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Mutagenicity evaluation of Anastatica hierochuntica L. aqueous extract in vitro and in vivo
No full textAnastatica hierochuntica L. (A. hierochuntica), a folk medicinal plant, was evaluated for mutagenic potential via in vitro and in vivo assays. The in vitro assay was conducted according to modified Ames test, while the in vivo study was performed according to Organisation for Economic Co-operation and Development guideline for mammalian erythrocyte micronucleus assay. Four groups (n= 5 males and 5 females per group) Sprague Dawley rats were randomly chosen as the negative control, positive control (received a single intramuscular injection of cyclophosphamide 50 mg/kg), 1000 and, 2000 mg/kg A. hierochuntica aqueous extracts. All groups except the positive control were treated orally for three days. Findings of the in vitro assay showed mutagenic potential of AHAE at 0.04 and 0.2 mg/ml. However, no mutagenic effect was demonstrated in the in vivo study up to 2000 mg/kg. No significant reduction in the polychromatic and normochromatic erythrocytes ratio was noted in any of the groups. Meanwhile, high micronucleated polychromatic erythrocytes frequency was seen in cyclophosphamide-treated group only. These findings could perhaps be due to insufficient dosage of A. hierochuntica aqueous extracts to cause genetic damage on the bone marrow target cells. Further acute and chronic in vivo toxicity studies may be required to draw pertinent conclusion on the safety aspect of A. hierochuntica aqueous extracts consumption. Impact statement: In this paper, we report on the mutagenicity evaluation of Anastatica hierochuntica aqueous extract. This is a significant research in view of the popularity of this herb consumption by the people across the globe despite of limited scientific evidence on its toxicity potential. This study is intended to encourage more extensive related research in order to provide sufficient evidence and guidance for determining its safe dosage
An investigation into waterborne intumescent coating with different fillers for steel application
No full textPurpose – This study aims to discuss the modification and/or improvement of intumescent coating system by incorporating waterborne resin with an appropriate combination of flame-retardant additives and four different fillers, namely, TiO2, Al(OH)3, Mg(OH)2 and CaCO3. Design/methodology/approach – Coating mixtures are characterized using the Bunsen burner, thermogravimetric analysis, limiting oxygen index, scanning electron microscope, static immersion bath, Fourier transform infrared and adhesion tester. Findings – Results show that the combination of coating with CaCO3 filler significantly improved fire protection performance because of its thick char layer and the equilibrium temperature being 264°C. Char layer showed a uniform dense foam structure on micrograph and this formulation had adhesion strength of 2.13 MPa, which indicates effectiveness of the interface adhesion on substrate. Conversely, the combination of coating with Al (OH)3 exhibited highest oxygen index of 35 per cent, which resulted in excellent flammability resistance. Research limitations/implications – This paper discusses only the effect of mineral fillers on properties of intumescent coatings. Practical implications – In the modern design of building infrastructure, fire safety is significant for the protection of human life and assets. The application of intumescent coating in buildings is currently practiced because of its effect on material flammability during a fire. Originality/value – The analysis method to evaluate the performance of water-borne resin with different fillers is formulated, and it could be applied in all kinds of coatings and mixtures to be used as an effective fire protection system for steel constructions
Gender stereotypes and education: A comparative content analysis of Malaysian, Indonesian, Pakistani and Bangladeshi school textbooks
No full textUsing government secondary school English language textbooks from Malaysia, Indonesia, Pakistan and Bangladesh, we conducted a quantitative content analysis in order to identify gender stereotypes in school education. In total, 21 categories of exclusion and quality of representation were used to study gender stereotypes. Our analysis confirms a pro-male bias in textbooks: the aggregate female share is 40.4% in textual and pictorial indicators combined. Female occupations are mostly traditional and less prestigious while the characters are predominantly introverted and passive in terms of personality traits. Women are also shown to be mostly involved in domestic and in-door activities while men have a higher presence in professional roles. Systematic underrepresentation of females is evident regardless of whether we look at the text or pictures. A cross-country analysis shows that the female share in picture content is only 35.2% in Malaysia and Bangladesh. Overall, the proportion of female to male characters (text and pictures combined) is balanced in Malaysia and Indonesia (44.4% and 44.1% respectively) while this share is only 24.4% and 37.3% in Pakistani and Bangladeshi textbooks respectively. The finding of underrepresentation of women in Pakistani textbooks, in terms of quality and quantity, is robust to the selection of province-, grade- and subject-specific textbooks, as well as the range and type of categories used
Rice bran oil based biodiesel production using calcium oxide catalyst derived from Chicoreus brunneus shell
No full textEnvironmental pollution and the declining global supply of accessible fossil fuels are the key drivers of the search for alternative sources of energy. Biodiesel, a renewable liquid transport fuel, is commercially-produced using heterogeneous catalysts. Heterogeneous catalysts obtained from seashells appeared as promising alternatives thanks to their low preparation cost and increased efficiency in transesterification. In this study, shells from Chicoreus brunneus (known as Adusta murex) were calcined, hydrated, and dehydrated to produce CaO heterogeneous nanocatalyst for the transesterification of rice bran oil into biodiesel. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, surface area measurement (Brunauer-Emmett-Teller method), and X-ray diffraction were used to characterise the seashell-derived catalyst. The properties of the rice bran oil-derived biodiesel (acid value, calorific value, density, oxidation stability, and flash point) conformed to the American Society of Testing and Materials (ASTM) D6751 and European EN 14214 biodiesel standards, except for kinematic viscosity. Therefore, the impact of the parameters used for production of the CaO heterogeneous nanocatalyst (calcination temperature and time) and the transesterification reaction (catalyst loading and methanol to rice bran oil ratio) on the kinematic viscosity of RBO-derived biodiesel were determined. A model for the transesterification process was developed using a combination of artificial neural networking with ant colony optimisation. The model predicted that C. brunneus-derived CaO catalyst prepared at 1100 °C for 72 min could be used to produce biodiesel from rice bran oil with a minimum kinematic viscosity (4.42 mm2 s−1) confirming to both the ASTM D6751 and EN 14214 biodiesel standards in a transesterification reaction operating with a 35:1 methanol to rice bran oil molar ratio and 0.5 wt% catalyst mass
Untapped work capacity among old persons and their potential contributions to the “silver dividend” in Japan
No full textIn contemporary Japan, the utilization of healthy elderly persons in economic production is one of the most urgent policy matters. In this paper, we have measured the untapped work capacity of old persons, using the microdata gathered in the Japanese Study of Aging and Retirement (JSTAR), a longitudinal survey carried out on subjects aged 50–75. Our computed results show that the volume of untapped work capacity of the Japanese elderly aged 60–79 is vast, amounting to more than 11 million workers at present. We have also applied the computed results to the National Transfer Accounts (NTA) framework, and quantified the magnitude of the use of the untapped work capacity upon potential economic growth. The accumulated effect of the economic support ratio upon potential economic growth is substantial in the long term, generating a sizable amount of the so called “silver dividend”. We have also examined the issue of whether or not the use of untapped work capacity provided by old persons could affect the well-being of workers in other age groups. The regression results support the view that the substitutability between the selected age groups of the elderly and the young is negligible, so that the utilization of potential work capacity of elderly persons is unlikely to pose any serious threat to the employment opportunities of their young counterparts in Japan
Leisure time physical activity participation in individuals with spinal cord injury in Malaysia: barriers to exercise
No full textStudy design: Cross-sectional. Objectives: An epidemiological study describing leisure time physical activities (LTPA) and the associations of barriers, sociodemographic and injury characteristics to moderate-vigorous aerobic exercise participation among individuals with spinal cord injury (SCI) in a developing Southeast Asian country. Setting: SCI community in Malaysia. Methods: The study sample consisted of 70 participants with SCI. Questionnaires were distributed containing an abbreviated Physical Activity Scale for Individuals with Physical Disabilities (items 2–6) and the Barriers to Exercise Scale using a 5-tier Likert format. Statistical analyses were χ 2 tests, odds ratios, and binary forward stepwise logistic regression to assess the association and to predict factors related to participation in moderate-vigorous intensity aerobic exercise (items 4 and 5). Results: Seventy-three percent of the study sample did not participate in any form of moderate or vigorous LTPA. The top three barriers to undertaking LTPA (strongly agree and agree descriptors) were expensive exercise equipment (54%), pain (37%) and inaccessible facilities (36%). Participants over the age of 35 years, ethnicity, health concerns, perceiving exercise as difficult and indicating lack of transport were significantly different (p < 0.05) between participation and non-participation in moderate-vigorous aerobic exercise type of LTPA. Age, ethnicity, indicated health concerns and lack of transport were the significant predictors in likelihood of participating in moderate-vigorous LTPA (p < 0.1). Conclusion: The issues raised depicted barriers within the intrapersonal (health concerns, exercising is too difficult, pain while exercising, age more than 35), interpersonal (different ethnicity), community (expensive exercise equipment), and policy levels (lack of or poor access to transportation, inaccessible facilities) that prevent LTPA participation
Passively Q-switched Erbium-Doped Fiber Laser based on Graphene Oxide as Saturable Absorber
No full textIn this paper, passively Q-switched fiber laser is demonstrated and the laser output energy is stabilized by using 2.4m Erbium-doped fiber laser (EDFL) with a graphene oxide used as saturable absorber (GO-SA). According to the experimental results in the Q-switched configuration, the laser cavity emits a wavelength centered at 1,558.75nm, and by inserting the GO-SA into EDFL cavity, hence, the laser output energy around 1.68nJ with an FWHM pulse width of 2.3μs at 123.5kHz was achieved
Blended morphologies of plasmonic nanofluids for direct absorption applications
No full textDirect absorption solar collectors were introduced to overcome the limitations of conventional surface absorber collectors. The advances in nanotechnology accompanied with phenomenological discoveries at the nanoscale have allowed the appearance of plasmonic nanofluids, which utilize localized surface plasmon resonance phenomenon that multiplies the extinction efficiency of the plasmonic nanoparticle several times at the resonance wavelength. Silver nanoparticles exhibit a high intensity of the localized surface plasmon, which can be fine-tuned within the broadband 350–1200 nm by tailoring their shape, size and aspect ratio. In this paper, we have numerically investigated the effects of silver nanoparticles’ morphology on the localized surface plasmon resonance and on the extinction peaks. Numerical results allow determining the effective morphologies at every band of the solar spectrum. Thus, nanofluids composed of blended Ag nano-morphologies were designed, which can expand the absorbance over the entire solar spectrum. By means of the radiative transfer equation, we found that blended plasmonic nanofluids have the potential to raise the efficiency of the direct solar collector to more than 85% at a very low concentration below 0.001 wt%. Utilization of the blended plasmonic nanofluids are not limited to solar thermal and concentrated solar power applications, but also can be extended into the optical filters in PV/thermal applications
Random forest and Self Organizing Maps application for analysis of pediatric fracture healing time of the lower limb
No full textIn this study, we examined the lower limb fracture healing time in children using random forest (RF) and Self Organizing feature Maps (SOM) methods. The study sample was obtained from the pediatric orthopedic unit in University Malaya Medical Centre. Radiographs of long bones of lower limb fractures involving the femur, tibia and fibula from children ages 0–12 years, with ages recorded from the date and time of initial injury. Inputs assessment extracted from radiographic images included the following features: type of fracture, angulation of the fracture, contact area percentage of the fracture, age, gender, bone type, type of fracture, and number of bone involved. RF is initially used to rank the most important variables that effecting bone healing time. Then, SOM was applied for analysis of the relationship between the selected variables with fracture healing time. Due to the limitation of available dataset, leave one out technique was applied to enhance the reliability of RF. Results showed that age and contact area percentage of fracture were identified as the most important variables in explaining the fracture healing time. RF and SOM applications have not been reported in the field of pediatric orthopedics. We concluded that the combination of RF and SOM techniques can be used to assist in the analysis of pediatric fracture healing time efficiently
Ferroelectric polarization and pyroelectric activity of functionalized P(VDF-TrFE) thin film lead free nanocomposites
No full textThe ferroelectric, pyroelectric, and dielectric properties of 0–3 nanocomposite systems of ferroelectric (Bi0.5Na0.5)TiO3-(Bi0.5K0.5)TiO3-BaTiO3 ceramics with a vinylidene fluoride/trifluoethylene copolymer were investigated. It was observed that the interface effect between the polymer matrix and nanofiller improves the polarization response in nanocomposite. As a result, significant enhancements in remnant polarization of 130 mC/m2 and pyroelectric sensitivity of 90 μC/m2K are achieved compared to 85 mC/m2 and 26 μC/m2K for pure polymer matrix. Full ferroelectric polarization reversal in the nanocomposite system was supported by a displacement (D) – electric field (E) hysteresis loop and evidence of pyroelectric activity. This finding suggests that the local field plays an important key in facilitating the poling procedure. Therefore, the functional electrical properties of the nanocomposites can be significantly enhanced by controlling the permittivity and conductivity of the inorganic ferroelectric ceramic nanofiller to match the required parameters. Microscopic features of the ferroelectric polarization are also discussed in terms of a two-step switching process. The approach developed her open the way of rational design and assembly of lead free nanocomposite as flexible, light and high performance smart materials, satisfying various requirements for emerging applications