Potassium oxonate, a selectively competitive uricase inhibitor, produced hyperuricemia (HUA) in rodents in a previous study. In this study, we employed the tree shrew as an animal model to study ...potassium oxonate-induced HUA. The effect of allopurinol (ALLO), a uric acid reducer, was also examined in this model. Potassium oxonate at doses of 5, 20, 40, 60, 80, 100, and 1,000 mg/kg was given intraperitoneally to tree shrews. The results showed that potassium oxonate can effectively increase the levels of uric acid in tree shrews at doses ranging from 40 to 100 mg/kg. Semiquantitative RT-PCR showed that the xanthine dehydrogenase/oxidase (XDH/XO) mRNA expression level was significantly higher in the liver tissue of tree shrews with high levels of uric acid. There were no changes in serum urea nitrogen, or serum creatinine values. ALLO can significantly decrease serum uric acid levels (P<0.01) and raise XDH/XO mRNA expression levels in the liver tissue of tree shrews with HUA. XDH/XO mRNA expression levels did not change in untreated tree shrews. Studies on acute toxicity in the tree shrew did not show any significantly abnormal signs. There were no adverse effects at the macroscopic level up to doses ≤100 mg/kg. Potassium oxonate induced acute HUA in tree shrews at lower doses compared with other animal models. Potassium oxonate-treated tree shrews may be a potential animal model for studying pathogenic mechanism and evaluating a new therapeutic agent for treatment of HUA in humans.
Identification of influential spreaders is still a challenging issue in network science. Therefore, it attracts increasing attention from both computer science and physical societies, and many ...algorithms to identify influential spreaders have been proposed so far. Degree centrality, as the most widely used neighborhood-based centrality, was introduced into the network world to evaluate the spreading ability of nodes. However, degree centrality always assigns too many nodes with the same value, so it leads to the problem of resolution limitation in distinguishing the real influences of these nodes, which further affects the ranking efficiency of the algorithm. The k-shell decomposition method also faces the same problem. In order to solve the resolution limit problem, we propose a high-resolution index combining both degree centrality and the k-shell decomposition method. Furthermore, based on the proposed index and the well-known gravity law, we propose an improved gravity model to measure the importance of nodes in propagation dynamics. Experiments on ten real networks show that our model outperforms most of the state-of-the-art methods. It has a better performance in terms of ranking performance as measured by the Kendall's rank correlation, and in terms of ranking efficiency as measured by the monotonicity value.
Circular RNAs (circRNAs) have a covalently closed circular conformation and are structurally stable. Those circRNAs with tumor‐suppressive properties play an important role in tumorigenesis and ...metastasis and thus may be used as therapeutic targets of cancers. Herein, we review the current understanding of the classification of circRNAs and summarize the functions and mechanisms of circRNAs that have tumor‐suppressive roles in various cancers, including liver cancer (circARSP91, circADAMTS13, circADAMTS14, circMTO1, hsa_circ_0079299, and circC3P1), bladder cancer (circFNDC3B, circITCH, circHIPK3, circRNA‐3, cdrlas, and circLPAR1), gastric cancer (circLARP4, circYAP1, hsa_cric_0000096, hsa_circ_0000993, and circPSMC3), breast cancer (circ_000911, hsa_circ_0072309, and circASS1), lung cancer (hsa_circ_0000977, circPTK2, circ_0001649, hsa_circ_100395, and circ_0006916), glioma (circ_0001946, circSHPRH, and circFBXW7), and colorectal cancer (circITGA7 and hsa_circ_0014717). Thanks to their structural stability, these tumor‐suppressive circRNAs may be used as potential and potent therapeutic targets. Moreover, we propose a new method for the classification of circRNAs. Based on whether they can be translated, circRNAs can be divided into noncoding circRNAs and coding circRNAs.
Tumor‐suppressive circRNAs may be used as potential and potent therapeutic targets. Moreover, we can propose a new method for the classification of circRNAs: based on whether they can be translated, circRNAs can be divided into noncoding circRNAs and coding circRNAs.
Self-powered implantable medical electronic devices that harvest biomechanical energy from cardiac motion, respiratory movement and blood flow are part of a paradigm shift that is on the horizon. ...Here, we demonstrate a fully implanted symbiotic pacemaker based on an implantable triboelectric nanogenerator, which achieves energy harvesting and storage as well as cardiac pacing on a large-animal scale. The symbiotic pacemaker successfully corrects sinus arrhythmia and prevents deterioration. The open circuit voltage of an implantable triboelectric nanogenerator reaches up to 65.2 V. The energy harvested from each cardiac motion cycle is 0.495 μJ, which is higher than the required endocardial pacing threshold energy (0.377 μJ). Implantable triboelectric nanogenerators for implantable medical devices offer advantages of excellent output performance, high power density, and good durability, and are expected to find application in fields of treatment and diagnosis as in vivo symbiotic bioelectronics.
Though it becomes a routine to fit impedance data to an equivalent electric circuit model (EECM) using complex nonlinear least square (CNLS) to extract physical parameters from impedance data, two ...formidable challenges still remain: to build a physically meaningful EECM and to find good initial estimates for model parameters. In this study, combining graphical analysis of impedance data in both Bode and Nyquist plots, a two-step procedure is proposed to address the challenges: (1) a frequency derivative phase angle method is developed in Bode plot to identify the number of time constants (or electrochemical processes); (2) graphical analysis of impedance data in Nyquist plot is used sequentially for initial parameter determination. Major graphical analysis methods are compared in terms of frequency resolution, accuracy and complexity using synthetic data. The superiority of the proposed procedure is illustrated using the experimental data of a three-electrode lithium-ion cell.
•Major graphical methods in both Bode and Nyquist plots are presented.•A frequency derivative phase angle method is developed for process identification.•Graphical analysis of Nyquist plot is enhanced for parameter estimation.•A complete graphical procedure is developed for robust analysis of impedance data.
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•A procedure to pretreat electrocatalysts to study the ammonia oxidation is provided.•Nads and O/OHads were identified as the major deactivation species that prevent ammonia ...oxidatoin.•The electrocatalytic activity, thermodynamics, and possible deactivation mechanisms for ammonia oxidation were elucidated.•The onset potential for ammonia oxidation is related to the hydrogen binding energy of the catalyst.•Ammonia electro-oxidation involves a complex decoupled electron and proton transfer process.
The ammonia electro-oxidation reaction (AOR) has been studied due to its promising applications in ammonia electrolysis, wastewater remediation, direct ammonia fuel cells, and sensors. However, it is difficult to compare and analyze the reported electrocatalytic activity of AOR reliably, likely due to the variation in catalyst synthesis, electrode composition, electrode morphology, and testing protocol. In this paper, the electro-oxidation of ammonia on different carbon-supported precious metal nanoparticle catalysts was revisited. The effect of experimental conditions, electrochemical test parameters, electrocatalytic activity, thermodynamics, and possible deactivation mechanism of the catalysts were investigated. Pt/C catalyst possesses the highest electrocatalytic activity, while Ir/C and Rh/C show lower overpotential. The onset potential of the AOR is related to the hydrogen binding energy of the catalyst. Nads is one major cause of deactivation accompanied with the formation of surface O/OHads at high potentials. The coulombic efficiency of Nads formation on Pt is about 1% initially and gradually decreases with reaction time. Increase in ammonia concentration leads to increase in current density, while increase in hydroxyl ions concentration can enhance the current density and reduce the overpotential simultaneously. The slopes of AOR onset potential and hydrogen adsorption/desorption potential of Pt/C as a function of pH follow Nernst equation. In contrast, potentials measured at different current densities exhibit non-Nernstian behavior, suggesting a critical role of the local pH change.
Major aspects related to lithium deposition in lithium-ion and lithium metal secondary batteries are reviewed. For lithium-ion batteries with carbonaceous anode, lithium deposition may occur under ...harsh charging conditions such as overcharging or charging at low temperatures. The major technical solutions include: (1) applying electrochemical models to predict the critical conditions for deposition initiation; (2) preventions by improved battery design and material modification; (3) applying adequate charging protocols to inhibit lithium deposition. For lithium metal secondary batteries, the lithium deposition is the inherent reaction during charging. The major technical solutions include: (1) the use of mechanistic models to elucidate and control dendrite initiation and growth; (2) engineering surface morphology of the lithium deposition to avoid dendrite formation via adjusting the composition and concentration of the electrolyte; (3) controlling battery working conditions. From a survey of the literature, the areas that require further study are proposed; e.g., refining the lithium deposition criteria, developing an effective AC self pre-heating method for low-temperature charging of lithium-ion batteries, and clarifying the role the solid electrolyte interphase (SEI) plays in determining the deposition morphology; to facilitate a refined control of the lithium deposition.
•A review of major aspects on lithium deposition in lithium-ion and lithium metal batteries.•Review of the deposition criteria and models that predict the occurrence of Li deposition in Li-ion batteries.•The universality of critical potential and concentration criteria for Li deposition in Li-ion batteries is discussed.•The morphology control is key to suppress the initiation and propagation of Li dendrites in Li metal batteries.•Uniform, elastic and resistive SEI layers may induce favorable morphology for Li deposition.
•The construction strategies of BC-based functional nanomateirals were summarized.•The biosynthetic and chemical modification of BC can expand its application fields.•Different components can be ...incorporated in situ or ex situ for functionalizing BC.•We focus on the preparation method, mechanism and performance of functional BC.•The sensor, photocatalytic, magnetic and optoelectronic applications were reviewed.
Bacterial cellulose (BC) is a fascinating and renewable natural nanomaterial characterized by favorable properties such as remarkable mechanical properties, porosity, water absorbency, moldability, biodegradability and excellent biological affinity. Intensive research and exploration in the past few decades on BC nanomaterials mainly focused on their biosynthetic process to achieve the low-cost preparation and application in medical, food, advanced acoustic diaphragms, and other fields. These investigations have led to the emergence of more diverse potential applications exploiting the functionality of BC nanomaterials. This review gives a summary of construction strategies including biosynthetic modification, chemical modification, and different in situ and ex situ patterns of functionalization for the preparation of advanced BC-based functional nanomaterials. The major studies being directed toward elaborate designs of highly functionalized material systems for many-faceted prospective applications. Simple biosynthetic or chemical modification on BC surface can improve its compatibility with different matrix and expand its utilization in nano-related applications. Moreover, based on the construction strategies of functional nanomaterial system, different guest substrates including small molecules, inorganic nanoparticles or nanowires, and polymers can be incorporated onto the surfaces of BC nanofibers to prepare various functional nanocomposites with outstanding properties, or significantly improved physicochemical, catalytic, optoelectronic, as well as magnetic properties. We focus on the preparation methods, formation mechanisms, and unique performances of the different BC derivatives or BC-based nanocomposites. The special applications of the advanced BC-based functional nanomaterials, such as sensors, photocatalytic nanomaterials, optoelectronic devices, and magnetically responsive membranes are also critically and comprehensively reviewed.
Gastrointestinal microbiota may be involved in
associated gastric cancer development. The aim of this study was to explore the possible microbial mechanisms in gastric carcinogenesis and potential ...dysbiosis arising from
infection.
Deep sequencing of the microbial 16S ribosomal RNA gene was used to investigate alterations in paired gastric biopsies and stool samples in 58 subjects with successful and 57 subjects with failed anti-
treatment, relative to 49
negative subjects.
In
positive subjects, richness and Shannon indexes increased significantly (both p<0.001) after successful eradication and showed no difference to those of negative subjects (p=0.493 for richness and p=0.420 for Shannon index). Differential taxa analysis identified 18 significantly altered gastric genera after eradication. The combination of these genera into a Microbial Dysbiosis Index revealed that the dysbiotic microbiota in
positive mucosa was associated with advanced gastric lesions (chronic atrophic gastritis and intestinal metaplasia/dysplasia) and could be reversed by eradication. Strong coexcluding interactions between
and
,
,
,
,
were found only in advanced gastric lesion patients, and were absent in normal/superficial gastritis group. Changes in faecal microbiota included increased
after successful
eradication and more upregulated drug-resistant functional orthologs after failed treatment.
infection contributes significantly to gastric microbial dysbiosis that may be involved in carcinogenesis. Successful
eradication potentially restores gastric microbiota to a similar status as found in uninfected individuals, and shows beneficial effects on gut microbiota.
A novel Sn4P3/graphite composite anode material with superior capacity and cycling performance (651 mA h g−1 after 100 cycles) is investigated by in situ X‐ray absorption spectroscopy. Extended X‐ray ...absorption fine structure modeling and detailed analysis of local environment changes are correlated to the cell capacity and reveal the mechanism of lithiation/delithiation process. Results show that in the first two lithiation/delithiation cycles crystalline Sn4P3 is fully converted to an amorphous SnPx phase, which in further cycles participates in reversible conversion and alloying reactions. The superior reversibility of this material is attributed to the highly dispersed SnPx in the graphite matrix, which provides enhanced electrical conductivity and prevents aggregation of Sn clusters during the lithiation/delithiation process. The gradual capacity fading in long‐term cycling is attributed to the observed increase in the size and the amount of metallic Sn clusters in the delithiated state, correlated to the reduced recovery of the SnPx phase. This paper reveals the mechanism responsible for the highly reversible tin phosphides and provides insights for improving the capacity and cycle life of conversion and alloying materials.
A novel Sn4P3/graphite composite anode for Li‐ion batteries with high reversible capacity and cycle life is investigated with in situ X‐ray absorption spectroscopy. The mechanism for reversible conversion and alloying reactions due to the amorphous SnPx phase and graphite matrix is proposed based on extended X‐ray absorption fine structure (EXAFS) modeling results.
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