Au25 Nanoclusters Incorporating Three-Dimensionally Ordered Macroporous In2O3 for Highly Sensitive and Selective Formaldehyde Sensing.

Detection of formaldehyde (FA) in the atmosphere is of significant importance because exposure to FA may cause serious health problems such as sick-house syndrome, leukemia, and cancer. Modifying metal oxide semiconductors (MOSs) with noble metal nanoparticles (NPs) is an efficient method to enhance FA-sensing properties. Herein, a series of Au25 nanocluster (NC)-decorated three-dimensionally ordered macroporous In2O3 materials (Au25/3DOM In2O3) is created, and the loading amount of Au25 NCs was optimized based on FA responses. To reveal the effect of gold size on FA responses, we constructed Au144 NC-loaded 3DOM In2O3 and Au NP (2.9 nm)-modified 3DOM In2O3 and compared their gas-sensing properties with the optimal Au25/3DOM In2O3. The results show that in comparison with its counterparts, the optimal Au25/3DOM In2O3 presents higher sensitivity, shorter response/recovery times, better selectivity, and excellent reproducibility. More attractively, the responses to FA are dependent on the size of Au particles loaded on In2O3. We suggest that the enhanced FA responses for the optimal material are mainly attributed to the electronic and chemical-sensitization effects of Au25 NCs, and the size-dependent effect of FA responses is ascribed to the size of Au NPs affecting the formation of oxygen-adsorbing species. This work provides an efficient way for fabricating noble metal NP-loaded MOSs with tunable gas-sensing properties.

Diketopiperazine and enterotoxin analogues from the mangrove derived-soil Streptomyces sp. SCSIO 41400 and their biological evaluation.

A new diketopiperazine, cyclo-(d-8-acetoxyl-Pro-l-Leu) (1), together with eight known compounds (2-9) including three enterotoxins (2-4), four diketopiperazines (5-8) and maltol (9), were isolated from the mangrove derived-soil Streptomyces sp. SCSIO 41400. The planar structures of all compounds were determined from analysis of NMR spectra, MS, optical rotation and comparing with literature data. The absolute configuration of compound 1 was assigned by electronic circular dichroism (ECD). The isolated compounds (1-9) were tested for their acetyl cholinesterase (AChE) and pancreatic lipase (PL) enzyme inhibitory activities. Among them, the new diketopiperazine (1) displayed preferable PL enzyme inhibitory activity with IC50 value of 27.3 µg/mL, while compounds 2, 5 and 6 showed weak PL enzyme inhibitory activity. Further molecular docking simulation exhibited that compound 1 could be well bind with the catalytic pocket of the PL. Besides, compound 9 showed moderate antibacterial activity against Methicillin-resistant Staphylococcus aureus with MIC value of 12.5 µg/mL, which was comparable to that of the positive control ampicillin with MIC value of 3.125 µg/mL.

Citrinin and α-pyrone derivatives with pancreatic lipase inhibitory activities from Penicillium sp. SCSIO 41302.

One new citrinin monomer derivative (1), and two new natural products α-pyrone analogues (2a and 2b), were isolated from the sponge derived fungus Penicillium sp. SCSIO 41302. Their structures were determined by extensive spectroscopic analysis, chiral-phase HPLC analysis, modified Mosher's method, ECD calculations, and X-ray single-crystal diffraction. Bioactivity screening showed that compounds 2b and 8 exhibited obvious inhibitory activities against pancreatic lipase and acetyl cholinesterase with IC50 values of 48.5 and 4.8 µM, respectively, which indicated that different chiral center between enantiomers (2a and 2b) might result in different biological activities (IC50 value against PL for 2a >100 µg/ml).

Selective Photocatalytic Reduction of CO2 to CH4 Modulated by Chloride Modification on Bi2WO6 Nanosheets.

Solar-driven photocatalytic CO2 reduction into CH4 with H2O is considered to be a promising way to alleviate the energy crisis and greenhouse effect. However, current CO2 photoreduction technologies tend to overlook the role of photooxidation half reaction as well as the effect of the protons produced by water oxidation on CH4 generation, resulting in low CO2 conversion efficiency and poor CH4 selectivity. In the present study, a series of chloride-modified Bi2WO6 nanosheets were constructed in view of chloride-assisted photocatalytic water oxidation. The results show that the CH4 yield of the synthesized sample can be enhanced up to about 10 times compared to that with no Cl- modification. Besides, the selectivity of CH4 can be regulated by the loading amount of chloride, varying from 51.29% for Bi2WO6 to 94.98% for the maximum. The increase of product yield is attributed to chloride modification, which not only changed the morphology of the catalyst, but also modified the pathway of water oxidation. Further studies on intermediate products and the density functional theory calculation confirm that the Cl- ions on Bi2WO6 nanosheets not only promote H2O oxidation, but also lower the energy barrier for intermediate *CHO generation, thus facilitating CH4 production. The results gained herein may provide some illuminating insights into the design of a highly selective photocatalyst for efficient CO2 reduction.

Tuning lithium-peroxide formation and decomposition routes with single-atom catalysts for lithium-oxygen batteries.

Lithium-oxygen batteries with ultrahigh energy density have received considerable attention as of the future energy storage technologies. The development of effective electrocatalysts and a corresponding working mechanism during cycling are critically important for lithium-oxygen batteries. Here, a single cobalt atom electrocatalyst is synthesized for lithium-oxygen batteries by a polymer encapsulation strategy. The isolated moieties of single atom catalysts can effectively regulate the distribution of active sites to form micrometre-sized flower-like lithium peroxide and promote the decomposition of lithium peroxide by a one-electron pathway. The battery with single cobalt atoms can operate with high round-trip efficiency (86.2%) and long-term stability (218 days), which is superior to a commercial 5 wt% platinum/carbon catalyst. We reveal that the synergy between a single atom and the support endows the catalyst with excellent stability and durability. The promising results provide insights into the design of highly efficient catalysts for lithium-oxygen batteries and greatly expand the scope of future investigation.

Process for a Free-Standing and Stable All-Metal Structure for Symmetrical Lithium-Oxygen Batteries.

A number of inherent and thorny obstacles still stand in the way of the practical application of Li-O2 batteries, which require development of an advanced lithium anode and O2 cathode. Herein, the strategy of a symmetrical Li-O2 battery is presented. Specifically, Cu nanoneedle arrays with a nanoengineered Au coating are grown directly on a Cu foam substrate (Au/Cu@FCu), which can act as both the anode backbone and the cathode in a Li-O2 battery. The excellent conductivity, high porosity, large specific surface, and superior lithiophilicity as well as high catalytic activity of the Au/Cu@FCu electrodes can simultaneously regulate the deposition behavior of the lithium metal in the anode and catalyze the formation/decomposition of Li2O2 in the cathode. As a result, the Li uniformly deposited on the Au/Cu@FCu anode without Li dendrites, showing a high Coulombic efficiency over 96% and a long and stable cycle lifetime over 970 h. At the same time, the Au/Cu@FCu cathode demonstrates extremely low overpotentials (0.64 V) and a much higher specific capacity of 27 270 mAh g-1 compared to the Li-O2 batteries with a carbon-free cathode reported to date. Moreover, the "ebb and flow" phenomenon of the anode and cathode morphology is also observed in the Li-O2 battery.

[Ecophysiological responses of Camellia japonica (Naidong) to different light and water conditions]. / è€å†¬å±±èŒ¶å¯¹ä¸åŒå ‰ç §å’Œæ°´åˆ†çš„ç”Ÿç†ç”Ÿæ€å­¦å“åº”.

Camellia japonica (Naidong), a Tertiary relict species with abundant morphological characteristics and special genetic characteristics, is the northernmost distributed population of C. japonica. The seedlings of Naidong were subjected to two light regimes (65%, 15% of full sunlight, respectively) and three water supply regimes (75%, 50% and 25% of field capacity, respectively). Our objectives were to reveal the ecophysiological responses of Naidong under different drought and shade conditions and to examine the four existing hypotheses explaining the responses of Naidong seedlings to the interactions of shade and drought. The results showed that 15% of full sunlight reduced the growth of seedlings. Compared with those under 65% of full sunlight condition, the net photosynthetic rate, transpiration rate and chlorophyll content of seedlings under 15% of full sunlight condition were decreased by 63.3%, 82.9% and 17.5%, respectively. In contrast, the specific leaf area, leaf water content and maximal quantum yield under 15% of full sunlight condition were enhanced by 60.3%, 8.3% and 6.4%, respectively. Drought limited the growth of seedlings,decreased their height and basal diameter. The net photosynthetic rate, transpiration rate and stomatal conductance of seedlings significantly decreased with the increases of drought stress, with their minimum values being 0.83 µmol·m-2·s-1, 0.30 µmol·m-2·s-1 and 11.56 mmol·m-2·s-1, respectively. With the increases of drought stress, the contents of peroxidase and catalase showed a general declining trend, but the contents of malondialdehyde and proline significantly increased. The treatment 15% of full sunlight alleviated the negative effects of drought on Naidong seedlings, which supported the above-ground facilitation hypothesis. Our results indicated that Naidong seedlings could respond and acclimate to environmental changes through various mechanisms, and the seedlings might normally grow under broad ranges of light and water stresses. In addition, providing ideal light and water conditions for the Naidong seedlings could facilitate its application in gardening.

In Situ Construction of Stable Tissue-Directed/Reinforced Bifunctional Separator/Protection Film on Lithium Anode for Lithium-Oxygen Batteries.

To achieve a high reversibility and long cycle life for Li-O2 battery system, the stable tissue-directed/reinforced bifunctional separator/protection film (TBF) is in situ fabricated on the surface of metallic lithium anode. It is shown that a Li-O2 cell composed of the TBF-modified lithium anodes exhibits an excellent anodic reversibility (300 cycles) and effectively improved cathodic long lifetime (106 cycles). The improvement is attributed to the ability of the TBF, which has chemical, electrochemical, and mechanical stability, to effectively prevent direct contact between the surface of the lithium anode and the highly reactive reduced oxygen species (Li2 O2 or its intermediate LiO2 ) in cell. It is believed that the protection strategy describes here can be easily extended to other next-generation high energy density batteries using metal as anode including Li-S and Na-O2 batteries.

Bioactive spirans and other constituents from the leaves of Cannabis sativa f. sativa.

In this paper, 17 compounds (1-17) were isolated from the leaves of Hemp (Cannabis sativa f. sativa). Among the isolates, two were determined to be new spirans: cannabispirketal (1), and α-cannabispiranol 4'-O-ß-D-glucopyranose (2) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known compounds 7, 8, 10, 13, 15, and 16 were isolated from Hemp (C. sativa f. sativa) for the first time. Furthermore, compounds 8 and 13 were isolated from the nature for the first time. All isolated compounds were evaluated for cytotoxicity on different tissue-derived passage cancer cell lines through cell viability and apoptosis assay. Among these compounds, compounds 5, 9 and 16 exhibited a broad-spectrum antitumor effect via inhibiting cell proliferation and promoting apoptosis. These results obtained have provided valuable clues to the understanding of the cytotoxic profile for these isolated compounds from Hemp (C. sativa f. sativa).

Ultrathin, Lightweight, and Wearable Li-O2 Battery with High Robustness and Gravimetric/Volumetric Energy Density.

An ultrathin, lightweight, and wearable Li-O2 battery with a novel segmented structure is first fabricated by employing a "break up the whole into parts" strategy. Superior battery performance including low overpotential, high specific capacity, good rate capability, excellent cycle stability, and high gravimetric/volumetric energy density (294.68 Wh kg-1 /274.06 Wh L-1 ) is successfully achieved even under repeatedly various deformation.

A Flexible and Wearable Lithium-Oxygen Battery with Record Energy Density achieved by the Interlaced Architecture inspired by Bamboo Slips.

A flexible and wearable lithium-oxygen (air) battery inspired by Chinese bamboo slips is constructed. In this novel battery, cathodes and anodes are woven without an air diffusion layer and any outer packaging; besides, the woven structure allows oxygen to access the cathodes from both sides freely, endowing the battery with a record energy density of over 523 W h kg-1 .

Macroporous Interconnected Hollow Carbon Nanofibers Inspired by Golden-Toad Eggs toward a Binder-Free, High-Rate, and Flexible Electrode.

Inspired by the favorable structure and shape of golden-toad eggs, a self-standing macroporous active carbon fiber electrode is designed and fabricated via a facile and scalable strategy. After being decorated with ruthenium oxide, it endows Li-O2 batteries with superior electrochemical performances.

Cable-Type Water-Survivable Flexible Li-O2 Battery.

A novel cable-type water-survivable flexible Li-O2 battery is developed with a hydrophobic and free standing gel polymer electrolyte. Superior battery performances are successfully achieved under mechanical twisting, bending, and even immersed in water conditions, showing the high promise to power next-generation versatile flexible electronics.

[Cold resistance of four evergreen broad-leaved tree species]. / å››ç§å¸¸ç»¿é˜”å¶æ ‘ç§çš„æŠ—å¯’æ€§.

The leaves of four evergreen plants, i.e., Fatsia japonica, Nerium indicum, Mahonia bealei and Acer cinnamomifolium were used as the experimental materials. By measuring the changes of in vitro leaf in soluble sugar, soluble protein, free proline, POD activity, chlorophyll content and relative electrolytic conductivity under aritificial simulated low temperature, combining the measurements of SPAD, leaf surface features and anatomical changes in organizational structure in the process of natural wintering, the cold resistance of four evergreen tree species was evaluated comprehensively. The results showed that in the process of artificial low temperature stress, the chlorophyll content of the leaves of four evergreen species decreased, the content of soluble protein pea-ked at -20 ℃, and the soluble sugar, free proline, POD activity and relative electrolytic conductivity showed an overall upward trend. The semilethal temperatures of four species were -8.0, -13.4, -19.4 and -14.8 ℃, respectively. During the winter, the leaf SPAD of the four species changed markedly, reflecting that the change of relative chlorophyll content was related to the change of temperature. Meanwhile, the leaf thickness, cutin layer thickness, stockade tissue thickness and tightness of four species increased and the plasmolysis occurred thereafter. Also the content of starch grains and calcium oxalate cluster crystal increased. The typical stomatal pits and the intensive non-glandular trichome within the pits of N. indicum and the sclerenchyma of M. Bealei could improve the cold resistance of plants to some extent. In addition, the phenomena like the breakage of wax layer in leaf surface, the fracture of epidermal hair and the deformation of palisade tissue indicated that plants were damaged to a certain extent by low temperature.

[Adaptability of Camellia sasanqua leaf morphology during natural changes in temperature.] / èŒ¶æ¢ å¶ç‰‡ç»“æž„å¯¹è‡ªç„¶å˜æ¸©çš„é€‚åº”.

In this study, the adaptability of leaf shape, structure and stomata characteristics of Camellia sasanqua to temperature variation in natural process was investigated by field morphological observation, conventional paraffin section and scanning electron microscopy methods. The results showed that, as the temperature decreased, the leaf color changed from green to dark green, toge-ther with white and purple spots on the leaves. The relative conductivity and the percentage of wi-thered leaves increased initially and then decreased during this period. The highest percentages of relative conductivity and withered leaves in March 2015 were 56.0% and 25.4%, respectively. Different leaf tissue structure indexes, including middle vein thickness, leaf thickness, upper and lower epidermis thickness, upper and lower cuticle thickness, palisade tissue thickness, spongy tissue thickness, ratio of palisade tissue to spongy tissue, cell tense ratio and vein protuberant degree were also determined during the natural temperature change from September 2014 to April 2015. Gradually, these parameters increased initially and then decreased with the decrease of temperature except spongy ratio, which showed the opposite trend. These indicators above changed significantly in different months. Stomata length and width were not significantly changed in October 2014, December 2014 and March 2015, while the percentage of completely closed stomata was higher in March 2015, compared with other months. Taken together, we proposed that the improved adaptability of cold tolerance of C. sasanqua relies on the changes of leaf structure and stomatal closure.

Flexible and Foldable Li-O2 Battery Based on Paper-Ink Cathode.

A flexible freestanding air cathode inspired by traditional Chinese calligraphy art is built. When this novel electrode is employed as both a new concept cathode and current collector, to replace conventional rigid and bulky counterparts, a highly flexible and foldable Li-O2 battery with excellent mechanical strength and superior electrochemical performance is obtained.

Flexible lithium-oxygen battery based on a recoverable cathode.

Although flexible power sources are crucial for the realization next-generation flexible electronics, their application in such devices is hindered by their low theoretical energy density. Rechargeable lithium-oxygen (Li-O2) batteries can provide extremely high specific energies, while the conventional Li-O2 battery is bulky, inflexible and limited by the absence of effective components and an adjustable cell configuration. Here we show that a flexible Li-O2 battery can be fabricated using unique TiO2 nanowire arrays grown onto carbon textiles (NAs/CT) as a free-standing cathode and that superior electrochemical performances can be obtained even under stringent bending and twisting conditions. Furthermore, the TiO2 NAs/CT cathode features excellent recoverability, which significantly extends the cycle life of the Li-O2 battery and lowers its life cycle cost.

Artificial Protection Film on Lithium Metal Anode toward Long-Cycle-Life Lithium-Oxygen Batteries.

An artificial while very stable solid electrolyte interphase film is formed on lithium metal using an electrochemical strategy. When this protected Li anode is first used in a Li-O2 battery, the film formed on the anode can effectively suppress the parasitic reactions on the Li anode/electrolyte interface and significantly enhance the cycling stability of the Li-O2 battery.

Synthesis and biological evaluation of oleanolic acid derivatives as PTP1B inhibitors.

Twenty-four sugar-substituted oleanolic acid derivatives (1a-1f, 2a-2j, and 3a-3h) were synthesized in a concise and efficient strategy and their effects on the inhibition of protein tyrosine phosphatase 1B (PTP1B) and insulin-sensitizing response were evaluated in vitro. Several derivatives showed moderate to good inhibitory activities against PTP1B, and especially compounds 2f, 2h, 3d and 3e exhibited the most potent inhibitory activities with the IC50 values of 1.91, 12.2, 9.21 and 0.56 µM against PTP1B, respectively. Furthermore, compounds 2g-2h and 3b-3e displayed good insulin-sensitizing activities with the response values ranging from 21.52% to 59.58%. Structure-activity relationship study of these sugar-substituted oleanolic acid derivatives demonstrated that PTP1B inhibitory activity and insulin-sensitizing response were strongly influenced by both the carbohydrate moiety at the C-3 position and the long acidic chain at C-28 position of oleanolic acid.