When nanoparticles come into contact with biological media, they are covered by a biomolecular 'corona', which confers a new identity to the particles. In all the studies reported so far ...nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let multicomponent liposomes interact with fetal bovine serum (FBS) both statically and dynamically, i.e. in contact with circulating FBS (≈40 cm s(-1)). The structure and composition of the liposome-protein corona, as determined by dynamic light scattering, electrophoretic light scattering and liquid chromatography tandem mass spectrometry, were found to be dependent on the incubation protocol. Specifically, following dynamic exposure to FBS, multicomponent liposomes were less enriched in complement proteins and appreciably more enriched in apolipoproteins and acute phase proteins (e.g. alpha-1-antitrypsin and inter-alpha-trypsin inhibitor heavy chain H3) that are involved in relevant interactions between nanoparticles and living systems. Supported by our results, we speculate that efficient predictive modeling of nanoparticle behavior in vivo will require accurate knowledge of nanoparticle-specific protein fingerprints in circulating biological media.
Following exposure to biological milieus (e.g. after systemic administration), nanoparticles (NPs) get covered by an outer biomolecular corona (BC) that defines many of their biological outcomes, ...such as the elicited immune response, biodistribution, and targeting abilities. In spite of this, the role of BC in regulating the cellular uptake and the subcellular trafficking properties of NPs has remained elusive. Here, we tackle this issue by employing multicomponent (MC) lipid NPs, human plasma (HP) and HeLa cells as models for nanoformulations, biological fluids, and target cells, respectively. By conducting confocal fluorescence microscopy experiments and image correlation analyses, we quantitatively demonstrate that the BC promotes a neat switch of the cell entry mechanism and subsequent intracellular trafficking, from macropinocytosis to clathrin-dependent endocytosis. Nano-liquid chromatography tandem mass spectrometry identifies apolipoproteins as the most abundant components of the BC tested here. Interestingly, this class of proteins target the LDL receptors, which are overexpressed in clathrin-enriched membrane domains. Our results highlight the crucial role of BC as an intrinsic trigger of specific NP-cell interactions and biological responses and set the basis for a rational exploitation of the BC for targeted delivery.
A search for the CP-violating strong decays η → π+π− and η′(958) → π+π− has been performed using approximately 2.5 × 107 events of each of the decays D+ → π+π+π− and D s + → π + π + π − , recorded by ...the LHCb experiment. The data set corresponds to an integrated luminosity of 3.0 fb−1 of pp collision data recorded during LHC Run 1 and 0.3 fb−1 recorded in Run 2. No evidence is seen for D ( s ) + → π + η ( ′ ) with η (′) → π+π− and upper limits at 90% confidence level are set on the branching fractions, ℬ ( η → π + π − ) < 1.6 × 10 − 5 and ℬ ( η ′ → π + π − ) < 1.8 × 10 − 5 . The limit for the η decay is comparable with the existing one, while that for the η′ is a factor of three smaller than the previous limit.
The success of in vitro plant regeneration and the competence of genetic transformation greatly depends on the genotype of the species of interest. In previous work, we developed a method for the ...efficient Agrobacterium-mediated genetic transformation via organogenesis of V. vinifera cultivar Thompson Seedless, by using meristematic bulk (MB) as starting tissue. In this study, we applied this method for the regeneration and transformation of MBs obtained from the Italian cultivar Ciliegiolo and two of the commonly used Vitis rootstocks, 110 Richter and Kober 5BB, in comparison with Thompson Seedless. The A. tumefaciens strain EHA105, harbouring pK7WG2 binary vector, was used for the transformation trials, which allowed selection through the enhanced-green fluorescent protein (eGFP) and the neomycin phosphotransferase (nptII) gene. Putative transformed tissues and/or shoots were identified by either a screening based on the eGFP expression alone or its use in combination with kanamycin in the medium. MBs obtained from Thompson Seedless showed the highest regeneration and transformation cell competence, which subsequently allowed the recovery of stably transformed plants. Ciliegiolo, 110 Richter, and Kober 5BB, produced actively growing transgenic calli showing eGFP fluorescence, more consistently on selective media, but had no regenerative competence.
When liposomes are exposed to biological fluids, a dynamic coating of proteins immediately covers them. Similarly to the aura of plasma surrounding the Sun, plasma proteins are thought of as ...establishing an aura that surrounds each liposome, hence the phenomenon was dubbed ‘protein corona’. This natural functionalization includes proteins engaged from the blood that can interact with receptors (over)expressed on the plasma membrane of target cells, thus targeting the liposomes to their final destination. Exploiting the liposome–protein corona for targeting has the potential to revolutionize the treatment of many disorders and requires a deep understanding of the factors shaping the corona. Following incubation with human plasma (HP), here we manipulated this corona by using six liposomal formulations with systematic changes in lipid composition. The lipids we employed are among the most frequently used lipid species for drug and gene delivery applications in vitro and in vivo . The six liposome–protein coronas were thoroughly characterized by synchrotron small angle X-ray scattering, dynamic light scattering, zeta-potential and nanoliquid-chromatography tandem mass spectrometry experiments. We identified general principles shaping the liposome–protein corona and established clear-cut relationships between lipid species and classes of plasma proteins. This knowledge sets the basis for a rational manipulation of the protein corona for targeted drug delivery by liposome design.
The Advanced Fuels Campaign Fission Accelerated Steady-state Test (FAST) at Idaho National Laboratory (INL) completed its first irradiation cycle within the Advanced Test Reactor (ATR). The test ...focused on the irradiation of alloy fuel forms for use in sodium fast reactors. The first cycle of FAST testing was completed and four rodlets were removed for the initial post irradiation examination (PIE). The rodlet design and irradiation conditions were evaluated using Monte Carlo N-Particle (MCNP) for as-run power history and COMSOL for temperature analysis. These rodlets include a set of low burnups (∼2.5 % fissions per initial metal atoms %FIMA), control rodlets, and a helium-bonded annular rodlet (4.7 %FIMA). Non-destructive PIE has been completed and includes visual inspection, neutron radiography and gamma scanning of the FAST capsules and rodlets. Radiography confirmed the integrity of the experiments, revealed that the annulus in the annular fuel was filled at a modest burnup (4.7 %FIMA), and indicated potential slumping of the cooler rodlets at lower burnup. Precision gamma scanning indicated mostly usual fission product behavior, except for cesium in the He-bonded annular fuel. Future destructive PIE will be necessary to fully interpret the effects of accelerated irradiation on U-Zr metallic fuel behavior.
•Post-irradiation examination of nonfertile metallic fuels (no uranium) tests are presented here for a series of compositions with and without minor actinides.•Precision gamma scanning and fission ...gas release results are similar to other historical metal fuel experiments in fast reactors.
This work was part of a program begun in 2001 to develop advanced nuclear fuels, originally as carriers for plutonium and minor actinides (neptunium, curium, and americium) taken from spent commercial light-water reactors (LWR) so that the plutonium and minor actinides could be ‘burned’ or transmuted in an accelerator or a fast nuclear reactor. A central part of these experiment programs has been the development of advanced fast reactor fuels, because a fast reactor was considered the most efficient vehicle to transmute the actinide waste products, and metallic fuels is a central focus of these tests. An experiment design was developed in which a thermal test reactor, the Advanced Test Reactor (ATR), was used to test small fuel pin prototypes, by creating areas in the core shielded by cadmium filters to produce a largely epithermal and fast neutron spectrum environment in which the pins could be irradiated. The results of non-fertile metallic fuel (no uranium) tests are presented here.
Pu-Am-Np-Zr fuels were irradiated to fission densities up to 33 × 1020 fission/cm3 and Pu-239 depletions of up to 39%. The depletions were created by roughly 2/3 by fission and 1/3 by transmutation neutron capture. Up to five fuel ‘rodlets’ were irradiated in three sealed capsules stacked axially in the core, and the peak cladding temperatures ranged from 300°C to 500°C, depending on axial location as those near the core centerline are operating hotter and to higher fission densities. Several post-irradiation examinations (precision gamma scanning and fission gas release) were similar to other historical metal fuel experiments in fast reactors. However, optical metallography indicated that two of the rodlets had breached. The exact reasons are unclear. Due to the design of this irradiation experiment a rodlet breach could have increased the temperature in others in the same capsule by contaminating the thermal gap helium with heavier and less conductive fission product gases. Some of those rodlets showed high amounts of fuel/cladding chemical interaction (FCCI).
With the increasing interest in sodium fast reactor technology, as seen by applications to the U.S. Nuclear Regulatory Commission for the OKLO Aurora plant, fuel testing for the TerraPower Traveling ...Wave Reactor, and the impending construction and startup of the versatile test reactor (VTR), a modernized, accelerated approach to fuel qualification is needed. To guide this effort, a Phenomena Identification Ranking Table-styled analysis was performed for a U-Pu-Zr sodium-free annular fuel system. This analysis evaluated a series of fuel design properties and parameters against their contributions to key fuel performance phenomena. The resulting priority parameters were then reviewed against existing modeling and experimental capabilities to support investigation of the highest-priority parameters. A pathway for qualification was then established using high-throughput, high-volume experiments from MiniFuel and FAST in parallel with advanced physics-based model development. This effort outlines how the first stages of qualification can be reduced from the typical 20+-year development cycle to 5 to 7 years by deploying accelerated irradiation testing platforms. As with any accelerated test, these methods are prototypic in some aspects and less so in others; however, by coupling with advanced fuel performance modeling and simulation capabilities, the larger space of irradiation parameters and material response provided offers advantages for the validation of physics-based models supporting the deployment of novel fuel designs. As a test case, this paper utilizes a proposed Mark II fuel system for the upcoming VTR. Thus, an accelerated qualification method can be tested for the development of MARK II driver fuel so that by the time of VTR startup, lead test assemblies for a Mark II fuel can be initiated.
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•Melting of the full UO2–ThO2 system was studied by laser heating.•A minimum melting point was found around 5 mol% ThO2 and T = 3098 K.•Ideal solution behaviour near melting was ...observed for compositions richer in ThO2.•These compounds were also studied by Raman spectroscopy before and after melting.
The high-temperature phase diagram of the UO2–ThO2 system has been experimentally revisited in the present study for the first time since 1970, using a laser heating approach combined with fast pyrometry in a thermal arrest method. The melting/solidification temperature, which is of fundamental information for a reactor design was studied here. It was found that low addition of ThO2 to UO2 would result in a slight decrease of the solidification temperature. A minimum was found at 3098 K around a composition of 5 mol% ThO2. The solid/liquid transition temperature was then observed to increase again with increasing ThO2 fraction. The literature value of pure ThO2 (around 3630 K) was well reproduced here. Important experimental difficulties, stemming from the high temperatures reached during the measurements, as well as a complete investigation with electron microscopy, Raman spectroscopy and powder X-ray diffraction, are extensively discussed. These results show the importance of the high-temperature oxygen chemistry in this actinide oxide compound.
Purpose: Extracellular Vesicles (EVs) are a heterogeneous group of cell-derived membranous nanoparticles involved in several physiopathological processes. EVs play a crucial role in the definition of ...the extracellular microenvironment through the transfer of their cargo. Psoriasis is a prototypical chronic inflammatory disease characterized by several secreted mediators, among which antimicrobial peptides (AMPs) are considered pivotal in the development of the psoriatic inflammatory microenvironment. The role of EVs in the pathogenesis of psoriasis has not been elucidated yet, even if emerging evidence demonstrated that interleukin-17A (IL-17A), the psoriasis-related principal cytokine, modifies EVs release and cargo content. The aim of this work was to analyze whether, besides IL-17A, other psoriasis-related cytokines (ie, IFN-gamma, TNF-alpha, IL-22 and IL-23) could affect EVs release and their AMPs mRNAs cargo as well as to analyze the potential biological effect due to EVs internalization by different acceptor cells. Methods: Nanoparticle tracking analysis (NTA) was performed on supernatants of HaCaT cells stimulated with IL-17A, IFN-gamma, TNF-alpha, IL-22 or IL-23 to enumerate EVs. Real-Time RT-PCR was used for gene expression analysis in cells and EVs. Confocal microscopy and Flow cytometry were used to, respectively, study Netosis and EVs internalization. Results: IL-17A and IFN-gamma increased EVs release by HaCaT cells. All the tested cytokines modulated AMPs mRNA expression in parental cells and in their respective EVs. S100A12 and hBD2 mRNAs were upregulated following IL-17A and IL-22 treatments. Interestingly, EVs derived from cytokine treated HaCaT cells induced Netosis in freshly isolated neutrophils. Upregulation of S100A12 and hBD2 mRNA was also detectable in acceptor cells incubated with EVs derived from cells treated with psoriasis-related cytokines. Conclusion: The obtained results highlighted the role of EVs in the composition of psoriasis-associated secretome and microenvironment also suggesting the EV involvement in the spreading of the disease mediators and in the possible associated comorbidities. Keywords: extracellular vesicles, antimicrobial peptides, cytokines, keratinocytes, pathogenesis of psoriasis, comorbidities
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