Additional file 1 of Interpersonal predictors of loneliness in Japanese children: variable- and person-centered approaches

Additional file 1: Appendix 1. Syntax for mover-stayer LTA in Mplus

Preparation and Photophysical and Photoelectrochemical Properties of Supramolecular Porphyrin Nanorods Structurally Controlled by Encapsulated Fullerene Derivatives

A new class of porphyrin nanorods structurally controlled by encapsulated fullerene derivatives is prepared via a solvent mixture technique. These nanorods, composed of fullerenes (C60, C60 derivatives and C70) and zinc meso-tetra(4-pyridyl)porphyrin [ZnP(Py)4], are formed with the aid of a surfactant, cetyltrimethylammonium bromide (CTAB), in a DMF/acetonitrile mixture. In scanning electron microscopy (SEM) measurement, ZnP(Py)4 pristine hexagonal nanotubes with a large hollow structure [denoted as ZnP(Py)4 tube] are observed, whereas the hollow hole is completely closed in the case of nanorods composed of fullerenes (C60 and C70) and ZnP(Py)4 [fullerene−ZnP(Py)4 rod]. In C60 derivative−ZnP(Py)4 rods, the distorted polygonal columnar structures with large diameter and length are formed, as compared to the hexagonal structures of C60−ZnP(Py)4 and C70−ZnP(Py)4 rods. X-ray diffraction (XRD) analyses also reveals that ZnP(Py)4 alignment in the nanorod is based on the stacked assemblies of ZnP(Py)4 coordinated hexagonal formations. Elemental analysis and titration experiment by absorption measurement were also performed to quantitatively check the relative molecular ratio between porphyrins and fullerenes. Steady-state and time-resolved fluorescence spectra show efficient fluorescence quenching, suggesting the forward electron-transfer process from the singlet excited state of ZnP(Py)4 to fullerenes. Moreover, the back electron-transfer processes are detected by nanosecond transient absorption measurements. The forward and back electron-transfer rate constants are largely dependent on the structures of the nanorods. To construct photoelectrochemical solar cells, fullerene−ZnP(Py)4 rods are deposited onto nanostructured SnO2 films (OTE/SnO2). Fullerene−ZnP(Py)4 rod-modified electrodes exhibited efficient light energy conversion properties, such as a power conversion efficiency (η) of 0.63% and an incident photon to current conversion efficiency (IPCE) of 35%, which are much larger than those of ZnP(Py)4 tube

Comprehensive Analysis of Drug Loading into Engineered Lipoprotein Nanoparticles toward Their Eye Drop Application

The drug loading capacity of an engineered lipoprotein (eLP1) and the colloidal stability of drug-loaded eLP1s were assessed with 12 drugs with different charges/hydrophobicities. The capacity was largely correlated with their log P values, and the binding to the protein moiety was suggested for two drugs. The size of drug-loaded eLP1 formulations after freeze-drying followed by resolubilization hardly changed. The eLP1 formulation of travoprost, a clinically used drug in eye drop formulations, maintained its small size (19 nm) for 1 h at 37 °C in an artificial tear solution, whereas the liposome counterpart of 112 nm in diameter aggregated

Solubilization of Single-Wall Carbon Nanohorns Using a PEG−Doxorubicin Conjugate

A procedure for dispersing oxidized single-wall carbon nanohorns (oxSWNHs) in aqueous solution using a polyethylene glycol−doxorubicin (PEG−DXR) conjugate is described. In this procedure, oxSWNHs were first incubated with PEG−DXR in dimethyl sulfoxide (DMSO) or N,N-dimethylformamide (DMF), two organic solvents with relatively high electric dipole moments, after which the solvent was gradually changed to an aqueous one via addition of water until the final concentration of DMSO or DMF reached 10%. The PEG−DXR−oxSWNH complex that was obtained was able to pass through dextran-based chromatographic media (Sephadex G25) equilibrated with water. By contrast, untreated oxSWNHs and DXR-treated or PEG-treated oxSWNHs were unable to penetrate the column, indicating that the PEG−DXR conjugate endowed oxSWNHs with dispersibility in aqueous solution. In gel filtration experiments, the presence of free DXR had an inhibitory effect on the penetrability of PEG−DXR−oxSWNH complexes, which is consistent with the idea that PEG−DXR interacts with the surfaces of oxSWNHs via its DXR moiety. Quantitative analyses showed that the complex contained more than 250 mg of PEG−DXR for each gram of oxSWNHs. The average diameter of the dispersed complex was estimated to be approximately 160 nm using dynamic light scattering analysis. These results suggest that our method has the potential to open the way for the use of oxSWNHs as a clinically practical drug carrier. Keywords: Nanomedicine; carbon nanohorns; drug delivery systems; dispersion; anticancer agent; biocompatibilit

Urea-Assisted Reconstitution of Discoidal High-Density Lipoprotein

High-density lipoprotein (HDL) is a naturally occurring composite of lipids and lipid-binding proteins. The cholate dialysis method, first reported by Jonas in 1969, is the most widely used approach for reconstituting discoidal HDL (dHDL) in test tubes with phospholipids and the most dominant protein, apolipoprotein A-1 (apoA-I). Here, we show that a dHDL-relevant complex can also be prepared by gently mixing 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and apoA-I or its mutants in ethanol/H2O solutions containing urea at a concentration of a few molar and then incubating the mixture at the gel–liquid crystalline phase transition temperature in test tubes. Subsequent purification steps involve quick dialysis following size exclusion chromatography. The yields (73 ± 3% and 70 ± 1% protein and DMPC, respectively) of the resulting HDL-like nanoparticles, designated as uHDL, were comparable to the values of 68 ± 9% and 71 ± 12% obtained in the cholate dialysis method. Using apoA-I and two mutants, the key factor in this method was found to be urea at the folded and unfolded transition midpoint concentration. By using this urea-assisted method in the presence of a hydrophobic drug, all-trans-retinoic acid (ATRA), one-step preparation of ATRA-loaded uHDL was also possible. The loading efficiency was comparable to that in the mixing of ATRA and uHDL or dHDL reconstituted by the cholate dialysis method. Atomic force microscopy analysis revealed that uHDL and ATRA-loaded uHDL were discoidal. Our urea-assisted method is an easy and efficient method for reconstituting dHDL and can be utilized to prepare various drug–dHDL complexes

Selective Protein Separation Using Siliceous Materials with a Trimethoxysilane-Containing Glycopolymer

A copolymer with α-d-mannose (Man) and trimethoxysilane (TMS) units was synthesized for immobilization on siliceous matrices such as a sensor cell and membrane. Immobilization of the trimethoxysilane-containing copolymer on the matrices was readily performed by incubation at high heat. The recognition of lectin by poly­(Man-r-TMS) was evaluated by measurement with a quartz crystal microbalance (QCM) and adsorption on an affinity membrane, QCM results showed that the mannose-binding protein, concanavalin A, was specifically bound on a poly­(Man-r-TMS)-immobilized cell with a higher binding constant than bovine serum albumin. The amount of concanavalin A adsorbed during permeation through a poly­(Man-r-TMS)-immobilized membrane was higher than that through an unmodified membrane. Moreover, the concanavalin A adsorbed onto the poly­(Man-r-TMS)-immobilized membrane was recoverable by permeation of a mannose derivative at high concentration

Inhibition of Bacterial Adhesion on Hydroxyapatite Model Teeth by Surface Modification with PEGMA-Phosmer Copolymers

Modification of the interface properties on hydroxyapatite and tooth enamel surfaces was investigated to fabricate bacterial resistance <i>in situ</i>. A series of copolymers containing pendants of poly­(ethylene glycol) methyl ether methacrylate (PEGMA) and ethylene glycol methacrylate phosphate (Phosmer) were polymerized by conventional free radical polymerization and changing the feed ratio of monomers. The copolymers were immobilized on hydroxyapatite and tooth enamel via the affinity of phosphate groups to hydroxyapatite to form the stable and durable polymer brushes on the surfaces. The amounts of polymer immobilized depended on the phosphate group ratio in the copolymers. Surface modification altered the interfacial properties of hydroxyapatite and inhibited bacterial adhesion. Copolymers containing 40–60% PEGMA segments showed a significant inhibitory effect on bacterial adhesion of <i>S. epidermidis</i> both in the presence and absence of plaque model biomacromolecules

Bacterial Inhibition and Osteoblast Adhesion on Ti Alloy Surfaces Modified by Poly(PEGMA‑<i>r</i>‑Phosmer) Coating

We have synthesized and immobilized PEGMA₅₀₀-Phosmer to Ti6Al4V surfaces by a simple procedure to reduce bacteria-associated infection without degrading the cell response. Adhered bacteria coverage was lessened to 1% on polymer-coated surfaces when exposed to Escherichia coli, Staphylococcus epidermidis, and Streptococcus mutans. Moreover, PEGMA₅₀₀-Phosmer and homoPhosmer coatings presented better responses to MC3T3-E1 preosteoblast cells when compared with the results for PEGMA₂₀₀₀-Phosmer-coated and raw Ti alloy surfaces. The behavior of balancing bacterial inhibition and cell attraction of the PEGMA₅₀₀-Phosmer coating was explained by the grafted phosphate groups, with an appropriate PEG brush length facilitating greater levels of calcium deposition and further fibronectin adsorption when compared with that of the raw Ti alloy surface

Surface Modification of Siliceous Materials Using Maleimidation and Various Functional Polymers Synthesized by Reversible Addition–Fragmentation Chain Transfer Polymerization

A novel surface modification method was investigated. The surface of siliceous materials was modified using polystyrene, poly­(acrylic acid), poly­(<i>N</i>-isopropylacrylamide), and poly­(<i>p</i>-acrylamidophenyl-α-mannoside) synthesized by reversible addition–fragmentation chain transfer polymerization. Thiol-terminated polymers were obtained by reduction of the thiocarbonate group using sodium borohydride. The polymers were immobilized on the surface via the thiol–ene click reaction, known as the Michael addition reaction. Immobilization of the polymers on the maleimidated surface was confirmed by X-ray photoelectron spectroscopy, infrared spectroscopy, and contact angle measurements. The polymer-immobilized surfaces were observed by atomic force microscopy, and the thickness of the polymer layers was determined by ellipsometry. The thickness of the polymer immobilized by the maleimide–thiol reaction was less than that formed by spin coating, except for polystyrene. Moreover, the polymer-immobilized surfaces were relatively smooth with a roughness of less than 1 nm. The amounts of amine, maleimide, and polymer immobilized on the surface were determined by quartz crystal microbalance measurements. The area occupied by the amine-containing silane coupling reagent was significantly less than the theoretical value, suggesting that a multilayer of the silane coupling reagent was formed on the surface. The polymer with low molecular weight had the tendency to efficiently immobilize on the maleimidated surface. When poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-immobilized surfaces were used as a platform for protein microarrays, strong interactions were detected with the mannose-binding lectin concanavalin A. The specificity of poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-immobilized surfaces for concanavalin A was compared with poly-l-lysine-coated surfaces. The poly-l-lysine-coated surfaces nonspecifically adsorbed both concanavalin A and bovine serum albumin, while the poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-immobilized surface preferentially adsorbed concanavalin A. Moreover, the poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-immobilized surface was applied to micropatterning with photolithography. When the micropattern was formed on the poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-spin-coated surface by irradiation with ultraviolet light, the pattern of the masking design was not observed on the surface adsorbed with fluorophore-labeled concanavalin A using a fluorescent microscope because of elution of poly­(<i>p</i>-acrylamidophenyl-α-mannoside) from the surface. In contrast, fluorophore-labeled concanavalin A was only adsorbed on the shaded region of the poly­(<i>p</i>-acrylamidophenyl-α-mannoside)-immobilized surface, resulting in a distinctive fluorescent pattern. The surface modification method using maleimidation and reversible addition–fragmentation chain transfer polymerization can be used for preparing platforms for microarrays and micropatterning of proteins

Effects of the Arrangement of a Distal Catalytic Residue on Regioselectivity and Reactivity in the Coupled Oxidation of Sperm Whale Myoglobin Mutants

The coupled oxidations of sperm whale myoglobin (Mb) mutants are performed to examine active site residues controlling the regiospecific heme degradation. HPLC analysis of biliverdin isomers shows that L29H/H64L Mb almost exclusively gives biliverdin IXγ, although H64L and wild-type Mb mainly afford the α-isomer. Relocation of the distal histidine at the 43 and 107 positions increases the amount of γ-isomer to 44 and 22%, respectively. Interestingly, the increase in the ratio of γ-isomer is also observed by a single replacement of either His-64 with Asp or Phe-43 with Trp. It appears that the polarity of the active site as well as hydrogen bonding between oxygen molecule bound to the heme iron and His or Trp is important in controlling the regioselectivity. The results of coupled oxidation kinetics, autoxidation kinetics, and redox potential of the Fe3+/Fe2+ couple are discussed with regard to their implications for the active site and mechanism of heme oxygenase