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It is of great significance to efficiently prepare core-shell nanoparticles. In this study, we directly and efficiently prepared core-shell structured PCL/PEG nanoparticles based on shell insertion strategy by using coaxial electrospray. The key points to ensure the success of this new strategy include: the preparation of PCL particles with size less than 100 nm which worked as core structure; the insertion of PEG into PCL surface which worked as shell structure. We directly fabricated PCL particles with size less than 100 nm by using shell evaporation coaxial electrospray method. It means that PCL nanoparticles could be prepared and used as core structure through coaxial electrospray method. PEG solution worked as shell layer, PCL solution worked as core layer, PCL/PEG core shell structured microparticles were obtained through coaxial electrospray technique. Because of the solvent diffusion during the coaxial electrospray process, PEG could insert into PCL when TFE was used as the solvent of both core and shell layer. Then, after removing uninserted PEG, PCL/PEG nanoparticles with core-shell structure were fabricated successfully. The core-shell structured nanoparticles were stored at 4 °C and were stable without changing size for at least 7 days. This method can easily prepare core-shell structured nanoparticle with different size by changing the injection speed of PCL solution.

Granulocyte colony-stimulating factor (G-CSF) has been shown to reduce lesion volume and improve functional outcome in experimental stroke models. However, whether G-CSF plays a role currently in patients with stroke remains uncertain. Our study aimed at examining the efficacy and safety of G-CSF in patients with acute ischemic stroke.A comprehensive search was conducted in 5 online databases up to April 2014, and 10 studies with 711 patients met the criteria.The results showed that G-CSF was beneficial in improving the National Institutes of Health Stroke Scale (standardized mean difference [SMD], .43; 95% confidence interval [CI], .03-.82; P = .04) and modified Rankin Scale (mRS) scores (SMD, .72; 95% CI, .51-.93; P = .01), and elevating CD34(+) count (P.001). No treatment effects were found in Barthel Index scores (SMD, -.13; 95% CI, -.61 to .35; P = .59), serious adverse events (relative ratio [RR], 1.12; 95% CI, .91-1.38; P = .28), or the death of serious adverse events (RR, 1.25; 95% CI, .82-1.91; P = .30) between groups at day 90. Adverse effect on vascular complications was not detected to be increased although G-CSF produced a marked elevation in the total leukocyte count (SMD, 3.52; 95% CI, 2.54-4.49; P.001).In conclusion, G-CSF is effective at mobilizing bone marrow-derived CD34(+) stem cells to the peripheral blood. It also seems to improve the National Institutes of Health Stroke Scale and mRS scores. The administration of G-CSF appears to be safe and well tolerated. Further studies need to be done on a large sample to verify or fully characterize the results.

Coaxial electrospinning is a robust technique for one-step encapsulation of fragile, water-soluble bioactive agents, including growth factors, DNA and even living organisms, into core-shell nanofibers. The coaxial electrospinning process eliminates the damaging effects due to direct contact of the agents with organic solvents or harsh conditions during emulsification. The shell layer serves as a barrier to prevent the premature release of the water-soluble core contents. By varying the structure and composition of the nanofibers, it is possible to precisely modulate the release of the encapsulated agents. Promising work has been done with coaxially electrospun non-woven mats integrated with bioactive agents for use in tissue engineering, in local delivery and in wound healing, etc. This paper reviews the origins of the coaxial electrospinning method, its updated status and potential future developments for controlled release of the class of fragile, water-soluble bioactive agents.

LiFePO 4 samples with preferred facets on the ac plane were prepared by the solvothermal method with or without well-dispersed amphiphilic carbonaceous material (ACM). The effects of ACM on the particle morphology, crystal orientation and electrochemical reactivity of the prepared LiFePO 4 nanoparticles were investigated in detail. ACM serves a dual purpose. One purpose is facilitating the plate-like morphologies of LiFePO 4 nanoparticles parallel to the b Pnma axis by decreasing the surface energy of (010) facets of newly created LiFePO 4 nuclei. The other purpose is suppressing crystal growth along the [010] direction by adhering onto the (010) surface of LiFePO 4 nanoplates. Furthermore, ACM coating was performed and optimized using a carbon coating precursor. The electrochemical properties of the prepared LiFePO 4 particles were characterized by cyclic voltammetry (CV) and galvanostatic charge–discharge cycling tests. After the optimized coating of ACM, the ACM-intervened LiFePO 4 composite was observed to deliver discharge capacities of 151.3 mAh g −1 at 1C and 132.2 mAh g −1 at 10C. Even after 1000 cycles at a high rate of 10C, the LiFePO 4 cathode could maintain 80% of its initial capacity.

A novel approach to design pH-sensitive and disintegrable polyelectrolyte nanogels composed of citraconic-based N-(carboxyacyl) chitosan (polyanion) and quaternary chitosan (polycation) was reported. Firstly, the hydrolysis of citraconic-modified chitosan was monitored using fluorescamine assay and it could selectively dissociate in acidic media (e.g., pH ∼5.0) due to the isomerization during the addition of citraconic anhydride to chitosan. Secondly, the self-assembly behaviors of different polyelectrolyte pairs between citraconic-based chitosan and quaternary chitosan were investigated via colloidal titration assay. It was indicated that the difference in molecular weight (MW) of opposite charged polyelectrolytes played an important role on the formation of polyelectrolyte nanogels. Results showed that polyelectrolyte nanogels (ca. 300nm in size) only formed when polyanion and polycation had a very large difference in MW. The pH-sensitive behavior of polyelectrolyte nanogels was comprehensively investigated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The incorporation of charge-conversional citraconic-based chitosan into polyelectrolyte complexes has provided an effective approach to prepare polyelectrolyte nanogels which were very stable at neutral pH but disintegrated quickly in acidic media.

In this study, thermochemical biomass and coal co-gasification were performed on an autothermal fluidized bed gasifier, with air and steam as oxidizing and gasifying media. The experiments were completed at reaction temperatures of 875 °C–975 °C, steam-to-biomass ratio of 1.2, and biomass-to-coal ratio of 4. This research aims to determine the effects of reaction temperature on gas composition, lower heating value (LHV), as well as energy and exergy efficiencies, of the product gas. Over the ranges of the test conditions used, the product gas LHV varies between 12 and 13.8 MJ/Nm 3 , and the exergy and energy efficiencies of the product gas are in the ranges of 50.7%–60.8% and 60.3%–85.1%, respectively. The results show that high reaction temperature leads to higher H 2 and CO contents, as well as higher exergy and energy efficiencies of the product gas. In addition, gas LHV decreases with temperature. The molar ratio of H 2 /CO is larger than 1 at temperatures above 925 °C. Our experimental analysis shows that co-gasification of biomass and coal in an autothermal fluidized bed gasifier for gas production is feasible and promising.

Three model drugs with different function groups were chosen to dialyze with dextran-graft-poly (N-isopropylacrylamide). Only ibuprofen could induce the formation of drug loaded micelles, which was confirmed with dynamic light scattering and transmission electron microscope. Hydrogen-bonding between the amide groups of poly (N-isopropylacrylamide) and the carboxyl groups of ibuprofen was driving force for the drug-loaded micelle. It was also found that the diameter of the ibuprofen-loaded micelles changed reversibly against temperature.

A model comprises two sub-models, i.e. combustion and gasification models, is developed to simulate a single fluidized bed two-step gasification process and to predict H 2 production under different conditions. The combustion sub-model which consists of volatile precipitation and char combustion sub-models. The combustion sub-model is used to forecast residual char. The gasification sub-model, based on the mass and energy balance, is used to examine thermodynamically the effect on the hydrogen production of calcium oxide as the catalyst. Moreover, the effects of the operational conditions on the hydrogen production such as biomass/coal (mass ratio), temperature, steam/coke, and calcium/coke, are simulated. The results indicate that the addition of calcium oxide at certain conditions can significantly improve hydrogen production and lower the required temperature for gasification. The model predicts that the maximum hydrogen production of 60% can be achieved under the conditions of temperature in the range of 800–850 °C, calcium/coke, steam/coke, and coal/biomass (mass ratio) are 0.5, 1.8, and 1/4, respectively. The model predictions are in good agreement with the experimental data.

The influence of loading indomethacin (IMC) on the thermosensitive aggregation of a double hydrophilic graft copolymer dextran-graft-poly(N-isopropylacrylamide) (DgP) was studied. Before IMC-loading, DgP forms loose aggregates of unimers in aqueous solution below the lower critical solution temperature (LCST), while compact nanoparticles appear above the LCST because of the phase transition of the poly(N-isopropylacrylamide) (PNIPAAm) side chains (Topp, 1997 [31]; Motokawa, 2005 [32]; Zhao, 2006 [25]). After the loading of IMC, however, uniform nanoparticles were formed even below the LCST. The hydrogen bonding between IMC and the PNIPAAm side chains is proposed as the driving force for the aggregation. The IMC release rate was accelerated at a higher temperature because of the dissociation of the hydrogen bonds.

An ammonia-oxidizing strain of Penicillium sp., M25-22 which was isolated from chicken feces compost, was studied to make clear its characteristics of ammonium oxidation and provide References for its application in aerobic composting. In media containing (NH4)2SO4 at a concentration of 0.5 g 100 mL-1, mycelium weight and utilization ratio of ammonium nitrogen increased markedly during the 1st 5 d, concentration of nitrate increased markedly from the 3rd to the 5th d and concentration of nitrite remained at a low level. The strain showed the ability to oxidize ammonium nitrogen growing in media containing glucose, sucrose, starch, or cellulose as the sole carbon source and to oxidize the negative trivalent nitrogen of ammonium sulfate, peptone, acetamide, urea, or L-aspartate. Slowly available carbon or nitrogen sources such as starch, cellulose, and peptone were beneficial to ammonium oxidation. In media containing sucrose as the sole carbon source and ammonium sulfate as the sole nitrogen source, nitrate formation was the most pronounced with sucrose present at a concentration of 12 g L-1 and ammonium nitrogen present at a concentration of 2.438 mg mL-1, at the initial pH level of 7.5 and at 30°C.

A novel pH-responsive hydrogel (CHC) composed of N-carboxyethyl chitosan (CEC) and N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) was synthesized by the redox polymerization technique. Turbidimetric titrations were used to determine the stoichiometric ratio of these two chitosan derivatives. The hydrogel was characterized by FT-IR, thermal gravimetric analysis (TGA), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The dynamic transport of water showed that the hydrogel reached equilibrium within 48 h. The swelling ratio of CHC hydrogel depended significantly on the pH of the buffer solution. The performance of the CHC as a matrix for the controlled release of BSA was investigated. It was found that the release behavior was determined by pH value of the medium as well as the intermolecular interaction between BSA and the hydrogels.

A facile strategy was proposed for synthesizing chitosan-O-poly(e-caprolactone) (CS-O-PCL). Stoichiometric sodium dodecyl sulfate–chitosan complex (SCC) which was soluble in common organic solvents was adopted as an intermediate. Regioselective conjugation of PCL onto SCC could be achieved through condensation reaction between isocyanate-terminated PCL and hydroxyl groups of chitosan. The grafting level of PCL could be modulated by varying PCL/SCC weight ratio. SDS was removed from SCC-O-PCL using trihydroxymethylamine (Tris) as a decomplexation agent. The self-assemble behavior of the amphiphilic copolymers was studied by fluorometry, TEM and laser light scattering. The morphology of the CS-O-PCL nanoparticles was found to be dependent on PCL grafting level. Both spherical micelles and vesicle could be formed by dialysis method.

Coaxial electrospinning was proved to be a facile method to produce multifunctional fibrous matrices which could essentially emulate certain features of native extracellular matrix. In order to further confer capability of immobilizing diverse macromolecular bioactive agents to the fibers, composite membranes composed of cationized gelatin-coated polycaprolactone (PCL) fibers were prepared by coaxial electrospinning. Gelatin was cationized by derivation with N,N-dimethylethylenediamine. The cationized gelatin (CG) was used as a shell material for constructing a core-shell fibrous membrane. PCL formed the core section of the core-shell fibers thereby improving the mechanical properties of nanofibrous CG hydrogel. The outer CG layer was crosslinked by exposing the membranes in glutaraldehyde vapor. The adsorption behaviors of FITC-labeled bovine serum albumin (FITC-BSA) or FITC-heparin onto the fibers were investigated. The core-shell fibers could effectively immobilize the two types of agents under mild conditions. The adsorption amount could reach about 12 microg of BSA per mg of membrane and 23 microg mg(-1) for heparin. Furthermore, vascular endothelial growth factor (VEGF) could be conveniently impregnated into the fibers through specific interactions with the adsorbed heparin in the outer CG layer. Sustained release of bioactive VEGF could be achieved for more than 15 days.

Biofeedback is an acquisition technique of self-regulation ability of an autonomic function, of which we are normally unaware, through a series of training aided by an additional outer feedback pathway. We proposed a mathematical model of biofeedback in which a learning system on the conscious level learns characteristics of a subconscious regulation system corresponding to the biological function. When the learning converges, the learning system itself becomes an inverse system of the regulation system. Then, if a regulation command is put to the learning system on the conscious level, it drives the regulation system strictly following the command without the outer feedback pathway, which enables voluntary control of the biological function.

Copolymers of starch grafted with poly (lactic acid) were directly prepared by in situ reaction of cornstarch with lactic acid in aqueous media in the presence of stannous 2-ethyl hexanoate [Sn(Oct)2]. The procedure of the graft reaction was elucidated, based on the HPLC analysis, as the ring-opening polymerization (ROP) from starch surface of the small amounts of lactide produced in situ in the reaction system. The detailed chemical microstructure of the resultant graft copolymer was clarified by one- and two-dimensional NMR spectroscopy. Analysis of 13C NMR spectra of the carbons in starch ring as well as the carbonyl carbons in LA moiety demonstrates that the reactivity of hydroxyl groups at glucopyranan unit of starch decreases in the order of C-6>C-3>C-2. The average length of PLA grafts at individual starch ring carbons was also investigated.

Green needle coke was oxidized by a mixture of HNO 3 and H 2 SO 4 (3:7 vol/vol) acids. The resultant oxidized coke was separated into water dispersible and non-dispersible fractions, which were then activated by KOH using the same KOH/coke weight ratio to obtain two kinds of nanoporous carbons with different pore structures. The oxidized coke and the nanoporous carbons were characterized by XPS, XRD, TEM, N 2 adsorption and electrochemical tests. Results indicate that, at the same KOH/coke ratios, the nanoporous carbons derived from the water-dispersible oxidized coke have higher mass specific capacitances and capacitance retention ratios, and lower resistances than those from the non-dispersible ones when used as an electric double layer capacitor electrode in 6 M KOH, but the former have a lower volumetric specific capacitance than the latter. [New Carbon Materials 2015, 30(2): 141–149]