| 1. |
- Andersson, Mikael, et al.
(författare)
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Characterization of the Chemical and Functional Stability of DEAE Sepharose Fast Flow
- 1993
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Ingår i: Process Biochemistry. - 1359-5113 .- 1873-3298. ; 28:4, s. 223-230
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Tidskriftsartikel (refereegranskat)abstract
- The release of amines from the ion-exchange groups in DEAE Sepharose® Fast Flow has been studied under static and column conditions. The leakage compounds have been identified and quantified by gas chromatography—mass spectrometry. It was shown that the main leakage product under acidic (pH 1) and basic conditions (pH 14) was N,N,N′,N′-tetraethylethylenediamine. Three other amines were also identified, namely N,N,N′-triethylethylenediamine, diethylaminoethanol and diethylamine. The leakage of amines from DEAE Sepharose Fast Flow treated at pH 1 or 14 for 672 h at 40°C corresponds to a reduction of only 1% of the total ion-exchange capacity.The functional stability of DEAE Sepharose Fast Flow was also studied by separation of a protein mixture during repeated cleaning-in-place treatments with 0·10 m HCl or 1·0 m NaOH. The separation behaviour was unaltered after the gel had been treated for a total contact time of 672 h with 0·10 m HCl or 1·0 m NaOH.The clearance of ethanol from a DEAE Sepharose Fast Flow column stored in a 20% ethanol aqueous solution was also studied.
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| 2. |
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| 3. |
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| 4. |
- Andersson, Åke, et al.
(författare)
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The MAX II synchrotron radiation storage ring
- 1994
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 343:2-3, s. 644-649
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Tidskriftsartikel (refereegranskat)abstract
- A 1.5 GeV third generation storage ring optimised for the VUV and soft X-ray spectral region is currently being built at MAX-lab. The magnet lattice, ring architecture and production choices are optimised to fit within rather tight boundary conditions without sacrificing performance. In this paper, the magnet lattice, light characteristics, injection and technical solutions for the ring are presented.
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| 5. |
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| 6. |
- Chaga, Grigoriy, et al.
(författare)
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Engineering of a metal coordinating site into human glutathione transferase M1-1 based on immobilized metal ion affinity chromatography of homologous rat enzymes
- 1994
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Ingår i: Protein Engineering. - : Oxford University Press (OUP). - 0269-2139 .- 1460-213X. ; 7:9, s. 1115-1119
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Tidskriftsartikel (refereegranskat)abstract
- Rat glutathione transferase (GST) 3-3 binds to Ni(II)-iminodiacetic acid (IDA)-agarose, whereas other GSTs that are abundant in rat liver do not bind to this immobilized metal ion affinity chromatography (IMAC) adsorbent. Rat GST 3-3 contains two superficially located amino acid residues, His84 and His85, that are suitably positioned for coordination to Ni(II)-IDA-agarose. This particular structural motif is lacking in GSTs that do not bind to the IMAC matrix. Creation of an equivalent His-His structure in the homologous human GST M1-1 by protein engineering afforded a mutant enzyme that displays affinity for Ni(II)-IDA-agarose, in contrast to the wild-type GST M1-1. The results identify a distinct site that is operational in IMAC and suggest an approach to the rational design of novel integral metal coordination sites in proteins.
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| 7. |
- Jonsson, Erland, 1946, et al.
(författare)
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A practical dependability measure for degradable computer systems with non-exponential degradation
- 1994
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Ingår i: IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processe - SAFEPROCESS 1994. ; Vol. 1, s. 231-237
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a vectorized measure for a set of behavioural dependability attributes. The measure is based on Markov processes and is intended for practical dependability trade-offs. It describes the system performance on a number of service levels. Thus, it is possible to merge attributes such as reliability, safety and performability into one single quality. Whereas reliability describes the functional fulfillment of a system, performability reflects its ability of functional degradation. The safety attribute handles a class of failures with catastrophic consequences and can be accommodated by means of introducing two or more service levels for a failed system.Many systems exhibit time-dependent degradation rates and non–exponential lifetimes. This situation can be handled by means of applying phase–type assumptions and introducing some additional states to the system, which would allow us to remain within the universe of Markov modelling.
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| 8. |
- Kirkhorn, Tomas, et al.
(författare)
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Demonstration of digital radiographs by means of ink jet-printed paper copies : Pilot study
- 1992
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Ingår i: Journal of Digital Imaging. - 0897-1889. ; 5:4, s. 246-251
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Tidskriftsartikel (refereegranskat)abstract
- Different digital medical images have been printed on paper with a continuous ink jet printer, and the quality has been evaluated. The emphasis has been on digital chest radiographs from a computed radiography system. The ink jet printing technique is described as well as the handling of the image data from image source to printer. Different versions of paper prints and viewing conditions were compared to find the optimum alternative. The evaluation has been performed to maximize the quality of the paper images to make them conform with the corresponding film prints and monitor images as much as possible. The continuous ink jet technique offers high-quality prints on paper at a considerably lower cost per copy compared with the cost of a film print. With a future switch-over from diagnosing of digital images on film to diagnosing them on monitors, hard copies for demonstration purposes will occasionally be needed. This need can be filled by ink jetprinted paper copies.
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| 9. |
- Lyttkens, Kerstin, et al.
(författare)
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Evaluation of the image quality of ink-jet printed paper copies of digital chest radiographs as compared with film : A receiver operating characteristic study
- 1994
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Ingår i: Journal of Digital Imaging. - 0897-1889. ; 7:2, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Paper copies of digital radiographs printed with the continuous ink-jet technique have proved to be of a high enough quality for demonstration purposes. We present a study on the image quality of ink-jet printed paper copies of digital chest radiographs, based on receiver operating characteristic (ROC) analysis. Eighty-three digital radiographs of a chest phatom with simulated tumors in the mediastinum and right lund, derived from a computed radiography (CR) system were presented in two series of hard copies as ink-jet printed paper copies and as laser recorded film. The images, with a matrix of 1,760×2,140 pixels, were printed with a spatial resolution of 10 pixels/mm in the CR film recorder as well as in the ink-jet printer. On film, every image was recorded in two versions, one optimized for the mediastinum and one for the lungs. On paper, only one image was printed; this constituted an effort to optimize both the mediastinum and the lungs. The ink-jet printed images, printed on a matt coated paper, were viewed as on-sight images with reflected light. The exdaminations were reviewed by six radiologists, and ROC curves were constructed. No significant difference was found between the performance of film and that of ink-jet paper prints. Because the cost for a paper copy is only a tenth of that of film, remarkable cost reductions can be achieved by using the ink jet technique instead. Our results show that further quality studies of ink-jet printed images are worthwhile.
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