A nanoparticle comprising a micelle formed by an amphiphilic block copolymer and encapsulating a gadolinium complex

Publication number: WO2011/113616The present invention relates to a nanoparticle comprising a micelle formed by an amphophilic block-copolymer and an agent encapsulated within said micelle. The present invention also relates to a composition comprising such nanoparticle and to the use of such nanoparticle and/or of such composition. More particularly, in one embodiment, the invention describes a new class of polymeric nanoparticles as smart Tl contrast agent for MR imaging for breast cancer early detection. These nanoparticles contrast agents have the capability to remain switched off during circulation and then switch on their imaging capacity upon arrival at the target sites (tissue of interest). These smart nanoparticles contrast agent are self-assembled from pH sensitive amphiphilic polymer, loaded with Gadolinium (Gd3+) complex based Tl agent and then fitted with targeting biomolecules such as antibody, small molecules or DNA to increase its specificity toward the target of interest

TaqMan real-time PCR assay for relative quantitation of white spot syndrome virus infection in Penaeus monodon Fabricius exposed to ammonia.

White spot disease is caused by a highly virulent pathogen, the white spot syndrome virus (WSSV). The disease is usually triggered by changes in environmental parameters causing severe losses to the shrimp industry. This study was undertaken to quantify the relative WSSV load in shrimp exposed to ammonia, using a TaqMan-based real-time PCR, and their subsequent susceptibility to WSSV. Shrimp were exposed to different levels of total ammonia nitrogen (TAN) (8.1, 3.8 and 1.1 mg L−1) for 10 days and challenged with WSSV by feeding WSSV-positive shrimp. WSSV was detected simultaneously in haemolymph, gills and pereopods at four hours post-infection. The TaqMan real-time PCR assay showed a highly dynamic detection limit that spanned over 6 log10 concentrations of DNA and high reproducibility (standard deviation 0.33–1.42) and small correlation of variability (CV) (1.89–3.85%). Shrimp exposed to ammonia had significantly higher (P < 0.01) WSSV load compared to the positive control, which was not exposed to ammonia. Shrimp exposed to 8.1 mg L−1 of TAN had the highest (P < 0.01) WSSV load in all three organs in comparison with those exposed to 3.8 and 1.1 mg L−1 of TAN. However, haemolymph had significantly higher (P < 0.01) viral load compared to the gills and pereopods. Results showed that shrimp exposed to ammonia levels as low as 1.1 mg L−1 (TAN) had increased susceptibility to WSSV

Biological activities and chemical composition of methanolic extracts of selected Autochthonous microalgae strains from the Red Sea

Four lipid-rich microalgal species from the Red Sea belonging to three different genera (Nannochloris, Picochlorum and Desmochloris), previously isolated as novel biodiesel feedstocks, were bioprospected for high-value, bioactive molecules. Methanol extracts were thus prepared from freeze-dried biomass and screened for different biological activities. Nannochloris sp. SBL1 and Desmochloris sp. SBL3 had the highest radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl, and the best copper and iron chelating activities. All species had potent butyrylcholinesterase inhibitory activity (>50%) and mildly inhibited tyrosinase. Picochlorum sp. SBL2 and Nannochloris sp. SBL4 extracts significantly reduced the viability of tumoral (HepG2 and HeLa) cells with lower toxicity against the non-tumoral murine stromal (S17) cells. Nannochloris sp. SBL1 significantly reduced the viability of Leishmania infantum down to 62% (250 mu g/mL). Picochlorum sp. SBL2 had the highest total phenolic content, the major phenolic compounds identified being salicylic, coumaric and gallic acids. Neoxanthin, violaxanthin, zeaxanthin, lutein and -carotene were identified in the extracts of all strains, while canthaxanthin was only identified in Picochlorum sp. SBL2. Taken together, these results strongly suggest that the microalgae included in this work could be used as sources of added-value products that could be used to upgrade the final biomass value.National Science, Technology and Innovation Program of King Abdulaziz Medical City for Science and Technology, Riyadh, Saudi Arabia [NPST, 11-ENE 1719-02]; Foundation for Science and Technology (FCT), Portugal [SFRH/BD/78062/2011]; FCT [IF/00049/2012, SFRH/BPD/86071/2012, Pest-OE/QUI/UI0612/2013]info:eu-repo/semantics/publishedVersio

Correlation of numerical and experimental analysis for dynamic behaviour of a 3 blade propeller structure

In pursuance of deciding the dependability of data gathered by testing a finite element modal in the software version, experimental data is frequently used for validation. On account of finite element analysis, it can sometimes be considered as inaccurate particularly when applied to the complex structure, for example, a propeller blade. This is because of challenges that may happen in the modelling of joints, boundary conditions, and damping of the structure. In this research, a procedure of correlation and validation of the model-based test plan with modal testing results was conducted. Modal properties (normal frequencies, mode shapes, and damping ratio) of a propeller blade structure were resolved by using both test experimental modal analysis (EMA) and finite element analysis (FEA). Correlation of both sets of data was performed for validation. It created the impression that there was a noticeable estimation of error between those two sets of data. Small discrepancies of percentage error of obtained natural frequency for FEA and EMA makes both of the methods can be applied to determine the dynamic characteristic of the propeller structure

Removal of Crystal Violet and Hexavalent Chromium using TiO2-Bentonite under Sunlight: Effect of TiO2 Content

The main objective of this study was to investigate the correlation between TiO2 content in photoactive bentonite (B-TiO2) and the pathway by which crystal violet (CV) and hexavalent chromium (Cr (VI)) are removed from water under sunlight. B-TiO2 samples were prepared by impregnation with TiCl4 with different weight ratios (g/g) (namely, 5, 10, 20 and 30%). Materials were characterized using different techniques, among which: SEM, FT-IR, XRD, HRTEM, EDX and Zeta potential measurements. Results show that, only the anatase TiO2 polymorph was formed in the bentonite and the porosity of materials decreases with the increase of TiO2 content. Furthermore, zeta potential measurements indicate that, when TiO2 content increases, the negative charge of materials decreases. On the other hand, experimental results show that these materials combine both adsorption and photocatalytic reactions to remove CV molecules from water. As the TiO2 content increases, the adsorption capacity decreases, while the photocatalytic activity is more important. In the case of Cr (VI) species, all samples show a few adsorption because of the repulsion effect between these species and the negative charge of the bentonite. Therefore, under sunlight, the Cr (VI) removal occurred mainly by the photoreduction reaction that is more efficient when the TiO2 content increases

Normal mode finite element analysis of aerofoil wing structure with different materials

There are a lot of study regarding on the aircraft components. One of the critical components for an aircraft would be the wings. The wing structure of an aircraft is one of the complex structures of a designed aircraft. This paper is about identifying the modal properties which are the mode shape and the corresponding natural frequencies of the aircraft wing structure. The modal properties of the wing structure would be compared for two different materials applied towards the wing structures which are the aluminium alloy AA-7075-T6 and AA-2024-T3 which currently being widely used by the aircrafts. The study for this aircraft wing structure would be using the approach of finite element analysis (FEA) method. The 3D model is design by using SolidWorks. The modal properties are identified with the help of MSC PATRAN and MSC NASTRAN. The results obtained for both materials for 10 mode shapes are compared and it could be observed that AA-7075-T6 are much lower compared to AA-2024-T3. Hence, from the result, AA-7075-T6 is more suitable to be used for the wing structures

Self-assembled polymeric nanoparticles as new, smart contrast agents for cancer early detection using magnetic resonance imaging

Early cancer detection is a major factor in the reduction of mortality and cancer management cost. Here we developed a smart and targeted micelle-based contrast agent for magnetic resonance imaging (MRI), able to turn on its imaging capability in the presence of acidic cancer tissues. This smart contrast agent consists of pH-sensitive polymeric micelles formed by self-assembly of a diblock copolymer (poly(ethyleneglycol-b-trimethylsilyl methacrylate)), loaded with a gadolinium hydrophobic complex ((t)BuBipyGd) and exploits the acidic pH in cancer tissues. In vitro MRI experiments showed that (t)BuBipyGd-loaded micelles were pH-sensitive, as they turned on their imaging capability only in an acidic microenvironment. The micelle-targeting ability toward cancer cells was enhanced by conjugation with an antibody against the MUC1 protein. The ability of our antibody-decorated micelles to be switched on in acidic microenvironments and to target cancer cells expressing specific antigens, together with its high Gd(III) content and its small size (35-40 nm) reveals their potential use for early cancer detection by MRI

Toward an automated method for optical coherence tomography characterization

With the increasing use of optical coherence tomography (OCT) in biomedical applications, robust yet simple methods for calibrating and benchmarking a system are needed. We present here a procedure based on a calibration object complemented with an algorithm that analyzes three-dimensional OCT datasets to retrieve key characteristics of an OCT system. The calibration object combines state-of-the-art tissue phantom material with a diamond-turned aluminum multisegment mirror. This method is capable of determining rapidly volumetric field-of-view, axial resolution, and image curvature. Moreover, as the phantom material mimics biological tissue, the system's signal and noise levels can be evaluated in conditions close to biological experiments. We believe this method could improve OCT quantitative data analysis and help OCT data comparison for longitudinal or multicenter studies

Precipitation with polyethylene glycol followed by washing and pelleting by ultracentrifugation enriches extracellular vesicles from tissue culture supernatants in small and large scales

Extracellular vesicles (EVs) provide a complex means of intercellular signalling between cells at local and distant sites, both within and between different organs. According to their cell-type specific signatures, EVs can function as a novel class of biomarkers for a variety of diseases, and can be used as drug-delivery vehicles. Furthermore, EVs from certain cell types exert beneficial effects in regenerative medicine and for immune modulation. Several techniques are available to harvest EVs from various body fluids or cell culture supernatants. Classically, differential centrifugation, density gradient centrifugation, size-exclusion chromatography and immunocapturing-based methods are used to harvest EVs from EV-containing liquids. Owing to limitations in the scalability of any of these methods, we designed and optimised a polyethylene glycol (PEG)based precipitation method to enrich EVs from cell culture supernatants. We demonstrate the reproducibility and scalability of this method and compared its efficacy with more classical EV-harvesting methods. We show that washing of the PEG pellet and the re-precipitation by ultracentrifugation remove a huge proportion of PEG co-precipitated molecules such as bovine serum albumine (BSA). However, supported by the results of the size exclusion chromatography, which revealed a higher purity in terms of particles per milligram protein of the obtained EV samples, PEG-prepared EV samples most likely still contain a certain percentage of other non-EV associated molecules. Since PEG-enriched EVs revealed the same therapeutic activity in an ischemic stroke model than corresponding cells, it is unlikely that such co-purified molecules negatively affect the functional properties of obtained EV samples. In summary, maybe not being the purification method of choice if molecular profiling of pure EV samples is intended, the optimised PEG protocol is a scalable and reproducible method, which can easily be adopted by laboratories equipped with an ultracentrifuge to enrich for functional active EVs