Synthesis and chiroptical property of C2-symmetric cyclohexapyrrole

Condensation reaction of gem-dimethyldipyrrylmethane-5,5′-dicarbinol and 4,4′-dimethyl-3,3′-di-iso-butyl-2,2′-bipyrrole under the catalysis by trifluoroacetic acid gave a hexapyrrolic macrocycle 6 in 15% yield after DDQ oxidation. X-ray crystallography of 6 shows that three parts of highly planar dipyrrylmethene unit are assembled by two sp³ hybridized gem-dimethyl carbon bridges and one direct linking at the pyrrole α-positions, leading to C₂ molecular symmetry. The complexation of 6 with (S)-(+)- and (R)-(−)-mandelic acid induced a CD Cotton effect at 461 and 650 nm.     

Relationship between Perceived Leg Length Discrepancy at One Month and Preoperative Hip Abductor Muscle Elasticity in Patients after Total Hip Arthroplasty

Objective: Preoperative factors related to perceived leg length discrepancy (PLLD) after total hip arthroplasty (THA) are not well studied. This study aimed to examine the preoperative factors, including hip abductor modulus, related to PLLD one month after THA. Methods: The study included 73 patients diagnosed with osteoarthritis secondary to developmental dysplasia of the hip and a posterior approach to surgery. Multiple logistic regression analysis was performed using the presence or absence of PLLD as the dependent variable and preoperative hip abductor''s modulus of elasticity, pain, hip abduction range of motion, hip abductor muscle strength and pelvic obliquity as the independent variable. Additionally, receiver operating characteristic curves were used for the extracted variables for calculating the cutoffs, sensitivity, specificity and area under the curve (AUC) to determine the presence or absence of PLLD. The significance level was set at p<0.05. Results: The hip abductor modulus (odds ratio=1.13; 95% confidence interval=1.06-1.21; p<0.001) was selected as a preoperative factor. The cutoff value to determine the presence or absence of a PLLD was 16.32 kPa. The sensitivity and specificity were 81.8% and 72.5%, respectively, and the AUC was 0.8137. Conclusion: The hip abductor muscle elastic modulus affected PLLD one month after THA. If the preoperative hip abductor elastic modulus is higher than the cutoff value, it may affect the appearance of PLLD at one month postoperatively.     

Squamin-A, Novel Cyclopeptide from Annona squamosa

Recentlyanumberofcyclopeptideswithuniquestructureswerereportedfromhigherplants"',especiallyfromAnnonasquamosaLinn.3'4.DuringourstudyonthechemicalconstituentsoftheseedsofAnnonasquamosaLinn.,anovelcyclopeptidenamedsquamin-Awasisolated.Inthisletterwereportthestructureofsquamin-A.Thewellpowdereddriedseeds(2.skg)ofAnnonasquamosaweredegreasedbypetroleumetherandpercolatedby95%EtOH.TheEtOHextractiwerepartitionedbetweenCHCI,andwaterandthechloroformsolubleportionwasseparatedbyrepeatedsilicagelcol…     

Vertex corrections to the anomalous Hall effect in spin-polarized two-dimensional electron gases with a Rashba spin-orbit interaction

We study the effect of disorder on the intrinsic anomalous Hall conductivity in a magnetic two-dimensional electron gas with a Rashba-type spin-orbit interaction. We find that anomalous Hall conductivity vanishes unless the lifetime is spin-dependent, similar to the spin Hall conductivity in the nonmagnetic system. In addition, we find that the spin Hall conductivity does not vanish in the presence of magnetic scatterers.     

Dynamics of a domain wall and spin-wave excitations driven by a mesoscopic current

The dynamics of a domain wall driven by a spin-polarized current in a mesoscopic system is studied numerically. Spin mixing in the states of the conduction electrons is fully taken into account. When the Fermi energy of the electrons is larger than the exchange energy (E(F) > J(sd)), the spin precession induces spin-wave excitations in the local spins which contribute towards the displacement of the domain wall. The resulting average velocity is found to be much smaller than the one obtained in the adiabatic limit. For E(F) < J(sd), the results are consistent with the adiabatic approximation except for the region below the critical current where a residual domain wall velocity is found.     

Magnetic properties of diluted magnetic semiconductors: Quantum Monte Carlo approach

The magnetic correlation between magnetic impurities in semiconductors is investigated by performing the quantum Monte Carlo (QMC) simulation. The Anderson Hamiltonian with the realistic parameters obtained by the local density approximation (LDA) calculation is employed. The LDA calculation gives a dispersion of the host (GaAs) electron and the mixing energy between host and magnetic impurity (Mn). The mixing between host and impurity electrons generates the impurity bound state in the energy gap of semiconductors. The long range ferromagnetic coupling is observed when the Fermi energy locates between the band edge and the impurity bound state. The ferromagnetic coupling is enhanced by decreasing temperature.     

稀土复合弹性材料的抗热氧化作用

利用稀土醇盐与ＰＳＢＲ橡胶乳液进行反应获得含稀土复合弹性材料进行抗热氧化研究,发现这种复弹性在热氧化后力学性能的保持率比参照样品有明显的提高,热重量试验表明含稀土复合弹性材料的热分解温度大幅度上升,经过氧化机制,认为抗热氧化效率的原因主要是稀土元素具有中止自动化链式反应的作用以及形成的络合结构有阻碍氧化的立体效应。     

Charge transport in the normal metal/diffusive ferromagnet/s-wave superconductor junctions

Charge transport in the normal metal/insulator/diffusive ferromagnet/insulator/s-wave superconductor (N/I/DF/I/S) junctions is studied for various situations solving the Usadel equation under the Nazarov's generalized boundary condition. Conductance of the junction is calculated by changing the magnitude of the resistance in DF, Thouless energy in DF, the exchange field in DF, the transparencies of the insulating barriers. We have found a new broad peak around zero voltage as well as zero bias conductance peak splitting and dip splitting.