Numerical study of Richtmyer-Meshkov instability in finite thickness fluid layers with reshock.

The evolution of a shock-induced fluid layer is numerically investigated in order to reveal the underlying mechanism of the Richtmyer-Meshkov instability under the effect of a reshock wave. Six different types of fluid layer are initially set up to study the effect of amplitude perturbation, fluid-layer thickness, and phase position on the reshocked fluid-layer evolution. Interface morphology results show that the interface-coupling effect gets strengthened when the fluid-layer thickness is small, which means the development of spikes and bubbles is inhibited to some extent compared to the case with large initial fluid-layer thickness. Two jets emerge on interface II_{1} under out-of-phase conditions, while bubbles are generated on interface II_{1} when the initial phase position is in-phase. The mixing width of the fluid layer experiences an early linear growth stage and a late nonlinear stage, between which the growth of the mixing width is considerably inhibited by the passage of the first and the second reshock and mildly weakened during phase reversion. The amplitude growth of interfaces agrees well with the theoretical model prediction, including both the linear and nonlinear stages. In the very late stage, the amplitude perturbation growth tends to differ from the theoretical prediction due to the squeezing effect and stretching effect.

Nanoscale Chemical Probing of Metal-Supported Ultrathin Ferrous Oxide via Tip-Enhanced Raman Spectroscopy and Scanning Tunneling Microscopy.

Metal-supported ultrathin ferrous oxide (FeO) has attracted immense interest in academia and industry due to its widespread applications in heterogeneous catalysis. However, chemical insight into the local structural characteristics of FeO, despite its critical importance in elucidating structure-property relationships, remains elusive. In this work, we report the nanoscale chemical probing of gold (Au)-supported ultrathin FeO via ultrahigh-vacuum tip-enhanced Raman spectroscopy (UHV-TERS) and scanning tunneling microscopy (STM). For comparative analysis, single-crystal Au(111) and Au(100) substrates are used to tune the interfacial properties of FeO. Although STM images show distinctly different moiré superstructures on FeO nanoislands on Au(111) and Au(100), TERS demonstrates the same chemical nature of FeO by comparable vibrational features. In addition, combined TERS and STM measurements identify a unique wrinkled FeO structure on Au(100), which is correlated to the reassembly of the intrinsic Au(100) surface reconstruction due to FeO deposition. Beyond revealing the morphologies of ultrathin FeO on Au substrates, our study provides a thorough understanding of the local interfacial properties and interactions of FeO on Au, which could shed light on the rational design of metal-supported FeO catalysts. Furthermore, this work demonstrates the promising utility of combined TERS and STM in chemically probing the structural properties of metal-supported ultrathin oxides on the nanoscale.

[Factors Influencing Willingness of Farmers to Pay for Agricultural Non-point Source Pollution Control Based on Distributed Cognitive Theory].

The analysis of the willingness of individual farmers to cover costs is an important basis for measuring the economic value of agricultural non-point pollution management， and determining the ecological and economic value of rural surface pollution control is a necessary measure to internalize the externalities of agricultural production. Based on the analysis of the hierarchy of factors influencing the cognition of farmers， this study constructed a theoretical framework based on distributed cognition theory to analyze their willingness to pay for agricultural non-point source pollution control from the perspective of individual farmers. On the basis of this framework， we used the Double-Hurdle model to empirically test the overall process of farmers'willingness to pay and their willingness to pay the amount for agricultural non-point source pollution control by combining 531 microscopic research datapoints in Guanzhong， Shaanxi Province. The results showed that： ① the number of farmers with willingness to pay for agricultural non-point source pollution control was 267， accounting for 50.30% of the total sample， and the average value of willingness to pay was 1 469.77 yuan·hm-2； the total economic value of agricultural non-point source pollution control in Shaanxi Province in 2020 was estimated to be 5.791 billion yuan based on the expected value of the willingness to pay level of the research sample. ② Farmers'willingness to pay for agricultural non-point source pollution control was influenced by the combined effects of personal， regional， and cultural forces， and the effects of each dimension were similar； farmers' willingness to pay for agricultural non-point source pollution control was mainly influenced by the cultural force factor， and the effects of personal and regional forces were very limited. ③ The results of the regressions by income level showed that personal and cultural strengths had a significant impact on the willingness to pay among the low-income group but did not contribute to the increase in the willingness to pay.

[Clinical characteristics and genetic analysis of two children with Tuberous sclerosis complex].

OBJECTIVE: To explore the clinical characteristics and genetic variants in two children with Tuberous sclerosis complex (TSC). METHODS: Two children who had presented at the Children's Hospital Affiliated to Zhengzhou University respectively in June 2020 and July 2021 were selected as the study subjects. Clinical data of the children were collected, and potential pathogenic variants were screened by whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing of their family members. RESULTS: Child 1 was a 7-month-and-29-day-old male, and child 2 was a 2-year-and-6-month-old male. Both children had shown symptoms of epileptic seizures and multiple hypomelanotic macules. Genetic testing revealed that both children had harbored de novo variants of the TSC2 gene, namely c.3239_3240insA and c.3330delC, which were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were rated as pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION: This study has uncovered the genetic etiology for two children with TSC. Above findings have also enriched the phenotypic and mutational spectrum of TSC in the Chinese population.

Can low-carbon cities increase urban housing prices? Evidence from China's low-carbon city pilot.

The low-carbon transformation is a broad and profound systemic change that will inevitably impact many areas of the urban environment, economy, and social system. We evaluated the impact of China's ongoing "low-carbon pilot policy" on urban housing prices as a "quasi-natural experiment." Existing research findings and hedonic theory predictions suggest that the low-carbon city pilot (LCCP) policy is increasing urban housing prices through air quality improvements. However, this study contradicts these speculations based on the situation in China. This study employed the analytical framework of staggered difference-in-differences (DID), which revealed that the LCCP policy had generally reduced housing prices; the implementation of the policy had led to an average decrease of 6.2% in housing prices in pilot cities, compared to non-pilot cities. The LCCP policy affected housing prices by influencing both the "demand side" and "supply side" of housing. In terms of the demand side, the policy significantly reduced the level of urban air pollution but did not impact housing prices. Instead, it negatively affected housing prices by lowering labor wages. In terms of the supply side, housing prices were negatively affected, mainly by increasing the cost of emission reduction of real estate enterprises, which impacted the original longstanding housing production process. Additionally, there were significant differences in the impact of the LCCP policy on housing prices in cities across different geographical locations and different tiers of cities. This study suggests important policy insights for achieving stable market housing prices and promoting high-quality urban development in the process of low-carbon transformation.

[Analysis of CLCN4 gene variant in a child with Raynaud-Claes syndrome].

OBJECTIVE: To analyze the clinical phenotype and genetic variant in a child with Raynaud-Claes syndrome (RCS). METHODS: A child who was diagnosed with RCS at the Children's Hospital Affiliated to Zhengzhou University for delayed language and motor development in August 2022 was selected as the study subject. Clinical data of the child were collected, and potential genetic variant was detected by next-generation sequencing and Sanger sequencing. The pathogenicity of the candidate variant was analyzed. RESULTS: The child, a 4-year-and-4-month-old male, has manifested global developmental delay, speech disorders, special facial features and behavioral abnormalities. Genetic testing revealed that he has harbored a hemizygous c.1174C>T (p.Gln392Ter) variant of the CLCN4 gene, which was not detected in either of his parents. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the variant was rated as pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION: The c.1174C>T (p.Gln392Ter) variant of the CLCN4 gene probably underlay the PCS in this child. Above finding has expanded the mutational spectrum of the CLCN4 gene and enabled genetic counseling and prenatal diagnosis for his family.

[Application of fluorescence in situ hybridization combined with chromosomal karyotyping analysis in children with disorders of sex development due to sex chromosome abnormalities].

OBJECTIVE: To retrospectively analyze sex chromosomal abnormalities and clinical manifestations of children with disorders of sex development (DSD). METHODS: A total of 14 857 children with clinical features of DSD including short stature, cryptorchidism, hypospadia, buried penis and developmental delay were recruited from Zhengzhou Children's Hospital from January 2013 to March 2022. Fluorescence in situ hybridization (FISH) and chromosomal karyotyping were carried out for such children. RESULTS: In total 423 children were found to harbor sex chromosome abnormalities, which has yielded a detection rate of 2.85%. There were 327 cases (77.30%) with Turner syndrome and a 45,X karyotype or its mosaicism. Among these, 325 were females with short stature as the main clinical manifestation, 2 were males with short stature, cryptorchidism and hypospadia as the main manifestations. Sixty-two children (14.66%) had a 47,XXY karyotype or its mosaicism, and showed characteristics of Klinefelter syndrome (KS) including cryptorchidism, buried penis and hypospadia. Nineteen cases (4.49%) had sex chromosome mosaicisms (XO/XY), which included 11 females with short stature, 8 males with hypospadia, and 6 cases with cryptorchidism, buried penis, testicular torsion and hypospadia. The remainder 15 cases (3.55%) included 9 children with a XYY karyotype or mosaicisms, with main clinical manifestations including cryptorchidisms and hypospadia, 4 children with a 47,XXX karyotype and clinical manifestations including short stature and labial adhesion, 1 child with a 46,XX/46,XY karyotype and clinical manifestations including micropenis, hypospadia, syndactyly and polydactyly, and 1 case with XXXX syndrome and clinical manifestations including growth retardation. CONCLUSION: Among children with DSD due to sex chromosomal abnormalities, sex chromosome characteristics consistent with Turner syndrome was most common, among which mosaicism (XO/XX) was the commonest. In terms of clinical manifestations, the females mainly featured short stature, while males mainly featured external genital abnormalities. Early diagnosis and treatment are particularly important for improving the quality of life in such children.

Atomic-Scale Insights into the Interlayer Characteristics and Oxygen Reactivity of Bilayer Borophene.

Bilayer (BL) two-dimensional boron (i.e., borophene) has recently been synthesized and computationally predicted to have promising physical properties for a variety of electronic and energy technologies. However, the fundamental chemical properties of BL borophene that form the foundation of practical applications remain unexplored. Here, we present atomic-level chemical characterization of BL borophene using ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS). UHV-TERS identifies the vibrational fingerprint of BL borophene with angstrom-scale spatial resolution. The observed Raman spectra are directly correlated with the vibrations of interlayer boron-boron bonds, validating the three-dimensional lattice geometry of BL borophene. By virtue of the single-bond sensitivity of UHV-TERS to oxygen adatoms, we demonstrate the enhanced chemical stability of BL borophene compared to its monolayer counterpart by exposure to controlled oxidizing atmospheres in UHV. In addition to providing fundamental chemical insight into BL borophene, this work establishes UHV-TERS as a powerful tool to probe interlayer bonding and surface reactivity of low-dimensional materials at the atomic scale.

Sodium butyrate reduces ammonia production in the cecum of laying hens by regulating ammonia-producing bacteria.

Sodium butyrate is a commonly used feed additive and can reduce ammonia (NH3) emissions from laying hens, but the mechanism of this effect is unknown. In this study, the sodium butyrate and cecal content of Lohmann pink laying hens were measured, and in vitro fermentation experiments and NH3-producing bacteria coculture experiments were carried out to explore the relationship between NH3 emissions and its associated microbiota metabolism. Sodium butyrate was found to significantly reduce NH3 emission from the cecal microbial fermentation of Lohmann pink laying hens (P < 0.05). The concentration of NO3--N in the fermentation broth of the sodium butyrate-supplemented group increased significantly, and the concentration of NH4+-N decreased significantly (P < 0.05). Moreover, sodium butyrate significantly reduced the abundance of harmful bacteria and increased the abundance of beneficial bacteria in the cecum. The culturable NH3-producing bacteria consisted mainly of Escherichia and Shigella, such as Escherichia fergusonii, Escherichia marmotae and Shigella flexnerii. Among them, E. fergusonii had the highest potential for NH3 production. The coculture experiment showed that sodium butyrate can significantly downregulate the expression of the lpdA, sdaA, gcvP, gcvH and gcvT genes of E. fergusonii (P < 0.05), thus reducing the NH3 emission produced by the bacteria during metabolism. In general, sodium butyrate regulated NH3-producing bacteria to reduce NH3 production in the cecum of laying hens. These results are of great significance for NH3 emission reduction in the layer breeding industry and for future research.

The fate of antibiotic resistance genes and their association with bacterial and archaeal communities during advanced treatment of pig farm wastewater.

Advanced wastewater treatment plants are widely used in most large-scale pig farms in southern China. However, the fate of antibiotic resistance genes (ARGs) and their association with bacterial and archaeal communities during advanced wastewater treatment remain unclear. In this study, the profiles of ARGs in typical advanced wastewater treatment plants were surveyed using metagenomic analysis. The results showed that 279- 326 different subtypes of ARGs were detected in raw wastewater, with a total abundance of 5.98 ± 0.48 copies per bacterial cell. During the advanced wastewater treatment, the abundance and number of ARGs were significantly reduced. Microbial communities (bacteria and archaea) contributed the most to the variation in ARG abundance and composition (PCA axis_1), accounting for 10.8 % and 15.7 %, respectively, followed by mobile genetic elements (MGEs) and physicochemical factors. Special attention should be given to potential pathogenic bacteria such as Escherichia, Streptococcus, Enterococcus and Staphylococcus and archaea such as Methanocorpusculum, Candidatus Methanoplasma and Candidatus Methanomethylophilus, which were important potential ARG hosts. Bacterial communities may indirectly affect ARG variation by affecting archaeal communities. These findings indicated that ARG levels in pig farm wastewater can be effectively reduced during advanced treatment and highlighted the important role played by archaea, which should not be ignored.

Organic Fertilizer Application Mediates Tomato Defense Against Pseudomonas syringae pv. Tomato, Possibly by Reshaping the Soil Microbiome.

Bacterial speck caused by Pseudomonas syringae pv. tomato is a serious foliar disease on tomato. However, it is still unknown how organic fertilizers application mediates plant defense against foliar pathogens by altering the composition of the soil microbial community. We conducted a 2-cycle pot experiment involving chemical and organic fertilizers and tracked tomato foliar pathogen incidence. Using microbiome sequencing, we then compared the differences in bulk and rhizosphere microbial communities. The results showed that, compared with soils amended with chemical fertilizer, soils amended with organic fertilizer gradually and significantly presented a reduction in tomato foliar disease, and the bacterial richness and diversity significantly increased. Moreover, the bacterial and fungal compositions of the bulk soil and rhizosphere soil of the organic fertilizer and chemical fertilizer treatments were different from each other. More importantly, the abundance of some potentially beneficial bacteria, such as Luteolibacter, Glycomyces, Flavobacterium, and Flavihumibacter, increased in the organic fertilizer-amended soil, and these genera were significantly negatively correlated with the incidence of tomato foliar disease. These results suggest that organic fertilizers can alter the taxonomy of the soil microbiome and that some specific beneficial microbial communities may play an important role in reducing the infection of foliar pathogens by inducing plant resistance.

Chemically identifying single adatoms with single-bond sensitivity during oxidation reactions of borophene.

The chemical interrogation of individual atomic adsorbates on a surface significantly contributes to understanding the atomic-scale processes behind on-surface reactions. However, it remains highly challenging for current imaging or spectroscopic methods to achieve such a high chemical spatial resolution. Here we show that single oxygen adatoms on a boron monolayer (i.e., borophene) can be identified and mapped via ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS) with ~4.8 Å spatial resolution and single bond (B-O) sensitivity. With this capability, we realize the atomically defined, chemically homogeneous, and thermally reversible oxidation of borophene via atomic oxygen in UHV. Furthermore, we reveal the propensity of borophene towards molecular oxygen activation at room temperature and phase-dependent chemical properties. In addition to offering atomic-level insights into the oxidation of borophene, this work demonstrates UHV-TERS as a powerful tool to probe the local chemistry of surface adsorbates in the atomic regime with widespread utilities in heterogeneous catalysis, on-surface molecular engineering, and low-dimensional materials.

Chemically imaging nanostructures formed by the covalent assembly of molecular building blocks on a surface with ultrahigh vacuum tip-enhanced Raman spectroscopy.

Surface-bound reactions have become a viable method to develop nanoarchitectures through bottom-up assembly with near atomic precision. However, the bottom-up fabrication of nanostructures on surfaces requires careful consideration of the intrinsic properties of the precursors and substrate as well as the complex interplay of any interactions that arise in the heterogeneous two-dimensional (2D) system. Therefore, it becomes necessary to consider these systems with characterization methods sensitive to such properties with suitable spatial resolution. Here, low temperature ultrahigh vacuum scanning tunneling microscopy (STM) and tip-enhanced Raman spectroscopy (TERS) were used to investigate the formation of 2D covalent networks via coupling reactions of tetra(4-bromophenyl)porphyrin (Br4TPP) molecules on a Ag(100) substrate. Through the combination of STM topographic imaging and TERS vibrational fingerprints, the conformation of molecular precursors on the substrate was understood. Following the thermally activated coupling reaction, STM and TERS imaging confirm the covalent nature of the 2D networks and suggest that the apparent disorder arises from molecular flexibility.

Controlling Localized Plasmons via an Atomistic Approach: Attainment of Site-Selective Activation inside a Single Molecule.

Chemical reactions such as bond dissociation and formation assisted by localized surface plasmons (LSPs) of noble metal nanostructures hold promise in solar-to-chemical energy conversion. However, the precise control of localized plasmons to activate a specific moiety of a molecule, in the presence of multiple chemically equivalent parts within a single molecule, is scarce due to the relatively large lateral distribution of the plasmonic field. Herein, we report the plasmon-assisted dissociation of a specific molecular site (C-Si bond) within a polyfunctional molecule adsorbed on a Cu(100) surface in the scanning tunneling microscope (STM) junction. The molecular site to be activated can be selected by carefully positioning the tip and bringing the tip extremely close to the molecule (atomistic approach), thereby achieving plasmonic nanoconfinement at the tip apex. Furthermore, multiple reactive sites are activated in a sequential manner at the sub-molecular scale, and different sets of products are created and visualized by STM topography and density functional theory (DFT) modeling. The illustration of site-selective activation achieved by localized surface plasmons implies the realization of molecular-scale resolution for bond-selected plasmon-induced chemistry.

Abundance, diversity and diffusion of antibiotic resistance genes in cat feces and dog feces.

The ARG profiles in pet feces, such as cat and dog feces, and their potential threat to environmental safety are still unclear. In this study, ARGs in 45 cat and 28 dog fecal samples were detected, and a diffusion experiment was performed to assess the risk of ARGs diffusion into the air. The results showed that the abundances of ARGs in cat feces and dog feces were high, and the abundance in dog feces (0.89 ± 0.17 copies/bacterial cell) was significantly higher than that in cat feces (0.46 ± 0.09 copies/bacterial cell) (P < 0.05). The bacterial community, especially Firmicutes and Desulfobacterota in cat feces, and Proteobacteria in dog feces, was the main factor affecting the variation in the ARG profiles, contributing to 31.6% and 32.4% of the variation in cat feces and dog feces, respectively. Physicochemical factors (especially NH4+-N) and age also indirectly affected the variation in the ARG profiles by affecting the bacterial community. In addition, the ARGs in cat feces and dog feces diffused into the air, but there was no evidence that this diffusion posed a threat to environmental safety and human health. These results can provide reference data for healthy animal breeding and the prevention and control of ARG pollution.

Angstrom-Scale Spectroscopic Visualization of Interfacial Interactions in an Organic/Borophene Vertical Heterostructure.

Two-dimensional boron monolayers (i.e., borophene) hold promise for a variety of energy, catalytic, and nanoelectronic device technologies due to the unique nature of boron-boron bonds. To realize its full potential, borophene needs to be seamlessly interfaced with other materials, thus motivating the atomic-scale characterization of borophene-based heterostructures. Here, we report the vertical integration of borophene with tetraphenyldibenzoperiflanthene (DBP) and measure the angstrom-scale interfacial interactions with ultrahigh-vacuum tip-enhanced Raman spectroscopy (UHV-TERS). In addition to identifying the vibrational signatures of adsorbed DBP, TERS reveals subtle ripples and compressive strains of the borophene lattice underneath the molecular layer. The induced interfacial strain is demonstrated to extend in borophene by ∼1 nm beyond the molecular region by virtue of 5 Šchemical spatial resolution. Molecular manipulation experiments prove the molecular origins of interfacial strain in addition to allowing atomic control of local strain with magnitudes as small as ∼0.6%. In addition to being the first realization of an organic/borophene vertical heterostructure, this study demonstrates that UHV-TERS is a powerful analytical tool to spectroscopically investigate buried and highly localized interfacial characteristics at the atomic scale, which can be applied to additional classes of heterostructured materials.

On-Surface Synthesis and Molecular Engineering of Carbon-Based Nanoarchitectures.

On-surface synthesis via covalent coupling of adsorbed precursor molecules on metal surfaces has emerged as a promising strategy for the design and fabrication of novel organic nanoarchitectures with unique properties and potential applications in nanoelectronics, optoelectronics, spintronics, catalysis, etc. Surface-chemistry-driven molecular engineering (i.e., bond cleavage, linkage, and rearrangement) by means of thermal activation, light irradiation, and tip manipulation plays critical roles in various on-surface synthetic processes, as exemplified by the work from the Ernst group in a prior issue of ACS Nano. In this Perspective, we highlight recent advances in and discuss the outlook for on-surface syntheses and molecular engineering of carbon-based nanoarchitectures.

CRISPR-Based Approaches for Efficient and Accurate Detection of SARS-CoV-2.

An outbreak of COVID-19, caused by infection with SARS-CoV-2 in Wuhan, China in December 2019, spread throughout the country and around the world, quickly. The primary detection technique for SARS-CoV-2, the reverse-transcription polymerase chain reaction (RT-PCR)-based approach, requires expensive reagents and equipment and skilled personnel. In addition, for SARS-CoV-2 detection, specimens are usually shipped to a designated laboratory for testing, which may extend the diagnosis and treatment time of patients with COVID-19. The latest research shows that clustered regularly interspaced short palindromic repeats (CRISPR)-based approaches can quickly provide visual, rapid, ultrasensitive, and specific detection of SARS-CoV-2 at isothermal conditions. Therefore, CRISPR-based approaches are expected to be developed as attractive alternatives to conventional RT-PCR methods for the efficient and accurate detection of SARS-CoV-2. Recent advances in the field of CRISPR-based biosensing technologies for SARS-CoV-2 detection and insights into their potential use in many applications are reviewed in this article.

All-in-one approaches for rapid and highly specific quantifcation of single nucleotide polymorphisms based on ligase detection reaction using molecular beacons as turn-on probes.

Rapid, simple, specific and sensitive approaches for single nucleotide polymorphisms (SNPs) detection are essential for clinical diagnosis. In this study, all-in-one approaches, consisting of the whole detection process including ligase detection reaction (LDR) and real time quantitative polymerase chain reaction performed in one PCR tube by a one-step operation on a real-time PCR system using molecular beacon (MB) as turn-on probe, were developed for rapid, simple, specific and sensitive quantifcation of SNPs. High specificity of the all-in-one approach was achieved by using the LDR, which employs a thermostable and single-base discerning Hifi Taq DNA ligase to ligate adjacently hybridized LDR-specific probes. In addition, a highly specific probe, MB, was used to detect the products of all-in-one approach, which doubly enhances the specificity of the all-in-one approach. The linear dynamic range and high sensitivity of mutant DNA (MutDNA) and wild-type DNA (WtDNA) all-in-one approaches for the detection of MutDNA and WtDNA were studied in vitro, with a broad linear dynamic range of 0.1 fM to 1 pM and detection limits of 65.3 aM and 31.2 aM, respectively. In addition, the MutDNA and WtDNA all-in-one approaches were able to accurately detect allele frequency changes as low as 0.1%. In particular, the epidermal growth factor receptor T790M MutDNA frequency in the tissue of five patients with non-small cell lung cancer detected by all-in-one approaches were in agreement with clinical detection results, indicating the excellent practicability of the developed approaches for the quantification of SNPs in real samples. In summary, the developed all-in-one approaches exhibited promising potential for further applications in clinical diagnosis.