Analysis of the high-speed rotary motion of a superconducting magnetic bearing during ring spinning

Ring spinning is the leading textile technology for the production of short staple yarn, which runs commercially up to a maximum speed of 25 000 rpm. Higher speeds result in yarn damage mainly due to frictional heat. To eliminate this limitation, a friction-free superconducting magnetic bearing (SMB) was introduced as alternative high-speed yarn twist element consisting of a cryostat with an array of superconductors and a levitating permanent magnet ring with a yarn guide. Whereas stable spinning was possible until 30 000 rpm, it turned out that the new SMB twist element is more susceptible to external disturbances resulting in oscillating movements of the magnet. Therefore, a measurement system with an array of 5 synchronized optical laser triangulation sensors and one tachometer was implemented to analyse this motion in detail during spinning with high speeds. To test the system, the spinning speed was varied between 10 000 rpm and 21 000 rpm for different yarn qualities. In general, the magnetic ring oscillates around its centre position with the rotation frequency and a peak amplitude between 10 μm and 14 μm, which might be due to a small imbalance of the magnet. At the same time, the small tilt of the ring remained fixed with respect to the machine for all speeds. In addition, larger oscillation amplitudes of up to 300 μm are observed at 18 Hz for selected spinning parameters arising most probably from resonance effects with machine vibrations

Hyperperfusion Syndrome After MCA Embolectomy - a rare complication?

Patient: Female, 78 Final Diagnosis: Cerebral hyperperfusion syndrome Symptoms: — Medication: — Clinical Procedure: Endovascular embolectomy Specialty: Neurology Objective: Unknown ethiology Background: Cerebral hyperperfusion syndrome (cHS) is a well known but rare complication after carotid endarterectomy, carotid angioplasty with stenting, and stenting of intracranial arterial stenosis. The clinical presentation may vary from acute onset of focal oedema (stroke-like presentation) and intracerbral hemorrhage to delayed (>24h hours after the procedure) presentation with seizures, focal motor weakness, or late intracerebral hemorrhage. The incidence of cHS after carotid endarterectomy ranges from 0–3% and defined as an increase of the ipsilateral cerebral blood flow up to 40% over baseline in ultrasound. Case Report: We present a case of a 78-year-old woman with an acute ischemic stroke due to left side middle cerebral artery territory with right sided hemiparesis and aphasia (NIHSS 16). After systemic thrombolysis embolectomy using a retractable stent (Solitaire® device) was performed and resulted in complete and successful recanalization of MCA including its branches about 210 minutes after symptom onset but, partial dislocation of thrombotic material into the anterior cerebral artery (ACA). Conclusions: Cerebral hyperperfusion syndrome should be considered in patients with clinical deterioration after successful recanalisation and the early diagnosis and treatment may be important for neurological outcome after endovascular embolectomy Keywords: embolectomy, hyperperfusion syndrome, ischemic stroke, middle cerebral artery occlusio

Isoflurane in (Super-) Refractory Status Epilepticus: A Multicenter Evaluation

Background We aimed to determine the association between seizure termination and side effects of isoflurane for the treatment of refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) in neurointensive care units (neuro-ICUs). Methods This was a multicenter retrospective study of patients with RSE/SRSE treated with isoflurane for status epilepticus termination admitted to the neuro-ICUs of nine German university centers during 2011–2018. Results We identified 45 patients who received isoflurane for the treatment of RSE/SRSE. During isoflurane treatment, electroencephalograms showed no epileptiform discharges in 33 of 41 (80%) patients, and burst suppression pattern was achieved in 29 of 41 patients (71%). RSE/SRSE was finally terminated after treatment with isoflurane in 23 of 45 patients (51%) for the entire group and in 13 of 45 patients (29%) without additional therapy. Lengths of stay in the hospital and in the neuro-ICU were significantly extended in cases of ongoing status epilepticus under isoflurane treatment (p = 0.01 for length of stay in the hospital, p = 0.049 for length in the neuro-ICU). During isoflurane treatment, side effects were reported in 40 of 45 patients (89%) and mainly included hypotension (n = 40, 89%) and/or infection (n = 20, 44%). Whether side effects occurred did not affect the outcome at discharge. Of 22 patients with follow-up magnetic resonance imaging, 2 patients (9%) showed progressive magnetic resonance imaging alterations that were considered to be potentially associated with RSE/SRSE itself or with isoflurane therapy. Conclusions Isoflurane was associated with a good effect in stopping RSE/SRSE. Nevertheless, establishing remission remained difficult. Side effects were common but without effect on the outcome at discharge

Fulminant Acute Ascending Hemorrhagic Myelitis Treated with Eculizumab

We describe an 18-year-old patient who developed back pain, rapidly ascending sensomotory deficits, bladder dysfunction, Lhermitte's sign, absent abdominal reflexes of all three levels, brisk tendon reflexes, and positive Babinski's sign. Magnetic resonance imaging of the spinal cord showed a long segment of cervical and thoracic intramedullary signal hyperintensity suggesting a longitudinally extensive transverse myelitis possibly within the course of a fast progressing ascending immune-mediated hemorrhagic myelopathy. Throughout his illness, the patient deteriorated with tetraplegia, cardiac arrest, and respiratory failure although he received, after exclusion of infective causes, therapy with steroids, immunoglobulins, plasmapheresis, and cyclophosphamide. Interestingly, treatment with the C5-inhibitor eculizumab to prevent complement-mediated spinal cord injury achieved an arrest of clinical deterioration. We propose eculizumab as treatment in fast progressive and potentially fatal immune-mediated spinal cord injury. Furthermore, this case raises awareness for the process of clinical decision-making in severe myelopathies

Influence of the magnet aspect ratio on the dynamic stiffness of a rotating superconducting magnetic bearing

Rotating superconducting bearings promise great potential in applications due to their frictionless operation. However, these bearings show a lower dynamic stiffness and damping coefficient compared to ball bearings. In this paper we studied a bearing consisting of a fixed YBCO ring and a rotating magnet above the superconductor. The influence of the magnet aspect ratio on the dynamic stiffness of the bearing was investigated in order to find an optimized size. To change the aspect ratio, we kept the inner diameter of the ring constant and reduced the outer diameter while increasing the ring height. In addition to these magnets, one magnet with a reduced cross-sectional area was studied. The aspect ratio selection was based on preliminary magnetic flux density simulations, which compared the magnetic flux density distribution and the potential radial force for different aspect ratios. To conduct the measurements, the field-cooled magnets were displaced in a lateral direction and then released, resulting in a damped oscillation. The dynamic stiffness constants were calculated for each bearing from the relation of three axis acceleration measurements for different field cooling heights. The comparison of the stiffness constants for the different bearings revealed an optimal aspect ratio for the given YBCO ring. This optimum is almost independent from the cooling height. The comparison between the two magnet rings with similar diameters and different heights was similar for the bearing characteristics at a low cooling height, whereas a significant reduction of stiffness was observed with a larger cooling distance. The difference is bigger for the magnet with a reduced height. The optimal aspect ratio as well as the stiffness dependence on the cross-sectional area was confirmed by simulations of the magnetic flux density distribution. © 2019 IOP Publishing Ltd

Motility analysis by means of video tracked markers

The motility of the gastrointestinal tract is crucial for digestive activity and dysfunction can lead to severe disease pattern. A method for analysing the motility is needed when treatment approaches shall be evaluated. Therefore markers attached to different locations on the stomach and the bowel of pigs are video tracked in this research study. The markers are designed to provide a high contrast and have an adhesive side for fixation. Above the operation field a video camera has been placed to film the markers during the procedure. To analyse the video data a special algorithm has been implemented. The algorithm requires a registration process at the beginning of each recording which allows the parallel tracking of multiple markers. After the registration the algorithm tracks the position of the marker frame by frame. Each frame is converted into a greyscale picture by adding specified colour values of each pixel. This allows emphasizing certain colours. The centre of the marker is determined by computing the horizontal and vertical centre of the marker starting at the corresponding marker position of the previous frame. After completion the data is stored as coordinates and a video with the marker position displayed for further processing. For advanced analysis the data can be synchronized with electromyography signals, for example. The marked videos show a promising tracking of the markers. However, if the algorithm loses track of a marker during a recording, it is unlikely to relocate it due to the successive processing of the frames. Nevertheless this method provides a simple and easy to use solution for movement detection of the gastrointestinal tract

Colistin- and carbapenem-resistant Klebsiella oxytoca harboring blaVIM-2 and an insertion in the mgrB gene isolated from blood culture

A carbapenemase-producing colistin-resistant Klebsiella oxytoca isolate was recovered from a blood culture of a female patient without previous report of risk factors to obtain multidrug-resistant Gram-negative bacilli. A combination of biochemical and molecular methods was used to identify the resistance mechanism of this isolate. Carbapenemase production was mediated by Verona integron-encoded metallo-S-lactamase (VIM)-2. Colistin resistance was not due to plasmid- borne mcr-1 gene, but we found an integration of IS5-like sequence in the mgrB gene of K. oxytoca. This gene is known to be an important regulator of the PhoPQtwo-component system, and the disruption of this gene is most likely the cause of lipid A modification resulting in colistin resistance of our isolate. To the best of our knowledge this constitutes the first report of a carbapenemase-producing K. oxytoca with colistin resistance, a case that demonstrates the limited treatment options for infections with multidrug-resistant organisms. (C) 2017 Elsevier GmbH. All rights reserved