An integrated electronic skin with biaxial sensitivity from a layered biphasic liquid metal/polymer film.

Research on electronic skin (e-skin) is dedicated to simulating natural skin for the perception of external mechanical stimuli. Currently, e-skin is ineffective in analyzing a single stimulus from different directions. This work successfully fabricates an integrated electronic skin (IES) with biaxial sensing capability through the combination of a biphasic liquid metal and porous foam. Remarkably different from traditional e-skin, the IES can analyze the type, strength, and area of an external mechanical stimulus from vertical and horizontal dimensions with a dual response (capacitive and resistive change, respectively). As a multifunctional sensor, the IES simultaneously responds to compression via capacitive change and tension via resistive change. Furthermore, 1000 cyclic compressions were conducted to confirm the electrical stability of the IES. Very subtle stimuli (e.g. thawing ice and touch) can be detected by the IES via biaxial detection. This work provides a new protocol for the development of future intelligent flexible electronics.

Ultrahigh Heat/Fire-Resistant, Mechanically Robust, and Closed-Loop Chemical Recyclable Polycarbonate Enabled by Facile Bond Dissociation Energy Modulation.

Plastics serve as an essential foundation in contemporary society. Nevertheless, meeting the rigorous performance demands in advanced applications and addressing their end-of-life disposal are two critical challenges that persist. Here, an innovative and facile method is introduced for the design and scalable production of polycarbonate, a key engineering plastic, simultaneously achieving high performance and closed-loop chemical recyclability. The bisphenol framework of polycarbonate is strategically adjusted from the low-bond-dissociation-energy bisphenol A to high-bond-dissociation-energy 4,4'-dihydroxydiphenyl, in combination with the incorporation of polysiloxane segments. As expected, the enhanced bond dissociation energy endows the polycarbonate with an extremely high glow-wire flammability index surpassing 1025 °C, a 0.8 mm UL-94 V-0 rating, a high LOI value of 39.2%, and more than 50% reduction of heat and smoke release. Furthermore, the π-π stacking interactions within biphenyl structures resulted in a significant enhancement of mechanical strength by as more as 37.7%, and also played a positive role in achieving a lower dielectric constant. Significantly, the copolymer exhibited outstanding closed-loop chemical recyclability, allowing for facile depolymerization into bisphenol monomers and the repolymerized copolymer retains its high heat and fire resistance. This work provides a novel insight in the design of high-performance and closed-loop chemical recyclable polymeric materials.

Multifunctional, Degradable Wearable Sensors Prepared with an Initiator and Crosslinker-Free Method.

The present zwitterionic hydrogel-based wearable sensor exhibits various limitations, such as limited degradation capacity, unavoidable toxicity resulting from initiators, and poor mechanical properties that cannot satisfy practical demands. Herein, we present an initiator and crosslinker-free approach to prepare polyethylene glycol (PEG)@poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl) (PSBMA) interpenetrating polymer network (IPN) hydrogels that are self-polymerized via sunlight-induced and non-covalent crosslinking through electrostatic interaction and hydrogen bonding among polymer chains. The PEG@PSBMA IPN hydrogel possesses tissue-like softness, superior stretchability (∼2344.6% elongation), enhanced fracture strength (∼39.5 kPa), excellent biocompatibility, antibacterial property, reliable adhesion, and ionic conductivity. Furthermore, the sensor based on the IPN hydrogel demonstrates good sensitivity and cyclic stability, enabling effective real-time monitoring of human body activities. Moreover, it is worth noting that the excellent degradability in the saline solution within 8 h makes the prepared hydrogel-based wearable sensor free from the electronic device contamination. We believe that the proposed strategy for preparing physical zwitterionic hydrogels will pave the way for fabricating eco-friendly wearable devices.

Ultrasensitive Soft Sensor from Anisotropic Conductive Biphasic Liquid Metal-Polymer Gels.

Subtle vibrations, such as sound and ambient noises, are common mechanical waves that can transmit energy and signals for modern technologies such as robotics and health management devices. However, soft electronics cannot accurately distinguish ultrasmall vibrations owing to their extremely small pressure, complex vibration waveforms, and high noise susceptibility. This study successfully recognizes signals from subtle vibrations using a highly flexible anisotropic conductive gel (ACG) based on biphasic liquid metals. The relationships between the anisotropic structure, subtle vibrations, and electrical performance are investigated using rheological-electrical experiments. The refined anisotropic design successfully realized low-cost flexible electronics with ultrahigh sensitivity (Gauge Factor: 12787), extremely low detection limit (strain: 0.01%), and excellent frequency recognition accuracy (>99%), significantly surpassing those of current flexible sensors. The ultrasensitive flexible electronics in this study are beneficial for diverse advanced technologies such as acoustic engineering, wearable electronics, and intelligent robotics.

Dynamic changes in soil organic carbon induced by long-term compost application under a wheat-maize double cropping system in North China.

Soil organic carbon (SOC) plays a vital role in improving soil quality and alleviating global warming. Understanding the dynamic changes in SOC is crucial for its accumulation induced by compost application in agroecosystem. In this study, soil samples were collected from three treatments: high-rate bio-compost (BioMh), low-rate bio-compost (BioMl), and control (CK, no fertilization) during 2002-2020 in a wheat-maize double cropping system in North China. The soils were separated into three functional fractions, i.e., coarse particle organic matter (cPOM, >250 µm), microaggregates (µAgg, 53-250 µm) and mineral-associated organic matter (MAOM, < 53 µm), and the associated SOC contents were determined. During 1993-2002, SOC contents in bulk soil significantly increased with the duration in the BioMh and BioMl plots. However, there was no significant correlation between SOC content and duration during 2002-2020. These results suggested that compost application positively improved SOC sequestration, while the duration of SOC sequestration (i.e., the longevity of increased SOC with time) under compost inputs maintained only 9 years. Moreover, there was a significant increase in mean annual SOC contents in bulk soil with compost application rate during 2002-2020, indicating that carbon saturation did not occur. Additionally, the SOC contents in the cPOM fraction increased with time (p < 0.01), but the corresponding µAgg and MAOM associated SOC was insignificant (p > 0.05). The MAOM fraction exhibited no additional carbon accumulation with expanding compost application, confirming a hierarchical carbon saturation in these fractions. We concluded that soils under wheat-maize double cropping system in North China have greater potential to sequester C through additional compost inputs, despite showing hierarchical saturation behavior in the non-protected coarse particulate fraction.

Examination of the negative correlation between leaf δ15N and the N:P ratio across a northeast-southwest transect in China.

Nitrogen (N) and phosphorus (P) are two crucial limiting mineral elements for terrestrial plants. Although the leaf N:P ratio is extensively used to indicate plant nutrient limitations, the critical N:P ratios cannot be universally applied. Some investigations have suggested that leaf nitrogen isotopes (δ15N) can provide another proxy for nutrient limitations along with the N:P ratio, but the negative relationships between N:P and δ15N were mainly limited to fertilization experiments. It will obviously benefit the study of the nature of nutrient limitations if the relationship could be explained more generally. We analyzed leaf δ15N, N, and P contents across a northeast-southwest transect in China. Leaf δ15N was weakly negatively correlated with leaf N:P ratios for all plants, while there was no correlation between them for various plant groups, including different growth forms, genera, and species across the entire N:P range. This suggests that the use of leaf δ15N in indicating the shift of nutrient limitations across the whole N:P range still requires more validated field investigations. Notably, negative relationships between δ15N and N:P hold for plants with N:P ratios between 10 and 20 but not for plants with N:P ratios lower than 10 or higher than 20. That is, changes in leaf δ15N along with the N:P ratio of plants that are co-limited by N and P can exhibit variations in plant nutrient limitations, whereas plants that are strictly limited by N and P cannot. Moreover, these relationships are not altered by vegetation type, soil type, MAP, or MAT, indicating that the use of leaf δ15N in reflecting shifts in nutrient limitations, depending on the plant nutrient limitation range, is general. We examined the relationships between leaf δ15N and the N:P ratio across an extensive transect, providing references for the widespread use of leaf δ15N in reflecting shifts in nutrient limitation.

Addressing the Relationship between Leaf Nitrogen and Carbon Isotope Discrimination from the Three Levels of Community, Population and Individual.

The carbon, nitrogen and water cycles of terrestrial ecosystems are important biogeochemical cycles. Addressing the relationship of leaf nitrogen (N) and carbon isotope discrimination (Δ) will enhance the understanding of the links between these three cycles in plant leaves because Δ can reflect time-integrated leaf-level water-use efficiency (WUE) over the period when the leaf material is produced. Previous studies have paid considerable attention to the relationship. However, these studies have not effectively eliminated the interference of environmental factors, inter-species, and inter-individual differences in this relationship, so new research is necessary. To minimize these interferences, the present work explored the relationship at the three levels of community, population, and plant individual. Three patterns of positive, negative and no relationship were observed across communities, populations, and individuals, which is dependent on environmental conditions, species, and plant individuals. The results strongly suggested that there is no general pattern for the relationship between leaf N and Δ. Furthermore, the results indicated that there is often no coupling between leaf-level long-term WUE and leaf N in the metabolic process of carbon, N and water in leaves. The main reason for the lack of this relationship is that most plants do not invest large amounts of nitrogen into photosynthesis. In addition, the present study also observed that, for most plant species, leaf N was not related to photosynthetic rate, and that variations in photosynthetic rates are mainly driven by stomatal conductance.

Effects of Geographical and Climatic Factors on the Intrinsic Water Use Efficiency of Tropical Plants: Evidence from Leaf 13C.

Understanding the water use efficiency (WUE) and adaptation strategies of plants in high-temperature and rainy areas is essential under global climate change. The leaf carbon content (LCC) and intrinsic WUE of 424 plant samples (from 312 plant species) on Hainan Island were measured to examine their relationship with geographical and climatic factors in herbs, trees, vines and ferns. The LCC ranged from 306.30 to 559.20 mg g-1, with an average of 418.85 mg g-1, and decreased with increasing mean annual temperature (MAT). The range of intrinsic WUE was 8.61 to 123.39 µmol mol-1 with an average value of 60.66 µmol mol-1. The intrinsic WUE decreased with increasing altitude and relative humidity (RH) and wind speed (WS), but increased with increasing latitude, MAT and rainy season temperature (RST), indicating that geographical and climatic factors affect the intrinsic WUE. Stepwise regression suggested that in tropical regions with high temperature and humidity, the change in plant intrinsic WUE was mainly driven by WS. In addition, the main factors affecting the intrinsic WUE of different plant functional types of plants are unique, implying that plants of different plant functional types have distinctive adaptive strategies to environmental change. The present study may provide an insight in water management in tropical rainforest.

Organic carbon sequestration in Chinese croplands under compost application and its contribution to carbon neutrality.

Achieving the carbon neutrality in China has great impact on alleviating global warming. Compost application, an important measure to promote soil organic carbon (SOC) sequestration, has been practiced in China since 2015. However, it is still unclear how much carbon can be fixed by cropland soil under compost application in the whole China. China has pledged to strive for the goal of carbon neutrality by 2060, which brought two issues: whether compost application can consistently promote SOC sequestration until 2060, and how much contribution it can make to the carbon neutrality. In the present study, we analyzed the results from 93 literatures to determine the SOC sequestration under compost application in the different agricultural divisions of China. Results showed that there were regional differences in the effect of compost application on SOC sequestration. The annual SOC sequestration in Northern China (NC) and Gansu + Xinjiang (GX) was significantly high than other regions. In addition, the annual SOC sequestration was negatively related to the duration of the experiment, while the accumulative SOC sequestration during the experimental period increased with the increase of the duration. According to our results, the total SOC sequestration in topsoil of Chinese cropland was 85 Tg C year-1 under compost application, which will make a 4.4% contribution to carbon neutrality during 2021-2060. In conclusion, cropland soil in China can still sequester carbon for more than 35 years under compost application. Thus, abidingly promoting compost application in China is crucial to accomplishing the carbon neutrality goal.

Adverse childhood experiences, recent negative life events, and non-suicidal self-injury among Chinese college students: the protective role of self-efficacy.

BACKGROUND: Non-suicidal self-injury (NSSI) is a severe health problem closely related to adverse childhood experiences (ACEs). However, the underlying mechanisms by which ACEs may affect NSSI are largely unknown. Self-efficacy (NSSI-SE) and recent negative life events (RNLEs) may play important roles in this relationship. This study aimed to clarify the relationship between ACEs and NSSI among college students by examining the role of self-efficacy (NSSI-SE) and RNLEs in this process. METHOD: Relevant self-report questionnaires were used to evaluate ACEs, RNLEs, NSSI-SE, and NSSI. A questionnaire of 1036 Chinese undergraduates (Mage = 19.65, 28.9% males, 71.1% females) was collected in a cross-sectional manner. The associations between ACEs, RNLEs, NSSI-SE and NSSI were assessed using Pearson correlation analyses. Then, hierarchical multiple linear regressions were used to analyze the effects of ACEs and RNLEs on NSSI, as well as the protective effect of NSSI-SE on the above relations. RESULTS: NSSI was associated with both ACEs and RNLEs. ACEs and RNLEs could directly increase the risks of participating in NSSI, and the effects of ACEs and RNLEs on NSSI were independent without an interactive effect. NSSI-SE buffered the relationship between ACEs and NSSI, as well as between RNLEs and NSSI. Compared to individuals with a low level of NSSI-SE, ACEs and RNLEs were not significantly associated with NSSI in persons with a high level of NSSI-SE. CONCLUSION: NSSI-SE may buffer the effect of ACEs and RNLEs on NSSI, indicating that future interventions can be enhanced by targeting NSSI-SE among college students with ACEs or RNLEs to prevent their engagement in NSSI.

Deep Realistic Facial Editing via Label-restricted Mask Disentanglement.

With the rapid development of GAN (generative adversarial network), recent years have witnessed an increasing number of tasks on reference-guided facial attributes transfer. Most state-of-the-art methods consist of facial information extraction, latent space disentanglement, and target attribute manipulation. However, they either adopt reference-guided translation methods for manipulation or monolithic modules for diverse attribute exchange, which cannot accurately disentangle the exact facial attributes with specific styles from the reference image. In this paper, we propose a deep realistic facial editing method (termed LMGAN) based on target region focusing and dual label constraint. The proposed method, manipulating target attributes by latent space exchange, consists of subnetworks for every individual attribute. Each subnetwork exerts label-restrictions on both the target attributes exchanging stage and the training process aimed at optimizing generative quality and reference-style correlation. Our method performs greatly on disentangled representation and transferring the target attribute's style accurately. A global discriminator is introduced to combine the generated editing regional image with other nonediting areas of the source image. Both qualitative and quantitative results on the CelebA dataset verify the ability of the proposed LMGAN.

Changes in precipitation and atmospheric N deposition affect the correlation between N, P and K but not the coupling of water-element in Haloxylon ammodendron.

Global changes in precipitation and atmospheric N deposition affect the geochemical cycle of the element and its hydrological cycle in the ecosystem. It may also affect the relationship between plant water use efficiency (WUE) and nutrients, as well as the relationship between plant nutrients. Desert ecosystems are vulnerable to global changes. Haloxylon ammodendron is the dominant species in the Asian desert. Revealing the variations in these relationships in H. ammodendron with precipitation and N deposition will enhance our understanding of the responses of plants to global change in terms of trade-off strategies of nutrient absorption, water and element geochemical cycles in desert ecosystems. Thus, we conducted field experiments with different amounts of water and N. This study showed that WUE of H. ammodendron was not correlated with nitrogen content (N), phosphorus content (P), and potassium content (K) when water and N supply were varied (p > 0.05 for WUE vs. N, P, and K), suggesting lack of coupling between water use and nutrient economics. This result was associated with the lack of correlation between plant nutrients and gas exchang in H. ammodendron. However, water addition, N addition and the interaction between both of them all played a role in the correlation between plant N, P and K owing to their different responses to water and N supplies. This indicates that global changes in precipitation and N deposition will affect N, P and K geochemical cycles in the Asian deserts dominated by H. ammodendron, and drive changes in the relationships between plant nutrients, resulting in changes in the trade-off strategy of plant absorption of N, P, and K.

Biomass Shape Memory Elastomers with Rapid Self-Healing Properties and High Recyclability.

Biomass bifunctional polyamide elastomers (BbPEs) were successfully prepared from dimer acid (DA), trimer acid (TA), and triethylenetetramine with shape memory and self-healing abilities. In the composition structure of BbPEs, vast hydrogen bonds formed among the amide bonds of different segments endowed the BbPEs with self-healing ability. At room temperature, the mechanical properties of BbPEs can be restored to 49% of the original condition after healing for 2 h. In addition, the physical and chemical cross-linking endowed the BbPE with preferable mechanical and shape memory properties. The tensile strength of the material is 4.4 ± 0.1 MPa, and the elongation at break reaches 1500 ± 2%. Under the recovery temperature of 60 °C, the shape memory recovery rate of 5 min can reach 95%. The recovery efficiency is 88.9%. This material can be utilized for many practical applications, such as intelligent electronic devices, bionic materials, and so on.

Prospective Interpersonal and Intrapersonal Predictors of Initiation and Cessation of Non-Suicidal Self-Injury among Chinese Adolescents.

(1) Purpose: Non-suicidal self-injury (NSSI) possibly emerges as well as remits in adolescence. To explore the development and transition of NSSI, this study examined the association between a wide range of interpersonal and intrapersonal predictors of NSSI initiation and cessation. (2) Methods: Chinese adolescents (N = 913) completed self-reported surveys at baseline and at a six-month follow-up. The sample included 625 adolescents who reported no NSSI and 288 adolescents who reported engagement in NSSI at baseline. (3) Results: Among the adolescents without NSSI at baseline, 24.3% engaged in NSSI at follow-up (NSSI initiation group). Among the adolescents with NSSI at baseline, 33.3% reported no NSSI at follow-up (NSSI cessation group). Loneliness, beliefs about adversity, problem behavior, and prosocial behavior were the significant factors in predicting subsequent NSSI initiation. None of the potential predicting factors were associated with subsequent NSSI cessation. (4) Conclusions: These results indicate the importance of intrapersonal factors in Chinese culture, which could be used to identify at-risk adolescents and to design interventions.

Clarifying the influence of temperature on variances in plant metallic nutrients through minimizing the effect of precipitation.

Understanding the responses of plant nutrients to climate warming is important in the research of global change. However, the responses of plant metallic nutrients to climate warming have been rarely addressed. Furthermore, in previous field investigations, the influence of temperature on plant metallic nutrients has been not effectively separated from that of precipitation; hence, there exists some uncertainties in the relationships between plant metallic nutrients and temperature. To minimize the effect of precipitation, this study collected plant samples over broad geographical scale along the 400 mm isohyet in China with a temperature span of 14.8 °C. The temperature effects on variations in leaf potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn) and zinc (Zn) were assessed. For all species pooled together, leaf Ca and Mg kept relatively stable, whereas leaf K, Fe, Mn and Zn decreased with increasing temperature. The responses of leaf Ca, Mg and Mn to changing temperature were almost similar at functional group, genus and species levels and independent of vegetation and soil type. It suggested that the relationships between leaf Ca, Mg and Mn and temperature should be general results. However, the patterns of leaf K, Fe and Zn vs. temperature varied across functional groups, genera and species and were affected by vegetation and soil type, which indicated that the observed patterns were local phenomena. Our results suggested that global warming might have no effect on leaf Ca and Mg, but could decrease leaf K, Fe, Mn and Zn.

Minimizing the effect of precipitation in clarifying the responses of leaf N and P stoichiometry to temperature.

How terrestrial ecosystem responds to global warming has received wide attention. Plant stoichiometry has the potential to reflect ecosystem responses to climate change, thus, investigating the variations in plant stoichiometry with temperature is important and necessary for revealing the responses of terrestrial ecosystem to global warming. Although many studies had explored the relationships between plant N, P stoichiometry and temperature, previous field investigations did not eliminate the interference of precipitation effect with these observed relationships. To minimize the effect of precipitation on leaf N, P stoichiometry, this investigation was conducted across a temperature gradient over broad geographical scale along the 400 mm isohyet, which extends about 6000 km in China. This study showed that leaf N did not vary, whereas leaf P decreased and leaf N:P ratio increased with increasing mean annual temperature (MAT). The responses of leaf N and P stoichiometry to MAT observed in this study might be general patterns; because they were almost ubiquitous across functional groups, genera and species examined, and moreover, they were independent of vegetation and soil type. It could be inferred from this study that global warming in future will have no effect on leaf N, but reduce leaf P and increase leaf N:P ratio. Stable leaf N and varied leaf P with changing MAT suggested that leaf N and P decoupled with changing temperature.

Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C.

Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.