bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antioxidant Potential of Virgin Coconut Oil Reduced Creatine Kinase Levels in Non-Athlete Students receiving Submaximal Physical Exercise
Authors: Sinaga RN , Sinaga FA , Elvana A , Manalu N 
Published: March 2021

Abstract
Damage to the muscle cell acute and chronic can be caused by strenuous physical exercise. Oxidative stress that occurs during strenuous exercise contributes to muscle cell damage. One indicator of muscle cell damage is creatine kinase in the blood serum. Natural antioxidant can be given to counteract the free radicals and reduce oxidative stress. Virgin coconut oil is a natural plant that has potential as an antioxidant. The purpose of this study was to determine the effect of virgin coconut oil on muscle damage by looking at the creatine kinase activity during submaximal exercise in non-athlete students. This is an experimental study with a randomized control group pretest-posttest design. The sample in this study were ten people who were divided into two groups. The control group was given a placebo while the experimental group was given virgin coconut oil at a dose of 15 ml. All groups received submaximal physical exercise with an intensity of 80-90%, a frequency of 3 times a week for one month. Creatine kinase was measured before and after treatment. The creatine kinase activity in the control group increased significantly while the experimental group decreased insignificantly. Virgin coconut oil in this study significantly reduced creatine kinase activity. The antioxidant potential of virgin coconut oil can repair muscle damage in non-athlete students receiving submaximal physical exercise.
Synthesis and Characterization of Activated Carbon from Oil Palm Empty Bunches
Authors: Jasmidi  , Sari S A , Selly R , Rahmah S , Nasution H I , Zubir M , Banjarnahor L R , Efendi Y D 
Published: March 2021

AbstractIn this study, activated carbon was prepared from empty oil palm bunches obtained from Padang Bulan, Medan, North Sumatra. The empty oil palm bunches are cleaned, then mashed to obtain a particle size of 200 mesh which is then referred to as the oil palm empty bunches bio-sorbent. This bio-sorbent is then washed with water to remove impurities that may come from fertilizers or insecticides during processing in oil palm plantations such as K, Ca, Mg, Si and P, which are visible from the EDX analysis results of bio-sorbent before washed. From the EDX data after washing, the was observed if there are no peaks of these impurity elements. From the XRD pattern it can also be seen that there are some peaks missing after washing if compared to XRD bio-sorbents. Activated carbon then prepared by heating the bio-sorbent at 500 °C for 1 minute, and the XRD results show an amorphous structure as a characteristic of the formation of activated carbon. SEM images can also be observed that the difference in the surface of the activated carbon is smoother than the surface of the bio-sorbent, besides the activated carbon looks more homogeneous.
Students’ Interest in Concept-Based Learning and Drill Method Learning and Their Concept Mastery Achievement in Biology Instructional Methodology Course
Authors: Muttaqiin Arief , Lufri Lufri , Yogica Relsas , Fitri Rahmadhani 
Published: March 2021

Abstract
This research is part of the research on the development of the concept-based learning model and drill method. In this article, we will describe the relationship between students ‘interest in concept-based learning model and drill method with students’ mastery of concepts in the Biology Instructional Methodology course. A total of 37 samples were students majoring in Biology Education, Padang State University. Data were collected using instruments in the form of psychological questionnaires about student interests and instruments in the form of descriptive questions. Based on the analysed data, it is known that the variable student interest in the concept-based learning model and drill method has a positive relationship with student mastery of concepts, which is r= 0.169 and sig. 0.316 using the Spearman’s Rank Correlation Test. This shows that the higher the student’s interest in learning using the concept-based learning model and drill method, the higher the students’ mastery of concepts in the Biology Instructional Method course.
Experimental 1H and 13C Solid-State NMR Signal Assignment of Paramagnetic Copper (II) 2-Pyrazine-Carboxylate Complex using Density Functional Theory Calculations
Authors: Patil Bhargava Hanumanta , Peraje Pampa , Naik Dinesh , Rajaramakrishna R , Dittmer Jens , Kumara Swamy Shashi Kumar 
Published: March 2021

Abstract
We have acquired 1H and 13C solid-state NMR (ssNMR) spectra of the paramagnetic Cu(II)-2-pyrazine-carboxylate (Cu-Py) complex and assigned paramagnetic 1H/13C signals using density functional theory (DFT) calculations. The unpaired electron in Cu(II) ionexacerbates the 1H and 13C chemical shifts in the Cu-Py complex through hyperfine interactions, making the conventional NMR signal assignment non-feasible. Further, the nuclear fast relaxation in paramagnetic metal-organic system hampers application of routine ssNMR techniques for signal acquisition. In our work we have employed simple DEPTH experiment at 50 kHz magic angle spinning (MAS) for acquiring 1H and 13C 1D ssNMR spectra of the paramagnetic Cu(II)-2-pyrazine-carboxylate (Cu-Py) complex. The paramagnetic augmented (diamagnetic chemical shift + paramagnetic shift) 1D 1H and 13C ssNMR signals (shifts) from Cu-Py complex have major contribution from Fermi contact interaction due to proximity of the organic arm to Cu2+ ion (Cu2+-C/H atoms 0-5 Å). The unpaired electron spin density distributed over the pyrazine-carboxylate organic arm is crucial in understanding Fermi contact shifts and hence accounts for 1H and 13C ssNMR signal assignment. The theoretical Fermi contact shifts together with diamagnetic shifts, calculated using density functional theory (DFT) at B3LYP level with basis sets viz. 6-311G, 6-311G+(D) and 6-311G++(D), were compared with the experimental shifts to facilitate the process of signal assignment. Vibrational analysis of Cu-Py complex was performed at B3LYP level of theory with various basis sets in comparison with experimental IR data. This further assisted in double validation of DFT optimized Cu-Py structure used here for extracting Fermi contact shifts. Furthermore molecular orbital analysis on the DFT optimized Cu-Py structure articulates the spin density distribution mechanism, thereby stipulating the location of the unpaired electron in the Cu(II) dx
2
-y
2 orbital in Paramagnetic Cu-Py complex.
Student Perceptions of Augmented Reality (AR) Media in Calculus Courses
Authors: Elfitra  , Mansyur A , Taufik M.I 
Published: March 2021

Abstract
Learning media plays an important role in the learning process. The development of technology and science also has an impact on the development of learning media. One of the learning media developments that are currently still new is learning media using Augmented Reality. Augmented Reality is an application that combines the real world with the virtual world in two-dimensional or three-dimensional form which is projected in the real environment at the same time. This research is a descriptive study conducted by using a questionnaire to students. The descriptive analysis in this study examines students’ perceptions of Augmented Reality media in Calculus Learning. Augmented Reality media response in terms of aspects of Media Design, Material Content and Benefits. The results obtained by an average Augmented Reality media design is 85.7 with a decent category, the average Augmented Reality Media Material Content is 83 with a decent category and the average aspect of benefits is 83.5 with a decent category. Based on the rearata, the score for the observation aspect of AR learning media is 84.07 with a decent category. However, many improvements are needed, including a reduction in application capacity and 3-dimensional display.
Affective Assessment Tools Development in Biology Subjects for X Grade in State High School
Authors: Pratama D J , Edi S , Syarifuddin  
Published: March 2021

Abstract
This study aims to develop affective assessment tools in high school grade X Biology subject. The instrument developed will be tested for validity, reliability and practicality. The research was conducted at SMAN 1 and SMAN 2 Tanjungbalai. The development of affective domain assessment instruments is carried out using the 4-D model which is carried out in stages. The stage consists of Define, Design, Development and Dissemination. The result of research consisted of valid, practical and reliable affective assessment instruments that can be used to conduct affective assessments in schools. Validation value of the affective domain assessment instrument is 90.5%, categorized as good and worthy of use.
The Development of Science Student Worksheet for Elementary Student Grade IV Based on Scientific
Authors: Lubis S J , Harahap F , Saragi D 
Published: March 2021

Abstract
The research is a type of research and development that aims to determine the validity and response of students and teachers to the science student worksheet constructed on the science approach. Science student worksheet development applies the 4-D model development procedure consist of 4 stages specifically: define, design, develop, and disseminate. The subjects of this research were IVA& IVB class at SD IT Deli Insani consist of 55 students. The data collection instruments were in the formula of assessment sheets for material authorities, learning design authorities, layout, linguists, and the response questionnaire sheets for students and teachers. This development research produces the material, learning design, layout, and language with an average percentage level 93,5% which is characterized as legitimate and suitable for usage, and get a decent response from the students reached 96,2% and with decent criteria and response teacher getting 94,9% with decent criteria. Based on expert validation, the developed student worksheets are declared suitable for use by students, especially class four. Based on the responses of students and teachers, the students’ worksheets developed received a good response so that it was stated that the worksheets were easy to understand and interesting to learn. The benefits of developing science student worksheets based on the developed scientific approach are expected to be reference materials for educators in developing student worksheets according to the needs of students and in accordance with the demands of the 2013 curriculum.
Stability Analysis of the Corona Virus (Covid-19) Dynamics SEIR Model in Indonesia
Authors: Sinaga L P , Nasution H , Kartika D 
Published: March 2021

Abstract
Covid-19 is a type of virus that infects the respiratory tract or is also known as severe acute respiratory syndrome Corona virus-2 (SARS-CoV-2). Researchers through this study were trying to build a mathematical model of the spread of the Covid-19 virus and analyzed the stability of its critical points. This virus dynamic model was built based on the interaction between the suspect group with the exposed group and the interaction with the infected group. The virus spread model in this study consists of two critical points, namely a disease-free critical point and a disease endemic critical point. The two critical points will be stable if they meet the requirements for certain parameter values. Numerical simulations of virus dynamics in Indonesia were carried out using data on the number of susceptible people, the number under monitoring, the number of the infected, the number of cures and the number of deaths due to the virus. These data were obtained from the Ministry of Health of the Republic of Indonesia. Based on the data obtained, it was found that the simulation model of stability reached a critical point in a very long time. Therefore, treatment or vaccines are needed as a step to reduce the dynamics of Covid-19.
The Effect of Teams Games Tournament (TGT) Method on Outcomes Learning and Conceptual Knowledge in Physics Science
Authors: Panggabean Jonny Haratua , Defi Siregar Masda Sri , Rajagukguk Juniastel 
Published: March 2021

Abstract
This study aims to determine the effect of the TGT (Teams Games Tournaments) cooperative learning model on students’ conceptual knowledge on momentum and impulse material in grade X 7th state Senior High School (SMA) in Medan City. The research type is a quasi-experiment with a two-group pretest-posttest design. The instrument used in this study was a test of students’ conceptual knowledge in the form of multiple choices and an assessment sheet to measure student skills and student activities. After the learning was given, the two classes carried out a post-test. The experimental class obtained an average value of 83.19 and for the control class, an average value of 64.58 was obtained. And student learning activities in the cooperative learning process type TGT (Teams Games Tournaments) in three meetings experienced an increase with an average value of 72.4 (active) meeting I, 77.22 (active) meeting II, 82, 4 (active). Based on the test results, it was found that the cooperative learning model type teams games tournament had a significant effect on students’ conceptual knowledge on momentum and impulse material in grade X 7th state SMA in Medan City.
The Effect of Spin Coating Speed on Structural and Optical Properties of ZnO and ZnO/Dye Thin Films Synthesized by Sol-Gel Spin Coating Method
Authors: Motlan  , Siregar Nurdin , Panggabean Jonny Haratua 
Published: March 2021

Abstract
The ZnO thin films were successfully synthesized using sol-gel spin coating method. The surface other ZnO thin film then were coated with natural dye. Materials used were zinc acetate dehydrate, isopropanol, Diethanolamine and purple heart flower consecutively as based materials, solution, stabilizer, and dye. The ZnO thin films were grown glass by dropping Sol-gel on a surface of FTO glass with spin coating speed variation of 2000, 3000, 4000, and 6000 rpm. The ZnO thin films then successively pre-heated and pot-heated at 250°C and 550°C for 5 hours and holding time of 30 minutes. The source of the dye is boat lily flower was cut into small pieces and put into beaker glass. The sample then crushed with mortar and then milling until it becomes soft. Further, the extract was obtained by immersing it in aquadest, acetate acid, and ethanol with maceration technique. The ZnO thin films then immersed in an extract of dye solution for 24 hours to obtain ZnO/dye thin film. The XRD analysis shows that ZnO thin film size of within 26.5 – 36.9 nm. The optical properties of the ZnO and ZnO/Dye thin films were characterized using UV-Vis spectrometer. The UV-Vis spectrometer results show that there are variations of the ZnO thin film transmission as a result of spin coating speed of the Sol-gel spin coating method. The transmission of ZnO/dye thin films is higher than ZnO thin film and the absorbance of ZnO is higher than ZnO/dye thin films. The band gaps of the ZnO and ZnO/dye thin film were consecutively ranged 3.27 – 3.34 eV and 3.02 – 3.21 eV.
Molecular Docking of Quinine Derivative as Inhibitor in Sars-Cov-2
Authors: Roza Destria , Selly Rini , Munsirwan Rudi , Fadhilah Gianna 
Published: March 2021

Abstract
The discovery of various of new medicinal compounds from various research clarifies the important role of computational studies as the initial basis for finding sources of medicinal raw materials both from natural and synthetic. SARS-coronavirus 2 (SARS-CoV-2) or COVID-19 is the virus which is responsible for the outbreak that affects almost the entire world began in early 2020. This study aim is to determine the interaction between SARS-CoV-2 and quinine derivative compounds by utilizing and developing quinine plants as medicinal ingredients, especially Corona antivirus. The research was conducted in silico with the molecular docking method. The docking software used in this research is AutodockVina. The results showed that from the 10 tested compounds against SARS-CoV-2 virus cells, all of ithas the ability as an antivirus with the binding affinity of around -6 kcal / mol. The native ligands have the best binding affinity among the tested compounds which is around -7.9 kcal / mol. This is also supported by the number of hydrogen bondings and bond lengths as well.
Enhancing Students Multivariable Calculus Learning Through Online Formative Feedback
Authors: Mukhtar  , Mulyono  , Firdaus M 
Published: March 2021

Abstract
Feedback is a major component of formative assessment and thus can be said to have a high influence on student learning experiences. It is used to inform students of their strengths, weaknesses, and strategies so that the gap between their current knowledge and understanding and the desired standard of achievement can be narrowed. However, research shows that students are less encouraged to engage in the feedback process mainly because of their difficulty in relating to and reflecting on feedback comments. In this paper, we look at how to support the provision of formative feedback through e-learning tools. Our aim is to increase the acceptance of feedback and to reinforce the quality of feedback through the way the feedback is communicated to students. This study describes how communication activities promote deep learning.
Effect of the Vaccine on the Dynamics of Speread of Tuberculosis SIR Models
Authors: Nasution Hamidah , Sitompul Pardomuan , Sinaga Lasker P 
Published: March 2021

Abstract
Tuberculosis (TB) is an infectious disease that is very dangerous and can cause death and Tuberculosis (TB) is an infectious disease that causes the most deaths or is called the world’s biggest killer among infectious diseases, claiming more than 4000 lives every day. The unprecedented Corona Virus pandemic has a serious impact on people with pre-existing health conditions such as Tuberculosis. Tuberculosis is not caused by heredity and Tuberculosis is curable. Treatment of TB disease is time-consuming and costly. Therefore the term prevention is better than cure very precisely for Tuberculosis. One of the efforts made by the government is to provide vaccines. This study uses the SIR (susceptible, infected, and recovered) model by considering the effect of vaccines. Also, this study adopts the application of the Optimum Control theory which aims to provide control over the parameters that affect the spread of Tuberculosis. The purpose of this study is not only to show the dynamics of the spread of tuberculosis but also to see to what extent the effect of vaccines reduces the spread of tuberculosis. And how does the optimal control theory influence the spread of tuberculosis?This research is proposed to estimate the basic reproduction number (R0) from the dynamics of the Tuberculosis epidemic. The basic reproductive number ((R0) is often used as a threshold parameter to determine the boundary betweenextinction and endemic. If R0<1 indicates the dengue virus will become extinct and if R0> 1 shows the Tuberculosis is endemic. By considering vaccines identified a slowing of the spread of tuberculosis.
Worksheet to Built Critical Thinking Skills for Prevalence Covid-19 in Indonesia on Limited Time: Curve Matching Modelling
Authors: Bunawan Wawan , Sabani  , Lubis Rajo Hasim 
Published: March 2021

Abstract
Data on the spread of covid 19 in Indonesia is usually displayed in the form of a bar chart and a graph of the function of the number of people versus time for cases of increase, death and recovery. Display data in the form of graphs and diagrams is quite adequate for use in television news shows or breaking news. The Covid 19 case can be used as a source of authentic learning data in the Data Processing Workshop course investigation. Curve matching based data modelling can be developed in the form of scientific worksheets. The challenge of developing worksheets is at what stages must be done in order for the mathematical model to match the distribution of the data. The development of worksheets has met the academic requirements in terms of pedagogy and knowledge content. The validity and reliability of the worksheets have met the requirements according to the validator’s decision and evidence of empirical data analysis. Worksheets are developed based on excel, SPSS and Matlab with studies based on critical thinking skills. The scientific worksheets can improve critical thinking skills needed in the 21st century with several relevant indicators. The limitation of this study is that the prediction formula produced still does not meet the real data that occurs for cases of infection, recovery and death for a long time interval. The original research contained in the learning source data is authentic and continues to move during the pandemic. data is inputted into scientific worksheets that apply critical thinking skills in excel, spss and matlab presentation.
Best Medium for Production and the Activity of Biosurfactant from Local Strain of Pseudomonas
Authors: Priyani Nunuk , Munir Erman 
Published: March 2021

Abstract
A local strain of Pseudomonas has been isolated from Belawan, a big port in Medan, North Sumatera. This isolate was already tested on its ability to break down carbofuran, an active compound of widely used pesticide. The ability of bacteria to degrade carbofuran is closely related to the ability of bacteria to secrete biosurfactant. This compound promotes bacteria on carbofuran metabolism. This study aimed to find out the best medium for the local strain of Pseudomonas to produce biosurfactant and to characterize the compound. The isolate was cultured in several media with different combination of three different carbon sources which are glycerol, glucose, and olive oil; two types of nitrogen sources: sodium nitrate and ammonium sulfate at C/N ratio 20 and 60, two different time of incubation, 24 and 72 hours. The parameters observed were the bacterial growth, the concentration and the activities of biosurfactant. The results showed that during 24 hours of incubation the best medium for the production of biosurfactant was the combination of glucose and ammonium sulfate with C/N ratio was 60. The bacterial population was 2.230 at OD 621 nm, the highest biosurfactant activity, the Index of emulsion was 0.42 and the surface tension was 36.3 mN/m and the concentration of biosurfactant was 75.530 g/L. Meanwhile during 72 hours of incubation the best medium was shown by the combination of glucose and ammonium sulfate with C/N ratio was 20. The bacterial population was 2.252 at OD 621 nm, the Index of emulsion was 0.25 and surface tension was 30.0 mN/m and the biosurfactant concentration was 76.494 g/L.
Geothermal Fluid Identification at Geothermal Area Sorik Marapi using 2d Resistivity Imaging
Authors: Kadri Muhamad , Nordiana M.M. 
Published: March 2021

Abstract
This research is done to determine the geothermal fluid flows by using 2D resistivity imaging and to identify the stones that compile the mineral by using XRD at geothermal Area Sorik Marapi, North Sumatera Province. The area is located at 99°32’.050” E- 0°41’193’ N to 99°32.861” E- 0°41’214’N. The results from XRD by using difractometer Jeol-350 Shimadzu 6100 Show that the intensity from x ray difraction has the geothermal fluid spreads laterally to the geothermal manifestation. Four lines were surveyed by using 2d resistivity imaging for geothermal delineation purpose. The 2d resistivity imaging survey site shows the existence of geothermal fluid flows. The maximum depth of investigations for the surveys is 31,3 meters and 155 m of length of each line. The array used in this study areWennerSchlumberger. In general the results show that all the subsurface is made up of limestone (resistivity value of less 100 ohm-m) and clay with resistivity also less than 100 ohm-m in all the sections. XRD survey shows the mean mineral that compile the get othermal stones at Sorik Marapi are Quartz (O2Si) and magnesium (Mg). This mineral is the mean mineral that compile the clay.