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Studies on the interaction of mononuclear metal(II) complexes of amino‑naphthoquinone with bio-macromolecules
No full textThree metal(II) complexes [CoLCl2], [CuLCl2] and [ZnL2Cl2] {L = 2‑chloro‑3‑((3‑dimethylamino)propylamino)naphthalene‑1,4‑dione} have been synthesized and characterized using analytical, thermal and spectral techniques (FT-IR, UV–Vis, ESR and ESI-MS). The structure of the L has been confirmed by single crystal XRD study. The complexes show good binding propensity to bovine serum albumin (BSA) having relatively higher binding constant values (104 M−1) than the ligand. Fluorescence spectral studies indicate that [CoLCl2] binds relatively stronger with CT DNA through intercalative mode, exhibiting higher binding constant (2.22 × 105 M−1). Agarose gel electrophoresis run on plasmid DNA (pUC18) prove that all the complexes showed efficient DNA cleavage via hydroxyl radical mechanism. The complexes were identified as potent anticancer agents against two human cancer cell lines (MCF7 and A549) by comparing with cisplatin. Co(II) complex demonstrated greater cytotoxicity against MCF7 and A549 cells with IC50 values at 19 and 22 μM, respectively
Effect of model simplification through manual reduction in number of surfaces on room acoustics simulation
No full textModel simplification is an important step in room modelling for acoustics simulation. Various simplification algorithms were previously suggested. However, they are highly demanding methods, which are more suitable for large complicated spaces. As this paper focused on small size open-plan office (OPO) spaces, basic modelling and manual simplification processes were used. The aim is to find the optimum level of model simplification through a manual reduction in number of surfaces. Parallel to this aim, the objective is to examine the effects of the change in model detail level on selected acoustical parameters in six OPOs. Construction of models started with the most detailed model. Simplified models were developed by gradually reducing the number of surfaces. Simulation on RT, STI and decay in SPL were done and compared to the measured data. The study found that models with up to 80% reduction in number of surfaces can still produce plausible simulation results. © 2019, University of Malaya. All rights reserved
Long‐term loss to follow‐up in the TREAT Asia HIV Observational Database ( TAHOD )
No full textObjectives: With earlier antiretroviral therapy (ART) initiation, time spent in HIV care is expected to increase. We aimed to investigate loss to follow-up (LTFU) in Asian patients who remained in care 5 years after ART initiation. Methods: Long-term LTFU was defined as LTFU occurring after 5 years on ART. LTFU was defined as (1) patients not seen in the previous 12 months; and (2) patients not seen in the previous 6 months. Factors associated with LTFU were analysed using competing risk regression. Results: Under the 12-month definition, the LTFU rate was 2.0 per 100 person-years (PY) [95% confidence interval (CI) 1.8–2.2 among 4889 patients included in the study. LTFU was associated with age > 50 years [sub-hazard ratio (SHR) 1.64; 95% CI 1.17–2.31] compared with 31–40 years, viral load ≥ 1000 copies/mL (SHR 1.86; 95% CI 1.16–2.97) compared with viral load < 1000 copies/mL, and hepatitis C coinfection (SHR 1.48; 95% CI 1.06–2.05). LTFU was less likely to occur in females, in individuals with higher CD4 counts, in those with self-reported adherence ≥ 95%, and in those living in high-income countries. The 6-month LTFU definition produced an incidence rate of 3.2 per 100 PY (95% CI 2.9–3.4 and had similar associations but with greater risks of LTFU for ART initiation in later years (2006–2009: SHR 2.38; 95% CI 1.93–2.94; and 2010–2011: SHR 4.26; 95% CI 3.17–5.73) compared with 2003–2005. Conclusions: The long-term LTFU rate in our cohort was low, with older age being associated with LTFU. The increased risk of LTFU with later years of ART initiation in the 6-month analysis, but not the 12-month analysis, implies that there was a possible move towards longer HIV clinic scheduling in Asia. © 2019 British HIV Associatio
Effect of tapering diameters with microbottle resonator for formaldehyde (CH2O) liquid sensing
No full textIn this study, we demonstrate the effect of the microbottle resonator (MBR) based on whispering gallery modes (WGMs) with two different diameters of tapered microfibre and its experiment with the formaldehyde (CH2O) liquid sensor. The MBR with the bottle diameter, Db, of 190 μm was categorized by many spectra of transmission modes. Then, the MBR was energized through two tapered microfibres with different diameters, 8 μm and 10 μm. Differences between the two tapered microfibres with the MBR were determined for different concentration levels of sensing liquid. In addition, p-values and stability levels of the two tapered microfibres were calculated. According to the comparison results, the 8 μm tapered microfiber has a much better competency than the 10 μm tapered microfiber when using the MBR. © 201
Income management of newly married couple: Case of the urban Malay community
No full textThe Department of Islamic Development Malaysia reported high divorce rates among Malays with a marriage duration of fewer than five years. It appears that financial hardship is the main cause. To address this problem, in-depth interviews on five newly married couples were conducted. The phenomenological method was used to expose the approach taken in managing household income. Findings showed that independent money management allocation system was the preferred practice. However, to meet religious claims, husbands also allocated housekeeping allowances to their wives. Besides, despite being married and having the responsibility of their own family, responsibility towards parents was not neglected. Economic instability is not a reason for these couples to ignore the needs of parents and other family members. Indeed, for Muslim couples, religion and cultures affected the management of household income. © 2019, Malaysian Consumer and Family Economics Association. All rights reserved
Leachate generation rate modeling using artificial intelligence algorithms aided by input optimization method for an MSW landfill
No full textLeachate is one of the main surface water pollution sources in Selangor State (SS), Malaysia. The prediction of leachate amounts is elementary in sustainable waste management and leachate treatment processes, before discharging to surrounding environment. In developing countries, the accurate evaluation of leachate generation rates has often considered a challenge due to the lack of reliable data and high measurement costs. Leachate generation is related to several factors, including meteorological data, waste generation rates, and landfill design conditions. The high variations in these factors lead to complicating leachate modeling processes. This study aims at identifying the key elements contributing to leachate production and developing various AI-based models to predict leachate generation rates. These models included Artificial Neural Network (ANN)-Multi-linear perceptron (MLP) with single and double hidden layers, and support vector machine (SVM) regression time series algorithms. Various performance measures were applied to evaluate the developed model’s accuracy. In this study, input optimization process showed that three inputs were acceptable for modeling the leachate generation rates, namely dumped waste quantity, rainfall level, and emanated gases. The initial performance analysis showed that ANN-MLP2 model—which applies two hidden layers—achieved the best performance, then followed by ANN-MLP1 model—which applies one hidden layer and three inputs—while SVM model gave the lowest performance. Ranges and frequency of relative error (RE%) also demonstrate that ANN-MLP models outperformed SVM models. Furthermore, low and peak flow criterion (LFC and PFC) assessment of leachate inflow values in ANN-MLP model with two hidden layers made more accurate values than other models. Since minimizing data collection and processing efforts as well as minimizing modeling complexity are critical in the hydrological modeling process, the applied input optimization process and the developed models in this study were able to provide a good performance in the modeling of leachate generation efficiently. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature
Mutual Coupling Reduction of a Wideband Circularly Polarized Microstrip MIMO Antenna
No full textMutual coupling (MC) between elements in an antenna array could significantly affect antenna performance, but this effect has rarely been reported for circularly polarized (CP) antennas. Therefore, this paper investigates a wideband CP multiple-input-multiple-output (MIMO) antenna operating between 1.8 and 2.6 GHz. A line patch was introduced between closely placed radiating elements ( 0.3\lambda ) to produce a high isolation between elements in the proposed antenna. The designed MIMO antenna has a wide impedance bandwidth, a wide axial ratio (AR) bandwidth, a very low MC ( \text{S}-{{21}} < -25 dB), a low envelop correlation coefficient (ECC < 0.01), a high diversity gain (DG 10 dB), and a realized gain of above 2 dB over the entire frequencies. The prototype of the proposed antenna geometry was fabricated and measured. A good agreement between the simulated and measured results was observed. © 2013 IEEE
Development of a Control System for a Domestic Grid-Connected Wind Turbine
No full textIn the United Kingdom (UK), homeowners who install grid connected renewable energy sources receive a threefold benefit. They can use the electricity generated by the source, they enjoy reduced household bills and they can also receive Feed-in Tariff payments from the UK government. Tariffs are paid for generating electricity and for exporting electricity back to the grid. Savings can be maximized by correctly managing the ratio of number of units consumed by the homeowner to the number of units exported to the grid. In order to achieve a low percentage export situation, it was postulated that a control system would be needed. This paper proposes a control system for a small wind turbine based on an Arduino Uno microcontroller. The system was designed and built in order to evaluate its effectiveness. Results showed that the control system was effective in ensuring a low percentage export. When immediate domestic demand was met, surplus electricity was diverted to a storage circuit. Only as a last resort, when domestic and storage demand was met, was electricity exported. A cost analysis of the system showed that having a control system incorporated as part of the wind turbine installation could lead to savings of more than 12,000 over the life of the product. Copyright © 2019 American Scientific Publishers All rights reserved
Applied anthropometric for wheelchair user in Malaysia
No full textUniversal design refers to wide range of ideas intended to establish facilities that are naturally applicable to small population like people with disabilities (PWDs), and subsequently, for older people, adults, and children. In that case, an anthropometric database for the Malaysian wheelchair users population should be initiated. A total of 52 participants took part in this study, which involved 41 males and 11 females from Malaysian wheelchair users with their ages ranging from 20 to 50 years old. 15 anthropometric dimensions were defined in designing workstations for wheelchair users. Interviews and surveys were conducted to investigate the problems faced by wheelchair users when using existing workstations in Malaysia. The result from t-test of SPSS software indicated that there are significant differences in the anthropometric dimensions between Malaysian wheelchair users population and Malaysian able-bodied population. The examples of sitting workstations designed based on wheelchair user preferences were also presented in this study. © 2018 Elsevier Lt
405 nm ultraviolet photodetector based on tungsten disulphide thin film grown by drop casting method
No full textIn this work, a tungsten disulphide or WS2 based heterojunction photodetector device is fabricated on top of Si substrate by simple drop casting. Raman shifts are observed at 350.16 and 419.36 cm−1, confirming the successful growth of the WS2 and the non-stoichiometric WS2 layers which are verified by energy-dispersive X-ray (EDX) spectroscopy. The device is characterized for its optoelectronic properties in the ultraviolet (UV) range of 405 nm. Current–voltage (I–V) measurement is performed to obtain the I–V curves of the photodiode under laser illumination at 30.219, 56.335, 80.457, 106.998 and 129.28 mW.cm−2. The photocurrent is found to be highly dependent on the laser power. The fabricated device has a high responsivity of 145.52 mA/W and a high detectivity of 1.248 × 1011 Jones for an incident laser power density of 129.28 mW.cm−2. These observed results are promising and indicate the viability of the proposed design for optoelectronic applications. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group