5,976 research outputs found
catena-Poly[[tris[silver(I)-μ-4,4′-bipyridine-κ2 N:N′]] tris(perchlorate) dihydrate]
In the title compound, {[Ag3(C10H8N2)3](ClO4)3·2H2O}n, one of the AgI ions, one of the 4,4′-bipyridine (bipy) ligands and one of the perchlorate anions are each situated on a twofold rotation axis. Each AgI ion is coordinated by two N atoms from two bridging bipy ligands, forming chains along [101]. π–π interactions between the pyridine rings [centroid–centroid distances = 3.638 (8) and 3.688 (8) Å] connect the chains. Intermolecular O—H⋯O hydrogen bonds link the uncoordinated water molecules and the perchlorate anions
Bis(μ-3-chlorobenzene-1,2-dicarboxylato-κ2 O 2:O 2)bis[diaqua(5,5′-dimethyl-2,2′-bipyridine-κ2 N,N′)copper(II)]
In the centrosymmetric binuclear title compound, [Cu2(C8H3ClO4)2(C12H12N2)2(H2O)4], the CuII ion is six-coordinated by two N atoms from a 5,5′-dimethyl-2,2′-bipyridine ligand, two bridging O atoms from two 3-chlorobenzene-1,2-dicarboxylate ligands and two water molecules in a distorted octahedral geometry. The binuclear complex molecules are linked together by intermolecular O—H⋯O hydrogen bonds into a layer parallel to (100). The layers are connected by C—H⋯Cl hydrogen bonds. Intramolecular O—H⋯O hydrogen bonds and π–π interactions [centroid–centroid distance = 3.5958 (16) Å] are also present
Novel N,S-phenacyl protecting group and its application for peptide synthesis
The phenacyl group can be introduced onto amino and thio groups by N,S-alkylation reactions. Conversely, these groups are removed rapidly by employing magnesium in acetic acid. This protecting group was successfully applied to a short peptide synthesis of Boc-L-Cys-Gly-OMe
Benzyl 2,5-dioxopyrrolidin-1-yl carbonate
The asymmetric unit of the title compound, C12H11NO5, contains two independent molecules with similar geometric parameters but different orientations of the phenyl rings. The molecular packing is stabilized by weak nonclassical C—H⋯O hydrogen-bonding interactions
Observation of Majorana fermions with spin selective Andreev reflection in the vortex of topological superconductor
Majorana fermion (MF) whose antiparticle is itself has been predicted in
condensed matter systems. Signatures of the MFs have been reported as zero
energy modes in various systems. More definitive evidences are highly desired
to verify the existence of the MF. Very recently, theory has predicted MFs to
induce spin selective Andreev reflection (SSAR), a novel magnetic property
which can be used to detect the MFs. Here we report the first observation of
the SSAR from MFs inside vortices in Bi2Te3/NbSe2 hetero-structure, in which
topological superconductivity was previously established. By using
spin-polarized scanning tunneling microscopy/spectroscopy (STM/STS), we show
that the zero-bias peak of the tunneling differential conductance at the vortex
center is substantially higher when the tip polarization and the external
magnetic field are parallel than anti-parallel to each other. Such strong spin
dependence of the tunneling is absent away from the vortex center, or in a
conventional superconductor. The observed spin dependent tunneling effect is a
direct evidence for the SSAR from MFs, fully consistent with theoretical
analyses. Our work provides definitive evidences of MFs and will stimulate the
MFs research on their novel physical properties, hence a step towards their
statistics and application in quantum computing.Comment: 4 figures 15 page
Superconductivity Induced by Site-Selective Arsenic Doping in MoSi
Arsenic doping in silicides has been much less studied compared with
phosphorus. In this study, superconductivity is successfully induced by As
doping in MoSi. The superconducting transition temperature ()
reaches 7.7 K, which is higher than those in previously known WSi-type
superconductors. MoSiAs is a type-II BCS superconductor with upper and
lower critical fields of 6.65 T and 22.4 mT, respectively. In addition, As
atoms are found to selectively take the 8 sites in MoSiAs. The
emergence of superconductivity is possibly due to the shift of Fermi level as a
consequence of As doping, as revealed by the specific heat measurements and
first-principles calculations. Our work provides not only another example of As
doping, but also a practical strategy to achieve superconductivity in silicides
through Fermi level engineering.Comment: Supporting Information available at the corresponding DO
Strong-Coupling Superconductivity with 10.8 K Induced by P Doping in the Topological Semimetal MoSi
By performing P doping on the Si sites in the topological semimetal
MoSi, we discover strong-coupling superconductivity in
MoSiP (0.5 2.0). MoSi crystallizes in
the WSi-type structure with space group of (No. 140), and is
not a superconductor itself. Upon P doping, the lattice parameter decreases
while increases monotonously. Bulk superconductivity is revealed in
MoSiP (0.5 2.0) from resistivity,
magnetization, and heat capacity measurements. in
MoSiP reaches as high as 10.8 K, setting a new record among
the WSi-type superconductors. The upper and lower critical fields for
MoSiP are 14.56 T and 105 mT, respectively. Moreover,
MoSiP is found to be a fully gapped superconductor with
strong electron-phonon coupling. First-principles calculations suggest that the
enhancement of electron-phonon coupling is possibly due to the shift of the
Fermi level, which is induced by electron doping. The calculations also reveal
the nontrivial band topology in MoSi. The and upper critical
field in MoSiP are fairly high among pseudobinary compounds.
Both of them are higher than those in NbTi, making future applications
promising. Our results suggest that the WSi-type compounds are ideal
platforms to search for new superconductors. By examinations of their band
topologies, more candidates for topological superconductors can be expected in
this structural family.Comment: 15 pages, 5 figures. Supplementary Information availabe at the
corresponding DO
Targeting Gpr52 lowers mutant HTT levels and rescues Huntington's disease-associated phenotypes.
See Huang and Gitler (doi:10.1093/brain/awy112) for a scientific commentary on this article.Lowering the levels of disease-causing proteins is an attractive treatment strategy for neurodegenerative disorders, among which Huntington's disease is an appealing disease for testing this strategy because of its monogenetic nature. Huntington's disease is mainly caused by cytotoxicity of the mutant HTT protein with an expanded polyglutamine repeat tract. Lowering the soluble mutant HTT may reduce its downstream toxicity and provide potential treatment for Huntington's disease. This is hard to achieve by small-molecule compound drugs because of a lack of effective targets. Here we demonstrate Gpr52, an orphan G protein-coupled receptor, as a potential Huntington's disease drug target. Knocking-out Gpr52 significantly reduces mutant HTT levels in the striatum and rescues Huntington's disease-associated behavioural phenotypes in a knock-in Huntington's disease mouse model expressing endogenous mutant Htt. Importantly, a novel Gpr52 antagonist E7 reduces mutant HTT levels and rescues Huntington's disease-associated phenotypes in cellular and mouse models. Our study provides an entry point for Huntington's disease drug discovery by targeting Gpr52
Applications of machine learning in familial hypercholesterolemia
Familial hypercholesterolemia (FH) is a common hereditary cholesterol metabolic disease that usually leads to an increase in the level of low-density lipoprotein cholesterol in plasma and an increase in the risk of cardiovascular disease. The lack of disease screening and diagnosis often results in FH patients being unable to receive early intervention and treatment, which may mean early occurrence of cardiovascular disease. Thus, more requirements for FH identification and management have been proposed. Recently, machine learning (ML) has made great progress in the field of medicine, including many innovative applications in cardiovascular medicine. In this review, we discussed how ML can be used for FH screening, diagnosis and risk assessment based on different data sources, such as electronic health records, plasma lipid profiles and corneal radian images. In the future, research aimed at developing ML models with better performance and accuracy will continue to overcome the limitations of ML, provide better prediction, diagnosis and management tools for FH, and ultimately achieve the goal of early diagnosis and treatment of FH
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