Three-dimensionalization via control of laser-structuring parameters for high energy and high power lithium-ion battery under various operating conditions

Laser-structuring is an effective method to promote ion diffusion and improve the performance of lithium-ion battery(LIB)electrodes.In this work,the effects of laser structuring parameters(groove pitch and depth)on the fundamental characteristics of LIB electrode,such as interfacial area,internal resistances,material loss and electrochemical performance,are investigated,LiNi_0.5Co_0.2Mn_0.3O₂ cathodes were structured by a femtosecond laser by varying groove depth and pitch,which resulted in a material loss of 5%-14%and an increase of 140%-260%in the in terfacial area between electrode surface and electrolyte.It is shown that the importance of groove depth and pitch on the electrochemical performance(specific capacity and areal discharge capacity)of laser-structured electrode varies with current rates.Groove pitch is more im porta nt at low current rate but groove depth is at high curre nt rate.From the mapping of lithium concentration within the electrodes of varying groove depth and pitch by laser-induced breakdown spectroscopy,it is verified that the groove functions as a diffusion path for lithium ions.The ionic,electronic,and charge transfer resistances measured with symmetric and half cells showed that these internal resistances are differently affected by laser structuring parameters and the changes in porosity,ionic diffusion and electronic pathways.It is demonstrated that the laser structuring parameters for maximum electrode performance and minimum capacity loss should be determined in consideration of the main operating conditions of LIBs.     

ATP-induced focal adhesion kinase activity is negatively modulated by phospholipase D2 in PC12 cells

Extracellular ATP has been known to modulate various cellular responses including mitogenesis, secretion and morphogenic activity in neuronal cells. In the ATP-induced morphogenic activity, focal adhesion kinase(s) such as Fak have been suggested to play a critical role. Binding of ATP to its specific cell surface receptor in PC12 cells induces phospholipase D (PLD) activity. However, the role of PLD on ATP-induced Fak activation in PC12 cells remains unclear. In this study, we investigated the role of PLD on the ATP-induced Fak activation and paxillin phosphorylation using two established cell lines: wild type PLD2- and lipase-inactive mutant PLD2-inducible PC12 cells. Stimulation of cells with ATP caused PLD2 activation via classical protein kinase C activation. ATP also induced Fak activation, and paxillin phosphorylation, and were dramatically reduced by wild type PLD2 overexpression but not by lipase-inactive mutant PLD2 overexpression. When the PC12 cells were pretreated with propranolol, a specific inhibitor for phosphatidic acid phosphohydrolase resulting in the accumulation of PA, ATP-induced Fak activation and paxillin phosphorylation were also reduced. We found that inhibition of tyrosine phosphatases by pervanadate completely blocked PLD2-dependent Fak and paxillin dephosphorylation. Taken together, we suggest that PLD2 activity might play a negative role in ATP-induced Fak and paxillin phosphorylation possibly through tyrosine phosphatases.     

Temperature/pH‐Sensitive Hydrogels Prepared from Pluronic Copolymers End‐Capped with Carboxylic Acid Groups via an Oligolactide Spacer

The Pluronic F127 triblock copolymer was end‐capped by carboxyl groups using a degradable oligolactide as a spacer to confer pH‐ and thermo‐sensitive properties. With increasing chain length of the oligolactide, the temperature‐dependent sol‐gel transition curve was significantly shifted to higher concentration with concomitant narrowing of the gelation temperature range. Carboxylic acid end‐capped Pluronic also exhibited a peculiar pH‐dependent sol‐gel transition behavior. At 37 °C, sharp gel‐to‐sol and sol‐to‐gel transitions were observed around pH = 4.8 and 8.2, respectively. The pH‐dependent phase transition was caused by introduction of carboxylic acid groups at the ends of Pluronic F127.

     

Resveratrol stimulates glucose transport in C2C12 myotubes by activating AMP-activated protein kinase

trans-Resveratrol (t-RVT), a naturally occurring polyphenol found in Polygonum cuspidatum, grape, and red wine, has been reported to have anti-inflammatory, cardioprotective, and cancer chemopreventive properties. However antidiabetic effect of t-RVT has not yet been reported. In this study, we show that t-RVT increases glucose uptake in C2C12 myotubes by activating AMP-activated protein kinase (AMPK), uncovering an antidiabetic potential of t-RVT for the first time. AMPK plays a central role in the regulation of glucose and lipid metabolism, and hence it is considered a novel therapeutic target for metabolic syndrome such as type 2 diabetes. t-RVT significantly induced glucose uptake in C2C12 cells, via AMPK activation, but not a phosphatidylinositol-3 kinase (PI-3 kinase) signal pathway. The induced glucose uptake was attenuated by pretreatment with a pharmacological inhibitor for AMPK, indicating that the effect of t-RVT primarily depends on AMPK activation. However, in the presence of insulin, t-RVT also potentiated the effect of insulin on glucose uptake via AMPK activation, which led to further activation of PI-3 kinase/Akt signal pathway.     

Doubly Modified Electrodes for the Selective Determination of Dopamine in the Presence of Interfering Species

In this paper, we describe the double modification of the glassy carbon electrode surface with two polymer layers for the selective determination of dopamine. The first layer was the electropolymerized macrocyclic nickel complex acting as an electrocatalyst for the dopamine oxidation and the second layer the polyurethane benzyl L ‐glutamate (PUBLG) for screening interfering species. Hydrolyzed PUBLG (PU‐C) showed a better screening effect. Thus prepared GC/Ni(II) complex film/PU‐C electrodes exhibited improved selectivity and better performance than unmodified counterparts, with minimum passivation even in the presence of large excess of interferents. Under optimal conditions, these electrodes showed a linear response over a dopamine concentration range of 2.5×10^?7 and 3.0×10^?5 M with a correlation coefficient of 0.999 and detection limit (at S/N=3) of 8.0×10^?8 M. The recoveries of dopamine in the 5‐fold diluted human urine sample were 96.9% for 4 measurements. The rate constant for the dopamine oxidation measured by the rotating disk electrode was found to be 1.1×10^?3 cm s^?1.     

Angiotensin II-induced aortic ring constriction is mediated by phosphatidylinositol 3-kinase/L-type calcium channel signaling pathway

Angiotensin II (AngII) is a crucial hormone that affects vasoconstriction and exerts hypertrophic effects on vascular smooth muscle cells. Here, we showed that phosphatidylinositol 3-kinase-dependent calcium mobilization plays pivotal roles in AngII-induced vascular constriction. Stimulation of rat aortic vascular smooth muscle cell (RASMC)-embedded collagen gel with AngII rapidly induced contraction. AngII-induced collagen gel contraction was blocked by pretreatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor ({"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002) whereas ERK inhibitor (PD98059) was not effective. AngII-induced collagen gel contraction was significantly blocked by extracellular calcium depletion by EGTA or by nifedipine which is an L-type calcium channel blocker. In addition, AngII-induced calcium mobilization was also blocked by nifedipine and EGTA, whereas intracellular calcium store-depletion by thapsigargin was not effective. Finally, pretreatment of rat aortic ring with {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002 and nifedipine significantly reduced AngII-induced constriction. Given these results, we suggest that PI3K-dependent activation of L-type calcium channels might be involved in AngII-induced vascular constriction.     

Direct measurement of active thiol metabolite levels of clopidogrel in human plasma using tris(2‐carboxyethyl)phosphine as a reducing agent by LC–MS/MS

A simple, robust, and rapid LC–MS/MS method has been developed and validated for the simultaneous quantitation of clopidogrel and its active metabolite (AM) in human plasma. Tris(2‐carboxyethyl)phosphine (TCEP) was used as a reducing agent to detect the AM as a disulfide‐bonded complex with plasma proteins. Mixtures of TCEP and human plasma were deproteinized with acetonitrile containing 10 ng/mL of clopidogrel‐d₄ as an internal standard (IS). The mixtures were separated on a C₁₈ RP column with an isocratic mobile phase consisting of 0.1% formic acid in acetonitrile and water (90:10, v/v) at a flow rate of 0.3 mL/min. Detection and quantification were performed using ESI‐MS. The detector was operated in selected reaction‐monitoring mode at m/z 322.0→211.9 for clopidogrel, m/z 356.1→155.2 for the AM, and m/z 326.0→216.0 for the IS. The linear dynamic range for clopidogrel and its AM were 0.05–20 and 0.5–200 ng/mL, respectively, with correlation coefficients (r) greater than 0.9976. Precision, both intra‐ and interday, was less than 8.26% with an accuracy of 87.6–106%. The validated method was successfully applied to simultaneously analyze clinical samples for clopidogrel and its AM.     

Bifunctional Nanoparticles Constructed Using One‐Pot Encapsulation of a Fluorescent Polymer and Magnetic (Fe3O4) Nanoparticles in a Silica Shell

Integration of biocompatible silica with a fluorescent polymer (PDDF) and superparamagnetic iron oxide nanoparticles (Fe₃O₄) to form uniform core–shell nanostructures has the great potential to form particles for use in multimodal bioimaging applications. Core–shell nanoparticles (PDDF/Fe₃O₄@SiO₂) exhibit fluorescent and magnetic properties that are favorable for their use in magnetic separation and guiding applications, as well as optical and magnetic resonance (MR) imaging capabilities. With the biological analysis in an in vitro intracellular permeation and cytotoxicity test, chemical conjugation of the surface using folic acid (FA) molecules can provide the nanoparticles with cell‐targeting properties, localizing the nanoparticles to folate receptors (FRs) on target KB cells that over‐express the FRs.

     

Microfluidic‐Printed Microcarrier for In Vitro Expansion of Adherent Stem Cells in 3D Culture Platform

Microcarrier‐based stem cell expansion cultures can increase the dimensions of in vitro stem cell cultures from 2D to 3D. The culture handling process then becomes more efficient compared with conventional 2D cultures. However, the use of spherical plastic microcarriers complicates the monitoring of cell culture. To facilitate monitoring, transparent disc‐shaped microcarriers are manufactured using a light‐initiated microfluidic printing system and the obtained microcarriers are named as 2.5D microcarrier. The 2.5D microcarriers (diameter/height ≈ 5) enable us to use conventional monitoring tools in 2D‐based platform during the in vitro expansion on a 3D culture platform. Surface modification via a 1 h‐long poly‐dopamine (PDA) reaction can maintain the transparent nature of the microcarriers while optimizing the cell attachment. The surface marker expression and differentiation potential of the 2.5D microcarrier‐expanded stem cells reveal that the characteristics and functionalities preserved during expansion. The 2.5D microcarrier is readily integrated into an on‐bead assay to conserve reagents and permit a high number (n = 9) of repeated measurements with reliable results. These results demonstrate that the 2.5D microcarrier‐based scale‐up culture provides a valuable tool for the in vitro expansion of adherent stem cells, especially if repetitive monitoring is required.     

Loss of trace impurities during NAA of liquid reagents

The loss of trace elements during NAA of five liquid reagents, hydrofluoric acid, hydrochloric acid, nitric acid, hydrogen peroxide and deioniyed water, has been investigated using 17 radioactive tracers of⁴⁶Sc,⁵¹Cr,⁵⁴Mn,⁵⁹Fe,⁶⁰Co,⁶⁴⁵Zn,⁷⁵Se,⁸⁵Sr,⁹⁵Zr,¹¹³Sn,¹²⁴Sb,¹⁵¹Eu,¹⁶⁰Yb,¹⁷⁷Lu,¹⁸²Ta,²³³Pa. Two kinds of container quartz and polyethylene have been used for irradiation and also for preconcentration of the reagents. The containers were cleaned before use by washing-leaching-rinsing procedure. The reagents were preconcentrated by subboiling evaporation under the infrared lamp in clean bench. The loss of trace elements has been revealed to be severer for the reagents of hydrochloric acid and nitric acid in the container of quartz than for the other cases, while that is lowest for hydrogen peroxide.