2,003 research outputs found
Quasideterministic generation of maximally entangled states of two mesoscopic atomic ensembles by adiabatic quantum feedback
We introduce an efficient, quasideterministic scheme to generate maximally
entangled states of two atomic ensembles. The scheme is based on quantum
nondemolition measurements of total atomic populations and on adiabatic quantum
feedback conditioned by the measurements outputs. The high efficiency of the
scheme is tested and confirmed numerically for ideal photodetection as well as
in the presence of losses.Comment: 7 pages, 6 figures, title changed, revised version published on Phys.
Rev
Impact of ConcanavalinA affinity in the intracellular fate of Protein Corona on Glucosamine Au nanoparticles
Biological fate and toxicity of nanoparticles (NPs) are connected to the interaction between NPs and the protein corona (PC) spontaneously forming around NPs in biological matrixes. PC is a dynamic entity that confers biological identity to NPs. In this work, fluorescence cross-correlation spectroscopy (FCCS) is used to study the impact of specific interactions between the NP surface and proteins on the intracellular fate of PC. The stability of the PC formed around glucosamide-functionalized Au-NPs from ConcanavalinA (ConA) or Bovine Serum Albumin (BSA) is characterized by FCCS. The NPs show higher affinity for ConA and competitive assays show that ConA easily exchanges BSA. A549 cells are exposed to glucosamide-functionalized Au-NPs with preformed ConA and BSA PCs. Intracellularly the frequency of cross-correlation for Au NPs with ConA PC remains constant to a 70% value until 24 h while for BSA it decreases to a 15% during the same period. FCCS measurements in several locations in the cell point out a different level of aggregation for the NPs with either ConA or BSA PCs. Our results show that the affinity of NPs functionalized with a ligand with affinity for a specific protein in bulk is retained intracellularly influencing NP fate and translocation
Morning Blood Pressure Surge, Dipping, and Risk of Coronary Events in Elderly Treated Hypertensive Patients
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Volatiles and trace element contents in melt inclusions from the zoned Green Tuff ignimbrite (Pantelleria, Sicily): petrological inferences.
The island of Pantelleria is one of the best known localities of bimodal mafic-felsic magmatism (alkali basalt and trachyte-pantellerite). Among the felsic rocks, the coexistence in a single eruption of products of both trachyte and pantellerite compositions is limited to few occurrences, the Green Tuff (GT) ignimbrite being one of these. The GT is compositionally zoned from pantellerite (70.1 wt% SiO2, mol Na+K/Al = 1.86, 1871 ppm Zr) at the base to crystal-rich (\u3e30 vol%) comenditic trachyte (63.4 wt% SiO2, mol Na+K/Al = 1.10, 265 ppm Zr) at the top, although the pantellertic compositions dominate the erupted volume. We present here new data on melt inclusions (MIs) from the pantellerite portions of the GT eruption and, most importantly, from the trachyte member, which have not been studied in-situ by previous work focused on the GT. We document the first occurrence of trachytic melt inclusions in the late-erupted member, whose importance resides in the fact that trachytes were known mostly as crystal-rich lavas or ignimbrites, all variably affected by crystal accumulation. Besides the obvious inferences on the interplay between parental-derivative magmas, this evidence adds also some helpful elements in understanding zoning of silicic and peralkaline (i.e. low-viscosity) magma chambers. Trace elements compositions of MIs reveal that trachyte melts are of two types: (i) a low-Ba, directly descending from basaltic melts by 60-70 % of fractional crystallisation, and (ii) a high-Ba that might be affected by processes of feldspar dissolution and entrainment of the resulting small-scale melts in some MIs. MIs hosted in the deep-seated trachyte body are H2O-poor (≤ 1.2 wt %) with respect to the early erupted (and shallower) pantellerite magma (≤ 4.2 wt %), raising the possibility that either trachyte magma was H2O-undesaturated, or clinopyroxene hosted melt inclusions which suffered consistent H2O loss
Selective laser sintering of hydroxyapatite reinforced polyethylene composites for bioactive implants and tissue scaffold development
Selective laser sintering (SLS) has been investigated for the production of bioactive implants and tissue scaffolds using composites of high-density polyethylene (HDPE) reinforced with hydroxyapatite (HA) with the aim of achieving the rapid manufacturing of customized implants. Single-layer and multilayer block specimens made of HA-HDPE composites with 30 and 40 vol % HA were sintered successfully using a CO2 laser sintering system. Laser power and scanning speed had a significant effect on the sintering behaviour. The degree of particle fusion and porosity were influenced by the laser processing parameters, hence control can be attained by varying these parameters. Moreover, the SLS processing allowed exposure of HA particles on the surface of the composites and thereby should provide bioactive products. Pores existed in the SLS-fabricated composite parts and at certain processing parameters a significant fraction of the pores were within the optimal sizes for tissue regeneration. The results indicate that the SLS technique has the potential not only to fabricate HA-HDPE composite products but also to produce appropriate features for their application as bioactive implants and tissue scaffolds
Systemic Immune Responses in Alzheimer’s Disease: In Vitro Mononuclear Cell Activation and Cytokine Production
To investigate the systemic signs of immune-inflammatory responses in Alzheimer’s disease (AD), in the present study
we have analyzed blood lymphocyte subsets and the expression of activation markers on peripheral blood mononuclear cells
(PBMCs) fromADpatients and age-matched healthy controls (HC) activated in vitro by recombinant amyloid-β peptide (rAβ42).
Our study of AD lymphocyte subpopulations confirms the already described decrease of the absolute number and percentage of
B cells when compared to HC lymphocytes, whereas the other subsets are not significantly different in patients and controls.
We report the increased expression of the activation marker CD69 and of the chemokine receptors CCR2 and CCR5 on T cells
but no changes of CD25 after activation. B cells are also activated by rAβ42 as demonstrated by the enhanced expression of
CCR5. Moreover, rAβ42 induces an increased expression of the scavenger receptor CD36 on monocytes. Some activation
markers and chemokine receptors are overexpressed in unstimulated AD cells when compared to controls. This is evidence of
the pro-inflammatory status of AD. Stimulation by rAβ42 also induces the production of the pro-inflammatory cytokines IL-1β,
IL-6, IFN-γ, and TNF-α, and of the anti-inflammatory cytokines IL-10 and IL-1Ra. The chemokines RANTES, MIP-1β, and
eotaxin as well as some growth factors (GM-CSF, G-CSF) are also overproduced by AD-derived PBMC activated by rAβ42.
These results support the involvement of systemic immunity in AD patients. However, our study is an observational one so we
cannot draw a conclusion about its contribution to the pathophysiology of the disease
The effect of the protein corona on the interaction between nanoparticles and lipid bilayers
Hypothesis It is known that nanoparticles (NPs) in a biological fluid are immediately coated by a protein corona (PC), composed of a hard (strongly bounded) and a soft (loosely associated) layers, which represents the real nano-interface interacting with the cellular membrane in vivo. In this regard, supported lipid bilayers (SLB) have extensively been used as relevant model systems for elucidating the interaction between biomembranes and NPs. Herein we show how the presence of a PC on the NP surface changes the interaction between NPs and lipid bilayers with particular care on the effects induced by the NPs on the bilayer structure. Experiments In the present work we combined Quartz Crystal Microbalance with Dissipation Monitoring (QCM-D) and Neutron Reflectometry (NR) experimental techniques to elucidate how the NP-membrane interaction is modulated by the presence of proteins in the environment and their effect on the lipid bilayer. Findings Our study showed that the NP-membrane interaction is significantly affected by the presence of proteins and in particular we observed an important role of the soft corona in this phenomenon
Influence of surface coating on the intracellular behaviour of gold nanoparticles : a fluorescence correlation spectroscopy study
In the biomedical applications of nanoparticles (NPs), the proper choice of surface chemistry is a crucial aspect in their design. The nature of the coating can heavily impact the interaction of NPs with biomolecules, affect the state of aggregation, and ultimately determine their biological fate. As such, protein corona formation and the aggregation behaviour of gold NPs (Au NPs) are studied here. Au NPs are prepared with four distinct surface functionalisations, namely mercaptosuccinic acid (MSA), N-4-thiobutyroil glucosamine, HS-PEG5000 and HS-alkyl-PEG600. Corona formation, aggregation, and the intracellular behaviour of the Au NPs are then investigated by means of Fluorescence Correlation Spectroscopy (FCS) in cell culture media and in live cells. To evaluate the state of aggregation and the formation of a protein corona, the Au NPs are incubated in cell media and the diffusion coefficient is determined via FCS. The in vitro behaviour is compared with the level of aggregation of the NPs in cells. Diffusion times of the NPs are estimated at different positions in the cell after a one hour incubation period. It is found that the majority of MSA and glucose-Au NPs are present inside the cell as slowly diffusing species with diffusion times (\u3c4D) greater than 6000 \u3bcs (hydrodynamic diameter >250 nm). PEGylated Au NPs adsorb a small amount of protein and manifest low agglomeration both in media and in living cells. In particular, the HS-alkyl-PEG600 coating shows an excellent correlation between lower protein adsorption, 4-fold lower compared to the MSA coated NPs, and limited intracellular aggregation. In the case of single HS-alkyl-PEG600 coated NPs, it is found that typical intracellular \u3c4D values range from 500 to 1500 \u3bcs, indicating that these particles display reduced aggregation in the intracellular environment
An early developmental vertebrate model for nanomaterial safety:Bridging cell-based and mammalian toxicity assessment
Background. With the rise in production of nanoparticles for an ever-increasing number of applications, there is an urgent need to efficiently assess their potential toxicity. We propose a nanoparticle hazard assessment protocol that combines mammalian cytotoxicity data with embryonic vertebrate abnormality scoring to determine an overall toxicity index. Results. We observed that, after exposure to a range of nanoparticles, Xenopus phenotypic scoring showed a strong correlation with cell based in vitro assays. Magnetite-cored nanoparticles, negative for toxicity in vitro and Xenopus, were further confirmed as non-toxic in mice. Conclusion. The results highlight the potential of Xenopus embryo analysis as a fast screening approach for toxicity assessment of nanoparticles, which could be introduced for the routine testing of nanomaterials
LncRNA profiling in early-stage chronic lymphocytic leukemia identifies transcriptional fingerprints with relevance in clinical outcome
Long non-coding RNAs (lncRNAs) represent a novel class of functional RNA molecules with an important emerging role in cancer. To elucidate their potential pathogenetic role in chronic lymphocytic leukemia (CLL), a biologically and clinically heterogeneous neoplasia, we investigated lncRNAs expression in a prospective series of 217 early-stage Binet A CLL patients and 26 different subpopulations of normal B-cells, through a custom annotation pipeline of microarray data. Our study identified a 24-lncRNAsignature specifically deregulated in CLL compared with the normal B-cell counterpart. Importantly, this classifier was validated on an independent data set of CLL samples. Belonging to the lncRNA signature characterizing distinct molecular CLL subgroups, we identified lncRNAs recurrently associated with adverse prognostic markers, such as unmutated IGHV status, CD38 expression, 11q and 17p deletions, and NOTCH1 mutations. In addition, correlation analyses predicted a putative lncRNAs interplay with genes and miRNAs expression. Finally, we generated a 2-lncRNA independent risk model, based on lnc-IRF2-3 and lnc-KIAA1755-4 expression, able to distinguish three different prognostic groups in our series of early-stage patients. Overall, our study provides an important resource for future studies on the functions of lncRNAs in CLL, and contributes to the discovery of novel molecular markers with clinical relevance associated with the disease
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