Yao-Ming Chang

Atherosclerosis and aortic aneurysms are prevalent aortic disorders. Significantly, atherosclerosis frequently impacts the common carotid artery (CA), wher

Introduction: Multitasking during flights leads to a high mental workload, which is detrimental for maintaining task performance. Electroencephalography (EEG) power spectral analysis based on frequency‐band oscillations and microstate analysis based on global brain network activation can be used to evaluate mental workload. This study explored the effects of a high mental workload during simulated flight multitasking on EEG frequency‐band power and microstate parameters.Methods: Thirty‐six participants performed multitasking with low and high mental workloads after 4 consecutive days of training. Two levels of mental workload were set by varying the number of subtasks. EEG signals were acquired during the task. Power spectral and microstate analyses were performed on the EEG. The indices of four frequency bands (delta, theta, alpha, and beta) and four microstate classes (A–D) were calculated, changes in the frequency‐band power and microstate parameters under different mental workloads were compared, and the relationships between the two types of EEG indices were analyzed.Results: The theta‐, alpha‐, and beta‐band powers were higher under the high than under the low mental workload condition. Compared with the low mental workload condition, the high mental workload condition had a lower global explained variance and time parameters of microstate B but higher time parameters of microstate D. Less frequent transitions between microstates A and B and more frequent transitions between microstates C and D were observed during high mental workload conditions. The time parameters of microstate B were positively correlated with the delta‐, theta‐, and beta‐band powers, whereas the duration of microstate C was negatively correlated with the beta‐band power.Conclusion: EEG frequency‐band power and microstate parameters can be used to detect a high mental workload. Power spectral analyses based on frequency‐band oscillations and microstate analyses based on global brain network activation were not completely isolated during multitasking.

Free radicals and oxidative stress play an important role in the pathogenesis of noise-induced hearing loss (NIHL). Some ginseng monomers showed certain therapeutic effects in NIHL by scavenging free radicals. Therefore, we hypothesized that ginsenoside Rd (GSRd) may exert neuroprotective effects after noise-induced auditory system damage through a mechanism involving the SIRT1/PGC-1α signaling pathway. Forty-eight guinea pigs were randomly divided into four equal groups (normal control group, noise group, experimental group that received GSRd dissolved in glycerin through an intraperitoneal injection at a dose of 30 mg/kg body weight from 5 days before noise exposure until the end of the noise exposure period, and experimental control group). Hearing levels were examined by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Hematoxylin–eosin and Nissl staining were used to examine neuron morphology. RT-qPCR and western blotting analysis were used to examine SIRT1/PGC-1α signaling and apoptosis-related genes, including Bax and Bcl-2, in the auditory cortex. Bax and Bcl-2 expression was assessed via immunohistochemistry analysis. Superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined using a commercial testing kit. Noise exposure was found to up-regulate ABR threshold and down-regulate DPOAE amplitudes, with prominent morphologic changes and apoptosis of the auditory cortex neurons (p < 0.01). GSRd treatment restored hearing loss and remarkably alleviated morphological changes or apoptosis (p < 0.01), concomitantly increasing Bcl-2 expression and decreasing Bax expression (p < 0.05). Moreover, GSRd increased SOD and GSH-Px levels and decreased MDA levels, which alleviated oxidative stress damage and activated SIRT1/PGC-1α signaling pathway. Taken together, our findings suggest that GSRd ameliorates auditory cortex injury associated with military aviation NIHL by activating the SIRT1/PGC-1α signaling pathway, which can be an attractive pharmacological target for the development of novel drugs for NIHL treatment.

Purpose: To assess the incidence rate of myopia, refractive change, and the effects of influencing factors on a group of highly selected senior high school students in an Aviation Cadet prerecruitment class in China. Methods: A total of 800 nonmyopic, male, Grade 9 students aged 14- to 16-years old with cycloplegic refraction of −0.25 or greater diopters (D) to 1.75 D or less in both eyes were enrolled in May 2016. During their senior high school studies, students had one 20-minute physical training period a day, and they were encouraged to participate in outdoor activities during class recess without any time limits. The first follow-up was 8 months after enrollment when they were in Grade 10, and the second follow-up was 1 year after the first follow-up when they were in Grade 11. Comprehensive ocular examinations and a detailed questionnaire, which included questions about outdoor activity time, parental myopia, and near work, were completed at each follow-up. Results: The average spherical equivalent refraction (SER) of the right eyes was 0.39 ± 0.44 D at baseline, 0.16 ± 0.41 D at the first follow-up, and −0.10 ± 0.38 D at the second follow-up. The cumulative refractive change was −0.50 D (95% confidence interval [CI], −0.53 to −0.47). The cumulative incidence rate of myopia was 15.5% (124/800). Incident myopia was significantly associated with outdoor activity for more than 1 versus less than 0.5 hr/d (odds ratio [OR] = 0.272, 95% CI, 0.132–0.560), baseline refraction (OR = 0.079, 95% CI, 0.041–0.153), maternal myopia (OR = 2.251, 95% CI, 1.160–4.368), longer class time (OR =3.215, 95% CI, 1.088–9.499), frequent, continuous, and long time reading/writing (OR = 1.620, 95% CI, 1.022–2.570), and shorter reading/writing distance (OR = 1.828, 95% CI, 1.065–3.140). In multiple linear regression model, having outdoor activity for more than 1 hr/d was protective from cumulative SER decrease. A higher baseline refraction together with longer reading/writing time, frequent, continuous, and longtime reading/writing, and shorter reading/writing distance were risk factors for SER decrease. Conclusions: In this cohort of highly selected, nonmyopic students, longer outdoor activity time was a protective factor for both incident myopia and refractive change of myopic shift. The risk factors for incident myopia included lower hyperopic baseline refraction, more near work, and maternal myopia. The risk factors for refractive change of myopic shift included more hyperopic baseline refraction and more near work.

Lysosomal exocytosis and fusion to cellular membrane is critical in the oxidative stress formation of endothelium under apoptotic stimulus. We investigated the role therein of it in hyperglycaemia-induced endothelial dysfunction. The lysosome-membrane fusion was shown by the expression of lamp1, the lysosomal membrane marker, on cellular membrane and the transportation of lysosomal symbolic enzymes into cultural medium. We also examined the ceramide production, lipid rafts (LRs) clustering, colocalization of gp91^phox, a NADPH oxidase subunit (NOX) to LRs clusters, superoxide (O₂^.-) formation and nitric oxide (NO) content in human umbilical vein endothelial cells (HUVEC) and the endothelium-dependent NO-mediated vasodilation in isolated rat aorta. As compared to normal glucose (5.6 mmol/l, Ctrl) incubation, high glucose (22 mmol/l, HG) exposure facilitated the lysosome-membrane fusion in HUVEC shown by significantly increased quantity of lamp1 protein on cellular membrane and enhanced activity of lysosomal symbolized enzymes in cultural medium. HG incubation also elicited ceramide generation, LRs clustering and gp91^phox colocalization to LRs clusters which were proved to mediate the HG induced O₂^.- formation and NO depletion in HUVEC. Functionally, the endothelium-dependent NO-mediated vasodilation in aorta was blunted substantially after HG incubation. Moreover, the HG-induced effect including ceramide production, LRs clustering, gp91^phox colocalization to LRs clusters, O₂^.- formation and endothelial dysfunction could be blocked significantly by the inhibition of lysosome-membrane fusion. We propose that hyperglycaemia-induced endothelial impairment is closely related to the lysosome-membrane fusion and the following LRs clustering, LRs-NOX platforms formation and O₂^.- production.

The large conductance Ca²⁺-activated K⁺ (BK_Ca) channels are highly expressed in vascular smooth muscle cells (VSMCs) and play an essential role in the regulation of various physiological functions. Besides its electrophysiological function in vascular relaxation, BK_Ca has also been reported to be implicated in nitric oxide (NO)-induced apoptosis of VSMCs. However, the molecular mechanism is not clear and has not been determined on cloned channels. The present study was designed to clarify whether activation of cloned BK_Ca channel was involved in NO-induced apoptosis in human embryonic kidney 293 (HEK293) cell. The cDNA encoding the α-subunit of BK_Ca channel, hSloα, was transiently transfected into HEK293 cells. The apoptotic death in HEK-hSloα cells was detected using immunocytochemistry, analysis of fragmented DNA by agarose gel electrophoresis, MTT test, and flow cytometry assays. Whole-cell and single-channel characteristics of HEK-hSloα cells exhibited functional features similar to native BK_Ca channel in VSMCs. Exposuring of HEK- hSloα cells to S-nitroso-N-acetyl-penicillamine increased the hSloα channel activities of whole-cell and single-channel, and then increased percentage of cells undergoing apoptosis. However, blocking hSloα channels with 1 mM tetraethylammonia or 100 nM iberiotoxin significantly decreased the NO-induced apoptosis, whereas 30 μM NS1619, the specific agonist of BK_Ca, independently increased hSloα currents and induced apoptosis. These results indicated that activation of cloned BK_Ca channel was involved in NO-induced apoptosis of HEK293 cells.

The purpose of this study was to observe heart rate and respiration responses to real traffic pattern flight. Nine experienced and nine less-experienced military pilots on active flying status participated in four uninterrupted traffic patterns flight missions with F-7 jet trainer. The heart rates and respiration waves were continuously recorded using a small recording device strapped around the chest. As compared with baseline values, significant increases in heart rates of the two groups (for experienced pilots group, F (11, 88) = 4.636, p = 0.000; for less-experienced, F (11, 88) = 4.437, p = 0.000) and mean respiration rates of less-experienced group (F (11, 88) = 4.488, p = 0.000) were obtained during the phases of take-off, final approach and landing. Heart rates of less-experienced pilots were significant higher than those of experienced pilots during the take-off phase (p < 0.05). There were no significant differences in respiration rates between the two groups at each phase of the whole flight. The results show that take-off, final approach and landing are the most mental workload phases in-flight, and less-experienced pilots show more mental workload than experienced pilots in take-off phase in-flight.

Since biological functions of the elements are generally different, depending on their chemical forms, chemical speciation analysis is really important in metallomics research. Thus, multielement analysis and chemical speciation of the elements in serum were carried out in the present work. A hyphenated technique was developed for high-throughput speciation analysis of the copper, iron and zinc in serum by molecular biology technology and flame atomic absorption spectrophotometry (AAS). Here, Cu, Fe and Zn in serum were classifyied as the forms of combination and non-combination. The serum protein was precipitated by 60% concentration of ethanol under hypothermy. The forms of combination of Cu, Fe and Zn in serum which combined with proteins were in precipitations, and the forms of non-combination of Cu, Fe and Zn in serum, which were free ions, were in supernatant. The total amount of Cu, Fe and Zn in serum and the amount of the forms of non-combination of Cu, Fe and Zn were analyzed by AAS. The amount of the forms of combination of Cu, Fe and Zn was obtained by calculation. The detection limit of Cu in serum by the method is around and 9.84 x 10(-3) microg x mL(-1). For Fe and Zn, the detection limit is about 2.76 x 10(-2) microg x mL(-1) and 1.06 x 10(-3) microg x mL(-1), respectively. The percentage recovery of trace elements Cu, Fe and Zn by the proposed procedure is in the range 95.0%-101.0%, 95.0%-102.0% and 95.0%-103.0%, respectively. The relative standard deviation (RSD) of trace elements Cu, Fe and Zn in the serum is in the range 1.88%-2.26%, 0.56%-1.59% and 0.34%-1.36%, respectively. Speciation of trace elements Cu, Fe and Zn in the serum of SD rat were analyzed by the method.