175 research outputs found

    Collagen-calcium alginate film dressing with therapeutic ultrasound to treat open wound in rats

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    About 24 healthy female Sprague-Dawley rats weighing between 300-350 g were used in this study over a 20 day period. They were allocated randomly into 4 groups of 6 animals each. After the creation of 2x2 cm open wound, group 1 was control treated with Gentamycin ointment. Groups 2-4 were treated with Therapeutic ultrasound massage, collagen-calcium alginate film and collagen-calcium alginate film with therapeutic ultrasound. On application, the collagen-calcium alginate film with therapeutic ultrasound was well accepted by the animals without any adverse reaction. Mean percentage of wound contraction were significantly better in group 4 (p<0.05). Faster epithelialization was also seen in the collagen-calcium alginate film with therapeutic ultrasound treated group as compared to the other groups. Collagen is a biocompatible protein that does not interfere with the body’s normal immunologic response and can be used in non-healing chronic wounds which require a trigger to stimulate the normal healing process. In extensive wounds when there is lack of autologous tissue, biomaterials like collagen-calcium alginate may be beneficial and can be used

    Simulation of High Performance Quantum Well GaN-based LED

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    The performance of quantum well GaN/A1GaN light emitting diode (LED) is reviewed for three different barrier compositions; symmetric barrier composition with low A1 content, asymmetric barrier composition with higher A1 content on p-type cladding layer and lower A1 content on n-type clading layer, and symmetric barrier composition with higher A1 content. The study was conducted using ATLAS/BLAZE & LUMINOUS software developed by Silvaco International Inc. Integrated radiative recombination rate was studied on applied voltages up to 5V. Results showed three phases of LED performance with different applied voltages and these were explained using badgap theory. I-V characteristic for each design agrees with the total additional voltage drop equation for a quantum well structure. The dominant radiative recombination rate regions in LED at low and high supplied voltages are also presented for the best performance LED design

    Decreasing of grid-tied PV power output due to thick haze phenomena in Malaysia

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    Recently, thick haze and poisonous smoke has cloak the surrounding air in Malaysia due to the uncontrollable and unethical burning of nearby country. This devastating episode of open burning started in the year 1997 in Indonesia which deeply affected most of the ASEAN countries especially their neighbour Malaysia and Singapore. The Photovoltaic (PV) technology as an alternative means of energy generation experiences such significant energy decrease based on this condition which is due to the shading of sunlight. The six hours claims of good sunlight has become not more than 2 hours and gets worst when the Air Pollution Index (API) struck 200 levels which is at very unhealthy condition. This study embraces some findings from 1 kWp PV generator field data installed in Malaysia reflecting the daily energy decrease operated during this unhealthy weather condition. It is found that such significant energy decrease with the value of 0.43 W power output per increment of 1 point API. This value shows such concrete proof of additional factors to be considered in PV modelling in line to support PV technology adaptation in the Asean region

    Integrated microRNA and mRNA Expression Profiling Identifies Novel Targets and Networks Associated with Ebstein’s Anomaly

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    Little is known about abundance level changes of circulating microRNAs (miRNAs) and messenger RNAs (mRNA) in patients with Ebstein’s anomaly (EA). Here, we performed an integrated analysis to identify the differentially abundant miRNAs and mRNA targets and to identify the potential therapeutic targets that might be involved in the mechanisms underlying EA. A large panel of human miRNA and mRNA microarrays were conducted to determine the genome-wide expression profiles in the blood of 16 EA patients and 16 age and gender-matched healthy control volunteers (HVs). Differential abundance level of single miRNA and mRNA was validated by RealTime quantitative PCR (RT-qPCR). Enrichment analyses of altered miRNA and mRNA abundance levels were identified using bioinformatics tools. Altered miRNA and mRNA abundance levels were observed between EA patients and HVs. Among the deregulated miRNAs and mRNAs, 76 miRNAs (49 lower abundance and 27 higher abundance, fold-change of ≥2) and 29 mRNAs (25 higher abundance and 4 lower abundance, fold-change of ≥1.5) were identified in EA patients compared to HVs. Bioinformatics analysis identified 37 pairs of putative miRNA-mRNA interactions. The majority of the correlations were detected between the lower abundance level of miRNA and higher abundance level of mRNA, except for let-7b-5p, which showed a higher abundance level and their target gene, SCRN3, showed a lower abundance level. Pathway enrichment analysis of the deregulated mRNAs identified 35 significant pathways that are mostly involved in signal transduction and cellular interaction pathways. Our findings provide new insights into a potential molecular biomarker(s) for the EA that may guide the development of novel targeting therapies

    Control of gray mold disease of tomato caused by Botrytis cinerea using bacterial secondary metabolites

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    Gray mold disease is caused by Botrytis cinerea and it is the most significant and devastating disease affecting tomato cultivation worldwide. This disease was recently reported infecting tomato fruits in Cameroon Highland, Pahang. Biocontrol agents have been proven to be effective towards many phytopathogens. In this study, 43 bacterial isolates were screened against B. cinerea in-vitro. Five isolates with more than 65% inhibition of radial growth (PIRG) were selected for the subsequent experiments. Findings in dual culture assay revealed that BM11 and BC4 were the most effective biocontrol agent, with PIRG of 82.5% and 71.8%, respectively. BM11 and BC4 isolates were identified using the 16S rDNA gene. The identification results found that BM11 and BC4 were Pseudomonas protegens and Brevibacterium casei, respectively. Ten major bioactive compounds were successfully identified by Gas chromatography-mass spectrometry (GC-MS) from the culture filtrate of both biological control agent (BCA) isolates. These bioactive compounds may responsible for antifungal activity. In vivo study revealed that culture filtrate extract manages to suppress disease lesions on the treated tomato fruit from 0.86 -1.03 cM, 30 days after inoculation. Based on overall findings suggested that P. protegens and B. casei were the promising BCA in controlling gray mold disease of tomato fruit

    Modelling and experimental investigation of magnetic flux leakage distribution for hairline crack detection and characterization

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    The Magnetic Flux Leakage (MFL) method is a well-established branch of electromagnetic Non-Destructive Evaluation (NDE) extensively used to assess the physical condition of ferromagnetic structures. The main research objective of this research work presented in this thesis is the detection and characterization of the MFL distribution caused by rectangular surface and far-surface hairline cracks. It looks at the use of the direct current and pulsed current techniques to investigate the presence of hairline cracks in ferromagnetic steel pipelines, by comparing the Finite Element Modelling (FEM) technique with practical experiments. First, the expected response of an MFL probe scanned across the area of a hairline crack was predicted using the 3D FEM numerical simulation technique. The axial magnetization technique is employed and the characteristics of the surface and far-surface leakage field profile

    Fabricated germanium-doped optical fibres for computed tomography dosimetry: Glow curve characteristics

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    Fabricated germanium (Ge)-doped optical fibre glow curve characteristics are investigated with respect to computed tomography (CT) dosimetry. 2.3 mol% and 6 mol% Ge-dopant concentration preforms have been used to produce flat and cylindrical fibres (FF and CF) of various size and diameter. The fibres are irradiated to doses of 20, 30 and 40 mGy for each of the beam qualities RQT 8 (100 kV), RQT 9 (120 kV) and RQT 10 (150 kV). The thermoluminescence (TL) kinematic parameters studied are maximum temperature (Tmax), activation energy (Ea) and peak integral (PI). The glow curve formations are reconstructed from the Windows®–based radiation evaluation and management system (WinREMS), deconvoluted using glow curve deconvolution (CGCD) analysis software. The structures of the glow curves are broad single or double-peaked, occurring at relatively high glow peak temperatures, TL response increases with radiation dose and peak height decreases with increasing energy, showing clear photoelectric dependence. The deconvoluted glow curves for all fibres are seen to consist of five individual glow peaks, P1 to P5, P1 being dominant in all cases other than for 6 mol% Ge-FF for which P3 is dominant due to the formation of a double-peaked glow curve. Tmax increases from P1 to P5 for all fibres, throughout the energy range used. P1 and P3 (6 mol% Ge-FF) have the lowest Ea, while P4 shows the greatest Ea for all fibres. The results indicate that electrons in P1 and P3 (6 mol% Ge-FF) are occupied at low energy traps while for P4, the electrons are trapped at a deeper energy level. The lowest PI value, indicative of the least number of electrons, is shown to be that of the deeper trap P4 for all energies investigated. This study provides support for the use of 6 mol% and 2.3 mol% preform fibres for CT dosimetry, each with similar kinetic parameters

    Impact of the Coronavirus Pandemic (COVID-19) Lockdown on Mental Health and Well-Being in the United Arab Emirates

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    United Arab Emirates (UAE) has taken unprecedented precautionary measures including complete lockdowns against COVID-19 to control its spread and ensure the well-being of individuals. This study investigated the impact of COVID-19 and societal lockdown measures on the mental health of adults in the UAE. A cross-sectional study was conducted using an English and Arabic online questionnaire between May and June 2020. The psychological impact was assessed by the Impact of Event Scale-Revised (IES-R), and the social and family support impact was evaluated using questions from the Perceived Support Scale (PSS). A total of 4,426 participants (3,325 females and 1,101 males) completed the questionnaire. The mean IES-R score was 28.0 ± 14.6, reflecting a mild stressful impact with 27.3% reporting severe psychological impact. Over 36% reported increased stress from work, home and financial matters. Also, 43–63% of the participants felt horrified, apprehensive or helpless due to COVID-19. Females, younger participants, part-timers, and college or University graduates were more likely to have a high IES-R score (p \u3c 0.05). The majority of participants reported receiving increased support from family members, paying more attention to their mental health, and spending more time to rest and relax. The results of this study demonstrate the impact of the COVID-19 pandemic on mental health among the UAE residents and highlight the need to adopt culturally appropriate interventions for the general population and vulnerable groups, such as females and younger adults

    The enhanced naturally occurring radioactivity of negative ion clothing and attendant risk

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    The study investigates commercially available negative ion clothing, and evaluations are made using gamma-ray spectroscopy and Geant4 Monte Carlo simulations. Observed to contain naturally occurring radioactive material (NORM), evaluations are made of the radiological risk arising from the use of these as items of everyday wear, undergarments in particular. Organ doses from these were simulated using the MIRD5 mathematical female phantom, with the incorporation of dose conversion factors (DCFs). At 175 ± 26, 1732 ± 247, and 207 ± 38 Bq, for238U,232Th, and40K respectively, item code S05 was found to possess the greatest activity, while item code S07 was shown to have the least activity, at 2 ± 0.5 and 15 ± 2 Bq, and again for238U and232Th, respectively. Sample code S11 recorded least activity, at 29 ± 5 Bq, for40K. Among the clothing items, sample item code S05 offered the greatest concentrations of Th, U and Zr, with percentage means of 1.23 ± 0.1, 0.045 ± 0.001, and 1.29 ± 0.1, respectively, giving rise to an annual effective dose of 1.57 mSv/y assuming a nominal wearing period of 24 h per day. Accordingly, the annual public dose limit of 1 mSv can be exceeded by their use

    Assessment of Dietary and Lifestyle Responses After COVID-19 Vaccine Availability in Selected Arab Countries

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    The COVID-19 pandemic has been consistently associated with unhealthy lifestyle behaviors and dietary practices. This study aimed to assess the dietary and lifestyle behaviors of adults after COVID-19 vaccine availability and their attitude toward the vaccine in selected Arab countries. A cross-sectional survey-based study was conducted between October 2021 and December 2021 using Google Forms (n = 2259). A multi-component questionnaire was used to collect socio-demographic characteristics, attitudes toward the COVID-19 vaccine, and behavioral, dietary, and lifestyle responses after easing the restriction. Participants were given a score based on the sum of positive dietary and lifestyle changes. The generalized linear models were used to identify the association between positive dietary and lifestyle changes score and sociodemographic characteristics. Weight gain during the pandemic was reported by 39.5% of the participants, 36.1% reported ever getting infected with the COVID-19 virus, and 85% received at least one dose of the vaccine. The key adverse reactions of the COVID-19 vaccine were fatigue, headache, and joint pain, and the main reason for vaccination was protection against infection. Most participants were concerned about the vaccine side effects (45.8%) and inadequate testing (50.7%). After easing of restriction, 54.3% of the participants reduced the frequency of disinfecting objects, and 58.3% joined social events. Most dietary and lifestyle behaviors remained unchanged after vaccine availability but there was an increase in the time spent behind the screen for work (50.1%) and entertainment (42.9%). The results of the multivariate regression analyses revealed that older participants (p = 0.001), those with higher education (p = 0.010), and those working from home (p = 0.040) were more likely to have higher positive dietary and lifestyle changes scores. Although most participants were concerned about vaccine safety, low vaccine hesitancy rates were observed among the study sample. The availability of the COVID-19 vaccines resulted in loosening some of the safety social measures among Arab adults but the negative impact of the pandemic on dietary and lifestyle behaviors remained unaltered
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