Genetic Control of Aerogel and Nanofoam Properties,Applied to Ni–MnOx Cathode Design

Aerogels are ultralight porous materials whose matrix structure can be formed by interlinking 880 nm long M13 phage particles. In theory, changing the phage properties would alter the aerogel matrix, but attempting this using the current production system leads to heterogeneous lengths. A phagemid system that yields a narrow length distribution that can be tuned in 0.3 nm increments from 50 to 2500 nm is designed and, independently, the persistence length varies from 14 to 68 nm by mutating the coat protein. A robotic workflow that automates each step from DNA construction to aerogel synthesis is used to build 1200 aerogels. This is applied to compare Ni–MnO_x cathodes built using different matrixes, revealing a pareto-optimal relationship between performance metrics. This work demonstrates the application of genetic engineering to create “tuning knobs” to sweep through material parameter space; in this case, toward creating a physically strong and high-capacity battery.     

Physicochemical Properties in 3D Hydrogel Modulate Cellular Reprogramming into Induced Pluripotent Stem Cells

Understanding the biophysical relationships between stem cells and applied biomaterials can facilitate the ability to control the functions and behaviors of stem cells. However, the role of 3D microenvironment in stem cell biology remains largely unexplored, compared with that of 2D cell-culture environment. Here, a new strategy that improves the efficacy of Yamanaka's four-factor-induced cellular reprogramming into induced pluripotent stem cells (iPSCs) by incorporating cues derived from the 3D microenvironment and biophysical ligands is reported. Among the various 3D hydrogel systems tested, methacrylated hyaluronic acid (HA) hydrogel significantly improves cellular reprogramming into iPSCs. Additionally, the initial upregulation of CD44 in encapsulated cells in low-level methacrylated soft HA hydrogel accelerates the reprogramming. In conclusion, the reported HA hydrogel with low modulus accelerates reprogramming into iPSCs and thus offers potential advantages for translational applications.     

Natural Radioactivity in Polish Coal Mines: An Attempt to Assess the Trend of Radium Release into the Environment

The highly mineralised formation waters in the coal mines of Poland’s Upper Silesian Coal Basin contain natural radioactive nuclides, mostly radium. The ²²⁶Ra concentration in the groundwater that flows into the underground mine workings reaches 390 Bq/L, and is sometimes exceeded by the ²²⁸Ra concentration. The radium-bearing water sometimes also contain barium ions, which enables coprecipitation of barium-radium sulphate. Another type of radium-bearing water contains sulphate ions instead of barium; in this case, radium is transported to settling ponds and downstream. We have assessed the daily activity of radium in waters flowing into the underground mines and being discharged to the environment. Based on 1995 data, we estimate that the total activity of radium isotopes flowing into the mines was about 1300 MBq/day, while the radium activity in the discharge waters was about 700 MBq/day. A similar assessment performed with 2016 data indicated that the total activity in inflows was roughly 1150 MBq/day, while that discharged to surface waters was about 450 MBq/day.

     

Effect of Minor Alloying Elements on the Oxidation Behavior of Ni-Base Alloys in a High-Temperature Steam Environment

Oxidation of Metals - Model alloys based on Alloy 617 were fabricated with modified minor alloying elements for improvement in oxidation resistance in high-temperature steam environments. Model...     

Effect of hydrocolloids on functionality of Protaetia brevitarsis proteins

Food Science and Biotechnology - In this study, the effects of various hydrocolloids on the functionality of extracted proteins from Protaetia brevitarsis were investigated. Gel solubility,...     

Flame characteristics in H2/CO synthetic gas diffusion flames diluted with CO2: Effects of radiative heat loss and mixture composition

Numerical study is conducted to understand the impact of fuel composition and flame radiation in flame structure and their oxidation process in H₂/CO synthetic gas diffusion flame with and without CO₂ dilution. The models of Sun et al. and David et al., which have been well known to be best-fitted for H₂/CO synthetic mixture flames, are evaluated for H₂/CO synthetic mixture flames diluted with CO₂. Effects of radiative heat loss to flame characteristics are also examined in terms of syngas mixture composition. Importantly contributing reaction steps to heat release rate are compared for the synthetic gas mixture flames of high contents of H₂ and CO, individually, with and without CO₂ dilution. The modification of the oxidation pathways is also addressed.     

Biodegradable Polymer Crosslinker: Independent Control of Stiffness,Toughness, and Hydrogel Degradation Rate

Hydrogels are being increasingly studied for use in various biomedical applications including drug delivery and tissue engineering. The successful use of a hydrogel in these applications greatly relies on a refined control of the mechanical properties including stiffness, toughness, and the degradation rate. However, it is still challenging to control the hydrogel properties in an independent manner due to the interdependency between hydrogel properties. Here it is hypothesized that a biodegradable polymeric crosslinker would allow for decoupling of the dependency between the properties of various hydrogel materials. This hypothesis is examined using oxidized methacrylic alginate (OMA). The OMA is synthesized by partially oxidizing alginate to generate hydrolytically labile units and conjugating methacrylic groups. It is used to crosslink poly(ethylene glycol) methacrylate and poly(N‐hydroxymethyl acrylamide) to form three‐dimensional hydrogel systems. OMA significantly improves rigidity and toughness of both hydrogels as compared with a small molecule crosslinker, and also controls the degradation rate of hydrogels depending on the oxidation degree, without altering their initial mechanical properties. The protein‐release rate from a hydrogel and subsequent angiogenesis in vivo are thus regulated with the chemical structure of OMA. Overall, the results of this study suggests that the use of OMA as a crosslinker will allow the implantation of a hydrogel in tissue subject to an external mechanical loading with a desired protein‐release profile. The OMA synthesized in this study will be, therefore, highly useful to independently control the mechanical properties and degradation rate of a wide array of hydrogels.     

Fabrication and Reliability of Rigid-Flexible Optical Electrical Printed Circuit Board for Mobile Devices

A rigid-flexible optical and electrical printed circuit board (RFOE-PCB) was fabricated using a conventional PCB manufacturing process for mobile devices. The RFOE-PCB was designed to be embedded with a flexible 45-ended optical waveguide. In order to apply it to mobile devices, a repeating folding test and an environment test were carried out for physical and optical reliability. The RFOE-PCB successfully passed the reliability tests.