181 research outputs found
High pressure phases in highly piezoelectric Pb(Zr0.52Ti0.48)O3
Two novel room-temperature phase transitions are observed, via synchrotron
x-ray diffraction and Raman spectroscopy, in the Pb(Zr0.52Ti0.48)O3 alloy under
hydrostatic pressures up to 16 GPa. A monoclinic (M)-to-rhombohedral (R1) phase
transition takes place around 2-3 GPa, while this R1 phase transforms into
another rhombohedral phase, R2, at about 6-7 GPa. First-principles calculations
assign the R3m and R3c symmetry to R1 and R2, respectively, and reveal that R2
acts as a pressure-induced structural bridge between the polar R3m and a
predicted antiferrodistortive R-3c phase.Comment: REVTeX, 4 pages with 3 figures embedded. Figs 1 and 3 in colo
Synthesis, Infra-red, Raman, NMR and structural characterization by X-ray Diffraction of [C12H17N2]2CdCl4 and [C6H10N2]2Cd3Cl10 compounds
The synthesis, infra-red, Raman and NMR spectra and crystal structure of 2,
4, 4- trimethyl-4, 5- dihydro-3H-benzo[b] [1, 4] diazepin-1-ium
tetrachlorocadmate, [C12H17N2]2CdCl4 and benzene-1,2-diaminium
decachlorotricadmate(II) [C6H10N2]2Cd3Cl10 are reported.
The [C12H17N2]2CdCl4 compound crystallizes in the triclinic system (P-1 space
group) with Z = 2 and the following unit cell dimensions: a = 9.6653(8)
angstrom, b = 9.9081(9) angstrom, c = 15.3737(2) angstrom, alpha =
79.486(1)degrees, beta = 88.610(8)degrees and gamma = 77.550(7)degrees. The
structure was solved by using 4439 independent reflections down to R value of
0.029. In crystal structure, the tetrachlorocadmiate anion is connected to two
organic cations through N-H...Cl hydrogen bonds and Van Der Waals interaction
as to build cation-anion-cation cohesion. The [C6H10N2]2Cd3Cl10 crystallizes in
the triclinic system (P-1 space group). The unit cell dimensions are a = 6.826
(5)angstrom, b = 9.861 (7)angstrom, c = 10.344 (3)angstrom, alpha = 103.50
(1)degrees, beta = 96.34 (4)degrees and gamma = 109.45 (3)degrees, Z=2. The
final R value is 0.053 (Rw=0.128). Its crystal structure consists of organic
cations and polymeric chains of [Cd3Cl10]4- anions running along the [011]
direction, In The [C6H10N2]2Cd3Cl10 compounds hydrogen bond interactions
between the inorganic chains and the organic cations, contribute to the crystal
packing.
PACS Codes: 61.10.Nz, 61.18.Fs, 78.30.-jComment: 19 pages, 10 figure
ITERATED QUASI-REVERSIBILITY METHOD APPLIED TO ELLIPTIC AND PARABOLIC DATA COMPLETION PROBLEMS
International audienceWe study the iterated quasi-reversibility method to regularize ill-posed elliptic and parabolic problems: data completion problems for Poisson's and heat equations. We define an abstract setting to treat both equations at once. We demonstrate the convergence of the regularized solution to the exact one, and propose a strategy to deal with noise on the data. We present numerical experiments for both problems: a two-dimensional corrosion detection problem and the one-dimensional heat equation with lateral data. In both cases, the method prove to be efficient even with highly corrupted data
Animal influence on water, sanitation and hygiene measures for zoonosis control at the household level: A systematic literature review
Neglected zoonotic diseases (NZDs) have a significant impact on the livelihoods of the worldâs poorest populations, which often lack access to basic services. Water, sanitation and hygiene (WASH) programmes are included among the key strategies for achieving the World Health Organizationâs 2020 Roadmap for Implementation for control of Neglected Tropical Diseases (NTDs). There exists a lack of knowledge regarding the effect of animals on the effectiveness of WASH measures. This review looked to identify how animal presence in the household influences the effectiveness of water, hygiene and sanitation measures for zoonotic disease control in low and middle income countries; to identify gaps of knowledge regarding this topic based on the amount and type of studies looking at this particular interaction
Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences
The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009aâb; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported
by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on
18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based
researchers who signed it in the short time span from 20 September to 6 October 2016
Differential regulation of cell death pathways by the microenvironment correlates with chemoresistance and survival in leukaemia
Glucocorticoids (GCs) and topoisomerase II inhibitors are used to treat acute lymphoblastic leukaemia (ALL) as they induce death in lymphoid cells through the glucocorticoid receptor (GR) and p53 respectively. Mechanisms underlying ALL cell death and the contribution of the bone marrow microenvironment to drug response/resistance remain unclear. The role of the microenvironment and the identification of chemoresistance determinants were studied by transcriptomic analysis in ALL cells treated with Dexamethasone (Dex), and Etoposide (Etop) grown in the presence or absence of bone marrow conditioned media (CM). The necroptotic (RIPK1) and the apoptotic (caspase-8/3) markers were downregulated by CM, whereas the inhibitory effects of chemotherapy on the autophagy marker Beclin-1 (BECN1) were reduced suggesting CM exerts cytoprotective effects. GCs upregulated the RIPK1 ubiquitinating factor BIRC3 (cIAP2), in GC-sensitive (CEM-C7-14) but not in resistant (CEM-C1-15) cells. In addition, CM selectively affected GR phosphorylation in a site and cell-specific manner. GR is recruited to RIPK1, BECN1 and BIRC3 promoters in the sensitive but not in the resistant cells with phosphorylated GR forms being generally less recruited in the presence of hormone. FACS analysis and caspase-8 assays demonstrated that CM promoted a pro-survival trend. High molecular weight proteins reacting with the RIPK1 antibody were modified upon incubation with the BIRC3 inhibitor AT406 in CEM-C7-14 cells suggesting that they represent ubiquitinated forms of RIPK1. Our data suggest that there is a correlation between microenvironment-induced ALL proliferation and altered response to chemotherapy
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