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Wi-Fi device authentication is crucial for defending against impersonation attacks and information forgery attacks. Most of the existing authentication technologies rely on complex cryptographic algorithms. However, they cannot be supported well on the devices with limited hardware resources. A fine-grained device authentication technology based on channel state information (CSI) provides a noncryptographic method, which uses the CSI fingerprints for authentication since CSI can uniquely identify the devices. But long-term authentication based on CSI fingerprints is a challenging work. First, the CSI fingerprints are environment-sensitive, which means that the local authenticator should be updated to adapt to the changing channel state. Second, the local authenticator trained with old CSI fingerprints is outdated when users reconnect to the network after being offline for a long time, thus, it needs to be retrained in the access phase with new fingerprints. To tackle these challenges, we propose a CSI-based enhancing Wi-Fi device authentication protocol and an authentication framework. The protocol helps to collect new CSI fingerprints for authenticator’s training in access phase and performs the fingerprints’ dispersion analysis for authentication. In the association phase, it provides packet-level authentication and updates the authenticator with valid CSI fingerprints. The authenticator consists of an ensemble of small-scale autoencoders, which has high enough time efficiency for packet-level authentication and authenticator’s update. Experiments show that the accuracy of the framework is up to 98.7%, and the authenticator updating method can help the framework maintains high accuracy.

Background The influence of positive microscopic margin (R1) resection on the prognosis of gastrointestinal stromal tumors (GISTs) is controversial. Tumor rupture is significantly associated with the occurrence of R1 resection and may be a confounder of R1 resection in GISTs. The present meta-analysis evaluated the real influence of R1 resection on the prognosis of GISTs by excluding the confounding effect of tumor rupture. Methods The PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases were searched. Studies that compared R1 with negative microscopic margin (R0) resection in GIST patients and reported the time-to-event data of recurrence-free survival (RFS) or disease-free survival (DFS) were eligible for inclusion. The quality of the observational studies was assessed using the Newcastle–Ottawa scale. Results Of the 4896 records screened, 23 retrospective studies with 6248 participants were selected. In the overall analysis, R1 resection resulted in a significantly shorter RFS/DFS than R0 resection for GISTs (HR = 1.80, 95% CI = 1.54–2.10, P Conclusions This meta-analysis shows that R1 resection did not influence the survival outcome of GISTs. Reresection may not be necessary when positive microscopic margins exist. This analysis could provide high-quality evidence for the development of guidelines.

The development and supporting technologies of high-strain line pipe steel and pipes used for oil and gas pipeline projects in special geological environments (such as earthquake zone, landslide zone, mine goaf and subsidence zone) is one of the international research hotspots, and it is also a major problem that China's major oil and gas pipeline projects have to solve. Focusing on a series of key technical difficulties in the research & development and application of high-strain line pipe steel and pipes, a number of theoretical and technological innovations have been achieved after more than ten years of joint researches. And the main achievements are as follows. First, the method of applying many different parameters (e.g. stress ratio, yield to tensile ratio and uniform elongation (UEL)) to comprehensively characterize and evaluate the deformation behavior of steel pipes is proposed, and a technical index system and standard for the new products of X70HD/X80HD high-strain line pipe steel and pipes are established. Second, a complete set of X70HD/X80HD steel plate manufacturing technology is researched and developed, and the high-strain steel plate with the properties of low yield to tensile ratio, high uniform elongation, high stress ratio and high strength and toughness is worked out. Third, the X70HD/X80HD JCOE and UOE high-strain longitudinal submerged arc welded pipe manufacturing technology is researched and developed, reasonable performance matching between a steel pipe and a welding seam is realized, and the performance deterioration in the process of forming, welding, diameter-expending and thermal coating is solved. Fourth, a full-scale test device of steel pipe internal pressure + bending large deformation is independently developed, and the physical simulation based steel pipe deformation test technology is formed. X70HD/X80HD high-strain line pipe steel and pipes have been applied in the West to East Gas Pipeline, the China–Myanmar Pipeline and other major gas pipeline projects in the large scale, and their application effects are remarkable. To satisfy the new needs of pipeline construction and long-term safe operation under complex geological conditions, some suggestions were put forwarded, such as developing new methods of strain-based pipeline design, and researching and developing or improving the supporting technologies suitable for the higher matching requirements of girth weld, such as welding methods, welding materials, welding processes, and girth weld performance quality and defect control requirements.

Background The purpose of the study was to evaluate the association between microfibrillar collagen hemostat and anastomotic leakage after anterior resection. Method Between March 2015 and December 2019, a total of 203 consecutive rectal cancer patients who underwent elective anterior resection were included. Patient parameters were analyzed. The relevant risk factors were identified by univariate and multivariate analysis. Propensity score matching was performed to reduce the selection bias. Results In total, 26 (12.8%) of the 203 study patients developed clinical anastomotic leakage. The length of hospital stay was significantly prolonged by anastomotic leakage. In univariate analysis and multivariate analysis, male sex, low tumor location, and intraoperative application of microfibrillar collagen hemostat significantly increased the risk of anastomotic leakage. Furthermore, analysis after propensity score matching confirmed the independent role of microfibrillar collagen hemostat in anastomotic leakage. In addition, the median time of anastomotic leakage occurrence from the initial operation in patients with microfibrillar collagen hemostat was 9.00 days, which was significantly later than that in patients without microfibrillar collagen hemostat. Conclusion In addition to male sex and low tumor location, intraoperative application of microfibrillar collagen hemostat was demonstrated to be a significant risk factor for anastomotic leakage. This finding suggested that surgeons should be fully aware of this potential risk in anterior resection. Because of the limitation of retrospective study, however, randomized controlled trials are needed to confirm this association in the future.

As the most widely consumed beverage in the world, tea has various nutritional, economic, and global cultural values. With the development of the third-generation sequencing technology, several genome sequences of tea plants have been published. These genomic data have pivotal information that is of benefit to tea plant breeders and biologists in advancing tea plant improvement and the final quality of tea products. We hereby present the integrative online database, Tea Plant Genome Database (TeaPGDB; http://eplant.njau.edu.cn/tea ), which incorporates the published genome sequences of tea plants. The current release of TeaPGDB hosts published tea plant genome data with various online tools, including JBrowse, gene search, SSR search, BLAST. TeaPGDB also contains a download server, which provides access for the download of genome-related data and rich annotation files. TeaPGDB is committed to collecting, integrating, and annotating published tea plant genome data, providing data support for research on tea plant heredity, evolution, breeding for resistance, plant improvement, and facilitating the characterization of important traits or flavor related genes in the community. Compared with other tea plant databases, this database not only contains more complete genome data and gene annotation information, but also has a user-friendly interface for researchers in the field.

AIM Surgeons have concerns whether high ligation (HL) of the inferior mesenteric artery (IMA) increases the incidence of anastomotic leakage (AL). This meta-analysis aimed to evaluate the influence of HL of the IMA on AL compared with low ligation (LL). METHODS PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials and ClinicalTrials.gov databases were searched. Randomized controlled trial studies that compared HL with LL of the IMA in anterior resection for rectal cancer and reported AL outcomes were eligible for inclusion. The odds ratios and mean differences were analysed by a random-effects model. Trial sequential analysis was performed to minimize the risk of random errors. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to evaluate the quality of evidence for outcomes. RESULTS Of the 531 records screened, five randomized controlled trials with 779 patients were selected for analysis. The pooled incidence of AL was 12.1% (95% Cl 7.77-18.26) in the HL group and 9.7% (95% Cl 5.79-15.82) in the LL group (OR 1.20, 95% CI 0.77-1.87, P = 0.42). In trial sequential analysis, the cumulative Z-score curve exceeded the futility boundary, although the required information size of 1060 had not been reached. The quality of evidence was judged to be high according to the GRADE approach. CONCLUSIONS This meta-analysis shows that HL of the IMA does not increase the incidence of AL in anterior resection for rectal cancer.

Background: Approximately one-quarter of patients with early-stage hepatocellular carcinoma (HCC) suffer from tumor recurrence within the first year after hepatectomy. Identification of patients at high risk of recurrence and new therapeutic approaches are crucial to improve clinical outcome. This study aimed to assess the prognostic significance of miR-203 and Zinc finger E-box binding homeobox 1 (ZEB1) in early-stage HCC and explore the association between the expression of ZEB1 and miR-203 in HCC. Methods: Tissue microarray-based immunohistochemistry (IHC) and in situ hybridization (ISH) were performed to investigate ZEB1 and miR-203 expression in 73 patients with early-stage HCC and their correlation with clinicopathological features and prognosis of patients were analyzed. The prognostic value of the two factors was also measured by public KM plotter database. Quantitative reverse transcription PCR (qRT-PCR) assays were conducted to study the relationship between miR-203 and ZEB1. Transwell assays, Cell Counting Kit-8 (CCK-8) assays were performed to detect the roles of miR-203 in migration, invasion and proliferation of HCC cells. Results: We found low expression of miR-203 was associated significantly with tumor recurrence (P

Wi-Fi device authentication is crucial for defending against impersonation attacks and information forgery attacks. Most of the existing authentication technologies rely on complex cryptographic algorithms. However, they cannot be supported well on the devices with limited hardware resources. A fine-grained device authentication technology based on channel state information (CSI) provides a non-cryptographic method, which uses the fingerprint extracted from CSI for authentication since CSI can uniquely identify the device in a limited time. But maintaining a fingerprint database for fingerprint matching is a challenging work. Firstly, the fingerprints extracted from the CSI are time-sensitive, which means that the fingerprint database must be updated in real time; Secondly, the authentication device may collect false fingerprints under the attack of identity-based attackers, which means that the authenticity of the fingerprint used to update the database must be checked. In this paper, we propose an enhancing Wi-Fi device authentication protocol based on CSI to implement the fingerprint database update and the device authentication. We provide a viable method of database update and an authentication algorithm based on Local Outlier Factor (LOF). We also present a complete authentication process. In addition, we evaluate the performance of our CSI-based authentication algorithm and database updating method. The experiments showed that the accuracy of the authentication algorithm is up to 97.1% and our database updating method can help the system maintain high accuracy.

Anastomotic leakage (AL) is a severe complication of anterior resection for rectal cancer, with an incidence varying from 3.5% to 17.4%(1-3). Some studies (4, 5) consider high ligation (HL) of the inferior mesenteric artery (IMA) as a risk factor for AL.

International audience; A number of searchable encryption schemes have been widely proposed to solve the search problem in ciphertext domain. However, most existing searchable encryption schemes are vulnerable to keyword guessing attacks. During keyword guessing attacks, with the help of the cloud, an adversary will learn what keyword a given trapdoor is searching for, which leads to the disclosure of users’ privacy information. To address this issue, we propose SDKSE-KGA: a secure dynamic keyword searchable encryption scheme which resists keyword guessing attacks. SDKSE-KGA has constant-size indexes and trapdoors and supports functionalities such as dynamic updating of keywords and files. Formal proofs show that it is Trapdoor-IND-CKA and Index-IND-CKA secure in the standard model.

Vascular endothelial growth factor receptor 2 (VEGFR-2) and neuropilin-1 (NRP-1) are two prominent antiangiogenic targets. They are highly expressed on vascular endothelial cells and some tumor cells. Therefore, targeting VEGFR-2 and NRP-1 may be a potential antiangiogenic and antitumor strategy. A7R, a peptide with sequence of Ala-Thr-Trp-Leu-Pro-Pro-Arg that was found by phage display of peptide libraries, can preferentially target VEGFR-2 and NRP-1 and destroy the binding between vascular endothelial growth factor 165 (VEGF165) and VEGFR-2 or NRP-1. This peptide is a new potent inhibitor of tumor angiogenesis and a targeting ligand for cancer therapy. This review describes the discovery, function and mechanism of the action of A7R, and further introduces the applications of A7R in antitumor angiogenic treatments, tumor angiogenesis imaging and targeted drug delivery systems. In this review, strategies to deliver different drugs by A7R-modified liposomes and nanoparticles are highlighted. A7R, a new dual targeting ligand of VEGFR-2 and NRP-1, is expected to have efficient therapeutic or targeting roles in tumor drug delivery., Graphical abstract A7R, a new dual targeting ligand for vascular endothelial growth factor receptor 2 (VEGFR-2) and neuropilin-1(NRP-1), has been applied in the field of antiangiogenesis, tumor angiogenesis imaging and targeted drug delivery systems.Image, graphical abstract

Cloud computing has an significant impact on both academia and industry with its rapid development. by moving expensive operations like search to cloud, we are able to carry out complicated tasks efficiently. At the same time, cloud security has become a major concern. Malicious clouds are likely to sell privacy information for extra benefit. In order to protect privacy, data are encrypted before being uploaded to cloud. So how to handle encrypted data becomes a new challenge. In this paper we propose SDKSE: a secure dynamic keyword searchable encryption scheme for email systems under cloud computing environment. It is able to update files and keywords at any time. The indexes and the trapdoors generated in the scheme are constant size. In addition, we prove that it is adaptively Trapdoor-IND-CKA and Index-IND-CKA in the standard model.

The highly development of Internet and cloud computing technology makes it possible to share computing power, storage and data. Cloud computing makes users with limited computing resources be able to carry out large computational tasks with the help of cloud. but security is a major concern that hinders the widespread use of outsourcing computing. We focus on outsourcing large matrix multiplication in this paper. Firstly, we exploit Chinese Remainder Theorem(CRT) to construct a large matrix multiplication outsourcing protocol which is highly efficient in the malicious cloud model. Then formal security proof and extensive performance evaluation show that our protocol achieves a higher security level i.e., information-theoretic security for input privacy and adaptive chosen ciphertext attack (CCA2) security for output privacy). Compared with previous works, users in the proposed protocol are able to verify the results received from the cloud with tiny error rate.

Piezoelectric generators based on zinc oxide (ZnO) nanowires/nanorods require not only an aligned assembly morphology but also Schottky contacts between ZnO and electrodes to rectify the piezoelectric signals. Here we demonstrate that two-dimensional carbon nanotube (CNT) assembly films can serve as highly efficient electrode materials to meet these two requirements. The flexibility, porosity and pore size distribution, and intimate contact with ZnO of CNT films have advantages in controllable hydrothermal deposition to generate highly aligned ZnO nanorods with high crystallinity at a high density. Due to the Schottky characteristics between ZnO and CNT, aluminum and titanium are suggested to serve as the negative electrode of a piezoelectric energy supply, by using their ohmic contacts with ZnO. The three-layered piezoelectric generator outputs a signal of 50–60 mV by using bending deformations, one order of magnitude larger than the signal generated by fast pressing deformations. This study presents a method to design ZnO-based piezoelectric generators without using precious metals or rare earth elements.

How to identify whether T1-2 colorectal cancers have lymph nodes metastases pre-op or intra-op is a crucial problem in clinic. The purpose of this study was to evaluate the feasibility of using carbon nanoparticles to track lymph nodes metastases in T1-2 colorectal cancers.A multi-center study was performed between July 2012 and January 2014. Seventy-three patients with T1-2 colorectal cancer identified by pre-op endoscopic ultrasonography (EUS) were recruited. 1 ml carbon nanoparticles suspension was endoscopically injected into the submucosal layer at four points around the site of the primary tumor 1 day before surgery. Laparoscopic radical resection with lymphadenectomy was performed. Sentinel lymph nodes (SLNs) were defined as nodes that were black-dyed by carbon nanoparticles. Pathology confirmed whether lymph nodes have cancer metastases and the SLNs accuracy.SLNs were easily found under laparoscopy. The mean number of SLNs was 3 (range 1-5). All patients had SLNs lying alongside the mesenteric vessel or main arterial vessel. After pathological analysis, 2 patients (9.52%) had lymph node metastasis in 21 patients with EUS T1 cancers, and 10 patients (19.23%) had lymph node metastasis in 52 patients with EUS T2 cancers. In two T1 cases with lymph node metastasis, SLNs were positive with 100% accuracy. In ten T2 cases with lymph node metastasis, SLNs were positive in nine cases. In pathology, carbon nanoparticles were seen in lymphatic vessels, and lymphoid sinus and macrophages in negative SLNs. When SLNs were positive, carbon nanoparticles were seen around cancer cells in lymph nodes. The overall sensitivity, specificity, accuracy of SLNs in T1-2 colorectal cancers were 91.67, 100, 98.63%, respectively.We demonstrated the feasibility of using carbon nanoparticles to track lymph nodes metastases in T1-2 colorectal cancers. Carbon nanoparticles black-dyed lymph nodes play a role as SLNs in T1-2 colorectal cancers.

Without requiring time synchronization, protocol sequences can be used to design a simple and reliable channel access protocol for mobile ad hoc networks. This paper focuses on completely irrepressible (CI) sequences, which can be employed to allow each user to have at least one successful packet transmission within each sequence period for a completely asynchronous channel. Previous numerical studies have shown by using carefully designed CI sequences, the average delay performance can be improved than using ALOHA-type schemes. To gain a unique insight into the characteristics of the protocol, we present an analytical model for the delay performance of CI sequences. The accuracy of our analytical model is verified via numerical results.

Background The aim of this study was to evaluate the association between the number of nodes harvested and the rate of node positivity, and to evaluate the effect of carbon nanoparticles (CNPs) in improving lymph node detection and staging accuracy in patients who received neoadjuvant chemoradiotherapy (NCRT) followed by curative resection. Study Design Between September 2008 and June 2014, 152 consecutive rectal cancer patients treated with NCRT and curative resection were included. Forty-five patients underwent preoperative submucosal injection of CNPs (CNP group); the other patients underwent surgery only (control group). The relationship between the number of lymph nodes harvested and the rate of node positivity was investigated. A comparison of the number of harvested lymph nodes and the node positivity rate between the 2 groups was also performed. The lymph nodes in the CNP group were analyzed in detail. Results The rate of node positivity increased gradually from 8.6% in patients with 1 to 5 nodes assessed to 37.8% in patients with 17 to 44 nodes assessed. The number of lymph nodes harvested was an independent risk factor for node positivity (p = 0.036). The mean number of lymph nodes retrieved in the CNP group was more than in the control group (21.1 vs 8.0, p = 0.000). The percentage of patients with positive lymph nodes was lower than in the control group (19.6% vs 35.6%, p = 0.037). In the CNP group, of 58 metastatic lymph nodes, 45 (77.6%) were dyed. Of 37 metastatic lymph nodes smaller than 5 mm, 33 (89.2%) were dyed. Conclusions More precise oncologic prognosis assessment was provided for patients with rectal cancer after NCRT by increasing the number of lymph nodes counted using a dye-tracing method, indicating that the use of CNPs is beneficial.

Background: Lymphangiogenesis plays a significant role in metastasis and recurrence of gastric cancer. There is no report yet focusing on the modulation of VEGF pathway and lymphangiogenesis of gastric cancer by targeting Akt/mTOR pathway. This study aims to demonstrate the relationship between Akt/mTOR pathway and VEGF-C/-D in gastric cancer. Methods: We collected surgically resected gastric adenocarcinoma specimens from 55 consented patients. Immunohistochemistry staining of p-Akt, p-mTOR, VEGF-C, VEGF-D were performed and scored by two independent pathologists. The results were presented as staining intensity and positive staining cell rate. We also measured lymphatic vessel density (LVD) by D2-40 staining. Different dosages of p-Akt inhibitor LY294002 (12.5 μM, 25 μM, 50 μM) and p-mTOR inhibitor Rapamycin (25 nM, 50 nM, 100 nM) were given to gastric cancer cell line SGC-7901 in vitro. The inhibition rate of cell growth was tested by MTT at 24 h, 48 h and 72 h, respectively and protein expressions of Akt, p-Akt, mTOR, p-mTOR, VEGF-C and VEGF-D were examined by Western blot. Results: The positive staining rates of p-Akt, p-mTOR, VEGF-C and VEGF-D in 55 gastric cancer clinical specimens were 74.54%, 85.45%, 72.73% and 58.18%. p-Akt and p-mTOR were positively correlated with VEGF-C and VEGF-D (p < 0.01). The LVD increased with incremental tendency of staining intensity of p-Akt, p-mTOR, VEGF-C and VEGF-D. LY294002 or Rapamycin significantly suppressed SGC-7901 cell growth and the inhibition rate was dose and time dependent (p < 0.001). In addition, the protein expression of p-Akt and p-mTOR were positively correlated with that of VEGF-C and VEGF-D (p < 0.05). Conclusions: The level of LVD in gastric cancer specimens was significant higher than that of normal gastric tissue and was positively correlated with p-Akt, p-mTOR, VEGF-C and VEGF-D. Inhibition of p-Akt and p-mTOR, in vitro, decreased tumor cell VEGF-C and VEGF-D significantly. Therefore, we concluded that lymphangiogenesis of gastric cancer might be related to Akt/mTOR-VEGF-C/VEGF-D axis.

The wireless personal area network (WPAN) is designed for short-range connectivity among fixed or portable moving devices. The ultra-wideband (UWB) technology is being defined as the physical-layer (PHY) support for the high-rate WPAN. At medium access control (MAC) layer of the WPAN, a delayed acknowledgment (Dly-ACK) or burst-ACK (B-ACK) scheme is introduced to improve the channel utilization by reducing the overhead of ACK. In this paper, the authors first study the delay performance of the Dly-ACK scheme. An analytical model is developed for the Dly-ACK mechanism, and the delay is decomposed into queuing delay and delivery delay. These delay metrics are derived, and some important observations are obtained. In particular, there exists an optimal burst size, which is determined by the input traffic load and is very insensitive to the channel error rate within a normal error-rate range. It is also demonstrated that Dly-ACK cannot work properly if the burst size is fixed. The authors then propose a dynamical Dly-ACK scheme that can adaptively change its burst size according to the queue buffer size. Simulation results show that the dynamical scheme can improve the delay performance significantly.

Dly-ACK scheme in IEEE 802.15.3 MAC is designed to reduce the overhead of the ACK frame in MAC layer and improve the channel utilization. However, how to using the Dly-ACK is open for implementation. In this paper, we propose an adaptive Dly-ACK scheme for both TCP and UDP traffic. We first point out the problems of applying fixed Dly-ACK scheme to these two traffic scenarios and show that the system performance is rather poor and the causes of these problems are presented. Based on our observations, two enhancement mechanisms for fixed Dly-ACK are then proposed. The first one is to request the Dly-ACK frame adaptively or change the burst size of Dly-ACK according to the transmitter queue status. The second is a retransmission counter to enable the destination DEV to deliver the MAC data frames to upper layer timely and orderly. Simulation results show that, with our enhancements, the system performance can be improved significantly compared with the conventional Imm-ACK and fixed Dly-ACK. We also investigate the impacts of some important parameters such as the buffer size on the system performance. Some important guidelines for the Dly-ACK design are given. Finally, it is worth to point out that our Dly-ACK enhancements are compatible with the standard and it is transparent to the upper layer protocols, i.e., either UDP or TCP.

To utilize Bluetooth as a layer 2 multi‐hop subnet for global IP network, there are two missing protocols in current Bluetooth stack: network formation and routing. In this paper, we propose our network formation and routing protocols optimized for such Bluetooth subnset usage scenarios to fill this gap. In this paper, we first present some observations on performance degradations of Bluetooth PAN due to network topologies and topology change when radio independant protocols are implemented. And then we analyze the reason of performance degradation. Based on our analysis, we first propose a flexible scatternet formation algorithm under conference scenario for multi‐hop communication. By using proposed method, scatternet can be formed flexibly with star, mesh, or linked line based on several parameters like number of maximum piconets that a gateway Bluetooth device can participate, and whether loops are needed in the resulting scatternet to achieve better network performance. To utilize topology information in multi‐hop communication, we propose a Cross‐layer Optimized Routing for Bluetooth (CORB) CORB is a QoS‐extended AODV routing protocol with mainly two optimizations between networking layer and underlying Bluetooth MAC layer. The first optimization is to use a new load metric. (LM) in QoS routing protocol instead of number of hops in conventional best effort routing. LM is derived from estimation of nodes’ link bandwidth, which reflects the different roles of nodes in Bluetooth scatternet. This proposal helps routing protocol to bypass heavily loaded nodes, and find route with larger bandwidth. The second optimization is to adjust LM and some MAC layer parameters in response to the unstable network topology caused by movement and change of indoor radio condition. Finally, We present some simulation and experiment results based on implementation, which prove the effectiveness of our protocols.

Topology of a network greatly affects the network performance. Depending on the purpose of a network, a specific topology may perform much better than any other topologies. Since the ad hoc networks are formed for a specific purpose, determining, and constructing the network topology based on the application requirements will enhance system performance. This paper proposes Bluetooth scatternet forming protocol in which the network topology is determined by three parameters. The parameters affecting the topology are the number of maximum slaves in a piconet, the number of maximum piconets that a gateway Bluetooth device can service, and the number of loops needed in the formed scatternet. These parameters can be read from a script file prior to the network formation. This process of reading the important parameters from the file would give users freedom in determining the network topology. The proposed protocol also includes a role negotiation process to accommodate different capabilities of the participating devices. The negotiation process of the protocol allows the resource-limited nodes to participate in the network. Different types of scatternet topologies like star, mesh, ring and line can be formed by specifying the parameters. This paper also discusses theoretical information necessary for calculating network topologies in detail. The protocol is verified with help of simulations, and implementations using commercially available Bluetooth devices. The detailed results are also presented in this paper.

This letter provides a saturation throughput analysis of DCF by extending the Tinnirello's model into the non-ideal channel. In contrast to the existing models which also analyze the DCF under the non-ideal channel, our model provides more accurate results owing to taking into account anomalous slots and the freezing of backoff counter.

In order to reduce the tee-joint's thickness and manufacturing cost, a series of large diameter and high-strength tee-joints are manufactured based on the equivalent strength design principles. The burst pressure of tee-joints is obtained directly by a series of burst tests. In addition, numerical simulations are carried out to evaluate the burst pressure capacity of a tee-joint. The influence of the fillet radius and the thickness of the branch are also discussed. The results of this paper may provide guidance in the design and manufacture of a tee joint.

It is difficult to inspect a tank floor when tank is in service. The conventional inspection of a tank floor after it is opened and cleaned is time-consuming and is a high cost. So the in-service inspection of above-ground storage tank floors with Acoustic Emission (AE) technique is accepted by petrochemical industry more and more. Until now more than 70 tanks have been inspected with AE technology in PetroChina Pipeline Company. In this paper our method is introduced and the influencing factors for AE testing are discussed. The reliability of AE testing is mainly concerned by comparing the results of AE testing with the one of conventional nondestructive testing (NDT). The study concluded that the AE inspection is a useful and economic tool for prioritizing the tank maintenance.

In-service inspection of aboveground storage tanks with acoustic emission technique is accepted by petrochemical industry more and more in the world. PetroChina Pipeline R&D Center has inspected dozens of large storage tanks with acoustic emission technology to evaluate the corrosion situation of tank floors. In this chapter our method is introduced. And the comparison between the results of acoustic emission testing and conventional NDT is described in detail in order to verify the effectiveness and reliability of AE tank floor inspection. Some typical examples are demonstrated.

Supercapacitors are important energy storage technologies in fields such as fuel-efficient transport and renewable energy. State-of-the-art supercapacitors are capable of supplanting conventional batteries in real applications, and supercapacitors with novel features and functionalities have been sought for years. Herein, we report the realization of a new concept, a smart supercapacitor, which functions as a normal supercapacitor in energy storage and also communicates the level of stored energy through multiple-stage pattern indications integrated into the device. The metal-oxide W18O49 and polyaniline constitute the pattern and background, respectively. Both materials possess excellent electrochemical and electrochromic behaviors and operate in different potential windows, -0.5-0 V (W18O49) and 0-0.8 V (polyaniline). The intricate cooperation of the two materials enables the supercapacitor to work in a widened, 1.3 V window while displaying variations in color schemes depending on the level of energy storage. We believe that our success in integrating this new functionality into a supercapacitor may open the door to significant opportunities in the development of future supercapacitors with imaginative and humanization features.

The capability of imaging and detecting single DNA molecules is critical in the study, analysis, and applications of DNA. Fluorescence imaging is a widely used method, but it suffers from blinking and photobleaching, and fluorescence tags may block or affect binding sites on DNA. We report on label-free imaging of single DNA molecules with a differential plasmonic imaging technique. The technique produces high contrast images due to the scattering of surface plasmonic waves by the molecules and the removal of background noises and interference patterns, allowing for quantitative analysis of individual DNA molecules. Simulation of the images based on a scattering model shows good agreement with the experiment. We further demonstrate optical mapping of single DNA molecules.

To identify the risk factors for apical node metastasis in colorectal cancer (CRC) patients who underwent laparoscopic radical resection with D3 lymphadenectomy. The subjects were 578 consecutive patients who underwent laparoscopic radical resection with D3 lymphadenectomy for CRC between February, 2003 and December, 2009. The Cox proportional regression model was used to evaluate the association between apical node metastasis and survival and the logistic regression model was used to identify the risk factors for apical node metastasis. Thirty patients (5.2 %) had apical node metastasis, which was an independent risk factor for poor disease-free survival [hazard ratio (HR) = 3.02, P = 0.019]. Multivariate logistic regression analysis revealed that poor differentiation [odds ratio (OR) = 4.58, P

A more flexible grounding resistance calculation method, based on finite element analysis (FEA) method, is suggested, which is especially suitable for optimization cathodic protection (CP) ground-bed arrangement. As compared with traditional grounding resistance evaluation method, which is only suitable for the case of each anode rod in a straight line, the FEA method can calculate grounding resistance of ground-bed at any arrangement. Moreover, a realistic soil resistance rate, usually varying with depth, can be included in calculation model. The detailed steps for this method can be summarized as follow: building a 3D geometric model according to general design, meshing the geometric model, setting reasonable boundary conditions, solving and post-solving the grounding resistance with ohmic law. To further explain this procedure, a realistic CP ground-bed displacing project is presented, which includes displacing the original CP ground-bed firstly and re-designing a new ground-bed within a limited area (5m×30m). A new CP ground-bed design, compared with traditional design, 2×7, 14 anode rods dispersed in two parallel groups, are calculated firstly. The results show that this design can not meet the grounding resistance requirement. Another 4 designs, with anode rods arranged as 2×6, 2×8, 2×9, 3×6 are calculated respectively. Finally, the design 2×8 is recommended from the view of economy and practicability.

Due to rapid development of HVAC transmission lines, AC electric railways and oil and gas pipelines, these lines will inevitably cross or lie parallel to each other. At these positions, pipelines will be subject to serious interferences. In most situations, only the results of an interference are detectable, with no clue as to what caused the problem. This paper presents a new method designed to solve AC interference. When the interference source cannot be determined, AC voltages of buried pipelines are first measured and the AC interference is simulated. Furthermore, a mitigation method is built using computer software. After mitigation devices are installed on the pipeline, AC voltages are simulated once more and compared with field-measured values. The result shows that the simulated AC interference and the subsequent mitigation method built with computer software are more efficient.

In a real wireless channel, both a channel bit error and a collision between competition stations can cause a data frame loss. Moreover, DCF always assumes that a data frame loss is due to the collision and the contention window will double in next transmission. In fact, we think that the contention window shall be difference between channel bit error and collision. In this paper, we propose a ideal mechanism LD-DCF which can completely differentiate between the two reasons of a data frame loss. An analytical model is given to demonstrate the efficiency of LD-DCF. NS-2 simulation is also used to validate the LD-DCF. By the theoretical and simulation results, the LD-DCF can improve the throughput significantly, especial for the high channel bit error and low contending stations (i.e. the low network traffic).

In IEEE 802.16e (WiMAX), each data burst consists of multiple MPDUs. The MPDUs of one data burst are distinguished from each other according to the generic MAC header (GMH). The GMH contains the length information of MPDU. If the GMH is damaged, it doesn’t know what’s end of the MPDU. As a result, the damaged MPDU and successive MPDUs in the data burst shall be discarded even if the successive MPDUs are correct received. In this paper, we point out the cursory discarding and propose a recovering scheme to improve the network bandwidth. KeywordsIEEE 802.16e, WiMAX, HCS, CRC

Stray current interference may cause pipeline corrosion, which will result in premature failure of pipeline and potential safety problem to the persons who would touch the pipe during the work. The results of systematic field survey of the AC interference on an oil products pipeline showed that the range of quasi-stable AC interference was more than 20 km. Moreover, the risk of two separate pipeline sections among them was medium or worse. The relationship among corrosion rate, AC interference voltage, and AC interference current density was summarized after on-site tests. Finally, some mitigation suggestions were proposed.

Genetic variations in the gene XPC may be associated with increased risk for gallbladder cancer (GBC). In this study, we detected two non-synonymous polymorphisms in XPC (Ala499Val and Lys939Gln) in 334 cases of GBC and 329 subjects of hospital-based age- and sex frequency-matched controls in China using a polymerase chain reaction-restriction fragment length polymorphism assay. Allelic association analysis for the two single-nucleotide polymorphisms (SNPs) showed that the risk allele T of Ala499Val was significantly associated with GBC [odds ratio (OR)=1.40, 95% confidence interval (CI): 1.11-1.76, P=0.005), with a population attributive risk of 5.3%. Logistic regression analysis revealed that Ala499Val CT heterozygote (OR=1.56, 95% CI: 1.13-2.14, P=0.002) and TT homozygote (OR=1.93, 95% CI: 1.04-3.55, P=0.048) had a significantly increased risk compared with CC homozygotes. Genetic analysis suggested that either the SNPs directly exert an effect or the linked functional gene impact of the disease trait likely follows an additive or dominant model. Gene interaction analysis demonstrated that the effects of XPC diplotypes (defined as the number of risk genotypes at the two SNP loci) were highly dependent on gallstone. The data from this case-control study indicated that XPC exonic variants contributed to the risk of GBC in this Chinese population.

The surface potential distribution of buried X80 steel under cathodic protection was calculated by finite element method. After comparing the results of simulation and experiment, the advantages and disadvantages of the numerical simulation method used in the present paper were discussed.

In order to achieve safety and reliability of long-distance gas transmission pipeline installed in seismic region while obtaining economical benefit by reducing material and construction cost, it is essential to apply the high-strength linepipes with sufficient strain capacity against buckling and weld fracture by seismic ground movement. At the same time, it is quite important to develop appropriate material requirement for strain capacity depending on the pipe dimension and strain demand of the region where the pipeline is installed. Grade X80 heavy gauge linepipes with excellent deformability were mass produced by applying advanced plate manufacturing technologies. These linepipes exhibit low Y/T and high uniform elongation in the longitudinal direction even after pipe coating. Strain capacity of the pipe against bending deformation with internal pressure was verified by conducting full scale pipe bending testing. In this paper, production results of high strain X80 linepipes for the application in long-distance pipelines in seismic region and full scale pipe bending and hydraulic burst test results were introduced.Copyright © 2010 by ASME

With the sharply rising demand of oil and gas, the pipeline industry has been experiencing a rapid development in recent years. Pipelines in the areas of ground movement from slope instability, seismic sideslip, loess collapse, mining subsidence, frost heave and thaw settlement in discontinuous permafrost can experience displacement-controlled plastic strain. The current paper describes the application of strain-based design of pipelines and introduces relevant codes, standards, and criteria of other countries. Some major issues in strain-based design such as geologic conditions, strain limits, mechanical performance, etc., are mentioned. The prospect of strain-based design of pipelines is discussed with reference to the geologic conditions and the state of the pipeline industry. Finally the requirements on parameters of line pipe materials, including yield stress, yield and tensile strength ratio, stress ratio, weld mismatch, anisotropy etc., and their influence on strain-based design are discussed.Copyright © 2009 by ASME

The 2nd West-East Pipeline Project which are building now is the longest of X80 gas pipeline in China even in the world. The geological conditions along it are very complicate. Both stress-base and Strain-based design are all used in the pipeline design. Strain-based design are considered when the pipeline shall via seismic activities, fault crossing and other geological disaster area where ground moving may happen. The pipe which will be used in this kind of special area shall have some special properties besides the properties requirement of the ordinary line pipe. So Tubular Goods Research Center of China National Petroleum Corporation drafted “the Supplementary Technical Specification of High Strain LSAW Line Pipe for the 2nd West-East Pipeline Project”. In this specification, the strain capacity of current X80 line pipe and the testing methods for the mechanical properties are considered. In the mean time, the risk of aging when the pipes are coated is also be noted, and the coating temperature is specified in the specification. Certainly, besides the deformability of the pipe, strain-based design also needs more measures from pipeline construction, girth welding, etc. to ensure the pipeline can endure certain deformation. This paper introduced the general situation of the 2nd West-East Pipeline Project, and several key issues in the specification of high strain line pipe used in strain-based designed districts. At the end of the paper, the mechanical properties and the deformability of X80 pipe which are possible to be manufactured and used in this gas line are be presented.Copyright © 2008 by ASME

The use of strain based design in pipeline technology has been widely discussed during the last decade for pipelines in harsh environment. In such cases pipelines should be designed based on strain criterion. Strain based design poses a number of challenges, particularly on pipe size and material properties. This paper presents preliminary studies on prediction of buckling strain and buckling mode for X80 high-strain line pipe by finite element methods based on full-scale test. The effects of several parameters such as internal pressure, material properties pipe size and geometric imperfection, were investigated to predict the critical strain for 48″ diameter line pipe under compression and pure bending with 12MPa internal pressure. Material parameters of a specification for high strain line pipe were analyzed to promote its application in the 2nd West-East pipeline of China National Petroleum Corporation.Copyright © 2008 by ASME

This paper proposes a method to form a Bluetooth scatternet under the conference scenario. The principles and formulas for calculating network topologies are discussed in detail. The method is proved by implementation using commercially available Bluetooth devices. The scatternet topology can be star, mesh, ring and linked line, which is controlled by changing parameters like the number of maximum slaves in a piconet, the number of maximum piconets that a gateway Bluetooth device can participate, and whether loops are needed in the resulting scatternet. In this paper, we also present a lot of testing results from forming the real scatternet.

This paper proposes a new authentication scheme for accessing contents, services and applications in both mobile device and Internet. A user first divide all the contents, services and applications in both mobile device and the Internet into four groups according to their importance: extremely confidential group (ECG) has security level SL=1, very confidential group (VCG) has SL=2, confidential group (CG) with SL=3 and free accessible group (FAG) with SL=4. If it is Internet content or service or application, the pair of username and password necessary for accessing it is put into the group. In order to access the items in the four groups, four authenticating methods are defined, which generates four active usage levels (AUL). Fingerprint plus password1 authentication generates AUL=1, which grants the right to access all four groups. Fingerprint alone generate AUL=2, which grants the right to access groups of VCG, CG and FAG. Password2 authenticating generates AUL=3, which grants right to access CG and FAG. Null authentication generates AUL=4, which is the default AUL and can only access items in FAG. Once an AUL is generated, user can not only access corresponding groups of information stored in the device but also use that mobile device to access corresponding groups of her/his Web accounts seamlessly without memorizing usernames and passwords. Whenever the user wants to access information stored in the mobile devices, or Web accounts provided by a third party, the security middleware obtains SL required to access them, compares the SL with the AUL. If the AUL is equal to or higher than the SL, the access is granted seamlessly and transparently to the user; otherwise, it asks to authenticate again to gain higher AUL, or the access is denied. After the access right to a device is granted, the user can at any time reset the AUL to 4, or the AUL can be set to 4 automatically after a predefined idle period.

In this paper, we propose a new authentication and control scheme for accessing the content both in mobile devices and on the Internet. The user does not need to provide or remember usernames and passwords when she/he accesses Web accounts from the mobile device once authentication to the device is achieved. We also analyzed the security performance of our scheme and compared it with existing persistent cookies, passport services and the common password method. The proposed scheme offers superior protection even if the device is misplaced or lost. The proposed authentication scheme will enable mobile centric communications to be more secure and easier to use.

The Dly-ACK scheme in IEEE 802.15.3 is designed to reduce the overhead of the ACK and improve the channel utilization. However, the way to use the Dly-ACK is open for implementation. In this paper, we first investigate the problems of applying the fixed Dly-ACK scheme to the TCP stream and show that the TCP performance is rather poor. Then, we propose two enhancement mechanisms for TCP with Dly-ACK over the 802.15.3 system. The first one is to request the Dly-ACK frame adaptively or change the burst size of Dly-ACK according to the queue size. The second is a retransmission counter to enable the destination DEV to deliver the packets to the upper layer timeously and in orderly fashion. Simulation results show that, with our enhancements, the TCP throughput can be improved more than 40% compared with the conventional Imm-ACK. We also investigate the impacts of some important system parameters such as the buffer size on the TCP performance. Some guidelines for the Dly-ACK design are given. Finally, it is worth pointing out that our enhancements are compatible with the standard.

In this paper, we present some observations and analysis on Bluetooth PAN's performance degradation in multi hop network based on our experiments. We highlight a situation in which control packets can be received properly but not data packets, as well as its effects on scatternet performance. Based on our analysis, we propose a cross-layer optimized routing protocol for Bluetooth (CORB), which outperforms AODV based routing protocols. CORB is a QoS-extended AODV routing protocol that is optimized for Bluetooth MAC. It has two unique characteristics. First, it uses a new load metric (LM) in QoS routing protocol instead of the number of hops as in conventional best effort routing. LM reflects nodes' link bandwidth with respect to Bluetooth nodes' role in the scatternet. This helps the CORB to bypass heavily the loaded nodes, and find routes with larger bandwidth. Second, LM and some MAC layer parameters are dynamically adjusted in response to the changes in radio conditions. These two characteristics of CORB contribute to its improved stability, and rapid response to changing radio conditions

This paper focuses on the impact of topology on Bluetooth personal area network. We first present some observations on performance degradations of Bluetooth PAN due to network topologies, and then analyze its reason. Based on our analysis, we propose a flexible scatternet formation algorithm under conference scenario for multi-hop communication. By using proposed method, scatternet can be formed flexibly with different topologies under a controlled way. To utilize topology information in multi-hop communication, we propose a new link metric Load Metric(LM) information in multi-hop communication, we propose a new link metric Load Metric(LM) instead of number of hops. LM is derived from estimation of nodes’ link bandwidth, which reflects different roles of nodes in Bluetooth scatternet. This proposal helps routing protocol to bypass heavily loaded nodes, and find route with larger bandwidth. We present some experimental results based on implementation, which prove the effectiveness of our protocols.

In this paper, performances when go-back-N (GBN) and selective repeat (SR) ARQ are applied in high speed ATM networks are studied. They can be used in regenerators or completely from transmitter to end receiver. Details of cell format, format of acknowledgment cell, CRC code and analytical results of throughputs, traffic increments as well as buffer requirements of the two proposed ARQs are given in the paper. A method of estimating the error detecting capability is developed. Finally, The operations of transmitter and receiver are designed and simulated. Analytical and simulation results reveal that high throughput can be achieved and buffer size is acceptable.

a College of Bioengineering, Key Laboratory for Biomechanics and Tissue Engineering of the State Ministry of Education, Chongqing University, Chongqing 400044, PR China b Department of Clinical Pharmacology, Pharmacy School of Jinan University, Guangzhou 510630, PR China c School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 5110080, PR China d School of Pharmaceutical Sciences, Wenzhou Medical College, Wenzhou 325000, PR China e Department of Biophysics, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, PR China