UMT Journal Universiti Malaysia Terengganu
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FUNGAL SPECIES ASSOCIATED WITH BLACK SPOT DISEASE IN ROSE
Black spot disease is a significant worldwide disease on the rose plant. Due to this infection, the leaves become yellow and eventually fall off. The occurrence of this disease has become a major problem, especially in landscape purpose. Therefore, this research was conducted to isolate fungal species from black spot disease in rose and identify using morphological characteristics. Then, all the isolates were tested for pathogenicity to confirm Koch’s postulates. In this study, four fungal isolates have been successfully isolated from black spot disease in rose namely Rhizoctonia sp. (one isolate), Colletotrichum sp. (two isolates) and Penicillium sp. (one isolate). Based on pathogenicity test result using potato dextrose agar (PDA) plug technique, fungus UMTT27R (Penicillium sp.) showed highly pathogenic on rose’s leaves with disease severity (DS) = 88.89% followed by UMTT13R (Colletotrichum sp.) with DS=72.22%, UMTT21R (Colletotrichum sp.) with DS=66.67% and UMTT4R (Rhizoctonia sp.) with DS=61.11%. Correct identification of fungal pathogens is very important to strategize a proper method to control the black spot disease in rose cultivation
THE EFFECT OF TRAWL BOARD PULL-OVER LOAD ON SUBSEA PIPELINE OF OFFSHORE SABAH
Trawling is a method of catching fish in a large volume where fish net is pulled through water using one or two boats. Bottom trawling is where the nets are pulled over or close to seabed and can affect the subsea pipeline if found along the route. Therefore, the objective of this study was to determine the impact of pull-over to selected subsea pipelines in Sabah and Labuan waters. This study involved four oil and gas pipelines in Sabah and Labuan waters from the oil fields to shore terminals. The research started with obtaining data of the pipelines and specification of trawl gear in Sabah. Fishing trawler traffic data along the pipelines route was determined by AIS system and site observation to determine the density of the trawlers. Trawl gear pull-over load was calculated using DNV algorithm and the inputs were trawl gear specification ^and fishing trawl speed. The severity was based on pull-over load calculated and pipeline yield stress. Then frequency was based on AIS data and density of fishing trawl per area. Based on the comparison between trawl pull-over load and yield strength/stress, the effect of trawl board pull-over is considered as minor, which is the lowest in the severity index
STUDY ON AQUEOUS KAFFIR LIME EXTRACT AS TREATMENT AGENT ON FRESH TOMATO FRUITS
Tomatoes have a short shelf life thus they pose a big challenge for growers to maintain the quality of tomatoes to increase customer acceptance. In this study, fungi associated with tomato disease symptoms were isolated and the potential of kaffir lime aqueous extract was evaluated in maintaining post-harvest quality of tomatoes. For this purpose, healthy tomatoes were dipped in 10% aqueous kaffir lime extract before evaluating the post-harvest parameters namely weight loss and firmness. A fungus namely Rhizophus stolonifer was isolated from the symptomatic tomatoes. Subsequently, it was confirmed to be pathogenic on healthy tomato fruits with 100% disease severity. Application of aqueous kaffir lime extract showed that tomato fruits dipped in 10% aqueous kaffir lime extract recorded higher weight loss and higher firmness as compared to untreated tomato fruits. The results showed that treatment with this concentration of plant extract did not help to reduce the weight loss, but it retained the firmness of the tomato fruits stored at room temperature at 27+2oC. Higher transpiration process would lead to shrinkage, weight loss, changes in texture and appearance of the fruits. Therefore, this study suggested an increased concentration of aqueous kaffir lime extract as a treatment agent in order to have a better effect in maintaining the quality of tomato fruits
MECHANICAL AND PHYSICAL PROPERTIES OF BIO-NANOCOMPOSITE FILMS BASED ON CHICKEN SKIN GELATIN WITH DIFFERENT CONCENTRATION OF CHITOSAN NANOPARTICLES
Plastics packaging is non-biodegradable and risks to human health and environmental pollution. In contrast, gelatin-based film lack of desired mechanical, thermal and water vapour barrier properties. Thus, this study aimed to investigate the mechanical and physical properties of bio-nanocomposite films based on chicken skin gelatin with different concentration of chitosan nanoparticles (CSNPs). Gelatin/CSNPs film solutions with different CSNPs concentration (0-8%, w/w) were stirred at 45oC for 30 min and oven-dried at 45oC. Film characterization determination includes tensile strength (TS), elongation at break (EAB), Young’s modulus (YM), water solubility, water vapour permeability (WVP), film morphology and melting temperature (Tm). Results of the study indicated that incorporation of CSNPs significantly influenced film properties. The addition of CSNPs increased the TS and YM value, which lead to stronger films than the pure chicken skin gelatin films. However the addition of CSNPs decreased the EAB value. Furthermore, WVP and water solubility significantly decreased (p < 0.05) by the addition of 6% CSNPs. Morphology images showed that increased CSNPs reduced the film’s amorphous character, especially in high level, in which higher CSNPs (8%) resulted in the aggregation of particles in the composites. The nano-reinforcement films showed higher thermal stability as compared to pure chicken skin gelatin films. In conclusion, the film with 6% CSNPs showed the best formulation, as it demonstrated high in TS, YM and Tm value, while low in EAB, water solubility and WVP value compared to other films. The results presented in this study showed the feasibility of using bio-nanocomposite technology to improve the properties of biopolymer films based on chicken skin gelatin
THE PERFORMANCE ANALYSIS OF OPTICAL WAVE PROPAGATION FOR UNDERWATER WIRELESS COMMUNICATION
Underwater wireless communications refer to transmitting data in an unguided water environment by wireless carriers including acoustic, radio frequency (RF), and optical waves. Relative to acoustic and RF, the optical wave is more promising to offer higher bandwidth at a lower energy consumption rate. However, an optical wave has its challenges such as attenuation due to absorption, scattering and turbulence effects. Therefore, this work attempts to investigate the performance of lightwave propagation for underwater optical wireless communication (UOWC) using simulation and experimental approaches. First, the performance of optical waves was analyzed using MATLAB by simulating the light attenuation model which based on depth-dependent chlorophyll concentration. A depth profile that related to the surface chlorophyll levels for the range 0-4 mg/m3 was used to represent the open ocean. The simulation showed that the attenuation of light less affected for operating wavelength range of 450 – 550 nm. Further, an experimental set-up was developed which consists of a transmitter, receiver, and aquarium to emulate the UOWC channel. Three types of water including clear, sea and cloudy were tested to analyze their interaction with the light emitted by a light-emitting diode (LED) and a laser diode. The emitted light detected by the light sensor and the strength of an audio signal transmitted through the UOWC were measured using a light meter and sound meter respectively. The measured power was plotted against distance and the attenuation constant c was deduced through curve fitting method. The analysis showed irrespective of the light sources, UOWC in cloudy water suffered the highest attenuation relative to still clear and seawater. The received power emitted by laser was at least 41% higher than the LED. This study contributes to identify the potential and limitations of different operating schemes to optimize UOWC performance
DETERMINANT FACTORS OF ENTREPRENEURIAL INTENTIONS AMONG UNIVERSITY STUDENTS IN TERENGGANU
This study was conducted to assess how entrepreneurship experience, family background, and societal factors influence university students in Terengganu to embark on entrepreneurial activities. It cannot be denied that entrepreneurship exposure on campus may drive university students to engage in activities which may enhance their academic achievements in, boost confidence, and instill relevant qualities and skills to be successful graduates in the future. Such valuable experiences may be value added to the graduates. To see the impact of such an experience together with other relevant factors, this study has tested the relationship between entrepreneurship experience, family background, social factors and the subsequent effects among students of Universiti Malaysia Terengganu after graduation. The data were collected from 370 targeted respondents and were analysed using the multiple regression analysis. It was found that entrepreneurship experience and family background have significant relationships with entrepreneurship intention while societal factor was found to be insignificant
SEASONAL VARIATION OF PARTICLE NUMBER COUNT (PNC) AT THE COASTAL ENVIRONMENT IN PENINSULAR MALAYSIA USING BOOSTED REGRESSION TREES (BRTS)
The concentrations of airborne particulate matter (PM) is often measured as a mass concentration. However, the other way to express particulate matter is by using the Particle Number Count ([PNC]) concentrations. This study aims to analyse the seasonal variation of airborne particulate matter in terms of [PNC] by using R packages and the Boosted Regression Trees (BRTs) technique. The study was conducted at IOES, Universiti of Malaya in Bachok, Kelantan. The monitoring was important to understand the variability of seasonal effects due to different seasons. In this work, only the datasets for three seasons (Inter Monsoon, North East Monsoon and South-West Monsoon) were analysed involving 25,958 data. The air quality monitoring equipment involved was the particle counter Environment Dust Monitor GRIMM Model 180 and a weather station for recording the meteorological parameters. The data analysis was completed by using R software and its package for evaluating seasonal variability and providing the statistical analysis. The relationship between variables was studied by using the Boosted Regression Tree (BRT) technique. The interaction between independent variables towards the [PNC] in different seasons was discussed. The best setting result of BRT model evaluation R² is 0.22 (North-East Monsoon), 0.87 (Intern monsoon 1), and 0.59 for South West Monsoon which indicated that the model developed is acceptable except for NEM and intern monsoon seasons. Temperature (57 %) and wind direction (67%) were found to be the highest factor influenced by the formation of [PNC] concentrations in this area. Finally, good results indicated that BRT technique is an acceptable way to analysed air pollution data
PHYTOCHEMICAL SCREENING AND EVALUATION OF THE ENZYMATIC ANTIOXIDANT ACTIVITIES OF SELECTED Mangifera spp. LEAVES (ANACARDIACEAE)
A study was conducted on the chemical and biological properties of three different species of Mangifera i.e. Mangifera pajang, M. indica L., and M. kemanga leaves obtained from Pitas, Sabah. The aims of this study were to determine the presence of secondary metabolites as well as the antioxidative activities especially the catalase (CAT) and guiacol peroxidase specific activities (gPOD) in the leaves part of these three species. The extraction of these samples was carried out using three different polarities of solvents: hexane, ethyl acetate, and methanol. The total percentage of the crude extract of is 7.30% for M. pajang, 12.87% for M. indica and 7.98% for M. kemanga. Phytochemical screening was performed with various tests for each of the crude extracts. The results showed that these three species gave positive results for alkaloids, saponins, flavonoids, phenols, carbohydrates, phytosterols, and tannins metabolites. Based on the tests, CAT specific activities were significantly higher in the leaves of M. pajang with 4.35 ± 1.18 units/mg protein compared to M. indica L. and M. kemanga. The guaiacol peroxidase (gPOD) specific activities showed that M. indica L. has the highest activity with the value of 0.0047 ± 0.0004 units/mg protein
POTENTIAL OF AQUEOUS GINGER EXTRACT AS FRUIT COATING ON TOMATO
Soft fleshed tomatoes are easily damaged due to mechanical injuries. Later, the wounded tissue will be exposed to fungal infection thus fasten the deterioration rate and reduce the quality of tomato. The aim of this study was to evaluate the potential aqueous ginger extract to inhibit fungal pathogen that causes tomato wilt and its potential in delaying the weight loss of tomato fruits. For this purpose, in vitro antifungal assay using poison plate technique was used to observe the inhibition of fungal pathogen. Then, healthy tomato fruits were dipped in aqueous ginger extract before evaluated for the post-harvest quality such as weight loss and firmness. The results of this study show that 10% aqueous ginger extract can inhibit the fungal pathogen (Fusarium oxysporum) that causes tomato wilt with 13.57% inhibition. Through in vivo antifungal assay, tomato fruits dipped in this plant extract showed lower weight loss (14.44%) and higher firmness (1.7 N) as compared to untreated fruit, but the data were not significantly different. Therefore, manipulation of this extract was suggested to increase its antifungal properties or as eco-friendly coating to lengthen the shelf life of agricultural produces
Relationship of Condition Index and Reproductive Status of Black Snail, Fannus ater in Merchang Lagoon
Black snail, Faunus ater is an abundant species in Malaysia yet not many research have focused on its physiological and biological activities. This research aimed to assess the condition index (CI) and reproductive status based on the gonadosomatic index (GSI) for short-term duration. Samples were collected monthly from Merchang Lagoon, from November 2018 to January 2019. Four different types of condition indices equation were applied in this study and the results revealed that there were significant differences between four equations for measuring the CI (P=0.000). However, the result for the GSI shows no significant difference between three month of sampling (P>0.05). CI based on fresh weight measurement (Fww/Tww x 100) and dry weight measurement (Fdw/Fww x 100) reached its peak when GSI decreased. The rest of the trend for CI fluctuated and CI was not affected by GSI. Overall, this study concluded that, there were trends observed in CI and GSI for the black snails. However, it is suggested that longer term observation in future research is needed have a better understanding on the black snails