1,412 research outputs found

    SOLON: An autonomous vehicle mission planner

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    The State-Operator Logic Machine (SOLON) Planner provides an architecture for effective real-time planning and replanning for an autonomous vehicle. The highlights of the system, which distinguish it from other AI-based planners that have been designed previously, are its hybrid application of state-driven control architecture and the use of both schematic representations and logic programming for the management of its knowledge base. SOLON is designed to provide multiple levels of planning for a single autonomous vehicle which is supplied with a skeletal, partially-specified mission plan at the outset of the vehicle's operations. This mission plan consists of a set of objectives, each of which will be decomposable by the planner into tasks. These tasks are themselves comparatively complex sets of actions which are executable by a conventional real-time control system which does not perform planning but which is capable of making adjustments or modifications to the provided tasks according to constraints and tolerances provided by the Planner. The current implementation of the SOLON is in the form of a real-time simulation of the Planner module of an Intelligent Vehicle Controller (IVC) on-board an autonomous underwater vehicle (AUV). The simulation is embedded within a larger simulator environment known as ICDS (Intelligent Controller Development System) operating on a Symbolics 3645/75 computer

    The connection between the papillary muscles and leaflets of the tricuspid valve

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    The tricuspid valve is more differentiated during evolutionary development than the mitral valve. In birds it is a muscular structure joined directly to the papillary muscles, although the mitral valve of birds resembles that of mammals. There have been well-known studies describing the evolutionary line of connection of the tricuspid valve with the papillary muscles. The present study was performed on a group of 107 formalin-fixed adult human hearts. The valves and papillary muscles were classified according to a scheme for human hearts drawn up earlier. The types of connection between leaflets of the tricuspid valve and the papillary muscles were classified according to a scheme drawn up earlier for vertebrates. We observed 3 types of connection between leaflets of the tricuspid valve and the papillary muscles in the group studied. The muscular and membranous connections were not linked with any one type of tricuspid valve. Atypical forms of distribution of the tendinous chords of the right ventricle were observed. It was found that valves with a higher number of leaflets were (with the exception of type 0) provided with a smaller number of tendinous chords. Atavistic features and atypical forms of distribution of the tendinous chords are present in a small percentage of samples of the human right valvular apparatus

    The morphology of the right atrioventricular valve in the adult human heart

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    Studies of the morphometry and normal anatomy of the tricuspid valve are in constant demand. Knowledge of the morphology of the normal tricuspid valve may be useful, for example in the context of the transfer of a leaflet of the tricuspid valve for repair or insufficiency of the mitral valve, in repair of the tricuspid valve after blunt chest trauma and in other surgical techniques of this region. In this study, performed in a group of 107 formalin-fixed adult human hearts, we attempted to assess the form and number of the main and accessory cusps in the tricuspid valve. Rare anatomical variants of the tricuspid valve were found. Using a planimeter we evaluated the surface area of the tricuspid valve and particular leaflets. With the help of a Vernier scale we measured the length and height of individual leaflets of the tricuspid valve and the length of the commissures. No differences were found between the length of the anterior and septal leaflets. The posterior leaflet was the shortest, while the anterior leaflet was the widest and had the largest surface area. The posterior leaflet was wider than the septal leaflet and had the smallest surface area. No differences were found between the main and accessory leaflets in the length of the commissures

    The morphology and distribution of the tendinous chords and their relation to the papillary muscles in the tricuspid valve of the human heart

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    The tendinous chords of the tricuspid valve are the predominant type of connection between the papillary muscles and the tricuspid valve. Studies describing the evolutionary line of these connections are well known. The flexibility of particular leaflets of the tricuspid valve varies, as does the tension of the blood stream in particular cusps. The present study was performed on a group of 96 formalin-fixed adult human hearts, which ranged in age from 18 to 90 years and gave no evidence of congenital malformations or pathological changes. The valves were divided into five types according to earlier studies and analysis was made in terms of these types. The tendinous chords and their ramifications were counted. The surfaces of particular leaflets were measured. The ratio of marginal to ventricular leaflets was counted for each type of leaflet in particular types of valves. The parts of the main leaflets supported by specific papillary muscles were counted for types 1, 2 and 3. The number of tendinous chords decreased in leaflets in particular types of tricuspid valve, but the ratio of chords attached to the margins and ventricular surfaces was similar. The number of chords for the surface of leaflets (measured in mm2) was similar in particular types of valve for all cusps. The most differentiated were commissural chords in all types of valve. The ratio of chords attached to the margins and ventricular surfaces does not depend on the surface area of the leaflets

    Microscopic study of right fibrous annulus

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    The term annulus fibrous is still used in anatomical and clinical terminology but does not exist in anatomical nomenclature. This structure is proposed as an anatomical substrate for circus movement of excitation. Multiple cardiac damage after blunt chest trauma is rare, but usually affects the septal part of the right fibrous annulus. Histological observation confirms the results of our previous macroscopic study and shows that the most stable part of fibrous annulus is the septal part and the region of anterior angle of the right ventricle, and the most labile parts are the lateral and posterior angles of the right ventricle and the posterior part of the fibrous annulus. Our histological study shows that the right fibrous annulus is a heterogeneous structure and may play a role in changes of shape of the right atrio-ventricular ostium during human life

    The relationship between the membranous part of the interventricular septum and the septal part of the attachment of the tricuspid valve in adult human hearts

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    The membranous septum is a difficult structure to demonstrate in vivo. It is possible to measure its dimensions in a cadaver after the introduction of light into the aorta, but difficult to do so otherwise. The present study was performed on a group of 107 formalin-fixed adult hearts from both sexes and 18-90 years of age. The hearts were divided into groups depending on sex and age. The length of the septal part of the attachment of the tricuspid valve was divided by the length of the supravalvular part of the membranous interventricular septum

    Morphometric features of the right atrioventricular orifice in adult human hearts

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    The normal data of the tricuspid valve complex is of great clinical importance in the light of progress in cardiosurgery and the development of novel operating techniques. A range of measurements for the right atrioventricular orifice in 96 human adult hearts was examined by means of anatomical dissection, inspection, examination, and statistical analyses. The length of the attachment of the anterior leaflet increased significantly between group I (aged 18-40 years) and group II (aged 41-64 years) in women only. In men there were no significant differences in this parameter between any of the three age groups. In addition, the attachment length of the posterior leaflet in women increased statistically in the second age group. In men, in contrast, the attachment length of the posterior leaflet did not increase significantly between the first and second age groups and became significantly larger only in oldest age group, consisting of men aged over 65. No statistically significant differences between the three age groups were found for the attachment length of the septal leaflet (p > 0.05). In female hearts significant increases in the frontal and sagittal dimensions of the tricuspid valve orifice were observed between the second age group and the group aged over 65. In male hearts both the frontal and sagittal dimensions increased significantly with advanced age. The right atrioventricular orifice expressed as the ellipse area was statistically greater than the triangular area (p < 0.01) in each age group. It should be noticed that both areas increased significantly during ageing. This study has demonstrated that the shape of the right atrioventricular orifice evolves during life, from a triangular shape to a more elliptical shape. (Folia Morphol 2008; 67: 53-57

    The morphometry of the accessory leaflets of the tricuspid valve in a four cuspidal model

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    The tricuspid valve is of great importance because of the progress made in operative techniques and invasive cardiology accidents. This structure is more differentiated during evolution than the mitral valve. Accessory leaflets, their frequency and role are still controversial, despite the fact that they have been known from the beginning of the 20th century. The number of leaflets in the tricuspid valve grows in an evolutionary line, but the rules governing their appearance are still not known. The samples were taken from a group of 107 human adult hearts. The four-cuspidal form of the tricuspid valve was used as the simplest model to show the appearance of accessory leaflets for anatomical and statistical examination. On the basis of the results of this study we conclude that the separation of accessory leaflets is a complex process

    Left ventricular false tendons: echocardiographic characteristics in the Polish population

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    Background: False tendon (FT) is described in a wide range (40% to 62%) of the examined hearts depending on age and additional heart abnormalities. On echocardiography, the range is even wider (1.6–78%), depending on study design and inclusion criteria. Ultrasonographic characteristics of left ventricular FTs in the Polish population are not well known. Materials and methods: Echocardiographic examinations of 1,679 consecutive patients were evaluated. All cases were classified according to American Society of Echocardiography Committee of Nomenclature and Standards Document on Identification of the Segments of the Heart Muscle. Results: In our study, fibrous structures in the lumen of the left ventricle were detected in 100 (6%) subjects of the study group. The age of the subjects ranged from 16 to 87 years (mean age 47.9), 50 were males and 50 were females. In 94% of the subjects, FT was a single structure. No patient had clinically evident arrhythmia. Conclusions: In the Polish population, FT can be identified in all age groups, and the prevalence is similar to that reported in the literature

    Lung and Intercostal Upper Abdomen Ultrasonography for Staging Patients with Ovarian Cancer: A Method Description and Feasibility Study

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    A detailed transabdominal and transvaginal ultrasound examination, performed by an expert examiner, could render a similar diagnostic performance to computed tomography for assessing pelvic/abdominal tumor spread disease in women with epithelial ovarian cancer (EOC). This study aimed to describe and assess the feasibility of lung and intercostal upper abdomen ultrasonography as pretreatment imaging of EOC metastases of supradiaphragmatic and subdiaphragmatic areas. A preoperative ultrasound examination of consecutive patients suspected of having EOC was prospectively performed using transvaginal, transabdominal, and intercostal lung and upper abdomen ultrasonography. A surgical-pathological examination was the reference standard to ultrasonography. Among 77 patients with histologically proven EOC, supradiaphragmatic disease was detected in 13 cases: pleural effusions on the right (n = 12) and left (n = 8) sides, nodular lesions on diaphragmatic pleura (n = 9), focal lesion in lung parenchyma (n = 1), and enlarged cardiophrenic lymph nodes (n = 1). Performance (described with area under the curve) of combined transabdominal and intercostal upper abdomen ultrasonography for subdiaphragmatic areas (n = 77) included the right and left diaphragm peritoneum (0.754 and 0.575 respectively), spleen hilum (0.924), hepatic hilum (0.701), and liver and spleen parenchyma (0.993 and 1.0 respectively). It was not possible to evaluate the performance of lung ultrasonography for supradiaphragmatic disease because only some patients had this region surgically explored. Preoperative lung and intercostal upper abdomen ultrasonography performed in patients with EOC can add valuable information for supradiaphragmatic and subdiaphragmatic regions. A reliable reference standard to test method performance is an area of future research. A multidisciplinary approach to ovarian cancer utilizing lung ultrasonography may assist in clinical decision-making.info:eu-repo/semantics/publishedVersio
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