An electrical circuit theoretical method for time- and frequency-domain solutions of the structural mechanics problems

Shrinking device dimensions in integrated circuit technology made integrated circuits with millions of components a reality. As a result of this advance, electrical circuit simulators that can handle very large number of components have emerged. These programs use new circuit simulation techniques and can find solutions accurately and quickly. In this paper, we apply these techniques to structural mechanics problems by adopting electrical circuit equivalents. We first apply finite element formulation to the mechanical problem. The obtained sets of equations are treated as if they are sets of equations of an equivalent electrical circuit which consists of linear circuit elements such as capacitors, inductors and controlled sources. The equivalent circuit is obtained in the form of a circuit netlist and solved using a general purpose electrical circuit simulator. Several examples showing the advantages of the circuit simulation techniques are demonstrated. Asymptotic waveform evaluation technique which is widely used for simulation of large electrical circuits is also studied for the same examples and the speed-up advantage is shown. Copyright © 1999 John Wiley & Sons, Ltd

Anomalous Hopping Exponents of Ultrathin Films of Metals

The temperature dependence of the resistance R(T) of ultrathin quench-condensed films of Ag, Bi, Pb and Pd has been investigated. In the most resistive films, R(T)=Roexp(To/T)^x, where x=0.75. Surprisingly, the exponent x was found to be constant for a wide range of Ro and To in all four materials, possibly implying a consistent underlying conduction mechanism. The results are discussed in terms of several different models of hopping conduction.Comment: 6 pages, 5 figure

Bilateral ischemic lumbosacral plexopathy presenting as acute paraparesia due to vascular graft occlusion in a patient with leriche syndrome [Leriche sendromlu bir olguda vasküler greft oklüzyonu sonucu akut paraparezi Şeklinde prezente olan bilateral ıskemik lumbosakral pleksopati]

Acute ischemia of peripheral nerves generally results from occlusion of a main proximal limb artery or from occlusion of many distal arteries. The rareness of such neuropathies can be explained by the relative resistance of peripheral nerves to ischemia. Leriche syndrome is an aortoiliac occlusive disease that is known to cause neurologic complications such as ischemic neuropathy and spinal cord ischemia. Here, we present a man aged 55 years with bilateral lumbosacral plexopathy that presented as acute paraparesia due to thrombotic occlusion of an axillobifemoral graft, which was performed for the treatment of Leriche syndrome. © 2017, Ege University Press. All rights reserved

Stronger Together? Tourists’ Behavioral Responses to Joint Brand Advertising

© Copyright © 2020, American Academy of Advertising. Drawing on collaboration theory, this research investigates the effect of joint versus single brand advertising on tourists’ behavioral responses with two experiments. Study 1 employs a field experiment to examine the effect of joint brand advertising on tourists’ actual information search behavior. Study 2 uses a laboratory experiment to investigate the effect of joint brand advertising on tourists’ intention to visit a destination and measures whether this relationship is mediated by product interest. Study 1 suggests that, compared to single brand advertising, joint brand advertising increases tourists’ search behavior. Study 2 shows that joint brand advertising stimulates product interest, which in turn increases tourists’ intention to visit. The mediating role of product interest disappears when a destination brand forms a partnership with a lesser-reputed travel intermediary brand. The research provides implications for theory development in the area of tourism advertising, while also identifying best practices for advertisers on how to optimize the effectiveness of their campaigns

Evaluation of saccadic and smooth pursuit eye movements at an early stage of essential tremor [Esansiyel tremor erken döneminde sakkadik ve yavaş göz hareketlerinin değerlendirilmesi]

Objectives: Though still unclear cerebellar involvement is accepted as the underlying pathophysiological mechanism of at least advanced stages of essential tremor (ET). Eye movement abnormalities supporting this hypothesis have been reported. We tried to investigate saccadic and pursuit eye movements in ET patients at an early stage of the disease (mean disease duration 20.35 ± 10.51 months). Materials and Methods: Binocular horizontal saccadic and pursuit eye movements were recorded by using a video-based eye tracker in 25 patients with ET and 16 age matched controls. For the saccades peak saccadic velocity, latency and accuracy and for pursuit eye movements gain at three different target velocities (0.1, 0.2 and 0.4 Hz) was taken into consideration. Results: Peak saccadic latency, velocity and accuracy values recorded from the patients during saccadic eye movements were compared with the values gathered from the healthy controls revealing no significant difference (p>0.05). The same was true for pursuit eye movements. Pursuit gain at three different target velocities recorded from ET patients were not statistically different from the healthy controls (p>0.05). Conclusion: Normal eye movements at the early stage of the disease may indicate cerebellar dysfunction to be a late feature of ET. The other explanation can be the heterogeneous nature of the disease, those with abnormal eye findings representing a specific pathological subset. © 2016, Ege University Press. All rights reserved

Diagnostic value of cauda equina motor conduction time in lumbar spinal stenosis

PubMed ID: 22418591Objective: Lumbar spinal stenosis (LSS) is a chronic degenerative disease with pain in the back, buttocks and legs aggrevated by walking and relieved after rest without associated vascular disease of lower extremities observed in patients between 50 and 60. years. Several studies, using different methods indicated an association between slowing or blocking of root-nerve conduction and LSS. None of the previous research had applied the more conceivable methods such as recording the cauda equina potentials from the lumbar level or stimulating the spinal roots within the canal using either leg nerves or muscles. In this study, electrical lumbar laminar stimulation was used to demonstrate prolongation of cauda equina motor conduction time in lumbar spinal stenosis. Methods: Twenty-one LSS patients and age matched 15 normal control subjects were included in the study. Lumbar laminar electrical stimulation from L1 and L5 vertebra levels were applied by needle electrodes. Compound muscle action potential (CMAP) from gastrocnemius muscles were recorded bilaterally. Latency difference of CMAPs obtained from L1 and L5 spine levels were accepted as the cauda equina motor conduction time (CEMCT). Results: CEMCT was significantly longer in patient group when compared to normal controls. Mean latency difference was 3.59 ± 1.07. msec on the right side, 3.49 ± 1.07. msec on the left side in LSS group, it was 1.45 ± 0.65. msec on the right side, 1.35 ± 0.68. msec on the left side on normal control group (p< 0.0001). Conclusions: The prolongation of CEMCT was statistically and individually significant in patient group. This may indicate that lower lumbosacral motor roots were locally and chronically compressed due to lumbar spinal stenosis. Lumbar spinal stenosis may have induced local demyelination at the cauda equina level. Significance: Since the prolongation of CEMCT was found only in patients with LSS, the method of laminar stimulation can be chosen for patients with uncertain diagnosis of LSS. © 2012 International Federation of Clinical Neurophysiology