From 3-geometry transition amplitudes to graviton states

18 pagesIn various background independent approaches, quantum gravity is defined in terms of a field propagation kernel: a sum over paths interpreted as a transition amplitude between 3-geometries, expected to project quantum states of the geometry on the solutions of the Wheeler-DeWitt equation. We study the relation between this formalism and conventional quantum field theory methods. We consider the propagation kernel of 4d Lorentzian general relativity in the temporal gauge, defined by a conventional formal Feynman path integral, gauge fixed à la Fadeev-Popov. If space is compact, this turns out to depend only on the initial and final 3-geometries, while in the asymptotically flat case it depends also on the asymptotic proper time. We compute the explicit form of this kernel at first order around flat space, and show that it projects on the solutions of all quantum constraints, including the Wheeler-DeWitt equation, and yields the correct vacuum and n-graviton states. We also illustrate how the Newtonian interaction is coded into the propagation kernel, a key open issue in the spinfoam approach

Post-Cimmerian (Jurassic–Cenozoic) paleogeography and vertical axis tectonic rotations of Central Iran and the Alborz Mountains

According to previous paleomagnetic analyses, the northward latitudinal drift of Iran related to the closure of the Paleo-Tethys Ocean resulted in the Late Triassic collision of Iran with the Eurasian plate and Cimmerian orogeny. The post-Cimmerian paleogeographic and tectonic evolution of Iran is instead less well known. Here we present new paleomagnetic data from the Upper Jurassic Bidou Formation of Central Iran, which we used in conjunction with published paleomagnetic data to reconstruct the history of paleomagnetic rotations and latitudinal drift of Iran during the Mesozoic and Cenozoic. Paleomagnetic inclination values indicate that, during the Late Jurassic, the Central-East-Iranian Microcontinent (CEIM), consisting of the Yazd, Tabas, and Lut continental blocks, was located at low latitudes close to the Eurasian margin, in agreement with the position expected from apparent polar wander paths (APWP) incorporating the so-called Jurassic massive polar shift, a major event of plate motion occurring in the Late Jurassic from 160 Ma to 145–140 Ma. At these times, the CEIM was oriented WSW–ENE, with the Lut Block bordered to the south by the Neo-Tethys Ocean and to the southeast by the Neo-Sistan oceanic seaway. Subsequently, the CEIM underwent significant counter-clockwise (CCW) rotation during the Early Cretaceous. This rotation may have resulted from the northward propagation of the Sistan rifting- spreading axis during Late Jurassic–Early Cretaceous, or to the subsequent (late Early Cretaceous?) eastward subduction and closure of the Sistan oceanic seaway underneath the continental margin of the Afghan Block. No rotations of, or within, the CEIM occurred during the Late Cretaceous–Oligocene, whereas a second phase of CCW rotation occurred after the Middle-Late Miocene. Both the Late Jurassic–Early Cretaceous and post Miocene CCW rotations are confined to the CEIM and do not seem to extend to other tectonic regions of Iran. Finally, an oroclinal bending mechanism is proposed for the origin of the curved Alborz Mountains, which acquired most of its curvature in the last 8 Myr

Fluvial inverse modelling for inferring the timing of Quaternary uplift in the Simbruini range (Central Apennines, Italy)

The regional topography of the Central Apennines results from convergence between the African and Eurasian plates that led to the formation of a Neogene NE-verging imbricate fold and thrust belt. During the final stages of the orogenic deformations, the whole area was affected by strong uplift and by extensional faulting oriented along the main direction of the Apennine chain. In this framework, the landscape evolution in subaerial conditions started diachronically and is testified by the relicts of clastic deposit at different height from base levels of the present drainage network. In the Simbruini range, there are no absolute dating records neither of the most ancient clastic units deposited after the Messinian thrust-top facies nor of tectonic events. Trying to fill this gap, we used geomorphometric analyses to infer the timing of the recent phases of the tectonic history of the Simbruini range. Specifically, we identified the main non-lithological knickpoints along the river longitudinal profiles, clustered their altimetric distribution and correlated them with the levels of continental clastic deposits reserved at different elevations. Furthermore, we inferred the uplift history of the range by applying the inverse modelling of the river longitudinal profiles. Assuming a block uplift model, the drainage network cutting the Simbruini range recorded on average about 2.4 Myr of tectonic history, characterized by variable base level fall rates (corresponding to uplift rates). According the average tectonic history, the highest base level fall rate of 690 m My-1 was reached at 1.65 Ma, followed by the minimum of about 370 m My-1 , reached at 0.75 Ma, and by a second rise, up to a present-day value of 660 m My-1

Violacein, an indole-derived purple-colored natural pigment produced by Janthinobacterium lividum, inhibits the growth of head and neck carcinoma cell lines both in vitro and in vivo

Violacein (VIO; 3-[1,2-dihydro-5-(5-hydroxy-1H-indol-3-yl)-2-oxo-3H-pyrrol-3-ylidene]-1,3-dihydro-2H-indol-2-one), an indole-derived purple-colored pigment, produced by a limited number of Gram-negative bacteria species, including Chromobacterium violaceum and Janthinobacterium lividum, has been demonstrated to have anti-cancer activity, as it interferes with survival transduction signaling pathways in different cancer models. Head and neck carcinoma (HNC) represents the sixth most common and one of the most fatal cancers worldwide. We determined whether VIO was able to inhibit head and neck cancer cell growth both in vitro and in vivo. We provide evidence that VIO treatment of human and mouse head and neck cancer cell lines inhibits cell growth and induces autophagy and apoptosis. In fact, VIO treatment increased PARP-1 cleavage, the Bax/Bcl-2 ratio, the inhibition of ERK1 and ERK2 phosphorylation, and the expression of light chain 3-II (LC3-II). Moreover, VIO was able to induce p53 degradation, cytoplasmic nuclear factor kappa B (NF-κB) accumulation, and reactive oxygen species (ROS) production. VIO induced a significant increase in ROS production. VIO administration was safe in BALB/c mice and reduced the growth of transplanted salivary gland cancer cells (SALTO) in vivo and prolonged median survival. Taken together, our results indicate that the treatment of head and neck cancer cells with VIO can be useful in inhibiting in vivo and in vitro cancer cell growth. VIO may represent a suitable tool for the local treatment of HNC in combination with standard therapies

Petrogenesis of Mediterranean lamproites and associated rocks: the role of overprinted metasomatic events in the postcollisional lithospheric upper mantle

High-MgO lamproite and lamproite-like (i.e. lamprophyric) ultrapotassic rocks are recurrent in the Mediterranean and surrounding regions. They are associated in space and time with ultrapotassic shoshonites and high-K calc-alkaline rocks. This magmatism is linked with the geodynamic evolution of the westernmost sector of the Alpine–Himalayan collisional margin, which followed the closure of the Tethys Ocean. Subduc- tion-related lamproites, lamprophyres, shoshonites and high-K calc-alkaline suites were emplaced in the Medi- terranean region in the form of shallow level intrusions (e.g. plugs, dykes and laccoliths) and small volume lava flows, with very subordinate pyroclastic rocks, starting from the Oligocene, in the Western Alps (northern Italy), through the Late Miocene in Corsica (southern France) and in Murcia-Almeria (southeastern Spain), to the Plio- Pleistocene in Southern Tuscany and Northern Latium (central Italy), in the Balkan peninsula (Serbia and Mac- edonia) and in the Western Anatolia (Turkey). The ultrapotassic rocks are mostly lamprophyric, but olivine latitic lavas with a clear lamproitic affinity are also found, as well as dacitic to trachytic differentiated products. Lamp- roite-like rocks range from slightly silica under-saturated to silica over-saturated composition, have relatively low Al2O3, CaO and Na2O contents, resulting in plagioclase-free parageneses, and consist of abundant K-feldspar, phlogopite, diopsidic clinopyroxene and highly forsteritic olivine. Leucite is generally absent, and it is rarely found only in the groundmasses of Spanish lamproites. Mediterranean lamproites and associated rocks share an extreme enrichment in many incompatible trace elements and depletion in High Field Strength Elements and high, and positively correlated Th/La and Sm/La ratios. They have radiogenic Sr and unradiogenic Nd iso- tope compositions, high 207Pb over 206Pb and high time-integrated 232Th/238U. Their composition requires an originally depleted lithospheric mantle source metasomatized by at least two different agents: (1) a high Th/ La and Sm/La (i.e. SALATHO) component deriving from lawsonite-bearing, ancient crustal domains likely hosted in mélanges formed during the diachronous collision of the northward drifting continental slivers from Gondwana; (2) a K-rich component derived from a recent subduction and recycling of siliciclastic sediments. These metasomatic melts produced a lithospheric mantle source characterized by network of felsic and phlogo- pite-rich veins, respectively. Geothermal readjustment during post-collisional events induced progressive melt- ing of the different types of veins and the surrounding peridotite generating the entire compositional spectrum of the observed magmas. In this complex scenario, orogenic Mediterranean lamproites represent rocks that charac- terize areas that were affected by multiple Wilson cycles, as observed in the Alpine–Himalayan Realm

Thermal-induced phase transitions in self-assembled mesostructured films studied by small-angle X-ray scattering

Two examples of phase transition in self-assembled mesostructured hybrid thin films are reported. The materials have been synthesized using tetraethoxysilane as the silica source hydrolyzed with or without the addition of methyltriethoxysilane. The combined use of transmission electron microscopy, small-angle X-ray scattering and computer simulation has been introduced to achieve a clear identification of the organized phases. A structural study of the self-assembled mesophases as a function of thermal treatment has allowed the overall phase transition to be followed. The initial symmetries of mesophases in as-deposited films have been linked to those observed in samples after thermal treatment. The monodimensional shrinkage of silica films during calcination has induced a phase transition from face-centered orthorhombic to body-centered cubic. In hybrid films, instead, the phase transition has not involved a change in the unit cell but a contraction of the cell parameter normal to the substrate

ICSBP Is Essential for the Development of Mouse Type I Interferon-producing Cells and for the Generation and Activation of CD8α+ Dendritic Cells

Interferon (IFN) consensus sequence-binding protein (ICSBP) is a transcription factor playing a critical role in the regulation of lineage commitment, especially in myeloid cell differentiation. In this study, we have characterized the phenotype and activation pattern of subsets of dendritic cells (DCs) in ICSBP−/− mice. Remarkably, the recently identified mouse IFN-producing cells (mIPCs) were absent in all lymphoid organs from ICSBP−/− mice, as revealed by lack of CD11clowB220+Ly6C+CD11b− cells. In parallel, CD11c+ cells isolated from ICSBP−/− spleens were unable to produce type I IFNs in response to viral stimulation. ICSBP−/− mice also displayed a marked reduction of the DC subset expressing the CD8α marker (CD8α+ DCs) in spleen, lymph nodes, and thymus. Moreover, ICSBP−/− CD8α+ DCs exhibited a markedly impaired phenotype when compared with WT DCs. They expressed very low levels of costimulatory molecules (intercellular adhesion molecule [ICAM]-1, CD40, CD80, CD86) and of the T cell area-homing chemokine receptor CCR7, whereas they showed higher levels of CCR2 and CCR6, as revealed by reverse transcription PCR. In addition, these cells were unable to undergo full phenotypic activation upon in vitro culture in presence of maturation stimuli such as lipopolysaccharide or poly (I:C), which paralleled with lack of Toll-like receptor (TLR)3 mRNA expression. Finally, cytokine expression pattern was also altered in ICSBP−/− DCs, as they did not express interleukin (IL)-12p40 or IL-15, but they displayed detectable IL-4 mRNA levels. On the whole, these results indicate that ICSBP is a crucial factor in the regulation of two possibly linked processes: (a) the development and activity of mIPCs, whose lack in ICSBP−/− mice may explain their high susceptibility to virus infections; (b) the generation and activation of CD8α+ DCs, whose impairment in ICSBP−/− mice can be responsible for the defective generation of a Th1 type of immune response

Seroprevalence of Ebola virus infection in Bombali District, Sierra Leone

A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola virus disease survivors and their Community Contacts in Bombali District, Sierra Leone. Our data suggest that the specie of Ebola virus (Zaire) responsible of the 2013-2016 epidemic in West Africa may cause mild or asymptomatic infection in a proportion of cases, possibly due to an efficient immune response

A multidisciplinary study using in vivo tumor models and microfluidic cell-on-chip approach to explore the cross-talk between cancer and immune cells

A full elucidation of events occurring inside the cancer microenvironment is fundamental for the optimization of more effective therapies. In the present study, the cross-talk between cancer and immune cells was examined by employing mice deficient (KO) in interferon regulatory factor (IRF)-8, a transcription factor essential for induction of competent immune responses. The in vivo results showed that IRF-8 KO mice were highly permissive to B16.F10 melanoma growth and metastasis due to failure of their immune cells to exert proper immunosurveillance. These events were found to be dependent on soluble factors released by cells of the immune system capable of shaping the malignant phenotype of melanoma cells. An on-chip model was then generated to further explore the reciprocal interactions between the B16.F10 and immune cells. B16.F10 and immune cells were co-cultured in a microfluidic device composed of three culturing chambers suitably inter-connected by an array of microchannels; mutual interactions were then followed using time-lapse microscopy. It was observed that WT immune cells migrated through the microchannels towards the B16.F10 cells, establishing tight interactions that in turn limited tumor spread. In contrast, IRF-8 KO immune cells poorly interacted with the melanoma cells, resulting in a more invasive behavior of the B16.F10 cells. These results suggest that IRF-8 expression plays a key role in the cross-talk between melanoma and immune cells, and under-score the value of cell-on-chip approaches as useful in vitro tools to reconstruct complex in vivo microenvironments on a microscale level to explore cell interactions such as those occurring within a cancer immunoenvironment

Opening of the Neo-Tethys Ocean and the Pangea B to Pangea A transformation during the Permian

We studied the stratigraphy, composition, and paleomagnetic properties of lateritic weathering profiles of Permian age from northern Iran and western Karakoram, Pakistan. A limited set of samples deemed representative yielded stable low-inclination paleomagnetic components carried essentially by hematite of chemical origin isolated in massive, fine-grained, and homogeneous ferricrete facies. These laterites originated at equatorial paleolatitudes characterized by intense weathering processes under warm and humid climatic conditions. Paleomagnetic estimates of paleolatitude from Iran, Karakoram, and north Tibet from this study and the literature, albeit sparse, provide testable constraints on the motion of the Cimmerian terranes as the result of the opening of the Neo-Tethys Ocean along the eastern margin of Gondwana during the Permian. We confirm and help refine previous suggestions that the Cimmerian terranes migrated from southern Gondwanan paleolatitudes in the Early Permian to subequatorial paleolatitudes by the Middle Permian – Early Triassic. As a novel conclusion, we find that timing, rates, and geometry of Cimmerian tectonics are broadly compatible with the transformation of Pangea from an Irvingian B to a Wegenerian A-type configuration with Neo-Tethyan opening taking place contemporaneously essentially in the Permian