406 research outputs found
Atomic Force Microscopy - Laser Scanning Confocal Microscopy imaging protocol for copepod fecal pellets
Within the marine carbon and nitrogen biogeochemical cycles, fecal pellets produced by pelagic and benthic copepods are important microbial activity hotspots as particle substrate for bacteria colonization and as sources of particulate and dissolved organic C and N. We developed a protocol combining Atomic Force Microscopy (AFM) and Laser Scanning Confocal Microscopy (LSCM) to study the peritrophic membrane structure and associated bacteria of fecal pellets produced by a benthic copepod, Paramphiascella fulvofasciata. AFM imaging revealed a fibrillar network structure of the peritrophic membrane, 0.7-5.9 nm thick similar to marine polysaccharides and a-chitin. Bacterial cell volume range was 0.006-0.117 µm3 in liquid. LSCM imaging showed a 3D-heterogeneous microenvironment. This protocol would allow high-resolution interrogation of structural changes and bacterial dynamics within the copepod fecal pellets and other heterogeneous particles such marine snow under environmental conditions
Assembling large, complex environmental metagenomes
The large volumes of sequencing data required to sample complex environments
deeply pose new challenges to sequence analysis approaches. De novo metagenomic
assembly effectively reduces the total amount of data to be analyzed but
requires significant computational resources. We apply two pre-assembly
filtering approaches, digital normalization and partitioning, to make large
metagenome assemblies more comput\ ationaly tractable. Using a human gut mock
community dataset, we demonstrate that these methods result in assemblies
nearly identical to assemblies from unprocessed data. We then assemble two
large soil metagenomes from matched Iowa corn and native prairie soils. The
predicted functional content and phylogenetic origin of the assembled contigs
indicate significant taxonomic differences despite similar function. The
assembly strategies presented are generic and can be extended to any
metagenome; full source code is freely available under a BSD license.Comment: Includes supporting informatio
Naturwall: active timber wall for renovation of existent buildings
The renovation of old buildings is actually the challenge to cope with increased effort in order to reduce climate global change, channeling more investment and awareness in this sense, defining more experimentations and find innovative solutions. The difficulty of carrying out an intervention on the existing buildings necessarily arise from the lack of information on the existing structure and the lack of coordinated processes between the multidisciplinary skills involved, as well as a difficulty to optimize the process that would make it even more competitive on the renovation work instead on the new construction. Naturwall is an innovative energy saving system for existent buildings by using wood in multifunctional components able to mitigate the environmental effort in building management. The project meant to introduce an industrialized design method in the renovation of existing build environment that highlights opportunities gave by "off site" production and parametric design approach, without neglecting the aesthetical values and the possibility to change the architectural image of residential and non residential constructions. The project aims to create a representative model of solution that will be promoted in Italy and widespread in other similar contex
Genótipos de sorgo para ensilagem no norte do RS em 2012.
Editores técnicos: Joseani Mesquita Antunes, Ana LÃdia Variani Bonato, Márcia Barrocas Moreira Pimentel
Monitoring of Alarm Reactions of Red Deer (Cervus elaphus) in a Captive Population in Paneveggio Pale di San Martino Natural Park
Simple Summary After several years of inappropriate management, the pasture inside the enclosure for captive red deer in Paneveggio Pale di San Martino regional Park (TN, Italy) lost its nutritional value, due to the expansion of unpalatable tall grasses. Therefore, several measures to restore a suitable pasture composition were needed. The mowing activity represents a disturbance for the captive deer, which negatively affects the animals' well-being. To establish the more appropriate times/days to perform activities inside the enclosure, we observed the alarm reactions and relative intensity of animals exposed to different visual stimuli presented inside and outside the enclosure. Some differences were highlighted between the males and the nursery (females and fawns) groups. Considering the deer biology and the studied location, the best months in which it would be possible to plan activities inside the enclosure are March, April (if the snow is not present) and August. Data elaboration suggests that the best day to perform activities inside the enclosure is Wednesday because the animals showed less sensitivity to disturbances; Tuesday and Thursday may also be considered additional suitable days. The study analyzes red deer responses to disturbances during the day and different exposures to tourists, to establish the more appropriate times to carry out activities inside the Paneveggio deer enclosure. The alarm reactions of red deer were observed after presenting different types of visual stimuli inside and outside the fence, in order to answer some questions: Which stimuli produce the strongest reactions from the animals? Do animals differently react to stimuli presented outside and inside the fence? On which days and times are the animals more sensitive to disturbances? Are there different reactions between the males and females? The results suggest that the red deer adversely react to the disturbance at different degrees of intensity in relation to day, sex, tourist and where the stimuli are presented. It was observed that during the days with the highest tourist presence, the animals were particularly alarmed; discomfort accumulation produced the highest number of alarm reactions on Monday. For these reasons, it would be opportune to manage the pasture on Tuesday, Wednesday and Thursday, scheduled at specific times of day, preferably far from the estimated presence of tourists
Heat Treated NiP–SiC Composite Coatings: Elaboration and Tribocorrosion Behaviour in NaCl Solution
Tribocorrosion behaviour of heat-treated NiP and NiP–SiC composite coatings was investigated in a 0.6 M NaCl solution. The tribocorrosion tests were performed in a linear sliding tribometer with an electrochemical cell interface. It was analyzed the influence of SiC particles dispersion in the NiP matrix on current density developed, on coefficient of friction and on wear volume loss. The results showed that NiP–SiC composite coatings had a lower wear volume loss compared to NiP coatings. However, the incorporation of SiC particles into the metallic matrix affects the current density developed by the system during the tribocorrosion test. It was verified that not only the volume of co-deposited particles (SiC vol.%) but also the number of SiC particles per coating area unit (and consequently the SiC particles size) have made influence on the tribocorrosion behaviour of NiP–SiC composite coatings
New perspectives in cancer biology from a study of canonical and non-canonical functions of base excision repair proteins with a focus on early steps
Alterations of DNA repair enzymes and consequential triggering of aberrant DNA damage response (DDR) pathways are thought to play a pivotal role in genomic instabilities associated with cancer development, and are further thought to be important predictive biomarkers for therapy using the synthetic lethality paradigm. However, novel unpredicted perspectives are emerging from the identification of several non-canonical roles of DNA repair enzymes, particularly in gene expression regulation, by different molecular mechanisms, such as (i) non-coding RNA regulation of tumour suppressors, (ii) epigenetic and transcriptional regulation of genes involved in genotoxic responses and (iii) paracrine effects of secreted DNA repair enzymes triggering the cell senescence phenotype. The base excision repair (BER) pathway, canonically involved in the repair of non-distorting DNA lesions generated by oxidative stress, ionising radiation, alkylation damage and spontaneous or enzymatic deamination of nucleotide bases, represents a paradigm for the multifaceted roles of complex DDR in human cells. This review will focus on what is known about the canonical and non-canonical functions of BER enzymes related to cancer development, highlighting novel opportunities to understand the biology of cancer and representing future perspectives for designing new anticancer strategies. We will specifically focus on APE1 as an example of a pleiotropic and multifunctional BER protein
APE1 and NPM1 protect cancer cells from platinum compounds cytotoxicity and their expression pattern has a prognostic value in TNBC
Hybrid stars with sequential phase transitions: the emergence of the g mode
Neutron stars are the densest objects in the Universe, with and km, and the equation of state associated to their
internal composition is still unknown. The extreme conditions to which matter
is subjected inside neutron stars could lead to a phase transition in their
inner cores, giving rise to a hybrid compact object. The observation of
binary pulsars (PSR~J1614-2230, PSR~J03430432 and
PSR~J07406620) strongly constraints theoretical models of the equation of
state. Moreover, the detection of gravitational waves emitted during the binary
neutron star merger, GW170817, and its electromagnetic counterpart, GRB170817A,
impose additional constraints on the tidal deformability. In this work, we
investigate hybrid stars with sequential phase transitions hadron-quark-quark
in their cores. We assume that both phase transitions are sharp and analyse the
rapid and slow phase conversion scenarios. For the outer core, we use modern
hadronic equations of state. For the inner core we employ the constant speed of
sound parametrization for quark matter. We analyze more than 3000 hybrid
equations of state, taking into account the recent observational constraints
from neutron stars. The effects of hadron-quark-quark phase transitions on the
normal oscillation modes and , are studied under the Cowling
relativistic approximation. Our results show that, in the slow conversion
regime, a second quark-quark phase transition gives rise to a new ~mode.
We discuss the observational implications of our results associated to the
gravitational waves detection and the possibility of detecting hints of
sequential phase transitions and the associated ~mode.Comment: 24 pages, 9 figure
Integrating sol-gel and carbon dots chemistry for the fabrication of fluorescent hybrid organic-inorganic films
Highly fluorescent blue and green-emitting carbon dots have been designed to be integrated into sol-gel processing of hybrid organic-inorganic materials through surface modification with an organosilane, 3-(aminopropyl)triethoxysilane (APTES). The carbon dots have been synthesised using citric acid and urea as precursors; the intense fluorescence exhibited by the nanoparticles, among the highest reported in the scientific literature, has been stabilised against quenching by APTES. When the modification is carried out in an aqueous solution, it leads to the formation of silica around the C-dots and an increase of luminescence, but also to the formation of large clusters which do not allow the deposition of optically transparent films. On the contrary, when the C-dots are modified in ethanol, the APTES improves the stability in the precursor sol even if any passivating thin silica shell does not form. Hybrid films containing APTES-functionalized C-dots are transparent with no traces of C-dots aggregation and show an intense luminescence in the blue and green range
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