High-temperature superconductivity in monolayer Bi2Sr2CaCu2O8+δ.

Although copper oxide high-temperature superconductors constitute a complex and diverse material family, they all share a layered lattice structure. This curious fact prompts the question of whether high-temperature superconductivity can exist in an isolated monolayer of copper oxide, and if so, whether the two-dimensional superconductivity and various related phenomena differ from those of their three-dimensional counterparts. The answers may provide insights into the role of dimensionality in high-temperature superconductivity. Here we develop a fabrication process that obtains intrinsic monolayer crystals of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi-2212; here, a monolayer refers to a half unit cell that contains two CuO2 planes). The highest superconducting transition temperature of the monolayer is as high as that of optimally doped bulk. The lack of dimensionality effect on the transition temperature defies expectations from the Mermin-Wagner theorem, in contrast to the much-reduced transition temperature in conventional two-dimensional superconductors such as NbSe2. The properties of monolayer Bi-2212 become extremely tunable; our survey of superconductivity, the pseudogap, charge order and the Mott state at various doping concentrations reveals that the phases are indistinguishable from those in the bulk. Monolayer Bi-2212 therefore displays all the fundamental physics of high-temperature superconductivity. Our results establish monolayer copper oxides as a platform for studying high-temperature superconductivity and other strongly correlated phenomena in two dimensions.

Methanol biotransformation toward high-level production of fatty acid derivatives by engineering the industrial yeast Pichia pastoris.

Methanol-based biorefinery is a promising strategy to achieve carbon neutrality goals by linking CO2 capture and solar energy storage. As a typical methylotroph, Pichia pastoris shows great potential in methanol biotransformation. However, challenges still remain in engineering methanol metabolism for chemical overproduction. Here, we present the global rewiring of the central metabolism for efficient production of free fatty acids (FFAs; 23.4 g/L) from methanol, with an enhanced supply of precursors and cofactors, as well as decreased accumulation of formaldehyde. Finally, metabolic transforming of the fatty acid cell factory enabled overproduction of fatty alcohols (2.0 g/L) from methanol. This study demonstrated that global metabolic rewiring released the great potential of P. pastoris for methanol biotransformation toward chemical overproduction.

Comparative physiology and transcriptome response patterns in cold-tolerant and cold-sensitive varieties of Solanum melongena.

BACKGROUND: Climate change has led to severe cold events, adversely impacting global crop production. Eggplant (Solanum melongena L.), a significant economic crop, is highly susceptible to cold damage, affecting both yield and quality. Unraveling the molecular mechanisms governing cold resistance, including the identification of key genes and comprehensive transcriptional regulatory pathways, is crucial for developing new varieties with enhanced tolerance. RESULTS: In this study, we conducted a comparative analysis of leaf physiological indices and transcriptome sequencing results. The orthogonal partial least squares discriminant analysis (OPLS-DA) highlighted peroxidase (POD) activity and soluble protein as crucial physiological indicators for both varieties. RNA-seq data analysis revealed that a total of 7024 and 6209 differentially expressed genes (DEGs) were identified from variety "A" and variety "B", respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment of DEGs demonstrated that the significant roles of starch and sucrose metabolism, glutathione metabolism, terpenoid synthesis, and energy metabolism (sucrose and starch metabolism) were the key pathways in eggplant. Weighted gene co-expression network analysis (WGCNA) shown that the enrichment of numerous cold-responsive genes, pathways, and soluble proteins in the MEgrep60 modules. Core hub genes identified in the co-expression network included POD, membrane transporter-related gene MDR1, abscisic acid-related genes, growth factor enrichment gene DELLA, core components of the biological clock PRR7, and five transcription factors. Among these, the core transcription factor MYB demonstrated co-expression with signal transduction, plant hormone, biosynthesis, and metabolism-related genes, suggesting a pivotal role in the cold response network. CONCLUSION: This study integrates physiological indicators and transcriptomics to unveil the molecular mechanisms responsible for the differences in cold tolerance between the eggplant cold-tolerant variety "A" and the cold-sensitive variety "B". These mechanisms include modulation of reactive oxygen species (ROS), elevation in osmotic carbohydrate and free proline content, and the expression of terpenoid synthesis genes. This comprehensive understanding contributes valuable insights into the molecular underpinnings of cold stress tolerance, ultimately aiding in the improvement of crop cold tolerance.

Engineering yeast for high-level production of ß-farnesene from sole methanol.

Methanol, a rich one-carbon feedstock, can be massively produced from CO2 by the liquid sunshine route, which is helpful to realize carbon neutrality. ß-Farnesene is widely used in the production of polymers, surfactants, lubricants, and also serves as a suitable substitute for jet fuel. Constructing an efficient cell factory is a feasible approach for ß-farnesene production through methanol biotransformation. Here, we extensively engineered the methylotrophic yeast Ogataea polymorpha for the efficient bio-production of ß-farnesene using methanol as the sole carbon source. Our study demonstrated that sufficient supply of precursor acetyl-CoA and cofactor NADPH in an excellent yeast chassis had a 1.3-fold higher ß-farnesene production than that of wild-type background strain. Further optimization of the mevalonate pathway and enhancement of acetyl-CoA supply led to a 7-fold increase in ß-farnesene accumulation, achieving the highest reported sesquiterpenoids production (14.7 g/L with a yield of 46 mg/g methanol) from one-carbon feedstock under fed-batch fermentation in bioreactor. This study demonstrates the great potential of engineering O. polymorpha for high-level terpenoid production from methanol.

Evaluation of vaccine candidates against Rhodococcus equi in BALB/c mice infection model: cellular and humoral immune responses.

Rhodococcus equi (R. equi) is a zoonotic opportunistic pathogen that mainly causes fatal lung and extrapulmonary abscesses in foals and immunocompromised individuals. To date, no commercial vaccine against R. equi exists. We previously screened all potential vaccine candidates from the complete genome of R. equi using a reverse vaccinology approach. Five of these candidates, namely ABC transporter substrate-binding protein (ABC transporter), penicillin-binding protein 2 (PBD2), NlpC/P60 family protein (NlpC/P60), esterase family protein (Esterase), and M23 family metallopeptidase (M23) were selected for the evaluation of immunogenicity and immunoprotective effects in BALB/c mice model challenged with R. equi. The results showed that all five vaccine candidate-immunized mice experienced a significant increase in spleen antigen-specific IFN-γ- and TNF-α-positive CD4 + and CD8 + T lymphocytes and generated robust Th1- and Th2-type immune responses and antibody responses. Two weeks after the R. equi challenge, immunization with the five vaccine candidates reduced the bacterial load in the lungs and improved the pathological damage to the lungs and livers compared with those in the control group. NlpC/P60, Esterase, and M23 were more effective than the ABC transporter and PBD2 in inducing protective immunity against R. equi challenge in mice. In addition, these vaccine candidates have the potential to induce T lymphocyte memory immune responses in mice. In summary, these antigens are effective candidates for the development of protective vaccines against R. equi. The R. equi antigen library has been expanded and provides new ideas for the development of multivalent vaccines.

All-optical polarization scrambler based on polarization beam splitting with an amplified fiber ring.

Optical-fiber-based polarization scramblers can reduce the impact of polarization sensitive performance of various optical fiber systems. Here, we propose a simple and efficient polarization scrambler based on an all-optical Mach-Zehnder structure by combining a polarization beam splitter and an amplified fiber ring. To totally decoherence one polarization split beam, a fiber ring together with an amplifier is incorporated. The ratio of two orthogonal beams can be controlled by varying the amplification factor, and we observe different evolution trajectories of the output state of polarizations on the Poincaré sphere. When the amplification factor exceeds a certain threshold, the scrambler system exhibits nearly ideal polarization scrambling behavior. A commercial single wavelength laser with a linewidth of 3 MHz is utilized to characterize the scrambling performance. We found that when the sampling rate is 1.6 MSa/s, a scrambling speed up to 2000krad/s can be obtained for the average degree of polarization being less than 0.1. We also exploit these random polarization fluctuations to generate random binary numbers, indicating that the proposed technique is a good candidate for a random bit generator.

Organo-organic interactions dominantly drive soil organic carbon accrual.

Organo-mineral interactions have been regarded as the primary mechanism for the stabilization of soil organic carbon (SOC) over decadal to millennial timescales, and the capacity for soil carbon (C) storage has commonly been assessed based on soil mineralogical attributes, particularly mineral surface availability. However, it remains contentious whether soil C sequestration is exclusively governed by mineral vacancies, making it challenging to accurately predict SOC dynamics. Here, through a 400-day incubation experiment using 13 C-labeled organic materials in two contrasting soils (i.e., Mollisol and Ultisol), we show that despite the unsaturation of mineral surfaces in both soils, the newly incorporated C predominantly adheres to "dirty" mineral surfaces coated with native organic matter (OM), demonstrating the crucial role of organo-organic interactions in exogenous C sequestration. Such interactions lead to multilayered C accumulation that is not constrained by mineral vacancies, a process distinct from direct organo-mineral contacts. The coverage of native OM by new C, representing the degree of organo-organic interactions, is noticeably larger in Ultisol (~14.2%) than in Mollisol (~5.8%), amounting to the net retention of exogenous C in Ultisol by 0.2-1.3 g kg-1 and in Mollisol by 0.1-1.0 g kg-1 . Additionally, organo-organic interactions are primarily mediated by polysaccharide-rich microbial necromass. Further evidence indicates that iron oxides can selectively preserve polysaccharide compounds, thereby promoting the organo-organic interactions. Overall, our findings provide direct empirical evidence for an overlooked but critically important pathway of C accumulation, challenging the prevailing "C saturation" concept that emphasizes the overriding role of mineral vacancies. It is estimated that, through organo-organic interactions, global Mollisols and Ultisols might sequester ~0.1-1.0 and ~0.3-1.7 Pg C per year, respectively, corresponding to the neutralization of ca. 0.5%-3.0% of soil C emissions or 5%-30% of fossil fuel combustion globally.

Protists regulate microbially mediated organic carbon turnover in soil aggregates.

Soil protists, the major predator of bacteria and fungi, shape the taxonomic and functional structure of soil microbiome via trophic regulation. However, how trophic interactions between protists and their prey influence microbially mediated soil organic carbon turnover remains largely unknown. Here, we investigated the protistan communities and microbial trophic interactions across different aggregates-size fractions in agricultural soil with long-term fertilization regimes. Our results showed that aggregate sizes significantly influenced the protistan community and microbial hierarchical interactions. Bacterivores were the predominant protistan functional group and were more abundant in macroaggregates and silt + clay than in microaggregates, while omnivores showed an opposite distribution pattern. Furthermore, partial least square path modeling revealed positive impacts of omnivores on the C-decomposition genes and soil organic matter (SOM) contents, while bacterivores displayed negative impacts. Microbial trophic interactions were intensive in macroaggregates and silt + clay but were restricted in microaggregates, as indicated by the intensity of protistan-bacterial associations and network complexity and connectivity. Cercozoan taxa were consistently identified as the keystone species in SOM degradation-related ecological clusters in macroaggregates and silt + clay, indicating the critical roles of protists in SOM degradation by regulating bacterial and fungal taxa. Chemical fertilization had a positive effect on soil C sequestration through suppressing SOM degradation-related ecological clusters in macroaggregate and silt + clay. Conversely, the associations between the trophic interactions and SOM contents were decoupled in microaggregates, suggesting limited microbial contributions to SOM turnovers. Our study demonstrates the importance of protists-driven trophic interactions on soil C cycling in agricultural ecosystems.

Trade-off between Pore-Throat Structure and Mineral Composition in Modulating the Stability of Soil Organic Carbon.

The preservation of soil organic carbon (OC) is an effective way to decelerate the emission of CO2 emission. However, the coregulation of pore structure and mineral composition in OC stabilization remains elusive. We employed the in situ nondestructive oxidation of OC by low-temperature ashing (LTA) combined with near edge X-ray absorption fine structure (NEXAFS), high-resolution microtomography (µ-CT), field emission electron probe microanalysis (FE-EPMA) with C-free embedding, and novel Cosine similarity measurement to investigate the C retention in different aggregate fractions of contrasting soils. Pore structure and minerals contributed equally (ca. 50%) to OC accumulation in macroaggregates, while chemical protection played a leading role in C retention with 53.4%-59.2% of residual C associated with minerals in microaggregates. Phyllosilicates were discovered to be more prominent than Fe (hydr)oxides in C stabilization. The proportion of phyllosilicates-associated C (52.0%-61.9%) was higher than that bound with Fe (hydr)oxides (45.6%-55.3%) in all aggregate fractions tested. This study disentangled quantitatively for the first time a trade-off between physical and chemical protection of OC varying with aggregate size and the different contributions of minerals to OC preservation. Incorporating pore structure and mineral composition into C modeling would optimize the C models and improve the soil C content prediction.

Synthesis and evaluation of L-quebrachitol derivatives against platelet aggregation.

Thrombosis plays an important role in the occurrence and development of cardiovascular and cerebrovascular diseases that contribute to high mortality and morbidity in patients. L-(-)-Quebrachitol (QCT), a natural product, was first isolated from quebracho bark. It can inhibit PAF receptor and decrease gastric damage induced by indomethacin, as a drug against platelet aggregation. Here, five QCT derivatives were synthesized and investigated for their inhibitory effects on platelet aggregation. Among them, compound 3a showed anticoagulant effects comparable to aspirin, while compound 4b showed dose-independent inhibitory activities in rats that were stronger than aspirin.

Identification and Molecular Characterization of the CAMTA Gene Family in Solanaceae with a Focus on the Expression Analysis of Eggplant Genes under Cold Stress.

Calmodulin-binding transcription activator (CAMTA) is an important calmodulin-binding protein with a conserved structure in eukaryotes which is widely involved in plant stress response, growth and development, hormone signal transduction, and other biological processes. Although CAMTA genes have been identified and characterized in many plant species, a systematic and comprehensive analysis of CAMTA genes in the Solanaceae genome is performed for the first time in this study. A total of 28 CAMTA genes were identified using bioinformatics tools, and the biochemical/physicochemical properties of these proteins were investigated. CAMTA genes were categorized into three major groups according to phylogenetic analysis. Tissue-expression profiles indicated divergent spatiotemporal expression patterns of SmCAMTAs. Furthermore, transcriptome analysis of SmCAMTA genes showed that exposure to cold induced differential expression of many eggplant CAMTA genes. Yeast two-hybrid and bimolecular fluorescent complementary assays suggested an interaction between SmCAMTA2 and SmERF1, promoting the transcription of the cold key factor SmCBF2, which may be an important mechanism for plant cold resistance. In summary, our results provide essential information for further functional research on Solanaceae family genes, and possibly other plant families, in the determination of the development of plants.

Low iron ameliorates the salinity-induced growth cessation of seminal roots in wheat seedlings.

Wheat plants are ubiquitously simultaneously exposed to salinity and limited iron availability caused by soil saline-alkalisation. Through this study, we found that both low Fe and NaCl severely inhibited the growth of seminal roots in wheat seedlings; however, sufficient Fe caused greater growth cessation of seminal roots than low Fe under salt stress. Low Fe improved the root meristematic division activity, not altering the mature cell sizes compared with sufficient Fe under salt stress. Foliar Fe spray and split-root experiments showed that low Fe-alleviating the salinity-induced growth cessation of seminal roots was dependent on local low Fe signals in the roots. Ionomics combined with TEM/X-ray few differences in the root Na+ uptake and vacuolar Na+ sequestration between two Fe levels under salt stress. Phytohormone profiling and metabolomics revealed salinity-induced overaccumulation of ACC/ethylene and tryptophan/auxin in the roots under sufficient Fe than under low Fe. Differential gene expression, pharmacological inhibitor addition and the root growth performance of transgenic wheat plants revealed that the rootward auxin efflux and was responsible for the low Fe-mediated amelioration of the salinity-induced growth cessation of seminal roots. Our findings will provide novel insights into the modulation of crop root growth under salt stress.

Microbial autotrophy explains large-scale soil CO2 fixation.

Microbial communities play critical roles in fixing carbon from the atmosphere and fixing it in the soils. However, the large-scale variations and drivers of these microbial communities remain poorly understood. Here, we conducted a large-scale survey across China and found that soil autotrophic organisms are critical for explaining CO2 fluxes from the atmosphere to soils. In particular, we showed that large-scale variations in CO2 fixation rates are highly correlated to those in autotrophic bacteria and phototrophic protists. Paddy soils, supporting a larger proportion of obligate bacterial and protist autotrophs, display four-fold of CO2 fixation rates over upland and forest soils. Precipitation and pH, together with key ecological clusters of autotrophic microbes, also played important roles in controlling CO2 fixation. Our work provides a novel quantification on the contribution of terrestrial autotrophic microbes to soil CO2 fixation processes at a large scale, with implications for global carbon regulation under climate change.

Thiol-ene chemistry incorporates a new spiropyran-containing polyurethane ionogel with photochromic, photomechanical and photoconductive properties.

The photocuring technology based on thiol-ene click reaction can be easily applied for copolymerizing or crosslinking the acrylate monomers for ionogels. However, there is still a problem: when the acrylate monomers contain the popular spiropyran as the stimuli-responsive group, it should be concerned about the participation of the active CC bond from the ring-opened spiropyran during a thiol-ene reaction, which may in turn affect the stimuli-responsiveness of the spiropyran. Up to now, the structure and properties of spiropyran-containing ionogels in this case have still not been well investigated. Therefore, in this work we carefully study a new spiropyran-containing polyurethane ionogel by crosslinking an acrylate-terminated, spiropyran-containing polyurethane prepolymer and a polythiol in ionic liquid through thiol-ene chemistry. It is found for the first time that, during constructing an ionogel, the coexistence of a reversible thiol-ene reaction between the CC bond from the ring-opened spiropyran and the thiol group can bring about a different reverse photochromic behavior. The proposed mechanism of the abnormal photochromism is analyzed. In addition, it is also observed that the thiol-ene chemistry can incorporate photomechanical and photoconductive properties into the new spiropyran-containing ionogel.

Dichotomous Role of Humic Substances in Modulating Transformation of Antibiotic Resistance Genes in Mineral Systems.

Widespread antibiotic resistance genes (ARGs) have emerged as a focus of attention for public health. Transformation is essential for ARGs dissemination in soils and associated environments; however, the mechanisms of how soil components contribute to the transformation of ARGs remain elusive. Here we demonstrate that three representative mineral-humic acid (HA) composites exert contrasting influence on the transformation of plasmid-borne ARGs in Bacillus subtilis. Mineral surface-bound HA facilitated transformation in kaolinite and montmorillonite systems, while an inhibitory effect of HA was observed for goethite. The elevated transformation by HA-coated kaolinite was mainly attributed to the enhanced activity of competence-stimulating factor (CSF), while increased transformation by montmorillonite-HA composites was assigned to the weakened adsorption affinity of DNA and enhanced gene expression induced by flagella-driven cell motility. In goethite system, HA played an overriding role in suppressing transformation via alleviation of cell membrane damage. The results obtained offer insights into the divergent mechanisms of humic substances in modulating bacterial transformation by soil minerals. Our findings would help for a better understanding on the fate of ARGs in soil systems and provide potentials for the utilization of soil components, particularly organic matter, to mitigate the spread of ARGs in a range of settings.

Recombination machinery engineering facilitates metabolic engineering of the industrial yeast Pichia pastoris.

The industrial yeast Pichia pastoris has been harnessed extensively for production of proteins, and it is attracting attention as a chassis cell factory for production of chemicals. However, the lack of synthetic biology tools makes it challenging in rewiring P. pastoris metabolism. We here extensively engineered the recombination machinery by establishing a CRISPR-Cas9 based genome editing platform, which improved the homologous recombination (HR) efficiency by more than 54 times, in particular, enhanced the simultaneously assembly of multiple fragments by 13.5 times. We also found that the key HR-relating gene RAD52 of P. pastoris was largely repressed in compared to that of Saccharomyces cerevisiae. This gene editing system enabled efficient seamless gene disruption, genome integration and multiple gene assembly with positive rates of 68-90%. With this efficient genome editing platform, we characterized 46 potential genome integration sites and 18 promoters at different growth conditions. This library of neutral sites and promoters enabled two-factorial regulation of gene expression and metabolic pathways and resulted in a 30-fold range of fatty alcohol production (12.6-380 mg/l). The expanding genetic toolbox will facilitate extensive rewiring of P. pastoris for chemical production, and also shed light on engineering of other non-conventional yeasts.

Clinical predictors of surgical intervention for gastrointestinal magnetic foreign bodies in children.

BACKGROUND/AIMS: To investigate the clinical situation, treatment methods, and clinical predictors of surgical intervention in children with magnetic foreign bodies in the digestive tract. MATERIALS AND METHODS: From January 2019 to June 2022, we retrospectively analyzed the clinical data of 72 children who ingested magnetic foreign bodies inadvertently in our hospital, including their general information, admissions, clinical manifestations, and treatment methods, as well as pertinent literature and statistical data. Following software processing, univariate and multivariate logistic regression analyses were conducted to determine the independent risk factors of this study. RESULTS: In this study, 16 patients (22.2%) were discharged smoothly following conservative treatment and 19 patients (26.4%) were cured by gastroscopy. The remaining 37 patients (51.4%) were underwent surgery, in which 26 cases developed gastrointestinal perforation. There were statistical differences between surgery group and non- surgery group in the days of eating by mistake, clinical manifestations (nausea and vomiting, intermittent abdominal pain, abdominal muscle tension) and movement trajectory by every 24-h radiograph (P < 0.01). Logistic regression analysis showed that intermittent abdominal pain and abdominal muscle tension were independent risk factors for surgical treatment. CONCLUSION: Magnetic foreign bodies seriously endanger children's health. This study offers a single-center basis for the choice of surgical opportunity for intestinal obstruction or perforation caused by magnetic foreign bodies. Clinicians need immediate surgical intervention if the child shows symptoms of abdominal pain or abdominal tension.

Direct experimental evidence of physical origin of electronic phase separation in manganites.

Electronic phase separation in complex oxides is the inhomogeneous spatial distribution of electronic phases, involving length scales much larger than those of structural defects or nonuniform distribution of chemical dopants. While experimental efforts focused on phase separation and established its correlation with nonlinear responses under external stimuli, it remains controversial whether phase separation requires quenched disorder for its realization. Early theory predicted that if perfectly "clean" samples could be grown, both phase separation and nonlinearities would be replaced by a bicritical-like phase diagram. Here, using a layer-by-layer superlattice growth technique we fabricate a fully chemically ordered "tricolor" manganite superlattice, and compare its properties with those of isovalent alloyed manganite films. Remarkably, the fully ordered manganite does not exhibit phase separation, while its presence is pronounced in the alloy. This suggests that chemical-doping-induced disorder is crucial to stabilize the potentially useful nonlinear responses of manganites, as theory predicted.

Elevated temperature induces contrasting transformation of exogenous copper to soil solution and solid phases in an arable soil.

Heavy metal contamination of soils has been a global environmental issue over the past decades, threatening food security and human health. Understanding the migration and transformation of heavy metals in soils is critical for restoring an impaired environment and developing sustainable agriculture, particularly in the face of global warming. However, little effort has been devoted to investigating the impact of elevated temperatures on the migration and distribution of exogenous heavy metals in soils. This study experimented with a 180-day incubation at 15 °C, 30 °C, and 45 °C with an arable soil (Alfisol) of Huang-Huai-Hai River Basin, China, which was initially spiked with copper (Cu). A comparison of the results revealed that the percentage of soil water-soluble Cu doubled at 45 °C compared with 15 °C. The percentage of protein-like substances in dissolved organic matter (DOM) was the highest at 45 °C, suggesting that proteinaceous components play a more significant role in controlling the dissolution of Cu into DOM. Moreover, by sequential extraction and micro-X-ray fluorescence (µ-XRF), Cu was facilitatively transformed from exchangeable, and specifically adsorbed fractions, to iron (Fe)/manganese (Mn) oxides bound species by 7.75%23.63% with the elevation of temperature from 15 °C to 45 °C. The conversion of Cu speciation is attributed to the significant release of organic carbon from Fe/Mn oxides, especially the Mn oxide components, which are available for Cu binding. The findings of this work will provide an in-depth understanding of the fate of Cu in soils, which is fundamental for the risk assessment and remediation of Cu-polluted soils in the Huang-Huai-Hai River Basin under the context of global warming.

[Diagnosis and treatment of four cases of asymptomatic and non-hydrous ureteral calculi].

This paper analyzed the clinical data, diagnosis and treatment of 4 asymptomatic patients with ureteral calculi without hydrops in our hospital from October 2018 to January 2019, and comprehensively discussed the previous literature. The 4 patients in this group had no obvious clinical symptoms, no positive stones were found in the B-ultrasound of the urinary system, and no hydroureter and hydroureter of the affected side was found. Urinary CT scan confirmed ureteral stones. They were all located in the lower ureter, and the stones obstructed the lumen. The stones were round and smooth, and there was no obvious hyperplasia and edema in the surrounding mucosa. The lithotripsy was completed in the first-stage operation, and the DJ catheter was left behind for one month after the operation. Based on the clinical diagnosis and treatment process of the 4 cases of asymptomatic calculi in this group and the analysis of previous studies, these patients were mostly detected by imaging examinations or other systematic imaging examinations during the regular review of urinary calculi. Ureteral stones with obstruction did not necessarily have stone-related symptoms. The onset of renal colic involved an increase in intraluminal pressure, related stimulation of nerve endings, smooth muscle spasms caused by stretching of the ureteral wall, and systemic changes in cytokines and related hormones. Cascade reactions, etc., were associated with the movement of stones down. Ureteral stones without hydrops were mostly located in the lower ureter, which had a certain buffering effect on obstructive pressure. Asymptomatic ureteral calculi could also induce irreversible damage to renal function, and the proportion of damage increased with the diameter of the stone. Patients with a history of urinary calculi, especially those with asymptomatic stones for the first time, should be paid attention to during clinical follow-up. At present, there are few research reports on asymptomatic and non-accumulating ureteral calculi. We analyze the clinical diagnosis and treatment process and characteristics of this group of patients combined with previous literature to provide a reference for the diagnosis and treatment of such patients.