Search results for: secondary compounds

Authors: M. S. M. Yusof, R. Ramli, S. K. C. Soh, N. Ismail, N. Ngah

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This study presents the synthesis of a series of methoxybenzoylthiourea amino acid derivatives. The compounds were obtained from the reactions between 2/3/4-methoxybenzoyl isothiocyanate with threonine. All of the compounds were characterized via mass spectrometry, ¹H and ¹³C NMR spectrometry, UV-Vis spectrophotometer and FT-IR spectroscopy. Mass spectra for all of the compounds showed the presence of molecular ion [M]⁺ peaks at m/z 312, which are in agreement to the calculated molecular weight. For ¹H NMR spectra, the presence of OCH₃, C=S-NH and C=O-NH protons were observed within range of δ_H 3.8-4.0 ppm, 11.1-11.5 ppm and 10.0-11.5 ppm, respectively. ¹³C NMR spectra in all compounds displayed the presence of OCH₃, C=O-NH, C=O-OH and C=S carbon resonances within range of δ_C 55.0-57.0 ppm, 165.0-168.0 ppm, 170.0-171.0 ppm and 180.0-182.0 ppm, respectively. In UV spectra, two absorption bands have been observed and both were assigned to the n-π* and π-π* transitions. Six vibrational modes of v(N-H), v(O-H), v(C=O-OH), v(C=O-NH), v(C=C) aromatic and v(C=S) appeared in the FT-IR spectra within the range of 3241-3467 cm^-1, 2976-3302 cm^-1, 1720-1768 cm^-1, 1655-1672 cm^-1, 1519-1525 cm^-1 and 754-763 cm^-1, respectively. The antibacterial activity for all of the compounds was screened against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella typhimurium and Escherichia coli. However, no activity was observed.

Keywords: methoxybenzoyl isothiocyanate, amino acid, threonine, antibacterial

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Authors: Marcela Dvorakova, Lenka Langhansova, Premysl Landa

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A series of quinazoline derivatives bearing aromatic rings in 2- and 4-positions were prepared and tested for their biological activity. Firstly, the compounds were evaluated for their potential to inhibit various kinases, such as autophagy activating kinase ULK1, 3-Phosphoinositide-dependent kinase 1, and TANK-binding kinase 1. None of the compounds displayed any activity on these kinases. Secondly, the compounds were tested for their anti-inflammatory activity expressed as cyclooxygenase (COX) isoforms and 5-lipoxygenase (5-LOX) inhibition. Three of the compounds showed significant selectivity towards COX-1 isoform (COX-2/COX-1 SI = 20-30). They inhibited COX-1 in a single-digit µM range. There was also one compound that exhibited inhibitory activity towards all three tested enzymes in µM range (IC50COX-1 = 1.9 µM; IC50COX-2 and 5-LOX = 10.1µM. COX-1 inhibition was until recently considered undesirable due to COX-1 constitutive expression in most cell types and tissues. Thus, there are not many compounds known with selective COX-1 activity. However, it is now believed that COX-1 plays an important role in the pathophysiology of several acute and chronic disorders, including cancer or neurodegenerative diseases. Thus, the discovery of effective COX-1 selective inhibitors is desirable and important.

Keywords: cyclooxygenases, kinases, lipoxygenases, quinazolines

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Authors: Abdel Rahman Altakhaineh, Mohamma Alaghawat, Hiba Alhendi

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This paper reports an investigation of the comprehension of English compound nouns by sixty Arabic-speaking English Foreign Language (EFL) learners majoring in English at the University of Jordan, Amman. The investigation focused on the problems that these learners may encounter in understanding certain types of compounds and their ability to use their L1 compound noun knowledge to produce the meaning of L2 compound nouns. Participants whose English proficiency level was advanced underwent a test to identify the meaning ofan underlined compound without using a dictionary. Theresponses to the three different types of compounds were analyzed usingTwo-Way repeated measures ANOVA, and the results showed that there were different endocentric and exocentric compound responses within subordinative compounds, with a statistically significant difference between the two in favor of endocentric compounds. We argue that the endocentric, especially subordinative endocentric compounds,weremore easily understood due to its representative nature, i.e., because the head represents the meaning of the whole compound. The study concludes with pedagogical implications for teaching compound nouns.

Keywords: morphology, compounding, SLA, arabic-speaking EFL learners

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Authors: A. Kellou, L. Rouaiguia, L. Rabahi

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In the present work, the atomic hydrogen absorption trend in the GdNi5 and GdNi4Cu rare earth compounds within the hexagonal CaCu5 type of crystal structure (space group P6/mmm) is investigated. The density functional theory (DFT) combined with the generalized gradient approximation (GGA) is used to study the site preference of atomic hydrogen at 0K. The octahedral and tetrahedral interstitial sites are considered. The formation energies and structural properties are determined in order to evaluate hydrogen effects on the stability of the studied compounds. The energetic diagram of hydrogen storage is established and compared in GdNi5 and GdNi4Cu. The magnetic properties of the selected compounds are determined using spin polarized calculations. The obtained results are discussed with and without hydrogen addition taking into account available theoretical and experimental results.

Keywords: density functional theory, hydrogen storage, rare earth compounds, structural and magnetic properties

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Authors: Sylvain Caillol, Ghislain David

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Phenolic resins are industrially used in a wide range of applications from commodity and construction materials to high-technology aerospace industry. They are mainly produced from the reaction between phenolic compounds and formaldehyde. Nevertheless, formaldehyde is a highly volatile and hazardous compound, classified as a Carcinogenic, Mutagenic and Reprotoxic chemical (CMR). Vanillin is a bio-based and non-toxic aromatic aldehyde compound obtained from the abundant lignin resources. Also, its aromaticity is very interesting for the synthesis of phenolic resins with high thermal stability. However, because of the relatively low reactivity of its aldehyde function toward phenolic compounds, it has never been used to synthesize phenolic resins. We developed innovative functionalization reactions and designed new bio-based aromatic aldehyde compounds from vanillin. Those innovative compounds present improved reactivity toward phenolic compounds compared to vanillin. Moreover, they have target structures to synthesize highly cross-linked phenolic resins with high aromatic densities. We have obtained phenolic resins from substituted vanillin, thus without the use of any aldehyde compound classified as CMR. The analytical tests of the cured resins confirmed that those bio-based resins exhibit high levels of performance with high thermal stability and high rigidity properties

Keywords: phenolic resins, formaldehyde-free, vanillin, bio-based, non-toxic

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Authors: Tabussam Tufail

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Purpose: The core purpose of the current review article is to elaborate the phytochemicals present in turnip (brassica rapus l.) and also allied health claims. Plant-based foods contain a significant amount of bioactive compounds which provide desirable health benefits beyond the basic nutrition. Epidemiological evidence suggests that consumption of a diet rich in vegetables and fruits has positive implications for human health. Design: Potential of turnip peroxidase (TP) for the treatment of phenolic-contaminated solutions has been reviewed. However, issues of taste along with behavioral nutrition ought to be considered. So in the last decades, special attention has been paid towards edible plants, especially those that are rich in secondary metabolites (frequently called phytochemicals) and nowadays, there is an increasing interest in the antioxidant activity of such phytochemicals present in the diet. These chemicals favor nutritional and phytotherapy that is emerging as new concepts of health aid in recent years. Turnip is rich in these valuable ingredients though it can be employed as having health promoting and healing properties. Findings: Numerous bioactive components i.e. organic acids, phenolic compounds, turnip peroxidase, kaempeferol, vitamin-K, etc. are present in turnip. The review focused on the significance of plant derived (especially turnip) phenolic compounds as a source of certain beneficial compounds for human health. Owing to the presence of bioactive moieties, the turnip has high antioxidant activity, positive role in blood clotting, effectual in phenobarbital-induced sleeping time, effective against hepatic injury in diabetics and also have a good hepatoprotective role. Strong recommendations for consumption of nutraceuticals from turnip have become progressively popular to improve health, and to prevent from diseases.

Keywords: phytochemicals, turnip, antioxidants, health benefits

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Authors: Sidra Rizwan

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The article focuses on the training needs of secondary school teachers related to the knowledge component of instructional planning and strategies as stated in the National professional standards for teachers in Pakistan. The study aimed to determine the training needs of secondary school teachers on different aspects of knowledge & understanding component of instructional planning and strategies. The target population of the study was the secondary school teachers across Pakistan. For this purpose, a sample of 400 secondary school teachers was selected through multistage sampling from all the four provinces and Federal capital area. Survey method was adopted to assess the training needs by using a self reporting tool. The tool helped to gauge the training needs through indirect inventory questions as well as a ranking list in which the respondents themselves prioritized their training areas. The results showed variation between the direct and indirect reporting of the teachers on the basis of which it was concluded that the secondary school teachers needed awareness about the knowledge component of instructional planning and strategies in order to redefine their actual training needs. The researcher further identified the training needs of secondary school teachers within each province and Islamabad capital territory; including an analysis of variations between strata. As teachers are considered agents of change, their training according to the professional standards should provide a solid base for “rethinking education”.

Keywords: training needs, secondary school teachers, instructional planning & strategies, knowledge & understanding

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Authors: Ali Aghazadegan, Ali Shokri, Julia Mullarney

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River confluences are areas where there is a lot of mixing, which is often caused by the formation of shear layers and helical motions. The hydrodynamics of secondary circulation at river confluences with low flow discharge ratios and a 90° junction angle are investigated in this study. The analysis is based on Delft 3D modelling, which includes a three-dimensional time-averaged velocity field, turbulence, and water surface levels that have been validated using laboratory data. Confluence structure was characterized by shear layer, secondary circulation, and mixing at the junction and post confluence channel. This study analysis formation of the shear layer by generation of secondary circulations in variation discharge ratios. The values of streamwise, cross-wise, and vertical components are used to estimate the secondary circulation observed within and downstream of the tributary mouth. These variables are estimated for three horizontal planes at Z = [0.14; 0.07; 0.02] and for eight cross-sections at X = [-0.1; 0.00; 0.10; 0.2; 0.30; 0.4; 0.5; 0.6] within a range of 0.05 Y 0.30.

Keywords: river confluence, shear layer, secondary circulation, hydrodynamics

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Authors: Prashant K. Sharma, Kavita Shah

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In recent years, the photochemistry of nanomagnetic particles is being utilized for the removal of various pollutants. In the current era where large quantities of various xenobiotic compounds are released in the environment some of which are highly toxic are being used routinely by industries and consumers. Extensive use of these chemicals provides greater risk to plants, animals and human population which has been reviewed from time to time. Apart from the biological degradation, photochemical removal holds considerable promise for the abatement of these pesticides in wastewaters. This paper reviews the photochemical removal of xenobiotic compounds. It is evident from the review that removal depends on several factors such as pH of the solution, catalysts loading, initial concentration, light intensity and so on and so forth. Since the xenobiotics are ubiquitously present in the wastewaters, photochemical technology seems imperative to alleviate the pollution problems associated with the xenobiotics. However, commercial application of this technology has to be clearly assessed.

Keywords: magnetic, nanoparticles, photocatalayst, xenobiotic compounds

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Authors: Nasser Marshad Alzeer

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This study examines the spatial distribution of secondary schools in Riyadh. It considers both public girls and boys sector provision and assesses the efficiency of the spatial distribution of secondary schools. Since the establishment of the Ministry of Education (MOE) in 1953 and General Presidency for Female Education, (GPFE) in 1960, there has been a great expansion of education services in Saudi Arabia, particularly during the 1980s. However, recent years have seen much slower rates of increase in the public education sector but the population continues to grow rapidly. This study investigates the spatial distribution of schools through the use of questionnaire surveys and applied GIS. Overall, the results indicate a shortage of public secondary schools, especially in the north of the city. It is clear that there is overcrowding in the majority of secondary schools. The establishment of new schools has been suggested to solve the problem of overcrowding. A number of socio-economic and demographic factors are associated with differences in the utilization of the public secondary schools. A GIS was applied in this study in order to assess the spatial distribution of secondary schools including the modification of existing catchment area boundaries and locating new schools. This modification could also reduce the pupil pressure on certain schools and further benefits could probably be gained.

Keywords: analysis, distribution, Saudi, GIS, schools

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Authors: Yener Tekeli, Hayri Baba

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The natural active compounds found in medicinal plants are belong to various chemical structures including polyphenolic compounds, flavonoids, essential oils, and vitamins and some of these compounds have anticancer, antioxidant, and antimicrobial activity. However, these compounds have been little known about mechanisms to confer antibacterial drug resistance. In this study; some macrofungi extracts (Pholiota lucifera, Gnaoderma applanatum and Pleurotus ostreatus) were investigated for their abilities to enhance bacterial permeability by flow cytometry. This experiments exhibited enhancement of these extracts to disrupt the cytoplasmic membrane of living bacterial (Listeria innocua and Escherichia coli) cells. These experiments were designed to detect uptake of PI&SYT by enhancing with a ranged concentration of herb extracts.

Keywords: antimicrobial activity, flow cytometry, macrofungi, multidrug resistant

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Authors: Ferhat Mohamed, Boukhatem Mohamed Nadjib, Chemat Farid

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Simultaneous distillation–extraction (SDE) is routinely used by analysts for sample preparation prior to gas chromatography analysis. In this work, a new process design and operation for microwave assisted simultaneous distillation – solvent extraction (MW-SDE) of volatile compounds was developed. Using the proposed method, isolation, extraction and concentration of volatile compounds can be carried out in a single step. To demonstrate its feasibility, MW-SDE was compared with the conventional technique, Simultaneous distillation–extraction (SDE), for gas chromatography-mass spectrometry (GC-MS) analysis of volatile compounds in a fresh orange juice and a dry spice “carvi seeds”. SDE method required long time (3 h) to isolate the volatile compounds, and large amount of organic solvent (200 mL of hexane) for further extraction, while MW-SDE needed little time (only 30 min) to prepare sample, and less amount of organic solvent (10 mL of hexane). These results show that MW-SDE–GC-MS is a simple, rapid and solvent-less method for determination of volatile compounds from aromatic plants.

Keywords: essential oil, extraction, distillation, carvi seeds

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Authors: Morteza Taherinezhad, Ahmad Reza Rabbani, Morteza Asemani, Rudy Swennen

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Oil-oil correlation is one of the most important issues in geochemical studies that enables to classify oils genetically. Oil-oil correlation is generally estimated based on non-polar fractions of crude oil (e.g., saturate and aromatic compounds). Despite several advantages, the drawback of using these compounds is their susceptibility of being affected by secondary processes. The polar fraction of crude oil (e.g., asphaltenes) has similar characteristics to kerogen, and this structural similarity is preserved during migration, thermal maturation, biodegradation, and water washing. Therefore, these structural characteristics can be considered as a useful correlation parameter, and it can be concluded that asphaltenes from different reservoirs with the same genetic signatures have a similar origin. Hence in this contribution, an integrated study by using both non-polar and polar fractions of oil was performed to use the merits of both fractions. Therefore, five oil samples from oil fields in the Persian Gulf were studied. Structural characteristics of extracted asphaltenes were investigated by Fourier transform infrared (FTIR) spectroscopy. Graphs based on aliphatic and aromatic compounds (predominant compounds in asphaltenes structure) and sulphoxide and carbonyl functional groups (which are representatives of sulphur and oxygen abundance in asphaltenes) were used for comparison of asphaltenes structures in different samples. Non-polar fractions were analyzed by GC-MS. The study of asphaltenes showed the studied oil samples comprise two oil families with distinct genetic characteristics. The first oil family consists of Salman and Reshadat oil samples, and the second oil family consists of Resalat, Siri E, and Siri D oil samples. To validate our results, biomarker parameters were employed, and this approach completely confirmed previous results. Based on biomarker analyses, both oil families have a marine source rock, whereby marl and carbonate source rocks are the source rock for the first and the second oil family, respectively.

Keywords: biomarker, non-polar fraction, oil-oil correlation, petroleum geochemistry, polar fraction

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Authors: Ellen A. Kalinga

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Moodle is an open source learning management system that enables creation of a powerful and flexible learning environment. Many organizations, especially learning institutions have customized Moodle open source LMS for their own use. In general open source LMSs are of great interest due to many advantages they offer in terms of cost, usage and freedom to customize to fit a particular context. Tanzania Secondary School e-Learning (TanSSe-L) system is the learning management system for Tanzania secondary schools. TanSSe-L system was developed using a number of methods, one of them being customization of Moodle Open Source LMS. This paper presents few areas on the way Moodle OS LMS was customized to produce a functional TanSSe-L system fitted to the requirements and specifications of Tanzania secondary schools’ context.

Keywords: LMS, Moodle, e-learning, Tanzania, secondary school

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Authors: Rasha S. Kamal, Nehal S. Ahmed, Amal M. Nassar, Nour E. A. Abd El-Sattar

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In the present work, some lube oil antioxidants based on ester of some aromatic thiourea derivative were prepared by two steps: the first step is the reaction of succinyl chloride with ammonium thiocyanate in addition to anthranilic acid as three component system to prepare thiourea derivative (A); the second step is esterification of compound (A) by different alcohol (decyl C₁₀, tetradecyl C₁₄, and octadecyl C₁₈) alcohol. The structures of the prepared compounds were confirmed by infra-red spectroscopy, nuclear magnetic resonance, elemental analysis and determination of the molecular weights. All the prepared compounds were soluble in lube oil. The efficiency of the prepared compounds as antioxidants lube oil additives was investigated and it was found that these prepared compounds give good result as lube oil antioxidant.

Keywords: antioxidant lube oil, three component system, aromatic thiourea derivatives, esterification

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Authors: Dewi Selvia Fardhyanti, Astrilia Damayanti

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Coal tar is a liquid by-product of the process of coal gasification and carbonation, also in some industries such as steel, power plant, cement, and others. This liquid oil mixture contains various kinds of useful compounds such as aromatic compounds and phenolic compounds. These compounds are widely used as raw material for insecticides, dyes, medicines, perfumes, coloring matters, and many others. This research investigates thermodynamic modelling of liquid-liquid equilibria (LLE) in solvent extraction of o-Cresol from the coal tar. The equilibria are modeled by ternary components of Wohl, Van Laar, and Three-Suffix Margules models. The values of the parameters involved are obtained by curve-fitting to the experimental data. Based on the comparison between calculated and experimental data, it turns out that among the three models studied, the Three-Suffix Margules seems to be the best to predict the LLE of o-Cresol for those system.

Keywords: coal tar, o-Cresol, Wohl, Van Laar, three-suffix margules

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Authors: Masao Fujisawa, Hirohito Ikeda, Tomonori Ohata, Miho Yukawa, Hatsumi Aki, Takayoshi Kimura

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We attempted to predict adsorption coefficients by utilizing dispersion energies. We performed liquid-phase free energy calculations based on gas-phase geometries of organic compounds using the DFT and studied the relationship between the adsorption of organic compounds by activated carbon and dispersion energies of the organic compounds. A linear correlation between absorption coefficients and dispersion energies was observed.

Keywords: activated carbon, adsorption, prediction, dispersion energy

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Authors: Alemu Tadesse Feroche

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In this study, some 2, 3 distributed quinazoline -4 (3H) - one derivative were synthesized using a three-step synthetic route. They were obtained in a good yield (59.5-85%) by applying different chemical reactions like cyclization and condensation reactions. The chemical structure of the final compounds was also verified by spectroscopic methods (IR, ¹HNMR) and elemental microanalysis. The in vivo antimalarial activity of these compounds on P. berghei infected mice was found to be moderate to high at an oral dose of 0.04846 mmol/kg /day. This is equal to 25 mg/kg of chloroquine phosphate, which causes 100% inhibition of the parasite. It is worth mentioning that most active compounds (E) -3 Phenyl -2- [2- (pyridine -4- yl) vinyl] -4 (3H) -quinazolinone IVa (64.02%, (E)-2-[2-(4 - Hydroxy-3 - methoxystyryl) - vinyl) -3 - phenyl -4 (3H ) - quinazolinone IVc (77.25%) and (E)-2 –[2 –(Pyridin -4-yl) –vinyl] -3 phenenylamine -4(3H) quinazolinone IVe (73.54%) showed a dose-dependent increase in present suppression in antimalarial activities. Furthermore, the synthesized compounds were screened for their in vitro antileishmanial activity against L. aethiopica isolate (CL/039/09). All tested compounds (IVa (0.03766 ug/ml), IVb (0.00538 ug/ml, IVc (0.00412 ug/ml, IVd (0.00110 ug/ml), IVe (0.03017 ug/ml) and IVf (0.03894 ug/ml)) showed excellent potency that is much better than amphotericin B (IC50 = 0,04359 ug/ml). The results of acute toxicity indicated that all test compounds (IVa –IVf) proved to be nontoxic and well tolerated by the experimental animals up to 300 mg/kg in oral and 140 mg/kg in parental studies.

Keywords: 4(3H)-quinazolinone, in vivo antimalarial activity, in vitro antileishmanial activity, acute toxicity

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Authors: Marek Gancarz, Katarzyna Grądecka-Jakubowska, Urszula Malaga-Toboła, Rafał Kornas, Aleksandra Żytek, Robert Rusinek

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The aim of the research was to determine the emission of volatile organic compounds (VOCs) from corn grain depending on the degree of consolidation of the bulk material, imitating the processes occurring in silos during material storage. An electronic nose and a gas chromatograph were used for VOC analysis. Corn grain was densified under pressure of 40 and 80 kPa. Control samples of corn grain were not compacted and had bulk density. The analyzes were carried out at 14% and 17% humidity (w.b. – wet basis). The measurement system enabled quantitative and qualitative analyzes of volatile compounds and their emission intensity during the 10-day storage period. The study determined the profile of volatile compounds as a function of storage time and grain density level. The test results showed that the highest emission of volatile compounds was recorded in the first four days of storage of corn grain. VOC emissions, as well as grain moisture and volume, can be helpful in determining the quality of material stored in silos and its subsequent suitability for consumption.

Keywords: maize, consolidation, storage, VOCs, GC-MS, chemometrics

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Authors: Rita Hairani, Warinthorn Chavasiri

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Naphthoquinones are secondary metabolites widespread in nature and can be produced by plants, fungi and actinomycetes. The interest of naphthoquinones is not only limited as organic dyes, but also their wide variety of biological activities such as antitumor, antibacterial, and cytotoxic activities. Typical 1,2-naphthoquinones such as mansonones can be found in Mansonia gagei Drumm. (“chan-cha-mod”), Sterculaceae family. This plant has been used traditionally to treat some diseases such as antiemetic and antidepressant. In this study, some natural mansonones isolated from the CH2Cl2 extract of M. gagei heartwood have been assessed for their antibacterial activities using agar well diffusion method. According to the antibacterial activity results of four natural mansonones (mansonones C, E, G and H), mansonones E and G showed higher activities than the others against Staphylococcus aureus, Propionibacterium acnes and Salmonella typhi, respectively. Since mansonone G exhibited good antibacterial activity and was obtained in the highest yield, we decided to derivertize mansonone G into five ether analogues. Based on the antibacterial activities of these synthesized compounds, four ether analogues (compounds 1-4) revealed higher antibacterial activities than its natural mansonone G against S. aureus and S. typhi.

Keywords: Mansonia gagei Drumm., antibacterial activities, mansonone G, ether analogues

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Authors: A. B. Bazaralieva, A. A. Turgumbayeva

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The phytosubstance from garlic was obtained by extraction with liquid carbon dioxide under critical conditions. Methods of processing raw materials are proposed, and the chemical composition of garlic is studied by gas chromatography and mass spectrometry. The garlic extract's composition was determined using gas chromatography (GC) and gas chromatography-mass spectrophotometry (GC-MS). The phytosubstance had 54 constituents. The extract included the following main compounds: Manool (39.56%), Viridifrolol (7%), Podocarpa-1,8,11,13-tetraen-3-one, 14-isopropyl-1,13-dimethoxy- 5,15 percent, (+)-2-Bornanone (4.29%), Thujone (3.49%), Linolic acid ethyl ester (3.41%), and 12-O-Methylcarn.

Keywords: Allium sativum, bioactive compounds of garlic, carbon dioxide extraction of garlic, GS-MS method

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Authors: Marina Zulkifli, Mohd Faizal Mashhod, Noriham Abdullah

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The aim of this study was to determine the antinutrient compounds of jackfruit (Artocarpus heterophyllus) seeds as affected by thermal processes. Two types of heat treatments were applied namely boiling and microwave cooking. Results of this study showed that boiling caused a significant decrease in phytate content (30.01%), oxalate content (33.22%), saponin content (35.69%) and tannin content (44.58%) as compared to microwave cooking and raw seed. The percentage loss of antinutrient compounds in microwaved seed was: phytate 24.58%, oxalate 27.28%, saponin 16.50% and tannin 32.21%. Hence, these findings suggested that boiling is an effective treatment to reduce the level of toxic compounds in foods.

Keywords: jackfruit, heat treatments, antinutrient compounds, thermal processing

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Authors: S. Mamoucha, N. Tsafantakis, Α. Ioannidis, S. Chatzipanagiotou, C. Nikolaou, L. Skaltsounis, N. Fokialakis, N. Christodoulakis

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Introduction: Plant secondary metabolites (SM) can be grouped into three chemically distinct groups: terpenes, phenolics, and nitrogen-containing compounds. For many years the adaptive significance of SM was unknown. They were thought to be functionless end-products. Currently it is accepted that many secondary metabolites (also known as natural products) have important ecological roles in plants. For instance, they serve as attractants (odor, color, taste) for pollinators and seed-dispersing animals. Moreover, they protect plants from herbivores, microbial pathogens and from environmental stress (high and low temperatures, drought, alkalinity, salinity, radiation etc). It is well known that both biotic and abiotic stress often increase the accumulation of SM. The local climatic conditions, seasonal changes, external factors such as light, temperature, humidity affect the biosynthesis and composition of secondary metabolites. A well known dioecious evergreen plant, Pistacia lentiscus L. (mastic tree), was selected in order to study the metabolic variations occur in response to the different climate conditions, due to the seasonal variation and its effect on the biosynthesis of bioactive compounds. Materials-methods: Young and mature leaves were collected in January and July 2014, dried and extracted by accelerated solvent extraction (Dionex ASE™ 350) using solvents of increased polarity (DCM, MeOH, and H2O). GC-MS and UHPLC-HRMS analysis were carried out in order to define the nature and the relative abundance of SM. The antibacterial activity was evaluated by using the Agar Disc Diffusion Assay against ATCC and clinical isolates strains: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, Streptococcus mutans and Klebsiella pneumoniae. All tests were carried out in duplicate and the average radii of the inhibition zones were calculated for each extract. Results: According to the phytochemical profile obtained from each extract, the biosynthesis of SM varied both qualitatively and quantitatively under the two different types of seasonal stress. With exception of the biologically inactive nonpolar DCM extract of July, all extracts inhibited the growth of most of the investigated microorganisms. A clear positive correlation has been observed between the relative abundance of SM and the bioactivity of the DCM extracts of January and July. Observed changes during phytochemical analysis were mainly focused on the triterpenoid content. On the other hand, the bioactivity of the polar extracts (MeOH and H2O) of January and July resulted practically invariable against most of the microorganisms, besides the significant variation of the SM content due to the seasonal variation. Conclusion: Our results clearly confirmed the hypothesis of abiotic stress as an important regulating factor that significantly affects the biosynthesis of secondary metabolites and thus the presence of bioactive compounds. Acknowledgment: This work was supported by IKY - State Scholarship Foundation, Athens, Greece.

Keywords: antibacterial screening, phytochemical profile, Pistacia lentiscus, abiotic stress

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Authors: Ghasem Khodahami, Vahid Rowshan, Mojtaba Pakparvar

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Stachys forms one of the largest genera in the flowering plant family Lamiaceae. The number of species in the genus is estimated from about 300 to about 450 and comprises some 34 species in Iran. This genus is one of the richest sources of diterpenes which are particularly interesting because of their ecological role as antifeedants against different species of insects and for their role as the medicinal properties of the plants. The ecological distribution of Stachys inflata was studied and the resulted eco-types were sampled from four regions ranging 230-340 mm of rainfall and 1690-2125 m a.s.l of height In Fars Province Southern Iran. The essential oils of air-dried samples were obtained by hydrodistillation and analyzed by gas chromatography and gas chromatography/mass spectrometry. The number of secondary metabolites varied from 25 to 50 depending to ecological conditions. The main compounds in these areas were: Germacrene D, Bicyclogermacrene, spathulenol, δ-cadinene. Statistical analysis of photochemical resulted in recognizing 3 distinct groups that show internal variety in these herbs.

Keywords: eco-type, phytochemistry, secondary metabolites, Stachys inflata

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Authors: Ravi J. Shah

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The present study deals with the synthesis of novel spiro[azetidine-2, 3’-indole]-2’, 4(1’H)-dione derivative from the reactions of 3-(phenylimino)-1,3-dihydro-2H-indol-2-one derivatives with chloracetyl chloride in presence of triethyl amine (TEA). All the compounds were characterized using IR, 1H NMR, MS and elemental analysis. They were screened for their antibacterial and antifungal activities. Results revealed that, compounds (7a), (7b), (7c), (7d) and (7e) showed very good activity with MIC value of 6.25-12.5 μg/ml against three evaluated bacterial strains and the remaining compounds showed good to moderate activity comparable to standard drugs as antibacterial agents. Compounds (7c) and (7h) displayed equipotent antifungal activity in comparison to standard drugs. Structure-activity relationship study of the compounds showed that the presence of electron withdrawing group substitution at 5’ and 7’ positions of indoline ring and on ortho or para position of phenyl ring increases both antibacterial and antifungal activity of the compound. Henceforth, our findings will have a good impact on chemists and biochemists for further investigations in search of bromine containing spiro fused antimicrobial agents.

Keywords: antibacterial activity, antifungal activity, 2-Azetidinone, indoline

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Authors: D. S. Fardhyanti, Megawati, W. B. Sediawan

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Coal tar is a liquid by-product of the process of coal gasification and carbonation. This liquid oil mixture contains various kinds of useful compounds such as aromatic compounds and phenolic compounds. These compounds are widely used as raw material for insecticides, dyes, medicines, perfumes, coloring matters, and many others. This research investigates thermodynamic modelling of liquid-liquid equilibria (LLE) in the separation of phenol from the coal tar by solvent extraction. The equilibria are modeled by ternary components of Wohl, Van Laar, and Three-Suffix Margules models. The values of the parameters involved are obtained by curve-fitting to the experimental data. Based on the comparison between calculated and experimental data, it turns out that among the three models studied, the Three-Suffix Margules seems to be the best to predict the LLE of p-Cresol mixtures for those system.

Keywords: coal tar, phenol, Wohl, Van Laar, Three-Suffix Margules

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Authors: Marco Clericuzio, Alfredo Vizzini

Abstract:

The secondary metabolites of Russulales (one of the main orders of phylum Basidiomycota), have been studied. They are mainly terpenoids, with sesquiterpenes being the most common ones, but also triterpenoids and prenylated phenols have been isolated. We found that classes of specific compounds seem to be often allied to systematic groupings, so that they may have chemotaxonomic significance. Moreover, the ecological implications of such metabolites, as well as their biological activities, are discussed. Lately, we have focused our attention on the anti-arthropod activity of Russula metabolites, in particular on the toxicity against mites and other crop pests.

Keywords: chemotaxonomy, fungi, insecticidal activity, russulales, terpenoids

Procedia PDF Downloads 126

Authors: Bazaraliyeva Aigerim Bakytzhanovna, Turgumbayeva Aknur Amanbekovna

Abstract:

The phytosubstance from garlic was obtained by extraction with liquid carbon dioxide under critical conditions. Methods of processing raw materials are proposed, and the chemical composition of garlic is studied by gas chromatography and mass spectrometry. The garlic extract's composition was determined using gas chromatography (GC) and gas chromatography-mass spectrophotometry (GC-MS). The phytosubstance had 54 constituents. The extract included the following main compounds: Manool (39.56%), Viridifrolol (7%), Podocarpa-1,8,11,13-tetraen-3-one, 14-isopropyl-1,13-dimethoxy- 5,15 percent, (+)-2-Bornanone (4.29%), Thujone (3.49%), Linolic acid ethyl ester (3.41%), and 12-O-Methylcarn.

Keywords: allium sativum, bioactive compounds of garlic, carbon dioxide extraction of garlic, GS-MS method

Procedia PDF Downloads 54

Authors: Azizul Baten, Kamrul Hossain, Abdullah-Al-Zabir

Abstract:

The objective of this study is to develop an appropriate stochastic frontier secondary schools efficiency model by ICT Intervention and to examine the impact of ICT challenges on secondary schools efficiency in the Sylhet division in Bangladesh using stochastic frontier analysis. The Translog stochastic frontier model was found an appropriate than the Cobb-Douglas model in secondary schools efficiency by ICT Intervention. Based on the results of the Cobb-Douglas model, it is found that the coefficient of the number of teachers, the number of students, and teaching ability had a positive effect on increasing the level of efficiency. It indicated that these are related to technical efficiency. In the case of inefficiency effects for both Cobb-Douglas and Translog models, the coefficient of the ICT lab decreased secondary school inefficiency, but the online class in school was found to increase the level of inefficiency. The coefficients of teacher’s preference for ICT tools like multimedia projectors played a contributor role in decreasing the secondary school inefficiency in the Sylhet division of Bangladesh. The interaction effects of the number of teachers and the classrooms, and the number of students and the number of classrooms, the number of students and teaching ability, and the classrooms and teaching ability of the teachers were recorded with the positive values and these have a positive impact on increasing the secondary school efficiency. The overall mean efficiency of urban secondary schools was found at 84.66% for the Translog model, while it was 83.63% for the Cobb-Douglas model. The overall mean efficiency of rural secondary schools was found at 80.98% for the Translog model, while it was 81.24% for the Cobb-Douglas model. So, the urban secondary schools performed better than the rural secondary schools in the Sylhet division. It is observed from the results of the Tobit model that the teacher-student ratio had a positive influence on secondary school efficiency. The teaching experiences of those who have 1 to 5 years and 10 years above, MPO type school, conventional teaching method have had a negative and significant influence on secondary school efficiency. The estimated value of σ-square (0.0625) was different from Zero, indicating a good fit. The value of γ (0.9872) was recorded as positive and it can be interpreted as follows: 98.72 percent of random variation around in secondary school outcomes due to inefficiency.

Keywords: efficiency, secondary schools, ICT, stochastic frontier analysis

Procedia PDF Downloads 116

Authors: Cory A. Bennett

Abstract:

Teaching and learning through the use of discourse support students’ conceptual understanding by attending to key concepts and relationships. One discourse structure used in primary classrooms is number talks wherein students mentally calculate, discuss, and reason about the appropriateness and efficiency of their strategies. In the secondary mathematics classroom, the mathematics understudy does not often lend itself to mental calculations yet learning to reason, and articulate reasoning, is central to learning mathematics. This qualitative case study discusses how one secondary school in the Middle East adapted the number talk protocol for secondary mathematics classrooms. Several challenges in implementing ‘reasoning talks’ became apparent including shifting current discourse protocols and practices to a more student-centric model, accurately recording and probing student thinking, and specifically attending to reasoning rather than computations.

Keywords: discourse, reasoning, secondary mathematics, teacher development

Procedia PDF Downloads 157