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Erratic rainfall and misalignment between the rainy season and the growing season of winter wheat greatly limit rainfed winter wheat yield in the Loess Plateau of China. To increase the grain yield of winter wheat in this region, the effects of different agronomic practices, including adjusting planting pattern (NR, narrow row spacing), increasing seeding rate (high seeding rate, HS), decreasing basal nitrogen rate and increasing top-dressed nitrogen rate (DBN), and replacing an old cultivar with a new cultivar (NC) on wheat yield were investigated for two consecutive years. The results showed that the current grain yield of rainfed winter wheat in the Loess Plateau could be increased to 5879–7093 kg ha−1 by HS, DBN and NC practices relative to the practice of high-yielding farmers (PF). The increased yield due to HS, DBN and NC was attributed to the higher number of spikes ha−1, 1000-grain weight, and kernels spike−1. Before the flowering stage, HS increased soil water consumption (SWC) in 1–3 m subsoil due to the higher plant population compared with that of PF, whereas DBN decreased SWC in the 0–2 m soil layer compared with that of PF. After the flowering stage, HS, DBN, and NC increased SWC by 8–16 mm in 2–3 m subsoil compared to PF. The water use efficiency (WUE) was increased under DBN and NC in comparison with PF. However, the WUE did not increase under HS as it had the highest evapotranspiration among the five treatments. Increasing the use of subsoil water during the late growth stage by optimizing agronomic practices or applying new cultivars with expansive roots should be the primary approach to increase rainfed winter wheat yield in this region.

Aqueous zinc ion batteries employing metallic zinc anodes and aqueous electrolytes are highly attractive electrochemical energy storage devices owing to their cost effectiveness, intrinsic safety, elemental abundance and competitive gravimetric energy density. Compared with other cathode materials, vanadium-based compounds feature advantages such as higher capacity, higher power density and longer cycle life. Here, a comprehensive review is presented on recent advances of vanadium-based cathodes, focusing on the correlation between the structures and electrode performances as well as energy-storage mechanisms. The structure and electrochemical properties of vanadium-based cathode materials are discussed by categorizing Zn2+ diffusion channels including one-dimensional tunnels, two-dimensional planes, three-dimensional interpenetrating networks and zero-dimensional diffusion channels. Furthermore, the remaining issues of vanadium-based cathodes are highlighted and promising performance-enhancement strategies are overviewed from aspects such as lattice control, vacancy/defect engineering, and pre-intercalation of cations and/or molecules.

Enhancing the zinc ion storage ability of the existing cathodes is an important research field. Constructing the heterostructure is a promising and effective strategy. Interestingly, for oxygen-free cathodes, a nano-depth heterostructure layer will inevitably form on their surface when exposed to air. However, only the near-surface heterostructure interface cannot change their intrinsic zinc storage ability. Theoretically speaking, via constructing the bulk-type heterostructure with enough interfaces and grain boundaries, the intrinsic zinc storage ability of bulk cathodes can be effectively improved. Here, as a proof of concept, an operando conversion method to construct VS4/V2O3 heterostructures enabled by the extrinsic adsorbed oxygen is proposed. The successful preparation of VS4/V2O3 heterostructures is demonstrated via various characterization studies and analyses including X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, etc. Meanwhile, the obtained VS4/V2O3 heterostructures deliver an enhanced zinc ion storage capacity of 164 mA h g−1, rate performance and cycle stability. This operando construction approach enabled by extrinsic adsorbed oxygen provides a novel strategy to fabricate the functional heterostructure-based cathodes for multivalent ion batteries with high performance.

Hydrodynamic performance plays an important role on energy consuming and safety for autonomous underwater vehicles (AUVs). The hydrodynamics of the whole process of AUV free running pushed by a rot...

Quartz crystal microbalance (QCM) has attracted extensive attention in the field of biological analysis and detection because of its high sensitivity, fast response, real-time measurement, good operability, and low-cost production. However, to detect the trace amounts of small molecules, such as low-concentration saliva glucose under physiological conditions, is still a major challenge. Herein, the surface of a QCM chip was coated with a poly(boric acid)-based hydrogel using UV pressing-assisted polymerization to obtain a simple device for glucose detection. The designed QCM sensor shows a record-low detection limit of glucose (3 mg/L at pH 7.5), which is ∼30 times lower than that of sensors fabricated by conventional surface initiation-spin coating. The outperformance of the poly(boric acid) hydrogel-coated QCM sensor is probably due to the uniform and compact microstructure, as well as the presence of sufficient glucose-binding sites resulting from the hydrogel coating generated by UV pressing-assisted polymerization. This method provides an important solution to detect the trace amounts of small organic molecules or ions and has the potential to push forward the practical applications of QCM sensors.

Epidermal patterning factor 2 (EPF2) is a negative regulator of stomatal development, and is essential for plant growth, development, and environmental stress responses. However, the role of EPF2 in potato (Solanum tuberosum) has not been investigated to date. Here, we cloned and characterized the potato EPF2-like gene (StEPF2). StEPF2 is predominantly intercellular space localized and its transcripts were rhythmically expressed, and showed the highest expression in apical unexpanded leaves. Expression of StEPF2 was markedly down-regulated in response to abscisic acid and sodium chloride treatments; however, upon the application of polyethylene glycol, the expression of StEPF2 peaked at 4 h and then decreased gradually. Overexpression of StEPF2 in Arabidopsis (OE) substantially reduced stomatal density and photosynthetic rate, but had little effects on plant growth. Under drought stress, OE lines maintained higher photosynthetic rates, photosystem II efficiency, and instantaneous water use efficiency than wild-type (WT) plants. Moreover, OE lines showed less water loss and hydrogen peroxide accumulation in detached leaves compared with WT plants. Thus, our results suggest that StEPF2 acts as a negative regulator of stomatal development in potato, indicating that the role of EPF2 is conserved across plant species. Overall, StEPF2 represents an important target for the development of drought-tolerant potato cultivars via genetic engineering.

Global climate change is expected to cause progressively increased frequency and severity of drought events, which further seriously limit plant growth and crop yields. Increasing water use efficiency (WUE) and yield per unit rainfall are one of the most important challenges in dry land agriculture. Here, we reviewed the comprehensive technical strategies including conserving water to combine both increased agricultural productivity and resource conservation; enquiring into how crop plants respond to drought through morphological, physiological, and molecular modifications that occur in all plant organs; breeding for drought tolerance where there is a delineated stress environment and genotype × environment interactions are stable; effective conservation of rainfall and high efficiency of use. In addition, we discussed the preponderance of biological water-saving measures, which embraces improvements in WUE and drought tolerance, by genetic improvement and physiological regulation. Sustainable agriculture would be benefited from modern engineering such as biological engineering, conservation tillage, and breeding technologies.

It is always challenging to fabricate two-dimensional transition-metal dichalcogenides into multiple hollow micro-/nanostructures with improved properties for various potential applications. Here, hierarchically porous MoS2-C hollow rhomboids (MCHRs) have been creatively synthesized via a facile self-templated solvothermal approach. It has been clarified that the obtained MCHRs assembled beneath ultrathin γ-MnS and carbon cohybridized MoS2 nanosheets under the structural direction of the MnMoO4·0.49H2O self-template. The prepared MCHR anode of sodium-ion batteries exhibited a reversible capacity of 506 mA h g-1 at 0.1 A g-1, ultrahigh rate capabilities up to 10 A g-1 with 310 mA h g-1, and exceptional stability over 3000 cycles. This study provides inspiration for the rational design of hierarchically porous hollow nanostructures with specific geometries as an excellent electrode material for outstanding performance energy storage equipment.

New NiMoO4/CoMoO4 composite materials on Ni foam were successfully synthesized by a facile hydrothermal method using the mixture powers of Ni(NO3)2·6H2O and Co(NO3)2·6H2O as raw materials. The phase composition, microstructure, and morphology of the as-prepared composites were investigated by XRD, FTIR, SEM, EDS, and XPS. The electrochemical behaviors of the composites were tested by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The results indicated that the as-prepared composites are uniformly distributed on the surface of Ni foam with diameters between 2 and 3 μm, and the NiMoO4/CoMoO4 composite displays the best electrochemical properties when the molar ratio of Ni/Co is 1:1. In 3 mol L−1 KOH electrolytes with current densities of 1, 4, 7, and 10 A g−1, the discharge specific capacitance of NiMoO4/CoMoO4 composite is 2221, 1868, 1678, and 1568 F g−1, respectively, indicating its promising applications for high electrochemical performance energy storage device.

Benefiting from the high natural abundance and high theoretical specific capacities of potassium and sulfur, potassium–sulfur (K–S) batteries are deemed to be a promising energy storage system for large-scale energy storage applications. However, their application is hindered by poor kinetics due to the large radius of K+ ions and the notorious shuttling effect of soluble polysulfides as well as the lack of understanding of the underlying electrochemical reaction mechanism of sulfur with potassium. Here, a free-standing microporous carbon nanofiber/small-molecule sulfur composite is designed and fabricated, which provides fast kinetics, prevents the generation of soluble polysulfides, and creates strong chemical and physical confinement to sulfur. Unprecedented electrochemical performance is demonstrated with a high reversible capacity of 1392 mA h g−1 and ultra-stable cycling performance with 88% capacity retention after 2000 cycles. More importantly, the storage chemistry is systematically explored by multiple characterization techniques, including high-resolution transmission electron microscopy, sulfur K-edge X-ray absorption near-edge structure spectroscopy and ex situ X-ray photoelectron spectroscopy, and K2S is verified as the final potassiation product. The findings provide a fundamental understanding of the reaction mechanism and will guide the material design for high performance K–S batteries.

A glucose-sensitive hydrogel coated on a quartz crystal microbalance (QCM) sensor makes an important integrated system for achieving a continuous glucose monitoring system for diabetes, attributed to its high repeatability, rapid response time, and wide detection range. However, the poor viscoelasticity of the functional hydrogel film usually leads to the transport of water molecules out of the hydrogel matrix owing to the increased crosslinking density by molecular recognition, thus resulting in poor stability and limit of detection (LOD) of the hydrogel-coated QCM sensor, which limits its practical application in the detection of saliva glucose in low concentrations. Herein, this problem is solved by copolymerizing a rigid phenylboronic acid-containing graphene oxide (GO)-based monomer with a glucose-sensitive monomer (i.e., 3-acrylamidophenylboronic acid (3-APBA)) onto a double bond-modified QCM chip to fabricate a hybrid hydrogel-coated QCM sensor with improved viscoelasticity. Moreover, the 3-aminophenylboronic acid-grafted GO provides more reaction sites toward glucose, which is found to be beneficial for further improving the LOD of the hydrogel-coated QCM sensor. The experimental results show that the LOD of the hybrid hydrogel film (1 mg L−1) is about 10-fold and 900-fold lower than that of the hydrogel film (10 mg L−1) and polymer brushes (900 mg L−1) respectively. This study provides a new approach for continuous sensing of saliva glucose using a highly sensitive hybrid hydrogel-coated QCM sensor with improved properties, which contributes to the diagnosis, monitoring, and formulation of an appropriate treatment plan for patients suffering with diabetes.

Age determination of necrophagous flies serves as an important tool for postmortem interval (PMI) estimation in forensic investigations. Drugs or toxins in cadavers may alter the developmental time of larvae, and lead to deviation in PMI estimation. Methamphetamine (MA), as one of the most abused psychostimulant drugs in Asia and North America, is often involved in forensic entomotoxicological cases. This study investigated the effects of MA (0, 45, 90, and 180 ng/mg) on the developmental rate, morphology, and survival of Aldrichina grahami (Aldrich, 1930). The results showed that 1) the developmental time to reach the pupal instar was statistically slower for the larvae reared on rabbit mince containing MA than for the control; 2) the mean length of the larvae exposed to MA concentrations was longer than those of the control; 3) the mean weight of the pupae exposed to the highest concentration of MA was significantly lighter than those of the control; 4) the GC–MS method can detect the content of MA in A. grahami immatures and empty puparia (EP).

To reach a closed-loop material system and meet the urgent requirement of sustainable energy storage technologies, it is essential to incorporate efficient waste management into designing new energy storage materials. Here, a “two birds with one stone” strategy to transform rusty iron products into Prussian blue as high-performance cathode materials, and recover the rusty iron products to their original status, is reported. Owing to the high crystalline and Na+ content, the rusty iron derived Prussian blue shows a high specific capacity of 145 mAh g−1 and excellent cycling stability over 3500 cycles. Through the in situ X-ray diffraction and in situ Raman spectra, it is found that the impressive ion storage capability and stability are strongly related to the suppressed structure distortion during the charge/discharge process. The ion migration mechanism and the possibility to serve as a universal host for other kinds of ions are further illuminated by density functional theory calculations. This work provides a new strategy for recycling wasted materials into high value-added materials for sustainable battery systems, and is adaptable in the nanomedicine, catalysis, sensors, and gas storage applications.

To visit the electrochemical properties of sodium-based phosphate as a cheap cathode material for lithium ion batteries, a facile domestic microwave irradiation route has been adopted to rapidly synthesize Na3V2(PO4)3 material in 15 min. Here, the nitrogen-doping carbon has been introduced into in-situ preparation of Na3V2(PO4)3/carbon composites and its influence on electrochemical properties of Na3V2(PO4)3 was systemically studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectra. Results showed that the obtained nitrogen-doping carbon coated Na3V2(PO4)3 possesses excellent C-rate capacity performances, which are 104.5, 97.7, 97.5, 96.3, 94.1, 89.5 and 83.6 mAh g−1 at 0.1, 0.2, 0.5, 1, 2, 5 and 10 C, respectively. More importantly, the composite still possesses high capacity retention of 86.6% after 500 cycles at 5C. Electrochemical impedance spectroscopy profiles reveal that nitrogen-doing carbon strategy can efficiently alleviate the charge-transfer impedance of Na3V2(PO4)3. The improved electrochemical performance can be mainly ascribed to the unique structure, rapid microwave irradiation strategy and suitable nitrogen-doping content.

Melatonin (MEL) has been widely reported to be beneficial to plant growth and development, but few studies have combined investigations of the performance and function of MEL with detailed physiologically based analyses of nitrogen (N) uptake and metabolism in staple crops. In this study, the effect of MEL application on winter wheat seedling growth and grain yield were investigated in hydroponic and pot experiments at different N levels. The result showed that application of 1 μM MEL in hydroponic solution significantly improved the wheat seedling growth under both N sufficient and deficient conditions, but the effect of MEL on promoting seedling growth was prominent under N deficient condition. Meanwhile, MEL-treated plants maintained higher N contents and nitrate nitrogen levels in shoot under N deficient condition, and also maintained higher nitrate nitrogen levels in root. Further investigation showed that nitrate reductase (NR) and glutamine synthetase (GS) activities were higher in MEL-treated plants than that of MEL-untreated plants under N deficiency. The N absorption calculated based on N contents and biomass showed that MEL could promote the N absorption under N deficient condition. In pot experiment, pre-soaking of seeds with 100 μM MEL enhanced per-plant yield by 16% under N sufficient condition and 23% under N deficient condition. Taken together, the results of this study indicate that MEL is involved in promoting N uptake and assimilation through up-regulating the activities of N uptake and metabolism related enzymes and, ultimately, promotes the plant growth and yield, especially under N deficient condition.

Novel NiMoO4-integrated electrode materials were successfully prepared by solvothermal method using Na2MoO4·2H2O and NiSO4·6H2O as main raw materials, water, and ethanol as solvents. The morphology, phase, and structure of the as-prepared materials were characterized by SEM, XRD, Raman, and FT-IR. The electrochemical properties of the materials in supercapacitors were investigated by cyclic voltammetry, constant current charge–discharge, and electrochemical impedance spectroscopy techniques. The effects of volume ratio of water to ethanol (W/E) in solvent on the properties of the product were studied. The results show that the pure phase monoclinic crystal NiMoO4 product can be obtained when the W/E is 2:1. The diameter and length are 0.1–0.3 µm and approximately 3 µm, respectively. As an active material for supercapacitor, the NiMoO4 nanorods material delivered a discharge specific capacitance of 672, 498, and 396 F/g at a current density of 4, 7, and 10 A/g, respectively. The discharge specific capacitance slightly decreased from 815 to 588 F/g with a retention of 72% after 1000 cycles at a current density of 1 A/g. With these superior capacitance properties, the novel NiMoO4 integrated electrode materials could be considered as promising material for supercapacitors.

In this paper, highly active Ag catalysts supported on carbon nanotubes (CNTs) were synthesized by impregnation and two kinds of simple one step co-reduction methods with reducing agents of glycerol and dimethyl sulfoxide (denoted as IM, GL and DMSO sample). The catalysts were characterized by N2 adsorption–desorption, X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy, transmission electron microscopy, UV–visible spectrometer, infrared spectrometry, X-ray photoelectron spectroscopy (XPS) and H2 temperature programmed reduction (H2-TPR). DMSO sample showed the high reaction activity, above 90% HCHO conversion at 150 °C, whereas its surface Ag content is only less than ten times of IM sample in DMSO sample. The XRD, SEM, BET analysis, XPS and H2-TPR results revealed that the highly dispersed Ag/CNTs prepared by chemical reduction method in DMSO sample showed a smaller silver particles size, high surface areas and the enriched surface oxygen species. In general, the highest activity of DMSO samples in HCHO oxidation was associated with its higher silver dispersion and the strong interaction between Ag and CNTs, thereby increasing the effectiveness of oxygen mobility.

Late embryogenesis abundant (LEA) proteins are small, highly hydrophilic proteins that act as protectors of macromolecules and increase abiotic stress tolerance in plants. We previously reported that overexpressing sweetpotato IbLEA14 under the control of the CaMV 35S promoter increased osmotic and salt stress tolerance in transgenic sweetpotato calli. In this study, we generated transgenic poplar plants (Populus alba × P. glandulosa) expressing IbLEA14 under the control of the oxidative stress-inducible SWPA2 promoter (referred to as SL plants). Among the 15 SL plants obtained, three lines (SL2, SL7, and SL12) were established based on IbLEA14 transcript levels, tolerance to salt stress and Southern blot analysis. The SL plants exhibited less damage in response to methyl viologen-mediated oxidative stress than non-transgenic (NT) plants. SL plants also showed enhanced tolerance to drought, salt, and heat stress, which was associated with higher photosystem II efficiency and lower malondialdehyde levels compared with NT plants. Furthermore, SL plants had higher levels of monolignol biosynthesis-related gene transcripts under drought stress compared with NT plants. Finally, SL plants exhibited increased tolerance to heat stress, which is associated with the high thermostability of IbLEA14 protein. SL plants might be useful for reforestation on global marginal lands, including desertification and reclaimed areas.

Saliva glucose detection based on a quartz crystal microbalance (QCM) sensor has emerged as a promising tool and a non-invasive diagnostic technique for diabetes. However, the low glucose concentration and strong protein interference in the saliva hinder the QCM sensors from practical applications. In this study, we present a robust and simple anti-fouling CNT-PEG-hydrogel film-coated QCM sensor for the detection of saliva glucose with high sensitivity. The CNT-PEG-hydrogel film consists of two layers; the bottom base PBA-hydrogel film is designed to recognize the glucose while the top CNT-PEG layer is used to restrict protein adsorption and improve the biocompatibility. Our results show that this CNT-PEG-hydrogel film exhibited a 10-fold enhancement on the detection limit compared to the PBA-hydrogel. Meanwhile, the adsorption of proteins on the surface of the CNT-PEG-hydrogel film, including bovine serum albumin (BSA), mucin (MUC), and fibrinogen (FIB), were reduced by 99.1%, 77.8%, and 83.7%, respectively. The CNT-PEG-hydrogel film could detect the typical saliva glucose level (0–50 mg L−1) in 10% saliva with a good responsivity. To sum up, this new tool with low-fouling film featuring high stability, specificity, and selectivity holds great potential for non-invasive monitoring of saliva glucose in human physiological levels.

Cadmium (Cd) is widespread in the soil, water, and atmosphere, so Cd toxicity to human can happen by breathing in air, drinking water, and eating food from plant grown in Cd-contaminated soil. Cd pollution draws a lot of attention from the scientific community and also regulatory agents and is researched widely by using both plant and animal system. In this protocol, the detection of cadmium (Cd) is described in soil and mature maize (Zea mays) plant with the atomic absorption spectrometer. The Cd uptake, translocation factor, and Cd health risk index are also introduced. The protocol can be modified slightly to measure Cd in different types of plants.

Background Nitrogen (N) deficiency is a major constraint for plant production in many areas. Developing the new crop genotypes with high productivity under N deficiency is an important approach to maintain agricultural production. Therefore, understanding how plant response to N deficiency and the mechanism of N-deficiency tolerance are very important for sustainable development of modern crop production. Results In this study, the physiological responses and fatty acid composition were investigated in 24 wheat cultivars under N-deficient stress. Through Pearson’s correlation analysis and principal component analysis, the responses of 24 wheat cultivars were evaluated. The results showed that the plant growth and carbohydrate metabolism were all differently affected by N deficiency in all tested wheat cultivars. The seedlings that had high shoot biomass also maintained high level of chlorophyll content under N deficiency. Moreover, the changes in fatty acid composition, especially the linolenic acid (18:3) and the double bond index (DBI), showed close positive correlations with the shoot dry weight and chlorophyll content alterations in response to N-deficient condition. These results indicated that beside the chlorophyll content, the linolenic acid content and DBI may also contribute to N-deficiency adaptation, thus could be considered as efficient indicators for evaluation of different response in wheat seedlings under N-deficient condition. Conclusions The alteration in fatty acid composition can potentially contribute to N-deficiency tolerance in plants, and the regulation of fatty acid compositions maybe an effective strategy for plants to adapt to N-deficient stress.

Melatonin has been confirmed extensively for the positive effects on increasing plant tolerance to various abiotic stresses. However, the roles of melatonin in mediating different stresses still need to be explored in different plants species and growth periods. To investigate the role of melatonin in mitigating salt stress, maize (Zea mays L.) seedlings growing in hydroponic solution were treated with 100 mM NaCl combined with or without 1 &mu, M melatonin. Melatonin application had no effects on maize growth under normal condition, while it moderately alleviated the NaCl-induced inhibition of plant growth. The leaf area, biomass, and photosynthesis of melatonin-treated plants were higher than that of without melatonin under NaCl treatment. The osmotic potential was lower, and the osmolyte contents (including sucrose and fructose) were higher in melatonin-treated plants. Meanwhile, the decreases in Na+ content and increases in K+/Na+ ratio were found in shoots of melatonin-applied plant under salt stress. Moreover, both enzymatic and nonenzymatic antioxidant activities were significantly increased in leaves with melatonin application under salt treatment. These results clearly indicate that the exogenous melatonin-enhanced salt tolerance under short-term treatment could be ascribed to three aspects, including osmotic adjustment, ion balance, and alleviation of salt-induced oxidative stress.

Background Water deficiency is likely to become more frequent and intense as a result of global climate change, which may severely impact agricultural production in the world. The positive effects of melatonin (MEL) on alleviation drought or osmotic stress-induced water deficiency in plants has been well reported. However, the underlying mechanism of MEL on the detailed process of plant water uptake and transport under water deficiency condition remains largely unknown. Results Application of 1 μM MEL led to enhanced tolerance to water deficiency stress in maize seedlings, as evidenced by maintaining the higher photosynthetic parameters, leaf water status and plant transpiration rate. The relatively higher whole-plant hydraulic conductance (Kplant) and root hydraulic conductance (Lpr) in MEL-treated seedlings suggest that exogenous MEL alleviated water deficiency stress by promoting root water absorption. HgCl2 (aquaporin inhibitor) treatment inhibit the transpiration rate in MEL-treated plants greater than those of MEL-untreated; after recovery by dithiothreitol (DTT, anti-inhibitor), the transpiration rate in MEL-treated plants increased much higher than those of untreated plants. Moreover, under water deficiency, the transcription level of aquaporin genes was up-regulated by MEL application, and the H2O2 was less accumulated in MEL-treated root. Conclusions Exogenous MEL promoted aquaporin activity, which contributed to the maintaining of Lpr and Kplant under short-term water deficiency. The increased water uptake and transport lead to improved water status and thus increased tolerance to PEG-induced short-term water deficiency in maize seedlings.

Sarcophaga dux (Diptera: Sarcophagidae) is a necrophagous flesh fly species with potential forensic value for estimating minimum postmortem interval (PMImin). The basic developmental data and precise age estimates of the pupae are significant for PMImin estimation in forensic investigations. In the present study, we investigated the development data of that species at seven constant temperatures varying from 16 °C to 34 °C, including body length changes of the larve, developmental duration and accumulated degree hours of the preadults. Several reference genes for relative quantification of the differentially expressed genes (DEGs) were firstly selected and evaluated in the pupae of different ages under different temperatures. The DEGs of the insects during the pupal period at different constant temperatures (34, 25 and 16 °C) were further analyzed for more precise age estimation. The results showed that the developmental durations of the preadults at 16, 19, 22, 25, 28, 31 and 34 °C were 1478.6 ± 18.3 h, 726.1 ± 15.8 h, 538.5 ± 0.9 h, 394.1 ± 9.5 h, 375.6 ± 10.8 h, 284.1 ± 7.3 h, and 252.5 ± 6.1 h, respectively. The developmental threshold temperature the flies was 12.27 ± 0.35 °C, and the thermal summation constant was 5341.71 ± 249.29° hours. The most reliable reference genes during the pupal period at different temperatures were found: GST1 and 18S rRNA for the 34 °C group, GST1 and RPL49 for 25 °C, and 18S rRNA and 28S rRNA for 16 °C. The four differential expression genes (Hsp60, A-alpha, ARP, and RPL8) have the potential to be used for more precise age estimation of pupal S. dux. This work provides important basic developmental data and a more precise age estimation method for pupal S. dux, and improves the value of this species for PMImin estimation in forensic investigations.

Cadmium (Cd) contamination is a serious threat to plants and humans. Application of silicon (Si) or nitric oxide (NO) could alleviate Cd accumulation and toxicity in plants, but whether they have joint effects on alleviating of Cd accumulation and toxicity are not known. Therefore, the combined effect of Si and NO application on maize growth, Cd uptake, Cd transports and Cd accumulation were investigated in a pot experiment. Here, we reported that Cd stress decreased growth, caused Cd accumulation in plants. The combined application of Si and NO triggered a significant response in maize, increasing plant growth and reducing Cd uptake, accumulation, translocation and bioaccumulation factors under Cd stress. The grain Cd concentration was decreased by 66 % in the Si and NO combined treatment than Cd treatment. Moreover, the combined application of Si and NO reduced Cd health risk index in maize more effectively than either treatment alone. This study provided new evidence that Si and NO have a strong joint effect on alleviating the adverse effects of Cd toxicity by decreasing Cd uptake and accumulation. We advocate for supplement of Cd-contaminated soil with Si fertilizers and treatment of crops with NO as a practical approach to alleviating Cd toxicity.

The effects of exogenous application of melatonin (MEL) on promoting plant growth and alleviating environmental stresses are already known, but the potential value in crop production is still poorly understood. In this study, the effects of seed pre-soaking with MEL on winter wheat (Triticum aestivum L.) growth and yield were investigated in a continuous two-year pot experiment and another year of field experimentation. Results showed that seed pre-soaking with different concentrations of MEL (10, 100 and 500 &mu, M) for 24 h increased grain yields per plant from 29% to 80% in pot experiment and increased grain yield per area from 4&ndash, 19% in field experiment, compared with the controls. Further analysis showed that the beneficial effects of MEL on improving wheat grain yield can be ascribed to: (1) increased spike number by enhancing tiller number, (2) enhanced carbon assimilation capacity by maintaining large leaf area, high photosynthetic rate and delaying leaf senescence, (3) promoted growth in root system. The result of this study suggests that MEL could be considered as an effective plant growth regulator for improving grain production in winter wheat.

Alterations in membrane lipid composition lead to improved plant salt tolerance. Gibberellic acid (GA3) has also been widely reported to reduce growth inhibition induced by increased salinity. However, little is known about whether exogenous application of GA3 participates in up-regulation of lipid biosynthesis under salt stress. In this study, one of the major lipid biosynthesis genes in rice (Oryza sativa L. cv. Nipponbare), monogalactosyldiacylglycerol synthase (OsMGD) was found to be significantly up-regulated by GA3 treatment. Lipid analysis showed that after salt disturbance, the concentrations of all the measured lipids, including monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG) and phospholipid lipids + sulfoquinovosyl diacylglycerol (PL + SQDG) were decreased significantly. However, GA3 treatment prior to salt disturbance caused those lipids to remain at high levels, as well as preserving a high DGDG/MGDG ratio. The desaturation of DGDG (DBI) was also increased in GA3 pre-treatment plants as compared with no GA3 pre-treatment, primarily due to a decrease of 16:0 fatty acids and an increase of 18:3 fatty acids in DGDG. Plants pre-treated with GA3 prior to salt disturbance had higher dry weights than those without pre-treatment. The chlorophyll concentration was also higher in GA3 treated plants than in untreated plants under salt disturbance. Taken together, these results indicate that exogenous application of GA3 participates in up-regulation of chloroplast lipid biosynthesis under salt disturbance in rice.

A polylaminate coating with intersecting tantalum and tantalum nitride (TaN/Ta/TaN/Ta/TaN/Ta, TaN is the outermost layer) is deposited on surface of 430 stainless steel bipolar plate for high temperature proton exchange membrane fuel cell by a reactive magnetron sputtering method. Electrochemical tests including potentiodynamic, potentiostatic polarisation and electrochemical impedance spectroscopy, are carried out to evaluate the corrosion resistance and stability of the polylaminate TaN/Ta coating in simulating high temperature proton exchange membrane fuel cell environments (85% H 3 PO 4 solution at 80 °C and 130 °C). Results show that the polylaminate TaN/Ta coating greatly improve the corrosion resistance of 430 stainless steel, which can provide almost 100% protection of the substrate in both high temperature proton exchange membrane fuel cell anode and cathode environment. Besides, the interfacial contact resistance of coated 430 stainless steel (9.03 mΩ cm 2 ) is much lower than that of bare substrate (106.74 mΩ cm 2 ). Furthermore, different from the highly increased interfacial contact resistance of bare specimen, the coated 430 stainless steel shows a minor increase resistance after potentiostatic tests in 85% H 3 PO 4 solution at 130 °C.

Drought triggers leaf senescence, leading to a critical decrease in crop yield. The membrane lipid composition generally undergoes major changes during drought. However, little is known about the role of galactolipid remodeling in the drought-induced senescence response in crops. Here, a comparative study of alterations in galactolipid and fatty acid composition during drought and recovery was carried out using two maize cultivars differing in drought-induced leaf senescence. Under drought condition, the monogalactosyldiacylglycerol (MGDG) content was decreased by 18.3% and 25.9% in the cultivar with retarded leaf senescence and the senescent cultivar, respectively, while digalactosyldiacylglycerol (DGDG) was enhanced by 43.2% and 22.9%. Compared with the senescent cultivar, the DGDG content and the DGDG/MGDG ratio were 29.8% and 20.7% higher in the cultivar with retarded leaf senescence, which also maintained stable chloroplast ultrastructure under drought stress. The expressions of key galactolipid biosynthesis genes in both cultivars were up-regulated by the drought stress. In addition, the expression levels were higher in the cultivar with retarded leaf senescence than that in the senescent cultivar. These results suggests that a profound modification of galactolipid composition with high DGDG content and DGDG/MGDG ratio is associated with the alleviation of leaf senescence in response to drought. The regulation of galactolipid remodeling could be a promising strategy for alleviating the leaf senescence and improving drought adaptation in crops.

In recent years, with the rapid economic development, real-time monitoring of human health has received extensive attention. Wearable health monitoring equipment with good malleability and resistance to distortion makes great progress. The flexible supercapacitors integrated into the textile are characterized by a simple production process, low cost, fast charge,-discharge speed, and long cycle life. Therefore it has superior performance and broad research prospects. This review mainly introduces the recent advances and challenges of flexible supercapacitors, focusing on various flexible substrates' synthesis and performance. It summarizes the most representative flexible electrode materials at this stage. The future development trend and direction of flexible supercapacitors are discussed as well. Finally, the challenges in practical applications are considered.

Nickel-zinc batteries have obvious advantages such as high safety, environmental friendship, and high energy density, making them as the most promising alternatives to replace the traditional lead-acid batteries. However, the notorious zinc dendrite issue seriously hinders the development of the nickel-zinc battery. Considering In2O3 can inhibit zinc dendrite effectively, hence it is important to obtain the zinc electrode with uniformly dispersed In2O3. Here, via applying an operando non-topological conversion reaction of ZnIn2S4, the zinc oxide composite anode with evenly distributed In2O3 can be constructed. Through a series of characterizations such as X-ray diffraction, scanning/transmission electron microscopes, and X-ray photoelectron spectroscopy, the operando non-topological conversion reaction from ZnIn2S4 precursor to ZnO@In2O3 can be directly demonstrated. Meanwhile, as the nickel-zinc battery anode, the obtained ZnO@In2O3 can achieve the high specific capacity (520 mAh g−1), high rate performance, and long cycle stability. This operando non-topological conversion strategy provides a new approach for designing the high-performance electrode materials.

The application of green manure is a traditional and valuable practice for agroecosystem management. In northern China, the effects of green manure on production of the region’s major crops have been extensively investigated, but the inconsistent conclusions that these case studies have yielded cannot provide effective guidance for practical local agricultural production. Here, we conducted a meta-analysis to generate a comprehensive evaluation of the effects of green manure on soil properties and crop yield in this region. Our results shown that green manure improves soil quality effectively, decreasing soil bulk density by ∼ 5.6 %, increasing microbial biomass carbon by 28 %, and improving the activities of soil enzymes by 14 % ∼ 39 %. Among the different types of green manure, legume green manure more markedly increased both nitrate and hydrolysable nitrogen, while non-legume green manure more markedly increased available potassium. Soil gravimetric water content was decreased under green manure treatment. Maize yield was significantly increased under green manure by 11 % on the whole, while effects of green manure on wheat and potato were inconsistent. In summary, the application of green manure in northern China can improve soil quality significantly, and proper green manure use can improve cash crop yields.

Harvesting ambient mechanical energy is a crucial method to gain low-cost, clean and sustainable electric energy for self-powered electronics. Herein, we develop a freestanding-electret rotary generator and the explicit analytical solutions of the output current, voltage and average power are obtained from its theoretical model. The maximum average output power and the matched load resistance can be estimated directly from simple formulas. The generator using an inexpensive micro-nano-structured PTFE electret film achieves an open-circuit voltage with an amplitude of 650 V and a conversion efficiency about 56% with 10.5 mW output power at a rotation rate of 750 rpm. We find that the opposite charges injected into the back of the electret during the charging process tremendously counteract the effect of the charges on the front and reduce the output power. Eventually the theoretical and experimental results are very close when the net charge density is used instead of the surface charge density.

The large-size graphene-like porous carbon nanosheets (LGPCN) with controllable N-doped surface are successfully prepared by using a simple and effective integrated “self-template” and “designing” strategy through KOH activation. Biomass-sugarcane bagasse pith and chitosan are used as self-template carbon source and controlled nitrogen source, respectively. The relationship between structure of the LGPCN-X (X represents the activation temperature) and its electrochemical performance at different activation temperatures is explored in detail. The large-size multiscale wrinkled nanosheets architecture, high surface area, and appropriate controllable surface nitrogen doping state of the LGPCN-800 shows the best electrochemical performance in 6 M KOH. The largest specific electrode capacitance is about 339 F g −1 (at 0.25 A g −1 ), which still as high as 280 F g −1 at 100 A g −1 . The maximum energy density is about 11.77 Wh kg −1 at a power density of 34.11 W kg −1 . The LGPCN-800 also shows an excellent cycling stability with 97.9% capacitance retention after 10,000 cycles.

Fine particulate matter (PM 2.5 ) samples were collected simultaneously every hour in Beijing between April 2014 and April 2015 at five sites. Thirteen trace elements (TEs) in PM 2.5 were analyzed by online X-ray fluorescence (XRF). The annual average PM 2.5 concentrations ranged from 76.8 to 102.7 μg m −3 . TEs accounted for 5.9%–8.7% of the total PM 2.5 mass with Cl, S, K, and Si as the most dominant elements. Spearman correlation coefficients of PM 2.5 or TE concentrations between the background site and other sites showed that PM 2.5 and some element loadings were affected by regional and local sources, whereas Cr, Si, and Ni were attributed to substantial local emissions. Temporal variations of TEs in PM 2.5 were significant and provided information on source profiles. The PM 2.5 concentrations were highest in autumn and lowest in summer. Mn and Cr showed similar variation. Fe, Ca, Si, and Ti tended to show higher concentrations in spring, whereas concentrations of S peaked in summer. Concentrations of Cl, K, Pb, Zn, Cu, and Ni peaked in winter. PM 2.5 and TE median concentrations were higher on Saturdays than on weekdays. The diurnal pattern of PM 2.5 and TE median concentrations yielded similar bimodal patterns. Five dominant sources of PM 2.5 mass were identified via positive matrix factorization (PMF). These sources included the regional and local secondary aerosols, traffic, coal burning, soil dust, and metal processing. Air quality management strategies, including regional environmental coordination and collaboration, reduction in secondary aerosol precursors, restrictive vehicle emission standards, promotion of public transport, and adoption of clean energy, should be strictly implemented. High time-resolution measurements of TEs provided detailed source profiles, which can greatly improve precision in interpreting source apportionment calculations; the PMF analysis of online XRF data is a powerful tool for local air quality management.

The effects of high-Z dopant on the laser-driven ablative Richtmyer–Meshkov instability (RMI) are investigated by theoretical analysis and radiation hydrodynamics simulations. It is found that the oscillation amplitude of ablative RMI depends on the ablation velocity, the blow-off plasma velocity and the post-shock sound speed. Owing to enhancing the radiation at the plasma corona and increasing the radiation temperature at the ablation front, the high-Z dopant in plastic target can significantly increase the ablation velocity and the blow-off plasma velocity, leading to an increase in oscillation frequency and a reduction in oscillation amplitude of the ablative RMI. The high-Z dopant in plastic target is beneficial to reduce the seed of ablative Rayleigh–Taylor instability. These results are helpful for the design of direct drive inertial confinement fusion capsules.

We describe an ultra-stable, ultra-robust, straightforward and low-cost approach for the colorimetric detection of H2S with nanocrystalline cellulose (NCC) based on the reaction of H2S with lead acetate. The presence of NCC not only mediates the seed growth of a PbS/NCC complex, but also acts as a stabilizer protecting PbS from precipitation. This stable system is so robust that it can be used to quantitatively detect H2S even after two-year storage.

Sarcophaga peregrina is considered to be of great ecological, medical and forensic significance, and has unusual biological characteristics such as an ovoviviparous reproductive pattern and adaptation to feed on carrion. The availability of a high-quality genome will help to further reveal the mechanisms underlying these charcateristics. Here we present a de novo-assembled genome at chromosome scale for S. peregrina. The final assembled genome was 560.31 Mb with contig N50 of 3.84 Mb. Hi-C scaffolding reliably anchored six pseudochromosomes, accounting for 97.76% of the assembled genome. Moreover, 45.70% of repeat elements were identified in the genome. A total of 14,476 protein-coding genes were functionally annotated, accounting for 92.14% of all predicted genes. Phylogenetic analysis indicated that S. peregrina and S. bullata diverged ~ 7.14 million years ago. Comparative genomic analysis revealed expanded and positively selected genes related to biological features that aid in clarifying its ovoviviparous reproduction and carrion-feeding adaptations, such as lipid metabolism, olfactory receptor activity, antioxidant enzymes, proteolysis and serine-type endopeptidase activity. Protein-coding genes associated with ovoviparity, such as yolk proteins, transferrin and acid sphingomyelinase, were identified. This study provides a valuable genomic resource for S. peregrina, and sheds insight into further revealing the underlying molecular mechanisms of adaptive evolution.

Global energy interconnection (GEI) is of great significance to realize the worldwide optimal utilization of renewable energy, which is facing numerous challenges. In order to tackle underlying challenges and support decision making, the simulation of GEI evolution process makes sense. A dynamic GEI simulation method is proposed for the prediction of evolution process and the capture of critical challenges. The critical affecting factors of GEI evolution process, such as the international politics and economy, are analyzed. Then, the GEI evolution process is modeled as a differential kinetic equation that consists of the impacts of international politics and economy. Additionally, the improved Euler method is utilized to solve the dynamic model and the GEI evolution process is obtained. Finally, simulation results show the validity and effectiveness of proposed method.

Necrophagous fly species are commonly used as forensic tools to estimate the minimum postmortem interval (PMImin). Many researchers raised necrophagous flies under constant temperature regimes to collect their developmental data. However, in most forensic cases, the ambient temperature fluctuates. In order to investigate a forensically important fly developmental mode (the Isomegalen diagram, Isomorphen diagram and Thermal summation models) and make comparisons of the developmental rate between constant temperatures and fluctuating temperatures, we used Aldrichina grahami (Diptera: Calliphoridae) to investigate the life history parameters at eight constant temperatures ranging from 8 to 36 &deg, C. We also compared developmental rate of A. grahami in three groups of constant versus fluctuating temperatures: 8 &deg, C vs. 6&ndash, 12 &deg, C, 12 &deg, C vs. 10&ndash, 16 &deg, C, and 16 &deg, C vs. 14&ndash, 20 &deg, C. Our data showed that A. grahami is cold tolerant with a mean (&plusmn, SE) development threshold temperature (D0) of 3.41 &plusmn, 0.48 &deg, C and a thermal summation constant (K) of 8125.2 &plusmn, 288.4-degree hours. The three groups subjected to fluctuating temperatures took longer to develop compared to those developing in constant temperatures when simulated in a model. These results not only provide detailed developmental data for the use of A. grahami in the estimation of the PMI, but also indicate that ambient temperature fluctuation must be taken into consideration for the use of all necrophagous fly species.

Energy harvesters with higher power and direct-current (DC) output are of great significance for the energy supply of electronic devices. Here, we demonstrate rotary disk multi-phase freestanding-electret generators (MFEGs) with enhanced output power and low ripple output via a novel design. This novel design can enhance the output power by the reduction of generator capacitance and the improvement of the transferable charge density through positively utilizing the edge effect. The factors which both theoretical and experimental results show that the two- and three-phase FEGs have higher maximum output power than that of the conventional single-phase FEG (SFEG) and the two-phase FEG (TFEG) has the highest one. To further improve the output power, we optimize the structural parameters of TFEG and obtain 78.4% higher maximum output power than that of the optimal SFEG in experiment. Moreover, MFEGs connected to rectifier bridges obtain almost DC outputs. And since each phase of MFEGs is independent, the output of each phase can be utilized separately, for example, one as sensing signal and the other as energy output, providing a broad prospect for self-powered sensing.

Urban green spaces can improve residents’ health and well-being. However, international research shows that urban greening can produce gentrification effects. A dilemma for planners is determining whether the scale of greening or the characteristics of green spaces is driving gentrification. In this article, Canonical correlation analysis (CCA) and field investigations are used to assess the potential gentrification effects of a new public green space in the urban central area of Hangzhou, China. Hangzhou is one of China’s ‘garden cities’, but rapid urbanization and climate change are increasing urban heat-island impacts, requiring large-scale urban greening. The two-stage CCA not only confirms the green gentrification phenomenon within the study area but suggests that large green spaces appear to foster gentrification due to their functional benefits, favorable policy support, elaborate embellishments, and strict management and maintenance regimes. Appropriate policy responses may include using a ‘just green enough’ approach: whereby distributed smaller green spaces, with less stringent maintenance could resolve the green gentrification paradox.

Nanogenerators have shown their promising potential in energy harvesting and self-powered sensing. There are numerous working configurations and several output modes for nanogenerators. In this paper, a theoretical study is conducted analytically and numerically on electret-based nanogenerators as a dynamic motion sensor working in the contact-separation mode with resistive load. The analytical solution is derived as the asymptote for the output voltage across the load resistor under sinusoidal input movement. The effectiveness and the prerequisite condition of the deduced analytical solution is validated by numerical calculation. The influence of initial conditions on transient process is investigated. It is derived and demonstrated that certain amount of initial charges on electrodes will shorten or even eliminate the transient process. Making an analogy with a typical first-order resistor-capacitor high pass filter, the magnitude and cut-off frequency of the nanogenerator are extracted from the analytical solution. The impact on the output performance of parameters related to the device, the input motion and the measurement circuit are explored in detail. A design and optimization flow is proposed for the nanogenerator-based motion sensor, which will serve as a guidance and a powerful tool that can be referred to in practical applications.

VO2(B) is a promising cathode candidate for aqueous zinc ion batteries owing to its special tunnel lattice structure. However, the zinc storage mechanisms of VO2(B) are elusive over large voltage range, especially at the high potential. Via combined structure and composition characterizations such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy as well as electrochemical tests, it is demonstrated that VO2(B) goes through a conversion reaction when the potential approaching about 1.5 V during the first charging process. The obtained conversion product Zn3(OH)2V2O7·2H2O shows high zinc ion storage capacity of 330 mA h g−1 at 0.1 A g−1, fast zinc ion diffusion kinetics, and high rate performances (130 mA h g−1 at 10 A g−1). This work provides a novel strategy for the rational design of electrode materials with large voltage range, especially for aqueous multi-valence ion batteries.

Low yields of winter wheat are common throughout the Loess Plateau due to the region's erratic precipitation and the mismatch between the rainy season and the winter wheat growing season. In order to achieve sustainable high yields of winter wheat in this area, we set 6,000 kg hm−2 as our yield goal and investigated the effects of four types of management systems, including a conventional farmers’ management system and three integrated management systems, on winter wheat production over five consecutive years. The management practices varied in terms of seeding rates, nitrogen (N) application strategies, and application of manure or biochar. Our five-year study revealed that the average winter wheat yield under a manure integrated system (MIS) or a biochar integrated system (BIS) could achieve nearly 6,000 kg hm−2 while also enhancing water use efficiency (WUE) to 1.63–1.69 kg m−3. The high yields under MIS and BIS were mainly due to the large plant population that these systems permitted during the whole growing season, which was supported by favorable soil N levels (NO3−–N content) and sufficient water supply. The high WUE under both systems was mainly due to decreased loss of precipitation (i.e., increased storage in the soil) during early growth stages (from sowing time to regreening stage) and increased use of subsoil water (100–300 cm) during late growth stages (from regreening to harvest time) by the large root system. In addition, the annual evapotranspiration under MIS and BIS was much lower than the annual precipitation in this area. Therefore, MIS and BIS are likely to be useful integrated management systems enabling sustainable high yields of winter wheat in the Loess Plateau through the regulation of water use patterns in both spatial and temporal terms.

Contact-separation mode nanogenerator-based sensors (CS-NGSs) have attracted much attention by taking advantage of self-powering, high-sensitivity, simple structure, and low cost. To design a better CS-NGS for practical application, a systematic analysis of the sensor properties for CS-NGSs was implemented in this work. The sensor properties including frequency response, sensitivity, linearity, and distortion were analyzed for CS-NGSs with different output signals such as open-circuit voltage, short-circuit transferred charge, short-circuit current, and load voltage. The influence of the structure parameters and the working conditions on these properties were discussed too. Simulation experiments were conducted for CS-NGSs under three typical application scenarios, and the results indicate that the △QSC-type, the ISC-type, and the VL-type CS-NGSs have their own suitable application areas. The properties between the different output-type CS-NGSs are comprehensively compared. This work presents a systematic interpretation of the sensor properties of CS-NGSs and provides guidance for the design and optimization of CS-NGSs for specific applications.

A unique electrode architecture consisting of Ni3Se2 nanosheet-on-Ni3Se2-nanoforests grown on nickel foam was obtained by a simple one-step solvothermal method, which subsequently used as a free-standing electrode for supercapacitor. The Ni3Se2 exhibited a high capacity of up to 600 μAh cm−2 at 3 mA cm−2, excellent rate capability and cycling stability at high cycling rates. Impressively, the optimized hybrid supercapacitor containing Ni3Se2 cathode still released 94.4% of initial capacity for 505 μAh cm−2 after 6000 cycles at 20 mA cm−2. The results suggest that the Ni3Se2 nanoforests developed electrode has great potential for practical applications in hybrid supercapacitors.

The electrochemical behaviour and surface conductivity of niobium carbide modified-304 stainless steel (Nb-C 304 SS) bipolar plate in simulated cathode (0.5 M H 2 SO 4 + 2 ppm HF + 0.1 M methanol solution at 50 °C, bubbled with air) and varied anode (0.5 M H 2 SO 4 + 2 ppm HF + x M methanol (x = 1, 5, 10 and 20) solution at 50 °C) DMFC environments are systematically investigated. The results of potentiodynamic and potentiostatic polarisation tests show that corrosion resistance of 304 SS is greatly improved by the niobium carbide diffusion layer. Moreover, the Nb-C 304 SS shows an enhanced corrosion resistance in higher methanol content solution. According to the analyses of Mott–Schottky and X-ray photoelectron spectroscopy, although semi-conductive passive film forms on Nb-C 304 SS after potentiostatic polarisation in all the test solutions, the surface conductivity is still high. In addition, the thickness of passive film is thinner in the higher methanol content solution, which is beneficial for decreasing the interfacial contact resistance.

Nanocrystalline cellulose (NCC) is a kind of natural biopolymers with merits of large surface area, high specific strength and unique optical properties. This report shows that NCC can serve as the substrate, allowing glucose to reduce Tollen's reagent to produce silver nanoparticles (AgNPs) at room temperature. The generation of AgNPs is affected by the factors such as the concentrations of silver ions, NCC and glucose, as well as the different reaction temperatures. The AgNPs with NCC are applied for the development of a visual, quantitative, nonenzymatic and high-sensitive assay for glucose detection in serum. This assay is also used for monitoring the concentration change of glucose in medium during cell culture. For the antibacterial activity, the minimal inhibitory concentration (MIC) of the generated AgNPs with NCC is much lower than that of commercial AgNPs, attributed to the good dispersion of AgNPs with the presence of NCC. As NCC exhibits unique advantages including green, stable, inexpensive, and abundant, the NCC-based generation of AgNPs may find promising applications in clinical diagnosis, environmental monitoring, and the control of bacteria.

Copper nanoparticles (Cu NPs) spaced reduced graphene oxide (rGO) films are fabricated by integrating electrophoresis deposition (EPD) with thermal H2 annealing. The Cu NPs are formed through thermal aggregation and reduction of Cu(II) ions which are counter cations of GO. By tuning the annealing temperature from 400 to 850 °C, the mean diameter of the Cu NPs increases from 35 to 124 nm. Chemical characterizations reveal that the EPD technique may partially remove the O-containing groups of the GO film, while complete removal of the O-containing groups and effective repair of the graphene defects are achieved by thermal H2 treatment. With the implantation of Cu NPs, the resultant rGO/Cu NP films exhibit high porosity and amazing electric conductivities, enabling their direct use as lithium-ion battery (LIB) electrodes (vs. Li/Li+) without a general current collector, binder, and other additives. This novel LIB has a high charge/discharge capacity (>463 mA h g−1), an excellent reversibility, and a high coulombic efficiency (nearly 100%) for 300 cycles at a current density of 0.2 A g−1. It also exhibits good rate capacity: 849 mA h g−1@0.1 A g−1, 618 mA h g−1@0.2 A g−1, 516 mA h g−1@0.3 A g−1, and 470 mA h g−1@0.5 A g−1. Our new technique provides advanced design strategies for high performance LIBs and ultracapacitors, which might be used for mobile phone and electrical vehicles with unprecedented performances.