Separation and quantification of monoclonal-antibody aggregates by hollow-fiber-flow field-flow fractionation

Hollow-fiber-flow field-flow fractionation (HF5) separates protein molecules on the basis of the difference in the diffusion coefficient, and can evaluate the aggregation ratio of proteins. However, HF5 is still a minor technique because information on the separation conditions is limited. We examined in detail the effect of different settings, including the main-flow rate, the cross-flow rate, the focus point, the injection amount, and the ionic strength of the mobile phase, on fractographic characteristics. On the basis of the results, we proposed optimized conditions of the HF5 method for quantification of monoclonal antibody in sample solutions. The HF5 method was qualified regarding the precision, accuracy, linearity of the main peak, and quantitation limit. In addition, the HF5 method was applied to non-heated Mab A and heat-induced-antibody-aggregate-containing samples to evaluate the aggregation ratio and the distribution extent. The separation performance was comparable with or better than that of conventional methods including analytical ultracentrifugation–sedimentation velocity and asymmetric-flow field-flow fractionation.     

Side‐chain effect of octa‐substituted POSS fillers on refraction in polymer composites

To investigate the relationship between the chemical structures of the side chains of polyoctahedral oligomeric silsesquioxanes (POSS) fillers and the ability to decrease the refractive indices of the polymer composites, we examined the influence on the degree of polymer chain packing by the existence of the octa‐substituted POSS derivatives. The polymer composites containing methyl‐, ethyl‐, vinyl‐, isobutyl‐, octyl‐, octadecyl‐, cyclopentyl‐, and phenyl‐substituted POSS in poly(methyl methacrylate) (PMMA) were prepared. The packing coefficients of the PMMA composites containing POSS derivatives were evaluated from molar refractions and refractive indices of the films with the Lorentz–Lorenz equation. We found that the ethyl group shows the lowest values of the packing coefficients and a significant effect in reducing the refractive indices of the polymer composites. Finally, in summary, it was shown that POSS molecules can intrinsically offer to reduce a packing. In addition, less entanglement and smaller interactions between polymer chains and the substitution groups are favorable to release a packing, resulting in decreases in refractive indices. Our findings described here are the first efforts to quantitatively evaluate the ability of POSS fillers to lower refractive indices at the molecular level. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Compaction characteristics for the towed and driven conditions of a wheel operating in an agricultural soil

High axle loads, duration of strain as well as strain rate due to applied stresses, and field moisture condition have been found to contribute to compaction in the field. Numerous previous investigations on agricultural soil compaction were carried out with relatively dry soil. The aim of this study was to investigate the interrelationships between compaction, applied load, vehicle speed and a certain practical range of soil moisture content through a soil bin investigation of the compaction which results from the passage of a towed and a driven wheel. Soil pressure and the corresponding bulk density were analysed using a model proposed by Bailey et al. (J. agric Engng Res. 33, 257–262 (1986)) and ANOVA techniques. The results showed that compaction was higher at the higher moisture content level for both towed and driven conditions of the wheel, and that it was applied load that had the greatest contributory effect. Also, compaction was higher in the case of the driven wheel as compared to the towed wheel due to the phenomenon of slip sinkage. Bailey's model, it appears, can be utilized in the field for a practical estimation of compaction resulting from the passage of a towed wheel.     

Highly emissive organic solids containing 2,5-diboryl-1,4-phenylene unit

We disclosed a series of pi-conjugated systems containing 2,5-bis(dimesitylboryl)-1,4-phenylene as the core unit and electron-donating amino groups at the terminal positions. The extension of the ppi-pi* conjugation in the diborylphenylene moiety along the short axis of the pi-conjugated framework as well as the incorporation of two bulky dimesitylboryl groups at the para-positions makes this moiety act as a unique bulky pi-electron-accepting unit. As a consequence, these systems behave like donor-acceptor-donor quadrupolar pi-electron systems and show a large solvatochromism in the fluorescence spectra. Moreover, these organoboron pi systems exhibit intense fluorescence even in the solid state with the quantum yields of 0.73-0.90.     

Chemical Modification and some Aligned Composites of Chitosan in a Filament State

The mono‐filaments (> 10 m in length) of chitosan and the blends of chitosan‐collagen, chitin‐collagen and chitin‐silk fibroin were wet‐spun. The mono‐filaments were chemically N‐modified with each of n‐fatty acid anhydrides, intra‐molecular carboxylic anhydrides, fragrant aldehydes and transition metal ions. The mono‐filament was aligned on a straight line with the mono‐filament of silk fibroin or poly(ethylene terephthalate) (PET), and a bundle of one to three mono‐filaments was coated with a medium of sericin (Se), chitosan or N‐acylchitosan to give rise to novel silk‐mimic filament composites. The filaments coated with a medium of sericin exhibited 26–27 denier for the titer, 2.46–3.36 gf · denier^?1 for the tenacity and 11.8–25.0% for the elongation. The apparent density (denier · μm^?1 in the filament diameter) of the filament composites was about 3–4 times higher than that of the mono‐filaments. Portion of fragrant aldehydes in Schiff's base was slowly hydrolyzed at room temperature by contacting with atmospheric moisture in the open air, and released from the fragrant filaments and composites. The filament composites coated with a chitosan medium were thrombogenic, and those coated with N‐acylchitosans were antithrombogenic.

An illustrated model for a silk‐mimic filament composite, N₀(N₂I‐FI).     

Heteroepitaxial growth of a zeolite film with a patterned surface-texture

We focus on the eteroepitaxial growth of trigonal chabazite with voids of three-dimensional intersection structures. The differences in the structures originate from the stacking sequences of the six-membered rings. Sodalite along 111 is constructed by an "abcabc" stacking sequence, while chabazite along [111] is constructed by "abab". Therefore, chabazite can grow heteroepitaxially on a sodalite substrate while keeping the relation of chabazite (111)//sodalite {111}. In this Communication, we report on the first success of the heteroepitaxial growth of a continuous zeolite (chabazite) film with a unique patterned surface-texture on a millimeter-sized sodalite single crystal. We have found that the unique texture of chabazite films is rationalized by the heteroepitaxial growth of chabazite on sodalite and the subsequent twin formation of chabazite.     

Experimental and theoretical studies of small-angle electron scattering by the water molecule

The total (elastic plus inelastic) intensities of 51 keV electrons scattered by water molecules have been measured over a range of 1 ≦ K = (4π/λ) sin(θ/2) ≦ 12 Å^?1. A computer program, ELIC, has been written for calculating the total intensities of electrons scattered by free molecules. The intensities can be calculated with self-consistent field and configuration interaction wavefunctions. The theoretical intensities based on a CI wavefunction are in good agreement with the observed intensities.     

Preparation of poly(arylenediphosphine)s by palladium‐catalyzed polycondensation: Formation of polymer transition‐metal complexes and catalytic reactions

The palladium‐catalyzed polycondensation of aryl diiodides with 1,3‐bis(phenylphosphino)propane afforded poly(arylenediphosphine)s in good yields. Treatment of the polyphosphine with elemental sulfur and hydrogen peroxide efficiently converted the polyphosphine into poly(arylenediphosphine sulfide) and poly(arylenediphosphine oxide), respectively. Treatment of the polyphosphines with Pd(II) and Pt(II) yielded corresponding polymer‐metal complexes with high metal contents. Application of the polymer‐Pd complexes in homogeneous and heterogeneous aryl alkynylation and carbonylation was examined. The polymer‐Pd complexes showed good catalytic activity similar to that of the corresponding low molecular weight Pd complex, and reuse of the polymer catalysts was easily achieved. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2637–2647, 2002