Search results for: compounds identification

Authors: Juliana A. B. Silva, Caio H. T. L. Albuquerque, Leonardo L. dos Santos, Cristiane K. Oliveira, Ivani Malvestiti, Fernando Hallwass, Ricardo L. Longo

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Complexes with lanthanide ions have been extensively studied due to their applications as luminescent, magnetic and catalytic materials as molecular or extended crystals, thin films, glasses, polymeric matrices, ionic liquids, and in solution. NMR chemical shift data in solution have been reported and suggest fluxional structures in a wide range of coordination compounds with rare earth ions. However, the fluxional mechanisms for these compounds are still not established. This structural fluxionality may affect the photophysical, catalytic and magnetic properties in solution. Thus, understanding the structural interconversion mechanisms may aid the design of coordination compounds with, for instance, improved (electro)luminescence, catalytic and magnetic behaviors. The [Eu(btfa)₃bipy] complex, where btfa= 4,4,4-trifluoro-1-phenyl-1,3-butanedionate and bipy= 2,2’-bipiridyl, has a well-defined X-ray crystallographic structure and preliminary 1H NMR data suggested a structural fluxionality. Thus, we have investigated a series of coordination compounds with lanthanide ions [Ln(btfa)₃L], where Ln = La, Eu, Gd or Yb and L= bipy or phen (phen=1,10-phenanthroline) using a combined theoretical-experimental approach. These complexes were synthesized and fully characterized, and detailed NMR measurements were obtained. They were also studied by quantum chemical computational methods (DFT-PBE0). The aim was to determine the relevant factors in the structure of these compounds that favor or not the fluxional behavior. Measurements of the 1H NMR signals at variable temperature in CD₂Cl₂ of the [Eu(btfa)₃L] complexes suggest that these compounds have a fluxional structure, because the crystal structure has non-equivalent btfa ligands that should lead to non-equivalent hydrogen atoms and thus to more signals in the NMR spectra than those obtained at room temperature, where all hydrogen atoms of the btfa ligands are equivalent, and phen ligand has an effective vertical symmetry plane. For the [Eu(btfa)₃bipy] complex, the broadening of the signals at –70°C provides a lower bound for the coalescence temperature, which indicates the energy barriers involved in the structural interconversion mechanisms are quite small. These barriers and, consequently, the coalescence temperature are dependent upon the radii of the lanthanide ion as well as to their paramagnetic effects. The PBE0 calculated structures are in very good agreement with the crystallographic data and, for the [Eu(btfa)₃bipy] complex, this method provided several distinct structures with almost the same energy. However, the energy barrier for structural interconversion via dissociative pathways were found to be quite high and could not explain the experimental observations. Whereas the pseudo-rotation pathways, involving the btfa and bipy ligands, have very small activation barriers, in excellent agreement with the NMR data. The results also showed an increase in the activation barrier along the lanthanide series due to the decrease of the ionic radii and consequent increase of the steric effects. TD-DFT calculations showed a dependence of the ligand donor state energy with different structures of the complex [Eu(btfa)₃phen], which can affect the energy transfer rates and the luminescence. The energy required to promote the structural fluxionality may also enhance the luminescence quenching in solution. These results can aid in the design of more luminescent compounds and more efficient devices.

Keywords: computational chemistry, lanthanide-based compounds, NMR, structural fluxionality

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Authors: Mastaneh Safarnejad Shad, Wim Dehaen, Steven De Jonghe

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Since CXCR4 is the main coreceptor of HIV-1 and plays an important role in human immunodeficiency virus (HIV) entry, numerous efforts were directed towards the discovery of new classes of small molecules that act as CXCR4 antagonists. In addition, CXCR4 antagonists are potentially useful in the treatment of several other disorders, such as cancer cell metastasis, leukemia cell proliferation, rheumatoid arthritis, and pulmonary fibrosis. Since AMD3100 (plerixafor) is the only CXCR4 antagonist which obtained approval by the Food and Drug Administration (FDA), we were motivated to investigate a new category of molecules as CXCR4 antagonists. Most of the scaffolds which have been studied so far as CXCR4 antagonists are based on the tetrahydroquinoline (THQ) moiety in which AMD11070 (mavorixafor), GSK-812394, and TIQ15 displayed the most potent CXCR4 antagonism. Due to the high potency of these scaffolds, two different series of compounds were prepared in this work. In the first set, the THQ moiety is coupled to an amine chain and various isoquinoline derivatives (prepared by an in-house developed triazolization strategy), of which the upper part of molecules is identical to AMD11070 and TIQ15. In the second category of compounds, the THQ moiety was simplified by the synthesis of a substituted pyridine moiety. In order to investigate if CXCR4 antagonism requires the presence of an isoquinoline moiety, the corresponding pyridine analogues were also prepared. In both series of compounds, potent CXCR4 antagonism was noticed.

Keywords: CXCR4 coreceptor, CXCR4 antagonists, HIV inhibitor, tetrahydroquinoline

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Authors: Cibele F. Oliveira, Debora P. Jaeschke, Rodrigo R. Laurino, Amanda R. Andrade, Ligia D. F. Marczak

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Raspberry is well-known as a good source of phenolic compounds, mainly anthocyanin. Some studies pointed out the importance of these bioactive compounds consumption, which is related to the decrease of the risk of cancer and cardiovascular diseases. The most consumed raspberry products are juices, yogurts, ice creams and jellies and, to ensure the safety of these products, raspberry is commonly pasteurized, for enzyme and microorganisms inactivation. Despite being efficient, the pasteurization process can lead to degradation reactions of the bioactive compounds, decreasing the products healthy benefits. Therefore, the aim of the present work was to evaluate moderate electric field (MEF) and ultrasound (US) technologies application on the pasteurization process of raspberry juice and compare the results with conventional pasteurization process. For this, phenolic compounds, anthocyanin content and physical-chemical parameters (pH, color changes, titratable acidity) of the juice were evaluated before and after the treatments. Moreover, microbiological analyses of aerobic mesophiles microorganisms, molds and yeast were performed in the samples before and after the treatments, to verify the potential of these technologies to inactivate microorganisms. All the pasteurization processes were performed in triplicate for 10 min, using a cylindrical Pyrex® vessel with a water jacket. The conventional pasteurization was performed at 90 °C using a hot water bath connected to the extraction cell. The US assisted pasteurization was performed using 423 and 508 W cm-2 (75 and 90 % of ultrasound intensity). It is important to mention that during US application the temperature was kept below 35 °C; for this, the water jacket of the extraction cell was connected to a water bath with cold water. MEF assisted pasteurization experiments were performed similarly to US experiments, using 25 and 50 V. Control experiments were performed at the maximum temperature of US and MEF experiments (35 °C) to evaluate only the effect of the aforementioned technologies on the pasteurization. The results showed that phenolic compounds concentration in the juice was not affected by US and MEF application. However, it was observed that the US assisted pasteurization, performed at the highest intensity, decreased anthocyanin content in 33 % (compared to in natura juice). This result was possibly due to the cavitation phenomena, which can lead to free radicals formation and accumulation on the medium; these radicals can react with anthocyanin decreasing the content of these antioxidant compounds in the juice. Physical-chemical parameters did not present statistical differences for samples before and after the treatments. Microbiological analyses results showed that all the pasteurization treatments decreased the microorganism content in two logarithmic cycles. However, as values were lower than 1000 CFU mL-1 it was not possible to verify the efficacy of each treatment. Thus, MEF and US were considered as potential alternative technologies for pasteurization process, once in the right conditions the application of the technologies decreased microorganism content in the juice and did not affected phenolic and anthocyanin content, as well as physical-chemical parameters. However, more studies are needed regarding the influence of MEF and US processes on microorganisms’ inactivation.

Keywords: MEF, microorganism inactivation, anthocyanin, phenolic compounds

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Authors: Jelena Vulić, Jasna Čanadanović-Brunet, Gordana Ćetković, Sonja Djilas, Vesna Tumbas Šaponjac

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Caneberries (raspberries and blackberries) are among the most popular berries in the world, which are consumed as fresh and processed to juice, jams, confitures and other products or as ingredients for different foods. These fruits are known as a rich source of phenolic compounds such as phenolic acids and anthocyanins. Antioxidant activity (AA) of caneberry juices was improved by addition of phenolic compounds which were extracted from two raspberry cultivars (Rubus idaeus, cv. 'Willamette' (RW) and 'Meeker' (RM)) and two blackberry cultivars (Rubus fruticosus, cv. 'Čačanka' (BC) and 'Thornfree' (BT)) pomace, a by-product in juice processing. The total phenolic contents in raspberry and blackberry pomace extracts were determined spectrophotometrically using the Folin-Ciocalteu reagens. The phenolic concentrations in caneberries (RW, RM, BC and BT) pomace extracts were 43.67 ± 2.13 mg GAE/g, 26.25 ± 1.18 mg GAE/g, 46.01 ± 3.26 mg GAE/g and 61.59 ± 1.14 mg GAE/g, respectively. In order to obtain enriched juices, phenolic compounds were applied at concentration of 0.05 mg GAE/ 100 ml. Antioxidant activities of caneberry juices and caneberry enriched juices were measured using stable 1.1-diphenyl-2-picrylhydrazyl (DPPH) radicals. AADPPH of RW, RM, BC and BT juices and enriched juices with addition of 0.01 µg GAE/ml, changed from 37.12% to 93.01%, 23.26% to 91.57%, 53.61% to 95.65% and 52.06% to 93.13%, respectively, while IC50 values of RW, RM, BC and BT juices and enriched juices were diminished 6.33, 19.00, 6.33 and 4.75 times, respectively. Based on the obtained results it can be concluded that phenolic enriched juices were significantly more effective on DPPH radicals. Caneberry juices enriched with waste material are a good source of natural pigments and antioxidants and could be used as functional foods.

Keywords: caneberry, enriched juice, phenolic antioxidant, DPPH radical

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Authors: Tran Hung Tra, Hao Dinh Duong, Masakazu Okazaki

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Copper 1100 and aluminum 1050 plates with a thickness of 5.0 mm are butt-joint using friction stir welding. The tool offset is linearly varied along the welding path. Two welding regimes, using the same linear tool offset but in opposite directions, are applied for fabricating two Cu/Al plates. The material flow is dominated by both tool offset and offset history. The intermetallic compounds layer and interface morphology in each welded plate are formed in a different manner. As a result, the bonding strength and fracture behavior between two welded plates are significantly distinct. The role of interface morphology on fracture behavior is analyzed by the finite element method.

Keywords: Cu/Al dissimilar welding, offset history, interface morphology, intermetallic compounds, strength and fracture

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Authors: Sonja Djilas, Aleksandra Velićanski, Dragoljub Cvetković, Siniša Markov, Eva Lončar, Vesna Tumbas Šaponjac, Milica Vinčić

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Due to high content of bioactive compounds, sour cherry possesses antioxidant and antimicrobial activity. Additionally, waste material from industrial processing of sour cherry is also a good source of bioactive compounds. The aim of this study was to screen the antimicrobial activity and determine the minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) of sour cherry pomace extract. Tested strains were Gram-negative bacteria (Escherichia coli ATCC 25922, Salmonella typhimurium ATCC 14028 and wild isolates Escherichia coli and Salmonella sp.), Gram-positive bacteria (Staphylococcus aureus ATCC 11632, Bacillus cereus ATCC 10876 and wild isolates Staphylococcus saprophyticus and Bacillus sp.) and yeasts (Saccharomyces cerevisiae 112, Hefebank Weihenstephan and Candida albicans ATCC 10231). Antimicrobial activity was tested by disc-diffusion method and agar-well diffusion method. MIC and MBC were determined by microdilution method. Screening tests showed that Gram-negative bacteria were resistant to tested extract, with exception of Salmonella typhimurium and Salmonella sp. for which only zones of reduced growth appeared. However, Gram-positive bacteria were more sensitive where the highest clear zones appeared with 100 µl of extract applied. There was no activity against tested yeasts. MIC and MBC values were in the range 3.125-37.5 mg/ml and 6.25-100 mg/ml, respectively. The most susceptible strain was Staphylococcus aureus while the most resistant was Bacillus sp. where MBC was not found in tested concentration range. Sour cherry pomace possesses high antibacterial potential, which indicates that this waste material is a promising source of bioactive compounds and could be used as a functional food ingredient.

Keywords: antimicrobial activity, sour cherry, pomace, bioactive compounds

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Authors: Essebti Dhahri

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We present a new refrigerant La₀.₇Ca₀.₁₅Sr₀.₁₅Mn₁₋ₓGaₓO₃ (x = 0.0-0.1) manganites. These compounds were prepared by the sol-gel method. The refinement of the X-ray diffraction reveals that all samples crystallize in a rhombohedral structure (space group R3 ̅c). Detailed measurements of the magnetization as a function of temperature and magnetic applied field M (µ₀H, T) were carried out. From the M(µ₀H, T) curves, we have calculated the magnetic entropy change (ΔSM) according to the Maxwell relation. The temperature dependence of the magnetization M(T) reveals a decrease of M when increasing the x content. The magnetic entropy change (ΔSM) reaches a maximum value near room temperature. It was also found that this compound exhibits a large magnetocaloric effect MCE which increases when decreasing Ga concentration. So, the studied compounds could be considered potential materials for magnetic refrigeration application.

Keywords: magnetic measurements, Rietveld refinement, magnetic refrigeration, magnetocaloric effect

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Authors: A. Szabó Nagy, J. Szabó, Zs. Csanádi, J. Erdős

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In Hungary, the measurement of ambient PM10-bound polycyclic aromatic hydrocarbon (PAH) concentrations is great importance for a number of reasons related to human health, the environment and compliance with European Union legislation. However, the monitoring of PAHs associated with PM2.5 aerosol fraction is still incomplete. Therefore, the main aim of this study was to investigate the concentration levels of PAHs in PM2.5 urban aerosol fraction. PM2.5 and associated PAHs were monitored in November 2014 in an urban site of Győr (Northwest Hungary). The aerosol samples were collected every day for 24-hours over two weeks with a high volume air sampler provided with a PM2.5 cut-off inlet. The levels of 19 PAH compounds associated with PM2.5 aerosol fraction were quantified by a gas chromatographic method. Polluted air quality for PM2.5 (>25 g/m3) was indicated in 50% of the collected samples. The total PAHs concentrations ranged from 2.1 to 37.3 ng/m3 with the mean value of 12.4 ng/m3. Indeno(123-cd)pyrene (IND) and sum of three benzofluoranthene isomers were the most dominant PAH species followed by benzo(ghi)perylene and benzo(a)pyrene (BaP). Using BaP-equivalent approach on the concentration data of carcinogenic PAH species, BaP, and IND contributed the highest carcinogenic exposure equivalent (1.50 and 0.24 ng/m3 on average). A selected number of concentration ratios of specific PAH compounds were calculated to evaluate the possible sources of PAH contamination. The ratios reflected that the major source of PAH compounds in the PM2.5 aerosol fraction of Győr during the study period was fossil fuel combustion from automobiles.

Keywords: air, PM2.5, benzo(a)pyrene, polycyclic aromatic hydrocarbon

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Authors: Mohammadhosein Rahimi, Mohammad Raouf Hosseini, Mehran Bakhshi, Alireza Baghbanan

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Silver ions (Ag⁺) and their compounds are consequentially toxic to microorganisms, showing biocidal effects on many species of bacteria. Silver-phosphate (or silver orthophosphate) is one of these compounds, which is famous for its antimicrobial effect and catalysis application. In the present study, a green method was presented to synthesis silver-phosphate nanoparticles using Sporosarcina pasteurii. The composition of the biosynthesized nanoparticles was identified as Ag₃PO₄ using X-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS). Also, Fourier Transform Infrared (FTIR) spectroscopy showed that Ag₃PO₄ nanoparticles was synthesized in the presence of biosurfactants, enzymes, and proteins. In addition, UV-Vis adsorption of the produced colloidal suspension approved the results of XRD and FTIR analyses. Finally, Transmission Electron Microscope (TEM) images indicated that the size of the nanoparticles was about 20 nm.

Keywords: bacteria, biosynthesis, silver-phosphate, Sporosarcina pasteurii, nanoparticle

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Authors: Shirin jalili, Hadi Shirzad, Mahasti Modarresi, Samaneh Nabavi, Somayeh Khanjani

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Identifying the source tissue of biological material found at crime scenes can be very informative in a number of cases. Despite their usefulness, current visual, catalytic, enzymatic, and immunologic tests for presumptive and confirmatory tissue identification are applicable only to a subset of samples, might suffer limitations such as low specificity, lack of sensitivity, and are substantially impacted by environmental insults. In addition their results are operator-dependent. Recently the possibility of discriminating body fluids using mRNA expression differences in tissues has been described but lack of long term stability of that Molecule and the need to normalize samples for each individual are limiting factors. The use of DNA should solve these issues because of its long term stability and specificity to each body fluid. Cells in the human body have a unique epigenome, which includes differences in DNA methylation in the promoter of genes. DNA methylation, which occurs at the 5′-position of the cytosine in CpG dinucleotides, has great potential for forensic identification of body fluids, because tissue-specific patterns of DNA methylation have been demonstrated, and DNA is less prone to degradation than proteins or RNA. Previous studies have reported several body fluid-specific DNA methylation markers.The presence or absence of a methyl group on the 5’ carbon of the cytosine pyridine ring in CpG dinucleotide regions called ‘CpG islands’ dictates whether the gene is expressed or silenced in the particular body fluid. Were described methylation patterns at tissue specific differentially methylated regions (tDMRs) to be stable and specific, making them excellent markers for tissue identification. The results demonstrate that methylation-based tissue identification is more than a proof-of-concept. The methodology holds promise as another viable forensic DNA analysis tool for characterization of biological materials.

Keywords: DNA methylation, forensic science, epigenome, tDMRs

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Authors: Anna Drabczyk, Sonia Kudlacik-Kramarczyk, Dagmara Malina, Bozena Tyliszczak, Agnieszka Sobczak-Kupiec

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Nowadays, nano-size materials are very popular group of materials among scientists. What is more, these materials find an application in a wide range of various areas. Therefore constantly increasing demand for nanomaterials including metallic nanoparticles such as silver of gold ones is observed. Therefore, new routes of their preparation are sought. Considering potential application of nanoparticles, it is important to select an adequate methodology of their preparation because it determines their size and shape. Among the most commonly applied methods of preparation of nanoparticles chemical and electrochemical techniques are leading. However, currently growing attention is directed into the biological or biochemical aspects of syntheses of metallic nanoparticles. This is associated with a trend of developing of new routes of preparation of given compounds according to the principles of green chemistry. These principles involve e.g. the reduction of the use of toxic compounds in the synthesis as well as the reduction of the energy demand or minimization of the generated waste. As a result, a growing popularity of the use of such components as natural plant extracts, infusions or essential oils is observed. Such natural substances may be used both as a reducing agent of metal ions and as a stabilizing agent of formed nanoparticles therefore they can replace synthetic compounds previously used for the reduction of metal ions or for the stabilization of obtained nanoparticles suspension. Methods that proceed in the presence of previously mentioned natural compounds are environmentally friendly and proceed without the application of any toxic reagents. Methodology: Presented research involves preparation of silver nanoparticles using selected plant extracts, e.g. artichoke extract. Extracts of natural origin were used as reducing and stabilizing agents at the same time. Furthermore, syntheses were carried out in the presence of additional polymeric stabilizing agent. Next, such features of obtained suspensions of nanoparticles as total antioxidant activity as well as content of phenolic compounds have been characterized. First of the mentioned studies involved the reaction with DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical. The content of phenolic compounds was determined using Folin-Ciocalteu technique. Furthermore, an essential issue was also the determining of the stability of formed suspensions of nanoparticles. Conclusions: In the research it was demonstrated that metallic nanoparticles may be obtained using plant extracts or infusions as stabilizing or reducing agent. The methodology applied, i.e. a type of plant extract used during the synthesis, had an impact on the content of phenolic compounds as well as on the size and polydispersity of obtained nanoparticles. What is more, it is possible to prepare nano-size particles that will be characterized by properties desirable from the viewpoint of their potential application and such an effect may be achieved with the use of non-toxic reagents of natural origin. Furthermore, proposed methodology stays in line with the principles of green chemistry.

Keywords: green chemistry principles, metallic nanoparticles, plant extracts, stabilization of nanoparticles

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Authors: Yixiu Liu, Yunzhou Zhang, Jianning Chi, Hao Chu, Rui Zheng, Libo Sun, Guanghao Chen, Fangtong Zhou

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In the last few years, large-scale person re-identification has attracted a lot of attention from video surveillance since it has a potential application prospect in public safety management. However, it is still a challenging job considering the variation in human pose, the changing illumination conditions and the lack of paired samples. Although the accuracy has been significantly improved, the data dependence of the sample training is serious. To tackle this problem, a new strategy is proposed based on bag of visual words (BoVW) model of designing the feature representation which has been widely used in the field of image retrieval. The local features are extracted, and more discriminative feature representation is obtained by cross-view dictionary learning (CDL), then the assignment map is obtained through k-means clustering. Finally, the BoVW histograms are formed which encodes the images with the statistics of the feature classes in the assignment map. Experiments conducted on the CUHK03, Market1501 and MARS datasets show that the proposed method performs favorably against existing approaches.

Keywords: bag of visual words, cross-view dictionary learning, person re-identification, reranking

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Authors: G. Rajeshwari, V. D. M. Jabez Daniel

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Radio Frequency Identification systems are used for automated identification in various applications such as automobiles, health care and security. It is also called as the automated data collection technology. RFID readers are placed in any area to scan large number of tags to cover a wide distance. The placement of the RFID elements may result in several types of collisions. A major challenge in RFID system is collision avoidance. In the previous works the collision was avoided by using algorithms such as ALOHA and tree algorithm. This work proposes collision reduction and increased throughput through reading enhancement method with tree algorithm. The reading enhancement is done by improving interrogation procedure and increasing the data handling capacity of RFID reader with parallel processing. The work is simulated using Xilinx ISE 14.5 verilog language. By implementing this in the RFID system, we can able to achieve high throughput and avoid collision in the reader at a same instant of time. The overall system efficiency will be increased by implementing this.

Keywords: antenna, anti-collision protocols, data management system, reader, reading enhancement, tag

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Authors: A. Selmi, A. Bettaibi, H. Rahmouni, R. M’nassri, N. Chniba Boudjada, A. Chiekhrouhou, K. Khirouni

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Investigation of magnetic and magnetocaloric properties of Pr₀.₇Ca₀.₃Mn₀.₉M₀.₁O₃ perovskite manganites (M=Cr and Ni) has been carried out. Our compounds were prepared by the conventional solid-state reaction method at high temperatures. Rietveld refinement of X-ray diffraction pattern using FULLPROF method shows that all compounds adopt the orthorhombic structure with Pnma space group. The partial substitution of Mn-site drives the system from charge order state to ferromagnetic one with a Curie temperature T𝒸=150K, 118k and 116K for M=Cr and Ni, respectively. Magnetization measurements versus temperature in a magnetic applied field of 0.05T show that all our samples exhibit a paramagnetic–ferromagnetic transition with decreasing temperature. From M(H) isotherms, we have deduced the magnetic entropy change, which present maximum values of 2.37 J/kg.K and 2.94 J/kg.K, in a magnetic field change of 5T for M=Cr and Ni, respectively.

Keywords: manganites, magnetocaloric, magnetic, refrigeration

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Authors: Jamilah Syafawati Yaacob, Muhammad Aiman Ramli

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Cili padi or Capsicum frutescens is one of capsicum species from nightshade family, Solanaceae. It is famous in Malaysia and is widely used as a food ingredient. Capsicum frutescens also possess vast medicinal properties. The objectives of this study are to determine the most optimum 2,4-D hormone concentration for callus induction from stem explants C. frutescens and the effects of different 2,4-D concentrations on expression of compounds from C. frutescens. Seeds were cultured on MS media without hormones (MS basal media) to yield aseptic seedlings of this species, which were then used to supply explant source for subsequent tissue culture experiments. Stem explants were excised from aseptic seedlings and cultured on MS media supplemented with various concentrations (0.1, 0.3 and 0.5 mg/L) of 2,4-D to induce formation of callus. Fresh weight, dry weight and callus growth percentage in all samples were recorded. The highest mean of dry weight was observed in MS media supplemented with 0.5 mg/L 2,4-D, where 0.4499 ± 0.106 g of callus was produced. The highest percentage of callus growth (16.4%) was also observed in cultures supplemented with 0.5 mg/L 2,4-D. The callus samples were also subjected to HPLC-MS to evaluate the effect of hormone concentration on expression of bio active compounds in different samples. Results showed that caffeoylferuloylquinic acids were present in all samples, but was most abundant in callus cells supplemented with 0.3 & 0.5 mg/L 2,4-D. Interestingly, there was an unknown compound observed to be highly expressed in callus cells supplemented with 0.1 mg/L 2,4-D, but its presence was less significant in callus cells supplemented with 0.3 and 0.5 mg/L 2,4-D. Furthermore, there was also a compound identified as octadecadienoic acid, which was uniquely expressed in callus supplemented with 0.5 mg/L 2,4-D, but absent in callus cells supplemented with 0.1 and 0.3 mg/L 2,4-D. The results obtained in this study indicated that plant growth regulators played a role in expression of secondary metabolites in plants. The increase or decrease of these growth regulators may have triggered a change in the secondary metabolite biosynthesis pathways, thus causing differential expression of compounds in this plant.

Keywords: callus, in vitro, secondary metabolite, 2, 4-Dichlorophenoxyacetic acid

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Authors: Zsolt Szucs, Viktor Kelemen, Son Le Thai, Magdolna Csavas, Erzsebet Roth, Gyula Batta, Annelies Stevaert, Evelien Vanderlinden, Aniko Borbas, Lieve Naesens, Pal Herczegh

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The approval of modern glycopeptide antibiotics such as dalbavancin and oritavancin which have excellent activity against Gram-positive bacteria, encouraged our research group to prepare semisynthetic compounds from several members of glycopeptides by various chemical methods. Derivatives from the aglycone of ristocetin, eremomycin, vancomycin and a pseudoaglycon of teicoplanin have been synthesized in a systematic manner. Interestingly, some of the aglycoristocetin derivatives displayed noteworthy anti-influenza activity. More recently our group has been focusing on the modifications of one of the pseudoaglycons of teicoplanin. The reaction of N-ethoxycarbonyl maleimide derivatives with the primary amino function, the copper-catalysed azide-alkyne click reaction and the sulfonylation of the N-terminus were utilized to obtain systematic series of compounds. All substituents provide a more lipophilic character to the new molecules compared to the parent antibiotics, which is known to be favourable for activity against resistant bacteria. Lipoglycopeptides are also known to have antiviral properties, which has been predominantly studied on HIV by others. The structure-activity relationship study of our compounds revealed the influence of a few structural elements on biological activity. In many cases, minimal changes in lipophilicity and structure produced great differences in efficacy and cytotoxicity. In vitro experiments showed that these compounds are not only active against glycopeptide resistant Gram-positive bacteria but in several cases they prevent the infection of cell cultures by different strains of influenza viruses. This is probably related to the inhibition of the viral entry into the host cell nucleus, of which the exact mechanism is unknown. In some instances, reasonably low concentrations were sufficient to observe this effect. Several derivatives were highly cytotoxic at the same time, but some of them displayed a good selectivity index. The antiviral properties of the compounds are not restricted to influenza viruses e.g., some of them showed good activity against Human Coronavirus 229E. This work could potentially lead to the development of antiviral drugs which possess the crucial structural motifs that are needed for antiviral activity, while missing those which contribute to the antibacterial effect.

Keywords: antiviral, glycopeptide, semisynthetic, teicoplanin

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Authors: G. Scremin, I. Y. Suh, S. Doukas

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Spectators follow their favorite sports teams for different reasons. While some attend a sporting event simply for its entertainment value, others do so because of the personal sense of achievement and accomplishment their connection with a sports team creates. Moreover, the level of identity spectators feel toward their favorite sports team falls in a broad continuum. Some are mere spectators. For those spectators, their association to a sports team has little impact on their self-image. Others are die-hard fans who are proud of their association with their team and whose connection with that team is an important reflection of who they are. Several motives for sports consumption can be used to explain the level of spectator support in a variety of sports. Those motives can also be used to explain the variance in the identification, attachment, and loyalty spectators feel toward their favorite sports team. Motives for sports consumption can be used to discriminate the degree of identification spectators have with their favorite sports team. In this study, motives for sports consumption was used to discriminate the level of identity spectators feel toward their sports team. It was hypothesized that spectators with a strong level of team identity would report higher rates of interest in player, interest in sports, and interest in team than spectators with a low level of team identity. And spectators with a low level of team identity would report higher rates for entertainment value, bonding with friends or family, and wholesome environment. Football spectators in the United States and England were surveyed about their motives for football consumption and their level of identification with their favorite football team. To assess if the motives of sports fans differed by level of team identity and allegiance to an American or English football team, a Multivariate Analysis of Variance (MANOVA) under the General Linear Model (GLM) procedure found in SPSS was performed. The independent variables were level of team identity and allegiance to an American or English football team, and the dependent variables were the sport fan motives. A tripartite split (low, moderate, high) was used on a composite measure for team identity. Preliminary results show that effect of team identity is statistically significant (p < .001) for at least nine of the 17 motives for sports consumption assessed in this investigation. These results indicate that the motives of spectators with a strong level of team identity differ significantly from spectators with a low level of team identity. Those differences can be used to discriminate the degree of identification spectators have with their favorite sports team. Sports marketers can use these methods and results to develop identity profiles of spectators and create marketing strategies specifically designed to attract those spectators based on their unique motives for consumption and their level of team identification.

Keywords: fan identification, market segmentation of sports fans, motives for sports consumption, team identity

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Authors: Muhammad Abdullah, Salman Iqbal, Mamoona Rasheed

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Social identity among people is an important source of pride and self-esteem, consequently, people struggle to preserve a positive perception of their groups and collectives. The purpose of this paper is to explain the process of social identification and to highlight the underlying causal factors of social identity among employees. There is a little research about how the social identity of employees is shaped in Pakistan’s organizational culture. This study is based on social identity theory. This study uses Systems’ approach as a research methodology. The feedback loop approach is applied to explain the underlying key elements of employee behavior that collectively form social identity among social groups in corporate arena. The findings of this study reveal that effective, evaluative and cognitive components of an individual’s personality are associated with the social identification. The system dynamic feedback loop approach has revealed the underlying structure that is associated with social identity, social group formation, and effective component proved to be the most associated factor. This may also enable to understand how social groups become stable and individuals act according to the group requirements. The value of this paper lies in the understanding gained about the underlying key factors that play a crucial role in social group formation in organizations. It may help to understand the rationale behind how employees socially categorize themselves within organizations. It may also help to design effective and more cohesive teams for better operations and long-term results. This may help to share knowledge among employees as well. The underlying structure behind the social identification is highlighted with the help of system modeling.

Keywords: affective commitment, cognitive commitment, evaluated commitment, system thinking

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Authors: Reza Mehrafarin, Nafiseh Mirshekari

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The Sistan plain has always been a site for the settlement of various human societies, thanks to its favorable environmental conditions, such as abundant water from the Hirmand River and fertile sedimentary soil. Consequently, there was a need for a systematic archaeological investigation in the area. The survey had multiple objectives, with the most significant ones being the creation of an archaeological map and the identification and documentation of all ancient sites to establish their records and chronology. The survey was carried out in two phases, with each phase covering half of the area. The research method involved fieldwork, with two teams of professional archaeologists conducting a comprehensive survey of each of the 22 areas in Sistan. Once an area was identified, various recording, scientific, and field operations were executed to study the site. In the first phase (2007), an intensive field survey focused on the residential area of Sistan, including its northern and eastern regions. This phase resulted in the identification of 808 sites in eleven selected areas. In the second phase (2009), the desert area of Sistan, or its southern half, was surveyed, leading to the identification of approximately 853 sites. Overall, these surveys resulted in the identification of 1661 sites in Sistan. Among these sites, approximately 899 belong to the Bronze Age (late 4th millennium BCE to early 2nd millennium BCE). Of these sites, around 501 date back to the historical period, while nearly 590 sites pertain to the Islamic period. The archaeological investigations of both phases revealed that Sistan has consistently possessed fertile soil, abundant water, and a skilled workforce, making it capable of becoming Iran's granary and the center of the East once again if these conditions are restored.

Keywords: sistan, field surveys, archaeology, archaeological map

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Authors: Houneïda Benbouzid, Houria Berrebbah, Mohammed-Réda Djebar

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The toxicological impacts of the increasing number of synthetic compounds present in the aquatic environment are assessed predominantly in laboratory studies where test organisms are exposed to a range of concentrations of single compounds. The bio-indicator Paramecium sp., characterized by a short life cycle, rapid multiplication and normal behavior that may be affected by the presence of pollutants. We therefore investigated the inhibitory effect of a newly synthesized acaricide: the chlorfenapyr tested at concentrations of 250, 300, and 350 µM on a pure culture of Paramecium sp. during 6 day. Paramecia treated with different concentrations of Chlorfenapyr illustrate strong inhibition of cell growth from the second day of treatment. Low levels of glutathione, increased glutathione S-transferase and the decrease in respiratory metabolism, recorded in the presence of different concentrations of Chlorfenapyr, involve the activation of detoxification system.

Keywords: Paramecium sp., chlorfenapyr, oxidative enzymes, detoxification

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Authors: Isari Pairoa, Proud Arunrangsiwed

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Celebrity and brand mascot endorsement have been explored for more than three decades. Both endorsers can effectively transfer their reputation to corporate image and can influence the customers to purchase the product. However, there was little known about the mediators between the level of endorsement and its effect on buying behavior. The objective of the current study is to identify the gab of the previous studies and to seek possible mediators. It was found that consumer’s memory and identification are the mediators, of source credibility and endorsement effect. A future study should confirm the model of endorsement, which was established in the current study.

Keywords: product endorsement, memory, identification theory, source credibility, unintentional effect

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Authors: Florence Malongane, Lyndy J. McGaw, Legesse K. Debusho, Fhatuwani N. Mudau

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Rooibos (Aspalathus linearis (Burm.f.) R.Dahlgren), honeybush (Cyclopia Vent. species), bush tea (Athrixia phylicoides DC.) and special tea (Monsonia burkeana) are traditionally consumed herbal teas in South Africa. The volatile and sensory qualities of rooibos and honeybush tea have previously been described although there is a dearth of information regarding the sensory attributes and volatile compounds analysis of special tea and bush tea. The objective of this study was to describe the sensory properties, compare the differences in descriptive sensory analysis (DSA) and volatile compounds of bush tea, special, rooibos, honeybush and the blend of bush tea with special, honeybush and rooibos in a 1:1 ratio and subsequently to determine the influence of blending bush tea with other herbal teas. DSA was used to assess the sensory attributes of the teas while gas chromatography–mass spectrometry (GC-MS) was used to quantitatively determine the volatile components of the teas. Rooibos tea and honeybush tea had an overall sweet-caramel, honey-sweet, perfume floral and woody aroma with slight astringency, consistent with the taste and aftertaste attributes. In contrast, bush tea and special tea depicted green-cut grass, dry green herbal, cooked spinach aroma as well as taste and aftertaste characteristics. GC-MS analyses revealed that the seven tea samples had similar major volatiles, including 2-furanmethanol, 2-methoxy-4-vinylphenol, acetic acid, D-limonene terpene and phytol. Cluster analysis revealed that the sweet and woody flavour of honeybush and rooibos were ascribed to the presence of á-myrcene, phenylethyl alcohol, phytol and vanillin. The bitter, medicinal flavour attributes of special tea were attributed to (-)-carvone. Blending of bush tea with rooibos and honeybush tea toned down its aversive flavour components, typically the bitter, green-cut grass and herbal properties, thus minimising the possibility of consumer aversion.

Keywords: bush tea, rooibos tea, honeybush tea, sensory, volatile compounds

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Authors: Hacer Sule Gonul, Vedat Uyak

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Intensive use of pesticides in agricultural activity causes mixing of these compounds into water sources with surface flow. Especially after the 1970s, a number of limitations imposed on the use of chlorinated pesticides that have a carcinogenic risk potential and regulatory limit have been established. These chlorinated pesticides discharge to water resources, transport in the water and land environment and accumulation in the human body through the food chain raises serious health concerns. Carbon nanotubes (CNTs) have attracted considerable attention from on all because of their excellent mechanical, electrical, and environmental characteristics. Due to CNT particles' high degree of hydrophobic surfaces, these nanoparticles play critical role in the removal of water contaminants of natural organic matters, pesticides and phenolic compounds in water sources. Health concerns associated with chlorinated pesticides requires the removal of such contaminants from aquatic environment. Although the use of aldrin and atrazine was restricted in our country, repatriation of illegal entry and widespread use of such chemicals in agricultural areas cause increases for the concentration of these chemicals in the water supply. In this study, the compounds of chlorinated pesticides such as aldrin and atrazine compounds would be tried to eliminate from drinking water with carbon nanotube adsorption method. Within this study, 2 different types of CNT would be used including single-wall (SWCNT) and multi-wall (MWCNT) carbon nanotubes. Adsorption isotherms within the scope of work, the parameters affecting the adsorption of chlorinated pesticides in water are considered as pH, contact time, CNT type, CNT dose and initial concentration of pesticides. As a result, under conditions of neutral pH conditions with MWCNT respectively for atrazine and aldrin obtained adsorption capacity of determined as 2.24 µg/mg ve 3.84 µg/mg. On the other hand, the determined adsorption capacity rates for SWCNT for aldrin and atrazine has identified as 3.91 µg/mg ve 3.92 µg/mg. After all, each type of pesticide that provides superior performance in relieving SWCNT particles has emerged.

Keywords: pesticide, drinking water, carbon nanotube, adsorption

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Authors: K. Alese Boniface, K. Adu Michael

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Cybercrime is now becoming a big challenge in Nigeria apart from the traditional crime. Inability to identify perpetrators is one of the reasons for the growing menace. This paper proposes a design for monitoring internet users’ activities in order to curbing cybercrime. It requires redefining the operations of Internet Service Providers (ISPs) which will now mandate users to be authenticated before accessing the internet. In implementing this work which can be adapted to a larger scale, a virtual router application is developed and configured to mimic a real router device. A sign-up portal is developed to allow users to register with the ISP. The portal asks for identification information which will include bio-data and government issued identification data like National Identity Card number, et cetera. A unique username and password are chosen by the user to enable access to the internet which will be used to reference him to an Internet Protocol Address (IP Address) of any system he uses on the internet and thereby associating him to any criminal act related to that IP address at that particular time. Questions such as “What happen when another user knows the password and uses it to commit crime?” and other pertinent issues are addressed.

Keywords: cybercrime, sign-up portal, internet service provider (ISP), internet protocol address (IP address)

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Authors: Yuri V. Kim

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This article presents a new approach to the Functional Testing of Space Systems (SS). It can be considered as a generic test and used for a wide class of SS that from the point of view of System Dynamics and Control may be described by the ordinary differential equations. Suggested methodology is based on using semi-natural experiment- laboratory stand that doesn’t require complicated, precise and expensive technological control-verification equipment. However, it allows for testing system as a whole totally assembled unit during Assembling, Integration and Testing (AIT) activities, involving system hardware (HW) and software (SW). The test physically activates system input (sensors) and output (actuators) and requires recording their outputs in real time. The data is then inserted in laboratory PC where it is post-experiment processed by Matlab/Simulink Identification Toolbox. It allows for estimating system dynamics in form of estimation of system differential equations by the experimental way and comparing them with expected mathematical model prematurely verified by mathematical simulation during the design process.

Keywords: system dynamics, space system ground tests and space qualification, system dynamics identification, satellite attitude control, assembling, integration and testing

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Authors: Pasquale Porcu, Mireille Vonlanthen, Gerardo Zaragoza-Galán, Ernesto Rivera

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In this work, we report the synthesis of a novel series of dendritic molecules bearing donor-acceptor groups (pyrene-bodipy) with potential applications in energy transfer. Initially, first and second generation Fréchet type dendrons (Py2-G1OH and Py4-G2OH) were prepared from 1-pyrenylbutanol and 3,5-dihydroxybenzylic alcohol. These compounds were further linked to a bodipy unit via an esterification reaction in order to obtain the desired products (Bodipy-G1Py2) and Bodipy-G2Py4). These compounds were fully characterized by FTIR and 1H and 13C NMR spectroscopy and their molecular weights were determined by MALDITOF. The optical and photophysical properties of these molecules were evaluated by absorbance and fluorescence spectroscopy, in order to compare their behaviour with other analogue molecules.

Keywords: bodipy, dendritic molecules, optical properties, pyrene

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Authors: Abdol-Hassan Doulah

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In this research, some of the inorganic complexes of uranyl with N- donor ligands were synthesized. Complexes were characteriezed by FT-IR and UV spectra, ¹HNMR, ¹³CNMR and some physical properties. The uranyl unit (UO2) is composed of a center of uranium atom with the charge (+6) and two oxygen atom by forming two U=O double bonds. The structure is linear (O=U=O, 180) and usually stable. So other ligands often coordinate to the U atom in the plane perpendicularly to the O=U=O axis. The antitumor activity of some of ligand and their complexes against a panel of human tumor cell lines (HT29: Haman colon adenocarcinoma cell line T47D: human breast adenocarcinoma cell line) were determined by MTT(3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) assay. These data suggest that some of these compounds provide good models for the further design of potent antitumor compounds.

Keywords: inorganic, uranyl complex-donor ligands, Schiff bases, anticancer activity

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Authors: Timir Baran Roy, Luis Guerreiro, Ashutosh Bagchi

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Dynamic study is important in order to design, repair and rehabilitation of structures. It has played an important role in the behavior characterization of structures; such as bridges, dams, high-rise buildings etc. There had been a substantial development in this area over the last few decades, especially in the field of dynamic identification techniques of structural systems. Frequency Domain Decomposition (FDD) and Time Domain Decomposition are most commonly used methods to identify modal parameters; such as natural frequency, modal damping, and mode shape. The focus of the present research is to study the dynamic characteristics of typical timber masonry walls commonly used in Portugal. For that purpose, a multi-storey structural prototypes of such walls have been tested on a seismic shake table at the National Laboratory for Civil Engineering, Portugal (LNEC). Signal processing has been performed of the output response, which is collected from the shaking table experiment of the prototype using accelerometers. In the present work signal processing of the output response, based on the input response has been done in two ways: FDD and Stochastic Subspace Identification (SSI). In order to estimate the values of the modal parameters, algorithms for FDD are formulated, and parametric functions for the SSI are computed. Finally, estimated values from both the methods are compared to measure the accuracy of both the techniques.

Keywords: frequency domain decomposition (fdd), modal parameters, signal processing, stochastic subspace identification (ssi), time domain decomposition

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Authors: F. Asadi, M. M. Zerafat, S. Sabbaghi

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Among water pollutants, volatile organic compounds can cause severe long lasting effects not only on biotic organism but also on human health. As a result, this material group has attracted more attention in recent years. Adsorption is one of the common processes for remediation of aromatic compounds. In this study, porous clay hetrostructers (PCHs) are synthesized through gallery template approach and cetyltrimethylammonium bromide and dodecylamine used as template and co-template, respectively. Porous clay is characterized by XRD and FTIR. Batch adsorption experiments were carried out to investigate the effect of various adsorption parameters like adsorbent dosage, pH, initial concentration and contact time. It was found that by increasing adsorbent dosage from 0.5gr/lit to 4gr/lit, toluene removal is increased from 34% to 88.1%. Increasing contact time and decreasing the pH of aqueous solution increases toluene removal efficiency.

Keywords: adsorption, clay, nano-porous, toluene

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Authors: Mohsen Farhadloo, Majid Farhadloo

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Aspect-level opinion mining that aims at discovering aspects (aspect identification) and their corresponding ratings (sentiment identification) from customer reviews have increasingly attracted attention of researchers and practitioners as it provides valuable insights about products/services from customer's points of view. Instead of addressing aspect identification and sentiment identification in two separate steps, it is possible to simultaneously identify both aspects and sentiments. In recent years many graphical models based on Latent Dirichlet Allocation (LDA) have been proposed to solve both aspect and sentiment identifications in a single step. Although LDA models have been effective tools for the statistical analysis of document collections, they also have shortcomings in addressing some unique characteristics of opinion mining. Our goal in this paper is to address one of the limitations of topic models to date; that is, they fail to directly model the associations among topics. Indeed in many text corpora, it is natural to expect that subsets of the latent topics have higher probabilities. We propose a probabilistic graphical model called focus-LDA, to better capture the associations among topics when applied to aspect-level opinion mining. Our experiments on real-life data sets demonstrate the improved effectiveness of the focus-LDA model in terms of the accuracy of the predictive distributions over held out documents. Furthermore, we demonstrate qualitatively that the focus-LDA topic model provides a natural way of visualizing and exploring unstructured collection of textual data.

Keywords: aspect-level opinion mining, document modeling, Latent Dirichlet Allocation, LDA, sentiment analysis

Procedia PDF Downloads 94