| 1. |
- Adcox, K, et al.
(författare)
-
PHENIX detector overview
- 2003
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
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| 3. |
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| 4. |
- 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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| 5. |
- Baum, C, et al.
(författare)
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Chance or necessity? Insertional mutagenesis in gene therapy and its consequences
- 2004
-
Ingår i: Molecular Therapy. - : Elsevier BV. - 1525-0024 .- 1525-0016. ; 9:1, s. 5-13
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Forskningsöversikt (refereegranskat)abstract
- Recently, unusual forms of leukemias have developed as complications following retroviral transfer of potentially therapeutic genes into hematopoietic cells. A crucial component in the pathogenesis of these complications was the upregulation of a cellular proto-oncogene by random insertion of the retroviral gene transfer vector. These findings have great implications for the genetic manipulation of somatic stem cells in medicine. This review discusses the extent to which the random oncogene activation may have required disease-specific stimuli of the transgene and the hematopoietic milieu to become leukemogenic. Based on these considerations, we propose approaches to risk prediction and prevention.
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| 6. |
- Bertini, L, et al.
(författare)
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Nanostructured Co1-xNixSb3 skutterudites : Synthesis, thermoelectric properties, and theoretical modeling
- 2003
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:1, s. 438-447
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Tidskriftsartikel (refereegranskat)abstract
- Nanostructured skutterudite Co1-xNixSb3 has been synthesized by chemical alloying with Ni substitution for Co up to 27.5 at. %. High concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric materials and could thus increase their thermoelectric dimensionless figure-of-merit ZT. Material preparation comprises two key stages, coprecipitation of the precursor, and thermal processing to produce the skutterudite. By modeling the chemistry of the metal ions in aqueous solution, optimum coprecipitation conditions were achieved. The precipitated precursor consists of a solid solution of the different intermediate compounds, and exhibits high reactivity. Calcination and reduction of the precursor resulted in the alloying of these elements and in the formation of skutterudite at a temperature as low as 723-773 K. Unfilled CoSb3 skutterudites were prepared by chemical precipitation from aqueous solutions to achieve powders with a very small grain size (similar to40 nm). Compacted samples were produced from this powder by uniaxial pressing under various conditions. Thermal conductivity, electrical resistivity and Seebeck coefficient of the resulting compacts were measured in a temperature range from 150 to 575 K. Measurement procedures were standardized for absolute accuracy and reproducibility between the DLR, Cologne and NEDO, Cardiff Laboratories. It was found that the thermal conductivity can be decreased by almost an order of magnitude at the highest concentration of grain boundaries compared to highly annealed CoSb3. Scanning Seebeck microthermoprobe examination, facilitated spatially resolved measurement of Seebeck coefficient S, providing information on samples' homogeneity and on its effect on local S. Indications on the formation of an additional Ni containing phase were found. The electronic structure of Ni-doped skutterudites has been investigated by means of fully periodic density functional theory calculations and a topological analysis of the resulting electron densities. Ni substitution for Co doubles the electronic charge transfer from the pnicogen ring to the metal frame and fills the region of the CoSb3 band gap with occupied states, thus explaining the increase of electrical conductivity observed experimentally. The effect of the Ni substitution on the thermal conductivity is analyzed. The computed changes of the cell parameter with rising Ni content differ with those found by x-ray powder diffraction, thereby suggesting that the structural hypothesis of Ni replacing Co in the cubic frame of the skutterudite is only approximate or possibly incorrect.
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| 7. |
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| 8. |
- Lewis, Cathryn M, et al.
(författare)
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Genome scan meta-analysis of schizophrenia and bipolar disorder, part II : Schizophrenia
- 2003
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Ingår i: American Journal of Human Genetics. - 0002-9297 .- 1537-6605. ; 73:1, s. 34-48
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Tidskriftsartikel (refereegranskat)abstract
- Schizophrenia is a common disorder with high heritability and a 10-fold increase in risk to siblings of probands. Replication has been inconsistent for reports of significant genetic linkage. To assess evidence for linkage across studies, rank-based genome scan meta-analysis (GSMA) was applied to data from 20 schizophrenia genome scans. Each marker for each scan was assigned to 1 of 120 30-cM bins, with the bins ranked by linkage scores (1 = most significant) and the ranks averaged across studies (R(avg)) and then weighted for sample size (N(sqrt)[affected casess]). A permutation test was used to compute the probability of observing, by chance, each bin's average rank (P(AvgRnk)) or of observing it for a bin with the same place (first, second, etc.) in the order of average ranks in each permutation (P(ord)). The GSMA produced significant genomewide evidence for linkage on chromosome 2q (PAvgRnk<.000417). Two aggregate criteria for linkage were also met (clusters of nominally significant P values that did not occur in 1,000 replicates of the entire data set with no linkage present): 12 consecutive bins with both P(AvgRnk) and P(ord)<.05, including regions of chromosomes 5q, 3p, 11q, 6p, 1q, 22q, 8p, 20q, and 14p, and 19 consecutive bins with P(ord)<.05, additionally including regions of chromosomes 16q, 18q, 10p, 15q, 6q, and 17q. There is greater consistency of linkage results across studies than has been previously recognized. The results suggest that some or all of these regions contain loci that increase susceptibility to schizophrenia in diverse populations.
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| 9. |
- Schmidt, M, et al.
(författare)
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Efficient characterization of retro-, lenti-, and foamyvector-transduced cell populations by high-accuracy insertion site sequencing
- 2003
-
Ingår i: Annals of the New York Academy of Sciences (HEMATOPOIETIC STEM CELLS 2002: GENETICS AND FUNCTION: Fourth International Symposium). - 0077-8923. ; 996, s. 112-121
-
Konferensbidrag (refereegranskat)abstract
- The identification of unknown genomic flanking DNA sequences can be used for the molecular monitoring of retro-, lenti- and foamyviral integration, transgenes in early embryogenesis, insertional mutagenesis, cell fate, and stem cell plasticity. Most existing methods reflect shortcomings in sensitivity and or specificity, thus limiting genomic sequencing of unknown flanking DNA to clonal preparations. The application of linear amplification-mediated PCR (LAM-PCR), a recently developed direct sequencing technique for flanking DNA, should circumvent current limitations in different research fields. This technique combines preamplification of target DNA with a unique succession of enzymatic reactions on solid-phase. Using LAM-PCR, we show the previously unfeasible in vivo retro-, lenti- and foamyvirus integration site analysis in primate peripheral blood hematopoietic cells and human xenograft hematopoiesis. In light of two severe adverse events that occurred in a clinical SCID-X1 gene therapy trial, in vivo monitoring of the reinfused transduced cell pool by integration site analysis will be an important component of each gene transfer and therapy study aimed at clinical use.
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| 10. |
- Toprak, Muhammet S., et al.
(författare)
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The impact of nanostructuring on the thermal conductivity of thermoelectric CoSb3
- 2004
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 14:12, s. 1189-1196
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Tidskriftsartikel (refereegranskat)abstract
- The high concentration of grain boundaries provided by nanostructuring is expected to lower the thermal conductivity of thermoelectric materials, which favors an increase in their thermoelectric figure-of-merit, ZT. A novel chemical alloying method has been used for the synthesis of nanoengineered-skutterudite CoSb3. The CoSb3 powders were annealed for different durations to obtain a set of samples with different particle sizes. The samples were then compacted into pellets by uniaxial pressing under various conditions and used for the thermoelectric characterization. The transport properties were investigated by measuring the Seebeck coefficient and the electrical and thermal conductivities in the temperature range 300 K to 650 K. A substantial reduction in the thermal conductivity of CoSb3 was observed with decreasing grain size in the nanometer region. For an average grain size of 140 nm, the thermal conductivity was reduced by almost an order of magnitude compared to that of a single crystalline or highly annealed polycrystalline material. The highest ZT value obtained was 0.17 at 611 K for a sample with an average grain size of 220 nm. The observed decrease in the thermal conductivity with decreasing grain size is quantified using a model that combines the macroscopic effective medium approaches with the concept of the Kapitza resistance. The compacted samples exhibit Kapitza resistances typical of semiconductors and comparable to those of Si-Ge alloys.
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| 11. |
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| 12. |
- Åkesson, Torsten, et al.
(författare)
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Aging studies for the ATLAS Transition Radiation Tracker (TRT)
- 2003
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 515:1-2, s. 166-179
-
Konferensbidrag (refereegranskat)abstract
- A summary of the aging and material validation studies carried out for the ATLAS Transition Radiation Tracker (TRT) is presented. Particular emphasis is put on the different phenomena observed in straw tubes operating with the chosen Xe/CF4/CO2 mixture. The most serious effects observed are silicon deposition on the anode wire and damage of the anode wire gold plating. Etching phenomena and active radical effects are also discussed. With a careful choice of all materials and components, and with good control of the water contamination in the active gas, the ATLAS TRT will operate reliably for 10 years at the LHC design luminosity. To demonstrate this fully, more work is still needed on the gas system purification elements, in particular to understand their interplay with the active species containing fluorine created in the avalanche process under irradiation.
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| 13. |
- Åkesson, Torsten, et al.
(författare)
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An X-ray scanner for wire chambers
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 507:3, s. 622-635
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Tidskriftsartikel (refereegranskat)abstract
- The techniques to measure the position of sense wires and field wires, the gas gain and the gas flow rate inside wire chambers using a collimated and filtered X-ray beam are reported. Specific examples are given using barrel modules of the Transition Radiation Tracker of the ATLAS experiment. (C) 2003 Elsevier B.V. All rights reserved.
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| 14. |
- Åkesson, Torsten, et al.
(författare)
-
ATLAS Transition Radiation Tracker test-beam results
- 2004
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002. ; 522:1-2, s. 50-55
-
Konferensbidrag (refereegranskat)abstract
- Several prototypes of the Transition Radiation Tracker for the ATLAS experiment at the LHC have been built and tested at the CERN SPS accelerator. Results from detailed studies of the straw-tube hit registration efficiency and drift-time measurements and of the pion and electron spectra without and with radiators are presented.
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| 15. |
- Åkesson, Torsten, et al.
(författare)
-
Status of design and construction of the Transition Radiation Tracker (TRT) for the ATLAS experiment at the LHC
- 2004
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:1-2, s. 131-145
-
Tidskriftsartikel (refereegranskat)abstract
- The ATLAS Inner Detector consists of three sub-systems, the Pixel Detector at the innermost radius, the Semi-Conductor Tracker at intermediate radii, and the Transition Radiation Tracker (TRT) at the outermost radius in front of the electromagnetic calorimeter. The TRT provides a combination of continuous tracking with many projective measurements based on individual drift-tubes (or straws) and of electron identification based on radiator fibres or foils interleaved between the straws themselves. This paper describes the current status of design and construction of the various components of the TRT: the assembly of the barrel modules has recently been completed, that of the end-cap wheels is well underway, and the on-detector front-end electronics is in production. The detector modules and front-end electronics boards will be integrated together over the next year, the barrel and end-cap TRT parts will be assembled and tested with their SCT counterparts during 2005 and installation and commissioning in the ATLAS pit will take place at the end of 2005 and the beginning of 2006. (C) 2004 Elsevier B.V. All rights reserved.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
- Engert, JC, et al.
(författare)
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5 ' flanking variants of resistin are associated with obesity
- 2002
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 51:5, s. 1629-1634
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Tidskriftsartikel (refereegranskat)abstract
- Diabetes and obesity have long been known to be related. The recently characterized adipocyte hormone resistin (also called FIZZ3/ADSF) has been implicated as a molecular link between impaired glucose tolerance (IGT) and obesity in mice. A search for sequence variants at the human resistin locus identified nine single-nucleotide polymorphisms (SNPs) but no coding variants. An investigation into the association of these SNPs with diabetes and obesity revealed two 5' flanking variants (g.-537 and g.-420), in strong linkage disequilibrium, that are associated with BMI. In nondiabetic individuals from the Quebec City area and the Saguenay-Lac-St-Jean region of Quebec, the g.-537 mutation (allelic frequency = 0.04) was significantly associated with an increase in BMI (P = 0.03 and P = 0.01, respectively). When the data from these two populations were combined and adjusted for age and sex, both the g.-537 (odds ratio [OR] 2.72, 95% Cl 1.28-5.81) and the g.-420 variants (1.58, 1.06-2.35) were associated with an increased risk for a BMI greater than or equal to30 kg/m(2). In contrast, in case/control and family-based study populations from Scandinavia, we saw no effect on BMI with either of these promoter variants. No association was seen with diabetes in any of the population samples.
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| 20. |
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| 21. |
- Flohr, C, et al.
(författare)
-
How atopic is atopic dermatitis?
- 2004
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Ingår i: The Journal of allergy and clinical immunology. - : Elsevier BV. - 0091-6749. ; 114:1, s. 150-158
-
Tidskriftsartikel (refereegranskat)
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| 22. |
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| 23. |
- Fodor, Gabor, et al.
(författare)
-
RSVP handling in 3G networks
- 2001
-
Patent (populärvet., debatt m.m.)abstract
- In a radio network, the implementation of IP signaling may be used to provide end-to-end Quality of Service. This may be accomplished by mapping corresponding parameters between the IP protocol and the radio network protocol in order to achieve the desired delay and bandwidth requirements. Various events in the state machines of the protocols may also be used to trigger interworking functions.
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| 24. |
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| 25. |
- Joss, D. T., et al.
(författare)
-
Identification of excited states in Os-167 and Os-168 : shape coexistence at extreme neutron deficiency
- 2001
-
Ingår i: Nuclear Physics A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 689:04-mar, s. 631-654
-
Tidskriftsartikel (refereegranskat)abstract
- Excited states in the very neutron-deficient isotopes Os-167 and Os-168 have been observed using the reaction Sn-112(Ni-58, 2pxn). The JUROSPHERE gamma -ray spectrometer array was used in conjunction with the RITU gas-filled recoil separator to collect prompt gamma radiation in coincidence with recoils implanted in a silicon strip detector located at the focal plane of RITU. Using a selective recoil decay tagging technique it has been possible to unambiguously assign gamma -ray transitions to Os-167 and Os-168 through the characteristic a radioactivity of these nuclides. The high-spin structure of the bands is discussed in terms of quasiparticle configurations within the framework of the cranked shell model. The role of shape coexistence in Os-168 is examined with phenomenological three-band mixing calculations.
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| 26. |
- Joss, D. T., et al.
(författare)
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Yrast spectroscopy in the neutron-deficient nucleus Os-169
- 2002
-
Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 66:5
-
Tidskriftsartikel (refereegranskat)abstract
- Excited states in the neutron-deficient isotope Os-169 have been identified for the first time in an experiment using the Jurosphere gamma-ray spectrometer in conjunction with the Ritu gas-filled recoil separator. The problems associated with identifying neutron-deficient isotopes produced with low fusion cross sections against a high background of competing channels, including fission, have been overcome by using the recoil-decay tagging technique. The band structures observed in Os-169 are interpreted in the context of the systematics of neighboring nuclei and the predictions of cranked Woods-Saxon calculations. The systematics of the second (i(13/2))(2) neutron alignment in this region are discussed.
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| 27. |
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| 28. |
- Karlsson, J, 1966-, et al.
(författare)
-
Sequencing of the Francisella tularensis strain Schu 4 genome reveals the shikimate and purine metabolic pathways, targets for the construction of a rationally attenuated auxotrophic vaccine.
- 2000
-
Ingår i: Microbial & Comparative Genomics. - : Mary Ann Liebert Inc. - 1090-6592 .- 2168-6637. ; 5:1, s. 25-39
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Tidskriftsartikel (refereegranskat)abstract
- Francisella tularensis is the etiological agent of tularemia, a serious disease in several Northern hemisphere countries. The organism has fastidious growth requirements and is very poorly understood at the genetic and molecular levels. Given the lack of data on this organism, we undertook the sample sequencing of its genome. A random library of DNA fragments from a highly virulent strain (Schu 4) of F. tularensis was constructed and the nucleotide sequences of 13,904 cloned fragments were determined and assembled into 353 contigs. A total of 1.83 Mb of nucleotide sequence was obtained that had a G+C content of 33.2%. Genes located on plasmids pOM1 and pNFL10, which had been previously isolated from low virulence strains of F. tularensis, were absent but all of the other known F. tularensis genes were represented in the assembled data. F. tularensis Schu4 was able to grow in the absence of aromatic amino acids and orthologues of genes which could encode enzymes in the shikimate pathway in other bacteria were identified in the assembled data. Genes that could encode all of the enzymes in the purine biosynthetic and most of the en- zymes in the purine salvage pathways were also identified. This data will be used to develop defined rationally attenuated mutants of F. tularensis, which could be used as replacements for the existing genetically undefined live vaccine strain.
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| 29. |
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| 30. |
- Ling, G., et al.
(författare)
-
PATCHED and p53 gene alterations in sporadic and hereditary basal cell cancer
- 2001
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Ingår i: Oncogene. - : Springer. - 0950-9232 .- 1476-5594. ; 20:53, s. 7770-7778
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Tidskriftsartikel (refereegranskat)abstract
- It is widely accepted that disruption of the hedgehog-patched pathway is a key event in development of basal cell cancer. In addition to patched gene alterations, p53 gene mutations are also frequent in basal cell cancer. We determined loss of heterozygosity in the patched and p53 loci as well as sequencing the p53 gene in tumors both from sporadic and hereditary cases. A total of 70 microdissected samples from tumor and adjacent skin were subjected to PCR followed by fragment analysis and DNA sequencing. We found allelic loss in the patched locus in 6/8 sporadic basal cell cancer and 17/19 hereditary tumors. All sporadic and 7/20 hereditary tumors showed p53 gene mutations. Loss of heterozygosity in the p53 locus was rare in both groups. The p53 mutations detected in hereditary tumors included rare single nucleotide deletions and unusual double-base substitutions compared to the typical ultraviolet light induced missense mutations found in sporadic tumors. Careful microdissection of individual tumors revealed genetically linked subclones with different p53 and/or patched genotype providing an insight on time sequence of genetic events. The high frequency and co-existence of genetic alterations in the patched and p53 genes suggest that both these genes are important in the development of basal cell cancer.
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| 31. |
- Liu, Jian, et al.
(författare)
-
Toxicity of familial ALS-linked SOD1 mutants from selective recruitment to spinal mitochondria
- 2004
-
Ingår i: Neuron. - : Cell Press. - 0896-6273 .- 1097-4199. ; 43:1, s. 5-17
-
Tidskriftsartikel (refereegranskat)abstract
- One cause of amyotrophic lateral sclerosis (ALS) is mutation in ubiquitously expressed copper/zinc superoxide dismutase (SOD1), but the mechanism of toxicity to motor neurons is unknown. Multiple disease-causing mutants, but not wild-type SOD1, are now demonstrated to be recruited to mitochondria, but only in affected tissues. This is independent of the copper chaperone for SOD1 and dismutase activity. Highly preferential association with spinal cord mitochondria is seen in human ALS for a mutant SOD1 that accumulates only to trace cytoplasmic levels. Despite variable proportions that are successfully imported, nearly constant amounts of SOD1 mutants and covalently damaged adducts of them accumulate as apparent import intermediates and/or are tightly aggregated or crosslinked onto integral membrane components on the cytoplasmic face of those mitochondria. These findings implicate damage from action of spinal cord-specific factors that recruit mutant SOD1 to spinal mitochondria as the basis for their selective toxicity in ALS.
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| 32. |
- Loren, Niklas, et al.
(författare)
-
Phase separation induced by conformational ordering of gelatin in gelatin/maltodextrin mixtures
- 2001
-
Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 34:2, s. 289-297
-
Tidskriftsartikel (refereegranskat)abstract
- Mixtures of gelatin and maltodextrin in aqueous solution have been quenched to temperatures at which they are initially miscible but where gelatin ordering is initiated. In many cases phase separation was observed to occur after a significant time delay, and the dependence of these delays on quench temperature and biopolymer concentration has been studied in detail using turbidity measurements and confocal laser scanning microscopy (CLSM). Furthermore, by observing the optical rotation (OR) and turbidity of the system simultaneously, the gelatin helix content and the time delay before the onset of phase separation were monitored concurrently. The observed delay times were found to correspond to the time taken for the development of a certain degree of gelatin ordering, which drives the separation process. A further consequence of gelatin ordering is the viscosifying of the solution and, at sufficient concentrations, the formation of a gel. Therefore, rheological measurements have been used in addition to turbidity measurements and CLSM in order to monitor further the structural development of the systems. A comparison of the data obtained from these techniques shows that while the development of a certain elasticity will trap the system morphology, this elasticity is not directly related to that found at the gel point. At low maltodextrin concentrations, where phase separation was not detected by turbidity, transmission electron microscopy (TEM) has been used to examine the microstructure on a smaller length scale.
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| 33. |
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| 34. |
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| 35. |
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| 36. |
- Persson, A. E., et al.
(författare)
-
Analysis of p53 mutations in single cells obtained from histological tissue sections
- 2000
-
Ingår i: Analytical Biochemistry. - : Elsevier BV. - 0003-2697 .- 1096-0309. ; 287:1, s. 25-31
-
Tidskriftsartikel (refereegranskat)abstract
- We have previously reported on direct sequence analysis of the p53 gene in laser-dissected single cells from tissue sections, where each allele of two fragments (exons 7 and 8) could be accurately analyzed in only 14% of the cells due to the high frequency of exon and allele dropout. Here in an effort to minimize this problem, we have investigated various approaches for sample preparation and gene amplification. By pinpointing some critical steps in the procedure, we could increase the number of investigated exons and substantially improve the genetic analysis of single cells obtained from histochemically stained frozen tissue sections. The biggest improvement was achieved by minimizing DNA degradation using EDTA as a nuclease inhibitor in all sample preparation steps. Efforts to increase primer annealing, by increasing the concentration of template and primers, in addition to prolonging the annealing and extension times, also improved the amplification efficiency. With these measures we can now amplify six individual exons of the p53 gene (exons 4-9) in 70% of the cells and in 50% of these cells both alleles are amplified. This allows application of the method in various investigations such as within the held of tumor pathology.
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| 37. |
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| 38. |
- Siciliano, C., et al.
(författare)
-
Intelligibility of an ASR-controlled synthetic talking face
- 2004
-
Ingår i: Journal of the Acoustical Society of America. - 0001-4966 .- 1520-8524. ; 115:5, s. 2428-
-
Tidskriftsartikel (refereegranskat)abstract
- The goal of the SYNFACE project is to develop a multilingual synthetic talking face, driven by an automatic speech recognizer (ASR), to assist hearing‐impaired people with telephone communication. Previous multilingual experiments with the synthetic face have shown that time‐aligned synthesized visual face movements can enhance speech intelligibility in normal‐hearing and hearing‐impaired users [C. Siciliano et al., Proc. Int. Cong. Phon. Sci. (2003)]. Similar experiments are in progress to examine whether the synthetic face remains intelligible when driven by ASR output. The recognizer produces phonetic output in real time, in order to drive the synthetic face while maintaining normal dialogue turn‐taking. Acoustic modeling was performed with a neural network, while an HMM was used for decoding. The recognizer was trained on the SpeechDAT telephone speech corpus. Preliminary results suggest that the currently achieved recognition performance of around 60% frames correct limits the usefulness of the synthetic face movements. This is particularly true for consonants, where correct place of articulation is especially important for visual intelligibility. Errors in the alignment of phone boundaries representative of those arising in the ASR output were also shown to decrease audio‐visual intelligibility.
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| 39. |
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| 40. |
- Williams, Amanda M, et al.
(författare)
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Intestinal alpha beta T cells differentiate and rearrange antigen receptor genes in situ in the human infant.
- 2004
-
Ingår i: Journal of immunology (Baltimore, Md. : 1950). - 0022-1767. ; 173:12, s. 7190-9
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Tidskriftsartikel (refereegranskat)abstract
- Intestinal Ag exposure during neonatal life influences appropriate adult immune responses. To define the mechanisms shaping the T cell repertoire during this period, we examined T cell differentiation and receptor diversity in the intestine of human infants. Developmental phenotypes of intraepithelial and lamina propria intestinal T cells from infants aged 1 day to 2 years were assessed ex vivo by flow cytometry and in situ by triple-fluorescent immunohistochemistry. Gene recombination-specific enzymes were assessed by PCR. TCR beta-chain V region gene diversity was determined by sequencing. Several different early lineage T cell populations were present neonatally: CD3(+)4(-)8(-) T cells were present at birth and numbers decreased during the neonatal period; CD3(+)4(+)8(+) T cells were present in low numbers throughout infancy; and CD3(+)4(+)8(-) or CD3(+)4(-)8(+) T cells increased with age. Very early lineage T cells, CD3(-)2(-)7(+) and CD3(-)2(+)7(+), were present neonatally, but were essentially absent at 1 year. Most lamina propria T cells differentiated rapidly after birth, but maturation of intraepithelial T cells took place over 1 year. Intestinal samples from infants less than 6 mo old contained transcripts of T early alpha and TdT, and 15 of 19 infant samples contained mRNA for RAG-1, some coexpressing RAG-2. TCR beta-chain repertoires were polyclonal in infants. Immature T cells, pre-T cells, and genes involved in T cell recombination were found in the intestine during infancy. T cell differentiation occurs within the neonatal human intestine, and the TCR repertoire of these developing immature T cells is likely to be influenced by luminal Ags. Thus, mucosal T cell responsiveness to environmental Ag is shaped in situ during early life.
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| 41. |
- Williams, C K, et al.
(författare)
-
The collapse of cycles in the dynamics of North American grouse populations
- 2004
-
Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 7:12, s. 1135-1142
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Tidskriftsartikel (refereegranskat)abstract
- Cyclic dynamics of bird and mammal populations are commonly reported in northern latitudes throughout the world, and recent European observations on rodents and grouse suggest that cycle periods decline towards southern latitudes. To investigate latitudinal patterns of cyclic dynamics in North America, we assembled 27 long-term data sets collected between 1939 and 2001 for three grouse species. By fitting the data with autoregressive models to measure direct and delayed density dependence, we show that, in contrast to European studies, North American grouse exhibit period increases from north to south, with cycles collapsing via period lengthening. This occurs because delayed density dependence decreases in southern latitudes, whereas direct density dependence increases. These results show that cyclic dynamics can dissipate by period lengthening as well as the period shortening postulated for European grouse and rodents.
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| 42. |
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| 43. |
- Williams, M.A.K., et al.
(författare)
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Kinetics of droplet growth in gelatin/maltodextrin mixtures following thermal quenching
- 2001
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 17:11, s. 3412-3418
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Tidskriftsartikel (refereegranskat)abstract
- Rates of droplet growth, following the thermal quenching of gelatin/maltodextrin mixtures into the incompatible region of the phase diagram, have been obtained from turbidity measurements. The results from experiments carried out at temperatures that prohibit the involvement of biopolymer conformational ordering and gelation are in good agreement with those obtained by similar studies of binary synthetic polymer systems and with theoretical predictions. For mixtures that would phase separate at temperatures above the gelatin ordering temperature (T0) but which are quenched directly to temperatures below this, droplet growth shows modified kinetics owing primarily to restrictions imposed by the viscosifying continuous phase. However, for a mixture that was initially observed to be miscible following quenches to temperatures below T0, it is proposed that biopolymer ordering induces phase separation, which was found to occur after significant delay periods.
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| 44. |
- Åkesson, Torsten, et al.
(författare)
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Tracking performance of the transition radiation tracker prototype for the ATLAS experiment
- 2002
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 485:3, s. 298-310
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Tidskriftsartikel (refereegranskat)abstract
- A prototype of the Transition Radiation Tracker (TRT) for the ATLAS experiment at the CERN LHC has been built and tested at the CERN SPS. Detailed studies of the drift-time measurements, alignment technique, hit registration efficiency, track and momentum accuracy were performed. A coordinate measurement accuracy of 150 Pin for a single TRT drift tube and momentum resolution of 0.8% for 20 GeV pions in a 1.56 T magnetic field were achieved. The results obtained are in agreement with the expected tracking performance of the ATLAS TRT. (C) 2001 Published by Elsevier Science B.V.
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