bluuebunny/crossref_metadata_2025 huggingface dataset:
Descriptive statistics analysis of the variable in the data of toothbrushing simulator system modelling
Authors: Salleh Salihatun Md , Mansor Mohamad Norani , Hassan Hadirah , Mohd Yusoff Ainul Husna , Md Zin Badrul Aisham , Yahya Musli Nizam , Wijianto S. T.
Published: July 2020

The controller of a system can be designed by constructing the model from the known the input and output. Modelling the dynamic of the system can help to visualize the real behavior of the system to develop the suitable controller parameter. The measured data from the real system need to be analyzed statistically to support that the current system needs a controller to improve the system performance. This study analyzed the normality and linearity of the variables in the research data of Toothbrushing Simulator System Modelling which are Speed (RPM) as the output(Y) and Voltage (V) as the input (X). There were five different data sets with 1000 observations respectively. All the data had been analyzed by using IBM SPSS Statistics 23 in which it will be explained by graphical method of histogram, scatter plot and descriptive measures of coefficient f determination between variables. The results for this study turn out that all the data sets were not normally distributed and not linear. Hence, the result from this statistical analysis has proven that the controller development is very crucial for the toothbrushing simulator system to improvise the system performance.
Isolation, Identification, and Inhibition of Saponin Isolates from Pineapple (Ananas comosus L.) and Candlenut (Aleurites moluccanus L.) against Xanthine Oxidase by In Vitro Assay
Authors: Amalia Mimma , Alvionita Mieke , Subandi  , Susanti Evi , Nugraheni Dian
Published: July 2020

The exploration of gout treatment agent based on the natural product gains high attention in recent years. Although some current drugs effectively treat gout, fewer unbeneficial effects cannot be avoided. Thus, searching for new alternatives with fewer side effects is needed. This present work was aimed at investigating the potency of saponins in pineapple (Ananas comosus L.) and candlenut (Aleurites moluccanus L.) extract as an inhibitor of xanthine oxidase, an enzyme that responsible for gout disease, by in vitro study. The stage of this work was divided into six stages, including (1) sample preparation, (2) extraction of saponins using 70% ethanol, (3) isolation of saponins by thin-layer chromatography, (4) phytochemical test of saponins, (5) inhibitory activity testing of saponins using in vitro analysis, and (6) determination the types of saponins by UV-Vis, FT-IR and LC-MS/MS spectroscopy. The result from the preparative TLC of pineapple extract, there were three spots with Rf value of 0.95 (pi1), 0.65 (pi2), and 0.38 (pi3), while from candlenut extract there were two saponin isolates with Rf value of 0.95 (ci1) and 0.79 (ci2). The inhibition activity of each isolate against xanthine oxidase was 103.41% (pi1), 269.73% (pi2), 84.16% (pi3), 222.90% (ci1), and 157.05% (ci2) relative to Allopurinol 100 ppm. Based on spectroscopic analysis results, isolate with the greatest inhibition activity was likely a diosgenin type (C27H42O3) of saponin.
Preliminary Phytochemical Screening and Fluorescence Characterization of Several Medicinal Plants Extract from East Java Indonesia
Authors: Fardiyah Q , Suprapto  , Kurniawan F , Ersam T , Slamet A , Suyanta
Published: July 2020

The preliminary phytochemical screening and fluorescence characterization of several medicinal plant extracts from East Java Indonesia have been carried out. Some medicinal plants used in this study are Annona muricata, Strobilanthes crispus, Piper ornatum and Andrographis paniculata. The objective of this research is to find out the result of phytochemical screening and characterization of several medicine plants by fluorescence spectroscopy. The plant part in the form of leaves is extracted using maceration method. The extraction process was carried out for 3 days with ethanol solvent in room temperature. The result of preliminary phytochemical screening showed the existence of secondary metabolite compounds in several medicinal plant extracts, among others, alkaloid, saponin, terpenoid, steroid, tannin and flavonoid. The fluorescence characterization spectra obtained shows that several medicinal plant extracts have optimum absorption at wavelength of excitation of 323 – 342 nm and wavelength of emission of 662 – 685 nm.
The Reduction of Cadmium Concentration by Oscillatoria Microalgae in a Culture Media
Authors: Hentiana  , Setiawan Doni , Mohadi Risfidian , Hermansyah  , Zulkifli Hilda
Published: July 2020

Microalgae has functional group such as carboxylic (-COOH) and hydroxyl (-OH) which play an important role as adsorbent of heavy metal. Reduction of cadmium concentration by Oscillatoria microalgae in a culture medium has been carried out. This research aimed to study the ability of Oscillatoria microalgae as a biological adsorbent agent of cadmium heavy metal using BG-11 media. There were four treatments culture media with six repetitions consisting of P0 = 100 mL medium + 10,000 individual Oscillatoria; P1 = 1 mg/L Cd(II) + 100 mL medium + 10,000 individual Oscillatoria; P2 = 3 mg/L Cd(II) + 100 mL medium + 10,000 individual Oscillatoria; and P3 = 5 mg/L Cd(II) + 100 mL medium + 10,000 individual Oscillatoria. The result has shown the increasing of Oscillatoria in BG-11 culture media starting from day 4 to day 7 day was around 1208-1599 ind/L/day. P3 treatment which consist of 1 mg/L show the highest reduction of cadmium absorption with percentage of 24.05%, compared to the others.
Thiocyanate Doping in Gel-Growth Cobalt Oxalate Crystals
Authors: Khunur Mohammad Misbah , Wahyuni Dini Tri , Kurniawan Gigih Wahyu , Prananto Yuniar Ponco
Published: July 2020

The presence of other anions, as impurities and/or doping agents, may alter crystallization and the properties of the crystal. The objective of this research is to examine the effect of thiocyanate doping in the synthesis of cobalt oxalate crystals grown in silica gel. The synthesis was conducted at room temperature for 12 weeks in a U-tube glass filled with silica gel. The gel was prepared from Na2SiO3 at pH 5 using dilute HNO3 with a gelling time of 5 days. Supernatant solutions of (NH4)2C2O4 and Co(NO3)2/KSCN were added on each side of the tube. The Co(NO3)2 and KSCN were firstly mixed before adding onto the gel to increase the possibility of thiocyanate doping in the crystals. Various molar ratio of Co(II):C2O4
−2:SCN− were used (1:1:0, 1:1:1, 1:1:2, 1:1:3, 1:1:4, and 1:1:5). FT-IR and SEM were used to analyse the crystal. The result shows that red block crystals were formed. FTIR analysis for all molar ratios reveals that they all give considerably identical spectra with an absence of thiocyanate peaks around 2200 cm−1, suggesting that all molar ratios give an identical product of cobalt(II) oxalate hydrate. SEM analysis shows that the size of the crystals was significantly bigger than previously reported crystals. The Co(II) centre binds to the oxalate ligand, and not to the thiocyanate, due to chelating effect. However, inconclusive findings were observed regarding the influence of the molar ratio on the crystals yield. The use of a higher concentration of thiocyanate (fivefold molar ratio) did not affect the composition of the product, and the product remains crystallized as cobalt(II) oxalate hydrate.
Isolation and Optical Properties of Natural Pigments from Purple Mangosteen Peels
Authors: Kurniawan Yehezkiel Steven , Fahmi M. Riza Ghulam , Yuliati Leny
Published: July 2020

Purple mangosteen (Garcinia mangostana) has several biological applications such as anticancer, antitubercular and antioxidant agents. In this work, we isolated and studied the optical properties of the natural pigments from the purple mangosteen peels. To isolate the natural pigments, the mangosteen peels were macerated using distilled water, ethanol, or acetone for 24 h. The extracts were filtrated and characterized using spectrophotometers of Fourier transform infrared (FTIR), ultraviolet-visible (UV-Vis), and spectrofluorometer. The extracts gave the FTIR vibration peaks of O-H, C-H sp3, C=O, C=C, and C-O functional groups, while absorption peaks at 210–374 nm were observed in the UV-Vis spectra of the extracts due to the presence of mangostins, anthocyanins, and phenolic acids. The three-dimensional fluorescence spectra showed that the excitation and emission peaks of the mangosteen peels extracted with ethanol were found at 444 and 498 nm, respectively, while that extracted with distilled water gave no significant fluorescence peaks. On the other hand, the mangosteen peels extracted with acetone gave the strongest emission intensity at 472 and 502 nm due to the most intense color intensity. This study provided useful information about the optical properties of natural pigments extracted from purple mangosteen peels through a simple isolation technique.
Effects of Growth Medium on Extracellular Secretion of Human Epidermal Growth Factor in Escherichia coli by Co-expression with Bacillus cereus Phospholipase C
Authors: Latifah F P U , Indriyani A , Pratiwi R D , Sriwidodo  , Maksum IP
Published: July 2020

Human Epidermal Growth Factor (hEGF) is a small, mitotic growth polypeptide that promotes the proliferation of various cells and is widely applied in clinical practices, especially in therapeutic uses of wound healing. Since it has a lot of benefits, production of recombinant hEGF (rhEGF) in a large scale is needed. Some methods have been used in this protein production, one of them was the production of rhEGF using extracellular secretion in Escherichia coli. Previous research have been done using co-expression method with phospholipase C from Bacillus cereus to increase the amount of rhEGF. Phospholipase C B. cereus have been used in several protein expression and was proved that it could increase the secretion of recombinant protein through hydrolytic mechanism of cell membrane. In addition, growth condition is one of some major factors which can affect the yields of produced protein. Different compositions of bacterial growth medium often lead to different result. This paper studies how rich-nutrient Terrifict Broth (TB) medium and Luria Bertani (LB) medium produced different rhEGF results when it was co-expressed with phospholipase C B. cereus. rhEGF was characterized using SDS-PAGE and confirmed by western blot using anti-mouse EGF, and its concentration was measured using ELISA. rhEGF was successfully characterized after co-expression in TB medium and the concentration was 503.48 μg/mL. rhEGF was better produced in TB medium rather than in LB medium since TB medium has richer composition.
Antibacterial Activity of Free Fatty Acids, Potassium Soap, and Fatty Acids Methyl Esters from VCO (Virgin Coconut Oil)
Authors: Mena T P , Sutrisno  , Marfu’ah S
Published: July 2020

Virgin coconut oil is edible oil obtained from fresh coconut meat (Cocos nucifera L.) and is widely used for health such as for alternative healthy diets, anti-bacterial, anti-virus and anti-fungal. This is because VCO contains a lot of MCFA (Medium-Chain Fatty Acids) such as lauric acid (65.84%), myristic acid (13.16%) and caprylic acid (7.08%). The antibacterial ability of MCFAs is one of the most studied, but free fatty acids from the hydrolysis of VCO have not been done. The objective of the research is to derivatize VCO and determine the potential antibacterial activity of the product. The results of the research are as follows. (1) K-soap (solid, white, melting point 46-124 °C). (2) Free fatty acids (liquid, colorless, boiling point 266-296 °C, density 0.93 g.mL−1, refractive index 1.44, viscosity 27.18 cP, acid value 184.54, saponification value 296.59 and ester value 112.05). (3) Fatty acid methyl ester (liquid, colorless, boiling point 260-262 °C, density 0.89 g.mL−1, refractive index 1.43, viscosity 3.36 cP, acid value 0.33, saponification value 268.6 and ester value 268.27). VCO and its derivatives at concentrations of 2 and 1% are active as antibacterial agents against Escherichia coli and Staphylococcus aureus.
Essential Oil Extraction of Cananga odorata Flowers using Hydrodistillation and Steam-Water Distillation Processes
Authors: Oktavianawati Ika
Published: July 2020

This paper discussed about the effect of distillation processes in the extraction of cananga essential oil from Cananga odorata.In this research, cananga oils were extracted by steam-water distillation and hydrodistillation processes. The equipment used in this current research is a distillation home scale set-up plant which further will be applied on cananga local farmer in Sukorambi region, Jember district. Therefore, preliminary optimization process for this distillation equipment was required. The distillation batch (retort) contained 2 kg of cananga flowers and 20 L of water. Based on research result, the distillation equipment could run hydrodistillation process for 3 hours, while in steam-water distillation set-up could only run for 2 hours. The volume of water in distillation batch was a limiting factor in both processes. In general, the yield of essential oil was increase along the longer of distillation time that have been applied. However, the result showed that essential oil from hydrodistillation for 1 hour had the best quality compared to other distillation conditions, in terms of its volatile compound contents. Oxygenated hydrocarbons content in cananga oil from 1 hour hydrodistillation process (56.5%) was highest compared to 2 and 3 hour hydrodistillation (35.48% and 22.36%, respectively), and even to essential oil from steam-water distillation process (43.25%). Generally, extra grade cananga oil was markedly by the high content of esters, and linalool, but low in β-caryophyllene content. These characteristics could be found in cananga oil obatined from hydrodistillation process for 1 hour which contained major volatile compounds, i.e. geranyl acetate (16.58%), benzyl benzoate (13.38%), β-caryophyllene (16.35%), germacrene D (15.3%), and farnesol (9.54%). However, linalool was only found in cananga oil from steam-water distillation. Therefore the current distillation condition, hydrodistillation for 1 hour, would be applied in distillation of cananga oil at Jember local community.
Preliminary Study on The Development of Preconcentration Method of Cu(II), Co(II), Ni(II), and Cr(III) Ions in Water Samples Using Nanomagnetite Coated by Carboxymethyl kappa-Carrageenan (CMKC)
Authors: Purnama Nuridhia Nisa , Kusumaningrum Irma Kartika , Wijaya Anugrah Ricky , Utomo Yudhi , Arief Munzil , Nostia Rohima , Findiyani Lutfiyah
Published: July 2020

Flame Atomic Adsorption Spectrophotometry (FAAS) is one of the instruments that is often used to determine metal ion concentration in solution. FAAS uses simple operational procedure for metal ions concentration determination and produces accurate metal ion concentrations. Unfortunately, the accuracy of metal ion determination test decreases if the concentration of metal ions is too low, whereas the threshold for metal ions in drinking water is very low. Preconcentration is a method for increasing the concentration of metal ions in sample. An effective preconcentration method needs to be studied to improve the accuracy in the determination of metal ions concentration in water at low concentration using FAAS. This research aims to determine the effectiveness of metal ions preconcentration in water samples using nanomagnetite coated by CMKC. The research was conducted in four stages, 1) synthesis of nanomagnetite coated by CMKC; 2) preconcentration of samples containing Cu(II), Co(II), Ni(II), and Cr(III); 3) measurement of metal ion concentration with FAAS; 4) effectivity of preconcentration process and preconcentration optimum conditions. The result showed that nanomagnetite coated by CMKC can be used to preconcentration of metal ions Cu(II), Co(II), Ni(II), and Cr(III) in water samples by utilizing desorption-adsorption mechanism. Desorption was done using 0.1 N HNO3 as a desorption solvent without variation in concentration and desorption time preconcentration optimum conditions for each metal ion were as follows, adsorption condition of Ni(II) was pH 7 and 60 minutes; Cr(III) was pH 7 and 40 minutes; Co(II) was pH 7 and 60 minutes; Cu(II) pH 6 and 40 minutes. The effectiveness of preconcentration at optimum conditions for each metal ions are: %Cr(III) > %Cu(II) > % Co(II) > %Ni(II), successively.
Preparation of Curcumin Nanoemulsion in Soybean Oil – Tween 80 System by Wet Ball Milling Method
Authors: Sholihat Shobbu Ibabas , Indahyanti Ellya , Lestari Maria Lucia A.D , Ningsih Zubaidah
Published: July 2020

Curcumin nanoemulsion which has a particle size of 20-200 nm, is one of the curcumin drug delivery system that can increase curcumin solubility and bioavailability. The previous method of curcumin nanoemulsion formulation is modified thin-film hydration followed by sonication that has a long process and using organic solvent. This study aims to make curcumin nanoemulsion by wet ball milling method in soybean oil – Tween 80 system. Nanoemulsion is expected to have smallest particle size, high curcumin loading capacity and good stability during storage. Preparation of curcumin nanoemulsion is done by wet milling method which consists of curcumin as drug, soybean oil as curcumin solvent, tween 80 as stabilizer, water as dispersed medium and milling beads as milling media on the vial with various milling time. Particle size and polydispersity index are monitored using dynamic light scattering while nanoemulsion morphology is observed using digital imaging microscope. Results show that optimum milling times is 24 h and the highest curcumin added which produces less than 500 nm particles is 300 mg which is stable during 60 days of storage. Particle size of the nanoemulsion is ranging from 127 – 338 nm. In addition, wet ball milling methods is relatively simple and easy to apply.
Characterization of Slow Pyrolysis Products of Macaranga motleyana: Effect of Sample Size
Authors: Nurlianti Subagyono RR Dirgarini Julia , Puspitasari Rika , Sanjaya Ari Susandy , Suwinarti Wiwin
Published: July 2020

The characterization of biocrude oil produced by slow pyrolysis of fast growing wood Macaranga motleyana has been conducted. Slow pyrolysis was carried out in a fixed bed pyrolysis reactor at 500 °C for 1 hour with a variety of wood sample size. The decrease of a sample size from 20 to 40 mesh resulted in an increased in the percent yields of liquid product, which were 28.5 wt.% and 36.1 wt.%, respectively. Characterization of the biocrude oil showed that the pH of the biocrude oil was 2, the density of biocrude oil was 1.132 g/mL, while the viscosity value of the biocrude oil was 53.6 cSt. Analyses of the biocrude oil using a Gas Chromatography-Mass Spectrometry (GC-MS) revealed that the biocrude oil derived from Macaranga motleyana wood contained phenol and its derivatives, such as eugenol and compounds resulted from thermal degradation of cellulose or hemicellulose. The use of sample with a smaller sample size resulted in biocrude oil containing more chemical compounds.
Indirect Spectrophotometry Method Based on the Formation of Chromium(VI)-Diphenylcarbazide Complex for Determination of Hydroquinone in Cosmetics
Authors: Sulistyarti Hermin , Sari Puspita Mufidah , Syamaidzar  , Retnowati Rurini , Tolle Herman , Wiryawan Adam
Published: July 2020

This research is focused on the development of a new indirect spectrophotometry for the determination of hydroquinone in cosmetics based on the capability of hydroquinone as reducing agent for chromium(VI). The principle of the determination is based on the decrease of the color intensity of the red-violet complex of chromium(VI)-Diphenylcarbazide (DPC) due to the reduction of the available chromium(VI) by hydroquinone to chromium(III). Thus, only the remaining chromium(VI) reacted with DPC to form a red-violet complex detected by spectrophotometry at 542 nm. All chemical parameters were optimized with respect to sensitivity and selectivity of measurements. Under the obtained optimum conditions (reaction time of 5 minutes, chromium(VI) of 1 mgL−1, sulfuric acid of 0.05 M, and DPC of 0.0125%), the method gave linear calibration for hydroquinone concentration from 0.2-2.5 mgL−1 (R2 = 0.996). The proposed method also provided good sensitivity shown by low values of LoD and LoQ (0.07 and 0.1 mgL−1) and satisfactory selectivity towards the common interfering ions present in cosmetics. Satisfactory results with recoveries of close to 100 % were observed when the method was applied to facial whitening and black spot removal cosmetics. This result suggests that the developed method is able to be used for monitoring of hydroquinone in skin lightening cosmetics.
Anti-inflammatory Activity of Neuropathic Pain Reducing Herbal Medicine Based on Edema Inhibition of CARR-induced Sprague Dawley Paws
Authors: Tristantini Dewi , Hanifah Aisyah , Pramadhanya Raiska Bani
Published: July 2020

Neuropathic pain is nerve pain whose treatment still has side effects when used for the long term. Regulation and modulation of the immune system is needed to reduce the inflammatory reaction that triggers of the pain. Increasing neural tension may induced with nerve inflammation which producing compounds responsible for signalling pain, fever and heat. Ginger (Zingiber officinale Roscoe), cloves (Syzygium aromaticum L.) and nutmeg (Myristica fragrans Houtt) have been known to contain phenolic compounds that are efficacious as anti-inflammatory agents. This study aims to prove the anti-inflammatory activity of neuropathic pain reducing herbs consisting of a combination of the three ingredients. Result from herbs formulation and reflux extraction then analysed for anti-inflammatory activity using in vivo & Winter method with Sprague-Dawley white male rats (Rattus norvegicus) and quantitative phenol content. Anti-inflammatory analysis done by 6 groups of rats, which is normal control, negative control, positive control, dosage I (given herbal extract 1.125 mL/200 g BW), dosage II (given herbal extract 2.25 mL/200 g BW) and dosage III (given herbal extract 4,5 mL/200 g BW). Anti-inflammatory of 10 g herbs extract in 250 mL solvent then observed through the inhibition of oedema formation on rats’ paw along the time. Dosage III group has the higher inhibition percentage as in 75.76%, which almost equivalent as normal control group (82.28%).
Solvent Effect at Ibuprofen Adsorption Using Zinc Oxide Plate Rod-Like from Gelatine
Authors: Ulfa Maria , Purnama Ali Muh Ari
Published: July 2020

The ubiquitous occurrence of several pharmaceuticals in sewage effluents has led to the considerable deterioration of some life forms and the quality of the receiving water bodies. Ibuprofen is a nonsteroid anti-inflammatory drug, represents a diverse class of drugs andthe most commonly used analgesics for the management of pain and/or inflammation associated with rheumatoid arthritis and osteoarthritis, muscle stiffness and pain, dental pain, migraine, and headache. The present work investigated the effect of different solvents on ibuprofen dissolution during the adsorption of Ibuprofen on to zinc oxide plate rod-like from its hexane, methanol, ethanol solutions, and water as co-solvents. The zinc oxide plate rod-like was synthesized using block copolymer and gelatine as a template and zinc sulphate as zinc precursor was then characterized by X-ray diffraction, scanning electron microscopy, and FTIR to analyse the structure and morphology. The impact of various solvents on the percentage removal (%) of Ibuprofen was determined by batch adsorption experiments. The data obtained were subjected to isotherm and kinetic analysis to describe the distribution of ibuprofen between the liquid and solid phases in the batch studies. The results obtained best fitted the Langmuir isotherm model with an adsorption capacity close to 110mg/g at room temperature with an initial concentration of 100 ppm. To sum up, for large-scale removal, ibuprofen treatment for aquatic, zinc oxide plate rod-like maybe an adsorbent in future.
In Silico Analysis of Saponin Isolates from Mesocarp of Cucumber (Cucumic sativus L.) and Purple Eggplant (Solanum melongena L.) as Pancreatic Lipase Inhibitor
Authors: Wijaya Mely , Subandi
Published: July 2020

Currently orlistat has been widely used as anti-obesity drug, because of its activity as a pancreatic lipase inhibitor. Two saponin isolates, from cucumber mesocarp and purple eggplant, also proved to be active as pancreatic lipase inhibitors in vitro. Based on spectrophotometric analysis, the two saponin isolates are thought to be Silphioside F and Cesdiurins I-III. The purpose of this study is to confirm the ability of the two compounds as pancreatic lipase inhibitor through in silico analysis, relative to orlistat. This study uses Python Molecular Viewer (PyMol), Python Prescription (PyRx) 0.8, and Discovery Studio software. As a ligand, 3D structure of Silphioside F and Cesdiurins I-III have been used. The orlistat as a comparative ligand molecule have also been used. 3D structure of porsine pancreatic lipase has been used as receptor molecule. The result of the analysis shown that the binding site of pancreatic lipase is relatively same as orlistat of Cesdiurins I-III molecule, but different for the Silphioside F molecule. The data indicated that in inhibiting pancreatic lipase, the two isolate compounds used different mechanism. However, against pancreatic lipase, both molecules have greater binding affinities each, compared to orlistat, which were -9.7 kcal/mol for Silhphioside F and -9.5 kcal/mol for Cesdiurins I-III, and orlistat only -7.6 kcal/mol. The latest data were in line with the in vitro analysis, that both isolates have greater inhibition power than orlistat.
Effect of NaCl Addition and The Incubation Time on Gallic Acid Concentration in Cabbage Fermentation using Lactobacillus plantarum and The Potential as Antioxidant
Authors: Zuhria Viky Arina , Srihardyastutie Arie , Safitri Anna , Prasetyawan Sasangka
Published: July 2020

Cabbage is one type of vegetable that is often consumed. Cabbage contains gallic acid and sulforaphane compounds which potentially used as an antioxidant. Gallic acid and sulforaphane are produced from the hydrolysis reaction, which occurs by fermentation. Therefore, this research was focused on the effect of NaCl addition and the incubation time on the gallic acid concentration during cabbage fermentation using L. plantarum. The addition of NaCl used were 0 %, 0.5 %, 1.0 %, 1.5 %, and 2.0 % (w/v). While the incubation time used were 2, 3, 4, 5, and 6 days. The fermentation conditions used were 5 % (v/v) inoculum volume and pH 6. Gallic acid in fermented cabbage (biomass and filtrate) were determined using Folin-Denis method. The antioxidant analysis was determined using DPPH method. The optimum conditions were obtained at the addition of 1.0 % NaCl for 4 days fermentation. During these conditions, the gallic acid produced in biomass and filtrate were equal to 4.726 mg/100 g FW and 147.857 mg/100 g FW, respectively. Sulforaphane and gallic acid have potential as antioxidants with IC50 valuesof 95.113 mg/L and 21.648 mg/L, respectively.
Voltammetric Determination of Paracetamol using Polyvinyl Alcohol (PVA)-Fe3O4Modified Glassy Carbon Electrode
Authors: Andawiyah Robi’atul , Mulyasuryani Ani , Sulistyarti Hermin
Published: July 2020

Modifications of glassy carbon electrodes (GCE) as working electrodes have been carried out by polyvinyl alcohol (PVA)-Fe3O4membranes. The PVA-Fe3O4membrane was superimposed on the surface of a glassy carbon electrode. This study influences the percentage of paracetamol in the membrane, the effect of modulation time, the effect of modulation amplitude, the effect of scan rate, the effect of pH and supporting electrolytes. The performance evaluation of the modified electrode was based on a voltammogram of cyclic voltammetry (CV) and the analysis was carried out with a differential pulse voltammetry (DPV) method. The effect of pH was studied in the range of 2-7 by Britton – Robinson buffer. The results showed that the percentage of paracetamol in the membrane affected the diffusion of current. The best performance of GCE modified was produced by a membrane with paracetamol percentage of 3% (w/w). The optimum operational condition of the instrument was at modulation amplitude of 10 mV, the modulation time of 0.1 s and the scan rate of 12.5 mV/s. pH affects the shift of the anodic peak of paracetamol in a more negative direction. The results of the analysis of paracetamol using DPV method showed that more sensitivity was achieved when phosphate buffer as a supporting electrolyte was used. The sensitivity of the GCE modified by the PVA-Fe3O4membrane was 0.2922 µA/µM in the linear concentration range of 0-100 µM and limit of detection (LoD) of 8 µM.
The Effect of Acid Type in Mechanochemical Treatment of Rice Husk Ash for Concrete Application
Authors: Fatriansyah J F , Khairunnisa S A , Dhaneswara D , Rahmatullah M Z , Ramadhan B A
Published: July 2020

Concrete was successfully produced using rice husk ash (RHA) as a partial cement substitute. RHA was mechanochemically treated using ball mill as mechanical force and acids (HCl and CH3COOH) as chemical force. Mechanochemical treatment decreases particle size as demonstrated by particle size analyser test and reduces crystallinity of RHA as demonstrated by X-ray diffraction analyses. These characteristics make RHA more suitable as partial substitution of cement as well as pozzolanic material. The compressive strength of concrete increases 11-26 % by addition of RHA as cement substitution. The significant increase of compressive strength was obtained from RHA mechanochemically treated with HCl which has compressive strength of 14.8 MPa in comparison of standard concrete which has compressive strength of 11.72 MPa.
Synthesis and Characterization of Chitosan Membrane as a Matrix in Drug Delivery of Curcumin
Authors: Hastuti Budi , Assya’adha Alfiah
Published: July 2020

This study aims to find out how to synthesize the chitosan membrane contained curcumin and its characteristics. The characterization of chitosan membrane was determined use FTIR for functional group analysis, XRD for crystallinity and SEM to show the surface of morphology and cross-section on the chitosan membrane. Curcumin encapsulated into the chitosan membrane was performed by using UV-Vis spectrophotometry at λ 426 nm. The results of this study indicate that the chitosan membrane synthesized was obtained homogeneous clear yellow membrane sheets. The characterization of FTIR instrument obtained that chitosan membrane have peaks at wavenumber of 3425.58 cm−1 that show OH groups and 1627.92 cm−1 which show the presence of amine groups. While XRD characterization show chitosan membrane was semi-crystalline which was shown by a high peak intensity with angles 2θ 4.1604 and 2θ 3.8711. According to the SEM photo shows a smooth and even surface morphology. The optimum time for encapsulation of curcumin into the chitosan membrane is 60 minutes with % EE of 14%.
Modification of Gunung Kidul Natural Zeolite and Its Application in the Corrosion Rate Reduction of Steel Plates in Acid Media
Authors: Khafid Mohammad Abdul , Wicaksono Aditya Pandu , Andita Firstyananda Wahyu , Nurdina Asifa Ihya
Published: July 2020

The use of metals in the industry plays a very important role, where nearly 90% of industrial equipment comes from metallic materials. Corrosion is an electrochemical process between metals with its environment that can damage the metal quality. Gunung Kidul natural zeolite can be modified into a mixture of alkyd paint as a coating material to reduce the corrosion rate of steel plates effectively. In this research, the zeolite was activated by NaOH 1 N for 120 minutes. The zeolite was characterised using Surface Area Analyzer (SAA) and nitrogen adsorption analysis to investigate the surface area of zeolite by Brunauer-Emmet-Teller (BET) modelling. The lining was done by coating the steel plates by alkyd-zeolite paints and inserted into a 100 mL H2SO4 1N, 2N, and 3N for 20 days. The results of this study showed that the corrosion rate of steel plate was 0.1374 miles/year (uncoated), 0.0407 miles/year (coated by alkyd paint), and 0.0095 miles/year (coated by alkyd paint-zeolite). Using activated zeolite as a mixture of alkyd paint is environmentally friendly and effective in lowering the corrosion rate of mild steel plates.
Synthesis of ZnO-Ag with Clove Oil Using Ultrasonication Method and Its Antibiofilm Activity Against Klebsiella pneumoniae
Authors: Nisyak K , Prasetya Y A , Hisbiyah A , Iftitah E D , Srihardyastutie A
Published: July 2020

ZnO-Ag nanocomposite synthesis has been successfully carried out by ultrasonication using clove oil as a reducing agent. Synthesis reactions were carried out in 30, 60, 90, 120, 240, and 300 minutes time variations. ZnO-Ag crystallinity was analyzed using X-Ray Diffractometer (XRD) and the average particle size was calculated using Scherrer equation. The morphology of ZnO-Ag which has the smallest particle size was analyzed by Scanning Electron Microscope -Energy dispersive X-Ray Spectroscopy (SEM-EDX). ZnO-Ag antibiofilm activity against Klebsiella pneumoniae was determined by microtiter plate test. Based on research that has been done, the best time for synthesizing ZnO-Ag with clove oil through ultrasonication is 90 minutes, the resulting particle size of 21.46 nm with the composition of 51.4% Ag (cubic), 20% wulfingite (orthorhombic), 22.9% Zn(OH)2 (orthorhombic), and 5.7% ZnO (cubic). ZnO-Ag has strong antibacterial activity against K. pneumoniae and can inhibit the growth of K. pneumoniae biofilms.
Effect of Water Depth and Flow Velocity on Microstructure, Tensile Strength and Hardness in Underwater Wet Welding
Authors: Paundra F. , Anindito J. , Muhayat N. , Saputro Y. C. N. , Triyono
Published: July 2020

Wet underwater welding is a welding process carried out under water. The depth and water flow velocity greatly affect the welding results. Thus, a further research needs to be done about the effect of the depth and water flow velocity of underwater wet welding. The research aimed to determine the effect of depth and velocity of water flow on underwater wet welding on physical and mechanical properties. The welding process is carried out by using SMAW method at a depth of 2.5 m and 5 m with variations in water flow velocity of 0, 1, and 2 m/s. Land welding is performed as a comparison. X-ray radiography, micro-structure, tensile strength, and Vickers hardness test were performed to determine the type of welding defects. Radiographic test results indicate an incomplete penetration defect (I), spatter (S), porosity (P), undercut (U), concavity (V), and irregular surface (Z). The results of the micro-structure test show that the grain size is fine and coarse as the depth and velocity of the water flow increase. Tensile strength and micro-hardness testing increase along with an increasing depth and velocity of water flow.
Performance of Additive in Metal Separation from Nickel Ore
Authors: Ghea Puspita Angella Natalia , Kawigraha Adji , Permatasari Nur Vita , Respati Santi Ari
Published: July 2020

The potential resources and reserves of nickel ore in Indonesia is the third largest in the world. The potential quite large, but the nickel content found in nature is very small. To increase the added value of nickel ore, it is necessary to process/refine nickel ore. In addition, coal ratio parameter and process temperature in the reduction process, additive is also used as parameter for the composite reduction process. This research used 6 combination saprolite ore composite based on result of previous research. The objective of this research is to know the performance of additive in separation of metal from nickel ore based on result of XRD analysis. XRD analysis is used to know chemical compound saprolite ore composite after reduction process. This results from XRD analysis shown that additive CaCO3 has the best performance additive with higher Fe and Tetrataenite content with percentage of coal ratio of 30% in temperature of 1300 °C. For additive Ca2SO4 percentage coal ratio 15% have higher Fe and NiFeO content in temperature of 1200 °C and 1300 °C.
Numerical modelling of PCMs encapsulated in spherical shells using inverse enthalpy-temperature functions
Authors: Pop O G , Iuga C A , Tutunaru L. Fechete , Domnita F. , Balan M C
Published: July 2020

The study presents a numerical model that uses the enthalpy method in order to solve the moving boundary problem and to predict the thermal behaviour of phase change materials during solidification and melting. The commercially available paraffin RT21 is considered as phase change material, and the thermophysical properties of the paraffin were determined by differential scanning calorimetry. An inverse enthalpy-temperature function was determined based on the results of the differential scanning calorimetry measurements in order to model the phase change process. The model was experimentally validated, and good agreement was found between the computed and measured results.
Design and Implementation of Interface Circuits Intended for Printed Piezoelectric Micropower Harvesters on Flexible Substrates
Authors: Pandiev I , Aleksandrova M , Kolev G
Published: July 2020

Interface circuits with low power dissipation is proposed and implemented, which is useful for efficient AC/DC voltage conversion of thin-film piezoelectric micro-power stack mounted harvesters. The focus is on low-power (< 1 μW) elements consisting of printed PVDF-TrFE piezoelectric polymer on BaSrTiO3 coated flexible substrate with total thickness of the stack 3.1 μm. Using silver thin films as bottom and top electrodes, the samples exhibited stable piezoelectric rms voltage between 200 mV and 400 mV produced from functional area of ∼1.5 cm2 when stimulates it with sine-wave vibration with frequency of 50 Hz and intensity equivalent to mass loading between 1–80 g. The current registered from a single harvesting element is not greater than 1 μA. For this type of harvesters two power processing circuits intended are designed and built. The first circuit is a voltage doubler, for which the rectified output voltage is approximately equal to twice of the amplitude of the input voltage. The second circuit is a voltage quadrupler; as compared to the first one it provides higher voltage for charging a small and thin-size chip supercapacitor connected to the output port, but due to diodes voltage drops a smaller value of the energy efficiency can be obtained. For the implementation of the electronic circuits, low-power Schottky diodes with a forward voltage below 100 mV at current up to 0.1 mA are chosen. An experimental study to verify the efficiency of the proposed circuits is performed with laboratory made thin-film piezoelectric harvesters.
Bioprinting of an osteocyte network for biomimetic mineralization
Authors: Yang Yiqi , Wang Minqi , Yang Shengbing , Lin Yixuan , Zhou Qinghui , Li Hanjun , Tang Tingting
Published: July 2020

Osteocytes, essential regulators of bone homeostasis, are embedded in the mineralized bone matrix. Given the spatial arrangement of osteocytes, bioprinting represents an ideal method to biofabricate a 3D osteocyte network with a suitable surrounding matrix similar to native bone tissue. Here, we reported a 3D bioprinted osteocyte-laden hydrogel for biomimetic mineralization in vitro with exceptional shape fidelity, a high cell density (107 cells per ml) and high cell viability (85%–90%). The bioinks were composed of biomimetic modified biopolymers, namely, gelatine methacrylamide (GelMA) and hyaluronic acid methacrylate (HAMA), with or without type I collagen. The osteocyte-laden constructs were printed and cultured in mineralization induction media. After 28 d, increased dendritic cell connections and enhanced mineralized matrix production were observed after the addition of type I collagen. These results were further confirmed by the expression of osteocyte-related genes, markers of osteocyte morphology (Connexin43 and E11/Podoplanin), markers of mineralization (dentin matrix acidic phosphoprotein 1 (Dmp1)) and the cellular response to parathyroid hormone (PTH). Moreover, the 3D bioprinting constructs outperformed the 2D monolayer culture and they were at least comparable to 3D casted hydrogels in mimicking the natural osteocyte phenotype. All results indicated that the 3D bioprinting osteocyte network shows promise for mechanistic studies and pharmaceutical screening in vitro.
Application of β-diketone boron complex as an ultraviolet absorber in polyvinyl chloride film
Authors: Ma Xiaohong , Gao Huaizhi , Lu Yunhua , Liu Xingliang , Dang Li , Xu Shiai
Published: July 2020

In this paper, β-diketone boron complex (BF2-TPE) was first used as an ultraviolet (UV) absorber for polyvinyl chloride (PVC), and then a series of PVC/BF2-TPE composite films were prepared by solvent casting method. UV accelerated aging experiment was conducted to evaluate the effect of BF2-TPE on the photooxidative degradation of PVC, the structure and properties of the composite films in the UV aging process were characterized by ultraviolet-visible absorption spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis and mechanical property analysis. The results show that BF2-TPE can absorb UV light in the wavelength range of 220–450 nm. The yield strength of the PVC/BF2-TPE composite film with 0.5% BF2-TPE (PVC/BF2-TPE0.5) decreases from 10.5 MPa to 7.8 MPa after 1200 h of UV irradiation, and its retention ratio is much higher compared with that of pure PVC film, indicating that BF2-TPE can inhibit the photooxidative degradation PVC. The PVC/BF2-TPE0.5 composite film shows higher temperature of onset decomposition, indicating that BF2-TPE can also enhance the thermal stability of PVC/BF2-TPE composite films.
Solution-processable electronic and redox-active liquid crystals based on the design of side chains
Authors: Funahashi Masahiro
Published: July 2020

For the development of solution-processable functional materials, it is significant to increase the solubilities of the materials for organic solvents, retaining ordered structures of functional π-conjugated units during an evaporation process of solvents. For this purpose, not only a design of π-conjugated functional units but also a design of side chains is indispensable. In addition to alkyl side chains utilized for liquid crystals and conjugated polymers, oligosiloxane, oligoethylene oxide, perfluoroalkyl side chains are discussed in this review. Oligosiloxane side chains remarkably increase the solubilities of π-conjugated liquid crystals and conjugated polymers while the side chains promote self-organization of π-conjugated units to enhance their functions. In the thin films of the liquid crystals and conjugated polymers bearing cycloterasiloxane rings, liquid crystalline nanosegregated structures can be immobilized by an exposure to acid vapors. Oligoethylene oxide chains also promote nanosegregation and coordinate with ionic species. This property provides liquid crystals with electrochemical functions. Perfluoroalkyl side chains reinforce nanosegregated structures to enhance device performances. The electroluminescence devices using π-conjugated liquid crystals and polymers can emit linearly polarized light. Field-effect transistors comprising liquid crystalline active layers provide flexible devices with high performance. Solar cells based on liquid crystalline nanosegregated structures have a potential for high performance devices, due to high carrier mobility in the liquid crystal phases. The π-conjugated liquid crystals bearing oligoethylene oxide chains and ionic moieties form thin films in which electrons and ions are conducted separately, resulting in a new kind of electrochemical devices.
Materials, design, and fabrication of shape programmable polymers
Authors: Kuang Xiao , Roach Devin J , Hamel Craig M , Yu Kai , Qi H Jerry
Published: July 2020

Programmable matter is a class of materials whose properties can be programmed to achieve a specific state upon a stimulus. Among them, shape programmable materials can change their shape, topographical architecture, or dimension triggered by external stimuli after material fabrication, finding broad applications in smart devices, soft robotics, actuators, reconfigurable metamaterials, and biomedical devices. Shape programmable polymers (SPPs) possess the advantages of low cost, the ability to achieve widely tunable stimuli response, and synthetic flexibility. Recent development has resulted in various new materials and fabrication techniques for SPPs. However, to better design and fabricate SPPs to satisfy specific applications, a more comprehensive understanding of SPPs is required. In this review, we provide state-of-the-art advances in materials, design methods, and fabrication techniques for SPPs. Based on different shape-shifting mechanisms, four most widely studied shape-shifting polymers, including shape-memory polymers, hydrogels, liquid crystal elastomers, and magnetoactive elastomers, are categorized. After outlining the material models of SPPs, the widely used approaches of bilayer, biomimetic, and simulation-guided design, are summarized. For the fabrication side, three main manufacturing techniques for SPPs by replica molding, electrospinning, and 3D printing are reviewed with an emphasis on 3D printing. Finally, the challenges and future perspectives for SPPs fabrication are discussed.
Inert drift system in a viscous fluid: Steady state asymptotics and exponential ergodicity
Authors: Banerjee Sayan , Brown Brendan
Published: July 2020

We analyze a system of stochastic differential equations describing the joint motion of a massive (inert) particle in a viscous fluid in the presence of a gravitational field and a Brownian particle impinging on it from below, which transfers momentum proportional to the local time of collisions. We study the long-time fluctuations of the velocity of the inert particle and the gap between the two particles, and we show convergence in total variation to the stationary distribution is exponentially fast. We also produce matching upper and lower bounds on the tails of the stationary distribution and show how these bounds depend on the system parameters. A renewal structure for the process is established, which is the key technical tool in proving the mentioned results.
XII—The Distinction in Kind between Knowledge and Belief
Authors: Antognazza Maria Rosa
Published: July 2020

Drawing inspiration from a well-attested historical tradition, I propose an account of cognition according to which knowledge is not only prior to belief; it is also, and crucially, not a kind of belief. Believing, in turn, is not some sort of botched knowing, but a mental state fundamentally different from knowing, with its own distinctive and complementary role in our cognitive life. I conclude that the main battle-line in the history of epistemology is drawn between the affirmation of a natural mental state in which there is a contact between ‘mind’ and ‘reality’ (whatever the ontological nature of this ‘reality’) and the rejection of such a natural mental state. For the former position, there is a mental state which is different in kind from belief, and which is constituted by the presence of the object of cognition to the cognitive subject, with no gap between them. For the latter position, all our cognition is belief, and the question becomes how and when belief is permissible.
Dense and sparse vertex connectivity in networks
Authors: Djellabi Mehdi , Jouve Bertrand , Amblard Frédéric
Published: July 2020

The different approaches developed to analyse the structure of complex networks have generated a large number of studies. In the field of social networks at least, studies mainly address the detection and analysis of communities. In this article, we challenge these approaches and focus on nodes that have meaningful local interactions able to identify the internal organization of communities or the way communities are assembled. We propose an algorithm, ItRich, to identify this type of nodes, based on the decomposition of a graph into successive, less and less dense, layers. Our method is tested on synthetic and real data sets and meshes well with other methods such as community detection or $k$-core decomposition.