Unified traction and battery charging systems for electric vehicles: a sustainability perspective

This paper presents an analysis of unified traction and battery charging systems for electric vehicles (EVs), both in terms of operation modes and in terms of implementation cost, when compared to dedicated solutions that perform the same operation modes. Regarding the connection of the EV battery charging system with the power grid, four operation modes are analyzed: (1) Grid–to–Vehicle (G2V); (2) Vehicle–to–Grid (V2G); (3) Vehicle–to–Home (V2H); and (4) Vehicle–for–Grid (V4G). With an EV unified system, each of these operation modes can be used in single–phase and three–phase power grids. Furthermore, a cost estimation is performed for an EV unified system and for dedicated systems that can perform the same functionalities, in order to prove the benefits of the EV unified approach. The cost estimation comprises two power levels, namely 6 kW, single–phase, related to domestic installations, and 50 kW, three–phase, related to industrial installations. The relevance of unified traction and battery charging systems for EVs is proven for single–phase and three–phase power grids.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2019. This work has been supported by the FCT Project DAIPESEV PTDC/EEI-EEE/30382/2017, and by the FCT Project new ERA4GRIDs PTDC/EEI-EEE/30283/2017

Optimization of aqueous enzyme-assisted extraction of rosmarinic acid from rosemary (Rosmarinus officinalis L.) leaves and the antioxidant activity of the extract

Rosemary (Rosmarinus officinalis L.) is a potential source of rosmarinic acid (RA). This study aimed to develop a novel aqueous enzymatic approach for extracting RA from rosemary leaves and evaluate the antioxidant activity of the RA-rich extract. The ability of several enzymes to release RA from plant tissues was investigated. Among the examined enzymes, cellulase A exhibited the highest extraction efficiency. Subsequently, aqueous cellulase A-assisted extraction was optimized. The optimal extraction conditions were as follows: an extraction time of 4.63 hr, a water-to-sample ratio of 28.69 ml/g, an enzyme concentration of 2.56%, and a temperature of 36.6°C, with the maximum RA content of 13.97 mg/g. The RA-rich extract exhibited potent antioxidant activity against the 2,2-diphenyl-1-picrylhydrazyl radical with an IC50 value of 532.01 μg/ml. Aqueous cellulase-assisted extraction is a green approach for RA extraction from rosemary leaves. Furthermore, the rosemary leaf extract is a promising antioxidant agent for future use. Practical applications: RA is a potent antioxidant and is widely applied in the food and pharmaceutical industries. This study developed a new method involving the use of enzyme for ecofriendly extracting RA from rosemary leaves. The results indicated that the RA-rich extract is a potential antioxidant agent for future nutraceutical and pharmaceutical applications and the aqueous cellulase-assisted extraction is a practical and green process for RA extraction from rosemary leaves

Cardio-haemodynamic assessment and venous lactate in severe dengue: Relationship with recurrent shock and respiratory distress

BACKGROUND: Dengue can cause plasma leakage that may lead to dengue shock syndrome (DSS). In approximately 30% of DSS cases, recurrent episodes of shock occur. These patients have a higher risk of fluid overload, respiratory distress and poor outcomes. We investigated the association of echocardiographically-derived cardiac function and intravascular volume parameters plus lactate levels, with the outcomes of recurrent shock and respiratory distress in severe dengue. METHODS/PRINCIPLE FINDINGS: We performed a prospective observational study in Paediatric and adult ICU, at the Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam. Patients with dengue were enrolled within 12 hours of admission to paediatric or adult ICU. A haemodynamic assessment and portable echocardiograms were carried out daily for 5 days from enrolment and all interventions recorded. 102 patients were enrolled; 22 patients did not develop DSS, 48 had a single episode of shock and 32 had recurrent shock. Patients with recurrent shock had a higher enrolment pulse than those with 1 episode or no shock (median: 114 vs. 100 vs. 100 b/min, P = 0.002), significantly lower Stroke Volume Index (SVI), (median: 21.6 vs. 22.8 vs. 26.8mls/m2, P<0.001) and higher lactate levels (4.2 vs. 2.9 vs. 2.2 mmol/l, P = 0.001). Higher SVI and worse left ventricular function (higher Left Myocardial Performance Index) on study days 3-5 was associated with the secondary endpoint of respiratory distress. There was an association between the total IV fluid administered during the ICU admission and respiratory distress (OR: 1.03, 95% CI 1.01-1.06, P = 0.001). Admission lactate levels predicted patients who subsequently developed recurrent shock (P = 0.004), and correlated positively with the total IV fluid volume received (rho: 0.323, P = 0.001) and also with admission ALT (rho: 0.764, P<0.001) and AST (rho: 0.773, P<0.001). CONCLUSIONS/SIGNIFICANCE: Echo-derived intravascular volume assessment and venous lactate levels can help identify dengue patients at high risk of recurrent shock and respiratory distress in ICU. These findings may serve to, not only assist in the management of DSS patients, but also these haemodynamic endpoints could be used in future dengue fluid intervention trials