The effect of Al(NO3)3 concentration on the formation of AuNPs using low temperature hydrothermal reaction for memory application

Distribution of gold nanoparticles (AuNPs) on a substrate becomes crucial in nanotechnology applications. This work describes a route to fabricate AuNPs directly on silicon substrates by using an aluminum template in hydrothermal reaction at 80°C for 1 h. The effect of aluminum nitrate (Al(NO3)3) concentration in the hydrothermal bath was investigated. The properties of AuNPs were studied using field-emission scanning electron microscope (FESEM), x-ray diffractometer (XRD) and semiconductor characterization system (SCS). Two distinct sizes of AuNPs were observed by FESEM. XRD analysis proved the formation of AuNPs directly on the substrate. AuNPs were embedded between polymethylsilsesquioxane (PMSSQ) in order to investigate their effect on memory properties. The sample grown in 0.1 M Al(NO3)3 exhibited the largest hysteresis window (2.6 V) and the lowest Vth (2.2 V) to turn ‘ON’ the memory device. This indicated that good distribution of FCC structure AuNPs with 80±4 nm and 42±7 nm of large and small particles produced better charge storage capability. Charge transport mechanisms of AuNPs embedded in PMSSQ were explained in details whereby electrons from Si are transported across the barrier by thermionic effects via field-assisted lowering at the Si-PMSSQ interface with the combination of the Schottky and Poole Frenkel emission effect in Region 1. Trapped charge limited current (TCLC) and space charge limited current (SCLC) transport mechanism occurred in Region 2 and Region 3

Genotoxic effect of zinc and cadmium following single and binary mixture exposures in tilapia (Oreochromis niloticus) using micronucleus test

The aim of this study was to investigate the genotoxicity effect of Cd and Zn and their binary mixtures in tilapia fish Oreochromis niloticus using the micronucleus test. Two cytogenetic end points were considered; the frequencies of micronucleated cells and nuclear abnormalities. Fishes were exposed to 4.63 mg/L Cd, 7.50 mg/L Zn and 4.63 mg/L Cd + 7.50 mg/L Zn mixture for the period of 24, 48, 72 and 96 h. The results showed that the frequencies of micronuclei and nuclear abnormalities in the erythrocyte were significantly increased in all groups of treatments when compared with the control group (0 exposures). In addition, the highest frequencies of micronucleated and nuclear abnormalities were obtained after 48 h exposure in almost all cases (except in the mixture of Cd+Zn) and decreased after 72 and 96 h exposure. Frequencies of micronuclei and erythrocytes with nuclear abnormalities exposed to a mixture of Cd+Zn in O. niloticus were always lower at all-time points (after 24, 48, 72 and 96 h) than that of a single Cd and Zn exposure. Therefore, the study demonstrated that the genotoxic potential of these metal compounds and the simultaneous treatment of Cd and Zn suggest the presence of antagonistic interactions

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

Phytosociology of aquilaria malaccensis lamk. And its communities from a tropical forest reserve in Peninsular Malaysia

A phytosociological study on the floristic and vegetation communities of Aquilaria malaccensis was carried out in Sungai Udang Forest Reserve, Malacca, Malaysia. The main objectives of this study were to identify, characterize and classify the Aquilaria malaccensis communities which were naturally distributed in the Sungai Udang Forest Reserve. A total of 25 plots (40 m x 20 m) in size were constructed according to the line transect method. The vegetation sampling and data analysis were done. A total of 80 species belonging to 79 genera and 40 families were found from all the 25 plots in Sungai Udang Forest Reserve. The most abundant family was the Euphorbiaceae with 220 individual trees, followed by Myrtaceae and Anacardiaceae representing 212 and 197 individual trees, respectively. A community which was Aquilaria malaccensis - Artocarpus rigidus community with two new sub-community known as Palaquium gutta sub-community and Barringtonia racemosa sub-community were identified on the basis of statistical and phytosociological analyses. These community and sub-community also showed preference on different geographical and environmental factors such as soils and local relief. This study is useful in providing more information on the growth response of the mixed dipterocarp forest in the development of proper forest management

Separation of hydridocarbonyltris(triphenylphosphine) rhodium (I)catalyst using solvent resistant nanofiltration membrane

An investigation was conducted into the nanofiltration of rhodium tris(triphenyl-phosphine) [HRh(CO)(PPh3)3] catalyst used in the hydroformylation of olefins. The large size of the catalyst (>400 Da) – relative to other components of the reaction provides the opportunity for a membrane separation based on retention of the catalyst species while permeating the solvent. The compatibility of the solvent-polyimide membrane (STARMEMTM 122 and STARMEMTM 240) combinations was assessed in terms of the membrane stability in solvent plus non-zero solvent flux at 2.0 MPa. The morphology of the membrane was studied by field emission scanning electron microscopy (FESEM). The solvent flux and membrane rejection of HRh(CO)(PPh3)3 was then determined for the catalyst-solvent-membrane combination in a dead-end pressure cell. Good HRh(CO)(PPh3)3 rejection (>0.93) coupled with good solvent fluxes (>72 L/m2h1 at 2.0 MPa) were obtained in one of the systems tested. The effect of pressure and catalyst concentration on the solvent flux and catalyst rejection was conducted. Increasing pressure substantially improved both solvent flux and catalyst rejection, while increasing catalyst concentration was found to be beneficial in terms of substantial increases in catalyst rejection without significantly affecting the solvent flux

The health profile of Malaysian adolescents from 1990-2015: a systematic analysis of burden of disease data

Abstracts of Poster SymposiaSuraya Abdul Razak, Susan M. Sawyer, George C. Patton, Karly Cini, Peter S. Azzopard

Effects of soya bean extract, bisphenol A and 17 beta-estradiol on the testis and circulating levels of testosterone and estradiol among peripubertal juvenile male sprague-dawley rats

In this study, juvenile male Sprague-Dawley rats (PND 22) were fed with soya extract, bisphenol A, and 17 beta-estradiol, respectively by oral gavage to determine the potential effect on the morphology of their reproductive organs and their hormonal levels. After three weeks of treatment (PND 43), all animals were sacrificed and the blood and testes were collected. All the three treatment groups showed histological differences in testes morphology compared to the control. Animals treated with soya extract and bisphenol A showed a decrease in circulating estradiol levels while animals treated with 17 beta-estradiol showed elevated circulating levels of estradiol. Only the animals treated with soya extract showed elevated levels of circulating testosterone. The results of the present study showed that, soya extract, bisphenol A, and 17 beta-estradiol can alter the histological structure of the testes and influence circulating steroidal hormone levels