323 research outputs found
Physical properties of thermoelectric zinc antimonide using first-principles calculations
We report first principles calculations of the structural, electronic,
elastic and vibrational properties of the semiconducting orthorhombic ZnSb
compound. We study also the intrinsic point defects in order to eventually
improve the thermoelectric properties of this already very promising
thermoelectric material. Concerning the electronic properties, in addition to
the band structure, we show that the Zn (Sb) crystallographically equivalent
atoms are not exactly equivalent from the electronic point of view. Lattice
dynamics, elastic and thermodynamic properties are found to be in good
agreement with experiments and they confirm the non equivalency of the zinc and
antimony atoms from the vibrational point of view. The calculated elastic
properties show a relatively weak anisotropy and the hardest direction is the y
direction. We observe the presence of low energy modes involving both Zn and Sb
atoms at about 5-6 meV, similarly to what has been found in Zn4Sb3 and we
suggest that the interactions of these modes with acoustic phonons could
explain the relatively low thermal conductivity of ZnSb. Zinc vacancies are the
most stable defects and this explains the intrinsic p-type conductivity of
ZnSb.Comment: 33 pages, 8 figure
Pharmacological preconditioning by incretinomimetics exenatide and vildagliptin: decrement of liver ischemia-reperfusion injury
Study of hepatoprotective activity of exenatide and vildagliptin on the liver ischemia/reperfusion model, taking into account biochemical and morphological parameter
Experimental study of new derivatives of 3-hydroxypyridine as pharmacological agents for the correction of ischemic brain injury after intracerebral hemorrhage
Limiting the action of secondary injury factors can improve the prognosis in acute cerebral accidents. The aim of the investigation is to study the neuroprotective effects of 3-hydroxypyridine derivative
Orbital-selective band hybridisation at the charge density wave transition in monolayer TiTe2
Funding: We gratefully acknowledge support from the Leverhulme Trust and the Royal Society. W.R. is grateful to University College London for awarding a Graduate Research Scholarship and an Overseas Research Scholarship. O.J.C. and K.U. acknowledge PhD studentship support from the UK Engineering and Physical Sciences Research Council (EPSRC, Grant Nos. EP/K503162/1 and EP/L015110/1). I.M. and E.A.-M. acknowledge studentship support from the International Max-Planck Research School for Chemistry and Physics of Quantum Materials. S.R.K. acknowledges the EPSRC Centre for Doctoral Training in the Advanced Characterisation of Materials (CDT-ACM, EP/S023259/1) for funding a PhD studentship.Reducing the thickness of a material to its two dimensional (2D) limit can have dramatic consequences for its collective electronic states, including magnetism, superconductivity, and charge and spin ordering. An extreme case is TiTe2, where a charge density wave (CDW) emerges in the single-layer which is absent for the bulk compound, and whose origin is still poorly understood. Here, we investigate the electronic band structure evolution across this CDW transition using temperature-dependent angle-resolved photoemission spectroscopy. Our study reveals an orbital-selective band hybridisation between the backfolded conduction and valence bands occurring at the CDW phase transition, which in turn leads to a significant electronic energy gain, underpinning the CDW transition. For the bulk compound, we show how this energy gain is almost completely suppressed due to the three-dimensionality of the electronic band structure, including via a kz-dependent band inversion which switches the orbital character of the valence states. Our study thus sheds new light on how control of the electronic dimensionality can be used to trigger the emergence of new collective states in 2D materials.Publisher PDFPeer reviewe
Influence of Obtaining Conditions on Kinetics of the Initial Sintering Stage of Zirconia Nanopowders
Investigation of the neuro-electrostimulation mechanisms by means of the functional MRI: Case study
The article overviewed contemporary neuromodulation approaches and challenges. The importance of the neurostimulation techniques was justified. The SYMPATHOCOR-01 neuro-electrostimulation device characterization was presented. The case study of the neuro-electrostimulation mechanisms by means of the neuroimaging was described. Case study consisted of 3 phases: imaging prior to the neuro-electrostimulation procedure, imaging right after the neuro-electrostimulation procedure and imaging after a 5-day stimulation course. Results of the functional magnetic resonance imaging revealed improvement of the functional connectivity strength in several brain regions as well as normalization of default mode network activity. Copyright © 2018 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved.The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006. The authors thank Ivan Brak, Elena Filimonova and Eugenia Kobeleva for participation in the data processing
Uniparental Genetic Heritage of Belarusians: Encounter of Rare Middle Eastern Matrilineages with a Central European Mitochondrial DNA Pool
Ethnic Belarusians make up more than 80% of the nine and half million people inhabiting the Republic of Belarus. Belarusians together with Ukrainians and Russians represent the East Slavic linguistic group, largest both in numbers and territory, inhabiting East Europe alongside Baltic-, Finno-Permic- and Turkic-speaking people. Till date, only a limited number of low resolution genetic studies have been performed on this population. Therefore, with the phylogeographic analysis of 565 Y-chromosomes and 267 mitochondrial DNAs from six well covered geographic sub-regions of Belarus we strove to complement the existing genetic profile of eastern Europeans. Our results reveal that around 80% of the paternal Belarusian gene pool is composed of R1a, I2a and N1c Y-chromosome haplogroups – a profile which is very similar to the two other eastern European populations – Ukrainians and Russians. The maternal Belarusian gene pool encompasses a full range of West Eurasian haplogroups and agrees well with the genetic structure of central-east European populations. Our data attest that latitudinal gradients characterize the variation of the uniparentally transmitted gene pools of modern Belarusians. In particular, the Y-chromosome reflects movements of people in central-east Europe, starting probably as early as the beginning of the Holocene. Furthermore, the matrilineal legacy of Belarusians retains two rare mitochondrial DNA haplogroups, N1a3 and N3, whose phylogeographies were explored in detail after de novo sequencing of 20 and 13 complete mitogenomes, respectively, from all over Eurasia. Our phylogeographic analyses reveal that two mitochondrial DNA lineages, N3 and N1a3, both of Middle Eastern origin, might mark distinct events of matrilineal gene flow to Europe: during the mid-Holocene period and around the Pleistocene-Holocene transition, respectively
Membrane-Proximal Epitope Facilitates Efficient T Cell Synapse Formation by Anti-FcRH5/CD3 and Is a Requirement for Myeloma Cell Killing
The anti-FcRH5/CD3 T cell-dependent bispecific antibody (TDB) targets the B cell lineage marker FcRH5 expressed in multiple myeloma (MM) tumor cells. We demonstrate that TDBs trigger T cell receptor activation by inducing target clustering and exclusion of CD45 phosphatase from the synapse. The dimensions of the target molecule play a key role in the efficiency of the synapse formation. The anti-FcRH5/CD3 TDB kills human plasma cells and patient-derived myeloma cells at picomolar concentrations and results in complete depletion of B cells and bone marrow plasma cells in cynomolgus monkeys. These data demonstrate the potential for the anti-FcRH5/CD3 TDB, alone or in combination with inhibition of PD-1/PD-L1 signaling, in the treatment of MM and other B cell malignancies.This work was supported by a Sir Henry Dale Fellowship (J.R.J.) jointly funded by the Wellcome Trust and the Royal Society (grant number: 099966/Z/12/Z). PhD studentships (S.A.M. and M.J.H.) were funded by the Wellcome Trust (grant number: 102195/Z/13/Z)
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