“拒绝”与“回绝”语义对比分析

以现代汉语同义词“拒绝”与“回绝”为研究对象,运用语义特征分析法和三个平面语法理论,从动作行为、行为主体对象、行为连带对象三个方面,对二者进行全面系统的语义对比分析,揭示其中的同与异。为今后的对外汉语教学提供有益的参考,帮助留学生掌握其基本用法,减少使用偏误。

Effect of CXCR3/HO-1 genes modified bone marrow mesenchymal stem cells on small bowel transplant rejection

AIM To investigate whether bone marrow mesenchymal stem cells (BMMSCs) modified with the HO-1 and CXCR3 genes can augment the inhibitory effect of BMMSCs on small bowel transplant rejection. METHODS Lewis rat BMMSCs were cultured in vitro. Third-passage BMMSCs were transduced with the CXCR3 / HO-1 genes or the HO-1 gene alone. The rats were divided into six groups and rats in the experimental group were pretreated with BMMSCs 7 d prior to small bowel transplant. Six time points (instant, 1 d, 3 d, 7 d, 10 d, and 14 d) (n = 6) were chosen for each group. Hematoxylin-eosin staining was used to observe pathologic rejection, while immunohistochemistry and Western blot were used to detect protein expression. Flow cytometry was used to detect T lymphocytes and enzyme linked immunosorbent assay was used to detect cytokines. RESULTS The median survival time of BMMSCs from the CXCR3/HO-1 modified group (53 d) was significantly longer than that of the HO-1 modified BMMSCs group (39 d), the BMMSCs group (26 d), and the NS group (control group) (16 d) (P < 0.05). Compared with BMMSCs from the HO-1 modified BMMSCs, BMMSCs, and NS groups, rejection of the small bowel in the CXCR3 / HO-1 modified group was significantly reduced, while the weight of transplant recipients was also significantly decreased (P < 0.05). Furthermore, IL-2, IL-6, IL-17, IFN-gamma, and TNF-alpha levels were significantly decreased and the levels of IL-10 and TGF-beta were significantly increased (P < 0.05). CONCLUSION BMMSCs modified with the CXCR3 and HO-1 genes can abrogate the rejection of transplanted small bowel more effectively and significantly increase the survival time of rats that receive a small bowel transplant.

A Novel Distributed LDoS Attack Scheme against Internet Routing

LDoS （Low-rate Denial of Service） attack, exploiting the flaws in the congestion avoidance mechanism of TCP protocol,is periodic, stealthy, and with high efficiency. Since BGP uses TCP as a transport protocol, it is subject to LDoS attacks as well. LDoS attacks can cause table reset, route flapping of BGP protocol. A deliberately constructed distributed low-rate DOS attacks can even generate surge of updates throughout the Internet. In this paper, we investigate the promotion of attack efficiency of this novel attack, and then propose an attack model to simulate the LDoS attack. Experiments prove that this attack model can exponentially lower the attack costs and improve the attack effect.

Low-Rate DoS Attack Flows Filtering Based on Frequency Spectral Analysis

In frequency domain,the power spectrum of Low-rate denial of service(LDoS) attacks is totally spread into the spectrum of normal traffic.It is a challenging task to detect and filter LDoS attack flows from the normal traffic.Based on the analysis of LDoS attack flows and legitimate TCP traffic in time and frequency domains,the periodicity of the TCP traffic and LDoS attack flows is explored to facilitate the research of network traffic processing.Hence,an approach of LDoS attack flow filtering based on frequency spectrum analysis is proposed.In this approach,the TCP traffic and LDoS attack flows are transformed from the time domain into the frequency domain.Then the round-trip time(RTT) is estimated by using frequency domain search method.Analysis of amplitude spectrum shows that TCP traffic energy is mainly concentrated on the points of n/RTT.Therefore,a comb filter using infinite impulse response(IIR) filter is designed to filter out the LDoS attack flows in frequency domain,while most legitimate TCP traffic energy at the points of n/RTT are pass through.Experimental results show that the maximum pass rate for legitimate TCP traffic reaches 92.55%,while the maximum filtration rate of LDoS attack flows reaches 81.36%.The proposed approach can effectively filter the LDoS attack flows while less impact on the legitimate TCP traffic.

Sinusoidal endotheliitis as a histological parameter for diagnosing acute liver allograft rejection

AIMTo investigated the feasibility of using sinusoidal endotheliitis (SE) as a histological marker for liver allograft rejection.METHODSWe compared the histological features of 88 liver allograft biopsies with acute cellular rejection (ACR) and 59 cases with no evidence of ACR. SE was scored as: (1) focal linear lifting up of the endothelial cells by lymphocytes with no obvious damage to adjacent hepatocytes; (2) focal disruption of the endothelial lining by a cluster of subendothelial lymphocytes (a group of &#x0003e; 3 lymphocytes); and (3) severe confluent endotheliitis with hemorrhage and adjacent hepatocyte loss.RESULTSThe sensitivity and specificity of SE was 81% and 85%, respectively. Using SE as the only parameter, the positive predictive value for ACR (PPV) was 0.89, whereas the negative predictive value for ACR (NPV) was 0.75. The correlation between RAI and SE was moderate (R = 0.44, P &#x0003c; 0.001) (Figure 3A), whereas it became strong (R = 0.65, P &#x0003c; 0.001) when correlating SE with the venous endotheliitis activity index only.CONCLUSIONOur data suggest that SE scoring could be a reliable and reproducible supplemental parameter to the existing Banff schema for diagnosing acute liver allograft rejection.

A Survey of Security Issues in Cognitive Radio Networks

In the last decade,cognitive radio(CR) has emerged as a major next generation wireless networking technology,which is the most promising candidate solution to solve the spectrum scarcity and improve the spectrum utilization.However,there exist enormous challenges for the open and random access environment of CRNs,where the unlicensed secondary users(SUs) can use the channels that are not currently used by the licensed primary users(PUs) via spectrum-sensing technology.Because of this access method,some malicious users may access the cognitive network arbitrarily and launch some special attacks,such as primary user emulation attack,falsifying data or denial of service attack,which will cause serious damage to the cognitive radio network.In addition to the specifi c security threats of cognitive network,CRNs also face up to the conventional security threats,such as eavesdropping,tampering,imitation,forgery,and noncooperation etc..Hence,Cognitive radio networks have much more risks than traditional wireless networks with its special network model.In this paper,we considered the security threats from passive and active attacks.Firstly,the PHY layer security is presented in the view of passive attacks,and it is a compelling idea of using the physical properties of the radio channel to help provide secure wireless communications.Moreover,malicious user detection is introduced in the view of active attacks by means of the signal detection techniques to decrease the interference and the probabilities of false alarm and missed detection.Finally,we discuss the general countermeasures of security threats in three phases.In particular,we discuss the far reaching effect of defensive strategy against attacks in CRNs.

Pretransplantation fetal-maternal microchimerism in pediatric liver transplantation from mother

AIM To investigate the rates of pretransplantation fetalmaternal microchimerism(MC) and its effect on rejection in children receiving maternal liver grafts. METHODS DNA or blood samples before liver transplantation(LT) were available in 45 pediatric patients and their mothers. The presence of pretransplantation MC to non-inherited maternal antigens(NIMAs)(NIMA-MC) in the peripheral blood was tested using nested PCRsingle-strand conformation polymorphism analysis for the human leukocyte antigen(HLA)-DRB1 alleles. NIMA-MC was successfully evaluated in 26 of the 45 children. Among these 45 pediatric LT recipients,23 children(51.1%) received transplants from maternal donors and the other 22 from non-maternal donors.RESULTS Among these 26 children,pretransplantation NIMAMC was detected in 23.1%(n = 6),6.1(range,0.8-14) years after birth. Among the children with a maternal donor,the rate of biopsy-proven cellular rejection(BPCR) was 0% in patients with NIMA-MC positivity(0/3) and those with HLA-DR identity with the mother(0/4),but it was 50% in those with NIMA-MC negativity(5/10). Patients with NIMA-MC positivity or HLA-DR identity with the mother showed significantly lower BPCR rate compared with NIMA-MC-negative patients(0% vs 50%,P = 0.04). NIMA-MC-positive patients tended to show lower BPCR rate compared with NIMAMC-negative patients(P = 0.23). CONCLUSION The presence of pretransplantation NIMA-MC or HLADR identity with the mother could be associated with BPCR-free survival in pediatric recipients of LT from maternal donors.

Optimal design of nanofiltration system for surface water treatment

Both reverse osmosis(RO) and nanofiltration(NF) membranes have been increasingly used for water purification and desalination. However, the salt rejection of NF membranes is quite different from that of RO membranes,which makes a significant distinction in their process designs. This work started from the performance investigation of a single NF membrane element and then focused on the process design of the NF system for surface water treatment. In experimental tests, it was found that the observed rejection of the NF element becomes nearly constant when the concentrate flow is large enough, while the membrane flux of the NF element is quite stable regardless of the water flow across the membrane surface. These findings can be used to instruct the process design of the NF system for surface water treatment. In process design, a two-stage arrangement is sufficient for the NF system to reach the highest water recovery, while the RO system requires a three-stage arrangement.

A Router Based Packet Filtering Scheme for Defending Against DoS Attacks

The filter-based reactive packet filtering is a key technology in attack traffic filtering for defending against the Denial-of- Service （DOS） attacks. Two kinds of relevant schemes have been proposed as victim- end filtering and source-end filtering. The first scheme prevents attack traffic from reaching the victim, but causes the huge loss of legitimate flows due to the scarce filters （termed as collateral damages）; the other extreme scheme can obtain the sufficient filters, but severely degrades the network transmission performance due to the abused filtering routers. In this paper, we propose a router based packet filtering scheme, which provides relatively more filters while reducing the quantity of filtering touters. We implement this scheme on the emulated DoS scenarios based on the synthetic and real-world Internet topologies. Our evaluation results show that compared to the previous work, our scheme just uses 20% of its filtering routers, but only increasing less than 15 percent of its collateral damage.

SAFE:a Scalable Filter-Based Packet Filtering Scheme

Recently, attacks have become Denial-of-Service （DOS） the mainstream threat to the internet service availability. The filter-based packet filtering is a key technology to defend against such attacks. Relying on the filtering location, the proposed schemes can be grouped into Victim-end Filtering and Source-end Filtering. The first scheme uses a single filtering router to block the attack flows near the victim, but does not take the factor that the filters are scarce resource into account, which causes the huge loss of legitimate flows; considering each router could contribute a few filters, the other extreme scheme pushes the filtering location back into each attack source so as to obtain ample filters, but this may incur the severe network transmission delay due to the abused filtering routers. Therefore, in this paper, we propose a scalable filter-based packet filtering scheme to balance the number of filtering routers and the available filters. Through emulating DoS scenarios based on the synthetic and real-world Intemet topologies and further implementing the various filter-based packet filtering schemes on them, the results show that our scheme just uses fewer filtering routers to cut off all attack flows while minimizing the loss of legitimate flows.

Deterministic Quantum Secure Direct Communication with Dense Coding and Continuous Variable Operations

We propose a deterministic quantum secure direct two check photon sequences are used to check the securities of the communication protocol by using dense coding. The channels between the message sender and the receiver. The continuous variable operations instead of the usual discrete unitary operations are performed on the travel photons so that the security of the present protocol can be enhanced. Therefore some specific attacks such as denial-of-service attack, intercept-measure-resend attack and invisible photon attack can be prevented in ideal quantum channel. In addition, the scheme is still secure in noise channel. Furthurmore, this protocol has the advantage of high capacity and can be realized in the experiment.

Modeling and Simulation of Low Rate of Denial of Service Attacks

The low-rate denial of service attack is more applicable to the network in recent years as a means of attack, which is different from the traditional field type DoS attacks at the network end system or network using adaptive mechanisms exist loopholes flow through the low-rate periodic attacks on the implementation of high-efficiency attacked by an intruder and not be found, resulting in loss of user data or a computer deadlock. LDos attack since there has been extensive attention of researchers, the attack signature analysis and detection methods to prevent network security have become an important research topic. Some have been proposed for the current attacks were classified LDoS describe and model, and then in NS-2 platform for experimental verification, and then LDoS attack detection to prevent difficulties are discussed and summarized for the future such attacks detection method research work to provide a reference.

A Study on the Architectural Application of Aerogel

As the building energy saving is more and more important, high-performing insulation like aerogel will be required in buildings to improve their thermal environment and to save building energy. This study conducted the literature survey on the aerogel blanket and presents the architectural application considering its high-insulating property. If aerogel is applied to a building as an envelope insulation, its thickness could be reduced to as half as that of existing insulation such as polystyrene foam board or glassfiber. Currently, aerogel is largely used as a thermal breaker in thermal bridges in buildings. It is still too expensive to be used as a main insulation of whole building envelopes. Thanks to the advantages of aerogel blanket such as low thermal conductivity, broad temperature range for use, excellent water repellent property and fire resistance, easiness of moving and applying, it has much possibility in the respect of its building application.

ON THE CLASSIFICATION OF SPEECH ACT REFUSALS IN CHINESE:EVIDENCE AND MOTIVATING FACTORS

This paper examines the phenomenon of sociocultural transfer and its motivating factors within the realization patterns of speech act refusal by Chinese EFL learners. EFL refusal data were collected using a written data collection test (DCT), which was designed and then followed by semi-structured interviews. Using semantic formulas as units of analysis, EFL refusal responses were compared with similar data elicited from native speakers of English. The results show two areas in which sociocultural transfer is existent in EFL learners' speech: options of selecting semantic formulas and content of semantic formulas. Each was found to reflect cultural values transferred from Chinese to English. Furthermore, based on the interview data, it was found that learners' social system and political factors, traditional socio-psychological ideology and economy possibly motivate sociocultural transfer.

Th17 promotes acute rejection following liver transplantation in rats

T help cell 17(Th17) ,recently identified as a new subset of CD4+T cells,has been implicated in autoimmune diseases,tumor immunity,and transplant rejection.To investigate the role of Th17 in acute hepatic rejection,a rat model of allogeneic liver transplantation(Dark Agouti(DA) to Brown Norway(BN) ) was established and isogeneic liver transplantation(BN to BN) was used as controls in the study.The expression of Th17-related cytokines in the liver and peripheral blood was determined by immunohistochemistry,flow cytometry,enzyme-linked immunosorbent assay(ELISA) ,or real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR) .Strong expression of interleukin-17A(IL-17A) ,IL-6,transforming growth factor-β(TGF-β) ,IL-8,and myeloperoxidase(MPO) was observed in liver allografts.The ratios of Th17 to CD4 + lymphocytes in the liver and peripheral blood were dramatically increased in the allograft group compared with the control(P<0.01) .Secreted IL-17 and IL-6 in liver homogenate and serum were significantly elevated in the allograft group,while secreted TGF-βwas increased in liver homogenate and decreased in serum compared with the control(P<0.01) .The messenger RNA(mRNA) levels of IL-17,IL-21,and IL-23 were enhanced in the allografts compared with the control(P<0.01) .Correlation analysis showed significant correlations between IL-17 and IL-6 and TGF-βand between IL-17 and IL-21 and IL-23.The present study demonstrates that Th17 plays a role in promoting rat liver allograft rejection.

Tuning of Sampled-Data ADRC for Nonlinear Uncertain Systems

This paper concerns with the parameters tuning of active disturbance rejection control(ADRC) for a class of nonlinear systems with sampling rate not fast enough. The theoretical results show the quantitative relationship between the sampling rate, the parameters of ADRC, the size of uncertainties in system and the properties of the closed-loop system. Furthermore, the capability of the sampled-data ADRC under given sampling rate is quantitatively discussed.

ON-LINE SCHEDULING WITH REJECTION ON IDENTICAL PARALLEL MACHINES

In this paper, we consider the on-line scheduling of unit time jobs with rejection on rn identical parallel machines. The objective is to minimize the total completion time of the accepted jobs plus the total penalty of the rejected jobs. We give an on-line algorithm for the problem with competitive ratio 1/2 （2 ＋√3） ≈ 1.86602.

High-efficiency quantum steganography based on the tensor product of Bell states

In this paper,we first propose a hidden rule among the secure message,the initial tensor product of two Bell states and the final tensor product when respectively applying local unitary transformations to the first particle of the two initial Bell states,and then present a high-efficiency quantum steganography protocol under the control of the hidden rule.In the proposed quantum steganography scheme,a hidden channel is established to transfer a secret message within any quantum secure direct communication(QSDC) scheme that is based on 2-level quantum states and unitary transformations.The secret message hiding/unhiding process is linked with the QSDC process only by unitary transformations.To accurately describe the capacity of a steganography scheme,a quantitative measure,named embedding efficiency,is introduced in this paper.The performance analysis shows that the proposed steganography scheme achieves a high efficiency as well as a good imperceptibility.Moreover,it is shown that this scheme can resist all serious attacks including the intercept-resend attack,measurement-resend attack,auxiliary particle attack and even the Denial of Service attack.To improve the efficiency of the proposed scheme,the hidden rule is extended based on the tensor product of multiple Bell states.