bluuebunny/crossref_metadata_2025_split huggingface dataset:
Residual Stresses in Alloy 182 PWHT Buttering and Attachment Weld: Validation by Modeling and Measurements of a Full Scale Mockup
Authors: Bremberg Daniel , Gunnars Jens , Bonnaud Etienne , Edling Lars-Olof , Kingston Ed 
Published: November 2014

Internal components in nuclear reactor pressure vessels are joined to the ferritic vessel by use of dissimilar metal welds which commonly include nickel base weld material Alloy 182. It has turned out that Alloy 182 sometimes is susceptible to stress corrosion cracking (SCC) for the operating environment in reactors. Tensile residual stress has a large influence on SCC and it is important to carefully characterize the residual stresses generated at manufacturing. The manufacturing of these welds includes welding Alloy 182 to the ferritic steel to form a buttering, post-weld heat treatment (PWHT) of the buttering, and finally attachment welding between the internal component and the buttering.
An experimental program was designed for measurement and numerical analysis for validation of residual stresses in a nickel base Alloy 182 weld between the core shroud support leg and reactor pressure vessel. Two full-scale mock-ups were manufactured according to the original procedures for the buttering to the ferritic steel and the final attachment weld to the core shroud support. The mock-up was also carefully designed to produce correct boundary conditions for the support leg. Measurements were performed by the deep-hole drilling technique (DHD/iDHD). The residual stress fields from welding and heat treatments were predicted by detailed numerical modelling. Comparison between the numerical results and the measurement results shows very good agreement and validates the predicted residual stresses. It was concluded that the PWHT of the vessel only partly relieve weld residual stresses in the nickel base buttering.
Development of an Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities: Part 6 — Scaled Tests to Obtain Basic Characteristics of Lead Rubber Bearing
Authors: Hirotani Tsutomu , Takahama Ryota , Yukawa Masaki , Hibino Hiroshi , Aikawa Yuji , Hirai Hideo , Imaoka Tetsuo , Shimizu Hiroshi , Umeki Yoshito 
Published: November 2014

This paper provides a series comprising the “Development of Evaluation Method for Seismic Isolation Systems of Nuclear Power Facilities”. Part 6 presents scaled tests for Lead Rubber Bearing (LRB) newly developed for this project.
Following tests are performed to obtain the basic characteristics of LRB,.
(1) Horizontal and Vertical Simultaneous Loading Test:
LRBs with diameter of 250mm are tested dynamically under simultaneous axial and lateral loading. The hysteresis characteristics is not changed under compressive load although it is changed under tensile load.
(2) Basic Break Test:
LRBs with a diameter of 800mm are tested statically under various combinations of axial and lateral forces. The hysteresis characteristics model of LRB is determined by this test. It is confirmed that the breaking strain of LRB under compression load exceeds 450%.
(3) Horizontal Hardening and Vertical Softening Test:
For LRBs with a diameter of 1200 mm, 75% scale of actual LRB are tested statically for horizontal hardening and vertical softening regions. It is confirmed that the hysteresis model which is developed by smaller LRBs is applicable to these large scale models.
Optimal Make-Up Torque for Trapezoidal Threaded Connections Subjected to Combined Axial Tension and Internal Pressure Loading
Authors: Galle Timothy , De Waele Wim , Van Wittenberghe Jeroen , De Baets Patrick 
Published: November 2014

When assembling tubing strings in the oilfields, threaded connections are used to connect the pipes with each other. The possibility to reuse these connections is often required and a certain degree of leak tightness is required, even without the use of a sealing surface or shoulder. For this reason, the total plasticity within the connection should be limited and relative movement between pin and box ought to be restricted.
Within this publication, a finite elements analysis is conducted using a 4.5 inch buttress threaded connection as defined in API 5B together with a connection using the enhanced SR23 buttress thread. In addition, an experimental validation of the make-up stage is conducted by comparing the strains generated during make-up using Digital Image Correlation and infrared monitoring.
In order to determine the optimal make-up, values found in literature are compared with a developed method using the magnitude and size of the plastically deformed zones during make-up. In addition, the effect of external axial and pressure loading is examined to identify the effects and critical areas.
As a result, it is observed that pressure loading and make-up tend to have similar effects and in order to determine the optimal make-up torque, the pressure ratings of the assembly should be taken into account to prevent overtorqueing the connection. For the case of axial loading, a critical zone is visible near the last engaged thread and excessive loading of this thread can cause premature failure within this zone. Overall, the SR23 connection shows limited, yet visible, advantages over the standard BTC connection as described in literature.
Evaluation of a Weld Overlay Design for a Bimetallic Weld Using the Failure Assessment Diagram
Authors: Heldt Jens , Lohse Christopher , Cofie Nathaniel G. , Lashley Michael 
Published: November 2014

During routine inspection of an N5 feedwater nozzle dissimilar metal weld (DMW) of a BWR, an axial flaw was detected in the weld. The flaw was mitigated by applying a full structural weld overlay (WOL) repair consisting of Alloy 52M weld metal and using the gas tungsten arc welding process (GTAW). Because of the ductile nature and very high toughness of the Alloy 52M material, the limit load approach of ASME Code, Section XI, Appendix C was used for the sizing of the overlay. The use of limit load for the design of weld overlays for Alloy 52M material is supported by several studies documented in the industry [1].
In order to address other fracture failure modes such as failure by ductile tearing and brittle fracture, a failure assessment diagram (FAD) approach was used to evaluate the acceptability of the weld overlay design. FADs have been used for evaluating flaws in piping components, but not for acceptance of flaws in WOLs. The FAD evaluation was performed in accordance with the ASME Code, Section XI, Appendix H requirements which address brittle fracture, elastic-plastic fracture mechanics (ductile tearing), and limit load failure modes. The applicable stress combinations were used in combination with the materials JR resistance curve to determine flaw acceptability at the end of the evaluation period.
The evaluation considered the presence of both a circumferential flaw (360° around the circumference and 100% through the original pipe wall; the design basis for the full structural weld overlay) and an axial flaw. For both circumferential and axial flaws, several assessment points corresponding to the JR resistance curve were determined and plotted on the FAD curve for austenitic steels in ASME Section XI, Appendix H. The FAD curve in Appendix H was derived based on strength properties of stainless steel and is considered conservative in application to Alloy 52M since Alloy 52M has higher strength. All the assessment points were found to be below the FAD curve thus indicating the acceptability of the weld overlay with consideration to all the three possible fracture regimes.
Pharmacodynamics of Imipenem in Combination with β-Lactamase Inhibitor MK7655 in a Murine Thigh Model
Authors: Mavridou Eleftheria , Melchers Ria J. B. , van Mil Anita C. H. A. M. , Mangin E. , Motyl Mary R. , Mouton Johan W. 
Published: November 2014

ABSTRACT

MK7655 is a newly developed beta-lactamase inhibitor of class A and class C carbapenemases. Pharmacokinetics (PK) of imipenem-cilastatin (IMP/C) and MK7655 were determined for intraperitoneal doses of 4 mg/kg to 128 mg/kg of body weight. MIC and pharmacodynamics (PD) studies of MK7655 were performed against several beta-lactamase producing
Pseudomonas aeruginosa
and
Klebsiella pneumoniae
strains to determine its effect
in vitro
and
in vivo
. Neutropenic mice were infected in each thigh 2 h before treatment with an inoculum of approximately 5 × 10
6
CFU. They were treated with IMP/C alone (every 2 hours [q2h], various doses) or in combination with MK7655 in either a dose fractionation study or q2h for 24 h and sacrificed for CFU determinations. IMP/MK7655 decreased MICs regarding IMP MIC. The PK profiles of IMP/C and MK7655 were linear over the dosing range studied and comparable with volumes of distribution (
V
) of 0.434 and 0.544 liter/kg and half-lives (
t
1/2
) of 0.24 and 0.25 h, respectively. Protein binding of MK7655 was 20%. A sigmoidal maximum effect (
E
max
) model was fit to the PK/PD index responses. The effect of the inhibitor was not related to the maximum concentration of drug in serum (
C
max
)/MIC, and model fits for
T
>MIC
and area under the concentration-time curve (AUC)/MIC were comparable (
R
2
of 0.7 and 0.75), but there appeared to be no significant relationship of effect with dose frequency. Escalating doses of MK7655 and IMP/C showed that the AUC of MK7655 required for a static effect was dependent on the dose of IMP/C and the MIC of the strain, with a mean area under the concentration-time curve for the free, unbound fraction of the drug (
f
AUC) of 26.0 mg · h/liter. MK7655 shows significant activity
in vivo
and results in efficacy of IMP/C in otherwise resistant strains. The exposure-response relationships found can serve as a basis for establishing dosing regimens in humans.
Prophylaxis with Teicoplanin and Cefuroxime Reduces the Rate of Prosthetic Joint Infection after Primary Arthroplasty
Authors: Tornero Eduard , García-Ramiro Sebastian , Martínez-Pastor Juan C. , Bori Guillem , Bosch Jordi , Morata Laura , Sala Marta , Basora Misericordia , Mensa Josep , Soriano Alex 
Published: November 2014

ABSTRACT

The aim of this study was to compare the prosthetic joint infection (PJI) rate after total joint arthroplasty in two consecutive periods of treatment with different antibiotic prophylaxes: cefuroxime versus cefuroxime plus teicoplanin. We retrospectively reviewed 1,896 patients who underwent total hip arthroplasty or total knee arthroplasty between March 2010 and February 2013. From March 2010 to August 2011, patients received 1.5 g of cefuroxime during induction of anesthesia and another 1.5 g 2 h later (the C group). From September 2011, 800 mg of teicoplanin was added to cefuroxime (the CT group). Throughout the period studied, there were no variations in pre- or postoperative protocols. Univariate and multivariate analyses were performed to evaluate independent predictors of PJI. There were 995 (55.7%) patients in the C group and 791 (44.3%) in the CT group. Patients in the CT group had a significantly lower PJI rate than patients in the C group (1.26% versus 3.51%,
P
= 0.002). There were no infections due to
Staphylococcus aureus
in the CT group (0% versus 1.6% in the C group,
P
< 0.001). A stepwise forward Cox regression model identified male sex (hazard ratio [HR], 3.85; 95% confidence interval [CI], 2.09 to 7.18), a body mass index of ≥35 kg/m
2
(HR, 2.93; 95% CI, 1.37 to 6.27), the presence of lung disease (HR, 2.46; 95% CI, 1.17 to 5.15), and red blood cell transfusion (HR, 3.70; 95% CI, 1.89 to 7.23) to be independent variables associated with a higher risk of PJI. The addition of teicoplanin was associated with a lower risk of infection (HR, 0.35; 95% CI, 0.17 to 0.74). In conclusion, the addition of teicoplanin to cefuroxime during primary arthroplasty was associated with a significant reduction in the global PJI rate due to a reduction of infections caused by Gram-positive bacteria.
Novel Strategy for Biofilm Inhibition by Using Small Molecules Targeting Molecular Chaperone DnaK
Authors: Arita-Morioka Ken-ichi , Yamanaka Kunitoshi , Mizunoe Yoshimitsu , Ogura Teru , Sugimoto Shinya 
Published: November 2014

ABSTRACT

Biofilms are complex communities of microorganisms that attach to surfaces and are embedded in a self-produced extracellular matrix. Since these cells acquire increased tolerance against antimicrobial agents and host immune systems, biofilm-associated infectious diseases tend to become chronic. We show here that the molecular chaperone DnaK is important for biofilm formation and that chemical inhibition of DnaK cellular functions is effective in preventing biofilm development. Genetic, microbial, and microscopic analyses revealed that deletion of the
dnaK
gene markedly reduced the production of the extracellular functional amyloid curli, which contributes to the robustness of
Escherichia coli
biofilms. We tested the ability of DnaK inhibitors myricetin (Myr), telmisartan, pancuronium bromide, and zafirlukast to prevent biofilm formation of
E. coli
. Only Myr, a flavonol widely distributed in plants, inhibited biofilm formation in a concentration-dependent manner (50% inhibitory concentration [IC
50
] = 46.2 μM); however, it did not affect growth. Transmission electron microscopy demonstrated that Myr inhibited the production of curli. Phenotypic analyses of thermosensitivity, cell division, intracellular level of RNA polymerase sigma factor RpoH, and vulnerability to vancomycin revealed that Myr altered the phenotype of
E. coli
wild-type cells to make them resemble those of the isogenic
dnaK
deletion mutant, indicating that Myr inhibits cellular functions of DnaK. These findings provide insights into the significance of DnaK in curli-dependent biofilm formation and indicate that DnaK is an ideal target for antibiofilm drugs.
Critical Roles of Clostridium difficile Toxin B Enzymatic Activities in Pathogenesis
Authors: Li Shan , Shi Lianfa , Yang Zhiyong , Zhang Yongrong , Perez-Cordon Gregorio , Huang Tuxiong , Ramsey Jeremy , Oezguen Numan , Savidge Tor C. , Feng Hanping 
Published: November 2014

ABSTRACT

TcdB is one of the key virulence factors of
Clostridium difficile
that is responsible for causing serious and potentially fatal colitis. The toxin contains at least two enzymatic domains: an effector glucosyltransferase domain for inactivating host Rho GTPases and a cysteine protease domain for the delivery of the effector domain into host cytosol. Here, we describe a novel intrabody approach to examine the role of these enzymes of TcdB in cellular intoxication. By screening a single-domain heavy chain (V
H
H) library raised against TcdB, we identified two V
H
H antibodies, 7F and E3, that specifically inhibit TcdB cysteine protease and glucosyltransferase activities, respectively. Cytoplasmic expression of 7F intrabody in Vero cells inhibited TcdB autoprocessing and delayed cellular intoxication, whereas E3 intrabody completely blocked the cytopathic effects of TcdB holotoxin. These data also demonstrate for the first time that toxin autoprocessing occurs after cysteine protease and glucosyltransferase domains translocate into the cytosol of target cells. We further determined the role of the enzymatic activities of TcdB in
in vivo
toxicity using a sensitive systemic challenge model in mice. Consistent with these
in vitro
results, a cysteine protease noncleavable mutant, TcdB-L543A, delayed toxicity in mice, whereas glycosyltransferase-deficient TcdB demonstrated no toxicity up to 500-fold of the 50% lethal dose (LD
50
) when it was injected systemically. Thus, glucosyltransferase but not cysteine protease activity is critical for TcdB-mediated cytopathic effects and TcdB systemic toxicity, highlighting the importance of targeting toxin glucosyltransferase activity for future therapy.
Myeloid-Derived Suppressor Cells Impair Alveolar Macrophages through PD-1 Receptor Ligation during Pneumocystis Pneumonia
Authors: Lei Guang-Sheng , Zhang Chen , Lee Chao-Hung 
Published: November 2014

ABSTRACT

Myeloid-derived suppressor cells (MDSCs) were recently found to accumulate in the lungs during
Pneumocystis
pneumonia (PcP). Adoptive transfer of these cells caused lung damage in recipient mice, suggesting that MDSC accumulation is a mechanism of pathogenesis in PcP. In this study, the phagocytic activity of alveolar macrophages (AMs) was found to decrease by 40% when they were incubated with MDSCs from
Pneumocystis
-infected mice compared to those incubated with Gr-1
+
cells from the bone marrow of uninfected mice. The expression of the PU.1 gene in AMs incubated with MDSCs also was decreased. This PU.1 downregulation was due mainly to decreased histone 3 acetylation and increased DNA methylation caused by MDSCs. MDSCs were found to express high levels of PD-L1, and alveolar macrophages (AMs) were found to express high levels of PD-1 during PcP. Furthermore, PD-1 expression in AMs from uninfected mice was increased by 18-fold when they were incubated with MDSCs compared to those incubated with Gr-1
+
cells from the bone marrow of uninfected mice. The adverse effects of MDSCs on AMs were diminished when the MDSCs were pretreated with anti-PD-L1 antibody, suggesting that MDSCs disable AMs through PD-1/PD-L1 ligation during PcP.
bis
-Molybdopterin Guanine Dinucleotide Is Required for Persistence of Mycobacterium tuberculosis in Guinea Pigs
Authors: Williams Monique J. , Shanley Crystal A. , Zilavy Andrew , Peixoto Blas , Manca Claudia , Kaplan Gilla , Orme Ian M. , Mizrahi Valerie , Kana Bavesh D. 
Published: November 2014

ABSTRACT

Mycobacterium tuberculosis
is able to synthesize molybdopterin cofactor (MoCo), which is utilized by numerous enzymes that catalyze redox reactions in carbon, nitrogen, and sulfur metabolism. In bacteria, MoCo is further modified through the activity of a guanylyltransferase, MobA, which converts MoCo to
bis
-molybdopterin guanine dinucleotide (
bis
-MGD), a form of the cofactor that is required by the dimethylsulfoxide (DMSO) reductase family of enzymes, which includes the nitrate reductase NarGHI. In this study, the functionality of the
mobA
homolog in
M. tuberculosis
was confirmed by demonstrating the loss of assimilatory and respiratory nitrate reductase activity in a
mobA
deletion mutant. This mutant displayed no survival defects in human monocytes or mouse lungs but failed to persist in the lungs of guinea pigs. These results implicate one or more
bis
-MGD-dependent enzymes in the persistence of
M. tuberculosis
in guinea pig lungs and underscore the applicability of this animal model for assessing the role of molybdoenzymes in this pathogen.
A Salmonella Type Three Secretion Effector/Chaperone Complex Adopts a Hexameric Ring-Like Structure
Authors: Roblin Pierre , Dewitte Frédérique , Villeret Vincent , Biondi Emanuele G. , Bompard Coralie 
Published: November 2014

ABSTRACT

Many bacterial pathogens use type three secretion systems (T3SS) to inject virulence factors, named effectors, directly into the cytoplasm of target eukaryotic cells. Most of the T3SS components are conserved among plant and animal pathogens, suggesting a common mechanism of recognition and secretion of effectors. However, no common motif has yet been identified for effectors allowing T3SS recognition. In this work, we performed a biochemical and structural characterization of the
Salmonella
SopB/SigE chaperone/effector complex by small-angle X-ray scattering (SAXS). Our results showed that the SopB/SigE complex is assembled in dynamic homohexameric-ring-shaped structures with an internal tunnel. In this ring, the chaperone maintains a disordered N-terminal end of SopB molecules, in a good position to be reached and processed by the T3SS. This ring dimensionally fits the ring-organized molecules of the injectisome, including ATPase hexameric rings; this organization suggests that this structural feature is important for ATPase recognition by T3SS. Our work constitutes the first evidence of the oligomerization of an effector, analogous to the organization of the secretion machinery, obtained in solution. As effectors share neither sequence nor structural identity, the quaternary oligomeric structure could constitute a strategy evolved to promote the specificity and efficiency of T3SS recognition.
A Scheduling Framework for Spatial Architectures Across Multiple Constraint-Solving Theories
Authors: Nowatzki Tony , Sartin-Tarm Michael , De Carli Lorenzo , Sankaralingam Karthikeyan , Estan Cristian , Robatmili Behnam 
Published: November 2014

Spatial architectures provide energy-efficient computation but require effective scheduling algorithms. Existing heuristic-based approaches offer low compiler/architect productivity, little optimality insight, and low architectural portability.
We seek to develop a spatial-scheduling framework by utilizing constraint-solving theories and find that architecture primitives and scheduler responsibilities can be related through five abstractions: computation placement, data routing, event timing, resource utilization, and the optimization objective. We encode these responsibilities as 20 mathematical constraints, using SMT and ILP, and create schedulers for the TRIPS, DySER, and PLUG architectures. Our results show that a general declarative approach using constraint solving is implementable, is practical, and can outperform specialized schedulers.
EXIP
Authors: Kyusakov Rumen , Pereira Pablo Puñal , Eliasson Jens , Delsing Jerker 
Published: November 2014

Developing and deploying Web applications on networked embedded devices is often seen as a way to reduce the development cost and time to market for new target platforms. However, the size of the messages and the processing requirements of today's Web protocols, such as HTTP and XML, are challenging for the most resource-constrained class of devices that could also benefit from Web connectivity.
New Web protocols using binary representations have been proposed for addressing this issue. Constrained Application Protocol (CoAP) reduces the bandwidth and processing requirements compared to HTTP while preserving the core concepts of the Web architecture. Similarly, Efficient XML Interchange (EXI) format has been standardized for reducing the size and processing time for XML structured information. Nevertheless, the adoption of these technologies is lagging behind due to lack of support from Web browsers and current Web development toolkits.
Motivated by these problems, this article presents the design and implementation techniques for the EXIP framework for embedded Web development. The framework consists of a highly efficient EXI processor, a tool for EXI data binding based on templates, and a CoAP/EXI/XHTML Web page engine. A prototype implementation of the EXI processor is herein presented and evaluated. It can be applied to Web browsers or thin server platforms using XHTML and Web services for supporting human-machine interactions in the Internet of Things.
This article contains four major results: (1) theoretical and practical evaluation of the use of binary protocols for embedded Web programming; (2) a novel method for generation of EXI grammars based on XML Schema definitions; (3) an algorithm for grammar concatenation that produces normalized EXI grammars directly, and hence reduces the number of iterations during grammar generation; (4) an algorithm for efficient representation of possible deviations from the XML schema.