bluuebunny/crossref_metadata_2025 huggingface dataset:
Arginase I Suppresses IL-12/IL-23p40–Driven Intestinal Inflammation during Acute Schistosomiasis
Authors: Herbert De’Broski R. , Orekov Tatyana , Roloson Amanda , Ilies Monica , Perkins Charles , O’Brien William , Cederbaum Stephen , Christianson David W. , Zimmermann Nives , Rothenberg Marc E. , Finkelman Fred D.
Published: May 2010

Alternatively activated macrophages prevent lethal intestinal pathology caused by worm ova in mice infected with the human parasite Schistosoma mansoni through mechanisms that are currently unclear. This study demonstrates that arginase I (Arg I), a major product of IL-4– and IL-13–induced alternatively activated macrophages, prevents cachexia, neutrophilia, and endotoxemia during acute schistosomiasis. Specifically, Arg I-positive macrophages promote TGF-β production and Foxp3 expression, suppress Ag-specific T cell proliferation, and limit Th17 differentiation. S. mansoni-infected Arg I-deficient bone marrow chimeras develop a marked accumulation of worm ova within the ileum but impaired fecal egg excretion compared with infected wild-type bone marrow chimeras. Worm ova accumulation in the intestines of Arg I-deficient bone marrow chimeras was associated with intestinal hemorrhage and production of molecules associated with classical macrophage activation (increased production of IL-6, NO, and IL-12/IL-23p40), but whereas inhibition of NO synthase-2 has marginal effects, IL-12/IL-23p40 neutralization abrogates both cachexia and intestinal inflammation and reduces the number of ova within the gut. Thus, macrophage-derived Arg I protects hosts against excessive tissue injury caused by worm eggs during acute schistosomiasis by suppressing IL-12/IL-23p40 production and maintaining the Treg/Th17 balance within the intestinal mucosa.
Human Eosinophils Recognize Endogenous Danger Signal Crystalline Uric Acid and Produce Proinflammatory Cytokines Mediated by Autocrine ATP
Authors: Kobayashi Takehito , Kouzaki Hideaki , Kita Hirohito
Published: May 2010

Eosinophils are multifunctional leukocytes involved in various inflammatory processes, as well as tissue remodeling and immunoregulation. During inflammation and infection, injured cells and damaged tissues release uric acid and monosodium urate (MSU) crystals as important endogenous danger signals. Uric acid is also implicated in the immunogenic effects of an authentic Th2 adjuvant, aluminum hydroxide. Eosinophils often localize at sites of Th2-type chronic inflammation; therefore, we hypothesized that eosinophils may react to endogenous danger signals. We found that human eosinophils migrate toward soluble uric acid and MSU crystals in a gradient-dependent manner. Eosinophils incubated with MSU crystals, but not those incubated with uric acid solution, produced elevated levels of IL-6 and IL-8/CXCL8. Other cytokines and chemokines, including IL-1β, IL-10, IL-17, IFN-γ, CCL2, CCL3, CCL4, TNF-α, G-CSF, GM-CSF, fibroblast growth factor, vascular endothelial growth factor, and TGF-β, were also produced by eosinophils incubated with MSU crystals. Eosinophils exposed to MSU crystals rapidly (i.e., within 1 min of exposure) released ATP into the extracellular milieu. Importantly, this autocrine ATP was necessary for eosinophils to produce cytokines in response to MSU crystals, and P2 nucleotide receptors, in particular P2Y2, are likely involved in this positive feedback loop. Finally, at higher concentrations, MSU crystals promoted P2R-dependent release of a granule protein (eosinophil-derived neurotoxin) and cell death. Thus, human eosinophils may respond to particulate damage-associated endogenous danger signals. These responses by eosinophils to tissue damage may explain the self-perpetuating nature of chronic inflammation in certain human diseases, such as asthma.
The E3 Ubiquitin Ligase RNF5 Targets Virus-Induced Signaling Adaptor for Ubiquitination and Degradation
Authors: Zhong Bo , Zhang Yu , Tan Bo , Liu Tian-Tian , Wang Yan-Yi , Shu Hong-Bing
Published: May 2010

Viral infection activates transcription factors, such as NF-κB and IFN regulatory factor 3, which collaborate to induce type I IFNs and elicit innate antiviral response. Virus-induced signaling adaptor (VISA) has been identified as a critical adaptor required for virus-triggered induction of type I IFNs. In this study, we showed that the E3 ubiquitin ligase RING-finger protein 5 (RNF5) interacted with VISA at mitochondria in a viral infection-dependent manner. Domain mapping experiments indicated that the C-terminal transmembrane domain of VISA was required for its interaction with RNF5. RNF5 targeted VISA at K362 and K461 for K48-linked ubiquitination and degradation after viral infection, whereas knockdown of RNF5 reversed virus-induced downregulation of VISA at the early phase. These findings suggest that RNF5-mediated ubiquitination and degradation of VISA is one of the mechanisms of the regulation of virus-triggered induction of type I IFNs and cellular antiviral response.
Membrane-Type I Matrix Metalloproteinase-Dependent Regulation of Rheumatoid Arthritis Synoviocyte Function
Authors: Sabeh Farideh , Fox David , Weiss Stephen J.
Published: May 2010

In rheumatoid arthritis, the coordinated expansion of the synoviocyte mass is coupled with a pathologic angiogenic response that leads to the destructive remodeling of articular as well as surrounding connective tissues. Although rheumatoid synoviocytes express a multiplicity of proteolytic enzymes, the primary effectors of cartilage, ligament, and tendon damage remain undefined. Herein, we demonstrate that human rheumatoid synoviocytes mobilize the membrane-anchored matrix metalloproteinase (MMP), membrane-type I MMP (MT1-MMP), to dissolve and invade type I and type II collagen-rich tissues. Though rheumatoid synoviocytes also express a series of secreted collagenases, these proteinases are ineffective in mediating collagenolytic activity in the presence of physiologic concentrations of plasma- or synovial fluid-derived antiproteinases. Furthermore, MT1-MMP not only directs the tissue-destructive properties of rheumatoid synoviocytes but also controls synoviocyte-initiated angiogenic responses in vivo. Together, these findings indentify MT1-MMP as a master regulator of the pathologic extracellular matrix remodeling that characterizes rheumatoid arthritis as well as the coupled angiogenic response that maintains the aggressive phenotype of the advancing pannus.
Vγ2Vδ2 T Cell Receptor Recognition of Prenyl Pyrophosphates Is Dependent on All CDRs
Authors: Wang Hong , Fang Zhimei , Morita Craig T.
Published: May 2010

γδ T cells differ from αβ T cells in the Ags they recognize and their functions in immunity. Although most αβ TCRs recognize peptides presented by MHC class I or II, human γδ T cells expressing Vγ2Vδ2 TCRs recognize nonpeptide prenyl pyrophosphates. To define the molecular basis for this recognition, the effect of mutations in the TCR CDR was assessed. Mutations in all CDR loops altered recognition and cover a large footprint. Unlike murine γδ TCR recognition of the MHC class Ib T22 protein, there was no CDR3δ motif required for recognition because only one residue is required. Instead, the length and sequence of CDR3γ was key. Although a prenyl pyrophosphate-binding site was defined by Lys109 in Jγ1.2 and Arg51 in CDR2δ, the area outlined by critical mutations is much larger. These results show that prenyl pyrophosphate recognition is primarily by germline-encoded regions of the γδ TCR, allowing a high proportion of Vγ2Vδ2 TCRs to respond. This underscores its parallels to innate immune receptors. Our results also provide strong evidence for the existence of an Ag-presenting molecule for prenyl pyrophosphates.
Association of Generalized Joint Hypermobility With a History of Glenohumeral Joint Instability
Authors: Cameron Kenneth L. , Duffey Michele L. , DeBerardino Thomas M. , Stoneman Paul D. , Jones Christopher J. , Owens Brett D.
Published: May 2010

Context:

Little is known about the relationship among sex, generalized joint hypermobility, and glenohumeral joint instability.

Objective:

To examine the relationship among sex, generalized joint hypermobility scores, and a history of glenohumeral joint instability within a young, physically active cohort and to describe the incidence of generalized joint hypermobility within this population.

Design:

Cross-sectional cohort study.

Setting:

United States Military Academy at West Point, New York.

Patients or Other Participants:

Of the 1311 members of the entering freshman class of 2010, 1050 (80%) agreed to participate.

Main Outcome Measure(s):

Generalized joint hypermobility was assessed using the Beighton Scale. A history of glenohumeral joint instability was identified via a baseline questionnaire.

Results:

Most participants (78%) had no signs of generalized joint hypermobility. Only 11 volunteers (1.5%) had Beighton Scale scores of 4 or greater. Logistic regression analysis revealed a relationship between generalized joint hypermobility and a history of glenohumeral joint instability (P  =  .023). When sex and race were controlled, those with a total Beighton Scale score of ≥2 were nearly 2.5 times as likely (odds ratio  =  2.48, 95% confidence interval  =  1.19, 5.20, P  =  .016) to have reported a history of glenohumeral joint instability. A relationship was observed between sex and nearly all individual Beighton Scale items. Although women had higher total Beighton Scale scores than men, sex (P  =  .658) and race (P  =  .410) were not related to a history of glenohumeral joint instability when other variables in the model were controlled.

Conclusions:

In these participants, generalized joint hypermobility and a history of glenohumeral joint instability were associated.
Case series: CT scan in cardiac arrest and imminent cardiogenic shock
Authors: Jana Manisha , Gamanagatti Shivanand Ramachandra , Kumar Atin
Published: May 2010

Imaging a patient having a cardiac arrest on the examination table is not a common occurrence. Altered hemodynamics resulting from pump failure causes stasis of blood in the dependent organs of the body, which is manifested on imaging by dependent contrast pooling and layering. Often a patient with imminent cardiogenic shock also shows a similar dependent contrast pooling and layering, which is a marker of the worsening clinical condition. We report the contrast-enhanced CT scan features in four cases, two of whom had cardiac arrest during imaging, while the other two developed cardiogenic shock soon after the examination. Dependent contrast pooling and layering were found in all of them, with faint or no opacification of the left cardiac chambers. Contrast pooling was noted in the dependent lumbar veins, hepatic veins, hepatic parenchyma, and the right renal vein, as well as in the dependent part of the IVC and the right heart chambers.
Case report: Stercoral sigmoid colonic perforation with fecal peritonitis
Authors: Sharma Monika , Agrawal Anjali
Published: May 2010

Chronic constipation can lead to fecal impaction. It can also rarely lead to catastrophic complications like perforation, colonic obstruction, and fecal peritonitis. We report a rare case of stercoral sigmoid colonic perforation with fecal peritonitis and pneumoperitoneum, which was diagnosed on preoperative CT scan.
Zygomatic air cell defect: A panoramic radiographic study of a south Indian population
Authors: Srikanth HS , Patil Karthikeya , Mahima VG
Published: May 2010

Aims: To determine the prevalence, patterns of occurrence and variations of zygomatic air cell defects (ZACDs) using panoramic radiographs. Methods and Materials: Dental panoramic radiographs of 600 outpatients were examined to evaluate the variations and characteristics of ZACDs. Results: ZACDs were identified in 15 subjects out of 600, giving an overall prevalence of 2.5%. Seven ZACDs were seen in males and eight in females. Among the 15 ZACDs, nine were unilateral and six were bilateral. Conclusion: The overall prevalence of ZACD is relatively low in south Indian population and careful radiographic evaluation is needed to detect these entities.
Migratory intralaryngeal thyroglossal duct cyst
Authors: Karlatti Pradeep D , Nagvekar Swapnil , Lekshmi TP , Kothari Abhay S
Published: May 2010

Intralaryngeal thyroglossal duct cysts are rare; a migrating one, rarer still. Such a case may be a cause for confusion and it is important to understand this entity and its typical findings.
Pictorial essay: Distal colostography
Authors: Rahalkar Mukund D , Rahalkar Anand M , Phadke Dilip M
Published: May 2010

Distal colostography (DC), also called distal colography or loopography, is an important step in the reparative management of anorectal malformations (ARMs) with imperforate anus, Hirschsprung′s disease (occasionally) and colonic atresia (rarely) in children and obstructive disorders of the distal colon (colitis with stricture, carcinoma or complicated diverticulosis) in adults. It serves to identify/confirm the type of ARM, presence/absence of fistulae, leakage from anastomoses, or patency of the distal colon. We present a pictorial essay of DC in a variety of cases.
Seasonal variations of concentrations and optical properties of water soluble HULIS collected in urban environments
Authors: Baduel C. , Voisin D. , Jaffrezo J.-L.
Published: May 2010

Abstract. Major contributors to the organic aerosol include water-soluble macromolecular compounds (e.g. HULISWS: Water Soluble Humic LIke Substances). The nature and sources of HULISWS are still largely unknown. This work is based on a monitoring in six different French cities performed during summer and winter seasons. HULISWS analysis was performed with a selective method of extraction complemented by carbon quantification. UV spectroscopy was also applied for their chemical characterisation. HULISWS carbon represent an important contribution to the organic aerosol mass in summer and winter, as it accounts for 12–22% of Organic Carbon and 34–40% of Water Soluble Organic Carbon. We found strong differences in the optical properties (specific absorbance at 250, 272, 280 nm and E2/E3 ratio) and therefore in the chemical structure between HULISWS from samples of summer- and wintertime. These differences highlight different processes responsible for emissions and formation of HULISWS according to the season, namely biomass burning in winter, and secondary processes in summer. Specific absorbance can also be considered as a rapid and useful indicator of the origin of HULISWS in urban environment.
Enhancement of marine cloud albedo via controlled sea spray injections: a global model study of the influence of emission rates, microphysics and transport
Authors: Korhonen H. , Carslaw K. S. , Romakkaniemi S.
Published: May 2010

Abstract. Modification of cloud albedo by controlled emission of sea spray particles into the atmosphere has been suggested as a possible geoengineering option to slow global warming. Previous global studies have imposed changes in cloud drop concentration in low level clouds to explore the radiative and climatic effects. Here, we use a global aerosol transport model to quantify how an imposed flux of sea spray particles affects the natural aerosol processes, the particle size distribution, and concentrations of cloud drops. We assume that the proposed fleet of vessels emits sea spray particles with a wind speed-dependent flux into four regions of persistent stratocumulus cloud off the western coasts of continents. The model results show that fractional changes in cloud drop number concentration (CDNC) vary substantially between the four regions because of differences in wind speed (which affects the spray efficiency of the vessels), transport and particle deposition rates, and because of variations in aerosols from natural and anthropogenic sources. Using spray emission rates comparable to those implied by previous studies we find that the predicted CDNC changes are very small (maximum 20%) and in one of the four regions even negative. The weak or negative effect is because the added particles suppress the in-cloud supersaturation and prevent existing aerosol particles from forming cloud drops. A scenario with five times higher emissions (considerably higher than previously assumed) increases CDNC on average by 45–163%, but median concentrations are still below the 375 cm−3 assumed in previous studies. An inadvertent effect of the spray emissions is that sulphur dioxide concentrations are suppressed by 1–2% in the seeded regions and sulphuric acid vapour by 64–68% due to chemical reactions on the additional salt particles. The impact of this suppression on existing aerosol is negligible in the model, but should be investigated further in the real environment so that inadvertent impacts can be excluded.
Carbon source/sink information provided by column CO2 measurements from the Orbiting Carbon Observatory
Authors: Baker D. F. , Bösch H. , Doney S. C. , O'Brien D. , Schimel D. S.
Published: May 2010

Abstract. We quantify how well column-integrated CO2 measurements from the Orbiting Carbon Observatory (OCO) should be able to constrain surface CO2 fluxes, given the presence of various error sources. We use variational data assimilation to optimize weekly fluxes at a 2°×5° resolution (lat/lon) using simulated data averaged across each model grid box overflight (typically every ~33 s). Grid-scale simulations of this sort have been carried out before for OCO using simplified assumptions for the measurement error. Here, we more accurately describe the OCO measurements in two ways. First, we use new estimates of the single-sounding retrieval uncertainty and averaging kernel, both computed as a function of surface type, solar zenith angle, aerosol optical depth, and pointing mode (nadir vs. glint). Second, we collapse the information content of all valid retrievals from each grid box crossing into an equivalent multi-sounding measurement uncertainty, factoring in both time/space error correlations and data rejection due to clouds and thick aerosols. Finally, we examine the impact of three types of systematic errors: measurement biases due to aerosols, transport errors, and mistuning errors caused by assuming incorrect statistics. When only random measurement errors are considered, both nadir- and glint-mode data give error reductions over the land of ~45% for the weekly fluxes, and ~65% for seasonal fluxes. Systematic errors reduce both the magnitude and spatial extent of these improvements by about a factor of two, however. Improvements nearly as large are achieved over the ocean using glint-mode data, but are degraded even more by the systematic errors. Our ability to identify and remove systematic errors in both the column retrievals and atmospheric assimilations will thus be critical for maximizing the usefulness of the OCO data.
Chemical characterisation of iron in dust and biomass burning aerosols during AMMA-SOP0/DABEX: implication for iron solubility
Authors: Paris R. , Desboeufs K. V. , Formenti P. , Nava S. , Chou C.
Published: May 2010

Abstract. The chemical composition and the soluble fraction were determined in aerosol samples collected during flights of AMMA-SOP0/DABEX campaign, which were conducted in the West African Sahel during dry season (2006). Two aerosol types are encountered in this period: dust particles (DUST) and biomass burning aerosol (BB). Chemical analysis and microscope observations showed that the iron (Fe) found in BB samples mainly originates from dust particles mostly internally mixed in the biomass burning layer. Chemical analyses of samples showed that the Fe solubility is lower in African dust samples than in biomass burning aerosols. Our data provide a first idea of the variability of iron dust solubility in the source region (0.1% and 3.4%). We found a relationship between iron solubility/clay content/source which partly confirms that the variability of iron solubility in this source region is related to the character and origin of the aerosols themselves. In the biomass burning samples, no relationship were found between Fe solubility and either the concentrations of acidic species (SO42−, NO3− or oxalate) or the content of carbon (TC, OC, BC). Therefore, we were unable to determine what processes are involved in this increase of iron solubility. In terms of supply of soluble Fe to oceanic ecosystems on a global scale, the higher solubility observed for Fe in biomass burning could imply an indirect source of Fe to marine ecosystems. But these aerosols are probably not significant because the Sahara is easily the dominant source of Fe to the Atlantic Ocean.
Particle formation and growth at five rural and urban sites
Authors: Jeong C.-H. , Evans G. J. , McGuire M. L. , Chang R. Y.-W. , Abbatt J. P. D. , Zeromskiene K. , Mozurkewich M. , Li S.-M. , Leaitch W. R.
Published: May 2010

Abstract. Ultrafine particle (UFP) number and size distributions were simultaneously measured at five urban and rural sites in Southern Ontario, Canada as part of the Border Air Quality and Meteorology Study (BAQS-Met 2007). Particle formation and growth events at these five sites were classified based on their strength and persistence as well as the variation in geometric mean diameter. Regional nucleation and growth events and local short-lived strong nucleation events were frequently observed at the near-border rural sites, upwind of industrial sources. Surprisingly, the particle number concentrations at one of these sites were higher than the concentrations at a downtown site in a major city, despite its high traffic density. Regional nucleation and growth events were favored at intense solar irradiance and less polluted cooler drier air. The most distinctive regional particle nucleation and growth event during the campaign was observed simultaneously at all five sites, which were up to 350 km apart. Although the ultrafine particle concentrations and size distributions generally were spatially heterogeneous across the region, a more uniform spatial distribution of UFP across the five areas was observed during this regional nucleation event. Thus, nucleation events can cover large regions, contributing to the burden of UFP in cities and potentially to the associated health impacts on urban populations. In addition, particle formation in southwestern Ontario appears to more often be related to anthropogenic gaseous emissions, although biogenic emissions may at times contribute. Local short-lived nucleation events at the near-border sites during this three-week campaign were associated with high SO2, which likely originated from US and Canadian industrial sources. These particle formation events may contribute to the production of cloud condensation nuclei, thus potentially influencing regional climate. Longer-term studies are needed to help resolve the relative contributions of anthropogenic and biogenic emissions to nucleation and growth in this region.
Diurnal variations of humidity and ice water content in the tropical upper troposphere
Authors: Eriksson P. , Rydberg B. , Johnston M. , Murtagh D. P. , Struthers H. , Ferrachat S. , Lohmann U.
Published: May 2010

Abstract. Observational results of diurnal variations of humidity from Odin-SMR and AURA-MLS, and cloud ice mass from Odin-SMR and CloudSat are presented for the first time. Comparisons show that the retrievals of humidity and cloud ice from these three satellite instruments are in good agreement. The retrieved data are combined from four almost evenly distributed times of the day allowing mean values, amplitudes and phases of the diurnal variations around 200 hPa to be estimated. This analysis is applied to six climatologically distinct regions, five located in the tropics and one over the subtropical northern Pacific Ocean. The strongest diurnal cycles are found over tropical land regions, where the amplitude is in the order of 6 %RHi for humidity and 50% for ice mass. The greatest ice mass is for these regions found during the afternoon, and the humidity maximum is observed to lag this peak by ~6 h. Over tropical ocean regions the variations are smaller and the maximum in both ice mass and humidity are found during the early morning. Observed results are compared with output from three climate models (ECHAM, EC-EARTH and CAM3). Direct measurement-model comparisons were not possible because the measured and modelled cloud ice masses represent different quantities. To make a meaningful comparison, the amount of snow had to be estimated from diagnostic parameters of the models. There is a high probability that the models underestimate the average ice mass (below the 1-σ uncertainty). The models show also clear deficiencies when it comes to amplitude and phase of the regional variations, but to a varying degree.
Quantifying uncertainty in projections of stratospheric ozone over the 21st century
Authors: Charlton-Perez A. J. , Hawkins E. , Eyring V. , Cionni I. , Bodeker G. E. , Kinnison D. E. , Akiyoshi H. , Frith S. M. , Garcia R. , Gettelman A. , Lamarque J. F. , Nakamura T. , Pawson S. , Yamashita Y. , Bekki S. , Braesicke P. , Chipperfield M. P. , Dhomse S. , Marchand M. , Mancini E. , Morgenstern O. , Pitari G. , Plummer D. , Pyle J. A. , Rozanov E. , Scinocca J. , Shibata K. , Shepherd T. G. , Tian W. , Waugh D. W.
Published: May 2010

Abstract. Future stratospheric ozone concentrations will be determined both by changes in the concentration of ozone depleting substances (ODSs) and by changes in stratospheric and tropospheric climate, including those caused by changes in anthropogenic greenhouse gases (GHGs). Since future economic development pathways and resultant emissions of GHGs are uncertain, anthropogenic climate change could be a significant source of uncertainty for future projections of stratospheric ozone. In this pilot study, using an "ensemble of opportunity" of chemistry-climate model (CCM) simulations, the contribution of scenario uncertainty from different plausible emissions pathways for ODSs and GHGs to future ozone projections is quantified relative to the contribution from model uncertainty and internal variability of the chemistry-climate system. For both the global, annual mean ozone concentration and for ozone in specific geographical regions, differences between CCMs are the dominant source of uncertainty for the first two-thirds of the 21st century, up-to and after the time when ozone concentrations return to 1980 values. In the last third of the 21st century, dependent upon the set of greenhouse gas scenarios used, scenario uncertainty can be the dominant contributor. This result suggests that investment in chemistry-climate modelling is likely to continue to refine projections of stratospheric ozone and estimates of the return of stratospheric ozone concentrations to pre-1980 levels.
Automatic cloud classification of whole sky images
Authors: Heinle A. , Macke A. , Srivastav A.
Published: May 2010

Abstract. The recently increasing development of whole sky imagers enables temporal and spatial high-resolution sky observations. One application already performed in most cases is the estimation of fractional sky cover. A distinction between different cloud types, however, is still in progress. Here, an automatic cloud classification algorithm is presented, based on a set of mainly statistical features describing the color as well as the texture of an image. The k-nearest-neighbour classifier is used due to its high performance in solving complex issues, simplicity of implementation and low computational complexity. Seven different sky conditions are distinguished: high thin clouds (cirrus and cirrostratus), high patched cumuliform clouds (cirrocumulus and altocumulus), stratocumulus clouds, low cumuliform clouds, thick clouds (cumulonimbus and nimbostratus), stratiform clouds and clear sky. Based on the Leave-One-Out Cross-Validation the algorithm achieves an accuracy of about 97%. In addition, a test run of random images is presented, still outperforming previous algorithms by yielding a success rate of about 75%, or up to 88% if only "serious" errors with respect to radiation impact are considered. Reasons for the decrement in accuracy are discussed, and ideas to further improve the classification results, especially in problematic cases, are investigated.
Accounting for surface reflectance anisotropy in satellite retrievals of tropospheric NO2
Authors: Zhou Y. , Brunner D. , Spurr R. J. D. , Boersma K. F. , Sneep M. , Popp C. , Buchmann B.
Published: May 2010

Abstract. Surface reflectance is a key parameter in satellite trace gas retrievals in the UV/visible range and in particular for the retrieval of nitrogen dioxide (NO2) vertical tropospheric columns (VTCs). Current operational retrievals rely on coarse-resolution reflectance data and do not account for the generally anisotropic properties of surface reflectance. Here we present a NO2 VTC retrieval that uses MODIS bi-directional reflectance distribution function (BRDF) data at high temporal (8 days) and spatial (1 km×1 km) resolution in combination with the LIDORT radiative transfer model to account for the dependence of surface reflectance on viewing and illumination geometry. The method was applied to two years of NO2 observations from the Ozone Monitoring Instrument (OMI) over Europe. Due to its wide swath, OMI is particularly sensitive to BRDF effects. Using representative BRDF parameters for various land surfaces, we found that in July (low solar zenith angles) and November (high solar zenith angles) and for typical viewing geometries of OMI, differences between MODIS black-sky albedos and surface bi-directional reflectances are of the order of 0–10% and 0–40%, respectively, depending on the position of the OMI pixel within the swath. In the retrieval, black-sky albedo was treated as a Lambertian (isotropic) reflectance, while for BRDF effects we used the kernel-based approach in the MODIS BRDF product. Air Mass Factors were computed using the LIDORT radiative transfer model based on these surface reflectance conditions. Differences in NO2 VTCs based on the Lambertian and BRDF approaches were found to be of the order of 0–3% in July and 0–20% in November with the extreme values found at large viewing angles. The much larger differences in November are partly due to higher solar zenith angles and partly to the choice of a priori NO2 profiles – the latter typically have more pronounced maxima in the boundary layer during the cold season. However, BRDF impacts vary considerably across Europe due to changes in land surface type and increasing solar zenith angles at higher latitude. Finally, we compare BRDF-based NO2 VTCs with those retrieved using the GOME/TOMS Lambertian equivalent reflectance (LER) data set. Our results indicate that the specific choice of albedo data set is even more important than accounting for surface BRDF effects, and this again demonstrates the strong requirement for more accurate surface reflectance data sets.
Carbon fluxes in natural plankton communities under elevated CO2levels: a stable isotope labeling study
Authors: de Kluijver A. , Soetaert K. , Schulz K. G. , Riebesell U. , Bellerby R. G. J. , Middelburg J. J.
Published: May 2010

Abstract. The potential impact of rising carbon dioxide (CO2) on carbon fluxes in natural plankton communities was investigated during the 2005 PeECE III mesocosm study in Bergen, Norway. Triplicate mesocosms, in which a phytoplankton bloom was induced by nutrient addition, were incubated with 1×(~350 μatm), 2×(~700 μatm), and 3× present day CO2(~1050 μatm) levels for 3 weeks. 13C labeled bicarbonate was added to all mesocosms to follow the transfer of carbon from dissolved inorganic carbon (DIC) into phytoplankton and subsequently heterotrophic bacteria, zooplankton, and settling particles. Isotope ratios of polar lipid fatty acids (PLFA) were used to infer the biomass and production of phytoplankton and bacteria. Phytoplankton PLFA were enriched within one day after label addition, while it took another 3 days before bacteria showed substantial enrichment. Group-specific primary production measurements revealed that coccolithophores grew faster than green algae and diatoms. Elevated CO2 had a significant positive effect on post-bloom biomass of green algae, diatoms, and bacteria. A simple model based on measured isotope ratios of phytoplankton and bacteria revealed that CO2 had no significant effect on the carbon transfer efficiency from phytoplankton to bacteria. There was no indication of enhanced settling based on isotope mixing models during the phytoplankton bloom. Our results suggest that CO2 effects are most pronounced in the post-bloom phase, under nutrient limitation.
Analysis of the energy balance closure over a FLUXNET boreal forest in Finland
Authors: Sánchez J. M. , Caselles V. , Rubio E. M.
Published: May 2010

Abstract. The imbalance in the surface energy budget, when using eddy-covariance techniques to measure turbulent fluxes, is still an unresolved problem. Important progresses have been reported in recent years identifying potential reasons for this lack of energy balance closure. In this paper we focus on the data collected in a FLUXNET boreal forest site in Sodankylä, Finland. Using one month half-hourly data, an average Energy Balance Ratio (EBR) of 0.72 is obtained. The inclusion of the heat storage terms in the energy budget yields an improvement of about 6% in the total closure. The sensitivity of the energy balance closure to the turbulence intensity is analysed in terms of the friction velocity, and atmospheric stability/instability conditions. Significant better closure is obtained for high values of the friction velocity and unstable conditions. The mismatch in variable footprints for different fluxes is checked by analysing the dependence of the closure on wind direction. The inhomogeneities of the emplacement surrounding the flux tower induce a critical decrease in the EBR of up to 30% for specific wind directions. After filtering all unfavourable conditions, EBR=0.94. This is a reasonable good result for the energy balance closure. However there is still a 6% of the available energy unaccounted. Part of this remaining imbalance could be justified as the impossibility of the 30 min averaging time to capture the low frequency flux contributions, since the closure is improved by a 5% when the averaging time is expanded to 2 h.
Monitoring ice shelf velocities from repeat MODIS and Landsat data – a method study on the Larsen C ice shelf, Antarctic Peninsula, and 10 other ice shelves around Antarctica
Authors: Haug T. , Kääb A. , Skvarca P.
Published: May 2010

Abstract. We investigate the velocity field of the Larsen C ice shelf, Antarctic Peninsula, over the periods 2002–2006 and 2006–2009 based on repeat optical satellite data. The velocity field of the entire ice shelf is measured using repeat low resolution MODIS data (250 m spatial resolution). The measurements are validated for two ice shelf sections against repeat medium resolution Landsat 7 ETM + pan data (15 m spatial resolution). Horizontal surface velocities are obtained through image matching using both orientation correlation operated in the frequency domain and normalized crosscorrelation operated in the spatial domain, and the two methods compared. The uncertainty in the displacement measurements turns out to be about one fourth of the pixel size for the MODIS derived data, and about one pixel for the Landsat derived data. The difference between MODIS and Landsat based speeds is −15.4 m a−1 and 13.0 m a−1, respectively, for the first period for the two different validation sections on the ice shelf, and −26.7 m a−1 and 27.9 m a−1 for the second period for the same sections. This leads us to conclude that repeat MODIS images are well suited to measure ice shelf velocity fields and monitor their changes over time. Orientation correlation seems better suited for this purpose because it produces fewer mismatches, is able to match images with regular noise and data voids, and is faster. Since it can match images with regular data voids it is possible to match Landsat 7 ETM+ images even after the 2003 failure of the Scan Line Corrector (SLC off) that leaves significant image stripes with no data. Image matching based on the original 12-bit radiometric resolution MODIS data produced slightly better results than using the 8-bit version of the same images. Streamline interpolation from the obtained surface velocity field on Larsen C indicates ice travel times of up to 450 to 550 years between the inland boundary and the ice shelf edge. In a second step of the study we test our method successfully on 10 other ice shelves around Antarctica demonstrating that the approach presented could in fact be used for large scale monitoring of ice shelf dynamics.
Assessment of Enteral Bacteria
Authors: Menozzi Alessandro , Ossiprandi Maria Cristina
Published: May 2010

The disruption of intestinal barrier leads to the penetration of noxious luminal compounds into the gut wall, causing further damage. This unit describes the assessment of enteric bacteria translocation into the intestinal wall of rats, an established method for the evaluation of bowel damage to the mucosal epithelial barrier. The Basic Protocol provided in the present unit describes collection and preparation of small intestine sample, performing of sample serial dilutions for bacterial culture, performing of the culture of aerobic and anaerobic bacteria on petri dishes, incubation of the cultured plates, and counting of bacterial colonies. The Support Protocols describes the procedures for the preparation of petri dishes for the culture, using different employable media for aerobes or anaerobes. The Alternate Protocol describes the use of the “inclusion method,” suitable for the culture of anaerobic bacteria. Curr. Protoc. Toxicol. 44:21.3.1‐21.3.11. © 2010 by John Wiley & Sons, Inc.
Assessment of Ischemic Vascular Damage
Authors: Nosál'ová Viera , Sotníková Ruzena
Published: May 2010

This protocol describes a model convenient for acute experiments in anesthetized rats, performed by selective occlusion of the superior mesenteric artery. Such a model provides a means for assessing the role played by various pathophysiological mechanisms in the development of intestinal ischemic injury. It is especially suitable for studying different treatments, mainly pharmacological ones, to help cope with this problem in clinical practice. In the form of support protocols, this unit includes functional vascular and chemiluminescence studies, determination of vascular permeability and myeloperoxidase activity, transit time, and mortality. Curr. Protoc. Toxicol. 44:21.4.1‐21.4.21. © 2010 by John Wiley & Sons, Inc.
Growth and Laboratory Maintenance of Vibrio cholerae
Authors: Martinez Raquel M. , Megli Christina J. , Taylor Ronald K.
Published: May 2010

Vibrio cholerae is a Gram‐negative enteric pathogen. This unit includes protocols for the growth and maintenance of V. cholerae in the laboratory. Curr. Protoc. Microbiol. 17:6A.1.1‐6A.1.7. © 2010 by John Wiley & Sons, Inc.
Growth and Maintenance of Chick Embryo Fibroblasts (CEF)
Authors: Hernandez Raquel , Brown Dennis T.
Published: May 2010

Primary cultures of chick embryo fibroblasts (CEF) are widely used for the cultivation of viruses. Protocols for the growth and maintenance of CEF cells in the laboratory are provided. Curr. Protoc. Microbiol. 17:A.4I.1‐A.4I.8. © 2010 by John Wiley & Sons, Inc.
Modern India and the vitamin D dilemma: Evidence for the need of a national food fortification program
Authors: Babu Uma S. , Calvo Mona S.
Published: May 2010

India is located between 8.4 and 37.6°N latitude with the majority of its population living in regions experiencing ample sunlight throughout the year. Historically, Indians obtained most of their vitamin D through adequate sun exposure; however, darker skin pigmentation and the changes which have accompanied India's modernization, including increased hours spent working indoors and pollution, limit sun exposure for many. Inadequate sun exposure results in reduced vitamin D synthesis and ultimately poor vitamin D status if not compensated by dietary intake. Dietary vitamin D intake is very low in India because of low consumption of vitamin D rich foods, absence of fortification and low use of supplements. All these factors contribute to poor vitamin D status as measured by low circulating levels of 25‐hydroxy vitamin D. Our review searches the published literature specific to India for evidence that would confirm the need to fortify food staples with vitamin D or stimulate public health policies for vitamin D supplementation and dietary guidelines tailored to the Indian diet. This review documents findings of widespread vitamin D deficiency in Indian populations in higher and lower socioeconomic strata, in all age groups, in both genders and people in various professions. Moreover, poor vitamin D status in India is accompanied by increased bone disorders including osteoporosis, osteomalacia in adults and rickets and other bone deformities in children. Without a concerted national effort to screen for vitamin D status, to implement policies or guidelines for vitamin D fortification and/or supplementation and to re‐assess recommended dietary intake guidelines, dramatic increase in the number of bone disorders and other diseases may lie ahead.
Correcting poor vitamin D status: Do older adults need higher repletion doses of vitamin D3 than younger adults?
Authors: Whiting Susan J. , Calvo Mona S.
Published: May 2010

We conducted an examination of recent studies to determine whether older adults (≥65 years) need higher levels of supplementary vitamin D than young adults when attempting to replete vitamin D status in deficient subjects, i.e. those with levels of 25‐hydroxyvitamin D less than 75 nmol/L. As data on repletion with vitamin D2 have recently been published, we restricted our discussion to the use of vitamin D3 from dietary supplements, prescriptions for large oral doses, and bolus dosing or injections. Most published dosing regimens failed to achieve 75 nmol/L in most all subjects, whether young adults (<65 years) or older adults (≥65 years). Whether as daily or bolus oral supplementation, elderly subjects appeared to need more vitamin D3 compared with younger adults, however, baseline levels, endpoints, study duration, compliance, and other factors were different among studies. To ensure most subjects are replete in vitamin D, a daily dose of more than 50 μg (2000 IU) in younger and 125 μg (5000 IU) is required. Other strategies including bolus and loading doses are described. No study reported adverse effects of using oral intakes about the current upper level of 50 μg (2000 IU).
Differential response of four human livers to modulation of phase II enzyme systems by the chemopreventive phytochemical phenethyl isothiocyanate
Authors: Konsue Nattaya , Ioannides Costas
Published: May 2010

A principal mechanism of the chemopreventive activity of isothiocyanates is detoxification of the genotoxic metabolites of chemical carcinogens through up‐regulation of enzymes such as quinone reductase and the glutathione‐S‐transferases. In this study we report, for the first time, the potential of the aromatic isothiocyanate, phenethyl isothiocyanate (PEITC) to modulate these enzymes in human liver from four donors, in comparison with rat liver. Precision‐cut human and rat liver slices were incubated with PEITC at concentrations that can be achieved in plasma following dietary intake. Glutathione‐S‐transferase activity increased in rat slices whereas in human slices activity rose only in three of the four donors. At the protein level, a marked rise in GSTα was seen in one of the human donors whereas much less pronounced elevation was noted in the other three. Quinone reductase activity doubled in rat liver slices incubated with PEITC, and was accompanied by an increase in protein expression. Only in one of the human donors was activity and expression of quinone reductase elevated. These studies illustrate that there are very pronounced differences in the response of human liver to PEITC, indicating that the chemopreventive effect of isothiocyanates may not be manifested in all individuals.
Vitamin D supplementation in a nursing home population
Authors: Schwalfenberg Gerry K. , Genuis Stephen J.
Published: May 2010

To determine if daily supplementation of 2000 IU of vitamin D3 is able to normalize the 25(OH)D3 status in a nursing home population, a group particularly prone to Vitamin D insufficiency. A chart review was performed to retrospectively determine the 25(OH)D3 level in each nursing home patient (N=68) who had received a minimum of 5 months of daily 2000 IU vitamin D3 supplementation. 94.1% of nursing home residents had a 25(OH)D3 level in excess of 80 nmol/L after a minimum of 5 months of daily 2,000 IU vitamin D3 supplementation. No residents had 25(OH)D3 levels in a toxic range. In order to improve health and well‐being and to preclude preventable morbidity and mortality associated with 25(OH)D3 insufficiency, all nursing home patients without contraindication should be routinely supplemented with (at minimum) 2000 IU of vitamin D3 on a daily basis.
The red wine extract‐induced activation of endothelial nitric oxide synthase is mediated by a great variety of polyphenolic compounds
Authors: Auger Cyril , Chaabi Mehdi , Anselm Eric , Lobstein Annelise , Schini‐Kerth Valérie B.
Published: May 2010

Phenolic extracts from red wine (RWPs) have been shown to induce nitric oxide (NO)‐mediated vasoprotective effects, mainly by causing the PI3‐kinase/Akt‐dependent activation of endothelial NO synthase (eNOS). RWPs contain several hundreds of phenolic compounds. The aim of the present study was to identify red wine phenolic compounds capable of activating eNOS in endothelial cells using multi‐step fractionation. The red wine phenolic extract was fractionated using Sephadex LH‐20 and preparative RP‐HPLC approaches. The ability of a fraction to activate eNOS was assessed by determining the phosphorylation level of Akt and eNOS by Western blot analysis, and NO formation by electron spin resonance spectroscopy. Tentative identification of phenolic compounds in fractions was performed by MALDI‐TOF and HPLC‐MS techniques. Separation of RWPs by Sephadex LH‐20 generated nine fractions (fractions A to I), of which fractions F, G, H and I caused significant eNOS activation. Fraction F was then subjected to semi‐preparative RP‐HPLC to generate ten subfractions (subfraction SF1 to SF10), all of which caused eNOS activation. The active fractions and subfractions contained mainly procyanidins and anthocyanins. Isolation of phenolic compounds from SF9 by semi‐preparative RP‐HLPC lead to the identification of petunidin‐O‐coumaroyl‐glucoside as a potent activator of eNOS.
CAS kontra Google
Authors: Marx Werner , Schier Hermann
Published: May 2010

Allzu leicht gerät bei der Euphorie über die Informationsquellen im Internet in Vergessenheit, dass auch strukturierte Information angeboten wird und unabdingbar für die Suche nach Literatur oder Fakten sein kann. Doch welches Informationssystem (oder welche Kombination von Systemen) leistet die besten Dienste? Was entscheidet über Erfolg oder Misserfolg einer Recherche?
Im Auftrag Ihrer Qualität
Authors: Liebich Gisela , Pohl Barbara
Published: May 2010

Unternehmen greifen für die Qualitätssicherung häufig auf externe Berater und Laboratorien zurück. Sie arbeiten direkt in den Labors des Kunden oder führen die notwendigen chemischen Analysen außerhalb des auftraggebenden Betriebs durch.