1,254 research outputs found
Transfusion Problems in Hemolytic Anemias
In this presentation I have attempted to present some of the transfusion problems that face the Blood Bank and the physician treating the patient. I have briefly discussed methods of recognizing the complicating factors, interpretation of their clinical significance, and the proper hemotherapeutic management of such cases. Finally, I hope that this presentation is a convincing thesis for a better understanding of the Blood Bank and its problems, since the patient\u27s welfare is better served when there is a rapport between the clinician and the Blood Bank staff
Paleoserologic Studies: ABO and Histocompatibility Antigens in Mummified American Indians
The first genetic polymorphism to be described in man was the ABO blood group system. Ths system proved to be present as a membrane antigen of the cells of almost all organs of the body. In this it not only stimulates histocompatibility antigens but also helps to determine ABO compatibility between organ recipients and their donors. The presence of the ABH and HL-A antigens in tissues and their stability on storage allows typing mummified bodies despite the passage of thousands of years
HAA (HB Ag) Evaluation-State of the Art
In conclusion, this study supports the claim that the RIA is the most sensitive of all assay methods for detection of HB Ag in use today. Because of the inability to verify the presence of HB Ag in those sera positive by RIA alone, however, this claim must be taken only at face value. Further studies are needed to confirm the specificity of these positive reactions
Determination of Leukoagglutinin Specificity by In Vivo and In Vitro Studies
Results of testing sera from normal individuals and pathological patients, using a bromelin technique for the detection of leukoagglutinins, are reported. These results, supported further by an in vivo experiment, suggested that the phenomenon of leukoagglutination is immunologic in nature and that leukoagglutinins may be the cause of some febrile transfusion reactions. These are specifically directed against leukocytes, and do not involve the red cell series. Furthermore, the antigen (or antigens) is probably present in both the granulocytes and the mononuclear leukocytes. Anti-platelet antibodies could be presumed to be the cause of thrombocytopenia
Impact of deep convection and dehydration on bromine loading in the upper troposphere and lower stratosphere
Stratospheric bromine loading due to very short-lived substances is investigated with a three-dimensional chemical transport model over a period of 21 years using meteorological input data from the European Centre for Medium-Range Weather Forecasts ERA-Interim reanalysis from 1989 to the end of 2009. Within this framework we analyze the impact of dehydration and deep convection on the amount of stratospheric bromine using an idealized and a detailed full chemistry approach. We model the two most important brominated short-lived substances, bromoform (CHBr<sub>3</sub>) and dibromomethane (CH<sub>2</sub>Br<sub>2</sub>), assuming a uniform convective detrainment mixing ratio of 1 part per trillion by volume (pptv) for both species. The contribution of very short-lived substances to stratospheric bromine varies drastically with the applied dehydration mechanism and the associated scavenging of soluble species ranging from 3.4 pptv in the idealized setup up to 5 pptv using the full chemistry scheme. In the latter case virtually the entire amount of bromine originating from very short-lived source gases is able to reach the stratosphere thus rendering the impact of dehydration and scavenging on inorganic bromine in the tropopause insignificant. Furthermore, our long-term calculations show that the mixing ratios of very short-lived substances are strongly correlated to convective activity, i.e. intensified convection leads to higher amounts of very short-lived substances in the upper troposphere/lower stratosphere especially under extreme conditions like El Niño seasons. However, this does not apply to the inorganic brominated product gases whose concentrations are anti-correlated to convective activity mainly due to convective dilution and possible scavenging, depending on the applied approach
Status of fish consumption per capita of Tehran citizens
Status of fish consumption was analyzed by completing the 295 questionnaires in all 22 metropolitan regions of Tehran from different households in 2008. After reviewing the descriptive and statistics analysis along with the non-parametric statistics, the fish consumption per capita was extracted through formulas. The average and mode of purchasing of each household occurs 11 times per year with 5.1 Kg in each time . Considering the higher fish consumption growth rate in Iran, the sequence of interest in all kinds of protein is as follows: poultry, mutton, beef, Trout, wild fishes and Chinese carps. The highest interest of households to buy fish more than other protein resources is due to the nutrient value of it. An average of 33.2% purchasing is dedicated to the farmed fish. 59% of purchasers are interested to buy packed up fish products and pay attention to the label of nutrient values on the product package. Fish consumption per capita is 13.3 Kg, which is divided to 6.4 kg for farmed fishes, 5.8 Kg for wild fishes and 1.1 Kg for canned fish. The higher consumption per capita of Tehran citizens in comparison with other people from other cities, who are living in Tehran, is because of their tendency and freshness of farmed fishes. In contrast, the consumption of canned and wild fishes among people of littoral regions who live in Tehran is higher than others
Cluster-based ensemble means for climate model intercomparison
Clustering – the automated grouping of similar data – can provide powerful and unique insight into large and complex data sets, in a fast and computationally efficient manner. While clustering has been used in a variety of fields (from medical image processing to economics), its application within atmospheric science has been fairly limited to date, and the potential benefits of the application of advanced clustering techniques to climate data (both model output and observations) has yet to be fully realised. In this paper, we explore the specific application of clustering to a multi-model climate ensemble. We hypothesise that clustering techniques can provide (a) a flexible, data-driven method of testing model–observation agreement and (b) a mechanism with which to identify model development priorities. We focus our analysis on chemistry–climate model (CCM) output of tropospheric ozone – an important greenhouse gas – from the recent Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). Tropospheric column ozone from the ACCMIP ensemble was clustered using the Data Density based Clustering (DDC) algorithm. We find that a multi-model mean (MMM) calculated using members of the most-populous cluster identified at each location offers a reduction of up to ∼ 20 % in the global absolute mean bias between the MMM and an observed satellite-based tropospheric ozone climatology, with respect to a simple, all-model MMM. On a spatial basis, the bias is reduced at ∼ 62 % of all locations, with the largest bias reductions occurring in the Northern Hemisphere – where ozone concentrations are relatively large. However, the bias is unchanged at 9 % of all locations and increases at 29 %, particularly in the Southern Hemisphere. The latter demonstrates that although cluster-based subsampling acts to remove outlier model data, such data may in fact be closer to observed values in some locations. We further demonstrate that clustering can provide a viable and useful framework in which to assess and visualise model spread, offering insight into geographical areas of agreement among models and a measure of diversity across an ensemble. Finally, we discuss caveats of the clustering techniques and note that while we have focused on tropospheric ozone, the principles underlying the cluster-based MMMs are applicable to other prognostic variables from climate models
Distribution of glycine/GABA neurons in the ventromedial medulla with descending spinal projections and evidence for an ascending glycine/GABA projection
The ventromedial medulla (VM), subdivided in a rostral (RVM) and a caudal (CVM) part, has a powerful influence on the spinal cord. In this study, we have identified the distribution of glycine and GABA containing neurons in the VM with projections to the cervical spinal cord, the lumbar dorsal horn, and the lumbar ventral horn. For this purpose, we have combined retrograde tracing using fluorescent microspheres with fluorescent in situ hybridization (FISH) for glycine transporter 2 (GlyT2) and GAD67 mRNAs to identify glycinergic and/or GABAergic (Gly/GABA) neurons. Since the results obtained with FISH for GlyT2, GAD67, or GlyT2+GAD67 mRNAs were not significantly different, we concluded that glycine and GAB
Modelling marine emissions and atmospheric distributions of halocarbons and dimethyl sulfide: the influence of prescribed water concentration vs. prescribed emissions
Marine-produced short-lived trace gases such as dibromomethane (CH2Br2), bromoform (CHBr3), methyliodide (CH3I) and dimethyl sulfide (DMS) significantly impact tropospheric and stratospheric chemistry. Describing their marine emissions in atmospheric chemistry models as accurately as possible is necessary to quantify their impact on ozone depletion and Earth's radiative budget. So far, marine emissions of trace gases have mainly been prescribed from emission climatologies, thus lacking the interaction between the actual state of the atmosphere and the ocean. Here we present simulations with the chemistry climate model EMAC (ECHAM5/MESSy Atmospheric Chemistry) with online calculation of emissions based on surface water concentrations, in contrast to directly prescribed emissions. Considering the actual state of the model atmosphere results in a concentration gradient consistent with model real-time conditions at the ocean surface and in the atmosphere, which determine the direction and magnitude of the computed flux. This method has a number of conceptual and practical benefits, as the modelled emission can respond consistently to changes in sea surface temperature, surface wind speed, sea ice cover and especially atmospheric mixing ratio. This online calculation could enhance, dampen or even invert the fluxes (i.e. deposition instead of emissions) of very short-lived substances (VSLS). We show that differences between prescribing emissions and prescribing concentrations (−28 % for CH2Br2 to +11 % for CHBr3) result mainly from consideration of the actual, time-varying state of the atmosphere. The absolute magnitude of the differences depends mainly on the surface ocean saturation of each particular gas. Comparison to observations from aircraft, ships and ground stations reveals that computing the air–sea flux interactively leads in most of the cases to more accurate atmospheric mixing ratios in the model compared to the computation from prescribed emissions. Calculating emissions online also enables effective testing of different air–sea transfer velocity (k) parameterizations, which was performed here for eight different parameterizations. The testing of these different k values is of special interest for DMS, as recently published parameterizations derived by direct flux measurements using eddy covariance measurements suggest decreasing k values at high wind speeds or a linear relationship with wind speed. Implementing these parameterizations reduces discrepancies in modelled DMS atmospheric mixing ratios and observations by a factor of 1.5 compared to parameterizations with a quadratic or cubic relationship to wind spee
Revisiting the hemispheric asymmetry in mid-latitude ozone changes following the Mount Pinatubo eruption: A 3-D model study
Following the eruption of Mt. Pinatubo, satellite and in-situ measurements showed a large enhancement in stratospheric aerosol in both hemispheres, but significant mid-latitude column O3 depletion was observed only in the north. We use a three-dimensional chemical transport model to determine the mechanisms behind this hemispheric asymmetry. The model, forced by European Centre for Medium-Range Weather Forecasts ERA-Interim reanalyses and updated aerosol surface area density, successfully simulates observed large column NO2 decreases and the different extents of ozone depletion in the two hemispheres. The chemical ozone loss is similar in the northern (NH) and southern hemispheres (SH), but the contrasting role of dynamics increases the depletion in the NH and decreases it in the SH. The relevant SH dynamics are not captured as well by earlier ERA-40 reanalyses. Overall the smaller SH column O3 depletion can be attributed to dynamical variability and smaller SH background lower stratosphere O3 concentrations
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