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Poly ADP-ribose polymerase (PARP) inhibitor monotherapies are selectively effective in patients with pancreatic, breast, prostate, and ovarian cancers with BRCA1 mutations. Cancer patients with more frequent wild-type BRCA show poor responses to PARP inhibitors. Moreover, patients who are initially sensitive to these inhibitors eventually respond poorly to drugs. In the present study, we discover that abrogation of Kruppel-like factor 5 (KLF5) significantly inhibits homologous recombination, which is the main mechanism for DNA double-stranded repair. Furthermore, the downregulation of KLF5 expression promotes the DNA damage induced by olaparib and significantly reduces the IC50 of the RARP inhibitor in pancreatic cancer cells. Overexpression of BRCA1 reverses the above effects caused by silencing of KLF5. Olaparib combined with a KLF5 inhibitor has an enhanced cytotoxic effect. Mechanistically, we identify BRCA1 as a KLF5 target gene. BRCA1 is positively correlated with KLF5 in PDAC tissue. Our results indicate that inhibition of KLF5 may induce BRCAness in a larger pancreatic cancer subset with proficient BRCA. The combination of KLF5 inhibitors and PARP inhibitors provides a novel treatment strategy to enhance the sensitivity of BRCA1-proficient pancreatic cancer to PARP inhibitors.

The key to advancing lithium‐ion battery (LIB) technology, particularly with respect to the optimization of cycling protocols, is to obtain comprehensive and in‐depth understanding of the dynamic electrochemical processes during battery operation. This work shows that pulse current (PC) charging substantially enhances the cycle stability of commercial LiNi0.5Mn0.3Co0.2O2 (NMC532)/graphite LIBs. Electrochemical diagnosis unveils that pulsed current effectively mitigates the rise of battery impedance and minimizes the loss of electrode materials. Operando and ex situ Raman and X‐ray absorption spectroscopy reveal the chemical and structural changes of the negative and positive electrode materials during PC and constant current (CC) charging. Specifically, Li‐ions are more uniformly intercalated into graphite and the Ni element of NMC532 achieves a higher energy state with less Ni─O bond length variation under PC charging. Besides, PC charging suppresses the electrolyte decomposition and continuous thickening of the solid‐electrolyte‐interphase (SEI) layer on graphite anode. These findings offer mechanistic insights into Li‐ion storage in graphite and NMC532 and, more importantly, the role of PC charging in enhancing the battery cycling stability, which will be beneficial for advancing the cycling protocols for future LIBs and beyond. [ABSTRACT FROM AUTHOR]

Understanding the influence of electrode material's morphology on electrochemical behavior is of great significance for the development of rechargeable batteries, however, such studies are often limited by the inability to precisely control the morphology of electrode materials. Herein, nanostructured titanium niobium oxides (TiNb2O7) with three different morphologies (one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D)) were synthesized via a facile microwave-assisted solvothermal method. The influence of the morphological dimension of TiNb2O7 as electrode material on the electrochemical performance in Li-ion batteries (LIBs) and the underlying correlation with the electrochemical kinetics were studied in detail. 2D TiNb2O7 (TNO-2D) shows a superior rate capability and cycling stability, associated with improved kinetics for charge transfer and Li-ion diffusion, compared to the 1D and 3D materials. Operando X-ray diffraction measurements reveal the structural stability and crystallographic evolution of TNO-2D upon lithiation and delithiation and correlate the Li-ion diffusion kinetics with the lattice evolution during battery charge and discharge. Moreover, carbon-coated TNO-2D achieves enhanced rate capability (205 mAh·g−1 at 50 C) and long-term cycling stability (87% after 1000 cycles at 5 C). This work provides insights into the rational morphology design of electrode materials for accelerated charge transfer and enhanced fast-charging capability, pushing forward the development of electrode materials for high-power rechargeable batteries in future energy storage. [ABSTRACT FROM AUTHOR]

A combination of static and time-resolved spectroscopic techniques has been applied to study the low-lying excited electronic states of protein-encapsulated Au nanoclusters in terms of their energy levels and relaxation mechanisms. The energy levels were determined using photoluminescence (PL) spectroscopy. The excited state dynamics were probed using time-resolved PL techniques as well as femtosecond transient absorption (TA) spectroscopy. A simple model was proposed to account for the key spectral and dynamic features observed. This study has added new insight to the optical and dynamic properties of metal nanoclusters of interest in many applications including solar energy conversion and biomedical imaging. © 2014 Elsevier B.V.

The development of freestanding and binder‐free electrode is an effective approach to perform the inherent capacity of active materials and promote the mechanism study by minimizing the interference from additives. Herein, we construct a freestanding cathode composed of MoS3/PPy nanowires (NWs) deposited on porous nickel foam (NF) (MoS3/PPy/NF) through electrochemical methods, which can work efficiently as sulfur‐equivalent cathode material for Li‐S batteries. The structural stability of the MoS3/PPy/NF cathode is greatly enhanced due to its significant tolerance to the volume expansion of MoS3 during the lithiation process, which we ascribe to the flexible 3D framework of PPy NWs, leading to superior cycling performance compared to the bulk‐MoS3/NF reference. Eliminating the interference of binder and carbon additives, the evolution of the chemical and electronic structure of Mo and S species during the discharge/charge was studied by X‐ray absorption near‐edge spectroscopy (XANES). The formation of lithium polysulfides was excluded as the driving cathode reaction mechanism, suggesting the great potential of MoS3 as a promising sulfur‐equivalent cathode material to evade the shuttle effect for Li‐S batteries. The present study successfully demonstrates the importance of structural design of freestanding electrode enhancing the cycling performances and revealing the corresponding mechanisms. [ABSTRACT FROM AUTHOR]

Lithium (Li) metal batteries (LMBs) are the "holy grail" in the energy storage field due to their high energy density (theoretically >500 Wh kg−1). Recently, tremendous efforts have been made to promote the research & development (R&D) of pouch‐type LMBs toward practical application. This article aims to provide a comprehensive and in‐depth review of recent progress on pouch‐type LMBs from full cell aspect, and to offer insights to guide its future development. It will review pouch‐type LMBs using both liquid and solid‐state electrolytes, and cover topics related to both Li and cathode (including LiNixCoyMn1‐x‐yO2, S and O2) as both electrodes impact the battery performance. The key performance criteria of pouch‐type LMBs and their relationship in between are introduced first, then the major challenges facing the development of pouch‐type LMBs are discussed in detail, especially those severely aggravated in pouch cells compared with coin cells. Subsequently, the recent progress on mechanistic understandings of the degradation of pouch‐type LMBs is summarized, followed with the practical strategies that have been utilized to address these issues and to improve the key performance criteria of pouch‐type LMBs. In the end, it provides perspectives on advancing the R&Ds of pouch‐type LMBs towards their application in practice. [ABSTRACT FROM AUTHOR]

The growing demand for energy-dense and safe batteries drives research towards all-solid-state lithium (Li) batteries. Existing poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) suffer from low Li+ conductivity and Li dendrite penetration. Covalent organic frameworks (COFs) as highly crystalline, porous, and chemically diverse organic materials show great potential to address these problems. However, extensively studied imine-linked COFs show insufficient electrochemical stability against reactive Li metal, limiting their application for Li batteries. Herein, we develop a chemically stable vinylene-linked covalent organic framework (VCOF)-based SPE. By incorporating <4 wt% VCOF-1, a 25% improvement in ionic conductivity and a 46% increase in Li+ transference number at 60 °C are achieved. DFT calculations reveal that VCOF-1 facilitates Li+ transport through its cylindrical pores aided by PEO. In situ X-ray tomography confirms that VCOF-1 substantially suppresses Li dendrite growth in the VCOF-SPE-based Li metal batteries attributed to the enhanced Li-ion conduction and 12-fold improved mechanical strength. VCOF-SPEs also exhibit a high capacity of ∼145 mA h g−1 at 0.1C in LiFePO4‖Li coin cells. Notably, the LiFePO4‖Li pouch cell withstands abuse test conditions such as folding, cutting, and nail penetration. These results demonstrate the potential of VCOFs in future all-solid-state Li metal batteries for energy storage. [ABSTRACT FROM AUTHOR]

Constant current charging and discharging is widely used nowadays for commercial lithium (Li) ion batteries (LIBs) in applications of portable electronic devices and electric vehicles. However, the main battery degradation mechanism during constant current cycling remains unclear. In this work, electrochemical cycling, real-time temperature monitoring, and operando electrochemical impedance spectroscopy of a fresh and an aged battery have been carried out to unveil the aging mechanism during constant current cycling. The results of the incremental capacity analysis (ICA) indicate that polarization is the main reason for the capacity fading during operation. Besides, post-mortem analysis of the electrodes reveals that the formation of a solid–electrolyte interphase (SEI) and cathode–electrolyte interphase (CEI) is the leading cause of electrode degradation. The interface formation and evolution over cycling (including thickening and chemical variation) leads to continuous loss of active materials. The presence of a SEI and CEI also increases the impedance for charge transfer and transport and reduces the kinetics of electrochemical Li-ion redox on the electrodes. Moreover, the irreversible Li loss due to Li plating and SEI formation has been quantified, which accounts for 16.8% of the total Li in the battery. This work provides a mechanistic understanding of the degradation mechanism of commercial LIBs, guides the rational design of commercial batteries and inspires the design of charging and discharging protocols toward enhanced cycling stability and prolonged cycle life. [ABSTRACT FROM AUTHOR]