Cellular automata inspired multistable origami metamaterials for mechanical learning

Recent advances in multistable metamaterials reveal a link between structural configuration transition and Boolean logic, heralding a new generation of computationally capable intelligent materials. To enable higher-level computation, existing computational frameworks require the integration of large-scale networked logic gates, which places demanding requirements on the fabrication of materials counterparts and the propagation of signals. Inspired by cellular automata, we propose a novel computational framework based on multistable origami metamaterials by incorporating reservoir computing, which can accomplish high-level computation tasks without the need to construct a logic gate network. This approach thus eleimates the demanding requirements for fabrication of materials and signal propagation when constructing large-scale networks for high-level computation in conventional mechano-logic. Using the multistable stacked Miura-origami metamaterial as a validation platform, digit recognition is successfully implemented through experiments by a single actuator. Moreover, complex tasks, such as handwriting recognition and 5-bit memory tasks, are also shown to be feasible with the new computation framework. Our research represents a significant advancement in developing a new generation of intelligent materials with advanced computational capabilities. With continued research and development, these materials could have a transformative impact on a wide range of fields, from computational science to material mechano-intelligence technology and beyond.Comment: 24 pages, 7 figure

Microbiome and metabolome associated with white spot lesions in patients treated with clear aligners

White spot lesions (WSLs) have long been a noteworthy complication during orthodontic treatment. Recently, an increasing number of orthodontists have found that adolescents undergoing orthodontic treatment with clear aligners are at a higher risk of developing WSLs. The oral microbiota and metabolites are considered the etiologic and regulatory factors of WSLs, but the specific impact of clear aligners on the oral microbiota and metabolites is unknown. This study investigated the differences in the salivary microbiome and metabolome between adolescents with and without WSLs treated with clear aligners. Fifty-five adolescents (aged 11-18) with Invisalign appliances, 27 with and 28 without WSLs, were included. Saliva samples were analyzed using 16S rRNA gene sequencing and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS); the data were further integrated for Spearman correlation analysis. The relative abundances of 14 taxa, including Actinobacteria, Actinomycetales, Rothia, Micrococcaceae, Subdoligranulum, Capnocytophaga, Azospira, Olsenella, Lachnoanaerobaculum, and Abiotrophia, were significantly higher in the WSL group than in the control group. Metabolomic analysis identified 27 potential biomarkers, and most were amino acids, including proline and glycine. The metabolites were implicated in 6 metabolic pathways, including alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism; and aminoacyl-tRNA biosynthesis. There was a correlation between the salivary microbial and metabolomic datasets, reflecting the impact of clear aligners on the metabolic activity of the oral flora. A concordant increase in the levels of Lachnoanaerobaculum, Rothia, Subdoligranulum and some amino acids had predictive value for WSL development. In summary, when adolescents undergo long-term clear aligner therapy with poor oral hygiene habits, clear aligners can disrupt the balance of the oral microecosystem and lead to oral microbiota dysbiosis, thereby increasing the risk of developing WSLs. Our findings might contribute to the understanding of the pathogenesis of WSLs and provide candidate biomarkers for the diagnosis and treatment of WSLs associated with clear aligners

Development and performance of a clear aligner film loaded with sustained release hydrogen peroxide gel

Introduction: Clear aligner treatment (CAT) has become popular over recent years because it is both comfortable and aesthetically acceptable. However, most of patients undergoing orthodontic treatment request dental bleaching. A safe and controlled bleaching treatment at the same time as the clear aligner treatment can save time and improve patient satisfaction with the outcome of the treatment.Aim: This study was aimed to develop a thermoforming film loaded with hydrogen peroxide as a clear aligner and detect its efficiency on teeth blenching and its influence on shear bonding strength for attachment.Methods: The thermoforming film loaded with sodium alginate-dopamine/Mesoporous silica nanoparticles compound gel was immersed in 6 wt% hydrogen peroxide solution and the hydrogen peroxide was loaded into mesoporous silica nanoparticle channels by capillary action. Then, a thermoforming film loaded with sustained-release hydrogen peroxide gel was made. Six dentition models were prepared with 90 isolated human premolars and divided into the experiment group, the condition control group and the blank control group, respectively. Then, the experiment group wore the clear aligner made by the thermoforming film loaded with hydrogen peroxide for 40 days; the conditional control group wore the clear aligner made by the ordinary thermoforming film for 40 days; and the blank control group wore no clear aligner. The aligners were updated every 10 days and the color of teeth was measured every 10 days. Tooth color should be determined by specific parameters (L, a* and b*). What’s more, in order to determine the influence of the thermoforming film loaded with sustained-release hydrogen peroxide gel on shear bonding strength for attachment. The shear bonding strength of attachment of isolated premolars were measured.Results: Isolated premolars treated by bleaching experiments showed an increase in L value (ΔL = 7.76 ± 0.64) and a decrease in both a* (Δa = −0.82 ± 0.12) and b* (Δb = −3.10 ± 0.21) values. However, the isolated premolars in conditional control group and blank control group exhibited that an decrease in L value (ΔLCCG = −0.91 ± 0.24; ΔLBCG = −0.86 ± 0.15)and a increase in both a* (ΔaCCG = 0.19 ± 0.05; ΔaBCG = 0.18 ± 0.04) and b* (ΔbCCG = 0.43 ± 0.11; ΔbBCG = 0.31 ± 0.10) value. While the shear bonding strength for attachment after bleaching was 22.78 ± 2.28 MPa, which had no significant change compared with the shear bonding strength for attachment without bleaching experiment (22.21 ± 2.77 MPa) (p > 0.05). Conclusion: A thermoforming film featuring the sustained release of hydrogen peroxide had a good bleaching effect on isolated teeth and had no significant influence on the shear bonding strength for attachment

THE DEPENDENCE OF ELECTRICAL RESISTIVITY, SATURATION AND SATURATION EXPONENT ON MULTI-PHASE FLOW INSTABILITY

Multiphase flow channeling in oil reservoirs during water floods reduces oil recovery. Electrical methods may be used to monitor reservoirs and detect the onset of channeling, but the dependence of electrical resistivity on reservoir flow conditions is complex. The present study is directed toward understanding how the parameters of Archie\u27s law, a commonly assumed relationship between electrical resistivity and water saturation in a porous medium, depends on multiphase flow instability leading to flow channeling. In this research a series of 34 flow experiments were conducted in a thin, two-dimensional tank (55cm x 55cm x 3.75cm) packed with 2mm glass beads where mineral oil was displaced by Nigrosine dyed water. The tank was designed to tilt to arbitrary angles, thereby allowing experiments to be conducted for different values of the generalized Bond number, which describes the overall balance between viscous, capillary, and gravity forces affecting flow instability, by varying the water application rate and orientation of the tank. The effective electrical resistivity of the tank was measured continuously during the flow experiments using a National Instruments digital multi-meter (NI PXI-4071 7 1/2 Digit Flex DMM). Concurrently, a light transmission method was used to monitor spatial variations of oil and water saturation in the tank using a digital camera. The saturation images were then used to derive the average tank saturation over time. The resistivity index derived from Archie\u27s law generally decreases as the water saturation increases in the tank and sharp drops are observed when individual fingers of water span the entire tank to create a continuous electrically conductive pathway. The magnitude of this resistivity index drop decreases when the displacement pattern becomes more unstable and disappears under highly unstable flow conditions. Based on the resistivity and saturation data, the saturation exponent in Archie\u27s law was estimated over the course of the experiment for each set of experimental conditions. The saturation exponent increases as the water displaces oil and reaches a constant value after water breakthrough occurs and a stable flow pattern is established. At equilibrium, the saturation exponent increases from 0.65 to 1.94 as the generalized Bond number is decreased to transition between stable and unstable flow conditions. The saturation exponent remains constant at 1.94 when the flow is unstable for generalized Bond numbers less than -0.106

A Spatio-Temporal Bayesian Model for Estimating the Effects of Land Use Change on Urban Heat Island

The urban heat island (UHI) phenomenon has been identified and studied for over two centuries. As one of the most important factors, land use, in terms of both composition and configuration, strongly influences the UHI. As a result of the availability of detailed data, the modeling of the residual spatio-temporal autocorrelation of UHI, which remains after the land use effects have been removed, becomes possible. In this study, this key statistical problem is tackled by a spatio-temporal Bayesian hierarchical model (BHM). As one of the hottest areas in China, southwest China is chosen as our study area. Results from this study show that the difference of UHI levels between different cities in southwest China becomes large from 2000 to 2015. The variation of the UHI level is dominantly driven by temporal autocorrelation, rather than spatial autocorrelation. Compared with the composition of land use, the configuration has relatively minor influence upon UHI, due to the terrain in the study area. Furthermore, among all land use types, the water body is the most important UHI mitigation factor at the regional scale

Dental follicle cells rescue the regenerative capacity of periodontal ligament stem cells in an inflammatory microenvironment.

AIMS: Periodontal ligament stem cells (PDLSCs) are one of the best candidates for periodontal regeneration. Their function could be impaired in periodontitis microenvironment. Dental follicle cells (DFCs), serving as precursor cells and mesenchymal stem cells, have intimate connection with PDLSCs. However, it is still unknown whether DFCs could provide a favorable microenvironment to improve the proliferation and differentiation capacity of PDLSCs from healthy subjects (HPDLSCs) and patients diagnosed with periodontitis (PPDLSCs). METHODS: HPDLSCs, PPDLSCs and DFCs were harvested and identified using microscopic and flow cytometric analysis. Then, the coculture systems of DFCs/HPDLSCs and DFCs/PPDLSCs were established with 0.4 µm transwell, in which all the detection indexs were obtained from HPDLSCs and PPDLSCs. The expression of stemness-associated genes was detected by real-time PCR, and the proliferation ability was assessed using colony formation and cell cycle assays. The osteogenic differentiation capacity was evaluated by real-time PCR, western blot, ALP activity, Alizarin Red S staining and calcium level analysis, while the adipogenic differentiation capacity was determined by real-time PCR and Oil Red O staining. The cell sheet formation in vitro was observed by HE staining and SEM, and the implantation effect in vivo was evaluated using HE staining and Masson's trichrome staining. RESULTS: PPDLSCs had a greater proliferation capability but lower osteogenic and adipogenic potential than HPDLSCs. DFCs enhanced the proliferation and osteogenic/adipogenic differentiation of HPDLSCs and PPDLSCs to different degrees. Moreover, coculture with DFCs increased cell layers and extracellular matrix of HPDLSCs/PPDLSCs cell sheets in vitro and improved periodontal regeneration by HPDLSCs/PPDLSCs in vivo. CONCLUSIONS: Our data suggest that the function of PPDLSCs could be damaged in the periodontitis microenvironment. DFCs appear to enhance the self-renewal and multi-differentiation capacity of both HPDLSCs and PPDLSCs, which indicates that DFCs could provide a beneficial microenvironment for periodontal regeneration using PDLSCs

Discriminative transition sequences of origami metamaterials for mechano-logic

Transitions of multistability in structures have been exploited for various functions and applications, such as spectral gap tuning, impact energy trapping, and wave steering. However, a fundamental and comprehensive understanding of the transitions, either quasi-static or dynamic transitions, has not yet been acquired, especially in terms of the sequence predictability and tailoring mechanisms. This research, utilizing the stacked Miura-ori-variant (SMOV) structure that has exceptional multistability and shape reconfigurability as a platform, uncovers the deep knowledge of quasi-static and dynamic transitions, and pioneers the corresponding versatile formation and tuning of mechanical logic gates. Through theoretical, numerical, and experimental means, discriminative and deterministic quasi-static transition sequences, including reversible and irreversible ones, are uncovered, where they constitute a transition map that is editable upon adjusting the design parameters. Via applying dynamic excitations and tailoring the excitation conditions, reversible transitions between all stable configurations become attainable, generating a fully-connected transition map. Benefiting from the nonlinearity of the quasi-static and dynamic transitions, basic and compound mechanical logic gates are achieved. The versatility of the scheme is demonstrated by employing a single SMOV structure to realize different complex logic operations without increasing structural complexity, showing its superior computing power and inspiring the avenue for efficient physical intelligence.Comment: 26 pages, 5 figures, 8 supplementary figures, 2 supplementary table

Periodontal Ligament Stem Cells in the Periodontitis Microenvironment Are Sensitive to Static Mechanical Strain

During orthodontic treatment, periodontium remodeling of periodontitis patients under mechanical force was abnormal. We have previously confirmed the function impairment of periodontal ligament stem cells (PDLSCs) in the periodontitis microenvironment which might be involved in this pathological process. However, the response of PDLSCs in periodontitis microenvironment to mechanical force remains unclear. Therefore, in the present study, we introduced a Flexcell tension apparatus and investigated the response of PDLSCs obtained from periodontal tissues of periodontitis patients (PPDLSCs) and of those obtained from healthy periodontal tissues (HPDLSCs) to different magnitudes of static mechanical strain (SMS). PPDLSCs showed increased proliferation, decreased osteogenic activity, activated osteoclastogenesis, and greater secretion of inflammatory cytokines. Different magnitudes of SMS exerted distinct effects on HPDLSCs and PPDLSCs. An SMS of 12% induced optimal effects in HPDLSCs, including the highest proliferation, the best osteogenic ability, the lowest osteoclastogenesis, and the lowest secretion of inflammatory cytokines, while the optimal SMS for PPDLSCs was 8%. Excessive SMS damaged PPDLSCs function, including decreased proliferation, an imbalance between osteogenesis and osteoclastogenesis, and an activated inflammatory response. Our data suggest that PPDLSCs are more sensitive and less tolerant to SMS, and this may explain why mechanical force results in undesirable effects in periodontitis patients

Vacuole: a repository to control fruit flavor quality

The content of sugar and organic acid is the main factor that determines the fruit flavor quality and yield. More specifically, the ratio of sugar to organic acid affects the taste and nutritional value of fruits. Vacuoles and vacuolar transporters play pivotal roles in regulating fruit sugar and acid content, as most of the sugars and acids are transported and stored in ripe fruit vacuoles. In the past decades, the increasing vacuolar transporters or channels were reported to be involved in the sugars and acids' accumulation in horticultural fruits. This article specifically summarized the sugar, acid transporters and proton pumps that have been identified to be located in the vacuole membrane in horticultural crops, and described their physiological functions in the formation of flavor quality of main fruit crops in combination with their transport activities. Moreover, the research strategies and effective technical methods for functional analysis of vacuolar transporters were also discussed in this review