聚合物半导体光催化合成过氧化氢:光氧化还原中心的空间分离和协同利用

以地表丰富的水和/或氧气为原料,以太阳能为能量来源的光催化合成过氧化氢是面向碳中和的一个颇具吸引力的路径。近年来,以能带、活性位点、组成等可调的聚合物半导体为光催化剂,开展光合成过氧化氢的研究进入了新的高峰期。当前,该研究主要面临两大关键挑战:1)由于材料性质固有的限制,光氧化还原中心通常难以分离,导致光生电荷复合严重,使得光催化合成过氧化氢的活性较差;2)氧化还原中心的利用率低,多数情况下,只有氧化端或还原端参与过氧化氢的合成,另一侧则与牺牲剂反应消耗。对此,本文聚焦光氧化还原中心的空间分离和协同利用来阐述聚合物半导体光催化合成过氧化氢的最新进展。光氧化还原中心空间分离的关键是在聚合物中设计电子给体和供体单元,例如在聚合物框架中引入原子级金属,构建金属-有机给吸电子体系,或构建全有机给吸电子体系。根据氧化还原中心的光催化行为,协同利用主要分为以下三种模型:1)氧还原耦合有机分子氧化;2)水氧化耦合有机分子还原,3)氧还原耦合水氧化。在此基础上,本文详细探讨了针对上述两个关键挑战的调控模式、特性、催化机制和反应途径。最后,我们阐述了光催化合成过氧化氢的潜在应用,并展望了光催化合成过氧化氢中理性设计氧化还原中心协同利用模式的机遇和挑战。

[Co_(3)]簇基金属有机框架材料实现“一石二鸟”高效催化CO_(2)转化为噁唑烷酮

噁唑烷酮是药物化学中重要的中间体,可以通过炔丙基胺类或氮杂环类化合物与CO_(2)的环化获得。合成一种可以同时催化这两种反应的催化剂是一件有很强吸引力,但极具挑战性的工作。本文合成了一例独特的三维(3D)[CO_(3)]簇金属-有机框架(MOF){(CH_(3)NH_(2)CH_(3))2[CO_(3)(BCP)_(2)]·6H_(2)O·4DMF}n(1)并进行了表征,1表现出良好的溶剂稳定性和热稳定性。催化实验结果表明,1可以高效催化氮杂环或炔丙基胺类化合物与CO_(2)反应来制备噁唑烷酮,并且催化剂对两种反应都具有广泛的底物普适性和良好的循环使用性。对照实验和核磁共振测试表明,1中路易斯酸和路易斯碱位点的共存是高效催化的原因。化合物1作为一种新型催化剂,成功实现了“一石二鸟”高效催化CO_(2)转化为噁唑烷酮。

Elastic-viscoplastic constitutive equations of K439B superalloy and thermal stress simulation during casting process

K439B nickel-based superalloy is a new type of high-temperature material.There is insufficient research on its constitutive equations and numerical modeling of thermal stress.Isothermal tensile experiments of K439B superalloy at different temperatures(20°C-1,000°C)and strain rates(1.33×10^(-3)s^(-1)-5.33×10^(-3)s^(-1))were performed by using a Gleeble-3800 simulator.The elastic moduli at different temperatures(20°C-650°C)were measured by resonance method.Subsequently,stress-strain curves were measured for K439B superalloy under different conditions.The elastic-viscoplastic constitutive equations were established and the correspongding parameters were solved by employing the Perzyna model.The verification results indicate that the calculated values of the constitutive equations are in good agreement with the experimental values.On this basis,the influence of process parameters on thermal stress was investigated by numerical simulation and orthogonal experimental design.The results of orthogonal experimental design reveal that the cooling mode of casting has a significant influence on the thermal stress,while pouring temperature and preheating temperature of shell mold have minimal impact.The distribution of physical fields under optimal process parameters,determined based on the orthogonal experimental design results,was simulated.The simulation results determine separately the specific positions with maximum values for effective stress,plastic strain,and displacement within the casting.The maximum stress is about 1,000.0 MPa,the plastic strain is about 0.135,and the displacement is about 1.47 mm.Moreover,the distribution states of thermal stress,strain,and displacement are closely related to the distribution of the temperature gradient and cooling rate in the casting.The research would provide a theoretical reference for exploring the stress-strain behavior and numerical modeling of the effective stress of the alloy during the casting process.

Assessment of quality of life for the patients with cervical cancer at different clinical stages

With improved overall survival of cervical cancer patients, the importance of the quality of life (QOL) is increasingly recognized. This study was conducted to compare the QOL of women with different stage cervical cancer before and after treatment to facilitate improved cervical cancer prevention and treatment. We used the generic Medical Outcomes Study Short Form-36 (MOS SF-36) to collect QOL information. Based on SF-36, we interviewed cervical cancer patients at West China Second Affiliated Hospital and Sichuan Cancer Hospital between May 2010 and January 2011. A total of 92 patients with precancerous lesions, 93 with early cancer, and 35 with advanced cancer responded to our survey. Average physical component summary (PCS) scores were significantly different between the three groups at every time point (P < 0.05). Average mental component summary (MCS) scores were significantly different between the three groups after treatment (P < 0.05). Average PCS and MCS scores increased gradually from the pretreatment to posttreatment period for patients with precancerous lesions. However, they reached the lowest at 1 month after treatment for patients with early and advanced cancers and rebounded between 1 and 6 months after treatment. Our results indicate that patients with precancerous lesions and early cervical cancer show better overall QOL than do those with advanced cervical cancer. Additionally, patients with early cancer recover more quickly than do those with advanced cancer in terms of both physical and mental functions. Thus, early detection and treatment initiatives may improve the QOL for patients with precancerous lesions and cervical cancer.

Hepatitis B surface antigen clearance in inactive hepatitis B surface antigen carriers treated with peginterferon alfa-2a

AIM: To examine the association between interferon(IFN) therapy and loss of hepatitis B surface antigen(HBs Ag) in inactive HBs Ag carriers. METHODS: This was a retrospective cohort study in inactive HBs Ag carriers, who were treatment-naive, with a serum HBs Ag level < 100 IU/m L and an undetectable hepatitis B virus(HBV) DNA level(< 100 IU/m L). All the 20 treated patients received subcutaneous PEG-IFN alfa-2a 180 μg/wk for 72 wk and were then followed for 24 wk. There were 40 untreated controls matched with 96 wk of observation. Serum HBs Ag, HBV DNA, and alanine aminotransferases were monitored every 3 mo in the treatment group and every 3-6 mo in the control group. RESULTS: Thirteen(65.0%) of 20 treated patients achieved HBs Ag loss, 12 of whom achieved HBs Ag seroconversion. Mean HBs Ag level in treated patients decreased to 6.69 ± 13.04 IU/m L after 24 wk of treatment from a baseline level of 26.22 ± 33.00 IU/m L. Serum HBV DNA level remained undetectable(< 100 IU/m L) in all treated patients during the study. HBs Ag level of the control group decreased from 25.72 ± 25.58 IU/m L at baseline to 17.11 ± 21.62 IU/m L at week 96(P = 0.108). In the control group, no patient experienced HBs Ag loss/seroconversion, and two(5.0%) developed HBV reactivation.CONCLUSION: IFN treatment results in HBs Ag loss and seroconversion in a considerable proportion of inactive HBs Ag carriers with low HBs Ag concentrations.

Quality of life in women with cervical precursor lesions and cancer:a prospective, 6-month, hospital-based study in China

The overall survival of patients with cervical cancer has improved due to detection at an early stage and availability of comprehensive treatments in China. As patients' lives prolonged, it is important to understand their health-related quality of life(QoL) during and after treatment. We used the EQ-5D questionnaire to assess QoL of 194 patients with cervical lesions at Sichuan University West China Second Hospital between May 2010 and January 2011. Patients were surveyed before primary treatment and at 1, 3, and 6 months after primary treatment. Results showed a consistent decline in EQ-5D scores in the spectrum of cervical lesions at each time point after treatment(all P < 0.05). For patients with precursor lesions, there was an increasing trend along the timeline of treatment(P < 0.01). For patients with early-stage cervical cancer, EQ-5D scores declined in the first month(P = 0.01) and gradually increased to higher levels at 6 months post-treatment than those before treatment(P < 0.01). EQ-5D scores followed a similar trend in patients with advanced cervical cancer(P = 0.04), though they did not statistically rebound after 6 months(0.84 ± 0.19 vs. 0.86 ± 0.11, P = 0.62). Regarding advanced cervical cancer, EQ-5D scores for women above 40 years of age appeared to recover more rapidly and reached higher levels than those for women below 40 years(P = 0.03). Caution and extra care are recommended in the early period of cervical cancer treatment given the slight deterioration in the QoL, and in particular, for younger cervical cancer patients. Our study implies that health care providers may need to improve the health-related QoL of cervical cancer patients.

单一相板钛矿TiO2的制备及光催化性能研究

以四氯化钛(TiCl4)、尿素、乳酸钠为反应物,采用水热法制备了单一相板钛矿TiO2。利用X射线衍射仪、拉曼光谱仪、扫描电镜、透射电镜、比表面积分析仪等手段对所得样品进行了结构和形貌分析。以亚甲基蓝溶液为目标降解物,在紫外灯照射下测试了所得样品的光催化活性。实验结果表明,所得样品为长约60~80 nm、宽约20~30 nm的板钛矿TiO2纳米片。在紫外灯照射40 min后,所得单一相板钛矿TiO2对亚甲基蓝溶液的脱色率为94.5%,明显高于相应的商业级TiO2 (P25) (86.7%)。

HBV DNA level and antigen concentration in evaluating liver damage of patients with chronic hepatitis B

OBJECTIVE: To investigate the correlations between HBV DNA levels and viral antigen concentrations in patients with chronic hepatitis B and their significance in clinical practice. METHODS: The HBV DNA levels and serological markers of 118 patients with chronic hepatitis B and 87 patients with liver cirrhosis who had not been treated with antiviral drugs were determined as well as the other parameters relevant to liver function. RESULTS: The HBV DNA levels of the patients with chronic hepatitis anti cirrhosis were expressed as geometric mean±SD, 3.83×10~6±1.34 copies/ml anti 6.98×10~5±1.29 copies/ml, and their HBeAg concentrations expressed as the luminescent values rate of sample to control (s/co) were 35.40±1.26 and 4.05±1.28, respectively. The HBV DNA levels in HBeAg positive group were significantly higher than those in HBeAg negative group (P<0.0001). The correlation coefficient between HBV DNA level and HBeAg or HBsAg concentration was only O. 273 anti -0.12. During the recovery of hepatic function, the reduction of ALT or AST in patients with high viral content was significantly lower than that in patients with low viral content. No correlation was observed between HBV DNA and ALT levels. CONCLUSION: There are significant correlations between HBV DNA level anti HBeAg concentration, but the coefficient is lower. HBV DNA level is not significantly related to ALT, but it could affect the recovery of liver function.

Peginterferon alfa-2a for the treatment of chronic hepatitis C in the era of direct-acting antivirals

BACKGROUND: The availability of novel direct-acting antivirals (DAAs) represents a new era of curative hepatitis C virus (HCV) treatment, with over 95% of patients infected with HCV genotype 1 achieving sustained virological response (SVR). Nevertheless, the majority of patients globally are unable to access these treatments because of cost and infrastructure constraints and, thus, remain untreated and uncured. DATA SOURCE: Relevant articles of peginterferon (PegIFN)-based treatments in HCV and sofosbuvir-based treatments, simeprevir, daclatasvir/asunaprevir, ritonavir-boosted paritaprevir/ombitasvir/dasabuvir, and grazoprevir/elbasvir, were searched in PubMed database, including general population and special population. RESULTS: PegIFN in combination with ribavirin remains an important and relevant option for some patients, achieving SVR rates of up to 79% in genotype 1 and 89% in genotype 2 or 3 infections, which increases for patients with favorable IL28B genotypes. Triple therapy of DAA plus PegIFN/ribavirin is effective in treating difficult-to-cure patients infected with HCV genotype 3 or with resistance-associated variants. Owing to its long history in HCV management, the efficacy, tolerability and long-term outcomes associated with PegIFN alfa-2a are well established and have been validated in large-scale studies and in clinical practice for many populations. Furthermore, emerging data show that IFN-induced SVR is associated with lower incidences of hepatocellular carcinoma compared with DAAs. On the contrary, novel DAAs have yet to be studied in special populations, and long-term outcomes, particularly tumor development and recurrence in patients with cirrhosis and/or hepatocellular carcinoma, and reactivation of HBV in dually infected patients, are still unclear. CONCLUSION: In this interferon-free era, PegIFN-based regimens remain a safe and effective option for selected HCV patients.

Progress of Microfluidics for Biology and Medicine

Microfluidics has been considered as a potential technology to miniaturize the conventional equipments and technologies. It offers advantages in terms of small volume, low cost, short reaction time and highthroughput. The applications in biology and medicine research and related areas are almost the most extensive and profound. With the appropriate scale that matches the scales of cells, microfluidics is well positioned to contribute significantly to cell biology. Cell culture, fusion and apoptosis were successfully performed in microfluidics. Microfluidics provides unique opportunities for rare circulating tumor cells isolation and detection from the blood of patients, which furthers the discovery of cancer stem cell biomarkers and expands the understanding of the biology of metastasis. Nucleic acid amplification in microfluidics has extended to single-molecule, high-throughput and integration treatment in one chip. DNA computer which is based on the computational model of DNA biochemical reaction will come into practice from concept in the future. In addition, microfluidics offers a versatile platform for protein-protein interactions, protein crystallization and high-throughput screening. Although microfluidics is still in its infancy, its great potential has already been demonstrated and will provide novel solutions to the high-throughput applications.

Phase Ⅱb trial of in vivo electroporation mediated dualplasmid hepatitis B virus DNA vaccine in chronic hepatitis B patients under lamivudine therapy

AIM To assess the efficacy and safety of in vivo electroporation(EP)-mediated dual-plasmid hepatitis B virus(HBV) DNA vaccine vs placebo for sequential combination therapy with lamivudine(LAM) in patients with chronic hepatitis B. METHODS Two hundred and twenty-five patients were randomized to receive either LAM + vaccine(vaccine group, n = 109) or LAM + placebo(control group, n = 116). LAM treatment lasted 72 wk. Patients received the DNA vaccine or placebo by intramuscular injection mediated by EP at weeks 12(start of treatment with vaccine or placebo, SOT), 16, 24, and 36(end of treatment with vaccine or placebo, EOT). RESULTS In the modified intent-to-treat population, morepatients had a decrease in HBV DNA > 2 log10 IU/m L in the vaccine group at week 12 after EOT compared with the control group. A trend toward a difference in the number of patients with undetectable HBV DNA at week 28 after EOT was obtained. Adverse events were similar. In the dynamic per-protocol set, which excluded adefovir(ADV) add-on cases at each time point instantly after ADV administration due to LAM antiviral failure, more patients had a decrease in HBV DNA > 2 log10 IU/mL in the vaccine group at week 12 and 28 after EOT compared with the control group. More patients with undetectable HBV DNA at week 28 after EOT in the vaccine group were also observed. Among patients with a viral load < 1000 copies/mL at week 12, more patients achieved HBeA g seroconversion in the vaccine group than among controls at week 36 after EOT, as well as less virological breakthrough and YMDD mutations. CONCLUSION The primary endpoint was not achieved using the HBV DNA vaccine. The HBV DNA vaccine could only be beneficial in subjects that have achieved initial virological response under LAM chemotherapy.

Quasi-Spherical Brookite TiO_2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate(Ti(OC_4H_9)_4,TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods,such as X-ray diff raction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer–Emmett–Teller(BET) measurements and ultraviolet–visible diff use spectroscopy(UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO_2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO_2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity,and the corresponding degradation rate of methylene blue(10 mg/L) reached 96.7% after 90 min of illumination. In addition,the formation mechanism of pure-phase brookite TiO_2 was investigated. It was found that the formation of pure-phase brookite TiO_2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.

The Predictive Value of On-treatment Virological Response for Sustained Virological Response in Patients with Chronic Hepatitis C Receiving a Personalized Treatment Program

To investigate the effects of individualised treatment with peginterferon alpha-2a(40 kD)plus ribavirin in Chinese patients with CHC.Methods Total of 297 consecutive Chinese patients were enrolled,including 250 nave cases and 47 cases who were previously treated.Treatment duration was determined according to viral genotypes,prior treatment history and viral responses at week 4,12 and 24.Results Totally,235 patients(79.1%)completed treatment and 186(87.3%)achieved SVR.And 219 out of 289(75.8%)patients achieved HCV RNA negative at week 4(RVR)and 259 of 276(93.8%)at week 12.Among the 164 patients with RVR who completed follow-up,158(96.3%)achieved SVR.Patients with RVR had lower baseline viral loads than patients without RVR(P=0.034).The positive predictive value(PPV)of RVR for SVR was 90.7%(OR 2.10 vs.non-RVR,95%CI:0.50-8.7).Similar outcomes were observed among patients with HCV undetectable at week 12.Conclusions Viral suppression by week 4 is associated with a high rate of treatment success in treatment nave and experienced patients receiving individualized CHC therapy.

Early Evolution of Hepatitis B Virus Quasispecies During IFN-α Treatment

Objective To investigate the dynamic change of hepatitis B virus quasispecies within complete genome during the early stage of IFN-α treatment and its impact on virological response.Methods Sixteen patients with chronic hepatitis B receiving IFN-α treatment were investigated. HBV DNA was extracted from serum sample at baseline and week 12. The complete genome of HBV was amplified, then cloned and sequenced. The quasispecies heterogeneity of HBV complete genome was depicted at baseline and week 12. Results The quasispecies heterogeneity of the genome except for C-ORF were comparable in three groups at baseline and week 12. The quasispecies diversity at amino acid levels of responders within C-ORF were higher than that of non-responders at baseline. The quasispecies diversity within the C-ORF of partial responders was reduced in the early stage of IFN-α treatment. Furthermore, the mean genetic distance at amino acid levels of partial responders was significantly higher than that of the non-responders at week 12. The evolutionary rate was not different between non-responders and partial responders. Conclusions In the immune clearance phase, the patients who had greater viral quasispecies diversity within C-ORF at amino acid level had more chance to obtain the early virological response during IFN-α treatment.

Efficient CO_(2) electroreduction coupled with semi-dehydrogenation of tetrahydroisoquinoline by MOFs modified electrodes

Electroreduction of CO_(2) into formate catalyzed by metal-organic frameworks(MOFs) is a promising avenue to promote the carbon cycle,but the oxygen evolution reaction(OER) process in anode usually limited the reaction efficiency.Here,a new framework {(Me_(2) NH_(2))[Bi(L)]·4 DMF·2 H_(2) O}_n(V12) was constructed and structurally characterized(L=5,5'-(1,3,6,8-tetraoxo-1,3,6,8-tetrahydrobenzo [lmn][3,8]phenanthroline-2,7-diyl) dibenzene-1,3-dicarboxylic acid;DMF=N,N-dimethylformamide).V12 possesses large one-dimensional channels with the size of 1.5 × 0.7 nm and exhibits good stability in common solvents.After V12 was modified on electrode via electrodeposition,as-synthesized sample exhibits impressive catalytic performance for the transformation of CO_(2) into formate with Faraday efficiency of93.2% and current density of 11.78 mA cm^(-2) at-0.9 V(vs.RHE).Control experiments revealed that the MOFs electrodeposition strategy significantly improves the charge transfer rate and introduces more structural defects,which promotes the reaction activity.Moreover,tetra hydroisoquinoline is added as an accelerant in the anode to achieve the simultaneous generation of formate and dihydroisoquinoline.More importantly,the cell voltage is reduced from 2.79 to 2.52 V at 10 mA cm^(-2) in a two-electrode system due to more positive reaction kinetics.This work provides an enlightening strategy for using MOFs to establish an effective system to achieve CO_(2) reduction while obtaining high value-added oxidation products.

Effects of Ag,Co,and Ge additions on microstructure and mechanical properties of Be-Al alloy fabricated by investment casting

The effects of Ag,Co,and Ge additions on microstructure and mechanical properties of Be-35Al(wt.%)alloys fabricated by investment casting were studied.The results reveal that the trace metals 1.5wt.%Ag,0.7wt.%Co,and 0.8wt.%Ge additions do not change the nucleation temperature of Be phase.However,the nucleation temperature of the Al phase decreases from 642℃ to 630℃ by DSC due to the Ge addition.The strength of the alloys sharply increases due to the dissolution of the Ag and Ge solutes into the Al phase and the Co into the Be phase characterized by SEM and EDS.Obviously,the strength of Be-Al-Ag-Co-Ge alloy is improved by the solution strengthening.Furthermore,a few Ag_(3) Al particles contribute to the strength of the Al phase.Be-Fe-Al ternary intermetallic compounds which can effectively reduce the negative effect of an impurity element Fe on the mechanical properties of Be-Al alloys are also found by XRD and EDS.

Chinese Consensus on Diagnosis and Treatment of Hepatic Encephalopathy

Hepatic encephalopathy(HE)is a complex,neuropsychiatric abnormality that occurs as a consequence of metabolic disorders in patients with hepatic insufficiency.The pathogenesis is complex with a strong prognosticator of death.To standardize the clinical management of HE,relevant new data were reviewed and assessed by Chinese Committee of Experts on Hepatic Encephalopathy in China and was discussed and debated extensively.Then the consensus on the management of HE was developed.The final recommendations are based on the data available at the time of production of the document and may be updated with pertinent scientific developments at a later time.All the discussion was organized by the editorial board of Chinese Journal of Experimental and Clinical Infectious Diseases(Electronic Edition),Chinese Journal of Liver Diseases(Electronic Edition)and Infection International(Electronic Edition).The evidence gradings in the consensus are listed in Table1.

Signaling Pathways Associated with Cancer Stem Cells Play a Significant Role in Immunotherapy Resistance

Cancer stem cells(CSCs)are a subpopulation of tumor cells with properties of self-renewal,pluripotency,plasticity,and differentiation,and are associated with various aberrantly stimulated signaling pathways.They are responsible for tumor recurrence,distant metastasis,and drug resistance,thus inducing poor prognosis.Immunotherapy has achieved encouraging results.However,the resistance associated with its clinical application is a persistent problem in clinical and scientific researches.Increasing evidence shows that signaling pathways associated with CSCs mediate immunotherapy resistance.This review highlights the link between them,and focuses on the underlying mechanism so as to provide potential strategies and approaches for the development of new targets against the immune resistance challenge.

新型分离纯化技术在天然产物中的应用

天然产物是自然界生物在长久进化过程中经自然选择所保留下来的次生代谢物,因其丰富的药用价值而被广泛应用于多个领域,随着现代科学的发展,对于天然产物高纯度产品的需求也在不断增加。传统的分离方法通常存在有机溶剂消耗大、分离效果差、成本高、周期长等缺点,严重制约了天然产物在各领域的发展使用。新型分离纯化技术的出现为天然产物的提取、分离和应用提供了新的思路。本文在总结现有文献的基础上,对天然产物的新型分离纯化方法进行了综述,最后对天然产物分离纯化的研究瓶颈和未来发展方向进行了总结与讨论。

Exploring luminescence quenching on lanthanide-doped nanoparticles through changing the spatial distribution of sensitizer and activator

Luminescence quench is common in overdoped upconversion nanoparticles.Various methods have been proposed to counteract the adverse effects of concentration quenching on luminescence,but in upconversion nanoparticles that are highly doped with both sensitizers and activators,the factors that contribute to the diminishing of the emission cannot be summarized by a single cause.Herein,a core-shell design is used to spatially separate the sensitizer(Yb^(3+))and activator(Er^(3+))and to modulate the emission by changes in the distribution position as well as the concentration of the dopant ions in order to probe the factors affecting the luminescence.When the sensitizer ions are located in the core,the luminescence intensity of the nanoparticles is significantly weaker than that of the other distribution,which implies that the effect of sensitizer and activator on luminescence in the highly doped state has a different and more complex mechanism.The intensity of the emission is more affected by Yb^(3+)than Er^(3+),which includes not only the self-quenching of Yb^(3+),but also the dominance in the Yb^(3+)-Er^(3+)cross-relaxation.In this finding may provide new ideas for revealing the reasons for the diminished luminescence of highly doped upconversion nanoparticles and thus for enhancing luminescence.