bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Transfer Enhancement for Heat Exchanger Applications: Use of Surface Hydrophobicity
Authors: Kafarakis S. T. , Mastrokalos M. E. , Papadopoulos C. I. , Kaiktsis L. 
Published: December 2016

Hydrophobic surfaces, enabling flow slip past a solid boundary, can potentially be effective for heat transfer enhancement in heat exchanger applications. The scope of the present work is the computational study of forced convection heat transfer in flow past a hydrophobic cylinder, maintained at constant surface temperature. Hydrophobic surfaces are applied in flow control applications, since they enable flow slip past a solid boundary; as a result, they can contribute to flow stabilization. At the same time, hydrophobic surfaces are a potential means for heat transfer enhancement. In the present study, a computational investigation of forced convection heat transfer in cross-flow past a circular hydrophobic cylinder is performed by means of Computational Fluid Dynamics; the effects of hydrophobicity on flow stability and forces are also quantified. Here, low Reynolds number values, Re, are considered, whereas the Prandtl number, Pr, is maintained constant, equal to unity. Hydrophobicity is modelled by means of the Navier model.
For slip conditions applied on the entire cylinder surface, the present results demonstrate that the stabilizing effect of increasing the non-dimensional slip length, b* = b/D, b being the slip length and D the cylinder diameter, is accompanied by a simultaneous enhancement of heat transfer. In particular, the time-averaged mean Nusselt number, Num, is found to be an increasing function of both b* and Re. Further, it is shown that, for the same levels of b*, an equivalent heat transfer rate can be achieved by substantially reducing the extent of the hydrophobic region, in particular by excluding the rear stagnation point region, i.e. at a significantly reduced cost. Overall, the present results illustrate that implementing partial hydrophobicity results in a substantial enhancement of heat transfer rates and a simultaneous (partial or full) suppression of the wake unsteadiness.
Yield Strength Reduction Factor of Nonlinear SDOF Systems on the Supporting Structures
Authors: Tamura Ichiro , Matsuura Shinichi , Shimazu Ryuya 
Published: December 2016

Equipment installed on the supporting structure responds to the earthquake floor motion, which is strongly amplified by the structural response of the supporting structure. The required yield strength of equipment can be reduced by allowing inelastic deformation of the supporting structure and its equipment. Inelastic behavior of the supporting structure can significantly reduce elastic floor response spectra, especially their peak values. Furthermore, the allowance of inelastic deformation of equipment in strongly amplified spectral region produces a significant reduction in the required yield strength of equipment.
In this study, we discussed inelastic behavior of single-degree-of-freedom(SDOF) systems installed on the supporting structures by using constant-ductility floor response spectra. Constant-ductility floor response spectra readily provide the yield strength of a SDOF system necessary to limit the ductility demand imposed by an earthquake floor motion to a specified value. Based on these discussions, we propose simple and conservative equations of the yield strength reduction factor of nonlinear inelastic SDOF systems with the natural period, the ductility factor and the stiffness ratio for earthquake floor motions.
Optimal Weld Design of Plug Repair in Reactor Pressure Vessel With 3D Computational Weld Modeling
Authors: Brust Frederick W. , Barton David 
Published: December 2016

A bottom mounted instrument (BMI) nozzle in a European nuclear pressure vessel experienced some cracking caused by primary water stress corrosion cracking (PWSCC). Rather than repair the nozzle a decision was made to place a plug over the nozzle hole since this particular instrument panel could be removed in the reactor. The plug repair will be installed remotely during an outage and consists of performing the welding from a location near the top of the vessel which is more than 20 meters away. This makes the design of the repair critical.
This paper uses 3D computational weld analyses to design the repair. Considerations for the design include the possibility of repair welds, proper seating of the plug (distortion control), weld residual stress control, and load applications to the plug during the repair process. Computational weld modeling permitted a proper design to be realized and helped in the regulatory certification process for the plug repair. These are discussed in this paper.
Characteristics of Turbulence and Drag Forces on Foreign Objects in Tube Arrays
Authors: Mureithi Njuki , Cucuel Bastien , Saber-Cherif Karim , Olala Stephen , Ashrafi Farzad 
Published: December 2016

Steam generator tube wear due to foreign objects (FOs) is a significant industry problem. Removal of foreign objects comes with challenges related to accessibility and the environment inside the steam generator. It is therefore of interest to estimate the rate of wear due to foreign objects lodged within the SG; particularly in the tube-sheet region. To estimate wear, the fluid forces acting on the FO are a key input.
Much remains unknown regarding the characteristics of fluid forces acting on small objects located within tube arrays. In the work reported here, an exploratory study of fluid forces acting on complex geometry objects was done. Force measurements were conducted in a wind-tunnel on a range of objects to investigate the effect of object geometry on the drag coefficient and the parameters which may be used to develop drag coefficient correlations.
Turbulence forces acting on FOs in a tube array were found to be intimately related to turbulence forces acting on the tubes themselves. A direct relation between the corresponding force PSDs, via turbulence force correlations, is reported. This is a potentially useful result with regard to the nature of fluid forces acting on foreign objects in general.
Development of Evaluation Procedures for Crack Initiation From In-Service Flaws in CANDU Zr-2.5Nb Pressure Tubes With Hydrogen
Authors: Cho David , Xu Steven X. , Scarth Douglas A. , Shek Gordon K. 
Published: December 2016

Flaws found during in-service inspection of CANDU(1) Zr-2.5Nb pressure tubes include fuel bundle scratches, debris fretting flaws, fuel bundle bearing pad fretting flaws and crevice corrosion flaws. These flaws are volumetric and blunt in nature. Crack initiation from in-service flaws can be caused by the presence of hydrogen in operating pressure tubes and resultant formation of hydrided regions at the flaw tips during reactor heat-up and cool-down cycles. Zr-2.5Nb pressure tubes in the as-manufactured condition contain hydrogen as an impurity element. During operation, the pressure tube absorbs deuterium, which is a hydrogen isotope, from the corrosion reaction of the zirconium with the heavy water coolant. In addition, deuterium ingresses into the pressure tube in the rolled joint region. The level of hydrogen isotope in pressure tubes increases with operating time.
Over the years, Canadian CANDU industry has carried out extensive experimental and analytical programs to develop evaluation procedures for crack initiation from in-service flaws in Zr-2.5Nb pressure tubes. Crack initiation experiments were performed on pressure tube specimens with machined notches to quantify resistance to crack initiation under various simulated flaw geometries and operating conditions such as operating load and hydrogen concentration. Predictive engineering models for crack initiation have been developed based on understandings of crack initiation and experimental data. A set of technical requirements, including engineering procedures and acceptance criteria, for evaluation of crack initiation from in-service flaws in operating pressure tubes has been developed and implemented in the CSA Standard N285.8. A high level review of the development of these flaw evaluation procedures is described in this paper. Operating experience with the application of the developed flaw evaluation procedure is also provided.
Deterministic Technical Basis for Re-Examination Interval of Every Second Refueling Outage for PWR Reactor Vessel Heads Operating at Tcold With Previously Detected PWSCC
Authors: White Glenn , Fuhr Kevin , Burkardt Markus , Harrington Craig 
Published: December 2016

Plant operating experience with Alloy 600 reactor pressure vessel top head penetration nozzles in U.S. PWRs shows that the inspection intervals prescribed by ASME Code Case N-729-1 have been successful in managing the PWSCC concern. No through-wall cracking has been observed in the U.S. after the first in-service volumetric or surface examination was performed on all CRDM or CEDM nozzles in a given head. The current inspection intervals have facilitated identification of any PWSCC in its early stages, with small numbers of nozzles affected and substantial margins to leakage at the five affected heads operating at Tcold. MRP-395 demonstrated through both deterministic and probabilistic analyses that the inspection intervals of Code Case N-729-1 remain valid to conservatively address the PWSCC concern.
This paper supplements MRP-395 with additional deterministic crack growth analyses coupled with assessments of the PWSCC indications detected in heads operating at Tcold. The supplemental deterministic assessments presented in this paper demonstrate the acceptability of a 36-month volumetric or surface inspection interval for heads with previously detected PWSCC and that operate at Tcold. Until Code Case N-729-5 is approved by U.S. NRC, use of the 36-month interval in the U.S. for such heads would require review and approval by U.S. NRC of a relief request submitted by the licensee.
Respiratory Syncytial Virus: Infection, Detection, and New Options for Prevention and Treatment
Authors: Griffiths Cameron , Drews Steven J. , Marchant David J. 
Published: December 2016

SUMMARYRespiratory syncytial virus (RSV) infection is a significant cause of hospitalization of children in North America and one of the leading causes of death of infants less than 1 year of age worldwide, second only to malaria. Despite its global impact on human health, there are relatively few therapeutic options available to prevent or treat RSV infection. Paradoxically, there is a very large volume of information that is constantly being refined on RSV replication, the mechanisms of RSV-induced pathology, and community transmission. Compounding the burden of acute RSV infections is the exacerbation of preexisting chronic airway diseases and the chronic sequelae of RSV infection. A mechanistic link is even starting to emerge between asthma and those who suffer severe RSV infection early in childhood. In this article, we discuss developments in the understanding of RSV replication, pathogenesis, diagnostics, and therapeutics. We attempt to reconcile the large body of information on RSV and why after many clinical trials there is still no efficacious RSV vaccine and few therapeutics.
Multicenter Evaluation of a Modified Cefoxitin Disk Diffusion Method and PBP2a Testing To Predict
mecA
-Mediated Oxacillin Resistance in Atypical Staphylococcus aureus
Authors: Miller Shelley A. , Karichu James , Kohner Peggy , Cole Nicolynn , Hindler Janet A. , Patel Robin , Richter Sandra , Humphries Romney M. 
Published: December 2016

ABSTRACT

Phenotypic variants of
Staphylococcus aureus
that display small colonies, reduced pigmentation, and decreased hemolysis and/or coagulase activity are periodically isolated by the clinical laboratory. Antimicrobial susceptibility testing (AST) of these isolates is complicated, because many do not grow on routine AST media, including Mueller-Hinton agar (MHA) and cation-adjusted Mueller-Hinton broth. This multicenter study evaluated cefoxitin disk diffusion for 37 atypical
S. aureus
isolates (156 readings) with MHA supplemented with 5% sheep's blood (BMHA), using
mecA
PCR as the reference standard. The correlation of two commercial PBP2a assays with
mecA
PCR was also assessed. Ten isolates were negative and 27 positive for
mecA
. No major errors for cefoxitin were observed, but 19.5% very major errors (VMEs) were observed at 24 h of incubation, and 17.2% VMEs were observed at 48 h. The proportions of VMEs ranged from 14.7 to 23.0% at 24 h, and from 13.3 to 17.6% at 48 h, across three testing laboratories. PBP2a tests were performed from growth on BMHA and blood agar plates (BAP), with and without cefoxitin disk induction. The Alere PBP2a SA culture colony test sensitivities for
mecA
were 90.0% with uninduced growth and 97.4% with induced growth from BMHA. On BAP, sensitivity was 96.0% with induced growth. The sensitivities of the Oxoid PBP2′ latex agglutination test were 85.7% with uninduced growth and 93.9% with induced growth from BMHA and 95.9% with induced growth on BAP. On the basis of these data, we recommend that laboratories perform only
mecA
PCR and/or PBP2a tests when requested to perform AST on atypical isolates of
S. aureus
.
The Human Cytomegalovirus IE1 Protein Antagonizes PML Nuclear Body-Mediated Intrinsic Immunity via the Inhibition of PML
De Novo
SUMOylation
Authors: Schilling Eva-Maria , Scherer Myriam , Reuter Nina , Schweininger Johannes , Muller Yves A. , Stamminger Thomas 
Published: December 2016

ABSTRACT

PML nuclear bodies (NBs) are accumulations of cellular proteins embedded in a scaffold-like structure built by SUMO-modified PML/TRIM19. PML and other NB proteins act as cellular restriction factors against human cytomegalovirus (HCMV); however, this intrinsic defense is counteracted by the immediate early protein 1 (IE1) of HCMV. IE1 directly interacts with the PML coiled-coil domain via its globular core region and disrupts NB foci by inducing a loss of PML SUMOylation. Here, we demonstrate that IE1 acts via abrogating the
de novo
SUMOylation of PML. In order to overcome reversible SUMOylation dynamics, we made use of a cell-based assay that combines inducible IE1 expression with a SUMO mutant resistant to SUMO proteases. Interestingly, we observed that IE1 expression did not affect preSUMOylated PML; however, it clearly prevented
de novo
SUMO conjugation. Consistent results were obtained by
in vitro
SUMOylation assays, demonstrating that IE1 alone is sufficient for this effect. Furthermore, IE1 acts in a selective manner, since K160 was identified as the main target lysine. This is strengthened by the fact that IE1 also prevents As
2
O
3
-mediated hyperSUMOylation of K160, thereby blocking PML degradation. Since IE1 did not interfere with coiled-coil-mediated PML dimerization, we propose that IE1 affects PML autoSUMOylation either by directly abrogating PML E3 ligase function or by preventing access to SUMO sites. Thus, our data suggest a novel mechanism for how a viral protein counteracts a cellular restriction factor by selectively preventing the
de novo
SUMOylation at specific lysine residues without affecting global protein SUMOylation.

IMPORTANCE
The human cytomegalovirus IE1 protein acts as an important antagonist of a cellular restriction mechanism that is mediated by subnuclear structures termed PML nuclear bodies. This function of IE1 is required for efficient viral replication and thus constitutes a potential target for antiviral strategies. In this paper, we further elucidate the molecular mechanism for how IE1 antagonizes PML NBs. We show that tight binding of IE1 to PML interferes with the
de novo
SUMOylation of a distinct lysine residue that is also the target of stress-mediated hyperSUMOylation of PML. This is of importance since it represents a novel mechanism used by a viral antagonist of intrinsic immunity. Furthermore, it highlights the possibility of developing small molecules that specifically abrogate this PML-antagonistic activity of IE1 and thus inhibit viral replication.
Inhibition of an Aquatic Rhabdovirus Demonstrates Promise of a Broad-Spectrum Antiviral for Use in Aquaculture
Authors: Balmer Bethany F. , Powers Rachel L. , Zhang Ting-Hu , Lee Jihye , Vigant Frederic , Lee Benhur , Jung Michael E. , Purcell Maureen K. , Snekvik Kevin , Aguilar Hector C. 
Published: December 2016

ABSTRACT

Many enveloped viruses cause devastating disease in aquaculture, resulting in significant economic impact. LJ001 is a broad-spectrum antiviral compound that inhibits enveloped virus infections by specifically targeting phospholipids in the lipid bilayer via the production of singlet oxygen (
1
O
2
). This stabilizes positive curvature and decreases membrane fluidity, which inhibits virus-cell membrane fusion during viral entry. Based on data from previous mammalian studies and the requirement of light for the activation of LJ001, we hypothesized that LJ001 may be useful as a preventative and/or therapeutic agent for infections by enveloped viruses in aquaculture. Here, we report that LJ001 was more stable with a prolonged inhibitory half-life at relevant aquaculture temperatures (15°C), than in mammalian studies at 37°C. When LJ001 was preincubated with our model virus, infectious hematopoietic necrosis virus (IHNV), infectivity was significantly inhibited
in vitro
(using the epithelioma papulosum cyprini [EPC] fish cell line) and
in vivo
(using rainbow trout fry) in a dose-dependent and time-dependent manner. While horizontal transmission of IHNV in a static cohabitation challenge model was reduced by LJ001, transmission was not completely blocked at established antiviral doses. Therefore, LJ001 may be best suited as a therapeutic for aquaculture settings that include viral infections with lower virus-shedding rates than IHNV or where higher viral titers are required to initiate infection of naive fish. Importantly, our data also suggest that LJ001-inactivated IHNV elicited an innate immune response in the rainbow trout host, making LJ001 potentially useful for future vaccination approaches.

IMPORTANCE
Viral diseases in aquaculture are challenging because there are few preventative measures and/or treatments. Broad-spectrum antivirals are highly sought after and studied because they target common components of viruses. In our studies, we used LJ001, a broad-spectrum antiviral compound that specifically inhibits enveloped viruses. We used the fish rhabdovirus infectious hematopoietic necrosis virus (IHNV) as a model to study aquatic enveloped virus diseases and their inhibition. We demonstrated inhibition of IHNV by LJ001 both in cell culture as well as in live fish. Additionally, we showed that LJ001 inhibited the transmission of IHNV from infected fish to healthy fish, which lays the groundwork for using LJ001 as a possible therapeutic for aquatic viruses. Our results also suggest that virus inactivated by LJ001 induces an immune response, showing potential for future preventative (e.g., vaccine) applications.
Random versus Cell Cycle-Regulated Replication Initiation in Bacteria: Insights from Studying Vibrio cholerae Chromosome 2
Authors: Ramachandran Revathy , Jha Jyoti , Paulsson Johan , Chattoraj Dhruba 
Published: December 2016

SUMMARY

Bacterial chromosomes initiate replication at a fixed time in the cell cycle, whereas there is generally no particular time for plasmid replication initiation or chromosomal replication initiation from integrated plasmids. In bacteria with divided genomes, the replication system of one of the chromosomes typically resembles that of bacteria with undivided genomes, whereas the remaining chromosomes have plasmid-like replication systems. For example, in
Vibrio cholerae
, a bacterium with two chromosomes (chromosome 1 [Chr1] and Chr2), the Chr1 system resembles that of the
Escherichia coli
chromosome, and the Chr2 system resembles that of iteron-based plasmids. However, Chr2 still initiates replication at a fixed time in the cell cycle and thus offers an opportunity to understand the molecular basis for the difference between random and cell cycle-regulated modes of replication. Here we review studies of replication control in Chr2 and compare it to those of plasmids and chromosomes. We argue that although the Chr2 control mechanisms in many ways are reminiscent of those of plasmids, they also appear to combine more regulatory features than are found on a typical plasmid, including some that are more typical of chromosomes. One of the regulatory mechanisms is especially novel, the coordinated timing of replication initiation of Chr1 and Chr2, providing the first example of communication between chromosomes for replication initiation.
Improving care for heart failure patients in primary care, GPs' perceptions: a qualitative evidence synthesis
Authors: Smeets Miek , Van Roy Sara , Aertgeerts Bert , Vermandere Mieke , Vaes Bert 
Published: December 2016

ObjectivesGeneral practitioners (GPs) play a key role in heart failure (HF) management. Despite multiple guidelines, the management of patients with HF in primary care is suboptimal. Therefore, all the qualitative evidence concerning GPs’ perceptions of managing HF in primary care was synthesised to identify barriers and facilitators for optimal care, and ideas for improvement.DesignQualitative evidence synthesis.MethodsSearches of MEDLINE, EMBASE, Web of Science and CINAHL databases up to 20/12/2015 were conducted. The Critical Appraisal Skills Programme's checklist for qualitative research was used for quality assessment. Thematic analysis was used as method of analysis.ResultsOf 5427 articles, 18 qualitative articles were included. Findings were organised in HF-specific factors, patient factors, physician factors and contextual factors. GPs’ uncertainty in all areas of HF management was highlighted. HF management started with an uncertain diagnosis, leading to difficulties with communication, treatment and advance care planning. Lack of access to specialised care and lack of knowledge were identified as important contributors to this uncertainty. In an effort to overcome this, strategies bringing evidence into practice should be promoted. GPs expressed the need for a multidisciplinary chronic care approach for HF. However, mixed experiences were noted with regard to interprofessional collaboration.ConclusionsThe main challenges identified in this synthesis were how to deal with GPs’ uncertainty about clinical practice, how to bring evidence into practice and how to work together as a multiprofessional team. These barriers were situated predominantly on the physician and contextual level. Targets to improve GPs’ HF care were identified.
Possible radii of compact stars: A relativistic approach
Authors: Kalam Mehedi , Hossein Sk Monowar , Molla Sajahan 
Published: December 2016

The inner structure of compact stars is checked from theoretical as well as observational points of view. In this paper, we determine the possible radii of six compact stars: two binary millisecond pulsars, namely PSR J1614-2230 and PSR J1903+327, studied by [P. B. Demorest, T. Pennucci, S. M. Ransom, M. S. E. Roberts and W. T. Hessels, Nature 467, 1081 (2010)] and four X-ray binaries, namely Cen X-3, SMC X-1, Vela X-1 and Her X-1 studied by [M. L. Rawls et al., Astrophys. J. 730, 25 (2011)]. Interestingly, we see that density of the star does not vanishes at the boundary though it is maximum at the center which implies that these compact stars may be treated as strange stars rather than neutron stars. We propose a stiff equation of state (EoS) relating to pressure with matter density. We also obtain compactness (u) and surface redshift (Z[Formula: see text]) for the above-mentioned stars and compare it with the recent observational data.