Pusat Pengajian Sains Kimia - Tesis

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Binary And Ternary Complexes Of Β-Cyclodextrin With Isoniazid And Ethambutol: Characterization And Molecular Modeling Studies
(2023-09)
Goh, Soen Qeng
Long term intake of antituberculosis drugs will lead to severe adverse reactions that will ultimately deteriorate a patient’s health and well-being. Presently, it is known that supramolecular macrocycles such as cyclodextrins (CDs) are useful to enhance drug solubility and targeting mechanism while reducing drug dosage by providing many therapeutic benefits. With that, the possibility of formation of drug-CDs ternary inclusion complex was explored, whereby β-cyclodextrin (β-CD) was chosen as the supramolecular host carrier to accommodate two kinds of first-line antituberculosis guest drug molecules simultaneously, namely isoniazid (INH) and ethambutol (ETB). The inclusion complex of β-CD/INH/ETB was prepared using solvent evaporation method. Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), and 2-dimensional nuclear Overhauser effect spectroscopy (2D-NOESY) NMR were used to investigate the functional groups and structure of the complex. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to study the surface morphology and crystallinity changes during complex formation. Thermogravimetric analysis (TGA) was performed to investigate the thermal properties of the complex. FT-IR and both types of NMR results had revealed the successful penetration of both the drug molecules into the β- CD cavity. SEM images and XRD spectra had shown a drastic change in surface structure and reduction in crystallinity during complex formation, which had indicated successful formation of a new compound.
Characterization, Kinetics And Equilibrium Studies Of Paracetamol Adsorption On The Oil Palm Fronds (Opf) Cellulose Nanocrystals
(2022-02)
Idris, Nor Najhan
Pollution of water via pharmaceutical drugs such as paracetamol have been a highly concerning issue; and effective measures must be taken to treat these aquatic contaminants. Hence, the present study explored use of cellulose nanocrystals (CNC) isolated from oil palm fronds (OPF) through pre-treatments and acid hydrolysis as an environmental friendly adsorbent. The complementary analyses showed that the OPF CNC possesses a crystallinity index of 43.60 %, surface area (10.51 m2 g-1), and an aspect ratio of 19.98. Besides, the OPF CNC and OPF CNC-AC hydrogel beads have been successfully produced, optimised, and applied for paracetamol removal. The modification of OPF CNC-AC hydrogel beads with the commercial activated carbon (AC) has improved the BET surface area up to 85.19 m2 g-1. The adsorption studies of paracetamol onto OPF CNC and OPF CNC-AC hydrogel beads can be achieved at 60 g and 0.6 g of adsorbent dosage, respectively, at a pH 3 with a contact time of 170 min under room temperature. It was observed that the produced data fitted best with the pseudo-second order kinetic model and Freundlich isotherm model for characterising the adsorption of paracetamol onto OPF CNC hydrogel beads with a maximum adsorption capacity, qmax of 0.03 mg g-1. Meanwhile, for OPF CNC-AC hydrogel beads, the pseudo-second order kinetic model and Langmuir isotherm model showed the best correlation for the adsorption of paracetamol with a qmax value of 21.31 mg g-1. Therefore, the output from this study may suggest that OPF CNC and OPF CNC- xxiv AC hydrogel beads can be used as natural adsorbents for the removal of paracetamol waste.
Comparative Analysis Of The Bioethanol Yield And Components Of Sugar Extracted From Oil Palm Frond Under Different Prehydrolysis Treatments
(2021-11)
Dissanayake Mudiyanselage Rushan Lakshitha Bonuwan Diyanilla
this study was designed to produce a high bioethanol yield from OPF adopting eco-friendly and viable pretreatment methods, which are acid, autohydrolysis, alkaline, alkaline peroxide, and alkaline peroxide pretreatment coupled with acidified sodium chlorite (ASC) pretreatment
Cytotoxic Activity Of Isolated Alkaloids From The Bark Of Kopsia Terengganensis (Apocynaceae) And Corrosion Inhibition Studies Of Its Extract
(2023-09)
Hanafi, Wan Nur Huda Wan
The use of natural products in developing chemotherapy agents has shown a positive impact in the oncology field. Besides, they also showed a significant result as a corrosion inhibitor. Hence, this study aims to evaluate the cytotoxic activity and corrosion inhibition potential of the crude extract and isolated alkaloids from Kopsia terengganensis (K. terengganensis). The experimental involved extraction and isolation of alkaloids using different chromatographic methods, structural elucidation using various chromatographic techniques and evaluation of cytotoxic activity on HT-29 colorectal adenocarcinoma. Meanwhile, corrosion inhibition studies included weight loss studies, electrochemical studies, and surface analysis. The extraction and isolation process resulted in seven alkaloid compounds: eburnamine (90), isoeburnamine (58), eburnaminol (99), larutensine (100), eburnamenine (114), eburnamonine (56) and quebrachamine (148). In the cytotoxic activity, only compound 99 was able to suppress the growth of HT-29 with moderate activity (IC50 =75.8± 3.06 μM). For the corrosion inhibition potential, the alkaloid crude showed significant results (80-90% inhibition efficiency) in both weight loss and electrochemical studies. The inhibitor followed the Langmuir adsorption isotherm and the formation of an inhibitive film on the mild steel surface was proved in the surface analysis. In conclusion, the alkaloids from K. terengganensis were noteworthy to be investigated in both cancer and corrosion inhibition studies as it gives a positive result in the toxicity towards cancer cells and also mitigated the mild steel corrosion.
Design, Synthesis, Biological Evaluation, And Molecular Docking Studies Of Ortho-Carboxamido Stilbenes As Anti-Diabetic And Anti-Proliferative Agents
(2022-09)
Norhadi Bin Mohamad
A total of eleven ortho-carboxamido stilbenes (50a-50k) in 63-83 % yield have been synthesized using our modified Heck coupling method, and characterized using FT-IR, NMR, and HRMS. The research started with the Wittig reaction of 3,5-dimethoxybenzaldehyde (45) and methyltriphenylphosphonium iodide to form 3,5-dimethoxystyrene (46) followed by the Heck reaction with amide derivatives (49) under basic conditions to provide the corresponding (E)-stilbene derivatives (50a-50k). Five ortho-carboxamido stilbenes (50a-50e) were subjected to anti-diabetic studies on α-amylase and α-glucosidase enzymes.
Development Of An Electrochemical Sensor Based On Molecularly Imprinted Go/Zno/Ppy Composites On Pencil Graphite Electrode For Determination Of Andrographolide
(2021-12)
Rabia Tasaduq Hussain
This research highlights the development of an electrochemical sensor based on graphene derivatives with a molecularly imprinted polypyyrole (PPy) layer on a pencil graphite electrode (PGE) to detect andrographolide, which is a bioactive component of an ancient plant known as Andrographis paniculata. Conventionally, andrographolide detection based on tedious and heavy instrumentation.
Development of polymeric nanocomposite hydrogel using poly (vinyl alcohol) reinforced with organically modified layered double hydroxides for drug delivery systems
(2022-12)
Nor Jannah binti Mohd Sebri
A new advanced polymeric material with a potential for drug delivery systems was developed using the versatile poly (vinyl alcohol), PVA, enhanced with layered double hydroxides (LDH) organically modified with sodium dodecyl sulfate (SDS) and sodium isethionate (Ise) via co-precipitation method.
Diversity And Distribution Of Benthic Foraminifera In Mangrove Forests Of Penang Island
(2023-02)
Malek, Muhamad Naim Abd
Foraminifera is one of the diverse groups of organisms inhabiting mangrove environment, but local studies regarding benthic foraminifera are limited. Therefore, this study was conducted to examine the diversity and distribution patterns of the foraminifera species in mangrove forests around Penang Island, which were Teluk Tempoyak, Pulau Betong, and Kuala Sungai Pinang. A total of 648 surface sediment samples (N=18 points × 3 mangrove forests × 12 months) of 1 cm thick were randomly collected using scoops during the lowest spring tide. The sampling was conducted monthly from March 2017 to February 2018. The results showed low to moderate species diversity (H’ index: 0-1.4), typical of a mangrove environment. Overall, 29 benthic foraminifera species were identified, predominantly agglutinated with some combination of hyaline and porcelaneous tests. Benthic foraminifera in Pulau Betong mangrove recorded the highest species diversity (29 species), followed by Teluk Tempoyak (25 species) and Kuala Sungai Pinang (19 species). The species idetified are commonly found in mangrove swamps and in the coastal environment. Species distribution demonstrated significant variation among the different locations, zones, and seasonal factors in the three mangrove forests (p < 0.05).
Electrochemical Degradation Of Reactive Red 4 Using Graphite/Chitosan-Poly(Vinyl Chloride) Composite Electrodes
(2021-12)
Nadhra Hidayah Binti Mohd Halim
In this study, graphite/chitosan-poly(vinyl chloride) (C/Chi-PVC) composite electrode was used as anode to investigate the degradation of Reactive Red 4 (RR4) in the presence of graphite rod and sodium chloride (NaCl) respectively as cathode and supporting electrolytes.
Enhanced Photocatalytic Degradation Of Bisphenol A Under Visible Light Irradiation Using Nano Disc Rice Husk Ash Silica Templated Oxygen Doped Mesoporous Carbon Nitride And Carbon Dots Modified Graphitic Carbon Nitride
(2022-12)
Bukola, Shittu Fatimah
A series of oxygen doped mesoporous carbon nitride (O-MCN) was synthesized via thermal polymerization method. Another series of carbon dots modified graphitic carbon nitride (CDs/g-C3N4) was also synthesized via microwave assisted thermal polymerization method. Both were used for the photodegradation of bisphenol A (BPA) under visible light irradiation. The O-MCN were labelled as xO-MCN ( x = 0.1, 0.2, 0.3, 0.4 and 0.5 g glucose) whereas the CDs/g-C3N4 were labelled as yCDs/g-C3N4 (y = 0.5, 1.0 and 1.5 ml CDs). The Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption-desorption (NAD), UV–vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy, and X-ray photoelectron (XPS) spectroscopy were used to characterize the nanocomposites.
Evaluation Of The Insecticidal Activity Of Cashew (Anacardium Occidentale L.) Nut Shell Liquid Against Adult Bactrocera Dorsalis (Hendel) (Diptera: Tephritidae)
(2023-10)
Keita, Sainey
The Oriental fruit fly, Bactrocera dorsalis (Hendel), is one of the most notorious pests of agricultural fruits. It has been found to attack over 250 host plants, including commercial fruits and a wide variety of crops. The insecticidal activity of Cashew (Anacardium occidentale L.) nut shell liquid (CNSL) against adult B. dorsalis (Hendel) was investigated under laboratory and field conditions. Two extracting solvents, dichloromethane and hexane were used to extract the CNSL from the cashew nut shell. Contact toxicity, topical application and repellency tests were carried out in the laboratory. For both the contact and topical experiments, concentrations of 0.625, 1.25, 2.5, 5.0, 10.0 and 20.0 x 104 ppm were prepared, whereas 0.07, 0.14, 0.21, 0.28 and 0.35 μL/cm2 concentrations were prepared for the repellency tests. The LC50 values recorded after 24 hours of exposure for the contact toxicity tests of the dichloromethane extract was 4.66 x 104 ppm, whereas 6.58 x 104 ppm was recorded for the hexane extract, which showed the dichloromethane extract to be significantly higher with 1.32 times more lethal than the hexane extract against B. dorsalis (t-test, P<0.05).
Fabrication Of Bismuth Ferrite/Poly(O-Phenylenediamine) Based Carboxymethyl Cellulose Hydrogel And Its Photocatalytic Performance Towards Methyl Orange Under Direct Sunlight
(2022-10)
Nor Atilia Athira Binti Zaahari
CMC/BFO/PoPD (CBP) hydrogel film is successfully prepared by impregnating of the optimized BFO/PoPD into carboxymethyl cellulose (CMC) hydrogel with condition of molar ratio of BFO:oPD was 1:0.4 in 0.1 M HCl and the molar ratio of ammonium persulphate (APS) to oPD was 1.5:1 for degradation of methyl orange (MO) under direct sunlight
Fabrication Of Three Dimensional (3d)-Printed Electrodes-Based Thermoplastic Carbon Nanomaterials For Electrochemical Breast Cancer Dna Biosensor
(2023-08)
Omar, Muhamad Huzaifah
Three-dimensional (3D) printing or additive manufacturing is a promising technology to revolutionise traditional manufacturing methods. Nowadays, numerous studies have utilised 3D printing technology to replace conventional electrodes in the fabrication of electrochemical sensors and biosensors due to its low cost, rapid prototyping, and flexibility in design. The main aim of this study is to explore the 3D-printed electrode’s potential as an electrochemical biosensor for breast cancer gene (BRCA1) detection. The first section focuses on the electrochemical performances of 3D-printed polylactic acid/carbon fiber (PLA/CF) electrodes. A novel electrochemical treatment using the differential pulse voltammetry (DPV) technique in hexaammineruthenium (III) chloride (RuHex) solution is proposed. Electrochemical characterisations revealed that the DPV-RuHex electrochemical treatment significantly improved the electrochemical performance of the 3D PLA/CF electrode. Furthermore, field emission scanning electron microscopy (FESEM) micrographs demonstrated that more PLA layers degraded after the treatment, which increased the electrode’s electroactive surface area. The second part investigates the effect of DPV treatment in RuHex and sodium hydroxide (NaOH) solutions on the 3D-printed PLA/graphene (PLA/G) electrode. The electrochemical analyses revealed no significant difference between the two treatments.
Functional Cellulose Nanocrystal-Alginate Hydrogel Beads Prepared From Oil Palm Fronds For The Adsorption Of 4-Chlorophenol In Aqueous Solution
(2023-01)
Tuan Sherwyn Hamidon
The present study aimed to develop efficient cellulose nanocrystal-based hydrogel beads in treating simulated wastewater contaminated with 4-chlorophenol. Initially, cellulose nanocrystals (CNCs) were extracted from oil palm fronds (OPF) employing the sulphuric acid hydrolysis method along with various pretreatments.
Genetic Diversity Of The Beetle, Paederus Fuscipes Curtis (Coleoptera: Staphylinidae) And Its Symbiotic Diversity With Pederin Polymorphism Based On 16S Rrna Metagenomics Profiling
(2023-02)
Teoh, Miao Ching
Paederus rove beetles are known to carry the pederin toxin that causes linear dermatitis when crushed on skin. The toxin is produced by an unculturable Pseudomonas sp. harboured by the female Paederus beetles. Pederin polymorphism has been observed several Paederus and Paederidus beetle species wherein the (+) female beetles carried the toxin pederin and (−) females lacking this toxic amide. It has been stated that the (−) female Paederus beetles are infected with more bacterial species than (+) females, but the microbial profiles between the two female groups were not revealed. Besides, the association of pederin polymorphism with the host beetle’s genetic is yet to be investigated. Herein, the objectives of this dissertation are to investigate the microbial profile of the two groups of P. fuscipes beetles, and to study the host beetle’s mtDNA COI in association with pederin polymorphism. Pederin polymorphism studies on P. fuscipes beetles were carried out by PCR detection of pederin (ped) biosynthesis genes. The female beetles were then subjected to 16S rRNA amplicon sequencing and mtDNA COI analysis. This study also attempts to culture and isolate the pederin-producing bacteria.
Green Synthesis Of Iron Nanoparticles From Moringa Oleifera Leaf Extracts: Characterization And Application For Diesel Range Organics And Nitrate Removal
(2022-08)
Ubah Promise Chima
Ethanolic extract (EtOH-MOL) and water extract (H2O-MOL) of Moringa Oleifera (M. Oleifera) plant leaves were used in this study for the biosynthesized iron nanoparticles (BINPs). M. Oleifera is a non-toxic tropical plant known for its medicinal properties and good antioxidant content. Iron sulphate heptahydrate was used as the metal precursor for the formulation of BINPs.
Green Zinc Oxide-based Photocatalysts: Preparation, Characterization And Photocatalytic Study For The Degradation Of Dyes Under Visible Light Irradiation
(2023-08)
Abdullah, Fatin Hazirah
There is a scarcity of literature on the fabrication of zinc oxide (ZnO) photocatalyst using a greener biosynthetic route and bio-based materials, with a primary focus on improving the reusability, collection, and recovery of the photocatalyst. Besides, ZnO suffers from low photodegradation efficiency due to low visible light absorption and high recombination of photogenerated charge carriers. In this study, green ZnO-based photocatalysts were successfully synthesized at room temperature using environmentally friendly, low cost, and facile methods. The work highlights the combination of valorization of banana peel (BP) waste and natural rubber (NR) biopolymer to develop effective, economic, and sustainable photocatalysts with good reusability for high removal of dyes. The photoactivity of these photocatalysts were evaluated by the degradation of Methylene Blue (MB) dye under visible light irradiation. The ZnO nanoparticles were initially synthesized using BP extract as reducing and capping agents. The best conditions for green synthesis of ZnO were pH 12, 1 mL BP extract, 0.02 M zinc acetate dihydrate, 3 h synthesis time, and 60 °C temperature. The biosynthesized ZnO exhibited advanced properties and superior photocatalytic performance than the chemically synthesized ZnO, which was prepared for comparison purposes.
Heterogeneous Fenton Degradation Of Ofloxacin In Aqueous Solution Using Fe3O4-Zeolite, Fe3O4-Montmorillonite And Fe3O4-Montmorillonite Alginate Composites
(2023-04)
Dhahawi, Alamri Rahmah
The primary aim of this study is to develop an economical, stable and effective heterogeneous catalyst for wastewater remediation via the Fenton oxidation process. Fe3O4 can effectively activate H2O2 to produce hydroxyl radicals, but the particles agglomerate easily. To solve this problem, Fe3O4-zeolite (FeZ) and Fe3O4-montmorillonlite (FeM) composites were synthesized via a facile co-precipitation method and characterized using various techniques. The performance of each of the catalysts was evaluated via the Fenton degradation of ofloxacin (OFL), an antibiotic and a recalcitrant pollutant because of its high activity and poor biodegradability. The effect of parameters such as amount of Fe precursor, catalyst dosage, initial solution pH, initial OFL concentration, different oxidants, H2O2 dosage, reaction temperature and inorganic salts on the OFL removal percentage were investigated. Loading of Fe3O4 onto zeolites resulted in the formation composites with higher surface area and pore volume. Experimental results revealed that as much as 88% OFL from the aqueous OFL solution 20 mg/L and 51.2% total organic carbon (TOC) could be removed in 120 min using FeZ-8 catalyst at the optimum condition. Since montmorillonite is capable to adsorb OFL at higher concentration, the OFL initial concentration was adjusted to 50 mg/L for FeM.
In Silico And In Vitro Characterisation Of Peptide Binding Sequence Of Trim25 Cc Domain Towards 14-3-3 Sigma Protein
(2023-09)
Chiang, De Chen
14-3-3σ protein is the most diverged isoform among the seven isoforms of the 14-3-3 protein family. Unlike other 14-3-3 isoforms, its downregulation was demonstrated in various cancer and tumour development, which is in line with its function as an adaptor protein controlling cell cycle and development. TRIM25 is an E3 ubiquitin ligase that largely responsible for ubiquitin-mediated protein degradation. Interestingly, 14-3-3σ-TRIM25 interaction leads to 14-3-3σ ubiquitination and subsequent proteasomal degradation. Their exact interacting peptide sequence, however, has yet to be identified. The present study aimed to identify the peptide binding sequence of TRIM25 protein towards 14-3-3σ protein. A total of 5 peptides were identified from in silico bioinformatic analysis (motif search and multiple sequence alignment) for subsequent binding assay. The peptides were either purchased commercially, or synthesised in-house using Fmoc SPPS method, followed by purification using semi-preparative LC and mass-validated with LC-MS. 14-3-3σ protein was successfully expressed using E. coli expression system and purified with affinity chromatography. Interactions between the 6 peptides identified previously and the 14-3-3σ protein expressed were tested with 1H CPMG NMR assay, of which Peptide 1 with sequence 402KLPp(T)FG407 demonstrates the highest binding affinity to 14-3-3σ protein. Competitive CPMG NMR assay of Peptide 1 with Peptide 6 (a known 14-3-3σ binder) revealed substantial binding competition, suggesting that Peptide 1 shares similar binding site with Peptide 6 at the amphipathic pocket
Interfacial enhancement of mixed matrix membrane using ionic liquid for co2 separation
(2020-04-10)
Ahmad, Nor Naimah Rosyadah
The use of mixed matrix membrane (MMM) appears to be a promising approach in CO2 separation application due to the synergistic effects of polymer and inorganic materials. However, poor compatibility between inorganic particles and polymer often results in interfacial defects that reduce the MMM gas separation performance. In this study, asymmetric MMMs comprises of polysulfone (PSf) and SAPO-34 zeolite were fabricated via dry-wet phase inversion. The loading of SAPO-34 zeolite in the MMM formulation was first varied from 5 to 15 wt.% to study the effect of zeolite loading to the characteristics of the MMMs and CO2 gas separation performance. Increasing the zeolite loading has enhanced the CO2 permeance of the MMM but reduced the CO2/N2 selectivity as compared to the neat PSf membrane. The incorporation of SAPO-34 zeolite in the PSf membrane has resulted in the voids formation at the polymer/filler interface contact as shown by scanning electron microscopy images. Ionic liquid (IL) which selective towards CO2 was used in this study to modify the MMM by sealing the interface defects in the membrane. Two different approaches namely premodification and post-modification were applied in the MMM modification. Results showed that the post-modification method with IL has improved both polymer/zeolite interface contact and gas separation performance of the MMM as compared to the premodification approach. The post-modification method was further explored by studying the effects of IL concentration, zeolite loading, solvent and IL properties. It was found that the post-modification of the MMM incorporated with 5 wt. % zeolite loading has enhanced the CO2/N2 selectivity about 820 % over the unmodified MMM by increasing the concentration of the IL/ethanol solution from 0.2 to 0.4 M. The CO2/N2 selectivity can also be increased when more polar solvent such as methanol was used in the post-modification of MMM involving low IL concentration (0.2 M). The CO2 permeance and CO2/N2 selectivity of IL-modified MMM was improved to 4.93-7.19 GPU and 26.63-35.21 respectively by using IL with large molecular weight since the reduction in zeolite porosity could be minimized. Analysis of the gas transport parameters revealed that the incorporation of IL into the MMM has increased the CO2 solubility of the membrane but the improvement in the CO2/N2 selectivity was mainly contributed by the diffusivity selectivity. The gas separation performance for the IL-modified MMM was observed to sustain when being exposed to the humid gas condition. Thus, the post-modification approach of MMM using IL can be as an alternative strategy in membrane development for CO2 separation application.

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