Environmental and mineralogical studies on the stream sediments of Baltim-El Burullus coastal plain, North Delta, Egypt.

This work is mainly concerned with the effect of anthropogenic activities and natural radioactivity due to the presence of highly radioactive black sand spots, factory construction, and shipping, in addition to other activities like agriculture on human beings. Forty samples were collected along Baltim-El Burullus coastal plain to detect the effect of these problems and determine the suggested solutions. The black sand of the Baltim-El Burullus coastal plain exhibits a considerable amount of economically heavy minerals, their ratio relative to the bulk composition in the investigated samples ranges from 3.18 to 10.5% with an average of 5.45%. The most important of them are magnetite, ilmenite, rutile, leucoxene, garnet, zircon and monazite. The existence of some radioactive-bearing accessory mineral deposits like zircon and monazite led to measuring the naturally occurring radionuclides 226Ra, 232Th and 40K to evaluate the excess lifetime cancer risk (ELCR). The results showed that these concentrations are 19.1 ± 9.73, 14.7 ± 9.53 and 211 ± 71.34 Bq kg-1 were lower than the corresponding reported worldwide average of 35, 45, and 412 Bq kg-1 for each radionuclide (226Ra, 232Th, and 40 K). The gamma hazard indices such as absorbed dose rate (Dair), the annual effective dose (AED), and excess lifetime cancer risk (ELCR) factor were computed in the investigated sediments and all the results were found (Dair = 26.4 nGy h-1, AED = 0.03 mSv year-1, ELCR = 0.0001) to be lower than the values suggested by the United Nations Scientific Committee on the effect of Atomic Research (59 nGy h-1, 0.07 mSv year-1 and 0.0029 for Dair, AED and ELCR, respectively). The study suggests that the black sand is safe to use in various infrastructure applications at Baltim-El Burullus coastal plain. The levels of radioactivity are not high enough to pose a risk to human health.

Anticardiolipin antibodies in rheumatoid arthritis.

The presence of anticardiolipin antibodies (aCL IgM & IgG), rheumatoid factor (RF) C-reactive protein (CRP) and antinuclear antibodies (ANA) were evaluated in 26 patients with rheumatoid arthritis (RA) disease [12 patients with acute disease (gr 1), 14 patients with chronic disease (gr 2) and 10 normal subjects as control (gr 3)]. aCL IgM was significantly increased in gr 1 & gr 2 when compared with gr 3 (P < 0.001 & P < 0.010 respectively). aCL IgG was non significantly increased in gr 1 & gr 2 when compared with gr 3 (P < 0.076 & P < 0.022 respectively). In group 1 75% of the patients were positive for a CLIgM, 25% positive for a CLIgG, 75% for RF, 58.3% for CRP, 25% positive for ANA Shaggy pattern and 33.3% positive for ANA speckled pattern. In group 2, the percent of positive cases were 42.85% for a CLIgM, 14.28% for a CLIgG, 42.8% for RF, 57.14% for CRP, 14.25% for ANA shaggy pattern and 28.57% for ANA speckled pattern. In the control group, all antibodies proved to be negative in every case. There was positive correlation between a CL IgM & aCLIgG and duration of disease in gr 1 & gr 2. There was positive correlation between a CLIgM and ESR in gr 1. There was negative correlation between a CLIgG and ESR in gr 1. There was negative correlation between a CLILgM & ESR in gr 2. There was positive correlation between a CLIgG & ESR in gr 2. We conclude that the presence of a CL antibodies (IgM & IgG) correlate well with the activity of disease, so this draw our attention to the importance of a CL antibodies as a parameter for prognosis of the disease.

Human red blood cell hemolysis in a turbulent shear flow: contribution of Reynolds shear stresses.

Various previous models used in studying red blood cell (RBC) hemolysis in turbulent shear flows are reviewed from a fluid dynamic point of view. The effect of turbulent shear stress (Reynolds shear stress, tau R) on RBC hemolysis is investigated utilizing a submerged axisymmetric jet flow field. A detailed survey of the flow field is made with a laser Doppler anemometer system to obtain contour maps of the mean velocity distributions, relative turbulence intensities, and tau R distributions in the field prior to conducting the experiment of sampling and analyzing the cells free-hemoglobin in the field. A new two-point sampling technique, developed in this laboratory, allows collections of RBC samples from selected locations in the flow field so that a relationship between the local shear stress level and the cell damage may be established. The threshold level of tau R responsible for incipient hemolysis is found to be approximately 400 Newtons per square meter (N/m2), below which a sublethal region of zero hemolysis is observed.

Influence of red blood cell concentrations on the measurement of turbulence using hot-film anemometer.

Measurement of local velocity fluctuations was made with an L-shaped conical hot-film probe in a submerged circular jet. The experiment was carried out in solutions of washed human red blood cells (RBC) in a phosphate buffer solution (PBS), at hematocrit concentrations (Ht percent) of 10, 19, 29, and 38 percent. The viscosity of the testing solutions was kept at 3.2 c.p. by adding proper amount of dextran. The experiment was conducted at Reynolds numbers (NR) 674, 963, 1255 and 1410, based on the jet exit velocity and exit diameter. Statistical analyses were performed on the recorded instantaneous velocity signals to obtain the root-mean-square (rms) values, the probability density functions (PDF) and the power spectral density functions (PSDF) of the signals. Within the range tested, we noticed an incidental rise in rms values at 19 to 29 Ht percent for NR = 963 similar to those reported earlier in the literature. Further analyses using PDF and PSDF, however, showed neither a trend nor any physical significance of this rise. Based on the analyses of both the PDF and the PSDF, we believe that the incidental rise in rms value can be partially attributed to the high spikes registered by the probe in a high RBC concentrations fluid flow. The bombardment of RBC on the probe thermal boundary layer may cause a characteristic change in the probe response to certain flow phenomenon, at least within the Reynolds number range used in this study.(ABSTRACT TRUNCATED AT 250 WORDS)