2,417 research outputs found
The International Society for Extracellular Vesicles launches the first massive open online course on extracellular vesicles
The International Society for Extracellular Vesicles (ISEV) has organised its first educational online course for students and beginners in the field of extracellular vesicles (EVs). This course, "Basics of Extracellular Vesicles,'' uses recorded lectures from experts in the field and will be open for an unlimited number of participants. The course is divided into 5 modules and can be accessed at www.coursera.org/learn/extracellular-vesicles. The first module is an introduction to the field covering the nomenclature and history of EVs. Module 2 focuses on the biogenesis and uptake mechanisms of EVs, as well as their RNA, protein and lipid cargo. Module 3 covers the collection and processing of cell culture media and body fluids such as blood, breast milk, cerebrospinal fluid and urine prior to isolation of EVs. Modules 4 and 5 present different isolation methods and characterisation techniques utilised in the EV field. Here, differential ultracentrifugation, size-exclusion chromatography, density gradient centrifugation, kit-based precipitation, electron microscopy, cryo-electron microscopy, flow cytometry, atomic-force microscopy and nanoparticle-tracking analysis are covered. This first massive open online course (MOOC) on EVs was launched on 15 August 2016 at the platform "Coursera'' and is free of charge.11Ysciescopu
Photoacoustic Reconstruction Using Sparsity in Curvelet Frame: Image Versus Data Domain
Curvelet frame is of special significance for photoacoustic tomography (PAT) due to its sparsifying and microlocalisation properties. We derive a one-to-one map between wavefront directions in image and data spaces in PAT which suggests near equivalence between the recovery of the initial pressure and PAT data from compressed/subsampled measurements when assuming sparsity in Curvelet frame. As the latter is computationally more tractable, investigation to which extent this equivalence holds conducted in this paper is of immediate practical significance. To this end we formulate and compare DR , a two step approach based on the recovery of the complete volume of the photoacoustic data from the subsampled data followed by the acoustic inversion, and p0R , a one step approach where the photoacoustic image (the initial pressure, p0 ) is directly recovered from the subsampled data. Effective representation of the photoacoustic data requires basis defined on the range of the photoacoustic forward operator. To this end we propose a novel wedge-restriction of Curvelet transform which enables us to construct such basis. Both recovery problems are formulated in a variational framework. As the Curvelet frame is heavily overdetermined, we use reweighted â1 norm penalties to enhance the sparsity of the solution. The data reconstruction problem DR is a standard compressed sensing recovery problem, which we solve using an ADMM-type algorithm, SALSA. Subsequently, the initial pressure is recovered using time reversal as implemented in the k-Wave Toolbox. The p0 reconstruction problem, p0R , aims to recover the photoacoustic image directly via FISTA, or ADMM when in addition including a non-negativity constraint. We compare and discuss the relative merits of the two approaches and illustrate them on 2D simulated and 3D real data in a fair and rigorous manner
Strong Ultraviolet Pulse From a Newborn Type Ia Supernova
Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs.
Although they are used empirically to measure cosmological distances, the
nature of their progenitors remains mysterious, One of the leading progenitor
models, called the single degenerate channel, hypothesizes that a white dwarf
accretes matter from a companion star and the resulting increase in its central
pressure and temperature ignites thermonuclear explosion. Here we report
observations of strong but declining ultraviolet emission from a Type Ia
supernova within four days of its explosion. This emission is consistent with
theoretical expectations of collision between material ejected by the supernova
and a companion star, and therefore provides evidence that some Type Ia
supernovae arise from the single degenerate channel.Comment: Accepted for publication on the 21 May 2015 issue of Natur
Nanovesicles from Malassezia sympodialis and Host Exosomes Induce Cytokine Responses â Novel Mechanisms for Host-Microbe Interactions in Atopic Eczema
BACKGROUND: Intercellular communication can occur via the release of membrane vesicles. Exosomes are nanovesicles released from the endosomal compartment of cells. Depending on their cell of origin and their cargo they can exert different immunoregulatory functions. Recently, fungi were found to produce extracellular vesicles that can influence host-microbe interactions. The yeast Malassezia sympodialis which belongs to our normal cutaneous microbial flora elicits specific IgE- and T-cell reactivity in approximately 50% of adult patients with atopic eczema (AE). Whether exosomes or other vesicles contribute to the inflammation has not yet been investigated. OBJECTIVE: To investigate if M. sympodialis can release nanovesicles and whether they or endogenous exosomes can activate PBMC from AE patients sensitized to M. sympodialis. METHODS: Extracellular nanovesicles isolated from M. sympodialis, co-cultures of M. sympodialis and dendritic cells, and from plasma of patients with AE and healthy controls (HC) were characterised using flow cytometry, sucrose gradient centrifugation, Western blot and electron microscopy. Their ability to stimulate IL-4 and TNF-alpha responses in autologous CD14, CD34 depleted PBMC was determined using ELISPOT and ELISA, respectively. RESULTS: We show for the first time that M. sympodialis releases extracellular vesicles carrying allergen. These vesicles can induce IL-4 and TNF-α responses with a significantly higher IL-4 production in patients compared to HC. Exosomes from dendritic cell and M. sympodialis co-cultures induced IL-4 and TNF-α responses in autologous CD14, CD34 depleted PBMC of AE patients and HC while plasma exosomes induced TNF-α but not IL-4 in undepleted PBMC. CONCLUSIONS: Extracellular vesicles from M. sympodialis, dendritic cells and plasma can contribute to cytokine responses in CD14, CD34 depleted and undepleted PBMC of AE patients and HC. These novel observations have implications for understanding host-microbe interactions in the pathogenesis of AE
Feasibility of an in situ measurement device for bubble size and distribution
The feasibility of in situ measurement device for bubble size and distribution was explored. A novel in situ probe measurement system, the EnviroCamâą, was developed. Where possible, this probe incorporated strengths, and minimized weaknesses of historical and currently available real-time measurement methods for bubbles. The system was based on a digital, high-speed, high resolution, modular camera system, attached to a stainless steel shroud, compatible with standard Ingold ports on fermenters. Still frames and/or video were produced, capturing bubbles passing through the notch of the shroud. An LED light source was integral with the shroud. Bubbles were analyzed using customized commercially available image analysis software and standard statistical methods. Using this system, bubble sizes were measured as a function of various operating parameters (e.g., agitation rate, aeration rate) and as a function of media properties (e.g., viscosity, antifoam, cottonseed flour, and microbial/animal cell broths) to demonstrate system performance and its limitations. For selected conditions, mean bubble size changes qualitatively compared favorably with published relationships. Current instrument measurement capabilities were limited primarily to clear solutions that did not contain large numbers of overlapping bubbles
Identification of Giardia lamblia DHHC Proteins and the Role of Protein S-palmitoylation in the Encystation Process
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.Fil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra. Universidad Nacional de CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra; ArgentinaFil: Zamponi, Nahuel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra. Universidad Nacional de CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra; ArgentinaFil: Vranych, Cecilia VerĂłnica. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra. Universidad Nacional de CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra. Universidad Nacional de CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra. Universidad Nacional de CĂłrdoba. Instituto de InvestigaciĂłn MĂ©dica Mercedes y MartĂn Ferreyra; Argentin
Evidence for an excess of B -> D(*) Tau Nu decays
Based on the full BaBar data sample, we report improved measurements of the
ratios R(D(*)) = B(B -> D(*) Tau Nu)/B(B -> D(*) l Nu), where l is either e or
mu. These ratios are sensitive to new physics contributions in the form of a
charged Higgs boson. We measure R(D) = 0.440 +- 0.058 +- 0.042 and R(D*) =
0.332 +- 0.024 +- 0.018, which exceed the Standard Model expectations by 2.0
sigma and 2.7 sigma, respectively. Taken together, our results disagree with
these expectations at the 3.4 sigma level. This excess cannot be explained by a
charged Higgs boson in the type II two-Higgs-doublet model. We also report the
observation of the decay B -> D Tau Nu, with a significance of 6.8 sigma.Comment: Expanded section on systematics, text corrections, improved the
format of Figure 2 and included the effect of the change of the Tau
polarization due to the charged Higg
Search for the decay modes D^0 â e^+e^-, D^0 â ÎŒ^+ÎŒ^-, and D^0 â e^±Όâ
We present searches for the rare decay modes D^0âe^+e^-, D^0âÎŒ^+ÎŒ^-, and D^0âe^±Ό^â in continuum e^+e^-âcc events recorded by the BABAR detector in a data sample that corresponds to an integrated luminosity of 468ââfb^(-1). These decays are highly GlashowâIliopoulosâMaiani suppressed but may be enhanced in several extensions of the standard model. Our observed event yields are consistent with the expected backgrounds. An excess is seen in the D^0âÎŒ^+ÎŒ^- channel, although the observed yield is consistent with an upward background fluctuation at the 5% level. Using the FeldmanâCousins method, we set the following 90% confidence level intervals on the branching fractions: B(D^0âe^+e^-)<1.7Ă10^(-7), B(D^0âÎŒ^+ÎŒ^-) within [0.6,8.1]Ă10^(-7), and B(D^0âe^±Ό^â)<3.3Ă10^(-7)
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