19672 research outputs found
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A reduced graphene oxide-titanium dioxide nanocomposite based electrochemical aptasensor for rapid and sensitive detection of Salmonella enterica
No full textRecent foodborne outbreaks in multiple locations necessitate the continuous development of highly sensitive and specific biosensors that offer rapid detection of foodborne biological hazards. This work focuses on the development of a reduced graphene oxide‑titanium dioxide (rGO-TiO 2 ) nanocomposite based aptasensor to detect Salmonella enterica serovar Typhimurium. A label-free aptamer was immobilized on a rGO-TiO 2 nanocomposite matrix through electrostatic interactions. The changes in electrical conductivity on the electrode surface were evaluated using electroanalytical methods. DNA aptamer adsorbed on the rGO-TiO 2 surface bound to the bacterial cells at the electrode interface causing a physical barrier inhibiting the electron transfer. This interaction decreased the DPV signal of the electrode proportional to decreasing concentrations of the bacterial cells. The optimized aptasensor exhibited high sensitivity with a wide detection range (10 8 to 10 1 cfu mL −1 ), a low detection limit of 10 1 cfu mL −1 and good selectivity for Salmonella bacteria. This rGO-TiO 2 aptasensor is an excellent biosensing platform that offers a reliable, rapid and sensitive alternative for foodborne pathogen detection. © 201
Enhancement of simultaneous network reconfiguration and DG sizing via Hamming dataset approach and firefly algorithm
No full textDeregulation in the electrical industry has led utility companies to ensure high quality of power supply at the customer side. It is of utmost importance for utility companies to operate at maximum efficiency and minimise voltage deviation and power losses. Distributed network reconfiguration (DNR) and integration of distributed generation (DG) are commonly employed to mitigate power loss and voltage deviation. DNR is a complex combinatorial problem which requires radiality verification. Implicit radiality verification increases computational overhead and may lead to local optima. Whereas, improper selection of DG size poses direct consequences on the distribution network mainly on increased voltage deviation and power losses. Therefore, simultaneous optimal integration of DNR and DG is considered in this study to improve the overall performance of the distribution network. Explicit radiality verification is proposed based on Hamming dataset approach to significantly reduce the search space and the computational time, as well as to improve the quality of the solution. Subsequently, firefly algorithm is applied to attain near-optimal solution for NR and DG size. Four cases are considered to validate the effectiveness of the proposed technique including investigation on small, medium, and large-scale distribution network. The results show that the proposed technique is able to consistently attain near optimal-solutions. © The Institution of Engineering and Technology 2019
Q-switched fiber laser operating at 1 μm region with electron beam deposited titanium nanoparticles
No full textWe demonstrate the generation of Q-switched pulse train in Ytterbium-Doped Fiber Laser (YDFL) cavity by employing titanium (Ti) thin film as a passive saturable absorber (SA). The Ti-SA was fabricated by depositing Ti particles using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) thin film. Subsequently, a stable Q-switching pulse train was successfully generated by introducing the Ti-SA into a laser cavity. The laser generated a self-starting pulse train with repetition rate that is tunable from 42.96 to 98.12 kHz as the 980 nm pump power is increased from 122.5 mW to 197 mW. At 197 mW pump power, the laser produced a Q-switching pulse train with pulse duration and pulse energy of 3.95 μs and 57.48 nJ, respectively. This demonstration proves that Ti-SA is suitable for generating Q-switched fiber laser. Furthermore, it is easy and cheap to fabricate. © 2019 Elsevier Lt
Pure gold saturable absorber for generating Q-switching pulses at 2 µm in Thulium-doped fiber laser cavity
No full textWe experimentally demonstrate Q-switched Thulium-doped fiber laser operating at 1949.19 nm using pure gold saturable absorber (Au-SA) as a Q-switcher. The Au-SA was fabricated by depositing gold particles molecules using electron beam evaporation on the surface of a polyvinyl alcohol (PVA) film. Subsequently, stable Q-switched pulses were obtained within the 1552 nm pump power range from 343.1 to 467.3 mW, with repetition rate tuned from 11.7 kHz to 21.95 kHz. At 467.3 mW pump power, the TDFL produced pulses train with the pulse width of 2.6 μs and the maximum pulse energy of 89.8 nJ. These results propose that pure gold could be a promising saturable absorber for pulse generation in 2 µm wavelength region. © 201
Linearity improvement of differential CMOS low noise amplifier
No full textThis paper presents the linearity improvement of differential CMOS low noise amplifier integrated circuit using 0.13um CMOS technology. In this study, inductively degenerated common source topology is adopted for wireless LAN application. The linearity of the single-ended LNA was improved by using differential structures with optimum biasing technique. This technique achieved better LNA and linearity performance compare with single-ended structure. Simulation was made by using the cadence spectre RF tool. Consuming 5.8mA current at 1.2V supply voltage, the designed LNA exhibits S21 gain of 18.56 dB, noise figure (NF) of 1.85 dB, S11 of −27.63 dB, S22 of-34.33 dB, S12 of −37.09 dB and IIP3 of-7.79 dBm. © 2019, Institute of Advanced Engineering and Science. All rights reserved
Open-cell copper foam joining: joint strength and interfacial behaviour
No full textA copper (Cu) foam was brazed with Cu-4.0Sn-9.9Ni-7.8P filler foil for joint strength and interface analysis. Brazed 50 pores per inch (PPI) Cu foam yielded a maximum compressive strength of 14.4 MPa with a 127% increment compared to nonbrazed Cu foam. 15 PPI Cu foam produced a maximum shear strength of 2.7 MPa. Scanning electron microscopy showed that the thickness of the brazed seam decreased with increasing the Cu foam’s PPI. The formation of the Cu, Cu3P (P: phosphorus) and Ni3P (Ni: nickel) at the Cu/Cu foam interface was validated using energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction. EDX line scanning analysis revealed the diffusion of P and Ni into Cu foam, which took place via capillary force action. © 2019, © 2019 Institute of Materials, Minerals and Mining
Development of electronic medical records for clinical and research purposes: the breast cancer module using an implementation framework in a middle income country- Malaysia
No full textBackground: Advances in medical domain has led to an increase of clinical data production which offers enhancement opportunities for clinical research sector. In this paper, we propose to expand the scope of Electronic Medical Records in the University Malaya Medical Center (UMMC) using different techniques in establishing interoperability functions between multiple clinical departments involving diagnosis, screening and treatment of breast cancer and building automatic systems for clinical audits as well as for potential data mining to enhance clinical breast cancer research in the future. Results: Quality Implementation Framework (QIF) was adopted to develop the breast cancer module as part of the in-house EMR system used at UMMC, called i-Pesakit©. The completion of the i-Pesakit© Breast Cancer Module requires management of clinical data electronically, integration of clinical data from multiple internal clinical departments towards setting up of a research focused patient data governance model. The 14 QIF steps were performed in four main phases involved in this study which are (i) initial considerations regarding host setting, (ii) creating structure for implementation, (iii) ongoing structure once implementation begins, and (iv) improving future applications. The architectural framework of the module incorporates both clinical and research needs that comply to the Personal Data Protection Act. Conclusion: The completion of the UMMC i-Pesakit© Breast Cancer Module required populating EMR including management of clinical data access, establishing information technology and research focused governance model and integrating clinical data from multiple internal clinical departments. This multidisciplinary collaboration has enhanced the quality of data capture in clinical service, benefited hospital data monitoring, quality assurance, audit reporting and research data management, as well as a framework for implementing a responsive EMR for a clinical and research organization in a typical middle-income country setting. Future applications include establishing integration with external organization such as the National Registration Department for mortality data, reporting of institutional data for national cancer registry as well as data mining for clinical research. We believe that integration of multiple clinical visit data sources provides a more comprehensive, accurate and real-time update of clinical data to be used for epidemiological studies and audits. © 2018 The Author(s)
Frequency and Causes of Line of Sight Issues During Neurosurgical Procedures Using Optical Image-Guided Systems
No full textBackground: Navigation (image guidance) is an essential tool in modern neurosurgery, and most surgeons use an optical tracking system. Although the technology is accurate and reliable, one often is confronted by line of sight issues that interrupt the flow of an operation. There has been feedback on the matter, but the actual problem has not been accurately quantified, therefore making this the primary aim of this study. It is particularly important given that robotic technology is gradually making its way into neurosurgery and most of these devices depend on optical navigation when procedures are being conducted. Methods: In this study, the frequency and causes of line of sight issues is assessed using recordings of Navigation probe locations and its synchronised video recordings. Results: The mentioned experiment conducted for a series of 15 neurosurgical operations. This issue occured in all these surgeries except one. Maximum duration of issue presisting reached up to 56% of the navigation usage time. Conclusions: The arrangment of staff and equipment is a key factor in avoiding this issue. © 2018 Elsevier Inc
Effective leadership model: Needs analysis study of leaders in higher educational institutions of majlis amanah rakyat ('MARA')
No full textThis study aims to identify the views of leaders in advanced higher educational institutions. The value of the Leadership Model and the importance of leaders having effective leadership qualities in higher educational institutions of Majlis Amanah Rakyat ('MARA') will also be discussed. For the purpose of achieving the objectives of this study, structured interviews were done on ten leaders in higher educational institutions of MARA. The results of the interviews conducted were supported by the results of previous studies and a set of questionnaires were developed as instruments for the first round of the Delphi method. In addition, advancing leaders in higher educational institutions must implement the characteristics of effective leadership to form an excellent institution. © 2019 Primrose Hall Publishing Group
Impact of Lean Manufacturing Practices on Firms’ Sustainable Performance: Lean Culture as a Moderator
No full textNowadays, manufacturing firms are pressured by governments, non-governmental organizations and customers to operate in a sustainable manner. Although lean practices may provide environmental, social, and financial benefits to firms, their effect on sustainable performance is ambiguous. The aim of this study is to examine the effect of lean manufacturing practices on firms' environmental performance by considering lean culture as a moderator. Data were gathered through a survey of 187 manufacturing firms in Malaysia and were analyzed using the partial least squares technique. The results indicate that process and equipment, product design, supplier relationships, and customer relationships have a positive and significant effect on sustainable performance. It is also interesting to observe that lean culture positively moderated the effects of process and equipment and supplier relationships on sustainable performance. These results have important implications for enhancing the sustainable performance of manufacturing firms through lean manufacturing practices. © 2019 by the authors