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Int. J. Mol. Sci., Volume 11, Issue 4 (April 2010) – 37 articles , Pages 1190-1972

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1211 KiB  
Article
Electrochemical Analysis of Conducting Polymer Thin Films
by Ritesh N. Vyas and Bin Wang
Int. J. Mol. Sci. 2010, 11(4), 1956-1972; https://doi.org/10.3390/ijms11041956 - 26 Apr 2010
Cited by 40 | Viewed by 16175
Abstract
Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material [...] Read more.
Polyelectrolyte multilayers built via the layer-by-layer (LbL) method has been one of the most promising systems in the field of materials science. Layered structures can be constructed by the adsorption of various polyelectrolyte species onto the surface of a solid or liquid material by means of electrostatic interaction. The thickness of the adsorbed layers can be tuned precisely in the nanometer range. Stable, semiconducting thin films are interesting research subjects. We use a conducting polymer, poly(p-phenylene vinylene) (PPV), in the preparation of a stable thin film via the LbL method. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize the ionic conductivity of the PPV multilayer films. The ionic conductivity of the films has been found to be dependent on the polymerization temperature. The film conductivity can be fitted to a modified Randle’s circuit. The circuit equivalent calculations are performed to provide the diffusion coefficient values. Full article
(This article belongs to the Special Issue Conjugated Polymers)
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870 KiB  
Article
Effects of Aflatoxin B1 and Fumonisin B1 on the Viability and Induction of Apoptosis in Rat Primary Hepatocytes
by Deise H. B. Ribeiro, Fabiane L. Ferreira, Valéria N. Da Silva, Simone Aquino and Benedito Corrêa
Int. J. Mol. Sci. 2010, 11(4), 1944-1955; https://doi.org/10.3390/ijms11041944 - 26 Apr 2010
Cited by 46 | Viewed by 12315
Abstract
The present study evaluated the effect of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) either alone, or in association, on rat primary hepatocyte cultures. Cell viability was assessed by flow cytometry after propidium iodine intercalation. DNA fragmentation [...] Read more.
The present study evaluated the effect of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) either alone, or in association, on rat primary hepatocyte cultures. Cell viability was assessed by flow cytometry after propidium iodine intercalation. DNA fragmentation and apoptosis were assessed by agarose gel electrophoresis and acridine orange and ethidium bromide staining. At the concentrations of AFB1 and FB1 used, the toxins did not decrease cell viability, but did induce apoptosis in a concentration and time-dependent manner. Full article
(This article belongs to the Section Biochemistry)
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1366 KiB  
Review
Hub Promiscuity in Protein-Protein Interaction Networks
by Ashwini Patil, Kengo Kinoshita and Haruki Nakamura
Int. J. Mol. Sci. 2010, 11(4), 1930-1943; https://doi.org/10.3390/ijms11041930 - 26 Apr 2010
Cited by 128 | Viewed by 15514 | Correction
Abstract
Hubs are proteins with a large number of interactions in a protein-protein interaction network. They are the principal agents in the interaction network and affect its function and stability. Their specific recognition of many different protein partners is of great interest from the [...] Read more.
Hubs are proteins with a large number of interactions in a protein-protein interaction network. They are the principal agents in the interaction network and affect its function and stability. Their specific recognition of many different protein partners is of great interest from the structural viewpoint. Over the last few years, the structural properties of hubs have been extensively studied. We review the currently known features that are particular to hubs, possibly affecting their binding ability. Specifically, we look at the levels of intrinsic disorder, surface charge and domain distribution in hubs, as compared to non-hubs, along with differences in their functional domains. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
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6068 KiB  
Review
Excited-State Dynamics of Overlapped Optically-Allowed 1Bu+ and Optically-Forbidden 1Bu- or 3Ag- Vibronic Levels of Carotenoids: Possible Roles in the Light-Harvesting Function
by Yasushi Koyama, Yoshinori Kakitani, Takeshi Miki, Rebecca Christiana and Hiroyoshi Nagae
Int. J. Mol. Sci. 2010, 11(4), 1888-1929; https://doi.org/10.3390/ijms11041888 - 26 Apr 2010
Cited by 24 | Viewed by 10729
Abstract
The unique excited-state properties of the overlapped (diabatic) optically-allowed 1Bu+ and the optically-forbidden 1Bu- or 3Ag- vibronic levels close to conical intersection (‘the diabatic pair’) are summarized: Pump-probe spectroscopy after selective excitation with ~100 fs pulses of [...] Read more.
The unique excited-state properties of the overlapped (diabatic) optically-allowed 1Bu+ and the optically-forbidden 1Bu- or 3Ag- vibronic levels close to conical intersection (‘the diabatic pair’) are summarized: Pump-probe spectroscopy after selective excitation with ~100 fs pulses of all-trans carotenoids (Cars) in nonpolar solvent identified a symmetry selection rule in the diabatic electronic mixing and diabatic internal conversion, i.e., ‘1Bu+-to-1Bu- is allowed but 1Bu+-to-3Ag- is forbidden’. On the other hand, pump-probe spectroscopy after coherent excitation with ~30 fs of all-trans Cars in THF generated stimulated emission with quantum beat, consisting of the long-lived coherent diabatic cross term and a pair of short-lived incoherent terms. Full article
(This article belongs to the Section Biochemistry)
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324 KiB  
Review
Porphyrinic Molecular Devices: Towards Nanoscaled Processes
by Melissa J. Latter and Steven J. Langford
Int. J. Mol. Sci. 2010, 11(4), 1878-1887; https://doi.org/10.3390/ijms11041878 - 26 Apr 2010
Cited by 23 | Viewed by 11599
Abstract
The structural, coordinative, photochemical and electrochemical properties of the porphyrin macrocycle that make them the functional element of choice in ubiquitous biological systems, e.g., chlorophyll, cytochrome P450 and hemoglobin, also contribute to making porphyrins and metalloporphyrins desirable in a “bottom-up” approach to the [...] Read more.
The structural, coordinative, photochemical and electrochemical properties of the porphyrin macrocycle that make them the functional element of choice in ubiquitous biological systems, e.g., chlorophyll, cytochrome P450 and hemoglobin, also contribute to making porphyrins and metalloporphyrins desirable in a “bottom-up” approach to the construction of nanosized devices. This paper highlights some recent advances in the construction of supramolecular assemblies based on the porphyrin macrocycle that display optically readable functions as a result of photonic or chemical stimuli. Full article
(This article belongs to the Special Issue Molecular Machines and Nanomachines)
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914 KiB  
Article
Synthesis of a Novel Biodegradable Polyurethane with Phosphatidylcholines
by Jun Cao, Niancao Chen, Yuanwei Chen and Xianglin Luo
Int. J. Mol. Sci. 2010, 11(4), 1870-1877; https://doi.org/10.3390/ijms11041870 - 26 Apr 2010
Cited by 13 | Viewed by 11802
Abstract
A novel polyurethane was successfully synthesized by chain-extension of biodegradable poly (L-lactide) functionalized phosphatidylcholine (PC) with hexamethylene diisocyanate (HDI) as chain extender (PUR-PC). The molecular weights, glass transition temperature (Tg) increased significantly after the chain-extension. The hydrophilicity of PUR-PC was better than the [...] Read more.
A novel polyurethane was successfully synthesized by chain-extension of biodegradable poly (L-lactide) functionalized phosphatidylcholine (PC) with hexamethylene diisocyanate (HDI) as chain extender (PUR-PC). The molecular weights, glass transition temperature (Tg) increased significantly after the chain-extension. The hydrophilicity of PUR-PC was better than the one without PC, according to a water absorption test. Moreover, the number of adhesive platelets and anamorphic platelets on PUR-PC film were both less than those on PUR film. These preliminary results suggest that this novel polyurethane might be a better scaffold than traditional biodegradable polyurethanes for tissue engineering due to its better blood compatibility. Besides, this study also provides a new method to prepare PC-modified biodegradable polyurethanes. Full article
(This article belongs to the Section Biochemistry)
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408 KiB  
Article
Functionality and Antioxidant Properties of Tilapia (Oreochromis niloticus) as Influenced by the Degree of Hydrolysis
by Mohamed Beva Kelfala Foh, Issoufou Amadou, Betty Mabel Foh, Mohamed Tabita Kamara and Wenshui Xia
Int. J. Mol. Sci. 2010, 11(4), 1851-1869; https://doi.org/10.3390/ijms11041851 - 26 Apr 2010
Cited by 111 | Viewed by 16728
Abstract
Freeze dried protein powders (Fresh minced meat, FMM and Hot water dip, HWD) from tilapia (Oreochromis niloticus) were hydrolyzed by Alcalase 2.4 L (Alc), Flavourzyme (Flav) and Neutrase (Neut), and investigated for antioxidant activity and their functional properties. FMM and HWD [...] Read more.
Freeze dried protein powders (Fresh minced meat, FMM and Hot water dip, HWD) from tilapia (Oreochromis niloticus) were hydrolyzed by Alcalase 2.4 L (Alc), Flavourzyme (Flav) and Neutrase (Neut), and investigated for antioxidant activity and their functional properties. FMM and HWD hydrolysed by Alc, exhibiting superior antioxidant activity, had estimated degrees of hydrolysis (DH) of 23.40% and 25.43%, respectively. The maximum values of the 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 3-(2-pyridyl) 5,6-bis(4-phenyl-sulphonic acid)-1,2,4-triazine (ferrozine), radical scavenging activities and metal chelating properties were 86.67%, 91.27% and 82.57%, and 84.67%, 92.60% and 78.00% for FMM and HWD, respectively, with a significant difference (P < 0.05) between the samples. Essential amino acids were above the amounts recommended by the Food and Agricultural Organization/World Health Organization (FAO/WHO/UNU) for humans. Lower molecular weight sizes <3,000 Da were more predominant in FMM and HWD hydrolysed by Alc, while in hydrolysed by Flav and Neut they were >8,000 Da. At pH 2, FMM and HWD hydrolysates have varying solubilities above 85% (Alc FMM; 91.33%, Flav FMM; 79.5%, Neut FMM; 83.8% and Alc HWD; 90.45%, Flav HWD; 83.5%, and Neut HWD; 85.8%). They have ‘U’ shaped solubility curves, water holding capacity was in the range of 2.77 and 1.77 mL/g, while oil holding capacity ranged between 3.13 and 2.23 mL/g. FMM and HWD have the highest bulk density of 0.53 and 0.53 for Neutrase and Alcalase 2.4 L, respectively. Foam capacity and stability ranged from 125.5 to 61.4, 138.5 to 45.2, 130.0 to 62.5, and 124.5 to 55.0, 137.5 to 53.3, 129.6 to 62.7 for FMM and HWD hydrolyzed with Alcalase 2.4 L, Flavourzyme and Neutrase, respectively. Tilapia fish protein hydrolysates are thus potential functional food ingredients. Full article
(This article belongs to the Section Biochemistry)
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168 KiB  
Article
β-Sitosterol: Supercritical Carbon Dioxide Extraction from Sea Buckthorn (Hippophae rhamnoides L.) Seeds
by Marie Sajfrtová, Ivana Ličková, Martina Wimmerová, Helena Sovová and Zdeněk Wimmer
Int. J. Mol. Sci. 2010, 11(4), 1842-1850; https://doi.org/10.3390/ijms11041842 - 22 Apr 2010
Cited by 71 | Viewed by 12504
Abstract
Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15–60 MPa and temperatures of 40-80 °C. Oil [...] Read more.
Supercritical fluid extraction represents an efficient and environmentally friendly technique for isolation of phytosterols from different plant sources. Sea buckthorn (Hippophae rhamnoides L.) seeds were extracted with supercritical carbon dioxide at pressures ranging from 15–60 MPa and temperatures of 40-80 °C. Oil and β-sitosterol yields were measured in the extraction course and compared with Soxhlet extraction with hexane. The average yield of β-sitosterol was 0.31 mg/g of seeds. The maximum concentration of β-sitosterol in the extract, 0.5% w/w, was achieved at 15 MPa, 40 °C, and a carbon dioxide consumption of 50 g/g of seeds. The extraction rate was maximal at 60 MPa and 40 °C. Both β-sitosterol yield and its concentration in the extract obtained with hexane were lower than with carbon dioxide. Full article
(This article belongs to the Special Issue Supercritical Carbon Dioxide)
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392 KiB  
Article
Physico-Chemical Properties and Phase Behaviour of Pyrrolidinium-Based Ionic Liquids
by Urszula Domańska
Int. J. Mol. Sci. 2010, 11(4), 1825-1841; https://doi.org/10.3390/ijms11041825 - 21 Apr 2010
Cited by 38 | Viewed by 11659
Abstract
A review of the relevant literature on 1-alkyl-1-methylpyrrolidinium-based ionic liquids has been presented. The phase diagrams for the binary systems of {1-ethyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [EMPYR][CF3SO3] + water, or + 1-butanol} and for the binary systems of {1-propyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [...] Read more.
A review of the relevant literature on 1-alkyl-1-methylpyrrolidinium-based ionic liquids has been presented. The phase diagrams for the binary systems of {1-ethyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [EMPYR][CF3SO3] + water, or + 1-butanol} and for the binary systems of {1-propyl-1-methylpyrrolidinium trifluoromethanesulfonate (triflate) [PMPYR][CF3SO3] + water, or + an alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol)} have been determined at atmospheric pressure using a dynamic method. The influence of alcohol chain length was discussed for the [PMPYR][CF3SO3]. A systematic decrease in the solubility was observed with an increase of the alkyl chain length of an alcohol. (Solid + liquid) phase equilibria with complete miscibility in the liquid phase region were observed for the systems involving water and alcohols. The solubility of the ionic liquid increases as the alkyl chain length on the pyrrolidinium cation increases. The correlation of the experimental data has been carried out using the Wilson, UNIQUAC and the NRTL equations. The phase diagrams reported here have been compared to the systems published earlier with the 1-alkyl-1-methylpyrrolidinium-based ionic liquids. The influence of the cation and anion on the phase behaviour has been discussed. The basic thermal properties of pure ILs, i.e., melting temperature and the enthalpy of fusion, the solid-solid phase transition temperature and enthalpy have been measured using a differential scanning microcalorimetry technique. Full article
(This article belongs to the Special Issue Advances in Green Chemistry and Sustainable Chemistry)
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539 KiB  
Review
Intrinsically Disordered Proteins in Bcl-2 Regulated Apoptosis
by Gilles J. P. Rautureau, Catherine L. Day and Mark G. Hinds
Int. J. Mol. Sci. 2010, 11(4), 1808-1824; https://doi.org/10.3390/ijms11041808 - 16 Apr 2010
Cited by 65 | Viewed by 15710
Abstract
Intrinsic cell death is mediated by interaction between pro-apoptotic and pro-survival proteins of the B-cell lymphoma-2 (Bcl-2) family. Members of this family are either intrinsically disordered or contain intrinsically disordered regions/domains that are critical to their function. Alternate splicing and post-translational modifications can [...] Read more.
Intrinsic cell death is mediated by interaction between pro-apoptotic and pro-survival proteins of the B-cell lymphoma-2 (Bcl-2) family. Members of this family are either intrinsically disordered or contain intrinsically disordered regions/domains that are critical to their function. Alternate splicing and post-translational modifications can determine the extent of these disordered regions and are critical for regulating Bcl-2 proteins. Conformational plasticity and structural transitions characterize the interactions within the Bcl-2 family, with conserved sequence motifs on both binding partners required for their molecular recognition. Full article
(This article belongs to the Special Issue Advances in Molecular Recognition)
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532 KiB  
Article
Synthesis of Hydrophilic and Amphiphilic Acryl Sucrose Monomers and Their Copolymerisation with Styrene, Methylmethacrylate and α- and β-Pinenes
by Maria Teresa Barros, Krasimira T. Petrova and Raj P. Singh
Int. J. Mol. Sci. 2010, 11(4), 1792-1807; https://doi.org/10.3390/ijms11041792 - 16 Apr 2010
Cited by 14 | Viewed by 11740
Abstract
Herein, we report the synthesis of monomethacryloyl sucrose esters, and their successful free radical homo- and co-polymerisation with styrene, methylmethacrylate, α- and β-pinene. The chemical, physical, structural and surface chemical properties of these polymers, containing a hydrophobic olefin backbone and hydrophilic sugar moieties [...] Read more.
Herein, we report the synthesis of monomethacryloyl sucrose esters, and their successful free radical homo- and co-polymerisation with styrene, methylmethacrylate, α- and β-pinene. The chemical, physical, structural and surface chemical properties of these polymers, containing a hydrophobic olefin backbone and hydrophilic sugar moieties as side chains, have been investigated. Biodegradation tests of the copolymer samples by a microbial fungal culture (Aspergillus niger) method showed good biodegradability. The chemical structure and surface chemistry of the synthesized homo- and co-polymers demonstrate their potential technological relevance as amphiphilic and biodegradable polymers. Full article
(This article belongs to the Special Issue Advances in Green Chemistry and Sustainable Chemistry)
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236 KiB  
Article
Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems
by Cláudia L. S. Louros, Ana Filipa M. Cláudio, Catarina M. S. S. Neves, Mara G. Freire, Isabel M. Marrucho, Jérôme Pauly and João A. P. Coutinho
Int. J. Mol. Sci. 2010, 11(4), 1777-1791; https://doi.org/10.3390/ijms11041777 - 15 Apr 2010
Cited by 174 | Viewed by 15164
Abstract
Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K [...] Read more.
Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, were measured and are reported. The studied phosphonium-based ILs have shown to be more effective in promoting ABS compared to the imidazolium-based counterparts with similar anions. Moreover, the extractive capability of such systems was assessed for distinct biomolecules (including amino acids, food colourants and alkaloids). Densities and viscosities of both aqueous phases, at the mass fraction compositions used for the biomolecules extraction, were also determined. The evaluated IL-based ABS have been shown to be prospective extraction media, particularly for hydrophobic biomolecules, with several advantages over conventional polymer-inorganic salt ABS. Full article
(This article belongs to the Special Issue Advances in Green Chemistry and Sustainable Chemistry)
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367 KiB  
Review
Paramagnetic Liposome Nanoparticles for Cellular and Tumour Imaging
by Nazila Kamaly and Andrew D. Miller
Int. J. Mol. Sci. 2010, 11(4), 1759-1776; https://doi.org/10.3390/ijms11041759 - 15 Apr 2010
Cited by 68 | Viewed by 16724
Abstract
In this review we discuss the development of paramagnetic liposomes incorporating MRI contrast agents and show how these are utilized in cellular imaging in vitro. Bi-functional, bi-modal imaging paramagnetic liposome systems are also described. Next we discuss the upgrading of paramagnetic liposomes [...] Read more.
In this review we discuss the development of paramagnetic liposomes incorporating MRI contrast agents and show how these are utilized in cellular imaging in vitro. Bi-functional, bi-modal imaging paramagnetic liposome systems are also described. Next we discuss the upgrading of paramagnetic liposomes into bi-modal imaging neutral nanoparticles for in vivo imaging applications. We discuss the development of such systems and show how paramagnetic liposomes and imaging nanoparticles could be developed as platforms for future multi-functional, multi-modal imaging theranostic nanodevices tailor-made for the combined imaging of early stage disease pathology and functional drug delivery. Full article
(This article belongs to the Special Issue Magnetic Nanoparticles)
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916 KiB  
Article
Engineering Cofactor Preference of Ketone Reducing Biocatalysts: A Mutagenesis Study on a γ-Diketone Reductase from the Yeast Saccharomyces cerevisiae Serving as an Example
by Michael Katzberg, Nàdia Skorupa-Parachin, Marie-Françoise Gorwa-Grauslund and Martin Bertau
Int. J. Mol. Sci. 2010, 11(4), 1735-1758; https://doi.org/10.3390/ijms11041735 - 14 Apr 2010
Cited by 21 | Viewed by 14803
Abstract
The synthesis of pharmaceuticals and catalysts more and more relies on enantiopure chiral building blocks. These can be produced in an environmentally benign and efficient way via bioreduction of prochiral ketones catalyzed by dehydrogenases. A productive source of these biocatalysts is the yeast [...] Read more.
The synthesis of pharmaceuticals and catalysts more and more relies on enantiopure chiral building blocks. These can be produced in an environmentally benign and efficient way via bioreduction of prochiral ketones catalyzed by dehydrogenases. A productive source of these biocatalysts is the yeast Saccharomyces cerevisiae, whose genome also encodes a reductase catalyzing the sequential reduction of the γ-diketone 2,5-hexanedione furnishing the diol (2S,5S)-hexanediol and the γ-hydroxyketone (5S)-hydroxy-2-hexanone in high enantio- as well as diastereoselectivity (ee and de >99.5%). This enzyme prefers NADPH as the hydrogen donating cofactor. As NADH is more stable and cheaper than NADPH it would be more effective if NADH could be used in cell-free bioreduction systems. To achieve this, the cofactor binding site of the dehydrogenase was altered by site-directed mutagenesis. The results show that the rational approach based on a homology model of the enzyme allowed us to generate a mutant enzyme having a relaxed cofactor preference and thus is able to use both NADPH and NADH. Results obtained from other mutants are discussed and point towards the limits of rationally designed mutants. Full article
(This article belongs to the Special Issue Biocatalysis)
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611 KiB  
Article
Diversity of Phylogenetic Information According to the Locus and the Taxonomic Level: An Example from a Parasitic Mesostigmatid Mite Genus
by Lise Roy, Ashley P. G. Dowling, Claude Marie Chauve and Thierry Buronfosse
Int. J. Mol. Sci. 2010, 11(4), 1704-1734; https://doi.org/10.3390/ijms11041704 - 13 Apr 2010
Cited by 28 | Viewed by 11847
Abstract
Molecular markers for cladistic analyses may perform differently according to the taxonomic group considered and the historical level under investigation. Here we evaluate the phylogenetic potential of five different markers for resolving evolutionary relationships within the ectoparasitic genus Dermanyssus at the species level, [...] Read more.
Molecular markers for cladistic analyses may perform differently according to the taxonomic group considered and the historical level under investigation. Here we evaluate the phylogenetic potential of five different markers for resolving evolutionary relationships within the ectoparasitic genus Dermanyssus at the species level, and their ability to address questions about the evolution of specialization. COI provided 9–18% divergence between species (up to 9% within species), 16S rRNA 10–16% (up to 4% within species), ITS1 and 2 2–9% (up to 1% within species) and Tropomyosin intron n 8–20% (up to 6% within species). EF-1a revealed different non-orthologous copies withinindividuals of Dermanyssus and Ornithonyssus. Tropomyosin intron n was shown containing consistent phylogenetic signal at the specific level within Dermanyssus and represents a promising marker for future prospects in phylogenetics of Acari. Phylogenetic analyses revealed that the generalist condition is apomorphic and D. gallinae mightrepresent a complex of hybridized lineages. The split into hirsutus-group and gallinae-group in Dermanyssus does not seem to be appropriate based upon these results and D. longipes appears to be composed of two different entities. Full article
(This article belongs to the Special Issue Cladistic Analysis and Molecular Evolution)
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180 KiB  
Review
Flavanols and Anthocyanins in Cardiovascular Health: A Review of Current Evidence
by Sonia De Pascual-Teresa, Diego A. Moreno and Cristina García-Viguera
Int. J. Mol. Sci. 2010, 11(4), 1679-1703; https://doi.org/10.3390/ijms11041679 - 13 Apr 2010
Cited by 493 | Viewed by 40773
Abstract
Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects [...] Read more.
Nowadays it is accepted that natural flavonoids present in fruits and plant-derived-foods are relevant, not only for technological reasons and organoleptic properties, but also because of their potential health-promoting effects, as suggested by the available experimental and epidemiological evidence. The beneficial biological effects of these food bioactives may be driven by two of their characteristic properties: their affinity for proteins and their antioxidant activity. Over the last 15 years, numerous publications have demonstrated that besides their in vitro antioxidant capacity, certain phenolic compounds, such as anthocyanins, catechins, proanthocyanidins, and other non coloured flavonoids, may regulate different signaling pathways involved in cell survival, growth and differentiation. In this review we will update the knowledge on the cardiovascular effects of anthocyanins, catechins and proanthocyanidins, as implied by the in vitro and clinical studies on these compounds. We also review the available information on the structure, distribution and bioavailability of flavanols (monomeric catechins and proanthocyanidins) and anthocyanins, data necessary in order to understand their role in reducing risk factors and preventing cardiovascular health problems through different aspects of their bioefficacy on vascular parameters (platelet agregation, atherosclerosis, blood pressure, antioxidant status, inflammation-related markers, etc.), myocardial conditions, and whole-body metabolism (serum biochemistry, lipid profile), highlighting the need for better-designed clinical studies to improve the current knowledge on the potential health benefits of these flavonoids to cardiovascular and metabolic health. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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637 KiB  
Review
Dental Implant Systems
by Yoshiki Oshida, Elif B. Tuna, Oya Aktören and Koray Gençay
Int. J. Mol. Sci. 2010, 11(4), 1580-1678; https://doi.org/10.3390/ijms11041580 - 12 Apr 2010
Cited by 178 | Viewed by 27477
Abstract
Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As [...] Read more.
Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. Full article
(This article belongs to the Special Issue Dental Materials)
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1356 KiB  
Review
Chromatin Fiber Dynamics under Tension and Torsion
by Christophe Lavelle, Jean-Marc Victor and Jordanka Zlatanova
Int. J. Mol. Sci. 2010, 11(4), 1557-1579; https://doi.org/10.3390/ijms11041557 - 12 Apr 2010
Cited by 50 | Viewed by 15065
Abstract
Genetic and epigenetic information in eukaryotic cells is carried on chromosomes, basically consisting of large compact supercoiled chromatin fibers. Micromanipulations have recently led to great advances in the knowledge of the complex mechanisms underlying the regulation of DNA transaction events by nucleosome and [...] Read more.
Genetic and epigenetic information in eukaryotic cells is carried on chromosomes, basically consisting of large compact supercoiled chromatin fibers. Micromanipulations have recently led to great advances in the knowledge of the complex mechanisms underlying the regulation of DNA transaction events by nucleosome and chromatin structural changes. Indeed, magnetic and optical tweezers have allowed opportunities to handle single nucleosomal particles or nucleosomal arrays and measure their response to forces and torques, mimicking the molecular constraints imposed in vivo by various molecular motors acting on the DNA. These challenging technical approaches provide us with deeper understanding of the way chromatin dynamically packages our genome and participates in the regulation of cellular metabolism. Full article
(This article belongs to the Special Issue Single Molecules)
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308 KiB  
Article
Colon-Specific Drug Delivery Behavior of pH-Responsive PMAA/Perlite Composite
by Mehrdad Mahkam and Laleh Vakhshouri
Int. J. Mol. Sci. 2010, 11(4), 1546-1556; https://doi.org/10.3390/ijms11041546 - 12 Apr 2010
Cited by 28 | Viewed by 12822
Abstract
The preparation, characterization, and in vitro release of 5-aminosalicylic acid (5-ASA)from methacrylic acid (MAA)/perlite composites (APC) prepared via a sol–gel route are reported. The free-radical graft polymerization of methacrylic acid (MAA) onto perlite particles was studied experimentally. The grafting procedure consisted of surface [...] Read more.
The preparation, characterization, and in vitro release of 5-aminosalicylic acid (5-ASA)from methacrylic acid (MAA)/perlite composites (APC) prepared via a sol–gel route are reported. The free-radical graft polymerization of methacrylic acid (MAA) onto perlite particles was studied experimentally. The grafting procedure consisted of surface activation with 3-(trimethoxysilyl) propyl methacrylate (TSPA), followed by free-radical graft polymerization of methacrylic acid (MAA) in ethyl acetate with 2,2΄-azobis-isobutyronitrile (AIBN) initiator. The composition of the composites hybrid materials was determined by FTIR spectroscopy. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). The dried composites were immersed in a saturated solution of 5-ASA in water overnight and dried over a period of three days at room temperature and the in vitro release profiles were established separately in both (SGF, pH 1) and (SIF, pH 7.4). The 5-ASA concentration of the solution was measured using a UV-Vis spectrophotometer (205 nm) at different time intervals. The in vitro drug release test revealed that the release rate of 5-ASA in buffer solutions increased with the silica content in the composites; on the contrary, the increase of the content of 3-(trimethoxysilyl)propyl methacrylate (TSPA), a coupling agent, decreased the drug release rate. Full article
(This article belongs to the Special Issue Composite Materials)
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377 KiB  
Review
Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures
by Mao-Kuo Wei, Chii-Wann Lin, Chih-Chung Yang, Yean-Woei Kiang, Jiun-Haw Lee and Hoang-Yan Lin
Int. J. Mol. Sci. 2010, 11(4), 1527-1545; https://doi.org/10.3390/ijms11041527 - 12 Apr 2010
Cited by 64 | Viewed by 19076
Abstract
In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs) and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design [...] Read more.
In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs) and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode. Full article
(This article belongs to the Special Issue Conjugated Polymers)
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452 KiB  
Review
Oxidative Stress, Molecular Inflammation and Sarcopenia
by Si-Jin Meng and Long-Jiang Yu
Int. J. Mol. Sci. 2010, 11(4), 1509-1526; https://doi.org/10.3390/ijms11041509 - 12 Apr 2010
Cited by 424 | Viewed by 22805
Abstract
Sarcopenia is the decline of muscle mass and strength with age. Evidence suggests that oxidative stress and molecular inflammation play important roles in age-related muscle atrophy. The two factors may interfere with the balance between protein synthesis and breakdown, cause mitochondrial dysfunction, and [...] Read more.
Sarcopenia is the decline of muscle mass and strength with age. Evidence suggests that oxidative stress and molecular inflammation play important roles in age-related muscle atrophy. The two factors may interfere with the balance between protein synthesis and breakdown, cause mitochondrial dysfunction, and induce apoptosis. The purpose of this review is to discuss some of the major signaling pathways that are activated or inactivated during the oxidative stress and molecular inflammation seen in aged skeletal muscle. Combined interventions that may be required to reverse sarcopenia, such as exercise, caloric restriction, and nutrition, will also be discussed. Full article
(This article belongs to the Section Biochemistry)
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1072 KiB  
Review
Acetylene-Based Materials in Organic Photovoltaics
by Fabio Silvestri and Assunta Marrocchi
Int. J. Mol. Sci. 2010, 11(4), 1471-1508; https://doi.org/10.3390/ijms11041471 - 8 Apr 2010
Cited by 105 | Viewed by 17510
Abstract
Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. [...] Read more.
Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices. Full article
(This article belongs to the Special Issue Solar Cells)
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380 KiB  
Article
Titanium Immobilized with an Antimicrobial Peptide Derived from Histatin Accelerates the Differentiation of Osteoblastic Cell Line, MC3T3-E1
by Seicho Makihira, Takahiro Shuto, Hiroki Nikawa, Keishi Okamoto, Yuichi Mine, Yuko Takamoto, Masaru Ohara and Koichiro Tsuji
Int. J. Mol. Sci. 2010, 11(4), 1458-1470; https://doi.org/10.3390/ijms11041458 - 2 Apr 2010
Cited by 25 | Viewed by 11725
Abstract
The objective of this study was to evaluate the effect of titanium immobilized with a cationic antimicrobial peptide (JH8194) derived from histatin on the biofilm formation of Porphyromonas gingivalis and differentiation of osteoblastic cells (MC3T3-E1). The titanium specimens (Ti) were immobilized with JH8194, [...] Read more.
The objective of this study was to evaluate the effect of titanium immobilized with a cationic antimicrobial peptide (JH8194) derived from histatin on the biofilm formation of Porphyromonas gingivalis and differentiation of osteoblastic cells (MC3T3-E1). The titanium specimens (Ti) were immobilized with JH8194, according to the method previously described. The colonization of P. gingivalis on JH8194-Ti was significantly lower than that on control- and blocking-Ti. JH8194-Ti enhanced the mRNA expressions of Runx2 and OPN, and ALPase activity in the MC3T3-E1, as compared with those of control- and blocking-Ti. These results, taken together, suggested the possibility that JH8194-Ti may be a potential aid to shorten the period of acquiring osseointegration. Full article
(This article belongs to the Special Issue Dental Materials)
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173 KiB  
Article
Origin and Distribution of Thiophenes and Furans in Gas Discharges from Active Volcanoes and Geothermal Systems
by Franco Tassi, Giordano Montegrossi, Francesco Capecchiacci and Orlando Vaselli
Int. J. Mol. Sci. 2010, 11(4), 1434-1457; https://doi.org/10.3390/ijms11041434 - 31 Mar 2010
Cited by 26 | Viewed by 13387
Abstract
The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S [...] Read more.
The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal gas discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
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201 KiB  
Article
Differential Proteomics Identification of HSP90 as Potential Serum Biomarker in Hepatocellular Carcinoma by Two-dimensional Electrophoresis and Mass Spectrometry
by Yiyi Sun, Zhihe Zang, Xiaohong Xu, Zhonglin Zhang, Ling Zhong, Wang Zan, Yan Zhao and Lin Sun
Int. J. Mol. Sci. 2010, 11(4), 1423-1433; https://doi.org/10.3390/ijms11041423 - 31 Mar 2010
Cited by 45 | Viewed by 12012
Abstract
The aim of the current study is to identify the potential biomarkers involved in Hepatocellular carcinoma (HCC) carcinogenesis. A comparative proteomics approach was utilized to identify the differentially expressed proteins in the serum of 10 HCC patients and 10 controls. A total of [...] Read more.
The aim of the current study is to identify the potential biomarkers involved in Hepatocellular carcinoma (HCC) carcinogenesis. A comparative proteomics approach was utilized to identify the differentially expressed proteins in the serum of 10 HCC patients and 10 controls. A total of 12 significantly altered proteins were identified by mass spectrometry. Of the 12 proteins identified, HSP90 was one of the most significantly altered proteins and its over-expression in the serum of 20 HCC patients was confirmed using ELISA analysis. The observations suggest that HSP90 might be a potential biomarker for early diagnosis, prognosis, and monitoring in the therapy of HCC. This work demonstrates that a comprehensive strategy of proteomic identification combined with further validation should be adopted in the field of cancer biomarker discovery. Full article
(This article belongs to the Special Issue Biomarkers)
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260 KiB  
Article
In Vivo Study of the Effects of Peptide-Conjugated Near-Infrared Fluorescent Quantum Dots on the Tumorigenic and Lymphatic Metastatic Capacities of Squamous Cell Carcinoma Cell Line Tca8113 and U14
by Zhi-Gang Li, Kai Yang, Yu-An Cao, Gang Zheng, De-Ping Sun, Cheng Zhao and Jia Yang
Int. J. Mol. Sci. 2010, 11(4), 1413-1422; https://doi.org/10.3390/ijms11041413 - 31 Mar 2010
Cited by 13 | Viewed by 12005
Abstract
Quantum dots (QDs) have great potential in non-invasive monitoring and imaging of tumor cells in vivo, but it is unknown if QDs affect their tumorigenesis and metastasis. Here, we applied peptide-conjugated near-infrared fluorescent QDs (NIRF-QDs) to label the squamous cell carcinoma cells [...] Read more.
Quantum dots (QDs) have great potential in non-invasive monitoring and imaging of tumor cells in vivo, but it is unknown if QDs affect their tumorigenesis and metastasis. Here, we applied peptide-conjugated near-infrared fluorescent QDs (NIRF-QDs) to label the squamous cell carcinoma cells Tca8113 and U14. We tested the proliferation and apoptotic capacities of both cells, and the capacity of cervical lymph node metastasis after tumorigenesis in U14 cells’. We find that QDs do not affect the tumor cells’ capacities to grow, proliferate, and metastasize. Our study provides critical data to support the application of NIRF-QDs in non-invasive monitoring and imaging of tumor cells in vivo. Full article
(This article belongs to the Section Biochemistry)
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111 KiB  
Article
Escherichia coli mar and acrAB Mutants Display No Tolerance to Simple Alcohols
by Jonas Ankarloo, Susanne Wikman and Ian A. Nicholls
Int. J. Mol. Sci. 2010, 11(4), 1403-1412; https://doi.org/10.3390/ijms11041403 - 31 Mar 2010
Cited by 26 | Viewed by 10768
Abstract
The inducible Mar phenotype of Escherichia coli is associated with increased tolerance to multiple hydrophobic antibiotics as well as some highly hydrophobic organic solvents such as cyclohexane, mediated mainly through the AcrAB/TolC efflux system. The influence of water miscible alcohols ethanol and 1-propanol [...] Read more.
The inducible Mar phenotype of Escherichia coli is associated with increased tolerance to multiple hydrophobic antibiotics as well as some highly hydrophobic organic solvents such as cyclohexane, mediated mainly through the AcrAB/TolC efflux system. The influence of water miscible alcohols ethanol and 1-propanol on a Mar constitutive mutant and a mar deletion mutant of E. coli K-12, as well as the corresponding strains carrying the additional acrAB deletion, was investigated. In contrast to hydrophobic solvents, all strains were killed in exponential phase by 1-propanol and ethanol at rates comparable to the parent strain. Thus, the Mar phenotype does not protect E. coli from killing by these more polar solvents. Surprisingly, AcrAB does not contribute to an increased alcohol tolerance. In addition, sodium salicylate, at concentrations known to induce the mar operon, was unable to increase 1-propanol or ethanol tolerance. Rather, the toxicity of both solvents was increased in the presence of sodium salicylate. Collectively, the results imply that the resilience of E. coli to water miscible alcohols, in contrast to more hydrophobic solvents, does not depend upon the AcrAB/TolC efflux system, and suggests a lower limit for substrate molecular size and functionality. Implications for the application of microbiological systems in environments containing high contents of water miscible organic solvents, e.g.,phage display screening, are discussed. Full article
(This article belongs to the Section Biochemistry)
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312 KiB  
Review
Impact of Dietary Polyphenols on Carbohydrate Metabolism
by Kati Hanhineva, Riitta Törrönen, Isabel Bondia-Pons, Jenna Pekkinen, Marjukka Kolehmainen, Hannu Mykkänen and Kaisa Poutanen
Int. J. Mol. Sci. 2010, 11(4), 1365-1402; https://doi.org/10.3390/ijms11041365 - 31 Mar 2010
Cited by 916 | Viewed by 50532
Abstract
Polyphenols, including flavonoids, phenolic acids, proanthocyanidins and resveratrol, are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. Growing evidence indicates that various dietary polyphenols may influence carbohydrate metabolism at [...] Read more.
Polyphenols, including flavonoids, phenolic acids, proanthocyanidins and resveratrol, are a large and heterogeneous group of phytochemicals in plant-based foods, such as tea, coffee, wine, cocoa, cereal grains, soy, fruits and berries. Growing evidence indicates that various dietary polyphenols may influence carbohydrate metabolism at many levels. In animal models and a limited number of human studies carried out so far, polyphenols and foods or beverages rich in polyphenols have attenuated postprandial glycemic responses and fasting hyperglycemia, and improved acute insulin secretion and insulin sensitivity. The possible mechanisms include inhibition of carbohydrate digestion and glucose absorption in the intestine, stimulation of insulin secretion from the pancreatic b-cells, modulation of glucose release from the liver, activation of insulin receptors and glucose uptake in the insulin-sensitive tissues, and modulation of intracellular signalling pathways and gene expression. The positive effects of polyphenols on glucose homeostasis observed in a large number of in vitro and animal models are supported by epidemiological evidence on polyphenol-rich diets. To confirm the implications of polyphenol consumption for prevention of insulin resistance, metabolic syndrome and eventually type 2 diabetes, human trials with well-defined diets, controlled study designs and clinically relevant end-points together with holistic approaches e.g., systems biology profiling technologies are needed. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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366 KiB  
Article
Dynamic Rheological Studies of Poly(p-phenyleneterephthalamide) and Carbon Nanotube Blends in Sulfuric Acid
by Yutong Cao, Zhaofeng Liu, Xianghua Gao, Junrong Yu, Zuming Hu and Ziqi Liang
Int. J. Mol. Sci. 2010, 11(4), 1352-1364; https://doi.org/10.3390/ijms11041352 - 31 Mar 2010
Cited by 7 | Viewed by 11268
Abstract
We have studied the dynamic scanning of liquid-crystalline(LC) poly(p-phenyleneterephthalamide) sulfuric acid (PPTA-H2SO4) solution, and its blend with single-walled carbon nanotubes (SWNTs), by using a flat plate rotational rheometer. The effects of weight concentration and molecular weight of [...] Read more.
We have studied the dynamic scanning of liquid-crystalline(LC) poly(p-phenyleneterephthalamide) sulfuric acid (PPTA-H2SO4) solution, and its blend with single-walled carbon nanotubes (SWNTs), by using a flat plate rotational rheometer. The effects of weight concentration and molecular weight of PPTA, as well as operating temperature, on dynamic viscoelasticity of the PPTA-H2SO4 LCsolution system are discussed. The transition from a biphasic system to a single-phase LC occurs in the weight concentration range of SWNTs from 0.1% to 0.2%, in which complex viscosity reaches the maximum at 0.2 wt% and the minimum at 0.1 wt%, respectively, of SWNTs. With increasing SWNT weight concentration, the endothermic peak temperature increases from 73.6 to 79.9 °C. The PPTA/SWNT/H2SO4 solution is in its plateau zone and storage modulus (G´) is a dominant factor within the frequency (ω) range of 0.1–10 rad/s. As w increases, the G´ rises slightly, in direct proportion to the w. The loss modulus (G´´) does not rise as a function of ω when ω < 1 s−1, then when ω > 1 s−1 G´´ increases faster than G´, yet not in any proportion to the ω. Full article
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213 KiB  
Article
Gas-Phase Synthesis of Dimethyl Carbonate from Methanol and Carbon Dioxide Over Co1.5PW12O40 Keggin-Type Heteropolyanion
by Ahmed Aouissi, Zeid Abdullah Al-Othman and Amro Al-Amro
Int. J. Mol. Sci. 2010, 11(4), 1343-1351; https://doi.org/10.3390/ijms11041343 - 31 Mar 2010
Cited by 45 | Viewed by 15698
Abstract
The reactivity of Co1.5PW12O40 in the direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH was investigated. The synthesized catalyst has been characterized by means of FTIR, XRD, TG, and DTA and tested in [...] Read more.
The reactivity of Co1.5PW12O40 in the direct synthesis of dimethyl carbonate (DMC) from CO2 and CH3OH was investigated. The synthesized catalyst has been characterized by means of FTIR, XRD, TG, and DTA and tested in gas phase under atmospheric pressure. The effects of the reaction temperature, time on stream, and methanol weight hourly space velocity (MWHSV) on the conversion and DMC selectivity were investigated. The highest conversion (7.6%) and highest DMC selectivity (86.5%) were obtained at the lowest temperature used (200 °C). Increasing the space velocity MWHSV increased the selectivity of DMC, but decreased the conversion. A gain of 18.4% of DMC selectivity was obtained when the MWHSV was increased from 0.65 h-1 to 3.2 h-1. Full article
(This article belongs to the Section Physical Chemistry, Theoretical and Computational Chemistry)
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