Achieving Long-Lived Charge Separated State through Ultrafast Interfacial Hole Transfer in Redox Sites-Isolated CdS Nanorods for Enhanced Photocatalysis.

As opposed to natural photosynthesis, a significant challenge in a semiconductor-based photocatalyst is the limited hole extraction efficiency, which adversely affects solar-to-fuel efficiency. Recent studies have demonstrated that photocatalysts featuring spatially isolated dual catalytic oxidation/reduction sites can yield enhanced hole extraction efficiencies. However, the decay dynamics of excited states in such photocatalysts have not been explored. Here a ternary barbell-shaped CdS/MoS2/Cu2S heterostructure is prepared, comprising CdS nanorods (NRs) interfaced with MoS2 nanosheets at both ends and Cu2S nanoparticles on the sidewall. By using transient absorption (TA) spectra, highly efficient charge separation within the CdS/MoS2/Cu2S heterostructure are identified. This is achieved through directed electron transfer to the MoS2 tips at a rate constant of >8.3 × 109 s-1 and rapid hole transfer to the Cu2S nanoparticles on the sidewall at a rate of >6.1 × 1010 s-1, leading to an exceptional overall charge transfer constant of 2.3 × 1011 s-1 in CdS/MoS2/Cu2S. The enhanced hole transfer efficiency results in a remarkably prolonged charge-separated state, facilitating efficient electron accumulation within the MoS2 tips. Consequently, the ternary CdS/MoS2/Cu2S heterostructure demonstrates a 22-fold enhancement in visible-light-driven H2 generation compare to pure CdS nanorods. This work highlights the significance of efficient hole extraction in enhancing the solar-to-H2 performance of semiconductor-based heterostructure.

Coping with the liquidity crisis: a new dynamic quota readjustment scheme for carbon markets.

Because of insufficient liquidity, prices in the carbon market are more vulnerable to unexpected events, for which the impact duration lasts longer than that of the general market. The root reason for this phenomenon lies in the irrationality of quota distribution. The existing quota adjustment schemes and policies, e.g., the market stability reserve (MSR) and some recent adjustment measures, have poor timeliness and effectiveness, which has increased the risk of market crashes. Using the Hidden Markov Model (HMM), this paper develops a new dynamic quota adjustment scheme that can rapidly reduce the risk of quota supply by bridging quota price and quantity with price feedback as a response signal. To achieve this, we integrated the HMM algorithm and a two-step quota adjustment model by setting price thresholds and then connected the quota adjustment transition matrix and historical quota price. By comparing the MSR from 2013 to 2018, our scheme will help mitigate risks in quota price because the HMM can show the actual impact of price feedback on quota adjustment with merits of steady quota price and timely supply optimization. Moreover, our scheme, which recalculates the transition matrix, can be applied in other mature carbon markets.

The impact of COVID-19 on industry-related characteristics and risk contagion.

We use the cutting-edge causal forest algorithm to analyze the heterogeneous treatment effects of the COVID-19 outbreak on China's industry indexes. The variable importance index is used with the causal forest and complex network methods to analyze the characteristics of industrial relations and the types of industry risk contagion before and after the COVID-19 outbreak. The results show that the heterogeneity of industries was significantly weakened during the COVID-19 outbreak. In addition, the COVID-19 outbreak changed the original structure of the industry-related network, which shifted to a star network structure with leisure services at the core. It also changed the type of risk contagion between industries, from the original middleman risk type to the input risk type.

jaw-1D: a gain-of-function mutation responsive to paramutation-like induction of epigenetic silencing.

The Arabidopsis thaliana gain-of-function T-DNA insertion mutant jaw-1D produces miR319A, a microRNA that represses genes encoding CIN-like TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTORs (TCPs), a family of transcription factors that play key roles in leaf morphogenesis. In this study, we show that jaw-1D is responsive to paramutation-like epigenetic silencing. A genetic cross of jaw-1D with the polycomb gene mutant curly leaf-29 (clf-29) leads to attenuation of the jaw-1D mutant plant phenotype. This induced mutation, jaw-1D*, was associated with down-regulation of miR319A, was heritable independently from clf-29, and displayed paramutation-like non-Mendelian inheritance. Down-regulation of miR319A in jaw-1D* was linked to elevated levels of histone H3 lysine 9 dimethylation and DNA methylation at the CaMV35S enhancer located within the activation-tagging T-DNA of the jaw-1D locus. Examination of 21 independent T-DNA insertion mutant lines revealed that 11 could attenuate the jaw-1D mutant phenotype in a similar way to the paramutation induced by clf-29. These paramutagenic mutant lines shared the common feature that their T-DNA insertion was present as multi-copy tandem repeats and contained high levels of CG and CHG methylation. Our results provide important insights into paramutation-like epigenetic silencing, and caution against the use of jaw-1D in genetic interaction studies.

Photoacoustic microscopy in vivo using synthetic-aperture focusing technique combined with three-dimensional deconvolution.

Acoustic-resolution photoacoustic microscopy (ARPAM) plays an important role in studying the microcirculation system of biological tissues with deep penetration. High lateral resolution of ARPAM is achieved by using a high numerical aperture acoustic transducer. The deteriorated lateral resolution in the out-of-focus region can be alleviated by synthetic aperture focusing technique (SAFT). Previously, we reported a three-dimensional (3D) deconvolution ARPAM to improve both lateral and axial resolutions in the focus region. In this study, we present our extension of resolution enhancement to the out-of-focus region based on two-dimensional SAFT combined with the 3D deconvolution (SAFT+Deconv). In both the focus and out-of-focus regions, depth-independent lateral resolution provided by SAFT, together with inherently depth-independent axial resolution, ensures a depth-independent point spread function for 3D deconvolution algorithm. Imaging of 10 µm polymer beads shows that SAFT+Deconv ARPAM improves the -6 dB lateral resolutions from 65-700 µm to 20-29 µm, and the -6 dB axial resolutions from 35-42 µm to 12-19 µm in an extended depth of focus (DOF) of ∼2 mm. The signal-to-noise ratio is also increased by 6-30 dB. The resolution enhancement in three dimensions is validated by in vivo imaging of a mouse's dorsal subcutaneous microvasculature. Our results suggest that SAFT+Deconv ARPAM may allow fine spatial resolution with deep penetration and extended DOF for biomedical photoacoustic applications.

Synthetic aperture focusing technique for photoacoustic endoscopy.

Photoacoustic endoscopy (PAE) is a promising tool for the detection of atherosclerotic plaque. In this work, we propose a novel design of a side-viewing PAE probe based on a synthetic aperture focusing technique (SAFT) to enable high transverse resolution over large depth of focus (DOF) along the radial direction. A point-like ultrasonic detector is used to ensure a wide detection angle and thus a large synthetic aperture for SAFT. We first perform numerical simulation to optimize the PAE probe design, which involves the placement of the point-like detector and the diameter of a reflection rod mirror. Then, experiments are conducted based on the optimized probe design. High transverse resolution of 115-190 µm over large DOF of 3.5 mm along the radial direction is experimentally obtained. The SAFT-based PAE holds promise for endoscopic imaging with a high transverse resolution for both the surface and deep regions of tissue.

Transcription factors AS1 and AS2 interact with LHP1 to repress KNOX genes in Arabidopsis.

Polycomb group proteins are important repressors of numerous genes in higher eukaryotes. However, the mechanism by which Polycomb group proteins are recruited to specific genes is poorly understood. In Arabidopsis, LIKE HETEROCHROMATIN PROTEIN 1 (LHP1), also known as TERMINAL FLOWER 2, was originally proposed as a subunit of polycomb repressive complex 1 (PRC1) that could bind the tri-methylated lysine 27 of histone H3 (H3K27me3) established by the PRC2. In this work, we show that LHP1 mainly functions with PRC2 to establish H3K27me3, but not with PRC1 to catalyze monoubiquitination at lysine 119 of histone H2A. Our results show that complexes of the transcription factors ASYMMETRIC LEAVES 1 (AS1) and AS2 could help to establish the H3K27me3 modification at the chromatin regions of Class-I KNOTTED1-like homeobox (KNOX) genes BREVIPEDICELLUS and KNAT2 via direct interactions with LHP1. Additionally, our transcriptome analysis indicated that there are probably more common target genes of AS1 and LHP1 besides Class-I KNOX genes during leaf development in Arabidopsis.

Data-driven analysis of the simulations of the spread of COVID-19 under different interventions of China.

Since February 2020, COVID-19 has spread rapidly to more than 200 countries in the world. During the pandemic, local governments in China have implemented different interventions to efficiently control the spread of the epidemic. Characterizing transmission of COVID-19 under some typical interventions is essential to help countries develop appropriate interventions. Based on the pre-symptomatic transmission patterns of COVID-19, we established a novel compartmental model: Susceptible-Infectious-Confirmed-Removed (SICR) model, which allowed the effective reproduction number to change over time, thus the effects of policies could be reasonably estimated. Using the epidemic data of Wuhan, Wenzhou, and Shenzhen, we migrated the corresponding estimated policy modes to South Korea, Italy, and the United States and simulated the potential outcomes for these countries when they adopted similar policy strategies to China. We found that the mild interventions implemented in Shenzhen were effective in controlling the epidemic in the early stage, while more stringent policies which were implemented in Wuhan and Wenzhou were necessary if the epidemic became severe and needed to be controlled in a short time.

Risk factors associated with mortality of COVID-19 in 3125 counties of the United States.

BACKGROUND: The number of cumulative confirmed cases of COVID-19 in the United States has risen sharply since March 2020. A county health ranking and roadmaps program has been established to identify factors associated with disparity in mobility and mortality of COVID-19 in all counties in the United States. The risk factors associated with county-level mortality of COVID-19 with various levels of prevalence are not well understood. METHODS: Using the data obtained from the County Health Rankings and Roadmaps program, this study applied a negative binomial design to the county-level mortality counts of COVID-19 as of August 27, 2020 in the United States. In this design, the infected counties were categorized into three levels of infections using clustering analysis based on time-varying cumulative confirmed cases from March 1 to August 27, 2020. COVID-19 patients were not analyzed individually but were aggregated at the county-level, where the county-level deaths of COVID-19 confirmed by the local health agencies. Clustering analysis and Kruskal-Wallis tests were used in our statistical analysis. RESULTS: A total of 3125 infected counties were assigned into three classes corresponding to low, median, and high prevalence levels of infection. Several risk factors were significantly associated with the mortality counts of COVID-19, where higher level of air pollution (0.153, P < 0.001) increased the mortality in the low prevalence counties and elder individuals were more vulnerable in both the median (0.049, P < 0.001) and high (0.114, P < 0.001) prevalence counties. The segregation between non-Whites and Whites (low: 0.015, P < 0.001; median:0.025, P < 0.001; high: 0.019, P = 0.005) and higher Hispanic population (low and median: 0.020, P < 0.001; high: 0.014, P = 0.009) had higher likelihood of risk of the deaths in all infected counties. CONCLUSIONS: The mortality of COVID-19 depended on sex, race/ethnicity, and outdoor environment. The increasing awareness of the impact of these significant factors may help decision makers, the public health officials, and the general public better control the risk of pandemic, particularly in the reduction in the mortality of COVID-19.

Complexation of cyclohexanocucurbit[6]uril with cadmium ions: X-ray crystallographic and electrochemical study.

Complexation of cyclohexanocucurbit[6]uril (Q*[6]), a water-soluble cucurbit[n]uril derivative, with Cd(2+) ions has been studied by means of cyclic voltammetry and differential pulse voltammetry. The electrochemical experimental data prove the formation of a highly stable 1:6 Q*[6]/Cd(2+) complex. We also obtained the single-crystal X-ray structure of a cadmium ion complex with Q*[6], in which each portal of Q*[6] chelates three cadmium ions. The present study suggests the potential utility of Q*[6] as an effective cadmium ion chelator and extractant.

Dynamics of Soil Respiration in Alpine Wetland Meadows Exposed to Different Levels of Degradation in the Qinghai-Tibet Plateau, China.

The effects of degradation of alpine wetland meadow on soil respiration (Rs) and the sensitivity of Rs to temperature (Q10) were measured in the Napa Lake region of Shangri-La on the southeastern edge of the Qinghai-Tibet Plateau. Rs was measured for 24 h during each of three different stages of the growing season on four different degraded levels. The results showed: (1) peak Rs occurred at around 5:00 p.m., regardless of the degree of degradation and growing season stage, with the maximum Rs reaching 10.05 µmol·m-2·s-1 in non-degraded meadows rather than other meadows; (2) the daily mean Rs value was 7.14-7.86 µmol·m-2·s-1 during the mid growing season in non-degraded meadows, and declined by 48.4-62.6% when degradation increased to the severely degraded level; (3) Q10 ranged from 7.1-11.3 in non-degraded meadows during the mid growing season, 5.5-8.0 and 6.2-8.2 during the early and late growing seasons, respectively, and show a decline of about 50% from the non-degraded meadows to severely degraded meadows; (4) Rs was correlated significantly with soil temperature at a depth of 0-5 cm (p < 0.05) on the diurnal scale, but not at the seasonal scale; (5) significant correlations were found between Rs and soil organic carbon (SOC), between biomass and SOC, and between Q10 and Rs (p < 0.05), which indicates that biomass and SOC potentially impact Q10. The results suggest that vegetation degradation impact both Rs and Q10 significantly. Also, we speculated that Q10 of alpine wetland meadow is probable greater at the boundary region than inner region of the Qinghai-Tibet Plateau, and shoule be a more sensitive indicator in the studying of climate change in this zone.

In vivo deconvolution acoustic-resolution photoacoustic microscopy in three dimensions.

Acoustic-resolution photoacoustic microscopy (ARPAM) provides a spatial resolution on the order of tens of micrometers, and is becoming an essential tool for imaging fine structures, such as the subcutaneous microvasculature. High lateral resolution of ARPAM is achieved using high numerical aperture (NA) of acoustic transducer; however, the depth of focus and working distance will be deteriorated correspondingly, thus sacrificing the imaging range and accessible depth. The axial resolution of ARPAM is limited by the transducer's bandwidth. In this work, we develop deconvolution ARPAM (D-ARPAM) in three dimensions that can improve the lateral resolution by 1.8 and 3.7 times and the axial resolution by 1.7 and 2.7 times, depending on the adopted criteria, using a 20-MHz focused transducer without physically increasing its NA and bandwidth. The resolution enhancement in three dimensions by D-ARPAM is also demonstrated by in vivo imaging of the microvasculature of a chick embryo. The proposed D-ARPAM has potential for biomedical imaging that simultaneously requires high spatial resolution, extended imaging range, and long accessible depth.