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Abstract Protected areas are the cornerstones of conservation efforts to mitigate the anthropogenic pressures driving biodiversity loss. Nations aim to protect 30% of Earth’s land and water by 2030, yet the effectiveness of protected areas remains unclear. Here we analyze the performance of over 160,000 protected areas in resisting habitat loss at different spatial and temporal scales, using high-resolution data. We find that 1.14 million km2 of habitat, equivalent to three times the size of Japan, across 73% of protected areas, had been altered between 2003 and 2019. These protected areas experienced habitat loss due to the expansion of built-up land, cropland, pastureland, or deforestation. Larger and stricter protected areas generally had lower rates of habitat loss. While most protected areas effectively halted the expansion of built-up areas, they were less successful in preventing deforestation and agricultural conversion. Protected areas were 33% more effective in reducing habitat loss compared to unprotected areas, though their ability to mitigate nearby human pressures was limited and varied spatially. Our findings indicate that, beyond establishing new protected areas, there is an urgent need to enhance the effectiveness of existing ones to better prevent habitat loss and achieve the post-2020 global biodiversity goals.

Abstract The multiple absorber layer perovskite solar cells (PSCs) with charge transport layers-free (CTLs-free) have drawn widespread research interest due to their simplified architecture and promising photoelectric characteristics. Under the circumstances, the novel design of CTLs-free inversion PSCs with stable and nontoxic three absorber layers (triple Cs3Bi2I9, single MASnI3, double Cs2TiBr6) as optical-harvester has been numerically simulated by utilizing wxAMPS simulation software and achieved high power conversion efficiency (PCE) of 14.8834%. This is owing to the innovative architecture of PSCs favors efficient transport and extraction of more holes and the slender band gap MASnI3 extends the absorption spectrum to the near-infrared periphery compared with the two absorber layers architecture of PSCs. Moreover, the performance of the device with p-type-Cs3Bi2I9/p-type-MASnI3/n-type-Cs2TiBr6 architecture is superior to the one with the p-type-Cs3Bi2I9/n-type-MASnI3/n-type-Cs2TiBr6 architecture due to less carrier recombination and higher carrier life time inside the absorber layers. The simulation results reveal that Cs2TiF6 double perovskite material stands out as the best alternative. Additionally, an excellent PCE of 21.4530% can be obtained with the thicker MASnI3 absorber layer thickness (0.4 µm). Lastly, the highest-performance photovoltaic devices (28.6193%) can be created with the optimized perovskite doping density of around E15 cm3 (Cs3Bi2I9), E18 cm3 (MASnI3), and 1.5E19 cm3 (Cs2TiBr6). This work manifests that the proposed CTLs-free PSCs with multi-absorber layers shall be a relevant reference for forward applications in electro-optical and optoelectronic devices. Graphical Abstract

The placenta, as a “transit station” between mother and fetus, has functions delivering nutrients, excreting metabolic wastes and secreting hormones. A healthy placenta is essential for fetal growth and development while the melatonergic system seems to play a critical physiological role in this organ since melatonin, its synthetic enzymes and receptors are present in the placenta. In current study, Mtnr1a and Mtnr1b knockout mice were constructed to explore the potential roles of melatonergic system played on the placental function and intrauterine growth retardation (IUGR). The result showed that Mtnr1a knockout had little effect on placental function while Mtnr1b knockout reduced placental efficiency and increased IUGR. Considering the extremely high incidence of IURG in sows, the pregnant sows were treated with melatonin. This treatment reduced the incidence of IUGR. All the evidence suggests that the intact melatonergic system in placenta is required for its function. Mechanistical studies uncovered that Mtnr1b knockout increased placental oxidative stress and apoptosis but reduced the angiogenesis. The RNA sequencing combined with histochemistry study identified the reduced angiogenesis and placental vascular density in Mtnr1b knockout mice. These alterations were mediated by the disrupted STAT3/VEGFR2/PI3K/AKT pathway, i.e., Mtnr1b knockout reduced the phosphorylation of STAT3 which is the promotor of VEGFR2. The downregulated VEGFR2 and its downstream elements of PI3K and AKT expressions, then, jeopardizes the angiogenesis and placental development.

The in vitro maturation efficiency of porcine oocytes is relatively low, and this limits the production of in vitro porcine embryos. Since melatonin is involved in mammalian reproductive physiology, in this study, we have explored whether endogenously produced melatonin can help in porcine oocyte in vitro maturation. We have found, for the first time in the literature, that mitochondria are the major sites for melatonin biosynthesis in porcine oocytes. This mitochondrially originated melatonin reduces ROS production and increases the activity of the mitochondrial respiratory electron transport chain, mitochondrial biogenesis, mitochondrial membrane potential, and ATP production. Therefore, melatonin improves the quality of oocytes and their in vitro maturation. In contrast, the reduced melatonin level caused by siRNA to knockdown AANAT (siAANAT) is associated with the abnormal distribution of mitochondria, decreasing the ATP level of porcine oocytes and inhibiting their in vitro maturation. These abnormalities can be rescued by melatonin supplementation. In addition, we found that siAANAT switches the mitochondrial oxidative phosphorylation to glycolysis, a Warburg effect. This metabolic alteration can also be corrected by melatonin supplementation. All these activities of melatonin appear to be mediated by its membrane receptors since the non-selective melatonin receptor antagonist Luzindole can blunt the effects of melatonin. Taken together, the mitochondria of porcine oocytes can synthesize melatonin and improve the quality of oocyte maturation. These results provide an insight from a novel aspect to study oocyte maturation under in vitro conditions.

Pectin methylesterase (PME), a family of enzymes that catalyze the demethylation of pectin, influences seed germination. Phytohormone abscisic acid (ABA) inhibits seed germination. However, little is known about the function of PMEs in response to ABA-mediated seed germination. In this study, we found the role of PME31 in response to ABA-mediated inhibition of seed germination. The expression of PME31 is prominent in the embryo and is repressed by ABA treatment. Phenotype analysis showed that disruption of PME31 increases ABA-mediated inhibition of seed germination, whereas overexpression of PME31 attenuates this effect. Further study found that ABI5, an ABA signaling bZIP transcription factor, is identified as an upstream regulator of PME31. Genetic analysis showed that PME31 functions downstream of ABI5 in ABA-mediated seed germination. Detailed studies showed that ABI5 directly binds to the PME31 promoter and inhibits its expression. In the plants, PME31 expression is reduced by ABI5 in ABA-mediated seed germination. Taken together, PME31 is transcriptionally inhibited by ABI5 and negatively regulates ABA-mediated seed germination inhibition. These findings shed new light on the mechanisms of PMEs in response to ABA-mediated seed germination.

Abstract Background SCNT (somatic cell nuclear transfer) is of great significance to biological research and also to the livestock breeding. However, the survival rate of the SCNT cloned animals is relatively low compared to other transgenic methods. This indicates the potential epigenetic variations between them. DNA methylation is a key marker of mammalian epigenetics and its alterations will lead to phenotypic differences. In this study, ASMT (acetylserotonin-O-methyltransferase) ovarian overexpression transgenic goat was produced by using SCNT. To investigate whether there are epigenetic differences between cloned and WT (wild type) goats, WGBS (whole-genome bisulfite sequencing) was used to measure the whole-genome methylation of these animals. Results It is observed that the different mCpG sites are mainly present in the intergenic and intronic regions between cloned and WT animals, and their CG-type methylation sites are strongly correlated. DMR (differentially methylated region) lengths are located around 1000 bp, mainly distributed in the exonic, intergenic and intronic functional domains. A total of 56 and 36 DMGs (differentially methylated genes) were identified by GO and KEGG databases, respectively. Functional annotation showed that DMGs were enriched in biological-process, cellular-component, molecular-function and other signaling pathways. A total of 10 identical genes related to growth and development were identified in GO and KEGG databases. Conclusion The differences in methylation genes among the tested animals have been identified. A total of 10 DMGs associated with growth and development were identified between cloned and WT animals. The results indicate that the differential patterns of DNA methylation between the cloned and WT goats are probably caused by the SCNT. These novel observations will help us to further identify the unveiled mechanisms of somatic cell cloning technology, particularly in goats.

Abstract Human settlements have an important impact on human health, livability, and the economy, which has attracted widespread concern worldwide. Few studies have, however, paid attention to a comprehensive evaluation of urban and rural areas, as well as subjective and objective aspects. This paper evaluates four dimensions of urban–rural settlements in China, including environmental health, environmental tidiness, environmental amenity, and environmental support, from both subjective and objective perspectives. The findings are summarized as follows: (1) The quality of urban–rural human settlements in China has significantly improved over the last 20 years, and it shows a significant decreasing tendency from the southeastern coastal area to the northwestern inland area spatially. (2) The national average score of subjective estimation of human settlement is at the level of “Satisfied”, and it displays significant disparities in terms of residents’ attributes, such as occupation, age, education, and habitation. (3) The subjective evaluation and subjective well-being have a positive correlation regarding the comprehensive assessment of urban–rural human settlements, but there are significant differences in objective estimation to different sub-dimensions. Long-term follow-up investigation and evaluation should be the focus of future research. Findings provide scientific guidance for the optimization and improvement mechanism of urban–rural human settlements.

As one of the serious complications of sepsis, septic cardiomyopathy has gained more and more attention, because of its high morbidity and mortality. With the in-depth study of septic cardiomyopathy, several methods have been adopted clinically but have poor therapeutic effects due to failure to find precise therapeutic targets. In recent years, microRNAs have been found to be related to the pathogenesis, diagnosis, and treatment of septic cardiomyopathy via regulating immunity and programmed cell death. This paper reviews the role of microRNAs in septic cardiomyopathy, aiming to provide new targets for the diagnosis and treatment of septic cardiomyopathy.

Population growth in the coming decades will lead to increasing land conversion to urban areas. Here, the authors use spatially explicit projections of global urban expansion to analyze its effects on habitat changes, and terrestrial mammals, birds and amphibians under the main shared socioeconomic pathways.

Solid oxide electrolysis cells (SOECs) have emerged as one of the most potent techniques for hydrogen production. As the restricted step for SOEC, as well as the most predominant obstacle to the scaled application, oxygen evolution reaction (OER) should be urgently accelerated by developing potent electrocatalysts. Despite inferior electrochemical activity to cobalt-based materials, perovskite ferrites exhibit great potential in the future with regard to good intrinsic stability and durability, abundant reserves, and good compatibility with other SOEC components. In this work, fluorination is introduced to the typical perovskite ferrite to further intensify the OER process. Ab initio calculations combined with physical–chemical characterizations are performed to reveal the mechanism. The doped F− leads to debilitating the strength of the metal–oxygen bond and then reduces the energy for oxygen vacancy formation and ion migration, which renders improvements to sub-processes of OER on the anode. The well-verified material, PrBaFe2O5+δF0.1 (PBFOF), exhibited a low polarization resistance of 0.058 Ω cm−2. Single cells based on PBFOF showed a high current density of 2.28 A cm−2 at 750 °C under 1.3 V. This work provides a clear insight into the mechanism of fluorination on perovskites and high-activity anode material for SOEC.

The fermented feed has been used extensively as a growth promoter in agricultural animal production. However, the effects of fermented feed on swine gut microbiota are still largely unknown. The work presented here aimed to investigate the growth performance and gut microbiota of nursery pigs receiving the LPF diet (10% Lactobacillus plantarum and Pediococcus acidilactici co-fermented feed + basal diet) compared with pigs receiving the NC diet (basal diet). The data showed LPF diet numerically improved average daily gain and significantly increased fecal acetate, butyrate, and total short-chain fatty acid (SCFA) concentrations. Furthermore, gut microbiota structure and membership significantly changed in response to the addition of fermented feed in the diet. Gut microbiota results indicated that LPF treatment significantly enriched SCFA-producing bacteria such as Megasphaera, Roseburia, Faecalibacterium, Blautia, Selenomonas, Dialister, Acidaminococcus, Ruminococcus, and Bifidobacterium. Some of these bacteria also had anti-inflammatory and other beneficial functions. Overall, these findings suggested that Lactobacillus plantarum and Pediococcus acidilactici co-fermented feed benefited growth performance and established potential health impacts on the gut microbiota of nursery pigs.

Melatonin is an indole-like neuroendocrine hormone. A large number of studies have shown that melatonin can improve production performance of ewes, but it is not clear in lambs. In this study, the growth and development of the 2-month-old lambs implanted with melatonin were monitored for 60 days. The results showed that the growth rate of body weight and body skew length of lambs with melatonin treatment were significantly improved compared to the controls. The similar results were also observed in red blood cell count, hematocrit, red blood cell volume distribution width, the levels of growth hormone, testosterone, immunoglobulin A, immunoglobulin M and albumin. In addition, the cross sectional area of muscle fibers and adipose cells of lambs with melatonin implantation were also significantly increased compared to the controls (P

China has led global greening processes over recent decades, however, a series of negative impacts have inevitably emerged in some areas, especially on the Loess Plateau. While the potential for afforestation of the Loess Plateau has been identified, the micro-regions where afforestation should be prioritized have yet to be identified. We constructed a framework for identification of land suitable for forest on the Loess Plateau. By simulating land-use changes on the Loess Plateau under various development scenarios for the period from 2020 to 2030, we identified land that is suitable for afforestation and explored the trends and spatial distribution of different forest stands. The results show that only ∼ 40 km2 on the Loess Plateau is suitable for forest growth by 2030, mainly in the eastern region, with the southeastern part of the Loess Plateau at greater risk of degradation. The suitable land for forest growth is fragmented. Under the current climate conditions and policy background, we believe there is limited opportunity for large-scale conversion of farmland to forest on the Loess Plateau; however, if the afforestation areas are scientifically planned, it is feasible to achieve greening in local areas. Grasslands may be a more suitable primary approach to ecological restoration in the Loess Plateau region. The results will help guide more efficient and sustainable afforestation projects in the Loess Plateau region.

Urban green space has a critical impact on the urban ecological environment, residents’ health, and urban sustainability. Quantifying residential exposure to green space and proposing targeted enhancement strategies in urban areas is helpful to rationally plan urban green space construction, reduce the inequality in residential exposure to green space, and promote environmental equity. However, the long-time evolution analysis of residential exposure to green space at different scales and the influence of green space quality on residential exposure to green space are rarely reported. Here we produced a long-time series dataset of urban green space from 1990 to 2020 based on the 30 m Landsat data and used the Normalized Difference Vegetation Index (NDVI) as a representation of the green space quality to comprehensively analyze residential exposure to green space at the city and block scales within the 5th ring of Beijing, China. We found that the urban green space in Beijing is mainly distributed in urban areas between the 4th and 5th rings (i.e., 153.4 km2 in 2020), and there is little green space within the 2nd ring area (i.e., 12.6 km2 in 2020). There is clear spatial inequality in residential exposure to green space, and about 2.88 million (i.e., ~27%) residents have experienced different degrees of decline in residential exposure to green space from 2015 to 2020. However, the degree of inequality in residential exposure to green space has gradually weakened from a high level (Palma ratio = 2.84) in 1990 to a relatively low level (Palma ratio = 0.81) in 2020. In addition, the spatial-temporal analysis method of residential exposure to green space based on green space quality has certain advantages that can help explore the degraded and lost areas of green space.

In this study, the effects of daily melatonin supplementation (2 mg/kg) at the late gestational stage on the reproductive performance of the sows have been investigated. This treatment potentially increased the litter size and birth survival rate and significantly increased the birth weight as well as the weaning weight and survival rate of piglets compared to the controls. The mechanistic studies have found that these beneficial effects of melatonin are not mediated by the alterations of reproductive hormones of estrogen and progesterone, nor did the glucose and lipid metabolisms, but they were the results of the reduced oxidative stress in placenta associated with melatonin supplementation. Indeed, the melatonergic system, including mRNAs and proteins of AANAT, MTNR1A and MTNR1B, has been identified in the placenta of the sows. The RNA sequencing of placental tissue and KEGG analysis showed that melatonin activated the placental tissue fluid shear stress pathway to stimulate the Nrf2 signaling pathway, which upregulated its several downstream antioxidant genes, including MGST1, GSTM3 and GSTA4, therefore, suppressing the placental oxidative stress. All these actions may be mediated by the melatonin receptor of MTNR1B.

ObjectiveIn this study, two experiments were performed to assess the effect and the role of melatonin on human in vitro embryo quality.MethodsExperiment I: A total of 42 repeated-poor-quality-embryo patients were enrolled, with a total of 181 oocytes retrieval cycles. After IVF, for the same patient, the MT cycles group (10-7 M melatonin added to the culture medium; n=48) were compared with the previous non-MT cycles group (n=133), following by in vitro culture to blastocyst stage and embryo transfer. 31 patients were transplanted with 65 embryo transfer, including 24 MT embryo transfer, 41 non-MT embryo transfer. Cycle outcomes were compared between the two groups. Experiment II:A total of 143 supernumerary human cleavage-stage embryos (from non-repeated-poor-quality-embryo patients) vitrified on Day 3 after IVF were warmed and randomized into two groups: melatonin group (10-7 M melatonin added to the culture medium; n=71) and control group (n=72), and then cultured for 72 h. Rate of blastocyst and high-quality blastocyst, reactive oxygen species (ROS) levels of culture media as well as embryonic GPX1, CAT, Mn-SOD, Cu/Zn-SOD, BCL-2, BAX gene expression levels were analyzed.ResultsExperiment I: Results showed that the rate of Day 3 high-quality embryos (29.6% vs.19.5%) in the MT cycles group was significantly higher than that in the non-MT cycles group (P0.05). Experiment II:Results showed that the blastocyst rates in the melatonin administered group were significantly higher than in control group (42.25% vs.26.38%, P

Carbon neutrality is becoming an important development goal for regions and countries around the world. Land-use cover/change (LUCC), especially urban growth, as a major source of carbon emissions, has been extensively studied to support carbon-neutral planning. However, studies have typically used methods of small-scale urban growth simulation to model urban agglomeration growth to assist in carbon-neutral planning, ignoring the significant characteristics of the process to achieve carbon neutrality: large-scale and long-term. This paper proposes a framework to model large-scale and long-term urban growth, which couples a quantity module and a spatial module to model the quantity and spatial allocation of urban land, respectively. This framework integrates the inertia of historical land-use change, the driving effects of the urbanization law (S-curve), and the traction of the urban agglomeration network to model the long-term quantity change of urban land. Moreover, it couples a partitioned modeling framework, spatially heterogeneous rules derived by geographically weighted regression (GWR), and quantified land-use planning orientations to build a cellular automata (CA) model to accurately allocate the urbanized cells in a large-scale spatial domain. Taking the Guangdong–Hong Kong–Macao Greater Bay Area (GHMGBA) as an example, the proposed framework is calibrated by the urban growth from 2000 to 2010 and validated by that from 2010 to 2020. The figure of merit (FoM) of the results simulated by the framework is 0.2926, and the simulated results are also assessed by some evidence, which both confirm the good performance of the framework to model large-scale and long-term urban growth. Coupling with the coefficients proposed by the Intergovernmental Panel on Climate Change (IPCC), this framework is used to project the carbon emissions caused by urban growth in the GHMGBA from 2020 to 2050. The results indicate that Guangzhou, Foshan, Huizhou, and Jiangmen are under great pressure to achieve the carbon-neutral targets in the future, while Hong Kong, Macao, Shenzhen, and Zhuhai are relatively easy to bring up to the standard. This research contributes to the ability of land-use models to simulate large-scale and long-term urban growth to predict carbon emissions and to support the carbon-neutral planning of the GHMGBA.

Information regarding the dynamic change of urban green space (UGS) at fine spatiotemporal resolutions is important for developing sustainable urban environments and understanding urban ecosystems in the future. As the capital of China, due to population explosion, economic growth, and redevelopment of inner-city areas, Beijing underwent extremely rapid urbanization in the past few years, which is intensifying the contradiction between human activities and UGS. Timely monitoring of Beijing’s dynamic change of UGS is very important for the planning of the capital’s living environment. Hence, a novel framework was proposed to map the dynamic change of UGS from 2000 to 2018 by integrating social sensing data and time series remote sensing data. First, we generated a dynamic mapping of the vegetation and a mapping of the annual maximum value of the Nominalized Difference Vegetation Index (NDVImax), using time series Landsat images on a Google Earth Engine platform. Then, a temporal segmentation approach was implemented to identify the turning years and using a decision tree approach determine the historical time of social sensing data. Finally, the UGS mapping and its dynamics were generated according to the identified time parameter of social sensing data, as well as remote sensing data. Our results showed that the temporal segmentation approach is reliable for detecting urban changes and identifying the historical time of social sensing data, with an overall accuracy of 90%. The overall classification accuracies of UGS are 0.87 (both Level 1 and Level 2). Moreover, the UGS area continuously increased from 2000 to 2018, of which the dominant types are residential green space and theme parks. The proposed framework provides an effective tool for better understanding the dynamic change of UGS, and the results from this work present vital insights for planners and government departments to develop targeted measures and protect UGS effectively.

Exploring how human settlement expansion affects landscape fragmentation is particularly critical to understanding the complex interactions between human activities and landscape functions, patterns, and processes. Here, we use recently developed built-up data and land use data to characterize this effect and its spatial–temporal heterogeneity between 1975 and 2014 in China based on the grids at the national level. Findings suggest that the mean built-up ratio has enlarged three-fold in the past 40 years. The landscape pattern has become increasingly fragmented. Due to anthropogenic encroachment, human settlement expansion has become directly associated with natural habitat loss. Meanwhile, the swift growth of settlements leads to landscape fragmentation with a snowballing number of patches and reducing mean patch size. However, landscape isolation is negatively correlated with settlement expansion. Contrary to traditional perception, the influence of settlement growth on landscape fragmentation in large cities is not as pronounced as that of small and medium cities. Furthermore, there are significant regional differences and gradient effects in the impact of settlement expansion on landscape fragmentation. Specifically, this impact is most intense in western China, followed by central China, and the weakest in eastern China. Several innovative policy implications of these findings are discussed.

Background: Transgenic animal production is an important means of livestock breeding and can be used to model pharmaceutical applications. Methods: In this study, to explore the biological activity of endogenously produced melatonin, Acetylserotonin-O-methyltransferase (ASMT)-overexpressed melatonin-enriched dairy goats were successfully generated through the use of pBC1-ASMT expression vector construction and prokaryotic embryo microinjection. Results: These transgenic goats have the same normal phenotype as the wild-type goats (WT). However, the melatonin levels in their blood and milk were significantly increased (p < 0.05). In addition, the quality of their milk was also improved, showing elevated protein content and a reduced somatic cell number compared to the WT goats. No significant changes were detected in the intestinal microbiota patterns between groups. When the animals were challenged by the intravenous injection of E. coli, the ASMT-overexpressed goats had a lower level of pro-inflammatory cytokines and higher anti-inflammatory cytokines compared to the WT goats. Metabolic analysis uncovered a unique arachidonic acid metabolism pattern in transgenic goats. Conclusions: The increased melatonin production due to ASMT overexpression in the transgenic goats may have contributed to their improved milk quality and enhanced the anti-inflammatory ability compared to the WT goats.

A planar device structure FTO/TiO _2 /SnO _2 /Cs _0.1 [HC(NH _2 ) _2 ] _0.74 (CH _3 NH _3 ) _0.13 PbI _2.48 Br _0.39 (Cs _0.1 FA _0.74 MA _0.13 PbI _2.48 Br _0.39 )/CuSCN/Au with cation and anion co-mixed Cs _0.1 FA _0.74 MA _0.13 PbI _2.48 Br _0.39 as light harvester was modeled and investigated by using modeling program wxAMPS. The energy band structure, carrier concentration, carrier generation rate, recombination rate, and other data were obtained through simulation to analyze the specific influence on the performance of perovskite solar cells (PSCs). In order to better optimize device performance, we investigated the effects of perovskite and the interface between each functional layer defect density, film thickness, and test temperature environment on the performance of PSCs. The simulation results show that the device performance has higher dependence on the effect of perovskite and interface defect density. By further optimizing the parameters of defect density (10 ^13 cm ^−3 ), film thickness (400 nm), and test temperature (300 K), the power conversion efficiency (PCE) of the finally obtained PSCs was enhanced from the initial 11.65% to 21.95%. This investigation will enable us to better understand the internal working mechanism of PSCs and provide theoretical guidance for the fabrication of high-performance PSCs in experiments.

The investigation of crystal growth is crucial for us to improve the film quality and photophysical properties of CH3NH3PbI3 (MAPbI3). In the two-step spin-coating process, the crystal structure could be modulated by controlling the growth conditions of PbI2 and CH3NH3I (MAI) layers. In this paper, the PbI2 layer was treated with annealing under different times. A liquid–liquid diffusion (LLD) mechanism is proposed to modify the deposition of MAI precursor solution and enhance the flatness of organic–inorganic hybrid perovskite film. Furthermore, the perovskite films are prepared using different concentrations of MAI. The evolution process of perovskite structure is observed by modulating the concentration of MAI. The spin-coating of moderate MAI tends to form high quality MAPbI3 films with enhanced absorption and carrier extraction capabilities. The high concentration of MAI would cause the perovskite phase transition, which provides a novel perspective to modulate the structure of organic–inorganic hybrid perovskite in the two-step spin-coating process, although it deteriorates the device performance.

The film quality of the electron transport layer (ETL) plays an important role in improving the performance of perovskite solar cells (PSCs). In order to reduce the effect of rough fluorine-doped SnO2 (FTO)substrate on the film quality of the TiO2 ETL, multiple cycles of spin-coating were employed to realize optimized TiO2 film and improve the performance of PSCs with rough FTO. The results show that TiO2 ETL was optimized most effectively using two spin-coating cycles, obtaining the best performance of PSCs with rough FTO. The carbon electrode-based PSCs were then demonstrated. Our work discusses the feasibility of low-quality rough FTO for the fabrication of PSCs and photodetectors to reduce costs.

Flexible perovskite solar cells (PSCs) have received increasing attention in wearable and portable devices over the past ten years. The low-temperature process of electron transport layer plays a key role in fabricating flexible PSCs. In this paper, we improve the performance of flexible PSCs by controlling the thermodynamic procedure in the low-temperature annealing process of solution-processed TiO2 layers and modulating the precursor concentration of (6,6)-phenyl c61 butyric acid methyl ester (PC61BM) deposited on fluorine-doped tin oxide (FTO)/TiO2 substrate. The results show that slowing down evaporation rate of residual solvent and adopting PC61BM of appropriate precursor concentration are confirmed to be effective methods to improve the performance of flexible PSCs. We also demonstrate carbon electrode-based flexible PSCs. Our work expands the feasibility of low temperature process for the development of flexible perovskite photodetectors and light-emitting diodes, as well as flexible PSCs.

In recent years, flexible perovskite solar cells have drawn tremendous attention in the field of wearable devices, and optimization of perovskite composition plays an important role in improving film quality and photophysical properties. At present, some researchers have only studied A-site organic cations mixing or X-site halide anions mixing in the ABX3 structure of perovskite, but there are few reports on co-mixing of A-site and X-site ions in flexible perovskite solar cells. In this paper, we mainly try to study the effects of different concentrations of mixed formamidine methylamine halide (FAxMA1-xBrxClyI1-x-y) precursor solutions on the quality and photophysical properties of perovskite films under low temperature process. We conclude that the film quality and photophysical properties reached the best results when the optimized precursor solution concentration was 60:6:6. The investigation on composition optimization in this experiment laid the foundation for the improvement of the performance of flexible perovskite solar cells. We also use the results of this experiment to prepare flexible perovskite solar cells based on carbon electrodes, which are expected to be applied in other flexible optoelectronic or electro-optical devices.

Energy band alignment between perovskite layer and charge transport layers is critical to the perovskite solar cell efficiency. The thickness of functional layers also has a great influence on the device performance. We have optimized the energy band alignment at the interface between electron transport layer (ETL) and perovskite layer by using appropriate Cd _1-x Zn _x S ETL (x represents the Zn molar concentration). Different hole transport layers (HTLs) have also been selected to address the mismatching energy band alignment at perovskite/HTL interface. Additionally, the thickness of Cd _1-x Zn _x S ETL and perovskite layer (MAPbI _3 ) has been optimized. We performed all the analysis via numerical simulation with wx Analysis of Microelectronic and Photonic Structures (wxAMPS) software. We also compared the results obtained in this study, with results reported in other literature to ascertain the validity of the results. The results show that the device performance could be improved by appropriately increasing the molar concentration of Zn in Cd _1-x Zn _x S. Spike-type energy band structure at the interface of MAPbI _3 /HTL could favor the performance of perovskite solar cells when MASnBr _3 is adopted as HTL. Appropriate ETL and perovskite layer thickness would increase the short circuit current and reduce the recombination loss.

This paper empirically investigated the spatiotemporal variations, influencing factors and future emission trends of China's CO2 emissions based on a provincial panel data set. A series of panel econometric models were used taking the period 1995-2011 into consideration. The results indicated that CO2 emissions in China increased over time, and were characterized by noticeable regional discrepancies; in addition, CO2 emissions also exhibited properties of spatial dependence and convergence. Factors such as population scale, economic level and urbanization level exerted a positive influence on CO2 emissions. Conversely, energy intensity was identified as having a negative influence on CO2 emissions. In addition, the significance of the relationship between CO2 emissions and the four variables varied across the provinces based on their scale of economic development. Scenario simulations further showed that the scenario of middle economic growth, middle population increase, low urbanization growth, and high technology improvement (here referred to as Scenario BTU), constitutes the best development model for China to realize the future sustainable development. Based on these empirical findings, we also provide a number of policy recommendations with respect to the future mitigation of CO2 emissions.

The inferior oocytes (IOs), which are not suitable for embryo development, occupy roughly one-third or more of the collected immature bovine oocytes. The IOs are usually discarded from the in vitro bovine embryo production process. Improving the quality of the inferior oocytes (IOs) and make them available in in vitro embryo production would have important biological, as well as commercial, value. This study was designed to investigate whether melatonin could improve the quality of IOs and make them usable in the in vitro maturation (IVM) and subsequent (in vitro fertilization) IVF embryo development. The results indicated that: the maturation rate of IOs and their subsequent IVF embryo developments were impaired compared to cumulus-oocyte complexes and melatonin treatment significantly improved the quality of IOs, as well as their IVF and embryo developments. The potential mechanisms are that: (1) melatonin reduced reactive oxygen species (ROS) and enhanced glutathione (GSH) levels in the IOs, thereby protecting them from oxidative stress; (2) melatonin improved mitochondrial normal distribution and function to increase ATP level in IOs; and (3) melatonin upregulated the expression of ATPase 6, BMP-15, GDF-9, SOD-1, Gpx-4, and Bcl-2, which are critical genes for oocyte maturation and embryo development and downregulated apoptotic gene expression of caspase-3.

The relations between geographical proximity and spatial distance constitute a popular topic of concern. Thus, how geographical proximity affects scientific cooperation, and whether geographically proximate scientific cooperation activities in fact exhibit geographic scale features should be investigated.Selected statistics from the ISI database on cooperatively authored papers, the authors of which resided in 60 typical cites in China, and which were published in the years 1990, 1995, 2000, 2005, and 2010, were used to establish matrices of geographic distance and cooperation levels between cities. By constructing a distance-cooperation model, the degree of scientific cooperation based on spatial distance was calculated. The relationship between geographical proximity and scientific cooperation, as well as changes in that relationship, was explored using the fitting function.(1) Instead of declining, the role of geographical proximity in inter-city scientific cooperation has increased gradually but significantly with the popularization of telecommunication technologies; (2) the relationship between geographical proximity and scientific cooperation has not followed a perfect declining curve, and at certain spatial scales, the distance-decay regularity does not work; (3) the Chinese scientific cooperation network gathers around different regional center cities, showing a trend towards a regional network; within this cooperation network the amount of inter-city cooperation occurring at close range increased greatly.The relationship between inter-city geographical distance and scientific cooperation has been enhanced and strengthened over time.

Formaldehyde is an important carcinogen commonly found indoors. Its indoor sources have been intensively investigated. But study on outdoor formaldehyde concentration, which is potentially an important source to indoors, remains scarce. This study attempts to characterize temporal and spatial distribution of the atmospheric formaldehyde concentration in Chinese cities. Diurnal variation of ambient formaldehyde was examined in 6 cities and peak hours were identified between 12:00 pm and 3:00 pm. Consequently, outdoor formaldehyde concentrations were measured in the peak hours in 30 cities during the summer months of Jul.-Aug., 2022. The formaldehyde concentrations in the peak hours fell into a range of 0.005–0.087 mg/m3 (median value is 0.027 mg/m3), 87.7% of which have exceeded the chronic reference exposure criteria of 0.009 mg/m3 set by Office of Environmental Health Hazard Assessment. Health risk analysis suggests that exposure to ambient formaldehyde could cause a median carcinogenic risk of 1.9 × 10−5 (3.17×10−6–6.13×10−5), higher than threshold limit of 10−6. Pearson correlation analysis of the 30 cities shows that ambient summertime atmospheric formaldehyde concentrations of the city are positively correlated with its Gross Domestic Product (r = 0.48). We also found that the outdoor formaldehyde concentrations in urban areas (median: 0.017 mg/m3) is slightly higher than those in suburban areas (median: 0.013 mg/m3). Results here prove that outdoor formaldehyde is ubiquitous in Chinese cities and reduces effectiveness of ventilation in dilution indoor concentrations. Neglecting it would underestimate air cleaner capacity needed by a factor of about two. It should be accounted for in health analysis and air quality engineering control design of built environment in the future.