Quantitative structure-activity relationship for antimalarial activity of artemisinin

The increase in resistance to older drugs and the emergence of new types of infection have created an urgent need for discovery and development of new compounds with antimalarial activity. Quantitative-Structure Activity Relationship (QSAR) methodology has been performed to develop models that correlate antimalarial activity of artemisinin analogs and their molecular structures. In this study, the data set consisted of 197 compounds with their activities expressed as log RA (relative activity). These compounds were randomly divided into training set (n=157) and test set (n=40). The initial stage of the study was the generation of a series of descriptors from three-dimensional representations of the compounds in the data set. Several types of descriptors which include topological, connectivity indices, geometrical, physical properties and charge descriptors have been generated. The number of descriptors was then reduced to a set of relevant descriptors by performing a systematic variable selection procedure which includes zero test, pairwise correlation analysis and genetic algorithm (GA). Several models were developed using different combinations of modelling techniques such as multiple linear regression (MLR) and partial least square (PLS) regression. Statistical significance of the final model was characterized by correlation coefficient, r2 and root-mean-square error calibration, RMSEC. The results obtained were comparable to those from previous study on the same data set with r2 values greater than 0.8. Both internal and external validations were carried out to verify that the models have good stability, robustness and predictive ability. The cross-validated regression coefficient (r2 cv) and prediction regression coefficient (r2 test) for the external test set were consistently greater than 0.7. The QSAR models developed in this study should facilitate the search for new compounds with antimalarial activity

Chemometrics study and assessment of selected Indian dishes in Taman Universiti Teknologi Malaysia for sourcing essential mineral nutrients

Purpose of food is primarily to maintain life based on the inherent nutritive and nourishment properties of its content. This study is aimed at examining the mineral content of table ready dishes as remedy for a number of Mineral Deficiency Diseases (MDD). It is a more convenient alternative to conventional supplementation which is less affordable and sometimes harmful. Food samples were collected as served dishes from local restaurants around Taman Universiti Teknologi Malaysia. The dried samples were blended in electric blender made of plastic chamber and stainless steel blade. Optimum wet ashing procedure was adopted with control of heat and proportionate use of Nitric acid and Hydrogen Peroxide. The elements (Ca, Mg, K and Na) were obtained using Flame Atomic Absorption Spectrometry (FAAS). Phosphorus was determined using Inductively Coupled Plasma- Mass spectrometry (ICP-MS).The studied dishes revealed the presence of these elements but in varied quantities. Unsupervised techniques of the Principal Component Analysis (PCA) and Cluster Analysis (CA) were employed to distinguish patterns and groupings among the dishes. The PCA revealed a reduced dimension of the whole variables into two Principal Components responsible for 90% of the total variability. Both PCA scores and CA dendrogram show one large grouping and sets of some independent food samples. While Banana leaf rice and Roti canai stand out, the other interesting set consisting of Banana Leaf rice, Fish head curry and Nasi Beriani highly correlate positively with Ca, Na, P and K elements. Overall result shows that the Required Dietary Allowance (RDA) for the mineral elements can be met with careful choice of food, hence being, potential remedies for some MDDs

Classification of petroleum-based accelerants in fire debris using gas-chromatography mass spectrometry and chemometric technique

The classification of petroleum-based accelerants in fire debris samples have been studied using gas chromatography-mass spectrometry (GCMS) and chemometric technique. Samples were collected from carpets burnt with three different types of accelerants: gasoline, kerosene and diesel. Some of the charred carpets were left for several days to study effect weathering on the classification. Total ion chromatograms obtained for each sample were subjected to principal component analysis (PCA). The chromatograms identified the hydrocarbons present in the samples while PCA perform the classification based on the peak area of each component. This study showed that, by using PCA, we were able to cluster the samples according to type of accelerants used even though some of the samples were collected several days after the incident

Pendekatan inkuiri dan teknik penyoalan guru: isu dan perlaksanaannya dalam proses pengajaran dan pembelajaran kimia

Peranan guru dalam sistem pendidikan khususnya di Malaysia merupakan tunjang pelaksana setiap dasar yang dirancang oleh Kementerian Pendidikan Malaysia (KPM). Guru merupakan jentera penggerak bagi setiap dasar yang dirancang oleh KPM. Kini tugas guru semakin mencabar, guru bukan sahaja menjadi penyampai ilmu pengetahuan dan kemahiran kepada pelajar malahan bertanggungjawab untuk menyemai minat, memperkembangkan bakat dan kebolehan pelajar. Proses pembelajaran yang berkesan akan mengasah pemikiran analitikal, kritikal dan kreatif bagi membentuk individu yang dapat menyesuaikan diri dengan perubahan persekitaran yang semakin drastik selaras dengan hala tuju sistem pendidikan negara. Menyedari hakikat ini, kerajaan Malaysia telah memberi fokus untuk memacukan peningkatan profesionalisme guru dalam gelombang pertama Pelan Pembangunan Pendidikan Malaysia, 2013-2025 (Saedah Siraj & Mohammed Sani Ibrahim, 2012)

Learning chemical reaction via augmented reality

The possibility of using Augmented Reality (AR) program as supplementary material in learning chemistry is evaluated in this paper. Chemistry is regarded as difficult to learn due to abstract nature of the subject. The content learning of the subject comprises multiple levels of representation, which challenge the conceptual understanding and problem solving of a student. This study is trying to identify the difficulty of learning chemistry particularly in acids and bases topic in term of conceptual understanding and algorithmic problem solving. Students are known to consistently make mistake writing the symbol of chemical formulas and also confused between the use of subscript and coefficient of a chemical formula. These eventually lead to wrong stoichiometry in balancing the chemical equation. The mistakes snowball into bigger problems when students are not able to understand the chemical equation in term of the algorithm and also conceptual. In order to the address the issues, students’ understanding regarding the chemical reaction of acids and bases should be investigated to elucidate student alternative conception if any in order to suggest suitable features for learning acids and bases chemical reaction using the AR program. As the issue is considered prevalent, the need of effective and promising solution is critical, thus AR should be evaluated as a supplementary teaching aid. AR helps students in visualizing the microscopic part of the reaction hence should promote correct understanding of the chemical reaction. The technology is considered recent and the use in chemistry field has been reported. However in chemical reaction learning, data supporting the effectiveness of the AR program is still insufficient. The effectiveness of the program towards students’ algorithmic problems solving and conceptual understanding in the acids and bases topic can be investigated. The results from the study should suggest the significance of the AR program in learning chemical reaction and equation in chemistry

Aktiviti penilaian dalam makmal menggunakan peta konsep dalam menjana kemahiran berfikir aras tinggi: suatu kerangka teori

Perubahan dunia yang pesat telah menuntut kepada transformasi pendidikan, bukan sahaja dari aspek kurikulum dan pedagogi, malah komponen pentaksiran dan penilaian juga perlu dititikberatkan. Matlamat pendidikan abad ke21 adalah untuk menghasilkan pelajar yang mempunyai kefahaman mendalam terhadap sesuatu ilmu pengetahuan serta mempunyai kemahiran berfikir aras tinggi yang diharap dapat melahirkan tenaga kerja yang cemerlang. Aktiviti makmal penting dalam mempelajari ilmu Kimia yang terdiri daripada pelbagai konsep abstrak. Melalui aktiviti ini, pelajar seharusnya lebih memahami dan menguasai sesuatu topik pembelajaran seterusnya membantu kepada rangsangan kemahiran berfikir aras tinggi. Bagi mengukur hasil pembelajaran aktiviti tersebut, aktiviti penilaian merupakan aspek penting yang perlu ditekankan. Peta konsep merupakan salah satu alat penilaian pembelajaran yang dikatakan dapat membantu pelajar menvisualkan konsepkonsep yang telah difahami serta menjadi platform kepada rangsangan KBAT. Maka, suatu kerangka teori diperlukan untuk mendasari kajian ini. Pada asasnya, teori konstruktivisme merupakan tunjang kepada aktiviti penilaian dalam makmal yang diharapkan dapat meningkatkan kefahaman konseptual yang mendalam dan diperlukan dalam menjana kepada peningkatan kemahiran berfikir aras tinggi pelajar

Concept map as an alternative assessment in laboratory activities

The rapid development of the world's technological advances, economy competition, scientific innovation generally have claim to the transformation of the educational system as a whole (Koh, Tan, Ng, 2012). The transformation done in science, math, technology and engineering in the 21st century is emphasized to the formation of students who can demonstrate higher thinking skills with confidence, such as critical thinking and creative, innovative thinking and problem solving (Evren, Bati & Yilmaz, 2012). This is of concern not only to provide a workforce that is ready to compete at the global level, but more importantly for the development of self as individuals more successful (Ministry of education, 2012)

Potential role of Nigella sativa (NS) in abating oxidative stressi-induced toxicity in rats: a possible protection mechanism

The seeds of Nigella sativa (NS), have been widely used in herbal medicines worldwide. It has been shown to possess prophylactic effects against oxidative stress. However, there is a paucity of information regarding the protective role of NS against oxidative stress, in the absence of toxic agents. The aim of the study was to elucidate the anti-oxidative stress pharmacodynamics of NS. Eighteen, 12-week-old Sprague-Dawley rats, weighing about 300 ± 25 gm were divided equally into six groups. Four of the groups were supplemented with NS at 100 mg/kg b.w/day orally (P.O.) and labeled as, 1st, 3rd, 5th and 6th day groups. The PCx (positive control) group was given distilled water orally, and the NCx (negative control) group rats were provided with food and water ad libitum. Blood samples were collected, and rats were sacrificed on days 1, 3, 5 and 6 (2h) post-treatment. The blood was used for oxidative stress enzymes analysis (SOD, GSH-Px and MDA), liver (ALT) and kidney (creatinine) function assay, and the liver, kidney and spleen were dissected for histology. The results revealed that NS exhibited an anti-oxidative stress effect in the liver and kidneys as indicated by the low levels of ALT and creatinine. In response to antioxidant enzymes, especially that of the 3rd-day treatment group, an increase in SOD and GSH-Px indirectly caused an alleviation of oxidative stress, leading to a much lower level of MDA. It was concluded that treatment with NS at 100 mg/kg b.w/per day for three consecutive days, demonstrated the highest efficacy in abating oxidative stress in rats

On properties of modified degree six chordal rings network

Chordal rings are circulant graphs and have deserved significant attention in the last decade. Chordal rings were used to build interconnection networks for distributed and parallel systems. There are many of publications analyzing their networks properties. In this paper, we present the main properties of the latest method of chordal rings called Modified Chordal Rings Degree Six (CHRm6). The properties are connectivity, Hamiltonian cycle and asymmetry. We prove some lemmas and theorems for every property. All of these properties are useful for further works especially in developing a routing scheme

Analysis of modified degree six chordal rings and traditional chordal rings degree six interconnection network

Chordal rings are attractive network interconnection due to their short diameters especially when the degree was increased. Chordal rings were related to find the shortest path in a ring structured. This paper presents an analysis of modified degree six chordal rings (CHRm6) and chordal rings degree six (CR6) or commonly known as traditional chordal rings degree six (CR6). This analysis includes the structures, tree visualization, paths, formulations and geometrical representation. The comparison of diameters was made between theoretical and ideal graphs for these two methods. We tested and compared for a large number of nodes. CHRm6 gives shortest diameters for even and odd source node