Synthesis of high-performance nickel hydroxide nanosheets/gadolinium doped-α-MnO2 composite nanorods as cathode and Fe3O4/GO nanospheres as anode for an all-solid-state asymmetric supercapacitor

The wide use of manganese dioxide(MnO₂)as an electrode in all-solid-state asymmetric supercapacitors(ASCs)remains challenging because of its low electrical conductivity.This complication can be circumvented by introducing trivalent gadolinium(Gd)ions into the MnO₂.Herein,we describe the successful hydrothermal synthesis of crystalline Gd-doped MnO₂ nanorods with Ni(OH)₂ nanosheets as cathode,which we combined with Fe₃O₄/GO nanospheres as anode for all-solid-state ASCs.Electrochemical tests dem on strate that Gd dopi ng sign ifica ntly affected the electrochemical activities of the MnO₂,which was further enhanced by introducing Ni(OH)₂.The GdMnO₂/Ni(OH)₂ electrode offers sufficient surface electrochemical activity and exhibits excellent specific capacity of 121.8 mA h g^-1,at 1A g^-1,appealing rate performance,and ultralong lifetime stability(99.3%retention after 10,000 discharge tests).Furthermore,the GdMnO₂/Ni(OH)₂//PVA/KOH//Fe₃O₄/GO solid-state ASC device offers an impressive specific energy density(60.25 W h kg^-1)at a high power density(2332 W kg^-1).This investigation thus shows its large potential in developing novel approaches to energy storage devices.     

Bis­(azido‐κN)[(6R,7S,8S,14S)‐(–)‐sparteine‐κ2N,N′]copper(II)

In the title compound, [Cu(N₃)₂(C₁₅H₂₆N₂)], the chiral alkaloid (−)‐l‐sparteine (Sp) acts as a bidentate ligand, with two azide ligands occupying the remaining coordination sites, forming a distorted CuN₄ tetrahedron. The dihedral angle between the N_Sp—Cu—N_Sp and N_azide—Cu—N_azide planes is 55.3 (2)°. Principal dimensions include Cu—N_Sp = 2.011 (6) and 2.025 (5) Å, and Cu—N_azide = 1.939 (6) and 1.934 (7) Å. The mid‐point of the N_Sp⋯N_Sp line does not lie exactly in the N_azide—Cu—N_azide plane, but is tilted towards one of the N_Sp atoms by 0.026 Å.     

Gelatin Coating for the Improvement of Stability and Cell Uptake of Hydrophobic Drug-Containing Liposomes

Purpose: Most therapeutic agents have limitations owing to low selectivity and poor solubility, resulting in post-treatment side effects. Therefore, there is a need to improve solubility and develop new formulations to deliver therapeutic agents specifically to the target site. Gelatin is a natural protein that is composed of several amino acids. Previous studies revealed that gelatin contains arginyl-glycyl-aspartic acid (RGD) sequences that become ligands for the integrin receptors expressed on cancer cells. Thus, in this study, we aimed to increase the efficiency of drug delivery into cancer cells by coating drug-encapsulating liposomes with gelatin (gelatin-coated liposomes, GCLs). Methods: Liposomes were coated with gelatin using electrostatic interaction and covalent bonding. GCLs were compared with PEGylated liposomes in terms of their size, zeta potential, encapsulation efficiency, stability, dissolution profile, and cell uptake. Results: Small-sized and physically stable GCLs were prepared, and they showed high drug-encapsulation efficiency. An in vitro dissolution study showed sustained release depending on the degree of gelatin coating. Cell uptake studies showed that GCLs were superior to PEGylated liposomes in terms of cancer cell-targeting ability. Conclusions: GCLs can be a novel and promising carrier system for targeted anticancer agent delivery. GCLs, which exhibited various characteristics depending on the coating degree, could be utilized in various ways in future studies.     

CRFalign: A Sequence-Structure Alignment of Proteins Based on a Combination of HMM-HMM Comparison and Conditional Random Fields

Sequence–structure alignment for protein sequences is an important task for the template-based modeling of 3D structures of proteins. Building a reliable sequence–structure alignment is a challenging problem, especially for remote homologue target proteins. We built a method of sequence–structure alignment called CRFalign, which improves upon a base alignment model based on HMM-HMM comparison by employing pairwise conditional random fields in combination with nonlinear scoring functions of structural and sequence features. Nonlinear scoring part is implemented by a set of gradient boosted regression trees. In addition to sequence profile features, various position-dependent structural features are employed including secondary structures and solvent accessibilities. Training is performed on reference alignments at superfamily levels or twilight zone chosen from the SABmark benchmark set. We found that CRFalign method produces relative improvement in terms of average alignment accuracies for validation sets of SABmark benchmark. We also tested CRFalign on 51 sequence–structure pairs involving 15 FM target domains of CASP14, where we could see that CRFalign leads to an improvement in average modeling accuracies in these hard targets (TM-CRFalign ≃42.94%) compared with that of HHalign (TM-HHalign ≃39.05%) and also that of MRFalign (TM-MRFalign ≃36.93%). CRFalign was incorporated to our template search framework called CRFpred and was tested for a random target set of 300 target proteins consisting of Easy, Medium and Hard sets which showed a reasonable template search performance.     

Analytic Description of Layer Undulations in Smectic A Liquid Crystals

We investigate the layer undulations that appear in smectic A liquid crystals when a magnetic field is applied in the direction parallel to the smectic layers. In an earlier work (García-Cervera and Joo in J Comput Theor Nanosci 7:795–801, 2010) the authors characterized the critical field using the Landau–de Gennes model for smectic A liquid crystals. In this paper, we obtain an asymptotic expression of the unstable modes using Γ-convergence theory, and a sharp estimate of the critical field. Under the assumption that the layers are fixed at the boundaries, the maximum layer undulation occurs in the middle of the cell and the displacement amplitude decreases near the boundaries. Our estimate of the critical field is consistent with the Helfrich–Hurault theory. When natural boundary conditions are considered, the displacement amplitude does not diminish near the boundary, in sharp contrast with the Dirichlet case, and the critical field is reduced compared to the one calculated in the classical theory. This is consistent with the experiments carried out by Ishikawa and Lavrentovich (Phys Rev E 63:030501(R), 2001). Furthermore, we prove the existence and stability of the solution to the nonlinear system of the Landau–de Gennes model using bifurcation theory. Numerical simulations are used to illustrate the predictions of the analysis.     

Effects of poloxamer on the gelation of silk sericin

Effects of the concentration of poloxamer 407, temperature, and the concentration of sericin on the gelation of silk sericin (SS) were studied. Gelation of SS was accelerated with an increase in poloxamer concentration and temperature. The sol‐gel transition of SS became irreversible with respect to the temperature in the presence of poloxamer, whereas the sol‐gel transition of SS itself was reversible. Infrared (IR) and circular dichroism (CD) spectra show that the conformational change of SS in the presence of poloxamer was accelerated from random coil to β‐structure. X‐ray diffraction and differential scanning calorimetry (DSC) show that the crystalline structure of poloxamer in the mixture was affected by the presence of SS and that its melting temperature was shifted to lower temperature with increasing SS content, indicating an interaction between poloxamer and SS through hydrogen and hydrophobic bondings.     

Scheduling preventive maintenance for modular designed components: A dynamic approach

One of the benefits of modular design is ease-of-service. While modular design helps simplify field maintenance, extensive depot maintenance and spare modules are required to support the field maintenance. This study develops a dynamic approach for scheduling preventive maintenance at a depot with the limited availability of spare modules and other constraints. A backward allocation algorithm is proposed and applied to scheduling the preventive maintenance of an engine module installed in T-59 advanced jet trainers in the Republic of Korea Air Force. The algorithm developed by this study can be used to solve similar problems for various systems such as aerospace vehicles, heavy machinery, and medical equipment. The contribution of this study includes the uniqueness of the algorithm, the flexibility to deal with variables changing over time, and the ability to incorporate additional variables to handle complex situations.     

A Coburn type theorem for Toeplitz operators on the Dirichlet space

A celebrated theorem of Coburn asserts that, on the setting of the Hardy space, if a Toeplitz operator is nonzero, then either it is one-to-one or its adjoint operator is one-to-one. In this paper, we show that an analogous result holds for Toeplitz operators acting on the Dirichlet space.     

Queue length and waiting time of the M/G/1 queue under the D-policy and multiple vacations

We study the steady-state queue length and waiting time of the M/G/1 queue under the D-policy and multiple server vacations. We derive the queue length PGF and the LSTs of the workload and waiting time. Then, the mean performance measures are derived. Finally, a numerical example is presented and the effects of employing the D-policy are discussed. AMS Subject Classifications 60K25 This work was supported by the SRC/ERC program of MOST/KOSEF grant # R11-2000-073-00000.