A study of the strengthening mechanisms in the novel precipitation hardening KEYLOS® 2001 Steel

KeyLos ® 2001 is a new precipitation-hardening steel especially developed for plastic moulds. In this study the precipitation stage of KeyLos ® 2001 steel has been investigated and compared to the results obtained with 17-4 PH steel. Precipitation-hardening has been carried out at three different temperatures and the stages of hardening and overageing have been studied in order to clarify the hardening mechanisms. It has been found that hardening and softening mechanism during the precipitation-hardening treatment occur at higher temperatures and in correspondence with more prolonged treatment times than those typical for the best known 17-4 PH steel; hardness is then expected to remain stable also for very extended mould lives. Microstructural investigations by means of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) have also been carried out and the microstructural parameters responsible for the hardening and overageing have been pointed out

Functional evaluation protocol

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On the crack path of rolling contact fatigue cracks in a railway wheel steel

The objective of the present paper is to give some preliminary results obtained in the frame of a more wide investigation on the rolling contact fatigue (RCF) behavior of a railway wheel steel. The effect of different test parameters on the RCF fatigue strength of the railway wheel steel was evaluated. RCF tests were conducted using two cylindrical contact specimens under different Po/k ratio (where Po is the maximum Hertzian pressure, k is the yield stress in shear of the material), under dry contact conditions or with water lubrication, and at varying slip ratio. In the present study crack initiation location and crack growth direction were carefully investigated; microscopic examination showed that the cracks were initiated at the surface, propagated obliquely in the depth direction and then occasionally branched into two directions. Usually multiple cracks are initiated, at the rolling contact surface, caused by the accumulation of shear deformation due to repeated rolling–sliding contact loading. Subsequent crack growth has been found to occur along specific sloped directions. The influence of Po/k ratio, dry or wet contact, and slip ratio on crack slope angle to the radial direction and the depths at which slope changes occur has been investigated. Observed crack slopes and slope change position have been discussed according to crack path prediction criteria in the literature

Authentication of European sea bass according to production method and geographical origin by light stable isotope ratio and rare earth elements analyses combined with chemometrics

In this work, stable isotope ratio (SIR) and rare earth elements (REEs) analyses, combined with multivariate data elaboration, were used to explore the possibility to authenticate European sea bass (Dicentrarchus labrax L.) according to: i) production method (wild or farmed specimens); ii) geographical origin (Western, Central or Eastern Mediterranean Sea). The dataset under investigation included a total of 144 wild and farmed specimens coming from 17 different European areas located in the Mediterranean Sea basin. Samples were subjected to SIR analysis (carbon and nitrogen) and REEs analysis (lanthanum, europium, holmium, erbium, lutetium, and terbium). Then, Analytical data were handled by Principal Component Analysis (PCA) and then by Orthogonal Partial Last Square Discriminant Analysis (OPLS-DA), to obtain functional classification models to qualitatively discriminate sea bass according to the conditions under study. OPLSDA models provided good correct classification rate both for production method and geographical origin. It was confirmed that chemometric elaboration of data obtained from SIR and REEs analyses can be a suitable tool for an accurate authentication of European sea bass

Developing a risk assessment score for patients with cancer during the coronavirus disease 2019 pandemic

The novel coronavirus (CoV) pandemic is a serious threat for patients with cancer, who have an immunocompromised status and are considered at high risk of infections. Data on the novel CoV respiratory disease (coronavirus disease 2019 [COVID-19]) in patients with cancer are still limited. Unlike other common viruses, CoVs have not been shown to cause a more severe disease in immunocompromised subjects. Along with direct viral pathogenicity, in some individuals, CoV infection triggers an uncontrolled aberrant inflammatory response, leading to lung tissue damage. In patients with cancer treated with immunotherapy (e.g. immune checkpoint inhibitors), COVID-19 may therefore represent a serious threat. After a thorough review of the literature on CoV pathogenesis and cancer, we selected several shared features to define which patients can be considered at higher risk of COVID-19. We combined these clinical and laboratory variables, with the aim of developing a score to weight the risk of COVID-19 in patients with cancer

Advances in troubleshooting fish and seafood authentication by inorganic elemental composition

The demand for fish and seafood is growing worldwide. Meanwhile, problems related to the integrity and safety of the fishery sector are increasing, leading legislators, producers, and consumers to search for ways to effectively protect themselves from fraud and health hazards related to fish consumption. What is urgently required now is the availability of reliable, truthful, and reproducible methods assuring the correspondence between the real nature of the product and label declarations accompanying the same product during its market life. The evaluation of the inorganic composition of fish and seafood appears to be one of the most promising strategies to be exploited in the near future to assist routine and official monitoring operations along the supply chain. The present review article focuses on exploring the latest scientific achievements of using the multi-elemental composition of fish and seafood as an imprint of their authenticity and traceability, especially with regards to the geographical origin. The scientific literature of the last 10 years focusing on the analytical determination and statistical elaboration of elemental data (alone or in combination with methodologies targeting other compounds) to verify the identity of fishery products is summarized and discussed

SUSCEPTIBILITY OF Listeria monocytogenes STRAINS ISOLATED FROM FOOD TO ANTIMICROBIAL AGENTS

The objective of this study was to evaluate the susceptibility of 40 L. monocytogenes strains isolated from seafood and processing environments to 19 antibiotics currently used in veterinary and human therapy. Susceptibility tests were performed by the automated system VITEK2. Apart from Penicillin, Ampicillin and Trimethoprim-Sulfamethoxazole, for which clinical breakpoint for Listeria susceptibility testing are defined according to the Clinical and Laboratory Standard Institute (CLSI), in the present study the CLSI criteria for staphylococci were applied. This study shows that isolated L. monocytogenes strains are susceptible to the antibiotics commonly used in veterinary and human listeriosis treatment. Very few strains (7,5%) showed a resistance behaviour towards Oxacillin, whereas a variable pattern was showed for Ciprofloxacin and Moxifloxacin. Moreover, an increase in tetracycline resistance, reported by several authors, can not be confirmed in this study, probably due to the different sources of strains isolation. At last, the VITEK2 system represents a rapid and easy-to-use means for antimicrobial susceptibility test of Listeria monocytogenes. In conclusion, because of the increase of antimicrobial resistance showed by L. monocytogenes, a continuous surveillance of emerging antimicrobial resistance among this pathogen is important to ensure effective treatment of human listeriosis. These data can be used for improve background data on antibiotic resistance of strains isolated from food and food environment, even considering the lack of clinical breakpoint provided by the CLSI