Learning to reconstruct accelerated MRI through K-space cold diffusion without noise.

Deep learning-based MRI reconstruction models have achieved superior performance these days. Most recently, diffusion models have shown remarkable performance in image generation, in-painting, super-resolution, image editing and more. As a generalized diffusion model, cold diffusion further broadens the scope and considers models built around arbitrary image transformations such as blurring, down-sampling, etc. In this paper, we propose a k-space cold diffusion model that performs image degradation and restoration in k-space without the need for Gaussian noise. We provide comparisons with multiple deep learning-based MRI reconstruction models and perform tests on a well-known large open-source MRI dataset. Our results show that this novel way of performing degradation can generate high-quality reconstruction images for accelerated MRI.

Localized nitrogen management strategies can halve fertilizer use in Chinese staple crop production.

Nitrogen (N) management is the key to achieving food security and environmental sustainability. Here we analyse N flows using a localized N management model for wheat, maize and rice in 1,690 Chinese counties, with a breakdown of multiple reactive N (Nr) loss pathways. Results show that the total N input for producing these three staple crops in China was 22.2 Tg N in 2015, of which 7.4 Tg N was harvested as grain N and 4.0 Tg N was Nr losses in the forms of NH3 (47%), NOx (10%), N2O (3%), and leaching and runoff (40%). By assuming a production level equivalent to that of the top 10% of counties with the highest N use efficiency and yields surpassing the regional average, we reveal the possibility of achieving national staple crop production targets while improving net ecosystem economic benefit in 2050 through a 49% reduction (10.4 Tg N) in synthetic N fertilizer inputs and a 52% decrease (2.9 Tg N) in Nr losses.

Chromosome-level genome assemblies of two littorinid marine snails indicate genetic basis of intertidal adaptation and ancient karyotype evolved from bilaterian ancestors.

Living in the intertidal environment, littorinid snails are excellent models for understanding genetic mechanisms underlying adaptation to harsh fluctuating environments. Furthermore, the karyotypes of littorinid snails, with the same chromosome number as the presumed bilaterian ancestor, make them valuable for investigating karyotype evolution from the bilaterian ancestor to mollusks. Here, we generated high-quality, chromosome-scale genome assemblies for 2 littorinid marine snails, Littorina brevicula (927.94 Mb) and Littoraria sinensis (882.51 Mb), with contig N50 of 3.43 Mb and 2.31 Mb, respectively. Comparative genomic analyses identified 92 expanded gene families and 85 positively selected genes as potential candidates possibly associated with intertidal adaptation in the littorinid lineage, which were functionally enriched in stimulus responses, innate immunity, and apoptosis process regulation and might be involved in cellular homeostasis maintenance in stressful intertidal environments. Genome macrosynteny analyses indicated that 4 fissions and 4 fusions led to the evolution from the 17 presumed bilaterian ancestral chromosomes to the 17 littorinid chromosomes, implying that the littorinid snails have a highly conserved karyotype with the bilaterian ancestor. Based on the most parsimonious reconstruction of the common ancestral karyotype of scallops and littorinid snails, 3 chromosomal fissions and 1 chromosomal fusion from the bilaterian ancient linkage groups were shared by the bivalve scallop and gastropoda littorinid snails, indicating that the chromosome-scale ancient gene linkages were generally preserved in the mollusk genomes for over 500 million years. The highly conserved karyotype makes the littorinid snail genomes valuable resources for understanding early bilaterian evolution and biology.

Spectroscopic Relationship between XOD and TAOZHI Total Polyphenols Based on Chemometrics and Molecular Docking Techniques.

Xanthine oxidase (XOD) is a key enzyme that promotes the oxidation of xanthine/hypoxanthine to form uric acid, and the accumulation of uric acid leads to hyperuricaemia. The prevalence of gout caused by hyperuricaemia is increasing year by year. TAOZHI (TZ) can be used for the treatment of rheumatic arthralgia due to qi stagnation and blood stasis and contains a large number of polyphenolic components. The aim of this study was to investigate the relationship between chromatograms and XOD inhibition of 21 batches of TZ total polyphenol extract samples. Chemometric methods such as grey correlation analysis, bivariate correlation analysis, and partial least squares regression were used to identify the active ingredient groups in the total polyphenol extracts of TZ, which were validated using molecular docking techniques. The total polyphenol content contained in the 21 batches did not differ significantly, and all batches showed inhibitory effects on XOD. Spectroeffect correlation analysis showed that the inhibitory effect of TZ on XOD activity was the result of the synergistic effect of multiple components, and the active component groups screened to inhibit XOD were F2 (4-O-Caffeoylquinic acid), F4, and F10 (naringenin). The molecular docking results showed that the binding energies of all nine dockings were lower than -7.5 kcal/mol, and the binding modes included hydrogen bonding, hydrophobic forces, salt bridges, and π-staking, and the small molecules might exert their pharmacological effects by binding to XOD through the residue sites of the amino acids, such as threonine, arginine, and leucine. This study provides some theoretical basis for the development and utilisation of TZ total polyphenols.

Exosomal miR-552-3p isolated from BALF of patients with silicosis induces fibroblast activation.

BACKGROUND: Silica particles can cause silicosis, a disease characterized by diffuse fibrosis of the lungs. Various signaling pathways composed of different types of cells and cytokines are involved in the development of silicosis. Exosomes have become a research hotspot recently. However, the role of exosomal microRNA (miRNA) in silicosis remains unclear. METHODS: In this study, we generated exosomal miRNA sequences from exosomes isolated from bronchoalveolar lavage fluid (BALF) of silicosis patients and the control group by high-throughput sequencing. Functional annotation and analysis of miRNA identified key target miRNAs. Levels of target miRNAs were analyzed in patient and animal samples and cells. Effects of increased miRNA were assessed through protein levels in target signaling pathways in cells treated with silica, miRNA mimics, and inhibitors. RESULTS: Our study identified 40 up-regulated and 70 down-regulated miRNAs, with miR-552-3p and its putative target gene Caveolin 1 (CAV1) as targets for further research. We found that the levels of exosomal miR-552-3p increased in silicosis patients' BALF samples, silicosis model mice, and A549 cells exposed to silica. Inhibition of miR-552-3p suppressed the expression of fibrosis markers. The increased miR-552-3p leads to the up-regulation of fibronectin and α-smooth muscle actin (α-SMA) and the suppression of caveolin 1 in fibroblast cells. Mitogen-activated protein kinase (MAPK) signaling pathways are activated in cells treated with silica and miR-552-3p mimics. CONCLUSIONS: These results help to understand exosomal miRNA-mediated intercellular communication and its key role in fibroblast activation and silicosis.

Intracerebroventricular injection of α-synuclein preformed fibrils do not induce motor and olfactory impairment in C57BL/6 mice.

INTRODUCTION: Alpha-synuclein (αSyn) is believed to play a central role in the pathogenesis of Parkinson's disease (PD). Cerebrospinal fluid (CSF) total αSyn were significantly lower in PD patients, whereas the aggregates were higher, and this phenomenon was further exacerbated with longer disease duration. However, whether CSF αSyn can be the cause and/or a consequence in PD is not fully elucidated. METHOD: We administered 2 ng or 200 ng αSyn preformed fibrils (PFFs) by intracerebroventricular injection for consecutive 7 days in C57BL/6 mice. The olfactory function was assessed by the olfactory discrimination test and buried food-seeking test. The locomotor function was assessed by the rotarod test, pole test, open field test and CatWalk gait analysis. Phosphorylated αSyn at serine 129 was detected by the immunohistochemistry staining. Iron levels was determined by Perl's-diaminobenzidine iron staining and synchrotron-based X-ray fluorescence. RESULTS: The mice did not exhibit any diffuse synucleinopathy in the brain for up to 30 weeks, although αSyn PFFs induced aggregation in SH-SY5Y cells and in the substantia nigra and striatum of mice with stereotactic injection. No impairment of motor behaviors or olfactory functions were observed, although there was a temporary motor enhancement at 1 week. We then demonstrated iron levels were comparable in certain brain regions, suggesting there was no iron deposition/redistribution occurred. CONCLUSION: The intraventricular injection of αSyn PFFs does not induce synucleinopathy or behavioral symptoms. These findings have implications that CSF αSyn aggregates may not necessarily contribute to the onset or progression in PD.

Structural characterisation of a novel polysaccharide from pseudostellaria heterophylla fibrous root and its anti-inflammatory and antioxidant activities in vitro.

A novel water-soluble polysaccharide, named PF90-1, with a molecular weight of 1.8 kDa, was isolated and purified from the fibrous root of Pseudostellaria heterophylla. PF90-1 is composed of Gal, Glc and Man in a molar ratio of 73.61: 19.11: 7.28. Methylation analysis revealed that PF90-1 comprises of T-Galp, 1,4-Galp, 1,3,4-Galp, 1,2,3,4-Galp, T-Glcp and 1,3-Manp in a molar ratio of 37.89: 9.37: 17.01: 12.01: 15.88: 7.83. Bioactivity experiments showed that PF90-1 significantly improved lipopolysaccharide (LPS)-induced inflammatory damage in RAW264.7 cells by inhibiting nitric oxide (NO) production and reducing the levels of pro-inflammatory factors (IL-1ß and TNF-α). In addition, PF90-1 exhibited strong antioxidant effects, protecting PC12 cells from H2O2-induced oxidative damage. This findings suggest that PF90-1 holds potential therapeutic value for the treatment of inflammatory and oxidative injuries.

A comprehensive survey of the clinical trial Landscape on digital therapeutics.

Background: Digital therapeutics (DTx) is an emerging and groundbreaking medical intervention that utilizes health software to treat or alleviate various diseases, disorders, conditions, or injuries. Although the potential of digital therapy is enormous, it is still in its nascent stage and faces multiple challenges and obstacles. The purpose of this study is to provide an overview of all DTx-related clinical trials in ClinicalTrials.gov and to promote the advancement of DTx. Methods: Two reviewers and one expert evaluated data from all DTx clinical trials on ClinicalTrials.gov as of August 8, 2023. Trials utilizing digital therapeutics independently or in combination with traditional approaches were included. Incomplete trials and those lacking an evidence-based foundation were excluded. Basic information about product launches and primary outcome measures was extracted and analyzed. Results: A total of 280 eligible trials were categorized into treating a disease (141, 50.4 %), managing a disease (120, 42.9 %), and improving a health function (19, 6.8 %). The focus was primarily on mental and behavioral disorders, neurological disorders, and endocrine, nutritional, and metabolic disorders. The number of trials has been increasing annually, yet trial design and conduct remain inconsistent. Randomized controlled trials (RCTs) accounted for 67.5 % of completed trials, and 36 trials (12.9 %) involved products already approved for marketing. Conclusions: The growth in clinical studies on DTx underscores their potential in healthcare. However, challenges persist in standardization, regulation, and clinical efficacy. There is a need for a harmonized global classification of digital therapeutics and standardized clinical trial protocols to ensure efficacy and improve healthcare services.

Differential analysis of ubiquitin-proteomics in skeletal muscle of Duroc pigs and Tibetan fragrant pigs.

Understanding the differences in ubiquitination-modified proteins between Duroc pigs and Tibetan fragrant pigs is crucial for comprehending the growth and development of their skeletal muscles. In this study, skeletal muscle samples from 30-day-old Duroc pigs and Tibetan fragrant pigs were collected. Using ubiquitination 4D-Label free quantitative proteomics, we analyzed and identified ubiquitination-modified peptides, screening out 109 differentially expressed ubiquitination-modified peptides. Further enrichment analysis was conducted on the proteins associated with these differential peptides. GO analysis results indicated that the differential genes were primarily enriched in processes such as regulation of protein transport, motor activity, myosin complex, and actin cytoskeleton. KEGG pathway analysis revealed significant enrichment in pathways such as Glycolysis/Gluconeogenesis and Hippo signaling pathway. The differentially expressed key ubiquitinated proteins, including MYL1, MYH3, TNNC2, TNNI1, MYLPF, MYH1, MYH7, TNNT2, TTN, and TNNC1, were further identified. Our analysis demonstrates that these genes play significant roles in skeletal muscle protein synthesis and degradation, providing new insights into the molecular mechanisms of muscle development in Duroc pigs and Tibetan fragrant pigs, and offering theoretical support for breeding improvements in the swine industry.

Medication-related osteonecrosis of the jaw: a retrospective single center study of recurrence-related factors after surgical treatment.

OBJECTIVES: To provide an overview of the features of patients with medication-related osteonecrosis of the jaw (MRONJ) and explore recurrence-related factors after surgery. MATERIALS AND METHODS: All pathological records of patients diagnosed with osteonecrosis or osteomyelitis of the jaw were reviewed. Only patients who had a history of use of medication related to bone turnover were included. All demographic and clinical characteristics were collected during review. Univariate and logistic regression analyses were performed to evaluate the associations between risk factors and recurrence. A p value < 0.05 was considered to indicate statistical significance in all analyses. RESULTS: A total of 313 patients were ultimately included. Most patients (89.14%) underwent bone turnover-related treatment due to malignancy. The breast and prostate were the most common locations of primary tumors in females and males, respectively. Almost all MRONJ patients experienced inflammatory symptoms. Recurrence occurred in 55 patients at 60 locations. The total recurrence rate was 16.85%, with no significant differences between the maxilla and mandible. Extensive surgery and flap transfer were strongly related to a lower recurrence risk. Nearly 80% of patients had recurrence-related symptoms within 6 months. CONCLUSION: When MRONJ is treated with surgical methods, extensive resection and flap transfer can reduce recurrence risk. Six-month follow-up is needed to exclude recurrence after surgery. CLINICAL RELEVANCE: This study revealed the surgical-related risk factors, such as extensive surgery and flap transfer, when treating MRONJ patients, and 6-month follow-up is needed to detect recurrence. This could provide clinical guidance for head and neck surgeons.

Prospects for global sustainable development through integrating the environmental impacts of economic activities.

Human economic activities drive the production and consumption of goods and services, contribute to the achievement of the United Nations Sustainable Development Goals (SDGs). However, the extent of economic growth's influence on the SDGs remains unclear. To fill this knowledge gap, here, we quantified the environmental effects of economic activities and explored correlations between environmental effect and achieving SDGs. We developed six Environmental Footprint Indices, with a higher score indicating better efficiency or lower burden. Here we show that the various Environmental Footprint Indices had synergistic and trade-off effects on most SDG targets indices, but the synergistic effects prevailed. As income increased, the correlation between Environmental Footprint Indices and SDG target indices gradually strengthened. improved production efficiency and consumption changes notably advance SDGs, especially in low-income group countries. Our work provides scientific insights into the impact and prospects of environmental regulation required for achieving the SDGs by 2030.

Topological Rearrangement-Induced Mesoscale Phase Redistribution to Enhance the Fatigue Resistance of Polymer Blends.

Maintaining a high modulus to simultaneously withstand deformation and increase fatigue resistance to restrict crack propagation in a material presents a significant challenge. In this work, a straightforward strategy was developed to address this issue in polymers. A dynamic network was incorporated into a permanent one prior to the formation of the latter, and two incompatible polymer networks were created to prevent common phase separation. The mechanical and fatigue resistance properties were substantially enhanced by the exact modulation of the soft and hard phase distribution by precise control over the densities of dynamic and permanent networks as well as the number of reprocessing steps. The experimental results demonstrated a nearly 9-fold increase in the fatigue life of polyurethane compared with traditional design methods and a 2.5 times increase in modulus. This strategy shows potential for the design of fatigue-resistant thermosetting and thermoplastic materials. The results offer new insight into the development of durable, high-performance materials that are reprocessable and compatible.

Tailored endothelialization enabled by engineered endothelial cell vesicles accelerates remodeling of small-diameter vascular grafts.

Current gold standard for the replacement of small-diameter blood vessel (ID < 4 mm) is still to utilize the autologous vessels of patients due to the limitations of small-diameter vascular grafts (SDVG) on weak endothelialization, intimal hyperplasia and low patency. Herein, we create the SDVG with the tailored endothelialization by applying the engineered endothelial cell vesicles to camouflaging vascular grafts for the enhancement of vascular remodeling. The engineered endothelial cell vesicles were modified with azide groups (ECVs-N3) through metabolic glycoengineering to precisely link the vascular graft made of PCL-DBCO via click chemistry, and thus fabricating ECVG (ECVs-N3 modified SDVG), which assists inhibition of platelet adhesion and activation, promotion of ECs adhesion and enhancement of anti-inflammation. Furthermore, In vivo single-cell transcriptome analysis revealed that the proportion of ECs in the cell composition of ECVG surpassed that of PCL, and the tailored endothelialization enabled to convert endothelial cells (ECs) into some specific ECs clusters. One of the specific cluster, Endo_C5 cluster, was only detected in ECVG. Consequently, our study integrates the engineered membrane vesicles of ECVs-N3 from native ECs for tailored endothelialization on SDVG by circumventing the limitations of living cells, and paves a new way to construct the alternative endothelialization in vessel remodeling following injury.

Optimization and Spectrum-Effect Analysis of Ultrasonically Extracted Antioxidant Flavonoids from Persicae Ramulus.

The objectives of this study were to optimize the ultrasonic-assisted flavonoid extraction process from PR and to establish fingerprints in order to analyze the spectrum-effect relationship of antioxidant activity. The ultrasonic-assisted flavonoid extraction process from PR was optimized using RSM, and the fingerprints of twenty-eight batches of flavonoids from PR were established using UHPLC. Meanwhile, the in vitro antioxidant activity of PR was evaluated in DPPH and ABTS free radical-scavenging experiments. Then, the peaks of the effective antioxidant components were screened using the spectrum-effect relationships. The results show that the optimal extraction yield of flavonoids from PR was 3.24 ± 0.01 mg/g when using 53% ethanol, a 1:26 (g/mL) solid-liquid ratio, and 60 min of ultrasonic extraction. Additionally, the clearance of two antioxidant indices by the flavonoids extracted from PR had different degrees of correlation and showed concentration dependence. Simultaneously, the similarity of the UHPLC fingerprints of twenty-eight batches of PR samples ranged from 0.801 to 0.949, and four characteristic peaks, namely peaks 4, 12, 21, and 24, were screened as the peaks of the components responsible for the antioxidant effect of PR using a GRA, a Pearson correlation analysis, and a PLS-DA. In this study, characteristic peaks of the antioxidant effects of PR were screened in an investigation of the spectrum-effect relationship to provide a scientific basis for the study of pharmacodynamic substances and the elucidation of the mechanism of action of the antioxidant effect of PR.

Jianwei Xiaoyan granule ameliorates chronic atrophic gastritis by regulating HIF-1α-VEGF pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Jianwei Xiaoyan Granule (JWXYG) is the traditional Chinese medicine preparation in Jiangyin Hospital Affiliated to Nanjing University of Chinese Medicine, which has been widely used in clinical treatment of chronic atrophic gastritis (CAG). However, the material basis and potential mechanism of JWXYG in the treatment of CAG are not clear. PURPOSE: To explore the material basis and potential mechanism of JWXYG in the treatment of CAG. METHODS: In this study, the components of JWXYG were analyzed by HPLC-Q-TOF-MS/MS. Then, the CAG model in rats established by a composite modeling method and MC cell model induced by MNNG were used to explore the improvement effect of JWXYG on CAG. Finally, the potential mechanism of JWXYG in the treatment of CAG was preliminarily predicted based on network pharmacology and validated experimentally. RESULTS: Thirty-one components of JWXYG were analyzed through HPLC-Q-TOF-MS/MS, such as albiflorin, paeoniflorin, lobetyolin firstly. Research results in vivo showed that the gastric mucosa became thinner, intestinal metaplasia appeared, the number of glands was reduced, the serum levels of PG I and PG II increased and the contents of G17 and IL-6 reduced in CAG model rats. After 4 weeks of JWXYG (2.70 g/kg) administration, these conditions were significantly improved. In addition, cell viability, migration, and invasion of MNNG-induced MC cells was inhibited by JWXYG treatment (800 µg/mL). Furthermore, the results of network pharmacology indicated that HIF-1 and VEGF signaling pathways might play important roles in the therapeutic process. Then the results of Western blot, immunohistochemistry and immunofluorescence confirmed that with JWXYG treatment, the increased expression of HIF-1α, VEGF and VEGFR2 in gastric issue of CAG rats were restrained. Eventually, potential components of JWXYG in the treatment of CAG were predicted through molecular docking to elucidate the material basis. CONCLUSION: JWXYG could inhibit angiogenesis by regulating HIF-1α-VEGF pathway to exert therapeutic effects on CAG. Our study explored the potential mechanisms and material basis of JWXYG in the treatment of CAG and provides experimental data for the clinical rational application of JWXYG.

A 62.2dB SNDR Event-Driven Level-Crossing ADC with SAR-Assisted Delay Compensation Loop for Time-Sparse Biomedical Signal Acquisition.

This paper proposed an event-driven clockless level-crossing ADC (LC-ADC) suitable for biomedical applications. Thanks to the LC loop, the sampling rate of the converter automatically adapts to the input activities. Activity-dependent power consumption and data compression can thus be realized, saving system power, especially during time-sparse signal acquisition. Meanwhile, a SAR-assisted loop is exploited to resolve the loop-delay-induced distortion in conventional LC-ADC. Therefore, the resolution and power efficiency of the LC-ADC are improved effectively while maintaining the event-driven feature. Implemented in a 55nm process, the proposed LC-ADC achieves a scalable power consumption and a peak SNDR of 62.2dB for a 20kHz input. It also achieves a Walden FoM of 29.7fJ/conv.-step and a Schreier FoM of 158.6dB, which is best in class, without using off-chip calibration. Sub µW power is realized when the input frequency is below 1.5kHz. The proposed LC-ADC is also verified by simulated electrocardiogram (ECG), neural spike, and electromyogram (EMG) signals. It provides a ~7X data compression for ECG input, providing an attractive solution for time-sparse signal acquisition in biomedical applications.

Quantitative identification on spatial mismatch characteristics between supply and demand of carbon sequestration services.

Exploring the mismatch between supply and demand (SD) for carbon sequestration services (CSS) is essential for achieving the "double carbon" goal. However, more studies are needed on the traits of the spatial mismatch between SD in mountainous cities. We used the CASA model and the IPCC emission factor approach to address this issue and quantify the SD of CSS in Chongqing. Second, we established a matching relationship model for the SD of CSS in Chongqing. Finally, we applied the Structural Equation Model with the Partial Dependence Plots model to reveal the influencing factors and internal mechanisms of spatial mismatch between the SD of CSS in Chongqing. The outcomes confirmed a decrease in fashion in the total supply of CSS in Chongqing and growth in fashion in general demand from 2000 to 2020. The SD mismatch was mainly concentrated inside the central city and other built-up areas. The SD mismatch area had increased by 390%, indicating a continuous upward trend. In exploring the factors influencing the mismatch between the SD of CSS in Chongqing, supply is mainly positively influenced by NDVI, and demand and supply-demand relationships are influenced by population density and LUCC. We proposed policy suggestions to alleviate the spatial mismatch and practical significance for achieving the "double carbon" goal and promoting sustainable development.

Broadband and fabrication-tolerant 3-dB couplers with topological valley edge modes.

3-dB couplers, which are commonly used in photonic integrated circuits for on-chip information processing, precision measurement, and quantum computing, face challenges in achieving robust performance due to their limited 3-dB bandwidths and sensitivity to fabrication errors. To address this, we introduce topological physics to nanophotonics, developing a framework for topological 3-dB couplers. These couplers exhibit broad working wavelength range and robustness against fabrication dimensional errors. By leveraging valley-Hall topology and mirror symmetry, the photonic-crystal-slab couplers achieve ideal 3-dB splitting characterized by a wavelength-insensitive scattering matrix. Tolerance analysis confirms the superiority on broad bandwidth of 48 nm and robust splitting against dimensional errors of 20 nm. We further propose a topological interferometer for on-chip distance measurement, which also exhibits robustness against dimensional errors. This extension of topological principles to the fields of interferometers, may open up new possibilities for constructing robust wavelength division multiplexing, temperature-drift-insensitive sensing, and optical coherence tomography applications.

Generating open-source 3D phytoplankton models by integrating photogrammetry with scanning electron microscopy.

The community structure and ecological function of marine ecosystems are critically dependent on phytoplankton. However, our understanding of phytoplankton is limited due to the lack of detailed information on their morphology. To address this gap, we developed a framework that combines scanning electron microscopy (SEM) with photogrammetry to create realistic 3D (three-dimensional) models of phytoplankton. The workflow of this framework is demonstrated using two marine algal species, one dinoflagellate Prorocentrum micans and one diatom Halamphora sp. The resulting 3D models are made openly available and allow users to interact with phytoplankton and their complex structures virtually (digitally) and tangibly (3D printing). They also allow for surface area and biovolume calculations of phytoplankton, as well as the exploration of their light scattering properties, which are both important for ecosystem modeling. Additionally, by presenting these models to the public, it bridges the gap between scientific inquiry and education, promoting broader awareness on the importance of phytoplankton.

Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis.

Background: Overtreatment design of clear aligner treatment (CAT) in extraction cases is currently primarily based on the clinical experience of orthodontists and is not supported by robust evidence on the underlying biomechanics. This study aimed to investigate the biomechanical effects of overtreatment strategies involving different maxillary anterior teeth intrusion patterns during anterior teeth retraction by CAT in extraction cases. Materials and methods: A finite element model of the maxillary dentition with the first premolar extracted was constructed. A loading method of clear aligners (CAs) based on the initial state field was proposed. The iterative method was used to simulate the long-term orthodontic tooth movement under the mechanical load exerted by the CAs. Three groups of CAs were utilized for anterior teeth retraction (G0: control group; G1: incisors intrusion group; G2: anterior teeth intrusion group). Tooth displacement and occlusal plane rotation tendency were analyzed. Results: In G0, CAT caused lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, mesial tipping, and intrusion of the posterior teeth. In G1, the incisors showed minimal extrusion, whereas the canines showed increased extrusion and distal tipping tendency. G2 showed the smallest degree of posterior occlusal plane angle rotation, while the inclination tendency of the canines and second premolars decreased. Conclusion: 1. In CAT, tooth displacement tendency may change with increased wear time. 2. During anterior teeth retraction, the incisor intrusion pattern can provide effective vertical control for the lateral incisors but has little effect on the central incisors. Anterior teeth intrusion patterns can alleviate the inclination of canines and second premolars, resulting in partial relief of the roller-coaster effect.