| 1. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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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. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 2. |
- Williams, N M, et al.
(författare)
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A systematic genomewide linkage study in 353 sib pairs with schizophrenia.
- 2003
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 73:6, s. 1355-1367
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Tidskriftsartikel (refereegranskat)abstract
- We undertook a genomewide linkage study in a total of 353 affected sib pairs (ASPs) with schizophrenia. Our sample consisted of 179 ASPs from the United Kingdom, 134 from Sweden, and 40 from the United States. We typed 372 microsatellite markers at approximately 10-cM intervals. Our strongest finding was a LOD score of 3.87 on chromosome 10q25.3-q26.3, with positive results being contributed by all three samples and a LOD-1 interval of 15 cM. This finding achieved genomewide significance (P<.05), on the basis of simulation studies. We also found two regions, 17p11.2-q25.1 (maximum LOD score [MLS] = 3.35) and 22q11 (MLS = 2.29), in which the evidence for linkage was highly suggestive. Linkage to all of these regions has been supported by other studies. Moreover, we found strong evidence for linkage (genomewide P<.02) to 17p11.2-q25.1 in a single pedigree with schizophrenia. In our view, the evidence is now sufficiently compelling to undertake detailed mapping studies of these three regions.
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| 3. |
- Kjellson, Fred, et al.
(författare)
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Bone cement X-ray contrast media: A clinically relevant method of measuring their efficacy.
- 2004
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Ingår i: Journal of Biomedical Materials Research. Part B - Applied Biomaterials. - : Wiley. - 1552-4981 .- 1552-4973. ; 70B:2, s. 354-361
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Tidskriftsartikel (refereegranskat)abstract
- It is important to compare different contrast media used in bone cement according to their ability to attenuate X-rays and thereby produce image contrast between bone cement and its surroundings in clinical applications. The radiopacity of bone cement is often evaluated by making radiographs of cement in air at an X-ray tube voltage of 40 kV. We have developed a method for ranking contrast media in bone cement simulating the clinical situation, by (1) choosing the same X-ray tube voltage as used in clinical work, and (2) using a water phantom to imitate the effects of the patients' soft tissue on the X-ray photons. In clinical work it is desirable to have low radiation dose, but high image contrast. The voltage chosen is a compromise, because both dose and image contrast decrease with higher voltage. Three contrast media (ZrO2, BaSO4, and Iodixanol) have been compared for degree of "image contrast." Comparing 10 wt % contrast media samples at an X-ray tube voltage of 40 kV, ZrO2 produced higher image contrast than the other media. However, at 80 kV, using a water phantom, the results were reversed, ZrO2 produced lower image contrast than both BaSO4 and Iodixanol. We conclude that evaluations of contrast media should be made with voltages and phantoms imitating the clinical application. (C) 2004 Wiley Periodicals, Inc.
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| 4. |
- Nilsson, Malin K, et al.
(författare)
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The Effect of Aging an Injectable Bone Graft Substitute in Simulated Body Fluid
- 2003
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Ingår i: Bioceramics 15 (Key Engineering Materials). - 0878499113 ; 240-242, s. 403-406
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Konferensbidrag (refereegranskat)abstract
- This study shows how porosity is obtained in a biphasic injectable bone graft when aging it in SBF. The injectable bone consists of apatite and calcium sulphate and the porosity is developed by dissolution of the latter material. It was shown that the dissolution was constant with time. Porosity was formed both on the surface and in the bulk of the material. The maximum compressive strength (29 MPa) was obtained after 14 days in SBF. It then decreased as the porosity increased in the material. Chemical characterization was performed by X-ray diffraction and evaluation of the microstructure was performed by Scanning Electron Microcopy.
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| 5. |
- Persson, Johan K, et al.
(författare)
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Ultrasound nucleolysis: an in vitro study.
- 2002
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Ingår i: Ultrasound in Medicine and Biology. - 0301-5629. ; 28:9, s. 1189-1197
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Tidskriftsartikel (refereegranskat)abstract
- Thermal intradiscal therapy for chronic low back pain, using a catheter inserted into the intervertebral disc, is becoming more popular in the treatment of low back pain. The aim of this study was to investigate the possibility of heating the nucleus pulposus of the intervertebral disc with high-intensity focused ultrasound (US) or HIFU. Two specific situations were considered, invasive transducers that would be in contact with the annulus fibrosus of the disc, and noninvasive transducers that could be used externally. Theoretical simulations were performed to find the optimal parameters of US transducers and then experimental studies were done using transducers made to these specifications. These experiments confirmed that it was possible to heat the discs with HIFU. Two orthogonal transducers resulted in a superior temperature distribution than using just one transducer. It is, therefore, feasible to consider thermal treatment of the nucleus pulposus of the disc using noninvasive US. (E-mail: Johan.Persson@ort.lu.se)
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| 6. |
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