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Sample records for hhh tcp fddi

  1. Fiber distributed data interface [FDDI] technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. Fiber Distributed Data Interface [FDDI] is the American National Standard Institute's proposed standard for a 100 Mbps token-passing ring using an optical fibre medium. The FDDI standard has become a focal point for optical technology application in the LAN environment. The market place is filling with products in every category from complete systems to optical transceivers. The 1990s see FDDI as the predominant high speed LAN and backbone. The latest edition of this report is thoroughly updated and gives a complete overview of FDDI technol

  2. Analysis of FDDI synchronous traffic delays

    Science.gov (United States)

    Johnson, Marjory J.

    1988-01-01

    The Fiber Distributed Data Interface (FDDI) high-speed token-ring protocol provides support for two classes of service: synchronous, to support applications which require deterministic access to the channel, and asynchronous, to support applications which do not have such stringent response-time requirements. The purpose of this paper is to determine how to set ring parameters to support synchronous traffic most efficiently. Both theoretical results and results obtained from a simulation study are presented.

  3. What if $\\lambda_{hhh}\

    CERN Document Server

    Efrati, Aielet

    2014-01-01

    A measurement of the Higgs trilinear self coupling $\\lambda_{hhh}$ will test the Standard Model Higgs potential. But can it reveal information that cannot be learned otherwise? By analyzing several simple extensions of the Standard Model scalar sector we show that this measurement might give a first hint for New Physics modifying the electroweak symmetry breaking. Combining the measurements of $\\lambda_{hhh}$ and $\\lambda_{hVV}$ ($V=W,Z$) is particularly powerful in distinguishing between various models of New Physics and in providing unique information on these models.

  4. Long-Haul TCP vs. Cascaded TCP

    OpenAIRE

    Feng, Wu-chun

    2006-01-01

    In this work, we investigate the bandwidth and transfer time of long-haul TCP versus cascaded TCP [5]. First, we discuss the models for TCP throughput. For TCP flows in support of bulk data transfer (i.e., long-lived TCP flows), the TCP throughput models have been derived [2, 3]. These models rely on the congestion-avoidance algorithm of TCP. Though these models cannot be applied with short-lived TCP connections, our interest relative to logistical networking is in longer-li...

  5. TCP HolyWood

    OpenAIRE

    Oscar Núñez Mori

    2005-01-01

    We introduce a new end-to-end, sender side Transport Control Protocol called TCP HolyWood or in short TCP-HW. In a simulated wired environment, TCP HolyWood outperforms in average throughput, three of the more important TCP protocols ever made, we are talking about TCP Reno, TCP Westwood, and TCP Vegas; and in average jitter to TCP Reno and TCP Vegas too. In addition, according to Jain’s index, our proposal is as fair as TCP Reno, the Standard. Apresentamos um novo Protocolo de Controle de...

  6. 40 CFR Appendix: Table 1 to... - List of Hazardous Air Pollutants (HAP) for Subpart HHH

    Science.gov (United States)

    2010-07-01

    ...) for Subpart HHH Table Appendix: Table 1 to Subpart HHH of Part 63 Protection of Environment... Natural Gas Transmission and Storage Facilities Pt. 63, Subpt. HHH, Table 1 Appendix: Table 1 to Subpart HHH of Part 63—List of Hazardous Air Pollutants (HAP) for Subpart HHH CAS Number a Chemical name...

  7. hhh Coupling in SUSY models after LHC run I

    CERN Document Server

    Wu, Lei; Yuan, Chien-Peng; Zhang, Mengchao

    2015-01-01

    We examine the Higgs triple coupling in MSSM and NMSSM under current constraints, which include the LHC measurements, Higgs data, B physics, electroweak precision observables, relic density and so on. The ratio $\\lambda^{\\rm MSSM}_{hhh}/\\lambda^{\\rm SM}_{hhh}$ is above 0.97, due to the highly constrained parameter space. While the ratio $\\lambda^{\\rm NMSSM}_{hhh}/\\lambda^{\\rm SM}_{hhh}$ can reach 0.1 under current constraints. The precise measurement in future collider will give a tighter constraint to the Higgs triple coupling in MSSM and NMSSM.

  8. Fairness of channel access for non-time-critical traffic using the FDDI token ring protocol

    Science.gov (United States)

    Johnson, M. J.

    1986-01-01

    The Fiber Distributed Data Interface (FDDI) is an ANSI draft proposed standard for a 100 megabit per second fiber optic token ring. FDDI supports two types of traffic, synchronous and asynchronous. Synchronous traffic is time critical traffic; stations are assigned guaranteed bandwidth to support their synchronous needs. Asynchronous traffic is lower priority and is sent only if time permits. It is proved analytically that the FDDI access protocol provides all stations on the ring with equal access to the channel to transmit asynchronous frames, regardless of the relative sizes of synchronous bandwidth allocations for individual stations. Analytic results are supported with data from simulation runs.

  9. An FDDI-based solution for the Systems Management Department Computer Laboratory Network

    OpenAIRE

    Chavez, Carlos M.

    1996-01-01

    FDDI is one of the latest evolutions in shared-media technology. Original intended as a high-speed backbone tor interconnecting networks, it has become a viable alternative tor organizations that seek better response time and bandwidth capacity from their local area networks (LANs). However, this fiber- based standard is an expensive departure from the more similar, and perhaps more mature, IEEE 802 token-ring and Ethernet standards. Thus, developing an FDDI- based network may present conside...

  10. Wireless optical communication for FDDI, fast Ethernet, and ATM connectivity

    Science.gov (United States)

    Medved, David B.; Azancot, Yossi

    1995-09-01

    The bandwidth limitations of spread spectrum RF technology are easily removed by use of optical carriers. A variety of wireless connectivity system applications have been achieved using IR LED (not laser) at data rates up to 125 Mbps and with low frequency corners below 100 Kbps. By use of the UWINTM principle it is possible to achieve wireless communications which are protocol independent. Thus, an urgent installation which must serve today as an Ethernet or Token Ring wireless connection in the future can be used at FDDI, Fast Ethernet, 100 VG Anylan or ATM without any modification to the original installation. In this paper we describe three separate applications of this principle where there are significant trade-offs between range and angular coverage.

  11. Transmitting time-dependent multimedia data in FDDI networks

    Science.gov (United States)

    Lim, Cheng-Chew; Yao, L.; Zhao, Wei

    1993-01-01

    Timely delivery of multimedia data is one of the key requirements in a distributed multimedia system. In a token ring network, this can be achieved by a proper control of channel access. FDDI uses a timed token MAC protocol to control the token rotation time. During network initialization, a protocol parameter called target token rotation time (TTRT) is determined. Its value indicates the expected token rotation time. Each node is assigned a fraction of the TTRT, known as synchronous bandwidth, for transmitting its synchronous messages which may be deadline constrained. In this paper, we study methods used for setting the protocol parameters such as TTRT and synchronous bandwidth. The goal is to satisfy the message deadlines. In particular, we discuss the use of the normalized proportional scheme for allocating the synchronous bandwidth. We derive a condition on the utilization factor for ensuring timely delivery of all synchronous messages, and show that 33% utilization is the tight lower bound, regardless of the number of nodes, message lengths, periods, etc. Based on this scheme, we address proper selection of TTRT and trade-off between buffer size and the capability of meeting message deadlines.

  12. TCP Pacing Developed

    Science.gov (United States)

    Ivancic, William D.

    2002-01-01

    Transmission control protocol (TCP) was conceived and designed to run over a variety of communication links, including wireless and high-bandwidth links. However, with recent technological advances in satellite and fiber-optic networks, researchers are reevaluating the flexibility of TCP. The TCP pacing and packet pair probing implementation may help overcome two of the major obstacles identified for efficient bandwidth utilization over communication links with large delay-bandwidth products.

  13. 40 CFR Table 2 to Subpart Hhh of... - Toxic Equivalency Factors

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Toxic Equivalency Factors 2 Table 2 to Subpart HHH of Part 62 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS..., Subpt. HHH, Table 2 Table 2 to Subpart HHH of Part 62—Toxic Equivalency Factors Dioxin/furan...

  14. Tests of Higgs boson compositeness through the HHH form factor

    CERN Document Server

    Gounaris, G J

    2015-01-01

    We show how the $q^2$-dependence of the triple Higgs boson HHH form factor can reveal the presence of various types of new physics contributions, like new particles coupled to the Higgs boson or Higgs boson constituents, without directly observing them. We compare the effect of such new contributions to the one of higher order SM corrections to the point-like HHH coupling, due to triangle, 4-leg and s.e. diagrams. We establish simple analytic expressions describing accurately at high energy these SM corrections, as well as the examples of new physics contributions.

  15. Surface Acoustic Wave (SAW) Technology For Clock Recovery In The Fiber Distributed Data Interface (FDDI)

    Science.gov (United States)

    Slawson, Michael R.

    1987-01-01

    This paper describes the use of Surface Acoustic Wave (SAW) technology for clock recovery, and the performance of this technology in the Fiber Distributed Data Interface (FDDI) draft standard. FDDI, because it operates at 125 MBd over the fiber optic media, requires tight control of the jitter accumulated in each point-to-point fiber link. The clock recovery function must be able to recover the clock and correctly sample the bit stream, given a relatively narrow "eye opening" at its input. Furthermore, the clock must be maintained during the FDDI "line states," which can have a very low transition density. This paper will first describe the particular implementation of SAW technology used for clock recovery, the SAW filter, and will define it purpose within the clock recovery function. Then, the jitter characteristics of the FDDI signal at the input to clock recovery, as well as the performance of the SAW-based clock recovery function under these input conditions, will be discussed. Experimental results obtained using a typical, Commercially available, SAW filter-based module will be presented. The various "detuning" sources of the SAW filter, which detract from the capability of the SAW-based module to perform accurate sampling, will be discussed. The performance of the module under FDDI line state conditions, particularly Master Line State (MLS) and Quit Line State (QLS), will be analyzed. The QLS, which indicated a disabled upstream transmitter or a cable break, contains no transitions and therefore no information for clock recovery. A circuit will be presented which uses the station's local oscillator and the "signal detect" function of the fiber optic receiver to derive the recovered clock in the event of QLS.

  16. 40 CFR Appendix: Table 2 to... - Applicability of 40 CFR Part 63 General Provisions to Subpart HHH

    Science.gov (United States)

    2010-07-01

    ... HHH of Part 63—Applicability of 40 CFR Part 63 General Provisions to Subpart HHH General provisions... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Applicability of 40 CFR Part 63 General Provisions to Subpart HHH Table Appendix: Table 2 to Subpart HHH of Part 63 Protection of...

  17. [Molecular genetic studies of mitochondrial ornithine transporter deficiency (HHH syndrome)].

    Science.gov (United States)

    Tsujino, S; Miyamoto, T; Kanazawa, N

    2001-11-01

    Mitochondrial ornithine transporter deficiency has been called HHH syndrome, because this disorder is characterized by three biochemical abnormalities; hyperornithinemia, hyperammonemia, and homocitrullinuria, and presents with various neurological symptoms; mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia and episodic disturbance of consciousness or coma due to hyperammonemia. We identified four mutations in the mitochondrial ornithine transporter gene (ORNT1) of Japanese patients with HHH syndrome. These include a nonsense mutation (R179X), associated with exon skipping, missense mutations (G27E, P126R), and an insertion of AAC between codons 228 and 229, leading to an insertion of amino acid Asn. Especially, R179X was detected 4 of 7 Japanese patients (8 of 14 alleles), implying that this is a common mutation in Japanese population.

  18. Using HIPPI switches to build high-performance multiple FDDI ring networks

    Science.gov (United States)

    Gilbert, Thomas A.

    1992-03-01

    It is a commonplace observation that computational power at the desktop is increasing at an exponential rate. This continues two decades after the first single chip VLSI microprocessor became commercially available and it is projected to continue for at least another decade. As a direct consequence, several observations can be made about the revolutionary impacts occurring in data networking: (1) Inexpensive computer power has made it economically feasible to distribute immense computational capacity to the desktop. (2) Distribution has created a demand for sophisticated networks to enable resource sharing among work groups. (3) Placing compute capacity at the point of consumption has removed the communication barrier from the `man/machine' interface. Virtually every user of computer systems is presented with increasingly rich visual paradigms. Current graphical user interfaces are designed to take advantage of bit mapped color displays that have spatial resolutions of 1024 pixels X 1280 pixels and 8 to 24 bits per pixel of color resolution. (4) Standards have been defined and systems are being built to extend the visual paradigm over the networks that interconnect information workers. (5) As a result of the exponential increase in computing capacity available for constant dollars, one would expect the demand networking capacity to increase accordingly. However, as a consequence of observation (4), the rate of increase is far greater. One of the narrow effects of the above has been to accelerate the demand for high performance networking solutions to support the burgeoning users of PCs and workstations. Fiber distributed data interface (FDDI) standard based bridges and routers have received rapid acceptance to provide backbone connections among Ethernet segments. It is not uncommon for an organization to have dozens of Ethernets within a single establishment. The cost of FDDI compatible interface boards for workstations and PCs is declining rapidly. This year the

  19. TCP/IP Security%TCP/IP协议安全

    Institute of Scientific and Technical Information of China (English)

    张少中; 唐毅谦; 赵悦; 聂铁铸; 刘丽华

    2000-01-01

    TCP/IP协议是Internet上网络互连的基础,TCP/IP 协议的安全直接关系到网络和系统的安全.本文通过分析TCP/IP的工作机制,讨论了网络入侵的基本途径,并阐述了一些改进和提高TCP/IP协议安全性的方法.

  20. Energy Efficient TCP

    NARCIS (Netherlands)

    Donckers, L.; Smit, G.J.M.; Smit, L.T.

    2002-01-01

    This paper describes the design of an energy-efficient transport protocol for mobile wireless communication. First we describe the metrics used to measure the energy efficiency of transport protocols. We identify several problem areas that prevent TCP/IP from reaching high levels of energy efficienc

  1. 40 CFR Appendix A to Subpart Hhh... - Exempted Aquifers in New Mexico

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Exempted Aquifers in New Mexico A Appendix A to Subpart HHH of Part 147 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Appendix A to Subpart HHH of Part 147—Exempted Aquifers in New Mexico The areas described by a...

  2. 40 CFR Table 1 to Subpart Hhh of... - Emission Limits for Small Rural, Small, Medium, and Large HMIWI

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission Limits for Small Rural, Small, Medium, and Large HMIWI 1 Table 1 to Subpart HHH of Part 62 Protection of Environment ENVIRONMENTAL... Incinerators Constructed on or Before June 20, 1996 Pt. 62, Subpt. HHH, Table 1 Table 1 to Subpart HHH of...

  3. Performance Improvement of TCP by TCP Reno and SACK Acknowledgement

    Directory of Open Access Journals (Sweden)

    Mrs. Reena Rai

    2012-03-01

    Full Text Available Transmission Control Protocol (TCP is the dominating end-to-end transport layer protocol which provides secure and reliable data transfer together with some other protocols. In this review paper, we contend that existing approaches to improve TCP performance over mobile ad-hoc networks have focused only on a subset of the factors affecting TCP performance by TCP Reno, SACK and Vegas. Effective resource utilization, such as bandwidth utilization, retransmission rate and window size, is compared. for evaluate these TCP congestion control algorithms from many aspects are present and We also concern fair resource allocation from two main categories, one is fairness between different delay links, and the other is competition between different TCP congestion control algorithms

  4. TCP-ADaLR: TCP with adaptive delay and loss response for broadband GEO satellite networks

    OpenAIRE

    Omueti, Modupe Omogbohun

    2007-01-01

    Transmission Control Protocol (TCP) performance degrades in broadband geostationary satellite networks due to long propagation delays and high bit error rates. In this thesis, we propose TCP with algorithm modifications for adaptive delay and loss response (TCP-ADaLR) to improve TCP performance. TCP-ADaLR incorporates delayed acknowledgement mechanism recommended for Internet hosts. We evaluate and compare the performance of TCP-ADaLR, TCP SACK, and TCP NewReno, with and without delayed ackno...

  5. High-Speed TCP Testing

    Science.gov (United States)

    Brooks, David E.; Gassman, Holly; Beering, Dave R.; Welch, Arun; Hoder, Douglas J.; Ivancic, William D.

    1999-01-01

    Transmission Control Protocol (TCP) is the underlying protocol used within the Internet for reliable information transfer. As such, there is great interest to have all implementations of TCP efficiently interoperate. This is particularly important for links exhibiting long bandwidth-delay products. The tools exist to perform TCP analysis at low rates and low delays. However, for extremely high-rate and lone-delay links such as 622 Mbps over geosynchronous satellites, new tools and testing techniques are required. This paper describes the tools and techniques used to analyze and debug various TCP implementations over high-speed, long-delay links.

  6. Abnormal urinary excretion of polyamines in HHH syndrome (hyperornithinemia associated with hyperammonemia and homocitrullinuria).

    Science.gov (United States)

    Shimizu, H; Maekawa, K; Eto, Y

    1990-01-01

    The HHH syndrome (hyperornithinemia associated with hyperammonemia and homocitrullinuria) is characterized by a very rare genetic defect of ornithine transport in mitochondrial membrane. We first demonstrated that a patient with HHH syndrome excreted about 6 times higher amount of polyamines in urine than the control when supplemented with high protein diets and ornithine loading. Each urinary polyamine fraction measured by HPLC method in HHH syndrome appears to be increased, as compared with those of the control. These data suggest that increased urinary excretion of polyamines in this syndrome is closely related to overflowing of plasma polyamine due to an ornithine transport defect in the mitochondrial membrane.

  7. TCP/IP foundations

    CERN Document Server

    Blank, Andrew G

    2006-01-01

    The world of IT is always evolving, but in every area there are stable, core concepts that anyone just setting out needed to know last year, needs to know this year, and will still need to know next year. The purpose of the Foundations series is to identify these concepts and present them in a way that gives you the strongest possible starting point, no matter what your endeavor. TCP/IP Foundations provides essential knowledge about the two protocols that form the basis for the Internet, as well as many other networks. What you learn here will benefit you in the short term, as you acquire and

  8. TCP-Rab:a receiver advertisement based TCP protocol

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    With the evolution of network technologies,the deficiencies of TCP protocol are becoming more and more distinct. The new TCP implementation,called Receiver Advertisement Based TCP(TCP-Rab)proposed here to eliminate these deficiencies,adopts two basic mechanisms:(1)Bandwidth Estimation and(2)Immediate Recovery. Bandwidth estimation is carried out at the receiver,and the result is sent back to the sender via the acknowledgments. Immediate Recovery guarantees high performance even in lossy link. Rab can distinguish the reason for packet loss,and thus adopt appropriate recovery strategy. For loss by network congestion,it will back off its congestion window,and for loss by link errors,it will recover the congestion window immediately. Simulations indicated that Rah has superiority over other TCP implementations.

  9. TCP-Rab: a receiver advertisement based TCP protocol

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    With the evolution of network technologies, the deficiencies of TCP protocol are becoming more and more distinct. The new TCP implementation, called Receiver Advertisement Based TCP (TCP-Rab) proposed here to eliminate these deficiencies, adopts two basic mechanisms: (1) Bandwidth Estimation and (2) Immediate Recovery. Bandwidth estimation is carried out at the receiver, and the result is sent back to the sender via the acknowledgments. Immediate Recovery guarantees high performance even in lossy link. Rab can distinguish the reason for packet loss, and thus adopt appropriate recovery strategy. For loss by network congestion, it will back off its congestion window, and for loss by link errors, it will recover the congestion window immediately. Simulations indicated that Rab has superiority over other TCP implementations.

  10. Estimating Bottleneck Bandwidth using TCP

    Science.gov (United States)

    Allman, Mark

    1998-01-01

    Various issues associated with estimating bottleneck bandwidth using TCP are presented in viewgraph form. Specific topics include: 1) Why TCP is wanted to estimate the bottleneck bandwidth; 2) Setting ssthresh to an appropriate value to reduce loss; 3) Possible packet-pair solutions; and 4) Preliminary results: ACTS and the Internet.

  11. Known TCP Implementation Problems

    Science.gov (United States)

    Paxson, Vern (Editor); Allman, Mark; Dawson, Scott; Fenner, William; Griner, Jim; Heavens, Ian; Lahey, K.; Semke, J.; Volz, B.

    1999-01-01

    This memo catalogs a number of known TCP implementation problems. The goal in doing so is to improve conditions in the existing Internet by enhancing the quality of current TCP/IP implementations. It is hoped that both performance and correctness issues can be resolved by making implementors aware of the problems and their solutions. In the long term, it is hoped that this will provide a reduction in unnecessary traffic on the network, the rate of connection failures due to protocol errors, and load on network servers due to time spent processing both unsuccessful connections and retransmitted data. This will help to ensure the stability of the global Internet. Each problem is defined as follows: Name of Problem The name associated with the problem. In this memo, the name is given as a subsection heading. Classification one or more problem categories for which the problem is classified: "congestion control", "performance", "reliability", "resource management". Description A definition of the problem, succinct but including necessary background material. Significance A brief summary of the sorts of environments for which the problem is significant.

  12. Improving Throughput For TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    LIU Gang; ZHANG De-yun; LIU Jing; DING Hui-ning

    2004-01-01

    To slove the problem that the implementation of Transmission Control Protocol (TCP) Vegas does not consider the impact of TCP's segment size on Round-Trip Time (RTT) while calculating RTT and the smallest RTT (base_rtt), this paper proposes a modified congestion control mechanism for TCP Vegas. It first groups segments on the basis of segments size and updates base_rtt based on groups. In congestion avoidance phase, TCP Vegas changes its window size according to the measured RTT of the segment corresponding to the latest received ACK and the base_rtt retrieved from the group that the segment belongs to. Simulations illustrate that the enhanced TCP Vegas can achieve higher throughput up to 40 percent.

  13. Diagnosis and high incidence of hyperornithinemia-hyperammonemia-homocitrullinemia (HHH) syndrome in northern Saskatchewan.

    Science.gov (United States)

    Sokoro, AbdulRazaq A H; Lepage, Joyce; Antonishyn, Nick; McDonald, Ryan; Rockman-Greenberg, Cheryl; Irvine, James; Lehotay, Denis C

    2010-12-01

    Mutations in the SLC25A15 gene, encoding the human inner mitochondrial membrane ornithine transporter, are thought to be responsible for hyperornithinemia-hyperammonemia-homocitrullinemia (HHH) syndrome, a rare autosomal recessive condition. HHH syndrome has been detected in several small, isolated communities in northern Saskatchewan (SK). To determine the incidence of HHH syndrome in these communities, a PCR method was set up to detect F188Δ, the common French-Canadian mutation. Neonatal blood spots collected from all newborns from the high risk area were genotyped for the F188Δ mutation for seven consecutive years. Using DNA analysis, we estimated that the heterozygote frequency for the mutant allele for HHH syndrome to be about 1 in 19 individuals, predicting one affected child with HHH syndrome for approximately every 1,500 individuals (1 in 1,550 live births; 1 child every 12 years) in this isolated population. The frequency for the mutant allele for HHH syndrome in this isolated community is probably the highest in the world for this rare disorder. We determined that ornithine levels, by tandem mass spectrometry, were not abnormal in newborns with F188Δ mutation, carriers and normals. Ornithine rises to abnormally high levels at some time after birth well past the time that the newborn screening blood spot is collected. The timing or the reasons for the delayed rise of ornithine in affected children with HHH syndrome have not been determined. Newborn screening for HHH Syndrome in this high risk population is only possible by detection of the mutant allele using DNA analysis.

  14. Optimizing TCP Performance over UMTS with Split TCP Proxy

    DEFF Research Database (Denmark)

    Hu, Liang; Dittmann, Lars

    2009-01-01

    Abstract: The TCP performance over UMTS network is challenged by the large delay bandwidth product. Large delay bandwidth product is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer which are used to cope with radio transmission errors....... To cope with large delay bandwidth product, we propose a novel concept of split TCP proxy which is placed at GGSN between UNITS network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products which can...

  15. Introduction à TCP/IP

    OpenAIRE

    Archimbaud, Jean-Luc

    1993-01-01

    • Ce qu'il faut savoir sur les réseaux • Ce qu'il faut savoir sur Ethernet • Généralités sur TCP/IP • IP et consort • TCP et consort • Le routage • Interconnexion de réseaux Ethernet et IP • Nommage • Exemples d'applications • Enchaînement des opérations • Daemons et commandes Unix • Glossaire; Engineering school; Cours d'introduction à TCP/IP

  16. Modelica-based TCP simulation

    Science.gov (United States)

    Velieva, T. R.; Eferina, E. G.; Korolkova, A. V.; Kulyabov, D. S.; Sevastianov, L. A.

    2017-01-01

    For the study and verification of our mathematical model of telecommunication systems a discrete simulation model and a continuous analytical model were developed. However, for various reasons, these implementations are not entirely satisfactory. It is necessary to develop a more adequate simulation model, possibly using a different modeling paradigm. In order to modeling of the TCP source it is proposed to use a hybrid (continuous-discrete) approach. For computer implementation of the model the physical modeling language Modelica is used. The hybrid approach allows us to take into account the transitions between different states in the continuous model of the TCP protocol. The considered approach allowed to obtain a simple simulation model of TCP source. This model has great potential for expansion. It is possible to implement different types of TCP.

  17. Fixing Two BSD TCP Bugs

    Science.gov (United States)

    Allman, Mark

    1997-01-01

    This note outlines two bugs found in the BSD 4.4 Lite TCP implementation, as well as the implications of these bugs and possible ways to correct them. The first problem encountered in this particular TCP implementation is the use of a 2 segment initial congestion window, rather than the standard 1 segment initial window. The second problem is that the receiver delays ACKs in violation of the delayed ACK rules,

  18. Experimental evaluation of TCP protocols for high-speed networks

    OpenAIRE

    Li, Yee-Ting; Leith, Douglas J.; Shorten, Robert N.

    2007-01-01

    In this paper, we present experimental results evaluating the performance of the scalable-TCP, HS-TCP, BIC-TCP, FAST-TCP, and H-TCP proposals in a series of benchmark tests. In summary, we find that both Scalable-TCP and FAST-TCP consistently exhibit substantial unfairness, even when competing flows share identical network path characteristics. Scalable-TCP, HS-TCP, FAST-TCP, and BIC-TCP all exhibit much greater RTT unfairness than does standard TCP, to the extent that long RTT flows ma...

  19. FDDI information management system for centralizing interactive, computerized multimedia clinical experiences in pediatric rheumatology/Immunology.

    Science.gov (United States)

    Rouhani, R; Cronenberger, H; Stein, L; Hannum, W; Reed, A M; Wilhelm, C; Hsiao, H

    1995-01-01

    This paper describes the design, authoring, and development of interactive, computerized, multimedia clinical simulations in pediatric rheumatology/immunology and related musculoskeletal diseases, the development and implementation of a high speed information management system for their centralized storage and distribution, and analytical methods for evaluating the total system's educational impact on medical students and pediatric residents. An FDDI fiber optic network with client/server/host architecture is the core. The server houses digitized audio, still-image video clips and text files. A host station houses the DB2/2 database containing case-associated labels and information. Cases can be accessed from any workstation via a customized interface in AVA/2 written specifically for this application. OS/2 Presentation Manager controls, written in C, are incorporated into the interface. This interface allows SQL searches and retrievals of cases and case materials. In addition to providing user-directed clinical experiences, this centralized information management system provides designated faculty with the ability to add audio notes and visual pointers to image files. Users may browse through case materials, mark selected ones and download them for utilization in lectures or for editing and converting into 35mm slides.

  20. Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development

    OpenAIRE

    Jose Antonio Aguilar Martinez; Neelima Roy Sinha

    2013-01-01

    TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found...

  1. Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (HHH) presenting with acute fulminant hepatic failure.

    Science.gov (United States)

    Mhanni, A A; Chan, A; Collison, M; Seifert, B; Lehotay, D C; Sokoro, Ah; Huynh, H Q; Greenberg, C R

    2008-03-01

    We report on two Aboriginal patients with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome. Both presented with acute hepatic failure with severe hypertransaminasemia and coagulopathy, prompting evaluation for emergent liver transplantation. The diagnosis of HHH syndrome was based on the presence of typical metabolic abnormalities. A protein-restricted diet and L-arginine or L-citrulline supplementation were immediately started, with rapid normalization of liver function test results and other biochemical abnormalities. Molecular analysis of the SLC25A15 gene showed that the two patients were homozygous for the common French Canadian mutation (F188Delta). The diagnosis of HHH syndrome should be considered in patients with unexplained fulminant hepatic failure. There does not appear to be a genotype-phenotype correlation for this presentation, inasmuch as the only other reported patient presenting with this picture had two different point mutations. Early identification and prompt treatment of these patients is crucial to avoid liver transplantation and can be life saving.

  2. HHH syndrome (hyperornithinaemia, hyperammonaemia, homocitrullinuria), with fulminant hepatitis-like presentation.

    Science.gov (United States)

    Fecarotta, S; Parenti, G; Vajro, P; Zuppaldi, A; Della Casa, R; Carbone, M T; Correra, A; Torre, G; Riva, S; Dionisi-Vici, C; Santorelli, F M; Andria, G

    2006-02-01

    We report a 3-year-old Italian patient with the hyperornithinaemia, hyperammonaemia, homocitrullinuria (HHH) syndrome who presented with neurological deterioration after an intercurrent infection. Hyperammonaemia, coagulopathy and moderate hypertransaminasaemia were detected on hospital admission. Severe hepatocellular necrosis with hypertransaminasaemia (aspartate aminotransferase 20,000 UI/L, alanine aminotransferase 18,400 UI/L) and coagulopathy (PT HHH syndrome was based on the presence of the typical metabolic abnormalities. Molecular analysis of the SLC25A15 gene showed that the patient was heterozygous for two novel mutations (G113C and M273K). The diagnosis of HHH syndrome should be considered in patients with fulminant hepatitis-like presentations. Early identification and treatment of these patients can be life-saving and can avoid liver transplantation.

  3. 基于TCP Reno和TCP Vegas拥塞控制性能研究%Research of congestion control performance based on TCP Reno and TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    刘国柱; 高文娟

    2011-01-01

    介绍了传输控制协议(TCP)的拥塞控制技术,对两种典型的TCP拥塞控制算法TCP Reno和TCP Vegas进行了详尽的分析,对其性能进行了比较.同时对TCP Reno和TCP Vegas在混存网络环境下的性能进行分析,并针对TCP Vegas中的α和β参数进行修改,提出了Vegas.A+算法使它们能并存于网络中.在NS2仿真环境下对改进的控制算法进行了仿真,仿真结果表明了改进算法的有效性.%The TCP (Transmission Control Protocol) congestion control techniques, and a detailed analysis of TCP Reno and TCP Vegas which are two typical TCP congestion control algorithms are mainly focused on. The performance of the TCP Reno and TCP Vegas in the mixed network environment is also analyzed, and not only the parameters α and β of the TCP Vegas are modified properly, but also an algorithm called Vegas-A+ is proposed, so that they can co-exist in the network. It is simulated by NS2, and proved the validity of the improved method.

  4. Performance of TCP variants over LTE network

    Science.gov (United States)

    Nor, Shahrudin Awang; Maulana, Ade Novia

    2016-08-01

    One of the implementation of a wireless network is based on mobile broadband technology Long Term Evolution (LTE). LTE offers a variety of advantages, especially in terms of access speed, capacity, architectural simplicity and ease of implementation, as well as the breadth of choice of the type of user equipment (UE) that can establish the access. The majority of the Internet connections in the world happen using the TCP (Transmission Control Protocol) due to the TCP's reliability in transmitting packets in the network. TCP reliability lies in the ability to control the congestion. TCP was originally designed for wired media, but LTE connected through a wireless medium that is not stable in comparison to wired media. A wide variety of TCP has been made to produce a better performance than its predecessor. In this study, we simulate the performance provided by the TCP NewReno and TCP Vegas based on simulation using network simulator version 2 (ns2). The TCP performance is analyzed in terms of throughput, packet loss and end-to-end delay. In comparing the performance of TCP NewReno and TCP Vegas, the simulation result shows that the throughput of TCP NewReno is slightly higher than TCP Vegas, while TCP Vegas gives significantly better end-to-end delay and packet loss. The analysis of throughput, packet loss and end-to-end delay are made to evaluate the simulation.

  5. Internetworking with TCP/IP

    CERN Document Server

    Comer, Douglas E

    2014-01-01

    An internationally best-selling, conceptual introduction to the TCP/IP protocols and Internetworking, this book interweaves a clear discussion of fundamentals and scientific principles with details and examples drawn from the latest technologies. Leading author Douglas Comer covers layering and packet formats for all the Internet protocols, includingTCP, IPv4, IPv6, DHCP, and DNS. In addition, the text explains new trends in Internet systems, including packet classification, Software Defined Networking (SDN), and mesh protocols used in The Internet of Things. The text is appropriate for individuals interested in learning more about TCP/IP protocols, Internet architecture, and current networking technologies, as well as engineers who build network systems. It is suitable for junior to graduate-level courses in Computer Networks, Data Networks, Network Protocols, and Internetworking.

  6. Optical Switching Impact on TCP Throughput Limited by TCP Buffers

    NARCIS (Netherlands)

    Moura, Giovane C.M.; Fioreze, Tiago; Boer, de Pieter-Tjerk; Pras, Aiko; Nunzi, G.; Scoglio, C.; Li, X.

    2009-01-01

    In this paper, we observe the performance of TCP throughput when self-management is employed to automatically move flows from the IP level to established connections at the optical level. This move can result in many packets arriving out of order at the receiver and even being discarded, since some

  7. Analysis of the role of Arabidopsis class I TCP genes AtTCP7, AtTCP8, AtTCP22, and AtTCP23 in leaf development.

    Science.gov (United States)

    Aguilar-Martínez, José A; Sinha, Neelima

    2013-01-01

    TCP family of plant-specific transcription factors regulates plant form through control of cell proliferation and differentiation. This gene family is comprised of two groups, class I and class II. While the role of class II TCP genes in plant development is well known, data about the function of some class I TCP genes is lacking. We studied a group of phylogenetically related class I TCP genes: AtTCP7, AtTCP8, AtTCP22, and AtTCP23. The similar expression pattern in young growing leaves found for this group suggests similarity in gene function. Gene redundancy is characteristic in this group, as also seen in the class II TCP genes. We generated a pentuple mutant tcp8 tcp15 tcp21 tcp22 tcp23 and show that loss of function of these genes results in changes in leaf developmental traits. We also determined that these factors are able to mutually interact in a yeast two-hybrid assay and regulate the expression of KNOX1 genes. To circumvent the issue of genetic redundancy, dominant negative forms with SRDX repressor domain were used. Analysis of transgenic plants expressing AtTCP7-SRDX and AtTCP23-SRDX indicate a role of these factors in the control of cell proliferation.

  8. Ultrastructural changes in fibroblast mitochondria of a patient with HHH-syndrome.

    Science.gov (United States)

    Metoki, K; Hommes, F A; Dyken, P; Kelloes, C; Trefz, J

    1984-01-01

    Electron micrographs of fibroblasts of an HHH-syndrome patient showed abnormal structures, similar, but not identical, to those observed in the liver of such patients. It is suggested that incorporation of a mutated protein into the inner mitochondrial membrane gives rise to a rearrangement of that membrane, resulting in unusual structures.

  9. The HhH domain of the human DNA repair protein XPF forms stable homodimers.

    Science.gov (United States)

    Das, Devashish; Tripsianes, Konstantinos; Jaspers, Nicolaas G J; Hoeijmakers, Jan H J; Kaptein, Robert; Boelens, Rolf; Folkers, Gert E

    2008-03-01

    The human XPF-ERCC1 protein complex plays an essential role in nucleotide excision repair by catalysing positioned nicking of a DNA strand at the 5' side of the damage. We have recently solved the structure of the heterodimeric complex of the C-terminal domains of XPF and ERCC1 (Tripsianes et al., Structure 2005;13:1849-1858). We found that this complex comprises a pseudo twofold symmetry axis and that the helix-hairpin-helix motif of ERCC1 is required for DNA binding, whereas the corresponding domain of XPF is functioning as a scaffold for complex formation with ERCC1. Despite the functional importance of heterodimerization, the C-terminal domain of XPF can also form homodimers in vitro. We here compare the stabilities of homodimeric and heterodimeric complexes of the C-terminal domains of XPF and ERCC1. The higher stability of the XPF HhH complexes under various experimental conditions, determined using CD and NMR spectroscopy and mass spectrometry, is well explained by the structural differences that exist between the HhH domains of the two complexes. The XPF HhH homodimer has a larger interaction interface, aromatic stacking interactions, and additional hydrogen bond contacts as compared to the XPF/ERCC1 HhH complex, which accounts for its higher stability.

  10. A novel mutation, P126R, in a Japanese patient with HHH syndrome.

    Science.gov (United States)

    Miyamoto, Takeshi; Kanazawa, Naomi; Hayakawa, Chiemi; Tsujino, Seiichi

    2002-01-01

    Mitochondrial ornithine transporter deficiency, or HHH syndrome, is a metabolic disorder resulting in various neurologic symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma caused by hyperammonemia. Several mutations have been reported in the ORNT1 gene encoding mitochondrial ornithine transporter of patients with this disorder. In this article, we report a new patient, a male 15 years of age, who had typical clinical features of HHH syndrome. Because the patient did not have any of the three mutations previously described in other Japanese patients with HHH syndrome, and the only material available from the patient was peripheral leukocytes, we established a genomic polymerase chain reaction method using intronic primers to amplify every exon of the ORNT1 gene, and we directly sequenced the polymerase chain reaction products. Using this method, we documented a novel mutation in this patient, P126R, and demonstrated that HHH syndrome is genetically heterogeneous, even in the Japanese population.

  11. A TCP-Over-UDP Test Harness

    Energy Technology Data Exchange (ETDEWEB)

    Dunigan, TH

    2002-10-31

    This report describes an implementation of a TCP-like protocol that runs over UDP. This TCP-like implementation, which does not require kernel modifications, provides a test harness for evaluating variations of the TCP transport protocol over the Internet. The test harness provides a tunable and instrumented version of TCP that supports Reno, NewReno, and SACK/FACK. The test harness can also be used to characterize the TCP-performance of a network path. Several case studies illustrate how one can tune the transport protocol to improve performance.

  12. TCP Performance Enhancement for UMTS Access Network

    DEFF Research Database (Denmark)

    Hu, Liang

    2008-01-01

    We aim at optimize the TCP performance over UMTS access network challenged by the large delay bandwidth product that is mainly caused by the latency from the link layer ARQ retransmissions and diversity technique at physical layer. We propose to place a split TCP proxy at GGSN nodes which...... is between UMTS access network and Internet. The split proxy divides the bandwidth delay product into two parts, resulting in two TCP connections with smaller bandwidth delay products. Simulation results show, the split TCP proxy can significantly improve the TCP performance under high bit rate DCH channel...... scenario (e.g.256 kbps). Besides, the split TCP proxy brings more performance gain for downloading large files than downloading small ones. Finally, an aggressive initial TCP congestion window size at proxy can brings even more performance gain for radio links with high data rates DCH channels with large...

  13. AN ENHANCEMENT SCHEME OF TCP PROTOCOL IN MOBILE AD HOC NETWORKS: MME-TCP

    Institute of Scientific and Technical Information of China (English)

    Kai Caihong; Yu Nenghai; Chen Yuzhong

    2007-01-01

    Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper,a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP)designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore, these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs.

  14. Clinical and functional characterization of a human ORNT1 mutation (T32R) in the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome.

    Science.gov (United States)

    Camacho, José A; Mardach, Rebecca; Rioseco-Camacho, Natalia; Ruiz-Pesini, Eduardo; Derbeneva, Olga; Andrade, Dario; Zaldivar, Frank; Qu, Yong; Cederbaum, Stephen D

    2006-10-01

    We studied two related families (HHH013 and HHH015) with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, a disorder of the urea cycle and ornithine degradation pathway, who have the same novel ornithine transporter (ORNT1) genotype (T32R) but a variable phenotype. Both HHH015 patients are doing well in school and are clinically stable; conversely, the three affected HHH013 siblings had academic difficulties and one suffered recurrent episodes of hyperammonemia and ultimately died. Overexpression studies revealed that the product of the ORNT1-T32R allele has residual function. Ornithine transport studies in HHH015 fibroblasts, however, showed basal activity similar to fibroblasts carrying nonfunctional ORNT1 alleles. We also examined two potential modifying factors, the ORNT2 gene and the mitochondrial DNA lineage (haplogroup). Haplogroups, associated with specific diseases, are hypothesized to influence mitochondrial function. Results demonstrated that both HHH015 patients are heterozygous for an ORNT2 gain of function polymorphism and belong to haplogroup A whereas the HHH013 siblings carry the wild-type ORNT2 and are haplogroup H. These observations suggest that the ORNT1 genotype cannot predict the phenotype of HHH patients. The reason for the phenotypic variability is unknown, but factors such as redundant transporters and mitochondrial lineage may contribute to the neuropathophysiology of HHH patients.

  15. OSI and TCP/IP

    Science.gov (United States)

    Randolph, Lynwood P.

    1994-01-01

    The Open Systems Interconnection Transmission Control Protocol/Internet Protocol (OSI TCP/IP) and the Government Open Systems Interconnection Profile (GOSIP) are compared and described in terms of Federal internetworking. The organization and functions of the Federal Internetworking Requirements Panel (FIRP) are discussed and the panel's conclusions and recommendations with respect to the standards and implementation of the National Information Infrastructure (NII) are presented.

  16. On the Effective Evaluation of TCP

    Science.gov (United States)

    Allman, Mark; Falk, Aaron

    2000-01-01

    Understanding the performance of the Internet's Transmission Control Protocol (TCP) is important because it is the dominant protocol used in the Internet today. Various testing methods exist to evaluate TCP performance, however all have pitfalls an that need to be understood prior to obtaining useful results. Simulating TCP is difficult because of the wide range of variables, environments, and implementations available. Testing TCP modifications in the global Internet may not be the answer either: testing new protocols on real networks endangers other people's traffic and, if not done correctly, may also yield inaccurate or misleading results. In order for TCP research to be independently evaluated in the Internet research community there is a set of questions that researchers should try to answer. This paper attempts to list some of those questions and make recommendations as to how TCP testing can be structured to be provide useful answers.

  17. Potential performance bottleneck in Linux TCP

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wenji; Crawford, Matt; /Fermilab

    2006-12-01

    TCP is the most widely used transport protocol on the Internet today. Over the years, especially recently, due to requirements of high bandwidth transmission, various approaches have been proposed to improve TCP performance. The Linux 2.6 kernel is now preemptible. It can be interrupted mid-task, making the system more responsive and interactive. However, we have noticed that Linux kernel preemption can interact badly with the performance of the networking subsystem. In this paper we investigate the performance bottleneck in Linux TCP. We systematically describe the trip of a TCP packet from its ingress into a Linux network end system to its final delivery to the application; we study the performance bottleneck in Linux TCP through mathematical modeling and practical experiments; finally we propose and test one possible solution to resolve this performance bottleneck in Linux TCP.

  18. Conscientious metabolic monitoring on a patient with hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome undergoing anaesthesia.

    Science.gov (United States)

    Mühling, J; Dehne, M G; Fuchs, M; Sablotzki, A; Weiss, S; Spatz, J; Hempelmann, G

    2001-01-01

    Currently we know not more than 50 patients who show an interesting combination of increased plasma ornithine concentrations, postprandial hyperammonemia, and homocitrullinuria (HHH-syndrome). Since exact knowledge of this severe, although rare syndrome is important for any perioperative or intensive medical treatment concerning therapy and progression of the disease, we report a comprehensive study on a 32-year old woman with this rare multifaceted disorder who had to undergo general anaesthesia. For the first time amino acid status in plasma, urine, cerebrospinal fluid and especially polymorphonuclear leucocytes, which in the investigation showed to be valuable tool for evaluating amino acid metabolism in nucleated cells in HHH-syndrome, and further important pathophysiologic indicators of cellular and metabolic function have been conscientiously investigated and compared. The pathophysiological repercussions of our results as well as the recommendations for conscientious therapeutical management are discussed.

  19. TCP over IEEE 802.11

    Directory of Open Access Journals (Sweden)

    P. Chenna Reddy

    2009-01-01

    Full Text Available IEEE 802.11 is a widely used wireless LAN standard for medium access control. TCP is a prominent transport protocol originally designed for wired networks. TCP treats packet loss as congestion and reduces the data rate. In wireless networks packets are lost not only due to congestion but also due to various other reasons. Hence there is need for making TCP adaptable to wireless networks. Various parameters of TCP and IEEE 802.11 can be set to appropriate values to achieve optimum performance results. In this paper optimum values for various parameters of IEEE 802.11 are determined. Network simulator NS2 is used for simulation.

  20. A Simulation Study of Paced TCP

    Science.gov (United States)

    Kulik, Joanna; Coulter, Robert; Rockwell, Dennis; Partridge, Craig

    2000-01-01

    In this paper, we study the performance of paced TCP, a modified version of TCP designed especially for high delay- bandwidth networks. In typical networks, TCP optimizes its send-rate by transmitting increasingly large bursts, or windows, of packets, one burst per round-trip time, until it reaches a maximum window-size, which corresponds to the full capacity of the network. In a network with a high delay-bandwidth product, however, Transmission Control Protocol's (TCPs) maximum window-size may be larger than the queue size of the intermediate routers, and routers will begin to drop packets as soon as the windows become too large for the router queues. The TCP sender then concludes that the bottleneck capacity of the network has been reached, and it limits its send-rate accordingly. Partridge proposed paced TCP as a means of solving the problem of queueing bottlenecks. A sender using paced TCP would release packets in multiple, small bursts during a round-trip time in which ordinary TCP would release a single, large burst of packets. This approach allows the sender to increase its send-rate to the maximum window size without encountering queueing bottlenecks. This paper describes the performance of paced TCP in a simulated network and discusses implementation details that can affect the performance of paced TCP.

  1. Ciliated cultured dermal fibroblasts in a patient with hyperornithinemia, hyperammonemia and homocitrullinuria (HHH) syndrome.

    Science.gov (United States)

    Haust, M D

    1995-10-01

    Hyperornithinemia, hyperammonemia and homocitrullinuria (HHH)-syndrome is a rare autosomal recessive disorder of the urea cycle, probably caused by a defect in ornithine transport across the hepatic inner mitochondrial membrane. Single rudimentary cilia were present in approximately ten percent of post-divisional or dividing fibroblasts cultured from the skin of a patient with the HHH-syndrome, whereas no such organelles were observed in dermal fibroblasts cultured from normal controls. Since single rudimentary ("primary," "oligo," "solitary") cilia have been observed in a variety of cells in animals and men but the stimuli for their formation and their significance remain controversial, a brief report on their presence in the as yet unreported condition (HHH-syndrome) was considered of interest; hopefully, it might contribute to the ultimate unravelling of some of the unresolved problems. It is of note that unlike the author's previous findings of these unusual organelles in cells affected by a pathological process (atherosclerosis), the rudimentary cilia were observed in the present instance in dividing or postdivisional cells. The implications of these (and other) observations must await further work.

  2. TCP/IP Network Administration

    CERN Document Server

    Hunt, Craig

    2002-01-01

    This complete guide to setting up and running a TCP/IP network is essential for network administrators, and invaluable for users of home systems that access the Internet. The book starts with the fundamentals -- what protocols do and how they work, how addresses and routing are used to move data through the network, how to set up your network connection -- and then covers, in detail, everything you need to know to exchange information via the Internet. Included are discussions on advanced routing protocols (RIPv2, OSPF, and BGP) and the gated software package that implements them, a tutorial

  3. TCP Performance Enhancement Over Iridium

    Science.gov (United States)

    Torgerson, Leigh; Hutcherson, Joseph; McKelvey, James

    2007-01-01

    In support of iNET maturation, NASA-JPL has collaborated with NASA-Dryden to develop, test and demonstrate an over-the-horizon vehicle-to-ground networking capability, using Iridium as the vehicle-to-ground communications link for relaying critical vehicle telemetry. To ensure reliability concerns are met, the Space Communications Protocol Standards (SCPS) transport protocol was investigated for its performance characteristics in this environment. In particular, the SCPS-TP software performance was compared to that of the standard Transmission Control Protocol (TCP) over the Internet Protocol (IP). This paper will report on the results of this work.

  4. TCP/IP-sokettiohjelmoinnin sovelluslogiikka

    OpenAIRE

    Savolainen, Stanislav

    2014-01-01

    Insinöörityö kertoo, miten TCP-sokettien sovelluslogiikka rakentuu ja miten sitä voi käyttää ohjelmistoprojektissa. Voidaan tehdä omia verkkosovelluksia esimerkiksi web-selaimia, http-palvelimia, monipelejä, chat-ohjelmia, tiedostojakeluohjelmia ja muita sovelluksia. Työ näyttää myös sen, että verkko-ohjelmoinnin opettelun aloitusvaihe ei ole kovin vaikeaa eikä tarvitse tietää paljon tietoliikenteestä aloittaakseen yksinkertaisten omien verkko-ohjelmien teon. Kerron askel kerrallaan, mite...

  5. TCP transcription factors: architectures of plant form.

    Science.gov (United States)

    Manassero, Nora G Uberti; Viola, Ivana L; Welchen, Elina; Gonzalez, Daniel H

    2013-04-01

    After its initial definition in 1999, the TCP family of transcription factors has become the focus of a multiplicity of studies related with plant development at the cellular, organ, and tissue levels. Evidence has accumulated indicating that TCP transcription factors are the main regulators of plant form and architecture and constitute a tool through which evolution shapes plant diversity. The TCP transcription factors act in a multiplicity of pathways related with cell proliferation and hormone responses. In recent years, the molecular pathways of TCP protein action and biochemical studies on their mode of interaction with DNA have begun to shed light on their mechanism of action. However, the available information is fragmented and a unifying view of TCP protein action is lacking, as well as detailed structural studies of the TCP-DNA complex. Also important, the possible role of TCP proteins as integrators of plant developmental responses to the environment has deserved little attention. In this review, we summarize the current knowledge about the structure and functions of TCP transcription factors and analyze future perspectives for the study of the role of these proteins and their use to modify plant development.

  6. Enhancing Energy Efficient TCP by Partial Reliability

    NARCIS (Netherlands)

    Donckers, L.; Smit, G.J.M.; Smit, L.T.

    2002-01-01

    We present a study on the effects on a mobile system's energy efficiency of enhancing, with partial reliability, our energy efficient TCP variant (E/sup 2/TCP) (see Donckers, L. et al., Proc. 2nd Asian Int. Mobile Computing Conf. - AMOC2002, p.18-28, 2002). Partial reliability is beneficial for mult

  7. Performance of TCP with multiple Priority Classes

    NARCIS (Netherlands)

    Vranken, R.; Mei, van der R.D.; Kooij, R.E.; Berg, van den J.L.

    2002-01-01

    We consider the dimensioning problem for Internet access links carrying TCP traffic with two priority classes. To this end, we study the behaviour of TCP at the flow level described by a multiple-server Processor Sharing (PS) queueing model with two customer classes, where the customers represent fl

  8. FAST TCP: From Theory to Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jin, C.

    2004-11-23

    We describe a variant of TCP, called FAST, that can sustain high throughput and utilization at multi-Gbps over large distance. We present the motivation, review the background theory, summarize key features of FAST TCP, and report our first experimental results.

  9. Diagnosis of Japanese patients with HHH syndrome by molecular genetic analysis: a common mutation, R179X.

    Science.gov (United States)

    Miyamoto, T; Kanazawa, N; Kato, S; Kawakami, M; Inoue, Y; Kuhara, T; Inoue, T; Takeshita, K; Tsujino, S

    2001-01-01

    Patients with mitochondrial ornithine transporter deficiency (or HHH syndrome) present with various neurological symptoms, including mental retardation, spastic paraparesis with pyramidal signs, cerebellar ataxia, and episodic disturbance of consciousness or coma due to hyperammonemia. We previously described three novel mutations in the ORNT1 gene in Japanese patients with HHH syndrome. In this article, we report a new patient with HHH syndrome, a 52-year-old woman, who had the typical clinical features, except for an absence of mental retardation. When we screened this patient, as well as a previously described Japanese patient, for mutations in the ORNT1 gene, we found that both were homozygous for a nonsense mutation (R179X). Furthermore, reverse transcription (RT)-polymerase chain reaction (PCR) of fibroblast RNA from one patient showed exon 4 skipping, as had been observed in a previously reported patient with R179X. These results, together with the findings in our previous report, show that, in three of our five reported Japanese HHH patients (six of ten alleles), R179X is present, suggesting that this is a common mutation in Japanese patients with HHH syndrome.

  10. Mechanism of lubrication by tricresylphosphate (TCP)

    Science.gov (United States)

    Faut, O. D.; Buckley, D. H.

    1984-01-01

    The coefficient of friction was measured as a function of temperature on a pin-on-disk tribometer. Pins and disks of 440C and 52100 steels were lubricated with tricresylphosphate (TCP), 3.45 percent TCP in squalene, and pure squalene. The M-50 pins and disks were lubricated with 3.45 percent TCP in squalene and pure squalene. Experiments were conducted under limited lubrication conditions in dry ( 100 ppm H2O) air and dry ( pp H2O) nitrogen at 50 rpm (equivalent to a sliding velocity of 13 cm sec) and a constant load of 9.8 N (1 kg). Characteristic temperatures T sub r were identified for TCP on 52100 steel and for squalene on M-50 and 52100 steels, where the friction decreased because of a chemical reaction between the lubricant and the metal surface. The behavior of squalene obscured the influence of 3.45 percent TCP solute on the friction of the system. Wear volume measurements demonstrated that wear was lowest at temperatures just above T sub r. Comparing the behavior of TCP on M-50, 440C, and 52100 steels revealed that the TCP either reacted to give T sub r behavior or produced initial failure in the temperature range 223 + or - 5 C.

  11. Insights into the mutation-induced HHH syndrome from modeling human mitochondrial ornithine transporter-1.

    Directory of Open Access Journals (Sweden)

    Jing-Fang Wang

    Full Text Available Human mitochondrial ornithine transporter-1 is reported in coupling with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH syndrome, which is a rare autosomal recessive disorder. For in-depth understanding of the molecular mechanism of the disease, it is crucially important to acquire the 3D structure of human mitochondrial ornithine transporter-1. Since no such structure is available in the current protein structure database, we have developed it via computational approaches based on the recent NMR structure of human mitochondrial uncoupling protein (Berardi MJ, Chou JJ, et al. Nature 2011, 476:109-113. Subsequently, we docked the ligand L-ornithine into the computational structure to search for the favorable binding mode. It was observed that the binding interaction for the most favorable binding mode is featured by six remarkable hydrogen bonds between the receptor and ligand, and that the most favorable binding mode shared the same ligand-binding site with most of the homologous mitochondrial carriers from different organisms, implying that the ligand-binding sites are quite conservative in the mitochondrial carriers family although their sequences similarity is very low with 20% or so. Moreover, according to our structural analysis, the relationship between the disease-causing mutations of human mitochondrial ornithine transporter-1 and the HHH syndrome can be classified into the following three categories: (i the mutation occurs in the pseudo-repeat regions so as to change the region of the protein closer to the mitochondrial matrix; (ii the mutation is directly affecting the substrate binding pocket so as to reduce the substrate binding affinity; (iii the mutation is located in the structural region closer to the intermembrane space that can significantly break the salt bridge networks of the protein. These findings may provide useful insights for in-depth understanding of the molecular mechanism of the HHH syndrome and

  12. Insights into the mutation-induced HHH syndrome from modeling human mitochondrial ornithine transporter-1.

    Science.gov (United States)

    Wang, Jing-Fang; Chou, Kuo-Chen

    2012-01-01

    Human mitochondrial ornithine transporter-1 is reported in coupling with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome, which is a rare autosomal recessive disorder. For in-depth understanding of the molecular mechanism of the disease, it is crucially important to acquire the 3D structure of human mitochondrial ornithine transporter-1. Since no such structure is available in the current protein structure database, we have developed it via computational approaches based on the recent NMR structure of human mitochondrial uncoupling protein (Berardi MJ, Chou JJ, et al. Nature 2011, 476:109-113). Subsequently, we docked the ligand L-ornithine into the computational structure to search for the favorable binding mode. It was observed that the binding interaction for the most favorable binding mode is featured by six remarkable hydrogen bonds between the receptor and ligand, and that the most favorable binding mode shared the same ligand-binding site with most of the homologous mitochondrial carriers from different organisms, implying that the ligand-binding sites are quite conservative in the mitochondrial carriers family although their sequences similarity is very low with 20% or so. Moreover, according to our structural analysis, the relationship between the disease-causing mutations of human mitochondrial ornithine transporter-1 and the HHH syndrome can be classified into the following three categories: (i) the mutation occurs in the pseudo-repeat regions so as to change the region of the protein closer to the mitochondrial matrix; (ii) the mutation is directly affecting the substrate binding pocket so as to reduce the substrate binding affinity; (iii) the mutation is located in the structural region closer to the intermembrane space that can significantly break the salt bridge networks of the protein. These findings may provide useful insights for in-depth understanding of the molecular mechanism of the HHH syndrome and developing effective

  13. Studies on a case of HHH-syndrome (hyperammonemia, hyperornithinemia, homocitrullinuria).

    Science.gov (United States)

    Hommes, F A; Roesel, R A; Metoki, K; Hartlage, P L; Dyken, P R

    1986-02-01

    A patient with the hyperornithinemia, hyperammonemia, homocitrullinuria syndrome is described. This patient represents the 12th documented case of this rare, presumably autosomal recessive condition. Increased levels of ammonia, ornithine and homocitrulline were demonstrated in blood and cerebrospinal fluid. The blood ammonia concentration could be lowered by supplementation of the diet with low doses of arginine. High doses of arginine precipitated seizures, although plasma levels of arginine and ornithine were not altered. The uptake of ornithine by the particulate fraction of the patient's fibroblasts was lower than that of controls, but still measurable. It is suggested that HHH patients have a partial impairment of the uptake of ornithine by mitochondria.

  14. Analysis list: TCP1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available TCP1 Digestive tract,Epidermis,Prostate + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/TCP...1.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/TCP1.5.tsv http://dbarc...hive.biosciencedbc.jp/kyushu-u/hg19/target/TCP1.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP...1.Digestive_tract.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP...1.Epidermis.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/TCP1.Prostate.tsv http://dbarchive.bios

  15. 浅析TCP/IP协议及其安全%Analysis on TCP/IP Protocol and Its Security

    Institute of Scientific and Technical Information of China (English)

    李东灵; 毛自民

    2012-01-01

    本文主要讨论TCP/IP协议内容,以及TCP/IP协议的安全问题和几种常见的网络攻击手段.%This paper mainly discusses the TCP/IP protocol, and TCP/IP protocol security problems and some common network attack means.

  16. TCP/IP Network In Process Control Plants%过程控制中的TCP/IP网络

    Institute of Scientific and Technical Information of China (English)

    牟连佳; 王立明

    2002-01-01

    提出TCP/IP在过程控制中的应用. 评价TCP/IP控制系统性能,通过传统控制系统与TCP/IP控制系统的比较,指出采用TCP/IP 控制系统的优缺点. 说明过程控制技术中,采用TCP/IP是一种更好的选择.

  17. Determination of homocitrulline in urine of patients with HHH syndrome by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Al-Dirbashi, Osama Y; Al-Hassnan, Zuhair N; Rashed, Mohamed S

    2006-12-01

    A liquid chromatography tandem mass spectrometric method is described for the analysis of homocitrulline in human urine, a key metabolite in the differential diagnosis of hyperammonemia, hyperornithinemia, homocitrullinuria (HHH) syndrome. Urine samples were prepared by mere five-fold dilution with a mixture of internal standards (2H2-citrulline and 2H3-creatinine) used for the simultaneous quantification of creatinine. Analytes were separated on a cyano column and eluted isocratically within seven min. Detection was achieved by monitoring transitions of 190 > 84 and 190 > 127 for homocitrulline, 178 > 115 for 2H2-citrulline, 114 > 44 for creatinine and 117 > 47 for 2H3-creatinine. Calibration curves were linear up to 100 micromol/L. Intraday (n = 7) and interday (n = 6) variations were less than 10%. In urine samples from three siblings confirmed to have HHH syndrome, homocitrulline levels were at 13.3 (74), 21.1 (50) and 108.2 (103) mmol/mol creatinine (micromol/L). Control values were 0-9 mmol/mol creatinine (n = 120). The current method solves specificity issues in homocitrulline determination often encountered with some ninhydrin-based systems (coelution with methionine) and some o-phthalaldehyde-based ones (coelution with taurine), and presents an attractive alternative with a relatively high throughput.

  18. TCP NCE: A unified solution for non-congestion events to improve the performance of TCP over wireless networks

    Directory of Open Access Journals (Sweden)

    Sreekumari Prasanthi

    2011-01-01

    Full Text Available Abstract In this article, we propose a unified solution called Transmission Control Protocol (TCP for Non-Congestion Events (TCP NCE, to overcome the performance degradation of TCP due to non-congestion events over wireless networks. TCP NCE is capable to reduce the unnecessary reduction of congestion window size and retransmissions caused by non-congestion events such as random loss and packet reordering. TCP NCE consists of three schemes. Detection of non-congestion events (NCE-Detection, Differentiation of non-congestion events (NCE-Differentiation and Reaction to non-congestion events (NCE-Reaction. For NCE-Detection, we compute the queue length of the bottleneck link using TCP timestamp and for NCE-Differentiation, we utilize the flightsize information of the network with a dynamic delay threshold value. We introduce a new retransmission algorithm called 'Retransmission Delay' for NCE-Reaction which guides the TCP sender to react to non-congestion events by properly triggering the congestion control mechanism. According to the extensive simulation results using qualnet network simulator, TCP NCE acheives more than 70% throughput gain over TCP CERL and more than 95% throughput improvement as compared to TCP NewReno, TCP PR, RR TCP, TCP Veno, and TCP DOOR when the network coexisted with congestion and non-congestion events. Also, we compared the accuracy and fairness of TCP NCE and the result shows significant improvement over existing algorithms in wireless networks.

  19. Dynamics of TCP traffic over ATM networks

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, S. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.; Romanow, A. [Sun Microsystems Inc., Mountain View, CA (United States)

    1994-08-01

    The authors investigate the performance of TCP (Transport Control Protocol) connections over ATM (Asynchronous Transfer Mode) networks without ATM-level congestion control, and compare it to the performance of TCP over packet-based networks. For simulations of congested networks, the effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. The low throughput is due to wasted bandwidth as the congested link transmits cells from ``corrupted`` packets, i.e., packets in which at least one cell is dropped by the switch. This fragmentation effect can be corrected and high throughput can be achieved if the switch drops whole packets prior to buffer overflow; they call this strategy Early Packet Discard. They also discuss general issues of congestion avoidance for best-effort traffic in ATM networks.

  20. Priority probability deceleration deadline-aware TCP

    Institute of Scientific and Technical Information of China (English)

    Jin Ye; Jing Lin; Jiawei Huang

    2015-01-01

    In modern data centers, because of the deadline-agnostic congestion control in transmission control protocol (TCP), many deadline-sensitive flows can not finish before their deadlines. Therefore, providing a higher deadline meeting ratio becomes a critical chal enge in the typical online data intensive (OLDI) ap-plications of data center networks (DCNs). However, a problem named as priority synchronization is found in this paper, which de-creases the deadline meeting ratio badly. To solve this problem, we propose a priority probability deceleration (P2D) deadline-aware TCP. By using the novel probabilistic deceleration, P2D prevents the priority synchronization problem. Simulation results show that P2 D increases the deadline meeting ratio by 20%compared with D2TCP.

  1. Dynamics of TCP traffic over ATM networks

    Energy Technology Data Exchange (ETDEWEB)

    Floyd, S. [Lawrence Berkeley Lab., CA (United States). Information and Computing Sciences Div.; Romanow, A. [Sun Microsystems Inc., Mountain View, CA (United States)

    1994-08-01

    The authors investigate the performance of TCP (Transport Control Protocol) connections over ATM (Asynchronous Transfer Mode) networks without ATM-level congestion control, and compare it to the performance of TCP over packet-based networks. For simulations of congested networks, the effective throughput of TCP over ATM can be quite low when cells are dropped at the congested ATM switch. The low throughput is due to wasted bandwidth as the congested link transmits cells from ``corrupted`` packets, i.e., packets in which at least one cell is dropped by the switch. This fragmentation effect can be corrected and high throughput can be achieved if the switch drops whole packets prior to buffer overflow; they call this strategy Early Packet Discard. They also discuss general issues of congestion avoidance for best-effort traffic in ATM networks.

  2. A Survey: variants of TCP in Ad-hoc networks

    Directory of Open Access Journals (Sweden)

    Komal Zaman

    2013-11-01

    Full Text Available MANET (Mobile Ad-hoc network forms a temporary network of wireless mobile nodes without any infrastructure where all nodes are allowed to move freely, configure themselves and interconnect with its neighbors to perform peer to peer communication and transmission. TCP (Transmission Control Protocol offers reliable, oriented connection and mechanism of end to end delivery. This article provides the review and comparison of existing variants of TCP for instance: The TCP Tahoe, The TCP Reno, The TCP New Reno, The Lite, The Sack, The TCP Vegas, Westwood and The TCP Fack. TCP’s performance depends on the type of its variants due to missing of congestion control or improper activation procedures such as Slow Start, Fast Retransmission, and Congestion Avoidance, Retransmission, Fast Recovery, Selective Acknowledgement mechanism and Congestion Control. This analysis is essential to be aware about a better TCP implementation for a specific scenario and then nominated a suitable one.

  3. Predicting TCP congestion through active and passive measurments

    OpenAIRE

    Hassan, Ismail Ali

    2005-01-01

    The Transmission Control Protocol (TCP) has proved to be a reliable transport protocol that has withstood the test of time. It is part of the TCP/IP protocol suite deployed on the Internet, and it currently supports a variety of underlying networking technologies such as Wireless, Satellite and High-Speed networks. The congestion control mechanism used by current implementation of TCP (known as TCP-Reno/new Reno) is based on the Additive Increase Multiple Decrease (AIMD) algorithm that wa...

  4. A survey of TCP over ad hoc networks

    NARCIS (Netherlands)

    Al Hanbali, Ahmad; Altman, Eitan; Nain, Philippe

    2005-01-01

    The Transmission Control Protocol (TCP) was designed to provide reliable end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless ad hoc networks can lead to TCP implemen

  5. NetBEUI, IPX/SPX and TCP/IP%NetBEUI、IPX/SPX、TCP/IP之比较

    Institute of Scientific and Technical Information of China (English)

    王敏琴

    2001-01-01

    目前较流行的通信协议有NetBEUI、IPX/SPX、TCP/IP等.NetBEUI适合小型局域网,IPX/SPX则为Novell网的通信协议,TCP/IP为Internet协议.IPX/SPX、TCP/IP为可路由协议.NetBEUI、IPX/SPX不需设置,TCP/IP需设置其"IP地址"、"子网掩码"、"默认网关"、"主机名"等.

  6. Running TCP/IP over ATM Networks.

    Science.gov (United States)

    Witt, Michael

    1995-01-01

    Discusses Internet protocol (IP) and subnets and describes how IP may operate over asynchronous transfer mode (ATM). Topics include TCP (transmission control protocol), ATM cells and adaptation layers, a basic architectural model for IP over ATM, address resolution, mapping IP to a subnet technology, and connection management strategy. (LRW)

  7. Detecting Intermediary Hosts by TCP Latency Measurements

    Science.gov (United States)

    Singh, Gurvinder; Eian, Martin; Willassen, Svein Y.; Mjølsnes, Stig Fr.

    Use of intermediary hosts as stepping stones to conceal tracks is common in Internet misuse. It is therefore desirable to find a method to detect whether the originating party is using an intermediary host. Such a detection technique would allow the activation of a number of countermeasures that would neutralize the effects of misuse, and make it easier to trace a perpetrator. This work explores a new approach in determining if a host communicating via TCP is the data originator or if it is acting as a mere TCP proxy. The approach is based on measuring the inter packet arrival time at the receiving end of the connection only, and correlating the observed results with the network latency between the receiver and the proxy. The results presented here indicate that determining the use of a proxy host is possible, if the network latency between the originator and proxy is larger than the network latency between the proxy and the receiver. We show that this technique has potential to be used to detect connections were data is sent through a TCP proxy, such as remote login through TCP proxies, or rejecting spam sent through a bot network.

  8. The Tcp conjugation system of Clostridium perfringens.

    Science.gov (United States)

    Wisniewski, Jessica A; Rood, Julian I

    2017-03-07

    The Gram-positive pathogen Clostridium perfringens possesses a family of large conjugative plasmids that is typified by the tetracycline resistance plasmid pCW3. Since these plasmids may carry antibiotic resistance genes or genes encoding extracellular or sporulation-associated toxins, the conjugative transfer of these plasmids appears to be important for the epidemiology of C. perfringens-mediated diseases. Sequence analysis of members of this plasmid family identified a highly conserved 35kb region that encodes proteins with various functions, including plasmid replication and partitioning. The tcp conjugation locus also was identified in this region, initially based on low-level amino acid sequence identity to conjugation proteins from the integrative conjugative element Tn916. Genetic studies confirmed that the tcp locus is required for conjugative transfer and combined with biochemical and structural analyses have led to the development of a functional model of the Tcp conjugation apparatus. This review summarises our current understanding of the Tcp conjugation system, which is now one of the best-characterized conjugation systems in Gram-positive bacteria.

  9. Structure-guided mutational analysis of the OB, HhH, and BRCT domains of Escherichia coli DNA ligase.

    Science.gov (United States)

    Wang, Li Kai; Nair, Pravin A; Shuman, Stewart

    2008-08-22

    NAD(+)-dependent DNA ligases (LigAs) are ubiquitous in bacteria and essential for growth. LigA enzymes have a modular structure in which a central catalytic core composed of nucleotidyltransferase and oligonucleotide-binding (OB) domains is linked via a tetracysteine zinc finger to distal helix-hairpin-helix (HhH) and BRCT (BRCA1-like C-terminal) domains. The OB and HhH domains contribute prominently to the protein clamp formed by LigA around nicked duplex DNA. Here we conducted a structure-function analysis of the OB and HhH domains of Escherichia coli LigA by alanine scanning and conservative substitutions, entailing 43 mutations at 22 amino acids. We thereby identified essential functional groups in the OB domain that engage the DNA phosphodiester backbone flanking the nick (Arg(333)); penetrate the minor grove and distort the nick (Val(383) and Ile(384)); or stabilize the OB fold (Arg(379)). The essential constituents of the HhH domain include: four glycines (Gly(455), Gly(489), Gly(521), Gly(553)), which bind the phosphate backbone across the minor groove at the outer margins of the LigA-DNA interface; Arg(487), which penetrates the minor groove at the outer margin on the 3 (R)-OH side of the nick; and Arg(446), which promotes protein clamp formation via contacts to the nucleotidyltransferase domain. We find that the BRCT domain is required in its entirety for effective nick sealing and AMP-dependent supercoil relaxation.

  10. Performance Evaluation of TCP over Mobile Ad hoc Networks

    CERN Document Server

    Ahmed, Foez; Islam, Nayeema; Debnath, Sumon Kumar

    2010-01-01

    With the proliferation of mobile computing devices, the demand for continuous network connectivity regardless of physical location has spurred interest in the use of mobile ad hoc networks. Since Transmission Control Protocol (TCP) is the standard network protocol for communication in the internet, any wireless network with Internet service need to be compatible with TCP. TCP is tuned to perform well in traditional wired networks, where packet losses occur mostly because of congestion. However, TCP connections in Ad-hoc mobile networks are plagued by problems such as high bit error rates, frequent route changes, multipath routing and temporary network partitions. The throughput of TCP over such connection is not satisfactory, because TCP misinterprets the packet loss or delay as congestion and invokes congestion control and avoidance algorithm. In this research, the performance of TCP in Adhoc mobile network with high Bit Error rate (BER) and mobility is studied and investigated. Simulation model is implement...

  11. Identification of a TcpC-TcpQ Outer Membrane Complex Involved in the Biogenesis of the Toxin-Coregulated Pilus of Vibrio cholerae

    OpenAIRE

    Bose, Niranjan; Taylor, Ronald K.

    2005-01-01

    The toxin-coregulated pilus (TCP) of Vibrio cholerae and the soluble TcpF protein that is secreted via the TCP biogenesis apparatus are essential for intestinal colonization. The TCP biogenesis apparatus is composed of at least nine proteins but is largely uncharacterized. TcpC is an outer membrane lipoprotein required for TCP biogenesis that is a member of the secretin protein superfamily. In the present study, analysis of TcpC in a series of strains deficient in each of the TCP biogenesis p...

  12. Summary of CARE-HHH Mini-Workshop on LHC Crab Cavity Validation, 21 August 2008

    CERN Document Server

    Calaga, R; Garoby, R; Linnecar, T; Tomás, R; Zimmermann, F; CERN. Geneva. BE Department

    2008-01-01

    A global LHC crab-cavity collaboration is rapidly advancing the R&D of a complete crab cavity cryomodule and performing the associated beam dynamics simulations compatible with a prototype test in the phase 0/I upgrade with the aim of establishing a full crab crossing scheme for the phase II upgrade of the LHC. A one day CARE-HHH mini-workshop was held on August 21, 2008 at CERN to discuss crab crossing in the LHC phase 0/I & II upgrades and this reports summarizes the activities of the four sessions that took place during the workshop. The goals of this crab-cavity workshop were fourfold: (1) to discuss prospects of crab cavities in LHC upgrades (2) to review the status of the cryomodule development and beam dynamics, (3) to establish validity requirements for LHC crab cavities which need to be demonstrated prior to their installation into the LHC, and (4) to provide guidance & coordination for the global collaborators.

  13. Media-TCP: A Quality-Centric TCP-Friendly Congestion Control for Multimedia Transmission

    CERN Document Server

    Shiang, Hsien-Po

    2009-01-01

    In this paper, we propose a quality-centric congestion control for multimedia streaming over IP networks, which we refer to as media-TCP. Unlike existing congestion control schemes that adapt a user's sending rate merely to the network condition, our solution adapts the sending rate to both the network condition and the application characteristics by explicitly considering the distortion impacts, delay deadlines, and interdependencies of different video packet classes. Hence, our media-aware solution is able to provide differential services for transmitting various packet classes and thereby, further improves the multimedia streaming quality. We model this problem using a Finite-Horizon Markov Decision Process (FHMDP) and determine the optimal congestion control policy that maximizes the long-term multimedia quality, while adhering to the horizon- TCP-friendliness constraint, which ensures long-term fairness with existing TCP applications. We show that the FHMDP problem can be decomposed into multiple optimal...

  14. TCP-ATCA: Improved Transmission Control Algorithm in Satellite Network

    Institute of Scientific and Technical Information of China (English)

    Liu Feng; Liu Hengna; Zhao Han

    2008-01-01

    An adaptive transmission control algorithm based on TCP (TCP-ATCA) is proposed to reduce the effects of long propagation de- lay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification (DRED-ECN) algorithm, and, moreover, the pertaining con- gestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unneces- sary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher (≥ 600 packet/s), and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.

  15. A New TCP Congestion Control Supporting RTT-Fairness

    Science.gov (United States)

    Ogura, Kazumine; Nemoto, Yohei; Su, Zhou; Katto, Jiro

    This paper focuses on RTT-fairness of multiple TCP flows over the Internet, and proposes a new TCP congestion control named “HRF (Hybrid RTT-Fair)-TCP”. Today, it is a serious problem that the flows having smaller RTT utilize more bandwidth than others when multiple flows having different RTT values compete in the same network. This means that a user with longer RTT may not be able to obtain sufficient bandwidth by the current methods. This RTT fairness issue has been discussed in many TCP papers. An example is CR (Constant Rate) algorithm, which achieves RTT-fairness by multiplying the square of RTT value in its window increment phase against TCP-Reno. However, the method halves its windows size same as TCP-Reno when a packet loss is detected. This makes worse its efficiency in certain network cases. On the other hand, recent proposed TCP versions essentially require throughput efficiency and TCP-friendliness with TCP-Reno. Therefore, we try to keep these advantages in our TCP design in addition to RTT-fairness. In this paper, we make intuitive analytical models in which we separate resource utilization processes into two cases: utilization of bottleneck link capacity and that of buffer space at the bottleneck link router. These models take into account three characteristic algorithms (Reno, Constant Rate, Constant Increase) in window increment phase where a sender receives an acknowledgement successfully. Their validity is proved by both simulations and implementations. From these analyses, we propose HRF-TCP which switches two modes according to observed RTT values and achieves RTT fairness. Experiments are carried out to validate the proposed method. Finally, HRF-TCP outperforms conventional methods in RTT-fairness, efficiency and friendliness with TCP-Reno.

  16. Wire-Compatible Unordered Delivery in TCP and TLS

    CERN Document Server

    Iyengar, Janardhan; Amin, Syed Obaid; Nowlan, Michael F; Tiwari, Nabin

    2011-01-01

    The performance of many common Internet applications can benefit from out-of-order delivery, a feature all IETF transports since TCP have included. Yet latency-sensitive applications still frequently build on in-order TCP despite its performance drawbacks, for reasons such as network compatibility and TCP's cultural inertia. We introduce uTCP, an API extension that adds out-of-order delivery support without changing TCP's wire protocol, by delivering received TCP segments to the application immediately on arrival along with sequence number metadata. To obtain robust out-of-order delivery across middleboxes that may re-segment TCP flows, the application employs a "record-marking" content encoding such as COBS, allowing the receiver to extract records from a byte stream with arbitrary holes. TLS can also serve as such an encoding, enabling applications to obtain out-of-order delivery in a stream indistinguishable in the network from conventional TLS over TCP. With uTCP, for example, voice/videoconferencing appl...

  17. Performance Analysis of Different MANET Specific TCP variants

    Directory of Open Access Journals (Sweden)

    Debajyoti Pal

    2012-09-01

    Full Text Available - Transmission Control Protocol(TCP is implemented in the transport layer of a MANET, which enjoys the advantage of reliable data transmission over the Internet. However, due to certain unique characteristics of a MANET, modification of classical TCP has been done so as to improve its performance in such an environment. Accordingly, several MANET specific TCP versions like TCP Reno, TCP New Reno, TCP Tahoe and TCP Vegas have come into prominence. This paper evaluates the performance of the different TCP versions for the same network topology over certain fixed parameters like number of packets generated/node, average packet loss, average delay incurred by the packets while in transit from source to destination and the processing time taken by the intermediate nodes. For routing purpose, we have assumed Ad-HocOn Demand Distance Vector Routing (AODV as the standard. To address the common issues of congestion control as with TCP, the experiment has been carried out under different network loading conditions that have been achieved by slowly increasing the node density.

  18. Updatable Queue Protocol Based On TCP For Virtual Reality Environment

    CERN Document Server

    Al-Howaide, Ala'a Z; Salhieh, Ayad M

    2011-01-01

    The variance in number and types of tasks required to be implemented within Distributed Virtual Environments (DVE) highlights the needs for communication protocols can achieve consistency. In addition, these applications have to handle an increasing number of participants and deal with the difficult problem of scalability. Moreover, the real-time requirements of these applications make the scalability problem more difficult to solve. In this paper, we have implemented Updatable Queue Abstraction protocol (UQA) on TCP (TCP-UQA) and compared it with original TCP, UDP, and Updatable Queue Abstraction based on UDP (UDP-UQA) protocols. Results showed that TCP-UQA was the best in queue management.

  19. Home telemonitoring in heart failure patients: the HHH study (Home or Hospital in Heart Failure)

    Science.gov (United States)

    Mortara, Andrea; Pinna, Gian Domenico; Johnson, Paul; Maestri, Roberto; Capomolla, Soccorso; La Rovere, Maria Teresa; Ponikowski, Piotr; Tavazzi, Luigi; Sleight, Peter

    2009-01-01

    Aims The Home or Hospital in Heart failure (HHH) study was a European Community-funded, multinational, randomized controlled clinical trial, conducted in the UK, Poland, and Italy, to assess the feasibility of a new system of home telemonitoring (HT). The HT system was used to monitor clinical and physiological parameters, and its effectiveness (compared with usual care) in reducing cardiac events in heart failure (HF) patients was evaluated. Measurements were patient-managed. Methods and results From 2002 to 2004, 461 HF patients (age 60 ± 11 years, New York Heart Association class 2.4 ± 0.6, left ventricular ejection fraction 29 ± 7%) were enrolled at 11 centres and randomized (1:2) to either usual outpatient care or HT administered as three randomized strategies: (i) monthly telephone contact; (ii) strategy 1 plus weekly transmission of vital signs; and (iii) strategy 2 plus monthly 24 h recording of cardiorespiratory activity. Patients completed 81% of vital signs transmissions, as well as 92% of cardiorespiratory recordings. Over a 12-month follow-up, there was no significant effect of HT in reducing bed-days occupancy for HF or cardiac death plus HF hospitalization. Post hoc analysis revealed a heterogeneous effect of HT in the three countries with a trend towards a reduction of events in Italy. Conclusion Home or Hospital in Heart failure indicates that self-managed HT of clinical and physiological parameters is feasible in HF patients, with surprisingly high compliance. Whether HT contributes to a reduction of cardiac events requires further investigation. PMID:19228800

  20. A novel R275X mutation of the SLC25A15 gene in a Japanese patient with the HHH syndrome.

    Science.gov (United States)

    Torisu, Hiroyuki; Kira, Ryutaro; Kanazawa, Naomi; Takemoto, Megumi; Sanefuji, Masafumi; Sakai, Yasunari; Tsujino, Seiichi; Hara, Toshiro

    2006-06-01

    The hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome (MIM 238970) is an autosomal recessive metabolic disorder caused by a deficiency of the mitochondrial ornithine transporter, one of the urea cycle components. Mutations in the SLC25A15 gene have been coupled to the HHH syndrome. We describe a Japanese female patient with the HHH syndrome due to a novel homozygous R275X SLC25A15 mutation and male sibling who presumably carried the same mutation. He exhibited slowly progressive deterioration with seizures, a gait disturbance due to polyneuropathy, episodic confusion, and died of acute encephalopathy at 34 years of age while the proband exhibited moderate mental retardation, seizures, mild spastic paraplegia, and deafness without neurological deterioration for more than 20 years. The clinical features of previously documented patients with the homozygous SLC25A15 mutation demonstrated that genotype did not simply correlate with clinical severity. The phenotypic variability might depend on other factors, such as dietary and other genetic ones.

  1. Performance Analysis of TCP-Reno and TCP-Sack in the Case of a Single Source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work explores the behavior of both TCP-Reno and TCP-Sack under a simple scenario, where a single TCP source transmits the packets continuously over a single bottleneck node characterized by its queue size, bandwidth and propagation delay. The analysis allows to derive the performance of TCP, the utilization tends to 75% of the bottleneck throughput when the bandwidth × propagation delay pipe becomes very large, while it tends to 100% when the queuing delays are predominant because the queue is never empty. In the transient analysis we show how the initial phase of the session can degrade the performances. These results are proved through simulation.

  2. TCP/IP Protocol and Information Security%TCP/IP协议与信息安全

    Institute of Scientific and Technical Information of China (English)

    陈彦君

    2011-01-01

    TCP/IP agreement, although there are serious security problems, but still has its own Security. In this paper, the TCP/IP protocol working principle were briefly reviewed in this paper, and discussed the TCP/IP protocol in information security is the safety and the safety of the existing problems. And to how the TCP/IP protocol to protect information security was briefly discussed in this paper.%TCP/IP协议虽然存在着严重的安全隐患,但是仍然有着其自己独有的安全性。本文对TCP/IP、协议工作原理进行了简要的介绍,讨论了TCP/IP协议在信息安全方面所具有的安全性与存在的安全问题,并对如何利用TCP/IP协议来保护信息安全进行了简要的探讨。

  3. Integration of Linux TCP and Simulation: Verification, Validation and Application

    Directory of Open Access Journals (Sweden)

    Songrith Kittiperachol

    2009-11-01

    Full Text Available Network simulator has been acknowledged as one of the most flexible means in studying and developing protocol as it allows virtually endless numbers of simulated network environments to be setup and protocol of interest to be fine-tuned without requiring any real-world complicated and costly network experiment. However, depending on researchers, the same protocol of interest can be developed in different ways and different implementations may yield the outcomes that do not accurately capture the dynamics of the real protocol. In the last decade, TCP, the protocol on which the Internet is based, has been extensively studied in order to study and reevaluate its performance particularly when TCP based applications and services are deployed in an emerging Next Generation Network (NGN and Next Generation Internet (NGI. As a result, to understand the realistic interaction of TCP with new types of networks and technologies, a combination of a real-world TCP and a network simulator seems very essential. This work presents an integration of real-world TCP implementation of Linux TCP/IP network stack into a network simulator, called INET. Moreover, verification and validation of the integrated Linux TCP are performed within INET framework to ensure the validity of the integration. The results clearly confirm that the integrated Linux TCP displays reasonable and consistent dynamics with respect to the behaviors of the real-world Linux TCP. Finally, to demonstrate the application of the INET with Linux TCP extension, algorithms of other Linux TCP variants and their dynamic over a large-bandwidth long-delay network are briefly presented.

  4. The HhH2/NDD domain of the Drosophila Nod chromokinesin-like protein is required for binding to chromosomes in the oocyte nucleus.

    Science.gov (United States)

    Cui, Wei; Hawley, R Scott

    2005-12-01

    Nod is a chromokinesin-like protein that plays a critical role in segregating achiasmate chromosomes during female meiosis. The C-terminal half of the Nod protein contains two putative DNA-binding domains. The first of these domains, known as the HMGN domain, consists of three tandemly repeated high-mobility group N motifs. This domain was previously shown to be both necessary and sufficient for binding of the C-terminal half of Nod to mitotic chromosomes in embryos. The second putative DNA-binding domain, denoted HhH(2)/NDD, is a helix-hairpin-helix(2)/Nod-like DNA-binding domain. Although the HhH(2)/NDD domain is not required or sufficient for chromosome binding in embryos, several well-characterized nod mutations have been mapped in this domain. To characterize the role of the HhH(2)/NDD domain in mediating Nod function, we created a series of UAS-driven transgene constructs capable of expressing either a wild-type Nod-GFP fusion protein or proteins in which the HhH(2)/NDD domain had been altered by site-directed mutagenesis. Although wild-type Nod-GFP localizes to the oocyte chromosomes and rescues the segregation defect in nod mutant oocytes, two of three proteins carrying mutants in the HhH(2)/NDD domain fail to either rescue the nod mutant phenotype or bind to oocyte chromosomes. However, these mutant proteins do bind to the polytene chromosomes in nurse-cell nuclei and enter the oocyte nucleus. Thus, even though the HhH(2)/NDD domain is not essential for chromosome binding in other cell types, it is required for chromosome binding in the oocyte. These HhH(2)/NDD mutants also block the localization of Nod to the posterior pole of stage 9-10A oocytes, a process that is thought to facilitate the interaction of Nod with the plus ends of microtubules (Cui et al. 2005). This observation suggests that the Nod HhH2/NDD domain may play other roles in addition to binding Nod to meiotic chromosomes.

  5. 轻量级嵌入式TCP/IP协议栈的设计%Design of Light-weight TCP/IP Stack in Embedded System

    Institute of Scientific and Technical Information of China (English)

    王力生; 梅岩; 曹南洋

    2007-01-01

    介绍了引入轻量级TCP/IP协议栈的背景,描述了标准TCP/IP协议栈,分析了嵌入式系统中TCP/IP协议栈的特点和设计的思路,总结了轻量级TCP/IP协议栈和标准TCP/IP协议栈的区别.

  6. Microwave sintering of nano size powder β-TCP bioceramics

    Directory of Open Access Journals (Sweden)

    Mirhadi B.

    2014-01-01

    Full Text Available A nano sized beta tricalcium phosphate (β-TCP powder was conventional sintered (CS and microwave sintered (MW, in order to obtain dense β-TCP ceramics. In this work the effect of microwave sintering conditions on the microstructure, phase composition and mechanical properties of materials based on tricalcium phosphate (TCP was investigated by SEM (scanning electron microscopyand XRD(X-ray diffraction and then compared with conventional sintered samples. Nano-size β-TCP powders with average grain size of 80 nm were prepared by the wet chemical precipitation method with calcium nitrate and diammonium hydrogen phosphate as calcium and phosphorus precursors, respectively. The precipitation process employed was also found to be suitable for the production of submicrometre β-TCP powder in situ. The β-TCP samples microwave (MW sintered for 15 min at 1100°C, with average grain size of 3μm, showed better densification, higher density and certainly higher hardness than samples conventionally sintered for 2 h at the same temperature. By comparing sintered and MW sintered β-TCP samples, it was concluded that MW sintered β-TCP samples have superior mechanical properties.

  7. Optimising TCP for cloud-based mobile networks

    DEFF Research Database (Denmark)

    Artuso, Matteo; Christiansen, Henrik Lehrmann

    2016-01-01

    protocols should therefore be adjusted to cope with the peculiarities of these networks. In this paper, we investigate an optimized design of the Transmission Control Protocol (TCP), as it plays a central role in all-IP mobile networks to ensure optimal performances for application-layer services. TCP...

  8. Development and Characterization of Biphasic Hydroxyapatite/β-TCP Cements.

    Science.gov (United States)

    Gallinetti, Sara; Canal, Cristina; Ginebra, Maria-Pau; Ferreira, J

    2014-04-01

    Biphasic calcium phosphate bioceramics composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have relevant properties as synthetic bone grafts, such as tunable resorption, bioactivity, and intrinsic osteoinduction. However, they have some limitations associated to their condition of high-temperature ceramics. In this work self-setting Biphasic Calcium Phosphate Cements (BCPCs) with different HA/β-TCP ratios were obtained from self-setting α-TCP/β-TCP pastes. The strategy used allowed synthesizing BCPCs with modulated composition, compressive strength, and specific surface area. Due to its higher solubility, α-TCP was fully hydrolyzed to a calcium-deficient HA (CDHA), whereas β-TCP remained unreacted and completely embedded in the CDHA matrix. Increasing amounts of the non-reacting β-TCP phase resulted in a linear decrease of the compressive strength, in association to the decreasing amount of precipitated HA crystals, which are responsible for the mechanical consolidation of apatitic cements. Ca(2+) release and degradation in acidic medium was similar in all the BCPCs within the timeframe studied, although differences might be expected in longer term studies once β-TCP, the more soluble phase was exposed to the surrounding media.

  9. Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach

    Science.gov (United States)

    Scott, Keith; Czetty, Stephen

    1998-01-01

    Various issues associated with "Improving TCP Performance over Mobile Satellite Channels: The ACKPrime Approach" are presented in viewgraph form. Specific topics include: 1) TCP over mobile satellite links; 2) ways of breaking the control loop at the groundstation; 3) ACK implementation; and 4) ACK performance.

  10. Genome-wide analysis of TCP family in tobacco.

    Science.gov (United States)

    Chen, L; Chen, Y Q; Ding, A M; Chen, H; Xia, F; Wang, W F; Sun, Y H

    2016-05-23

    The TCP family is a transcription factor family, members of which are extensively involved in plant growth and development as well as in signal transduction in the response against many physiological and biochemical stimuli. In the present study, 61 TCP genes were identified in tobacco (Nicotiana tabacum) genome. Bioinformatic methods were employed for predicting and analyzing the gene structure, gene expression, phylogenetic analysis, and conserved domains of TCP proteins in tobacco. The 61 NtTCP genes were divided into three diverse groups, based on the division of TCP genes in tomato and Arabidopsis, and the results of the conserved domain and sequence analyses further confirmed the classification of the NtTCP genes. The expression pattern of NtTCP also demonstrated that majority of these genes play important roles in all the tissues, while some special genes exercise their functions only in specific tissues. In brief, the comprehensive and thorough study of the TCP family in other plants provides sufficient resources for studying the structure and functions of TCPs in tobacco.

  11. Passive TCP Reconstruction and Forensic Analysis with tcpflow

    Science.gov (United States)

    2013-09-01

    the libnids interface, allow- ing direct comparison of speed and accuracy of the two passive TCP implementations. We plan to publish a set of pcap...packet hashes to prevent TCP retransmit overwrite attacks, March 3 2009. US Patent 7500264. [13] H. Hibshi, T. Vidas , and L. Cranor. Usability of forensics

  12. Transformation and biodegradation of 1,2,3-trichloropropane (TCP)

    NARCIS (Netherlands)

    Samin, Ghufrana; Janssen, Dick B.

    2012-01-01

    1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen. It is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture. In view of the spread of TCP via groundwater and its toxicity, there is a need for

  13. Transformation and biodegradation of 1,2,3-trichloropropane (TCP)

    NARCIS (Netherlands)

    Samin, Ghufrana; Janssen, Dick B.

    1,2,3-Trichloropropane (TCP) is a persistent groundwater pollutant and a suspected human carcinogen. It is also is an industrial chemical waste that has been formed in large amounts during epichlorohydrin manufacture. In view of the spread of TCP via groundwater and its toxicity, there is a need for

  14. Recent TCP(Tidal Current Power) projects in Korea

    Institute of Scientific and Technical Information of China (English)

    Chul; Hee; JO; Kang; Hee; LEE; Yu; Ho; RHO

    2010-01-01

    Having strong current on the west coast with up to 10 m tidal range in Korea,there are many suitable and applicable locations for TCP(Tidal Current Power) application in Korea.Not only the west coast,but also the south west regions having narrow channels between islands creating fast ocean stream are suitable for TCP.The first TCP application in Korea is 1 MW helical VAT(Vertical Axis Turbine) device installed in Wooldolmog area in 2008.The first HAT(Horizontal Axis Turbine) TCP device of 25 KW was developed and installed in cooling water weir of Samchonpo power plant in 2008.Furthermore,a 100 kW prototype HAT TCP device is being planned to be installed in Daebang strait in 2009.Another big project would be Inchon TCP farm of 200 MW on the west coast in Korea.The consortium of 5 members was formed in April,2009.This site will be the largest TCP site in the world.The paper describes recent TCP projects in Korea with background and environmental conditions of the projects.

  15. Analysis of two competing TCP/IP connections

    NARCIS (Netherlands)

    Altman, E.; Jiménez, T.; Núñez Queija, R.

    2001-01-01

    Many mathematical models exist for describing the behavior of TCP/IP under an exogenous loss process that does not depend on the window size. The goal of this paper is to present a mathematical analysis of two asymmetric competing TCP connections where loss probabilities are directly related to thei

  16. THE FAILURE OF TCP IN HIGH-PERFORMANCE COMPUTATIONAL GRIDS

    Energy Technology Data Exchange (ETDEWEB)

    W. FENG; ET AL

    2000-08-01

    Distributed computational grids depend on TCP to ensure reliable end-to-end communication between nodes across the wide-area network (WAN). Unfortunately, TCP performance can be abysmal even when buffers on the end hosts are manually optimized. Recent studies blame the self-similar nature of aggregate network traffic for TCP's poor performance because such traffic is not readily amenable to statistical multiplexing in the Internet, and hence computational grids. In this paper we identify a source of self-similarity previously ignored, a source that is readily controllable--TCP. Via an experimental study, we examine the effects of the TCP stack on network traffic using different implementations of TCP. We show that even when aggregate application traffic ought to smooth out as more applications' traffic are multiplexed, TCP induces burstiness into the aggregate traffic loud, thus adversely impacting network performance. Furthermore, our results indicate that TCP performance will worsen as WAN speeds continue to increase.

  17. RATE-ADJUSTMENT ALGORITHM FOR AGGREGATE TCP CONGESTION CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    P. TINNAKORNSRISUPHAP, ET AL

    2000-09-01

    The TCP congestion-control mechanism is an algorithm designed to probe the available bandwidth of the network path that TCP packets traverse. However, it is well-known that the TCP congestion-control mechanism does not perform well on networks with a large bandwidth-delay product due to the slow dynamics in adapting its congestion window, especially for short-lived flows. One promising solution to the problem is to aggregate and share the path information among TCP connections that traverse the same bottleneck path, i.e., Aggregate TCP. However, this paper shows via a queueing analysis of a generalized processor-sharing (GPS) queue with regularly-varying service time that a simple aggregation of local TCP connections together into a single aggregate TCP connection can result in a severe performance degradation. To prevent such a degradation, we introduce a rate-adjustment algorithm. Our simulation confirms that by utilizing our rate-adjustment algorithm on aggregate TCP, connections which would normally receive poor service achieve significant performance improvements without penalizing connections which already receive good service.

  18. A Throughput Analysis of TCP in ADHOC Networks

    Directory of Open Access Journals (Sweden)

    S.P.Valli

    2013-07-01

    Full Text Available Transmission Control Protocol (TCP is a connection oriented end-end reliable byte stream transport layer protocol. It is widely used in the Internet.TCP is fine tuned to perform well in wired networks. However the performance degrades in mobile ad hoc networks. This is due to the characteristics specific to wireless networks, such as signal fading, mobility, unavailability of routes. This leads to loss of packets which may arise either from congestion or due to other non-congestion events. However TCP assumes every lo ss as loss due to congestion and invokes the congestion control procedures. TCP reduces cong estion window in response, causing unne- cessary degradation in throughput. In mobile ad hoc networks multi-hop path forwarding fur- ther worsens the packet loss and throughput. To und erstand the TCP behavior and improve the TCP performance over mobile ad hoc networks conside rable research has been carried out. As the research is still active in this area a compreh ensive and in-depth study on the TCP through- put and the various parameters that degrade the per formance of TCP have been analyzed. The analysis is done using simulations in Qualnet 5.0

  19. Novel evaluation method of TCP performance over satellite links

    Institute of Scientific and Technical Information of China (English)

    Wang Lina; Gu Xuemai

    2006-01-01

    A novel and efficient method to evaluate the transmission control protocol (TCP) performance over satellite links is presented. A TCP module is divided into three functional blocks, namely data processing, congestion control and error control. The re-established TCP module is easy to update TCP congestion control strategy or error control strategy. With the proposed analysis approach, the interactions between different congestion control and error control mechanisms, as well as the performance of various combination protocols in satellite environments have been investigated. Simulation results obtained through a series of experiments have shown that SNACK-based error control strategy can perform well with any other congestion control strategy. The best performance can be achieved by TCP New Reno congestion control strategy and SNACK-based error control strategy.

  20. Enhancing the Flexibility of TCP in Heterogeneous Network.

    Science.gov (United States)

    Hui, Wang; Peiyu, Li; Zhihui, Fan; Zheqing, Li; Xuhui, Wei

    Due to a set of constant initial values, the performance of conventional TCP drops significantly encountering heterogeneous network, showing low throughput and unfairness. This paper firstly demonstrates the chaotic character of TCP congestion control in heterogeneous network, especially the sensitivity to initial value. Inspired by merit of nature-inspired algorithm, a novel structure of TCP congestion control (IPPM, Internet Prey-Predator Model) is proposed. Parameters such as available link capacity(C), congestion window (W) and queue length (Q) are collected by IPPM, which calculates the max value of C according to the interacting relationship existing in C, W and Q, and IPPM initiates the TCP ssthresh with the calculated value. Plenty of simulation results show that the modified TCP can effectively avoid network congestion and packet loss. Besides, it holds high resource utilization, convergence speeds, fairness and stability.

  1. Chitosan Fibers Modified with HAp/β–TCP Nanoparticles

    Directory of Open Access Journals (Sweden)

    Dariusz Wawro

    2011-10-01

    Full Text Available This paper describes a method for preparing chitosan fibers modified with hydroxyapatite (HAp, tricalcium phosphate (β-TCP, and HAp/β-TCP nanoparticles. Fiber-grade chitosan derived from the northern shrimp (Pandalus borealis and nanoparticles of tricalcium phosphate (β-TCP and hydroxyapatite (HAp suspended in a diluted chitosan solution were used in the investigation. Diluted chitosan solution containing nanoparticles of Hap/β-TCP was introduced to a 5.16 wt% solution of chitosan in 3.0 wt% acetic acid. The properties of the spinning solutions were examined. Chitosan fibers modified with nanoparticles of HAp/β-TCP were characterized by a level of tenacity and calcium content one hundred times higher than that of regular chitosan fibers.

  2. A comparative study of aggregate TCP retransmission rates

    CERN Document Server

    Pentikousis, Kostas; Andrade, Asha; 10.2316/Journal.202.2010.4.202-2660

    2011-01-01

    Segment retransmissions are an essential tool in assuring reliable end-to-end communication in the Internet. Their crucial role in TCP design and operation has been studied extensively, in particular with respect to identifying non-conformant, buggy, or underperforming behaviour. However, TCP segment retransmissions are often overlooked when examining and analyzing large traffic traces. In fact, some have come to believe that retransmissions are a rare oddity, characteristically associated with faulty network paths, which, typically, tend to disappear as networking technology advances and link capacities grow. We find that this may be far from the reality experienced by TCP flows. We quantify aggregate TCP segment retransmission rates using publicly available network traces from six passive monitoring points attached to the egress gateways at large sites. In virtually half of the traces examined we observed aggregate TCP retransmission rates exceeding 1%, and of these, about half again had retransmission rate...

  3. [A case of hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome with spastic paraparesis and severe distal muscle atrophy of lower limbs].

    Science.gov (United States)

    Shigeto, H; Yamada, T; Kobayashi, T; Goto, I

    1992-07-01

    A 16-year-old boy with hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome was reported. He was the second child of first-cousin consanguineous parents. Since childhood, he was mentally retarded and had frequent episodes of vomiting but no unconsciousness attack. Because of progressive gait disturbance since the age of 15, he was admitted to Kyushu University Hospital. Neurological examination revealed mental defect and spastic paraparesis with bilateral positive pathological reflexes. Moreover, severe muscle atrophy and moderate weakness were observed in the distal portion of lower extremities. The diagnosis of HHH syndrome was made by the examination of amino acids in the serum and urine and by the incorporation study of radioactive ornithine into cultured fibroblasts. EMG and nerve biopsy studies suggested that the muscle atrophy seen in this patient was caused by the degeneration of spinal anterior horn cells. Amino acid imbalance, especially elevation of glutamine and glutamic acid in the CSF, may cause dysfunction of neuronal system including anterior horn cells.

  4. Identification of novel mutations in the SLC25A15 gene in hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome: a clinical, molecular, and functional study.

    Science.gov (United States)

    Tessa, Alessandra; Fiermonte, Giuseppe; Dionisi-Vici, Carlo; Paradies, Eleonora; Baumgartner, Matthias R; Chien, Yin-Hsiu; Loguercio, Carmela; de Baulny, Helene Ogier; Nassogne, Marie-Cecile; Schiff, Manuel; Deodato, Federica; Parenti, Giancarlo; Rutledge, S Lane; Vilaseca, M Antonia; Melone, Mariarosa A B; Scarano, Gioacchino; Aldamiz-Echevarría, Luiz; Besley, Guy; Walter, John; Martinez-Hernandez, Eugenia; Hernandez, Jose M; Pierri, Ciro L; Palmieri, Ferdinando; Santorelli, Filippo M

    2009-05-01

    Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is an autosomal recessive disorder of the urea cycle. With the exception of the French-Canadian founder effect, no common mutation has been detected in other populations. In this study, we collected 16 additional HHH cases and expanded the spectrum of SLC25A15/ORC1 mutations. Eleven novel mutations were identified including six new missense and one microrearrangement. We also measured the transport properties of the recombinant purified proteins in reconstituted liposomes for four new and two previously reported missense mutations and proved that the transport activities of these mutant forms of ORC1 were reduced as compared with the wild-type protein; residual activity ranged between 4% and 19%. Furthermore, we designed three-dimensional (3D)-modeling of mutant ORC1 proteins. While modeling the changes in silico allowed us to obtain new information on the pathomechanisms underlying HHH syndrome, we found no clear-cut genotype-phenotype correlations. Although patient metabolic alterations responded well to low-protein therapy, predictions concerning the long-term evolution of HHH syndrome remain uncertain. The preference for a hepatic rather than a neurological presentation at onset also continues, largely, to elude us. Neither modifications in oxidative metabolism-related energy, such as those expected in different mtDNA haplogroups, nor sequence variants in SLC25A2/ORC2 seem to be crucial. Other factors, including protein stability and function, and ORC1-ORC2 structural interactions should be further investigated.

  5. The human and mouse SLC25A29 mitochondrial transporters rescue the deficient ornithine metabolism in fibroblasts of patients with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome.

    Science.gov (United States)

    Camacho, José A; Rioseco-Camacho, Natalia

    2009-07-01

    The hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is a disorder of the urea cycle (UCD) and ornithine degradation pathway caused by mutations in the mitochondrial ornithine transporter (ORNT1). Unlike other UCDs, HHH syndrome is characterized by a less severe and variable phenotype that we believe may, in part, be due to genes with redundant function to ORNT1, such as the previously characterized ORNT2 gene. We reasoned that SLC25A29, a member of the same subfamily of mitochondrial carrier proteins as ORNT1 and ORNT2, might also have overlapping function with ORNT1. Here, we report that both the human and mouse SLC25A29, previously identified as mitochondrial carnitine/acyl-carnitine transporter-like, when overexpressed transiently also rescues the impaired ornithine transport in cultured HHH fibroblasts. Moreover, we observed that, in the mouse, the Slc25a29 message is more significantly expressed in the CNS and cultured astrocytes when compared with the liver and kidney. These results suggest a potential physiologic role for the SLC25A29 transporter in the oxidation of fatty acids, ornithine degradation pathway, and possibly the urea cycle. Our results show that SLC25A29 is the third human mitochondrial ornithine transporter, designated as ORNT3, which may contribute to the milder and variable phenotype seen in patients with HHH syndrome.

  6. TCP/IP Over SpaceWire

    Science.gov (United States)

    Mills, S.; Parkes, S.

    The SpaceWire standard defines a network designed for handling payload data and control information onboard a spacecraft. Among the goals of SpaceWire are re-usability and reliability. The use of network protocols on top of SpaceWire is expected to enhance the already rich re-usability and reliability characteristics of SpaceWire. The Space Systems Research Group at the University of Dundee have developed software to allow data to be sent over SpaceWire using standard network protocols such as TCP/IP, as part of a program of work looking at network protocols for SpaceWire. This paper describes network protocols and their relationship to SpaceWire, introduces software written to allow network protocols to be layered on to SpaceWire, describes the research behind the development of this software, and gives results of some tests and observations made using the software.

  7. A Novel Wireless TCP and its Steady State Throughput Model

    Institute of Scientific and Technical Information of China (English)

    YAO Ling; JI Hong; YUE Guang-xin

    2004-01-01

    Unlike wired networks, random packet loss due to bit errors may cause significant performance degradation of Transmission Control Protocol (TCP). We propose and study a novel end-to-end congestion control mechanism called TCP-LD (Loss Detection) that is simple and effective for dealing with random packet loss. We also give its steady state throughput model. Both the ns2 and numerical simulation results show that our scheme can achieve significant throughput improvements without adversely affecting other concurrent TCP connections, including other concurrent Reno connections both in wired and wireless environment.

  8. Allocating Network Resources by Weight Between TCP Traffics

    Institute of Scientific and Technical Information of China (English)

    xU ChangBiao(徐昌彪); LONG KePing(隆克平); YANG ShiZhong(杨士中)

    2003-01-01

    Under the current TCP/IP architecture, all TCP traffics compete for networkresources completely fairly, which makes it difficult to satisfy applications' versatile communicationrequirements. This paper presents an improved TCP congestion control mechanism where thecongestion window becomes ω(1 - b)W rather than (1 - b)W for every window W containing apacket loss. Theoretical analysis and simulation results show that it can be easily implementedwith less additional overhead and can easily perform network resource allocation by weightedparameter w for traffics under the similar communication environments, which can efficiently leadto guaranteed relative quality of services and improve network performances.

  9. In Vitro Characterizations of PLLA/β-TCP Porous Matrix Materials and RMSC-PLLA-β-TCP Composite Scaffolds

    Institute of Scientific and Technical Information of China (English)

    Dali ZHOU; Weizhong YANG; Guangfu Yin; Changqiong ZHENG; Yun ZHANG; Huaiqing CHEN; Rui CHEN

    2004-01-01

    To develop a novel degradable poly (L-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) bioactive materials for bone tissue engineering, β-TCP powder was produced by a new wet process. Porous scaffolds were prepared by three steps, I.e. Solvent casting, compression molding and leaching stage. Factors influencing the compressive strength and the degradation behavior of the porous scaffold, e.g. Weight fraction of pore forming agent-sodium chloride (NaCl), weight ratio of PLLA: β-TCP, the particle size ofβ-TCP and the porosity, were discussed in details. Rat marrow stromal cells (RMSC) were incorporated into the composite by tissue engineering approach. Biological and osteogenesis potential of the composite scaffold were determined with MTT assay, alkaline phosphatase (ALP) activity and bone osteocalcin (OCN) content evaluation. Results show that PLLA/β-TCP bioactive porous scaffold has good mechanical and pore structure with adjustable compressive strength needed for surgery. RMSCs seeding on porous PLLA/β-TCP composite behaves good seeding efficacy, biocompatibility and osteoinductive potential. Osteoprogenitor cells could well penetrate into the material matrix and begin cell proliferation and osteogenic differentiation. Osseous matrix could be formed on the surface of the composite after culturing in vitro. It is expected that the PLLA/β-TCP porous composites are promising scaffolds for bone tissue engineering in prosthesis surgery.

  10. Analysis and Improvement of TCP Congestion Control Mechanism Based on Global Optimization Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Network flow control is formulated as a global optimization problem of user profit. A general global optimization flow control model is established. This model combined with the stochastic model of TCP is used to study the global rate allocation characteristic of TCP. Analysis shows when active queue manage ment is used in network TCP rates tend to be allocated to maximize the aggregate of a user utility function Us (called Us fairness). The TCP throughput formula is derived. An improved TCP congestion control mecha nism is proposed. Simulations show its throughput is TCP friendly when competing with existing TCP and its rate change is smoother. Therefore, it is suitable to carry multimedia applications.

  11. TCP Congestion Control for the Networks with Markovian Jump Parameters

    Directory of Open Access Journals (Sweden)

    MOMENI, H. R.

    2011-05-01

    Full Text Available This paper is concerned with the problem of TCP congestion control for the class of communication networks with random parameters. The linear dynamic model of TCP New Reno in congestion avoidance mode is considered which contains round trip delays in both state and input. The randomness of link capacity, round trip time delay and the number of TCP sessions is modeled with a continuous-time finite state Markov process. An Active Queue Management (AQM technique is then used to adjust the queue level of the congested link to a predefined value. For this purpose, a dynamic output feedback controller with mode dependent parameters is synthesized to stochastically stabilize the TCP/AQM dynamics. The procedure of the control synthesis is implemented by solving a linear matrix inequality (LMI. The results are tested within a simulation example and the effectiveness of the proposed design method is verified.

  12. Mixing TCP and Satellites: A View from Above

    Science.gov (United States)

    Travis, Eric

    1998-01-01

    Various issues associated with "Mixing TCP and Satellites: A View from Above" are presented in viewgraph form. Specific topics include: 1) Why are open protocol standards important?; and 2) Protocols are like galoshes: One size does not fit all.

  13. TCP TRAFFIC PERFORMANCE IMPROVING IN LTE-A NETWORKS

    Institute of Scientific and Technical Information of China (English)

    Yang Bo; Wu Weimin; Zhu Guangxi; Yu Hongtao

    2013-01-01

    This paper presents a novel way to improve Transmission Control Protocol (TCP) performance of the users at the edge areas of the macro cells in Long Term Evolution Advanced (LTE-A) systems.Previous works on improving wireless TCP performance are reviewed and current considerations on TCP in LTE-A are explained.Howev5r,those solutions are neither too complex nor limited to some presuppositions which are too restricting for the deployment of LTE-A networks.In this paper a substituted TCP acknowledgement transmission scheme based on Automatic Repeat reQuest (ARQ) information in layer 2 is proposed.The simulation result shows that the proposed method can reduce the delay and improve the throughput of the edging users of the cell,as well as reducing radio resources in LTE-A macro cells.

  14. Identifying online traffic based on property of TCP flow

    Institute of Scientific and Technical Information of China (English)

    HONG Min-huo; GU Ren-tao; WANG Hong-xiang; SUN Yong-mei; JI Yue-feng

    2009-01-01

    Classification of network traffic using port-based or payload-based analysis is becoming increasingly difficult when many applications use dynamic port numbers, masquerading techniques, and encryption to avoid detection. In this article, an approach is presented for online traffic classification relying on the observation of the first n packets of a transmission control protocol (TCP) connection. Its key idea is to utilize the properties of the observed first ten packets of a TCP connection and Bayesian network method to build a classifier. This classifier can classify TCP flows dynamically as packets pass through it by deciding whether a TCP flow belongs to a given application. The experimental results show that the proposed approach performs well in online Internet traffic classification and that it is superior to naive Bayesian method.

  15. Optimization of the transmission mechanism for wireless TCP

    Institute of Scientific and Technical Information of China (English)

    QU Zhao-wei; ZHANG Juan

    2008-01-01

    A novel method which can detect the possible handoffsfor mobile nodes is proposed in this article. The method can bedeployed on mobile nodes. So when a possible handoff occurs,mobile nodes can detect and take some necessary actions intime. In this study, the method is also used to optimize thetransmission mechanism of Q-TCP. Moreover, the simulationresults show that Q-TCP can provide better quality of service(QoS) for mobile nodes when they are moving among differentagents.

  16. TCP-IP Model in Data Communication and Networking

    OpenAIRE

    Pranab Bandhu Nath; Md.Mofiz Uddin

    2015-01-01

    The Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP, because it’s most important protocols, the Transmission Control Protocol (TCP) and the Internet Protocol (IP), were the first networking protocols defined in this standard. Often also called the Internet model, it was originally also known as the DoD model, because the development of the networking mode...

  17. Biological Evaluation of α-TCP/TTCP Composite Bone Cement

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    α-tricalcium phosphate(α-TCP)/tetracalcium phosphate(TTCP) composite bone cement had good hydration characteristic.In our system,α-TCP/TTCP powder mixture was mixed with water at a powder/liquid (P/L) ratio of 1.50g*mL-1.The setting time could be adjusted,the maximum compressive strength was 45.36MPa,and the hydration product was hydroxyapatite (HAP).In vitro biological simulated experiments indicate that α-TCP/TTCP bone cement has α certain dissolubility.The hardened product is mainly HAP after soaking in simulated body fluid (SBF) for 10 weeks.The results of in vitro test and animal experiments and SEM analyses show that no local or general toxicity response,no muscle stimulation,no haemolysis,no cruor,no inflammatory reaction and no exclusion response are caused by α-TCP/TTCP cement, which can be contributed to bone tissue spreading and impinging.α-TCP/TTCP cement hydrated and hardened continually in vivo.The materials fused with host bone together with implanting time prolonging.Therefore,it is believed that α-TCP/TTCP composite bone cement has a high biocompatibility and bioactivity,a certain biodegradation and good osteogenesis as well.

  18. TCP Packet Trace Analysis. M.S. Thesis

    Science.gov (United States)

    Shepard, Timothy J.

    1991-01-01

    Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

  19. Analysis of TCP performance in data center networks

    CERN Document Server

    Kulkarni, Santosh

    2014-01-01

    This book addresses the need to improve TCP’s performance inside data centers by providing solutions that are both practical and backward compatible with standard TCP versions. The authors approach this challenge first by deriving an analytical model for TCP’s performance under typical data center workload traffic.  They then discuss some solutions that are designed to improve TCP performance by either proactively detecting network congestion through probabilistic retransmission or by avoiding timeout penalty through dynamic resizing of TCP segments. Experimental results show that each of techniques discussed outperforms standard TCP inside a data center.  ·         Analyzes the reasons behind TCP performance slump inside data centers when operating under synchronized workload traffic; ·         Introduces solutions to TCP performance slump inside data centers that are both practical and backward compatible; ·         Describes mechanisms that are responsible for TCP’s relia...

  20. Global Connections for Lasting Impressions: Experiential Learning about TCP

    Science.gov (United States)

    Allison, Colin; Miller, Alan; Oliver, Iain; Sturgeon, Thomas

    “Tell me and I forget, Show me and I remember, Involve me and I understand”. This paper discusses the motivation for, and design of, a learning resource which allows students to explore the Transmission Control Protocol (TCP). TCP is responsible for transporting over 80% of the traffic on the Internet - all web and e-mail for example - and in addition is the primary means of achieving Internet congestion control. TCP is therefore core to modern life. It is a protocol under constant study with a view to evolution, and it is incumbent on all ICT curricula to provide education at appropriate levels about its dynamics, strengths and weaknesses. There are no shortages of good textbooks which provide information on TCP, but these are no substitute for experiential learning in order to provide a lasting understanding. The TCP Live learning resource allows students to explore the behavior of TCP on the global Internet, and see the wide variety of conditions that the protocol has to cope with, thereby extending their viewpoint outwith the limited scope of their own institutional firewalls.

  1. TCP I-Vegas in Mobile-IP Network

    Directory of Open Access Journals (Sweden)

    Nitin Jain

    2014-01-01

    Full Text Available Mobile Internet Protocol (Mobile-IP or MIP provides hosts with the ability to change their point of attachment to the network without compromising their ability to communicate. However, when TCP Vegas is used over a MIP network, its performance degrades because it may respond to a handoff by invoking its congestion control algorithm. TCP Vegas is sensitive to the change of Round-Trip Time (RTT and it may recognize the increased RTT as a result of network congestion. This is because TCP Vegas could not differentiate whether the increased RTT is due to route change or network congestion. This paper presents a new and improved version of conventional TCP Vegas, which we named as TCP I-Vegas (where “I”, stands for Improved. Vegas performs well when compared to Reno but when sharing bandwidth with Reno its performance degrades. I-Vegas has been designed keeping in mind that whenever TCP variants like Reno has to share the bandwidth with Vegas then instead of using Vegas, if we use I-Vegas then the loss which Vegas would have to bear will not be more. We compared the performance of I-Vegas with Vegas in MIP environment using Network Simulator (NS-2. Simulation results show that I-Vegas performs better than Vegas in terms of providing better throughput and congestion window behavior.

  2. 开放的MODBUS TCP (连载二)

    Institute of Scientific and Technical Information of China (English)

    华镕

    2005-01-01

    @@ 1为什么要用TCP/IP? TCP/IP ( Transmission Control Protocol / Intemet Protocol,传送控制协议/网际协议)之所以强大的最主要的一个原因在于它可以使用在多种物理网络技术上,包括局域网和广域网技术,并能适应几乎所有的底层通信技术.20世纪80年代初,先在X.25上运行TCP/IP协议,而后,又在一个拨号语音网络(例如电话系统)上使用TCP/IP协议,又有TCP/IP在令牌环网上运行成功,最后,又实现了TCP/IP远程分组无线网点与其他Intemet网点之间进行TCP/IP的通信.

  3. Study of dynamical properties in β-Tcp/Ch layers

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A.; Caicedo, J. C. [Universidad del Valle, Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Cali, Valle del Cauca (Colombia); Aperador, W., E-mail: jacaicedoangulo1@gmail.com [Universidad Militar Nueva Granada, Departamento de Ingenieria, 80 Entrada A La KR11 No. 101, Bogota (Colombia)

    2015-07-01

    β-Tricalcium phosphate/Chitosan (β-Tcp/Ch) coatings were deposited on 316l stainless steel (316l Ss) substrates by a cathodic electrodeposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-ray diffraction, and the results indicated that the crystallographic structure of β-Tcp was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy and atomic force microscopy showed the root-mean squares hardness of the β-Tcp/Ch coatings decreased by further increasing chitosan percentage. The elastic-plastic characteristics of the coatings were determined by conducting nano indentation test, indicating that the increase if chitosan percentage is directly related to increasing the hardness and elastic modulus of the β-Tcp/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear the β-Tcp/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-Tcp/Ch coatings as a function of increasing of the chitosan percentage. (Author)

  4. Principle and prevention of TCP SYN Flood attack%TCP SYN Flood攻击的原理与防范

    Institute of Scientific and Technical Information of China (English)

    吴华光; 甘燕玲

    2005-01-01

    保证网络安全是网络技术正常发展和网络的正常运行的重要研究方向,通过讨论TCP三次握手的缺陷和TCP SYN Flood攻击的基本原理,探讨防御TCP SYN Flood攻击可以采取的措施.

  5. The Method of Winsock Network Program Based on TCP/IP Protocol%基于TCP/IP协议的WinSock网络程序方法

    Institute of Scientific and Technical Information of China (English)

    任泰明

    2002-01-01

    TCP/IP协议是Internet网络所使用的协议,设计基于TCP/IP的网络程序是Windows程序设计中难点,本文对基于TCP/IP协议的网络程序设计原理、方法和步骤进行了分析和说明.

  6. A Survey of TCP Reno, New Reno and Sack Over Mobile Ad-Hoc Network

    CERN Document Server

    Khan, Md Nazmul Islam; Aziz, Md Tariq

    2012-01-01

    Transmission Control Protocol (TCP) is often preferred to be implemented at the transport layer of a Mobile Ad-hoc Network (MANET) because of its wide range of applications, which enjoys the advantage of reliable data transmission in the Internet. However, because of some unique characteristics of MANET, TCP cannot offer reliable services while using e-mail, internet search and file transmission in such a network. The research investigates how well the different versions of TCP respond to various performance differentials when subjected to different network stresses and topology changes, aside from identifying the most efficient and robust TCP version(s) for different MANET scenarios. Among several TCP variants, three types are considered important for the analysis, namely TCP Reno, TCP New Reno and TCP Selective Acknowledgment (SACK). In most cases, the TCP performance is found in our study to decrease when the node size and mobility rate is increased in the network. There is, however, exception to this. As ...

  7. Effects of added ZnTCP on mechanical and biological properties of apatite cement

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, K.; Suzuki, K. [Okayama Univ. Dental School (Japan). Dept. of Biomaterials; Miyamoto, Y.; Toh, T.; Yuasa, T.; Nagayama, M. [Tokushima Univ. (Japan). First Dept. of Oral and Maxillofacial Surgery; Ito, A. [National Inst. for Advanced Interdisciplinary Research, MITT, Ibaragi (Japan)

    2001-07-01

    Effects of added Zn doped {beta}-tricalcium phosphate (ZnTCP) on mechanical and biological properties of apatite cement (AC) was studied. Powder X-ray diffractometer revealed that ZnTCP shows no reactivity with AC. The mechanical strength of AC decreased increasing amounts of added ZnTCP. We observed no effect on the setting time of AC when the amount of ZnTCP was 10% or less. Proliferation of the osteoblastic cells was significantly increased on the surface of AC containing 5% ZnTCP when compared with that containing no ZnTCP. In contrast, proliferation of the cells decreased on the surface of AC containing 10% ZnTCP when compared with that free from ZnTCP; indicating cytotoxity. We concluded therefore, that addition of ZnTCP to AC might be useful to enhance the osteoconductivity of AC when release of Zn{sup 2+} can be carefully regulated. (orig.)

  8. Characterizing End-to-End Delay Performance of Randomized TCP Using an Analytical Model

    Directory of Open Access Journals (Sweden)

    Mohammad Shorfuzzaman

    2016-03-01

    Full Text Available TCP (Transmission Control Protocol is the main transport protocol used in high speed network. In the OSI Model, TCP exists in the Transport Layer and it serves as a connection-oriented protocol which performs handshaking to create a connection. In addition, TCP provides end-to-end reliability. There are different standard variants of TCP (e.g. TCP Reno, TCP NewReno etc.which implement mechanisms to dynamically control the size of congestion window but they do not have any control on the sending time of successive packets. TCP pacing introduces the concept of controlling the packet sending time at TCP sources to reduce packet loss in a bursty traffic network. Randomized TCP is a new TCP pacing scheme which has shown better performance (considering throughput, fairness over other TCP variants in bursty networks. The end-to-end delay of Randomized TCP is a very important performance measure which has not yet been addressed. In the current high speed networks, it is increasingly important to have mechanisms that keep end-to-end to delay within an acceptable range. In this paper, we present the performance evaluation of end-to-end delay of Randomized TCP. To this end, we have used an analytical and a simulation model to characterize the end-to-end delay performance of Randomized TCP.

  9. Experimental Evaluation of TCP and ICMP in Network Measurement

    Institute of Scientific and Technical Information of China (English)

    LI Wen-wei; ZHANG Da-fang; XIE Gao-gang; YANG Jin-ming

    2005-01-01

    Network measurement is an important approach to understand network behaviors, which has been widely studied. Both Transfer Control Protocol (TCP) and Internet Control Messages Protocol (ICMP) are applied in network measurement, while investigating the differences between the measured results of these two protocols is an important topic that has been less investigated. In this paper, to compare the differences between TCP and ICMP when they are used in measuring host connectivity, RTT, and packet loss rate, two groups of comparison programs have been designed, and after careful evaluation of the program parameters, a lot of comparison experiments are executed on the Internet. The experimental results show that, there are significant differences between the host connectivity measured using TCP or ICMP; in general, the accuracy of connectivity measured using TCP is 20%- 30% higher than that measured using ICMP. The case of RTT and packet loss rate is complicated, which are related to path loads and destination host loads. While commonly, the RTT and packet loss rate measured using TCP or ICMP are very close. According to the experimental results, some advices are also given on protocol selection for conducting accurate connectivity, RTT and packet loss rate measurements.

  10. TCP-Adaptive in High Speed Long Distance Networks

    Directory of Open Access Journals (Sweden)

    Quan Liu

    2014-02-01

    Full Text Available With the development of high performance computing and increasing of network bandwidth, more and more applications require fast data transfer over high-speed long-distance networks. Research shows that the standard TCP Reno cannot fulfill the requirement of fast transfer of massive data due to its conservative congestion control mechanism. Some works have been proposed to improve the TCP throughput performance using more aggressive window increasing tactics and obtain substantial achievements. However, they cannot be strictly proved to be comprehensively suitable for high-speed complex network environments. In this paper, we propose TCP-Adaptive, an adaptive congestion control algorithm adjusting the increasing congestion window dynamically. The algorithm improves logarithmic detection procedure for available bandwidth in the flow path by distinguishing the first detection in congestion avoidance and retransmission timeout. On the other hand, an adaptive control algorithm is proposed to achieve better performance in high-speed long-distance networks. The algorithm uses round trip time (RTT variations to predict the congestion trends to update the increments of congestion window. Simulations verify the property of TCP-Adaptive and show satisfying performance in throughput, RTT fairness aspects over high-speed long-distance networks. Especially in sporadic loss environment, TCP-Adaptive shows a significant adaptability with the variations of link quality

  11. A Novel Congestion Detection Scheme in TCP Over OBS Networks

    KAUST Repository

    Shihada, Basem

    2009-02-01

    This paper introduces a novel congestion detection scheme for high-bandwidth TCP flows over optical burst switching (OBS) networks, called statistical additive increase multiplicative decrease (SAIMD). SAIMD maintains and analyzes a number of previous round-trip time (RTTs) at the TCP senders in order to identify the confidence with which a packet loss event is due to network congestion. The confidence is derived by positioning short-term RTT in the spectrum of long-term historical RTTs. The derived confidence corresponding to the packet loss is then taken in the developed policy for TCP congestion window adjustment. We will show through extensive simulation that the proposed scheme can effectively solve the false congestion detection problem and significantly outperform the conventional TCP counterparts without losing fairness. The advantages gained in our scheme are at the expense of introducing more overhead in the SAIMD TCP senders. Based on the proposed congestion control algorithm, a throughput model is formulated, and is further verified by simulation results.

  12. Research on TCP/IP computer network congestion control%对TCP/IP计算机网络拥塞控制的研究

    Institute of Scientific and Technical Information of China (English)

    余学杰

    2014-01-01

    为提升计算机的网络性能,更好地避免拥塞现象的发生,需要对其进行必要的技术控制。鉴于此,对基于TCP/IP协议的网络拥塞控制方法进行分析。在TCP拥塞控制中主要采用TCP Tahoe,TCP Reno,TCP New Reno以及TCP Sack四种方法,其中TCP New Reno对快速恢复算法进行了改进,通过对TCP协议中的Reno进行可视化处理,实行对网络拥塞的有效管理。而IP拥塞控制方法则分为FIFO,FQ和WFQ,RED以及ECN四种类型,通过队列调度管理方式实现了对网络拥塞的有效管理。%To enhance the performance of the computer network and avoid the occurrence of the congestion phenomenon,it is necessary to carry out the effective technical control. In view of this,the network congestion control methods based on TCP/IP protocol are analyzed. Four methods of TCP Tahoe,TCP Reno,TCP New Reno and TCP Sack are used for TCP congestion control;in which fast recovery algorithm was improved by means of TCP New Reno. The visualization processing can be per-formed through the Reno in TCP protocol to implement the effective management of network congestion. The IP congestion con-trol method can be divided into FIFO,FQ/WFQ,RED and ECN to realize the effective management of network congestion by queue scheduling management pattern.

  13. El alba-tcp mirado con buenos ojos

    Directory of Open Access Journals (Sweden)

    Christopher David Absell

    2012-01-01

    Full Text Available El surgimiento de la Alianza Bolivariana para los Pueblos de Nuestra América-Tratado de Comercio de los Pueblos (alba-tcp representa una novedad de importancia regional e internacional; sin embargo hasta la fecha el trabajo académico sobre la organización ha sido escaso y se ha caracterizado por tener un enfoque metodológico descriptivo carente de investigación empírica comprensiva. En este artículo sostengo que este enfoque metodológico ha imbuido la literatura de un sesgo positivo a favor del alba-tcp y sus proyectos de desarrollo. El objetivo de este artículo es examinar esta literatura para determinar una agenda de investigación para el estudio del alba-tcp.

  14. CW-HSTCP: Fair TCP in high-speed networks

    Institute of Scientific and Technical Information of China (English)

    PAN Xue-zeng; SU Fan-jun; L(U) Yong; PING Ling-di

    2006-01-01

    The congestion control mechanisms of the current standard TCP constrain the congestion windows that can be achieved by TCP in high-speed networks, which leads to low link utilization. HSTCP is one solution to solve this problem by modifying the congestion control mechanism to have the characteristics of TCP friendliness in high loss rate environment and high scalability in low loss rate environment. However, experiments revealed that HSTCP has severe RTT unfairness. After analyzing the RTT unfairness in HSTCP with a model, we proposed CW-HSTCP, which added a fair factor to decrease the difference of congestion window caused by different RTT. Fair factor of long RTT flows can cause a sharp window increment that is easy to cause a bursty traffic, so a method called block-pacing was adopted. Simulation results showed that our new proposal could alleviate the RTT unfairness while keeping advantages of HSTCP.

  15. Cloning, expression and alternative splicing of the novel isoform of hTCP11 gene

    DEFF Research Database (Denmark)

    Ma, Yong-xin; Zhang, Si-zhong; Wu, Qia-qing;

    2003-01-01

    To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing.......To identify a novel isoform of hTCP11 gene and investigate its expression and alternative splicing....

  16. A simulation-based study of HighSpeed TCP and its deployment

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Evandro de

    2003-04-29

    The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP's congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions including different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.

  17. A simulation-based study of HighSpeed TCP and its deployment

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Evandro de [Univ. of California, Berkeley, CA (United States)

    2003-05-01

    The current congestion control mechanism used in TCP has difficulty reaching full utilization on high speed links, particularly on wide-area connections. For example, the packet drop rate needed to fill a Gigabit pipe using the present TCP protocol is below the currently achievable fiber optic error rates. HighSpeed TCP was recently proposed as a modification of TCP's congestion control mechanism to allow it to achieve reasonable performance in high speed wide-area links. In this research, simulation results showing the performance of HighSpeed TCP and the impact of its use on the present implementation of TCP are presented. Network conditions including different degrees of congestion, different levels of loss rate, different degrees of bursty traffic and two distinct router queue management policies were simulated. The performance and fairness of HighSpeed TCP were compared to the existing TCP and solutions for bulk-data transfer using parallel streams.

  18. TCP-Call Admission Control Interaction in Multiplatform Space Architectures

    Directory of Open Access Journals (Sweden)

    Georgios Theodoridis

    2007-06-01

    Full Text Available The implementation of efficient call admission control (CAC algorithms is useful to prevent congestion and guarantee target quality of service (QoS. When TCP protocol is adopted, some inefficiencies can arise due to the peculiar evolution of the congestion window. The development of cross-layer techniques can greatly help to improve efficiency and flexibility for wireless networks. In this frame, the present paper addresses the introduction of TCP feedback into the CAC procedures in different nonterrestrial wireless architectures. CAC performance improvement is shown for different space-based architectures, including both satellites and high altitude platform (HAP systems.

  19. Analogues between tuning TCP for Data Acquisition and Datacenter Networks

    CERN Document Server

    Jereczek, Grzegorz Edmund; The ATLAS collaboration

    2015-01-01

    A many-to-one communication pattern is present both in Data Acquisition (DAQ) and datacenter networks. The problem arising from this pattern is widely known in the literature as incast and can be observed as TCP throughput collapse. It is a result of overloading the switch buffers, when a specific node in a network requests data from multiple sources. This paper provides two contributions. First, we confirm that there are strong analogies between the TCP behavior in DAQ and datacenter networks. Second, we evaluate different proposals from datacenter for application in DAQ to improve performance and reduce buffer requirements.

  20. Nova in Ophiuchus - TCP J17394608-2457555

    Science.gov (United States)

    Waagen, Elizabeth O.

    2017-05-01

    AAVSO Alert Notice 576 announces the discovery of a galactic nova in Ophiuchus, TCP J17394608-2457555, by Koichi Itagaki (Yamagata, Japan) at unfiltered CCD magnitude 13.6 on 2017 May 08.7511 UT. Spectroscopy indicating that TCP J17394608-2457555 is an FeII nova (highly reddened) was obtained 2017 May 11.15 UT by S. C. Wiliams (Lancaster) and M. J. Darnley (LJMU) (ATel #10366). Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details.

  1. Analogues between tuning TCP for Data Acquisition and Datacenter Networks

    CERN Document Server

    Jereczek, G; Malone, D

    2015-01-01

    A many-to-one communication pattern is present both in Data Acquisition (DAQ) and datacenter networks. The problem arising from this pattern is widely known in the literature as incast and can be observed as TCP throughput collapse. It is a result of overloading the switch buffers, when a specific node in a network requests data from multiple sources. This paper provides two contributions. First, we confirm that there are strong analogies between the TCP behavior in DAQ and datacenter networks. Second, we evaluate different proposals from datacenter for application in DAQ to improve performance and reduce buffer requirements.

  2. BIFURCATIONS AND CHAOS CONTROL IN TCP-RED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Internet is heterogeneous in nature,and ex-tremely wide variations in parametric perturbationlead to a very rich world of dynamical behaviorsranging from s mooth,stable operation to rathercomplicated irregular patterns.In[1],the occur-rence of chaotic behavior in TCP has been reportedfor the first ti me.Since the seminal work of Mathisand Floyd[2-3],there have been increasing interestsin the dynamical characteristics of Internet.In theprevious work,TCP congestion control algorithmplus RED queue management m...

  3. Internetworking with Internet Protocol (IP) and Transmission Control Protocol (TCP) within the Military

    OpenAIRE

    Eikenberg, Bruce R.

    1990-01-01

    Approved for public release; distribution is unlimited. The backbone of the internetworking technology widely used by the military, as well as many civilian installations, is commonly referred to as TCP/IP. Transmission Control Protocol (TCP) and Internet Protocol (IP) are the two standard communication protocols from which TCP/IP receives its name. By utilizing TCP/IP, the majority of technical issues of interconnecting various computer technologies have become transparent to the user. Th...

  4. Joint CARE-ELAN, CARE-HHH-APD, and EUROTEV-WP3 Workshop on Electron Cloud Clearing

    CERN Document Server

    Scandale, Walter; Schulte, D; Zimmermann, F; Electron Cloud Effects and Technological Consequences; ECL2

    2007-01-01

    This report contains the Proceedings of the joint CARE-HHH-APD, CARE-ELAN, and EUROTEV-WP3 Mini-Workshop on 'Electron Cloud Clearing - Electron Cloud and Technical Consequences', "ECL2", held at CERN in Geneva, Switzerland, 1-2 March 2007). The ECL2 workshop explored novel technological remedies against electron-cloud formation in an accelerator beam pipe. A primary motivation for the workshop was the expected harmful electron-cloud effects in the upgraded LHC injectors and in future linear colliders, as well as recent beam observations in operating facilities like ANKA, CESR, KEKB, RHIC, and SPS. The solutions discussed at ECL2 included enamel-based clearing electrodes, slotted vacuum chambers, NEG coating, and grooves. Several of the proposed cures were assessed in terms of their clearing efficiency and the associated beam impedance. The workshop also reviewed new simulation tools like the 3D electron-ion build-up 'Faktor', modeling assumptions, analytical calculations, beam experiments, and laboratory meas...

  5. Summary of the Mini BNL/LARP/CARE-HHH Workshop on Crab Cavities for the LHC (LHC-CC08)

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi,I.; Calaga, R.; Zimmermann, F.

    2008-05-01

    The first mini-workshop on crab compensation for the LHC luminosity upgrade (LHC-CC08) was held February 24-25, 2008 at the Brookhaven National Laboratory. A total of 35 participants from 3 continents and 15 institutions from around the world participated to discuss the exciting prospect of a crab scheme for the LHC. If realized it will be the first demonstration in hadron colliders. The workshop is organized by joint collaboration of BNL, US-LARP and CARE-HHH. The enormous interest in the subject of crab cavities for the international linear collider and future light sources has resulted in a large international collaboration to exchange aspects of synergy and expertise. A central repository for this exchange of information documenting the latest design effort for LHC crab cavities is consolidated in a wiki page: https://twiki.cern.ch/twiki/bin/view/Main/LHCCrabCavities. The main goal of this workshop was to define a road-map for a prototype crab cavity to be installed in the LHC and to discuss the associated R&D and beam dynamics challenges. The diverse subject of implementing the crab scheme resulted in a scientific program with a wide range of subtopics which were divided into 8 sessions. Each session was given a list of fundamental questions to be addressed and used as a guideline to steer the discussions.

  6. CARE-HHH-APD Workshop on Finalizing the Roadmap for the Upgrade of the CERN and GSI Accelerator Complex

    CERN Document Server

    Zimmermann, Frank; BEAM'07; BEAM 2007; Finalizing the Roadmap for the Upgrade of the LHC and GSI Accelerator Complex

    2008-01-01

    This report contains the Proceedings of the CARE-HHH-APD Event BEAM’07, “Finalizing the Roadmap for the Upgrade of the CERN & GSI Accelerator Complex,” which was held at CERN in Geneva, Switzerland, from 1 to 5 October 2007. BEAM’07 was primarily devoted to beam dynamics limitations for the two, or three, alternative baseline scenarios of the LHC luminosity upgrade and to critical design choices for the upgrade of the LHC injector complex at CERN and for the FAIR complex at GSI. It comprised five parts: (1) a Mini-Workshop on LHC+ Beam Performance, (2) a CERN-GSI Meeting on Collective Effects, (3) the Francesco Ruggiero Memorial Symposium, (4) a Mini-Workshop on the LHC Injectors Upgrade, and (5) the BEAM’07 Summaries. Topics addressed in the first mini-workshop of BEAM’07 ranged from the luminosity performance reach of the upgraded LHC in different scenarios, over the generation and stability of the future LHC beams, the turnaround time, beam–beam effects, luminosity levelling methods, and ...

  7. CARE-HHH-APD Workshop on Interaction Regions for the LHC Upgrade, DAFNE, and SuperB

    CERN Document Server

    Zimmermann, Frank; IR'07; IR 2007

    2008-01-01

    This report contains the Proceedings of the CARE-HHH-APD Mini-Workshop “IR’07,” which was held in Frascati, Italy, from 7 to 9 November 2007. The central theme of the IR’07 Mini-Workshop was the upgrade of the LHC interaction region (IR). A second topic was the experience with the upgraded DAFNE IR as well as the ongoing plans and studies for SuperB, plus possible applications of crab-waist collisions for the LHC upgrade. Discussions during the workshop addressed the performance and limitations of the IR-upgrade optics performance, the optimization of new LHC triplet magnets, the US-LARP magnet strategy (response to Lucio Rossi’s “challenge”), heat deposition, earlyseparation dipoles, detector-integrated quadrupoles, strategy for crab cavities, beam–beam wire compensators, and crab-waist collisions. At IR’07 all auxiliary systems, e.g. wires and crab cavities, received a strong boost. Energy deposition was shown to add an important criterion to the optics requirements—in a first attempt a ...

  8. Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH)-syndrome. Ultrastructural changes of mitochondria in cultured dermal fibroblasts of three patients.

    Science.gov (United States)

    Haust, M D; Dewar, R A; Gatfield, D P; Gordon, B A

    1996-03-01

    Mitochondria of fibroblasts cultured from the skin obtained at biopsy from three patients with the hyperornithinemia-hyperammonemia-homocitrullinuria (HHH)-syndrome, one of the autosomal recessive, heritable urea cycle disorders, were studied with appropriate controls ultrastructurally. The patients were two severely retarded 10- and 12-year-old boys, and a 22-year-old sister of the former whose mental status was at the low normal range; she never had motor impairments or seizures. The mitochondria, similar in all three patients, were increased in number, very long, branching and/or "looping," and tortuous. "Spurs" or "buddings" extended from their lateral surfaces and the terminal segments were often bulbous. Other unusual configurations were also present. In addition, giant forms with large diameter contained innumerable closely-packed and parallel cristae which traversed the entire width of these mitochondria; at times they assumed a "whirled" pattern. The mitochondrial matrix was usually of high electron density. These changes were not a feature of fibroblastic mitochondria of controls. Several changes resembled those of hepatic mitochondria in this disorder. All features are interpreted as an attempt at expanding the mitochondrial volume (via structural substratum) to compensate for the metabolic incompetence of these organelles (a block in transmembranous transfer of ornithine from hyaloplasm into mitochondria for conversion to citrulline).

  9. Long-term monitoring of sleep apnea at home in heart failure patients: preliminary results from the HHH study.

    Science.gov (United States)

    Pinna, G D; Maestri, R; Gobbi, E; Capomolla, S; Campana, C; Emdin, M; Di Lenarda, A; La Rovere, M T; Andrews, D; Johnson, P; Mortara, A; Sleight, P

    2004-01-01

    Sleep apnea is very common in patients with chronic heart failure (CHF) and has important implications in terms of morbidity, mortality and clinical management. Home respiratory telemonitoring might constitute a potential low-cost, widely-applicable alternative to traditional polysomnography in the evaluation and long-term monitoring of breathing disorders in these patients. In this paper we briefly describe the technological infrastructure and present preliminary results of the European Community multicountry trial HHH (Home or Hospital in Heart Failure), which is currently testing a novel system for home telemonitoring of cardiorespiratory signals in CHF patients. The recording and transmitting devices are suitable to be self-managed by the patient. We give a detailed report on the prevalence of nocturnal respiratory disorders at the beginning of the one-year follow-up and on their persistency over the following recordings (one per month). These preliminary findings clearly indicate that intermittent home telemonitoring of respiratory signals based on patient's self-management is feasible in CHF patients and the compliance is high. Reported statistics unambiguously confirm the high prevalence of nocturnal breathing disorders in these patients and clearly show that this phenomenon tends to persist over time.

  10. File list: Oth.Epd.20.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.20.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX019786,SRX663250,SRX6...X514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.20.TCP1.AllCell.bed ...

  11. File list: Oth.ALL.05.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663251,SRX663249...44,SRX663252,SRX105186,SRX514838,SRX018991,SRX277138,SRX105187,SRX277132,SRX099055 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.05.TCP1.AllCell.bed ...

  12. File list: Oth.Epd.10.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.10.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663251,SRX019786,SRX5...X105186,SRX514839,SRX514838,SRX099053 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.10.TCP1.AllCell.bed ...

  13. File list: Oth.ALL.20.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.20.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX019786,SRX663250...39,SRX514843,SRX018991,SRX277132,SRX212375,SRX514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.20.TCP1.AllCell.bed ...

  14. File list: Oth.Epd.50.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.50.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663250,SRX663252,SRX6...X514838,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.50.TCP1.AllCell.bed ...

  15. File list: Oth.ALL.50.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663250,SRX663252...43,SRX018992,SRX212375,SRX514838,SRX277135,SRX277132,SRX099053,SRX099055,SRX514844 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.50.TCP1.AllCell.bed ...

  16. File list: Oth.Epd.05.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Epd.05.TCP1.AllCell hg19 TFs and others TCP1 Epidermis SRX663251,SRX663249,SRX6...X514838,SRX018991,SRX105187,SRX099055 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Epd.05.TCP1.AllCell.bed ...

  17. File list: Oth.ALL.10.TCP1.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.10.TCP1.AllCell hg19 TFs and others TCP1 All cell types SRX663251,SRX019786...38,SRX277135,SRX018991,SRX105187,SRX099055,SRX105186,SRX514839,SRX514838,SRX099053 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.ALL.10.TCP1.AllCell.bed ...

  18. A Survey Of Tcp Reno, New Reno And Sack Over Mobile Ad-Hoc Network

    Directory of Open Access Journals (Sweden)

    Md Nazmul Islam Khan

    2012-02-01

    Full Text Available Transmission Control Protocol (TCP is often preferred to be implemented at the transport layer of a Mobile Ad-hoc Network (MANET because of its wide range of applications, which enjoys the advantage of reliable data transmission in the Internet. However, because of some unique characteristics of MANET, TCP cannot offer reliable services while using e-mail, internet search and file transmission insuch a network. The research investigates how well the different versions of TCP respond to various performance differentials when subjected to different network stresses and topology changes, aside from identifying the most efficient and robust TCP version(s for different MANET scenarios. Among several TCP variants, three types are considered important for the analysis, namely TCP Reno, TCP New Reno and TCP Selective Acknowledgment (SACK. In most cases, the TCP performance is found in our study to decrease when the node size and mobility rate is increased in the network. There is, however, exception to this. As our simulation results demonstrate, the increases in the node velocity sometimes help the TCP to attain a better performance. The study also reveals that out of the three variants, TCP SACK can adaptrelatively well to the changing network sizes while TCP Reno performs most robustly in the presence ofdifferent mobility rates within MANET.

  19. TCP-HY: Improving TCP Performance in Hybrid IP Network%TCP-HY:优化TCP在混合IP网络环境中的效率

    Institute of Scientific and Technical Information of China (English)

    徐航宇; 罗键

    2007-01-01

    在混合网络环境下,由于数据包传输的非时序性以及在传输过程中相对较高的误码率,TCP的传输效率极大地被降低了.对此,提出了一种新的TCP改进版本:TCP-HY,它能够有效解决数据包延迟以及高误码率的问题.试验表明,TCP-HY在混合网络环境中能够大大提高TCP的效率,充分利用有效带宽,是一种优秀的解决方案.

  20. Versatile Markovian models for networks with asymmetric TCP sources

    NARCIS (Netherlands)

    Foreest, van N.D.; Haverkort, B.R.; Mandjes, M.R.H.; Scheinhardt, W.R.W.

    2004-01-01

    In this paper we use Stochastic Petri Nets (SPNs) to study the interaction of multiple TCP sources that share one or two buffers, thereby considerably extending earlier work. We first consider two sources sharing a buffer and investigate the consequences of two popular assumptions for the loss proce

  1. Versatile Stochastic Models for Networks with Asymmetric TCP Sources

    NARCIS (Netherlands)

    Foreest, van Nicky D.; Haverkort, Boudewijn R.; Mandjes, Michel R.H.; Scheinhardt, Werner R.W.

    2007-01-01

    In this paper we use stochastic Petri nets (SPNs) to study the interaction of multiple TCP sources that share one or two buffers. No analytical nor numerical results have been presented for such cases yet. We use SPNs in an unconventional way: the tokens in the SPN do not represent the packets being

  2. SCPS-TP: A Satellite-Enhanced TCP

    Science.gov (United States)

    Scott, Keith; Torgerson, Leigh

    2004-01-01

    This viewgraph presentation reviews the Space Communications Protocol Standard Transport Protocol (SCPS-TP) which is a satellite enhanced Transport Control Protocol (TCP). The contents include: 1) Purpose; 2) Background; 3) Stressed Communication Environments; 4) SCPS-TP Features; 5) SCPS-TP Performance; 6) Performance Enhancing Proxies (PEPs); and 7) Ongoing and Future SCPS-TP Work.

  3. Ohio Medical Office Management. Technical Competency Profile (TCP).

    Science.gov (United States)

    Ray, Gayl M.; Wilson, Nick; Mangini, Rick

    This document provides a framework for a broad-based secondary and postsecondary curriculum to prepare students for employment in medical office management. The first part of the technical competency profile (TCP) contains the following items: an explanation of the purpose and scope of Ohio's TCPs; college tech prep program standards; an overview…

  4. Ohio Marketing Management and Research. Technical Competency Profile (TCP).

    Science.gov (United States)

    Ray, Gayl M.; Wilson, Nick; Mangini, Rick

    This document provides a framework for a broad-based secondary and postsecondary curriculum to prepare students for employment in marketing management and research (MMR). The first part of the technical competency profile (TCP) contains the following items: an explanation of the purpose and scope of Ohio's TCPs; college tech prep program…

  5. TCP-IP Model in Data Communication and Networking

    Directory of Open Access Journals (Sweden)

    Pranab Bandhu Nath

    2015-10-01

    Full Text Available The Internet protocol suite is the computer networking model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP, because it’s most important protocols, the Transmission Control Protocol (TCP and the Internet Protocol (IP, were the first networking protocols defined in this standard. Often also called the Internet model, it was originally also known as the DoD model, because the development of the networking model was funded by DARPA, an agency of the United States Department of Defense. TCP/IP provides end-to-end connectivity specifying how data should be packetized, addressed, transmitted, routed and received at the destination. This functionality is organized into four abstraction layers which are used to sort all related protocols according to the scope of networking involved. From lowest to highest, the layers are the link layer, containing communication technologies for a single network segment (link; the internet layer, connecting hosts across independent networks, thus establishing internetworking; the transport layer handling host-to-host communication; and the application layer, which provides process-to-process application data exchange. Our aim is describe operation & models of TCP-IP suite in data communication networking

  6. Construction of a nuclear data server using TCP/IP

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko; Sakai, Osamu [Kyushu Univ., Fukuoka (Japan)

    1997-03-01

    We construct a nuclear data server which provides data in the evaluated nuclear data library through the network by means of TCP/IP. The client is not necessarily a user but a computer program. Two examples with a prototype server program are demonstrated, the first is data transfer from the server to a user, and the second is to a computer program. (author)

  7. Displaying digital video over ethernet TCP-IP

    Science.gov (United States)

    Foster, John; Jackson, Paul

    1994-04-01

    Transmission and playback of digital audio and video via TCP/IP has been successfully completed with the use of typical low-end UNIX workstations. In addition, attempts have been made to increase the frame rate by sending only sections of a frame that varied the most.

  8. Mitigating TCP Degradation over Intermittent Link Failures using Intermediate Buffers

    Science.gov (United States)

    2006-06-01

    buffering strategy, retransmission strategy, TCP state management, intermediate ac- knowledgment, custody considerations, and leader election considerations...availability are all ripe for research in strategic buffering. One final custodial area open for pursuit is a leader election protocol. Along a route with

  9. 未来高带宽网络中FAST TCP与TCP Vegas的公平性分析%Fairness analysis of FAST TCP and TCP Vegas over future high-bandwidth internet

    Institute of Scientific and Technical Information of China (English)

    朱小松

    2012-01-01

    FAST TCP, a modern end-to-end protocol adopting queuing delay as a congestion measure. However, the lack of a precise measurement of queuing delay leads to a potential unfairness problem that FAST TCP flows may be discriminated against according to their starting times in a persistent congestion scenario, TCP Vegas also encounters the unfairness problem. The unfairness problem is quantitatively assessed by mathematical analysis and ns2 simulations, then, we compared FAST TCP with TCP Vegas. Consequently, FAST TCP demonstrates a competitive edge over TCP Vegas, under future high bandwidth-delay product environment. This conclusion will contribute to the improvement of FAST TCP for future reference.%FAST TCP是先进的端到端拥塞控制协议,采用队列时延作为拥塞度量.由于不能准确测得精确的队列时延,此协议中存有不公平的隐患,即在某些持续拥塞场景下,不同时刻启动的FAST TCP流会受到差别对待,TCP Vegas中同样存在不公平问题.通过数学分析和ns2仿真对这种不公平问题进行量化,进而比较FASTTCP与TCP Vegas在公平性问题上的性能差异.结果证明了在将来高带宽时延乘积网络环境下,FAST TCP在公平性上要明显优于TCP Vegas.这为对FAST TCP协议的改进给出了有价值的参照.

  10. Evolution and Expression Patterns of TCP Genes in Asparagales

    Science.gov (United States)

    Madrigal, Yesenia; Alzate, Juan F.; Pabón-Mora, Natalia

    2017-01-01

    CYCLOIDEA-like genes are involved in the symmetry gene network, limiting cell proliferation in the dorsal regions of bilateral flowers in core eudicots. CYC-like and closely related TCP genes (acronym for TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATION CELL FACTOR) have been poorly studied in Asparagales, the largest order of monocots that includes both bilateral flowers in Orchidaceae (ca. 25.000 spp) and radially symmetrical flowers in Hypoxidaceae (ca. 200 spp). With the aim of assessing TCP gene evolution in the Asparagales, we isolated TCP-like genes from publicly available databases and our own transcriptomes of Cattleya trianae (Orchidaceae) and Hypoxis decumbens (Hypoxidaceae). Our matrix contains 452 sequences representing the three major clades of TCP genes. Besides the previously identified CYC specific core eudicot duplications, our ML phylogenetic analyses recovered an early CIN-like duplication predating all angiosperms, two CIN-like Asparagales-specific duplications and a duplication prior to the diversification of Orchidoideae and Epidendroideae. In addition, we provide evidence of at least three duplications of PCF-like genes in Asparagales. While CIN-like and PCF-like genes have multiplied in Asparagales, likely enhancing the genetic network for cell proliferation, CYC-like genes remain as single, shorter copies with low expression. Homogeneous expression of CYC-like genes in the labellum as well as the lateral petals suggests little contribution to the bilateral perianth in C. trianae. CIN-like and PCF-like gene expression suggests conserved roles in cell proliferation in leaves, sepals and petals, carpels, ovules and fruits in Asparagales by comparison with previously reported functions in core eudicots and monocots. This is the first large scale analysis of TCP-like genes in Asparagales that will serve as a platform for in-depth functional studies in emerging model monocots. PMID:28144250

  11. Evolution and Expression Patterns of TCP Genes in Asparagales.

    Science.gov (United States)

    Madrigal, Yesenia; Alzate, Juan F; Pabón-Mora, Natalia

    2017-01-01

    CYCLOIDEA-like genes are involved in the symmetry gene network, limiting cell proliferation in the dorsal regions of bilateral flowers in core eudicots. CYC-like and closely related TCP genes (acronym for TEOSINTE BRANCHED1, CYCLOIDEA, and PROLIFERATION CELL FACTOR) have been poorly studied in Asparagales, the largest order of monocots that includes both bilateral flowers in Orchidaceae (ca. 25.000 spp) and radially symmetrical flowers in Hypoxidaceae (ca. 200 spp). With the aim of assessing TCP gene evolution in the Asparagales, we isolated TCP-like genes from publicly available databases and our own transcriptomes of Cattleya trianae (Orchidaceae) and Hypoxis decumbens (Hypoxidaceae). Our matrix contains 452 sequences representing the three major clades of TCP genes. Besides the previously identified CYC specific core eudicot duplications, our ML phylogenetic analyses recovered an early CIN-like duplication predating all angiosperms, two CIN-like Asparagales-specific duplications and a duplication prior to the diversification of Orchidoideae and Epidendroideae. In addition, we provide evidence of at least three duplications of PCF-like genes in Asparagales. While CIN-like and PCF-like genes have multiplied in Asparagales, likely enhancing the genetic network for cell proliferation, CYC-like genes remain as single, shorter copies with low expression. Homogeneous expression of CYC-like genes in the labellum as well as the lateral petals suggests little contribution to the bilateral perianth in C. trianae. CIN-like and PCF-like gene expression suggests conserved roles in cell proliferation in leaves, sepals and petals, carpels, ovules and fruits in Asparagales by comparison with previously reported functions in core eudicots and monocots. This is the first large scale analysis of TCP-like genes in Asparagales that will serve as a platform for in-depth functional studies in emerging model monocots.

  12. A New Analytical Model for TCP Reno with Bursts Error Considered

    Institute of Scientific and Technical Information of China (English)

    DENG Jian-min; JI Hong; YUE Guang-xin; YIN Chang-chuan

    2003-01-01

    In this paper, we present a new analytical model for TCP Reno, and this method can also be used in other versions of TCP. The first order two-state Markovian model is used to describe the wireless link, so as to deal with the burst error in wireless links very well. The tineout mechanism of TCP is also considered and a geometric method describes the erponential growth of TCP timeout . Also this method is effective for the study of the growth of TCP transmission window. Analytical results indicate that this model is effective.

  13. Investigation of TCP Veno Performance over Wirless Ad Hoc Network%TCP Veno在无线Ad Hoc网络中的性能分析

    Institute of Scientific and Technical Information of China (English)

    唐述; 谢显中; 赵锐

    2007-01-01

    分析了TCP Veno在无线Ad Hoc这样的多跳的网络中的性能,并分SANET(静态无线多跳网络)和MANET(移动无线多跳网络)两种网络环境进行仿真分析,结果显示TCP Veno的性能较TCP Reno有一定程度的改进,但并没有在无线单跳网络中的性能优势出色,这对实际应用TCP Veno很重要.

  14. 使用Sniffer软件透视TCP/IP协议的安全%To Analyze the Security of TCP/IP Protocol Using Sniffer Software

    Institute of Scientific and Technical Information of China (English)

    张保江

    2014-01-01

    TCP/IP协议是当前计算机局域网和Internet普遍使用的组网协议,该文结合TCP/IP的一个通信实例,使用Sniffer软件,截取并分析其通信数据,得出TCP/IP协议缺乏相应的安全机制的结论,并在此基础上,讨论了基于TCP/IP协议的有关安全的常用做法。%TCP/IP is the protocol that commonly used to build the Ethernet or Internet. Based on an instance of TCP/IP com-munication, the thesis uses the sniffer software to capture and analyze the data of TCP/IP communications and draws the conclu-sion that TCP/IP protocol has no measures to ensure the security of the communications. At last the thesis introduces some ways to ensure the security of TCP/IP communications.

  15. VB客户——服务器(TCP/IP)编程%Using VB Design Client-Server(TCP/IP) Network Program

    Institute of Scientific and Technical Information of China (English)

    陶运道

    2002-01-01

    利用VB的 WinSock 控件可以与远程计算机建立连接,并通过用户数据文报协议(UDP)或者传输控制协议(TCP)进行数据交换.TCP/IP协议是Internet最重要的协议.VB提供了WinSock控件,用于在TCP/IP的基础上进行网络通信.本文介绍如何用VB来实现TCP/IP网络编程.

  16. Controlled release of NELL-1 protein from chitosan/hydroxyapatite-modified TCP particles.

    Science.gov (United States)

    Zhang, Yulong; Dong, Rui; Park, Yujin; Bohner, Marc; Zhang, Xinli; Ting, Kang; Soo, Chia; Wu, Benjamin M

    2016-09-10

    NEL-like molecule-1 (NELL-1) is a novel osteogenic protein that showing high specificity to osteochondral cells. It was widely used in bone regeneration research by loading onto carriers such as tricalcium phosphate (TCP) particles. However, there has been little research on protein controlled release from this material and its potential application. In this study, TCP was first modified with a hydroxyapatite coating followed by a chitosan coating to prepare chitosan/hydroxyapatite-coated TCP particles (Chi/HA-TCP). The preparation was characterized by SEM, EDX, FTIR, XRD, FM and Zeta potential measurements. The NELL-1 loaded Chi/HA-TCP particles and the release kinetics were investigated in vitro. It was observed that the Chi/HA-TCP particles prepared with the 0.3% (wt/wt) chitosan solution were able to successfully control the release of NELL-1 and maintain a slow, steady release for up to 28 days. Furthermore, more than 78% of the loaded protein's bioactivity was preserved in Chi/HA-TCP particles over the period of the investigation, which was significantly higher than that of the protein released from hydroxyapatite coated TCP (HA-TCP) particles. Collectively, this study suggests that the osteogenic protein NELL-1 showed a sustained release pattern after being encapsulated into the modified Chi/HA-TCP particles, and the NELL-1 integrated composite of Chi/HA-TCP showed a potential to function as a protein delivery carrier and as an improved bone matrix for use in bone regeneration research.

  17. Improving TCP Network Performance by Detecting and Reacting to Packet Reordering

    Science.gov (United States)

    Kruse, Hans; Ostermann, Shawn; Allman, Mark

    2003-01-01

    There are many factors governing the performance of TCP-basec applications traversing satellite channels. The end-to-end performance of TCP is known to be degraded by the reordering, delay, noise and asymmetry inherent in geosynchronous systems. This result has been largely based on experiments that evaluate the performance of TCP in single flow tests. While single flow tests are useful for deriving information on the theoretical behavior of TCP and allow for easy diagnosis of problems they do not represent a broad range of realistic situations and therefore cannot be used to authoritatively comment on performance issues. The experiments discussed in this report test TCP s performance in a more dynamic environment with competing traffic flows from hundreds of TCP connections running simultaneously across the satellite channel. Another aspect we investigate is TCP's reaction to bit errors on satellite channels. TCP interprets loss as a sign of network congestion. This causes TCP to reduce its transmission rate leading to reduced performance when loss is due to corruption. We allowed the bit error rate on our satellite channel to vary widely and tested the performance of TCP as a function of these bit error rates. Our results show that the average performance of TCP on satellite channels is good even under conditions of loss as high as bit error rates of 10(exp -5)

  18. Improvement of β-TCP/PLLA biodegradable material by surface modification with stearic acid.

    Science.gov (United States)

    Ma, Fengcang; Chen, Sai; Liu, Ping; Geng, Fang; Li, Wei; Liu, Xinkuan; He, Daihua; Pan, Deng

    2016-05-01

    Poly-L-lactide (PLLA) is a biodegradable polymer and used widely. Incorporation of beta tricalcium phosphate (β-TCP) into PLLA can enhance its osteoinductive properties. But the interfacial layer between β-TCP particles with PLLA matrix is easy to be destroyed due to inferior interfacial compatibility of the organic/inorganic material. In this work, a method of β-TCP surface modification with stearic acid was investigated to improve the β-TCP/PLLA biomaterial. The effects of surface modification on the β-TCP were investigated by FTIR, XPS, TGA and CA. It was found that the stearic acid reacted with β-TCP and oxhydryl was formed during the surface modification. Hydrophilicity of untreated or modified β-TCP/PLLA composite was increased by the addition of 10 wt.% β-TCP, but it decreased as the addition amount increased from 10 wt.% to 20 wt.%. Two models were suggested to describe the effect of β-TCP concentration on CA of the composites. Mechanical properties of β-TCP/PLLA composites were tested by bending and tensile tests. Fractures of the composites after mechanical test were observed by SEM. It was found that surface modification with stearic acid improved bending and tensile strengths of the β-TCP/PLLA composites obviously. The SEM results indicated that surface modification decreased the probability of interface debonding between fillers and matrix under load.

  19. 尼罗罗非鱼TCP-1-beta和TCP-1-eta的分子特征及其低温诱导表达%MOLECULAR CHARACTERIZATION AND INDUCTION EXPRESSION OF TCP-1-BETA AND TCP-1-ETA UNDER LOW TEMPERATURES IN TILAPIA OREOCHROMIS NILOTICUS

    Institute of Scientific and Technical Information of China (English)

    谢建丽; 林勇; 曾兰; 王忠卫; 桂建芳

    2012-01-01

    为了研究尼罗罗非鱼耐寒性状的分子基础并为耐寒品种选育提供参考,研究从尼罗罗非鱼中克隆了HSP60家族TCP-1-beta和TCP-1-eta基因并对其在低温诱导下的表达特征进行了分析.尼罗罗非鱼TCP-1-beta cDNA长度为1755 bp,包括1605 bp的完整开放阅读框,编码534个氨基酸;尼罗罗非鱼TCP-1-eta cDNA长度1651 bp,包括1638 bp的完整开放阅读框,编码545个氨基酸.与其他物种同源基因的蛋白序列比对结果显示,TCP-1-beta和TCP-1-eta蛋白在物种间同源性很高,且都具有保守的ATP结合结构域等,预示其在物种间功能的保守性.实时荧光定量PCR结果表明:TCP-1-beta和TCP-1-eta在各组织中呈遍在表达,但在肌肉中表达量最高;诱导温度从22℃降至12℃,不同低温诱导48h后TCP-1-beta和TCP-1-eta均呈上调表达,在18℃时表达开始上调,随着低温胁迫程度加强,表达上调幅度增大,至12℃时表达量达到最高,TCP-1-beta和TCP-1-eta上调幅度分别达到常温的12.2倍和10.7倍.这些结果预示在尼罗罗非鱼中,TCP-1-beta和TCP-1-eta是潜在的耐寒相关基因.%Nile tilapia (Oreochromis niloticus) is one of the commercially important fish species in the southern China, but the lack of cold-resistant strains in tilapia results in a large number of deaths in winter and early spring. Some heat-shock proteins (Hsps) have been revealed to facilitate correct folding of other proteins under diverse forms of physiological stresses, such as extreme temperatures, chemical toxicity and oxidative stress. To understand the molecular mechanism of cold tolerance in fish, we cloned the full-length cDNAs of TCP-1-beta and TCP-1-eta of the Hsp60 family in nile tilapia {Oreochromis niloticus), and studied their expression patterns under normal and low temperature treatments. The TCP-1-beta cDNA consisted of 1755 bp and encoded a peptide of 534 amino acids. The TCP-1-eta cDNA consisted of 1651 bp and encoded a peptide of 545

  20. 10~Gbps TCP/IP streams from the FPGA for High Energy Physics

    CERN Document Server

    Bauer, Gerry; Branson, James; Chaze, Olivier; Cittolin, Sergio; Coarasa Perez, Jose Antonio; Darlea, Georgiana Lavinia; Deldicque, Christian; Dobson, Marc; Dupont, Aymeric; Erhan, Samim; Gigi, Dominique; Glege, Frank; Gomez Ceballos, Guillelmo; Gomez-Reino Garrido, Robert; Hartl, Christian; Hegeman, Jeroen Guido; Holzner, Andre Georg; Masetti, Lorenzo; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; Nunez Barranco Fernandez, Carlos; O'Dell, Vivian; Orsini, Luciano; Ozga, Wojciech Andrzej; Paus, Christoph Maria Ernst; Petrucci, Andrea; Pieri, Marco; Racz, Attila; Raginel, Olivier; Sakulin, Hannes; Sani, Matteo; Schwick, Christoph; Spataru, Andrei Cristian; Stieger, Benjamin Bastian; Sumorok, Konstanty; Veverka, Jan; Wakefield, Christopher Colin; Zejdl, Petr

    2014-01-01

    The DAQ system of the CMS experiment at CERN collects data from more than 600 custom detector Front-End Drivers (FEDs). During 2013 and 2014 the CMS DAQ system will undergo a major upgrade to address the obsolescence of current hardware and the requirements posed by the upgrade of the LHC accelerator and various detector components. For a loss-less data collection from the FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. To limit the TCP hardware implementation complexity the DAQ group developed a simplified and unidirectional but RFC~793 compliant version of the TCP protocol. This allows to use a PC with the standard Linux TCP/IP stack as a receiver. We present the challenges and protocol modifications made to TCP in order to simplify its FPGA implementation. We also describe the interaction between the simplified TCP and Linux TCP/IP stack including the performance measurements.

  1. TCP Veno在无线AdHoc网络中的性能比较研究

    Institute of Scientific and Technical Information of China (English)

    唐述; 谢显中; 赵锐

    2007-01-01

    TCP Veno是一种新的无线网络环境下TCP的拥塞控制机制,它综合了TCP Reno和TCP Vegas的特点,对单跳无线网络的性能有了较大的改善。对TCP Veno应用于无线多跳网络中的性能进行研究,将TCP Veno在三种不同的无线AdHoc路由协议下的性能进行了仿真分析和比较,结果显示TCP Veno在不同的路由协议下的性能有所不同,通过比较,可以找到一个在无线AdHoc网络中更适合TCP Veno的路由协议。

  2. TCP transcription factors are critical for the coordinated regulation of isochorismate synthase 1 expression in Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Xiaoyan; Gao, Jiong; Zhu, Zheng; Dong, Xianxin; Wang, Xiaolei; Ren, Guodong; Zhou, Xin; Kuai, Benke

    2015-04-01

    Salicylic acid (SA) plays an important role in various aspects of plant development and responses to stresses. To elucidate the sophisticated regulatory mechanism of SA synthesis and signaling, we used a yeast one-hybrid system to screen for regulators of isochorismate synthase 1 (ICS1), a gene encoding the key enzyme in SA biosynthesis in Arabidopsis thaliana. A TCP family transcription factor AtTCP8 was initially identified as a candidate regulator of ICS1. The regulation of ICS1 by TCP proteins is supported by the presence of a typical TCP binding site in the ICS1 promoter. The binding of TCP8 to this site was confirmed by in vitro and in vivo assays. Expression patterns of TCP8 and its corresponding gene TCP9 largely overlapped with ICS1 under pathogen attack. A significant reduction in the expression of ICS1 during immune responses was observed in the tcp8 tcp9 double mutant. We also detected strong interactions between TCP8 and SAR deficient 1 (SARD1), WRKY family transcription factor 28 (WRKY28), NAC (NAM/ATAF1,ATAF2/CUC2) family transcription factor 019 (NAC019), as well as among TCP8, TCP9 and TCP20, suggesting a complex coordinated regulatory mechanism underlying ICS1 expression. Our results collectively demonstrate that TCP proteins are involved in the orchestrated regulation of ICS1 expression, with TCP8 and TCP9 being verified as major representatives.

  3. Epitaxial growth of magnetoresistive (00h), (0hh), and (hhh) La2/3Sr1/3MnO3 thin films on (001)Si substrates

    Science.gov (United States)

    Fontcuberta, J.; Bibes, M.; Martínez, B.; Trtik, V.; Ferrater, C.; Sánchez, F.; Varela, M.

    1999-03-01

    We show that suitable choice of the buffer heterostructure allows us to obtain epitaxial (00h), (0hh), and (hhh) La2/3Sr1/3MnO3 thin films on buffered Si(001) substrates. The magnetotransport properties are investigated. Irrespective of the film texture, it is found that the easy-magnetization direction lies within the film plane. The low-field magnetoresistance is mainly controlled by the in-plane misorientation of crystallites while differences associated with the distinct microstructure of the interfaces appear to have only a second-order effect.

  4. BIFURCATIONS AND CHAOS CONTROL IN TCP-RED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Liu Fang

    2006-01-01

    Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.

  5. Design of feedback controller for TCP/AQM networks

    Directory of Open Access Journals (Sweden)

    Sukant Kishoro Bisoy

    2017-02-01

    Full Text Available In this paper, we propose a novel proportional-differential-type feedback controller called Novel-PD as new active queue management (AQM to regulate the queue length with small oscillation. It measures the current queue length and uses the current queue length and differential error signals to adjust packet drop probability dynamically. We provide control theoretic analysis of system stability and develop guidelines to select control gain parameters of Novel-PD. The design of Novel-PD for TCP/AQM system is given in details. NS2 is used for conducting extensive simulation. The proposed controller is compared with random early detection (RED, random exponential marking (REM, proportional integrator (PI and proportional derivative (PD controller. Result shows that, Novel-PD is stable and achieves faster response in dynamic environments where number of TCP connections, bottleneck capacity, round trip time (RTT keeps changing. The proposed controller outperforms other AQM schemes.

  6. PERFORMANCE ANALYSIS OF MULTI-PATH TCP NETWORK

    Directory of Open Access Journals (Sweden)

    Hamzah M A Hijawi

    2016-03-01

    Full Text Available MPTCP is proposed by IETF working group, it allows a single TCP stream to be split across multiple paths. It has obvious benefits in performance and reliability. MPTCP has implemented in Linux-based distributions that can be compiled and installed to be used for both real and experimental scenarios. In this article, we provide performance analyses for MPTCP with a laptop connected to WiFi access point and 3G cellular network at the same time. We prove experimentally that MPTCP outperforms regular TCP for WiFi or 3G interfaces. We also compare four types of congestion control algorithms for MPTCP that are also implemented in the Linux Kernel. Results show that Alias Linked Increase Congestion Control algorithm outperforms the others in the normal traffic load while Balanced Linked Adaptation algorithm outperforms the rest when the paths are shared with heavy traffic, which is not supported by MPTCP.

  7. Modeling of TCP-Rab throughput and its empirical study%TCP-Rab的吞吐量模型及实验研究

    Institute of Scientific and Technical Information of China (English)

    汤旭红; 刘正蓝; 朱淼良

    2004-01-01

    基于接收端通告的TCP(TCP-Rab,receiver advertisement based TCP)协议是我们实现的一种新的TCP协议,在文献[1]中对TCP-Rab的算法设计、实现进行了详细阐述.本文对TCP-Rab进行了少量改进,重点导出了TCP-Rab的吞吐量性能模型,并对TCP-Rab进行了试验研究.该模型采用统计的方法,在导出TCP-Rab的吞吐量性能模型的时候,不仅考虑了TCP连接的拥塞避免阶段对吞吐量的影响,也考虑了慢启动阶段对吞吐量的影响,同时还考虑了一个发送窗口内多个数据包随机丢失对吞吐量的影响,因此该模型能适用于实际的网络环境中.

  8. TCP Upload and Download Fairness over IEEE 802.11 Wired-cum-Wireless Heterogeneous Networks

    Institute of Scientific and Technical Information of China (English)

    REN Wei; JIN Hai

    2007-01-01

    A scheme of setting a limit to the TCP sending window size is proposed to improve the TCP fairness between upload and/or download flows in wired-cum-wireless networks. The goodput and delay of the upload and download TCP flows are compared to evaluate the TCP fairness for different schemes, which are the different combinations of setting a limit (64 or 4) to the sending window size and using the delayed acknowledgement (ACK) scheme or not. Extensive simulation results and analysis show that ( 1 )for TCP download flows, setting the limit of sending window size to 4 can improve the fairness; (2) for TCP upload flows, limiting the sending window size and using the delayed ACK strategy are both beneficial to fairness; (3) for TCP download and upload mixture flows, limiting the sending window size to a small value ( e. g. , 4) rather than using the delayed ACK strategy, is the solution to improvement of the fairness; (4) a large delay interval (200 ms or 300 ms) does not result in improvement in fairness and performance; (5) a larger TCP packet size ( 1 400 B) can improve the TCP upload goodput and decrease the download goodput; in contrast, a smaller TCP packet size (560 B) can increase the download goodput and decrease the upload goodput.

  9. A novel implementation of TCP Vegas for optical burst switched networks

    KAUST Repository

    Shihada, Basem

    2010-07-01

    TCP performance over bufferless Optical Burst Switched (OBS) networks could be significantly degraded due to the misinterpretation of network congestion status (referred to as false congestion detection). It has been reported that burst retransmission in the OBS domain can improve the TCP throughput by hiding burst loss events from the upper TCP layer, which can effectively reduce the congestion window fluctuation at the expense of introducing additional delay. However, the additional delay may cause performance degradation for delay-based TCP implementations that are sensitive to packet round trip time in estimating the network congestion status. In this paper, a novel implementation of TCP Vegas that adopts a threshold-based mechanism is proposed for identifying the network congestion status in OBS networks. Analytical models are developed to evaluate the throughput of conventional TCP Vegas and threshold-based Vegas over OBS networks with burst retransmission. Simulation is conducted to validate the analytical model and to compare threshold-based Vegas with a number of legacy TCP implementations, such as TCP Sack and TCP Reno. The analytical model can be used to obtain a proper threshold value that results in an optimal steady state TCP throughput.

  10. TCP15 modulates cytokinin and auxin responses during gynoecium development in Arabidopsis.

    Science.gov (United States)

    Lucero, Leandro E; Uberti-Manassero, Nora G; Arce, Agustín L; Colombatti, Francisco; Alemano, Sergio G; Gonzalez, Daniel H

    2015-10-01

    We studied the role of Arabidopsis thaliana TCP15, a member of the TEOSINTE BRANCHED1-CYCLOIDEA-PCF (TCP) transcription factor family, in gynoecium development. Plants that express TCP15 from the 35S CaMV promoter (35S:TCP15) develop flowers with defects in carpel fusion and a reduced number of stigmatic papillae. In contrast, the expression of TCP15 fused to a repressor domain from its own promoter causes the development of outgrowths topped with stigmatic papillae from the replum. 35S:TCP15 plants show lower levels of the auxin indoleacetic acid and reduced expression of the auxin reporter DR5 and the auxin biosynthesis genes YUCCA1 and YUCCA4, suggesting that TCP15 is a repressor of auxin biosynthesis. Treatment of plants with cytokinin enhances the developmental effects of expressing TCP15 or its repressor form. In addition, treatment of a knock-out double mutant in TCP15 and the related gene TCP14 with cytokinin causes replum enlargement, increased development of outgrowths, and the induction of the auxin biosynthesis genes YUCCA1 and YUCCA4. A comparison of the phenotypes observed after cytokinin treatment of plants with altered expression levels of TCP15 and auxin biosynthesis genes suggests that TCP15 modulates gynoecium development by influencing auxin homeostasis. We propose that the correct development of the different tissues of the gynoecium requires a balance between auxin levels and cytokinin responses, and that TCP15 participates in a feedback loop that helps to adjust this balance.

  11. TCP/IP Sockets in C# Practical Guide for Programmers

    CERN Document Server

    Makofske, David; Calvert, Kenneth L

    2004-01-01

    "TCP/IP sockets in C# is an excellent book for anyone interested in writing network applications using Microsoft .Net frameworks. It is a unique combination of well written concise text and rich carefully selected set of working examples. For the beginner of network programming, it''s a good starting book; on the other hand professionals could also take advantage of excellent handy sample code snippets and material on topics like message parsing and asynchronous programming."Adarsh Khare, SDT, .Net Frameworks Team, Microsoft CorporationThe popularity of the C# language and the .NET framework is ever rising due to its ease of use, the extensive class libraries available in the .NET Framework, and the ubiquity of the Microsoft Windows operating system, to name a few advantages. TCP/IP Sockets in C# focuses on the Sockets API, the de facto standard for writing network applications in any programming language. Starting with simple client and server programs that use TCP/IP (the Internet protocol suite), students ...

  12. TCP Issues in Mobile Ad Hoc Networks: Challenges and Solutions

    Institute of Scientific and Technical Information of China (English)

    Wei-Qiang Xu; Tie-Jun Wu

    2006-01-01

    Mobile ad hoc networks (MANETs) are a kind of very complex distributed communication systems with wireless mobile nodes that can be freely and dynamically self-organized into arbitrary and temporary network topologies. MANETs inherit several limitations of wireless networks, meanwhile make new challenges arising from the specificity of MANETs, such as route failures, hidden terminals and exposed terminals. When TCP is applied in a MANET environment, a number of tough problems have to be dealt with. In this paper, a comprehensive survey on this dynamic field is given. Specifically, for the first time all factors impairing TCP performance are identified based on network protocol hierarchy, I.e., lossy wireless channel at the physical layer; excessive contention and unfair access at the MAC layer; frail routing protocol at the network layer, the MAC layer and the network layer related mobile node; unfit congestion window size at the transport layer and the transport layer related asymmetric path. How these factors degrade TCP performance is clearly explained. Then, based on how to alleviate the impact of each of these factors listed above, the existing solutions are collected as comprehensively as possible and classified into a number of categories, and their advantages and limitations are discussed. Based on the limitations of these solutions, a set of open problems for designing more robust solutions is suggested.

  13. Estimating TCP Packet Loss Ratio from Sampled ACK Packets

    Science.gov (United States)

    Yamasaki, Yasuhiro; Shimonishi, Hideyuki; Murase, Tutomu

    The advent of various quality-sensitive applications has greatly changed the requirements for IP network management and made the monitoring of individual traffic flows more important. Since the processing costs of per-flow quality monitoring are high, especially in high-speed backbone links, packet sampling techniques have been attracting considerable attention. Existing sampling techniques, such as those used in Sampled NetFlow and sFlow, however, focus on the monitoring of traffic volume, and there has been little discussion of the monitoring of such quality indexes as packet loss ratio. In this paper we propose a method for estimating, from sampled packets, packet loss ratios in individual TCP sessions. It detects packet loss events by monitoring duplicate ACK events raised by each TCP receiver. Because sampling reveals only a portion of the actual packet loss, the actual packet loss ratio is estimated statistically. Simulation results show that the proposed method can estimate the TCP packet loss ratio accurately from a 10% sampling of packets.

  14. Analysis and application of C++layer protocol TCP/IP%TCP/IP应用层协议分析与C++实现

    Institute of Scientific and Technical Information of China (English)

    杜晓春; 刘婉妮; 王宏

    2013-01-01

    With the rapid development of the Internet today,as Internet based TCP/IP protocol has penetrated into every aspect of our lives.This paper makes a detailed analysis on the application layer protocol in TCP/IP protocol;then introduces how to use the C++ programming language,the TCP/IP protocol Telnet,FTP application layer protocol in a visual,easy operation of the client/server mode (C/S mode) show.In order to facilitate the people to better understand the TCP/IP protocol,the work principle of TCP/IP protocol and the reference value for network application development.%在互联网高速发展的今天,作为Internet国际互联网络基础的TCP/IP协议已经渗透到我们生活的各个方面。本文首先对TCP/IP协议中的应用层协议进行了详细的分析;然后介绍了如何运用C++语言进行编程,将TCP/IP协议中的Telnet、FTP等应用层协议以一种可视化、易操作的客户端/服务器端模式(C/S模式)展现出来。从而便于人们更好的认识和理解TCP/IP协议,对了解TCP/IP协议的工作原理及进行网络应用程序开发一定的参考价值。

  15. Ornithine and Homocitrulline Impair Mitochondrial Function, Decrease Antioxidant Defenses and Induce Cell Death in Menadione-Stressed Rat Cortical Astrocytes: Potential Mechanisms of Neurological Dysfunction in HHH Syndrome.

    Science.gov (United States)

    Zanatta, Ângela; Rodrigues, Marília Danyelle Nunes; Amaral, Alexandre Umpierrez; Souza, Débora Guerini; Quincozes-Santos, André; Wajner, Moacir

    2016-09-01

    Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is caused by deficiency of ornithine translocase leading to predominant tissue accumulation and high urinary excretion of ornithine (Orn), homocitrulline (Hcit) and ammonia. Although affected patients commonly present neurological dysfunction manifested by cognitive deficit, spastic paraplegia, pyramidal and extrapyramidal signs, stroke-like episodes, hypotonia and ataxia, its pathogenesis is still poorly known. Although astrocytes are necessary for neuronal protection. Therefore, in the present study we investigated the effects of Orn and Hcit on cell viability (propidium iodide incorporation), mitochondrial function (thiazolyl blue tetrazolium bromide-MTT-reduction and mitochondrial membrane potential-ΔΨm), antioxidant defenses (GSH) and pro-inflammatory response (NFkB, IL-1β, IL-6 and TNF-α) in unstimulated and menadione-stressed cortical astrocytes that were previously shown to be susceptible to damage by neurotoxins. We first observed that Orn decreased MTT reduction, whereas both amino acids decreased GSH levels, without altering cell viability and the pro-inflammatory factors in unstimulated astrocytes. Furthermore, Orn and Hcit decreased cell viability and ΔΨm in menadione-treated astrocytes. The present data indicate that the major compounds accumulating in HHH syndrome impair mitochondrial function and reduce cell viability and the antioxidant defenses in cultured astrocytes especially when stressed by menadione. It is presumed that these mechanisms may be involved in the neuropathology of this disease.

  16. TCP-RC增强Ad hoc网络TCP性能%Enhance TCP Performance in Ad hoc Network by TCP-RC

    Institute of Scientific and Technical Information of China (English)

    周建新; 石冰心

    2006-01-01

    目前改善Ad hoc网络中TCP性能的方法通常在路由中断/变化时暂时性地冷冻TCP连接,在路由重建后从冷冻的状态继续TCP传输.但TCP源端和目的端之间的路由在中断前和重建后可能完全不同,所以路由重建后TCP仍从路由中断前的状态继续TCP传输并不一定合适.本文提出了TCP-RC,它在路由重建后重新计算cwnd和ssthresh,使得TCP恢复传输时能根据当前TCP连接上的容量自适应地调整发送速率,降低突发流量造成网络拥塞的可能性.仿真表明TCP-RC在Ad hoc网络中取得了更好TCP性能.

  17. Performance of TCP-Throughput on NS2 by Using Different Simulation Parameters

    Directory of Open Access Journals (Sweden)

    Dr. Neeraj Bhargava , Dr. Ritu Bhargava, Anchal Kumawat , Bharat Kumar

    2012-12-01

    Full Text Available ns2 is a discrete event simulator for networkingresearch, which works at the packet level. Here, wewill be using ns2 to simulate traffic congestion ofTCP and UDP packets inside a network. ns2 ispopularly used in the simulation of routing andmulticast protocols and is heavily used in ad-hocnetworking research. ns2 supports networkprotocols (TCP, UDP, HTTP, Routing algorithms,MAC etc. for offering simulation results for wiredand wireless networks. When using TCP to transferdata the two most important factors are the TCPwindow size and the round trip latency. This paperdeals the effect that the size of the flow controlwindow has on the throughput of a TCP connectionby using simulation parameters like-packet delay(sec, bandwidth, file-size (bytes and to implementnetwork fed with TCP traffic and backgroundtraffic. The objective of this paper is to observe theperformance of TCP

  18. A new Grid Product of Tropical Cyclone Precipitation (TCP) for North America from 1930 to 2013

    Science.gov (United States)

    Zhu, L.

    2015-12-01

    We first developed a new method that collects daily TCP by using historical storm tracks and precipitation observation based on daily rain gauges in both U.S. and Mexico and calibrated it with satellite precipitation observation. We used a parametrized wind field to correct the possible under-estimations of precipitation in rain gauges. Grid interpolation parameters were optimized by testing different historical rain gauge densities and comparing our grid estimation of TCP and the observation from TRMM Multi-satellite Precipitation Analysis (3B42) by for the data available period from 1998 to 2013. The calibrated method was then used for the whole 94 years of TCP estimation. The preliminary result shows that the frequency of TCP events does not have significant change but the TCP intensity has significant increasing trends, especially in certain locations in North Carolina and Yucatan Peninsula in Mexico. This new long term TCP climatology can potentially assist model calibration and disaster prevention/mitigation.

  19. FAST TCP over optical burst switched networks: Modeling and stability analysis

    KAUST Repository

    Shihada, Basem

    2013-04-01

    FAST TCP is important for promoting data-intensive applications since it can cleverly react to both packet loss and delay for detecting network congestion. This paper provides a continuous time model and extensive stability analysis of FAST TCP congestion-control mechanism in bufferless Optical Burst Switched Networks (OBS). The paper first shows that random burst contentions are essential to stabilize the network, but cause throughput degradation in FAST TCP flows when a burst with all the packets from a single round is dropped. Second, it shows that FAST TCP is vulnerable to burst delay and fails to detect network congestion due to the little variation of round-trip time, thus unstable. Finally it shows that introducing extra delays by implementing burst retransmission stabilizes FAST TCP over OBS. The paper proves that FAST TCP is not stable over barebone OBS. However, it is locally, exponentially, and asymptotically stable over OBS with burst retransmission.

  20. Some Aspects about a Self-Testing Solution for Implementing the TCP/IP Protocol

    Directory of Open Access Journals (Sweden)

    Daniela E.Popescu

    2008-05-01

    Full Text Available TCP is a connection-oriented, end-to-endreliable protocol designed to fit into a layeredhierarchy of protocols which support multi-networkapplications. The paper focuses on comparing theefficiencies of realizing a hardware implementationfor the TCP protocol.In order to estimate the advantages of such ahardware implementation we show in this paper thecomparative results of the classical implementationwith that of a self-testing implementation of TCP.

  1. 关于上Internet网和TCP/IP协议的实用技术

    Institute of Scientific and Technical Information of China (English)

    Tracy Thomas; 梁合庆

    2000-01-01

    @@ TCP/IP包括一系列协议 首先,应理解我们所说的TCP/IP是统指一系列的协议,其中包括TCP(传输控制协议)、UDP(用户数据报协议)、IP(Internet协议),还有一些更低层的连接层协议,如Ethernet(以太网协议)等.

  2. 基于TOE技术的硬线TCP/IP协议栈设计

    Institute of Scientific and Technical Information of China (English)

    徐俊; 黄静; 张泰然; 李刚

    2008-01-01

    本文介绍了当今互联网的发展和TOE技术,介绍了TCP/IP协议栈的原理,提出了TCP/IP协议栈芯片的设计。在设计中,实现了剪裁了的TCP/IP协议栈,主要实现了TCP协议、UDP协议、IP协议、ARP协议和ICMP协议。

  3. Performance Analysis of TCP Vegas-based LTE Network Congestion Control Algorithm%基于TCP Vegas的LTE网络拥塞控制算法性能分析

    Institute of Scientific and Technical Information of China (English)

    刘靖

    2015-01-01

    TCP Vegas和TCP Reno相比,虽然性能更强,吞吐量更高,但若将TCP Vegas部署在新的网络上仍存在较多障碍.以4G的LTE系统中部署TCP Vegas为例,分别对慢启动阶段的阈值设置和拥塞避免阶段的拥塞避免机制作相应改进.使用NS-2网络仿真LTE模型,结果表明TCP Vegas与TCP Reno相比具有更好的性能.

  4. TcpM: a novel relaxase that mediates transfer of large conjugative plasmids from Clostridium perfringens.

    Science.gov (United States)

    Wisniewski, Jessica A; Traore, Daouda A; Bannam, Trudi L; Lyras, Dena; Whisstock, James C; Rood, Julian I

    2016-03-01

    Conjugative transfer of toxin and antibiotic resistance plasmids in Clostridium perfringens is mediated by the tcp conjugation locus. Surprisingly, neither a relaxase gene nor an origin of transfer (oriT) has been identified on these plasmids, which are typified by the 47 kb tetracycline resistance plasmid pCW3. The tcpM gene (previously called intP) encodes a potential tyrosine recombinase that was postulated to be an atypical relaxase. Mutagenesis and complementation studies showed that TcpM was required for wild-type transfer of pCW3 and that a tyrosine residue, Y259, was essential for TcpM activity, which was consistent with the need for a relaxase-mediated hydrophilic attack at the oriT site. Other catalytic residues conserved in tyrosine recombinases were not required for TcpM activity, suggesting that TcpM was not a site-specific recombinase. Mobilization studies led to the identification of the oriT site, which was located in the 391 bp intergenic region upstream of tcpM. The oriT site was localized to a 150 bp region, and gel mobility shift studies showed that TcpM could bind to this region. Based on these studies we postulate that conjugative transfer of pCW3 involves the atypical relaxase TcpM binding to and processing the oriT site to initiate plasmid transfer.

  5. Preparation and Drug-release Behavior of β-TCP Ceramics Drug Carrier in vitro

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qihuan; YAN Xin; YAN Yuhua; DAI Honglian; JIANG Xin; LI Shipu

    2012-01-01

    β-TCP ceramics drug carrier was first prepared and characterized.SEM showed that β-TCP carrier was in porous amorphous structure with diameters around 10 μm.The physical properties including apparent porosity,volume-weight,tensile strength and the permeability were measured and the results indicated those properties fit the clinical usage of β-TCP drug carrier.Furthermore,drug release experiment in vitro showed that the carrier could prolong drug release in simulated body fluid which provides basis for the clinical use of β-TCP ceramics as drug carrier.

  6. Efficient enhancing scheme for TCP performance over satellite-based internet

    Institute of Scientific and Technical Information of China (English)

    Wang Lina; Gu Xuemai

    2007-01-01

    Satellite link characteristics drastically degrade transport control protocol (TCP) performance. An efficient performance enhancing scheme is proposed. The improvement of TCP performance over satellite-based Intemet is accomplished by protocol transition gateways at each end ora satellite link. The protocol which runs over a satellite link executes the receiver-driven flow control and acknowledgements- and timeouts-based error control strategies. The validity of this TCP performance enhancing scheme is verified by a series of simulation experiments. Results show that the proposed scheme can efficiently enhance the TCP performance over satellite-based Intemet and ensure that the available bandwidth resources of the satellite link are fully utilized.

  7. Expression of caveolin-1 in the early phase of beta-TCP implanted in dog mandible.

    Science.gov (United States)

    Chou, Cherng-Tzeh; Bhawal, Ujjal K; Watanabe, Nobuyuki; Kuboyama, Noboru; Chang, Wei-Jen; Lee, Sheng-Yang; Abiko, Yoshimitsu

    2013-07-01

    Caveolin is an essential and signature protein of caveolae. Caveolin-1 participates in signal transduction processes by acting as a scaffolding protein that concentrates, organizes and functional regulates signalling molecules within caveolar membranes. Beta-tricalcium phosphate (β-TCP) has been widely used for scaffold in tissue engineering due to its high biodegradability, osteoconductivity, easy manipulation, and lack of histotoxicity. To better understand the role of caveolin-1 in bone homeostasis and response to β-TCP scaffold, β-TCP was implanted into the dog mandible defects in beagle dogs, and gene expression profiles were examined focused on the molecular components involved in caveolin-1 regulation. Here we showed the quantitative imageology analysis characterized using in vivo micro-computed tomography (CT) images at 4 and 7 days after β-TCP implanted in dog mandibles. The bone reformation by using the β-TCP scaffolds began within 4 days of surgery, and was healing well at 7 days after surgery. Higher mRNA level of caveolin-1 was observed in β-TCP-implanted Beagle dog mandibles compared with controls at day 4 and day 7 post-surgery. The enhancement of caveolin-1 by β-TCP was further confirmed by immunohistochemistry and immunofluorescence analysis. We further revealed increased Smad7 and Phospho Stat3 expression in β-TCP-implanted specimens. Taken together, these results suggest that the enhancement of caveolin-1 play an important role in accelerating bone formation by β-TCP.

  8. 2,4,6-trichlorophenol (TCP) photobiodegradation and its effect on community structure.

    Science.gov (United States)

    Zhang, Yongming; Pu, Xuejing; Fang, Miaomiao; Zhu, Jun; Chen, Lujun; Rittmann, Bruce E

    2012-07-01

    The mechanisms occurring in a photolytic circulating-bed biofilm reactor (PCBBR) treating 2,4,6-trichlorophenol (TCP) were investigated using batch experiments following three protocols: photodegradation alone (P), biodegradation alone (B), and intimately coupled photodegradation and biodegradation (P&B). Initially, the ceramic particles used as biofilm carriers rapidly adsorbed TCP, particularly in the B experiments. During the first 10 min, the TCP removal rate for P&B was equal to the sum of the rates for P and B, and P&B continued to have the greatest TCP removal, with the TCP concentration approaching zero only in the P&B experiments. When phenol, an easily biodegradable compound, was added along with TCP in order to promote TCP mineralization by means of secondary utilization, P&B was superior to P and B in terms of mineralization of TCP, giving 95% removal of chemical oxygen demand (COD). The microbial communities, examined by clone libraries, changed dramatically during the P&B experiments. Whereas Burkholderia xenovorans, a known degrader of chlorinated aromatics, was the dominant strain in the TCP-acclimated inoculum, it was replaced in the P&B biofilm by strains noted for biofilm formation and biodegrading non-chlorinated aromatics.

  9. Genome-wide identification and expression analysis of TCP transcription factors in Gossypium raimondii.

    Science.gov (United States)

    Ma, Jun; Wang, Qinglian; Sun, Runrun; Xie, Fuliang; Jones, Don C; Zhang, Baohong

    2014-10-16

    Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play versatile functions in multiple aspects of plant growth and development. However, no systematical study has been performed in cotton. In this study, we performed for the first time the genome-wide identification and expression analysis of the TCP transcription factor family in Gossypium raimondii. A total of 38 non-redundant cotton TCP encoding genes were identified. The TCP transcription factors were divided into eleven subgroups based on phylogenetic analysis. Most TCP genes within the same subfamily demonstrated similar exon and intron organization and the motif structures were highly conserved among the subfamilies. Additionally, the chromosomal distribution pattern revealed that TCP genes were unevenly distributed across 11 out of the 13 chromosomes; segmental duplication is a predominant duplication event for TCP genes and the major contributor to the expansion of TCP gene family in G. raimondii. Moreover, the expression profiles of TCP genes shed light on their functional divergence.

  10. Fabrication of Porous α-TCP/Gellan Gum Scaffold for Bone Tissue Engineering.

    Science.gov (United States)

    Wen, Jian; Kim, Ill Yong; Kikuta, Koichi; Ohtsuki, Chikara

    2016-03-01

    α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2) receives great attention for bone repairing due to its biodegradability and capability of transformation to human bone's main inorganic components, hydroxyapatite (HAp). α-TCP porous scaffold is easily procurable by sintering of the low-temperature polymorph of TCP, β-TCR Still, porous body of α-TCP is too brittle to being handled and shaped, limiting its clinical application as implant materials. To improve mechanical properties of α-TCP porous scaffold, the present study focused on coating of a type of polysaccharides on α-TCP scaffolds. Gellan gum was chosen as the polysaccharide for coating because of its biodegradability as well as the potential acting as substrate for HAp deposition during hydration of α-TCP after exposure to body fluid. After coating of gellan gum on α-TCP scaffolds with porosity of 75 vol%, the compressive strength increased from 0.45 MPa to around 2.00 MPa. Among the coated scaffold, the maximum compressive strength, 3.97 MPa, was obtained on the scaffold with porosity of 63 vol%. Improvement of mechanical properties of α-TCP/gellan gum composites was achieved to show easy handling performance for a bone substitute for tissue repairing. The dissolving rate of the coated scaffolds was also controlled by adjusting the concentration of GG solutions.

  11. Analysis of functional redundancies within the Arabidopsis TCP transcription factor family.

    Science.gov (United States)

    Danisman, Selahattin; van Dijk, Aalt D J; Bimbo, Andrea; van der Wal, Froukje; Hennig, Lars; de Folter, Stefan; Angenent, Gerco C; Immink, Richard G H

    2013-12-01

    Analyses of the functions of TEOSINTE-LIKE1, CYCLOIDEA, and PROLIFERATING CELL FACTOR1 (TCP) transcription factors have been hampered by functional redundancy between its individual members. In general, putative functionally redundant genes are predicted based on sequence similarity and confirmed by genetic analysis. In the TCP family, however, identification is impeded by relatively low overall sequence similarity. In a search for functionally redundant TCP pairs that control Arabidopsis leaf development, this work performed an integrative bioinformatics analysis, combining protein sequence similarities, gene expression data, and results of pair-wise protein-protein interaction studies for the 24 members of the Arabidopsis TCP transcription factor family. For this, the work completed any lacking gene expression and protein-protein interaction data experimentally and then performed a comprehensive prediction of potential functional redundant TCP pairs. Subsequently, redundant functions could be confirmed for selected predicted TCP pairs by genetic and molecular analyses. It is demonstrated that the previously uncharacterized class I TCP19 gene plays a role in the control of leaf senescence in a redundant fashion with TCP20. Altogether, this work shows the power of combining classical genetic and molecular approaches with bioinformatics predictions to unravel functional redundancies in the TCP transcription factor family.

  12. Evaluation of Advanced TCP Stacks on Fast Long-Distance Production Networks

    Energy Technology Data Exchange (ETDEWEB)

    Bullot, H.

    2004-04-08

    With the growing needs of data intensive science, such as High Energy Physics, and the need to share data between multiple remote computer and data centers worldwide, the necessity for high network performance to replicate large volumes (TBytes) of data between remote sites in Europe, Japan and the U.S. is imperative. Currently, most production bulk-data replication on the network utilizes multiple parallel standard (Reno based) TCP streams. Optimizing the window sizes and number of parallel stream is time consuming, complex, and varies (in some cases hour by hour) depending on network configurations and loads. We therefore evaluated new advanced TCP stacks that do not require multiple parallel streams while giving good performances on high speed long-distance network paths. In this paper, we report measurements made on real production networks with various TCP implementations on paths with different Round Trip Times (RTT) using both optimal and sub-optimal window sizes. We compared the New Reno TCP with the following stacks: HS-TCP, Fast TCP, S-TCP, HSTCP-LP, H-TCP and Bic-TCP. The analysis will compare and report on the stacks in terms of achievable throughput, impact on RTT, intra- and inter-protocol fairness, stability, as well as the impact of reverse traffic. We also report on some tentative results from tests made on unloaded 10 Gbps paths during SuperComputing 2003.

  13. A Comparison of the TCP Variants Performance over different Routing Protocols on Mobile Ad Hoc Networks

    Directory of Open Access Journals (Sweden)

    S. R. Biradar

    2010-03-01

    Full Text Available We describe a variant of TCP (Tahoe, Vegas, TCP is most widely used transport protocol in both wired and wireless networks. In mobile ad hoc networks, the topology changes frequently due to mobile nodes, this leads to significant packet losses and network throughput degradation. This is due to the fact that TCP fails to distinguish the path failure and network congestion. In this paper, the performances of TCP over different routing (DSR, AODV and DSDV protocols in ad hoc networks wasstudied by simulation experiments and results are reported.

  14. TCP/IP协议中实现远程文件的传输%Remote File Transport by TCP/IP Protocol

    Institute of Scientific and Technical Information of China (English)

    任军

    2013-01-01

    TCP/IP是Internet的基本协议。远程文件传输是以TCP/IP协议为基础,采用Delphi控件,将TCP/IP通信函数封装在ActiveX控件中,通过对ActiveX控件提供的对外接口的调用,隐藏了TCP/IP的实际实现过程,直接实现文件传输。程序采用客户机/服务器体系,服务器侦听连接请求,客户机发起请求,客户机与服务器合作实现文件的双向传输。%TCP/IP is base protocol of Internet. The article of Remote File Transport is base on TCP/IP protocol, Using the control of programmable language Delphi, Because all function of implementation are encapsulated in activeX control, application program interface can be invoked easily, Executing TCP/IP function is hid, So finishing remote file transport .The program use Client/Server system. Server listen in to Client requesting,Client sent request ,Client and Server can work well together to accomplish the file bidirectional transportation.

  15. TCP Freeze-Probing Enhancement for Mobile Ad Hoc Networks%基于无线自组织网络的TCP Freeze-Probing改进协议

    Institute of Scientific and Technical Information of China (English)

    王波; 范平志

    2005-01-01

    传统的TCP协议在有线网络中能够良好地工作,但用于无线自组织网络时则性能有所下降.其原因在于,传统的TCP协议无法分辨网络丢包原因,如网络拥塞、链路断开、信道错误或者链路改变.为了提高TCP协议在无线自组织网络中的性能,提出了一种TCP协议的改进方案TCP Freeze-Probing.该方案是一种端到端方法,不需要网络中间节点的反馈合作同时,提出了一种基于TCP Freeze-Probing的吞吐量模型并利用仿真对模型进行了验证.分析和仿真结果表明,该方案能够有效地改进TCP在无线自组织网络的性能.%Traditional Transmission Control Protocol (TCP) works well in wired network but suffers from performance degradation in mobile ad-hoc networks (MANET) due to the fact that it cannot distinguish packet losses due to congestion from packet losses due to link breakage, channel error and route changes. In this paper, an enhanced TCP, named TCP Freeze-Probing, is proposed to improve the TCP performance in mobile ad-hoc networks. TCP Freeze-Probing is an end-to-end approach that does not need the cooperation of the intermediate nodes in the network. Besides, a throughput model for TCP Freeze-Probing is given, which is validated through simulation. It is shown by analysis and simulation that the proposed approach can greatly improve the TCP performance in MANET.

  16. 无线网络中TCP/NC协议性能分析与仿真验证%Performance Analysis and Simulation Verification of TCP/NC Protocol in Wireless Network

    Institute of Scientific and Technical Information of China (English)

    葛卫民; 朱海颖; 李娟

    2015-01-01

    In order to improve the traditional Transmission Control Protocol( TCP) performance in wireless networks, this paper solves throughput rate model of three TCP protocols,TCP Reno,TCP Vegas and TCP/NC based on network coding through Matlab,and analyzes the theoretical value of the three models in different networks,and verifies whether TCP/NC model can improve its throughput rate. The three models are simulated through NS-2,and simulation results show the effectiveness of TCP/NC protocol and its analysis model.%为改进传统传输控制协议( TCP)在无线网络中的性能,运用Matlab对TCP Reno,TCP Vegas和基于网络编码的TCP/NC吞吐率分析模型进行数值求解,分析3个模型在不同网络环境下应达到的理论值,验证TCP/NC模型在理论上能否提高其吞吐率。基于NS-2对3种吞吐率模型进行仿真,结果表明,TCP/NC及其分析模型可有效改进TCP协议。

  17. Role of UV photolysis in accelerating the biodegradation of 2,4,6-TCP.

    Science.gov (United States)

    Wang, Wenbing; Kirumba, George; Zhang, Yongming; Wu, Yanqing; Rittmann, Bruce E

    2015-09-18

    2,4,6-TCP, a kind of chlorinated aromatic and aliphatic compound, is difficult to be biodegraded by ordinary microorganisms. UV photolysis and biodegradation of 2,4,6-TCP by Bacillus amyloliquefaciens intimate coupling is a potential means to accelerate its biotransformation. The initial steps of 2,4,6-TCP biodegradation involve mono-oxygenation reactions that have molecular oxygen and an intracellular electron carrier as cosubstrates. It was demonstrated that B. amyloliquefaciens has the 2,4,6-TCP monooxygenase gene tcpA which could encode 2,4,6-TCP monooxygenase (TCP-MO). TCP-MO would catalytically decompose 2,4,6-TCP into 2,6-DCHQ. We employed an internal loop photolytic biofilm reactor for 2,4,6-TCP degradation. Sequentially coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P + B (TCP(UV) + phenol) protocol was higher by 77 and 103 % when compared to B (TCP + phenol) and B (TCP-only) protocols respectively. The corresponding loss rate coefficient (k) values were 0.069, 0.039, 0.034 mg/L·min(-1) respectively. This is because UV photolysis converted 2,4,6-TCP into its intermediates: 2,4-dichlorophenol (2,4-DCP), 4-monochlorophenol (4-MCP), phenol, 2,6-dichloro-p-hydroquinone (2,6-DCHQ), with all displaying less inhibition to bacterial action. In addition, phenol was the crucial UV-photolysis product from 2,4,6-TCP, its catabolic oxidation generating internal electron carriers that may accelerate the initial steps of 2,4,6-TCP biodegradation. Intimately coupled photolysis and biodegradation experimental results suggested that 2,4,6-TCP removal rate in P&B (TCP + phenol) protocol was higher by 166 and 681 % when compared to P&B (TCP-only) and P + B protocols respectively. The corresponding loss rate coefficient (k) values were 0.539, 0.203, 0.069 mg/L·min(-1) respectively. It provided sufficient evidence to demonstrate that intimately coupled photolysis and biodegradation accelerated 2,4,6-TCP

  18. Comparison of TCP automatic tuning techniques for distributed computing

    Energy Technology Data Exchange (ETDEWEB)

    Weigle, E. H. (Eric H.); Feng, W. C. (Wu-Chun)

    2002-01-01

    Rather than painful, manual, static, per-connection optimization of TCP buffer sizes simply to achieve acceptable performance for distributed applications, many researchers have proposed techniques to perform this tuning automatically. This paper first discusses the relative merits of the various approaches in theory, and then provides substantial experimental data concerning two competing implementations - the buffer autotuning already present in Linux 2.4.x and 'Dynamic Right-Sizing.' This paper reveals heretofore unknown aspects of the problem and current solutions, provides insight into the proper approach for various circumstances, and points toward ways to further improve performance. TCP, for good or ill, is the only protocol widely available for reliable end-to-end congestion-controlled network communication, and thus it is the one used for almost all distributed computing. Unfortunately, TCP was not designed with high-performance computing in mind - its original design decisions focused on long-term fairness first, with performance a distant second. Thus users must often perform tortuous manual optimizations simply to achieve acceptable behavior. The most important and often most difficult task is determining and setting appropriate buffer sizes. Because of this, at least six ways of automatically setting these sizes have been proposed. In this paper, we compare and contrast these tuning methods. First we explain each method, followed by an in-depth discussion of their features. Next we discuss the experiments to fully characterize two particularly interesting methods (Linux 2.4 autotuning and Dynamic Right-Sizing). We conclude with results and possible improvements.

  19. Embedded TCP/IP Chip Based on DW8051 Core

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    As remote control for electric home appliances thro ug h the Internet becomes more common, many compannies today launched a new corpora te initiative to develop advanced embedded solutions for Internet connectivity t hat can be applied to a boundless number of products such as information applian ces and non-PC devices. The most representative products are CMX-MicroNet which provides true TCP/IP ca pabilities for 8-bit and 16-bit microprocessors and eZ80Internet Engine which provides easy Internet connect...

  20. Un nuevo ataque a TCP para redes de radios cognitivas

    OpenAIRE

    León Abarca, Olga; Hernández Serrano, Juan; Soriano Ibáñez, Miguel

    2009-01-01

    Los dispositivos de radios cognitivas emergen como una prometedora tecnología que ha de permitir un mejor uso del espectro electro-magnético. Estos dispositivos se caracterizan por ser capaces de observar y entender su entorno, y cambiar consecuentemente su modo de operación. Sin embargo, estas propiedades “cognitivas” conllevan nuevos retos de seguridad. En este artículo se presenta un nuevo ataque a las conexiones TCP en redes de radios cognitivas, se proponen soluciones para mitigarlo y se...

  1. Un nuevo ataque a TCP para redes de radios cognitivas

    OpenAIRE

    León Abarca, Olga; Hernández Serrano, Juan; Soriano Ibáñez, Miguel

    2009-01-01

    Los dispositivos de radios cognitivas emergen como una prometedora tecnología que ha de permitir un mejor uso del espectro electro-magnético. Estos dispositivos se caracterizan por ser capaces de observar y entender su entorno, y cambiar consecuentemente su modo de operación. Sin embargo, estas propiedades “cognitivas” conllevan nuevos retos de seguridad. En este artículo se presenta un nuevo ataque a las conexiones TCP en redes de radios cognitivas, se proponen soluciones para mitigarlo y se...

  2. Loss Strategies for Competing TCP/IP Connections

    OpenAIRE

    Altman, Eitan; El-Azouzi, Rachid; Ros, David; Tuffin, Bruno

    2004-01-01

    We study in this paper two competing TCP connections that share a common bottleneck link. When congestion occurs, one (or both) connections will suffer a loss that will cause its throughput to decrease by a multiplicative factor. The identity of the connection that will suffer a loss is determined by a randomized «loss strategy» that may depend on the throughputs of the connections at the congestion instant. We analyze several loss strategies: the one in which the identity of loss is independ...

  3. The CASCAM network control system based on TCP/IP

    Science.gov (United States)

    Ren, S. B.; Yao, Y. Q.; Yao, D. Z.

    2004-05-01

    The paper presents the CASCAM network control system based on the TCP/IP protocol. In order to realize the Client/Server model in network communication between the workstation and personal computer efficiently, two C++ classes, client and server, were developed in the system. The script language Tcl/Tk was used in programming the system control pane in the Client. With loading the dynamic library, the Client sends the request to the Server through the network, then the Server analyzes the request and controls the camera system.

  4. Characterization of TCP-1 probes for molecular imaging of colon cancer.

    Science.gov (United States)

    Liu, Zhonglin; Gray, Brian D; Barber, Christy; Bernas, Michael; Cai, Minying; Furenlid, Lars R; Rouse, Andrew; Patel, Charmi; Banerjee, Bhaskar; Liang, Rongguang; Gmitro, Arthur F; Witte, Marlys H; Pak, Koon Y; Woolfenden, James M

    2016-10-10

    Molecular probes capable of detecting colorectal cancer (CRC) are needed for early CRC diagnosis. The objective of this study was to characterize c[CTPSPFSHC]OH (TCP-1), a small peptide derived from phage display selection, for targeting human CRC xenografts using technetium-99m ((99m)Tc)-labeled TCP-1 and fluorescent cyanine-7 (Cy7)-labeled form of the peptide (Cy7-TCP-1). (99m)Tc-TCP-1 was generated by modifying TCP-1 with succinimidyl-6-hydrazino-nicotinamide (S-HYNIC) followed by radiolabeling. In vitro saturation binding experiments were performed for (99m)Tc-TCP-1 in human HCT116 colon cancer cells. SCID mice with human HCT116 cancer xenografts were imaged with (99m)Tc-TCP-1 or control peptide using a small-animal SPECT imager: Group I (n=5) received no blockade; Group II (n=5) received a blocking dose of non-radiolabeled TCP-1. Group III (n=5) were imaged with (99m)Tc-labeled control peptide (inactive peptide). SCID mice with human PC3 prostate cancer xenografts (Group IV, n=5) were also imaged with (99m)Tc-TCP-1. Eight additional SCID mice bearing HCT116 xenografts in dorsal skinfold window chambers (DSWC) were imaged by direct positron imaging of (18)F-fluorodeoxyglucose ((18)F-FDG) and fluorescence microscopy of Cy7-TCP-1. In vitro(99m)Tc-HYNIC-TCP-1 binding assays on HCT 116 cells indicated a mean Kd of 3.04±0.52nM. In cancer xenografts, (99m)Tc-TCP-1 radioactivity (%ID/g) was 1.01±0.15 in the absence of blockade and was reduced to 0.26±0.04 (PTCP-1 or HCT116 tumors with inactive peptide. Cy7-TCP-1 activity localized not only in metabolically active tumors, as defined by (18)F-FDG imaging, but also in peritumoral microvasculature. In conclusion, TCP-1 probes may have a distinct targeting mechanism with high selectivity for CRC and tumor-associated vasculature. Molecular imaging with TCP-1 probes appears promising to detect malignant colorectal lesions.

  5. The cotton transcription factor TCP14 functions in auxin-mediated epidermal cell differentiation and elongation.

    Science.gov (United States)

    Wang, Miao-Ying; Zhao, Pi-Ming; Cheng, Huan-Qing; Han, Li-Bo; Wu, Xiao-Min; Gao, Peng; Wang, Hai-Yun; Yang, Chun-Lin; Zhong, Nai-Qin; Zuo, Jian-Ru; Xia, Gui-Xian

    2013-07-01

    Plant-specific TEOSINTE-BRANCHED1/CYCLOIDEA/PCF (TCP) transcription factors play crucial roles in development, but their functional mechanisms remain largely unknown. Here, we characterized the cellular functions of the class I TCP transcription factor GhTCP14 from upland cotton (Gossypium hirsutum). GhTCP14 is expressed predominantly in fiber cells, especially at the initiation and elongation stages of development, and its expression increased in response to exogenous auxin. Induced heterologous overexpression of GhTCP14 in Arabidopsis (Arabidopsis thaliana) enhanced initiation and elongation of trichomes and root hairs. In addition, root gravitropism was severely affected, similar to mutant of the auxin efflux carrier PIN-FORMED2 (PIN2) gene. Examination of auxin distribution in GhTCP14-expressing Arabidopsis by observation of auxin-responsive reporters revealed substantial alterations in auxin distribution in sepal trichomes and root cortical regions. Consistent with these changes, expression of the auxin uptake carrier AUXIN1 (AUX1) was up-regulated and PIN2 expression was down-regulated in the GhTCP14-expressing plants. The association of GhTCP14 with auxin responses was also evidenced by the enhanced expression of auxin response gene IAA3, a gene in the AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) family. Electrophoretic mobility shift assays showed that GhTCP14 bound the promoters of PIN2, IAA3, and AUX1, and transactivation assays indicated that GhTCP14 had transcription activation activity. Taken together, these results demonstrate that GhTCP14 is a dual-function transcription factor able to positively or negatively regulate expression of auxin response and transporter genes, thus potentially acting as a crucial regulator in auxin-mediated differentiation and elongation of cotton fiber cells.

  6. TCP- Costco Reno: New Variant by Improving Bandwidth Estimation to adapt over MANETs

    Directory of Open Access Journals (Sweden)

    Prakash B. Khelage

    2014-01-01

    Full Text Available The Transmission Control Protocol (TCP is traditional, dominant and has been de facto standard protocol, used as transport agent at transport layer of TCP/IP protocol suite. Basically it is designed to provide reliability and assure guaranty to end-to-end delivery of data over unreliable networks. In practice, most TCP deployments have been carefully designed in the context of wired networks. Ignoring the properties of wireless Ad Hoc Networks, therefore it can lead to TCP implementations with poor performance. The problem of TCP and all its existing variations within MANETs resides in its inability to distinguish between different data packet loss causes, whenever the data loss occur traditional TCP congestion control algorithm assumes loss is due to congestion episode and reduces sending parameters value unnecessary. Thus, TCP has not always the optimum behavior in front of packet losses which might cause network performance degradation and resources waste. In order to adapt TCP over mobile Ad hoc environment, improvements have been proposed based on RTT and BW estimation technique in the literature to help TCP to differentiate accurate causes between the different types of losses. But still does not handle all the problems accurately and effectively. In this paper, a proposed TCP-Costco Reno a New Variant, accurately estimates the available bandwidth over Mobile Ad Hoc networks and sets sending rate accordingly to maximize utilization of available resources and hence improves performance of TCP over mobile Ad hoc networks. The results of the simulation indicate an improvement in throughput over interference, link failure and signal loss validation scenarios. Further, it shows highest average of average throughput then those variants which are most successful over MANETs.

  7. TCP/IP Protocols Analysis and Program About Communication Application%TCP/IP协议分析及通信应用编程

    Institute of Scientific and Technical Information of China (English)

    狄博

    2006-01-01

    分析了TCP/IP协议的体系结构、组成与功能以及通过TCP/IP协议实现异构型网络互连的机理.对TCP/IP协议提供的两种通信功能进行了分析,辩证地提出了它们不同的应用场合.最后,给出了在TCP/IP基础上开发通信应用程序的编程模型和实现要点,对用户开发应用程序有一定参考意义.

  8. Clinical trials update from the joint European Society and World Congress of Cardiology meeting: PEP-CHF, ACCLAIM and the HHH study.

    Science.gov (United States)

    Cleland, John G F; Coletta, Alison P; Clark, Andrew L

    2006-10-01

    This article provides information and a commentary on trials relevant to the pathophysiology, prevention and treatment of heart failure, presented at the joint European Society and World Congress of Cardiology meeting held in Barcelona in September 2006. All reports should be considered as preliminary data, as analyses may change in the final publication. The PEP-CHF study suggests that perindopril improves symptoms and functional capacity and may reduce heart failure hospitalisations in patients with diastolic heart failure. Although immune modulation therapy failed to reduce the incidence of all-cause mortality and cardiovascular hospitalisations in the ACCLAIM study, the observed differences in outcome in some heart failure patients warrants further investigation. The HHH study failed to show a beneficial effect of telemonitoring over usual care in patients with heart failure but potentially important country interactions were observed.

  9. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

    Directory of Open Access Journals (Sweden)

    Yifei Lu

    2017-01-01

    Full Text Available The Internet of Things (IoT has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN, TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

  10. TCP and web browsing performance in case of bi-directional packet loss

    NARCIS (Netherlands)

    Kooij, R.E.; Mei, R.D. van der; Yang, R.

    2010-01-01

    Performance modeling of the transport control protocol (TCP) has received a lot of attention over the past few years. The most commonly quoted results are approximate formulas for TCP throughput (Padhye et al. (2000) [1]) and document download times (Cardwell et al. (2000) [2]) which are used for di

  11. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications.

    Science.gov (United States)

    Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

    2017-01-08

    The Internet of Things (IoT) has gained popularity in recent years. Today's IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem.

  12. DETERMINATION OF 3,5,6-TRICHLORO-2-PYRIDINOL (TCP) BY ELISA

    Science.gov (United States)

    A sensitive, competitive enzyme-linked immunosorbent assay (ELISA) for 3,5,6-trichloro-2pyridinol (TCP) has been developed to quantitate parts per billion (ppb) amounts of the analyte in urine. TCP is a major metabolite and environmental degradation product of the insecticide c...

  13. Functionally graded PCL/ β-TCP biocomposites in a multilayered structure for bone tissue regeneration

    Science.gov (United States)

    Kim, Yong Bok; Kim, GeunHyung

    2012-09-01

    Functionally graded (FG) composites consisting of polycaprolactone (PCL) and beta-tricalcium phosphate ( β-TCP) particles were fabricated with a multilayered structure using a melt plotter with a two-heating-barrel system. Using this process, the concentration of β-TCP particles varied in each layered strut. Scanning electron microscopy (SEM) and energy dispersive spectroscopy mapping of calcium on the fabricated scaffolds indicated that the β-TCP particles were well distributed in each PCL strut, according to conceptual design. By incorporating β-TCP, the FG-PCL/ β-TCP scaffolds had meaningful increases in water absorption (30 % increase) and showed good mechanical properties, although the mechanical properties are slightly low compared to pure PCL/ β-TCP composite. We performed biological assessments to evaluate the capability of these FG scaffolds to act as a biomaterial for bone tissue regeneration with osteoblast-like cells (MG63). SEM images of cell-seeded FG scaffolds showed that the concentrated β-TCP struts were affected as good cell attachment/proliferation sites. Additionally, calcium deposition on the FG scaffolds was higher than that of normal scaffolds after 14 days. In particular, we observed high levels of mineralization in the highly concentrated β-TCP struts in the FG scaffolds. Based on these results, we believe that the FG scaffolds having various spatially designed structures with graded properties will be widely applicable for hard tissue engineering applications.

  14. SDTCP: Towards Datacenter TCP Congestion Control with SDN for IoT Applications

    Science.gov (United States)

    Lu, Yifei; Ling, Zhen; Zhu, Shuhong; Tang, Ling

    2017-01-01

    The Internet of Things (IoT) has gained popularity in recent years. Today’s IoT applications are now increasingly deployed in cloud platforms to perform Big Data analytics. In cloud data center networks (DCN), TCP incast usually happens when multiple senders simultaneously communicate with a single receiver. However, when TCP incast happens, DCN may suffer from both throughput collapse for TCP burst flows and temporary starvation for TCP background flows. In this paper, we propose a software defined network (SDN)-based TCP congestion control mechanism, referred to as SDTCP, to leverage the features, e.g., centralized control methods and the global view of the network, in order to solve the TCP incast problems. When we detect network congestion on an OpenFlow switch, our controller can select the background flows and reduce their bandwidth by adjusting the advertised window of TCP ACK packets of the corresponding background flows so as to reserve more bandwidth for burst flows. SDTCP is transparent to the end systems and can accurately decelerate the rate of background flows by leveraging the global view of the network gained via SDN. The experiments demonstrate that our SDTCP can provide high tolerance for burst flows and achieve better flow completion time for short flows. Therefore, SDTCP is an effective and scalable solution for the TCP incast problem. PMID:28075347

  15. Method to enhance the TCP performance in managed buffer handover for mobile IPv6

    Science.gov (United States)

    Kan, Zhigang; Ma, Jian; Yuan, Man; Luo, Jun

    2002-08-01

    The paper is related to TCP performance enhancement in Buffer Management of Mobile IPv6 where transmission control protocol is used as transport layer protocol. A mechanism that improves TCP performance in buffer management for Mobile IPv6 is proposed when handovers are normally taken place. By this mechanism, MB-aware routers can send

  16. The battle between standards: TCP/IP vs OSI victory through path dependency or by quality?

    NARCIS (Netherlands)

    Maathuis, I.J.H.; Smit, W.A.; Egyedi, T.M.; Krechmer, K.; Jakobs, K.

    2003-01-01

    Between the end of the 1970s and 1994 a fierce competition existed between two possible standards, TCP/IP and OSI, to solve the problem of interoperability of computer networks. Around 1994 it became evident that TCP/IP and not OSI had become the dominant standard. We specifically deal with the ques

  17. Cross-layer TCP Performance Analysis in IEEE 802.11 Vehicular Environments

    Directory of Open Access Journals (Sweden)

    T. Janevski

    2014-06-01

    Full Text Available In this paper we provide a performance analysis of TCP in IEEE 802.11 vehicular environments for different well-known TCP versions, such as Tahoe, Reno, New Reno, Vegas, and Sack. The parameters of interest from the TCP side are the number of Duplicate Acknowledgements - DupAck, and the number of Delayed Acknowledgements - DelAck, while on the wireless network side the analyzed parameter is the interface queue - IFQ. We have made the analysis for the worst-case distance scenario for single-hop and worst-case multihop vehicular environments. The results show that the number of wireless hops in vehicular environments significantly reduces the TCP throughput. The best average performances considering all scenarios were obtained for TCP Vegas. However, the results show that the interface queue at wireless nodes should be at least five packets or more. On the other side, due to shorter distances in the vehicular wireless network, results show possible flexibility of using different values for the DupAck without degradation of the TCP throughput. On the other side, the introduction of the DelAck parameter provides enhancement in the average TCP throughput for all TCP versions.

  18. Robustness of Multiple High Speed TCP CUBIC Connections Under Severe Operating Conditions

    DEFF Research Database (Denmark)

    Pilimon, Artur; Ruepp, Sarah Renée; Berger, Michael Stübert

    2015-01-01

    We study the adaptation capabilities and robustness of the high-speed TCP CUBIC algorithm. For this purpose we consider a network environment with variable and high random packet loss and a large Bandwidth-Delay product, shared by multiple heterogeneous TCP connections. The analysis is based on a...

  19. Adaptive Timer-Based Countermeasures against TCP SYN Flood Attacks

    Science.gov (United States)

    Tanabe, Masao; Akaike, Hirofumi; Aida, Masaki; Murata, Masayuki; Imase, Makoto

    As a result of the rapid development of the Internet in recent years, network security has become an urgent issue. Distributed denial of service (DDoS) attacks are one of the most serious security issues. In particular, 60 percent of the DDoS attacks found on the Internet are TCP attacks, including SYN flood attacks. In this paper, we propose adaptive timer-based countermeasures against SYN flood attacks. Our proposal utilizes the concept of soft-state protocols that are widely used for resource management on the Internet. In order to avoid deadlock, a server releases resources using a time-out mechanism without any explicit requests from its clients. If we change the value of the timer in accordance with the network conditions, we can add more flexibility to the soft-state protocols. The timer is used to manage the resources assigned to half-open connections in a TCP 3-way handshake mechanism, and its value is determined adaptively according to the network conditions. In addition, we report our simulation results to show the effectiveness of our approach.

  20. Improving Quality of Service from TCP/IP Performance Degradation

    Directory of Open Access Journals (Sweden)

    Prof.N..Penchalaiah

    2011-02-01

    Full Text Available TCP is currently the dominate congestion control protocol for the Internet. However, as the Internet evolves into a high-speed wired-cum-wireless hybrid network, performance degradation problems of TCP have appeared, such as underutilizing high-speed links, regarding wireless loss as congestion signal, and unfairness among flows with different RTTs. In order to improve the quality of service for such highspeed hybrid networks, we propose a router-assisted congestion control protocol called Quick Flow Control Protocol (QFCP. The convergence of many traditional services over IPbased infrastructures drastically increases the amount of IP data traffic to be delivered to user clients, thus raising questions about the management of quality of service in such networks. Quality of service will be of primary importance in order to ensure right operation, and to face the occurrence of congestion conditions, due to bandwidth demandingmultimedia services. in this paper, shows that QFCP can significantly shorten flow completion time, fairly allocate bandwidth resource, and be robust to non-congestion related loss. Also we consider a possible scenarios in which multiple multimedia and control streams are conveyed over the same HAN, and study a possible solution for the implementation of an easily manageable QoS framework, that relies on a QoS router based on open source software.

  1. Research on the Congest Control Algorithm of TCP/IP%基于TCP/IP拥塞控制的算法研究

    Institute of Scientific and Technical Information of China (English)

    李学渊

    2005-01-01

    在WPAN上使用TCP的关键在于拥塞控制,根据TCP的拥塞控制机制,通过分析拥塞控制的闭环控制原理、TCP/IP拥塞控制所使用的典型技术,研究TCP/IP拥塞控制在无线网上应用的算法.

  2. TCP/IP Protocol Security and IP Layer Encryption Technology%TCP/IP协议安全与IP层加密技术

    Institute of Scientific and Technical Information of China (English)

    谭兴烈

    2001-01-01

    @@ 由于互联网的广泛使用和TCP/IP协议在全球的风靡,对IP层安全处理技术的研究及在IP层开发的安全产品层出不穷,IP层安全成为一个受到广泛关注的问题,因此研究IP层的安全体系十分重要.TCP/IP协议的安全

  3. Covert Channels Based on the TCP/IP Header Information%基于TCP/IP包头的隐藏通道技术

    Institute of Scientific and Technical Information of China (English)

    杨忠仪; 章正辉

    2006-01-01

    随着信息技术的发展,网络通信安全已经成为安全领域的一个重要内容.本文详细介绍了三种基于TCP/IP包头信息隐蔽传输数据的方法,并就Windows平台阐述了利用TCP/IP包头进行信息隐蔽传输的实现.

  4. 在TMS320DM642上实现嵌入式TCP/IP协议栈%Embedded Solution of TCP/IP Protocol Stack Based on TMS320DM642

    Institute of Scientific and Technical Information of China (English)

    王平; 孙乐美

    2007-01-01

    实现了一个运行在数字信号处理器TMS320DM642上的嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议进行分析,完成基于TCP/IP协议的嵌入式网络系统.

  5. Efficient Frame Schedule Scheme for Real-time Video Transmission Across the Internet Using TCP

    Directory of Open Access Journals (Sweden)

    Yonghua Xiong

    2009-05-01

    Full Text Available The great end-to-end delays are the major factor to influence the visual quality of real-time video across the Internet using TCP as transport layer protocol. In this paper, we present a video frame schedule scheme for rate adaptive real-time video transmission over TCP. The scheme schedules video frames between the application layer sender-buffer, the TCP sender-buffer and TCP receiver-buffer and can regulate automaticlly the video frame rate and play out buffer delays according to the network congestion level. The sheme requires only an extra buffer of application layer and can significantly cut down the end-to-end delays of real-time video without any modification to the network infrastructure or TCP protocol stack. The performance of the proposed solution is evaluated through extensive simulations using the NS-2 simulator.

  6. An Empirical Study on variants of TCP over AODV routing protocol in MANET

    CERN Document Server

    Morshed, Md Monzur; Islam, Md Rafiqul

    2011-01-01

    The cardinal concept of TCP development was to carry data within the network where network congestion plays a vital role to cause packet loss. On the other hand, there are several other reasons to lose packets in Mobile Ad Hoc Networks due to fading, interfaces, multi-path routing, malicious node, and black hole. Along with throughput, fairness of TCP protocols is important to establish a good communication. In this paper, an empirical study has been done by simulation and analysis of TCP variations under AODV routing protocol. In our simulation, we studied multiple variations of TCP, such as Reno, New-Reno, Vegas, and Tahoe. The simulation work has been done in NS2 environment. Based on the analysis simulation result of we carried out our observations with respect to the behavior of AODV routing protocol for different TCP packets under several QoS metrics such as drop, throughput, delay, and jitter.

  7. Characterization and Evaluation of TCP and UDP-based Transport on Real Networks

    Energy Technology Data Exchange (ETDEWEB)

    Cottrell, L.

    2005-01-25

    Standard TCP (Reno TCP) does not perform well on fast long distance networks, due to its AIMD congestion control algorithm. In this paper we consider the effectiveness of various alternatives, in particular with respect to their applicability to a production environment. We then characterize and evaluate the achievable throughput, stability and intra-protocol fairness of different TCP stacks (Scalable, HSTCP, HTCP, Fast TCP, Reno, BICTCP, HSTCP-LP and LTCP) and a UDP based application level transport protocol (UDTv2) on both production and testbed networks. The characterization is made with respect to both the transient traffic (entry and exit of different streams) and the steady state traffic on production Academic and Research networks, using paths with RTTs differing by a factor of 10. We also report on measurements made with 10Gbits/sec NICs with and without TCP Offload Engines, on 10Gbits/s dedicated paths set up for SC2004.

  8. A Novel Onboard-gateway-based Mechanism to Improve TCP Performance in Aeronautical Satellite Networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The IP-based networks on aircraft serve to support Internet services via satellites. However, in aeronautical satellite hybrid networks, the TCP protocol performance often deteriorates due to improper decreases and slow recovery of the congestion window. This paper proposes a window size determination and notification mechanism, onboard-gateway-based mechanism (OGBM), which is based on the onboard gateway in the networks on aircraft. A cross-layer approach is adopted by the onboard gateway to obtain the satellite link bandwidth information. And then, by the gateway, through changing the receiver's advertised window field in ACK packets, TCP sources are notified of the window size of each TCP source calculated on the ground of bandwidth delay product and flow numbers. The mechanism is able to avoid improper changes of TCP window and serve multiple users. Simulation results show that the mechanism with the fairness index close to 1 improves TCP performance in aeronautical satellite networks.

  9. TCP three-way handshake: linking developmental processes with plant immunity.

    Science.gov (United States)

    Lopez, Jessica A; Sun, Yali; Blair, Peter B; Mukhtar, M Shahid

    2015-04-01

    The TCP gene family encodes plant-specific transcription factors involved in growth and development. Equally important are the interactions between TCP factors and other pathways extending far beyond development, as they have been found to regulate a variety of hormonal pathways and signaling cascades. Recent advances reveal that TCP factors are targets of pathogenic effectors and are likely to play a vital role in plant immunity. Our focus is on reviewing the involvement of TCP in known pathways and shedding light on other linkages in the nexus of plant immunity centered around TCP factors with an emphasis on the convergence of effectors, interconnected hormonal networks, utility of the circadian clock, and the potential mechanisms by which pathogen defense may occur.

  10. Application of stochastic discrete event system framework for detection of induced low rate TCP attack.

    Science.gov (United States)

    Barbhuiya, F A; Agarwal, Mayank; Purwar, Sanketh; Biswas, Santosh; Nandi, Sukumar

    2015-09-01

    TCP is the most widely accepted transport layer protocol. The major emphasis during the development of TCP was its functionality and efficiency. However, not much consideration was given on studying the possibility of attackers exploiting the protocol, which has lead to several attacks on TCP. This paper deals with the induced low rate TCP attack. Since the attack is relatively new, only a few schemes have been proposed to mitigate it. However, the main issues with these schemes are scalability, change in TCP header, lack of formal frameworks, etc. In this paper, we have adapted the stochastic DES framework for detecting the attack, which addresses most of these issues. We have successfully deployed and tested the proposed DES based IDS on a test bed.

  11. Effect of β-TCP Ceramic on the Total Protein of Osteoblasts

    Institute of Scientific and Technical Information of China (English)

    QI Zhitao; DAI Honglian; ZHANG qihuan; CAO Xianying; LI Shipu

    2007-01-01

    The osteoblast with the β-TCP ceramic was co-cultured. Scanning electron microscopy shows the cells adhered onto β-TCP ceramic surface and grew better, proving the β-TCP ceramic has a biocompatible property. The Coomassie brilliant blue G-250 stain shows that the total protein in the experimental groups was highly increased compared with the control group (p<0.05). Flow-cytometric analysis shows that β-TCP ceramic could promote the osteoblast transform from the G0/G1 phase to S phase. Those all demonstrate the product of the degradation of the β-TCP ceramic may take part in the protein metabolism of osteoblast.

  12. Model Based System Engineering Approach of a Lightweight Embedded TCP/IP

    Directory of Open Access Journals (Sweden)

    M. Z. Rashed

    2011-04-01

    Full Text Available The use of embedded software is growing very rapidly. Accessing the internet is a necessaryservice which has large range of applications in many fields. The Internet is based on TCP/IPwhich is a very important stack. Although TCP/IP is very important there is not a softwareengineering model describing it. The common method in modeling and describing TCP/IP is RFCswhich is not sufficient for software engineer and developers. Therefore there is a need for softwareengineering approach to help engineers and developers to customize their own web basedapplications for embedded systems.This research presents a model based system engineering approach of lightweight TCP/IP. Themodel contains the necessary phases for developing a lightweight TCP/IP for embedded systems.The proposed model is based on SysML as a model based system engineering language.

  13. PERFORMANCE ANALYSIS OF ROUTING PROTOCOLS AND TCP VARIANTS UNDER HTTP AND FTP TRAFFIC IN MANETS

    Directory of Open Access Journals (Sweden)

    Ghassan A. QasMarrogy

    2014-12-01

    Full Text Available MANET stands for mobile ad-hoc network that has multi-hop and dynamic nature, where each station changes its location frequently and automatically configures itself. In this paper, four routing protocols that are OLSR, GRP, DSR, and AODV are discussed along with three TCP variants that are SACK, New Reno and Reno. The main focus of this paper is to study the impact scalability, mobility and traffic loads on routing protocols and TCP variants. The paper results shows that the proactive protocols OLSR and GRP outperform the reactive protocols AODV and DSR with the same nodes size, nodes speed, and traffic load. On the other hand, the TCP variants research reveal the superiority of the TCP SACK variant over the other two variants in case of adapting to varying network size, while the TCP Reno variant acts more robustly in varying mobility speeds and traffic loads

  14. Evaluation of replacement protocols and modifications to TCP to enhance ASC Wide Area Network performance.

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Randy L. Jr.

    2004-09-01

    Historically, TCP/IP has been the protocol suite used to transfer data throughout the Advanced Simulation and Computing (ASC) community. However, TCP was developed many years ago for an environment very different from the ASC Wide Area Network (WAN) of today. There have been numerous publications that hint of better performance if modifications were made to the TCP algorithms or a different protocol was used to transfer data across a high bandwidth, high delay WAN. Since Sandia National Laboratories wants to maximize the ASC WAN performance to support the Thor's Hammer supercomputer, there is strong interest in evaluating modifications to the TCP protocol and in evaluating alternatives to TCP, such as SCTP, to determine if they provide improved performance. Therefore, the goal of this project is to test, evaluate, compare, and report protocol technologies that enhance the performance of the ASC WAN.

  15. Calorimetry investigations of milled α-tricalcium phosphate (α-TCP) powders to determine the formation enthalpies of α-TCP and X-ray amorphous tricalcium phosphate.

    Science.gov (United States)

    Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

    2015-09-01

    One α-tricalcium phosphate (α-TCP) powder was either calcined at 500°C to obtain fully crystalline α-TCP or milled for different durations to obtain α-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71wt.% ATCP and up to 2.0±0.1wt.% β-TCP as minor phase were then hydrated in 0.1M Na2HPO4 aqueous solution and the resulting heat flows were measured by isothermal calorimetry. Additionally, the evolution of the phase composition during hydration was determined by in situ XRD combined with the G-factor method, an external standard method which facilitates the indirect quantification of amorphous phases. Maximum ATCP hydration was reached after about 1h, while that of crystalline α-TCP hydration occurred between 4 and 11h, depending on the ATCP content. An enthalpy of formation of -4065±6kJ/mol (T=23°C) was calculated for ATCP (Ca3(PO4)2), while for crystalline α-TCP (α-Ca3(PO4)2) a value of -4113±6kJ/mol (T=23°C) was determined. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Identification and Transcript Analysis of the TCP Transcription Factors in the Diploid Woodland Strawberry Fragaria vesca

    Science.gov (United States)

    Wei, Wei; Hu, Yang; Cui, Meng-Yuan; Han, Yong-Tao; Gao, Kuan; Feng, Jia-Yue

    2016-01-01

    Plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, and PROLIFERATING CELL FACTORS (TCP) transcription factors play versatile functions in multiple processes of plant growth and development. However, no systematic study has been performed in strawberry. In this study, 19 FvTCP genes were identified in the diploid woodland strawberry (Fragaria vesca) accession Heilongjiang-3. Phylogenetic analysis suggested that the FvTCP genes were classified into two main classes, with the second class further divided into two subclasses, which was supported by the exon-intron organizations and the conserved motif structures. Promoter analysis revealed various cis-acting elements related to growth and development, hormone and/or stress responses. We analyzed FvTCP gene transcript accumulation patterns in different tissues and fruit developmental stages. Among them, 12 FvTCP genes exhibited distinct tissue-specific transcript accumulation patterns. Eleven FvTCP genes were down-regulated in different fruit developmental stages, while five FvTCP genes were up-regulated. Transcripts of FvTCP genes also varied with different subcultural propagation periods and were induced by hormone treatments and biotic and abiotic stresses. Subcellular localization analysis showed that six FvTCP-GFP fusion proteins showed distinct localizations in Arabidopsis mesophyll protoplasts. Notably, transient over-expression of FvTCP9 in strawberry fruits dramatically affected the expression of a series of genes implicated in fruit development and ripening. Taken together, the present study may provide the basis for functional studies to reveal the role of this gene family in strawberry growth and development. PMID:28066489

  17. Hierarchical structures of β-TCP/45S5 bioglass hybrid scaffolds prepared by gelcasting.

    Science.gov (United States)

    Lopes, João Henrique; Magalhães, Jéssica Aparecida; Gouveia, Rubia Figueredo; Bertran, Celso Aparecido; Motisuke, Mariana; Camargo, Samira E A; Trichês, Eliandra de Sousa

    2016-09-01

    This paper investigates the microstructure and the mechanical properties of β-tricalcium phosphate (β-TCP) three-dimensional (3D) porous materials reinforced with 45S5 bioactive glass (BG). β-TCP and β-TCP/x%-BG scaffolds with interconnected pores networks, suitable for bone regeneration, were fabricated by gel-casting method. Mechanical properties, porosity, and morphological characteristics were evaluated by compressive strength test, scanning electron microscopy (SEM) and X-ray microtomography analysis, whereas the structures were fully explored by XRD, and Raman spectroscopy. To the best of our knowledge, this is the first time where the mechanism for understanding the effect of bioglass on the mechanical properties and microstruture of β-TCP/45S5-BG scaffolds has been systematically studied. The findings showed that ionic product lixiviated from 45S5 bioactive glass, rich in silicon species and sodium ion, catalyzes a phase transition from β-TCP to Si-TCP by replacement of phosphorus for silicon and contributes to the improvement of scaffolds mechanical properties. The compressive strength of β-TCP/5%-BG and β-TCP/7.5%-BG was improved around 200% in comparison to pure β-TCP. Osteoblast-like cells (MG 63) were exposed to the materials for 24h through the use of medium conditioned by β-tricalcium phosphate/bioactive glass. Cell viability was measured by MTT assay in the cells and the data obtained were submitted to ANOVA, Tukey׳s multiple comparison (pTCP/7.5-BG promoted an increase of cell proliferation. The results suggest that compositions and processing method studied may provide appropriate materials for tissue engineering.

  18. The Putative O-Linked N-Acetylglucosamine Transferase SPINDLY Inhibits Class I TCP Proteolysis to Promote Sensitivity to Cytokinin.

    Science.gov (United States)

    Steiner, Evyatar; Livne, Sivan; Kobinson-Katz, Tammy; Tal, Lior; Pri-Tal, Oded; Mosquna, Assaf; Tarkowská, Danuše; Mueller, Bruno; Tarkowski, Petr; Weiss, David

    2016-06-01

    Arabidopsis (Arabidopsis thaliana) SPINDLY (SPY) is a putative serine and threonine O-linked N-acetylglucosamine transferase (OGT). While SPY has been shown to suppress gibberellin signaling and to promote cytokinin (CK) responses, its catalytic OGT activity was never demonstrated and its effect on protein fate is not known. We previously showed that SPY interacts physically and functionally with TCP14 and TCP15 to promote CK responses. Here, we aimed to identify how SPY regulates TCP14/15 activities and how these TCPs promote CK responses. We show that SPY activity is required for TCP14 stability. Mutation in the putative OGT domain of SPY (spy-3) stimulated TCP14 proteolysis by the 26S proteasome, which was reversed by mutation in CULLIN1 (CUL1), suggesting a role for SKP, CUL1, F-box E3 ubiquitin ligase in TCP14 proteolysis. TCP14 proteolysis in spy-3 suppressed all TCP14 misexpression phenotypes, including the enhanced CK responses. The increased CK activity in TCP14/15-overexpressing flowers resulted from increased sensitivity to the hormone and not from higher CK levels. TCP15 overexpression enhanced the response of the CK-induced synthetic promoter pTCS to CK, suggesting that TCP14/15 affect early steps in CK signaling. We propose that posttranslational modification of TCP14/15 by SPY inhibits their proteolysis and that the accumulated proteins promote the activity of the CK phosphorelay cascade in developing Arabidopsis leaves and flowers.

  19. Preparation and Characterization ofβ-TCP/CS Scaffolds by Freeze-extraction and Freeze-gelation

    Institute of Scientific and Technical Information of China (English)

    HAO Ruiran; WANG Deping; YAO Aihua; HUANG Wenhai

    2011-01-01

    The freeze-extraction and freeze-gelation methods were used to prepare highly porous β-TCP/CS scaffolds with different β-TCP/CS ratio. In these methods, the suspending mixture of β-TCP and chitosan was frozen, the frozen mixture was immersed in a non-solvent(0.05 mol/L NaOH/ehanol aqueous) bath to allow the exchange between solvent(acetic-acid aqueous) and non-solvent at a temperature lower than the freezing point of the acetic-acid. Then, the β-TCP/CS scaffolds were formed and dried at room temperature. Scanning electron microscopy (SEM), X-ray diffraction (XRD), gas chromatography (GC) and omnipotence material testing machine were employed to characterize theβ-TCP/CS scaffolds. The results of GC show that the freeze extraction of the β-TCP/chitosan scaffolds was completed when the extraction time is above 24 h. The SEM results show that the β-TCP/CS scaffolds are composed of interconnected pore network. The porosity of the β-TCP/CS scaffolds decrease with the increase of the content of the β-TCP. The β-TCP/CS scaffolds have a highest compressive strength when the chitosan/β-TCP ratio is 30:70. The present work displays that the β-TCP/CS composite scaffolds with appropriate mechanical properties and high porosity can be successfully prepared by the freeze-extraction and freeze-gelation methods.

  20. The use of TCP based EUD to rank and compare lung radiotherapy plans: in-silico study to evaluate the correlation between TCP with physical quality indices.

    Science.gov (United States)

    Chaikh, Abdulhamid; Balosso, Jacques

    2017-06-01

    To apply the equivalent uniform dose (EUD) radiobiological model to estimate the tumor control probability (TCP) scores for treatment plans using different radiobiological parameter settings, and to evaluate the correlation between TCP and physical quality indices of the treatment plans. Ten radiotherapy treatment plans for lung cancer were generated. The dose distributions were calculated using anisotropic analytical algorithm (AAA). Dose parameters and quality indices derived from dose volume histograms (DVH) for target volumes were evaluated. The predicted TCP was computed using EUD model with tissue-specific parameter (a=-10). The assumed radiobiological parameter setting for adjuvant therapy [tumor dose to control 50% of the tumor (TCD50) =36.5 Gy and γ50=0.72] and curative intent (TCD50=51.24 Gy and γ50=0.83) were used. The bootstrap method was used to estimate the 95% confidence interval (95% CI). The coefficients (ρ) from Spearman's rank test were calculated to assess the correlation between quality indices with TCP. Wilcoxon paired test was used to calculate P value. The 95% CI of TCP were 70.6-81.5 and 46.6-64.7, respectively, for adjuvant radiotherapy and curative intent. The TCP outcome showed a positive and good correlation with calculated dose to 95% of the target volume (D95%) and minimum dose (Dmin). Consistently, TCP correlate negatively with heterogeneity indices. This study confirms that more relevant and robust radiobiological parameters setting should be integrated according to cancer type. The positive correlation with quality indices gives chance to improve the clinical out-come by optimizing the treatment plans to maximize the Dmin and D95%. This attempt to increase the TCP should be carried out with the respect of dose constraints for organs at risks. However, the negative correlation with heterogeneity indices shows that the optimization of beam arrangements could be also useful. Attention should be paid to obtain an appropriate

  1. Evaluation of collagen/heparin coated TCP/HA granules for long-term delivery of BMP-2.

    Science.gov (United States)

    Hannink, Gerjon; Geutjes, Paul J; Daamen, Willeke F; Buma, Pieter

    2013-02-01

    Bone morphogenetic proteins (BMPs) are the most potent osteoinductive growth factors. However, a delivery system is essential to take advantage of the osteoinductive effect of BMPs. The purpose of this study was to develop a sustained delivery system for recombinant human bone morphogenetic protein-2 (BMP-2). We covalently attached heparin to a cross-linked collagen type I coated tricalciumphosphate/hydroxyapatite (TCP/HA) bone substitute and subsequently loaded it with BMP-2. To systematically evaluate the contribution of each component with respect to the binding and release of BMP-2, six constructs were prepared and characterized: TCP/HA, TCP/HA with collagen (TCP/HACol), and TCP/HA with collagen and heparin (TCP/HAColHep) with and without BMP-2 (B). More BMP-2 bound to the TCP/HAColHep + B (92.9 ± 4.8 ng BMP-2/mg granule) granules as compared to the TCP/HACol + B (69.0 ± 9.6 ng BMP-2/mg granule) and TCP/HA + B granules (62.9 ± 5.4 ng BMP-2/mg granule). No difference in release pattern was found between the TCP/HA + B and TCP/HACol + B granules. Up to day 14, BMP-2 was still bound to the TCP/HAColHep + B granules, whereas most BMP had been released from TCP/HACol + B and TCP/HA + B granules at that time. After 21 days most BMP-2 also had been released from the TCP/HAColHep + B granules. The local and sustained delivery system for BMP-2 developed in this study may be useful as a carrier for BMP-2 and could possibly enhance bone regeneration efficacy for the treatment of large bone defects.

  2. Light-weight TCP/IP stack based on wireless embedded system%基于无线嵌入式系统的轻量级TCP/IP协议栈

    Institute of Scientific and Technical Information of China (English)

    吕俊龙; 陈春燕; 和卫星

    2010-01-01

    提出了一种基于小型无线嵌入式系统的轻量级TCP/IP协议栈CW_TCP/IP(compact wireless-TCP/IP).CW-TCP/IP使用适于小型嵌入式系统的简单数据结构调用CCB(connection control block)来处理TCP/IP,它创建TCP/IP头文件时不需参考其它数据结构,可以采用TCP Veno拥塞控制算法来提高其无线性能.该协议栈具有很高的便携性,因此可开发为处理器和独立的操作系统,目前它可以移植到Linux系统.通过实验对适用于小型嵌入式操作系统的CW-TCP/IP、Linux TCP/IP和μC/TCP-IP的性能进行了比较,比较的结果表明了CW-TCP/IP具有卓越的无线性能.

  3. 基于TCP Vegas拥塞控制算法的研究与改进%Improvement and Research on Congestion Control Algorithm of TCP Vegas

    Institute of Scientific and Technical Information of China (English)

    谢怡宁; 孙广路; 苏洁; 翟继强

    2011-01-01

    网络拥塞已经成为制约因特网发展的瓶颈.在众多TCP拥塞控制算法中,TCP Vegas表现出比其他算法更为优越的性能,但是在特定环境下也存在不足.本文通过对网络拥塞策略的研究和Vegas性能的分析,验证了Vegas整体性能优于Reno的结论,并通过分析Vegas的特点,针对α和β的值对公平性的影响,提出了一种在TCP Vegas与TCP Reno共存环境下获得良好拥塞控制的方法,并通过网络仿真证明了本方法的有效性和正确性.%Network congestion has become a bottleneck restricting the development of the Internet. Among the TCP congestion control algorithm,TCP Vegas shows more than the other algorithms superior performance. However, in certain circumstances there are disadvantages. Based on the strategy of network congestion and Vegas performance analysis, validation of the overall performance is better than Reno' s conclusion. By analyzing the characteristics of Vegas for the a and β value on the fairness of this paper, a TCP Vegas and TCP Reno for good co-existence environment,congestion control,and network simulation proves the validity and accuracy of this method.

  4. Matching references with MEDLINE via TCP/IP.

    Science.gov (United States)

    Guidi, J N

    1993-01-01

    Bibliographic references are an important part of databases and information resources used by clinicians and biomedical researchers. In addition to the obvious clerical advantages of standard references, bibliographic references can also be used as links to related items in different data sets. This paper describes an effort that involved matching references from a variety of disparate databases to canonical MEDLINE references. The references matched were those involved in a database unification project which is part of the Mouse Genome Informatics effort at The Jackson Laboratory. Software was developed to take advantage of a commercially available retrieval engine which accesses MEDLINE on CD-ROM disks. The software permits client programs on UNIX/C, and potentially other environments, to access unabridged MEDLINE via networks supporting the TCP/IP protocols. The matching process described can be used as a model for similar efforts with different research or clinical data sets, as well as different hardware or software environments.

  5. Poly (γ-glutamic acid)/beta-TCP nanocomposites via in situ copolymerization: Preparation and characterization.

    Science.gov (United States)

    Shu, Xiu-Lin; Shi, Qing-Shan; Feng, Jin; Yang, Yun-Hua; Zhou, Gang; Li, Wen-Ru

    2016-07-01

    A series biodegradable poly (γ-glutamic acid)/beta-tricalcium phosphate (γ-PGA/TCP) nanocomposites were prepared which were composed of poly-γ-glutamic acid polymerized in situ with β-tricalcium phosphate and physiochemically characterized as bone graft substitutes. The particle size via dynamic light scattering, the direct morphological characterization via transmission electron microscopy and field emission scanning electron microscope, which showed that γ-PGA and β-TCP were combined compactly at 80℃, and the γ-PGA/TCP nanocomposites had homogenous and nano-sized grains with narrow particle size distributions. The water uptake and retention abilities, in vitro degradation properties, cytotoxicity in the simulated medium, and protein release of these novel γ-PGA/TCP composites were investigated. Cell proliferation in composites was nearly twice than β-TCP when checked in vitro using MC3T3 cell line. We also envision the potential use of γ-PGA/TCP systems in bone growth factor or orthopedic drug delivery applications in future bone tissue engineering applications. These observations suggest that the γ-PGA/TCP are novel nanocomposites with great potential for application in the field of bone tissue engineering.

  6. Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area.

    Science.gov (United States)

    Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

    2016-01-01

    Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications.

  7. Magnesium incorporation into β-TCP reduced its in vivo resorption by decreasing parathormone production.

    Science.gov (United States)

    Yassuda, Debora H; Costa, Neusa F M; Fernandes, Gustavo O; Alves, Gutemberg G; Granjeiro, José M; Soares, Glória de A

    2013-07-01

    Beta-tricalcium phosphate (β-TCP), one of the most widely used bioresorbable materials for bone therapy, can be doped with magnesium ions, generating β-TCMP. The objectives of this work were to evaluate, on a murine dental alveolus grafting model, the biocompatibility of β-TCP and β-TMCP granules by histomorphometric analysis, as well as the impact on plasmatic levels of receptor activator of nuclear factor κB ligand (RANK-L), osteoprotegerin (OPG), osteocalcin, osteopontin, and parathormone (PTH) during bone repair, using Luminex multiplexing technology. After grafting for 42 days, β-TCP grafted group presented higher bioresorption and induced more newly formed bone than β-TCMP (p TCP grafting also induced higher plasmatic levels of RANK-L, compared to β-TCMP and control (blood clot) groups at 21st day (p TCP by the 42nd day (p TCP group and attained a peak on the 21st day. In conclusion, β-TCP granules were more bioresorbable and osteogenic than β-TCMP granules, and the resorption of both materials might have been affected by osteoclastogenesis modulated by changes in the plasmatic levels of PTH and RANK-L.

  8. Comparative phylogenomic analysis provides insights into TCP gene functions in Sorghum.

    Science.gov (United States)

    Francis, Aleena; Dhaka, Namrata; Bakshi, Mohit; Jung, Ki-Hong; Sharma, Manoj K; Sharma, Rita

    2016-12-05

    Sorghum is a highly efficient C4 crop with potential to mitigate challenges associated with food, feed and fuel. TCP proteins are of particular interest for crop improvement programs due to their well-demonstrated roles in crop domestication and shaping plant architecture thereby, affecting agronomic traits. We identified 20 TCP genes from Sorghum. Except SbTCP8, all are either intronless or contain introns in the untranslated regions. Comparative phylogenetic analysis of Arabidopsis, rice, Brachypodium and Sorghum TCP proteins revealed two distinct classes categorized into ten sub-clades. Sub-clade F is dicot-specific, whereas A2, G1 and I1 groups only contained genes from grasses. Sub-clade B was missing in Sorghum, whereas group A1 was missing in rice indicating species-specific divergence of TCP proteins. TCP proteins of Sorghum are enriched in disorder promoting residues with class I containing higher percent disorder than class II proteins. Seven pairs of paralogous TCP genes were identified from Sorghum, five of which seem to predate Rice-Sorghum divergence. All of them have diverged in their expression. Based on the expression and orthology analysis, five Sorghum genes have been shortlisted for further investigation for their roles in regulating plant morphology. Whereas, three genes have been identified as candidates for engineering abiotic stress tolerance.

  9. Models of TCP in high-BDP environments and their experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Vardoyan, G. [University of Massachusetts; Rao, Nageswara S [ORNL; Towlsey, D. [University of Massachusetts

    2016-01-01

    In recent years, the computer networking community has seen a steady growth in bandwidth-delay products (BDPs). Several TCP variants were created to combat the shortcomings of legacy TCP when it comes to operation in high-BDP environments. These variants, among which are CUBIC, STCP, and H-TCP, have been extensively studied in some empirical contexts, and some analytical models exist for CUBIC and STCP. However, since these studies have been conducted, BDPs have risen even more, and new bulk data transfer tools have emerged that utilize multiple parallel TCP streams. In view of these new developments, it is imperative to revisit the question: Which congestion control algorithms are best adapted to current networking environments? In order to help resolve this question, we contribute the following: (i) using first principles, we develop a general throughput-prediction framework that takes into account buffer sizes and maximum window constraints; (ii) we validate the models using measurements and achieve low prediction errors; (iii) we note differences in TCP dynamics between two experimental configurations and find one of them to be significantly more deterministic than the other; we also find that CUBIC and H-TCP outperform STCP, especially when multiple streams are used; and (iv) we present preliminary results for modelling multiple TCP streams for CUBIC and STCP.

  10. TCP with header checksum option for wireless links: An analytical approach towards performance evaluation

    Indian Academy of Sciences (India)

    Pawan Kumar Gupta; Joy Kuri

    2007-06-01

    TCP performs poorly in wireless mobile networks due to large bit error rates. Basically, the TCP sender responds to these losses as if they were due to congestion in the network, and reduces the congestion window unnecessarily. In earlier work, it has been shown that adding a TCP header checksum is very useful in differentiating between congestion loss and corruption loss. With the modified TCP, receivers can explicitly indicate corruption of received packets by generating “Explicit Loss Notifications (ELNs).” This paper focuses on an analytical study of this modified TCP protocol. We derive an expression for the probability of a receiver generating successful ELN, assuming a generic link layer protocol for data transfer over wireless links. Next, we develop an analytical approach for TCP throughput evaluation under the modified scheme. We compare the throughput results obtained by analysis and simulation, and find very close agreement between the two sets. We also compare the performance of the modified scheme with the standard NewReno TCP, and find considerable improvement in data throughput over wireless links.

  11. Application of Azolla for 2, 4, 6-Trichlorophenol (TCP Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Zazouli

    2013-11-01

    Full Text Available Background & Aims of the Study: The 2, 4, 6-Trichlorophenol (TCP is a phenolic compound which it can produce adverse effects on human and environment. Therefore, the removal of these compounds is necessary. The aim of this study is the investigation of TCP removal by using Azolla filiculoides biomass. Materials & Methods: The Azolla biomass was dried in the sunlight, and then it was crushed and sieved to particle sizes in range of 1-2 mm. Next treated with 0.1M HCl for a period of 5h. The Azolla was washed with distilled water and it was used as adsorbent. The effect of operating parameters such as pH, contact time, TCP concentration and adsorbent dose on the TCP removal efficiency was investigated. The residues concentration of TCP was measured by spectrophotometer in λ max of 296 nm. Results: In optimum condition (pH 3, contact time 120 min , adsorbent dose 10 gr/l and TCP concentration 10 ppm, Azolla was able to remove 95% of TCP from aqueous solutions. The equilibrium data follows the Langmuir isotherm and the proper kinetic model is pseudo-second model. Conclusions: Adsorption process by Azolla filiculoides is an efficient method for removal of 2, 4, 6-Trichlorophenol from aqueous solutions.

  12. Osteogenesis Capacity of a Novel BMP/α-TCP Bioactive Composite Bone Cement

    Institute of Scientific and Technical Information of China (English)

    YANG Wei-zhong; ZHOU Da-li; YIN Shao-ya; YIN Guang-fu; GAO Li-da; ZHANG Yun

    2004-01-01

    To improve the osteogenesis ability of α-tricalcium phosphate (α-TCP) bone cement,a novel BMP/α-TCP composite bone cement was prepared.By measuring the setting time and compressive strength,the hydration characteristic of bone cement was evaluated.Animal experiments including histological observation,radiographic investigation as well as digital image analyses reveal the difference of osteogenesis ability among BMP,α-TCP bone cement and BMP/α-TCP composite bone cement.Results show that α-TCP bone cement possesses excellent hydration and setting properties as well as high mechanical property.Comparison experiments show that BMP/α-TCP composite bone cement has a stronger osteogenesis ability.The gross observation of the implant site does not exhibit any inflammation or necrosis.Histological analyses reveal that the material has good osteointegration with host bone,and new bone formation is detected within the materials,which are degrading.Strong osteogenesis ability of the composite is due to not only the excellent osteoconductive potential but also the osteoinductive potential contributed by active BMP releasing and the material degradation.Large skull defect could be well-healed by filling BMP/α-TCP composite bone cement.This novel material proves itself to be an absorbable and bioactive bone cement with an osteogenesis ability.

  13. Fair and Efficient TCP Access in the IEEE 802.11 Infrastructure Basic Service Set

    CERN Document Server

    Keceli, Feyza; Ayanoglu, Ender

    2008-01-01

    When the stations in an IEEE 802.11 infrastructure Basic Service Set (BSS) employ Transmission Control Protocol (TCP) in the transport layer, this exacerbates per-flow unfair access which is a direct result of uplink/downlink bandwidth asymmetry in the BSS. We propose a novel and simple analytical model to approximately calculate the per-flow TCP congestion window limit that provides fair and efficient TCP access in a heterogeneous wired-wireless scenario. The proposed analysis is unique in that it considers the effects of varying number of uplink and downlink TCP flows, differing Round Trip Times (RTTs) among TCP connections, and the use of delayed TCP Acknowledgment (ACK) mechanism. Motivated by the findings of this analysis, we design a link layer access control block to be employed only at the Access Point (AP) in order to resolve the unfair access problem. The novel and simple idea of the proposed link layer access control block is employing a congestion control and filtering algorithm on TCP ACK packets...

  14. Improving TCP Throughput Using Modified Packet Reordering Technique (MPRT Over Manets

    Directory of Open Access Journals (Sweden)

    Prakash B. Khelage

    2014-08-01

    Full Text Available at the beginning of development of network technology TCP transport agent were designed assuming that communication is using wired network, but recently there is huge demand and use of wireless networks for communication. Those TCP variants which are successful in wired networks are neither able to detect exact causes of packet losses nor unnecessary transmission delays over wireless networks. The biggest challenge over MANET is design of robust and reliable TCP variant which should give best performance in different network scenarios. Till date more than dozens of TCP variants designed and modified by researcher and scientist communities even though the level of TCP performance have to be optimum in different scenarios, Such as congestion, link failure, signal loss and interferences. Over rod, grid and bulk network model also. As some of TCP-variant performs well in particular network scenarios but degrades in other scenarios. The objective of this research work, to modify packet reordering technique based TCP variant, implement and compare its performance with other variants. Validation of basic and main network model done using network simulator (NS2 and calculated throughput, delay and packet drop by processing trace files. The simulated result shows that, proposed technique performs outstanding almost in all network scenarios with minimum packet losses and minimum delay.

  15. Genomewide analysis of TCP transcription factor gene family in Malus domestica

    Indian Academy of Sciences (India)

    Ruirui Xu; Peng Sun; Fengjuan Jia; Longtao Lu; Yuanyuan Li; Shizhong Zhang; Jinguang Huang

    2014-12-01

    Teosinte branched1/cycloidea/proliferating cell factor1 (TCP) proteins are a large family of transcriptional regulators in angiosperms. They are involved in various biological processes, including development and plant metabolism pathways. In this study, a total of 52 TCP genes were identified in apple (Malus domestica) genome. Bioinformatic methods were employed to predicate and analyse their relevant gene classification, gene structure, chromosome location, sequence alignment and conserved domains of MdTCP proteins. Expression analysis from microarray data showed that the expression levels of 28 and 51 MdTCP genes changed during the ripening and rootstock–scion interaction processes, respectively. The expression patterns of 12 selected MdTCP genes were analysed in different tissues and in response to abiotic stresses. All of the selected genes were detected in at least one of the tissues tested, and most of them were modulated by adverse treatments indicating that the MdTCPs were involved in various developmental and physiological processes. To the best of our knowledge, this is the first study of a genomewide analysis of apple TCP gene family. These results provide valuable information for studies on functions of the TCP transcription factor genes in apple.

  16. TCP-friendliness Analysis and Evaluation for TCP-like IVS Flow Control Algorithm%TCP-like IVS流量控制算法TCP友好性的模拟评价和分析

    Institute of Scientific and Technical Information of China (English)

    贺凯健; 林亚平

    2002-01-01

    TCP-like IVS流量控制算法是对IVS流量控制算法的改进,提高了数据流稳定性和减小数据流抖动.文章研究TCP-like ⅣS流与TCP流争抢带宽资源中的TCP友好性问题.通过理论分析和模拟实验指出TCP-1ikeIVS流TCP友好性差的原因,提出未来改进的方向,为深入研究英特网上视频会议系统的QoS保证打下基础.

  17. Bone engineering by phosphorylated-pullulan and β-TCP composite.

    Science.gov (United States)

    Takahata, Tomohiro; Okihara, Takumi; Yoshida, Yasuhiro; Yoshihara, Kumiko; Shiozaki, Yasuyuki; Yoshida, Aki; Yamane, Kentaro; Watanabe, Noriyuki; Yoshimura, Masahide; Nakamura, Mariko; Irie, Masao; Van Meerbeek, Bart; Tanaka, Masato; Ozaki, Toshifumi; Matsukawa, Akihiro

    2015-11-20

    A multifunctional biomaterial with the capacity bond to hard tissues, such as bones and teeth, is a real need for medical and dental applications in tissue engineering and regenerative medicine. Recently, we created phosphorylated-pullulan (PPL), capable of binding to hydroxyapatite in bones and teeth. In the present study, we employed PPL as a novel biocompatible material for bone engineering. First, an in vitro evaluation of the mechanical properties of PPL demonstrated both PPL and PPL/β-TCP composites have higher shear bond strength than materials in current clinical use, including polymethylmethacrylate (PMMA) cement and α-tricalcium phosphate (TCP) cement, Biopex-R. Further, the compressive strength of PPL/β-TCP composite was significantly higher than Biopex-R. Next, in vivo osteoconductivity of PPL/β-TCP composite was investigated in a murine intramedular injection model. Bone formation was observed 5 weeks after injection of PPL/β-TCP composite, which was even more evident at 8 weeks; whereas, no bone formation was detected after injection of PPL alone. We then applied PPL/β-TCP composite to a rabbit ulnar bone defect model and observed bone formation comparable to that induced by Biopex-R. Implantation of PPL/β-TCP composite induced new bone formation at 4 weeks, which was remarkably evident at 8 weeks. In contrast, Biopex-R remained isolated from the surrounding bone at 8 weeks. In a pig vertebral bone defect model, defects treated with PPL/β-TCP composite were almost completely replaced by new bone; whereas, PPL alone failed to induce bone formation. Collectively, our results suggest PPL/β-TCP composite may be useful for bone engineering.

  18. The enzyme toxicity and genotoxicity of chlorpyrifos and its toxic metabolite TCP to zebrafish Danio rerio.

    Science.gov (United States)

    Wang, Jun; Wang, Jinhua; Zhu, Lusheng; Xie, Hui; Shao, Bo; Hou, Xinxin

    2014-12-01

    Chlorpyrifos is a broad-spectrum organophosphorus insecticide (O,O-diethyl -O-3,5,6-trichloro-2-pyridyl phosphorothioate) that is used in numerous agricultural and urban pest controls. The primary metabolite of chlorpyrifos is 3,5,6-trichloro pyridine-2-phenol (TCP). Because of its strong water solubility and mobility, this harmful metabolite exists in the environment in a large amount. Although TCP has potentially harmful effects on organisms in the environment, few studies have addressed TCP pollution. Therefore, this study was undertaken to investigate the effect of chlorpyrifos and TCP on the microsomal cytochrome P450 content in the liver, on the activity of NADPH-P450 reductase and antioxidative enzymes [catalase (CAT) and superoxide dismutase (SOD)], and on reactive oxygen species (ROS) generation and DNA damage in zebrafish. Male and female zebrafish were separated and exposed to a control solution and three concentrations of chlorpyrifos (0.01, 0.1, 1 mg L(-1)) and TCP (0.01, 0.1, 0.5 mg L(-1)), respectively, sampled after 5, 10, 15, 20 and 25 days. The results indicated that the P450 content and the NADPH-P450 reductase and antioxidative enzyme (CAT and SOD) activities could be induced by chlorpyrifos and TCP. DNA damage of zebrafish was enhanced with increasing chlorpyrifos and TCP concentrations. Meanwhile, chlorpyrifos and TCP induced a significant increase of ROS generation in the zebrafish hepatopancreas. In conclusion, this study proved that chlorpyrifos (0.01-1 mg L(-1)) and TCP (0.01-0.5 mg L(-1)) are both highly toxic to zebrafish.

  19. ALP gene expression in cDNA samples from bone tissue engineering using a HA/TCP/Chitosan scaffold

    Science.gov (United States)

    Stephanie, N.; Katarina, H.; Amir, L. R.; Gunawan, H. A.

    2017-08-01

    This study examined the potential use of hydroxyapatite (HA)/tricalcium phosphate (TCP)/Chitosan as a bone tissue engineering scaffold. The potential for using HA/TCP/chitosan as a scaffold was analyzed by measuring expression of the ALP osteogenic gene in cDNA from bone biopsies from four Macaque nemestrina. Experimental conditions included control (untreated), treatment with HA/TCP 70:30, HA/TCP 50:50, and HA/TCP/chitosan. cDNA samples were measured quantitively with Real-Time PCR (qPCR) and semi-quantitively by gel electrophoresis. There were no significant differences in ALP gene expression between treatment subjects after two weeks, but the HA/TCP/chitosan treatment gave the highest level of expression after four weeks. The scaffold using the HA/TCP/chitosan combination induced a higher level of expression of the osteogenic gene ALP than did scaffold without chitosan.

  20. Si-TCP Synthesized from "Mg-free" Reagents Employed as Calcium Phosphate Cement

    OpenAIRE

    Mariana Motisuke; Raul García Carrodeguas; Cecília Amélia Carvalho Zavaglia

    2012-01-01

    The influence of silicon doping on calcium phosphate cement were explored in this work. α-TCP and Si-α-TCP were prepared by solid state reaction employing "Mg-free" CaHPO4, CaCO3 and CaSiO3 as precursors. It was possible to obtain TCP powders with low contents of β phase as contaminant. Cement liquid phase was an aqueous solution containing 2.5 wt. (%) of Na2HPO4 and 1.5 wt. (%) of citric acid. The liquid-to-powder ratio was 0.6 mL.g-1. Chemical, physical and mechanical propert...

  1. A New Route for Preparation of β-TCP/PLLA Composite

    Institute of Scientific and Technical Information of China (English)

    Feng ZHANG; Fang MEI; Xin Zhi WANG; Xiao Yang HU; Yong Ming LUO; Xu Liang DENG

    2006-01-01

    A new facile route for preparation of β-TCP/PLLA composites is reported in this letter.SEM images display that β-TCP particles with average diameter of 400 nm were well bonded and distributed within the pore walls of the PLLA scaffolds. The mixture of the novel complex and human dental pulp cells was transplanted subcutaneously into the dorsal surface of a nude mouse.Two months later histological examination showed that new collagen and new dentin formed.The results revealed that the new nano β-TCP/PLLA composite combined with human pulp cells could induce dentin formation, offering a new way to dental tissue engineering.

  2. TCP/IP协议在计算机网络中的应用

    Institute of Scientific and Technical Information of China (English)

    付登刚

    2016-01-01

    网络发展的基础就是TCP/IP协议,属于网络协议的一种类型,目前,我们日常生活中使用的计算机协议,TCP/IP协议可以实现计算机的网络互连,但是,安全漏洞在TCP/IP协议中也是广泛存在的,本文主要针对TCP/IP协议的应用及其安全漏洞进行分析.

  3. Evaluation of the biotissue of PCL and {beta}-TCP; Avaliacao de um biotecido de PCL e {beta}-TCP

    Energy Technology Data Exchange (ETDEWEB)

    Solomao, Zenaide; Zavaglia, Cecilia A.C., E-mail: zavagl@fem.unicamp.br [Universidade Estadual de Campinas (DEMa/FEM/LABIOMEC/INCT), Campinas, SP (Brazil). Biofabris; Dias, Carmen G.B.T. [Universidade Federal do Para - FEM/ITEC-UFPA, Belem, PA (Brazil)

    2011-07-01

    The use of biomaterials to replace, repair injured tissues and organs of human beings has increased due to population growth and its higher life expectancy. The tissue engineering is an interdisciplinary field that integrates principles of biology, chemistry, genetics, materials science and biomedical engineering, to produce composite three-dimensional, capable of replacing biological tissues. The development of new biomaterials using the method of evaporation of the solvent can help to solvent this problem. This work aimed to characterized the membranes of poly ({epsilon}-caprolactone) dense and porous (scaffolds) of PCL/B-TCP; and make an in vitro evaluation. Techniques were used to: SEM, EDS, XRD, TGA, DSC, mechanical traction tests, test cell viability and activity of alkaline phosphatase (ALP). The hydrolytic degradation was analyzed in phosphate buffer (PBS) and the biocompatibility through standards (ASTM and ABNT) concluding that the materials are biocompatible and are used with great potential for replacement of the bone tissue. (author)

  4. Effects of MgO modified β-TCP nanoparticles on the microstructure and properties of β-TCP/Mg-Zn-Zr composites

    Directory of Open Access Journals (Sweden)

    H.R. Zheng

    2017-03-01

    Full Text Available The mechanical properties and corrosion resistance of magnesium alloy composites were improved by the addition of MgO surface modified tricalcium phosphate ceramic nanoparticles (m-β-TCP. Mg-3Zn-0.8Zr composites with unmodified (MZZT and modified (MZZMT nanoparticles were produced by high shear mixing technology. Effects of MgO m-β-TCP nanoparticles on the microstructure, mechanical properties, electrochemical corrosion properties and cytocompatibility of Mg-Zn-Zr/β-TCP composites were investigated. After hot extrusion deformation and dynamic recrystallization, the grain size of MZZMT was the half size of MZZT and the distribution of m-β-TCP particles in the matrix was more uniform than β-TCP particles. The yield tensile strength (YTS, ultimate tensile strength (UTS, and corrosion potential (Ecorr of MZZMT were higher than MZZT; the corrosion current density (Icorr of MZZMT was lower than MZZT. Cell proliferation of co-cultured MZZMT and MZZT composite samples were roughly the same and the cell number at each time point is higher for MZZMT than for MZZT samples.

  5. Genome-Wide Identification and Characterization of BrrTCP Transcription Factors in Brassica rapa ssp. rapa

    Directory of Open Access Journals (Sweden)

    Jiancan Du

    2017-09-01

    Full Text Available The teosinte branched1/cycloidea/proliferating cell factor (TCP gene family is a plant-specific transcription factor that participates in the control of plant development by regulating cell proliferation. However, no report is currently available about this gene family in turnips (Brassica rapa ssp. rapa. In this study, a genome-wide analysis of TCP genes was performed in turnips. Thirty-nine TCP genes in turnip genome were identified and distributed on 10 chromosomes. Phylogenetic analysis clearly showed that the family was classified as two clades: class I and class II. Gene structure and conserved motif analysis showed that the same clade genes have similar gene structures and conserved motifs. The expression profiles of 39 TCP genes were determined through quantitative real-time PCR. Most CIN-type BrrTCP genes were highly expressed in leaf. The members of CYC/TB1 subclade are highly expressed in flower bud and weakly expressed in root. By contrast, class I clade showed more widespread but less tissue-specific expression patterns. Yeast two-hybrid data show that BrrTCP proteins preferentially formed heterodimers. The function of BrrTCP2 was confirmed through ectopic expression of BrrTCP2 in wild-type and loss-of-function ortholog mutant of Arabidopsis. Overexpression of BrrTCP2 in wild-type Arabidopsis resulted in the diminished leaf size. Overexpression of BrrTCP2 in triple mutants of tcp2/4/10 restored the leaf phenotype of tcp2/4/10 to the phenotype of wild type. The comprehensive analysis of turnip TCP gene family provided the foundation to further study the roles of TCP genes in turnips.

  6. Structural and Catalytic Differences between Two FADH2-Dependent Monooxygenases: 2,4,5-TCP 4-Monooxygenase (TftD from Burkholderia cepacia AC1100 and 2,4,6-TCP 4-Monooxygenase (TcpA from Cupriavidus necator JMP134

    Directory of Open Access Journals (Sweden)

    ChulHee Kang

    2012-08-01

    Full Text Available 2,4,5-TCP 4-monooxygenase (TftD and 2,4,6-TCP 4-monooxygenase (TcpA have been discovered in the biodegradation of 2,4,5-trichlorophenol (2,4,5-TCP and 2,4,6-trichlorophenol (2,4,6-TCP. TcpA and TftD belong to the reduced flavin adenine dinucleotide (FADH2-dependent monooxygenases and both use 2,4,6-TCP as a substrate; however, the two enzymes produce different end products. TftD catalyzes a typical monooxygenase reaction, while TcpA catalyzes a typical monooxygenase reaction followed by a hydrolytic dechlorination. We have previously reported the 3D structure of TftD and confirmed the catalytic residue, His289. Here we have determined the crystal structure of TcpA and investigated the apparent differences in specificity and catalysis between these two closely related monooxygenases through structural comparison. Our computational docking results suggest that Ala293 in TcpA (Ile292 in TftD is possibly responsible for the differences in substrate specificity between the two monooxygenases. We have also identified that Arg101 in TcpA could provide inductive effects/charge stabilization during hydrolytic dechlorination. The collective information provides a fundamental understanding of the catalytic reaction mechanism and the parameters for substrate specificity. The information may provide guidance for designing bioremediation strategies for polychlorophenols, a major group of environmental pollutants.

  7. Structural and catalytic differences between two FADH(2)-dependent monooxygenases: 2,4,5-TCP 4-monooxygenase (TftD) from Burkholderia cepacia AC1100 and 2,4,6-TCP 4-monooxygenase (TcpA) from Cupriavidus necator JMP134.

    Science.gov (United States)

    Hayes, Robert P; Webb, Brian N; Subramanian, Arun Kumar; Nissen, Mark; Popchock, Andrew; Xun, Luying; Kang, Chulhee

    2012-01-01

    2,4,5-TCP 4-monooxygenase (TftD) and 2,4,6-TCP 4-monooxygenase (TcpA) have been discovered in the biodegradation of 2,4,5-trichlorophenol (2,4,5-TCP) and 2,4,6-trichlorophenol (2,4,6-TCP). TcpA and TftD belong to the reduced flavin adenine dinucleotide (FADH(2))-dependent monooxygenases and both use 2,4,6-TCP as a substrate; however, the two enzymes produce different end products. TftD catalyzes a typical monooxygenase reaction, while TcpA catalyzes a typical monooxygenase reaction followed by a hydrolytic dechlorination. We have previously reported the 3D structure of TftD and confirmed the catalytic residue, His289. Here we have determined the crystal structure of TcpA and investigated the apparent differences in specificity and catalysis between these two closely related monooxygenases through structural comparison. Our computational docking results suggest that Ala293 in TcpA (Ile292 in TftD) is possibly responsible for the differences in substrate specificity between the two monooxygenases. We have also identified that Arg101 in TcpA could provide inductive effects/charge stabilization during hydrolytic dechlorination. The collective information provides a fundamental understanding of the catalytic reaction mechanism and the parameters for substrate specificity. The information may provide guidance for designing bioremediation strategies for polychlorophenols, a major group of environmental pollutants.

  8. Research and Development of Industrial Real-time TCP/IP Protocol Stack%工业实时TCP/IP协议栈的研究与开发

    Institute of Scientific and Technical Information of China (English)

    韦安; 刘国平

    2005-01-01

    指出了通用TCP/IP协议用于工业控制存在的不足,通过对标准TCP/IP协议栈的简化,并加入自行开发的协议,开发了NETCON-TCP工业以太网控制协议,较好地解决了TCP/IP应用于实际控制中所存在的主要问题,详细描述了协议栈开发的细节.最后对比了NETCON-TCP和LINUX-TCP的实时性,验证了NETCON-TCP协议具有实时性好、体积小、可靠性较高的优点.

  9. Research TCP/IP Network Communication Programming on Java Socket%JAVA TCP/IP Socket网络通信编程研究

    Institute of Scientific and Technical Information of China (English)

    戴歆

    2013-01-01

    First Java is a programming language for Internet. network Communication is the advantage of Java language. Using TCP/IP communication protocol in the program development is to realize the C/S model of point to point communication net-work. This thesis focuses on the study of Java Socket network programming framework and network communication program implementation in C/S mode.%Java最初是一种网络编程语言网络通信是Java语言的优势,在程序开发中利用TCP/IP通信协议则能实现C/S模式下的点对点的网络通信。该文主要研究在C/S模式下使用Java Socket实现TCP/IP网络程序框架及网络通信的程序实现。

  10. Synthesis of bioactive β-TCP coatings with tailored physico-chemical properties on zirconia bioceramics.

    Science.gov (United States)

    Stefanic, Martin; Milacic, Radmila; Drazic, Goran; Škarabot, Miha; Budič, Bojan; Krnel, Kristoffer; Kosmač, Tomaž

    2014-10-01

    The objective of this work was to develop a synthesis procedure for the deposition of β-TCP coatings with tailored physico-chemical properties on zirconia bioceramics. The synthesis procedure involved two steps: (i) a rapid wet-chemical deposition of a biomimetic CaP coating and (ii) a subsequent post-deposition processing of the biomimetic CaP coating, which included a heat treatment between 800 and 1200 °C, followed by a short sonication in a water bath. By regulating the heating temperature the topography of the β-TCP coatings could be controlled. The average surface roughness (Ra) ranged from 42 nm for the coating that was heated at 900 °C (TCP-900) to 630 nm for the TCP-1200 coating. Moreover, the heating temperature also affected the dissolution rate of the coatings in a physiological solution, their protein-adsorption capacity and their bioactivity in a simulated body fluid.

  11. Si-TCP synthesized from "Mg-free" reagents employed as calcium phosphate cement

    Directory of Open Access Journals (Sweden)

    Mariana Motisuke

    2012-08-01

    Full Text Available The influence of silicon doping on calcium phosphate cement were explored in this work. α-TCP and Si-α-TCP were prepared by solid state reaction employing "Mg-free" CaHPO4, CaCO3 and CaSiO3 as precursors. It was possible to obtain TCP powders with low contents of β phase as contaminant. Cement liquid phase was an aqueous solution containing 2.5 wt. (% of Na2HPO4 and 1.5 wt. (% of citric acid. The liquid-to-powder ratio was 0.6 mL.g-1. Chemical, physical and mechanical properties of the cement samples were determined by means of XRD, FTIR, XRF, compressive strength and SEM. The calcium phosphate cements obtained achieved satisfactory properties; however, Si-α-TCP presented a decrease on the rate of setting reaction.

  12. Comparative Performance Evaluation of TCP Variants in WiMAX (and WLANs Network Configurations

    Directory of Open Access Journals (Sweden)

    Konstantinos Tsiknas

    2012-01-01

    Full Text Available An important application for the IEEE 802.16 technology (also called WiMAX is to provide high-speed access to the Internet where the transmission control protocol (TCP is the core transport protocol. In this paper we study through extensive simulation scenarios the performance characteristics of five representative TCP schemes, namely, TCP New Reno, Vegas, Veno, Westwood, and BIC, in WiMAX (and WLANs networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities, and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control and suggest the best schemes to be employed in WiMAX networks.

  13. TCP/IP网络通信协议的实现与探讨

    Institute of Scientific and Technical Information of China (English)

    张凯

    2008-01-01

    TCP/IP协议(Transmissiorl Control Protocol/Internet Protocol)是目前最成功的网络通信协议,它被用于当今所构筑的最大的开放式网络系统Internet之上就是其成功的证明.TCP/IP协议具有广泛的兼容性和可伸缩性,可连接不同的计算机网络协议、不同的网络设备.TCP/IP事实上己成为网络互联的标准,并成为支持Internet/Intranet的协议标淮.本文就是针对当前流行的TCP/IP网络通信协议的实现进行了具体的研究和探讨.

  14. {beta}-TCP porous pellets as an orthopaedic drug delivery system: ibuprofen/carrier physicochemical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Baradari, Hiba; Damia, Chantal; Dutreih-Colas, Maggy; Champion, Eric; Chulia, Dominique; Viana, Marylene, E-mail: hiva.baradari@etu.unilim.fr [SPCTS-Centre Europeen de la Ceramique, 12 Rue Atlantis, 87068 Limoges CEDEX (France)

    2011-10-15

    Calcium phosphate bone substitute materials can be loaded with active substances for in situ, targeted drug administration. In this study, porous {beta}-TCP pellets were investigated as an anti-inflammatory drug carrier. Porous {beta}-TCP pellets were impregnated with an ethanolic solution of ibuprofen. The effects of contact time and concentration of ibuprofen solution on drug adsorption were studied. The ibuprofen adsorption equilibrium time was found to be one hour. The adsorption isotherms fitted to the Freundlich model, suggesting that the interaction between ibuprofen and {beta}-TCP is weak. The physicochemical characterizations of loaded pellets confirmed that the reversible physisorption of ibuprofen on {beta}-TCP pellets is due to Van der Waals forces, and this property was associated with the 100% ibuprofen release.

  15. An adaptive mechanism to guarantee the bandwidth fairness of TCP flows

    Institute of Scientific and Technical Information of China (English)

    张顺亮; 叶澄清

    2004-01-01

    End-to-end TCP (transmission control protocol) congestion control can cause unfairness among multiple TCP connections with different RTT (Round Trip Time). The throughput of TCP connection is inversely proportional to its RTT. To resolve this problem, researchers have proposed many methods. The existing proposals for RTT-aware conditioner work well when congestion level is low. However, they over-protect long RTT flows and starve short RTT flows when congestion level is high. Due to this reason, an improved method based on adaptive thought is proposed. According to the congestion level of networks, the mechanism can adaptively adjust the degree of the protection to long RTT flows. Extensive simulation experiments showed that the proposed mechanism can guarantee the bandwidth fairness of TCP flows effectively and outperforms the existing methods.

  16. Comparative study of microstructural remodification to porous β-TCP and HA in rabbits

    Institute of Scientific and Technical Information of China (English)

    SUN Jiao; SHEN QingYi; LU JianXi

    2009-01-01

    emodeling pattern resulted from bone formation and scaffold resorption was significantly different for the two bioceramics.The results demonstrated that the 75% porous β-TCP was more suitable for new bone remodification than HA scaffold.

  17. An adaptive mechanism to guarantee the bandwidth fairness of TCP flows

    Institute of Scientific and Technical Information of China (English)

    张顺亮; 叶澄清

    2004-01-01

    End-to-end TCP(transmission control protocol)congestion control can cause unfairness among multiple TCP connections with different RTT(Round Trip Time). The throughput of TCP connection is inversely proportional to its RTT.To resolve this problem,researchers have proposed many methods. The existing proposals for RTT-aware conditioner work well when congestion level is low. However,they over-protect long RTT flows and starve short RTT flows when congestion level is high. Due to this reason,an improved method based on adaptive thought is proposed. According to the congestion level of networks,the mechanism can adaptively adjust the degree of the protection to long RTT flows. Extensive simulation experiments showed that the proposed mechanism can guarantee the bandwidth fairness of TCP flows effectively and outperforms the existing methods.

  18. SM_TCP: a new reliable multicast transport protocol for satellite IP networks

    Science.gov (United States)

    Liu, Gongliang; Gu, Xuemai; Li, Shizhong

    2005-11-01

    A new reliable multicast transport protocol SM_TCP is proposed for satellite IP networks in this paper. In SM_TCP, the XOR scheme with the aid of on-board buffering and processing is used for error recovery and an optimal retransmission algorithm is designed, which can reduce the recovery time by half of the RTT and minimize the number of retransmissions. In order to avoid the unnecessary decrease of congestion window in the high BER satellite channels, the occupied buffer sizes at bottlenecks are measured in adjusting the congestion window, instead of depending on the packet loss information. The average session rate of TCP sessions and of multicast sessions passing through the satellite are also measured and compared in adjusting the congestion window, which contributes to bandwidth fairness. Analysis and simulation results show fairness with TCP flows and scalability.

  19. 关于TCP/IP协议分析和应用研究

    Institute of Scientific and Technical Information of China (English)

    万焱

    2015-01-01

    作为大国与最大发展中国家的在新时期担负着建设现代化TCP/IP协议和社会主义新中国的伟大责任,应当借助生物技术、信息技术等高新技术的有效支持,注重加速发展。TCP/IP协议面临着不少的分析问题。为此,本文阐述了TCP/IP协议分析,以及解决TCP/IP协议面临分析的应用研究。

  20. Reducing Communication Overhead by Scheduling TCP Transfers on Mobile Devices using Wireless Network Performance Maps

    DEFF Research Database (Denmark)

    Højgaard-Hansen, Kim; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2012-01-01

    The performance of wireless communication networks has been shown to have a strong location dependence. Measuring the performance while having accurate location information available makes it possible to generate performance maps. In this paper we propose a framework for the generation and use...... of such performance maps. We demonstrate how the framework can be used to reduce the retransmissions and to better utilise network resources when performing TCP-based file downloads in vehicular M2M communication scenarios. The approach works on top of a standard TCP stack hence has to map identified transmission...... intervals to predicted TCP data volumes. The file download optimisation is evaluated using extensive simulations comparing the TCP scheduling approach to a normal transfer. The performance map is generated by capturing round-trip time measurements and a threshold approach for the mean value for a given area...

  1. TCP performance evaluation over AODV and DSDV in RW and SN mobility models

    Institute of Scientific and Technical Information of China (English)

    REN Wei; YEUNG D.Y.; JIN Hai

    2006-01-01

    This paper presents evaluation and comparison of the TCP performance in different mobile scenarios generated by Random Waypoint (RW) and Social Network (SN) mobility models. To our knowledge, TCP performance in SN mobility is discussed for the first time. The impact of AODV and DSDV routing protocols on the TCP goodput, delay and drop rate performance is also discussed. Extensive simulation results and analysis showed that TCP has better performance over AODV than over DSDV and has more stable performance in SN mobility than in RW mobility. We suggest using more mobility models, in particular, such as SN, in the evaluations of the transport layer or routing layer protocols because the mobility patterns have impacts on the protocol performance.

  2. IMPLEMENTASI PROTOKOL TCP/IP UNTUK PENGENDALIAN KOMPUTER JARAK JAUH

    Directory of Open Access Journals (Sweden)

    Rudy Adipranata

    2002-01-01

    Full Text Available This day, computer networking has become important necessity for data exchange between computers. And along with the growing of number of computer in a network, the difficulty for managing that network also increased. Because of that reality, in this paper will be build application for remote controlling computer using TCP/IP protocol. This application build using Delphi 5.0 programming language and dWinsock 2.75, component interface for Windows Socket API which is created especially for Delphi language, and separate to two sub applications, namely server application, which run on computer to be controlled and the secondly is client application, run on controller computer. In this application, data text or binary will be send, so two pair components will be used : TTextServer - TTextClient and TBinaryServer- TBinaryClient. The functions which implemented in this applications are : lock and unlock computer, reboot, shutdown, execute remote program, send message, capture screen and view remote programs. Test is doing on internal network and internet network, and the result of that test for internal network, all of functions can be activated perfectly without significant delay (less than 1 second. But for internet network, there is delay, which the number variable depend on data traffic at that moment. Abstract in Bahasa Indonesia : Sekarang ini jaringan komputer sudah menjadi suatu kebutuhan yang sangat penting untuk mempermudah pertukaran data antar komputer. Dan seiring dengan makin berkembangnya jumlah komputer pada suatu jaringan, maka makin bertambah pula tingkat kesulitan untuk mengelola jaringan tersebut. Oleh sebab itu pada penelitian ini akan dibuat aplikasi untuk mengendalikan komputer secara jarak jauh dengan menggunakan protokol TCP/IP. Aplikasi ini dibuat dengan menggunakan bahasa pemrograman Delphi 5.0 dan dWinsock 2.75 yang merupakan komponen antar muka Windows Socket API yang dikhususkan untuk bahasa pemrograman Delphi, dan terdiri

  3. Fermi-LAT detection of the Galactic nova TCP J18102829-2729590

    Science.gov (United States)

    Li, Kwan-Lok; Chomiuk, Laura

    2016-11-01

    Fermi-LAT detection of the Galactic nova TCP J18102829-2729590 Following the discovery of the nova in Sagittarius TCP J18102829-2729590 (CBAT 2016 10 20.383; ATel #9658), we triggered an one-week Fermi ToO (observation number: 090603-1-1; PI: Laura Chomiuk) from 2016-10-25 as part of our Fermi-LAT monitoring campaign for Galactic novae (ATel #9311).

  4. Biofabrication of a PLGA-TCP-based porous bioactive bone substitute with sustained release of icaritin.

    Science.gov (United States)

    Xie, Xin-Hui; Wang, Xin-Luan; Zhang, Ge; He, Yi-Xin; Leng, Yang; Tang, Ting-Ting; Pan, Xiaohua; Qin, Ling

    2015-08-01

    A phytomolecule, icaritin, has been identified and shown to be osteopromotive for the prevention of osteoporosis and osteonecrosis. This study aimed to produce a bioactive poly (l-lactide-co-glycolide)-tricalcium phosphate (PLGA-TCP)-based porous scaffold incorporating the osteopromotive phytomolecule icaritin, using a fine spinning technology. Both the structure and the composition of icaritin-releasing PLGA-TCP-based scaffolds were evaluated by scanning electron microscopy (SEM). The porosity was quantified by both water absorption and micro-computed tomography (micro-CT). The mechanical properties were evaluated using a compression test. In vitro release of icaritin from the PLGA-TCP scaffold was quantified by high-performance liquid chromatography (HPLC). The attachment, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the composite scaffold were evaluated. Both an in vitro cytotoxicity test and an in vivo test via muscular implantation were conducted to confirm the scaffold's biocompatibility. The results showed that the PLGA-TCP-icaritin composite scaffold was porous, with interconnected macro- (about 480 µm) and micropores (2-15 µm). The mechanical properties of the PLGA-TCP-icaritin scaffold were comparable with those of the pure PLGA-TCP scaffold, yet was spinning direction-dependent. Icaritin content was detected in the medium and increased with time. The PLGA-TCP-icaritin scaffold facilitated the attachment, proliferation and osteogenic differentiation of BMSCs. In vitro cytotoxicity test and in vivo intramuscular implantation showed that the composite scaffold had no toxicity with good biocompatibility. In conclusion, an osteopromotive phytomolecule, icaritin, was successfully incorporated into PLGA-TCP to form an innovative porous composite scaffold with sustained release of osteopromotive icaritin, and this scaffold had good biocompatibility and osteopromotion, suggesting its potential for orthopaedic

  5. Osteointegration of PLGA implants with nanostructured or microsized β-TCP particles in a minipig model.

    Science.gov (United States)

    Kulkova, Julia; Moritz, Niko; Suokas, Esa O; Strandberg, Niko; Leino, Kari A; Laitio, Timo T; Aro, Hannu T

    2014-12-01

    Bioresorbable suture anchors and interference screws have certain benefits over equivalent titanium-alloy implants. However, there is a need for compositional improvement of currently used bioresorbable implants. We hypothesized that implants made of poly(l-lactide-co-glycolide) (PLGA) compounded with nanostructured particles of beta-tricalcium phosphate (β-TCP) would induce stronger osteointegration than implants made of PLGA compounded with microsized β-TCP particles. The experimental nanostructured self-reinforced PLGA (85L:15G)/β-TCP composite was made by high-energy ball-milling. Self-reinforced microsized PLGA (95L:5G)/β-TCP composite was prepared by melt-compounding. The composites were characterized by gas chromatography, Ubbelohde viscometry, scanning electron microscopy, laser diffractometry, and standard mechanical tests. Four groups of implants were prepared for the controlled laboratory study employing a minipig animal model. Implants in the first two groups were prepared from nanostructured and microsized PLGA/β-TCP composites respectively. Microroughened titanium-alloy (Ti6Al4V) implants served as positive intra-animal control, and pure PLGA implants as negative control. Cone-shaped implants were inserted in a random order unilaterally in the anterior cortex of the femoral shaft. Eight weeks after surgery, the mechanical strength of osteointegration of the implants was measured by a push-out test. The quality of new bone surrounding the implant was assessed by microcomputed tomography and histology. Implants made of nanostructured PLGA/β-TCP composite did not show improved mechanical osteointegration compared with the implants made of microsized PLGA/β-TCP composite. In the intra-animal comparison, the push-out force of two PLGA/β-TCP composites was 35-60% of that obtained with Ti6Al4V implants. The implant materials did not result in distinct differences in quality of new bone surrounding the implant.

  6. Fabrication of individual alginate-TCP scaffolds for bone tissue engineering by means of powder printing.

    Science.gov (United States)

    Castilho, Miguel; Rodrigues, Jorge; Pires, Inês; Gouveia, Barbara; Pereira, Manuel; Moseke, Claus; Groll, Jürgen; Ewald, Andrea; Vorndran, Elke

    2015-01-06

    The development of polymer-calcium phosphate composite scaffolds with tailored architectures and properties has great potential for bone regeneration. Herein, we aimed to improve the functional performance of brittle ceramic scaffolds by developing a promising biopolymer-ceramic network. For this purpose, two strategies, namely, direct printing of a powder composition consisting of a 60:40 mixture of α/β-tricalcium phosphate (TCP) powder and alginate powder or vacuum infiltration of printed TCP scaffolds with an alginate solution, were tracked. Results of structural characterization revealed that the scaffolds printed with 2.5 wt% alginate-modified TCP powders presented a uniformly distributed and interfusing alginate TCP network. Mechanical results indicated a significant increase in strength, energy to failure and reliability of powder-modified scaffolds with an alginate content in the educts of 2.5 wt% when compared to pure TCP, as well as to TCP scaffolds containing 5 wt% or 7.5 wt% in the educts, in both dry and wet states. Culture of human osteoblast cells on these scaffolds also demonstrated a great improvement of cell proliferation and cell viability. While in the case of powder-mixed alginate TCP scaffolds, isolated alginate gels were formed between the calcium phosphate crystals, the vacuum-infiltration strategy resulted in the covering of the surface and internal pores of the TCP scaffold with a thin alginate film. Furthermore, the prediction of the scaffolds' critical fracture conditions under more complex stress states by the applied Mohr fracture criterion confirmed the potential of the powder-modified scaffolds with 2.5 wt% alginate in the educts as structural biomaterial for bone tissue engineering.

  7. TCP/IP Communication System for Controlling a Vehicular Traffic Intersection

    Directory of Open Access Journals (Sweden)

    Pedraza-Martínez Luis Fernando

    2013-10-01

    Full Text Available This paper describes the development of a prototype of a vehicular traffic controller, whose system of communication is based on the TCP/IP protocol, in order to re- motely monitor and control the operation of traffic lights for a vehicular intersection. The results show the times of communication between the central and the traffic controller. The conclusions highlight the importance of using the TCP/IP protocol in traffic light systems.

  8. The Predigest Project of TCP/IP Protocol Communication System Based on DSP Technology and Ethernet

    Science.gov (United States)

    hong-you, Wang; san-ping, Zhao

    The paper introduce a predigest project of TCP/IP based on DSP CMOS chip TMS320F2407 and Ethernet interface. The system design the Network Interface Controller using TMS320F2407and TRL8019AS,it simplify TCP/IP, achieve simple protocol stack in DSP, and achieve Data transmission by software program. The experiment indicated that, the communication system constructed by TMS320F2407andTRL8019AS is low cast, simple and reliable.

  9. ATM QoS Experiments Using TCP Applications: Performance of TCP/IP Over ATM in a Variety of Errored Links

    Science.gov (United States)

    Frantz, Brian D.; Ivancic, William D.

    2001-01-01

    Asynchronous Transfer Mode (ATM) Quality of Service (QoS) experiments using the Transmission Control Protocol/Internet Protocol (TCP/IP) were performed for various link delays. The link delay was set to emulate a Wide Area Network (WAN) and a Satellite Link. The purpose of these experiments was to evaluate the ATM QoS requirements for applications that utilize advance TCP/IP protocols implemented with large windows and Selective ACKnowledgements (SACK). The effects of cell error, cell loss, and random bit errors on throughput were reported. The detailed test plan and test results are presented herein.

  10. Application of the Embedded TCP/IP Protocol by DSP%嵌入式TCP/IP协议栈在DSP上的实现

    Institute of Scientific and Technical Information of China (English)

    倪秀胜

    2006-01-01

    介绍了TMS320C5402芯片与RTL8019AS互联网控制器的硬件接口电路的设计,实现了一个运行在TMS320C5402上的小型嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议、ICMP协议进行分析,完成了基于TCP/IP协议的嵌入式网络系统.

  11. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus

    Science.gov (United States)

    Harn, Tony; Spielman, Ingrid; Gao, Yang; Kovacikova, Gabriela; Biais, Nicolas

    2016-01-01

    Type IV pilus (T4P) systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP) is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system. PMID:27992883

  12. The Vibrio cholerae Minor Pilin TcpB Initiates Assembly and Retraction of the Toxin-Coregulated Pilus.

    Directory of Open Access Journals (Sweden)

    Dixon Ng

    2016-12-01

    Full Text Available Type IV pilus (T4P systems are complex molecular machines that polymerize major pilin proteins into thin filaments displayed on bacterial surfaces. Pilus functions require rapid extension and depolymerization of the pilus, powered by the assembly and retraction ATPases, respectively. A set of low abundance minor pilins influences pilus dynamics by unknown mechanisms. The Vibrio cholerae toxin-coregulated pilus (TCP is among the simplest of the T4P systems, having a single minor pilin TcpB and lacking a retraction ATPase. Here we show that TcpB, like its homolog CofB, initiates pilus assembly. TcpB co-localizes with the pili but at extremely low levels, equivalent to one subunit per pilus. We used a micropillars assay to demonstrate that TCP are retractile despite the absence of a retraction ATPase, and that retraction relies on TcpB, as a V. cholerae tcpB Glu5Val mutant is fully piliated but does not induce micropillars movements. This mutant is impaired in TCP-mediated autoagglutination and TcpF secretion, consistent with retraction being required for these functions. We propose that TcpB initiates pilus retraction by incorporating into the growing pilus in a Glu5-dependent manner, which stalls assembly and triggers processive disassembly. These results provide a framework for understanding filament dynamics in more complex T4P systems and the closely related Type II secretion system.

  13. Congestion Control in TCP/AQM Networks Using a Disturbance Observer

    Science.gov (United States)

    Kubo, Ryogo; Kani, Junichi; Fujimoto, Yukihiro

    This paper presents a novel congestion controller for transmission control protocol/active queue management (TCP/AQM) networks. In order to maintain the queue length to a value less than the buffer size at the aggregation nodes, the queue management mechanism drops some packets depending on the probability calculated by a congestion controller. However, conventional controllers such as random early detection (RED) algorithms and proportional-integral-derivative (PID)-based controllers are not compatible with parameter variation in TCP/AQM networks. Parameter variation in TCP/AQM networks includes the change of the number of TCP connections, the inflow of user datagram protocol (UDP) flows and so on. In the proposed method, the effect of parameter variation is estimated as drop probability disturbance by using a disturbance observer (DOB). By using the DOB, disturbance suppression characteristics of the controlled system can be drastically improved. In addition, the TCP/AQM network system is analyzed on the basis of an acceleration control scheme. The proposed method is validated by simulation studies performed using a nonlinear model of a TCP/AQM network and verifications made using the network simulator ns-2.

  14. The effect of Tricresyl-Phosphate (TCP) as an additive on wear of Iron (Fe)

    Science.gov (United States)

    Ghose, Hiren M.; Ferrante, John; Honecy, Frank C.

    1987-01-01

    The effect of tricresyl phosphate (TCP) as an antiwear additive in lubricant trimethyol propane triheptanoate (TMPTH) was investigated. The objective was to examine step loading wear by use of surface analysis, wetting, and chemical bonding changes in the lubricant. The investigation consisted of steploading wear studies by a pin or disk tribometer, the effects on wear related to wetting by contact angle and surface tension measurements of various liquid systems, the chemical bonding changes between lubricant and TCP chromatographic analysis, and by determining the reaction between the TCP and metal surfaces through wear scar analysis by Auger emission spectroscopy (AES). The steploading curve for the base fluid alone shows rapid increase of wear rate with load. The steploading curve for the base fluid in presence of 4.25 percent by volume TCP under dry air purge has shown a great reduction of wear rate with all loads studied. It has also been found that the addition of 4.25 percent by volume TCP plus 0.33 percent by volume water to the base lubricant under N2 purge also greatly reduces the wear rate with all loads studied. AES surface analysis reveals a phosphate type wear resistant film, which greatly increases load-bearing capacity, formed on the iron disk. Preliminary chromatographic studies suggest that this film forms either because of ester oxidation or TCP degradation. Wetting studies show direct correlation between the spreading coefficient and the wear rate.

  15. Development of bioactive porous α-TCP/HAp beads for bone tissue engineering.

    Science.gov (United States)

    Asaoka, Teruo; Ohtake, Shoji; Furukawa, Katsuko S; Tamura, Akito; Ushida, Takashi

    2013-11-01

    Porous beads of bioactive ceramics such as hydroxyapatite (HAp) and tribasic calcium phosphate (TCP) are considered a promising scaffold for cultivating bone cells. To realize this, α-TCP/HAp functionally graded porous beads are fabricated with two main purposes: to maintain the function of the scaffold with sufficient strength up to the growth of new bone, and is absorbed completely after the growth. HAp is a bioactive material that has both high strength and strong tissue-adhesive properties, but is not readily absorbed by the human body. On the contrary, α-TCP is highly bioabsorbable, resulting in a scaffold that is absorbed before it is completely replaced by bone. In this study, we produced porous, bead-shaped carriers as scaffolds for osteoblast culture. To control the solubility in vivo, the fabricated beads contained α-TCP at the center and HAp at the surface. Cell adaptability of these beads for bone tissue engineering was confirmed in vitro. It was found that α-TCP/HAp bead carriers exhibit low toxicity in the initial stages of cell seeding and cell adhesion. The presence of HAp in the composite bead form effectively increased ALP activity. In conclusion, it is suggested that these newly developed α-TCP/HAp beads are a promising tool for bone tissue engineering.

  16. Analysis of the TCP genes expressed in the inflorescence of the orchid Orchis italica.

    Science.gov (United States)

    De Paolo, Sofia; Gaudio, Luciano; Aceto, Serena

    2015-11-04

    TCP proteins are plant-specific transcription factors involved in many different processes. Because of their involvement in a large number of developmental pathways, their roles have been investigated in various plant species. However, there are almost no studies of this transcription factor family in orchids. Based on the available transcriptome of the inflorescence of the orchid Orchis italica, in the present study we identified 12 transcripts encoding TCP proteins. The phylogenetic analysis showed that they belong to different TCP classes (I and II) and groups (PCF, CIN and CYC/TB1), and that they display a number of conserved motifs when compared with the TCPs of Arabidopsis and Oryza. The presence of a specific cleavage site for the microRNA miRNA319, an important post-transcriptional regulator of several TCP genes in other species, was demonstrated for one transcript of O. italica, and the analysis of the expression pattern of the TCP transcripts in different inflorescence organs and in leaf tissue suggests that some TCP transcripts of O. italica exert their role only in specific tissues, while others may play multiple roles in different tissues. In addition, the evolutionary analysis showed a general purifying selection acting on the coding region of these transcripts.

  17. Biological optimization of simultaneous boost on intra-prostatic lesions (DILs): sensitivity to TCP parameters.

    Science.gov (United States)

    Azzeroni, R; Maggio, A; Fiorino, C; Mangili, P; Cozzarini, C; De Cobelli, F; Di Muzio, N G; Calandrino, R

    2013-11-01

    The aim of this investigation was to explore the potential of biological optimization in the case of simultaneous integrated boost on intra-prostatic dominant lesions (DIL) and evaluating the impact of TCP parameters uncertainty. Different combination of TCP parameters (TD50 and γ50 in the Poisson-like model), were considered for DILs and the prostate outside DILs (CTV) for 7 intermediate/high-risk prostate patients. The aim was to maximize TCP while constraining NTCPs below 5% for all organs at risk. TCP values were highly depending on the parameters used and ranged between 38.4% and 99.9%; the optimized median physical doses were in the range 94-116 Gy and 69-77 Gy for DIL and CTV respectively. TCP values were correlated with the overlap PTV-rectum and the minimum distance between rectum and DIL. In conclusion, biological optimization for selective dose escalation is feasible and suggests prescribed dose around 90-120 Gy to the DILs. The obtained result is critically depending on the assumptions concerning the higher radioresistence in the DILs. In case of very resistant clonogens into the DIL, it may be difficult to maximize TCP to acceptable levels without violating NTCP constraints.

  18. Improve Performance of TCP New Reno Over Mobile Ad-Hoc Network Using ABRA

    Directory of Open Access Journals (Sweden)

    Dhananjay Bisen

    2011-05-01

    Full Text Available In a mobile ad hoc network, temporary link failures and route changes occur frequently. With theassumption that all packet losses are due to congestion, TCP performs poorly in such an environment.There are many versions of TCP which modified time to time as per need. In this paper modificationsintroduced on TCP New Reno over mobile ad-hoc networks using calculation of New RetransmissionTime out (RTO, to improve performance in term of congestion control. To calculate New RTO, adaptivebackoff response approach (ABRA in TCP New Reno was applied which suggest ABRA New Reno. Itutilizes an ABRA by which congestion window and slow start threshold values were decreased wheneveran acknowledgement is received and new backoff value calculate from smoothed round trip time.Evaluation based on comparative study of ABRA New Reno with other TCP Variants like New Reno andReno was done using realistic parameters like TCP Packet Received, Packet Drop, Packets Retransmitted,Throughput, and Packet Delivery Ratio calculated by varying attributes of Node Speed, Number of Nodesand Pause Time. Implementation and simulations were performed in QualNet 4.0 simulator.

  19. TCP: a tool for designing chimera proteins based on the tertiary structure information

    Directory of Open Access Journals (Sweden)

    Nishida Reina

    2009-01-01

    Full Text Available Abstract Background Chimera proteins are widely used for the analysis of the protein-protein interaction region. One of the major issues is the epitope analysis of the monoclonal antibody. In the analysis, a continuous portion of an antigen is sequentially substituted into a different sequence. This method works well for an antibody recognizing a linear epitope, but not for that recognizing a discontinuous epitope. Although the designing the chimera proteins based on the tertiary structure information is required in such situations, there is no appropriate tool so far. Results In light of the problem, we developed a tool named TCP (standing for a Tool for designing Chimera Proteins, which extracts some sets of mutually orthogonal cutting surfaces for designing chimera proteins using a genetic algorithm. TCP can also incorporate and consider the solvent accessible surface area information calculated by a DSSP program. The test results of our method indicate that the TCP is robust and applicable to various shapes of proteins. Conclusion We developed TCP, a tool for designing chimera proteins based on the tertiary structure information. TCP is robust and possesses several favourable features, and we believe it is a useful tool for designing chimera proteins. TCP is freely available as an additional file of this manuscript for academic and non-profit organization.

  20. Improve performance of tcp new reno over mobile ad-hoc network using abra

    CERN Document Server

    Bisen, Dhananjay

    2011-01-01

    In a mobile ad hoc network, temporary link failures and route changes occur frequently. With the assumption that all packet losses are due to congestion, TCP performs poorly in such an environment. There are many versions of TCP which modified time to time as per need. In this paper modifications introduced on TCP New Reno over mobile ad-hoc networks using calculation of New Retransmission Time out (RTO), to improve performance in term of congestion control. To calculate New RTO, adaptive backoff response approach (ABRA) in TCP New Reno was applied which suggest ABRA New Reno. It utilizes an ABRA by which congestion window and slow start threshold values were decreased whenever an acknowledgement is received and new backoff value calculate from smoothed round trip time. Evaluation based on comparative study of ABRA New Reno with other TCP Variants like New Reno and Reno was done using realistic parameters like TCP Packet Received, Packet Drop, Packets Retransmitted, Throughput, and Packet Delivery Ratio calcu...

  1. Analysis of Proactive and Reactive Manet Routing Protocols Under Selected TCP Variants

    Directory of Open Access Journals (Sweden)

    Iffat Syad

    2013-08-01

    Full Text Available A Mobile Ad hoc Network (MANET, with its inherent dynamic and flexible architecture, demonstrates attractive potential for military applications. It is able to overcome traditional communications limitations through its automatic relaying and self - healing/forming features. MANE T nodes perform the routing functions themselves. Due to the limited wireless transmission range, the routing generally consists of multiple hops. Therefore, the nodes depend on one another to forward packets to the destinations. In a Mobile Ad Hoc Network (MANET, temporary link failures and route changes happen frequently. With the assumption that all packet losses are due to congestion, Transport Control Protocol (TCP performs poorly in such an environment. One problem of TCP in such environments is its inability to distinguish losses induced by the lossy wireless channel from the ones due to network congestion. Many TCP variants have been developed for the improved performance of TCP in MANET. In this research, through simulations that were carried out by using Network Simulator-2 (NS-2 , the selected MANET Routing protocols i.e. DSR and DSDV were analyzed in accordance with their finest performance of packets delivery rate, average end - to - end delay, and packet dropping, under TCP Vegas and TCP Newreno with mobility consideration. The simulation results indicate that DSDV has a b etter throughput performance but higher average end-to-end delay and packet drop ratioas compared to DSR

  2. Performance of TCP Vegas, Bic and Reno Congestion Control Algorithms on Iridium Satellite Constellations

    Directory of Open Access Journals (Sweden)

    M.Nirmala

    2012-11-01

    Full Text Available Satellite networking is different from wired or wireless networks. The behavior and the performance of TCP/IP in normal wireless network as well as in wired network are different from one another. The TCP/IP protocol was not designed to perform well over high-latency or noisy channels so its performance over satellite networks are totally different. Each satellite networks/constellations have different properties. The deployment height, motion, direction, link capacity – all differ from one satellite constellations to another. So, certainly the behavior of TCP/IP will considerably differ from one satellite constellations than another.The Performance of three different TCP Congestion algorithms, Vegas, Reno and Bic are taken for evaluation on the simulated satellite network Iridium and the performance of the three algorithms under the satellites constellation is measured using suitable metrics. It is observed that, irrespective of the high end to end delay, the behavior of TCP/IP under Satellite network is somewhat resembling a high latency wired network. TCP under satellite network is not like that of a mobile ADHOC network. The observation resulted that the overall performance of Vegas was good in Iridium constellations. These reasons should be explored for designing a better congestion control algorithm exclusively for Satellite Networks.

  3. Experiences with TCP/IP over an ATM OC12 WAN

    Energy Technology Data Exchange (ETDEWEB)

    Nitzan, Rebecca L.; Tierney, Brian L.

    1999-12-23

    This paper discusses the performance testing experiences of a 622.08 Mbps OC12 link. The link will be used for large bulk data transfer, and as such, of interest are both the ATM level throughput rates and end-to-end TCP/IP throughput rates. Tests were done to evaluate the ATM switches, the IP routers, the end hosts, as well as the underlying ATM service provided by the carrier. A low level of cell loss, (resulting in <.01 % packet loss), decreased the TCP throughput rate considerably when one TCP flow was trying to use the entire OC12 bandwidth. Identifying and correcting cell loss in the network proved to be extremely difficult. TCP Selective Acknowledgement (SACK) improved performance dramatically, and the maximum throughput rate increased from 300 Mbps to 400 Mbps. The effects of TCP slow start on performance at OC12 rates are also examined, and found to be insignificant for very large file transfers (e.g., for a 10 GB file). Finally, a history of TCP performance over high-speed networks is presented.

  4. A Survey of DDOS Attacks in TCP/IP Stack

    Directory of Open Access Journals (Sweden)

    P.C. Senthil Mahesh

    2014-08-01

    Full Text Available The aim of study is to discuss DDOS attack in TCP/IP layer. A Denial-of-Service (DoS or Distributed Denial-of-Service (DDoS attack is an attempt to make a device or network source not available to its designed customers. The purposes and objectives of a DoS attack may differ, it usually includes initiatives to momentarily or consistently disrupt or hold solutions of a variety linked with the Online. As explanation, DDoS (Distributed Denial of Service attack are sent by two or more individuals, or bots. DoS (Denial of Service attack are sent by one person or system. DoS attack typically focus on sites or solutions organized on high-profile web or web servers such as financial institutions, bank card payment gateways and even main name servers. This technique has now seen comprehensive use in certain activities, used by server owners, or dissatisfied opponents on activities. Progressively, DoS attack have also been used as a way of level of resistance.

  5. Embedded TCP/IP Stack Implemetation on TMS320VC5402%在TMS320VC5402上实现的嵌入式TCP/IP协议栈

    Institute of Scientific and Technical Information of China (English)

    曲延滨; 冯立国; 苏健勇

    2004-01-01

    实现一个运行在16位数字信号处理器TMS320VC5402上的小型嵌入式TCP/IP协议栈.对TCP/IP协议中的IP协议、ARP协议、UDP协议进行分析,完成基于TCP/IP协议的嵌入式网络系统.

  6. Comparative histomorphometric analysis between α-Tcp cement and β-Tcp/Ha granules in the bone repair of rat calvaria

    Directory of Open Access Journals (Sweden)

    Gisela Grandi

    2011-03-01

    Full Text Available This study compared the effect of two bioceramics on the process of bone repair: α-tricalcium phosphate (α-TCP cement and β-tricalcium phosphate hydroxyapatite particles (β-TCP/HA. Calvarial defects were created in 50 rats, divided into two groups (α and β/HA. Software was used at 7, 21, 60, 90 and 120 days to assess bone formation. Mean new bone formation rates were as follows: α group, 1.6% at 7 days, 5.24% at 21 days, 24% at 60 days, 30.21% at 90 days and 50.59% at 120 days; β/HA group, 1.94% at 7 days, 2.53% at 21 days, 12.47% at 60 days, 26.84% at 90 days and 38.82% at 120 days; control group, 0.15% at 7 days, 10.12% at 21 days, 15.10% at 60 days, 18.94% at 90 days, 48.50% at 120 days. Both materials are osteoconductive and biocompatible. Perhaps the larger rate of new bone formation observed in the α-TCP group, it also occurs in the β-TCP/HA group within a longer time period.

  7. TCP/IP网络协议栈攻击防范措施研究分析%TCP / IP Protocol Stack Attack Prevention Measures Study

    Institute of Scientific and Technical Information of China (English)

    曾振东

    2013-01-01

    由于TCP/IP网络协议栈在设计上的安全缺陷和脆弱性,使得在协议栈各个网络层次上均存在着各种类型的网络攻击技术方法,对互联网及内部网络的安全性造成威胁.该文主要介绍对网络各层的安全协议,也分别列举说明了各层的网络安全防范措施,对如何改善网络安全配置和使用条件,对TCP/IP网络协议栈攻击的防范技术及其发展,进行研究分析.%As the TCP/IP protocol stack in the design of security flaws and vulnerabilities in the protocol stack, so that each net?work level there are various types of network attack technology, on the Internet and the internal network security threat. This pa?per mainly introduces the network layer security protocol, were also examples of each layer of network security precautions, on how to improve the network security configuration and use conditions, the TCP/IP protocol stack attack prevention technology and its development, research and analysis.

  8. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA) as a Candidate Subunit Cholera Vaccine

    Science.gov (United States)

    Molaee, Neda; Amozande-Nobaveh, Alireza; Soleyman, Mohammad Reza

    2017-01-01

    Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response. PMID:28191473

  9. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA as a Candidate Subunit Cholera Vaccine

    Directory of Open Access Journals (Sweden)

    Neda Molaee

    2017-01-01

    Full Text Available Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response.

  10. Evolution of the Immune Response against Recombinant Proteins (TcpA, TcpB, and FlaA) as a Candidate Subunit Cholera Vaccine.

    Science.gov (United States)

    Molaee, Neda; Mosayebi, Ghasem; Amozande-Nobaveh, Alireza; Soleyman, Mohammad Reza; Abtahi, Hamid

    2017-01-01

    Vibrio cholerae is the causative agent of cholera and annually leads to death of thousands of people around the globe. Two factors in the pathogenesis of this bacterium are its pili and flagella. The main subunits of pili TcpA, TcpB, and FlaA are the constituent subunit of flagella. In this study, we studied the ability of pili and flagella subunits to stimulate immune responses in mice. After amplification of TcpA, TcpB, and FlaA genes using PCR, they were cloned in expression plasmids. After production of the above-mentioned proteins by using IPTG, the proteins were purified and then approved using immunoblot method. After injection of the purified proteins to a mice model, immune response stimulation was evaluated by measuring the levels of IgG1 and IgG2a antibody titers, IL5 and IFN-γ. Immune response stimulation against pili and flagella antigens was adequate. Given the high levels of IL5 titer and IgG1 antibody, the stimulated immune response was toward Th1. Humoral immune response stimulation is of key importance in prevention of cholera. Our immunological analysis shows the appropriate immune response in mice model after vaccination with recombinant proteins. The high level of IL5 and low level of IFN-γ show the activation of Th2 cell response.

  11. Network Programming tcp/ip protocol and socket discussion%网络编程tcp/ip协议与socket论述

    Institute of Scientific and Technical Information of China (English)

    严谦; 阳泳

    2016-01-01

    随着互联网技术的不断发展,网络通信成为当前互联网技术的重要技术,所以当前网络编程技术成为当前互联网通信发展的核心技术。网络编程主要是的通过使用套接字来实现进程间的编程,在Windows系统中的网络编程的套接字winscok,而在linux系统中最常见的套接字就是socket,本文就linux网络编程中的tcp、ip协议以及socket套接字问题进行详细的论述。%With the continuous development of Internet technology, network communications become an important technology of Internet technology, so the current network programming technology as the core technology of the current development of Internet communications. Network programming primarily achieved through the use of socket programming between processes in Windows system network programming socket winscok, while in linux system is the most common socket socket, paper linux Network Programming the tcp, ip protocol and socket socket issues are discussed in detail.

  12. CNoA: Challenging Number Approach for uncovering TCP SYN flooding using SYN spoofing attack

    Directory of Open Access Journals (Sweden)

    L.Kavisankar

    2011-10-01

    Full Text Available The challenging number is used for the detection of Spoofing attack. The IP Spoofing is considered to beone of the potentially brutal attack which acts as a tool for the DDoS attack which is considered to be amajor threat among security problems in today’s internet. These kinds of attack are extremely severe.They bring down business of company drastically. DDoS attack can easily exhaust the computing andcommunication resources of its victim within a short period of time. There are attacks exploiting somevulnerability or implementation bug in the software implementation of a service to bring that down andsome attacks will use all the available resources at the target machine. This deals on attacks thatconsume all the bandwidth available to the victim machine. While concentrating on the bandwidth attackthe TCP SYN flood is the more prominent attack. TCP/IP protocol suite is the most widely used protocolsuite for data communication. The TCP SYN flood works by exhausting the TCP connection queue of thehost and thus denying legitimate connection request. There are various methods used to detect andprevent this attack, one of which is to block the packet based on SYN flag count from the same IP address.This kind of prevention methods becomes unsuitable when the attackers use the Spoofed IP address. TheSYN spoofing becomes a major tool the TCP SYN flooding. For the prevention of this kind of attacks, theTCP specific probing is used in the proposed scheme where the client is requested challenging numberwhile sending the ACK in the three way hand shake. This is very useful to find the Spoofed IPPackets/TCP SYN flood and preventing them.

  13. Combining phylogenetic and syntenic analyses for understanding the evolution of TCP ECE genes in eudicots.

    Science.gov (United States)

    Citerne, Hélène L; Le Guilloux, Martine; Sannier, Julie; Nadot, Sophie; Damerval, Catherine

    2013-01-01

    TCP ECE genes encode transcription factors which have received much attention for their repeated recruitment in the control of floral symmetry in core eudicots, and more recently in monocots. Major duplications of TCP ECE genes have been described in core eudicots, but the evolutionary history of this gene family is unknown in basal eudicots. Reconstructing the phylogeny of ECE genes in basal eudicots will help set a framework for understanding the functional evolution of these genes. TCP ECE genes were sequenced in all major lineages of basal eudicots and Gunnera which belongs to the sister clade to all other core eudicots. We show that in these lineages they have a complex evolutionary history with repeated duplications. We estimate the timing of the two major duplications already identified in the core eudicots within a timeframe before the divergence of Gunnera and after the divergence of Proteales. We also use a synteny-based approach to examine the extent to which the expansion of TCP ECE genes in diverse eudicot lineages may be due to genome-wide duplications. The three major core-eudicot specific clades share a number of collinear genes, and their common evolutionary history may have originated at the γ event. Genomic comparisons in Arabidopsis thaliana and Solanumlycopersicum highlight their separate polyploid origin, with syntenic fragments with and without TCP ECE genes showing differential gene loss and genomic rearrangements. Comparison between recently available genomes from two basal eudicots Aquilegiacoerulea and Nelumbonucifera suggests that the two TCP ECE paralogs in these species are also derived from large-scale duplications. TCP ECE loci from basal eudicots share many features with the three main core eudicot loci, and allow us to infer the makeup of the ancestral eudicot locus.

  14. Engineering vascularized bone grafts by integrating a biomimetic periosteum and β-TCP scaffold.

    Science.gov (United States)

    Kang, Yunqing; Ren, Liling; Yang, Yunzhi

    2014-06-25

    Treatment of large bone defects using synthetic scaffolds remain a challenge mainly due to insufficient vascularization. This study is to engineer a vascularized bone graft by integrating a vascularized biomimetic cell-sheet-engineered periosteum (CSEP) and a biodegradable macroporous beta-tricalcium phosphate (β-TCP) scaffold. We first cultured human mesenchymal stem cells (hMSCs) to form cell sheet and human umbilical vascular endothelial cells (HUVECs) were then seeded on the undifferentiated hMSCs sheet to form vascularized cell sheet for mimicking the fibrous layer of native periosteum. A mineralized hMSCs sheet was cultured to mimic the cambium layer of native periosteum. This mineralized hMSCs sheet was first wrapped onto a cylindrical β-TCP scaffold followed by wrapping the vascularized HUVEC/hMSC sheet, thus generating a biomimetic CSEP on the β-TCP scaffold. A nonperiosteum structural cell sheets-covered β-TCP and plain β-TCP were used as controls. In vitro studies indicate that the undifferentiated hMSCs sheet facilitated HUVECs to form rich capillary-like networks. In vivo studies indicate that the biomimetic CSEP enhanced angiogenesis and functional anastomosis between the in vitro preformed human capillary networks and the mouse host vasculature. MicroCT analysis and osteocalcin staining show that the biomimetic CSEP/β-TCP graft formed more bone matrix compared to the other groups. These results suggest that the CSEP that mimics the cellular components and spatial configuration of periosteum plays a critical role in vascularization and osteogenesis. Our studies suggest that a biomimetic periosteum-covered β-TCP graft is a promising approach for bone regeneration.

  15. β-TCP granules mixed with reticulated hyaluronic acid induce an increase in bone apposition.

    Science.gov (United States)

    Aguado, Eric; Pascaretti-Grizon, Florence; Gaudin-Audrain, Christine; Goyenvalle, Eric; Chappard, Daniel

    2014-02-01

    β beta-tricalcium phosphate (β-TCP) granules are suitable for repair of bone defects. They have an osteoconductive effect shortly after implantation. However, dry granules are difficult to handle in the surgical room because of low weight and lack of cohesion. Incorporation of granules in a hydrogel could be a satisfactory solution. We have investigated the use of hyaluronic acid (HyA) as an aqueous binder of the granules. β-TCP granules were prepared by the polyurethane foam technology. Commercially available linear (LHya) and reticulated hyaluronic acid (RHyA) in aqueous solution were used to prepare a pasty mixture that can be handled more easily than granules alone. Thirteen New Zealand White rabbits (3.5-3.75 kg) were used; a 4 mm hole was drilled in each femoral condyle. After flushing, holes were filled with either LHyA, RHyA, dry β-TCP granules alone, β-TCP granules + LHyA and β-TCP granules + RHyA. Rabbits were allowed to heal for one month, sacrificed and femurs were harvested and analysed by microCT and histomorphometry. The net amount of newly formed bone was derived from measurements done after thresholding the microCT images for the material and for the material+bone. LHyA and RHyA did not result in healing of the grafted area. LHyA was rapidly eluted from the grafted zone but allowed deposition of more granules, although the amount of formed bone was not significantly higher than with β-TCP granules alone. RHyA permitted the deposition of more granules which induced significantly more bone trabeculae without inducing an inflammatory reaction. RHyA appears to be a good vehicle to implant granules of β-TCP, since HyA does not interfere with bone remodeling.

  16. Genome-wide identification and expression analysis of the ClTCP transcription factors in Citrullus lanatus.

    Science.gov (United States)

    Shi, Pibiao; Guy, Kateta Malangisha; Wu, Weifang; Fang, Bingsheng; Yang, Jinghua; Zhang, Mingfang; Hu, Zhongyuan

    2016-04-12

    The plant-specific TCP transcription factor family, which is involved in the regulation of cell growth and proliferation, performs diverse functions in multiple aspects of plant growth and development. However, no comprehensive analysis of the TCP family in watermelon (Citrullus lanatus) has been undertaken previously. A total of 27 watermelon TCP encoding genes distributed on nine chromosomes were identified. Phylogenetic analysis clustered the genes into 11 distinct subgroups. Furthermore, phylogenetic and structural analyses distinguished two homology classes within the ClTCP family, designated Class I and Class II. The Class II genes were differentiated into two subclasses, the CIN subclass and the CYC/TB1 subclass. The expression patterns of all members were determined by semi-quantitative PCR. The functions of two ClTCP genes, ClTCP14a and ClTCP15, in regulating plant height were confirmed by ectopic expression in Arabidopsis wild-type and ortholog mutants. This study represents the first genome-wide analysis of the watermelon TCP gene family, which provides valuable information for understanding the classification and functions of the TCP genes in watermelon.

  17. Evaluation of TcpF-A2-CTB chimera and evidence of additive protective efficacy of immunizing with TcpF and CTB in the suckling mouse model of cholera.

    Directory of Open Access Journals (Sweden)

    Gregory A Price

    Full Text Available The secreted colonization factor, TcpF, which is produced by Vibrio cholerae 01 and 0139, has generated interest as a potential protective antigen in the development of a subunit vaccine against cholera. This study evaluated immunogenicity/protective efficacy of a TcpF holotoxin-like chimera (TcpF-A2-CTB following intraperitoneal immunization compared to TcpF alone, a TcpF+CTB mixture, or CTB alone. Immunization with the TcpF-A2-CTB chimera elicited significantly greater amounts of anti-TcpF IgG than immunization with the other antigens (P<0.05. Protective efficacy was measured using 6-day-old pups reared from immunized dams and orogastrically challenged with a lethal dose of El Tor V. cholerae 01 Inaba strain N16961. Protection from death, and weight loss analysis at 24 and 48 hours post-infection demonstrated that immunization with TcpF alone was poorly protective. However, immunization with TcpF+CTB was highly protective and showed a trend toward greater protection than immunization with CTB alone (82% vs 64% survival. Immunization with the TcpF-A2-CTB chimera demonstrated less protection (50% survival than immunization with the TcpF+CTB mixture. The TcpF-A2-CTB chimera used for this study contained the heterologous classical CTB variant whereas the El Tor CTB variant (expressed by the challenge strain was used in the other immunization groups. For all immunization groups that received CTB, quantitative ELISA data demonstrated that the amounts of serum IgG directed against the homologous immunizing CTB antigen was statistically greater than the amount to the heterologous CTB antigen (P≤0.003. This finding provides a likely explanation for the poorer protection observed following immunization with the TcpF-A2-CTB chimera and the relatively high level of protection seen after immunization with homologous CTB alone. Though immunization with TcpF alone provided no protection, the additive protective effect when TcpF was combined with CTB

  18. Endothelial cell cultured on HA/TCP/chitosan scaffold for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Bachtiar EW

    2011-06-01

    Full Text Available Background: Angiogenesis is crucial for the success of bone reconstruction through tissue engineering. Currently, is still not known the activity of endothelial cells that is responsible for blood vessel formation, cultured in HA/TCP/chitosan scaffold. The ability of the scaffold to facilitate the proliferation and migration of endothelial cell to form blood vessel is essential for cell survival especially in the inner area of the scaffold that is susceptible for cell death if adequate vascularization is not occurred. Purpose: The purpose of this study was to evaluate the porosity of HA/TCP/chitosan scaffold and the biocompatibility of HA/TCP/chitosan scaffold to endothelial cells. Methods: Endothelial cells were isolated from umbilical vein (human umbilical vein endothelial cells/ HUVEC. HA/ TCP/chitosan scaffold was made from two gelling agents and various basic washing solutions. The characteristic of scaffold was examined by scanning electron microscopy. The activity of HUVEC was evaluated by MTT assay. Results: Initial average scaffold porosity size range from 68 μm and increased up to 134 μm after 7 days incubation with 10 mg/L lysozyme. There was no significant difference in the viability of HUVEC incubated with the scaffold compared to control. Conclusion: HA/TCP/chitosan has a good biocompatibility for HUVEC. This condition supports the activity of HUVEC in the scaffold for angiogenesis process, to provide oxygen and nutrient necessary for osteoblast.Latar belakang: Angiogenesis merupakan proses yang penting untuk keberhasilan rekonstruksi tulang melalui rekayasa jaringan. Saat ini, aktifitas sel endotel pembentuk dinding pembuluh darah pada HA/TCP/chitosan scaffold belum diketahui. Kemampuan scaffold sebagai tempat proliferasi dan migrasi sel endotel untuk membentuk pembuluh darah penting untuk kelangsungan hidup sel osteoblast terutama di bagian dalam scaffold. Tujuan: Mengevaluasi porositas HA/TCP/chitosan scaffold serta sifat

  19. Performance Analysis of TCP and SCTP For Congestion Losses In Manet

    Directory of Open Access Journals (Sweden)

    Er.Amritpal Kaur

    2015-06-01

    Full Text Available Transmission control protocols have been used for data transmission process. TCP has been pre-owned for data transmission over wired communication having different bandwidths and message delays over the network. TCP provides communication using 3-handshake which sends RTS and ACK comes from server end and data message has been transmitted over the bandwidth provided. This does not provide security over flooding attack occurred on the network. TCP provides communication between different nodes of the wired communication but when multi-streaming occurs in a network TCP does not provides proper throughput of the system which is major problem that occurred in the previous system. In the proposed work, to overcome this problem SCTP transmission control protocol has been implemented for the system performance of the system. SCTP provides 4-handshake communication in the message transmit due to which security factor get increases and this also provides communication services over multi-streaming and multi-homing. Multiple sender and receivers can communicate over wired network using various approaches of communication through same routers, which degrades in the TCP protocol. In final we evaluate parameters for performance evaluation. Here, we designed and implemented our test bed using Network Simulator (NS-2.35 to test the performance of both Routing protocols.

  20. Fabrication of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering.

    Science.gov (United States)

    Lou, Tao; Wang, Xuejun; Song, Guojun; Gu, Zheng; Yang, Zhen

    2014-08-01

    Polymer and ceramic composite scaffolds play a crucial role in bone tissue engineering. In an attempt to mimic the architecture of natural extracellular matrix (ECM), poly(l-lactic acid)/β-tricalcium phosphate (PLLA/β-TCP) nanocomposite scaffolds with a hierarchical pore structure were fabricated by combining thermal induced phase separation and salt leaching techniques. The nanocomposite scaffold consisted of a nanofibrous PLLA matrix with a highly interconnected, high porosity (>93%) hierarchical pore structure with pore diameters ranging from 500nm to 300μm and a homogeneously distributed β-TCP nanoparticle phase. The nanofibrous PLLA matrix had a fiber diameter of 70-300nm. The nanocomposite scaffolds possess three levels of hierarchical structure: (1) porosity; (2) nanofibrous PLLA struts comprising the pore walls; and (3) β-TCP nanoparticle phase. The β-TCP nanoparticle phase improved the mechanical properties and bioactivity of the PLLA matrix. The nanocomposite scaffolds supported MG-63 osteoblast proliferation, penetration, and ECM deposition, indicating the potential of PLLA/β-TCP nanocomposite scaffolds with hierarchical porosity for bone tissue engineering applications.

  1. Experimental Evaluation of Memory Effects on TCP Traffic in Congested Networks

    Directory of Open Access Journals (Sweden)

    Kulvinder Singh

    2010-09-01

    Full Text Available Today the Internet is a worldwide-interconnected computer network that transmits data by packet switching based on the TCP/IP protocol suite. Internet has TCP as the main protocol of the transport layer. The performance of TCP is studied by many researchers. They are trying to analytically characterizing the throughput of TCP's congestion control mechanism. Internet routers were widely believed to need big memory spaces. Commercial routers today have huge packet memory spaces, often storing millions of packets, under the assumption that big memory spaces lead to good statistical multiplexing and hence efficient use of expensive long-haul links. In this paper, we summarize the works and present the experimental study result with big memory space size and give a qualitative analysis of the result. Our conclusion is that the, round-trip time (RTT is not increased by linear, but by quadric when the memory space size of the bottleneck is big enough. Our goal is to estimate the average queue length of the memory space size and develop a TCP model based on RTT and the average queue length.

  2. Modiifcation ofb-TCP/PLGA Scaffold and Its Effect on Bone Regeneration in vivo

    Institute of Scientific and Technical Information of China (English)

    LIN Liulan; GAO Haitao

    2016-01-01

    In order to look for the best proportion ofβ-tricalcium phosphate(β-TCP) and poly(lactide-co-glycolide) (PLGA) we fabricated porous compositesβ-TCP/PLGA scaffold using freeze-drying method. Morphological characterization using scanning electron microscopy showed that the interconnected pore distribution was even and there was no signiifcant difference with the increase of PLGA content. Moreover, the porosity, compressive strength and degradation in vitro were characterized. The fabricated scaffolds with increased PLGA in the compositesβ-TCP/PLGA scaffolds will get stronger mechanical property and better appearance, furthermore, get suitable environment for cells. According to the evaluation indexes for the tissue engineering scaffold, the group of scaffold (β-TCP/PLGA=6:4) was selected to evaluate the induced cell adhesion and proliferative ability of the scaffolds. Then as transplant embed into the bone critical defect sites on rats femur. The repairing processes of bone defect sites were characterized by X-ray analysis within 12 weeks. X-ray analysis showed that the bone defect sites all displayed the formation of callus obviously, In summary, our data suggest that the scaffold (β-TCP/PLGA=6:4) has a promising clinical future in regeneration of bone critical defects .

  3. LWD–TCP complex activates the morning gene CCA1 in Arabidopsis

    Science.gov (United States)

    Wu, Jing-Fen; Tsai, Huang-Lung; Joanito, Ignasius; Wu, Yi-Chen; Chang, Chin-Wen; Li, Yi-Hang; Wang, Ying; Hong, Jong Chan; Chu, Jhih-Wei; Hsu, Chao-Ping; Wu, Shu-Hsing

    2016-01-01

    A double-negative feedback loop formed by the morning genes CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) and the evening gene TIMING OF CAB EXPRESSION1 (TOC1) contributes to regulation of the circadian clock in Arabidopsis. A 24-h circadian cycle starts with the peak expression of CCA1 at dawn. Although CCA1 is targeted by multiple transcriptional repressors, including PSEUDO-RESPONSE REGULATOR9 (PRR9), PRR7, PRR5 and CCA1 HIKING EXPEDITION (CHE), activators of CCA1 remain elusive. Here we use mathematical modelling to infer a co-activator role for LIGHT-REGULATED WD1 (LWD1) in CCA1 expression. We show that the TEOSINTE BRANCHED 1-CYCLOIDEA-PCF20 (TCP20) and TCP22 proteins act as LWD-interacting transcriptional activators. The concomitant binding of LWD1 and TCP20/TCP22 to the TCP-binding site in the CCA1 promoter activates CCA1. Our study reveals activators of the morning gene CCA1 and provides an action mechanism that ensures elevated expression of CCA1 at dawn to sustain a robust clock. PMID:27734958

  4. A More Complete Model for TCP Connections Established between One Server and Many Receivers

    Institute of Scientific and Technical Information of China (English)

    LINYu; CHENGShiduan; WUHaitao; WANGChonggang

    2003-01-01

    Different from previous TCP (transmis-sion control program) modeling works, this paper presents a more complete analytical model of multiple TCP con-nections established between a busy server and multiple receivers under two distinct cases: the case there is suffi-cient bandwidth and the case there is a bandwidth bottle-neck link between the server and receivers. In the former case, the server will become the bottleneck of the whole system, and TCP behaviors are different from the model presented before. However, in the latter case, multiple TCP connections will share the bandwidth of the bottle-neck link. Based on the analysis of working flows in the system and a M/G/1 queueing model, the RTT and long-term TCP throughput formulae are derived in terms of number of TCPs, packet loss rate, and end-to-end delay.And the effect of maximum window size is also investi-gated. The simulation results confirm that new model is more accurate than previous model.

  5. Edge isolation of transparent conductive polymer (TCP) thin films on flexible substrates using UV laser ablation.

    Science.gov (United States)

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei

    2012-06-01

    The purpose of this study was to directly use the writing techniques for the complex electrode edge isolation of transparent conductive polymer (TCP) thin films by a nanosecond pulsed UV laser processing system. The processing parameters including the laser pulse energy, the pulse repetition frequency, and the scan speed of galvanometers were examined to ablate the TCP films deposited on polyethylene terephtalate substrates of 188 microm thick. The thickness of TCP films was approximately 20 nm. The laser pulse repetition frequency and the scan speed of galvanometers were applied to calculate the overlapping rate of laser spots and to discuss the patterning region quality. Surface morphology, edge quality, and width and depth of edge isolated patterning structures after laser ablation process were measured by a three-dimensional confocal laser scanning microscope. In addition, the electrical conductivity of ablated TCP films was measured by a four-point probes instrument. After isolated line patterning was formed, the ablated TCP films with a better edge quality were obtained directly when the overlapping rate of laser spots, the scan speed, and the pulse repetition rate were 83.3%, 200 mm/s, and 40 kHz, respectively. The better surface morphology of electrode pattern structures was also obtained when the scan speed and the pulse repetition rate were 500 mm/s and 40 kHz, respectively.

  6. Experimental and Theoretical Analysis of Storage Friendly TCP Performance in Distributed Storage Area Network

    Directory of Open Access Journals (Sweden)

    Suresh Muknahallipatna

    2007-08-01

    Full Text Available Fibre channel storage area networks (SAN are widely implemented in production data center environments. Recently the storage industry has moved towards deployment of distributed SANs (DSAN, geographically dispersed across large physical distances. In a DSAN, specialized gateway devices interconnect the individual Fibre Channel (FC fabrics over IP networks using TCP/IP based protocols (iFCP or FCIP or over metro to long distance optical networks such as Dense Wavelength Division Multiplexing (DWDM based networks that utilize native FC ports supporting large numbers of link credits. When using TCP/IP based storage networking protocols to interconnect local FC fabrics in a DSAN, the sustained throughput achievable depends upon the link characteristics and TCP/IP stack implementation. Sustaining maximum possible storage traffic throughput across the wide area network enables practical DSAN deployments by maintaining the required site to site service level agreements.This study explores the effects of several TCP/IP modifications on sustained traffic throughput for a DSAN interconnected via iFCP gateways across an impaired network. The TCP/IP stack modifications, known as storage friendly, include changes to the window scaling, congestion avoidance, and fast recovery algorithms. The theoretical background and experimental results are presented to explain and illustrate these modifications.

  7. Ornithine In Vivo Administration Disrupts Redox Homeostasis and Decreases Synaptic Na(+), K (+)-ATPase Activity in Cerebellum of Adolescent Rats: Implications for the Pathogenesis of Hyperornithinemia-Hyperammonemia-Homocitrullinuria (HHH) Syndrome.

    Science.gov (United States)

    Zanatta, Ângela; Viegas, Carolina Maso; Hickmann, Fernanda Hermes; de Oliveira Monteiro, Wagner; Sitta, Angela; de Moura Coelho, Daniela; Vargas, Carmen Regla; Leipnitz, Guilhian; Wajner, Moacir

    2015-08-01

    Hyperornithinemia-hyperammonemia-homocitrullinuria (HHH) syndrome is an inborn error of metabolism caused by a defect in the transport of ornithine (Orn) into mitochondrial matrix leading to accumulation of Orn, homocitrulline (Hcit), and ammonia. Affected patients present a variable clinical symptomatology, frequently associated with cerebellar symptoms whose pathogenesis is poorly known. Although in vitro studies reported induction of oxidative stress by the metabolites accumulating in HHH syndrome, so far no report evaluated the in vivo effects of these compounds on redox homeostasis in cerebellum. Therefore, the present work was carried out to investigate the in vivo effects of intracerebellar administration of Orn and Hcit on antioxidant defenses (reduced glutathione concentrations and the activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, and glucose-6-phosphate dehydrogenase), lipid oxidation (malondialdehyde concentrations), as well as on the activity of synaptic Na(+), K(+)-ATPase, an enzyme highly vulnerable to free radical attack, in the cerebellum of adolescent rats. Orn significantly increased malondialdehyde levels and the activities of all antioxidant enzymes, and reduced Na(+), K(+)-ATPase activity. In contrast, glutathione concentrations were not changed by Orn treatment. Furthermore, intracerebellar administration of Hcit was not able to alter any of these parameters. The present data show for the first time that Orn provokes in vivo lipid oxidative damage, activation of the enzymatic antioxidant defense system, and reduction of the activity of a crucial enzyme involved in neurotransmission. It is presumed that these pathomechanisms may contribute at least partly to explain the neuropathology of cerebellum abnormalities and the ataxia observed in patients with HHH syndrome.

  8. Identification of two combined genes responsible for dechlorination of 3,5,6-trichloro-2-pyridinol (TCP) in Cupriavidus pauculus P2.

    Science.gov (United States)

    Cao, Li; Xu, Jianhong; Wu, Guang; Li, Mingxing; Jiang, Jiandong; He, Jian; Li, Shunpeng; Hong, Qing

    2013-09-15

    Dehalogenation is an important mechanism for degrading and detoxifying halogenated aromatics in microbes. However, the biochemical and molecular mechanisms of dehalogenation of 3,5,6-trichloro-2-pyridinol (TCP) are still unknown. In this study, a novel 6012 bp gene cluster was cloned from TCP-degrading strain P2, which was responsible for the dehalogenation of TCP. The cluster included a monooxygenase gene (tcpA1), a flavin reductase gene (tcpB1), tcpR1, orf1 and orf2. TcpA1 and TcpB1 were indispensable for the dehalogenation of TCP. They worked together to catalyze the dehalogenation of three chlorine of TCP, and generated a more readily biodegradable product of 3,6-dihydroxypyridine-2,5-dione. TcpA1 displayed the highest activity against TCP at 40°C and at pH 8.0. Cu(2+), Zn(2+), and Hg(2+) significantly inhibited enzyme activity. To the best of our knowledge, this is the first report on a gene cluster responsible for TCP degradation.

  9. Research and implementation of TCP/IP stack suitable for thin embedded server%嵌入式瘦服务器中TCP/IP协议栈的研究与实现

    Institute of Scientific and Technical Information of China (English)

    阙建荣; 卿立军

    2004-01-01

    文章分析和研究了嵌入式Intenet技术中应用于嵌入式瘦服务器的TCP/IP协议栈的特点.在此基础上设计并实现了一种适合于嵌入式瘦服务器的TCP/IP协议栈-emIP.

  10. A GA-based PID active queue management control design for TCP/IP networks

    Science.gov (United States)

    Kuo, H.-H.; Chen, C.-K.; Yan, J.-J.; Liao, T.-L.

    2008-02-01

    In this paper, a genetic algorithm-based (GA-based) proportional-integral-derivative (PID) controller as an active queue manager for Internet routers is proposed to reduce packet loss and improve network utilization in TCP/IP networks. Based on the window-based nonlinear dynamics, the TCP network was modeled as a time-delayed system with a saturated input due to the limitations of packet-dropping probability and the effects of propagation delays in TCP networks. An improved genetic algorithm is employed to derive optimal or near optimal PID control gains such that a performance index of integrated-absolute error (IAE) in terms of the error between the router queue length and the desired queue length is minimized. The performance of the proposed control scheme was evaluated in various network scenarios via a series of numerical simulations. The simulation results confirm that the proposed scheme outperforms other AQM schemes.

  11. Achieving Fair Throughput among TCP Flows in Multi-Hop Wireless Mesh Networks

    Science.gov (United States)

    Hou, Ting-Chao; Hsu, Chih-Wei

    Previous research shows that the IEEE 802.11 DCF channel contention mechanism is not capable of providing throughput fairness among nodes in different locations of the wireless mesh network. The node nearest the gateway will always strive for the chance to transmit data, causing fewer transmission opportunities for the nodes farther from the gateway, resulting in starvation. Prior studies modify the DCF mechanism to address the fairness problem. This paper focuses on the fairness study when TCP flows are carried over wireless mesh networks. By not modifying lower layer protocols, the current work identifies TCP parameters that impact throughput fairness and proposes adjusting those parameters to reduce frame collisions and improve throughput fairness. With the aid of mathematical formulation and ns2 simulations, this study finds that frame transmission from each node can be effectively controlled by properly controlling the delayed ACK timer and using a suitable advertised window. The proposed method reduces frame collisions and greatly improves TCP throughput fairness.

  12. Rapid restoration of methanogenesis in an acidified UASB reactor treating 2,4,6-trichlorophenol (TCP).

    Science.gov (United States)

    Díaz-Báez, María Consuelo; Valderrama-Rincon, Juan Daniel

    2017-02-15

    Anaerobic bioreactors are often used for removal of xenobiotic and highly toxic pollutants from wastewater. Most of the time, the pollutant is so toxic that the stability of the reactor becomes compromised. It is well known that methanogens are one of the most sensitive organisms in the anaerobic consortia and hence the stability of the reactors is highly dependant on methanogenesis. Unfortunately few studies have focused on recovering the methanogenic activity once it has been inhibited by highly toxic pollutants. Here we establish a quick recovery strategy for neutralization of an acidified UASB reactor after failure by intoxication with an excess of TCP in the influent. Once the reactor returned to pH values compatible with methanogenesis, biogas production was re-started after one day and the system was re-acclimated to TCP. Successful removal of TCP from synthetic wastewater was shown for concentrations up to 70mg/L after restoration.

  13. TCP-based window-size delegation method for TXOP Exchange in wireless local area networks

    Directory of Open Access Journals (Sweden)

    Hasegawa Go

    2011-01-01

    Full Text Available Abstract We propose a TCP window-size delegation method for downlink TXOP (transmission opportunity Exchange in wireless local area networks (WLANs. In our method, the 'compliant' stations (STAs cooperatively use their available bandwidth in accordance with their throughput demand. We realize our method only with minimal modifications of the TCP functions of a proxy server, which lets one station (the TXOP provider delegate TCP window size to another station (the TXOP client so that the provider delegates its TXOPs in WLANs to the client. Our method enables an STA to flexibly delegate TXOPs to another STA without adversely affecting the legacy STAs, which is confirmed by computer simulations. We also confirmed that our method requires no modification to legacy access points and STAs.

  14. Robust control tools for traffic monitoring in TCP/AQM networks

    CERN Document Server

    Ariba, Yassine; Rahme, Sandy; Labit, Yann

    2009-01-01

    Several studies have considered control theory tools for traffic control in communication networks, as for example the congestion control issue in IP (Internet Protocol) routers. In this paper, we propose to design a linear observer for time-delay systems to address the traffic monitoring issue in TCP/AQM (Transmission Control Protocol/Active Queue Management) networks. Due to several propagation delays and the queueing delay, the set TCP/AQM is modeled as a multiple delayed system of a particular form. Hence, appropriate robust control tools as quadratic separation are adopted to construct a delay dependent observer for TCP flows estimation. Note that, the developed mechanism enables also the anomaly detection issue for a class of DoS (Denial of Service) attacks. At last, simulations via the network simulator NS-2 and an emulation experiment validate the proposed methodology.

  15. An Advance Approach to Evaluate the Performance of the TCP Networks

    Directory of Open Access Journals (Sweden)

    Ibrahiem M.M. El Emary

    2005-01-01

    Full Text Available In this study, we present a new approach for estimating the performance of the TCP network depending on a mathematical formula which converts the conceptual performance parameter to a valuable one. With respect to TCP network performance, we consider the Random Early Detection (RED and RED-Based algorithms where both RED and RED-Based follow the Active Queue Management (AQM approach in TCP networks. Mainly, we make a comprehensive understanding of various network parameters that continually affect the network performance. The main parameters that are used given by: network throughput, link utilization, network average delay, and packet loss rate. Also in this study, we estimate a new parameter reflecting the network performance called Network Quality Parameter (NQP.

  16. Cascade Probability Control to Mitigate Bufferbloat under Multiple Real-World TCP Stacks

    Directory of Open Access Journals (Sweden)

    Hoang-Linh To

    2015-01-01

    Full Text Available Persistently full buffer problem, commonly known as bufferbloat, causes unnecessary additional latency and throughput degradation whenever congestion happens in Internet. Several proposed queue management schemes, with the debloat mission, are almost based on the modification of one-loop feedback control where the instability and bad transient behavior are still big challenges. In this paper, we present a cascade probability control scheme using margin optimal method to address such challenges under different kinds of real-world TCP stacks. Simulation results guarantee the measured round trip time tracking to a low value of delay (e.g., ≈180 ms under TCP Reno, and ≈130 ms under TCP Cubic and ≈50% delay reduction in comparison to current deployed queue management schemes in network devices.

  17. Study on β-TCP Coated Porous Mg as a Bone Tissue Engineering Scaffold Material

    Institute of Scientific and Technical Information of China (English)

    Fang Geng; Lili Tan; Bingchun Zhang; Chunfu Wu; Yonglian He; Jingyu Yang; Ke Yang

    2009-01-01

    Three-dimensional honeycomb-structured magnesium (Mg) scaffolds with interconnected pores of accurately controlled pore size and porosity were fabricated by laser perforation technique. Biodegradable and bioactive β-tricalcium phosphate (β-TCP) coatings were prepared on the porous Mg to further improve its biocompatibility, and the biodegradation mechanism was simply evaluated in vitro. It was found that the mechanical properties of this type of porous Mg significantly depended on its porosity. Elastic modulus and compressive strength similar to human bones could be obtained for the porous Mg with porosity of 42.6%-51%. It was observed that the human osteosarcoma cells (UMR106) were well adhered and proliferated on the surface of the β-TCP coated porous Mg, which indicates that the β-TCP coated porous Mg is promising to be a bone tissue engineering scaffold material.

  18. Investigation on TCP/IP Congestion Control in Optical Burst Switched (OBS Network

    Directory of Open Access Journals (Sweden)

    Ms. Payal Daryani

    2012-03-01

    Full Text Available Transport Control Protocol (TCP is the dominant protocol in modern communication networks, in which the issues of reliability, flow, and congestion control must be handled efficiently. In this review paper an analytical switching is used to exploit the huge bandwidth of optical fibers for future high speed internet backbone. It carries multiple packets, in their turn. Different aggregation schemes have been considered and evaluated.TCP performance greatly depends on the TCP congestion window behavior that is related to loss events occurring in the optical burst switched network, there is a special term called traffic shaping by which we control over the network according to the network load .that means we increase or decrease the send rate according to the network demand.

  19. Improved virtual queuing and dynamic EPD techniques for TCP over ATM

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Y.; Siu, K.Y.; Ren, W.

    1998-11-01

    It is known that TCP throughput can degrade significantly over UBR service in a congested ATM network, and the early packet discard (EPD) technique has been proposed to improve the performance. However, recent studies show that EPD cannot ensure fairness among competing VCs in a congested network, but the degree of fairness can be improved using various forms of fair buffer allocation techniques. The authors propose an improved scheme that utilizes only a single shared FIFO queue for all VCs and admits simple implementation for high speed ATM networks. The scheme achieves nearly perfect fairness and throughput among multiple TCP connections, comparable to the expensive per-VC queuing technique. Analytical and simulation results are presented to show the validity of this new scheme and significant improvement in performance as compared with existing fair buffer allocation techniques for TCP over ATM.

  20. Proactive TCP mechanism to improve Handover performance in Mobile Satellite and Terrestrial Networks

    CERN Document Server

    Vinayakray-Jani, Preetida

    2012-01-01

    Emerging standardization of Geo Mobile Radio (GMR-1) for satellite system is having strong resemblance to terrestrial GSM (Global System for Mobile communications) at the upper protocol layers and TCP (Transmission Control Protocol) is one of them. This space segment technology as well as terrestrial technology, is characterized by periodic variations in communication properties and coverage causing the termination of ongoing call as connections of Mobile Nodes (MN) alter stochastically. Although provisions are made to provide efficient communication infrastructure this hybrid space and terrestrial networks must ensure the end-to-end network performance so that MN can move seamlessly among these networks. However from connectivity point of view current TCP performance has not been engineered for mobility events in multi-radio MN. Traditionally, TCP has applied a set of congestion control algorithms (slow-start, congestion avoidance, fast retransmit, fast recovery) to probe the currently available bandwidth on...

  1. Determination of physical properties for β-TCP + chitosan biomaterial obtained on metallic 316L substrates

    Energy Technology Data Exchange (ETDEWEB)

    Mina, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Tecno-Academia ASTIN SENA Reginal Valle (Colombia); Castaño, A. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, J.C., E-mail: julio.cesar.caicedo@correo.univalle.edu.co [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia); Caicedo, H.H. [Biologics Research, Biotechnology Center of Excellence, Janssen R& D, LLC, Pharmaceutical Companies of Johnson & Johnson, Spring House, PA 19477 (United States); National Biotechnology & Pharmaceutical Association, Chicago, IL 60606 (United States); Aguilar, Y. [Tribology, Powder Metallurgy and Processing of Solid Recycled Research Group, Universidad del Valle, Cali (Colombia)

    2015-06-15

    Material surface modification, particularly the deposition of special coatings on the surface of surgical implants, is extensively used in bone tissue engineering applications. β-Tricalcium phosphate/Chitosan (β-TCP/Ch) coatings were deposited on 316L stainless steel (316L SS) substrates by a cathodic electro-deposition technique at different coating compositions. The crystal lattice arrangements were analyzed by X-Ray diffraction (XRD), and the results indicated that the crystallographic structure of β-TCP was affected by the inclusion of the chitosan content. The changes in the surface morphology as a function of increasing chitosan in the coatings via scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed that root-mean square values of the β-TCP/Ch coatings decreased by further increasing chitosan percentage. The elastic–plastic characteristics of the coatings were determined by conducting nanoindentation test, indicating that increase of chitosan percentage is directly related to increase of hardness and elastic modulus of the β-TCP/Ch coatings. Tribological characterization was performed by scratch test and pin-on-disk test to analyze the changes in the surface wear of β-TCP/Ch coatings. Finally, the results indicated an improvement in the mechanical and tribological properties of the β-TCP/Ch coatings as a function of increasing of the chitosan percentage. This new class of coatings, comprising the bioactive components, is expected not only to enhance the bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. - Highlights: • Superficial phenomenon that occurs in tribological surface of β-tricalcium phosphate-chitosan coatings. • Improvement on surface mechanical properties of ceramic-polymeric and response to surface tribological damage. • β-tricalcium phosphate-chitosan coatings that offer highest performance in the biomedical devices.

  2. Incorporation of RANKL promotes osteoclast formation and osteoclast activity on β-TCP ceramics.

    Science.gov (United States)

    Choy, John; Albers, Christoph E; Siebenrock, Klaus A; Dolder, Silvia; Hofstetter, Wilhelm; Klenke, Frank M

    2014-12-01

    β-Tricalcium phosphate (β-TCP) ceramics are approved for the repair of osseous defects. In large defects, however, the substitution of the material by authentic bone is inadequate to provide sufficient long-term mechanical stability. We aimed to develop composites of β-TCP ceramics and receptor activator of nuclear factor κ-B ligand (RANKL) to enhance the formation of osteoclasts and promote cell mediated calcium phosphate resorption. RANKL was adsorbed superficially onto β-TCP ceramics or incorporated into a crystalline layer of calcium phosphate by the use of a co-precipitation technique. Murine osteoclast precursors were seeded onto the ceramics. After 15 days, the formation of osteoclasts was quantified cytologically and colorimetrically with tartrate-resistant acidic phosphatase (TRAP) staining and TRAP activity measurements, respectively. Additionally, the expression of transcripts encoding the osteoclast gene products cathepsin K, calcitonin receptor, and of the sodium/hydrogen exchanger NHA2 were quantified by real-time PCR. The activity of newly formed osteoclasts was evaluated by means of a calcium phosphate resorption assay. Superficially adsorbed RANKL did not induce the formation of osteoclasts on β-TCP ceramics. When co-precipitated onto β-TCP ceramics RANKL supported the formation of mature osteoclasts. The development of osteoclast lineage cells was further confirmed by the increased expression of cathepsin K, calcitonin receptor, and NHA2. Incorporated RANKL stimulated the cells to resorb crystalline calcium phosphate. Our in vitro study shows that RANKL incorporated into β-TCP ceramics induces the formation of active, resorbing osteoclasts on the material surface. Once formed, osteoclasts mediate the release of RANKL thereby perpetuating their differentiation and activation. In vivo, the stimulation of osteoclast-mediated resorption may contribute to a coordinated sequence of material resorption and bone formation. Further in vivo studies

  3. On differences in radiosensitivity estimation: TCP experiments versus survival curves. A theoretical study

    Science.gov (United States)

    Stavrev, Pavel; Stavreva, Nadejda; Ruggieri, Ruggero; Nahum, Alan

    2015-08-01

    We have compared two methods of estimating the cellular radiosensitivity of a heterogeneous tumour, namely, via cell-survival and via tumour control probability (TCP) pseudo-experiments. It is assumed that there exists intra-tumour variability in radiosensitivity and that the tumour consists predominantly of radiosensitive cells and a small number of radio-resistant cells. Using a multi-component, linear-quadratic (LQ) model of cell kill, a pseudo-experimental cell-survival versus dose curve is derived. This curve is then fitted with a mono-component LQ model describing the response of a homogeneous cell population. For the assumed variation in radiosensitivity it is shown that the composite pseudo-experimental survival curve is well approximated by the survival curve of cells with uniform radiosensitivity. For the same initial cell radiosensitivity distribution several pseudo-experimental TCP curves are simulated corresponding to different fractionation regimes. The TCP model used accounts for clonogen proliferation during a fractionated treatment. The set of simulated TCP curves is then fitted with a mono-component TCP model. As in the cell survival experiment the fit with a mono-component model assuming uniform radiosensitivity is shown to be highly acceptable. However, the best-fit values of cellular radiosensitivity produced via the two methods are very different. The cell-survival pseudo-experiment yields a high radiosensitivity value, while the TCP pseudo-experiment shows that the dose-response is dominated by the most resistant sub-population in the tumour, even when this is just a small fraction of the total.

  4. Genome-Wide Identification, Characterization and Expression Analysis of the TCP Gene Family in Prunus mume.

    Science.gov (United States)

    Zhou, Yuzhen; Xu, Zongda; Zhao, Kai; Yang, Weiru; Cheng, Tangren; Wang, Jia; Zhang, Qixiang

    2016-01-01

    TCP proteins, belonging to a plant-specific transcription factors family, are known to have great functions in plant development, especially flower and leaf development. However, there is little information about this gene family in Prunus mume, which is widely cultivated in China as an ornamental and fruit tree. Here a genome-wide analysis of TCP genes was performed to explore their evolution in P. mume. Nineteen PmTCPs were identified and three of them contained putative miR319 target sites. Phylogenetic and comprehensive bioinformatics analyses of these genes revealed that different types of TCP genes had undergone different evolutionary processes and the genes in the same clade had similar chromosomal location, gene structure, and conserved domains. Expression analysis of these PmTCPs indicated that there were diverse expression patterns among different clades. Most TCP genes were predominantly expressed in flower, leaf, and stem, and showed high expression levels in the different stages of flower bud differentiation, especially in petal formation stage and gametophyte development. Genes in TCP-P subfamily had main roles in both flower development and gametophyte development. The CIN genes in double petal cultivars might have key roles in the formation of petal, while they were correlated with gametophyte development in the single petal cultivar. The CYC/TB1 type genes were highly detected in the formation of petal and pistil. The less-complex flower types of P. mume might result from the fact that there were only two CYC type genes present in P. mume and a lack of CYC2 genes to control the identity of flower types. These results lay the foundation for further study on the functions of TCP genes during flower development.

  5. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior.

    Science.gov (United States)

    Sweet, Lauren; Kang, Yunqing; Czisch, Christopher; Witek, Lukasz; Shi, Yang; Smay, Jim; Plant, Giles W; Yang, Yunzhi

    2015-01-01

    Numerous studies have demonstrated that Schwann cells (SCs) play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP) scaffolds arranged in 3D printed-lattice (P-β-TCP) and randomly-porous, template-casted (N-β-TCP) structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf), neutrophin-3 (nt-3), platelet-derived growth factor (pdgf-bb), and vascular endothelial growth factor (vegf-a) were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts.

  6. In vitro neurotoxic hazard characterization of different tricresyl phosphate (TCP) isomers and mixtures.

    Science.gov (United States)

    Duarte, Daniel J; Rutten, Joost M M; van den Berg, Martin; Westerink, Remco H S

    2016-02-03

    Exposure to tricresyl phosphates (TCPs), via for example contaminated cabin air, has been associated with health effects including the so-called aerotoxic syndrome. While TCP neurotoxicity is mainly attributed to ortho-isomers like tri-ortho-cresyl phosphate (ToCP), recent exposure and risk assessments indicate that ToCP levels in cabin air are very low. However, the neurotoxic potential of non-ortho TCP isomers and TCP mixtures is largely unknown. We therefore measured effects of exposure (up to 48h) to different TCP isomers, mixtures and the metabolite of ToCP (CBDP: cresyl saligenin phosphate) on cell viability and mitochondrial activity, spontaneous neuronal electrical activity, and neurite outgrowth in primary rat cortical neurons. The results demonstrate that exposure to TCPs (24-48h, up to 10μM) increases mitochondrial activity, without affecting cell viability. Effects of acute TCP exposure (30min) on neuronal electrical activity are limited. However, electrical activity is markedly decreased for the majority of TCPs (10μM) following 48h exposure. Additional preliminary data indicate that exposure to TCPs (48h, 10μM) did not affect the number of neurites per cell or average neurite length, except for TmCP and the analytical TCP mixture (Sigma) that induced a reduction of average neurite length. The combined neurotoxicity data demonstrate that the different TCPs, including ToCP, are roughly equipotent and a clear structure-activity relation is not apparent for the studied endpoints. The no-observed-effect-concentrations (1μM) are well above current exposure levels indicating limited neurotoxic health risk, although exposures may have been higher in the past. Moreover, prolonged and/or repeated exposure to TCPs may exacerbate the observed neurotoxic effects, which argues for additional research.

  7. The Arabidopsis thaliana TCP transcription factors: A broadening horizon beyond development.

    Science.gov (United States)

    Li, Shutian

    2015-01-01

    The TCP family of transcription factors is named after the first 4 characterized members, namely TEOSINTE BRANCHED1 (TB1) from maize (Zea mays), CYCLOIDEA (CYC) from snapdragon (Antirrhinum majus), as well as PROLIFERATING CELL NUCLEAR ANTIGEN FACTOR1 (PCF1) and PCF2 from rice (Oryza sativa). Phylogenic analysis of this plant-specific protein family unveils a conserved bHLH-containing DNA-binding motif known as the TCP domain. In accordance with the structure of this shared domain, TCP proteins are grouped into class I (TCP-P) and class II (TCP-C), which are suggested to antagonistically modulate plant growth and development via competitively binding similar cis-regulatory modules called site II elements. Over the last decades, TCPs across the plant kingdom have been demonstrated to control a plethora of plant processes. Notably, TCPs also regulate plant development and defense responses via stimulating the biosynthetic pathways of bioactive metabolites, such as brassinosteroid (BR), jasmonic acid (JA) and flavonoids. Besides, mutagenesis analysis coupled with biochemical experiments identifies several crucial amino acids located within the TCP domain, which confer the redox sensitivity of class I TCPs and determine the distinct DNA-binding properties of TCPs. In this review, developmental functions of TCPs in various biological pathways are briefly described with an emphasis on their involvement in the synthesis of bioactive substances. Furthermore, novel biochemical aspects of TCPs with respect to redox regulation and DNA-binding preferences are elaborated. In addition, the unexpected participation of TCPs in effector-triggered immunity (ETI) and defense against insects indicates that the widely recognized developmental regulators are capable of fine-tuning defense signaling and thereby enable plants to evade deleterious developmental phenotypes. Altogether, these recent impressive breakthroughs remarkably advance our understanding as to how TCPs integrate

  8. Solid state synthesis and thermal stability of HAP and HAP - beta-TCP composite ceramic powders.

    Science.gov (United States)

    Rao, R R; Roopa, H N; Kannan, T S

    1997-08-01

    Powders of pure beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HAP) and a biphasic composite mixture of HAP+beta-TCP were prepared by solid state reaction between two commercially available calcium-based precursors namely, tricalcium phosphate (TCP) and calcium hydroxide (Ca(OH)2). These reactants mixed in the molar ratios ranging from 3 : 0 to 3 : 4 (designated T0 to T4) in deionized water, milled and slip-cast into discs were heat treated in the temperature range of 600 degrees C to 1250 degrees C. The products formed were characterized by X-ray diffraction (XRD) and i.r. spectroscopic techniques for identification of phases formed and functional groups present in them. While tricalcium phosphate and calcium hydroxide taken in the molar ratio of 3 : 2 and 3 : 3 resulted in pure HAP when heat treated at 1000 degrees C for 8 h, the 3 : 1 and 3 : 1.5 molar ratio compositions resulted in a biphasic mixture of HAP+beta-TCP for similar heat treatments. Heat treatment of 3 : 4 molar ratio composition of tricalcium phosphate and calcium hydroxide at 1000 degrees C yielded HAP with free CaO as the secondary phase. Products of heat treatment at higher temperatures (1150 and 1250 degrees C) for even shorter duration (2 h) while not differing from the products obtained from T0 and T2 cases at 1000 degrees C (pure beta-TCP and pure HAP), change in the case of T1, T1.5, T3 and T4 to products with lesser percentages of HAP containing beta-TCP (in the case of T1 and T1.5) or CaO (in the case of T3 and T4) as the secondary phase.

  9. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior.

    Directory of Open Access Journals (Sweden)

    Lauren Sweet

    Full Text Available Numerous studies have demonstrated that Schwann cells (SCs play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP scaffolds arranged in 3D printed-lattice (P-β-TCP and randomly-porous, template-casted (N-β-TCP structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf, neutrophin-3 (nt-3, platelet-derived growth factor (pdgf-bb, and vascular endothelial growth factor (vegf-a were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts.

  10. Geometrical versus Random β-TCP Scaffolds: Exploring the Effects on Schwann Cell Growth and Behavior

    Science.gov (United States)

    Czisch, Christopher; Witek, Lukasz; Shi, Yang; Smay, Jim; Plant, Giles W.; Yang, Yunzhi

    2015-01-01

    Numerous studies have demonstrated that Schwann cells (SCs) play a role in nerve regeneration; however, their role in innervating a bioceramic scaffold for potential application in bone regeneration is still unknown. Here we report the cell growth and functional behavior of SCs on β-tricalcium phosphate (β-TCP) scaffolds arranged in 3D printed-lattice (P-β-TCP) and randomly-porous, template-casted (N-β-TCP) structures. Our results indicate that SCs proliferated well and expressed the phenotypic markers p75LNGFR and the S100-β subunit of SCs as well as displayed growth morphology on both scaffolds, but SCs showed spindle-shaped morphology with a significant degree of SCs alignment on the P-β-TCP scaffolds, seen to a lesser degree in the N-β-TCP scaffold. The gene expressions of nerve growth factor (β-ngf), neutrophin–3 (nt–3), platelet-derived growth factor (pdgf-bb), and vascular endothelial growth factor (vegf-a) were higher at day 7 than at day 14. While no significant differences in protein secretion were measured between these last two time points, the scaffolds promoted the protein secretion at day 3 compared to that on the cell culture plates. These results together imply that the β-TCP scaffolds can support SC cell growth and that the 3D-printed scaffold appeared to significantly promote the alignment of SCs along the struts. Further studies are needed to investigate the early and late stage relationship between gene expression and protein secretion of SCs on the scaffolds with refined characteristics, thus better exploring the potential of SCs to support vascularization and innervation in synthetic bone grafts. PMID:26444999

  11. Genome-Wide Identification, Characterization and Expression Analysis of the TCP Gene Family in Prunus mume

    Science.gov (United States)

    Zhou, Yuzhen; Xu, Zongda; Zhao, Kai; Yang, Weiru; Cheng, Tangren; Wang, Jia; Zhang, Qixiang

    2016-01-01

    TCP proteins, belonging to a plant-specific transcription factors family, are known to have great functions in plant development, especially flower and leaf development. However, there is little information about this gene family in Prunus mume, which is widely cultivated in China as an ornamental and fruit tree. Here a genome-wide analysis of TCP genes was performed to explore their evolution in P. mume. Nineteen PmTCPs were identified and three of them contained putative miR319 target sites. Phylogenetic and comprehensive bioinformatics analyses of these genes revealed that different types of TCP genes had undergone different evolutionary processes and the genes in the same clade had similar chromosomal location, gene structure, and conserved domains. Expression analysis of these PmTCPs indicated that there were diverse expression patterns among different clades. Most TCP genes were predominantly expressed in flower, leaf, and stem, and showed high expression levels in the different stages of flower bud differentiation, especially in petal formation stage and gametophyte development. Genes in TCP-P subfamily had main roles in both flower development and gametophyte development. The CIN genes in double petal cultivars might have key roles in the formation of petal, while they were correlated with gametophyte development in the single petal cultivar. The CYC/TB1 type genes were highly detected in the formation of petal and pistil. The less-complex flower types of P. mume might result from the fact that there were only two CYC type genes present in P. mume and a lack of CYC2 genes to control the identity of flower types. These results lay the foundation for further study on the functions of TCP genes during flower development. PMID:27630648

  12. Osteoconductivity and Biodegradability of Collagen Scaffold Coated with Nano-β-TCP and Fibroblast Growth Factor 2

    Directory of Open Access Journals (Sweden)

    Asako Ibara

    2013-01-01

    Full Text Available Nanoparticle bioceramics have become anticipated for biomedical applications. Highly bioactive and biodegradable scaffolds would be developed using nanoparticles of β-tricalcium phosphate (β-TCP. We prepared collagen scaffolds coated by nano-β-TCP and fibroblast growth factor 2 (FGF2 and evaluated the effects on new bone augmentation and biodegradation. The collagen sponge was coated with the nano-TCP dispersion and freeze-dried. Scaffold was characterized by SEM, TEM, XRD, compressive testing and cell seeding. Subsequently, the nano-β-TCP/collagen scaffold, collagen sponge, and each material loaded with FGF2 were implanted on rat cranial bone. As a control, no implantation was performed. Nano-TCP particles were found to be attached to the fibers of the collagen sponge by SEM and TEM observations. Scaffold coated with nano-TCP showed higher compressive strength and cytocompatibility. In histological evaluations at 10 days, inflammatory cells were rarely seen around the residual scaffold, suggesting that the nano-TCP material possesses good tissue compatibility. At 35 days, bone augmentation and scaffold degradation in histological samples receiving nano-β-TCP scaffold were significantly greater than those in the control. By loading of FGF2, advanced bone formation is facilitated, indicating that a combination with FGF2 would be effective for bone tissue engineering.

  13. Leaf expansion in Arabidopsis is controlled by a TCP-NGA regulatory module likely conserved in distantly related species.

    Science.gov (United States)

    Ballester, Patricia; Navarrete-Gómez, Marisa; Carbonero, Pilar; Oñate-Sánchez, Luis; Ferrándiz, Cristina

    2015-09-01

    The NGATHA (NGA) clade of transcription factors (TFs) forms a small subfamily of four members in Arabidopsis thaliana. NGA genes act redundantly to direct the development of apical tissues in the gynoecium, where they have been shown to be essential for style and stigma specification. In addition, NGA genes have a more general role in controlling lateral organ growth. The four NGA genes in Arabidopsis are expressed in very similar domains, although little is known about the nature of their putative regulators. Here, we have identified a conserved region within the four NGA promoters that we have used as a bait to screen a yeast library, aiming to identify such NGA regulators. Three members of the TCP family of TFs, named after the founding factors TEOSINTE BRANCHED 1, CYCLOIDEA and PROLIFERATING CELL FACTOR 1 AND 2), were recovered from this screening, of which two [TCP2 and TCP3, members of the CINCINNATA (CIN) family of TCP genes (CIN-TCP) subclade] were shown to activate the NGA3 promoter in planta. We provide evidence that support that CIN-TCP genes are true regulators of NGA gene expression, and that part of the CIN-TCP role in leaf development is mediated by NGA upregulation. Moreover, we have found that this TCP-NGA regulatory interaction is likely conserved in angiosperms, including important crop species, for which the regulation of leaf development is a target for biotechnological improvement.

  14. Reducing Communication Overhead by Scheduling TCP Transfers on Mobile Devices using Wireless Network Performance Maps

    DEFF Research Database (Denmark)

    Højgaard-Hansen, Kim; Madsen, Tatiana Kozlova; Schwefel, Hans-Peter

    2012-01-01

    The performance of wireless communication networks has been shown to have a strong location dependence. Measuring the performance while having accurate location information available makes it possible to generate performance maps. In this paper we propose a framework for the generation and use...... of such performance maps. We demonstrate how the framework can be used to reduce the retransmissions and to better utilise network resources when performing TCP-based file downloads in vehicular M2M communication scenarios. The approach works on top of a standard TCP stack hence has to map identified transmission...

  15. SCPS-TP, TCP, and Rate-Based Protocol Evaluation. Revised

    Science.gov (United States)

    Tran, Diepchi T.; Lawas-Grodek, Frances J.; Dimond, Robert P.; Ivancic, William D.

    2005-01-01

    Tests were performed at Glenn Research Center to compare the performance of the Space Communications Protocol Standard Transport Protocol (SCPS TP, otherwise known as "TCP Tranquility") relative to other variants of TCP and to determine the implementation maturity level of these protocols, particularly for higher speeds. The testing was performed over reasonably high data rates of up to 100 Mbps with delays that are characteristic of near-planetary environments. The tests were run for a fixed packet size, but for variously errored environments. This report documents the testing performed to date.

  16. CER/TER - The New Metric for TCP Connection Robustness Evaluation and Comparison

    Directory of Open Access Journals (Sweden)

    Ondrej Vondrous

    2015-01-01

    Full Text Available This article presents new metric for TCP connection robustness evaluation and comparison. This metric is focused on TCP connection and transmission continuity rather then on maximal throughput or minimal RTT. This metric is developed especially for evaluation of narrow band networks. That is why it is very convenient to use this metric for networks such as Internet of Things networks or industrial sensor networks. Our metric is based on observing if connections or transmissions are successfully finished or not. It is possible to optimize this metric for specific situations. This metric can be used in both the real networks and in discrete simulation environments.

  17. A New Approach for Performance Evaluation of TCP over Interference-Limited Wireless Channels

    Institute of Scientific and Technical Information of China (English)

    LUO Rui; FAN Pingzhi

    2003-01-01

    A new metric for performance evaluation of transport control protocol(TCP) over wireless channels based on the interference-limited characteristics of code division multiple address(CDMA) system is proposed. According to the new metric, the performance of TCP over CDMA correlated channel for different protocol parameters and different versions is investigated. The results show that appropriate selection of protocol parameters and packet error rate(PER) operation point can improve significantly the capacity of packet-switched CDMA-based network.

  18. TCP over low-power and lossy networks: tuning the segment size to minimize energy consumption

    CERN Document Server

    Ayadi, Ahmed; Ros, David

    2010-01-01

    Low-power and Lossy Networks (LLNs), like wireless networks based upon the IEEE 802.15.4 standard, have strong energy constraints, and are moreover subject to frequent transmission errors, not only due to congestion but also to collisions and to radio channel conditions. This paper introduces an analytical model to compute the total energy consumption in an LLN due to the TCP protocol. The model allows us to highlight some tradeoffs as regards the choice of the TCP maximum segment size, of the Forward Error Correction (FEC) redundancy ratio, and of the number of link-layer retransmissions, in order to minimize the total energy consumption.

  19. MULTIMEDIA DATA TRANSMISSION THROUGH TCP/IP USING HASH BASED FEC WITH AUTO-XOR SCHEME

    Directory of Open Access Journals (Sweden)

    R. Shalin

    2012-09-01

    Full Text Available The most preferred mode for communication of multimedia data is through the TCP/IP protocol. But on the other hand the TCP/IP protocol produces huge packet loss unavoidable due to network traffic and congestion. In order to provide a efficient communication it is necessary to recover the loss of packets. The proposed scheme implements Hash based FEC with auto XOR scheme for this purpose. The scheme is implemented through Forward error correction, MD5 and XOR for providing efficient transmission of multimedia data. The proposed scheme provides transmission high accuracy, throughput and low latency and loss.

  20. 10 Gbps TCP/IP streams from the FPGA for the CMS DAQ Eventbuilder Network

    CERN Document Server

    Bauer, Gerry; Branson, James; Chaze, Olivier; Cittolin, Sergio; Coarasa Perez, Jose Antonio; Darlea, Georgiana Lavinia; Deldicque, Christian; Dobson, Marc; Dupont, Aymeric; Erhan, Samim; Gigi, Dominique; Glege, Frank; Gomez Ceballos, Guillelmo; Gomez-Reino Garrido, Robert; Hartl, Christian; Hegeman, Jeroen Guido; Holzner, Andre Georg; Masetti, Lorenzo; Meijers, Franciscus; Meschi, Emilio; Mommsen, Remigius; Morovic, Srecko; Nunez Barranco Fernandez, Carlos; O'Dell, Vivian; Orsini, Luciano; Ozga, Wojciech Andrzej; Paus, Christoph Maria Ernst; Petrucci, Andrea; Pieri, Marco; Racz, Attila; Raginel, Olivier; Sakulin, Hannes; Sani, Matteo; Schwick, Christoph; Spataru, Andrei Cristian; Stieger, Benjamin Bastian; Sumorok, Konstanty; Veverka, Jan; Wakefield, Christopher Colin; Zejdl, Petr

    2013-01-01

    For the upgrade of the DAQ of the CMS experiment in 2013/2014 an interface between the custom detector Front End Drivers (FEDs) and the new DAQ eventbuilder network has to be designed. For a loss-less data collection from more then 600 FEDs a new FPGA based card implementing the TCP/IP protocol suite over 10Gbps Ethernet has been developed. We present the hardware challenges and protocol modifications made to TCP in order to simplify its FPGA implementation together with a set of performance measurements which were carried out with the current prototype.

  1. [Multi-bed & multi-parameter central monitoring system based on TCP/IP protocol].

    Science.gov (United States)

    Lian, S J; Hu, D K; Zhao, M H; Tang, L H

    2000-02-01

    Communication is one of the key problems to a central monitoring system. In this paper we put forward a central monitoring system using TCP/IP as the network protocol, Windows NT4.0 as the platform, forming a Intranet in a hospital. We also discussed the communication problem between the bed-side monitoring station and the central monitoring station in detail and then put forward a new protocol--Hospital Central Monitor Protocol (HCMP) based on TCP/IP to transfer monitoring data. It is easy to achieve tele-monitoring through the current communication subsystem.

  2. YottaYotta announces new world record set for TCP disk-to-disk bulk transfer

    CERN Multimedia

    2002-01-01

    The Yottabyte NetStorage(TM) Company, today announced a new world record for TCP disk-to-disk data transfer using the company's NetStorager(R) System. The record-breaking demonstration transferred 5 terabytes of data between Chicago, Il. to Vancouver, BC and Ottawa, ON, at a sustained average throughput of 11.1 gigabits per second. Peak throughput exceeded 11.6 gigabits per second, more than 15-times faster than previous records for TCP transfer from disk-to-disk (1 page).

  3. Effects of tcpB Mutations on Biogenesis and Function of the Toxin-Coregulated Pilus, the Type IVb Pilus of Vibrio cholerae.

    Science.gov (United States)

    Gao, Yang; Hauke, Caitlyn A; Marles, Jarrad M; Taylor, Ronald K

    2016-10-15

    Vibrio cholerae is the etiological agent of the acute intestinal disorder cholera. The toxin-coregulated pilus (TCP), a type IVb pilus, is an essential virulence factor of V. cholerae Recent work has shown that TcpB is a large minor pilin encoded within the tcp operon. TcpB contributes to efficient pilus formation and is essential for all TCP functions. Here, we have initiated a detailed targeted mutagenesis approach to further characterize this salient TCP component. We have identified (thus far) 20 residues of TcpB which affect either the steady-state level of TcpB or alter one or more TCP functions. This study provides a solid framework for further understanding of the complex role of TcpB and will be of use upon determination of the crystal structure of TcpB or related minor pilin orthologs of type IVb pilus systems. Type IV pili, such as the toxin-coregulated pilus (TCP) in V. cholerae, are bacterial appendages that often act as essential virulence factors. Minor pilins, like TcpB, of these pili systems often play integral roles in pilus assembly and function. In this study, we have generated mutations in tcpB to determine residues of importance for TCP stability and function. Combined with a predicted tertiary structure, characterization of these mutants allows us to better understand critical residues in TcpB and the role they may play in the mechanisms underlying minor pilin functions. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  4. Advanced TCP Port Scan and Its Response%TCP端口的高级扫描及其响应

    Institute of Scientific and Technical Information of China (English)

    孙海峰

    2005-01-01

    TCP端口扫描分为TCP Connect()、TCP SYN、TCP ACK、TCP FIN和TCP NULL等扫描.利用TCP头部6个1位标志字段,向目标主机端口发送带特殊标志字段的数据包,分析目标主机响应数据包TCP头部的6个1位标志字段的内容,得目标主机的端口状态.其编程用VC6.0及Winsock原始套接字实现.

  5. Performance Evaluation of DSDV and AODV Routing Protocols On The Basis Of TCP Variants in WSN and MANET

    Directory of Open Access Journals (Sweden)

    Shivangi Ranawat

    2014-01-01

    Full Text Available Transmission Control Protocol (TCP provides reliability to data transferring in all end-to-end data stream services on the internet. This protocol is utilized by major internet applications. TCP was originally created to handle the problem of network congestion collapse. This paper is prepared on the performance of different TCP variants to identify the best protocol variant for network expansion. In such context, a full comprehensive simulation environment is created for evaluating the comparative performance of TCP variants like TCP NewReno, SACK, FACK, RTCP and Vegas with the routing protocol AODV and DSDV in WSN and MANET. In this paper the overall performance of WSN and MANET is analyzed by comparing on the basis of Energy, End-to-End Delay, Throughput and Packet Delivery Ratio of the network.

  6. SATNET Development and Operation. Pluribus Satellite IMP Development, Remote Site Maintenance. Internet Development. Mobile Access Terminal Network, TCP for the HP3000, TCP-TAC.

    Science.gov (United States)

    1980-08-01

    7.2.3.4 Network Buffer Resources List Structures .... 64 8 TCP-TAC ............ . . . ............ 66 Report No. 4474 Bolt Beranek and Newman Inc. 1...circuit appeared to be due to a troublesome 9600 baud Codex modem at the London TIP. When malfunctioning, the modem hangs up in such a way that it performs...the modem momentarily in loopback mode. Site personnel have since replaced the Codex modem on the circuit in hopes of eliminating the problem. The high

  7. TCP/IP Protocol and Video Transfers on IP Multicast%TCP/IP协议和IP组播的视频传输

    Institute of Scientific and Technical Information of China (English)

    沈祖冀

    2001-01-01

    介绍介绍TCP/IP协议的有关内容。介绍IP组播,提出一种用IP组播的传输视频的解决方案和实现实例,此方案兼容现在的网络,有良好的视频信号传输效果。

  8. The Research of Covert Channels Based on TCP/IP%基于TCP/IP协议的网络隐蔽通道研究

    Institute of Scientific and Technical Information of China (English)

    徐杰锋

    2003-01-01

    首先基于TCP/IP网络协议中的安全缺陷,给出了4种建立网络隐蔽通道的基本方法;然后,分析了当前主流防火墙以及入侵检测系统对建立这些隐蔽通道的影响;最后,讨论了网络隐蔽通道的防范措施.

  9. 瓶颈网络TCP/主动队列管理模型及仿真%TCP/Active Queue Management Model and Simulation for Bottleneck Networks

    Institute of Scientific and Technical Information of China (English)

    曹振臻; 肖扬; 迟彩霞

    2009-01-01

    提出了一种基于离散时间Markov链的时延闭环反馈TCP/AQM(Active Queue Management)模型,并得到其稳态分布.通过以环路时延为单位,将系统时间分割成长度不同的时隙,分析每个时隙内TCP发送端发送窗口模型和瓶颈路由器队列模型.通过结合相邻时隙的参数,提出了TCP/AQM整体分析模型.该模型可以估计路由器的队列平均长度和丢包率、TCP发送端的平均发送窗口值,因此可以用于分析AQM算法性能以及给新算法的设计提供理论支持.通过在Matlab实施该模型与NS2仿真结果作比较,证实了该模型在模拟时延闭环反馈的TCP/RED系统的有效性.

  10. A Simulation Study on the Throughput Performance of TCP over Wireless Fading Channel

    Institute of Scientific and Technical Information of China (English)

    YAO Ling; JI Hong; YUE Guang-xin

    2004-01-01

    Using Markov model and the network simulator-NS, this paper studies the TCP throughput performance in wireless fading channel where the packets losses are always caused by high and burst errors. The results show that the burstiness in packet errors caused by slow multipath fading benefits Reno compared to i.i.d packet errors.

  11. A multiple time-scale model for TCP bandwidth sharing under user heterogeneity

    NARCIS (Netherlands)

    Abendroth, D.; Berg, J.L. van den; Mandjes, M.

    2005-01-01

    Building on the vast body of existing TCP models, we develop a novel versatile model that explicitly captures user heterogeneity, and takes into consideration dynamics at both the packet level and the flow level. It is described how the resulting multiple time-scale model can be numerically evaluate

  12. TCP Transcription Factors at the Interface between Environmental Challenges and the Plant’s Growth Responses

    Science.gov (United States)

    Danisman, Selahattin

    2016-01-01

    Plants are sessile and as such their reactions to environmental challenges differ from those of mobile organisms. Many adaptions involve growth responses and hence, growth regulation is one of the most crucial biological processes for plant survival and fitness. The plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, PCF1 (TCP) transcription factor family is involved in plant development from cradle to grave, i.e., from seed germination throughout vegetative development until the formation of flowers and fruits. TCP transcription factors have an evolutionary conserved role as regulators in a variety of plant species, including orchids, tomatoes, peas, poplar, cotton, rice and the model plant Arabidopsis. Early TCP research focused on the regulatory functions of TCPs in the development of diverse organs via the cell cycle. Later research uncovered that TCP transcription factors are not static developmental regulators but crucial growth regulators that translate diverse endogenous and environmental signals into growth responses best fitted to ensure plant fitness and health. I will recapitulate the research on TCPs in this review focusing on two topics: the discovery of TCPs and the elucidation of their evolutionarily conserved roles across the plant kingdom, and the variety of signals, both endogenous (circadian clock, plant hormones) and environmental (pathogens, light, nutrients), TCPs respond to in the course of their developmental roles. PMID:28066483

  13. CNoA: Challenging Number Approach for uncovering TCP SYN flooding using SYN spoofing attack

    CERN Document Server

    Kavisankar, L

    2011-01-01

    The challenging number is used for the detection of Spoofing attack. The IP Spoofing is considered to be one of the potentially brutal attack which acts as a tool for the DDoS attack which is considered to be a major threat among security problems in today's internet. These kinds of attack are extremely severe. They bring down business of company drastically. DDoS attack can easily exhaust the computing and communication resources of its victim within a short period of time. There are attacks exploiting some vulnerability or implementation bug in the software implementation of a service to bring that down and some attacks will use all the available resources at the target machine. This deals on attacks that consume all the bandwidth available to the victim machine. While concentrating on the bandwidth attack the TCP SYN flood is the more prominent attack. TCP/IP protocol suite is the most widely used protocol suite for data communication. The TCP SYN flood works by exhausting the TCP connection queue of the h...

  14. A Network Steganography Lab on Detecting TCP/IP Covert Channels

    Science.gov (United States)

    Zseby, Tanja; Vázquez, Félix Iglesias; Bernhardt, Valentin; Frkat, Davor; Annessi, Robert

    2016-01-01

    This paper presents a network security laboratory to teach data analysis for detecting TCP/IP covert channels. The laboratory is mainly designed for students of electrical engineering, but is open to students of other technical disciplines with similar background. Covert channels provide a method for leaking data from protected systems, which is a…

  15. TCP Transcription Factors at the Interface between Environmental Challenges and the Plant's Growth Responses.

    Science.gov (United States)

    Danisman, Selahattin

    2016-01-01

    Plants are sessile and as such their reactions to environmental challenges differ from those of mobile organisms. Many adaptions involve growth responses and hence, growth regulation is one of the most crucial biological processes for plant survival and fitness. The plant-specific TEOSINTE BRANCHED 1, CYCLOIDEA, PCF1 (TCP) transcription factor family is involved in plant development from cradle to grave, i.e., from seed germination throughout vegetative development until the formation of flowers and fruits. TCP transcription factors have an evolutionary conserved role as regulators in a variety of plant species, including orchids, tomatoes, peas, poplar, cotton, rice and the model plant Arabidopsis. Early TCP research focused on the regulatory functions of TCPs in the development of diverse organs via the cell cycle. Later research uncovered that TCP transcription factors are not static developmental regulators but crucial growth regulators that translate diverse endogenous and environmental signals into growth responses best fitted to ensure plant fitness and health. I will recapitulate the research on TCPs in this review focusing on two topics: the discovery of TCPs and the elucidation of their evolutionarily conserved roles across the plant kingdom, and the variety of signals, both endogenous (circadian clock, plant hormones) and environmental (pathogens, light, nutrients), TCPs respond to in the course of their developmental roles.

  16. Securing TCP/IP and Dial-up Access to Administrative Data.

    Science.gov (United States)

    Conrad, L. Dean

    1992-01-01

    This article describes Arizona State University's solution to security risk inherent in general access systems such as TCP/IP (Transmission Control Protocol/INTERNET Protocol). Advantages and disadvantages of various options are compared, and the process of selecting a log-on authentication approach involving generation of a different password at…

  17. MultiNet TCP/P/IP for VAX/VMS update

    Science.gov (United States)

    Vance, L. Stuart

    1991-01-01

    Outlines of device support; DECnet interoperability; installation; MultiNet services; domain name server; Telnet; FTP; SMTP; DECwindows over TCP/IP; BSD r services; remote printing; RPC services and NFS server; NFS client; netcontrol; diagnostics; programming support; and MultiNet features are presented in viewgraph format.

  18. Improving TCP Performance over Wireless Ad Hoc Networks with Busy Tone Assisted Scheme

    Directory of Open Access Journals (Sweden)

    Cai Lin

    2006-01-01

    Full Text Available It is well known that transmission control protocol (TCP performance degrades severely in IEEE 802.11-based wireless ad hoc networks. We first identify two critical issues leading to the TCP performance degradation: (1 unreliable broadcast, since broadcast frames are transmitted without the request-to-send and clear-to-send (RTS/CTS dialog and Data/ACK handshake, so they are vulnerable to the hidden terminal problem; and (2 false link failure which occurs when a node cannot successfully transmit data temporarily due to medium contention. We then propose a scheme to use a narrow-bandwidth, out-of-band busy tone channel to make reservation for broadcast and link error detection frames only. The proposed scheme is simple and power efficient, because only the sender needs to transmit two short messages in the busy tone channel before sending broadcast or link error detection frames in the data channel. Analytical results show that the proposed scheme can dramatically reduce the collision probability of broadcast and link error detection frames. Extensive simulations with different network topologies further demonstrate that the proposed scheme can improve TCP throughput by 23% to 150%, depending on user mobility, and effectively enhance both short-term and long-term fairness among coexisting TCP flows in multihop wireless ad hoc networks.

  19. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering.

    Science.gov (United States)

    Ardjomandi, N; Huth, J; Stamov, D R; Henrich, A; Klein, C; Wendel, H-P; Reinert, S; Alexander, D

    2016-10-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Delay Prediction for Real-Time Video Adaptive Transmisson over TCP

    Directory of Open Access Journals (Sweden)

    Yonghua Xiong

    2010-06-01

    Full Text Available Real-time multimedia streaming applications are increasingly using TCP instead of UCP as underlying transport protocol, however the great end-to-end delays are the major factor to influence the quality of streaming across the Internet using TCP. In this paper, we point the requirement for transmitting real-time video with acceptable playing performance via TCP and present a stochastic prediction model which can predict the sending-delays of video frames.  Based on the prediction model, we propose a real-time video adaptive transmission scheme which can dynamically adjust video frame rate and playout buffer size according to available network bandwidth. The scheme does not require any modifications to the network infrastructure or TCP protocol stack and only wants to measure some parameters including video frame size, loss ratio, congestion windows size, RTT and RTO time before video frames are sent. The performance of proposed prediction model and adaptive scheme are evaluated through extensive simulations using the NS-2 simulator.

  1. Performance of TCP-friendly streaming sessions in the presence of heavy-tailed elastic flows

    NARCIS (Netherlands)

    Bekker, R.; Borst, S.C.; Núñez Queija, R.

    2005-01-01

    We consider a fixed number of streaming sessions which share a bottleneck link with a dynamic population of elastic flows. Motivated by extensive measurement studies, we assume that the sizes of the elastic flows exhibit heavy-tailed characteristics. The elastic flows are TCP-controlled, while the t

  2. Truncated power control for improving TCP/IP performance over CDMA wireless links

    DEFF Research Database (Denmark)

    Cianca, Ernestina; Prasad, Ramjee; De Sanctis, Mauro

    2005-01-01

    The issue of the performance degradation of transmission control protocol/Internet Protocol (TCP/IP) over wireless links due to the presence of noncongestion-related packet losses has been addressed with a physical layer approach. The effectiveness of automatic repeat request techniques in enhanc...

  3. Specific surface area effect on adsorption of chlorpyrifos and TCP by soils and modeling

    Science.gov (United States)

    The adsorption of chlorpyrifos and TCP (3,5,6, trichloro-2-pyridinol) was determined in four soils (Mollisol, Inceptisol, Entisol, Alfisol) having different specific surface areas (19–84 m2/g) but rather similar organic matter content (2.4–3.5%). Adsorption isotherms were derived from batch equilibr...

  4. A fuzzy logic based network intrusion detection system for predicting the TCP SYN flooding attack

    CSIR Research Space (South Africa)

    Mkuzangwe, Nenekazi NP

    2017-04-01

    Full Text Available presents a fuzzy logic based network intrusion detection system to predict neptune which is a type of a Transmission Control Protocol Synchronized (TCP SYN) flooding attack. The performance of the proposed fuzzy logic based system is compared to that of a...

  5. TCP Performance over Wi-Fi: Joint Impact of Buffer and Channel Losses

    NARCIS (Netherlands)

    Pokhrel, S.R.; Panda, M.; Vu, H.L.; Mandjes, M.

    2016-01-01

    We propose an analytical model for a Wi-Fi network acting as a last-mile Internet access with multiple long-lived TCP connections on both the up and down links. Our model considers the joint impact of buffer losses at the access point, contention at the medium access control layer, and packet losses

  6. ComboCoding: Combined intra-/inter-flow network coding for TCP over disruptive MANETs

    Directory of Open Access Journals (Sweden)

    Chien-Chia Chen

    2011-07-01

    Full Text Available TCP over wireless networks is challenging due to random losses and ACK interference. Although network coding schemes have been proposed to improve TCP robustness against extreme random losses, a critical problem still remains of DATA–ACK interference. To address this issue, we use inter-flow coding between DATA and ACK to reduce the number of transmissions among nodes. In addition, we also utilize a “pipeline” random linear coding scheme with adaptive redundancy to overcome high packet loss over unreliable links. The resulting coding scheme, ComboCoding, combines intra-flow and inter-flow coding to provide robust TCP transmission in disruptive wireless networks. The main contributions of our scheme are twofold; the efficient combination of random linear coding and XOR coding on bi-directional streams (DATA and ACK, and the novel redundancy control scheme that adapts to time-varying and space-varying link loss. The adaptive ComboCoding was tested on a variable hop string topology with unstable links and on a multipath MANET with dynamic topology. Simulation results show that TCP with ComboCoding delivers higher throughput than with other coding options in high loss and mobile scenarios, while introducing minimal overhead in normal operation.

  7. Regulated intramembrane proteolysis of the virulence activator TcpP in Vibrio cholerae is initiated by the tail-specific protease (Tsp).

    Science.gov (United States)

    Teoh, Wei Ping; Matson, Jyl S; DiRita, Victor J

    2015-09-01

    Vibrio cholerae uses a multiprotein transcriptional regulatory cascade to control expression of virulence factors cholera toxin and toxin-co-regulated pilus. Two proteins in this cascade are ToxR and TcpP - unusual membrane-localized transcription factors with relatively undefined periplasmic domains and transcription activator cytoplasmic domains. TcpP and ToxR function with each other and two other membrane-localized proteins, TcpH and ToxS, to activate transcription of toxT, encoding the direct activator of toxin and pilus genes. Under some conditions, TcpP is degraded in a two-step proteolytic pathway known as regulated intramembrane proteolysis (RIP), thereby inactivating the cascade. The second step in this proteolytic pathway involves the zinc metalloprotease YaeL; V. cholerae cells lacking YaeL accumulate a truncated yet active form of TcpP termed TcpP*. We hypothesized that a protease acting prior to YaeL degrades TcpP to TcpP*, which is the substrate of YaeL. In this study, we demonstrate that a C-terminal protease called Tsp degrades TcpP to form TcpP*, which is then acted upon by YaeL. We present evidence that TcpH and Tsp serve to protect full-length TcpP from spurious proteolysis by YaeL. Cleavage by Tsp occurs in the periplasmic domain of TcpP and requires residues TcpPA172 and TcpPI174 for wild-type activity. © 2015 John Wiley & Sons Ltd.

  8. The Influences of Composition and Formula on α-TCP/β-TCP Phosphate Cement's Properties%α-TCP/β-TCP骨水泥组成及配比对性能的影响

    Institute of Scientific and Technical Information of China (English)

    史雪婷; 徐立新; 石宗利

    2006-01-01

    通过对α-TCP体系骨水泥固相粉末配方的优化,研究了不同重量比α-TCP/β-TCP粉末对两相骨水泥凝固时间和抗压强度的影响.结果表明粉末含有β-TCP时,骨水泥凝固时间更适合临床塑型,且β-TCP含量为20%时,抗压强度达52.98 MPa.

  9. Proliferation and osteogenic differentiation of human periodontal ligament cells on akermanite and β-TCP bioceramics

    Directory of Open Access Journals (Sweden)

    L Xia

    2011-07-01

    Full Text Available The purpose of this study was to investigate the effects of akermanite as compared to β-TCP on attachment, proliferation, and osteogenic differentiation of human periodontal ligament cells (hPDLCs. Scanning electron microscopy (SEM and actin filament labeling were used to reveal attachment and growth of hPDLCs seeded on β-TCP and akermanite ceramic. Cell proliferation was tested by lactic acid production and MTT analysis, while osteogenic differentiation was assayed by alkaline phosphatase (ALP expression and real-time polymerase chain reaction (PCR analysis on markers of osteopontin (OPN, dentin matrix acidic phosphoprotein-1 (DMP-1, and osteocalcin (OCN, and further detected by enzyme-linked immunosorbent analysis (ELISA analysis for OCN expression. Besides, the ions released from akermanite and their effect on hPDLCs was also measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES, MTT analysis, ALP expression and real-time PCR analysis. hPDLCs attached well on both ceramics, but showed better spreading on akermanite. hPDLCs proliferated more rapidly on akermanite than β-TCP. Importantly, osteogenic differentiation of hPDLCs was enhanced on akermanite compared to β-TCP. Besides, Ca, Mg and Si ions were released from akermanite, while only Ca ions were released from β-TCP. Moreover, more pronounced proliferation and higher osteogenic gene expression for hPDLCs cultured with akermanite extract were detected as compared to cells cultured on akermanite. Therefore, akermanite ceramic showed an enhanced effect on proliferation and osteogenic differentiation of hPDLCs, which might be attributed to the release of ions containing Ca, Mg and Si from the material. It is suggested that akermanite ceramics may serve as a potential material for periodontal bone regeneration.

  10. Misato Controls Mitotic Microtubule Generation by Stabilizing the TCP-1 Tubulin Chaperone Complex [corrected].

    Science.gov (United States)

    Palumbo, Valeria; Pellacani, Claudia; Heesom, Kate J; Rogala, Kacper B; Deane, Charlotte M; Mottier-Pavie, Violaine; Gatti, Maurizio; Bonaccorsi, Silvia; Wakefield, James G

    2015-06-29

    Mitotic spindles are primarily composed of microtubules (MTs), generated by polymerization of α- and β-Tubulin hetero-dimers. Tubulins undergo a series of protein folding and post-translational modifications in order to fulfill their functions. Defects in Tubulin polymerization dramatically affect spindle formation and disrupt chromosome segregation. We recently described a role for the product of the conserved misato (mst) gene in regulating mitotic MT generation in flies, but the molecular function of Mst remains unknown. Here, we use affinity purification mass spectrometry (AP-MS) to identify interacting partners of Mst in the Drosophila embryo. We demonstrate that Mst associates stoichiometrically with the hetero-octameric Tubulin Chaperone Protein-1 (TCP-1) complex, with the hetero-hexameric Tubulin Prefoldin complex, and with proteins having conserved roles in generating MT-competent Tubulin. We show that RNAi-mediated in vivo depletion of any TCP-1 subunit phenocopies the effects of mutations in mst or the Prefoldin-encoding gene merry-go-round (mgr), leading to monopolar and disorganized mitotic spindles containing few MTs. Crucially, we demonstrate that Mst, but not Mgr, is required for TCP-1 complex stability and that both the efficiency of Tubulin polymerization and Tubulin stability are drastically compromised in mst mutants. Moreover, our structural bioinformatic analyses indicate that Mst resembles the three-dimensional structure of Tubulin monomers and might therefore occupy the TCP-1 complex central cavity. Collectively, our results suggest that Mst acts as a co-factor of the TCP-1 complex, playing an essential role in the Tubulin-folding processes required for proper assembly of spindle MTs.

  11. Surface biofunctionalization of β-TCP blocks using aptamer 74 for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ardjomandi, N.; Huth, J. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Stamov, D.R. [JPK Instruments AG, Berlin (Germany); Henrich, A. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Klein, C. [Dental Practice Zahngesundheit Waiblingen, Waiblingen (Germany); Wendel, H.-P. [Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, Tübingen (Germany); Reinert, S. [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany); Alexander, D., E-mail: dorothea.alexander@med.uni-tuebingen.de [Department of Oral and Maxillofacial Surgery, University Hospital Tübingen (Germany)

    2016-10-01

    Successful bone regeneration following oral and maxillofacial surgeries depends on efficient functionalization strategies that allow the recruitment of osteogenic progenitor cells at the tissue/implant interface. We have previously identified aptamer 74, which exhibited a binding affinity for osteogenically induced jaw periosteal cells (JPCs). In the present study, this aptamer was used for the surface biofunctionalization of β-tricalcium phosphate (β-TCP) blocks. Atomic force microscopy (AFM) measurements showed increased binding activity of aptamer 74 towards osteogenically induced JPCs compared to untreated controls. The immobilization efficiency of aptamer 74 was analyzed using the QuantiFluor ssDNA assay for 2D surfaces and by amino acid analysis for 3D β-TCP constructs. Following the successful immobilization of aptamer 74 in 2D culture wells and on 3D constructs, in vitro assays showed no significant differences in cell proliferation compared to unmodified surfaces. Interestingly, JPC mineralization was significantly higher on the 2D surfaces and higher cell adhesion was detected on the 3D constructs with immobilized aptamer. Herein, we report an established, biocompatible β-TCP matrix with surface immobilization of aptamer 74, which enhances properties such as cell adhesion on 3D constructs and mineralization on 2D surfaces. Further studies need to be performed to improve the immobilization efficiency and to develop a suitable approach for JPC mineralization growing within 3D β-TCP constructs. - Highlights: • Covalent binding of aptamer 74 on PLGA-coated β-tricalcium phosphate constructs. • AFM analysis of rupture forces between aptamer 74 and jaw periosteal cells. • Analysis of jaw periosteal cell functions on aptamer coated β-TCP constructs.

  12. 基于TMS320VC5402的嵌入式TCP/IP协议栈实现%The design of embedded TCP/IP protocol stack based on TMS320V5402

    Institute of Scientific and Technical Information of China (English)

    廖天发

    2008-01-01

    基于数字信号处理器TMS320VC5402,实现一个小型嵌入式TCP/IP协议栈.介绍系统的硬件结构和以太网控制芯片RTL8019AS的接口电路设计,同时对TCP/IP协议中的IP协议、ARP协议、UDP协议进行分析,实现基于TCP/IP协议的嵌入式网络系统.

  13. Effect of amorphous phases during the hydraulic conversion of α-TCP into calcium-deficient hydroxyapatite.

    Science.gov (United States)

    Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

    2014-09-01

    Powders of α-tricalcium phosphate (α-TCP), which readily react with water to form calcium-deficient hydroxyapatite (CDHA), are frequently used in bone cements. As, for clinical applications, it is important to adjust the setting reaction of the cements to a reasonable reaction time, exact knowledge of the hydration mechanism is essential. It is known that prolonged milling results in partial amorphization of α-TCP powders and that dissolution of the amorphous phase significantly accelerates the hydration, but it is not clear yet when the amorphous phase reacts in comparison to the crystalline α-TCP. Therefore the aim of this study was to investigate the development of quantitative phase content of α-TCP samples during hydration. For this purpose, three α-TCP powders, containing 0, 16 and 71wt.% of amorphous phase (ATCP), were mixed with either deionized water or a 0.1M Na2HPO4 aqueous solution. The crystalline evolution of the paste was assessed quantitatively during the first 48h of hydration at 23°C by G-factor quantification. The present investigations demonstrate that ATCP reacted earlier than crystalline α-TCP. The results also suggest the formation of an X-ray amorphous phase during the hydraulic conversion formation of α-TCP into CDHA.

  14. Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice.

    Science.gov (United States)

    Scarano, Antonio; Ceccarelli, Maurizio; Marchetti, Massimiliano; Piattelli, Adriano; Mortellaro, Carmen

    2016-01-01

    Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase the biostimulating effect on fibroblasts and quicken resorption. Materials and Methods. Ten female, 6-8-week-old black-haired mice were selected. β-TCP/APG gel was injected into one cheek; the other was used as control. The animals were sacrificed at 8 weeks and histologically evaluated. Results. The new fibroblast was intensively stained with acid fuchsin and presented in contact with β-TCP. At higher magnification, actively secreting fibroblasts were observed at the periphery of β-TCP with a well differentiated fibroblast cell line and blood vessels. Acid fuchsin stained cutaneous structures in pink: no epidermal/dermal alterations or pathological inflammatory infiltrates were detected. The margins of β-TCP granules were clear and not diffused near tissues. Conclusion. APG with β-TCP preserves skin morphology, without immune response, with an excellent tolerability and is a promising scaffold for cells and biomaterial for soft tissue augmentation.

  15. Fabrication and characterization of a biodegradable Mg-2Zn-0.5Ca/1β-TCP composite.

    Science.gov (United States)

    Huang, Yan; Liu, Debao; Anguilano, Lorna; You, Chen; Chen, Minfang

    2015-09-01

    A biodegradable magnesium matrix and beta-tricalcium phosphate (β-TCP) particles reinforced composite Mg-2Zn-0.5Ca/1beta-TCP (wt.%) was fabricated for biomedical applications by the novel route of combined high shear solidification (HSS) and equal channel angular extrusion (ECAE). The as-cast composite obtained by HSS showed a fine and equiaxed grain structure with globally uniformly distributed β-TCP particles in aggregates of 2-25 μm in size. The ECAE processing at 300 °C resulted in further microstructural refinement and the improvement of β-TCP particle distribution. During ECAE, the β-TCP aggregates were broken into smaller ones or individual particles, forming a dispersion in the matrix. Such fabricated composite exhibited enhanced hardness and in vitro corrosion resistance. The enhanced hardness was attributed to both the addition of β-TCP particles and grain refinement while the development of a Ca-P rich surface layer from β-TCP during corrosion was responsible for the improvement in corrosion resistance. The composite was characterized in terms of microstructural evolution during fabrication, mechanical properties and electrochemical performance during polarization and immersion tests in a simulated body fluid. Discussions are made on the benefits of both HSS and ECAE and the mechanisms responsible for the enhanced corrosion resistance.

  16. PLGA/TCP composite scaffold incorporating bioactive phytomolecule icaritin for enhancement of bone defect repair in rabbits.

    Science.gov (United States)

    Chen, S-H; Lei, M; Xie, X-H; Zheng, L-Z; Yao, D; Wang, X-L; Li, W; Zhao, Z; Kong, A; Xiao, D-M; Wang, D-P; Pan, X-H; Wang, Y-X; Qin, L

    2013-05-01

    Bone defect repair is challenging in orthopaedic clinics. For treatment of large bone defects, bone grafting remains the method of choice for the majority of surgeons, as it fills spaces and provides support to enhance biological bone repair. As therapeutic agents are desirable for enhancing bone healing, this study was designed to develop such a bioactive composite scaffold (PLGA/TCP/ICT) made of polylactide-co-glycolide (PLGA) and tricalcium phosphate (TCP) as a basic carrier, incorporating a phytomolecule icaritin (ICT), i.e., a novel osteogenic exogenous growth factor. PLGA/TCP/ICT scaffolds were fabricated as PLGA/TCP (control group) and PLGA/TCP in tandem with low/mid/high-dose ICT (LICT/MICT/HICT groups, respectively). To evaluate the in vivo osteogenic and angiogenic potentials of these bioactive scaffolds with slow release of osteogenic ICT, the authors established a 12 mm ulnar bone defect model in rabbits. X-ray and high-resolution peripheral quantitative computed tomography results at weeks 2, 4 and 8 post-surgery showed more newly formed bone within bone defects implanted with PLGA/TCP/ICT scaffolds, especially PLGA/TCP/MICT scaffold. Histological results at weeks 4 and 8 also demonstrated more newly mineralized bone in PLGA/TCP/ICT groups, especially in the PLGA/TCP/MICT group, with correspondingly more new vessel ingrowth. These findings may form a good foundation for potential clinical validation of this innovative bioactive scaffold incorporated with the proper amount of osteopromotive phytomolecule ICT as a ready product for clinical applications.

  17. Understanding in vivo response and mechanical property variation in MgO, SrO and SiO₂ doped β-TCP.

    Science.gov (United States)

    Bose, Susmita; Tarafder, Solaiman; Banerjee, Shashwat S; Davies, Neal M; Bandyopadhyay, Amit

    2011-06-01

    The aim of this work is to evaluate the influence of MgO, SrO and SiO₂ doping on mechanical and biological properties of β-tricalcium phosphate (β-TCP) to achieve controlled resorption kinetics of β-TCP system for maxillofacial and spinal fusion application. We prepared dense TCP compacts of four different compositions, i) pure β-TCP, ii) β-TCP with 1.0wt.% MgO+1.0wt.% SrO, iii) β-TCP with 1.0wt.% SrO+0.5wt.% SiO₂, and iv) β-TCP with 1.0wt.% MgO+1.0wt.% SrO+0.5wt.% SiO₂, by uniaxial pressing and sintering at 1250°C. β phase stability is observed at 1250°C sintering temperature due to MgO doping in β-TCP. In vitro mineralization in simulated body fluid (SBF) for 16 weeks shows excellent apatite growth on undoped and doped samples. Strength degradation of TCP samples in SBF is significantly influenced by both dopant chemistry and amount of dopant. Compressive strengths for all samples show degradation in SBF over the 16 week time period with varying degradation kinetics. MgO/SrO/SiO₂ doped sample shows no strength loss, while undoped TCP shows the maximum strength loss from 419 ± 28 MPa to 158 ± 28 MPa over the 16 week study. In case of MgO/SrO doped TCP, strength loss is slow and gradual. TCP doped with 1.0wt.% MgO and 1.0wt.% SrO shows excellent in vivo biocompatibility when tested in male Sprague-Dawley rats for 16 weeks. Histomorphology analysis reveals that MgO/SrO doped TCP promoted osteogenesis by excellent early stage bone remodeling as compared to undoped TCP.

  18. 萍乡地区O139群霍乱弧菌TcpA基因序列分析%Gene Sequencing Analysis on Vibrio Cholera O139 Strains TcpA of Pingxiang Area

    Institute of Scientific and Technical Information of China (English)

    王长奇; 姚彬泉; 贺丁山; 陈燕萍; 罗娜; 周文峰

    2003-01-01

    目的探讨O139群霍乱JX株的TcpA基因序列,分析该株基因的特点.方法采用PCR扩增技术,检测含O139群霍乱标本,对TcpA基因阳性者进行核苷酸序列测定,分析基因变异情况.结果发现阳性标本中,对其中1株进行了TcpA基因序列测定,该序列与TcpAET(O139株)同源性为100%,与EVC序列同源性为96%.结论本株与O1群(EVC)遗传关系最近,对萍乡地区霍乱防治具有重要意义.

  19. A Randomized Clinical Trial Evaluating rh-FGF-2/β-TCP in Periodontal Defects.

    Science.gov (United States)

    Cochran, D L; Oh, T-J; Mills, M P; Clem, D S; McClain, P K; Schallhorn, R A; McGuire, M K; Scheyer, E T; Giannobile, W V; Reddy, M S; Abou-Arraj, R V; Vassilopoulos, P J; Genco, R J; Geurs, N C; Takemura, A

    2016-05-01

    Biological mediators have been used to enhance periodontal regeneration. The aim of this prospective randomized controlled study was to evaluate the safety and effectiveness of 3 doses of fibroblast growth factor 2 (FGF-2) when combined with a β-tricalcium phosphate (β-TCP) scaffold carrier placed in vertical infrabony periodontal defects in adult patients. In this double-blinded, dose-verification, externally monitored clinical study, 88 patients who required surgical intervention to treat a qualifying infrabony periodontal defect were randomized to 1 of 4 treatment groups-β-TCP alone (control) and 0.1% recombinant human FGF-2 (rh-FGF-2), 0.3% rh-FGF-2, and 0.4% rh-FGF-2 with β-TCP-following scaling and root planing of the tooth prior to a surgical appointment. Flap surgery was performed with EDTA conditioning of the root prior to device implantation. There were no statistically significant differences in patient demographics and baseline characteristics among the 4 treatment groups. When a composite outcome of gain in clinical attachment of 1.5 mm was used with a linear bone growth of 2.5 mm, a dose response pattern detected a plateau in the 0.3% and 0.4% rh-FGF-2/β-TCP groups with significant improvements over control and 0.1% rh-FGF-2/β-TCP groups. The success rate at 6 mo was 71% in the 2 higher-concentration groups, as compared with 45% in the control and lowest treatment groups. Percentage bone fill in the 2 higher-concentration groups was 75% and 71%, compared with 63% and 61% in the control and lowest treatment group. No increases in specific antibody to rh-FGF-2 were detected, and no serious adverse events related to the products were reported. The results from this multicenter trial demonstrated that the treatment of infrabony vertical periodontal defects can be enhanced with the addition of rh-FGF-2/β-TCP (ClinicalTrials.gov NCT01728844).

  20. Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP Synthesized from Porous Foraminifera Carbonate Macrospheres

    Directory of Open Access Journals (Sweden)

    Joshua Chou

    2013-12-01

    Full Text Available Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.

  1. Novel biodegradable α-TCP/poly(amino acid) composite artificial lamina following spinal surgery for prevention of intraspinal scar adhesion.

    Science.gov (United States)

    Ran, Bo; Song, Yue-Ming; Liu, Hao; Liu, Li-Min; Gong, Quan; Li, Tao; Zeng, Jian-Cheng; Yuan, Hai-Feng

    2011-12-01

    Biodegradable copolymer α-TCP/poly(amino acid) composite artificial lamina was prepared and used in goat cervical vertebra resection repair. Cervical 4 was removed by laminectomy, and a vertebra defect of 27 × 9 mm was made. α-TCP/poly(amino acid) composite artificial lamina was inserted in the test group. The efficiency of the copolymer during repair and reconstruction of the goats' vertebra was tested by using X-ray, CT scanning, and histological and biomechanical measurements. In the 24 weeks following the operation, the artificial lamina refrained from shifting, and no dural adhesion pressure was observed. In contrast, the control group suffered from infiltration of soft tissue in the spinal canal, dural pressure and α-TCP/poly(amino acid) degradation. In conclusion, α-TCP/poly(amino acid) composite artificial lamina can significantly prevent scar tissue from infiltrating the spinal canal.

  2. The effectiveness of the controlled release of simvastatin from β-TCP macrosphere in the treatment of OVX mice.

    Science.gov (United States)

    Chou, Joshua; Ito, Tomoko; Otsuka, Makoto; Ben-Nissan, Besim; Milthorpe, Bruce

    2016-03-01

    Simvastatin, a cholesterol treatment drug, has been shown to stimulate bone regeneration. As such, there has been an increase interest in the development of suitable materials and systems for the delivery of simvastatin. Without the appropriate dosage of simvastatin, the therapeutic effects on bone growth will be significantly reduced. Furthermore, similar to many pharmaceutical compounds, at high concentration simvastatin can cause various adverse side-effects. Given the associated side-effects with the usage of simvastatin, the development of suitable controlled drug release system is pertinent. Calcium phosphate in particularly beta-tricalcium phosphate (β-TCP) has been extensively studied and used as a carrier material for drug delivery system. In this study, Foraminifera exoskeletons were used as calcium carbonate precursor materials, which were hydrothermally converted to β-TCP as a carrier material for simvastatin. Natural marine exoskeletons posses interconnected and uniformly porous network capable of improving drug loading and release rate. To prolong the release of simvastatin, an apatite coating was made around the β-TCP sample and in vitro release studies in simulated body fluid (SBF) showed a significant decrease in release rate. Osteoporotic mice were used to examine the compare therapeutic effectiveness of β-TCP, β-TCP with simvastatin, apatite-coated β-TCP with simvastatin and direct injection of simvastatin near the right femur of the mice. Localized and systemic effect were compared with the femur of the non-implanted side (left) and showed that β-TCP with or without simvastatin was able to induce significant bone formation over 6 weeks. Mechanical analysis showed that apatite-coated β-TCP with simvastatin produced significantly stronger bones compared with other experimental groups. This study shows that natural exoskeletons with the appropriate structure can be successfully used as a drug delivery system for simvastatin and can its

  3. Soft Tissue Augmentation with Autologous Platelet Gel and β-TCP: A Histologic and Histometric Study in Mice

    OpenAIRE

    2016-01-01

    Background. Facial aging is a dynamic process involving both soft tissue and bony structures. Skin atrophy, with loss of tone, elasticity, and distribution of facial fat, coupled with gravity and muscle activity, leads to wrinkling and folds. Purpose. The aim of the study was to evaluate microporous tricalcium phosphate (β-TCP) and autologous platelet gel (APG) mix in mice for oral and maxillofacial soft tissue augmentation. The hypothesis was that β-TCP added with APG was able to increase th...

  4. Design of the Congestion Control for TCP/AQM Network with Time-Delay

    Directory of Open Access Journals (Sweden)

    Dazhong Wang

    2014-01-01

    Full Text Available The purpose of this paper is to design congestion controller for TCP/AQM (transmission control protocol/active queue management networks using model following control; the equilibrium of a class of TCP/AQM networks with time-delay is investigated, and the effect of communication time-delay on the stability is addressed. The features of this design method are bounded property of the internal states of the control system being given and the utility of this control. Such design exhibits important attributes including fast convergence with high accuracy to a desired queue length. Simulation results show that the time-delay nonlinear behavior of the system can be controlled by this method.

  5. MAC-layer protocol for TCP fairness in Wireless Mesh Networks

    KAUST Repository

    Nawab, Faisal

    2012-08-01

    In this paper we study the interactions of TCP and IEEE 802.11 MAC in Wireless Mesh Networks (WMNs). We use a Markov chain to capture the behavior of TCP sessions, particularly the impact on network throughput performance due to the effect of queue utilization and packet relaying. A closed form solution is derived to numerically determine the throughput. Based on the developed model, we propose a distributed MAC protocol to alleviate the unfairness problem in WMNs. Our protocol uses the age of packet as a priority metric for packet scheduling. Simulation is conducted to validate our model and to illustrate the fairness characteristics of our proposed MAC protocol. We conclude that we can achieve fairness with only little impact on network capacity.

  6. Active Queue Management in TCP Networks Based on Fuzzy-Pid Controller

    Directory of Open Access Journals (Sweden)

    Hossein ASHTIANI

    2012-01-01

    Full Text Available We introduce a novel and robust active queue management (AQM scheme based on a fuzzy controller, called hybrid fuzzy-PID controller. In the TCP network, AQM is important to regulate the queue length by passing or dropping the packets at the intermediate routers. RED, PI, and PID algorithms have been used for AQM. But these algorithms show weaknesses in the detection and control of congestion under dynamically changing network situations. In this paper a novel Fuzzy-based proportional-integral derivative (PID controller, which acts as an active queue manager (AQM for Internet routers, is proposed. These controllers are used to reduce packet loss and improve network utilization in TCP/IP networks. A new hybrid controller is proposed and compared with traditional RED based controller. Simulations are carried out to demonstrate the effectiveness of the proposed method and show that, the new hybrid fuzzy PID controller provides better performance than random early detection (RED and PID controllers

  7. Approaches in highly parameterized inversion - GENIE, a general model-independent TCP/IP run manager

    Science.gov (United States)

    Muffels, Christopher T.; Schreuder, Willem A.; Doherty, John E.; Karanovic, Marinko; Tonkin, Matthew J.; Hunt, Randall J.; Welter, David E.

    2012-01-01

    GENIE is a model-independent suite of programs that can be used to generally distribute, manage, and execute multiple model runs via the TCP/IP infrastructure. The suite consists of a file distribution interface, a run manage, a run executer, and a routine that can be compiled as part of a program and used to exchange model runs with the run manager. Because communication is via a standard protocol (TCP/IP), any computer connected to the Internet can serve in any of the capacities offered by this suite. Model independence is consistent with the existing template and instruction file protocols of the widely used PEST parameter estimation program. This report describes (1) the problem addressed; (2) the approach used by GENIE to queue, distribute, and retrieve model runs; and (3) user instructions, classes, and functions developed. It also includes (4) an example to illustrate the linking of GENIE with Parallel PEST using the interface routine.

  8. TCP/IP Interface for the Satellite Orbit Analysis Program (SOAP)

    Science.gov (United States)

    Carnright, Robert; Stodden, David; Coggi, John

    2009-01-01

    The Transmission Control Protocol/ Internet protocol (TCP/IP) interface for the Satellite Orbit Analysis Program (SOAP) provides the means for the software to establish real-time interfaces with other software. Such interfaces can operate between two programs, either on the same computer or on different computers joined by a network. The SOAP TCP/IP module employs a client/server interface where SOAP is the server and other applications can be clients. Real-time interfaces between software offer a number of advantages over embedding all of the common functionality within a single program. One advantage is that they allow each program to divide the computation labor between processors or computers running the separate applications. Secondly, each program can be allowed to provide its own expertise domain with other programs able to use this expertise.

  9. ESTRATEGIA PARA EL PRONÓSTICO DEL RTO DE FAST TCP, MEDIANTE LÓGICA DIFUSA

    Directory of Open Access Journals (Sweden)

    Carlos Peña

    2013-07-01

    Full Text Available Este artículo presenta el diseño y la simulación de una estrategia para el pronóstico del temporizador de retransmisión del algoritmo de control de la congestión FAST TCP. La estrategia utiliza la técnica de inteligencia computacional denominada lógica difusa. Los resultados de la simulación demuestran que a través de esta nueva forma de pronóstico del RTO, FAST TCP hace un mejor seguimiento a la situación real de congestión de la red, en el marco de una conexión entre dos extremos de la misma.

  10. On Designing Lyapunov-Krasovskii Based AQM for Routers Supporting TCP Flows

    CERN Document Server

    Labit, Yann; Gouaisbaut, Frédéric; 10.1109/CDC.2007.4434673

    2009-01-01

    For the last few years, we assist to a growing interest of designing AQM (Active Queue Management) using control theory. In this paper, we focus on the synthesis of an AQM based on the Lyapunov theory for time delay systems. With the help of a recently developed Lyapunov-Krasovskii functional and using a state space representation of a linearized fluid model of TCP, two robust AQMs stabilizing the TCP model are constructed. Notice that our results are constructive and the synthesis problem is reduced to a convex optimization scheme expressed in terms of linear matrix inequalities (LMIs). Finally, an example extracted from the literature and simulations via {\\it NS simulator} support our study.

  11. Fuzzy-Logic Adaptive Queuing for a Heuristic TCP Performance in Mobile Wireless Networks

    Directory of Open Access Journals (Sweden)

    Ghaida A. AL-Suhail

    2012-06-01

    Full Text Available In this paper, we propose a new Fuzzy-Logic Adaptive Queuing controller (FLAQ based on a classical Random Early Detection (RED algorithm in wireless cellular network. The controller predicts dynamically the packet dropping rate and the corresponding average queue length. It relies on the average queue length at the base station router and the packet loss rate caused by the channel variations in mobile environment; assuming there is no buffer overflow due to the congestion. Using this model, a heuristic TCP performance can be estimated over a time-varying channel under different conditions of user’s mobility. The results show a significant improvement in TCP throughput performance when the user’s mobility is below 5 m/s; and becomes constant (i.e., close to i.i.d beyond this speed especially at 5% of predefined packet error rate.

  12. How Equalization Techniques Affect the TCP Performance of MC-CDMA Systems in Correlated Fading Channels

    Directory of Open Access Journals (Sweden)

    Giacomo Leonardi

    2007-12-01

    Full Text Available This paper investigates the impact of several equalization techniques for multicarrier code division multiple access systems on the performance at both lower and upper layers (i.e., physical and TCP layers. Classical techniques such as maximal ratio combining, equal gain combining, orthogonality restoring combining, minimum mean square error, as well as a partial equalization (PE are investigated in time- and frequency-correlated fading channels with various numbers of interferers. Their impact on the performance at upper level is then studied. The results are obtained through an integrated simulation platform carefully reproducing all main aspects affecting the quality of service perceived by the final user, allowing an investigation of the real gain produced by signal processing techniques at TCP level.

  13. On the impact of TCP and per-flow scheduling on Internet performance (extended version)

    CERN Document Server

    Carofiglio, Giovanna

    2009-01-01

    Internet performance is tightly related to the properties of TCP and UDP protocols, jointly responsible for the delivery of the great majority of Internet traffic. It is well understood how these protocols behave under FIFO queuing and what the network congestion effects. However, no comprehensive analysis is available when flow-aware mechanisms such as per-flow scheduling and dropping policies are deployed. Previous simulation and experimental results leave a number of unanswered questions. In the paper, we tackle this issue by modeling via a set of fluid non-linear ODEs the instantaneous throughput and the buffer occupancy of N long-lived TCP sources under three per-flow scheduling disciplines (Fair Queuing, Longest Queue First, Shortest Queue First) and with longest queue drop buffer management. We study the system evolution and analytically characterize the stationary regime: closed-form expressions are derived for the stationary throughput/sending rate and buffer occupancy which give thorough understandi...

  14. REAL TIME TCP/IP CONTROL OF MODULAR PRODUCTION SYSTEMS WITH FPGAS

    Directory of Open Access Journals (Sweden)

    A. Castillo-Atoche

    2007-04-01

    Full Text Available The Modular Production System (MPS can be used to reproduce nearly any function in complex manufacturing processes. In this work a different way of real time TCP/IP control of three different MPS controlled by embedded processors inside a FPGA is proposed. The digital design with FPGA is particularly advantageous due to its parallel processing made possible by its flexible structure, high integration and velocity. The TCP/IP control is carried out with a Rabbit Core microprocessor. This device contains the functions required to implement a web server allowing the remote control of the MPS. A user enters a public IP direction on a designed web page to enable/disable each independent manufacturing process.

  15. TRAP: A Three-Way Handshake Server for TCP Connection Establishment

    Directory of Open Access Journals (Sweden)

    Fu-Hau Hsu

    2016-11-01

    Full Text Available Distributed denial of service attacks have become more and more frequent nowadays. In 2013, a massive distributed denial of service (DDoS attack was launched against Spamhaus causing the service to shut down. In this paper, we present a three-way handshaking server for Transmission Control Protocol (TCP connection redirection utilizing TCP header options. When a legitimate client attempted to connect to a server undergoing an SYN-flood DDoS attack, it will try to initiate a three-way handshake. After it has successfully established a connection, the server will reply with a reset (RST packet, in which a new server address and a secret is embedded. The client can, thus, connect to the new server that only accepts SYN packets with the corrected secret using the supplied secret.

  16. ML-IKE: a multi-layer IKE protocol for TCP performance enhancement in wireless networks

    Science.gov (United States)

    Zhang, Ya-Hang; Cheng, Bo-Wen; Qing, Si-Han; Zou, Guang-Nan; Wen, Wei-Ping

    2009-12-01

    To solve the conflict between TCP accelerating technology based on PEP middle node and IPSec protocol used in the Satellite Network, NASA and the Hughes Research Laboratory (HRL) each independently proposed a solution named Multilayer IPsec protocol which can integrate IPSec with TCP PEPs. The problem is: Traditional IKE protocol can't work with Multilayer IPSec protocol. In this study, the traditional IKE main mode and quick mode are enhanced for layered IPSec protocol, and an improved layered key distribution protocol: ML-IKE is proposed. This key distribution protocol is used for key exchange between peers and middle node, so that different nodes have different security associations (SA), and different security associations correspond to different IP packet fields, so different SA nodes have different authorization to different IP packet fields. ML-IKE protocol is suitable for layered IPSec, thus layered IPSec can be used for automatic key distribution and update.

  17. A TCP/IP transport layer for the DAQ of the CMS experiment

    CERN Document Server

    Kozlovszky, Miklos

    2004-01-01

    The CMS collaboration is currently investigating various networking technologies that may meet the requirements of the CMS Data Acquisition System (DAQ). During this study, a peer transport component based on TCP/IP has been developed using object-oriented techniques for the distributed DAQ framework named XDAQ. This framework has been designed to facilitate the development of distributed data acquisition systems within the CMS Experiment. The peer transport component has to meet 3 main requirements. Firstly, it had to provide fair access to the communication medium for competing applications. Secondly, it had to provide as much of the available bandwidth to the application layer as possible. Finally, it had to hide the complexity of using non-blocking TCP/IP connections from the application layer. This paper describes the development of the peer transport component and then presents and draws conclusions on the measurements made during tests. The major topics investigated include: blocking versus non-blockin...

  18. Satellite communication on pipeline supervision using TCP-IP Protocol; Comunicacao via satelite na supervisao de dutos usando o protocolo TCP-IP

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Agliberto Pessoa da [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Brunette, Sergio Henrique de Moraes

    2003-07-01

    Bit transparent type or X-25 protocols have been used in VSAT satellite communication by PETROBRAS pipeline Supervisory Control and Data Acquisition System (SCADA) as access protocol. Both solutions have inconveniences. By the first one, difficulties exist for analysis and diagnosis of connection flaws, and therefore, for a ready identification by the system management stations of abnormality location. On the other hand, the usage of the X-25 brings an additional over-head in the communication since this is not an available option in most of the equipment that compose the SCADA. The access to VSAT through Ethernet, in the opposite, makes available all networks management tools of the TCP/IP platform and it allows a direct connection to the field devices, since the main models of the several makers of Programmable Controllers and Remote Terminal Units have Ethernet port. An additional earnings is the possibility of standardization that this solution allows. This paper describes a series of communication tests between two Programmable Controllers communicating through the satellite, using a protocol over Ethernet/TCP/IP. (author)

  19. On the long time behavior of the TCP window size process

    National Research Council Canada - National Science Library

    Chafaï, Djalil; Malrieu, Florent; Paroux, Katy

    2010-01-01

    ... TCP window size process. This process has [ 0 , ∞ ) as state space and its infinitesimal generator is given, for any smooth function f : [ 0 , ∞ ) → R , by (1) L ( f ) ( x ) = f ′ ( x ) + x ∫ 0 1 ( f ( h x ) − f ( x ) ) H ( d h ) for some probability measure H supported in [ 0 , 1 ) . This window size ( X t ) t increases linearl...

  20. TCP SYN Flood攻击和防御的分析

    Institute of Scientific and Technical Information of China (English)

    聂涛

    2006-01-01

    TCP SYN Flood(TCP同步洪水攻击)是目前最流行的DoS(拒绝服务攻击)与DDoS的方式之一,这是一种利用TCP协议缺陷,破坏TCP三次握手建立正常连接,从而使得被攻击方资源耗尽的攻击方式。

  1. Fabrication of 3D porous SF/β-TCP hybrid scaffolds for bone tissue reconstruction.

    Science.gov (United States)

    Park, Hyun Jung; Min, Kyung Dan; Lee, Min Chae; Kim, Soo Hyeon; Lee, Ok Joo; Ju, Hyung Woo; Moon, Bo Mi; Lee, Jung Min; Park, Ye Ri; Kim, Dong Wook; Jeong, Ju Yeon; Park, Chan Hum

    2016-07-01

    Bio-ceramic is a biomaterial actively studied in the field of bone tissue engineering. But, only certain ceramic materials can resolve the corrosion problem and possess the biological affinity of conventional metal biomaterials. Therefore, the recent development of composites of hybrid composites and polymers has been widely studied. In this study, we aimed to select the best scaffold of silk fibroin and β-TCP hybrid for bone tissue engineering. We fabricated three groups of scaffold such as SF (silk fibroin scaffold), GS (silk fibroin/small granule size of β-TCP scaffold) and GM (silk fibroin/medium granule size of β-TCP scaffold), and we compared the characteristics of each group. During characterization of the scaffold, we used scanning electron microscopy (SEM) and a Fourier transform infrared spectroscopy (FTIR) for structural analysis. We compared the physiological properties of the scaffold regarding the swelling ratio, water uptake and porosity. To evaluate the mechanical properties, we examined the compressive strength of the scaffold. During in vitro testing, we evaluated cell attachment and cell proliferation (CCK-8). Finally, we confirmed in vivo new bone regeneration from the implanted scaffolds using histological staining and micro-CT. From these evaluations, the fabricated scaffold demonstrated high porosity with good inter-pore connectivity, showed good biocompatibility and high compressive strength and modulus. In particular, the present study indicates that the GM scaffold using β-TCP accelerates new bone regeneration of implanted scaffolds. Accordingly, our scaffold is expected to act a useful application in the field of bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1779-1787, 2016.

  2. Spectroscopic classification of TCP J00390015+4028580 as a red long-period variable

    Science.gov (United States)

    Williams, S. C.; Darnley, M. J.

    2016-11-01

    We obtained a spectrum of M31 nova candidate TCP J00390015+4028580 (see CBAT TOCP) with the low-resolution (R 350) SPRAT spectrograph (Piascik et al. 2014) on the 2-m Liverpool Telescope (Steele et al. 2004) on 2016 November 1.93 UT. The spectrum is red and shows deep TiO absorption bands, along with narrow H & alpha; and H & beta; emission lines.

  3. Liverpool Telescope Spectrum of TCP J01375892+4951055 - A Dwarf Nova in the Andromeda Constellation

    Science.gov (United States)

    Darnley, M. J.; Williams, S. C.; Bode, M. F.

    2016-10-01

    We obtained an optical spectrum of TCP J01375892+4951055 (see CBAT TOCP) with the FRODOSpec spectrograph (Barnsley et al. 2012) on the 2.0m Liverpool Telescope (Steele et al. 2004) on 2016 October 20.06 UT. The spectrum was taken using the lower resolution mode of FRODOSpec, which gives a wavelength coverage of 3900 to 5700 Å and 5800 to 9400 Å, with a resolution of R ~ 2400.

  4. Communication-Gateway Software For NETEX, DECnet, And TCP/IP

    Science.gov (United States)

    Keith, B.; Ferry, D.; Fendler, E.

    1990-01-01

    Communications gateway software, GATEWAY, provides process-to-process communication between remote applications programs in different protocol domains. Communicating peer processes may be resident on any paired combination of NETEX, DECnet, or TCP/IP hosts. Provides necessary mapping from one protocol to another and facilitates practical intermachine communications in cost-effective manner by eliminating need to standardize on single protocol or to implement multiple protocols in host computers. Written in Ada.

  5. Re-Thinking the TCP Congestion Control Design in Network Simulators

    OpenAIRE

    Hume, Allison

    2016-01-01

    In contrast to live hardware testbeds, which are evaluated largely on performance, network simulators are primarily used to test and validate new protocols and algorithms. As such, a network simulator should be designed to be modular, extensible, re-usable, and robust. This work examines the design of TCP congestion control in the ns-3 network simulator and presents a new design, not specific to ns-3, that will be more modular and extensible. We also demonstrate that the implementation in the...

  6. Sliding Modes for Anomaly Observation in TCP Networks: From Theory to Practice

    OpenAIRE

    Rahme, Sandy; Labit, Yann; Gouaisbaut, Frédéric; Floquet, Thierry

    2013-01-01

    International audience; Anomaly detection has been an active open problem in the networks community for several years. In this brief, we aim at detecting such abnormal signals by control theory techniques. Several classes of sliding mode observers are proposed for a fluid flow model of the transmission control protocol (TCP)/internet protocol network. Comparative simulations via network simulator NS-2 show the enhancement brought by a higher order sliding mode observer. The efficiency of this...

  7. TINY TCP/IP PROTOCOL SUITE FOR EMBEDDED SYSTEMS WITH 32 BIT MICROCONTROLLER

    OpenAIRE

    Mr. Praful M. Godhankar; Mr. Maske Vishnu Dattatraya; Prof. Shahzia Sayyad

    2015-01-01

    The scope of embedded devices is increasing day by day and the demand will be further more when networking technology is incorporated into these devices. Many embedded systems not only communicate with each other, but also with computers using a network. All systems connected to the Internet, wireless networks such as WLAN and GPRS, and many local area networks communicate using the standard TCP/IP protocol suite. An embedded system may have as little memory, the memory constraints make progr...

  8. Context Aware TCP for Intelligence, Surveillance and Reconnaissance Missions on Autonomous Platforms

    Science.gov (United States)

    2014-10-08

    that was sampled several hundred times each 200ms, a Matlab moving average was implemented using a moving convolution function . Figure 11 shows a...achieving improved average throughput of asymmetric links, such as are seen in the context of RPA ISR missions. Keywords—RPA, UAV, SUAS, TCP, ISR...shows the performance differences and how this improvement could enhance effective throughput. This scenario was also simulated using Matlab and

  9. Enhanced Critical Size Defect Repair in Rabbit Mandible by Electrospun Gelatin/β-TCP Composite Nanofibrous Membranes

    Directory of Open Access Journals (Sweden)

    Mingming Xu

    2015-01-01

    Full Text Available The design and fabrication of biodegradable barrier membranes with satisfactory structure and composition remain a considerable challenge for periodontal tissue regeneration. We have developed a biomimetic nanofibrous membrane made from a composite of gelatin and β-tricalcium phosphate (β-TCP. We previously confirmed the in vitro biological performance of the membrane material, but the efficacy of the membranes in promoting bone repair in situ has not yet been examined. Gelatin/β-TCP composite nanofibers were fabricated by incorporation of 20 wt.% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite membranes presented a nonwoven structure with an interconnected porous network and had a rough surface due to the β-TCP nanoparticles, which were distributed widely and uniformly throughout the gelatin-fiber matrix. The repair efficacy of rabbit mandible defects implanted with bone substitute (Bio-Oss and covered with the gelatin/β-TCP composite nanofibrous membrane was evaluated in comparison with pure gelatin nanofibrous membrane. Gross observation, histological examination, and immunohistochemical analysis showed that new bone formation and defect closure were significantly enhanced by the composite membranes compared to the pure gelatin ones. From these results, we conclude that nanofibrous gelatin/β-TCP composite membranes could serve as effective barrier membranes for guided tissue regeneration.

  10. Variation of mechanical behavior of β-TCP/collagen two phase composite scaffold with mesenchymal stem cell in vitro.

    Science.gov (United States)

    Arahira, Takaaki; Todo, Mitsugu

    2016-08-01

    The primary aim of this study is to characterize the variational behavior of the compressive mechanical property of bioceramic-based scaffolds using stem cells during the cell culture period. β-Tricalcium phosphate (TCP)/collagen two phase composites and β-TCP scaffolds were fabricated using the polyurethane template technique and a subsequent freeze-drying method. Rat bone-marrow mesenchymal stem cells (rMSCs) were then cultured in these scaffolds for up to 28 days. Compression tests of the scaffolds with rMSCs were periodically conducted. Biological properties, such as the cell number, alkaline phosphatase (ALP) activity, and gene expressions of osteogenesis, were evaluated. The microstructural change due to cell growth and the formation of extracellular matrices was examined using a field-emission scanning electron microscope. The compressive property was then correlated with the biological properties and microstructures to understand the mechanism of the variational behavior of the macroscopic mechanical property. The porous collagen structure in the β-TCP scaffold effectively improved the structural stability of the composite scaffold, whereas the β-TCP scaffold exhibited structural instability with the collapse of the porous structure when immersed in a culture medium. The β-TCP/collagen composite scaffold exhibited higher ALP activity and more active generation of osteoblastic markers than the β-TCP scaffold.

  11. Enhanced interaction of Vibrio cholerae virulence regulators TcpP and ToxR under oxygen-limiting conditions.

    Science.gov (United States)

    Fan, Fenxia; Liu, Zhi; Jabeen, Nusrat; Birdwell, L Dillon; Zhu, Jun; Kan, Biao

    2014-04-01

    Vibrio cholerae is the causative agent of the diarrheal disease cholera. The ability of V. cholerae to colonize and cause disease requires the intricately regulated expression of a number of virulence factors during infection. One of the signals sensed by V. cholerae is the presence of oxygen-limiting conditions in the gut. It has been shown that the virulence activator AphB plays a key role in sensing low oxygen concentrations and inducing the transcription of another key virulence activator, TcpP. In this study, we used a bacterial two-hybrid system to further examine the effect of oxygen on different virulence regulators. We found that anoxic conditions enhanced the interaction between TcpP and ToxR, identified as the first positive regulator of V. cholerae virulence genes. We further demonstrated that the TcpP-ToxR interaction was dependent on the primary periplasmic protein disulfide formation enzyme DsbA and cysteine residues in the periplasmic domains of both ToxR and TcpP. Furthermore, we showed that in V. cholerae, an interaction between TcpP and ToxR is important for virulence gene induction. Under anaerobic growth conditions, we detected ToxR-TcpP heterodimers, which were abolished in the presence of the reducing agent dithiothreitol. Our results suggest that V. cholerae may sense intestinal anoxic signals by multiple components to activate virulence.

  12. Modulation of release kinetics by plasma polymerization of ampicillin-loaded β-TCP ceramics

    Science.gov (United States)

    Labay, C.; Buxadera-Palomero, J.; Avilés, M.; Canal, C.; Ginebra, M. P.

    2016-08-01

    Beta-tricalcium phosphate (β-TCP) bioceramics are employed in bone repair surgery. Their local implantation in bone defects puts them in the limelight as potential materials for local drug delivery. However, obtaining suitable release patterns fitting the required therapeutics is a challenge. Here, plasma polymerization of ampicillin-loaded β-TCP is studied for the design of a novel antibiotic delivery system. Polyethylene glycol-like (PEG-like) coating of β-TCP by low pressure plasma polymerization was performed using diglyme as precursor, and nanometric PEG-like layers were obtained by simple and double plasma polymerization processes. A significant increase in hydrophobicity, and the presence of plasma polymer was visible on the surface by SEM and quantified by XPS. As a main consequence of the plasma polymerisation, the release kinetics were successfully modified, avoiding burst release, and slowing down the initial rate of release leading to a 4.5 h delay in reaching the same antibiotic release percentage, whilst conservation of the activity of the antibiotic was simultaneously maintained. Thus, plasma polymerisation on the surface of bioceramics may be a good strategy to design controlled drug delivery matrices for local bone therapies.

  13. The Tissue Implant Response Surrounding Subcutaneous TCP, HA, And ALCAP Bioceramics.

    Science.gov (United States)

    Butler, K R; Benghuzzi, Hamed; Tucci, Michelle; Puckett, A D

    2015-01-01

    The objective of this investigation was to quantify and further elucidate the tissue-implant response in the fibrous tissue surrounding tricalcium phosphate (TCP), hydroxyapatite (HA), and aluminum calcium phosphate (ALCAP) implants when implanted subcutaneously. Sixteen animals in four experimental groups (n = 4/group) were implanted with one implant each: Group I (control, TCP), Group II (HA), and Group III (ALCAP). At 90 days post-implantation, the fibrous tissue surrounding the implants was harvested. Sections of stained fibrous tissue were evaluated for the presence of macrophages, fibrocytes, neutrophils, vascularity and thickness for all three groups using semi-automated quantitative methods. The analysis indicated Group III demonstrated a significantly higher number of neutrophils but fewer macrophages and blood vessels per high power field and had a substantially thinner fibrous tissue capsule thickness compared to Groups I and II (alpha=0.05). Group II elicited a greater response of fibroblasts compared to Groups I and III suggesting HA may provide a slightly higher degree of stability to the implant. In total, these findings suggest both TCP and HA behave similarly in vivo when compared to ALCAP and may be better choices for subcutaneous soft-tissue application compared to ALCAP.

  14. Release Kinetics and Antibacterial Efficacy of Microporous β-TCP Coatings

    Directory of Open Access Journals (Sweden)

    Michael Seidenstuecker

    2013-01-01

    Full Text Available Purpose. The aim of this study was to impregnate microporous β-TCP scaffolds with different antibiotic solutions and to determine their release behavior. Materials and Methods. We impregnated a β-TCP scaffold with antibiotics by using three methods: drop, dip, and stream coating with 120 mg/mL of antibiotic solution. After drying for 72 h at 37°C, 2 mL of distilled water was added to the antibiotic-coated plugs and incubated at 37°C. After defined time points (1, 2, 3, 6, 9, and 14 days, the liquid was completely replaced. The extracted liquid was analyzed by capillary zone electrophoresis and the Kirby Bauer disc diffusion test. For statistical analysis, we calculated a mean and standard deviation and carried out an analysis of variance using ANOVA. Results. The VAN and CLI release from the β-TCP scaffolds was rapid, occurring within 24 h with 89 ± 0.8% VAN and 90.4 ± 1.5% CLI regardless of the type of insulation. After six days, the VAN and CLI were completely released. All samples taken at later time points had a VAN or CLI concentration below the detection limit of 4 µg/mL. The released amounts of VAN and CLI within the first three days revealed antimicrobial activity.

  15. TCP throughput adaptation in WiMax networks using replicator dynamics.

    Science.gov (United States)

    Anastasopoulos, Markos P; Petraki, Dionysia K; Kannan, Rajgopal; Vasilakos, Athanasios V

    2010-06-01

    The high-frequency segment (10-66 GHz) of the IEEE 802.16 standard seems promising for the implementation of wireless backhaul networks carrying large volumes of Internet traffic. In contrast to wireline backbone networks, where channel errors seldom occur, the TCP protocol in IEEE 802.16 Worldwide Interoperability for Microwave Access networks is conditioned exclusively by wireless channel impairments rather than by congestion. This renders a cross-layer design approach between the transport and physical layers more appropriate during fading periods. In this paper, an adaptive coding and modulation (ACM) scheme for TCP throughput maximization is presented. In the current approach, Internet traffic is modulated and coded employing an adaptive scheme that is mathematically equivalent to the replicator dynamics model. The stability of the proposed ACM scheme is proven, and the dependence of the speed of convergence on various physical-layer parameters is investigated. It is also shown that convergence to the strategy that maximizes TCP throughput may be further accelerated by increasing the amount of information from the physical layer.

  16. Performance Analysis and Enhancement of TCP in Presence of Jitter in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Goudru N.G

    2016-06-01

    Full Text Available In wireless networks two types of losses namely congestion loss and transmission loss are significant. One of the important transmission losses is jitter. Variation in inter-arrival time is called jitter. When jitter value is greater than half of the average round trip time cause timeout loss and sender window size falls to one packet resulting reduction in throughput and degradation in the quality of service (QoS. In this paper, we are discussing a new model for transmission control protocol (TCP which is capable of changing its window size based on the feedback. In the new model TCP is added with intelligence so that it can distinguish the type of losses. If the loss is due to congestion, congestion control algorithm is invoked and loss is due to jitter immediate-recovery algorithm is invoked to recover from the throughput loss. The technique also provides an end-to-end congestion control. The performance of TCP is further enhanced by discussing stability. Time-delay control theory is applied for the analysis of asymptotic stability. The stability boundaries of random early detection (RED control parameter Pmax and jitter control parameter β are derived. Using the characteristic equation of Hermite matrix an approximate solution of q(t (queue length which converges to a given target value is derived. The results are analyzed based on graphs and statistical data using Matlab R2009b.

  17. Microfibrous {beta}-TCP/collagen scaffolds mimic woven bone in structure and composition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Shen; Zhang Xin; Cai Qing; Yang Xiaoping [Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Wang Bo; Deng Xuliang, E-mail: yangxp@mail.buct.edu.c [Department of VIP Dental Service, School and Hospital of Stomatology, Peking University, Beijing 100081 (China)

    2010-12-15

    Woven bone, as the initial form of bone tissue, is always found in developing and repairing bone. It is thought of as a temporary scaffold for the deposition of osteogenic cells and the laying down of lamellar bone. Thus, we hypothesize that a matrix which resembles the architecture and components of woven bone can provide an osteoblastic microenvironment for bone cell growth and new bone formation. In this study, woven-bone-like beta-tricalcium phosphate ({beta}-TCP)/collagen scaffolds were fabricated by sol-gel electrospinning and impregnating methods. Optimization studies on sol-gel synthesis and electrospinning process were conducted respectively to prepare pure {beta}-TCP fibers with dimensions close to mineralized collagen fibrils in woven bone. The collagen-coating layer prepared by impregnation had an adhesive role that held the {beta}-TCP fibers together, and resulted in rapid degradation and matrix mineralization in in vitro tests. MG63 osteoblast-like cells seeded on the resultant scaffolds showed three-dimensional (3D) morphologies, and merged into multicellular layers after 7 days culture. Cytotoxicity test further revealed that extracts from the resultant scaffolds could promote the proliferation of MG63 cells. Therefore, the woven-bone-like matrix that we constructed favored the attachment and proliferation of MG63 cells in three dimensions. It has great potential ability to shorten the time of formation of new bone.

  18. Performance of TCP/IP/ UDP adaptive header compression algorithm for wireless network

    Directory of Open Access Journals (Sweden)

    Prof.N.Penchalaiah

    2010-08-01

    Full Text Available The convergence of mobile technologies will characterize the future telecommunication systems based on TCP/IP protocols. These Protocols can be used to build both wired and wireless parts on same platform. But TCP/IP headers overheads are large, so it utilizes more bandwidth even small services, whose payload is small. So it definitely needheader compression to save bandwidth, as we know bandwidth is the most expensive and scared resource in wireless systems.There are many approaches used to compress the headers overloads. Most commonly used approaches are, an adaptive robust TCP/IP header compression lgorithm for 3G wireless networks and an adaptive robust header compression algorithm based on UDP-RTS/CTS handshake for real-timestreams in wireless networks such a 3G platforms. But these approaches are not efficient in adaptive nature. So In this paper we are proposing one approach to solve the problem efficiently even in adaptive nature. The aim of this algorithm is to adjust the dimension of Variable Sliding Window (VSW in W-LSB encoding with the accurate estimation of wireless channel state to achieve the good balance of compression ratio and error-resistant robustness for the adaptive use in wireless link. We present simulation results that demonstrate theeffectiveness of this adaptive algorithm over wireless link and comparative study of existing approaches

  19. Optimizing TCP Performance in Multi-AP Residential Broadband Connections via Minislot Access

    Directory of Open Access Journals (Sweden)

    Domenico Giustiniano

    2013-01-01

    Full Text Available The high bandwidth demand of Internet applications has recently driven the need of increasing the residential download speed. A practical solution to the problem is to aggregate the bandwidth of 802.11 access points (APs backhauls in range. Since 802.11 devices are usually single radio, the communication to APs on different radio channels requires a time-division multiple access (TDMA policy at the client station. With an in-depth experimental analysis and a customized 802.11 driver, in this paper, we show that the usage of multi-AP TDMA policy may cause degradation of the TCP throughput and an underutilization of the AP backhauls. We then introduce a simple analytical model that accurately predicts the TCP round-trip time (RTT with a multi-AP TDMA policy and propose a resource allocation algorithm to reduce the observed TCP RTT with a very low computational cost. Our proposed scheme runs locally at the client station and improves the aggregate throughput up to 1.5 times compared to state-of-the-art allocations. We finally show that the throughput achieved by our algorithm is very close to the theoretical upper bound in key simulation scenarios.

  20. Research on TCP High Availability Technology for Embedded Network Device%嵌入式网络设备TCP高可用技术研究

    Institute of Scientific and Technical Information of China (English)

    程友清; 余少华

    2013-01-01

    This paper focus on research of TCP high availability technology for embedded double controller network device or virtual cluster switch system in data communication network. It puts forward a new TCP high availability scheme, which only makes a small amount of modification of the TCP/IP protocol stack and upper layer TCP applications. The master synchronizes TCP connection information to slave only when the TCP connection was established or closed, the TCP/IP protocol stack in slave card or device uses the received TCP synchronization information to create or close the TCP socket and store the TCP connection information into TCP control block (TCPCB), then inform the TCP socket information to upper layer TCP applications to handle. When master crashes for some reason, the slave will change to master immediately, the synchronized TCP connection on the new master initializes its TCP control block information, such as send packet sequence number and receive packet sequence number, when receives the first TCP packet of the TCP socket. After that the TCP connection has been switched successfully, the upper layer TCP applications then send or receive packet as a normal TCP connection. The scheme described above has been used in practice on high-end Ethernet switch and router developed by the author's team, the test results and practical application show that the TCP high availability scheme consumed a small a-mount of communication bandwidth to synchronize the TCP connection information from master to slave and achieved microsecond level switchover of TCP connection when master card or device going down.%对数据网络中嵌入式双主控设备和虚拟集群交换系统的TCP高可用技术进行了研究.提出一种新的TCP高可用方案,该方案对TCP/IP协议栈和TCP应用软件做少量改动.主用设备只需在TCP连接建立或关闭时向备用发送TCP连接同步信息,备用设备上TCP/IP栈收到同步信息后强制创建或关闭TCP套接字并

  1. Potential implications of the bystander effect on TCP and EUD when considering target volume dose heterogeneity.

    Science.gov (United States)

    Balderson, Michael J; Kirkby, Charles

    2015-01-01

    In light of in vitro evidence suggesting that radiation-induced bystander effects may enhance non-local cell killing, there is potential for impact on radiotherapy treatment planning paradigms such as the goal of delivering a uniform dose throughout the clinical target volume (CTV). This work applies a bystander effect model to calculate equivalent uniform dose (EUD) and tumor control probability (TCP) for external beam prostate treatment and compares the results with a more common model where local response is dictated exclusively by local absorbed dose. The broad assumptions applied in the bystander effect model are intended to place an upper limit on the extent of the results in a clinical context. EUD and TCP of a prostate cancer target volume under conditions of increasing dose heterogeneity were calculated using two models: One incorporating bystander effects derived from previously published in vitro bystander data ( McMahon et al. 2012 , 2013a); and one using a common linear-quadratic (LQ) response that relies exclusively on local absorbed dose. Dose through the CTV was modelled as a normal distribution, where the degree of heterogeneity was then dictated by changing the standard deviation (SD). Also, a representative clinical dose distribution was examined as cold (low dose) sub-volumes were systematically introduced. The bystander model suggests a moderate degree of dose heterogeneity throughout a target volume will yield as good or better outcome compared to a uniform dose in terms of EUD and TCP. For a typical intermediate risk prostate prescription of 78 Gy over 39 fractions maxima in EUD and TCP as a function of increasing SD occurred at SD ∼ 5 Gy. The plots only dropped below the uniform dose values for SD ∼ 10 Gy, almost 13% of the prescribed dose. Small, but potentially significant differences in the outcome metrics between the models were identified in the clinically-derived dose distribution as cold sub-volumes were introduced. In terms of

  2. Understanding the influence of MgO and SrO binary doping on the mechanical and biological properties of beta-TCP ceramics.

    Science.gov (United States)

    Banerjee, Shashwat S; Tarafder, Solaiman; Davies, Neal M; Bandyopadhyay, Amit; Bose, Susmita

    2010-10-01

    The objective of this study was to evaluate the influence of MgO and SrO doping on the mechanical and biological properties of beta-tricalcium phosphate (beta-TCP). beta-TCP was doped with two different binary compositions, 0.25 and 1.0wt.% SrO along with 1.0wt.% MgO. MgO and SrO doping increased the beta phase stability at a sintering temperature of 1250 degrees C and marginally decreased the compressive strength of beta-TCP. An in vitro cell-material interaction study, using human fetal osteoblast cells (hFOB), indicated that doped beta-TCP was non-toxic, and MgO/SrO dopants improved cell attachment and growth. beta-TCP implants doped with 1.0wt.% MgO and 1.0wt.% SrO showed good in vivo biocompatibility when tested in male Sprague-Dawley rats for 16 weeks. Histomorphology analysis indicated that MgO/SrO-doped beta-TCP promoted more osteogenesis than pure beta-TCP. In vivo osteocalcin and type I collagen assay also revealed faster bone formation in rats with doped beta-TCP implant compared to rats with pure beta-TCP implant. Low Ca(2+) concentration in the urine of rats with doped beta-TCP implant confirmed slower degradation of MgO/SrO-doped beta-TCP than pure beta-TCP. 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Human Urine Derived Stem Cells in Combination with β-TCP Can Be Applied for Bone Regeneration.

    Directory of Open Access Journals (Sweden)

    Junjie Guan

    Full Text Available Bone tissue engineering requires highly proliferative stem cells that are easy to isolate. Human urine stem cells (USCs are abundant and can be easily harvested without using an invasive procedure. In addition, in our previous studies, USCs have been proved to be able to differentiate into osteoblasts, chondrocytes, and adipocytes. Therefore, USCs may have great potential and advantages to be applied as a cell source for tissue engineering. However, there are no published studies that describe the interactions between USCs and biomaterials and applications of USCs for bone tissue engineering. Therefore, the objective of the present study was to evaluate the interactions between USCs with a typical bone tissue engineering scaffold, beta-Tricalcium Phosphate (β-TCP, and to determine whether the USCs seeded onto β-TCP scaffold can promote bone regeneration in a segmental femoral defect of rats. Primary USCs were isolated from urine and seeded on β-TCP scaffolds. Results showed that USCs remained viable and proliferated within β-TCP. The osteogenic differentiation of USCs within the scaffolds was demonstrated by increased alkaline phosphatase activity and calcium content. Furthermore, β-TCP with adherent USCs (USCs/β-TCP were implanted in a 6-mm critical size femoral defect of rats for 12 weeks. Bone regeneration was determined using X-ray, micro-CT, and histologic analyses. Results further demonstrated that USCs in the scaffolds could enhance new bone formation, which spanned bone defects in 5 out of 11 rats while β-TCP scaffold alone induced modest bone formation. The current study indicated that the USCs can be used as a cell source for bone tissue engineering as they are compatible with bone tissue engineering scaffolds and can stimulate the regeneration of bone in a critical size bone defect.

  4. Response of human bone marrow-derived MSCs on triphasic Ca-P substrate with various HA/TCP ratio.

    Science.gov (United States)

    Bajpai, Indu; Kim, Duk Yeon; Kyong-Jin, Jung; Song, In-Hwan; Kim, Sukyoung

    2017-01-01

    Calcium phosphates (Ca-P) are used commonly as artificial bone substitutes to control the biodegradation rate of an implant in the body fluid. This study examined the in vitro proliferation of human bone marrow-derived mesenchymal stem cells (hBMSCs) on triphasic Ca-P samples. For this aspect, hydroxyapatite (HA), dicalcium phosphate dehydrate (DCPD), and calcium hydroxide (Ca(OH)2 ) were mixed at various ratios, cold compacted, and sintered at 1250°C in air. X-ray diffraction showed that the β-tricalcium phosphate (TCP) to α-TCP phase transformation increased with increasing DCPD/HA ratio. The micro-hardness deceased with increasing TCP content, whereas the mean grain size and porosity increased with increasing TCP concentration. To evaluate the in vitro degree of adhesion and proliferation on the HA/TCP samples, human BMSCs were incubated on the HA/TCP samples and analyzed by a cells proliferation assay, expression of the extracellular matrix (ECM) genes, such as α-smooth muscle actin (α-SMA) and fibronectin (FN), and FITC-phalloidin fluorescent staining. In terms of the interactions of human BMSCs with the triphasic Ca-P samples, H50T50 (Ca/P = 1.59) markedly enhanced cell spreading, proliferation, FN, and α-SMA compared with H100T0 (Ca/P = 1.67). Interestingly, these results show that among the five HA/TCP samples, H50T50 is the optimal Ca-P composition for in vitro cell proliferation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 72-80, 2017.

  5. Human Urine Derived Stem Cells in Combination with β-TCP Can Be Applied for Bone Regeneration.

    Science.gov (United States)

    Guan, Junjie; Zhang, Jieyuan; Li, Haiyan; Zhu, Zhenzhong; Guo, Shangchun; Niu, Xin; Wang, Yang; Zhang, Changqing

    2015-01-01

    Bone tissue engineering requires highly proliferative stem cells that are easy to isolate. Human urine stem cells (USCs) are abundant and can be easily harvested without using an invasive procedure. In addition, in our previous studies, USCs have been proved to be able to differentiate into osteoblasts, chondrocytes, and adipocytes. Therefore, USCs may have great potential and advantages to be applied as a cell source for tissue engineering. However, there are no published studies that describe the interactions between USCs and biomaterials and applications of USCs for bone tissue engineering. Therefore, the objective of the present study was to evaluate the interactions between USCs with a typical bone tissue engineering scaffold, beta-Tricalcium Phosphate (β-TCP), and to determine whether the USCs seeded onto β-TCP scaffold can promote bone regeneration in a segmental femoral defect of rats. Primary USCs were isolated from urine and seeded on β-TCP scaffolds. Results showed that USCs remained viable and proliferated within β-TCP. The osteogenic differentiation of USCs within the scaffolds was demonstrated by increased alkaline phosphatase activity and calcium content. Furthermore, β-TCP with adherent USCs (USCs/β-TCP) were implanted in a 6-mm critical size femoral defect of rats for 12 weeks. Bone regeneration was determined using X-ray, micro-CT, and histologic analyses. Results further demonstrated that USCs in the scaffolds could enhance new bone formation, which spanned bone defects in 5 out of 11 rats while β-TCP scaffold alone induced modest bone formation. The current study indicated that the USCs can be used as a cell source for bone tissue engineering as they are compatible with bone tissue engineering scaffolds and can stimulate the regeneration of bone in a critical size bone defect.

  6. Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility.

    Science.gov (United States)

    Swain, S K; Gotman, I; Unger, R; Gutmanas, E Y

    2017-09-01

    In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The degradation behavior of the developed composite materials was studied by immersion in Ringer's and saline solutions for up to 1month. The mechanical properties, before and after immersion, were tested in compression and bending. All the compositions exhibited high mechanical strength, the strength in bending being several fold higher than that of polymer toughened β-TCP-30PLA nanocomposites prepared by the similar procedure of attrition milling and cold sintering, and of pure high-temperature sintered β-TCP. Partial substitution of iron with silver led to an increase in both strength and ductility. Furthermore, the galvanic action of silver particles dispersed in the iron phase significantly accelerated in vitro degradation of β-TCP-30(Fe-Ag) nanocomposites. After 1month immersion, the composites retained about 50% of their initial bending strength. In cell culture experiments, β-TCP-27Fe3Ag nanocomposites exhibited no signs of cytotoxicity towards human osteoblasts suggesting that they can be used as an implant material. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Performance analysis of TCP traffic and its influence on ONU's energy saving in energy efficient TDM-PON

    Science.gov (United States)

    Alaelddin, Fuad Yousif Mohammed; Newaz, S. H. Shah; Lee, Joohyung; Uddin, Mohammad Rakib; Lee, Gyu Myoung; Choi, Jun Kyun

    2015-12-01

    The majority of the traffic over the Internet is TCP based, which is very sensitive to packet loss and delay. Existing research efforts in TDM-Passive Optical Networks (TDM-PONs) mostly evaluate energy saving and traffic delay performances under different energy saving solutions. However, to the best of our knowledge, how energy saving mechanisms could affect TCP traffic performance in TDM-PONs has hardly been studied. In this paper, by means of our state-of-art OPNET Modular based TDM-PON simulator, we evaluate TCP traffic delay, throughput, and Optical Network Unit (ONU) energy consumption performances in a TDM-PON where energy saving mechanisms are employed in ONUs. Here, we study the performances under commonly used energy saving mechanisms defined in standards for TDM-PONs: cyclic sleep and doze mode. In cyclic sleep mode, we evaluate the performances under two well-known sleep interval length deciding algorithms (i.e. fixed sleep interval (FSI) and exponential sleep interval deciding (ESID)) that an OLT uses to decide sleep interval lengths for an ONU. Findings in this paper put forward the strong relationship among TCP traffic delay, throughput and ONU energy consumption under different sleep interval lengths. Moreover, we reveal that under high TCP traffic, both FSI and ESID will end up showing similar delay, energy and throughput performance. Our findings also show that doze mode can offer better TCP throughput and delay performance at the price of consuming more energy than cyclic sleep mode. In addition, our results provide a glimpse on understanding at what point doze mode becomes futile in improving energy saving of an ONU under TCP traffic. Furthermore, in this paper, we highlight important research issues that should be studied in future research to maximize energy saving in TDM-PONs while meeting traffic Quality of Service requirements.

  8. Tethering of Epidermal Growth Factor (EGF) to Beta Tricalcium Phosphate (βTCP) via Fusion to a High Affinity, Multimeric βTCP-Binding Peptide: Effects on Human Multipotent Stromal Cells/Connective Tissue Progenitors.

    Science.gov (United States)

    Alvarez, Luis M; Rivera, Jaime J; Stockdale, Linda; Saini, Sunil; Lee, Richard T; Griffith, Linda G

    2015-01-01

    Transplantation of freshly-aspirated autologous bone marrow, together with a scaffold, is a promising clinical alternative to harvest and transplantation of autologous bone for treatment of large defects. However, survival proliferation, and osteogenic differentiation of the marrow-resident stem and progenitor cells with osteogenic potential can be limited in large defects by the inflammatory microenvironment. Previous studies using EGF tethered to synthetic polymer substrates have demonstrated that surface-tethered EGF can protect human bone marrow-derived osteogenic stem and progenitor cells from pro-death inflammatory cues and enhance their proliferation without detriment to subsequent osteogenic differentiation. The objective of this study was to identify a facile means of tethering EGF to clinically-relevant βTCP scaffolds and to demonstrate the bioactivity of EGF tethered to βTCP using stimulation of the proliferative response of human bone-marrow derived mesenchymal stem cells (hBMSC) as a phenotypic metric. We used a phage display library and panned against βTCP and composites of βTCP with a degradable polyester biomaterial, together with orthogonal blocking schemes, to identify a 12-amino acid consensus binding peptide sequence, LLADTTHHRPWT, with high affinity for βTCP. When a single copy of this βTCP-binding peptide sequence was fused to EGF via a flexible peptide tether domain and expressed recombinantly in E. coli together with a maltose-binding domain to aid purification, the resulting fusion protein exhibited modest affinity for βTCP. However, a fusion protein containing a linear concatamer containing 10 repeats of the binding motif the resulting fusion protein showed high affinity stable binding to βTCP, with only 25% of the protein released after 7 days at 37oC. The fusion protein was bioactive, as assessed by its abilities to activate kinase signaling pathways downstream of the EGF receptor when presented in soluble form, and to enhance

  9. Tethering of Epidermal Growth Factor (EGF to Beta Tricalcium Phosphate (βTCP via Fusion to a High Affinity, Multimeric βTCP-Binding Peptide: Effects on Human Multipotent Stromal Cells/Connective Tissue Progenitors.

    Directory of Open Access Journals (Sweden)

    Luis M Alvarez

    Full Text Available Transplantation of freshly-aspirated autologous bone marrow, together with a scaffold, is a promising clinical alternative to harvest and transplantation of autologous bone for treatment of large defects. However, survival proliferation, and osteogenic differentiation of the marrow-resident stem and progenitor cells with osteogenic potential can be limited in large defects by the inflammatory microenvironment. Previous studies using EGF tethered to synthetic polymer substrates have demonstrated that surface-tethered EGF can protect human bone marrow-derived osteogenic stem and progenitor cells from pro-death inflammatory cues and enhance their proliferation without detriment to subsequent osteogenic differentiation. The objective of this study was to identify a facile means of tethering EGF to clinically-relevant βTCP scaffolds and to demonstrate the bioactivity of EGF tethered to βTCP using stimulation of the proliferative response of human bone-marrow derived mesenchymal stem cells (hBMSC as a phenotypic metric. We used a phage display library and panned against βTCP and composites of βTCP with a degradable polyester biomaterial, together with orthogonal blocking schemes, to identify a 12-amino acid consensus binding peptide sequence, LLADTTHHRPWT, with high affinity for βTCP. When a single copy of this βTCP-binding peptide sequence was fused to EGF via a flexible peptide tether domain and expressed recombinantly in E. coli together with a maltose-binding domain to aid purification, the resulting fusion protein exhibited modest affinity for βTCP. However, a fusion protein containing a linear concatamer containing 10 repeats of the binding motif the resulting fusion protein showed high affinity stable binding to βTCP, with only 25% of the protein released after 7 days at 37oC. The fusion protein was bioactive, as assessed by its abilities to activate kinase signaling pathways downstream of the EGF receptor when presented in soluble form

  10. TCP/IP协议下网络编程技术及其实现%Network Programming Technique and Implementation in TCP/IP Protocol

    Institute of Scientific and Technical Information of China (English)

    周炎涛; 李立明

    2002-01-01

    建立在传输层协议上的抽象数据结构socket作为网络中数据交换的排队点,是TCP/IP网络最为通用的API.文章在介绍TCP协议客户端和服务器端进程通信流程和具体实现的基础上,以Delphi环境为编程语言说明了在Windows下使用socket进行网络编程的方法和特点.基于事务处理的socket网络编程技术可应用在分布式系统进程通信中,是Internet上进行应用开发最为通用的API.

  11. Hypo-fractionated treatment in radiotherapy: radio-biological models Tcp and NTCP; Tratamiento hipofraccionado en radioterapia: modelos radiobiologicos TCP y NTCP

    Energy Technology Data Exchange (ETDEWEB)

    Astudillo V, A. J.; Mitsoura, E. [Universidad Autonoma del Estado de Mexico, Facultad de Medicina, Paseo Tollocan s/n, 50180 Toluca, Estado de Mexico (Mexico); Paredes G, L. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Resendiz G, G., E-mail: lydia.paredes@inin.gob.mx [Hospital Medica Sur, Departamento de Radioterapia, Puente de Piedra 150, Col. Toriello Guerra, 14050 Mexico D. F. (Mexico)

    2014-08-15

    At the present time the breast cancer in Mexico has the first place of incidence of the malignant neoplasia s in the women, and represents 11.34% of all the cancer cases. On the other hand, the treatments for cancer by means of ionizing radiations have been dominated under the approaches of the medical radio-oncologists which have been based on test and error by many years. The radio-biological models, as the Tcp, NTCP and dosimetric variables, for their clinical application in the conventional radiotherapy with hypo-fractionation have as purpose predicting personalized treatment plans that they present most probability of tumor control and minor probability of late reactions, becoming this way support tools in the decisions taking for the patient treatments planning of Medical Physicists and Radio-oncologists. (Author)

  12. Communication power supply monitoring system based on TCP/IP protocol%基于TCP/IP协议的通信电源监控系统

    Institute of Scientific and Technical Information of China (English)

    杨洪军

    2016-01-01

    在讨论通信基站动环监控系统的总体设计、硬件组成、软件设计的基础上,以运营商的小流量卡为通信载体,设计了通信基站内电源、空调等设备的遥测、遥信和遥控等三遥功能.该监控系统采用三级分层结构,分别为前置监控单元(SM)、局站监控中心(SU)和区域监控中心(SC),SU和SC之间采用TCP/IP协议进行通信.为了提高通信的及时性,对协议栈进行了改进.

  13. TCP/UDP下一种网络透明传输服务编程接口实现方法%Implementation of a Service API on Transparent Network Communication Programming Based on TCP/UDP

    Institute of Scientific and Technical Information of China (English)

    何波玲; 隋菱歌

    2011-01-01

    To write network communication code based on TCP/UDP,you must understand some network communication concepts such as IP address,port,socket,TCP/UDP protocols etc.This paper implemented a service API(Application Programming Interface) that encapsulate all network communication concepts and make TCP programming and UDP programming with the same mode.The results show that the API can make network communication programming very easily with no network concepts and supposes real-time and reliable communication and multi-NIC(Network Interface Card) in same host.%使用在TCP/UDP协议进行网络通信,会涉及IP地址、端口号、套接字、TCP/UDP协议等网络通信概念,而且TCP传输和UDP传输的编程模式是不同的,对网络通信概念进行了封装,实现了一个网络通信透明传输服务系统,且TCP传输和UDP传输具有相同的编程模式.使用表明,用户无需了解网络通信概念,即可使用该系统进行通信编程,使用极为方便,实现网络通信的实时传输、可靠传输和同一主机的多网卡支持.

  14. 基于μC/OS-Ⅱ系统的TCP/IP协议栈实现%Realization of TCP/IP Protocol Stack Based on μC/OS- Ⅱ System

    Institute of Scientific and Technical Information of China (English)

    董峰; 李小明

    2011-01-01

    The introduction of real-time operating system in embedded TCP/IP protocol stack, to support embedded devices access the network, becomes an important research direction in the field of embedded. This article introduced the structure of the open source real-time operating system μC/OS- Ⅱ and the method of transplant in STM32, studied the structure and work processes of the embedded TCP/IP protocol stack, described the concrete realization in μC/OS-II system of the three most important protocols ARP and IP and TCP.%在嵌入式实时操作系统中引入TCP/IP协议栈,以支持嵌入式设备接入网络,成为嵌入式领域重要的研究方向.介绍了开源的μC/OS-Ⅱ实时操作系统结构和在STM32上的移植方法,研究了嵌入式TCP/IP协议栈结构及工作流程,并详细描述协议栈中ARP、IP和TCP这3种最重要协议在μC/OS-Ⅱ系统上的具体实现.

  15. Active-TCP congestion control approach%一种主动TCP拥塞控制方案

    Institute of Scientific and Technical Information of China (English)

    何利; 鲜永菊

    2009-01-01

    基于广泛使用的TCP版本TCP Reno,提出了一种主动TCP拥塞控制方案,命名Active-TCP.在沿用传统的被动拥塞控制方式的同时,Active-TCP添加了主动拥塞控制方式,即在满足给定条件下,Active-TCP可主动降低拥塞窗口,而此时网络并未真正发生拥塞.仿真分析了Active-TCP性能,结果表明,与TCP Reno相比,使用Active-TCP可改善吞吐量,降低报文重传率;Active-TCP也能与TCP Reno友好共存,公平竞争网络资源.另外,Active-TCP可由TCP Reno发送方作较小修改得到,因此Active-TCP容易实现,所增加的额外开销较少.

  16. Genome-wide Identification of TCP Family Transcription Factors from Populus euphratica and Their Involvement in Leaf Shape Regulation.

    Science.gov (United States)

    Ma, Xiaodong; Ma, Jianchao; Fan, Di; Li, Chaofeng; Jiang, Yuanzhong; Luo, Keming

    2016-09-08

    Higher plants have been shown to experience a juvenile vegetative phase, an adult vegetative phase, and a reproductive phase during its postembryonic development and distinct lateral organ morphologies have been observed at the different development stages. Populus euphratica, commonly known as a desert poplar, has developed heteromorphic leaves during its development. The TCP family genes encode a group of plant-specific transcription factors involved in several aspects of plant development. In particular, TCPs have been shown to influence leaf size and shape in many herbaceous plants. However, whether these functions are conserved in woody plants remains unknown. In the present study, we carried out genome-wide identification of TCP genes in P. euphratica and P. trichocarpa, and 33 and 36 genes encoding putative TCP proteins were found, respectively. Phylogenetic analysis of the poplar TCPs together with Arabidopsis TCPs indicated a biased expansion of the TCP gene family via segmental duplications. In addition, our results have also shown a correlation between different expression patterns of several P. euphratica TCP genes and leaf shape variations, indicating their involvement in the regulation of leaf shape development.

  17. Structure, mechanical property and corrosion behaviors of (HA+β-TCP)/Mg-5Sn composite with interpenetrating networks.

    Science.gov (United States)

    Wang, X; Li, J T; Xie, M Y; Qu, L J; Zhang, P; Li, X L

    2015-11-01

    In this paper, a novel (Hydroxyapatite+β-tricalcium phosphate)/Mg-5Sn ((HA+β-TCP)/Mg-5Sn) composite with interpenetrating networks was fabricated by infiltrating Mg-5Sn alloy into porous HA+β-TCP using suction casting technique. The structure, mechanical property and corrosion behaviors of the composite have been evaluated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), mechanical testing, electrochemical and immersion test. It is shown that the molten Mg-5Sn alloy has infiltrated not only into the pores but also into the struts of the HA+β-TCP scaffold to forming a compact composite. The microstructure observation also shows that the Mg alloy contacts to the HA+β-TCP closely, and no reaction layer can be found between Mg-5Sn alloy and scaffold. The ultimate compressive strength of the composite is as high as 176MPa, which is about four fifths of the strength of the Mg-5Sn bulk alloy. The electrochemical and immersion tests indicate that the corrosion resistance of the composite is better than that of the Mg-5Sn bulk alloy. The corrosion products on the composite surface are mainly Mg(OH)2, Ca3(PO4)2 and HA. Appropriate mechanical and corrosion properties of the (HA+β-TCP)/Mg-5Sn composite indicate its possibility for new bone tissue implant materials.

  18. Effect of Water-Glass Coating on HA and HA-TCP Samples for MSCs Adhesion, Proliferation, and Differentiation

    Directory of Open Access Journals (Sweden)

    Indu Bajpai

    2016-01-01

    Full Text Available Ca-P and silicon based materials have become very popular as bone tissue engineering materials. In this study, water-glass (also known as sodium silicate glass was coated on sintered hydroxyapatite (HA and HA-TCP (TCP stands for tricalcium phosphate samples and subsequently heat-treated at 600°C for 2 hrs. X-rays diffraction showed the presence of β- and α-TCP phases along with HA in the HA-TCP samples. Samples without coating, with water-glass coating, and heat-treated after water-glass coating were used to observe the adhesion and proliferation response of bone marrow derived-mesenchymal stem cells (MSCs. Cell culture was carried out for 4 hrs, 1 day, and 7 days. Interestingly, all samples showed similar response for cell adhesion and proliferation up to 7-day culture but fibronectin, E-cadherin, and osteogenic differentiation related genes (osteocalcin and osteopontin were significantly induced in heat-treated water-glass coated HA-TCP samples. A water-glass coating on Ca-P samples was not found to influence the cell proliferation response significantly but activated some extracellular matrix genes and induced osteogenic differentiation in the MSCs.

  19. Potential implications on TCP for external beam prostate cancer treatment when considering the bystander effect in partial exposure scenarios.

    Science.gov (United States)

    Balderson, Michael John; Kirkby, Charles

    2014-02-01

    This work investigated the potential implications on tumour control probability (TCP) for external beam prostate cancer treatment when considering the bystander effect in partial exposure scenarios. The biological response of a prostate cancer target volume under conditions where a sub-volume of the target volume was not directly irradiated was modelled in terms of surviving fraction (SF) and Poisson-based TCP. A direct comparison was made between the linear-quadratic (LQ) response model, and a response model that incorporates bystander effects as derived from published in vitro data by McMahon et al. in 2012 and 2013. Scenarios of random and systematic misses were considered. Our results suggested the potential for the bystander effect to deviate from LQ predictions when even very small (bystander model predicts a 3% and 1% improvement in tumour control compared to that predicted by an LQ model when only 90% and 95% of the prostate cells randomly receive the intended dose. Under conditions of systematic miss, if even a small portion of the target volume is not directly exposed, the LQ model predicts a TCP approaching zero, whereas the bystander model suggests TCP will improve starting at exposed volumes of around 85%. The bystander model, when applied to clinically relevant scenarios, demonstrates the potential to deviate from the TCP predictions of the common local LQ model when sub-volumes of a target volume are randomly or systematically missed over a course of fractionated radiation therapy.

  20. SET: Session Layer-Assisted Efficient TCP Management Architecture for 6LoWPAN with Multiple Gateways

    Directory of Open Access Journals (Sweden)

    Akbar AliHammad

    2010-01-01

    Full Text Available 6LoWPAN (IPv6 based Low-Power Personal Area Network is a protocol specification that facilitates communication of IPv6 packets on top of IEEE 802.15.4 so that Internet and wireless sensor networks can be inter-connected. This interconnection is especially required in commercial and enterprise applications of sensor networks where reliable and timely data transfers such as multiple code updates are needed from Internet nodes to sensor nodes. For this type of inbound traffic which is mostly bulk, TCP as transport layer protocol is essential, resulting in end-to-end TCP session through a default gateway. In this scenario, a single gateway tends to become the bottleneck because of non-uniform connectivity to all the sensor nodes besides being vulnerable to buffer overflow. We propose SET; a management architecture for multiple split-TCP sessions across a number of serving gateways. SET implements striping and multiple TCP session management through a shim at session layer. Through analytical modeling and ns2 simulations, we show that our proposed architecture optimizes communication for ingress bulk data transfer while providing associated load balancing services. We conclude that multiple split-TCP sessions managed in parallel across a number of gateways result in reduced latency for bulk data transfer and provide robustness against gateway failures.