53 research outputs found
Fluid and particle retention in the greater kudu (Tragelaphus strepsiceros)
On the one hand, the greater kudu (Tragelaphus strepsiceros) is a strict browser and would therefore be expected to display a ‘moose-type’ digestive physiology with a comparatively low rumen fluid throughput, a low ratio of small particle to fluid mean retention time (MRT) in the reticulorumen (RR), and relatively unstratified RR contents. On the other hand, reports on relatively small salivary glands, susceptibility to negative effects of tannins, and a putative absence of tannin-binding salivary proteins would suggest the greater kudu to be an exceptional browser with a ‘cattle-type’ digestive physiology. We measured MRT in four zoo-kept greater kudu females, which resulted in a MRTparticleRR/MRTfluidRR ratio between 1.07–1.43, well within the range of ‘moose-type’ ruminants and similar to eland (Taurotragus oryx). In this regard, consistent morphophysiological studies on greater kudu are required to resolve the seemingly contradictory findings in this species
The influence of plasma nitriding on the microstructure of X153CrMoV12 and X165CrV12 steels
This study presents the results of research into the influence of the time of the plasma nitriding process on the microstructure of the coatings obtained on cold-work tool steels X153CrMoV12 and X165CrV12. The processes were carried out under industrial conditions using an Ionit system (Oerlikon Metaplas) with variable process times of 2, 4 and 6 hours. Nitriding mixture consisting of 5 % nitrogen and 95 % hydrogen was chosen, which allowed the expected diffusion layer to be obtained without a white layer (composed of iron nitrides). Analysis of relative elemental concentrations indicates that the presence and content of nitride-forming elements influences the formation of alloy additive nitrides in the microstructure of the diffusion layer. Nitrides of alloying additives, present in the diffusion layer, indicating that investigated steels are the most suitable for plasma nitriding
Deciphering the role of ectosomes in cancer development and progression : focus on the proteome
L1CAM from human melanoma carries a novel type of N-glycan with Galβ1-4Galβ1- motif. Involvement of N-linked glycans in migratory and invasive behaviour of melanoma cells
A spline model of the dynamic properties of an electrochemical oxygen sensor
Artykuł przedstawia nową koncepcję budowania modeli właściwości dynamicznych elektrochemicznego czujnika tlenu. Koncepcja polega na wyznaczaniu sygnału wyjściowego czujnika jako funkcji sklejanej z obliczanych przediałami rozwiązań układu równań różniczkowych, o współczynnikach zależnych od kierunku zmian mierzonego stężenia tlenu. Przedstawiono model operacji sklejania oraz wyniki eksperymentalnej weryfikacji modelu sklejanego.The article presents a new concept of constructing models of electrochemical oxygen sensor dynamic properties. The concept consists in the evaluation of sensor output signal as a spline function from the calculated at intervals solutions of a system of differential equations with coefficients dependent on the direction of oxygen concentration changes. A model of the operation of splining as well as the results of the experimental model verification have been shown
DEMATEL-based multi-criteria evaluation of public transportation systems for Cracow
Praca poświęcona jest wieloatrybutowej ocenie perspektywicznych wariantów systemu transportowego dla miasta Krakowa i jego regionu. Rozpatrzono 4 warianty pozwalające na usprawnienie obecnie funkcjonującego, nieefektywnego systemu komunikacyjnego. Istotnym atutem pracy jest wykorzystanie w tym celu interesującej, lecz stosunkowo słabo znanej i wykorzystywanej na świecie metody DEMATEL (ang. DEcision MAking Trial and Evaluation Laboratory). Jej wykorzystanie pozwala pogłębić wyniki oryginalnej analizy, przeprowadzonej przy użyciu metody AHP/ANP.Multi-criteria evaluation of perspective public transportation systems for the city of Cracow and Cracow agglomeration is dealt with in the paper. Four distinct system alternatives are included. A little known multi-criteria decision analysis method, namely extended DEMATEL is applied with this regard. Its utilisation makes validation of outcomes of original AHP-based analysis of the same problem possible. It also extends analysis results providing decision maker with additional information with regard to relations between considered decision making alternatives
Nanostructural characteristics of genetic material for gene therapy application
Terapia genowa jest obecnie bardzo dynamicznie rozwijającą się techniką biomedyczną, która może znaleźć zastosowanie w medycynie w leczeniu chorób przewlekłych i dziedzicznych. Badania skupiają się na opracowywaniu nowych strategii dotyczących procesów kondensacji i ochrony materiału genetycznego (DNA) wprowadzanego do komórki docelowej. Struktura i stopień upakowania dostarczanego DNA wpływają na kluczowe właściwości fizykochemiczne, determinujące czy wprowadzony wektor rekombinowany ulegnie ekspresji, czy też degradacji. Związki chemiczne, zwane czynnikami kondensującymi, to substancje powodujące zwinięcie DNA, a stopień kondensacji materiału genetycznego zależy bezpośrednio od rodzaju i stężenia użytego czynnika kondensującego. Do cząsteczek wykazujących właściwości kondensujące należą poliaminy, w opisywanym eksperymencie zastosowano poliaminę – spermidynę. Przeprowadzone badania miały na celu charakterystykę nanostrukturalną materiału genetycznego pod wpływem działania czynnika kondensującego. W wyniku analizy wykonanej za pomocą mikroskopii sił atomowych (AFM) wykazano, że plazmid DNA ulega kondensacji pod wpływem spermidyny, formując struktury rozetowe.Gene therapy is a new promising method that may find many applications in modern biomedicine. Especially, it may be a powerful tool in chronic and hereditary diseases treatment. Current studies focus on development of novel strategies concerning genetic material (DNA) condensation and protection, whilst it is introduced into the cellular nucleus. Once the DNA enters the cell, it’s either passed on and expressed in the nucleus or degraded by intracellular nucleases. The structure and the degree of compaction influence physicochemical properties that determine what will happen to delivered genetic material. DNA coiling can be caused by chemical compounds called compaction agents, such as polyamines like spermidine used in this study. The aim of this research was to examine the nanostructural characteristics of genetic material exposed to compaction agent. The measurements and analysis performed by atomic force microscopy (AFM) indicate that DNA plasmid undergoes condensation and forms rosette-like structures once subjected to spermidine
Distant Measurement of Plethysmographic Signal in Various Lighting Conditions Using Configurable Frame-Rate Camera
Videoplethysmography is currently recognized as a promising noninvasive heart rate measurement method advantageous for ubiquitous monitoring of humans in natural living conditions. Although the method is considered for application in several areas including telemedicine, sports and assisted living, its dependence on lighting conditions and camera performance is still not investigated enough. In this paper we report on research of various image acquisition aspects including the lighting spectrum, frame rate and compression. In the experimental part, we recorded five video sequences in various lighting conditions (fluorescent artificial light, dim daylight, infrared light, incandescent light bulb) using a programmable frame rate camera and a pulse oximeter as the reference. For a video sequence-based heart rate measurement we implemented a pulse detection algorithm based on the power spectral density, estimated using Welch’s technique. The results showed that lighting conditions and selected video camera settings including compression and the sampling frequency influence the heart rate detection accuracy. The average heart rate error also varies from 0.35 beats per minute (bpm) for fluorescent light to 6.6 bpm for dim daylight
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