Search

Abstract Background Estrogen and progesterone are the primary female sex hormones and have net excitatory and inhibitory effects, respectively, on neuronal function. Fluctuating concentrations across the menstrual cycle has led to several lines of research in relation to neuromuscular function and performance; however evidence from animal and cell culture models has yet to be demonstrated in human motor units coupled with quantification of circulating hormones. Intramuscular electromyography was used to record motor unit potentials and corresponding motor unit potential trains from the vastus lateralis of nine eumenorrheic females during the early follicular, ovulation and mid luteal phases of the menstrual cycle, alongside assessments of neuromuscular performance. Multi-level regression models were applied to explore effects of time and of contraction level. Statistical significance was accepted as p 0.4). Firing rate of low threshold motor units (10% maximum voluntary contraction) was lower during the ovulation and mid luteal phases (β = − 0.82 Hz, p 0.3). Conclusions Assessments of neuromuscular performance did not differ across the menstrual cycle. The suppression of low threshold motor unit firing rate during periods of increased progesterone may suggest a potential inhibitory effect and an alteration of recruitment strategy; however this had no discernible effect on performance. These findings highlight contraction level-dependent modulation of vastus lateralis motor unit function over the eumenorrheic cycle, occurring independently of measures of performance.

Abstract Force output of muscle is partly mediated by the adjustment of motor unit (MU) firing rate (FR). Disparities in MU features in response to fatigue may be influenced by contraction type, as concentric (CON) and eccentric (ECC) contractions demand variable amounts of neural input, which alters the response to fatigue. This study aimed to determine the effects of fatigue following CON and ECC loading on MU features of the vastus lateralis (VL). High‐density surface (HD‐sEMG) and intramuscular (iEMG) electromyography were used to record MU potentials (MUPs) from bilateral VLs of 12 young volunteers (six females) during sustained isometric contractions at 25% and 40% of the maximum voluntary contraction (MVC), before and after completing CON and ECC weighted stepping exercise. Multi‐level mixed effects linear regression models were performed with significance assumed as P 0.1) but neuromuscular junction transmission instability increased in both legs (P

Purpose. This study centers around the Wangzhanghe Country Park located in Jiaozuo City as the research object. Through analysis of the site’s evolution by GPS and its status-quo by GIS, the map of spatial distribution suitability has been illustrated. Design. Based on the major principle of achieving sustainable development of the ecosystem and the derived concept of building a diversified landscape, we have developed the overall scheme of planning and landscape layout of the country park. Specifically, the area of ecological restoration is further divided into the areas of quarry restoration, bare land restoration, slope protection, vegetation, and dam maintenance, and restorative measures are put forward accordingly. Findings. Our research findings indicate that thanks to the vegetation restoration of the side slope, the area of bare land in mountain farmland has been evidently reduced, whereas the severely damaged ash pits and green spots have also been restored. Originality: in the meantime, we have leveraged the flat space at the foot of the mountain to foster a viewing experience and provide recreational activities for citizens, so that they are able to effectively increase their access to outdoor events and improve their sense of engagement and experience in the events, thereby providing a reference for building a green, diverse, and sustainable system of ecological services for the urban country park.

Picea wilsonii is widely used for a forestation and landscaping in China. However, the molecular mechanisms underlying abiotic stress tolerance in this species remain elusive. In this study, we examined the transcriptomic changes induced by drought and salt stress in 8-week-old seedlings of P. wilsonii via RNA-Seq analysis; seedlings grown under normal conditions (without abiotic stress) served as a control. Approximately 36.26 Gb of transcriptome data were obtained from the three treatments. A total of 4171 (2579 up-regulated and 1732 down-regulated) and 3438 (1592 up-regulated and 1706 down-regulated) differentially expressed genes were identified under drought and salt treatments, respectively. Both RNA-Seq and qRT-PCR analyses showed that the expression of PwNAC genes, including PwNAC11, 24, 36, 38, 45, 47, 51 and 52, was greatly induced not only by salt stress but also by drought treatment, suggesting that these genes are involved in both salt and drought stress resistance in P. wilsonii. This is the first report of the transcriptome analysis of P. wilsonii. Our data will serve as a valuable genomic resource for the further characterization of the molecular mechanisms underlying abiotic stress tolerance in P. wilsonii.

We show a detailed study on the dynamics of a neutral delay differential population model with age structure in the prey species. By selecting the mature delay as a bifurcation parameter, we obtain the stability and Hopf bifurcations of the coexistence equilibrium. Moreover, by computing the normal form on the center manifold, we give the formulas determining the stability of periodic solutions and the direction of Hopf bifurcation. Finally, we give some numerical simulations to support and strengthen the theoretical results.

Abstract We analyze the stability of positive equilibrium in a predator-prey model with time delay τ and subsidies. The sufficient conditions of the local Hopf bifurcations at the positive equilibrium are obtained. By center manifold theorem and normal form theory, we analyze the direction of Hopf bifurcations and stability of the bifurcating periodic solution. Using the global Hopf bifurcation theorem, we find that each connected component is unbounded. High-dimensional Bendixson theorem is used to prove that the system has no nonconstant periodic solutions of τ-period, then we obtain the global existence of periodic solutions. Finally, a numerical example is performed to support the theoretical results, and the effect of the food subsidy is discussed. We find that the food subsidy will make the stable interval [0,τ0) $[0,\tau _{0})$ of positive equilibrium larger with τ0 $\tau _{0}$ the first Hopf bifurcation value.

Establishing parity-time (PT) symmetry in non-spatial space is a promising way to simplify the PT-symmetry system structure. In this paper, an implementation of PT symmetry in optical polarization space is reported. By utilizing the polarization multiplexing technology, PT symmetry is formed in overlapping spatial parameter space. The degeneracy of eigenmodes with two distinct PT phases in polarization space is demonstrated. In the PT-symmetric phase, the eigenmodes have real eigenfrequencies that respect PT symmetry, exhibiting broken degeneracy (mode splitting); in the PT-broken phase, the eigenmodes are degenerate with a pair of complex conjugate eigenfrequencies. The sharp-pointed peak filter response in the PT-broken phase due to the strong field localization is characterized, which explains the mode-selection mechanism of PT-symmetry breaking. The polarization-space PT symmetry is applied in a 7-km single-loop optoelectronic oscillator, and a stable single-mode oscillation signal is generated with a phase noise of −138 dBc/Hz at 10 kHz and side-mode suppression ratio of 49 dB. The approach expands the parameter spaces to carry out PT symmetry and could promote the integration of the PT-symmetry photon system.

Antimony selenide is a promising semiconductor with great application potential in the fields of optoelectronic devices. In this work, the vapor transport deposition (VTD) method is employed to prepare Sb2Se3 films on substrates. The influence of deposition temperature, distance between the Sb2Se3 sources and substrate, and the deposition holding time on the film morphology is investigated in detail. The deposited Sb2Se3 thin film is employed to fabricate photodetector with a structure of ITO/SnO2/Sb2Se3/Au, where the spin-coated SnO2 film is used as the buffer layer. The device demonstrates relative high responsivity in the range of 300–1000nm with a maximum value of 312mA W−1 at 750nm.

In this paper, we consider a system of delay differential equations that models the oncolytic virotherapy on solid tumours with the delay of viral infection in the presence of the innate immune response. We conduct qualitative and numerical analysis, and provide possible medical implications for our results. The system has four equilibrium solutions. Fixed point analysis indicates that increasing the burst size and infection rate of the viruses has positive contribution to the therapy. However, increasing the immune killing infection rate, the immune stimulation rate, or the immune killing virus rate may lead the treatment failed. The viral infection time delay induces backward Hopf bifurcations, which means that the therapy may fail before time delay increases passing through a Hopf bifurcation. The parameter analysis also shows how saddle-node and Hopf bifurcations occur as viral burst size and other parameters vary, which yields further insights into the dynamics of the virotherapy.

We propose a novel technique for joint modulation format identification and frequency offset (FO) estimation. The linear frequency modulation signal which is obtained by a direct current signal and Fractional Fourier Transform (FrFT) is superimposed on the data symbols to mark and identify the modulation formats. Simulation results demonstrate our method can identify the DPBPSK, DPQPSK, DP8PSK, DP16QAM, DP32QAM and DP64QAM modulation formats correctly before chromatic dispersion compensation even the optical signal to noise ratio is extremely low. Additionally, due to the excellent time and frequency analysis properties of FrFT, the FO estimation range is greatly extended compared with the traditional Viterbi-Viterbi method.

BackgroundCognitive frailty describes cognitive impairment associated with physical decline. Few studies have explored whether short cognitive screens identify frailty. We examined the diagnostic accuracy of the Chinese versions of the Quick Mild Cognitive Impairment (Qmci-CN) screen and Montreal Cognitive Assessment (MoCA-CN) in identifying cognitive frailty.MethodsNinety-five participants with cognitive symptoms [47 with mild cognitive impairment (MCI), 34 with subjective cognitive disorder, and 14 with dementia] were included from two outpatient rehabilitation clinics. Energy (work intensity) and physical activity levels were recorded. Cognitive frailty was diagnosed by an interdisciplinary team using the IANA/IAGG consensus criteria, stratified on the Clinical Frailty Scale (CFS). Instruments were administered sequentially and randomly by trained assessors, blind to the diagnosis.ResultsThe mean age of the sample was 62.6 ± 10.2 years; median CFS score was 4 ± 1 and 36 (38%) were cognitively frail. The Qmci-CN had similar accuracy in differentiating the non-frail from cognitively frail compared to the MoCA-CN, AUC 0.82 versus 0.74, respectively (p = 0.19). At its optimal cut-off (≤55/100), the Qmci-CN provided a sensitivity of 83% and specificity of 67% versus 91% and 51%, respectively, for the MoCA-CN (≤23/30). Neither was accurate in separating MCI from cognitive frailty but both accurately separated cognitive frailty from dementia.ConclusionEstablished short cognitive screens may be useful in identifying cognitive frailty in Chinese adults with cognitive complaints but not in separating MCI from cognitive frailty. The Qmci-CN had similar accuracy to the MoCA-CN and a shorter administration time in this small and under-powered study, necessitating the need for adequately powered studies in different healthcare settings.

This paper aims to provide bifurcation analysis for a Kuramoto model with time-delay and random coupling strength. A delay differential equation governing the system is obtained on the Ott-Antonsen’s manifold, and the bifurcation analysis is proceeded by using the characteristic equation and the normal form method. The general case where the coupling strength is chosen as a function of delay is investigated. Afterwards, the synchronization of the model with three different distributions of time delay including degenerate distribution, two-point distribution and Gamma distribution, is discussed respectively. Particularly, the coupled system of which the coupling strength and the delays are divided into two groups is studied in detail and the bifurcation results are obtained both theoretically and numerically.

A hysteresis-less inverted perovskite solar cell (PSC) with power conversion efficiency (PCE) of 13.57% was successfully achieved based on the thermal-decomposed NiOx hole contact layer, possessing better electron blocking and hole extraction properties for its suitable work function and high-conduction band edge position. Herein, the transparent and high-crystalline NiOx film is prepared by thermal-decomposing of the solution-derived Ni(OH)2 film in our study, which is then employed as hole transport layer (HTL) of the organic–inorganic hybrid PSCs. Reasonably, the post-annealing treatment, especially for the annealing temperature, could greatly affect the Ni(OH)2 decomposition process and the quality of decomposed NiOx nanoparticles. The vital NiOx HTLs with discrepant morphology, crystallinity and transmission certainly lead to a wide range of device performance. As a result, an annealing process of 400∘C/2h significantly promotes the photovoltaic properties of the NiOx layer and the further device performance.