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Banerjee, Kyle, and Bonnie Parks, Eds. Migrating Library Data: A Practical Manual. Neal-Schuman/American Library Association, June 2017. 272p. $56. Oversize pb. 978-0-8389-1503-5. Table of Contents. Index. Websites. Additional Resources. Index. [...]

4Q * 3P * M * J Decades of the 20th and 21st Centuries. Enslow, 2015. 96p. PLB $34.60. Timeline. Glossary. Index. Illus. Photos. Feinstein, Stephen. The 1950s. 978-0-76606930-5. --. [...]

Art Index TV. 202 min. Dist. by Art Index TV. Kanopystreaming.com. 2016. $69.99. S Gr 11 Up--This series of 30-minute interviews by art administrator and filmmaker Joy Glidden focuses on [...]

* 14: Dred Scott, Wong Kim Ark & Vanessa Lopez. 67 minutes. w/English & Spanish subtitles. Dist. by Graham Street Productions. 14themovie.com. 2014. $125. UPC 857670005114. Gr 8 Up--From the [...]

Embeddings of maximal tori in classical groups over fields of characteristic not 2 are the subject matter of several recent papers. The aim of the present paper is to give necessary and sufficient conditions for such an embedding to exist, when the base field is a local field, or the field of real numbers. This completes the results of [3], where a complete criterion is given for the Hasse principle to hold when the base field is a global field.

Summary. A current challenge in plant biology is to identify the structural and functional components of plasmodesmata (PDs). The use of plant tissue as a source material for plasmodesmal characterisation has had limited success, so we have explored the frequency and features of PDs occurring in suspension cell cultures of Arabidopsis thaliana. This material has the advantages of homogeneity, quantity, and ease of disruption. Using light and electron microscopy and immunostaining for callose and calreticulin, we showed that suspension cells laid down abundant PDs in division walls, and that vestiges of these structures were retained as half PDs even when the cell-to-cell contacts were disrupted during culture growth. Although callose was a reliable marker for PD distribution, which was deposited in an organised collar around the neck of PDs, it was not abundant in unstressed cells. Calreticulin and the chemical stain 3,3'-dihexyloxacarbocyanine iodide also provided useful markers when monitoring PDs in cell wall preparations by light microscopy. Purified cell walls were shown to be virtually free of contamination from cytoplasmic components, except for the presence of small amounts of cortical endoplasmic reticulum attached to PDs. Hence, clean cell walls from A. thaliana suspension cells provide a valuable resource for a proteomic approach to the analysis of plasmodesmal components.

Avidin and its bacterial analogue streptavidin exhibit similarly high affinities toward the vitamin biotin. The extremely high affinity of these two proteins has been utilized as a powerful tool in many biotechnological applications. Although avidin and streptavidin have similar tertiary and quaternary structures, they differ in many of their properties. Here we show that avidin enhances the alkaline hydrolysis of biotinyl p-nitrophenyl ester, whereas streptavidin protects this reaction even under extreme alkaline conditions (pH > 12). Unlike normal enzymatic catalysis, the hydrolysis reaction proceeds as a single cycle with no turnover because of the extremely high affinity of the protein for one of the reaction products (i.e. free biotin). The three-dimensional crystal structures of avidin (2 A) and streptavidin (2.4 A) complexed with the amide analogue, biotinyl p-nitroanilide, as a model for the p-nitrophenyl ester, revealed structural insights into the factors that enhance or protect the hydrolysis reaction. The data demonstrate that several molecular features of avidin are responsible for the enhanced hydrolysis of biotinyl p-nitrophenyl ester. These include the nature of a decisive flexible loop, the presence of an obtrusive arginine 114, and a newly formed critical interaction between lysine 111 and the nitro group of the substrate. The open conformation of the loop serves to expose the substrate to the solvent, and the arginine shifts the p-nitroanilide moiety toward the interacting lysine, which increases the electron withdrawing characteristics and consequent electrophilicity of the carbonyl group of the substrate. Streptavidin lacked such molecular properties, and analogous interactions with the substrate were consequently absent. The information derived from these structures may provide insight into the action of artificial protein catalysts and the evolution of catalytic sites in general.

The fluorescent probe dimethylaminonaphthylsulfonamide is covalently bound to the ends of the pol(ethylene glycol) chains of the swellable block copolymers poly(ethylene glycol)–polystyrene (PEG-PS) and poly(ethylene glycol)–poly(ethylene imine) (PEG-PEI) to investigate the molecular mobility inside the polymers, swollen by different liquids. Steady-state and time-resolved studies of the Stokes shift between absorption and fluorescence spectra reveal that the probe is solvated by both the polymer matrix and the liquid phase. The extent of solvation by the liquid and the mobility of the microenvironment of the probe depend on both the swelling volume of the polymer and the solubility of the probe in this liquid. Steady-state and time-resolved fluorescence depolarisation measurements show that the polymer matrix forms a very rigid solvent cage, which almost completely immobilizes the probe. Upon solvation of the probe by the liquid, the mobility of the probe increases. In PEG-PEI swollen by polar solvents, the mobilities of the probe itself and of its microenvironment, although not reaching the values observed in homogeneous solution, are significantly higher than in PEG-PS, due to the hydrophilic nature of the polymeric backbone in PEG-PEI.

Pentacyclic triterpenes from the 11-keto-boswellic acid series were identified as the active principal ingredients of Boswellia resin, inhibiting the key enzyme of leukotriene biosynthesis, 5-lipoxygenase (5-LO). Of the genuine boswellic acids hitherto characterized, 3-O-acetyl-11-keto-β-boswellic acid, AKBA (1), proved to be the most potent inhibitor of 5-LO. In the course of purification of further boswellic acid derivatives from Boswellia resin, we observed the degradation of the natural compound 3-O-acetyl-11-hydroxy-β-boswellic acid (2) to the thermodynamically more stable product 3-O-acetyl-9,11-dehydro-β-boswellic acid (4). The metastable intermediate of this conversion, under moderate conditions of workup in methanolic solutions, was identified as 3-O-acetyl-11-methoxy-β-boswellic acid (3). The novel artifactual boswellic acid derivatives inhibited 5-LO product formation in intact cells with different characteristics:  4 almost totally abolished 5-LO activity, with an IC50 of 0.75 μM, whereas 3 and 9,11-dehydro-β-boswellic acid (5), the deacetylated analogue of 4, were incomplete inhibitors. The data suggest that the conditions chosen for the workup of Boswellia extracts could significantly influence the potency of their biological actions and their potential therapeutic effectiveness.

Abstract: Cationic polystyrene nanoparticles, as a model drug carrier system for nucleic acids, are capable of binding negatively charged oligonucleotides by multiple electrostatic interactions. The effect of the adsorption of phosphorothioate oligonucleotides on the physicochemical properties of the carrier system was investigated for uncoated and sterically stabilized latex particles. Turbidity measurements and photon-correlation spectroscopy indicate that the colloidal stability of the nanoparticle-oligonucleotide conjugates is influenced by the number of oligonucleotides adsorbed on the carrier. Especially in the case of the uncoated material, a destabilizing effect has been observed up to oligonucleotide concentrations of 2.7 μmol/g polymer. Strikingly, at higher concentrations the latexes exhibit colloidal stability similar to the oligonucleotide-free samples. These results were correlated to zeta-potential measurements demonstrating a reversal from positive to negative values of the zeta potential with increasing oligonucleotide concentration. The points of zero charge of the particles are in the region of maximum coagulation. These findings were compared to adsorption studies and calculations based on the random sequential adsorption model. It appears that at first the colloidal stability of the carrier systems is diminished with increasing oligonucleotide adsorption, while higher surface coverages lead to a significant reduction in coagulation. At the saturation level the surface coverage can be considered as a monolayer of “side-on” adsorbed molecules and the conjugates exhibit colloidal stability similar to the bare particles without adsorbed molecules.

The crystal structure of a family‐III cellulose‐binding domain (CBD) from the cellulosomal scaffoldin subunit of Clostridium thermocellum has been determined at 1.75 A resolution. The protein forms a nine‐stranded beta sandwich with a jelly roll topology and binds a calcium ion. conserved, surface‐exposed residues map into two defined surfaces located on opposite sides of the molecule. One of these faces is dominated by a planar linear strip of aromatic and polar residues which are proposed to interact with crystalline cellulose. The other conserved residues are contained in a shallow groove, the function of which is currently unknown, and which has not been observed previously in other families of CBDs. On the basis of modeling studies combined with comparisons of recently determined NMR structures for other CBDs, a general model for the binding of CBDs to cellulose is presented. Although the proposed binding of the CBD to cellulose is essentially a surface interaction, specific types and combinations of amino acids appear to interact selectively with glucose moieties positioned on three adjacent chains of the cellulose surface. The major interaction is characterized by the planar strip of aromatic residues, which align along one of the chains. In addition, polar amino acid residues are proposed to anchor the CBD molecule to two other adjacent chains of crystalline cellulose.

Egg-white avidin was modified with the tryptophan-specific reagent 2-hydroxy-5-nitrobenzyl bromide. The complete loss of biotin-binding activity was achieved upon modification of an average of one tryptophan residue per avidin subunit. The identity of the modified residues was determined by isolating the relevant tryptic and chymotryptic peptides from CNBr-cleaved avidin fragments. The results demonstrate that Trp-70 and Trp-110 are modified in approximately equivalent proportions. It is believed that these residues are located in the active site of avidin and take part in the binding of biotin.

Egg-white avidin was treated with 1-fluoro-2,4-dinitrobenzene. Modification of an average of one lysine residue per avidin subunit caused the complete loss of biotin binding. Tryptic peptides obtained from the 2,4-dinitrophenylated avidin were fractionated by reversed-phase h.p.l.c. Three peptides contained the 2,4-dinitrophenyl group. Amino acid analysis revealed that lysine residues 45, 94 and 111 are modified and probably comprise part of the biotin-binding site.

Ferrozement ist bekannt als Werkstoff für dünnwandige, in der Regel 10 bis 20 mm dicke Bauteile. Er besteht aus Zementmörtel mit darin eingebetteten Maschendrahtlagen. Der Autor beschreibt die Tragwirkung des Werkstoffs und gibt Bemessungshilfen für die Berechnung von Bauteilen aus Ferrozement. Die Möglichkeiten des Ferrozements werden anhand beeindruckender Bauwerke erläutert.

An Hand einer graphischen Darstellung von H. Kelker werden die vielfältigen Problemstellungen der Analytischen Chemie und die Zusammenhänge mit allen Lebensbereichen gezeigt. Die Ausbildung in Analytischer Chemie ist an den deutschen Hochschulen unterschiedlich geregelt. An einzelnen Hochschulen wird die Möglichkeit eines vertieften Studiums geboten. Dies wird am Beispiel der Universität Tübingen aufgezeigt.

The preparation of GdVO4:Bi3+ ceramics is indicated. Bismuth shows a strong tendency to evaporate during the sintering process. Time-resolved emission spectroscopy shows for sufficiently low Bi3+ concentrations subsequently: blue VO43-emission with a decay time corresponding to the transfer rate (106 s-1), yellow VO43--Bi3+ emission, rare-earth impurity emission and VO43--Bi3+ afterglow.

This work reports the synthesis and characterization of a new polystyrene-based graft copolymer. By immobilization of transition metal complexes it shows high potential for selective heterogeneous hydrogenation under outstanding mild conditions. Here, a branched poly(ethylene imine) with average Mr around 3×104 was used to be grafted on acetylated polystyrene beads. 13C solid state NMR investigations demonstrate a high mobility and flexibility of the chains of this spacer due to branching as compared to, e.g., linear poly(ethylene glycol) with Mr around 3000.

Derivatives of poly(oxyethylene) with chlorine and aldehyde functions have been prepared by chemical modification in an one-step and two-step reaction respectively with thionyl chloride and 4-hydroxy benzaldehyde in excellent yields. The functionality of these important intermediates has been investigated spectroscopically and demonstrated by chemical conversion of the terminal groups.

Summary The synthesis of di-(4-formylphenyloxyethyl) poly(oxyethylene) and the corresponding oxime derivative are described. Kinetic aspects of the reaction of the dichloro telechelic with 4-hydroxy benzaldehyde are investigated and discussed.

The complexation properties of poly(ethyleneimine) were investigated for cobalt, nickel, zinc, cadmium, and copper using membrane filtration. The elution curves of each metal were determined at different pH values in homogeneous phase. Poly(ethyleneimine) was found to be an effective complexing agent and suitable for retention and separation of metals in aqueous diluted solutions.

Twelve poly(oxyethylene) derivatives were characterized by their 13C-NMR spectra and compared in terms of their chemical shifts. Substituent effects of the halogen series, of various ethers, nitrogen terminated compounds and some other derivatives were investigated. 13C-NMR spectroscopy is discussed as control method for functionalization reactions.

Summary: A supercritical carbon dioxide hop extract has been analysed using on-line coupling of high performance liquid chromatography (HPLC) with1H nuclear magnetic resonance (NMR) spectroscopy. For the first time high quality NMR spectra of the six major hop bitter acids were recorded by employing the stopped-flow detection mode. The resolution of the spectra obtained is similar to that of conventionally recorded spectra. All data are in agreement with the known structures.

The thermal immobilization of polysiloxanes bearing carboxyalkyl functional groups has been investigated. Under conditions of reduced carrier-gas flow, in particular with water vapour saturated, carrier-gas, high degrees of immobilization could be achieved at moderate temperatures (<200°C). The mechanism of immobilization is shown two involve condensation of carboxyl groups of the polysiloxane with silanol groups either originally present in the polymer or formed during the immobilization process. Other polysiloxane stationary phases could also be immobilized under similar conditions when mixed with carboxyalkyl polysiloxanes. In particular, cyanoalkyl silicones which are otherwise difficult to crosslink, are amenable to this form of immobilisation.

The preparation of cis- and trans-1,2-bis(2-pyridyl)-ethylene (BPE) is described and the different coordination behavior of the two isomers on the basis of their complexes with nickel(II) and zinc(II) are discussed. Fourteen new complexes have been prepared and characterized utilizing electronic spectra, vibrational spectra (conventional and far-infrared), magnetism, electrolytic conductance, and thermal analysis. Eleven further complexes could be detected by thermal analysis. Whereas zinc complexes of both ligands are tetrahedral, the nickel complexes of trans-BPE are planar and octahedral, those of cis-BPE tetrahedral, square-planar and five-coordinate. In chloroform solution the dissociation equilibrium Ni(cis-BPE)2Cl2 (five-coordinate) ⇋ Ni(cis-BPE)Cl2 (tetrahedral) + cis-BPE was studied spectrophotometrically. By the addition of methanol to cis-BPE complexes under mild conditions, tetragonal 1,2-bis(2-pyridyl)ethyl-methylether complexes are obtained.

Pulsed field gradient NMR has been applied to study mass transfer, flow, and dispersion in packed chromatographic columns. A single measurement allows the determination of the full displacement probability distribution of all fluid particles located in the measurement volume. Depending on the orientation of the pulsed magnetic field gradient with respect to the net flow direction, the so-called averaged propagator is obtained independently and quantitatively for either the axial or the transverse fluid particle displacements, over an experimentally adjustable observation time. Thus, this technique can act on a dynamic time scale ranging from a few to several hundred milliseconds. This enabled us to detect the stagnant mobile phase in packed chromatographic columns and to follow the mass transfer between the stagnant solvent and the stream of mobile phase percolating through the column bed. With field gradients in the direction of net flow velocity, mean fluid particle displacements ranging between 0.07 and 100 times the average diameter of the stationary phase particles could be analyzed in terms of the intimately associated averaged propagator, with observation times between 30 and 960 ms. Starting in the absence of flow, the development from the Gaussian propagator for molecular diffusion in the packing (centered at zero net displacement) toward the fully established Gaussian propagator (parallel to the onset and increase of externally driven flow) is recorded, characterizing convection-driven dispersion in the packing. For short observation times, the mass transfer between the deep pools of stagnant mobile phase in the totally porous support particles and the interstitial space in the packed bed is found to be incomplete and the transition toward complete exchange is followed. The results indicate that the stagnant mobile-phase mass transfer in the classical HPLC silica-based stationary phase is purely diffusion-controlled.

Summary: Chiral recognition of many enantiomeric solutes by a chiral amide stationary phase is based mainly on hydrogen bonding. A chiral-recognition-factor CHI is proposed, given by the difference of the enthalpy change in the enantiomer discrimination, standardized with respect to the specific interaction of the solutes with the diamide core of the stationary phase. The r�le of the entropy part is also discussed. By extrapolation of the retention behaviour to elevated temperature, peak inversion of enantiomers is predicted.

A method for the separation of substituted tetraphenylporphyrins by preparative liquid chromatography is reported. The quality of the columns formed by axial compression of various stationary phases is tested.

Methyl esters of the pentafluoropropionyl-amino acid derivatives of the tetrafunctional, sulphur-bridged, stereoisomeric lanthionines, cystathionines and β-methyl-lanthionines were resolved on glass capillaries coated with the chiral stationary phase N-propionyl-L-valine-N-tert-butylamide-polysiloxane (Chirasil-Val) within 35min. Interestingly, L-cystathionine elutes before its D-enantiomer in contrast to the usual order of emergence on an L-phase. The method was applied to the polypeptide antibiotic nisin, which contains mesolanthionine and 2S,3S,6R-3-methyl-lanthionine.

Summary: We have used capillary gas chromatography/mass spectrometry to characterize extracts of Posidonomia shales and of fossil wood (gagat) found in these shales. Samples were obtained from Dotternhausen oil shale formation (FRG) belonging to LIAS-epsilon (Toarcien).Identified components are n-alkanes (C7 to C27), isoprenoid hydrocarbons (like pristane and phytane) and cycloalkanes with 6 to 9 carbon atoms. Aromatic hydrocarbons were also found in the low boiling fraction of extracts of fossil wood. To obtain more detailed information about genesis and maturity of the Dotternhausen sediments we also applied Cross Polarisation Magic Angle Spin-13C-Nuclear Magnetic Resonance (CP/MAS-13C-NMR) spectroscopy. We compared the solid state spectra of fossil wood out of Posidonomia shales with the solid state13C-NMR-spectra of humic substances of different age and different origin. We found that the solid state spectra of humic substances of increasing age and the solid state spectra of fossil wood show striking similarity. The results are discussed with respect to the maturity of the Dotternhausen sediments and the genesis of fossil fuels where humic substances may act as intermediates.

Porous microbeads of low cross-linked polystyrene (PS) grafted with poly(ethylene glycol) chains (PEG) are labeled at the free chain ends with 3-(1,6-diphenyl-1,3,5-hexatrienyl)propionic acid (DPH-PA) and 1-(dimethylamino)naphthalene-5-sulfonic acid (DANS), which probe the polarizability, polarity, and viscosity of their environments. The beads are investigated in a series of pure liquid phases and in acetonitrile/water mixtures by electronic absorption and steady state as well as time-resolved fluorescence spectroscopy. The extent of solvation in the polymer/liquid interphase is characterized from spectral shifts by introducing a solvation fraction which quantifies the relative amount of polymer and liquid in the solvation shell. The rotational mobility of DPH-PA is derived from time-resolved fluorescence anisotropy measurements. Depending on the liquid phase, the rotational correlation times vary strongly between τR = 500 ps and 100 ns. The shortest τR-values are found in liquids which are able to solvate both the fluorophore and the polymer, e.g. toluene and acetonitrile. Long correlation times are observed in the presence of aliphatic hydrocarbons, which do not solvate the bead and therefore cannot penetrate into the polymeric frame, and in presence of water, which solvates PEG but not PS and DPH. In contrast, water is able to weakly solvate DANS chemically bound to the polymeric frame.

Xylanase activity of Clostridium thermocellum, an anaerobic thermophilic cellulolytic bacterium, was characterized. The activity was localized both in the cellulosome (the principal multienzyme, cellulose-solubilizing protein complex) and in noncellulosomal fractions. Each of these fractions contained at least four major polypeptide bands which contributed to the xylanolytic activity. In both cases, pH and temperature optima, product pattern, and other features of the xylanase activity were almost identical. The main difference was in the average molecular weights of the respective polypeptides which appeared responsible for the activity. In the noncellulosomal fraction, xylanases with Mrs ranging from 30,000 to 65,000 were detected. Distinct from these were the cellulosomal xylanases, which exhibited much larger Mrs (up to 170,000). The cellulosome-associated xylanases corresponded to known cellulosomal subunits, some of which also exhibited endoglucanase activity, and others which coincided with subunits which appeared to express exoglucanaselike activity. In contrast, the noncellulosomal xylanases hydrolyzed xylan exclusively. beta-Glucosidase and beta-xylosidase activities were shown to be the action of different enzymes; both were associated exclusively with the cell and were not components of the cellulosome. Despite the lack of growth on and utilization of xylan or its degradation products, C. thermocellum produces a highly developed xylanolytic apparatus which is interlinked with its cellulase system.

Various immunochemical techniques were employed to probe the relationship between the extracellular emulsifying agent (emulsan) and the cell-associated form of the polymer in Acinetobacter calcoaceticus RAG-1. Using an emulsan-specific antibody preparation, immunocytochemical labeling revealed that an emulsan-like antigen is a major component of the 125-nm minicapsule which envelopes the exponential-phase cell of the parent strain. The marked reduction of this capsule in stationary-phase cells was correlated with the production of extracellular emulsifying activity. Crossed immunoelectrophoresis techniques demonstrated that the major antigenic component (S1) of the culture supernatant fluid is immunochemically identical to purified emulsan, yet electrophoretically distinct. The characteristics of the parent strain were compared with those of two phage-resistant mutant strains which are defective in extracellular emulsan production. One of these mutants, termed TR3, lacked both the emulsan-like capsule on the cell surface and the extracellular S1 component. A second phage-resistant emulsan-defective mutant (TL4) was characterized by an antigenically altered and inactive form of extracellular emulsan. A relatively small amount of emulsan-like capsular material was consistently demonstrated on the cell surface of this mutant. The correlation between phage sensitivity and extracellular emulsan production was strengthened by the fact that emulsan-specific antibodies inhibited both emulsification activity and phage adsortion onto cells of the parent strain.

The object of this study was to define minimized biotin-binding fragments, or ‘prorecognition sites’, of either the egg-white glycoprotein avidin or its bacterial analogue streptavidin. Because of the extreme stability to enzymic hydrolysis, fragments of avidin were prepared by chemical means and examined for their individual biotin-binding capacity. Treatment of avidin with hydroxylamine was shown to result in new cleavage sites in addition to the known Asn-Gly cleavage site (position 88-89 in avidin). Notably, the Asn-Glu and Asp-Lys peptide bonds (positions 42-43 and 57-58 respectively) were readily cleaved; in addition, lesser levels of hydrolysis of the Gln-Pro (61-62) and Asn-Asp (12-13 and 104-105) bonds could be detected. The smallest biotin-binding peptide fragment, derived from hydroxylamine cleavage of either native or non-glycosylated avidin, was identified to comprise residues 1-42. CNBr cleavage resulted in a 78-amino acid-residue fragment (residues 19-96) that still retained activity. The data ascribe an important biotin-binding function to the overlapping region (residues 19-42) of avidin, which bears the single tyrosine moiety. This contention was corroborated by synthesizing a tridecapeptide corresponding to residues 26-38 of avidin; this peptide was shown to recognize biotin. Streptavidin was not susceptible to either enzymic or chemical cleavage methods used in this work. The approach taken in this study enabled the experimental distinction between the chemical and structural elements of the binding site. The capacity to assign biotin-binding activity to the tyrosine-containing domain of avidin underscores its primary chemical contribution to the binding of biotin by avidin.

The involvement of tyrosine in the biotin-binding sites of the egg-white glycoprotein avidin and the bacterial protein streptavidin was examined by using the tyrosine-specific reagent p-nitrobenzenesulphonyl fluoride (Nbs-F). Modification of an average of about 0.5 mol of tyrosine residue/mol of avidin subunit caused the complete loss of biotin binding. This indicates that the single tyrosine residue (Tyr-33) in the avidin subunit is directly involved in the biotin-binding site and that its modification by Nbs also abolishes the binding properties of a neighbouring subunit. This suggests that the tyrosine residues of the egg-white protein may also contribute to the stabilization of the native protein structure. In streptavidin, however, the modification of an average of 3 mol of tyrosine residue/mol of subunit was required to inactivate completely the biotin-binding activity of the protein, but only 1 mol (average) of tyrosine residue/mol of subunit was protected in the presence of biotin. The difference between the h.p.l.c. elution profiles of the enzymic digests of Nbs-modified streptavidin and the Nbs-modified streptavidin-biotin complex revealed two additional fractions in the unprotected protein that contain Nbs-modified tyrosine residues. These residues, Tyr-43 (major fraction) and Tyr-54 (minor fraction), appear to contribute to the biotin-binding site in streptavidin.

Immobilisation methods of the chiral silicone stationary phase Chirasil-L-Val have been studied. In addition to the standard techniques of radical-induced immobilisation with dicumyl peroxide and azo tert-butane, immobilisation was solely achieved by thermal treatment: conditioning at low flow-rates or under stop-flow conditions led to unexpectedly high immobilisation despite mild temperatures. The presence of water vapor in the carrier gas accelerated the immobilisation process. While up to 75% immobilisation was attainable with both ATB and thermal methods, immobilisation with DCUP did not exceed 50%, despite relatively high DCUP concentrations.

Non-wetting viscous liquids such as oligobutadiene prefer “active” sites such as pores during the process of physisorption. Thus, polybutadiene (PBD) coatings on porous silica do not result in a homogeneous polymer film but in an inhomogeneous loading where the bulk polymer is mainly sited in the pores of the silica. An increasing polymer loading leads to increasingly filled pores instead of a thicker polymer film. We cannot exclude the possibility that most of the surface is covered at least with a thin polymer film since the chromatographic behaviour is relatively good for polypeptides, which are highly susceptible to the silanol groups of silica.

Two different types of porous glass (PG) were submitted to a thermal treatment in a temperature range from 620°C–700°C for 2 to 100 h. The materials thereby obtained have been characterized by static Secondary Ion Mass Spectrometry (SIMS). Special attention was paid to the change of the boron surface concentration. In addition we studied the specific surface area (SBET) dependence on the thermal treatment parameters, such as heating time and heating temperature. Selected PG materials have been modified with organosilanes and characterized prior to their use as packings in RP-HPLC.