Search results for: relative binding affinity

Authors: Javad Shamsi Soosahab, Reza Ziaie Moayed

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The compressive and tensile bearing capacity of helical piles in sand is investigated by means of numerical modeling. The analyses are carried out using two-dimensional finite-element software, Optum G2. The load–displacement behavior under compression and tension is compared in different relative densities for constant and various elastic modulus. The criterion used to find the ultimate axial load is the load corresponding to 5% of the helical diameter. The results show that relative density of sand plays an essential role in the response of ultimate capacities towards various condition. Increase in elastic modulus with depth is found to play a relatively more significant role to the increase in ultimate compressive load capacities, however tension bearing capacity decreases.

Keywords: helical piles, Optum G2, relative density, constant and various elastic modulus

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Authors: Satoshi Furukawa, Satomu Morita, Lisa Wingenfeld, Katsuji Nishi, Masahito Hitosugi

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We studied the expression of hypoxia-related antigens (e.g., cold-inducible antigens and apoptotic antigens) in the myocardium and the cerebellumthat were obtained from individuals after death by carbon monoxide or hypothermia. The immunohistochemistry results revealed that expression of cold-inducible RNA binding protein (CIRBP) and RNA-binding protein 3 (RBM3) may be associated with hpyothermic and the hypoxic conditions. The expression of CIRBP and RBM3 in the myocardium was different from their expression in the cerebellum, especially in the Purkinje cells. The results indicate that agonal duration influences antigen expression. In the hypothermic condition, the myocardium uses more ATP since the force of the excitation-contraction coupling of the myocardium increases by more than 400% when the experimental temperature is reduced from 35°C to 25°C. The results obtained in this study indicate that physicians should pay attention to the myocardium when cooling the patient’s body to protect the brain.

Keywords: carbon monoxide death, cerebellum, CIRBP, hypothermic death, myocardium, RBM3

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Authors: Mohamed M. Ibrahim, Gaber A. M. Mersal, Salih Al-Juaid, Samir A. El-Shazly

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A series of mixed ligand complexes, viz., [Cu(BPy)(Gly)X]Y {X = Cl (1), Y = 0; X = 0, Y = ClO4- (2); X = H2O, Y = NO3- (3); X = H2O, Y = CH3COO- (4); and [Cu(BPy)(Gly)-(H2O)]2(SO4) (5) have been synthesized. Their structures and properties were characterized by elemental analysis, thermal analaysis, IR, UV–vis, and ESR spectroscopy, as well as electrochemical measurements including cyclic voltammetry, electrical molar conductivity, and magnetic moment measurements. Complexes 1 and 2 formed slightly distorted square-pyramidal coordination geometries of CuN3OCl and CuN3O2, respectively in which the N,O-donor glycine and N,N-donor bipyridyl bind at the basal plane with chloride ion or water as the axial ligand. Complex 3 shows square planar CuN3O coordination geometry, which exhibits chemically significant hydrogen bonding interactions besides showing coordination polymer formation. The superoxide dismutase and catalase-like activities of all complexes were tested and were found to be promising candidates as durable electron-transfer catalyst being close to the efficiency of the mimicking enzymes displaying either catalase or tyrosinase activity to serve for complete reactive oxygen species (ROS) detoxification, both with respect to superoxide radicals and related peroxides. The DNA binding interaction with super coiled pGEM-T plasmid DNA was investigated by using spectral (absorption and emission) titration and electrochemical techniques. The results revealed that DNA intercalate with complexes 1 and 2 through the groove binding mode. The calculated intrinsic binding constant (Kb) of 1 and 2 were 4.71 and 2.429 × 105 M−1, respectively. Gel electrophoresis study reveals the fact that both complexes cleave super coiled pGEM-T plasmid DNA to nicked and linear forms in the absence of any additives. On the other hand, the interaction of both complexes with DNA, the quasi-reversible CuII/CuI redox couple slightly improves its reversibility with considerable decrease in current intensity. All the experimental results indicate that the bipyridyl mixed copper(II) complex (1) intercalate more effectively into the DNA base pairs.

Keywords: enzyme mimics, mixed ligand complexes, X-ray structures, antioxidant, DNA-binding, DNA cleavage

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Authors: Gulmira Kenenbay, Urishbay Chomanov, Aruzhan Shoman, Rabiga Kassimbek

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The main task of the meat-processing industry is the production of meat products as the main source of animal protein, ensuring the vital activity of the human body, in the required volumes, high quality, diverse assortment. Providing the population with high-quality food products what are biologically full, balanced in composition of basic nutrients and enriched by targeted physiologically active components, is one of the highest priority scientific and technical problems to be solved. In this regard, the formulation of a new brine from sprouted wheat for meat delicacies from horse meat, beef and pork has been developed. The new brine contains flavored aromatic ingredients, juice of the germinated wheat and vegetable juice. The viscosity of meat of horse meat, beef and pork were studied during massaging. Thermodynamic indices, water activity and binding energy of horse meat, beef and pork with application of new brine are investigated. A recipe for meat products with vegetable additives has been developed. Organoleptic evaluation of meat products was carried out. Physicochemical parameters of meat products with vegetable additives are carried out. Analysis of the obtained data shows that the values of the index aw (water activity) and the binding energy of moisture in the experimental samples of meat products are higher than in the control samples. It has been established by investigations that with increasing water activity and the binding energy of moisture, the tenderness of ready meat delicacies increases with the use of a new brine.

Keywords: compounding, functional products, delicatessen products, brine, vegetable additives

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Authors: Hasan Basri Jumin

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Application of crude palm oil waste combined to suitable concentration of benzyl-adenine give the significant effect to mean relative growth rate of vegetable plants and the same pattern in net assimilation rate crude palm oil waste has also significantly increased during 28 days old plants. Combination of treatment of suitable concentration of crude palm oil and benzyl adenine increased the growth and production of vegetable plants. The relative growth rate of vegetable plants was rapid 3 weeks after planting and gradually decreased at the end of the harvest time period. Combination of 400 mg.l-1 CPO with 1.0 mgl-1 till 10mgl-1 BA increased the Mean Relative Growth Rate (MRGR), Net assimilation rate (NAR), Leaf area and dry weight of Brassica juncea, Brassica oleraceae and Lactuca sativa.

Keywords: benzyladenine, crude-palm-oil, nutrient, vegetable, waste

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Authors: Yingqian Chen, Sergei Manzhos

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Organic electrodes are a way to achieve high rate (high power) and environment-friendly batteries. We present a computational density functional theory study of Li and Na storage in tetracyanoethylene based molecular and crystalline materials. Up to five Li and Na atoms can be stored on TCNE chemisorbed on doped graphene (corresponding to ~1000 mAh/gTCNE), with binding energies stronger than cohesive energies of the Li and Na metals by 1-2 eV. TCNE has been experimentally shown to form a crystalline material with Li with stoichiometry Li-TCNE. We confirm this computationally and also predict that a similar crystal based of Na-TCNE is also stable. These crystalline materials have well defined channels for facile Li or Na ion insertion and diffusion. Specifically, Li and Na binding energies in Li-TCNE and Na-TCNE crystals are about 1.5 eV and stronger than the cohesive energy of Li and Na, respectively. TCNE immobilized on conducting graphene-based substrates and Li/Na-TCNE crystals could therefore become efficient anode materials for organic Li and Na ion batteries, with which it should also be possible to avoid reduction of common battery electrolytes.

Keywords: organic ion batteries, tetracyanoethylene, cohesive energies, electrolytes

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Authors: Sulaiman Gafar Muhamad

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A rapid spectrophotometric method for the micro-determination of phenylephrine-HCl (PHE) has been developed. The proposed method involves the coupling of phenylephrine-HCl with diazotized 2,4-dinitroaniline in alkaline medium at λmax 455 nm. Under the present optimum condition, Beer’s law was obeyed in the range of 1.0-20 μg/ml of PHE with molar absorptivity of 1.915 ×104 l. mol-1.cm-1, with a relative error of 0.015 and a relative standard deviation of 0.024%. The current method has been applied successfully to estimate phenylephrine-HCl in pharmaceutical preparations (nose drop and syrup).

Keywords: diazo-coupling, 2, 4-dinitroaniline, phenylephrine-HCl, spectrophotometry

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Authors: Emad A. Shalaby

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Cancer is a disease that causes abnormal cell proliferation and invades nearby tissues. Lung cancer is the second most frequent cancer worldwide. Natural anti-cancer drugs have been developed with low side effects and toxicity. Citrus peels and extracts have been demonstrated to have significant pharmacological and physiological effects as a result of the high concentration of phenolic compounds found in citrus fruits, particularly peels. Tangerine peels can serve as an effective source of bioactive substances such as phenolics, flavonoids, and catechins, which have antioxidant, antibacterial, anticancer, and anti-inflammatory properties. Consequently, this work aims to determine the anticancer activity of ethanol extract of Tangerine peels against the A549 cell line and identify the phenolic compound profile (19 compounds) by using HPLC. Anticancer and antioxidant potentials of the extract were evaluated by MTT assay and TLC- TLC-bioautography sprayed with DPPH reagent, respectively. The obtained results revealed that tangerine peel extract showed significant activity against the A549 cell line with IC50 of 97.66 μg/mL. HPLC analysis proved that the highest concentration is naringenin 464.05 mg/g. More studies indicate that naringenin has significant anticancer potential on A549 cancer cells. The results showed that naringenin binds t0 EGFR protein in A549 with high binding affinity and thus may reduce lung cancer cell migration and enhance the apoptosis of cancer cells. From the obtained results it could be concluded that tangerine peel extract is an effective anti-cancer agent that may potentially serve as a natural therapeutic option for lung cancer treatment.

Keywords: tangerine peel, A549 cell line, anticancer, naringenin, HPLC analysis, naringenin, TLC bioautography

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Authors: Hasan Basri Jumin

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Using the slaughterhouse waste combined to suitable dose of nitrogen fertilizer to Apium glaviolen gives the significant effect to mean relative growth rate. The same pattern also showed significantly in net assimilation rate. The net assimilation rate increased significantly during 42 days old plants. Combination of treatment of 100 ml/l animal slaughterhouse waste and 0.1 g/kg nitrogen fertilizer/kg soil increased the vegetative growth of Apium glaviolens. The biomass of plant and mean relative growth rate of Apium glaviolens were rapidly increased in 4 weeks after planting and gradually decreased after 35 days at the harvest time. Combination of 100 ml/l slaughterhouse waste and applied 0.1 g/kg nitrogen fertilizer has increased all parameters. The highest vegetative growth, biomass, mean relative growth rate and net assimilation rate were received from 0.56 mg-l.m-2.days-1.

Keywords: Apium glaviolent, nitrogen, pollutant, slaughterhouse, waste

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Authors: Henok Hailemariam, Frank Wuttke

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Collapsible soils are weak soils that appear to be stable in their natural state, normally dry condition, but rapidly deform under saturation (wetting), thus generating large and unexpected settlements which often yield disastrous consequences for structures unwittingly built on such deposits. In this study, a prediction model for the relative subsidence of stressed collapsible soils based on dielectric permittivity measurement is presented. Unlike most existing methods for soil subsidence prediction, this model does not require moisture content as an input parameter, thus providing the opportunity to obtain accurate estimation of the relative subsidence of collapsible soils using dielectric measurement only. The prediction model is developed based on an existing relative subsidence prediction model (which is dependent on soil moisture condition) and an advanced theoretical frequency and temperature-dependent electromagnetic mixing equation (which effectively removes the moisture content dependence of the original relative subsidence prediction model). For large scale sub-surface soil exploration purposes, the spatial sub-surface soil dielectric data over wide areas and high depths of weak (collapsible) soil deposits can be obtained using non-destructive high frequency electromagnetic (HF-EM) measurement techniques such as ground penetrating radar (GPR). For laboratory or small scale in-situ measurements, techniques such as an open-ended coaxial line with widely applicable time domain reflectometry (TDR) or vector network analysers (VNAs) are usually employed to obtain the soil dielectric data. By using soil dielectric data obtained from small or large scale non-destructive HF-EM investigations, the new model can effectively predict the relative subsidence of weak soils without the need to extract samples for moisture content measurement. Some of the resulting benefits are the preservation of the undisturbed nature of the soil as well as a reduction in the investigation costs and analysis time in the identification of weak (problematic) soils. The accuracy of prediction of the presented model is assessed by conducting relative subsidence tests on a collapsible soil at various initial soil conditions and a good match between the model prediction and experimental results is obtained.

Keywords: collapsible soil, dielectric permittivity, moisture content, relative subsidence

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Authors: Tahir Majeed, Michael Handschuh, René Meier

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Rheumatoid arthritis patients have swelling and pain at the joints of the hand. The regions where the patient feels pain also show increased body temperature. Thermal cameras can be used to detect the rise in temperature of the affected regions. To monitor the disease progression of rheumatoid arthritis patients, they must visit the clinic regularly for scanning and examination. After scanning and evaluation, the dosage of the medicine is regulated accordingly. To monitor the disease progression over time, the correlation between the images between different visits must be established. It has been observed that by using low-cost thermal cameras, the thermal measurements do not remain the same over time, even within a single scanning. In some situations, temperatures can vary as much as 2°C within the same scanning sequence. In this paper, it has been shown that although the absolute temperature varies over time, the relative difference between the different regions remains similar. Results have been computed over four scanning sequences and are presented.

Keywords: relative thermal difference, rheumatoid arthritis, thermal imaging, thermal sensors

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Authors: Sofia G. Meirinho, Luis G. Dias, António M. Peres, Lígia R. Rodrigues

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The emerging development of electrochemical aptasen sors has enabled the easy and fast detection of protein biomarkers in standard and real samples. Biomarkers are produced by body organs or tumours and provide a measure of antigens on cell surfaces. When detected in high amounts in blood, they can be suggestive of tumour activity. These biomarkers are more often used to evaluate treatment effects or to assess the potential for metastatic disease in patients with established disease. Osteopontin (OPN) is a protein found in all body fluids and constitutes a possible biomarker because its overexpression has been related with breast cancer evolution and metastasis. Currently, biomarkers are commonly used for the development of diagnostic methods, allowing the detection of the disease in its initial stages. A previously described RNA aptamer was used in the current work to develop a simple and sensitive electrochemical aptasensor with high affinity for human OPN. The RNA aptamer was biotinylated and immobilized on a gold electrode by avidin-biotin interaction. The electrochemical signal generated from the aptamer–target molecule interaction was monitored electrochemically using cyclic voltammetry in the presence of [Fe (CN) 6]−3/− as a redox probe. The signal observed showed a current decrease due to the binding of OPN. The preliminary results showed that this aptasensor enables the detection of OPN in standard solutions, showing good selectivity towards the target in the presence of others interfering proteins such as bovine OPN and bovine serum albumin. The results gathered in the current work suggest that the proposed electrochemical aptasensor is a simple and sensitive detection tool for human OPN and so, may have future applications in cancer disease monitoring.

Keywords: osteopontin, aptamer, aptasensor, screen-printed electrode, cyclic voltammetry

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Authors: Khwaja Naweed Seddiqi, Zabihullah Mahdi, Shigeo Honma

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Recently increasing oil production from petroleum reservoirs is one of the most important issues in the global energy sector. So, in this paper, the recovery of oil by the waterflooding technique from petroleum reservoir are considered. To investigate the aforementioned phenomena, the relative permeability of two immiscible fluids in sand is measured in the laboratory based on the steady-state method. Two sorts of oils, kerosene and heavy oil, and water are pumped simultaneously into a vertical sand column with different pumping ratio. From the change in fractional discharge measured at the outlet, a method for determining the relative permeability is developed focusing on the displacement mechanism in sand. Then, displacement mechanism of two immiscible fluids in the sand is investigated under the Buckley-Leveret frontal displacement theory and laboratory experiment. Two sorts of experiments, one is the displacement of pore water by oil, the other is the displacement of pore oil by water, are carried out. It is revealed that the relative permeability curves display tolerably different shape owing to the properties of oils, and produce different amount of residual oils and irreducible water saturation.

Keywords: petroleum reservoir engineering, relative permeability, two-phase flow, immiscible displacement in porous media, steady-state method, waterflooding

Procedia PDF Downloads 247

Authors: Thanusha D. Abeywickrama, Inoka C. Perera, Genji Kurisu

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Tuberculosis, considered being as the ninth leading cause of death worldwide, cause from a single infectious agent M. tuberculosis and the drug resistance nature of this bacterium is a continuing threat to the world. Therefore TB preventing treatment is expanding, where this study designed to analyze the regulatory mechanism of GntR transcriptional regulator gene Rv0792c, which lie between several genes codes for some hypothetical proteins, a monooxygenase and an oxidoreductase. The gene encoding Rv0792c was cloned into pET28a and expressed protein was purified to near homogeneity by Nickel affinity chromatography. It was previously reported that the protein binds within the intergenic region (BS region) between Rv0792c gene and monooxygenase (Rv0793). This resulted in binding of three protein molecules with the BS region suggesting tight control of monooxygenase as well as its own gene. Since monooxygenase plays a key role in metabolism, this gene may have a global regulatory role. The natural ligand for this regulator is still under investigation. In relation to the Rv0792 protein structure, a Circular Dichroism (CD) spectrum was carried out to determine its secondary structure elements. Percentage-wise, 17.4% Helix, 21.8% Antiparallel, 5.1% Parallel, 12.3% turn and 43.5% other were revealed from CD spectrum data under room temperature. Differential Scanning Calorimetry (DSC) was conducted to assess the thermal stability of Rv0792, which the melting temperature of protein is 57.2 ± 0.6 °C. The graph of heat capacity (Cp) versus temperature for the best fit was obtained for non-two-state model, which concludes the folding of Rv0792 protein occurs through stable intermediates. Peak area (∆HCal ) and Peak shape (∆HVant ) was calculated from the graph and ∆HCal / ∆HVant was close to 0.5, suggesting dimeric nature of the protein.

Keywords: CD spectrum, DSC analysis, GntR transcriptional regulator, protein structure

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Authors: Priyal Chikhaliwala, Sudeshna Chandra

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Liver cancer is one of the most common malignant tumors with poor prognosis. This is because liver cancer does not exhibit any symptoms in early stage of disease. Increased serum level of AFP is clinically considered as a diagnostic marker for liver malignancy. The present diagnostic modalities include various types of immunoassays, radiological studies, and biopsy. However, these tests undergo slow response times, require significant sample volumes, achieve limited sensitivity and ultimately become expensive and burdensome to patients. Considering all these aspects, electrochemical biosensors based on dendrimer-magnetic nanoparticles (MNPs) was designed. Dendrimers are novel nano-sized, three-dimensional molecules with monodispersed structures. Poly-amidoamine (PAMAM) dendrimers with eight –NH₂ groups using ethylenediamine as a core molecule were synthesized using Michael addition reaction. Dendrimers provide added the advantage of not only stabilizing Fe₃O₄ NPs but also displays capability of performing multiple electron redox events and binding multiple biological ligands to its dendritic end-surface. Fe₃O₄ NPs due to its superparamagnetic behavior can be exploited for magneto-separation process. Fe₃O₄ NPs were stabilized with PAMAM dendrimer by in situ co-precipitation method. The surface coating was examined by FT-IR, XRD, VSM, and TGA analysis. Electrochemical behavior and kinetic studies were evaluated using CV which revealed that the dendrimer-Fe₃O₄ NPs can be looked upon as electrochemically active materials. Electrochemical immunosensor was designed by immobilizing anti-AFP onto dendrimer-MNPs by gluteraldehyde conjugation reaction. The bioconjugates were then incubated with AFP antigen. The immunosensor was characterized electrochemically indicating successful immuno-binding events. The binding events were also further studied using magnetic particle imaging (MPI) which is a novel imaging modality in which Fe₃O₄ NPs are used as tracer molecules with positive contrast. Multicolor MPI was able to clearly localize AFP antigen and antibody and its binding successfully. Results demonstrate immense potential in terms of biosensing and enabling MPI of AFP in clinical diagnosis.

Keywords: alpha-fetoprotein, dendrimers, electrochemical biosensors, magnetic nanoparticles

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Authors: Nigus Maregu Demewoz, Shu-Kai Yeh

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Low-density nanocellular foam is a fascinating new-generation advanced material due to its mechanical strength and thermal insulation properties. In nanocellular foam, reducing the density increases the insulation ability. However, producing a nanocellular foam of densities less than 0.3 with a cell size of less than 100 nm is very challenging. In this study, poly (methyl methacrylate) (PMMA) was blended with Polyether block amide (PEBAX) to study the effects of PEBAX on the nanocellular foam structure of the PMMA matrix. We added 2 wt% of PEBAX in the PMMA matrix, and the PEBAX nanostructured domain size of 45 nm was well dispersed in the PMMA matrix. The foaming result produced a new generation special bouquet-like nanocellular foam of cell size less than 50 nm with a relative density of 0.24. Also, we were able to produce a nanocellular foam of a relative density of about 0.17. In addition to thermal insulation applications, bouquet-like nanocellular foam may be expected for filtration applications.

Keywords: nanocellular foam, low-density, cell size, relative density, PMMA/PEBAX

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Authors: Richard K. Jolley, Jonathan A. Coffman

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Since Enterococci has been implicated in oral disease, we hypothesized the transmission of avian Enterococci to humans via fecal-oral transmission facilitated by adherence to dental plaque. To demonstrate the capability of Enterococci to bind to a dental plaque we filtered avian excreta and incubated the filtrate on a sucrose-induced, Streptococcus mutans biofilm. The biofilm was washed several times with a detergent to remove bacteria binding non-specifically to the biofilm, DNA was isolated from the biofilm, 16S rDNA was amplified, sequenced by Ion Torrent DNA sequencing and analyzed with bioinformatics. Enterococci and other known bacterial pathogens were shown to adhere to the biofilm. Culturing the washed biofilm with Bile Esculin Azide (BEA) agar also confirmed the presence of Enterococci as verified with Sanger sequencing. The results suggest that Enteroccoci in avian excreta has the ability to adhere to human dental plaque and may be a mechanism of entry when humans encounter contaminated aerosols, water or food.

Keywords: Enterococci, avian excreta, dental plaque, NGS

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Authors: Wen-Jay Lee, Kuo-Ning Chiang

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The graphene binding with silicon substrate has apparently Schottky barriers property, which can be used in the application of solar cell and light source. Because graphene has only one atom layer, the atomistic structure of graphene binding with the silicon surface plays an important role to affect the properties of graphene. In this work, temperature effect on the morphology of graphene sheet attached on different crystal planes of silicon substrates are investigated by Molecular dynamics (MD) (LAMMPS, developed by Sandia National Laboratories). The results show that the covered graphene sheet would cause the structural deformation of the surface Si atoms of stubtrate. To achieve a stable state in the binding process, the surface Si atoms would adjust their position and fit the honeycomb structure of graphene after the graphene attaches to the Si surface. The height contour of graphene on different plane of silicon surfaces presents different pattern, leading the local residual stress at the interface. Due to the high density of dangling bond on the Si (111)7x7 surface, the surface of Si(111)7x7 is not matching with the graphene so well in contrast with Si(100)2x1and Si(111)2x1. Si(111)7x7 is found that only partial silicon adatoms are rearranged on surface after the attachment when the temperature is lower than 200K, As the temperature gradually increases, the deformation of surface structure becomes significant, as well as the residue stress. With increasing temperature till the 815K, the graphene sheet begins to destroy and mixes with the silicon atoms. For the Si(100)2x1 and Si(111)2x1, the silicon surface structure keep its structural arrangement with a higher temperature. With increasing temperature, the residual stress gradually decrease till a critical temperatures. When the temperature is higher than the critical temperature, the residual stress gradually increases and the structural deformation is found on the surface of the Si substrates.

Keywords: molecular dynamics, graphene, silicon, Schottky barriers, interface

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Authors: Nigus Maregu Demewoz, Shu-Kai Yeh

Abstract:

Low-density nanocellular foam is a fascinating new-generation advanced material due to its mechanical strength and thermal insulation properties. In nanocellular foam, reducing the density increases the insulation ability. However, producing a nanocellular foam of densities less than 0.3 with a cell size of less than 100 nm is very challenging. In this study, poly (methyl methacrylate) (PMMA) was blended with Polyether block amide (PEBAX) to study the effects of PEBAX on the nanocellular foam structure of the PMMA matrix. We added 2 wt% of PEBAX in the PMMA matrix, and the PEBAX nanostructured domain size of 45 nm was well dispersed in the PMMA matrix. The foaming result produced a new generation special bouquet-like nanocellular foam of cell size less than 50 nm with a relative density of 0.24. Also, we were able to produce a nanocellular foam of a relative density of about 0.17. In addition to thermal insulation applications, bouquet-like nanocellular foam may be expected for filtration applications.

Keywords: nanocellular foam, low-density, cell size, relative density, PMMA/PEBAX blend

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Authors: Maryam Nejat Dehkordi, Per Lincoln, Hassan Momtaz

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Interaction of Schiff base complexes of iron and manganese (iron [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) chloride, [Fe Salen]Cl, manganese [N, N’ Bis (5-(triphenyl phosphonium methyl) salicylidene) -1, 2 ethanediamine) acetate) with DNA were investigated by spectroscopic and isothermal titration calorimetry techniques (ITC). The absorbance spectra of complexes have shown hyper and hypochromism in the presence of DNA that is indication of interaction of complexes with DNA. The linear dichroism (LD) measurements confirmed the bending of DNA in the presence of complexes. Furthermore, isothermal titration calorimetry experiments approved that complexes bound to DNA on the base of both electrostatic and hydrophobic interactions. Furthermore, ITC profile exhibits the existence of two binding phases for the complex. Antibacterial activity of ligand and complexes were tested in vitro to evaluate their activity against the gram positive and negative bacteria.

Keywords: Schiff base complexes, ct-DNA, linear dichroism (LD), isothermal titration calorimetry (ITC), antibacterial activity

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Authors: Shanna Swart, Caryn Fenner, Athanasios Kotsiopoulos, Susan Harrison

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Linear alkanes are produced as by-products from the increasing use of gas-to-liquid fuel technologies for synthetic fuel production and offer great potential for value addition. Their current use as low-value fuels and solvents do not maximize this potential. Therefore, attention has been drawn towards direct activation of these aliphatic alkanes to more useful products such as alcohols, aldehydes, carboxylic acids and derivatives. Cytochrome P450 monooxygenases (P450s) can be used for activation of these aliphatic alkanes using whole-cells or cell-free systems. Some limitations of whole-cell systems include reduced mass transfer, stability and possible side reactions. Since the P450 systems are little studied as cell-free systems, they form the focus of this study. Challenges of a cell-free system include co-factor regeneration, substrate availability and enzyme stability. Enzyme immobilization offers a positive outlook on this dilemma, as it may enhance stability of the enzyme. In the present study, 2 different P450s (CYP153A6 and CYP102A1) as well as the relevant accessory enzymes required for electron transfer (ferredoxin and ferredoxin reductase) and co-factor regeneration (glucose dehydrogenase) have been expressed in E. coli and purified by metal affinity chromatography. Glucose dehydrogenase (GDH), was used as a model enzyme to assess the potential of various enzyme immobilization strategies including; surface attachment on MagReSyn® microspheres with various functionalities and on electrospun nanofibers, using self-assembly based methods forming Cross Linked Enzymes (CLE), Cross Linked Enzyme Aggregates (CLEAs) and spherezymes as well as in a sol gel. The nanofibers were synthesized by electrospinning, which required the building of an electrospinning machine. The nanofiber morphology has been analyzed by SEM and binding will be further verified by FT-IR. Covalent attachment based methods showed limitations where only ferredoxin reductase and GDH retained activity after immobilization which were largely attributed to insufficient electron transfer and inactivation caused by the crosslinkers (60% and 90% relative activity loss for the free enzyme when using 0.5% glutaraldehyde and glutaraldehyde/ethylenediamine (1:1 v/v), respectively). So far, initial experiments with GDH have shown the most potential when immobilized via their His-tag onto the surface of MagReSyn® microspheres functionalized with Ni-NTA. It was found that Crude GDH could be simultaneously purified and immobilized with sufficient activity retention. Immobilized pure and crude GDH could be recycled 9 and 10 times, respectively, with approximately 10% activity remaining. The immobilized GDH was also more stable than the free enzyme after storage for 14 days at 4˚C. This immobilization strategy will also be applied to the P450s and optimized with regards to enzyme loading and immobilization time, as well as characterized and compared with the free enzymes. It is anticipated that the proposed immobilization set-up will offer enhanced enzyme stability (as well as reusability and easy recovery), minimal mass transfer limitation, with continuous co-factor regeneration and minimal enzyme leaching. All of which provide a positive outlook on this robust multi-enzyme system for efficient activation of linear alkanes as well as the potential for immobilization of various multiple enzymes, including multimeric enzymes for different bio-catalytic applications beyond alkane activation.

Keywords: alkane activation, cytochrome P450 monooxygenase, enzyme catalysis, enzyme immobilization

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Authors: Naveeda Akhtar Qureshi, Wajiha

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Coccidiosis is a protozoan parasitic disease of genus Eimeria. It is an avian infection causing a great economic loss of 3 billion USD per year globally. A number of anticoccidial drugs are in use however many of them have side effects and cost effective. With increase in poultry demand throughout the world there is a need of more drugs and vaccines against coccidiosis. The present study is based upon the use of F. racemosa a medicinal plant to be a potential source of anticoccidial agents. The methanolic leaves extract was fractionated by column and thin layer chromatography and got nineteen fractions. Each fraction different concentrations was evaluated for its anticoccidial properties in an invitro experiment against E. tenella, E. necatrix and E. mitis. The anticoccidial active fractions were further characterized by spectroscopy (UV-Vis, FTIR) and GC-MS analysis. The in silico molecular docking of active fractions identified compounds were carried out. Among all fractions significantly maximum sporulation inhibition efficacy was shown by F-19 (67.11±2.18) followed by F-15 (65.21±1.34) at concentration of 30mg/ml against E. tenella. The significantly highest sporozoites viability inhibition was shown by F-19 (69.23±2.11) followed by F-15 (67.14±1.52) against E. necatrix at concentration 30mg/ml. Anticoccidial active fractions 15 and 19 showed peak spectrum at 207 and 202nm respectively by UV analysis. Their FTIR analysis confirmed the presence of carboxylic acid, amines, phenols, etc. Anticoccidial active compounds like Cyclododecane methanol, oleic acid, Octadecanoic acid, etc were identified by GC-MS analysis. Identified compounds in silico molecular docking study showed that cyclododecane methanol of F-19 and oleic acid of F-15 showed highest binding affinity with target S-Adenosylmethionine synthase. Hence for further authentication in vivo anticoccidial studies are recommended.

Keywords: ficus racemosa, cluster fig, column chromatography, anticoccidial fractions, GC-MS, molecular docking., s-adenosylmethionine synthase

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Authors: O. Moussous, T. Medjadj

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The suitability of a Fricke dosimeter for the measurement of a relative depth dose profile and the peak scatter factors was studied. The measurements were carried out in the secondary standard dosimetry laboratory at CRNA Algiers using a collimated 60Co gamma source teletherapy machine. The measurements were performed for different field sizes at the phantom front face, at a fixed source-to-phantom distance of 80 cm. The dose measurements were performed by first placing the dosimeters free-in-air at the distance-source-detector (DSD) of 80.5 cm from the source. Additional measurements were made with the phantom in place. The water phantom type Med-Tec 40x40x40 cm for vertical beam was used in this work as scattering martial. The phantom was placed on the irradiation bench of the cobalt unit at the SSD of 80 cm from the beam focus and the centre of the field coincided with the geometric centre of the dosimeters placed at the depth in water of 5 mm Relative depth dose profile and Peak scatter factors measurements were carried out using our Fricke system. This was intercompared with similar measurements by ionization chamber under identical conditions. There is a good agreement between the relative percentage depth–dose profiles and the PSF values measured by both systems using a water phantom.

Keywords: Fricke dosimeter, depth–dose profiles, peak scatter factors, DSD

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Authors: Yasuyuki Takahashi, Genta Hoshi, Kyoko Saito

Abstract:

Objectives: The objective of this study was to evaluate the reproducibility of I-123-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4- iodophenyl) nortropane (I-123 FP-CIT) SPECT by using specific binding ratio (SBR) in phantom studies and Parkinson’s Disease (PD) patients. Methods: We made striatum phantom originally and confirmed reproducibility. The phantom studies changed head position and accumulation of FP-CIT, each. And image processing confirms influence on SBR by 30 cases. 30 PD received a SPECT for 3 hours post injection of I-123 FP-CIT 167MBq. Results: SBR decreased in rotatory direction by the patient position by the phantom studies. And, SBR improved the influence after the attenuation and the scatter correction in the cases (y=0.99x+0.57 r2=0.83). However, Stage II recognized dispersion in SBR by low accumulation. Conclusion: Than the phantom studies that assumed the normal cases, the SPECT image after the attenuation and scatter correction had better reproducibility.

Keywords: 123I-FP-CIT, specific binding ratio, Parkinson’s disease

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Authors: Hussein M. Maghrabie, M. Attalla, Hany. A. Mohamed, M. Salem, E. Specht

Abstract:

An experimental investigation is carried out on counter-flow Ranque–Hilsch vortex tube (RHVT). The present work is carried out to study the effect of nozzle aspect ratio, tube length and the inlet pressure (P_i) on the coefficient of performance and energy separation of a RHVT. Further, the effect of moist air with different relative humidity (RH) 40, 60, 80 % is also achieved. The air relative humidity is adjusted using air humidification/dehumidification unit. The experimental study accomplished for number of nozzle N=6, with inner diameter D=7.5 mm., and length of the vortex tube (L) 75, 97.5, and 112.5 mm. The results show that the relative humidity has a significant effect on coefficient of performance and energy separation of a RHVT.

Keywords: COP, counter-flow Ranque–Hilsch vortex tube, energy separation, humid air

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Authors: N. Demertzis, J. L. Bowen

Abstract:

Sepsis is a complex and rapidly evolving condition, resulting from uncontrolled prolonged activation of host immune system due to pathogenic insult. The aim of this study is the development of a multiplex electrochemical sensing platform, capable of detecting both pathogen associated and host immune markers to enable the rapid and definitive diagnosis of sepsis. A combination of aptamers and molecular imprinting approaches have been employed to generate sensing systems for lipopolysaccharide (LPS), c-reactive protein (CRP) and procalcitonin (PCT). Gold working electrodes were mechanically polished and electrochemically cleaned with 0.1 M sulphuric acid using cyclic voltammetry (CV). Following activation, a self-assembled monolayer (SAM) was generated, by incubating the electrodes with a thiolated anti-LPS aptamer / dithiodibutiric acid (DTBA) mixture (1:20). 3-aminophenylboronic acid (3-APBA) in combination with the anti-LPS aptamer was used for the development of the hybrid molecularly imprinted sensor (apta-MIP). Aptasensors, targeting PCT and CRP were also fabricated, following the same approach as in the case of LPS, with mercaptohexanol (MCH) replacing DTBA. In the case of the CRP aptasensor, the SAM was formed following incubation of a 1:1 aptamer: MCH mixture. However, in the case of PCT, the SAM was formed with the aptamer itself, with subsequent backfilling with 1 μM MCH. The binding performance of all systems has been evaluated using electrochemical impedance spectroscopy. The apta-MIP’s polymer thickness is controlled by varying the number of electropolymerisation cycles. In the ideal number of polymerisation cycles, the polymer must cover the electrode surface and create a binding pocket around LPS and its aptamer binding site. Less polymerisation cycles will create a hybrid system which resembles an aptasensor, while more cycles will be able to cover the complex and demonstrate a bulk polymer-like behaviour. Both aptasensor and apta-MIP were challenged with LPS and compared to conventional imprinted (absence of aptamer from the binding site, polymer formed in presence of LPS) and non-imprinted polymers (NIPS, absence of LPS whilst hybrid polymer is formed). A stable LPS aptasensor, capable of detecting down to 5 pg/ml of LPS was generated. The apparent Kd of the system was estimated at 17 pM, with a Bmax of approximately 50 pM. The aptasensor demonstrated high specificity to LPS. The apta-MIP demonstrated superior recognition properties with a limit of detection of 1 fg/ml and a Bmax of 100 pg/ml. The CRP and PCT aptasensors were both able to detect down to 5 pg/ml. Whilst full binding performance is currently being evaluated, there is none of the sensors demonstrate cross-reactivity towards LPS, CRP or PCT. In conclusion, stable aptasensors capable of detecting LPS, PCT and CRP at low concentrations have been generated. The realisation of a multiplex panel such as described herein, will effectively contribute to the rapid, personalised diagnosis of sepsis.

Keywords: aptamer, electrochemical impedance spectroscopy, molecularly imprinted polymers, sepsis

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Authors: Alexey V. Klyuev, Arkady V. Yakimov, Mikhail I. Ryzhkin, Andrey V. Klyuev

Abstract:

Fluctuations of Schottky diode parameters in a structure of the mixer are investigated. These fluctuations are manifested in two ways. At the first, they lead to fluctuations in the transfer factor that is lead to the amplitude fluctuations in the signal of intermediate frequency. On the basis of the measurement data of 1/f noise of the diode at forward current, the estimation of a spectrum of relative fluctuations in transfer factor of the mixer is executed. Current dependence of the spectrum of relative fluctuations in transfer factor of the mixer and dependence of the spectrum of relative fluctuations in transfer factor of the mixer on the amplitude of the heterodyne signal are investigated. At the second, fluctuations in parameters of the diode lead to the occurrence of 1/f noise in the output signal of the mixer. This noise limits the sensitivity of the mixer to the value of received signal.

Keywords: current-voltage characteristic, fluctuations, mixer, Schottky diode, 1/f noise

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Authors: Mthokozisi Simelane

Abstract:

Background: Malaria remains a life-threatening disease in tropical regions despite the advances in the treatment of this disease, it still remains a significant burden as some parasites have become resistant to the currently available drugs. This has created a necessity for the development of alternative, more efficient antimalarial drugs. Warburgia salutaris is a traditional medicinal plant used in malaria treatment by Zulu traditional healers. Materials and methods: The W. salutaris stem-bark was extracted with dichloromethane and the compound was isolated through column chromatography. The compound was identified and characterized by spectroscopic analysis (1H NMR, 13C NMR, IR and MS) and the structure was also confirmed by x-ray crystallography. The anti-plasmodial activity (in vitro) was studied on NF54 Plasmodium falciparum strain (CQS). Cytotoxicity was measured using the MTT assay on HEK239 and HEPG2 cell lines. Docking of Mukaadial acetate was conducted in AutoDock Vina. Structural modifications were conducted in UCSF Chimera and molecular interactions examined in LigPlot. Results: The compound, Mukaadial Acetate showed appreciable inhibition (IC50 0.44±0.10 µg/ml) of the parasite growth and cytotoxicity activity of 0.124±0.109 and 0.199±0.083 (µg/ml) on HEK293 and HEPG2 cells respectively. Molecular docking revealed that Mukaadial Acetate binds to the purine, pyrophosphate and ribose binding sites of the PfHGXPRT with an optimum binding conformation and forms hydrogen bond, steric and hydrophobic interactions with the residues inhabiting the respective binding sites. Conclusion: It is apparent that W. salutaris contains components (including Mukaadial Acetate) that exhibit antimalarial activity. This study scientifically validates the use of this plant in folk medicine.

Keywords: plasmodium falciparum, molecular docking, antimalarial activity, PfHGXPRT, Warburgia salutaris, mukaadial acetate

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Authors: Jae Bok Heo, Yun Mi Lee, Hee Rang Yun

Abstract:

Several GTPases are required for ribosome biogenesis and assembly. We recently characterized rice (Oryza sativa) nuclear/nucleolar GTPase 2 (OsNug2), belonging to the YlqF/YawG family of GTPases, as playing a role in pre-60S ribosomal subunit maturation. To investigate the potential factors involved in regulating the function of OsNug2, yeast two-hybrid screens were carried out using OsNug2 as bait. Rice serine/threonine kinase 1 (OsSTK1) was identified as a potential interacting protein candidate. In vitro pull down and bimolecular fluorescence complementation assays confirmed the interaction between OsNug2 and OsSTK1, and like green fluorescent protein-tagged OsNug2, green fluorescent protein-tagged OsSTK1 was targeted to the nucleus of Arabidopsis protoplasts. OsSTK1 was not found to affect the GTP-binding activity of OsNug2; however, when recombinant OsSTK1 was included in OsNug2 assay reaction mixtures, OsSTK1 increased the GTPase activity of OsNug2. To test whether OsSTK1 phosphorylates OsNug2 in vitro, a kinase assay was performed. OsSTK1 was found to have weak autophosphorylation activity and strongly phosphorylated serine 209 of OsNug2. Yeast complementation testing resulted in a GAL::OsNug2(S209N) mutant-harboring yeast strain exhibiting a growth-defective phenotype on galactose medium at 39°C, divergent from that of a yeast strain harboring GAL::OsNug2. The intrinsic GTPase activity of mutant OsNug2(S209N) was found to be similar to that of OsNug2, was not fully enhanced upon weak binding of OsSTK1. Our findings reported here indicate that OsSTK1 functions as a positive regulator protein of OsNug2 by enhancing the GTPase activity of OsNug2, and that the phosphorylation of serine 209 of OsNug2 is essential for the complete function of OsNug2 in ribosome biogenesis.

Keywords: OsSTK1, OsNug2, GTPase activity, GTP binding activity, phosphorylation

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Authors: Krishnakant Bhole, Neerakallu D. Shivakumar, Shakti Singh Chauhan, Sanketh Tonannavar, Rajath S

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Synthesis of natural-based composite materials is state of the art. This work discusses the preparation and characterization of cellulose nanofibers (CNF) extracted from the bamboo pulp using TEMPO-oxidization and high-pressure homogenization methods. Bio-composites are prepared using synthesized CNF and bamboo particles. Nanocellulose prepared is characterized using SEM and XRD for morphological and crystallinity analysis, and the formation of fibers at the nano level is ensured. Composite specimens are fabricated using these natural sources and subjected to tensile and flexural tests to characterize the mechanical properties such as modulus of elasticity (MOE), modulus of rupture (MOR), and interfacial strength. Further, synthesized nanocellulose is used as a binding agent to prepare particleboards using various natural sources like bamboo, areca nut, and banana in the form of fibers. From the results, it can be inferred that nanocellulose prepared from bamboo pulp acts as a binding agent for making bio-composites. Hence, the concept of using matrix and reinforcement derived from natural sources can be used to prepare green composites that are highly degradable.

Keywords: nanocellulose, biocomposite, CNF, bamboo

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