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2.
Rev Sci Instrum ; 95(8)2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-39120445

RESUMEN

State-of-the-art optical cavities are pivotal in pushing the envelope of laser frequency stability below 10-16. This is often achieved by extending the cavity length or cooling the system to cryogenic temperatures to reduce the thermal noise floor. In our study, we present a 30-cm-long cavity that operates at room temperature and is outfitted with crystalline coatings. The system has a predicted ultralow thermal noise floor of 4.4 × 10-17, comparable to what is observed in cryogenic silicon cavities. A 1397-nm laser is stabilized in this advanced cavity, and the stable frequency is then transferred to the clock transition in strontium optical lattice clocks via a frequency-doubling process. We have meticulously minimized and assessed the technical noise contributions through comparisons with an ultrastable reference laser that is locked to a commercially available 30-cm cavity. The frequency instability of the system is rigorously evaluated using a three-cornered-hat method. The results demonstrate that the laser frequency instability remains below 2 × 10-16 for averaging times ranging from 1 to 50 s. These findings underscore the significant potential of room-temperature cavities with crystalline coatings in high-precision metrology and pave the way for further improvements in optical lattice clocks.

3.
Front Plant Sci ; 15: 1419876, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39211841

RESUMEN

The Shandong Peninsula, the largest peninsula in China, is situated at the estuary of the Yellow River and is bordered by both the Bohai Sea and the Yellow Sea. This region is renowned for its rich plant diversity. However, the historical origins of these plant species remain poorly understood. This study analyzed 2410 shared species from 865 genera and 161 families distributed across Shandong and its nine adjacent regions to investigate the floristic diversity of the Shandong Peninsula. These regions were considered as operational taxonomic units (OTUs), with the shared species serving as the basis for each OTU. Hierarchical cluster analyses were performed to assess their floristic similarity, employing the Bray-Curtis distance algorithm and the UPGMA clustering method. The results revealed that the ten regions were grouped into three clusters, delineated by the Yellow River. Notably, the floristic similarity of the Shandong Peninsula was found to be more closely aligned with regions south of the Yellow River, despite Shandong historical connection to Liaoning in the north. These findings underscore the barrier effect of the Yellow River and provide insights into the formation of biotic diversity patterns between northern and eastern China.

4.
Environ Sci Technol ; 58(31): 13961-13972, 2024 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-39037720

RESUMEN

Earthworms are critical in regulating soil processes and act as filters for antibiotic resistance genes (ARGs). Yet, the geographic patterns and main drivers of earthworm gut ARGs remain largely unknown. We collected 52 earthworm and soil samples from arable and forest ecosystems along a 3000 km transect across China, analyzing the diversity and abundance of ARGs using shotgun metagenomics. Earthworm guts harbored a lower diversity and abundance of ARGs compared to soil, resulting in a stronger distance-decay rate of ARGs in the gut. Greater deterministic assembly processes of ARGs were found in the gut than in soil. The earthworm gut had a lower frequency of co-occurrence patterns between ARGs and mobile genetic elements (MGEs) in forest than in arable systems. Viral diversity was higher in the gut compared to soil and was negatively correlated with bacterial diversity. Bacteria such as Streptomyces and Pseudomonas were potential hosts of both viruses and ARGs. Viruses had negative effects on the diversity and abundance of ARGs, likely due to the lysis on ARG-bearing bacteria. These findings provide new insights into the variations of ARGs in the earthworm gut and highlight the vital role of viruses in the regulation of ARGs in the soil ecosystem.


Asunto(s)
Oligoquetos , Microbiología del Suelo , Animales , Farmacorresistencia Microbiana/genética , Bacterias/efectos de los fármacos , Bacterias/genética , Antibacterianos/farmacología , Suelo , China , Metagenómica
6.
Rev Sci Instrum ; 95(4)2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38564326

RESUMEN

Optical thin films with high-reflectivity (HR) are essential for applications in quantum precision measurements. In this work, we propose a coating technique based on reactive magnetron sputtering with RF-induced substrate bias to fabricate HR-optical thin films. First, atomically flat SiO2 and Ta2O5 layers have been demonstrated due to the assistance of radio-frequency plasma during the coating process. Second, a distributed Bragg reflector (DBR) mirror with an HR of ∼99.999 328% centered at 1397 nm has been realized. The DBR structure is air-H{LH}19-substrate, in which the L and H denote a single layer of SiO2 with a thickness of 237.8 nm and a single layer of Ta2O5 with a thickness of 171.6 nm, respectively. This novel coating method would facilitate the development of HR reflectors and promote their wide applications in precision measurements.

7.
Ying Yong Sheng Tai Xue Bao ; 35(2): 447-456, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38523103

RESUMEN

We conducted a field experiment in the dry farming area in south Ningxia from 2018 to 2021, to explore the influence of tillage methods combined with mulching on soil bulk density, aggregate content, soil water storage and potato yield under different precipitation years. There were four tillage methods (15 cm depth ploughing, and 30 cm, 40 cm and 50 cm depth subsoiling) and three mulching measures (mulching with oat straw, plastic film and no mulching), with the ploughing depth of 15 cm without mulching as control. The results showed the combination of tillage and mulching effectively reduced soil bulk density in 0-60 cm layer after three years of farming compared with that prior to the experiment. Under the same tillage mode, the best effect was achieved in mulching with oat straw under different precipitation years. To be specific, the best effect in 20 cm and 40 cm soil layers was achieved in mulching with oat straw for 30 cm depth subsoiling, in 60 cm soil layer for 15 cm ploughing in wet year, and for 40 cm depth subsoiling in 20 cm, 40 cm and 60 cm soil layers in normal and dry years. In 0-20 cm soil layer, the content of >0.25 mm soil aggregate was the highest for 40 cm depth subsoiling with oat straw mul-ching in all the three years. In 20-40 cm soil layer, the content was the highest for 15 cm depth ploughing with oat straw mulching in wet year, and for 40 cm depth subsoiling with oat straw mulching in normal and dry years. In 40-60 cm soil layer, content was the highest for 15 cm depth ploughing with plastic film mulching, 30 cm depth subsoiling with plastic film mulching, and 30 cm depth subsoiling with oat straw mulching in wet, normal and dry years, which was increased by 18.8%, 27.0%, and 35.8%, respectively, compared with the control. In the key growth stage (from squaring to tuber expansion) of potatoes, soil water storage in 0-100 cm layer was optimal for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling with oat straw mulching in normal and dry years, with an increase of 19.4%, 19.5%, and 23.7%, respectively. Potato yield was the highest for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling in normal and dry years, with an increase of 84.6%, 81.7%, and 106.3%, respectively. The correlation analysis showed that improved soil physical properties played a significant role in increasing potato yield, with the most significant role of soil bulk density and soil water storage at the squaring stage. Potato yield was high at a tillage depth of 34.67-36.03 cm. We concluded that the combination of tillage method and mulching could effectively improve soil physical pro-perties and increase soil water storage in the growth stage of potatoes, thereby significantly increa-sing potato yield. Potato yield in dry farming area could be enhanced through 30 cm depth subsoiling with oat straw mulching in wet years, and 40 cm depth subsoiling with oat straw mulching in normal and dry years.


Asunto(s)
Suelo , Solanum tuberosum , Agricultura/métodos , Granjas , Agua , China , Zea mays
8.
Biotechnol Biofuels Bioprod ; 17(1): 44, 2024 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-38500189

RESUMEN

2,5-Dimethylpyrazine (2,5-DMP) is important pharmaceutical raw material and food flavoring agent. Recently, engineering microbes to produce 2,5-DMP has become an attractive alternative to chemical synthesis approach. In this study, metabolic engineering strategies were used to optimize the modified Escherichia coli BL21 (DE3) strain for efficient synthesis of 2,5-DMP using L-threonine dehydrogenase (EcTDH) from Escherichia coli BL21, NADH oxidase (EhNOX) from Enterococcus hirae, aminoacetone oxidase (ScAAO) from Streptococcus cristatus and L-threonine transporter protein (EcSstT) from Escherichia coli BL21, respectively. We further optimized the reaction conditions for synthesizing 2,5-DMP. In optimized conditions, the modified strain can convert L-threonine to obtain 2,5-DMP with a yield of 2897.30 mg/L. Therefore, the strategies used in this study contribute to the development of high-level cell factories for 2,5-DMP.

9.
Nat Commun ; 15(1): 453, 2024 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-38212316

RESUMEN

With the rapid development of nuclear energy, problems with uranium supply chain and nuclear waste accumulation have motivated researchers to improve uranium separation methods. Here we show a paradigm for such goal based on the in-situ formation of π-f conjugated two-dimensional uranium-organic framework. After screening five π-conjugated organic ligands, we find that 1,3,5-triformylphloroglucinol would be the best one to construct uranium-organic framework, thus resulting in 100% uranium removal from both high and low concentration with the residual concentration far below the WHO drinking water standard (15 ppb), and 97% uranium capture from natural seawater (3.3 ppb) with a record uptake efficiency of 0.64 mg·g-1·d-1. We also find that 1,3,5-triformylphloroglucinol can overcome the ion-interference issue such as the presence of massive interference ions or a 21-ions mixed solution. Our finds confirm the superiority of our separation approach over established ones, and will provide a fundamental molecule design for separation upon metal-organic framework chemistry.

10.
Asian J Surg ; 47(1): 310-319, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37673742

RESUMEN

BACKGROUND: Immune-related scores are currently used for prognostic evaluation and as an immunotherapy reference in various cancers. However, the relationship between immune-related score and hepatocellular carcinoma (HCC) prognosis has not yet been investigated. This study aimed to explore the clinical application value of immune-related score for predicting HCC prognosis-related indicators including disease-free survival (DFS) and overall survival (OS), and to construct a clinical nomogram prediction model related to verification. METHODS: This study included 284 HCC patients who were selected from the Cancer Genome Atlas (TCGA) database and linked to the immune-related score downloaded from the public platform. A Cox proportional hazards regression model was used to estimate the adjusted risk ratio, and a nomogram was constructed based on multivariate analysis results and clinical significance. The model was internally verified by bootstrap. The performance of the prediction model was evaluated using the C-index and calibration curves. RESULTS: Patients were divided into three subgroups according to the immune-related score level. Compared with patients in the low immune-related score group, the DFS of patients in the medium and high immune-related score groups was significantly prolonged (HR: 0.53, 95% CI: 0.32-0.87; HR: 0.37, 95% CI: 0.21-0.63, respectively). The OS of patients in the medium and high immune-related score groups was also significantly prolonged (HR: 0.43, 95% CI: 0.20-0.95, p = 0.038; HR: 0.29, 95% CI: 0.14-0.58, p < 0.001, respectively). The C-indexes for predicting DFS and OS were 0.687 (95% CI: 0.665-0.700) and 0.743 (95% CI: 0.709-0.776), respectively. The calibration curves of 3-year and 5-year DFS and OS showed that the results predicted by the nomogram were in good agreement with the actual observations. CONCLUSIONS: Moderate/high-grade immune-related score was significantly associated with better DFS and OS in HCC patients. In addition, a nomogram for prognosis estimation can help clinicians predict the survival status of patients.


Asunto(s)
Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Pronóstico , Nomogramas , Supervivencia sin Enfermedad
11.
Ann Hematol ; 103(2): 405-408, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38095655

RESUMEN

Immune thrombocytopenia (ITP) is a common bleeding disorder in children. First-line medicines (glucocorticoids and immunoglobulin) may not be effective for some children, endangering their lives, posing challenges for healthcare facilities, and leading to an unfavorable prognosis. As a sialidase inhibitor, oseltamivir phosphate can reduce the destruction of platelets in liver macrophages by inhibiting the sialylation of platelets, and finally achieve the purpose of increasing platelet count. In this paper, three cases of children with ITP who failed first-line therapy and were cured by oral administration of oseltamivir phosphate granules were reported. The mechanism of action of oseltamivir phosphate granules was clarified.


Asunto(s)
Púrpura Trombocitopénica Idiopática , Trombocitopenia , Niño , Humanos , Púrpura Trombocitopénica Idiopática/tratamiento farmacológico , Oseltamivir/uso terapéutico , Trombocitopenia/terapia , Recuento de Plaquetas , Plaquetas , Fosfatos
13.
BMC Plant Biol ; 23(1): 608, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38036992

RESUMEN

BACKGROUND: Despite GC variation constitutes a fundamental element of genome and species diversity, the precise mechanisms driving it remain unclear. The abundant sequence data available for the ITS2, a commonly employed phylogenetic marker in plants, offers an exceptional resource for exploring the GC variation across angiosperms. RESULTS: A comprehensive selection of 8666 species, comprising 165 genera, 63 families, and 30 orders were used for the analyses. The alignment of ITS2 sequence-structures and partitioning of secondary structures into paired and unpaired regions were performed using 4SALE. Substitution rates and frequencies among GC base-pairs in the paired regions of ITS2 were calculated using RNA-specific models in the PHASE package. The results showed that the distribution of ITS2 GC contents on the angiosperm phylogeny was heterogeneous, but their increase was generally associated with ITS2 sequence homogenization, thereby supporting the occurrence of GC-biased gene conversion (gBGC) during the concerted evolution of ITS2. Additionally, the GC content in the paired regions of the ITS2 secondary structure was significantly higher than that of the unpaired regions, indicating the selection of GC for thermodynamic stability. Furthermore, the RNA substitution models demonstrated that base-pair transformations favored both the elevation and fixation of GC in the paired regions, providing further support for gBGC. CONCLUSIONS: Our findings highlight the significance of secondary structure in GC investigation, which demonstrate that both gBGC and structure-based selection are influential factors driving angiosperm ITS2 GC content.


Asunto(s)
Magnoliopsida , Humanos , Magnoliopsida/genética , Filogenia , Conversión Génica , Composición de Base , ARN , Evolución Molecular
14.
Zhongguo Zhong Yao Za Zhi ; 48(21): 5915-5931, 2023 Nov.
Artículo en Chino | MEDLINE | ID: mdl-38114188

RESUMEN

This study used UPLC-TQ-MS technology to replicate a Henoch-Schonlein purpura(HSP) model in rats by administering warm drugs by gavage and injecting ovalbumin with Freund's complete adjuvant emulsion. The distribution differences and characteristics of eight major components(ferulic acid, caffeic acid, neochlorogenic acid, cryptochlorogenic acid, benzoyl oxypaeoniflorin, tracheloside, loganin, and paeoniflorin) in rat liver, lung, heart, spleen, and kidney tissues were determined after oral administration of the Liangxue Tuizi Mixture at a dose of 42 g·kg~(-1) in both normal physiological and HSP states at 0.5, 1, 2, 6, and 12 hours. The results showed that the distribution patterns of the eight components of Liangxue Tuizi Mixture in the tissues of normal and HSP model rats were different. The main component, paeoniflorin, in Moutan Cortex and Paeoniae Radix Alba had higher content in all tissues. The eight components were predominantly distributed in the liver, lung, and kidney tissues, followed by spleen and heart tissues.


Asunto(s)
Vasculitis por IgA , Ratas , Animales , Vasculitis por IgA/tratamiento farmacológico , Monoterpenos , Administración Oral , Cromatografía Líquida con Espectrometría de Masas
15.
Nutrients ; 15(18)2023 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-37764669

RESUMEN

The COVID-19 pandemic has stimulated collaborative drug discovery efforts in academia and the industry with the aim of developing therapies and vaccines that target SARS-CoV-2. Several novel therapies have been approved and deployed in the last three years. However, their clinical application has revealed limitations due to the rapid emergence of viral variants. Therefore, the development of next-generation SARS-CoV-2 therapeutic agents with a high potency and safety profile remains a high priority for global health. Increasing awareness of the "back to nature" approach for improving human health has prompted renewed interest in natural products, especially dietary polyphenols, as an additional therapeutic strategy to treat SARS-CoV-2 patients, owing to its good safety profile, exceptional nutritional value, health-promoting benefits (including potential antiviral properties), affordability, and availability. Herein, we describe the biological properties and pleiotropic molecular mechanisms of dietary polyphenols curcumin, resveratrol, and gossypol as inhibitors against SARS-CoV-2 and its variants as observed in in vitro and in vivo studies. Based on the advantages and disadvantages of dietary polyphenols and to obtain maximal benefits, several strategies such as nanotechnology (e.g., curcumin-incorporated nanofibrous membranes with antibacterial-antiviral ability), lead optimization (e.g., a methylated analog of curcumin), combination therapies (e.g., a specific combination of plant extracts and micronutrients), and broad-spectrum activities (e.g., gossypol broadly inhibits coronaviruses) have also been emphasized as positive factors in the facilitation of anti-SARS-CoV-2 drug development to support effective long-term pandemic management and control.


Asunto(s)
COVID-19 , Curcumina , Gosipol , Humanos , Resveratrol , Curcumina/farmacología , Pandemias , SARS-CoV-2 , Polifenoles/farmacología , Antivirales/farmacología , Antivirales/uso terapéutico
16.
World J Clin Cases ; 11(20): 4912-4919, 2023 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-37584000

RESUMEN

BACKGROUND: The clinical symptoms and imaging manifestations of neurocysticercosis (NCC) are very different, and the difficulty and delay of clinical diagnoses may lead to an increase in mortality and disability. Rapid and accurate pathogen identification is important for the treatment of these patients. Metagenomic next-generation sequencing (mNGS) is a powerful tool to identify pathogens, especially in infections that are difficult to identify by conventional methods. CASE SUMMARY: A 43-year-old male patient was admitted due to a recurrent headache for a few months. Imaging examinations showed hydrocephalus and cystic lesions, which were considered to be a central nervous system infection, but no etiology was found by routine examination. mNGS of the cerebrospinal fluid revealed high Taenia solium reads, and the positive results of a cysticercosis antibody test confirmed the infection. Combined with the patient's clinical manifestations, the etiological evidence, and the imaging manifestation, the patient was finally diagnosed with NCC and he was prescribed dexamethasone, albendazole, neurotrophic drugs, and intracranial pressure reduction therapy. The headaches disappeared after anti-parasite treatment, and no associated symptoms recurred prior to the three- and six-month follow-up. CONCLUSION: As an accurate and sensitivity detection method, mNGS can be a reliable approach for the diagnosis of NCC.

17.
Zhongguo Zhong Yao Za Zhi ; 48(12): 3327-3344, 2023 Jun.
Artículo en Chino | MEDLINE | ID: mdl-37382017

RESUMEN

Ultra-performance liquid chromatography-quadrupole time of fight/mass spectrometry(UPLC-Q-TOF-MS) and UNIFI were employed to rapidly determine the content of the components in Liangxue Tuizi Mixture. The targets of the active components and Henoch-Schönlein purpura(HSP) were obtained from SwissTargetPrediction, Online Mendelian Inheritance in Man(OMIM), and GeneCards. A "component-target-disease" network and a protein-protein interaction(PPI) network were constructed. Gene Ontology(GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis were performed for the targets by Omishare. The interactions between the potential active components and the core targets were verified by molecular docking. Furthermore, rats were randomly assigned into a normal group, a model group, and low-, medium-, and high-dose Liangxue Tuizi Mixture groups. Non-targeted metabolomics was employed to screen the differential metabolites in the serum, analyze possible metabolic pathways, and construct the "component-target-differential metabolite" network. A total of 45 components of Liangxue Tuizi Mixture were identified, and 145 potential targets for the treatment of HSP were predicted. The main signaling pathways enriched included resistance to epidermal growth factor receptor tyrosine kinase inhibitors, phosphatidylinositol 3-kinase/protein kinase B(PI3K-AKT), and T cell receptor. The results of molecular docking showed that the active components in Liangxue Tuizi Mixture had strong binding ability with the key target proteins. A total of 13 differential metabolites in the serum were screened out, which shared 27 common targets with active components. The progression of HSP was related to metabolic abnormalities of glycerophospholipid and sphingolipid. The results indicate that the components in Liangxue Tuizi Mixture mainly treats HSP by regulating inflammation and immunity, providing a scientific basis for rational drug use in clinical practice.


Asunto(s)
Vasculitis por IgA , Animales , Ratas , Vasculitis por IgA/tratamiento farmacológico , Farmacología en Red , Simulación del Acoplamiento Molecular , Fosfatidilinositol 3-Quinasas , Metabolómica
18.
Zhongguo Zhong Yao Za Zhi ; 48(10): 2639-2645, 2023 May.
Artículo en Chino | MEDLINE | ID: mdl-37282925

RESUMEN

This study investigated the effect of multi-glycosides of Tripterygium wilfordii(GTW) on renal injury in diabetic kidney disease(DKD) rats through Nod-like receptor protein 3(NLRP3)/cysteine-aspartic acid protease-1(caspase-1)/gsdermin D(GSDMD) pyroptosis pathway and the mechanism. To be specific, a total of 40 male SD rats were randomized into the normal group(n=8) and modeling group(n=34). In the modeling group, a high-sugar and high-fat diet and one-time intraperitoneal injection of streptozotocin(STZ) were used to induce DKD in rats. After successful modeling, they were randomly classified into model group, valsartan(Diovan) group, and GTW group. Normal group and model group were given normal saline, and the valsartan group and GTW group received(ig) valsartan and GTW, respectively, for 6 weeks. Blood urea nitrogen(BUN), serum creatinine(Scr), alanine ami-notransferase(ALT), albumin(ALB), and 24 hours urinary total protein(24 h-UTP) were determined by biochemical tests. The pathological changes of renal tissue were observed based on hematoxylin and eosin(HE) staining. Serum levels of interleukin-1ß(IL-1ß) and interleukin-18(IL-18) were detected by enzyme-linked immunosorbent assay(ELISA). Western blot was used to detect the expression of pyroptosis pathway-related proteins in renal tissue, and RT-PCR to determine the expression of pyroptosis pathway-related genes in renal tissue. Compared with the normal group, the model group showed high levels of BUN, Scr, ALT, and 24 h-UTP and serum levels of IL-1ß and IL-18(P<0.01), low level of ALB(P<0.01), severe pathological damage to kidney, and high protein and mRNA levels of NLRP3, caspase-1, and GSDMD in renal tissue(P<0.01). Compared with the model group, valsartan group and GTW group had low levels of BUN, Scr, ALT, and 24 h-UTP and serum levels of IL-1ß and IL-18(P<0.01), high level of ALB(P<0.01), alleviation of the pathological damage to the kidney, and low protein and mRNA levels of NLRP3, caspase-1, and GSDMD in renal tissue(P<0.01 or P<0.05). GTW may inhibit pyroptosis by decreasing the expression of NLRP3/caspase-1/GSDMD in renal tissue, thereby relieving the inflammatory response of DKD rats and the pathological injury of kidney.


Asunto(s)
Diabetes Mellitus , Nefropatías Diabéticas , Ratas , Masculino , Animales , Nefropatías Diabéticas/tratamiento farmacológico , Nefropatías Diabéticas/genética , Interleucina-18/metabolismo , Glicósidos/farmacología , Tripterygium , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Ratas Sprague-Dawley , Caspasa 1/metabolismo , Piroptosis , Uridina Trifosfato/metabolismo , Uridina Trifosfato/farmacología , Riñón , Valsartán/metabolismo , Valsartán/farmacología , ARN Mensajero/metabolismo
19.
Int J Mol Sci ; 24(9)2023 Apr 23.
Artículo en Inglés | MEDLINE | ID: mdl-37175423

RESUMEN

Guanine and cytosine (GC) content is a fundamental component of genetic diversity and essential for phylogenetic analyses. However, the GC content of the ribosomal internal transcribed spacer 2 (ITS2) remains unknown, despite the fact that ITS2 is a widely used phylogenetic marker. Here, the ITS2 was high-throughput sequenced from 29 Corydalis species, and their GC contents were comparatively investigated in the context of ITS2's characteristic secondary structure and concerted evolution. Our results showed that the GC contents of ITS2 were 131% higher than those of their adjacent 5.8S regions, suggesting that ITS2 underwent GC-biased evolution. These GCs were distributed in a heterogeneous manner in the ITS2 secondary structure, with the paired regions being 130% larger than the unpaired regions, indicating that GC is chosen for thermodynamic stability. In addition, species with homogeneous ITS2 sequences were always GC-rich, supporting GC-biased gene conversion (gBGC), which occurred with ITS2's concerted evolution. The RNA substitution model inferred also showed a GC preference among base pair transformations, which again supports gBGC. Overall, structurally based GC investigation reveals that ITS2 evolves under structural stability and gBGC selection, significantly increasing its GC content.


Asunto(s)
Corydalis , ADN Espaciador Ribosómico/genética , Filogenia , Evolución Molecular , Emparejamiento Base
20.
Sci Rep ; 13(1): 8361, 2023 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-37225746

RESUMEN

For some new mines, the utilization rate of tailings is not satisfactory when using unclassified tailings as backfill aggregate for cemented backfill. At the same time, with the progress of mineral processing technology, the tailings discharged by the concentrator gradually become finer. Therefore, cemented filling with fine-grained tailings as aggregate will become the development direction of filling technology in the future. In this paper, the feasibility of fine particle tailings backfill is studied by taking the particle tailings of-200 mesh as aggregate in Shaling gold mine. The calculation shows that the utilization rate of tailings is increased from 45.1% to 90.3% by using-200 mesh tailings as filling aggregate. The response surface central composite design method (RSM-CCD) was used to study the strength of backfill with alkali-activated cementitious material as binder by taking the mass concentration of backfill slurry and sand-binder ratio as input factors. The results show that the 28-day strength of the backfill with graded fine-grained tailings as filling aggregate can reach 5.41 MPa when the sand-binder ratio is 4, which can fully meet the needs of the mine for the strength of the backfill. The thickening test of-200 mesh fine particle tailings was carried out by static limit concentration test and dynamic thickening test. In the case of adding 35 g/t BASF 6920 non-ionic flocculant, the concentration of 64.74% tail mortar can reach 67.71% after 2 h of static thickening, and the concentration can reach 69.62% after 2 h of static thickening. The feeding speed of thickener should be controlled between 0.4 and 0.59 t/(m2 h). In this case, the underflow concentration of thickener is relatively high, which is 64.92-65.78%, and the solid content of overflow water is less than 164 ppm. The conventional full tailings thickening process was improved by using the design of high-efficiency deep cone thickener and vertical sand silo. The feasibility of fine-grained tailings as filling aggregate was demonstrated by combining the filling ratio test of fine-grained tailings, the data of thickening test and the improved thickening process. The research results can provide reference for other mines to use fine-grained tailings as filling aggregate to design filling system.

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