742 research outputs found

    Macroscopic structure and physiology of the normal and diseased heart

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    This paper outlines the macroscopic anatomy and physiology of the heart, linking the micro and macroscopic structure of cardiac muscle fibre to its function during contraction and dilatation. The properties of cardiac muscle cells and the process of contraction at a cellular level are described. The macroscopic structure of the myocardium is further explained as one muscle band wound into a double twist. This helps to elucidate the muscle architecture and structure of the ventricles. Ventricular dynamics are also described as the twisting and untwisting of this muscle band to produce shortening and lengthening. Myocardial perfusion and causes of disease are discussed. Coronary artery disease and its effect on contractility is then described and ways of measuring contractility are introduced

    Synthetic Fungal Strains for Solar System Exploration and Colonization

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    Solar system exploration and eventual colonization efforts are constrained by limits on the mass of material that can embark from Earth. Thus, creative use of the resources available in situ could reduce mission costs and extend the scope of such activities. To that end, we are developing synthetic fungal strains to produce specialized materials from the resources found throughout the solar system. A primary goal is to develop a suite of Saccharomyces cerevisiae strains to serve as generic production chassis for synthetic metabolic pathways. These strains must perform consistently upon challenge by unique conditions including exposure to microgravity, cosmic radiation, the rigors of launch and re-entry, and long-term stasis. Presently, we are establishing systematic datasets profiling epigenetic, transcriptional, translational and metabolic states of S. cerevisiae under relevant operating conditions. These will deepen our understanding of the physiological changes associated with space travel and enable rational engineering of optimal production strains

    Tool wear prediction on sheet metal forming die of automotive part based on numerical simulation method

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    Tool wear is a main concern in the sheet metal forming of automobile parts due to the development and application of new materials and the high requirement of parts quality in automobile production. However, it is difficult and time-consuming to predict tool wear using a traditional method. This paper provides a rapid numerical simulation approach for predicting the tool wear on sheet metal forming die. The simulation was carried out using the finite element software AutoForm™. A tool wear model was presented as a foundation of the simulation. The recommended protection method for the die surface and the prediction of tool worn areas was obtained from the simulation. The predicted results were in accordance with the results obtained from the on-site production. The influences of the contact pressure and drawing depth on the tool worn area distribution were also investigated based on the simulation outcome

    Effects of Polyhydroxybutyrate Production on Cell Division

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    Synthetic biological engineering can be utilized to aide the advancement of improved long-term space flight. The potential to use synthetic biology as a platform to biomanufacture desired equipment on demand using the three dimensional (3D) printer on the International Space Station (ISS) gives long-term NASA missions the flexibility to produce materials as needed on site. Polyhydroxybutyrates (PHBs) are biodegradable, have properties similar to plastics, and can be produced in Escherichia coli using genetic engineering. Using PHBs during space flight could assist mission success by providing a valuable source of biomaterials that can have many potential applications, particularly through 3D printing. It is well documented that during PHB production E. coli cells can become significantly elongated. The elongation of cells reduces the ability of the cells to divide and thus to produce PHB. I aim to better understand cell division during PHB production, through the design, building, and testing of synthetic biological circuits, and identify how to potentially increase yields of PHB with FtsZ overexpression, the gene responsible for cell division. Ultimately, an increase in the yield will allow more products to be created using the 3D printer on the ISS and beyond, thus aiding astronauts in their missions

    Appendicitis with appendicular atresia: A rare presentation

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    Acute appendicitis is the most common acute surgical condition; making appendectomy the most commonly performed emergency surgical procedure in the world. Anomalies of the appendix are relatively  uncommon. However, their presence may alter the course of pre-operativediagnosis and the surgical treatment provided, leading to medico-legal issues in certain cases as well. We hereby present the case of a 17  year-old female who had the suggestive signs, symptoms and  investigations of appendicular lump. She was managed according to the Ochsner-Sherren regimen and then underwent interval open appendectomy 6 weeks later. During the procedure, the findings of a 5 cm long appendix were noted. The base of the appendix was attached to the caecum, however there was complete mucosal discontinuity between the base and the remaining portion of the appendix. A fibrous strand connected the two blind ending parts together. After thorough literature search, the authors concluded that this is only the fourth reported case of appendicular atresia ever to have been reported. Considering the rarity of this finding we feel this could be of valuable interest to surgeons and readers alik

    Efecto de la hormona de crecimiento sobre los parámetros seminales, el hemograma parcial y el nivel de testosterona en búfalos Nili Ravi

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    The purpose of this trial was to examine the possible effects of exogenous growth hormone (GH) on semen quality, hematological variables and serum testosterone concentration in Nili Ravi buffalo. Bulls of the treatment group (n=3) were injected with recombinant GH 500 mg in a 15 day interval for 10 consecutive weeks, while bulls of control group (n=3) received equal volume of normal saline solution. Semen samples were collected twice per week and analyzed for physiological parameters. Blood samples collected fortnightly were analyzed for red blood cells count (RBC), hemoglobin concentration (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), white blood cell (WBC), neutrophils, lymphocytes, and serum testosterone levels. Data were analyzed statistically using t-test. Results indicated that GH treatment of Nili-Ravi buffaloes significantly (p<0.05) increased ejaculatory volume (8.8±0.2 vs 7.7±0.2 ml), sperm motility (72.6±0.4 vs 67.4±0.7%), mass activity (3.35±0.07 vs 2.52±0.08), sperm concentration (982.2±67.8 vs 731.9±50.5 million/ml), live sperm (80.1±0.3 vs 75.8±0.5%) and serum testosterone (4.02±0.21 vs 2.37±0.07 ng/ml) compared to control bulls. Among hematological variables, lymphocytes were increased (p<0.05), but MCV, WBC count, and neutrophils decreased (p<0.05). Hb, RBC and PCV remained unchanged. However, values of these variables were within normal ranges for buffalo bulls. In conclusion, treatment of Nili-Ravi bulls with GH improved semen quality and increased serum testosterone without ostensible adverse effects on the general state.El propósito de este ensayo fue examinar los posibles efectos de la hormona de crecimiento exógena (GH) sobre la calidad del semen, algunas variables del hemograma y la concentración de testosterona en suero de toros bubalinos Nili Ravi. Los búfalos del grupo tratado (n=3) fueron inyectados con 500 mg de somatotropina recombinante cada 15 días durante 10 semanas consecutivas, mientras que los del grupo control (n=3) recibieron igual volumen de solución fisiológica salina. Las muestras de semen fueron tomadas dos veces por semana y analizadas para evaluar los parámetros fisiológicos. Las muestras de sangre colectadas quincenalmente fueron analizadas para establecer el recuento de glóbulos rojos, la  concentración de hemoglobina, el hematocrito, el volumen corpuscular medio (MCV), recuento de glóbulos blancos (WBC), tasa de neutrófilos y linfocitos, así como los niveles séricos de testosterona. Los datos obtenidos fueron analizados estadísticamente por medio del test-t de Student. Los resultados indicaron que el tratamiento con somatotropina aumentó significativamente (p<0,05) el volumen eyaculado (8,8±0,2 versus 7,7±0,2 ml), la motilidad del semen (72,6±0,4 versus 67,4±0,7%), la actividad de masa (3,35±0,07 versus 2,52±0,08), la concentración de espermatozoides (982,2±67,8 versus 731,9±50,5 millones/ml), los espermatozoides vivos (80,1±0,3 versus 75,8±0,5%) y el nivel de testosterona sérica (4,02±0,21 versus 2,37±0,07 ng/ml), comparados con los animales controles. En el hemograma aumentaron los linfocitos (p<0,05) y disminuyeron variables como volumen corpuscular medio, recuento de leucocitos y tasa de neutrófilos (p<0,05). Hemoglobina, concentración de eritrocitos y hematocrito permanecieron inalterados. Todos los parámetros investigados se situaron dentro de los rangos normales para toros bubalinos. En conclusión, el tratamiento de búfalos Nili-Ravi con somatotropina mejoró la calidad del semen y aumentó la testosterona sérica, sin provocar ostensibles efectos adversos en el estado general de los toro

    Enhanced Polyhydroxybutyrate Production for Long-Term Spaceflight Applications

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    Synthetic biology holds the promise of advancing long term space fight by the production of medicine, food, materials, and energy. One such application of synthetic biology is the production of biomaterials, specifically polyhydroxyalkanoates (PHAs), using purposed organisms such as Escherichia coli. PHAs are a group of biodegradable bioplastics that are produced by a wide variety of naturally occurring microorganisms, mainly as an energy storage intermediate. PHAs have similar melting point to polypropylene and a Youngs modulus close to polystyrene. Due to limited resources and cost of transportation, large-scale extraction of biologically produced products in situ is extremely cumbersome during space flight. To that end, we are developing a secretion systems for exporting PHA from the cell in order to reduce unit operations. PHAs granules deposited inside bacteria are typically associated with proteins bound to the granule surface. Phasin, a granule bound protein, was targeted for type I secretion by fusion with HlyA signal peptide for indirect secretion of PHAs. In order to validate our secretion strategy, a green fluorescent protein (GFP) was tagged to the PHA polymerase enzyme (phaC), this three part gene cassette consists of phaA and phaB and are required for PHA production. Producing PHAs in situ during space flight or planet colonization will enable mission success by providing a valuable source of biomaterials that can have many potential applications thereby reducing resupply requirements. Biologically produced PHAs can be used in additive manufacturing such as three dimensional (3D) printing to create products that can be made on demand during space flight. After exceeding their lifetime, the PHAs could be melted and recycled back to 3D print other products. We will discuss some of our long term goals of this approach

    PREVALENCE AND ANTHELMINTIC EFFICACY OF ABAMECTIN AGAINST GASTROINTESTINAL PARASITES IN HORSES

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    The prevalence and anthelmintic efficacy of Abamectin against gastrointestinal parasites under field conditions in Faisalabad (Punjab, Pakistan) was studied in 100 horses. The overall prevalence of gastrointestinal parasites was 75%, including Strongylus spp. (50%), Oxyuris equi (12%), Parascaris equorum (8%) and mixed infection (5%). Among these naturally infected animals, 15 were selected. These horses were assigned to three groups on the basis of prevalent species of gastrointestinal parasites. Each group had five animals, comprising four treatment horses and a control horse. Abamectin was evaluated against these gastrointestinal parasites with a single shot at the dose rate of 0.2 mg/kg body weight administered through subcutaneous route which resulted in 98% reduction in faecal egg count after day 14 post-treatment. Non-treated horses remained positive for gastrointestinal parasites. No adverse reactions were observed during the experimental period. It was concluded that Abamectin is highly effective against gastrointestinal parasites in horses
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