231 research outputs found

    Node Density Estimation in VANETs Using Received Signal Power

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    Accurately estimating node density in Vehicular Ad hoc Networks, VANETs, is a challenging and crucial task. Various approaches exist, yet none takes advantage of physical layer parameters in a distributed fashion. This paper describes a framework that allows individual nodes to estimate the node density of their surrounding network independent of beacon messages and other infrastructure-based information. The proposal relies on three factors: 1) a discrete event simulator to estimate the average number of nodes transmitting simultaneously; 2) a realistic channel model for VANETs environment; and 3) a node density estimation technique. This work provides every vehicle on the road with two equations indicating the relation between 1) received signal strength versus simultaneously transmitting nodes, and 2) simultaneously transmitting nodes versus node density. Access to these equations enables individual nodes to estimate their real-time surrounding node density. The system is designed to work for the most complicated scenarios where nodes have no information about the topology of the network and, accordingly, the results indicate that the system is reasonably reliable and accurate. The outcome of this work has various applications and can be used for any protocol that is affected by node density

    Psychological Analysis of Catharsis in the Field of Psychotherapy (By Emphasizing on the Counseling Theories)

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    The following article has focused on the role of emotional catharsis and the effectiveness of it in different theories of psychotherapy and counseling. Each of the theories has been examined based on their possibilities in the catharsis of five emotions: anger, sadness, fear, anxiety and hatred. Counselling is not giving advice and teaching information to the clients, but the possibility it provides for catharsis is the success factor of the treatment. In catharsis of the anger, therapy's primary emphasis is facilitating the client's development. But in the release of grief, the focus is on resolving personality conflicts. In releasing anxiety, the main purpose is to change behavior. In catharsis of the hatred, psychotherapy aims to adapt the client to the environment. This article examines counseling theories in terms of how they deal with the aforementioned five emotions. Psychotherapy is interactive, confidential, and humanitarian conversation. In this conversation, the client talks about the troubles, disturbances, pressures and discomforts. Clients express their feelings and thoughts, and the therapist tries to simplify the process of this retelling with specific methods appropriate to the client's situation and problem. Therefore, only the consultation based on catharsis carries out the treatment in the true sense

    Tuning the Photoexcitation Response of Cyanobacterial Photosystem I via Reconstitution into Proteoliposomes

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    The role of natural thylakoid membrane housing of Photosystem I (PSI), the transmembrane photosynthetic protein, in its robust photoactivated charge separation with near unity quantum efficiency is not fundamentally understood. To this end, incorporation of suitable protein scaffolds for PSI incorporation is of great scientific and device manufacturing interest. Areas of interest include solidstate bioelectronics, and photoelectrochemical devices that require bio-abio interfaces that do not compromise the photoactivity and photostability of PSI. Therefore, the surfactant-induced membrane solubilization of a negatively charged phospholipid (DPhPG) with the motivation of creating biomimetic reconstructs of PSI reconstitution in DPhPG liposomes is studied. Specifically, a simple yet elegant method for incorporation of PSI trimeric complexes into DPhPG bilayer membranes that mimic the natural thylakoid membrane housing of PSI is introduced. The efficacy of this method is demonstrated via absorption and fluorescence spectroscopy measurements as well as direct visualization using atomic force microscopy. This study provides direct evidence that PSI confinements in synthetic lipid scaffolds can be used for tuning the photoexcitation characteristics of PSI. Hence, it paves the way for development of fundamental understanding of microenvironment alterations on photochemical response of light activated membrane proteins

    An experimental approach to oxidative stress effect on sperm motility and DNA fragmentation

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    En el estudio de la fertilidad masculina en todas las especies animales, la movilidad espermática, junto a la concentración y morfometría son los parámetros principales y más básicos en la evaluación de la calidad de los espermatozoides. La infertilidad masculina habitualmente se asocia con tasas anormales de estos parámetros seminales. Aún teniendo, los espermatozoides tasas adecuadas de todos estos parámetros no se puede garantizar la capacidad de fertilizar y/o desarrollar un cigoto. Por lo tanto, está claro que el examen rutinario del semen y los espermatozoides en la eyaculación no puede evaluar otros parámetros importantes en el proceso de fecundación como es capacitación espermática o detectar la fragmentación del ADN o la disfunción mitocondrial de los espermatozoides. El ADN del esperma juega un papel crítico en el desarrollo normal del embrión ya que la información genética transmitida a la próxima generación depende de la integridad del ADN del esperma. Los trabajos de investigación de los que consta esta tesis se realizaron con el objetivo de utilizar modelos animales para esclarecer la mejor manera de medir la fragmentación del ADN de manera lo más objetiva posible, en muestras de semen y evaluar el efecto del estrés oxidativo sobre la viabilidad y motilidad de los espermatozoides. Para este fin, se realizaron cuatro experimentos, pero solo tres de ellos se presentan en este documento. En primer lugar, para establecer las condiciones de activación de los espermatozoides del pez, fue necesario estudiar el efecto de los medios de activación en un rango de osmolaridad y tiempo de almacenamiento y evaluar los parámetros de motilidad espermática a lo largo del tiempo en el pez cebra (Danio rerio). En el Experimento 2, se estudió cómo el H2O2, como uno de los agentes importantes del estrés oxidativo, podría afectar al nivel de fragmentación del ADN y la movilidad de los espermatozoides en el pez cebra. Sin embargo, las mediciones del área del halo de la cabeza del espermatozoide no estaban coincidentes con la tasa subjetiva de fragmentación del ADN espermático (SDF). En este sentido, se demostró, por primera vez, una evolución de la fragmentación del ADN utilizando criterios morfométricos en esperma humano (Experimento 3). El experimento final (Experimento 4) se incluye como un resumen extendido en el Anexo 2. En este experimento, se usaron machos cabríos de Murciano-Granadina para evaluar la correlación entre las condiciones de conservación de semen refrigerado y la integridad del ADN, nivel de oxidación y actividad mitocondrial en espermatozoides utilizando la tecnología de citometría de flujo para su evaluación. Los resultados del Experimento 1 mostraron como la tasa de movilidad de los espermatozoides era más elevada y que su duración se prolongaba cuando la activación se realizaba en el medio de activación con la osmolalidad más alta. Con respecto a los parámetros cinéticos, observamos que casi todos los parámetros de velocidad (VCL, VSL y VAP) aumentaron significativamente en un medio con la osmolalidad alta. La movilidad total y los valores de velocidad de los espermatozoides fueron significativamente menores después de su conservación a 4 ° C durante 24 h. Respecto al Experimento 2, observamos que la movilidad de los espermatozoides de pez cebra, principalmente la movilidad progresiva, disminuyó a medida que aumentaba el H2O2. Por otra parte, la SDF aumentó a medida que aumentaba la concentración de H2O2. Sin embargo, las mediciones del área de halo no concordaron con la tasa subjetiva de SDF. El uso de una prueba de SCD (dispersión de cromatina de esperma) es una forma habitual para determinar el nivel de SDF en las células. Esta prueba se basó en el uso de la presencia de halo para la evaluación de SDF. Finalmente, en el Experimento 3, demostramos que la expansión real del halo es una variable continua que no se puede reducir a un valor discreto por elección. Las cadenas de ADN de la cromatina espermática están altamente condensadas por las protaminas. En mamíferos, las cromatinas contienen una estructura altamente organizada y compactada aún más que otras especies o espermatozoides humanos.In the study of male fertility in all species, the first and most basic parameters in sperm quality is its motility, count and morphology and how to maintain these important factors as a viable spermatozoon. Male infertility is usually associated with the presence of abnormal semen parameters. Spermatozoa with adequate rates of all these functional parameters could still be not able to fertilize and/or develop a zygote. Thus, it is clear that routine examination of the semen and the spermatozoa in the ejaculate cannot assess the process of capacitation or detect the DNA fragmentation or sperm mitochondrial dysfunction. Sperm DNA plays a critical role in normal embryo development as the genetic information passed on to the next generation depends on sperm DNA integrity. The research for this thesis was performed with the aim of using animal models to find the best way to measure DNA fragmentation in semen samples and evaluate the effect of oxidative stress on the viability and motility of spermatozoa. To this end, four experiments were performed, but only three of them are presented in this document. Firstly, in order to establish fish sperm activation conditions, it was necessary to study the effect of activation media in a range of osmolality and storage time and evaluate sperm motility parameters over time in zebrafish (Danio rerio). In Experiment 2, demonstrated how H2O2, as one the important oxidative stress agents, could affect the DNA fragmentation level and motility of zebrafish sperm. However, measurements of the halo area did not agree with the subjective sperm DNA fragmentation (SDF) rate. In this sense, it demonstrated, for the first time, an evolution of DNA fragmentation using morphometric criteria in human sperm (Experiment 3). The final experiment (Experiment 4) is included as an extended abstract in the Annexe 2. In this experiment, the Murciano-Granadina male goats were used to evaluate the correlation between semen cooled conservation conditions and DNA integrity, oxidation level, and mitochondrial activity in sperm using flow cytometry technologies. The results of Experiment 1 demonstrated that the sperm motility rate was higher and the duration was prolonged with the activation medium with the highest osmolality. With regard to kinetic sperm parameters, we observed almost all the velocity parameters (VCL, VSL and VAP) increased significantly in a high osmolality medium. Total motility and velocity values of sperm were significantly lower after cool storage at 4°C for 24 h. With regard to Experiment 2, we observed the motility of zebrafish sperm, mainly progressive motility, decreased as H2O2 increased. Moreover, SDF increased as the H2O2 concentration increased. However, measurements of the halo area did not agree with the subjective SDF rate. Using a SCD (sperm chromatin dispersion) test is a common way to determine the SDF level in cells. This test was based on using the presence of halo for SDF evaluation. Finally, in Experiment 3, we demonstrated that the actual expansion of the halo is a continuous variable that cannot be reduced to one discrete value by choice. The DNA strands of sperm chromatin are highly condensed by protamines. In some mammals, chromatins contain a highly organised and compact structure which is more compact than the other species or human sperm

    Purification of mitochondrial RNase P in A. nidulans

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    Résumé La ribonucléase P (RNase P) est une ribonucléoprotéine omniprésente dans tous les règnes du vivant, elle est responsable de la maturation en 5’ des précurseurs des ARNs de transfert (ARNts) et quelques autres petits ARNs. L’enzyme est composée d'une sous unité catalytique d'ARN (ARN-P) et d'une ou de plusieurs protéines selon les espèces. Chez les eucaryotes, l’activité de la RNase P cytoplasmique est distincte de celles des organelles (mitochondrie et chloroplaste). Chez la plupart des espèces, les ARN-P sont constituées de plusieurs éléments structuraux secondaires critiques conservés au cours de l’évolution. En revanche, au niveau de la structure, une réduction forte été observé dans la plupart des mtARN-Ps. Le nombre de protéines composant la RNase P est extrêmement variable : une chez les bactéries, environ quatre chez les archéobactéries, et dix chez la forme cytoplasmique des eucaryotes. Cet aspect est peu connu pour les formes mitochondriales. Dans la plupart des cas, l’identification de la mtRNase P est le résultat de longues procédures de purification comprenant plusieurs étapes dans le but de réduire au minimum le nombre de protéines requises pour l’activité (exemple de la levure et A. nidulans). Cela mène régulièrement à la perte de l’activité et de l’intégrité des complexes ribonucléo-protéiques natifs. Dans ce travail, par l’utilisation de la technique de BN-PAGE, nous avons développé une procédure d’enrichissement de l’activité RNase P mitochondriale native, donnant un rendement raisonnable. Les fractions enrichies capables de cette activité enzymatique ont été analysées par LC/MS/MS et les résultats montrent que l’holoenzyme de la RNase P de chacune des fractions contient un nombre de protéines beaucoup plus grand que ce qui était connue. Nous suggérons une liste de protéines (principalement hypothétiques) qui accompagnent l’activité de la RNase P. IV De plus, la question de la localisation de la mtRNase P de A. nidulans a été étudiée, selon nos résultats, la majorité de la mtRNase P est attachée á la membrane interne de la mitochondrie. Sa solubilisation se fait par l’utilisation de différents types de détergent. Ces derniers permettent l’obtention d’un spectre de complexes de la RNase P de différentes tailles.Abstract RNase P is a ribonucleo-protein complex (an RNA enzyme or ribozyme) that cleaves 5’ leader sequences of precursor tRNAs and a few other small RNAs. It occurs in all three domains of life, Bacteria, Archaea and Eukarya, with the latter containing distinct nuclear and organellar (mitochondrial or plastid) activities. In most instances, the complex contains a single, well-conserved RNA subunit that carries the active center of the enzyme. Yet, compare to bacterial and nuclear P RNA, most mtP RNAs are structurally highly reduced. The number of P proteins is highly variable: one in Bacteria, about four in Archaea, and ten in the cytoplasmic form of Eukarya. Much less is known in the case of mitochondria. MtRNase P is usually purified by using numerous separation steps that include unphysiological conditions, leading to complexes having a minimum number of subunits (e.g., in yeast and Aspergillus nidulans), that often loose their activity. Here, using BN PAGE, we have developed an enrichment procedure for A. nidulans mtRNase P that avoids some of the most disruptive conditions. The protein composition of active fractions was identified with LC/MS/MS, indicating that the RNase P holoenzyme is much larger than previously thought. Finally, the question of mtRNase P localization within mitochondria was investigated, by tracing its RNA subunit by RT PCR. We found that mtRNase P of A. nidulans is a predominantly membrane-attached enzyme; it is in part solubilized by detergents such as digitonin and Triton

    Localization and function of the endocannabinoid system throughout the retinogeniculate pathway of vervet monkeys

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    Le système endocannabinoïde (eCB) est présent dans le système nerveux central (SNC) de mammifères, incluant la rétine, et est responsable de la régulation de nombreux processus physiologiques. Bien que la présence du récepteur cannabinoïde de type 1 (CB1R) a bien été documenté dans la rétine de rongeurs et primates, il y a encore une controverse quant à la présence du récepteur cannabinoïde de type 2 (CB2R) au niveau du SNC. En utilisant la microscopie confocale, nous sommes les premiers à signaler les patrons d’expression du CB2R dans la rétine de singe. Nos résultats démontrent que le CB2R est exprimé exclusivement dans les cellules de Müller de la rétine du singe. En outre, nous avons comparé les différents patrons d’expression du système eCB dans la rétine de la souris, du toupaye, ainsi que du singe vervet et macaque. Nous rapportons que les distributions de CB1R, FAAH (fatty acid amid hydrolase), MAGL (monoacylglycerol lipase) et DAGLα (diacylglycerol lipase alpha) sont hautement conservées parmi ces espèces alors que CB2R et NAPE-PLD (N-acyl phosphatidylethanolamine phospholipase D) présentent différents profils d'expression. CB2R n'a pas été détecté dans les cellules neuronales de la rétine des primates. L’immunoréactivité de NAPE-PLD est présente dans les couches de la rétine de souris et toupayes, mais a été limitée à la couche des photorécepteurs des singes vervet et macaque. Pour étudier les corrélats neuronaux et le rôle de la signalisation du système eCB dans la rétine, nous avons établi un protocole standard pour l'électrorétinographie (ERG), puis enregistré la réponse ERG de la rétine après le blocage des récepteurs avec des antagonistes spécifiques pour CB1R (AM251) et CB2R (AM630). Comparé au témoin, dans des conditions photopiques, et à certaines intensités faibles du stimulus, le blocage de CB1R diminue l'amplitude de l'onde-b, alors qu’à des intensités plus élevées, le blocage de CB2R augmente l'amplitude des deux-ondes a et b. De plus, le blocage des récepteurs cannabinoïdes provoque une augmentation de la latence des deux ondes a et b. Dans des conditions d’adaptation à l'obscurité, le blocage de CB1R et CB2R réduit l’amplitudes de l'onde a seulement à des intensités plus élevées et réduit l’onde b à intensités plus faibles. Des augmentations significatives de latence ont été observées dans les deux cas. Ces résultats indiquent que les récepteurs CB1 et CB2 chez les primates non humains sont impliqués dans la fonction rétinienne conditions photopiques. En outre, nous avons évalué le profil d'expression du CB1R, de FAAH et de NAPE-PLD au-delà de la rétine dans le corps géniculé latéral des singes et nous rapportons pour la première fois que CB1R et FAAH sont exprimés davantage dans les couches magnocellulaires. La NAPE-PLD a été localisée à travers les couches magno- et parvocellulaires. Aucune de ces composantes n’est exprimée dans les couches koniocellulaires. Ces résultats nous aident à mieux comprendre les effets des cannabinoïdes sur le système visuel qui pourraient nous mener à trouver éventuellement de nouvelles cibles thérapeutiques.The endocannabinoid (eCB) system is present in the mammalian central nervous system, including the retina, and is responsible for the regulation of many physiological processes. Anatomical and functional data collected in the retina indicate that cannabinoid receptors are important mediators of retinal function. Although the presence of the cannabinoid receptor type 1 (CB1R) has been documented in the rodent and primate retina, there is still some controversy regarding the presence of the CB2 receptor (CB2R) within the central nervous system. By using confocal microscopy, we are the first to report the distribution patterns of CB2R in the monkey retina. Our results show that CB2R is expressed exclusively in the Müller cells of the primate retina. Furthermore, we compared the eCB system distribution patterns in the retinas of mice, tree shrews, and vervet and macaque monkeys. We report that CB1R, FAAH, MAGL, and DAGLα distributions are highly conserved among these 3 species whereas CB2R and NAPE-PLD exhibit different expression patterns. CB2R was not detected in the neuroretinal cells of primates. NAPE-PLD immunoreactivity was present in the retinal layers of mice and tree shrews but was restricted to the photoreceptor layer in both species of primates studied. To study the neural correlates and the role of eCB signaling in the retina, we first established a standard protocol for electroretinography (ERG) and then recorded the ERG response of the retina after blocking receptors with specific antagonists for CB1R (AM251) and CB2R (AM630). Compare to control, in photopic conditions, at certain low flash intensities, only the blockade of CB1R decreases the amplitude of the a-wave and b-wave, while at some high flash intensities, blockade of CB2R increase the amplitude of both a- and b-waves. Also the blockade of the cannabinoid receptors causes an increase in the latency of both a- and b-waves. In dark-adapted eyes, blockade of the CB1R and CB2R reduces the a-wave only amplitudes in the higher intensities and decrease the b-wave in lower intensities. Some significant increases in latency were observed in both cases. These results indicate that CB1 and CB2 receptors in primates are involved in retinal function under photopic and scotopic conditions. In addition, we assessed the expression pattern of eCB components CB1R, FAAH, and NAPE-PLD beyond the retina in the dorsal lateral geniculate nucleus (dLGN) of primates and report for the first time that while CB1R and FAAH are more abundantly expressed in the magnocellular layer, NAPE-PLD is distributed throughout both the magno- and parvocellular layers. None of these components are expressed in the koniocellular layer. These findings augment our understanding of the effects of cannabinoids on the visual system and may lead to novel therapeutics targeted to eCB signaling

    Dynamics of Individual Molecules of Linear Polyethylene Liquids under Shear: Atomistic Simulation and Comparison with a Free-draining Bead-rod Chain

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    Nonequilibrium molecular dynamics (NEMD) simulations of a dense liquid composed of linear polyethylene chains were performed to investigate the chain dynamics under shear. Brownian dynamics (BD) simulations of a freely jointed chain with equivalent contour length were also performed in the case of a dilute solution. This allowed for a close comparison of the chain dynamics of similar molecules for two very different types of liquids. Both simulations exhibited a distribution of the end-to-end vector, |Rete|, with Gaussian behavior at low Weissenberg number (Wi). At high Wi, the NEMD distribution was bimodal, with two peaks associated with rotation and stretching of the individual molecules. BD simulations of a dilute solution did not display a bimodal character; distributions of |Rete| ranged from tightly coiled to fully stretched configurations. The simulations revealed a tumbling behavior of the chains and correlations between the components of Rete exhibited characteristic frequencies of tumbling, which scaled as Wi−0.75. Furthermore, after a critical Wi of approximately 2, another characteristic time scale appeared which scaled as Wi−0.63. Although the free-draining solution is very different than the dense liquid, the BD simulations revealed a similar behavior, with the characteristic time scales mentioned above scaling as Wi−0.68 and Wi−0.66

    Key Components of Antenatal Lifestyle Interventions to Optimize Gestational Weight Gain: Secondary Analysis of a Systematic Review

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    Importance: Randomized clinical trials have found that antenatal lifestyle interventions optimize gestational weight gain (GWG) and pregnancy outcomes. However, key components of successful interventions for implementation have not been systematically identified. Objective: To evaluate intervention components using the Template for Intervention Description and Replication (TIDieR) framework to inform implementation of antenatal lifestyle interventions in routine antenatal care. Data Sources: Included studies were drawn from a recently published systematic review on the efficacy of antenatal lifestyle interventions for optimizing GWG. The Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Health Technology Assessment Database, MEDLINE, and Embase were searched from January 1990 to May 2020. Study Selection: Randomized clinical trials examining efficacy of antenatal lifestyle interventions in optimizing GWG were included. Data Extraction and Synthesis: Random effects meta-analyses were used to evaluate the association of intervention characteristics with efficacy of antenatal lifestyle interventions in optimizing GWG. The results are reported according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses reporting guideline. Data extraction was performed by 2 independent reviewers. Main Outcomes and Measures: The main outcome was mean GWG. Measures included characteristics of antenatal lifestyle interventions comprising domains related to theoretical framework, material, procedure, facilitator (allied health staff, medical staff, or researcher), delivery format (individual or group), mode, location, gestational age at commencement (<20 wk or ≥20 wk), number of sessions (low [1-5 sessions], moderate [6-20 sessions], and high [≥21 sessions]), duration (low [1-12 wk], moderate [13-20 wk], and high [≥21 wk]), tailoring, attrition, and adherence. For all mean differences (MDs), the reference group was the control group (ie, usual care). Results: Overall, 99 studies with 34546 pregnant individuals were included with differential effective intervention components found according to intervention type. Broadly, interventions delivered by an allied health professional were associated with a greater decrease in GWG compared with those delivered by other facilitators (MD, -1.36 kg; 95% CI, -1.71 to -1.02 kg; P <.001). Compared with corresponding subgroups, dietary interventions with an individual delivery format (MD, -3.91 kg; 95% CI -5.82 to -2.01 kg; P =.002) and moderate number of sessions (MD, -4.35 kg; 95% CI -5.80 to -2.89 kg; P <.001) were associated with the greatest decrease in GWG. Physical activity and mixed behavioral interventions had attenuated associations with GWG. These interventions may benefit from an earlier commencement and a longer duration for more effective optimization of GWG. Conclusions and Relevance: These findings suggest that pragmatic research may be needed to test and evaluate effective intervention components to inform implementation of interventions in routine antenatal care for broad public health benefit.

    Hybrid Nanocomposites of Nanostructured Co3O4 Interfaced with Reduced/Nitrogen-Doped Graphene Oxides for Selective Improvements in Electrocatalytic and/or Supercapacitive Properties

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    Performance enhancements in next-generation electrochemical energy storage/conversion devices require the design of new classes of nanomaterials that exhibit unique electrocatalytic and supercapacitive properties. To this end, we report the use of laser ablation synthesis in solution (LASiS) operated with cobalt as the target in graphene oxide (GO) solution in tandem with two different post treatments to manufacture three kinds of hybrid nanocomposites (HNCs) namely, (1) Co3O4 nanoparticle (NP)/reduced graphene oxide (rGO), (2) Co3O4 nanorod (NR)/rGO, and (3) Co3O4 NP/nitrogen-doped graphene oxide (NGO). FTIR and Raman spectroscopic studies indicate that both chemical and charge driven interactions are partially responsible for embedding the Co3O4 NPs/NRs into the various GO films. We tune the selective functionalities of the as-synthesized HNCs as oxygen reduction reaction (ORR) catalysts and/or supercapacitors by tailoring their structure–property relationships. Specifically, the nitrogen doping in the NP/NGO HNC samples promotes higher electron conductivity while hindering aggregation between 0D CoO NPs that are partially reshaped into Co3O4 nanocubes due to induced surface strain energies. Our results indicate that such interfacial energetics and arrangements lead to superior ORR electrocatalytic activities. On the other hand, the interconnecting 1D nanostructures in theNR/rGO HNCs benefit charge transport and electrolyte diffusion at the electrode–electrolyte interfaces, thereby promoting their supercapacitive properties. The NP/rGO HNCs exhibit intermediate functionalities towards both ORR catalysis and supercapacitance
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