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Glypican-3 reexpression regulates apoptosis in murine adenocarcinoma mammary cells modulating PI3K/Akt and p38MAPK signaling pathways

BUCHANAN, C.; STIGLIANO, I.; GARAY-MALPARTIDA, H. M.; GOMES, L. Rodrigues; PURICELLI, L.; SOGAYAR, M. C.; JOFFE, E. Bal de Kier; PETERS, M. G.
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
75.39%
Glypican-3 (GPC3) is a proteoglycan involved in proliferation and cell survival. Several reports demonstrated that GPC3 is downregulated in some tumors, such as breast cancer. Previously, we determined that GPC3 reexpression in the murine mammary adenocarcinoma LM3 cells induced an impairment of their invasive and metastatic capacities, associated with a decrease of their motility and an increase of their cell death. We demonstrated that GPC3 inhibits canonical Wnt signaling, as well as it activates non canonical pathway. Now, we identified signaling pathways responsible for the pro-apoptotic role of GPC3 in LM3 cells. We found for the first time that GPC3 inhibits the PI3K/Akt anti-apoptotic pathway while it stimulates the p38MAPK stress-activated one. We report a concomitant modulation of CDK inhibitors as well as of pro- and anti-apoptotic molecules. Our results provide new clues regarding the mechanism involved in the modulation induced by GPC3 of mammary tumor cell growth and survival.; FONCyT[PICT 14088]; FONCyT[BID 1728/OC-AR]; FONCyT[PICT 00220]; University of Buenos Aires[UBACyT M068], Argentina

3`3-Ditrifluoromethyldiphenyl diselenide: A new organoselenium compound with interesting antigenotoxic and antimutagenic activities

MACHADO, Miriana da Silva; VILLELA, Izabel Vianna; MOURA, Dinara Jaqueline; ROSA, Renato Moreira; SALVADOR, Mirian; LOPES, Norberto P.; BRAGA, Antonio Luiz; ROESLER, Rafael; SAFFI, Jenifer; HENRIQUES, Joao Antonio P.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
65.57%
The trace element selenium (Se), once known only for its potential toxicity, is now a well-established essential micronutrient for mammals. The organoselenium compound diphenyl diselenide (DPDS) has shown interesting antioxidant and neuroprotective activities. On the other hand, this compound has also presented pro-oxidant and mutagenic effects. The compound 3`3-ditrifluoromethyldiphenyl diselenide (DFDD), a structural analog of diphenyl diselenide, has proven antipsychotic activity in mice. Nevertheless, as opposed to DPDS, little is known on the biological and toxicological properties of DFDD. In the present study, we report the genotoxic effects of the organoselenium compound DFDD on Salmonella typhimurium, Saccharomyces cerevisiae and Chinese hamster lung fibroblasts (V79 cells). DFDD protective effects against hydrogen peroxide (H(2)O(2))-induced DNA damage in vitro are demonstrated. DFDD did not cause mutagenic effects on S. typhimurium or S. cerevisiae strains; however, it induced DNA damage in V79 cells at doses higher than 25 mu M, as detected by comet assay. DFDD protected S. typhimurium and S. cerevisiae against H(2)O(2)-induced mutagenicity, and, at doses lower than 12.5 mu M, prevented H(2)O(2)-induced genotoxicity in V79 cells. The in vitro assays demonstrated that DFDD mimics catalase activity better than DPDS...

3-azetidinonas e 3-azetidinois : preparação e aplicações na sintese de azetidinas substituidas; Azetidin-3-ones and Azetidin-3-ols: preparation and applications in the synthesis of substituted Azetidines

Antonio Carlos Bender Burtoloso
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 03/03/2006 PT
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O trabalho de tese envolve a química de heterociclos de 4 membros, contendo um átomo de nitrogênio (azetidinas). Neste trabalho são apresentados 3 capítulos envolvendo 3-azetidinonas e 3-azetidinóis como principais intermediários para a síntese de azetidinas. No primeiro capítulo é demostrado o desenvolvimento de uma nova metodologia para a síntese de 3-azetidinonas 2,4-dissubstituídas quirais, a partir de aminoácidos, e suas aplicações na síntese de azetidinas totalmente substituídas. Esta metodologia consiste basicamente no emprego da química de carbenóides para a construção do heterociclo de 4 membros (inserção N-H catalisada por cobre ou ródio a partir de diazocetonas). No segundo capítulo, 3-azetidinonas mais simples (mono-substituídas) são preparadas e utilizadas como intermediários-chave na síntese de análogos dos ácidos aspártico e glutâmico, contendo um núcleo azetidínico como elemento de rigidez conformacional. No terceiro e último capítulo é discutida a reação de cicloadição [2+2] entre cetenos e enecarbamatos ou enamidas endocíclicas de 4 membros. Com o êxito observado nesta investigação o aduto de cicloadição foi convertido em um novo derivado substituído do ácido 3-azetidina carboxílico (ácido que apresenta interessantes atividades biológicas). Um outro estudo realizado foi a tentativa de preparação de um enecarbamato ou enamida endocíclica de 4 membros quiral (2-azetinas)...

Antileishmanial activity of 3-(3,4,5-trimethoxyphenyl) propanoic acid purified from Amazonian Piper tuberculatum Jacq., Piperaceae, fruits

Ferreira,Maria Goretty P. R.; Kayano,Anderson M.; Silva-Jardim,Izaltina; Silva,Tatiany O. da; Zuliani,Juliana P.; Facundo,Valdir A.; Calderon,Leonardo de A.; Almeida-e-Silva,Alexandre de; Ciancaglini,Pietro; Stábeli,Rodrigo G.
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2010 EN
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Leishmanicidal activity of the 3-(3,4,5-trimethoxyphenyl) propanoic acid (TMPP) isolated from EtOH extracts of the Amazonian Piper turbeculatum Jacq. fruits was evaluated in vitro using Leishmania amazonensis promastigotes. The TMPP was assayed at concentrations of 1600 to 6.25 µg/mL for 24, 48, 72 and 96 h. Promastigotes viability was analyzed and the IC50 of TMPP was 145 µg/mL.

Differences in Spatial Expression between 14-3-3 Isoforms in Germinating Barley Embryos1

Testerink, Christa; van der Meulen, René M.; Oppedijk, Berry J.; de Boer, Albertus H.; Heimovaara-Dijkstra, Sjoukje; Kijne, Jan W.; Wang, Mei
Fonte: American Society of Plant Physiologists Publicador: American Society of Plant Physiologists
Tipo: Artigo de Revista Científica
Publicado em /09/1999 EN
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The family of 14-3-3 proteins is ubiquitous in eukaryotes and has been shown to exert an array of functions. We were interested in the possible role of 14-3-3 proteins in seed germination. Therefore, we studied the expression of 14-3-3 mRNA and protein in barley (Hordeum distichum L.) embryos during germination. With the use of specific cDNA probes and antibodies, we could detect individual expression of three 14-3-3 isoforms, 14-3-3A, 14-3-3B, and 14-3-3C. Each homolog was found to be expressed in barley embryos. Whereas protein levels of all three isoforms were constant during germination, mRNA expression was found to be induced upon imbibition of the grains. The induction of 14-3-3A gene expression during germination was different from that of 14-3-3B and 14-3-3C. In situ immunolocalization analysis showed similar spatial expression for 14-3-3A and 14-3-3B, while 14-3-3C expression was markedly different. Whereas 14-3-3A and 14-3-3B were expressed throughout the embryo, 14-3-3C expression was tissue specific, with the strongest expression observed in the scutellum and the L2 layer of the shoot apical meristem. These results show that 14-3-3 homologs are differently regulated in barley embryos, and provide a first step in acquiring more knowledge about the role of 14-3-3 proteins in the germination process.

Regulation of Raf-1 kinase activity by the 14-3-3 family of proteins.

Li, S; Janosch, P; Tanji, M; Rosenfeld, G C; Waymire, J C; Mischak, H; Kolch, W; Sedivy, J M
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/02/1995 EN
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We have identified the beta (beta) isoform of the 14-3-3 family of proteins as an activator of the Raf-1 protein kinase. 14-3-3 was isolated in a yeast two-hybrid screen for Raf-1 kinase domain binding proteins. Purified bovine brain 14-3-3 interacted specifically with both c-Raf-1 and the isolated Raf-1 kinase domain. Association was sensitive to the activation status of Raf-1; 14-3-3 bound to unactivated Raf-1, but not Raf-1 activated by protein kinase C alpha or Ras and Lck. The significance of these interactions under physiological conditions was demonstrated by co-immunoprecipitation of Raf-1 and 14-3-3 from extracts of quiescent, but not mitogen-stimulated, NIH 3T3 cells. 14-3-3 was not a preferred Raf-1 substrate in vitro and did not significantly affect Raf-1 kinase activity in a purified system. However, in cell-free extracts 14-3-3 acted as a Ras-independent activator of both c-Raf-1 and the Raf-1 kinase domain. The same results were obtained in vivo using transfection assays; 14-3-3 enhanced both c-Raf-1- and Raf-1 kinase domain-stimulated expression of AP-1- and NF-kappa B-dependent reporter genes and accelerated Raf-1 kinase domain-triggered differentiation of PC12 cells. We conclude that 14-3-3 is a latent co-activator bound to unactivated Raf-1 in quiescent cells and mediates mitogen-triggered but Ras-independent regulatory effects aimed directly at the kinase domain.

An Obligatory Heterodimer of 14-3-3β and 14-3-3ε Is Required for Aldosterone Regulation of the Epithelial Sodium Channel*S⃞

Liang, Xiubin; Butterworth, Michael B.; Peters, Kathryn W.; Walker, William H.; Frizzell, Raymond A.
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
Publicado em 10/10/2008 EN
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Increased distal nephron sodium absorption in response to aldosterone involves Nedd4-2 phosphorylation, which blocks its ability to ubiquitylate ENaC and increases apical membrane channel density by reducing its endocytosis. Our prior work (Liang, X., Peters, K. W., Butterworth, M. B., and Frizzell, R. A. (2006) J. Biol. Chem. 281, 16323–16332) showed that aldosterone selectively increased 14-3-3 protein isoform expression and that the association of 14-3-3β with phospho-Nedd4-2 was required for sodium transport stimulation. The knockdown of 14-3-3β alone nearly eliminated the response to aldosterone, despite the expression of other 14-3-3 isoforms in cortical collecting duct (CCD) cells. To further examine this marked effect of 14-3-3β knockdown, we evaluated the hypothesis that phospho-Nedd4-2 binding prefers a heterodimer composed of two different 14-3-3 isoforms. We tested this concept in polarized CCD cells using RNA interference and assays of sodium transport and of the interaction of Nedd4-2 with 14-3-3ε, a second aldosterone-induced isoform. As observed previously for 14-3-3β knockdown, small interfering RNA-induced reduction of 14-3-3ε markedly attenuated aldosterone-stimulated ENaC expression and sodium transport and increased the interaction of Nedd4-2 with ENaC toward prealdosterone levels. After aldosterone induction...

14-3-3 Proteins Regulate Retinal Axon Growth by Modulating ADF/Cofilin Activity

Yoon, Byung C.; Zivraj, Krishna H.; Strochlic, Laure; Holt, Christine E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/2012 EN
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Precise navigation of axons to their targets is critical for establishing proper neuronal networks during development. Axon elongation, whereby axons extend far beyond the site of initiation to reach their target cells, is an essential step in this process, but the precise molecular pathways that regulate axon growth remain uncharacterized. Here we show that 14-3-3/14-3-3ς proteins—adaptor proteins that modulate diverse cellular processes including cytoskeletal dynamics—play a critical role in Xenopus retinal ganglion cell (RGC) axon elongation in vivo and in vitro. We have identified the expression of 14-3-3/14-3-3ς transcripts and proteins in retinal growth cones, with higher levels of expression occurring during the phase of rapid pathway extension. Competitive inhibition of 14-3-3/14-3-3ς by expression of a genetically encoded peptide, R18, in RGCs resulted in a marked decrease in the length of the initial retinotectal projection in vivo and a corresponding decrease in axon elongation rate in vitro (30–40%). Furthermore, 14-3-3/14-3-3ς (R1) co-localized with Xenopus actin depolymerizing factor (ADF)/cofilin (XAC) in RGC growth cones. Inhibition of 14-3-3/14-3-3ς function with either R18 or morpholinos reduced the level of inactive pXAC and increased the sensitivity to collapse by the repulsive cue...

Proteomic analysis of media from lung cancer cells reveals role of 14-3-3 proteins in cachexia

McLean, Julie B.; Moylan, Jennifer S.; Horrell, Erin M. W.; Andrade, Francisco H.
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
Publicado em 28/04/2015 EN
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Aims: At the time of diagnosis, 60% of lung cancer patients present with cachexia, a severe wasting syndrome that increases morbidity and mortality. Tumors secrete multiple factors that contribute to cachectic muscle wasting, and not all of these factors have been identified. We used Orbitrap electrospray ionization mass spectrometry to identify novel cachexia-inducing candidates in media conditioned with Lewis lung carcinoma cells (LCM). Results: One-hundred and 58 proteins were confirmed in three biological replicates. Thirty-three were identified as secreted proteins, including 14-3-3 proteins, which are highly conserved adaptor proteins known to have over 200 binding partners. We confirmed the presence of extracellular 14-3-3 proteins in LCM via western blot and discovered that LCM contained less 14-3-3 content than media conditioned with C2C12 myotubes. Using a neutralizing antibody, we depleted extracellular 14-3-3 proteins in myotube culture medium, which resulted in diminished myosin content. We identified the proposed receptor for 14-3-3 proteins, CD13, in differentiated C2C12 myotubes and found that inhibiting CD13 via Bestatin also resulted in diminished myosin content. Conclusions: Our novel findings show that extracellular 14-3-3 proteins may act as previously unidentified myokines and may signal via CD13 to help maintain muscle mass.

NMR spectroscopy of 14-3-3ζ reveals a flexible C-terminal extension: Differentiation of the chaperone and phosphoserine-binding activities of 14-3-3ζ; NMR spectroscopy of 14-3-3zeta reveals a flexible C-terminal extension: Differentiation of the chaperone and phosphoserine-binding activities of 14-3-3zeta

Williams, D.; Ecroyd, H.; Goodwin, K.; Dai, H.; Fu, H.; Woodcock, J.; Zhang, L.; Carver, J.
Fonte: Portland Press Publicador: Portland Press
Tipo: Artigo de Revista Científica
Publicado em //2011 EN
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Intracellular 14-3-3 proteins bind to many proteins, via a specific phosphoserine motif, regulating diverse cellular tasks including cell signalling and disease progression. The 14-3- 3ζ isoform is a molecular chaperone, preventing the stressinduced aggregation of target proteins in a manner comparable with that of the unrelated sHsps (small heat-shock proteins). 1H-NMR spectroscopy revealed the presence of a flexible and unstructured C-terminal extension, 12 amino acids in length, which protrudes from the domain core of 14-3-3ζ and is similar in structure and length to the C-terminal extension of mammalian sHsps. The extension stabilizes 14-3-3ζ, but has no direct role in chaperone action. Lys49 is an important functional residue within the ligand-binding groove of 14-3- 3ζ with K49E 14-3-3ζ exhibiting markedly reduced binding to phosphorylated and non-phosphorylated ligands. The R18 peptide binds to the binding groove of 14-3-3ζ with high affinity and also reduces the interaction of 14-3-3ζ ligands. However, neither the K49E mutation nor the presence of the R18 peptide affected the chaperone activity of 14-3-3ζ , implying that the C-terminal extension and binding groove of 14-3-3ζ do not mediate interaction with target proteins during chaperone action. Other region(s) in 14-3-3ζ are most likely to be involved...

Locomotor hyperactivity in 14-3-3ζ KO mice is associated with dopamine transporter dysfunction; Locomotor hyperactivity in 14-3-3Zeta KO mice is associated with dopamine transporter dysfunction

Ramshaw, H.; Xu, X.; Jaehne, E.; McCarthy, P.; Greenberg, Z.; Saleh, E.; McClure, B.; Woodcock, J.; Kabbara, S.; Wiszniak, S.; Wang, T.Y.; Parish, C.; van den Buuse, M.; Baune, B.; Lopez, A.; Schwarz, Q.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em //2013 EN
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75.53%
Dopamine (DA) neurotransmission requires a complex series of enzymatic reactions that are tightly linked to catecholamine exocytosis and receptor interactions on pre- and postsynaptic neurons. Regulation of dopaminergic signalling is primarily achieved through reuptake of extracellular DA by the DA transporter (DAT) on presynaptic neurons. Aberrant regulation of DA signalling, and in particular hyperactivation, has been proposed as a key insult in the presentation of schizophrenia and related neuropsychiatric disorders. We recently identified 14-3-3ζ as an essential component of neurodevelopment and a central risk factor in the schizophrenia protein interaction network. Our analysis of 14-3-3ζ-deficient mice now shows that baseline hyperactivity of knockout (KO) mice is rescued by the antipsychotic drug clozapine. 14-3-3ζ KO mice displayed enhanced locomotor hyperactivity induced by the DA releaser amphetamine. Consistent with 14-3-3ζ having a role in DA signalling, we found increased levels of DA in the striatum of 14-3-3ζ KO mice. Although 14-3-3ζ is proposed to modulate activity of the rate-limiting DA biosynthesis enzyme, tyrosine hydroxylase (TH), we were unable to identify any differences in total TH levels, TH localization or TH activation in 14-3-3ζ KO mice. Rather...

14-3-3ε and ζ regulate neurogenesis and differentiation of neuronal progenitor cells in the developing brain; 14-3-3epsilon and zeta regulate neurogenesis and differentiation of neuronal progenitor cells in the developing brain

Toyo-oka, K.; Wachi, T.; Hunt, R.F.; Baraban, S.C.; Taya, S.; Ramshaw, H.; Kaibuchi, K.; Schwarz, Q.P.; Lopez, A.F.; Wynshaw-Boris, A.
Fonte: Society for Neuroscience Publicador: Society for Neuroscience
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
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125.46%
During brain development, neural progenitor cells proliferate and differentiate into neural precursors. These neural precursors migrate along the radial glial processes and localize at their final destination in the cortex. Numerous reports have revealed that 14-3-3 proteins are involved in many neuronal activities, although their functions in neurogenesis remain unclear. Here, using 14-3-3ε/ζ double knock-out mice, we found that 14-3-3 proteins are important for proliferation and differentiation of neural progenitor cells in the cortex, resulting in neuronal migration defects and seizures. 14-3-3 deficiency resulted in the increase of δ-catenin and the decrease of β-catenin and αN-catenin. 14-3-3 proteins regulated neuronal differentiation into neurons via direct interactions with phosphorylated δ-catenin to promote F-actin formation through a catenin/Rho GTPase/Limk1/cofilin signaling pathway. Conversely, neuronal migration defects seen in the double knock-out mice were restored by phosphomimic Ndel1 mutants, but not δ-catenin. Our findings provide new evidence that 14-3-3 proteins play important roles in neurogenesis and neuronal migration via the regulation of distinct signaling cascades.; Kazuhito Toyo-oka, Tomoka Wachi...

Modélisation toxicocinétique du benzo(a)pyrène et 3-hydroxybenzo(a)pyrène pour l’interprétation des données de surveillance biologique de l’exposition chez les travailleurs

Heredia Ortiz, Roberto
Fonte: Université de Montréal Publicador: Université de Montréal
Tipo: Thèse ou Mémoire numérique / Electronic Thesis or Dissertation
FR
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65.64%
De nombreux travailleurs sont exposés aux hydrocarbures aromatiques polycycliques (HAP). Le benzo(a)pyrène (BaP) fait partie de ce groupe de polluants. Cette substance a été classée cancérogène reconnu chez l’humain. Pour évaluer l'exposition aux HAP cancérogènes, plusieurs chercheurs ont proposé d’utiliser la mesure du 3-hydroxybenzo(a)pyrène (3-OHBaP) dans l’urine des travailleurs exposés. Dans le cadre du présent projet, deux approches de modélisation ont été développées et appliquées pour permettre une meilleure compréhension de la toxicocinétique du BaP et son biomarqueur d’intérêt actuel, le 3-OHBaP, et pour aider à interpréter les résultats de surveillance biologique. Un modèle toxicocinétique à plusieurs compartiments a été développé sur la base des données préalablement obtenues sur le rat par notre groupe. Selon le modèle, le BaP injecté par voie intraveineuse est rapidement distribué du sang vers les tissus (t½ ≈ 4 h), avec une affinité particulière pour les poumons et les composantes lipidiques des tissus. Le BaP est ensuite distribué vers la peau et le foie. Au foie, le BaP est promptement métabolisé et le 3-OHBaP est formé avec une demi-vie de ≈ 3 h. Le métabolisme pulmonaire du BaP a également été pris en compte...

Cell cycle roles for two 14-3-3 proteins during Drosophila development

Su, Tin Tin; Parry, Devin H.; Donahoe, Bryon; Chien, Cheng-Ting; O'Farrell, Patrick H.; Purdy, Amanda
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/2001 EN
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75.53%
Drosophila 14-3-3ε and 14-3-3ζ proteins have been shown to function in RAS/MAP kinase pathways that influence the differentiation of the adult eye and the embryo. Because 14-3-3 proteins have a conserved involvement in cell cycle checkpoints in other systems, we asked (1) whether Drosophila 14-3-3 proteins also function in cell cycle regulation, and (2) whether cell proliferation during Drosophila development has different requirements for the two 14-3-3 proteins. We find that antibody staining for 14-3-3 family members is cytoplasmic in interphase and perichromosomal in mitosis. Using mutants of cyclins, Cdk1 and Cdc25string to manipulate Cdk1 activity, we found that the localization of 14-3-3 proteins is coupled to Cdk1 activity and cell cycle stage. Relocalization of 14-3-3 proteins with cell cycle progression suggested cell-cycle-specific roles. This notion is confirmed by the phenotypes of 14-3-3ε and 14-3-3ζ mutants: 14-3-3ε is required to time mitosis in undisturbed post-blastoderm cell cycles and to delay mitosis following irradiation; 14-3-3ζ is required for normal chromosome separation during syncytial mitoses. We suggest a model in which 14-3-3 proteins act in the undisturbed cell cycle to set a threshold for entry into mitosis by suppressing Cdk1 activity...

Hyperovals of $H(3,q^2)$ when $q$ is even

Cossidente, Antonio; King, Oliver H.; Marino, Giuseppe
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/11/2012
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For even $q$, a group $G$ isomorphic to $PSL(2,q)$ stabilizes a Baer conic inside a symplectic subquadrangle ${\cal W}(3,q)$ of ${\cal H}(3,q^2)$. In this paper the action of $G$ on points and lines of ${\cal H}(3,q^2)$ is investigated. A construction is given of an infinite family of hyperovals of size $2(q^3-q)$ of ${\cal H}(3,q^2)$, with each hyperoval having the property that its automorphism group contains $G$. Finally it is shown that the hyperovals constructed are not isomorphic to known hyperovals.; Comment: Submitted

An observational investigation of the identity of B11244 ($l$-C$_3$H$^+$/C$_3$H$^-$)

McGuire, Brett A.; Carroll, P. Brandon; Gratier, Pierre; Guzmán, Viviana; Pety, Jerome; Roueff, Evelyne; Gerin, Maryvonne; Blake, Geoffrey A.; Remijan, Anthony J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/11/2013
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65.61%
Pety et al. (2012) have reported the detection of eight transitions of a closed-shell, linear molecule (B11244) in observations toward the Horsehead PDR, which they attribute to the $l$-C$_3$H$^+$ cation. Recent high-level \textit{ab initio} calculations have called this assignment into question; the anionic C$_3$H$^-$ molecule has been suggested as a more likely candidate. Here, we examine observations of the Horsehead PDR, Sgr B2(N), TMC-1, and IRC+10216 in the context of both $l$-C$_3$H$^+$ and C$_3$H$^-$. We find no observational evidence of $K_a = 1$ lines which should be present were the carrier indeed C$_3$H$^-$. Additionally, we find a strong anti-correlation between the presence of known molecular anions and B11244 in these regions. Finally, we discuss the formation and destruction chemistry of C$_3$H$^-$ in the context of the physical conditions in the regions. Based on these results, we conclude there is little evidence to support the carrier is C$_3$H$^-$.; Comment: 17 pages, 3 figures, accepted in the Astrophysical Journal

Investigating the Cosmic-ray Ionization Rate Near the Supernova Remnant IC 443 through H^(+)_(3) Observations

Indriolo, Nick; Blake, Geoffrey A.; Goto, Miwa; Usuda, Tomonori; Oka, Takeshi; Geballe, T. R.; Fields, Brian D.; McCall, Benjamin J.
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 01/12/2010
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Observational and theoretical evidence suggests that high-energy Galactic cosmic rays are primarily accelerated by supernova remnants. If also true for low-energy cosmic rays, the ionization rate near a supernova remnant should be higher than in the general Galactic interstellar medium (ISM). We have searched for H^(+)_(3) absorption features in six sight lines which pass through molecular material near IC 443—a well-studied case of a supernova remnant interacting with its surrounding molecular material—for the purpose of inferring the cosmic-ray ionization rate in the region. In two of the sight lines (toward ALS 8828 and HD 254577) we find large H^(+)_(3) column densities, N(H^(+)_(3)) ≈ 3 × 10^(14) cm^(–2), and deduce ionization rates of ζ2 ≈ 2 × 10^(–15) s^(–1), about five times larger than inferred toward average diffuse molecular cloud sight lines. However, the 3σ upper limits found for the other four sight lines are consistent with typical Galactic values. This wide range of ionization rates is likely the result of particle acceleration and propagation effects, which predict that the cosmic-ray spectrum and thus ionization rate should vary in and around the remnant. While we cannot determine if the H^(+)_(3) absorption arises in post-shock (interior) or pre-shock (exterior) gas...

Chemistry of C_3 and carbon chain molecules in DR21(OH)

Mookerjea, B.; Hassel, G. E.; Gerin, M.; Giesen, T.; Herbst, E.; Black, J. H.; Goldsmith, P. F.; Menten, K. M.; Krełowski, J.; De Luca, M.; Csengeri, T.; Joblin, C.; Kaźmierczak, M.; Schmidt, M.; Goicoechea, J. R.; Cernicharo, J.; Stutzki, J.
Fonte: EDP Sciences Publicador: EDP Sciences
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em /10/2012
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65.59%
Context. C_3 is the smallest pure carbon chain detected in the dense environment of star-forming regions, although diatomic C_2 is detected in diffuse clouds. Measurement of the abundance of C_3 and the chemistry of its formation in dense star-forming regions has remained relatively unexplored. Aims. We aim to identify the primary C_3 formation routes in dense star-forming regions following a chemical network producing species like CCH and c-C_(3)H_2 in the star-forming cores associated with DR21(OH), a high-mass star-forming region. Methods. We observed velocity resolved spectra of four ro-vibrational far-infrared transitions of C3 between the vibrational ground state and the low-energy ν_2 bending mode at frequencies between 1654–1897 GHz using HIFI on board Herschel, in DR21(OH). Several transitions of CCH and c-C_(3)H_2 were also observed with HIFI and the IRAM 30 m telescope. Rotational temperatures and column densities for all chemical species were estimated. A gas and grain warm-up model was used to obtain estimates of densities and temperatures of the envelope. The chemical network in the model was used to identify the primary C_3 forming reactions in DR21(OH). Results. We detected C_3 in absorption in four far-infrared transitions...

3-[211At]astato-4-fluorobenzylguanidine: a potential therapeutic agent with prolonged retention by neuroblastoma cells.

Vaidyanathan, G; Zhao, XG; Larsen, RH; Zalutsky, MR
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Artigo de Revista Científica Formato: 226 - 233
Publicado em //1997 ENG
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An analogue of meta-iodobenzylguanidine (MIBG) in which an aromatic hydrogen was replaced with fluorine has been found to possess many properties similar to those of the parent compound. Moreover, 4-fluoro-3-iodobenzylguanidine (FIBG) was retained in vitro by human neuroblastoma cells to a much greater extent than MIBG itself. Since alpha-emitters such as 211At could be valuable for the treatment of micrometastatic disease, an FIBG analogue in which the iodine atom is replaced by 211At would be of interest. In this study, we have evaluated the in vitro and in vivo properties of 3-[211At]astato-4-fluorobenzylguanidine ([211At]AFBG). The specific binding of [211At]AFBG to SK-N-SH human neuroblastoma cells remained fairly constant over 2- to 3-log activity range and was similar to that of [131I]MIBG. The uptake of [211At]AFBG by this cell line was reduced by desipramine, ouabain, 4 degrees C incubation, noradrenaline, unlabelled MIBG and FIBG, suggesting that its uptake is specifically mediated through an active uptake-1 mechanism. Over the 16 h period studied, the amount of [211At]AFBG retained was similar to that of [131I]FIBG, whereas the per cent of retained meta-[211At]astatobenzylguanidine ([211At]MABG) was considerably less than that of [131I]FIBG (53% vs 75%; P < 0.05). The IC50 values for the inhibition of uptake of [131I]MIBG...

Evaluation of hβD-1 and hβD-2 levels in saliva of patients with oral mucosal diseases

Kucukkolbasi,H; Kucukkolbasi,S; Ayyildiz,HF; Dursun,R; Kara,H
Fonte: West Indian Medical Journal Publicador: West Indian Medical Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2013 EN
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OBJECTIVE: This study aimed to determine a possible correlation between oral mucosal disease and salivary concentrations of the antimicrobial peptides human beta-defensin-1 (hβD-1) and human betadefensin- 2 (hβD-2). METHOD: The present work focussed on the establishment of a reversed phase-high performance liquid chromatography (RP-HPLC) procedure to quantify human beta-defensins (hβD-1 and hβD-2) in saliva samples of patients with oral diseases such as lichen planus (n = 10), Behçet (n = 10) and recurrent apthous stomatitis (n = 10). RESULTS: Linear calibration range for hβD-1 and hβD-2 defensins was 1.67−200 µg mL-1 and 3.13− 100 µg mL-1 with R2 values of 0.9998 and 0.996, correspondingly. The concentration of beta-defensins in saliva was determined by comparing the peak areas of eluted hβD-1 and hβD-2 with that of their standards. The variation of the amount of beta-defensins was evaluated by comparisons of the results obtained from the patients with oral mucosal diseases before and after treatments and the control subjects. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 1.62 µg mL- 1 and 5.39 µg mL-1 for hβD-1 and 0.94 µg mL-1 and 3.13 µg mL-1 for hβD-2...