Tuning the Chern number in quantum anomalous Hall insulators.

A quantum anomalous Hall (QAH) state is a two-dimensional topological insulating state that has a quantized Hall resistance of h/(Ce2) and vanishing longitudinal resistance under zero magnetic field (where h is the Planck constant, e is the elementary charge, and the Chern number C is an integer)1,2. The QAH effect has been realized in magnetic topological insulators3-9 and magic-angle twisted bilayer graphene10,11. However, the QAH effect at zero magnetic field has so far been realized only for C = 1. Here we realize a well quantized QAH effect with tunable Chern number (up to C = 5) in multilayer structures consisting of alternating magnetic and undoped topological insulator layers, fabricated using molecular beam epitaxy. The Chern number of these QAH insulators is determined by the number of undoped topological insulator layers in the multilayer structure. Moreover, we demonstrate that the Chern number of a given multilayer structure can be tuned by varying either the magnetic doping concentration in the magnetic topological insulator layers or the thickness of the interior magnetic topological insulator layer. We develop a theoretical model to explain our experimental observations and establish phase diagrams for QAH insulators with high, tunable Chern number. The realization of such insulators facilitates the application of dissipationless chiral edge currents in energy-efficient electronic devices, and opens up opportunities for developing multi-channel quantum computing and higher-capacity chiral circuit interconnects.

Multifunctional 2-bit coded reconfigurable metasurface based on graphene-vanadium dioxide.

In this paper, a graphene-vanadium dioxide-based reconfigurable metasurface unit structure is proposed. Using the change at a graphene Fermi energy level on the surface of the unit structure to satisfy the 2-bit coding condition, four reflection units with a phase difference of 90 ∘ can be discovered. The modulating impact of the multi-beam reflection wave with 1-bit coding is then confirmed. Then we study the control of a single-beam reflected wave by metasurfaces combined with a convolution theorem in a 2-bit coding mode. Finally, when vanadium dioxide is in an insulating condition, the structure can also be transformed into a terahertz absorber. It is possible to switch between a reflection beam controller and a terahertz multifrequency absorber simply by changing the temperature of the vanadium dioxide layer without retooling a new metasurface. Moreover, compared with the 1-bit coded metasurface, it increases the ability of single-beam regulation, which makes the device more powerful for beam regulation.

Independent and combined associations of handgrip strength and walking speed with cognitive function in older adults: evidence from a national cross-sectional study.

OBJECTIVES: Although there have been studies on the association of handgrip strength or walking speed alone with cognitive abilities, few studies have determined the combined associations of handgrip strength and walking speed with cognitive function. Therefore we aimed to explore the independent and combined associations of handgrip strength and walking speed with cognitive function in Chinese older adults using a nationally representative sample. METHOD: This cross-sectional study included 4,577 adults aged 60 and older. Handgrip strength was measured using a dynamometer and walking speed was assessed using a 2.5-meter walking test. Both handgrip strength and walking speed were organized into low, normal, and high tertiles according to the sample distribution. Cognitive function was measured using the Telephone Interview for Cognitive Status. RESULTS: Handgrip strength and walking speed were significantly associated with cognitive function. Participants with low handgrip strength or low walking speed separately had a higher rate of lower cognitive function (adjusted odds ratio (OR): 1.22 (95% CI: 1.04 - 1.44) for low handgrip strength; 1.54 (95% CI: 1.31 - 1.81) for low walking speed). Those with both low handgrip strength and low walking speed had an additively higher rate of lower cognitive function (adjusted OR: 1.72 (95% CI: 1.32 - 2.24)). CONCLUSION: Having low handgrip strength or low walking speed is associated with a greater likelihood of lower cognitive function and vice versa. The concurrence of having low handgrip strength and low walking speed has an additive effect on cognitive function in older adults.

Separate and combined associations of obesity and handgrip strength with cognitive function in older adults: A national cross-sectional study in China.

This study examined the separate and combined associations of obesity and handgrip strength with cognitive function in older adults. In total 4,839 older adults were included in this cross-sectional study, and their body mass index (BMI) and handgrip strength were measured. Cognitive function was evaluated using the Telephone Interview for Cognitive Status. Three individual categories were created for BMI (normal weight: 18.5≤ BMI < 24.0 kg/m2 overweight: 24.0≤ BMI < 28.0 kg/m2 and obesity: BMI ≥ 28.0 kg/m2 and handgrip strength (low, normal, and high tertiles), and then these categories were pooled together. Logistic regression analyses were used to examine the individual and combined associations of obesity and handgrip strength with cognitive function. Results indicated that overweight adults had a lower rate of lower cognitive function than normal weight adults. There was an inverse association between handgrip strength and cognitive function. Participants with overweight and high handgrip strength had a lower likelihood of lower cognitive function compared to those with normal weight and normal handgrip strength. The findings suggested that overweight or high handgrip strength was associated with lower odds of cognitive decline. Moreover, the concurrence of overweight and high handgrip strength had an additive effect on cognitive function in older adults.

Association of sleep duration with underweight and obesity in older adults: A cross-sectional study of the Chinese longitudinal healthy longevity survey.

OBJECTIVES: Underweight and obesity are two of the main health concerns as they are associated with adverse health outcomes and nutrition disorders. This study determined the association of sleep duration with both underweight and obesity in Chinese older adults. METHODS: This cross-sectional secondary data analysis was conducted using data from the 2018 wave of the Chinese Longitudinal Healthy Longevity Survey. There were 13 917 participants aged 65 and above in the analysis. Body mass index (BMI) was categorized into underweight, normal weight and overweight, and obesity. Self-reported sleep duration was divided into short, normal, and long sleep duration. Logistic regression models were used to examine the association of sleep duration with underweight and obesity. RESULTS: The prevalence of underweight was 16.7% and the prevalence of obesity was 8.0% in Chinese older adults aged 65 and older. Compared to the normal sleep duration group, the short sleep duration group had a higher incidence of underweight (AOR = 1.29, 95% CI: 1.01-1.65), and the long sleep duration group showed a higher incidence of obesity (AOR = 1.57, 95% CI: 1.07-2.30) in older men. A greater incidence of underweight was found in the short sleep duration group (AOR = 1.19, 95% CI: 1.02-1.40) in old-old adults after adjusting for covariates. CONCLUSIONS: Short sleep duration is associated with being underweight and long sleep duration is linked with obesity in older men. Short sleep duration is also a risk factor for the underweight of old-old adults.

A Cooperative Hunting Method for Multi-USV Based on the A* Algorithm in an Environment with Obstacles.

A single unmanned surface combatant (USV) has poor mission execution capability, so the cooperation of multiple unmanned surface ships is widely used. Cooperative hunting is an important aspect of multi USV collaborative research. Therefore, this paper proposed a cooperative hunting method for multi-USV based on the A* algorithm in an environment with obstacles. First, based on the traditional A* algorithm, a path smoothing method based on USV minimum turning radius is proposed. At the same time, the post order traversal recursive algorithm in the binary tree method is used to replace the enumeration algorithm to obtain the optimal path, which improves the efficiency of the A* algorithm. Second, a biomimetic multi USV swarm collaborative hunting method is proposed. Multiple USV clusters simulate the hunting strategy of lions to pre-form on the target's path, so multiple USV clusters do not require manual formation. During the hunting process, the formation of multiple USV groups is adjusted to limit the movement and turning of the target, thereby reducing the range of activity of the target and improving the effectiveness of the algorithm. To verify the effectiveness of the algorithm, two sets of simulation experiments were conducted. The results show that the algorithm has good performance in path planning and target search.

Developing a predictive equation of muscular age to evaluate muscle health in Chinese community-dwelling older women.

Muscle health plays an important role in most common age-related diseases and injuries. To date, a standardized quantitative method to assess muscle health has not yet been developed. Principal component analysis was employed to develop a predictive equation of muscular age based on muscle health variables including skeletal muscle mass of lower limb, grip strength and maximal gait speed. Then validity of muscular age was tested by comparing chronological age to muscular age of the elderly. A predictive equation of muscular age was developed. Muscular age = 0.690 × chronological age - 1.245 × skeletal muscle mass of lower limb + 0.453 × grip strength - 1.291 × maximal walking speed + 40.547. Cross-sectional validity test showed that the predictive equation of muscular age is a valid method to assess muscle health. It is applicable not only to the normal elderly but to the elderly with pre-sarcopenia or sarcopenia.

Evaluating the association between anthropometric parameters and successful aging in older adults.

This study aimed to determine the relationship between successful aging (SA) and anthropometric parameters in older adults. We used body mass index (BMI), waist circumference, hip circumference, and calf circumference to reflect anthropometric parameters. SA was assessed by the following five aspects: self-rated health, self-rated psychological status or mood, cognitive function, activities of daily life, and physical activity. Logistic regression analyses were employed to examine the relationship between anthropometric parameters and SA. Results showed that larger BMI, waist circumference, and calf circumference are related to a higher prevalence of SA in older women; greater waist circumference and calf circumference are associated with a higher rate of SA in old-old adults. These findings suggest that the greater BMI, waist circumference, hip circumference, and calf circumference are associated with a higher rate of SA in older adults, and the associations are influenced to some extent by the sex and age.

Relationship between specific leisure activities and successful aging among older adults.

Background/Objectives: This study was designed to investigate the association between specific leisure activities and successful aging among older adults, using data from the Chinese Longitudinal Healthy Longevity Survey. Methods: A total of 7689 older adults were involved in this study and categorized as successful aging group (n = 3989; 51.8%) or non-successful aging group (n = 3703; 48.2%). Participants were identified as successful aging if they had a score of more than 3 points, or as non-successful aging. The points were based on the following five items and each item was assigned 1 point: self-rated health, self-rated psychological status or mood, cognitive function, activities of daily life, and physical activity. Six activities including gardening work, reading newspapers or books, raising domestic animals or pets, playing cards or mahjong, watching TV or listening to radio, and participating in social activities were collected to reflect leisure activities. Chi-square tests, independent sample t-test, and logistic regression analyses were employed to explore the association between specific leisure activities and successful aging. Results: The prevalence of successful aging was 51.8% among Chinese older adults. A significant positive relationship was found between the frequency of participation in specific leisure activities and successful aging (p < 0.05). Older adults who usually participated in leisure activities had greater odds for successful aging compared to those who never participated in leisure activities (adjusted odds ratio (OR): 1.31 (95% CI: 1.15-1.49) to 1.88 (95% CI: 1.62-2.19)). Older adults participating in one or more leisure activities had greater odds for successful aging compared to those who did not participate in leisure activities (adjusted OR: 1.51 (95% CI: 1.30-1.76) to 4.10 (95% CI: 2.44-6.89)). Conclusions: The findings provide evidence that participating more frequently and in more leisure activities was associated with a greater probability of successful aging among Chinese older adults. Encouraging older people to participate frequently in a larger number of leisure activities may be a key to promote successful aging. Therefore, the frequency and number of participation in leisure activities should be highlighted and targeted for promoting successful aging.

Tactile angle discriminability improvement: contributions of working memory training and continuous attended sensory input.

Perceptual learning is commonly assumed to enhance perception through continuous attended sensory input. However, learning is generalizable to performance in untrained stimuli and tasks. Although previous studies have observed a possible generalization effect across tasks as a result of working memory (WM) training, comparisons of the contributions of WM training and continuous attended sensory input to perceptual learning generalization are still rare. Therefore, we compared which factors contributed most to perceptual generalization and investigated which skills acquired during WM training led to tactile generalization across tasks. Here, a Braille-like dot pattern matching n-back WM task was used as the WM training task, with four workload levels (0, 1, 2, and 3-back levels). A tactile angle discrimination (TAD) task was used as a pre- and posttest to assess improvements in tactile perception. Between tests, four subject groups were randomly assigned to four different workload n-back tasks to consecutively complete three sessions of training. The results showed that tactile n-back WM training could enhance TAD performance, with the 3-back training group having the highest TAD threshold improvement rate. Furthermore, the rate of WM capacity improvement on the 3-back level across training sessions was correlated with the rate of TAD threshold improvement. These findings suggest that continuous attended sensory input and enhanced WM capacity can lead to improvements in TAD ability, and that greater improvements in WM capacity can predict greater improvements in TAD performance.NEW & NOTEWORTHY Perceptual learning is not always specific to the trained task and stimuli. We demonstrate that both continuous attended sensory input and improved WM capacity can be used to enhance tactile angle discrimination (TAD) ability. Moreover, WM capacity improvement is important in generalizing the training effect to the TAD ability. These findings contribute to understanding the mechanism of perceptual learning generalization across tasks.

Pathophysiology and Clinical Management of Autoimmune Encephalitis-Associated Seizures.

Seizures are a very common manifestation of autoimmune encephalitis (AE), ranging from 33% to 100% depending on the antigen, most often accompanied by other clinical features such as behavioral changes, movement disorders, memory deficits, autoimmune disturbances, and altered levels of consciousness. Unusual seizure frequency, resistance to antiepileptic treatment, and often, definitive response to immunotherapy emphasize the importance for neurologists to consider the probable etiology of immune disorders. Studies on pathogenic mechanisms of autoantibodies have improved the understanding of different pathophysiologies and clinical characteristics of different AE groups. In encephalitis with antibodies to neuronal extracellular antigens, autoantibodies play a direct role in disease pathogenesis. They have access to target antigens and can potentially alter the structure and function of antigens but induce relatively little neuronal death. Prompt immunotherapy is usually very effective, and long-term antiepileptic treatment may not be needed. In contrast, in encephalitis with antibodies against intracellular antigens, autoantibodies may not be directly pathogenic but serve as tumor markers. These autoantibodies cannot reach intracellular target antigens and are considered to result from a T-cell-mediated immune response against antigens released by apoptotic tumor cells, which contain nerve tissue or express neuronal proteins. Neuronal loss is frequently described and predominantly induced through cytotoxic T-cell mechanisms. They often exhibit an inadequate response to immunotherapy and require early tumor treatment. Long-term antiepileptic treatment is usually needed. In conclusion, each neural autoantibody can specifically precipitate seizures. Early proper management of these cases may help prevent neurological deterioration and manage the occurrence of seizures. Consequently, confirmation of the presence of neuronal autoantibodies is strongly recommended even in patients with confirmed AE, as they are not only essential in achieving a good outcome but also may provide evidence for underlying neoplasia.

Predictive growth kinetic parameters and modelled probabilities of deoxynivalenol production by Fusarium graminearum on wheat during simulated storing conditions.

AIMS: Mathematical models were employed to predict the growth kinetic parameters of Fusarium graminearum and the accumulation of deoxynivalenol (DON) during wheat storage as a function of different moisture contents (MCs) and temperatures. METHODS AND RESULTS: The colony counting method was used to quantify F. graminearum growth under different environmental conditions, and kinetic and probability models were developed to describe the effect of different MCs and temperatures on fungal growth and DON production during wheat storage. Among the employed secondary models (Arrhenius-Davey, Gibson and Cardinal), the general polynomial best predicted the fungal growth rate under varying temperature and MC during wheat storage. According to the logistic model, DON contamination was correctly predicted in 96.5% of cases. CONCLUSIONS: The maximum growth rate of fungi was 0.4889 ± 0.092 Log CFU g-1  day-1 at 25°C and 30% moisture according to the polynomial model. At below 17°C and ≤15% moisture, no fungal growth was observed. The probability model of toxin production showed no toxin production at less than 15% moisture (aw ≤0.76) and below 15°C. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first application of a probability model of DON production during wheat storage, providing a reference for preventing fungal growth and mycotoxin accumulation by F. graminearum during wheat storage and guaranteeing food product safety.

Programmable bandstop filter based on spoof surface plasmon polaritons.

Spoof surface plasmon polaritons (SSPPs) have been developed rapidly because of the advantages of strong field constraints, low inter-channel cross talk, and low loss. However, the functions of plasmonic devices made of traditional passive SSPPs are completely fixed and cannot reach reconfigurable capability once the devices are fabricated. For the current development status, it is an urgent issue to design a reconfigurable device to control SPP waves dynamically in real time. This paper proposes a dynamic reconfigurable bandstop filter by using the concept of programmable SSPPs. The filter has a significant regulation function in the wideband range from 4 GHz to 22 GHz. The center frequency, number, and bandwidth of the stop band can be reconstructed in real time by programming the bias voltage, and the transmission coefficient (S21) has good transmission performance of more than -3dB. The results show that the experimental processing test is close to the theoretical simulation results, which proves the feasibility of the designed device. The study extends the functional principles of information science and digital logic to the application of physical devices.

Dynamically tunable broadband absorber/reflector based on graphene and VO2 metamaterials.

We propose a difunctional tunable broadband absorber/reflector consisting of a periodic cross-shaped graphene array and a vanadium dioxide (VO2) layer. When VO2 reflects the properties of metal, the proposed dual-function device is used as a reflector; when VO2 reflects the nature of the dielectric, the difunctional device will be used as an absorber. The simulation results indicate that more than 90% absorption bandwidth can be available in the absorber in the frequency range of 56.1-59.0 THz, up to 100%. Moreover, over 80% absorption can be achieved over the frequency range of 88.5 to 90.2 THz. In addition, the bandwidth and absorption of the metamaterial absorber can be dynamically changed because of the Fermi energy level in graphene and the temperature tunability of VO2. The proposed device can be applied to manufacturing infrared spectrophotometers, on-dispersive infrared photometers, and Fourier transform infrared spectrometers. Therefore, it has potential application in the field of environmental monitoring.

A Hybrid Multi-Target Path Planning Algorithm for Unmanned Cruise Ship in an Unknown Obstacle Environment.

To solve the problem of traversal multi-target path planning for an unmanned cruise ship in an unknown obstacle environment of lakes, this study proposed a hybrid multi-target path planning algorithm. The proposed algorithm can be divided into two parts. First, the multi-target path planning problem was transformed into a traveling salesman problem, and an improved Grey Wolf Optimization (GWO) algorithm was used to calculate the multi-target cruise sequence. The improved GWO algorithm optimized the convergence factor by introducing the Beta function, which can improve the convergence speed of the traditional GWO algorithm. Second, based on the planned target sequence, an improved D* Lite algorithm was used to implement the path planning between every two target points in an unknown obstacle environment. The heuristic function in the D* Lite algorithm was improved to reduce the number of expanded nodes, so the search speed was improved, and the planning path was smoothed. The proposed algorithm was verified by experiments and compared with the other four algorithms in both ordinary and complex environments. The experimental results demonstrated the strong applicability and high effectiveness of the proposed method.

Association of body mass index and waist circumference with falls in Chinese older adults.

This study explored the association of obesity as determined by body mass index (BMI) and waist circumference (WC) with falls in Chinese older adults. It was a cross-sectional design and used data from the Chinese Longitudinal Healthy Longevity Survey. The outcome variable was experienced falls, and the exposure variables were BMI and WC which represent general obesity and central obesity respectively. For older women, a linear correlation was found between falls and BMI. For participants aged 90 years and older, there was a linear correlation between falls and BMI. Participants with WC in the fourth quartile had a higher risk of falls than those in the first quartile. The findings suggest that the general obesity indicator (BMI), rather than the central obesity index (WC), was positively associated with falls in older women. The risk of falls increased with the increase of BMI or WC in the oldest-old Chinese population.

Do Arch Height and Arch Stiffness Relate to Physical Performance in Adult Men?

Foot arch plays an important role in bearing body weight, absorbing ground reaction forces and maintaining balance, and its structure and function are bound to have a profound effect on physical activities and sports. Arch height and arch stiffness are 2 factors that represent the structure and function of the arch. Therefore, the purpose of this study was to explore the associations of arch height and arch stiffness with physical performance. A total of 56 men (aged 49.00 ± 7.95 years, mean body mass index [BMI] 26.80 ± 3.75 kg/m2) participated in this study. A 3-dimensional laser scanner was employed to obtain foot structure information of each participant, from which the arch height index (AHI) and arch stiffness index (ASI) were computed. Physical performance measures including agility, power, and proprioception were tested in a random order. The results indicated that the stepping forward and backward and vertical jump that represent agility and force respectively were negatively and significantly associated with AHI (r = -0.27, p = .045; r = -0.35, p = .009). When adjusted for age and BMI, only height of vertical jump was found to be correlated significantly with AHI (r = -0.29, p = .040); while no significant relationships were observed between physical performance measures and ASI. Multivariate linear regression analysis showed that AHI, age, and BMI can effectively predict the height of vertical jump. This study demonstrates that there is a negative correlation between arch height and muscle power of lower limbs in adult men.

The emerging role of circular RNAs in common solid malignant tumors in children.

Malignant tumors are one of the fatal diseases that threaten children's physical and mental health and affect their development. Research has shown that the occurrence and development of malignant tumors are associated with the abnormal expression and regulation of genes. Circular RNAs (circRNAs) are noncoding RNAs that have a closed circular structure, with a relatively stable expression, and do not undergo exonuclease-mediated degradation readily. Recent studies have shown that circRNA plays an important role in the occurrence, metastasis, and invasion of solid malignant tumors (SMTs) in children. Thus, circRNA is being considered as a breakthrough in the treatment of SMTs in children. In this review, we describe the functions and mechanisms of circRNAs involved in SMTs in children oncogenesis, and summarize the roles of circRNAs in regulating cell proliferation, cell apoptotic death, the cell cycle, cell migrative and invasive ability, epithelial-mesenchymal transition (EMT), cancer stem cells and drug resistance in SMTs in children. In addition, we also discuss the role of circRNAs in the early diagnosis, pathological grading, targeted therapy, and prognosis evaluation of common SMTs in children. CircRNAs are likely to provide a novel direction in therapy in SMTs of children.

Phonon Helicity Induced by Electronic Berry Curvature in Dirac Materials.

In two-dimensional insulators with time-reversal (TR) symmetry, a nonzero local Berry curvature of low-energy massive Dirac fermions can give rise to nontrivial spin and charge responses, even though the integral of the Berry curvature over all occupied states is zero. In this Letter, we present a new effect induced by the electronic Berry curvature. By studying electron-phonon interactions in BaMnSb_{2}, a prototype two-dimensional Dirac material possessing two TR-related massive Dirac cones, we find that the nonzero local Berry curvature of electrons can induce a phonon angular momentum. The direction of this phonon angular momentum is locked to the phonon propagation direction, and thus we refer to it as "phonon helicity" in a way that is reminiscent of electron helicity in spin-orbit-coupled electronic systems. We discuss possible experimental probes of such phonon helicity.

Downregulation of hyperpolarization-activated cyclic nucleotide-gated channels (HCN) in the hippocampus of patients with medial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS).

Changes in the expression of HCN ion channels leading to changes in Ih function and neuronal excitability are considered to be possible mechanisms involved in epileptogenesis in kinds of human epilepsy. In previous animal studies of febrile seizures and temporal lobe epilepsy, changes in the expression of HCN1 and HCN2 channels at different time points and in different parts of the brain were not consistent, suggesting that transcriptional disorders involving HCNs play a crucial role in the epileptogenic process. Therefore, we aimed to assess the transcriptional regulation of HCN channels in Medial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) patients. This study included eight nonhippocampal sclerosis patients and 40 MTLE-HS patients. The mRNA expression of HCN channels was evaluated by qRT-PCR, while the protein expression was quantitatively analyzed by Western blotting. The subcellular localization of HCN channels in the hippocampus was explored by immunofluorescence. We demonstrated that the mRNA and protein expression of HCN1 and HCN2 are downregulated in controls compared to that in MTLE-HS patients. In the hippocampal CA1/CA4 subregion and GCL, in addition to a large decrease in neurons, the expression of HCN1 and HCN2 on neuronal cell membranes was also downregulated in MTLE-HS patients. These findings suggest that the expression of HCN channels are downregulated in MTLE-HS, which indicates that the decline in HCN channels in the hippocampus during chronic epilepsy in MTLE-HS patients leads to the downregulation of Ih current density and function, thereby reducing the inhibitory effect and increasing neuronal excitability and eventually causing disturbances in the electrical activity of neurons.