| 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. |
- Adler, SS, et al.
(författare)
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PHENIX on-line systems
- 2003
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 560-592
-
Tidskriftsartikel (refereegranskat)abstract
- The PHENIX On-Line system takes signals from the Front End Modules (FEM) on each detector subsystem for the purpose of generating events for physics analysis. Processing of event data begins when the Data Collection Modules (DCM) receive data via fiber-optic links from the FEMs. The DCMs format and zero suppress the data and generate data packets. These packets go to the Event Builders (EvB) that assemble the events in final form. The Level-1 trigger (LVL1) generates a decision for each beam crossing and eliminates uninteresting events. The FEMs carry out all detector processing of the data so that it is delivered to the DCMs using a standard format. The FEMs also provide buffering for LVL1 trigger processing and DCM data collection. This is carried out using an architecture that is pipelined and deadtimeless. All of this is controlled by the Master Timing System (MTS) that distributes the RHIC clocks. A Level-2 trigger (LVL2) gives additional discrimination. A description of the components and operation of the PHENIX On-Line system is given and the solution to a number of electronic infrastructure problems are discussed. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Bower, K. N., et al.
(författare)
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ACE-2 HILLCLOUD. An overview of the ACE-2 ground-based cloud experiment
- 2000
-
Ingår i: Tellus. Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 0280-6509. ; 52:2, s. 750-778
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Tidskriftsartikel (refereegranskat)abstract
- The ACE-2 HILLCLOUD experiment was carried out on the island of Tenerife in June-July 1997 to investigate the interaction of the boundary layer aerosol with a hill cap cloud forming over a ridge to the north-east of the island. The cloud was used as a natural flow through reactor to investigate the dependence of the cloud microphysics and chemistry on the characteristics of the aerosols and trace gases entering cloud, and to simultaneously study the influence of the physical and chemical processes occurring within the cloud on the size distribution, chemical and hygroscopic properties of the aerosol exiting cloud. 5 major ground base sites were used, measuring trace gases and aerosols upwind and downwind of the cloud, and cloud microphysics and chemistry and interstitial aerosol and gases within the cloud on the hill. 8 intensive measurement periods or runs were undertaken during cloud events, (nocturnally for seven of the eight runs) and were carried out in a wide range of airmass conditions from clean maritime to polluted continental. Polluted air was characterised by higher than average concentrations of ozone (> 50 ppbv), fine and accumulation mode aerosols (> 3000 and > 1500 cm -3 , respectively) and higher aerosol mass loadings. Cloud droplet number concentrations N, increased from 50 cm -3 in background maritime air to > 2500 cm -3 in aged polluted continental air, a concentration much higher than had previously been detected. Surprisingly, N was seen to vary almost linearly with aerosol number across this range. The droplet aerosol analyser (DAA) measured higher droplet numbers than the corrected forward scattering spectrometer probe (FSSP) in the most polluted air, but at other times there was good agreement (FSSP = 0.95 DAA with an r 2 = 0.89 for N < 1200 cm -3 ). Background ammonia gas concentrations were around 0.3 ppbv even in air originating over the ocean, another unexpected but important result for the region. NO 2 was present in background concentrations of typically 15 pptv to 100 pptv and NO 3 . (the nitrate radical) was observed at night throughout. Calculations suggest NO 3 . losses were mainly by reaction with DMS to produce nitric acid. Low concentrations of SO 2 (~30 pptv), HNO 3 and HCl were always present. HNO 3 concentrations were higher in polluted episodes and calculations implied that these exceeded those which could be accounted for by NO 2 oxidation. It is presumed that nitric and hydrochloric acids were present as a result of outgassing from aerosol, the HNO 3 from nitrate rich aerosol transported into the region from upwind of Tenerife, and HCl from sea salt aerosol newly formed at the sea surface. The oxidants hydrogen peroxide and ozone were abundant (i.e., were well in excess over SO 2 throughout the experiment). Occasions of significant aerosol growth following cloud processing were observed, particularly in cleaner cases. Observations and modelling suggested this was due mainly to the take up of nitric acid, hydrochloric acid and ammonia by the smallest activated aerosol particles. On a few occasions a small contribution was made by the in-cloud oxidation of S(IV). The implications of these results from HILLCLOUD for the climatologically more important stratocumulus Marine Boundary Layer (MBL) clouds are considered.
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| 4. |
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| 5. |
- Degen, Winfried G. J., et al.
(författare)
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Characterization of recombinant human autoantibody fragments directed toward the autoantigenic U1-70K protein
- 2000
-
Ingår i: European Journal of Immunology. - : Wiley-VCH Verlagsgesellschaft. - 0014-2980 .- 1521-4141. ; 30:10, s. 3029-3038
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Tidskriftsartikel (refereegranskat)abstract
- The U1-70K protein is specifically bound to stemloop I of the U1 small nuclear RNA contained in the U1 small nuclear ribonucleoprotein complex (U1 snRNP), which is involved in the splicing of pre-mRNA. All components of the U1 snRNP complex, including the U1-70K protein, are important autoantigens in patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Here we describe for the first time the selection and characterization of recombinant human anti-U1-70K single chain autoantibody fragments (anti-hU1-70K scFv) from autoimmune patient-derived phage display antibody libraries. All scFv specifically recognize parts of the hU1-70K protein and its apoptotic 40-kDa cleavage product. In Western blotting assays a number of scFv preferentially recognize the 40-kDa apoptotic cleavage fragment of the U1-70K protein, suggesting a possible involvement of this apoptotic cleavage product in the autoimmune response of patients. The germline gene usage of these recombinant autoantibodies was also determined. Using several U1-70K deletion and point mutants of both human (h) and Drosophila melanogaster (Dm) origin, it was established that the U1-70K epitope that is recognized by the anti-hU1-70K scFv is located within the RNA binding domain.
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| 6. |
- Hampel, H, et al.
(författare)
-
Core biological marker candidates of Alzheimer's disease - perspectives for diagnosis, prediction of outcome and reflection of biological activity.
- 2004
-
Ingår i: Journal of neural transmission (Vienna, Austria : 1996). - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 111:3, s. 247-72
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Forskningsöversikt (refereegranskat)abstract
- Alzheimer's disease (AD) is a complex neurodegenerative dementing illness. Over the past few years, however, remarkable advances have taken place in understanding both the genetic and molecular biology with the intracellular processing of amyloid and tau and the changes leading to the pathologic formation of extracellular amyloid plaques and the intraneuronal aggregation of hyperphosphorylated tau into neurofibrillary tangles. This progress in our understanding of the molecular pathology has set the stage for clinically meaningful advances in the development of biomarkers. Emerging diagnostic methods that are based on biochemical and imaging biomarkers of disease specific pathology hold the potential to provide effective measures of natural history (marker of disease that is predictive of outcome), biological activity (such as magnitude and frequency of response correlating with drug potency) and markers of surrogate endpoints (single or composite marker that accounts for clinical benefit of the therapy). Markers of biological activity should be also evaluated regarding their value to reflect disease progression, heterogeneity of the clinical population, for early decision making and characterization of new treatments. We focussed on the current status of core analytes which provide reasonable evidence for association with key mechanisms of pathogenesis or neurodegeneration in AD. In addition, feasibility was important, such as availability of a validated assay for the biological measure in question, with properties that included high precision and reliability of measurement, reagents and standards well described. On this basis we reviewed the body of literature that has examined CSF total tau (t-tau) and beta-amyloid 1-42 (Abeta(1-42)), phosphorylated tau (p-tau) and beta-amyloid-antibodies as diagnostic tests for AD versus clinically representative comparison groups. Measurement of t-tau and Abeta(1-42) in the CSF seems useful to discriminate early and incipient AD from age-associated memory-impairment, depression, and some secondary dementias. First studies showed that measurement of p-tau proteins significantly improves early and differential diagnosis, as well as disease prediction in subjects at risk for AD and comes closest to fulfilling proposed criteria of a biological marker for AD. However, the nature of the majority of reported findings are still preliminary and retrospective. General issues for biomarkers have to be adequately addressed, such as sensitivity of the method, frequency of assessments, stability of the method, standardization of methods and dynamic range. There is still a partial lack of comparison patient populations that must be addressed in future studies. International dementia networks have been recently established to advance the establishment of core biomarker candidates of AD as potential surrogate endpoints for clinical trials and their clinical use for predictive and diagnostic purposes.
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| 7. |
- Swietlicki, Erik, et al.
(författare)
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Hygroscopic properties of aerosol particles in the northeastern Atlantic during ACE-2
- 2000
-
Ingår i: Tellus. Series B: Chemical and Physical Meteorology. - : Stockholm University Press. - 0280-6509 .- 1600-0889. ; 52:2, s. 201-227
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Tidskriftsartikel (refereegranskat)abstract
- Measurements of the hygroscopic properties of sub-micrometer atmospheric aerosol particles were performed with hygroscopic tandem differential mobility analysers (H-TDMA) at 5 sites in the subtropical north-eastern Atlantic during the second Aerosol Characterization Experiment (ACE-2) from 16 June to 25 July 1997. Four of the sites were in the marine boundary layer and one was, at least occasionally, in the lower free troposphere. The hygroscopic diameter growth factors of individual aerosol particles in the dry particle diameter range 10-440 nm were generally measured for changes in relative humidity (RH) from <10% to 90%. In the marine boundary layer, growth factors at 90% RH were dependent on location, air mass type and particle size. The data was dominated by a unimodal growth distribution of more-hygroscopic particles, although a bimodal growth distribution including less-hygroscopic particles was observed at times, most often in the more polluted air masses. In clean marine air masses the more-hygroscopic growth factors ranged from about 1.6 to 1.8 with a consistent increase in growth factor with increasing particle size. There was also a tendency toward higher growth factors as sodium to sulphate molar ratio increased with increasing sea-salt contribution at higher wind speeds. During outbreaks of European pollution in the ACE-2 region, the growth factors of the largest particles were reduced, but only slightly. Growth factors at all sizes in both clean and polluted air masses were markedly lower at the Sagres, Portugal site due to more proximate continental influences. The frequency of occurrence of less-hygroscopic particles with a growth factor of ca. 1.15 was greatest during polluted conditions at Sagres. The free tropospheric 50 nm particles were predominately less-hygroscopic, with an intermediate growth factor of 1.4, but more-hygroscopic particles with growth factors of about 1.6 were also frequent. While these particles probably originate from within the marine boundary layer, the less-hygroscopic particles are probably more characteristic of lower free tropospheric air masses. For those occasions when measurements were made at 90% and an intermediate 60% or 70% RH, the growth factor G(RH) of the more-hygroscopic particles could be modelled empirically by a power law expression. For the ubiquitous more-hygroscopic particles, the expressions G(RH) = (1 - RH/100)-0.210 for 50 nm Aitken mode particles and G(RH) = (1 - RH/100)-0.233 for 166 nm accumulation mode particles are recommended for clean marine air masses in the north-eastern Atlantic within the range 0 < RH < 95%, and for wind speeds for which the local sea-salt production is small (< ca. 8 m s-1).
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| 8. |
- Alsmark, Cecilia M., et al.
(författare)
-
The louse-borne human pathogen Bartonella quintana is a genomic derivative of the zoonotic agent Bartonella henselae
- 2004
-
Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 101:26, s. 9716-9721
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Tidskriftsartikel (refereegranskat)abstract
- We present the complete genomes of two human pathogens, Bartonella quintana (1,581,384 bp) and Bartonella henselae (1,931,047 bp). The two pathogens maintain several similarities in being transmitted by insect vectors, using mammalian reservoirs, infecting similar cell types (endothelial cells and erythrocytes) and causing vasculoproliferative changes in immunocompromised hosts. A primary difference between the two pathogens is their reservoir ecology. Whereas B. quintana is a specialist, using only the human as a reservoir, B. henselae is more promiscuous and is frequently isolated from both cats and humans. Genome comparison elucidated a high degree of overall similarity with major differences being B. henselae specific genomic islands coding for filamentous hemagglutinin, and evidence of extensive genome reduction in B. quintana, reminiscent of that found in Rickettsia prowazekii. Both genomes are reduced versions of chromosome I from the highly related pathogen Brucella melitensis. Flanked by two rRNA operons is a segment with similarity to genes located on chromosome II of B. melitensis, suggesting that it was acquired by integration of megareplicon DNA in a common ancestor of the two Bartonella species. Comparisons of the vector-host ecology of these organisms suggest that the utilization of host-restricted vectors is associated with accelerated rates of genome degradation and may explain why human pathogens transmitted by specialist vectors are outnumbered by zoonotic agents, which use vectors of broad host ranges.
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| 9. |
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| 10. |
- Berglund, Sten, 1947-, et al.
(författare)
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The diversity of post-communist Europe
- 2004. - 2
-
Ingår i: The handbook of political change in Eastern Europe. - Cheltenham : Edward Elgar. - 1840648546 ; , s. 1-12
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 11. |
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| 12. |
- Hedborg, Fredrik, et al.
(författare)
-
Evidence for hypoxia-induced neuronal-to-chromaffin metaplasia in neuroblastoma
- 2003
-
Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 17, s. 598-
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Tidskriftsartikel (refereegranskat)abstract
- We present evidence that in neuroblastoma, a pediatric malignancy of embryonal sympathetic origin, hypoxia, underlies a phenotypic switch from a primitive neuronal to a chromaffin cell type. This conclusion is based on morphological and molecular data on 116 clinical tumors and is supported by data on the phenotypic effects of hypoxia on neuroblastoma cell lines when studied in monolayer culture and as tumor xenografts. In the clinical material, extensive chromaffin features were seen in regions of chronic tumor hypoxia. This was the exclusive form of intra-tumoral maturation of stroma-poor tumors and was also seen in stroma-rich tumors, either exclusively or in combination with ganglion-like cells. In neuroblastoma cell lines, hypoxia induced changes in gene expression associated with the chromaffin features observed in vivo. We therefore propose tumor hypoxia as a major cue determining phenotype in sympathetic tumors of neuroblastic origin. Because it appears to be reversible upon reoxygenation in monolayer culture, we suggest the term metaplasia for the phenomenon.
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| 13. |
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| 14. |
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| 15. |
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| 16. |
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| 17. |
- Kvien, TK, et al.
(författare)
-
Long term efficacy and safety of cyclosporin versus parenteral old in early rheumatoid arthritis: a three year study of radiographic progression, renal function, and arterial hypertension
- 2002
-
Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 61:6, s. 511-516
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare the three year safety and efficacy of cyclosporin and parenteral gold in the treatment of early, active, severe rheumatoid arthritis (RA), and to study the reversibility of cyclosporin associated renal dysfunction in patients who discontinued cyclosporin treatment. Methods: The patients continued to receive cyclosporin or parenteral gold in an 18 month open extension to an 18 month randomised, parallel group study. The main efficacy variable was blinded evaluation of radiographic progression of joint damage, Safety variables included serum creatinine, calculated creatinine clearance, and blood pressure. Results: Radiographic progression during follow up was similar in both groups. About 60% of the patients in the intention to treat groups (n=272) and about half of the patients in the completer groups (n=114) had definite radiographic progression in joint damage (increases >6 in the Larsen-Dale score), and about one in three also had substantial progression (>18 increase in Larsen-Dale score). Both systolic and diastolic blood pressure were significantly increased in the cyclosporin group compared with the gold group, and 12/139 (9%) versus 3/139 (2%) (p=0.03) had notably raised blood pressure. The mean serum creatinine increased by 28% at the treatment end point in the cyclosporin group as compared with 7% in the gold group, The mean calculated creatinine clearance was reduced by 16% and increased by 1% in the cyclosporin and gold groups, respectively, at the end of the study. At the final follow up visit after discontinuation of cyclosporin (at least three months after treatment was stopped) the mean serum creatinine was increased by 15% and creatinine clearance reduced by 16%. Sustained increases in serum creatinine at this post-treatment end point were mostly seen in patients with a raised serum creatinine during treatment of at least 50%. Conclusion: Three year changes in radiographic damage during cyclosporin and parenteral gold were similar in patients with early, active RA. Abnormal renal function and raised blood pressure were often seen in the cyclosporin treated patients.
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| 18. |
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| 19. |
- Martinsson, Bengt G., et al.
(författare)
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Validation of very high cloud droplet number concentrations in air masses transported thousands of kilometres over the ocean
- 2000
-
Ingår i: Tellus. Series B: Chemical and Physical Meteorology. - 0280-6509. ; 52:2, s. 801-814
-
Tidskriftsartikel (refereegranskat)abstract
- The microstructure of orographic clouds related to the aerosol present was studied during the second Aerosol Characterisation Experiment (ACE-2). Very high cloud droplet number concentrations (almost 3000 cm -3 ) were observed. These high concentrations occurred when clouds formed on a hill slope at Tenerife in polluted air masses originating in Europe that had transported the order of 1000 km over the Atlantic Ocean. The validity of the measured droplet number concentrations was investigated by comparing with measurements of the aerosol upstream of the cloud and cloud interstitial aerosol. Guided by distributions of the ratios between the measurements, three criteria of typically 30% in maximum deviation were applied to the measurements to test their validity. Agreement was found for 88% of the cases. The validated data set spans droplet number concentrations of 150-3000 cm -3 . The updraught velocity during the cloud formation was estimated to 2.2 m s -1 by model calculations, which is typical of cumuliform clouds. The results of the present study are discussed in relation to cloud droplet number concentrations previously reported in the literature. The importance of promoting the mechanistic understanding of the aerosol/cloud interaction and the use of validation procedures of cloud microphysical parameters is stressed in relation to the assessment of the indirect climatic effect of aerosols.
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| 20. |
- Neumann, Patrick, et al.
(författare)
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Trunk posture: reliability, accuracy, and risk estimates for low back pain from a video based assessment method
- 2001
-
Ingår i: International Journal of Industrial Ergonomics. - 0169-8141. ; 28, s. 355-365
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Tidskriftsartikel (refereegranskat)abstract
- It has been recently reported that both dynamic movement characteristics, as well as the duration of postures adopted during work, are important in the development of low back pain (LBP). This paper presents a video-based posture assessment method capable of measuring trunk angles and angular velocities in industrial workplaces. The interobserver reliability, system accuracy, and the relationship of the measured exposures to the reporting of low back pain are reported. The video analysis workstation consisted of a desktop computer equipped with digital video capture and playback technology, a VCR, and a computer game type joystick. The operator could then use a joystick to track trunk flexion and lateral bending during computer-controlled video playback. The joystick buttons were used for binary input of twisting. The inter-observer reliability for peak flexion and percentage of time spent in posture category variables were excellent (ICC>0.8). Lower reliability levels were observed for peak and average velocity and movement related variables. The video analysis system time series data showed very high correlation to the criterion optoelectronic imaging system (r ¼ 0:92). Root mean square errors averaged 5.81 for the amplitude probability distribution function data. Trunk flexion variables including peak level, peak velocity, average velocity indicators, and percent time in flexion category indicators all showed significant differences between cases and controls in the epidemiological study. A model consisting of the measures peak trunk flexion, percent time in lateral bend and average lateral bending velocity emerged after multivariable analysis for relationship to low back pain.
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| 21. |
- Polivka, Tomas, et al.
(författare)
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Ultrafast formation of a carotenoid radical in LH2 antenna complexes of purple bacteria
- 2004
-
Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 108:39, s. 15398-15407
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Tidskriftsartikel (refereegranskat)abstract
- The SI-mediated carotenoid to BChl a energy-transfer pathway and carotenoid radical formation have been studied using femtosecond time-resolved transient absorption spectroscopy. A series of LH2 complexes (LH2 = light-harvesting complex 2) from Rhodobacter sphaeroides incorporating carotenoids neurosporene, spheroidene, and spheroidenone were used to explore the effect of conjugation length. The S, lifetimes of carotenoids in the LH2 complex are significantly shorter than in solution, resulting in efficiencies of the S-1-mediated energy transfer of 94%, 82%, and 76%, respectively. In addition to the S-1 decay, a low-amplitude component of similar to9 ps was revealed for all carotenoids in LH2 and assigned to the S* state. Besides energy transfer, excitation of the carotenoid S-2 state in LH2 complexes also leads to the formation of a carotenoid radical, and this pathway is also conjugation length dependent. The carotenoid radical is formed as a result of electron transfer between the carotenoid and B800 BChl a molecules. The yield of the radical formation is highest for neurosporene (10-15%), while a lower efficiency was observed for spheroidene (5-8%). For spheroidenone, no distinct radical signal was found, The precursor of the carotenoid radical is a charge-transfer state that is populated directly from the S-2 state. This charge-transfer state, which represents an excited state of the carotenoid-B800 complex, decays in 300 fs (neurosporene) or 400 fs (spheroidene) to form ground-state carotenoid cation and BChl anion. The charge-separated state has a lifetime of 2 ps (neurosporene) and 8 ps (spheroidene).
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| 22. |
- Ristow, Michael, et al.
(författare)
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Frataxin deficiency in pancreatic islets causes diabetes due to loss of β cell mass
- 2003
-
Ingår i: Journal of Clinical Investigation. - 0021-9738. ; 112:4, s. 527-534
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Tidskriftsartikel (refereegranskat)abstract
- Diabetes is caused by an absolute (type 1) or relative (type 2) deficiency of insulin-producing β cells. We have disrupted expression of the mitochondrial protein frataxin selectively in pancreatic β cells. Mice were born healthy but subsequently developed impaired glucose tolerance progressing to overt diabetes mellitus. These observations were explained by impairment of insulin secretion due to a loss of β cell mass in knockout animals. This phenotype was preceded by elevated levels of reactive oxygen species in knockout islets, an increased frequency of apoptosis, and a decreased number of proliferating β cells. Hence, disruption of the frataxin gene in pancreatic β cells causes diabetes following cellular growth arrest and apoptosis, paralleled by an increase in reactive oxygen species in islets. These observations might provide insight into the deterioration of β cell function observed in different subtypes of diabetes in humans.
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| 23. |
- Schänzer, Anne, et al.
(författare)
-
Direct stimulation of adult neural stem cells in vitro and neurogenesis in vivo by vascular endothelial growth factor.
- 2004
-
Ingår i: Brain pathology (Zurich, Switzerland). - 1015-6305. ; 14:3, s. 237-48
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Tidskriftsartikel (refereegranskat)abstract
- Hypoxia as well as global and focal ischemia are strong activators of neurogenesis in the adult mammalian central nervous system. Here we show that the hypoxia-inducible vascular endothelial growth factor (VEGF) and its receptor VEGFR-2/Flk-1 are expressed in clonally-derived adult rat neural stem cells in vitro. VEGF stimulated the expansion of neural stem cells whereas blockade of VEGFR-2/Flk-1-kinase activity reduced neural stem cell expansion. VEGF was also infused into the lateral ventricle to study changes in neurogenesis in the ventricle wall, olfactory bulb and hippocampus. Using a low dose (2.4 ng/d) to avoid endothelial proliferation and changes in vascular permeability, VEGF stimulated adult neurogenesis in vivo. After VEGF infusion, we observed reduced apoptosis but unaltered proliferation suggesting a survival promoting effect of VEGF in neural progenitor cells. Strong expression of VEGFR-2/Flk-1 was detected in the ventricle wall adjacent to the choroid plexus, a site of significant VEGF production, which suggests a paracrine function of endogenous VEGF on neural stem cells in vivo. We propose that VEGF acts as a trophic factor for neural stem cells in vitro and for sustained neurogenesis in the adult nervous system.These findings may have implications for the pathogenesis and therapy of neurodegenerative diseases.
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| 24. |
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| 25. |
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| 26. |
- Wierup, Nils, et al.
(författare)
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The ghrelin cell: a novel developmentally regulated islet cell in the human pancreas.
- 2002
-
Ingår i: Regulatory Peptides. - 1873-1686. ; 107:1-3, s. 63-69
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Ghrelin, an endogenous ligand of the growth hormone secretagogue receptor (GHS-R), was recently identified in the stomach. Ghrelin is produced in a population of endocrine cells in the gastric mucosa, but expression in intestine, hypothalamus and testis has also been reported. Recent data indicate that ghrelin affects insulin secretion and plays a direct role in metabolic regulation and energy balance. On the basis of these findings, we decided to examine whether ghrelin is expressed in human pancreas. Specimens from fetal to adult human pancreas and stomach were studied by immunocytochemistry, for ghrelin and islet hormones, and in situ hybridisation, for ghrelin mRNA. RESULTS: We identified ghrelin expression in a separate population of islet cells in human fetal, neonatal, and adult pancreas. Pancreatic ghrelin cells were numerous from midgestation to early postnatally (10% of all endocrine cells). The cells were few, but regularly seen in adults as single cells at the islet periphery, in exocrine tissue, in ducts, and in pancreatic ganglia. Ghrelin cells did not express any of the known islet hormones. In fetuses, at midgestation, ghrelin cells in the pancreas clearly outnumbered those in the stomach. CONCLUSIONS: Ghrelin is expressed in a quite prominent endocrine cell population in human fetal pancreas, and ghrelin expression in the pancreas precedes by far that in the stomach. Pancreatic ghrelin cells remain in adult islets at lower numbers. Ghrelin is not co-expressed with any known islet hormone, and the ghrelin cells may therefore constitute a new islet cell type.
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| 27. |
- Zetterholm, Elisabeth, et al.
(författare)
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Why Foil 4? A first look
- 2003
-
Ingår i: Proceedings from Fonetik 2003 ; Phonum 9. - 9173054305 ; 9, s. 161-164
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Recent studies have shown that ability to recognize an imitated voice is affected by topic and familiarity with the person being imitated. The signal detection methods used in those studies give no specific information about the distribution of non matching positive responses (false alarms) amongst voices used as distracters (foils). This paper shows that there was a selective listener preference for Foil 4. However, preliminary comparison of Foil 4 with the target imitated voice has not revealed conclusively any similarities in speech features that account for listeners’ preferential selection.
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| 28. |
- Zigmantas, Donatas, et al.
(författare)
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Effect of a conjugated carbonyl group on the photophysical properties of carotenoids
- 2004
-
Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084. ; 6:11, s. 3009-3016
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Tidskriftsartikel (refereegranskat)abstract
- Effects of introducing a carbonyl group into the conjugation system of carotenoids were studied for four naturally occurring carotenoids: peridinin, fucoxanthin, siphonaxanthin and spheroidenone. The conjugated carbonyl group affects energetics and dynamics of all these carotenoids in a similar way, although the magnitude of the changes depends strongly on the carotenoid structure. Firstly, presence of a carbonyl group considerably narrows the S-1/ICT-S-2 gap, and this effect does not depend on polarity. The S-1/ICT energies of carotenoids were measured by recording S-1/ICT-S-2 spectral profiles in the near-infrared region and the resulting energies were 16100 cm(-1) for peridinin, 16520 cm(-1) for fucoxanthin and 16610 cm(-1) for siphonaxanthin. Narrowing of the S-1/ICT-S-2 gap has important consequences for functionality of these carotenoids in light-harvesting systems of oceanic organisms. since while the S, state is red-shifted to capture green light, the S-1/ICT state is still high enough to transfer energy to chlorophyll. The S-1/ICT energy of spheroidenone was determined to be 13000 cm(-1) Secondly the carbonyl group introduces some polarity-dependent effects: (1) polarity-induced change of the S-1/ICT lifetime. When changing from nonpolar to polar solvent, the S-1/ICT lifetime is changed from 160 to 8.5 ps for peridinin, from 60 to 30 ps for fucoxanthin, from 60 to 20 ps for fucoxanthin, while for the longer carotenoid spheroidenone the S-1/ICT lifetime remains 6 ps regardless of solvent polarity. This effect is explained in terms of stabilizatior of charge-transfer character of both ground and excited states. (2) stabilization of the charge-transfer character in polar solvents is also demonstrated by appearance of new polarity-induced bands in the transient absorption spectra. (3) polarity-induced changes of the ground state are manifested by asymmetric broadening of the absorption spectrum accompanied by a loss of vibrational structure.
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