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  • Publication
    1, 2, 4-Triazole as a reference material for combustion calorimetry of N-containing compounds
    ( 2001-01-01)
    Roux M.
    ;
    Torres L.
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    DAVALOS PRADO, JUAN ZENON
    A micro-bomb combustion calorimeter recently designed for samples of mass ≈80 mg has been improved and tested with m-methoxybenzoic acid in order to verify the chemistry of the combustion process and the accuracy of the energy corrections involved in the analysis of results. From measurements in this calorimeter, the standard massic energy of combustion of 1, 2, 4-triazole was determined to be Δcuo = -(19200.3 ± 3.4) J·g−1. Some new measurements with our macro combustion calorimeter confirm an earlier result from this laboratory of -(19203.1 ± 1.2) J·g−1. Determination of the purity by d.s.c. of 1, 2, 4-triazole purified some 10 years ago reveals that samples of this compound remained unchanged and suggest that 1, 2, 4-triazole be used as a possible reference material for organic compounds with a high content of nitrogen. From the experimental results with the micro-bomb combustion calorimeter, the actual and earlier results from macro-bomb combustion calorimetry, and those obtained in other laboratories, the standard massic energy of combustion of 1, 2, 4-triazole was deduced to be Δcuo = -(19202.5 ± 1.7) J·g−1. © 2000 Academic Press.
  • Publication
    1,1′‐Disubstituted Ferrocene‐Containing Thermotropic Liquid Crystals of structure [Fe{(η5‐C5H4)COOC6H4OCnH2n+1}2] (X OOC or COO). Influence of the orientation of the central ester function on the mesogenic properties
    ( 1993-01-01)
    Deschenaux R.
    ;
    Marendaz J.‐.
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    SANTIAGO CONTRERAS, JULIO CESAR
    The two series I and II of 1,1′ ‐disubstituted ferrocenes which differ by the direction of the ester function included in the rigid organic part were synthesized and their liquid crystal properties examined. These latter were found to be strongly dependent on the orientation of the connecting ester group and on the alkyl chain length. Copyright © 1993 Verlag GmbH & Co. KGaA, Weinheim
  • Publication
    1,3-Diethyl-2-thiobarbituric acid as an alternative coinitiator for acidic photopolymerizable dental materials
    (Wiley-Blackwell, 2013-10-01)
    Münchow E.
    ;
    Valente L.
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    LUQUE PERALTA, SONIA
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    Fernández M.
    ;
    Lima G.
    ;
    Petzhold C.
    ;
    Piva E.
    ;
    Ogliari F.
    The ethyl-4-dimethylaminobenzoate (EDAB) is widely used as a coinitiator of the camphorquinone (CQ), but in acidic circumstances it might present some instability, reducing the polymerization efficiency of the material. Considering this, new coinitiators are being evaluated. Hence, this study evaluated the kinetic of polymerization (KP), the degree of conversion (DC), and the rate of polymerization (RP) of experimental resin adhesives containing 1,3-diethyl-2-thiobarbituric acid (TBA) as a coinitiator of the CQ. The experimental monomeric blend was prepared with bisphenol A glycidyl dimethacrylate, 2-hydroxyethyl methacrylate, and acidic monomers. CQ was added at 1 mol % as photoinitiator. Six groups were formulated: four containing concentrations of 0.1, 0.5, 1, and 2 mol % of TBA, one without coinitiator, and the last one containing 1 mol % of EDAB (control group). The KP and the R P were performed using real-time Fourier Transform infrared spectroscopy. The group without coinitiator has not formed a polymer, whereas the addition of TBA resulted in the conversion of monomers in polymer. The DC of the adhesives was as higher as the increase in the TBA content. The group with 2 mol % of TBA presented improved DC and reactivity (RP) than the other groups and the control one. Hence, the TBA has performed as a coinitiator of the CQ for the radical polymerization of methacrylate resin adhesives and it has improved the DC and the reactivity of the materials. Thus, it is a potential coinitiator for the photopolymerization of dental materials. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 101B: 1217-1221, 2013. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.
  • Publication
    1,3-Disubstituted ferrocene-containing thermotropic liquid crystals of form (η5-C5H5)Fe[(η5-C 5H3)-1,3-(CO2C6H4CO 2C6H4OCnH2n + 1) 2
    ( 1994-01-01)
    Deschenaux R.
    ;
    SANTIAGO CONTRERAS, JULIO CESAR
    ;
    Guillon D.
    ;
    Heinrich B.
    The title compounds have been synthesized and their liquid-crystal properties investigated. The reported ferrocene derivatives exhibited enantiotropic nematic and/or smectic A phases associated with broad anisotropic domains. The molecular arrangement within the smectic A phases was studied by X-ray diffraction. The experimental data, compared to the values obtained from CPK models, suggested a monolayer molecular organization with a pronounced chain disorganization for the medium- and long-chain derivatives.
  • Publication
    [1-8-NαlC]-Zanriorb A1, a Proapoptotic Orbitide from Leaves of Zanthoxylum riedelianum
    (American Chemical Society, 2016-05-27)
    Dos Beirigo P.
    ;
    Torquato H.
    ;
    Dos Santos C.
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    De Carvalho M.
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    Castro R.
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    PAREDES GAMERO, EDGAR JULIAN
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    De Sousa P.
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    Jacinto M.
    ;
    Da Silva V.
    A new orbitide named [1-8-NαC]-zanriorb A1 (1) was isolated and characterized from the leaves of Zanthoxylum riedelianum using NMR and mass spectrometry. The absolute configuration of the amino acids was determined using Marfey's method on the acid hydrolysates. Compound 1 induced cell death by apoptosis in Jurkat leukemia T cells (IC50 218 nM).
  • Publication
  • Publication
    10-pi-Electron arenes a la carte: structure and bonding of the [E-(CnHn)-E](n-6) (E = Ca, Sr, Ba; n=6-8) complexes
    (Royal Society of Chemistry, 2016)
    Mondal, S
    ;
    CABELLOS DAMIAN, RICARDO
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    Pan, S
    ;
    Osorio, E
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    Torres-Vega, JJ
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    Tiznado, W
    ;
    Restrepo, A
    ;
    Merino, G
    In this paper, we provide solid evidence to show that among an overwhelming structural diversity, alkaline earth metals (Ca, Sr, Ba) have the ability to form inverted sandwich compounds with C6H6, C7H7+, and C8H82+ of Dnh symmetry and general formula [E-(CnHn)-E]n-6 (n = 6-8) with planar 10-π-electron aromatic cores by virtue of transferring two electrons per metal atom to the ring. However, the origin of the orbital interaction between the metals and the carbon ring is quite different; while [E-(C6H6)-E] complexes are dominated by δ-interactions, both π- and δ-interactions are important in [E-(C7H7)-E]+ and [E-(C8H8)-E]2+ complexes. © 2016 the Owner Societies.
    Scopus© Citations 21
  • Publication
    10-Year experience on renal cell carcinoma at the instituto de enfermedades neoplasicas
    (Wiley-Blackwell, 1997-12-01)
    Pow-Sang M.
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    CASTILLO VALENCIA, JOSE ARTURO
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    BENAVENTE CORRALES, VICTOR ANGEL
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    POW SANG YUI, JULIO ENRIQUE
    OBJECTIVE. Renal cell carcinoma (RCC) was first described in 1826. We analyse retrospectively 58 pts who underwent radical nephrectomy and determine their survival MATERIALS: Between Januray 1974 and December 1985, 58 pts with RCC underwent radical nephrectomy (nephrectomy and lymphadenectomy). The series comprised 40 males and 18 females (ratio 2.2:1), with a mean age of 66 years (r 13-85). RESULTS: Mean time of symptoms prior to treatment was 1 to 6 months 16 pts (27,5%), and more than 6 monts 42 pts (71,8%). Robson classification of the tumor showed 12 pts stage I (20,7%), 1 stage II (1,7%), 6 stage III (10,3%) and 31 stage IV (53,5%); in 8 pts (13,8%) stage unknown since these pts had surgery in other hospital.Tumor grade was weel differentiated in 21 pts (36,2%), moderatelly differentiated in 20 (34,5%), and poorly differentiated in 4 (6,9%); tumor grade was unknown in 13 (22,4%). Six pts (6,4%) had tumors between 5-1 Ocm, and 33 pts (57%) tumors more than 10cm; in 19 pts (32,7%) tumor size was unknown. There were 5 post-op deathts (8,6%). Five-year survival for stage I was 50% and 41,7% at 10 years. In this group, 2 pts died because of distal metastatic disease at 12 and 16 years, respectively. The only pt in stage II survived for 9 years, at which time developed lung metastasis, dying from the disease. Two-year survival for stage III was 50%, then all pts lost to follow-up. For stage IV, all pts (31/31 - 100%) died within 3 years from surgery. CONCLUSIONS: Our survival is similar to that described in the literaure, as well as surgical mortality. RCC, in their initial stages, will rescue 50% of pts at 5 years, and 41,7% at 10 years.
  • Publication
    100-nm thick single-phase wurtzite BAlN films with boron contents over 10%
    (Wiley-VCH Verlag, 2017-08-01)
    Li X.
    ;
    Wang S.
    ;
    Liu H.
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    PONCE ANTUNEZ DE MAYOLO, FERNANDO AGUSTIN
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    Detchprohm T.
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    Dupuis R.D.
    Growing thicker BAlN films while maintaining single-phase wurtzite structure and boron content over 10% has been challenging. In this study, we report on the growth of 100 nm-thick single-phase wurtzite BAlN films with boron contents up to 14.4% by MOCVD. Flow-modulated epitaxy was employed to increase diffusion length of group-III atoms and reduce parasitic reactions between the metalorganics and NH3. A large growth efficiency of ∼2000 μm mol−1 was achieved as a result. Small B/III ratios up to 17% in conjunction with high temperatures up to 1010 °C were utilized to prevent formation of the cubic phase and maintain wurtzite structure.
  • Publication
    12 novel clonal groups of leptospira infecting humans in multiple contrasting epidemiological contexts in Sri Lanka
    (Public Library of Science, 2021-03-01)
    Jayasundara D.
    ;
    Senavirathna I.
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    Warnasekara J.
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    Gamage C.
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    Siribaddana S.
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    Kularatne S.A.M.
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    Matthias M.
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    Mariet J.F.
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    Picardeau M.
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    Agampodi S.
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    VINETZ, JOSEPH M.
    Leptospirosis is a ubiquitous zoonotic disease and a major clinical challenge owing to the multitude of clinical presentations and manifestations that are possibly attributable to the diversity of Leptospira, the understanding of which is key to study the epidemiology of this emerging global disease threat. Sri Lanka is a hotspot for leptospirosis with high levels of endemicity as well as annual epidemics. We carried out a prospective study of Leptospira diversity in Sri Lanka, covering the full range of climatic zones, geography, and clinical severity. Samples were collected for leptospiral culture from 1,192 patients from 15 of 25 districts in Sri Lanka over two and half years. Twenty-five isolates belonging to four pathogenic Leptospira species were identified: L. interrogans, L. borgpetersenii, L. weilii, and L. kirschneri. At least six serogroups were identified among the isolates: Autumnalis (6), Pyrogenes (4), Icterohaemorrhagiae (2), Celledoni (1), Grippotyphosa (2) and Bataviae (1). Seven isolates did not agglutinate using available antisera panels, suggesting new serogroups. Isolates were sequenced using an Illumina platform. These data add 25 new core genome sequence types and were clustered in 15 clonal groups, including 12 new clonal groups. L. borgpetersenii was found only in the dry zone and L. weilii only in the wet zone. Acute kidney injury and cardiovascular involvement were seen only with L. interrogans infections. Thrombocytopenia and liver impairment were seen in both L. interrogans and L. borgpetersenii infections. The inadequate sensitivity of culture isolation to identify infecting Leptospira species underscores the need for culture-independent typing methods for Leptospira.
  • Publication
    12-O-tetradecanoylphorbol-13-acetate may both potentiate and decrease the generation of apoptosis by the antileukemic agent arsenic trioxide in human promonocytic cells: Regulation by extracellular signal-regulated protein kinases and glutathione
    ( 2004-01-30)
    FERNANDEZ FERNANDEZ, CARLOS FABRICIO
    ;
    Ramos A.M.
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    Sancho P.
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    Amrán D.
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    De Blas E.
    ;
    Aller P.
    Arsenic trioxide (As2O3) caused apoptosis in U-937 human promonocytic cells. This effect was potentiated by the simultaneous addition of the glutathione (GSH) synthesis inhibitor DL-buthionine-(R,S)-sulfoximine or the protein kinase C activators 12-O-tetradecanoylphorbol-13-acetate (TPA) and bryostatin 1. In addition TPA decreased the intracellular GSH content, caused ERK activation, and potentiated the As2O3-provoked activation of p38 and JNK. The addition of N-acetyl-L-cysteine, the PKC inhibitor GF109203X, and the MEK/ERK inhibitors PD98059 and U0126 attenuated both apoptosis induction and GSH decrease, whereas the p38 inhibitor SB203580 and the JNK inhibitor SP600125 were ineffective. TPA also potentiated ERK activation and GSH depletion when added simultaneously to cadmium chloride (CdCl2) and doxorubicin. However, TPA only enhanced apoptosis in the case of CdCl2, which is a GSH-sensitive agent, whereas it reduced the toxicity of doxorubicin and other DNA-specific drugs. Finally, preincubation for 14-24 h with TPA did not potentiate but, instead, attenuated the As2O3- and CdCl2-provoked apoptosis. The same result was obtained by preincubation with bryostatin 1 and other differentiation inducers. It is concluded that TPA increases the apoptotic action of As2O 3, an effect mediated by ERK activation and GSH depletion. However, the increase in apoptosis is only effective in non-differentiated cells.
  • Publication
    (127–135) Proposals to add new Provisions and Recommendations to Division III of the International Code of Nomenclature for algae, fungi, and plants related to virtual participation in the Nomenclature Section: Special-purpose Committee on Virtual Participation in the Nomenclature Section
    (International Association for Plant Taxonomy, 2021-12-01)
    Landrum L.R.
    ;
    Fortunato R.
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    Barkworth M.
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    Breitwieser I.
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    Demissew S.
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    Dönmez A.A.
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    Dutta S.
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    Freire-Fierro A.
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    Kim Y.D.
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    LEON BOCANGEL DE YOUNG, BLANCA ROSA
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    Moore G.
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    Mosyakin S.L.
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    Oh S.H.
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    Parra-O C.
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    Prado J.
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    Arce L.R.
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    Sennikov A.N.
    ;
    Smith G.F.
  • Publication
  • Publication
    13C NMR metabolomics: INADEQUATE network analysis
    (American Chemical Society, 2015-06-02)
    Clendinen C.
    ;
    PASQUEL RODRIGUEZ, CHRISTIAN
    ;
    Ajredini R.
    ;
    Edison A.
    The many advantages of 13C NMR are often overshadowed by its intrinsically low sensitivity. Given that carbon makes up the backbone of most biologically relevant molecules, 13C NMR offers a straightforward measurement of these compounds. Two-dimensional 13C-13C correlation experiments like INADEQUATE (incredible natural abundance double quantum transfer experiment) are ideal for the structural elucidation of natural products and have great but untapped potential for metabolomics analysis. We demonstrate a new and semiautomated approach called INETA (INADEQUATE network analysis) for the untargeted analysis of INADEQUATE data sets using an in silico INADEQUATE database. We demonstrate this approach using isotopically labeled Caenorhabditis elegans mixtures.
  • Publication
    14C AMS dating of fires in the central Amazon rain forest
    (Elsevier, 2000-01-01)
    Santos G.
    ;
    Gomes P.
    ;
    Anjos R.
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    Cordeiro R.
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    TURCQ, BRUNO JEAN
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    SIFEDDINE, ABDELFETTAH
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    Di Tada M.
    ;
    Cresswell R.
    ;
    Fifield L.
    Soil samples were collected in tierra firme upland and lowland areas of the Km 41 reserve near Manaus (20°30′S and 60°W), in Central Brazilian Amazon, within a 1700 m transect, at eight different depth ranges, from surface to 100 cm. The highest charcoal concentrations were found at the depth range of 20-50 cm. AMS radiocarbon dating of 31 samples were performed at the ANU. The ages of the charcoals were found to vary within the 130 to 2400 years BP range, mostly between 1200 and 1400 years BP, one of the known Holocene dry periods of the Amazon region. The results show that the fires have regional dimensions and are associated with climate regional changes. © 2000 Elsevier Science B.V. All rights reserved.