Precise Measurement of the Stoichiometry of the Adaptive Bacterial Flagellar Switch.

The cytoplasmic ring (C-ring) of the bacterial flagellar motor controls the motor rotation direction, thereby controlling bacterial run-and-tumble behavior. The C-ring has been shown to undergo adaptive remodeling in response to changes in motor directional bias. However, the stoichiometry and arrangement of the C-ring is still unclear due to contradiction between the results from fluorescence studies and cryo-electron microscopy (cryo-EM) structural analysis. Here, by using the copy number of FliG molecules (34) in the C-ring as a reference, we precisely measured the copy numbers of FliM molecules in motors rotating exclusively counterclockwise (CCW) and clockwise (CW). We surprisingly found that there are on average 45 and 58 FliM molecules in CW and CCW rotating motors, respectively, which are much higher than previous estimates. Our results suggested a new mechanism of C-ring adaptation, that is, extra FliM molecules could be bound to the primary C-ring with probability depending on the motor rotational direction. We further confirmed that all of the FliM molecules in the C-ring function in chemotaxis signaling transduction because all of them could be bound by the chemotactic response regulator CheY-P. Our measurements provided new insights into the structure and arrangement of the flagellar switch. IMPORTANCE The bacterial flagellar switch can undergo adaptive remodeling in response to changes in motor rotation direction, thereby shifting its operating point to match the output of the chemotaxis signaling pathway. However, it remains unclear how the flagellar switch accomplishes this adaptive remodeling. Here, via precise fluorescence studies, we measured the absolute copy numbers of the critical component in the switch for motors rotating counterclockwise and clockwise, obtaining much larger numbers than previous relative estimates. Our results suggested a new mechanism of adaptive remodeling of the flagellar switch and provided new insights for updating the conformation spread model of the switch.

SOKS: Automatic Searching of the Optimal Kernel Shapes for Stripe-Wise Network Pruning.

In spite of the remarkable performance, deep convolutional neural networks (CNNs) are typically over-parameterized and computationally expensive. Network pruning has become a popular approach to reducing the storage and calculations of CNN models, which commonly prunes filters in a structured way or discards single weights without structural constraints. However, the redundancy in convolution kernels and the influence of kernel shapes on the performance of CNN models have attracted little attention. In this article, we develop a framework, termed searching of the optimal kernel shape (SOKS), to automatically search for the optimal kernel shapes and perform stripe-wise pruning (SWP). To be specific, we introduce coefficient matrices regularized by a variety of regularization terms to locate important kernel positions. The optimal kernel shapes not only provide appropriate receptive fields for each convolution layer, but also remove redundant parameters in convolution kernels. SWP is also achieved by utilizing these irregular kernels and actual inference speedups on the graphics processing unit (GPU) are obtained. Comprehensive experimental results demonstrate that SOKS searches high-efficiency kernel shapes and achieves superior performance in terms of both compression ratio and inference latency. Embedding the searched kernels into VGG-16 increases the accuracy from 93.53% to 94.26% on CIFAR-10, while pruning 59.27% model parameters and reducing 27.07% inference latency.

An Image Encryption Algorithm Based on Discrete-Time Alternating Quantum Walk and Advanced Encryption Standard.

This paper proposes an image encryption scheme based on a discrete-time alternating quantum walk (AQW) and the advanced encryption standard (AES). We use quantum properties to improve the AES algorithm, which uses a keystream generator related to AQW parameters to generate a probability distribution matrix. Some singular values of the matrix are extracted as the key to the AES algorithm. The Rcon of the AES algorithm is replaced with the elements of the probability distribution matrix. Then, the ascending order of the size of the clone probability distribution matrix scrambles the mapping rules of the S-box and ShiftRow transformations in the AES algorithm. The algorithm uses a probability distribution matrix and plaintext XOR operation to complete the preprocessing and uses the modified AES algorithm to complete the encryption process. The technology is based on simulation verification, including pixel correlation, histograms, differential attacks, noise attacks, information entropy, key sensitivity, and space. The results demonstrate a remarkable encryption effect. Compared with other improved AES algorithms, this algorithm has the advantages of the original AES algorithm and improves the ability to resist correlation attacks.

Effect of climate and ecological restoration on vegetation changes in the "Three-River Headwaters" region based on remote sensing technology.

Surface temperature and precipitation are factors effecting vegetation growth. Vegetation coverage change is one of the important factors influencing global and regional climate change. Dynamic monitoring of vegetation change can reflect the trend of climate change to a certain extent. Three-River Headwaters are located in the hinterland of the Qinghai-Tibet Plateau. It has the characteristics of "high, cold, and dry" (higher altitude, cold and dry weather) and its ecosystem is fragile. In recent years, with the global climate change, a series of eco-environmental problems such as river flow cutoff, permafrost degradation, and vegetation destruction has occurred in the headwaters area, which are closely related to climate and vegetation changes. At the same time, in order to solve the problem of ecological environment degradation in the region, various ecological restoration policies have implemented. Several uncertainties in the relationship between vegetation and climate change in the Three-River Headwaters region. This study aims to find out the uncertainties. In this study, the spatial distribution of vegetation coverage was calculated by using NDVI (normalized difference vegetation index) from the first-level product of MODIS (moderate resolution imaging spectroradiometer) remote sensing data. Combining policy factors, the relationship between rainfall, surface temperature, and vegetation growth status were analyzed. The results show that during the study period (1948-2019), the temperature rose significantly and the rainfall increased especially after the implementation of ecological restoration policy (after 2000). Vegetation coverage increased year-by-year (2000-2015). The rainfall effect on surface temperature and vegetation growth, when the summer rainfall increased, the temperature decreased, leads to vegetation coverage decreased (for example, 2001, 2003, 2008 and 2011); the dependence of vegetation on rainfall has obvious lag in Three-River Headwaters in summer. In the years with suitable rainfall and higher temperature in summer, the vegetation grows better and the vegetation coverage increases. This is mainly because the Three-River Headwaters is located in the alpine zone, and vegetation growth is more dependent on temperature. The implementation of ecological restoration policy promotes vegetation coverage. Studying the impact of climate and policy factors on vegetation cover is of great scientific significance and practical value for understanding the ecological restoration mechanism in high cold and arid regions.

Do Health Expenditures Converge Among ASEAN Countries?

This paper aims to determine the existence of convergence in health expenditures among Association for South East Asian Nations (ASEAN) countries. Based on the SPSM procedure and panel KSS unit root test results, the public health expenditures (PUHE) in Indonesia, Lao PDR, Cambodia, the Philippines, and Myanmar are converging, while that of Brunei Darussalam, Malaysia, Vietnam, Singapore, and Thailand are diverging. In addition, the sequences of private health expenditures (PRHE) in ASEAN member states are stationary, which implies convergence. This finding is in accordance with Wagner's law, that is, as nations develop, they are forced to expand public expenditure. Specifically, countries with low levels of PUHE tend to catch up with the high health spending countries. This research has policy implications with regard to the convergence of health expenditure across countries. The government in low- and lower-middle income countries should raise PUHE to provide access to health services for those who are unaffordable individuals.

Upcoming flow promotes the bundle formation of bacterial flagella.

Flagellated bacteria swim by rotating a bundle of helical flagella and commonly explore the surrounding environment in a "run-and-tumble" motility mode. Here, we show that the upcoming flow could impact the bacterial run-and-tumble behavior by affecting the formation and dispersal of the flagellar bundle. Using a dual optical tweezers setup to trap individual bacteria, we characterized the effects of the imposed fluid flow and cell body rotation on the run-and-tumble behavior. We found that the two factors affect the behavior differently, with the imposed fluid flow increasing the running time and decreasing the tumbling time and the cell body rotation decreasing the tumbling time only. Using numerical simulations, we computed the flagellar bundling time as a function of flow velocity, which agrees well with our experimental observations. The mechanical effects we characterized here provide novel, to our knowledge, ingredients for further studies of bacterial chemotaxis in complex environments such as dynamic fluid environments.

The variation of rainfall runoff after vegetation restoration in upper reaches of the Yellow River by the remote sensing technology.

In history, the Yellow River has been suffering from endless floods, which has brought great damage or destruction to agriculture, cities, and people's lives and property along the river. In this study, the rainfall and runoff characteristics of the Yellow River upstream (Tangnaihai and Lanzhou) after the vegetation restoration were analyzed. With the government implementation of ecological restoration policy since 1999, the vegetation cover in this area has been greatly improved and the normalized difference vegetation index (NDVI) shows a fluctuating increase, with the maximum value of 0.323 (in 2010) and the minimum value of 0.289 (in 2008). The trend of rainfall from 1948 to 2019 was increased, with an average increase of 1.747mm per 10 years. Before the implementation of ecological policy (1948 to 1999), the rainfall decreased by an average of 0.953mm per 10 years, and then increased by an average of 16.519mm per 10 years (2000 to 2019). From 1998 to 2017, the runoff increased by 11.13×108m3 per 10 years (Tangnaihai) and 30.517×108 m3 (Lanzhou) per 10 years, which was due to the increase in rainfall. Annual sediment discharge and annual average sediment concentration decreased by 0.002×108t and 0.103 kg/m3 per 10 years in Tangnaihai, 0.081×108t and 0.395kg/m3 per 10 years in Lanzhou respectively. The decreasing intensity of Lanzhou station was greater. The sediment runoff modulus of Tangnaihai and Lanzhou decreased by 1.4875 km2·year and 4.9439 km2·year respectively. The increase of vegetation has a decreasing effect on sediment discharge. The implementation of ecological restoration policy reduces the amount of sediment into the Yellow River and plays an important role in the protection of ecological environment in the Yellow River Basin.

Oleuropein Improved Post Cerebral Stroke Cognitive Function by Promoting Histone Acetylation and Phosphorylation of cAMP Response Element-Binding Protein in MCAO Rats.

BACKGROUND: Post-stroke cognitive impairment (PSCI) is commonest clinical disorder in which peripheral cholinergic activity is important. Oleuropein (OLP) is polyphenol is present in olive oil. Here we evaluated the effect of OLP in cognitive dysfunction rats in post cerebral stroke model. METHODS: The post cerebral stroke cognitive dysfunction PSD rat model was created by occlusion of transient middle cerebral artery. The rats were divided into 6 groups named, Sham + Vehicle, Sham + OLP (50 mg/kg), PSD rats + Vehicle, PSD rats + OLP (20, 50 or 100 mg/kg). The spatial learning was assessed by Morris water maze (MWM). The expression of choline acetyltransferase (ChAT), acetylcholine (ACH), extent of histone acetylation and phosphorylation of cAMP response element-binding protein (CREB) were evaluated by Western blot assay and immunofluorescence staining. RESULTS: Treatment of OLP at various doses showed higher number of spontaneous and rewarded alterations and lesser percentage bias compared to vehicle treated PSD rats. OLP resulted in decreased levels of ChAT and ACH, whereas the degree of histone acetylation and phosphorylation of CREB improved in dose dependent pattern. CONCLUSION: treatment of OLP improved PSCI via increasing the phosphorylation of CREB and histone acetylation, thus attenuating cholinergic activity.

Robustness in an Ultrasensitive Motor.

In Escherichia coli, the chemotaxis response regulator CheY-P binds to FliM, a component of the switch complex at the base of the bacterial flagellar motor, to modulate the direction of motor rotation. The bacterial flagellar motor is ultrasensitive to the concentration of unbound CheY-P in the cytoplasm. CheY-P binds to FliM molecules both in the cytoplasm and on the motor. As the concentration of FliM unavoidably varies from cell to cell, leading to a variation of unbound CheY-P concentration in the cytoplasm, this raises the question whether the flagellar motor is robust against this variation, that is, whether the rotational bias of the motor is more or less constant as the concentration of FliM varies. Here, we showed that the motor is robust against variations of the concentration of FliM. We identified adaptive remodeling of the motor as the mechanism for this robustness. As the level of FliM molecules changes, resulting in different amounts of the unbound CheY-P molecules, the motor adaptively changes the composition of its switch complex to compensate for this effect.IMPORTANCE The bacterial flagellar motor is an ultrasensitive motor. Its output, the probability of the motor turning clockwise, depends sensitively on the occupancy of the protein FliM (a component on the switch complex of the motor) by the input CheY-P molecules. With a limited cellular pool of CheY-P molecules, cell-to-cell variation of the FliM level would lead to large unwanted variation of the motor output if not compensated. Here, we showed that the motor output is robust against the variation of FliM level and identified the adaptive remodeling of the motor switch complex as the mechanism for this robustness.

Joint Resource Optimization in Simultaneous Wireless Information and Power Transfer (SWIPT) Enabled Multi-Relay Internet of Things (IoT) System.

The internet of things (IoT) is becoming more indispensable in modern society as the further development and maturity of information technology progresses. However the exponential growth of IoT devices leads to severe energy consumption. As a technology with broad application prospects, simultaneous wireless information and power transfer (SWIPT) enables IoT devices to harvest energy from receiving radio frequency (RF) signals while ensuring information transmission. In this paper, we investigate the transmission rate optimization problem for a dual-hop multi-relay IoT system, where a decode-and-forward (DF) relay supports the SWIPT technique. We jointly optimize the resource including power and subcarrier allocation, to maximize the system transmission rate. The time-sharing strategy and Lagrange dual method are used to solve this optimization problem. Simulation results reveal that the proposed algorithm has a larger transmission rate than other benchmark algorithms when ensuring each relay has no additional energy supply. Specifically, the proposed algorithm improves the information transmission rate by 2.8%, 3.4% and 43% compared with other algorithms in the case of five relays when the source's power is equal to 0.5 W, respectively.