Controllable synthesis of borophene aerogels by utilizing h-BN layers for high-performance next-generation batteries.

Borophene is emerging as a promising electrode material for Li, Na, Mg, and Ca ion batteries due to its anisotropic Dirac properties, high charge capacity, and low energy barrier for ion diffusion. However, practical synthesis of active and stable borophene remains challenging in producing electrochemical devices. Here, we introduce a method for borophene aerogels (BoAs), utilizing hexagonal boron nitride aerogels. Borophene grows between h-BN layers utilizing boron-boron bridges, as a nucleation site, where borophene forms monolayers mixed with sp2-sp3 hybridization. This versatile method produces stable BoAs and is compatible with various battery chemistries. With these BoAs, we accomplish an important milestone to successfully fabricate high-performance next-generation batteries, including Na-ion (478 mAh g-1, at 0.5C, >300 cycles), Mg-ion (297 mAh g-1, at 0.5C, >300 cycles), and Ca-ion (332 mAh g-1, at 0.5C, >400 cycles), and Li-S batteries, with one of the highest capacities to date (1,559 mAh g-1, at 0.3C, >1,000 cycles).

Simulation and experimental study on the degradation of the greenhouse gas SF6 by thermal plasma.

SF6 gas is widely used on many occasions especially in the power equipment, but it has been restricted since Kyoto Protocol as the strongest greenhouse gas. To reduce the SF6 emission, several methods are now used such the recycling & purification and the SF6 degradation. Considering the huge market of SF6 and the recent demand in the field of power equipment, it is necessary to explore new ways to thoroughly destroy SF6. This work brought out the idea to degrade retired SF6 by thermal plasma. A simplified kinetic model was established to predict the feasibility of this idea as well as the degradation products of SF6, and then the prototype of SF6 degradation by thermal plasma was built and tested. In thermal plasma, SF6 gradually decomposed into atoms, and then H2 was added to capture the released F atoms to generate HF and also prevent the association reactions of SF6. In order to achieve the desired degradation effect, the reaction temperature and the mixing ratio of H2 should be sufficiently high. However, excessive H2 could generate the H2S, and excessive discharge power could decrease the energy yield. When the flow rate of SF6/H2 was set as 8/30 L/min and the discharge current was set as 100A, the destruction removal efficiency (DRE) of SF6 was 99.0% and the energy yield was 206 g/kWh. This work also discusses how to further treat the by-products such as HF and S from this prototype effectively.

Artificial intelligence-assisted determination of available sites for palatal orthodontic mini implants based on palatal thickness through CBCT.

OBJECTIVES: To develop an artificial intelligence (AI) system for automatic palate segmentation through CBCT, and to determine the personalized available sites for palatal mini implants by measuring palatal bone and soft tissue thickness according to the AI-predicted results. MATERIALS AND METHODS: Eight thousand four hundred target slices (from 70 CBCT scans) from orthodontic patients were collected, labelled by well-trained orthodontists and randomly divided into two groups: a training set and a test set. After the deep learning process, we evaluated the performance of our deep learning model with the mean Dice similarity coefficient (DSC), average symmetric surface distance (ASSD), sensitivity (SEN), positive predictive value (PPV) and mean thickness percentage error (MTPE). The pixel traversal method was proposed to measure the thickness of palatal bone and soft tissue, and to predict available sites for palatal orthodontic mini implants. Then, an example of available sites for palatal mini implants from the test set was mapped. RESULTS: The average DSC, ASSD, SEN, PPV and MTPE for the segmented palatal bone tissue were 0.831%, 1.122%, 0.876%, 0.815% and 6.70%, while that for the palatal soft tissue were 0.741%, 1.091%, 0.861%, 0.695% and 12.2%, respectively. Besides, an example of available sites for palatal mini implants was mapped according to predefined criteria. CONCLUSIONS: Our AI system showed high accuracy for palatal segmentation and thickness measurement, which is helpful for the determination of available sites and the design of a surgical guide for palatal orthodontic mini implants.

Characteristics of oral microbiota and oral health in the patients treated with clear aligners: a prospective study.

OBJECTIVES: In this prospective clinical study, the effect of clear aligners on periodontal health and oral hygiene was examined. As the same time, microbial changes of the aligner tray and subgingival microbiota community were investigated. METHODS: The study recruited fifteen patients, and clinical parameters were recorded at three different time points: before the initiation of aligner treatment (T0), 1 month after treatment onset (T1), and 3 months after treatment onset (T3). Plaque samples were collected from the inner surface of aligners and subgingival sulcus at each of these time points. The microbial composition of the samples was analyzed using 16S rRNA gene sequencing, and changes were evaluated based on the abundance of amplicon sequence variants (ASVs). RESULTS: Reduction in plaque index and improvement in periodontal health were observed. In aligner tray plaque samples, the relative abundance of Streptococcus increased significantly, as well as the richness and diversity of microbiota decreased substantially as the duration of treatment time. In subgingival plaque samples, alpha and beta diversity of microbiota did not change significantly. CONCLUSIONS: During the clear aligner treatment, the patients' periodontium remained in a healthy condition, and clear aligner treatment had no significant impact on the composition of subgingival microbiota. The structure of the aligner tray microbiota altered significantly at both phylum and genus levels and attracted a unique and less diverse microbiota community. CLABSINABSICAL RELEVANCE: Clear aligner treatment has no significant impact on periodontal health and subgingival microbiota composition of patients.

The effects of aligner anchorage preparation on mandibular first molars during premolar-extraction space closure with clear aligners: A finite element study.

INTRODUCTION: This study aimed to determine the effectiveness of different aligner anchorage preparations on mandibular first molars during premolar-extraction space closure with clear aligners and to assess the effects of different modes of Class II elastics on mandibular first molars. METHODS: Finite element models were constructed on the basis of cone-beam computed tomography data from an orthodontic patient. The models comprised maxilla, mandible, maxillary and mandibular teeth without first premolars, periodontal ligaments, attachments and aligners. Tooth displacement tendencies were calculated using different aligner anchorage preparations and Class II elastics on the models from the same patient. Three group sets were designed on the basis of the positions of aligner cutouts and buttons (mesiobuccal, distobuccal and lingual). Four groups were established in each of the 3 group sets. Four groups were created: (1) no elastic traction + no anchorage preparation, (2) anchorage preparation only, (3) elastic traction only, and (4) elastic traction + anchorage preparation. Different aligner anchorage preparations (0°, 1°, 2°, 3°) were applied on mandibular second premolars and molars. The Class II traction force was set to 100 g. RESULTS: With clear aligners, mandibular first molars were subject to mesial tipping, lingual tipping and intrusion. In the condition of no elastic traction, aligner anchorage preparation resulted in distal tipping, buccal tipping, and extrusion effect on mandibular first molars. Aligner anchorage preparation was more effective in the distal and lingual cutout groups than in the mesial cutout group. In the condition of Class II elastic traction, the bodily movement of mandibular first molars was achieved with a 3° anchorage preparation for the mesial cutout group and a 1.7° anchorage preparation for distal and lingual cutout groups. Absolute maximal anchorage was achieved with a 2° anchorage preparation for distal and lingual cutout groups. CONCLUSIONS: Clear aligner therapy caused mesial tipping, lingual tipping and intrusion of mandibular first molars during premolar-extraction space closure. Aligner anchorage preparation effectively prevented mesial and lingual tipping of mandibular molars. Distal and lingual cutout modes were more effective than mesial cutout modes in aligner anchorage preparation. For each aligner stage (0.25 mm), 1.7° aligner anchorage preparation and Class II elastics with distal or lingual cutouts led to the bodily movement of mandibular first molars, whereas 2° anchorage preparation reached absolute maximal anchorage.

Comparison of three-dimensional maxillary growth across spheno-occipital synchondrosis maturation stages.

BACKGROUND: This study aimed to three-dimensionally compare the maxillary growth among the spheno-occipital synchondrosis (SOS) maturation stages in both genders. METHODS: This is a cross-sectional study of a retrospective type in which cone-beam computed tomography (CBCT) images of 500 patients aged 6 to 25 years (226 males and 274 females) were analyzed. The SOS was evaluated using the four-stage scoring system; completely open, partially fused, semi-fused, or completely fused. The SOS scoring and three-dimensional cephalometric measurements were analyzed by Invivo 6.0.3 software. Descriptive and analytical statistics were performed and a P-value < 0.05 was considered statistically significant. RESULTS: There was a statistically significant difference in maxillary measurements among SOS maturation stages in both genders (P < 0.05). The mean differences in the maxillary growth among the SOS maturation stages between SOS stages 2 and 3 were higher than those between stages 1and 2 and stages 3 and 4 for maxillary length and height in both genders. However, the mean difference in the maxillary width was higher between SOS stages 1 and 2 than those stages 2 and 3 and stages 3 and 4. On other hand, there may be lesser maxillary growth between SOS stages 3 and 4 for maxillary width, length (in males), and height. The growth curves showed high active growth of the maxilla as the SOS was still fusing (especially stage 2 and 3) than those of the fused (stage 4). Moreover, the acceleration of growth occurred earlier in females than males regarding chronological age but not for SOS maturation stages. CONCLUSIONS: The SOS maturation stages are valid and reliable maxillary skeletal maturation indicators for three-dimensional maxillary growth in both genders.

Identifying carbon as the source of visible single-photon emission from hexagonal boron nitride.

Single-photon emitters (SPEs) in hexagonal boron nitride (hBN) have garnered increasing attention over the last few years due to their superior optical properties. However, despite the vast range of experimental results and theoretical calculations, the defect structure responsible for the observed emission has remained elusive. Here, by controlling the incorporation of impurities into hBN via various bottom-up synthesis methods and directly through ion implantation, we provide direct evidence that the visible SPEs are carbon related. Room-temperature optically detected magnetic resonance is demonstrated on ensembles of these defects. We perform ion-implantation experiments and confirm that only carbon implantation creates SPEs in the visible spectral range. Computational analysis of the simplest 12 carbon-containing defect species suggest the negatively charged [Formula: see text] defect as a viable candidate and predict that out-of-plane deformations make the defect environmentally sensitive. Our results resolve a long-standing debate about the origin of single emitters at the visible range in hBN and will be key to the deterministic engineering of these defects for quantum photonic devices.

FISI: frequency domain integration sequential imaging at 1.26×1013 frames per second and 108 lines per millimeter.

High spatial resolution on the image plane (intrinsic spatial resolution) has always been a problem for ultrafast imaging. Single-shot ultrafast imaging methods can achieve high spatial resolution on the object plane through amplification systems but with low intrinsic spatial resolutions. We present frequency domain integration sequential imaging (FISI), which encodes a transient dynamic by an inversed 4f (IFF) system and decodes it using optical spatial frequencies recognition (OFR), which overcomes the limitation of the spatial frequencies recognition algorithm. In an experiment on the process of an air plasma channel, FISI achieved shadow imaging of the channel with a framing rate of 1.26×1013 fps and an intrinsic spatial resolution of 108 lp/mm (the spatial resolution on the image plane). Owing to its excellent framing time and high intrinsic spatial resolution, FISI can probe both repeatable and unrepeatable ultrafast phenomena, such as laser-induced damage, plasma physics, and shockwave interactions in living cells with high quality.

Molecular mechanism in trigeminal nerve and treatment methods related to orthodontic pain.

BACKGROUND: Orthodontic treatment is the main treatment approach for malocclusion. Orthodontic pain is an inevitable undesirable adverse reaction during orthodontic treatment. It is reported orthodontic pain has become one of the most common reason that patients withdraw from orthodontic treatment. Therefore, understanding the underlying mechanism and finding treatment of orthodontic pain are in urgent need. AIMS: This article aims to sort out the mechanisms and treatments of orthodontic pain, hoping to provide some ideas for future orthodontic pain relief. MATERIALS: Tooth movement will cause local inflammation. Certain inflammatory factors and cytokines stimulating the trigeminal nerve and further generating pain perception, as well as drugs and molecular targeted therapy blocking nerve conduction pathways, will be reviewed in this article. METHOD: We review and summaries current studies related to molecular mechanisms and treatment approaches in orthodontic pain control. RESULTS: Orthodontics pain related influencing factors and molecular mechanisms has been introduced. Commonly used clinical methods in orthodontic pain control has been evaluated. DISCUSSION: With the clarification of more molecular mechanisms, the direction of orthodontic pain treatment will shift to targeted drugs.

NGF-Induced Upregulation of CGRP in Orofacial Pain Induced by Tooth Movement Is Dependent on Atp6v0a1 and Vesicle Release.

The nerve growth factor (NGF) and calcitonin gene-related peptide (CGRP) play a crucial role in the regulation of orofacial pain. It has been demonstrated that CGRP increases orofacial pain induced by NGF. V-type proton ATPase subunit an isoform 1 (Atp6v0a1) is involved in the exocytosis pathway, especially in vesicular transport in neurons. The objective was to examine the role of Atp6v0a1 in NGF-induced upregulation of CGRP in orofacial pain induced by experimental tooth movement. Orofacial pain was elicited by ligating closed-coil springs between incisors and molars in Sprague-Dawley rats. Gene and protein expression levels were determined through real-time polymerase chain reaction, immunostaining, and fluorescence in situ hybridization. Lentivirus vectors carrying Atp6v0a1 shRNA were used to knockdown the expression of Atp6v0a1 in TG and SH-SY5Y neurons. The release of vesicles in SH-SY5Y neurons was observed by using fluorescence dye FM1-43, and the release of CGRP was detected by Enzyme-Linked Immunosorbent Assy. Orofacial pain was evaluated through the rat grimace scale. Our results revealed that intraganglionic administration of NGF and Atp6v0a1 shRNA upregulated and downregulated CGRP in trigeminal ganglia (TG) and trigeminal subnucleus caudalis (Vc), respectively, and the orofacial pain was also exacerbated and alleviated, respectively, following administration of NGF and Atp6v0a1 shRNA. Besides, intraganglionic administration of NGF simultaneously caused the downregulation of Atp6v0a1 in TG. Moreover, the release of vesicles and CGRP in SH-SY5Y neurons was interfered by NGF and Atp6v0a1 shRNA. In conclusion, in the orofacial pain induced by experimental tooth movement, NGF induced the upregulation of CGRP in TG and Vc, and this process is dependent on Atp6v0a1 and vesicle release, suggesting that they are involved in the transmission of nociceptive information in orofacial pain.

The effects of aligner overtreatment on torque control and intrusion of incisors for anterior retraction with clear aligners: A finite-element study.

INTRODUCTION: The objective of this study was to analyze the effects of aligner overtreatment on torque control and intrusion of incisors for anterior retraction with clear aligners. METHODS: Models including a maxillary dentition without first premolars, maxilla, periodontal ligaments, attachments, and aligners were constructed and imported to finite-element software. Two groups of models were created: (1) without canine attachment and (2) with canine attachment. Overtreatment degrees (0°, 1°, 2°, 3°, 4°, and 5°) were applied for both groups. RESULTS: Clear aligner therapy caused lingual tipping and extrusion of incisors, distal tipping and extrusion of canines, and mesial tipping and intrusion of posterior teeth, which was more significant with canine attachments except for second premolars. Aligner overtreatment produced palatal root torquing and intrusion of incisors, distal tipping of canines, and mesial tipping of second premolars, with more significant in the condition with canine attachments. With canine attachments, 1.2° overtreatment could cause bodily retraction of central incisors. Without overtreatment, stress was concentrated on apical and cervical area of both labial and lingual surfaces of periodontal ligaments. The stress value was higher with canine attachments. However, when overtreatment was added, the stress was distributed more evenly. CONCLUSIONS: Clear aligner therapy produced lingual tipping and extrusion of incisors during anterior retraction. Overtreatment can achieve incisor intrusion and palatal root torquing, and the effect could be augmented by adding attachments on canines, which required more anchorage from posterior teeth. Appropriate overtreatment with placing attachments on canines should be designed to ensure bodily retraction and the least root resorption.

Quantitative analysis of facial symmetry by using three-dimensional technology.

BACKGROUND: Facial symmetry is becoming increasingly important in today's orthodontic treatment. But the asymmetrical boundary is not clearly demarcated. Stereophotogrammetry has a clear advantage in measuring facial asymmetry. The aim of this study was to quantify the facial asymmetry by three-dimensional (3D) technology as well as to study whether the evaluation by non-experts about facial asymmetry was consistent with the analysis by 3D technology. METHODS: The facial symmetry of 330 patients was evaluated by 10 non-experts. 3D facial images were taken using 3dMD stereophotogrammetry equipment. The original face and its mirror shell were divided into 7 regions and the surface matching was measured in the whole face and all regional areas. The degree of symmetry was calculated by the software 3-matic STL 9.0. The difference between the two groups was analyzed by Independent-Samples T Test and the diagnostic efficiency of symmetry degree was analyzed by ROC curve analysis. The consistency between the symmetric degree and the result of evaluation was analyzed by Pearson correlation analysis. RESULTS: The ROC analysis revealed significant diagnostic values in the determination of the facial asymmetry of lip, chin, cheek and lateral mandible areas. The cut-off values of symmetry degree were between 60 and 80%. The evaluation was middle correlation with the symmetric degree of the whole face. CONCLUSIONS: The chin and lateral mandible contribute most significantly to the facial symmetry. The objective measurement of facial symmetry, 3D technology, is reliable.

Is the response rate of oral appliance therapy for subjects with and without position-dependent obstructive sleep apnoea different?

Objective To compare the effect of oral appliance (OA) treatment on non-position-dependent obstructive sleep apnoea (non-POSA) and position-dependent obstructive sleep apnoea (POSA).Methods The investigational sample was 205 patients with obstructive sleep apnoea at baseline and they were classified as non-POSA and POSA. Polygraphic registration was employed to compare the proportion of treatment responders between non-POSA and POSA groups at eight-week and one-year follow-ups. The treatment responder was defined as apnoea-hypopnoea index (AHI) <10 and/or ≥50% reduction in AHI.Results At the eight-week follow-up, the proportions of responders were 56% and 69% for the non-POSA and POSA groups (not significant), respectively. The responder proportions were increased to 68% and 77% for the two groups, respectively, at the one-year follow-up (not significant between the two groups). At the two follow-ups, there was no significant difference in absolute change in overall AHI between the two groups. However, the decrease in supine AHI was significantly greater in the POSA group, while the decrease in non-supine AHI was significantly greater in the non-POSA group.Conclusions The response rate for OA treatment did not differ between POSA and non-POSA groups. However, greater decreases in supine AHI and non-supine AHI were found among POSA and non-POSA patients, respectively.

m6A regulator-mediated RNA methylation modification patterns are involved in immune microenvironment regulation of periodontitis.

The role of epigenetic regulation in immunity is emerging, especially for RNA N6-methyladenosine (m6A) modification. However, little is known about the role of m6A in the regulation of the immune microenvironment of periodontitis. Thus, we aim to investigate the impact of m6A modification in periodontitis immune microenvironment. The RNA modification patterns mediated by 23 m6A-regulators were systematically evaluated in 310 periodontitis samples. The impact of m6A modification on immune microenvironment characteristics was explored, including infiltrating immunocytes, immune reaction gene-sets and HLAs (human leukocyte antigen) gene. m6A phenotype-related immune genes were also identified. 17 m6A regulators were dysregulated and a 15-m6A regulator signature can well distinguish periodontitis and control samples. ALKBH5 and FMR1 are closely related to infiltrating monocyte abundance. ELAVL1 and CBLL1 are significant regulators in immune reaction of TNF_Family_Members_Receptors and Cytokine. The expression of HLA-B and HLA-DOA is affected by ALKBH5 and LRPPRC. 3 distinct RNA modification patterns mediated by 23 m6A regulators were identified. They differ from immunocyte abundance, immune reaction and HLA gene. 1631 m6A phenotype-related genes and 70 m6A-mediated immune genes were identified, and the biological functions of these were explored. Our finding demonstrated the m6A modification plays a crucial role in the diversity and complexity of the immune microenvironment of periodontitis.

N/OFQ modulates orofacial pain induced by tooth movement through CGRP-dependent pathways.

BACKGROUND: Nociceptin/orphanin FQ (N/OFQ) has been revealed to play bidirectional roles in orofacial pain modulation. Calcitonin gene-related peptide (CGRP) is a well-known pro-nociceptive molecule that participates in the modulation of orofacial pain. We aimed to determine the effects of N/OFQ on the modulation of orofacial pain and on the release of CGRP. METHODS: Orofacial pain model was established by ligating springs between incisors and molars in rats for the simulation of tooth movement. The expression level of N/OFQ was determined and pain level was scored in response to orofacial pain. Both agonist and antagonist of N/OFQ receptor were administered to examine their effects on pain and the expression of CGRP in trigeminal ganglia (TG). Moreover, gene therapy based on the overexpression of N/OFQ was delivered to validate the modulatory role of N/OFQ on pain and CGRP expression. RESULTS: Tooth movement elicited orofacial pain and an elevation in N/OFQ expression. N/OFQ exacerbated orofacial pain and upregulated CGRP expression in TG, while UFP-101 alleviated pain and downregulated CGRP expression. N/OFQ-based gene therapy was successful in overexpressing N/OFQ in TG, which resulted in pain exacerbation and elevation of CGRP expression in TG. CONCLUSIONS: N/OFQ exacerbated orofacial pain possibly through upregulating CGRP.

The Effects of Static Magnetic Field on Orthodontic Tooth Movement in Mice.

The application of static magnetic field (SMF) has been considered an effective and noninvasive method to accelerate orthodontic tooth movement. The objective of this study was to explore the effects of SMF on orthodontic tooth movement in mice. A total of 105 Balb/c mice (body mass: 25-30 g) were divided into experimental group (SMF + force, 48), control group (force only, 48), and blank group (neither SMF nor force, 9). After the placement of orthodontic appliances, the experimental group was exposed to the SMF environment generated by Neodymium-iron-boron (NdFeB) magnets with an intensity of 20-204 mT. At 1, 3, 7, 14, 21, and 28 days after appliance insertion, eight animals in both experimental and control groups were sacrificed and the left maxillae were dissected to measure the distance of tooth movement, respectively. Meanwhile, the width of periodontal ligament (PDL), length of hyalinized zone, and the number of osteoclasts were evaluated by hematoxylin-eosin and tartrate-resistant acid phosphatase staining. We finally found that the experimental group demonstrated an enhanced rate and greater cumulative amount of tooth movement than the control group (0.2887 ± 0.0041 mm vs. 0.2114 ± 0.0089 mm, P < 0.05). On Days 7, 14, and 28, the experimental group also displayed a significantly greater width of PDL. Earlier formation and removal of the hyalinized zone, and significantly more osteoclasts were observed in the experimental group as well. The results suggested that SMF may be a promising nonsurgical intervention to accelerate orthodontic tooth movement. © 2021 Bioelectromagnetics Society.

Placebo modulation in orthodontic pain: a single-blind functional magnetic resonance study.

OBJECTIVES: The mechanism of orthodontic pain modulation with a placebo remains largely unknown. This study aimed to investigate the placebo modulation of brain activity associated with orthodontic pain using functional magnetic resonance imaging (fMRI). METHODS: This longitudinal fMRI experiment recruited 23 volunteers and a self-contrast method was used. At first time, the participants were scanned without placebo (first period), followed by a 30-day washout, the participants were scanned again with placebo administration (second period). Orthodontic pain was caused by orthodontic separators placement between the lower right molars for both two periods. 24 h after placement, the MRI scans were taken, including a bite/non-bite task fMRI and a resting-state fMRI. A generalized linear model was used to identify pain-regulating network from task fMRI. Functional connectivity analysis of pain-related brain regions was performed to study the placebo effect on connectivity of pain-regulating networks using resting-state fMRI. RESULTS: The results of brain activation patterns were largely similar under placebo and non-placebo conditions. Under the non-placebo condition, the activities in multiple brain regions, including the pre-central gyrus, superior frontal gyrus, superior parietal lobule, and supramarginal gyrus, were significantly higher than that of the placebo condition. However, the anterior cingulate cortex (ACC) was activated under the non-placebo condition but not in the placebo one. The functional connectivities between ACC and orbitofrontal cortex, and the dorsolateral prefrontal cortex and orbitofrontal cortex were reduced under placebo condition. CONCLUSION: Participants demonstrated similar brain activation patterns for orthodontic pain with or without placebos. With placebo, reduced activation in primary sensory cortex and decreased activation in ACC indicated that ACC could be fundamental in analgesia.

High-Performance Atomically-Thin Room-Temperature NO2 Sensor.

The development of room-temperature sensing devices for detecting small concentrations of molecular species is imperative for a wide range of low-power sensor applications. We demonstrate a room-temperature, highly sensitive, selective, stable, and reversible chemical sensor based on a monolayer of the transition-metal dichalcogenide Re0.5Nb0.5S2. The sensing device exhibits a thickness-dependent carrier type, and upon exposure to NO2 molecules, its electrical resistance considerably increases or decreases depending on the layer number. The sensor is selective to NO2 with only minimal response to other gases such as NH3, CH2O, and CO2. In the presence of humidity, not only are the sensing properties not deteriorated but also the monolayer sensor shows complete reversibility with fast recovery at room temperature. We present a theoretical analysis of the sensing platform and identify the atomically sensitive transduction mechanism.

Peanut Shell Derived Carbon Combined with Nano Cobalt: An Effective Flame Retardant for Epoxy Resin.

Biomass-derived carbon has been recognised as a green, economic and promising flame retardant (FR) for polymer matrix. In this paper, it is considered that the two-dimensional (2D) structure of carbonised peanut shells (PS) can lead to a physical barrier effect on polymers. The carbonised sample was prepared by the three facile methods, and firstly adopted as flame retardants for epoxy resin. The results of thermal gravimetric analysis (TGA) and cone calorimeter tests indicate that the carbon combined with nano Cobalt provides the most outstanding thermal stability in the current study. With 3 wt.% addition of the FR, both peak heat release rate (pHRR) and peak smoke production rate (PSPR) decrease by 37.9% and 33.3%, correspondingly. The flame retardancy mechanisms of the FR are further explored by XPS and TG-FTIR. The effectiveness of carbonised PS can be mainly attributed to the physical barrier effect derived by PS's 2D structure and the catalysis effect from Cobalt, which contribute to form a dense char layer.

A comparison of resin infiltration and microabrasion for postorthodontic white spot lesion.

INTRODUCTION: The objective of this research was to evaluate and compare the effectiveness of microabrasion and resin infiltration for white spot lesions (WSLs). METHODS: Patients with postorthodontic WSLs were enrolled and randomly assigned to the control, microabrasion, and resin-infiltration groups. Intraoral photographs were taken before and after (6 months later) treatment. WSL sizes were determined through ImageJ (Wayne Rasband, Kensington, Md). Integrated optical density (IOD) was determined for a WSL and its surrounding normal enamel through Image-Pro Plus (version 6.0; Media Cybernetics, Rockville, Md), and their differences of IOD were considered as the IOD surrogate for that WSL. The color change of WSL were measured through ΔE. RESULTS: A total of 27 eligible patients were enrolled; 9 subjects were assigned to each group, resulting in 56 teeth in the control group, 72 in the microabrasion group, and 58 in the resin-infiltration group. The ratios of WSL size (after/before) were similar between the microabrasion and resin-infiltration group (43.94 ± 0.03% vs 45.02 ± 0.03%; P = 0.96 > 0.05), but those of the 2 groups were significantly lower than those of the control group (92.15 ± 0.02%) (P <0.001). Moreover, the ratios of IOD (after/before) were significantly lower in the resin-infiltration group (22.94 ± 0.02%) than in the microabrasion (78.11 ± 0.03%) and control (83.79 ± 0.02%) (P <0.001) groups. The highest ΔE improvement was obtained by infiltration, but there was no significant difference between microabrasion and control group. CONCLUSIONS: Resin infiltration and microabrasion are comparably effective in reducing the sizes of WSL, but resin infiltration enjoys an esthetic advantage over microabrasion.