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  • 1
    Electronic Resource
    Electronic Resource
    Effect of Enzyme Hydration on the Catalytic Activity of Chymotrypsin in Nearly Anhydrous Organic Suspensions (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 672 (1992), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Notes: The relationship between enzyme hydration and the catalytic activity of chymo-trypsin powders suspended in nearly anhydrous 1 M n-propanol/toluene solutions has been studied. The enzyme hydration range examined extends from approximately 2 to 10 wt% water sorbed. Measurements of apparent enzyme activity and the number of active sites as a function of enzyme hydration were used to calculate intrinsic enzyme activity as a function of enzyme hydration. It was found that the apparent enzyme activity increased linearly over this hydration range and that approximately 30% of the enzyme was catalytically active independent of the hydration level. Thus, the observed increase in apparent catalytic activity with increasing enzyme hydration results from an increase in the catalytic efficiency of a fixed number of active sites, rather than an increase in the population of active sites. Inhibitor binding in the organic suspension was also measured using the transition state analogue, (R)-1-acetamido-2-phenylethane boronic acid, which binds reversibly to the active site of the enzyme. The inhibition results suggest that one role of water in activating nearly dry enzyme suspensions is to enhance the intrinsic catalytic activity through transition state stabilization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1992.tb35635.x
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  • 2
    Electronic Resource
    Electronic Resource
    Biphasic Effect of Cell Surface Sialic Acids on Pancreatic Cancer Cell Adhesiveness
    Amsterdam : Elsevier
    Biochemical and Biophysical Research Communications 195 (1993), S. 1096-1103 
    Details
    ISSN: 0006-291X
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1006/bbrc.1993.2157
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  • 3
    Electronic Resource
    Electronic Resource
    A new thermal emission cesium primary ion source for secondary ion mass spectrometer : Proceedings of the fourth International Conference on Ion Sources (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 2414-2416 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A thermal emission cesium primary ion source for investigation of solid-state surface layers by the SIMS method is described. The characteristics of the constructed ion source are presented. The optimal values of accelerating, focusing, and stopping potentials for the primary ions focusing system are found (Va = 4500 V, Vf = 2500 V, and Vs = 2560 V, respectively). This thermal emission cesium primary ion source is used in the secondary ion mass spectrometer constructed at the Institute of Physics of the M. Curie-Skl(Slashthrough accent mark)odowska University in Lublin. To illustrate the application of the described ion source, the mass spectrum of GaAs secondary ions and the concentration profile of indium implanted into stainless steel at an energy of 150 keV and dose 5×1016 ions/cm2 are presented. The maximum concentration of In is at about 240-A(ring) depth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142947
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  • 4
    Electronic Resource
    Electronic Resource
    Spatially resolved electron temperature measurements with a microfabricated retarding field analyzer (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 932-934 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron temperature (Te) is an important parameter to quantify in the high-density plasmas commonly used in semiconductor manufacturing. Te is characteristic of the electron energy distribution which determines the plasma density and distribution of neutral and ionic species. Through application of theoretical considerations for the presheath and sheath, Te can be estimated from the ion energy distribution to a floating substrate. Utilizing microfabricated retarding field analyzers (RFAs) to measure the local ion energy distribution to a floating surface, spatially resolved Te measurements in an inductively coupled argon plasma have been made. Quantitative agreement between the RFA and Langmuir probe Te measurements was observed and the RFA Te measurements display the expected power, pressure, and spatial dependencies. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1448170
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  • 5
    Electronic Resource
    Electronic Resource
    039
Determination of Burn Depth using near Infrared Spectroscopy (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd/Inc.
    Wound repair and regeneration 12 (2004), S. 0 
    Details
    ISSN: 1524-475X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Burn depth, based on the hemodynamic alterations that occur following a thermal insult, can be assessed in a rapid, non-invasive, and nondestructive fashion using near infrared (NIR) spectroscopy. NIR has the capability to determine the difference between superficial and full thickness burn injuries. Methods: Sixteen burn patients admitted to an adult regional burn center were studied and evaluated with the NIR point and imaging devices. Non-burned skin adjacent to the burn site was used as the control. NIR measurements were compared between superficial (8 wounds), full thickness (8 wounds) burn wounds and control sites. Results: NIR was able to easily detect an increase in oxyhemoglobin (68.3%, p 〈 0.05), oxygen saturation (4.8%, p 〈 0.05%) and total hemoglobin (91.3%, p 〈 0.05) which typically occurs with superficial burn injuries. Full thickness injuries experienced a substantial drop in oxyhemoglobin (88.8%, p 〈 0.05), oxygen saturation (79.1%, p 〈 0.05) and total hemoglobin (77.5%, p 〈 0.05) in comparison to control sites. Conclusions: These results confirm that NIR spectroscopy can successfully distinguish between superficial and full thickness burn injuries. The second phase of this study will involve determining the depth of indeterminant burn wounds and this preliminary data will also be presented. Acknowledgement: National Research Council of Canada
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1067-1927.2004.0abstractal.x
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  • 6
    Electronic Resource
    Electronic Resource
    Cervical ripening with dehydroepiandrosterone sulphate (1982)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 89 (1982), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary. Dehydroepiandrosterone sulphate (DHEA-S) was given intravenously twice a week after 38 weeks gestation to ripen the uterine cervix in 20 nulliparae and 24 parous women who subsequently went into labour at term. The condition of the uterine cervix was assessed by Bishop scoring. The increase in the score in nulliparous women given DHEA-S was significantly greater than that in the control group, who were given placebo injections, on the 7th, 14th and 21st days. The increase in the parous women was significant only on the 7th day. In nulliparous women the dilatation, effacement and consistency improved significantly, while in the parous women the effect of DHEA-S was apparent only in the consistency. The duration of labour was significantly shortened by treatment with DHEA-S in nulliparae but this effect was not found in parous women. The interval between the first administration of DHEA-S and the onset of labour in nulliparae was significantly shorter than that in the control group. There were no serious side effects or complications. Our results suggest that DHEA-S may be used safely and effectively to ripen the uterine cervix and to trigger the onset of labour in late pregnancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1982.tb03612.x
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  • 7
    Electronic Resource
    Electronic Resource
    The influence of radiation damage on the sputtering yield of silicon
    Amsterdam : Elsevier
    Nuclear Instruments and Methods In Physics Research 209-210 (1983), S. 483-486 
    Details
    ISSN: 0167-5087
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-5087(83)90842-6
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  • 8
    Electronic Resource
    Electronic Resource
    Selective upregulation of a single distinctly structured var gene in chondroitin sulphate A-adhering Plasmodium falciparum involved in pregnancy-associated malaria (2003)
    Oxford, UK : Blackwell Science Ltd
    Molecular microbiology 49 (2003), S. 0 
    Details
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: Cytoadhesion of infected red blood cells (iRBC) is mediated through parasite-encoded, clonally variant surface antigens (VSA) and is a central process in the pathogenesis of Plasmodium falciparum malaria. Pregnancy-associated malaria (PAM) has been linked to VSA-mediated adhesion of iRBC to the glycosaminoglycan chondroitin sulphate A (CSA) in the placental intervillous space. Several studies have pointed to members of the PfEMP1 VSA family as mediators of CSA-specific iRBC sequestration in the placenta. Here, we report marked upregulation of a single var gene in several P. falciparum parasite isolates after selection for adhesion to CSA in vitro. The gene belongs to a highly conserved and common var gene subfamily (var2csa). The var2csa genes are structurally distinct from all other var genes in the parasite genome in lacking both CIDR and DBL-γ domains. These domains have previously been implicated in PfEMP1-mediated adhesion to CD36 and CSA. We also show that var2csa was transcribed at higher levels in three placental parasite isolates compared with transcription in parasites from peripheral blood of two children with P. falciparum malaria. This var gene thus has the properties expected of a gene encoding the parasite adhesion molecule that initiates the pathology associated with PAM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2958.2003.03570.x
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  • 9
    Electronic Resource
    Electronic Resource
    FT-IR photoacoustic depth profiling spectroscopy of enamel (1994)
    Springer
    Calcified tissue international 54 (1994), S. 481-485 
    Details
    ISSN: 1432-0827
    Keywords: Fourier transform infrared spectroscopy ; Photoacoustic spectroscopy ; Depth profile ; Enamel ; Carbonate ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Photoacoustic Fourier transform infrared (PA-FT-IR) depth profiling spectra of the enamel of an intact human tooth are obtained in a completely nondestructive fashion. The compositional and structural changes in the tissue are probed from the enamel surface to a depth of about 200 μm. These changes reflect the state of tissue development. The subsurface carbonate gradient in the enamel could be observed over the range of about 10–100 μm. The carbonate-to-phosphate ratio increases in the depth profile. The depth profile also reveals changes in the substitutional distribution of carbonate ions. Type A carbonates (hydroxyl substituted) increase relative to type B carbonates (phosphate substituted) with increasing thermal diffusion length. In addition to the changes in the carbonate ion distribution and content, the PA-FT-IR depth profile clearly indicates a dramatic increase in the protein content relative to the phosphate content with increased depth. The changes in the carbonate content and distribution, along with the changes in the protein content, may be responsible for the changes observed in the apatitic structure in the depth profile of the enamel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334328
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  • 10
    Electronic Resource
    Electronic Resource
    The hydration of proteins in nearly anhydrous organic solvent suspensions (1993)
    New York : Wiley-Blackwell
    Biopolymers 33 (1993), S. 1213-1224 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water sorption isotherms at 27°C have been measured for lysozyme and chymotrypsin in suspensions of toluene, di(n-butyl) ether, n-propanol, and a solution of 1M n-propanol in benzene. Sorption isotherms for the different suspensions are compared by converting solvent water content to the thermodynamic activity of water in each solvent. The sorption behavior is also compared to that for the two proteins hydrated from the vapor phase. At low water activities, all sorption isotherms are similar when compared on the basis of water activity. However, at higher activities, water sorption by the proteins in the organic suspensions is suppressed relative to the sorption of water vapor. The greatest suppression is observed for n -propanol, which suggests that the suppression may be due to a competition for water-binding sites on the protein by the organic solvent. Sorption isotherms at low water activities have also been predicted using a thermodynamic model in which it is assumed that water binds selectively to the ionizable residues on the surface of the protein. A comparison of predicted and measured sorption isotherms shows that the model can provide reasonable estimates of water sorption in nonpolar or moderately polar organic solvent suspensions at low levels of hydration. © 1993 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360330808
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