Consolidation of composite cathodes with NCM and sulfide solid-state electrolytes by hot pressing for all-solid-state Li metal batteries

Journal of Solid State Electrochemistry - In this study, hot pressing was evaluated as a method of cell fabrication to increase the energy density of next-generation all-solid-state batteries with...     

Recent advances and challenges in the recovery and purification of cellular exosomes

Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed.     

Impact of the Oxygen Defects and the Hydrogen Concentration on the Surface of Tetragonal and Monoclinic ZrO2 on the Reduction Rates of Stearic Acid on Ni/ZrO2

The role of the specific physicochemical properties of ZrO₂ phases on Ni/ZrO₂ has been explored with respect to the reduction of stearic acid. Conversion on pure m‐ZrO₂ is 1.3 times more active than on t‐ZrO₂, whereas Ni/m‐ZrO₂ is three times more active than Ni/t‐ZrO₂. Although the hydrodeoxygenation of stearic acid can be catalyzed solely by Ni, the synergistic interaction between Ni and the ZrO₂ support causes the variations in the reaction rates. Adsorption of the carboxylic acid group on an oxygen vacancy of ZrO₂ and the abstraction of the α‐hydrogen atom with the elimination of the oxygen atom to produce a ketene is the key to enhance the overall rate. The hydrogenated intermediate 1‐octadecanol is in turn decarbonylated to heptadecane with identical rates on all catalysts. Decarbonylation of 1‐octadecanol is concluded to be limited by the competitive adsorption of reactants and intermediate. The substantially higher adsorption of propionic acid demonstrated by IR spectroscopy and the higher reactivity to O₂ exchange reactions with the more active catalyst indicate that the higher concentration of active oxygen defects on m‐ZrO₂ compared to t‐ZrO₂ causes the higher activity of Ni/m‐ZrO₂.     

Engineering Multifunctional Gold Decorated Dendritic Mesoporous Silica/Tantalum Oxide Nanoparticles for Intraperitoneal Tumor‐Specific Delivery

Nonspecific high‐energy radiation for treatment of metastatic ovarian cancer is limited by damage to healthy organs, which can be mitigated by the use of radiosensitizers and image‐guided radiotherapy. Gold (Au) and tantalum oxide (TaO_x) nanoparticles (NPs), by virtue of their high atomic numbers, find utility in the design of bimetallic NP systems capable of high‐contrast computed tomography (CT) imaging as well as a potential radiosensitizing effect. These two radio‐dense metals are integrated into dendritic mesoporous silica NPs (dMSNs) with radial porous channels for high surface‐area loading of therapeutic agents. This approach results in stable, monodispersed dMSNs with a uniform distribution of Au on the surface and TaO_x in the core that exhibits CT attenuation up to seven times greater than iodine or monometallic dMSNs without either TaO_x or Au. Tumor targeting is assessed in a metastatic ovarian cancer mouse model. Ex vivo micro‐CT imaging of collected tumors shows that these NPs not only accumulate at tumor sites but also penetrate inside tumor tissues. This study demonstrates that after intraperitoneal administration, rationally designed bimetallic NPs can simultaneously serve as targeted contrast agents for imaging tumors and to enhance radiation therapy in metastatic ovarian cancer.     

Crystal structures of two isostructural compounds: a second polymorph of dipotassium hydrogen citrate,K2HC6H5O7, and potassium rubidium hydrogen citrate,KRbHC6H5O7

The crystal structures of a new polymorph of dipotassium hydrogen citrate, 2K⁺·HC₆H₅O₇^2?, and potassium rubidium hydrogen citrate, K⁺·Rb⁺·HC₆H₅O₇^2?, have been solved and refined using laboratory powder X‐ray diffraction and optimized using density functional techniques. In the new polymorph of the dipotassium salt, KO₇ and KO₈ coordination polyhedra share corners and edges to form a three‐dimensional framework with channels parallel to the a axis and [111]. The hydrophobic methylene groups face each other in the channels. The un‐ionized carboxylic acid group forms a strong charge‐assisted hydrogen bond to the central ionized carboxylate group. The hydroxy group forms an intermolecular hydrogen bond to a different central carboxylate group. In the potassium rubidium salt, the K⁺ and Rb⁺ cations are disordered over two sites, in approximately 0.72:0.28 and 0.28:0.72 ratios. KO₈ and RbO₉ coordination polyhedra share corners and edges to form a three‐dimensional framework with channels parallel to the a axis. The un‐ionized carboxylic acid group forms a strong charge‐assisted hydrogen bond to an ionized carboxylate group. The hydroxy group forms an intermolecular hydrogen bond to the central carboxylate group. Density functional theory (DFT) calculations on the ordered cation structures suggest that interchange of K⁺ and Rb⁺ at the two cation sites changes the energy insignificantly.     

Supercritical fluid chromatography with photodiode array detection for pesticide analysis in papaya and avocado samples

To improve the analysis of pesticides in complex food matrices with economic importance, alternative chromatographic techniques, such as supercritical fluid chromatography, can be used. Supercritical fluid chromatography has barely been applied for pesticide analysis in food matrices. In this paper, an analytical method using supercritical fluid chromatography coupled to a photodiode array detection has been established for the first time for the quantification of pesticides in papaya and avocado. The extraction of methyl parathion, atrazine, ametryn, carbofuran, and carbaryl was performed through the quick, easy, cheap, effective, rugged, and safe methodology. The method was validated using papaya and avocado samples. For papaya, the correlation coefficient values were higher than 0.99; limits of detection and quantification ranged from 130–380 and 220–640 μg/kg, respectively; recovery values ranged from 72.8–94.6%; precision was lower than 3%. For avocado, limit of detection values were ?450 μg/kg; precision was lower than 11%; recoveries ranged from 50.0–94.2%. Method feasibility was tested for lime, banana, mango, and melon samples. Our results demonstrate that the proposed method is applicable to methyl parathion, atrazine, ametryn, and carbaryl, toxics pesticides used worldwide. The methodology presented in this work could be applicable to other fruits.