Rational Design of Ruddlesden-Popper Perovskite Ferrites as Air Electrode for Highly Active and Durable Reversible Protonic Ceramic Cells

Reversible protonic ceramic cells(RePCCs)hold promise for efficient energy storage,but their practicality is hindered by a lack of high-performance air electrode materials.Ruddlesden-Popper perovskite Sr_(3)Fe_(2)O_(7−δ)(SF)exhibits superior proton uptake and rapid ionic conduction,boosting activity.However,excessive proton uptake during RePCC operation degrades SF’s crystal structure,impacting durability.This study introduces a novel A/B-sites co-substitution strategy for modifying air electrodes,incorporating Sr-deficiency and Nb-substitution to create Sr_(2.8)Fe_(1.8)Nb_(0.2)O_(7−δ)(D-SFN).Nb stabilizes SF’s crystal,curbing excessive phase formation,and Sr-deficiency boosts oxygen vacancy concentration,optimizing oxygen transport.The D-SFN electrode demonstrates outstanding activity and durability,achieving a peak power density of 596 mW cm^(−2)in fuel cell mode and a current density of−1.19 A cm^(−2)in electrolysis mode at 1.3 V,650℃,with excellent cycling durability.This approach holds the potential for advancing robust and efficient air electrodes in RePCCs for renewable energy storage.

High performance and stability of double perovskite-type oxide NdBa0.5Ca0.5Co1.5Fe0.5O5+δas an oxygen electrode for reversible solid oxide electrochemical cell

In this study,we successfully synthesized double perovskite-type oxide NdBa0.5Ca0.5Co1.5Fe0.5O5+δ(NBCCF)using a conventional wet chemical method as the oxygen electrode for reversible solid oxide electrochemical cells(RSOCs).The polarization resistance(Rp)of the composite electrode NBCCFGd0.1Ce0.9O2(GDC)is only 0.079Ωcm^2 at 800℃under air.The single cell based on NBCCF-GDC electrode displays a peak power density of 0.941 W/cm^2 in fuel cell mode and a low Rp value of 0.134Ωcm^2.In electrolysis cell mode,the cell displays an outstanding oxygen evolution reaction(OER)activity and shows current density as high as 0.92 A/cm^2 with 50 vol%AH(Absolute Humidity)at 800℃and applied voltage of 1.3 V.Most importantly,the cell exhibits admirable durability of 60 h both in electrolysis mode and fuel cell mode with distinguished reversibility.All these results suggest that NBCCF is a promising candidate electrode for RSOC.

Double Layer Composite Electrode Strategy for Efficient Perovskite Solar Cells with Excellent Reverse-Bias Stability

Perovskite solar cells(PSCs)have become the represent-atives of next generation of photovoltaics;nevertheless,their stability is insufficient for large scale deployment,particularly the reverse bias stability.Here,we propose a transparent conducting oxide(TCO)and low-cost metal composite electrode to improve the stability of PSCs without sacrificing the efficiency.The TCO can block ion migrations and chemical reactions between the metal and perovskite,while the metal greatly enhances the conductivity of the composite electrode.As a result,composite electrode-PSCs achieved a power conversion efficiency(PCE)of 23.7%(certified 23.2%)and exhibited excellent stability,maintaining 95%of the initial PCE when applying a reverse bias of 4.0 V for 60 s and over 92%of the initial PCE after 1000 h continuous light soaking.This composite electrode strategy can be extended to different combinations of TCOs and metals.It opens a new avenue for improving the stability of PSCs.

Electrochemical performance and stability of Sr-doped LaMnO_(3)-infiltrated yttria stabilized zirconia oxygen electrode for reversible solid oxide fuel cells

Porous Sr-doped lanthanum manganite–yttria stabilized zirconia(LSM–YSZ)oxygen electrode is prepared by an infiltration process for a reversible solid oxide fuel cell(RSOFC).X-ray diffraction and SEM analysis display that perovskite phase LSM submicro particles are evenly distributed in the porous YSZ matrix.Polarization curves and electrochemical impedance spectra are conducted for the RSOFC at 800 and 850C under both SOFC and SOEC modes.At 850℃,the single cell has the maximum power density of~726 mW/cm^(2)under SOFC mode,and electrolysis voltage of 1.35 V at 1 A/cm^(2)under SOEC mode.Fuel cell/water electrolysis cycle shows the cell has good performance stability during 6 cycles,which exhibits the LSM–YSZ oxygen electrode has high electrochemical performance and good stability.The results suggest that netw ork-like LSM–YSZ electrode made by infiltration process could be a promising oxygen electrode for high temperature RSOFCs.

High-Entropy Perovskite Oxide: A New Opportunity for Developing Highly Active and Durable Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

Reversible proton ceramic electrochemical cell(R-PCEC)is regarded as the most promising energy conversion device,which can realize efficient mutual conversion of electrical and chemical energy and to solve the problem of large-scale energy storage.However,the development of robust electrodes with high catalytic activity is the main bottleneck for the commercialization of R-PCECs.Here,a novel type of high-entropy perovskite oxide consisting of six equimolar metals in the A-site,Pr_(1/6)La_(1/6)Nd_(1/6)Ba_(1/6)Sr_(1/6)Ca_(1/6)CoO_(3−δ)(PLN-BSCC),is reported as a high-performance bifunctional air electrode for R-PCEC.By harnessing the unique functionalities of multiple ele-ments,high-entropy perovskite oxide can be anticipated to accelerate reaction rates in both fuel cell and electrolysis modes.Especially,an R-PCEC utilizing the PLNBSCC air electrode achieves exceptional electrochemical performances,demonstrating a peak power density of 1.21 W cm^(−2)for the fuel cell,while simultaneously obtaining an astonishing current density of−1.95 A cm^(−2)at an electrolysis voltage of 1.3 V and a temperature of 600℃.The significantly enhanced electrochemical performance and durability of the PLNBSCC air electrode is attributed mainly to the high electrons/ions conductivity,fast hydration reactivity and high configurational entropy.This research explores to a new avenue to develop optimally active and stable air electrodes for R-PCECs.

Progress on direct assembly approach for in situ fabrication of electrodes of reversible solid oxide cells

Reversible solid oxide cells(SOCs)are very efficient and clean for storage and regeneration of renewable electrical energy by switching between electrolysis and fuel cell modes.One of the most critical factors governing the efficiency and durability of SOCs technology is the stability of the interface between oxygen electrode and electrolyte,which is conventionally formed by sintering at a high temperature of~1000–1250℃,and which suffers from delamination problem,particularly for reversibly operated SOCs.On the other hand,our recent studies have shown that the electrode/electrolyte interface can be in situ formed by a direct assembly approach under the electrochemical polarization conditions at 800℃and lower.The direct assembly approach provides opportunities for significantly simplifying the cell fabrication procedures without the doped ceria barrier layer,enabling the utilization of a variety of high-performance oxygen electrode materials on barrier layer–free yttria-stabilized zirconia(YSZ)electrolyte.Most importantly,the in situ polarization induced interface shows a promising potential as highly active and durable interface for reversible SOCs.The objective of this progress report is to take an overview of the origin and research progress of in situ fabrication of oxygen electrodes based on the direct assembly approach.The prospect of direct assembly approach in the development of effective SOCs and in the fundamental studies of electrode/electrolyte interface reactions is discussed.

Reversible and irreversible heat generation of NCA/Si–C pouch cell during electrochemical energy-storage process

To meet the requirements of electronic vehicles(EVs) and hybrid electric vehicles(HEVs),the high energy density Li Ni_(0.8) Co_(0.15) Al_(0.05) O_2(NCA) cathode and Si–C anode have attracted more attention.Here we report the thermal behaviors of NCA/Si–C pouch cell during the charge/discharge processes at different current densities.The total heat generations are derived from the surface temperature change during electrochemical Li+insertion/extraction in adiabatic surrounding.The reversible heat is determined by the entropic coefficients,which are related with open-circuit voltage at different temperatures; while the irreversible heat is determined by the internal resistance,which can be obtained via V–I characteristic,electrochemical impedance spectroscopy and hybrid pulse power characterization(HPPC).During the electrochemical process,the reversible heat contributes less than 10% to total heat generation; and the heat generated in charge process is less than that in discharge process.The results of thermal behaviors analyses are conducive to understanding the safety management and paving the way for building a reliable thermal model of high energy density lithium ion battery.

Demonstration of reversible retinal ganglion cell dysfunction in inflammatory optic neuropathies utilizing pattern electroretinography

Dear Editor,I am Dr.Austin Bach from Larkin Community Hospital in South Miami,Florida,USA.I am writing to you to present three cases of inflammatory optic neuritis that was followed to resolution using pattern electroretinography（PERG）.

Pd-La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)composite as active and stable oxygen electrode for reversible solid oxide cells

To promote the electrocatalytic activity and stability of traditional(a_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)oxygen electrodes in reversible solid oxide cells(RSOCs),conventional physical mixed method was used to prepare the Pd-LSCF composite oxygen electrode.The cell with Pd-LSCF|GDC|YSZ|Ni-YSZ configuration shows perfect electrochemical performance in both solid oxide fuel cell(SOFC)mode and solid oxide electrolysis cell(SOEC)mode.In the SOFC mode,the cell achieves a power density of 1.73 W/cm^(2)at800℃higher than that of the LSCF oxygen electrode with 1.38 W/cm^(2).In the SOEC mode,the current density at 1.5 V is 1.67 A/cm^(2)at 800℃under 50 vol%steam concentration.Moreover,the reversibility and stability of the RSOCs were tested during 192 h long-term reversible operation.The degradation rate of the cell is only 2.2%/100 h and 2.5%/100 h in the SOEC and the SOFC modes,respectively.These results confirm that compositing Pd with the LSCF oxygen electrode can considerably boost the electrochemical performance of LSCF electrode in RSOCs field.

High-entropy perovskite oxide BaCo_(0.2)Fe_(0.2)Zr_(0.2)Sn_(0.2)Pr_(0.2)O_(3-δ) with triple conduction for the air electrode of reversible protonic ceramic cells

Reversible protonic ceramic cells(RPCCs) show great potential as new-generation energy conversion and storage devices. However, the mature development of RPCCs is seriously hindered by the inactivity and poor stability of air electrodes exposed to concentrated vapor under operating conditions. Herein, we report a high-entropy air electrode with the composition BaCo_(0.2)Fe_(0.2)Zr_(0.2)Sn_(0.2)Pr_(0.2)O_(3-δ)(BCFZSP), which shows integrated electronic, protonic and oxygenic conduction in a single perovskite phase and excellent structural stability in concentrated steam. Such triple conduction can spread the electrochemically active sites of the air electrode to the overall electrode surface, thus optimizing the kinetics of the oxygen reduction and evolution reactions(0.448 Ω cm^(2) of polarization resistance at 550℃). As-prepared RPCCs with a BCFZSP air electrode at 600℃ achieved a peak power density of 0.68 W/cm^(2) in fuel-cell mode and a current density of 0.92 A/cm^(2) under a 1.3 V applied voltage in electrolysis mode. More importantly, the RPCCs demonstrate an encouragingly high stability during 120 h of reversible switching between the fuelcell and electrolysis modes. Given their excellent performance, high-entropy perovskites can be promising electrode materials for RPCCs.

Transplantation of human telomerase reverse transcriptase gene-transfected Schwann cells for repairing spinal cord injury

Transfection of the human telomerase reverse transcriptase（h TERT）gene has been shown to increase cell proliferation and enhance tissue repair.In the present study,h TERT was transfected into rat Schwann cells.A rat model of acute spinal cord injury was established by the modified free-falling method.Retrovirus PLXSN was injected at the site of spinal cord injury as a vector to mediate h TERT gene-transfected Schwann cells（1×10^（10）/L;10μL）or Schwann cells（1×10^（10）/L;10μL）without h TERT gene transfection.Between 1 and 4 weeks after model establishment,motor function of the lower limb improved in the h TERT-transfected group compared with the group with non-transfected Schwann cells.Terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling and reverse transcription-polymerase chain reaction results revealed that the number of apoptotic cells,and gene expression of aquaporin 4/9 and matrix metalloproteinase 9/2decreased at the site of injury in both groups;however,the effect improved in the h TERT-transfected group compared with the Schwann cells without h TERT transfection group.Hematoxylin and eosin staining,PKH26 fluorescent labeling,and electrophysiological testing demonstrated that compared with the non-transfected group,spinal cord cavity and motor and sensory evoked potential latencies were reduced,while the number of PKH26-positive cells and the motor and sensory evoked potential amplitude increased at the site of injury in the h TERT-transfected group.These findings suggest that transplantation of h TERT gene-transfected Schwann cells repairs the structure and function of the injured spinal cord.

Inhibition of telomerase with human telomerase reverse transcriptase antisense increases the sensitivity of tumor necrosis factor-α-induced apoptosis in prostate cancer cells

Aim： To investigate the effect of inhibition of telomerase with human telomerase reverse transcriptase （hTERT） antisense on tumor necrosis factor-α （TNF-α-induced apoptosis in prostate cancer cells （PC3）. Methods： Antisense phosphorothioate oligodeoxynucleotide （AS PS-ODN） was synthesized and purified. Telomerase activity was measured using the telomeric repeat amplification protocol （TRAP） and polymerase chain reaction enzyme-linked immunoassay （PCR-ELISA）. hTERT mRNA was measured by reverse transcription PCR （RT-PCR） assay and gel-image system, hTERT protein was detected by immunochemistry and flow cytometry. Cell viability was detected by 3-（4, 5-dimethylthiazol-2-yl）-2,5-Diphenyltetrazolium （MTT） assay. Cell apoptosis was observed by morphological method and determined by flow cytometry. Results： The telomerase activity decreased with time after hTERT AS PS-ODN treatment. The levels of hTERT mRNA decreased with time after hTERT AS PS-ODN treatment, which appeared before the decline of the telomerase activity. The percentage of positive cells of hTERT protein declined with time after hTERT AS PS-ODN treatment, which appeared after the decline of hTERT mRNA. There was no difference in telomerase activity, hTERT mRNA and protein levels between hTERT sense phosphorothioate oligodeoxynucleotide （S PS-ODN） and the control group. The cell viability decreased with time after hTERT AS PS-ODN combined with TNF-α treatment. The percentage of apoptosis increased with time after hTERT AS PS-ODN combined with TNF-α treatment. There was no difference in cell viability and the percentage of apoptosis between hTERT S PS-ODN and the control group. Conclusion： hTERT AS PS-ODN can significantly inhibit telomerase activity by downregulating the hTERT mRNA and protein expression, and inhibition of telomerase with hTERT antisense can enhance TNF-α- induced apoptosis of PC3 cells.

Reversing multiple age-related pathologies by controlling the senescence-associated secretory phenotype of stem cells

Regenerative medicine by cell transplantation is a novel therapy for treating end-stage organ failure and tissue damage. Cell-based therapy based on the transplantation of neural stem/progenitor cells （NSPCs） represents an attractive strategy for the treatment of neurodegenerative diseases, but obtaining large numbers of these cells is difficult and their differentiation potential is strictly restricted in a spatiotemporally-regulated manner during central nervous system （CNS） development. Therefore, embryonic stem cells and induced pluripotent stem cells represent an attractive alternative for cell-transplantation therapy in regenerative medicine.

A novel single event upset reversal in 40-nm bulk CMOS 6T SRAM cells

In advanced technologies, single event upset reversal(SEUR) due to charge sharing can make the upset state of SRAM cells recover to their initial state, which can reduce the soft error for SRAMs in radiation environments. By using the full 3D TCAD simulations, this paper presents a new kind of SEUR triggered by the charge collection of the Off-PMOS and the delayed charge collection of the On-NMOS in commercial 40-nm 6 T SRAM cells. The simulation results show that the proposed SEUR can not occur at normal incidence,but can present easily at angular incidence. It is also found that the width of SET induced by this SEUR remains the same after linear energy transfer(LET) increases to a certain value. In addition, through analyzing the effect of the spacing, the adjacent transistors, the drain area, and some other dependent parameters on this new kind of SEUR, some methods are proposed to strengthen the recovery ability of SRAM cells.

Multidrug Resistance P-glycoprotein Function of Bone Marrow Hematopoietic Cells and the ReversalAgent Effect

The multidrug resistance P-glycoprotein (P-gp) expression and func-tion in hematopoietic stem/progenitor cells were studied to investigate whether the inhibition of hematopoietic cell P-gp function by multidrug resistance reversal agent increases the cytotoxicity of chemotherapy drugs on the hematopoietic cells.The expression of P-gp on the surface of CD cells from healthy human marrow was examined by flow cytometry. The multidrug resistance reversal agent MS-209 was used to measure the effects of MS-209 on the Rhodamin-123 uptaking o fCD hematopoietic cells. By using methylcellulose semi-solid culture, normal human granulocyte-macrophage clonal formation unit (CFU-GM) was cultured. The changes in CFU-GM inhibitory rate caused by daunorubicin were determined in the presence or absence of MS-2O9. The results showed that the P-gp expression rate of bone marrow CDL cells was 13. 3 %. MS-209 obviously increased the Rhodamin-123 uptake of CD positive cells. The mean inhibitory rate of daunorubicin for CFU-GM was 29. 6 %, but it was increased to 43. 3 % in the presence of MS-209 with the difference being significant (P< 0. 05). It was concluded that hematopoietic cells expressed P-gp protein and possessed active function- MS-209could inhibit the membrane efflux pump and increase the cytotoxicity of chemotherapy drugs to the clonal growth of hematopoeitic stem cells, suggesting the side effects of these drugs on the hematopoietic system should be taken into consideration in the clinical use.

Evaluation of Small Interfering RNA Delivery into Cells by Reverse Transfection in Suspension with Cationic Liposomes

Successful gene silencing by small interfering RNA (siRNA) requires efficient uptake of siRNA into targeted cells. For in vitro transfection of siRNA using cationic liposomes, two types of transfection method are currently being used: conventional (forward;Fw) and reverse (Rev) transfections. Here, to investigate an efficient siRNA transfection method using cationic liposomes, we compared the transfection efficiency of siRNA between Fw-transfection and Rev-transfection methods with various types of cationic liposomes. In Fw-transfection, siRNA/cationic liposomes complex (siRNA lipoplexes) was added to pre-plated cells. In contrast, Rev-transfection was performed by co-incubation of cells with siRNA lipoplexes in suspension. As a result, Rev-transfection with 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP)-based or cationic cholesterol derivative-based liposomes could deliver siRNA into the cells via efficient cellular association, and induce an improved gene silencing effect by siRNA compared with Fw-transfection. Furthermore, Rev-transfection did not show increased cytotoxicity compared with Fw-transfection. These findings suggested that Rev-transfection in suspension has better potential for efficient transfection of siRNA into cells with minimal toxicity.

Expression of Telomerase Reverse Transcriptase during the Malignant Transformation of Cadmium-Induced Cells

The objective of the present study was to investigate human telomerase reverse transcriptase (hTERT) mRNA and protein expressions during the cadmium chloride-induced malignant transformation of human bronchial epithelial (16HBE) cells. Fluorescence quantitative PCR (FQ-PCR) and Western blot analyses were performed to detect the hTERT mRNA and protein expressions in normal 16HBE cells, cadmium chloride-transformed 16HBE cells, and tumorigenic cells from nude mice inoculated with cadmium chloride-transformed 16HBE cells. Under the inner standard of GAPDH, the hTERT mRNA expression was significantly higher at different stages of malignant transformation (cadmium chloride-transformed 16HBE cells at passages 15 and 35 and tumorigenic cells from nude mice) than in normal 16HBE cells, and increased with the development of malignancy (P < 0.01). In addition, hTERT protein expression increased with the development of malignancy. These findings demonstrate that hTERT expression is related to cadmium chlorideinduced malignant transformation. Cadmium chloride-induced malignant transformation is involved in changes in the hTERT activity, and might be an early event in cadmium chloride-induced malignant transformation.