NGF-response of EGF-dependent progenitor cells obtained from human sympathetic ganglia

SIGNALLING molecules are thought to play a significant role in determining the fate of neural crest progenitor cells. The human sympathetic chain was identified at 6.5, 7.5, 8.2, 10.2 and 11.4 postconception (PC) weeks demonstrating low affinity nerve growth factor (NGF) receptors, and was processed for tissue culture. In the presence of epidermal growth factor (EGF), floating spheres of proliferating progenitor cells were developed in vitro. In the absence of EGF progenitor cells differentiated into tyrosine hydroxylase (TH)-immunoreactive neuronal and TH-negative flat cells. NGF treatment significantly increased neurite outgrowth and survival of TH-immunoreactive cells. The multipotent cells we isolated differ from previously reported sympathoadrenal progenitors in that they give rise to TH immunoreactive neurones precociously sensitive to NGF

A new test for equilibrium based on clinopyroxene-melt pairs: Clues on the solidification temperatures of Etnean alkaline melts at post-eruptive conditions

We have performed new global regression analyses to calibrate a model of equilibrium between clinopyroxene and co-existing melt. Then we have applied this model to a restricted but important range of clinopyroxene and melt compositions from Mt. Etna volcano. The degree of disequilibrium is determined through the comparison between components “predicted” for clinopyroxene via regression analyses of clinopyroxene-liquid pairs in equilibrium conditions, with those “measured” in the analyzed crystals. The model is tested using compositions not included into the calibration dataset, i.e., clinopyroxene-melt pairs obtained from equilibrium and cooling rate experiments conducted at ambient pressure on an Etnean trachybasalt. The experiments were duplicated at the NNO+1.5 and QFM oxygen buffering conditions estimated for magmas at Mt. Etna. Both equilibrium and disequilibrium clinopyroxene-melt pairs from the experiments were also used as input data for one of the most recent thermometers based on the Jd-DiHd exchange reaction. Results from calculations indicate that, under rapid cooling rate conditions, clinopyroxenes do not equilibrate with the melt. Consequently, the thermometers predict higher crystallization temperatures compared to the final experimental temperature, prior to rapid quenching of the experiment. The systematic difference between expected and measured compositions and temperatures allows us to calibrate a model that describes undercooling based on disequilibrium exchange reactions. We use this new tool to estimate the thermal history of naturally cooled lava flows and dikes at Mt. Etna volcano

Carbonate assimilation in magmas: a reappraisal based on experimental petrology

The main effect of magma-carbonate interaction on magma differentiation is the formation of a silica-undersaturated, alkali-rich residual melt. Such a desilication process was explained as the progressive dissolution of CaCO3 in melt by consumption of SiO2 and MgO to form diopside sensu stricto. Magma chambers emplaced in carbonate substrata, however, are generally associated with magmatic skarns containing clinopyroxene with a high Ca-Tschermak activity in their paragenesis. Data are presented from magma-carbonate interaction experiments, demonstrating that carbonate assimilation is a complex process involving more components than so far assumed. Experimental results show that, during carbonate assimilation, a diopside-hedenbergite-Ca-Tschermak clinopyroxene solid solution is formed and that Ca-Tschermak/diopside and hedenbergite/diopside ratios increase as a function of the progressive carbonate assimilation. Accordingly, carbonate assimilation reaction should be written as follows, taking into account all the involved magmatic components: CaCO3solid+SiO2melt+MgOmelt+FeOmelt+Al2O3melt → (Di-Hd-CaTs)sssolid+CO2fluid The texture of experimental products demonstrates that carbonate assimilation produces three-phases (solid, melt, and fluid) whose main products are: i) diopside-hedenbergite-Ca-Tschermak clinopyroxene solid solution; ii) silica-undersaturated CaO-rich melt; and iii) C-O-H fluid phase. The silica undersaturation of the melt and, more importantly, the occurrence of a CO2-rich fluid phase, must be taken into account as they significantly affect partition coefficients and the redox state of carbonated systems, respectively

International cooperation during volcanic crisis: an example from the Italy-El Salvador monitoring system installed at Chaparrastique volcano, El Salvador

On December 29th, 2013, after 12 years of inactivity, a new explosive eruption occurred at Chaparrastique volcano (San Miguel, el Salvador) prompting the evacuation of more than 5000 people. The new eruption that occurred at the volcano has so far been an isolated single explosion of vulcanian type, and was the first eruption since 2002, when the volcano produced a small VEI 1 eruption. The explosion produced an ash plume of considerable (5-10 km) height, generating heavy ash fall in nearby areas downwind, such as in the towns of Chinameca and San Jorge. Pyroclastic density currents also affected the flanks, damaging the coffee plantations and small inhabited areas around the volcano. On January 2014, following a request of support by the government of El Salvador, INGV (Istituto Nazionale di Geofisica e Vulcanologia), organized a task force, V-Emer (Volcano Emergency) to improve the existing monitoring network at Chaparrastque volcano. During a 10 days campaign in El Salvador a temporary network was successfully installed, and it is now run by the volcanologists of MARN (Ministerio de Medio Ambiente y Recursos Naturales, El Salvador). The network is composed of five broadband seismic stations, 3 infrasonic microphones, 2 radiometers, 10 GPS stations, 1 thermal camera, 1 DOAS and 1 multi-gas geochemical station for measurement of SO2 and CO2 fluxes, respectively. Since 27 January, significant collaborative efforts are being done between MARN and INGV for the processing and interpretation of the data collected during monitoring. For facilitating communication and exchange between the members of the cooperation, a mailing list has been created, and weekly meetings are attended by the members for the discussion on a number of scientific and technical aspects. This initiative seeks to make significant advance into volcano monitoring network and data analysis, as well as improving international cooperation during volcanic crisis management. V-EMER group: A. Bonforte, G. Giuffrida,A. La Spina, F. Montalvo, M. Liuzzo, S. Rapisarda, G. Salerno, D. Andronico, E. Biale, A. Cannata, T. Caltabiano, E. Del Bello, M. La Rocca, D. Granieri, L. Lodato, G. Giudice, F. Murè, E. Pecora, M. Prestifilippo, L. Scuderi, L. Zuccarello, G. De Natale, R. Favara, E. Privitera. MARN group: M. Diaz, D. Escobar, E. Gutierrez, D. Hernandez, G. Marroquin, C. Bolaños, L. Handal, C. Polío, B. Palacios, N. Galvez, R. Torres, E. Escobar

Multilayer Regulation of Neisseria meningitidis NHBA at Physiologically Relevant Temperatures

Neisseria meningitidis colonizes the nasopharynx of humans, and pathogenic strains can disseminate into the bloodstream, causing septicemia and meningitis. NHBA is a surface-exposed lipoprotein expressed by all N. meningitidis strains in different isoforms. Diverse roles have been reported for NHBA in heparin-mediated serum resistance, biofilm formation, and adherence to host tissues. We determined that temperature controls the expression of NHBA in all strains tested, with increased levels at 30–32◦C compared to 37◦C. Higher NHBA expression at lower temperatures was measurable both at mRNA and protein levels, resulting in higher surface exposure. Detailed molecular analysis indicated that multiple molecular mechanisms are responsible for the thermoregulated NHBA expression. The comparison of mRNA steady-state levels and half-lives at 30◦C and 37◦C demonstrated an increased mRNA stability/translatability at lower temperatures. Protein stability was also impacted, resulting in higher NHBA stability at lower temperatures. Ultimately, increased NHBA expression resulted in higher susceptibility to complement-mediated killing. We propose that NHBA regulation in response to temperature downshift might be physiologically relevant during transmission and the initial step(s) of interaction within the host nasopharynx. Together these data describe the importance of NHBA both as a virulence factor and as a vaccine antigen during neisserial colonization and invasion

Effect of glass on the frictional behavior of basalts at seismic slip rates

We performed 31 friction experiments on glassy basalts (GB) and glass-free basalts (GFB) at slip rates up to 6.5 m s−1 and normal stress up to 40 MPa (seismic conditions). Frictional weakening was associated to bulk frictional melting and lubrication. The weakening distance (Dw) was about 3 times shorter in GB than in GFB, but the steady state friction was systematically higher in GB than in GFB. The shorter Dw in GB may be explained by the thermal softening occurring at the glass transition temperature (Tg ~500°C), which is lower than the bulk melting temperature (Tm ~1250°C) of GFB. Postexperiment microanalyses suggest that the larger crystal fraction measured in GB melts results in the higher steady state friction value compared to the GFB melts. The effect of interstitial glass is to facilitate frictional instability and rupture propagation in GB with respect to GFB

Теоретичні аспекти та проблеми вивчення давньоруських бібліотек

У статті відбито сучасну тенденцію в гуманітарній науці, де відбувається подальша міждисциплінарна інтеграція, спостерігається застосування різних методологічних підходів, які доповнюють та збагачують один одного; інтеграція спеціальних історичних дисциплін, їх поступова трансформація в замкнену галузь знання. У нашому випадку це – історичне бібліотекознавство і його новий напрям, який пропонує автор статті, – бібліотечне пам’яткознавство.В статье отображена современная тенденция в гуманитарной науке, где происходит дальнейшая междисциплинарная интеграция, наблюдается применение различных методологических подходов, которые дополняют и обогащают друг друга: интеграция специальных исторических дисциплин, их постепенная трансформация в замкнутую отрасль знаний. В нашем случае это историческое библиотековедение и его новое направление, которое предлага- ет автор статьи, – библиотечное памятниковедение.The article reflects the modern trends in humanitarian science for further interdisciplinary integration, and the use of different methodological approaches that complement each other, as well as describes an integration of special historical disciplines, and graduate transformation into the sphere of the general knowledge. In our case we look at the historical librarian studies and specifically at the branch offered by the author, – librarian study of monuments

Moraxella catarrhalis evades neutrophil oxidative stress responses providing a safer niche for nontypeable Haemophilus influenzae

Moraxella catarrhalis and nontypeable Haemophilus influenzae (NTHi) are pathogenic bacteria frequently associated with exacerbation of chronic obstructive pulmonary disease (COPD), whose hallmark is inflammatory oxidative stress. Neutrophils produce reactive oxygen species (ROS) which can boost antimicrobial response by promoting neutrophil extracellular traps (NET) and autophagy. Here, we showed that M. catarrhalis induces less ROS and NET production in differentiated HL-60 cells compared to NTHi. It is also able to actively interfere with these responses in chemically activated cells in a phagocytosis and opsonin-independent and contact-dependent manner, possibly by engaging host immunosuppressive receptors. M. catarrhalis subverts the autophagic pathway of the phagocytic cells and survives intracellularly. It also promotes the survival of NTHi which is otherwise susceptible to the host antimicrobial arsenal. In-depth understanding of the immune evasion strategies exploited by these two human pathogens could suggest medical interventions to tackle COPD and potentially other diseases in which they co-exist

Decarbonation and thermal microcracking under magmatic P-T-fCO2 conditions: the role of skarn substrata in promoting volcanic instability

We present a systematic study on the influence of pressure (0.1-600 MPa), temperature (750- 1200oC), carbon dioxide fugacity (logfCO2 = -4.41 to 3.60) and time (2-12 hr) on the chemical and physical properties of carbonate rock. Our experiments aim to reproduce the conditions at the periphery of magma chamber where carbonate host rock is influenced by, but not readily assimilated by, magma. This permits the investigation of the natural conditions at which circulating fluids/gases promote infiltration reactions typical of metasomatic skarns that can involve large volumes of subvolcanic carbonate basements. Results show that, providing that carbon dioxide is retained in the pore space, decarbonation does not proceed at any magmatic pressure and temperature. However, when the carbon dioxide is free to escape, decarbonation can occur rapidly and is not hindered by a low initial porosity or permeability. Together with carbon dioxide and lime, portlandite, a mineral commonly found in voluminous metasomatic skarns, readily forms during carbonate decomposition. Post-experimental analyses highlight that thermal microcracking, a result of the highly anisotropic thermal expansion of calcite, exerts a greater influence on rock physical properties (porosity, ultrasonic wave velocities and elastic moduli) than decarbonation. Our data suggest that this will be especially true at the margins of dykes or magma bodies, where temperatures can reach up to 1200oC. However, rock compressive strength is significantly reduced by both thermal cracking and decarbonation, explained by the relative weakness of lime + portlandite compared to calcite, and an increase in grain size with increasing temperature. Metasomatic skarns, whose petrogenetic reactions may involve a few tens of cubic kilometres, could therefore represent an important source of volcanic instability. © The Authors 2013 Published by Oxford University Press on behalf of The Royal Astronomical Society