Giant Superlinear Power Dependence of Photocurrent Based on Layered Ta2 NiS5 Photodetector.

Photodetector based on two-dimensional (2D) materials is an ongoing quest in optoelectronics. 2D photodetectors are generally efficient at low illuminating power but suffer severe recombination processes at high power, which results in the sublinear power-dependent photoresponse and lower optoelectronic efficiency. The desirable superlinear photocurrent is mostly achieved by sophisticated 2D heterostructures or device arrays, while 2D materials rarely show intrinsic superlinear photoresponse. This work reports the giant superlinear power dependence of photocurrent based on multilayer Ta2 NiS5 . While the fabricated photodetector exhibits good sensitivity (3.1 mS W-1 per □) and fast photoresponse (31 µs), the bias-, polarization-, and spatial-resolved measurements point to an intrinsic photoconductive mechanism. By increasing the incident power density from 1.5 to 200 µW µm-2 , the photocurrent power dependence varies from sublinear to superlinear. At higher illuminating conditions, prominent superlinearity is observed with a giant power exponent of γ = 1.5. The unusual photoresponse can be explained by a two-recombination-center model where density of states of the recombination centers (RC) effectively closes all recombination channels. The photodetector is integrated into camera for taking photos with enhanced contrast due to superlinearity. This work provides an effective route to enable higher optoelectronic efficiency at extreme conditions.

Topological Lifshitz transition and one-dimensional Weyl mode in HfTe5.

Landau band crossings typically stem from the intra-band evolution of electronic states in magnetic fields and enhance the interaction effect in their vicinity. Here in the extreme quantum limit of topological insulator HfTe5, we report the observation of a topological Lifshitz transition from inter-band Landau level crossings using magneto-infrared spectroscopy. By tracking the Landau level transitions, we demonstrate that band inversion drives the zeroth Landau bands to cross with each other after 4.5 T and forms a one-dimensional Weyl mode with the fundamental gap persistently closed. The unusual reduction of the zeroth Landau level transition activity suggests a topological Lifshitz transition at 21 T, which shifts the Weyl mode close to the Fermi level. As a result, a broad and asymmetric absorption feature emerges due to the Pauli blocking effect in one dimension, along with a distinctive negative magneto-resistivity. Our results provide a strategy for realizing one-dimensional Weyl quasiparticles in bulk crystals.

High-Performance Resistive Random Access Memories Based on Two-Dimensional HAPbI4 Organic-Inorganic Hybrid Perovskite.

Organic-inorganic hybrid perovskites have attracted extensive attention for potential memory applications because of their excellent properties, such as high charge carrier mobility and fast ion migration. Herein, the two-dimensional HAPbI4 perovskite with an octahedral structure and high stability was prepared by a facile solution method. Moreover, the resistive random access memory (RRAM) with the Ag/PMMA/HAPbI4/ITO structure has been successfully fabricated by spin coating and vacuum thermal evaporation. The as-prepared RRAM device based on HAPbI4 demonstrated superior resistive switching performance. The on/off ratio is as high as 105, and the corresponding retention of the device exceeds 10 000 s; furthermore, the RRAM device could be kept stable after being kept in the air for 24 weeks.

Association between hospitalizations for asthma exacerbation and weather conditions in Qingdao: an ecological study.

Background: The hospitalization for asthma exacerbation has varied with seasons, however, the underlying weather reasons have not been fully explored yet. This study is aimed to explore the effect of weather factors on increased number of hospitalization due to worsening of asthma symptoms. This will provide more information to the relevant authorities to allocate appropriate medical resources as per the weather conditions in Qingdao, China. Methods: All adult patients admitted for asthma exacerbation from 1 January, 2017 to 31 December, 2019 were enrolled from 13 main hospitals of Qingdao. The clinical data, including age, sex, smoking history, etc., were collected from the electronic medical record (EMR) systems. The hourly air quality of Qingdao from 2017-2019, including the air quality index (AQI), PM2.5 and PM10, was obtained from the China National Environmental Monitoring Centre. All these parameters during 2017-2019 were compared monthly. For meteorological data, the monthly horizontal wind at 850 hPa and vertical velocity at 500 hPa during 1960-2020 were obtained from National Center for Environmental Prediction (NCEP) and the National Center for Atmospheric Research (NCAR) global reanalysis dataset. The correlation analysis was applied to determine the association between asthma hospitalizations and the environmental factors, including atmospheric pressure, humidity, vertical visibility, and etc., monthly. Results: In all, 10,549 asthmatic inpatients (45.7% males, 54.3% females) were included in the study. The inpatients number for asthma exacerbation had a plateau lasting from March to June of 2019, accompanied with high PM2.5 and PM10, as well as bad air quality from January to March of 2019, potentially governed by the El Niño event in 2018. However, there was no significance correlation between the number of asthma hospitalizations and the average value of all environmental factors. Conclusions: The high rate of hospitalization for asthma exacerbation in Qingdao during the spring of 2019 was associated with the unfavorable weather conditions, which might be linked to the atmospheric circulation in East Asia.

The Driving Influence of Multi-Dimensional Urbanization on PM2.5 Concentrations in Africa: New Evidence from Multi-Source Remote Sensing Data, 2000-2018.

Africa's PM2.5 pollution has become a security hazard, but the understanding of the varying effects of urbanization on driven mechanisms of PM2.5 concentrations under the rapid urbanization remains largely insufficient. Compared with the direct impact, the spillover effect of urbanization on PM2.5 concentrations in adjacent regions was underestimated. Urbanization is highly multi-dimensional phenomenon and previous studies have rarely distinguished the different driving influence and interactions of multi-dimensional urbanization on PM2.5 concentrations in Africa. This study combined grid and administrative units to explore the spatio-temporal change, spatial dependence patterns, and evolution trend of PM2.5 concentrations and multi-dimensional urbanization in Africa. The differential influence and interaction effects of multi-dimensional urbanization on PM2.5 concentrations under Africa's rapid urbanization was further analyzed. The results show that the positive spatial dependence of PM2.5 concentrations gradually increased over the study period 2000-2018. The areas with PM2.5 concentrations exceeding 35 µg/m3 increased by 2.2%, and 36.78% of the African continent had an increasing trend in Theil-Sen index. Urbanization was found to be the main driving factor causing PM2.5 concentrations changes, and economic urbanization had a stronger influence on air quality than land urbanization or population urbanization. Compared with the direct effect, the spillover effect of urbanization on PM2.5 concentrations in two adjacent regions was stronger, particularly in terms of economic urbanization. The spatial distribution of PM2.5 concentrations resulted from the interaction of multi-dimensional urbanization. The interaction of urbanization of any two different dimensions exhibited a nonlinear enhancement effect on PM2.5 concentrations. Given the differential impact of multi-dimensional urbanization on PM2.5 concentrations inside and outside the region, this research provides support for the cross-regional joint control strategies of air pollution in Africa. The findings also indicate that PM2.5 pollution control should not only focus on urban economic development strategies but should be an optimized integration of multiple mitigation strategies, such as improving residents' lifestyles, optimizing land spatial structure, and upgrading the industrial structure.

Spatial Analysis of Citizens' Environmental Complaints in China: Implications in Environmental Monitoring and Governance.

Citizen environmental complaints play a key role in China's current environmental monitoring network and environmental governance system. Based on 5796 cases of environmental complaints lodged by citizens via hotline and the internet to the MEP of China, we examined the spatial characteristics and influencing factors of citizen complaints for the period of 2013-2017 using spatial analysis methods and spatial econometric models. The roles of citizen complaints in the two systems were then reevaluated. The results show that, among all cases, 75.88% of cases were identified as verified complaints, while nearly a 25% noisy rate directed large amounts of inspection resources to be utilized in response to nonverified cases. Air pollution received the most attention by citizens in China, accounting for 67.22% of total cases. The hotspots of citizen complaints were mostly distributed in the three major national urban agglomerations in China. We found that industrial wastewater and SO2 were positively associated with the likelihood of citizens filing complaints, while the effect of industrial soot/dust emission was insignificant. Citizen complaints might be triggered by certain, but not all, forms of pollutants, even though highly visible particulate pollutants did not necessarily induce corresponding complaints. Moreover, the negative relationship between citizen complaints and per capita GDP revealed the unbalanced geographical pattern between economical development and environmental quality. The proliferation of the internet greatly facilitated citizens lodging complaints through various ways. The synergy mechanism between citizen environmental complaints and other parts in China's environmental monitoring and governance system should be established in the future.

Exploring Spatial Variations in the Relationships between Landscape Functions and Human Activities in Suburban Rural Communities: A Case Study in Jiangning District, China.

There is a complicated and contradictory relationship between landscape functions and human activities, especially in the suburban rural communities of metropolises. Previous studies focused on human interference to landscape function, ignoring the impact of landscape functions on human activities. Hence, the present study is focused on the impact of landscape function (based on ecosystem services) on human activities in suburban rural communities of China. The study evaluated the intensity of human activities based on big data; furthermore, the authors analyzed the spatial distribution characteristics through spatial autocorrelation, and probed into the spatial variations in the relationship between human activities and landscape functions using ordinary least squares (OLS) and geographically weighted regression (GWR) models. The result indicates that there are obvious spatial distribution differences in the intensity of human activities in suburban rural communities; that is, the intensity decreases from the inner to the outer suburban areas. Positive influencing factors of human activities are construction area, bus station, road network density, and leisure entertainment, among which, construction area is the principal driver; cultural heritage, hydrological regulation, and provision of aesthetics are negatively or positively correlated with human activities in various regions. The results offer insights for the sustainable development of rural environment in suburban areas and the big data-driven rural research.

Recent Evolution of the Intertidal Sand Ridge Lines of the Dongsha Shoal in the Modern Radial Sand Ridges, East China.

The Dongsha Shoal is one of the largest shoals in the South Yellow Sea and has important marine ecological value. The shoal extends in a south-north direction and is controlled by the regional dominating tidal currents. Recently, due to human activities and some natural factors, the geomorphic dynamics of the Dongsha Shoal has undergone drastic changes. However, few people have proposed quantitative research on the changes of tidal flat morphology, let alone the long-term sequence analysis of sand ridge lines. Hence, we attempt to take the Dongsha Shoal in the Radial Sand Ridges as the research area, and analyze the trends of the long-term morphological evolution of the sand ridge lines over the period 1973-2016 based on a high-density time series of medium-resolution satellite images. The sand ridge line generally moves from southeast to northwest, and the position distribution of the sand ridge line from north to south has gradually changed from compact to scattered. We also found that the geomorphological dynamics at different positions of the sand ridge line are inconsistent. The north and south wings are eroded on the west side, while the central area is eroded on the east side. Most of the sand ridge line is moving eastward. In addition, the change of sand ridge line is affected by multiple factors such as sediment supply, typhoon, reclamation and laver cultivation.

The Improvement of CRISPR-Cas9 System With Ubiquitin-Associated Domain Fusion for Efficient Plant Genome Editing.

Genome editing technology represented by CRISPR-Cas9 had been widely used in many biological fields such as gene function analysis, gene therapy, and crop improvement. However, in the face of the complexity of the eukaryotic genome, the CRISPR-Cas9 genome editing tools have shown an unstable editing efficiency with large variability at different target sites. It was important to further improve the editing efficiency of the CRISPR-Cas9 system among the whole genome. In this study, based on the previous single transcription unit genome editing system (STU-SpCas9), using the ubiquitin-associated domain (UBA) to enhance the stability of Cas9 protein, we constructed three Cas9-UBA fusion systems (SpCas9-SD01, SpCas9-SD02, and SpCas9-SD03). Four different target sites of rice OsPDS, OsDEP1 and OsROC5 genes were chosen to evaluate the genome editing efficiency in rice protoplasts and stable transformed rice plants. The results showed that the fusion of UBA domains did not affect the cleavage mode of Cas9 protein, and effectively increase the editing efficiency of STU-SpCas9 at the target sites. This new CRISPR-Cas9-UBA system provided a new strategy and tool for improving the genome editing efficiency of CRISPR-Cas9 in plants.

Intron-Based Single Transcript Unit CRISPR Systems for Plant Genome Editing.

BACKGROUND: Expression of either Cas9 or Cas12a and guide RNAs by a single Polymerase II (Pol II) promoter represents a compact CRISPR expression system and has many advantages for different applications. In order to make this system routine in plant biology, engineering efforts are needed for developing and optimizing such single transcript unit (STU) systems for plant genome editing. RESULTS: To develop novel intron-based STU (iSTU) CRISPR system (STU CRISPR 3.0), we first evaluated three introns from three plant species for carrying guide RNAs by using an enhanced green fluorescence protein (eGFP) system in rice. After validation of proper intron slicing, we inserted these gRNA-containing introns into the open reading frames (ORFs) of Cas9 and Cas12a for testing their genome editing capability. Different guide RNA processing strategies have been tested for Cas9 and Cas12a. We demonstrated singular genome editing and multiplexed genome editing with these iSTU-Cas9 and iSTU-Cas12a systems. CONCLUSION: We developed multiple iSTU-CRISPR/Cas9 and Cas12a systems for plant genome editing. Our results shed light on potential directions for further improvement of the iSTU systems.

Size-Dependent Structural Properties of a High-Nb TiAl Alloy Powder.

TiAl-based alloys are promising light weight structural materials for high temperature applications in the field of aerospace. Recently, fabrication technologies starting from powders including powder metallurgy and additive manufacturing have been developed to overcome the difficulties in the processing, machining and shaping of TiAl-based alloys. Spherical alloy powders with different particle size distributions are usually used in these fabrication techniques. The purpose of this study is to reveal the size-dependent structural properties of a high-Nb TiAl powder for these fabrication technologies starting from powders. A high-Nb TiAl pre-alloyed powder with nominal composition of Ti-48Al-2Cr-8Nb (at. %) was prepared by the electrode induction melting gas atomization (EIGA) method. The phase structure and morphology of the as-atomized powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The size-dependent structural changes of the as-atomized powders with different sizes were studied by differential scanning calorimetry (DSC) and in situ high temperature XRD. It was found that with decreasing the powder size, the content of the γ-TiAl phase decreases and the α2-Ti3Al phase increases. The α2-Ti3Al to γ-TiAl phase transformation was found in the temperature range of 600-770 °C. Based on the present work, the structural characteristics of TiAl powders are strongly dependent on their particle size, which should be considered in optimizing the process parameters of TiAl alloys fabricated from powders.

A Single Transcript CRISPR-Cas9 System for Multiplex Genome Editing in Plants.

The CRISPR-Cas9 system has been widely adopted in genome editing. By changing the 20 bp guide sequence, it can easily edit any sequence adjacent to a protospacer adjacent motif (PAM) in a genome. Multiplex genome editing could be accomplished with simultaneous expression of multiple single-guide RNAs (sgRNA). Given that sgRNAs are expressed by Pol III promoters, multiplex genome editing is conventionally done by assembly of multiple complete sgRNA expression cassettes together, which can be a challenge in vector construction. Here, we described a multiplex genome editing system based on a single transcript unit CRISPR-Cas9 (STU CRISPR-Cas9) expression system driven by a single Pol II promoter. It represents a novel approach for multiplex genome editing.

Single transcript unit CRISPR 2.0 systems for robust Cas9 and Cas12a mediated plant genome editing.

CRISPR-Cas9 and Cas12a are two powerful genome editing systems. Expression of CRISPR in plants is typically achieved with a mixed dual promoter system, in which Cas protein is expressed by a Pol II promoter and a guide RNA is expressed by a species-specific Pol III promoter such as U6 or U3. To achieve coordinated expression and compact vector packaging, it is desirable to express both CRISPR components under a single Pol II promoter. Previously, we demonstrated a first-generation single transcript unit (STU)-Cas9 system, STU-Cas9-RZ, which is based on hammerhead ribozyme for processing single guide RNAs (sgRNAs). In this study, we developed two new STU-Cas9 systems and one STU-Cas12a system for applications in plants, collectively called the STU CRISPR 2.0 systems. We demonstrated these systems for genome editing in rice with both transient expression and stable transgenesis. The two STU-Cas9 2.0 systems process the sgRNAs with Csy4 ribonuclease and endogenous tRNA processing system respectively. Both STU-Cas9-Csy4 and STU-Cas9-tRNA systems showed more robust genome editing efficiencies than our first-generation STU-Cas9-RZ system and the conventional mixed dual promoter system. We further applied the STU-Cas9-tRNA system to compare two C to T base editing systems based on rAPOBEC1 and PmCDA1 cytidine deaminases. The results suggest STU-based PmCDA1 base editor system is highly efficient in rice. The STU-Cas12a system, based on Cas12a' self-processing of a CRISPR RNA (crRNA) array, was also developed and demonstrated for expression of a single crRNA and four crRNAs. Altogether, our STU CRISPR 2.0 systems further expanded the CRISPR toolbox for plant genome editing and other applications.

A large-scale whole-genome sequencing analysis reveals highly specific genome editing by both Cas9 and Cpf1 (Cas12a) nucleases in rice.

BACKGROUND: Targeting specificity has been a barrier to applying genome editing systems in functional genomics, precise medicine and plant breeding. In plants, only limited studies have used whole-genome sequencing (WGS) to test off-target effects of Cas9. The cause of numerous discovered mutations is still controversial. Furthermore, WGS-based off-target analysis of Cpf1 (Cas12a) has not been reported in any higher organism to date. RESULTS: We conduct a WGS analysis of 34 plants edited by Cas9 and 15 plants edited by Cpf1 in T0 and T1 generations along with 20 diverse control plants in rice. The sequencing depths range from 45× to 105× with read mapping rates above 96%. Our results clearly show that most mutations in edited plants are created by the tissue culture process, which causes approximately 102 to 148 single nucleotide variations (SNVs) and approximately 32 to 83 insertions/deletions (indels) per plant. Among 12 Cas9 single guide RNAs (sgRNAs) and three Cpf1 CRISPR RNAs (crRNAs) assessed by WGS, only one Cas9 sgRNA resulted in off-target mutations in T0 lines at sites predicted by computer programs. Moreover, we cannot find evidence for bona fide off-target mutations due to continued expression of Cas9 or Cpf1 with guide RNAs in T1 generation. CONCLUSIONS: Our comprehensive and rigorous analysis of WGS data across multiple sample types suggests both Cas9 and Cpf1 nucleases are very specific in generating targeted DNA modifications and off-targeting can be avoided by designing guide RNAs with high specificity.

Longxuetongluo capsule inhibits atherosclerosis progression in high-fat diet-induced ApoE-/- mice by improving endothelial dysfunction.

BACKGROUND AND AIMS: Chinese dragon's blood has been used to treat blood stasis for thousands of years. Its total phenolic extract (Longxuetongluo capsule, LTC) is used for the treatment of ischemic stroke; however, its protective effect against atherosclerosis remains poorly understood. This paper aims to investigate the antiatherosclerotic effect of LTC and the underlying mechanisms in high-fat diet (HFD)-induced ApoE-/- mice. METHODS: The levels of plasma lipid and areas of atherosclerotic lesions in the aortic sinus in ApoE-/- mice were evaluated. The effect of LTC on the nitric oxide (NO) production in oxidized low-density lipoprotein (ox-LDL)-stimulated human umbilical vein endothelial cells (HUVECs) was determined. The adhesion of monocytes to ox-LDL-stimulated HUVECs was further studied. RESULTS: LTC at low, medium, and high doses markedly decreased the atherosclerotic lesion areas of the aortic sinus in HFD-induced ApoE-/- mice by 26.4% (p < 0.05), 30.1% (p < 0.05), and 46.5% (p < 0.01), respectively, although it did not improve the dyslipidemia. Furthermore, LTC restored the diminished NO production of ox-LDL-stimulated HUVECs (p < 0.001) and inhibited the adhesion between monocytes and endothelial cells (p < 0.01). LTC appeared to alleviate ox-LDL-stimulated dysfunction of HUVECs, and inhibit the adhesion of monocytes to HUVECs via the MAPK/IKK/IκB/NF-κB signaling pathway, thus decrease atherosclerotic lesions in the aortic sinus in HFD-induced ApoE-/- mice. CONCLUSIONS: These findings suggest the potential of LTC for use as an effective agent against atherosclerosis.

Longxuetongluo Capsule Improves Erythrocyte Function against Lipid Peroxidation and Abnormal Hemorheological Parameters in High Fat Diet-Induced ApoE-/- Mice.

Chinese dragon's blood, the red resin of Dracaena cochinchinensis, one of the renowned traditional medicines, has been used to facilitate blood circulation and disperse blood stasis for thousands of years. Phenolic compounds are considered to be responsible for its main biological activities. In this study, total phenolic compounds of Chinese dragon's blood were made into capsule (Longxuetongluo Capsule, LTC) and their effects on the abnormal hemorheological properties were examined by high fat diet (HFD) induced ApoE-/- mice. Compared to the model group, LTC recovered the abnormal hemorheological parameters in HFD-induced ApoE-/- mice by reducing whole blood viscosity (WBV) at high rate and improving erythrocyte function. In conclusion, LTC could ameliorate erythrocyte deformability and osmotic fragility through the reduction of lipid peroxidation on plasma and erythrocyte membranes in HFD-induced ApoE-/- mice, which supported the traditional uses of Chinese dragon's blood as an effective agent for improving blood microcirculation in hypercholesterolemia.

[Inhibitory effect of ilexpernoside C from Ilex pernyi on aggregated LDL-induced foam cells formation].

The aggregation of macrophage-derived foam cells on vascular wall is considered to be a main cause of atherosclerosis. In the present study, we evaluated the inhibitory effect of the compound ilexpernoside C (IC1) extracted from Ilex pernyi (Aquifoliaceae) on foam cell formation in THP-1 macrophages cells which were induced by low density lipoproteins aggregates (LDL aggregates). Results showed that IC1 could significantly inhibit the formation of foam cells. The analysis on related receptors of foam cells indicated that IC1 could significantly decrease the expression of low density lipoprotein-related receptor 1(LRP1). Therefore, these findings indicated that IC1 inhibited the formation of foam cells by inhibiting endocytosis of macrophages, thus it may act as a potential anti-atherosclerotic agent.

[Assessment of the results of syndrome in clinical trials of dementia treated by Chinese herbal medicine].

Chinese medical syndrome efficacy, as a second efficacy indicator, has been widely used in clinical trials of treating dementia by Chinese herbal medicine. The syndrome assessment tool is a key point in assessing the efficacy of Chinese medical syndrome. The syndrome assessment tool for dementia used nowadays needs to be optimized in content, reliability, and validity. In this paper, the authors reviewed some problems correlated with the design of Chinese medical assessment questionnaire on the basis of Chinese medical theories by combining the common requirements for questionnaire development.