Phenylboronic acid-diol crosslinked 6-<i>O</i>-vinylazeloyl-d-galactose nanocarriers for insulin delivery

A new block polymer named poly 3-acrylamidophenylboronic acid-b-6-O–vinylazeloyl-d-galactose (p(AAPBA-b-OVZG)) was prepared using 3-acrylamidophenylboronic acid (AAPBA) and 6-O-vinylazeloyl-D-galactose (OVZG) via a two-step procedure involving S-1-dodecyl-S-(α', α'-dimethyl-α″-acetic acid) trithiocarbonate (DDATC) as chain transfer agent, 2,2-azobisisobutyronitrile (AIBN) as initiator and dimethyl formamide (DMF) as solvent. The structures of the polymer were examined by Fourier transform infrared spectroscopy (FT-IR) and 1H NMR and the thermal stability was determined by thermal gravimetric analysis (TG/DTG). Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were utilized to evaluate the morphology and properties of the p(AAPBA-b-OVZG) nanoparticles. The cell toxicity, animal toxicity and therapeutic efficacy were also investigated. The results indicate the p(AAPBA-b-OVZG) was successfully synthesized and had excellent thermal stability. Moreover, the p(AAPBA-b-OVZG) nanoparticles were submicron in size and glucose-sensitive in phosphate-buffered saline (PBS). In addition, insulin as a model drug had a high encapsulation efficiency and loading capacity and the release of insulin was increased at higher glucose levels. Furthermore, the nanoparticles showed a low-toxicity in cell and animal studies and they were effective at decreasing blood glucose levels of mice over 96 h. These p(AAPBA-b-OVZG) nanoparticles show promise for applications in diabetes treatment using insulin or other hypoglycemic proteins

Coherent versus Incoherent Light Scattering from a Quantum Dot

We analyze the light scattered by a single InAs quantum dot interacting with a resonant continuous-wave laser. High resolution spectra reveal clear distinctions between coherent and incoherent scattering, with the laser intensity spanning over four orders of magnitude. We find that the fraction of coherently scattered photons can approach unity under sufficiently weak or detuned excitation, ruling out pure dephasing as a relevant decoherence mechanism. We show how spectral diffusion shapes spectra, correlation functions, and phase-coherence, concealing the ideal radiatively-broadened two-level system described by Mollow.Comment: to appear in PRB 85, 23531

Fabrication and investigation of a biocompatible microfilament with high mechanical performance based on regenerated bacterial cellulose and bacterial cellulose

A high-strength regenerated bacterial cellulose (RBC)/bacterial cellulose (BC) microfilament of potential use as a biomaterial was successfully prepared via a wet spinning process. The BC not only consists of a 3-D network composed of nanofibers with a diameter of several hundred nanometers but also has a secondary structure consisting of highly oriented nanofibrils with a diameter ranging from a few nanometers to tens of nanometers which explains the reason for the high mechanical strength of BC. Furthermore, a strategy of partially dissolving BC was used and this greatly enhanced the mechanical performance of spun filament and a method called post-treatment was utilized to remove residual solvents from the RBC/BC filaments. A comparison of structure, properties, as well as cytocompatibility between BC nanofibers and RBC/BC microfilaments was achieved using morphology, mechanical properties, X-ray Diffraction (XRD) and an enzymatic hydrolysis assay. The RBC/BC microfilament has a uniform groove structure with a diameter of 50–60 μm and XRD indicated that the crystal form was transformed from cellulose Iα to cellulose IIII and the degree of crystallinity of RBC/BC (33.22%) was much lower than the original BC (60.29%). The enzymatic hydrolysis assay proved that the RBC/BC material was more easily degraded than BC. ICP detection indicated that the residual amount of lithium was 0.07 mg/g (w/w) and GC–MS analysis showed the residual amount of DMAc to be 8.51 μg/g (w/w) demonstrating that the post-treatment process is necessary and effective for removal of residual materials from the RBC/BC microfilaments. Also, a cell viability assay demonstrated that after post-treatment the RBC/BC filaments had good cytocompatibility

A Nacre-Like Carbon Nanotube Sheet for High Performance Li-Polysulfide Batteries with High Sulfur Loading

© 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Lithium-sulfur (Li-S) batteries are considered as one of the most promising energy storage systems for next-generation electric vehicles because of their high-energy density. However, the poor cyclic stability, especially at a high sulfur loading, is the major obstacles retarding their practical use. Inspired by the nacre structure of an abalone, a similar configuration consisting of layered carbon nanotube (CNT) matrix and compactly embedded sulfur is designed as the cathode for Li-S batteries, which are realized by a well-designed unidirectional freeze-drying approach. The compact and lamellar configuration with closely contacted neighboring CNT layers and the strong interaction between the highly conductive network and polysulfides have realized a high sulfur loading with significantly restrained polysulfide shuttling, resulting in a superior cyclic stability and an excellent rate performance for the produced Li-S batteries. Typically, with a sulfur loading of 5 mg cm−2, the assembled batteries demonstrate discharge capacities of 1236 mAh g−1 at 0.1 C, 498 mAh g−1 at 2 C and moreover, when the sulfur loading is further increased to 10 mg cm−2 coupling with a carbon-coated separator, a superhigh areal capacity of 11.0 mAh cm−2 is achieved

The impact of point mutations in the human androgen receptor : classification of mutations on the basis of transcriptional activity

Peer reviewedPublisher PD

Thermodynamic Simulation of the RDX-Aluminum Interface Using ReaxFF Molecular Dynamics

We use reactive molecular dynamics (RMD) simulations to study the interface between cyclotrimethylene trinitramine (RDX) and aluminum (Al) with different oxide layers to elucidate the effect of nanosized Al on thermal decomposition of RDX. A published ReaxFF force field for C/H/N/O elements was retrained to incorporate Al interactions and then used in RMD simulations to characterize compound energetic materials. We find that the predicted adsorption energies for RDX on the Al(111) surface and the apparent activation energies of RDX and RDX/Al are in agreement with ab initio calculations. The Al(111) surface-assisted decomposition of RDX occurs spontaneously without potential barriers, but the decomposition rate becomes slow when compared with that for RDX powder. We also find that the Al(111) surface with an oxide layer (Al oxide) slightly increases the potential barriers for decomposition of RDX molecules, while α-Al_2O_3(0001) retards thermal decomposition of RDX, due to the changes in thermal decomposition kinetics. The most likely mechanism for the thermal decomposition of RDX powder is described by the Avrami–Erofeev equation, with n = 3/4, as random nucleation and subsequent growth model. Although the decomposition mechanism of RDX molecules in the RDX/Al matrix complies with three-dimensional diffusion, Jander’s equation for RDX(210)/Al oxide and the Zhuralev–Lesokin–Tempelman (Z-L-T) equation for RDX(210)/Al_2O_3(0001) provide a more accurate description. We conclude that the origin of these differences in dynamic behavior is due to the variations in the oxide layer morphologies

Effects of Molecular Structure and Packing Order on the Stretchability of Semicrystalline Conjugated Poly(Tetrathienoacene-diketopyrrolopyrrole) Polymers

The design of polymer semiconductors possessing high charge transport performance, coupled with good ductility, remains a challenge. Understanding the distribution and behavior of both crystalline domains and amorphous regions in conjugated polymer films, upon an applied stress, shall provide general guiding principles to design stretchable organic semiconductors. Structure–property relationships (especially in both side chain and backbone engineering) are investigated for a series of poly(tetrathienoacene-diketopyrrolopyrrole) polymers. It is observed that the fused thiophene diketopyrrolopyrrole-based polymer, when incorporated with branched side chains and an additional thiophene spacer in the backbone, exhibits improved mechanical endurance and, in addition, does not show crack propagation until 40% strain. Furthermore, this polymer exhibits a hole mobility of 0.1 cm2 V−1 s−1 even at 100% strain or after recovered from strain, which reveals prominent continuity and viscoelasticity of the polymer thin film. It is also observed that the molecular packing orientations (either edge-on or face-on) significantly affect the mechanical compliance of the polymer films. The improved stretchability of the polymers is attributed to both the presence of soft amorphous regions and the intrinsic packing arrangement of its crystalline domains

Measurement of azimuthal asymmetries in inclusive charged dipion production in e+e−e^+e^- annihilations at s\sqrt{s} = 3.65 GeV

We present a measurement of the azimuthal asymmetries of two charged pions in the inclusive process $e^+e^-\rightarrow \pi\pi X$ based on a data set of 62 $\rm{pb}^{-1}$ at the center-of-mass energy $\sqrt{s}=3.65$ GeV collected with the BESIII detector. These asymmetries can be attributed to the Collins fragmentation function. We observe a nonzero asymmetry, which increases with increasing pion momentum. As our energy scale is close to that of the existing semi-inclusive deep inelastic scattering experimental data, the measured asymmetries are important inputs for the global analysis of extracting the quark transversity distribution inside the nucleon and are valuable to explore the energy evolution of the spin-dependent fragmentation function.Comment: 7 pages, 5 figure