Arising 2D Perovskites for Ionizing Radiation Detection.

2D perovskites have greatly improved moisture stability owing to the large organic cations embedded in the inorganic octahedral structure, which also suppresses the ions migration and reduces the dark current. The suppression of ions migration by 2D perovskites effectively suppresses excessive device noise and baseline drift and shows excellent potential in the direct X-ray detection field. In addition, 2D perovskites have gradually emerged with many unique properties, such as anisotropy, tunable bandgap, high photoluminescence quantum yield, and wide range exciton binding energy, which continuously promote the development of 2D perovskites in ionizing radiation detection. This review aims to systematically summarize the advances and progress of 2D halide perovskite semiconductor and scintillator ionizing radiation detectors, including reported alpha (α) particle, beta (ß) particle, neutron, X-ray, and gamma (γ) ray detection. The unique structural features of 2D perovskites and their advantages in X-ray detection are discussed. Development directions are also proposed to overcome the limitations of 2D halide perovskite radiation detectors.

Parameters optimization for decontamination and fine physical regeneration pathways of polypropylene plastics from waste lunchboxes.

Due to the development of the food delivery industry, a large amount of waste lunchboxes made of homo polypropylene (PP) plastic have been generated. This study developed a new technological strategy to effectively regenerate PP from waste lunchboxes. Through response surface curve analysis, it was found that under the optimal process conditions of hot alkali washing at 80 â„ƒ, 30 min, and pH 13, the optimal contact angle was 65.55°, indicating a good oil stain removal effect. By identifying and analyzing the characteristics of impurities in waste lunchboxes, a physical sorting and granulation regeneration process was constructed. And through large-scale statistical analysis and data collection, it was further verified that recycled PP plastics maintained their physical stability and excellent processing performance. The quality stability of recycled PP plastics in terms of impurities content was also verified. By designing different formulations specifically, recycled PP was mixed with different virgin PP and antioxidants in appropriate proportions, and extruded into particles under 150-300 mesh filtration conditions to obtain modified recycled PP. Modified recycled PP was applied in textiles, clothing, and injection molded products. In conclusion, we achieve the up-cylcing of waste PP lunchboxes instead of down-cylcing.

Quantifying evolution of soot mixing state from transboundary transport of biomass burning emissions.

Incomplete combustion of fossil fuels and biomass burning emit large amounts of soot particles into the troposphere. The condensation process is considered to influence the size (Dp) and mixing state of soot particles, which affects their solar absorption efficiency and lifetimes. However, quantifying aging evolution of soot remains hampered in the real world because of complicated sources and observation technologies. In the Himalayas, we isolated soot sourced from transboundary transport of biomass burning and revealed soot aging mechanisms through microscopic observations. Most of coated soot particles stabilized one soot core under Dp < 400 nm, but 34.8% of them contained multi-soot cores (nsoot ≥ 2) and nsoot increased 3-9 times with increasing Dp. We established the soot mixing models to quantify transformation from condensation- to coagulation-dominant regime at Dp ≈ 400 nm. Studies provide essential references for adopting mixing rules and quantifying the optical absorption of soot in atmospheric models.

Gibberellin signaling modulates flowering via the DELLA-BRAHMA-NF-YC module in Arabidopsis.

Gibberellin (GA) plays a key role in floral induction by activating the expression of floral integrator genes in plants, but the epigenetic regulatory mechanisms underlying this process remain unclear. Here, we show that BRAHMA (BRM), a core subunit of the chromatin-remodeling SWItch/sucrose nonfermentable (SWI/SNF) complex that functions in various biological processes by regulating gene expression, is involved in GA-signaling-mediated flowering via the formation of the DELLA-BRM-NF-YC module in Arabidopsis (Arabidopsis thaliana). DELLA, BRM, and NF-YC transcription factors interact with one another, and DELLA proteins promote the physical interaction between BRM and NF-YC proteins. This impairs the binding of NF-YCs to SOC1, a major floral integrator gene, to inhibit flowering. On the other hand, DELLA proteins also facilitate the binding of BRM to SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1). The GA-induced degradation of DELLA proteins disturbs the DELLA-BRM-NF-YC module, prevents BRM from inhibiting NF-YCs, and decreases the DNA-binding ability of BRM, which promote the deposition of H3K4me3 on SOC1 chromatin, leading to early flowering. Collectively, our findings show that BRM is a key epigenetic partner of DELLA proteins during the floral transition. Moreover, they provide molecular insights into how GA signaling coordinates an epigenetic factor with a transcription factor to regulate the expression of a flowering gene and flowering in plants.

Multiplex single-cell droplet PCR with machine learning for detection of high-risk human papillomaviruses.

High-risk human papillomavirus (HPV) testing can significantly decline the incidence and mortality of cervical cancer. Microfluidic technology provides an effective method for accurate detection of high-risk HPV by utilizing multiplex single-cell droplet polymerase chain reaction (PCR). However, current strategies are limited by low-integration microfluidic chip, complex reagent system, expensive detection equipment and time-consuming droplet identification. Here, we developed a novel multiplex droplet PCR method that directly detected high-risk HPV sequences in single cells. A multiplex microfluidic chip integrating four flow-focusing structures was designed for one-step and parallel droplet preparation. Using single-cell droplet PCR, multi-target sequences were detected simultaneously based on a monochromatic fluorescence signal. We applied machine learning to automatically identify the large populations of single-cell droplets with 97% accuracy. HPV16, 18 and 45 sequences were sensitively detected without cross-contamination in mixed CaSki and Hela cells. The approach enables rapid and reliable detection of multi-target sequences in single cells, making it powerful for investigating cellular heterogeneity related to cancer diagnosis and treatment.

Characterization of the complete mitochondrial genome of Cryptotermes domesticus (Blattodea: Kalotermitidae): Genome description and phylogenetic implications.

The complete mitochondrial genome of Cryptotermes domesticus (Haviland) was sequenced and annotated to study its characteristics and the phylogenetic relationship of C. domesticus to other termite species. The mitogenome of C. domesticus is a circular, close, and double-stranded molecule with a length of 15,655 bp. The sequenced mitogenome contains 37 typical genes, which are highly conserved in gene size, organization, and codon usage. Transfer RNA genes (tRNAs) also have typical secondary structures. All of the 13 protein-coding genes (PCGs) start with an ATN codon, except for nad4, which starts with GTG and terminates with the terminal codon TAA and TAG or the incomplete form T-- (cox2 and nad5). Most tRNAs have a typical cloverleaf structure, except for trnS1, in which this form is replaced by a simple loop and lacks the dihydrouridine (DHU) arm. The nucleotide diversity (Pi) and nonsynonymous (Ka)/synonymous (Ks) mutation rate ratios indicate that nad1, cox1, and cox3 are the most conserved genes, and that cox1 has the lowest rate of evolution. In addition, an 89 bp repeated sequence was found in the A + T-rich region. Phylogenetic analysis was performed using Bayesian inference (BI) and maximum likelihood (ML) methods based on 13 PCGs, and the monophyly of Kalotermitidae was supported.

Robust Underwater Oil-Repellent Biomimetic Ceramic Surfaces: Combining the Stability and Reproducibility of Functional Structures.

Robust underwater oil-repellent materials combining high mechanical strength and durability with superwettability and low oil adhesion are needed to build oil-repellent devices able to work in water, to manipulate droplet behavior, etc. However, combining all of these properties within a single, durable material remains a challenge. Herein, we fabricate a robust underwater oil-resistant material (Al2O3) with all of the above properties by gel casting. The micro/nanoceramic particles distributed on the surface endow the material with excellent underwater superoleophobicity (∼160°) and low oil adhesion (<4 µN). In addition, the substrate exhibits typical ceramic characteristics such as good antiacid/alkali properties, high salt resistance, and high load tolerance. These excellent properties make the material not only applicable to various liquid environments but also resistant to the impact of particles and other physical damage. More importantly, the substrate could still exhibit underwater superoleophobicity after being worn under specific conditions, as wear will create new surfaces with similar particle size distribution. This approach is easily scalable for mass production, which could open a pathway for the fabrication of practical underwater long-lasting functional interfacial materials.

Contrasting resistance of polycyclic aromatic hydrocarbons to atmospheric oxidation influenced by burning conditions.

The oxidation of polycyclic aromatic hydrocarbons (PAHs) determines their lifetime, toxicity and consequent environmental and climate impacts. The residential solid fuel burning composes of a substantial fraction of PAH emissions; however, their oxidation rate is yet to be explicitly understood, which is complicated by the contrasting emission factors under different combustion conditions and their subsequent evolution in the atmosphere. Here we used a plume evolution chamber using ambient oxidants to simulate the evolution of residential solid fuel burning emissions under real-world solar radiation, and then to investigate the oxidation process of the emitted PAHs. Contrasting oxidation rate of PAHs was found to be influenced by particles with or without presence of substantial amount of black carbon (BC). In the flaming burning phase, which contained 46% of BC mass fraction and 8% of organic aerosol (OA) internally mixed with BC, the larger PAHs (with 4-7 rings) was rapidly oxidized 12% for every hour of evolution under solar radiation; however, the larger PAHs from smoldering phase tended to maintain unmodified during the evolution, when 95% of OA was externally mixed with only minor fraction of BC (<5%). This may be ascribed to the complex morphology of BC, allowing more exposure for the internally-mixed OA to the oxidants; in contrast with those externally-mixed OA which was prone to be coated by condensed secondary substances. This raises an important consideration about the particle mixing state in influencing the oxidation of PAHs, particularly the coating on PAHs which may extend their lifetime and environmental impacts.

Evaluation of microplastic pollution in Shihezi city, China, using pine needles as a biological passive sampler.

Microplastic (MP) pollution has attracted much attention. To understand the characteristics of atmospheric MP pollution in Shihezi, Northwest China, this study used pine needles from trees in Shihezi City as passive samplers. MP contamination was found in all pine needle samples, with an average concentration of 16.52 ± 3.76 items/g. MPs were mainly in the shape of fragments (<0.05 mm). Differences in MP pollution were observed in different functional areas. The abundance of MPs in pine needles was the highest on the main traffic road (19.02 ± 2.52 items/g). Spectral analysis showed that the main polymer of MPs was polyethylene (17.2%), followed by polystyrene (15.5%) and polypropylene (13.8%). By analyzing the principal components and spatial distribution, fragments and pellets were found to have similar sources (mainly industrial activities), whereas films and fibers were influenced by traffic flow. The source of films was related to the packaging industry. The purpose of this study was to provide a reference for the future use of pine needles as atmospheric MP passive samplers, for the traceability and prevention of urban atmospheric MP pollution and for the formulation of national atmospheric MP environmental standards.

Vicariance and dispersal events inferred from mitochondrial genomes and nuclear genes (18S, 28S) shaped global Cryptocercus distributions.

Cryptocercus Scudder, a genus of wingless, subsocial cockroaches, has low vagility but exhibits a disjunct distribution in eastern and western North America, and in China, South Korea and the Russian Far East. This distribution provides an ideal model for testing hypotheses of vicariance through plate tectonics or other natural barriers versus dispersal across oceans or other natural barriers. We sequenced 45 samples of Cryptocercus to resolve phylogenetic relationships among members of the genus worldwide. We identified four types of tRNA rearrangements among samples from the Qin-Daba Mountains. Our maximum-likelihood and Bayesian phylogenetic trees, based on mitochondrial genomes and nuclear genes (18S, 28S), strongly supported six major lineages of Cryptocercus, which displayed a clear geographical distribution pattern. We used Bayesian molecular dating to estimate the evolutionary timescale of the genus, and reconstructed Cryptocercus ancestral ranges using statistical dispersal-vicariance analysis (S-DIVA) in RASP. Two dispersal events and six vicariance events for Cryptocercus were inferred with high support. The initial vicariance event occurred between American and Asian lineages at 80.5 Ma (95% credibility interval: 60.0-104.7 Ma), followed by one vicariance event within the American lineage 43.8 Ma (95% CI: 32.0-57.5 Ma), and two dispersal 31.9 Ma (95% CI: 25.8-39.5 Ma), 21.7 Ma (95% CI: 17.3-27.1 Ma) plus four vicariance events c. 29.3 Ma, 27.2 Ma, 24.8 Ma and 16.7 Ma within the Asian lineage. Our analyses provide evidence that both vicariance and dispersal have played important roles in shaping the distribution and diversity of these woodroaches.

Molecular characterization, expression and functional analysis of acyl-CoA-binding protein gene family in maize (Zea mays).

BACKGROUND: Acyl-CoA-binding proteins (ACBPs) possess a conserved acyl-CoA-binding (ACB) domain that facilitates binding to acyl-CoA esters and trafficking in eukaryotic cells. Although the various functions of ACBP have been characterized in several plant species, their structure, molecular evolution, expression profile, and function have not been fully elucidated in Zea mays L. RESULTS: Genome-wide analysis identified nine ZmACBP genes in Z. mays, which could be divided into four distinct classes (class I, class II, class III, and class IV) via construction of a phylogenetic tree that included 48 ACBP genes from six different plant species. Transient expression of a ZmACBP-GFP fusion protein in tobacco (Nicotiana tabacum) epidermal cells revealed that ZmACBPs localized to multiple different locations. Analyses of expression profiles revealed that ZmACBPs exhibited temporal and spatial expression changes during abiotic and biotic stresses. Eight of the nine ZmACBP genes were also found to have significant association with agronomic traits in a panel of 500 maize inbred lines. The heterologous constitutive expression of ZmACBP1 and ZmACBP3 in Arabidopsis enhanced the resistance of these plants to salinity and drought stress, possibly through alterations in the level of lipid metabolic and stress-responsive genes. CONCLUSION: The ACBP gene family was highly conserved across different plant species. ZmACBP genes had clear tissue and organ expression specificity and were responsive to both biotic and abiotic stresses, suggesting their roles in plant growth and stress resistance.

Variations in concentration and solubility of iron in atmospheric fine particles during the COVID-19 pandemic: An example from China.

Iron (Fe) in the atmosphere can affect atmospheric chemical processes and human health. When deposited into oceans, it can further influence phytoplankton growth. These roles of Fe fundamentally depend on its concentration and solubility. However, the sources of aerosol Fe and controlling factors of Fe solubility in megacities remain poorly understood. The outbreak of the COVID-19 pandemic causes large changes in human activities, which provides a unique opportunity to answer these key issues. Field observations were conducted before, during, and after the COVID-19 lockdown in Hangzhou, China. Our results show that in the COVID-19 lockdown stage, the concentrations of total Fe (FeT, 75.0 ng m-3) and soluble Fe (FeS, 5.1 ng m-3) in PM2.5 decreased by 78% and 62%, respectively, compared with those (FeT 344.7 ng m-3, FeS 13.5 ng m-3) in the pre-lockdown stage. The sharp reduction (81%) in on-road vehicles was most responsible for the aerosol Fe decrease. Surprisingly, the Fe solubility increased by a factor of 1.9, from 4.2% in the pre-lockdown stage to 7.8% in the COVID-19 lockdown stage. We found that the atmospheric oxidizing capacity was enhanced after lockdown restrictions were implemented, which promoted the formation of more acidic species and further enhanced the dissolution of aerosol Fe.

Evaluation of lensed fibers used in photodynamic therapy (PDT).

BACKGROUND: The combination of diode laser and lensed optical fiber is a commonly used technique in photodynamic therapy (PDT). The design of the lensed fiber can affect the beam quality, therefore, directly or indirectly effect treatment outcomes. In this study, several commercially available microlens and convex lens fibers used in PDT were evaluated. MATERIALS AND METHODS: A total of five types of lensed fibers were evaluated. The beam uniformity, expansion, and transmittance properties of lensed fibers to laser beams of 532 nm and 630 nm were analyzed. In addition, the spectral transmissions of lensed fibers were also examined using a broad band light source (400-1000 nm). RESULTS: Using microlens alone could significantly improve the light beam uniformity. The combination of lens and macrobendings could further improve the light beam uniformity. The beam expansion effect was determined by the numerical aperture (NA) of lens. The microlens fibers of higher NA showed better beam expansion effect than the convex lens of lower NA. The overall transmittance of tested lensed fibers ranged between 70 % and 77 %. CONCLUSIONS: Tested fibers showed good transmission property to the tested PDT wavelengths. Generally speaking, utilizing macrobending could improve the transmission quality of lens based frontal fiber-optic light distributors in PDT applications.

Upregulation of miRNA­301a­3p promotes tumor progression in gastric cancer by suppressing NKRF and activating NF­κB signaling.

MicroRNA­301a (miRNA/miR­301a) and nuclear factor (NF)­κB signaling play important roles in tumor invasion, migration and progression. However, the role of miRNA­301a­3p in human gastric cancer (GC), and specifically in the activation of NF­κB signaling, remains unclear. The aim of the present study was to investigate miRNA­301a­3p expression in GC progression and the molecular mechanisms as regards the regulation of NF­κB signaling. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was used to detect miRNA­301a­3p expression in GC and paired normal tissues. The association between the expression of miRNA­301a­3p and patient pathological parameters and the prognosis of GC was statistically analyzed using an in situ hybridization (ISH) assay. An MTS assay and a Transwell assay were performed to evaluate the effects of miRNA­301a­3p on the proliferation, invasion and migration of GC cells. RT­qPCR and western blot analysis were used to analyze the association between miRNA­301a­3p and nuclear factor­κB repressing factor (NKRF) expression and the corresponding downstream NF­κB signaling molecules. A luciferase assay was used to verify the target effect of miRNA­301a­3p and NKRF. It was found that miRNA­301a­3p expression was significantly higher in 30 cases of primary GC compared with matched normal tissues. Additionally, the ISH assay indicated that the high expression of miRNA­301a­3p in GC was associated with tumor invasion depth, lymph node metastasis, lymph node invasion and tumor metastasis stage. Patients whose tumors had a higher miRNA­301a­3p expression level exhibited a poorer prognosis. The in vitro assay indicated that miRNA­301a­3p affected the proliferative and invasive ability of GC cells by targeting the expression of NKRF, which then affected NF­κB signaling. Therefore, it was hypothesize that miRNA­301a­3p promotes GC progression and affects the prognosis of patients with GC by targeting NKRF, which in turn, directly influences NF­κB activation.

Iron solubility in fine particles associated with secondary acidic aerosols in east China.

Soluble iron (FeS) in aerosols contributes to free oxygen radical generation with implications for human health, and potentially catalyzes sulfur dioxide oxidation. It is also an important external source of micronutrients for ocean ecosystems. However, factors controlling FeS concentration and its contribution to total iron (FeT) in aerosols remain poorly understand. Here, FeS and FeT in PM2.5 was studied at four urban sites in eastern China from 21 to 31 December, 2017. Average FeT (869-1490 ng m-3) and FeS (24-68 ng m-3) concentrations were higher in northern than southern China cities, but Fe solubility (%FeS, 2.7-5.0%) showed no spatial pattern. Correlation analyses suggested %FeS was strongly correlated with FeS and PM2.5 instead of FeT concentrations. Individual particle observations confirmed that more than 65% of nano-sized Fe-containing particles were internally mixed with sulfates and nitrates. Furthermore, there was a high correlation between sulfates or nitrates/FeT molar ratio and %FeS. We also found that the sulfates/nitrates had weaker effects on %FeS at RH < 50% than at RH > 50%, suggesting RH as indirect factor can influence %FeS in PM2.5. These results suggest an important role of chemical processing in enhancing %FeS in the polluted atmosphere.

Volatile organic compounds in Shihezi, China, during the heating season: pollution characteristics, source apportionment, and health risk assessment.

From November 2018 to March 2019, the mixing ratios of 57 types of volatile organic compounds (VOCs) were measured using gas chromatography-mass spectrometry in Shihezi. The results depicted that the average mixing ratios of VOCs were 58.48 ppbv and alkanes (34.15 ppbv) showed the largest contribution, followed by ethyne (20.16 ppbv), alkenes (2.62 ppbv), and aromatics (1.55 ppbv). Based on the positive matrix factorization (PMF) model result, coal burning (39.83%), traffic-related exhaust (26.87%), liquefied petroleum gas/natural gas usage (LPG/NG) (17.32%), fuel evaporation and paint usage (9.02%), and industrial emission (6.96%) were distinguished. Secondary formation potential was applied to demonstrate the probability of secondary pollution; the results indicated that alkanes (27.30 ppbv) and alkenes (21.42 ppbv) played leading roles in ozone formation potential (OFP) and the contributions of alkanes (1.05 µg/m3) and aromatics (0.99 µg/m3) were nearly equal for secondary organic aerosol formation potential (SOAFP) under high-NOx condition. However, under a low-NOx condition, aromatics (2.12 µg/m3) dominated, and the contribution of alkanes (1.05 µg/m3) was lower. Monte Carlo simulation results showed that exposure to 1,3-butadiene and benzene may contribute potential carcinogenic risks to local residents; PMF results showed that reducing traffic-related and industrial emissions as well as coal burning was more effective in controlling carcinogenic risks. This study provides a crucial theoretical basis for decision-makers to minimize local air pollution more effectively.

Mixing State and Fractal Dimension of Soot Particles at a Remote Site in the Southeastern Tibetan Plateau.

The mixing state and fractal dimension (Df) of soot particles are two major factors affecting their absorption capacity and their climate effects. Here we investigated these factors of soot particles found in a typical valley of the southeastern Tibetan Plateau where wood burning in local villages was one major source of soot particles. Our motivation revealed Df and the aging property of soot particles in remote air and discussed their regional climatic implications. We found that 64% of total analyzed particles by number were soot-bearing particles and most of them aged with sulfate or organic coating. The Df sequence is bare-like soot (1.75 ± 0.08) < partly coated soot (1.82 ± 0.05) < embedded soot (1.88 ± 0.05). The aging process enlarged the overall size of the soot-bearing particles and increased the compactness of soot. Soot aging critically depended on high relative humidity (RH) during nighttime. Besides emission sources and coating processes, the coating aerosol phase under different RHs is another important factor affecting the soot Df.

Association of wheat chaff derived silica fiber and esophageal cancer in north China.

BACKGROUND: Despite decades of research and intervention programs, the epidemic of esophageal squamous cell carcinoma (ESCC) in the Taihang Mountain area of north China has not seen convincing explanation by any risk factor yet and the incidence has not seen a substantial decrease. Based on recently disclosed association of aridity and wheat consumption with esophageal cancer, we revisited the hypothesis of biogenic silica in esophageal cancer development. METHODS: From the archives of the Pathology Department of Heping Hospital, Changzhi Medical College, we selected three pairs of formalin-fixed samples, tumor tissues and distant normal tissues, of three patients operated for ESCC who had no history of workplace exposure to silica dust. Two pairs of dried tissue samples were used for phytolith (silica body) analysis and another pair for microanalysis with Transmission Electron Microscope (TEM). RESULTS: One of the phytoliths in ESCC tumor tissue was similar to the prickle hair on the surface of wheat bract. In the mineral particles detected in the tumor tissue the predominant elements were Si, Ca, and P, whereas Si signals were not obvious in the distant normal tissue. CONCLUSIONS: The preliminary findings on the detection of phytoliths and the higher than normal Si concentration in ESCC tumor tissue warrants further testing the role of biogenic silica in esophageal cancer.

Backscattering ratios of soot-contaminated dusts at triple LiDAR wavelengths: T-matrix results.

This paper reports on accurate calculations of backscattering properties of transported and soot-contaminated dust at triple wavelengths (0.355, 0.532, and 1.064 µm, respectively) by using the invariant imbedding T-matrix method. The changes of backscattering ratios from bare to soot-contaminated dust were systematically investigated by employing super-spheroidal dust and fractal soot models. The impacts of morphology change and soot absorptivity on backscattering ratios of soot-contaminated dust were clarified. In addition, it was found that adhesion has a large impact on the backscattering ratios. However, the results of non-contact soot-contaminated dust appear to be closer to observations than those of contact mixing.