6,713 research outputs found
Unprecedented Zeolite-Like Framework Topology Constructed from Cages with 3-Rings in a Barium Oxonitridophosphate
A novel oxonitridophosphate, Ba19P36O6+xN66-xCl8+x(x≈4.54), has been synthesized by heating a multicomponent reactant mixture consisting of phosphoryl triamide OP(NH2)3, thiophosphoryl triamide SP(NH2)3, BaS, and NH4Cl enclosed in an evacuated and sealed silica glass ampule up to 750°C. Despite the presence of side phases, the crystal structure was elucidated ab initio from high-resolution synchrotron powder diffraction data (λ=39.998 pm) applying the charge flipping algorithm supported by independent symmetry information derived from electron diffraction (ED) and scanning transmission electron microscopy (STEM). The compound crystallizes in the cubic space group Fm3c (no. 226) with a = 2685.41(3) pm and Z = 8. As confirmed by Rietveld refinement, the structure comprises all-side vertex sharing P(O,N)4 tetrahedra forming slightly distorted 3846812 cages representing a novel composite building unit (CBU). Interlinked through their 4-rings and additional 3-rings, the cages build up a 3D network with a framework density FD = 14.87 T/1000 Å3 and a 3D 8-ring channel system. Ba2+ and Clˉ as extra-framework ions are located within the cages and channels of the framework. The structuralmodel is corroborated by 31P double-quantum(DQ) /single-quantum (SQ) and triple-quantum (TQ) /single-quantum (SQ) 2D correlation MAS NMR spectroscopy. According to 31P{1H} C-REDOR NMR measurements, the H content is less than one H atom per unit cell
Lattice dynamics and vibrational spectra of the orthorhombic, tetragonal and cubic phases of methylammonium lead iodide
The hybrid halide perovskite CH3NH3PbI3 exhibits a complex structural
behaviour, with successive transitions between orthorhombic, tetragonal and
cubic polymorphs at ca. 165 K and 327 K. Herein we report first-principles
lattice dynamics (phonon spectrum) for each phase of CH3NH3PbI3. The
equilibrium structures compare well to solutions of temperature-dependent
powder neutron diffraction. By following the normal modes we calculate infrared
and Raman intensities of the vibrations, and compare them to the measurement of
a single crystal where the Raman laser is controlled to avoid degradation of
the sample. Despite a clear separation in energy between low frequency modes
associated with the inorganic PbI3 network and high-frequency modes of the
organic CH3NH3+ cation, significant coupling between them is found, which
emphasises the interplay between molecular orientation and the corner-sharing
octahedral networks in the structural transformations. Soft modes are found at
the boundary of the Brillouin zone of the cubic phase, consistent with
displacive instabilities and anharmonicity involving tilting of the PbI6
octahedra around room temperature.Comment: 9 pages, 4 figure
3D integrated superconducting qubits
As the field of superconducting quantum computing advances from the few-qubit
stage to larger-scale processors, qubit addressability and extensibility will
necessitate the use of 3D integration and packaging. While 3D integration is
well-developed for commercial electronics, relatively little work has been
performed to determine its compatibility with high-coherence solid-state
qubits. Of particular concern, qubit coherence times can be suppressed by the
requisite processing steps and close proximity of another chip. In this work,
we use a flip-chip process to bond a chip with superconducting flux qubits to
another chip containing structures for qubit readout and control. We
demonstrate that high qubit coherence (, s) is
maintained in a flip-chip geometry in the presence of galvanic, capacitive, and
inductive coupling between the chips
MON-380 Tinnitus with Unexpected Spanish Roots: Head and Neck Paragangliomas Caused by SDHAF2 Mutation
Introduction: Head and neck paragangliomas (HNPGL) are a subtype of pheochromocytoma/paraganglioma (Pheo/PGL) that originate from the autonomuos nervous system. In contrast to abdominal and thoracic Pheo/PGL, HNPGL are usually non-secretory, of parasympathetic origin and metastasize only rarely. Although HNPGL may occur as sporadic tumors, it is estimated that up to 40% of all cases may have a hereditary background that impacts therapeutic strategies, follow-up of affected patients and diagnostic approaches of family members. The most common mutations are found in the succinate dehydrogenase (SDH) genes with the highest prevalence of mutations in SDH-D, followed by SDH-B and SDH-C. Clinical case: A 15 year old male patient presented with tinnitus and hearing loss of the left ear. Imaging revealed a left sided jugulotympanic tumor (33x34mm) and a tumor of the right carotid body (12x15mm). The patient was normotensive, did not report on spells and plasma free metanephrine/catecholamine were not elevated. The morphological suspicion of a paraganglioma was confirmed histologically following resection of the jugulotympanic lesion. Immunohistochemistry showed a loss of SDHB-expression and genetic testing (somatic and germline) revealed a mutation in the SDH assembly factor 2 (SDHAF2) gene (c.232G>A). The patient's father is of Spanish descent. There was no family history for tumors. The hereditary paraglioma syndrome 2 (PGL2) has first been described in 1982 in a Dutch and later in a Spanish family and was found to be caused by a mutation in the SDHAF2 gene. SDHAF2 is a highly conserved co-factor involved in the flavination of the SDH-A subunit. The inheritence is autosomal dominant with maternal imprinting, leading to tumorigenesis only by paternal transmission. This may explain the seemingly negative family history. As in our case, patients with PGL2 usually present at young age with multiple, benign and non-secretory HNPGL. The penetrance reaches 88-100% by the age of 50 years. Conclusion: Our findings emphasize the relevance of genetic testing in patients with HNPGL, also with negative family history, especially when the patients present at young age and with multiple lesions
Neutrophils orchestrate post-myocardial infarction healing by polarizing macrophages towards a reparative phenotype
Aims Acute myocardial infarction (MI) is the leading cause of mortality worldwide. Anti-inflammatory strategies to reduce neutrophil-driven acute post-MI injury have been shown to limit acute cardiac tissue damage. On the other hand, whether neutrophils are required for resolving post-MI inflammation and repair is unknown. Methods and results We show that neutrophil-depleted mice subjected to MI had worsened cardiac function, increased fibrosis, and progressively developed heart failure. Flow cytometry of blood, lymphoid organs and digested hearts revealed reduced numbers of Ly6C(high) monocytes in infarcts of neutrophil-depleted mice, whereas the number of macrophages increased, which was paralleled by reduced splenic Ly6C(high) monocyte mobilization but enhanced proliferation of cardiac macrophages. Macrophage subtype analysis revealed reduced cardiac expression of M1 markers, whereas M2 markers were increased in neutrophil-depleted mice. Surprisingly, we found reduced expression of phagocytosis receptor myeloid-epithelial-reproductive tyrosine kinase, a marker of reparative M2c macrophages which mediate clearance of apoptotic cells. In agreement with this finding, neutrophil-depleted mice had increased numbers of TUNEL-positive cells within infarcts. We identified neutrophil gelatinase-associated lipocalin (NGAL) in the neutrophil secretome as a key inducer of macrophages with high capacity to engulf apoptotic cells. The cardiac macrophage phenotype in neutrophil-depleted mice was restored by administration of neutrophil secretome or NGAL. Conclusion Neutrophils are crucially involved in cardiac repair after MI by polarizing macrophages towards a reparative phenotype. Therapeutic strategies to reduce acute neutrophil-driven inflammation after MI should be carefully balanced as they might interfere with the healing response and cardiac remodelling
CARDIAC-TARGETED AAV-S100A1 HEART FAILURE GENE THERAPY: TRANSLATION OF A NOVEL MOLECULAR TARGET TOWARDS CLINICAL CARE
Inconsistent boundaries
Research on this paper was supported by a grant from the Marsden Fund, Royal Society of New Zealand.Mereotopology is a theory of connected parts. The existence of boundaries, as parts of everyday objects, is basic to any such theory; but in classical mereotopology, there is a problem: if boundaries exist, then either distinct entities cannot be in contact, or else space is not topologically connected (Varzi in Noûs 31:26–58, 1997). In this paper we urge that this problem can be met with a paraconsistent mereotopology, and sketch the details of one such approach. The resulting theory focuses attention on the role of empty parts, in delivering a balanced and bounded metaphysics of naive space.PostprintPeer reviewe
Multi-product inventory managmement model with a multiple periodicity
Inventory management is of great interest to various spheres of activity. This theory is a new industry that arose in connection with the need of optimal regulation of reserves. Over the past decades, significant progress has been made in the development of various mathematical models for managing commodity and noncommodity inventories. Despite the fact that this topic is quite popular in the literature, the question of purchasing resources in conditions of their deficit remains topical. The study is devoted to the development of a multi-product inventory management model with a multiple periodicity
Coherent Coupled Qubits for Quantum Annealing
Quantum annealing is an optimization technique which potentially leverages quantum tunneling to enhance computational performance. Existing quantum annealers use superconducting flux qubits with short coherence times limited primarily by the use of large persistent currents I[subscript p]. Here, we examine an alternative approach using qubits with smaller I[subscript p] and longer coherence times. We demonstrate tunable coupling, a basic building block for quantum annealing, between two flux qubits with small (approximately 50-nA) persistent currents. Furthermore, we characterize qubit coherence as a function of coupler setting and investigate the effect of flux noise in the coupler loop on qubit coherence. Our results provide insight into the available design space for next-generation quantum annealers with improved coherence.United States. Office of the Director of National IntelligenceUnited States. Intelligence Advanced Research Projects ActivityUnited States. Dept. of Defense. Assistant Secretary of Defense for Research & Engineering (FA8721-05-C-0002
- …