191 research outputs found
New directional archeomagnetic data of burned cave sediments from Switzerland and geomagnetic field variations in Central Europe
This paper presents new directional archeomagnetic data from nine Meso-/Neolithic fireplaces, sampled in a cave shelter, at Arconciel, in western Switzerland. Rock magnetic measurements indicate a homogenous magnetic mineralogy in all fireplaces, with magnetite as the main magnetic carrier. The remanent magnetization is stable and generally shows one characteristic directional component. Nine new directions, which were obtained from Arconciel, are combined with 356 other archeomagnetic data from a circular area with a radius of 700km around this site, to obtain a penalized least square spline fit for the past 9000yr. We found in general good agreement with other local compilations, such as the Balkan curve, the regional SCHA.DIF.8k model and with lake sediments from UK, Fennoscandia and Switzerland. Nevertheless, a time lag of several centuries is observed for a declination maximum between the archeomagnetic spline fit and the other European data records around 5900BC. This time lag is also observed in the Swiss lake sediment record; therefore we interpret this shift as a local feature of the Earth's magnetic fiel
Evolution of the solar irradiance during the Holocene
Aims. We present a physically consistent reconstruction of the total solar
irradiance for the Holocene. Methods. We extend the SATIRE models to estimate
the evolution of the total (and partly spectral) solar irradiance over the
Holocene. The basic assumption is that the variations of the solar irradiance
are due to the evolution of the dark and bright magnetic features on the solar
surface. The evolution of the decadally averaged magnetic flux is computed from
decadal values of cosmogenic isotope concentrations recorded in natural
archives employing a series of physics-based models connecting the processes
from the modulation of the cosmic ray flux in the heliosphere to their record
in natural archives. We then compute the total solar irradiance (TSI) as a
linear combination of the jth and jth + 1 decadal values of the open magnetic
flux. Results. Reconstructions of the TSI over the Holocene, each valid for a
di_erent paleomagnetic time series, are presented. Our analysis suggests that
major sources of uncertainty in the TSI in this model are the heritage of the
uncertainty of the TSI since 1610 reconstructed from sunspot data and the
uncertainty of the evolution of the Earth's magnetic dipole moment. The
analysis of the distribution functions of the reconstructed irradiance for the
last 3000 years indicates that the estimates based on the virtual axial dipole
moment are significantly lower at earlier times than the reconstructions based
on the virtual dipole moment. Conclusions. We present the first physics-based
reconstruction of the total solar irradiance over the Holocene, which will be
of interest for studies of climate change over the last 11500 years. The
reconstruction indicates that the decadally averaged total solar irradiance
ranges over approximately 1.5 W/m2 from grand maxima to grand minima
First archaeointensity results from four types of ancient kilns excavated in Burkina Faso (West Africa)
A comparison of Thellier-type and multispecimen paleointensity determinations on Pleistocene and historical lava flows from Lanzarote (Canary Islands, Spain)
Sixteen Miocene, Pleistocene, and historic lava flows have been sampled in Lanzarote (Canary
Islands) for paleointensity analysis with both the Coe and multispecimen methods. Besides obtaining new
data, the main goal of the study was the comparison of paleointensity results determined with two different
techniques. Characteristic Remanent Magnetization (ChRM) directions were obtained in 15 flows, and
12 were chosen for paleointensity determination. In Thellier-type experiments, a selection of reliable
paleointensity determinations (43 of 78 studied samples) was performed using sets of criteria of different
stringency, trying to relate the quality of results to the strictness of the chosen criteria. Uncorrected and
fraction and domain-state corrected multispecimen paleointensity results were obtained in all flows. Results
with the Coe method on historical flows either agree with the expected values or show moderately lower
ones, but multispecimen determinations display a large deviation from the expected result in one case. No
relation can be detected between correct or anomalous results and paleointensity determination quality or
rock-magnetic properties. However, results on historical flows suggest that agreement between both
methods could be a good indicator of correct determinations. Comparison of results obtained with both
methods on seven Pleistocene flows yields an excellent agreement in four and disagreements in three
cases. Pleistocene determinations were only accepted if either results from both methods agreed or a result
was based on a sufficiently large number (n>4) of individual Thellier-type determinations. In most
Pleistocene flows, a VADM around 5 31022 Am2 was observed, although two flows displayed higher values
around 931022 Am2.project
CGL2012-32149 (Ministerio de
Econom ıa y Competitividad, Spain),
project 320/2011 (Ministerio de Medio
Ambiente y Medio Rural y Marino,
Spain) and the European Regional
Development Fund (ERDF)
Development of personalized thrombogenesis and thrombin generation assays to assess endothelial dysfunction in cardiovascular diseases
The study of endothelial dysfunction (ED) is crucial to identify the pathogenetic mechanism(s) and provide indications for patient management in cardiovascular diseases. It is currently hindered by the limited availability of patient-specific primary endothelial cells (ECs). Endothelial colony-forming cells (ECFCs) represent an optimal non-invasive tool to overcome this issue. Therefore, we investigated the use of ECFCs as a substrate in thrombogenesis and thrombin generation assay (TGA) to assess ED. Both assays were set up on human umbilical vein endothelial cells (HUVECs) and then tested on ECFCs obtained from healthy donors. To prove the ability of the assays to detect endothelial activation, ECs stimulated with TNFα were compared with unstimulated ECs. EC activation was confirmed by the upregulation of VCAM-1 and Tissue Factor expression. Both assays discriminated between unstimulated and activated HUVECs and ECFCs, as significantly higher platelet deposition and fibrin formation in thrombogenesis assay, and thrombin generation in TGA, were observed when TNFα-activated ECs were used as a substrate. The amount of fibrin and thrombin measured in the two assays were directly correlated. Our results support the combined use of a thrombogenesis assay and TGA performed on patient-derived ECFCs to provide a personalized global assessment of ED relevant to the patient’s hemostatic profile
The Translation Factor eIF6 Is a Notch-Dependent Regulator of Cell Migration and Invasion
A growing body of evidence indicates that protein factors controlling translation play an important role in tumorigenesis. The protein known as eIF6 is a ribosome anti-association factor that has been implicated in translational initiation and in ribosome synthesis. Over-expression of eIF6 is observed in many natural tumours, and causes developmental and differentiation defects in certain animal models. Here we show that the transcription of the gene encoding eIF6 is modulated by the receptor Notch-1, a protein involved in embryonic development and cell differentiation, as well as in many neoplasms. Inhibition of Notch-1 signalling by γ-secretase inhibitors slowed down cell-cycle progression and reduced the amount of eIF6 in lymphoblastoid and ovarian cancer cell lines. Cultured ovarian cancer cell lines engineered to stably over-expressing eIF6 did not show significant changes in proliferation rate, but displayed an enhanced motility and invasive capacity. Inhibition of Notch-1 signalling in the cells over-expressing eIF6 was effective in slowing down the cell cycle, but did not reduce cell migration and invasion. On the whole, the results suggest that eIF6 is one of the downstream effectors of Notch-1 in the pathway that controls cell motility and invasiveness
Chromosomal aberrations and aneuploidy in oral potentially malignant lesions: distinctive features for tongue
<p>Abstract</p> <p>Background</p> <p>The mucosae of the oral cavity are different at the histological level but appear all equally exposed to common genotoxic agents. As a result of this exposure, changes in the mucosal epithelia may develop giving rise to Oral Potentially Malignant Lesions (OPMLs), which with time may in turn progress to Oral Squamous Cell Carcinomas (OSCCs). Therefore, much effort should be devoted to identify features able to predict the likeliness of progression associated with an OPML. Such features may be helpful in assisting the clinician to establish both appropriate therapies and follow-up schedules. Here, we report a pilot study that compared the occurrence of DNA aneuploidy and chromosomal copy number aberrations (CNAs) in the OPMLs from different oral anatomical subsites.</p> <p>Methods</p> <p>Samples from histologically diagnosed OPMLs were processed for high resolution DNA flow cytometry (hr DNA-FCM) in order to determine the relative DNA content expressed by the DNA index (DI). Additionally, array-Comparative Genomic Hybridization (a-CGH) analysis was performed on DNA obtained from diploid nuclei suspensions directly. When aneuploid nuclei were detected, these were physically separated from diploid nuclei on the base of their DI values by means of a DNA-FCM-Sorter in order to improve the a-CGH analysis.</p> <p>Results</p> <p>Tongue OPMLs were more frequently associated with DNA aneuploidy and CNAs than OPMLs arising from all the other mucosal subsites.</p> <p>Conclusions</p> <p>We suggest that the follow-up and the management of the patients with tongue OPMLs should receive a distinctive special attention. Clearly, this hypothesis should be validated in a prospective clinical study.</p
Epsilon iron oxide: origin of the high coercivity stable low Curie temperature magnetic phase found in heated archeological materials
The identification of epsilon iron oxide (ɛ-Fe2O3) as the low Curie temperature high coercivity stable phase (HCSLT) carrying the remanence in heated archeological samples has been achieved in samples from two archeological sites that exhibited the clearest evidence of the presence of the HCSLT. This uncommon iron oxide has been detected by Confocal Raman Spectroscopy (CRS) and characterized by rock magnetic measurements. Large numbers of ɛ-Fe2O3 microaggregates (in CO) or isolated clusters (in HEL) could be recognized, distributed over the whole sample, and embedded within the ceramic matrix, along with hematite and pseudobrookite and with minor amounts of anatase, rutile, and maghemite. Curie temperature estimates of around 170°C for CO and 190°C for HEL are lower than for pure, synthetic ɛ-Fe2O3 (227°C). This, together with structural differences between the Raman spectra of the archeologically derived and synthetic samples, is likely due to Ti substitution in the ɛ-Fe2O3 crystal lattice. The γ-Fe2O3-ɛ-Fe2O3-α-Fe2O3 transformation series has been recognized in heated archeological samples, which may have implications in terms of their thermal history and in the factors that govern the formation of ɛ-Fe2O3
Tuber donnagotto, a new winter truffle species from Istria, Croatia
Tuber donnagotto is a new winter black truffle belonging to the order
Pezizales and the family Tuberaceae. It grows in winter in the calcareous gravel soil (pH 7.6–7.8) near the Adriatic Sea (Rovinj, Istria, Croatia) in predominantly pine forests (Pinus halepensis). Although similar to other black truffles, it has very irregular and hard
fruit bodies, lobate and knotted in form, with deep irregular cavities reaching the middle of the fruit bodies. These cavities are clearly evident in the cross-section of the fruit bodies. A distinctive characteristic of this truffle is the fact that when it is hermetically closed it can be kept in a refrigerator (2–4 °C) for more than 60 days. Tuber donnagotto has a slight but pleasant odor, reminiscent of boletus (Boletus reticulates, B. edulis). Furthermore, T. donnagotto has yellow-brownish and reticulate-alveolate spores, measuring 20–30 × 20–25 mm
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