| 1. |
- Hassler, B., et al.
(författare)
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Past changes in the vertical distribution of ozone - Part 1: Measurement techniques, uncertainties and availability
- 2014
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 7:5, s. 1395-1427
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Tidskriftsartikel (refereegranskat)abstract
- Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid- to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given.
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| 2. |
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| 3. |
- Lossow, Stefan, 1977, et al.
(författare)
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The SPARC water vapour assessment II: Profile-to-profile comparisons of stratospheric and lower mesospheric water vapour data sets obtained from satellites
- 2019
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Ingår i: Atmospheric Measurement Techniques. - : Copernicus GmbH. - 1867-1381 .- 1867-8548. ; 12:5, s. 2693-2732
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Tidskriftsartikel (refereegranskat)abstract
- This work is distributed under the Creative Commons Attribution 4.0 License. Within the framework of the second SPARC (Stratosphere-troposphere Processes And their Role in Climate) water vapour assessment (WAVAS-II), profile-to-profile comparisons of stratospheric and lower mesospheric water vapour were performed by considering 33 data sets derived from satellite observations of 15 different instruments. These comparisons aimed to provide a picture of the typical biases and drifts in the observational database and to identify data-set-specific problems. The observational database typically exhibits the largest biases below 70 hPa, both in absolute and relative terms. The smallest biases are often found between 50 and 5 hPa. Typically, they range from 0.25 to 0.5 ppmv (5 % to 10 %) in this altitude region, based on the 50 % percentile over the different comparison results. Higher up, the biases increase with altitude overall but this general behaviour is accompanied by considerable variations. Characteristic values vary between 0.3 and 1 ppmv (4 % to 20 %). Obvious data-set-specific bias issues are found for a number of data sets. In our work we performed a drift analysis for data sets overlapping for a period of at least 36 months. This assessment shows a wide range of drifts among the different data sets that are statistically significant at the 2 σ uncertainty level. In general, the smallest drifts are found in the altitude range between about 30 and 10 hPa. Histograms considering results from all altitudes indicate the largest occurrence for drifts between 0.05 and 0.3 ppmv decade-1. Comparisons of our drift estimates to those derived from comparisons of zonal mean time series only exhibit statistically significant differences in slightly more than 3 % of the comparisons. Hence, drift estimates from profile-to-profile and zonal mean time series comparisons are largely interchangeable. As for the biases, a number of data sets exhibit prominent drift issues. In our analyses we found that the large number of MIPAS data sets included in the assessment affects our general results as well as the bias summaries we provide for the individual data sets. This is because these data sets exhibit a relative similarity with respect to the remaining data sets, despite the fact that they are based on different measurement modes and different processors implementing different retrieval choices. Because of that, we have by default considered an aggregation of the comparison results obtained from MIPAS data sets. Results without this aggregation are provided on multiple occasions to characterise the effects due to the numerous MIPAS data sets. Among other effects, they cause a reduction of the typical biases in the observational database.
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| 4. |
- Hickery, Mark, et al.
(författare)
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Age-related changes in the response of human articular cartilage to IL-1 alpha and transforming growth factor-beta (TGF-beta) - Chondrocytes exhibit a diminished sensitivity to TGF-beta
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:52, s. 53063-53071
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Tidskriftsartikel (refereegranskat)abstract
- Cartilage glycosaminoglycan (GAG) synthesis and composition, upon which its structural integrity depends, varies with age, is modified by anabolic and catabolic stimuli, and is regulated by UDP-glucuronate availability. However, how such stimuli, prototypically represented by transforming growth factor-beta1 (TGF-beta1) and IL-1alpha, modify GAG synthesis during aging of normal human articular cartilage is not known. Using explants, we show that chondroitin sulfate (CS): total GAG ratios decrease, whereas C6S:C4S ratios increase with cartilage maturation, and that chondrocytes in the cartilage mid-zone, but not the superficial or deep zones, exhibit uridine 5'-diphosphoglucose dehydrogenase (UDPGD) activity, which is also increased in mature cartilage. We also show that IL-1alpha treatment reduces both total GAG and CS synthesis, decreases C6S: C4S ratios (less C6S), but fails to modify chondrocyte UDPGD activity at all ages. On the other hand, TGF-beta1 increases total GAG synthesis in immature, but not mature, cartilage (stimulates CS but not non-CS), age-independently decreases C6S:C4S (more C4S), and increases chondrocyte UDPGD activity in a manner inversely correlated with age. Our findings show that TGF-beta1, but not IL-1alpha, modifies matrix synthesis such that its composition more closely resembles "less mature" articular cartilage. These effects of TGF-beta1, which appear to be restricted to periods of skeletal immaturity, are closely associated although not necessarily mechanistically linked with increases in chondrocyte UDPGD activity. The antianabolic effects of IL-1alpha are, on the other hand, likely to be independent of any direct modification in UDPGD activity and manifest equally in human cartilage of all ages.
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| 6. |
- Skioldebrand, E, et al.
(författare)
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Enhanced concentration of COMP (cartilage oligomeric matrix protein) in osteochondral fractures from racing Thoroughbreds
- 2005
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Ingår i: Journal of Orthopaedic Research. - : Wiley. - 1554-527X .- 0736-0266. ; 23:1, s. 156-163
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to correlate the levels of COMP and aggrecan as indicators of tissue damage, in synovial fluid (sf) from carpal joints of acutely lame racehorses, with macroscopical lesions of articular cartilage (OA). osteochondral fractures and ligament tears found at arthroscopy. Sixty-three lame horses [49 Standardbred trotters (STB) and 14 Thoroughbreds (TB)] in conventional training and racing that underwent arthroscopy of their middle carpal or radiocarpal joints were included in the study. Intact as well as fragmented COMP and aggrecan released into the synovial fluid were quantified by western blot analyses and ELISA. The expression of COMP in tissues was estimated by mRNA in situ hybridisation and protein immununolocalisation in cartilage and osteochondral fractures. The concentration of sf-COMP was higher in TB with an osteochondral fracture than in STB with osteochondral fractures and TB and STB with OA. The chondrocytes in middle and deep zones of the articular cartilage of the osteochondral fragments (from a TB) expressed COMP mRNA, in contrast to the cartilage on the opposite side of the fracture where no expression was detected. In the synovial fluid from a joint (TB) with osteochondral fractures only intact COMP was present, whereas, fragmented COMP was more prominent in synovial fluid from a joint with OA. The concentration of sf-aggrecan did not differ between the two breeds, or between different lesions. The increased concentration of sf-COMP in TB with osteochondral fractures, but not in synovial fluid from equine joints with OA, is a novel finding. The results from this study indicate that elevated sf-COMP concentration in the joints of Thoroughbreds may be a useful marker for carpal joint osteochondral fragments.
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| 7. |
- Smith, Matthew R W, et al.
(författare)
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Increased Cartilage Oligomeric Matrix Protein Concentrations in Equine Digital Flexor Tendon Sheath Synovial Fluid Predicts Intrathecal Tendon Damage.
- 2011
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Ingår i: Veterinary surgery : VS : the official journal of the American College of Veterinary Surgeons. - 1532-950X. ; Dec, s. 54-58
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To evaluate digital flexor tendon sheath (DFTS) synovial fluid cartilage oligomeric matrix protein (COMP) concentrations as a molecular marker for intrathecal pathology. Study Design: Case control study. Animals: Horses (n=46) with DFTS tenosynovitis; 23 fresh cadaver horses. Methods: DFTS synovial fluid samples were collected from clinical cases with noninfected DFTS tenosynovitis and from control DFTS. Clinical and surgical findings were recorded, and dissection of control limbs was performed to confirm the DFTS to be grossly normal. Synovial fluid COMP was quantified using a homologous competitive inhibition ELISA. Results: Abnormalities were identified tenoscopically: intrathecal tendon/ligament tearing was identified in 37 cases and 9 had other lesions. In control horses, synovial fluid COMP was higher in younger horses. Clinical cases with intrathecal tendon/ligament tearing had higher synovial fluid COMP than either clinical cases with other lesions, or controls. In horses ≥5 years old, the sensitivity and specificity of the assay was high for diagnosing intrathecal tendon/ligament tearing. Conclusions: COMP concentrations in DFTS synovial fluid were significantly greater than those in normal horses with noninfected tenosynovitis caused by intrathecal tendon/ligament tearing, but not by other lesions.
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| 8. |
- Sodersten, F, et al.
(författare)
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Ultrastructural immunolocalization of cartilage oligomeric matrix protein (COMP) in relation to collagen fibrils in the equine tendon
- 2005
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Ingår i: Matrix Biology. - : Elsevier BV. - 1569-1802 .- 0945-053X. ; 24:5, s. 376-385
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Tidskriftsartikel (refereegranskat)abstract
- The structure and organisation of the extracellular matrix, and in particular the axial alignment of type I collagen fibrils, are essential for the tensile strength of tendons. The resident tenocytes synthesize and maintain the composition of the extracellular matrix, which changes with age and maturation. Other components of the extracellular matrix include less abundant collagen types II, III, V, VI, XII, proteoglycans and glycoproteins. Cartilage oligomeric matrix protein (COMP) is an abundant non-collagenous pentameric glycoprotein in the tendon, which can bind to collagen types I and II. The function of COMP in the tendon is not clear, but it may act as a catalyst in fibrillogenesis. Its concentration changes with age, maturation and load. The present study delineates the ultrastructural distribution of COMP and its correlation to collagen fibril thickness in different compartments in two flexor tendons from horses of different ages (foetus, 8 months, 3 years, 12 years). The immunolabeling for COMP was higher in the superficial digital flexor tendon compared with the deep digital flexor tendon and it increased with the age of the animal, with the highest concentration in the 3-year-olds. Fibril diameter differed between age groups and a more homogenous fibril population was found in the fetal tendons. A positive correlation between high COMP immunolabeling and the percentage of small fibrils (<60 nm) were present in the SDFT. COMP immunolabeling was enriched at the gap region of the collagen fibril. In situ hybridization revealed the strongest expression in tendons from the 3-year-old horses whereas there was no expression in foetal tendon.
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| 9. |
- Von Clarmann, T., et al.
(författare)
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A blind test retrieval experiment for infrared limb emission spectrometry
- 2003
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Ingår i: Journal of Geophysical Research - Atmospheres. - 2169-897X .- 2169-8996. ; 108:D23
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Tidskriftsartikel (refereegranskat)abstract
- The functionality and characteristics of six different data processors (i.e., retrieval codes in their actual software and hardware environment) for analysis of high-resolution limb emission infrared spectra recorded by the space-borne Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) have been validated by means of a blind test retrieval experiment based on synthetic spectra. For this purpose a self-consistent set of atmospheric state parameters, including pressure, temperature, vibrational temperatures, and abundances of trace gases and aerosols, has been generated and used as input for radiative transfer calculations for MIPAS measurement geometry and configuration. These spectra were convolved with the MIPAS field of view, spectrally degraded by the MIPAS instrument line shape, and, finally, superimposed with synthetic measurement noise. These synthetic MIPAS measurements were distributed among the participants of the project “Advanced MIPAS level-2 data analysis” (AMIL2DA), who performed temperature and species abundance profile retrievals by inverse radiative transfer calculations. While the retrieved profiles of atmospheric state parameters reflect some characteristics of the individual data processors, it was shown that all the data processors under investigation are capable of producing reliable results in the sense that deviations of retrieved results from the reference profiles are within the margin that is consistent with analytical error estimation.
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| 10. |
- Wells, T, et al.
(författare)
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Age-related changes in the composition, the molecular stoichiometry and the stability of proteoglycan aggregates extracted from human articular cartilage
- 2003
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Ingår i: Biochemical Journal. - 0264-6021. ; 370:1, s. 69-79
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Tidskriftsartikel (refereegranskat)abstract
- The heterogeneity of the components of proteoglycan aggregates, their stoichiometry within the aggregate and the aggregates' stability was investigated in normal human articular cartilage specimens (age-range newborn to 63 years). Proteoglycans were extracted from tissue by sequentially extracting them with PBS alone, PBS containing oligosaccharides of hyaluronan, and PBS containing solutions of increasing guanidinium chloride concentration (I M, 2 M, 3 M and 4 M). A high proportion of each of the components of the proteoglycan aggregate, i.e. uronic acid, sulphated glycosaminoglycan, hyaluronan binding domain of aggrecan (G1-domain), link protein (LP) and hyaluronan, was extracted from immature cartilage by PBS alone and PBS containing oligosaccharides of hyaluronan. This was in marked contrast to adult cartilage, which required high concentrations of guanidinium chloride for the efficient extraction of these components. The molar ratios of total G1-domain: LP and the G1-domain associated with aggrecan: LP also differed markedly between immature and mature cartilage and between each of the sequential extracts. The concentration of LP was less than that of the G1-domain in all extracts of cartilage from individuals over 13 years, but this was particularly noticeable in the I M guanidinium chloride extracts, and it was surmised that a deficiency in LP produces unstable aggregates in situ. The fragmentation of LP, which is known to occur with advancing age, did not influence the extractability of LP, and fragments were present in each of the sequential extracts. Therefore the generally accepted model of proteoglycan aggregation presented in the literature, which is mostly derived from analysis of immature animal cartilage, cannot be used to describe the structure and organization of aggregates in adult human articular cartilage, where a heterogeneous population of complexes exist that have varying degrees of stability.
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