bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in phases and crystallinity of plasma‐sprayed hydroxyapatite coatings under heat treatment: A quantitative study
Authors: Wang B. C. , Chang E. , Lee T. M. , Yang C. Y.
Published: May 2005

With three kinds of plasma‐sprayed hydroxyapatite coatings (HACs) prepared, the objectives of this study were (1) to establish the calibration methods for quantitatively measuring the concentration of impurity phases and the degree of crystallinity of the HACs, and (2) to explore the effects of postheat treatments at various temperatures in vacuo on the changes of phases and crystallinity of the HACs. By the internal standard method used, the concentrations of impurity phases, such as α‐TCP, β‐TCP, and TP, of the assprayed HACs were significantly higher than those measured by the direct intensity‐ratio method, and the CaO phase was lower than the direct intensity‐ratio method. When the HACs were heat treated in the temperature interval 630–850°C, the concentrations of impurity phases obviously decreased, and the coating crystallinity apparently increased. After annealing at 850°C, an HAC consisting of at least 95% crystallinity with few impurity phases was obtained. As the annealing temperatures in the interval 850–1000°C were applied, however, the HA phase seriously decomposed, resulting in the appearance of a large number (higher than 20 wt%) of impurity phases in the HACs. This work suggests that the optimum heat treatment conditions in vacuo for maximizing crystallinity and minimizing impurity phases of the HACs do not occur at the same temperature. © 1995 John Wiley & Sons, Inc.
Neovascularization of synthetic membranes directed by membrane microarchitecture
Authors: Brauker James H. , Carr‐Brendel Victoria E. , Martinson Laura A. , Crudele Joanne , Johnston William D. , Johnson Robert C.
Published: May 2005

Transplantation of tissues enclosed within a membrane device designed to protect the cells from immune rejection (immunoisolation) provides an opportunity to treat a variety of disease conditions. Successful implementation of immunoisolation has been hampered by the foreign‐body reaction to biomaterials. We screened a variety of commercially available membranes for foreign‐body reactions following implantation under the skin of rats. Histologic analysis revealed that neovascularization at the membrane–tissue interface occurred in several membranes that had pore sizes large enough to allow complete penetration by host cells (0.8‐8‐μm pore size). When the vascularization of the membrane–tissue interface of 5‐μm‐pore‐size polytetrafluoroethylene (PTFE) membranes was compared to 0.02‐μm‐pore‐size PTFE membranes, it was found that the larger pore membranes had 80–100‐fold more vascular structures. The increased vascularization was observed even though the larger pore membrane was laminated to a smaller pore inner membrane to prevent cell entry into the prototype immunoisolation device. This significantly higher level of vascularization was maintained for 1 year in the subcutaneous site in rats. © 1995 John Wiley & Sons, Inc.
Loading of cells and a possible upper limit of load response with respect to strain energy density
Authors: McDonald F. , Yettram A. L.
Published: May 2005

A model has been established to examine the effects of mechanically loading bone on the ionic distribution in osteocytes. The ionic concentrations are determined from the fluorescence of specific ionic indicators SPFI, PBFI, and SPQ. A deformation was induced in the calvariae of neonatal rats which were used as the experimental subjects. The ionic distribution was not uniform across the calvarial specimen, and with the aid of finite element stress analysis we examined the distribution of strain energy density within the specimen. A similarity between the pattern of distribution of strain energy density and the potassium and sodium ions was observed, whereas this was not the case with chloride ions. © 1995 John Wiley & Sons, Inc.
High surface energy enhances cell response to titanium substrate microstructure
Authors: Zhao G. , Schwartz Z. , Wieland M. , Rupp F. , Geis‐Gerstorfer J. , Cochran D. L. , Boyan B. D.
Published: May 2005

Titanium (Ti) is used for implantable devices because of its biocompatible oxide surface layer. TiO2 surfaces that have a complex microtopography increase bone‐to‐implant contact and removal torque forces in vivo and induce osteoblast differentiation in vitro. Studies examining osteoblast response to controlled surface chemistries indicate that hydrophilic surfaces are osteogenic, but TiO2 surfaces produced until now exhibit low surface energy because of adsorbed hydrocarbons and carbonates from the ambient atmosphere or roughness induced hydrophobicity. Novel hydroxylated/hydrated Ti surfaces were used to retain high surface energy of TiO2. Osteoblasts grown on this modified surface exhibited a more differentiated phenotype characterized by increased alkaline phosphatase activity and osteocalcin and generated an osteogenic microenvironment through higher production of PGE2 and TGF‐β1. Moreover, 1α,25(OH)2D3 increased these effects in a manner that was synergistic with high surface energy. This suggests that increased bone formation observed on modified Ti surfaces in vivo is due in part to stimulatory effects of high surface energy on osteoblasts. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
Substratum roughness alters the growth, area, and focal adhesions of epithelial cells, and their proximity to titanium surfaces
Authors: Baharloo B. , Textor M. , Brunette D. M.
Published: May 2005

Epithelial (E) cells were cultured on smooth tissue culture plastic (TCP), TCP‐Ti, polished Ti (P), and rough grit‐blasted Ti (B), acid‐etched Ti (AE), and grit‐blasted and acid‐etchedTi (SLA) surfaces and their growth, area, adhesion, and membrane‐Ti proximity assessed. Rough surfaces decreased the growth of E cells compared to smooth surfaces in cultures up to 28 days. In general rough surfaces decreased the spreading of E cells as assessed by their area with the most pronounced affect for the SLA surface. On the other hand, the strength of E cells adhesion as inferred by immunofluorescence staining of vinculin in focal adhesions indicated that E cells formed more and larger focal adhesions on the smooth P surface compared to the rougher AE surface. As this finding indicates a stronger adhesion to smooth surfaces, it is likely that E cells on rough surfaces are more susceptible to mechanical removal. An immunogold labeling method was developed to visualize focal adhesions using back‐scattered electron imaging with a scanning electron microscope (SEM). On rough surfaces focal adhesions were primarily localized on to the ridges rather than the valleys and the cells tended to bridge over the valleys. Transmission electron microscopy (TEM) measurements of membrane proximity to the Ti surface indicated that average distance of cell to the Ti increased as the Ti surface roughness increased. Therefore, the size and shape of surface features are important determinants of epithelial adhesive behavior and epithelial coverage of rough surfaces would be difficult to attain if such surfaces become exposed. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2005
The isocitrate dehydrogenase phosphorylation cycle: Regulation and enzymology
Authors: Laporte David C.
Published: May 2005

Isocitrate dehydrogenase (IDH) of Escherichia coli is regulated by phosphorylation and dephosphorylation. This phosphorylation cycle controls the flow of isocitrate through the glyoxylate bypass, a pathway which bypasses the CO2 evolving steps of the Krebs' cycle. IDH is phosphorylated at a single serine which resides in its active site. Phosphorylation blocks isocitrate binding, thereby inactivating IDH. The IDH phosphorylation cycle is catalyzed by a bifunctional protein kinase/phosphatase. The kinase and phosphatase reactions appear to be catalyzed at the same site and may share some catalytic steps. A variety of approaches have been used to examine the IDH phosphorylation cycle in the intact organism. The picture which has emerged is one of an exquisitely sensitive and flexible system which is capable of adapting efficiently to the environment both inside and outside the cell. © 1993 Wiley‐Liss, Inc.
Gene regulation by phosphate in enteric bacteria
Authors: Wanner B. L.
Published: May 2005

The Escherichia coli phosphate (PHO) regulon includes 31 (or more) genes arranged in eight separate operons. All are coregulated by environmental (extra‐cellular) phosphate and are probably involved in phosphorus assimilation. Pi control of these genes requires the sensor PhoR, the response regulator PhoB, the binding protein‐dependent Pi‐specific transporter Pst, and the accessory protein PhoU. During Pi limitation, PhoR turns on genes of the PHO regulon by phosphorylating PhoB that in turn activates transcription by binding to promoters that share an 18‐base consensus PHO Box. When Pi is in excess, PhoR, Pst, and PhoU together turn off the PHO regulon, presumably by dephosphorylating PhoB. In addition, two Pi‐independent controls that may be forms of cross regulation turn on the PHO regulon in the absence of PhoR. The sensor CreC, formerly called PhoM, phosphorylates PhoB in response to some (unknown) catabolite, while acetyl phosphate may directly phosphorylate PhoB. Cross regulation of the PHO regulon by CreC and acetyl phosphate may be examples of underlying control mechanisms important for the general (global) control of cell growth and metabolism. © 1993 Wiley‐Liss, Inc.
Low fluences of ultraviolet irradiation stimulate hela cell surface aminopeptidase and candidate “TGFαase” activity
Authors: Brown S. B. , Krause D. , Ellem K. A. O.
Published: May 2005

Several forms of perturbation result in the release of bioactive molecules into the microenvironment of injured cells to mediate the inflammatory or reparative reactions which restore normal tissue structure and function. Amongst other products, ultraviolet irradiation (UV) causes the release of the growth factor TGFα from a variety of epithelial cell sources, apparently by a post‐translational mechanism. Here we have explored the hypothesis that UV results in the activation of cell surface proteases which may then be capable of excising mature TGFα from its plasma membrane‐bound precursor. Using a recently described, sensitive assay of peptidase activity tailored to the substrate requirements for cleavage of the scissile bonds in proTGFα, we have found that nonlethal fluences of UV ( < 12 Jm−2) to HeLa cell cultures are followed by large increases in cell surface proteolytic activities. Amongst these, endopeptidase activity produces a similar product profile from the nonapeptide substrate to that of human leukocyte elastase, an enzyme previously shown to be capable of releasing a bioactive, mature form of TGFα from its cell‐bound precursor. However, in addition to this candidate “TGFase” activity, cell surface aminopeptidase activity was also very significantly increased. The increase in the two classes of peptidase function differed in the timing of their responses. Aminopeptidase activation occurred immediately following UV, peaking after some 15–20 h, whereas the increase in endopeptidase activity lagged 6 h behind, cresting after 20–24 h. No evidence for a role for aminopeptidase in the activation of the endopeptidase could be found. Also, there was no increase in the total proteolytic activity demonstratable in cell extracts following UV.

Attempts to interrupt the UV peptidase activation by inhibiting protein synthesis with cycloheximide were unsuccessful; rather, the inhibitor itself caused an increase in both classes of peptidase activity during the first 20 h. Unlike the UV response, both the aminopeptidase and endopeptidase ectoactivities increased simultaneously within a few hours of introducing cycloheximide into the medium of unirradiated cultures. The cycloheximide induced activity peaked after 20 h. Interestingly, cycloheximide alone has previously been shown to potentiate TGFα release from a cell line producing its precursor constitutively.

These data suggest that both UV and cycloheximide can initiate reactions in HeLa cells which result in ectopeptidase activation of a global nature. Since both agents result in rapid interruption of DNA synthesis, it is possible that this cell surface proteolytic response may be analogous to, or part of, the “mammalian genetic stress response.” The mechanism of the activation of the cell surface proteases appears to be post‐translational, perhaps part of a proteolytic cascade originating from perturbed macromolecular synthesis. © 1993 Wiley‐Liss, Inc.
Developing and implementing a comprehensive approach to serving women with co‐occurring disorders and histories of trauma
Authors: Huntington Nicholas , Moses Dawn Jahn , Veysey Bonita M.
Published: May 2005

The Substance Abuse and Mental Health Services Administration (SAMHSA) funded the Women, Co‐Occurring Disorders and Violence Study to generate empirical knowledge on how to improve services for women who are trauma survivors and have co‐occurring mental health and substance use disorders. We first review the literature on the pervasiveness of trauma among women and the ways in which current service systems fail to address their needs. We then describe the four core principles of the model grantees developed to test in the project. Working through a project Steering Committee, grantees mandated that services be (a) integrated, (b) trauma‐informed, (c) consumer‐involved, and (d) comprehensive. For each of these principles, we describe the specifications adopted by the committee, the strategies the study sites used to implement the principle in their local settings, and the concrete lessons sites learned concerning how to implement the principle. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 395–410, 2005.
Children of mothers with histories of substance abuse, mental illness, and trauma
Authors: VanDeMark Nancy R. , Russell Lisa A. , O'Keefe Maura , Finkelstein Norma , Noether Chanson D. , Gampel Joanne C.
Published: May 2005

Children exposed to parental substance abuse, mental illness, and violence face profound challenges, including increased risk for emotional and behavioral problems, substance abuse, and victimization. In this article, we describe the characteristics of a sample of children of women entering treatment. These children had been exposed to domestic violence, frequent child welfare involvement, and residential instability. Parental entry into treatment affords treatment providers an opportunity to intervene early with these children, enabling them to offer supportive and preventive services and to help children build skills to avoid problems later. Treatment providers are encouraged to offer assessment and services to children of parents entering treatment, capitalizing on the opportunity to intervene early with a group of children who are at risk for problems with significant individual and social consequences. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 445–459, 2005.
Women's recollections of victimization, psychological problems, and substance use
Authors: Gatz Margaret , Russell Lisa A. , Grady Janice , Kram‐Fernandez Debra , Clark Colleen , Marshall Brenda
Published: May 2005

In this article, we describe types of physical and sexual abuse that women report and some consequences of these experiences in their lives. Research questions focused on types of abuse, the age at which abuse was experienced, and correlations between abuse and other outcomes. Data were collected from 2,729 participants in the Women, Co‐Occurring Disorders and Violence Study. Results showed that two thirds of participants described their sexual and/or physical abuse as beginning before age 18. Earlier onset was related to more severe current mental distress on the Brief Symptom Inventory. In general, reported age of onset for sexual and/or physical abuse was before onset of substance use. The implication for treatment of mental health disorders and substance use disorders is that interventions that account for abuse and its correlates may be more successful than interventions that do not assess for or attend to issues of abuse. © 2005 Wiley Periodicals, Inc. J Comm Psychol 33: 479–493, 2005.
Solvent extraction equilibrium of gallium from hydrochloric acid solutions by Amberlite LA‐2
Authors: Gutiérrez Beatriz , Pazos Carmen , Coca José
Published: May 2005

The extraction of Ga(III) from chloride solutions by Amberlite LA‐2 dissolved in kerosene at 25°C has been investigated. The effects of the concentrations of gallium, chloride and Amberlite LA‐2, and pH, on the equilibrium are reported. Extracted complexes are formulated using a slope analysis of the equilibrium data. All gallium was back‐extracted from the loaded organic phase with water.
Practical capillary gas chromatography—a systematic approach
Authors: Grob K. , Grob G.
Published: May 2005

Capillary gc is now rapidly expanding. Naturally, initiation is most often attempted on the basis of the experience acquired with packed columns. However, such an extrapolation is successful only if a number of essential peculiarities of capillary gc are considered. Based on practical examples this paper discusses six essential details: 1) design and maintenance of the gas flow paths, 2) the greatly increased importance of sampling technique, which should not be confined just to stream splitting, 3) the problems in quantitative analysis arising from small sample size, 4) specific sources of trouble related to small amounts of liquid phase, 5) specific arguments for the choice of the carrier gas, clearly pointing to hydrogen as the ideal carrier and, 6) the different way to approach column production. Figures for all selected examples are given.
High performance liquid chromatography with electrochemical detection. 1: Separation of Cannabis constituents and quantitation of Δ9 tetrahydrocannabinol
Authors: Masoud A. N. , Wingard D. W.
Published: May 2005

A simple, isocratic high performance liquid chromatography system (HPLC) with electrochemical detection (EC) was used to study Cannabis constituents. Several Cannabis extracts and reference standards were examined. A total of eleven constituents were separated, and three major cannabinoids; Δ8, Δ9 tetrahydrocannabinol (THC) and cannabidiol (CBD) were identified. A linear relationship was established for the quantitation of the halucinogenic constituent Δ9 THC. Minor contaminants in Δ9 THC reference standard, which were not detected by gas chromatography (GC) were detected for the first time. The detection limits of Δ9 THC and related cannabinoids were in the low nanogram range (2–20 ng).
Comparison of optical in‐situ scanning of conventional and high‐performance thin‐layer chromatograms
Authors: Jänchen D. , Schmutz H. R.
Published: May 2005

Conventional TLC, linear and circular HPTLC are compared by using In‐situ reflectance measurements. Chromatographic resolution, time requirement and reproducibility of quantitative scanning of the different TLC methods are investigated by means of three separation problems: benzodiazepines, corticosteroids, polycyclic aromatic hydrocarbons.

In all three application examples, which were chosen without prejudice, the circular developing mode with subsequent quantitative scanning showed certain advantages over the corresponding linear HPTLC techniques. These were in the case of

Benzodiazepines: Better reproducibility of quantitative assessment.

Corticosteroids: Better resolution and slightly better quantitative reproducibility.

Polycyclic aromatic hydrocarbons: Chromatography considerably faster.
Trace elements in HPLC silica gel
Authors: Verzele M. , De Potter M. , Ghysels J.
Published: May 2005

Trace elements in different silica gels are determined by neutron activation analysis. The presence of 20 elements in the ppm range and of 15 elements in the ppb range is established in all silica gels; even in spherical material probably obtained via an organosilicium starting material. Removal of these elements by acid treatment before and after derivatization to a reversed‐phase is studied. This is only partially effective. The resulting HPLC phases are, however, much better in cases where trace elements are detrimental. Even octadecyl derivatized silicagel can withstand boiling in 12 N hydrochloric acid without loosing significant amounts of bonded organic material.
An integrated GC/FT‐IR system for the analysis of environmental pollutants
Authors: Azarraga L. V. , Potter C. A.
Published: May 2005

An integrated gas chromatography/Fourier transform infrared spectrometry (GC/FT‐IR) system developed for the analysis of environmental pollutants is described. The versatility of the system allows the utilization of many different techniques of sample introduction and manipulation during analysis. The sample can be introduced by direct injection or thermal desorption from an adsorbent cartridge, and can then be separated on one of two capillary columns and detected by FT‐IR or an FID. Cold traps and collection cartridges incorporated in the system permit recovery and additional fractionation of samples. Recovered sample and sample fractions can then be re‐analyzed by GC/FT‐IR or subsequently analyzed by GC/MS or other methods.
Autocrosslinkable methyl‐2‐phenylethylpolysiloxane stationary phase for capillary column gas chromatography
Authors: Bradshaw J. S. , Crowley S. J. , Harper C. W. , Lee M. L.
Published: May 2005

Methyl‐2‐phenylethylpolysiloxane polymers have been synthesized for comparison with methylphenylpolysiloxane stationary phases for gas chromatography. The 50% 2‐phenylethyl polysiloxane was found to be autocrosslinkable at 260°C without addition of free redical initiator. Although the selectivity of this phase appears to be similar to the 50% phenyl polysiloxane, its thermal stability is not as high.
Capillary gas chromatography of amino acids as their tert‐butyldimethylsilyl derivatives in the analysis of serum amino acids in metabolic diseases
Authors: Chaves Das Neves H. J. , Vasconcelos A. M. P. , Tavares J. Rueff , Ramos P. Nogueira
Published: May 2005

Reaction of amino acids with N‐methyl‐N‐(tert‐butyldimethylsilyl)trifluoroaceamide (MTbSTFA) in acetonitrile affords good yields of amino acid derivatives with excellent gas chromatographic and mass spectrometric properties. The single‐step derivatization procedure is highly reproducible. The TBDMS amino acids are stable at room temperature for at least three days. Only a single peak is observed for each amino acid. The procedure allows simultaneous analysis of asparagine and glutamine together with other serum amino acids. Separation is achieved on a borosilicate glass capillary coated with OV‐1. The mass spectra of the TBDMS amino acids possess characteristic diagnostic ions. These properties were used in the sensitive detection by GC‐MS and SIM‐GC‐MS of GABA and pipecolic acid in the serum of a newborn suspected of a Zellweger‐type syndrome, which could not be detected by other methods.
Direct sample injection in supercritical fluid chromatography with packed fused silica column
Authors: Hirata Y. , Nakata F. , Horihata M.
Published: May 2005

A direct sample injection technique was developed for supercritical fluid chromatography in a packed capillary column, with carbon dioxide as mobile phase and a flame ionization detector. The method allowed solutions, neat liquids, and even solids to be introduced as samples. Also, extraction with supercritical carbon dioxide was combined with this method to separate polymer additives.
Evaluation of automated and manual hot‐splitless, cold‐splitless (PTV), and on‐column injection technique using capillary gas chromatography for the analysis of organophosphorus pesticides
Authors: Stan H.‐J. , Müller H.‐M.
Published: May 2005

Three different injection modes were compared for the analysis of organophosphorus pesticides. Differing results were found for several compounds depending on their chemical structure and thermostability. The programmed temperature vaporizing injector used in this study seemed to be the most promising sampling device for pesticide residue analysis in biological samples.
Supercritical fluid extraction‐capillary gas chromatography: On‐line coupling with a programmed temperature vaporizer
Authors: Houben Robert J. , Janssen Hans‐Gerd M. , Leclercq Piet A. , Rijks Jacques A. , Cramers Carel A.
Published: May 2005

A simple and versatile system is described for the on‐line coupling of SFE to capillary GC. The interfacing consists of a programmed temperature vaporizer (PTV) injector. With this injector it is possible to combine solute trapping, elimination of a high flow of extraction fluid, and quantitative transfer of solutes to the seperation column. The problems caused by impurities in the extraction fluid in on‐line SFE‐GC are discussed. Simple methods are described for the purification of commercially available carbon dioxide. The trapping efficiency of the PTV injector is studied. Applications of the SFE‐PTV‐GC system are given for the analysis of polymer anti‐degradants, polar compounds, and samples with environmental relevance.
Preparation, purification, and analysis of alkylated cyclodextrins
Authors: Schomburg Gerhard , Deege Alfred , Hinrichs Heike , Hübinger Eduard , Husmann Heribert
Published: May 2005

Methods of alkylation of α‐, β‐ and γ‐cyclodextrins have been optimized with regard to the parameters of reaction, degree of alkylation and yields. The analysis of the reaction mixtures and of the isolated single species has been performed by high temperature GC and HPLC. The phase systems of the preferably applied HPLC have been carefully adjusted by variation of both the stationary and mobile phases to the very different hydrophobicities of the various alkylated CD species which have been synthesized. Several partially or fully alkylated CD species were isolated from preparative scale HPLC separations in high purity.
Stereoisomeric flavor compounds, part LVIII: The use of heptakis(2,3‐di‐O‐methyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin as a chiral stationary phase in flavor analysis
Authors: Dietrich Armin , Maas Birgit , Messer Wilhelm , Bruche Günther , Karl Volker , Kaunzinger Astrid , Mosandl Armin
Published: May 2005

The characteristics of the new chiral stationary phase heptakis(2,3‐di‐O‐methyl‐6‐O‐tert‐butyldimethylsilyl)‐β‐cyclodextrin are outlined and compared with permethyl‐ and perethyl‐β‐cyclodextrins.
Call for fused silica tubing furnishing tight press‐fit connections
Authors: Grob Konrad , Biedermann Maurus , Bernath Konrad , Neukom Hans‐Peter , Galli Mario
Published: May 2005

Recently introduced fused silica, primarily of the high temperature type, no longer allows the formation of a reliable press‐fit seal. Attempts to tighten the connection with various kinds of glue proved unsatisfactory. Manufacturers of fused silica tubing are urged to devote more attention to the problem.
Automated analysis of polar pesticides in water by on‐line solid phase extraction and gas chromatography using the co‐solvent effect
Authors: Noij Theo H. M. , van der Kooi Margo M. E.
Published: May 2005

In order to meet the requirements of analyzing very low concentrations of pesticides in water (typically at 0.1 μg/l or less), samples have to be concentrated prior to GC‐analysis. Samplie pre‐concentration by off‐line methods based on solid phase extraction (SPE) or liquid‐liquid extraction are very time consuming and cumbersome. Moreover, the quantitative performance of the analytical method as a whole in terms of accuracy and reliability is seriously hindered by elaborate, manually performed sample pre‐treatment steps. This paper describes an automated method based on solid phase extraction and capillary gas chromatography. The technique was applied for the analysis of 31 polar organophosphorus and organonitrogen pesticides. A commercially available HPLC/GC instrument is modified, using the LC‐part for solid phase extraction. The sample, of which only a few ml's is required to obtain sufficiently low detection limits, is delivered by a robotic large volume autosampler. After solid phase extraction and elution, the eluate is transferred into the GC via a so called “loop type interface”. In this paper the instrumentation and analytical methodology is described, as well as the main validation results. The quantitative performance (i.e. recovery and repeatability) of the most polar solutes like metamitron and dimethoate appears to be better than obtained with off‐line SPE as a result of the more beneficial ratio between the amount of sorbent and the sample volume. As the loop‐type interface causes losses of the most volatile compounds, a co‐solvent is added. This co‐solvent provides sufficient trapping capacity in the capillary pre‐columns to allow quantitative analysis of even the most volatile pesticides. Moreover a better separation of early eluting compounds is also established.
Enhanced selectivity in the determination of trianzines in environmental samples by Benchtop CGC‐MS‐MS
Authors: Sandra Pat , Beltran Joachim , David Frank
Published: May 2005

Some triazines and metabolities have been analyzed in water and soil samples, at the 0.1 and 10 ppb level, respectively, by CGC‐MS and CGC‐MS‐MS using an ion trap detector (ITD). The sample preparation consisted of SPE on LiChrolut EN cartridges for water samples, and of ultrasonic treatment followed by SPE for soil samples. Recoveries were in the order of 90%. The advantage of MS‐MS compared to MS operation of the ITD, is the enhanced selectivity resulting in more precise determinations. The metabolites of atrazine and metribuzin have also been studied. Desethylatrazine and desamino‐metribuzin are the main metabolites.
In‐situ deactivation of packed columns for SFC
Authors: Zhang Shigang , Schindler Brigitte , Nicholson Graham , Bayer Ernst
Published: May 2005

Residual adsorptive activity of reversed phase (RP) column packings used in supercritical fluid chromatography (SFC) can be significantly reduced by a dynamic in‐situ silanization with diphenyltetramethyldisilazane (DPTMDS). RP‐materials thus deactivated were characterized both chromatographically and by solid‐phase 29Si NMR.
Analysis of monoterpenes from conifer needles using solid phase microextraction
Authors: Schäfer Brit , Hennig Peter , Engewald Werner
Published: May 2005

The applicability of solid phase microextraction (SPME) to the headspace analysis of monoterpene hydrocarbons from conifer needles was examined. To this end, the influences of fiber coating thickness, exposure time, and exposure temperature on the enrichment of the different monoterpene hydrocarbons were investigated. The distribution constants between polydimethylsiloxane fiber and gas phase at a given temperature were found to be very different. A relation is therefore derived to calculate the distribution constants of substances not available from their Kováts retention indices. A slightly different approach could be the use of so‐called “relative distribution factors”, not considering the actual volume of fiber coating. In view of the different enrichment conditions in SPME as well as the general problems of headspace analysis, a comparison with a completely different method of sample preparation is presented. Furthermore, some applications of SPME to the analysis of monoterpenes from pine needles are given.
Factors affecting the reproducibility and reliability of retention simulation in any form of temperature programmed capillary GC
Authors: Guan Yafeng , Li Linge , Zhou Liangmo
Published: May 2005

Conversion of Kováts retention indices on a given stationary phase into the thermodynamic parameters of compounds on a given column leads to a simplified method for retention simulation in isothermal, linear, and multi‐ramp temperature programmed capillary gas chromatography. The influence of numerical methods used in the computation, the temperature coefficient of Kováts indices, and the experimental factors such as isothermal temperatures selected in the measurement of n‐alkanes, column characterization and sample overloading, on the reproducibility and accuracy of simulation were discussed and examined. When the column used is properly characterized, the error between the simulated values and the experimental data is within ± 0.5 index unit or less than ± 1% of retention time.
Investigation of the solid‐ and solution‐phase binding reactivities of continuous epitopes recognized by polyclonal guinea‐pig anti‐recombinant bovine growth hormone antisera
Authors: Beattie James
Published: May 2005

We have used the technique of multiple pin peptide synthesis to identify three major continuous epitopes in the recombinant bovine (rb) GH molecule. We have synthesized these peptides, residues 24–40, 139–152 and 179–189, as N‐terminally acetylate, C‐terminal amides and confirmed their reactivity in a standard solid‐phase ELISA. Subsequently, for epitope 139–152, we have synthesized a peptide affinity column and used this to isolate antibodies with this epitospe specificity from whole antiserum. In addition, we demonstrate that under native conditions in a liquid phase RIA, these antibodies will precipitate [125I]rbGH. Further, peptide 139–152 itself also cross‐reacts in an rbGH RIA inhibiting binding by up to 20%. Our data suggest that during the immune response to rbGH RIA in guinea‐pigs a substantial part of the B‐cell response is directed to the 139–152 region and that this part of the protein is a native epitope.
Binding of the kunitz‐type trypsin inhibitor DE‐3 from Erythrina caffra seeds to serine proteinases: a comparative study
Authors: Onesti Silvia , Matthews David J. , Aducci Patrizia , Amiconi Gino , Bolognesi Martino , Menegatti Enea , Ascenzi Paolo
Published: May 2005

The effect of pH and temperature of kinetic and thermodynamic parameters (i.e.,kon,koff,Ka, δGo, δHo and δSo values) for the binding of the kunitz‐type trypsin inhibitor DE‐3 from Erythrina caffra seeds (ETI) to bovine β‐trypsin, bovine α‐chymotrypsin, the human tissue plasminogen activator, human α‐, β‐ and γ‐thrombin, as well as the Mr 33000 and Mr 54 000 species of the human urinary plasminogen activator (also named urokinase) has been investigated. At pH 8.0 and 21.0 °C: (i) values of the second‐order rate constant (Kon) for the proteinase: ETI complex formation vary between 8.7 × 105 and 1.4 × 107/M/s; (ii) values of the dissociation rate constant (koff) for the proteinase: ETI complex destabilization range from 3.7 × 10−5 to 1.4 × 104/s; and (iii) values of the association equilibrium constant (Ka) for the proteinase: ETI complexation change from < 1.0 × 104 to 3.8 × 1011/M. Thus, differences in koff values account mostly for the large changes in Ka values for ETI binding. The affinity of ETI for the serine proteinases considered can be arranged as follows: bovine β‐trypsin > human tissue plasminogen activator > bovine β‐chymotrypsin » human α‐, β‐ and γ‐thrombin ≈︁ o Mr 33 000 and Mr 54000 species of the human urinary plasminogen activator. Moreover, the serine proteinase: ETI complex formation is an endothermic, entropy‐driven, process. On increasing the pH from 5.0 to 9.0 (at 21.0 °C), the affinity of ETI for bovine β‐trypsin, the human tissue plasminogen activator and bovine α‐chymotrypsin (i.e., Ka values) increases, thus reflecting the acidic‐pK shift of the His57 catalytic residue from ≈︁≈︁ 7.0, in the free enzymes (pKUNL), to ≈︁5.2, in the serine proteinase: ETI complexes (pKLIG). The ETI‐binding properties have been analysed in parallel with those of related serine (pro)enzyme/macromolecular inhibitor systems. Considering the known molecular models, the observed binding behaviour of ETI is discussed in relationship to the inferred stereochemistry of the serine proteinase/inhibitor contact regions.
The infrared and Raman spectra of perchloro‐[4] ‐ radialene
Authors: Finseth Dennis H. , Miller Foil A.
Published: May 2005

Infrared and Raman spectra are reported for polycrystalline perchloro‐[4]‐radialene and for solutions in CCl4 and CS2. An earlier X‐ray structure determination by van Remoortere and Boer has shown that in the crystal the molecular symmetry is almost D2d (puckered ring), but is slightly distorted to C2. This distortion was attributed to crystal packing forces. The vibrational spectrum does not show the distortion. The spectra are essentially the same for polycrystalline solid as for solution, and are completely compatible with D2d in both states. Assignments are made for a few of the modes where evidence warrants it. Some observations are also made about the mass spectrum, which has a rich structure because of the many isotopic species.
Resonance Raman spectra of Cu‐porphin‐d4(meso) and Ni‐porphin, and the infrared spectrum of Cu‐porphin‐d4
Authors: Verma A. L. , Asselin M. , Sunder S. , Bernstein H. J.
Published: May 2005

The resonance Raman spectra are presented for Ni‐porphin and Cu‐porphin‐d4(meso) as dilute solutions in CS2 and C2Cl4 using an Ar+ laser and a tunable Rhodamine 6G dye laser. The Raman features are assigned to the different vibrational species on the basis of their depolarization data. The assignment of 14 features in the spectrum of Cu‐porphin‐d4 and 13 features in the spectrum of Cu‐porphin and Ni‐porphin is discussed by comparing the spectra of the three molecules. Also the infrared spectrum of Cu‐porphin‐d4 as a solid dispersed in CsI matrix is reported for the 200–2000 cm−1 region.
On the value of the depolarization ratio of fundamentals of sandwich compounds with an electronically degenerate ground state
Authors: Koningstein J. A. , Aleksanyan V. T.
Published: May 2005

The selection rules are derived for the Raman activity of fundamental modes in electronically degenerate groundstates of sandwich compounds. Emphasis is placed on the occurrence of asymmetric tensors, which can result in values of the depolarization ratio of Raman bands larger than 3/4.
Resonance Raman spectra of p‐hydroxyazobenzene and its ring deuterated derivatives in the strongly acidic solution
Authors: Machida Katsunosuke , Lee Hohi , Saito Yutaka , Uno Toyozo
Published: May 2005

Resonance Raman spectra of p‐hydroxyazobenzene (HAB) and its three ring deuterated derivatives have been measured in the strongly acidic solution. The observed Raman bands have been assigned by referring to the spectra of related compounds and the deuteration effect. The NN stretching band of HAB in the solution of 20% hydrochloric acid undergoes a high frequency shift by about 60 cm−1 on changing the solvent to 20% deuterochloric acid. In the strongly acidic solution HAB has been confirmed to exist as a resonance hybrid between the azo and the hydrazone forms, of which the former is predominant. A normal coordinate analysis of a simplified model, CNHNC6H4pOH, has been carried out to give a good agreement between the calculated and the observed frequencies.
A computer controlled high resolution Raman spectrometer system
Authors: Fletcher William H. , Rayside John S. , McLendon William B.
Published: May 2005

The design and performance of a computer controlled high resolution scanning Raman spectrometer system is described. Resolution of 0.05 cm−1 has been achieved with vibration‐rotation bands with single mode laser operation. Pure rotation lines have been observed with 0.04 cm−1 slit widths.
Resonance Raman spectra of platinum ethylenediamine complexes
Authors: Papavassiliou G. C. , Theophanides T.
Published: May 2005

The resonance Raman spectra (RRS) of PtenX3 and the Raman spectra (RS) of PtenX2 and PtenX4, where X = Cl or Br, have been studied. The progression of the symmetric fundamental ν1,…XPt(IV)X…Pt(IV)X…of PtenX3 up to 10ν1 and the ωe and χe values have been found to be 304.1 and 0.7 cm−1, for the chloro and 175.1 and 0.4 cm−1 for the bromo derivative. The dissociation bond energies of XPt(IV) are found to be 94 and 54 Kcal, respectively.
Observation of Br2 stretch modes of adsorbed molecules on various substrates
Authors: Bernussi A. A. , Gualberto G. M.
Published: May 2005

We report the observation of the Raman modes of Br2 molecules bound to graphite, KBr and fused quartz substrates. The results demonstrate that Br2 bonds to surfaces at preferred sites, except in the case of fused quartz, where no unique site can be defined owing to its amorphous nature. The spectra of Br2 on the KBr substrate, taken at later times, exhibit modes that are related to a chemical modification of the KBr substrate.
Raman spectral studies at rotating pyrolytic graphite electrodes
Authors: McQuillant A. J. , Hester R. E.
Published: May 2005

Raman spectra of highly oriented pyrolytic graphite electrodes with the basal plane exposed (BPG) and the basal plane edges exposed (EPG) have been investigated in aqueous acidic media using a rotating electrode cell. Anodic oxidation of these electrodes and subsequent reduction resulted in the original sharp band at 1581 cm−1 being replaced by a broader band at ca 1600 cm−1 with a new broad band associated with disordered carbon emerging in the 1300–1400 cm−1 region. The Raman spectrum of multilayers of thionine (3,7‐ diaminophenothiazinium chloride) electrodeposited on BPG electrodes has been recorded. The spectral sensitivity has been found to be such that monolayer detection is unlikely at this electrode.
Raman spectra of solid films 3—Mg, Cu and Zn phthalocyanine complexes
Authors: Jennings Carol , Aroca Ricardo , Hor Ah‐Mee , Loutfy R. O.
Published: May 2005

Thin solid films of Mg, Cu and Zn phthalocyanine complexes have been studied using Raman spectroscopy. Laser excitation lines near resonance and in resonance with the electronic absorption band of the substrate have been used. A description of vibrational modes is given and correlations in vibrational properties of the series are discussed.
On the theory of the dominant artefacts in natural and magnetic Raman optical activity
Authors: Barron L. D. , Vrbancich J.
Published: May 2005

The molecular theory of the scattering of polarized light is applied to the problem of the artefacts that frequently arise in Raman circular intensity difference measurements. By including the effect of the finite solid angle in the cone of collected light, a detailed understanding of the major sources of artefacts in polarized and depolarized measurements, and their dependence on the polarization characteristics of the Raman band, is obtained. Inclusion of both antisymmetric and symmetric scattering contributions reveals why magnetic are usually less susceptible to artefacts than natural Raman optical activity spectra.
Polaritons in complex bulk media
Authors: Anikiev A. A. , Reznik L. C. , Umarov B. S. , Scott J. F.
Published: May 2005

Theory and experiment for phonon‐like polaritons in complicated bulk media are discussed. The media include crystals with diffusion, such as ionic conductors, in which the theoretical approaches of Merten and Borstel, Nakamura and Barker and London are compared; systems having polariton anomalies in the frequency region in which the two‐phonon density of states peaks, such as ammonium chloride and calcite; and lithium niobate with optical damage.
Raman spectra of polycrystalline SmBr3 and single crystal NdBr3
Authors: Wilmarth W. R. , Begun G. M. , Daniel J. F. , Hart R. C. , Nave S. E. , Peterson J. R.
Published: May 2005

Raman spectra of polycrystalline NdBr3 and SmBr3 were recorded at room temperature and pressure and polarized Raman spectra of single crystal NdBr3 were also measured. Based on these polarized spectra, symmetry assignments of eight Raman‐active modes were made. The assignments are useful in interpreting the phonon Raman spectra of these and other compounds which exhibit the PuBr3‐type orthorhombic structure and in identifying this structure type quickly by Raman spectroscopy.
Raman spectra of porcine mitochondrial malate dehydrogenase
Authors: Hall William H. , Jagodzinski Paul W.
Published: May 2005

Raman spectra of porcine mitochondrial malate dehydrogenase have been collected and analysed. The existence of weak hydrogen bonds is indicated by the intensity ratio of the tyrosine doublet and a band is found which can be attributed to disulfide bonds. The observed frequencies in the amide I and III regions favor significant contributions from α‐helix and random conformations. An analysis of the intensities using standard methods predicts a very low β‐sheet content.
Raman and infrared spectra of the solid chlorofluorocarbons. II–Dichlorodifluoromethane
Authors: Leblanc L. M. , Anderson A.
Published: May 2005

Raman and infrared spectra of solid dichlorodifluoromethane were recorded in both the internal and lattice mode regions at temperatures between 20 and 80 K. The lattice spectra suggest that the unit cell is small and noncentrosymmetric, and a bimolecular tetragonal cell with factor group C4 is compatible with the observed results. Plausible assignments of all main spectroscopic features are presented, and splittings of internal modes are interpreted in terms of isotopic, crystal, field, Fermi resonance and LO–TO effects.
Normal coordinate analysis and vibrational assignments of 1,1,3,3‐tetramethyldisiloxane
Authors: Gnado J. , Dhamelincourt P.
Published: May 2005

Raman and infrared spectra of liquid 1,1,3,3‐tetramethyldisiloxane were recorded in the ranges 100–3500 and 400–4000 cm−1, respectively. A normal coordinate analysis based on a generalized valence force field was carried out. Using the potential energy distributions and the atomic displacements, this investigation permitted a reasonable interpretation of the observed vibrational modes and a description of the coupling of these modes in the 100–1500 cm−1 region where the spectra exhibit a complex structure.
Vibrational spectra of the cis and trans isomers of the Mo(CO)4(PPh3)2 complex
Authors: Shamir J. , Givan A. , Ardon M. , Ashkenazi G.
Published: May 2005

Raman and infrared spectra of polycrystalline cis and trans isomers of the Mo(CO)4(PPh3)2 complex were recorded at room temperature. The molecular vibrations around the central Mo atoms and the carbonyl ones were assigned and correlated with the group theoretical treatment. Some changes in the spectra of the triphenylphosphine ligand have also been discussed.
Rotational contributions to polarizability derivatives from Raman spectra
Authors: Dudev T. , Galabov B.
Published: May 2005

A procedure for the evaluation of rotational correction terms to polarizability derivatives from Raman spectra with respect to symmetry vibrational coordinates is described. The formulation developed is illustrated with calculations on a number of molecules.
Raman spectra, absolute Raman intensities and electro‐optical parameters of pertechnetate, perrhenate and periodate ions in aqueous solution
Authors: Eysel Hans H. , Kanellakopulos Basil
Published: May 2005

Complete Raman spectra of all four fundamentals of pertechnetate, perrhenate and periodate ions in aqueous solution were measured and calibrated against NaClO4, as an external standard. Electro‐optical parameters for the TcO, ReO and IO bonds were calculated. Changes in the previously published force fields were necessary to adjust the eigenvectors to the experimental frequencies and intensities in an aqueous environment. Equilibrium bond polarizabilities were estimated from refractive index measurements in connection with Raman intensities of the v2 bending modes. The results are discussed in connection with the ionic size of the XO4− anions and behaviour of perrhenate and pertechnetate ions in extraction processes.
The transformation of τ‐particles into T4 heads. I. Evidence for the conservative mode of this transformation.
Authors: Bijlenga R. K. L. , v. d. Broek R. , Kellenberger E.
Published: May 2005

Asynchroneous T4 phage head maturation includes the step of P23 cleavage: P23 of head‐related τ‐particles is cleaved into P23

This paper is part of the thesis of R. K. L. Bijlenga. It is number X of the series: “Studies on the morphopoieses of the head of phage T‐even.”

of capsids with a conservative mode of transformation as evidenced by “heavy” labeling in temperature shift‐down experiments with mutant 24 (tsL90). Assuming a subunit pool, data indicate in situ cleavage on individual precursor particles. The interpretation becomes less interesting when assuming a compartmentation of the membrane surface; this hypothesis is not ruled out.