Synergistic chemical and electrochemical strategy for high-performance Zn//MnO_(2) batteries

Aqueous rechargeable Zn//MnO_(2)batteries have been considered as the promising candidate for future energy storage system due to their economic and environmental merits.However,the high-performance Zn//MnO_(2)batteries are plagued by poor sluggish reaction kinetics and capacity degradation due to the strong electrostatic interactions and complicated reaction process.Herein,the synergistic effect of atom defects engineering and phase transformation mechanism is confirmed as the effective strategy to enhance ion/charge transfer kinetics and structural stability.Defects gradient controlling and electrochemically induced phase transformation from spinel to layered structure render the aqueous Zn//λ-MnO_(2)system delivers a high discharge capacity of 285 m Ah/g and capacity retention of 81%after 500 cycles.

Low-temperature and flexible strategy to in-situ fabricate ZrSiO_(4)-based ceramic composites via doping and tuning solid-state reaction

Synthetic zircon(ZrSiO_(4))ceramics are typically fabricated at elevated temperatures(over 1500℃),which would lead to high manufacturing cost.Meanwhile,reports about preparing ZrSiO_(4)-based ceramic composites via controlling the solid-state reaction between zirconia(ZrO_(2))and silica(SiO_(2))are limited.In this work,we proposed a low-temperature strategy to flexibly design and fabricate ZrSiO_(4)-based ceramic composites via doping and tuning the solid-state reaction.Two ceramic composites and ZrSiO_(4) ceramics were in-situ prepared by reactive fast hot pressing(FHP)at approximately 1250℃ based on the proposed strategy,i.e.,a ZrSiO_(4)-SiO_(2) dual-phase composite with bicontinuous interpenetrating and hierarchical microstructures,a ZrSiO_(4)-ZrO_(2) dual-phase composite with a microstructure of ZrO_(2) submicron-and nano-particles embedded in a micron ZrSiO_(4) matrix,and ZrSiO_(4) ceramics with a small amount of residual ZrO_(2) nanoparticles.The results showed that the phase compositions,microstructure configurations,mechanical properties,and wear resistance of the materials can be flexibly regulated by the proposed strategy.Hence,ZrSiO_(4)-based ceramic composites with different properties can be easily fabricated based on different application scenarios.These findings would offer useful guidance for researchers to flexibly fabricate ZrSiO_(4)-based ceramic composites at low temperatures and tailor their microstructures and properties through doping and tuning the solid-state reaction.

New dammarane-type saponins from the leaves of Panax notoginseng

Two new triterpenoid saponins named notoginsenoside-Ng3(1) and notoginsenoside-Ng4(2) along with three known saponins (3-5), were isolated from a water extract of the leaves of Panax notoginseng. Their structures were elucidated by HRESIMS, NMR, X-ray techniques and acid hydrolysis. Moreover,compound 2 was characterized with the conjugated double bonds side-chain, which was rarely found in this plant. The absolute configuration of notoginsenoside Fa (3) with five sugars was confirmed by the single-crystal X-ray diffraction for the first time. Acetylcholinesterase inhibitory activity experiments were also conducted, all the isolated saponins showed weak inhibitory activities in the final concentration of 0.16 mmol/L.

Psiguamers A-C, three cytotoxic meroterpenoids bearing a methylated benzoylphloroglucinol framework from Psidium guajava and total synthesis of 1 and 2

Three sesquiterpene-based meroterpenoids psiguamers A-C(1-3)with new skeletons were isolated from Psidium guajava leaves.Compounds(±)-1 and(±)-2 were two pairs of humulene-de「ived meroterpenoids bearing a rare methylated benzoylphloroglucinol unit,while 3 was an unprecedented adduct of bicyclogermacrene and methylated benzoylphloroglucinol.Their structures were determined based on comprehensive analyses of spectroscopic data,calculated electronic circular dichroism(ECD)spectra,total synthesis,and X-ray crystallographic data.The biomimetic synthesis of(±)-1 and(±)-2 was achieved.Compound(+)-1 exhibited cytotoxic activities against five human tumor cell lines(HCT-116,HepG2,BGC-823,A549,and U251),with IC_(50) values of 2.94,9.01,6.45,5.42,and 5.33 μmol/L,respectively.

Characteristic Dihydroagarofuran Sesquiterpenoids with Neuroprotective Effects from the Celastraceae Plant Tripterygium wilfordii

Ten new characteristic dihydroagarofuran sesquiterpenoids and three known ones were acquired from the Celastraceae plant Tripterygium wilfordii.Their structure characterizations were done through spectroscopic data,while compounds 10-12 were further con firmed by single crystal diffractions.Several dihydroagarofurans protected PC12 cells against H2O2-i nduced cytotoxicity as detected by CCK8 assay.Compounds 5-7 and 13 sign ificantly in creased the levels of reactive oxyge n species(ROS)and superoxide dismutase(SOD),and decreased malondialdehyde(MDA)levels.In addition,compounds 5-7 and 13 activated the Nrf2 signaling pathway and increased Nrf2,NQO1,and HO1 expression levels in PC12 cells after H_(2)O_(2) treatment.

Three new decarbonyl prenylphloroglucinols bearing unusual spirost subunits from Hypericum scabrum and their neuronal activities

Three novel polycyclic polyprenyled acylphloroglucinols,Hyperscabins A-C,were obtained from the aerial parts of Hypericum scabrum.They featured an unprecedented 5,5-spiro ketal subunit with the loss of C-2’carbonyl in the phloroglucinol ring.Their structures were characterized by extensive spectroscopic analyses,NMR calculations with DP4+analysis,calculated electronic circular dichroism(ECD)spectra and the application of modified Mosher’s methods.In the assay of[^(3)H]-5-HT and[^(3)H]-NE reuptake inhibition,compounds 1 and 2 showed good inhibito ry activity(81.8%and 83.2%)in 10μmol/L.In addition,compound 1 significantly increased cell viability in the experiment of oxygen and glucose deprivation/deoxygenation.

Local pixel patterns

In this paper, a new class of image texture operators is proposed. We firstly determine that the number of gray levels in each B × B subblock is a fundamental property of the local image texture. Thus, an occurrence histogram for each B × B sub-block can be utilized to describe the texture of the image. Moreover, using a new multi-bit plane strategy, i.e., representing the image texture with the occurrence histogram of the first one or more significant bit-planes of the input image, more powerful operators for describing the image texture can be obtained. The proposed approach is invariant to gray scale variations since the operators are, by definition,invariant under any monotonic transformation of the gray scale, and robust to rotation. They can also be used as supplementary operators to local binary patterns(LBP) to improve their capability to resist illuminance variation, surface transformations, etc.