Tunable asymmetric spin wave excitation and propagation in a magnetic system with two rectangular blocks

Asymmetric spin wave excitation and propagation are key properties to develop spin-based electronics, such as magnetic memory, spin information and logic devices. To date, such nonreciprocal effects cannot be manipulated in a system because of the geometrical magnetic configuration, while large values of asymmetry ratio are achieved. In this study, we suggest a new magnetic system with two blocks, in which the asymmetric intensity ratio can be changed between 0.276 and 1.43 by adjusting the excitation frequency between 7.8 GHz and 9.4 GHz. Because the two blocks have different widths, they have their own spin wave excitation frequency ranges. Indeed, the spin wave intensities in the two blocks, detected by the Brillouin light scattering spectrum, were observed to be frequency-dependent, yielding tuneable asymmetry ratio. Thus, this study provides a new path to enhance the application of spin waves in spin-based electronics.

Optimum design for the ballistic diode based on graphene field-effect transistors

We investigate the transport behavior of two-terminal graphene ballistic devices with bias voltages up to a few volts suitable for electronics applications. Four graphene devices based ballistic designs, specially fabricated from mechanically exfoliated graphene encapsulated by hexagonal boron nitride, exhibit strong nonlinear I-V characteristic curves at room temperature. A maximum asymmetry ratio of 1.58 is achieved at a current of 60 µA at room temperature through the ballistic behavior is limited by the thermal effect at higher bias. An analytical model using a specular reflection mechanism of particles is demonstrated to simulate the specular reflection of carriers from graphene edges in the ballistic regime. The overall trend of the asymmetry ratio depending on the geometry fits reasonably with the analytical model.

A Novel Interior Permanent Magnet Machine with Magnet Axis Shifted Effect for Electric Vehicle Applications

This paper proposes a novel interior permanent magnet (IPM) machine with asymmetrical PM configuration. Different from the traditional IPM counterparts, the proposed machine can perform a magnet axis shifted (MAS) effect. The magnet axis is shifted towards the reluctance axis so that a higher resultant torque capability can be obtained. Firstly, the configuration and the basic principle of the proposed machine are described. The design parameters are optimized to improve the torque capability, and the effect of the PM asymmetry ratio on the torque performance is then evaluated in detail. In addition, the major electromagnetic characteristics of the optimized machine are investigated and compared with those of the Prius 2010 IPM machine by finite element method (FEM). The results demonstrate that the proposed asymmetrical PM configuration can achieve the torque improvement due to the MAS effect.

Effects of Menstrual Cycles on VOR Gain Functions

Purpose The aim of the present study was to assess the vestibuloocular reflex (VOR) gain function and VOR gain asymmetry during the various phases of the menstrual cycle in young healthy female participants. The study also aimed to characterize the presence or absence of corrective saccades during the various phases of the menstrual cycle. Method Twenty-nine young healthy females participated in the study. The video head impulse test (vHIT) was performed in lateral, left anterior right posterior, and right anterior left posterior plane during the various phases of the menstrual cycle to see the changes in VOR gain function and VOR gain asymmetry ratio changes. Results A repeated measure analysis of variance test did not show any significant main effect for the VOR gain function and VOR gain asymmetry ratio in various phases of the menstrual cycle in all the participants. The result suggested no changes in VOR gain function and VOR asymmetry ratio in healthy females during the menstrual cycle. Also, there was an absence of saccades in the entire participants group during the various phases of the menstrual cycle. Conclusions As the VOR gain function does not change during the various phases of the menstrual cycle in young healthy females, there is no need to consider the various phases of the menstrual cycle while testing any female participant during the vHIT test.

Tone Burst Masseter Vestibular Evoked Myogenic Potentials: Normative Values and Test–Retest Reliability

Background Masseter vestibular evoked myogenic potential (mVEMP) is a recent tool for the assessment of vestibular and trigeminal pathways. Though a few studies have recorded mVEMP using click stimuli, there are no reports of these potentials using the more conventional VEMP eliciting stimuli, the tone bursts. Purpose The aim of the study is to establish normative values and determine the test–retest reliability of tone burst evoked mVEMP. Research Design The research design type is normative study design. Study Sample Forty-four healthy participants without hearing and vestibular deficits in the age range of 18 to 50 years participated in the study. Data Collection and Analysis All participants underwent mVEMP testing using 500 Hz tone-burst stimuli at 125 dB peSPL. Ten participants underwent second mVEMP testing within 1 month of the initial testing to estimate the test–retest reliability. Results Tone burst mVEMP showed robust responses in all participants. There were no significant ear and sex differences on any mVEMP parameter (p > 0.05); however, males had significantly higher EMG normalized peak-to-peak amplitude than females. Intraclass correlation coefficient (ICC) values of tone burst mVEMP showed excellent test–retest reliability (ICC >0.75) for ipsilateral and contralateral p11 latency, ipsilateral EMG normalized p11-n21 peak to peak amplitude, and amplitude asymmetry ratio. Fair and good test–retest reliability (0.4 < ICC > 0.75) was observed for ipsilateral and contralateral n21 latency, contralateral EMG normalized peak-to-peak amplitude, and amplitude asymmetry ratio. Conclusion Tone burst mVEMP is a robust and reliable test for evaluating the functional integrity of the vestibulomasseteric reflex pathway.

Independent Measures of Utricular Function: Ocular Vestibular Evoked Myogenic Potentials Do Not Correlate With Subjective Visual Vertical or Fundus Photographic Binocular Cyclorotation

Ocular vestibular evoked myogenic potentials (oVEMPs), subjective visual vertical (SVV), and fundus photographically measured binocular cyclorotation (BCR) are diagnostic tests to assess utricular function in patients with vertigo or dizziness. In 138 patients with chronic vertigo or dizziness, we asked whether the asymmetry ratio of oVEMP (normal, right side pathological, left side pathological) could predict the SVV deviation (normal, rightward deviation, leftward deviation) or BCR (normal, cyclorotation to the right, cyclorotation to the left). There was no correlation between oVEMP and SVV and between oVEMP and BCR, while SVV and BCR correlated highly. Although both oVEMP and SVV measure aspects of utricular function, our findings demonstrate that oVEMP and SVV are not redundant and may reflect different utricular pathologies. The role of fundus photographic BCR may be relegated to only confirm unclear SVV results in vestibular diagnostic workup.

The aging-related decrease in cVEMP amplitude cannot be accounted for by normalization

BACKGROUND: Cervical Vestibular Evoked Myogenic Potentials (cVEMP) is an electromyogenic measure commonly used in clinic to assess saccule function. The main parameters are peak-peak amplitude and interaural asymmetry ratio (IAR). Several non-vestibular factors may influence these parameters. Notably, a greater EMG contraction level prior to stimulation leads to an increased amplitude. As aging impacts both vestibular structures and muscle propreties, it is still a matter of debate whether the decrease in cVEMP amplitude observed in normal aging is due to EMG differences prior to stimulation or to the effect of aging on the sacculo-collic reflex pathway. At the clinical level, understanding the effect of aging on the relationship between EMG activity and cVEMP response (amplitude, asymmetry ratio) and the effect of normalization is crucial to improving the categorization of healthy versus pathological responses. OBJECTIVE: To investigate whether normalization modifies cVEMP amplitude and asymmetry ratios differently in younger and older heatlhy adults. METHOD: cVEMP recordings were conducted in 42 normal healthy participants divided in two age groups: younger (n = 29): mean = 22.79 years old SD = 1.66; and older (n = 13): mean = 69.00 years old SD = 3.61. Air-conducted cVEMP were recorded using Eclipse (Interacoustics, Denmark). The stimulus was a 95 dBnHL tone burst (500 Hz) with rise, plateau and fall time of 1 ms. cVEMP were recorded only when EMG levels were between 50μV and 150μV, using the Eclipse (Interacoustic, Denmark) monitoring system. RESULTS: No significant differences were observed for prestimulus EMG levels between younger and older participants (F(1,83) = 1.13, p = 0.291). However, significant differences between groups were observed for raw cVEMP amplitude (F(1,83) = 14.78; p < 0.001) and corrected cVEMP amplitude (F(1,83) = 21.85; p < 0.0001). A significant positive linear relationship between prestimulus EMG contraction level (RMS) and raw cVEMP amplitude was observed in younger participants (r2 = 0.234; p < 0.001), but not in older adults (r2 = –0.0144; p = 0.056). Finally, no significant differences between younger and older participants were observed for raw amplitude asymmetry ratios (F(1,41) = 0.124, p = 0.726) or normalized asymmetry ratios (F(1,41) = 0.726, p = 0.508). CONCLUSION: Our results suggest that when EMG is monitored and activation of the SCM is sufficient, the observed decline in cVEMP amplitude with normal aging does not seem to be caused by EMG differences and is therefore likely due to the known histopathological modifications of the vestibular system that occurs with normal aging.

Comparison of Shoulder Functions Between Workers With and Without Shoulder Impingement Syndrome

The occurrence of shoulder impingement syndrome (SIS) is associated with the frequent handling and lifting of heavy loads and excessive repetitive work above the shoulder level. Thus, assembly workers have a high prevalence of shoulder injuries, including SIS. The purpose of this study was to investigate differences in shoulder ROM, muscle strength, asymmetry ratio, function, productivity, and depression between workers with and without SIS.Sixty-seven assembly line male workers (35 workers with SIS and 32 workers without SIS) participated in this study. The four shoulder ROMs and the five muscle strengths were measured using a Smart KEMA system. The asymmetry ratios were calculated using the asymmetry ratio formula; shoulder functions were measured using the shoulder pain and disability index (SPADI), disabilities of the arm, shoulder, and hand (DASH), and visual analogue scale (VAS); and Endicott work productivity scale (EWPS). Severity of depression was measured using the Beck depression inventory (BDI). Independent t-tests were performed for statistical analysis.The SPADI, DASH, and VAS values of workers with SIS were significantly higher than those of workers without SIS. Also, workers with SIS had significantly smaller shoulder internal rotation and shoulder abduction compared to workers without SIS. In addition, workers with SIS exhibited significantly lower SIR muscle strength than workers without SIS. Workers with SIS had significantly higher asymmetry ratios in shoulder internal rotation, shoulder external rotation, and elbow flexion muscle strength than workers without SIS.The SPADI and DASH scores, which indicate shoulder function, were higher, and the intensity of self-aware pain was higher in workers with SIS. Also, workers with SIS exhibited reduced SIR and SAB ROMs; decreased SIR muscle strength. Particularly, the asymmetry ratios of SIR, SER, EF muscle strength are good comparable factors for workers with and without SIS. In addition, the asymmetry ratios of shoulder muscle strengths could provide an important baseline comparison for the workers with SIS.