Absorption of phenol and methylene blue by activated carbon from pecan shells

Activated carbon is produced from pecan shells by chemical activation using phosphoric acid. This activation is followed by the treatment with sodium dodecyl sulfate to prepare the surface for the adsorption of phenol and methylene blue from aqueous solution. The results showed a great ability for methylene blue removal with sorption capacity of 410 mg/g at pH 9 and solution concentration of 35 mg/l, while moderate adsorption was obtained for phenol with a capacity of 18 mg/g at pH 11 and the same solution concentration. The increase or decrease in solution pH has a favorable effect on the sorption of both adsorbates. Langmuir and Freundlich models were used to fit the experimental data. The text was submitted by the authors in English.     

Chitosan based hydrogel microspheres as drug carriers

Chitosan/tripolyphosphate (CHIT/TPP) and chitosan/tripolyphosphate/chondroitin sulfate (CHIT/TPP/CHS) core-shell type microspheres were prepared by polyelectrolyte complexation in order to develop a biocompatible matrix for drug delivery. The continual method using a multi-loop reactor under sterile conditions was applied for microsphere preparation. All the types of microspheres produced were spherical in shape and had a porous structure. The mechanical resistance of the microspheres increased in the presence of CHS as the second polyanion, which toughened the microsphere shell structure. For a drug release application, the process of microsphere preparation was modified by dissolving ofloxacin (OFL), the fluoroquinolone antibiotic, in CHIT solution before complex formation. This study shows the difference in OFL release comparing the microspheres CHIT/TPP and CHIT/TPP/CHS and implies the potential to control this process.     

月桂醇微小球制作及缓释机理的研究

本文用溶剂蒸发法制备了月桂醇缓释微小球。阐述了微球粒径与搅拌速度、温度、核心材料与基质材料比例以及乳化剂浓度、油水相体积比等制备条件的关系。测定了它在乙醇介质与空气中的释放速率;证明了它的释放机制属于整体型扩散渗透体系并用扫描电镜(SEM)观察了微球表现形态。     

Stabilization of dyes against hydrolytic decomposition by the formation of inclusion compounds

The decomposition reactions of the dyes phenol blue and murexide were measured spectroscopically in acidic solution at different temperatures. From these reaction rates and their temperature dependence in the absence and presence of various hosts, the stability constants and the reaction enthalpies of the dye complexes with noncyclic dextrins, cyclodextrins and cucurbituril were calculated.-Cyclodextrin enhances the stability of phenol blue in acidic solution. This effect is even more pronounced with cucurbituril. Due to the molecular structure of murexide this dye cannot form inclusion complexes with hosts containing hydrophobic cavities.     

硅胶微球负载钛硅分子筛TS-1催化剂的制备及对苯氧化合成苯酚的催化性能

将硅胶微球浸渍于钛硅分子筛（TS-1）合成液中,经晶化、焙烧制得负载TS-1分子筛硅胶微球催化剂。 用XRD、IR和SEM测试技术对其进行表征,将其用于过氧化氢氧化苯合成苯酚的反应中。 结果显示,TS-1分子筛能够很好地负载于硅胶表面,晶化温度160 ℃,晶化时间72 h,焙烧温度550 ℃,焙烧时间6 h时,获得的催化剂显示良好的催化性能。 在苯和H2O2初始原料量分别为0.5和0.1 mol、催化剂加入量为8 g、反应温度为60 ℃条件下,经过3 h的反应,苯的转化率达到10.32%,苯酚选择性达到97.12%。 9次重复使用后的苯转化率为9.42%,苯酚选择性为93.14%。     

Integrated approaches for reducing sample size for measurements of trace elemental impurities in plutonium by ICP-OES and ICP-MS

A novel microsphere adsorbent based upon carboxymethyl cellulose sodium/prussian blue composite loaded with Lanthanum(III) (CMC/PB-La) was successfully synthesized via electrostatic ejection device for removal of cesium from contaminated water, and characterized by FT-IR, SEM, EDX and XPS. Influencing factors to adsorption cesium were investigated, including solution pH, adsorbent dosage, contact time, initial concentration, temperature and competing ions. Linear Freundlich isotherm was fitted satisfactorily to the adsorption data, and the adsorption kinetic data was fitted well with pseudo-second-order model. Moreover, the results of γ-irradiation experiments indicate that CMC/PB-La has good radiation stability.     

Effects of lung surfactants on rifampicin release rate from monodisperse rifampicin-loaded PLGA microspheres

We have prepared inhalable and monodisperse poly(lactide-co-glycolide) (PLGA) microspheres targeting tubercle bacilli residing in alveolar macrophages. The effects of pulmonary surfactant on the rifampicin (RFP) release rate from RFP-loaded poly (lactide-co-glycolide) microspheres were studied. Also, those of their surface properties of RFP-loaded PLGA microspheres were studied. The RFP release from RFP/PLGA microspheres was accelerated by adsorption of pulmonary surfactant on the particle surface. The fastest RFP release rate was observed from pulmonary surfactant-adsorbed PLGA particles in pH 7.4 buffer solution compared with those in pH 4.0 buffer solution and saline solution. The slowest release rate was observed in the case when saline solution was used as dispersion phase of RFP/PLGA microspheres, although RFP release rate increased by the addition of pulmonary surfactant. From these results it is suggested that when RFP/PLGA microspheres are administrated by inhalation, the RFP release rates from the particles which are not taken up by alveolar macrophages and remain in the alveoli will be small. On the other hand, the RFP release rates and release amounts will be high after RFP/PLGA microspheres are taken up by alveolar macrophages existing in phagosomes, but they become relatively small after RFP/PLGA microspheres move into phagosome-lysosomes by the fusion of phagosomes with lysosomes. The absolute values of the electrophoretic mobility of PLGA microspheres increased by the adsorption of pulmonary surfactants on the surfaces of PLGA microspheres. By analyzing the experimental data using the soft-particle theory, it was indicated that the microspheres became 'softer' and the surface charge density of microspheres increases by the degradation. On the other hand, the surface of PLGA microspheres became harder and the electric charge density increased by the adsorption of pulmonary surfactant on the surfaces of PLGA microspheres. The changes in the surface charge density with degradation became larger by the adsorption of the lung surfactant on PLGA microsphere surfaces. It is considered that the changes in surface properties of PLGA microspheres affect their uptake efficiency by alveolar macrophage.     

活性碳纤维吸附的研究Ⅰ-不同工艺制备的活性碳纤维的性能比较

本文比较研究了五种不同工艺制备的活性碳纤维（ACF）的产率、比表面积、孔结构、对有机溶剂蒸汽的吸附和脱附性能、对水溶液中亚甲基兰、苯酚和碘的吸附性能以及它们的热稳定性。实验结果表明，水蒸气活化的ACF比化学活化的ACF有更大的比表面积，但前者产品产率较低而后者很高；不论水蒸气活化还是化学活化的ACF，它们对有机溶剂饱和蒸汽的吸附量都较高，脱附和再吸附的性能也都较好，对水溶液中的苯酚都有较好的吸附能力，但化学活化的ACF对亚甲基兰的吸附量显著小于水蒸气活化的ACF，同时磷酸活化的ACF-P对碘的吸附量也明显偏小；除了用KOH活化的ACF外，其它ACF都有很好的热稳定性。     

壳聚糖丝心蛋白包药微球的结构和释放性能研究

近年,高分子微球的研究与开发十分引人注目.将药物包裹于微球中,经主动和被动控制,进入预定靶器官或组织后缓慢释放出,不仅可降低其毒副作用,还可提高其生物活性利用度,壳聚糖(ＣＳ)可作牛血清白蛋白等药物缓释微球的载体[1～3].丝心蛋白(ＦＢ)含18种氨基酸,具有多孔性和良好的渗透性[4],也是一种理想的生物材料.壳聚糖和丝心蛋白共混可交联成半互穿聚合物网络(ＳｅｍｉＩＰＮ)结构.具有智能水凝胶的性能[5].本实验室已用纤维素铜氨液分别与干酪素、海藻酸钠及魔芋共混制得共混膜,两种分子间存在由次价键力引起的很强的相互作用,使其力学性…     

Preparation of uniform-sized pH-sensitive quaternized chitosan microsphere by combining membrane emulsification technique and thermal-gelation method

In this study, uniform-sized pH-sensitive quaternized chitosan microsphere was prepared by combining Shirasu porous glass (SPG) membrane emulsification technique and a novel thermal-gelation method. In this preparation process, the mixture of quaternized chitosan solution and alpha-beta-glycerophosphate (alpha-beta-GP) was used as water phase and dispersed in oil phase to form uniform W/O emulsion by SPG membrane emulsification technique. The droplets solidified into microspheres at 37 degrees C by thermal-gelation method. The whole process was simple and mild. The influence of process conditions on the property of prepared microspheres was investigated and the optimized preparation condition was obtained. As a result, the coefficient of variation (C.V.) of obtained microspheres diameters was below 15%. The obtained microsphere had porous structure and showed apparent pH-sensitivity. It dissolved rapidly in acid solution (pH 5) and kept stable in neutral solution (pH 7.4). The pH-sensitivity of microspheres also affected its drug release behavior. Bovine serum albumin (BSA) as a model drug was encapsulated in microspheres, and it was released rapidly in acid solution and slowly in neutral medium. The novel quaternized chitosan microspheres with pH-sensitivity can be used as drug delivery system in the biomedical field, such as tumor-targeted drug carrier.     

Optical sensor for carbon dioxide combining colorimetric change of a pH indicator and a reference luminescent dye

A new optical CO₂ sensor based on the luminescence intensity change of the europium(III) complex tris(thenoyltrifluoroacetonato) europium(III) dihydrate ([Eu(tta)₃]) caused by the absorption change of various pH indicators—thymol blue, phenol red, or cresol red—with CO₂ was developed and its CO₂ sensing properties were investigated. For all the CO₂ sensors using pH indicators the observed luminescence intensity from [Eu(tta)₃] at 613 nm increased with increasing CO₂ concentration. The linear calibration method based on the plot of (I₁₀₀–I₀)/(I–I₀) versus the inverse of CO₂ concentration was suggested, where I₀ and I₁₀₀ were luminescence intensities at 613 nm of the CO₂ sensor film in 100% nitrogen and 100% gaseous CO₂. In all cases the plots showed good linearity and the correlation factors of the plots, r², were 0.991 for thymol blue, 0.990 for phenol red, and 0.998 for cresol red. The slopes of the plots (A/B) for thymol blue, phenol red, and cresol red were 2.2, 5.2, and 9.0%, respectively. The response times of the CO₂ sensor film were 4.0 s for thymol blue, 4.4 s for phenol red, and 8.8 s for cresol red for switching from nitrogen to CO₂, and the recovery times of films were 36 s for thymol blue, 39.2 s for phenol red, and 56.6 s for cresol red for switching from CO₂ to nitrogen. The signal changes were fully reversible and hysteresis was not observed during the measurements. The highly sensitive CO₂ sensor was developed using thymol blue as an indicator for the CO₂-sensing probe.     

Fabrication of ultrathin polyelectrolyte fibers and their controlled release properties

Ultrathin fibers comprising 2-weak polyelectrolytes, poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH) were fabricated using the electrospinning technique. Methylene blue (MB) was used as a model drug to evaluate the potential application of the fibers for drug delivery. The release of MB was controlled in a nonbuffered medium by changing the pH of the solution. The sustained release of MB in a phosphate buffered saline (PBS) solution was achieved by constructing perfluorosilane networks on the fiber surfaces as capping layers. Temperature controlled release of MB was obtained by depositing temperature sensitive PAA/poly(N-isopropylacrylamide) (PNIPAAM) multilayers onto the fiber surfaces. The controlled release of drugs from electrospun fibers have potential applications as drug carriers in biomedical science.     

具有光导性的磁性高分子微球——反应性铁酞菁与苯乙烯共聚

合成出了带有反应性基团的铁酞菁单体 ,并实现了与苯乙烯单体在磁流体存在下的分散聚合而得磁性高分子微球 .研究了微球结构、组成 ,测定了其磁响应性和光导性     

作为细胞微载体的明胶基缓释微球的制备

用改良的乳化冷凝法制备载牛血清蛋白(BSA)的大粒径明胶微球. 结果表明, 明胶水溶液的质量分数为25%、水相与油相体积比3∶20、搅拌速度300 r/min、交联剂用0.1 mL质量分数为25%的戊二醛、 表面活性剂用0.1 g span-80为制备平均直径约250 μm明胶微球的理想条件. 所制备微球的后处理方法不同, 则明胶微球的表面形貌也不同, 细胞粘附率不同. 空白明胶微球在体外可以完全降解, 载BSA的明胶微球对BSA具有良好的缓释性, 释放时间可长达30 d. 显微镜观察成纤维细胞在明胶微载体上生长良好.     

Effect of bond‐length alternation on the dipole hyperpolarizability of phenol blue

Phenol blue is a merocyanine dye that may exist in resonance between two extreme forms, a neutral keto form and a zwitterionic, charge‐separated eno form. The keto form is stable in the gas phase, while the eno form can be stabilized by solvents. In this work, the bond‐length alternation is used to monitor the change of the dipole hyperpolarizability of phenol blue continuously from the extreme eno to the other extreme keto forms. Intermediate structures were found to give the largest value for the first dipole hyperpolarizability. These values are compatible with the experimental results in different solvents and suggest that phenol blue undergoes structural changes in polar solvents. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/qua.10120     

Hydrogel-shelled biodegradable microspheres for sustained release of encapsulants

Biodegradable microparticles are promising for the sustained release of encapsulated lipophilic drugs. In particular, the microparticles with uniform size show excellent linearity of cumulated release over time with minimized initial burst. Here, we encapsulate the biodegradable microparticles with a hydrogel shell to improve the controllability over the sustained release and suspension stability. With a capillary microfluidic device, monodisperse oil-in-water-in-oil (O/W/O) double-emulsion droplets are produced to have a toluene solution of polylactic acid (PLA) in the core and sodium alginate and calcium-ethylenediaminetetraacetic acid (EDTA) complex in the shell, whereas the continuous oil phase contains acetic acid. As the toluene evaporates, PLA consolidates to form a microsphere in the core. At the same time, acetic acid diffuses from the continuous phase to the water layer, which causes the dissociation of the Ca-EDTA complex and the gelation of alginate. The hydrogel-shelled PLA microspheres are transferred from the oil to an aqueous solution of calcium chloride, which further tightens the gel shell. The resulting core-shell microspheres show sustained release of encapsulants for extended periods as the hydrogel shell serves as a diffusion barrier. Moreover, the hydrogel shells prevent interparticle agglomeration and adhesion to the solid walls, securing high suspension stability during the injection.     

Preparation and Characterization of Vanillin Cross-Linked Chitosan Microspheres of Pterostilbene

A vanillin cross-linked chitosan microsphere delivery system was established for stabilization and controlled release of pterostilbene. The prepared microspheres were characterized by SEM images, FT-IR spectra, thermogravimetry, and X-ray diffraction. FT-IR spectra results indicated that chitosan was cross-linked by vanillin successfully. Thermal analysis showed that pterostilbene had been totally incorporated into the microspheres and the encapsulation of pterostilbene decreases the rate of degradation and increases the stability. XRD analysis was conducted to confirm the results of DSC analysis. The release rate of pterostilbene from microspheres in pH 3.6 buffer solution could be up to 58.1 % within 48 h.     

INVESTIGATION OF POLYDL-LACTIDE-b-POLY（ETHYLENE GLYCOL）-b-POLYDL-LACTIDE MICROSPHERES CONTAINING PLASMID DNA

PolyDL-lactide (PDLLA) and the block copolymer, polyDL-lactide-b-poly(ethylene glycol)-b-polyDL-lactide (PELA) were used as the microsphere matrix to encapsulate plasmid DNA. The PDLLA, PELA, pBR322-1oaded PDLLA and pBR322-1oaded PELA microspheres were prepared by solvent extraction method based on the formation of multiple w1/o/w2 emulsion. The microspheres were characterized by surface morphology, mean particle size, particle size distribution and loading efficiency. The integrity of DNA molecules after being extracted from microspheres was determined by agarose gel electrophoresis. The result suggested that plasmid DNA molecules could retain their integrity after being encapsulated by PELA. The PELA microspheres could prevent plasmid DNA from being digested by DNase. The in vitro degradation and release profiles of plasmid DNA-loaded microspheres were measured in pH - 7.4 buffer solution at 37℃. The in vitro degradation profiles of the microspheres were evaluated by the deterioration in microspheres surface morphology, the molecular weight reduction of polymer, the mass loss of microspheres, the changes of pH values of degradation medium, and the changes of particle size. The in vitro release profiles of the microspheres were assessed by measurement of the amount of DNA presented in the release medium at determined intervals. The release profiles were correlation with the degradation profiles. The release of plasmid DNA from PELA microspheres showed a similar biphasic trend, that is, an initial burst release was followed by a slow, but sustained release.     

Synthesis of bimodal porous structured TiO2 microsphere with high photocatalytic activity for water treatment

In this work bimodal structured titanium dioxide (TiO₂) microsphere has been prepared from commercial TiO₂ powder and nano-sized titania gel via sol–gel spray-coating technique. Crystallization and transformation behavior of titania gel were investigated. The results revealed that the crystallization and transformation of anatase particles were substantially affected by the concentration of solvent and calcination temperature. Anatase crystallite size of 10 nm was obtained at mole ratio of solvent/precursor 50/1 and calcination temperature of 450 °C. The prepared nano-sized titania gel was embedded within the core (commercial TiO₂, P25) during the spraying process. The prepared TiO₂ microsphere was characterized using X-ray diffractometer (XRD), scanning electron microscope (SEM), field emission electron microscope (FESEM) and micropore analysis. The photocatalytic activity was monitored by following the degradation of phenol with activity benchmarked against commercial P25 (Degussa). The increase of photocatalytic activity of TiO₂ microsphere was attributed to the nano-sized anatase crystallite which has been incorporated into the TiO₂ microsphere.     

海藻酸钠的疏水改性及释药性能研究

为了提高对疏水性药物的负载量和缓释作用,将海藻酸钠氧化后与十二胺反应使其进行疏水改性.对改性后聚合物结构进行了表征.研究了聚合物在水溶液及盐溶液中的粘度变化;将聚合物分散于NaCl/CaCl2的混合溶液中制备成凝胶微球,对药物布洛芬进行了包埋释放实验.结果表明,疏水改性后的海藻酸钠粘度增加,其凝胶微球对布洛芬负载量提高,具有较好的缓释作用.