A non-Newtonian fluid flow model for blood flow through a catheterized artery—Steady flow

AbstractIn this paper the effects catheterization and non-Newtonian nature of blood in small arteries of diameter less than 100μm, on velocity, flow resistance and wall shear stress are analyzed mathematically by modeling blood as a Herschel–Bulkley fluid with parameters n and θ and the artery and catheter by coaxial rigid circular cylinders. The influence of the catheter radius and the yield stress of the fluid on the yield plane locations, velocity distributions, flow rate, wall shear stress and frictional resistance are investigated assuming the flow to be steady. It is shown that the velocity decreases as the yield stress increases for given values of other parameters. The frictional resistance as well as the wall shear stress increases with increasing yield stress, whereas the frictional resistance increases and the wall shear stress decreases with increasing catheter radius ratio k (catheter radius to vessel radius). For the range of catheter radius ratio 0.3–0.6, in smaller arteries where blood is modeled by Herschel–Bulkley fluid with yield stress θ=0.1, the resistance increases by a factor 3.98–21.12 for n=0.95 and by a factor 4.35–25.09 for n=1.05. When θ=0.3, these factors are 7.47–124.6 when n=0.95 and 8.97–247.76 when n=1.05

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

A Numerical Study of Dissipative Chemically Reactive Radiative MHD Flow Past a Vertical Cone with Nonuniform Mass Flux

A computational model is presented to explore the properties of heat source, chemically reacting radiative, viscous dissipative MHD flow of an incompressible viscous fluid past an upright cone under inhomogeneous mass flux. A numerical study has been carried out to explore the mass flux features with the help of Crank-Nicolson finite difference scheme. This investigation reveals the influence of distinct significant parameters and the obtained outputs for the transient momentum, temperature and concentration distribution near the boundary layer is discussed and portrayed graphically for the active parameters such as the Schmidt number Sc, thermal radiation Rd, viscous dissipation parameter ɛ, chemical reaction parameter λ, MHD parameter M and heat generation parameter Δ. The significant effect of parameters on shear stress, heat and mass transfer rates are also illustrated

New catalysts for clean technology

The preparation, characterisation and catalytic performance of both bimetallic nanoparticles and chiral homogeneous catalysts anchored along the interior walls of mesoporous silica (MCM-41) are described. The bimetallic nanoparticles are prepared from Ru6Pd6 and Ru6CSn carbonyl clusters and the resulting MCM derivatives are characterised by a number of methods, including EXAFS, FTIR and STEM. The solvent-free hydrogenation of naphthalene and cyclic polyenes using these catalysts are described, with the Ru6CSn based catalyst giving a 90% selectivity for the corresponding monoenes while the Ru6Pd6 produces the fully hydrogenated product in high yield. The homogeneous catalysts 1-[-(R)-1'-2-bis((diphenylphosphino)ferrocenyl]ethyl-N-N'-dimethylethylenediamine palladium dichloride was heterogenised by anchoring along the inside walls of MCM-41. The catalysed reaction between cinnamylacetate and benzylamine was studied and the catalyst produced 51% of the branched chain product possibly with 100%ee