13474 research outputs found
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Population genetics and anticoagulant resistance of Rattus tiomanicus in oil palm plantation inferred from VKORC1 gene mutations / Mohamad Harris Nasir
No full textRat of the Rattus species is the main group identified as pests in oil palm plantation in Malaysia. The constant use of anticoagulant rodenticides (ARs) for rat control in oil palm plantations exert selective pressure on Vitamin K epOxide Reductase Complex subunit 1 (VKORC1), potentially resulting in rodenticide resistance. The aims of this study were to determine Rattus species diversity by using genetic tools and to characterize the dominant species population structure. In addition, the resistance region of VKORC1 gene in the population of Rattus species and assess the impact to the rodenticides efficacy rate were investigated. Rats from five oil palm plantations in Peninsular Malaysia were trapped from 2018-2019 and morphologically identified. COI sequences extracted from the rat liver tissue were used for molecular identification based on DNA barcoding and population structure analysis. The VKORC1 gene was screened for mutations using MEGA X software, and the mutated residue’s structure was visualized using the I-TASSER platform. Molecular docking using Chimera software were also used to predict the favoured interaction between the mutated protein structure and the ARs active compound to support a possible AR resistance. A total of 341 COI sequences of rats were used for the species identification. Based on DNA barcoding analysis and phylogenetic analysis, R. tiomanicus was the most abundance in our study sites with highest diversity index (H’= 1.31) compared with other species; R. argentiventer, R. rattus diardi, R. exulans and R. tanezumi. The most abundance, R. tiomanicus has been chosen for the population structure study and VKORC1 screening. In this study, a pattern of isolation by distance was detected in R. tiomanicus populations, suggesting an unlikely event of inbreeding and migration with no recent event of population pattern expansion and low gene flow between populations (FST= 0.045, p>0.001). Thus, population migration is not a risk factor in eradication effort. Screening on the R. tiomanicus VKORC1 gene resulted in identification of four mutated foci on residue Gly64Ala, Gly64Val, Leu65Pro and Glu67Ala in Exon 2 that led to nonsynonymous mutations. The outcome of the protein-ligand interaction with the active compound of ARs shows a promising lead to the development of resistance towards Brodifacoum, Flocoumafen, and Bromadiolone. This result is important to determine which type of ARs are safe to use in the oil palm plantation to control the rats. Analysis between resistant (R-) and susceptible (S-) populations of R. tiomanicus resulted in a negative result of Tajima’s D and significant FST, implying a recent population expansion that was caused by balancing selection due to rodenticide use in the oil palm plantation. The population is at a high risk if a large number of resistant individuals migrate from outside the treated region, the frequency of resistance may develop more rapidly than expected by rodenticide usage. Thus, control programs should be coordinated between neighbouring plantations within each population for successful and more effective eradication campaigns, as well as to limit the frequency of rodenticide resistance in oil palm plantations
Synthesis and characterization of N hydroxymethylacrylamide based self-healable hydrogels for supercapacitor / Silvaraj David
No full textHydrogels are garnering increasing interest in scientific and technological development as a result of their ability to be able to hold a large volume of water. This characteristic is possible due to the presence of a hydrophilic polymer strain, which results in the material's widespread use. Due to their soft physical properties, they are an attractive material for use as electrolytes in supercapacitors. However, when hydrogels are used as the electrolyte in supercapacitors, critical issues such as electrochemical performance, stability, and a small potential window are raised in comparison to supercapacitors constructed using organic electrolytes. Recent advancements in the development of a unique water-in-salt hydrogel electrolyte supercapacitor with a broad potential window has sparked attention. As a result, the present work utilised the free radical method to synthesize poly (N-hydroxymethylacrylamide) (PNHMA) hydrogel and lithium salt-containing hydrogel electrolytes. The free radical initiator was ammonium persulfate, while the crosslinking agent was sodium montmorillonite (clay). Lithium trifluoromethanesulfonate (LiTF) salt was introduced as an ion source due to the salt's ionization producing free-moving ions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), and field emission scanning electron microscopy (FESEM) were used to analyse the produced hydrogel electrolytes. The ionic conductivity of the produced hydrogel electrolytes was determined using electrochemical impedance spectroscopy (EIS). The hydrogel electrolyte containing 30 wt.% LiTF (NHMA3) demonstrated the maximum ionic conductivity of 6.6 x 10-3 S/cm and the lowest activation energy (Ea) of 0.085 eV. The hydrogel electrolytes were embedded in an electric double layer capacitor (EDLC) using an activated carbon electrode and then characterized using cyclic voltammetry (CV) and galvanostatic charge discharge (GCD). These two approaches demonstrated that the hydrogel based supercapacitor with the setup of AC/NHMA3/AC exhibited a maximum specific capacitance of 165.19 F/g at 5 mV/s and 287.96 F/g at 200 mA/g, as well as a specific energy of 39.63 W h/kg and a specific power of 199.16 W/kg. Additionally, after 5000 cycles at a current density of 5 A/g, the supercapacitor retained 98.5 percent capacitance. As a result, it can be concluded that hydrogel electrolytes created in this study have tremendous potential for smart, lightweight, and flexible electronic devices
The prevalence and psychosocial correlates of ketum use among individuals on methadone maintenance therapy programme in Hospital Taiping / Choo, Ling Ling
No full textBackground: Ketum use is significantly prevalent amongst individuals in northern states
of Peninsular Malaysia. This study aims to investigate the prevalence and psychosocial
correlates of Ketum use in individuals who are in the Methadone Maintenance Therapy
(MMT) Programme in Hospital Taiping.
Methods: This is a cross-sectional study conducted in the methadone clinic Hospital
Taiping. Non-probability convenience sampling was used in this study. The study
instruments used were Subjective Opiate Withdrawal Scale (SOWS), Alcohol, Smoking
and Substance Involvement Screening Test (ASSIST) questionnaire, and Kratom
Dependence Scale (KDS).
Results: A total of 215 subjects were recruited in this study. The prevalence of ketum
users was 49.3% (n=106). The factors which were significantly associated with ketum
use (p < 0.05) in MMT programme were ethnicity, duration in MMT programme, other
illicit drugs use, and SOWS.
Conclusion: Ketum use is prevalent amongst those in MMT programme in this study.
The high prevalence of ketum use is of concern and further interventions should be
carried out to address thi
The effect of temperature on drawability of circular and square sheet metal drawing / Muhammad Basril Muhammad Asri
No full textSheet metal drawing is a well-known process used in today's industries, and the most
significant challenge encountered throughout this process is product quality. In sheet
metal drawing, product quality is vital and based on current research trends, varying the
process temperature improves the quality.
This study focuses on the influence of tooling temperature on the drawability of sheet
metal drawn circular and square cups with various blank sizes. Following that, an
evaluation of the impact of different process parameters on the warm sheet metal drawing
was carried out. Consequently, the drawability of circular and square cups will be
analysed by comparing experimental and finite element analysis (FEA) data.
The Taguchi method L9 (34
) array experiment design was used to plan the process
parameters and the experimental design in this study. The experimental procedures were
prepared with the experimental apparatus's consideration. The experimental setup
apparatus for circular and square cups, which includes a die set, heater, thermocouple,
hydraulic pump and cylinder, is then put through a series of tests. Firstly, circular cups of
aluminium 6065 (AL6065), mild steel (MS), and stainless steel 304 (SS304) were drawn
from the blank with diameters of 60 mm, 65 mm, and 70 mm. Next, the same material
was drawn for square cups with a blank diameter of 45 mm, 50 mm, and 55 mm. Both
cup shape is tested at room temperature, then at temperatures of 100°C, 150°C, and
200°C.
The response factors consist of limiting drawing ratio (LDR), average cup height and
thickness distribution were collected from room and warm temperatures. First, these
outputs were analysed using the analysis of variance (ANOVA) to determine their effect
on warm sheet metal drawing. Then, the sheet metal drawing process is simulated using
ABAQUS/CAE software to predict the drawn cup thickness distribution. Eventually, the simulated data will be compared with the experiment for verification. From the ANOVA analysis, the blank material had the most significant impact on the
drawability of warm sheet metal drawn circular cups, followed by the blank size, heating
technique, and heating temperature. The optimal parameter was 65 mm of the AL6065
blank with a heating temperature of 150°C applied to the punch. On the other hand, the
drawability of warm sheet metal drawn square cups was substantially impacted by the
blank size, followed by the material, heating technique, and heating temperature. The
optimal parameter was 45 mm of the AL6065 blank with a heating temperature of 150°C
applied to the punch
Infrastructure policy making at the local government of the West Bank, Palestine: Case study of the water sector / Feras Ali Hasan Qawasmeh
No full textLocal governments interact with inhabitants more dynamically than the central government to respond to their problems and needs, which usually are related to basic infrastructure services. In the West Bank context, there are various issues of the infrastructure services. These issues at different degrees of challenges are generally related to limited access of services, poor quality, low satisfaction level, limited Palestinian control over resources and others. However, previous literature has focused more on identifying these issues at the operational level. Substantially, few studies are found to look at the service delivery process from the policy perspective. The main goal of this study is to investigate the infrastructure policy making at the local government of West Bank, considering the water service/sector as a case study. This main goal is then supported by three research objectives. The first objective is to analyse the effects of politico-administrative and structure/institutional framework on the water policy making process, while the second objective is to investigate the challenges/issues in water policy making process. Further, the last objective is to identify the impact of the current policy formulation process of water service on the services delivery. A qualitative research approach was adopted to collect data to achieve the objectives of the study. The research utilises mainly primary data, supported by secondary data when needed. The interview was employed to gather the primary data, while scholarly works, government documents, and archival records are used to gather the secondary data. The results show that the water sector mainly suffers from legislative, institutional and operational problems. Subsequently, solutions were drafted to overcome them. However, the main issue of water service policy making is the gap between the water service formulation process and implementation process, which makes the current water service delivery process inconsistent with the water policies. The main reason behind this gap is found to be the non-issuance of related regulative policies by the Palestinian Cabinet of Ministries. However, the results also show that there are five interrelated factors which led to create this gap. These factors are the Israeli Occupation, foreign funds, legal/institutional framework including overlapping powers, preceding laws, deactivation of the Palestinian Parliament and local government structure, administrative issues including weak leadership integration, internal politics and financial spending pattern of service providers, and lastly public opinion. Theoretically, the Advocacy Coalition Framework (ACF) was found to be appropriate in explaining the water formulation process with some modifications made to suit the Palestinian governance context. Nevertheless, it neither explained the gap in the policy making nor the current service delivery process. Hence, the study introduced a model termed as “Fire-fighting Approach” to explain the current water service delivery and how decisions are made. Arguably, decisions of water service delivery are determined by the urgent needs of people and the availability of financial resources and technical capabilities. These decisions are not necessarily consistent with the water policies. Lastly, the study recommends policy/decision makers to enhance the accountability mechanism, outsource tasks that they have little capabilities with, boost the role of think tanks and issue needed regulative policies while gradually translating them into actions
Studies on effect of bicarbonate ions and pH on physiology and moisture content of Gracilaria changii / Nur Faraheen Mohd Fadil
No full textOcean acidification is the after-effect changes in seawater chemistry caused by rising atmospheric CO2 levels and the resulting repercussions on marine life. In less than a decade, this phenomenon has become one of the most severe and crucial concerns confronting the ocean research community and marine resource managers alike. Seaweed plays a vital role in the coastal carbon cycle and contributes remarkably to sea-farming activities. This research aims to determine the effect of different dissolved inorganic carbon (DIC) concentrations on seaweed and their specific growth rates (SGR). Also, this study investigated the potential of red seaweed, G. changii, as a carbon sequester. Based on our preliminary findings, G. changii can survive in acidic conditions at least at pH 6 but showed better growth performance at pH 8. In terms of SGR, all seaweeds have shown various adaptation responses every week in all bicarbonate concentrations, which showed that increased CO2 concentration might enhance, inhibit, or not affect growth
Development and validation of heptaplex polymerase chain reaction assay for the discriminatory detection of selected meats in food products / Syed Muhammad Kamal Uddin
No full textFood fraud is one of the most prevalent problems of the present day. It is important for consumers to ascertain the authenticity of the declared ingredients in food products. Beef, buffalo, goat, sheep, chicken, duck, and pork are the heavily consumed meats having enormous importance from nutritional, economic, and cultural/religious viewpoints and are often found to be mutually adulterated in raw and processed states. Available DNA-based approaches for species authentication are commonly based on long DNA markers that can be damaged during food processing, rendering the methods less reliable. The objective of the project is to develop a heptaplex Polymerase chain reaction (PCR) assay targeting short length amplicons for the detection and differentiation of bovine, buffalo, goat, sheep, chickens, ducks, and porcine materials in food chain simultaneously. Both conventional and real-time PCR systems were developed, and authentic target detection was ensured through sequencing and Restriction Fragment Length Polymorphism (RFLP) analysis. Mitochondrial cytochrome b (cytb) and NADH dehydrogenase subunit 5 (ND5) genes were targeted and seven different targets (73-263 bp length) each for pig (73 bp), cow (106 bp), buffalo (138 bp), chicken (161 bp), duck (203 bp), goat (236 bp) and sheep (263 bp) were amplified from raw as well as boiled, microwaved, and autoclaved meats under pure and admixed states. The specificity of the PCR assays was tested against seven target species and other related 19 non-targets. Specific PCR products were obtained only from the targeted cow, buffalo, goat, sheep, chicken, duck, and pig without any cross-species amplification. The use of universal eukaryotic primers eliminated any chance of false-negative detection. The assay was sensitive enough to detect 0.01-0.005 ng of DNA from raw meat and 0.5% (w/w) adulterated meat under mixed and commercial matrices. The amplified PCR products from the targets showed more than 98% (98.5-100%) sequence similarity with specific target sequences in GenBank. The PCR products were digested by the restriction enzymes namely FatI, BfaI and HPY188I that confirmed the authentic molecular fingerprints from the seven target species. The novel methods were applied to screen various commercially processed foods, namely meatballs, frankfurters, burgers and meat curries. A market survey revealed that 100% of beef meatballs were adulterated with buffalo along with total beef replacement in 20% of cases. Beef frankfurters and burgers were adulterated with buffalo in 84% cases. Beef curry samples contained 90% buffalo contamination. In contrast, porcine products were found to be 100% authentic and no porcine was detected in the halal branded foods. Finally, the developed TaqMan probe-based multiplex real-time PCR (mqPCR) systems successfully detected 0.006 ng DNA in raw state and 1% adulterated meat in mixed and commercial matrices. Screening of commercial products by mqPCR assays showed that 85% of beef burgers and 100% of beef frankfurters, meatballs and cocktails were adulterated with buffalo. Lamb products were also buffalo contaminated. Pork products contained chicken (50%). Given some advantageous features, including stringent specificity, exceptional stability and sensitivity, the developed approach could discriminatorily detect and quantify the target species even in severely processed specimens
Neural network with agnostic meta-learning model for face-aging recognition / Rasha Ragheb Attaallah
No full textFace recognition is one of the most popular and accessible verification techniques. It is also accepted by users as it is non-invasive. Nevertheless, the aging process may change the face shape and texture. Therefore, aging is considered one factor that affects the accuracy of face recognition applications. Existing techniques and methods for face aging recognition are degraded in performance due to many factors, such as the uncontrolled nature of aging processes of the human face. Thus, there is a need to further investigate face aging recognition techniques, particularly the one which can be used to compare two images of faces for the same person at a different age. This study aims to design and model a framework to recognize face aging based on artificial neural networks and Model-agnostic meta-learning (MAML), using parameters obtained from identical tasks with certain updates on these parameters. The thesis presents the main parts of the research methodology. The literature review and problem extraction are reviewed in phase 1. Phase 2 explains the research objectives. Phase 3 shows the proposed model design and implementation. Finally, phase 4 shows the analysis of the results based on the proposed framework.
The methodology starts with phase one, which includes the literature review and problem extraction. During this phase, a review of existing research was done, followed by the extraction of all face recognition challenges. This helps in defining the problem statement. The second phase includes the determination of the research objectives and explaining them. The third phase proposes the framework, shows the design and the implementation. The fourth phase explains the results, demonstrates the analyses and the evalutes the data
Socioeconomic conditions and subjective well being of the displaced community in Putrajaya, Malaysia / Suresh Raja Manickam
No full textIssues of socioeconomic conditions and subjective well-being (SWB) of development-induced displacement due to out-migration of plantation workers have hardly been discussed in the context of Malaysian rubber plantations. Indeed, the available evidence on this community is reflected only in anecdotal evidence and a piecemeal approach in the media public. This reflects the lack of understanding of the true socioeconomic conditions of the displaced community for any policy intervention by policy makers. This study therefore seeks to examine the socioeconomic conditions and SWB, particularly life satisfaction, as well as the drivers of SWB in the Indian displaced community in Malaysia. In addition to assessing the socioeconomic conditions and SWB of the study group, the study also examines the intergenerational mobility of the community. The study uses a mixed-methods approach, employing both qualitative and quantitative methods, using a combination of questionnaire survey and interviews. The study uses the displaced community in Taman Permata, which was displaced from three main settlements, as a case study for the research. The main findings of the study indicate that the socioeconomic conditions of the displaced community have not improved significantly. For example, the income level of the displaced community remains low, with an average income of RM 722 and a median income of RM 625, which is below the national level. Experience also does not contribute to income differences in the displaced community, suggesting that the community is trapped in an occupational class where experience does not matter. There is also a large income gap between men and women. Almost 96% of households also have no other sources of income, with 75% of households unable to survive without income for more than 1 month. Similarly, lack of financial stability is one of the critical factors for the community. In terms of intergenerational iv
mobility, there has not been much progress in the community as a whole, especially in terms of educational mobility which limits income opportunities. It is also noted that the community has a high school dropout rate - almost 28%. The main reasons for dropping out of school are financial and family problems, which account for 53%. There is also a lack of social support and network, which limits the possibility of seeking additional help. More importantly, safety in their neighbourhood was mentioned as one of the main problems - gangsterism and robbery are the biggest safety issues. Although the socio-economic factors did not show much progress, selected segments of the community shows some very positive attitudes towards their subjective well-being. Financial instability, family relationships, the physical environment and relationships with neighbours were found to be the most important factors for SWB. This suggests that the social network was key to improving the SWB of the displaced community as they were displaced from the settlements. Income, gender, household size and education do not seem to explain SWB. The study concludes with policy implications and future research directions. It is crucial to improve access to education, income opportunities and the overall living environment to improve the socio-economic conditions and subjective well-being of the community
Quality factor improvement of on-chip meander line resistor in high frequency operation / Wong Goon Weng
No full textHigh-performance radio frequency integrated circuit (RFIC) applications are required in the rapidly growing microwave communication technology. Realising high-performance quality factor passive components at microwave frequencies have become challenging. The parasitic effect on the performance of the passive component draws the attention of manufacturers and researchers to the limiting RFIC application. On-chip resistors are embedded passive components that are widely used in the design of RFIC microelectronic circuits such as voltage-controlled oscillators, filters, and low noise amplifiers in electronic system-on-chip (SoC). The challenges in designing on-chip resistors included small package size, high-level integrity, reducing parasitic coupling effect, producing high resistivity and frequency stability with an acceptable low-quality factor operating at a high frequency. This thesis demonstrates an on-chip n-well meander line resistor configuration with higher sheet resistance, lower silicon area consumption and method design for improvement of Q factor over conventional straight lines on-chip resistor configuration. The on-chip n-well meander line resistors are designed and optimised for reducing the parasitic coupling effect with a low Q factor at less than 1.0 oscillate beyond 1 GHz frequency. Using a Sonnet 3D full-wave electromagnetic simulator, this thesis provides simulation analysis and validation for the proposed design on-chip meander line n-well resistors configuration. Three methods for improving on-chip meander line n-well resistor configuration with improved Q-factor performance were presented. The first DOE Factorial design method and the theoretical performance geometrical parameters of on-chip meander line n-well resistors were investigated. The simulation results showed that distance spacing increased and width widened with a decrease in parasitic capacitance coupling. Using the factorial design experiments DOE techniques, the optimised geometrical parameters configuration were achieved with a low-quality factor in 0.0713 at 1 GHz frequency, which improved by 94.02% compared to the conventional structure. The second additive method showed that the shielding ground conductor inserted into between segment n-well meander line reduced the parasitic capacitance coupling effect. Using a T-shaped shielding ground conductor with