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Photosynthetic activity and yield of pegaga (Hydrocotyle bonariensis) grown under natural and artificial light / Indiran Nair Narayanan
No full textLarge leaf pennywort (Hydrocotyle bonariensis) also known as Pegaga in Malaysia, is an herb belonging to the family Araliaceae and commonly used as a culinary leafy vegetable and in preparation of traditional medicines to treat various symptoms of ophthalmic diseases and eczema. The plant is also used as an emetic, diuretic and laxative. With the increasing demand for H. bonariensis by the herbal industry, sourcing plant materials from natural habitats is no longer an economically viable or environmentally sustainable proposition. H. bonariensis is highly sensitive to direct sunlight exposure and water scarcity, which makes successful farming dependent on weather conditions and cultivation practices. Thus, indoor cultivation with optimized lighting system, pertinent water and nutritional supply will be ideal for large-scale production of H. bonariensis. Light-emitting diodes (LEDs) have emerged as one of the promising artificial lighting systems for the plant growth. LED offer technical advantages over traditional lighting sources such as high flexibility for customizing the light spectrum, lower thermal radiation emission, lower energy requirement and high safety performance. In this study, we investigated the influence of LED lighting on growth and photosynthesis of H. bonariensis. Three experimental LED lighting systems, a) Blue and Red (B+R), b) Blue, Red and Green (B+R+G), and c) Blue, Red and Ultraviolet (B+R+U) were compared with natural daylight (NL) for H. bonariensis growth and photosynthesis (20 biological replicates x 3 experimental replicates = 60 plants). Results showed plants grown under the B+R lighting system for a period of 50 days to have higher fresh and dry biomass (fresh biomass; 1180.04 ± 0.085 mg, dry biomass; 190.86 ± 0.002 mg) compared to B+R+G (fresh biomass; 665.84 ± 0.030 mg, dry biomass; 156.56 ± 0.004 mg), B+R+U (fresh biomass; 403.00 ± 0.002 mg, dry biomass; 120.50 ± 0.011 mg) and NL (fresh biomass; 436.00 ± 0.003 mg, dry biomass; 110.84 ± 0.007 mg). Furthermore, photosynthetic pigment content (Chl-a; 17.91 ± 0.14 μg/ml, Chl-b; 8.33 ± 0.19 μg/ml, carotenoids; 3.72 ± 0.38 μg/ml) in plants grown under the B+R lighting system was found to be much higher compared to that of plants grown under the other LED lighting combinations and under NL. The higher photosynthetic pigment and biomass followed by large leaf area (5.61 ± 0.04 cm2), greater plant height (5.87 ± 0.638 cm), and higher number of leaves (17.50 ± 0.761) for plants grown under the B+R LED lighting system indicates that B+R lighting is the most suitable of the systems tested for efficient H. bonariensis farming
Population genetics of Rhizophora apiculata in peninsular malaysia using microsatellite markers / Amelia Azman
No full textRampant illegal logging, overharvesting and deforestation coupled with climate change, pose significant threats to the natural stands of Rhizophora apiculata, or locally known as Bakau Minyak; one of the most economically and ecologically important species of mangroves in Peninsular Malaysia. Despite being a dominant mangrove species, the reduction in the number of R. apiculata in its habitat has resulted in concerns over the long-term survival potential of the species. In Malaysia, genetic information to develop effective guidelines for the conservation and management of mangrove species has been lacking, and hence, further research should be conducted to fill this gap. The present study was therefore designed to generate novel genetic information for R. apiculata, aiming to facilitate the efforts to maintain the genetic diversity of the species in Peninsular Malaysia. A set of novel genic microsatellite markers was generated using an in-house transcriptome dataset of R. apiculata to assess its level of diversity and population differentiation throughout Peninsular Malaysia. A total of 22 identified polymorphic markers were validated and used to genotype 1,120 individuals collected from 39 natural populations of R. apiculata, uncovering its low genetic diversity (He: 0.3523) and high population differentiation (Fst: 0.3150). Low genetic diversity may indicate the occurrence of inbreeding or low levels of gene flow. Based on the microsatellite marker analysis, the populations were separated into two major clusters, corresponding to eastern and western regions of Peninsular Malaysia and coinciding with the Straits of Malacca and the South China Sea. The genetic information generated in this study will enable the formulation of in situ and ex situ conservation guidelines for R. apiculata in Peninsular Malaysia. Additionally, the genic microsatellite markers generated from this study can be used for future research such as population genetic studies of other closely related species as well as for specific applications such as DNA profiling and forensic analysis
Prevalence and determinants of tabacco use among adolescents in Khartoum - Sudan / Mohammed Othman Mohammed Alshaikh
No full textGlobally, 25 million adolescents aged 13-15 years, smoke cigarettes while 13 million
use smokeless tobacco. In 2014, 22.8% of adolescents had ever smoked cigarette in
Sudan while current cigarette smokers were 4.5%; moreover, studies about shisha
smoking and smokeless tobacco were limited in Sudan. The aim of this study is to
estimate the prevalence of tobacco use among adolescents and to describe determinant
factors associated with tobacco use. Descriptive school based cross-sectional study was
conducted, and multistage random sampling was used to recruit participants from
secondary schools in Khartoum State, Sudan. Self-administered questionnaire of Arabic
version of Global Youth Tobacco Survey was used to collect data and multivariate
logistic regression was used to analyse the data. In all, 3387 students from 29 schools
participated in this study during September and October 2016. The outcome, tobacco
use, was defined as ever use if the adolescents had ever used tobacco in the past, while
it was considered as current use if the adolescent used tobacco in the past 30 days.
Among participants, 42.7% were males and 57.3% were females. Public school students
were 51.6% and 48.4% from private ones. The prevalence of current cigarette smoking
was 5.8% and for current shisha use was 3.5%. In smokeless tobacco (toombak) the
prevalence of current use was 2.6%. Determinants of current cigarette smoking in the
study included male students (OR 3.08, 95% CI 1.79-5.29), exposure to second hand
smoke at home (OR 6.44, 95% CI 4.02-10.32), low self-efficacy (OR 12.51, 95% CI
6.69-23.39) , friends smoking (OR 4.50, 95% CI 2.58-7.84) and not trying to buy
cigarette (protective factor) (OR 0.30, 95% CI 0.14-0.63). While for current shisha use
determinants were studying in public school (OR 2.20, 95% CI 1.20-3.70), exposure to
second hand smoke outdoors (OR 2.30, 95% CI 1.20-4.13), anti-tobacco message (OR
2.60, 95% CI 1.40-4.84), low self-efficacy (OR 11.40, 95% CI 5.90-22.00) and friends
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using shisha (OR 6.59, 95% CI 3.40-12.74). For current smokeless tobacco use
determinants were male student (OR 54.80, 95% CI 12.00-248.90), exposure to second
hand smoke at home ( OR 4.72, 95% CI 2.24-9.97) and indoors (OR 12.47, 95% CI
3.99-38.98), low self-efficacy ( OR 114.00, 95% CI 36.30-357.60), friends using
smokeless tobacco (OR 3.38, 95% CI 1.52-7.49), living in Khartoum city (protective
factor) (OR 0.22, 95% CI 0.09-0.54), pro-advertising (protective factor) (OR 0.36, 95%
CI 0.16-0.81) and not trying to buy smokeless tobacco (protective factor)(OR 0.08, 95%
CI 0.01-0.42). The Assessment of the magnitude of tobacco use among adolescents
represents a useful tool to compare the trend over time. Moreover, the determinants
factors will help to identify adolescents at high risk of tobacco use. These results can be
utilized to help develop an effective peer based prevention programs in schools since
the peers have the greatest effect on adolescents.
Keywords: Adolescent, Tobacco, Cigarette, Shisha, Smokeless tobacc
Development and evaluation of hearing conservation program among vector control workers / Rama Krishna Supramanian
No full textNoise-induced hearing loss (NIHL) is one of the highest recorded occupational disease
despite being preventable. In 2018, occupational noise-induced hearing loss was the
highest reported occupational disease experienced by workers in Malaysia accounting for
87.7% of all occupational diseases. The aim of this study is to develop, implement and
evaluate the effectiveness of a Hearing Conservation Program (HCP) in preventing noise�induced hearing loss among vector control workers. This study is divided into two phases:
development of HCP (phase 1) and implementation and evaluation of HCP (phase 2). The
development phase (phase 1) included a review, interview with key stakeholders and
reviewing local and international guidelines. In phase 2, the HCP was implemented and
evaluated using a cluster-randomized controlled trial design. A total of 183 vector control
workers from nine district health offices in the state of Perak, Malaysia were randomized
to intervention or control group. The multifactorial intervention included noise exposure
monitoring, noise control, proper use of hearing protection devices, training and
education session, audiometric testing and hazard communication. Three strategies for
NIHL prevention were identified from the review: championed by leaders, one-off
training and multifactorial intervention (combination of multiple strategies). The mean
age of the participants were 37.7 and 36.6 years old in the intervention and control group
respectively. The majority of participants in both groups were males, Malay ethnicity,
and general workers with a highest education level of secondary education. The baseline
mean hearing threshold observed for the grouped frequencies (2, 3 and 4 kHz) was higher
among the intervention group (24.9 dB) compared to the control group (16.1 dB) for the
left ear. Similar trends were observed for the right ear with 23.6 dB (intervention) and
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14.8 dB (control). As for the grouped frequencies (0.5, 1, 2 and 3 kHz) the intervention
group also showed higher mean hearing threshold compared to the control group with
20.8 dB (left ear) and 22.1 dB (right ear). The baseline mean score for knowledge, attitude
and practice score towards NIHL was 77.8, 75.1 and 62.9 for intervention group while
the control group participants averaged 73.5, 70.7 and 71.2. After 3 months, the
intervention group showed a greater reduction (0.06 dB reduction) in mean hearing
threshold in the left ear for the grouped frequencies (2, 3 and 4 kHz). As for the grouped
frequencies (0.5, 1, 2 and 3 kHz) both intervention and control group showed a reduction
in mean hearing threshold of 1.4 dB and 2.6 dB respectively for the left ear. There was
also a greater improvement in the mean score for knowledge, attitude and practice
towards noise-induced hearing loss (NIHL) in the intervention group as compared to the
control group but were not statistically significant. The HCP has shown to be effective in
preserving hearing of vector control workers as well as improving their knowledge,
attitude and practice towards NIHL.
Trial registration: TCTR20190109002
Funding: University of Malaya Grand Challenge (PEACE) (GC001A-14HTM)
Keywords: noise-induced hearing loss, vector control worker, occupational exposur
Adoption of e-Wallet among University of Malaya students / Tan Jia Enn
No full textMalaysia is towards a cashless nation and factors that delaying the process of cashless
society are still unclear. The objective of this paper is to examine the adoption of e-wallet
among University of Malaya (UM) students. The purpose is examined by key
determinants which include social influence, perceived ease of use, perceived
usefulness, perceived security and trust among university students. Data is collected by
a self-administered survey questionnaire from University of Malaya (UM) students.
Software IBM SPSS is adopted to analyse the data collected from survey questionnaires.
The findings in this study shows that social influence and perceived usefulness are a
significant determinant towards adoption of e-wallet. While, perceived ease of use,
perceived security and trust are not an important determinant on adoption of e-wallet
Dental therapists' professional role and possible futures within the Malaysian dental workforce / Noor Azhani Zakaria
No full textIntroduction: The Malaysian Dental Act 2018 has recently superseded the Dental Act
1971. Under this Act, dental therapists are required to register under the Therapist
Division, are allowed to work at the private practice, and treat a person up to the age of
18 years old under direct supervision of dentist. It is important to assess the perceptions
among essential stakeholders with regards these changes and how it affects the future
dental therapists’ workforce. Objectives: To explore the dental therapist future
workforce dynamics across sectors (public-private) in Malaysia. Materials and
methods: In Phase 1, three parallel quantitative surveys were conducted using validated
self-administered questionnaires. Descriptive, univariate and multivariate analyses were
undertaken using SPSS Version 20. The findings in Phase 1 were integrated with
relevant data to model the supply, need and demand in a System Dynamic (SD) tool
using Vensim Version 7.3.5 from a baseline scenario in 2015 to the projected year of
2030. Four exploratory scenarios were then modelled to explore the implications of
working delegation and privatisation within the Malaysian dental workforce. Results:
Majority (>90%) of dental therapists had high job motivation with total mean score of
5.9 ± 0.51. Almost one-quarter felt dissatisfied with their pay rate (24.2%) and
promotion opportunity (20.5%). 87.6% expected to stay longer in the dental
professional and 8.3% of them had the intention to leave the government sector for
private sector. Those who foresaw working in the private sector within the next five
years were 4.14 times more likely to have the intention to leave than those who
preferred to stay in the public. About 71% of parents had a high level of acceptance of
dental therapist providing care to their children in the private settings. Younger parents
(OR=1.71, 95% CI=1.26,2.52), those who lived in the urban (3.43; OR=1.71, 95%
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CI=1.23,2.36) and of Bumiputera origin (OR=1.92, 95% CI=1.08,3.43) were the
predictors of the high acceptance level. Private dentists’ attitude towards the
employment of dental therapists at the private settings was low (15.5%) and it is
significantly related to their ownership type (p=0.01). The main perceived barriers were
cost (69.5%) and perceived lack of knowledge/skills among dental therapists (52%).
Finally, SD modelling simulation for baseline scenario shows a potential for oversupply
of public dental therapists and private dentists by year 2025 while a potential of
undersupply for public dentists throughout the simulation period. The multiple scenarios
could range from a shortfall of total public practitioners and surplus of private
practitioners by the year 2030.
Conclusion: This study highlights the perceptions on the Therapist Division stipulated
in the Dental Act 2018 among different stakeholders that can be used as a reference
source to the oral health policymakers in managing human resources. Findings
portrayed that by increasing dental therapists’ administrative and promotion roles within
the private settings has the potential to absorb the potential oversupply at the private
sectors in the future and this scenario shows the optimum utilization of the entire dental
workforce in Malaysia.
Keyword: Dental therapist, private practice, human resource planning, policy
changes, computer simulatio
Synthesis, cytotoxicity and apoptosis studies on nickel and zinc derivatives of testosterone-N4-substituted-thiosemicarbazones / Heng Mok Piew
No full textThe side effects of cisplatin such as toxicities are mainly due to the lack of selectivity of this chemotherapeutic agent. In order to increase the selectivity of an anticancer agent, hormone molecule that targets a specific receptor may be utilized. This research aimed to prepare cytotoxic Schiff base compounds (and their nickel and zinc complexes) with testosterone and derivatives of thiosemicarbazide, which are potentially selective towards cancerous cells. Three Schiff base ligands (TM, TF, and TP) were made from the conjugation of testosterone with three derivatives of thiosemicarbazide (N4= methyl, fluorophenyl, and ethylphenyl) and their respective nickel (NM, NF, and NP) and zinc complexes (ZM, ZF, and ZP). A zinc complex ZE (N4= ethyl) was included as well. Characterizations of these compounds were done by means of FTIR, CHN elemental analyses, 1H-NMR and 13C-NMR, and X-ray crystallography. Mononuclear complexes of NM and NF adopt a distorted square planar geometry, with two molecules of Schiff base ligand coordinated to the nickel ion via two imine nitrogens and two tautomeric thiol sulfurs. The cytotoxicity of these compounds against several human cancerous cell lines (prostate cancer cell line PC-3 and LNCaP, breast cancer cell line MCF7, colorectal carcinoma cell line HCT 116) and their general toxicity against two human normal cell lines (normal prostate RWPE-1 and normal colon CCD-18Co) were investigated, with cisplatin as positive reference standard. Eight out of the nine synthesized compounds were cytotoxic towards the HCT 116 colorectal carcinoma cell line tested, while only two of them were toxic against the CCD-18Co normal colon cell line tested, reflecting high selectivity index of these compounds against the colorectal carcinoma cell line. Morphological changes induced by these compounds were observed and photographed. Ability of the cytotoxic compounds to induce apoptosis was proven via flow cytometry and this study was then focused on colorectal carcinoma cell line due to the high selectivity index. Five of the cytotoxic compounds (TM, NM, TF, TP, and NP) were able to depolarize the mitochondrial membrane potential, thereby suggesting their capability to induce intrinsic apoptotic pathways. All the cytotoxic compounds successfully arrested cell cycle of HCT 116 at G0/G1 phase. Furthermore, all the nine compounds were proven to bind to the DNA surface and they might be DNA minor groove binders. However, the general toxicity of TF against all the tested cell lines (IC50 values range from 12.03 to 29.37 μM) might be due to its outstanding affinity towards DNA (Kb = 2.9 × 107 M-1), while high selectivity of ZP (SI>3.22) might be due to its weak DNA binding strength (Kb = 3.7 × 105 M-1). The three compounds (TM, NM, and ZP) were able to suppress enzymatic reaction of topoisomerase I, thereby suggesting the cytotoxicity of these compounds against the colorectal carcinoma cell was due to their topo I inhibitory properties. Such inhibition might in turn, block the cell from entering S phase of cell cycle, and the cells might then be subjected to programmed cell death
New alkaloids from selected Malaysian alstonia and Lycopodium species and their biological activity / Joanne Yeap Soon Yee
No full textTwo Malaysian plants, Alstonia penangiana Sidiyasa (family: Apocynaceae) and Lycopodium platyrhizoma J.H.Wilce (family: Lycopodiaceae), were investigated for their alkaloidal composition. This project represents the first reported phytochemical study on these two plant species. A total of 94 alkaloids (1−94) were isolated and characterized from the leaf and stem-bark extracts of Alstonia penangiana, a plant endemic to Penang Island, Malaysia. Of these, 32 are new alkaloids. The leaf extract of A. penangiana yielded a total of 15 new alkaloids, including a pair of type-A and type-B macroline isomers (1, 2), four macroline oxindoles (20–23), three talpinine-type oxindoles (41–43), two ajmaline alkaloids (57–58), as well as four macroline-akuammiline bisindoles (76–79). The stem-bark extract of A. penangiana gave a total of 19 new alkaloids. These include seven sarpagine alkaloids (32–38), an akuammiline alkaloid 39, a C14 methylene-bridged indolizidine derivative (40), seven macroline-sarpagine bisindoles (80–86), and a macroline-pleiocarpamine bisindole 88. Evaluation of the in vitro growth inhibitory activity of the new alkaloids against a panel of human cancer cell lines, including KB/S, KB/VJ300(−), KB/VJ300(+), PC-3, LNCaP, MCF7, MDA-MB-231, HT-29, and HCT 116 cancer cells showed strong cytotoxicity for the bisindole alkaloids (76–77, IC50 0.3−8.3 μM; 80–86, IC50 0.02−9.7 μM). A total of 19 alkaloids (95−113) were isolated and characterized from the whole plant of Lycopodium platyrhizoma. Of these, three are new alkaloids, including two lycodine alkaloids (95–96) and one fawcettimine alkaloid (110). Lycoplatyrine A (95) is an uncommon lycodine alkaloid having C-2 substituted with a C5N (piperidine) moiety. The alkaloid compositions of the two plants are summarized in Table 2.1 and Table 2.61
Challenges of international development projects in Yemen: Perspective of public work project / Hassan Mohammed Mohammed Lashuel
Get PDFInternational development projects are public projects that are created to support the economy and people’s life needs, mostly these types of projects target developing countries. These types of projects face challenges more than other projects due to many reasons. Accordingly, this research aims to explore the challenges that face international development projects in Yemen and conducted by the Public Work Project and highlight the most significant issues that face ID project as well to overcome these challenges. This research adopted the qualitative method by conducting ten semi-structured interviews with the PWP team and others stakeholders. The interview technique was selected to collect the data from the respondents from different backgrounds. Consequently, the data were analyzed using thematic analysis, which lead to creating themes for every group of respondents. Many challenges based on the PWP team were found as well as the other stakeholders. Based on the results, there are many challenges related to project management, personal interests and favoritism, delay, economy and security in the country, as well the issues related to contractors. For the highlighted challenges, recommendations from the respondents were developed, the long period of negotiation for the projects, should not be part of the project life cycle, additionally, the community should conscious of the benefits of development projects as well the other stakeholders. This research contributes significantly to improving the practice of the field of international development projects in Yemen as well as the other developing countries
Short-term electricity price forecasting in deregulated electricity market based on enhanced artificial intelligence techniques / Alireza Pourdaryaei
No full textElectricity price forecasting is considered as one of prime factors for operation, planning and scheduling of price-setter market participants. However, possessing time variant, non-linear and non-stationary behaviors make the electricity price a complex signal. The main challenge in this area is providing highly accurate and efficient day-ahead price forecasting. A suitable feature selection technique, which is able to model the interacting features and nonlinearities of the forecast processes, is still required although researches have been performed for day-ahead forecasting. In this research, a hybrid electricity price forecasting methodology is proposed using two-stage feature selection method and optimization using adaptive neuro-fuzzy inference system (ANFIS) technique as a forecasting engine. An important contribution of the proposed method is modeling of interaction in addition to relevancy and redundancy based on information-theoretic criteria for the feature selection. A multi-objective feature technique is developed in this study to extract the most influential subsets of input variables with the maximum relevancy and minimum redundancy. The proposed feature selection technique comprises of Multi-objective Binary-valued Backtracking Search Algorithm (MOBBSA). It is used to search within a number of input variables combinations and to select the feature subsets, which minimizes simultaneously vice-versa the estimation error and the feature numbers. In the developed method of multi-objective feature determination, MOBBSA is used to search within different combinations of input variables and to select the non-dominated feature subsets. ANFIS is applied as an evaluation metric to determine the performance of every feature subset. The other foremost contribution of the work is proposing a hybrid electricity price forecasting technique to provide more accurate forecasts. This merit is provided by balancing the exploitation of solution structure and exploration of its appropriate weighting factors through the use of Backtracking Search Algorithm (BSA) as an efficient optimization algorithm in learning process of ANFIS approach. Real-world electricity demand and price dataset from Ontario and Australia power markets, which are reported as among the most volatile market worldwide, have been used to validate the performance of the proposed approach. Finally, the obtained results corroborate the premise of the proposed method through the enhanced accuracy compared to the existing artificial intelligence-based models