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English differs from other languages in morphology, which may cause trouble in EFL learning. The interesting topic is whether ESL learners can obtain the same level of morphology in their English learning as native English speakers. The study explores whether high-proficiency EFL learners differ from native EL1 learners in writing using root words, inflected words, and derived words. This article reported on a comparative study between Advanced EFL learners (TOEFL Testees (n = 318)) and native English learners (writers of the Louvain Corpus of Native English Essays (n = 176)) by lexical frequency profile analysis on their use of root words, inflected words, and derived words in writing. The findings suggest that there are significant differences between the two groups. TOEFL writers used a much higher proportion of root words but a much lower proportion of inflected and derived words than native English learners. The findings will expose the differences between EFL learners and native L2 learners in word learning and contribute to L2 language teaching and learning theoretically and practically. [ABSTRACT FROM AUTHOR]

A biocatalyzed artificial photosynthesis system (APS) based on porphyrin/SiO2/Cp*Rh(bpy)Cl hybrid nanoparticles (TCPP/SiO2/Rh HNPs) to mimic chloroplasts in green plant is reported. The TCPP/SiO2/Rh HNPs are fabricated via sol-gel reaction of silica precursors functionalized with photosensitizer (porphyrin, TCPP) and electron mediator (Cp*Rh(bpy)Cl, M); while the integration of enzyme and coenzyme nicotinamide adenine dinucleotide (NAD)(H), on the outer surface of the HNPs is achieved through electrostatic- interaction-driven assembling under the entanglement of a negatively charged polyelectrolyte. The chloroplast-mimicking, highly integrated APS exhibits remarkably superior performance over a free system such that the regeneration of NADH is improved from 11% to 75%, and the synthesis of formic acid from CO2 increased from 15 to 100 μmol. Based on the detailed investigations into the photochemical and electrochemical properties, it is speculated that the covalent linking of the photosensitizer and electron mediator via silicon hydride bonds, and the formed SiO2 network through sol-gel reaction, may form intramolecular and intermolecular electron transfer chains to direct more efficient electron transfer from TCPP to M. Such intramolecular and intermolecular electrons and energy transfer, cooperated with the integrated biocatalytic process, lead to the significantly enhanced overall reaction efficiency. Moreover, the integrated APS also allows facile recycling of expensive M, enzymes, and cofactors. [ABSTRACT FROM AUTHOR]

The inactivation of photosensitizers before they reach the targeted tissues can be an important factor, which limits the efficacy of photodynamic therapy (PDT). Here, we developed co-assembled nanohybrids of graphene oxide (GO) and albumin/photosensitizer that have a potential for protecting the photosensitizers from the environment and releasing them in targeted sites, allowing for an enhanced PDT. The nanohybrids were prepared by loading the pre-assembled nanoparticles of chlorin e6 (Ce6) and bovine serum albumin (BSA) on GO via non-covalent interactions. The protection to Ce6 is evident from the inhibited fluorescence and singlet oxygen generation activities of Ce6-BSA-GO nanohybrids. Importantly, compared to free Ce6 and Ce6 directly loaded by GO (Ce6-GO), Ce6-BSA-GO nanohybrids showed enhanced cellular uptake and in vitro release of Ce6, leading to an improved PDT efficiency. These results indicate that the smart photosensitizer delivery system constructed by co-assembly of GO and albumin is promising to improve the stability, biocompatibility, and efficiency of PDT. [ABSTRACT FROM AUTHOR]

Gigaporous poly(styrene-divinyl benzene) microspheres made via the surfactant reverse micelles swelling method had a controllable pore size of 100-500 nm. These microspheres had unique advantages in biomacromolecule separation and enzymes immobilization. However, the obtained microspheres adhered to each other in the preparation process. Though the weak aggregation could be re-dispersed easily by mechanical force, it will be difficult to scale up. By analyzing the formation mechanism of the aggregates, a method was presented to rebuild the interface between the internal aqueous channel and the external continuous phase by constructing an aqueous two-phase system (ATPS). Based on the ATPS, the method of emulsification, stirring speed, and surfactant concentration in oil phase were optimized. Under the optimum condition (screen emulsification method, 120 rpm for polymerization and 55% surfactant), the microspheres with a controllable particle size of 10-40 m and a pore size of about 150 nm were obtained. This new method could significantly decrease the weak-aggregation of microspheres. [ABSTRACT FROM AUTHOR]

Compared with the one immobilized in the conventional mesoporous microspheres, the enzyme immobilized in gigaporous microspheres showed much higher activity and better stability. To gain a deeper understanding, we herein selected lipase as a prototype to comparatively analyze the adsorption behavior of lipase at interfaces in gigaporous and mesoporous polystyrene microspheres at very low lipase concentration, and further compared with the adsorption on a completely flat surface (a chip). Owing to the limited space of narrow pores, lipase molecules were inclined to be adsorbed as a monolayer in mesoporous microspheres. During this process, the interaction between lipase molecules and the interface was stronger, which could result in the structural change of lipase molecular and compromised specific activity. In addition to monolayer adsorption, more multilayer adsorption of enzyme molecules also occurred in gigaporous microspheres. Besides the adsorption state, the pore curvature also affected the lipase adsorption. Due to the multilayer adsorption, the excellent mass transfer properties for the substrate and the product in the large pores, and the small pore curvature, lipase immobilized in gigaporous microspheres showed better behaviors. [ABSTRACT FROM AUTHOR]

Uniform small-sized (<10 μm) Konjac glucomanna (KGM) microspheres have great application prospects in bio-separation, drug delivery and controlled release. Premix membrane emulsification is an effective method to prepare uniform small-sized KGM microspheres. However, since KGM solution bears strong alkalinity, it requires the membrane to have a hydrophobic surface resistant to alkali. In this study, uniform small-sized KGM microspheres were prepared with epoxy-based polymer membrane (EP) we developed by premix membrane emulsification. It was found that emulsion coalescence and flocculation occurred frequently due to the high interface energy and sedimentation velocity of KGM emulsions. Emulsion stability had a significant influence on the uniformity and dispersity of the final KGM microspheres. To improve the stability of the emulsions, the effects of the concentration of the emulsifier, the viscosity of the KGM solution, the oil phase composition and the feeding method of epoxy chloropropane (EC) on the preparation results were studied. Under optimal preparation conditions (emulsifier 5 wt % PO-5s, KGM III (145.6 mPa· s), weight ratio of liquid paraffin (LP) to petroleum ether (PE) 11:1), uniform and stable KGM emulsions (d = 7.47 μm, CV = 15.35%) were obtained and crosslinked without emulsion-instable phenomena. [ABSTRACT FROM AUTHOR]

Pickering emulsions stabilized by solid particles have been widely studied in the past decades due to improved stability and reduced use of small molecular surfactants. Recently, the application of Pickering emulsions in pharmaceutics has been attracting increasing attention but very limited practical use has been demonstrated, because most of the investigated particles possess poor biodegradability, which is inappropriate in pharmaceutics. Some reported biodegradable particles were too hydrophilic to stabilize emulsions, which needs further particle modification or additional surfactants. Fortunately, biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) with tunable hydrophilicity makes itself a promising material to prepare Pickering emulsions. However, the mechanism of emulsion stabilization still remains unknown. Moreover, fabrication of large amounts of uniform-sized and size-controlled PLGA particles by traditional methods is very difficult, which further increases the difficulty to perform the research. In the present study, we applied Shirasu Porous Glass (SPG) premix membrane emulsification to solve this problem. The stabilization mechanism of Pickering emulsions stabilized by PLGA particles was systematically studied for the first time. The factors including oil type, particle properties, concentration, molecular weight (Mw) and oil-water volume ratio were analyzed through particle wettability and interfacial influence. We found that octanol was an appropriate oil type, and its small particle size, high particle concentration and high Mw were favorable for emulsion stability. By changing the oil-water volume ratio, stable emulsions were also readily achieved. These studies proved that Pickering emulsions stabilized by PLGA particles had wide potential applications in pharmaceutics and tissue engineering. [ABSTRACT FROM AUTHOR]

Colloidosomes are microcapsules that consist of a hollow core coated by a shell composed of self-assembled colloidal particles. In recent years, they have attracted significant attention as potential vehicles for the controlled delivery of active ingredients. A key challenge in such applications is the production of uniform-sized colloidosomes for the encapsulation of active ingredients such that the actual delivery amount can be well controlled. Based on our previous study on an ethyl acetate-in-water emulsion stabilized by chitosan-coated alginate particles, we further prepared monodisperse colloidosomes with a high yield and low permeability by combining the premix membrane emulsification technique and polymer deposition method. The potential application of the formed colloidosomes as oral insulin delivery vehicles was investigated. Our results revealed that in comparison to conventional PLGA microspheres, the formulated colloidosomes showed high drug encapsulation efficiency (up to 96.7%) and an obvious pH sensitive release profile. Moreover, in animal testing, the colloidosomes formulation achieved a long-term hypoglycemic effect up to 6 h, which confirmed its application as an oral drug delivery system. [ABSTRACT FROM AUTHOR]

In this study, a polymeric lipid nanoparticle (NP) (simplified as Lipid NP) was reported as a promising oral vaccine delivery system. The Lipid NPs composed of a hydrophobic polymeric poly(D,L-lactide-co-glycolide) (PLGA) core and a surface coating of lipid monolayer. Membrane emulsification technique was used to obtain uniform-sized Lipid NPs. Ovalbumin (OVA) was used as a model vaccine. Compared with the pure PLGA NPs, the Lipid NPs achieved higher loading capacity (LC) and entrapment efficiency (EE) for the encapsulated OVA. An in vitro oral release profile showed that the OVA-Lipid NPs were with lower initial burst and could protect the loaded OVA from the harsh gastrointestinal (GI) environment for a long time. In addition, a human microfold cell (M-cell) transcytotic assay demonstrated that due to a lipid layer structure on the particle surface, the Lipid NPs showed higher affinity to the M-cells. Since the M-cell in the intestinal epithelium played an important role in particle transportation as well as intimately associated with the underlying immune cells, the OVA-Lipid NPs effectively induced mucosal and humoral immune responses. [ABSTRACT FROM AUTHOR]

Highly efficient immobilization of multi-enzyme systems involving cofactor regeneration represents one of the greatest challenges in bioprocessing. Particulate artificial cells with enzymes and cofactors encapsulated within microcapsules have long been the major type of multi-enzyme biocatalysts. In the present work, a novel hollow nanofiber-based artificial cell that performs multi-step reactions involving efficient coenzyme regeneration was fabricated in situ by a facile co-axial electrospinning process. To that end, a mixture of glycerol and water containing the dissolved multi-enzyme system for the bile acid assay, which included 3α-hydroxysteroid dehydrogenase (3α-HSD), diaphorase (DP) and NADH was fed as the core phase solution, and a N,N-dimethylacetylamide solution of 30 wt% polyurethane was fed as the shell phase solution during the co-axial electrospinning. The relationship between the structures of the hollow nanofibers and the activity and stability of the encapsulated enzymes was studied. At core and shell phase electrospinning solution flow rates of 0.07 and 0.5 mL h[sup -1] activity recoveries as high as 76% and 82% were obtained for the encapsulated 3α-HSD and DP. The hollow nanofiber-based artificial cells were successfully used for the bile acid assay, yielding good linearity for bile acid concentrations ranging from 0-200 µM. Compared with the solution-based multi-enzyme system, the hollow nanofiber-based multi-enzyme system presented a lumped activity recovery of 75%. In addition, the hollow nanofiber provided the multi-enzyme system confined inside the nano-domain of the hollow fibers with a unique stabilizing mechanism, such that more than a 170-fold increase in half-life at 25 °C was obtained for the encapsulated 3α-HSD and DP. This study is expected to greatly promote and broaden the application of multi-enzyme systems in industry, biosensor, biomedical, and many other related research fields. [ABSTRACT FROM AUTHOR]

A comparison has been made of productive vocabulary in some normal university English majors' theses in China and American final-year undergraduates' papers. The research demonstrates that with family as the measurement unit, Chinese students proportionally use fewer words of the 1st, 8th to 10th 1000 frequency level words than American students, while in terms of the 2nd to 4th 1000 frequency band words, Chinese students use more than American students and there is no difference in the usage of the words of the rest word lists. In terms of lexical words complexity: American students repeatedly use the 1st 1000 high-frequency words in a higher proportion, use more inflectional forms than Chinese students but use fewer derivational forms than Chinese students. Chinese students use the 2nd 1000 frequency band words repeatedly in a greater proportion than American students; use more inflectional and derivational forms than American students. Chinese students use low-frequency words repeatedly in a greater proportion, more inflectional forms, but use the derivational forms in the same proportion as American students. [ABSTRACT FROM AUTHOR]

Apoferritin-encapsulated Pt nanoparticles (AFt–Pt) were bio-mimetically prepared by an in situreduction method in the unique 8 nm spherical cage of apoferritin. The average size of AFt–Pt was 4.3 ± 0.9 nm. The spherical structure of apoferritin remained intact after loading Pt particles in its cavity. Apoferritin coating increased the amount of Pt internalized in HepG2 cells by about three times viareceptor-mediated endocytosis. AFt–Pt showed greatly improved biocompatibility compared with polyvinylpyrrolidone stabilized Pt nanoparticles (PVP–Pt). More than 80% of cells survived after treatment with 100 μM AFt–Pt for 48 h. By camouflaging the particles with a protein corona, apoferritin conferred a cell-recognizable identity to the particles, which strikingly ameliorated the bio-effects of the nanoparticles. [ABSTRACT FROM AUTHOR]

Carboxylmethylated konjac glucomannan (CKGM) is a carboxylmethylated polymer of mannose and glucose that is derived from the plant Amorphophallus konjac cultivated in East Asia. The CKGM solution had a high volume-expanding efficacy and was evaluated as a plasma substitute in the present study. Ameliorative hemorrhagic shock rabbits were used as the model animals. The in vivo hemodynamic and hemorheologic properties, including blood pressure, blood viscosity, hematocrit, erythrocyte deformation index and erythrocyte aggregation index, were measured in animals treated in the CKGM solution. The in vitro colloid osmotic pressure (COP) of the CKGM solution was measured to estimate its plasma-expanding efficacy. These parameters of the CKGM-treated group were compared with groups exposed to four other treatments: human serum albumin (HSA), hydroxyethyl starch (HES), polygeline and normal saline. The CKGM solution showed an exceptionally higher COP than other therapy solutions. For example, the COP of 1% (weight in volume [w/v]) CKGM solution is comparable to those of 6% (w/v) HES solution and 5% (w/v) HSA solution. Accordingly, the CKGM solution can be transfused in a much lower dosage while maintaining its plasma-expanding efficacy. The CKGM-treated group showed an improved intravascular persistence and good hemodynamic and hemorheological properties. Biopsy analysis suggested no organ dysfunction in the group treated in CKGM solution. Moreover, the high plasma-expanding efficacy and inexpensive availability of the CKGM solution may facilitate its clinical application as a potential plasma substitute. [ABSTRACT FROM PUBLISHER]

A solid-phase adsorption method was developed to circumvent the disadvantage of the conventional liquid-phase PEGylation, i.e. the heterogeneity of the PEGylated products. The model proteins, human serum albumin (HSA) and staphylokinase (SAK), were adsorbed on the ion exchange chromatography media, followed by PEGylation with succinimidyl carbonate (SC)-mPEG5K and salt elution. Since PEGylation with SC-PEG5K alters the positive charge of the proteins, Q-Sepharose Big Beads and DEAE Sepharose Fast Flow were used for adsorption of HSA and SAK, respectively. Size exclusion chromatography and SDS-PAGE studies demonstrated that solid-phase PEGylation of proteins generate monoPEGylated proteins with the yield of 35–47%. Circular dichroism and intrinsic fluorescence studies showed that solid-phase PEGylation led to little conformational change of the proteins. Solid-phase PEGylation resulted in 35% loss in the biological activity of SAK, which is lower than the liquid-phase PEGylation (70%). [ABSTRACT FROM AUTHOR]

Porous poly(2‐hydroxyethyl methacrylate‐co‐ethylene dimethacrylate) [p(HEMA‐co‐EDMA)] microspheres have important applications in chromatography. In this study, p(HEMA‐co‐EDMA) microspheres with controllable size were successfully prepared by modified membrane emulsification technique. The CV value of the obtained microspheres was as low as 14.4%. An oil phase mainly composed of toluene was permeated through a membrane with uniform pores into an aqueous phase to form fairly uniform seed emulsion. The secondary emulsion composed of HEMA and EDMA was prepared by a homogenizer. Then, the two emulsions were mixed together. HEMA and EDMA diffused into the aqueous phase, and then were absorbed by the seed droplets. The swollen droplets were further polymerized to prepare monodisperse porous microspheres. It was found that HEMA/EDMA ratio and toluene/monomer ratio showed a significant influence on swelling degree, diameter, and morphology of the obtained microspheres. The swelling degree of the microspheres increased with the increase of toluene/monomer ratio, whereas the average diameter increased with decrease of the ratio. Microspheres with controllable size (28–73 μm) and porosity were obtained, by varying HEMA/EDMA ratios and toluene/monomer ratios. It can be expected that the p(HEMA‐co‐EDMA) microspheres with controllable size and porosity will provide many advantages in their applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 [ABSTRACT FROM AUTHOR]

Poly(N-isopropylacrylamide) (PNIPAM) and random copolymers of Poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (PNIPAM-HEMA), poly(N-isopropylacrylamide-co-acrylamide) (PNIPAM-AAm), and poly(N-isopropylacrylamide-co-N,N-dimethylacrylamide) (PNIPAM-DMAA) with various volume fractions γ of NIPAM were synthesized by radical polymerization. The phase behavior of the polymers in water was investigated by means of optical transmittance and dynamic light scattering. With decreasing γ, the cloud point temperature Tcp for PNIPAM-HEMA decreased whereas the Tcp for both PNIPAM-AAm and PNIPAM-DMAA increased. Increase of hydrodynamic radius around Tcp, which resulted from the aggregation of the globules of each polymer, was observed from dynamic light scattering. The relationships between the reciprocal of Tcp of the polymer solutions and 1-γ were linear for the three copolymers in the experimental range of 0.65<γ<1. The results are discussed from the aspect of the interaction parameters of copolymer solutions. [ABSTRACT FROM AUTHOR]

A novel methoxypolyethylene glycol (mPEG) derivative, containing a reactive group of 1-methyl pyridinium toluene-4-sulfonate, was synthesized and characterized. The mPEG derivative was successfully conjugated with two proteins: recombinant human granulocyte-colony stimulating factor (rhG-CSF) and consensus interferon (C-IFN). Homogeneous mono-PEGylated proteins were obtained which were identified by high performance size-exclusion chromatography and MALDI-TOF mass spectrometry. The biological activities of the mono-PEGylated rhG-CSF and the mono-PEGylated C-IFN were maintained at 90% and 88%, respectively. [ABSTRACT FROM AUTHOR]

An efficient low-pressure preparative chromatography for purification of icariin from crude extract has been developed by employing a novel uniform porous microsphere, named PST, as packing material. A comparison was made between the PST medium and a commercially available silica-based C18 medium on their column chromatographic performance. The PST column demonstrated a higher resolution and better selectivity than the C18 column. Crude extract of 20% icariin can be purified to 90.0% with the recovery of 99.9% and column loadability of 2.5 mg·mL−1 medium on the PST column under the optimized condition. After crystallization the purity of icariin can reach more than 98% with a total recovery of 93%. The product structure was determined by means of UV, IR, MS and NMR. [ABSTRACT FROM AUTHOR]

A novel tetrafunctional reagent, a,?,a',?'-tetra-succinimidyl-hexanediamide-di-glutamate ester (HDG(OSu)4), was successfully synthesized, and a well-defined cross-linked bovine hemoglobin (mainly 128 kDa) was prepared with this reagent. Due to the spatial structure of this cross-linking reagent, the intramolecular and intermolecular cross-linking of bovine hemoglobin was formed simultaneously in one reaction. Although the cross-linked bovine hemoglobin showed a slight decrease in half-saturated O2 pressure value (P50, from 28.1 mm Hg to 21.7 mm Hg) and Hill coefficient (from 2.5 to 2), due to the cross-linkage, it still performed well for O2 delivery. [ABSTRACT FROM AUTHOR]

A new process for preparation of magnetic microspheres was investigated. In this process, the formation and the encapsulation of magnetic nanoparticles were accomplished in one step. The magnetic polymer microspheres exhibited superparamagnetic property and had a spherical shape with a smooth surface. This method can be used to prepare inorganic and organic composite particle when the inorganic particles can be prepared by chemical coprecipitation reaction. [ABSTRACT FROM AUTHOR]