The specific surfaces of peat and wood

The specific surface areas of various particle size ranges of wood and peat were determined. The methods employed are mercury porosimetry, nitrogen adsorption, and solution isotherms. The results indicate that dye solution isotherms offer an accurate means of surface area measurement, however, the values obtained are dependent on (a) the chemical nature of the solute and adsorbent and (b) the molecular dimensions of the solute. Nitrogen isotherms indicate specific surfaces of (21 × 10³)?(27 × 10³) m² kg^?1 for wood depending on the particle size, while an area of 26.5 × 10³ m² kg^?1 was obtained for peat independent of particle size. Acid dye isotherms yield specific surfaces considerably lower than nitrogen isotherm values; for wood (7.3 × 10³)?(9.6 × 10³) m² kg^?1 and for peat, (5.2 × 10³)?(11.8 × 10³) m² kg^?1. Basic dye studies, using wood, indicate surface areas similar in magnitude to those obtained from nitrogen isotherms. For peat, however, very large apparent surface areas are obtained (～100 × 10³ m² kg^?1) and are attributed to chemical interaction between dye molecules and adsorbent and stacking of dye molecules.     

Molecular recognition of the Lewis Y antigen by monoclonal antibodies

The murine monoclonal antibody BR55-2 is directed against thetumor-associated antigen Lewis Y oligosaccharide. The LewisY core antigen is a difucosylated structure consisting of fourhexose units. Analysis of binding profiles of lactoseries isomericstructures by BR55–2 suggest that the binding epitopeincludes the OH-4 and OH-3 groups of the ß-D-galactoseunit, the 6-CH₃ groups of the two fucose units and the N-acetylgroup of the subterminal ß-D-N-acetylglucosamine (ßDGlcNAc).To elucidate the molecular recognition properties of BR55–2for the Y antigen, BR55–2 was cloned, sequenced and itsthree-dimensional structure was examined by molecular modeling.The crystal structure of BR96, another anti-Lewis Y antibody,solved in complex with a nonoate methyl ester Lewis Y tetrasaccharide,and the lectin IV protein in complex with a Lewis b tetrasaccharidecore were used as a guide to probe the molecular basis for BR55–2antigen recognition and specificity. Our modeling study showsthat BR55–2 shares similar recognition features for thedifucosylated type 2 lactoseries Lewis Y structure observedin the BR96-sugar complex. We observe that a major source ofspecificity for the Lewis Y structure by anti-Y antibodies emanatesfrom interaction with the ß-D-N-acetylglucosamineresidue and the nature of the structures extended at the reducingsite of the fucosylated lactosoamine.     

Enhancement of plant and bacterial lectin binding affinities by three-dimensional organized cluster glycosides constructed on helical poly(phenylacetylene) backbones

A series of poly(phenylacetylene)s bearing diverse saccharide pendants--N-acetyl-D-glucosamine, D-lactose, and N-acetyl-D-neuraminic acid--were synthesized by rhodium-mediated polymerizations of the corresponding acetyl-protected glycosylated phenylacetylenes followed by deprotection. The circular dichroism spectra of these glycosylated poly(phenylacetylene)s each displayed split-type Cotton effects in the long absorption region of the conjugated polymer backbone (260-500 nm), thus indicating predominantly one-handed helical conformations in their backbones. The binding affinities of these glycosylated poly(phenylacetylene)s, and those of previously reported phenylacetylenes bearing D-galactose, towards plant and bacterial lectins were investigated by hemagglutination inhibition assay and isothermal titration calorimetry (ITC). The stoichiometries of binding vary strongly, depending on the lectin binding sites and the accessibilities of the carbohydrate residues in the helices. The measured affinities also vary, with the maximum value observed for the interaction between poly-PA-α-Gal and lectin I from Pseudomonas aeruginosa, with a K(d) value of 4 μM per monosaccharide representing a 200-fold increase relative to the corresponding monomer.     

Synthesis of polymer particles with specific lysozyme recognition sites by a molecular imprinting technique

To prepare silica beads covered with a lysozyme‐imprinted polymer layer, we polymerized acrylamide and acrylic acid or acrylamide and N,N‐dimethylaminopropylacrylamide with (NH₄)₂S₂O₈ in a phosphate buffer containing the lysozyme, surface‐modified silica beads, and crosslinkers; the result was the formation of a polymer layer with a lysozyme recognition site on the silica‐bead surface. By quantitative analysis of the supernatant of the solution containing the silica beads, we confirmed that modified silica beads, in contrast to unmodified silica beads, can selectively adsorb lysozymes. The process of binding and releasing the lysozyme to and from the modified silica beads can be repeated several times without degradation of the rebinding ability. A quartz‐crystal microbalance sensor fabricated with a molecularly imprinted polymer layer with a lysozyme recognition site was prepared. When a lysozyme aqueous solution was added to the solution in which the sensor was immersed, a high level of sensitivity and response was observed. High selectivity was also demonstrated by tests with other protein solutions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3378–3387, 2001     

Molecularly imprinted polymers with specific recognition for macromolecules and proteins

The hierarchical system of recognition in nature is based on interaction between the smallest elements in a matrix such as molecules and the cumulative interactions of larger parts such as the helices and sheets of proteins. The active sites of enzymes are composed of several amino acids, which bind the ligand molecules in a very specific way. However, the activity of the site is dependent on the stabilization of the three-dimensional structure by the interactions of hundreds of other residues. Likewise, a biomimetic polymeric network can be prepared by designing interactions between the building blocks of a biocompatible network and the desired specific analyte and stabilizing these interactions by a three-dimensional structure. This structure is at the same time flexible enough to allow for diffusion of solvent and analytes into and out of the network. This paper reviews advances in molecular recognition systems, and outlines methods of making molecularly imprinted polymer systems that can recognize large molecular weight analytes.     

非离子模板剂制备有序介孔氧化铝及表征

以硝酸铝为原料,采用非离子型表面活性剂聚乙二醇为模板剂,磷酸氢二铵为辅助剂,通过沉淀方法合成有序介孔氧化铝。探讨了模板剂的选取、反应终点pH值、反应温度、后处理工艺和辅助剂等条件对合成的有序介孔氧化铝结构影响,采用BET、XRD、TEM等测试技术对样品进行了结构表征,研究结果表明合成的有序介孔氧化铝比表面积大且孔分布窄,形成的蠕虫状孔道具有一定的有序性。     

Characterization of olive oil classes using a Chemsensor and pattern recognition techniques

Classification is an important component of food quality assurance, as methods to guarantee authenticity of food products are widely demanded by food producers, processors, consumers, and regulatory bodies. The objective of this work was to develop a rapid classification method in order to discriminate virgin olive oil, olive oil, and „orujo” olive oil, the prices of which differ dramatically in the market on a ccount of the high quality level of the former. For these purposes, new ChemSensor equipment that combines a headspace autosampler with a mass-selective detector and Pirouette data evaluation software was used. To take into account the large number of samples analyzed (50 samples repeated 10 times), as well as the wide interval of m/z ratios scanned (41–170), chemometric approaches were necessary. Cluster analysis, principal component analysis, K-nearest neighbors, and soft independent modeling of class analogy (SIMCA) were applied to model the different oil classes. The results indicated good classification and prediction abilities, with SIMCA affording the best results (viz. 97% specificity).     

An algorithm for three-dimensional Monte-Carlo simulation of charge distribution at biofunctionalized surfaces

In this work, a Monte-Carlo algorithm in the constant-voltage ensemble for the calculation of 3d charge concentrations at charged surfaces functionalized with biomolecules is presented. The motivation for this work is the theoretical understanding of biofunctionalized surfaces in nanowire field-effect biosensors (BioFETs). This work provides the simulation capability for the boundary layer that is crucial in the detection mechanism of these sensors; slight changes in the charge concentration in the boundary layer upon binding of analyte molecules modulate the conductance of nanowire transducers. The simulation of biofunctionalized surfaces poses special requirements on the Monte-Carlo simulations and these are addressed by the algorithm. The constant-voltage ensemble enables us to include the right boundary conditions; the dna strands can be rotated with respect to the surface; and several molecules can be placed in a single simulation box to achieve good statistics in the case of low ionic concentrations relevant in experiments. Simulation results are presented for the leading example of surfaces functionalized with pna and with single- and double-stranded dna in a sodium-chloride electrolyte. These quantitative results make it possible to quantify the screening of the biomolecule charge due to the counter-ions around the biomolecules and the electrical double layer. The resulting concentration profiles show a three-layer structure and non-trivial interactions between the electric double layer and the counter-ions. The numerical results are also important as a reference for the development of simpler screening models.     

Click synthesis of glycosylated porphyrin-cored PAMAM dendrimers with specific recognition and thermosensitivity

Glycoporphyrin dendrimers have received increasing attentions due to their distinct physical and chemistry properties, such as fluorescence and water solubility. They also acted as a promising photodynamic therapy (PDT) sensitizer and used in the study of carbohydrate-protein interaction. In this study, different generations of porphyrin-cored dendrimers consisting of glycosylated siloxane-poly (amido amine) typed dendron (PP-Si-PAMAM-D_m-Lac, m?=?1, 2, and 3), multifunctional specific-targeting sensitizers, had been synthesized via click reaction. The structure of PP-Si-PAMAM-D_m-Lac was characterized by ¹H NMR, GPC, FT-IR, UV-vis and fluorescence analyses. This glycoporphyrin dendrimers, not only obtained high fluorescence quantum yield and singlet oxygen production efficiency, but also showed specific recognition of lectin and remarkable temperature-responsive property (20–80 °C). These properties proved a facile click synthetic strategy of glycosylated siloxane-poly (amido amine) typed dendrimers with multiple functions as a promising tumor-selective photsensitizer (PS) for PDT and also allow applications in highly sensitive fluorescent probes over a larger temperature window.     

The role of surface inhomogeneities in pattern formation on catalytic surfaces

A microscopic modelling approach is used to analyze the occurrence of spatial concentration and temperature patterns on catalytic surfaces, e.g. catalytic wires, gauzes, and foils. These patterns come about through the coupling of different local states on the catalytic surfaces by transport processes including heat transfer by radiation. The role of the microscopic surface structure in the initiation, propagation and stabilization of wave patterns is treated by analytical techniques and further illustrated with numerical examples.     

Synthesis of star polymers by organized polymerization of macromonomers

Vinylbenzyl-terminated polyisoprene (PI) macromonomers were synthesized by the coupling reaction of the corresponding living anions with p-chloromethylstyrene. PI stars were prepared by the free-radical crosslinking of PI macromonomers with divinylbenzene (DVB) in n-heptane. No macrogelation was observed during polymerization. The radical copolymerization of PI macromonomer with DVB led to microgelation in micelles formed by PI macromonomers in the selective solvent (organized polymerization). The arm number of star polymers depended strongly on the concentration ratio of DVB to macromonomer ends.     

超重力技术制备有序介孔氧化铝

从微观混合角度探讨有序介孔氧化铝制备过程,以硝酸铝为铝源,碳酸铵为沉淀剂,PEG 1540为模板剂,采用沉淀法在旋转填充床中制备有序介孔氧化铝。考察了旋转床转速、初始混合方式、反应温度、加料速度等因素对介孔结构的影响。研究结果表明采用超重力技术可以合成比表面积高、孔径分布窄、具有蠕虫状孔道、有序性较好的介孔氧化铝,进一步分析结果表明超重力技术在介孔氧化铝的合成过程中对孔结构有很好的控制作用。     

The preparative refinement of steroid specific antibodies by affinity chromatography combined with electrophoretic desorption. Apparatus and method

The preparative refinement of antibodies to testosterone and 5α-dihydrotestosterone was achieved by prepurification (filtration, fractionation with ammoniumsulphate), followed by affinity chromatography of the antiserum. The affinity sorbent was synthesised by coupling 5α-dihydrotestosterone with Sepharose CL 6B. After elution of the interfering admixture, there was desorption by the use of an electric field, using a specially developed apparatus. This apparatus and the method employed provided preparative amounts of antibodies, without significant impairment of affinity. The interfering self fluorescence of the serum was greatly diminished by this refinement procedure. The refined antibodies obtained were suitable for use with sensitive fluorometric testings (i.e. homogeneous fluoroimmunoassay).     

Fault diagnosis of multivariate systems using pattern recognition and multisensor data analysis technique

A pattern recognition-based methodology is proposed for fault diagnosis of multivariate and dynamic systems. Noisy input patterns, belonging to a class of event(s), are first scaled to unit variance and zero mean. This step, termed as a harmonizing step, reduces magnitude difference amongst patterns belonging to a class of event(s). Existence of low frequency segments, such as ramp-type trends, in a pattern hampers the efficacy of the harmonizing step. In this work, a digital band-pass filter is designed to eliminate the ramp-type segments and decrease noise intensity. Then, the Principal Component Analysis (PCA) technique is applied in order to describe the information space by a set of uncorrelated and fictitious data sources. A wavelet-based methodology is employed for each new sensor to extract pattern features. A binary decision tree is used to classify the extracted features. The outputs of each decision tree are: (1) the a posteriori probabilities that an unlabeled input pattern belongs to different classes of events; and (2) the probability confidence limits that input pattern may be classified to any of known classes. As the last step, any of two consensus theory-based techniques or evidence theory are utilized to combine the outputs of the decision trees and find the best classes of events describing system behavior. The performance of the proposed technique is examined by diagnosis of simulated faulty behavior for the Tennessee Eastman Process.     

非对称两嵌段高分子在选择性壁面识别吸附的Monte Carlo模拟

采用自由空间的Monte Carlo（MC）方法研究了两嵌段非对称高分子在选择性壁面上的吸附与识别。研究表明;非对称嵌段高分子同对称嵌段高分子一样;在选择性壁面的吸附可分为吸附和识别两个过程。对高分子构型研究的结果发现;无论条纹宽度如何变化;高分子在垂直于z方向的均方回转半径总是小于其垂直另两方向的值。在条纹宽度一定的情况下;尾式构型比率随链节B与白色条纹壁面作用能Ψ ^B-white增加先增加然后趋于不变。在Ψ ^B-white不变的情况下;尾式构型比率则随条纹数的增加而增加。环式构型比率在条纹较宽时会随Ψ ^B-white有一小的下降趋势;而在条纹较窄时下降幅度较大。