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Transcriptomic responses to coaggregation between oral bacteria / Naresh V R Mutha
Get PDFCell-cell interactions between genetically distinct oral bacteria form macroscopic clumps known as coaggregates. These interactions, termed coaggregation contribute to the formation of highly structured multispecies communities in oral cavity, known as oral biofilms. Individual species also compete and collaborate with other neighboring species through metabolic interactions allowing growth of other species by coaggregation. This study involves the mixing of selected pairs of oral bacteria to form coaggregates and quantifying differential gene expression levels in each pair in comparison with mono-species coaggregation. The dual RNA-Seq approach made it possible to see how bacteria respond to one another leading to different metabolic interactions for each pairing in coaggregation. In this perspective, Streptococcus gordonii was coaggregated with selected oral bacteria. The aim was to analyze transcription data from separate pairings of Streptococcus gordonii with Fusobacterium nucleatum (first pair), Veillonella parvula (second pair) and Streptococcus oralis (third pair) to understand gene regulation mechanisms involved in coaggregation. The data analysis involved comparison of mRNA profiles in mono-species cultures vs coaggregates. Significant differentiallyexpressed genes and pathways in S. gordonii among all three bacterial pairings were compared to determine whether common mechanisms exist between oral bacterial coaggregates analyzed in this study. In the first pairing a total of 119 genes differentially expressed in S. gordonii following coaggregation with F. nucleatum whereas only 16 genes had shown differential expression in F. nucleatum. In both species, genes involved in amino acid and carbohydrate metabolism were strongly affected by coaggregation. In particular, one 8- gene operon in F. nucleatum encoding sialic acid uptake and catabolism was up regulated to 2-5 fold following coaggregation. In S. gordonii, a gene cluster encoding functions for phosphotransferase system-mediated uptake of lactose and galactose was down regulated up to 3-fold in response to coaggregation. In the second pairing a total of 272 genes differentially expressed in V. parvula, including 39 genes in oxidoreductases processes. In S. gordonii, there was a high degree of inter-sample variation. Nevertheless, 69 genes were identified as potentially regulated by coaggregation, including two phosphotransferase system transported and several other genes involved in carbohydrate metabolism. In third pairing a total of 22 genes in S. oralis and 72 genes in S. gordonii were regulated following coaggregation. A 6-gene operon encoding tryptophan in S. oralis was down regulated to 1.5-fold following coaggregation whereas mainly transporter genes in S. gordonii were up-regulated. A large cluster encoding transporters and two component (NisK/SpaK) regulatory system was upregulated to 2-4 folds in coaggregation
A comparative study on musicians and non-musicians’ affective response in music listening / Loh Wai Neng
Get PDFThis study examined the affective responses in the music listening among undergraduates’ student using Circumplex Model of Emotion (Russell, 1980). The purpose of this study was to investigate the affective responses of undergraduate music major and non-music major students in music listening to four different music genres, which were classical music, romantic music, atonal music and experimental music. A study involving of 123 participants from undergraduate music major and non-music major students in Klang Valley area was conducted using google form. By using SPSS to tabulate the data, the result showed that there were no major differences between both musicians and non-musicians when they listen to four different types of music genres. For classical music and romantic music, emotion responses for both musicians and non-musicians are towards to high valence, whereas for atonal music and experimental music, the emotion responses for both musicians and non-musicians are towards to low valence
From social justice to landscapes: The politics behind the woodblock prints of See Cheen Tee / Eugene Foo Shyang Eu
Get PDFSee Cheen Tee produced over 50 pieces of woodblock prints in the mid-1950s to the mid-1960s. This research seeks to investigate the politics behind these woodblock prints by studying social and political climate of the time it was produced. Politics in this research must be understood in the context of power relations that includes both formal and informal, organizations or individuals, and is not limited to the generalized notion of the activities of governmental bodies. His work is compared and contrasted against other artworks such as woodblock prints produced during the Chinese Modern Woodcut Movement, paintings by first generation Nanyang-style artists and even some of his contemporaries. The research approaches his woodblock prints according to themes that are observed to be prevalent in the subject matter of the prints, namely Social Justice, visualizing nationhood, the exotic native Other, and feminine figures. This wide range of subject matter required several methodologies and theoretical frameworks to be consulted. This included social political historical data, Post-Colonial theory, the concepts of the Other, and also gender politics. The analyses of his works revealed that his early works were closely related to Social Justice themes, and engaged with formal politics and perceivable formal structures of power. But as his subject matters veered towards more genre scenes and landscapes, the workings of politics also delved into more personalized areas of informal politics, that deals with personal visions of nation-building, negotiating with native ethnicities as the other, and the gaze of the artist based on gender. See’s work demonstrates a sort of sensitivity to these subject matters that reveals an ambivalent quality. This research further dismantles the notion that woodblock prints are necessarily related to the workings of formal politics and that it is an equally pliable medium that allows for very unique representations capable of even creating fine nuances that convey more complex narratives
Graphene oxide gold nanostructure based surface enhanced raman scattering DNA biosensor for the detection of meat species / Md. Ibrahim Khalil
Get PDFAuthentication, detection and quantification of the ingredients, and adulterant in the food, meat and meat products are of high importance in current days. However, the conventional meat species detection techniques based on lipid, protein and DNA biomarkers have been confronting challenges due to the poor selectivity, sensitivity, and unsuitability for processed food products or complex food matrices. Hence, nanoparticle based DNA biosensing strategies have attracted the most interests and considered as one of the best alternatives to conventional strategies. Among these, surface enhanced Raman scattering (SERS) has gained the substantial acceptance as an excellent, fast and ultrasensitive sensing technique due to its ability to produce molecule specific distinct spectra, narrow spectral bandwidth and multiplexing ability. However, the performance of the SERS DNA biosensor relies on the DNA probe length, platform composition, presence and position of Raman tags and the chosen sensing strategy. Herein, it was demonstrated for the first time SERS DNA sensing for the detection meat species using short-length DNA probe and two different strategies of Raman tag attachment either co adsorbed with or intercalated in the DNA probe sequences. Moreover, SERS-active dual platforms comprising of graphene oxide-gold nanoparticles (GO-AuNPs), graphene oxide-gold nanorod (GO-AuNR), and AuNPs were used in different combinations. At the first sensing strategy, GO-AuNP functionalized with capture probe 1 (CP1) and AuNPs with co-adsorbed CP2 and Cy3 were used to fabricate the SERS biosensor for the quantitative detection of the Malayan Box Turtle (MBT). Hybridization mediated coupling of the two platforms generated the huge amplified SERS signal which in consequence facilitated to achieve a greater sensitivity with a limit of detection (LOD) of 10 fM (synthetic target DNA) and 100 fM (real sample). In the second strategy, a uniquely
designed Raman tag (ATTO Rho6G) integrated signal probe (SP) sequence immobilized AuNPs and the CP DNA functionalized GO-AuNR were utilized to detect the pig species. This biosensing approach showed an outstanding sensitivity with an LOD of 100 aM as well as validated with DNA extracted from pork sample (LOD
– 1fM). Finally, a duplex SERS DNA biosensor was fabricated following the same strategy using Cy3 and ATTO Rho6G intercalated SP sequences specific to MBT and pig species respectively as well as GO-AuNPs and AuNPs as sensor platforms for the simultaneous detection of both species. In the presence of the target DNA sequences, covalent linking of the CP functionalized GO-AuNPs and SP functionalized AuNPs triggered the huge SERS signal enhancement due to the multi-component agglomeration. The duplex DNA biosensor exhibited an excellent sensitivity with an LOD of 10 fM for the synthesized target DNA and 100 fM for real sample. Moreover, the fabricated SERS biosensors showed an outstanding selectivity and specificity to differentiate the DNA sequences of the closely related non-target species and the target DNA sequences with single and three nucleotide base-mismatches. The developed short-length DNA conjugated dual platforms based SERS biosensors proved as a selective, sensitive and convenient technology for the detection of single and dual species, hence could be universally applicable for the versatile applications and opted for the simultaneous multiplex detection
Synthesis and characterization of hybrid organic coating system to reduce thermal degradation of solar cells / Farah Khaleda Mohd Zaini
Get PDFThermal-decreasing hybrid organic coatings were developed for crystalline solar cells by using two types of binder systems; namely Aminopropyltriethoxysolution (APTES) / Methyltrimethoxysilane (MTMS) binder system (labelled as B1) and Methyltrimethoxysilane (MTMS) / nitric acid (HNO3) binder system (labelled as B2). Three types of nanoparticles; Titanium dioxide, TiO2 (Anatase), Zinc oxide, ZnO and Tin dioxide, SnO2 nanoparticles with different weight percentage were introduced inside each binder system namely; 20 wt%, TiO2 (T1B1 coating), 60 wt% TiO2 (T2B1 coating), 20 wt% ZnO (Z1B1 coating), 60 wt% ZnO (T2B1 coating), 20 wt% SnO2 (S1B1 coating) and 60 wt% SnO2 (S2B1 coating) for B1 binder system and 20 wt%, TiO2 (T1B2 coating), 60 wt% TiO2 (T2B2 coating), 20 wt% ZnO (Z1B2 coating), 60 wt% ZnO (Z2B2 coating), 20 wt% SnO2 (S1B2 coating) and 60 wt% SnO2 (S2B2 coating) for B2 binder system. This work highlights the effects of nanoparticle coating systems on the surface temperature of solar cells along with several structural and electrical studies. It is found that B1 coating systems showed a better performance in decreasing the surface temperature of solar cells compared to B2 coating systems. The introduction of nanoparticles inside the binder systems further reduced the surface temperature of solar cells from 55.75 °C (non-coated solar cell) at 60th minute of exposure under standard test condition (STD) of 1000 W/m2 irradiation and room temperature of 25°C. Under the same condition, S1B1 nanoparticle coating records the lowest temperature of 42.66°C for B1 binder system and Z1B2 coating system records a reduced temperature of 48.82°C for B2 binder system. Furthermore, the fill factor of solar cells was also improved by approximately 0.1 or 16.67% with binder coating systems (B1 and B2 coating systems) and about 0.2 or 33.33% with nanoparticle coating systems (T1B1, T2B1, Z1B1, T2B1, S1B1, S2B1, T1B2, T2B2, Z1B2, Z2B2, S1B2, S2B2 coating systems)
Synthesis and in vitro studies of polycaprolactone-coated superparamagnetic iron oxide nanoparticles for magnetic hyperthermia therapy / Ziba Hedayat Nasab
Get PDFResearch has garnered a great interest in utilization of superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic nano-heating agents in hyperthermia cancer therapy by profiting from high apoptosis vulnerability of cancer cells at elevated temperatures. However, low oxidation resistance and high agglomeration tendency negatively affect magnetic characteristics of nanoparticles and subsequently their clinical efficiency. Particle surface modifications are potential approaches to endow SPIONs a range of desirable properties including high colloidal dispersity, low aggregation tendency, cytocompatibility, and high oxidation resistance. Currently, polymer coating has led to decrease magnetic hyperthermia efficiency through formation of intermediate layer between nanoheating agents and targeted cells. This research aimed to stabilize the negatively-charged SPIONs through a cationic surfactant, followed by surface coating using thermosensitive biopolymer to improve particles dispersibility, cytocompatibility, functionality and in-vitro cytotoxicity under hyperthermia condition. In this study, synthesis condition was optimized via investigating the effects of two alkaline reagents as well as two synthesis environments on various SPIONs characteristics. Thereafter, the possibility of synthesizing SPIONs using a single iron precursor was examined to decrease synthesis complexity, save expenses, eschew wasting materials and improve their properties. The SPIONs were then stabilized by the surfactant, followed by focusing on preparation of biopolymer-coated SPIONs and assessing their physicochemical, thermal and magnetic properties as well as in-vitro hyperthermia performance on human hepatocellular carcinoma (HepG2) cells under the exposure of an alternating magnetic field (AMF). The obtained resultsindicated that SPIONs could synthesized using a single precursor through precipitation protocol under oxidative experimental condition with significant improvement in crystallinity and magnetic features in comparison with those
of SPIONs produced using two precursors. Investigation of the surfactant showed its negligible effect on magnetic behaviors while enhanced dispersibility in a controlled micellar conformation, then biopolymer core-shell SPIONs showed an improvement in hyperthermia efficacy via their enhanced stealth characteristics to avoid rapid clearance by immune system and improved activity towards AMF due to melting of protective shell under hyperthermia condition. The findings indicated that combination of SPIONs and AMF rendered SPIONs highly cytotoxic to liver cancer cells; therefore, they would be a step-change into research as potential targeted nanoheating agent for new therapeutic options
An instrumental study of front oral monophthongs in Kensiu / Adilah Azizan
Get PDFThis paper acoustically examines the front oral vowels of Kensiu, a highly endangered Austroasiatic language spoken in Peninsular Malaysia. Although there have been initial studies on the phonology of Kensiu, (Bishop, 1996; Burenhult, 2001), these are mainly on the variety spoken in Thailand. This far, there is a lack of studies especially those based on the acoustic analysis. The changes in the sounds of Kensiu are likely to have taken place with increasing contact with the local Malay community in Kedah where the only Kensiu village is located. This paper aims to fill the gap by examining the acoustic properties of front oral monophthongs in Kensiu using a formant frequency model to examine the characteristics of these monophthongs and if there is vowel conflation between these monophthongs. Five female Kensiu native speakers aged between 50 to 62 years old from Kampung Siong in Lubuk Lengong located in Baling, Kedah were recorded. Data were obtained by showing the speakers pictures containing words with the target vowels. Based on measurements of the first formant (F1) and second formant frequencies (F2), the findings suggest that there may be only four front oral vowel phonemes in the Kensiu spoken in Kedah compared to five in the variety spoken in Yala, Thailand. This is due to the conflations of neighbouring vowels as well as possible influence from Malay. This study contributes to our understanding of the Kensiu sound system
Evaluation of anti-cancer function in natural killer cells generated from rat hematopoietic stem cells / Alireza Pirahmadian
Get PDFNatural killer cells (NK) cells are lymphocytes and they are the most important key constituent of mammalian immune system against cancer tumour cells. The genome of NK cells is categorically divided to inhibitory and activator genes that code ligands on the surface of NK cells. Indeed, these ligands are cancer tumour cells destroyer arms of the NK cells. On the other hand, hematopoietic stem cells (HSCs) are the origin of all blood cells, derives from BM and mature to immune cells. NK cells cannot defeat CTCs on their own. The main reason is their population (numbers are low), they cannot derive from HSCs as fast as CTCs division rate, and that is why external treatments have to be used to treat cancer. This project, designed to promote and give potency to immune system against CTCs without relying on external treatments. To obtain this goal, three specific genes of NK cells, cloned in BMHSCs and differentiated the stem cells to NK cells. The success of the colonization has been examined by western blot and flow cytometry and in term of functionality of newly generated NK cells the cytotoxicity has been examined by MTT assay and Live and Dead assay and the apoptosis ability of newly generated NK cells have been examined by RARP Cleavage and Caspase 3/7 assay. The results and data approve that the generated NK cells from BMHSCs are able to destroy cancer cells
Fractionation and characterization of extracted lignin from oil palm empty fruit bunch using synthesized deep eutectic solvents / Tan Yee Tong
Get PDFDeep eutectic solvent (DES), a new generation green solvent has been introduced as an alternative pretreatment solvent due to its ability for lignocellulosic biomass fractionation and lignin extraction. Numerous types of compounds can be adopted as DES constituents, which has resulted in abundant variation of DES with varying properties. Selection of the suitable chemical compound category is therefore essential for optimum DES performance. However, investigation on the performance comparison between the different DES categories is lacking. In addition, despite its widely acknowledged effectiveness in biomass fractionation, the properties of DES-fractionated biopolymers, especially lignin are not well understood. Hence, this project focused on identifying the best performing DES constituents for lignocellulosic biopolymer fractionation and lignin extraction from oil palm empty fruit bunch (EFB). Subsequently, the properties of DES-pretreated EFB solid and DES-extracted lignin (DEEL) were elucidated to assess their potential for downstream conversion. EFB was selected as the source of biomass in this study due to its presence as one of the most abundant agricultural wastes in Malaysia and its rich lignocellulosic biopolymer content. The first stage of DES selection started with identifying the suitable pH range of the solvent. Acidic DES demonstrated great fractionation ability to achieve 100% of glucan retention in DES-pretreated biomass solid, 100% of hemicellulose hydrolysis, and 50.6% of lignin extraction. The fractionation performance of alkaline and neutral DESs were comparatively inefficient. To optimize the DES performance, types of acid constituent hydrogen bond donor (HBD) in DES that promoted EFB fractionation and lignin extraction were next investigated based on the acid’s functional group and molar ratio. The results showed that the presence of hydroxyl group (-OH) and short alkyl chain (-CnH2n+1) in the acid HBD could enhance lignin extraction and biomass fractionation performance. As a result, choline chloride:lactic acid (CC-LA) 1:15 and choline chloride:formic acid (CC-FA) 1:2 achieved the highest lignin extraction yield at >60 wt% when compared with the other acidic DESs. The EFB solid fractionated by both acidic DES were enriched with >80 wt% of glucan content. The type of DES solvent applied in lignin extraction process significantly affect the isolated lignin’s composition, molecular structure, thermal properties and their compatible downstream conversion technologies. CC-LA DEEL would be more suitable for functional modification as shown through the higher amount of labile β-O-4 linkage (2.52 unit/Ar) and volatile product emission. CC-FA DEEL encompassed a highly condensed structure due to the abundant C-C linkages formed via the extensive hydrolysis of ether bond. A circular biorefinery process was then proposed, in which the process was initiated with DES pretreatment for biopolymer fractionation and followed by the conversion of DES-fractionated biopolymers into bio-based materials or chemicals. This study demonstrates a step-wise DES constituent selection process for lignocellulosic biomass pretreatment. The findings obtained is expected to aid in the selection of DES solvent for efficient biomass fractionation, thus providing an alternative solution to the lagging development of the lignocellulosic biomass conversion, such as oil palm empty fruit bunch into a variety of bio-based products
Rock mass slope stability analysis based on terrestrial LiDAR survey on selected limestone hills in Kinta Valley, Perak / Muhammad Afiq Ariff Mohd Hellmy
Get PDFThe use modern mapping technology is necessary in assessing slopes and cliffs, especially in tropical countries as it is mostly inaccessible and covered with thick vegetation which restricts the conventional data collection only at the base of the cliff. Overhanging and sub-vertical characteristics of limestone hills in Kinta Valley together with highly fractured and day-lighting joints increase the possibility of rock slope failure. The main objective of this research is to assess the stability and rock mass properties of the limestone hills in Kinta Valley based on the output provided by terrestrial LiDAR and scanline survey. Terrestrial laser scanning (TLS) helps engineers and geologist to collect a high numbers of discontinuity data where it is inaccessible for manual data measurement. A total number of about 14 cliffs on 4 limestone hills were assessed. Gunung Lang and Kek Lok Tong show major potential failure trending towards east, Gunung Lanno towards southwest, Kwan Yin Tong towards west, and Gunung Cheroh with three directions of failure which are pointed towards the south, southwest and southeast direction. The integration of LiDAR method with the manual compass clinometer has become a better approach to assess the stability of limestone hills and other rock slope in the possible future