Search

Raman micro-spectroscopy is becoming very popular in the field of radiobiology and radiation oncology for its ability to assess the cellular damage at the molecular level. It can be used to monitor the minimum doses required to lethally damage tumor cells, as well as to reduce the risk of excess dose being delivered to healthy surrounding cells. These results can be achieved also thanks to the development of specific data analysis methods enabling the extraction of information embedded in the Raman spectra of complex samples, such as human cells. Among different data analysis procedures, multivariate analysis has been proven to be particularly effective. The principal component analysis (PCA) method has been largely used for analyzing Raman spectra from cells and tissues. In some cases, the PCA can be performed on selected wavenumber ranges of Raman spectra to get information embedded in those specific ranges (interval-PCA). In the present work, the application of these methods to the analysis of Raman spectra from single SH-SY5Y neuroblastoma cells following the exposure to graded doses of X-rays is reported and specific details from X-ray effects on nucleus and cytoplasm regions are obtained. In addition, the biochemical changes occurring in these cells are also discussed by using an alternative approach, namely the analysis of difference spectra, obtained by subtracting the cytoplasm-related spectrum from the corresponding one detected at the nucleus. It's worth to note that multivariate analysis has allowed us to unravel the subtle modifications, due to X-ray irradiation, of Raman features related to specific components. These results pave the way to develop proper data analysis methods allowing to manage, on one hand, the complexity of the Raman spectra of cells and tissues and, on the other hand, the high number of spectra needed to consider the intrinsic variability of biological samples.

Aims: We present the X-ray imaging and spectral analysis of the diffuse emission around the radio galaxy J1140-2629 (the Spiderweb galaxy) at z = 2.16 and of its nuclear emission, based on a deep (700 ks) Chandra observation. Methods: We obtained a robust characterization of the unresolved nuclear emission, and carefully computed the contamination in the surrounding regions due to the wings of the instrument point spread function. Then, we quantified the extended emission within a radius of 12 arcsec. We used the Jansky Very Large Array radio image to identify the regions overlapping the jets, and performed X-ray spectral analysis separately in the jet regions and in the complementary area. Results: We find that the Spiderweb galaxy hosts a mildly absorbed quasar, showing a modest yet significant spectral and flux variability on a timescale of ∼1 year (observed frame). We find that the emission in the jet regions is well described by a power law with a spectral index of Γ ∼ 2 − 2.5, and it is consistent with inverse-Compton upscattering of the cosmic microwave background photons by the relativistic electrons. We also find a roughly symmetric, diffuse emission within a radius of ∼100 kpc centered on the Spiderweb galaxy. This emission, which is not associated with the jets, is significantly softer and consistent with thermal bremsstrahlung from a hot intracluster medium (ICM) with a temperature of kT = 2.0−0.4+0.7 keV, and a metallicity of Z < 1.6 Z⊙ at 1σ c.l. The average electron density within 100 kpc is ne = (1.51 ± 0.24 ± 0.14) × 10−2 cm−3, corresponding to an upper limit for the total ICM mass of ≤(1.76 ± 0.30 ± 0.17) × 1012 M⊙ (where error bars are 1σ statistical and systematic, respectively). The rest-frame luminosity L0.5 − 10 keV = (2.0 ± 0.5) × 1044 erg s−1 is about a factor of 2 higher than the extrapolated L − T relation for massive clusters, but still consistent within the scatter. If we apply hydrostatic equilibrium to the ICM, we measure a total gravitational mass M(

The mechanism of T cell antigen receptor (TCR-CD3) signaling remains elusive. Here, we identify mutations in the transmembrane region of TCRβ or CD3ζ that augment peptide T cell antigen receptor (pMHC)-induced signaling not explicable by enhanced ligand binding, lateral diffusion, clustering, or co-receptor function. Using a biochemical assay and molecular dynamics simulation, we demonstrate that the gain-of-function mutations loosen the interaction between TCRαβ and CD3ζ. Similar to the activating mutations, pMHC binding reduces TCRαβ cohesion with CD3ζ. This event occurs prior to CD3ζ phosphorylation and at 0°C. Moreover, we demonstrate that soluble monovalent pMHC alone induces signaling and reduces TCRαβ cohesion with CD3ζ in membrane-bound or solubilised TCR-CD3. Our data provide compelling evidence that pMHC binding suffices to activate allosteric changes propagating from TCRαβ to the CD3 subunits, reconfiguring interchain transmembrane region interactions. These dynamic modifications could change the arrangement of TCR-CD3 boundary lipids to license CD3ζ phosphorylation and initiate signal propagation.

Immergersi in un'opera pittorica, da spettatore a protagonista della scena rappresentata, è stato da sempre, da parte di chi ama l'arte, un sogno ricorrente, ancor più suggestivo se la scena è la rappresentazione di Gesù con gli Apostoli nei suoi ultimi momenti. Il caso di studio è la splendida "Ultima Cena" dell'artista fiammingo "Gaspar Hovic". La tela, dipinta ad olio (tardo XV sec. d. C.) e custodita nella Chiesa Matrice S. M. Veterana di Triggiano (BA), è stata riprodotta e sceneggiata in un contesto architettonico dall'aspetto suggestivo, con l'uso e l'integrazione di innovative tecnologie: la fotogrammetria digitale, la modellazione solida, la fotografia immersiva. Dopo uno studio storico-artistico dell'opera e l'approfondimento dei concetti della geometria descrittiva, sono stati realizzati virtualmente il luogo, la raffigurazione di oggetti ed i protagonisti, materializzando in 3D l'intera scena. Il paradigma informatico della Realtà Virtuale (Virtual Reality - VR) proietta lo spettatore in modo immersivo nel contesto tridimensionale, attraverso l'uso di visori VR, consentendogli di "entrare" nella tela ed osservare l'opera da inesplorati punti di vista, che in una rappresentazione 2D sono celati. L'opera è così arricchita da nuovi tratti ed elementi pittorici e valorizzata dalla visione fruibile del messaggio artistico dell'autore, tra le incongruenze architettoniche degli elementi dipinti o il gioco di prospettive che mettono in risalto le situazioni sceneggiate.