Магнитоэлектрический двигатель для привода рулевой колонки автотранспортного средства

Научная квалификационная работа посещена исследованию пульсаций электромагнитного момента в магнитоэлектрическом двигателе рулевой колонки автотранспортного средства. В первой главе выполнен обзор исследований на тему магнитоэлектрических машин с различной компоновкой магнитов на роторе и осуществлена постановка задачи научной квалификационной работы. Во второй главе рассмотрены вопросы имитационного моделирования магнитоэлектрической машины в конечно-элементной компьютерной среде. Выполнено планирование эксперимента, получена взаимосвязь между количеством пазов ротора, зубцами статора, коэрцитивной силы магнитов с позиции значений электромагнитного момента. В третьей главе выполнен расчет связанной модели магнитоэлектрический двигатель-инвертор напряжения-система управления.Scientific qualification work is visited to a research of pulsations of the electromagnetic torque in the magnetoelectric motor of a steering column of the vehicle. In chapter 1 the review of researches on magnetoelectric machine with various configuration of magnets on a rotor is executed and problem definition of scientific qualification work is carried out. In chapter 2 questions of a simulation modeling of the magnetoelectric machine in the terminating and element computer environment are considered. Scheduling of an experiment is executed, the interrelation between quantity of poles of a rotor, tooths of a stator, a coercive force of magnets from a position of values of the electromagnetic torque is received. In a chapter 3 calculation of the bound model the magnetoelectric motor

The History of Stereotactic and Functional Neurosurgery in Zurich

Zurich's stereotactic and functional neurosurgery (SFN) has a rich legacy beginning with the studies of the physiologist and Nobel prize winner Walter Rudolf Hess over the efforts of the neurosurgeons Hugo Krayenbühl and Mahmut Gazi Yaşargil up to the work of the functional surgeon Jean Siegfried and the modern era of SFN and neuromodulation. A comprehensive review and synthesis of data acquired from institutional archives and personal interviews as well as from journal articles, included references, proceedings of scientific meetings, staff biographies, and book publications were performed to gain insight into Zurich's long journey toward contemporary SFN and to highlight its stereotactic and functional history with special reference to the development of deep brain stimulation. Zurich's history of medicine includes decisive moments for the fundamentals and development of SFN. After an early period of innovation and research later followed by a long time of clinical application during the 20th century, it became quieter at the turn of the century. Since the end of the 2000s, an impressive renaissance occurred in Zurich that revived its rich SFN tradition

An unexpected intracerebral lesion - case report of a superinfected aspergillosis mimicking a brain metastasis

BACKGROUND: Invasive aspergillosis of the central nervous system is a rare but increasingly prevalent disease. We present the unusual case of an immunosuppressed patient suffering from unexpected superinfected invasive aspergillosis with cerebral, pulmonal, and adrenal manifestations, mimicking a metastasized bronchial carcinoma. This report reveals the importance of including aspergillosis in the differential diagnosis of a cerebral mass lesion in the light of unspecific clinical findings. CASE PRESENTATION: A 58-year-old immunocompromised female presented to our emergency department with a single tonic-clonic seizure. Imaging showed a ring enhancing cerebral mass with perifocal edema and evidence of two smaller additional hemorrhagic cerebral lesions. In the setting of a mass lesion in the lung, and additional nodular lesions in the left adrenal gland the diagnosis of a metastasized bronchus carcinoma was suspected and the cerebral mass resected. However, histology did not reveal any evidence for a neoplastic lesion but septate hyphae consistent with aspergillus instead and microbiological cultures confirmed concomitant staphylococcal infection. CONCLUSIONS: A high index of suspicion for aspergillus infection should be maintained in the setting of immunosuppression. Clinical and radiological findings are often unspecific and even misleading. Definite confirmation usually relies on tissue diagnosis with histochemical stains. Surgical resection is crucial for establishing the diagnosis and guiding therapy with targeted antifungal medications

Influence of head-over-body and body-over-head posture on craniospinal, vascular, and abdominal pressures in an acute ovine in-vivo model

INTRODUCTION Optimal shunt-based hydrocephalus treatments are heavily influenced by dynamic pressure behaviors between proximal and distal ends of shunt catheters. Posture-dependent craniospinal, arterial, venous, and abdominal dynamics thereby play an essential role. METHODS An in-vivo ovine trial (n = 6) was conducted to evaluate communication between craniospinal, arterial, venous, and abdominal dynamics. Tilt-testing was performed between -13° and + 13° at 10-min intervals starting and ending at 0° prone position. Mean pressure, pulse pressure, and Pearson correlation (r) to the respective angle were calculated. Correlations are defined as strong: |r|≥ 0.7, mild: 0.3 <|r|< 0.7, and weak: |r|≤ 0.3. Transfer functions (TFs) between the arterial and adjacent compartments were derived. RESULTS Strong correlations were observed between posture and: mean carotid/femoral arterial (r = - 0.97, r = - 0.87), intracranial, intrathecal (r = - 0.98, r = 0.94), jugular (r = - 0.95), abdominal cranial, dorsal, caudal, and intravesical pressure (r = - 0.83, r = 0.84, r = - 0.73, r = 0.99) while mildly positive correlation exists between tilt and central venous pressure (r = 0.65). Only dorsal abdominal pulse pressure yielded a significant correlation to tilt (r = 0.21). TFs followed general lowpass behaviors with resonant peaks at 4.2 ± 0.4 and 11.5 ± 1.5 Hz followed by a mean roll-off of - 15.9 ± 6.0 dB/decade. CONCLUSIONS Tilt-tests with multi-compartmental recordings help elucidate craniospinal, arterial, venous, and abdominal dynamics, which is essential to optimize shunt-based therapy. Results motivate hydrostatic influences on mean pressure, with all pressures correlating to posture, with little influence on pulse pressure. TF results quantify the craniospinal, arterial, venous, and abdominal compartments as compliant systems and help pave the road for better quantitative models of the interaction between the craniospinal and adjacent spaces

The Sheep as a Comprehensive Animal Model to Investigate Interdependent Physiological Pressure Propagation and Multiparameter Influence on Cerebrospinal Fluid Dynamics

The present study aims to develop a suitable animal model for evaluating the physiological interactions between cerebrospinal fluid (CSF) dynamics, hemodynamics, and abdominal compartment pressures. We seek to contribute to the enhanced recognition of the pathophysiology of CSF-dependent neurological disorders like hydrocephalus and the improvement of available treatment options. To date, no comprehensive animal model of CSF dynamics exists, and establishing an accurate model will advance our understanding of complex CSF physiology. Persisting knowledge gaps surrounding the communication and pressure propagation between the cerebrospinal space and adjacent anatomical compartments exacerbate the development of novel therapies for neurological diseases. Hence, the need for further investigation of the interactions of vascular, craniospinal, and abdominal pressures remains beyond dispute. Moreover, the results of this animal study support the optimization of in vitro test benches for medical device development, e.g., ventriculoperitoneal shunts. Six female white alpine sheep were surgically equipped with pressure sensors to investigate the physiological values of intracranial, intrathecal, arterial, central venous, jugular venous, vesical pressure, and four differently located abdominal pressures. These values were measured simultaneously during the acute animal trial with sheep under general anesthesia. Both carotid and femoral arterial blood pressure indicate a reliable and comparable representation of the systematic blood pressure. However, the jugular venous pressure and the central venous pressure in sheep in dorsal recumbency do not correlate well under general anesthesia. Furthermore, there is a trend for possible comparability of lateral intraventricular and lumbar intrathecal pressure. Nevertheless, animal body position during measurements must be considered since different body constitutions can alter the horizontal line between the cerebral ventricles and the lumbar subarachnoid space. While intra-abdominal pressure measurement in the four different abdominal quadrants yielded greater inter-individual variability, intra-vesical pressure measurements in our setting delivered comparable values for all sheep. We established a novel and comprehensive ovine animal model to investigate interdependent physiologic pressure propagation and multiparameter influences on CSF dynamics. The results of this study will contribute to further in vitro bench testing, the derivation of novel quantitative models, and the development of a pathologic ovine hydrocephalus model

Venous dynamics in anesthetized sheep govern postural-induced changes in cerebrospinal fluid pressure comparable to those in humans

Sheep are popular large animals in which to model human disorders and to study physiological processes such as cerebrospinal fluid dynamics. However, little is known about vascular compensatory mechanisms affecting cerebrospinal fluid pressures during acute postural changes in sheep. Six female white Alpine sheep were anesthetized to investigate the interactions of the vascular and cerebrospinal fluid system by acquiring measurements of intracranial pressure and central and jugular venous pressure during passive postural changes induced by a tilt table. The cross-sectional area of the common jugular vein and venous blood flow velocity was recorded. Anesthetized sheep showed bi-phasic effects of postural changes on intracranial pressure during tilting. A marked collapse of the jugular vein was observed during head-over-body tilting; this is in accordance with findings in humans. Active regulatory effects of the arterial system on maintaining cerebral perfusion pressure were observed independent of tilting direction. Conclusion: Anesthetized sheep show venous dynamics in response to posture-induced changes in intracranial pressure that are comparable with those in humans