Platelet 1958 Volume

The basic single-angle interval light-scattering method caimot accurately measure individual red blood cell or platelet volumes, but it can provide MCV and MPV. Red cells are bi-concave disks, and platelets ate rod to disk shaped Scattering intensities depend on the orientation in the flow cell. 

Overall platelet dimensions of mineral aurichalcite did not appear to change during calcination, but became polycrystalline and porous. By dark field Imaging in the TEM, the ZnO particles were observed to be uniformly and highly dispersed. The porosity can be accounted for by the approximately threefold increase in density of Zn atoms upon decomposition of aurichalcite to ZnO. For this density change to occur with a constant overall platelet volume, pores must form. 

GP 2] [R 2] The definition of space-time yield in a micro reactor depends on the definition of the reactor volume . Owing to the large amoimt of construction material relative to the reaction channels and the neglect of some reactor parts ( abstraction to the real reaction zone ), several more or less useful definitions can be made. In the following, two definitions concerning the time yield divided by the pure reaction channel volume and the platelet volume were used. 

MPV Mean platelet volume PA Physician Assistant posteroanterior pulmonary... 

Since no consistent differences in serotonergic catabolism or metabolism have been identified in autism, yet a substantial proportion of autistic people have increased concentrations of platelet serotonin, attention has turned to the platelets themselves. Platelet irregularities may include increased platelet exposure, increased platelet volume or enhanced platelet uptake and storage, of serotonin. By measuring the concentration of plasma free levels of serotonin, it is possible to assess whether the platelet is exposed to elevated lev-... 

Mean platelet volume increase. Hot water extract of the seed, administered orally to adults at a dose of five cups per day, produced weak activity ". 

Peters, L. L., Zhang, W., Lambert, A. J., Brugnara, C., Churchill, G. A. and Platt, O. S. (2005) Quantitative trait loci for baseline white blood cell count, platelet count, and mean platelet volume. Mamm Genome 16, 749-763. 

MCV, mean corpuscular volume MPV, mean platelet volume ... 

Ranganath LR, Christolides J, and Semple MJ. (1996). Increased mean platelet volume after oestrogen replacement therapy. Annals Clin. Biochem. 33 ( Pt 6), 555-560. 

Cats have large platelets with a mean platelet volume of 15.1 fl. These large platelets overlap in size with erythrocytes matog automated platelet coimts subject to error (Tschopp 1970). Additionally, platelet aggregates are frequently encountered in blood samples collected for routine hematologic tests. 

Whenever pseudothrombocytopenia is suspected, for example in the case of unexpected thrombocytopenia without signs of bleeding, the diagnosis can be confirmed by finding normal platelet counts immediately after drawing the blood specimen or by examination of a blood smear. When serial counts are made, the number of platelets falls linearly with time. Pseudothrombocytopenia is usually associated with a normal mean platelet volume, whereas true thrombocytopenia is associated with a reduced mean platelet volume (28). 

Figure 20.2. Effects of platelet orientation relative to the direction of deformation, predicted by using the model of Brune and Bicerano [11]. The orientation angle is defined as the angle between the symmetry axis of the platelets and the direction of deformation, so that it is 90° if the platelets are aligned perfectly along the direction of deformation while it is 0° if the platelets are aligned completely perpendicular to the direction of deformation. The curves are labeled by the platelet aspect ratio Af. The platelet volume fraction was =0.025, the platelets were assumed to have a Young s modulus of 100 times that of the matrix, and a Poisson s ratio of 0.4 was assumed for both the matrix polymer and the platelets in these calculations.

The HCP model implies that in diluted systems ( < 0.005, where exfoliated clay platelets may freely rotate), individual HCPs are dispersed in a polymeric matrix and values of the interaction parameters are constant. As the concentration increases, the domains of reduced mobility around HCPs begin to overlap, macromolecules with bulk properties disappear, and the interactions change with clay content. Above the encompassed clay platelet volume fraction, rot = Q.99 p 0.005, there is a second critical concentration, Wmax 3.6 wt% or (/>max 0.015, at which the clay platelets with adsorbed solidified organic phase begin to overlap. Due to platelet crowding, CPNC approaching this concentration forms stacks thus, the assumption that individual exfoliated platelets are present is no longer valid. 

FIGURE 6. The dependence of the mechanical properties of alumina platelet reinforced borosilicate glass matrix composites on the platelet volume fraction (a) Young s modulus, (b) fracture strength and (c) fracture toughness... 

Volume of the sample (volume of dissolved polymer in case of solutions) Sum of cold filter plugging point (CFPP) results Difference between the aggregated and free polymer volume fractions Contrast between the solvent and the platelet Polymer scattering contrast Contrast between the solvent and the rod Wax scattering contrast Volume fraction of platelets Volume fraction of rods... 

Whole blood is seldom used ia modem blood transfusion. Blood is separated into its components. Transfusion therapy optimizes the use of the blood components, using each for a specific need. Red cell concentrates are used for patients needing oxygen transport, platelets are used for hemostasis, and plasma is used as a volume expander or a source of proteins needed for clotting of the blood. 

The formed elements consist primarily of red blood cells, ie, erythrocytes. Less than 1 /600 of the total volume of the formed elements is composed of white blood cells, ie, leukocytes, and less than 1/800 are platelets, ie, thrombocytes. Table 1 gives the typical constitution of human blood. 

Fig. 2. Histograms representing (a), the frequency of occurrence of platelets (PLT) and red blood cells (RBC) and illustrating coincidence where SL is low angle scatter, 2°C—3° and SH is high angle scatter, 5°C—15° (b), the volume of RBC, from 0 to 200 fL (c), the hemoglobin (HGB) concentration from 0 to...

Because the cells can intermpt the optical path in random orientations, individual scattering intensities are not proportional to cell volume. However, because thousands of cells of each type pass through the flow cell, the effects of orientation can be averaged To a first approximation HCT and platelet crit (PCT), the percentage of blood sample volume occupied by platelets, is proportional to the sums of the scattering intensities of the ted cells and platelets, respectively. MCV can be computed from HCT and RBC, whereas MPV can be computed from PCT and PLT. The accuracy of MCV deterrnined by this method is tied to the RBC accuracy, as is the case for the manual MCV method. Ortho Instmments Corporation s ELT-8 uses these counting and sizing methods. 

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