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Developing robust non-platinum electrocatalysts with multifunctional active sites for pH-universal hydrogen evolution reaction (HER) is crucial for scalable hydrogen production through electrochemical water splitting. Here ultra-small ruthenium-nickel alloy nanoparticles steadily anchored on reduced graphene oxide papers (Ru-Ni/rGOPs) as versatile electrocatalytic materials for acidic and alkaline HER are reported. These Ru-Ni alloy nanoparticles serve as pH self-adaptive electroactive species by making use of in situ surface reconstruction, where surface Ni atoms are hydroxylated to produce bifunctional active sites of Ru-Ni(OH)2 for alkaline HER, and selectively etched to form monometallic Ru active sites for acidic HER, respectively. Owing to the presence of Ru-Ni(OH)2 multi-site surface, which not only accelerates water dissociation to generate reactive hydrogen intermediates but also facilitates their recombination into hydrogen molecules, the self-supported Ru90Ni10/rGOP hybrid electrode only takes overpotential of as low as ≈106 mV to deliver current density of 1000 mA cm-2, and maintains exceptional stability for over 1000 h in 1 m KOH. While in 0.5 m H2SO4, the Ru90Ni10/rGOP hybrid electrode exhibits acidic HER catalytic behavior comparable to commercially available Pt/C catalyst due to the formation of monometallic Ru shell. These electrochemical behaviors outperform some of the best Ru-based catalysts and make it attractive alternative to Pt-based catalysts toward highly efficient HER.
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Aqueous aluminum-ion batteries are attractive post-lithium battery technologies for large-scale energy storage in virtue of abundant and low-cost Al metal anode offering ultrahigh capacity via a three-electron redox reaction. However, state-of-the-art cathode materials are of low practical capacity, poor rate capability, and inadequate cycle life, substantially impeding their practical use. Here layered manganese oxide that is pre-intercalated with benzoquinone-coordinated aluminum ions (BQ-AlxMnO2) as a high-performance cathode material of rechargeable aqueous aluminum-ion batteries is reported. The coordination of benzoquinone with aluminum ions not only extends interlayer spacing of layered MnO2 framework but reduces the effective charge of trivalent aluminum ions to diminish their electrostatic interactions, substantially boosting intercalation/deintercalation kinetics of guest aluminum ions and improving structural reversibility and stability. When coupled with Zn50Al50 alloy anode in 2 m Al(OTf)3 aqueous electrolyte, the BQ-AlxMnO2 exhibits superior rate capability and cycling stability. At 1 A g-1, the specific capacity of BQ-AlxMnO2 reaches ≈300 mAh g-1 and retains ≈90% of the initial value for more than 800 cycles, along with the Coulombic efficiency of as high as ≈99%, outperforming the AlxMnO2 without BQ co-incorporation.
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We construct a compartmentalized nanoarchitecture to regulate bioenergy level. Glucose dehydrogenase, urease and nicotinamide adenine dinucleotide are encapsulated inside through liquid-liquid phase separation. ATPase and glucose transporter embedded in hybrid liposomes are attached at the surface. Glucose is transported and converted to gluconic acid catalyzed by glucose dehydrogenase, resulting in an outward proton gradient to drive ATPase for ATP synthesis. In parallel, urease catalyzes hydrolysis of urea to generate ammonia, which leads to an inward proton gradient to drive ATPase for ATP hydrolysis. These processes lead to a change of the direction of proton gradient, thus achieving artificial ATP oscillation. Importantly, the frequency and the amplitude of the oscillation can be programmed. The work explores nanoarchitectonics integrating multiple components to realize artificial and precise oscillation of bioenergy level.
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Enhanced bioenergy anabolism through transmembrane redox reactions in artificial systems remains a great challenge. Here, we explore synthetic electron shuttle to activate transmembrane chemo-enzymatic cascade reactions in a mitochondria-like nanoarchitecture for augmenting bioenergy anabolism. In this nanoarchitecture, a dendritic mesoporous silica microparticle as inner compartment possesses higher load capacity of NADH as proton source and allows faster mass transfer. In addition, the outer compartment ATP synthase-reconstituted proteoliposomes. Like natural enzymes in the mitochondrion respiratory chain, a small synthetic electron shuttle embedded in the lipid bilayer facilely mediates transmembrane redox reactions to convert NADH into NAD+ and a proton. These facilitate an enhanced outward proton gradient to drive ATP synthase to rotate for catalytic ATP synthesis with improved performance in a sustainable manner. This work opens a new avenue to achieve enhanced bioenergy anabolism by utilizing a synthetic electron shuttle and tuning inner nanostructures, holding great promise in wide-range ATP-powered bioapplications.
Assuntos
NAD , Prótons , NAD/metabolismo , Elétrons , Trifosfato de Adenosina/metabolismo , Mitocôndrias/metabolismo , Transporte de ElétronsRESUMO
Metallic zinc is a promising anode material for rechargeable aqueous multivalent metal-ion batteries due to its high capacity and low cost. However, the practical use is always beset by severe dendrite growth and parasitic side reactions occurring at anode/electrolyte interface. Here we demonstrate dynamic molecular interphases caused by trace dual electrolyte additives of D-mannose and sodium lignosulfonate for ultralong-lifespan and dendrite-free zinc anode. Triggered by plating and stripping electric fields, the D-mannose and lignosulfonate species are alternately and reversibly (de-)adsorbed on Zn metal, respectively, to accelerate Zn2+ transportation for uniform Zn nucleation and deposition and inhibit side reactions for high Coulombic efficiency. As a result, Zn anode in such dual-additive electrolyte exhibits highly reversible and dendrite-free Zn stripping/plating behaviors for >6400â hours at 1â mA cm-2, which enables long-term cycling stability of Zn||ZnxMnO2 full cell for more than 2000â cycles.
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Precise segmentation of breast tumors from MRI is crucial for breast cancer diagnosis, as it allows for detailed calculation of tumor characteristics such as shape, size, and edges. Current segmentation methodologies face significant challenges in accurately modeling the complex interrelationships inherent in multi-sequence MRI data. This paper presents a hybrid deep network framework with three interconnected modules, aimed at efficiently integrating and exploiting the spatial-temporal features among multiple MRI sequences for breast tumor segmentation. The first module involves an advanced multi-sequence encoder with a densely connected architecture, separating the encoding pathway into multiple streams for individual MRI sequences. To harness the intricate correlations between different sequence features, we propose a sequence-awareness and temporal-awareness method that adeptly fuses spatial-temporal features of MRI in the second multi-scale feature embedding module. Finally, the decoder module engages in the upsampling of feature maps, meticulously refining the resolution to achieve highly precise segmentation of breast tumors. In contrast to other popular methods, the proposed method learns the interrelationships inherent in multi-sequence MRI. We justify the proposed method through extensive experiments. It achieves notable improvements in segmentation performance, with Dice Similarity Coefficient (DSC), Intersection over Union (IoU), and Positive Predictive Value (PPV) scores of 80.57%, 74.08%, and 84.74% respectively.
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Aqueous zinc-ion batteries are attractive post-lithium battery technologies for grid-scale energy storage because of their inherent safety, low cost and high theoretical capacity. However, their practical implementation in wide-temperature surroundings persistently confronts irregular zinc electrodeposits and parasitic side reactions on metal anode, which leads to poor rechargeability, low Coulombic efficiency and short lifespan. Here, this work reports lamellar nanoporous Cu/Al2Cu heterostructure electrode as a promising anode host material to regulate high-efficiency and dendrite-free zinc electrodeposition and stripping for wide-temperatures aqueous zinc-ion batteries. In this unique electrode, the interconnective Cu/Al2Cu heterostructure ligaments not only facilitate fast electron transfer but work as highly zincophilic sites for zinc nucleation and deposition by virtue of local galvanic couples while the interpenetrative lamellar channels serving as mass transport pathways. As a result, it exhibits exceptional zinc plating/stripping behaviors in aqueous hybrid electrolyte of diethylene glycol dimethyl ether and zinc trifluoromethanesulfonate at wide temperatures ranging from 25 to -30 °C, with ultralow voltage polarizations at various current densities and ultralong lifespan of >4000 h. The outstanding electrochemical properties enlist full cell of zinc-ion batteries constructed with nanoporous Cu/Al2Cu and ZnxV2O5/C to maintain high capacity and excellent stability for >5000 cycles at 25 and -30 °C.
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Constructing well-defined active multisites is an effective strategy to break linear scaling relationships to develop high-efficiency catalysts toward multiple-intermediate reactions. Here, dual-intermetallic heterostructure composed of tungsten-bridged Co3W and WNi4 intermetallic compounds seamlessly integrated on hierarchical nanoporous nickel skeleton is reported as a high-performance nonprecious electrocatalyst for alkaline hydrogen evolution and oxidation reactions. By virtue of interfacial tungsten atoms configuring contiguous multisites with proper adsorptions of hydrogen and hydroxyl intermediates to accelerate water dissociation/combination and column-nanostructured nickel skeleton facilitating electron and ion/molecule transportations, nanoporous nickel-supported Co3W-WNi4 heterostructure exhibits exceptional hydrogen electrocatalysis in alkaline media, with outstanding durability and impressive catalytic activities for hydrogen oxidation reaction (geometric exchange current density of ≈6.62 mA cm-2) and hydrogen evolution reaction (current density of ≈1.45 A cm-2 at overpotential of 200 mV). Such atom-ordered intermetallic heterostructure alternative to platinum group metals shows genuine potential for hydrogen production and utilization in hydroxide-exchange-membrane water electrolyzers and fuel cells.
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@#[摘 要] 目的:探究miR-323a-3p、四次穿膜蛋白超家族成员1(TM4SF1)在NSCLC组织和细胞中的表达及两者间的靶向调控关系,观察两者表达对A549细胞增殖、迁移、侵袭和裸鼠移植瘤生长的影响。方法:收集2014年1月至12月间青海省人民医院手术切除的20例NSCLC组织及其相应的癌旁组织,qPCR和WB法检测癌组织中miR-323a-3p、TM4SF1 mRNA 和TM4SF1蛋白的表达。向A549细胞转染miR-323a-3p mimic,采用MTT法、Transwell法、WB法检测miR-323a-3p过表达对细胞的增殖、迁移和侵袭以及TM4SF1、细胞周期蛋白D1(cyclin D1)、p21、MMP-2、MMP-9蛋白表达的影响。采用生物信息学预测工具StarBase和双荧光素酶报告基因实验分析miR-323a-3p与TM4SF1靶向关系。将si-TM4SF1转染至A549细胞,以及分别将miR-323a-3p mimic与pcDNA或pcDNA-TM4SF1共转染A549细胞,评估细胞增殖、迁移和侵袭能力的变化;同时建立各组细胞的BALB/c裸鼠移植瘤模型,在14、21和28 d时测量并计算移植瘤体积。结果:与癌旁组织相比,NSCLC组织中miR-323a-3p表达水平明显下调,TM4SF1 mRNA和蛋白表达水平显著上调(均P<0.01)。miR-323a-3p过表达或抑制TM4SF1表达都会降低A549 细胞的增殖、迁移、侵袭能力及cyclin D1、MMP-2、MMP-9蛋白表达而促进p21蛋白表达,并且抑制A549细胞裸鼠移植瘤的生长(均P<0.01)。生物信息学StarBase工具预测和双荧光素酶基因报告实验结果显示miR-323a-3p能够靶向结合TM4SF1基因并调控 TM4SF1的表达。上调TM4SF1表达后,miR-323a-3p过表达对A549细胞恶性生物学行为及cyclin D1、MMP-2、MMP-9蛋白表达、移植瘤生长的抑制作用均被部分逆转(均P<0.01),对p21蛋白表达的促进作用也被逆转(P<0.01)。结论:miR-323a-3p 通过靶向下调肺癌A549细胞中TM4SF1的表达抑制细胞的增殖、迁移、侵袭和裸鼠移植瘤生长。