RESUMEN

This study explores a strategy to mitigate capacity fading in secondary batteries, which is primarily attributed to side reactions caused by residual Li impurities (LiOH or Li2CO3) on the surface of Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) layered cathode materials. By applying a 1.5 wt% Co3(PO4)2 coating, we successfully formed a thin and stable LiF cathode-electrolyte interface (CEI) layer, which resulted in decreased battery resistance and enhanced diffusion of Li+ ions within the electrolyte. This coating significantly improved the interface stability of NCM811, leading to superior battery performance. Specifically, the discharge capacity of uncoated NCM811 was 190 mA h g-1 at a charge of 4.3 V and a rate of 0.1C, whereas the 1.5Co3(PO4)2/NCM811 exhibited an increased capacity of 213 mA h g-1. Furthermore, the Co3(PO4)2 coating effectively reduced the levels of LiOH and Li2CO3 on the NCM811 surface to only 0.1 %, thereby minimizing adverse side reactions with the electrolyte salt (LiPF6), cation mixing between Ni2+ and Li+, and defects at the NCM811 interface. As a result, battery lifespan was significantly extended. This study presents a robust approach for enhancing battery stability and performance by efficiently reducing residual Li+ ions on the surface of NCM811 through strategic Co3(PO4)2 coating.

RESUMEN

Worldwide regulatory frameworks for the assessment and remediation of contaminated soils have moved towards a risk-based approach, taking contaminant bioavailability into consideration. However, there is much debate on the precise definition of bioavailability and on the standardization of methods for the measurement of bioavailability so that it can be reliably applied as a tool for risk assessment. Therefore, in this paper, we reviewed the existing definitions of heavy metal bioavailability in relation to plant uptake (phytoavailability), in order to better understand both the conceptual and operational aspects of bioavailability. The related concepts of specific and non-specific adsorption, as well as complex formation and organic ligand affinity were also intensively discussed to explain the variations of heavy metal solubility and mobility in soils. Further, the most frequently used methods to measure bioavailable metal soil fractions based on both chemical extractions and mechanistic geochemical models were reviewed. For relatively highly mobile metals (Cd, Ni, and Zn), a neutral salt solution such as 0.01 M CaCl2 or 1 M NH4NO3 was recommended, whereas a strong acid or chelating solution such as 0.43 M HNO3 or 0.05 M DTPA was recommended for strongly soil-adsorbed and less mobile metals (Cu, Cr, and Pb). While methods which assessed the free metal ion activity in the pore water such as DGT and DMT or WHAM/Model VI, NICA-Donnan model, and TBLM are advantageous for providing a more direct measure of bioavailability, few of these models have to date been properly validated.

Asunto(s)

RESUMEN

Subungual atypical fibroxanthoma is a rare mesenchymal skin tumor of intermediate malignancy. It classically presents as a relatively nondescript, erythematous nodule; it may ulcerate and bleed, but pain and pruritus are uncommon. In the differential diagnoses of subungual tumors, glomus tumor, soft tissue chondroma, keratoacanthoma, hemangioma, lobular capillary hemangioma, epidermal and mucoid cysts, squamous cell carcinoma, and malignant melanoma have been suggested. But atypical fibroxanthoma has not been included in the differential diagnoses. We report a case that occurred in a 56-year-old man with subungual atypical fibroxanthoma mimicking malignant soft tissue tumor in the right fifth toe.

Asunto(s)

RESUMEN

This study employed thermogravimetric analysis (TGA) and analytical Py-GC/MS in order to examine the catalytic effect of main inorganic metals (K, Mg and Ca) on the thermal degradation and the formation of pyrolytic products in lignocellulosic biomass. In addition, potential mechanisms of the primary pyrolysis in presence of the inorganic metals were derived. TG analysis showed that when potassium content increased in the biomass, char formation increased from 10.5 wt.% to 19.6 wt.% at 550 °C, and temperatures at which the maximum degradation rate was achieved shifted from 367 °C to 333 °C. With increasing magnesium content, the maximum degradation rate increased from 1.21 wt.%/°C to 1.43 wt.%/°C. Analytical Py-GC/MS revealed that potassium had a distinguished catalytic effect promoting the formation of low molecular weight compounds and suppressing the formation of levoglucosan. An increase in the yield of C6 and C2C6 lignin derivatives with increasing potassium content was also observed.

Asunto(s)

RESUMEN

Poplar wood flour (Populous albaglandulosa) was treated with sub- and super-critical water (subcritical: 325, 350°C; super-critical: 380, 400, 425°C) for 60s at 220 ± 10 atm. Hydrochloric acid (0.05%v/v) was added to samples as acidic catalyst. The final products were separated into water soluble fraction and undegraded solids. The yields of undegraded solids were thoroughly dependent on temperature severity and mainly composed of lignin fragments. Average molecular weights of the lignins were between 1500 and 4400 Da, which was only 1/3-1/8-fold of poplar milled wood lignin (13,250 Da). DFRC (Derivatization Followed by Reductive Cleavage) analysis revealed that C6C3 phenols (coniferyl and sinapyl alcohol) were rarely detected in the lignins, indicating occurrence of two probable lignin reactions during SCW hydrolysis: lignin fragmentation via splitting of ß-O-4 linkage and loss of propane side chains. These results were also confirmed by (1)H and (13)C NMR spectroscopic analysis.

Asunto(s)

RESUMEN

Supratentorial cortical ependymoma is a rare clinical entity where ependymoma occurring in the cortex without any connection to the ventricular system since ependymoma usually arises from the lining of the ventricular system or central canal of spinal cord. There have been 14 such cases reported in the literature.We report the first case of a supratentorial extraaxial cortical anaplastic ependymoma with minimal cortical attachment in a 17-years-old girl, presented with headache and complex partial seizure. Histological features of anaplasia including numerous mitoses, necrosis and high Ki-67 lead to postoperative adjuvant radiation therapy although gross total resection was achieved.

Asunto(s)