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In order to study the effect of the rainfall infiltration on water migration in compacted loess, a model device was developed for testing water migration in the soil under rainfall conditions. In this study, the volumetric water content and resistivity of soil were introduced into the model test device. This model test device was applied to the study of water migration characteristics in compacted loess under different rainfall conditions. The results show that the resistivity decreases with the increase of the volumetric water content at the same depth of the loess column. In this way, the characteristics of the water migration can also be reflected from the change of the resistivity. There is an intimate relationship between the resistivity and volumetric water content, dry density. The volumetric water content and dry density are normalized by saturation of loess, arriving the equation of saturation against the resistivity. The characteristics of rainfall infiltration in compacted loess show a particular pattern, which demonstrates that, with the increase of dry density of the loess column, the rainfall infiltration line present “Y”, “D” and “Λ” shape distribution respectively, under light rain, heavy rain and rainstorm.

Heteroatom-doped carbon dots (CDs) have attracted extensive interest because of their improved electronic and fluorescence properties with heteroatom doping. In this study, a new synthetic method for nitrogen (N) and sulfur (S) -doped CDs was developed via a hydrothermal method using methionine and citric acid as raw materials. The as-prepared CDs exhibit excellent optical properties and good biocompatibility. The spherical N,S-doped CDs have an average diameter of 5 nm. They consist of C, O, N and S, and take on excellent water solubility due to the hydroxyl and carboxyl, amino groups on the surface. The CDs have a photoluminescence quantum yield of 13.8% using quinine sulfate as a reference; the average fluorescence lifetime of the CDs was 3.67 ns. The CDs solution present good photoluminescence properties, and the maximum excitation wavelength and emission wavelength locate at 330 nm and 405 nm, respectively. In addition, their fluorescence intensity almost does not change under the conditions of acid, alkali, and high salt, which indicated their anti-photobleaching property and good light stability. Based on the good biocompatibility and strong fluorescence emission of the CDs, they can be used as fluorescent imaging reagents.

The development of sensitive and specific methods for the high-quality analysis of hemin-related drugs is significant in the pharmaceutical field. In this work, a simple and rapid method based on the fluorescent properties of carbon dots (CDs) was established for the determination of hemin in drugs. By taking melamine and ethylenediamine as the reaction materials, the fluorescent CDs were synthesized by a one-step solvothermal method, which can be used for the determination of hemin in drugs by the fluorescent inner filter effect. The as-prepared fluorescent CDs with rich functional groups on the surface displayed good water solubility, strong salt resistance, robust pH stability, and photobleaching resistance. Most importantly, the fluorescent excitation wavelength of fluorescent CDs was very close to the absorption wavelength of hemin, providing the evidence for the fluorescent inner filter effect. When the hemin concentration was in the range of 0.01–1 μM, there was a good linear relationship between the hemin content with the fluorescence intensity of CDs. The linear regression equation was (1 − F/F0) = 0.0897c + 0.0124, with a correlation coefficient (R2) of 0.9982 and a detection limit of 9 nM. This assay was successfully used to determine the content of hemin in the tablet, which displayed 97.9–105.5% of the labelled amount, with a relative standard deviation of less than 3%. The developed fluorescence method for the detection of hemin content displays the advantages of accurate, rapid, and high sensitivity, which could prove to be a useful tool for the determination of hemin supplement tablets.

In order to study the effect of the rainfall infiltration on water migration in compacted loess, a model device was developed for testing water migration in the soil under rainfall conditions. In this study, the volumetric water content and resistivity of soil were introduced into the model test device. This model test device was applied to the study of water migration characteristics in compacted loess under different rainfall conditions. The results show that the resistivity decreases with the increase of the volumetric water content at the same depth of the loess column. In this way, the characteristics of the water migration can also be reflected from the change of the resistivity. There is an intimate relationship between the resistivity and volumetric water content, dry density. The volumetric water content and dry density are normalized by saturation of loess, arriving the equation of saturation against the resistivity. The characteristics of rainfall infiltration in compacted loess show a particular pattern, which demonstrates that, with the increase of dry density of the loess column, the rainfall infiltration line present \"Y\", \"D\" and \"Λ\" shape distribution respectively, under light rain, heavy rain and rainstorm.

Graphene possesses unique physical and chemical properties, which have inspired a wide range of potential biomedical applications. However, little is known about the adverse effects of graphene on the human body and ecological environment. The purpose of our work is to make assessment on the toxicity of graphene oxide （GO） against human cell line （human bone marrow neuroblastoma cell line and human epithelial carcinoma cell line） and zebrafish （Danio rerio） by comparing the toxic effects of GO with its sister, multi-walled carbon nanotubes （MWNTs）. The results show that GO has a moderate toxicity to organisms since it can induce minor （about 20%） cell growth inhibition and slight hatching delay of zebrafish embryos at a dosage of 50 mg/L, but did not result in significant increase of apoptosis in embryo, while MWNTs exhibit acute toxicity leading to a strong inhibition of cell proliferation and serious morphological defects in developing embryos even at relatively low concentration of 25 mg/L. The distinctive toxicity of GO and MWNTs should be ascribed to the different models of interaction between nanomaterials and organisms, which arises from the different geometric structures of nanomaterials. Collectively, our work suggests that GO does actual toxicity to organisms posing potential environmental risks and the result is also shedding light on the geometrical structure-dependent toxicity of graphitic nanomaterials.

The development of low-background, facile, and robust fluorescent nanoprobes for imaging and monitoring of intracellular mRNA changes remains a great challenge. Taking advantage of the high fluorescence quenching efficiency of core-shell gold@polydopamine (Au@PDA) nanocomposites and Ca2+-promoting DNA adsorption stability, a simple and universal bioconjugate strategy was designed to a construct fluorescent nanoprobe for highly efficient tumor-related mRNA imaging. The fluorescence of Cy5-labeled DNA was quenched up to 92.38% by the AuNP and PDA via nanometal surface energy transfer (NSET) and photoinduced electron transfer (PET), respectively. TK1 mRNA, a biomarker of tumor growth, initiates hybridization and results in fluorescence recovery, which built the foundation for identifying the expression level changes in living cells. More importantly, three kinds of tumor-related mRNA (TK1 mRNA, GalNAc-T mRNA, and C-myc mRNA) can be detected simultaneously with different fluorophore-modified recognition sequences, which can avoid false positive signals and improve the reliability of cancer diagnostic, holding great promise for cancer diagnosis, prognosis, and therapy.

Drought stress has been a severe challenge to world rice production. To elucidate the underlying mechanisms for rice drought adaptation, physiological characteristics, transcript expression patterns of related genes, and protein profiles from rice leaves were established for four rice cultivars with drastically different degrees of drought tolerance, and under drought stress, tolerant cultivars presented significantly reduced damage in growth and biomass retention. The loss in their main physiological characteristics was less than half of that in the sensitive varieties. Physiologically, the two tolerant varieties (303B and HY796) exhibited 30%–50% higher antioxidant enzyme activities, such as catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD), and a lower malondialdehyde (MDA) level, indicating effective cell membrane protection. Furthermore, there were also more strongly upregulated drought-responsive genes (such as OsDSM1 , OsCPK9 , and OsSNAC1 ) between the two varieties. A more tightly coordinated response was revealed at the protein level in the tolerant varieties via proteomic analysis. Carbohydrate metabolism, redox homeostasis, and protein transport were found to be activated in the tolerant varieties via functional enrichment analysis, while photosynthesis was suppressed. However, the networks of protein–protein interaction between more drought-tolerant lines were richer and well-connected. In the interaction networks of proteins, these two drought-tolerant lines had key hub proteins that play pivotal roles in effective signal transduction. The results systematically presented the complex regulatory network basis of drought resistance in rice and offered novel molecular targets for screening drought tolerance in rice.

Bacillus anthracis is a Gram-positive bacterium that can cause acute infection and anthracnose, which is a serious concern for human health. Determining Bacillus anthracis through its spore biomarker dipicolinic acid (DPA) is crucial, and there is a strong need for a method that is rapid, sensitive, and selective. Here, we created Eu(III)-coordination polymers (Eu-CPs) with surfaces that have abundant carboxyl and hydroxyl groups. This was achieved by using citric acid and europium nitrate hexahydrate as precursors in a straightforward one-pot hydrothermal process. These Eu-CPs were then successfully utilized for highly sensitive DPA determination. The fluorescence (FL) emission of Eu-CPs, which is typically weak due to the coordination of Eu(III) with water molecules, was significantly enhanced in the presence of DPA. This enhancement is attributed to the competitive binding between DPA’s carboxyl or hydroxyl groups and water molecules. As a result, the absorbed energy of DPA, when excited by 280 nm ultraviolet light, is transferred to Eu-CPs through an antenna effect. This leads to the emission of the characteristic red fluorescence of Eu3+ at 618 nm. A strong linear relationship was observed between the enhanced FL intensity and DPA concentration in the range of 0.5–80 μM. This relationship allowed for a limit of detection (LOD) of 15.23 nM. Furthermore, the Eu-CPs we constructed can effectively monitor the release of DPA from Bacillus subtilis spores, thereby further demonstrating the potential significance of this strategy in the monitoring and management of anthrax risk. This highlights the novelty of this approach in practical applications, provides a valuable determination technique for Bacillus anthracis, and offers insights into the development cycle of microorganisms.

As an important barrier between the cytoplasm and the microenvironment of the cell, the cell membrane is essential for the maintenance of normal cellular physiological activities. An abnormal cell membrane is a crucial symbol of body dysfunction and the occurrence of variant diseases; therefore, the visualization and monitoring of biomolecules associated with cell membranes and disease markers are of utmost importance in revealing the biological functions of cell membranes. Due to their biocompatibility, programmability, and modifiability, DNA nanomaterials have become increasingly popular in cell fluorescence imaging in recent years. In addition, DNA nanomaterials can be combined with the cell membrane in a specific manner to enable the real-time imaging of signal molecules on the cell membrane, allowing for the real-time monitoring of disease occurrence and progression. This article examines the recent application of DNA nanomaterials for fluorescence imaging on cell membranes. First, we present the conditions for imaging DNA nanomaterials in the cell membrane microenvironment, such as the ATP, pH, etc. Second, we summarize the imaging applications of cell membrane receptors and other molecules. Finally, some difficulties and challenges associated with DNA nanomaterials in the imaging of cell membranes are presented.

Inducing angiogenesis is a hallmark of cancers that sustains tumor growth and metastasis. Neovascularization is a surprisingly early event during the multistage progression of cancer. Cinobufagin, an important bufadienolide originating from Chan Su, has been clinically used to treat cancer in China since the Tang dynasty. Here, we show that cinobufagin suppresses colorectal cancer (CRC) growth in vivo by downregulating angiogenesis. The hierarchized neovasculature is significantly decreased and the vascular network formation is disrupted in HUVEC by cinobufagin in a dose‐dependent way. Endothelial apoptosis is observed by inducing reactive oxygen species (ROS) accumulation and mitochondrial dysfunction which can be neutralized by N‐acetyl‐l‐cysteine (NAC). Expression of hypoxia‐inducible factor 1α (HIF‐1α) is reduced and phosphorylation of mTOR at Ser2481 and Akt at Ser473 is downregulated in HUVEC. Endothelial apoptosis is triggered by cinobufagin by stimulation of Bax and cascade activation of caspase 9 and caspase 3. Increased endothelial apoptosis rate and alterations in the HIF‐1α/mTOR pathway are recapitulated in tumor‐bearing mice in vivo. Further, the anti‐angiogenesis function of cinobufagin is consolidated based on its pro‐apoptotic effects on an EOMA‐derived hemangioendothelioma model. In conclusion, cinobufagin suppresses tumor neovascularization by disrupting the endothelial mTOR/HIF‐1α pathway to trigger ROS‐mediated vascular endothelial cell apoptosis. Cinobufagin is a promising natural anti‐angiogenetic drug that has clinical translation potential and practical application value. Cinobufagin suppresses tumor neovascularization by disrupting the mTOR/HIF‐1α pathway to trigger ROS‐mediated vascular endothelial cell apoptosis. Cinobufagin is a promising natural anti‐angiogenetic drug that has clinical translation potential and practical application value.