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Schottky and Poole-Frenkel conduction mechanisms in ZrON/SiC system / Vanessa Lusus
Get PDFIn this work, the conduction mechanisms of Schottky Emission (SE) and Poole–Frenkel (PF) Emission for the ZrON/SiC system with a temperature range between 400 oC to 900 oC were analyzed. Understanding of the conduction charge mechanisms will help to estimate leakage characteristics of the ZrON/SiC system. Based on the J-E plot measured at different temperatures for 15 minutes, the obtained r2 was ranged between 0.90–0.98, which confirmed the data obtained complied with the standard SE model. Furthermore, the data plotted from the Effective Barrier Height Extracted from the SE plot showed the highest values o
Genomic and taxonomic studies of an antarctic psychrotolerant quorum quenching bacterium, Planococcus versutus L10.15T / See-Too Wah Seng
Get PDFQuorum quenching (QQ) has been suggested as an alternative to antibiotic treatments for pathogenic infections as it does not affect the viability of the pathogen and imposes minimum selection pressure promoting drug resistance. During an ecological survey for quorum quenching (QQ) bacteria from soil collected in Lagoon Island (Ryder Bay, Adelaide Island, Antarctica), a bacterial strain was isolated and identified as Planococcus species, L10.15T, based on 16S rRNA gene analysis. The genomic, phylogenetic, chemotaxonomic and phenotypic data obtained showed that L10.15T represents a novel species for which the name Planococcus versutus sp. nov. is proposed. Previously, QQ activity of L10.15T was studied, and it was confirmed to be capable of inactivating synthetic N-acyl homoserine lactones (AHLs) with acyl side chain lengths C4-C12, and active at a temperature as low as 4 °C. In this study, the gene responsible for the QQ activity of P. versutus L10.15T was identified and confirmed for its function in a gene expression study. The cold-active characteristics of the enzyme coded by this gene suggested that it belonged to a novel class of N-acyl homoserine lactonase, and we therefore term the gene as ‘autoinducer degrading gene from Planococcus sp.’ (aidP). The aidP gene was then cloned, and its gene product AidP enzyme, which is a novel class of AHL lactonase from the metallo-ß-lactamase superfamily gene, was characterized. Multiple sequence alignment analysis and amino acid composition suggested that the aidP gene encoded a cold-adapted enzyme. Interestingly, the aidP gene has only been detected in Planococcus spp. that have been isolated from Antarctica. Therefore, branch-site analysis was conducted on several Planococcus spp. branches within the phylogenetic tree of homologous gene, showing evidence of episodic positive selection for the aidP gene in cold environments. The gene showed homology to several metallo-β-lactamase proteins obtained from Bacteroidetes but not to any known AHL-degrading enzymes. Liquid chromotography-mass spectrometry analysis confirmed that AidP functions as an AHL-lactonase that hydrolyzes the ester bond of the homoserine lactone ring of AHLs. Furthermore, the effects of covalent and ionic bonding were demonstrated and the results indicate that Zn2+ is important for AidP activity in vivo. A pectinolytic inhibition assay using Chinese cabbage confirmed that this enzyme is a potential anti-quorum sensing agent. A phylogenomic study was also carried out for members of the family Planococcaceae. The results identified a misclassification of the genus Planomicrobium, which should be reclassified to Planococcus. The core genomic study revealed an essential set of survival genes shared across Planococcaceae. A positive selection assessment conducted on the 352 core genes identified 50 genes to be under high selection pressure in cold-adapted Planococcus spp. Finally, cold-adapted traits were identified in Planococcus spp., revealing information about cold-adaptation strategies in cold habitats
A corpus study of online reviews on The Suicide Themed Series 13 Reasons Why / Ummi Syafiqah Zaki
No full textThe present study aims to explore the reviewers’ perspectives on the suicide theme of 13 Reasons Why by examining the online reviews posted by these reviewers on Internet Movie Database (IMDb), Rotten Tomatoes, and Meta Critics. The corpus analysis tools adopted in the study are concordancing and keyword analysis. Concordancing is used to generate suicide-related concordance lines and to identify the evaluative items in the online reviews, while keyword analysis is used to explore the underlying key themes. Two frameworks applied to analyse these evaluative items and categorise them into positive and negative are evaluation in texts and discursive news values analysis (DNVA). The findings indicate that the suicide theme is perceived in negative light to a more significant extent compared to the positive light. The three main key themes that emerged from the findings and are discussed are misrepresentation of mental disorder, inaccurate portrayal of high school teenagers, and misleading message about teen social issues. The limitation of the study is the data used are limited to three review websites only while there are other websites that could contribute to the richness of the data
Gaya kepimpinan dan cabaran pegawai polis wanita / Norizzati Mohd Jailan
No full textPenyelidikan ini menggunakan pendekatan kaedah gabungan (mixed methods) yang dijalankan bertujuan untuk mengenalpasti serta mendapatkan kefahaman yang menyeluruh berkaitan amalan gaya kepimpinan wanita dalam menggalas tanggungjawab sebagai pegawai polis. Selain itu, kajian ini juga dijalankan bagi mengenalpasti cabaran yang dihadapi oleh responden sepanjang penglibatannya dalam profesion maskulin ini. Seramai 345 pegawai polis wanita Polis Diraja Malaysia (PDRM) yang terlibat dalam kajian soal selidik yang dijalankan termasuk temu bual bersama 10 responden diperingkat pegawai kanan dan pegawai rendah. Teori kajian ini memberi tumpuan kepada tiga gaya kepimpinan utama iaitu Kepimpinan Transformasi, Transaksi dan Laissez-faire. Instrumen Kepimpinan Multifaktor (MLQ) digunapakai sebagai instrumen soal selidik dan kaedah semi-struktur telah direka dan digunakan bagi sesi temu bual dalam memberikan perspektif responden berdasarkan pengalaman peribadi mereka sendiri. Data kuantitatif yang diperolehi telah dianalisis dengan menggunakan perisian Statistical Package For Social Science (SPSS) versi 22.0. Data analisis yang diproses melibatkan statistik deskriptif dan Ujian-t. Tema dan pengekodan perkataan pula dilakukan terhadap data kualitatif. Hasil kajian ini menunjukkan bahawa gaya Kepimpinan Transformasi merupakan gaya kepimpinan dominan yang diamalkan oleh responden secara keseluruhannya. Walaubagaimanapun, terdapat perbezaan yang signifikan terhadap gaya Kepimpinan Transformasi dan Transaksi berdasarkan pangkat responden. Melalui dapatan temubual yang dijalankan, polis wanita diperingkat pegawai kanan lebih mengamalkan gaya Kepimpinan Transformasi yang bercirikan ‘role model’(karismatik) dan meransang Intelek. Bagi pegawai yang berperingkat rendah pula, responden lebih tertumpu kepada ciri dimensi Kepimpinan Transaksi iaitu pengurusan pengecualian aktif. Selain itu, melalui hasil temubual tiga faktor cabaran utama responden telah diketengahkan iaitu (1) faktor individual; keyakinan diri, tanggungjawab yang lebih berat, ketahanan mental dan fizikal, (2) faktor keluarga; keutamaan dwi tanggungjawab, masa bersama keluarga yang terhad, perkembangan kerjaya, sokongan pasangan serta keluarga, dan (3) faktor organisasi; sukar berdiplomasi bersama anggota lelaki, dan kenaikan pangkat keperingkat atasan. Pada akhir perbincangan kajian, penyelidik juga memberikan cadangan kajian lanjut berkaitan kepimpinan pegawai polis wanita secara keseluruhannya
Syntheses, characterisations and electrochemical studies of nickel(II) and cobalt(II)-lIgand assisted cooperative complexes / Jeevithra Dewi Subramaniam
No full textA newly designed tetradentate ligand L1 (L1 = 3,6-bis(pyrazol-1-yl)-pyridazine) which offers multinucleation sites on its moiety structure has been prepared. The reaction of L1 with different molar ratio of nickel and cobalt salts lead to the formation of di- and tetranuclear complexes [NiII 2(L1)2(CH3CN)4](PF6)4 (1), [NiII 4(L1)4(μ-OH)4](ClO4)4 (2) and [CoII/III(L1)4(μ-CH3O)2(μ-O)2](PF6)3(NO3) (3), which served as the attempt to design of catalysts based on cheap and earth-abundant metals for carbon dioxide reduction. The presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base controls the nuclearity of the complex formation. In the absence of DBU, complex 1 was formed in dinuclear fashion whereas complex 2 and 3 formed tetranuclear fashion in the presence of DBU. The three complexes were structurally characterised by elemental analysis, nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared analysis (FT-IR), X-ray diffraction analysis, and voltammetry studies. Crystal structures revealed all complexes are centrosymmetric and adopted slightly distorted octahedral geometry. Complex 1 crystallises in monoclinic C2/c space group as the Ni(II) centre is octahedrally bound to L1 in a trans-isomer arrangement. Complex 2 crystallises in tetragonal I41/amd space group with four L1 and four hydroxy bridging ligands linked to Ni(II) centre in cisisomer arrangement. Complex 3 crystallises in orthorhombic Cmm space group with four L1, two methoxy bridging ligand and two oxo bridging ligands linked to Co(II/III) centre in cis-isomer arrangement. FTIR confirmed the L1 and bridging ligands were bound to the metal centre by exhibiting the shift a
Identification of peptide sequence to block dengue virus transmission into cells via In Silico and In Vitro Assays / Aathe Cangaree Arumugam
No full textDengue virus (DV) infection has become main public wellbeing concerns, affecting approximately 390 million people worldwide. This fact was reported by the World Health Organization. Yet, there is no commercial antiviral treatment for DV infection. Therefore, the development of potent and non-toxic anti-DV, as a complement for the existing treatment strategies, are urgently needed. Herein, we investigate a series of low molecular weight peptides inhibitors by aiming the cellular entry process as the promising approach to block DV infection. The peptides were designed based on previously reported peptide sequence, DN58opt (TWWCFYFCRRHHPFWFFYRHN), to identify minimal effective inhibitory sequence via molecular docking and molecular dynamics simulation studies. The in silico designed peptides were synthesized using conventional FMOC solid-phase peptide synthesis chemistry, purified by RP-HPLC, and characterized using LCMS. Later, they were screened for their antiviral activity. One of the peptides, AC 001, showed the best inhibitory activity towards DV2 with inhibition percentage of 40.34% ± 5.9%. This observation correlates well with the molecular mechanics-Poisson–Boltzmann surface area (MM-PBSA) analysis – AC 001 showed the most favourable binding affinity (-33.51 ± 5.11 kcal/mol) through 60ns simulations. Trough pairwise residue decomposition analysis, it was found that the key residues involved in the binding were mainly, Glu13, Arg350, Leu351, and Ser16 for the protein and F3, Y4, Y5, and R7 for AC 001. Hence, this work identifies the minimal peptide sequence required to inhibit DV replication and explains the behaviour of AC 001 towards DV2
Performance evaluation of lightweight normal and geopolymer foamed concrete using palm oil fuel ash as partial replacement of binder / Ahmed M. E. Alnahhal
No full textCarbon dioxide (CO2) emissions from Ordinary Portland Cement (OPC) have a detrimental effect on the environment and this had led many researchers to search for other alternatives in the form of sustainable cementitious materials. The depletion of natural resources and dumping the industrial by-products and waste materials are serious concern to our environment. This research focusses on the performance of using a palm oil industrial by-product, namely, palm oil fuel ash (POFA), as a partial replacement for OPC and fly ash (FA) in lightweight normal foamed concrete and lightweight geopolymer foamed concrete, respectively. Thus, using 10, 20, and 30% POFA as a replacement for OPC, and FA, foamed concrete was cast to achieve a target oven-dry density of 1300 kg/m3. In addition to the compressive and splitting tensile strengths, transport properties, such as water absorption, porosity, and sorptivity tests were carried out. The microstructural analyses were carried out using XRD, SEM, and EDS tests. Non-destructive tests – ultrasonic pulse velocity and electrical resistivity – were also performed. The results revealed that a replacement with 20% POFA produced comparable performance to other mixes and compressive strength of the lightweight geopolymer foamed concrete, with up to 30% POFA, was higher than the control, while conversely, for the POFA-based geopolymer mortar, the compressive strength was reduced with increasing POFA content. The highest compressive strengths recorded in the geopolymer foamed concrete with 20% POFA and in the control geopolymer mortar were 6.1 MPa, and 36.6 MPa, respectively. The geopolymer foamed concrete achieved 70% of its compressive strength within 3 days of the 28-day curing period. The results show that non-structural grade POFA based foamed concrete with a density reduction of about 36%
could be produced with 10-30% of POFA as binder replacement. Although the UPV test results show the foamed concrete as doubtful quality, the use of industrial waste as a sustainable material could be envisaged in such non-structural concrete. In general, the transport properties were mostly dependent on the oven-dry density. The SEM results showed micro-cracks when OPC was replaced with 30% POFA. Further, a slight reduction in the intensity of the peaks of the crystalline phases was observed when a higher quantity of POFA was used as cement replacement, while conversely, for lightweight geopolymer foamed concrete the peaks intensity increased, and the SEM images showed the foam agent distract the matrix compared to the control mixes. The optimum level of POFA to provide the silica and alumina required to produce sufficient geopolymerization gel to fill micro-voids was found to be 20%
Phenotyping of hypertensive heart disease and hypertrophic cardiomyopathy using personalized 3D modeling and cardiac magnetic resonance imaging / Chuah Shoon Hui
No full textDifferential diagnosis of hypertensive heart disease (HHD) and hypertrophic cardiomyopathy (HCM) is clinically challenging but important for treatment management. This study aims to phenotype HHD and HCM in 3D+time domain by using a multiparametric motion-corrected personalized modeling algorithm and cardiac magnetic resonance (CMR). 44 CMR data, including 12 healthy, 16 HHD and 16 HCM cases, were examined. Multiple CMR phenotype data consisting of geometric and dynamic variables were extracted globally and regionally from the models over a full cardiac cycle for comparison against the healthy models and clinical reports. Statistical classifications were used to identify the distinctive characteristics and disease subtypes with overlapping functional data, providing insights into the challenges for differential diagnosis of both types of disease. While HCM is characterized by localized extreme hypertrophy of the left ventricular (LV), wall thickening/contraction/strain was found to be normal and in synchrony, though it was occasionally exaggerated at normotrophic/less severely hypertrophic regions during systole to preserve the overall ejection fraction (EF) and systolic functionality. Additionally, we observed that hypertrophy in HHD could also be localized, although in less extreme conditions (i.e. more concentric). While fibrosis occurred mostly in those HCM cases with aortic obstruction, only minority of HHD patients were found to be affected by fibrosis. We demonstrated that subgroups of HHD (i.e. preserved and reduced EF: HHDpEF & HHDrEF) have different 3D+time CMR characteristics. While HHDpEF has cardiac functions in normal range, dilation and heart
failure are indicated in HHDrEF as reflected by low LV wall thickening/contraction/strain and synchrony, as well as much reduced EF
Optimal distribution system reconfiguration incorporating dg and variable load profile using artificial neural network / Hesham Hanie Youssef
No full textOptimal network reconfiguration is a common method used in distribution systems to ensure minimum power losses are always attained. This is very important task for achieving cost effective operation. Due to varying load demands, conventional network reconfiguration techniques have to be repeated whenever system loading changes to find a new configuration that has minimum power losses. This task is time consuming and ineffective approach for a real time application. Therefore, this research proposes an Artificial Neural Network (ANN) technique for optimal distribution network reconfiguration to overcome long processing time, mainly in load variation case. The proposed method involves; (1) Implement optimal network reconfiguration with variable load profile and DG generation using meta-heuristic techniques for ANN modelling (2) Designing an ANN model for optimal network reconfiguration (3) Train the proposed ANN model on the generated data using different split ratios for optimal network reconfiguration. The applied meta-heuristic techniques in this work are Evolutionary programming (EP) and Particle swarm optimization (PSO). To evaluate the performance of the proposed ANN method, simulation conducted on MATLAB were conducted on IEEE 16-bus, IEEE 33-bus and IEEE 69-bus system. The proposed network reconfiguration based on ANN significantly reduces the computational time to find the optimal solution while avoiding additional calculations. The results show that the proposed ANN technique is more than 90% faster than the conventional methods for varying load profile
Keluarga sebagai agen sosialisasi politik utama: Kajian kes di Kampung Istana, Batu Pahat / Marinayadzmin Mohd Radzif
No full textohor merupakan negeri kelahiran Parti Kebangsaan Melayu Bersatu atau lebih dikenali sebagai United Malays National Organisation (UMNO) pada tahun 1946. Penubuhan UMNO berasaskan semangat tinggi orang Melayu untuk mendapatkan kemerdekaan setelah lama dijajah.Hasilnya, UMNO kekal sebagai kerajaan pemerintah di peringkat negeri dan persekutuan seterusnya mendapat kepercayaan rakyat atas jasa membela hak serta kepentingan seluruh kaum di Malaysia. Walaubagaimanapun, UMNO gagal mengekalkan kubu kuat mereka terutamanya di Johor pada Pilihan Raya Utama yang ke 14 (PRU-14).
Kajian ini menumpukan kepada peranan institusi keluarga sebagai agen sosialisasi politik utama orang Melayu. Ia turut meninjau peranan ketua keluarga yang berpotensi mempengaruhi budaya politik ahli keluarga. Terdapat kemungkinan berlaku perubahan peranan, reversible role antara ibu bapa dan anak-anak kerana anak-anak pada zaman ini dilihat berpotensi mempengaruhi pandangan dan keputusan politik ibu bapa mereka. Perkembangan politik ini adalah seiringan dengan kemunculan agen-agen sosialisasi politik yang baru seperti Badan Bukan Kerajaan (NGO) serta media massa dalam mencorak orientasi politik masyarakat kini.
Oleh itu, kajian turut menyelidik sekiranya terdapat agen sosialisasi lain yang dilihat lebih berpengaruh dalam mempengaruhi pendirian komuniti Melayu dan tahap sokongan mereka terhadap UMNO kini. Akhir sekali, kajian akan mengenal pasti sekiranya sokongan orang Melayu terhadap UMNO dapat dikembalikan untuk menjamin kedudukan UMNO sebagai kerajaan pemerintah di peringkat negeri dan persekutuan pada PRU akan datang