Low-velocity anisotropic Dirac fermions on the side surface of topological insulators

We report anisotropic Dirac-cone surface bands on a side-surface geometry of the topological insulator Bi$_2$Se$_3$ revealed by first-principles density-functional calculations. We find that the electron velocity in the side-surface Dirac cone is anisotropically reduced from that in the (111)-surface Dirac cone, and the velocity is not in parallel with the wave vector {\bf k} except for {\bf k} in high-symmetry directions. The size of the electron spin depends on the direction of {\bf k} due to anisotropic variation of the noncollinearity of the electron state. Low-energy effective Hamiltonian is proposed for side-surface Dirac fermions, and its implications are presented including refractive transport phenomena occurring at the edges of tological insulators where different surfaces meet.Comment: 4 pages, 2 columns, 4 figure

The involvement of GSK3β for glycogen synthesis throughout the annual cycle of Pacific oyster, Crassostrea gigas (Magallana gigas)

Crassostrea gigas is a frequently studied species in understanding physiological processes in bivalves. Similar to other animals, oysters store glucose in the body as glycogen. Glycogen is known to supply energy for germ cell development and maintenance. Glycogen is synthesized by glycogen synthase. GSK3β regulates glycogen synthase activity and plays an important role in glycogen synthesis. Therefore, this study aims to examine the effect of GSK3β on the annual cycle of oysters and the glycogen synthesis pathway and to investigate the energy pathway in comparison with seasonal variation. Oysters were sampled monthly for one year and were subjected to glycogen content, RT-PCR, FISH, and western blot analysis. The year-round glycogen content significantly differs only in the mantle edge during spring and summer of both sexes but not in labial palp, digestive gland, gonad, and adductor muscle. The expression of GSK3β mRNA level was highest in October for females and April for males. Both sexes had the lowest expression in July. In the adductor muscle, females and males showed the highest expression in April and the lowest in July and October. The pattern of GSK3β expression in gonads and adductor muscle was similarly confirmed through FISH. As a result of examining the signaling system, p-GSK3β (serine 9) increased. At the same time, glycogen synthase decreased in May when the condition index was the highest, p-GSK3β decreased in October and July when spawning occurred, and glycogen synthase increased. Overall, it is thought that p-GSK3β expression is high in C. gigas at ripe, which inhibits glycogen synthesis and is used as energy for growth and maturation. Glycogen synthesis occurs for energy storage during degeneration

Role of Matrix Metalloproteinase 3-mediated alpha-Synuclein Cleavage in Dopaminergic Cell Death

Evidence suggests that the C-terminal truncation of alpha-synuclein is equally important as aggregation of alpha-synuclein in Parkinson disease (PD). Our previous results showed that an endopeptidase, matrix metalloproteinase-3 (MMP3), was induced and activated in dopaminergic (DA) cells upon stress conditions. Here, we report that MMP3 cleaved alpha-synuclein in vitro and in vivo and that alpha-synuclein and MMP3 were co-localized in Lewy bodies (LB) in the postmortem brains of PD patients. Incubation of alpha-synuclein with the catalytic domain of MMP3 (cMMP3) resulted in generation of several peptides, and the peptide profiles of WT alpha-synuclein (WTsyn) and A53T mutant (A53Tsyn) were different. Combined analysis using mass spectrometry and N-terminal determination revealed that MMP3 generated C-terminally truncated peptides of amino acids 1-78, 1-91, and 1-93 and that A53Tsyn produced significantly higher quantities of these peptides. Similar sizes of peptides were detected in N27 DA cells under oxidative stress and RNA interference to knock down MMP3-attenuated peptide generation. Co-overexpression of cMMP3 with either WTsyn or A53Tsyn led to a reduction in Triton X-100-insoluble aggregates and an increase in protofibril-like small aggregates. In addition, overexpression of the 1-93-amino acid peptide in the substantia nigra led to DA neuronal loss without LB-like aggregate formation. The results strongly indicate that MMP3 digestion of alpha-synuclein in DA neurons plays a pivotal role in the progression of PD through modulation of alpha-synuclein in aggregation, LB formation, and neurotoxicity

Half-metallic antiferromagnets in double perovskites: LaAVRuO6_6 (A=Ca, Sr, and Ba)

Based on the theoretical exploration of electronic structures, we propose that the ordered double perovskites LaAVRuO$_6$ and LaVO$_3$/ARuO$_3$ (001) superlattice (A = Ca, Sr and Ba) are strong candidates for half-metallic (HM) antiferromagnets (AFMs). %LaAVRuO$_6$ and LaVO$_3$/ARuO$_3$ have the %100% spin polarizations at the Fermi level but with zero %total magnetic moments. We have shown that the HM-AFM nature in LaAVRuO$_6$ is very robust regardless of (i) divalent ion replacement at A-sites, (ii) oxygen site relaxation, (iii) the inclusion of the Coulomb correlation, and (iv) cation disorder. A type of the double exchange interaction is expected to be responsible for the half-metallicity and the antiferromagnetism in these systems.Comment: 4 pages, 4 figure

Spin-orbit coupled molecular quantum magnetism realized in inorganic solid

Molecular quantum magnetism involving an isolated spin state is of particular interest due to the characteristic quantum phenomena underlying spin qubits or molecular spintronics for quantum information devices, as demonstrated in magnetic metal-organic molecular systems, the so-called molecular magnets. Here we report the molecular quantum magnetism realized in an inorganic solid Ba3Yb2Zn5O11 with spin-orbit coupled pseudospin-1/2 Yb3+ ions. The magnetization represents the magnetic quantum values of an isolated Yb-4 tetrahedron with a total (pseudo) spin 0, 1 and 2. Inelastic neutron scattering results reveal that a large Dzyaloshinsky-Moriya interaction originating from strong spin-orbit coupling of Yb 4f is a key ingredient to explain magnetic excitations of the molecular magnet states. The Dzyaloshinsky-Moriya interaction allows a non-adiabatic quantum transition between avoided crossing energy levels, and also results in unexpected magnetic behaviours in conventional molecular magnets.1141Ysciescopu

TonEBP suppresses IL-10-mediated immunomodulation

TonEBP is a key transcriptional activator of M1 phenotype in macrophage, and its high expression is associated with many inflammatory diseases. During the progression of the inflammatory responses, the M1 to M2 phenotypic switch enables the dual role of macrophages in controlling the initiation and resolution of inflammation. Here we report that in human and mouse M1 macrophages TonEBP suppresses IL-10 expression and M2 phenotype. TonEBP knockdown promoted the transcription of the IL-10 gene by enhancing chromatin accessibility and Sp1 recruitment to its promoter. The enhanced expression of M2 genes by TonEBP knockdown was abrogated by antagonism of IL-10 by either neutralizing antibodies or siRNA-mediated silencing. In addition, pharmacological suppression of TonEBP leads to similar upregulation of IL-10 and M2 genes. Thus, TonEBP suppresses M2 phenotype via downregulation of the IL-10 in M1 macrophagesope

Transcription factor NFAT5 promotes macrophage survival in rheumatoid arthritis

Defective apoptotic death of activated macrophages has been implicated in the pathogenesis of rheumatoid arthritis (RA). However, the molecular signatures defining apoptotic resistance of RA macrophages are not fully understood. Here, global transcriptome profiling of RA macrophages revealed that the osmoprotective transcription factor nuclear factor of activated T cells 5 (NFAT5) critically regulates diverse pathologic processes in synovial macrophages including the cell cycle, apoptosis, and proliferation. Transcriptomic analysis of NFAT5-deficient macrophages revealed the molecular networks defining cell survival and proliferation. Proinflammatory M1-polarizing stimuli and hypoxic conditions were responsible for enhanced NFAT5 expression in RA macrophages. An in vitro functional study demonstrated that NFAT5-deficient macrophages were more susceptible to apoptotic death. Specifically, CCL2 secretion in an NFAT5-dependent fashion bestowed apoptotic resistance to RA macrophages in vitro. Injection of recombinant CCL2 into one of the affected joints of Nfat5+/-mice increased joint destruction and macrophage infiltration, demonstrating the essential role of the NFAT5/CCL2 axis in arthritis progression in vivo. Moreover, after intra-articular injection, NFAT5-deficient macrophages were more susceptible to apoptosis and less efficient at promoting joint destruction than were NFAT5-sufficient macrophages. Thus, NFAT5 regulates macrophage survival by inducing CCL2 secretion. Our results provide evidence that NFAT5 expression in macrophages enhances chronic arthritis by conferring apoptotic resistance to activated macrophages.clos

Pharmacokinetic study of meropenem in healthy beagle dogs receiving intermittent hemodialysis

Meropenem, a second carbapenem antimicrobial agent with a broad spectrum of activity, is used to treat sepsis and resistant-bacterial infections in veterinary medicine. The objective of this study was to identify the pharmacokinetics of meropenem in dogs receiving intermittent hemodialysis (IHD) and to determine the proper dosing in renal failure patients receiving IHD. Five healthy beagle dogs were given a single i.v. dose of 24 mg/kg of meropenem and received IHD. The blood flow rate, dialysate flow, and ultrafiltration rate were maintained at 40 mL/min, 300 mL/min, and 40 mL/h, respectively. Blood samples were collected for 24 h from the jugular vein and from the extracorporeal arterial and venous line. Urine samples and dialysate were also collected. The concentrations of meropenem were assayed using HPLC/MS/MS determination. The peak plasma concentration was 116 +/- 37 mu g/mL at 15 min. The systemic clearance was 347 +/- 117 mL/h/kg, and the steady-state volume of distribution was 223 +/- 67 mL/kg. Dialysis clearance was 71.1 +/- 34.3 mL/h/kg, and the extraction ratio by hemodialysis was 0.455 +/- 0.150. The half-life (T-1/2) in dogs with IHD decreased compared with those without IHD, and the reduction in T1/2 was greater in renal failure patients than in normal patients. Sixty-nine percent and 21% of the administered drug were recovered by urine and dialysate in the unchanged form, respectively. In conclusion, additional dosing of 24 mg/kg of meropenem after dialysis could be necessary according to the residual renal function of the patient based on the simulated data.OAIID:RECH_ACHV_DSTSH_NO:T201621129RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A003050CITE_RATE:1.279FILENAME:Byun_et_al-2016-Journal_of_Veterinary_Pharmacology_and_Therapeutics.pdfDEPT_NM:수의학과EMAIL:[email protected]_YN:YFILEURL:https://srnd.snu.ac.kr/eXrepEIR/fws/file/eb2b2d93-6cb2-4420-a374-90eb43215957/linkCONFIRM: