High yield electrosynthesis of oxygenates from CO using a relay Cu-Ag co-catalyst system.

As a sustainable alternative to fossil fuel-based manufacture of bulk oxygenates, electrochemical synthesis using CO and H2O as raw materials at ambient conditions offers immense appeal. However, the upscaling of the electrosynthesis of oxygenates encounters kinetic bottlenecks arising from the competing hydrogen evolution reaction with the selective production of ethylene. Herein, a catalytic relay system that can perform in tandem CO capture, activation, intermediate transfer and enrichment on a Cu-Ag composite catalyst is used for attaining high yield CO-to-oxygenates electrosynthesis at high current densities. The composite catalyst Cu/30Ag (molar ratio of Cu to Ag is 7:3) enables high efficiency CO-to-oxygenates conversion, attaining a maximum partial current density for oxygenates of 800 mA cm-2 at an applied current density of 1200 mA cm-2, and with 67 % selectivity. The ability to finely control the production of ethylene and oxygenates highlights the principle of efficient catalyst design based on the relay mechanism.

Tunability of the Superconductivity of NbSe2 Films Grown by Two-Step Vapor Deposition.

Layered metallic transition-metal dichalcogenides (TMDCs) are ideal platforms for exploring their fascinating electronic properties at two-dimensional limits, such as their charge density wave (CDW) and superconductivity. Therefore, developing ways to improve the crystallization quality of TMDCs is urgently needed. Here we report superconductively tunable NbSe2 grown by a two-step vapor deposition method. By optimizing the sputtering conditions, superconducting NbSe2 films were prepared from highly crystalline Nb films. The bilayer NbSe2 films showed a superconducting transition temperature that was up to 3.1 K. Similar to the salt-assisted chemical vapor deposition (CVD) method, superconducting monolayer NbSe2 crystals were also grown from a selenide precursor, and the growth strategy is suitable for many other TMDCs. Our growth method not only provides a way to improve the crystalline quality of TMDC films, but also gives new insight into the growth of monolayer TMDCs. It holds promise for exploring two-dimensional TMDCs in fundamental research and device applications.

The promises, challenges and pathways to room-temperature sodium-sulfur batteries.

Room-temperature sodium-sulfur batteries (RT-Na-S batteries) are attractive for large-scale energy storage applications owing to their high storage capacity as well as the rich abundance and low cost of the materials. Unfortunately, their practical application is hampered by severe challenges, such as low conductivity of sulfur and its reduced products, volume expansion, polysulfide shuttling effect and Na dendrite formation, which can lead to rapid capacity fading. The review discusses the Na-S-energy-storage chemistry, highlighting its promise, key challenges and potential strategies for large-scale energy storage systems. Specifically, we review the electrochemical principles and the current technical challenges of RT-Na-S batteries, and discuss the strategies to address these obstacles. In particular, we give a comprehensive review of recent progresses in cathodes, anodes, electrolytes, separators and cell configurations, and provide a forward-looking perspective on strategies toward robust high-energy-density RT-Na-S batteries.

Correction: Nitrogen-doped carbon nanotubes as an anode for a highly robust potassium-ion hybrid capacitor.

Correction for 'Nitrogen-doped carbon nanotubes as an anode for a highly robust potassium-ion hybrid capacitor' by Xiuqi Li et al., Nanoscale Horiz., 2020, DOI: .

Nitrogen-doped carbon nanotubes as an anode for a highly robust potassium-ion hybrid capacitor.

Potassium ion hybrid capacitors (KIHCs) have drawn growing interest owing to their outstanding energy density, power density and excellent cycling stability. However, the large ionic radius of potassium triggers a huge volume change during continuous K+ insertion/extraction processes, restricting the development of KIHCs. Here, we report N-doped carbon nanotubes (NCNTs) for high-performance K+ storage. The NCNTs possess a hierarchical structure and N functional groups and not only offer sufficient space to relieve the volume expansion, but also provide highly efficient channels to transport electrons and ions. As a result, the NCNTs anode presents a high specific capacity and an excellent cycling stability with an average decay rate of 0.0238% per cycle (the lowest value among the reported carbon-based anodes for K-ions batteries) during 3600 continuous cycles. A potassium ion hybrid capacitor (KIHC) was also designed with the NCNT anode and a commercial active carbon cathode and achieved both a high energy/power density (117.1 W h kg-1/1713.4 W kg-1) and a long cycle life (2000 cycles at 1 A g-1). Moreover, the in situ Raman and ex situ element mapping characterization demonstrate the outstanding electrochemical reversibility of the NCNTs. This work provides a superior strategy to design low-cost anode materials with excellent K+ storage electrochemistry.

Covalent Selenium Embedded in Hierarchical Carbon Nanofibers for Ultra-High Areal Capacity Li-Se Batteries.

Lithium selenium (Li-Se) batteries have attracted increasing interest for its high theoretical volumetric capacities up to 3,253 Ah L-1. However, current studies are largely limited to electrodes with rather low mass loading and low areal capacity, resulting in low volumetric performance. Herein, we report a design of covalent selenium embedded in hierarchical nitrogen-doped carbon nanofibers (CSe@HNCNFs) for ultra-high areal capacity Li-Se batteries. The CSe@HNCNFs provide excellent ion and electron transport performance, whereas effectively retard polyselenides diffusion during cycling. We show that the Li-Se battery with mass loading of 1.87 mg cm-2 displays a specific capacity of 762 mAh g-1 after 2,500 cycles, with almost no capacity fading. Furthermore, by increasing the mass loading to 37.31 mg cm-2, ultra-high areal capacities of 7.30 mAh cm-2 is achieved, which greatly exceeds those reported previously for Li-Se batteries.

Cocoon Silk-Derived, Hierarchically Porous Carbon as Anode for Highly Robust Potassium-Ion Hybrid Capacitors.

Potassium-ion hybrid capacitors (KIHCs) have attracted increasing research interest because of the virtues of potassium-ion batteries and supercapacitors. The development of KIHCs is subject to the investigation of applicable K+ storage materials which are able to accommodate the relatively large size and high activity of potassium. Here, we report a cocoon silk chemistry strategy to synthesize a hierarchically porous nitrogen-doped carbon (SHPNC). The as-prepared SHPNC with high surface area and rich N-doping not only offers highly efficient channels for the fast transport of electrons and K ions during cycling, but also provides sufficient void space to relieve volume expansion of electrode and improves its stability. Therefore, KIHCs with SHPNC anode and activated carbon cathode afford high energy of 135 Wh kg-1 (calculated based on the total mass of anode and cathode), long lifespan, and ultrafast charge/slow discharge performance. This study defines that the KIHCs show great application prospect in the field of high-performance energy storage devices.

In Situ Electrodeposited Synthesis of Electrochemiluminescent Ag Nanoclusters as Signal Probe for Ultrasensitive Detection of Cyclin-D1 from Cancer Cells.

Metal nanoclusters (NCs) as a new type of electrochemiluminescence (ECL) nanomaterials have attracted great attention, but their applications are limited due to relatively low luminescent efficiency and a complex preparation process. Herein, an ultrasensitive ECL biosensor for the detection of Cyclin-D1 (CCND1) was designed by utilizing in situ electrogenerated silver nanoclusters (AgNCs) as ECL emitters and Fe3O4-CeO2 nanocomposites as a coreaction accelerator. The ECL luminous efficiency of AgNCs on the electrode could be significantly enhanced with the use of the Fe3O4-CeO2 for accelerating the reduction of S2O82- to generate the strong oxidizing intermediate radical SO4•-. As a result, the assay for CCND1 detection achieved excellent sensitivity with a linear range from 50 fg/mL to 50 ng/mL and limit of detection down to 28 fg/mL. Impressively, the efficiency of Traditional Chinese Medicines (TCM), sophorae, toward MCF-7 cells was successfully investigated due to the overexpression of CCND1 in relation to the growth and metastasis of MCF-7 human breast cancer cells. In general, the proposed strategy provided an effective method for anticancer drug screening and expanded the application of metal NCs in ultrasensitive biodetection.

Increased expression of dermatopontin and its implications for testicular dysfunction in mice.

An array of specific and non­specific molecules, which are expressed in the testis, have been demonstrated to be responsible for testicular function. Our previous study revealed that dermatopontin (DPT) is expressed in Sertoli cells of the testis, however, its roles in testicular function remains somewhat elusive. In the present study, CdCl2­ and busulfan­induced testicular dysfunction models were used to investigate the implications of DPT expression for testicular function. The mRNA and protein expression levels of DPT were detected using reverse transcription­quantitative polymerase chain reaction and western blotting, respectively. A negative correlation was observed between testicular damage and the expression of DPT, which suggested that an increase in DPT expression may be a marker for testicular dysfunction. This result was corroborated by the finding that transgenic mice exhibiting Sertoli cell­specific overexpression of DPT exhibited damage to their testicular morphology. Additionally, DPT overexpression in the testis affected the expression levels of claudin­11 and zonula occludens­1, which indicated that DPT may affect testicular function by affecting the integrity of the blood­testis barrier (BTB). In conclusion, the present study provided evidence to suggest that DPT may be indicative of mouse testicular dysfunction, since increased expression may be associated with damage to the BTB.

Overexpression of PRL7D1 in Leydig Cells Causes Male Reproductive Dysfunction in Mice.

Prolactin family 7, subfamily d, member 1 (PRL7D1) is found in mouse placenta. Our recent work showed that PRL7D1 is also present in mouse testis Leydig cells, and the expression of PRL7D1 in the testis exhibits an age-related increase. In the present study, we generated transgenic mice with Leydig cell-specific PRL7D1 overexpression to explore its function during male reproduction. Prl7d1 male mice exhibited subfertility as reflected by reduced sperm counts and litter sizes. The testes from Prl7d1 transgenic mice appeared histologically normal, but the frequency of apoptotic germ cells was increased. Prl7d1 transgenic mice also had lower testosterone concentrations than wild-type mice. Mechanistic studies revealed that Prl7d1 transgenic mice have defects in the testicular expression of steroidogenic acute regulatory protein (STAR) and hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B). Further studies revealed that PRL7D1 overexpression affected the expression of transferrin (TF) in Sertoli cells. These results suggest that PRL7D1 overexpression could lead to increased germ cell apoptosis and exert an inhibitory effect on testosterone production in Leydig cells by reducing the expression of certain steroidogenic-related genes. In addition, PRL7D1 appears to have important roles in the function of Sertoli cells, which, in turn, affects male fertility. We conclude that the expression level of PRL7D1 is associated with the reproductive function of male mice.

Effects of icariin on reproductive functions in male rats.

The present study investigated the effects and potential mechanism(s) of action of icariin on the reproductive functions of male rats. Adult rats were treated orally with icariin at doses of 0 (control), 50, 100, or 200 mg/kg body weight for 35 consecutive days. The results show that icariin had virtually no effect on the body weight or organ coefficients of the testes or epididymides. However, 100 mg/kg icariin significantly increased epididymal sperm counts. In addition, 50 and 100 mg/kg icariin significantly increased testosterone levels. Real-time PCR suggests icariin may be involved in testosterone production via mRNA expression regulation of genes such as peripheral type benzodiazepine receptor (PBR) and steroidogenic acute regulatory protein (StAR). Furthermore, 100 mg/kg icariin treatment also affected follicle stimulating hormone receptor (FSHR) and claudin-11 mRNA expression in Sertoli cells. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured in the testes; 50 and 100 mg/kg icariin treatment improved antioxidative capacity, while 200 mg/kg icariin treatment upregulated oxidative stress. These results collectively suggest that icariin within a certain dose range is beneficial to male reproductive functions; meanwhile, higher doses of icariin may damage reproductive functions by increasing oxidative stress in the testes.

Dermatopontin is a novel regulator of the CdCl2-induced decrease in claudin-11 expression.

Cadmium (Cd) is a ubiquitous environmental heavy metal, which may be harmful to the reproductive functions through injury to the blood-testis barrier (BTB). However, the underlying mechanism of this adverse effect on the BTB remains uncharacterized. A preliminary study revealed that dermatopontin (DPT) expression was significantly increased in Cd chloride (CdCl2)-treated Sertoli cells in vitro, which suggested that an increase in DPT expression is crucial for CdCl2-induced BTB damage. To explore this further, in the present study we initially determined that DPT is expressed in testis Sertoli cells. The treatment of cells with CdCl2 resulted in a significant increase in DPT expression and a parallel decrease in claudin-11 expression, both in vivo and in vitro. To confirm the relationship between DPT and claudin-11, a DPT-silenced 15P-1 Sertoli cell model was established. We determined that DPT silencing could partly reduce the CdCl2-induced decrease in claudin-11 expression. Additionally, western blot analyses demonstrated that the p38 signaling pathway is involved in the effect of CdCl2 on DPT expression. In conclusion, the present study provides the first evidence that DPT may be a novel effector of CdCl2, highlighting the significant role of DPT in the regulation of claudin-11 expression.

Localization and expression patterns of prolactin-like protein J in mouse testis.

Prolactin (PRL)­like protein J (PLP­J) is a member of the prolactin family, mainly expressed in the placental decidua tissues of females, and is involved in gestation. To the best of our knowledge, it has not previously been shown to be expressed in males. Preliminary experiments of the present study indicated that PLP­J is expressed in the testis of male mice and is implicated in the regulation of testicular function. To definitively address whether PLP­J is expressed in the mouse testis, the expression pattern and cellular localization of PLP­J in mouse testes during postnatal development were characterized in the current study using molecular and immunological methods. Reverse transcription (RT)­polymerase chain reaction (PCR) was performed to amplify gene fragments from mouse testis specimens, which yielded sequences matching those of the PLP­J gene in Genbank. Subsequently, in situ hybridization showed that PLP­J was localized in interstitial tissue of the mouse testis. Immunofluorescence results indicated that PLP­J and 3ß­hydroxysteroid dehydrogenase 1 were colocalized in testis Leydig cells, confirming PLP­J expression in Leydig cells. In addition, PLP­J gene expression levels were examined at different stages of postnatal mouse development in male testis tissues using quantitative RT­PCR and western blotting. The results revealed that PLP­J expression levels were lowest in 18­day­old mice and highest in adults aged 4 months. Levels observed in 16­month­old individuals were lower than those observed in the 4­month­old mice, but remained significantly higher than the levels observed in 18­day­old mice. Furthermore, the roles of PLP­J in the murine testis TM3 Leydig cell line were studied. The results demonstrated that the upregulation of PLP­J expression in TM3 Leydig cells did not affect testosterone production or the cell cycle. In conclusion, this study demonstrated that PLP­J, a known member of the PRL family that was previously considered to be expressed solely in females, is also expressed in the testis of males with an age­dependent expression profile. Nevertheless, the physiological role of PLP­J in males remains unclear.

[Study on white light diffuse reflection spectrum of Chinese herbal medicine].

The white light diffuse reflection spectra of 57 kinds of Chinese herbal medicines were measured. Each of these spectra has some characteristics feature individually different from others. The spectra of those Chinese herbal medicines, whose medicinal sections are above ground (growing under sunlight), have a larger absorption peak in the region 650-690 nm than those under ground and inside herbal medicine body (growing isn't under sunlight, for example, the seeds). It was demonstrated that the white light diffuse reflection spectrum may be used to examine or distinguish Chinese herbal medicines as additional method and to control cultivation or growth of some Chinese herbal medicines.