Search results for: metal compounds

Authors: Sunil Kumar

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For many years, small organic molecules derived naturally from microbes and plants have delivered a number of expedient therapeutic drug agents. The search for naturally occurring lead compounds has continued in recent years as well, with the constituents of marine flora and fauna along with those of telluric microorganisms and plants being investigated for their anti-bacterial and anti-cancer activities. It has been observed that such promising lead molecules incline to promptly generate substantial attention among scientists like synthetic organic chemists and biologists. Subsequently, the availability of a given precious natural product sample may be enriched, and it may be possible to determine a preliminary idea of structure-activity relationships to develop synthetic analogues. For instance, anti-tumor drug topotecan is a synthetic chemical compound similar in chemical structure to camptothecin which is found in extracts of Camptotheca acuminate. Similarly, researchers at AstraZeneca discovered anti-biotic pyrrolamide through a fragment-based lead generation approach from kibdelomycin, which is isolated from Staphylococcus aureuss.

Keywords: anticancer, antibiotic, lead molecule, natural product, synthetic analogues

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Authors: Strahinja Kovačević, Jelena Vladić, Senka Vidović, Zoran Zeković, Lidija Jevrić, Sanja Podunavac Kuzmanović

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Supercritical extracts of highly valuated medicinal plant Satureja montana were prepared by application of supercritical carbon dioxide extraction in the carbon dioxide pressure range from 125 to 350 bar and temperature range from 40 to 60°C. Using GC/MS method of analysis chemical profiles (aromatic constituents) of S. montana extracts were obtained. Self-training artificial neural networks were applied to predict the retention time of the analyzed terpenes in GC/MS system. The best ANN model obtained was multilayer perceptron (MLP 11-11-1). Hidden activation was tanh and output activation was identity with Broyden–Fletcher–Goldfarb–Shanno training algorithm. Correlation measures of the obtained network were the following: R(training) = 0.9975, R(test) = 0.9971 and R(validation) = 0.9999. The comparison of the experimental and predicted retention times of the analyzed compounds showed very high correlation (R = 0.9913) and significant predictive power of the established neural network.

Keywords: ANN regression, GC/MS, Satureja montana, terpenes

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Authors: Meiyan Xing, Cenran Li, Liang Xiang

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Impacts of excess sludge vermicompost on the germination and early growth of plant were tested. The better effect of cow dung vermicompost (CV) on seed germination and seedling growth proved that cow dung was indeed the preferred additive in sludge vermicomposting as reported by plentiful researchers worldwide. The effects and the best amount of application of CV were further discussed. Results demonstrated that seed germination and seedling growth (seedlings number, plant height, stem diameter) were the best and heavy metal (Zn, Pb, Cr and As) contents of plant were the lowest when soil amended with CV by 15%. Additionally, CV fostered higher contents of chlorophyll a and chlorophyll b compared to the control when concentration ranged from 5 to 15%, thereafter a slight increase in chlorophyll content was observed form 15% to 25%. Thus, CV at the optimum proportion of 15% could serve as a feasible and satisfactory way of sludge agricultural utilization of sewage sludge. In summary, sewage sludge can be gainfully utilized in producing organic fertilizer via vermicomposting, thereby not only providing a means of sewage sludge treatment and disposal, but also stimulating the growth of plant and the ability to resist disease.

Keywords: cow dung vermicompost, seed germination, seedling growth, sludge utilization

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Authors: Adil Elrayah, Jie Weng, Esra Suliman

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The mineral in human bone is not pure stoichiometric calcium phosphate (Ca/P) as it is partially substituted by in organic elements. In this study, the copper ions (Cu²⁺) substituted hydroxyapatite (CuHA) powder has been synthesized by the co-precipitation method. The CuHA powder has been used to fabricate CuHA fiber scaffolds by sol-gel process and the following sinter process. The resulted CuHA fibers have slightly different microstructure (i.e. porosity) compared to HA fiber scaffold, which is denser. The mechanical properties test was used to evaluate CuHA, and the results showed decreases in both compression strength and hardness tests. Moreover, the in vitro used endothelial cells to evaluate the angiogenesis of CuHA. The result illustrated that the viability of endothelial cell on CuHA fiber scaffold surfaces tends to antigenic behavior. The results obtained with CuHA scaffold give this material benefit in biological applications such as antimicrobial, antitumor, antigens, compacts, filling cavities of the tooth and for the deposition of metal implants anti-tumor, anti-cancer, bone filler, and scaffold.

Keywords: fiber scaffold, copper ions, hydroxyapatite, in vitro, mechanical property

Procedia PDF Downloads 139

Authors: M. Yildirim, A. S. Kipcak, F. T. Senberber, M. O. Asensio, E. M. Derun, S. Piskin

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Potassium borates, which are widely used in welding and metal refining industry, as a lubricating oil additive, cement additive, fiberglass additive and insulation compound, are one of the important groups of borate minerals. In this study the production of a potassium borate mineral via hydrothermal method is aimed. The potassium source of potassium nitrate (KNO3) was used along with a sodium source of sodium hydroxide (NaOH) and boron source of boric acid (H3BO3). The constant parameters of reaction temperature and reaction time were determined as 80°C and 1 h, respectively. The molar ratios of 1:1:3 (as KNO3:NaOH:H3BO3), 1:1:4, 1:1:5, 1:1:6 and 1:1:7 were used. Following the synthesis the identifications of the produced products were conducted by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR). The results of the experiments and analysis showed in the ratio of 1:1:6, the Santite mineral with powder diffraction file number (pdf no.) of 01-072-1688, which is known as potassium pentaborate (KB5O8•4H2O) was synthesized as best.

Keywords: hydrothermal synthesis, potassium borate, potassium nitrate, santite

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Authors: H. Krarcha

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The structural, elastic, vibrational and thermal properties of AHfO3 compounds with the cubic perovskites structure have been investigated, by employing a first principles method, using the plane wave pseudo potential calculations (PP-PW), based on the density functional theory (DFT), within the local density approximation (LDA). The optimized lattice parameters, independent elastic constants (C11, C12 and C44), bulk modulus (B), compressibility (b), shear modulus (G), Young’s modulus (Y ), Poisson’s ratio (n), Lame´’s coefficients (m, l), as well as band structure, density of states and electron density distributions are obtained and analyzed in comparison with the available theoretical and experimental data. For the first time the numerical estimates of elastic parameters of the polycrystalline AHfO3 ceramics (in framework of the VoigteReusseHill approximation) are performed. The quasi-harmonic Debye model, by means of total energy versus volume calculations obtained with the FP-LAPW method, is applied to study the thermal and vibrational effects. Predicted temperature and pressure effects on the structural parameters, thermal expansions, heat capacities, and Debye temperatures are determined from the non-equilibrium Gibbs functions.

Keywords: Hafnium, elastic propreties, first principles calculation, perovskite

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Authors: Srinivasarao Kondaparla, Utsab Debnath, Awakash Soni, Vasantha Rao Dola, Manish Sinha, Kumkum Kumkum Srivastava, Sunil K. Puri, Seturam B. Katti

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In a focused exploration, we have designed synthesized and biologically evaluated chiral conjugated new chloroquine (CQ) analogs with substituted piperazines as antimalarial agents. In vitro as well as in vivo studies revealed that compound 7c showed potent activity [for in vitro IC₅₀= 56.98nM (3D7), 97.76nM (K1); for in vivo (up to at the dose of 12.5 mg/kg); SI = 3510] as a new lead of antimalarial agent. Other compounds 6b, 6d, 7d, 7h, 8c, 8d, 9a, and 9c are also showing moderate activity against CQ-sensitive (3D7) strain and superior activity against resistant (K1) strain of P. falciparum. Furthermore, we have carried out docking and 3D-QSAR studies of all in-house data sets (168 molecules) of chiral CQ analogs to explain the structure activity relationships (SAR). Our new findings specified the significance of H-bond interaction with the side chain of heme for biological activity. In addition, the 3D-QSAR study against 3D7 strain indicated the favorable and unfavorable sites of CQ analogs for incorporating steric, hydrophobic and electropositive groups to improve the antimalarial activity.

Keywords: piperazines, CQ-sensitive strain-3D7, in-vitro and in-vivo assay, docking, 3D-QSAR

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Authors: D. Baranova, E. Neborak

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Polyphenols, particularly flavonoids like quercetin, fisetin, and kaempferol, have gained significant attention in nutrition due to their antioxidant, senolytic, and anti-inflammatory properties. These compounds are commonly found in various plant-based foods and are represented by diverse subclasses, each with unique health benefits. Understanding their absorption, metabolism, and bioactivity within the human body is crucial for unlocking their full potential. Quercetin, for instance, exists in multiple forms, impacting its solubility and absorption in the intestine. Its intake, often derived from sources like apples, is affected by cooking methods, with medium heat retaining its potency. Fisetin, also present in fruits and vegetables, demonstrates neuroprotective qualities and stability under varied conditions compared to quercetin. Similarly, kaempferol, found in fruits and vegetables, displays antioxidative effects but is influenced by cooking techniques, with specific methods preserving its polyphenolic content better. Overall, these polyphenols offer promising health benefits, yet their optimal dosage and specific dietary recommendations warrant further research to harness their full nutritional potential.

Keywords: polyphenols, flavonoids, absorption, quercetin, kaempferol, fisetin, senolytics, absorption, cooking method

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Authors: Ayu S. Muhamad, Michael Gleeson

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Immunomodulators are substances that alter immune system via dynamic regulation of messenger molecules. It can be divided into immunostimulant and immunosuppressant. It can help to increase immunity of people with a low immune system, and also can help to normalize an overactive immune system. Aim of this study is to investigate the effects of in vitro exposure to low and high doses of several immunomodulators which include caffeine, kaloba and quercetin on antigen-stimulated whole blood culture cytokine production. Whole blood samples were taken from 5 healthy males (age: 32 ± 12 years; weight: 75.7 ± 6.1 kg; BMI: 24.3 ± 1.5 kg/m2) following an overnight fast with no vigorous activity during the preceding 24 h. The whole blood was then stimulated with 50 µl of 100 x diluted Pediacel vaccine and low or high dose of immunomodulators in the culture plate. After 20 h incubation (5% CO2, 37°C), it was analysed using the Evidence Investigator to determine the production of cytokines including IL-2, IL-4, IL-10, IFN-γ, and IL-1α. Caffeine and quercetin showed a tendency towards decrease cytokine production as the doses were increased. On the other hand, an upward trend was evident with kaloba, where a high dose of kaloba seemed to increase the cytokine production. In conclusion, we found that caffeine and quercetin have potential as immunosuppressant and kaloba as immunostimulant.

Keywords: caffeine, cytokine, immunomodulators, kaloba, quercetin

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Authors: Franky Michael Hamonangan Siagian, Affan Maulana, Himawan Tri Bayu Murti Petrus, Panut Mulyono, Widi Astuti

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In this study, the feasibility of the direct electrowinning method was used to produce zero-valent iron from red mud. The bauxite residue sample came from the Tayan mine, Indonesia, which contains high hematite (Fe₂O₃). Before electrolysis, the samples were characterized by various analytical techniques (ICP-AES, SEM, XRD) to determine their chemical composition and mineralogy. The direct electrowinning method of red mud suspended in NaOH was introduced at low temperatures ranging from 30 - 110 °C. Variations of current density, red mud: NaOH ratio and temperature were carried out to determine the optimum operation of the direct electrowinning process. Cathode deposits and residues in electrochemical cells were analyzed using XRD, XRF, and SEM to determine the chemical composition and current recovery. The low-temperature electrolysis current efficiency on Redmud can reach 20% recovery at a current density of 920,945 A/m². The moderate performance of the process was investigated with red mud, which was attributed to the troublesome adsorption of red mud particles on the cathode, making the reduction far less efficient than that with hematite.

Keywords: alumina, red mud, electrochemical reduction, iron production

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Authors: Shahnaz Mansouri, David Martin, Xiao Dong Chen, Meng Wai Woo

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Ultrafine hydrophobic and non-water-soluble drugs can increase the percentage of absorbed compared to their initial dosage. This paper provides a scalable new method of making ultrafine particles of substantially insoluble water compounds specifically, submicron particles of ethanol soluble and water insoluble pharmaceutical materials by steaming an ethanol droplet to prepare a suspension and then followed by immediate drying. This suspension is formed by adding evaporated water molecules as an anti-solvent to the solute of the samples and in early stage of precipitation continued to dry by evaporating both solvent and anti-solvent. This fine particle formation has produced fast dispersion powder in water. The new method is an extension of the antisolvent vapour precipitation technique which exposes a droplet to an antisolvent vapour with reference to the dissolved materials within the droplet. Ultrafine vitamin D3 and ibuprofen particles in the submicron ranges were produced. This work will form the basis for using spray dryers as high-throughput scalable micro-precipitators.

Keywords: single droplet drying, nano size particles, non-water-soluble drugs, precipitators

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Authors: Daniel Y. Abebe, Jaehyouk Choi

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There are several types of metal-based devices conceived as dampers for the seismic energy absorber whereby damages to the major structural components could be minimized for both new and existing structures. This paper aimed to develop and evaluate structural performance of slit circular shear panel damper for passive seismic energy protection by inelastic deformation. Structural evaluation was done using commercially available nonlinear FE simulation program. The main parameters considered are: diameter-to-thickness (D/t) ratio and slit length-to-width ratio (l/w). Depending on these parameters three different buckling modes and hysteretic behaviors were found: yielding prior to buckling without strength degradation, yielding prior to buckling with strength degradation, and yielding with buckling and strength degradation which forms pinching at initial displacement. The susceptible location at which the possible crack is initiated is also identified for selected specimens using rupture index.

Keywords: slit circular shear panel damper, hysteresis characteristics, slip length-to-width ratio, D/t ratio, FE analysis

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Authors: Reginald Umunakwe, Obinna Chibuzor Okoye, Uzoma Samuel Nwigwe, Damilare John Olaleye, Akinlabi Oyetunji

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The potential for the development of PPS-AlMMCs as light weight material for industrial applications was investigated. Periwinkle shells were milled and the density of the particles determined. Particulate periwinkle shell of particle size 75µm was used to reinforce aluminium 6063 alloy at 10wt% filler loading using two-step stir casting technique. The composite materials were stirred for five minutes in a semi-solid state and the stirring time varied as 3, 6 and 9 minutes at above the liquidus temperature. A specimen was also produced with pre-heated filler. The effect of variation in stirring time and reinforcement pre-heating on the porosity of the composite materials was investigated. The results of the analysis show that a composition of reinforcement pre-heating and stirring for 3 minutes produced a composite material with the lowest porosity of 1.05%.

Keywords: composites, periwinkle shell, two-step casting, porosity

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Authors: Mehran Fadaeinasab, Hamed Karimian, Najihah Mohd Hashim, Hapipah Mohd Ali

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In this study, three indole alkaloids namely; rauvolfine B, macusine B, and isoreserpiline have been isolated from the dichloromethane crude extract of Rauvolfia reflexa bark (Apocynaceae). The structural elucidation of the isolated compounds has been performed using spectral methods such as UV, IR, MS, 1D, and 2D NMR. Rauvolfine B showed anti proliferation activity on HCT-116 cancer cell line, its cytotoxicity induction was observed using MTT assay in eight different cell lines. Annexin-V is serving as a marker for apoptotic cells and the Annexin-V-FITC assay was carried out to observe the detection of cell-surface Phosphatidylserine (PS). Apoptosis was confirmed by using caspase-8 and -9 assays. Cell cycle arrest was also investigated using flowcytometric analysis. rauvolfine B had exhibited significantly higher cytotoxicity against HCT-116 cell line. The treatment significantly arrested HCT-116 cells in the S phase. Together, the results presented in this study demonstrated that rauvolfine B inhibited the proliferation of HCT-116 cells and programmed cell death followed by cell cycle arrest.

Keywords: apocynacea, indole alkaloid, apoptosis, cell cycle arrest

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Authors: C. Mekala, Indumathi M. Nambi

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Nitrogen pollution in groundwater arising from wastewater and fertilizer application through vadose zone is a major problem and it causes a prime risk to groundwater based drinking water supplies. Nitrogenous compounds namely ammonium, nitrate and nitrite fate and transport in soil subsurface were studied experimentally. The major process like sorption, leaching, biotransformation involving microbial growth kinetics, and biological clogging due to biomass growth were assessed and modeled with advection-dispersion reaction equations for ammonium, nitrate and acetate in a saturated, heterogeneous soil medium. The transport process was coupled with freundlich sorption and monod inhibition kinetics for immobile bacteria and permeability reduction due to biomass growth will be verified and validated with the numerical model. This proposed mathematical model will be very helpful in the development of a management model for a sustainable and safe wastewater reuse strategies such as irrigation and groundwater recharge.

Keywords: nitrogen species transport, transformation, biological clogging, biokinetic parameters, contaminant transport model, saturated soil

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Authors: N. Yaiphaba, Elizabeth C. H.

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YPO₄ nanoparticles codoped with Eu³⁺(5 at.%) and Bi³⁺(0, 1, 3, 5, 7, 10, 12, 15, 20 at.%) have been prepared in poly acrylic acid (PAA)-H₂O medium by hydrothermal synthesis by maintaining a temperature of 180oC. The crystalline structure of as-prepared and 500oC annealed samples transforms from tetragonal (JCPDS-11-0254) to hexagonal phase (JCPDS-42-0082) with increasing concentration of Bi³⁺ ions. However, 900oC annealed samples exhibit tetragonal structure. The crystallite size of the particles varies from 19-50 nm. The luminescence intensity increases at lower concentration of Bi³⁺ ions and then decreases with increasing Bi3+ ion concentrations. The luminescence intensity further increases on annealing at 500oC and 900oC. Further, 900oC annealed samples show sharp increase in luminescence intensity. Moreover, the samples follow bi-exponential decay indicating energy transfer from donor to the activator or non-uniform distribution of ions in the samples. The samples on excitation at 318 nm exhibit near white emission while at 394 nm excitation show emission in the red region. The as-prepared samples are redispersible and have potential applications in display devices, metal ion sensing, biological labelling, etc.

Keywords: charge transfer, sensitizer, activator, annealing

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Authors: Ogbonnaya Nwokoro, Florence O. Anya

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Nutritional factors relating to the production of linamarase from Lactobacillus delbrueckii NRRL B–763 were investigated. The microorganism was cultivated in a medium containing 1% linamarin. Enzyme was produced using a variety of carbon substrates but the highest enzyme activity was detected in the presence of salicin (522 U/ml) after 48 h while the lowest yield was observed with CM cellulose (38 U/ml) after 72 h. Enzyme was not produced in the presence of cellobiose. Among a variety of nitrogen substrates tested, peptone supported maximum enzyme production (412 U/ml) after 48 h. Lowest enzyme production was observed with urea (40 U/ml). Organic nitrogen substrates generally supported higher enzyme productivity than inorganic nitrogen substrates. Enzyme activity was observed in the presence of Mn2+ (% relative activity = 216) while Hg2+ was inhibitory (% relative activity = 28). Locally-formulated media were comparable to MRS broth in supporting linamarase production by the bacterium. Higher enzyme activity was produced in media with surfactant than in media without surfactant. The enzyme may be useful in enhanced degradation of cassava cyanide.

Keywords: linamarase, locally formulated media, carbon substrates, nitrogen substrates, metal ions

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Authors: M. Moayeri, A. Kaflou

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Decreasing the size of heat exchangers in industries is favorable due to a reduction in the initial costs and maintenance. This can be achieved generally by increasing the heat transfer coefficient, which can be done by increasing tube surface by passive methods named “porous coat”. Since these coatings are often in contact with the fluid, mechanical strength of coatings should be considered as main concept beside permeability and porosity in design, especially in high velocity services. Powder shape affected mechanical property more than other factors. So in this study, the Copper powder with three different shapes (spherical, dendritic and irregular) was coated on Cu-Ni base metal with thickness of ~300µm in a reduction atmosphere (5% H2-N2) and programmable furnace. The morphology and physical properties of coatings, such as porosity, permeability and mechanical strength were investigated. Results show although irregular particle have maximum porosity and permeability but strength level close to spherical powder, in addition, mentioned particle has low production cost, so for creating porous coats in high velocity services these powder recommended.

Keywords: porous coat, permeability, mechanical strength, porosity

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Authors: Sundaram Arulmozhiraja, Kanade Shimizu, Yuta Yamamoto, Satoshi Ichikawa, Maenaka Katsumi, Hiroaki Tokiwa

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Drug discovery is shifting from small molecule based drugs targeting local active site to middle molecules (MM) targeting large, flat, and groove-shaped binding sites, for example, protein-protein interface because at least half of all targets assumed to be involved in human disease have been classified as “difficult to drug” with traditional small molecules. Hence, MMs such as peptides, natural products, glycans, nucleic acids with various high potent bioactivities become important targets for drug discovery programs in the recent years as they could be used for ‘undruggable” intracellular targets. Cell membrane permeability is one of the key properties of pharmacodynamically active MM drug compounds and so evaluating this property for the potential MMs is crucial. Computational prediction for cell membrane permeability of molecules is very challenging; however, recent advancement in the molecular dynamics simulations help to solve this issue partially. It is expected that MMs with high membrane permeability will enable drug discovery research to expand its borders towards intracellular targets. Further to understand the chemistry behind the permeability of MMs, it is necessary to investigate their conformational changes during the permeation through membrane and for that their interactions with the membrane field should be studied reliably because these interactions involve various non-bonding interactions such as hydrogen bonding, -stacking, charge-transfer, polarization dispersion, and non-classical weak hydrogen bonding. Therefore, parameters-based classical mechanics calculations are hardly sufficient to investigate these interactions rather, quantum mechanical (QM) calculations are essential. Fragment molecular orbital (FMO) method could be used for such purpose as it performs ab initio QM calculations by dividing the system into fragments. The present work is aimed to study the cell permeability of middle molecules using molecular dynamics simulations and FMO-QM calculations. For this purpose, a natural compound syringolin and its analogues were considered in this study. Molecular simulations were performed using NAMD and Gromacs programs with CHARMM force field. FMO calculations were performed using the PAICS program at the correlated Resolution-of-Identity second-order Moller Plesset (RI-MP2) level with the cc-pVDZ basis set. The simulations clearly show that while syringolin could not permeate the membrane, its selected analogues go through the medium in nano second scale. These correlates well with the existing experimental evidences that these syringolin analogues are membrane-permeable compounds. Further analyses indicate that intramolecular -stacking interactions in the syringolin analogues influenced their permeability positively. These intramolecular interactions reduce the polarity of these analogues so that they could permeate the lipophilic cell membrane. Conclusively, the cell membrane permeability of various middle molecules with potent bioactivities is efficiently studied using molecular dynamics simulations. Insight of this behavior is thoroughly investigated using FMO-QM calculations. Results obtained in the present study indicate that non-bonding intramolecular interactions such as hydrogen-bonding and -stacking along with the conformational flexibility of MMs are essential for amicable membrane permeation. These results are interesting and are nice example for this theoretical calculation approach that could be used to study the permeability of other middle molecules. This work was supported by Japan Agency for Medical Research and Development (AMED) under Grant Number 18ae0101047.

Keywords: fragment molecular orbital theory, membrane permeability, middle molecules, molecular dynamics simulation

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Authors: M. Abd elfattah, M. Ossman, Nahla A. Taha

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The present work explored the use of Egyptian rice straw, an agricultural waste that leads to global warming problem through brown cloud, as a potential feedstock for the preparation of activated carbon by physical and chemical activation. The results of this study showed that it is feasible to prepare activated carbons with relatively high surface areas and pore volumes from the Egyptian rice straw by direct chemical and physical activation. The produced activated carbon from the two methods (AC1 and AC2) could be used as potential adsorbent for the removal of Fe(III) from aqueous solution contains heavy metals and polluted water. The adsorption of Fe(III) was depended on the pH of the solution. The optimal Fe(III) removal efficiency occurs at pH 5. Based on the results, the optimum contact time is 60 minutes and adsorbent dosage is 3 g/L. The adsorption breakthrough curves obtained at different bed depths indicated increase of breakthrough time with increase in bed depths. A rise in inlet Fe(III) concentration reduces the throughput volume before the packed bed gets saturated. AC1 showed higher affinity for Fe(III) as compared to Raw rice husk.

Keywords: rice straw, activated carbon, Fe(III), fixed bed column, pyrolysis

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Authors: Dmitry Yu. Korulkin, Raissa A. Muzychkina

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Bioactive substances of plant origin can be one of the advanced means of solution to the issue of combined therapy to inflammation. The main advantages of medical plants are softness and width of their therapeutic effect on an organism, the absence of side effects and complications even if the used continuously, high tolerability by patients. Moreover, medial plants are often the only and (or) cost-effective sources of natural biologically active substances and medicines. Along with other biologically active groups of chemical compounds, essential oils with wide range of pharmacological effects became very ingrained in medical practice. Essential oil was obtained by the method hydrodistillation air-dry aerial part of Polygonum L. plants using Clevenger apparatus. Qualitative composition of essential oils was analyzed by chromatography-mass-spectrometry method using Agilent 6890N apparatus. The qualitative analysis is based on the comparison of retention time and full mass-spectra with respective data on components of reference oils and pure compounds, if there were any, and with the data of libraries of mass-spectra Wiley 7th edition and NIST 02. The main components of essential oil are for: Polygonum amphibium L. - γ-terpinene, borneol, piperitol, 1,8-cyneole, α-pinene, linalool, terpinolene and sabinene; Polygonum minus Huds. Fl. Angl. – linalool, terpinolene, camphene, borneol, 1,8-cyneole, α-pinene, 4-terpineol and 1-octen-3-ol; Polygonum alpinum All. – camphene, sabinene, 1-octen-3-ol, 4-carene, p- and o-cymol, γ-terpinene, borneol, -terpineol; Polygonum persicaria L. - α-pinene, sabinene, -terpinene, 4-carene, 1,8-cyneole, borneol, 4-terpineol. Antibacterial activity was researched relating to strains of gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, Streptococcus agalacticae, relating to gram-negative strain Escherichia coli and to yeast fungus Сandida albicans using agar diffusion method. The medicines of comparison were gentamicin for bacteria and nystatin for yeast fungus Сandida albicans. It has been shown that Polygonum L. essential oils has moderate antibacterial effect to gram-positive microorganisms and weak antifungal activity to Candida albicans yeast fungus. At the second stage of our researches wound healing properties of ointment form of 3% essential oil was researched on the model of flat dermal wounds. To assess the influence of essential oil on healing processes the model of flat dermal wound. The speed of wound healing on rats of different groups was judged based on assessment the area of a wound from time to time. During research of wound healing properties disturbance of integral in neither group: general condition and behavior of animals, food intake, and excretion. Wound healing action of 3% ointment on base of Polygonum L. essential oil and polyethyleneglycol is comparable with the action of reference substances. As more favorable healing dynamics was observed in the experimental group than in control group, the tested ointment can be deemed more promising for further detailed study as wound healing means.

Keywords: antibacterial, antifungal, bioactive substances, essential oils, isolation, Polygonum L.

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Authors: Nada Bezić, Valerija Dunkić, Antonija Markovina, Mirko Rušćić

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Valeriana is a genus of the well-known medicinal plant of Valerianacea family and growing wild in the sub-Mediterranean area. This abstract reports the types and distribution of trichomes and phyto-active composition of the essential oil of the Valeriana tuberosa from mountain Kozjak, near Split, Croatia. Two types of glandular trichomes: peltate (one basal epidermal cell, one short stalk cell and a small head) and capitate trichomes (one basal epidermal cell, one elongated stalk cell) were observed on leaf, using light microscopy. We analyzed the composition of the essential oil of stems and leaves of V. tuberosa species. Water distilled essential oils from aerial parts of investigation plant have been analysed by GC and GC/MS using VF-5ms capillary column. The total yield of oil was 0.2%, based on dry weight of samples. Forty compounds representing 94.1% of the total oil of V. tuberosa. This essential oil was characterized by a high concentration of isovaleric acid (17.2%), geranyl isovalerate (12.2%) and caryophyllene oxide (7.7%). The present study gives additional knowledge about micromorphological traits and secondary metabolites contents on the genus Valeriana.

Keywords: essential oil, isovaleric acid, Valeriana tuberosa, Croatia

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Authors: Abu Harera Nadeem, Kingsley Donkor

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Tea is a popular beverage due to its flavour, aroma and antioxidant properties—with the most consumed varieties being green and black tea. Antioxidants in tea can lower the risk of Alzheimer’s and heart disease and obesity. However, these teas contain heavy metals such as Hg, Cd, or Pb, which can cause autoimmune diseases like Graves disease. In this study, 11 heavy metals in various commercial green, black, and oolong tea samples were determined using inductively coupled plasma-mass spectrometry (ICP-MS). Two methods of sample preparation were compared for accuracy and precision, which were microwave-assisted digestion and ultrasonic-assisted extraction. The developed method was further validated by detection limit, precision, and accuracy. Results showed that the proposed method was highly sensitive with detection limits within parts-per-billion levels. Reasonable method accuracy was obtained by spiked experiments. The findings of this study can be used to delve into the link between tea consumption and disease and to provide information for future studies on metal determination in tea.

Keywords: ICP-MS, green tea, black tea, microwave-assisted acid digestion, ultrasound-assisted extraction

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Authors: Thi Huong Vu, Haelee Fenton, Thi Huong Tra Nguyen, Gary Dykes

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In the present study, a submerged fermentation of carob kibble with Saccharomyces cerevisiae (S. cerevisiae) was performed. The total phenolic content and antioxidant activity in fermented carob kibble were determined by Folin–Ciocalteu method and scavenging capacity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS). The study showed that S. cerevisiae improved total phenolic content by 45 % and 50 % in acetone and water extracts respectively. Similarly, the antioxidant capacity of water extracts increased by 25 % and 41%, while acetone extracts indicated by 70% and 80% in DPPH and ABTS respectively. It is also found that initial pH 7.0 was more effective in improvement of total phenolic content and antioxidant activity. The efficiency of treatment was recorded at 15 h. This report suggested that submerged fermentation with S. cerevisiae is a potential and cost effective manner to further increase bioactive compounds in carob kibble, which are in use for food, cosmetic and pharmaceutical industries.

Keywords: antioxidant activity, carob kibble, saccharomyces cerevisiae, submerged fermentation, total phenolics

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Authors: S. Mahdavi, S.R. Allahkaram

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Electrodeposition is a simple and economic technique for precision coating of different shaped substrates with pure metal, alloy or composite films. Dc electrodeposition was used to produce Cr, Co-Cr and Co-Cr/TiO2 nano-composite coatings from Cr(III) based electrolytes onto 316L SS substrates. The effects of TiO2 nano-particles concentration on co-deposition of these particles along with Cr content and microhardness of the coatings were investigated. Morphology of the Cr, Co-Cr and Co-Cr/TiO2 coatings besides their tribological behavior were studied. The results showed that increment of TiO2 nano-particles concentration from 0 to 30 g L-1 in the bath increased their co-deposition and Cr content of the coatings from 0 to 3.5 wt.% and from 23.7 to 31.2 wt.%, respectively. Microhardness of Cr coating was about 920 Hv which was higher than Co-Cr and even Co-Cr/TiO2 films. Microhardness of Co-Cr and Co-Cr/TiO2 coatings were improved by increasing their Cr and TiO2 content. All the coatings had nodular morphology and contained microcracks. Nodules sizes and the number of microcracks in the alloy and composite coatings were lower than the Cr film. Wear results revealed that the Co-Cr/TiO2 coating had the lowest wear loss between all the samples, while the Cr film had the worst wear resistance.

Keywords: Co-Cr alloy, electrodeposition, nano-composite, tribological behavior, trivalent chromium

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Authors: Hassan Zare, Mohammad Jahedi, Mohammad Reza Toroghinejad, Mahmoud Meratian, Marko Knezevic

Abstract:

In this study, the carbon nanotube (CNT) reinforced Al matrix nanocomposites were fabricated by ECAP. Equal Channel Angular Pressing (ECAP) process is one of the most important methods for powder densification due to the presence of shear strain. This method samples with variety passes (one, two, four and eight passes) in C route were prepared at room temperature. A few study about metal matrix nanocomposite reinforced carbon nanotube done, the reaction intersection of interface and carbon nanotube cause to reduce the efficiency of nanocomposite. In this paper, we checked mechanical and physical properties of aluminum-CNT composite that manufactured by ECAP when the composite is deformed. The non-agglomerated CNTs were distributed homogeneously with 2% consolidation in the Aluminum matrix. The ECAP process was performed on the both monolithic and composite with distributed CNT samples for 8 passes.

Keywords: powder metallurgy, ball mill attrition, ultrasonic, consolidation

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Authors: Ashish Kumar Singh, Preeti Tiwari, Shubham Srivastava, Rajiv Prakash, Herman Terryn, Gopal Ji

Abstract:

Corrosion inhibition potential of azo dyes namely Allura red (AR), Sunset Yellow (SY) and Amaranth (AN) have been investigated in 0.5 M H2SO4 solutions by electrochemical impedance spectroscopy (EIS), Tafel polarization curves, linear polarization curves, open circuit potential (ocp) curves, UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques. Amaranth dye is found to provide highest corrosion inhibition (90 %) against mild steel corrosion in sulfuric acid solutions among all the tested dyes; while SY and AR dye shows 80% and 78% corrosion inhibition efficiency respectively. The electrochemical measurements and surface morphology analysis reveal that molecular adsorption of dyes at metal acid interface is accountable for inhibition of mild steel corrosion in H2SO4 solutions. The adsorption behavior of dyes has been investigated by various isotherms models, which verifies that it is in accordance with Langmuir isotherm.

Keywords: mild steel, Azo dye, EIS, Langmuir isotherm

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Authors: Safa Boudhaouia, Mohamed Amen Gahbiche, Eliane Giraud, Wacef Ben Salem, Philippe Dal Santo

Abstract:

Multi-point forming (MPF) and asymmetric incremental forming (ISF) are two flexible processes for sheet metal manufacturing. To take advantages of these two techniques, a hybrid process has been developed: The Multipoint Incremental Forming (MPIF). This process accumulates at once the advantages of each of these last mentioned forming techniques, which makes it a very interesting and particularly an efficient process for single, small, and medium series production. In this paper, an experimental and a numerical investigation of this technique are presented. To highlight the flexibility of this process and its capacity to manufacture standard and complex shapes, several pieces were produced by using MPIF. The forming experiments are performed on a 3-axis CNC machine. Moreover, a numerical model of the MPIF process has been implemented in ABAQUS and the analysis showed a good agreement with experimental results in terms of deformed shape. Furthermore, the use of an elastomeric interpolator allows avoiding classical local defaults like dimples, which are generally caused by the asymmetric contact and also improves the distribution of residual strain. Future works will apply this approach to other alloys used in aeronautic or automotive applications.

Keywords: incremental forming, numerical simulation, MPIF, multipoint forming

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Authors: Blessing A. Aderibigbe

Abstract:

Combination therapy is a treatment approach that is used to prevent the emergence of drug resistance. This approach is used for the treatment of many chronic and infectious diseases. Potentiating agents are currently explored in combination therapy, resulting in excellent therapeutic outcomes. Breast cancer and malaria are two chronic conditions responsible globally for high death rates. In this research, a class of polymer-drug conjugates containing potentiating agents with either antimalarial or anticancer drugs were prepared by Michael Addition Polymerization reaction and ring-opening polymerization reaction. Conjugation of potentiating agents with bioactive compounds into the polymers resulted in conjugates with good water solubility, highly selective and non-toxic. In vitro cytotoxicity and in vitro antiplasmodial evaluation on the conjugates revealed that the conjugates were more effective when compared to the free drugs. The drug release studies further showed that the release profile of the drugs from the conjugates was sustained. The findings revealed the potential of polymer-drug conjugates to overcome drug toxicity and drug resistance, which is common with the currently used antimalarial and anticancer drugs.

Keywords: anticancer, antimalarials, combination therapy, polymer-drug conjugates

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Authors: Manel Boulakoud, Abdelkader Chouaih, Fodil Hamzaoui

Abstract:

In the present work we are interested in the determination of the Molecular electrostatic potential (MEP) in Z-3N(2-Ethoxyphenyl), 2-N’(2-Ethoxyphenyl) imino thiazolidin-4-one molecule by ab initio and Density Functional Theory (DFT) in the ground state. The MEP is related to the electronic density and is a very useful descriptor in understanding sites for electrophilic attack and nucleophilic reactions as well as hydrogen bonding interactions. First, geometry optimization was carried out using Hartree–Fock (HF) and DFT methods with 6-311G(d,p) basis set. In order to get more information on the molecule, its stability has been analyzed by natural bond orbital (NBO) analysis. Mulliken population analyses have been calculated. Finally, the molecular electrostatic potential (MEP) and HOMO-LUMO energy levels have been performed. The calculated HOMO and LUMO energies show also the charge transfer within the molecule. The energy gap obtained is about 4 eV which explain the stability of the studied compound. The obtained molecular electrostatic potential from the two methods confirms the nature of the electron charge transfer at the molecular shell and locate the electropositive part and the electronegative part in molecular scale of the title compound.

Keywords: DFT, ab initio, HOMO-LUMO, organic compounds

Procedia PDF Downloads 519