Excellence in Research and Innovation for Humanity

International Science Index

Commenced in January 1999 Frequency: Monthly Edition: International Abstract Count: 42820

Chemical and Molecular Engineering

1821
74787
Ultrasensitive Detection and Discrimination of Cancer-Related Single Nucleotide Polymorphisms Using Poly-Enzyme Polymer Bead Amplification
Abstract:
The ability of ultrasensitive detection of specific genes and discrimination of single nucleotide polymorphisms is important for clinical diagnosis and biomedical research. Herein, we report the development of a new ultrasensitive approach for label-free DNA detection using magnetic nanoparticle (MNP) assisted rapid target capture/separation in combination with signal amplification using poly-enzyme tagged polymer nanobead. The sensor uses an MNP linked capture DNA and a biotin modified signal DNA to sandwich bind the target followed by ligation to provide high single-nucleotide polymorphism discrimination. Only the presence of a perfect match target DNA yields a covalent linkage between the capture and signal DNAs for subsequent conjugation of a neutravidin-modified horseradish peroxidase (HRP) enzyme through the strong biotin-nuetravidin interaction. This converts each captured DNA target into an HRP which can convert millions of copies of a non-fluorescent substrate (amplex red) to a highly fluorescent product (resorufin), for great signal amplification. The use of polymer nanobead each tagged with thousands of copies of HRPs as the signal amplifier greatly improves the signal amplification power, leading to greatly improved sensitivity. We show our biosensing approach can specifically detect an unlabeled DNA target down to 10 aM with a wide dynamic range of 5 orders of magnitude (from 0.001 fM to 100.0 fM). Furthermore, our approach has a high discrimination between a perfectly matched gene and its cancer-related single-base mismatch targets (SNPs): It can positively detect the perfect match DNA target even in the presence of 100 fold excess of co-existing SNPs. This sensing approach also works robustly in clinical relevant media (e.g. 10% human serum) and gives almost the same SNP discrimination ratio as that in clean buffers. Therefore, this ultrasensitive SNP biosensor appears to be well-suited for potential diagnostic applications of genetic diseases.
1820
74761
Amine Hardeners with Carbon Nanotubes Dispersing Ability for Epoxy Coating Systems
Abstract:
An addition of carbon nanotubes (CNT) can simultaneously improve many features of epoxy coatings, i.e. electrical, mechanical, functional and thermal. Unfortunately, this nanofiller negatively affects visual properties of the coatings, such as transparency and gloss. The main reason for the low visual performance of CNT-modified epoxy coatings is the lack of compatibility between CNT and popular amine curing agents, although epoxy resins based on bisphenol A are indisputable good CNT dispersants. This is a serious obstacle in utilization of the coatings in advanced applications, demanding both high transparency and electrical conductivity. The aim of performed investigations was to find amine curing agents exhibiting affinity for CNT, and ensuring good performance of epoxy coatings with them. Commercially available CNT was dispersed in epoxy resin, as well as in different aliphatic, cycloaliphatic and aromatic amines, using one of two dispergation methods: ultrasonic or mechanical. The CNT dispersions were subsequently used in the preparation of epoxy coating compositions and coatings on a transparent substrate. It was found that amine derivative of bio-based cardanol, as well as modified o-tolylbiguanide exhibit significant CNT, dispersing properties, resulting in improved transparent/electroconductive performance of epoxy coatings. In one of prepared coating systems just 0.025 wt.% (250 ppm) of CNT was enough to obtain coatings with semi conductive properties, 83% of transparency as well as perfect chemical resistance to methyl-ethyl ketone and improved thermal stability. Additionally, a theory of the influence of amine chemical structure on CNT dispersing properties was proposed.
1819
74728
Thin-Layer Drying Characteristics and Modelling of Instant Coffee Solution
Abstract:
The thin-layer drying characteristics of instant coffee solution were investigated in a laboratory tunnel dryer. Drying experiments were carried out at three temperatures (80, 100 and 120 °C) and at an air velocity of 1.2 m/s. During the experimental runs, as soon as the instant coffee solution sample is exposed to the drying air a semi-solid layer is observed on the surface of the sample. As the evaporation progresses, the layer grows thicker showing solid-like characteristics as the liquid is evaporated, thus resulting in an instant coffee solution crystallised over the entire sample holder. The formation of this layer becomes an additional resistance to mass transfer during evaporation. The drying experimental data obtained are fitted to six thin-layer drying models using the non-linear least squares regression analysis. The acceptability of the thin-layer drying model has been based on a value for the correlation coefficient that should be close to one, and low values for RMSE and x². According to this evaluation, the most suitable model in describing drying process of thin-layer instant coffee solution is the Page model. Further, the effective moisture diffusivity and the activation energy were computed employing the drying experimental data. The effective moisture diffusivity values varied from 1.6133 × 10-9 to 1.6224 × 10-9 m2/s over the temperature range studied and the activation energy was estimated to be 162.62 J/mol.
1818
74617
Anti-Biofilm Activity of Citrate Intercalated Layered Double Hydroxide against Selected Biofilm Forming Uropathogens
Abstract:
Chronic catheter-associated urinary tract infections (CAUTI) are mainly due to biofilm formation from uropathogens. Citrate is one of promising anti-biofilm forming agents used to prevent biofilm formation as a catheter lock solution and as an oral intake. However, maintaining concentration of citrate for a long period of time will be beneficial in order to design a prolonged treatment. This study focused to determine the inhibitory effect of citrate intercalated Mg and Al layered double hydroxides (citrate-LDH) as a slow releasing agent against P. aeruginosa, S. aureus, and E. faecalis. Biofilms of mono- and co-cultures of P. aeruginosa, S. aureus, and E. faecalis were developed in the presence of Brain Heart Infusion (BHI) broth. The influence of citrate-LDH against planktonic bacteria was investigated using agar well diffusion method and the minimum inhibitory concentration (MIC) was determined using pore plate method. In order to determine the anti-biofilm efficacy of laboratory synthesized citrate-LDH, the biofilms were grown in a 96-well microtiter plate biofilm model. The minimum biofilm inhibitory concentration (MBIC) and the minimum killing time for 48 hours matured biofilms were determined by MTT (3-[4, 5- dimethylthiazole-2-yl]-2, 5- diphenyltetrazolium bromide) viability assay. Further, Scanning Electron Microscopy (SEM) was performed to image the pre- and post-exposure architecture of biofilms. Citrate-LDH exhibited a significant inhibition against P. aeruginosa, S. aureus, and E. faecalis compared to the positive control. For all tested strains, the MIC value of Citrate-LDH was 1×10-5 g/mL. All bacterial species exhibited sensitivity for citrate-LDH. For all tested strains, the MBIC value of Citrate-LDH was 0.01 g/mL for a 70% reduction while 0.10 g/mL for a 98% reduction. The minimum killing time was 6 hours for MBIC70, and it was constant for all 48 h confirming the slow releasing ability of citrate-LDH. The SEM images confirmed the biofilm inhibitory effect of citrate-LDH as it has reduced the population of microorganism and extracellular polysaccharide matrix considerably compared to the control. Citrate-LDH has a sustainable biofilm reducible activity against tested uropathogens i.e. P. aeruginosa, S. aureus, and E. faecalis. Further, citrate-LDH will be a potential future anti-biofilm agent in treating chronic catheter associated urinary tract infections. However extensive studies are required with other important biofilm forming uropathogens in order to confirm the above findings.
1817
74549
Synthesis of Cellulose Nanocrystals from Oil Palm Empty Fruit Bunch by Using Phosphotungstic Acid
Abstract:
Oil palm empty fruit bunch (OPEFB), an abundant agro-waste in Indonesia, is being studied as raw material of Cellulose Nanocrystals (CNC) synthesis. Instead of conventional acid mineral, phosphotungstic acid (H₃PW₁₂O₄₀, HPW) was used to hydrolyze cellulose due to recycling ability and easy handling. Before hydrolysis process, dried EFB was treated by 4% NaOH solution at 90oC for 2 hours and then bleached using 2% NaClO₂ solution at 80oC for 3 hours to remove hemicellulose and lignin. Hydrolysis reaction parameters such as temperature, acid concentration, and reaction time were optimized with fixed solid-liquid ratio of 1:40. Response surface method was used for experimental design to determine the optimum condition of each parameter. HPW was extracted from the mixed solution and recycled with diethyl ether. CNC was separated from the solution by centrifuging and washing with distilled water and ethanol to remove degraded sugars and unreacted celluloses. In this study, pulp from dried EFB produced 44.8% yield of CNC. Dynamic Light Scattering (DLS) analysis showed that most of CNC equivalent diameter was 140 nm. Crystallinity index was observed at 73.3% using X-ray Diffraction (XRD) analysis. Thus, a green established process for the preparation of CNC was achieved.
1816
74519
Continuous Processing Approaches for Tunable Asymmetric Photochemical Synthesis
Abstract:
Enabling technologies such as continuous processing (CP) approaches can provide the tools needed to control and manipulate reactivities and transform chemical reactions into micro-controlled in-flow processes. Traditional synthetic approaches can be radically transformed by the application of CP, facilitating the pairing of chemical methodologies with technologies from other disciplines. CP supports sustainable processes that controllably generate reaction specificity utilizing supramolecular interactions. Continuous photochemical processing is an emerging field of investigation. The use of light to drive chemical reactivity is not novel, but the controlled use of specific and tunable wavelengths of light to selectively generate molecular structure under continuous processing conditions is an innovative approach towards chemical synthesis. This investigation focuses on the use of circularly polarized (cp) light as a sustainable catalyst for the CP generation of asymmetric molecules. Chiral photolysis has already been achieved under batch, solid-phase conditions: using synchrotron-sourced cp light, asymmetric photolytic selectivities of up to 4.2% enantiomeric excess (e.e.) have been reported. In order to determine the optimal wavelengths to use for irradiation with cp light for any given molecular building block, CD and anisotropy spectra for each building block of interest have been generated in two different solvents (water, hexafluoroisopropanol) across a range of wavelengths (130-400 nm). These spectra are being used to support a series of CP experiments using cp light to generate enantioselectivity.
1815
74287
Dry Matter, Moisture, Ash and Crude Fibre Content in Distinct Segments of 'Durian Kampung' Husk
Abstract:
An environmental friendly approach for disposal of voluminous durian husk waste could be implemented by substituting them into various valuable commodities, such as healthcare and biofuel products. Thus, the study of composition value in each segment of durian husk was very crucial to determine the suitable proportions of nutrients need to be added and mixed in the product. A total of 12 ‘Durian Kampung’ fruits from Sg Ruan, Pahang were selected and each fruit husk was divided into four segments and labeled as P-L (thin neck area of white inner husk), P-B (thick bottom area of white inner husk), H (green and thorny outer husk) and W (whole combination of P-B and H). Four experiments have been carried out to determine the dry matter, moisture, ash and crude fibre content. The results show that H segment has the highest dry matter content (30.47%), while P-B segment has the highest percentage of moisture (81.83%) and ash (6.95%) content. It was calculated that ash content of P-B segment has a higher rate of moisture level which causes the ash content to increase about 2.89% from the P-L segment. These data had proven that each segment of durian husk has a significant difference in term of composition value which might be a useful information to fully utilize every part of the durian husk in the future.
1814
74220
Antioxidant Extraction from Indonesian Crude Palm Oil and Its Antioxidation Activity
Abstract:
Crude palm oil (CPO) is a vegetable oil that came from a palm tree bunch. Palm oil tree was known as highest vegetable oil yield. It was grown across Equatorial County, especially in Malaysia and Indonesia. The greenish red color on CPO was came from carotenoid antioxidant, which could be extracted and use separately as functional food and other purposes as antioxidant source. Another antioxidant that also found in CPO is tocopherol. The aim of the research work is to find antioxidant activity on CPO comparing to the synthetic antioxidant that available in a market. On this research work, antioxidant was extracted by using a mixture of acetone and n. hexane, while activity of the antioxidant extract was determine by DPPH method. The extracted matter was shown that their antioxidant activity was about 45% compare to pure tocopherol and beta carotene.
1813
74206
Upgrading of Bio-Oil by Bio-Pd Catalyst
Abstract:
This paper reports the application of a bacteria-supported palladium catalyst to the hydrodeoxygenation (HDO) of pyrolysis bio-oil, towards producing an upgraded transport fuel. Biofuels are key to the timely replacement of fossil fuels in order to mitigate the emissions of greenhouse gases and depletion of non-renewable resources. The process is an essential step in the upgrading of bio-oils derived from industrial by-products such as agricultural and forestry wastes, the crude oil from pyrolysis containing a large amount of oxygen that requires to be removed in order to create a fuel resembling fossil-derived hydrocarbons. The bacteria supported catalyst manufacture is a means of utilizing recycled metals and second life bacteria, and the metal can also be easily recovered from the spent catalysts after use. Comparisons are made between bio-Pd, and a conventional activated carbon supported Pd/C catalyst. Bio-oil was produced by fast pyrolysis of beechwood at 500 C at a residence time below 2 seconds, provided by Aston University. 5 wt % BioPd/C was prepared under reducing conditions, exposing cells of E. coli MC4100 to a solution of sodium tetrachloropalladate (Na2PdCl4), followed by rinsing, drying and grinding to form a powder. Pd/C was procured from Sigma-Aldrich. The HDO experiments were carried out in a 100 mL Parr batch autoclave using ~20g bio-crude oil and 0.6 g bio-Pd/C catalyst. Experimental variables investigated for optimization included temperature (160-350C) and reaction times (up to 5 h) at a hydrogen pressure of 100 bar. Most of the experiments resulted in an aqueous phase (~40%) and an organic phase (~50-60%) as well as gas phase (
1812
74197
Synthesis of Rare-Earth Pyrazolate Compounds
Abstract:
Since coordination behavior of pyrazoles and pyrazolate ions are widely versatile towards a great range of metals such as d-block, f-block as well as main group elements; they attract interest as ligands for preparing compounds. A variety of rare-earth pyrazolate complexes have been synthesized by redox transmetalation/protolysis (RTP) previously, therefore, a variety of rare-earth pyrazolate complexes using two pyrazoles, 3,5-dimethylpyrazole (Me₂pzH) and 3,5-di-tert -butylpyrazolate (t-Bu₂pzH), in which the structures span the whole La-Lu array beside Sc and Y has been synthesized by RTP reaction. There have been further developments in this study: Synthesizing structure of [Tb(Me₂pz)₃(thf)]₂ which is isomorphous with those of the previously reported [Dy(Me₂pz)₃(thf)]₂ and [Lu(Me₂pz)₃(thf)]₂ analogous that has two µ-1(N):2(Nʹ)-Me2pz ligands (the most common pyrazolate ligation for non-rare-earth complexes). Previously most of the reported compounds using t-Bu2pzH were monomeric compounds however the lanthanum derivative [La(Me₂pz)₃thf₂] ,which has been reported previously without crystal structure, has now been structurally characterized, along with cerium and lutetium analogue. Also a polymeric structure with samarium has now been synthesized which the neodymium analogue has been reported previously and comparing these polymeric structures can support the idea that the geometry of Sm(tBu₂pz)₃ affect the coordination of the solvent. Also, by using 1,2-dimethoxyethane (DME) instead of tetrahydrofuran (THF) new [Er(tBu₂pz)₃ (dme)₂] has now been reported.
1811
74154
Catalytic Soot Gasification in Single and Mixed Atmospheres of CO2 and H2O in the Presence of CO and H2
Abstract:
LiFeO2 nano-powders were prepared via solution combustion synthesis (SCS) method and were used as carbon gasification catalyst in a reduced atmosphere. The gasification of soot with CO2 and H2O in the presence of CO and H2 (syngas atmosphere) were also investigated under atmospheric conditions using a fixed-bed micro-reactor placed in an electric, PID-regulated oven. The catalytic bed was composed of 150 mg of inert silica, 45 mg of carbon (Printex-U) and 5 mg of catalyst. The bed was prepared by ball milling the mixture at 240 rpm for 15 min to get an intimate contact between the catalyst and soot. A Gas Hourly Space Velocity (GHSV) of 38.000 h-1 was used for the tests campaign. The furnace was heated up to the desired temperature, a flow of 120 mL/min was sent into the system and at the same time the concentrations of CO, CO2 and H2 were recorded at the reactor outlet using an EMERSON X-STREAM XEGP analyzer. Catalytic and non-catalytic soot gasification reactions were studied in a temperature range of 120°C – 850°C with a heating rate of 5 °C/min (non-isothermal case) and at 650°C for 40 minutes (isothermal case). Experimental results show that the gasification of soot with H2O and CO2 are inhibited by the H2 and CO, respectively. The soot conversion at 650°C decreases from 70.2% to 31.6% when the CO is present in the feed. Besides, the soot conversion was 73.1% and 48.6% for H2O-soot and H2O-H2-soot gasification reactions, respectively. Also, it was observed that the carbon gasification in mixed atmosphere, i.e., when simultaneous carbon gasification with CO2 and steam take place, with H2 and CO as co-reagents; the gasification reaction is strongly inhibited by CO and H2, as well has been observed in single atmospheres for the isothermal and non-isothermal reactions. Further, it has been observed that when CO2 and H2O react with carbon at the same time, there is a passive cooperation of steam and carbon dioxide in the gasification reaction, this means that the two gases operate on separate active sites without influencing each other. Finally, despite the extreme reduced operating conditions, it has been demonstrated that the 32.9% of the initial carbon was gasified using LiFeO2-catalyst, while in the non-catalytic case only 8% of the soot was gasified at 650°C.
1810
74140
Green Synthesis of Magnetic, Silica Nanocomposite and Its Adsorptive Performance against Organochlorine Pesticides
Abstract:
Green synthesis of nanomaterials has received increasing attention as an eco-friendly technology in materials science. Here, we have used two types of extractions from green tea leaf (i.e. total extraction and tannin extraction) as reducing agents for a rapid, simple and one step synthesis method of mesoporous silica nanoparticles (MSNPs)/iron oxide (Fe3O4) nanocomposite based on deposition of Fe3O4 onto MSNPs. MSNPs/Fe3O4 nanocomposite were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray, vibrating sample magnetometer, N2 adsorption, and high-resolution transmission electron microscopy. The average mesoporous silica particle diameter was found to be around 30 nm with high surface area (818 m2/gm). MSNPs/Fe3O4 nanocomposite was used for removing lindane pesticide (an environmental hazard material) from aqueous solutions. Fourier transform infrared, UV-vis, High-performance liquid chromatography and gas chromatography techniques were used to confirm the high ability of MSNPs/Fe3O4 nanocomposite for sensing and capture of lindane molecules with high sorption capacity (more than 89%) that could develop a new eco-friendly strategy for detection and removing of pesticide and as a promising material for water treatment application.
1809
74096
The Effect of Solution pH of Chitosan on Antimicrobial Properties of Nylon 6,6 Fabrics
Abstract:
The present study aims at studying the effect of solution pH of chitosan on antimicrobial properties of nylon 6,6 fabrics. Nylon 6,6 fabrics were crosslinked with chitosans at different chitosan solutions having different pH levels. The pH of the chitosan solutions was adjusted to pH1, pH3 and pH5 levels by controlling the addition of diluted acetic acid. Also, an additional chitosan solution was prepared with the addition of sodium carbonate to raise the pH to pH8 level to see the effects of basic conditions on antimicrobial activity. After treating the fabric samples with each solution, AATCC Test Method 100 was followed to evaluate the antimicrobial activity using Staphylococcus aureus ATCC 6538 test inoculum by calculating the percentage reduction of bacteria. In acidic media (ph < 6.5), all treated samples showed antimicrobial activity because of its poor solubility above 6.5. No correlation was found between pH levels and antimicrobial activity in acidic media. In basic media (ph ˃ 7), the samples have not shown any antimicrobial activity since amino groups of chitosan became protonated and did not allow the formation of electrostatic interactions involving the NH3+groups of chitosan.
1808
73972
Influence Study of the Molar Ratio between Solvent and Initiator on the Reaction Rate of Polyether Polyols Synthesis
Abstract:
Flame-retardants are incorporated in different materials in order to reduce the risk of fire, either by providing increased resistance to ignition, or by acting to slow down combustion and thereby delay the spread of flames. In this work, polyether polyols with fire retardant properties were synthesized due to their wide application in the polyurethanes formulation. The combustion of polyurethanes is primarily dependent on the thermal properties of the polymer, the presence of impurities and formulation residue in the polymer as well as the supply of oxygen. There are many types of flame retardants, most of them are phosphorous compounds of different nature and functionality. The addition of these compounds is the most common method for the incorporation of flame retardant properties. The employment of glycerol phosphate sodium salt as initiator for the polyol synthesis allows obtaining polyols with phosphate groups in their structure. However, some of the critical points of the use of glycerol phosphate salt are: the lower reactivity of the salt and the necessity of a solvent (dimethyl sulfoxide, DMSO). Thus, the main aim in the present work was to determine the amount of the solvent needed to get a good solubility of the initiator salt. Although the anionic polymerization mechanism of polyether formation is well known, it seems convenient to clarify the role that DMSO plays at the starting point of the polymerization process. Regarding the fact that the catalyst deprotonizes the hydroxyl groups of the initiator and as a result of this, two water molecules and glycerol phosphate alkoxide are formed. This alkoxide, together with DMSO, has to form a homogeneous mixture where the initiator (solid) and the propylene oxide (PO) are soluble enough to mutually interact. The addition rate of PO increased when the solvent/initiator ratios studied were increased, observing that it also made the initiation step shorter. Furthermore, the molecular weight of the polyol decreased when higher solvent/initiator ratios were used, what revealed that more amount of salt was activated, initiating more chains of lower length but allowing to react more phosphate molecules and to increase the percentage of phosphorous in the final polyol. However, the final phosphorous content was lower than the theoretical one because only a percentage of salt was activated. On the other hand, glycerol phosphate disodium salt was still partially insoluble in DMSO studied proportions, thus, the recovery and reuse of this part of the salt for the synthesis of new flame retardant polyols was evaluated. In the recovered salt case, the rate of addition of PO remained the same than in the commercial salt but a shorter induction period was observed, this is because the recovered salt presents a higher amount of deprotonated hydroxyl groups. Besides, according to molecular weight, polydispersity index, FT-IR spectrum and thermal stability, there were no differences between both synthesized polyols. Thus, it is possible to use the recovered glycerol phosphate disodium salt in the same way that the commercial one.
1807
73963
Optimization of Surface Coating on Magnetic Nanoparticles for Biomedical Applications
Abstract:
Owing to their unique properties, magnetic nanoparticles have been used as diagnostic and therapeutic agents for biomedical applications. Highly monodispersed magnetic nanoparticles with controlled particle size and surface coating have been successfully synthesized as a model system to investigate the effect of surface coating on the T2 relaxivity and specific absorption rate (SAR) under an alternating magnetic field, respectively. Amongst, by using mPEG-g-PEI to solubilize oleic-acid capped 6 nm magnetic nanoparticles, the T2 relaxivity could be significantly increased by up to 4-fold as compared to PEG coated nanoparticles. Moreover, it largely enhances the cell uptake with a T2 relaxivity of 92.6 mM-1s-1 for in vitro cell MRI. As for hyperthermia agent, SAR value increase with the decreased thickness of PEG surface coating. By elaborate optimization of surface coating and particle size, a significant increase of SAR (up to 74%) could be achieved with a minimal variation on the saturation magnetization (
1806
73865
Chemical Treatment of Wastewater through Biosorption for the Removal of Toxic Metals
Abstract:
Water/wastewater often contains heavy/toxic metals, such as lead, copper, zinc and arsenic as well as harmful elements, such as antimony, selenium and fluoride. It may also contains radioactive elements, such as cesium and strontium. If they are not removed from water/wastewater then the environment and human health can be negatively impacted. Extensive research has been carried out to remove such harmful metals/elements from water/wastewater through biosorption using biomaterials (bioadsorbents). This presentation will give an overview of the research on preparation of bioadsorbents from biomass wastes and their use for the removal of harmful metals/elements from aqueous media.
1805
73864
Biosorption of Gold from Chloride Media in a Simultaneous Adsorption-Reduction Process
Abstract:
Conventional hydrometallurgical processing of metals involves the use of large quantities of toxic chemicals. Realizing a need to develop sustainable technologies, extensive research studies are being carried out to recover and recycle base, precious and rare earth metals from their pregnant leach solutions (PLS) using green chemicals/biomaterials prepared from biomass wastes derived from agriculture, marine and forest resources. Our innovative research showed that bio-adsorbents prepared from such biomass wastes can effectively adsorb precious metals, especially gold after conversion of their functional groups in a very simple process. The highly effective ‘Adsorption-coupled-Reduction’ phenomenon witnessed appears promising for the potential use of this gold biosorption process in the mining industry. Proper management and effective use of biomass wastes as value added green chemicals will not only reduce the volume of wastes being generated every day in our society, but will also have a high-end value to the mining and mineral processing industries as those biomaterials would be cheap, but very selective for gold recovery/recycling from low grade ore, leach residue or e-wastes.
1804
73822
Investigation of Mutagenicity and DNA Binding Properties of Metal-Free and Metallophthalocyanines Containing α-Napththolbenzein Groups on the Peripheral Positions
Abstract:
In this work, phthalocyanine compounds containing α-naphtholbenzeinunits have been synthesized. Mutagenicity and DNA binding properties of the compounds were investigated by Salmonella/Microsome Assay and spectrophotometer. According to the results of the preliminary range finding tests, the compounds gave no toxic effect to all tester strain S. typhimurium TA98 and TA100 at doses of 500, 1100, 350, 500 and 750 µg/plate in the presence and absence of S9, respectively. This study showed that all compounds exhibited efficient DNA-binding activity. In conclusion, these non-toxic compounds may be used as effective DNA dyes for molecular biology studies.
1803
73729
Model and Algorithms for the Design of Specific Molecular Cages
Abstract:
This article presents an algorithmic approach to predict cages of organic molecules, i.e., 3-dimensional semi-molecular architectures possessing a defined inner-space able to trap a target molecule called substrate. The cages of organic molecules are structural solutions for molecular organic cages. Many works propose to generate molecular organic cages obtained from symmetric structures, which have good complexity, but they are also not specific because they do not take precise targets into account. The proposed method allows generating a cage of organic molecules specific to a given substrate. In order to guarantee the specificity of the molecular cage for the target substrate, an intermediate structure, which is an expansion of the envelope of the target substrate, is used. Then, a cage is generated from this envelope replacing some set of vertices by molecular cycles. For this, chemical theory, such as the VSEPR theory, and computational geometry methods are used.
1802
73617
Recovery of Molybdenum as Molybdenum Trioxide from Mo-Co Spent Catalyst Using Cyphos IL 104
Abstract:
Molybdenum is widely used in thermocouples, anticathode of X-ray tubes and in the production of alloys of steel. Molybdenum compounds are extensively used as a catalyst in petroleum refining industries for hydrodesulphurization. Activity of the catalysts decreases gradually with time and are dumped as hazardous waste due to contamination with toxic materials during the process. These spent catalysts can serve as a secondary source for metal recovery and help to sort out environmental and economical issues. In the present study, extraction and separation of molybdenum from a Mo-Co spent catalyst leach liquor containing 0.870 g L⁻¹ Mo, 0.341 g L⁻¹ Co, 0.422 ×10⁻¹ g L⁻¹ Fe and 0.508 g L⁻¹ Al in 3 mol L⁻¹ HCl has been investigated using solvent extraction technique. The extracted molybdenum has been finally recovered as molybdenum trioxide. Leaching conditions used were 3 mol L⁻¹ HCl, 90°C temperature, solid to liquid ratio (w/v) of 1.25% and reaction time of 60 minutes. 96.45% molybdenum was leached under these conditions. For the extraction of molybdenum from leach liquor, Cyphos IL 104 [trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate] in toluene was used as an extractant. Around 91% molybdenum was extracted with 0.02 mol L⁻¹ Cyphos IL 104 and 75% of molybdenum was stripped from the loaded organic phase with 2 mol L⁻¹ HNO₃ at A/O=1/1. McCabe Thiele diagrams were drawn to determine the number of stages required for the extraction and stripping of molybdenum. According to McCabe Thiele plots, two stages are required for both extraction and stripping of molybdenum at A/O=1/1 which were also confirmed by counter current simulation studies. Around 98% molybdenum was extracted in two counter current extraction stages with no co-extraction of cobalt and aluminium. Iron was removed from the loaded organic phase by scrubbing with 0.01 mol L⁻¹ HCl. Quantitative recovery (98%) of molybdenum is achieved in two counter-current stripping stages at A/O=1/1. Trioxide of molybdenum was obtained from strip solution and was characterized by XRD, FE-SEM and EDX techniques. Molybdenum trioxide due to its distinctive electrochromic, thermochromic and photochromic properties is used as a smart material for sensors, lubricants, and Li-ion batteries. Molybdenum trioxide finds application in various processes such as methanol oxidation, metathesis, propane oxidation and in hydrodesulphurization. It can also be used as a precursor for the synthesis of MoS₂ and MoSe₂.
1801
73548
Assessment of Drug Delivery Systems from Molecular Dynamic Perspective
Abstract:
The intensive labor and high cost of developing new vehicles for controlled drug delivery highlights the need for a change in their discovery procedure. Computational models can be utilized to accelerate experimental steps and control the experiments high cost. In this study, to better understand the interaction of anti-cancer drug and the nanocarrier with the cell membrane, we have done molecular dynamics simulation (MDS) using NAMD. Paclitaxel and dipalmitoylphosphatidylcholine (DPPC) have been opted for the drug molecule and as a natural phospholipid nanocarrier, respectively. The center of mass (COM) between molecules and the van der Waals interaction energy close to the cell membrane have been investigated. Moreover, the simulation results of the paclitaxel interaction with the cell membrane and the interaction of DPPC as a nanocarrier loaded by the drug with the cell membrane have been compared. Analysis of molecular dynamics showed that not only the energy between the nanocarrier and the cell membrane is low, but also the center of mass amount decreases in the nanocarrier and the cell membrane system during the interaction; therefore they demonstrate remarkably better interaction in comparison to the individual drug with the cell membrane.
1800
73491
Surpassing Antibiotic Resistance through Synergistic Effects of Polyethyleneimine-Silver Nanoparticle Complex Coated Mesoporous Silica Trio-Nanoconstructs
Abstract:
Antibiotic resistance in bacteria has become an emergency situation clinically. To improve the efficacy of antibiotics in resistant strains, advancement of nanoparticles is inevitable than ever. Herewith, we demonstrate a design by immobilizing tetracycline (TET) in copper substituted mesoporous silica nanoparticles (Cu-MSNs) through a pH-sensitive coordination link, enabling its release in the acidic environment. Subsequently, MSNs are coated with silver nanoparticles stabilized polyethyleneimine (PEI-SNP) to act against drug-resistant (MDR) bacterial strains. Silver ions released from SNP are capable of sensitizing the resistant strains and facilitate the generation of free radicals capable of damaging the cell components. In addition, copper ions in the framework are also capable of generating free radicals through Fenton-like reaction. Furthermore, the nanoparticles are well-characterized physically, and various antibacterial efficacious tests against isolated multidrug resistant bacterial strain were highly commendable. However, this formulation has no significant toxic effect on normal mammalian fibroblast cells accounting its high biocompatibility. These MSN trio-hybrids, i.e., SNP, tetracycline, and copper ions result in synergistic effects, and their advancement could bypass resistance and allow synergism for effective treatment of antibiotic clinically.
1799
73466
Synthesis, Spectroscopic and Thermal Studies of Copper(I) Chlorido Complexes of Thioureas
Abstract:
The study of the coordination behavior of thiones is of considerable interest due to the similarity of their binding sites to those in living systems. The complexation of thiones towards Copper(I) has also received considerable attraction in view of their variable bonding modes, structural diversity and promising biological implications. Copper (I) complexes of thioureas of the general formula: CuLCl, CuL2Cl and CuL3Cl [where L= Thiourea and its N- and N, N/- mono and di alkyl and phenyl derivatives] have been prepared using Cu(I)CN in the presence of HCl. The complexes have been characterized by thermal, IR and NMR(1H and 13C) spectroscopy. An upfield shift in 13C NMR and downfield shifts in 1H NMR are consistent with the sulfur coordination to Copper(I). The disappearance of a band around 2200 cm⁻¹ in IR and a resonance around 146 ppm in 13C NMR indicates that during the course of reaction the cyanide group of the Copper(I) salt has been replaced by chloride leading to the formation of chlorido complexes.
1798
73455
Optimization of Photocatalytic Degradation of Para-Nitrophenol in Visible Light by Nitrogen and Phosphorus Co-Doped Zinc Oxide Using Factorial Design of Experimental
Abstract:
In this study, Nitrogen and Phosphorous co-doped Zinc Oxide (NPZ) was prepared through a solvent-free reaction. The NPZ was characterized by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy. The photocatalytic activity of the catalyst was investigated by monitoring the degradation of para-nitrophenol (PNP) under visible light irradiation and the process was optimized using factorial design of experiment. The factors investigated were initial concentration of para-nitrophenol, catalyst loading, pH and irradiation time. The characterization results revealed a successful doping of ZnO by nitrogen and phosphorus and an improvement in the surface morphology of the catalyst. The photo-catalyst exhibited improved photocatalytic activity under visible light by 73.8%. The statistical analysis of the optimization result showed that the model terms were significant at 95% confidence level. Interactions plots revealed that irradiation time was the most significant factor affecting the degradation process. The cube plots of the interactions of the variables showed that an optimum degradation efficiency of 66.9% was achieved at 10mg/L initial PNP concentration, 0.5g catalyst loading, pH 7 and 150 minutes irradiation time.
1797
73436
Uranium Adsorption Using a New Composite Material Based on Platelet SBA-15 Supported Tin Salt Tungstomolybdophosphoric Acid
Abstract:
In this work, a new composite adsorbent based on a mesoporous silica SBA-15 with platelet morphology and tin salt of the tungstomolybdophosphoric acid (TWMP) was synthesized and applied for uranium adsorption from aqueous solution. The sample was characterized by X-ray diffraction, Fourier transfer infrared, thermogravimetry and N2 adsorption-desorption analysis and then effect of various parameters such as pH, the concentration of metal ions and contact time on adsorption behavior was examined. The experimental result showed that the adsorption process was explained by the Langmuir isotherm model very well and predominant reaction mechanism is physisorption. Kinetic data of adsorption suggests that the adsorption process can be described by the pseudo-second-order reaction rate model.
1796
73403
Investigation of Ascochyta Blight Resistance in Registered Turkish Chickpea (Cicer arietinum L.) Varieties by using Molecular Techniques
Abstract:
In this study, Ascochyta blight resistance was investigated in 34 registered chickpea varieties, which are widely planting in different regions of Turkey. For this aim, molecular marker techniques, such as STMS, RAPD and ISSR were used. Ta2, Ta146 and Ts54 primers were used for STMS, while UBC733 and UBC681 primers for RAPD, and UBC836 and UBC858 primers for ISSR. Ta2, Ts54 and Ta146 (STMS), and UBC733 (RAPD) primers demonstrated the distinctive feature for Ascochyta blight resistance. Ta2, Ts54 and Ta146 primers yielded the quite effective results in detection of resistant and sensitive varieties. Besides, UBC 733 primer distinguished all kinds of standard did not give any reliable results for other varieties since it demonstrated all as resistant. In addition, monomorphic bands were obtained from UBC681 (RAPD), and UBC836 and UBC858 (ISSR) primers, not demonstrating reliable results in detection of resistance against Ascochyta blight disease. Obtained results informed us about both disease resistance and genetic diversity in registered Turkish chickpea varieties.
1795
73383
In vivo Antimalarial Activity of the Methanol Extract of Myosortis scorpioides Against Plasmodium berghei in Albino Mice
Abstract:
The methanol extract of Myosortis scorpioides L. was screened for the presence of secondary metabolites and was earlier tested for the median lethal dose LD₅₀ using Swiss albino mice to ascertain the in vivo acute toxicity and hence the practically safe dose to be used in a three model antimalarial investigation. The result of the phytochemical screening indicated the presence of alkaloids, terpenes, tannins, flavonoids, saponins and anthraquinones. The extract was found to be very toxic to the mice (LD50 = 2,828.43mg/Kg), which guided our choice for practically safe dose in the three models of the antimalarial evaluations. The result of the suppressive test showed a significant % suppression compared to the control with values of 49.91%, 56.72%, and 65.63% for the doses 100mg/kg, 150mg/kg, and 250mg/kg respectively. The result of the prophylactic (residual malaria infection) tests showed a significant level of inhibition compared to the control (43.22%, 52.45%, 85.70%) for the three doses as above. The curative (established malaria infection) tests also showed a significant level of parasite suppression compared to the control with % suppression of 66.73%, 70.20%, and 73.96% for the doses 100, 150, and 250mg/kg respectively. The result justified the use of Myosortis scorpioides L as a remedy to malaria infection by the traditional medicine practitioners in Adamawa State Nigeria.
1794
73372
Wastes for Cleaning Water: Evaluation of Chicken Feathers for Metal Ions Removal
Abstract:
Poultry industry produces a huge amount of chicken feathers waste worldwide around. Nowadays, high environmental and economic impacts are associated with the handling of this left-over since chicken feathers (CFs) are a truly waste that requires management and treatment (incineration, compost, etc.), causing high costs compared with the near zero value of the feathers. Therefore, during lasts years there has been an interest to valorize CFs to obtain value-added products such as biocomposites, biosorbents, filter media, insulation materials and tissue engineering scaffolds. The main aim of this study was to explore the potential use of CFs waste for removing heavy metals from water, in order to propose more environmental friendly alternative technologies for preventing the pollution of water. For this purpose, preliminary biosorption kinetic tests of Cu2+ ion were carried out and modeled in order to determine the necessary equilibrium time to achieve constant sorption. Likewise, the isotherms of the biosorption were studied and modelled in order to determine the biosorption capacity and its characteristics. Regarding the origin of CFs and their sanitization, they were taken from a slaughterhouse and, successively, stabilized by an oxidative cleaning process using aqueous hydrogen peroxide, dried, and crushed to a maximum size of 1 mm. To perform the kinetic study, 0.4 g of crushed CFs were added to several aliquots of 40mL of a 0.2mM aqueous solutions of Cu2+ with a pH=5-6 adjusted with HCl (0.001M). Solutions were placed on a rotating shaker (ELMI. Intelli-Mixer, RM-2M) at constant agitation (50 rpm), at room temperature (23ºC) and for different periods (ranging from 2 to 1200 minutes). Samples were filtered through glass microfiber filters (pore size 1.2µm), and the concentrations of Cu2+ ion was analyzed by atomic absorption spectrophotometry (GBC 932AA spectrophotometer). Similarly, the biosorption isotherms were carried out adding 0.4 g of crushed CFs to 40mL of several solutions with different concentrations of Cu2+, ranging from 0.2 to 6 mM for 30 minutes. Other operational conditions such as pH, rotation speed and temperature were identical to those of kinetic studies. Data obtained by the kinetic study indicate that the percentage of biosorbed metal ion increases with time contact and rapidly reaches the equilibrium at a time no greater than 15 minutes. Concretely, for the initial concentration 0.2 mM, the percentage of metal ion removal was ca. 94% at 15 minutes of contact. The kinetic experimental data fitted well the well-known pseudo-second order model with a biosortion rate constant of about k2=132.7 (g CFs/mmol Cu2+•min) with a fitting r value 0.999. Besides, the biosorption isotherms of Cu2+ were correlated with common isotherm equations such as Freundlich, Langmuir and Temkin, being the second mathematical model the one that best fits the experimentally obtained data (r=0.988). The maximal biosorption capacity was 0.1 mmol/g CFs. These results proved that the mechanism controlling the biosorption is based on distinct specific sites capable to retain the metal ion. It is reasonable to assume that the existing interaction takes place between the anionic carboxylic groups of the CFs and the metal ion. The authors thank the financial support from project ref.MAT2015-65392-C2-1-R (MINECO/FEDER).
1793
73329
Synthesis, Characterization and Applications of Some Selected Dye-Functionalized P and N-Type Nanoparticles in Dye Sensitized Solar Cells
Abstract:
Inorganic n-type (TiO2, CdO) and p-type (NiO, CuO) metal oxide nanoparticles were synthesized by a facile wet chemical method at room temperature. The morphological, compositional, structural and optical properties were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, FT-IR, XRD analysis, UV/Visible and fluorescence spectroscopy. All semiconducting nanoparticles were photosensitized with Ru (II) based Z907 dye in ethanol solvent by grafting. Grafting of dye on the surface of nanoparticles was confirmed by UV/Visible and FT-IR spectroscopy. The synthesized photo-active nanohybrid was thoroughly blended with P3HT, a solid electrolyte and I-V measurements under solar stimulated radiations 1000 W/m2 (AM 1.5) were recorded. Maximum incident photon to current conversion efficiency (IPCE) of 0.9% was achieved with dye functionalized Z907-TiO2 hybrid, IPCE of 0.72% was achieved with bulk-heterojunction of TiO2-Z907-CuO and IPCE of 0.68% was attained with nanocomposite of TiO2-CdO. TiO2 based Solar cells have maximum Jscvalue i.e.4.63 mA/cm2. Dye-functionalized TiO2-based photovoltaic devices were found more efficient than the reference device but the morphology of the device was a major check in progress.
1792
73326
Extractive Desulfurization of Fuels Using Choline Chloride-Based Deep Eutectic Solvents
Abstract:
Desulfurization process is required by most, if not all refineries, to achieve ultra-low sulfur fuel, that contains less than 10 ppm sulfur. A lot of research works and many effective technologies have been studied to achieve deep desulfurization process in moderate reaction environment, such as adsorption desulfurization (ADS), oxidative desulfurization (ODS), biodesulfurization and extraction desulfurization (EDS). Extraction desulfurization using deep eutectic solvents (DESs) is considered as simple, cheap, highly efficient and environmentally friend process. In this work, four DESs were designed and synthesized. Choline chloride (ChCl) was selected as typical hydrogen bond acceptors (HBA), and ethylene glycol (EG), glycerol (Gl), urea (Ur) and thiourea (Tu) were selected as hydrogen bond donors (HBD), from which a series of deep eutectic solvents were synthesized. The experimental data showed that the synthesized DESs showed desulfurization affinities towards the thiophene species in cyclohexane solvent. Ethylene glycol molecules showed more affinity to create hydrogen bond with thiophene instead of choline chloride. Accordingly, ethylene glycol choline chloride DES has the highest extraction efficiency.