bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractA 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

AbstractTitanium (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

AbstractEpithelial (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

AbstractIsocitrate 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

AbstractThe 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

AbstractSeveral 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

AbstractThe 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

AbstractChildren 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

AbstractIn 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

AbstractThe 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

AbstractCapillary 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

AbstractA 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

AbstractConventional 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

AbstractTrace 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

AbstractAn 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

AbstractMethyl‐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

AbstractReaction 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

AbstractA 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

AbstractThree 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

AbstractA 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

AbstractMethods 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

AbstractThe 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

AbstractRecently 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.