Elastocaloric Properties of Polycrystalline Samples of NiMnGaCu Ferromagnetic Shape Memory Alloy under Compression: Effect of Improvement of Thermoelastic Martensitic Transformation.

Shape memory alloys (SMAs) and ferromagnetic shape memory alloys (FeSMAs) have recently attracted interest for solid state refrigeration applications. Among NiMnGa-based quaternary systems, NiMnGaCu exhibits an interesting giant magnetocaloric effect thanks to the overlapping of the temperatures related to the magnetic transition and the thermoelastic martensitic transformation (TMT); in particular, for compositions with Cu content of approximately 6 at%. In the present work, we investigated the improvement effect of TMT on the total entropy change (ΔS) in the elastocaloric performances of polycrystalline Ni50Mn18.5Cu6.5Ga25 at% alloy samples, just above room temperature. We report an extensive calorimetric and thermomechanical characterization to explore correlations between microstructural properties induced by the selected thermal treatment and elastocaloric response, aiming at providing the basis to develop more efficient materials based on this quaternary system. Both ΔT and ΔS values obtained from mechanical curves at different temperatures and strain recovery tests under fixed load vs. T were considered. Maximum values of ΔS = 55.9 J/KgK and ΔT = 4.5 K were attained with, respectively, a stress of 65 MPa and strain of 4%. The evaluation of the coefficient of performance (COP) was carried out from a cyclic test.

Appropriate solid waste management system in Quelimane (Mozambique): study and design of a small-scale center for plastic sorting with wastewater treatment.

Appropriate solid waste management (SWM) strategies are necessary to avoid severe environmental and sanitary impacts, especially in low-income countries. Such strategies are most likely to succeed whether implementing actors are supported by scientific research. In this paper, the results of a collaboration between local authorities and researchers are presented and discussed that are the assessment of waste generation in the city of Quelimane (Mozambique), integrating existing and field-collected data and the design of a small-scale center for plastic sorting to complement the SWM system of the city. The center is expected to receive about 0.3-0.4 t/day of plastic waste (5%-7% of the overall amount of plastic waste daily produced in Quelimane). As long-term sustainability represents a typical issue, simplicity of operation was a leading principle in the design of the center; moreover, the design included a treatment plant (WWTP) for generated wastewater, whose management is usually neglected in such interventions. Among others, natural wastewater treatment (constructed wetlands) has been chosen for its affordability. Noteworthy, the so-conceived WWTP appears as a novelty in the scientific literature associated with small-scale plastic sorting plants. The system is designed to treat an average flow of 6 m3/day and consisted of a septic tank followed by a subsurface flow constructed wetland. Overall, the COD (chemical oxygen demand) and TSS (total suspended solids) removal higher than 80% and 90% were estimated, respectively. Based on this work, both the center and the WWTP were successfully realized, which are waiting to become operational. In the authors' opinion, the implemented procedure could become a reference for broader investigations and surveys. Supplementary Information: The online version contains supplementary material available at 10.1007/s42768-022-00091-6.

Microstructural and Thermo-Mechanical Characterization of Cast NiTiCu20 Shape Memory Alloy.

Among NiTi-based alloys, one of the most promising and exploited alloys is NiTiCu, since the addition of Cu in substitution of Ni in the binary equiatomic NiTi has a significant influence on the martensitic transformation and the thermomechanical properties of the system. A high content of Cu improves the damping properties at the expense of phase homogeneity and workability. The present study focuses on an alloy with a high copper content, i.e., 20 at.%. For this specific composition, the correlation between the thermal treatments, microstructure, formation of secondary phases, and damping properties are investigated by several analyses. The microscopic observation, together with the compositional analysis, allowed the determination of four different phases in the alloy. Both the calorimetry and dynamic thermo mechanical measurements, which confirmed the high damping ability of the alloy, provided a characterization of the martensitic transition. Finally, the electron backscatter diffraction (EBSD) analysis detected the different crystallographic structures (i.e., cubic austenite, orthorhombic martensite, and cubic (face-centered) NiTi2) and their orientation in the different phases. Therefore, the present work aims to improve the knowledge of the role of secondary phases in the optimization of the NiTiCu20 alloy as a valuable alternative to typical alloys used for damping purposes.

Physical Characterization of Sintered NiMnGa Ferromagnetic Shape Memory Alloy.

The present work focused on the microstructural, thermal, electrical, and damping characterization of NiMnGa samples produced through a powder pressing and a sintering process; the effect of sintering times and of the starting powder size were evaluated. Moreover, an observation of the evolution of martensitic transformation typical of NiMnGa ferromagnetic shape memory alloy was conducted in comparison with the cast material behavior and in correlation with the material densification. The optimum powder size and sintering time for the process, i.e., 50 µm or lower and 72 h, were identified considering the investigated physical properties of the sintered samples in comparison to the cast material. The corresponding sample showed the best compromise between density, thermal and electrical properties, and damping and functional behaviour. In general, the outcomes of this study could be the basis of a useful tool for production processes that include a sintering step as well as being a starting point for the evaluation of an alternative low cost fabrication method of this alloy.

Alpha defensin, leukocyte esterase, C-reactive protein, and leukocyte count in synovial fluid for pre-operative diagnosis of periprosthetic infection.

Synovial fluid analysis for diagnosis of prosthetic joint infections has gained increasing interest in the recent past when markers more specific for these infections than the serum ones have been identified. Despite the important steps forward, identification of a gold standard has not yet been identified. In this study, usefulness of alpha defensin, leukocyte esterase, C-reactive protein (CRP), and white blood cells (WBCs) in synovial fluids alone and in combination for diagnosis of prosthetic joint infection was evaluated. Synovial fluids from 32 infected and 34 not infected patients were analyzed. Sensitivity, specificity, positive and negative predictive values, diagnostic accuracy, and receiver-operating characteristic (ROC) curves were calculated for each parameter. Moreover, combination of coupled variables was also evaluated by logistic regression analysis. Sensitivity of alpha defensin, CRP, leukocyte count, and leukocyte esterase were 84.4%, 87.5%, 93.7%, and 93.8%, respectively. Specificity was 91.2% for leukocyte counts, 94.1% for alpha defensin, 97.0% for CRP, and 97.1% for leukocyte esterase. Diagnostic accuracy was 89.4% for alpha defensin, 92.4% for WBC counts and CRP, and 95.5% for leukocyte esterase. No statistical differences were observed in area under the curve (AUC) of the ROC curves of alpha defensin, CRP, and leukocyte counts. Logistic regression analysis applied to a model comprising all the variables showed an AUC higher than AUC of coupled variables. In conclusion, results of this study confirm the high sensitivity and specificity of synovial leukocyte esterase for diagnosis of prosthetic joint infection, also suggesting the need to assess a panel of markers to optimize diagnosis of these infections.

Reliability of a multiplex PCR system for diagnosis of early and late prosthetic joint infections before and after broth enrichment.

Early microbiological diagnosis of prosthetic joint infection (PJI) is essential for successful antimicrobial treatment; however, culture has limited sensitivity, particularly in patients who had received antibiotic therapy, and the utility of molecular methods for diagnosing PJIs remains debated. We investigated the reliability of a multiplex PCR system for the microbiological diagnosis of early and late PJIs. Samples of periprosthetic tissues, synovial fluid, and prosthetic implants from 47 patients with early (n=13) or late (n=34) PJI were analyzed by conventional culture and with the multiplex-PCR Unyvero ITI® (U-ITI) cartridge system. Samples treated with dithiothreitol (DTT) and synovial fluids were spread directly on agar plates and inoculated into enrichment broths. The synovial fluids, DTT eluates and enrichment broths were processed according to the U-ITI protocol. When compared against culture as the reference method, U-ITI analysis of DTT eluates had a sensitivity of 34.2%; sensitivity of U-ITI analysis increased up to 81.6% when enrichment broths were analyzed. In particular, sensitivity was 44.4% for synovial fluids, and 41.7%, and 23.5% for DTT eluates from early and late infections, respectively. Sensitivity of analysis of enrichment broths was 83.3% for early infections, 82.3% for late infections and 77.8% for synovial fluids. Our findings seem to suggest that, when coupled with the use of broth culture, U-ITI analysis may allow for more rapid microbial identification than biochemical methods, while no advantages in time to detect microbial growth were observed. Improvements, particularly in sensitivity, are needed to make it more suitable for diagnosis of early and late PJIs.

Impact of climate change and water use policies on hydropower potential in the south-eastern Alpine region.

Climate change is expected to cause alterations of streamflow regimes in the Alpine region, with possible relevant consequences for several socio-economic sectors including hydropower production. The impact of climate change on water resources and hydropower production is evaluated with reference to the Noce catchment, which is located in the Southeastern Alps, Italy. Projected changes of precipitation and temperature, derived from an ensemble of 4 climate model (CM) runs for the period 2040-2070 under the SRES A1B emission scenario, have been downscaled and bias corrected before using them as climatic forcing in a hydrological model. Projections indicate an increase of the mean temperature of the catchment in the range 2-4K, depending on the climate model used. Projections of precipitation indicate an increase of annual precipitation in the range between 2% and 6% with larger changes in winter and autumn. Hydrological simulations show an increase of water yield during the period 2040-2070 with respect to 1970-2000. Furthermore, a transition from glacio-nival to nival regime is projected for the catchment. Hydrological regime is expected to change as a consequence of less winter precipitation falling as snow and anticipated melting in spring, with the runoff peak decreasing in intensity and anticipating from July to June. Changes in water availability reflect in the Technical Hydropower Potential (THP) of the catchment, with larger changes projected for the hydropower plants located at the highest altitudes. Finally, the impacts on THP of water use policies such as the introduction of prescriptions for minimum ecological flow (MEF) have been analyzed. Simulations indicate that in the lower part of the catchment reduction of the hydropower production due to MEF releases from the storage reservoirs counterbalances the benefits associated to the projected increases of inflows as foreseen by simulations driven only by climate change.

Impact of static cold storage VS hypothermic machine preservation on ischemic kidney graft: inflammatory cytokines and adhesion molecules as markers of ischemia/reperfusion tissue damage. Our preliminary results.

At the present time, deceased heart-beating donor kidney allografts are usually stored cold. Extended-criteria donor (ECD) grafts show higher sensitivity to ischemia-reperfusion damage than standard kidneys. The increasing use of marginal organs in clinical transplantation urgently requires a more effective preservation system. Pulsatile hypothermic machine perfusion has shown major advantages over static cold storage in terms of reduced organ injury during preservation and improved early graft function. This preliminary study aims to compare pulsatile hypothermic machine perfusion and static cold storage of kidney allografts, outlining differences in the levels of early inflammatory cytokines (TNF-α, IL-2 and IL-1ß) and soluble intracellular adhesion molecule (sICAM-1) in perfusion and preservation liquid.

Surgery of lymph nodes in papillary thyroid cancer.

Optimal treatment for differentiated thyroid carcinoma is controversial with respect to the extent of thyroid resection, the extent and technique of nodal dissection and use of prophylactic radioiodine treatment. Postoperative complications, such as recurrent laryngeal nerve injury and definitive hypoparathyroidism, have carried great weight in the discussion regarding how radical the surgical treatment should be. The discussion of whether total thyroidectomy or lesser procedures should be the treatment for thyroid carcinomas has been protracted. Now, reasonable agreement exists that total thyroidectomy is the best treatment and the focus of the discussion has moved to the treatment of lymph nodes. At the time of diagnosis, node metastases are a common finding in patients with differentiated thyroid cancer, in particular papillary carcinoma. The argument supporting a radical approach to lymph node excision is that the presence of node metastases increases the recurrence rate. Advocates for the conservative approach believe that little association exists between node metastases and death from thyroid carcinoma. This paper reviews relevant medical literature published in the English language on surgery of lymph nodes in differentiated thyroid cancer with well-controlled trials. Searches were last updated in June 2006.