BIODEGRADABLE POLYMERS WITH A PHOSPHORYL-CONTAINING BACKBONE:TISSUE ENGINEERING AND CONTROLLED DRUG DELIVERY APPLICATIONS

This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Many areas warrantfurther investigation and much optimization remains to be done. The fascinatingchemistry of phosphorus poses interesting hurdles but at the same time leavesample room for polymer scientists to exercise their creativity in designinginteresting biomaterials. As the mutual understanding between basic and clinicalscientists on the need of medical devices and the capabilities of these newbiomaterials expands, imaginative application of new biomaterials to other medi-cal applications can be expected.

基于Backbone的极值进化算法

由于变量的适应度最优与问题的目标函数最优无法达到一致,从而利用极值过程原则的局部搜索算法对TSP问题效果不好,而通过改变变量的适应度,使其与目标函数相关,就能够提高个体解的搜索能力。比较参数取不同值时个体解搜索到的目标函数,可以发现存在使个体解搜索性能最佳的参数取值,且与变量的变异方式无关,这就为参数设置提供了依据。但个体解接近最优解后改善缓慢,无法快速到达最优解,为此引入组合优化问题解的Backbone概念,在种群进入最优解域后固定解中的相同部分,从而保留解中包含的最优解的信息,在减小问题规模后继续进行优化,增强搜索能力,提高搜索性能。

基于Backbone的空间收缩与划分算法

搜索空间的规模和复杂程度是决定问题求解难度的重要因素,而解空间的信息往往可以引导搜索找到最优解。在已知JSP空间结构的基础上,提出一种空间收缩与划分算法。算法利用搜索算法获得的较优解,结合组合优化问题解的backbone的概念,将搜索空间收缩并划分为一个或多个优解域,在优解域内再进行小规模问题的优化。该算法不必在求解前或求解过程中进行大量的统计分析工作,可以利用求解信息对解空间的地形进行估计,提高求解速度和解的质量。实验结果也证明了算法的有效性。

Parameterless Pruning Algorithms for Similarity-Weight Network and Its Application in Extracting the Backbone of Global Value Chain

Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualization,ICIO networks with tremendous low-weight edges are too dense to show the substantial structure.These redundant edges,inevitably make the network data full of noise and eventually exert negative effects on Social Network Analysis(SNA).In this case,we need a method to filter such edges and obtain a sparser network with only the meaningful connections.Design/methodology/approach:In this paper,we propose two parameterless pruning algorithms from the global and local perspectives respectively,then the performance of them is examined using the ICIO table from different databases.Findings:The Searching Paths(SP)method extracts the strongest association paths from the global perspective,while Filtering Edges(FE)method captures the key links according to the local weight ratio.The results show that the FE method can basically include the SP method and become the best solution for the ICIO networks.Research limitations:There are still two limitations in this research.One is that the computational complexity may increase rapidly while processing the large-scale networks,so the proposed method should be further improved.The other is that much more empirical networks should be introduced to testify the scientificity and practicability of our methodology.Practical implications:The network pruning methods we proposed will promote the analysis of the ICIO network,in terms of community detection,link prediction,and spatial econometrics,etc.Also,they can be applied to many other complex networks with similar characteristics.Originality/value:This paper improves the existing research from two aspects,namely,considering the heterogeneity of weights and avoiding the interference of parameters.Therefore,it provides a new idea for the research of network backbone extraction.

Backbone formulation algorithm in wireless sensor network based on cross-entropy method

In wireless sensor network,virtual backbone is a cost effective broadcasting method.Connected dominating set formation is proposed to construct a virtual backbone.However,it is NP-Hard to find a minimum connected dominating set in an arbitrary graph.In this paper,based on cross-entropy method,we present a novel backbone formulation algorithm(BFA-CE)in wireless sensor network.In BFA-CE,a maximal independent set is got at first and nodes in the independent set are required to get their action sets.Based on those action sets,a backbone is generated with the cross-entropy method.Simulation results show that our algorithm can effectively reduce the size of backbone network within a reasonable message overhead,and it has lower average node degree.This approach can be potentially used in designing efficient broadcasting strategy or working as a backup routing of wireless sensor network.

A Distributed Virtual Backbone Formation for Wireless Ad Hoc and Sensor Networks

The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless networks. The quality of a virtual backbone is measured not only by approximation factor, which is the ratio of its size to that of minimum CDS, but also time complexity and message complexity. In this paper, a distributed algorithm is presented to construct a minimum CDS for ad hoc and sensor networks. By destroying triangular loops in the virtual backbone, the proposed algorithm can effectively construct a CDS with smaller size. Moreover, our algorithm, which is fully localized, has a constant approximation ratio, linear message and time complexity, and low implementation complexity. The simulation results and theoretical analysis show that our algorithm has better efficiency and performance than conventional approaches.

A Study of Configuration Evolution of an Operational IP Backbone Network

Configuration errors are proved to be the main reasons for network interruption and anomalies.Many researchers have paid their attention to configuration analysis and provisioning,but few works focus on understanding the configuration evolution.In this paper,we uncover the configuration evolution of an operational IP backbone based on the weekly reports gathered from January 2006 to January 2013.We find that rate limiting and launching routes for new customers are configured most frequently.In addition,we conduct an analysis of network failures and find that link failures are the main causes for network failures.We suggest that we should configure redundant links for the links which are easy to break down.At last,according to the analysis results,we illustrate how to provide semi-automated configuration for rate limiting and adding customers.

Selective Acid Hydrolysis Condition for the Composition and Linkage with a Fructofuranosyl Backbone of a Polysaccharide from Angelica sinensis (Oliv) Diels

A new polysaccharide was extracted and purified from the roots of Angelica sinensis （Oliv） Diels （ASD）. Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The polysaccharide was made of → 1） Fruf（2→and→6） Glcp （l→as its backbone with highly branched structure. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the roots of the ASD.

Fractals of Protein Backbone Structures

Ths paper，based on the principles of geometric self-similarity of fractal theory and some research results of rotein chemistry，improved the method of comput－ing protein fractal dimensions，and computed fractal dimensions of some protein back bone，secondary and assumed folding structures．The relationship between protein back-bone strucrural fractal dimensions and its spatial structures was investigated．The results indicated that protein backbone fractal dimensions not only have a close relation with protein secondary structure，but also with its folding．In addition，the folding of protein Polypeptide chains in 3-D space may be similar to the other macromolecular chain be haviour described by the self-avoiding walks（SAW）model．

Method of Distribution Network Resources after Restoration, the Networks MPLS-TE Use of Various Telecommunications Technologies to Construct Backbone Networks

The modern telecommunication system is characterized by the rapid improvement of information and communication technologies, such as the improvement in the data rate, power consumption and Quality of Service (QoS). Based on this development, the next generation network (NGN) is shaped. The NGN is represented by a packet transport network demarcated functions and services. To provide transport functions in NGN, using Multi-Protocol Label Switching (MPLS) technology, there are two main problems, which are multipath routing and traffic distribution, which are what this paper works with. Accordingly, this paper proposes a solution to these two problems using optimization procedures to find the shortest path Dijkstra and Bellman-Ford, which is characterized by a high-speed-oriented selection of a single shortest path between the source and the destination, based on several selected criteria related to the optimal use of the network resources. Solving the information flow distribution problems in large number of nodes network applying salesman procedure or having NP-completeness, causes significant time delay, which means that the proposed solution is not suitable for real time applications. Accordingly, for real time applications, there is a need to move to other methods based on the use of several independent shortest paths.

The need analysis of backbone civilian nurses post-oriented education training in China

To learn about the need of post-oriented education training of backbone civilian nurses,and to provide scientific evidence for the promotion of training. Methods The convenience sampling method was performed,and an anonymous survey on 324 nurses who participated in the "backbone civilian nurses training program"from September 2013 to October 2015 was carried out by using self-made questionnaire.Results(1)Among the 324 nurses,12. 04% of them volunteered to participate in the training and 87. 96%were sent by their departments.(2)More than 90% of training contents met their needs.(3)The training methods in demand included theoretical classroom teaching,clinical observation and probation,seminars,clinical management practice,clinical problem discussion and clinical nursing practice(4)The training period suggested by most nurses was about 2 to 4 weeks. Conclusion It is important to strengthen the significance of post-oriented education training and to improve the quality and capacity of civilian through scientific education design and practical training programs.

Gateways Placement in Backbone Wireless Mesh Networks

This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint, relay load constraint and gateway capacity constraint. Experimental results show that its performance is as good as that of the best of existing algorithms for the gateway placement problem. But, the new algorithm can be used for BWMNs that do not form one connected component, and it is easy to implement and use.

Essential Topics on Constructing WCDS-based Virtual Backbone in Wireless Sensor/Mesh Networks

Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.

More precise model of <i>α</i>-helix and transmembrane <i>α</i>-helical peptide backbone structure

The 3-D structure of the β-adrenergic receptor with a molecular weight of 55,000 daltons is available from crystallographic data. Within one of the seven transmembrane ion channel helices in the β2-receptor, one loop of a helix ACADL has previously been proposed as the site that explains β2 activity (fights acute bronchitis) whereas ASADL in the β1-receptor at the corresponding site explains β1-activity (cardiac stimulation). The α-agonist responsible for this selective reaction is only 0.5% of the receptor molecular weight, and only 1.5% of the weight of the trans-membrane portion of the receptor. The understanding of the mechanism by which a small molecule on binding to a site on one single loop of a helix produces a specific agonist activity on an entire transmembrane ion channel is uncertain. A model of an α-helix is presented in which of pitch occurs at angles both smaller and larger than 180° n. Consequently, atomic coordinates in a peptide backbone α-helix match the data points of individual atom (and atom types) in the backbone. More precisely, eleven atoms in peptide backbone routinely equal one loop of a helix, instead of eleven amino acid residues equaling three loops of a helix;therefore, an α-helix can begin (or end) at any specific atom in a peptide backbone, not just at any specific amino acid. Wavefront Topology System and Finite Element Methods calculate this specific helical shape based only upon circumference, pitch, and phase. Only external forces which specifically affect circumference, pitch and/or phase (e.g. from agonist binding) can/will alter the shape of an α-helix.

Software-Defined Space-Air-Ground Integrated Network Architecture with the Multi-Layer Satellite Backbone Network

Under the background of the rapid development of ground mobile communication,the advantages of high coverage,survivability,and flexibility of satellite communication provide air support to the construction of space information network.According to the requirements of the future space information communication,a software-defined Space-Air-Ground Integrated network architecture was proposed.It consisted of layered structure satellite backbone network,deep space communication network,the stratosphere communication network and the ground network.The Space-Air-Ground Integrated network was supported by the satellite backbone network.It provided data relay for the missions such as deep space exploration and controlled the deep-space spacecraft when needed.In addition,it safeguarded the anti-destructibility of stratospheric communication and assisted the stratosphere to supplement ground network communication.In this paper,algorithm requirements of the congestion control and routing of satellite backbone protocols for heterogeneous users’services were proposed.The algorithm requirements of distinguishing different service objects for the deep space communication and stratospheric communication network protocols were described.Considering the realistic demand for the dynamic coverage of the satellite backbone network and node cost,the multi-layer satellite backbone network architecture was constructed.On this basis,the proposed Software-defined Space-Air-Ground Integrated network architecture could be built as a large,scalable and efficient communication network that could be integrated into space,air,and ground.

MODELLING THE POLYALANINE BACKBONE STARTING FROM ALPHA-CARBON GUIDE POSITIONS

An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here,which is different from a previously developed'spare parts'approach(Jones and Thirup,1986;Claessens et al.,1989). In our procedure,the geometric restraint of angle N-CA-C is used to generate a list of polypeptide chains,and several filters are used later to select the best conformer.The most important filter is based upon the Ramachandran scatter plot of mainchain dihedral angles PHI and PSI.Results for all test cases are satisfactory,with more than 95%of peptide planes correctly reconstructed and the overall root-mean-square deviation less than 0.5 angstrom compared with the refined X-ray coordinates.

Provider Backbone Transport Technology

The Metro Ethernet Forum(MEF) put forward the concept of Carrier Ethernet(CE) to improve Ethernet technology and make it a transmission convergence layer solution for Next Generation Network(NGN).Provider Backbone Transport(PBT) is the result of the enhancement and improvement of the early Ethernet technologies and it is the new version of CE implementation technology and standard which is promising.Through studying the PBT-related technologies,PBT network structure,PBT advantages as the transmission convergence layer solution and its trend of future development,it is concluded that PBT can be used as the preferred technology of the transmission convergence layer in the NGN,though there are some problems to be solved for PBT.

Interaction of Al-induced peptide backbone ring structure with the sidechains of His, Phe, Trp and Tyr

Aluminium is widely used as an antimicrobial coagulant,food additive,and cookware.However,many reports indicate that aluminium may be a critical factor in many amyloid diseases,such as Alzheimer’s disease and Parkinson’s disease.Unfortunately,the underlying mechanism is still poorly understood,which limits efforts to prevent and treat these diseases.In this paper,using an ab initio method,we studied the interaction of Al-backbone ring structure with theπ-electron-rich sidechains of His,Phe,Trp,and Tyr.We found that in the absence of water,the Al-backbone ring can stably bind with those sidechains.In the presence of water,the Al-backbone ring can bind to the His sidechain and cannot bind to the other sidechains.As revealed by further investigations,this could be attributed to the fact that there was a coordinate bond of the Al-backbone ring with the His sidechain,while there were theπ-πstacking and cation-π-like interactions with the other sidechains.These findings potentially provide a molecular understanding of Al-related toxicity,and may be helpful in designing drugs for those aforementioned aluminum-linked diseases and encourage treatment of Al-polluted water.

引入上下文信息和Attention Gate的GUS-YOLO遥感目标检测算法

目前基于通用YOLO系列的遥感目标检测算法存在并未充分利用图像的全局上下文信息,在特征融合金字塔部分并未充分考虑缩小融合特征之间的语义鸿沟、抑制冗余信息干扰的缺点。在结合YOLO算法优点的基础上提出GUS-YOLO算法,其拥有一个能够充分利用全局上下文信息的骨干网络Global Backbone。除此之外,该算法在融合特征金字塔自顶向下的结构中引入Attention Gate模块,可以突出必要的特征信息,抑制冗余信息。另外,为Attention Gate模块设计了最佳的网络结构,提出了网络的特征融合结构U-Net。最后,为克服ReLU函数可能导致模型梯度不再更新的问题,该算法将Attention Gate模块的激活函数升级为可学习的SMU激活函数,提高模型鲁棒性。在NWPU VHR-10遥感数据集上,该算法相较于YOLOV7算法取得宽松指标mAP^(0.50)1.64个百分点和严格指标mAP^(0.75)9.39个百分点的性能提升。相较于目前主流的七种检测算法,该算法取得较好的检测性能。