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Biomedical subjects

H Chmiel

Publications and source records attributed to H Chmiel.

At least 19 recordsLinked to original sources
PubMed2003

Hybrid flotation--membrane filtration process for the removal of heavy metal ions from wastewater.

A promising process for the removal of heavy metal ions from aqueous solutions involves bonding the metals firstly to a special bonding agent and then separating the loaded bonding agents from the wastewater stream by separation processes. For the separation stage, a new hybrid process of flotation and membrane separation has been developed in this work by integrating specially designed submerged microfiltration modules directly into a flotation reactor. This made it possible to combine the advantages of both flotation and membrane separation while overcoming the limitations. The feasibility of this hybrid process was proven using powdered synthetic zeolites as bonding agents. Stable fluxes of up to 80l m(-2)h(-1) were achieved with the ceramic flat-sheet multi-channel membranes applied at low transmembrane pressure (<100 mbar). The process was applied in lab-scale to treat wastewater from the electronics industry. All toxic metals in question, namely copper, nickel and zinc, were reduced from initial concentrations of 474, 3.3 and 167mg x l(-1), respectively, to below 0.05 mg x l(-1), consistently meeting the discharge limits.

Conservation of Natural Resources↗
PubMed1990

Effects of oxygen supply on the production of nikkomycin with immobilized cells of Streptomyces tendae.

For continuous production of the antibiotic nikkomycin immobilized cells have been used in a fluidized bed bioreactor. Cells of Streptomyces tendae were immobilized on sintered glass particles. Different biomass concentrations on the particles correspond to different thicknesses of mycelial layers because growth occurs only on the outer surface of the particles. The antibiotic productivity decreased with increasing layer thickness. In fermentations with higher concentrations of both biomass on the particles and dissolved oxygen levels of about 70% the productivity was also limited because of limited oxygen diffusion in the layers.

Aminoglycosides↗
PubMed1990

A study of N- and P-dependence of nikkomycin production in continuous culture with immobilized cells.

The influence of nitrogen and phosphate on the biosynthesis of nikkomycin was studied in chemically defined medium. Cells of Streptomyces tendae were immobilized on porous glass particles in a fluidized-bed reactor for continuous production of nikkomycin. Phosphate had no significant influence on the biosynthesis of nikkomycin. However, even a very low concentration of phosphate in the production medium (0.0125 mmol/l) resulted in microbial growth on the particles. The concentration of nitrogen was highly effective in the regulation of the biosynthesis of nikkomycin. A high level of antibiotic production (maximum 3.05 mg/g dry cell weight per hour) was maintained for a period of about 200 h in a medium that contained nitrogen at a concentration of 0.2 g NH4NO3/l.

Aminoglycosides↗
PubMed1990

The determination of blood viscoelasticity in clinical hemorheology.

A brief outline of the background of viscoelasticity of blood is given in order to derive for blood relevant parameters. In this context, especially one method, the sinusoidal oscillating capillary rheometry, is discussed. The determination of different parameters to characterize blood samples, e.g. the viscoelastic phase angle, an aggregation index, a flexibility index, hematocrit and plasma viscosity is described. Most of these parameters show increased values in disease; however they can be influenced by drug treatment.

Blood Viscosity↗
PubMed1988

Evaluation of viscoelasticity measurements of human blood.

The dependence on hematocrit of whole blood viscoelasticity must be considered in order to compare pathological blood samples to normal ones. If one wants to calculate the measured values to a standard hematocrit value, the hematocrit dependence for the pathological sample must be available. As the latter however is unknown, the same dependence is assumed for both normal and pathological blood samples. To prove the validity of this assumption, hematocrit dependence of random blood samples from different diseases (cerebral and coronary vascular and myocardial disorders) were investigated. A statistical analysis showed the assumption as invalid. Therefore, it will be recommended to evaluate pathological blood samples at the measured hematocrit.

Blood Viscosity↗
PubMed1983

The measurement of density and its significance in blood rheology.

When viscoelasticity is measured with an oscillating capillary rheometer, the density of the fluid under study is an influencing factor (inertia). In the particular case of blood rheology hematocrit is also of interest. It can be measured more exactly on the basis of the density of blood and blood plasma than by conventional methods using a hematocrit centrifuge or Coulter counter, as these give too high readings when there is an increased tendency towards erythrocyte aggregation and reduced erythrocyte flexibility. Due to the double significance of blood density for blood viscoelasticity, an oscillating capillary rheometer and a new type of density-measuring device were attached to a computer in such a way that simultaneous evaluation is possible. The density-measuring device is a U-tube that is set into oscillation electronically. The duration of the oscillation is an indication of the density of the fluid in the U-tube.

Blood Physiological Phenomena↗
PubMed1981

The influence of I.V. application of pentoxifylline on the viscoelasticity of blood in patients with peripheral vascular disorders.

Viscoelastic parameters of blood from 9 patients with vascular disorders before and at different time intervals after POF infusion were investigated. There was a significant decrease in both parameters up to 1h after the end of POF application. Parallel measurements of hematocrit, density of whole blood and plasma, and particle volume distribution of RBC's would suggest that this drug reduces the enhanced aggregation tendency of RBC present in most pathological conditions.

Aged↗
PubMed1979

Theoretical aspects of adsorption of polar substances from polar solvents.

The efficiency of adsorbents for hemoperfusion and dialysate regeneration can be increased if suitable catalysts are fixed on their surface in an appropriate density. Suitable catalysts are oxides and salts of the transition metals. The appropriate surface density of the catalysts depends on the molecular data of both catalyst and toxin to be removed, as well as on the distribution of the adsorption sites on the adsorbent surface area. The distribution of the adsorption sites is determined by means of photoelectron spectroscopy and adsorption and desorption measurements.

Adsorption↗