Journal of Chemistry http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Preparation and Characterization of Ni-Doped Calcium Silicate Hydrate Based on Steel Slag: Adsorption Capacity for Rhodamine B from Aqueous Solution Wed, 20 May 2015 08:13:12 +0000 http://www.hindawi.com/journals/jchem/2015/131050/ Calcium silicate hydrate based on steel slag (SCSH) and Ni-doped SCSH (NSCSH) were synthesized under specific hydrothermal conditions at saturated vapor pressure and 185°C for 7 hours. The structure and morphology of SCSH and NSCSH were characterized by XRD, SEM, and N2 adsorption/desorption. SCSH mainly consisted of amorphous calcium silicate hydrate gel (C-S-H gel) together with some flake-like tobermorite and NSCSH consisted of crystalline tobermorite and xonotlite. The addition of Ni(NO3)2 had great influence on microstructure of the composites, and SCSH possesses a mesoporous structure with slit-shaped pores, but NSCSH has narrow distributions of pore size. Furthermore, NSCSH has a higher adsorption capacity for Rhodamine B (RhB) than SCSH with removal percentages of RhB of about 52.4% and 88.2%, respectively. In addition, the effects of NSCSH dosage and pH values on the adsorption of RhB were investigated. Adsorption isotherm parameters are obtained from both Langmuir and Freundlich analysis and showed a better fit to a Langmuir model. All results indicated that NSCSH has a great potential to be a safe, easily-made, and cost-effective material for the control of RhB contamination. Lu Zeng and Ligang Yang Copyright © 2015 Lu Zeng and Ligang Yang. All rights reserved. DFT Study of Polythiophene Energy Band Gap and Substitution Effects Mon, 18 May 2015 12:01:13 +0000 http://www.hindawi.com/journals/jchem/2015/296386/ Polythiophene (PTh) and its derivatives are polymer-based materials with a π-conjugation framework. PTh is a useful photoelectric material and can be used in organic semiconductor devices, such as PLED, OLED, and solar cells. Their properties are based on molecular structure; the derivatives contain different substitutes in the 3 and 5 positions, such as electron-donating or electron-withdrawing groups. All molecular geometries were optimized at B3LYP/6-31G(d,p) level of theory. The energy gap () between the HOMO and LUMO levels is related to the π-conjugation in the PTh polymer backbone. In this study, the DFT calculations were performed for the nonsubstituted and 3,5-substituted variants to investigate the stability geometries and electrical properties. The theoretical calculations show that the substituted forms are stable, have low , and are in good agreement with the experimental observations. Si. Mohamed Bouzzine, Guillermo Salgado-Morán, Mohamed Hamidi, Mohammed Bouachrine, Alison Geraldo Pacheco, and Daniel Glossman-Mitnik Copyright © 2015 Si. Mohamed Bouzzine et al. All rights reserved. Dissipation and Residue Level of Thifluzamide in Rice Field Ecosystem Sun, 17 May 2015 05:47:35 +0000 http://www.hindawi.com/journals/jchem/2015/848252/ An efficient modified QuEChERS method combined with high performance liquid chromatography-tandem mass spectrometry detection (HPLC-MS/MS) was established and evaluated for the residue analysis of thifluzamide in rice grain, husk, straw, seedling, paddy water, and soil. Thifluzamide residues were extracted with acetonitrile, cleaned up with primary secondary amine (PSA), and then determined by HPLC-MS/MS. The fortified recoveries were 76%–106% with RSDs of 3%–13%. The results of the supervised field trials at two experiment sites showed that thifluzamide dissipated rapidly in paddy fields, and the half-lives in paddy water, soil, and rice seedling were 0.3–0.6 d, 1.8–3.6 d, and 4.3–13.9 d, respectively. At harvest time, when the preharvest interval (PHI) was set as 21 d, the final residues of thifluzamide in rice grains were below the maximum residue limit (MRL) of 0.5 mg/kg set by Japan, whereas the final residues in rice husk and straw were still high (the highest value reached 1.36 mg/kg in rice husk and 0.83 mg/kg in rice straw). The results indicated that the highest residue in rice grain was 0.23 mg/kg when PHI was 21 d, and only 6.9–11.0% of acute risk quotient of thifluzamide was occupied by the dietary daily intake in Chinese population consuming rice. Weitao Chen, Minghui Li, Wenxi Li, Xuemin Wu, and Lijun Han Copyright © 2015 Weitao Chen et al. All rights reserved. Synthesis and Antibacterial Activity of New Spiro[thiadiazoline-(pyrazolo[3,4-d]pyrimidine)] Derivatives Wed, 13 May 2015 07:10:39 +0000 http://www.hindawi.com/journals/jchem/2015/982404/ New heterocyclic compounds spiroderivatives of allopurinol of biological interest were prepared from allopurinol via thionation and 1,3-dipolar cycloaddition and were produced in high to excellent yields. These compounds were characterized on the basis of spectral and spectroscopic data (1H NMR, 13C, IR, and MS). The antibacterial activity of the synthesized products was studied using bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Compounds having an ethyl group showed the best activity with MIC value of 31.25 µg/mL against Staphylococcus aureus and Streptococcus fasciens. Mohammed El Fal, Youssef Ramli, Abdelfettah Zerzouf, Ahmed Talbaoui, Youssef Bakri, and El Mokhtar Essassi Copyright © 2015 Mohammed El Fal et al. All rights reserved. Near Surface Stoichiometry in UO2: A Density Functional Theory Study Tue, 12 May 2015 09:47:34 +0000 http://www.hindawi.com/journals/jchem/2015/142510/ The mechanisms of oxygen stoichiometry variation in UO2 at different temperature and oxygen partial pressure are important for understanding the dynamics of microstructure in these crystals. However, very limited experimental studies have been performed to understand the atomic structure of UO2 near surface and defect effects of near surface on stoichiometry in which the system can exchange atoms with the external reservoir. In this study, the near (110) surface relaxation and stoichiometry in UO2 have been studied with density functional theory (DFT) calculations. On the basis of the point-defect model (PDM), a general expression for the near surface stoichiometric variation is derived by using DFT total-energy calculations and atomistic thermodynamics, in an attempt to pin down the mechanisms of oxygen exchange between the gas environment and defected UO2. By using the derived expression, it is observed that, under poor oxygen conditions, the stoichiometry of near surface is switched from hyperstoichiometric at 300 K with a depth around 3 nm to near-stoichiometric at 1000 K and hypostoichiometric at 2000 K. Furthermore, at very poor oxygen concentrations and high temperatures, our results also suggest that the bulk of the UO2 prefers to be hypostoichiometric, although the surface is near-stoichiometric. Jianguo Yu, Billy Valderrama, Hunter B. Henderson, Michele V. Manuel, and Todd Allen Copyright © 2015 Jianguo Yu et al. All rights reserved. Solid-Phase Extraction of Pesticides by Using Bioinspired Peptide Receptors Tue, 12 May 2015 09:24:46 +0000 http://www.hindawi.com/journals/jchem/2015/905701/ A virtual development of hexapeptide receptors bioinspired by the acetylcholinesterase enzyme active site is proposed. A semicombinatorial approach was applied to generate a virtual hexapeptides library with different affinity properties towards organophosphate and carbamate pesticides. The virtual screening process was addressed to obtain peptides able to separate pesticide subclasses in the experimental work. Three hexapeptides, two generated by molecular modeling and one having a scrambled sequence, were used as selective sorbent materials for pesticides in preanalytical solid-phase extraction (SPE) method. Selective adsorption and cross-reactivity were tested directly on a mix of four pesticides (carbaryl, chlorpyrifos-ethyl, malathion, and thiabendazole) having different structures and physico-chemical properties, at a total concentration of 120 ppb (each pesticide at concentration of 30 ppb). The results were compared to traditional sorbent material such as C-18 and strata-X. Data showed that only one of the hexapeptides virtually designed had significant differences in competitive absorption between aliphatic pesticide malathion, fungicide thiabendazole chosen as negative control, and aromatic pesticides. These results partially supported the simulated strategy. Valentina Lanzone, Manuel Sergi, Marcello Mascini, Rossana Scarpone, Flavio Della Pelle, Michele Del Carlo, Giampiero Scortichini, and Dario Compagnone Copyright © 2015 Valentina Lanzone et al. All rights reserved. Storage Effect on Phenols and on the Antioxidant Activity of Extracts from Anemopsis californica and Inhibition of Elastase Enzyme Tue, 12 May 2015 09:22:57 +0000 http://www.hindawi.com/journals/jchem/2015/602136/ The amount of total phenols and flavonoids and the antioxidant activity of leaf, stem, and rhizome methanolic extracts from a commonly consumed Anemopsis californica under different storage conditions were investigated. Storage conditions were at 50, 25, 4, and −20°C, protected or not from light, during 180 days. The inhibition of the elastase enzyme was also evaluated. The results demonstrated that leaf, stem, and rhizome methanolic extracts of Anemopsis californica maintain approximately up to 97 and 95% stability in phenolic content and antioxidant activity, respectively, when stored during 60 days at −20°C in the dark. Additionally, these extracts, principally from leaf and rhizome, showed an elastase inhibitory effect by 75 and 71.8%, respectively. Therefore, this study provides the basis for further research on the anti-inflammatory activity. On the other hand, Anemopsis californica could comprise a good alternative of use as antioxidant in foods. Carmen Lizette Del-Toro-Sánchez, Melesio Gutiérrez-Lomelí, Eugenia Lugo-Cervantes, Florentina Zurita, Miguel Angel Robles-García, Saul Ruiz-Cruz, Jose Antonio Aguilar, Juan Alfredo Morales-Del Rio, and Pedro Javier Guerrero-Medina Copyright © 2015 Carmen Lizette Del-Toro-Sánchez et al. All rights reserved. Identification of Repellent and Insecticidal Constituents from Artemisia mongolica Essential Oil against Lasioderma serricorne Mon, 11 May 2015 14:24:26 +0000 http://www.hindawi.com/journals/jchem/2015/549057/ The aims of this research were to determine the chemical composition and insecticidal and repellent activities of the Artemisia mongolica essential oil against Lasioderma serricorne and to isolate active constituents from the essential oil. The essential oil of A. mongolica was obtained by hydrodistillation and 36 components were identified with GC-MS. Eucalyptol (39.88%), (S)-cis-verbenol (14.93%), 4-terpineol (7.20%), (−)-camphor (6.02%), and α-terpineol (4.20%) were found to be major components. With a further isolation process, five constituents obtained from the essential oil were identified as eucalyptol, verbenol, 4-terpineol, camphor, and α-terpineol. In the progress of assay, it showed that L. serricorne adults had different sensitivities to the crude essential oil and isolated constituents. 4-Terpineol exhibited strongest contact activity against L. serricorne, showing the LD50 value of 8.62 μg/adult. Moreover, camphor and α-terpineol showed stronger fumigant activity ( and 3.27 mg/L air, resp.) against L. serricorne than crude essential oil and other constituents. In addition, the essential oil, eucalyptol, verbenol, and α-terpineol showed comparable repellency against L. serricorne adults. The results indicate that the essential oil and isolated compounds have potential to provide more efficient and safer natural insecticides or repellents for control of insects in food and Chinese medicinal materials preservation. Chunxue You, Shanshan Guo, Wenjuan Zhang, Kai Yang, Zhufeng Geng, Shushan Du, Chengfang Wang, and Zhiwei Deng Copyright © 2015 Chunxue You et al. All rights reserved. Chemical Reactivity of Isoproturon, Diuron, Linuron, and Chlorotoluron Herbicides in Aqueous Phase: A Theoretical Quantum Study Employing Global and Local Reactivity Descriptors Mon, 11 May 2015 11:08:43 +0000 http://www.hindawi.com/journals/jchem/2015/751527/ We have calculated global and local DFT reactivity descriptors for isoproturon, diuron, linuron, and chlorotoluron herbicides at the MP2/6-311++G(2d,2p) level of theory. The results suggest that, in aqueous conditions, chlorotoluron, linuron, and diuron herbicides may be degraded by elimination of urea moiety through electrophilic attacks. On the other hand, electrophilic, nucleophilic, and free radical attacks on isoproturon may cause the elimination of isopropyl fragment. Luis Humberto Mendoza-Huizar Copyright © 2015 Luis Humberto Mendoza-Huizar. All rights reserved. Characteristics of a New Plastic Explosive Named EPX-1 Sun, 10 May 2015 09:16:23 +0000 http://www.hindawi.com/journals/jchem/2015/861756/ EPX-1 is a new plastic explosive (in the research stage) which has been prepared for military and civilian applications. EPX-1 explosive contains pentaerythritol tetranitrate (PETN) with different particle size as explosive filler bonded by nonenergetic thermoplastic binder plasticized by dibutyl phthalate (DBP). In this paper, the production method of EPX-1 was described. The crystal morphology was studied by scanning electron microscope (SEM). Heat of combustion was determined experimentally. The compatibility of PETN with the polymeric matrix was studied by vacuum stability test. Sensitivities to impact and friction were measured. The detonation velocity was measured experimentally and the detonation characteristics were calculated by EXPLO5 thermodynamic code. For comparison, Semtex 1A, Semtex 10, Formex P1, and Sprängdeg m/46 were studied. It was concluded that PEX-1 has compatible ingredients, it has the highest detonation velocity of all the studied plastic explosives, and its sensitivity is in the same level of the studied plastic explosives except Semtex 1A. Ahmed Elbeih Copyright © 2015 Ahmed Elbeih. All rights reserved. Synthesis and Characterization of PPV Monomer for Subsequent Electropolymerization Sun, 10 May 2015 08:41:24 +0000 http://www.hindawi.com/journals/jchem/2015/620938/ Organic synthesis of the monomer of poly(p-phenylenevinylene) was performed starting by the 2,5-dimethylphenol compound. An iodine atom was added to one end of the aromatic ring and then the iodine atom was substituted by a cyano group. Opposite to the cyano group was added a chain of six carbon atoms and the end of the carbon chain has an added bromine atom. The characterizations of the obtained compounds were made by FTIR, GC-MS, 1H, and 13C NMR and showed that almost all of the proposed monomers were obtained in their totality. Álvaro Fontana, Fábio Santana dos Santos, Flávia Aparecida Fonseca, Adonilson Dos Reis Freitas, Andersson Barison, and Jarem Raul Garcia Copyright © 2015 Álvaro Fontana et al. All rights reserved. In Vitro Enzyme Inhibition Potentials and Antioxidant Activity of Synthetic Flavone Derivatives Sun, 10 May 2015 07:55:10 +0000 http://www.hindawi.com/journals/jchem/2015/516878/ Free radicals are produced by an important chemical process known as oxidation that in turn initiates chain reactions to damage the cells and originate oxidative stress. Flavones have got special position in research field of natural and synthetic organic chemistry due to their biological capabilities as antioxidant. The antioxidants are known to possess extensive biological effects that include antiviral, antibacterial, anti-inflammatory, antithrombotic, and vasodilatory activities. The simple flavone (F1) and substituted flavone derivatives (F2–F5) have been synthesized from o-hydroxyacetophenone and benzaldehyde derivatives in good yield. The structures have been established by different spectroscopic techniques like 1H NMR, 13C NMR, IR, and elemental analysis. Antioxidant profile of these compounds was established using DPPH and H2O2 free radical scavenging assay. The findings showed that halogenated flavones showed more enzyme inhibitions and antioxidant activities than simple flavones and are potential candidates for the treatment of wide range of diseases. Mohammad Shoaib, Syed Wadood Ali Shah, Niaz Ali, Ismail Shah, Muhammad Naveed Umar, Shafiullah, Muhammad Ayaz, Muhammad Nawaz Tahir, and Sohail Akhtar Copyright © 2015 Mohammad Shoaib et al. All rights reserved. The Leachate Release and Microstructure of the Sewage Sludge under the Anaerobic Fermentation Thu, 07 May 2015 16:53:36 +0000 http://www.hindawi.com/journals/jchem/2015/901021/ Pollutant release, pore structure, and thermal effect of sewage sludge during anaerobic fermentation were investigated. Results showed that the pH value firstly declined and then increased during anaerobic fermentation. The BOD5 and organics of sewage sludge declined, and the BOD5 of samples which was originally neutral declined as much as 53.6%. The micropore of samples was relatively developed. The biggest adsorption amount was 69.2 cm3/g. The average pore size was enlarged about 16.0–19.8% under anaerobic fermentation. There existed endothermic valley during heating procedure of 0–200∘C because of the dehydration, and the mass loss was 60.9–72.5%. The endothermic valley of the sample fluctuated at the 14th day in the anaerobic fermentation. During the heating procedure of 200–600∘C, there existed exothermal peaks because of the oxidation and burning of the organics. The curve of sample which was originally neutral had comparatively large endothermic valley and exothermal peak. Yiqie Dong, Haijun Lu, Jixiang Li, and Changhong Wang Copyright © 2015 Yiqie Dong et al. All rights reserved. The Coupled Effect of Temperature and Carbonation on the Corrosion of Rebars in the Simulated Concrete Pore Solutions Wed, 06 May 2015 11:07:31 +0000 http://www.hindawi.com/journals/jchem/2015/462605/ The reinforced concrete structures have to survive high temperature and carbonation at low latitude region. The research on the effect of temperature and the effect of carbonation are vital to the corrosion of the rebars in concrete structures. The coupled effect of temperature and carbonation on the corrosion of rebars was researched by using the open circuit potential (OCP), the electrochemical impedance spectroscopy (EIS), and the potentiodynamic polarization (PP) measurement in the simulated concrete pore solutions (SPSs). The high temperature environment is conducive to the formation of passivated surface of rebars in SPSs, but the dissolution velocity of passivated surface is higher. The rebars have the greater capacity of passivity at lower temperature. The corrosion rate of rebars at higher temperature is smaller in moderate pH value (10.6) SPSs. The rebars suffer from serious corrosion in the pH = 9.6 SPSs at 318 K temperature. Jiezhen Hu, Xuequn Cheng, Xiaogang Li, Peichang Deng, and Gui Wang Copyright © 2015 Jiezhen Hu et al. All rights reserved. Extraction Techniques for Bioactive Compounds and Antioxidant Capacity Determination of Chilean Papaya (Vasconcellea pubescens) Fruit Tue, 05 May 2015 13:14:23 +0000 http://www.hindawi.com/journals/jchem/2015/347532/ The aim of this work was to assess and compare different extraction methods by using high hydrostatic pressure (HHPE), ultrasound (UE), agitation (AE), and their combinations for the extraction of bioactive compounds of Chilean papaya. Extract antioxidant capacity was evaluated by three methods (i.e., DPPH, FRAP, and Voltammetry) and phenolic compounds and vitamin C were determined by HPLC. Papaya sample extraction was performed by HHPE at 500 MPa for 10 min and UE and AE for 30 min, respectively. The combined-extractions: HHPE-UE and HHPE-AE, were carried out for 5 min and 15 min, respectively. The highest values found were total phenolic 129.1 mg GAE/100 g FW, antioxidant capacity by DPPH 20.6 mM TE/100 g FW, and voltammetry 141.0 mM TE/100 g FW for HHPE-UE method in free compound extraction. Regarding vitamin C content, its highest value was found by HHPE-UE (74 mg/100 g FW) a combined extraction method. The phenolic compounds rutin and p-coumaric acid were found in all the extracts, both in free and bound forms, respectively. Besides, the combined techniques improved the extraction of bioactive compounds. Elsa Uribe, Alvaro Delgadillo, Claudia Giovagnoli-Vicuña, Issis Quispe-Fuentes, and Liliana Zura-Bravo Copyright © 2015 Elsa Uribe et al. All rights reserved. Synthesis of PAMAM Dendrimers Loaded with Mycophenolic Acid to Be Studied as New Potential Immunosuppressants Tue, 05 May 2015 12:35:07 +0000 http://www.hindawi.com/journals/jchem/2015/263072/ The terminal N-Boc protected diamino PAMAM 7 was condensed (EDC-DMAP) with two units of mycophenolic acid (MPA) giving the N-Boc protected dendron 8 in a good yield (76%). The ammonium trifluoroacetate 9 was prepared from 8 by acid treatment (TFA-THF-H2O) and was split into two equal parts. The first half was treated with di-2-pyridyl thionocarbonate (DPT) in the presence of Et3N to give the corresponding isothiocyanate 10. This was reacted with the second half of 9 providing the symmetrical dendrimer 11 (68% yield), exposing four MPA units around the thioureido-PAMAM core. Lorenzo Guazzelli, Felicia D’Andrea, Francesco Giorgelli, Giorgio Catelani, Alessandra Panattoni, and Andrea Luvisi Copyright © 2015 Lorenzo Guazzelli et al. All rights reserved. Towards the Application of Atorvastatin to Intensify Proapoptotic Potential of Conventional Antileukemic Agents In Vitro Mon, 04 May 2015 13:20:52 +0000 http://www.hindawi.com/journals/jchem/2015/162956/ It has been previously revealed that statins used at high concentrations display antileukemic potential towards chronic lymphocytic leukemia (CLL) cells. However, their usage alone in clinical practice may be limited due to possible side effects of high doses of these drugs. On the other hand, combined treatment of leukemia with statins and the conventional chemotherapeutics is questionable because of unknown influence of the first on the standard treatment results. This study has revealed that in vitro atorvastatin increases the proapoptotic potential of cladribine and mafosfamide in CLL cells isolated from peripheral blood of patients. Moreover, a preincubation with the above statin sensitizes leukemic cells to CM-induced apoptosis even at small concentrations of the drug. The usage of atorvastatin together with or followed by the conventional chemotherapy should be considered as therapeutic option for the treatment for this leukemia. Interestingly, CM-resistant patients might have the biggest benefits from atorvastatin administration. Jolanta D. Żołnierczyk, Arleta Kaźmierczuk, Paweł Hikisz, Barbara Cebula-Obrzut, Ewa Wawrzyniak, Jerzy Z. Błoński, Małgorzata Misiewicz, Paweł Robak, Piotr Smolewski, and Zofia M. Kiliańska Copyright © 2015 Jolanta D. Żołnierczyk et al. All rights reserved. A New Experimental Method to Determine the Henry’s Law Constant of a Volatile Organic Compound Adsorbed in Soil Mon, 04 May 2015 08:43:13 +0000 http://www.hindawi.com/journals/jchem/2015/479327/ This paper presents a new mechanical method to determine Henry’s law constant (HLC) of a volatile organic compound (VOC). This method is an extension of the one proposed by Ouoba et al. (2010) to determine the water activity in porous media. This work focuses on TCE and aims at characterizing its liquid-vapor equilibrium in various cases in the form of a pure liquid phase or dissolved in an aqueous solution, adsorbed or not in a natural soil. A liquid phase is disposed in a closed chamber whose volume can be incrementally increased. The recording of the total gas pressure leads to evaluating the vapor partial pressure of a volatile compound even in the case of an aqueous solution. This method has been validated using various aqueous solutions of TCE and the HLC obtained is in agreement with the literature. Then, the validity of Henry’s law has been asserted in the case of an aqueous solution of TCE adsorbed in a hygroscopic soil. Indeed, a linear relation between the vapor partial pressure of TCE and its concentration has been obtained while the HLC is about 16% lower. This result highlights the influence of adsorption phenomena on vapor/liquid equilibrium. S. Ouoba, F. Cherblanc, J. Koulidiati, and J.-C. Bénet Copyright © 2015 S. Ouoba et al. All rights reserved. Comparison of Fatty Acid Composition between Female and Male Japanese Quail Meats Sun, 03 May 2015 16:18:58 +0000 http://www.hindawi.com/journals/jchem/2015/569746/ The objective of the present study was to compare the proximate analysis, fatty acids composition, omega fatty acids, trans fatty acids (TFAs), and ratio of the total poly unsaturated fatty acid (PUFA) and total saturated fatty acid (SFA) of female and male quail meats. Significant differences were not observed between pH, crude fat, moisture, and ash content of female and male quail meats (). The male quail meat had higher fat and ash contents and lower moisture content than those of the female quail meat. The pHs of male and female quail meat were found to be 6.22 and 6.21, respectively. The results of the fatty acid composition analysis showed that C18:1 (42.14–41.23%), C16:0 (24.31–25.76%), C18:2 (13.82–13.42%), and C18:0 (7.49–7.32%) were found as the major fatty acids in the female and male quail meats. Total TFAs, SFA, monounsaturated fatty acids (MUFA), and PUFA content of the female and male quail meats were found to be 2.79–2.82%, 33.22–34.65%, 49.70–48.72%, and 14.29–13.81%, respectively. Umit Gecgel, Ismail Yilmaz, Eser Kemal Gurcan, Salih Karasu, and Gizem Cagla Dulger Copyright © 2015 Umit Gecgel et al. All rights reserved. A New Equation Relating the Viscosity Arrhenius Temperature and the Activation Energy for Some Newtonian Classical Solvents Sun, 03 May 2015 14:21:03 +0000 http://www.hindawi.com/journals/jchem/2015/163262/ In transport phenomena, precise knowledge or estimation of fluids properties is necessary, for mass flow and heat transfer computations. Viscosity is one of the important properties which are affected by pressure and temperature. In the present work, based on statistical techniques for nonlinear regression analysis and correlation tests, we propose a novel equation modeling the relationship between the two parameters of viscosity Arrhenius-type equation, such as the energy () and the preexponential factor (). Then, we introduce a third parameter, the Arrhenius temperature (), to enrich the model and the discussion. Empirical validations using 75 data sets of viscosity of pure solvents studied at different temperature ranges are provided from previous works in the literature and give excellent statistical correlations, thus allowing us to rewrite the Arrhenius equation using a single parameter instead of two. In addition, the suggested model is very beneficial for engineering data since it would permit estimating the missing parameter value, if a well-established estimate of the other parameter is readily available. Aymen Messaâdi, Nesrine Dhouibi, Hatem Hamda, Fethi Bin Muhammad Belgacem, Yousry Hessein Adbelkader, Noureddine Ouerfelli, and Ahmed Hichem Hamzaoui Copyright © 2015 Aymen Messaâdi et al. All rights reserved. Physicochemical Quality Parameters at the Reception of the Honey Packaging Process: Influence of Type of Honey, Year of Harvest, and Beekeeper Sun, 03 May 2015 12:46:22 +0000 http://www.hindawi.com/journals/jchem/2015/929658/ The aim of this paper was to evaluate the influence of the type of honey, year of collection, and the beekeeper on the main physicochemical quality parameters (hydroxymethylfurfural “HMF,” moisture, and colour), measured on reception of the raw honey. 1593 samples (11 types of honey categorized by means of pollinic analysis), provided by 98 beekeepers, from 2009 to 2013, were analyzed. Colour was the parameter most affected by the type of honey and year, whereas HMF was the least affected in both cases. The clearest honeys were found to have the greatest moisture (orange, rosemary, and lemon) and the darkest had the least moisture (lavender stoechas, eucalyptus, sunflower, honeydew and retama). Lavender, polyfloral, and thyme had intermediate values of these parameters. For moisture, most samples were in accordance with international requirements (less than 20 g/100 g). All values were below the required limit for HMF (40 mg/kg), although a few of them were abnormally high as they were raw honeys (i.e., 2% of the samples had values higher than 20 mg/kg). The fact that all the inadequate samples came from specific beekeepers highlights the importance of their role, suggesting that training in good practices is the key to guarantee honey quality before it reaches the industry. Marisol Juan-Borrás, Eva Domenech, Andrea Conchado, and Isabel Escriche Copyright © 2015 Marisol Juan-Borrás et al. All rights reserved. Photocatalytic Activity in Phenol Removal of Water from Graphite and Graphene Oxides: Effect of Degassing and Chemical Oxidation in the Synthesis Process Thu, 30 Apr 2015 09:44:58 +0000 http://www.hindawi.com/journals/jchem/2015/254631/ Developing new materials or modifying the existing ones is an amply field studied in the world of research. Due to its outstanding physical and chemical properties, graphene is attractive material for new applications. The methodologies for obtaining graphene are diverse and have changed over time. Graphene oxide is a versatile form of graphene, due to the presence of oxygenated functional groups. Chemical oxidation of graphite and exfoliation by ultrasonic waves is one of the preferred methods to obtain graphene oxide; chemical oxidation time and the degassing effect in the ultrasonic bath are parameters that play an important role in the features and properties of graphene oxide. Thus, in this study, the conventional times used for the oxidation of graphite and degassing in an ultrasonic bath to obtain graphene oxide were modified. The structural changes in the carbon materials were evaluated based on their photocatalytic activity in the removal of an organic pollutant in water (removing up to 38% of phenol). The band gaps of the graphitic materials were obtained by UV-vis obtaining a value range of 1.5–4.7 eV and the structure and morphology of the carbon materials were characterized by infrared and Raman spectroscopies and transmission electron microscopy, respectively. Karina Bustos-Ramirez, Carlos Eduardo Barrera-Diaz, Miguel De Icaza, Ana Laura Martínez-Hernández, and Carlos Velasco-Santos Copyright © 2015 Karina Bustos-Ramirez et al. All rights reserved. Characterization, Dissolution, and Solubility of Lead Hydroxypyromorphite [Pb5(PO4)3OH] at 25–45°C Thu, 30 Apr 2015 07:32:23 +0000 http://www.hindawi.com/journals/jchem/2015/269387/ Dissolution of the hydroxypyromorphite [lead hydroxyapatite, Pb5(PO4)3OH] in HNO3 solution (pH = 2.00), ultrapure water (pH = 5.60), and NaOH solution (pH = 9.00) was experimentally studied at 25°C, 35°C, and 45°C. The XRD, FT-IR, and FE-SEM analyses indicated that the hydroxypyromorphite solids were observed to have indistinguishable change during dissolution. For the hydroxypyromorphite dissolution in aqueous acidic media at initial pH 2.00 and 25°C, the aqueous phosphate concentrations rose quickly and reached the peak values after 1 h dissolution, while the aqueous lead concentrations rose slowly and reached the peak values after 1440 h. The solution Pb/P molar ratio increased constantly from 1.10 to 1.65 near the stoichiometric ratio of 1.67 to 209.85~597.72 and then decreased to 74.76~237.26 for the dissolution at initial pH 2.00 and 25°C~45°C. The average values for Pb5(PO4)3OH were determined to be 10−80.77 (10−80.57−10−80.96) at 25°C, 10−80.65 (10−80.38−10−80.99) at 35°C, and 10−79.96 (10−79.38−10−80.71) at 45°C. From the obtained solubility data for the dissolution at initial pH 2.00 and 25°C, the Gibbs free energy of formation [] for Pb5(PO4)3OH was calculated to be −3796.71 kJ/mol (−3795.55~−3797.78 kJ/mol). Yinian Zhu, Zongqiang Zhu, Xin Zhao, Yanpeng Liang, and Yanhua Huang Copyright © 2015 Yinian Zhu et al. All rights reserved. A Molecular Dynamic Simulation of Hydrated Proton Transfer in Perfluorosulfonate Ionomer Membranes (Nafion 117) Thu, 30 Apr 2015 06:16:28 +0000 http://www.hindawi.com/journals/jchem/2015/169680/ A molecular dynamic model based on Lennard-Jones Potential, the interaction force between two particles, molecular diffusion, and radial distribution function (RDF) is presented. The diffusion of the hydrated ion, triggered by both Grotthuss and vehicle mechanisms, is used to study the proton transfer in Nafion 117. The hydrated ion transfer mechanisms and the effects of the temperature, the water content in the membrane, and the electric field on the diffusion of the hydrated ion are analyzed. The molecular dynamic simulation results are in good agreement with those reported in the literature. The modeling results show that when the water content in Nafion 117 is low, H3O+ is the main transfer ion among the different hydrated ions. However, at higher water content, the hydrated ion in the form of H+(H2O)2 is the main transfer ion. It is also found that the negatively charged sulfonic acid group as the fortified point facilitates the proton transfer in Nafion 117 better than the free water molecule. The diffusion of the hydrated ion can be improved by increasing the cell temperature, the water content in Nafion, and the electric field intensity. Hong Sun, Mingfu Yu, Zhijie Li, and Saif Almheiri Copyright © 2015 Hong Sun et al. All rights reserved. Chemical and Microbiological Characterization for PDO Labelling of Typical East Piedmont (Italy) Salami Wed, 29 Apr 2015 15:07:56 +0000 http://www.hindawi.com/journals/jchem/2015/597471/ This study is focused on the characterisation of typical salami produced in Alessandria province (North West of Italy). Seventeen small or medium salami producers from this area were involved in the study and provided the samples investigated. The aim is double and consists in obtaining a screening of the characteristics of different products and following their evolution along ripening. The study involved five types of typical salami that were characterised for aroma components and nutritional features. This approach could provide a basis for a possible PDO or PGI label request. Principal Component Analysis and cluster analysis were used as multivariate statistical tools for data treatment. The overall results obtained point out that the products investigated do not deviate from analogous European products and show the possibility of characterising by specific parameters three main groups of samples: Salamini di Mandrogne, Muletta, and Nobile Giarolo; moreover some considerations can also be drawn with respect to the nutritional characterization considering the biogenic amines profile. V. Gianotti, S. Panseri, E. Robotti, M. Benzi, E. Mazzucco, F. Gosetti, P. Frascarolo, M. Oddone, M. Baldizzone, E. Marengo, and L. M. Chiesa Copyright © 2015 V. Gianotti et al. All rights reserved. The Feasibility of Using Tartary Buckwheat as a Se-Containing Food Material Wed, 29 Apr 2015 14:10:16 +0000 http://www.hindawi.com/journals/jchem/2015/246042/ Tartary buckwheat (Fagopyrum tataricum) is a semiwild plant grown in the Himalaya region. Due to its high concentration of flavonoids and trace elements it is of interest for cultivation in other countries as well. The feasibility of increasing the concentration of Se in grain and in green parts of Tartary buckwheat has not yet been investigated. The aim of this investigation was thus to determine the concentration of Se in different edible parts of Tartary buckwheat treated with different concentrations of Na selenate using different techniques. In plants grown in soil fertilized once with 0.5 and 10 mg Se L−1, Se was efficiently translocated from the roots to the leaves and seeds. Foliar spraying with 0.5 mg Se L−1 increased Se content in leaves and seeds. Among the edible parts of Tartary buckwheat plants the highest content of Se in control and in treated groups was found in leaves, followed by seeds and stems. Regarding recommended Se concentration, edible parts of Tartary buckwheat were safe for human consumption. Soil fertilization with 0.5 and 10 mg Se L−1 and foliar fertilization with 0.5 mg Se L−1 are applicable for cultivation of Tartary buckwheat as a functional food enriched with Se. Aleksandra Golob, Vekoslava Stibilj, Ivan Kreft, and Mateja Germ Copyright © 2015 Aleksandra Golob et al. All rights reserved. Coccoloba uvifera (L.) (Polygonaceae) Fruit: Phytochemical Screening and Potential Antioxidant Activity Wed, 29 Apr 2015 14:09:49 +0000 http://www.hindawi.com/journals/jchem/2015/534954/ The flora of Latin America attracts gaining interest as it provides a plethora of still unexplored or underutilized fruits that can contribute to human well-being due to their nutritional value and their content of bioactive compounds. Antioxidant compounds are now of considerable interest due to their effect of preventing or delaying aging and their apparent involvement in prevention of numerous human diseases, including cancer, atherosclerosis, Alzheimer’s disease, inflammation, and rheumatoid arthritis. In this work, the fruit of Coccoloba uvifera (L.) was investigated for their in vitro antioxidant capacity using two assays based on reactions with a relatively stable single reagent radical (Trolox equivalent antioxidant capacity, TEAC; and DPPH free radical scavenging assay, DPPH), two assays based on chelating of metallic cations, and one based on the reduction of oxidized species. The TEAC value on ABTS radical, DPPH scavenging activity, ion chelation, and reducing power were found to be 897.6 μM of Trolox/100 g of sample, 22.8% of DPPH free radical scavenging, 11.3% of Cu2+-chelating activity, 23.9% of Fe2+-chelating activity, and a Fe2+-reducing power of 0.76 mg/mL, respectively. The free radical scavenging and antioxidant characteristics of C. uvifera may be due to the presence of diverse phytochemicals in the fruit as anthocyanins, ascorbic acid, phenolic compounds, and flavonoids. Maira Rubi Segura Campos, Jorge Ruiz Ruiz, Luis Chel-Guerrero, and David Betancur Ancona Copyright © 2015 Maira Rubi Segura Campos et al. All rights reserved. A Comprehensive Review on Measurement and Correlation Development of Capillary Pressure for Two-Phase Modeling of Proton Exchange Membrane Fuel Cells Wed, 29 Apr 2015 12:05:24 +0000 http://www.hindawi.com/journals/jchem/2015/876821/ Water transport and the corresponding water management strategy in proton exchange membrane (PEM) fuel cells are quite critical for the improvement of the cell performance. Accuracy modeling of water transport in porous electrodes strongly depends on the appropriate constitutive relationship for capillary pressure which is referred to as - correlation, where is the capillary pressure and is the fraction of saturation in the pores. In the present PEM fuel cell two-phase models, the Leverett-Udell - correlation is widely utilized which is proposed based on fitting the experimental data for packed sands. However, the size and structure of pores for the commercial porous electrodes used in PEM fuel cells differ from those for the packed sands significantly. As a result, the Leverett-Udell correlation should be improper to characterize the two-phase transport in the porous electrodes. In the recent decade, many efforts were devoted to measuring the capillary pressure data and developing new - correlations. The objective of this review is to review the most significant developments in recent years concerning the capillary pressure measurements and the developed - correlations. It is expected that this review will be beneficial to develop the improved PEM fuel cell two-phase model. Chao Si, Xiao-Dong Wang, Wei-Mon Yan, and Tian-Hu Wang Copyright © 2015 Chao Si et al. All rights reserved. Nutritional Content and Elemental and Phytochemical Analyses of Moringa oleifera Grown in Mexico Tue, 28 Apr 2015 13:20:24 +0000 http://www.hindawi.com/journals/jchem/2015/860381/ Moringa oleifera is a tree distributed in Mexican semiarid and coastal regions. M. oleifera is used in practice in the treatment of various diseases and is available without a medical prescription, often in the form of an herbal infusion for everyday use. The aim of the present study was to evaluate the chemical composition and nutritional values of dried M. oleifera leaf powder collected from two different regions in Mexico. All samples of M. oleifera exhibited moisture levels varying from 3.06 to 3.34%, lipids from 10.21 to 10.31%, fiber from 7.29 to 9.46%, ashes from 10.71 to 11.18%, crude protein from 10.74 to 11.48%, and carbohydrates from 54.61 to 57.61%. The predominant mineral elements in the leaf powder according to ICP-MS were Ca (2016.5–2620.5 mg/100 g), K (1817–1845 mg/100 g), and Mg (322.5–340.6 mg/100 g). The HPLC analysis indicated the presence of phenolic acids (gallic and chlorogenic acids) and flavonoids (rutin, luteolin, quercetin, apigenin, and kaempferol). We concluded that Lombardia M. oleifera samples could be employed in edible and commercial applications. Our results showed that the highest mean value of As from the San Pedro samples exceeds the recommended level and may constitute a health hazard to consumers. Mónica A. Valdez-Solana, Verónica Y. Mejía-García, Alfredo Téllez-Valencia, Guadalupe García-Arenas, José Salas-Pacheco, José J. Alba-Romero, and Erick Sierra-Campos Copyright © 2015 Mónica A. Valdez-Solana et al. All rights reserved. Hydrolysis and Hydrazinolysis of Isatin-Based Ald- and Ketazines Tue, 28 Apr 2015 13:01:17 +0000 http://www.hindawi.com/journals/jchem/2015/826489/ The hydrolysis of isatin aldazine 4a–d afforded the unexpected 3,3′-(hydrazine-1,2-diylidene)bis(indolin-2-one) (5) and 1,2-di(arylidene)hydrazines 6a–d through dual hydrolysis of 4a–d. A mechanism to explain the formation of 5 and 6a–d was proposed. In addition, the hydrazinolysis of 4a–d yielded 3-hydrazonoindolin-2-one (2) and 1,2-di(arylidene)hydrazines 6a–d instead of hydrazones 17a–d, while hydrazinolysis of isatin ketazine 5 gave the expected 3-hydrazonoindolin-2-one (2). These results indicated the ability of the title compounds for unusual hydrolysis and hydrazinolysis reactions. Hany S. Ibrahim, Soha R. Abdelhadi, and Hatem A. Abdel-Aziz Copyright © 2015 Hany S. Ibrahim et al. All rights reserved.