New prospects of cancer therapy based on pyroptosis and pyroptosis inducers.

Pyroptosis is a gasdermin-mediated programmed cell death (PCD) pathway. It differs from apoptosis because of the secretion of inflammatory molecules. Pyroptosis is closely associated with various malignant tumors. Recent studies have demonstrated that pyroptosis can either inhibit or promote the development of malignant tumors, depending on the cell type (immune or cancer cells) and duration and severity of the process. This review summarizes the molecular mechanisms of pyroptosis, its relationship with malignancies, and focuses on current pyroptosis inducers and their significance in cancer treatment. The molecules involved in the pyroptosis signaling pathway could serve as therapeutic targets for the development of novel drugs for cancer therapy. In addition, we analyzed the potential of combining pyroptosis with conventional anticancer techniques as a promising strategy for cancer treatment.

Intricate Ionic Behaviors in High-Performance Self-Powered Hydrothermal Chemical Generator Using Water and Iron (III) Gate.

Utilizing the ionic flux to generate voltage output has been confirmed as an effective way to meet the requirements of clean energy sources. Different from ionic thermoelectric (i-TE) and hydrovoltaic devices, a new hydrothermal chemical generator is designed by amorphous FeCl3 particles dispersing in MWCNT and unique ferric chloride or water gate. In the presence of gate, the special ion behaviors enable the cell to present a constant voltage of 0.60 V lasting for over 96 h without temperature difference. Combining the differences of cation concentration, humidity and temperature between the right and left side of sample, the maximum short-circuit current and power output can be obtained to 168.46 µA and 28.11 µW, respectively. The generator also can utilize the low-grade heat to produce electricity wherein Seebeck coefficient is 6.79 mV K-1 . The emerged hydrothermal chemical generator offers a novel approach to utilize the low-grade heat, water and salt solution resources, which provides a simple, sustainable and low-cost strategy to realize energy supply.

A new In Situ Oxidized 2D Layered MnBi2Te4 Cathode for High-Performance Aqueous Zinc-Ion Battery.

Recently, aqueous zinc ion batteries (AZIBs) with the superior theoretical capacity, high safety, low prices, and environmental protection, have emerged as a contender for advanced energy storage. However, challenges related to cathode materials, such as dissolution, instability, and structural collapse, have hindered the progress of AZIBs. Here, a novel AZIB is constructed using an oxidized 2D layered MnBi2Te4 cathode for the first time. The oxidized MnBi2Te4 cathode with large interlayer spacing and low energy barrier for zinc ion diffusion at 240 °C, exhibited impressive characteristics, including a high reversibility capacity of 393.1 mAh g-1 (0.4 A g-1), outstanding rate performance, and long cycle stability. Moreover, the corresponding aqueous button cell also exhibits excellent electrochemical performance. To demonstrate the application in practice in the realm of flexible wearable electronics, a quasi-solid-state micro ZIB (MZIB) is constructed and shows excellent flexibility and high-temperature stability (the capacity does not significantly degrade when the temperature reaches 100 °C and the bending angle exceeds 150°). This research offers effective tactics for creating high-performance cathode materials for AZIBs.

Template-Assisted Synthesis of 2D Perovskite Grating Single Crystal Films at Low Temperatures for UV Polarization-Sensitive Photodetectors.

2D perovskites have attracted tremendous attention due to their superior optoelectronic properties and potential applications in optoelectronic devices. Especially, the larger bandgap of 2D perovskite means that they are suitable for UV photodetection. However, the layered structure of 2D perovskites hinders the interlayer carrier transport, which limits the improvement of device performance. Therefore, nanoscale structures are normally used to enhance the light absorption ability, which is an effective strategy to improve the photocurrent in 2D perovskite-based photodetectors. Herein, a template-assisted low-temperature method is proposed to fabricate 2D perovskite ((C6H5C2H4NH3)2PbBr4, (PEA)2PbBr4) grating single crystal films (GSCFs). The crystallinity of the (PEA)2PbBr4 GSCFs is significantly improved due to the slow evaporation of the precursor solution under low temperatures. Based on this high crystalline quality and extremely ordered microstructures, the metal-semiconductor-metal photodetectors are assembled. Finite-different time-domain (FDTD) simulation and experiment indicate that the GSCF-based photodetectors exhibit significantly improved performance in comparison with the plane devices. The optimized 2D perovskite photodetectors are sensitive to UV light and demonstrate a responsivity and detectivity of 28.6 mA W-1 and 2.4 × 1011 Jones, respectively. Interestingly, the photocurrent of this photodetector varies as the angle of the incident polarized light, resulting in a high polarization ratio of 1.12.

Progress in research on the role played by myeloid-derived suppressor cells in liver diseases.

Myeloid-derived suppressor cells (MDSCs) refer to a group of immature myeloid cells with potent immunosuppressive capacity upon activation by pathological conditions. Because of their potent immunosuppressive ability, MDSCs have garnered extensive attention in the past few years in the fields of oncology, infection, chronic inflammation and autoimmune diseases. Research on MDSCs in liver diseases has gradually increased, and their potential therapeutic roles will be further explored. This review presents a summary of the involvement and the role played by MDSCs in liver diseases, thus identifying their potential targets for the treatment of liver diseases and providing new directions for liver disease-related research.

Porous Pure MXene Fibrous Network for Highly Sensitive Pressure Sensors.

Wearable and elastic pressure sensors have caused widespread concern due to the popularity of smart terminals and human health monitoring. To obtain a flexible pressure sensor with a wide detection region and outstanding sensitivity, exploring new materials and novel structures has become the first choice for the research. Here, a wearable and flexible MXene fibrous network pressure sensor (MFNS) with a high sensitivity and wide detection region is reported. The holistic fiber network is composed of pure MXene fibers; among them, MXene fibers were prepared by wet-spinning of MXene nanosheets. The MFNS exhibits a high sensitivity in a wide detection region (51 kPa-1 for 14.7 kPa and 427 kPa-1 within the 14.7-19.9 kPa range), a low detection limit (8 Pa), a robust durability (10,000 cycles), and a prompt response (95 ms). Due to the superior performance of MFNS, it also proves prospective applications for human motion signal detection (such as swallowing, pulse beat, and joint motion) and measuring pressure distribution. This work provides an effective way to fabricate a high-performance pressure sensor for human-machine interactions, personal healthcare monitoring, and multitouch devices.

Highly Transparent and Flexible Zn-Ti3C2Tx MXene Hybrid Capacitors.

With the development of transparent and wearable electronic devices, energy supply units with high transmittance and flexibility, long cycle life, and high power and energy density are urgently needed. Zinc ion hybrid capacitors (ZIHCs) combined with the advantages of both supercapacitors and zinc ion batteries are promising energy supply components in the abovementioned devices. In addition, the preparation of multifunctional devices has become a trend for the need of space- and resource-saving. Therefore, obtaining ZIHCs with high transmittance and exploring their potential applications are meaningful challenges. Herein, a transparent and flexible ZIHC composed of a patterned zinc foil anode, transparent MXene cathode, and ZnSO4-polyacrylamide (PAM) hydrogel electrolyte is designed and realized. The ZIHC exhibits a superior capacitance of 318 µF cm-2 (5 mV s-1) with 94% transmittance and retains 76% of the initial capacitance after 10,000 charge-discharge cycles. It also shows excellent flexibility, i.e., its capacitance has no obvious attenuation under different bending states. Interestingly, the leakage current of the ZIHC is highly sensitive to electric fields, which shows potential application in electric field detection. This work presents a method to realize the multifunctional ZIHC with electric field sensing function for transparent and flexible wearable devices in the future.

miRNA-146a-5p mitigates stress-induced premature senescence of D-galactose-induced primary thymic stromal cells.

Senescent thymic stromal cells (TSCs) producing senescence-associated secretory phenotype (SASP) may play a role at later phases of thymic involution. However, the etiology and mechanisms responsible for TSC senescence remain to be elucidated. In the present study, the effects of oxidative stress on TSCs and role of miRNA-146a-5p in stress-induced premature senescence (SIPS) were identified. D-galactose (D-gal) induced oxidative stress in primary TSCs and a limited cumulative oxidative stress induced premature senescence but not apoptosis of TSCs. miRNA-146a-5p overexpression can mitigate the SIPS by targeting tumor necrosis factor receptor-associated factor 6 (TRAF6) instead of increasing autophagy clearance. Furthermore, exogenous miRNA-146a-5p reversed the upregulation of chemokines including Cxcl5, pro-inflammatory cytokines, and antimicrobial peptides in TSCs with SIPS. In conclusion, the accumulated oxidative stress may be partially responsible for senescence in TSCs and modulation of miRNA-146a-5p may attenuate this process.

Elevenin signaling modulates body color through the tyrosine-mediated cuticle melanism pathway.

Elevenin is a newly discovered novel neuropeptide. Knockdown of either elevenin or orphan receptor NlA42 transcript expression by RNA interference caused severe cuticle melanization in the brown planthopper (BPH). Injection of a synthetic elevenin peptide not only rescued the body color phenotype in dselevenin-pretreated individuals but also suppressed melanization of black insects grown in natural conditions. Real-time quantitative PCR results revealed that elevenin expression levels were highest in the brain and salivary gland. Immunohistochemistry analysis confirmed that a precursor peptide of elevenin was generated in the salivary gland, suggesting that the salivary gland might be an important neurosecretory tissue in addition to the brain in BPH. Furthermore, double-strand RNA-mediated silencing of elevenin and NlA42 resulted in down-regulation of arylalkylamine-N-acetyltransferase and up-regulation of tyrosine hydroxylase, whereas elevenin peptide injection resulted in up-regulation of N-ß-alanyldopamine synthase and aspartate 1-decarboxylase, indicating a complex regulation network for cuticle pigmentation. In addition, functional characterization demonstrated that NlA42 is a cognate receptor for elevenin, and couples to Gq and Gs proteins, triggering both PLC/Ca2+/PKC and AC/cAMP/PKA signaling pathways in response to elevenin treatment. These findings suggest that the elevenin signaling functions control BPH body color through the tyrosine-mediated cuticle melanism pathway.-Wang, S.-L., Wang, W.-W., Ma, Q., Shen, Z.-F., Zhang, M.-Q., Zhou, N.-M., Zhang, C.-X. Elevenin signaling modulates body color through the tyrosine-mediated cuticle melanism pathway.

Optical-electrical-thermal optimization of plasmon-enhanced perovskite solar cells.

Metal nanoparticles associated with local surface plasmon (LSP) resonance, i.e. highly confined electric field and large scattering cross-sections (σ), have been widely used to enhance the light-harvesting of solar cells toward high optoelectronic performance. However, the metal nanoparticles embedded into the solar cells suffer from parasitic ohmic loss that subsequently causes the local temperature to rise, which, in turn, reduces the photoelectric conversion efficiency and stability of solar cells. Previous studies on plasmon-enhanced solar cells have rarely considered the negative effects of metal nanoparticles' ohmic losses and temperature rise on solar cell performance optimization. Therefore, it is of great interest to alleviate the ohmic loss and temperature rise that are critical for high-performance solar cells. Herein, we propose a model to comprehensively study and optimize the performance of plasmon-enhanced perovskite solar cells (PSCs) from simultaneous optical-electrical-thermal aspects. First, the optical simulation results indicated that the geometric tuning of metal nanoparticles can make full use of the plasmonic effect and significantly improve PSCs' light absorption. The analysis showed that the embedded nanoparticles with optimal geometry in PSC devices can significantly increase the optical absorption by 17% (41%) compared to non-optimal nanostructures (devices without nanoparticles). Then, we explored the influence of the temperature-dependent carrier mobility on PSC performance from the coupled electrical and thermal studies. Our results indicated that the optimization of the geometrical parameters of metal nanoparticles can minimize energy dissipation, thereby redusing the heat loss and then lowering the local cell temperature. Interestingly, PSCs' electrical properties such as carrier transportation significantly improved. Consequently, the PSC performance improved with increment in the short-circuit current by 23% and the power conversion efficiency by 38%.

Correction to: Cryptotanshinone activates AMPK-TSC2 axis leading to inhibition of mTORC1 signaling in cancer cells.

Following publication of the original article [1], the author noticed the following errors in the article.

Episodic Memory Retrieval Benefits from a Less Modular Brain Network Organization.

Most complex cognitive tasks require the coordinated interplay of multiple brain networks, but the act of retrieving an episodic memory may place especially heavy demands for communication between the frontoparietal control network (FPCN) and the default mode network (DMN), two networks that do not strongly interact with one another in many task contexts. We applied graph theoretical analysis to task-related fMRI functional connectivity data from 20 human participants and found that global brain modularity-a measure of network segregation-is markedly reduced during episodic memory retrieval relative to closely matched analogical reasoning and visuospatial perception tasks. Individual differences in modularity were correlated with memory task performance, such that lower modularity levels were associated with a lower false alarm rate. Moreover, the FPCN and DMN showed significantly elevated coupling with each other during the memory task, which correlated with the global reduction in brain modularity. Both networks also strengthened their functional connectivity with the hippocampus during the memory task. Together, these results provide a novel demonstration that reduced modularity is conducive to effective episodic retrieval, which requires close collaboration between goal-directed control processes supported by the FPCN and internally oriented self-referential processing supported by the DMN.SIGNIFICANCE STATEMENT Modularity, an index of the degree to which nodes of a complex system are organized into discrete communities, has emerged as an important construct in the characterization of brain connectivity dynamics. We provide novel evidence that the modularity of the human brain is reduced when individuals engage in episodic memory retrieval, relative to other cognitive tasks, and that this state of lower modularity is associated with improved memory performance. We propose a neural systems mechanism for this finding where the nodes of the frontoparietal control network and default mode network strengthen their interaction with one another during episodic retrieval. Such across-network communication likely facilitates effective access to internally generated representations of past event knowledge.

Targeting Thioredoxin System with an Organosulfur Compound, Diallyl Trisulfide (DATS), Attenuates Progression and Metastasis of Triple-Negative Breast Cancer (TNBC).

BACKGROUND/AIMS: Metastasis is the leading cause resulting in high mortality in triple negative breast cancer (TNBC) patients. Cancer cells are skilled at utilizing thioredoxin (Trx) system as an efficient antioxidant system to counteract oxidative damage, facilitating the occurrence of metastasis. Here, we identified an organosulfur compound named DATS isolated from garlic, that inhibits the expression of Trx-1 and the enzyme activity of Trx reductase in breast cancer cells. METHODS: Tissue microarray of breast cancer patients and immunohistochemical method were used to analyze the role of Trx-1 in breast cancer metastasis. Spotaneous metastasis model and experimental metastasis model combined with HE staining, immunohistochemistry were used to verify in vivo anti-metastatic effect of DATS as well as its regulation on thioredoxin. Western blot, immunofluorescence, redox state assessment and detection of enzyme activity were employed to determine the effect of DATS on thioredoxin system. Trx-1 siRNA interference was used to investigate the conclusive evidence that Trx-1 was the target of DATS. RESULTS: In agreement with reduced Trx-1 nuclear translocation from cytoplasm by DATS, the production of reduced form of Trx-1 was dramatically decreased. Furthermore, in vivo, DATS administration was observed to significantly suppress spontaneous and experimental metastasis in nude mice. Delivery of DATS also resulted in decreased expression of Trx-1 as the direct target, as well as expression of NF-κB and MMP2/9 in primary tumor and lung tissue. Notably, the effects of DATS on the expression of downstream metastasis-associated genes were mediated by Trx-1, as demonstrated by the combination use of DATS and Trx-1 siRNA. CONCLUSION: Collectively, this present study indicates that targeting Trx system with DATS may provide a promising strategy for treating metastasis of TNBC.

Cryptotanshinone inhibition of mammalian target of rapamycin pathway is dependent on oestrogen receptor alpha in breast cancer.

Cryptotanshinone (CPT) has been demonstrated to inhibit proliferation and mammalian target of rapamycin (mTOR) pathway in MCF-7 breast cancer cells. However, the same results are unable to be repeated in MDA-MB-231 cells. Given the main difference of oestrogen receptor α (ERα) between two types of breast cancer cells, It is possibly suggested that CPT inhibits mTOR pathway dependent on ERα in breast cancer. CPT could significantly inhibit cell proliferation of ERα-positive cancer cells, whereas ERα-negative cancer cells are insensitive to CPT. The molecular docking results indicated that CPT has a high affinity with ERα, and the oestrogen receptor element luciferase reporter verified CPT distinct anti-oestrogen effect. Furthermore, CPT inhibits mTOR signalling in MCF-7 cells, but not in MDA-MB-231 cells, which is independent on binding to the FKBP12 and disrupting the mTOR complex. Meanwhile, increased expression of phosphorylation AKT and insulin receptor substrate (IRS1) induced by insulin-like growth factor 1 (IGF-1) was antagonized by CPT, but other molecules of IGF-1/AKT/mTOR signalling pathway such as phosphatase and tensin homolog (PTEN) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) were negatively affected. Finally, the MCF-7 cells transfected with shERα for silencing ERα show resistant to CPT, and p-AKT, phosphorylation of p70 S6 kinase 1 (p-S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1) were partially recovered, suggesting ERα is required for CPT inhibition of mTOR signalling. Overall, CPT inhibition of mTOR is dependent on ERα in breast cancer and should be a potential anti-oestrogen agent and a natural adjuvant for application in endocrine resistance therapy.

Cryptotanshinone activates AMPK-TSC2 axis leading to inhibition of mTORC1 signaling in cancer cells.

BACKGROUND: Cryptotanshinone (CPT), a fat-soluble phenanthraquinone from Salvia miltiorrhiza Bunge, has been demonstrated to inhibit phosphorylation of p70 S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1), a couple of direct downstream effectors of the mammalian target of rapamycin complex 1 (mTORC1), resulting in cancer cell arrested in G0 phase and subsequent inhibition of proliferation. However, its concrete molecular mechanism about how CPT inhibits mTORC1 signaling pathway is unclear. METHODS: one solution was used to check cell viability and western blotting for determining expression of the indicated proteins. Molecular docking was performed to assess the binding of CPT with mTOR. The co-immunoprecipitation assay was to analyze whether CPT could disrupt the mTORC1 and TSC1/TSC2 complex. Recombinant adenoviral dominant-negative AMPKα was used to downregulate expression of AMPKα and lentiviral AMPK and TSC2 to silence the AMPK and TSC2 in Rh30 cells. RESULTS: Primarily, Rh30 cells expressing rapamycin-resistant mutant mTOR are also sensitive to CPT, while the molecular docking result for CPT binding to mTOR is negative, suggesting that CPT inhibition of mTORC1 is different from rapamycin. Then the related proteins of PTEN-PI3K pathway was proved not to be affected, but the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) was activated by a concentration- and time- dependent manner, meaning that it may be associated with AMPK. Further results indicated that compound C, inhibitor of AMPK, could clearly reversed CPT inhibitory effect on Rh30 cells, and dominant-negative AMPK in cancer cells conferred resistance to CPT inhibition of 4E-BP1 and phosphorylation of S6K1, as well as sh-AMPK. Furthermore, compared with AMPK-positive MEF cells, AMPK-negative MEF cells are less sensitive to CPT by the findings that 4E-BP1 and phosphorylation of S6K1 express comparatively more. Additionally, phosphorylation of tuberous sclerosis complex 2 (TSC2) was activated under the treatment of CPT, and down-expression of TSC2 by shRNA slightly recovered expression of 4E-BP1 and phosphorylation of S6K1, while co-immunoprecipitation of TSC2 did not alter expression of TSC1 by CPT. CONCLUSION: CPT inhibiting mTORC1 pathway was mostly due to activation of AMPK-TSC2 axis rather than specific binding to mTORC1. CPT is a potent anticancer agent targeting AMPK.

Diet phytochemicals and cutaneous carcinoma chemoprevention: A review.

Cutaneous carcinoma, which has occupied a peculiar place among worldwide populations, is commonly responsible for the considerably increasing morbidity and mortality rates. Currently available medical procedures fail to completely avoid cutaneous carcinoma development or to prevent mortality. Cancer chemoprevention, as an alternative strategy, is being considered to reduce the incidence and burden of cancers through chemical agents. Derived from dietary foods, phytochemicals have become safe and reliable compounds for the chemoprevention of cutaneous carcinoma by relieving multiple pathological processes, including oxidative damage, epigenetic alteration, chronic inflammation, angiogenesis, etc. In this review, we presented comprehensive knowledges, main molecular mechanisms for the initiation and development of cutaneous carcinoma as well as effects of various diet phytochemicals on chemoprevention.

Untargeted metabolomics analysis of adipogenic transformation in OP9-DL1 cells using liquid chromatography-mass spectrometry: Implications for thymic adipogenesis.

Adipocyte deposition is a key feature of age-related thymic involution, but the underlying mechanisms responsible for thymic adiposity remain to be elucidated. In the present study, we utilized rosiglitazone, a potent peroxisome proliferator-activated receptor γ agonist, to induce adipogenic differentiation of OP9-DL1 cells, and detected the metabolomics alterations during adipogenic differentiation by using liquid chromatography-mass spectrometry. The obtained metabolites were further processed by multivariate statistical analysis, including principal component analysis, partial least squares discriminant analysis, and orthogonal projection on latent-structures discriminant analysis. As a result, we identified a total of 33 significantly differential metabolites between dimethyl sulphoxide- and rosiglitazone-treated OP9-DL1 cells, which were closely related to the dysregulation of phospholipid metabolism pathway, oxidative stress, and associated amino acid metabolism. Meanwhile, two pathways including glycerophospholipid metabolism and nitrogen metabolism were significantly perturbed (P < 0.05). Collectively, our results may provide some heuristic guidance for addressing the underlying mechanism of thymic adipogenesis, and future studies are warranted to unravel the functions of these altered metabolites in thymic adipogenesis.

A Cripavirus in the brown planthopper, Nilaparvata lugens.

A Cripavirus-like long unique sequence was identified during transcriptome sequencing of the brown planthopper (BPH), Nilaparvata lugens. This unique sequence demonstrated high similarity with the whole-genome sequence of cricket paralysis virus, including 5' and 3' untranslated regions; thus we considered it the whole genome of a new virus. We propose that the virus be named Nilaparvata lugens C virus (NlCV). The plus-strand RNA genome spanned 9144 nt, excluding a 3' poly(A) tail with two large ORFs encoding structural and non-structural proteins, respectively. Detection of NlCV in BPH honeydew raised the hypothesis of horizontal transmission of the virus. Honeydew from viruliferous BPHs was used to feed non-viruliferous insects, the results of which indicated that the BPH could acquire NlCV through feeding and that the virus could multiply in the insect body. A tissue-specific distribution test using real-time quantitative PCR demonstrated that NlCV was mainly present in the reproductive organs, and the virus was detected in eggs laid by viruliferous female insects using nested PCR, indicating the possibility of vertical transmission as well. As no significant symptom was detected in the viruliferous BPH, NlCV is considered a new commensal virus of BPH. Interestingly, this virus was also detected in two other hemipteran insects, the white-backed planthopper and the horned gall aphid, indicating that NlCV might be present in many other hemipteran insects and have a wide host range.

Enhancing light emission in flexible AC electroluminescent devices by tetrapod-like zinc oxide whiskers.

Flexible alternating current electroluminescent devices (ACEL) are more and more popular and widely used in liquid-crystal display back-lighting, large-scale architectural and decorative lighting due to their uniform light emission, low power consumption and high resolution. However, presently how to acquire high brightness under a certain voltage are confronted with challenges. Here, we demonstrate an electroluminescence (EL) enhancing strategy that tetrapod-like ZnO whiskers (T-ZnOw) are added into the bottom electrode of carbon nanotubes (CNTs) instead of phosphor layer in flexible ACEL devices emitting blue, green and orange lights, and the brightness is greatly enhanced due to the coupling between the T-ZnOw and ZnS phosphor dispersed in the flexible polydimethylsiloxane (PDMS) layer. This strategy provides a new routine for the development of high performance, flexible and large-area ACEL devices.

UV-free red electroluminescence from the cross-connected p-ZnO:Cu nanobushes/n-GaN light emitting diode.

A p-ZnO:Cu/n-GaN heterojunction light emitting diode (LED) is fabricated by growing cross-connected p-ZnO:Cu nanobushes on n-GaN film using chemical vapor deposition under oxygen-rich condition. This LED emits stable UV-free red light of 677 nm and 745 nm. The electroluminescence (EL) light of this LED is tuned from ultraviolet (UV) of ZnO/GaN to UV-free red by the electronic interfacial transition from the conduction band of n-GaN to the deep acceptor levels of p-ZnO:Cu. Both room temperature and low temperature (5K) photoluminescence spectra of ZnO:Cu indicate that the UV emission of ZnO is suppressed and the green emission is enhanced, which implies the formation of Cu-related deep levels introduced by intentionally doping Cu in ZnO. These deep levels help the EL red emission in the LED device.