Degradation of the Novel Heterocyclic Insecticide Pyraquinil in Water: Kinetics, Degradation Pathways, Transformation Products Identification, and Toxicity Assessment.

As new pesticides are continuously introduced into agricultural systems, it is essential to investigate their environmental behavior and toxicity effects to better evaluate their potential risks. In this study, the degradation kinetics, pathways, and aquatic toxicity of the new fused heterocyclic insecticide pyraquinil in water under different conditions were investigated for the first time. Pyraquinil was classified as an easily degradable pesticide in natural water, and hydrolyzes faster in alkaline conditions and at higher temperatures. The formation trends of the main transformation products (TPs) of pyraquinil were also quantified. Fifteen TPs were identified in water using ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Orbitrap-HRMS) and Compound Discoverer software, which adopted suspect and nontarget screening strategies. Among them, twelve TPs were reported for the first time and 11 TPs were confirmed by synthesis of their standards. The proposed degradation pathways have demonstrated that the 4,5-dihydropyrazolo[1,5-a]quinazoline skeleton of pyraquinil is stable enough to retain in its TPs. ECOSAR prediction and laboratory tests showed that pyraquinil was "very toxic" or "toxic" to aquatic organisms, while the toxicities of all of the TPs are substantially lower than that of pyraquinil except for TP484, which was predicted to pose a higher toxicity. The results are important for elucidating the fate and assessing the environmental risks of pyraquinil, and provide guidance for scientific and reasonable use.

Synthesis and characterization of an artificial glucosinolate bearing a chlorthalonil-based aglycon as a potent inhibitor of glucosinolate transporters.

Glucosinolates (GSLs) are specialized metabolites in plants of the order Brassicales. GSL transporters (GTRs) are essential for the redistribution of GSLs and also play a role in controlling the GSL content of seeds. However, specific inhibitors of these transporters have not been reported. In the current study, we described the design and synthesis of 2,3,4,6-tetrachloro-5-cyanophenyl GSL (TCPG), an artificial GSL bearing a chlorothalonil moiety as a potent inhibitor of GTRs, and evaluated its inhibitory effect on the substrate uptake mediated through GTR1 and GTR2. Molecular docking showed that the position of the ß-D-glucose group of TCPG was significantly different from that of the natural substrate in GTRs and the chlorothalonil moiety forms halogen bonds with GTRs. Functional assays and kinetic analysis of the transport activity revealed that TCPG could significantly inhibit the transport activity of GTR1 and GTR2 (IC50 values (mean ± SD) being 79 ± 16 µM and 192 ± 14 µM, respectively). Similarly, TCPG could inhibit the uptake and phloem transport of exogenous sinigrin by Arabidopsis thaliana (L.) Heynh leaf tissues, while not affecting that of esculin (a fluorescent surrogate for sucrose). TCPG could also reduce the content of endogenous GSLs in phloem exudates. Together, TCPG was discovered as an undescribed inhibitor of the uptake and phloem transport of GSLs, which brings novel insights into the ligand recognition of GTRs and provides a new strategy to control the GSL level. Further tests on the ecotoxicological and environmental safety of TCPG are needed before using it as an agricultural or horticultural chemical in the future.

Study on Characteristics and Lignification Mechanism of Postharvest Banana Fruit during Chilling Injury.

The banana is prone to chilling injury (CI) at low temperature and showing a series of chilling symptoms, such as peel browning, etc. Lignification is a response to abiotic stress and senescence, which is an important manifestation of fruits and vegetables during chilling exposure. However, little is known about the lignification of bananas during low-temperature storage. Our study explored the characteristics and lignification mechanism of banana fruits during low-temperature storage by analyzing the changes of chilling symptoms, oxidative stress, cell wall metabolism, microstructures, and gene expression related to lignification. The results showed that CI inhibited post-ripening by effecting the degradation of the cell wall and starch and accelerated senescence by increasing O2- and H2O2 content. For lignification, Phenylalanine ammonia-lyase (PAL) might start the phenylpropanoid pathway of lignin synthesis. Cinnamoyl-CoA reductase 4 (CCR4), cinnamyl alcohol dehydrogenase 2 (CAD2), and 4-coumarate--CoA ligase like 7 (4CL7) were up-regulated to promote the lignin monomer's synthesis. Peroxidase 1 (POD1) and Laccase 3 (LAC3) were up-regulated to promote the oxidative polymerization of lignin monomers. These results suggest that changes of the cell wall structure and cell wall metabolism, as well as lignification, are involved in the senescence and quality deterioration of the banana after chilling injury.

Hybrid bismuth oxide-graphine oxide nanomaterials improve the signal-to-noise response of small molecules analyzed by matrix assisted laser desorption ionization-time-of-flight mass spectrometry.

Matrix-assisted laser desorption ionization (MALDI) has received increasing attention for the analysis small molecules. Nanomaterials are frequently used as the matrix in LDI, and various inorganic materials have been developed, particularly those based on thermally-driven positive DI mechanisms. However, the unwanted detection of alkali metal ion adducts in the positive ion mode can compromise small molecule identification. Here, we report the synthesis and application of a novel hybrid bismuth oxide-graphene oxide (Bi2O3@GO) semiconductor matrix for the analysis of small molecules by LDI-time-of-flight mass spectrometry (TOF-MS) operating in the negative ion mode. The structure of the semiconductor nanomaterial was characterized using conventional methods and its performance for the detection of small molecules (e.g., amino acids, fatty acids, sugars and other small molecules) was compared with traditional DI matrices (e.g., cyano-4-hydroxycinnamic acid, 2,5-dihydroxybenzoic acid, 9-aminoacridine and GO). The results showed that the negative ion LDI-TOF MS of small molecules on Bi2O3@GO were free of matrix-related interferences, and possessed good signal intensity and repeatability. Application of Bi2O3@GO to the quantitative determination of glucose in human serum and soft drinks confirmed that the hybrid matrix could also be applied to complex samples. Conclusions drawn from the experimental results, computational chemistry calculations, and previous studies, suggesting that interfacial photogenerated thermal electron transfer and capture are key processes in the LDI mechanism.

Research and clinical translation of trilayer stent-graft of expanded polytetrafluoroethylene for interventional treatment of aortic dissection.

The aortic dissection (AD) is a life-threatening disease. The transcatheter endovascular aortic repair (EVAR) affords a minimally invasive technique to save the lives of these critical patients, and an appropriate stent-graft gets to be the key medical device during an EVAR procedure. Herein, we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease. The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene (ePTFE) membranes. Each of the inner and outer surfaces of the stent-graft was covered by an ePTFE membrane, and the two membranes were then sintered together. The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro. Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability. The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo. In nine canine experiments, the blood vessels of the animals implanted with the stent-grafts were of good patency, and there were no thrombus and obvious stenosis by angiography after implantation for 6 months. Furthermore, all of the nine clinical cases experienced successful implantation using the stent-graft and its postrelease delivery system, and the 1-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.

[Chiral separation of new chiral insecticide pyraquinil isomers and establishment of analytical methods in vegetables].

Pyraquinil (Pyr), with a new skeleton of pyrazolo[1,5-a]quinazoline fused heterocycle, is a new chiral insecticide independently developed by South China Agricultural University in 2017. In previous studies, we found that pyraquinil can effectively control the lepidopteran pest population on cruciferous crops. Remarkably, the insecticidal activity of pyraquinil was 64-fold better than that of fipronil against the fipronil-resistant Plutella xylostella field population. Pesticides with new active mechanisms should be developed in the future to cope with the development of resistance to Plutella xylostella. Therefore, pyraquinil with new active sites has the potential to be the main rotation variety for the control of Plutella xylostella. Thus, pyraquinil has a broad prospect for application in the future. However, a chiral separation and analysis method for pyraquinil and oxidation products using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has not been established yet. Based on the physical and chemical properties of the new chiral pesticide pyraquinil, we screened chiral chromatographic columns and optimized the mobile phase ratio in this study. The separation and analysis methods for pyraquinil were developed based on the QuEChERS (quick, easy, cheap, effective, rugged, safe) system. Simultaneously, we also established oxidation metabolites. These methods were used for the simultaneous determination of the chiral isomers of pyraquinil and oxidation products in pakchoi (Brassica rapa ssp. chinensis L.) and water spinach (Ipomoea aquatica Forsk) via HPLC-MS/MS. The Chiral INC column (250 mm×4.6 mm, 5 µm) was used for separation. Ammonium formate aqueous solution (2 mmol/L) and acetonitrile were used as the mobile phases. The column temperature was 28 ℃. The injection volume was 1 µL, and the flow rate was 0.5 mL/min. MS analysis was performed using an electrospray ionization source in the negative and multiple reaction monitoring modes. We found that under the optimized conditions, the resolution of the four isomers of pyraquinil were 1.63, 2.83, and 1.74, respectively, and the resolution of the isomers of the pyraquinil oxidation product was 5.82, which achieved baseline separation. Then, the absolute configuration and peak order of pyraquinil and oxidation product isomers were determined by derivatization. The order of the peaks was RS-Pyr, SS-Pyr, RR-Pyr, SR-Pyr, S-Pyr+O, and R-Pyr+O. The purification conditions of sample pretreatment were optimized; 1 g (0.835 g MgSO4+0.150 g PSA+0.015 g GCB) was determined to be the optimal purification agent; and the average recoveries ranged from 80% to 110%. The chiral isomers of pyraquinil and oxidation products showed good linearity in the concentration range of 1.25 to 1250 µg/L and 2.5 to 2500 µg/L respectively. The square of the regression coefficient of the linear equation (R2) was greater than 0.99. The matrix effects of the pyraquinil and oxidation product isomers in pakchoi ranged from 6.1 to 30.6. In the water spinach, the matrix effect of the pyraquinil and oxidation product isomers were in the range of 0.7-26.8. The average recoveries of pyraquinil isomer at three spiked levels of 0.25, 5, 100 µg/kg in samples (pakchoi and water spinach) ranged from 90.2% to 110.6%. The oxidation product isomer average recoveries in samples (pakchoi and water spinach) spiked with 0.5, 10, 200 µg/kg ranged from 72.6% to 100.1%. Further, the relative standard deviations (RSDs) were 0.5%-9.4%. In water spinach, the intra-day and inter-day repeatability RSDs ranged from 0.5% to 8.7% and 1.0%to 8.6%, respectively. In pakchoi, the intra-day and inter-day repeatability RSDs ranged from 0.6% to 9.4% and 1.0% to 7.6%, respectively. These results indicate that the proposed method has satisfactory sensitivity, accuracy, and precision. This study can provide analytic technology for a novel chiral pesticide for environmental behavior studies, quality control, and pharmacodynamics evaluation, as well as significant technical support for the development and application of new pesticides.

Study on Absorption, Distribution, Metabolism, and Excretion Properties of Novel Insecticidal GABA Receptor Antagonist, Pyraquinil, in Diamondback Moth Combining MALDI Mass Spectrometry Imaging and High-Resolution Mass Spectrometry.

A thorough understanding of absorption, distribution, metabolism, and excretion (ADME) of insecticide candidates is essential in insecticide development and structural optimization. Here, ADME of pyraquinil, a novel insecticidal GABA receptor antagonist, in Plutella xylostella larvae during the accumulation phase and depuration phase was investigated separately using a combination of UHPLC-Q-Orbitrap, HPLC-MS/MS, and MALDI-MSI. Five new metabolites of pyraquinil were identified, and a metabolic pathway was proposed. The oxidative metabolite (pyraquinil-sulfone) was identified as the main metabolite and confirmed by its standard. Quantitative results showed that pyraquinil was taken up by the larvae rapidly and then undergone a cytochrome P450s-mediated oxidative transformation into pyraquinil-sulfone. Both fecal excretion and oxidative metabolism were demonstrated to be predominant ways to eliminate pyraquinil in P. xylostella larvae during accumulation, while oxidative metabolism followed by fecal excretion was probably the major pathway during depuration. MALDI-MSI revealed that pyraquinil was homogeneously distributed in the larvae, while pyraquinil-sulfone presented a continuous enrichment in the midgut during accumulation. Conversely, pyraquinil-sulfone located in hemolymph can be preferentially eliminated during depuration, suggesting its tissue tropism. It improves the understanding of the fate of pyraquinil in P. xylostella and provides useful information for insecticidal mechanism elucidation and structural optimization of pyraquinil.

Design of new glycosyl-O-fipronil conjugates with improved hydrolysis efficiency assisted by molecular simulations.

BACKGROUND: In a previous study, we showed that two glycosyl-pesticide conjugates with a ß-d-glucoside moiety, N-{3-cyano-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl)-sulfinyl]-1H-pyrazol-5-yl}-2-aminoethyl-ß-d-glucopyranoside (GOF) and N-{3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl) sulfinyl]-1H-pyrazol-5-yl}-1-(2-triazolethyl-ß-d-glucopyranoside)-1H-1,2,3-triazole-4-methanamine (GOTF), can move in the phloem and be hydrolyzed by ß-glucosidase at different rates. Simulations were carried out to investigate differences in the hydrolysis process in GOF, GOTF and p-nitrophenyl ß-d-glucopyranoside (pNPG). A new series of glycosyl-O-fipronil conjugates was then designed and synthesized based on the simulation results. The phloem mobilities of the new conjugates were examined using a Ricinus model, and their hydrolysis efficiencies based on ß-glucosidase were determined. RESULTS: New glycosyl-O-fipronil conjugates GOE2-6 were designed and synthesized. To reduce steric hindrance, the conjugating site of the glycone moiety was moved to the 4'-sulfonyl group on the pyrrole ring. As a result, the hydrolysis efficiencies of the new conjugates were significantly improved, with GOE4 having the highest hydrolysis efficiency. All five conjugates could be transported in Ricinus phloem sap, consistent with previously studied glycosyl-O-fipronil conjugates. The insecticidal activities of the conjugates were tested against Plutella xylostella. CONCLUSION: A strategy for the development of new phloem-mobile pesticides was proposed: linking a glycosyl group to the existing pesticide structure with a linear alkyl connection approximately four carbons in length. The resultant conjugates feature not only good phloem mobility, but also potential high bioactivity due to the efficient release of active pesticide components under the action of glucosidase. © 2022 Society of Chemical Industry.

Design, synthesis, and insecticidal activities of novel 5-substituted 4,5-dihydropyrazolo[1,5-a]quinazoline derivatives.

BACKGROUND: Chemical pesticides are the main measures for pest control, but have caused growing resistance of pests and brought a series of environmental problems. Development of high-efficient insecticidal molecules with novel scaffolds is therefore particularly urgent. RESULTS: Based on a [5 + 1] annulation reaction with 5-amino-1H-phenylpyrazole and dialkyl bromomalonate, 27 novel five-substituted 4,5-dihydropyrazolo[1,5-a]quinazolines were designed following the intermediate derivatization method and synthesized. Bioassay results indicated that most of the test compounds displayed good insecticidal activities against Plutella xylostella, Spodoptera frugiperda, and Solenopsis invicta. In particular, the insecticidal activities of compounds 4a, 4f, and 4m against P. xylostella [median lethal concentration (LC50 ) values ranged from 3.87 to 5.10 mg L-1 ] were comparable to that of indoxacarb (LC50 = 4.82 mg L-1 ). In addition, compounds 4a and 9e showed similar high insecticidal activities against Spodoptera frugiperda (mortality rate = 79.63% and 72.12%) at 100 mg L-1 , comparable to that of fipronil (mortality rate: 68.44%); compound 9a showed possible delayed toxicity against Solenopsis invicta (mortality rate: 95.66%) after 5 days of treatment at 1.0 mg L-1 . CONCLUSION: Due to their high insecticidal activities against P. xylostella, compound 4m, 4a, and 4f could be considered as qualified candidates for novel insecticide. Several other 4,5-dihydropyrazolo[1,5-a]quinazolines with relatively high bioactivity, such as compounds 9a and 9e, are also worth further optimization as potential insecticide or anticide candidates.

Design, Synthesis, and Insecticidal Activity of 5,5-Disubstituted 4,5-Dihydropyrazolo[1,5-a]quinazolines as Novel Antagonists of GABA Receptors.

To control the development of resistance to conventional insecticides acting as γ-aminobutyric acid (GABA) receptor antagonists (e.g., fipronil), new GABAergic 5,5-disubstituted 4,5-dihydropyrazolo[1,5-a]quinazolines were designed via a scaffold-hopping strategy and synthesized with a facile method. Among the 50 target compounds obtained, compounds 5a, 5b, 7a, and 7g showed excellent insecticidal activities against a susceptible strain of Plutella xylostella (LC50 values ranging from 1.03 to 1.44 µg/mL), which were superior to that of fipronil (LC50 = 3.02 µg/mL). Remarkably, the insecticidal activity of compound 5a was 64-fold better than that of fipronil against the field population of fipronil-resistant P. xylostella. Electrophysiological studies against the housefly GABA receptor heterologously expressed in Xenopus oocytes indicated that compound 5a could act as a potent GABA receptor antagonist, and IC50 was calculated to be 32.5 nM. Molecular docking showed that the binding poses of compound 5a with the housefly GABA receptor can be different compared to fipronil, which explains the effectiveness of compound 5a against fipronil-resistant insects. These findings have suggested compound 5a as a lead compound for a novel GABA receptor antagonist controlling field-resistant insects and provided a basis for further design, structural modification, and development of 4,5-dihydropyrazolo[1,5-a]quinazoline motifs as new insecticidal GABA receptor antagonists.

Design of dental implants at materials level: An overview.

Due to the excellent restoration of masticatory function, satisfaction on aesthetics and other superiorities, dental implants represent an effective method to resolve tooth losing and damaging. Current dental implant systems still have problems waiting to be addressed, and problems are centralized on the materials of implant bodies. This review aims to summarize major developments in the field of dental implant materials, starting with an overview on structures, procedures of dental implants and challenges of implant materials. Next, implant materials are examined in three categories, that is, metals, ceramics, and polymers, their mechanical properties, biocompatibility, and bioactivity are summarized. And as an important aspect, strategies of surface modification are also reviewed, along with some finite element analysis to guiding the research direction of implant materials. Finally, the conclusive remarks are outlined to provide an outlook on the future research directions and prospects of dental implants.

Both Phosphonic Acid- and Fluorine-Containing Poly(aryl ether)-hydroxyapatite Biocomposites: Toward Enhanced Biocompatibility and Bonelike Elastic Modulus.

Metal-based implants possess excellent mechanical strength, corrosion resistance, and biocompatibility and can deliver favorable performances in clinic treatments. However, modulus mismatching is considered a common defect for metal-based materials, while polymer-based materials with a bonelike elastic modulus have been regarded as one of the most promising candidates for bone replacement implants. In this work, a phosphonic acid- and fluorine-containing poly(aryl ether) (PAE) resin is designed and synthesized, which is determined to be an amorphous polymer with excellent thermostability. The elastic modulus of composites is improved to 15.7 GPa by reinforcing with 60 wt % hydroxyapatite (HA), which demonstrates admirable protein adsorption and hydrophilicity. After 14 days of immersion in simulated body fluid, a layer of HA deposition can be observed, indicating favorable bioactivity in advance, and the preliminary in vitro cell experiments also suggest that PAE-HA composites possess favorable cell responses on adhesion, proliferation, and differentiation, which reveal the feasibility of synthesized polymers to be employed as bone replacement materials, while the adjustability in molecular chains also leaves room for further investigations.

The linker length of glucose-fipronil conjugates has a major effect on the rate of bioactivation by ß-glucosidase.

BACKGROUND: Endogenous plant ß-glucosidases can be utilized to hydrolyze pro-pesticides and release the bioactive pesticide. Two related glucose-fipronil conjugates with different linkers structure, N-{3-cyano-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl) sulfinyl]-1H-pyrazol-5-yl}-1-(2-triazolethyl-ß-d-glucopyranoside)-1H-1,2,3-triazole-4-methanamine (GOTF) and N-{3-cyano-1-[2,6-dichloro-4-(trifluoromethyl) phenyl]-4-[(trifluoromethyl)-sulfinyl]-1H-pyrazol-5-yl}-2-aminoethyl-ß-d-glucopyranoside (GOF), were deglucolysated by ß-glucosidase both in vitro and in vivo at different rates. Here, the basis for these differences was investigated by revealing the kinetics of the reaction and by modeling molecular docking between enzyme and substrate. RESULTS: Results from kinetic study showed that the reaction rate was the main reason for the poorer rate of GOF hydrolysis with respect to GOTF. Modeling of substrate docking indicated that the spacer arm of glucose-fipronil conjugates affects the strength of non-covalent bonds within the active site and the position of fipronil within the pocket. Four glucose-fipronil conjugates and four corresponding aglycones were synthesized, and the hydrolysis data confirmed that the increased tether length between the bulky aglycone and glycone would lead to faster hydrolysis rate. The bioassay results indicated that most glucose-fipronil conjugates displayed moderate to excellent insecticidal activities in vivo against Plutella xylostella larvae. CONCLUSION: This study provides a potential strategy to optimize the substrate structure to enhance hydrolytic specificity in order to design appropriate phloem mobile pro-pesticides. © 2018 Society of Chemical Industry.

Synthesis and antiphytoviral activity of α-aminophosphonates containing 3, 5-diphenyl-2-isoxazoline as potential papaya ringspot virus inhibitors.

α-Aminophosphonates compounds containing 3,5-diphenyl-2-isoxazoline were synthesized and evaluated for their bioactivity. Seventeen of them showed good bioactivity (protection effect > 50%) in vivo against papaya ringspot virus, while two of them (V29 and V45) exhibited excellent antiviral activity (both 77.8%). In the latter case, the antiviral activity was close to that of antiphytovirucides ningnanmycin and dufulin (both 83.3%) at 500 mg/L. The preliminary structure-activity relationships indicated that the bioactivity was strongly influenced by the substituents.

Design of a New Glutamine-Fipronil Conjugate with α-Amino Acid Function and Its Uptake by A. thaliana Lysine Histidine Transporter 1 ( AtLHT1).

Creating novel pesticides with phloem mobility is essential for controlling insects in vascular tissue and root, and conjugating existing pesticides with amino acid is an effective approach. In order to obtain a highly phloem-mobile candidate for efficient pesticides, an electro-neutral l-glutamine-fipronil conjugate (l-GlnF) retaining α-amino acid function was designed and synthesized to fit the substrate specificity of an amino acid transporter. Cotyledon uptake and phloem loading tests with Ricinus communis have verified that l-GlnF was phloem mobile, and its phloem mobility was higher than that of its enantiomer d-GlnF and other previously reported amino acid-fipronil conjugates. Inhibition experiments then suggested that the uptake of l-GlnF was, at least partially, mediated by an active transport mechanism. This inference was further strengthened by assimilation experiments with Xenopus oocytes and genetically modified Arabidopsis thaliana, which showed a direct correlation between the uptake of l-GlnF and the expression of amino acid transporter AtLHT1. Thus, conjugation with l-Gln appears to be a potential strategy to ensure the uptake of pesticides via an endogenous amino acid transport system.

In situ template synthesis of hierarchical porous carbon used for high performance lithium-sulfur batteries.

Hierarchical porous carbon (HPC) consists of micropores, mesopores and macrospores which are synthesized by in situ formation of template followed by acid etching. The obtained pores are three-dimensional and interconnected, and evenly distributed in the carbon matrix. By adjusting the ratio of the raw materials, the high specific surface area and large pore volume is afforded. The obtained HPC-3 samples possess graphite flakes and locally graphited-carbon walls, which provide good electrical conductivity. These unique characteristics make these materials suitable cathode scaffolds for Li-S batteries. After encapsulating 61% sulfur into HPC-3 host, the S/HPC-3 composite exhibits excellent cycling stability, high columbic efficiency, and superior rate cycling as a cathode material. The S/HPC-3 composite cathode displays an initial discharge capacity of 1059 mA h g-1, and a reversible capacity of 797 mA h g-1 after 200 cycles at 0.2C. The discharge capacities of the S/HPC-3 composite cathode after every 10 cycles at 0.1, 0.2, 0.5, 1, and 2C are 1119, 1056, 982, 921, and 829 mA h g-1, respectively.