bluuebunny/crossref_metadata_2025 huggingface dataset:
Cations and Related Soil Variables as the Basis for Nutrients Management Strategies in Central Ethiopian Agricultural Soils - I
Authors: Menna Assefa
Published: September 2019

The study was aimed at assessing the fertility status of soils with special emphasis on cation “concepts” and related physico-chemical variables as decision-support tools in making fertilizer recommendations. Thirty six soil samples collected from three representative locations, namely Arsi (Ar), East-Shewa (ES) and West-Shewa (WS) were considered. The results of the study showed that all the studied soils were salt-free or had no sodicity problems. But, the exchangeable aluminum (Al3+) was detected in some 20.8% of the sites as a manifestation of strongly acidic soil reactions. In all studied soils, the exchangeable potassium (K+) was adequate or even excess in some sites based on the suggested critical thresholds. Some 20.8% of the soils contained low levels of calcium (Ca2+) with values falling below the suggested critical levels. Still some, 12.5% were marginal, leaving 66.7% of the sites to be safe from Ca nutritional problems. Hence, Ca was found to be dominating the soil-colloids, particularly, in the ES zone. Similarly, magnesium (Mg2+) appeared to be deficient in strongly acidic soils (29.2% of the sites). The excess levels of Ca2+, K+ and even Mg2+ were observed in the alkaline soils sampled from ES. In fact, sandy and strongly acidic soils tend to have relative lower levels of the cations, Mg2+ and Ca2+. The overall study revealed that, in addition to the previously reported deficient macronutrients: nitrogen (N), phosphorus (P) and sulfur (S); Mg was also found to be limiting element in some areas followed by Ca. From the micronutrients: boron (B), zinc (Zn), molybdenum (Mo) and iron (Fe) were found to be the most limiting in the studied soils, all in the decreasing order of importance. Therefore, it is suggested that the deficient amounts of nutrients need to be applied and/or formulated for the specific sites, if soil- and plant analytical data are available.
Biofuel Development in Nigeria Production and Policy Challenges
Authors: Oloruntoba Adefarati , Adekanye Paul Kazeem
Published: September 2019

Exploring renewable energy resources stimulates social and clean economic development. The global renewable share in the total primary energy supply is steadily increasing but some countries are not actively contributing to this growth. The current Nigeria dependence on depleting fossil-based fuels can only be changed through a balanced and long-term renewable energy policy that is built on a step by step accomplishment basis. Biofuel remains the sustainable and promising option for Nigeria due to a large biomass reserve of 144 million tons per year. Although, biofuels have been identified as the real deal in increasing energy access, productivity, income, employment generation and also in combating carbon emissions which would invariably check the worst effects of climate change, the existing policies engineered to drive biofuel development are weak resulting into the failure to meeting the national targets; a 10% ethanol blending policy target between 2007-2016, 100% domestic biofuels production target by 2020 and 2000MW of electricity from renewables by the year 2020. Besides the uneven policies menace, lack of incentive, poor energy infrastructure, low cultivation of biomass and yields and non-attractive biofuel market price have been the major obstacles for biofuel development in Nigeria. Nevertheless, active participation of private and public institutions will birth a more realistic policy and a sustainable biofuel production, distribution, market and application in the country.
Direct Synthesis of Sodalite from Indonesian Kaolin for Adsorption of Pb2+ Solution, Kinetics, and Isotherm Approach
Authors: Wahyuni Tri , Prasetyoko Didik , Suprapto Suprapto , Qoniah Imroatul , Bahruji Hasliza , Dawam Ahmad Anwarud , Triwahyono Sugeng , Jalil Aishah Abdul
Published: September 2019

Indonesian kaolin was used as precursor for synthesis of sodalite. Synthesis parameters were optimized by varying the Si/Al ratios, stirring and aging conditions, and water composition. X-ray diffraction (XRD), Fourier Transform Infra Red (FTIR), Scanning Electron Microscope-Energy Dispersive Xray (SEM-EDX), and Particle Size Analyzer (PSA) were used to characterize sodalite. The potential of sodalite as adsorbent for heavy metal Pb2+ ions removal from waste water was investigated in this work. The uptake adsorption capacities of sodalite was 90-100 mg/g from synthesized sodalite crystallized for 24 and 48 hours, and commercial silica. The kinetic of Pb2+ adsorption was a pseudo second order reaction and the adsorption coefficients was followed Langmuir adsorption isotherm.
Operating Conditions and Composition Effect on the Hydrogenation of Carbon Dioxide Performed over CuO/ZnO/Al2O3 Catalysts
Authors: Allam Djaouida , Cheknoun Salem , Hocine Smain
Published: September 2019

A series of catalysts constituted of mixed copper and zinc oxides supported on alumina were prepared by co-precipitation method. The cooper content was in the 10-90 wt.% range. Their catalytic behavior in the hydrogenation of carbon dioxide to methanol was investigated at high pressure (up to 75 bars). The catalysts were characterized by elemental analysis, N2-adsorption, N2O-chemisorptions, and X-ray diffraction (XRD). The catalysts showed a clear activity in the hydrogenation reaction that could be correlated to the surface area of the metallic copper and to the reaction pressure. The CuO/ZnO/Al2O3 catalyst with a Cu/Zn/Al weight ratio of 60/30/10, exhibits the highest carbon dioxide conversion and methanol selectivity. Finally, a mechanism pathway has been proposed on copper active sites of (Cu0/CuI) oxidation state.
Polyvinylpyrrolidone - Reduced Graphene Oxide - Pd Nanoparticles as an Efficient Nanocomposite for Catalysis Applications in Cross-Coupling Reactions
Authors: Elazab Hany A. , El-Idreesy Tamer T.
Published: September 2019

This paper reported a scientific approach adopting microwave-assisted synthesis as a synthetic route for preparing highly active palladium nanoparticles stabilized by polyvinylpyrrolidone (Pd/PVP) and supported on reduced Graphene oxide (rGO) as a highly active catalyst used for Suzuki, Heck, and Sonogashira cross coupling reactions with remarkable turnover number (6500) and turnover frequency of 78000 h-1. Pd/PVP nanoparticles supported on reduced Graphene oxide nanosheets (Pd-PVP/rGO) showed an outstanding performance through high catalytic activity towards cross coupling reactions. A simple, reproducible, and reliable method was used to prepare this efficient catalyst using microwave irradiation synthetic conditions. The synthesis approach requires simultaneous reduction of palladium and in the presence of Gaphene oxide (GO) nanosheets using ethylene glycol as a solvent and also as a strong reducing agent. The highly active and recyclable catalyst has so many advantages including the use of mild reaction conditions, short reaction times in an environmentally benign solvent system. Moreover, the prepared catalyst could be recycled for up to five times with nearly the same high catalytic activity. Furthermore, the high catalytic activity and recyclability of the prepared catalyst are due to the strong catalyst-support interaction. The defect sites in the reduced Graphene oxide (rGO) act as nucleation centers that enable anchoring of both Pd/PVP nanoparticles and hence, minimize the possibility of agglomeration which leads to a severe decrease in the catalytic activity.
CO2 Reforming of Methane over LaNiO3 Perovskite Supported Catalysts: Influence of Silica Support
Authors: Sellam Djamila , Ikkour Kahina , Dekkar Sadia , Messaoudi Hassiba , Belaid Taous , Roger Anne- Cécile
Published: September 2019

The study presents the dry reforming of methane using natural Kaolin silica as catalyst support. The silica-supported LaNiO3 perovskite catalysts (20LaNiO3/SiO2 and 40LaNiO3/SiO2) and bulk LaNiO3 catalyst were synthesized by auto-combustion method. The resulting catalysts were characterized by X-ray diffraction (XRD), N2 adsorption - desorption isotherm measurement,  scanning electron microscopy (SEM) and temperature-programmed reduction (TPR). After reduction at 700 °C, they were used as catalysts for the reaction of dry reforming of methane into synthesis gas at atmospheric pressure at 800 °C. The reduced 40LaNiO3/SiO2 exhibited high catalytic activity. This result was attributed to the small Ni metallic particles obtained from the reduced perovskite highly dispersed on the support and the good reducibility. The increase of reduction temperature at 800 °C resulted in a further enhancement of the catalytic performance of 40LaNiO3/SiO2 catalyst. Copyright © 2019 BCREC Group. All rights reserved
Pd-Fe3O4/RGO: a Highly Active and Magnetically Recyclable Catalyst for Suzuki Cross Coupling Reaction using a Microfluidic Flow Reactor
Authors: Elazab Hany A. , Siamaki Ali R. , Gupton B. Frank , El-Shall M. Samy
Published: September 2019

There are several crucial issues that need to be addressed in the field of applied catalysis. These issues are not only related to harmful environmental impact but also include process safety concerns, mass and heat transfer limitations, selectivity, high pressure, optimizing reaction conditions, scale-up issues, reproducibility, process reliability, and catalyst deactivation and recovery. Many of these issues could be solved by adopting the concept of micro-reaction technology and flow chemistry in the applied catalysis field. A microwave assisted reduction technique has been used to prepare well dispersed, highly active Pd/Fe3O4 nanoparticles supported on reduced graphene oxide nanosheets (Pd-Fe3O4/RGO), which act as a unique catalyst for Suzuki cross coupling reactions due to the uniform dispersion of palladium nanoparticles throughout the surface of the magnetite - RGO support. The Pd-Fe3O4/RGO nanoparticles have been shown to exhibit extremely high catalytic activity for Suzuki cross coupling reactions under both batch and continuous reaction conditions. This paper reported a reliable method for Suzuki cross-coupling reaction of 4-bromobenzaldehyde using magnetically recyclable Pd/Fe3O4 nanoparticles supported on RGO nanosheets in a microfluidic-based high throughput flow reactor. Organic synthesis can be performed under high pressure and temperature by using a stainless steel micro tubular flow reactor under continuous flow reaction conditions. Optimizing the reaction conditions was performed via changing several parameters including temperature, pressure, and flow rate. Generally, a scalable flow technique by optimizing the reaction parameters under high-temperature and continuous reaction conditions could be successfully developed.
Evaluation of Simultaneous Saccharification and Fermentation of Oil Palm Empty Fruit Bunches for Xylitol Production
Authors: Burhan Khairul Hadi , Kresnowati Made Tri Ari Penia , Setiadi Tjandra
Published: September 2019

The biological process route of xylitol production from lignocellulosic materials, via enzymatic hydrolysis which is followed by fermentation, offers a more sustainable or greener process than the chemical process route. Both the enzymatic hydrolysis and the fermentation processes are conducted at moderate process condition and thus require less energy and chemicals. However, the process proceeds slower than the chemical one. In order to improve process performance, the enzymatic hydrolysis and the fermentation processes can be integrated as Simultaneous Saccharification and Fermentation (SSF) configuration. This paper discusses the evaluation of SSF configuration on xylitol production from Oil Palm Empty Fruit Bunches (OPEFB). To integrate two processes which have different optimum temperature, the performance of each process at various temperature was first evaluated. Later, SSF was evaluated at various hydrolysis and fermentation time at each optimum temperature. SSF showed better process performance than the separated hydrolysis and fermentation processes. The best result was obtained from configuration with 72 hours of prior hydrolysis followed by simultaneous hydrolysis and fermentation, giving yield of 0.08 g-xylitol/g-OPEFB.
bcl Morphology Formation Strategy on Nanostructured Titania via Alkaline Hydrothermal Treatment
Authors: Steky Fry Voni , Suendo Veinardi , Mukti Rino Rakhmata , Benu Didi Prasetyo , Reza Muhammad , Adhika Damar Rastri , Tanuwijaya Viny Veronika , Nugraha Ashari Budi
Published: September 2019

Titanium dioxide (TiO2) is a semiconductor material that plays an important role in photocatalysis. Bicontinuous concentric lamellar (bcl) is an interesting morphology with an open channel pore structure that has been successfully synthesized on silica-based materials. If bcl morphology can be applied in TiO2 system, then many surface properties of TiO2 can be enhanced, i.e. photocatalytic activity. A simple and effective strategy has been demonstrated to transform aggregated and spherical TiO2 particles to bcl morphology via alkaline hydrothermal route. Alkaline hydrothermal treatment successfully transforms TiO2 particle surface to have bcl morphology through swelling with ammonia then followed by phase segregation process. We proposed this strategy as a general pathway to transform the particle surface with any shape to have bcl morphology.
Preparation of Polyaniline Emeraldine Salt for Conducting-Polymer-Activated Counter Electrode in Dye Sensitized Solar Cell (DSSC) using Rapid-Mixing Polymerization at Various Temperature
Authors: Amalina Auliya Nur , Suendo Veinardi , Reza Muhammad , Milana Phutri , Sunarya Risa Rahmawati , Adhika Damar Rastri , Tanuwijaya Viny Veronika
Published: September 2019

Polyaniline Emeraldine Salt (PANI ES) as a conductive polymer has been used as a Pt-free counter electrode materials in DSSC. In this study, polymerization temperature was varied at relatively high temperature from 308 to 348 K with respect to the standard low polymerization temperature at 273 K. The synthesis held in varied high-temperature to study the effect of synthesis condition resulted to the performance as counter electrode in DSSC. The effect of high-temperature synthesis condition gives interesting results, the FTIR-ATR spectra show the presence of vibrational modes of phenazine structure obtained at high polymerization temperature, indicate the changing in the chain geometry. Raman Spectroscopy shows the decrease of the I1194/I1623 intensity ratio that can be interpreted that the degree-of-freedom of C-H bond bending mode decreases in the benzenoid ring, while the stretching mode degree-of-freedom along the chain is preserved or increased. The electrical conductivity profile has changed from metal-like at low-temperature into a semiconductor-like profile at high-temperature. Scanning Electron Microscope images reveals that a change in the morphology of PANI ES with temperature. At low-temperature (273 K) the morphology has a globular shape, while at high-temperature it tends to form nanorod structure. DSSC device with highest efficiency is attained for PANI ES polymerized at 273 K (1.91%) due to its high conductivity. The lowest efficiency is observed in device using PANI ES synthesized at 328 K (1.15%) due to its low conductivity due to the formation of phenazine structure.
Synthesis of Spherical Nanostructured g-Al2O3 Particles using Cetyltrimethylammonium Bromide (CTAB) Reverse Micelle Templating
Authors: Benu Didi Prasetyo , Suendo Veinardi , Mukti Rino Rakhmata , Febriyanti Erna , Steky Fry Voni , Adhika Damar Rastri , Tanuwijaya Viny Veronika , Nugraha Ashari Budi
Published: September 2019

We demonstrated the synthesis of spherical nanostructured g-Al2O3 using reverse micelle templating to enhance the surface area and reactant accessibility. Three different surfactants were used in this study: benzalkonium chloride (BZK), sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB). We obtained spherical nanostructured particles only using CTAB that form a reverse micelle emulsion. The particles have wide size distribution with an average size of 2.54 mm. The spherical particles consist of nanoplate crystallites with size 20-40 nm randomly arranged forming intercrystallite spaces. The crystalline phase of as-synthesized and calcined particles was boehmite and g-Al2O3, respectively as determined by XRD analysis. Here, the preserved particle morphology during boehmite to g-Al2O3 transformation opens a facile route to synthesize g-Al2O3 particles with complex morphology. The specific surface area of synthesized particles is 201 m2/g, which is around five times higher than the conventional g-Al2O3 (Aldrich 544833). Spherical nanostructured g-Al2O3 provides wide potential applications in catalysis due to its high density closed packed structure, large surface area, and high accessibility.
Basicity Optimization of KF/Ca-MgO Catalyst using Impregnation Method
Authors: Anggoro Didi Dwi , Buchori Luqman , Sasongko Setia Budi , Oktavianty Herawati
Published: September 2019

This research aimed at determining the optimum value between calcination temperature (X1), calcination time (X2) and %wt KF (X3) toward optimum basicity of KF/Ca-MgO catalyst. Approximately 2-4%wt KF was added to the KF/Ca-MgO catalyst using the impregnation method to assist the Ca-MgO, at 450-550 ºC and a calcination time of 2-4 hours. Furthermore, its basicity was analyzed using Tanabe's titration method. The use of Variance Analysis (ANOVA), indicated that calcination temperature (X1) factor achieved the highest basicity of KF/Ca-MgO catalyst, as indicated by its high F-value (16.46262) and low p-value (0.0067). The correlation between each operating variables and the responses were shown in a mathematical equation. The optimization value is estimated by limiting the calcination temperature from 415.9 to 584.1 ºC, with a calcination time ranging from 1.32 to 4.68 hours, and %wt KF of 1.3182 to 4.6818 % that obtained 1.18 mmol/g for the optimal catalyst basicity.
Synergistic Corrosion Inhibition Effect of Rice Husk Extract and KI for Mild Steel in H2SO4 Solution
Authors: Pramudita Marta , Sukirno Sukirno , Nasikin Mohammad
Published: September 2019

The corrosion inhibition of rice husk extract for bio-corrosion in mild steel in 1 M of H2SO4 solution and the effect of adding potassium iodide were investigated using the weight-loss method with a variable solution temperature and various bio-inhibitor concentrations. The addition of potassium iodide can significantly increase the efficiency of rice husk extract. The highest efficiency is 95.89% at 1,250 ppm of inhibitor concentration at a temperature of 313 K. The inhibition efficiency of rice husk extract is synergistically increased with the addition of potassium iodide. The characteristics of the adsorption inhibitors were assessed using the Langmuir isotherm adsorption approach at all studied concentrations and temperatures. The synergy of rice husk extract and potassium iodide was examined using thermodynamic and kinetic parameters.
Production of Triacetin by Microwave Assisted Esterification of Glycerol Using Activated Natural Zeolite
Authors: Marwan Marwan , Indarti Eti , Darmadi Darmadi , Rinaldi Wahyu , Hamzah Dzikri , Rinaldi Taufik
Published: September 2019

Triacetin, an alternative biodiesel additive, was prepared by esterification of glycerol with acetic acid in the presence of chemically activated natural zeolite. The esterification was carried out in a small reaction flask under microwave irradiation. The catalyst was characterized for its morphology by SEM and its chemical composition by X-ray Diffraction (XRD). The Scanning Electron Microscopy (SEM) micrograph indicates improved surface area of the zeolite, while the XRD analysis shows an increase in Si/Al ratio from natural zeolite to 6.042 and its crystallinity value of 12.23%. The Fourier Transform Infra Red (FTIR) analysis obtained showed that microwave-heated samples have an esters group spectrum of triacetin at 1702 cm-1. The conversion value of glycerol was more than 95% at molar ratio of the reactants 1:9 and catalyst loading of 3%. The selectivities for monoacetin, diacetin and triacetin were 80.1%, 15.4%, and 4.5% at 60 minutes, and 43.0%, 48.6%, and 8.3% at 90 minutes. It shows that the conversion took place in consecutive steps and the use of microwave allows the reaction proceeding at milder condition.
Optimization of Monoglycerides Production Using KF/CaO-MgO Heterogeneous Catalysis
Authors: Buchori Luqman , Anggoro Didi Dwi , Sumantri Indro , Putra Riko Rikardo
Published: September 2019

The production of monoglyceride or monoacylglycerol (MAG) from triglycerides and glycerol has been studied. The purpose of this research was to study the effect of using KF/CaO-MgO catalyst on MAG production with batch reactor. The effect of reaction temperature, reaction time, and catalyst loading was investigated using Response Surface Methods (RSM). The reaction temperature, reaction time, and catalyst loading were varied at 200-220 ºC,  2-4 hours, and 0.1-0.3 % w/w, respectively. The maximum yield of monoglyceride 41.58% was achieved the optimum conditions of  catalyst loading of 0.19 % (w/w), reaction temperature of 208.4 ºC, and reaction time of 3.20 hours.
Synthesis of Solid Acid Catalyst from Fly Ash for Eugenol Esterification
Authors: Hidayati Nur , Pujiati Titik , Prihandini Elfrida B. , Purnama Herry
Published: September 2019

A series of fly ash-based heterogeneous acid catalysts were prepared by chemical and thermal treatment. Fly ash was chemically activated using sulfuric acid and followed by thermal activation. Characterization methods of XRD, BET, SEM-EDX, and the performance in esterification of eugenyl acetate production was carried out to reveal the physical and chemical characteristics of prepared catalysts. Activated catalyst showed high silica content (96.5%) and high BET surface area of 70 m2.g-1. The catalyst was proven to be highly active solid acid catalyst for liquid phase esterification of eugenol with acetic acid yielding eugenyl acetate. A yield of 43-48% was obtained with activated fly ash catalysts for 90 minutes reaction. These catalysts may replace beneficially the conventional homogenous liquid acid to the eco-friendly heterogeneous one.
Effect of Dilute Acid and Alkaline Pretreatments on Enzymatic Saccharfication of Palm Tree Trunk Waste for Bioethanol Production
Authors: Kusmiyati Kusmiyati , Anarki Sakina Tunissa , Nugroho Sabda Wahyu , Widiastutik Reistu , Hadiyanto Hadiyanto
Published: September 2019

The sugar palm tree (Arenga pinnata) was abundant in Indonesia and has high cellulose contents for bioethanol production. However, the lignin content was the major drawback which could inhibit saccharification enzymes and therefore removing the lignin from the biomass is important. This paper evaluated the effects of pretreatments  using nitric acid (HNO3) and ammonium hydroxide (NH4OH) at 2 to 10% (v/v) on reducing sugar and ethanol contents and compared with the effects of steam pre-treatment. The pretreated samples were hydrolyzed using cellulase enzymes at pH 5.0 with a substrate concentration of 10% (w/v) for 24 to 72 h at 50 °C. Subsequent assessments of enzymatic saccharification following pre-treatment with 10% (v/v) HNO3 showed maximum reducing   and total sugar contents in palm tree trunk waste of 5.320% and 5.834%, respectively, after 72 h of saccharification. Following pretreatment with 10% (v/v) of NH4OH, the maximum reducing and total sugar contents of palm tree trunk waste were 2.892% and 3.556%, respectively, after 72 h of saccharification. In comparison, steam pretreatments gave maximum reducing sugar and total sugar contents of 1.140% and 1.315% under the same conditions. Simultaneous saccharification and fermentation (SSF) was conducted at 37 °C (pH 4.8) and 100 rpm for 120 h using 10% (v/v) Saccharomyces cerevisiae and cellulase enzyme with a substrate concentration of 10% (w/v). The result showed the highest ethanol content of 2.648% was achieved by using 10% (v/v) HNO3. The use of 10% (v/v) NH4OH gained a yield of 0.869% ethanol while the steam pretreatment could obtained 0.102% ethanol.
Selective Conversion of 2-Methylfuran to 1,4-Pentanediol Catalyzed by Bimetallic Ni-Sn Alloy
Authors: Rodiansono Rodiansono , Maria Dewi Astuti , Husain Sadang , Nugroho Agung , Sutomo Sutomo
Published: September 2019

The selective conversion of 2-methylfuran (2-MeF) to 1,4-pentanediol (1,4-PeD) over bimetallic nickel-tin alloy catalysts in the ethanol/H2O solvent mixture was studied. By using bulk Ni-Sn(x); x = 3.0 and 1.5 catalysts, a maximum yield of 1,4-PeD (49%) was obtained at 94% conversion of 2-MeF. The dispersion of Ni-Sn(x) on the aluminium hydroxide (AlOH) or g-Al2O3 supports allowed to an outstanding yield of 1,4-PeD (up to 64%) at 433 K, 3.0 MPa of H2 within 12 h. Ni-Sn(3.0)/AlOH catalyst was found to be reusable and the treatment of the recovered Ni-Sn(3.0)/AlOH catalyst with H2 at 673 K for 1 h restored the catalyst’s original activity and selectivity.
Palladium(0) Nanoparticles Immobilized onto Silica/Starch Composite: Sustainable Catalyst for Hydrogenations and Suzuki Coupling
Authors: Sodhi Ravinderpal Kour , Paul Satya
Published: September 2019

The present paper aims to give insight into the art in the field of the synthesis, characterization and applications of Pd(0) nanoparticles immobilized onto silica/starch composite (SS-PdNPs) for hydrogenations and Suzuki coupling. Metal(0) nanoparticles immobilized onto silica/starch composite [SS-MNPs] were prepared from different metal acetylacetonate complexes [Co(acac)2], [Cu(acac)2], [Pd(acac)2],  [Ru(acac)3], [Mn(acac)3], [Co(acac)3] by immobilizing onto silica/starch composite, followed by reduction with NaBH4. Excellent yield of the products, reusability and the facile work-up makes SS-PdNPs a unique catalyst for the reduction of nitroarenes/carbonyl compounds, a,b unsaturated carbonyl compounds and Suzuki coupling under environmentally benign reaction conditions. All the catalysts were characterized by Fourier Transform Infra Red (FTIR), Atomic Absorption Spectroscopy (AAS) analyses,  while the most active catalyst [SS-PdNPs] was further characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).
Inhibition Effect of Ca2+ Ions on Sucrose Hydrolysis Using Invertase
Authors: Hargono Hargono , Jos Bakti , Abdullah Abdullah , Riyanto Teguh
Published: September 2019

Fermentable sugar for bioethanol production can be produced from molasses due to its high sucrose content but Ca2+ ions found in the molasses may affect the hydrolysis. Therefore, this paper was focused to study the effect of Ca2+ ions as CaO on sucrose hydrolysis using invertase and to obtain the kinetic parameters. The kinetic parameters (KM and Vmax) were obtained using a Lineweaver-Burk plot. The value of KM and Vmax parameters were 36.181 g/L and 21.322 g/L.h, respectively. The Ca2+ ions act as competitive inhibitor in sucrose hydrolysis using invertase. Therefore, the inhibition mechanism was followed the competitive inhibition mechanism. The value of inhibition constant was 0.833 g/g. These parameters were obtained from the non-substrate inhibition process because this study used the low substrate concentrations which means the fermentable sugar production was low. Hence, there were still more challenges to studying the simultaneous effect of substrate and Ca2+ on sucrose hydrolysis to produce high fermentable sugar.
Mesoporous ZnO/AlSBA-15 (7) Nanocomposite as An Efficient Catalyst for Synthesis of 3,4-dihydropyrimidin-2(1H)-one via Biginelli Reaction and Their Biological Activity Study
Authors: Mahato Birendra Nath , Krithiga T.
Published: September 2019

In this study, the mesoporous ZnO/AlSBA-15 (Si/Al=7) nanocomposite catalyst was prepared by using a combination of direct and impregnation procedure. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope coupled with energy-dispersive x-ray spectroscopy (SEM-EDS), N2 adsorption-desorption isotherm, Fourier transform infrared spectroscopy (FT-IR), and Temperature programmed reduction (TPR-H2). The XRD and N2 sorption results show the hexagonal mesoporous nature of catalyst with type IV adsorption isotherm. The surface area was calculated by the BET method and found to be 373 m2/g. From the TPR-H2 study, the reducibility temperature of ZnO found to be 966 K. Further, the Biginelli reaction is a promising multi-component reaction in organic synthetic chemistry as it approaches the green chemistry protocols and adducts are extensively used as drugs, intermediate and in medicine. Hence, the catalytic activity was tested in one pot Biginelii reaction for the synthesis of 3,4-dihydropyrimidin-2(1H)-one's derivative. The product yield was observed to be 96% at temperature 333 K, at the short response time of 4 h. The two adducts were examined by 1HNMR, 13CNMR, and FT-IR spectroscopy. Besides, the biological activity of adduct (A) C15H18N2O5 was explored by gram-positive bacteria (Staphylococcus aureus) and gram-negative microorganisms (E. coli). The adduct (A) C15H18N2O5 shows a clear inhibition zone of 24 mm against E. Coli whereas Azithromycin shows an inhibition zone of 28 mm. Copyright © 2019 BCREC Group. All rights reserved
Observation of Increased Dispersion of Pt and Mobility of Oxygen in Pt/g-Al2O3 Catalyst with La Modification in CO Oxidation
Authors: Wandondaeng Thanawat , Autthanit Chaowat , Jongsomjit Bunjerd , Praserthdam Piyasan
Published: September 2019

The study focuses on an improvement of the catalytic activity via CO oxidation for Pt/g-Al2O3 catalyst by addition of La onto the support prior to impregnation with Pt metals. The molar ratios of La/Al were varied from 0.01 to 0.15. Based on temperature-programmed desorption (TPD) of CO2, La addition apparently resulted in increased basicity of the catalysts, which is related to increasing of oxygen mobility. However, when considered the Pt dispersion measured by CO chemisorption, it was found that Pt dispersion also increased with increasing the amount of La addition up to La/Al = 0.05. It is suggested that too high amount of La addition can inhibit the dispersion Pt due to surface coverage of La. It is worth noting that the catalytic activity toward CO oxidation essentially depends on both Pt dispersion and oxygen mobility and they can be superimposed on each other. Based on this study, the Pt/g-Al2O3 catalyst with La addition of La/Al molar ratio = 0.05 showed the highest activity due to its optimal Pt dispersion and oxygen mobility leading to its highest value of turnover frequency (TOF).
Isatin Aldazines Synthesis using A Proton Exchanged Algerian Montmorillonite Clay as Acid Eco-friendly Catalyst
Authors: Benlahreche Boumadiene , Taleb Assya , Lahrech Mokhtar B. , Hacini Salih
Published: September 2019

An efficient and easy procedure is developed for the synthesis of isatin aldazines or bis-Schiff bases of isatin, catalyzed by a proton exchanged Algerian montmorillonite clay (MMT-H+) as green catalyst. The products were obtained in two catalyzed steps under conventional heating in ethanol. Isatin-3-hydrazone obtained from the reaction of isatin with hydrazine monohydrate reacts in the second step with the appropriate aromatic aldehydes to give the desired products in good yields. The main advantages of using this protonated solid non-toxic catalyst in this synthesis are its availability and low cost, the simplicity of its use, the recycling possibilities without significant loss of its catalytic activity and its environmentally benign process.
Tuning the Morphology of Ag3PO4 Photocatalysts with an Elevated Concentration of KH2PO4
Authors: Afifah Khusnul , Andreas Roy , Hermawan Dadan , Sulaeman Uyi
Published: September 2019

Tuning the morphology of Ag3PO4 photocatalysts with an elevated concentration of KH2PO4 have been successfully conducted. This photocatalyst was prepared by starting material of AgNO3 and KH2PO4.  The KH2PO4 aqueous solution with five concentrations of 0.10 M, 0.15 M, 0.30 M, 0.45 M, and 0.60 M was reacted with AgNO3 aqueous solution. The products were characterized using X-ray Diffraction (XRD), UV-Vis Diffuse Reflectance Spectroscopy (DRS), and Scanning Electron Microscopy (SEM). The concentration of KH2PO4 significantly affected the morphology, size, and crystallinity of catalyst. The morphology of Ag3PO4 may be tuned with the synthesis using an elevated concentration of KH2PO4. The sample with the synthesis using 0.15 M of KH2PO4 exhibited the excellent photocatalytic activity. The high photocatalytic activity was caused by the small size of mixed morphology of sphere and tetrahedron, high crystallinity and defect sites.
Effects of Calcination Temperatures on The Catalytic Activities of Alumina Supported Cobalt and Chromium Catalysts
Authors: Mardwita Mardwita , Sri Yusmartini Eka , Wisudawati Nidya
Published: September 2019

Catalysts properties are important for catalytic reactions. The interaction between support and metal in a catalyst is resulted from catalyst preparation. In this study, gamma-alumina (Al2O3) supported cobalt (Co) and chromium (Cr) catalysts were prepared by impregnation method and calcined at two different temperatures, they are 400 °C for 4 hours and 800 °C for 4 hours. The resulted catalysts contained 10 wt.% of metal and denoted as Co/Al2O3(400), Co/Al2O33(800), Cr/Al2O3(400), and Cr/Al2O3(800) catalysts. The surface and state of the catalysts were examined by using x-ray diffraction (XRD), x-ray photoelectron spectrometer (XPS) and transmission electron microscopy (TEM). The XRD result reveals that strong interaction between Co and Al2O3 due to a formation of higher cobalt oxide. The XRD result further indicates aggregation and strong support metal interaction between Co and Al2O3 during calcination. On the other hand, TEM result showed that large Co particle was observed on Al2O3. The Cr/Al2O3 catalysts were characterized by using XPS. The XPS results showed that Cr/Al2O3(800) catalyst was dominated by Cr6+ species at binding energy 579.04 eV, indicating high dispersion of Cr on Al2O3. Moreover, Cr metal particle was not observed on XRD and TEM image. All the characterization results provide information that the impregnated metal on Al2O3 showed different properties. Co metal particle tends to be more oxidized and formed large particle, however it was not observed on Cr metal particle.
Ruthenium-doped Titania-pillared Clay for The Selective Catalytic Oxidation of Cyclohexene: Influence of Ru Loading
Authors: Dali Ahmed , Rekkab-Hammoumraoui Ilhem , El Korso Sanaa , Boudjema Souheyla , Choukchou-Braham Abderrahim
Published: September 2019

A series of ruthenium-based catalysts supported on acid-activated montmorillonite (PILC) and interspersed with titanium (Ru/Ti-PILCs) were prepared with various amounts of ruthenium. Their catalytic performances in the selective oxidation of cyclohexene, using tert-butylhydroperoxide (TBHP) as oxidant were checked. The clay structure modification by acid activation and impregnation of transition metals resulted in an enhanced Lewis and Bronsted acidities. The Ru/Ti-PILCs materials were characterized using X-ray diffraction (XRD), surface area and pore volume measurements, surface acidity followed by Fourier transform infrared (FTIR) spectroscopy, chemical analysis, and Scanning Electron Microscopy (SEM). It was found that all catalysts can selectively oxidize cyclohexene through allylic oxidation leading mainly to 2-cyclohexene-1-one (Enone) as the major product, and 2-cyclohexene-1-ol (Enol) as secondary product. With the 5 %Ru/Ti-PILC, it was possible to reach 59 % cyclohexene total conversion, and 87 % selectivity into 2-cyclohexene-1-one and 13 % selectivity into 2-cyclohexene-1-ol.
Carbon-containing Hydroxyapatite Obtained from Fish Bone as Low-cost Mesoporous Material for Methylene Blue Adsorption
Authors: Nurhadi Mukhamad , Kusumawardani Ratna , Wirhanuddin Wirhanuddin , Gunawan Rahmat , Nur Hadi
Published: September 2019

The carbon-containing hydroxyapatite has been synthesized using the fish bone obtained from East Kalimantan, Indonesia. The synthesis was conducted at varying calcination temperature (300-700 °C) and duration time (1-5 h). The carbon-containing hydroxyapatite were characterized by using Nitrogen adsorption-desorption, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Thermogravimetric analysis (TGA) and Differential thermal analysis (DTA). The carbon-containing hydroxyapatite nanoparticles consisted of the mesoporous structure with a specific surface area of 159 m2.g-1 and pore size of 44 Å. The carbon-containing hydroxyapatite nanoparticles were utilized as the adsorbent for the removal of methylene blue by varying the contact time, initial dye concentration, pH, adsorbent dosage and temperature. The maximum amount of adsorption capacity was 56.49 mg.g-1. The adsorption was well fitted with the Langmuir adsorption model (R2 ~ 0.998) and the pseudo-second-order model. This indicated that the dye molecules were adsorbed on the surface-active site of carbon-containing hydroxyapatite via chemical binding, forming an adsorbate monolayer. Hence, the adsorption capability corresponds to the physical properties such as the surface area and pore volume of hydroxyapatite because the larger surface area consists of higher binding sites for the adsorption. Thermodynamic parameters, including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS), indicated that the adsorption of methylene blue onto the carbon-containing hydroxyapatite nanoparticles was spontaneous. Thus, carbon-containing hydroxyapatite nanoparticles can be applied as a low-cost adsorbent for the treatment of industrial effluents that are contaminated with the methylene blue.
Calcium‐dependent methylation by PRMT1 promotes erythroid differentiation through the p38α MAPK pathway
Authors: Liu Mei‐Yin , Hua Wei‐Kai , Chiou Yi‐Ying , Chen Chi‐Ju , Yao Chao‐Ling , Lai Yi‐Ting , Lin Chao‐Hsiung , Lin Wey‐Jinq
Published: September 2019

Protein arginine methyltransferase 1 (PRMT1) stimulates erythroid differentiation, but the signaling events upstream are yet to be identified. Ca2+ plays crucial roles during erythroid differentiation. Here, we show that Ca2+ enhances methylation during induced erythroid differentiation and that Ca2+ directly upregulates the catalytic activity of recombinant PRMT1 by increasing Vmax toward the substrate heterogeneous nuclear ribonucleoprotein A2. We demonstrate that PRMT1 is essential and responsible for the effect of Ca2+ on differentiation. Depletion of Ca2+ suppresses PRMT1‐mediated activation of p38α and p38α‐stimulated differentiation. Furthermore, Ca2+ stimulates methylation of p38α by PRMT1. This study uncovers a novel regulatory mechanism for PRMT1 by Ca2+ and identifies the PRMT1/p38α axis as an intracellular mediator of Ca2+ signaling during erythroid differentiation.
Evaluation of interfraction setup variations for postmastectomy radiation therapy using EPID‐based in vivo dosimetry
Authors: Kang Shengwei , Li Jie , Ma Jiabao , Zhang Wei , Liao Xiongfei , Qing Hou , Tan Tingqiang , Xin Xin , Tang Bin , Piermattei Angelo , Orlandini Lucia Clara
Published: September 2019

Postmastectomy radiation therapy is technically difficult and can be considered one of the most complex techniques concerning patient setup reproducibility. Slight patient setup variations — particularly when high‐conformal treatment techniques are used — can adversely affect the accuracy of the delivered dose and the patient outcome. This research aims to investigate the inter‐fraction setup variations occurring in two different scenarios of clinical practice: at the reference and at the current patient setups, when an image‐guided system is used or not used, respectively. The results were used with the secondary aim of assessing the robustness of the patient setup procedure in use. Forty eight patients treated with volumetric modulated arc and intensity modulated therapies were included in this study. EPID‐based in vivo dosimetry (IVD) was performed at the reference setup concomitantly with the weekly cone beam computed tomography acquisition and during the daily current setup. Three indices were analyzed: the ratio between the reconstructed and planned isocenter doses, % and the mean value of from a transit dosimetry based on a two‐dimensional ‐analysis of the electronic portal images using 5% and 5 mm as dose difference and distance to agreement gamma criteria; they were considered in tolerance if was within 5%, % > 90% and  < 0.4. One thousand and sixteen EPID‐based IVD were analyzed and 6.3% resulted out of the tolerance level. Setup errors represented the main cause of this off tolerance with an occurrence rate of 72.2%. The percentage of results out of tolerance obtained at the current setup was three times greater (9.5% vs 3.1%) than the one obtained at the reference setup, indicating weaknesses in the setup procedure. This study highlights an EPID‐based IVD system's utility in the radiotherapy routine as part of the patient’s treatment quality controls and to optimize (or confirm) the performed setup procedures’ accuracy.
MRI quality control for low‐field MR‐IGRT systems: Lessons learned
Authors: Michael Gach H. , Curcuru Austen N. , Wittland Erin J. , Maraghechi Borna , Cai Bin , Mutic Sasa , Green Olga L.
Published: September 2019

Purpose

To present lessons learned from magnetic resonance imaging (MRI) quality control (QC) tests for low‐field MRI‐guided radiation therapy (MR‐IGRT) systems.

Methods

MRI QC programs were established for low‐field MRI‐60Co and MRI‐Linac systems. A retrospective analysis of MRI subsystem performance covered system commissioning, operations, maintenance, and quality control. Performance issues were classified into three groups: (a) Image noise and artifact; (b) Magnetic field homogeneity and linearity; and (c) System reliability and stability.

Results

Image noise and artifacts were attributed to room noise sources, unsatisfactory system cabling, and broken RF receiver coils. Gantry angle‐dependent magnetic field inhomogeneities were more prominent on the MRI‐Linac due to the high volume of steel shielding in the gantry. B0 inhomogeneities measured in a 24‐cm spherical phantom were <5 ppm for both MR‐IGRT systems after using MRI gradient offset (MRI‐GO) compensation on the MRI‐Linac. However, significant signal dephasing occurred on the MRI‐Linac while the gantry was rotating. Spatial integrity measurements were sensitive to gradient calibration and vulnerable to shimming. The most common causes of MR‐IGRT system interruptions were software disconnects between the MRI and radiation therapy delivery subsystems caused by patient table, gantry, and multi‐leaf collimator (MLC) faults. The standard deviation (SD) of the receiver coil signal‐to‐noise ratio was 1.83 for the MRI‐60Co and 1.53 for the MRI‐Linac. The SD of the deviation from the mean for the Larmor frequency was 1.41 ppm for the MRI‐60Co and 1.54 ppm for the MRI‐Linac. The SD of the deviation from the mean for the transmitter reference amplitude was 0.90% for the MRI‐60Co and 1.68% for the MRI‐Linac. High SDs in image stability data corresponded to reports of spike noise.

Conclusions

There are significant technological challenges associated with implementing and maintaining MR‐IGRT systems. Most of the performance issues were identified and resolved during commissioning.
Quantifying the accuracy of deformable image registration for cone‐beam computed tomography with a physical phantom
Authors: Wu Richard Y. , Liu Amy Y. , Williamson Tyler D. , Yang Jinzhong , Wisdom Paul G. , Zhu Xiaorong R. , Frank Steven J. , Fuller Clifton D. , Gunn Gary B. , Gao Song
Published: September 2019

Purpose

Kilo‐voltage cone‐beam computed tomography (CBCT) is widely used for patient alignment, contour propagation, and adaptive treatment planning in radiation therapy. In this study, we evaluated the accuracy of deformable image registration (DIR) for CBCT under various imaging protocols with different noise and patient dose levels.

Methods

A physical phantom previously developed to facilitate end‐to‐end testing of the DIR accuracy was used with Varian Velocity v4.0 software to evaluate the performance of image registration from CT to CT, CBCT to CT, and CBCT to CBCT. The phantom is acrylic and includes several inserts that simulate different tissue shapes and properties. Deformations and anatomic changes were simulated by changing the rotations of both the phantom and the inserts. CT images (from a head and neck protocol) and CBCT images (from pelvis, head and “Image Gently” protocols) were obtained with different image noise and dose levels. Large inserts were filled with Mobil DTE oil to simulate soft tissue, and small inserts were filled with bone materials. All inserts were contoured before the DIR process to provide a ground truth contour size and shape for comparison. After the DIR process, all deformed contours were compared with the originals using Dice similarity coefficient (DSC) and mean distance to agreement (MDA). Both large and small volume of interests (VOIs) for DIR volume selection were tested by simulating a DIR process that included whole patient image volume and clinical target volumes (CTV) only (for CTVs propagation).

Results

For cross‐modality DIR registration (CT to CBCT), the DSC were >0.8 and the MDA were <3 mm for CBCT pelvis, and CBCT head protocols. For CBCT to CBCT and CT to CT, the DIR accuracy was improved relative to the cross‐modality tests. For smaller VOIs, the DSC were >0.8 and MDA <2 mm for all modalities.

Conclusions

The accuracy of DIR depends on the quality of the CBCT image at different dose and noise levels.
Palladium‐Catalyzed Synthesis of 6H‐Dibenzo[c,h]chromenes and 5,6‐Dihydrobenzo[c]phenanthridines: Application to the Synthesis of Dibenzo[c,h]chromene‐6‐ones, Benzo[c]phenanthridines, and Arnottin I
Authors: Pramanik Subhendu , Jash Moumita , Mondal Debasmita , Chowdhury Chinmay
Published: September 2019

6H‐Dibenzo[c,h]chromenes and 5,6‐dihydrobenzo[c]phenanthridines have been synthesized via Palladium (II)‐catalyzed domino reactions of acetylenic substrates involving intramolecular trans‐oxo/amino palladation onto the triple bond followed by nucleophilic addition of the intermediate to a tethered cyano/aldehyde. The scope of this reaction was extended through one step conversion of some of the products to 6H‐dibenzo[c,h]chromen‐6‐ones and benzo[c]phenanthridines. Utilization of this methodology led to a formal total synthesis of the natural product Arnottin I.

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Efficient Synthesis of 3,6‐Dihydro‐2H‐pyrans via [3+2+1] Annulation Based on the Heteroatom‐free Tri‐atom Donor
Authors: Li Hui , Liu Haiping , Liu Yufeng , Cao Zhongzhong , Su Miaodong , Fu Meiqiang , Luo Weiping , Liu Qiang , Guo Cancheng
Published: September 2019

A new [3+2+1] annulation strategy based on the heteroatom‐free tri‐atom donor to synthesize 3,6‐dihydro‐2H‐pyrans has been developed. In this method, 2‐arylpropylene served as tri‐atom donor to contribute three carbon atoms, the heteroatom was provided by aldehyde, and DMSO served as one carbon donor and solvent. This annulation reaction gave 3,6‐dihydro‐2H‐pyrans in moderate to good yields. Based on the control experiments, a possible mechanism was proposed.

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Copper‐Catalyzed Alkynylation of C(sp3)−H Bonds in N‐Fluoro‐sulfonamides
Authors: Yin Zhiping , Zhang Youcan , Zhang Shuo , Wu Xiao‐Feng
Published: September 2019

Herein, we developed a copper‐catalyzed approach for the remote C(sp3)−H alkynylation of N‐fluoro‐sulfonamides. With Cu(OTf)2 as the catalyst, the carbon radical which generated from nitrogen radical‐mediated 1,5‐hydrogen atom transfer, go through an addition/fragmentation reaction with various acetylene sulfones. A variety of internal alkynes were synthesized in high yield and regioselectivity. Notably, celecoxib‐derived substrate can also gave the corresponding functionalized product in good yield under the standard conditions.

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