7 research outputs found

    Kecenderungan graduan wanita kejuruteraan terhadap pemilihan profesion kerjaya bukan jurutera

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    Penglibatan pelajar wanita memilih bidang kejuruteraan semakin meningkat, namun begitu bilangan yang menjadi jurutera profesional masih belum berada di angka yang membanggakan.Oleh itu, kajian ini dijalankan untuk; a) mengenalpasti faktor luaran yang mempengaruhi graduan wanita kejuruteraan dalam memilih profession bukan jurutera, b) mengenalpasti faktor dalaman yang mempengaruhi, c) mengenalpasti perbezaan yang signifikan faktor luaran di antara graduan kejuruteraan dari Fakulti Kejuruteraan Elektrik dan Elektronik (FKEE), Fakulti Kejuruteraan Mekanikal dan Pembuatan (FKMP) dan Fakulti Awam dan Alam Sekitar (FKAAS) di UTHM, d)mengenalpasti perbezaan yang signifikan faktor dalaman di antara graduan kejuruteraan UTHM.Kajian ini berbentuk deskriptif di mana responden terdiri daripada 153 orang graduan kejuruteraan UTHM. Data yang telah diperolehi melalui borang soal selidik dianalisis menggunakan perisian Statistical Package for Social Science (SPSS 20.0). Kajian rintis telah dijalankan dan nilai Alpha Cronbach yang diperolehi bagi setiap faktor adalah di antara 0.752 hingga 0.902.Hasil analisis mendapati faktor-faktor yang mempengaruhi graduan wanita kejuruteraan berada di tahap sederhana. Hasil kajian juga menunjukkan tidak terdapat perbezaan yang signifikan terhadap faktor yang mempengaruhi pemilihan kerjaya di antara graduan dari Fakulti Kejuruteraan Mekanikal dan Pembuatan (FKMP), Fakulti Kejuruteraan Elektrik dan Elektronik ( FKEE) dan Fakulti Kejuruteraan Awam dan Alam Sekitar (FKAAS). Oleh yang demikian, berdasarkan hasil dapatan kajian ini pengkaji menyarankan agar graduan wanita perlu meningkatkan motivasi diri dengan membina keyakinan dan kemahiran diri terhadap halatuju kerjaya di masa hadapan dengan jelas

    The efficacy of insecticides (Fendona and Malathion) against larvae and adult stages of Musca domestica

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    Malathion and Fendona® (alphacypermethrin) insecticides were tested against larvae and adult stages of house flies, Musca domestica Linnaeus. The percentage mortality of House flies larvae range between 0% and 100%at different exposed dose rate of tested insecticide. Probit analysis was used to determine the LD50. The value LD50 for malathion without food medium was 0.833 -l/larvae and treatment with food medium was 0.895 -l/larvaerespectively. The LD50 for Fendona® without food medium was 0.545 -l/larvae and 0.870 -l/larvae for treatment with food medium. The LD50 values for Fendona® in both treatment was lowers compared with malathion, which meansthat alphacypermethrin is more toxic than malathion. Different with the test on adult house flies, the knockdown time values for alphacypermethrin at KT50 is 9.876 minutes and KT95 is 20.495 minutes against female adult house fliesand were significantly lower than malathion (KT50 is 75.17 minutes and KT95 is 103.38 minutes respectively). Result also showed that a total of 1.0-l of Fendona® is reacting more effective than 1.0-l of malathion. Therefore, we canconclude that Fendona® is the most effective insecticide towards larvae and adult stage of M. domestica. The effectiveness of both chemicals was affected when treated larvae was in the rearing mediu

    Thermostable lipases and their dynamics of improved enzymatic properties

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    Thermal stability is one of the most desirable characteristics in the search for novel lipases. The search for thermophilic microorganisms for synthesising functional enzyme biocatalysts with the ability to withstand high temperature, and capacity to maintain their native state in extreme conditions opens up new opportunities for their biotechnological applications. Thermophilic organisms are one of the most favoured organisms, whose distinctive characteristics are extremely related to their cellular constituent particularly biologically active proteins. Modifications on the enzyme structure are critical in optimizing the stability of enzyme to thermophilic conditions. Thermostable lipases are one of the most favourable enzymes used in food industries, pharmaceutical field, and actively been studied as potential biocatalyst in biodiesel production and other biotechnology application. Particularly, there is a trade-off between the use of enzymes in high concentration of organic solvents and product generation. Enhancement of the enzyme stability needs to be achieved for them to maintain their enzymatic activity regardless the environment. Various approaches on protein modification applied since decades ago conveyed a better understanding on how to improve the enzymatic properties in thermophilic bacteria. In fact, preliminary approach using advanced computational analysis is practically conducted before any modification is being performed experimentally. Apart from that, isolation of novel extremozymes from various microorganisms are offering great frontier in explaining the crucial native interaction within the molecules which could help in protein engineering. In this review, the thermostability prospect of lipases and the utility of protein engineering insights into achieving functional industrial usefulness at their high temperature habitat are highlighted. Similarly, the underlying thermodynamic and structural basis that defines the forces that stabilize these thermostable lipase is discussed

    Enhancing the stability of Geobacillus zalihae T1 lipase in organic solvents and insights into the structural stability of its variants

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    Critical to the applications of proteins in non-aqueous enzymatic processes is their structural dynamics in relation to solvent polarity. A pool of mutants derived from Geobacillus zalihae T1 lipase was screened in organic solvents (methanol, ethanol, propanol, butanol and pentanol) resulting in the selection of six mutants at initial screening (A83D/K251E, R21C, G35D/S195 N, K84R/R103C/M121I/T272 M and R106H/G327S). Site-directed mutagenesis further yielded quadruple mutants A83D/M121I/K251E/G327S and A83D/M121I/S195 N/T272 M, both of which had improved activity after incubation in methanol. The km and kcat values of these mutants vary marginally with the wild-type enzyme in the methanol/substrate mixture. Thermally induced unfolding of mutants was accompanied with some loss of secondary structure content. The root mean square deviations (RMSD) and B-factors revealed that changes in the structural organization are intertwined with an interplay of the protein backbone with organic solvents. Spatially exposed charged residues showed correlations between the solvation dynamics of the methanol solvent and the hydrophobicity of the residues. The short distances of the radial distribution function provided the required distances for hydrogen bond formation and hydrophobic interactions. These dynamic changes demonstrate newly formed structural interactions could be targeted and incorporated experimentally on the basis of solvent mobility and mutant residues

    Characterization of aquilaria malaccensis callus cells using SEM and somatic embryogenesis associated genes identification

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    Aquilaria malaccensis or gaharu is one of Malaysia's top tropical resources that is being protected and conserved. Somatic embryogenesis is a plant tissue culture method used most extensively in commercial micropropagation systems and conservation purposes. This study aims to optimize callus induction techniques for somatic embryogenesis study using Scanning Electron Microscope (SEM) and Polymerase Chain Reaction (PCR) analysis. In this study, callus was induced on Murashige and Skoog's (MS) medium supplemented with a combination of plant growth regulators and optimized parameters (explant used, sterilization techniques, media content, pH media, plant growth regulators, incubation condition, and incubation temperature). The cells were subcultured for long-term callus maintenance and subjected to SEM analysis for somatic embryogenesis confirmation. Four set of genes associated to somatic embryogenesis (SERK, BBM, LEC1, and WOX) were studied based on National Centre for Biotechnology Information database and literatures. The data obtained were used for primer design and gene amplification using 3 different tissues (leaf, stem, callus).The highest frequencies of callus induction were observed on Murashikage and Skoog medium supplemented with 6-Benzylaminopurine and 1-Naphthaleneacetic acid together with optimized growth parameters. SEM analysis showed embryogenic characteristics in cells of the yellow compact calli evidenced by the presence of small and isodiametric cells. Only SERK gene was successfully amplified and enable to proceed with in silico analysis. This study provides fundamental results for genetic conservation effort of A. malaccensis related to somatic embryogenesis study

    Study on Soil Properties Towards Formation of High-Quality Agarwood Resin in Aquilaria Crassna

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    Agarwood has been used for its fragrance and medicinal properties in Asian culture for centuries. In recent years, agarwood gains its popularity in the west due to its usage in perfume formulation. Unfortunately, the supply does not meet the augmentation market demand. This is mostly because of depleting nature agarwood reservoir and lack of induction technique that can produce agarwood consistently in the plantation. In this study, we look into a case where artificial inducing technique successfully produced high quality agarwood. To assure its quality, agarwood chip was analysed by Gas Chromatography for its chemical profiles. Discovered compounds were identified as sesquiterpene group which also had been characterized as major agarwood compound listed on previous studies. Few compounds that are detected such as δ-cadinene (0.20%), jinkoh-eremol (22.09%), epi-α-cadinol (4.74%), agarospirol (3.75%) and others. Soil condition that contributes into this agarwood formation; soil analysis on physical properties, chemical properties and nutrients content of the soil have been analyzed. Based on the findings, soil condition is an important factor to successfully induced high quality agarwood

    Knotting terminal ends of mutant T1 lipase with disulfide bond improved structure rigidity and stability

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    Lipase biocatalysts offer unique properties which are often impaired by low thermal and methanol stability. In this study, the rational design was employed to engineer a disulfide bond in the protein structure of Geobacillus zalihae T1 lipase in order to improve its stability. The selection of targeted disulfide bond sites was based on analysis of protein spatial configuration and change of Gibbs free energy. Two mutation points (S2C and A384C) were generated to rigidify the N-terminal and C-terminal regions of T1 lipase. The results showed the mutant 2DC lipase improved methanol stability from 35 to 40% (v/v) after 30 min of pre-incubation. Enhancement in thermostability for the mutant 2DC lipase at 70 °C and 75 °C showed higher half-life at 70 °C and 75 °C for 30 min and 52 min, respectively. The mutant 2DC lipase maintained the same optimum temperature (70 °C) as T1 lipase, while thermally induced unfolding showed the mutant maintained higher rigidity. The kcat/Km values demonstrated a relatively small difference between the T1 lipase (WT) and 2DC lipase (mutant). The kcat/Km (s−1 mM−1) of the T1 and 2DC showed values of 13,043 ± 224 and 13,047 ± 312, respectively. X-ray diffraction of 2DC lipase crystal structure with a resolution of 2.04 Å revealed that the introduced single disulfide bond did not lower initial structural interactions within the residues. Enhanced methanol and thermal stability are suggested to be strongly related to the newly disulfide bridge formation and the enhanced compactness and rigidity of the mutant structure
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