| 61. |
- Drake, James Robert, et al.
(författare)
-
Reversed-Field Pinch Contributions to Resistive Wall Mode Physics and Control
- 2008
-
Konferensbidrag (refereegranskat)abstract
- Optimal feedback control of resistive-wall modes (RWM) is of common interest for toroidal fusionconcepts that use conducting walls for stabilization of ideal MHD modes. From the RWM control point of view,the RFP situation is in many respects similar to the advanced tokamak situation in the presence of very lowplasma rotation, where the most effective stabilizing mechanism is the feedback action of a set of active coils.Results from EXTRAP T2R (Sweden) and RFX-mod (Italy) RFP experiments have shown that full feedbackcontrol of multiple RWMs is possible and their deleterious effects can be completely suppressed. However it isnow important to optimize the RWM control systems both for the RFP and tokamak configuration for futureimplementation. Important aspects of optimization are effective mode identification and tracking capability,avoidance of the harmful effects of sideband modes (aliasing) in the control spectrum, minimized powerrequirements and robust controller stability. The paper describes collaborative work carried out on the two RFPexperiments. Controller models based on the mode harmonic control concept and on a state-space multipleinputmultiple-output intelligent shell concept are studied. Progress in development of optimal control schemesare presented both through experimental studies and simulations.
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| 62. |
- Dzieciatkowska, Monika, et al.
(författare)
-
Rapid method for sensitive screening of oligosaccharide epitopes in the lipooligosaccharide from Campylobacter jejuni strains isolated from Guillain-Barre syndrome and Miller Fisher syndrome patients
- 2008
-
Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:10, s. 3429-3436
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni lipooligosaccharide (LOS) can trigger Guillain-Barre syndrome (GBS) due to its similarity to human gangliosides. Rapid and accurate structural elucidation of the LOS glycan of a strain isolated from a GBS patient could help physicians determine the spectrum of anti-ganglioside antibodies likely to be found and therefore provide valuable assistance in establishing an appropriate course of treatment. The ability of implemented mass spectrometry-based approaches in a clinical setting has been limited by the laborious and time-consuming nature of the protocols, typically 3 to 4 days, used to prepare LOS. In order to improve the analytical throughput, microwave-assisted enzymatic digestion was investigated. In this study, the bacterial cells were suspended in 50 mu l of 20 mM ammonium acetate buffer containing DNase and RNase and treated by direct microwave irradiation for 3 min. Then, proteinase K was added and the samples were again microwaved. The intact LOS samples were analyzed using electrophoresis-assisted open-tubular liquid chromatography-mass spectrometry. The reliability of the rapid, high-throughput technique was demonstrated through analysis of LOS glycans from 73 C. jejuni strains. The structure was elucidated using material from a single colony. The total time for sample preparation and MS analysis is less than 60 min.
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| 63. |
- Ellis, T, et al.
(författare)
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Non-invasive measurement of cortisol and melatonin in tanks stocked with seawater Atlantic salmon
- 2007
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 272:1-4, s. 698-706
-
Tidskriftsartikel (refereegranskat)abstract
- This study examined the potential for non-invasive assessment of cortisol and melatonin status of seawater Atlantic salmon, by measurement of hormone release into the water using methodology developed recently for freshwater rainbow trout. Validation experiments demonstrated good recoveries of spiked cortisol (ca. 95%) and melatonin (ca. 85%) from seawater, that oxygenation of seawater did not affect recovery, and that only small losses occurred during freeze storage of samples. When groups of seawater Atlantic salmon were transferred to experimental tanks, water cortisol concentrations reduced over the first few days — indicating an acclimation response. Subsequent exposure to a handling stress caused a rapid 50-fold increase in water cortisol concentration, followed by a decrease. In a separate experiment, water cortisol levels were elevated in tanks of fish previously exposed to infectious pancreatic necrosis virus, and cortisol release rate was correlated to plasma cortisol level. Water sampling from tanks holding seawater salmon showed that water melatonin concentrations were elevated at night, conforming to expectation. These experiments demonstrate that the cortisol and melatonin status of seawater Atlantic salmon in tanks can be monitored non-invasively by water sampling, with the particular advantage that hormonal status can be tracked over time as the fish are not disturbed by sampling.
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| 64. |
- Evander, Mikael, et al.
(författare)
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Acoustic Differential Extraction - ultrasonic DNA-extraction from sexual assault evidence
- 2007
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Ingår i: International Congress on Ultrasonics. ; 1, s. 151-151
-
Konferensbidrag (refereegranskat)abstract
- Isolation of the male and female DNA is one of the most important steps in obtaining the DNA profile of the perpetrator in sexual assault cases. The sample is obtained by taking a vaginal swab containing both epithelial cells from the female and sperm cells from the male from the victim. The purity of the extracted male fraction decides whether or not a single-source DNA profile of the suspect will be obtained or not. The existing techniques are have poor separation efficiency, time-consuming, labour-intensive and are neither easily automated nor integrated with further analysis steps. A novel method of DNA extraction based on ultrasonic trapping, Acoustic Differential Extraction, has been developed. A microfluidic device using laminar flow valving and miniature PZT transducers retains the sperm cells while mobilizing the female fraction into a separate outlet. The device was evaluated using a mock sexual assault sample and the separated fractions were analyzed using quantitative PCR and STR-profiling. A 16-fold enrichment of the male fraction, making an originally hard-to-detect-male DNA profile readily profiled, has been demonstrated. The STR-profiling of the male and female fractions showed a male fraction purity of up to 99 % making it possible to obtain a single-source DNA-profile of the suspect. The microfluidic format of the device makes it possible to downscale the sample time from 4-8 hours to 10 minutes. It is also possible to integrate this method with further downstream analysis steps necessarey for the full forensic DNA analysis.
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| 65. |
- Evander, Mikael, et al.
(författare)
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Using Acoustic Differential Extraction to enhance analysis of sexual assualt evidence on a valveless glass microdevice
- 2006
-
Ingår i: Proceedings of µTAS 2006 Conference. ; 2, s. 1055-1057
-
Konferensbidrag (refereegranskat)abstract
- The isolation of male and female DNA is an important step in the analysis of sexual assault evidence. A vaginal swab with female epithelial cells and male sperm cells is obtained from the female, and it is vital to separate the male and female fractions in order to obtain a single-source DNA profile of the suspect. In the case of a low abundance of sperm cells, it is very important that no cells are lost in the isolation step. The conventional isolation method used in the forensic DNA laboratories, differential extraction, is a time-consuming step, requiring up to 24 hours. It is neither highly amenable to automation, nor can it be easily integrated with other steps of the analysis. Therefore, a novel method of performing the isolation of male and female fractions of biological material from sexual assault evidence has been developed, termed acoustic differential extraction (ADE). After selectively lysing the female epithelial cells while keeping the sperm cells intact, the sample, now containing sperm cells and female cell lysate, is infused in a 900 μm wide and 70 μm deep microfabricated glass channel with miniature piezoelectric transducers mounted at the bottom of the channel, as shown in Figure 1. Upon activation of the ultrasound, the sperm cells will be trapped in a standing wave1 while free DNA will not be retained. The sperm cells, levitated in the 3D fluidic space above the transducer, can be washed with buffer and the unretained biological material directed to an output reservoir. Using laminar flow valving2, the sperm cells can be released and directed into a separate output reservoir in anticipation of DNA analysis, see Figure 2. With the purpose of evaluating the ADE microdevice for the collection of the two output fractions (male and female), preliminary work used a mock sexual assault sample created with polystyrene microparticles as sperm cells and Evan's Blue dye as female cell lysate. The particles were trapped over the transducer and the dye was directed to the female outlet reservoir as shown in Figure 3. After washing the particles, the ultrasound was deactivated and the flow redirected in order to collect the particles in the male outlet reservoir. A biological sample consisting of sperm cells and lysed female epithelial cells was subsequently tested by infusion into the device for five minutes while trapping the sperm cells over the transducer (Figure 4). The trapped sperm cells were washed with PBS for five minutes, then released and collected for analysis off-chip. DNA from the isolated cells was extracted with a commercial DNA extraction kit and analyzed with a duplex quantitative PCR assay3 to show the sample purity. An example of the qPCR data obtained is provided in Table 1. The results show that a highly-enriched sperm cell fraction can be obtained with the ADE technique. It is reasonable to expect that this technique can be integrated with on-chip downstream sample processing, e.g. DNA extraction and amplification. This would greatly diminish the analysis time from 24 hours to approximately 60 minutes. The time savings, in combination with the possibility to create a fully automated system, gives the ADE technique the potential to significantly alter the means by which sexual assault evidence is processed in crime laboratories today.
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| 66. |
- Fioretos, Thoas, et al.
(författare)
-
Mechanisms underlying neoplasia-associated genomic rearrangements
- 2006
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Ingår i: Genomic disorders: The Genomic basis of disease. - Totowa, NJ : Humana Press. - 9781588295590 ; , s. 327-337
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Neoplastic disorders are characterized by recurrent somatically acquired chromosomal aberrations that alter the structure and/or expression of a large number of genes. Most “cancer genes” discovered to date in human neoplasms have been identified through isolation of genes at the breakpoints of balanced chromosomal translocations. Although functional studies of such cancer-causing genes have demonstrated their causal role in tumorigenesis, the mechanisms underlying the formation of recurrent chromosomal changes in cancer remain enigmatic. Low-copy repeats (LCRs) are important mediators of erroneous meiotic recombination, resulting in constitutional chromosomal rearrangements. Recently, LCRs have been implicated in the formation of the frequent and characteristic neoplasia-associated chromosomal aberrations t(9;22)(q34;q1 1) and i(17q), suggesting that similar genome architecture features may play an important role in generating also other somatic chromosomal rearrangements.
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| 67. |
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| 68. |
- Friedman, James S., et al.
(författare)
-
Mutations in a BTB-Kelch Protein, KLHL7, Cause Autosomal-Dominant Retinitis Pigmentosa
- 2009
-
Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 84:6, s. 792-800
-
Tidskriftsartikel (refereegranskat)abstract
- Retinitis pigmentosa (RP) refers to a genetically heterogeneous group of progressive neurodegenerative diseases that result in dysfunction and/or death of rod and cone photoreceptors in the retina. So far, 18 genes have been identified for autosomal-dominant (ad) RP. Here, we describe an adRP locus (RP42) at chromosome 7p15 through linkage analysis in a six-generation Scandinavian family and identify a disease-causing mutation, c.449G -> A (p.S150N), in exon 6 of the KLHL7 gene. Mutation screening of KLHL7 in 502 retinopathy probands has revealed three different missense mutations in six independent families. KLHL7 is widely expressed, including expression in rod photoreceptors, and encodes a 75 kDa protein of the BTB-Kelch Subfamily within the BTB superfamily. BTB-Kelch proteins have been implicated in ubiquitination through Cullin E3 ligases. Notably, all three putative disease-causing KLHL7 mutations are within a conserved BACK domain; homology modeling suggests that mutant amino acid side chains can potentially fill the cleft between two helices, thereby affecting the ubiquitination complexes. Mutations in an identical region of another BTB-Kelch protein, gigaxonin, have previously been associated with giant axonal neuropathy. Our studies suggest an additional role of the ubiquitin-proteasome protein-degradation pathway in maintaining neuronal health and in disease.
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| 69. |
- Friedman, James S., et al.
(författare)
-
Premature truncation of a novel protein, RD3, exhibiting subnuclear localization is associated with retinal degeneration
- 2006
-
Ingår i: American Journal of Human Genetics. - 0002-9297. ; 79:6, s. 1059-1070
-
Tidskriftsartikel (refereegranskat)abstract
- The rd3 mouse is one of the oldest identified models of early-onset retinal degeneration. Using the positional candidate approach, we have identified a C -> T substitution in a novel gene, Rd3, that encodes an evolutionarily conserved protein of 195 amino acids. The rd3 mutation results in a predicted stop codon after residue 106. This change is observed in four rd3 lines derived from the original collected mice but not in the nine wild-type mouse strains that were examined. Rd3 is preferentially expressed in the retina and exhibits increasing expression through early postnatal development. In transiently transfected COS-1 cells, the RD3-fusion protein shows subnuclear localization adjacent to promyelocytic leukemia-gene-product bodies. The truncated mutant RD3 protein is detectable in COS-1 cells but appears to get degraded rapidly. To explore potential association of the human RD3 gene at chromosome 1q32 with retinopathies, we performed a mutation screen of 881 probands from North America, India, and Europe. In addition to several alterations of uncertain significance, we identified a homozygous alteration in the invariant G nucleotide of the RD3 exon 2 donor splice site in two siblings with Leber congenital amaurosis. This mutation is predicted to result in premature truncation of the RD3 protein, segregates with the disease, and is not detected in 121 ethnically matched control individuals. We suggest that the retinopathy-associated RD3 protein is part of subnuclear protein complexes involved in diverse processes, such as transcription and splicing.
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| 70. |
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