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The article discusses a study that predicted the crystal growth morphology of benzoic acid. Topics covered include the systematic consideration of solvent effects using the modified attachment energy (AE) model, the controlling effect of solvent interaction with growing crystals on crystal aspect ratio, and the observed crystal morphologies in a range of different solvents.

A novel separation mode of isotachophoresis (ITP) was advanced for the study on the continuous moving chelation boundary (MCB) formed with EDTA and two metal ions of Co(ii) and Cu(ii). The experiments were performed systemically. The relevant results indicated that: (1) there were three boundaries in the whole system, viz., a sharp MCB, a wide moving substitution boundary (MSB) and a sharp complex boundary (CB); (2) within the MSB, an ion substitution reaction occurred between [Co-EDTA]2−and Cu(ii), and the reaction resulted in the release of Co(ii) and EDTA from [Co-EDTA]2−and the binding of Cu(ii) with the released EDTA due to log KCu(ii)(= 18.80) > log KCo(ii)(= 16.31); (3) because of the novel ITP mode induced by the MSB as well as the merging of the MCB and CB, the original low concentration Co(ii) and Cu(ii) were chemically separated as two characteristic coloured zones of pink [Co-EDTA]2−and blue [Cu-EDTA]2−, and the sensitivities for detection of the two metal ions were greatly enhanced. The quantitative analyses of the zone composition by ICP-AES and UV-vis spectrophotometry supported the mechanism of the novel separation mode induced by the MSB. The further theoretical and experimental results indicated that the separation mode was a novel ITP relied on moving reaction boundary (MRB), rather than a classic ITP based on the moving boundary system developed about 60 years ago. These findings provide guidance for the development of the MRB and the MCB-based ITP separation of metal ions in environmental and biological matrices. [ABSTRACT FROM AUTHOR]

Abstract  A centrifugal model test was performed to investigate the behavior of a geogrid-reinforced embankment on a 20 m thick soft silty clay subsoil. The lime-stabilized soil embankment was 4 m high, 26 m wide with slopes of 1:1.5 and included sand wick drains. Displacements, earth pressures and pore water pressures were measured during the test. Test results showed settlement on the front face of the foundation was approximately 90% of that measured by displacement sensors; the elastic displacement was approximately 11% of the total displacement; and the reinforced embankment remained serviceable despite a 300 mm wide crack on the embankment surface and up to 1.73 m settlement at the centerline of the embankment. [ABSTRACT FROM AUTHOR]

The spectra of a charged harmonic oscillator minimally coupled to a perpendicular magnetic field in the non-commutative plane are studied by using the path integral formulation. We get the spectra in a mapping-independent way. Interestingly, we find that the spectra have no continuous limit when the dimensionless parameter tends to zero. In order to get a finite result, a truncation is inevitable. Finally, we give a reasonable explanation of truncation from the constrained theory point of view. [ABSTRACT FROM AUTHOR]

Using a capillary video-microscopy technique, the formation of ZrO2precursors with the two reverse-emulsion precipitation method was visually studied by preparing the reverse W/O emulsions within a thin-walled, transparent, cylindrical microtube. Two types of aqueous droplets, i.e., one containing ZrO(NO3)2solution and the other containing ammonia solution, were prepared in the oil phase to produce ZrO2precursors. It was found that the ZrO2precursors could hardly be formed by the coalescence of the emulsion droplets, even if they were in contact with each other. Instead, the formation of ZrO2precursors was mainly induced by ammonia diffusion across the oil phase. Interestingly, the growth of ZrO2precursors did not occur within any of the prepared aqueous droplets, which are generally considered to be space-limiting microreactors, as expected from much previous research. The ZrO2precursors were mostly formed by the distortion and split of the aqueous droplets containing ZrO(NO3)2solution. Increased surfactant content in the oil phase slowed the formation of the ZrO2precursors, probably due to the increased viscosity, which can hinder the distortion and split of the aqueous droplets. In addition, the growth of ZrO2precursors was also retarded by the increase of the size of the aqueous droplets. [ABSTRACT FROM AUTHOR]

The purpose of this study was to prepare ultrafine beclomethasone dipropionate (BDP) powder via antisolvent precipitation without any surfactants. Various solvents were screened to determine the suitable system for optimum processing while deionized water was kept as the antisolvent. Methanol was selected as the solvent, because a higher degree of supersaturation could be achieved. Several experimental parameters, such as the volume ratio of solution to antisolvent, the concentration of BDP−methanol solution, the temperature, and the stirring speed and time, were investigated in the methanol−deionized water system. The results showed that the yielded powder had a mean particle length of 850 nm and 85% of the particles were distributed in the range of 0.2−1.2 m, whereas the raw particle size was 2.13 m, ranging in size from 0.2 m to 12 m. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis indicated no change in chemical group structure and crystal structure during the process. In addition, a process recovery rate of >99.99% was obtained. [ABSTRACT FROM AUTHOR]

Suggests that the CP1 domain in Escherichia coli leucyl-transfer RNA (tRNA) synthetase is crucial to the second editing sieve. Need for a structural context in leucyl-tRNA synthetase for fulfillment of CP1 editing function; Implication of the ability of LeuRS-B in catalyzing mischarges of tRNA for CP1 editing function; Misaminoacylation of tRNA.

The correlation function of the echo signal intensities at a fixed region on a series of B-mode images is directly related to the change of speckle patterns between these images. An indication is given here of how the rate of the change of that correlation function can be used to estimate the scan-plane motion in any direction relative to the imaged tissue or other material. In this first implementation it is assumed that the statistical properties of the echo signals follow those of a complex circular Gaussian, and the case is considered of diffusely scattering tissue with many fine particles per resolution cell and with no phase distortion. The method is applied to data from a one-dimensional linear array and initial results are presented for scanning a tissue-mimicking phantom in the elevational direction of the transducer. Experimental results are in good agreement with the predictions. The current method should provide a good indication of the local rate of scan-head motion in those tissues in which the normalized correlation function of the echo signal intensities behaves, or can be made to behave, as it would for a medium with uniform acoustic properties and containing many, randomly distributed, pointlike scatterers, although application might be made to other situations where a deterministic condition exists for the correlation between images taken at differing locations within a volume. © 1997 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 8, 38–44, 1997 [ABSTRACT FROM AUTHOR]

By means of hybrid density functional theory (DFT) computations, we found that (Li,K)-codoped WO3 shows a significantly enhanced near-infrared (NIR) absorption ability for smart windows, and investigated the influence of doping through the analysis of the electronic structures of pure and doped hexagonal WO3. Furthermore, this codoped material, with a hexagonal tungsten bronze nanostructure, was successfully prepared via a simple one-step hydrothermal reaction for the first time. Transmission electron microscopy images showed that the as-prepared products possessed a nanorod-like morphology with diameters of about 5–10 nm. It was demonstrated that (Li,K)-codoped WO3 presents a better NIR absorption ability than pure, Li-monodoped or K-monodoped WO3, which is in good agreement with our theoretical predictions. The experiment and simulation results reveal that this enhanced optical property in NIR can be explained by the existence of high free electrons existing in (Li,K)-codoped WO3. [ABSTRACT FROM AUTHOR]

It is well-known that Cs+Re is an efficient dual-promoter in the Ag catalyzed ethylene epoxidation, but it is still necessary to develop more efficient dual-promoters to gain higher selectivity to ethylene oxide (EO). In this work, we investigate the ethylene epoxidation catalyzed by Cs+Re, Cu+Re and Cs+Cu dual-promoted Ag (111) and (110) surfaces by using density functional theory (DFT) calculations. The predicted selectivity of pure and dual-promoted Ag (111) surfaces for EO follows the order of pure Ag < Cs+Cu < Cs+Re < Cu+Re. In contrast, the order of pure Ag < Cs+Re < Cs+Cu < Cu+Re is predicted for the selectivity of pure and dual-promoted Ag (110) surfaces for EO. Our results show that Cu+Re dual-promoted Ag (111) and (110) surfaces could achieve a higher selectivity to EO, indicating that Cu and Re dual-promoted Ag catalysts could be potential and high-efficient for catalyzing the ethylene epoxidation reaction. [ABSTRACT FROM AUTHOR]

An organocatalytic asymmetric Michael addition reaction of 3-pyrrolyloxindoles to β-phthalimidonitroethene has been developed with a bifunctional thiourea-tertiary amine as the catalyst. A range of 3,3′-disubstituted oxindoles bearing contiguous 3,α,β-triamino functionality could be obtained in high yields with good diastereoselectivities and high enantioselectivities (up to 99% yield, 99:1 dr, and 98% ee). The higher reactivity of β-phthalimidonitroethene compared to the reactivity of ordinary nitroalkenes in the reaction with 3-pyrrolyloxindoles was demonstrated by contrast experiments. [ABSTRACT FROM AUTHOR]

In this work, external circulation rotating packed bed (EX-RPB) was combined with internal circulation rotating packed bed (IN-RPB) for the preparation of Y-type oxotitanium phthalocyanine nanocrystals (Y-TiOPc NCs) for the first time. The operating conditions in EX-RPB and in IN-RPB were investigated in detail. X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption spectroscopy analysis, and elemental analysis were performed, and xerographic properties were analyzed, to characterize the products. The experimental results indicated Y-TiOPc NCs with the average size of 6 nm were successfully prepared. The Q-band absorption peak of Y-TiOPc NCs centered at 782 nm, implying their potential application in the xerographic photoreceptors of laser printers. The photoreceptor fabricated with Y-TiOPc NCs exhibited an initial surface potential of 703.56 V, a photosensitivity of 0.166 μJ/cm², a residual potential of 26.48 V, and a dark decay rate of 10.64 V/s. This work made a significant improvement to control the crystal form of nanoparticles at a large scale. [ABSTRACT FROM AUTHOR]

The spectra and wave functions of the 2-dimensional harmonic oscillator in a noncommutative plane are revised by using the path integral formulation in coordinate space and momentum space, respectively. We perform the path integral formulation in coordinate space first. Then we study this problem in momentum space. The propagator is computed both in coordinate space and in momentum space. The modification due to noncommutativity of eigenvalues and eigenfunctions is studied. Both the small and large noncommutative parameter limits are discussed. [ABSTRACT FROM AUTHOR]

As an inorganic template for fabricating hollow silica nanotubes (SNTs), needle-like calcium carbonate particles consisting mainly of aragonite were obtained by carbonation in a high-gravity environment generated by rotating packed-bed reactor. Through orthogonally designed experiments, the optimal conditions for the fabrication of SNTs, i.e., reaction temperature (15 °C), SiO2/CaCO3ratio (20 wt %), and cetyltrimethylammonium bromide (CTBA)/CaCO3ratio (50 wt %), were obtained. The prepared SNTs were characterized by Brunauer−Emmett−Teller (BET) analysis, transmission electron microscopy (TEM), and scanning electron microscopy (SEM). A hollow nanotubular structure with open ends was revealed. The resulting SNTs were utilized as a support for the immobilization of glucose oxidase (GOx) by a simple physical adsorption method. FTIR spectra indicated that the protein secondary structure was maintained well in the immobilized molecules. The amount of protein immobilized on the SNTs and the enzymatic activity of the immobilized GOx were investigated in detail. It was observed that the enzymatic activity first increased and then decreased with increasing coverage of the SNT surface by GOx, indicating that the overlap and aggregation of GOx molecules can decrease the enzymatic activity of the adsorbed GOx molecules at high surface coverage. [ABSTRACT FROM AUTHOR]

The time integration method with four-order accuracy, self-starting and implicit for the diffuse chemical reaction kinetics equation or the transient instantaneous temperature filed equation was presented. The examples show that both accuracy and stability are better than Runge-Kutta method with four-order. The coefficients of the equation are stored with sparse matrix pattern, so an algorithm is presented which combines a compact storage scheme with reduced computation cost. The computation of the competitive and consecutive reaction in the rotating packed bed, taken as examples, shows that the method is effective. [ABSTRACT FROM AUTHOR]

Aquifex aeolicus αβ-LeuRS is the only known heterodimeric LeuRS, while Escherichia coli LeuRS is a canonical monomeric enzyme. By using the genes encoding A. aeolicus and E. coli LeuRS as PCR templates, the genes encoding the ct and β subunits from A. aeolicus αβ-LeuRS and the equivalent amino- and carboxy-terminal parts of E. coli LeuRS (identified as α' and β') were amplified and recombined using suitable plasmids. These recombinant plasmids were transformed or cotransformed into E. coli to produce five monomeric and five heterodimeric LeuRS mutants. Seven of these were successfully overexpressed in vivo and purified, while three dimeric mutants with the β' part of E. coli LeuRS were not successfully expressed. The seven purified mutants catalyzed amino acid activation, although several exhibited reduced aminoacylation properties. Removal of the last 36 residues of the ct subunit of the A. aeolicus enzyme was determined to be deleterious for tRNA charging. Indeed, subunit exchange showed that the cross-species-specific recognition of A. aeolicus tRNA[sup Leu] occurs at the α subunit. None of the mixed E. coli-A, aeolicus enzymes were as thermostable as the native αβ-LeuRS. However, the fusion of the two ct and β peptides from A. aeolicus as a single chain analogous to canonical LeuRS resulted in a product more resistant to heat denaturation than the original enzyme. [ABSTRACT FROM AUTHOR]

Chemokine (C-C motif) ligand 25 (CCL25) and C-X-C motif chemokine 10 (CXCL10) induce the ligand-specific activation of integrin α4β7 to mediate the selective adhesion of lymphocytes to mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1) or vascular cell adhesion molecule-1 (VCAM-1). However, the mechanism underlying the selective binding of different ligands by α4β7 remains obscure. In this study, we demonstrate that CCL25 and CXCL10 induce distinct active conformers of α4β7 with a high affinity for either MAdCAM-1 or VCAM-1. Single-cell force measurements show that CCL25 increases the affinity of α4β7 for MAdCAM-1 but decreases its affinity for VCAM-1, whereas CXCL10 has the opposite effect. Structurally, CCL25 induces a more extended active conformation of α4β7 compared with CXCL10-activated integrin. These two distinct intermediate open α4β7 conformers selectively bind to MAdCAM-1 or VCAM-1 by distinguishing their immunoglobulin domain 2. Notably, Mn2+ fully opens α4β7 with a high affinity for both ligands. Thus, integrin α4β7 adopts different active conformations to switch its ligand-binding specificity. [ABSTRACT FROM AUTHOR]

The controllable synthesis of metal oxide nanoparticles is of fundamental and technological interest. In this article, highly transparent aqueous nanodispersion of ZrO2 with controllable crystalline phase, high concentration, and long-term stability was facilely prepared without any modification via the reaction of inexpensive inorganic zirconium salt and sodium hydroxide in water under an acid surrounding, combined with hydrothermal treatment. The as-prepared transparent nanodispersion had an average particle size of 7 nm, a high stability of 18 months, and a high solid content of 35 wt %. ZrO2 nanocrystals could be readily dispersed in many solvents with high polarity including ethanol, dimethyl sulfoxide, acetic acid, ethylene glycol, and N,N-dimethylformamide, forming stable transparent nanodispersions. Furthermore, highly transparent polyvinyl alcohol/ZrO2 nanocomposite films with high refractive index were successfully prepared with a simple solution mixing route. The refractive index could be tuned from 1.528 to 1.754 (@ 589 nm) by changing the mass fraction (0-80 wt %) of ZrO2 in transparent nanocomposite films. [ABSTRACT FROM AUTHOR]

A spinning disk reactor (SDR) is one of the important process intensification devices. Previous studies primarily focused on the dependence of the liquid flow in a SDR on the operational conditions and liquid properties. However, the effect of hydrophobicity of the disk's surface on the liquid flow in a SDR is rarely reported. In this work, the disk with a hydrophobic surface was prepared, and the effects of surface hydrophobicity, liquid flow rate, rotational speed, and liquid viscosity on the liquid flow patterns as well as the average diameter of a liquid droplet (davg) were investigated by a visualization method. An empirical correlation of davg was suggested, and the deviations were within ±15% when the calculated values of davg were compared with the experimental data. [ABSTRACT FROM AUTHOR]

In this work, the gas-side mass transfer was investigated in a rotating packed bed (RPB) with structured nickel foam packings, with different surface properties, either a nonmodified nickel foam packing (NNP) or a hydrophobic surface-modified nickel foam packing (SNP). Effects on gas-side volumetric mass-transfer coefficient (kGae) of rotational speed, liquid flow rate, and gas flow rate were experimentally studied in the RPB with NNP and SNP. It can be found that the RPB loaded with SNP has a higher mass-transfer efficiency, compared with that loaded with NNP. Based on the experimental data, correlation of kGae in a RPB with structured nickel foam packing was proposed, which can hence provide a fast calculation of mass-transfer coefficients for the RPB design with structured nickel foam packing. [ABSTRACT FROM AUTHOR]

A novel route was proposed for the synthesis of transparent dispersions of monodispersed zinc oxide (ZnO) nanoparticles via a high-gravity reactive precipitation combined with "inorganic-organic successive layer coating" method. The as-prepared nanodispersion had a uniform particle size of about 4 nm, high stability of over 12 months, and still remained transparent at ultrahigh solid content of 60 wt %. Highly transparent polylactide (PLA)/ZnO and PLA/ZnO/cesium doped tungsten oxide CsxWO3 nanocomposite films were further fabricated by a simple solution mixing method. Because of the uniform dispersion of nanoparticles, PLA/ZnO films could maintain the same visible transmittance as pure PLA film even when ZnO content reached 60 parts per hundred of PLA resin by weight (phr). Furthermore, the films could shield almost 100% ultraviolet radiation at ZnO content of up to 5 phr, thereby realizing good antiaging property. Besides their excellent transparency and UV-shielding property, PLA/ZnO/CsxWO3 films could also block 90% near-infrared radiation, thereby displaying excellent heat insulation ability. It could be envisioned that this nanocomposite would have great potential in many applications such as smart windows, agricultural film, fabrics, etc. [ABSTRACT FROM AUTHOR]

This work presents a novel process of nano-Ni preparation by liquid reduction method without surfactant in a combined reactor of a rotating packed bed (RPB) and a stirred tank reactor (STR). The reaction mechanism of this process was studied and the effects of different operating conditions including rotation speed, NaBH4 concentration, liquid volumetric flow rate and liquid circulation time on the characteristics of the nano-Ni were systematically investigated in the RPB to control the morphology and average particle size of the prepared nano-Ni. The average particle size of the prepared nano-Ni can be adjusted from 42 to 130 nm by changing operating conditions and the prepared nano-Ni with a face centered cubic (FCC) structure, an average particle size of 42 nm and a particle size distribution of 30-60 nm was obtained under the optimal operating conditions. This research provides a novel pathway and theoretical basis for controllable preparation production of nano-Ni. [ABSTRACT FROM AUTHOR]

High efficiency and compact design of the desulfurization technology is necessary to meet the strict emission requirement of the marine environment. A rotating packed bed (RPB), having high mass transfer efficiency and small size, is an excellent choice for SO2 removal from the exhaust gas in ships. In this work, SO2 removal in a laboratory and a pilot RPB with sodium sulfite solution were investigated. Experimental results show that the SO2 concentration at the gas outlet of the RPB can decrease sharply and it has no obvious scale up effect. A correlation of the mass transfer coefficient (Kya) was proposed and the predicted Kya agrees with the experimental data with a deviation within ±15%. Compared with the spray tower, the RPB has a higher SO2 removal efficiency and a quarter volume, which displays a bright future for the offshore application of SO2 removal. [ABSTRACT FROM AUTHOR]

A novel multiliquid-inlet rotating packed bed (MLI-RPB), compared to the conventional RPB, was demonstrated to result in higher gas-liquid mass-transfer in our previous studies (Chu et al., Ind. Eng. Chem. Res. 2014, 53, 18580-18584). A comprehensive understanding of the fluid flow inside the MLI-RPB is significant for the internal optimization. In this work, the gas flow in a MLI-RPB was investigated by three-dimensional computational fluid dynamics simulation. The simulated gas pressure drop was validated by the experimental data, within a deviation of ± 15%. Simulation results reveal that the MLI-RPB has special features in the hollow annular zones among packing rings. Five types of internal combinations were designed to improve the turbulence of the gas flow in the hollow annular zones. The tangential slip velocity, turbulent kinetic energy, and ratio of turbulent kinetic energy to overall gas pressure drop of the MLI-RPB with these internal combinations were 1-2, 1-4, and 1-4 times those of the original MLI-RPB, respectively. [ABSTRACT FROM AUTHOR]

Nucleation is the initial step of the crystallization process and is the significant step to prepare nanometer-sized crystalline materials. In this work, we systematically investigated the nucleation kinetics of poorly water-soluble drug sorafenib when precipitated by liquid antisolvent precipitation in high-gravity rotating packed bed. We found that high-gravity field tremendously promoted the nucleation rate, and the nucleation rate was increased by 2-3 orders of magnitude over that in the stirred tank reactor. Moreover, polymer excipients have a significant impact on nucleation; especially, poly(vinylpyrrolidone) (PVP) could increase the nucleation rate by 3 orders of magnitude over that without excipient. Finally, stable amorphous sorafenib nanoparticulate formulation with a particle size of 80 nm was obtained by controlling nucleation in RPB. Compared to the coarse drug, the nanoparticulate formulation performed faster drug release and had much better cytotoxicity. In vivo pharmacokinetics of the nanoparticulate formulation displayed the increase in plasma concentration time curve (AUC0-∞) and maximum plasma concentration (Cmax), which demonstrated nanoparticulate formulation could enhance the bioavailability and exhibit extensive potential in the pharmaceutical industry. [ABSTRACT FROM AUTHOR]

The development of green synthetic approaches is one of the key materials challenges in moving toward semiconductor quantum dots (QDs) for large-scale production and commercial applications. This article presents a comprehensive overview on the synthesis of colloidal QDs prepared via chemical approaches in solution phase, with emphasis on green routes which possess the advantages of environment-friendly raw materials, simple operation process, and robust mass-scale production. The approaches for the synthesis of QDs in batch reactors are summarized, including hot-injection organometallic synthesis, noninjection organometallic synthesis, aqueous synthesis and biosynthesis approaches, with some of the concerns on their limitations for scale-up, followed by some continuous synthetic methods aiming for reproducible and large-scale production. Current advances in continuous synthesis of QDs by microfluidic devices, high-gravity reactors, and spray-based techniques are briefly introduced. We also provide some insights into challenges and opportunities based on our own understanding of this field. [ABSTRACT FROM AUTHOR]

The rotating packed bed (RPB) has drawn wide attention owing to its outstanding advantage in process intensification. In the present study, gas flow characteristics in RPB were investigated by particle image velocimetry (PIV) measurement. The velocity and turbulent kinetic energy (TKE) in the packing zone were obtained and the effects of various parameters were analyzed. During rotation, gas rapidly acquired tangential velocity, which was dominant in resultant velocity. Mean gas velocity increased with the increase of rotational speed, but was almost independent of gas flow rate and packing size at lower rotational speed. Moreover, mean radial and tangential slip velocities were overall positively affected by gas flow rate and rotational speed, respectively. Higher TKE near the inner packing than those in the bulk zone revealed the existence of a gas end-effect zone in RPB. The results could provide a theoretical basis for further study on gas-solid catalytic reaction or the gas-liquid mass transfer process in RPB. [ABSTRACT FROM AUTHOR]

As one of the important bone regeneration materials, α-calcium sulfate hemihydrate (α-CSH) has attracted widespread attention. In this study, a facile method was developed to prepare α-CSH with low aspect ratio via high-gravity continuously reactive precipitation of a calcium sulfate dihydrate (CSD) precursor, using ethanol as a morphology modifier in a rotating packed bed (RPB) reactor, combined with CaCl2 salt solution method under atmospheric pressure with the addition of citric acid with a low concentration (0.06 wt %). The precipitation time of CSD powders in the RPB was dramatically shortened from 30 min to 1 s, and the precursor exhibited more regular short rod shapes and much smaller size, compared to that obtained in a conventional stirring tank reactor (STR). Furthermore, calcium sulfate bone materials with high stability and good mechanical property were prepared by mixing α-CSH and normal saline with a liquid–solid ratio of 0.6. The RPB products had a higher compressive strength (2–3 times) than the STR counterpart. [ABSTRACT FROM AUTHOR]

The development of metal-free catalysts for hydrogenation reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) has been of great increasing scientific and industrial importance. Herein, we reported the preparation of sulfurized graphene (SG) nanomaterials by a well-developed ball-milling method. The as-prepared SG nanomaterials were systematically characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared, and X-ray photoelectron spectroscopy. The SG exhibited flake-like morphology with average size of 100 nm, and the S doping (3.4 atom %) into the nanocarbon molecules results in asymmetry of electron density distribution, providing high catalytic performance for catalytic reduction of 4-NP to 4-AP by using NaBH4 as the reducer. The related catalytic mechanism and reaction path of the reduction were investigated. The effects of different initial 4-NP concentrations, initial reductant concentrations, catalyst dosages, and reaction temperatures were presented, which have not been reported so far. The thermodynamic parameters including activation enthalpy and entropy were determined. [ABSTRACT FROM AUTHOR]

Daidzein (DZ) has a broad spectrum of biological activities, including antioxidant, anti-inflammatory and anticancer as well as cardio- and hepatoprotective properties. The present study was designed to elucidate the in-depth mechanism underlying the neuroprotective efficacy of DZ against spinal cord ischemic/reperfusion injury (SCII) in a rat model by comparison with the standard neuroprotective agent methylprednisolone (MP). A total of 48 rats were divided into four groups of twelve rats in each (n=12). In sham-operated group (Control) group, rats received only saline (Fogarty catheter was inserted without balloon inflation), whereas rats in the SCII induction group (SCII) were subjected to SCII insult by insertion of a Fogarty balloon catheter, which was inflated in the descending thoracic aorta to cause an occlusion. A proportion of rats was treated with DZ (20 mg/kg; DZ+SCII group) or MP (50 mg/kg; MP+SCII group) for seven days prior to and after SCII. The locomotor function (neurological activity) and antioxidant levels (superoxide dismutase and catalase) levels were significantly improved upon treatment with DZ and MP in comparison with those in the SCII group. A concomitant decline in edema, inflammatory markers (myeloperoxidase, tumor necrosis factor-a and nuclear factor κB p65), the apoptotic marker caspase-3 and the number of cells with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling was also observed in the DZ and MP groups. The protein levels of phosphoinositide-3 kinase (PI3K), the phosphorylated Akt/Akt ratio and B-cell lymphoma 2 (Bcl-2) were substantially downregulated, while Bcl-2-associated X protein levels were upregulated SCII insult group, which was inhibited by treatment with DZ. To conclude, pre-treatment with DZ significantly improved the neurological function by upregulating PI3K/Akt signaling and thereby considerably attenuating the inflammatory response and apoptosis, thus maintaining the neuronal count in an SCII-induced rat model. [ABSTRACT FROM AUTHOR]

Optically transparent upconversion luminescent organic-inorganic nanocomposites are of great significance in many fields. The related key science problems are how to control size and uniformity of upconversion nanophosphors, as well as the dispersity of the upconversion nanophosphors in transparent polymer matrix. In this article, we reported a novel route to prepare Gd2O3:Yb3+/Er3+ nanophosphors by high gravity reactive precipitation along with post hydrothermal and calcination process. A rotating packed bed (RPB) reactor was used to create a high-gravity environment for intensified mixing during the precipitation process of particles. The as-prepared Gd2O3:Yb3+/Er3+ nanoparticles exhibited uniform particle size of <100 nm, which is much smaller than the common route (~350 nm). After surface modification, they were also homogeneously mixed with commercial polyurethane (PU), forming flexible transparent composites. The transparent film of Gd2O3:Yb3+/Er3+-PU showed bright visible luminescence under near-infrared light irradiation, promising for upgrades of photovoltaic, photocatalysis, and wearable optoelectronics. [ABSTRACT FROM AUTHOR]

Rotating packed bed (RPB) reactors, with strong centrifugal acceleration up to several hundred times gravitational acceleration, can greatly intensify the gas-liquid mass transfer efficiency. With the improvement of high performance computer clusters and simulation models, a more precise and comprehensive simulation on the gas-liquid flows in RPBs has been achieved by a three-dimensional model. The volume of fluid (VOF) multiphase model, sliding model (SM), and different turbulence models were used to compute the velocity fields and capture the evolution of the gas-liquid interface in the RPB reactor. The liquid flow behavior, droplet size, liquid phase distribution, specific surface area, and mean residence time (MRT) of the liquid phase within the RPB were studied. Compared with two-dimensional simulations, the three-dimensional simulation model can not only describe the liquid breakage and coalescence processes within RPB reactors more clearly, but also obtain results in more satisfactory agreement with experimental data. [ABSTRACT FROM AUTHOR]

As the main inorganic component of human hard tissue, hydroxyapatite (HAp) has attracted extensive interest in biomedical and clinical applications, especially for HAp nanoparticles. In this study, HAp nanorods with a controllable aspect ratio were successfully prepared using NH3•H2O and CO(NH2)2 as aspect ratio modifier by a high-gravity reactive precipitation in a rotating packed bed (RPB) combined with hydrothermal treatment. The influences of the molar ratio of NH3•H2O and CO(NH2)2 and the rotating speed on the average size and aspect ratio of HAp nanorods were systematically explored. The as-synthesized HAp nanorods were investigated with TEM, XRD, and FTIR. The results indicated that the average aspect ratio of HAp nanorods could be facilely controlled in the range 2.2-39. As compared to a traditional batch stirred tank reactor, the RPB reactor had HAp nanorods with a smaller particle width and a wider range of aspect ratio, and a much shorter reaction time from 20 min to 1 s. Further, the potential use of HAp nanorods in the pectin/HAp nanocomposite cements was investigated. The pectin/HAp nanocomposite cement with the highest compressive strength of 29.7 MPa was achieved with the addition of HAp nanorods with the aspect ratio of 15. [ABSTRACT FROM AUTHOR]

The solubility of bicalutamide, megestrol acetate, prednisolone, beclomethasone dipropionate, and clarithromycin in subcritical water (SBCW) at the temperature range from 383.15 to 443.15 K and constant pressure of 5.5 MPa were measured using a modified solvent-antisolvent method combined with SBCW technology. The chemical structures of these five kinds of solutes were stable after processed in SBCW at up to 443.15 K, which was demonstrated by Fourier transformed infrared analysis. The solubility of selected solutes increased exponentially as the temperature of the SBCW increased from 383.15 to 443.15 K. The obtained solubility data were correlated using a modified Apelblat model and the results of the predicted solubility show good agreement with the experimental value. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is attractive for treatment of various cancers, with a high selectivity, minimal long-term effect, and excellent cosmetic appeal. Well water-dispersive photosensitizers with strong optical absorption within the tissue transparency window (700-1000 nm) are needed for efficient PDT. However, clinically used PDT agents based on oligomeric porphyrin units (e.g., protoporphyrin IX) are effective at 532 nm irradiation only. Herein, we synthesized a two-dimensional covalent organic polymer (COP) containing fully conjugated multiple porphyrin macrocycles with sulfonic acid side groups. The resultant COP-P-SO3H is well water-dispersive, showing strong optical absorption within the desired therapeutic window and a high quantum yield of reactive oxygen species, especially singlet oxygen (¹O2), for efficiently killing tumor cells upon near-infrared light irradiation. Our first-principles calculations revealed that the observed high yield ¹O2 resulted from the unique side-on parallel diatomic adsorption (Yeager mode) of triplet oxygen molecules on the highly conjugated porphyrin rings in the photoexcited COP-P-SO3H. [ABSTRACT FROM AUTHOR]

Graphene-based nanocomposites exhibiting excellent properties have been attracting tremendous interest for their extensive applications. In this work, we present an in situ high-gravitational strategy to synthesize silver/graphene oxide (AGO) nanocomposite in an ultrafast manner and propose a possible mechanism for the formation of silver nanoparticles (Ag-NPs) on graphene oxide (GO) sheets with high coverage density. The size of Ag-NPs can be controlled at ∼5 nm with a narrow size distribution. Transparent conductive films are further fabricated with AGO nanocomposite. The visible transmittance of the Ag/reduced graphene oxide (rGO) film with a sheet resistance of 1.12 kΩ/□ can reach 91%. The graphene-based nanocomposites prepared rapidly by the high-gravity technology, which is easy to realize in large-scale production, may provide extensive applications in electronics, catalysis, optics fields, etc. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene (PTFE) material, which is well-known for its excellent anticorrosion properties, was used as wire mesh packing in a rotating packed bed (RPB). The effective interfacial area (ae) and the volumetric liquid-side mass-transfer coefficient (kLae) of the RPB with PTFE packing was studied experimentally by a NaOH-CO2 chemical absorption system and an oxygen-water physical desorption system, respectively. Experimental results showed that both ae and kLae increased with decreasing fiber diameter and pore size. As for material, mass-transfer performance of the PTFE packing was lower than that of the stainless steel wire mesh packing but is applicable in some high-corrosion and -viscosity environments. Moreover, correlations for ae and kLae were proposed. [ABSTRACT FROM AUTHOR]

The effects of solid-state NaOH pretreatment on the efficiency of methane production from semi-dry anaerobic digestion of rose (Rosa rugosa) stalk were investigated at various NaOH loadings (0, 1, 2, and 4% (w/w)). Methane production, process stability and energy balance were analyzed. Results showed that solid-state NaOH pretreatment significantly improved biogas and methane yields of 30-day anaerobic digestion, with increases from 143.7 mL/g volatile solids (VS) added to 157.1 mL/g VS–192.1 mL/g VS added and from 81.8 mL/g VS added to 88.8 mL/g VS–117.7 mL/g VS added, respectively. Solid-state NaOH pretreatment resulted in anaerobic digestion with higher VS reduction and lower technical digestion time. The 4% NaOH-treated group had the highest methane yield of 117.7 mL/g VS added, which was 144% higher compared to the no NaOH-treated group, and the highest net energy recovery. Higher rate of lignocellulose breakage and higher process stability of anaerobic digestion facilitated methane production in the NaOH-pretreated groups. [ABSTRACT FROM AUTHOR]

Micromixing in rotating-packed-bed (RPB) reactors is of great significance for their process-intensifying performance. On the basis of the iodide-iodate reaction system, a two-dimensional computational framework of RPB was developed to investigate the micromixing efficiency in a RPB. The volume-of-fluid multiphase model, laminar finite-rate model, and the Reynolds stress model were adopted to simulate the volumetric fraction of the liquid phase, the concentration distributions, and the effects of rotating speed and liquid flow velocity on the micromixing performance of a RPB. The computational fluid dynamics results showed that the micromixing and reaction processes occurred mainly in the inlet region of RPB packing, which further confirmed the end effect of the packing. An increase of the rotating speed and liquid flow velocity could remarkably enhance the micromixing efficiency in a RPB. On the basis of the incorporation model, the micromixing time in a RPB was estimated as 0.05−0.30 ms, indicating a remarkably quick micromixing performance. [ABSTRACT FROM AUTHOR]

A transparent aqueous nanodispersion of magnesium hydroxide (MH) is first synthesized by using a rotating packed bed (RPB) reactor. Based on this nanodispersion, we further fabricate a transparent poly(vinyl alcohol) (PVA)/MH nanocomposite with enhanced flame-retardant property by a solution-mixing method. The PVA/MH nanocomposite can keep good transparency even at high MH contents. The limiting oxygen index (LOI) of PVA/MH nanocomposite with 50 phr MH is improved by 45% compared to pure PVA. The peak of heat release rate (pHRR) in the microscale combustion calorimetry (MCC) significantly reduces from 453 W/g for pure PVA to 332 W/g. Importantly, a smooth and compact residue layer for the PVA/MH nanocomposite is formed during combustion, which yields a barrier for the transfer of heat and oxygen. These results indicate that the PVA/MH is an excellent transparent flame-retardant material, which opens a door to manufacture transparent and fire-resistant polymer-based nanocomposites with environmental-friendly process. [ABSTRACT FROM AUTHOR]

Toenhance the solubility and dissolution rate, and thus potentiallyimprove the oral bioavailability of cefixime (CFX), amorphous CFXnanoparticles were prepared via high-gravity antisolvent precipitation(HGAP) without the aid of any pharmaceutical additives in a rotatingpacked bed (RPB). The effects of operating variables on particle sizeand distribution were investigated. Compared to raw CFX, the meansize of prepared nanoparticles decreased greatly from about 2.1 μmto 57 nm, and the saturation solubility increased tremendously from0.289 to 0.951 mg/mL. CFX nanoparticles showed good stability andwere capable of generating a maximum supersaturation level, reachingup to ∼22.8 times of raw CFX’s saturation solubility.Further, CFX nanoparticles achieved 100% drug dissolution within 2min, while the raw drug did not dissolve completely after 45 min,suggesting that the solubility and dissolution properties of CFX nanoparticleswere significantly improved. Since the drug recovery ratio achieved99.9%, and the production capacity of lab-scale RPB with a continuousoperation reached 1.8 kg/h, the HGAP method might offer a generaland facile platform for mass production of CFX nanoparticles. [ABSTRACT FROM AUTHOR]

The size of the dispersed phase was a key variable of the liquid-liquid heterogeneous flow system. In this work, the Sauter mean diameter (SMD) of the dispersed phase in a novel helical tube reactor (HTR) was evaluated by using a castor oil-water system. Experimental results showed that the SMD decreased with the increased Reynolds number and volumetric flowrate ratio of water to oil. The SMD in the HTR with vertical charging was smaller ion between calculated and experimental data was within ±20% than that with parallel charging. A dimensionless correlation of SMD in the HTR was proposed and the deviation between calculated and experimental data was within ±20%. [ABSTRACT FROM AUTHOR]

SnO2 nanoparticles were prepared by a continuous hydrothermal process carried out in a helical tube reactor (HTR). The products prepared at different hydrothermal temperatures (from 160 °C to 300 °C) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), selected area electron diffraction (SAED) and UV-Visible spectroscopy (UV-Vis). The obtained SnO2 nanoparticles had a tetragonal structure and mean size of about 4-7 nm. It was found that the mean size of SnO2 nanoparticles increased with the increase of the hydrothermal temperature. The analysis of UV-Visible spectroscopy showed that with an increasing hydrothermal temperature from 160 °C to 300 °C the optical absorption edge shifted from about 320 nm to 350 nm, responding to the optical band gap value variation from 3.78 eV to 3.50 eV and indicating the red-shifted property of the prepared SnO2 nanoparticles. In addition, when employed as a photocatalyst, the as-obtained SnO2 nanoparticles demonstrated good degradation ability for methylene blue solution. [ABSTRACT FROM AUTHOR]

Cefuroxime axetil (CFA) drug nanoparticles were prepared by liquid antisolvent precipitation in a microchannel system with a T-shaped junction formed by a main microchannel and a branch. Isopropyl ether as the antisolvent (high flow rate) was usually passed through the main microchannel, and CFA acetone solution as the solvent (low flow rate) was injected into the branch simultaneously. The solvent diffused from the CFA acetone solution stream into the antisolvent phase, which resulted in the supersaturation of CFA and thus led to the rapid precipitation of CFA nanoparticles. The change of the injection phase from CFA acetone solution to isopropyl ether was found to have a significant effect on the formation of CFA nanoparticles owing to the different contact behavior. The morphology and size of CFA nanoparticles were characterized by scanning electronic microscopy (SEM) and particle size distribution (PSD) measurements by laser diffractometry. Furthermore, the effects of CFA acetone solution velocity, antisolvent velocity, overall velocity, and CFA concentration on the particle size and size distribution were experimentally investigated. The as-prepared CFA nanoparticles were amorphous and exhibited a higher dissolution rate than raw CFA. This work suggests that microfluidics might find wide applications in the development and optimization of drug nanoparticles in the newly emerging field of nanomedicine. [ABSTRACT FROM AUTHOR]

In this Letter, we have fabricated a multifunctional device for highly efficient and inexpensive oil spill cleanup by combining electroless metal deposition with self-assembled monolayers, which has integrated the functions of oil containment booms, oil-sorption materials, oil skimmers, and water–oil separating devices. This functionally integrated device has a lower density than that of water, which leads to a potential application as oil containment booms; it can take up oil that is 3.5 times its own weight, which shows excellent oil-sorption properties, with the water–oil separating yield of the as-prepared device being up to 92%. The device has the advantages of high efficiency, capacity of antiwave, and reproducibility, which is suitable for many types of organic solvents or oils, even for emulsion of petroleum and water, and thus is a proof-of-principle idea to be applied in marine spilt oil cleanup and other water–oil separating systems. [ABSTRACT FROM AUTHOR]

The formation of ordered complex structures is one of the most challenging fields in the research of biomimic materials because those structures are promising with respect to improving the physical and mechanical properties of man-made materials. In this letter, we have developed a novel approach to fabricating complex structures on the mesoscale by combining magnetic-field-induced locomotion and supramolecular-interaction-assisted immobilization. We have employed a magnetic field to locomote the glass fiber, which was modified by the layer-by-layer self-assembly of magnetic nanoparticles, to desired positions and have exploited the supramolecular interaction to immobilize glass fiber onto the appointed position. By magnetically induced micromanipulation, we can drive another fiber across the former one and finally obtain a crossing structure, which can lead to more complex structures on the mesocale. Moreover, we have constructed a mesoscale structure, termed “CHEM”, to demonstrate further the application of this method. [ABSTRACT FROM AUTHOR]

Using ionic liquids for CO2capture is of great interest due to their unique characteristics. However, low gas–liquid mass transfer rates in conventional gas–liquid contactors due to the high viscosities of ionic liquids lead to the significant limitation for large-scale application of CO2capture using ionic liquids. Therefore, there is an urgent demand to develop a novel gas–liquid contactor for the intensification of the mass transfer efficiency in such a system. In this article, CO2absorption with an ionic liquid in a rotating packed bed (RPB) gas–liquid contactor is first reported. It was found that the RPB markedly enhanced the physical absorption of CO2in the ionic liquid in a very short contact time, within seconds. Only one cycle gas–liquid contact in the RPB could make the saturation ratio of CO2in the ionic liquid reach 60%. The effects of various operation conditions on the liquid side volumetric mass transfer coefficient (kLα) were elucidated. Increasing the rotating speed from 1100 to 3100 rpm doubled the kLα. The increase of the liquid flow rate also benefited the enhancement of the kLα. The experimentally measured kLα in the RPB is at least 1 order of magnitude higher than that in a conventional packed tower. A model based on penetration theory was proposed to describe the mechanism of gas–liquid mass transfer in the RPB. The predicted kLα was in good agreement with the experimental data with a deviation of less than 15%. The RPB shows great potential for the industrial application of CO2capture using ionic liquids. [ABSTRACT FROM AUTHOR]

In this work, we have developed a facile and inexpensive method to fabricate a superhydrophobic surface with hierarchical nano- and microstructures. The superhydrophobic surface was prepared through spin coating of a mixture of nano- and microsized calcium carbonate (CaCO3) suspensions on a substrate, followed by modification of a low-surface-energy monolayer of stearic acid. The key parameters of the fabrication of suitable surface morphologies, including the content of CaCO3powder and the percentage of nano- and microsized CaCO3powder, were also investigated. Results showed that the optimum CaCO3content was 40 wt % and the self-cleaning property of the film was achieved only by the addition of 2 wt % microsized CaCO3powder and 38 wt % nanosized CaCO3powder. After modification with a self-assembled monolayer of stearic acid, the as-prepared coating showed self-cleaning properties with a water contact angle as high as 152.8° and a sliding angle of 7.8°. [ABSTRACT FROM AUTHOR]

The organic−inorganic hybrid optical materials with a high transmittance of visible-light have shown great potential applications. However, it is still in challenge to maintain the transparency of optical materials when the inorganic nanoparticles (NPs) are introduced into the polymer matrix because of Rayleigh scattering caused by the severely aggregation of NPs, which is a huge obstacle for its applications. This article reports a transparent “solution” mixing method to fabricate a highly transparent nanocomposite film of zinc oxide (ZnO)/poly (methyl methacrylate)-co-poly (styrene) (PMMA-PS) with the novel UV-shielding properties. The transparent “solution” containing nanoparticles was prepared by phase-transfer of ZnO NPs suspension in hexane to NPs dispersion in toluene with surface modifier. The latter dispersion had the complete transparency as a solution (so-called “solution”). It was found that the incorporation of ZnO NPs not only provided UV-shielding ability to the PMMA-PS nanocomposite film with the same transparency of the pure PMMA-PS film, but also improved the thermal stability of the film. When 2% of the ZnO NPs were added into the PMMA-PS polymer, the nanocomposite film could block UV radiation at 350 nm up to 97% and allow 98% transmittance of visible light at 400 nm. The SEM and TEM studies further confirmed that the ZnO NPs were well distributed in the PMMA-PS polymer matrix with the maximum aggregated nanoparticle size less than 20 nm in diameter. High thermal stability was achieved with a 37 °C increase in the initial decomposition temperature of such nanocomposite compared to the pure PMMA-PS. [ABSTRACT FROM AUTHOR]

We investigate the classical and quantum aspects of non-commutative topological (Chern–Simons) mechanics. We introduce the magnetic field by the minimal substitution in a way which preserves the original symplectic structures. We find that the classical aspect, say, the solutions to the equations of motion, converges to the reduced theory which is obtained by turning off the mass term smoothly. However, the quantum aspect, i.e., the spectra and the angular momenta, does not have such continuous limits. The spectra will become divergent when the mass term is turned off. A scheme is proposed to regularize the spectra so as to get a finite result. In order to verify our regularization scheme, we resort to Dirac theory. We find that there are two constraints during the reduction from the full theory to the reduced one which alter the symplectic structures. The eigenvalues of angular momenta also have no continuous limits, and this situation is similar to the one which has been studied some years ago. The possibility of taking an additional limit is also discussed. [ABSTRACT FROM AUTHOR]