Advanced Dielectric Materials for Triboelectric Nanogenerators: Principles, Methods, and Applications.

Triboelectric nanogenerator (TENG) manifests distinct advantages such as multiple structural selectivity, diverse selection of materials, environmental adaptability, low cost, and remarkable conversion efficiency, which becomes a promising technology for micro-nano energy harvesting and self-powered sensing. Tribo-dielectric materials are the fundamental and core components for high-performance TENGs. In particular, the charge generation, dissipation, storage, migration of the dielectrics, and dynamic equilibrium behaviors determine the overall performance. Herein, a comprehensive summary is presented to elucidate the dielectric charge transport mechanism and tribo-dielectric material modification principle toward high-performance TENGs. The contact electrification and charge transport mechanism of dielectric materials is started first, followed by introducing the basic principle and dielectric materials of TENGs. Subsequently, modification mechanisms and strategies for high-performance tribo-dielectric materials are highlighted regarding physical/chemical, surface/bulk, dielectric coupling, and structure optimization. Furthermore, representative applications of dielectric materials based TENGs as power sources, self-powered sensors are demonstrated. The existing challenges and promising potential opportunities for advanced tribo-dielectric materials are outlined, guiding the design, fabrication, and applications of tribo-dielectric materials.

Effects of exercise therapy on anxiety and depression in patients with COVID-19: a systematic review and meta-analysis.

Objective: With increasing rates of anxiety and depression during COVID-19, exercise treatment has drawn attention for its effects on COVID-19 patients with anxiety and depression. This study set out to assess the impact of exercise therapy on COVID-19 patients' anxiety and depression. Methods: PubMed, EMBASE, Web of Science and Cochrane Library were used to search articles about exercise therapy as a means of treating anxiety and depression in COVID-19 patients from inception to April 30, 2023. The risk of bias was assessed by the Cochrane Collaboration bias risk tool. Data were pooled with the random effects model. RevMan version 5.4 was used for the statistical analyses. This work was registered in the PROSPERO database (registration number: CRD42023406439). Selection criteria: Randomized clinical trials (RCTs) of COVID-19 patients with anxiety and depression were included to assess the impact of physical exercise on COVID-19 patients with anxiety and depression. Results: 6 studies including a total of 461 COVID-19 patients were analyzed in this meta-analysis. Overall, the meta-analysis showed that compared with the control group, exercise could significantly improve anxiety (SMD = -0.76; 95%CI: -0.96, -0.55; p < 0.00001), depression level (SMD = -0.39; 95%CI: -0.70, -0.09; p = 0.01), the PHQ-9 score (MD = -1.82; 95%CI: -2.93, -0.71; p = 0.001) and the sleep quality (SMD = -0.73; 95%CI: -1.32, -0.14; p = 0.01) in COVID-19 patients. Conclusion: The research provided evidence that exercise therapy is able to help COVID-19 patients experience less anxiety and depression and have better-quality sleep. Systematic review registration: CRD42023406439.

Effect of Hyperthermal Hybrid Gas Composition on the Interfacial Oxidation and Nitridation Mechanisms of Graphene Sheet.

Graphene is one of the most promising thermal protection materials for high-speed aircraft due to its lightweight and excellent thermophysical properties. At high Mach numbers, the extremely high postshock temperature would dissociate the surrounding air into a mixture of atomic and molecular components in a highly thermochemical nonequilibrium state, which greatly affects the subsequent thermal chemical reactions of the graphene interface. Through establishing a reactive gas-solid interface model, the reactive molecular dynamics method is employed in this study to reveal the influences of the thermochemical nonequilibrium gas mixture on the thermal oxidation and nitridation mechanisms of graphene sheet. The results show that three distinctive stages can be recognized during bombardment of various nonequilibrium gas components toward the graphene sheet: (i) collision and surface adsorption stage, (ii) gas-solid heterogeneous reaction stage, and (iii) gas phase homogeneous reaction stage. The surface catalysis effect is found to be dominant during the first two stages, which can influence the following ablation behavior of graphene significantly at high-temperature conditions. Moreover, surface catalysis, oxidation, nitridation, and ablation mechanisms between nonequilibrium gas and graphene interface are revealed, which is of high relevance for future interfacial design and application of graphene as a thermal protection material.

Rotary Wind-driven Triboelectric Nanogenerator for Self-Powered Airflow Temperature Monitoring of Industrial Equipment.

Heat dissipation performance is crucial for the operational reliability of industrial equipment, which can be monitored by detecting the wind or airflow temperature of the radiator. The emergence of triboelectric nanogenerators (TENGs) provides new routes for wind energy harvesting and self-powered sensing. Herein, a rotary wind-driven triboelectric nanogenerator (RW-TENG) with soft-contact working mode is newly designed to achieve tunable contact areas by utilizing the reliable thermal response of NiTi shape memory alloy (SMA) to air/wind temperature. The RW-TENG can generate different triboelectric outputs under air stimulation with different speeds or temperatures, which is demonstrated as a power source for online monitoring sensors, self-powered wind speed sensing, and airflow temperature monitoring. Specifically, a self-powered sensor of wind speed is demonstrated with a sensitivity of 0.526 µA m-1 s between 2.2 and 19.6 m s-1, and a self-powered monitoring device of high airflow temperature, which show relatively short response time (109 s), strong anti-interference ability and outstanding long-term durability. This study introduces an innovative route for real-time detection of airflow temperature in wind-cooled industrial equipment, showing broad application prospects for information perception and intelligent sensing of the industrial IoTs.

Ultrasound in paediatric surgery: A meta-analysis review of its influence on postoperative wound healing and infection rates.

Ultrasound (US) has traditionally been recognised for its imaging capabilities, but its emerging role as a therapeutic modality in postoperative wound management, especially in paediatric care, has garnered significant attention. This meta-analysis aimed to evaluate the influence of US on postoperative wound healing and infection rates in paediatric patients. From an initial pool of 1236 articles, seven were deemed suitable for inclusion. Postoperative wound healing was assessed using the Redness, Edema, Ecchymosis, Discharge, and Approximation (REEDA) scale. Notably, there was a significant difference in wound healing patterns between the US-treated and control groups (I2 = 94%, standardized mean difference [SMD]: -4.60, 95% confidence intervals [CIs]: -6.32 to -2.88, p < 0.01), as illustrated in Figure 4. Additionally, a marked difference in wound infection rates was observed between the groups (I2 = 93%, SMD: -5.86, 95% CIs: -9.04 to -2.68, p < 0.01), as portrayed in Figure 5. The findings underscore the potential benefits of US in enhancing postoperative wound healing and reducing infection rates in paediatric surgical settings. However, the application of US should be judicious, considering the nuances of individual patient needs and clinical contexts.

Staminal hairs increase pollinator attraction and pollination accuracy in Tradescantia fluminensis (Commelinaceae).

Staminal hairs are the particular appendages of stamens, which may affect pollinator foraging behaviour and pollen transfer. However, experimental evidence of the functions of staminal hairs in pollination remains scarce. Here, we conducted staminal hair manipulation experiments in Tradescantia fluminensis (Commelinaceae) to investigate their effects on visitation and pollen transfer by bees. Our observations revealed that both visitation rates and visit duration of honeybees (Apis cerana) to control flowers were significantly higher than that of hairless flowers. Moreover, removing the staminal hairs significantly decreased pollen deposition by honeybees (A. cerana), but did not affect pollen removal. The staminal hair was similar in length to the stamen and the pistil of T. fluminensis. The staminal hairs provide more footholds for honeybees, and they lay prone on the staminal hairs to collect pollen, which increased the accuracy of pollination through the consistent pollen placement and pick-up on the ventral surface of honeybees. These results showed that the staminal hairs in T. fluminensis may represent an adaptation to attract pollinators and enhance pollination accuracy.

Identification of A Novel Variant of Filamin A Destroying the Attraction Between Benzene Rings and Sulfhydryl in Developmental Dysplasia of the Hip.

Developmental dysplasia of the hip (DDH), characterized by acetabular deformity that manifests from loose ligaments to complete dislocation of the hip, can cause notable pain and dysfunction and lead to hip dislocation, secondary fractures, scoliosis, and osteoarthritis of hip. Variants in FLNA may produce a spectrum of malformations in multiple organs, especially the skeleton. This study aimed to identify the genetic etiologies of DDH patients and provide genetic testing information for further diagnosis and treatment of DDH. We recruited a Chinese woman with DDH and her family members. Whole-exome sequencing was used to identify the patient's genetic etiologies. Protein models were used to analyze the pathogenic mechanism of the identified variants. A novel variant (c.3493T>G, p.C1165G) of FLNA was detected. The structural models of the mutant FLNA protein indicated that the variant would lose its sulfhydryl side chain and destroy the attraction between benzene rings and sulfhydryl. We reported a novel variant (c.3493T>G, p.C1165G) of FLNA in a Chinese woman with DDH. Our research outcome enriches the gene pool for hip dysplasia and emphasizes the pathogenicity of sulfhydryl side chain disruption in FLNA.

DFT study of SF6 adsorption by Pd-doped hydroxyl-terminal modified Ti3C2Tx MXene.

CONTEXT: SF6 gas has a strong greenhouse effect, and how to treat SF6 in an environmentally friendly way has been a hot topic of current research. In this paper, the adsorption behavior of SF6 on the surface of Pd-doped hydroxyl-terminated modified Ti3C2Tx (i.e., Ti3C2(OH)2) was investigated based on the density functional theory using two-dimensional MXene as the catalyst. The structures of different Pd-doped Ti3C2(OH)2 were analyzed and the most structurally stable doped structures were selected as the basis for subsequent calculations. A large number of adsorption configurations were constructed and geometrically optimized, and the adsorption energy, charge transfer, differential charge density, and density of states of the systems were calculated in order to analyze the gas-solid interactions and find the surface active sites; compared with the adsorption performance of undoped Ti3C2(OH)2 on SF6, it was found that Pd doping played a less inhibitory role in the adsorption of SF6 on the Ti3C2(OH)2 surface. The results of this study can provide theoretical support for the use of Pd-doped Ti3C2(OH)2 as a catalyst for the degradation of SF6. METHODS: In this paper, simulations of SF6 adsorption on Ti3C2Tx surfaces are based on density functional theory and are carried out in the Dmol3 module of Material Studio. To better describe the non-uniform electron density of the actual system, the PBE functional in the generalized gradient approximation (GGA) was chosen for the optimization of the structure of the gas-solid interface system and the calculation of the relevant electronic properties, combined with the Grimme dispersion correction in the DFT-D dispersion correction for the electron exchange correlation term. Because both Pd and Ti are transition metal elements, the mode-conserving pseudopotential DNP basis set containing relativistic effects was chosen for the electronic wave function expansion. In this paper, an all-electron model is used for the inner core treatment of gas molecules and a density generalized semi-nuclear pseudopotential DSSP is used for the solid surface treatment.

Density functional theory studies of Ti3C2TxMXene nanosheets decorated with Au for sensing SF6/N2nitrogen-containing decomposition gases.

SF6/N2mixture is an alternative gas of SF6, which is already used in electrical equipment. When a malfunction occurs , SF6/N2will decompose and further react with trace water and oxygen to produce nitrogen-containing gases such as NO, NO2, N2O and NF3. It is necessary to monitor these gases to ensure the safe operation of the equipment. This paper is based on density functional theory (DFT), the nanomaterial Ti3C2Txdoped with Au atom was selected as sensing material. The result shows that Au/Ti3C2Txhas larger adsorption energy when NO and NO2adsorbed on the surface, the stable structures were conformed more easily with NO and NO2compared with N2O and NF3. The density of states analysis and the frontier molecule orbital analysis reveal more change of the system before and after NO and NO2adsorption, suggesting the material showed good sensitivity performance to NO and NO2. Thus, Au/Ti3C2Txis considered to have the potential for sensing NO and NO2.

Single-shot image restoration via a model-enhanced network with unpaired supervision in an optical sparse aperture system.

We propose a model-enhanced network with unpaired single-shot data for solving the imaging blur problem of an optical sparse aperture (OSA) system. With only one degraded image captured from the system and one "arbitrarily" selected unpaired clear image, the cascaded neural network is iteratively trained for denoising and restoration. With the computational image degradation model enhancement, our method is able to improve contrast, restore blur, and suppress noise of degraded images in simulation and experiment. It can achieve better restoration performance with fewer priors than other algorithms. The easy selectivity of unpaired clear images and the non-strict requirement of a custom kernel make it suitable and applicable for single-shot image restoration of any OSA system.

Drying Kinetics of Microwave-Assisted Drying of Leaching Residues from Hydrometallurgy of Zinc.

In the hydrometallurgical process of zinc production, the residue from the leaching stage is an important intermediate product and is treated in a Waelz kiln to recover valuable metals. To ensure optimal results during the Waelz kiln process, it is necessary to pre-treat the residues by drying them first due to their higher water content. This work studies the residue's drying process using microwave technology. The study results indicate that microwave technology better removes the residue's oxygen functional groups and moisture. The dehydration process's effective diffusion coefficient increases as the microwave's heating power, the initial moisture content, and the initial mass increase. The Page model is appropriate for imitating the drying process, and the activation energy of the drying process for the residues is -13.11217 g/W. These results indicate that microwave technology efficiently dries the residues from the leaching stage. Furthermore, this study provides a theoretical basis and experimental data for the industrial application of microwave drying.

Development and usability of a Mobile Interactive Application (VCPW) for Vascular Crisis Prewarning after Skin Flap Transplantation.

Background: In microsurgical tissue transfer, skin flap transplantation is frequently used to heal the surface of a wound. Effective microcirculation surveillance of the skin flap is crucial. However, with traditional monitoring methods-that is, clinical observation-vascular crisis can still occur, thereby impairing postoperative recovery. A smartphone application is required to assist health care professionals in the standardized collection of flap perfusion parameters for flap management. Methods: The Vascular Crisis Prewarning Application was created using a design science research methodology that prioritizes users and problems. The system usability scale was used to assess the application's usability among medical practitioners. The application was used at the clinic from December 2020 to September 2022. The unplanned return to the operating room, time to diagnose vascular crisis, and flap survival rate were compared with and without the application. Results: The application consisted of 5 modules: patient addition and basic information entry, flap labeling, flap observation, crisis warning, and case archiving. The average rating for the application's usability among medical practitioners was 97.95 score (SD 2.36). With the application, the time to detect vascular crisis reduced from 26.71 to 16.26 h (P < 0.001), the unplanned return to the operation room increased from 8.18% to 10.24% (P = 0.587), and the flap survival rate went from 94.55% to 99.21% (P = 0.083). Conclusions: An easy-to-use flap perfusion monitoring and prewarning application for medical practitioners was produced using a user-centered development method. The application provided a more standardized and accurate platform for data collection in flap management and reduced the time to detect vascular crisis. Larger cohort studies are required in the future to better assess the full potential of the application.

Construction of response surface model for photoacoustic-based H2S measurement system and significance analysis of multiple influential factors.

Herein we first introduce the relationship between the photoacoustic (PA) signals' intensity of hydrogen sulfide (H2S) versus multiple parameters of optical path conditions, following by the construction of response surface method (RSM)-based models of the PA signals' intensity versus the distance l1 from the laser head to the convex lens, the distance l2 from the convex lens to the PA cell (PAC), and the distance l3 from the geometric center line of the light beam to the acoustic sensor. After that, we perform the significance analysis. The results show that the RSM model with a third-order configuration is relatively preferred. The distances l1, l2 and l3 all have significant influences on the PA signals' intensity. Additionally, we ameliorated the performance of the full third-order model by removing the non-significant terms.

Efficacy comparison of vascularized iliac crest bone flap and Ilizarov bone transport in the treatment of traumatic bone defects of the tibia combined with large soft tissue defects.

BACKGROUND: Traumatic tibial defect complicated with soft tissue defect is a difficult problem in clinic. Vascularized iliac crest bone flap (VIBF) and Ilizarov bone transport are effective methods to treat tibial defects with limited defect length, which most need to be explored accordingly. METHODS: In this study, a total of 68 patients with traumatic tibial defect (ranging from 4 to 10 cm) and large soft tissue defect were collected retrospectively. The soft tissue defects were repaired by latissimus dorsal musculocutaneous flap (LD), anterolateral thigh flap (ALTF) or both. Thirty-three cases were treated with vascularized iliac crest bone flap transplantation and 35 cases were treated with Ilizarov bone transport. Intraoperative and postoperative follow-up data (including operation time, blood loss, bone union time, external fixation time, external fixation index, complication rate, reoperation rate, and functional evaluation) were recorded, and comparative analysis was performed. RESULTS: The median follow-up time was 32 months. Compared with Ilizarov group, the VIBF group exhibited statistically faster bone union time (6.3 ± 1.0 vs. 18.2 ± 3.0 months). Moreover, the VIBF group showed shorter EFT (7.3 ± 1.0 vs. 19.2 ± 3.0 months) and a better EFI (34.8 ± 9.2 vs. 84.2 ± 23.7 days/cm). The excellent and good rate of lower limb appearance evaluation in VIBP group was significantly better than that in Ilizarov group. The complication rate and reoperation rate were significantly higher in Ilizarov group. CONCLUSION: In summary, compared with Ilizarov bone transport, VIBP has the advantages of faster healing, shorter external fixation time, lower complication and reoperation rate, and better appearance within the limited defect length. Ilizarov bone transport is still preferred when the defect length exceeds the maximum repair length of the iliac flap. The daily handling required by bone transport process is painful. LEVEL OF EVIDENCE: III, Case-control study.

Degradation Behaviors and Mechanism of Nitrile Butadiene Rubber Caused by Insulating Medium C5F10O.

C5F10O is a promising insulating medium in the manufacturing of environmentally friendly gas-insulated switchgears (GISs). The fact that it is not known whether it is compatible with sealing materials used in GISs limits its application. In this paper, the deterioration behaviors and mechanism of nitrile butadiene rubber (NBR) after prolonged exposure to C5F10O are studied. The influence of C5F10O/N2 mixture on the deterioration process of NBR is analyzed through a thermal accelerated ageing experiment. The interaction mechanism between C5F10O and NBR is considered based on microscopic detection and density functional theory. Subsequently, the effect of this interaction on the elasticity of NBR is calculated through molecular dynamics simulations. According to the results, the polymer chain of NBR can slowly react with C5F10O, leading to deterioration of its surface elasticity and loss of inside additives, mainly ZnO and CaCO3. This consequently reduces the compression modulus of NBR. The interaction is related to CF3 radicals formed by the primary decomposition of C5F10O. The molecular structure of NBR will be changed in the molecular dynamics simulations due to the addition reaction with CF3 on NBR's backbone or branched chains, resulting in changes in Lame constants and a decrease in elastic parameters.

Compatibility and Interaction Mechanism between the C4F7N/CO2/O2 Gas Mixture and FKM and NBR.

The C4F7N/CO2/O2 gas mixture received a great deal of attention for its potential use in eco-friendly gas-insulated equipment (GIE). The evaluation of the compatibility between C4F7N/CO2/O2 and sealing rubber is necessary and significant considering the high working pressure (0.14-0.6 MPa) of GIE. Herein, we explored the compatibility between C4F7N/CO2/O2 and fluororubber (FKM) and nitrile butadiene rubber (NBR) for the first time by analyzing the gas components, rubber morphology, elemental composition, and mechanical properties. The interaction mechanism of the gas-rubber interface was further investigated based on the density functional theory. We found that C4F7N/CO2/O2 is compatible with FKM and NBR at 85 °C, while the surface morphology changed at 100 °C, with white granular and agglomerated lumps appearing on FKM and multi-layer flakes being generated on NBR. The accumulation of the fluorine element occurred, and the compressive mechanical properties of NBR deteriorated after the gas-solid rubber interaction. Overall, the compatibility between FKM and C4F7N/CO2/O2 is superior, which could be employed as the sealing material for C4F7N-based GIE.

Pedicled iliac bone flap grafting in the treatment of late presentation Legg-Calvé-Perthes disease.

Background: Legg-Calvé-Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis affecting children. The lack of effective and timely treatment results in severe sequelae in children (especially older ones). Although LCPD has been widely studied, little is known about its etiology. As a result, its clinical management is still challenging. This study will investigate the clinical and radiological results of patients older than 6 years and treated with pedicled iliac bone flap grafting for LCPD. Materials and methods: A total of 13 patients (13 hips) with late presentation of LCPD were treated with pedicled iliac bone flap grafting. Of the 13 patients, 11 were male and 2 were female. The average age of the patients was 8.4 years (range 6-13). Preoperational radiographs and pain scores were analyzed for lateral pillar classification and the Oucher scale. The final follow-up radiograph was classified using a modified Stulberg classification. Limping, extremity length inequality, and range of motion were clinically assessed. Results: The average follow-up of the patients was 70 months (range 46-120). During the surgery, seven hips were found to be lateral pillar grade B, two were grade B/C, and four were grade C. In the final examination, 12 hips were evaluated as good (Stulberg class I or II) and one as medium (Stulberg class III). There was limb shortening in one patient who was Stulberg class III. There was a significant difference between the preoperational and postoperational radiographic values and the Ocher scale, regardless of the surgical staging (P < 0.05). Conclusions: Pedicled iliac bone flap graft can treat LCPD accompanied by pain and lateral pillar stage B, B/C, and C in children over 6 years. Level of Evidence: Level IV-case series.

Triboelectric Mechanism of Oil-Solid Interface Adopted for Self-Powered Insulating Oil Condition Monitoring.

The liquid-solid contact electrification mechanism has been explored in the aqueous solution system, but there are few systematic studies on oil-solid triboelectrification. Herein, an oil droplet triboelectric nanogenerator (Oil-droplet TENG) is designed as the probe to investigate the charge transfer properties at oil-solid interface. The charge transfer kinetics process is disclosed by the electrical signals produced, showing that the electron species initially predominated the oil-solid triboelectrification. The molecular structure and electronic properties of oil also affect triboelectric performance. Further, the charge transfer principle in multi-component liquid mixture during the electric double layer (EDL) development process is proposed to explain the component competition effect. As a proof of concept, a tubular-TENG is designed as a self-powered sensor for transformer oil trace water detection. The device demonstrates high water sensitivity with a detection limit of 10 µL L-1 and a response range of 10-100 µL L-1 . This work not only reveals the oil-solid triboelectric and charge transfer competition mechanism in EDL, but also open up a new channel for real-time online monitoring of trace water in transformer oil, which holds promise for information perception and intelligent operation of transformers in the power industry.

Analysis of Clinical Treatment of Laryngeal Stenosis After Radiotherapy and Supracricoid Partial Laryngectomy with Cricohyoidoepiglottopexy of Mid-stage and Advanced Laryngeal Cancer.

OBJECTIVE: To investigate the possible causes and treatment methods of laryngeal stenosis after radiotherapy following supracricoid partial laryngectomy with cricohyoidoepiglottopexy (SCPL-CHEP). METHODS: The data of seven patients with laryngeal stenosis after radiotherapy following SCPL-CHEP were analysed retrospectively. All patients were diagnosed with mid-stage or advanced laryngeal carcinoma before surgery, and the pathological type was squamous cell carcinoma. All patients met the requirements for SCPL-CHEP surgery. When laryngeal stenosis was found during the post-surgical follow-up period, patients were immediately given the appropriate treatment according to their conditions. RESULTS: All seven patients had laryngeal stenosis. One patient underwent granulation resection using a laryngoscope, four patients underwent granulation removal + low-temperature plasma ablation using a laryngoscope, and two patients underwent laryngeal dehiscence surgery + laryngotracheal T-tube placement. All patients recovered well after surgery, with patent airways. CONCLUSION: Laryngeal stenosis in patients with mid- and late-stage laryngeal carcinoma is one of the rare complications of SCPL-CHEP. Second-stage laryngeal dilatation can be selected according to the patient's laryngeal stenosis. Most patients with laryngeal stenosis can be extubated completely.

Fluorescent property of carbon dots extracted from cigarette smoke and the application in bio-imaging.

Cigarette smoke is one of the six major pollution sources in the room air. It contains large number of particles with size less than 10 nm. There exist carbon dots (CDs) in cigarette smoke which have strong fluorescence and with good bio-compatibility and low toxicity. CDs in cigarette smoke can be applied in bio-imaging which has great potential applications in the integration of cancer diagnosis and treatment. In this paper, CDs were extracted from cigarette smoke. Then, sodium borohydride was added to CDs aqueous solution for reduction and the reduced CDs (R-CDs) were used for biological cell imaging. The results indicate that the CDs with the particle size <10 nm in cigarette smoke are self-assembled by the polymerizated polycyclic aromatic hydrocarbons (PAHs) and ammonium nitrite which are disk nano-structure composed of sp2/sp3 carbon and oxygen/nitrogen groups or polymers. Sodium borohydride can reduce the carbonyl group on the surface of CDs to hydroxyl group and increase the ratio of the Na 1s ratio of the CDs from 1.86 to 7.42. The CDs can emit blue fluorescence under ultraviolet irradiation. After reduction, the R-CDS have the intensity of fluorescence 7.2 times than before and the fluorescence quantum yield increase from 6.13% to 8.86%. The photoluminescence (PL) wavelength of R-CDS have red-shift of 7 nm which was due to the increasing of Na element ratio. The onion epidermal cells labeled with R-CDs show that the CDs could pass through the cell wall into the cell and reach the nucleus. The cell wall and the nucleus could be clearly visualized. CDs also shows low toxicity to human bronchial epithelial cells (BEAS-2B) with good biological activity. The obtained results indicate that the CDs and R-CDs have good fluorescent property which could be used as bio-imaging agent.