Modelling phytoplankton-virus interactions: phytoplankton blooms and lytic virus transmission.

A dynamic reaction-diffusion model of four variables is proposed to describe the spread of lytic viruses among phytoplankton in a poorly mixed aquatic environment. The basic ecological reproductive index for phytoplankton invasion and the basic reproduction number for virus transmission are derived to characterize the phytoplankton growth and virus transmission dynamics. The theoretical and numerical results from the model show that the spread of lytic viruses effectively controls phytoplankton blooms. This validates the observations and experimental results of Emiliana huxleyi-lytic virus interactions. The studies also indicate that the lytic virus transmission cannot occur in a low-light or oligotrophic aquatic environment.

Implanting Transition Metal into Li2 O-Based Cathode Prelithiation Agent for High-Energy-Density and Long-Life Li-Ion Batteries.

Compensating the irreversible loss of limited active lithium (Li) is essentially important for improving the energy-density and cycle-life of practical Li-ion battery full-cell, especially after employing high-capacity but low initial coulombic efficiency anode candidates. Introducing prelithiation agent can provide additional Li source for such compensation. Herein, we precisely implant trace Co (extracted from transition metal oxide) into the Li site of Li2 O, obtaining (Li0.66 Co0.11 □0.23 )2 O (CLO) cathode prelithiation agent. The synergistic formation of Li vacancies and Co-derived catalysis efficiently enhance the inherent conductivity and weaken the Li-O interaction of Li2 O, which facilitates its anionic oxidation to peroxo/superoxo species and gaseous O2 , achieving 1642.7 mAh/g~Li2O prelithiation capacity (≈980 mAh/g for prelithiation agent). Coupled 6.5 wt % CLO-based prelithiation agent with LiCoO2 cathode, substantial additional Li source stored within CLO is efficiently released to compensate the Li consumption on the SiO/C anode, achieving 270 Wh/kg pouch-type full-cell with 92 % capacity retention after 1000 cycles.

One-Step Surface-to-Bulk Modification of High-Voltage and Long-Life LiCoO2 Cathode with Concentration Gradient Architecture.

Raising the charging cut-off voltage of layered oxide cathodes can improve their energy density. However, it inevitably introduces instabilities regarding both bulk structure and surface/interface. Herein, exploiting the unique characteristics of high-valence Nb5+ element, a synchronous surface-to-bulk-modified LiCoO2 featuring Li3 NbO4 surface coating layer, Nb-doped bulk, and the desired concentration gradient architecture through one-step calcination is achieved. Such a multifunctional structure facilitates the construction of high-quality cathode/electrolyte interface, enhances Li+ diffusion, and restrains lattice-O loss, Co migration, and associated layer-to-spinel phase distortion. Therefore, a stable operation of Nb-modified LiCoO2 half-cell is achieved at 4.6 V (90.9% capacity retention after 200 cycles). Long-life 250 Wh kg-1 and 4.7 V-class 550 Wh kg-1 pouch cells assembled with graphite and thin Li anodes are harvested (both beyond 87% after 1600 and 200 cycles). This multifunctional one-step modification strategy establishes a technological paradigm to pave the way for high-energy density and long-life lithium-ion cathode materials.

Lattice Engineering on Li2CO3-Based Sacrificial Cathode Prelithiation Agent for Improving the Energy Density of Li-Ion Battery Full-Cell.

Developing sacrificial cathode prelithiation technology to compensate for active lithium loss is vital for improving the energy density of lithium-ion battery full-cells. Li2CO3 owns high theoretical specific capacity, superior air stability, but poor conductivity as an insulator, acting as a promising but challenging prelithiation agent candidate. Herein, extracting a trace amount of Co from LiCoO2 (LCO), a lattice engineering is developed through substituting Li sites with Co and inducing Li defects to obtain a composite structure consisting of (Li0.906Co0.043▫0.051)2CO2.934 and ball milled LiCoO2 (Co-Li2CO3@LCO). Notably, both the bandgap and Li─O bond strength have essentially declined in this structure. Benefiting from the synergistic effect of Li defects and bulk phase catalytic regulation of Co, the potential of Li2CO3 deep decomposition significantly decreases from typical >4.7 to ≈4.25 V versus Li/Li+, presenting >600 mAh g-1 compensation capacity. Impressively, coupling 5 wt% Co-Li2CO3@LCO within NCM-811 cathode, 235 Wh kg-1 pouch-type full-cell is achieved, performing 88% capacity retention after 1000 cycles.

From Li to Na: Exploratory Analysis of Fe-Based Phosphates Polyanion-Type Cathode Materials by Mn Substitution.

Both LiFePO4 (LFP) and NaFePO4 (NFP) are phosphate polyanion-type cathode materials, which have received much attention due to their low cost and high theoretical capacity. Substitution of manganese (Mn) elements for LFP/NFP materials can improve the electrochemical properties, but the connection between local structural changes and electrochemical behaviors after Mn substitution is still not clear. This study not only achieves improvements in energy density of LFP and cyclic stability of NFP through Mn substitution, but also provides an in-depth analysis of the structural evolutions induced by the substitution. Among them, the substitution of Mn enables LiFe0.5 Mn0.5 PO4 to achieve a high energy density of 535.3 Wh kg-1 , while NaFe0.7 Mn0.3 PO4 exhibits outstanding cyclability with 89.6% capacity retention after 250 cycles. Specifically, Mn substitution broadens the ion-transport channels, improving the ion diffusion coefficient. Moreover, LiFe0.5 Mn0.5 PO4 maintains a more stable single-phase transition during the charge/discharge process. The transition of NaFe0.7 Mn0.3 PO4 to the amorphous phase is avoided, which can maintain structural stability and achieve better electrochemical performance. With systematic analysis, this research provides valuable guidance for the subsequent design of high-performance polyanion-type cathodes.

Full-Dimensional Analysis of Electrolyte Decomposition on Cathode-Electrolyte Interface: Establishing Characterization Paradigm on LiNi0.6Co0.2Mn0.2O2 Cathode with Potential Dependence.

Cathode electrolyte interphase (CEI) layers derived from electrolyte oxidative decomposition can passivate the cathode surface and prevent its direct contact with electrolyte. The inorganics-dominated inner solid electrolyte layer (SEL) and organics-rich outer quasi-solid-electrolyte layer (qSEL) constitute the CEI layer, and both merge at the junction without a clear boundary, which assures the CEI layer with both ionic-conducting and electron-blocking properties. However, the typical "wash-then-test" pattern of characterizations aiming at the microstructure of CEI layers would dissolve the qSEL and even destroy the SEL, leading to an overanalysis of electrolyte decomposition pathway and misassignment of CEI architecture (e.g., component and morphology). In this study, we established a full-dimensional characterization paradigm (combining Fourier transform infrared, solution NMR, X-ray photoelectron spectroscopy, and mass spectrometry technologies) and reconstructed the original CEI layer model. Besides, the feasibility of this characterization paradigm has been verified in a wide operating voltage range on a typical LiNixMnyCozO2 cathode.

Role of Substitution Elements in Enhancing the Structural Stability of Li-Rich Layered Cathodes.

Element doping/substitution has been recognized as an effective strategy to enhance the structural stability of layered cathodes. However, abundant substitution studies not only lack a clear identification of the substitution sites in the material lattice, but the rigid interpretation of the transition metal (TM)-O covalent theory is also not sufficiently convincing, resulting in the doping/substitution proposals being dragged into design blindness. In this work, taking Li1.2Ni0.2Mn0.6O2 as a prototype, the intense correlation between the "disordered degree" (Li/Ni mixing) and interface-structure stability (e.g., TM-O environment, slab/lattice, and Li+ reversibility) is revealed. Specifically, the degree of disorder induced by the Mg/Ti substitution extends in the opposite direction, conducive to sharp differences in the stability of TM-O, Li+ diffusion, and anion redox reversibility, delivering fairly distinct electrochemical performance. Based on the established paradigm of systematic characterization/analysis, the "degree of disorder" has been shown to be a powerful indicator of material modification by element substitution/doping.

Asymmetrical resource competition in aquatic producers: Constant cell quota versus variable cell quota.

In a shallow aquatic environment, a mathematical model with variable cell quota is proposed to characterize asymmetric resource competition for light and nutrients among aquatic producers. We investigate the dynamics of asymmetric competition models with constant and variable cell quotas and obtain the basic ecological reproductive indexes for aquatic producer invasions. The similarities and differences between the two types of cell quotas for dynamical properties and influences on asymmetric resource competition are explored through theoretical and numerical analysis. These results contribute to further revealing the role of constant and variable cell quotas in aquatic ecosystems.

Prolonged lifespan of initial-anode-free lithium-metal battery by pre-lithiation in Li-rich Li2Ni0.5Mn1.5O4 spinel cathode.

Anode-free lithium metal batteries (AF-LMBs) can deliver the maximum energy density. However, achieving AF-LMBs with a long lifespan remains challenging because of the poor reversibility of Li+ plating/stripping on the anode. Here, coupled with a fluorine-containing electrolyte, we introduce a cathode pre-lithiation strategy to extend the lifespan of AF-LMBs. The AF-LMB is constructed with Li-rich Li2Ni0.5Mn1.5O4 cathodes as a Li-ion extender; the Li2Ni0.5Mn1.5O4 can deliver a large amount of Li+ in the initial charging process to offset the continuous Li+ consumption, which benefits the cycling performance without sacrificing energy density. Moreover, the cathode pre-lithiation design has been practically and precisely regulated using engineering methods (Li-metal contact and pre-lithiation Li-biphenyl immersion). Benefiting from the highly reversible Li metal on the Cu anode and Li2Ni0.5Mn1.5O4 cathode, the further fabricated anode-free pouch cells achieve 350 W h kg-1 energy density and 97% capacity retention after 50 cycles.

Dynamics of Stoichiometric Autotroph-Mixotroph-Bacteria Interactions in the Epilimnion.

Autotrophs, mixotrophs and bacteria exhibit complex interrelationships containing multiple ecological mechanisms. A mathematical model based on ecological stoichiometry is proposed to describe the interactions among them. Some dynamic analysis and numerical simulations of this model are presented. The roles of autotrophs and mixotrophs in controlling bacterioplankton are explored to examine the experiments and hypotheses of Medina-Sánchez, Villar-Argaiz and Carrillo for La Caldera Lake. Our results show that the dual control (bottom-up control and top-down control) of bacteria by mixotrophs is a key reason for the ratio of bacterial and phytoplankton biomass in La Caldera Lake to deviate from the general tendency. The numerical bifurcation diagrams suggest that the competition between phytoplankton and bacteria for nutrients can also be an important factor for the decrease of the bacterial biomass in an oligotrophic lake.

Initiation of Acupoint Molecular Mechanisms for Manual Acupuncture Analgesia-Nuclear Factor κB Signaling Pathway.

OBJECTIVE: To identify the prominent molecular signaling in acupoints and explore their roles in initiating the analgesia effect of manual acupuncture (MA). METHOD: A three-step study was conducted, the experiment 1 was a genome-wide analysis of the tissue at acupoint Zusanli (ST 36), including 12 Wistar rats which were divided into control, control+MA1, and control+MA7 groups. In the experiment 2, the paw withdrawal latency (PWL), immunohistochemistry and Western blot analysis of phospho-nuclear factor kappa B (NFκB) p65 (p-p65), phospho-NFκB p50 (p-p50) at ST 36 were performed on rats of saline, saline+MA, and complete Freund's adjuvant (CFA)+MA groups (n=6). In experiment 3, 24 rats were divided into saline+DMSO, CFA+DMSO, CFA+DMSO+MA, and CFA+BAY 11-7082+MA groups, the PWL and immunofluorescence assay of NFκB p65 at ST 36 was conducted. RESULT: (1) The gene: inhibitor of NFκB (Nfkbia), interleukin-1ß (Il1b), interleukin-6 (Il6), chemokine c-x-c motif ligand 1 (Cxcl1), monocyte chemoattractant protein-1 (MCP-1/Ccl2) expressions in the control+MA7 group were significantly increased (P<0.05 or P<0.01), and the expression of NFκB p65 (Rela), NFκB p50 (Nfkb1) were increased in the control+MA7 group (P<0.05). (2) CFA+MA groups showed increased PWL from day 1 to 7 (P<0.01 vs. CFA), and the Western blot results were consistent with immunohistochemistry, the expression of NFκB p-p65 and NFκB p-p50 were significantly increased in the MA-related groups compared with control and CFA groups (P<0.05). (3) Compared with the CFA+DMSO+MA group, the PWL of the CFA+ BAY 11-7082+MA group decreased significantly and continued until day 5 and 7 (P<0.05 and P<0.01, respectively), and the NFκB p65 expression of CFA+BAY 11-7082+MA was significantly reduced compared with CFA+DMSO+MA (P<0.01). CONCLUSION: Local NFκB signaling cascade in acupoint caused by MA is an important step in initiating the analgesic effect, which would provide new evidence for the initiation of MA-effect and improve the understanding of the scientific basis of acupuncture analgesia.

Applying Complex Network and Cell-Cell Communication Network Diagram Methods to Explore the Key Cytokines and Immune Cells in Local Acupoint Involved in Acupuncture Treating Inflammatory Pain.

Manual acupuncture (MA) can effectively treat a variety of diseases, but its specific mechanism remains unclear. The "acupoint network" activated by MA participates in MA signal transduction, in which immune-related cells and cytokines play an important role. However, which cells and cytokines in the acupoint have changed after MA? What is the network relationship between them? Which cells and cytokines may play the most important role in MA effect? These problems are unclear. In this study, on the basis of affirming the analgesic, detumescence, and anti-inflammatory effect of MA, the concentration of 24 cytokines in ST36 acupoint in rats with inflammatory pain after MA treatment was detected by multiplex immunoassay technology. Then, using statistical and complex network and cell-cell communication (CCC) network diagram method to analyze the detected data depicts the network relationship between the cytokines and related cells objectively and establishes cytokine connection network and CCC network, respectively. The results showed that MA reinforced communication intensity between cells while reducing the overall correlation intensity. On this basis, the key cytokines and key cells at three MA time-points were screened out, cytokines IL-6, MCP-1, fibroblasts cell, and monocyte macrophage screened by the three methods at three MA time-points might be the key cytokines or key cells. After that, we detected the macrophages in ST36 acupoint by flow cytometry and immunofluorescence and found that the relative amount of macrophages increased significantly after MA, especially the macrophage of the dermis of skin. This study provided a basis for revealing the initiated mechanism of MA effect.

A Bioinspired Functionalization of Polypropylene Separator for Lithium-Sulfur Battery.

Lithium-sulfur batteries have received intensive attention, due to their high specific capacity, but the shuttle effect of soluble polysulfide results in a decrease in capacity. In response to this issue, we develop a novel tannic acid and Au nanoparticle functionalized separator. The tannic acid and gold nanoparticles were modified onto commercial polypropylene separator through a two-step solution process. Due to a large number of phenolic hydroxyl groups contained in the modified layer and the strong polarity of the gold nanoparticles, the soluble polysulfide generated during battery cycling is well stabilized on the cathode side, slowing down the capacity fade brought by the shuttle effect. In addition, the modification effectively improves the electrolyte affinity of the separator. As a result of these benefits, the novel separator exhibits improved battery performance compared to the pristine polypropylene separator.

Acupuncture Alleviates Rheumatoid Arthritis by Immune-Network Modulation.

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune inflammatory and debilitating disease that involves the systemic imbalance of the immune network. Previous studies have shown that acupuncture can help treat RA. However, its specific mechanisms are not fully understood. Thus, the present study was designed to clarify the mechanisms of acupuncture acted on RA via immune network modulation using complete Freund's adjuvant (CFA)-induced arthritic rats. Results revealed that manual acupuncture (MA) could alleviate the inflammation and pain of infected joints. Moreover, MA could effectively stimulate the innate immune cytokines (IL-1[Formula: see text], IL-1[Formula: see text], IL-6, IL-7, IL-18, TNF-[Formula: see text]) and adaptive immunity cytokines (IL-2, IL-12, IFN-[Formula: see text], IL-4, IL-5, IL-10, IL-13, IL-17) as the main part of the immune response and repaired damage of RA. These complex immunomodulatory processes were analyzed quantitatively by cell-cell communication (CCC) networks. The CCC networks demonstrated that the immune networks were enhanced with the development of RA, while MA enhanced the immune networks in the early stage to act on RA and promoted the immune-network to a normal level at the late stage. Moreover, we found that monocyte/macrophage and endothelial cells were the key cells of innate immunity and body cells; TH1, TH2 and B cells were the key cells of adaptive immunity, which were also the main target cells for MA regulation.

Applying Statistical and Complex Network Methods to Explore the Key Signaling Molecules of Acupuncture Regulating Neuroendocrine-Immune Network.

The mechanisms of acupuncture are still unclear. In order to reveal the regulatory effect of manual acupuncture (MA) on the neuroendocrine-immune (NEI) network and identify the key signaling molecules during MA modulating NEI network, we used a rat complete Freund's adjuvant (CFA) model to observe the analgesic and anti-inflammatory effect of MA, and, what is more, we used statistical and complex network methods to analyze the data about the expression of 55 common signaling molecules of NEI network in ST36 (Zusanli) acupoint, and serum and hind foot pad tissue. The results indicate that MA had significant analgesic, anti-inflammatory effects on CFA rats; the key signaling molecules may play a key role during MA regulating NEI network, but further research is needed.

Inactivation kinetics of ß-N-acetyl-D-glucosaminidase from green crab (Scylla serrata) by guanidinium chloride.

ß-N-acetyl-D-glucosaminidase (NAGase) is a major member in chitinolytic enzymes system, which plays an important role in the hatching and molting processes of marine organism. The effects of guanidinium chloride (GuHCl) on the activity of NAGase from green crab (Scylla serrata) were investigated in this study. In results, GuHCl causes reversible inactivation of the enzyme at below 0.8 M concentrations, and the IC50 is estimated to be 0.15 M. The relationship between the enzyme activity and conformation was charaterized by monitoring the change of protein fluorescence spectra. With increasing GuHCl concentration, the fluorescence intensity of the enzyme distinctly decreases , and the maximal emission peaks appear red-shifted (from 338 nm to 343 nm). The enzyme inactivation precedes conformational changes, indicating that the enzyme active site is more flexible than the whole enzyme molecule. The result of the kinetics of inactivation shows that the value of k(+0) is larger than that of k(+0)'. It suggests that the substrate could protect the enzyme to a certain extent during guanidine denaturation. Our results provide important new insights in marine organism culture, especially in crustacean growth.

Inactivation kinetics of beta-N-acetyl-D-glucosaminidase from green crab (Scylla serrata) in dioxane solution.

Beta-N-acetyl-D-glucosaminidase (NAGase, EC.3.2.1.52), which catalyzes the cleavage of N-acetylglucosamine polymers, is a composition of chitinase and cooperates with endo-chitinase and exo-chitinase to disintegrate chitin into N-acetylglucosamine (NAG). In this investigation, A NAGase from green crab (Scylla serrata) was purified and the effects of dioxane on the enzyme activity for the hydrolysis of p-Nitrophenyl-N-acetyl-beta-D-glucosaminide (pNP-NAG) were studied. The results show that appropriate concentrations of dioxane can lead to reversible inactivation of the enzyme and the inactivation is classified as mixed type. The value of IC50, the dioxane (inactivator) concentration leading to 50% activity lost, is estimated to be 0.68%. The kinetics of inactivation of NAGase in the appropriate concentrations of dioxane solution has been studied using the kinetic method of the substrate reaction. The rate constants of inactivation have been determined. The results showed that k+0 is much larger than k'+0, indicating the free enzyme molecule is more fragile than the enzyme-substrate complex in the dioxane solution. It is suggested that the presence of the substrate offers marked protection of this enzyme against inactivation by dioxane.

Studies on the chemical modification of the essential groups of N-Acetyl-beta-D-glucosaminidase from viscera of green crab (Scylla Serrata).

The chemical modification of N-acetyl-beta-D: -glucosaminidase (EC3.2.1.30) from viscera of green crab (Scylla serrata) has been first studied. The modification of indole groups of tryptophan of the enzyme by N-bromosuccinimide can lead to complete inactivation, accompanying the absorption decreasing at 275 nm and the fluorescence intensity quenching at 338 nm, indicating that tryptophan is essential residue to the enzyme. The modification of histidine residue, the carboxyl groups, and lysine residue inactivates the enzyme completely or incompletely. The results show that imidazole groups of histidine residue or sulfhydryl residues, the carboxyl groups of acidic amino acid, amino groups of lysine residue, and indole groups of tryptophan were essential for the catalytic activity of enzyme, while the results demonstrate that the disulfide bonds and the carbamidine groups of arginine residues are not essential to the enzyme's function.

Inhibitory kinetics of phenol on the enzyme activity of beta-N-acetyl-D-glucosaminidase from green crab (Scylla serrata).

Chemical pollution such as chromium and phenol in the sea water has been increasing in recent years in China sea. At the same time, marine shellfish such as prawn and crab are sensitive to this pollution. beta-N-acetyl-D-glucosaminidase (NAGase, EC.3.2.1.52) catalyzes the cleavage the oligomers of N-acetylglucosamine (NAG) into the monomer. In this paper, the effects of phenol on the enzyme activity from green crab (Scylla serrata) for the hydrolysis of p-nitrophenyl-N-acetyl-beta-D-glucosaminide (pNP-NAG) have been studied. The results showed that appropriate concentrations of phenol could lead to reversible inhibition on the enzyme and the inhibitor concentration leading to 50% activity lost, IC(50), was estimated to be 75.0+/-2.0 mM. The inhibitory kinetics of phenol on the enzyme in the appropriate concentrations of phenol has been studied using the kinetic method of substrate reaction. The time course of the enzyme for the hydrolysis of pNP-NAG in the presence of different concentrations of phenol showed that at each phenol concentration, the rate decreased with increasing time until a straight line was approached. The results show that the inhibition of the enzyme by phenol is a slow, reversible reaction with fractional remaining activity. The microscopic rate constants are determined for the reaction on phenol with the enzyme.