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Delaminations have been detected based on the principle of ultrasonic thickness measurement. However, there are blind zones in the detection of surface delamination. Besides, the high-speed detection system is complicated. A novel permeability perturbation testing (PPT) method for the inspection of delaminations in ferromagnetic materials is proposed in this paper. When DC magnetisation is applied in the thickness direction of steel plate, the delamination in the plate will distort the internal magnetic field, leading to local permeability perturbation. This perturbation is transmitted to the surface layer of steel plate in the thickness direction. Using a differential-type eddy current transducer, internal delaminations are detected by measuring relative variation of surface permeability. The variation of permeability in the near surface of steel plate with the movement of delamination and the change of magnetisation state of the steel plate are obtained through finite element simulation. The feasibility of the above method is further verified through an experiment. This new method has the advantage in high-speed detection of delamination. [ABSTRACT FROM AUTHOR]

A high sensitivity surface plasmon resonance (SPR) based temperature and magnetic field sensor in a dual-core D-shaped photonic crystal fiber (PCF) with two types of holes is reported. The flat surface of the dual-core D-shaped PCF is coated with ethanol as the temperature-sensitive material. A large diameter hole coated with a gold ring is filled with a magnetic fluid as a magnetic field-sensitive material. Using the finite element method (FEM), the electric field distribution mode is simulated, and the loss spectra of the temperature sensing channel (channel I) and magnetic field sensing channel (channel II) are calculated. The influence of the types of metal films and rings, large hole diameter, small hole diameter, and gold film and gold ring thicknesses on the sensor performance are discussed. The results showed that the reported sensor is able to measure temperature and magnetic field independently and simultaneously due to its dual channels. The influence of temperature on magnetic field measurements is reduced by reducing the hole diameter. The results show that the temperature sensitivity is 1.151 nm/°C and the correlation coefficient is 0.9954 from 20 to 70 °C. The magnetic field intensity sensitivity is 0.0779 nm/Oe from 25 to 200 Oe and 0.0212 nm/Oe from 200 to 275 Oe with correlation coefficients of 0.9937 and 0.9989 across these ranges. This high sensitivity D-shaped PCF sensor will promote the development of high-performance dual-parameter devices. [ABSTRACT FROM AUTHOR]

The purpose of this study is to observe the volume change of prostate and laser-ablated lesions in the canine and to explore the mechanism and clinical significance through histopathology. Transperineal laser ablation (TPLA) was performed under the guidance of transrectal ultrasound (TRUS) in eight canines. Two canines were sacrificed 1 day and 1 week after TPLA, respectively. The remaining six canines were sacrificed after finishing transrectal contrast-enhanced ultrasound (TR-CEUS) at three phases. The prostatic volumes immediately following TPLA and 1 week later were larger than before TPLA (20.1 ± 3.9 vs 17.1 ± 3.8 ml; 21.7 ± 3.6 vs 17.1 ± 3.8 ml, p < 0.05), but 1 month later, returned to the preoperative level (17.4 ± 3.2 ml). At three time points, the mean volumes of laser-ablated lesions at 3 W/600 J were 0.6 ± 0.2, 1.1 ± 0.4, and 1.7 ± 0.5 ml, respectively, while those of laser-ablated lesions at 3 W/1200 J were 1.2 ± 0.2, 1.6 ± 0.3, and 2.2 ± 0.5 ml, respectively. The mean volumes of laser-ablated lesions increased significantly over time after TPLA (p < 0.050). The prostate volume transient enlarges after TPLA, which prompts for clinical application that it should prolong appropriately the duration of urinary catheterization to avoid acute urinary retention. Many inflammatory cells were observed in the laser-ablated lesions and adjacent normal prostate parenchyma through histopathology. It is speculated that the inflammatory response is involved in the progression of tissue damage. [ABSTRACT FROM AUTHOR]

The novel random copolymers of L-LA and 2, 2-ethylenedioxy-1, 3-propanediol carbonate (EOPDC) were synthesized in bulk using Sn(Oct)2as a catalyst. The poly(EOPDC -co- L-LA)s obtained were characterized by FT IR,1H NMR,13C NMR, GPC and DSC. The copolymers were obtained with yield of 87.9–95.6%. The number average molecular weight of the copolymer is 1.85–6.18 × 104with a polydispersity of 1.41–1.73. The properties of the copolymer including the enzymatic degradation by proteinase K and drug-controlled release property were also investigated. The results show that the degradation rate of the copolymers increases with increasing LA content in the copolymers. [ABSTRACT FROM PUBLISHER]

Hemicyanine is a group of acentric cation-type dyes, in which one side of the conjugated chain is composed of a quaternary nitrogen-containing heterocycle, and the other side of the conjugated chain is connected to substituted nitrogen through an aryl ring. Different chemical constitutions of hemicyanine and its various connecting modes in polymer lead to abundant topological hemicyanine-based polymers, including linear, star-shaped, brush-shaped, dendritic and hyperbranched macromolecules. These polymers have been used for applications in various roles, such as photographic sensitizers, nonlinear optical materials and biomolecular labeling probes. We will give an overview of the synthesis, structure, properties and applications of series hemicyanine-based polymers. [ABSTRACT FROM AUTHOR]

A convenient and effective ‘ultrasonic dispersion method’ was used to fabricate vector/DNA complexes encapsulated microspheres. Polyamidoamine (PAMAM) dendrimer/DNA complexes protected by a water-soluble polymer, poly- α, β-[ N-(2-hydroxyethyl)-L-aspartamide] (PHEA), were encapsulated in a polymer film mainly composed of cholic acid functionalized star poly(DL-lactide), which degraded through surface erosion mechanism with a fast degradation rate. The PAMAM/DNA complexes encapsulated polymer film was then immersed in ethanol and ultrasonicated to afford the microspheres. The in vitro gene transfections showed PAMAM/DNA complexes protected by PHEA exhibited a much higher transfection activity compared with PAMAM/DNA complexes without the protection by PHEA. The expressions of pGL3-Luc in HEK293 cells could be effectively mediated by the polymer film and microspheres with the presence of PHEA. The ultrasonic dispersion method, which did not involve toxic organic solvents, could keep the bioactivity of DNA and offer good control over the size of microspheres. [ABSTRACT FROM AUTHOR]

Microparticle protein delivery systems based on calcium alginate were fabricated using a very convenient method, i.e. directly shredding the protein-loaded calcium alginate beads into microparticles in a commercial food processor for 3 min. Bovine serum albumin (BSA) as a model protein was encapsulated in the calcium alginate microparticles. The obtained protein-loaded microparticles were then coated with chitosan. This fabrication method offered high encapsulation efficiency and a high particle yield. Compared with beads, the microparticles exhibited a faster release rate in the initial release stage. By comparing the release profiles of uncoated beads/microparticles and chitosan-coated beads/microparticles, it was found that the releases from chitosan-coated beads/microparticles were slower. To examine whether the loaded protein denatured during the microparticle fabrication, trypsin was encapsulated in the calcium alginate microparticles and the bioactivity of trypsin released from the microparticles was measured. [ABSTRACT FROM AUTHOR]

Novel thermo-sensitive magnetomicelles that consist of a magnetic core, Fe3O4-oleic acid (Fe3O4-OA), and an amphiphilic surface layer of thermo-sensitive poly(oleic acid-co-N-isopropylacrylamide) P(OA-co-NIPAAm) co-polymer were prepared. Fe3O4 magnetic cores functionalized with double bonds of oleic acid were prepared by suspension–oxidation reaction. Subsequently, by the co-polymerization of hydrophilic NIPAAm, hydrophobic OA and the Fe3O4-OA magnetic core, the thermo-sensitive amphiphilic polymers (P(OA-co-NIPAAm)) were grafted to obtain Fe3O4-OA-g-P(OA-co-NIPAAm) nanoparticles. The surface polymeric layer of Fe3O4-OA-g-P(OA-co-NIPAAm) nanoparticles would self-assemble in aqueous media to form a micellar structure attributed to the amphiphilic P(OA-co-NIPAAm) polymers. The model drug, prednisone acetate, was loaded in the magnetomicelles and in vitro release behavior of loaded drug in magnetomicelles was further investigated, which showed a thermo-sensitive release behavior due to the thermo-sensitive structural changes of the micellar surface layer. [ABSTRACT FROM AUTHOR]

Water and n-butanol are immiscible. In this paper, i-propanol was found to be surface active for both water and n-butanol using surface tension measurement at 25.0±0.1°C, especially the system with i-propanol in water displays a pronounced decrease in surface tension with a distinct inflexion point indicating aggregation. Investigation on phase behavior of water/i-propanol/n-butanol ternary system at 25.0±0.1°C showed i-propanol could promote remarkably the miscibility of water and n-butanol. Cyclic voltammetric technique was employed to locate the micro-regions in single region, indicating the existence of three micro-regions of water/n-butanol, n-butanol/water and bicontinuous region. Thus, a novel water/i-propanol/n-butanol microemulsion without general surfactant is expected to form. Dynamic light scattering also demonstrated the size (hydrodynamic diameter) distribution of the microemulsion, verifying further the formation of the microemulsion droplets. [ABSTRACT FROM AUTHOR]

A novel pH-sensitive nanogel based on pectin cross-linked with glutaraldehyde (PT-GA) was designed and synthesized for drug delivery. Transmission electron microscope observation shows that the nano-sized gel particles exhibit a spherical morphology. The optical absorbance study of nanogel suspension reveals its pH sensitivity. Cytotoxicity study shows that the nanogel has no apparent inhibitory effect on cells. The in vitro drug-release behavior of the drug-loaded nanogel particles in three kinds of media, i.e., simulated gastric fluid, simulated intestine fluid and simulated colon fluid, was studied. PT-GA nanogel exhibits a faster release at a high pH, and the release could be further accelerated in the presence of pectinolytic enzyme, indicating that the nanogel may be used for colon-specific drug delivery. [ABSTRACT FROM AUTHOR]

Insight into the spatial variation of an ecosystem can provide better understanding of ecological processes and patterns in different scales. Detecting these multiple scales of spatial variation in grassland landscapes is valuable for determining management options, designing proper sampling regimes, and selecting suitable resolutions of remote sensing products. The objective of this study is to examine how environmental factors affect spatial variation of biophysical properties in mixed grassland ecosystems. Field leaf area index (LAI), soil moisture, and topographical parameters (relative elevation, upslope length, and a wetness index) were obtained in three parallel transects of a grassland ecosystem in Saskatchewan, Canada in 2004. One 20-m resolution SPOT 4 (HRVIR) image was acquired at the same period of the growing season but in the following year. Normalized difference vegetation index (NDVI) was calculated from the satellite image of the centre 381-m transect and two extensive 2560-m perpendicular transects. A wavelet approach was used to identify the scales of variations. Statistical results showed that LAI is significantly correlated to the wetness index (r2 = 0.37) and soil moisture (r2 = 0.43). The wetness index is better than relative elevation and upslope length in demonstrating the effect of topography on grassland vegetation. The variation of soil moisture is significant at two small scales of about 20 m and 40 m, and that of the wetness index is at the large scale of 120 m. The variation of grassland LAI is significant at three scales (20 m, 40 m, and 120 m), which indicates that the spatial variation of LAI might be controlled by both topography and soil moisture, though the 120 m is the dominant scale of variation in LAI. NDVI significantly correlated with grassland LAI along the centre transect. The effect of topography on grassland LAI is also proven by the significant relationships between NDVI and the wetness index. The wavelet analysis identifies the variation of two extensive transects at the scale of about 120 m, which is similar to the dominant variation scale of grassland LAI. These results confirmed that the effect of topography on spatial variation can be identified from the appropriate satellite image. This study suggests that the spatial scales of soil and topographic data aid in the selection of appropriate satellite image resolution for monitoring and managing ecosystems. [ABSTRACT FROM AUTHOR]

A series of cholesteryl end-capped biodegradable oligo/poly(trimethylene carbonate)s were synthesized and characterized. The end-capped oligomers/polymers were synthesized by the ring-opening polymerization of trimethylene carbonate (TMC) initiated by cholesterol bearing a hydroxyl group without adding any catalyst. The end-capped oligomers/polymers with different molecular weights were obtained by controlling the feed ratio of the initiator cholesterol to the monomer TMC. The cholesteryl end-capped oligomers/polymers were characterized by Fourier transform-infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR), gel-permeation chromatography (GPC), differential scanning calorimetry (DSC) and polarizing light microscopy (PLM). Incorporation of cholesteryl moieties results in liquid crystallinity of the end-capped oligomers/polymers when their molecular weights are not very high. Using the MTT assay, the end-capped biodegradable oligo/poly(trimethylene carbonate) is proved to have a low cytotoxicity. The microsphere drug-delivery system of an end-capped polymer was fabricated and its drug-release properties were evaluated. [ABSTRACT FROM AUTHOR]

Comparative reactivities of different metal ions in different micellar solutions (cationic, anionic, nonionic micelle) for the hydrolysis of p-nitrophenyl picolinate (PNPP) were investigated spectrophotometrically at pH 7.0 and 25°C. The kinetics analysis was carried out by invoking a model of micellar catalysis. The results show that compared with metal ions in aqueous solution, cationic micelles inhibit metal ion catalyzed hydrolysis of PNPP, anionic micelles accelerate metal ion catalyzed hydrolysis of PNPP and nonionic micelles show no appreciable effect on metal ion catalyzed hydrolysis of PNPP. The higher the electron charge of metal ions, the greater these effects are, indicating electrostatic interactions are the major reason for metal ion catalyzed hydrolysis of PNPP in micellar solution. [ABSTRACT FROM AUTHOR]

This paper describes the effect of four types of amine (ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine) as polar additives on the critical Micellar concentrations (CMCs) of ionic surfactants, [cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)] in buffered solutions (I = 0.1 M KNO3, 0.01 M Tris–TrisH+) at pH 7.00 ± 0.01 by electrical conductivity. It was found that the CMCs of these surfactants all decreased with increasing amine concentrations and the extent of effect followed the sequence: tetraethylenepentamine > triethylenetetramine > diethylenetriamine > ethylenediamine. Based on these results, several empirical linear models were obtained. From the experimental data, it is apparent that the extent of decreasing CMCs of CTAB and SDS by the same amine is roughly similar, and this may be ascribed to the polarity of additives and hydrogen bond interactions. [ABSTRACT FROM AUTHOR]

In this paper, the effects of α, β-cyclodextrins (β-CD) on the critical micelle concentration (CMC) of CTAB, SDS, and Brij35 were investigated at 25°C using electrical conductivity and visible spectrophotometry. The results indicate that α, β-CD increase the CMC of the surfactants by the competitive inclusion of surfactant in cyclodextrin. From the experimental data, an empirical formula for CMC[sup *] (apparent critical micelle concentration) of these three surfactants was obtained. [ABSTRACT FROM AUTHOR]