Zeitschrift für Bioingenieurwesen und biomedizinische Wissenschaft

Background: A method for generating bronchial tree would be helpful when constructing models of the tree for benchtop experiments as well as for numerical modeling of flow or sound propagation in the airways. Early studies documented the geometric details of the human airways that were used to develop methods for generating human airway tree. However, methods for generating animal airway tree are scarcer. Earlier studies suggested that the morphology of animal airways can be significantly different from that of humans. Hence, using algorithms for the human airways may not be accurate in generating models of animal airway geometry.

Objective: The objective of this study is to develop an algorithm for generating pig airway tree based on the geometric details extracted from the physical measurements. Methods: In the current study, measured values of branch diameters, lengths and bifurcation angles and rotation of bifurcating planes were used to develop an algorithm that is capable of generating a realistic pig airway tree.

Results: The generation relations between parent and daughter branches were found to follow certain trends. The diameters and the length of different branches were dependent on airway generations while the bifurcation angles were primarily dependent on bifurcation plane rotations. These relations were sufficient to develop rules for generating a model of the pig large airways.

Conclusion: The results suggested that the airway tree generated from the algorithm can provide an approximate geometric model of pig airways for computational and benchtop studies.

Recordings of biological signals such as vibrocardiography often contain contaminating noise. Noise sources may include respiratory, gastrointestinal, and muscles movement, or environmental noise. Depending on individual physiology and sensor location, the vibrocardiographic (VCG) signals may be obscured by these noises in the time-frequency plane, which may interfere with automated characterization of VCG. In this study, polynomial chirplet transform (PCT) and smoothed pseudo Wigner-Ville distribution (SPWVD) were used to estimate the instantaneous frequency (IF) of two simulated VCG signals. One simulated signal contained a time-varying IF while the other had a fixed IF. The error in estimating IF was then calculated for signal-to-noise ratios (SNR) from -10 to 10 dB. Analysis was repeated 100 times at each level of noise using randomized sets of white noise. Error analysis showed that the range of errors in estimating IF was wider when SNR decreased. Results also showed that PCT tended to outperform SPWVD at high SNR. For example, PCT was more accurate at SNR > 3 dB for a simulated VCG signal with constant frequency components, at SNR>-10 dB for a simulated VCG signal with time-varying frequency, and at SNR > 0 for an actual VCG.

A high potential iron-Sulphur protein (HiPIP) Iron Oxidase (E.C 1.9.3.1) was isolated from Acidithiobacillus species obtained from Ironstones of Agbaja Mines of Kogi State, Nigeria. The aim was to study the biochemical characteristics of the enzyme so as to find out its catalytic contribution to the rate of bioleaching of the studied organism. A simple partial purification profile consisting of cell homogenization, ammonium sulphate precipitation, Ion-exchange using Carboxyl methyl cellulose, and sephadex G-200 chromatography were used. The biochemical and kinetic properties of the enzyme were thereafter studied. The Iron oxidase had its highest specific activity of 14.70 μmole/ml/mg of protein and yield of 89% with a purification fold of 1.43 after size exclusion chromatography. Optimum temperature and pH were found to be 50°C and 6.0 with Km and Vmax of 0.03mM and 12 mMole/min respectively. Inhibition studies conducted shows that tween 20 and SDS had the maximum rates. Other characteristics of the enzyme show that it might be a novel member of HiPIP coming from the isolated Acidithiobacillus of Agbaja Iron ore Mines.

The aim of the European project Nephron+ is the design of a wearable artificial kidney device. This paper is focused on the design of the corresponding ultralow-hemolysis continuous- operation blood pump. Accurate specifications and operating principle of the pump are determined. A first nonoptimal configuration of a linear electromechanical actuator which will be used to pump the blood is designed. Its prototype is presented along with the corresponding driving electronic circuit. Finally, based on the measurements, the actuator is optimized, and the final design and first experimental results are presented.

In order to reduce dependency on petroleum fuels, Turkey, a country located in Southeastern Europe and Southwestern Asia, in search of new energy sources like the other countries. Modern energy services can be considered as renewable energy technologies (RETs) which are sustainable and abundant in the country. However considering the total cost of RET production, renewable energy sources can be used not to replace the fossil fuels, but to supply energy requirement in rural areas, in order to decrease the imported energy resources that place a big burden on the economy. In this study, the renewable energy resources in Turkey were comparatively expressed, regards to the potential and current use. This paper was aimed to provide an overview of worldwide examples and projects for the use of renewable energy technologies that can also be applied in Turkey, which has a proportion of rural population, to increase the access to modern energy services in rural areas in the country. For these purposes, the rural and nationwide renewable energy productions were compared and the limitations and prospects were also discussed.

An effort has been made to prepare gel matrices using different concentrations of Carrageenan whose particle sizes could be exploited in the nanoscale. The Single emulsion technique has been employed for gel formulation. After formulation, gels were characterized for their particle size and zeta potential. Fourier Transform Infrared Spectroscopy (FTIR) was used in the analysis of nanogels, scanning electron microscopy (SEM) to envision the surface microstructures was also performed. It was found that average particle size was in the range of 2000- 4000 nm after drug entrapment and the particles were found to be spherical in shape. The entrapment efficiency of the model drug (Indomethacin) in gel matrix was found to be nearly 40%. Finally, the in vitro release profiles of indomethacin from the nanogel matrices were evaluated spectrophotometrically at 266 nm. Drug release from nanogel consisting of 4% carrageenan was found to be 68% for up to 24 h. Finally, the results have indicated that the Carrageenan nanogel carriers could be used for drug delivery applications.