Electron Spin Resonance of SrCu2(BO3)2 at High Magnetic Field

We calculate the electron spin resonance (ESR) spectra of the quasi-two-dimensional dimer spin liquid SrCu2(BO3)2 as a function of magnetic field B. Using the standard Lanczos method, we solve a Shastry-Sutherland Hamiltonian with additional Dzyaloshinsky-Moriya (DM) terms which are crucial to explain different qualitative aspects of the ESR spectra. In particular, a nearest-neighbor DM interaction with a non-zero D_z component is required to explain the low frequency ESR lines for B || c. This suggests that crystal symmetry is lowered at low temperatures due to a structural phase transition.Comment: 4 pages, 4 b&w figure

Working conditions in schools, their influences on health and science teachers’ professional development: a case study with teachers from Bahia

Este estudo pretende identificar quais as influências das condições de trabalho nas escolas para a saúde e a formação do professor de ciências, segundo as visões de professoras de biologia do estado da Bahia. O estudo foi desenvolvido em 2009, baseado em entrevistas semi-estruturadas com com nove professoras. Os resultados indicam que são precárias as condições de trabalho para os professores nas escolas e isto influencia de forma negativa nas suas saúdes, no seu desenvolvimento profissional e nas suas práticas de ensino. É necessária uma articulação de todos os agentes envolvidos com a educação escolar no sentido de contribuir para que melhorias ocorram nas condições de trabalho do professor. Para tanto, é imprescindível, também, a atenção das políticas públicas da educação no país para estes problemas, visto que sua superação pode interferir positivamente nos avanços relativos aos indicadores de qualidade da educação e das condições de trabalho nas escolas.This study aims to identifying the influences of school working conditions on science teachers’ health and education, according to the views of biology teachers from the state of Bahia. The study was based on semi-structured interviews, and was developed in 2009 with nine teachers from public state schools. The results indicate that the teachers’ working conditions in the schools are precarious and, as a result, these professionals suffer negative effects on their health, professional development and teaching practices. An articulation of all the agents involved in schooling is required in order to contribute to significant improvements in the teachers’ working conditions. It is also essential that educational public policies take these problems into account, since overcoming them can interfere positively in advances related to indicators of the quality of education and working conditions in schools.CIEC - Centro de Investigação em Estudos da Criança, UM (UI 317 da FCT

Deformation of Super Virasoro Algebra in Noncommutative Quantum Superspace

We present a twisted commutator deformation for $N=1,2$ super Virasoro algebras based on $GL_q(1,1)$ covariant noncommutative superspace.Comment: 10 pages, Late

Capped Mesoporous Silica Nanoparticles for the Selective and Sensitive Detection of Cyanide

[EN] The development of easy and affordable methods for the detection of cyanide is of great significance due to the high toxicity of this anion and the potential risks associated with its pollution. Herein, optical detection of cyanide in water has been achieved by using a hybrid organic-inorganic nanomaterial. Mesoporous silica nanoparticles were loaded with [Ru(bipy)(3)](2+), functionalized with macrocyclic nickel(II) complex subunits, and capped with a sterically hindering anion (hexametaphosphate). Cyanide selectively induces demetallation of nickel(II) complexes and the removal of capping anions from the silica surface, allowing the release of the dye and the consequent increase in fluorescence intensity. The response of the capped nanoparticles in aqueous solution is highly selective and sensitive towards cyanide with a limit of detection of 2 mu M.We thank the Spanish Government (projects MAT2015-64139-C4-1-R and AGL2015-70235-C2-2-R (MINECO/FEDER, UE)) and the Generalitat Valenciana (project PROMETEOII/2014/047) for support.El Sayed, S.; Licchelli, M.; Martínez-Máñez, R.; Sancenón Galarza, F. (2017). Capped Mesoporous Silica Nanoparticles for the Selective and Sensitive Detection of Cyanide. Chemistry - An Asian Journal. 12(20):2670-2674. https://doi.org/10.1002/asia.201701130S267026741220Tylleskar, T., Howlett, W. P., Rwiza, H. T., Aquilonius, S. M., Stalberg, E., Linden, B., … Rosling, H. (1993). Konzo: a distinct disease entity with selective upper motor neuron damage. Journal of Neurology, Neurosurgery & Psychiatry, 56(6), 638-643. doi:10.1136/jnnp.56.6.638Johnson, J. D., Meisenheimer, T. L., & Isom, G. E. (1986). Cyanide-induced neurotoxicity: Role of neuronal calcium. Toxicology and Applied Pharmacology, 84(3), 464-469. doi:10.1016/0041-008x(86)90251-6Cyanide Toxicity 1991Jiang, J., Wang, X., Zhou, W., Gao, H., & Wu, J. (2002). Extraction of gold from alkaline cyanide solution by the tetradecyldimethylbenzylammonium chloride/tri-n-butyl phosphate/n-heptane system based on a microemulsion mechanism. Physical Chemistry Chemical Physics, 4(18), 4489-4494. doi:10.1039/b203467kGuidelines for drinking-water quality 2011Standard Methods for the Examination of Water and Wastewater 22nd ed 2012Suzuki, T., Hioki, A., & Kurahashi, M. (2003). Development of a method for estimating an accurate equivalence point in nickel titration of cyanide ions. Analytica Chimica Acta, 476(1), 159-165. doi:10.1016/s0003-2670(02)01362-4Safavi, A., Maleki, N., & Shahbaazi, H. . (2004). Indirect determination of cyanide ion and hydrogen cyanide by adsorptive stripping voltammetry at a mercury electrode. Analytica Chimica Acta, 503(2), 213-221. doi:10.1016/j.aca.2003.10.032Wang, F., Wang, L., Chen, X., & Yoon, J. (2014). Recent progress in the development of fluorometric and colorimetric chemosensors for detection of cyanide ions. Chemical Society Reviews, 43(13), 4312. doi:10.1039/c4cs00008kLin, W.-C., Fang, S.-K., Hu, J.-W., Tsai, H.-Y., & Chen, K.-Y. (2014). Ratiometric Fluorescent/Colorimetric Cyanide-Selective Sensor Based on Excited-State Intramolecular Charge Transfer−Excited-State Intramolecular Proton Transfer Switching. Analytical Chemistry, 86(10), 4648-4652. doi:10.1021/ac501024dWang, L., Zhu, L., & Cao, D. (2015). A colorimetric probe based on diketopyrrolopyrrole and tert-butyl cyanoacetate for cyanide detection. New Journal of Chemistry, 39(9), 7211-7218. doi:10.1039/c5nj01214gSingh, P., Mittal, L. S., Kumar, S., Bhargava, G., & Kumar, S. (2014). Perylene Diimide Appended with 8-Hydroxyquinoline for Ratiometric Detection of Cu2+ Ions and Metal Displacement Driven «Turn on» Cyanide Sensing. Journal of Fluorescence, 24(3), 909-915. doi:10.1007/s10895-014-1371-6Hong, K.-I., Yoon, H., & Jang, W.-D. (2015). A triazole-bearing picket fence type nickel porphyrin as a cyanide selective allosteric host. Chemical Communications, 51(35), 7486-7488. doi:10.1039/c5cc00809cBatista, R. M. F., Oliveira, E., Costa, S. P. G., Lodeiro, C., & Raposo, M. M. M. (2013). Cyanide and fluoride colorimetric sensing by novel imidazo-anthraquinones functionalised with indole and carbazole. Supramolecular Chemistry, 26(2), 71-80. doi:10.1080/10610278.2013.824082Gale, P. A., & Caltagirone, C. (2015). Anion sensing by small molecules and molecular ensembles. Chemical Society Reviews, 44(13), 4212-4227. doi:10.1039/c4cs00179fShiraishi, Y., Nakamura, M., Kogure, T., & Hirai, T. (2016). Off–on fluorometric detection of cyanide anions in an aqueous mixture by an indane-based receptor. New Journal of Chemistry, 40(2), 1237-1243. doi:10.1039/c5nj02873fBejoymohandas, K. S., Kumar, A., Sreenadh, S., Varathan, E., Varughese, S., Subramanian, V., & Reddy, M. L. P. (2016). A Highly Selective Chemosensor for Cyanide Derived from a Formyl-Functionalized Phosphorescent Iridium(III) Complex. Inorganic Chemistry, 55(7), 3448-3461. doi:10.1021/acs.inorgchem.5b02885Sancenón, F., Pascual, L., Oroval, M., Aznar, E., & Martínez-Máñez, R. (2015). Gated Silica Mesoporous Materials in Sensing Applications. ChemistryOpen, 4(4), 418-437. doi:10.1002/open.201500053El Sayed, S., Pascual, L., Licchelli, M., Martínez-Máñez, R., Gil, S., Costero, A. M., & Sancenón, F. (2016). Chromogenic Detection of Aqueous Formaldehyde Using Functionalized Silica Nanoparticles. 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Acetylcholinesterase-Capped Mesoporous Silica Nanoparticles That Open in the Presence of Diisopropylfluorophosphate (a Sarin or Soman Simulant). Organic Letters, 18(21), 5548-5551. doi:10.1021/acs.orglett.6b02793El Sayed, S., Giménez, C., Aznar, E., Martínez-Máñez, R., Sancenón, F., & Licchelli, M. (2015). Highly selective and sensitive detection of glutathione using mesoporous silica nanoparticles capped with disulfide-containing oligo(ethylene glycol) chains. Organic & Biomolecular Chemistry, 13(4), 1017-1021. doi:10.1039/c4ob02083aEl Sayed, S., Milani, M., Licchelli, M., Martínez-Máñez, R., & Sancenón, F. (2015). Hexametaphosphate-Capped Silica Mesoporous Nanoparticles Containing CuIIComplexes for the Selective and Sensitive Optical Detection of Hydrogen Sulfide in Water. Chemistry - A European Journal, 21(19), 7002-7006. doi:10.1002/chem.201500360Attia, S., Shames, A., Zilbermann, I., Goobes, G., Maimon, E., & Meyerstein, D. (2014). Covalent binding of a nickel macrocyclic complex to a silica support: towards an electron exchange column. Dalton Trans., 43(1), 103-110. doi:10.1039/c3dt51962gFabbrizzi, L., Licchelli, M., Manotti Lanfredi, A. M., Vassalli, O., & Ugozzoli, F. (1996). Template Synthesis of a Tetraaza Macrocycle Which Involves Benzaldehyde Rather Than Formaldehyde as a Building Block. Isolation and Structure Determination of the Open-Chain Schiff Base Intermediate Complex. Inorganic Chemistry, 35(6), 1582-1589. doi:10.1021/ic950841kBoiocchi, M., Licchelli, M., Milani, M., Poggi, A., & Sacchi, D. (2014). Oxo-Anion Recognition by Mono- and Bisurea Pendant-Arm Macrocyclic Complexes. Inorganic Chemistry, 54(1), 47-58. doi:10.1021/ic501527kFabbrizzi, L., Licchelli, M., Mosca, L., & Poggi, A. (2010). Template synthesis of azacyclam metal complexes using primary amides as locking fragments. Coordination Chemistry Reviews, 254(15-16), 1628-1636. doi:10.1016/j.ccr.2009.12.002Hinz, F. P., & Margerum, D. W. (1974). Ligand solvation and the macrocyclic effect. Nickel(II)-tetramine complexes. Inorganic Chemistry, 13(12), 2941-2949. doi:10.1021/ic50142a032El Sayed, S., Milani, M., Milanese, C., Licchelli, M., Martínez-Máñez, R., & Sancenón, F. (2016). Anions as Triggers in Controlled Release Protocols from Mesoporous Silica Nanoparticles Functionalized with Macrocyclic Copper(II) Complexes. Chemistry - A European Journal, 22(39), 13935-13945. doi:10.1002/chem.201601024Wang, L., Zhu, L., Li, L., & Cao, D. (2016). Tetraphenylethene-functionalized diketopyrrolopyrrole solid state emissive molecules: enhanced emission in the solid state and as a fluorescent probe for cyanide detection. RSC Advances, 6(60), 55182-55193. doi:10.1039/c6ra10073bWang, L., Li, L., & Cao, D. (2016). Dual binding site assisted chromogenic and fluorogenic discrimination of fluoride and cyanide by boryl functionalized BODIPY. 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In vivo activity of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida species

<p>Abstract</p> <p>Background</p> <p>Study of <it>in vivo </it>antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of <it>Sapindus saponaria </it>against azole-susceptible and -resistant human vaginal <it>Candida </it>spp.</p> <p>Methods</p> <p>The <it>in vitro </it>antifungal activity of HE, BUTE, fluconazole (FLU), and itraconazole (ITRA) was determined by the broth microdilution method. We obtained values of minimal inhibitory concentration (MIC) and minimum fungicide concentration (MFC) for 46 strains of <it>C. albicans </it>and 10 of <it>C. glabrata </it>isolated from patients with vulvovaginal candidiasis (VVC). VVC was induced in hyperestrogenic Wistar rats with azole-susceptible <it>C. albicans </it>(SCA), azole-resistant <it>C. albicans </it>(RCA), and azole-resistant <it>C. glabrata </it>(RCG). The rats were treated intravaginally with 0.1 mL of HE or BUTE at concentrations of 1%, 2.5% and 5%; 100 μg/mL of FLU (treatment positive control); or distilled water (negative control) at 1, 24, and 48 h after induction of the infection, and the progress of VVC was monitored by culturing and scanning electron microscopy (SEM). The toxicity was evaluated in cervical cells of the HeLa cell line.</p> <p>Results</p> <p>The extracts showed <it>in vitro </it>inhibitory and fungicidal activity against all the isolates, and the MIC and MFC values for the <it>C. glabrata </it>isolates were slightly higher. <it>In vivo</it>, the SCA, RCA, and RCG infections were eliminated by 21 days post-infection, with up to 5% HE and BUTE, comparable to the activity of FLU. No cytotoxic action was observed for either extract.</p> <p>Conclusions</p> <p>Our results demonstrated that HE and BUTE from <it>S. saponaria </it>show inhibitory and fungicidal activity <it>in vitro</it>, in addition to <it>in vivo </it>activity against azole-resistant vaginal isolates of <it>C. glabrata </it>and azole-susceptible and resistant isolates of <it>C. albicans</it>. Also considering the lack of cytotoxicity and the low concentrations of the extracts necessary to eliminate the infection <it>in vivo</it>, HE and BUTE show promise for continued studies with purified antifungal substances in VVC yeast isolates.</p

Insetos nocivos à soja no município de Paragominas, PA.

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