3,088 research outputs found
Fractal injectors to intensify liquid-phase processes by controlling the turbulent flow field
Fractal injectors can be used to intensify liquid-phase processes. The flow field, vortex structure and turbulent mixing performance induced by fractal injectors with three different fractal dimensions (D = 2, 2.58 and 3) are investigated. CFD simulations, using a renormalization group (RNG) k-Ξ΅ turbulence model, are validated with particle image velocimetry (PIV) measurements. The structure and formation mechanism of the vortices are studied. Both spiral and double toroidal vortices are produced, the latter by jet impingement. These vortices interact with each other within a fractal generating unit. For the same total volumetric flow rate, a fractal injector with D = 2.58 can achieve better mixing uniformity than fractal injectors with D = 2 or D = 3, while maintaining a similarly high mixing rate to when D = 2. This is due to enhanced entrainment by mutually interacting double toroidal vortex pairs and turbulent mixing
Detection of poliovirus by ICC/qPCR in concentrated water samples has greater sensitivity and is less costly using BGM cells in suspension as compared to monolayers
The integrated cell culture quantitative reverse transcriptase PCR (ICC/qRT-PCR) method is used in our lab to detect enteroviruses in environmental waters. Typically we utilize monolayers of 3 cell lines; buffalo green monkey kidney (BGM), human colonic carcinoma (CACO-2) and African rhesus monkey kidney (MA104) with the intent of providing one or more permissive hosts to a wide range of enteroviruses. In this study the BGM cell line was used to compare poliovirus infectivity in conventional monolayer cultures to BGM cells in suspensions. Propagated virus was subsequently amplified by qRT-PCR. Our PCR data showed lower cycle threshold (Ct) values in the suspensions which corresponded to a higher rate of infectivity than that observed in the monolayers. The difference in Ct values was determined statistically significant by One-way ANOVA (0.000). Infecting BGM cells in suspensions required less hands-on time, less chance of contamination and was more cost effective than utilizing the conventional monolayer technique
Antibodies against insulin measured by electrochemiluminescence predicts insulitis severity and disease onset in non-obese diabetic mice and can distinguish human type 1 diabetes status
Abstract Background The detection of insulin autoantibodies (IAA) aids in the prediction of autoimmune diabetes development. However, the long-standing, gold standard 125I-insulin radiobinding assay (RBA) has low reproducibility between laboratories, long sample processing times and requires the use of newly synthesized radiolabeled insulin for each set of assays. Therefore, a rapid, non-radioactive, and reproducible assay is highly desirable. Methods We have developed electrochemiluminescence (ECL)-based assays that fulfill these criteria in the measurement of IAA and anti-insulin antibodies (IA) in non-obese diabetic (NOD) mice and in type 1 diabetic individuals, respectively. Using the murine IAA ECL assay, we examined the correlation between IAA, histopathological insulitis, and blood glucose in a cohort of female NOD mice from 4 up to 36 weeks of age. We developed a human IA ECL assay that we compared to conventional RBA and validated using samples from 34 diabetic and 59 non-diabetic individuals in three independent laboratories. Results Our ECL assays were rapid and sensitive with a broad dynamic range and low background. In the NOD mouse model, IAA levels measured by ECL were positively correlated with insulitis severity, and the values measured at 8-10 weeks of age were predictive of diabetes onset. Using human serum and plasma samples, our IA ECL assay yielded reproducible and accurate results with an average sensitivity of 84% at 95% specificity with no statistically significant difference between laboratories. Conclusions These novel, non-radioactive ECL-based assays should facilitate reliable and fast detection of antibodies to insulin and its precursors sera and plasma in a standardized manner between laboratories in both research and clinical settings. Our next step is to evaluate the human IA assay in the detection of IAA in prediabetic subjects or those at risk of type 1 diabetes and to develop similar assays for other autoantibodies that together are predictive for the diagnosis of this common disorder, in order to improve prediction and facilitate future therapeutic trials.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
Bayesian hierarchical clustering for studying cancer gene expression data with unknown statistics
Clustering analysis is an important tool in studying gene expression data. The Bayesian hierarchical clustering (BHC) algorithm can automatically infer the number of clusters and uses Bayesian model selection to improve clustering quality. In this paper, we present an extension of the BHC algorithm. Our Gaussian BHC (GBHC) algorithm represents data as a mixture of Gaussian distributions. It uses normal-gamma distribution as a conjugate prior on the mean and precision of each of the Gaussian components. We tested GBHC over 11 cancer and 3 synthetic datasets. The results on cancer datasets show that in sample clustering, GBHC on average produces a clustering partition that is more concordant with the ground truth than those obtained from other commonly used algorithms. Furthermore, GBHC frequently infers the number of clusters that is often close to the ground truth. In gene clustering, GBHC also produces a clustering partition that is more biologically plausible than several other state-of-the-art methods. This suggests GBHC as an alternative tool for studying gene expression data. The implementation of GBHC is available at https://sites.
google.com/site/gaussianbhc
Improving ductal carcinoma in situ classification by convolutional neural network with exponential linear unit and rank-based weighted pooling
Ductal carcinoma in situ (DCIS) is a pre-cancerous lesion in the ducts of the breast, and early diagnosis is crucial for optimal
therapeutic intervention. Thermography imaging is a non-invasive imaging tool that can be utilized for detection of DCIS and
although it has high accuracy (~88%), it is sensitivity can still be improved. Hence, we aimed to develop an automated artificial
intelligence-based system for improved detection of DCIS in thermographs. This study proposed a novel artificial intelligence
based system based on convolutional neural network (CNN) termed CNN-BDER on a multisource dataset containing 240
DCIS images and 240 healthy breast images. Based on CNN, batch normalization, dropout, exponential linear unit and
rank-based weighted pooling were integrated, along with L-way data augmentation. Ten runs of tenfold cross validation were
chosen to report the unbiased performances. Our proposed method achieved a sensitivity of 94.08Β±1.22%, a specificity
of 93.58Β±1.49 and an accuracy of 93.83Β±0.96. The proposed method gives superior performance than eight state-of-theart
approaches and manual diagnosis. The trained model could serve as a visual question answering system and improve
diagnostic accuracy.British Heart Foundation Accelerator Award, UKRoyal Society International Exchanges Cost Share Award, UK
RP202G0230Hope Foundation for Cancer Research, UK
RM60G0680Medical Research Council Confidence in Concept Award, UK
MC_PC_17171MINECO/FEDER, Spain/Europe
RTI2018-098913-B100
A-TIC-080-UGR1
Nanofluids Containing Ξ³-Fe2O3 Nanoparticles and Their Heat Transfer Enhancements
Homogeneous and stable magnetic nanofluids containing Ξ³-Fe2O3 nanoparticles were prepared using a two-step method, and their thermal transport properties were investigated. Thermal conductivities of the nanofluids were measured to be higher than that of base fluid, and the enhanced values increase with the volume fraction of the nanoparticles. Viscosity measurements showed that the nanofluids demonstrated Newtonian behavior and the viscosity of the nanofluids depended strongly on the tested temperatures and the nanoparticles loadings. Convective heat transfer coefficients tested in a laminar flow showed that the coefficients increased with the augment of Reynolds number and the volume fraction
Secular evolution versus hierarchical merging: galaxy evolution along the Hubble sequence, in the field and rich environments
In the current galaxy formation scenarios, two physical phenomena are invoked
to build disk galaxies: hierarchical mergers and more quiescent external gas
accretion, coming from intergalactic filaments. Although both are thought to
play a role, their relative importance is not known precisely. Here we consider
the constraints on these scenarios brought by the observation-deduced star
formation history on the one hand, and observed dynamics of galaxies on the
other hand: the high frequency of bars and spirals, the high frequency of
perturbations such as lopsidedness, warps, or polar rings.
All these observations are not easily reproduced in simulations without
important gas accretion. N-body simulations taking into account the mass
exchange between stars and gas through star formation and feedback, can
reproduce the data, only if galaxies double their mass in about 10 Gyr through
gas accretion. Warped and polar ring systems are good tracers of this
accretion, which occurs from cold gas which has not been virialised in the
system's potential. The relative importance of these phenomena are compared
between the field and rich clusters. The respective role of mergers and gas
accretion vary considerably with environment.Comment: 18 pages, 8 figures, review paper to "Penetrating Bars through Masks
of Cosmic Dust: the Hubble Tuning Fork Strikes a New Note", Pilanesberg, ed.
D. Block et al., Kluwe
Controlling multistability in a vibro-impact capsule system
This is the final version of the article. Available from Springer Verlag via the DOI in this record.This work concerns the control of multistability in a vibro-impact capsule system driven by a harmonic excitation. The capsule is able to move forward and backward in a rectilinear direction, and the main objective of this work is to control such motion in the presence of multiple coexisting periodic solutions. A position feedback controller is employed in this study, and our numerical investigation demonstrates that the proposed control method gives rise to a dynamical scenario with two coexisting solutions, corresponding to forward and backward progression. Therefore, the motion direction of the system can be controlled by suitably perturbing its initial conditions, without altering the system parameters. To study the robustness of this control method, we apply numerical continuation methods in order to identify a region in the parameter space in which the proposed controller can be applied. For this purpose, we employ the MATLAB-based numerical platform COCO, which supports the continuation and bifurcation detection of periodic orbits of non-smooth dynamical systems.The second author has been supported by a Georg Forster Research Fellowship granted by the Alexander von Humboldt Foundation, Germany. The authors would like to thank Dr. Haibo Jiang for stimulating discussions and comments on this work
Disparities and risks of sexually transmissible infections among men who have sex with men in China: a meta-analysis and data synthesis.
BACKGROUND: Sexually transmitted infections (STIs), including Hepatitis B and C virus, are emerging public health risks in China, especially among men who have sex with men (MSM). This study aims to assess the magnitude and risks of STIs among Chinese MSM. METHODS: Chinese and English peer-reviewed articles were searched in five electronic databases from January 2000 to February 2013. Pooled prevalence estimates for each STI infection were calculated using meta-analysis. Infection risks of STIs in MSM, HIV-positive MSM and male sex workers (MSW) were obtained. This review followed the PRISMA guidelines and was registered in PROSPERO. RESULTS: Eighty-eight articles (11 in English and 77 in Chinese) investigating 35,203 MSM in 28 provinces were included in this review. The prevalence levels of STIs among MSM were 6.3% (95% CI: 3.5-11.0%) for chlamydia, 1.5% (0.7-2.9%) for genital wart, 1.9% (1.3-2.7%) for gonorrhoea, 8.9% (7.8-10.2%) for hepatitis B (HBV), 1.2% (1.0-1.6%) for hepatitis C (HCV), 66.3% (57.4-74.1%) for human papillomavirus (HPV), 10.6% (6.2-17.6%) for herpes simplex virus (HSV-2) and 4.3% (3.2-5.8%) for Ureaplasma urealyticum. HIV-positive MSM have consistently higher odds of all these infections than the broader MSM population. As a subgroup of MSM, MSW were 2.5 (1.4-4.7), 5.7 (2.7-12.3), and 2.2 (1.4-3.7) times more likely to be infected with chlamydia, gonorrhoea and HCV than the broader MSM population, respectively. CONCLUSION: Prevalence levels of STIs among MSW were significantly higher than the broader MSM population. Co-infection of HIV and STIs were prevalent among Chinese MSM. Integration of HIV and STIs healthcare and surveillance systems is essential in providing effective HIV/STIs preventive measures and treatments. TRIAL REGISTRATION: PROSPERO NO: CRD42013003721
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