Complement C1q activates canonical Wnt signaling and promotes aging-related phenotypes.

Wnt signaling plays critical roles in development of various organs and pathogenesis of many diseases, and augmented Wnt signaling has recently been implicated in mammalian aging and aging-related phenotypes. We here report that complement C1q activates canonical Wnt signaling and promotes aging-associated decline in tissue regeneration. Serum C1q concentration is increased with aging, and Wnt signaling activity is augmented during aging in the serum and in multiple tissues of wild-type mice, but not in those of C1qa-deficient mice. C1q activates canonical Wnt signaling by binding to Frizzled receptors and subsequently inducing C1s-dependent cleavage of the ectodomain of Wnt coreceptor low-density lipoprotein receptor-related protein 6. Skeletal muscle regeneration in young mice is inhibited by exogenous C1q treatment, whereas aging-associated impairment of muscle regeneration is restored by C1s inhibition or C1qa gene disruption. Our findings therefore suggest the unexpected role of complement C1q in Wnt signal transduction and modulation of mammalian aging.

Inhibition of a novel Dickkopf-1-LDL receptor-related proteins 5 and 6 axis prevents diabetic cardiomyopathy in mice.

BACKGROUND AND AIMS: Anti-hypertensive agents are one of the most frequently used drugs worldwide. However, no blood pressure-lowering strategy is superior to placebo with respect to survival in diabetic hypertensive patients. Previous findings show that Wnt co-receptors LDL receptor-related proteins 5 and 6 (LRP5/6) can directly bind to several G protein-coupled receptors (GPCRs). Because angiotensin II type 1 receptor (AT1R) is the most important GPCR in regulating hypertension, this study examines the possible mechanistic association between LRP5/6 and their binding protein Dickkopf-1 (DKK1) and activation of the AT1R and further hypothesizes that the LRP5/6-GPCR interaction may affect hypertension and potentiate cardiac impairment in the setting of diabetes. METHODS: The roles of serum DKK1 and DKK1-LRP5/6 signalling in diabetic injuries were investigated in human and diabetic mice. RESULTS: Blood pressure up-regulation positively correlated with serum DKK1 elevations in humans. Notably, LRP5/6 physically and functionally interacted with AT1R. The loss of membrane LRP5/6 caused by injection of a recombinant DKK1 protein or conditional LRP5/6 deletions resulted in AT1R activation and hypertension, as well as ß-arrestin1 activation and cardiac impairment, possibly because of multiple GPCR alterations. Importantly, unlike commonly used anti-hypertensive agents, administration of the anti-DKK1 neutralizing antibody effectively prevented diabetic cardiac impairment in mice. CONCLUSIONS: These findings establish a novel DKK1-LRP5/6-GPCR pathway in inducing diabetic injuries and may resolve the long-standing conundrum as to why elevated blood DKK1 has deleterious effects. Thus, monitoring and therapeutic elimination of blood DKK1 may be a promising strategy to attenuate diabetic injuries.

Coverage-sensitive mechanism of electrochemical NO reduction on the SrTiO3(001) surface: a DFT investigation.

Due to its adverse environmental and human health hazards, addressing the elimination of nitric oxide (NO) has become a pressing concern for modern society. Currently, electrochemical NO reduction provides a new alternative to traditional selective catalytic reduction technology under mild reaction conditions. However, the complexity and variability of products make the coverage of NO an influencing factor that needs to be investigated. Hence, this study delves into the coverage-sensitive mechanism of electrochemical NO reduction on cost-effective perovskite catalysts, using SrTiO3 as an example, through density functional theory calculations. Phase diagrams analysis reveals that the coverage range from 0.25 to 1.00 monolayer (ML) coverage is favorable for NO adsorption. Gibbs free energy results indicate that the selectivity is significantly influenced by NO coverage. NH3 is likely to be generated at low coverage, while N2O and N2 are more likely to be produced at high coverage through a dimer mechanism. Charge analysis suggests that the charge transfer and Ti-O bond strength between reactants and catalysts are crucial factors. This work not only provides deep insights into coverage-sensitive reaction mechanisms but also is a guideline towards further rational design of high-performance perovskite catalysts.

Epigallocatechin-3-gallate promotes wound healing response in diabetic mice by activating keratinocytes and promoting re-epithelialization.

Type 2 diabetes (T2D) is a metabolic disorder that causes numerous complications including impaired wound healing and poses a significant challenge for the management of diabetic patients. Epigallocatechin-3-gallate (EGCG) is a natural polyphenol that exhibits anti-inflammatory and anti-oxidative benefits in skin wounds, however, the direct effect of EGCG on epidermal keratinocytes, the primary cells required for re-epithelialization in wound healing remains unknown. Our study aims to examine the underlying mechanisms of EGCG's ability to promote re-epithelialization and wound healing in T2D-induced wounds. Murine models of wound healing in T2D were established via feeding high-fat high-fructose diet (HFFD) and the creation of full-thickness wounds. Mice were administered daily with EGCG or vehicle to examine the wound healing response and underlying molecular mechanisms of EGCG's protective effects. Systemic administration of EGCG in T2D mice robustly accelerated the wound healing response following injury. EGCG induced nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2) and promoted cytokeratin 16 (K16) expression to activate epidermal keratinocytes and robustly promoted re-epithelialization of wounds in diabetic mice. Further, EGCG demonstrated high binding affinity with Kelch-like ECH-associated protein 1 (KEAP1), thereby inhibiting KEAP1-mediated degradation of NRF2. Our findings provide important evidence that EGCG accelerates the wound healing response in diabetic mice by activating epidermal keratinocytes, thereby promoting re-epithelialization of wounds via K16/NRF2/KEAP1 signaling axis. These mechanistic insights into the protective effects of EGCG further suggest its therapeutic potential as a promising drug for treating chronic wounds in T2D.

Registration study for the prevention and treatment of cerebral hemorrhage using naoxueshu oral liquid: Protocol for a research study.

BACKGROUND: Naoxueshu oral liquid is the only approved drug for acute treatment of cerebral hemorrhage in China. It has been used widely for the treatment of acute ischemic stroke and acute hemorrhagic stroke. However, safety and efficacy data on the early use of Naoxueshu oral liquid are lacking. The main purpose of this study is to observe the benefit and safety of early use of Naoxueshu oral liquid (< 72 h of cerebral hemorrhage) and offer evidence into the potential superiority of Naoxueshu oral liquid in patients with hemorrhagic stroke, and its healthcare costs. METHODS: This registration study for the prevention and treatment of cerebral hemorrhage using Naoxueshu oral liquid will be a quantitative, prospective, multicenter, observational clinical registry study. We aim to register 2000 patients with cerebral hemorrhage within 7 days of disease onset. This study will be an observational study and not interfere with the medication regimen of participants. Hence, we will not allocate patients. The main observation indicators will be the hematoma volume and the proportion of reduction 14 days post-cerebral hemorrhage (or at hospital discharge), onset of new stroke (ischemic stroke, hemorrhagic stroke) within 12 months of disease onset, independence in everyday life activities (modified Rankin Scale score ≤ 2), total cost during hospitalization, and treatment costs. CONCLUSION: This registration study will offer strong evidence for the efficacy and safety of Naoxueshu oral liquid for the prevention and treatment of cerebral hemorrhage, particularly with regard to early use (72 h after onset). It will offer evidence into the potential advantages of Naoxueshu oral liquid in patients with hemorrhagic stroke, including healthcare costs.

Long-read sequencing characterizes mitochondrial and plastid genome variants in Arabidopsis msh1 mutants.

The abundant repeats in plant mitochondrial genomes can cause rapid genome rearrangements and are also a major obstacle in short-read sequencing studies. Nuclear-encoded proteins such as MSH1 are known to suppress the generation of repeat-associated mitochondrial genome variants, but our understanding of these mechanisms has been constrained by the limitations of short-read technologies. Here, we used highly accurate long-read sequencing (PacBio HiFi) to characterize mitochondrial and plastid genome variants in Arabidopsis thaliana msh1 mutant individuals. The HiFi reads provided a global view of recombination dynamics with detailed quantification of parental and crossover recombination products for both large and small repeats. We found that recombination breakpoints were distributed relatively evenly across the length of repeated sequences and detected widespread internal exchanges of sequence variants between pairs of imperfect repeats in the mitochondrial genome of msh1 mutants. Long-read assemblies of mitochondrial genomes from seven other A. thaliana wild-type accessions differed by repeat-mediated structural rearrangements similar to those observed in msh1 mutants, but they were all in a simple low-heteroplasmy state. The Arabidopsis plastid genome generally lacks small repeats and exhibited a very different pattern of variant accumulation in msh1 mutants compared with the mitochondrial genome. Our data illustrate the power of HiFi technology in studying repeat-mediated recombination in plant organellar genomes and improved the sequence resolution for recombinational processes suppressed by MSH1. Plant organellar genomes can undergo rapid rearrangements. Long-read sequencing provides a detailed and quantitative view of mitochondrial and plastid genome variants normally suppressed by MSH1, advancing our understanding of plant organellar genome dynamics.

Strategies for improving the photocatalytic performance of metal-organic frameworks for CO2 reduction: A review.

Photocatalytic CO2 reduction is an appealing strategy for mitigating the environmental effects of greenhouse gases while simultaneously producing valuable carbon-neutral fuels. Numerous attempts have been made to produce effective and efficient photocatalysts for CO2 reduction. In contrast, the selection of competitive catalysts continues to be a substantial hindrance and a considerable difficulty in the development of photocatalytic CO2 reduction. It is vital to emphasize different techniques for building effective photocatalysts to improve CO2 reduction performance in order to achieve a long-term sustainability. Metal-organic frameworks (MOFs) are recently emerging as a new type of photocatalysts for CO2 reduction due to their excellent CO2 adsorption capability and unique structural characteristics. This review examines the most recent breakthroughs in various techniques for modifying MOFs in order to improve their efficiency of photocatalytic CO2 reduction. The advantages of MOFs using as photocatalysts are summarized, followed by different methods for enhancing their effectiveness for photocatalytic CO2 reduction via partial ion exchange of metal clusters, design of bimetal clusters, the modification of organic linkers, and the embedding of metal complexes. For integrating MOFs with semiconductors, metallic nanoparticles (NPs), and other materials, a number of different approaches have been also reviewed. The final section of this review discusses the existing challenges and future prospects of MOFs as photocatalysts for CO2 reduction. Hopefully, this review can stimulate intensive research on the rational design and development of more effective MOF-based photocatalysts for visible-light driven CO2 conversion.

Visible-light-induced photocatalytic CO2 reduction over zirconium metal organic frameworks modified with different functional groups.

The reduction of CO2 into high value-added chemicals and fuels by a photocatalytic technology can relieve energy shortages and the environmental problems caused by greenhouse effects. In the current work, an amino-functionalized zirconium metal organic framework (Zr-MOF) was covalently modified with different functional groups via the condensation of Zr-MOF with 2-pyridinecarboxaldehyde (PA), salicylaldehyde (SA), benzaldehyde (BA), and trifluoroacetic acid (TA), named Zr-MOF-X (X = PA, SA, BA, and TA), respectively, through the post-synthesis modification. Compared with Zr-MOF and Zr-MOF-TA, the introduction of PA, SA, or BA into the framework of Zr-MOF can not only enhance the visible-light harvesting and CO2 capture, but also accelerate the photogenerated charge separation and transfer, thereby improving the photocatalytic ability of Zr-MOF for CO2 reduction. These results indicate that the modification of Zr-MOF with electron-donating groups can promote the photocatalytic CO2 reduction. Therefore, the current work provides an instructive approach to improve the photocatalytic efficiency of CO2 reduction through the covalent modification of MOFs.

[Oral panorama reconstruction method based on pre-segmentation and Bezier function].

For patients with partial jaw defects, cysts and dental implants, doctors need to take panoramic X-ray films or manually draw dental arch lines to generate Panorama images in order to observe their complete dentition information during oral diagnosis. In order to solve the problems of additional burden for patients to take panoramic X-ray films and time-consuming issue for doctors to manually segment dental arch lines, this paper proposes an automatic panorama reconstruction method based on cone beam computerized tomography (CBCT). The V-network (VNet) is used to pre-segment the teeth and the background to generate the corresponding binary image, and then the Bezier curve is used to define the best dental arch curve to generate the oral panorama. In addition, this research also addressed the issues of mistakenly recognizing the teeth and jaws as dental arches, incomplete coverage of the dental arch area by the generated dental arch lines, and low robustness, providing intelligent methods for dental diagnosis and improve the work efficiency of doctors.

Reply to the Correspondence on "Crystalline Porous Organic Salt for Ultrarapid Adsorption/Desorption-Based Atmospheric Water Harvesting by Dual Hydrogen Bond System".

White et al., in a recent Correspondence, provided additional structural data to illustrate that CPOS-6 undergoes a single-crystal-to-single-crystal transformation during water adsorption/desorption. This finding gave a better understanding of the relevant experimental phenomena from the perspective of structural transformation and is a good complement to our previous results. However, we wish to emphasize that our research focuses on the kinetic behavior of water during ultrafast adsorption/desorption in nano-confined channels. Herein, we further interpret the rapid transport of water molecules in the nano-confined channels from the perspective of superfluidity.

Record Ultralarge-Pores, Low Density Three-Dimensional Covalent Organic Framework for Controlled Drug Delivery.

The unique structural characteristics of three-dimensional (3D) covalent organic frameworks (COFs) like high surface areas, interconnected pore system and readily accessible active sites render them promising platforms for a wide set of functional applications. Albeit promising, the reticular construction of 3D COFs with large pores is a very demanding task owing to the formation of interpenetrated frameworks. Herein we report the designed synthesis of a 3D non-interpenetrated stp net COF, namely TUS-64, with the largest pore size of all 3D COFs (47 Å) and record-low density (0.106 g cm-3 ) by reticulating a 6-connected triptycene-based linker with a 4-connected porphyrin-based linker. Characterized with a highly interconnected mesoporous scaffold and good stability, TUS-64 shows efficient drug loading and controlled release for five different drugs in simulated body fluid environment, demonstrating the competency of TUS-64 as drug nanocarriers.

The Diagnostic Role of Neurophysiological Tests for Premature Ejaculation: A Prospective Multicenter Study.

PURPOSE: Premature ejaculation (PE) is one of the most common male sexual dysfunctions. Local anesthetics (LAs) and dapoxetine are frequently used to treat PE; however, previous studies show variable efficacy. This study aims to determine the efficacy of LAs and dapoxetine using a novel classification based on neurophysiological tests. MATERIALS AND METHODS: This multicenter cohort study enrolled adult men (568) with an intravaginal ejaculatory latency time (IELT) ≤2 minutes. Patients were divided into 4 groups according to the results of neurophysiological tests and assigned different treatments for 12 weeks: 1) penile sensory hyperexcitability type (Sens)-LAs; 2) penile sympathetic hyperexcitability type (Symp)-dapoxetine; 3) mixed type (Mixed)-both LAs and dapoxetine; 4) normal type (Norm)-both LAs and dapoxetine. Self-estimated IELT and patient-reported outcomes were recorded. RESULTS: The total percentage of men achieving IELT >2 minutes and ≥5 minutes after treatment were 82.7% and 76.7%, respectively. For men with abnormal results of neurophysiological tests, 401 (86.6%) had improved IELT >2 minutes after the 12-week treatment course, in which 375 (81.0%) achieved IELT ≥5 minutes. All patient-reported outcome measures improved in each group after 12 weeks of treatment, with greater improvements among those with abnormal neurophysiological tests. CONCLUSIONS: The efficacy of LAs and dapoxetine increased in PE patients with abnormal results of neurophysiological tests. This novel classification of PE using neurophysiological tests could help guide and improve efficacy of PE therapies.

Copper-Promoted N-Alkylation and Bromination of Arylamines/Indazoles Using Alkyl Bromides as Reagents for Difunctionalization.

Practical copper-promoted N-alkylation and bromination of arylamines/indazoles with alkyl bromides are described; the N-alkylation-C-4-bromination and N-dialkylation-C-4-bromination of arylamines, and N-alkylation-C-3-bromination of indazoles, with alkyl bromides have been analyzed. The full use of alkyl bromides as alkylating and brominating building blocks without atom wastage, indicating excellent atom and step economy, has been highlighted. Eco-friendly oxygen and water are the reaction oxidant and byproduct, respectively.

Mechanism of Catalytic Transfer Hydrogenation for Furfural Using Single Ni Atom Catalysts Anchored to Nitrogen-Doped Graphene Sheets.

Catalytic transfer hydrogenation (CTH) of α,ß-unsaturated aldehydes using single metal atom catalysts supported on nitrogen-incorporated graphene sheet (M-Nx-Gr) materials has attracted increasing attention recently, yet the reaction mechanism remains to be explored. Compared to the Ni-N4-Gr model in which the dissociation of isopropanol is highly unfavorable as a result of steric hindrance and inertness of the Ni-N4 site embedded in graphene, the Ni-N3 site in Ni-N3-Gr is more active and facilitates the formation of *H with isopropanol as the H donor, where the dissociation of H from isopropanol with an energy barrier of 0.83 eV is the rate-determining step. An alternative reaction path starts from the coadsorption of isopropanol and furfural molecules at the Ni-N3 site, followed by a direct hydrogen transfer between the two molecules; however, the rate-determining step has a much higher energy barrier of 1.32 eV. Our calculations suggest that the hydrogenation of the aldehyde group is kinetically more favorable than the C═C hydrogenation, revealing the high chemoselectivity of furfural to furfuryl alcohol. Our investigations reveal that the CTH mechanism using the Ni-N3-Gr catalyst is different from that on traditional metal oxides, where the former has only one single active site, while two active sites are required for the latter. The proposed reaction mechanism of CTH for furfural in this study should be helpful to guide the design of single metal atom catalysts with appropriate N coordination for application in chemoselective hydrogenation reactions.

Theoretical understanding on all-solid frustrated Lewis pair sites of C2N anchored by single metal atom.

The design of all-solid heterogeneous catalysts with frustrated Lewis pairs (FLPs) has attracted much attention recently because of their appealing low dissociation energy for H2 molecules due to which a promotion of hydrogenation reaction is expected. The sterically encumbered Lewis acid (metal site) and base (nitrogen site) in the cavity of single transition metal atom-doped M/C2N sheets make them potential candidates for the design of catalysts with FLPs, while a comprehensive understanding of their intrinsic property and reactivity is still lacking. Calculations show that the complete dissociation of the H2 molecule into two H* states at the N sites requires two steps: heterolytic cleavage of the H2 molecule and the transfer of H* from the metal site to the N site, which are strongly related to the acidity of the metal site. Ni/C2N and Pd/C2N, which outperform the other eight transition metal atom (M) anchored M/C2N candidates, possess low energy barriers for the complete dissociation of H2 molecules, with values of only 0.30 and 0.20 eV, respectively. Furthermore, both Ni/C2N and Pd/C2N catalysts can achieve semi-hydrogenation of C2H2 into C2H4, with overall barriers of 0.81 and 0.75 eV, respectively, which are lower than those reported for many other catalysts. It is speculated that M/C2N catalysts with intrinsic FLPs may also find applications in other important hydrogenation reactions.

Nonlinear dynamics of discontinuous uncertain oscillators with unilateral constraints.

Nonlinear dynamics of discontinuous oscillators with unilateral constraints and non-random parametric uncertainties are investigated. Nonlinear oscillators considering single- and double-sided constraints are carefully constructed to exhibit rich bifurcations, such as period-doubling and Neimark-Sacker bifurcations. In deterministic amplitude-frequency responses, both hardening and softening effects are induced by non-smooth contact-type nonlinearities. Stabilities of the solutions are determined by the shooting method and the monodromy matrix. To effectively quantify the behaviors of nonlinear oscillators in the presence of parametric uncertainties, a non-intrusive surrogate function aided by arc-length ratio interpolation is constructed. Simulation results demonstrate variabilities of nonlinear responses under different non-random uncertainties. Moreover, an accuracy verification is provided to verify the effectiveness of the non-intrusive uncertainty propagation method. It is found that the surrogate function in combination with the arc-length ratio technique has high accuracy and evolutions of turning points are captured satisfactorily regardless of complex interactions of nonlinearities and uncertainties. The findings and methodologies reported are meaningful to general nonlinear systems having complex motions, paving the road for more in-depth investigations into uncertain nonlinear dynamics.

Molecular characterization, expression and interaction of MAPK, MAPKK and MAPKKK genes in upland cotton.

Mitogen-activated protein kinase (MAPK) signaling cascades, consisting of three types of sequentially phosphorylated kinases (MAPKKK, MAPKK, and MAPK), play vital roles in various processes including plant development and stress response. In this study, 52 GhMAPKs, 23 GhMAPKKs, and 166 GhMAPKKKs were identified in upland cotton. Chromosomal locations, gene duplication and structure, motifs, cis-regulatory elements, and protein subcellular localization were further analyzed. With the identified MAPK cascade genes in G. arboretum and G. raimondii, a syntenic diagram of three cotton species was constructed. The interactions of seven GhMAPK cascade genes were investigated. Two complete signaling modules were defined: The GhMEKK24/GhMEKK31-GhMAPKK9-GhMAPK10 and GhMEKK3/GhMEKK24/GhMEKK31-GhMAPKK16-GhMAPK10/GhMAPK11 cascades. Moreover, interaction networks and the interaction pairs were combined with their expression patterns and demonstrated that the network mediated by the MAPK signaling cascade participates in abiotic stress signaling. Our research provides a foundation for studying the molecular mechanism of the MAPK signaling pathway under abiotic stress.

A Non-Destructive Health Evaluation Method for Wooden Utility Poles with Frequency-Modulated Empirical Mode Decomposition and Laplace Wavelet Correlation Filtering.

Wooden utility poles are one of the most commonly used utility carriers in North America. Even though they are given different protection treatments, wooden utility poles are prone to have defects that are mainly caused by temperature, oxygen, moisture, and high potential hydrogen levels after decades of being exposed in open-air areas. In order to meet the growing demand regarding their maintenance and replacement, an effective health evaluation technology for wooden utility poles is essential to ensure normal power supply and safety. However, the commonly used hole-drilling inspection method always causes extra damage to wooden utility poles and the precision of health evaluation highly relies on technician experience at present. Therefore, a non-destructive health evaluation method with frequency-modulated empirical mode decomposition (FM-EMD) and Laplace wavelet correlation filtering based on dynamic responses of wooden utility poles was proposed in this work. Specifically, FM-EMD was used to separate multiple confusing closely-spaced vibration modes due to nonlinear properties of wooden utility poles into several single modes. The instantaneous frequency and damping factor of the decomposed signal of each single mode of the dynamic response of a wooden utility pole could be determined using Laplace wavelet correlation filtering with high precision. The health status of a wooden utility pole could then be estimated according to the extracted instantaneous frequency and damping factor of the decomposed signal of each single mode. The proposed non-destructive health evaluation method for wooden utility poles was tested in the field and achieved successful results.

Molecular Traits and Functional Exploration of BES1 Gene Family in Plants.

The BES1 (BRI1-EMSSUPPRESSOR1) gene family is a unique class of transcription factors that play dynamic roles in the Brassinosteroids (BRs) signaling pathway. The published genome sequences of a large number of plants provide an opportunity to identify and perform a comprehensive functional study on the BES1 gene family for their potential roles in developmental processes and stress responses. A total of 135 BES1 genes in 27 plant species were recognized and characterized, which were divided into five well-conserved subfamilies. BES1 was not found in lower plants, such as Cyanophora paradoxa and Galdieria sulphuraria. The spatial expression profiles of BES1s in Arabidopsis, rice, and cotton, as well as their response to abiotic stresses, were analyzed. The overexpression of two rice BES1 genes, i.e., OsBES1-3 and OsBES1-5, promotes root growth under drought stress. The overexpression of GhBES1-4 from cotton enhanced the salt tolerance in Arabidopsis. Five protein interaction networks were constructed and numerous genes co-expressed with GhBES1-4 were characterized in transgenic Arabidopsis. BES1 may have evolved in the ancestors of the first land plants following its divergence from algae. Our results lay the foundation for understanding the complex mechanisms of BES1-mediated developmental processes and abiotic stress tolerance.

Time-dependent efficacy and safety of tooth bleaching with cold plasma and H2O2 gel.

BACKGROUND: Hydrogen peroxide (H2O2) is the commonly used bleaching agent for teeth. But it is highly corrosive to teeth for the high concentration. The cold atmospheric pressure plasma has been witnessed a novel tooth bleaching technology and could help strengthen the bleaching effect when combined with H2O2. However, the efficacy and safety might highly correlated with processing time. The present study aims to evaluate the time-dependent efficacy and safety of tooth bleaching with cold plasma and H2O2 gel in vitro. METHODS: The H2O2 concentrations of the gel used in the study are 6%, 15%, 25% and 35%, respectively and the treatment time varies from 5 to 20 min. The tooth bleaching effect was evaluated by a Crystaleye Spectrophotometer and the overall change of the colorimetric value based on three independent measurements. Meanwhile, the microhardness, roughness and tooth temperature were evaluated. The surface morphology and the elemental composition were determined by scanning electron microscope and energy-dispersive X-ray spectroscopy. RESULTS: 5 min bleaching treatment contributed to 60% of the bleaching effect maximum, the 10 min effect was close to 15 min effect. Meanwhile, the microhardness reduced and roughness increased under a treatment which was longer than 20 min. Tooth pulp chamber temperature was keeping in a safe range within 20 min treatment. CONCLUSION: 5-10 min was the best treatment time from which we can get an ideal tooth bleaching effect and less influence on tooth enamel and pulp tissue when using cold plasma and H2O2 gel.