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Int. J. Mol. Sci., Volume 10, Issue 12 (December 2009), Pages 5104-5527

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Research

Jump to: Review

Open AccessArticle Formation Energies of Antiphase Boundaries in GaAs and GaP: An ab Initio Study
Int. J. Mol. Sci. 2009, 10(12), 5104-5114; doi:10.3390/ijms10125104
Received: 1 August 2009 / Revised: 13 October 2009 / Accepted: 6 November 2009 / Published: 25 November 2009
Cited by 15 | PDF Full-text (1441 KB) | HTML Full-text | XML Full-text
Abstract
Electronic and structural properties of antiphase boundaries in group III-V semiconductor compounds have been receiving increased attention due to the potential to integration of optically-active III-V heterostructures on silicon or germanium substrates. The formation energies of {110}, {111}, {112}, and {113} antiphase boundaries in GaAs and GaP were studied theoretically using a full-potential linearized augmented plane-wave density-functional approach. Results of the study reveal that the stoichiometric {110} boundaries are the most energetically favorable in both compounds. The specific formation energy γ of the remaining antiphase boundaries increases in the order of γf113g ≈ γf112g < γf111g, which suggests {113} and {112} as possible planes for faceting and annihilation of antiphase boundaries in GaAs and GaP. Full article
(This article belongs to the Special Issue Applications of Density Functional Theory)
Open AccessArticle Enzymatic Reactions in Near Critical CO2: The Effect of Pressure on Phenol Removal by Tyrosinase
Int. J. Mol. Sci. 2009, 10(12), 5217-5223; doi:10.3390/ijms10125217
Received: 14 August 2009 / Revised: 9 November 2009 / Accepted: 16 November 2009 / Published: 1 December 2009
Cited by 7 | PDF Full-text (182 KB) | HTML Full-text | XML Full-text
Abstract
The use of enzymes in supercritical CO2 (SCCO2) has received extensive attention in recent years. Biocatalysts have the advantage of substrate specificity and SCCO2 offers several advantages over liquid solvents. This work deals with the utilization of SCCO [...] Read more.
The use of enzymes in supercritical CO2 (SCCO2) has received extensive attention in recent years. Biocatalysts have the advantage of substrate specificity and SCCO2 offers several advantages over liquid solvents. This work deals with the utilization of SCCO2 as a medium for the enzymatic removal of phenol from aqueous solutions using tyrosinase. Since the presence of oxygen is crucial for the enzyme-catalyzed oxidation, the substantial solvating power of SCCO2 makes it a promising medium for such reactions. The conversion of phenol was higher at 10 MPa. Under near critical conditions (7 MPa, 35 ºC), the addition of air at 5 × 105 Pa of pressure improved phenol removal. Full article
(This article belongs to the Special Issue Supercritical Carbon Dioxide)
Open AccessArticle Functionality, in Vitro Digestibility and Physicochemical Properties of Two Varieties of Defatted Foxtail Millet Protein Concentrates
Int. J. Mol. Sci. 2009, 10(12), 5224-5238; doi:10.3390/ijms10125224
Received: 21 September 2009 / Revised: 25 November 2009 / Accepted: 27 November 2009 / Published: 1 December 2009
Cited by 25 | PDF Full-text (291 KB) | HTML Full-text | XML Full-text
Abstract
Two varieties of foxtail millet protein concentrates (white and yellow) were characterized for in vitro trypsin digestibility, functional and physicochemical properties. Millet protein concentrate was easily digested by trypsin in vitro. Essential amino acids were above the amounts recommended by the [...] Read more.
Two varieties of foxtail millet protein concentrates (white and yellow) were characterized for in vitro trypsin digestibility, functional and physicochemical properties. Millet protein concentrate was easily digested by trypsin in vitro. Essential amino acids were above the amounts recommended by the Food Agricultural Organization/World Health Organization (FAO/WHO/UNU) for humans. Yellow millet protein concentrate (YMPC) possessed the highest differential scanning calorimetry result (peak temperature of 88.98 °C, delta H = 0.01 J/g), white millet protein concentrate (WMPC) had the lowest (peak temperature 84.06 °C, delta H = 0.10 J/g). The millet protein concentrates had molecular sizes around 14.4 and 97.4 kDa. They have U-shape solubility curves. Waterbinding capacity was in the range of 5.0 and 7.0 g/g, while oil absorption capacity ranged between 4.8 and 5.9 g/g. WMPC had higher bulk density (0.22 g/mL) and emulsifying capacity than YMPC and Soy Protein Concentrate (SPC). Foam capacity and foam stability ranged from 137 to 73 g/mL for WMPC, from 124 to 61 g/mL SPC and from 124 to 46 g/mL for YMPC. Millet protein concentrates are potential functional food ingredients. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Identification of Different Donor-Acceptor Structures via Förster Resonance Energy Transfer (FRET) in Quantum-Dot-Perylene Bisimide Assemblies
Int. J. Mol. Sci. 2009, 10(12), 5239-5256; doi:10.3390/ijms10125239
Received: 21 October 2009 / Revised: 23 November 2009 / Accepted: 27 November 2009 / Published: 1 December 2009
Cited by 17 | PDF Full-text (1537 KB) | HTML Full-text | XML Full-text
Abstract
Nanoassemblies are formed via self-assembly of ZnS capped CdSe quantum dots (QD) and perylene bisimide (PBI) dyes. Upon assembly formation the QD photoluminescence is quenched, as can be detected both via single particle detection and ensemble experiments in solution. Quenching has been [...] Read more.
Nanoassemblies are formed via self-assembly of ZnS capped CdSe quantum dots (QD) and perylene bisimide (PBI) dyes. Upon assembly formation the QD photoluminescence is quenched, as can be detected both via single particle detection and ensemble experiments in solution. Quenching has been assigned to FRET and NON-FRET processes. Analysis of FRET allows for a distinction between different geometries of the QD dye assemblies. Time-resolved single molecule spectroscopy reveals intrinsic fluctuations of the PBI fluorescence lifetime and spectrum, caused by rearrangement of the phenoxy side groups. The distribution of such molecular conformations and their changed dynamics upon assembly formation are discussed in the scope of FRET efficiency and surface ligand density. Full article
(This article belongs to the Special Issue Single Molecules)
Open AccessArticle Microwave Effect for Glycosylation Promoted by Solid Super Acid in Supercritical Carbon Dioxide
Int. J. Mol. Sci. 2009, 10(12), 5285-5295; doi:10.3390/ijms10125285
Received: 27 October 2009 / Revised: 9 November 2009 / Accepted: 5 December 2009 / Published: 8 December 2009
Cited by 8 | PDF Full-text (290 KB) | HTML Full-text | XML Full-text
Abstract
The effects of microwave irradiation (2.45 GHz, 200 W) on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive [...] Read more.
The effects of microwave irradiation (2.45 GHz, 200 W) on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule. Full article
(This article belongs to the Special Issue Supercritical Carbon Dioxide)
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Open AccessArticle On the Physical Meaning of the Isothermal Titration Calorimetry Measurements in Calorimeters with Full Cells
Int. J. Mol. Sci. 2009, 10(12), 5296-5325; doi:10.3390/ijms10125296
Received: 7 October 2009 / Revised: 6 November 2009 / Accepted: 8 December 2009 / Published: 9 December 2009
Cited by 9 | PDF Full-text (188 KB) | HTML Full-text | XML Full-text
Abstract
We have performed a detailed study of the thermodynamics of the titration Process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation ΔH [...] Read more.
We have performed a detailed study of the thermodynamics of the titration Process in an isothermal titration calorimeter with full cells. We show that the relationship between the enthalpy and the heat measured is better described in terms of the equation ΔH = Winj + Q (where Winj is the work necessary to carry out the titration) than in terms of ΔH = Q. Moreover, we show that the heat of interaction between two components is related to the partial enthalpy of interaction at infinite dilution of the titrant component, as well as to its partial volume of interaction at infinite dilution. Full article
(This article belongs to the Special Issue Isothermal Titration Calorimetry)
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Open AccessArticle Effects of Genetic, Pre- and Post-Harvest Factors on Phenolic Content and Antioxidant Capacity of White Asparagus Spears
Int. J. Mol. Sci. 2009, 10(12), 5370-5380; doi:10.3390/ijms10125370
Received: 2 November 2009 / Accepted: 14 December 2009 / Published: 16 December 2009
Cited by 10 | PDF Full-text (165 KB) | HTML Full-text | XML Full-text
Abstract
The effects of genetic, pre-harvest (season of harvest, spear diameter, spear portion and spear tip color) and post-harvest factors (storage and domestic preparation practices, e.g., peeling and cooking) on total phenolic, flavonoid and ascorbic acid content of white asparagus spears and their [...] Read more.
The effects of genetic, pre-harvest (season of harvest, spear diameter, spear portion and spear tip color) and post-harvest factors (storage and domestic preparation practices, e.g., peeling and cooking) on total phenolic, flavonoid and ascorbic acid content of white asparagus spears and their correlation with antioxidant capacity (DPPH and FRAP) were studied. Results showed that genetic material was important for the total phenolic content but not season of harvest, spear diameter or storage. Violet spear tips and apical spear portions showed the largest amount of total phenolics. Peeling did not affect total phenolics in fresh asparagus, whereas it reduced their content in stored asparagus, while cooking resulted in an increase in both fresh and stored asparagus. However, the soluble extract of total phenolics and flavonoids were minor and the missing significance of phenolics and flavonoids in antioxidant capacity of white asparagus spears depends on these small amounts. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle A Study of the Crystallization, Melting, and Foaming Behaviors of Polylactic Acid in Compressed CO2
Int. J. Mol. Sci. 2009, 10(12), 5381-5397; doi:10.3390/ijms10125381
Received: 27 October 2009 / Revised: 26 November 2009 / Accepted: 14 December 2009 / Published: 16 December 2009
Cited by 65 | PDF Full-text (258 KB) | HTML Full-text | XML Full-text
Abstract
The crystallization and melting behaviors of linear polylactic acid (PLA) treated by compressed CO2 was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO2 exposure significantly increased PLA’s crystallization rate; a [...] Read more.
The crystallization and melting behaviors of linear polylactic acid (PLA) treated by compressed CO2 was investigated. The isothermal crystallization test indicated that while PLA exhibited very low crystallization kinetics under atmospheric pressure, CO2 exposure significantly increased PLA’s crystallization rate; a high crystallinity of 16.5% was achieved after CO2 treatment for only 1 min at 100 °C and 6.89 MPa. One melting peak could be found in the DSC curve, and this exhibited a slight dependency on treatment times, temperatures, and pressures. PLA samples tended to foam during the gas release process, and a foaming window as a function of time and temperature was established. Based on the foaming window, crystallinity, and cell morphology, it was found that foaming clearly reduced the needed time for PLA’s crystallization equilibrium. Full article
(This article belongs to the Special Issue Supercritical Carbon Dioxide)
Open AccessArticle Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase
Int. J. Mol. Sci. 2009, 10(12), 5398-5410; doi:10.3390/ijms10125398
Received: 5 November 2009 / Revised: 14 December 2009 / Accepted: 17 December 2009 / Published: 18 December 2009
Cited by 12 | PDF Full-text (259 KB) | HTML Full-text | XML Full-text
Abstract
Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of [...] Read more.
Dihydrofolate reductase (DHFR) is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (-)-epigallocatechin gallate (EGCG) and (-)-epicatechin gallate (ECG) are potent inhibitors of DHFR with dissociation constants (KD) of 0.9 and 1.8 μM, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (-)-epigallocatechin (EGC) and (-)-epicatechin (EC)] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl)-(-)-epicatechin; TMECG), which effectively binds to DHFR (KD = 2.1 μM). In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a KD of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a KD of 0.6 μM. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle The Study of the Inhibition of the Recombinant TACE Prodomain to Endotoxemia in Mice
Int. J. Mol. Sci. 2009, 10(12), 5442-5454; doi:10.3390/ijms10125442
Received: 9 October 2009 / Accepted: 17 December 2009 / Published: 18 December 2009
Cited by 3 | PDF Full-text (539 KB) | HTML Full-text | XML Full-text
Abstract
Objective: To demonstrate the inhibitory function of the prodomain of tumor necrosis factor-α (TNF-α) converting enzyme (TACE) on TACE activity and to develop an approach to interfere with inflammation processes. Methods: The cDNA encoding the fulllength ectodomain (T1300) and prodomain (T591) of [...] Read more.
Objective: To demonstrate the inhibitory function of the prodomain of tumor necrosis factor-α (TNF-α) converting enzyme (TACE) on TACE activity and to develop an approach to interfere with inflammation processes. Methods: The cDNA encoding the fulllength ectodomain (T1300) and prodomain (T591) of TACE were amplified by RT-PCR. The expression plasmids (pET-28a (+)-T1300 and pET-28a (+)-T591) were constructed and transformed into E. coli BL21. After Ni2+-NTA resin affinity chromatography, the recombinant T591 protein was obtained and assayed. In order to detect its inhibiton of TACE activity, the mice in the LPS-induced endotoxemia model group were treated with the recombinant TACE prodomain protein prior to the injection of LPS. Murine peritoneal macrophages were isolated from mice abdominal cavity for FCM and the liver, kidney and lung were removed for traditionally histopathology sectioning. Results: The FCM results showed that the recombinant prodomain protein decreased the release of the sTNF-α, which mediated the accumulation of TNF-α on the surface of macrophage cells. HE staining proved that the recombinant protein can decrease the inflammatory response in internal organs of endotoxaemia mice. Conclusions: The recombinant prodomain of TACE has the ability to inhibit sTNF-α release, which indicates that prodomain is an effective antagonist of TACE and might be useful in the molecular design of anti-inflammatory drugs. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
Open AccessArticle Sharp Phylogeographic Breaks and Patterns of Genealogical Concordance in the Brine Shrimp Artemia franciscana
Int. J. Mol. Sci. 2009, 10(12), 5455-5470; doi:10.3390/ijms10125455
Received: 1 December 2009 / Revised: 16 December 2009 / Accepted: 17 December 2009 / Published: 18 December 2009
Cited by 15 | PDF Full-text (242 KB) | HTML Full-text | XML Full-text
Abstract
Genealogical concordance is a critical overlay of all phylogenetic analyses, irrespective of taxonomic level. To assess such patterns of congruence we have compiled and derived sequence data for two mitochondrial (16S rRNA, COI) and two nuclear (ITS1, p26) markers in 14 American [...] Read more.
Genealogical concordance is a critical overlay of all phylogenetic analyses, irrespective of taxonomic level. To assess such patterns of congruence we have compiled and derived sequence data for two mitochondrial (16S rRNA, COI) and two nuclear (ITS1, p26) markers in 14 American populations of the hypersaline branchiopod Artemia franciscana. Cladistic analysis revealed three reciprocally monophyletic mitochondrial clades. For nuclear DNA, incomplete lineage sorting was evident presumably as a result of slower coalescence or male-mediated dispersal. Our findings capture the genealogical interval between gene splitting and population divergence. In this sense, strong indications are provided in favour of a superspecies status and ongoing speciation in A. franciscana. Full article
(This article belongs to the Special Issue Cladistic Analysis and Molecular Evolution)
Open AccessArticle Immune Response among Patients Exposed to Molds
Int. J. Mol. Sci. 2009, 10(12), 5471-5484; doi:10.3390/ijms10125471
Received: 7 November 2009 / Revised: 11 December 2009 / Accepted: 16 December 2009 / Published: 21 December 2009
Cited by 6 | PDF Full-text (264 KB) | HTML Full-text | XML Full-text
Abstract
Macrocyclic trichothecenes, mycotoxins produced by Stachybotrys chartarum, have been implicated in adverse reactions in individuals exposed to mold-contaminated environments. Cellular and humoral immune responses and the presence of trichothecenes were evaluated in patients with mold-related health complaints. Patients underwent history, physical [...] Read more.
Macrocyclic trichothecenes, mycotoxins produced by Stachybotrys chartarum, have been implicated in adverse reactions in individuals exposed to mold-contaminated environments. Cellular and humoral immune responses and the presence of trichothecenes were evaluated in patients with mold-related health complaints. Patients underwent history, physical examination, skin prick/puncture tests with mold extracts, immunological evaluations and their sera were analyzed for trichothecenes. T-cell proliferation, macrocyclic trichothecenes, and mold specific IgG and IgA levels were not significantly different than controls; however 70% of the patients had positive skin tests to molds. Thus, IgE mediated or other non-immune mechanisms could be the cause of their symptoms. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle Chelation of Cu(II), Zn(II), and Fe(II) by Tannin Constituents of Selected Edible Nuts
Int. J. Mol. Sci. 2009, 10(12), 5485-5497; doi:10.3390/ijms10125485
Received: 23 October 2009 / Revised: 24 November 2009 / Accepted: 21 December 2009 / Published: 22 December 2009
Cited by 30 | PDF Full-text (322 KB) | HTML Full-text | XML Full-text
Abstract
The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited [...] Read more.
The tannin fractions isolated from hazelnuts, walnuts and almonds were characterised by colorimetric assays and by an SE-HPLC technique. The complexation of Cu(II) and Zn(II) was determined by the reaction with tetramethylmurexide, whereas for Fe(II), ferrozine was employed. The walnut tannins exhibited a significantly weaker reaction with the vanillin/HCl reagent than hazelnut and almond tannins, but the protein precipitation capacity of the walnut fraction was high. The SE-HPLC chromatogram of the tannin fraction from hazelnuts revealed the presence of oligomers with higher molecular weights compared to that of almonds. Copper ions were most effectively chelated by the constituents of the tannin fractions of hazelnuts, walnuts and almonds. At a 0.2 mg/assay addition level, the walnut tannins complexed almost 100% Cu(II). The Fe(II) complexation capacities of the tannin fractions of walnuts and hazelnuts were weaker in comparison to that of the almond tannin fraction, which at a 2.5 mg/assay addition level, bound Fe(II) by ~90%. The capacity to chelate Zn(II) was quite varied for the different nut tannin fractions: almond tannins bound as much as 84% Zn(II), whereas the value for walnut tannins was only 8.7%; and for hazelnut tannins, no Zn(II) chelation took place at the levels tested. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
Open AccessArticle Contributions of the C-Terminal Helix to the Structural Stability of a Hyperthermophilic Fe-Superoxide Dismutase (TcSOD)
Int. J. Mol. Sci. 2009, 10(12), 5498-5512; doi:10.3390/ijms10125498
Received: 18 November 2009 / Revised: 16 December 2009 / Accepted: 17 December 2009 / Published: 23 December 2009
Cited by 5 | PDF Full-text (495 KB) | HTML Full-text | XML Full-text
Abstract
Hyperthermophilic superoxide dismutases (SODs) are of particular interest due to their potential industrial importance and scientific merit in studying the molecular mechanisms of protein folding and stability. Compared to the mesophilic SODs, the hyperthermostable Fe-SODs (TcSOD and ApSOD) have an extended [...] Read more.
Hyperthermophilic superoxide dismutases (SODs) are of particular interest due to their potential industrial importance and scientific merit in studying the molecular mechanisms of protein folding and stability. Compared to the mesophilic SODs, the hyperthermostable Fe-SODs (TcSOD and ApSOD) have an extended C-terminal helix, which forms an additional ion-pairing network. In this research, the role of the extended C-terminus in the structural stability of TcSOD was studied by investigating the properties of two deletion mutants. The results indicated that the ion-pairing network at the C-terminus had limited contributions to the stability of TcSOD against heat- and GdnHClinduced inactivation. The intactness of the C-terminal helix had dissimilar impact on the two stages of TcSOD unfolding induced by guanidinium chloride. The mutations slightly decreased the Gibbs free energy of the dissociation of the tetrameric enzymes, while greatly affected the stability of the molten globule-like intermediate. These results suggested that the additional ion-pairing network mainly enhanced the structural stability of TcSOD by stabilizing the monomers. Full article
(This article belongs to the Section Biochemistry, Molecular Biology and Biophysics)
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Open AccessArticle Antioxidant Activity of a Red Lentil Extract and Its Fractions
Int. J. Mol. Sci. 2009, 10(12), 5513-5527; doi:10.3390/ijms10125513
Received: 1 December 2009 / Revised: 16 December 2009 / Accepted: 17 December 2009 / Published: 23 December 2009
Cited by 42 | PDF Full-text (222 KB) | HTML Full-text | XML Full-text
Abstract
Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of [...] Read more.
Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, was obtained using acetone-water (1:1; v/v) as the mobile phase. Phenolic compounds present in the crude extract and its fractions demonstrated antioxidant and antiradical activities as revealed from studies using a β-carotene-linoleate model system, the total antioxidant activity (TAA) method, the DPPH radical-scavenging activity assay, and a reducing power evaluation. Results of these assays showed the highest values when tannins (fraction 2) were tested. For instance, the TAA of the tannin fraction was 5.85 μmol Trolox® eq./mg, whereas the crude extract and fraction 1 showed 0.68 and 0.33 μmol Trolox® eq./mg, respectively. The content of total phenolics in fraction 2 was the highest (290 mg/g); the tannin content, determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g, was 129. There were 24 compounds identified in the crude extract using an HPLC-ESI-MS method: quercetin diglycoside, catechin, digallate procyanidin, and p-hydroxybenzoic were the dominant phenolics in the extract. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)

Review

Jump to: Research

Open AccessReview Effect of Interface Structure on Mechanical Properties of Advanced Composite Materials
Int. J. Mol. Sci. 2009, 10(12), 5115-5134; doi:10.3390/ijms10125115
Received: 13 October 2009 / Revised: 21 November 2009 / Accepted: 24 November 2009 / Published: 25 November 2009
Cited by 19 | PDF Full-text (812 KB) | HTML Full-text | XML Full-text
Abstract
This paper deals with the effect of interface structures on the mechanical properties of fiber reinforced composite materials. First, the background of research, development and applications on hybrid composite materials is introduced. Second, metal/polymer composite bonded structures are discussed. Then, the rationale [...] Read more.
This paper deals with the effect of interface structures on the mechanical properties of fiber reinforced composite materials. First, the background of research, development and applications on hybrid composite materials is introduced. Second, metal/polymer composite bonded structures are discussed. Then, the rationale is given for nanostructuring the interface in composite materials and structures by introducing nanoscale features such as nanopores and nanofibers. The effects of modifying matrices and nano-architecturing interfaces on the mechanical properties of nanocomposite materials are examined. A nonlinear damage model for characterizing the deformation behavior of polymeric nanocomposites is presented and the application of this model to carbon nanotube-reinforced and reactive graphite nanotube-reinforced epoxy composite materials is shown. Full article
(This article belongs to the Special Issue Composite Materials)
Open AccessReview A Review of Computational Methods in Materials Science: Examples from Shock-Wave and Polymer Physics
Int. J. Mol. Sci. 2009, 10(12), 5135-5216; doi:10.3390/ijms10125135
Received: 22 September 2009 / Revised: 23 October 2009 / Accepted: 19 November 2009 / Published: 1 December 2009
Cited by 11 | PDF Full-text (27285 KB) | HTML Full-text | XML Full-text
Abstract
This review discusses several computational methods used on different length and time scales for the simulation of material behavior. First, the importance of physical modeling and its relation to computer simulation on multiscales is discussed. Then, computational methods used on different scales [...] Read more.
This review discusses several computational methods used on different length and time scales for the simulation of material behavior. First, the importance of physical modeling and its relation to computer simulation on multiscales is discussed. Then, computational methods used on different scales are shortly reviewed, before we focus on the molecular dynamics (MD) method. Here we survey in a tutorial-like fashion some key issues including several MD optimization techniques. Thereafter, computational examples for the capabilities of numerical simulations in materials research are discussed. We focus on recent results of shock wave simulations of a solid which are based on two different modeling approaches and we discuss their respective assets and drawbacks with a view to their application on multiscales. Then, the prospects of computer simulations on the molecular length scale using coarse-grained MD methods are covered by means of examples pertaining to complex topological polymer structures including star-polymers, biomacromolecules such as polyelectrolytes and polymers with intrinsic stiffness. This review ends by highlighting new emerging interdisciplinary applications of computational methods in the field of medical engineering where the application of concepts of polymer physics and of shock waves to biological systems holds a lot of promise for improving medical applications such as extracorporeal shock wave lithotripsy or tumor treatment. Full article
(This article belongs to the Special Issue Algorithms and Molecular Sciences)
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Open AccessReview Investigations on the Mechanical Properties of Conducting Polymer Coating-Substrate Structures and Their Influencing Factors
Int. J. Mol. Sci. 2009, 10(12), 5257-5284; doi:10.3390/ijms10125257
Received: 19 October 2009 / Revised: 21 November 2009 / Accepted: 3 December 2009 / Published: 8 December 2009
Cited by 18 | PDF Full-text (1481 KB) | HTML Full-text | XML Full-text
Abstract
This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coatingsubstrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In [...] Read more.
This review covers recent advances and work on the microstructure features, mechanical properties and cracking processes of conducting polymer film/coatingsubstrate structures under different testing conditions. An attempt is made to characterize and quantify the relationships between mechanical properties and microstructure features. In addition, the film cracking mechanism on the micro scale and some influencing factors that play a significant role in the service of the film-substrate structure are presented. These investigations cover the conducting polymer film/coating nucleation process, microstructure-fracture characterization, translation of brittle-ductile fractures, and cracking processes near the largest inherent macromolecule defects under thermal-mechanical loadings, and were carried out using in situ scanning electron microscopy (SEM) observations, as a novel method for evaluation of interface strength and critical failure stress. Full article
(This article belongs to the Special Issue Composite Materials)
Open AccessReview The Hunt for Natural Skin Whitening Agents
Int. J. Mol. Sci. 2009, 10(12), 5326-5349; doi:10.3390/ijms10125326
Received: 5 November 2009 / Revised: 24 November 2009 / Accepted: 9 December 2009 / Published: 10 December 2009
Cited by 50 | PDF Full-text (166 KB) | HTML Full-text | XML Full-text
Abstract
Skin whitening products are commercially available for cosmetic purposes in order to obtain a lighter skin appearance. They are also utilized for clinical treatment of pigmentary disorders such as melasma or postinflammatory hyperpigmentation. Whitening agents act at various levels of melanin production [...] Read more.
Skin whitening products are commercially available for cosmetic purposes in order to obtain a lighter skin appearance. They are also utilized for clinical treatment of pigmentary disorders such as melasma or postinflammatory hyperpigmentation. Whitening agents act at various levels of melanin production in the skin. Many of them are known as competitive inhibitors of tyrosinase, the key enzyme in melanogenesis. Others inhibit the maturation of this enzyme or the transport of pigment granules (melanosomes) from melanocytes to surrounding keratinocytes. In this review we present an overview of (natural) whitening products that may decrease skin pigmentation by their interference with the pigmentary processes. Full article
Open AccessReview Recent Progress of Flower Colour Modification by Biotechnology
Int. J. Mol. Sci. 2009, 10(12), 5350-5369; doi:10.3390/ijms10125350
Received: 17 November 2009 / Revised: 10 December 2009 / Accepted: 14 December 2009 / Published: 15 December 2009
Cited by 54 | PDF Full-text (214 KB) | HTML Full-text | XML Full-text
Abstract
Genetically-modified, colour-altered varieties of the important cut-flower crop carnation have now been commercially available for nearly ten years. In this review we describe the manipulation of the anthocyanin biosynthesis pathway that has lead to the development of these varieties and how similar [...] Read more.
Genetically-modified, colour-altered varieties of the important cut-flower crop carnation have now been commercially available for nearly ten years. In this review we describe the manipulation of the anthocyanin biosynthesis pathway that has lead to the development of these varieties and how similar manipulations have been successfully applied to both pot plants and another cut-flower species, the rose. From this experience it is clear that down- and up-regulation of the flavonoid and anthocyanin pathway is both possible and predictable. The major commercial benefit of the application of this technology has so far been the development of novel flower colours through the development of transgenic varieties that produce, uniquely for the target species, anthocyanins derived from delphinidin. These anthocyanins are ubiquitous in nature, and occur in both ornamental plants and common food plants. Through the extensive regulatory approval processes that must occur for the commercialization of genetically modified organisms, we have accumulated considerable experimental and trial data to show the accumulation of delphinidin based anthocyanins in the transgenic plants poses no environmental or health risk. Full article
(This article belongs to the Special Issue Phenolics and Polyphenolics)
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Open AccessReview Cell Culture on MEMS Platforms: A Review
Int. J. Mol. Sci. 2009, 10(12), 5411-5441; doi:10.3390/ijms10125411
Received: 13 November 2009 / Revised: 13 December 2009 / Accepted: 16 December 2009 / Published: 18 December 2009
Cited by 71 | PDF Full-text (245 KB) | HTML Full-text | XML Full-text
Abstract
Microfabricated systems provide an excellent platform for the culture of cells, and are an extremely useful tool for the investigation of cellular responses to various stimuli. Advantages offered over traditional methods include cost-effectiveness, controllability, low volume, high resolution, and sensitivity. Both biocompatible [...] Read more.
Microfabricated systems provide an excellent platform for the culture of cells, and are an extremely useful tool for the investigation of cellular responses to various stimuli. Advantages offered over traditional methods include cost-effectiveness, controllability, low volume, high resolution, and sensitivity. Both biocompatible and bioincompatible materials have been developed for use in these applications. Biocompatible materials such as PMMA or PLGA can be used directly for cell culture. However, for bioincompatible materials such as silicon or PDMS, additional steps need to be taken to render these materials more suitable for cell adhesion and maintenance. This review describes multiple surface modification strategies to improve the biocompatibility of MEMS materials. Basic concepts of cell-biomaterial interactions, such as protein adsorption and cell adhesion are covered. Finally, the applications of these MEMS materials in Tissue Engineering are presented. Full article
(This article belongs to the Special Issue Biocompatibility of Materials)

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