Tuning of the Thermoelectric Figure of Merit of CH3_3NH3_3MI3_3 (M=Pb,Sn) Photovoltaic Perovskites

The hybrid halide perovskites, the very performant compounds in photovoltaic applications, possess large Seebeck coefficient and low thermal conductivity making them potentially interesting high figure of merit ($ZT$) materials. For this purpose one needs to tune the electrical conductivity of these semiconductors to higher values. We have studied the CH$_3$NH$_3$MI$_3$ (M=Pb,Sn) samples in pristine form showing very low $ZT$ values for both materials; however, photoinduced doping (in M=Pb) and chemical doping (in M=Sn) indicate that, by further doping optimization, $ZT$ can be enhanced toward unity and reach the performance level of the presently most efficient thermoelectric materials.Comment: 9 pages, 2 figures + toc figur

Ultra-low thermal conductivity in organic-inorganic hybrid perovskite CH3NH3PbI3

We report on the temperature dependence of thermal conductivity of single crystalline and polycrystalline organometallic perovskite CH3NH3PbI3. The comparable absolute values and temperature dependence of the two sample's morphologies indicate the minor role of the grain boundaries on the heat transport. Theoretical modelling demonstrates the importance of the resonant scattering in both specimens. The interaction between phonon waves and rotational degrees of freedom of CH3NH3+ sub-lattice emerges as the dominant mechanism for attenuation of heat transport and for ultralow thermal conductivity of 0.5 W/(Km) at room temperature

The Role of Transport Agents in MoS2 Single Crystals

We report resistivity, thermoelectric power and thermal conductivity of MoS2 single crystals prepared by chemical vapour transport (CVT) method using I2, Br2 and TeCl4 as transport agents. The material presents low-lying donor and acceptor levels, which dominate the in-plane charge transport. Intercalates into the Van der Waals gap strongly influence the inter-plane resistivity. Thermoelectric power displays the characteristics of strong electron-phonon interaction. Detailed theoretical model of thermal conductivity reveals the presence of high number of defects in the MoS2 structure. We show that these defects are inherent to CVT growth method, coming mostly from the transport agent molecules inclusion as identified by Total Reflection X-ray Fluorescence analysis (TXRF) and in-beam activation analysis (IBAA).Comment: 17 pages, 5 figure

Multi-platform, Multi-scale and Multi-temporal 4D Glacier Monitoring. The Rutor Glacier Case Study

At present most alpine glaciers are not in equilibrium with the current climate, as a result they are undergoing a dramatic mass loss. Monitoring glacial variations is crucial to assess the consequences of climate change on the territory. In this work different geomatics techniques are exploited to measure and monitor the Rutor glacier over the years. In this study two different techniques were adopted to generate 3 digital surface models (DSMs): aerial and satellite photogrammetry. Two photogrammetric aerial surveys were carried out: at the end of the hydrological year 2019/20 and at the end of the following hydrological year. Additionally, a very high-resolution satellite stereo pair, acquired by the Pléiades-1A platform in 2017, was processed to assess whether satellite images can be applied to extract the 3D surface of the Rutor glacier. In order to evaluate the Rutor glacier mass-balance throughout the years several reference points were positioned and measured before the 2021 aerial flight. Thanks to the presence of the materialized points the 2021 model is considered as the ‘Reference Model’ against which subsequent models can be compared for glacier analysis. This model was validated by means of a comparison with the authoritative Regional DSM based on LiDAR surveys. In alpine glaciers, the positioning of artificial square cross target in time invariant areas is crucial to enable a multitemporal 4D analysis. The use of very high-resolution satellite imagery allows large areas to be mapped in 3D, but with lower accuracies proportionally decreasing with respect to slope and exposure

Morphometric parameters for nasal septum deviation identification in CBCT data

Advances in the upper airway imaging allow to better evaluate and understand their morphology, pathology and mechanics [1]. In particular, Cone beam CT technology (CBCT), with its isotropic spatial resolution, undistorted images, X-ray lower radiation exposure, versatility and relatively low cost, takes over other imaging modalities [2]. The purpose of this study is to evaluate whether CBCT scans can be valuable tools for the extraction of quantitative parameters to confirm the deviation of the nasal septum in a specific patient. First, we assessed the difference in angle of septal deviation, calculated as proposed by Orhan et al., among a control group and a patient group [3]. Subsequently, we evaluated the percentage difference between the volume of the upper airways in the right side and left side of the nose in the same sample. The measurements were performed on 23 CBCT scans of Caucasian adult women, divided into 7 control subjects and 16 patients. The results demonstrate that there is a significant difference both in the deviation angle (p<0.05) and in the volume difference between healthy and patient subjects (p<0.001). Duplicate measurements of the deviation angle and the volume found no significant difference (p>0.05); random errors explained 0.77% (angle) and 0.99% (volume) of the sample variance. Paired Student’s t tests were used for comparisons. In particular, the volume difference appears to be less sensitive to the presence of isolated cartilaginous ridges that increase the angle of deviation even if the septum is not pathological. This makes it more suited to the identification of this pathology. The obtained outcomes are encouraging and it is advisable to continue the study on a larger sample

Contribution of mammary epithelial cells to the immune response during early stages of a bacterial infection to Staphylococcus aureus

To differentiate between the contribution of mammary epithelial cells (MEC) and infiltrating immune cells to gene expression profiles of mammary tissue during early stage mastitis, we investigated in goats the in vivo transcriptional response of MEC to an experimental intra mammary infection (IMI) with Staphylococcus aureus, using a non-invasive RNA sampling method from milk fat globules (MFG). Microarrays were used to record gene expression patterns during the first 24 hours post-infection (hpi). This approach was combined with laser capture microdissection of MEC from frozen slides of mammary tissue to analyze some relevant genes at 30 hpi. During the early stages post-inoculation, MEC play an important role in the recruitment and activation of inflammatory cells through the IL-8 signalling pathway and initiate a sharp induction of innate immune genes predominantly associated with the pro-inflammatory response. At 30 hpi, MEC express genes encoding different acute phase proteins, including SAA3, SERPINA1 and PTX3 and factors, such as S100A12, that contribute directly to fighting the infection. No significant change in the expression of genes encoding caseins was observed until 24 hpi, thus validating our experimental model to study early stages of infection before the occurrence of tissue damage, since the milk synthesis function is still operative. This is to our knowledge the first report showing in vivo, in goats, how MEC orchestrate the innate immune response to an IMI challenge with S. aureus. Moreover, the non-invasive sampling method of mammary representative RNA from MFG provides a valuable tool to easily follow the dynamics of gene expression in MEC to search for sensitive biomarkers in milk for early detection of mastitis and therefore, to successfully improve the treatment and thus animal welfare

The HCN domain couples voltage gating andcAMP response in hyperpolarization-activatedcyclic nucleotide-gated channels

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control spontaneous electrical activity in heart and brain. Binding of cAMP to the cyclic nucleotide-binding domain (CNBD) facilitates channel opening by relieving a tonic inhibition exerted by the CNBD. Despite high resolution structures of the HCN1 channel in the cAMP bound and unbound states, the structural mechanism coupling ligand binding to channel gating is unknown. Here we show that the recently identified helical HCN-domain (HCND) mechanically couples the CNBD and channel voltage sensing domain (VSD), possibly acting as a sliding crank that converts the planar rotational movement of the CNBD into a rotational upward displacement of the VSD. This mode of operation and its impact on channel gating are confirmed by computational and experimental data showing that disruption of critical contacts between the three domains affects cAMP- and voltage-dependent gating in three HCN isoforms

The HCN domain couples voltage gating and cAMP response in hyperpolarization-activated cyclic nucleotide-gated channels

Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control spontaneous electrical activity in heart and brain. Binding of cAMP to the cyclic nucleotide-binding domain (CNBD) facilitates channel opening by relieving a tonic inhibition exerted by the CNBD. Despite high resolution structures of the HCN1 channel in the cAMP bound and unbound states, the structural mechanism coupling ligand binding to channel gating is unknown. Here we show that the recently identified helical HCN-domain (HCND) mechanically couples the CNBD and channel voltage sensing domain (VSD), possibly acting as a sliding crank that converts the planar rotational movement of the CNBD into a rotational upward displacement of the VSD. This mode of operation and its impact on channel gating are confirmed by computational and experimental data showing that disruption of critical contacts between the three domains affects cAMP- and voltagedependent gating in three HCN isoforms

Cytogenotoxicity biomarkers in fat snook Centropomus parallelus from Cananéia and São Vicente estuaries, SP, Brazil

The aquatic environment receives many contaminants that can induce damages at the molecular, biochemical, cellular and physiological levels. Centropomus parallelus, an important food resource for local populations, is a predator fish that feeds on small fishes and benthic invertebrates, thus being vulnerable to the bioconcentration and biomagnification processes. This study aimed to evaluate cytogenotoxic responses in erythrocytes from C. parallelus juveniles collected in the Cananéia and São Vicente estuaries, both in winter and in summer. After anesthesia, blood samples were collected by caudal puncture. Blood smears were prepared on glass slides and stained with May-Grünwald-Giemsa dye. Two thousand cells were analyzed per slide (1000x), and nuclear abnormalities (NA) and micronuclei (MN) were scored. The São Vicente sample showed MN and NA frequencies (%/1000 cells) of 0.325 and 3.575, in winter, and of 0.125 and 2.935 in summer respectively; the Cananéia sample showed frequencies of 0.0325 and 0.03, in winter, and of 0.065 and 0.355 in summer, respectively. The rates found in São Vicente were significantly higher than those found in Cananéia, evidencing that the levels of pollution in that estuary were high enough to induce genetic damages