bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Performance Evaluation of an Aero Engine Booster Pump
Authors: Mohammed Ashfaq C. , Ulaganathan Shivakumar , Kannan Lingamoorthy , Singaravelu Anbuchezhian , Degaonkar Girish K. 
Published: February 2016

The primary function of an aero engine fuel system is to supply metered fuel to the combustion chamber at all operating conditions based on the flow demand set by the engine controller. Centrifugal pump is one of the components in fuel system that feeds fuel to the HP pump. Impeller design is a critical one which dictates the overall performance of centrifugal pump. This paper discusses about design and performance evaluation of impeller with twisted blade configuration. Impeller design is performed based on Euler’s one dimensional theory.
Steady state performance of the impeller at design and off-design operating conditions is analyzed by using commercial CFD code ANSYS-CFX with a standard SST turbulence model. The governing mathematical model for flow analysis is a three dimensional incompressible Reynolds Averaged Navier-Stokes (RANS) equation. Cavitation phenomenon is simulated in the CFD multiphase analysis to assess the pump impeller performance under cavitation at different NPSH values. Rayleigh-Plesset cavitation model is used along with RANS equation to perform cavitation analysis.
From this study, the simulation method and technique adapted is appropriate for predicting the performance of impeller of centrifugal pump with or without cavitation. Performance of the impeller reduces drastically as there is decrease in NPSH. The prediction of critical NPSH is vital for safer operation of the pump, specifically at high altitude the pump inlet pressure falls which may result in cavitation during operation.
Numerical Study of Variable Camber Inlet Guide Vane on Low Speed Axial Compressor
Authors: Rajesh Emandi , Roy Bhaskar 
Published: February 2016

The modern engine has the requirement of high pressure ratio compressors. High diffusion blades are used to cater to this requirement. The high diffusion blades suffer from the low incidence range. A variable geometry inlet guide vane is used to improve the incidence range and to have an increased stable operating range.
In this paper a variable camber inlet guide is proposed in place of an existing inlet guide vane (IGV) to operate the compressor at increased stable operating range or to operate at improved efficiency at off design point. Numerical analysis is carried out in ANSYS CFX©. The existing compressor consists of IGV (20 blades) , rotor (43 blades) and stator (52 blades). The rotor rotates at 2400 rpm in clockwise direction.
The IGV blade is split two part forward blade and aft blade. Numerical studies are conducted to study the effect of varying the stagger angle on the performance of the compressor. The aft blade is given rotation in clockwise direction for +5° and +10°. The numerical results obtained are compared to the same stagger angle with full blades. It is observed that marginal improvement in the pressure ratio and efficiency. 7% stall margin improvement is achieved with slotted blade in place a fixed IGV at 0° setting angle. A new compressor characteristics is estimated which shows that the compressor can be operated to the left of the fixed-IGV-stage peak pressure with high efficiency.
Quantifying masking in clinical mammograms via local detectability of simulated lesions
Authors: Mainprize James G. , Alonzo‐Proulx Olivier , Jong Roberta A. , Yaffe Martin J. 
Published: February 2016

Purpose:High mammographic density is known to be associated with decreased sensitivity of mammography. Recent changes in the BI‐RADS® density assessment address the effect of masking by densities, but the BI‐RADS® assessment remains qualitative and achieves only moderate agreement between radiologists. An automated, quantitative algorithm that estimates the likelihood of masking of simulated masses in a mammogram by dense tissue has been developed. The algorithm considers both the effects of loss of contrast due to density and the distracting texture or appearance of dense tissue.Methods:A local detectability (dL) map is created by tessellating the mammograms into overlapping regions of interest (ROIs), for which the detectability by a non‐prewhitening observer is computed using local estimates of the noise power spectrum and volumetric breast density (VBD). The dL calculation was validated in a 4‐alternative forced‐choice observer study on the ROIs of 150 craniocaudal digital mammograms. The dL metric was compared against the inverse threshold contrast, (ΔμT)−1 from the observer study, the anatomic noise parameter β, the radiologist's BI‐RADS® density category, and a validated measure of VBD (Cumulus).Results:The mean dL had a high correlation of r = 0.915 and r = 0.699 with (ΔμT)−1 in the computerized and human observer study, respectively. In comparison, the local VBD estimate had a low correlation of 0.538 with (ΔμT)−1. The mean dL had a correlation of 0.663, 0.835, and 0.696 with BI‐RADS density, β, and Cumulus VBD, respectively.Conclusions:The proposed dL metric may be useful in characterizing the potential for lesion masking by dense tissue. Because it uses information about the anatomic noise or tissue appearance, it is more closely linked to lesion detectability than VBD metrics.
Technical Note: Compact three‐tesla magnetic resonance imager with high‐performance gradients passes ACR image quality and acoustic noise tests
Authors: Weavers Paul T. , Shu Yunhong , Tao Shengzhen , Huston John , Lee Seung‐Kyun , Graziani Dominic , Mathieu Jean‐Baptiste , Trzasko Joshua D. , Foo Thomas K.‐F. , Bernstein Matt A. 
Published: February 2016

Purpose:A compact, three‐tesla magnetic resonance imaging (MRI) system has been developed. It features a 37 cm patient aperture, allowing the use of commercial receiver coils. Its design allows simultaneously for gradient amplitudes of 85 millitesla per meter (mT/m) sustained and 700 tesla per meter per second (T/m/s) slew rates. The size of the gradient system allows for these simultaneous performance targets to be achieved with little or no peripheral nerve stimulation, but also raises a concern about the geometric distortion as much of the imaging will be done near the system's maximum 26 cm field‐of‐view. Additionally, the fast switching capability raises acoustic noise concerns. This work evaluates the system for both the American College of Radiology's (ACR) MRI image quality protocol and the Food and Drug Administration's (FDA) nonsignificant risk (NSR) acoustic noise limits for MR. Passing these two tests is critical for clinical acceptance.Methods:In this work, the gradient system was operated at the maximum amplitude and slew rate of 80 mT/m and 500 T/m/s, respectively. The geometric distortion correction was accomplished by iteratively determining up to the tenth order spherical harmonic coefficients using a fiducial phantom and position‐tracking software, with seventh order correction utilized in the ACR test. Acoustic noise was measured with several standard clinical pulse sequences.Results:The system passes all the ACR image quality tests. The acoustic noise as measured when the gradient coil was inserted into a whole‐body MRI system conforms to the FDA NSR limits.Conclusions:The compact system simultaneously allows for high gradient amplitude and high slew rate. Geometric distortion concerns have been mitigated by extending the spherical harmonic correction to higher orders. Acoustic noise is within the FDA limits.
Coexistent Malnutrition Is Associated with Perturbations in Systemic and Antigen-Specific Cytokine Responses in Latent Tuberculosis Infection
Authors: Anuradha Rajamanickam , Munisankar Saravanan , Bhootra Yukthi , Kumar Nathalla Pavan , Dolla Chandrakumar , Kumaran Paul , Babu Subash 
Published: February 2016

ABSTRACTMalnutrition, as defined by low body mass index (BMI), is a major risk factor for the development of active tuberculosis (TB), although the biological basis underlying this susceptibility remains poorly characterized. To verify whether malnutrition affects the systemic and antigen-specific cytokine levels in individuals with latent TB (LTB), we examined circulating and TB antigen-stimulated levels of cytokines in individuals with LTB and low BMI (LBMI) and compared them with those in individuals with LTB and normal BMI (NBMI). Coexistent LBMI with LTB was characterized by diminished circulating levels of type 1 (gamma interferon [IFN-γ] and tumor necrosis factor alpha [TNF-α]), type 2 (interleukin-4 [IL-4]), type 17 (IL-22), and other proinflammatory (IL-1α, IL-1β, and IL-6) cytokines but elevated levels of other type 2 (IL-5 and IL-13) and regulatory (IL-10 and transforming growth factor beta [TGF-β]) cytokines. In addition, LBMI with LTB was associated with diminished TB antigen-induced IFN-γ, TNF-α, IL-6, IL-1α, and IL-1β levels. Finally, there was a significant positive correlation between BMI values and TNF-α and IL-1β levels and a significant negative correlation between BMI values and IL-2, IL-10, and TGF-β levels in individuals with LTB. Therefore, our data reveal that latent TB with a coexistent low BMI is characterized by diminished protective cytokine responses and heightened regulatory cytokine responses, providing a potential biological mechanism for the increased risk of developing active TB.
Evaluation of the Safety, Tolerability, and Immunogenicity of an Oral, Inactivated Whole-Cell Shigella flexneri 2a Vaccine in Healthy Adult Subjects
Authors: Chakraborty Subhra , Harro Clayton , DeNearing Barbara , Bream Jay , Bauers Nicole , Dally Len , Flores Jorge , Van de Verg Lillian , Sack David A. , Walker Richard 
Published: February 2016

ABSTRACTShigellacauses high morbidity and mortality worldwide, but there is no licensed vaccine for shigellosis yet. We evaluated the safety and immunogenicity of a formalin-inactivated whole-cellShigella flexneri2a vaccine, Sf2aWC, given orally to adult volunteers. In a double-blind, placebo-controlled trial, 82 subjects were randomized to receive three doses of vaccine in dose escalation (2.6 ± 0.8 × 108, × 109, × 1010, and × 1011vaccine particles/ml). Vaccine safety was actively monitored, and antigen-specific systemic and mucosal immune responses were determined in serum, antibody in lymphocyte supernatant (ALS), and fecal samples. Cytokines were measured in the serum. Sf2aWC was well tolerated and generally safe at all four dose levels. The vaccine resulted in a dose-dependent immune response. At the highest dose, the vaccine induced robust responses to lipopolysaccharide (LPS) in both serum and ALS samples. The highest magnitude and frequency of responses occurred after the first dose in almost all samples but was delayed for IgG in serum. Fifty percent of the vaccinees had a >4-fold increase in anti-LPS fecal antibody titers. Responses to invasion plasmid antigens (Ipa) were low. The levels of interleukin-17 (IL-17), IL-2, gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and IL-10 were increased, and IL-8 was decreased immediately after first dose, but these changes were very transient. This phase I trial demonstrated that the Sf2aWC vaccine, a relatively simple vaccine concept, was safe and immunogenic. The vaccine elicited immune responses which were comparable to those induced by a live, attenuatedShigellavaccine that was protective in prior human challenge studies.
Multiplex Antibody Detection for Noninvasive Genus-Level Diagnosis of Prosthetic Joint Infection
Authors: Marmor Simon , Bauer Thomas , Desplaces Nicole , Heym Beate , Roux Anne-Laure , Sol Olivier , Rogé Julie , Mahé Florence , Désiré Laurent , Aegerter Philippe , Ghout Idir , Ropers Jacques , Gaillard Jean-Louis , Rottman Martin 
Published: February 2016

ABSTRACT

We developed and evaluated a multiplex antibody detection-based immunoassay for the diagnosis of prosthetic joint infections (PJIs). Sixteen protein antigens from three
Staphylococcus
species (
Staphylococcus aureus
,
Staphylococcus epidermidis
, and
Staphylococcus lugdunensis
) (8 antigens),
Streptococcus agalactiae
(4 antigens), and
Propionibacterium acnes
(4 antigens) were selected by comparative immunoproteomics using serum samples from PJI cases versus controls. A bead-based multiplex immunoassay that measured serum IgG against purified, recombinant forms of each of the 16 antigens was developed. We conducted a prospective study to evaluate the performance of the assay. A PJI was defined by the presence of a sinus tract and/or positive intraoperative sample cultures (at least one sample yielding a virulent organism or at least two samples yielding the same organism). A total of 455 consecutive patients undergoing revision or resection arthroplasty (hip, 66.3%; knee, 29.7%; shoulder, 4%) at two French reference centers for the management of PJI were included: 176 patients (38.7%) were infected and 279 (61.3%) were not. About 60% of the infections involved at least one of the species targeted by the assay. The sensitivity/specificity values were 72.3%/80.7% for targeted staphylococci, 75%/92.6% for
S. agalactiae
, and 38.5%/84.8% for
P. acnes
. The assay was more sensitive for infections occurring >3 months after arthroplasty and for patients with an elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR). However, it detected 64.3% and 58.3% of targeted staphylococcal infections associated with normal CRP and ESR values, respectively. This new multiplex immunoassay approach is a novel noninvasive tool to evaluate patients suspected of having PJIs and provides information complementary to that from inflammatory marker values.
Inactivating Zaire Ebolavirus in Whole-Blood Thin Smears Used for Malaria Diagnosis
Authors: Cutts Todd A. , Cook Bradley W. M. , Poliquin P. Guillaume , Strong James E. , Theriault Steven S. 
Published: February 2016

ABSTRACT
Malaria is an important mimic or coinfection in potential Ebolavirus disease patients. Here, we evaluated the efficacy of the 100% methanol-inactivating Zaire Ebolavirus Makona variant for malaria thin-smear preparation. We determined that 100% methanol completely inactivated the virus after 15 min.
Comparative Detection and Quantification of Arcobacter butzleri in Stools from Diarrheic and Nondiarrheic People in Southwestern Alberta, Canada
Authors: Webb Andrew L. , Boras Valerie F. , Kruczkiewicz Peter , Selinger L. Brent , Taboada Eduardo N. , Inglis G. Douglas 
Published: February 2016

ABSTRACT

Arcobacter butzleri
has been linked to enteric disease in humans, but its pathogenicity and epidemiology remain poorly understood. The lack of suitable detection methods is a major limitation. Using comparative genome analysis, we developed PCR primers for direct detection and quantification of
A. butzleri
DNA in microbiologically complex matrices. These primers, along with existing molecular and culture-based methods, were used to detect
A. butzleri
and enteric pathogens in stools of diarrheic and nondiarrheic people (
n
= 1,596) living in southwestern Alberta, Canada, from May to November 2008. In addition, quantitative PCR was used to compare
A. butzleri
densities in diarrheic and nondiarrheic stools.
Arcobacter butzleri
was detected more often by PCR (59.6%) than by isolation methods (0.8%). Comparison by PCR-based detection found no difference in the prevalence of
A. butzleri
between diarrheic (56.7%) and nondiarrheic (45.5%) individuals. Rates of detection in diarrheic stools peaked in June (71.1%) and October (68.7%), but there was no statistically significant correlation between the presence of
A. butzleri
and patient age, sex, or place of habitation. Densities of
A. butzleri
DNA in diarrheic stools (1.6 ± 0.59 log
10
copies mg
−1
) were higher (
P
= 0.007) than in nondiarrheic stools (1.3 ± 0.63 log
10
copies mg
−1
). Of the 892 diarrheic samples that were positive for
A. butzleri
, 74.1% were not positive for other bacterial and/or viral pathogens. The current study supports previous work suggesting that
A. butzleri
pathogenicity is strain specific and/or dependent on other factors, such as the level of host resistance.
Performance of the New Aptima HCV Quant Dx Assay in Comparison to the Cobas TaqMan HCV2 Test for Use with the High Pure System in Detection and Quantification of Hepatitis C Virus RNA in Plasma or Serum
Authors: Schalasta Gunnar , Speicher Andrea , Börner Anna , Enders Martin 
Published: February 2016

ABSTRACT

Quantitating the level of hepatitis C virus (HCV) RNA is the standard of care for monitoring HCV-infected patients during treatment. The performances of commercially available assays differ for precision, limit of detection, and limit of quantitation (LOQ). Here, we compare the performance of the Hologic Aptima HCV Quant Dx assay (Aptima) to that of the Roche Cobas TaqMan HCV test, version 2.0, using the High Pure system (HPS/CTM), considered a reference assay since it has been used in trials defining clinical decision points in patient care. The assays' performance characteristics were assessed using HCV RNA reference panels and plasma/serum from chronically HCV-infected patients. The agreement between the assays for the 3 reference panels was good, with a difference in quantitation values of <0.5 log. High concordance was demonstrated between the assays for 245 clinical samples (kappa = 0.80; 95% confidence interval [CI], 0.720 to 0.881); however, Aptima detected and/or quantitated 20 samples that HPS/CTM did not detect, while Aptima did not detect 1 sample that was quantitated by HPS/CTM. For the 165 samples quantitated by both assays, the values were highly correlated (
R
= 0.98;
P
< 0.0001). The linearity of quantitation from concentrations of 1.4 to 6 log was excellent for both assays for all HCV genotypes (GT) tested (GT 1a, 1b, 2b, and 3a) (
R
2
> 0.99). The assays had similar levels of total and intra-assay variability across all genotypes at concentrations from 1,000 to 25 IU/ml. Aptima had a greater analytical sensitivity, quantitating more than 50% of replicates at 25-IU/ml target. Aptima showed performance characteristics comparable to those of HPS/CTM and increased sensitivity, making it suitable for use as a clinical diagnostic tool on the fully automated Panther platform.
Role of TSPAN9 in Alphavirus Entry and Early Endosomes
Authors: Stiles Katie M. , Kielian Margaret 
Published: February 2016

ABSTRACT
Alphaviruses are small enveloped RNA viruses that infect cells via clathrin-mediated endocytosis and low-pH-triggered fusion in the early endosome. Using a small interfering RNA (siRNA) screen in human cells, we previously identified TSPAN9 as a host factor that promotes infection by the alphaviruses Sindbis virus (SINV), Semliki Forest virus (SFV), and chikungunya virus (CHIKV). Depletion of TSPAN9 specifically decreases SFV membrane fusion in endosomes. TSPAN9 is a member of the tetraspanin family of multipass membrane proteins, but its cellular function is currently unknown. Here we used U-2 OS cells stably overexpressing TSPAN9 to show that TSPAN9 is localized at the plasma membrane and in early and late endosomes. Internalized SFV particles colocalized with TSPAN9 in vesicles early during infection. Depletion of TSPAN9 led to reductions in the amounts of the late endosomal proteins LAMP1 and CD63 and an increase in the amount of LAMP2. However, TSPAN9 depletion did not alter the delivery of SFV to early endosomes or change their pH or protease activity. Comparative studies showed that TSPAN9 depletion strongly inhibited infection by several viruses that fuse in early endosomes (SFV, SINV, CHIKV, and vesicular stomatitis virus [VSV]), while viruses that fuse in the late endosome (recombinant VSV-Lassa and VSV-Junin), including an SFV point mutant with a lower pH threshold for fusion (SFV E2 T12I), were relatively resistant. Our data suggest that TSPAN9 modulates the early endosome compartment to make it more permissive for membrane fusion of early-penetrating viruses.

IMPORTANCE
Alphaviruses are spread by mosquitoes and can cause serious human diseases such as arthritis and encephalitis. Recent outbreaks of CHIKV infection are responsible for millions of cases of acute illness and long-term complications. There are no vaccines or antiviral treatments for these important human pathogens. Alphaviruses infect host cells by utilizing the endocytic machinery of the cell and fusing their membrane with that of the endosome. Although the mechanism of virus-membrane fusion is well studied, we still know relatively little about the host cell proteins that are involved in alphavirus entry. Here we characterized the role of the host membrane protein TSPAN9 in alphavirus infection. TSPAN9 was localized to early endosomes containing internalized alphavirus, and depletion of TSPAN9 inhibited virus fusion with the early endosome membrane. In contrast, infection of viruses that enter through the late endosome was relatively resistant to TSPAN9 depletion, suggesting an important role for TSPAN9 in the early endosome.
Transient CD4+T Cell Depletion Results in Delayed Development of Functional Vaccine-Elicited Antibody Responses
Authors: Provine Nicholas M. , Badamchi-Zadeh Alexander , Bricault Christine A. , Penaloza-MacMaster Pablo , Larocca Rafael A. , Borducchi Erica N. , Seaman Michael S. , Barouch Dan H. 
Published: February 2016

ABSTRACTWe have recently demonstrated that CD4+T cell help is required at the time of adenovirus (Ad) vector immunization for the development of functional CD8+T cell responses, but the temporal requirement for CD4+T cell help for the induction of antibody responses remains unclear. Here we demonstrate that induction of antibody responses in C57BL/6 mice can occur at a time displaced from the time of Ad vector immunization by depletion of CD4+T cells. Transient depletion of CD4+T cells at the time of immunization delays the development of antigen-specific antibody responses but does not permanently impair their development or induce tolerance against the transgene. Upon CD4+T cell recovery, transgene-specific serum IgG antibody titers develop and reach a concentration equivalent to that in undepleted control animals. These delayed antibody responses exhibit no functional defects with regard to isotype, functional avidity, expansion after boosting immunization, or the capacity to neutralize a simian immunodeficiency virus (SIV) Env-expressing pseudovirus. The development of this delayed transgene-specific antibody response is temporally linked to the expansion ofde novoantigen-specific CD4+T cell responses, which develop after transient depletion of CD4+T cells. These data demonstrate that functional vaccine-elicited antibody responses can be induced even if CD4+T cell help is provided at a time markedly separated from the time of vaccination.IMPORTANCECD4+T cells have a critical role in providing positive help signals to B cells, which promote robust antibody responses. The paradigm is that helper signals must be provided immediately upon antigen exposure, and their absence results in tolerance against the antigen. Here we demonstrate that, in contrast to the current model that the absence of CD4+T cell help at priming results in long-term antibody nonresponsiveness, antibody responses can be induced by adenovirus vector immunization or alum-adjuvanted protein immunization even if CD4+T cell help is not provided until >1 month after immunization. These data demonstrate that the time when CD4+T cell help signals must be provided is more dynamic and flexible than previously appreciated. These data suggest that augmentation of CD4+T cell helper function even after the time of vaccination can enhance vaccine-elicited antibody responses and thereby potentially enhance the immunogenicity of vaccines in immunocompromised individuals.