Non-Newtonian Rheology in Blood Circulation

Blood is a complex suspension that demonstrates several non-Newtonian rheological characteristics such as deformation-rate dependency, viscoelasticity and yield stress. In this paper we outline some issues related to the non-Newtonian effects in blood circulation system and present modeling approaches based mostly on the past work in this field.Comment: 26 pages, 5 figures, 2 table

Edmodo Learning Media and Meeting Room Help Grasp Simple and Significant Ones: Circulatory System

Biology is complex for students because of a lack of interest, uncertainty regarding healthy blood circulation, small and large blood circulation systems, remembering the order of blood circulation, and fast-paced education. Students need microcirculation groups. Significant and minor blood circulation groups must be understood and circulated by students. Old biology teaching methods failed students despite adopting technology. Teachers must master and use learning technology in our globalized environment. Online learning is current education technology. This research can help educators choose instructional resources, especially the exciting part of practitioners contributing to academic biology research. This study evaluates student motivation and circulation system learning with Edmodo and meeting room media. Classroom Action Research met twice. Research rigour evaluation needs learning and assessment criteria alignment. Planning, Action, Observation/Evaluation, and Reflection comprise each learning cycle. This study includes 20 grade 11 controls. Teachers and practitioners utilize Edmodo and Zoom for online learning. In the lesson plan, a 40-question two-level multiple-choice exam and a motivation survey assess student learning. The study is quantitative. From inception to finish, data analysis grades data quality 1–4. Researchers use observation, interviews, and questionnaires. Microsoft Excel averaged descriptive analysis data. It measures efficacy by the percentage increase in learning outcomes during learning. This essay analyzes how Edmodo impacts classroom learning, outcomes, and motivation

The Analysis of Indices of Cerebral Blood Circulation in Women-smokers

The results of rheoencephalography of female smokers 17–21 years old and control group were studied and analyzed. The aim of this work was to explain and analyze physiological features of smoking effect on functional changes of regional hemodynamics in smoking women.The study of cerebral hemodynamics was carried out by the method of rheoencephalography (REG) – automated system of complex examination “Askold”, intended for automation of medical tasks processing with input of information in “online” regime (insertion of data directly from examined person). The recording of rheogram was carried out in front-mastoid branches that allowed register REG separately in both hemispheres of brain and determine the main amplitude-temporal characteristics of cerebral blood circulation and changes of vascular tone.Analyzing the main indices of regional hemodynamics in female smokers, the statistically lower values of time of rheowave delay (Ra) were noted. There was also revealed a decrease of volumetric cerebral blood circulation and increase of resistant arteries tone. There were fixed the moderate asymmetry (from 15 to 25 %) of blood filling in vertebral-basilar vascular basin (basin of spinal and internal carotid arteries) and the signs of complicated venous outflow in both hemispheres.Such changes of indices indicate the decrease of volumetric blood circulation of cerebral hemodynamics, striking volume of blood and increase of tone of distribution arteries that testify to the decrease of blood circulation in main vessels, and also smoking is a cause of hypoxia (oxygen deprivation) of cerebral cells as a result of decrease of blood inflow. In the women of control group all indices are within norm that testifies to the normal course of physiological processes in organism

Evaluation of a pig femoral head osteonecrosis model

Background A major cause of osteonecrosis of the femoral head is interruption of a blood supply to the proximal femur. In order to evaluate blood circulation and pathogenetic alterations, a pig femoral head osteonecrosis model was examined to address whether ligature of the femoral neck (vasculature deprivation) induces a reduction of blood circulation in the femoral head, and whether transphyseal vessels exist for communications between the epiphysis and the metaphysis. We also tested the hypothesis that the vessels surrounding the femoral neck and the ligamentum teres represent the primary source of blood flow to the femoral head. Methods Avascular osteonecrosis of the femoral head was induced in Yorkshire pigs by transecting the ligamentum teres and placing two ligatures around the femoral neck. After heparinized saline infusion and microfil perfusion via the abdominal aorta, blood circulation in the femoral head was evaluated by optical and CT imaging. Results An angiogram of the microfil casted sample allowed identification of the major blood vessels to the proximal femur including the iliac, common femoral, superficial femoral, deep femoral and circumflex arteries. Optical imaging in the femoral neck showed that a microfil stained vessel network was visible in control sections but less noticeable in necrotic sections. CT images showed a lack of microfil staining in the epiphysis. Furthermore, no transphyseal vessels were observed to link the epiphysis to the metaphysis. Conclusion Optical and CT imaging analyses revealed that in this present pig model the ligatures around the femoral neck were the primary cause of induction of avascular osteonecrosis. Since the vessels surrounding the femoral neck are comprised of the branches of the medial and the lateral femoral circumflex vessels, together with the extracapsular arterial ring and the lateral epiphyseal arteries, augmentation of blood circulation in those arteries will improve pathogenetic alterations in the necrotic femoral head. Our pig model can be used for further femoral head osteonecrosis studies

Blood clearance and tissue distribution of PEGylated and non-PEGylated gold nanorods after intravenous administration in rats\ud

Aims: To develop and determine the safety of gold nanorods, whose aspect ratios can be tuned to obtain plasmon peaks between 650 and 850 nm, as contrast enhancing agents for diagnostic and therapeutic applications. Materials & methods: In this study we compared the blood clearance and tissue distribution of cetyl trimethyl ammonium bromide (CTAB)-capped and polyethylene glycol (PEG)-coated gold nanorods after intravenous injection in the tail vein of rats. The gold content in blood and various organs was measured quantitatively with inductively coupled plasma mass spectrometry. Results & discussion: The CTAB-capped gold nanorods were almost immediately (<15 min) cleared from the blood circulation whereas the PEGylation of gold nanorods resulted in a prolonged blood circulation with a half-life time of 19 h and more wide spread tissue distribution. While for the CTAB-capped gold nanorods the tissue distribution was limited to liver, spleen and lung, the PEGylated gold nanorods also distributed to kidney, heart, thymus, brain and testes. PEGylation of the gold nanorods resulted in the spleen being the organ with the highest exposure, whereas for the non-PEGylated CTAB-capped gold nanorods the liver was the organ with the highest exposure, per gram of organ. Conclusion: The PEGylation of gold nanorods resulted in a prolongation of the blood clearance and the highest organ exposure in the spleen. In view of the time frame (up to 48 h) of the observed presence in blood circulation, PEGylated gold nanorods can be considered to be promising candidates for therapeutic and diagnostic imaging purpose

Bronchial Circulation Angiogenesis in the Rat Quantified with SPECT and Micro-CT

Introduction As pulmonary artery obstruction results in proliferation of the bronchial circulation in a variety of species, we investigated this angiogenic response using single photon emission computed tomography (SPECT) and micro-CT. Materials and methods After surgical ligation of the left pulmonary artery of rats, they were imaged at 10, 20, or 40 days post-ligation. Before imaging, technetium-labeled macroaggregated albumin (99mTc MAA) was injected into the aortic arch (IA) labeling the systemic circulation. SPECT/micro-CT imaging was performed, the image volumes were registered, and activity in the left lung via the bronchial circulation was used as a marker of bronchial blood flow. To calibrate and to verify successful ligation, 99mTc MAA was subsequently injected into the left femoral vein (IV), resulting in accumulation within the pulmonary circulation. The rats were reimaged, and the ratio of the IA to the IV measurements reflected the fraction of cardiac output (CO) to the left lung via the bronchial circulation. Control and sham-operated rats were studied similarly. Results The left lung bronchial circulation of the control group was 2.5% of CO. The sham-operated rats showed no significant difference from the control. However, 20 and 40 days post-ligation, the bronchial circulation blood flow had increased to 7.9 and 13.9%, respectively, of CO. Excised lungs examined after barium filling of the systemic vasculature confirmed neovascularization as evidenced by tortuous vessels arising from the mediastinum and bronchial circulation. Conclusion Thus, we conclude that SPECT/micro-CT imaging is a valuable methodology for monitoring angiogenesis in the lung and, potentially, for evaluating the effects of pro- or anti-angiogenic treatments using a similar approach

Effect of blood's velocity on blood resistivity

Blood resistivity is an important quantity whose value influences the results of various methods used in the study of heart and circulation. In this paper, the relationship between blood resistivity and velocity of blood flow was evaluated and analyzed based upon a probe using six-ring electrodes and a circulatory model. The experimental results indicated that the change in blood resistivity was only ±1.1% when the velocity of blood flow changed from 2.83 to 40 cm/s and it rose to 23% when the velocity was lower than 2.83 cm/s

Hypothalamically-Induced Insulin Release and its Potentiation During Oral and Intravenous Glucose Loads

Male Wistar rats were provided with bilateral cannulas in the lateral hypothalamic area (LHA) and cannulas in the left and right jugular vein. Freely moving rats provided in this way with cannulas were infused with transmitters in the LHA and with various substances in the blood circulation during simultaneous sampling of blood without disturbing the animals. Infusion of norepinephrine (NE) in the LHA resulted in increased insulin levels while plasma glucagon and blood glucose were nearly not affected. This LHA mediated insulin release was suppressed by atropine injection in the blood circulation suggesting a vagal contribution to the observed phenomenon. Administration of either an oral or i.v. glucose load during noradrenergic stimulation of the LHA elicited an exaggerated insulin response when compared to their controls. This LHA potentiated insulin response during an oral and i.v. glucose load could be suppressed by atropinization of the rats. It is concluded that meal-related stimuli are relayed to the NE-stimulated area of the LHA and that these stimuli modulate the output from this area of the LHA that is concerned with the release of insulin.