Report-Physicochemical and Antimicrobial properties of canola (Brassica napus L.) seed oil.

Canola oil has been used in the Pakistan for the treatment of various diseases and skin infections. Oil was extracted with n-hexane from the seeds of canola (Brassica napus L.) and was evaluated for free fatty acid value. Four microorganisms namely; Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas originals, and Klebsiella pneumonia, has known to cause some infections treatable with these oils were investigated. The results showed that all oil shown inhibitory effects against Klebsiella pneumoniae, Staphylococcus epidermidis, and Pseudomonas originals but no inhibitory effects was found against Staphylococcus aureus.

The Clinical Applications of Polymer Gel Dosimetry Using MRI.

Polymer gel dosimeters are devices that utilize the radiation-induced polymerization reactions of vinyl monomers in a gel to store information of radiation dose. They have some advantages over other dosimeters as the visual conformation and the direct read-out of three-dimensional (3D) radiation dose information for the dosimetric verification of intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic radiotherapy (SRT) with steep dose gradients. In this report, the dosimetric uncertainties and potential for clinical applications of polymer gel dosimetry by the in-house developed 3D dose verification system for IMRT and VMAT QA is outlined.

[The evaluation of unsaturation of blood lipids using methods of physical chemistry and clinical biochemistry. The insulin regulation of metabolism of fatty acids, number of double binds and cell absorption of glucose].

It is supposed that the main cause of insulin synthesis at late stages of phylogenesis became discrepancy between increase in vivo need in energy and physical chemical parameters of palmitic saturated fatty acid; its transportation to cells in composition of lipoproteins in optimal quantity (more than 15% of all fatty acids) became in vivo unfeasible. The biological role of insulin consists in supporting of insulin-dependent cells (skeletal miocytes in the first place) with substrates for gaining energy. The hormone transforms all palmitic saturated fatty acid endogenously synthesized from glucose into specific for animal cells rn-9 C18:1 oleic mono unsaturated fatty acid. The endogenous mono unsaturated fatty acid is oxidized by mitohondria with the highest constant of reaction velocity gaining for cells optimal quantity of biotransforming energy in the form of ATP. The insulin expresses in hepatocytes synthesis of oleic triglycerides and formation of oleic lipoproteins of very low density that only insulin-dependent cells absorb using apoE/B-100-endocytosis. The insulin expresses synthesis of Palmitoyl-KoA-elongase, stearyl-KoA-desaturase and glucose transporters 4, activates glucose absorption by cells with the purpose of synthesis endogenous oleic saturated fatty acid. The insulin substitutes in vivo ineffective palmitic alternative of metabolism of fatty acids for potentially more effective oleic metabolism of fatty acids. The insulin increases unsaturation of fatty acids and number of double binds in them. This can be established by direct titration of double binds by ozone on the basis of quantitative detection of fatty acids using technique of gas chromatography and calculating ratio C16:1/C16:0, C18:1/C18:0 and C18:1/C16:0. The diabetes mellitus is a disorder of metabolism of mono unsaturated fatty acid in the first place and only in the second place pathology of glucose absorption by cells.

Lipase-catalyzed hydrolysis of linseed oil: optimization using response surface methodology.

Lipase-catalyzed hydrolysis of linseed oil was investigated. Four commercially available microbial lipases of Lipase AY, Lipozyme RMIM, Lipozyme TLIM, and Novozym 435 were used. Among these tested lipases, Lipase AY exhibited the best hydrolysis effeciency to linseed oil. The effect of reaction variables was also evaluated and optimized using response surface methodology. A second-order regression for the Box-Behken design was used to study the effect of five independent variables, such as, temperature, pH, oil-aqueous phase ratio, enzyme load, and reaction time, on the hydrolysis of linseed oil. The optimal conditions were as follows: temperature 33°C, pH 5.80, oil-aqueous phase ratio 0.90 (w/w), enzyme load 1.20% (relative to the weight of total substrates), and reaction time 3.33 h. Under these conditions, the hydrolysis ratio of linseed oil was 93.92±0.54%.

Interplay of experiment and theory: determination of an accurate equilibrium structure of 1-methyluracil by the gas electron diffraction method and coupled-cluster computations.

As far as fundamental knowledge is concerned, the methyl derivatives of uracil can be considered as the simplest objects for studying the structural effects due to the substitution in the pyrimidyne nucleobases. From this point of view, 1-methyluracil is of special importance in biochemistry because uracil attaches ribose in ribonucleic acid (RNA) just precisely at the N1 atom. The semi-experimental equilibrium structure (r(e)(se)) of 1-methyluracil has been determined for the first time by the gas electron diffraction (GED) method taking into account rovibrational corrections to the thermal-average internuclear distances calculated with harmonic and anharmonic (cubic) MP2/cc-pVTZ force constants with consideration of the methyl torsion as a large-amplitude motion. For the first time, the structure of the molecule has been optimized by the very time-consuming coupled-cluster method with single and double excitations and perturbative treatment of connected triples using the correlation-consistent polarized weighted core-valence triple-ζ basis set with all electrons being correlated (CCSD(T)(all)/cc-pwCVTZ) and extrapolated to the complete basis set (CBS) with the help of the MP2 calculations. Small differences between similar bond lengths of equilibrium configurations were assumed in the GED analysis at the CCSD(T)(all)/CBS values. A remarkable agreement between the semi-experimental and computed equilibrium structures points out the high accuracy of both the GED determination and the coupled-cluster computations. The effect of methylation on the structure of uracil has been analyzed.

Surface charge-switchable polymeric magnetic nanoparticles for the controlled release of anticancer drug.

We develop paclitaxel (PTX) and magnetic nanoparticles (MNPs) coencapsulated, surface charge-switchable, thermosensitive poly(d,l-lactic-co-glycolic acid)-l-lysine-d-galactose (PTX-MNP-PLGA-Lys-Gal) NPs for the controlled release of the anticancer drug. The novel dual signal-responsive nanovehicle is formulated to shield off target at pH 7.4 but bind avidly to tumor cells in acidity, alleviating toxicity and side effects of the drug to normal tissues. The mechanism involves pH-sensitive NPs surface charge switching by the deblocking process of galactose molecules followed by protonation of ε-NH2 in lysine residue at acidic pH. Magnetic hyperthermia under near infrared (NIR) irradiation induced the contraction of PTX-MNP-PLGA-Lys-Gal NPs and, in turn, triggered burst release of PTX. Transmission electron microscopy (TEM), fluorescence microscope analyses, Fourier transform infrared (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), dynamic light scattering (DLS), and ξ-potential analyses were performed to characterize physicochemical properties of the as-prepared NPs. The size range of the globule PTX-MNP-PLGA-Lys-Gal NPs after being prescreened was from 130 to 150 nm under simulated physiological medium. The high encapsulation efficiencies of MNPs and PTX were obtained, reaching 85 and 78 wt % for PTX-MNP-PLGA-Lys-Gal NPs, respectively. The tumor inhibitory rate of 78.8% reflected that the resulting NPs could be promising to treat cancer by specific binding and targeting release drug to tumor.

C-terminal amidation of an osteocalcin-derived peptide promotes hydroxyapatite crystallization.

Genesis of natural biocomposite-based materials, such as bone, cartilage, and teeth, involves interactions between organic and inorganic systems. Natural biopolymers, such as peptide motif sequences, can be used as a template to direct the nucleation and crystallization of hydroxyapatite (HA). In this study, a natural motif sequence consisting of 13 amino acids present in the first helix of osteocalcin was selected based on its calcium binding ability and used as substrate for nucleation of HA crystals. The acidic (acidic osteocalcin-derived peptide (OSC)) and amidic (amidic osteocalcin-derived peptide (OSN)) forms of this sequence were synthesized to investigate the effects of different C termini on the process of biomineralization. Electron microscopy analyses show the formation of plate-like HA crystals with random size and shape in the presence of OSN. In contrast, spherical amorphous calcium phosphate is formed in the presence of OSC. Circular dichroism experiments indicate conformational changes of amidic peptide to an open and regular structure as a consequence of interaction with calcium and phosphate. There is no conformational change detectable in OSC. It is concluded that HA crystal formation, which only occurred in OSN, is attributable to C-terminal amidation of a natural peptide derived from osteocalcin. It is also proposed that natural peptides with the ability to promote biomineralization have the potential to be utilized in hard tissue regeneration.

Peptide chain dynamics in light and heavy water: zooming in on internal friction.

Frictional effects due to the chain itself, rather than the solvent, may have a significant effect on protein dynamics. Experimentally, such "internal friction" has been investigated by studying folding or binding kinetics at varying solvent viscosity; however, the molecular origin of these effects is hard to pinpoint. We consider the kinetics of disordered glycine-serine and α-helix forming alanine peptides and a coarse-grained protein folding model in explicit-solvent molecular dynamics simulations. By varying the solvent mass over more than two orders of magnitude, we alter only the solvent viscosity and not the folding free energy. Folding dynamics at the near-vanishing solvent viscosities accessible by this approach suggests that solvent and internal friction effects are intrinsically entangled. This finding is rationalized by calculation of the polymer end-to-end distance dynamics from a Rouse model that includes internal friction. An analysis of the friction profile along different reaction coordinates, extracted from the simulation data, demonstrates that internal as well as solvent friction varies substantially along the folding pathways and furthermore suggests a connection between friction and the formation of hydrogen bonds upon folding.

The combined influence of surface modification, size distribution, and interaction time on the cytotoxicity of CdTe quantum dots in PANC-1 cells.

Mercaptopropionic acid (MPA) and cysteamine (Cys) capped CdTe quantum dots (QDs) were successfully prepared and used to investigate the combined influence of surface modification, size distribution, and interaction time on their cytotoxicity in human pancreatic carcinoma (PANC-1) cells. Results indicated that the smaller the size of MPA-CdTe QDs, the higher the cytotoxicity, which could be partly due to the difference of their distribution inside cells. Comparing with MPA-CdTe QDs, Cys-CdTe QDs had better cellular metabolizability and lower cytotoxicity. These QDs' cellular distribution and cytotoxicity were closely related to their interaction time with cells. Their cytotoxicity was found to be significantly enhanced with the increase of incubation time in medium. After QD treatments, the influence of recover time on the final cell viability was also dependent on the concentration and surface modification of QDs used in pretreatment. The combined influence of these factors discussed here might provide useful information for understanding and reducing the cytotoxicity of QDs in future biomedical applications.

Novel 5- and 6-subtituted benzothiazoles with improved physicochemical properties: potent S1P1 agonists with in vivo lymphocyte-depleting activity.

An SAR campaign designed to increase polarity in the 'tail' region of benzothiazole 1 resulted in two series of structurally novel 5-and 6-substituted S1P(1) agonists. Structural optimization for potency ultimately delivered carboxamide (+)-11f, which in addition to possessing improved physicochemical properties relative to starting benzothiazole 1, also displayed good S1P(3) selectivity and acceptable in vivo lymphocyte-depleting activity.

Physicochemical properties and inhibition effect on iron deficiency anemia of a novel polysaccharide-iron complex (LPPC).

Porphyran (P) was extracted from red algae Porphyra by boiling water. A novel polysaccharide-iron complex (LPPC) was prepared under the alkaline condition by adding a ferric chloride solution to the low molecular weight porphyran (LP) solution. Physicochemical properties and inhibition effect on iron deficiency anemia of this complex were studied. The content of iron(III) in the complex is 21.57% determined with iodometry. The results indicate that LPPC was product required. The complex can increase red blood cell count (RBC), hemoglobin (Hb), Serum iron (SI), spleen index, spleen mass and mass of mice with iron deficiency anemia (IDA). Although the structure and deeper mechanisms on hemolytic anemia of LPPC should be further studied, LPPC is hoped to be developed as a late-model iron supplement which has a synergism on anemia.

Advancing density functional theory to finite temperatures: methods and applications in steel design.

The performance of materials such as steels, their high strength and formability, is based on an impressive variety of competing mechanisms on the microscopic/atomic scale (e.g. dislocation gliding, solid solution hardening, mechanical twinning or structural phase transformations). Whereas many of the currently available concepts to describe these mechanisms are based on empirical and experimental data, it becomes more and more apparent that further improvement of materials needs to be based on a more fundamental level. Recent progress for methods based on density functional theory (DFT) now makes the exploration of chemical trends, the determination of parameters for phenomenological models and the identification of new routes for the optimization of steel properties feasible. A major challenge in applying these methods to a true materials design is, however, the inclusion of temperature-driven effects on the desired properties. Therefore, a large range of computational tools has been developed in order to improve the capability and accuracy of first-principles methods in determining free energies. These combine electronic, vibrational and magnetic effects as well as structural defects in an integrated approach. Based on these simulation tools, one is now able to successfully predict mechanical and thermodynamic properties of metals with a hitherto not achievable accuracy.

Cytochrome c biosensor--a model for gas sensing.

This work is about gas biosensing with a cytochrome c biosensor. Emphasis is put on the analysis of the sensing process and a mathematical model to make predictions about the biosensor response. Reliable predictions about biosensor responses can provide valuable information and facilitate biosensor development, particularly at an early development stage. The sensing process comprises several individual steps, such as phase partition equilibrium, intermediate reactions, mass-transport, and reaction kinetics, which take place in and between the gas and liquid phases. A quantitative description of each step was worked out and finally combined into a mathematical model. The applicability of the model was demonstrated for a particular example of methanethiol gas detection by a cytochrome c biosensor. The model allowed us to predict the optical readout response of the biosensor from tabulated data and data obtained in simple liquid phase experiments. The prediction was experimentally verified with a planar three-electrode electro-optical cytochrome c biosensor in contact with methanethiol gas in a gas tight spectroelectrochemical measurement cell.

Two-phase olive mill waste composting: community dynamics and functional role of the resident microbiota.

In this study, physico-chemical modifications and community dynamics and functional role of the resident microbiota during composting of humid husk from a two-phase extraction system (TPOMW) were investigated. High mineralization and humification of carbon, low loss of nitrogen and complete degradation of polyphenols led to the waste biotransformation into a high-quality compost. Viable cell counts and denaturing gradient gel electrophoresis (DGGE) profiling of the 16S rRNA genes showed that the thermophilic phase was characterized by the strongest variations of cell number, the highest biodiversity and the most variable community profiles. The isolation of tannin-degrading bacteria (e.g. Lysinibacillus fusiformis, Kocuria palustris, Tetrathiobacter kashmirensis and Rhodococcus rhodochrous) suggested a role of this enzymatic activity during the process. Taken together, the results indicated that the composting process, particularly the thermophilic phase, was characterized by a rapid succession of specialized bacterial populations with key roles in the organic matter biotransformation.

Membrane curvature sensing by amphipathic helices: a single liposome study using α-synuclein and annexin B12.

Preferential binding of proteins on curved membranes (membrane curvature sensing) is increasingly emerging as a general mechanism whereby cells may effect protein localization and trafficking. Here we use a novel single liposome fluorescence microscopy assay to examine a common sensing motif, the amphipathic helix (AH), and provide quantitative measures describing and distinguishing membrane binding and sensing behavior. By studying two AH-containing proteins, α-synuclein and annexin B12, as well as a range of AH peptide mutants, we reveal that both the hydrophobic and hydrophilic faces of the helix greatly influence binding and sensing. Although increased hydrophobic and electrostatic interactions with the membrane both lead to greater densities of bound protein, the former yields membrane curvature-sensitive binding, whereas the latter is not curvature-dependent. However, the relative contributions of both components determine the sensing of AHs. In contrast, charge density in the lipid membrane seems important primarily in attracting AHs to the membrane but does not significantly influence sensing. These observations were made possible by the ability of our assay to distinguish within our samples liposomes with and without bound protein as well as the density of bound protein. Our findings suggest that the description of membrane curvature-sensing requires consideration of several factors such as short and long range electrostatic interactions, hydrogen bonding, and the volume and structure of inserted hydrophobic residues.

Gas phase hydrogen/deuterium exchange of arginine and arginine dipeptides complexed with alkali metals.

The hydrogen/deuterium (H/D) exchange of protonated and alkali-metal cationized Arg-Gly and Gly-Arg peptides with D(2)O in the gas phase was studied using electrospray ionization quadropole ion trap mass spectrometry. The Arg-Gly and Gly-Arg alkali metal complexes exchange significantly more hydrogens than protonated Arg-Gly and Gly-Arg. We propose a mechanism where the peptide shifts between a zwitterionic salt bridge and nonzwitterionic charge solvated conformations. The increased rate of H/D exchange of the alkali metal complexes is attributed to the peptide metal complexes' small energy difference between the salt-bridge conformation and the nonzwitterionic charge-solvated conformation. Implications for the applicability of this mechanism to other zwitterionic systems are discussed.

Traceable multifunctional micellar nanocarriers for cancer-targeted co-delivery of MDR-1 siRNA and doxorubicin.

In this article we report on the development of polymeric micelles that can integrate multiple functions in one system, including the capability to accommodate a combination of therapeutic entities with different physicochemical properties (i.e., siRNA and doxorubicin; DOX), passive and active cancer targeting, cell membrane translocation, and pH-triggered drug release. A micellar system was constructed from degradable poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) block copolymers with functional groups on both blocks. The functional group on the PCL block was used to incorporate short polyamines for complexation with siRNA or to chemically conjugate DOX via a pH-sensitive hydrazone linkage. A virus mimetic shell was conferred by attaching two ligands, i.e., the integrin αvß3-specific ligand (RGD4C) for active cancer targeting and the cell-penetrating peptide TAT for membrane activity. This system was used to improve the efficacy of DOX in multidrug-resistant MDA-MB-435 human tumor models that overexpress P-glycoprotein (P-gp), by simultaneous intracellular delivery of DOX and siRNA against P-gp expression. The carrier was tagged with near-infrared fluorescent imaging probes to provide a means to follow the fate of the system in vivo upon intravenous administration. Dy677-labeled siRNA was also used to assess the in vivo stability of the siRNA carrier. This multifunctional polymeric micellar system was shown to be capable of DOX and siRNA delivery to their intracellular targets, leading to the inhibition of P-gp-mediated DOX resistance in vitro and targeting of αvß3-positive tumors in vivo.

Swelling-shrinking behavior of chemically cross-linked polypeptide gels from poly(α-L-lysine), poly(α-DL-lysine), poly(ɛ-L-lysine) and thermally prepared poly(lysine): effects of pH, temperature and additives in the solution.

We synthesized the glutaraldehyde cross-linked hydrogels using four kinds of poly(lysine)s (PLs) and measured the equilibrium swelling ratio (Q) as a function of pH. Also measured was the temperature change of Q at a fixed pH (11.6) in the absence and presence of additives (LiBr, methanol and urea) that affect the secondary structure of PLs. The swelling data were examined using a force balance approach in which the repulsive and attractive interactions among the cross-linked PL chains were considered based on the conformational properties of PLs in aqueous solutions. It was found that the formation of the helical segments in the cross-linked chain has little effect in the gel collapse, but their association acts as the attractive interaction causing the gel to shrink. The formation of the beta-sheet structure within the network also acts as the attractive interaction. These attractive interactions are mainly due to the hydrogen bonding, but hydrophobic interactions between the lysine side chains should be considered. In addition, in the swelling behavior of all the PL gels the polyampholyte nature appears due to electrostatic interactions of the basic groups with the C-terminal carboxyl group.

Development of nanocomposite based on hydroxyethylmethacrylate and functionalized fumed silica: mechanical, chemico-physical and biological characterization.

In this research work organic/inorganic nano composites were synthesized from poly-2-hydroxyethylmethacrylate and properly modified silica nanoparticles by in situ polymerization. In particular, fumed nanosilica was functionalized with methacryloylpropyltrimetoxy silane (MPTMS) in order to obtain a more homogeneous, reliable and mechanically performing nano composite. For comparison, nano composites with non functionalized silica were also prepared. Scanning electron microscopy was performed in order to visualize the effects of functionalization on the mode and state of dispersion. This analysis demonstrated that MPTMS grafted onto silica surface acts as an effective coupling agent and assures a good dispersion and distribution of nanoparticles as well as a strong nano particle/matrix interfacial adhesion. As a result of strong interactions occurring between phases, a pronounced increase of the glass transition temperature and mechanical parameters were recorded. Finally, these novel nano composites were seeded with murine fibroblast and human mesenchymal stem cells, and observed in time-lapse experiments proving an effective biological response.

Na-doped ß-tricalcium phosphate: physico-chemical and in vitro biological properties.

Synthetic calcium phosphate ceramics as ß-tricalcium phosphate (Ca(3)(PO(4))(2); ß-TCP) are currently successfully used in human bone surgery. The aim of this work was to evaluate the influence of the presence of sodium ion in ß-TCP on its mechanical and biological properties. Five Na-doped-ß-TCP [Ca(10.5-x/2)Na(x)(PO(4))(7), 0 ≤ x ≤ 1] microporous pellets were prepared via solid phase synthesis, and their physico-chemical data (lattice compacity, density, porosity, compressive strength, infrared spectra) denote an increase of the mechanical properties and a decrease of the solubility when the sodium content is raised. On the other hand, the in vitro study of MC3T3-E1 cell activity (morphology, MTS assay and ALP activity) shows that the incorporation of sodium does not modify the bioactivity of the ß-TCP. These results strongly suggest that Na-doped-ß-TCP appear to be good candidates for their use as bone substitutes.