Search

The hole spectral function is calculated in nuclear matter to assess the relevance of nucleon–nucleon short range correlations. The calculation is carried out within the Brueckner scheme of many-body theory by using several nucleon–nucleon realistic interactions. Results are compared with other approaches based on variational methods and transport theory. Discrepancies appear in the high energy region, which is sensitive to short range correlations, and are due to the different many-body treatment more than to the specific NN interaction used. Another conclusion is that the momentum dependence of the G-matrix should be taken into account in any self consistent approach. [Copyright &y& Elsevier]

In this work we characterize and explain the difficulties related to voltammetric measurements in DMEM (Dulbecco's Modified Eagle's Medium) on widespread, commercially available Dropsens carbon screen-printed electrodes. The DMEM effects on the electrodes’ surface is investigated by EIS, before and after 75 CV cycles. HBRS (Hepes Buffered Ringer's Solution) is proposed as alternative cell medium, and validated for the voltammetric monitoring of cell culture lactate production. [ABSTRACT FROM AUTHOR]

Volcanic ashes can threaten the human respiratory system through inhalation. In this study we investigated the physical and chemical characteristics of volcanic ashes from the Pomici di Avellino (PdA) eruption, an Early Bronze Age (ca. 3.9 ka) Plinian event from Somma-Vesuvius volcano, southern Italy, whose wide dispersal affected most of the Italian peninsula. In particular, we analysed particle size, shape, composition, and surface reactivity of samples from both proximal and distal locations. Our results indicate that some tephra layers north of Rome have a phonolitic composition and match that of PdA eruption; they reach grain-sizes <2 μm (∼13.5%), thus having the potential to enter the deep respiratory system. Furthermore, the reactivity in free radical generation makes these products potentially able to cause oxidative stress within cells. While commonly no volcanic hazard assessment is made in areas far from active volcanoes, this study highlights that fine ashes from future similar large eruptions, producing high amount of highly fragmented material, can pose a health hazard even in remote, non-volcanic areas, hundreds of km away from the vent, suggesting that further studies on ash toxicity (e.g., in vitro toxicity studies) are required. [Display omitted] • New compositional data on tephra layers from Mezzano and Vico lakes are provided. • Ashes from Mezzano and Vico lakes are ascribable to the PdA eruption. • Grain-size analyses show that PdA ashes are potentially inhalable in distal areas. • PdA ashes can generate hydroxyl radicals and release iron. • The new data can help assessing health concerns from future Somma-Vesuvius eruptions. [ABSTRACT FROM AUTHOR]

We performed a refined analysis of the data collected with the CHIMERA detector with the aim of searching rare 3- α decay modes near the Hoyle state of 12C. In particular we investigated the direct and sequential decay modes of the Hoyle state including also the recently suggested Efimov state. The comparison of selected events with simulations constrains the precision achievable with measurements in different experimental conditions. We observe good sensitivities to different decay scenarios also in the CHIMERA spherical region notwithstanding its limited angular resolution. The search for the decay of the Efimov state in 12C was performed by using new selection strategies as suggested by simulations. The obtained results are not conclusive, however, we are able to exclude the presence of a sequential decay of this state, while our data could be compatible with its direct decay. [ABSTRACT FROM AUTHOR]

Abstract: A Modular Assay System for Solar System Exploration (MASSE) is being developed to include sample handling, pre-treatment, separation and analysis of biological target compounds by both DNA and protein microarrays. To better design sensitive and accurate initial upstream sample handling of the MASSE instrument, experiments investigating the sensitivity and potential extraction bias of commercially available DNA extraction kits between classes of environmentally relevant prokaryotes such as gram-negative bacteria (Escherichia coli), gram-positive bacteria (Bacillus megatarium), and Archaea (Haloarcula marismortui) were performed. For extractions of both planktonic cultures and spiked Mars simulated regolith, FTA® paper demonstrated the highest sensitivity, with detection as low as ∼1×101 cells and ∼3.3×102 cells, respectively. In addition to the highest sensitivity, custom modified application of FTA® paper extraction protocol is the simplest in terms of incorporation into MASSE and displayed little bias in sensitivity with respect to prokaryotic cell type. The implementation of FTA paper for environmental microbiology investigations appears to be a viable and effective option potentially negating the need for other pre-concentration steps such as filtration and negating concerns regarding extraction efficiency of cells. In addition to investigations on useful technology for upstream sample handling in MASSE, we have also evaluated the potential for μTAS to be employed in the MASSE instrument by employing proprietary lab-on-a-chip development technology to investigate the potential for microfluidic cell lysis of different prokaryotic cells employing both chemical and biological lysis agents. Real-time bright-field microscopy and quantitative PMT detection indicated that that gram positive, gram negative and archaeal cells were effectively lyzed in a few seconds using the microfluidic chip protocol developed. This included employing a lysis buffer with components including lysozyme, Protease, Proteinase K, Tween-20 and TritonX-100. The effectiveness of antibiotics and other chemical lysis agents were also screened and demonstrated partial effectiveness on all three cell types. This work demonstrates a step wise approach to evaluating the efficacy and sensitivity of commercial macro-scale technology and state-of-the-art developmental microfluidic technology under consideration for incorporation into the remotely operated MASSE instrument currently under development at the Carnegie Institution of Washington. [Copyright &y& Elsevier]