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In motor neuroscience, state changes are hypothesized to time-lock neural assemblies coordinating complex movements, but evidence for this remains slender. We tested whether a discrete change from more autonomous to coherent spiking underlies skilled movement by imaging cerebellar Purkinje neuron complex spikes in mice making targeted forelimb-reaches. As mice learned the task, millimeter-scale spatiotemporally coherent spiking emerged ipsilateral to the reaching forelimb, and consistent neural synchronization became predictive of kinematic stereotypy. Before reach onset, spiking switched from more disordered to internally time-locked concerted spiking and silence. Optogenetic manipulations of cerebellar feedback to the inferior olive bi-directionally modulated neural synchronization and reaching direction. A simple model explained the reorganization of spiking during reaching as reflecting a discrete bifurcation in olivary network dynamics. These findings argue that to prepare learned movements, olivo-cerebellar circuits enter a self-regulated, synchronized state promoting motor coordination. State changes facilitating behavioral transitions may generalize across neural systems.
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Movimiento/fisiología , Red Nerviosa/fisiología , Potenciales de Acción/fisiología , Animales , Calcio/metabolismo , Cerebelo/fisiología , Sincronización Cortical , Miembro Anterior/fisiología , Interneuronas/fisiología , Aprendizaje , Ratones Endogámicos C57BL , Ratones Transgénicos , Modelos Neurológicos , Actividad Motora/fisiología , Núcleo Olivar/fisiología , Optogenética , Células de Purkinje/fisiología , Conducta Estereotipada , Análisis y Desempeño de TareasRESUMEN
Electrophysiological field potential dynamics are of fundamental interest in basic and clinical neuroscience, but how specific cell types shape these dynamics in the live brain is poorly understood. To empower mechanistic studies, we created an optical technique, TEMPO, that records the aggregate trans-membrane voltage dynamics of genetically specified neurons in freely behaving mice. TEMPO has >10-fold greater sensitivity than prior fiber-optic techniques and attains the noise minimum set by quantum mechanical photon shot noise. After validating TEMPO's capacity to track established oscillations in the delta, theta, and gamma frequency bands, we compared the D1- and D2-dopamine-receptor-expressing striatal medium spiny neurons (MSNs), which are interspersed and electrically indistinguishable. Unexpectedly, MSN population dynamics exhibited two distinct coherent states that were commonly indiscernible in electrical recordings and involved synchronized hyperpolarizations across both MSN subtypes. Overall, TEMPO allows the deconstruction of normal and pathologic neurophysiological states into trans-membrane voltage activity patterns of specific cell types.
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Ondas Encefálicas , Ratones/fisiología , Neurofisiología/métodos , Imagen de Colorante Sensible al Voltaje/métodos , Animales , Femenino , Masculino , Ratones Endogámicos BALB CRESUMEN
Graphene nanoribbons (GNRs) are widely recognized as intriguing building blocks for high-performance electronics and catalysis owing to their unique width-dependent bandgap and ample lone pair electrons on both sides of GNR, respectively, over the graphene nanosheet counterpart. However, it remains challenging to mass-produce kilogram-scale GNRs to render their practical applications. More importantly, the ability to intercalate nanofillers of interest within GNR enables in-situ large-scale dispersion and retains structural stability and properties of nanofillers for enhanced energy conversion and storage. This, however, has yet to be largely explored. Herein, we report a rapid, low-cost freezing-rolling-capillary compression strategy to yield GNRs at a kilogram scale with tunable interlayer spacing for situating a set of functional nanomaterials for electrochemical energy conversion and storage. Specifically, GNRs are created by sequential freezing, rolling, and capillary compression of large-sized graphene oxide nanosheets in liquid nitrogen, followed by pyrolysis. The interlayer spacing of GNRs can be conveniently regulated by tuning the amount of nanofillers of different dimensions added. As such, heteroatoms; metal single atoms; and 0D, 1D, and 2D nanomaterials can be readily in-situ intercalated into the GNR matrix, producing a rich variety of functional nanofiller-dispersed GNR nanocomposites. They manifest promising performance in electrocatalysis, battery, and supercapacitor due to excellent electronic conductivity, catalytic activity, and structural stability of the resulting GNR nanocomposites. The freezing-rolling-capillary compression strategy is facile, robust, and generalizable. It renders the creation of versatile GNR-derived nanocomposites with adjustable interlay spacing of GNR, thereby underpinning future advances in electronics and clean energy applications.
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The electrochemical reduction of CO2 into value-added chemicals has been explored as a promising solution to realize carbon neutrality and inhibit global warming. This involves utilizing the electrochemical CO2 reduction reaction (CO2RR) to produce a variety of single-carbon (C1) and multi-carbon (C2+) products. Additionally, the electrolyte solution in the CO2RR system can be enriched with nitrogen sources (such as NO3-, NO2-, N2, or NO) to enable the synthesis of organonitrogen compounds via C-N coupling reactions. However, the electrochemical conversion of CO2 into valuable chemicals still faces challenges in terms of low product yield, poor faradaic efficiency (FE), and unclear understanding of the reaction mechanism. This review summarizes the promising strategies aimed at achieving selective production of diverse carbon-containing products, including CO, formate, hydrocarbons, alcohols, and organonitrogen compounds. These approaches involve the rational design of electrocatalysts and the construction of coupled electrocatalytic reaction systems. Moreover, this review presents the underlying reaction mechanisms, identifies the existing challenges, and highlights the prospects of the electrosynthesis processes. The aim is to offer valuable insights and guidance for future research on the electrocatalytic conversion of CO2 into carbon-containing products of enhanced value-added potential.
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The shuttling of polysulfides on the cathode and the uncontrollable growth of lithium dendrites on the anode have restricted the practical application of lithium-sulfur (Li-S) batteries. In this study, a metal-coordinated 3D covalent organic framework (COF) with a homogeneous distribution of nickel-bis(dithiolene) and N-rich triazine centers (namely, NiS4-TAPT) was designed and synthesized, which can serve as bifunctional hosts for both sulfur cathodes and lithium anodes in Li-S batteries. The abundant Ni centers and N-sites in NiS4-TAPT can greatly enhance the adsorption and conversion of the polysulfides. Meanwhile, the presence of Ni-bis(dithiolene) centers enables uniform Li nucleation at the Li anode, thereby suppressing the growth of Li dendrites. This work demonstrated the effectiveness of integrating catalytic and adsorption sites to optimize the chemical interactions between host materials and redox-active intermediates, potentially facilitating the rational design of metal-coordinated COF materials for high-performance secondary batteries.
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Aqueous redox flow batteries (ARFBs) hold great potential for large-scale energy storage. Recently, research on aqueous flow batteries has shifted toward water-soluble organic molecules with redox capabilities to reduce the use of mineral resources. The chemical and electrochemical stabilities of organic compounds are heavily influenced by their functional groups and reaction sites. In this study, we present a low-cost synthesis of the O-alkyl-carboxylate-functionalized derivatives of 2,3-dihydroxyphenazine, namely, phenazine-(2,3-diyl) dioxy dibutyric acid (DBEP) and phenazine-(2,3-diyl)dioxy diacetic acid (DAEP), which serve as negolytes and exhibit good reversibility and high redox kinetics. The evidence is provided to clarify the capacity degradation mechanisms of DAEP and DBEP by a series of comprehensive characterizations. Similar to anthraquinones functionalized with alkyl chains, the main degradation mechanism of DAEP modified with acetic acid is due to side chain loss. Longer side chains are more stable and can withstand long-term electrochemical reactions. DBEP modified with butyric acid exhibits superior chemical and electrochemical stability. Our results demonstrate that rational molecular design and suitable membranes, such as the alkaline ARFBs based on DBEP negolyte, potassium ferrocyanide (K4Fe(CN)6) posolyte, and custom sulfonated poly(ether ether ketone) membrane, can deliver a high open-circuit voltage of 1.17 V and high capacity retention of 99.997% per cycle for over 1000 cycles at 50 mA cm-2. This study highlights the importance of not only considering the modification position of the molecules but also focusing on the influence of various side chains on the redox core's stability toward sustainable grid-scale energy storage applications.
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The electrocatalytic nitrate reduction reaction (NITRR) holds great promise for purifying wastewater and producing valuable ammonia (NH3). However, the lack of efficient electrocatalysts has impeded the achievement of highly selective NH3 synthesis from the NITRR. In this study, we report the design and synthesis of two polynuclear Co-cluster-based coordination polymers, {[Co2(TCPPDA)(H2O)5]·(H2O)9(DMF)} and {Co1.5(TCPPDA)[(CH3)2NH2]·(H2O)6(DMF)2} (namely, NJUZ-2 and NJUZ-3), which possess distinct coordination motifs with well-defined porosity, high-density catalytic sites, accessible mass transfer channels, and nanoconfined chemical environments. Benefitting from their intriguing multicore metal-organic coordination framework structures, NJUZ-2 and NJUZ-3 exhibit remarkable catalytic activities for the NITRR. At a potential of -0.8 V (vs. RHE) in an H-type cell, they achieve an optimal Faradaic efficiency of approximately 98.5% and high long-term durability for selective NH3 production. Furthermore, the electrocatalytic performance is well maintained even under strongly acidic conditions. When operated under an industrially relevant current density of 469.9 mA cm-2 in a flow cell, a high NH3 yield rate of up to 3370.6 mmol h-1 g-1cat. was observed at -0.5 V (vs. RHE), which is 20.1-fold higher than that obtained in H-type cells under the same conditions. Extensive experimental analyses, in combination with theoretical computations, reveal that the great enhancement of the NITRR activity is attributed to the preferential adsorption of NO3- and the reduction in energy input required for the hydrogenation of *NO3 and *NO2 intermediates.
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Aqueous rechargeable magnesium batteries hold immense potential for intrinsically safe, cost-effective, and sustainable energy storage. However, their viability is constrained by a narrow voltage range and suboptimal compatibility between the electrolyte and electrodes. Herein, we introduce an innovative ternary deep eutectic Mg-ion electrolyte composed of MgCl2·6H2O, acetamide, and urea in a precisely balanced 1:1:7 molar ratio. This formulation was optimized by leveraging competitive solvation effects between Mg2+ ions and two organic components. The full batteries based on this ternary eutectic electrolyte, Mn-doped sodium vanadate (Mn-NVO) anode, and copper hexacyanoferrate cathode exhibited an elevated voltage plateau and high rate capability and showcased stable cycling performance. Ex-situ characterizations unveiled the Mg2+ storage mechanism of Mn-NVO involving initial extraction of Na+ followed by subsequent Mg2+ intercalation/deintercalation. Detailed spectroscopic analyses illuminated the formation of a pivotal solid-electrolyte interphase on the anode surface. Moreover, the solid-electrolyte interphase demonstrated a dynamic adsorption/desorption behavior, referred to as the "breathing effect", which substantially mitigated undesired dissolution and side reactions of electrode materials. These findings underscore the crucial role of rational electrolyte design in fostering the development of a favorable solid-electrolyte interphase that can significantly enhance compatibility between electrode materials and electrolytes, thus propelling advancements in aqueous multivalent-ion batteries.
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Mucin glycoproteins are a significant source of carbon for the gut bacteria. Various gut microbial species possess diverse hydrolytic enzymes and catabolic pathways for breaking down mucin glycans, resulting in competition for the limited nutrients within the gut environment. Adherence to mucin glycans represents a crucial strategy used by gut microbes to access nutrient reservoirs. Understanding these properties is pivotal for comprehending the survival mechanisms of bacteria in the gastrointestinal tract. However, characterization of individual strains within the vast array of coexisting bacteria in the microbiome is challenging. To investigate this, we developed mucin-immobilized particles by immobilizing porcine gastric mucin (PGM) onto glass beads chemically modified with boronic acid. These PGM-immobilized particles were then anaerobically cultured with human fecal microbiota, and the bacteria adhering to PGM were isolated. Interestingly, the microbiome composition remained largely unchanged irrespective of PGM immobilization. Nonetheless, bacteria isolated from PGM-immobilized glass particles exhibited notably higher N-acetylgalactosaminidase activity compared to the control beads. Furthermore, Bacteroides strains isolated from PGM-immobilized glass particles displayed enhanced adhesive and metabolic properties to PGM. These findings underscore the utility of PGM particles in enriching and isolating specific microbes. Moreover, they highlight substantial differences in microbial properties at the strain level. We anticipate that PGM-immobilized particles will advance culture-based microbiome research, emphasizing the significance of strain-level characterization. IMPORTANCE: Metabolism of mucin glycans by gut bacteria represents a crucial strategy for accessing nutrient reservoirs. The efficacy of mucin glycan utilization among gut bacteria hinges on the metabolic capabilities of individual strains, necessitating meticulous strain-level characterization. In this investigation, we used glass beads chemically immobilized with mucins to selectively enrich bacteria from fecal fermentation cultures, based on their superior adhesion to and metabolism of mucin glycoproteins. These findings lend support to the hypothesis that the physical interactions between bacteria and mucin glycoprotein components directly correlate with their capacity to utilize mucins as nutrient sources. Furthermore, our study implies that physical proximity may significantly influence bacterial nutrient acquisition within the ecosystem, facilitating gut bacteria's access to carbohydrate components.
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Advancements in cost-effective, high-performance alkaline water-splitting systems are crucial for the hydrogen industry. While the significance of electrode material design has been widely acknowledged, the practical implementation of these advancements remains challenging. In this study, we focused on the holistic design of the electrolysis system and successfully developed a novel alkaline water-splitting electrolyzer. The unique configuration of our electrolyzer allows the designed NiFe-LDH/carbon cloth gas diffusion anode to interact solely with the PVA-based gel membrane and air, enabling the direct discharge of oxygen into the gas phase. This innovative feature accelerates anode bubble overflow, reduces gas interference, and decreases the system impedance by minimizing electrode spacing. As a result, by utilizing the NiFeSn-alloy/nickel mesh cathode, our electrolyzer achieves a high current density of 308 mA cm-2 at a cell voltage of 2.0 V and demonstrates exceptional stability over 1000 h.
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BACKGROUND: Accompanied by the growing prevalence of nonalcoholic fatty liver disease (NAFLD), the coexistence of chronic hepatitis B (CHB) and NAFLD has increased. In the context of CHB, there is limited understanding of the factors that influence the development of NASH. METHODS: We enrolled CHB combined NAFLD patients who had liver biopsy and divided them to NASH vs. non-NASH groups. A whole transcriptome chip was used to examine the expression profiles of long noncoding RNAs (lncRNAs) and mRNA in biopsied liver tissues. The function analysis of HIGD1A were performed. We knocked down or overexpressed HIGD1A in HepG2.2.15 cells by transient transfection of siRNA-HIGD1A or pcDNA-HIGD1A. In vivo investigations were conducted using hepatitis B virus (HBV) transgenic mice. RESULTS: In 65 patients with CHB and NAFLD, 28 were patients with NASH, and 37 were those without NASH. After screening 582 differentially expressed mRNAs, GO analysis revealed differentially expressed mRNAs acting on nicotinamide adenine dinucleotide phosphate (NADPH), which influenced redox enzyme activity. KEGG analysis also shown that they were involved in the NAFLD signaling pathway. The function analysis revealed that HIGD1A was associated with the mitochondrion. Then, both in vivo and in vitro CHB model, HIGD1A was significantly higher in the NASH group than in the non-NASH group. HIGD1A knockdown impaired mitochondrial transmembrane potential and induced cell apoptosis in HepG2.2.15 cells added oleic acid and palmitate. On the contrary, hepatic HIGD1A overexpression ameliorated free fatty acids-induced apoptosis and oxidative stress. Furthermore, HIGD1A reduced reactive oxygen species (ROS) level by increasing glutathione (GSH) expression, but Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK)/Acetyl-CoA carboxylase (ACC) pathway was not involved. CONCLUSION: Both in vivo and in vitro CHB model, an upward trend of HIGD1A was observed in the NASH-related inflammatory response. HIGDIA played a protective role in cells against oxidative stress. Our data suggested that HIGD1A may be a positive regulator of NASH within the CHB context.
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Hepatitis B Crónica , Enfermedad del Hígado Graso no Alcohólico , Ratones , Animales , Humanos , Enfermedad del Hígado Graso no Alcohólico/patología , Hepatitis B Crónica/complicaciones , Hígado/patología , Virus de la Hepatitis B/genética , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Sulfinamides are a versatile class of compounds that find applications in both organic synthesis and pharmaceuticals. Here we developed an efficient photocatalytic approach for the convenient preparation of sulfinamides. Commercially available potassium trifluoro(organo)borates and readily available sulfinyl amines are rationally used and converted to a series of alkyl or aryl sulfinamides in moderate to high yields. The reaction allows for the gram-scale preparation of sulfinamides. Moreover, sulfonimidamides, sulfonimidate esters and sulfonyl amides could be obtained in one pot.
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Loss of dopamine in Parkinson's disease is hypothesized to impede movement by inducing hypo- and hyperactivity in striatal spiny projection neurons (SPNs) of the direct (dSPNs) and indirect (iSPNs) pathways in the basal ganglia, respectively. The opposite imbalance might underlie hyperkinetic abnormalities, such as dyskinesia caused by treatment of Parkinson's disease with the dopamine precursor L-DOPA. Here we monitored thousands of SPNs in behaving mice, before and after dopamine depletion and during L-DOPA-induced dyskinesia. Normally, intermingled clusters of dSPNs and iSPNs coactivated before movement. Dopamine depletion unbalanced SPN activity rates and disrupted the movement-encoding iSPN clusters. Matching their clinical efficacy, L-DOPA or agonism of the D2 dopamine receptor reversed these abnormalities more effectively than agonism of the D1 dopamine receptor. The opposite pathophysiology arose in L-DOPA-induced dyskinesia, during which iSPNs showed hypoactivity and dSPNs showed unclustered hyperactivity. Therefore, both the spatiotemporal profiles and rates of SPN activity appear crucial to striatal function, and next-generation treatments for basal ganglia disorders should target both facets of striatal activity.
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Dopamina/metabolismo , Discinesias/patología , Discinesias/fisiopatología , Neuronas/metabolismo , Trastornos Parkinsonianos/patología , Trastornos Parkinsonianos/fisiopatología , Animales , Señalización del Calcio , Dopamina/deficiencia , Discinesias/etiología , Discinesias/metabolismo , Femenino , Levodopa/metabolismo , Levodopa/farmacología , Masculino , Ratones , Modelos Biológicos , Movimiento/efectos de los fármacos , Neostriado/metabolismo , Neostriado/patología , Neostriado/fisiopatología , Trastornos Parkinsonianos/metabolismo , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/metabolismoRESUMEN
PURPOSE: To develop a deep learning model to accurately detect anterior cruciate ligament (ACL) ruptures on magnetic resonance imaging (MRI) and to evaluate its effect on the diagnostic accuracy and efficiency of clinicians. METHODS: A training dataset was built from MRIs acquired from January 2017 to June 2021, including patients with knee symptoms, irrespective of ACL ruptures. An external validation dataset was built from MRIs acquired from January 2021 to June 2022, including patients who underwent knee arthroscopy or arthroplasty. Patients with fractures or prior knee surgeries were excluded in both datasets. Subsequently, a deep learning model was developed and validated using these datasets. Clinicians of varying expertise levels in sports medicine and radiology were recruited, and their capacities in diagnosing ACL injuries in terms of accuracy and diagnosing time were evaluated both with and without artificial intelligence (AI) assistance. RESULTS: A deep learning model was developed based on the training dataset of 22,767 MRIs from 5 centers and verified with external validation dataset of 4,086 MRIs from 6 centers. The model achieved an area under the receiver operating characteristic curve of 0.987 and a sensitivity and specificity of 95.1%. Thirty-eight clinicians from 25 centers were recruited to diagnose 3,800 MRIs. The AI assistance significantly improved the accuracy of all clinicians, exceeding 96%. Additionally, a notable reduction in diagnostic time was observed. The most significant improvements in accuracy and time efficiency were observed in the trainee groups, suggesting that AI support is particularly beneficial for clinicians with moderately limited diagnostic expertise. CONCLUSIONS: This deep learning model demonstrated expert-level diagnostic performance for ACL ruptures, serving as a valuable tool to assist clinicians of various specialties and experience levels in making accurate and efficient diagnoses. LEVEL OF EVIDENCE: Level III, retrospective comparative case series.
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Lesiones del Ligamento Cruzado Anterior , Aprendizaje Profundo , Humanos , Lesiones del Ligamento Cruzado Anterior/diagnóstico por imagen , Lesiones del Ligamento Cruzado Anterior/cirugía , Ligamento Cruzado Anterior , Estudios Retrospectivos , Inteligencia Artificial , Imagen por Resonancia Magnética/métodosRESUMEN
The genus Passiflora, commonly known as passion fruit, originated in South America, is an economically important horticulture crop and widely distributed in the tropics and subtropics. Yellow passion fruit (Passiflora edulis f. flavicarpa) and purple passion fruit (Passiflora edulis f. edulis) are the two most planted species (Santos-Jiménez et al., 2022), which have been largely cultivated in southern China. The average annual production reaches 600,000 tons, of which yellow fruit accounts for more than 70% (Zhou et al., 2022). In 2022 to 2023, a disease caused flower rot severely in passion fruit plantations. The incidence rate was generally 10% in purple passion fruit, with an incidence up to 60% in yellow passion fruit 'Qinmi No. 9'. Flower rot occurs mainly in the rainy season, especially during periods of prolonged rain. Infected flowers had black patches that were water-soaked on the interior of the flower bud. The patches covered the entire flower bud, and fluffy mycelium and sporangia developed, which caused the flower bud rotten and abscised easily. Five symptomatic flowers from Wuhua, Guangdong (23°23'N, 115°18'E) and 8 symptomatic flowers from Shangsi, Guangxi (21°15'N, 107°98'E) of 'Qinmi No. 9' were collected during flowering period in 2022 and 2023. Diseased flower pieces were surface-sterilized with 70% ethanol for 2 to 3 min, rinsed with sterile distilled water 3 times, and placed on PDA medium at 25â in darkness. Four and 6 fungal isolates with similar morphology were isolated from the infected samples of Wuhua and Shangsi, respectively. Two isolates, PRFJ01 from Wuhua and PRGX02 from Shangsi, were randomly selected for further study. Purified fungal colonies at the age of 3 days accompany with diffuse cottony mycelia, turned white to gray later. The mycelia were hyaline and aseptate. Sporangiophores with 0.56 (0.22~1.10) mm in length and 6.1 (3.18~10.87) µm in width (n=100) were erect, light brown, and had rhizoids and stolons at their bases. Sporangia with 48.0 (23.45~92.85) µm in diameter (n=100) were dark-colored, near spherical and having dark ovoid sporangiospores with 3.56 (2.34~6.39) µm × 2.82 (1.73~4.70) µm (n=100). The morphology of the fungus were identical to Rhizopus stolonifer (Ehrenb.) Vuill (Haque et al. 2023). The two isolates were molecularly identified using genomic regions of 28S large ribosomal subunit (LSU) with NL1 and LR3 primers (Cruz-Lachica et al., 2018). The phylogenetic trees revealed the sequences of PRFJ01 (OR801560.1) and PRGX02 (OR801561.1) were 100% and 99% identical to R. stolonifer (MK705761.1 and KC412868.1), respectively. Pathogenicity tests were conducted on healthy flowers and leaves of 5-month-old grafted 'Qinmi No. 9' plants. Mycelial plugs with 5-mm diameter were placed on the flowers and leaves. Three plants were performed for each of the isolates, and the test was repeated twice. The inoculated plants were moisturized with plastic bags. Healthy flowers and leaves inoculated with sterile PDA plugs were used as control. Typical symptoms were observed on inoculated plants after 2 days. The dark grey mycelia and sporangia covered the entire flower after 4 days inoculation. The flower bud became putrid and the flower stalk split off. Lesions on leaves expanded accompany with numerous aerial mycelium. However, the controls were symptomless. R. stolonifer was reisolated from inoculated tissues. Previously, flower rot on passion fruit caused by R. stolonifer has only been recorded in Brazil (Ploetz, 2003). To our knowledge, this is the first report of R. stolonifer causing flower rot on passion fruit in China.
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The conversion of CO2 to high-value products by renewable energy is a promising approach for realizing carbon neutralization, but the selectivity and efficiency of C2+ products are not satisfying. Herein, we report the controllable preparation of highly ordered mesoporous cobalt oxides with modulated surface states to achieve efficient photothermal water-steam reforming of CO2 to C2 products with high activity and tunable selectivity. Pristine mesoporous Co3O4 exhibited an acetic acid selectivity of 96% with a yield rate of 73.44 µmol g-1 h-1. By rationally modifying mesoporous Co3O4 surface states, mesoporous Co3O4@CoO delivered a radically altered â¼100% ethanol selectivity with a yield rate of 14.85 µmol g-1 h-1. Comprehensive experiments revealed that the pH value could strongly influence the selectivity of C2 products over mesoporous cobalt oxides. Density functional theory verified that reduced surface states and rich oxygen vacancies on surface-modified mesoporous cobalt oxides could facilitate further variation of C2 products from acetic acid to ethanol.
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Two-dimensional (2D) bismuthene is predicted to possess intriguing physical properties, but its preparation remains challenging due to the high surface energy constraint. Herein, we report a sandwiched epitaxy growth strategy for the controllable preparation of 2D bismuthene between a Cu foil substrate and a h-BN covering layer. The top h-BN layer plays a crucial role in suppressing the structural transformation of bismuthene and compensating for the charge transfer from the bismuthene to the Cu(111) surface. The bismuthene nanoflakes present a superior thermal stability up to 500 °C in air, attributed to the passivation effect of the h-BN layer. Moreover, the bismuthene nanoflakes demonstrate an ultrahigh faradaic efficiency of 96.3% for formate production in the electrochemical CO2 reduction reaction, which is among the highest reported for Bi-based electrocatalysts. This study offers a promising approach to simultaneously synthesize and protect 2D bismuthene nanoflakes, which can be extended to other 2D materials with a high surface energy.
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Zinc-iodine (Zn-I2) batteries have garnered significant attention for their high energy density, low cost, and inherent safety. However, several challenges, including polyiodide dissolution and shuttling, sluggish iodine redox kinetics, and low electrical conductivity, limit their practical applications. Herein, we designed a highly efficient electrocatalyst for Zn-I2 batteries by uniformly dispersing Ni single atoms (NiSAs) on hierarchical porous carbon skeletons (NiSAs-HPC). In situ Raman analysis revealed that the conversion of soluble polyiodides (I3- and I5-) was significantly accelerated using NiSAs-HPC because of the remarkable electrocatalytic activity of NiSAs. The resulting Zn-I2 batteries with NiSAs-HPC/I2 cathodes delivered exceptional rate capability (121 mAh g-1 at 50 C), and ultralong cyclic stability (over 40â¯000 cycles at 50 C). Even under 11.6 mg cm-2 iodine, Zn-I2 batteries still exhibited an impressive cyclic stability with a capacity retention of 93.4% and 141 mAh g-1 after 10â¯000 cycles at 10 C.
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Electrochemical conversion of CO2 into high-value-added chemicals has been considered a promising route to achieve carbon neutrality and mitigate the global greenhouse effect. However, the lack of highly efficient electrocatalysts has limited its practical application. Herein, we propose an ultrafast and green electric explosion method to batch-scale prepare spherical indium (In) nanocrystals (NCs) with abundant metal defects toward high selective electrocatalytic CO2 reduction (CO2RR) to HCOOH. During the electric explosion synthesis process, the Ar atmosphere plays a significant role in forming the spherical In NCs with abundant metal defects instead of highly crystalline In2O3 NCs formed under an air atmosphere. Analysis results reveal that the In NCs possess ultrafast catalytic kinetics and reduced onset potential, which is ascribed to the formation of rich metal defects serving as effective catalytic sites for converting CO2 into HCOOH. This work provides a feasible strategy to massively produce efficient In-based electrocatalysts for electrocatalytic CO2-to-formate conversion.
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Massive production of practical metal or alloy based electrocatalysts for electrocatalytic CO2 reduction reaction is usually limited by energy-extensive consumption, poor reproducibility, and weak adhesion on electrode substrates. Herein, we report the ultrafast thermal shock synthesis and porosity engineering of free-standing Cu-Bi bimetallic nanofoam electrocatalysts with 3D hierarchical porous structure and easily adjustable compositions. During the thermal shock process, the rapid heating and cooling steps in several seconds result in strong interaction between metal nanopowders to form multiphase nanocrystallines with abundant grain boundaries and metastable CuBi intermetallic phase. The subsequent porosity engineering process via acid etching and electroreduction creates highly porous Cu-Bi structures that can increase electrochemically active surface area and facilitate mass/charge transfer. Among the Cu-Bi nanofoam electrodes with different Cu/Bi ratios, the Cu4Bi nanofoam exhibited the highest formate selectivity with a Faradaic efficiency of 92.4% at -0.9 V (vs reversible hydrogen electrode) and demonstrated excellent operation stability.