bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydroelastic Stability and Vibration of a Large Reactor Pendulum Structure
Authors: Meyer Gregory A. , Banyay Gregory A. , Maeby Samuel A. , Sidener Scott E. , Schwirian Richard E.
Published: December 2013

Parallel-flow induced vibrations of both large and small reactor internal structures have been analyzed in the past for multiple reactor types. In parallel flows relating to annular and leakage flows, the possibility for significant wear issues can arise and need to be assessed as has been shown throughout the literature. With parallel flow induced vibration, a particular fluid-structure interaction known as hydroelastic instability can arise. If hydroelastic instability occurs, damage to components can be severe and/or catastrophic. This particular phenomenon has been studied in the literature and a few empirically derived methodologies have been published to evaluate the potential for hydroelastic instability to occur in both a limited number of specific geometries and some generic geometries. However, as structural components and their associated flow field characteristics can vary significantly and because of the potential for catastrophic damage to reactor components and the associated costs, a more detailed first principles approach may be warranted to further determine if hydroelastic instability is not only possible, but probable.

A potential design for a reactor internals test in which part of the upper internals would exhibit significant annular parallel flow velocities is analyzed for the potential onset of hydroelastic instability. In particular, the upper core plate, which is attached to the rest of the upper internals via support columns in a pendulum setup with the attachment/pivot point at the upper pressure vessel head flange, is temporarily designed to carry a significant non-prototypic pressure drop causing significant upper core plate to core barrel gap flow velocities and potential instability issues. Due to the different geometry of this hardware configuration compared to those found in the literature, both an empirically-based stability analysis from the literature and a first-principles based hydroelastic stability analysis are conducted. The first-principles analysis derives and solves the time-dependent equations of motion and mass conservation for both the fluid and structure and compares the results proximity to stability limits found in the literature. A comparison of the empirically based stability assessment with the first-principles stability analysis is made. Furthermore, an assessment of the probability for the onset of hydroelastic instability of the upper internals assembly is made via a Monte Carlo simulation using the first-principles analysis methodology.
Analysis and Active Control of the Flow Around Two Following Ahmed Bodies
Authors: Bruneau Charles-Henri , Khadra Khodor , Mortazavi Iraj
Published: December 2013

The aim of this work is on the one hand to show that the drag coefficient of a bluff body is mainly linked to the vortical structures in the close wake of the body. Thus an active control can be used to push away these structures to decrease the pressure forces at the back and consequently to reduce the drag coefficient. On the other hand a study of the platooning is performed. When two bodies are following each other with a short distance between them, the presence of the first body changes significantly the pressure force in front of the second one as a weak flow is present in between. The first body plays the role of a buckler and so the second body has to face completely different flow conditions. Therefore the drag of the second body is drastically reduced as shown on the results. Finally a control of the flow around the first body gives promising and surprising results.
CFD Based Modeling of Wave Propagation in Liquid Transmission Line Junctions
Authors: Fries Clemens , Manhartsgruber Bernhard
Published: December 2013

Wave propagation effects are of increasing importance in simulation models for fluid power applications due to rising demands for both the accuracy of predicted system responses as well as the range of interesting operating frequencies. Well documented examples can be found in technologies such as fuel injection for internal combustion engines or hydraulically driven punching machines. The distribution system for the pressurized fluid is predominantly made up of pipes and hoses as well as cylindrical bores in the housings of various components. These cylindrical geometries lend themselves conveniently for modeling as a network of elements with a one or two-dimensional spatial representation. The junctions between these elements, for instance a sharp elbow bend or a T-junction between three pipelines is very often idealized as a lossless Kirchhoff-type node. The present paper shows a comparison of transmission line modeling based on the well known frequency-dependent friction theory for transient laminar flow of a weakly compressible viscous fluid in transmission lines with a CFD model resolving the local effects occurring at a junction or intersection of cylindrical elements. Results are given for a 90 degree elbow under step excitation with the material parameters of a typical ISO 46 mineral oil based hydraulic fluid. These results can be used in order to assess the importance of including the usually neglected local effects at the junctions. In further work they will form the basis for reduced order dynamic models of transmission line junctions.
Micropower From Tidal Turbines
Authors: Polagye Brian L. , Cavagnaro Robert J. , Niblick Adam L.
Published: December 2013

In addition to utility-scale power generation (e.g., rated capacities greater than 106 W), there are also possibilities for tidal current generation at the micro-scale (e.g., rated capacities less than 102 W) that could provide power to autonomous oceanographic instrumentation. This paper presents performance characteristics of a high-solidity, helical, cross-flow turbine rotor for a tidal current micropower system. Studies are conducted on a 1/4-scale turbine in a laboratory flume and a full-scale turbine prototype using open-water tows. Results suggest this type of turbine rotor can achieve efficiencies as high as 25% and can smoothly self-start at water velocities less than 0.5 m/s. The sharp peak around optimal efficiency displayed by the power performance curves suggests a need for generator control in a micropower system using this type of rotor.
Three Dimensional Flow Around a Biomimetic Unbounded Flapping Cantilever
Authors: Eastman Andrew , Kimber Mark
Published: December 2013

Macro-sized cantilevers oscillating in a fluid have been employed in applications ranging from thermal management to propulsion and represent a realistic tradeoff between full biomimicry and ease of fabrication. Surprisingly, the flow field generated upstream and downstream of the cantilever remains poorly understood. In order to properly control the resulting flow, further experimental and numerical studies are needed. From a two dimensional perspective, comprehensive analysis has been done, primarily through employing a single, very wide cantilever. However, many applications necessitate the usage of oscillating cantilevers whose oscillating amplitude is comparable to their width. As the region of analysis moves closer to a corner, where two edges of the slender cantilever meet, the flow becomes extremely three dimensional, rendering the two dimensional analysis tools less useful. The following paper seeks to further understand the highly three dimensional nature of the flow in addition to providing further insight into optimized flow control. Two perpendicular flow planes are analyzed in order to gather the x, y and z directional flow velocities using standard Particle Image Velocimetry measurements. It is shown that under certain circumstances, the resulting flow is atypical of what one would expect from a simple extrapolation from previous two dimensional flow analyses.
Stability Analysis of Hydropower Stations With Complex Flow Patterns in the Tailrace Tunnel
Authors: Zhou Jianxu , Cai Fulin , Hu Ming
Published: December 2013

For some special tailrace tunnels in the hydropower stations, including the changing top-altitude tailrace tunnel and the tailrace tunnel with downstream reused flat-ceiling diversion tunnel, during normal operation and hydraulic transients, the flow patterns inside are relatively complex mainly including the free-surface pressurized flow and partial free flow if the tail water level is lower than the top elevation of tunnel’s outlet. These complex flow patterns have obvious effect on system’s stability, and can not be simulated accurately by the traditional models. Therefore, a characteristic implicit model is introduced to simulate these complex flow patterns for further stability analysis. In some special cases, the characteristic implicit model also fails to completely simulate the mixed free-surface pressurized flow in the flat-ceiling tailrace tunnel. A new method is presented based on both experimental research and numerical simulation, and then, system’s stability is analyzed by compared with traditional ordinary boundary condition. The results indicate that, with different simulation models for the complex water flow in the tailrace tunnel, system’s dynamic characteristic can be actually revealed with the consideration of the effect of complex flow patterns in the tailrace tunnel on system’s stability and regulation performance.
Numerical Simulation and Experimental Study of Cabin-Airflow and Transport of Gas-Mixtures in Aircraft Cargo Compartments: Model Validation
Authors: Zur Malte , Otremba Frank , Klippel Alexander , Leder Alfred
Published: December 2013

Dangerous goods are transported as air freight in commercial aircrafts. Using plastic jerrycans or plastic containers, liquids or gases can escape by leakage or permeation effects. Prior research by the German Federal Institute for Materials Research and Testing (BAM) showed that the lower explosion limit can be reached when transporting dangerous goods in sea-freight containers under normal transportation situations. This motivated the presented study of the transportation situation of dangerous goods in cargo compartments of commercial airplanes. The scope of this paper is to present the experimental method used for validating a numerical model for CFD (Computational Fluid Dynamics) simulations. The CFD model will be used in a future study to evaluate the potential risk from transporting dangerous goods.

The objective of this paper is to present the model mock-up of an aircraft cargo compartment and some examples of three dimensional velocity profiles of the air flow in the mock-up. The velocity profiles are calculated using numerical simulations and measured by Laser-Doppler-Anemometry (LDA) experiments. The mock-up is a generic model of a wide-body aircraft lower deck cargo compartment in a 1:10 scale. Geometry, air exchange rates and inlet as well as outlet flow conditions in the cargo compartment are modeled using realistic boundary conditions. The commercial CFD (Computational Fluid Dynamics) code ANSYS CFX 14 is used for numerical flow simulations applying RANS (Reynolds-Averaged-Navier-Stokes) equations and turbulence models. The turbulence models studied are the renormalization group k-ε-model (RNG), the Reynolds-Stress model by Launder, Reece and Rodi (LRR) and the SST-k-ω-model by Menter (SST).

The flow measurement with LDA in the mock-up of a cargo compartment proves to be a feasible method for producing data to validate CFD simulations. Qualitative evaluation of the results shows a good overall agreement between numerical and experimental results. The experimental validation indicates that the implemented CFD model is capable of reproducing the flow situation in the model mock-up.
Finding the Right Partner in a 3D Genome
Authors: Rocha Pedro P. , Chaumeil Julie , Skok Jane A.
Published: December 2013

The three-dimensional organization of the genome plays a role in controlling legitimate and illegitimate DNA recombination.
Improving Biologic Drugs via Total Chemical Synthesis
Authors: Hsieh-Wilson Linda C. , Griffin Matthew E.
Published: December 2013

The chemical synthesis of a single glycosylated form of erythropoietin may help elucidate the functions of its sugars and tailor its properties.

[Also see Report by

Wang
et al.

]
Coming to an Airport Near You
Authors: McLean Angela R.
Published: December 2013

Definition of an effective distance between airports helps to explain the spread of epidemics across the global aviation network.

[Also see Report by
Brockmann and Helbing
]
Michael Neuberger (1953–2013)
Authors: Sale Julian E. , Patel Ketan J. , Batista Facundo D.
Published: December 2013

A sharp immunologist who unraveled the mechanisms of antibody diversification helped to launch a biomedical engineering revolution.
Reading the Bones
Authors: Armelagos George J.
Published: December 2013

The modern era of disease emergence and reemergence is attributed to issues ranging from the deterioration of the environment, which brings humans in contact with pathogens that jump species barriers, to globalization, which is expanding the reach of pathogens beyond their former geographic boundaries. The transition from foraging to agriculture about 10,000 years ago accelerated the emergence of infectious disease. But it was the rise in social inequalities within and between societies that created disparities in disease risks and access to treatments, conditions that are still evident in today's world. The calls for improving surveillance, research, vaccines, and behavioral change are indeed urgent, but what is also worrisome is the lack of an evolutionary perspective in formulating new strategies to confront this modern disease-scape. Paleopathology—the study of ancient diseases—not only provides an archaeological record of the adaptations and lifeways of ancient peoples, it is a source of information on the evolutionary epidemiology of infectious diseases. Reading the bones of the ancient dead can guide how we confront infectious diseases today.
Lick Observatory in Trouble as Austerity Starts to Bite
Authors: Bhattacharjee Yudhijit
Published: December 2013

Rocked by budget cuts, the 125-year-old Lick Observatory near San Jose, California, is losing staff and faces closure or conversion to a public museum.
Advocates Protest the Cost of a Hepatitis C Cure
Authors: Cohen Jon
Published: December 2013

A new hepatitis C drug promises to revolutionize treatment—for the relatively few people in the world who can afford it.
Europe Readies Peerless Star Mapper
Authors: Clery Daniel
Published: December 2013

A soon-to-be-launched European satellite called Gaia will map the positions and movements of a billion stars with unprecedented precision.
The Thousand-Year Graveyard
Authors: Gibbons Ann
Published: December 2013

Scientists uncover a tortured history of disease and death from the Middle Ages onward.
Stefan Behnisch and the Good Client
Authors: Mervis Jeffrey
Published: December 2013

The German architect is recognized for his smart, sustainable buildings. But an innovative science lab also requires a good partner.
Large-Scale Prospective T Cell Function Assays in Shipped, Unfrozen Blood Samples: Experiences from the Multicenter TRIGR Trial
Authors: Hadley David , Cheung Roy K. , Becker Dorothy J. , Girgis Rose , Palmer Jerry P. , Cuthbertson David , Krischer Jeffrey P. , Dosch Hans-Michael
Published: December 2013

Broad consensus assigns T lymphocytes fundamental roles in inflammatory, infectious, and autoimmune diseases. However, clinical investigations have lacked fully characterized and validated procedures, equivalent to those of widely practiced biochemical tests with established clinical roles, for measuring core T cell functions. The Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR) type 1 diabetes prevention trial used consecutive measurements of T cell proliferative responses in prospectively collected fresh heparinized blood samples shipped by courier within North America. In this article, we report on the quality control implications of this simple and pragmatic shipping practice and the interpretation of positive- and negative-control analytes in our assay. We used polyclonal and postvaccination responses in 4,919 samples to analyze the development of T cell immunocompetence. We have found that the vast majority of the samples were viable up to 3 days from the blood draw, yet meaningful responses were found in a proportion of those with longer travel times. Furthermore, the shipping time of uncooled samples significantly decreased both the viabilities of the samples and the unstimulated cell counts in the viable samples. Also, subject age was significantly associated with the number of unstimulated cells and T cell proliferation to positive activators. Finally, we observed a pattern of statistically significant increases in T cell responses to tetanus toxin around the timing of infant vaccinations. This assay platform and shipping protocol satisfy the criteria for robust and reproducible long-term measurements of human T cell function, comparable to those of established blood biochemical tests. We present a stable technology for prospective disease-relevant T cell analysis in immunological diseases, vaccination medicine, and measurement of herd immunity.
Comparison of the Cerebrospinal Fluid (CSF) Toluidine Red Unheated Serum Test and the CSF Rapid Plasma Reagin Test with the CSF Venereal Disease Research Laboratory Test for Diagnosis of Neurosyphilis among HIV-Negative Syphilis Patients in China
Authors: Zhu Lin , Gu Xin , Peng Rui-Rui , Wang Cuini , Gao Zixiao , Zhou Pingyu , Gao Ying , Shi Mei , Guan Zhifang , Seña Arlene C.
Published: December 2013

In this study, we aimed to investigate the performance of nontreponemal antibody tests in cerebrospinal fluid (CSF) specimens from syphilis patients. From September 2009 to September 2012, CSF specimens were collected at the Shanghai Skin Disease Hospital in Shanghai, China, from 1,132 syphilis patients without HIV infection, including 154 with symptomatic and 56 with asymptomatic neurosyphilis. All of the CSF specimens underwent testing with a rapid plasma reagin (RPR) test, an RPR-V (commercial RPR antigen diluted 1:2 in 10% saline) test, the toluidine red unheated serum test (TRUST), and the Venereal Disease Research Laboratory (VDRL) test. Specificities, sensitivities, positive predictive values (PPVs), negative predictive values (NPVs), and kappa values were calculated to determine the performances of the tests. We compared results of the CSF-VDRL, CSF-RPR, CSF-RPR-V, and CSF-TRUST among patients with symptomatic and asymptomatic neurosyphilis who had reactive CSF-
Treponema pallidum
particle agglutination (TPPA) test results. Overall, the CSF-VDRL test was reactive in 261 patients (23.1%). There were no cases in which the CSF-VDRL was nonreactive and CSF-RPR, CSF-RPR-V, or CSF-TRUST was reactive. Agreement between the results of CSF-TRUST and CSF-RPR was almost perfect (κ = 0.861), with substantial agreement between the results of CSF-RPR and CSF-RPR-V (κ = 0.740). The sensitivities of CSF-VDRL, CSF-RPR, CSF-RPR-V, and CSF-TRUST were 81.4%, 76.2%, 79.5%, and 76.2%, respectively. Compared to CSF-VDRL, CSF-RPR, CSF-RPR-V, and CSF-TRUST had comparable PPVs and NPVs. However, the specificity of CSF-VDRL (90.3%) was significantly lower than those of the other tests (92.7 to 93.4%). Therefore, CSF-RPR, CSF-RPR-V, and CSF-TRUST can be considered alternative tests for neurosyphilis diagnosis in HIV-negative populations, particularly when the CSF-VDRL is not available.
A Cost-Effective Approach for Detection of Toxigenic Clostridium difficile: Toxigenic Culture Using ChromID Clostridium difficile Agar
Authors: Luk Shik , To Wing Kin , Ng Tak Keung , Hui Wai Ting , Lee Wing Keung , Lau Florence , Ching Almond Man Wai
Published: December 2013

We evaluated the performance and the cost of toxigenic culture using a commercial chromogenic medium (CDIF) for 538 stool specimens. Compared with real-time PCR, this method was found to detect an additional 9% of positive specimens and result in 61% reduction in material costs, with a trade-off increase in turnaround time of 1 day.
Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 4 (vIRF4) Targets Expression of Cellular IRF4 and the Myc Gene To Facilitate Lytic Replication
Authors: Lee Hye-Ra , Doğanay Sultan , Chung Brian , Toth Zsolt , Brulois Kevin , Lee Stacy , Kanketayeva Zhansaya , Feng Pinghui , Ha Taekjip , Jung Jae U.
Published: December 2013

Besides an essential transcriptional factor for B cell development and function, cellular interferon regulatory factor 4 (c-IRF4) directly regulates expression of the c-
Myc
gene, which is not only associated with various B cell lymphomas but also required for herpesvirus latency and pathogenesis. Kaposi's sarcoma-associated herpesvirus (KSHV), the etiological agent of Kaposi's sarcoma and primary effusion lymphoma, has developed a unique mechanism to deregulate host antiviral innate immunity and growth control by incorporating four viral homologs (vIRF1 to -4) of cellular IRFs into its genome. Previous studies have shown that several KSHV latent proteins, including vIRF3, vFLIP, and LANA, target the expression, function, and stability of c-Myc to establish and maintain viral latency. Here we report that the KSHV vIRF4 lytic protein robustly suppresses expression of c-
IRF4
and c-
Myc
, reshaping host gene expression profiles to facilitate viral lytic replication. Genomewide gene expression analysis revealed that KSHV vIRF4 grossly affects host gene expression by upregulating and downregulating 118 genes and 166 genes, respectively, by at least 2-fold. Remarkably, vIRF4 suppressed c-
Myc
expression by 11-fold, which was directed primarily by the deregulation of c-
IRF4
expression. Real-time quantitative PCR (RT-qPCR), single-molecule
in situ
hybridization, and chromatin immunoprecipitation assays showed that vIRF4 not only reduces c-
IRF4
expression but also competes with c-IRF4 for binding to the specific promoter region of the c-
Myc
gene, resulting in drastic suppression of c-
Myc
expression. Consequently, the loss of vIRF4 function in the suppression of c-
IRF4
and c-
Myc
expression ultimately led to a reduction of KSHV lytic replication capacity. These results indicate that the KSHV vIRF4 lytic protein comprehensively targets the expression and function of c-IRF4 to downregulate c-
Myc
expression, generating a favorable environment for viral lytic replication. Finally, this study further reinforces the important role of the c-
Myc
gene in KSHV lytic replication and latency.
Enhanced Fusion and Virion Incorporation for HIV-1 Subtype C Envelope Glycoproteins with Compact V1/V2 Domains
Authors: Cavrois Marielle , Neidleman Jason , Santiago Mario L. , Derdeyn Cynthia A. , Hunter Eric , Greene Warner C.
Published: December 2013

In infected people, the HIV-1 envelope glycoprotein (Env) constantly evolves to escape the immune response while retaining the essential elements needed to mediate viral entry into target cells. The extensive genetic variation of Env is particularly striking in the V1/V2 hypervariable domains. In this study, we investigated the trade-off, in terms of fusion efficiency, for encoding V1/V2 domains of different lengths. We found that natural variations in V1/V2 length exert a profound impact on HIV-1 entry. Variants encoding compact V1/V2 domains mediated fusion with higher efficiencies than related Envs encoding longer V1/V2 domains. By exchanging the V1/V2 domains between Envs of the same infected person or between two persons linked by a transmission event, we further demonstrated that V1/V2 domains critically influence both Env incorporation into viral particles and fusion to primary CD4 T cells and monocyte-derived dendritic cells. Shortening the V1/V2 domains consistently increased Env incorporation and fusion, whereas lengthening the V1/V2 domains decreased Env incorporation and fusion. Given that in a new host transmitted founder viruses are distinguished by compact Envs with fewer glycosylation sites, our study points to fusion and possibly Env incorporation into virions as limiting steps for transmission of HIV-1 to a new host and suggests that the length and/or the N-glycosylation profile of the V1/V2 domain influences these early steps in the HIV life cycle.
The Kaposi's Sarcoma-Associated Herpesvirus (KSHV)-Induced 5-Lipoxygenase-Leukotriene B4 Cascade Plays Key Roles in KSHV Latency, Monocyte Recruitment, and Lipogenesis
Authors: Sharma-Walia Neelam , Chandran Karthic , Patel Kinjan , Veettil Mohanan Valiya , Marginean Alexandru
Published: December 2013

Kaposi's sarcoma-associated herpesvirus (KSHV) is etiologically associated with Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). KS lesions are characterized by endothelial cells with multiple copies of the latent KSHV episomal genome, lytic replication in a low percentage of infiltrating monocytes, and inflammatory cytokines plus growth factors. We demonstrated that KSHV utilizes inflammatory cyclooxygenase 2/prostaglandin E
2
to establish and maintain latency (Sharma-Walia, N., A. G. Paul, V. Bottero, S. Sadagopan, M. V. Veettil, N. Kerur, and B. Chandran, PLoS Pathog 6:e1000777, 2010 [doi:10.1371/journal.ppat.1000777]). Here, we evaluated the role of 5-lipoxygenase (5LO) and its chemotactic metabolite leukotriene B4 (LTB4) in KSHV biology. Abundant staining of 5LO was detected in human KS tissue sections. We observed elevated levels of 5LO and high levels of secretion of LTB4 during primary KSHV infection of endothelial cells and in PEL B cells (BCBL-1 and BC-3 cells). Blocking the 5LO/LTB4 cascade inhibited viral latent ORF73, immunomodulatory K5, viral macrophage inflammatory protein 1 (MIP-1), and viral MIP-2 gene expression, without much effect on lytic switch ORF50, immediate early lytic K8, and viral interferon-regulatory factor 2 gene expression. 5LO inhibition significantly downregulated latent viral Cyclin and latency-associated nuclear antigen 2 levels in PEL cells. 5LO/LTB4 inhibition downregulated TH2-related cytokine secretion, elevated TH1-related cytokine secretion, and reduced human monocyte recruitment, adhesion, and transendothelial migration. 5LO/LTB4 inhibition reduced fatty acid synthase (FASN) promoter activity and its expression. Since FASN, a key enzyme required in lipogenesis, is important in KSHV latency, these findings collectively suggest that 5LO/LTB4 play important roles in KSHV biology and that effective inhibition of the 5LO/LTB4 pathway could potentially be used in treatment to control KS/PEL.
Role of the Nuclease Activities Encoded by Herpes Simplex Virus 1 UL12 in Viral Replication and Neurovirulence
Authors: Fujii Hikaru , Mugitani Michio , Koyanagi Naoto , Liu Zhuoming , Tsuda Shumpei , Arii Jun , Kato Akihisa , Kawaguchi Yasushi
Published: December 2013

Enzyme-dead mutations in the herpes simplex virus 1 UL12 gene that abolished its endo- and exonuclease activities only slightly reduced viral replication in cell cultures. However, the UL12 null mutation significantly reduced viral replication, suggesting that a UL12 function(s) unrelated to its nuclease activities played a major role in viral replication. In contrast, the enzyme-dead mutations significantly reduced viral neurovirulence in mice, suggesting that UL12 nuclease activities were critical for viral pathogenesis
in vivo
.
Thromboprophylaxis only during hospitalisation in fast-track hip and knee arthroplasty, a prospective cohort study
Authors: Jørgensen Christoffer C , Jacobsen Michael K , Soeballe Kjeld , Hansen Torben B , Husted Henrik , Kjærsgaard-Andersen Per , Hansen Lars T , Laursen Mogens B , Kehlet Henrik
Published: December 2013

Objectives

International guidelines recommend thrombosis prophylaxis after total hip arthroplasty (THA) and total knee arthroplasty (TKA) for up to 35 days. However, previous studies often have hospital stays (length of stay; LOS) of 8–12 days and not considering early mobilisation, which may reduce incidence of venous thromboembolic events (VTE). We investigated the incidence of any symptomatic thromboembolic events (TEEs) with only in-hospital prophylaxis if LOS ≤5 days after fast-track THA and TKA.

Design

A prospective descriptive multicentre cohort study in fast-track THA and TKA from February 2010 to December 2011, with complete 90-day follow-up through the Danish National Patient Registry and patient files.

Setting

6 Danish high-volume centres with a similar standardised fast-track setup, including spinal anaesthesia, opioid-sparing analgesia, early mobilisation, functional discharge criteria and discharge to own home.

Participants

4924 consecutive unselected unilateral primary THA and TKAs in patients ≥18 years with no preoperative use of continuous ‘potent’ anticoagulative therapy (vitamin K antagonists).

Exposure

Prophylaxis with low-molecular-weight heparin or factor Xa-inhibitors only during hospitalisation when LOS ≤5 days.

Outcomes

Incidence of symptomatic TEE-related, VTE-related and VTE-related mortality ≤90 days postoperatively.

Results

LOS ≤5 days and thromboprophylaxis only during hospitalisation occurred in 4659 procedures (94.6% of total). Median LOS and prophylaxis duration was 2 days (IQR 2–3) with 0.84% (95% CI 0.62% to 1.15%) TEE and 0.41% (0.26% to 0.64%) VTE during 90-day follow-up. VTE consisted of five pulmonary embolisms (0.11% (0.05% to 0.25%)) and 14 deep venous thrombosis (0.30% (0.18% to 0.50%)). There were four (0.09% (0.04% to 0.23%)) surgery-related deaths, of which 1 (0.02% (0.00% to 0.12%)) was due to pulmonary embolism, and 6 (0.13% (0.06% to 0.28%)) deaths of unknown causes after discharge.

Conclusions

The low incidence of TEE and VTE suggests that in-hospital prophylaxis only, is safe in fast-track THA and TKA patients with LOS of ≤5 days. Guidelines on thromboprophylaxis may need reconsideration in fast-track elective surgery.

Trial Registration

ClinicalTrials.gov:NCT01557725
SYNCHRONIZATION CRITERIA FOR TWO BOOLEAN NETWORKS BASED ON LOGICAL CONTROL
Authors: CHEN HONGWEI , LIU YANG , LU JIANQUAN
Published: December 2013

This paper investigates the complete synchronization of two Boolean networks via logic control. Both feedback control and open-loop control are proposed to make the slave network completely synchronized with the master Boolean network. Using the algebraic state-space representation of Boolean networks, we derive several necessary and sufficient conditions for complete synchronization between two Boolean networks. Two examples are given to illustrate the obtained results.
MANAGING DYNAMIC RISKS IN GLOBAL IT PROJECTS: AGILE RISK-MANAGEMENT USING THE PRINCIPLES OF SERVICE-ORIENTED ARCHITECTURE
Authors: LEE O.-K. D. , BABY D. V.
Published: December 2013

Risk management in global information technology (IT) projects is becoming a critical area of concern for practitioners. Global IT projects usually span multiple locations involving various culturally diverse groups that use multiple standards and technologies. These multiplicities cause dynamic risks through interactions among internal (i.e., people, process, and technology) and external elements (i.e., business and natural environments) of global IT projects. This study proposes an agile risk-management framework for global IT project settings. By analyzing the dynamic interactions among multiplicities (e.g., multi-locations, multi-cultures, multi-groups, and multi-interests) embedded in the project elements, we identify the dynamic risks threatening the success of a global IT project. Adopting the principles of service-oriented architecture (SOA), we further propose a set of agile management strategies for mitigating the dynamic risks. The mitigation strategies are conceptually validated. The proposed framework will help practitioners understand the potential risks in their global IT projects and resolve their complex situations when certain types of dynamic risks arise.
COLLABORATIVE DATA STREAM MINING IN UBIQUITOUS ENVIRONMENTS USING DYNAMIC CLASSIFIER SELECTION
Authors: GOMES JOÃO BÁRTOLO , GABER MOHAMED MEDHAT , SOUSA PEDRO A. C. , MENASALVAS ERNESTINA
Published: December 2013

In ubiquitous data stream mining, different devices often aim to learn concepts that are similar to some extent. In many applications, such as spam filtering or news recommendation, the data stream underlying concept (e.g., interesting mail/news) is likely to change over time. Therefore, the resultant model must be continuously adapted to such changes. This paper presents a novel Collaborative Data Stream Mining (Coll-Stream) approach that explores the similarities in the knowledge available from other devices to improve local classification accuracy. Coll-Stream integrates the community knowledge using an ensemble method where the classifiers are selected and weighted based on their local accuracy for different partitions of the feature space. We evaluate Coll-Stream classification accuracy in situations with concept drift, noise, partition granularity and concept similarity in relation to the local underlying concept. The experimental results show that Coll-Stream resultant model achieves stability and accuracy in a variety of situations using both synthetic and real-world datasets.
MANAGING UNCERTAINTY AND AMBIGUITY IN GATES: DECISION MAKING IN AEROSPACE PRODUCT DEVELOPMENT
Authors: JOHANSSON CHRISTIAN
Published: December 2013

This paper investigates decision making in the stage-gate process used by an aerospace manufacturer. More specifically, it focuses on the way decision makers deal with uncertainties and ambiguities when making decisions. The stage-gate model was found to be a discussion trigger — a boundary negotiating artefact — through which stakeholders bring issues to the table, reflect on uncertainties, and decide in what areas more knowledge is needed. Managers should be aware that the knowledge base might not always be perfect and should make use of the sensemaking capabilities of the stage-gate model and the gate meeting to mitigate and improve the knowledge base. This paper elaborates on formalized knowledge-based criteria so as to support this evaluation of the knowledge base.
Probing the mechanisms underlying the mitigation of cognitive aging with anodal transcranial direct current stimulation
Authors: Kar Kohitij , Wright Jessica
Published: December 2013

Meinzer et al. ( J Neurosci 33: 12470–12478, 2013) have recently reported that anodal transcranial direct current stimulation (atDCS) mitigates age-related cognitive changes. Simultaneous measurement of BOLD signal during atDCS also showed “youth-like” processing in an elderly population. Although the effects are very promising, the underlying mechanisms of atDCS are still not clear. In this article, we provide a critical review of the results, emphasizing the article's significance and providing additional insight that will help elucidate the results and atDCS mechanisms.
Genes Related to Mitochondrial Functions, Protein Degradation, and Chromatin Folding Are Differentially Expressed in Lymphomonocytes of Rett Syndrome Patients
Authors: Pecorelli Alessandra , Leoni Guido , Cervellati Franco , Canali Raffaella , Signorini Cinzia , Leoncini Silvia , Cortelazzo Alessio , De Felice Claudio , Ciccoli Lucia , Hayek Joussef , Valacchi Giuseppe
Published: December 2013

Rett syndrome (RTT) is mainly caused by mutations in the X-linked methyl-CpG binding protein (MeCP2) gene. By binding to methylated promoters on CpG islands, MeCP2 protein is able to modulate several genes and important cellular pathways. Therefore, mutations inMeCP2can seriously affect the cellular phenotype. Today, the pathways thatMeCP2mutations are able to affect in RTT are not clear yet. The aim of our study was to investigate the gene expression profiles in peripheral blood lymphomonocytes (PBMC) isolated from RTT patients to try to evidence new genes and new pathways that are involved in RTT pathophysiology. LIMMA (Linear Models for MicroArray) and SAM (Significance Analysis of Microarrays) analyses on microarray data from 12 RTT patients and 7 control subjects identified 482 genes modulated in RTT, of which 430 were upregulated and 52 were downregulated. Functional clustering of a total of 146 genes in RTT identified key biological pathways related to mitochondrial function and organization, cellular ubiquitination and proteosome degradation, RNA processing, and chromatin folding. Our microarray data reveal an overexpression of genes involved in ATP synthesis suggesting altered energy requirement that parallels with increased activities of protein degradation. In conclusion, these findings suggest that mitochondrial-ATP-proteasome functions are likely to be involved in RTT clinical features.
Control of DFIG Wind Turbines Based on Indirect Matrix Converters in Short Circuit Mode to Improve the LVRT Capability
Authors: Khajeh Ahmad , Ghazi Reza
Published: December 2013

Nowadays, the doubly-fed induction generators (DFIGs) based wind turbines (WTs) are the dominant type of WTs. Traditionally, the back-to-back converters are used to excite the rotor circuit of DFIG. In this paper, an indirect matrix converter (IMC) is proposed to control the generator. Compared with back-to-back converters, IMCs have numerous advantages such as higher level of robustness, reliability, and reduced size and weight due to the absence of bulky electrolytic capacitor. According to the recent grid codes wind turbines must have low voltage ride-through (LVRT) capability. In this paper a new crowbar system is proposed so that along with the control system it protects the IMC from large fault currents and supports the grid voltage dips during grid faults. This crowbar system is provided using the existing converter switches to establish a short circuit mode without any extra circuitry. Even in severe fault conditions, the duration of short circuit mode is quite small so the control system will be activated shortly after the fault to inject reactive power as required by new LVRT standards. Therefore, the new LVRT standards are well satisfied without any extra costs. PSIM simulation results confirm the efficiency of the proposed method.
Moment Equations in Modeling a Stable Foreign Currency Exchange Market in Conditions of Uncertainty
Authors: Diblík Josef , Dzhalladova Irada , Michalková Mária , Růžičková Miroslava
Published: December 2013

The paper develops a mathematical model of foreign currency exchange market in the form of a stochastic linear differential equation with coefficients depending on a semi-Markov process. The boundaries of the domain of its instability is determined by using moment equations.
Analysis of Structures, Functions, and Epitopes of Cysteine Protease fromSpirometra erinaceieuropaeiSpargana
Authors: Liu Li Na , Cui Jing , Zhang Xi , Wei Tong , Jiang Peng , Wang Zhong Quan
Published: December 2013

Spirometra erinaceieuropaeicysteine protease (SeCP) in sparganum ES proteins recognized by early infection sera was identified by MALDI-TOF/TOF-MS. The aim of this study was to predict the structures and functions of SeCP protein by using the full length cDNA sequence of SeCP gene with online sites and software programs. The SeCP gene sequence was of 1 053 bp length with a 1011 bp biggest ORF encoding 336-amino acid protein with a complete cathepsin propeptide inhibitor domain and a peptidase C1A conserved domain. The predicted molecular weight and isoelectric point of SeCP were 37.87 kDa and 6.47, respectively. The SeCP has a signal peptide site and no transmembrane domain, located outside the membrane. The secondary structure of SeCP contained 8α-helixes, 7β-strands, and 20 coils. The SeCP had 15 potential antigenic epitopes and 19 HLA-I restricted epitopes. Based on the phylogenetic analysis of SeCP,S. erinaceieuropaeihas the closest evolutionary status withS. mansonoides. SeCP was a kind of proteolytic enzyme with a variety of biological functions and its antigenic epitopes could provide important insights on the diagnostic antigens and target molecular of antisparganum drugs.
All Phase Resetting Curves Are Bimodal, but Some Are More Bimodal Than Others
Authors: Oprisan Sorinel A.
Published: December 2013

Phase resetting curves (PRCs) are phenomenological and quantitative tools that tabulate the transient changes in the firing period of endogenous neural oscillators as a result of external stimuli, for example, presynaptic inputs. A brief current perturbation can produce either a delay (positive phase resetting) or an advance (negative phase resetting) of the subsequent spike, depending on the timing of the stimulus. We showed that any planar neural oscillator has two remarkable points, which we called neutral points, where brief current perturbations produce no phase resetting and where the PRC flips its sign. Since there are only two neutral points, all PRCs of planar neural oscillators are bimodal. The degree of bimodality of a PRC, that is, the ratio between
the amplitudes of the delay and advance lobes of a PRC, can be smoothly adjusted when the bifurcation scenario leading to stable oscillatory behavior combines a saddle node of invariant circle (SNIC) and an Andronov-Hopf bifurcation (HB).
Wavelet Optimal Estimations for Density Functions under Severely Ill-Posed Noises
Authors: Li Rui , Liu Youming
Published: December 2013

Motivated by Lounici and Nickl's work (2011), this paper considers the problem of estimation of a densityfbased on an independent and identically distributed sampleY1,…,Ynfromg=f*φ. We show a wavelet optimal estimation for a density (function) over Besov ballBr,qs(L)andLprisk (1≤p<∞) in the presence of severely ill-posed noises. A wavelet linear estimation is firstly presented. Then, we prove a lower bound, which shows our wavelet estimator optimal. In other words, nonlinear wavelet estimations are not needed in that case. It turns out that our results extend some theorems of Pensky and Vidakovic (1999), as well as Fan and Koo (2002).
Boundedness of Solutions for a Class of Second-Order Periodic Systems
Authors: Jiang Shunjun , Ding Yan
Published: December 2013

In this paper we study the following second-order periodic system:x′′+V′(x)+p(x,t)=0,whereV(x)has a singularity. Under some assumptions on theV(x)andp(x,t)by Ortega’ small twist theorem, we obtain the existence of quasi-periodic solutions and boundedness of all the solutions.
Limits of Riemann Solutions to the Relativistic Euler Systems for Chaplygin Gas as Pressure Vanishes
Authors: Yin Gan , Song Kyungwoo
Published: December 2013

Vanishing pressure limits of Riemann solutions to relativistic Euler system for Chaplygin gas are identified and analyzed in detail. Unlike the polytropic or barotropic gas case, as the parameter decreases to a critical value, the two-shock solution converges firstly to a delta shock wave solution to the same system. It is shown that, as the parameter decreases, the strength of the delta shock increases. Then as the pressure vanishes ultimately, the solution is nothing but the delta shock wave solution to the zero pressure relativistic Euler system. Meanwhile, the two-rarefaction wave solution and the solution containing one-rarefaction wave and one-shock wave tend to the vacuum solution and the contact discontinuity solution to the zero pressure relativistic Euler system, respectively.
Broadcasting with Prediction and Selective Forwarding in Vehicular Networks
Authors: Yang Jianjun , Fei Zongming
Published: December 2013

Broadcasting in vehicular networks has attracted great interest in research community and industry. Broadcasting on disseminating information to individual vehicle beyond the transmission range is based on inter-vehicle communication systems. It is crucial to broadcast messages to other vehicles as fast as possible because the messages in vehicle communication systems are often emergency messages such as accident warning or alarm. In many current approaches, the message initiator or sender selects the node among its neighbors that is farthest away from it in the broadcasting direction and then assigns the node to rebroadcast the message once the node gets out of its range or after a particular time slot. However, this approach may select a nonoptimal candidate because it does not consider the moving status of vehicles including their moving directions and speeds. In this paper, we develop a new approach based on prediction of future velocity and selective forwarding. The current message sender selects the best candidate that will rebroadcast the message to other vehicles as fast as possible. Key to the decision making is to consider the candidates' previous moving status and predict the future moving trends of the candidates so that the message is spread out faster. In addition, this approach generates very low overhead. Simulations demonstrate that our approach significantly decreases end-to-end delay and improves message delivery ratio.
Interactive Medical Image Segmentation Using Snake and Multiscale Curve Editing
Authors: Zhou Wu , Xie Yaoqin
Published: December 2013

Image segmentation is typically applied to locate objects and boundaries, and it is an essential process that supports medical diagnosis, surgical planning, and treatments in medical applications. Generally, this process is done by clinicians manually, which may be accurate but tedious and very time consuming. To facilitate the process, numerous interactive segmentation methods have been proposed that allow the user to intervene in the process of segmentation by incorporating prior knowledge, validating results and correcting errors. The accurate segmentation results can potentially be obtained by such user-interactive process. In this work, we propose a novel framework of interactive medical image segmentation for clinical applications, which combines digital curves and the active contour model to obtain promising results. It allows clinicians to quickly revise or improve contours by simple mouse actions. Meanwhile, the snake model becomes feasible and practical in clinical applications. Experimental results demonstrate the effectiveness of the proposed method for medical images in clinical applications.
Performance of the Priority Control Strategies for Bus Rapid Transit: Comparative Study from Scenario Microsimulation Using VISSIM
Authors: Yang Min , Wang Wei , Wang Bo , Han Jing
Published: December 2013

Bus rapid transit (BRT) has a great potential to improve the service level of transit system and has been implemented in many Chinese cities. However, the priority it can provide to buses has not been explored fully. Therefore, this study mainly investigated two advanced control strategies (signal priority using advanced detection and transit speed control). Signal priority using advanced detection is a strategy which detects one cycle ahead of buses’ arrival in order to adapt a more flexible control algorithm to provide signal priority for buses. Another is transit speed control, which provides priority at intersections for buses by controlling the speed of them and predicting their arrival at certain intersection. These two advanced strategies were modeled and evaluated using simulation software VISSIM and presented better performance than other three scenarios (base case, exclusive bus lane, and conventional transit signal priority). Only the eastbound direction would be researched as its traffic flow and bus volume are much larger than those of the other direction. Data used in this model was collected in Yingtan City. It is also shown that both the operation of BRT and the efficiency of private traffic can be much improved by applying the two strategies proposed above.