Strategi penghujahan saintifik terhadap perubahan konseptual konsep asid dan bes

Alternative frameworks refer to students’ misconceptions which disrupt and hinder students learning process. These alternative frameworks are inconsistent with the concept used by scientists. Therefore, a conceptual change is needed to convert students’ alternative framework to scientific concept. Existing conceptual change models do not emphasize scientific argumentation and multiple representative levels to foster this conceptual change process. Thus, this study developed a conceptual change model based on scientific argumentation strategy. The study began with a quantitative method to obtain data on students' mastery of scientific argumentation. Subsequently, a qualitative method was implemented to acquire in-depth information to develop a conceptual change model. Instruments to gather data were Open-ended Scientific Argumentation Test 1 and 2, Student and Teacher Semi Structured Interviews and Observation Checklist of Teaching and Learning Processes. Respondents were 358 form four science students from secondary schools in Pasir Gudang, Johor. Respondents were divided into two groups comprising individuals or groups to answer the Open-ended Scientific Argumentation Test 1. Forty one students were purposely selected to undergo interviews and another 32 students with different mastery of scientific concepts from individual argumentation were also purposely selected to go through guided group argumentation. Besides that, observations of teaching and learning processes, and interviews of five chemistry teachers were conducted. Data were analyzed using constant comparative technique and triangulated to ensure validity and reliability. Results showed that students who were involved in group argumentations tended to construct more complex scientific arguments consisting of sub-microscopic and symbolic levels and had less alternative frameworks. Furthermore, these groups’ scientific argumentation scheme consisted of multiple representations with rebuttal element. Results also indicated that a majority of the students involved in guided group argumentation showed conceptual change. From the findings, a conceptual change model based on scientific argumentation strategy was developed to eliminate students’ alternative frameworks and foster construction of scientific concepts. The conceptual change model contributes to the development of a society instilled with scientific concepts

ANALYSIS OF TRUNK ROTATION PATTERNS WHEN SWINGING AT DIFFERENT SPEEDS: A PILOT STUDY

As the trunk plays a vital role during the golf full swing, it is important to understand how body movements affect the golf swing. The purpose of this study was to determine how golfers increase club head speed through trunk rotation. Trunk rotation patterns were captured by 3D motion capture system at 250 Hz. To investigate the effective factors of increasing club head speed, we compared two situations, swing at normal club head speed and at accelerated club head speed, via the trunk rotation angles at three dimensions through six temporary events. The results showed that subtle differences between normal club head speed and accelerated club head speed. To increase club head speed, golfers might optimize the separation between shoulder and pelvic in the early downswing

Conceptual changes in scientific argumentation through guided group settings

The main goal of scientific argumentation is to foster students’ understanding of scientific concepts (von Aufschnaiters et al., 2008; Nussbaum, 2011; Sadler, 2004; Zohar and Nemet, 2002) and to eliminate alternative frameworks (Cross et al., 2008). The involvement of students in argumentative activities also enhances their scientific reasoning skills (Osborne et al., 2004). In order to induce conceptual changes through collaboration, instructional intervention are usually conducted following the socio-cognitive conflict design (Amigues, 1988). This design is based on the idea whereby the pairing of students with different initial conceptions will lead to their cognitive conflict. As a result, they will then seek for equilibrium to accommodate their naive concepts as scientific concepts. According to Kendeou and Broek (2007), when students’ existing concepts are activated and integrated with a scientific explanation, this will lead to an imbalance. The identification of this imbalance will trigger deeper information processing that causes conceptual changes. Mason (1996) stressed that conceptual change is likely to occur when students are asked to clarify, explain, and defend their own ideas

Penghujahan saintifik pelajar melalui pembinaan hujah bertulis dalam pengajaran dan pembelajaran berintegrasikan penghujahan

Penghujahan saintifik merupakan matlamat utama pendidikan sains masa kini dan diberi penekanan utama memandangkan kebolehannya dalam memupuk pembinaan pengetahuan saintifik pelajar. Kajian ini bertujuan mengkaji penguasaan dan skema penghujahan saintifik pelajar dalam pembinaan hujah saintifik selepas tamat sesi pengajaran berintegrasikan penghujahan berdasarkan kerangka Berland dan McNeil. Seramai 176 pelajar tingkatan empat aliran sains dari lima buah sekolah menengah terlibat dalam kajian ini. Data kajian dikumpul dengan menggunakan instrumen Ujian Penghujahan Saintifik Terbuka (UPSB) dan Temubual Separa Berstruktur Pelajar (TSBP). Data daripada hujah bertulis pelajar dianalisis dengan menggunakan sistem perisian SPSS Version 19.0 serta teknik analisis kandungan bagi menghuraikan secara mendalam penguasaan dan skema penghujahan pelajar. Dapatan kajian menunjukkan terdapat perbezaan signifikan antara hujah saintifik dengan hujah tidak saintifik yang dibina oleh pelajar. Pelajar aliran sains berupaya membentuk hujah saintifik dengan konsep sains yang tepat. Walaubagaimana pun, kebanyakan hujah saintifik yang dibentuk adalah hujah mudah pada aras makroskopik. Ini menunjukkan pelajar mempunyai pengetahuan terhadap fenomena yang dikaji tetapi tidak berupaya memberikan hubungan antara ketiga-tiga aras perwakilan iaitu makroskopik, sub mikroskoipk dan persimbolan bagi konsep yang terlibat. Sementara itu, skema penghujahan saintifik yang kerap dijumpai dalam kalangan pelajar adalah skema mudah yang terdiri daripada elemen dakwaan, bukti dan alasan ringkas pada aras makroskopik serta kekurangan elemen penyangkal berkaitan hujah alternatif. Justeru, guru sains seharusnya merancang pengajaran supaya berpusatkan pelajar serta menekankan aktiviti-aktiviti yang berteraskan penghujahan saintifik. Pendedahan dan pengalaman kemahiran penghujahan saintifik yang diperolehi dapat meningkatkan penguasaan penghujahan saintifik pelajar sekaligus meningkatkan pemahaman pengetahuan kandungan sains pelajar

A simple potentiometric biosensor based on carboxylesterase for the analysis of aspartame

A potentiometric aspartame biosensor was fabricated by simply depositing the carboxylesterase (CES)-bonded poly(n-butyl acrylate-n-acryloxysuccimide) [CES-poly(nBA-NAS)] microspheres on a Ag/AgCl screen-printed pH selective electrode. The pH transducer was made from non-plasticized polyacrylate membrane containing a hydrogen ionophore and lipophilic salt. The immobilized CES enzyme catalyzed the enzymatic hydrolysis of aspartame to L-aspartic acid (L-Asp), L-phenylalanine and methanol. Potentiometric determination of aspartame concentration was performed by quantifying the hydrogen ion concentration produced from L-Asp. The potentiometric determination of aspartame exhibited good selectivity with near Nernstian response. The sensitivity of the biosensor was closed to the Nernstian value, i.e., 50-52 mV decade-1 with a dynamic linear response range from 10-5 to 10-2 M and detection limit approaching 10-6 M. The aspartame biosensor demonstrated good repeatability and reproducibility with relative standard deviation (RSD) of 1.9% and 1.6%, respectively (n=3). The potentiometric aspartame biosensor was demonstrated to be reliable for determining aspartame content in sweetener samples and was comparable to the conventional high-performance liquid chromatography (HPLC) method for aspartame analysis

Biosensor DNA voltametri berasaskan nanozarah emas bersalut elektrod bercetak skrin karbon untuk pengesanan DNA organisma terubah suai genetik (GMO)

Genosensor voltametri untuk pengesanan DNA organisma terubah suai genetik (GMO) telah dibangunkan berasaskan nanozarah emas (AuNPs) dan elektrod pes karbon bercetak skrin (SPE). AuNPs telah dipegunkan pada SPE melalui kaedah pertumbuhan perantara benih dan dicirikan dengan mikroskop elektron pengimbasan (SEM). 6-Mercapto-1- heksanol (MCH) telah digunakan untuk membentuk lapisan mono prob DNA rantai tunggal (ssDNA) pada SPE terubah suai AuNPs (AuNPs-SPE). Biosensor GMO telah dioptimumkan secara elektrokimia menggunakan oligonukleotida sintetik melalui teknik voltametri denyutan pembezaan (DPV). Biosensor GMO yang dioptimumkan kemudiannya digunakan untuk menganalisis sampel sebenar bagi pengesanan khusus urutan DNA dalam virus mozek kubis bunga, iaitu gen CaMV 35S. Isyarat penghibridan DNA dipantau berdasarkan arus puncak pengoksidaan penunjuk redoks asid monosulfonat antrakuinona (AQMS) semasa interkalasinya ke dalam dupleks DNA. Biosensor GMO memberi rangsangan secara linear kepada DNA terubah suai genetik (GM) antara 0.1 nM dan 300.0 nM dan had pengesanan diperoleh pada 0.06 nM. Sisihan piawai relatif (RSD) kebolehulangan biosensor GMO dianggarkan pada 6.7-7.8%. Biosensor GMO berasaskan AuNPs mempamerkan prestasi pengesanan DNA yang lebih baik daripada segi julat linear dinamik dan had pengesanan berbanding dengan biosensor GMO elektrokimia yang dilaporkan sebelum ini. Biosensor DNA elektrokimia ini menyediakan satu platform pengesanan pakai buang untuk aplikasi dalam ujian bahan GMO

A Biosensor for Genetic Modified Soybean DNA Determination via Adsorption of Anthraquinone‐2‐sulphonic Acid in Reduced Graphene Oxide

An electrochemical DNA biosensor for DNA determination of genetically modified (GM) soybean (CaMV 35S target genes) was developed utilizing a new detection concept based on the adsoption of anthraquinone‐2‐sulphonic acid (AQMS) on the reduced graphene oxide nano‐particles (rGO) during DNA hybridization events. The aminated DNA probe for CaMV 35S was immobilized onto poly(n‐butyl acrylate) film modified with succinimide functional groups [poly(nBA‐NAS)] via peptide covalent bond. Nanosheets of rGO were entrapped in the poly(nBA‐NAS) film to form a conducting [poly(nBA‐NAS)‐rGO] film of the DNA biosensor. Besides facilitating the electron transfer reactions, the rGO also functioned as an adsorbent for AQMS. The sensing mechanism of the proposed DNA biosensor involved measuring the oxidation current of the AQMS adsorbed on the electrode surface at −0.50 V using differential pulse voltammetry (DPV) before and after a DNA hybridization event. Under optimum conditions, the DNA biosensor demonstrated a linear proportionality between AQMS oxidation signal and logarithm cDNA concentration from 1.0×10−15 M to 1.0×10−8 M target DNA with a detection limit of 6.3×10−16 M. The electrochemical DNA biosensor possessed good selectivity and a shelf life of about 40 days with relative standard deviation of reproducibility obtained in the range of 3.7–4.6% (n=5). Evaluation of the DNA biosensor using GM soybean DNA extracts showed excellent recovery percentages of 97.2–104.0