Hierarchical Organization of Structurally Colored Cholesteric Phases of Cellulose via 3D Printing

Structural color—a widespread phenomenon observed throughout nature is caused by light interference from ordered phases of matter. While state-of-the-art nanofabrication techniques can produce structural organization in small areas, cost-effective and scalable techniques are still lacking to generate tunable color at sub-micron length scales. In this work, structurally colored hydroxypropyl cellulose filaments are produced with a suppressed angular color response by 3D printing. The systematic study of the morphology of the filaments reveals the key stages in the induction of a two-degree hierarchical order through 3D printing. The first degree of order originated from the changing of the cholesteric pitch at a few hundred nm scale via chemical modification and tuning of the solid content of the lyotropic phase. Upon 3D printing, the secondary hierarchical order of periodic wrinkling is introduced through the Helfrich–Hurault deformation of the shear-aligned cholesteric phases. In single-layered filaments, four morphological zones with varying orders of wrinkles are identified. Detailed morphological characterization is carried out using SEM to shed light on the mechanism of the wrinkling behavior. Through this work, the possibility of modifying the wrinkling behavior is demonstrated and thus the angle dependence of the color response by changing the printing conditions.     

Mixed levels of coarse-graining of large proteins using elastic network model succeeds in extracting the slowest motions

We perform a mixed coarse-graining approach in a normal mode analysis of protein motions, which enables the modeling of a protein's native conformation with different regions having low and high resolution. As a result, the dynamics of the interesting functional parts within a supramolecular assemblage can be analyzed at high resolution, while the remainder of the structure is represented at poorer resolution, thus keeping the total number of nodes in the system sufficiently low for computational tractability. Our results indicate that the vibrational dynamics of specific components in a large multi-subunit protein are best described by retaining all the components of the structure, whether at higher or lower resolution. It is also shown that similar frequency distributions are obtained for different proteins and at different levels of coarse-graining, at the lower end of the spectrum, where the most significant slowest motions occur.     

Conductivity hysteresis in polymer electrolytes incorporating poly(tetrahydrofuran)

Conductivity hysteresis and room temperature ionic conductivities >10⁻³ S/cm were recently reported for electrolytes prepared from blends of an amphiphilic comb copolymer, poly[2,5,8,11,14-pentaoxapentadecamethylene (5-hexadecyloxy-1,3-phenylene)] (polymer I), and a linear multiblock copolymer, poly(oligotetrahydrofuran-co-dodecamethylene) (polymer II), following thermal treatment [F. Chia, Y. Zheng, J. Liu, N. Reeves, G. Ungar, P.V. Wright, Electrochim. Acta 43 (2003) 1939]. To investigate the origin of these effects, polymers I and II were synthesized in this work, and the conductivity and thermal properties of the individual polymers were investigated. AC impedance measurements were conducted on I and II doped with LiBF₄ or LiClO₄ during gradual heating to 110 °C and slow cooling to room temperature. Significant conductivity hysteresis was seen for polymer II, and was similarly observed for poly(tetrahydrofuran) (PTHF) homopolymer at equivalent doping levels. From thermogravimetic analysis (TGA), gel permeation chromatography (GPC) and ¹H NMR spectroscopy, both polymer II and PTHF were found to partially decompose to THF during heat treatment, resulting in a self-plasticizing effect on conductivity.     

Effects of infill walls on base responses and roof drift of reinforced concrete buildings under time‐history loading

In this study, the effects of infill walls on base reaction and roof drift of reinforced concrete frames were investigated. These effects were studied using 3D finite element method on 216 building models. Number of floors, number of bays, ratio of shear walls and ratio of infilled bays were selected as parameters. Sensitivity analysis was performed to determine the effect of each parameter on base shear, normal base reaction and roof drift. Based on the sensitivity analysis, the percentage of shear walls was the most important parameter affecting base shear, normal base reaction and roof drift. The effect of infill walls on base shear, normal base reaction and roof drift decreased when the percentage of the shear walls increased. The models without any infill walls had minimal normal base reaction under time‐history loading. However, an increase in the percentage of infill walls led to an increase in normal base reaction. The roof drift of the models was not critical. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of laser etching on the fracture strength of the monolithic zirconia and fiber-reinforced composite inlay-retained fixed partial dentures

Aim: The aim of this study was to evaluate the fracture strength of monolithic zirconia and fiber-reinforced composite (FRC) inlay-retained FPDs, both of which are cemented to the laser-etched cavity surfaces.

Materials and Methods: Eighty freshly extracted sound human teeth were used. A premolar and a molar tooth were embedded in an autopolymerizing acrylic resin. Forty acrylic resin models were randomly divided into two groups including monolithic zirconia and FRC inlay-retained FPDs (n = 20). Then, these groups were divided into two subgroups according to conditioning of the cavity surfaces with or without Er:YAG laser etching. Monolithic zirconia inlay-retained FPDs were produced by an inLab MC XL milling device using monolithic zirconia blocks. Tescera? Fiber Reinforcement Materials were used for the FRC inlay-retained FPDs. After 10.000 thermal cycles, fracture strength test was applied to the specimens.

Results: The monolithic zirconia inlay-retained FPDs exhibited the highest fracture strength than the FRC inlay-retained FPDs. Fracture strength was increased with laser etching for both restorative materials (p < 0.05).

Conclusion: Laser etching had positively effect on the fracture strength of the inlay-retained FDPs.     

A Study on Degree of Starch Gelatinization in Cakes Baked in Three Different Ovens

The main objective of the study was to determine the effects of different baking ovens and different cake formulations on the degree of starch gelatinization during cake baking. Baking was performed in microwave, infrared–microwave combination, and conventional ovens. Starch gelatinization levels of fat free, 25% fat, and 25% Simplesse™-containing cake samples were examined using differential scanning calorimeter (DSC) and rapid visco analyzer (RVA). Both DSC and RVA results showed that increasing baking time increased gelatinization level for all baking types significantly. It was also found that the effect of fat content on starch gelatinization was different depending on the type of baking. Addition of fat reduced the degree of starch gelatinization in conventional baking. However, fat enhanced the gelatinization in microwave and infrared–microwave combination ovens. Usage of Simplesse™ as a fat replacer decreased the starch gelatinization in all types of baking significantly. There was insufficient starch gelatinization in microwave-baked cakes in which the degree of gelatinization ranged from 55% to 78% depending on formulation. On the other hand, it ranged from 85% to 93% in conventionally baked cakes. Combining infrared with microwaves increased degree of starch gelatinization (70–90%).     

Separation of Nanoparticles in Aqueous Multiphase Systems through Centrifugation

This paper demonstrates the use of aqueous multiphase systems (MuPSs) as media for rate-zonal centrifugation to separate nanoparticles of different shapes and sizes. The properties of MuPSs do not change with time or during centrifugation; this stability facilitates sample collection after separation. A three-phase system demonstrates the separation of the reaction products (nanorods, nanospheres, and large particles) of a synthesis of gold nanorods, and enriches the nanorods from 48 to 99% in less than ten minutes using a benchtop centrifuge.     

A multiscale investigation on controlling bovine serum albumin adsorption onto polyurethane films

Our previous study on castor oil (CO) and poly(ethylene glycol) (PEG)‐based shape memory polyurethane (PU) films indicated that cell spreading on the polymer surface, cell morphology, and adhesion of fibroblast are closely related to the composition of the polymer that influences surface properties. This integrated experimental and computational study is designed to investigate the effect of important parameters such as surface roughness, crystallinity, hydrophilicity, distribution of hard/soft segments, and topology of the surface on protein adsorption for CO‐ and PEG‐based PUs. Analyses indicate that the crystallinity percentage highly promotes bovine serum albumin (BSA) adsorption. Roughness together with topological features determines BSA adsorption rate and concentration. Hydrophilicity and hard segment content seem to have less critical effect on adsorption. Distribution of hard segments into the soft segments emerges as another important factor for protein adsorption. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45669.     

Single Multiplicative Neuron Model Artificial Neural Network with Autoregressive Coefficient for Time Series Modelling

Neural Processing Letters - Single multiplicative neuron model and multilayer perceptron have been commonly used for time series prediction problem. Having a simple structure and features of easily...     

A computational and experimental approach to develop minocycline-imprinted hydrogels and determination of their drug delivery performances

In this study, minocycline-imprinted hydrogels are developed for controlled drug delivery in ocular disease treatments. An integrated computational and experimental study are conducted for investigating the relationship between design parameters and the drug loading/release performance of hydrogels. First, suitable functional monomers are determined for successful drug-imprinting by studying pre-polymerization conditions with full-atom molecular dynamics (MD) simulations. MD simulations suggest that acrylic acid and itaconic acid are suitable monomers for imprinting minocycline. Then, minocycline-imprinted hydrogels are synthesized with acrylic acid, commonly used in hydrogels, and three different amounts of cross-linker ethylene glycol dimethacrylate, 1, 2 and 3 mol%. All hydrogels are characterized and their drug loading and release performances are determined. Our computational and experimental calculations indicate an optimum cross-linker amount of 2 mol% for controlled minocycline release from imprinted hydrogels with an imprinting factor of almost 3. Finally, the drug release kinetics are determined by Korsmeyer-Peppas model.