Side chain dynamics in semiconducting polymer MEH-PPV

The characteristic nanoscale dynamics of the alkyl side groups in the light-emitting polymer poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] have been investigated using quasi-elastic neutron scattering (QENS). The measurements were taken below the polymer's glass transition (T ≤ T_g ≃ 353 K), where the main backbone is in a rigid state and does not contribute to the broadening of the QENS signal. An analytical diffusion model consisting of a static term and two dynamical components, characterizing the flexible side groups, provide an excellent fit to the experimental data. The two observed dynamical processes are all localized in character, with no meaningful dependence on temperature. The faster process, with characteristic timescale of ∼18 ps at room temperature (RT), can be linked to the average mobility of the terminal protons of the alkyl chain, while the slower process, with characteristic timescale of ∼170 ps at RT, to those protons at the other end of the alkyl chain, closest to the backbone. While the fraction of mobile protons contributing to the QENS signal increases with increasing temperature, the characteristic timescale and confining volume within which the protons are able to move locally depend chiefly on the polymer conformational state. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47394.     

Effects of black raspberry extract on gut microbiota,microbial metabolites,and expressions of the genes involved in cholesterol and bile acid metabolisms in rats fed excessive choline with a high-fat diet

Food Science and Biotechnology - In our previous study, black raspberry (BR) reduced the serum levels of trimethylamine-N-oxide and cholesterol in rats fed excessive choline with a...     

Multiwalled carbon nanotubes and nanofibers grafted with polyetherketones in mild and viscous polymeric acid

Direct covalent attachment of amorphous and semicrystalline polyetherketones onto the surface of either an as-received multi-walled carbon nanotube (MWNT) or a vapor-grown carbon nanofiber (VGCNF) in polyphosphoric acid (PPA) with optimized P₂O₅ content resulted in uniform grafting of polyetherketones to these carbon nanoscale materials. Soxhlet extraction experiment, the spectra from FT-IR spectroscopy and the clear images from high-resolution transmission electron microscopy showed that the covalent attachment is effective in uniformly coating the PEK grafts on the surfaces of both MWNT and VGCNF. Additionally, a drastic increase in solution viscosity due to the formation of giant molecules was monitored during polymerization. As such, the resulting nanocomposites were easily fabricated via a simple compression molding technique. The alignment possibility of MWNT and VGCNF grafted with semicrystalline PEK in these thermoplastic nanocomposites via solution fiber spinning was also demonstrated.     

Ferroelectricity and Antiferroelectricity of Doped Thin HfO2‐Based Films

The recent progress in ferroelectricity and antiferroelectricity in HfO₂‐based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O₃, BaTiO₃, and SrBi₂Ta₂O₉, which are considered to be feasible candidate materials for non‐volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si‐compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si‐doped HfO₂ thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro­electricity or antiferroelectricity in thin HfO₂ films. They have large remanent polarization of up to 45 μC cm^?2, and their coercive field (≈1–2 MV cm^?1) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (<10 nm) and have a large bandgap (>5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field‐effect‐transistors and three‐dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid‐state‐cooling, and infrared sensors.     

A bench-scale aeration study using batch reactors on swine manure stabilization to control odour in post treatment storage

A bench-scale study on swine manure stabilization for odour control was conducted using batch aeration reactors. In trial 1, two aeration lengths, i.e., 0.5 and 4.0 day, were used under uncontrolled ambient temperature that increased gradually over the experimental period. While in trial 2, a 16.0-day aeration scheme was employed under constant 17 degrees C. An airflow rate of 1.2L/s/m(3) was used for both trials to aerate batch reactors containing finishing pig manure with initial total solids (TS) levels ranging from 0.5 to 4.0%. Manure stabilization during the 90-day post-treatment storage was evaluated by the changes in organic materials, nitrogen and volatile fatty acids (VFA). The odour generation potential in the treated manure was determined by the changes in VFA. Up to 827 mL of liquid was lost due to aeration related foaming. The reductions in total volatile solids (TVS), 5-day biochemical oxygen demand (BOD(5)), total Kjeldahl nitrogen (TKN) and VFA during storage were improved when aeration length increased. Low solids levels offered a more advantageous circumstance for manure stabilization and odour control. Biodegradation of organic matter, removal of nitrogen, and breakdown of VFA would increase with increasing ambient temperature. VFA removals in manure under 16.0-day aeration were higher than those under 0.5- and 4.0-day aeration; however, VFA regeneration started to exceed its consumption on day 20 (4 days after the aeration treatment). BOD(5) was the best estimate of VFA concentration in the aerated manure during storage. The 4.0-day aeration scheme was sufficient to stabilize manure to effectively assuage odour generation potential during the 90-day storage under increasing ambient temperature conditions.     

Deuterated dicondensed indolinobenzospiropyran formed from the reaction of Fischer base-d2 and salicylaldehyde: Mechanism involving a carbinol intermediate

From the deuterium content (x-value) of deuterated molecules obtained from the reaction of an excess of Fischer base-d₂ with salicylaldehydes, it is found that the formation of the dicondensed indolinobenzospiropyrans occurred via a carbinol intermediate, rather than an open merocyanine form of spiropyran. ¹H NMR behavior supported this proposed mechanism, indicating that a carbinol intermediate was simultaneously, and not consecutively, formed prior to the transformation to both spiropyrans and dicondensed indolinobenzospiropyran.     

Efficient Puncturing Method for Rate-Compatible Low-Density Parity-Check Codes

In this paper, we propose an efficient puncturing method for LDPC codes. The proposed algorithm provides the order of variable nodes for puncturing based on the proposed cost function. The proposed cost function tries to maximize the minimum reliability among those provided from all check nodes. Also, it tries to allocate survived check nodes evenly to all punctured variable nodes. Furthermore, the proposed algorithm prevents the formation of a stopping set from the punctured variable nodes even when the amount of puncturing is quite large. Simulation results show that the proposed punctured LDPC codes perform better than existing punctured LDPC codes.     

Design, assembly, and activity of antisense DNA nanostructures

Discrete DNA nanostructures allow simultaneous features not possible with traditional DNA forms: encapsulation of cargo, display of multiple ligands, and resistance to enzymatic digestion. These properties suggested using DNA nanostructures as a delivery platform. Here, DNA pyramids displaying antisense motifs are shown to be able to specifically degrade mRNA and inhibit protein expression in vitro, and they show improved cell uptake and gene silencing when compared to linear DNA. Furthermore, the activity of these pyramids can be regulated by the introduction of an appropriate complementary strand. These results highlight the versatility of DNA nanostructures as functional devices.