Channel assignment and power allocation for throughput improvement with PPO in B5G heterogeneous edge networks

In Beyond the Fifth Generation(B5G)heterogeneous edge networks,numerous users are multiplexed on a channel or served on the same frequency resource block,in which case the transmitter applies coding and the receiver uses interference cancellation.Unfortunately,uncoordinated radio resource allocation can reduce system throughput and lead to user inequity,for this reason,in this paper,channel allocation and power allocation problems are formulated to maximize the system sum rate and minimum user achievable rate.Since the construction model is non-convex and the response variables are high-dimensional,a distributed Deep Reinforcement Learning(DRL)framework called distributed Proximal Policy Optimization(PPO)is proposed to allocate or assign resources.Specifically,several simulated agents are trained in a heterogeneous environment to find robust behaviors that perform well in channel assignment and power allocation.Moreover,agents in the collection stage slow down,which hinders the learning of other agents.Therefore,a preemption strategy is further proposed in this paper to optimize the distributed PPO,form DP-PPO and successfully mitigate the straggler problem.The experimental results show that our mechanism named DP-PPO improves the performance over other DRL methods.

Exploring the psychological impact of the 2022 SARS-CoV-2 Omicron variant outbreak in China

To the editor:The impact of the coronavirus disease 2019(COVID-19)pandemic in 2020 on mental health was substantialin Chinai2and various other countries.34 Beyond the direct consequences of COVID-19,the pandemic created an environment in which many determinants of mental health were affected.Issues associated with the pandemic,such as loss of livelihood,limited access to medical services,reduced social interactions,and economic downturn,could potentially have adverse effects on the population's mental well-being.5 In November 2021,the World Health Organization(WHO)designated the new variant of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),variant B.1.1.529,as a variant of concern and named it Omicron;its rapid mutation and spread raised a new global health concern.

Improving Federated Learning through Abnormal Client Detection and Incentive

Data sharing and privacy protection are made possible by federated learning,which allows for continuous model parameter sharing between several clients and a central server.Multiple reliable and high-quality clients must participate in practical applications for the federated learning global model to be accurate,but because the clients are independent,the central server cannot fully control their behavior.The central server has no way of knowing the correctness of the model parameters provided by each client in this round,so clients may purposefully or unwittingly submit anomalous data,leading to abnormal behavior,such as becoming malicious attackers or defective clients.To reduce their negative consequences,it is crucial to quickly detect these abnormalities and incentivize them.In this paper,we propose a Federated Learning framework for Detecting and Incentivizing Abnormal Clients(FL-DIAC)to accomplish efficient and security federated learning.We build a detector that introduces an auto-encoder for anomaly detection and use it to perform anomaly identification and prevent the involvement of abnormal clients,in particular for the anomaly client detection problem.Among them,before the model parameters are input to the detector,we propose a Fourier transform-based anomaly data detectionmethod for dimensionality reduction in order to reduce the computational complexity.Additionally,we create a credit scorebased incentive structure to encourage clients to participate in training in order tomake clients actively participate.Three training models(CNN,MLP,and ResNet-18)and three datasets(MNIST,Fashion MNIST,and CIFAR-10)have been used in experiments.According to theoretical analysis and experimental findings,the FL-DIAC is superior to other federated learning schemes of the same type in terms of effectiveness.

Enrichment of beneficial cucumber rhizosphere microbes mediated by organic acid secretion

Resistant cultivars have played important roles in controlling Fusarium wilt disease,but the roles of rhizosphere interactions among different levels of resistant cultivars are still unknown.Here,two phenotypes of cucumber,one resistant and one with increased susceptibility to Fusarium oxysporum f.sp.cucumerinum(Foc),were grown in the soil and hydroponically,and then 16S rRNA gene sequencing and nontargeted metabolomics techniques were used to investigate rhizosphere microflora and root exudate profiles.Relatively high microbial community evenness for the Foc-susceptible cultivar was detected,and the relative abundances of Comamonadaceae and Xanthomonadaceae were higher for the Foc-susceptible cultivar than for the other cultivar.FishTaco analysis revealed that specific functional traits,such as protein synthesis and secretion,bacterial chemotaxis,and small organic acid metabolism pathways,were significantly upregulated in the rhizobacterial community of the Foc-susceptible cultivar.A machinelearning approach in conjunction with FishTaco plus metabolic pathway analysis revealed that four organic acids(citric acid,pyruvate acid,succinic acid,and fumarate)were released at higher abundance by the Foc-susceptible cultivar compared with the resistant cultivar,which may be responsible for the recruitment of Comamonadaceae,a potential beneficial microbial group.Further validation demonstrated that Comamonadaceae can be“cultured”by these organic acids.Together,compared with the resistant cultivar,the susceptible cucumber tends to assemble beneficial microbes by secreting more organic acids.

QuEChERS-超高效液相色谱-串联质谱法同时测定双壳类水产品中40种药物及个人护理品的残留量

建立了以QuEChERS作为前处理技术,结合高效液相色谱-串联质谱技术(HPLC-MS/MS)检测双壳类水产品中40种药物及个人护理品的检测方法。样品经乙腈提取,PSA和C18净化,采用ACQUITY UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm)分离,以甲醇和0.1%甲酸水溶液作为流动相进行梯度洗脱,经电喷雾正离子电离及多反应监测模式来测定目标化合物,采用基质匹配标准溶液曲线法进行定量。结果表明,40种药物及个人护理品在0.5—100μg·L^(−1)浓度范围内线性关系良好,相关系数均大于0.99,检出限为0.04—6μg·kg^(−1),定量限为0.1—19μg·kg^(−1)。对空白样品进行3个水平的加标回收实验,平均回收率在76.9%—110%范围内,相对标准偏差为1.2%—9.5%。该方法前处理方法快速、简便、灵敏度高,适用于双壳类水产品中多种药物及个人护理品残留的同时测定。

Anthrazoline Photocatalyst for Promoting Esterification and Etherification Reactions via Photoredox/Nickel Dual Catalysis

Here,we demonstrate a readily prepared anthrazoline photocatalyst,which can effectively promote C—O bond formation reactions with the aid of Ni(II)complex.This methodology enables the esterification(36 examples)and etherification(8 examples)with a broad range of scope,allowing aryl and alkyl halides coupled with diverse carboxylic acids/alcohols.Our metal-free photocatalysts have a potential broad application,may serve as an alternative to some iridium and ruthenium based photocatalysts,and are of potential importance to the pharmaceutical industry.

Imaging and Spectral Characteristics of Amyloid Plaque Autofluorescence in Brain Slices from the APP/PS1 Mouse Model of Alzheimer’s Disease

Amyloid deposits are one of the hallmark pathological lesions of Alzheimer's disease(AD). They can be visualized by thioflavin-S, silver impregnation,Congo red staining, and immunohistochemical reactions.However, that amyloid deposits generate blue autofluorescence(auto-F) has been ignored. Here, we report that visible light-induced auto-F of senile plaques(SPs) was detected and validated with conventional methods. Brain slices from APP/PS1(amyloid precursor protein/presenilin1) transgenic mice were mounted on slides, rinsed,coverslipped and observed for details of the imaging and spectral characteristics of the auto-F of SPs. Then the slices were treated with the above classic methods for comparative validation. We found that the SP auto-F was greatest under blue-violet excitation with a specific emission spectrum, and was much easier, more sensitive, and reliable than the classic methods. Because it does not damage slices, observation of auto-F can be combined with all post-staining techniques in slices and for brain-wide imaging in AD.

Ground state solutions for a class of fractional Kirchhoff equations with critical growth

In this paper, we study the effect of lower order perturbations in the existence of positive solutions to the fractional Kirchhoff equation with critical growth■ where a, b > 0 are constants, μ > 0 is a parameter,■ , and V : R^3→ R is a continuous potential function. For suitable assumptions on V, we show the existence of a positive ground state solution, by using the methods of the Pohozaev-Nehari manifold, Jeanjean's monotonicity trick and the concentration-compactness principle due to Lions(1984).

Sand-mediated ice seeding enables serum-free low-cryoprotectant cryopreservation of human induced pluripotent stem cells

Human induced pluripotent stem cells(hiPSCs)possess tremendous potential for tissue regeneration and banking hiPSCs by cryopreservation for their ready availability is crucial to their widespread use.However,contemporary methods for hiPSC cryopreservation are associated with both limited cell survival and high concentration of toxic cryoprotectants and/or serum.The latter may cause spontaneous differentiation and/or introduce xenogeneic factors,which may compromise the quality of hiPSCs.Here,sand from nature is discovered to be capable of seeding ice above10◦C,which enables cryopreservation of hiPSCs with no serum,much-reduced cryoprotectant,and high cell survival.Furthermore,the cryopreserved hiPSCs retain high pluripotency and functions judged by their pluripotency marker expression,cell cycle analysis,and capability of differentiation into the three germ layers.This unique sand-mediated cryopreservation method may greatly facilitate the convenient and ready availability of high-quality hiPSCs and probably many other types of cells/tissues for the emerging cell-based translational medicine.

INTERIOR PENALTY BILINEAR IFE DISCONTINUOUS GALERKIN METHODS FOR ELLIPTIC EQUATIONS WITH DISCONTINUOUS COEFFICIENT

This paper applies bilinear immersed finite elements （IFEs） in the interior penalty discontinuous Galerkin （DG） methods for solving a second order elliptic equation with discontinuous coefficient. A discontinuous bihnear IFE space is constructed and applied to both the symmetric and nonsymmetric interior penalty DG formulations. The new methods can solve an interface problem on a Cartesian mesh independent of the interface with local refinement at any locations needed even if the interface has a nontrivial geometry. Numerical examples are provided to show features of these methods.

Rock inhibitor may compromise human induced pluripotent stem cells for cardiac differentiation in 3D

Cardiomyocytes differentiated from human induced pluripotent stem cells(iPSCs)are valuable for the understanding/treatment of the deadly heart diseases and their drug screening.However,the very much needed homogeneous 3D cardiac differentiation of human iPSCs is still challenging.Here,it is discovered surprisingly that Rock inhibitor(RI),used ubiquitously to improve the survival/yield of human iPSCs,induces early gastrulation-like change to human iPSCs in 3D culture and may cause their heterogeneous differentiation into all the three germ layers(i.e.,ectoderm,mesoderm,and endoderm)at the commonly used concentration(10μM).This greatly compromises the capacity of human iPSCs for homogeneous 3D cardiac differentiation.By reducing the RI to 1μM for 3D culture,the human iPSCs retain high pluripotency/quality in inner cell mass-like solid 3D spheroids.Consequently,the beating efficiency of 3D cardiac differentiation can be improved to more than 95%in~7 days(compared to less than~50%in 14 days for the 10μM RI condition).Furthermore,the outset beating time(OBT)of all resultant cardiac spheroids(CSs)is synchronized within only 1 day and they form a synchronously beating 3D construct after 5-day culture in gelatin methacrylol(GelMA)hydrogel,showing high homogeneity(in terms of the OBT)in functional maturity of the CSs.Moreover,the resultant cardiomyocytes are of high quality with key functional ultrastructures and highly responsive to cardiac drugs.These discoveries may greatly facilitate the utilization of human iPSCs for understanding and treating heart diseases.

QoE-Driven Big Data Management in Pervasive Edge Computing Environment

In the age of big data, services in the pervasive edge environment are expected to offer end-users better Quality-of-Experience(QoE) than that in a normal edge environment. However, the combined impact of the storage, delivery, and sensors used in various types of edge devices in this environment is producing volumes of high-dimensional big data that are increasingly pervasive and redundant. Therefore, enhancing the QoE has become a major challenge in high-dimensional big data in the pervasive edge computing environment. In this paper, to achieve high QoE, we propose a QoE model for evaluating the qualities of services in the pervasive edge computing environment. The QoE is related to the accuracy of high-dimensional big data and the transmission rate of this accurate data. To realize high accuracy of high-dimensional big data and the transmission of accurate data through out the pervasive edge computing environment, in this study we focused on the following two aspects.First, we formulate the issue as a high-dimensional big data management problem and test different transmission rates to acquire the best QoE. Then, with respect to accuracy, we propose a Tensor-Fast Convolutional Neural Network(TF-CNN) algorithm based on deep learning, which is suitable for high-dimensional big data analysis in the pervasive edge computing environment. Our simulation results reveal that our proposed algorithm can achieve high QoE performance.

Bifurcation and multiplicity of positive solutions for nonhomogeneous fractional Schrödinger equations with critical growth

In this paper we study the nonhomogeneous semilinear fractional Schr?dinger equation with critical growth{(−∆)su + u = u^2∗s−1 + λ(f(x, u) + h(x)), x ∈ R^N ,u ∈ Hs(R^N ), u(x) > 0, x ∈ RN ,where s∈(0,1),N>4 s,andλ>0 is a parameter,2s*=2 N/N-2 s is the fractional critical Sobolev exponent,f and h are some given functions.We show that there exists 0<λ*<+∞such that the problem has exactly two positive solutions ifλ∈(0,λ*),no positive solutions forλ>λ*,a unique solution(λ*,uλ*)ifλ=λ*,which shows that(λ*,uλ*)is a turning point in Hs(RN)for the problem.Our proofs are based on the variational methods and the principle of concentration-compactness.

Noncovalent reversible binding-enabled facile fabrication of leak-free PDMS microfluidic devices without plasma treatment for convenient cell loading and retrieval

The conventional approach for fabricating polydimethylsiloxane(PDMS)microfluidic devices is a lengthy and inconvenient procedure and may require a clean-room microfabrication facility often not readily available.Furthermore,living cells can’t survive the oxygen-plasma and high-temperature-baking treatments required for covalent bonding to assemble multiple PDMS parts into a leak-free device,and it is difficult to disassemble the devices because of the irreversible covalent bonding.As a result,seeding/loading cells into and retrieving cells from the devices are challenging.Here,we discovered that decreasing the curing agent for crosslinking the PDMS prepolymer increases the noncovalent binding energy of the resultant PDMS surfaces without plasma or any other treatment.This enables convenient fabrication of leak-free microfluidic devices by noncovalent binding for various biomedical applications that require high pressure/flow rates and/or long-term cell culture,by simply hand-pressing the PDMS parts without plasma or any other treatment to bind/assemble.With this method,multiple types of cells can be conveniently loaded into specific areas of the PDMS parts before assembly and due to the reversible nature of the noncovalent bonding,the assembled device can be easily disassembled by hand peeling for retrieving cells.Combining with 3D printers that are widely available for making masters to eliminate the need of photolithography,this facile yet rigorous fabrication approach is much faster and more convenient for making PDMS microfluidic devices than the conventional oxygen plasma-baking-based irreversible covalent bonding method.

Immersed Finite Element Method for Interface Problems with Algebraic Multigrid Solver

This article is to discuss the bilinear and linear immersed finite element(IFE)solutions generated from the algebraic multigrid solver for both stationary and moving interface problems.For the numerical methods based on finite difference formulation and a structured mesh independent of the interface,the stiffness matrix of the linear system is usually not symmetric positive-definite,which demands extra efforts to design efficient multigrid methods.On the other hand,the stiffness matrix arising from the IFE methods are naturally symmetric positive-definite.Hence the IFE-AMG algorithm is proposed to solve the linear systems of the bilinear and linear IFE methods for both stationary and moving interface problems.The numerical examples demonstrate the features of the proposed algorithms,including the optimal convergence in both L 2 and semi-H1 norms of the IFE-AMG solutions,the high efficiency with proper choice of the components and parameters of AMG,the influence of the tolerance and the smoother type of AMG on the convergence of the IFE solutions for the interface problems,and the relationship between the cost and the moving interface location.