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A novel herringbone circularly polarized quasi lumped antenna array
No full textHerein, a series herringbone fed traveling wave quasi-lumped circularly polarized antenna array is presented. The proposed quasi-element antenna comprises a narrow strip inductor parallel to the interdigital capacitor. The inductor was placed at the center finger and shorted across the interdigital capacitor with pad capacitors connected at both ends of the structure. Circular polarization was achieved by feeding the quasi elements at the corners with a 90° phase difference along a travelling wave microstrip feed line. The proposed quasi-lumped element antenna has the potential to realize significant size reductions, and it will ultimately be lightweight, small volume, and inexpensive. The antenna characteristics of the array antenna, including return loss and radiation patterns, were characterized. The size of the antenna structure was 21 mm × 38 mm, allowing for potential use in wireless communication systems that use the 5 GHz ISM band. © ACE
Advanced lithium substituted hydroxyapatite nanoparticles for antimicrobial and hemolytic studies
No full textIn this study, pure hydroxyapatite (HAP) and lithium substituted hydroxyapatite (Li-HAP) nanoparticles were synthesized by a sonochemical synthesis process and investigated for their antimicrobial and hemolytic activities. The synthesized HAP and Li-HAP were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy. The XRD analysis confirmed the formation of the HAP phase both in the synthesized pure HAP and Li-HAP samples. It was also observed that the crystallite size was decreased in Li-HAP compared to pure HAP. FTIR analysis confirmed the presence of various functional groups (e.g. hydroxyl, phosphate etc. groups). Generally, hydroxyapatite has a rod and plate-like morphology. Upon doping, the rod and plate-like morphologies were modified to agglomerated needle-shaped HAP crystals. Antimicrobial, hemolytic and MTT studies were performed using human pathogens, human blood, and human bone cells, respectively, to investigate the biological activities of the synthesized HAP samples. The biological test results evidenced the biocompatibility and cytotoxicity of the HAP samples with better functionality of Li-HAP. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique
So, are early career researchers the harbingers of change?
No full textThis article provides the final results of a 3-year study that sought to discover whether early career researchers (ECRs) were the harbingers of change with respect to scholarly communications. Over a hundred science and social science ECRs from seven countries, spanning three continents, were depth-interviewed annually for 3 years (2016–2018) about their attitudes and behaviours with respect to 23 scholarly issues and activities (aspects). In order to provide an accessible overarching assessment of an extremely large and complex dataset, the interview data were categorized according to the strength and direction of change exhibited and the trends and points of interest raised. Results show that all ECRs have changed in one way or another, and a small minority has changed greatly in both attitude and practice and that collaboration and research impact are the scholarly aspects where most changes have occurred, and the greatest cause of change is not so much new technology as a change of jobs. © 2019 The Author(s). Learned Publishing © 2019 ALPSP
Electrospin-Coating of Paper: A Natural Extracellular Matrix Inspired Design of Scaffold
No full textPaper has recently found widespread applications in biomedical fields, especially as an alternative scaffolding material for cell cultures, owing to properties such as its fibrous nature, porosity and flexibility. However, paper on its own is not an optimal material for cell cultures as it lacks adhesion moieties specific to mammalian cells, and modifications such as hydrogel integration and chemical vapor deposition are necessary to make it a favorable scaffolding material. The present study focuses on modification of filter paper through electrospin-coating and dip-coating with polycaprolactone (PCL), a promising biomaterial in tissue engineering. Morphological analysis, evaluation of cell viability, alkaline phosphatase (ALP) activity and live/dead assays were conducted to study the potential of the modified paper-based scaffold. The results were compared to filter paper (FP) and electrospun PCL (ES-PCL) as reference samples. The results indicate that electrospin-coating paper is a simple and efficient way of modifying FP. It not only improves the morphology of the deposited electrospun layer through reduction of the fiber diameter by nearly 75%, but also greatly reduces the scaffold fabrication time compared to ES-PCL. The biochemical assays (Resazurin and ALP) indicate that electrospin-coated filter paper (ES-PCL/FP) provides significantly higher readings compared to all other groups. The live/dead results also show improved cell-distribution and cell-scaffold attachment all over the ES-PCL/FP. © 2019 by the authors
The impact of foreign ownership on return volatility, volume, and stock risks: Evidence from ASEAN countries
No full textThis paper aims to delve into the effect of foreign ownership on return volatility, volume, and risk of buying/holding stocks. It uses panel data from six ASEAN countries from 2007 to 2017. There are three primary findings. First, foreign ownership diminishes return volatility, particularly during and after a crisis. Second, it has a positive influence on the trading volume of a stock in the post-crisis, nonetheless negative during a crisis. Third, it reduces the asset and equity risks. However, these beneficial findings could be uniquely different in other ASEAN member economies. In conclusion, the benefits of foreign ownership outweigh the downside to it. © 201
Evaluation of radon concentration in irrigation and drinking waters from the eastern part of Oman and estimation of effective doses to Omanis
No full textThe present study concerns measurement of the radon concentration in drinking and irrigation waters obtained from the eastern part of Oman, in particular in regard to water quality assessment of the region. The samples were collected from different places covering most types of water sources in the region. A passive and time-integrated track etch detector (LR-115 type II) combined with a high-resolution optical microscope has been used to obtain the radon concentration in the studied samples. Values of dissolved radon in water varied among the water sources; the highest concentration of radon was found to be 363 Bq m-3 in a drinking water sample while well water used for irrigation showed the lowest value, at 140 Bq m-3. Measured data for all water sources are below the permissible limit of 11.1 kBq m-3 recommended by the US-EPA. Annual effective doses for the studied samples were in the range 0.38-0.99 μSv y-1 which is significantly less than the action level recommended by the WHO (0.1 mSv y-1), indicating that the water sources in the Jalan BBH region of Oman are safe to use. The obtained data may serve as a reference for any future radiological study of the waterbody of this region. © 2019 The Author(s)
Squamous Cell Carcinoma Biomarker Sensing on a Strontium Oxide-Modified Interdigitated Electrode Surface for the Diagnosis of Cervical Cancer
Get PDFCervical cancer is a life-threatening complication, appearing as the uncontrolled growth of abnormal cells in the lining of the cervix. Every year, increasing numbers of cervical cancer cases are reported worldwide. Different identification strategies were proposed to detect cervical cancer at the earlier stages using various biomarkers. Squamous cell carcinoma antigen (SCC-Ag) is one of the potential biomarkers for this diagnosis. Nanomaterial-based detection systems were shown to be efficient with different clinical biomarkers. In this study, we have demonstrated strontium oxide-modified interdigitated electrode (IDE) fabrication by the sol-gel method and characterized by scanning electron microscopy and high-power microscopy. Analysis of the bare devices indicated the reproducibility with the fabrication, and further pH scouting on the device revealed that the reliability of the working pH ranges from 3 to 9. The sensing surface was tested to detect SCC-Ag against its specific antibody; the detection limit was found to be 10 pM, and the sensitivity was in the range between 1 and 10 pM as calculated by 3σ. The specificity experiment was carried out using major proteins from human serum, such as albumin and globulin. SCC-Ag was shown to be selectively detected on the strontium oxide-modified IDE surface. © 2019 Hongqing Wang et al
Transcriptional profiling of coaggregation interactions between Streptococcus gordonii and Veillonella parvula by Dual RNA-Seq
No full textMany oral bacteria form macroscopic clumps known as coaggregates when mixed with a different species. It is thought that these cell-cell interactions are critical for the formation of mixed-species biofilms such as dental plaque. Here, we assessed the impact of coaggregation between two key initial colonizers of dental plaque, Streptococcus gordonii and Veillonella parvula, on gene expression in each partner. These species were shown to coaggregate in buffer or human saliva. To monitor gene regulation, coaggregates were formed in human saliva and, after 30 minutes, whole-transcriptomes were extracted for sequencing and Dual RNA-Seq analysis. In total, 272 genes were regulated in V. parvula, including 39 genes in oxidoreductase processes. In S. gordonii, there was a high degree of inter-sample variation. Nevertheless, 69 genes were identified as potentially regulated by coaggregation, including two phosphotransferase system transporters and several other genes involved in carbohydrate metabolism. Overall, these data indicate that responses of V. parvula to coaggregation with S. gordonii are dominated by oxidative stress-related processes, whereas S. gordonii responses are more focussed on carbohydrate metabolism. We hypothesize that these responses may reflect changes in the local microenvironment in biofilms when S. gordonii or V. parvula immigrate into the system. © 2019, The Author(s)
Diversity and abundance of beetle at Kuala Kelapor, National Park, Malaysia
No full textNational Park is one of the oldest rainforests found in South-east Asia andit hasa very complex ecosystem. The objective of this study was to preparean inventory on beetle abundance and diversity at Kuala Kelapor National Park, Malaysia. Beetles were sample during pitfall traps, Malaise traps and light traps at five different trails in April 2015. This study successfully recorded709 individuals of beetles from 93 different species belonging to 26 different families. The most abundant species was Coccotrypes sp. 1, followed by Coccotrypes sp. 2 and Aetheomorpha sp. 1. The abundant beetle families were Curculionidae, Chrysomelidae and Scarabaeidae. Light traps and pitfall traps showed almost identical number of beetles collected, while Malaise traps recorded of107 individuals. Higher number of beetles were collected from Trail 3, followed by Trail 1 and base camp. The Shannon diversity index, Simpson diversity index and Fisher alpha diversity showed higher diversity values, which suggests that National Park accommodates a high diversity of beetles. Abundance is measured using Margalef index and Menhinick indices, showed values of 13.88 and 3.47, respectively. This information could be used as an initial step to analyze the potential use of beetles as a bioindicator group in Malaysia and climate change studies. © 2019, Universiti Kebangsaan Malaysia Press. All rights reserved
Big Data in Motion: A Vehicle-Assisted Urban Computing Framework for Smart Cities
No full textSmart cities are envisioned to facilitate the well-being of the society through efficient management of the Internet of Things resources and the data produced by these resources. However, the enormous number of such devices would result in unprecedented growth in data, creating capacity issues related to the acquisition, transfer from one location to another, storage, and finally the analysis. The traditional networks are not sufficient to support the transfer of this huge amount of data, proving to be costly both in terms of delay and energy consumption. Alternative means of data transfers are thus required to support this big data produced by smart cities. In this paper, we have proposed an efficient data-Transfer framework based on volunteer vehicles whereby we employ vehicles to carry data in the direction of the destination. The framework promotes self-belonging, social awareness, and energy conservation through urban computing encouraging participation by citizens. The proposed framework can also facilitate the research community to benchmark their own route selection algorithms easily. Further, we performed an extensive evaluation of the proposed framework based on realistic models of vehicles, routes, data-spots, data chunks to be transmitted and the energy consumed. Our results show the efficacy of the proposed data transfer framework as the energy consumed through vehicles is significantly less than that consumed by transmission over the Internet thereby reducing the carbon footprint. The results also offer several insights into the optimal configuration of a vehicular data transfer network based on analysis of delay, energy consumption, and data-spot utilization. © 2013 IEEE