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Nowadays, we are assisting in the exceptional growth in research relating to the development of wearable devices for sweat analysis. Sweat is a biofluid that contains useful health information and allows a non-invasive, continuous and comfortable collection. For this reason, it is an excellent biofluid for the detection of different analytes. In this work, electrochemical sensors based on polyaniline thin films deposited on the flexible substrate polyethylene terephthalate coated with indium tin oxide were studied. Polyaniline thin films were abstained by the potentiostatic deposition technique, applying a potential of +2 V vs. SCE for 90 s. To improve the sensor performance, the electronic substrate was modified with reduced graphene oxide, obtained at a constant potential of −0.8 V vs. SCE for 200 s, and then polyaniline thin films were electrodeposited on top of the as-deposited substrate. All samples were characterized by XRD, SEM, EDS, static contact angle and FT-IR/ATR analysis to correlate the physical-chemical features with the performance of the sensors. The obtained electrodes were tested as pH sensors in the range from 2 to 8, showing good behavior, with a sensitivity of 62.3 mV/pH, very close to a Nernstian response, and a reproducibility of 3.8%. Interference tests, in the presence of competing ions, aimed to verify the selectivity, were also performed. Finally, a real sweat sample was collected, and the sweat pH was quantified with both the proposed sensor and a commercial pH meter, showing an excellent concordance.

We analyse an elliptic equation with critical growth set on a d-dimensional ( d ≥ 3 ) Hadamard manifold ( M , g ) . By adopting a variational perspective, we prove the existence of non-zero non-negative solutions invariant under the action of a specific family of isometries. Our result remains valid when the original nonlinearity is singularly perturbed. Preserving the same variational approach, but considering other groups of isometries, we finally show that when M = R d , d > 3 , and the nonlinearity is odd, there exist at least ( − 1 ) d + [ d − 3 2 ] pairs of sign-changing solutions.

The oxidation behavior of Si- and/or Mn-Ni-25Cr alloys at 1050 °C in air was studied to provide new insights on the effect of minor additions on chromia-scale growth. Four nickel alloys with and without Si or Mn were prepared. Thermogravimetry and post-oxidation characterizations evidenced that manganese increased, whereas silicon addition decreased chromia growth rate. On the contrary, addition of both Si and Mn to the Ni-25Cr alloy led to an unchanged oxidation rate in comparison with the unalloyed Ni-25Cr material. Oxide scales were characterized by photoelectrochemistry (PEC) to evaluate the role of the additions on the point defects nature. The n and p contributions of chromia forming in air were not changed by Si. On the opposite, Mn modified the scale conducting properties since only n contributions were observed for both chromia and Mn1+xCr2−xO4 spinel oxide with Mn-containing samples. In the latter case, the PEC contribution at ~ 3.2–3.4 eV was allocated to the signature of the Mn1+xCr2−xO4 spinel oxide. These data suggested that manganese enhances and silicon limits grain boundary diffusion in chromia scale as reactive element does.

Metal alloys produced by additive manufacturing have specific microstructures and compositions. Their microstructure is generally out of equilibrium, textured, and inhomogeneities can be observed. They can have pores and nano-inclusions. The contents of volatile elements may deviate from the nominal composition. These alloys often experience significant internal stresses and present fairly rough surfaces depending on the process used. Hipping these alloys modifies their microstructure and defects. This literature review shows that open porosity can lead to much higher oxidation kinetics than dense materials, with very deep internal oxide penetrations. Nevertheless, when fabricated with optimized parameters, LBM- or EBM-alloys, such as TA6V, 718, or 316L, can behave as well as, or even better than, wrought alloys. The roughness of the surface is not necessarily problematic, but it can lead to local breakaway phenomena and premature spalling on some alloys. It has been verified that the nature of the grain boundaries strongly affects the intergranular oxidation. The effect of chemical segregations on the protective nature of the outer oxide layer has also been reported. Today, too few studies have been devoted to the effect of raw and pre-oxidized surface states after HIP on cyclic oxidation and on hot corrosion of these alloys.

Dopamine is an important neurotransmitter involved in many human biological processes as well as in different neurodegenerative diseases. Monitoring the concentration of dopamine in biological fluids, i.e., blood and urine is an effective way of accelerating the early diagnosis of these types of diseases. Electrochemical sensors are an ideal choice for real-time screening of dopamine as they can achieve fast, portable inexpensive and accurate measurements. In this work, we present electrochemical dopamine sensors based on reduced graphene oxide coupled with Au or Pt nanoparticles. Sensors were developed by co-electrodeposition onto a flexible substrate, and a systematic investigation concerning the electrodeposition parameters (concentration of precursors, deposition time and potential) was carried out to maximize the sensitivity of the dopamine detection. Square wave voltammetry was used as an electrochemical technique that ensured a high sensitive detection in the nM range. The sensors were challenged against synthetic urine in order to simulate a real sample detection scenario where dopamine concentrations are usually lower than 600 nM. Our sensors show a negligible interference from uric and ascorbic acids which did not affect sensor performance. A wide linear range (0.1–20 μm for gold nanoparticles, 0.1–10 μm for platinum nanoparticles) with high sensitivity (6.02 and 7.19 μA μM-1 cm-2 for gold and platinum, respectively) and a low limit of detection (75 and 62 nM for Au and Pt, respectively) were achieved. Real urine samples were also assayed, where the concentrations of dopamine detected aligned very closely to measurements undertaken using conventional laboratory techniques. Sensor fabrication employed a cost-effective production process with the possibility of also being integrated into flexible substrates, thus allowing for the possible development of wearable sensing devices.

Waste valorization represents one of the main social challenges when promoting a circular economy and environmental sustainability. Here, we evaluated the effect of the polyphenols extracted from apple peels, normally disposed of as waste, on the amyloid aggregation process of ?-casein from bovine milk, a well-used amyloidogenic model system. The effect of the apple peel extract on protein aggregation was examined using a thioflavin T fluorescence assay, Congo red binding assay, circular dichroism, light scattering, and atomic force microscopy. We found that the phenolic extract from the peel of apples of the cultivar "Fuji", cultivated in Sicily (Caltavuturo, Italy), inhibited ?-casein fibril formation in a dose-dependent way. In particular, we found that the extract significantly reduced the protein aggregation rate and inhibited the secondary structure reorganization that accompanies ?-casein amyloid formation. Protein-aggregated species resulting from the incubation of ?-casein in the presence of polyphenols under amyloid aggregation conditions were reduced in number and different in morphology. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

In this work, an electrochemical sensor for uric acid determination is shown with a preliminary study for its validation in real samples (milk and urine). Uric acid can be electrochemically oxidized in aqueous solutions and thus it is possible to obtain electrochemical sensors for this chemical by means of this electrooxidation reaction. Indium tin oxide coated on flexible polyethylene terephthalate substrate, modified with reduced graphene oxide and gold nanoparticles by co-electrodeposition, was used. Electrodeposition was performed at -0.8V vs SCE for 200 s. All samples were characterized by electron scan microscopy and electron diffraction spectroscopy. A careful investigation on the effect of pH was performed to understand its influence on uric acid oxidation. The detection of uric acid was using the linear sweep voltammetry. Results show that the peak current increases linearly with uric acid concentration from 10 to 1000 μM with a limit of detection of about 7.1 μM. The sensor shows high selectivity towards different interferents that can be found in the milk and urine matrix, such as chloride, calcium, sodium and ammonium ions. To prove the applicability of the proposed sensor, uric acid was quantified in real milk and urine samples with excellent results comparable to those of conventional techniques.

In this work, an electrochemical sensor for uric acid determination is shown with a preliminary study for its validation in real samples (milk and urine). Uric acid can be electrochemically oxidized in aqueous solutions and thus it is possible to obtain electrochemical sensors for this chemical by means of this electrooxidation reaction. Indium tin oxide coated on flexible polyethylene terephthalate substrate, modified with reduced graphene oxide and gold nanoparticles by co-electrodeposition, was used. Electrodeposition was performed at -0.8V vs SCE for 200 s. All samples were characterized by electron scan microscopy and electron diffraction spectroscopy. A careful investigation on the effect of pH was performed to understand its influence on uric acid oxidation. The detection of uric acid was using the linear sweep voltammetry. Results show that the peak current increases linearly with uric acid concentration from 10 to 1000 μM with a limit of detection of about 7.1 μM. The sensor shows high selectivity towards different interferents that can be found in the milk and urine matrix, such as chloride, calcium, sodium and ammonium ions. To prove the applicability of the proposed sensor, uric acid was quantified in real milk and urine samples with excellent results comparable to those of conventional techniques.

A sensitive and selective electrochemical sensor, based on reduced graphene oxide and gold nanoparticles obtained by simple co-electrodeposition, was developed for the detection of uric acid and ascorbic acid. Because of the electrochemical oxidation of both uric and ascorbic acid depending on the pH, the sensor performances were studied at different pH values. Excellent results were obtained for uric acid detection in a linear range from 10 to 500 µmol dm−3 with a sensitivity of 0.31 µA cm−2 µM−1. A limit of detection and quantification of 3.6 µM and 10.95 µmol dm−3, respectively, was calculated. Sensors showed good selectivity toward different interfering species present in the matrix of milk, fruit juice and urine (Na+, NH4+, Cl− and glucose). A simultaneous detection of uric acid and ascorbic acid was also carried out reaching a limit of detection of 2.26 and 5.63 µmol dm−3, respectively. Sensors were also validated measuring both acids in real samples of foods and body fluids (commercial milk and fruit juice and urine). Excellent results were achieved in good agreement with conventional techniques.

The cblC disease is an inborn disorder of the vitamin B12 (cobalamin, Cbl) metabolism characterized by methylmalonic aciduria and homocystinuria. The clinical consequences of this disease are devastating and, even when early treated with current therapies, the affected children manifest symptoms involving vision, growth, and learning. The illness is caused by mutations in the gene codifying for MMACHC, a 282aa protein that transports and transforms the different Cbl forms. Here we present data on the structural properties of the truncated protein p.R132X resulting from the c.394C > T mutation that, along with c.271dupA and c.331C > T, is among the most common mutations in cblC. Although missing part of the Cbl binding domain, p.R132X is associated to late-onset symptoms and, therefore, it is supposed to retain residual function. However, to our knowledge structuralfunctional studies on c.394C > T mutant aimed at verifying this hypothesis are still lacking. By using a biophysical approach including Circular Dichroism, fluorescence, Small Angle X-ray Scattering, and Molecular Dynamics, we show that the mutant protein MMACHC-R132X retains secondary structure elements and remains compact in solution, partly preserving its binding affinity for Cbl. Insights on the fragile stability of MMACHCR132X-Cbl are provided.

Il contributo si propone di analizzare la Strategia ad hoc in materia di criminalità organizzata presentata dalla Commissione europea il 14 aprile 2021 al fine di tracciare le linee di intervento prioritarie in tema di contrasto ai gruppi criminali mediante il rafforzamento dello scambio di informazioni e della cooperazione tra le autorità dei singoli Stati e una valutazione in merito alla capacità della Decisione Quadro 2008/841/GAI del Consiglio del 24 ottobre 2008 di garantire un’azione di contrasto efficace alla criminalità organizzata., The paper analyzes the EU Strategy to tackle Organized Crime that was presented by the European Commission on 14 April 2021 with the aim to outline the main areas of intervention in the fight against organized crime groups, to strengthen information exchange and cooperation between member States and evaluate the effectiveness of Framework Decision 2008/841/JHA of 24 October 2008 on the fight against organized crime.

A test rig consisting of a quartz tube placed in a horizontal furnace made of five independently regulated heating zones allowed the evaluation of the metal dusting attack of a FeNiCr alloy. Fifteen samples were exposed in a temperature gradient from 504° to 704°C, 1.1 bar, to a highly carburizing atmosphere for 1500 h. Below 561 °C the high density of pits led to uniform corrosion whereas localized pits developed at higher temperatures. In depth pit growth rate raised to a maximum at 632 °C, then decreased showing that it depends both on temperature and on the carbon activity gradient.

Hydroxytyrosol (HT), one of the main phenolic components of olive oil, has attracted considerable interest for its biological properties, including a remarkable antioxidant and anti-inflammatory power and, recently, for its ability to interfere with the amyloid aggregation underlying several human diseases. We report here a broad biophysical approach and cell biology techniques that allowed us to characterize the molecular mechanisms by which HT affects insulin amyloid aggregation and the related cytotoxicity. Our data show that HT is able to fully inhibit insulin amyloid aggregation and this property seems to be ascribed to the stabilization of the insulin monomeric state. Moreover, HT completely reverses the toxic effect produced by amyloid insulin aggregates in neuroblastoma cell lines by fully inhibiting the production of toxic amyloid species. These findings suggest that the beneficial effects of olive oil polyphenols, including HT, may arise from multifunctional activities and suggest possible a application of this natural compound in the prevention or treatment of amyloid-associated diseases.

In the present work, the Ta-B system was thermodynamically optimized based on the CALPHAD method using data of liquidus temperatures, invariant transformations and enthalpy of formation from the literature as well as new experiments performed in our group. The phases Ta3B2, TaB(rt), Ta5B6, Ta3B4 were modeled as stoichiometric compounds. On the other hand, L (liquid), BCC, Ta2B, TaB(ht) and TaB2 were modeled as solution phases using the Compound Energy Formalism (CEF), with excess terms described by the Redlich-Kister polynomials. (βB) was treated as a pure element without any Ta solubility. The present thermodynamic modeling is in good agreement with the experimental data.

SSCI-VIDE+CARE+PVE:ACV; International audience; Ethylene oxide (EO) is nowadays a chemical intermediate of paramount importance. As one of the highest volume petrochemicals, it serves as a precursor for the further production of added value molecules, including plastics, polyester and ethylene glycol. EO is industrially produced by the partial oxidation (epoxidation) of ethylene with air (or oxygen) on Ag/α-Al2O3 catalysts at low reaction temperatures (around 220 oC) and high pressures (10-30 bar). Silver is the only one known active heterogeneous catalyst for the epoxidation of ethylene. The epoxidation is in competition with the combustion side reactions of both ethylene and EO, leading to the production of CO2 and H2O. The mechanism of the epoxidation and, in particular the nature of the involved oxygen species are under debate. We have designed by reactive magnetron sputtering a solid oxide electrochemical cell based on nanostructured Ag/Gadolinia-Doped Ceria (a well-known O2- conductor) catalyst. We found an unprecedent linear increase of the selectivity towards EO (Fig. 1) and of the ethylene conversion. These results demonstrate that EO can be electrocatalytically produced in a solid oxide electrochemical cell between 220 °C and 300 °C on a nanostructured Ag/GDC electrocatalyst prepared by reactive magnetron sputtering. Despite low values of Faradaic efficiencies, the EO selectivity and the ethylene conversion can be increased at 220 °C with the application of small positive currents (< 1 mA) that correspond to an energy consumption of around ~ 1 mW/cm². This proof-of-concept opens the way for a new environmentally-friendly route (without utilization of chlorinated hydrocarbons) for the epoxidation of ethylene in a solid oxide cell via direct electrooxidation of ethylene. These results also underline the key role of O2- species in the mechanism of ethylene epoxidation on Ag.

International audience; Oxidation of chromia-forming alloys (pure chromium, nickel–chromium alloy and ferritic stainless steel alloy) at temperature ranging from 800 to 1050 °C was conducted on samples with or without gold markers applied prior to testing. Gold is often used as a marker in order to identify oxide growth direction. Its localization inside the oxide scale can demonstrate an inward or an outward growth. It is found that gold particles can be found either at the internal metal/oxide interface or inside the scale or again at the external oxide/gas interface on the same sample (on NiCr and stainless steel alloys). For pure chromium oxidation, gold is found inside the chromia scale, at the equiaxed-columnar interface, as expected from ASTAR-TEM characterization. However, photoelectrochemical characterization has shown that gold can modify the semiconducting chromia properties. Finally, gold is not inert in these several conditions and should not be considered in these present cases, but also more generally in most cases, as an appropriate marker. On the contrary, ASTAR maps may permit to access the oxide growth direction without interfering the studied system.

Blood pressure changes upon standing reflect a hemodynamic response, which depends on the baroreflex system and euvolemia. Dysautonomia and fluctuations in blood volume are hallmarks in kidney failure requiring replacement therapy. Orthostatic hypotension has been associated with mortality in hemodialysis patients, but neither this relationship nor the impact of changes in blood pressure has been tested in patients on peritoneal dialysis. We investigated both these relationships in a cohort of 137 PD patients. The response to orthostasis was assessed according to a standardized protocol. Twenty-five patients (18%) had systolic orthostatic hypotension, and 17 patients (12%) had diastolic hypotension. The magnitude of systolic and diastolic BP changes was inversely related to the value of the corresponding supine BP component (r&nbsp, = −0.16, p = 0.056 (systolic) and r&nbsp, = −0.25, p = 0.003 (diastolic), respectively). Orthostatic changes in diastolic, but not in systolic, BP were linearly related to the death risk (HR (1 mmHg reduction): 1.04, 95% CI 1.01–1.07, p = 0.006), and this was also true for CV death (HR: 1.08, 95% CI 1.03–1.12, p = 0.001). The strength of this association was not affected by further data adjustment (p ≤ 0.05). These findings suggest that independent of the formal diagnosis of orthostatic hypotension, even minor orthostatic reductions in diastolic BP bear an excess death risk in this population.