SUMMARYA reliable evaluation of crop nutritional status is crucial for supporting fertilization aiming at maximizing qualitative and quantitative aspects of production and reducing the environmental impact of cropping systems. Most of the available simulation models evaluate crop nutritional status according to the nitrogen (N) dilution law, which derives critical N concentration as a function of above-ground biomass. An alternative approach, developed during a project carried out with students of the Cropping Systems Masters course at the University of Milan, was tested and compared with existing models (N dilution law and approaches implemented in EPIC and DAISY models). The new model (MAZINGA) reproduces the effect of leaf self-shading in lowering plant N concentration (PNC) through an inverse of the fraction of radiation intercepted by the canopy. The models were tested using data collected in four rice (Oryza sativaL.) experiments carried out in Northern Italy under potential and N-limited conditions. MAZINGA was the most accurate in identifying the critical N concentration, and therefore in discriminating PNC of plants growing under N-limited and non-limited conditions, respectively. In addition, the present work proved the effectiveness of crop models when used as tools for supporting education.

Background: During coronavirus disease 2019 (COVID-19) pandemic, Helmet Continuous Positive Airway Pressure (h-CPAP) has been widely used to treat Acute Hypoxemic Respiratory Failure (AHRF). In COVID-19 patients undergoing h-CPAP a simple short peripheral catheter could be insufficient. According to the European Recommendations for Proper Indication and Use of Peripheral venous access consensus, a stable peripheral Vascular Access Device is indicated for intravenous treatment compatible with the peripheral route scheduled for more than 1 week. Objective: The aim of this prospective study was to evaluate the performance and the potential complications of superficial femoral midline catheters (SFMC) inserted in the Superficial Femoral Vein by direct Seldinger technique with peripheral tip (Arrow®, Teleflex; 20 cm length four FR single lumen and seven FR dual lumen) in AHRF COVID-19 patient. Complications were divided in early (accidental puncture of superficial femoral artery (APSFA); accidental saphenous nerve puncture (ASNP); bleeding) and late (Catheter Related Thrombosis (CRT); Catheter-Related Bloodstream Infections (CRBSI); Accidental Removal (AR); persistent withdrawal occlusion (PWO)). Methods: From 1st October 2020 to 30th June 2021 we conducted a prospective observational study in COVID-19 sub-intensive wards at Luigi Sacco Hospital (Milan). Results: Hundred seventy five SFMC (mean dwell time 11.1 ± 9.8 days) were implanted in COVID-19 patients, 107 (61.1%) during h-CPAP treatment (10.5 ± 8.9 days), the remaining 68 (38.9%) in patients with severe disease. We recorded two minor immediate/early complications (APSFA without sequelae) and no major complications. The long-term follow-up registered four CRBSI (2.3%–2.5/1000 catheters days (CD)), five CRT (2.9%: 2.6/1000 CD), 22 AR (12.6%; 11.4/1000 CD), 38 PWO (36.5%), 34 of which occurred due to fibroblastic sleeve (32.7%). Conclusions: SFMC proved to be safe, easy and time-saving. It could be implemented, after a careful benefits and risks evaluation, in particular settings such as h-CPAP, delirium, bleeding risk factors and palliative care patients.

Introduction: Venous catheters inserted in superficial femoral vein and with mid-thigh exit site have emerged as a feasible and safe technique for central or peripheral tip’s venous access, especially in agitated, delirious patients. The spread of multidrug-resistant bacterial (MDR) strains is an emerging clinical problem and more and more patients are being colonized by these types of bacteria. The aim of this study is to evaluate the incidence of central line associated bloodstream infections (CLABSI) or catheter related bloodstream infections (CRBSI) in mid-thigh catheters in patients with positive rectal swabs to evaluate the safety of this procedure and the real infection risk. Methods: In this retrospective observational study, we analyzed data on patients with mid-tight catheters inserted from May 2021 to November 2022. All surveillance rectal swabs were recorded. In addition, to collect data on CLABSI and CRBSI, the results of all blood and catheter tip cultures performed during the hospital stay were acquired. Results: Six hundred two patients were enrolled, 304 patients (50.5%) had a rectal swab; 128 (42.1%) swabs were positive for MDR. Nine CLABSI (only two in patients with a positive rectal swab) and three CRBSI were detected. No statistical difference in the absolute number of CLABSI and CRBSI and in the number of infections per 1000 catheter days emerged between the overall population and patients with positive rectal swabs (respectively p = 0.45 and p = 0.53). Similarly, no statistical difference in the number of CLABSI and CRBSI was found among patients with a negative swab and patients with a positive one (respectively p = 0.43 and p = 0.51). Conclusions: According to our data, cannulation of the superficial femoral vein represents a safe location in patients with positive rectal swabs.