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

Design of a radio frequency heated isothermal micro-trickle bed reactor

Abstract A near-isothermal micro-trickle bed reactor operated under radio frequency heating was developed. The reactor bed was packed with nickel ferrite micro-particles of 110 mu m diameter, generating heat by the application of RF field at 180 kHz. Hydrodynamics in a co-current configuration was analysed and heat transfer rates were determined at temperature ranging from 55 to 100 degrees C. A multi-zone reactor bed of several heating and catalytic zones was proposed in order to achieve near-isothermal operations. Exact positioning, number of the heating zones and length of the heating zones composed of a mixture of nickel ferrite and a catalyst were determined by solving a one dimensional model of heat transfer by conduction and convection. The conductive losses contributed up to 30% in the total thermal losses from the reactor. Three heating zones were required to obtain an isothermal length of 50 mm with a temperature non-uniformity of 2 K. A good agreement between the modelling and experimental results was obtained for temperature profiles of the reactor. (C) 2013 Elsevier B.V. All rights reserved

Phosphotungstic acid encapsulated in metal-organic framework as catalysts for carbohydrate dehydration to 5-hydroxymetrthylfurfural

MIL-101, a chromium-based metal–organic framework, is known for its very large pore size, large surface area and good stability. However, applications of this material in catalysis are still limited. 5-Hydroxymethylfurfural (HMF) has been considered a renewable chemical platform for the production of liquid fuels and fine chemicals. Phosphotungstic acid, H3PW12O40 (PTA), encapsulated in MIL-101 is evaluated as a potential catalyst for the selective dehydration of fructose and glucose to 5-hydroxymethylfurfural. The results demonstrate that PTA/MIL-101 is effective for HMF production from fructose in DMSO and can be reused. This is the first example of the application of a metal–organic framework in carbohydrate dehydration

Mechanochemical synthesis of TiO2/NiFe2O4 magnetic catalysts for operation under RF field

Composite NiFe2O4–TiO2 magnetic catalysts were prepared by mechanochemical synthesis from a mixture of titania supported nickel ferrite nanoparticles and P25 titania (Evonic). The former provides fast and efficient heating under radiofrequency field, while the latter serves as an active catalyst or catalyst support. The highest heating rate was observed over a catalyst prepared for a milling time of 30 min. The catalytic activity was measured over the sulfated composite catalysts in the condensation of aniline and 3-phenylbutyric acid in a stirred tank reactor and in a continuous RF heated flow reactor in the 140–170 °C range. The product yield of 47% was obtained over the sulfated P25 titania catalyst in the flow reactor

Magnetic actuation of catalytic microparticles for the enhancement of mass transfer rate in a flow reactor

The effect of periodic changes in particle velocity on mass transfer to the reacting surface of a magnetic particle with a diameter 225 μm in laminar flow has been investigated in a microfluidic reactor. The periodic particle motion in a fluid was investigated under a sinusoidal magnetic field generated by a quadrupole arrangement of electromagnets around the reactor. The effect of operating frequency of the rotating magnetic field, intensity of the magnetic field, and phase shift between the two sets of magnets on particle dynamics has been studied. Three particle motion modes have been observed depending on the frequency of the applied field. The mass transfer rate was estimated under steady velocity and variable velocity of the particle using a mass transfer correlation by Feng and Michaelides (2001). The validity of this correlation for the case of variable particle velocity has been confirmed with a 2D numerical model, describing actual hydrodynamics and mass transfer towards the particle surface. The mass transfer coefficient depends both on the mean particle velocity and the deviation of velocity from the mean value. The periodic movement with variable particle velocity reduces the mass transfer coefficient by 7.6% as compared to steady state motion with the same mean velocity

Ethylene methyl acrylate copolymer (EMA) assisted dispersion of few-layer graphene nanoplatelets (GNP) in poly(ethylene terephthalate) (PET)

The inclusion of ethylene methyl acrylate copolymer (EMA) during the melt mixing of composites of poly(ethylene terephthalate) (PET) and graphene nanoplatelets (GNP) results in increased melt viscosity and shear stresses acting on the molten composite. This is due to ester groups of the acrylates in the co-monomer unit of EMA reacting via transesterification with PET creating cross-linked structures, as confirmed by solid state 13C magic-angle-spinning, nuclear magnetic resonance spectroscopy (13C MAS NMR), Fourier transform infrared (FTIR) spectroscopy and, isothermal time sweep oscillatory rheology measurements. The increase in shear stresses assists the exfoliation of the GNP in the PET matrix, resulting in lower electrical and percolation threshold values. The electrical percolation decreased from a volume fraction of 0.017 to 0.005 GNP and an AC conductivity of the PET-GNP composite on inclusion of EMA as high as 10 S/m attained. The rheological percolation threshold value halved from a volume fraction of ~0.0237 to ~0.0117. Both EMA and GNP had a nucleating effect on the PET, as the crystallization temperature (Tc) of PET increased by > 20 °C and the crystalline content (Xc) by >25%

Structural and magnetic properties of Ni_1-xZn_xFe₂O₄ (x=0, 0.5 and 1) nanopowders prepared by sol-gel method

A series of nanostructured Ni–Zn ferrites Ni1−xZnxFe2O4 (x=0, 0.5 and 1) with a grain size from 24 to 65 nm have been prepared with a sol–gel method. The effect of composition and sintering temperature on morphology, magnetic properties, Curie temperature, specific heating rate at 295 kHz and hysteresis loss have been studied. The highest coercivity of 50 and 40 Oe, were obtained for NiFe2O4 and Ni0.5Zn0.5Fe2O4 samples with the grain size of 35 and 29 nm, respectively. The coercivity of Ni and Ni–Zn mixed ferrites decreased with temperature. The Bloch exponent was 1.5 for all samples. As the grain size increased, the Curie temperature of NiFe2O4 increased from 849 to 859 K. The highest saturation magnetization of 70 emu/g at 298 K and the highest specific heating rate of 1.6 K/s under radiofrequency heating at 295 kHz were observed over NiFe2O4 calcined at 1073 K. Both the magnitude of the hysteresis loss and the temperature dependence of the loss are influenced by the sintering temperature and composition

Gallium and tin exchanged Y zeolites for glucose isomerisation and 5-hydroxymethyl furfural production

This study demonstrates the use of gallium and tin modified Y zeolites as catalysts for the conversion of glucose into fructose, mannose and 5-Hydroxymethyl furfural. These catalysts can be synthesised via a simple and scalable procedure that uses commercially available Y zeolite. The catalysts were characterised by various techniques including elemental analysis, electron microscopy, nitrogen physisorption, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, solid state nuclear magnetic resonance spectroscopy and X-ray absorption near edge spectroscopy. It is found that tin containing Y zeolite generate a glucose conversion of 36 % and total product yield of 17 % in water. Meanwhile, gallium containing Y zeolite shows an HMF yield of 33 % when reactions were conducted in DMSO. The recyclability of tin and gallium containing Y zeolites were studied in DMSO and the activities of both materials were shown to remain stable. Furthermore, the spent catalysts can be regenerated via calcination in air