In a simple and instant procedure for detecting fish freshness, a hydrogel and hydrophilic pectin matrix membrane was used successfully as an optical pH sensor by immobilizing the chromoionophore ETH 5294 (CI), which is very selective and sensitive for the membrane. The Pe/CI optical pH sensor exhibited excellent linearity between pH 5 and pH 9, with a sensor response time of 5 min and reproducibility of 1.49% relative standard deviation (RSD). The sensor showed response stability for 15 days and a response reduction of 8.6%. The sensor’s capability was demonstrated by the detection of fish freshness for 17 days at 4 °C.

A novel and simple optical biosensor to detect triglycerides (TGs) has been successfully constructed by using pectin hydrogel membrane as the indicator pH and chromoionophore ETH 5294 (CI), with lipase as the catalyst. The enzymatic working system against TGs releasing H+ ions will affect the color absorbance of CI. The characterization results show that a TG biosensor has the optimum condition and sensitivity at the phosphate buffer concentration of 50 mM, pH 7, and enzyme loading of 60 μg. The biosensor works at the tripalmitin (TP) concentration range of 100–400 mg/dL. With the sensitivity of 0.001 (∆A/(mg/dL)), the biosensor response reaches stability after five minutes, and the limit of detection (LOD) of the TG optical biosensor is 15 mg/dL. Relative standard deviation (RSD) in a reproducibility test was 2.5%, with a 15-day lifespan.

This study departs from the expectation that high or low student learning motivation are influenced by self-efficacy and family environment. The results of the study show that: 1) self-efficacy has a significant effect on learning motivation. 2) self-efficacy and parental support have a significant effect on learning motivation. This research is an associative descriptive study. The sample in this study is the business management students of class X and XI that are registered at Padang Private Vocational School. The findings from this study are expected to be a reference for teachers and other academic communities to be able to pay more attention to students in learning by giving attention to the family environment and paying attention to their learning attitudes and also help increase student motivation in learning so that maximum learning outcomes are obtained

Pectin from Arabica Gayo coffee pulp has been successfully isolated using citric acid as a solvent. The pectin extracted from the coffee pulp is determined by the extraction conditions. This study aims to produce pectin from dried coffee extract using citric acid using two factors, namely the difference factor of citric acid (1: 5 and 1: 20 b/v) and extraction time 75 and 150 minutes. The optimum ratio of Arabica Gayo coffee pulp with citric acid was 1:20 b/v with rendemen 7,8 % with 125 minute extraction time and at the temperature of 80 °C and pH 4. The methoxyl content of isolated pectin was 12.71 % and has been determined as high methoxyl pectin (HMP). The result of analysis with FTIR is known that the extract produced is pectin with comparison with pectin standard. The pectin has been used as a matrix membrane and showed its smooth surface gel form and smaller diameter from scanning electron microscopy (SEM).1

The tar resulted from pyrolysis of coconut shell is a waste. It is important to be clarified their chemical composition and physical properties in order to find out their feasibility as source of a fuel. This research was resulted two immiscible organic fractions, and these were further determined their physical properties such as water composition by using ASTM D-95 methods, ash composition (ASTM D-482), flash point C.O.C (ASTM D-92), kinematics of viscosity (ASTM D-445), and caloric valued using bomb calorimetric. In addition, tar composition was determined by gas chromatography-mass spectrometry (GCMS). The result provided oil which was categorized as light and heavy bio-oils. The light bio-oil has specific gravity 0.99, ash content 0.01%, kinematics viscosity 25.5 cSt, flash point <27 o C, pH 3 and heating value 10304 kcal/kg. On the other hand, heavy biooils gave specific gravity 1.13, ash 0.46%, kinematics viscosity 185 cSt, flash point 134 o C, pH 2.5 and heating value 6210 kcal/kg. Moreover, the light bio-oil contained 79 compounds which was composed of phenol 16.4%, hydrocarbon 12.4%, phenolic 27.6%, other oxygenated compounds 53.6%, and acetic acid 3%, meanwhile the heavy bio-oils contained of 18 compounds which was consisted of phenol 31.2%, lauric acid 6.0%, phenolic 27.6%, and other oxygenated compounds 35.3%, respectively. With this result, it was clarify that these bio-oils could not be used directly as a fuel for motor nor diesel machinery.

A new way to administer platelet-rich plasma (PRP) to improve its viability in more complex and chronic wound healing and soft/hard tissue regeneration in alveolar ridge preservation is demanded. In this study, PRP was encapsulated in chitosan to form a nanosphere with size below 100 nm with an idea to prolong PRP's growth factors release. Chitosan nanosphere was prepared by ionic gelation method, while PRP was encapsulated by inclusion method. Morphology analysis by transmission electron microscope (TEM) showed that PRP was encapsulated efficiently in the chitosan matrix, making a spherical shape with size of 30-80 nm. Particle size analysis by dynamic Light Scattering (DLS) method further showed that the average size of chitosan-PRP nanosphere was 51.27±33.75 nm, which is a good indication for biomaterials used in body. The stability of the nanoparticle colloid was confirmed with zeta potential score of 50.42 mV. 200 μl encapsulation of PRP in chitosan nanosphere had the highest encapsulation efficiency, that was further used in total protein release analysis in phosphate buffered saline (PBS) solution. It started with initial burst at 7 h, followed by steady release, then 'quasi-plateau' after 96 h (at around 60%), dominated by Korsmeyer-Peppas kinetics model and Fick's diffusion mechanism. Finally, the nanosphere showed an excellent antibacterial activity against S. mutans as shown from 90.63% bacteria inhibition during assay. The results showed that chitosan-PRP nanosphere could be used as a novel approach for complex/ chronic wound healing and soft/hard tissue regeneration following periodontitis treatment or tooth extraction that needs prolonged growth factor release.

The COD (Chemical Oxygen Demand) analysis method based on the Indonesian National Standard (SNI) is a revision of SNI 06-6989.2-2004, Water and wastewater - Part 2: Method of testing for chemical oxygen demand (COD) with closed reflux spectrophotometrically. This SNI uses references from international standard methods, namely Standard Methods for the Examination of Water and Wastewater, 21st Edition, editor of LS Clesceri, AE Greenberg, AD Eaton, APHA, AWWA and WEF, Washington DC, 2005, Methods 5220 D (Closed Reflux, Colorimetric Methods). The purpose of this study was to validate the total method for testing chemical oxygen demand (COD) in water and wastewater with the reduction of Cr2O7 2- spectrophotometrically in the range of COD values of 100 mg / L to 900 mg / L measurements were made at a wavelength of 600 nm. and COD values less than or equal to 90 mg / L measurements were made at a wavelength of 420 nm. The results showed that the method SNI 06-6898.2- 2009  has good validation results including the r results obtained from the calibration curve equation of 0.998, a precision of 1.82%, an accuracy of 98.25% and LOD and LOQ of 12.27 mg / L and 25, 61 mg / L.

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness. Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.