Showing papers by "Jilin University published in 2018"

Efficient and stable emission of warm-white light from lead-free halide double perovskites

Abstract: Lighting accounts for one-fifth of global electricity consumption1. Single materials with efficient and stable white-light emission are ideal for lighting applications, but photon emission covering the entire visible spectrum is difficult to achieve using a single material. Metal halide perovskites have outstanding emission properties2,3; however, the best-performing materials of this type contain lead and have unsatisfactory stability. Here we report a lead-free double perovskite that exhibits efficient and stable white-light emission via self-trapped excitons that originate from the Jahn–Teller distortion of the AgCl6 octahedron in the excited state. By alloying sodium cations into Cs2AgInCl6, we break the dark transition (the inversion-symmetry-induced parity-forbidden transition) by manipulating the parity of the wavefunction of the self-trapped exciton and reduce the electronic dimensionality of the semiconductor4. This leads to an increase in photoluminescence efficiency by three orders of magnitude compared to pure Cs2AgInCl6. The optimally alloyed Cs2(Ag0.60Na0.40)InCl6 with 0.04 per cent bismuth doping emits warm-white light with 86 ± 5 per cent quantum efficiency and works for over 1,000 hours. We anticipate that these results will stimulate research on single-emitter-based white-light-emitting phosphors and diodes for next-generation lighting and display technologies. After alloying with metal cations, a lead-free halide double perovskite shows stable performance and remarkably efficient white-light emission, with possible applications in lighting and display technologies.

Pursuing sustainable productivity with millions of smallholder farmers.

Abstract: Millions of Chinese smallholder farmers were persuaded to adopt enhanced management practices, which led to a greater yield, reduced nitrogen fertilizer use and improved environmental performance throughout China. Two and a half billion smallholder farmers collectively manage 60 per cent of the world's arable land. How these farmers perform determines their own livelihood, but also affects global food security and ecosystem health. Here, Fusuo Zhang and colleagues show how some straightforward interventions have substantially improved the productivity and environmental performance of smallholder farmers across China over the past ten years. The team carried out more than 13,000 field trials across China's main agroecological zones and found that a series of management practices, collectively termed integrated soil–crop system management, increased maize, wheat and rice yields, nitrogen-use efficiency and farmer profitability. Scaling this approach up to 20.9 million smallholder farmer across 452 counties boosted grain yields to 33 million tonnes over the ten-year period, and reduced fertilizer use by 1.2 million tonnes and greenhouse gas emissions by up to 13 per cent. Sustainably feeding a growing population is a grand challenge1,2,3, and one that is particularly difficult in regions that are dominated by smallholder farming. Despite local successes4,5,6,7,8, mobilizing vast smallholder communities with science- and evidence-based management practices to simultaneously address production and pollution problems has been infeasible. Here we report the outcome of concerted efforts in engaging millions of Chinese smallholder farmers to adopt enhanced management practices for greater yield and environmental performance. First, we conducted field trials across China’s major agroecological zones to develop locally applicable recommendations using a comprehensive decision-support program. Engaging farmers to adopt those recommendations involved the collaboration of a core network of 1,152 researchers with numerous extension agents and agribusiness personnel. From 2005 to 2015, about 20.9 million farmers in 452 counties adopted enhanced management practices in fields with a total of 37.7 million cumulative hectares over the years. Average yields (maize, rice and wheat) increased by 10.8–11.5%, generating a net grain output of 33 million tonnes (Mt). At the same time, application of nitrogen decreased by 14.7–18.1%, saving 1.2 Mt of nitrogen fertilizers. The increased grain output and decreased nitrogen fertilizer use were equivalent to US$12.2 billion. Estimated reactive nitrogen losses averaged 4.5–4.7 kg nitrogen per Megagram (Mg) with the intervention compared to 6.0–6.4 kg nitrogen per Mg without. Greenhouse gas emissions were 328 kg, 812 kg and 434 kg CO2 equivalent per Mg of maize, rice and wheat produced, respectively, compared to 422 kg, 941 kg and 549 kg CO2 equivalent per Mg without the intervention. On the basis of a large-scale survey (8.6 million farmer participants) and scenario analyses, we further demonstrate the potential impacts of implementing the enhanced management practices on China’s food security and sustainability outlook.

Engineering triangular carbon quantum dots with unprecedented narrow bandwidth emission for multicolored LEDs

Abstract: Carbon quantum dots (CQDs) have emerged as promising materials for optoelectronic applications on account of carbon’s intrinsic merits of high stability, low cost, and environment-friendliness. However, the CQDs usually give broad emission with full width at half maximum exceeding 80 nm, which fundamentally limit their display applications. Here we demonstrate multicolored narrow bandwidth emission (full width at half maximum of 30 nm) from triangular CQDs with a quantum yield up to 54–72%. Detailed structural and optical characterizations together with theoretical calculations reveal that the molecular purity and crystalline perfection of the triangular CQDs are key to the high color-purity. Moreover, multicolored light-emitting diodes based on these CQDs display good stability, high color-purity, and high-performance with maximum luminance of 1882–4762 cd m−2 and current efficiency of 1.22–5.11 cd A−1. This work will set the stage for developing next-generation high-performance CQDs-based light-emitting diodes.

Nanozyme Decorated Metal-Organic Frameworks for Enhanced Photodynamic Therapy.

Abstract: Metal–organic frameworks (MOFs) have been used for photodynamic therapy (PDT) of cancers by integrating photosensitizers, which cause cytotoxic effects on cancer cells by converting tumor oxygen into reactive singlet oxygen (1O2). However, the PDT efficiency of MOFs is severely limited by tumor hypoxia. Herein, by decorating platinum nanozymes on photosensitizer integrated MOFs, we report a simple yet versatile strategy for enhanced PDT. The platinum nanoparticles homogeneously immobilized on MOFs possess high stability and catalase-like activity. Thus, our nanoplatform can facilitate the formation of 1O2 in hypoxic tumor site via H2O2-activated evolvement of O2, which can cause more serious damage to cancer cells. Our finding highlights that the composites of nanozymes and MOFs have the potential to serve as efficient agents for cancer therapy, which will open an avenue of nanozymes and MOFs toward biological applications.

Potential antibacterial mechanism of silver nanoparticles and the optimization of orthopedic implants by advanced modification technologies.

Abstract: Infection, as a common postoperative complication of orthopedic surgery, is the main reason leading to implant failure. Silver nanoparticles (AgNPs) are considered as a promising antibacterial agent and always used to modify orthopedic implants to prevent infection. To optimize the implants in a reasonable manner, it is critical for us to know the specific antibacterial mechanism, which is still unclear. In this review, we analyzed the potential antibacterial mechanisms of AgNPs, and the influences of AgNPs on osteogenic-related cells, including cellular adhesion, proliferation, and differentiation, were also discussed. In addition, methods to enhance biocompatibility of AgNPs as well as advanced implants modifications technologies were also summarized.

Self-Assembly of Transition Metal Oxide Nanostructures on MXene Nanosheets for Fast and Stable Lithium Storage.

Abstract: Recently, a new class of 2D materials, i.e., transition metal carbides, nitrides, and carbonitrides known as MXenes, is unveiled with more than 20 types reported one after another. Since they are flexible and conductive, MXenes are expected to compete with graphene and other 2D materials in many applications. Here, a general route is reported to simple self-assembly of transition metal oxide (TMO) nanostructures, including TiO2 nanorods and SnO2 nanowires, on MXene (Ti3 C2 ) nanosheets through van der Waals interactions. The MXene nanosheets, acting as the underlying substrate, not only enable reversible electron and ion transport at the interface but also prevent the TMO nanostructures from aggregation during lithiation/delithiation. The TMO nanostructures, in turn, serve as the spacer to prevent the MXene nanosheets from restacking, thus preserving the active areas from being lost. More importantly, they can contribute extraordinary electrochemical properties, offering short lithium diffusion pathways and additional active sites. The resulting TiO2 /MXene and SnO2 /MXene heterostructures exhibit superior high-rate performance, making them promising high-power and high-energy anode materials for lithium-ion batteries.

All-in-One Theranostic Nanoagent with Enhanced Reactive Oxygen Species Generation and Modulating Tumor Microenvironment Ability for Effective Tumor Eradication

Abstract: Despite regulation of the reactive oxygen species (ROS) level is an intelligent strategy for cancer therapy, the therapeutic effects of ROS-mediated therapy (including photodynamic therapy (PDT) and chemodynamic therapy (CDT)) are limited by oxygen reliance, inherent flaws of traditional photosensitizers, and strict reaction conditions of effective Fenton reaction. Herein, we reported biocompatible copper ferrite nanospheres (CFNs) with enhanced ROS production under irradiation with a 650 nm laser through direct electron transfer and photoenhanced Fenton reaction and high photothermal conversion efficiency upon exposure to an 808 nm laser, exhibiting a considerable improved synergistic treatment effect. Importantly, by exploiting the properties of O2 generation and glutathione (GSH) depletion of CFNs, CFNs relieve the hypoxia and antioxidant capability of the tumor, achieving photoenhanced CDT and improved PDT. The high relaxivity of 468.06 mM–1 s–1 enables CFNs to act as an outstanding contrast agent for...

A functional chitosan-based hydrogel as a wound dressing and drug delivery system in the treatment of wound healing

Abstract: Functional active wound dressings are expected to provide a moist wound environment, offer protection from secondary infections, remove wound exudate and accelerate tissue regeneration, as well as to improve the efficiency of wound healing. Chitosan-based hydrogels are considered as ideal materials for enhancing wound healing owing to their biodegradable, biocompatible, non-toxic, antimicrobial, biologically adhesive, biological activity and hemostatic effects. Chitosan-based hydrogels have been demonstrated to promote wound healing at different wound healing stages, and also can alleviate the factors against wound healing (such as excessive inflammatory and chronic wound infection). The unique biological properties of a chitosan-based hydrogel enable it to serve as both a wound dressing and as a drug delivery system (DDS) to deliver antibacterial agents, growth factors, stem cells and so on, which could further accelerate wound healing. For various kinds of wounds, chitosan-based hydrogels are able to promote the effectiveness of wound healing by modifying or combining with other polymers, and carrying different types of active substances. In this review, we will take a close look at the application of chitosan-based hydrogels in wound dressings and DDS to enhance wound healing.

Nanozyme: An emerging alternative to natural enzyme for biosensing and immunoassay

Abstract: Nanozyme, a term defined for nanomaterial with enzyme-like properties, has attracted significant research attention owing to its striking merits. Recently, a surge of nanozymes have been demonstrated to catalyze some typical enzymatic reactions mimicking oxidase, peroxidase and catalase. Especially, nanozymes with peroxidase-like activity have grown into a big family due to their broad range of applications in the field of biosensing and immunoassay. Since inorganic nanoparticles possess the advantages of high stability and easy surface modification, nanozymes have been emerging alternatives to natural enzymes to some extent. In this Review, we briefly summarize several typical nanozymes and then focus our attention on their enormous applications with respect to analytical chemistry. Representative examples would be discussed in detail from the literatures of last 10 years. Additionally, the current challenges and future directions about nanozymes are speculated at the end of this review.

Carbon-Quantum-Dots-Loaded Ruthenium Nanoparticles as an Efficient Electrocatalyst for Hydrogen Production in Alkaline Media

Abstract: Highly active, stable, and cheap Pt-free catalysts for the hydrogen evolution reaction (HER) are facing increasing demand as a result of their potential use in future energy-conversion systems. However, the development of HER electrocatalysts with Pt-like or even superior activity, in particular ones that can function under alkaline conditions, remains a significant challenge. Here, the synthesis of a novel carbon-loaded ruthenium nanoparticle electrocatalyst (Ru@CQDs) for the HER, using carbon quantum dots (CQDs), is reported. Electrochemical tests reveal that, even under extremely alkaline conditions (1 m KOH), the as-formed Ru@CQDs exhibits excellent catalytic behavior with an onset overpotential of 0 mV, a Tafel slope of 47 mV decade-1 , and good durability. Most importantly, it only requires an overpotential of 10 mV to achieve the current density of 10 mA cm-2 . Such catalytic characteristics are superior to the current commercial Pt/C and most noble metals, non-noble metals, and nonmetallic catalysts under basic conditions. These findings open a new field for the application of CQDs and add to the growing family of metal@CQDs with high HER performance.

Guidelines for Diagnosis and Treatment of Primary Liver Cancer in China (2017 Edition).

Abstract: Background Hepatocellular carcinoma (HCC) (about 85–90% of primary liver cancer) is particularly prevalent in China because of the high prevalence of chronic hepatitis B infection. HCC is the fourth most common malignancy and the third leading cause of tumor-related deaths in China. It poses a significant threat to the life and health of Chinese people.

H2V3O8 Nanowire/Graphene Electrodes for Aqueous Rechargeable Zinc Ion Batteries with High Rate Capability and Large Capacity

Abstract: DOI: 10.1002/aenm.201800144 the most popular electrochemical energy storage device, lithium ion batteries (LIBs) are supposed to be the most promising candidate due to its high energy density. However, in such large-scale applications, cost, lifetime, and safety are particularly important factors to be considered.[1] Compared to expensive and flammable nonaqueous LIBs, aqueous batteries with water-based electrolyte possess a natural advantage in these areas. Furthermore, they do not require strict oxygenand water-controlled manufacturing environments and thus have much lower fabrication cost. Development of aqueous battery systems progressed rapidly in recent years including monovalent Li+, Na+ and K+ and divalent Mg2+ and Zn2+ systems.[2] Among them, aqueous rechargeable zinc ion batteries (ARZIBs) attracted much attention due to the low price, rich global distribution, high stability, relatively low redox potential and high theoretic capacity (820 mA h g−1) of zinc metal, which can be directly used as the anode material. These merits of ARZIBs substantially raised their application potential in large-scale energy storage systems and even in electric vehicles. Most recently, α-MnO2, β-MnO2, and Zn0.25V2O5·nH2O nanofibers were successfully applied to ARZIBs with high energy density up to 250 W h kg−1 and very good capacity retention over thousands of cycles.[2e–g] In the development of high-performance ARZIBs, lack of suitable cathode materials is one of the biggest hindrances. Although the radius of Zn2+ ions (0.74 Å) is almost the same as that of Li+ ions (0.76 Å), the larger atomic mass and stronger positive polarity result poorer transport kinetics and lower solid-state solubility in bulk electrode. Thus, most electrode materials that can accommodate Li+ ions insertion/extraction are not suitable for ARZIBs. So far, only a few cathode materials have been demonstrated in laboratory. For example, Prussian blue analogues with a cubic open-framework structure and transition metal oxides (MnO2 and V2O5) with a layered structure exhibited acceptable reversible Zn2+ insertion/extraction.[3] However, the former delivered limited specific capacities (≈60 mA h g−1) and the latter suffered from bad cycling performance. In addition to high specific capacity, other factors including morphology, structure stability, and ionic/electronic Aqueous rechargeable zinc ion batteries are considered a promising candidate for large-scale energy storage owing to their low cost and high safety nature. A composite material comprised of H2V3O8 nanowires (NWs) wrapped by graphene sheets and used as the cathode material for aqueous rechargeable zinc ion batteries is developed. Owing to the synergistic merits of desirable structural features of H2V3O8 NWs and high conductivity of the graphene network, the H2V3O8 NW/graphene composite exhibits superior zinc ion storage performance including high capacity of 394 mA h g−1 at 1/3 C, high rate capability of 270 mA h g−1 at 20 C and excellent cycling stability of up to 2000 cycles with a capacity retention of 87%. The battery offers a high energy density of 168 W h kg−1 at 1/3 C and a high power density of 2215 W kg−1 at 20 C (calculated based on the total weight of H2V3O8 NW/graphene composite and the theoretically required amount of Zn). Systematic structural and elemental characterization confirm the reversible Zn2+ and water cointercalation electrochemical reaction mechanism. This work brings a new prospect of designing high-performance aqueous rechargeable zinc ion batteries for grid-scale energy storage.

Polymer-Passivated Inorganic Cesium Lead Mixed-Halide Perovskites for Stable and Efficient Solar Cells with High Open-Circuit Voltage over 1.3 V.

Abstract: Cesium-based trihalide perovskites have been demonstrated as promising light absorbers for photovoltaic applications due to their superb composition stability. However, the large energy losses (Eloss ) observed in inorganic perovskite solar cells has become a major hindrance impairing the ultimate efficiency. Here, an effective and reproducible method of modifying the interface between a CsPbI2 Br absorber and polythiophene hole-acceptor to minimize the Eloss is reported. It is demonstrated that polythiophene, deposited on the top of CsPbI2 Br, can significantly reduce electron-hole recombination within the perovskite, which is due to the electronic passivation of surface defect states. In addition, the interfacial properties are improved by a simple annealing process, leading to significantly reduced energy disorder in polythiophene and enhanced hole-injection into the hole-acceptor. Consequently, one of the highest power conversion efficiency (PCE) of 12.02% from a reverse scan in inorganic mixed-halide perovskite solar cells is obtained. Modifying the perovskite films with annealing polythiophene enables an open-circuit voltage (VOC ) of up to 1.32 V and Eloss of down to 0.5 eV, which both are the optimal values reported among cesium-lead mixed-halide perovskite solar cells to date. This method provides a new route to further improve the efficiency of perovskite solar cells by minimizing the Eloss .

Coordination of Atomic Co-Pt Coupling Species at Carbon Defects as Active Sites for Oxygen Reduction Reaction.

Abstract: Platinum (Pt) is the state-of-the-art catalyst for oxygen reduction reaction (ORR), but its high cost and scarcity limit its large-scale use. However, if the usage of Pt reduces to a sufficiently low level, this critical barrier may be overcome. Atomically dispersed metal catalysts with high activity and high atom efficiency have the possibility to achieve this goal. Herein, we report a locally distributed atomic Pt-Co nitrogen–carbon-based catalyst (denoted as A-CoPt-NC) with high activity and robust durability for ORR (267 times higher than commercial Pt/C in mass activity). The A-CoPt-NC shows a high selectivity for the 4e– pathway in ORR, differing from the reported 2e– pathway characteristic of atomic Pt catalysts. Density functional theory calculations suggest that this high activity originates from the synergistic effect of atomic Pt-Co located on a defected C/N graphene surface. The mechanism is thought to arise from asymmetry in the electron distribution around the Pt/Co metal centers, as well as...

Design of Metal‐Free Polymer Carbon Dots: A New Class of Room‐Temperature Phosphorescent Materials

Abstract: Polymer carbon dots (PCDs) are proposed as a new class of room-temperature phosphorescence (RTP) materials. The abundant energy levels in PCDs increase the probability of intersystem crossing (ISC) and their covalently crosslinked framework structures greatly suppress the nonradiative transitions. The efficient methods allow the manufacture of PCDs with unique RTP properties in air without additional metal complexation or complicated matrix composition. They thus provide a route towards the rational design of metal-free RTP materials that may be synthesized easily. Furthermore, we find that RTP is associated with a crosslink-enhanced emission (CEE) effect, which provides further routes to design improved PCDs with diverse RTP performance. Our results show the potential of PCDs as a universal route to achieve effective metal-free RTP.

Efficient radical-based light-emitting diodes with doublet emission

Abstract: Organic light-emitting diodes (OLEDs)1–5, quantum-dot-based LEDs6–10, perovskite-based LEDs11–13 and micro-LEDs14,15 have been championed to fabricate lightweight and flexible units for next-generation displays and active lighting. Although there are already some high-end commercial products based on OLEDs, costs must decrease whilst maintaining high operational efficiencies for the technology to realise wider impact. Here we demonstrate efficient action of radical-based OLEDs16, whose emission originates from a spin doublet, rather than a singlet or triplet exciton. While the emission process is still spin-allowed in these OLEDs, the efficiency limitations imposed by triplet excitons are circumvented for doublets. Using a luminescent radical emitter, we demonstrate an OLED with maximum external quantum efficiency of 27 per cent at a wavelength of 710 nanometres—the highest reported value for deep-red and infrared LEDs. For a standard closed-shell organic semiconductor, holes and electrons occupy the highest occupied and lowest unoccupied molecular orbitals (HOMOs and LUMOs), respectively, and recombine to form singlet or triplet excitons. Radical emitters have a singly occupied molecular orbital (SOMO) in the ground state, giving an overall spin-1/2 doublet. If—as expected on energetic grounds—both electrons and holes occupy this SOMO level, recombination returns the system to the ground state, giving no light emission. However, in our very efficient OLEDs, we achieve selective hole injection into the HOMO and electron injection to the SOMO to form the fluorescent doublet excited state with near-unity internal quantum efficiency. Organic light-emitting devices containing radical emitters can achieve an efficiency of 27 per cent at deep-red and infrared wavelengths based on the excitation of spin doublets, rather than singlet or triplet states.

Corrosion engineering towards efficient oxygen evolution electrodes with stable catalytic activity for over 6000 hours

Abstract: Although a number of nonprecious materials can exhibit catalytic activity approaching (sometimes even outperforming) that of iridium oxide catalysts for the oxygen evolution reaction, their catalytic lifetimes rarely exceed more than several hundred hours under operating conditions. Here we develop an energy-efficient, cost-effective, scaled-up corrosion engineering method for transforming inexpensive iron substrates (e.g., iron plate and iron foam) into highly active and ultrastable electrodes for oxygen evolution reaction. This synthetic method is achieved via a desired corrosion reaction of iron substrates with oxygen in aqueous solutions containing divalent cations (e.g., nickel) at ambient temperature. This process results in the growth on iron substrates of thin film nanosheet arrays that consist of iron-containing layered double hydroxides, instead of rust. This inexpensive and simple manufacturing technique affords iron-substrate-derived electrodes possessing excellent catalytic activities and activity retention for over 6000 hours at 1000 mA cm-2 current densities.

MXene-Bonded Activated Carbon as a Flexible Electrode for High-Performance Supercapacitors

Abstract: We report a strategy to employ two-dimensional Ti3C2Tx MXene as a flexible, conductive, and electrochemically active binder for one-step fabrication of MXene-bonded activated carbon as a flexible electrode for supercapacitors in an organic electrolyte. In this electrode, the activated carbon particles are encapsulated between the MXene layers, eliminating the need for insulative polymer binders. MXene plays a multifunctional role in the electrode, including as a binder, a flexible backbone, a conductive additive, and an additional active material. The synergetic effect of MXene and activated carbon constructs a three-dimensional conductive network and enlarges the distance between the MXene layers, greatly enhancing the electrode capacitance and rate capability. As a result, the flexible MXene-bonded activated carbon electrode exhibits a high capacitance of 126 F g–1 at 0.1 A g–1 and a retention of 57.9% at 100 A g–1 in an organic electrolyte, which is required for developing high-performance, flexible su...

miRNAS in cardiovascular diseases: potential biomarkers, therapeutic targets and challenges

Abstract: Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality in the world. Although considerable progress has been made in the diagnosis, treatment and prognosis of CVD, there is still a critical need for novel diagnostic biomarkers and new therapeutic interventions to decrease the incidence of this disease. Recently, there is increasing evidence that circulating miRNAs (miRNAs), i.e. endogenous, stable, single-stranded, short, non-coding RNAs, can be used as diagnostic biomarkers for CVD. Furthermore, miRNAs represent potential novel therapeutic targets for several cardiovascular disorders. In this review we provides an overview of the effects of several CVD; including heart failure, acute myocardial infarction, arrhythmias and pulmonary hypertension; on levels of circulating miRNAs. In addition, the use of miRNA as therapeutic targets is also discussed, as well as challenges and recommendations in their use in the diagnosis of CVD.

The cost of Alzheimer's disease in China and re-estimation of costs worldwide

Abstract: Introduction The socioeconomic costs of Alzheimer's disease (AD) in China and its impact on global economic burden remain uncertain. Methods We collected data from 3098 patients with AD in 81 representative centers across China and estimated AD costs for individual patient and total patients in China in 2015. Based on this data, we re-estimated the worldwide costs of AD. Results The annual socioeconomic cost per patient was US $19,144.36, and total costs were US $167.74 billion in 2015. The annual total costs are predicted to reach US $507.49 billion in 2030 and US $1.89 trillion in 2050. Based on our results, the global estimates of costs for dementia were US $957.56 billion in 2015, and will be US $2.54 trillion in 2030, and US $9.12 trillion in 2050, much more than the predictions by the World Alzheimer Report 2015. Discussion China bears a heavy burden of AD costs, which greatly change the estimates of AD cost worldwide.

One-Step Hydrothermal Synthesis of Nitrogen-Doped Conjugated Carbonized Polymer Dots with 31% Efficient Red Emission for In Vivo Imaging.

Abstract: Carbon dots with long-wavelength emissions, high quantum yield (QY) and good biocompatibility are highly desirable for biomedical applications. Herein, a green, facile hydrothermal synthesis of highly efficient red emissive nitrogen-doped carbonized polymer dots (CPDs) with optimal emission at around 630 nm are reported. The red emissive CPDs possess a variety of superior properties including excellent water dispersibility, good biocompatibility, narrow bandwidth emission, an excitation-independent emission, and high QY (10.83% (in water) and 31.54% (in ethanol)). Further studies prove that such strong red fluorescence is ascribed to the efficient conjugated aromatic π systems and hydrogen bonds of CPDs. And the fluorescence properties of CPDs can be regulated by adjusting the dosage of HNO3 before the reaction. Additionally, the as-prepared CPDs are successfully used as a fluorescent probe for bioimaging, both in vitro and in vivo. More importantly, biodistribution results demonstrate that most CPDs and their metabolites are not only excreted in urine but also excreted by hepatobiliary system in a rapid manner. Besides, the CPDs could easily cross the blood brain barrier, which may provide a valuable strategy for the theranostics of some brain diseases through real-time tracking.

Polydopamine Nanoparticles as Efficient Scavengers for Reactive Oxygen Species in Periodontal Disease

Abstract: Antioxidative therapy has been considered an efficient strategy for the treatment of a series of excessive reactive oxygen species (ROS)-triggered diseases, including oxidative-stress-induced periodontal disease. However, current natural enzymes and nanozymes often show their high specificity toward given ROS and have insufficient antioxidative effects against multiple ROS generated in the diseases process. Meanwhile, multienzyme-based antioxidant defense systems are usually confined by the complicated synthesis as well as potential unwanted residue and toxicity. Various supports are highly needed to immobilize natural enzymes and antioxidants during the biorelated usages due to their low operational stability and difficulty of reuse. To overcome these limitations, we develop a high-performance platform by using biodegradable polydopamine nanoparticles (PDA NPs) as smart ROS scavengers in oxidative stress-induced periodontal disease. Although PDA-based materials are well-known to eliminate ROS both in vit...

Strategy of Solution-Processed All-Inorganic Heterostructure for Humidity/Temperature-Stable Perovskite Quantum Dot Light-Emitting Diodes.

Abstract: Recently, a pressing requirement of solid-state lighting sources with high performance and low cost has motivated increasing research in metal halide perovskites. However, the relatively low emission efficiency and poor operation stability of perovskite light-emitting diodes (LEDs) are still critical drawbacks. In this study, a strategy of solution-processed all-inorganic heterostructure was proposed to overcome the emission efficiency and operation stability issues facing the challenges of perovskite LEDs. Solution-processed n-ZnO nanoparticles and p-NiO are used as the carrier injectors to fabricate all-inorganic heterostructured CsPbBr3 quantum dot LEDs, and a high-efficiency green emission is achieved with maximum luminance of 6093.2 cd/m2, external quantum efficiency of 3.79%, and current efficiency of 7.96 cd/A. More importantly, the studied perovskite LEDs possess a good operation stability after a long test time in air ambient. Typically, the devices can endure a high humidity (75%, 12 h) and a hi...

Efficient oxygen evolution electrocatalysis in acid by a perovskite with face-sharing IrO 6 octahedral dimers

Abstract: The widespread use of proton exchange membrane water electrolysis requires the development of more efficient electrocatalysts containing reduced amounts of expensive iridium for the oxygen evolution reaction (OER). Here we present the identification of 6H-phase SrIrO3 perovskite (6H-SrIrO3) as a highly active electrocatalyst with good structural and catalytic stability for OER in acid. 6H-SrIrO3 contains 27.1 wt% less iridium than IrO2, but its iridium mass activity is about 7 times higher than IrO2, a benchmark electrocatalyst for the acidic OER. 6H-SrIrO3 is the most active catalytic material for OER among the iridium-based oxides reported recently, based on its highest iridium mass activity. Theoretical calculations indicate that the existence of face-sharing octahedral dimers is mainly responsible for the superior activity of 6H-SrIrO3 thanks to the weakened surface Ir-O binding that facilitates the potential-determining step involved in the OER (i.e., O* + H2O → HOO* + H+ + e¯). While splitting water may provide a renewable source of carbon-neutral energy, the water oxidation half-reaction is sluggish and the materials needed show poor stability. Here, authors demonstrate an unusual iridium-based oxide to perform high-efficiency oxygen evolution in acid with good stability.

Free Radical Damage in Ischemia-Reperfusion Injury: An Obstacle in Acute Ischemic Stroke after Revascularization Therapy.

Abstract: Acute ischemic stroke is a common cause of morbidity and mortality worldwide. Thrombolysis with recombinant tissue plasminogen activator and endovascular thrombectomy are the main revascularization therapies for acute ischemic stroke. However, ischemia-reperfusion injury after revascularization therapy can result in worsening outcomes. Among all possible pathological mechanisms of ischemia-reperfusion injury, free radical damage (mainly oxidative/nitrosative stress injury) has been found to play a key role in the process. Free radicals lead to protein dysfunction, DNA damage, and lipid peroxidation, resulting in cell death. Additionally, free radical damage has a strong connection with inducing hemorrhagic transformation and cerebral edema, which are the major complications of revascularization therapy, and mainly influencing neurological outcomes due to the disruption of the blood-brain barrier. In order to get a better clinical prognosis, more and more studies focus on the pharmaceutical and nonpharmaceutical neuroprotective therapies against free radical damage. This review discusses the pathological mechanisms of free radicals in ischemia-reperfusion injury and adjunctive neuroprotective therapies combined with revascularization therapy against free radical damage.

A content-based recommender system for computer science publications

Abstract: As computer science and information technology are making broad and deep impacts on our daily lives, more and more papers are being submitted to computer science journals and conferences. To help authors decide where they should submit their manuscripts, we present the Content-based Journals & Conferences Recommender System on computer science, as well as its web service at http://www.keaml.cn/prs/ . This system recommends suitable journals or conferences with a priority order based on the abstract of a manuscript. To follow the fast development of computer science and technology, a web crawler is employed to continuously update the training set and the learning model. To achieve interactive online response, we propose an efficient hybrid model based on chi-square feature selection and softmax regression. Our test results show that, the system can achieve an accuracy of 61.37% and suggest the best journals or conferences in about 5 s on average.

Synergistic and low adverse effect cancer immunotherapy by immunogenic chemotherapy and locally expressed PD-L1 trap.

Abstract: Although great success has been obtained in the clinic, the current immune checkpoint inhibitors still face two challenging problems: low response rate and immune-related adverse effects (irAEs). Here we report the combination of immunogenic chemotherapy and locally expressed PD-L1 trap fusion protein for efficacious and safe cancer immunotherapy. We demonstrate that oxaliplatin (OxP) boosts anti-PD-L1 mAb therapy against murine colorectal cancer. By design of a PD-L1 trap and loading its coding plasmid DNA into a lipid-protamine-DNA nanoparticle, PD-L1 trap is produced transiently and locally in the tumor microenvironment, and synergizes with OxP for tumor inhibition. Significantly, unlike the combination of OxP and anti-PD-L1 mAb, the combination of OxP and PD-L1 trap does not induce obvious Th17 cells accumulation in the spleen, indicating better tolerance and lower tendency to irAEs. The reports here may highlight the potential of applying PD-L1 inhibitor, especially locally expressed PD-L1 trap, in cancer therapy following OxP-based chemotherapy.