73 research outputs found
Magnetic properties of chain antiferromagnets RbFeSe<inf>2</inf>, TlFeSe<inf>2</inf>, and TlFeS<inf>2</inf>
© 2017, Allerton Press, Inc. Single crystals of ternary ion chalcogenides RbFeSe 2 , TlFeSe 2 , and TlFeS 2 are studied by X-ray diffraction, SQUID magnetometry, and Mössbauer spectroscopy. Common structural units of these chalcogenides are tetrahedra of FeCh 4 (chalcogen Ch = Se, S), arranged in chains by sharing an edge. It is found that RbFeSe 2 , TlFeSe 2 , and TlFeS 2 undergo transition to a collinear antiferromagnetic state below temperatures T N = 248, 290, and 196 K, respectively. Their magnetic moments are oriented perpendicular to the axes of the chains of FeCh 4 tetrahedra
Spatially, Temporally and Polarization-Resolved Photoluminescence Exploration of Excitons in Crystalline Phthalocyanine Thin Films
The lack of long range order in organic semiconductor thin films prevents the
unveiling of the complete nature of excitons in optical experiments, because
the diffraction limited beam diameters in the bandgap region far exceed typical
crystalline grain sizes. Here we present spatially-, temporally- and
polarization-resolved dual photoluminescence/linear dichroism microscopy
experiments that investigate exciton states within a single crystalline grain
in solution-processed phthalocyanine thin films. These experiments reveal the
existence of a delocalized singlet exciton, polarized along the high mobility
axis in this quasi-1D electronic system. The strong delocalized {\pi} orbitals
overlap controlled by the molecular stacking along the high mobility axis is
responsible for breaking the radiative recombination selection rules. Using our
linear dichroism scanning microscopy setup we further established a rotation of
molecules (i.e. a structural phase transition) that occurs above 100 K prevents
the observation of this exciton at room temperature.Comment: submitted to Journal of Chem Phys letter
The cytotoxic T cell proteome and its shaping by the kinase mTOR
High-resolution mass spectrometry maps the cytotoxic T lymphocyte (CTL) proteome and the impact of mammalian target of rapamycin complex 1 (mTORC1) on CTLs. The CTL proteome was dominated by metabolic regulators and granzymes and mTORC1 selectively repressed and promoted expression of subset of CTL proteins (~10%). These included key CTL effector molecules, signaling proteins and a subset of metabolic enzymes. Proteomic data highlighted the potential for mTORC1 negative control of phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P(3)) production in CTL. mTORC1 was shown to repress PtdIns(3,4,5)P(3) production and to determine the mTORC2 requirement for activation of the kinase Akt. Unbiased proteomic analysis thus provides a comprehensive understanding of CTL identity and mTORC1 control of CTL function
PDK1-mTOR signaling pathway inhibitors reduce cell proliferation in MK2206 resistant neuroblastoma cells
Vacancy mediated magnetization and healing of a graphene monolayer
Vacancy-induced magnetization of a graphene layer is investigated by means of a first-principles DFT method. Calculations of the formation energy and the magnetization by creating the different number of vacancies in a supercell show that a clustering with a big number of vacancies in the cluster is rather favorable to that of isolated vacancies, homogeneously distributed in the layer. The magnetic moment of a cluster with a big number of vacancies is shown to not be proportional with the vacancy concentration, which is in good agreement with the recent experimental results. Our studies support the idea that, although the vacancies in graphene create a magnetic moment, they do not produce a magnetic ordering. It is shown that, although the Lieb's rule for the magnetization in a hexagonal structure violates, two vacancies, including a di-vacancy, in the supercell generates a quasilocalized state when they belong to the different sublattices and, instead, two vacancies generate an extended state when they belong to the same sublattices. Analytical investigation of the dynamics of carbon atom and vacancy concentrations according to the nonlinear continuity equations shows that the vacancies, produced by irradiation at the middle of a graphene layer, migrate to the edge of the sample, resulting in a specific “segregation” of the vacancy concentration and self-healing of the graphene
Magnetic properties of chain antiferromagnets RbFeSe<inf>2</inf>, TlFeSe<inf>2</inf>, and TlFeS<inf>2</inf>
© 2017, Allerton Press, Inc. Single crystals of ternary ion chalcogenides RbFeSe 2 , TlFeSe 2 , and TlFeS 2 are studied by X-ray diffraction, SQUID magnetometry, and Mössbauer spectroscopy. Common structural units of these chalcogenides are tetrahedra of FeCh 4 (chalcogen Ch = Se, S), arranged in chains by sharing an edge. It is found that RbFeSe 2 , TlFeSe 2 , and TlFeS 2 undergo transition to a collinear antiferromagnetic state below temperatures T N = 248, 290, and 196 K, respectively. Their magnetic moments are oriented perpendicular to the axes of the chains of FeCh 4 tetrahedra
Magnetic properties of chain antiferromagnets RbFeSe<inf>2</inf>, TlFeSe<inf>2</inf>, and TlFeS<inf>2</inf>
© 2017, Allerton Press, Inc. Single crystals of ternary ion chalcogenides RbFeSe 2 , TlFeSe 2 , and TlFeS 2 are studied by X-ray diffraction, SQUID magnetometry, and Mössbauer spectroscopy. Common structural units of these chalcogenides are tetrahedra of FeCh 4 (chalcogen Ch = Se, S), arranged in chains by sharing an edge. It is found that RbFeSe 2 , TlFeSe 2 , and TlFeS 2 undergo transition to a collinear antiferromagnetic state below temperatures T N = 248, 290, and 196 K, respectively. Their magnetic moments are oriented perpendicular to the axes of the chains of FeCh 4 tetrahedra
Magnetic properties of chain antiferromagnets RbFeSe<inf>2</inf>, TlFeSe<inf>2</inf>, and TlFeS<inf>2</inf>
© 2017, Allerton Press, Inc. Single crystals of ternary ion chalcogenides RbFeSe 2 , TlFeSe 2 , and TlFeS 2 are studied by X-ray diffraction, SQUID magnetometry, and Mössbauer spectroscopy. Common structural units of these chalcogenides are tetrahedra of FeCh 4 (chalcogen Ch = Se, S), arranged in chains by sharing an edge. It is found that RbFeSe 2 , TlFeSe 2 , and TlFeS 2 undergo transition to a collinear antiferromagnetic state below temperatures T N = 248, 290, and 196 K, respectively. Their magnetic moments are oriented perpendicular to the axes of the chains of FeCh 4 tetrahedra
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