Vacuum heat treatments of titanium porous structures

Additive manufacturing (AM) of Ti-6Al-4V enables rapid fabrication of complex parts, including porous lattices which are of interest for aerospace, automotive, or biomedical applications, however currently the fatigue resistance of these materials is a critical limitation. Engineering the alloy microstructure provides a promising method for increasing fatigue strength, but conventional heat treatment procedures are known to produce atypical results for AM and porous samples, and must therefore be optimised for these materials. Using vacuum heat treatment, microstructures comparable to those observed for conventional wrought and heat treated alloys were achieved with porous AM Ti-6Al-4V. Fine lamellar microstructures were produced using sub-transus heat treatment at 920 °C, while coarse lamellar microstructures were produced using super-transus heat treatment at 1050 °C or 1200 °C. Increasing the heat treatment temperature increased the elastic modulus from 2552 ± 22 MPa to a maximum of 2968 ± 45 MPa, due to strut sintering increasing the effective strut thickness, and removal of prior β-grain orientation. Heat treatment eliminated the brittle α’ martensite phase in favour of an α + β mixture, where the phase boundaries and β-phase provide greater resistance to crack propagation. Super-transus heat treatments increased the α-lath size which typically reduces crack propagation resistance, however strut sintering reduced surface crack initiation sites, increasing the fatigue strength by 75% from 4.86 MPa for the as-built material to a maximum of 8.51 MPa after 1200 °C heat treatment. This work demonstrates that vacuum heat treatment is effective at tuning the micro- and macro-structure of porous AM Ti-6Al-4V, thereby improving the crucial fatigue resistance

Frontal brain asymmetries as effective parameters to assess the quality of audiovisual stimuli perception in adult and young cochlear implant users

How is music perceived by cochlear implant (CI) users? This question arises as "the next step" given the impressive performance obtained by these patients in language perception. Furthermore, how can music perception be evaluated beyond self-report rating, in order to obtain measurable data? To address this question, estimation of the frontal electroencephalographic (EEG) alpha activity imbalance, acquired through a 19-channel EEG cap, appears to be a suitable instrument to measure the approach/withdrawal (AW index) reaction to external stimuli. Specifically, a greater value of AW indicates an increased propensity to stimulus approach, and vice versa a lower one a tendency to withdraw from the stimulus. Additionally, due to prelingually and postlingually deafened pathology acquisition, children and adults, respectively, would probably differ in music perception. The aim of the present study was to investigate children and adult CI users, in unilateral (UCI) and bilateral (BCI) implantation conditions, during three experimental situations of music exposure (normal, distorted and mute). Additionally, a study of functional connectivity patterns within cerebral networks was performed to investigate functioning patterns in different experimental populations. As a general result, congruency among patterns between BCI patients and control (CTRL) subjects was seen, characterised by lowest values for the distorted condition (vs. normal and mute conditions) in the AW index and in the connectivity analysis. Additionally, the normal and distorted conditions were significantly different in CI and CTRL adults, and in CTRL children, but not in CI children. These results suggest a higher capacity of discrimination and approach motivation towards normal music in CTRL and BCI subjects, but not for UCI patients. Therefore, for perception of music CTRL and BCI participants appear more similar than UCI subjects, as estimated by measurable and not self-reported parameters

Parallaxes of southern extremely cool objects III : 118 L and T dwarfs

We present new results from the Parallaxes of Southern Extremely Cool dwarfs program to measure parallaxes, proper motions and multiepoch photometry of L and early T dwarfs. The observations were made on 108 nights over the course of 8 yr using the Wide Field Imager on the ESO 2.2m telescope. We present 118 new parallaxes of L and T dwarfs of which 52 have no published values and 24 of the 66 published values are preliminary estimates from this program. The parallax precision varies from 1.0 to 15.5mas with a median of 3.8mas. We find evidence for two objects with long term photometric variation and 24 new moving group candidates. We cross-match our sample to published photometric catalogues and find standard magnitudes in up to 16 pass-bands from which we build spectral energy distributions and H-R diagrams. This allows us to confirm the theoretically anticipated minimum in radius between stars and brown dwarfs across the hydrogen burning minimum mass. We find the minimum occurs between L2 and L6 and verify the predicted steep dependence of radius in the hydrogen burning regime and the gentle rise into the degenerate brown dwarf regime. We find a relatively young age of ~2 Gyr from the kinematics of our sample.Peer reviewedFinal Accepted Versio

NPARSEC : NTT Parallaxes of Southern Extremely Cool objects. Goals, targets, procedures and first results

The discovery and subsequent detailed study of T dwarfs have provided many surprises and pushed the physics and modelling of cool atmospheres in unpredicted directions. Distance is a critical parameter for studies of these objects to determine intrinsic luminosities, test binarity and measure their motion in the Galaxy. We describe a new observational programme to determine distances across the full range of T-dwarf subtypes using the New Technology Telescope (NTT)/SOFI telescope/instrument combination. We present preliminary results for ten objects, five of which represent new distances.Peer reviewe

PCDD/Fs in sediments of Central Vietnam coastal lagoons: In search of TCDD

Samples from nine Central Vietnam coastal lagoons, together with three soils and sediments collected in 24 two freshwater reservoirs of the Thua Thien-Hué province, were analysed for polychlorinated dibenzo-p- 25 dioxins and dibenzofurans (PCDD/Fs). Total concentrations are low, from 192 to 2912 pg g1 and depth 26 profiles in Tam Giang-Cau Hai (TG-CH) sediment cores show only minor changes over time in PCDD/F 27 input and composition. Octachloro dibenzo-p-dioxin (OCDD) is the prevailing congener (approximately 28 90%), indicating combustion as the main PCDD/F source to these coastal systems, whereas natural forma- 29 tion might be partly responsible for the presence at depth. 2,3,7,8-Tetrachloro dibenzo-p-dioxin (TCDD), 30 largely sprayed together with Agent Orange over the study areas during the war (1961–1971), is absent 31 or very low. This result supports the hypothesis of strong degradation soon after spraying. Multivariate 32 statistical analyses account for the presence of local, short-range sources as observed in the northern part 33 of the TG-CH lagoon

Fecal microbiota and inflammatory and antioxidant status of obese and lean dogs, and the effect of caloric restriction

IntroductionObesity is the most common nutritional disease in dogs, and is generally managed by caloric restriction. Gut microbiota alteration could represent a predisposing factor for obesity development, which has been associated with a low-grade inflammatory condition and an impaired antioxidant status. Besides, weight loss has been shown to influence the gut microbiota composition and reduce the inflammatory response and oxidative stress. MethodHowever, these insights in canine obesity have not been fully elucidated. The aim of this study was to assess the differences in serum and inflammatory parameters, antioxidant status, fecal microbiota and bacterial metabolites in 16 obese and 15 lean client-owned dogs and how these parameters in obese may be influenced by caloric restriction. First, for 30 days, all dogs received a high-protein, high-fiber diet in amounts to maintain their body weight; later, obese dogs were fed for 180 days the same diet in restricted amounts to promote weight loss. ResultsBefore the introduction of the experimental diet (T0), small differences in fecal microbial populations were detected between obese and lean dogs, but bacterial diversity and main bacterial metabolites did not differ. The fecal Dysbiosis Index (DI) was within the reference range (< 0) in most of dogs of both groups. Compared to lean dogs, obese dogs showed higher serum concentrations of acute-phase proteins, total thyroxine (TT4), and antioxidant capacity. Compared to T0, dietary treatment affected the fecal microbiota of obese dogs, decreasing the abundance of Firmicutes and increasing Bacteroides spp. However, these changes did not significantly affect the DI. The caloric restriction failed to exert significative changes on a large scale on bacterial populations. Consequently, the DI, bacterial diversity indices and metabolites were unaffected in obese dogs. Caloric restriction was not associated with a reduction of inflammatory markers or an improvement of the antioxidant status, while an increase of TT4 has been observed. DiscussionIn summary, the present results underline that canine obesity is associated with chronic inflammation. This study highlights that changes on fecal microbiota of obese dogs induced by the characteristics of the diet should be differentiated from those that are the consequence of the reduced energy intake

Persistent Organic Pollutant in the Venetian coastal environment

The Venetian coastal area is characterized by a strong anthropogenic impact and its quality is very important because of local economical activities, such as tourism or fishing. In the context of the Water Framework Directive (WFD, 2000/60/EC), the aim of the project Q-ALiVe (Qualità dell’Ambiente Litoraneo Veneto) is to check the environmental quality of the Venetian coastal area and whether rivers contamination could influence it. We studied an area going from the mouth of the Adige river to the Malamocco inlet of the Venice lagoon (including the mouth of the Brenta river and the Chioggia lagoon inlet), to distance from the coast of up to about a kilometer. In this work we presented the data relative to Persistent Organic Pollutants (POPs) as PCBs, PBDEs and PAHs, in samples of seawater. Samples were collected during four different sampling campaigns, in different seasons (June 2011, August 2011, September 2011, November 2011); in each sampling campaign we collected 10 samples of surface water. Analytical samples procedures for POPs include liquid-liquid continuous extraction, followed by an automated purification step, with neutral silica columns. Analysis were made by HRGC-HRMS (PCBs) or HRGC-LRMS (PAHs and PBDEs). Quantification was made by isotope dilution. Results suggest a negligible influence of rivers contamination to the quality of the sea facing the city of Chioggia and the Venice lagoon. Funds for this work were provided, in the framework of Q-ALiVe Project, by the Regione del Veneto - L.R. 15/07

High flow nasal oxygen vs. conventional oxygen therapy over respiratory oxygenation index after esophagectomy: an observational study

Background: Postoperative pulmonary complications after esophagectomy still represent a matter of concern. High flow nasal cannula (HFNC) early after major abdominal and thoracic surgery has demonstrated some advantages over conventional oxygen therapy. Data about respiratory effect of HFNC after esophagectomy is scarce. The primary aim of this study is to investigate if the early use of HFNC after esophagectomy could enhance patients' postoperative respiratory oxygenation (ROX) index and, ultimately, reduce postoperative pneumonia. Methods: In this single center retrospective study all patients undergoing to esophagectomy for cancer from May 2020 to November 2022 were evaluated. Historical cohort (HC) received postoperative oxygen supplementation with Venturi mask or nasal goggles, and a cohort was put under HFNC (HFNC cohort). ROX index, blood gas analysis, radiological atelectasis score (RAS), post-operative complications' data and information on hospital stay have been collected and analyzed. Results: Seventy-one patients were included for the final statistical analysis, 31 in the HFNC and 40 in the HC cohort. Mean age was 64±10 years and body mass index (BMI) was 26 [24-29] kg/m2. ROX index was higher in the HFNC patients than in the HC, 20.8 [16.7-25.9] vs. 14.9 [10.8-18.2] (P<0.0001). In the HFNC cohort patients, pH was higher, 7.42 [7.40-7.44] vs. 7.39 [7.37-7.43] than HC, while PaCO2 was lower in HFNC cohort compared with HC, 39 [36-41] vs. 42 [39-45] mmHg, respectively (P=0.01). RAS was similar between the two cohorts of patients, 1.5±0.98 vs. 1.4±1.04 in the HFNC and the HC cohort, respectively (P=0.611). Lower acute respiratory failure (ARF) rate was recorded among HFNC than HC cohort, 0% vs. 13% respectively, P=0.06. No difference in pneumonia frequency between two cohorts was shown. Conclusions: HFNC improved the ROX index after esophagectomy through significant respiratory rate reduction. This tool should be considered for early respiratory support after extubation in this category of patients, not only as a rescue therapy for ARF, but also to optimize early postoperative respiratory function. Whether this will improve patients' outcomes requires further large randomized controlled trials

Free amino acids in Antarctic aerosol: Potential markers for the evolution and fate of marine aerosol

To investigate the impact of marine aerosols on global climate change it is important to study their chemical composition and size distribution. Amino acids are a component of the organic nitrogen in aerosols and particles containing amino acids have been found to be efficient ice nuclei. The main aim of this study was to investigate the L- and D-free amino acid composition as possible tracers of primary biological production in Antarctic aerosols from three different areas: two continental bases, Mario Zucchelli Station (MZS) on the coast of the Ross Sea, Concordia Station at Dome C on the Antarctic Plateau, and the Southern Ocean near the Antarctic continent. Studying the size distribution of amino acids in aerosols allowed us to characterize this component of the water-soluble organic carbon (WSOC) in marine aerosols near their source and after long-range transport. The presence of only free L-amino acids in our samples is indicative of the prevalence of phytoplanktonic material. Sampling at these three points allowed us to study the reactivity of these compounds during long-range transport. The mean total amino acid concentration detected at MZS was 11 pmol m(-3), a higher percentage of amino acids were found in the fine fraction. The aerosol samples collected at Dome C had the lowest amino acid values (0.7 and 0.8 pmol m(-3)), and the coarse particles were found to have higher concentrations of amino acids compared to the coastal site. The amino acid composition in the aerosol collected at Dome C had also changed compared to the coastal site, suggesting that physical and chemical transformations had occurred during long range transport. During the sampling cruise on the R/V Italica on the Southern Ocean, high concentrations of amino acids were found in the total suspended particles, this we attribute to the presence of intact biological material (as microorganisms or plant material) in the sample