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In the radio frequency identification technology system, there are too many time slots which are caused by tag collision, and the communication complexity is high. On the basis of the anti-collision algorithm of the binary tree and the quadtree query tree, the methods of locking the collision bit and predicting the child node are used, a new lock-bit hybrid querytree (novel lock-bit hybrid query tree, NLHQT) algorithm is proposed. In the algorithm, the collision bit information is extracted through the lock instruction, and the extracted collision bit information is predicted. While reducing the collision time slot, the reader generates a new query prefix through prediction, thereby avoiding the generation of idle child nodes. Compared with the improved hybrid query tree (IHQT) anti-collision algorithm and the regression lock adaptive multi-tree search (RLAMS), the algorithm in this paper is more effective in reducing the total number of time slots and communication complexity, and the efficiency of identifying tags can be effectively improved.

Cities are in a period of rapid urban development and high-rise buildings are constantly emerging. The characteristics of a fire in a high-rise building are the rapid spread of the fire, the difficulty of fighting the fire, and the difficulty of evacuation. Intelligent fire evacuation requires dynamic planning of paths in fire field, it is necessary to automatically adjust the evacuation route in the building according to the real-time information of the fire. In this paper, an improved bidirectional ant colony algorithm is proposed to optimize fire evacuation routes. In order to improve the global search capability of the algorithm, a bidirectional search strategy with the A* algorithm is designed for the ant colony algorithm, the blindness of the algorithm is reduced in the initial search, the pheromone update strategy is improved, and the convergence speed of the algorithm is increased. The fire scene information is combined with the steering penalty coefficient to improve the algorithm’s evaporation coefficient, heuristic function and transition probability, avoid the risk of falling into the local optimum, improve the search efficiency of the algorithm and the smoothness of the path, and effectively avoid areas affected by the fire. The effectiveness of the algorithm is verified by simulation.

For reduce the high inrush current caused by the low impedance of the resonant tank of LLC resonant converter during the start-up process, this paper proposes a PWM strategy based on the event triggered control (ETC) method. In order to select the trigger event, the segmented state space modeling is used to analyze the relationship between the system state variables and the driving signals. Then, it selects the current and the capacitor voltage in the resonant tank to establish the ETC function to obtain the PWM strategy for the start-up process. When the output voltage is gradually established, the amplitude of the resonant current will be less than the pre-set threshold. Then the resonant capacitor voltage can be used to trigger the event. Finally, by comparing with the experimental results using the traditional soft start-up strategy, the proposed PWM strategy can limit the current and the capacitor voltage in the resonant tank during the start-up process to below the pre-set threshold, while greatly reducing the settling time of output voltage. In addition, the ETC method can achieve smooth switching from the start-up process to the steady state.

Purpose This paper aims to better design the resonant tank parameters for LLC resonant converter. And, it is found that under heavy load, the voltage gain is affected by junction capacitors of the primary side switching and the parasitic parameters of the secondary side diodes converted to the primary side, which will cause the voltage gain decreased when the switching frequency decreased. Design/methodology/approach This paper proposes an optimization parameters design method to solve this problem, which was based on impedance model considering the parasitic parameters of switching devices and diodes. Findings The effectiveness of the proposed method is verified by impedance Bode plots and experimental results. Originality/value From the perspective of impedance modeling, this paper finds the reasons for the insufficient voltage regulation capability of LLC resonant converters under heavy load and finds solutions through analysis.

A simple and robust 36-pulse diode rectifier which consists of a conventional 12-pulse rectifier and a hybrid pulse multiplication interphase reactor (HPM-IPR) is proposed in this article. The HPM-IPR includes a modified interphase reactor (M-IPR), an auxiliary single-phase full-bridge rectifier (ASFBR), and an auxiliary single-phase full-wave rectifier (ASFWR). The ASFBR is connected in series with the load to modulate the output current of the rectifier bridges directly. The ASFWR is connected in parallel to shape the output current of the rectifier bridges indirectly. The conjoint modulation of ASFWR and ASFBR significantly increases the number of output current states of the rectifier bridge, which in turn extends the conventional 12-pulse operation to 36-pulse operation. The proposed 36-pulse diode rectifier draws near the sinusoidal input line currents with THD less than 5%. The kVA ratings of ASFBR and ASFWR are only 1.1% and 1.8% of the output power of the proposed rectifier, respectively, which indicates that the proposed method is suitable for high-power industrial applications. Since only one ASFWR and one ASFBR are adequate, the proposed scheme is low cost, highly reliable, and simple. The detailed analysis is presented, and some experimental results are provided to verify the proposed method.

Antimicrobial peptides (AMPs) or host-defence peptides act by penetrating and disrupting the bacterial membranes and are therefore less prone to antimicrobial resistance (AMR) compared to conventional antibiotics. However, there are still many challenges in the clinical application of the naturally occurring AMPs which necessitates further studies to establish the relationship between the chemical structure of AMPs and their antimicrobial activity and selectivity. Herein, we report a study on the relationship between the chemical structure and the biological activity of a series of rationally designed AMPs derived from Ponericin-W1, a naturally occurring AMP from ants. The peptides were designed by modification of the hydrophobic and hydrophilic regions of the lead peptide sequence in a systematic way. Their antibacterial and hemolytic activities were determined

An important feature of Parkinson’s disease (PD) patients is dyskinesia, and gait signal analysis can provide a strong basis for the diagnosis and rehabilitation of Parkinson’s disease. Traditional machine learning methods are not suitable for directly classifying imbalanced data. In order to accurately distinguish healthy people from Parkinson’s disease patients, a cost-sensitive support vector machine (CS-SVM) method is designed in this paper, which is used to construct the model for classification of gait signals between Kinson’s disease patients and healthy individuals. Gait data for the entire subject was extracted from a real U-shaped electronic walkway. The extracted features are converted to a dimensionless form, the classification performance can be improved. The experimental results show that the prediction accuracy and F-measure obtained by the CS-SVM method are 94.16% and 87.08%, respectively.

APOBEC3A (A3A) is a cytidine deaminase involved in innate immune response and is able to catalyze deamination on both DNA and RNA substrates. It was used in creating the CRISPR-mediated base editor, but has since been held back due to its dual activities. On the other hand, it has been a challenge to separate A3A's dual activities in order to enable it for single-base RNA editors. Here we developed the reporter system for C-to-U RNA editing and employed rational design for mutagenesis to differentiate deaminase activities on RNA and DNA substrates to obtain an RNA-specific editase. Generation and examination of 23 previous A3A mutants showed their deamination activity on RNA was mostly abolished when their activity on DNA was impaired, with the exception of mutant N57Q that displayed an inverse change. We designed new mutations on Loops 1 and 7 based on A3A's crystal structure and found mutants H29R and Y132G had differential effects on catalytic activity on RNA and DNA substrates. In order to engineer an A3A with RNA-specific deaminase activity, we combined Y132G with mutations in Loop 1 or helix 6 by rational design. Two multipoint mutants, Y132G/K30R and Y132G/G188A/R189A/L190A, were successful in retaining high deaminase activity on RNA substrate while eliminating deaminase activity on DNA. We, for the first time, created novel human A3A variants with RNA-specific cytidine deaminase activity, providing insight into A3A's mechanism on substrate recognition and a new addition of a toolset to the creation of a RNA-specific C-to-U base editor.

A simple and robust harmonics reduction scheme for 12-pulse diode rectifier using two auxiliary single-phase full-wave rectifiers (ASFRs) is proposed in this letter. The two ASFRs are installed at the dc side of the rectifier. One ASFR is connected in series with the load to directly modulate the output current of double star rectifiers (DSRs), whereas another ASFR is connected in parallel with the load to indirectly shape the output current of DSRs. The coadjutant modulation of the two ASFRs increases the output current states of DSRs first, thereby increasing the number of steps in the input line currents. This modification extends the conventional 12-step input line current to a 36-step input line current. The proposed rectifier draws near sinusoidal input line currents with the absence of 11th, 13th, 23rd, and 25th harmonics. Since only two ASFRs are sufficient, the proposed rectifier is completely passive and has the least number of component count, making it robust and simple to implement. Analytical results are experimentally verified on 1.8-kW experimental rectifiers.

This paper proposes a four-star 12-pulse diode rectifier with a circulating current shaping circuit CCSC on the DC side to decrease the input current harmonics effectively. The type of circulating current that can eliminate the input current harmonics is analysed and its waveform parameters are derived. The effects of triangular circulating current on the harmonics of the input current are analysed, and the harmonic suppression mechanism of the triangular circulating current is revealed. This scheme has excellent harmonic suppression capability, and the capacity of CCSC is only 2.35% of output power of the 12-pulse rectifier. Thus, this scheme is cost effective for high power applications. The experimental results confirm the theoretical analysis and near sinusoidal input current is obtained.

A simple 24-pulse rectifier combing power electronic phase-shifting transformer (PEPT) and pulse doubling inter-phase reactor (PD-IPR) is presented in this article to reduce the volume/weight of the 12-pulse rectifier. The 24-pulse rectifier which is proposed in this study comprised a PEPT, two three-phase diode bridges and a PD-IPR. The PEPT includes an AC/AC converter and a medium-frequency phase-shifting transformer (MF-PST). The modulation of AC/AC converters facilitates the operation of the MF-SPT in the medium-frequency (MF) state, which can help decrease the volume/weight of the AC/DC converter effectively. The PD-IPR extracts a specific current to multiply the output states of three-phase diode bridges, which, correspondingly, upgrades the 12-pulse rectifier to a novel 24-pulse rectifier. The input line current harmonics are then effectively reduced. The propose 24-pulse rectifier can be control and implement easily because AC/AC converter operates in an open-loop state under 50% duty cycle. The theoretical analysis is verified by simulation results.

Moving target tracking of sensor networks is an important application. The sensor nodes cooperate in the networks to discover the target, and the target’s perceptual information is feeded back to the user. In order to effectively reduce the network energy consumption and improve the tracking quality, a target tracking protocol is proposed based on two-stage sleep scheduling. The whole tracking process is divided into two stages in the protocol. According to the different requirements of node density, the different sleep scheduling mechanism is adopted. In this paper, the proposed protocol is further optimized to ensure the tracking quality while minimizing system energy consumption. Finally, the validity of the proposed protocol was verified with 36 sensor nodes.

The protein p7 in the hepatitis C virus (HCV) is a 63-residue transmembrane protein that oligomerizes to form an ion channel with cation selectivity. This protein is essential for the assembly and ...

Cell behaviors are dictated by epigenetic and transcriptional programs. Little is known about how extracellular stimuli modulate these programs to reshape gene expression and control cell behavioral responses. Here, we interrogated the epigenetic and transcriptional response of endothelial cells to VEGFA treatment and found rapid chromatin changes that mediate broad transcriptomic alterations. VEGFA-responsive genes were associated with active promoters, but changes in promoter histone marks were not tightly linked to gene expression changes. VEGFA altered transcription factor occupancy and the distal epigenetic landscape, which profoundly contributed to VEGFA-dependent changes in gene expression. Integration of gene expression, dynamic enhancer, and transcription factor occupancy changes induced by VEGFA yielded a VEGFA-regulated transcriptional regulatory network, which revealed that the small MAF transcription factors are master regulators of the VEGFA transcriptional program and angiogenesis. Collectively these results revealed that extracellular stimuli rapidly reconfigure the chromatin landscape to coordinately regulate biological responses.

There exists torque ripple in the commutation process of brushless DC motor (BLDCM), which seriously restricts its application in the high-performance field. This paper proposes an auxiliary step-up circuit to suppress the commutation torque ripple of BLDCM, and the auxiliary step-up circuit consists of a transformer, a capacitor and a switch circuit. For effective suppression of the commutation torque ripple, the capacitor is charged in the non-commutation period. When the commutation occurs, the charged capacitor is added on the power source through a switch circuit to step up the dc-bus voltage in the commutation period, and the three-phase inverter is regulated to make the motor’s input voltage is equal to four times the back electromotive force (back EMF) amplitude. The auxiliary step-up circuit only transfers partial power required in the commutation process of the motor, and the capacity of the power components is reduced accordingly. The inductive energy stored in the transformer is returned to the power source in each switching cycle, which improves the energy utilization rate. In addition, this method can also shorten the commutation time. The validity and effectiveness of the proposed method is verified through experimental results.

In the field of model predictive torque control, the problem of weighting factor processing has always attracted attention. Sequential model predictive control which uses two sequential cost functions to select voltage vector shows many advantages in eliminating weighting factor and improving development efficiency. However, its artificially prescribed order of cost functions and the number of selected voltage vectors greatly affect control performance. While keeping the advantages of no weighting factor tuning, this paper proposes a sequential predictive duty cycle control (SPDCC) solution for induction motor drive. The sequential cost function with additional variable parameter is designed to balance better the weighting relationship between electromagnetic torque and stator flux. To improve the effect of the single voltage vector, the duty cycle control based on torque deadbeat is applied in a symmetric manner. The simulation results show the effectiveness of the proposed method.

Due to low cost and high reliability, the Hall-effect sensor is adopted as an alternative to the encoder. This paper presents a pseudo sensorless deadbeat predictive current control (PSDBPCC) method to improve the estimation accuracy of the rotor speed and position with Hall-effect sensors. In this method the output signals of the Hall-effect sensors are transformed to the Hall vector which contains high order harmonics by Clark transformation. The adaptive vectorial filter (AVF) is introduced to extract the fundamental waves of the Hall vector. The rotor speed and position are estimated from the fundamental waves with an improved phase locked loop (PLL) structure. Compared with the conventional method, the proposed method has higher estimation accuracy in steady state and better dynamic tracking performance. The experimental results verify the effectiveness of the proposed method.

Model predictive current control has received a great deal of attention in the field of induction motor drives. However, the most methods select voltage vectors based on enumeration and cost function, so it greatly increases control system complexity. In order to reduce control complexity and further improve steady-state control performance, a predictive current duty cycle control based on the reference voltage (PCDCC-RV) is proposed in this paper. The applied voltage vector is determined based on the location of the synthesized reference voltage, so the complicated enumeration process is cancelled. In addition, the control duty cycle is calculated based on the principle of minimum error between the selected vector and reference voltage. Compared with the traditional method, the proposed method of voltage vector selection and duty cycle calculation are more convenient, and the better control performance is obtained. Finally, simulation results prove its effectiveness.

The initial coin offering (ICO) market relies on the “wisdom of crowds”, ratings given by the collective opinion of crypto experts, to overcome asymmetric information problems in the fundraising process. We investigate the biases of crypto experts in providing ratings in ICOs. We conjecture that experts are incentivized to provide optimistic ratings to promote ICO fundraising success due to their future opportunities as advisors in subsequent ICOs. We examine our conjectures using ICO ratings on ICOBench.com during the period of 2016 to 2019. Consistent with our conjectures, we find that expert ratings in ICOs exhibit systematic optimism relative to the algorithm-generated objective ratings, and experts who give optimistic ratings to a greater number of fundraising successful ICOs are more likely to be hired as advisors in subsequent ICOs. Further, we find that ICOs with more optimistic expert ratings and ICOs hiring experts as advisors are associated with greater likelihood of fundraising success but not that of exchange listing and one-year survival. We interpret our findings to suggest that the incentive of crypto experts to be hired as ICO advisors and the associated optimism in their ratings help ICO startups raise funds but do not help crypto investors in achieving competitive outcome.

Soft start-up is necessary for LLC converter to avoid high inrush current. In this paper, an event trigger control (ETC) method for the start-up process is proposed. It firstly establishes the piecewise state space model, which can reveal the relationship between resonant capacitor voltage and resonant current during start-up. And then an event-trigger function is established to control the switching state according to the model. Experimental results verify that the proposed method can successfully limit the peak current to be the pre-setting current during the start-up process and that the build-up time of output voltage can be reduced. The biggest advantage of the ETC method is smoothly transition between the start-up and steady state.

We constructed complex models of SARS-CoV-2 spike protein binding to pangolin or human ACE2, the receptor for virus transmission, and estimated the binding free energy changes using molecular dynamics simulation. SARS-CoV-2 can bind to both pangolin and human ACE2, but has a significantly lower binding affinity for pangolin ACE2 due to the increased binding free energy (9.5 kcal mol−1). Human ACE2 is among the most polymorphous genes, for which we identified 317 missense single-nucleotide variations (SNVs) from the dbSNP database. Three SNVs, E329G (rs143936283), M82I (rs267606406) and K26R (rs4646116), had a significant reduction in binding free energy, which indicated higher binding affinity than wild-type ACE2 and greater susceptibility to SARS-CoV-2 infection for people with them. Three other SNVs, D355N (rs961360700), E37K (rs146676783) and I21T (rs1244687367), had a significant increase in binding free energy, which indicated lower binding affinity and reduced susceptibility to SARS-CoV-2 infection.

The present study aimed to investigate the roles of Ropivacaine in papillary thyroid cancer (PTC) and identify the possible mechanisms. The expression of integrin alpha-2 (ITGA2) in TC cell lines was tested using Western blotting and RT-qPCR. Subsequently, the level of ITGA2 in human PTC cell line (TPC-1) was measured following intervention with a series of concentrations of Ropivacaine. Then, cell counting kit-8 (CCK-8) assay and colony formation assay were executed for detecting proliferation of cells after transfection with ITGA2 pcDNA3.1. The expression of proliferation-related protein was determined by Western blotting. Additionally, the abilities of TPC-1 cell invasion and migration were examined using Transwell assay and scratch wound healing assay. Apoptosis of TPC-1 cells was analyzed using TUNEL assay and the expressions of apoptosis-related proteins were tested via West blotting. The results suggested that ITGA2 was highly expressed in TC cell lines, especially in TPC-1 cells. Ropivacaine decreased the expression of ITGA2 in a dose-dependent manner. Moreover, after treatment with Ropivacaine, cell proliferation was inhibited accompanied by changes of proliferation-related protein expressions, which was reversed following co-transfection with ITGA2 pcDNA3.1. Furthermore, Ropivacaine concentration-dependently suppressed invasion and migration of TPC-1 cells, whereas these inhibitory effects were attenuated after ITGA2 overexpression. Furthermore, apoptosis was promoted, coupled with a decrease of Bcl-2 expression and increases of Bax, cleaved caspase-3 and cleaved caspase-9 expression, in Ropivacaine-treated TPC-1 cells, which was restored following ITGA2 overexpression. These findings demonstrated that Ropivacaine could suppress proliferation, invasion, migration, and accelerate apoptosis of PTC cells via regulating ITGA2 expression.

Coronavirus Disease 2019 (COVID-19) is an ongoing global health emergency that has caused tremendous stress and loss of life worldwide. The viral spike glycoprotein is a critical molecule mediating transmission of SARS-CoV-2 by interacting with human ACE2. However, through the course of the pandemics, there has not been a thorough analysis of the spike protein mutations, and on how these mutants influence the transmission of SARS-CoV-2. Besides, cases of SARS-CoV-2 infection among pets and wild animals have been reported, so the susceptibility of these animals requires great attention to investigate, as they may also link to the renewed question of a possible intermediate host for SARS-CoV-2 before it was transmitted to humans. With over 226,000 SARS-CoV-2 sequences obtained, we found 1573 missense mutations in the spike gene, and 226 of them were within the receptor-binding domain (RBD) region that directly interacts with human ACE2. Modeling the interactions between SARS-CoV-2 spike mutants and ACE2 molecules showed that most of the 74 missense mutations in the RBD region of the interaction interface had little impact on spike binding to ACE2, whereas several within the spike RBD increased the binding affinity toward human ACE2 thus making the virus likely more contagious. On the other hand, modeling the interactions between animal ACE2 molecules and SARS-CoV-2 spike revealed that many pets and wild animals' ACE2 had a variable binding ability. Particularly, ACE2 of bamboo rat had stronger binding to SARS-CoV-2 spike protein, whereas that of mole, vole, Mus pahari, palm civet, and pangolin had a weaker binding compared to human ACE2. Our results provide structural insights into the impact on interactions of the SARS-CoV-2 spike mutants to human ACE2, and shed light on SARS-CoV-2 transmission in pets and wild animals, and possible clues to the intermediate host(s) for SARS-CoV-2.