, including seven strains of B. anthracis and six close neighbours, were prepared and studied using identical media, protocols and instruments. Here, we report the spore length and diameter distributions, as determined by transmission electron microscopy (TEM). We calculated the aspect ratio and volume of each spore. All the studied strains of B. anthracis had similar diameter (mean range between 0·81 ± 0·08 ,m and 0·86 ± 0·08 ,m). The mean lengths of the spores from different B. anthracis strains fell into two significantly different groups: one with mean spore lengths 1·26 ± 0·13 ,m or shorter, and another group of strains with mean spore lengths between 1·49 and 1·67 ,m. The strains of B. anthracis that were significantly shorter also sporulated with higher yield at relatively lower temperature. The grouping of B. anthracis strains by size and sporulation temperature did not correlate with their respective virulence. Conclusions:, The spores of Bacillus subtilis and Bacillus atrophaeus (previously named Bacillus globigii), two commonly used simulants of B. anthracis, were considerably smaller in length, diameter and volume than all the B. anthracis spores studied. Although rarely used as simulants, the spores of Bacillus cereus and Bacillus thuringiensis had dimensions similar to those of B. anthracis. Significance and Impact of the Study:, Spores of nonvirulent Bacillus species are often used as simulants in the development and testing of countermeasures for biodefence against B. anthracis. The data presented here should help in the selection of simulants that better resemble the properties of B. anthracis, and thus, more accurately represent the performance of collectors, detectors and other countermeasures against this threat agent. [source] Stability of , -carotene in spray dried preparation of Rhodotorula glutinis mutant 32JOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2003P. Bhosale Abstract Aims: To obtain , -carotene-rich dry cell preparation from mutant 32 of Rhodotorula glutinis and determination of its pigment stability. Methods and Results: The mutant 32 of R. glutinis was grown in a 14 l stirred tank fermenter. Cell mass was concentrated 10-fold by cross-flow microfiltration and then spray dried. Butylated hydroxy toluene (BHT) and d -tocopherol were used as protecting agents. A two-level, three-variable, factorial optimization was performed to achieve moisture-free, non-viable and , -carotene-rich feed additive. Conclusions: The , -carotene and cell mass in stirred tank fermenter were found to be 54 ± 5 mg l,1 and 12·8 ± 2 g l,1, respectively. In the presence of BHT, 97 ± 3% (w/w) , -carotene was recovered for all the inlet temperatures studied. The best , -carotene and yeast powder recoveries were obtained at 160°C, 11·6% (w/v) cell mass concentration and 1 g l,1 BHT. The pigments inside dried yeast powder were stable in dark and cold condition for at least 10 weeks. The purified , -carotene got almost totally denatured, under similar conditions of storage, within 76 h. Significance and Impact of the Study: Spray dried and stable preparation of , -carotene-rich yeast, R. glutinis can provide alternative source of , -carotene for use in animal nutrition. [source] Comparative study of the hydrolytic degradation of glycolide/L -lactide/,-caprolactone terpolymers initiated by zirconium(IV) acetylacetonate or stannous octoateJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2008Janusz Kasperczyk Abstract A series of copolymers have been synthesized by the ring-opening polymerization of glycolide, L -lactide, and ,-caprolactone with zirconium(IV) acetylacetonate [Zr(Acac)4] or stannous octoate [Sn(Oct)2] as the catalyst. The resulting terpolymers have been characterized by analytical techniques such as proton nuclear magnetic resonance, size exclusion chromatography, and differential scanning calorimetry. Data have confirmed that Sn(Oct)2 leads to less transesterification of polymer chains than Zr(Acac)4 under similar conditions. The various copolymers have been compression-molded and allowed to degrade in a pH 7.4 phosphate buffer at 37°C. The results show that the degradation rate depends not only on the copolymer composition but also on the chain microstructure, the Sn(Oct)2 -initiated copolymers degrading less rapidly than Zr(Acac)4 -initiated ones with more random chain structures. The caproyl component appears the most resistant to degradation as its content increases in almost all cases. Moreover, caproyl units exhibit a protecting effect on neighboring lactyl or glycolyl units. The glycolyl content exhibits different features: it decreases because of faster degradation of glycolyl units, which are more hydrophilic than caproyl and lactyl ones, remains stable in the case of abundant CGC sequences, which are very resistant to degradation, or even increases because of the formation of polyglycolide crystallites. Terpolymers can crystallize during degradation if the block length of one of the components is sufficiently long, even though they are amorphous initially. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Absorption, disposition and metabolism of di-isononyl phthalate (DINP) in F-344 ratsJOURNAL OF APPLIED TOXICOLOGY, Issue 5 2002R. H. McKee Abstract Di-isononyl phthalate (DINP; CAS no. 68515-48-0) is a general-purpose plasticizer for polyvinyl chloride. It produced liver and kidney effects when given to rodents at high oral doses, but there were no target organ effects in primates treated under similar conditions. To assist in understanding the basis for these species differences, the pharmacokinetic properties of DINP were evaluated in rodents following both oral and dermal administration. These studies demonstrated that the pharmacokinetic properties of DINP are similar to those of other high-molecular-weight phthalates. When orally administered to rodents, DINP is rapidly metabolized in the gastrointestinal tract to the corresponding monoester, absorbed and excreted, primarily in the urine. Shortly after administration, DINP is found primarily in liver and kidneys, but it does not persist or accumulate in any organ or tissue. It is very poorly absorbed from the skin, but once absorbed it behaves in the same way as the orally administered material. The results of these rodent studies contrast with data from studies involving humans or other primates, which indicate low absorption at low oral doses and much more limited total absorption at high doses. It appears that many, if not all, of the effects of DINP in rodent studies are associated with internal doses that would be difficult, if not impossible, to achieve in humans under any circumstances. Thus, the results of rodent studies may not be very useful in assessing the potential risks to humans from high-molecular-weight phthalates. Copyright © 2002 John Wiley & Sons, Ltd. [source] Identification of Novel Regulators Associated With Early-Phase Osteoblast Differentiation,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 6 2004Diana S de Jong Abstract Key regulatory components of the BMP-induced osteoblast differentiation cascade remain to be established. Microarray and subsequent expression analyses in mice identified two transcription factors, Hey1 and Tcf7, with in vitro and in vivo expression characteristics very similar to Cbfa1. Transfection studies suggest that Tcf7 modulates BMP2-induced osteoblast differentiation. This study contributes to a better definition of the onset of BMP-induced osteoblast differentiation. Introduction: Elucidation of the genetic cascade guiding mesenchymal stem cells to become osteoblasts is of extreme importance for improving the treatment of bone-related diseases such as osteoporosis. The aim of this study was to identify regulators of the early phases of bone morphogenetic protein (BMP)2-induced osteoblast differentiation. Materials and Methods: Osteoblast differentiation of mouse C2C12 cells was induced by treatment with BMP2, and regulation of gene expression was studied during the subsequent 24 h using high-density microarrays. The regulated genes were grouped by means of model-based clustering, and protein functions were assigned. Real-time quantitative RT-PCR analysis was used to validate BMP2-induced gene expression patterns in C2C12 cells. Osteoblast specificity was studied by comparing these expression patterns with those in C3H10T1/2 and NIH3T3 cells under similar conditions. In situ hybridization of mRNA in embryos at embryonic day (E)14.5 and E16.5 of gestation and on newborn mouse tails were used to study in vivo expression patterns. Cells constitutively expressing the regulated gene Tcf7 were used to investigate its influence on BMP-induced osteoblast differentiation. Results and Conclusions: A total of 184 genes and expressed sequence tags (ESTs) were differentially expressed in the first 24 h after BMP2 treatment and grouped in subsets of immediate early, intermediate early, and late early response genes. Signal transduction regulatory factors mainly represented the subset of immediate early genes. Regulation of expression of these genes was direct, independent of de novo protein synthesis and independent of the cell type studied. The intermediate early and late early genes consisted primarily of genes related to processes that modulate morphology, basement membrane formation, and synthesis of extracellular calcified matrix. The late early genes require de novo protein synthesis and show osteoblast specificity. In vivo and in vitro experiments showed that the transcription factors Hey1 and Tcf7 exhibited expression characteristics and cell type specificity very similar to those of the osteoblast specific transcription factor Cbfa1, and constitutive expression of Tcf7 in C2C12 cells differentially regulated osteoblast differentiation marker genes. [source] Wet chemical synthesis of low bulk density aluminium hydroxide powderJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2003JK Pradhan Abstract Fine, low bulk density aluminium hydroxide powdered gel was prepared by the mild base hydrolysis of an aqueous solution of aluminium sulfate with hydrazine hydrate. Parameters such as method of addition of reactant, initial concentration of Al3+, mole ratio, final pH and hydrolysis temperature have a profound effect on the lightness and particle size of the powder. Optimized conditions showed that the final pH, Al3+ concentration and method of addition of reactant have a major contribution on the formation of lighter grade powder. Experiments conducted using other bases also produced lighter particles under similar conditions. Deviation from the optimized conditions led to formation of a higher bulk density product. Copyright © 2003 Society of Chemical Industry [source] THE EFFECT of MODIFIED ATMOSPHERE PACKAGING ON the MICROBIAL ECOLOGY IN REQUEIJÃO, A PORTUGUESE WHEY CHEESEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2000MANUELA E. PINTADO The effects of modified atmosphere packaging on growth of adventitious microorganisms in Portuguese whey cheese (Requeijão) were studied following a response surface methodology using storage time (2, 6, 10 and 15 days), storage temperature (4, 12 and 18C) and fraction of CO2 in the overhead gaseous mixture also containing nitrogen (0, 50 and 100%) as manipulated variables. the viable numbers of Enterobacteriacea, staphylococci, yeasts and spore-forming bacteria in the experimental whey cheeses did not increase within 15 days when storage was at 4C under 100% CO2; those of enterococci increased significantly after 6 days under similar conditions, and a similar inhibiting effect was observed against Bacillus, pseudomonads, lactobacilli and streptococci. It was observed that 100% N2 at 4C was able to completely inhibit growth of staphylococci, lactobacilli and Bacillus for 2 days. the loci (and the nature) of the optima in terms of manipulated variables were obtained for all microbial groups studied. No true overall minimum was found, but storage conditions preset at 4C and 100% CO2 led to a 15 day extension of the shelf-life of Requeijão. [source] Convenient substitution of hydroxypyridines with trifluoroacetaldehyde ethyl hemiacetalJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2001Yuefa Gong Thermal substitution of 4-hydroxypyridine 1 with trifluoroacetaldehyde ethyl hemiacetal (TFAE) leads to a moderate yield of 3-(1-hydroxy-2,2,2-trifluoroethyl)-4-hydroxypyridine 7 in the presence of a catalytic amount of anhydrous potassium carbonate. Under similar conditions, several ,-trifluoromethyl hydroxy-pyridinemethanols 8,15 are easily prepared from 2- or 3-hydroxypyridines 2,6. [source] Effect of metal-support interface on hydrogen permeation through palladium membranesAICHE JOURNAL, Issue 3 2009Ke Zhang Abstract Thin palladium membranes of different thicknesses were prepared on sol-gel derived mesoporous ,-alumina/,-alumina and yttria-stabilized zirconia/,-alumina supports by a method combining sputter deposition and electroless plating. The effect of metal-support interface on hydrogen transport permeation properties was investigated by comparing hydrogen permeation data for these membranes measured under different conditions. Hydrogen permeation fluxes for the Pd/,-Al2O3/,-Al2O3 membranes are significantly smaller than those for the Pd/YSZ/,-Al2O3 membranes under similar conditions. As the palladium membrane thickness increases, the difference in permeation fluxes between these two groups of membranes decreases and the pressure exponent for permeation flux approaches 0.5 from 1. Analysis of the permeation data with a permeation model shows that both groups of membranes have similar hydrogen permeability for bulk diffusion, but the Pd/,-Al2O3/,-Al2O3 membranes exhibit a much lower surface reaction rate constant with higher activation energy, due possibly to the formation of Pd-Al alloy, than the Pd/YSZ/,-Al2O3 membranes. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Oxidative coupling of methane in dense ceramic membrane reactor with high yieldsAICHE JOURNAL, Issue 10 2002F. T. Akin Oxidative coupling of methane (OCM) was studied with dense tubular Bi1.5Y0.3Sm0.2O3 (BYS) membranes at various temperatures (870,930°C). BYS powders were synthesized by a citrate method. Tubular-shaped dense membranes of BYS in the fluorite-type FCC phase structure were fabricated by cold isostatic pressing with green machining. The best one-pass C2 (C2H4 + C2H6) yield achieved for OCM in the BYS dead-end membrane reactor was 35% at a C2 selectivity of 54% at 900°C. At the same C2 yield, the membrane reactor mode gives C2 selectivity of over 200% higher than the cofeed mode in the same membrane reactor under similar conditions. The oxygen permeation fluxes through tubular BYS membrane reactors under OCM reaction conditions are approximately 1.5 to 3.5 times higher than those under oxygen permeation conditions with He as the purge. After 6 days of OCM, BYS membrane remained in good integrity with minor phase segregation observed at the reaction side of the membrane. [source] | |||||||||||||||||||||||||||||||||||||||||||