Changes in Microbial Composition During the Succession of Biological Soil Crusts in Alpine Hulun Buir Sandy Land, China.

Biological soil crusts (biocrusts) are considered "desert ecosystem engineers" because they play a vital role in the restoration and stability maintenance of deserts, including those cold sandy land ecosystems at high latitudes, which are especially understudied. Microorganisms participate in the formation and succession of biocrusts, contributing to soil properties' improvement and the stability of soil aggregates, and thus vegetation development. Accordingly, understanding the composition and successional characteristics of microorganisms is a prerequisite for analyzing the ecological functions of biocrusts and related applications. Here, the Hulun Buir Sandy Land region in northeastern China-lying at the highest latitude of any sandy land in the country-was selected for study. Through a field investigation and next-generation sequencing (Illumina MiSeq PE300 Platform), our goal was to assess the shifts in diversity and community composition of soil bacteria and fungi across different stages during the succession of biocrusts in this region, and to uncover the main factors involved in shaping their soil microbial community. The results revealed that the nutrient enrichment capacity of biocrusts for available nitrogen, total nitrogen, total phosphorus, total content of water-soluble salt, available potassium, soil organic matter, and available phosphorus was progressively enhanced by the succession of cyanobacterial crusts to lichen crusts and then to moss crusts. In tandem, soil bacterial diversity increased as biocrust succession proceeded but fungal diversity decreased. A total of 32 bacterial phyla and 11 fungal phyla were identified, these also known to occur in other desert ecosystems. Among those taxa, the relative abundance of Proteobacteria and Cyanobacteria significantly increased and decreased, respectively, along the cyanobacterial crust-lichen-moss crust successional gradient. However, for Actinobacteria, Chloroflexi, and Acidobacteria their changed relative abundance was significantly hump-shaped, increasing in the shift from cyanobacterial crust to lichen crust, and then decreasing as lichen crust shifted to moss crust. In this process, the improved soil properties effectively enhanced soil bacterial and fungal community composition. Altogether, these findings broaden our understanding about how soil microbial properties can change during the succession of biocrusts in high-latitude, cold sandy land ecosystems.

Biomimetic chiral hydrogen-bonded organic-inorganic frameworks.

Assembly ubiquitously occurs in nature and gives birth to numerous functional biomaterials and sophisticated organisms. In this work, chiral hydrogen-bonded organic-inorganic frameworks (HOIFs) are synthesized via biomimicking the self-assembly process from amino acids to proteins. Enjoying the homohelical configurations analogous to α-helix, the HOIFs exhibit remarkable chiroptical activity including the chiral fluorescence (glum = 1.7 × 10-3) that is untouched among the previously reported hydrogen-bonded frameworks. Benefitting from the dynamic feature of hydrogen bonding, HOIFs enable enantio-discrimination of chiral aliphatic substrates with imperceivable steric discrepancy based on fluorescent change. Moreover, the disassembled HOIFs after recognition applications are capable of being facilely regenerated and self-purified via aprotic solvent-induced reassembly, leading to at least three consecutive cycles without losing the enantioselectivity. The underlying mechanism of chirality bias is decoded by the experimental isothermal titration calorimetry together with theoretic simulation.

Differences of airborne and mural microorganisms in a 1,500-year-old Xu Xianxiu's Tomb, Taiyuan, China.

Background: Microbial colonization represents one of the main threats to the conservation of subterranean cultural heritage sites. Recently, the microbial colonization on murals in tombs has gradually attracted attention. Methods: In this study, a total of 33 samples, including 27 aerosol samples and 6 mural painting samples, were collected from different sites of Xu Xianxiu's Tomb and analyzed using culture-dependent methods. We compared the diversities of culturable bacteria and fungi isolated from the air and murals and explored the potential impacts of microorganisms on the biodeterioration of the murals. Results: Phylogenetic analyses revealed that the culturable bacteria belonged to Bacillus, Microbacterium, Lysobacter and Arthrobacter. And the most of fungal belonged to the Penicillium, Cladosporium and Aspergillus genera. The composition and structure of airborne bacteria and fungi outside the tomb were both significantly different from that inside the tomb. The variation trends of airborne bacterial and fungal concentrations at different sampling sites were remarkably similar. Bacillus frigoritolerans, Bacillus halotolerans, Bacillus safensis, Exiguobacterium mexicanum, Microbacterium trichothecenolyticum, and Micrococcus yunnanensis were bacterial species commonly isolated from both the mural and air environments. Fungal species commonly isolated from aerosol samples and mural painting samples were Alternaria alternata, Cladosporium cladosporioides, Penicillium brevicompactum, and Peyronellaea glomerata. The prediction of the ecological functions of the bacteria revealed that chemoheterotrophy or aerobic_chemoheterotrophy accounted for substantial relative proportions in all sample types. Conclusion: These results suggest that the aerosol circulation between the inside and outside environments of the tomb was weak and that the outside environment had yet to have an impact on the air microbial community inside the tomb. Selective colonization of microorganisms, which is mediated by interaction between microorganisms and special microenvironmental factors, is an important reason for the biodeterioration of murals.

Tuneable Anisotropic Plasmonics with Shape-Symmetric Conducting Polymer Nanoantennas.

A wide range of nanophotonic applications rely on polarization-dependent plasmonic resonances, which usually requires metallic nanostructures that have anisotropic shape. This work demonstrates polarization-dependent plasmonic resonances instead by breaking symmetry via material permittivity. The study shows that molecular alignment of a conducting polymer can lead to a material with polarization-dependent plasma frequency and corresponding in-plane hyperbolic permittivity region. This result is not expected based only on anisotropic charge mobility but implies that also the effective mass of the charge carriers becomes anisotropic upon polymer alignment. This unique feature is used to demonstrate circularly symmetric nanoantennas that provide different plasmonic resonances parallel and perpendicular to the alignment direction. The nanoantennas are further tuneable via the redox state of the polymer. Importantly, polymer alignment could blueshift the plasma wavelength and resonances by several hundreds of nanometers, forming a novel approach toward reaching the ultimate goal of redox-tunable conducting polymer nanoantennas for visible light.

Soil extracellular enzyme stoichiometry reflects microbial metabolic limitations in different desert types of northwestern China.

Soil extracellular enzyme activity (EEA) stoichiometry reflects the dynamic balance between microorganism metabolic demands for resources and nutrient availability. However, variations in metabolic limitations and their driving factors in arid desert areas with oligotrophic environments remain poorly understood. In this study, we investigated sites in different desert types in western China and measured the activities of two C-acquiring enzymes (ß-1,4-glucosidase and ß-D-cellobiohydrolase), two N-acquiring enzymes (ß-1,4-N-acetylglucosaminidase and L-leucine aminopeptidase), and one organic-P-acquiring enzyme (alkaline phosphatase) to quantify and compare the metabolic limitations of soil microorganisms based on their EEA stoichiometry. The ratios of log-transformed C-, N-, and P-acquiring enzyme activities for all deserts combined were 1:1.1:0.9, which is close to the hypothetical global mean EEA stoichiometry (1:1:1). We quantified the microbial nutrient limitation by means of vector analysis using the proportional EEAs, and found that microbial metabolism was co-limited by soil C and N. For different desert types, the microbial N limitation increased in the following order: gravel desert < sand desert < mud desert < salt desert. Overall, the study area's climate explained the largest proportion of the variation in the microbial limitation (17.9 %), followed by soil abiotic factors (6.6 %) and biological factors (5.1 %). Our results confirmed that the EEA stoichiometry method can be used in microbial resource ecology research in a range of desert types, and that the soil microorganisms maintained community-level nutrient element homeostasis by adjusting enzyme production to increase uptake of scarce nutrients even in extremely oligotrophic environments such as deserts.

All-Printed Flexible Hygro-Thermoelectric Paper Generator.

The conversion of ubiquitous hygrothermal resources into renewable energy offers significant potential for cable-free, self-powered systems that can operate worldwide without regard to climatic or geographic limitations. Here, an all-printed flexible hygro-thermoelectric paper generator is demonstrated that uses bifunctional mobile ions and electrons to make the moist-diffusion effect, the Soret effect, and the Seebeck effect work synergistically. In the ordinary hygrothermal settings, it generates an unconventional hygro-thermoelectric output pattern and shows almost a dozen-fold increase in positive hygro-thermopower of 26.70 mV K-1 and also another negative hygro-thermopower of -15.71 mV K-1 compared to pure thermopower. A single paper generator can produce a giant 680 mV displaying typical cyclic sinusoidal waveform characters with volt-sized amplitudes. The ion-electron conductive ink is easily printable and consists primarily of a Bi2 Te3 /PEDOT:PSS thermoelectric matrix modulated with a hygroscopic glycerol that releases ion charges for moist-diffusion effect and Soret effect, as well as electron charges for Seebeck effect. The emerged hygro-thermoelectric harvesting strategy from surrounding hygrothermal resources offers a revolutionary approach to the next generation of hybrid energy with cost-efficiency, flexibility, and sustainability, and also enables large-scale roll-to-roll production.

A Deep Learning Method of Human Identification from Radar Signal for Daily Sleep Health Monitoring.

Radar signal has been shown as a promising source for human identification. In daily home sleep-monitoring scenarios, large-scale motion features may not always be practical, and the heart motion or respiration data may not be as ideal as they are in a controlled laboratory setting. Human identification from radar sequences is still a challenging task. Furthermore, there is a need to address the open-set recognition problem for radar sequences, which has not been sufficiently studied. In this paper, we propose a deep learning-based approach for human identification using radar sequences captured during sleep in a daily home-monitoring setup. To enhance robustness, we preprocess the sequences to mitigate environmental interference before employing a deep convolution neural network for human identification. We introduce a Principal Component Space feature representation to detect unknown sequences. Our method is rigorously evaluated using both a public data set and a set of experimentally acquired radar sequences. We report a labeling accuracy of 98.2% and 96.8% on average for the two data sets, respectively, which outperforms the state-of-the-art techniques. Our method excels at accurately distinguishing unknown sequences from labeled ones, with nearly 100% detection of unknown samples and minimal misclassification of labeled samples as unknown.

Differential Influences of Wind-Blown Sand Burial on Bacterial and Fungal Communities Inhabiting Biological Soil Crusts in a Temperate Desert, China.

Biological soil crusts (BSCs) are an integration of external photoautotrophs and internal heterotrophic communities. Sand burial is a ubiquitous disturbance that affects the biodiversity and ecological function of BSCs, but little is known about the influence of sand burial on microbial communities in arid sandy deserts. Here, based on a long-term field experiment and utilizing high-throughput sequencing, we assessed the influence of sand burial on bacterial and fungal communities inhabiting two typical successional stages of BSCs (cyanobacterial crusts for early successional stage and mixed crusts for late successional stage) at the three-sand buried depth (0, 0.5, and 10 mm) in the Tengger Desert, Northern China. We found that the diversity, abundance, and composition of the bacterial and fungal communities were all altered by the sand burial treatment. Different indicator taxa were identified in unburied and buried (shallow and deep) BSCs. Changes in soil properties caused by sand burial have been suggested as a possible cause of changes in the bacterial and fungal community composition in BSCs.

Planting Cyperus esculentus augments soil microbial biomass and diversity, but not enzymatic activities.

The planting of Cyperus esculentus, a member of the grass family Cyperaceae which includes nut sedge weeds, is being increasingly promoted in northern China's semi-arid and arid regions. Yet the effects of planting C. esculentus upon soil quality and soil microbial characteristics of sandy land remain unclear. This study examined the short-term (1 year) impact of this grass species on soil microbial biomass indices, enzymatic activities, and microbiome characteristics in the Horqin Sandy Land area of China. The results show that planting C. esculentus could increase microbial biomass in the form of carbon (MBC), nitrogen (MBN), and phosphorus (MBP), but it negligibly influenced the enzymatic activities of soil ß-1,4-glucosidase (BG), cellobiohydrolase (CBH), leucine aminopeptidase (LAP), and ß-1,4-N-acetaminoglycosidase (NAG). Over 1 year, we found that planting C. esculentus significantly increased the soil bacterial richness and diversity of sandy land, yet also altered community composition of soil bacteria and eukaryotes in way that could promote their homogenization. In this respect, the relative abundances of Acidobacteria and Proteobacteria significantly decreased and increased, respectively; hence, they may be considered for use as important indicators of soil nutrient-rich conditions. Overall, the results could be explained by greater soil organic carbon (SOC) and total nitrogen (TN), mainly derived from cumulative plant litter input to soils, which then increased the sandy soil's C:N ratio. Future research should focus on exploring the long-term effects of planting C. esculentus on soil quality and soil microbial characteristics of sandy lands in China and abroad.

Study on the Influence of Vent Shape and Blockage Ratio on the Premixed Gas Explosion in the Chamber with a Small Aspect Ratio.

Given the current situation of deflagration caused by gas leakage for domestic use and the study of the single shape of the vent, the differential change law of vent parameters on the small aspect ratio of the chamber explosion flame evolution and explosion overpressure and other effects were experimentally investigated. Based on the theory of geometric similarity, the experimental platform of a small length-diameter ratio explosion chamber was designed and built, and the premixed gas explosion experiment was carried out by changing the shape (square and rectangle) and blockage ratio (0.1, 0.3, 0.5, 0.7, and 0.9). The explosion flame structure, flame front position, flame propagation speed, explosion pressure waveform, overpressure peak value, and so on were tested and analyzed. The results showed that the blockage ratio had the most significant effect on flame propagation and explosion flame evolution. With the increase of blockage ratio, the stretching degree of the flame became more and more obvious, the flame front became sharper and sharper, and the sharp flame changed from the lower part to the upper part. The position of the flame front increased rapidly, and the steepness and peak value of explosion overpressure became larger. The oscillation of the flame propagation velocity was more violent after the turn, and the speed of propagation to the outside of the chamber gradually accelerated. In the same blockage ratio, there was a difference in the time point at which the flame propagation velocity turned under the rectangular and square shape of the vent. In blockage ratios of 0.1, 0.3, 0.5, and 0.9, the peak overpressure reduction under the shape of the blast square relative to the rectangle was 41.3, 47.9, 1.03, and 27.6%. This indicated that the explosion relief effect of the square was better than that of a rectangle. The research results can provide a reference and basis for the reasonable deployment of explosion venting and explosion decompression work.

Differences and spatial variations of plant leaf calorific value in deserts of the Hexi Corridor, Northwestern China.

The leaf calorific value (LCV) is an important trait that indicates how efficiently a plant utilizes natural resources to capture energy. However, little is known about the LCV characteristics of plants in arid and hyper-arid environments. To investigate the spatial patterns and variations in LCV of desert plants and their possible causes, we collected 343 leaf samples of 52 species along a 1000-km transect in the desert area of northwestern China. We analyzed the gross calorific value (GCV), ash-free calorific value (AFCV), carbon content (CC), nitrogen content (NC), and ash content (AC) of the leaves. The mean leaf GCV and AC were 16.2 kJ g-1 (range from 8.9 to 20.1 kJ g-1), and 189.8 mg g-1 (range from 61.5 to 495.1 mg g-1) respectively, which differ significantly from the values for plants growing in more humid areas of China. Succulence was the dominant trait that drove the differences in leaf GCV and AFCV among plant functional groups. Succulent plants had significantly lower leaf GCV and AFCV, and significantly higher AC, than non-succulent plants, indicating that the investment of energy for succulent plants in response to drought stress may be lower than that for non-succulent plants. Among the biological factors that affected LCV, the CC and AC were the main determinants of leaf GCV, whereas CC and NC were the main determinants of leaf AFCV. Drought stress is an environmental constraint that has a direct negative effect on both leaf GCV and AFCV, but its contribution may be weaker than phylogenetic effects. Our results suggest that LCV is a useful leaf trait that can be used to evaluate plant-environment interactions from an energy perspective.

Variations in seasonal and inter-annual carbon fluxes in a semi-arid sandy maize cropland ecosystem in China's Horqin Sandy Land.

Sandy cropland ecosystems are major terrestrial ecosystems in semi-arid regions of northern China's Horqin Sandy Land, where they play an important role in the regional carbon balance. Continuous observation of the CO2 flux was conducted from 2014 to 2018 using the eddy covariance technique in a sandy maize cropland ecosystem in the Horqin Sandy Land. We analyzed carbon fluxes (the net ecosystem exchange (NEE) of CO2, ecosystem respiration (Reco), and the gross primary productivity (GPP) and their responses to environmental factors at different temporal scales using Random Forest models and correlation analysis. We found that the sandy cropland was a carbon sink, with an annual mean NEE of -124.4 g C m-2 yr-1. However, after accounting for carbon exports and imports, the cropland became a net carbon source, with net biome production ranging from -501.1 to -266.7 g C m-2 yr-1. At a daily scale, the Random Forest algorithm revealed that photosynthetic photon flux density, soil temperature, and soil moisture were the main drivers for variation of GPP, Reco, and NEE at different integration periods. At a monthly scale, GPP and Reco increased with increasing leaf area index (LAI), so the maize ecosystem's carbon sequestration capacity increased with increasing LAI. At an annual scale, water availability (precipitation and irrigation) played a dominant role in explaining inter-annual variability of GPP and Reco. Affected by climate (e.g., precipitation) and field management (e.g., cultivation, irrigation), carbon fluxes differed greatly between years in the maize system.

Variation in Soil Microbial Communities Along an Elevational Gradient in Alpine Meadows of the Qilian Mountains, China.

Bacterial, archaeal, and eukaryota diversity in mountainous areas varies along elevational gradients, but details remain unclear. Here, we use a next-generation sequencing method based on 16S/18S rRNA to reveal the soil microbial diversity and community compositions of alpine meadow ecosystems along an elevation span of nearly 2,000 m (1,936-3,896 m) in China's Qilian Mountains. Both bacterial and eukaryota diversity increased linearly with increasing elevation, whereas archaeal diversity increased, but not significantly. The diversity patterns of several phyla in the bacterial, archaeal, and eukaryota communities were consistent with the overall elevational trend, but some phyla did not follow this pattern. The soil microbial community compositions were shaped by the coupled effects of regional climate and local soil properties. Intradomain links were more important than interdomain links in the microbial network of the alpine meadows, and these links were mostly positive. The bacteria formed more connections than either archaea or eukaryota, but archaea may be more important than bacteria in building the soil microbial co-occurrence network in this region. Our results provide new visions on the formation and maintenance of soil microbial diversity along an elevational gradient and have implications for microbial responses to climate change in alpine ecosystems.

Fully Controllable Structural Phase Transition in Thermomechanical Molecular Crystals with a Very Small Thermal Hysteresis.

The construction of a practical crystalline molecular machine faces two challenges: to realize a collective molecular movement, and to amplify this movement into a precisely controlled mechanical response in real time and space. Thermosalient single crystals display cooperative molecular movements that are converted to strong macroscopic mechanical responses or shape deformations during temperature-induced structural phase transitions. However, these collective molecular movements are hard to control once initiated, and often feature thermal hystereses that are larger than 10 °C, which greatly hamper their practical applications. Here, it is demonstrated that the phase boundaries of the thermomechanical molecular crystal based on a fluorenone derivative 4-DBpFO can be used to finely control its structural phase transition. When this phase transition is triggered at two opposite crystal faces, it is accompanied by two parallel phase boundaries that can be temperature controlled to move forward, backward, or to halt, benefitting from the stored elastic energy between the parallel boundaries. Moreover, the thermal hysteresis is greatly decreased to 2-3 °C, which allows for circular heating/cooling cycles that can produce a continuous work output.

Effects of Nitrogen Addition and Reproductive Effort on Nutrient Resorption of a Sand-Fixing Shrub.

Caragana microphylla is a sand-fixing leguminous shrub with strong resistance to drought, cold, and low soil fertility. As a result, it plays an essential role in combating desertification in northern China, but little is known about its nutrient budget. Nutrient resorption is a key process in plant nutrient conservation and has marked ecological implications for plant fitness and ecosystem nutrient cycling. We studied the effects of both nitrogen (N) addition and reproductive effort on leaf N resorption of C. microphylla in a temperate semi-arid sandy land in China. The results showed that sprouting of the early leaves from over-wintered buds employs a strategy for slow returns on nutrient investment with smaller specific leaf area (SLA) and higher N resorption efficiency, whereas the late leaves, which sprout from current-year buds, employ a strategy for quick returns on nutrient investment with higher SLA and lower N resorption efficiency. N addition significantly increased the N resorption efficiency from early leaves while exerting no impact on late leaves, suggesting that the increased N recovery from early leaves is done to sustain the high N demands of late leaves. Reproductive effort did not affect the N resorption from early or late leaves due to the temporal separation between fruit production and leaf senescence. Taken together, our results demonstrate that C. microphylla has evolved different investment strategies for leaf N in early and late leaves to conserve nutrients and facilitate its growth in desertified environments.

Robust thermoelastic microactuator based on an organic molecular crystal.

Mechanically responsive molecular crystals that reversibly change shape triggered by external stimuli are invaluable for the design of actuators for soft robotics, artificial muscles and microfluidic devices. However, their strong deformations usually lead to their destruction. We report a fluorenone derivative (4-DBpFO) showing a strong shear deformation upon heating due to a structural phase transition which is reproducible after more than hundred heating/cooling cycles. Molecular dynamic simulations show that the transition occurs through a nucleation-and-growth mechanism, triggered by thermally induced rotations of the phenyl rings, leading to a rearrangement of the molecular configuration. The applicability as actuator is demonstrated by displacing a micron-sized glass bead over a large distance, delivering a kinetic energy of more than 65 pJ, corresponding to a work density of 270 J kg-1. This material can serve as a prototype structure to direct the development of new types of robust molecular actuators.

Study on the long-term curative effect of repeat percutaneous balloon mitral valvuloplasty in patients with mitral restenosis.

To study the long-term curative effect of repeat percutaneous balloon mitral valvuloplasty (PBMV) in patients with mitral restenosis.In our study, mitral restenosis developed in 39 patients after PBMV. Repeat PBMV was performed according to the improved Inoue method. All patients were followed up.Of 39 patients, 36 were successfully treated with repeat PBMV (achievement ratio, 92.3%). Immediately after repeat PBMV, clinical symptoms and left atrial mean pressure (LAP), pulmonary artery systolic pressure (PASP), mitral valve gradient (MVG), and mitral valve orifice area (MVA) improved significantly (24.50 ±â€Š6.54 mmHg vs 9.66 ±â€Š4.21 mmHg for LAP, 1.05 ±â€Š0.19 cm vs 2.23 ±â€Š0.22 cm for MVA, 17.03 ±â€Š4.52 mmHg vs 7.79 ±â€Š4.07 mmHg for MVG, 58.12 ±â€Š12.68 mmHg vs 31.45 ±â€Š10.02 mmHg for PASP; P <.05). Meanwhile, left atrial end-diastolic dimension (LAD) was altered slightly (4.71 ±â€Š0.75 vs 4.07 ±â€Š0.69, P >.05). The 36 patients were followed up for 69 ±â€Š23 (12-146) months. After long-term follow-up immediately after repeat PBMV, the results did not show a significant change (2.23 ±â€Š-0.22 cm vs 2.02 ±â€Š-0.21 cm for MVA, 7.79 ±â€Š-4.07 mmHg vs 9.15 ±â€Š-4.11 mmHg for MVG; P >.05) and were approximated to those shortly after repeat PBMV (2.23 ±â€Š0.22 cm vs 2.02 ±â€Š0.21 cm for MVA, 7.79 ±â€Š4.07 mmHg vs 9.15 ±â€Š4.11 mmHg for MVG; P > 0.05). LAD did not change significantly (4.13 ±â€Š0.71 cm vs. 4.07 ±â€Š0.69 cm; P >.05). The long-term follow-up results showed that cardiac function and quality of life were significantly improved in most patients.It would be safe for patients with mitral restenosis to undergo repeat PBMV. Appropriate cases should be selected, and treatment should be performed cautiously. Short- and long-term curative effects would be satisfactory. We suggested that repeat PBMV be the first choice for patients with mitral restenosis after first PBMV.

Correction: The microbial community characteristics of ancient painted sculptures in Maijishan Grottoes, China.

[This corrects the article DOI: 10.1371/journal.pone.0179718.].

The microbial community characteristics of ancient painted sculptures in Maijishan Grottoes, China.

In this study, a culture-independent Illumina MiSeq sequencing strategy was applied to investigate the microbial communities colonizing the ancient painted sculptures of the Maijishan Grottoes, a famous World Cultural Heritage site listed by UNESCO in China. Four mixed samples were collected from Cave 4-4 of the Maijishan Grottoes, the so-called Upper Seven Buddha Pavilion, which was built during the Northern Zhou Dynasty (557-581AD). The 16/18S rRNA gene-based sequences revealed a rich bacterial diversity and a relatively low fungal abundance, including the bacterial groups Actinobacteria, Acidobacteria, Bacteroidetes, Cyanobacteria, Chloroflexi, Firmicutes, Proteobacteria and Verrucomicrobia and the fungal groups Ascomycota, Basidiomycota and Chytridiomycota. Among them, the bacteria genera of Pseudonocardia and Rubrobacter and unclassified fungi in the order of Capnodiales were dominant. The relative abundance of Pseudonocardia in the painted layer samples was higher than that in the dust sample, while Cyanobacteria dominated in the dust sample. Many of them have been discovered at other cultural heritage sites and associated with the biodeterioration of cultural relics. The presence and activity of these pioneering microorganisms may lead to an unexpected deterioration of the painted sculptures that are preserved in this heritage site. Thus, proper management strategies and potential risk monitoring should be used in the Maijishan Grottoes to improve the conservation of these precious painted sculptures.

Facile and Reliable in Situ Polymerization of Poly(Ethyl Cyanoacrylate)-Based Polymer Electrolytes toward Flexible Lithium Batteries.

Polycyanoacrylate is a very promising matrix for polymer electrolyte, which possesses advantages of strong binding and high electrochemical stability owing to the functional nitrile groups. Herein, a facile and reliable in situ polymerization strategy of poly(ethyl cyanoacrylate) (PECA) based gel polymer electrolytes (GPE) via a high efficient anionic polymerization was introduced consisting of PECA and 4 M LiClO4 in carbonate solvents. The in situ polymerized PECA gel polymer electrolyte achieved an excellent ionic conductivity (2.7 × 10-3 S cm-1) at room temperature, and exhibited a considerable electrochemical stability window up to 4.8 V vs Li/Li+. The LiFePO4/PECA-GPE/Li and LiNi1.5Mn0.5O4/PECA-GPE/Li batteries using this in-situ-polymerized GPE delivered stable charge/discharge profiles, considerable rate capability, and excellent cycling performance. These results demonstrated this reliable in situ polymerization process is a very promising strategy to prepare high performance polymer electrolytes for flexible thin-film batteries, micropower lithium batteries, and deformable lithium batteries for special purpose.