bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parametric Cooling Study of Single-Row Cylindrical Film Holes on Pressure Side of a Rotor Blade
Authors: Chi Zhongran , Liu Haiqing , Zang Shusheng 
Published: August 2017

Film cooling of 1st stage rotor blades strongly relates to the aerodynamic performance and life expectation of gas turbine. In this piece of work, a parametric study was carried out based on 3D RANS CFD methods to systematically investigate both cooling performance and aerodynamic loss of various film holes’ arrangements on the pressure side (PS) of a realistic rotor blade. In each CFD case, cylindrical film holes were arranged in one row with P/D around 4.0. More than one hundred CFD cases were carried out with various dimensionless streamwise locations (0.1, 0.2, ..., and 0.7), compound angles (−60°, −30°, ..., and 90°), and relative coolant massflows (0.2%, 0.3%, 0.45%, 0.7%, and 1.0% of mainstream massflow).
Detailed distributions of adiabatic film cooling effectiveness on blade surface and aerodynamic loss with film cooling were computed for each case. It was found that coolant massflow was the decisive factor of aerodynamic efficiency φ. For near-LE film holes, −60° compound angle gave higher and more uniform η distributions at various coolant massflows. And the separation near LE could be suppressed, improving local cooling at near-hub on PS. For downstream film holes, 60° and −60° compound angles provided equivalent cooling performances, which were also better than other cases. The cooling characteristics of film holes with −30° compound angle were more susceptible to both coolant massflow and the location of ejection, which was mainly because of the blow-off and reattachment of coolant jets. For the cases with 90° compound angle, the distributions of η were generally similar, and the values increased monotonically as coolant massflows get larger.
Improved Hierarchical Modelling for Aerodynamically Coupled Systems
Authors: Watson Rob , Cui Jiahuan , Ma Yunfei , Tyacke James , Vadlamani Nagabhushana Rao , Alam Mohammed F. , Dai Yushuang , Tucker Paul G. , Cao Teng , Hield Paul , Wilson Mark , Menzies Kevin , Sheaf Christopher 
Published: August 2017

Strong aerodynamic coupling can make the high fidelity simulation of a number of critical aero-engine components prohibitively expensive — particularly within the timeframes of industrial design cycles. This paper develops a body force based hierarchy of approaches to modelling the effects of blade rows. These are envisaged as allowing the computationally expensive parts of coupled systems to be resolved much more cheaply, rendering the cost of the overall simulation as more manageable. Simulation of the coupling that exists between the flow around an aero-engine intake and its fan is particularly emphasised, as this is becoming stronger and more performance critical with the modern trends towards the reduction of the relative diffuser length.
The use of the viscous smeared geometry level of fidelity is initially shown to be an effective model over a number of cases — a simple compressor blade row, a modern high bypass fan, and the Darmstadt rotor. After this, it is shown working as part of a coupled system in an intake experiencing cross-flow. Higher fidelity geometry representations are then considered, which mimic the effect of struts. Finally, a mix of various fidelity geometry representations and turbulence modelling approaches is shown to bring otherwise hugely expensive calculations within the realm of practical computation, in the form of a full fan-to-flap calculation.
Intrinsic Maturational Neonatal Immune Deficiencies and Susceptibility to Group B Streptococcus Infection
Authors: Korir Michelle L. , Manning Shannon D. , Davies H. Dele 
Published: August 2017

SUMMARY

Although a normal member of the gastrointestinal and vaginal microbiota, group B
Streptococcus
(GBS) can also occasionally be the cause of highly invasive neonatal disease and is an emerging pathogen in both elderly and immunocompromised adults. Neonatal GBS infections are typically transmitted from mother to baby either
in utero
or during passage through the birth canal and can lead to pneumonia, sepsis, and meningitis within the first few months of life. Compared to the adult immune system, the neonatal immune system has a number of deficiencies, making neonates more susceptible to infection. Recognition of GBS by the host immune system triggers an inflammatory response to clear the pathogen. However, GBS has developed several mechanisms to evade the host immune response. A comprehensive understanding of this interplay between GBS and the host immune system will aid in the development of new preventative measures and therapeutics.
A Single-Amino-Acid Substitution at Position 225 in Hemagglutinin Alters the Transmissibility of Eurasian Avian-Like H1N1 Swine Influenza Virus in Guinea Pigs
Authors: Wang Zeng , Yang Huanliang , Chen Yan , Tao Shiyu , Liu Liling , Kong Huihui , Ma Shujie , Meng Fei , Suzuki Yasuo , Qiao Chuanling , Chen Hualan 
Published: August 2017

ABSTRACT
Efficient transmission from human to human is the prerequisite for an influenza virus to cause a pandemic; however, the molecular determinants of influenza virus transmission are still largely unknown. In this study, we explored the molecular basis for transmission of Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses by comparing two viruses that are genetically similar but differ in their transmissibility in guinea pigs: the A/swine/Guangxi/18/2011 virus (GX/18) is highly transmissible by respiratory droplet in guinea pigs, whereas the A/swine/Heilongjiang/27/2012 virus (HLJ/27) does not transmit in this animal model. We used reverse genetics to generate a series of reassortants and mutants in the GX/18 background and tested their transmissibility in guinea pigs. We found that a single-amino-acid substitution of glycine (G) for glutamic acid (E) at position 225 (E225G) in the HA1 protein completely abolished the respiratory droplet transmission of GX/18, whereas the substitution of E for G at the same position (G225E) in HA1 enabled HLJ/27 to transmit in guinea pigs. We investigated the underlying mechanism and found that viruses bearing 225E in HA1 replicated more rapidly than viruses bearing 225G due to differences in assembly and budding efficiencies. Our study indicates that the amino acid 225E in HA1 plays a key role in EAH1N1 swine influenza virus transmission and provides important information for evaluating the pandemic potential of field influenza virus strains.

IMPORTANCE
Efficient transmission among humans is a prerequisite for a novel influenza virus to cause a human pandemic. Transmissibility of influenza viruses is a polygenic trait, and understanding the genetic determinants for transmissibility will provide useful insights for evaluating the pandemic potential of influenza viruses in the field. Several amino acids in the hemagglutinin (HA) protein of influenza viruses have been shown to be important for transmissibility, usually by increasing virus affinity for human-type receptors. In this study, we explored the genetic basis of the transmissibility difference between two Eurasian avian-like H1N1 (EAH1N1) swine influenza viruses in guinea pigs and found that the amino acid glutamic acid at position 225 in the HA1 protein plays a critical role in the transmission of EAH1N1 virus by increasing the efficiency of viral assembly and budding.
Mutation of the Putative Immunosuppressive Domain of the Retroviral Envelope Glycoprotein Compromises Infectivity
Authors: Eksmond Urszula , Jenkins Bryony , Merkenschlager Julia , Mothes Walther , Stoye Jonathan P. , Kassiotis George 
Published: August 2017

ABSTRACT
The envelope glycoprotein of diverse endogenous and exogenous retroviruses is considered inherently immunosuppressive. Extensive work mapped the immunosuppressive activity to a highly conserved domain, termed the immunosuppressive domain (ISD), in the transmembrane (TM) subunit of the envelope glycoprotein and identified two naturally polymorphic key residues that afford immunosuppressive activity to distinct envelope glycoproteins. Concurrent mutation of these two key residues (E14R and A20F) in the envelope glycoprotein of the Friend murine leukemia virus (F-MLV) ISD has been reported to abolish its immunosuppressive activity, without affecting its fusogenicity, and to weaken the ability of the virus to replicate specifically in immunocompetent hosts. Here, we show that mutation of these key residues did, in fact, result in a substantial loss of F-MLV infectivity, independently of host immunity, challenging whether associations exist between the two. Notably, a loss of infectivity incurred by the F-MLV mutant with the E14R and A20F double ISD mutation was conditional on expression of the ecotropic envelope receptor murine cationic amino acid transporter-1 (mCAT1) in the virus-producing cell. Indeed, the F-MLV mutant retained infectivity when it was produced by human cells, which naturally lack mCAT1 expression, but not by murine cells. Furthermore, mCAT1 overexpression in human cells impaired the infectivity of both the F-MLV double mutant and the wild-type F-MLV strain, suggesting a finely tuned relationship between the levels of mCAT1 in the producer cell and the infectivity of the virions produced. An adverse effect on this relationship, rather than disruption of the putative ISD, is therefore more likely to explain the loss of F-MLV infectivity incurred by mutations in key ISD residues E14 and A20.

IMPORTANCE
Retroviruses can interact with their hosts in ways that, although not entirely understood, can greatly influence their pathogenic potential. One such example is a putative immunosuppressive activity, which has been mapped to a conserved domain of the retroviral envelope glycoprotein of several exogenous as well as endogenous retroviruses. In this study, mutations naturally found in some envelope glycoproteins lacking immunosuppressive activity were shown to affect retrovirus infectivity only if the host cell that produced the retrovirus also expressed the cellular entry receptor. These findings shed light on a novel role for this conserved domain in providing the necessary stability to the envelope glycoprotein in order to withstand the interaction with the cellular receptor during virus formation. This function of the domain is critical for further elucidation of the mechanism of immunosuppression mediated by the retroviral envelope glycoprotein.
Baculovirus Molecular Evolution via Gene Turnover and Recurrent Positive Selection of Key Genes
Authors: Hill Tom , Unckless Robert L. 
Published: August 2017

ABSTRACT
Hosts and viruses are locked in an evolutionary arms race. Hosts are constantly evolving to suppress virulence and replication, while viruses, which are reliant on host machinery for survival and reproduction, develop counterstrategies to escape this immune defense. Viruses must also adapt to novel conditions while establishing themselves in a host species. Both processes provide strong selection for viral adaptation. Understanding adaptive evolution in insect viruses can help us to better understand adaptive evolution in general and is important due to the use of these viruses as biocontrol agents and for protecting ecologically or economically important species from outbreaks. Here we examine the molecular evolution of baculoviruses and nudiviruses, a group of insect-infecting viruses with key roles in biocontrol. We looked for signatures of selection between genomes of baculoviruses infecting a range of species and within a population of baculoviruses. Both analyses found only a few strong signatures of positive selection, primarily in replication- and transcription-associated genes and several structural protein genes. In both analyses, we detected a conserved complex of genes, including the helicase gene, showing consistently high levels of adaptive evolution, suggesting that they may be key in antagonistic coevolution to escape host suppression. These genes are integral to the baculovirus life cycle and may be good focal genes for developing baculoviruses as effective biocontrol agents or for targeting baculoviruses infecting ecologically relevant species. Recombination and complex genomes make evolution in these double-stranded DNA viruses more efficient than that in smaller RNA viruses with error-prone replication, as seen via signatures of selection in specific genes within a population of baculoviruses.

IMPORTANCE
Most viral evolutionary studies focus on RNA viruses. While these viruses cause many human and animal diseases, such studies leave us with a lesser understanding of how DNA viruses adapt to hosts and how the host responds to these pathogens. In this paper, we focus on the evolution of baculoviruses, a group of insect-infecting DNA viruses, many of which have been used in biocontrol. We find that most of the genome is under purifying selection, with only a few key genes evolving adaptively. Our results provide a glimpse into how DNA viruses differ from RNA viruses in their evolutionary dynamics and identify genes that are key to DNA virus adaptation, improving our understanding of how this group of pathogens evolves.
Hospitalisation of preterm infants with pertussis in the context of a maternal vaccination programme in England
Authors: Byrne Lisa , Campbell Helen , Andrews Nick , Ribeiro Sonia , Amirthalingam Gayatri 
Published: August 2017

AimsTo assess whether preterm infants are at increased risk of pertussis infection and whether this increased following introduction of a maternal pertussis vaccination in England, while examining characteristics of infants associated with more severe disease.MethodsInfants aged <60 days admitted between 1 April 2009 and 31 March 2016 with a pertussis diagnosis code were extracted from Hospital Episode Statistics (HES) data. HES data were reconciled with existing surveillance systems to capture maternal vaccination status where available. Cases were compared preimplementation and postimplementation of the maternal programme with respect to demography, preterm or full-term birth and coinfection. Survival analysis was undertaken to assess the impact of variables on duration of hospital stay.ResultsThe proportion of hospitalised preterm infants (138/1309, 10.6%) was higher than population estimates (7.4%), increasing from 9.8% (83/847) to 12.1% (56/462) following implementation of the maternal programme. Longer duration of hospital stay was associated with prematurity, younger age, additional respiratory illnesses and mothers unvaccinated in pregnancy. Of 13 deaths, 5 were preterm (38.5%) and 11 (84.6%) were female. A larger proportion of full-term infants’ (49/188, 26.1%) mothers had been vaccinated in pregnancy than preterm infants (7/49, 14.3%), with 14.3% of mothers of full-term cases vaccinated after 35 weeks.ConclusionsPreterm infants are over-represented in hospitalised pertussis cases and have less benefit from the maternal pertussis vaccination programme in England due to reduced opportunity for maternal vaccination.
Mothers’ knowledge and attitudes to sudden infant death syndrome risk reduction messages: results from a UK survey
Authors: Pease Anna S , Blair Peter S , Ingram Jenny , Fleming Peter J 
Published: August 2017

ObjectiveTo investigate mothers’ knowledge of reducing the risks for sudden infant death syndrome (SIDS) and attitudes towards safer sleep practices.Design and settingA cross-sectional survey was carried out in deprived areas of Bristol, UK. Recruitment took place in 2014 at local health visitor-led baby clinics.ParticipantsOf 432 mothers approached, 400 (93%) completed the face-to-face survey. Participants with infants at ‘higher’ risk of SIDS (using an algorithm based on a previous observational study) were compared with those at ‘lower’ risk.Main outcome measuresThe survey asked participants to recall three SIDS risk reduction strategies (unprompted), and scored responses to 14 SIDS risk-related infant sleep scenarios (prompted).ResultsOverall, 48/400 (12%) mothers were classified as higher risk. Mothers in the higher risk group were less likely to breast feed (multivariate OR=3.59(95% CI 1.46 to 8.86)), less likely to be able to cite two or more unprompted correct SIDS risk reduction strategies (multivariate OR=2.05(95% CI 1.02 to 4.13)) and scored lower on prompted safer sleep scenarios overall.Notably, only 206/400 (52%) of all mothers surveyed (33% in the higher risk group) from these deprived areas in Bristol identified infant sleep position as a risk reduction strategy for SIDS, despite 25 years of campaigns.ConclusionsMothers in the higher risk group were disadvantaged when it came to some aspects of knowledge of SIDS risk reduction and attitudes to safer sleep. The initial ‘Back-to Sleep’ message that dramatically reduced these deaths a generation ago needs more effective promotion for today’s generation of mothers.
Comparing glaucomatous disc change using stereo disc viewing and the MatchedFlicker programme in glaucoma experts and trainees
Authors: Schaefer Jamie L , Meyer Alissa M , Rodgers Cooper D , Rosenberg Nicole C , Leoncavallo Anthony J , Lukowski Zachary L , Greer Anthony B , Martorana Gina M , Zou Baiming , Shuster Jonathan J , Jay Katz L , Schuman Joel S , Kass Michael A , Sherwood Mark B 
Published: August 2017

Background/aimsThe objective of this study is to evaluate the accuracy and speed of trainees and experienced glaucoma specialists using the MatchedFlicker software against the manual examination of stereoscopic disc photographs for detecting glaucomatous optic disc change.MethodsThree experienced glaucoma specialists, two resident ophthalmologists and one glaucoma fellow from multiple institutions independently evaluated the same 140 image pairs from 100 glaucomatous/ocular hypertensive eyes using a handheld stereo viewer and the MatchedFlicker programme. Fifty had progression to glaucoma as determined by the Ocular Hypertension Treatment Study (OHTS) Optic Disc Reading Group and endpoint committee, and 50 more were negative controls for progression with photos taken a few minutes apart. Twenty photo pairs from each of the two groups were duplicated for reviewer variability analysis. The initial viewing method was randomised and then alternated for each group of 70 image pairs. Reviewer accuracy and evaluation time for each method were measured.ResultsEvaluators averaged 8.6 s faster per image pair (26%) with the MatchedFlicker programme than with the stereo viewer (p=0.0007). Evaluators correctly identified more image pairs when using the MatchedFlicker software over the stereo viewer (p=0.0003). There was no significant difference between the expert and trainee group in speed or overall accuracy for either method. Experts were significantly more consistent than trainees with the duplicate image pairs (p=0.029). Trainees appeared more reluctant to designate eyes as showing glaucoma progression than experts.ConclusionsBoth expert glaucoma specialists and ophthalmologists in various stages of training had greater accuracy and speed with the MatchedFlicker programme than with a handheld stereoscopic viewer.
Long-term outcomes with as-needed aflibercept in diabetic macular oedema: 2-year outcomes of the ENDURANCE extension study
Authors: Wykoff Charles C , Ou William C , Khurana Rahul N , Brown David M , Lloyd Clark W , Boyer David S 
Published: August 2017

Background/aimsTo evaluate the efficacy and safety of individualised 2.0 mg intravitreal aflibercept retreatment for diabetic macular oedema (DME) through the fifth year of management.MethodsThis is a phase IV, 2-year, open-label extension study. Sixty patients completing the 3-year VISTA DME (Study of Intravitreal Aflibercept Injection in Patients With Diabetic Macular Edema) phase III trial enrolled in the ENDURANCE (Long-Term Efficacy and Safety of Intravitreal Aflibercept for the Treatment of DME in Subjects Who Completed the VISTA DME Trial) extension study. All patients received aflibercept in the presence of clinically relevant DME. Intervals between visits were prescribed according to disease activity. The main outcome measure was mean aflibercept injections given through 2 years.ResultsA mean of 7.7 aflibercept injections were administered through 2 years. Fifteen (25%) patients required no retreatment and 48% (n=29) of patients received five or fewer injections through 2 years. Among patients who received at least one aflibercept retreatment during ENDURANCE, the mean number of injections through 2 years was 9.5. The mean visual acuity and central retinal thickness gains achieved during VISTA DME were maintained and stable during ENDURANCE. The most notable safety signal was progression of diabetic retinopathy. Six (10%) patients converted from non-proliferative to proliferative diabetic retinopathy (PDR), and a total of eight patients experienced PDR events occurring at a mean of 387 days following the previous aflibercept treatment.ConclusionThe need for aflibercept retreatment was substantially reduced in the fourth and fifth years of aflibercept dosing for DME following initiation of therapy in the VISTA DME trial. While vision gains achieved during the 3-year VISTA DME trial were maintained through ENDURANCE with a reduced treatment burden, clinically relevant worsening of diabetic retinopathy was observed with progression to PDR in 10% of the eyes.Trial registration numberNCT02299336
Does use of point-of-care testing improve cost-effectiveness of the NHS Health Check programme in the primary care setting? A cost-minimisation analysis
Authors: El-Osta Austen , Woringer Maria , Pizzo Elena , Verhoef Talitha , Dickie Claire , Ni Melody Z , Huddy Jeremy R , Soljak Michael , Hanna George B , Majeed Azeem 
Published: August 2017

ObjectiveTo determine if use of point of care testing (POCT) is less costly than laboratory testing to the National Health Service (NHS) in delivering the NHS Health Check (NHSHC) programme in the primary care setting.DesignObservational study and theoretical mathematical model with microcosting approach.SettingWe collected data on NHSHC delivered at nine general practices (seven using POCT; two not using POCT).ParticipantsWe recruited nine general practices offering NHSHC and a pathology services laboratory in the same area.MethodsWe conducted mathematical modelling with permutations in the following fields: provider type (healthcare assistant or nurse), type of test performed (total cholesterol with either lab fasting glucose or HbA1c), cost of consumables and variable uptake rates, including rate of non-response to invite letter and rate of missed [did not attend (DNA)] appointments. We calculated total expected cost (TEC) per 100 invites, number of NHSHC conducted per 100 invites and costs for completed NHSHC for laboratory and POCT-based pathways. A univariate and probabilistic sensitivity analysis was conducted to account for uncertainty in the input parameters.Main outcome measuresWe collected data on cost, volume and type of pathology services performed at seven general practices using POCT and a pathology services laboratory. We collected data on response to the NHSHC invitation letter and DNA rates from two general practices.ResultsTEC of using POCT to deliver a routine NHSHC is lower than the laboratory-led pathway with savings of £29 per 100 invited patients up the point of cardiovascular disease risk score presentation. Use of POCT can deliver NHSHC in one sitting, whereas the laboratory pathway offers patients several opportunities to DNA appointment.ConclusionsTEC of using POCT to deliver an NHSHC in the primary care setting is lower than the laboratory-led pathway. Using POCT minimises DNA rates associated with laboratory testing and enables completion of NHSHC in one sitting.