314 research outputs found

    2-Hydr­oxy-5-nitro­benzaldehyde 2,4-dinitro­phenyl­hydrazone

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    In the title compound, C13H9N5O7, one of the nitro groups is twisted away from the attached benzene ring by 16.21 (8)°. The dihedral angle between the two benzene rings is 4.63 (1)°. The mol­ecular structure is stabilized by intra­molecular N—H⋯O and O—H⋯N hydrogen bonds which generate an S(6) ring motif. The mol­ecules pack as layers parallel to the ab plane; mol­ecules of adjacent layers are linked into chains along the [101] direction through N—H⋯O hydrogen bonds

    Photoswitchable fluorescent diheteroarylethenes: substituent effects on photochromic and solvatochromic properties

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    Photoswitchable fluorescent diheteroarylethenes are promising candidates for applications in super-resolution molecular localization fluorescence microscopy thanks to their high quantum yields and fatigue-resistant photoswitching characteristics. We have studied the effect of varying substituents on the photophysical properties of six sulfone derivatives of diheteroarylethenes, which display fluorescence in one (closed form) of two thermally stable photochromic states. Electron-donating substituents displace the absorption and emission spectra towards the red without substantially affecting the fluorescence quantum yields. Furthermore, ethoxybromo, a very electron-donating substituent, stabilizes the excited state of the closed isomer to the extent of almost entirely inhibiting its cycloreversion. Multi-parameter Hammett correlations indicate a relationship between the emission maxima and electron-donating character, providing a useful tool in the design of future photochromic molecules. Most of the synthesized compounds exhibit small bathochromic shifts and shorter fluorescence lifetimes with an increase in solvent polarity. However, the ethoxybromo-substituted fluorescent photochrome is unique in its strong solvatochromic behaviour, constituting a photoactivatable (photochromic), fluorescent and highly solvatochromic small organic compound. The Catalán formalism identified solvent dipolarity as the principal basis of the solvatochromism, reflecting the highly polarized nature of this molecule.Fil: Gillanders, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Giordano, Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Diaz, Sebastian Andres. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Jovin, Tomás. Max Planck Institute for Biophysical Chemistry. Laboratory of Cellular Dynamics; AlemaniaFil: Jares, Elizabeth Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones en Hidratos de Carbono; Argentin

    The impact of foreign direct investment, foreign aid and trade on poverty reduction : evidence from Sub-Saharan African countries

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    Abstract:Despite postulations on the effects of foreign direct investment (FDI), foreign aid, and trade on growth, empirical evidence from extant research has been mixed. The focus of recent research has shifted from the growth effects of these international flows to their poverty reduction effects. However, results have also been mixed. Most studies have examined the empirical evidence of these flows separately and have mostly conducted single country studies. In this study, we use data from twenty-nine countries in Sub-Saharan Africa between the period 1990–2017 to analyze the effects of FDI, trade, and foreign aid on poverty reduction in a single model using the Feasible Generalized Least Square (FGLS) technique. Our results show that FDI and foreign aid have a negative effect on poverty reduction in the countries studied. These results suggest that the level of FDI required to alleviate poverty has not been reached, and foreign aid have not been properly channeled. However, the results show that trade has a positive and significant impact on poverty reduction, especially in low-income countries. We conclude with policy recommendations

    Aqueous hydroxylation mediated synthesis of crystalline calcium uranate particles

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    Metal uranates(VI) are solubility limiting U(VI) phases under high pH conditions and may act as suitable long-term wasteforms. The precipitation and thermal phase development mechanisms of calcium uranate particles formed via aqueous hydroxylation reactions are studied in order to address the lack of aqueous synthesis methods currently available. Hydrous Ca-deficient uranate particles formed from aqueous solutions saturated in U(VI) oligomers were found to thermally decompose via several weight-loss steps between 100 and 800 °C. Crystalline calcium uranate (Ca2U3O11) is initially formed at 700 °C via dehydration and dehydroxylation-olation reactions under redox-neutral conditions. This initial phase decomposes to biphasic CaUO4-UO2 particles at 800 °C via a reductive pathway

    Cardiac Alpha-Myosin (MYH6) Is the Predominant Sarcomeric Disease Gene for Familial Atrial Septal Defects

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    Secundum-type atrial septal defects (ASDII) account for approximately 10% of all congenital heart defects (CHD) and are associated with a familial risk. Mutations in transcription factors represent a genetic source for ASDII. Yet, little is known about the role of mutations in sarcomeric genes in ASDII etiology. To assess the role of sarcomeric genes in patients with inherited ASDII, we analyzed 13 sarcomeric genes (MYH7, MYBPC3, TNNT2, TCAP, TNNI3, MYH6, TPM1, MYL2, CSRP3, ACTC1, MYL3, TNNC1, and TTN kinase region) in 31 patients with familial ASDII using array-based resequencing. Genotyping of family relatives and control subjects as well as structural and homology analyses were used to evaluate the pathogenic impact of novel non-synonymous gene variants. Three novel missense mutations were found in the MYH6 gene encoding alpha-myosin heavy chain (R17H, C539R, and K543R). These mutations co-segregated with CHD in the families and were absent in 370 control alleles. Interestingly, all three MYH6 mutations are located in a highly conserved region of the alpha-myosin motor domain, which is involved in myosin-actin interaction. In addition, the cardiomyopathy related MYH6-A1004S and the MYBPC3-A833T mutations were also found in one and two unrelated subjects with ASDII, respectively. No mutations were found in the 11 other sarcomeric genes analyzed. The study indicates that sarcomeric gene mutations may represent a so far underestimated genetic source for familial recurrence of ASDII. In particular, perturbations in the MYH6 head domain seem to play a major role in the genetic origin of familial ASDII

    Donors, Aid and Taxation in Developing Countries: An Overview

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    Recent years have witnessed rapidly growing donor interest in tax issues in the developing world. This reflects a concern with revenue collection to finance public spending, but also recognition of the centrality of taxation to growth, redistribution and broader state-building and governance goals. Against this backdrop, this paper identifies a series of key issues that demand attention if donors are to improve the quality of their support for tax reform. The focus is not, primarily, on the technical design of tax interventions, but, instead, on seven ‘big picture’ considerations for the design of donor programmes: (a) supporting local leadership of reform efforts; (b) incorporating more systematic political economy analysis into the design and implementation of reform programmes; (c) designing tax reform programmes that seek to foster broader linkages between taxation, state-building and governance; (d) paying careful attention to the complexity of the relationship between aid and tax effort; (e) better designing tax-related conditionality, particularly by developing a more nuanced set of performance indicators; (f) ensuring the effective coordination of donor interventions; and (g) paying greater attention to the international policy context, and particularly the role of tax exemptions for donor projects, tax havens and tax evasion by multinational corporations (MNCs) in undermining developing country tax systems.DfI
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