3D porous Co2V2O7·3.3H2O microflowers electrode material is obtained via a facile co-precipitation technology. The electrochemical measurements demonstrate that the 3D porous Co2V2O7·3.3H2O ...microflowers electrode material has high capacitance (351 F g−1) and outstanding cycling performance, as well as good rate capability as electrochemical capacitors (ECs) electrode materials.
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•3D porous Co2V2O7·3.3H2O microflowers are prepared via a co-precipitation method.•An interesting structural evolution process of 3D microflowers was observed.•Superior capacitive performance was achieved by the Co2V2O7·3.3H2O.•The 3D microflowers show superior cycle stability.
Cobalt vanadates and their composites have drawn tremendous attention because of their outstanding cycling stability. Rational design of 3D micro/nano-structures using a facile strategy has a promising potential for supercapacitor applications. Herein, we propose a 3D porous Co2V2O7·3.3H2O microflowers electrode as a cathode for pseudocapacitor via a simple co-precipitation technology. The resultant Co2V2O7·3.3H2O with microflowers structure exhibits a high specific capacitance of 351 F g−1 at a current density of 1 A g−1, and an ultralong cycle lifetime with 103% capacitance retention after 30,000 cycles. An asymmetric supercapacitor device is also successfully assembled consisting of Co2V2O7·3.3H2O cathode and rGO anode. The optimized ACS device with a potential window of 0–1.5 V delivers a high energy density and an excellent cycle lifetime. These superior electrochemical properties will render the 3D porous Co2V2O7·3.3H2O microflowers material as an attractive material for promising application in energy storage systems.
On the basis of a novel ynol‐diene cyclization developed as a rapid access to tropone unit, the first divergent strategy to 17‐nor‐cephalotane diterpenoids has been successfully established. ...Combining with a bioinspired stereoselective dual hydrogenation, the divergent total synthesis of (+)‐3‐deoxyfortalpinoid F, (+)‐harringtonolide, (−)‐fortalpinoids M/N/P, and analog (−)‐20‐deoxocephinoid P have been achieved in 14‐17 linear longest steps starting from commercially available materials.
A series of selenium-containing clioquinol derivatives were designed, synthesized, and evaluated as multifunctional anti-Alzheimer’s disease (AD) agents. In vitro examination showed that several ...target compounds exhibited activities such as inhibition of metal-induced Aβ aggregation, antioxidative properties, hydrogen peroxide scavenging, and the prevention of copper redox cycling. A parallel artificial membrane permeation assay indicated that selenium-containing clioquinol derivatives possessed significant blood-brain barrier (BBB) permeability. Compound 8a, with a propynylselanyl group linked to the oxine, demonstrated higher hydrogen peroxide scavenging and intracellular antioxidant activity than clioquinol. Furthermore, 8a exhibited significant inhibition of Cu(II)-induced Aβ1–42 aggregation and was capable of disassembling the preformed Cu(II)-induced Aβ aggregates. Therefore, 8a is an excellent multifunctional promising compound for development of novel drugs for AD.
Abstract
STUDY QUESTION
Does the transplantation of adipose-derived stem cells (ADSCs) on soluble collagen scaffolds (collagen/ADSCs) have better therapeutic effect than transplantation of ADSCs ...alone, to treat premature ovarian insufficiency (POI) in a rat model induced by Tripterygium Glycosides (TG)?
SUMMARY ANSWER
The transplantation of collagen/ADSCs increased the short-term retention of ADSCs in ovaries and contributed to long-term restoration of ovarian function, as well as the fertility of rats with TG-induced ovarian damage.
WHAT IS KNOWN ALREADY
About 50% of young women in China, who have been treated with TG, have subsequently developed ovarian insufficiency. Rats exhibit similar symptoms to these patients when given an equivalent dose of TG. Transplantation of ADSCs improves ovarian function impaired by chemotherapy in rodent models.
STUDY DESIGN, SIZE, DURATION
After the administration of TG, 54 POI model rats were randomly assigned to 4 groups: phosphate buffered saline (PBS) (n = 14), collagen (n = 11), ADSCs (n = 16) and collagen/ADSCs (n = 13). Seventeen normal rats were assigned as control group. The retention of ADSCs in ovaries was confirmed immediately or at 3, 7, 14 and 28 days after transplantation (n = 9). Four weeks after transplantation, ovarian function was evaluated from estrous cycle, estradiol level, the follicle number, granulosa cell proliferation and a fertility test.
PARTICIPANTS/MATERIALS, SETTING, METHODS
To establish the POI model, rats were administered 60 mg TG/kg/day intragastrically for 50 days. The estrous cycles were assessed by vaginal smear. The concentration of plasma estradiol in diestrus stage was measured using a radioimmunoassay kit. Disordered estrous cycles and low serum estradiol levels indicated the successful establishment of the POI model. Four types of suspensions (PBS, collagen, ADSCs and collagen/ADSCs) were transplanted directly into the core of the ovaries. The short-term retention of ADSCs in ovaries was evaluated by small-animal positron emission tomography images immediately after transplantation of 18F-Fluorodeoxyglucose (18F-FDG) labeled ADSCs. The long-term retention of ADSCs in ovaries was observed by immunohistochemistry after transplantation of green fluorescent protein (GFP)-labeled ADSCs. Serial sections of ovaries were prepared for histological analysis, follicle counting, and immunohistochemistry for Ki67 and Cleaved-Caspase-3. For the assessment of fertility, rats were mated with proven fertile male rats for 10 days.
MAIN RESULTS AND THE ROLE OF CHANCE
The 18F-FDG signal decreased more slowly in ovaries injected with collagen/ADSCs than in ovaries with injected with ADSCs alone. Significantly more GFP-positive cells were observed in ovaries injected with collagen/GFP-ADSCs than in ovaries injected with GFP-ADSCs alone up to 14 days after the injection. However, in both groups very few GFP-positive cells were present at 4 weeks after transplantation. The collagen/ADSCs and ADSCs groups both showed better estrous cycle recovery than the PBS and collagen groups. The estradiol (E2) level in the collagen/ADSCs group was significantly increased compared with that of the PBS group (P < 0.05). The number of antral follicles in the collagen/ADSCs group and the ADSCs group significantly increased compared with the PBS group (P < 0.05). The granulosa cell proliferation in the collagen/ADSCs group was better than in the PBS group (P < 0.01). The mating rates of the collagen/ADSCs group (88.9%) and the ADSCs group (90.9%) were higher than that of PBS group (60%, P < 0.05). The pregnancy rates of the collagen/ADSCs group (77.8%) and the ADSCs group (72.7%) were higher than the PBS group (50%, P < 0.05).
LIMITATIONS, REASONS FOR CAUTION
We chose ADSCs for their accessibility, convenience and safety. We did not use other cells or materials for POI treatments to show that the collagen/ADSCs are the most promising materials.
WIDER IMPLICATIONS OF THE FINDINGS
Soluble collagen scaffolds may be useful in stem cells transplantation therapy for POI.
STUDY FUNDING/COMPETING INTEREST(S)
This work is supported by grants from the ‘Strategic Priority Research Program’ of the Chinese Academy of Sciences (XDA01030000); Maternal-Fetal Medicine from Jiangsu Province Health Department of China (XK2011027); Clinical Center of Obstetric, Gynecologic and Genetic Diseases, Nanjing Health Department of Jiangsu Province, China; Fundamental Research Funds for the Central Universities (20620140652). The authors declare no competing financial interests.
TRIAL REGISTRATION NUMBER
Not applicable.
Theaflavins are beneficial to human health due to various bioactivities. Biosynthesis of theaflavins using polyphenol oxidase (PPO) is advantageous due to cost effectiveness and environmental ...friendliness. In this review, studies on the mechanism of theaflavins formation, the procedures to screen and prepare PPOs, optimization of reaction systems and immobilization of PPOs were described. The challenges associated with the mass biosynthesis of theaflavins, such as poor enzyme activity, undesirable subproducts and inclusion bodies of recombinant PPOs were presented. Further strategies to solve these challenges and improve theaflavins production, including enzyme engineering, immobilization enzyme technology, water-immiscible solvent-water biphasic systems and recombinant enzyme technology, were proposed.
•Enzyme engineering can used to improve the properties of polyphenol oxidase.•Enzyme engineering and immobilized enzyme enhance yield of theaflavins.•Water-immiscible solvent-water biphasic systems can improve theaflavins production.•The subproducts can be reduced by controlling catechin composition and reaction time.•The use of fusion tags and molecular chaperones prevent formation of inclusion body.
With rapidly growing commercial markets of portable electronics, supercapacitors (SCs) have become one of the most promising energy storage devices due to their unique characteristics. However, the ...low energy densities severely restrict their practical application. Furthermore, the liquid-electrolyte has leak issues under deformation, resulting in device failure or performance degradation. Herein, a novel material which has a porous carbon (PC) nanostructure skeleton connected by tannic acid (TA) with Co metal compounds which can provide pseudocapacitance is designed. PC is derived by activation C
60
which is sp2 carbon that ensures the efficient transmission of electrons and Co metal compounds increase the active site of the Faraday redox reaction and improve the specific capacitance. TA makes porous carbon skeleton and Co metal compounds more closely linked, effectively improving ion transport efficiency and optimizing cycle performance. The composite showed a reversible specific capacity of 1475 mF cm
−2
at a charge/discharge current density of 2 mA cm
−2
and a specific capacity of 1174 mF cm
−2
at 30 mA cm
−2
when measured by a three-electrode system conducted in 2.0 M KOH electrolyte. In addition, the assembled solid-state symmetric SCs with the electrode materials have excellent cycling stability that cycled for 5000 cycles at 5 mA cm
−2
and the capacitance retention rate reached 95.76%. The device can also provide continuous and stable energy that lights up the red light-emitting diode (LED) with excellent bendability. This strategy provides a novel device design method and can be effectively applied to future flexible electronic products.
The use of whole-genome resequencing to obtain more information on genetic variation could produce a range of benefits for the dairy cattle industry, especially with regard to increasing milk ...production and improving milk composition. In this study, we sequenced the genomes of eight Holstein bulls from four half- or full-sib families, with high and low estimated breeding values (EBVs) of milk protein percentage and fat percentage at an average effective depth of 10×, using Illumina sequencing. Over 0.9 million nonredundant short insertions and deletions (indels) 1-49 base pairs (bp) were obtained. Among them, 3,625 indels that were polymorphic between the high and low groups of bulls were revealed and subjected to further analysis. The vast majority (76.67%) of these indels were novel. Follow-up validation assays confirmed that most (70%) of the randomly selected indels represented true variations. The indels that were polymorphic between the two groups were annotated based on the cattle genome sequence assembly (UMD3.1.69); as a result, nearly 1,137 of them were found to be located within 767 annotated genes, only 5 (0.138%) of which were located in exons. Then, by integrated analysis of the 767 genes with known quantitative trait loci (QTL); significant single-nucleotide polymorphisms (SNPs) previously identified by genome-wide association studies (GWASs) to be associated with bovine milk protein and fat traits; and the well-known pathways involved in protein, fat synthesis, and metabolism, we identified a total of 11 promising candidate genes potentially affecting milk composition traits. These were FCGR2B, CENPE, RETSAT, ACSBG2, NFKB2, TBC1D1, NLK, MAP3K1, SLC30A2, ANGPT1 and UGDH. Our findings provide a basis for further study and reveal key genes for milk composition traits in dairy cattle.
A Fourier domain mode locking (FDML) optoelectronic oscillator (OEO) scheme based on stimulated Brillouin scattering (SBS) is proposed to generate linearly chirped microwave waveforms (LCMWs) with ...excellent frequency sweep linearity and a precisely controllable frequency sweep range. The kernel of the proposed scheme is a center-frequency-definable SBS-based fast-tunable microwave photonic bandpass filter based on frequency-selective phase-to-intensity conversion, which is realized by using a single laser source to generate a fast frequency-swept probe light and a tunable pump light via electro-optic frequency shifting. A proof-of-concept experiment is carried out to demonstrate the proposed scheme, where LCMWs with flexibly-tunable center frequency and bandwidth are generated. In the experiment, the maximum time-bandwidth product and chirp rate are 82000 and 0.195 GHz/µs, respectively. Most importantly, the frequency deviation is less than 1 MHz and the frequency sweep linearity is smaller than 1.7%, which indicate that the proposed SBS-based FDML OEO can generate frequency-definable LCMWs with excellent frequency sweep linearity.
The focus of this study is to fabricate thermal management materials integrating thermal and electrical structural and functional materials by preparing graphene film reinforced Cu laminated ...composites. Strengthening the interface is a core scientific issue. Graphene is considered a good reinforcement phase because of its excellent electrical and thermal conductivity. The production route includes electroless Cu coating on graphene film and ball milling Cu powder into Cu flake. Due to the particularity of the film and the Cu flake through vacuum hot pressing sintering, laminated composite materials can be obtained. The transfer of electrons and internal energy within a material determines the electrical and thermal conductivity of the material. With the increase of content of graphene films, electrical properties of laminated composites and thermal conductivity on the plane direction increase, while the thermal conductivity on thickness direction decreases. The best thermal conductivity and electric conductivity can reach 457 W m−1 K−1 and 175 MS/m, respectively. However, when the graphene films contents exceed 30 vol%, the thermal conductivity in the plane direction decreases due to the severe interfacial cracks. In summary, copper coating on the graphene films surfaces can generally improve the interfacial bonding and thermal properties of laminated composites. It provides an effective method to perform the development of novel thermal management structures and functional materials.
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•The agglomeration of graphene can be improved by electroless Cu coating on graphene films.•The interface bonding can be improved by electroless Cu coating on graphene films.•The lamellar structure can improve the electrical and thermal properties of the composites.•The strengthening mechanisms mediated by lamellar structure were analyzed in detail.
ABSTRACT
The nature of the newly discovered fast blue optical transients (FBOTs) is still puzzling astronomers. In this paper, we carry out a comprehensive analysis of the molecular gas, ionized gas, ...and stellar populations in the environment of the nearby FBOT AT2018cow based on ALMA, VLT/MUSE, and HST/WFC3 observations. A prominent molecular concentration of 6 (± 1) × 106 M⊙ is found in the vicinity of AT2018cow, which has given rise to two active star-forming complexes with ages of 4 ± 1 and ≲2.5 Myr, respectively. Each star-forming complex has a stellar mass of 3 × 105 M⊙, and has photoionized a giant H ii region with Hα luminosity even comparable to that of the 30 Dor mini-starburst region. AT2018cow is spatially coincident with one of the star-forming complexes; however, it is most likely to reside in its foreground since it has a much smaller extinction than the complex. Its progenitor could have been formed in a different star-forming event, and the non-detection of the associated stellar population constrains the progenitor’s age to be ≳10 Myr and initial mass to be ≲20 M⊙. We further find the late-time brightness of AT2018cow is unlikely to be a stellar object. Its brightness has slightly declined from 2 to 4 yr after explosion and is most likely to originate from AT2018cow itself due to some powering mechanism still working at such late times.
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