Clinical characteristics and lateralization of the horizontal semicircular canal light cupula.

Introduction: Positional vertigo and nystagmus are the main symptoms and signs of dizziness, respectively. Despite the clinical utility of the supine roll test (SRT) and null point (NP) in diagnosing light cupula, a type of positional vertigo, there exists a notable gap in the literature concerning the comprehensive evaluation of lateralization values based on various nystagmus characteristics and the intensity of direction-changing positional nystagmus (DCPN) in the SRT, particularly in comparison to the NP. Additionally, limited data on abnormal canal paresis (CP) in light cupula patients underscores the need for further research with a larger patient population to elucidate this mechanism. This study aims to investigate the characteristics of positional nystagmus and lateralization of the horizontal semicircular canal (HSCC) light cupula, which is a type of positional vertigo and nystagmus that is poorly understood. Methods: Eighty-five patients (17 males, 68 females; mean age, 60.9 years) with light cupula were reviewed. We summarized the characteristics of spontaneous nystagmus and positional nystagmus, including supine positioning nystagmus, bow nystagmus, and lean nystagmus. Then, the side of the NP was identified as the affected side, and the values of the fast phase direction of the spontaneous nystagmus, supine positioning nystagmus, bow nystagmus, and lean nystagmus, as well as the intensity of the DCPN in the SRT, were used to diagnose the affected sides. Caloric testing was also performed for some patients. Results: Light cupula was observed in 5.7% of the patients with positional nystagmus. The frequencies of supine positioning nystagmus (88.2%), bow nystagmus (90.6%), and lean nystagmus (83.5%) were higher than spontaneous nystagmus (61.2%) (p < 0.001). The second NP (NP2) (92.9%) and third NP (NP3) (83.5%) were readily detected, affecting the left and right sides in 38 and 47 patients, respectively. Lateralization through the fast phase directions of bow nystagmus and lean nystagmus did not significantly differ from that of NP (all p > 0.05). However, the accuracy rate of lateralization through the sides with more vigorous DCPN in the SRT was 63.5%, significantly lower than through NP (p < 0.001). Particularly in patients with supine positioning nystagmus (n = 75), the rate was only 58.7% (p < 0.001). However, the rate was 100% in patients without supine positioning nystagmus (n = 10). Among the 70 patients who underwent caloric testing, 37 had abnormal CP, and the sides of the reduced caloric reaction were ipsilateral to the affected sides of the light cupula in 83.8% of the patients. Conclusion: Besides utilizing the NP to determine the affected side, the fast phase direction of the bow nystagmus or lean nystagmus can also aid in identification. However, a simple comparison of the intensity of DCPN in SRT cannot provide accurate lateralization, especially in patients with supine positioning nystagmus. There is a high incidence of CP on the affected side of the light cupula.

Natural strategies for creating non-equilibrium morphology with self-repairing capability towards rapid growth of excellent YBa2Cu3O7-δ crystals.

Self-repair, as a natural phenomenon, has been vastly observed and investigated in a variety of fields. With such an ability, living species self-heal their wounds to restore physiological functions while non-biological materials return to their original states, for example, thin surface layer growth occurs in the regeneration of incomplete KH2PO4 crystals. Here, two seeding strategies are developed for creating incomplete crystallographic shapes (i.e. right-angled concave corners) of YBa2Cu3O7-δ (YBCO) superconducting crystals with self-repairing capability in top-seeded melt growth. One involves in situ self-assembly seeding, by which the ability to self-repair promotes YBCO growth; the other is vertically connected seeding, by which self-repair triggers YBCO nucleation. Consequently, rapid surface crystallization originated at concave corners and swiftly generated initial growth morphology approaching equilibrium. Furthermore, these rapid-growth regions including the concave crystal or seed innately functioned as sizable effective seeding regions, enabling the enlargement of the c-oriented growth sector and the enhancement of properties for YBCO crystals. This work demonstrates experimentally that biaxial-in-plane-aligned crystals and precisely perpendicular-arranged seeds are important self-repairing activators for the rapid growth of YBCO crystals. This nature-inspired self-repairing work offers insights into the design of seeding architecture with non-equilibrium morphology for inducing sizable high-performance crystals in the YBCO family and other functional materials.

Objective findings in patients with multi-canal benign paroxysmal positional vertigo.

OBJECTIVE: The study aimed to investigate the clinical characteristics of patients with multi-canal benign paroxysmal positional vertigo (MC-BPPV). METHODS: We performed a retrospective analysis of 927 patients with BPPV who were admitted to our hospital between January 1, 2016 and December 31, 2019. The clinical data of all patients were collected. The Dix-Hallpike, straight head-hanging, and supine Roll tests were performed in all patients. The nystagmus was recorded using videonystagmography. The clinical characteristics of patients with MC-BPPV and single canal BPPV (SC-BPPV) was analyzed and compared. RESULTS: Among 927 patients included, 49 (5.29%) patients had MC-BPPV, 878 (94.71%) patients had SC-BPPV. There were significant differences in the male to female ratio (1:3.90 vs 1:1.81, P < .05), mean age (62.47±12.51 vs 59.04±13.72, P < .05), as well as the ratio of cupulolithiasis to canalithiasis (1:1.45 vs 1:4.78, P < .01) between patients with MC-BPPV and SC-BPPV. The frequency of involvement of PC, HC, and AC were involved for 66 (67.35%), 23 (23.47%), and 9 (9.18%) times, respectively, in patients with MC-BPPV, which were involved in 581 (66.17%), 281 (32.0%), and 16 (1.82%) patients, respectively, in patients with SC-BPPV. No significant difference was found in the frequency of involvement of PC and HC between patients with MC-BPPV and SC-BPPV, while there was significant difference in the frequency of AC involvement between 2 groups (P < .01). Ipsilateral PC-HC-BPPV (n = 18) and bilateral PC-BPPV (n=19) were the most common among patients with MC-BPPV. Twenty-six (53.06%) patients had ipsilateral MC-BPPV, 23 (46.94%) had bilateral MC-BPPV. Of the 26 patients with ipsilateral MC-BPPV, 7 patients combined with unilateral peripheral vestibular disorder. CONCLUSION: Patients with MC-BPPV had a significantly older mean age at disease onset and a higher proportion of females compared with patients with SC-BPPV. Cupulolithiasis was more common in MC-BPPV. AC involvement was also much more common in MC-BPPV than in SC-BPPV.

Humble Leadership and Employee Resilience: Exploring the Mediating Mechanism of Work-Related Promotion Focus and Perceived Insider Identity.

Although the topic of employee resilience has recently received increased attention, existing research has largely failed to explore its situational triggers. Drawing on social information processing theory, the current study integrates the literature of humility and resilience to theorize the underlying mechanism through which humble leadership facilitates employee resilience. This research proposes a potential heterogeneous effect that humble leadership catalyzes employee resilience through multiple pathways. Field (N = 434) and experimental studies (N = 104) conducted in Mainland China support hypotheses that humble leadership enhances employee resilience through simultaneous increases in work-related promotion focus and perceived insider identity. Research implications are discussed, and directions for future research are offered.

Microfluidic assemblies designed for assessment of drug effects on deformability of human erythrocytes.

Extreme deformability of human erythrocytes is a prerequisite for their ability to squeeze through narrow capillaries of the blood microcirculation system. Various drugs can modify this deformability and consequently provoke circulation problems. We demonstrate that microfluidic assemblies are very convenient platforms for in vitro study of the associated processes. Two types of microfluidic channels were designed to quantitatively investigate modifications of erythrocyte deformability induced by hydrogen peroxide, ethanol and pentoxifylline based on transit velocity measurements. With a high sensitivity our microfluidic assemblies show that hydrogen peroxide decreases erythrocyte deformability in a dose-dependent manner. Then, results on ethanol resolve a biphasic nature of this reactant on the deformability of single erythrocyte cells. Results on pentoxifylline provide evidence that, similar to ethanol, also this medical drug has a double-sided effect on the erythrocyte deformability, i.e. increasing the deformability at low concentrations, while decreasing it at higher ones. Taken together, our microfluidic designs propose a potent measurement method for the erythrocyte deformability, as well as providing a perspective to evaluate effects of drugs on it.

Tunable dual-band terahertz metamaterial bandpass filters.

We report metamaterial terahertz (THz) bandpass filters with tunable dual-band selectivity. The shift in the center frequency of the device is achieved by actively modifying the effective length of the resonators. This was realized by introducing vanadium dioxide (VO2) bridges interconnecting specific regions of each resonator. Raising the temperature across the phase transition shifted the resonance frequency by ~32% due to changes in the electrical conductivity of the VO2. Measured THz transmission response of the proposed dual-band filter was in good correspondence with simulations.

Terahertz bandpass filters using double-stacked metamaterial layers.

Bandpass filters are reported based on double-stacked metamaterial layers separated by an air gap for operation at terahertz frequencies. Several stacking configurations were investigated designed for a ~0.5 THz center frequency. The filters exhibited improved spectral transmission properties when compared with conventional ones based on single metamaterial layers. 3 dB bandwidth of ~78 GHz and sidelobe suppression ratio >16 dB were determined when symmetric or asymmetric double layers were stacked. We demonstrate that superior frequency selectivity can be achieved when metamaterial layers with different unit cells are used. Good agreement was found between measured and simulated transmission response.