The venous system of the human foetal spinal cord. Scanning electron microscope of vascular corrosion casts

The investigation was carried out on 16 human foetal cadavers at the age of 17–23 weeks from the time of conception. The foetal vascular system was injected with the synthetic resin MERCOX CL-2R and analysed in scanning electron microscope.The vascular system of the foetal spinal cord was studied. The foetal vascular system was characterised by high variability concerning the number, course and localisation of blood vessels. It contained numerous anastomoses with the internal spinal venous plexuses, which included anterior and posterior radicular veins. Large arteries running on the surface of the spinal cord are accompanied by the homoname veins. The venous system of the investigated foetuses was divided into 2 categories of veins: internal veins responsible for the drainage of blood from the central area, that is central and peripheral veins coming radially to the surface of the spinal cord and external veins, which form the venous system of the surface of the spinal cord. The venous system of the foetal spinal cord was also examined as to the presence of the valves

Application of a lumped parameter code for prediction of hydrogen distribution within containments of water reactors

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.The lumped parameter code HEPCAL has been worked out in the Institute of Thermal Technology of the Silesian University of Technology for simulations of pressurized water reactor containments response to accidental conditions, especially during loss-of-coolant accidents (LOCA). Within the framework of this work the HEPCAL code has been applied for simulations of hydrogen behavior within containments of Advanced Boiling Water Reactor (ABWR) and European Pressurized Reactor (EPR). The focus has been put on hydrogen distribution thorough subcompartments of the containment building. A dynamics of creating flammable mixtures and operation of hydrogen removal systems were also the subjects of analysis.cf201

The structure of acquired aural cholesteatoma as revealed by scanning electron microscopy

The structural features of cells, their surfaces and the extracellular matrix were investigated in acquired aural cholesteatoma. Cholesteatomas surgically removed from 30 patients were examined by a scanning electron microscope (SEM). The predominant part of a cholesteatoma was composed of stratified squamous epithelium, showing extensive chaotic desquamation. The surface sculpture of the keratinocytes and corneocytes varied from parallel ridges, irregular microplicae and mirovilli, to flat grooves and pits and a completely smooth surface. Sheetlike lamellar structures, probably representing an intercellular lipid-forming permeability barrier, were also observed. Small crystals located in the perimatrix were observed in one case. According to the SEM observations, cholesteatoma epithelium is characterised by abnormal and uncoordinated keratinisation, with a predominance of the advanced stages of the process. Folia Morphol 2008; 67: 8–12

Microvascular System of the Human Fetal Inner Ear: A Scanning Electron Microscopic Study of Corrosion Casts

The vascular system of the inner ear was investigated in 18-21 weeks old human fetuses, using the corrosion cast technique in scanning electron microscopy. At that developmental stage, vascularization of the cochlea and semicircular canals shows a pattern very similar to that described for adults. The most important differences which can be regarded as fetal features include: (1) denser limbus vessels, (2) the marginal vessels of the spiral lamina appearing as irregular network which shows a less clear arcade-like arrangement, (3) some radiating arterioles of the spiral lamina and marginal vessels possessing connections with the vascular system of the external wall, and (4) a dense, sinusoidal network of draining venules at scala tympani. These features apparently disappear during the final remodelling of the inner ear microvasculature in the last trimester

Fatty tissue within the maxillary sinus: a rare finding.

BACKGROUND: We report a rare case of fatty tissue within the maxillary sinus in a 21-years-old woman, with a history of several previous punctures of the maxillary sinus. CASE PRESENTATION: Clinical data of the patient was analysed retrospectively. The patient presented with symptoms of left-sided chronic maxillary sinusitis and had undergone several punctures of the left maxillary sinus 18 months earlier. Subsequent to one of the procedures an acute pain in the left orbit lasting a couple of days was noted. Left endoscopic transnasal antrotomy was performed. The maxillary sinus was filled with polypous, chronically inflamed mucous membrane. Upon its removal, the maxillary roof was identified as drawn downwards and covered with normal mucous membrane. Upon dissection of the membrane, adipose tissue filling the zygomatic recess of the sinus was identified and subsequently removed. The maxillary roof was unchanged. Histopatologic examination confirmed the material to be adipose tissue. No short or long term sequelae occurred. CONCLUSION: Adipose tissue can be found in the maxillary sinus most commonly when penetrating from surrounding locations. It is our hypothesis that in the reported patient it penetrated from the orbit to the maxillary sinus following puncture. It seems that a hole in the maxillary sinus roof, about 1 mm in diameter, caused by the needle, may have been a portal of entry for the adipose tissue into the maxillary sinus. The discussed case suggests particular care be taken in performing puncture of the maxillary sinus

Stress distribution in dewatered filter cakes

W pracy przedstawiono analizę procesu powstawania naprężeń w osadach filtracyjnych odwadnianych przez przedmuchiwanie powietrzem. Wewnątrz osadu powstaje nierównomierny rozkład nasycenia filtratem. W pracy przedstawiono mechanizm i model operacji odwadniania oraz wyjaśniono zjawisko powstawania nierównomiernego rozkładu naprężeń wewnątrz osadu. Model pozwala na wyznaczenie rozkładów odkształceń i naprężeń powstających wewnątrz osadu.Study of stress formation in cakes dewatered by air blowing is presented in the paper. Inside a cake irregular saturation distribution is created during de-watering. The mechanism and model of dewatering process were described and phenomenon of irregular stress distribution was explained. The model enables the estimation of strain and stress distribution created inside a filter cake

Identification of pore size distribution in a filter cake

W pracy zaproponowano procedurę identyfikacji rozkładu wielkości porów na podstawie krzywej ciśnienia kapilarnego oraz rozkładu granutometrycznego materiału ziarnistego. Model osadu filtracyjnego zakłada, że każdej cząstce ciała ziarnistego przyporządkowana jest przestrzeń międzyziarnowa oraz strefa martwa. Model zweryfikowano eksperymentalnie. Wyznaczono przeciętną wielkość porów osadu filtracyjnego oraz odchylenie standardowe.The identification procedurę dealing with porę size distribution on basis of capillary pressure curve and particle size distribution of granular materiał is proposed in the paper. The fitter cake model assumes that a sphericai pore and dead żone are assigned to each particle. The model was experimenta Hyve rified and porę size distribution parameters such as the mean pore size and standard deviation were estimated

Prognozowanie efektywności pracy krzyżowoprądowego wymiennika ciepła w warunkach niejednorodnego przepływu czynników

The paper deals with numerical thermodynamic analyses of cross-flow finned tube heat exchangers of the gas-liquid type. The authors postulate that some improvement of the heat exchanger performance may be achieved by applying a special ribbing structure - fitted to certain media flow conditions. First, the measurements have been carried out in order to determine the air inflow non-uniformity and next an own computer code HEWES has been used for numerical simulations in order to evaluate the impact of the measured non-uniformity on the exchangers' efficiency for the heat exchangers with unified ribbing structure. The numerical simulations have been repeated for heat exchangers with special ribbing structures - determined on the basis of experimental results. Results confirm the hypothesis - some increase in the total heat flow rate may be observed for the considered heat exchanger.Praca dotyczy termodynamicznej analizy krzyżowoprądowego, ożebrowanego wymiennika ciepła typu gaz-ciecz. Autorzy weryfikowali hipotezę zakładającą możliwość uzyskania poprawy efektywności działania urządzenia w wyniku zastosowania specjalnej, dostosowanej do warunków przepływu czynników, struktury ożebrowania. W pierwszej kolejności wykonane zostały pomiary określające zakres i postać niejednorodnego dopływu powietrza do analizowanego wymiennika ciepła, a następnie wykorzystano własny kod komputerowy HEWES do oceny wpływu tej niejednorodności na wydajność cieplną wymiennika. Obliczenia te dotyczyły wymiennika ciepła z jednorodnym ożebrowaniem. Symulacje numeryczne zostały następnie powtórzone dla przypadku wymiennika ze specjalną strukturą ożebrowania, która została dobrana dla wyznaczonych eksperymentalnie warunków dopływu powietrza. Uzyskane rezultaty potwierdzają postawioną na wstępie hipotezę - widoczny jest pewien wzrost wartości strumienia ciepła przekazywanego w wymienniku

Efficiency of gravity dewatering of municipal sewage on belt thickeners

Zaprezentowano wyniki eksperymentów, przeprowadzonych na urządzeniu testowym w skałi laboratoryjnej, polegających na grawitacyjnym zagęszczaniu komunalnych ścieków pofermentacyjnych zmieszanych z różnymi dawkami flokulanta syntetycznego w postaci polielek-trolitu kationowego. Wyznaczono krzywe odwadniania dła każdej dawki dozowanego polimeru. Wykazano, że na podstawie analizy otrzymanych krzywych można dokonać wyboru optymałnej ilości dozowanego polielektrolitu.Results of experimental tests on gravity dewatering of municipal sewage sludges were presented in the paper. Experiments on gravity dewatering of sewage studges conditioned with different quantity of fiocculation agent, i.e. cationic polyelectrolyte, were carried out in a laboratory stand. As a result of these investigations a series of dewatering curves were obtained. It was confirmed that on the basis of dewatering curves the optimum dosage of polyelectrolyte could be suggested