Monolithic DNApatite: An Elastic Apatite with Sub-Nanometer Scale Organo-Inorganic Structures.

Hydroxyapatite (HA) exhibits outstanding biocompatibility, bioactivity, osteoconductivity, and natural anti-inflammatory properties. Pure HA, ion-doped HA, and HA-polymer composites are investigated, but critical limitations such as brittleness remain; numerous efforts are being made to address them. Herein, the novel self-crystallization of a polymeric single-stranded deoxyribonucleic acid (ssDNA) without additional phosphate ions for synthesizing deoxyribonucleic apatite (DNApatite) is presented. The synthesized DNApatite, DNA1Ca2.2(PO4)1.3OH2.1, has a repetitive dual phase of inorganic HA crystals and amorphous organic ssDNA at the sub-nm scale, forming nanorods. Its mechanical properties, including toughness and elasticity, are significantly enhanced compared with those of HA nanorod, with a Young's modulus similar to that of natural bone.

Atomic-Level Observation of Potential-Dependent Variations at the Surface of an Oxide Catalyst during Oxygen Evolution Reaction.

Understanding the intricate details of the surface atomic structure and composition of catalysts during the oxygen evolution reaction (OER) is crucial for developing catalysts with high stability in water electrolyzers. While many notable studies highlight surface amorphization and reconstruction, systematic analytical tracing of the catalyst surface as a function of overpotential remains elusive. Heteroepitaxial (001) films of chemically stable and lattice-oxygen-inactive LaCoO3 are thus utilized as a model catalyst to demonstrate a series of atomic-resolution observations of the film surface at different anodic potentials. The first key finding is that atoms at the surface are fairly dynamic even at lower overpotentials. Angstrom-scale atomic displacements within the perovskite framework are identified below a certain potential level. Another noteworthy feature is that amorphization (or paracrystallization) with no long-range order is finally induced at higher overpotentials. In particular, surface analyses consistently support that the oxidation of lattice oxygen is coupled with amorphous phase formation at the high potentials. Theoretical calculations also reveal an upward shift of oxygen 2p states toward the Fermi level, indicating enhanced lattice oxygen activation when atom displacement occurs more extensively. This study emphasizes that the degradation behavior of OER catalysts can distinctively vary depending on the overpotential level.

Designing starch-based fenofibrate formulations using the melting method.

Fenofibrate (FNF) is used to treat hyperlipidemia. However, FNF is a poorly water-soluble drug, and the dosage of commercial products is relatively high at 160 mg in a Lipidil® tablet. Therefore, this study aimed to develop an FNF-solid dispersion (SD) that solubilizes and stabilizes FNF. The melting method that uses the low melting point of FNF was employed. The dissolution percentage of FNF in the optimal formulation (SD2) increased by 1.2-, 1.3-, and 1.3-fold at 5 min compared to that of Lipidil® and increased by 2.0-, 2.1-, and 2.0-fold compared to the pure FNF in pH 1.2 media, distilled water, and pH 6.8 buffer, which included 0.025 M sodium lauryl sulfate, respectively. The SD2 formulation showed a dissolution percentage of nearly 100 % in all dissolution media after 60 min. The physicochemical properties of the SD2 formulation exhibited slight changes in the melting point and crystallinity of FNF. Moreover, the stability of the SD2 formulation was maintained for six months. In particular, it was challenging to secure stability when starch#1500 was excluded from the SD2 formulation. In conclusion, the dissolution percentage of FNF in the SD2 formulation was improved owing to the weak binding force between FNF and the excipients, stability was secured, and favorable results are expected in future animal experiments.

Development of a tadalafil transdermal formulation and evaluation of its ability to in vitro transdermal permeate using Strat-M® membrane.

Tadalafil (TDF) has low water solubility, high intestinal permeability and belongs to the Biopharmaceutics Classification System (BCS) Class II. Due to high intestinal permeability, only oral administration (tablets) and oral thin film formulations have been developed. Therefore, it is necessary to develop various formulations, such as external formulations and transdermal absorption formulations requested by patients. The purpose of this study is to improve the solubility and skin permeability of TDF, and to develop a novel transdermal formulation with secured stability over time. The research strategy is to determine solvents that will improve TDF solubility and to screen substances that will enhance TDF permeability. Skin penetration tests were simulated by using a Strat-M® membrane in Franz diffusion cell systems. The optimal formulation (F1, consisting of TDF/HDTMA-Br at a ratio of 1:10 [weight/weight] in DPG) observed the highest permeability compared to all formulations in PBS (pH 7.4). Changes in thermal property of F1 formulation was observed and maintained its stability over 12 months including drug content (µg/mL), appearance, pH, and permeation (µg/cm2). In conclusion, DPG played a supported role in improving both TDF solubilization and permeability, whereas HDTMA-Br played a key role in enhancing permeability. It is thought that these results will be supplemented in the future to conduct research and experiments on humans.

Febuxostat solubilization and stabilization approach using solid dispersion method: Synergistic effect of dicalcium phosphate dehydrate and chitosan.

Drug solubilization studies are continuously being conducted. Febuxostat (FBX) has a low solubility in water. This study aims to develop a stable FBX-solid dispersion (SD) formulation using a solvent evaporation method. The solubilization strategy of FBX is to develope an optimal FBX-SD formulation by selecting a solubilizer and carrier through the screening method. The final selected solubilizer, macrogol 15 hydroxystearate and polyoxyl 15 hydroxystearate (Kolliphor® HS-15), is widely used in the pharmaceutical industry as a nonionic solubilizing and emulsifying agent and has low toxicity. Especially when commonly used in developing lipophilic drug formulations, it dissolves well in water and ethyl alcohol. The optimal composition ratio of the formulation (SD4) was FBX:HS-15®:granular dicalcium phosphate dehydrate (DCP-D): A synthetic magnesium aluminometasilicate (Neusilin®UFL2):chitosan = 1:3:3:1:1 (w/w) and showed 3.0-, 2.3-, and 1.1-fold higher dissolution (%) of FBX compared to that of the Feburic tab® in pH 1.2 media, distilled water (DW), and pH 6.8 buffer, respectively. Also, in vitro release and in vitro permeability in SD4 formulation showed higher than that of Feburic tab®. Based on its stability over 6 months, it was confirmed that chitosan acted as a stabilizer. Moreover, due to weak intermolecular interactions, FBX in the SD4 formulation was considered to exist in a mixed state of amorphous and crystalline FBX. In conclusion, the improved dissolution (%) and stability of FBX in SD4 formulation were secured through the synergistic effect of excipients.

Development and evaluation of febuxostat solid dispersion through screening method.

Febuxostat (Febux) is a BCS II drug and has a very low solubility. In order to overcome this shortcoming, the purpose of study is to increase the in vitro dissolution (%) and drug release (%) of Febux by using a screening method. The Febux-SD formulation was prepared by screening solubilizers, pH agents, and carriers using with a solvent evaporation method. The novel Febux SD formulation was successfully developed. The dissolution (%) of Febux of optimal formulation (SD3) was higher than that of Feburic® tab in pH 1.2, distilled water (DW), and pH 6.8 buffer by 6.3-, 2.6-, and 1.1-fold, respectively, at 60 min. The in vitro drug release (%) and permeability (µg/cm2) of SD3 formulation were improved compared to those of Feburic® tab in the pH shifting method and PBS (7.4), respectively. The SD3 formulation was well maintained the stability for 6 months, and that of physicochemical properties were altered. In conclusion, the Febux solubilization study with meglumine was first attempted and successfully performed. Through the improved dissolution (%) of Febux, high bioavailability of SD3 formulation is expected in animal and human studies.

Development and evaluation of niacinamide transdermal formulation by artificial membrane permeability.

Despite many efforts to improve the transdermal permeability of drugs, most of them are blocked by the skin barrier. Niacinamide (NAC) is a Biopharmaceutics Classification System class I drug with high aqueous solubility and intestinal permeability. Due to the high solubility and intestinal permeability of NAC, the development of new formulations is insufficient as transdermal, injection etc. Thus, this study aimed to develop the novel NAC formulation with improved skin permeability and secured stability. The NAC formulation approach is to first select a solvent that improves skin permeability, and then select a second penetration enhancer to determine the final formulation. All formulations were evaluated for skin permeability using an artificial membrane (Strat-M®). The optimal formulation (non-ionic formulations (NF1) consisted of NAC/Tween®80 = 1:1 wt ratio in dipropylene glycol [DPG]) showed the highest permeability in all formulations in PBS buffer (pH 7.4). The thermal properties of NF1 were altered. Moreover, NF1 maintained a stable drug content, appearance, and pH value for 12 months. In conclusion, DPG had an excellent effect in increasing the NAC permeation, and Tween®80 played a boosting role. Through this study, an innovative NAC formulation was developed, and good results are expected for human transdermal research.

Comparison of the Predictive Accuracy of Intraocular Lens Power Calculations after Phototherapeutic Keratectomy in Granular Corneal Dystrophy Type 2.

Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant disease affecting vision. Phototherapeutic keratectomy (PTK) is advantageous in removing vision-threatening corneal opacities and postponing keratoplasty; however, it potentially disturbs accurate intraocular lens (IOL) power calculation in cataract surgery. The myopic/hyperopic Haigis-L method with or without the central island has been reported; nevertheless, an optimal method has not yet been established. To compare the predictive accuracy of post-PTK IOL power calculations in GCD2, the retrospective data of 30 eyes from July 2017 to December 2020 were analyzed. All GCD2-affected eyes underwent post-PTK standard cataract surgery using the WaveLight EX500 platform (Alcon Laboratories, Inc., Fort Worth, TX, USA) under a single surgeon. The mean prediction error (MPE) and absolute error (MAE) with the myopic/hyperopic Haigis-L, Barrett Universal II, Barrett True-K, Haigis, and SRK/T by standard keratometry (K) and total keratometry (TK), where possible, were analyzed. Barrett Universal II and SRK/T showed significantly superior MPE, and MAE compared with the myopic/hyperopic Haigis-L method. TK was not significantly superior to K in the same formula. In conclusion, this study suggests that these biometries and formulas, especially Barrett Universal II and SRK/T, are potentially useful in IOL power calculation in GCD2 after PTK.

Viscosity-Controllable Graphene Oxide Colloids Using Electrophoretically Deposited Graphene Oxide Sheets.

Graphene oxide (GO) is one of the interesting ink materials owing to its fascinating properties, such as high dissolubility in water and high controllable electric properties. For versatile printing application, the viscosity of GO colloids should be controlled in order to meet the specific process requirements. Here, we report on the relatively rapid fabrication of viscosity-increased GO (VIGO) colloids mixed with electrophoretically deposited GO sheets (EPD-GO). As the GO colloid concentration, applied voltage, and deposition time increase, the viscosity of the GO colloids becomes high. The reason for the improved viscosity of GO colloids is because EPD-GO has parallel stacked GO sheets. The GO and VIGO colloids are compared and characterized using various chemical and structural analyzers. Consequently, our simple and fast method for the fabrication of GO colloids with enhanced viscosity can be used for producing inks for flexible and printed electronics.

Shear behavior of single cast-in anchor simulating characteristics of bridge bearing anchor.

A bridge bearing anchor transmits various loads of a superstructure to a substructure. Most anchors are generally designed without consideration of characteristics such as concrete pedestal, grout bedding, and anchor socket. This study investigated the shear behavior of anchors in accordance with the edge distance, embedment depth, compressive strength of concrete, and height of the concrete pedestal in order to simulate the practical characteristics of the bridge bearing anchors. The actual shear capacity of the anchor differs from the shear strengths calculated by the ACI 318 and EN 1992-4; especially, the importance of the embedment depth is underestimated in these codes. An increase in the height of the concrete pedestal has a negative effect on the shear capacity because of the stress concentration. The grout is fractured prior to the occurrence of local damages in concrete, resulting in a secondary moment. As a result, the effect of the level arm is observed. An equation, which can predict the relative cracking degree of concrete, is proposed by analyzing the displacement of grout and concrete. High strain occurs in the stirrups close to the anchor, and the behavior of the strain is more influenced by the embedment depth than the edge distance. The comparison of obtained and analytically evaluated failure loads by calculations according to EN 1992-4, Schmid model and Sharma model was conducted to consider the effect of supplementary reinforcement. Finally, the design equation of concrete breakout strength is modified to predict the more precise shear resistance of a bridge bearing anchor.

High Device Performances and Noise Characteristics of AlGaN/GaN HEMTs Using In Situ SiCN and SiN Cap Layer.

We fabricated and characterized AlGaN/GaN high-electron mobility transistors (HEMTs) with a nano-sized in situ cap layer (one is a silicon carbon nitride (SiCN) layer, and the other is a silicon nitride (SiN) layer) comparing to the conventional device without an in situ cap layer. The pulse characteristics and noise behaviors for two devices with in situ cap layers are much superior to those of the reference device without a cap layer, which means that the in situ cap layer effectively passivates the AlGaN surface. On the other hand, the device with an in situ SiCN cap layer showed the excellent device characteristics and noise performances compared to the other devices because of the reduced positive ionic charges and enhanced surface morphology caused by carbon (C) surfactant atoms during the growth of the SiCN cap layer. These results indicate that the AlGaN/GaN HEMT with the in situ SiCN cap layer is very promising for the next high-power device by replacing the conventional HEMT.

Interspersing CeOx Clusters to the Pt-TiO2 Interfaces for Catalytic Promotion of TiO2-Supported Pt Nanoparticles.

We propose an interface-engineered oxide-supported Pt nanoparticle-based catalyst with improved low-temperature activity toward CO oxidation. By wet-impregnating 1 wt % Ce on TiO2, we synthesized hybrid oxide support of CeOx-TiO2, in which dense CeOx clusters formed on the surface of TiO2. Then, the Pt/CeOx-TiO2 catalyst was synthesized by impregnating 2 wt % Pt on the CeOx-TiO2 supporting oxide. Pt-CeOx-TiO2 triphase interfaces were eventually formed upon impregnation of Pt on CeOx-TiO2. The Pt-CeOx-TiO2 interfaces open up the interface-mediated Mars-van Krevelen CO oxidation pathway, thus providing additional interfacial reaction sites for CO oxidation. Consequently, the specific reaction rate of Pt/CeOx-TiO2 for CO oxidation was increased by 3.2 times compared with that of Pt/TiO2 at 140 °C. Our results demonstrate a widely applicable and straightforward method of catalytic activation of the interfaces between metal nanoparticles and supporting oxides, which enabled fine-tuning of the catalytic performance of oxide-supported metal nanoparticle classes of heterogeneous catalysts.

Shielding Effectiveness and Impact Resistance of Concrete Walls Strengthened by High-Strength High-Ductility Concrete.

Following the fourth Industrial Revolution, electronic and data-based technology is becoming increasingly developed. However, current research on enhancing electromagnetic interference (EMI) shielding and the physical protection performance of structures incorporating these technologies is insufficient. Therefore, in this study aiming for the improvement of EMI shielding and structural performance of structures, twelve concrete walls were fabricated and tested to determine their shielding effectiveness and drop-weight impact resistance. Concrete walls strengthened by three thickness types of high-strength, high-ductility concrete (HSDC) have been considered. The test results showed that the shielding effectiveness with strengthening thickness increased by approximately 35.6-46.2%. Specimens strengthened by more than 40% and 10% of the strengthening area ratio of single- and double-layer, respectively, exhibited more than 20 dB of shielding effectiveness. Moreover, the relationship between the damaged area ratio and shielding effectiveness was evaluated by means of the drop-weight impact test. The structural performance and EMI shielding effectiveness improved as the HSDC thickness increased.

Mechanical and Electrical Characteristics of Lightweight Aggregate Concrete Reinforced with Steel Fibers.

There is increased interest in applying electromagnetic (EM) shielding to prevent EM interference, which destroys electronic circuits. The EM shielding's performance is closely related to the electrical conductivity and can be improved by incorporating conductive materials. The weight of a structure can be reduced by incorporating lightweight aggregates and replacing the steel rebars with CFRP rebars. In this study, the effects of lightweight coarse aggregate and CFRP rebars on the mechanical and electrical characteristics of concrete were investigated, considering the steel fibers' incorporation. The lightweight coarse aggregates decreased the density and strength of concrete and increased the electrical conductivity of the concrete, owing to its metallic contents. The steel fibers further increased the electrical conductivity of the lightweight aggregate concrete. These components improved the EM shielding performance, and the steel fibers showed the best performance by increasing shielding effectiveness by at least 23 dB. The CFRP rebars behaved similarly to steel rebars because of their carbon fiber content. When no steel fiber was mixed, the shielding effectiveness increased by approximately 2.8 times with reduced spacing of CFRP rebars. This study demonstrates that lightweight aggregate concrete reinforced with steel fibers exhibits superior mechanical and electrical characteristics for concrete and construction industries.

Building-Information-Modeling Based Approach to Simulate Strategic Location of Shelter in Place and Its Strengthening Method.

It is important to consider establishing a shelter in place (SIP) using existing facilities to prepare for unpredictable and no-notice disasters. In this study, we evaluate the building-information-modeling (BIM)-based approach to simulate the strategic location of SIP and its strengthening method. BIM software was used to model a light rail station and analyze the elements of the facility that can affect the evacuation time to reach the SIP. The purpose of this study was to understand the effects of structural standards on the design of SIPs using a direct simulation. The differences between domestic and overseas standards were analyzed. An analysis was carried out to evaluate whether national specifications are satisfactory. As the proposed evacuation method is based on a rational human behavior analysis through a direct simulation, it was going to be a safer and faster route of evacuation in the case of physical terror attack situations for existing infrastructure, Furthermore, the SIP design is considered where reinforcement of the SIP structure is necessary. Three types of reinforcing were considered. Here, the use of high-strength, high-ductility concrete proved to be an effective method to improve the impact resistance of reinforced concrete walls and recommended for strengthening reinforced concrete members.

Development and evaluation of pseudoephedrine hydrochloride abuse-deterrent formulations using thermal modified rice starch.

There is a continued global effort to prevent the spread of prescription drug abuse. In particular, chemical structure of pseudoephedrine hydrochloride (PSE), an over-the-counter medication, is very similar to that of methamphetamine (MET). The aim of this study was to develop abuse-deterrent formulations (ADF) of PSE by using thermal modified starch (TMR). PSE is a water-soluble drug, but it is intended to inhibit extraction from the extraction medium in excess tablets. Starch-based formulations were successfully developed using cross-linking agent and lipid. The extraction (%) of PSE from TMR7-L5 formulation (equivalent to 5 tablets) were 75.3% in DW, 2.7% in ethyl alcohol, and 63.0% in 40% ethyl alcohol (v/v) at 60 °C for 30 min. Moreover, TMR7-L5 formulation delayed drug release compared to the commercial product in in vitro release. In conclusion, the development of ADFs using a starch-based formulation shows novelty and has potential to prevent drug abuse.

Evaluation on the Microstructure and Durability of High-Strength Concrete Containing Electric Arc Furnace Oxidizing Slag.

The application of electric arc furnace oxidizing slag (EAS) in high strength concrete (HSC) as the cementitious material is investigated in this study. The microstructure and mechanical properties of HSC with four different replacement ratios of EAS were evaluated and HSC with two replacement ratios of ground granulated blast furnace slag (GBS) was used for performance comparison. The results show that the HSC with EAS replacement ratios smaller than 15% undergo similar hydration processes and result in a similar final product when compared with those of NC-NN. Increases in EAS replacement ratio cause a reduction in Ca(OH)2 content; this, in turn, leads to an increase in porosity and a reduction in compressive strength. In terms of shrinkage behavior under free conditions, mixtures with increasing replacement ratios of cementitious materials saw increasing shrinkage, with the HSC containing EAS being similar to the other specimens. The mixtures containing EAS saw a quite gradual decrease in their freezing and thawing resistance properties as the number of freeze-thaw cycles they underwent increased. However, the efficacy of HSC with less than 15% of EAS is similar to GBS; hence, EAS could replace cement in concrete for certain applications, which would lead to more environmental benefits.

Direct Growth of Highly Conductive Large-Area Stretchable Graphene.

The direct synthesis of inherently defect-free, large-area graphene on flexible substrates is a key technology for soft electronic devices. In the present work, in situ plasma-assisted thermal chemical vapor deposition is implemented in order to synthesize 4 in. diameter high-quality graphene directly on 10 nm thick Ti-buffered substrates at 100 °C. The in situ synthesized monolayer graphene displays outstanding stretching properties coupled with low sheet resistance. Further improved mechanical and electronic performances are achieved by the in situ multi-stacking of graphene. The four-layered graphene multi-stack is shown to display an ultralow resistance of ≈6 Ω sq-1, which is consistently maintained during the harsh repeat stretching tests and is assisted by self-p-doping under ambient conditions. Graphene-field effect transistors fabricated on polydimethylsiloxane substrates reveal an unprecedented hole mobility of ≈21 000 cm2 V-1 s-1 at a gate voltage of -4 V, irrespective of the channel length, which is consistently maintained during the repeat stretching test of 5000 cycles at 140% parallel strain.

Development of a naftopidil-chitosan-based fumaric acid solid dispersion to improve the dissolution rate and stability of naftopidil.

Naftopidil (NAF), an α1-adrenoceptor antagonist, is administered as a treatment for benign prostatic hyperplasia; however, according to the Biopharmaceutical Classification System (BCS IV), it is a poorly-soluble drug that exhibits poor permeability. We aimed to increase the dissolution (%) of NAF by adding chitosan to a polymer-free formulation. Compared to the formulation prepared using Flivas®, at 60 min, the solid dispersion (SD) formulation containing NAF, fumaric acid, chitosan, and US2® in a 1:1:2:1 weight ratio improved the dissolution (%) of NAF in distilled water, pH 1.2 media, pH 4.0 and pH 6.8 buffers by 27.2-, 1.2-, 1.1- and 6.5-fold, respectively. The physicochemical properties of the SD1 formulation were also found to be altered, including its thermal properties, crystal intensity, and chemical interaction. As a result, the hydrogen bonding that occurs between NAF and fumaric acid was identified as a major factor in the increase in NAF dissolution (%). Further, chitosan was observed to contribute to the stability of NAF and SD1, which was assessed over a 3-month period. To our knowledge, this is the first study to employ a polymer-free system to improve the solubilization of NAF.

Solubilization of tadalafil using a tartaric acid and chitosan-based multi-system.

Solubilization studies of tadalafil (TDF) have recently improved the dissolution (%) using weak acids and bases in our group. However, the weak acid formulations have a low dissolution (%) of TDF as limitation. Thus, the purpose of this study was to improve the dissolution (%) of TDF over 90% in distilled water (DW) by weak acid-chitosan based multi-system. The SD formulation (SD11: TDF, tartaric acid, chitosan, Aerosil®200, and PVP/VA S-630 in a 1:2:1:1:2 weight ratio) showed higher dissolution (%) of TDF by 5.0-, 6.0-, and 5.8-fold at 60 min than that of Cialis® in DW and pH 1.2 and pH 6.8 buffers, respectively. The physical properties of the SD11 formulation were changed. Moreover, the SD11 formulation maintained stability for 3 months. In conclusion, the solubilization of TDF using chitosan was successfully performed for the first time.