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Clustering and Tracking the Stability of Biological CVD Risk Factors in Adolescents: The Malaysian Health and Adolescents Longitudinal Research Team Study (MyHeARTs)
No full textBackground: Cardiovascular disease (CVD) risk factors tend to cluster and progress from adolescence to young adulthood. Reliable and meaningful clustering of CVD risk factors is essential to circumvent loss of information. Tracking adverse and high-risk profiles of adolescents is hoped to curb CVD progression later in life. The study aims to investigate the clustering of biological CVD risk factor among adolescents in Malaysia and the transitions between clusters over time. Method: The Malaysian Health and Adolescents Longitudinal Research Team study (MyHeARTs) examined school students aged 13 in 2012 and re-examined them in 2014 and 2016. In a two-stage stratified cluster sampling, 1,361 students were recruited, of which, 1,320 had complete data. In the follow-up, there were 881 and 637 students in 2014 and in 2016, respectively. Pearson's correlation coefficients were used to identify and remove highly correlated CVD risk factors. All risk factors were standardized into z-scores. The hierarchical and non-hierarchical (k-means) cluster analyses were used to classify students into high, medium and low risk clusters in each screening year. The tracking and stability of cluster transitions through cross-classification were enumerated with Pearson's inter-age correlations and percentages. Results: Three significant clusters of high, medium and low risk groups were derived from the clustering of eight biological CVD risk factors. The transitions between risk clusters from one screening year to the other were categorized as either stagnant, improved or adverse. The number of students who had adverse transitions increased from 15.5% (13–15 year) to 19.5% (15–17 year), 13.8 to 18.2% among the girls and 19.9 to 22.8% among the boys. For girls, the number of them who remained at high risk over the two transition periods were about the same (13.6 vs. 13.8%) whereas for boys, the percentage reduced from 14.6 to 12.3%. Conclusion: Over time, more than 12% of adolescents remained in the high risk cluster. There were sizable adverse transitions over time as more adolescents appear to be shifting toward an increased risk of having CVD. Collaborative and constant measures should be taken by parents, school, health promotion boards and policy makers to curb the multiplicative effect of clustering CVD risk factors among adolescents. © Copyright © 2020 Thangiah, Chinna, Su, Jalaludin, Al-Sadat and Majid
Readiness and understanding of technical vocational education and training (TVET) lecturers in the integration of industrial revolution 4.0
No full textThis study aims to determine the readiness and understanding of Technical Vocational Education and Training (TVET) lecturers in the implementation of Industrial Revolution 4.0 (IR4.0). A total of 203 TVET lecturers in Malaysia were involved in this study, which also used descriptive and inferential statistics. Findings reveal a high level of readiness, understanding and implementation of IR 4.0 amongst the TVET lecturers. A significant relationship likewise exists amongst readiness, understanding and implementation of IR4.0. Findings also show that the TVET lecturers' understanding is a mediator of the relationship between readiness and implementation of IR4.0. Lastly, results imply that the lecturers can further enhance their effort in implementing IR4.0 to achieve the Mission of 2020. © 2020 Primrose Hall Publishing Group
Narrow bandwidth optimization using a polymer microring resonator in a thulium–holmium fiber laser cavity
No full textA thulium–holmium fiber (THDF) laser cavity has been demonstrated with a SU-8 polymer microring resonator (PMRR) in the cavity. The PMRR has a 500μm radius and fabricated using the lithography method, with the SU-8 polymer acting as a host material. The butt coupling method was used for the horizontal coupling of light from a ultra-high numerical aperture (UHNA) fiber to the polymer waveguide. Lasing in the cavity without the PMRR is obtained at a center wavelength of 1.910μm, 1.869μm when the PMMR is inserted into the cavity. A maximum power of -5 dBm was extracted from the laser oscillator, and the laser linewidth was measured to be ∼26.6 kHz by radio-frequency spectrum analyzer analysis. The PMRR was able to generate an output with a free spectral range of 0.79μm at a frequency of 59.25 GHz. © 2020 Elsevier B.V
Synthesis of a series of novel dihydro-[1,2,4]triazolo [1,5-a]pyrimidine scaffolds: Dual solvent-catalyst activity of a low viscous and acid-functionalized ionic liquid
No full textThe viscosity of neat ionic liquids is very important for their application in organic synthesis as a solvent because most of the neat ionic liquids are very viscous, which would result in the less efficient mass transfer of reactants. In the present study, a series of novel dihydro-[1,2,4]triazolo[1,5-a]pyrimidines were prepared using a low viscous and acid-functionalized ionic liquid. Our results showed that new ionic liquid can act as a green solvent and acid catalyst due to low viscosity and acid functionality. The products were simply extracted and the ionic liquid was retrieved several times without reducing its catalytic efficiency. The current application of TMDPS in the one-pot multicomponent reactions as dual solvent-catalyst highlights the importance of low viscous acid-functionalized ionic liquids in organic synthesis, and we hope that further research will be conducted in the future to finding other applications of TMDPS with promising results. © 2020, © 2020 Taylor & Francis Group, LLC
Arene diazonium saccharin intermediates: a greener and cost-effective alternative method for the preparation of aryl iodide
No full textIn the current protocol, the arene diazonium saccharin derivatives were initially produced from various substituted aromatic amines; subsequently, these intermediates were treated with a greener organic iodide for the preparation of the aryl iodide. We tried to choose low-cost, commercially available, biodegradable, recoverable, ecofriendly, and safe reagents and solvents. The arene diazonium saccharin intermediates could be stored in the liquid phase into a refrigerator for a long time with no significant loss activity. The outstanding merits of the current protocol (a) included the partial recovering of saccharin and tetraethylammonium salt, (b) reduce the use of solvents and the reaction steps due to eliminating separation and purification of intermediates, (c) good yield of the sterically hindered substrates, and (d) avoid the generation of heavy metal or corrosive waste. © TÜBİTA
Production of microalgal biochar and reducing sugar using wet torrefaction with microwave-assisted heating and acid hydrolysis pretreatment
No full textThis study employed the microwave-assisted acid hydrolysis pretreatment using wet torrefaction on two indigenous microalgae, Chlorella vulgaris ESP-31 and Chlorella sp. GD with different biomass composition to investigate the yields of solid biochar and total reducing sugar in the liquid hydrolysate. Operating conditions at low temperatures (160, 170 °C) with short holding time (5, 10 min) under several concentrations of diluted acid medium (0, 0.1 and 0.2 M) were carried out to investigate the torrefaction severity effects towards the properties of the solid and liquid products. The highest biochar yields of 54.5% and 74.6% are obtained from C. vulgaris ESP-31 and Chlorella sp. GD, respectively under the wet torrefaction conditions with an improvement in the properties for fuel and value-added environmental application. The highest total reducing sugar concentration of 98.11 g/L and 12.08 g/L are obtained in C. vulgaris ESP-31 and Chlorella sp. GD liquid hydrolysates, respectively after acid hydrolysis pretreatment. With the co-production of high total reducing sugar in the liquid hydrolysate that can be utilized for bioethanol production and solid biochar as another value-added product, the acid hydrolysis pretreatment using wet torrefaction can be one of the conversion technologies towards the application of renewable energy production. © 2020 Elsevier Lt
Human Papillomavirus (HPV) Vaccine Uptake and the Willingness to Receive the HPV Vaccination among Female College Students in China: A Multicenter Study
No full textBackground: This study aimed to determine human papillomavirus (HPV) vaccine uptake and willingness to receive HPV vaccination among female college students, in China, and its associated factors. Methods: An online cross‐sectional survey of female college students across the eastern, central, and western regions of China was undertaken between April and September 2019. Partial least squares structural equation modeling (PLS‐SEM) was used to examine factors associated with the HPV vaccine uptake and willingness to receive the HPV vaccine. Results: Among the total 4220 students who participated in this study, 11.0% reported having been vaccinated against HPV. There are direct effects of indicators of higher socioeconomic status, older age (β = 0.084 and p = 0.006), and geographical region (residing in Eastern China, β = 0.033, and p = 0.024) on HPV vaccine uptake. Higher knowledge (β = 0.062 and p < 0.000) and perceived susceptibility (β = 0.043 and p = 0.002) were also predictors of HPV vaccine uptake. Of those who had not received the HPV vaccine, 53.5% expressed a willingness to do so. Likewise, social economic status indicators were associated with the willingness to receive the HPV vaccine. Total knowledge score (β = 0.138 and p < 0.001), both perceived susceptibility (β = 0.092 and p < 0.001) and perceived benefit (β = 0.088 and p < 0.001), and sexual experience (β = 0.041 and p = 0.007) had a positive and significant direct effect on the willingness to receive the HPV vaccine, while perceived barriers (β = −0.071 and p < 0.001) had a negative effect on the willingness to receive the HPV vaccine. Conclusions: Geographical region and socioeconomic disparities in the HPV vaccination uptake rate and willingness to receive the HPV vaccine provide valuable information for public health planning that aims to improve vaccination rates in underserved areas in China. The influence of knowledge and perceptions of HPV vaccination suggests the importance of communication for HPV immunization. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
Strain-tunable electronic and magnetic properties of two-dimensional gallium nitride with vacancy defects
No full textBased on density functional theory, we have investigated the effects of in-plane biaxial strain on the electronic and magnetic properties of the two-dimensional GaN (2D GaN) with Ga- (VGa) or N-vacancy (VN). We considered two different levels of vacancy concentration, i.e., θ = 1 / 62 and θ = 1 / 34. While the pristine GaN 2D structures are intrinsically semiconducting, the 2D GaN with VGa defects under tensile/compressive biaxial strains is metallic, except at a high compressive strain of 6%. In addition, the 2D GaN exhibits a strain-tunable magnetic property by introducing the VGa defects, where the magnetic moment can be modulated by applying a biaxial strain on the material. A compressive strain larger than 2% tends to suppress the magnetic effect. A drastic reduction of the total magnetization from 2.21 μ B to 0.16 μ B is clearly visible for a lower VGa concentration of θ = 1 / 62. On the other hand, the 2D GaN with VN defects is nonmagnetic, and this behavior is not affected by the biaxial strain. © 2020 Author(s)
An investigation of the stirring duration effect on synthesized graphene oxide for dye-sensitized solar cells
No full textThis study investigates the effects of stirring duration on the synthesis of graphene oxide (GO) using an improved Hummers’ method. Various samples are examined under different stirring durations (20, 40, 60, 72, and 80 h). The synthesized GO samples are evaluated through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. The GO sample with 72 h stirring duration (GO72) has the highest d-spacing in the XRD results, highest atomic percentage of oxygen in EDX (49.57%), highest intensity of oxygen functional group in FTIR spectra, and highest intensity ratio in Raman analysis (ID/IG = 0.756). Results show that GO72 with continuous stirring has the highest degree of oxidation among other samples. Electrochemical impedance spectroscopy analysis shows that GO72–titanium dioxide (TiO2) exhibits smaller charge transfer resistance and higher electron lifetime compared with the TiO2-based photoanode. The GO72 sample incorporating TiO2 nanocomposites achieves 6.25% photoconversion efficiency, indicating an increase of more than twice than that of the mesoporous TiO2 sample. This condition is fully attributed to the efficient absorption rate of nanocomposites and the reduction of the recombination rate of TiO2 by GO in dye-sensitized solar cells. © 2020 Yau et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Is there conflation? An acoustic analysis of vowels in Japanese English
No full textThis article examines whether conflation, a term introduced by Nihalani, occurs among English vowels produced by four Japanese native speakers reading a short English text. On the basis of perceptual, acoustic, and statistical methods, it is argued that conflation is not key to understanding the structure of vowels in Japanese English (JE). Having inspected vowel variants, we conclude the following. First, since conflation is not guaranteed, singular emphasis on suprasegmental features is untenable. Second, vowel space in JE tends to be centralized. As a result, speakers have more difficulty producing open back vowels. Third, the centralized vowel [a], substituted for five vowels (/æ/, /ə/, /ʌ/, /ɜ/, /ɑ/), is not statistically speaking a single sound. Fourth, JE speakers produce near-native vowels to different degrees. Statistical test results showed no significant difference between the pronunciation of the open-mid vowel [ʌ] produced by JE speakers and an American English speaker. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group