Objective: To investigate the clinicopathological features, survival and prognostic factors for gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs) in a Chinese population.Methods: We investigated 154 consecutiv...Objective: To investigate the clinicopathological features, survival and prognostic factors for gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs) in a Chinese population.Methods: We investigated 154 consecutive patients(88 males, 66 females; median age 56 years, age range 9-86 years) diagnosed with GEP-NENs between 2001 and 2013 at The Affiliated Hospital of Qingdao University. Demographic, clinical and pathological variables and survival data were retrieved.Results: The pancreas was the most common site of involvement(63/154, 40.9%). Tumor size varied from 0.3 to 16.0 cm(median, 1.2 cm). The patients were followed up for a median period of 22 months(range, 1-157 months). The estimated 3- and 5-year overall survival(OS) rates for all patients were 84.0% and 81.9%, respectively. Multivariate analysis showed that larger tumor size, lymphatic metastases and distant metastases were significant predictors for poor survival outcome.Conclusions: Our data provide further information on the clinicopathological features of GEP-NENs in China. Additionally, we identified tumor size, lymphatic metastases and distant metastases as independent prognostic factors for long-term survival.展开更多
Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we o...Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.Methods:Thirty-six Sprague-Dawley rats weighing 150-180 g were randomly divided into six groups(n=6 in each group)including a normal control(NC)group,4 white LED groups at different light intensities(4,000,6,000,7,000,and 10,000 lux),and an ultraviolet B(UVB)lighting group(302 nm,1,000μw/cm2).After 24 hours of continuous illumination,full-field flash electroretinogram(FERG)and pathological examination were performed in each group.Results:As revealed by FERG,the impairment of retinal function gradually worsened with the increase of LED light intensity.In contrast,the UVB group had the most severe retinal function impairment.Particularly,the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group.In the NC group,the retina had typical morphologies featured by well-defined structures,clearly visible border between the inner and outer segments,and neatly arranged inner and outer nuclear layer cells.After 24 hours of illumination,the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged,along with a clear border;however,the inner and outer nuclear layers were randomly arranged,and some irregular nuclei and cells were lost.The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group,7,000 lux group,and 10,000 lux group.The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.Conclusions:Continuous exposure to white LED light can cause structural and functional damage to rat retinas,and such damage is related to the intensity of illumination.Therefore,the risk of retinal damage should be considered during LED illumination,and proper LED illumination intensity may help to maintain eye health.展开更多
Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 16...Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 160-180 g were randomly divided into four groups including a normal control group(NC group,n=12),an untreated alkali-burned model control group(MC group,n=15),a blank eye drop treatment group(BT group,n=15),and an SRL eye drop treatment group(ST group,n=15).Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3,7,and 14 days after alkali exposure.Three rats were randomly sacrificed in each group before modeling and 3,7,14 days after modeling,and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.Results:Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC,BT,and ST groups 1 day after alkali exposure but were alleviated at day 3.The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7(F=9.77,P<0.05)and 14(F=5.81,P<0.05).At day 1,the corneal limbal vascular network was markedly filled.SNV was obvious at days 3,7,and 14.The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups,and the CNV scores showed significant differences among these groups(day 3:F=8.60,P<0.05;day 7:F=11.40,P<0.05;and day 14:F=41.59,P<0.01).Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups(F=0.52,P>0.05;F=0.98,P>0.05).The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3,7,and 14 days after alkali exposure,and there were significant differences in relative gray-scale values among these groups(day 3:F=32.16,P<0.01;day 7:F=85.96,P<0.01;day 14:F=57.68,P<0.01).The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3,7,and 14,and there were significant differences in relative gray-scale values among groups(day 3:F=32.16,P<0.01;day 7:F=53.02,P<0.01;day 14:F=38.67,P<0.01).Conclusions:SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models.It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue,which may contribute to the inhibition of alkali-burn-induced CNV.展开更多
Objective: The aim of the study was to analyze the clinicopathologic characteristics of gastroenteropancreatic neuroendocrine neoplasm(GEP-NEN) and to explore the prognostic factors for patients and differences of imm...Objective: The aim of the study was to analyze the clinicopathologic characteristics of gastroenteropancreatic neuroendocrine neoplasm(GEP-NEN) and to explore the prognostic factors for patients and differences of immunohistochemical markers between neuroendocrine tumor(NET) and neuroendocrine carcinoma(NEC). Methods: Retrospective reviews were conducted for the charts of 119 patients with GEP-NEN at the Affiliated Hospital of Qingdao University(China) from August 2003 to December 2013. Kaplan-Meier method was used to do the overall survivals analysis for the patients at different levels of predictive factors. Meanwhile, Cox proportional hazard model was used to select independent risk factors of survival. Analysis of variance was used to compare the expression of immunohistochemical markers among different pathological grades. Results: Among 119 patients, pancreas(45/119, 37.82%) and rectum(33/119, 27.73%) were mostly involved. The onset age of GEP-NEN in female group was younger than that of the male group. There were 13 deaths(10.92%) during 18.9(0.1–133.4) months follow-up period. Multivariate analysis indicated that neural invasion, gender and pathological grades of NET and NEC were independent risk factors. In neuroendocrine neoplasm(NEN), Syn expression in G2 was higher than G1 and G3, while Cg A showed no significant difference. All markers showed no significant differences between NET and NEC. Conclusion: GEP-NEN may occur at multiple sites of digestive system and lack specific clinical manifestations. Syn expression detected for the prognosis of G1, G2 and G3 tumors have clinical significance. Neural invasion, sex and pathological grades were independent prognostic factors for GEP-NEN patients. No significant difference was found in different pathological grades of NET and NEC.展开更多
Objective: The aim of this study was to investigate the expressions of CD147 and CK19 in hepatocellular car- cinoma (HCC) and their clinical significance. Methods: The expressions of CD147 and CK19 were determined by ...Objective: The aim of this study was to investigate the expressions of CD147 and CK19 in hepatocellular car- cinoma (HCC) and their clinical significance. Methods: The expressions of CD147 and CK19 were determined by tissue microarray and immunohistochemistry (IHC) in 272 cases of HCC and 81 cases of adjacent tumorous tissue. Results: The positive expression of CD147 in HCC and adjacent tumorous tissue was 73.53% (200/272) and 13.58% (11/81) with signifi- cant difference (P < 0.05). The positive expression of CK19 in HCC and adjacent tumorous tissue was 14.34% (39/272) and 0 (0/81) with significant difference (P < 0.05). The positive expression of CD147 were closely correlated to the histological grade, clinical stage, tumor-free survival, diameter of tumor and embolus of cancer in aqueduct or portal vein; but not to the patients' sex, age, liver cirrhosis, AFP level, infection of HBV, lymph node metastasis, number of tumor, invasion liver involucrum and the micro-satellites (P > 0.05). The expression of CK19 in HCC were closely correlate to the tumor-free survival, histological grade, diameter of tumor, liver cirrhosis, micro-satellites, lymph node metastasis and clinical stage; but not to patients' sex, age, number of tumor, invasion liver involucrum, AFP level, infection of HBV and embolus of cancer in aqueduct or portal vein (P > 0.05). Among the patients of positive expression of CD147, the median replacing time and overall survival were 13 and 24 months, lower than 48 and 60 months in the patients of negative expression (P < 0.05). Among the patients of positive expression of CK19, the median replacing time and overall survival were 7 and 13 months, lower than 31 and 42 months in the patients of negative expression (P < 0.05). The expression of CD147 had no correlation with the expression of CK19 (r = 0.061, P = 0.317). Conclusion: The positive of CD147 and CK19 closely correlate with the clinical prognosis of HCC, it may indicate poor prognosis of HCC.展开更多
A novel grooving method for eliminating the bending-induced collapse of hexagonal honeycombs has been proposed,which lies in determining the appropriate grooving parameters,including the grooving spacing,angle,and dep...A novel grooving method for eliminating the bending-induced collapse of hexagonal honeycombs has been proposed,which lies in determining the appropriate grooving parameters,including the grooving spacing,angle,and depth.To this end,a framework built upon the experiment-based,machine learning approach for grooving parameters prediction was presented.The continuously grooved honeycomb bending experiments with various radii,honeycomb types,and thicknesses were carried out,and then the deformation level of honeycombs at different grooving spacing was quantitatively evaluated.A criterion for determining the grooving spacing was proposed by setting an appropriate tolerance for the out-of-plane compression strength.It was found that as the curvature increases,the grooving spacing increases due to the deformation level of honeycombs being more severe at a smaller bending radius.Besides,the grooving spacing drops as the honeycomb thickness increases,and the cell size has a positive effect on the grooving spacing,while the relative density has a negative effect on the grooving spacing.Furthermore,the data-driven Gaussian Process(GP)was trained from the collected data to predict the grooving spacing efficiently.The grooving angle and depth were calculated using the geometrical relationship of honeycombs before and after bending.Finally,the grooving parameters design and verification of a honeycomb sandwich fairing part were conducted based on the proposed grooving method.展开更多
Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 veg...Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 vegetable fields in administrative regions of China' Mainland, of which 122 were selected for further investigation. DOM properties were characterized by three-dimensional excitation-emission matrix(3D-EEM) fuorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry(FTICRMS)(field intensity is 15 Tesla). Our results indicated that the main constituents were UVA humic-like substances, humic-like substances, fulvic acid-like substances, and tyrosine-like substances. A total of 10,989 molecular formulae with a mass range of 100.04 to 799.59 Da were detected, covering the mass spectrometric information of the soil samples from 27 different regions. CHO and CHON molecules were dominant in DOM, whereas lignin, tannins,and aromatic substances served as the main components. The results of cluster analysis revealed that the soil properties in Jiangxi Province were considerably different from those in other regions. The key backgrounds of the DOM molecular characteristics in the vegetablefield soil samples across China' Mainland were provided at the molecular level, with large abundance and great variability.展开更多
Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction ...Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR).In this work,a threedimensional(3D)defect-rich bifunctional electrocatalyst(CoFe/N CNFs)comprising irregular hollow CoFe nanospheres in Ndoped carbon nanofibers is presented,which is fabricated from CoFe ZIFs-derived(ZIF:zeolitic-imidazolate framework)polymer nanofibers precursor.The CoFe ZIFs with tunable particle size and composition are constructed using a confined synthesis strategy.Moreover,the Kirkendall diffusion process is available for forming the irregular hollow CoFe nanospheres,and the decomposition of polyvinylpyrrolidone(PVP)results in forming the defective carbon nanofibers,which provide more efficient active sites and enhance the electrocatalytic properties toward both OER and ORR.The optimized CoFe/N CNFs exhibit superior bifunctional activities,outperforming that of the benchmark Pt/C+RuO_(2) catalyst.As a result,the CoFe/N CNFs as an air-cathode endow the rechargeable Zn-air battery with an excellent power density of 149 mW·cm^(−2),energy density of 875 Wh·kg^(−1),and cycling stability.This work provides a new strategy to develop bifunctional electrocatalysts with desired nanostructure and regulated performance toward energy applications.展开更多
文摘Objective: To investigate the clinicopathological features, survival and prognostic factors for gastroenteropancreatic neuroendocrine neoplasms(GEP-NENs) in a Chinese population.Methods: We investigated 154 consecutive patients(88 males, 66 females; median age 56 years, age range 9-86 years) diagnosed with GEP-NENs between 2001 and 2013 at The Affiliated Hospital of Qingdao University. Demographic, clinical and pathological variables and survival data were retrieved.Results: The pancreas was the most common site of involvement(63/154, 40.9%). Tumor size varied from 0.3 to 16.0 cm(median, 1.2 cm). The patients were followed up for a median period of 22 months(range, 1-157 months). The estimated 3- and 5-year overall survival(OS) rates for all patients were 84.0% and 81.9%, respectively. Multivariate analysis showed that larger tumor size, lymphatic metastases and distant metastases were significant predictors for poor survival outcome.Conclusions: Our data provide further information on the clinicopathological features of GEP-NENs in China. Additionally, we identified tumor size, lymphatic metastases and distant metastases as independent prognostic factors for long-term survival.
基金Supported by the Guangdong Natural Science Foundation(2016A030313294).
文摘Background:The usage of the light emitting diode(LED)has been increasingly applied in the illumination setting and electronic equipment.However,the effect of LED lights on the retina remains unclear.In this study,we observed and analyzed the impact of white LED lights at different intensities on the function and morphology of rat retinas.Methods:Thirty-six Sprague-Dawley rats weighing 150-180 g were randomly divided into six groups(n=6 in each group)including a normal control(NC)group,4 white LED groups at different light intensities(4,000,6,000,7,000,and 10,000 lux),and an ultraviolet B(UVB)lighting group(302 nm,1,000μw/cm2).After 24 hours of continuous illumination,full-field flash electroretinogram(FERG)and pathological examination were performed in each group.Results:As revealed by FERG,the impairment of retinal function gradually worsened with the increase of LED light intensity.In contrast,the UVB group had the most severe retinal function impairment.Particularly,the functional damage of rod cells and inner nuclear layer cells was the main FERG finding in each group.In the NC group,the retina had typical morphologies featured by well-defined structures,clearly visible border between the inner and outer segments,and neatly arranged inner and outer nuclear layer cells.After 24 hours of illumination,the inner and outer parts of the retina in the 4,000 lux group were still neatly arranged,along with a clear border;however,the inner and outer nuclear layers were randomly arranged,and some irregular nuclei and cells were lost.The damage of the internal and external retinal segments and the internal and external nuclear layers became more evident in the 6,000 lux group,7,000 lux group,and 10,000 lux group.The UVB group had a more obviously disordered arrangement of inner and outer nuclear layers and loss of cells.Conclusions:Continuous exposure to white LED light can cause structural and functional damage to rat retinas,and such damage is related to the intensity of illumination.Therefore,the risk of retinal damage should be considered during LED illumination,and proper LED illumination intensity may help to maintain eye health.
基金Supported by the Guangdong Natural Science Foundation(2016A030313294).
文摘Background:To investigate the effect of sirolimus(SRL)eye drops on acute alkali-burn-induced corneal neovascularization(CNV)and explore its possible mechanism.Methods:A total of 57 male Sprague-Dawley rats weighing 160-180 g were randomly divided into four groups including a normal control group(NC group,n=12),an untreated alkali-burned model control group(MC group,n=15),a blank eye drop treatment group(BT group,n=15),and an SRL eye drop treatment group(ST group,n=15).Corneal inflammation and CNV were observed and scored under a slit-lamp microscope 3,7,and 14 days after alkali exposure.Three rats were randomly sacrificed in each group before modeling and 3,7,14 days after modeling,and the corneas of right eyes were harvested for Western blotting to compare the expression levels of VEGFR2 and caspase-3.Results:Corneal inflammation scoring showed that the corneal edema and conjunctival congestion were severe in the MC,BT,and ST groups 1 day after alkali exposure but were alleviated at day 3.The corneal transparency was significantly higher in the ST group than in the MC and BT groups at days 7(F=9.77,P<0.05)and 14(F=5.81,P<0.05).At day 1,the corneal limbal vascular network was markedly filled.SNV was obvious at days 3,7,and 14.The new blood vessels were shorter and sparser in the ST group than in the MC and BT groups,and the CNV scores showed significant differences among these groups(day 3:F=8.60,P<0.05;day 7:F=11.40,P<0.05;and day 14:F=41.59,P<0.01).Western blotting showed that the expressions of VEGFR2 and caspase-3 were low before modeling and showed no significant difference among the different groups(F=0.52,P>0.05;F=0.98,P>0.05).The corneal expression of VEGFR2 became significantly higher in the MC and BT groups than in the ST group 3,7,and 14 days after alkali exposure,and there were significant differences in relative gray-scale values among these groups(day 3:F=32.16,P<0.01;day 7:F=85.96,P<0.01;day 14:F=57.68,P<0.01).The increase in the corneal expression of caspase-3 was significantly larger in the ST group than in the MC and BT groups at days 3,7,and 14,and there were significant differences in relative gray-scale values among groups(day 3:F=32.16,P<0.01;day 7:F=53.02,P<0.01;day 14:F=38.67,P<0.01).Conclusions:SRL eye drops can alleviate acute alkali-burn-induced corneal inflammation and inhibit alkali-burn-induced CNV in rat models.It can reduce VEGFR2 expression and increase caspase-3 expression in the corneal tissue,which may contribute to the inhibition of alkali-burn-induced CNV.
文摘Objective: The aim of the study was to analyze the clinicopathologic characteristics of gastroenteropancreatic neuroendocrine neoplasm(GEP-NEN) and to explore the prognostic factors for patients and differences of immunohistochemical markers between neuroendocrine tumor(NET) and neuroendocrine carcinoma(NEC). Methods: Retrospective reviews were conducted for the charts of 119 patients with GEP-NEN at the Affiliated Hospital of Qingdao University(China) from August 2003 to December 2013. Kaplan-Meier method was used to do the overall survivals analysis for the patients at different levels of predictive factors. Meanwhile, Cox proportional hazard model was used to select independent risk factors of survival. Analysis of variance was used to compare the expression of immunohistochemical markers among different pathological grades. Results: Among 119 patients, pancreas(45/119, 37.82%) and rectum(33/119, 27.73%) were mostly involved. The onset age of GEP-NEN in female group was younger than that of the male group. There were 13 deaths(10.92%) during 18.9(0.1–133.4) months follow-up period. Multivariate analysis indicated that neural invasion, gender and pathological grades of NET and NEC were independent risk factors. In neuroendocrine neoplasm(NEN), Syn expression in G2 was higher than G1 and G3, while Cg A showed no significant difference. All markers showed no significant differences between NET and NEC. Conclusion: GEP-NEN may occur at multiple sites of digestive system and lack specific clinical manifestations. Syn expression detected for the prognosis of G1, G2 and G3 tumors have clinical significance. Neural invasion, sex and pathological grades were independent prognostic factors for GEP-NEN patients. No significant difference was found in different pathological grades of NET and NEC.
文摘Objective: The aim of this study was to investigate the expressions of CD147 and CK19 in hepatocellular car- cinoma (HCC) and their clinical significance. Methods: The expressions of CD147 and CK19 were determined by tissue microarray and immunohistochemistry (IHC) in 272 cases of HCC and 81 cases of adjacent tumorous tissue. Results: The positive expression of CD147 in HCC and adjacent tumorous tissue was 73.53% (200/272) and 13.58% (11/81) with signifi- cant difference (P < 0.05). The positive expression of CK19 in HCC and adjacent tumorous tissue was 14.34% (39/272) and 0 (0/81) with significant difference (P < 0.05). The positive expression of CD147 were closely correlated to the histological grade, clinical stage, tumor-free survival, diameter of tumor and embolus of cancer in aqueduct or portal vein; but not to the patients' sex, age, liver cirrhosis, AFP level, infection of HBV, lymph node metastasis, number of tumor, invasion liver involucrum and the micro-satellites (P > 0.05). The expression of CK19 in HCC were closely correlate to the tumor-free survival, histological grade, diameter of tumor, liver cirrhosis, micro-satellites, lymph node metastasis and clinical stage; but not to patients' sex, age, number of tumor, invasion liver involucrum, AFP level, infection of HBV and embolus of cancer in aqueduct or portal vein (P > 0.05). Among the patients of positive expression of CD147, the median replacing time and overall survival were 13 and 24 months, lower than 48 and 60 months in the patients of negative expression (P < 0.05). Among the patients of positive expression of CK19, the median replacing time and overall survival were 7 and 13 months, lower than 31 and 42 months in the patients of negative expression (P < 0.05). The expression of CD147 had no correlation with the expression of CK19 (r = 0.061, P = 0.317). Conclusion: The positive of CD147 and CK19 closely correlate with the clinical prognosis of HCC, it may indicate poor prognosis of HCC.
基金the National Natural Science Foundation of China(No.11902256)the Natural Science Basic Research Program of Shaanxi,China(No.2019JQ-479).
文摘A novel grooving method for eliminating the bending-induced collapse of hexagonal honeycombs has been proposed,which lies in determining the appropriate grooving parameters,including the grooving spacing,angle,and depth.To this end,a framework built upon the experiment-based,machine learning approach for grooving parameters prediction was presented.The continuously grooved honeycomb bending experiments with various radii,honeycomb types,and thicknesses were carried out,and then the deformation level of honeycombs at different grooving spacing was quantitatively evaluated.A criterion for determining the grooving spacing was proposed by setting an appropriate tolerance for the out-of-plane compression strength.It was found that as the curvature increases,the grooving spacing increases due to the deformation level of honeycombs being more severe at a smaller bending radius.Besides,the grooving spacing drops as the honeycomb thickness increases,and the cell size has a positive effect on the grooving spacing,while the relative density has a negative effect on the grooving spacing.Furthermore,the data-driven Gaussian Process(GP)was trained from the collected data to predict the grooving spacing efficiently.The grooving angle and depth were calculated using the geometrical relationship of honeycombs before and after bending.Finally,the grooving parameters design and verification of a honeycomb sandwich fairing part were conducted based on the proposed grooving method.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program (STEP,No.2019QZKK0304)the Fundamental Research Funds for the Central Universities (No.E2EG0502×2)the Natural Science Foundation Committee of China (No.41991310)。
文摘Dissolved organic matter(DOM) plays an essential role in many geochemical processes,however its complexity, chemical diversity, and molecular composition are poorly understood. Soil samples were collected from 500 vegetable fields in administrative regions of China' Mainland, of which 122 were selected for further investigation. DOM properties were characterized by three-dimensional excitation-emission matrix(3D-EEM) fuorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry(FTICRMS)(field intensity is 15 Tesla). Our results indicated that the main constituents were UVA humic-like substances, humic-like substances, fulvic acid-like substances, and tyrosine-like substances. A total of 10,989 molecular formulae with a mass range of 100.04 to 799.59 Da were detected, covering the mass spectrometric information of the soil samples from 27 different regions. CHO and CHON molecules were dominant in DOM, whereas lignin, tannins,and aromatic substances served as the main components. The results of cluster analysis revealed that the soil properties in Jiangxi Province were considerably different from those in other regions. The key backgrounds of the DOM molecular characteristics in the vegetablefield soil samples across China' Mainland were provided at the molecular level, with large abundance and great variability.
基金supported by the National Natural Science Foundation of China(Nos.11902256 and 51573148)the Natural Science Basic Research Program of Shaanxi(No.2019JQ-479)+2 种基金the Key Research and Development Program of Shaanxi Province(No.2020ZDGY01-01)the Fundamental Research Funds for the Central Universities(No.D5000220202)the China Scholarship Council and thanks eceshi(www.eceshi.com)for the Raman analysis.
文摘Zn-air batteries with high energy density and safety have acquired enormous attention,while the practical application is hindered by the sluggish kinetics of the oxygen evolution reaction(OER)and the oxygen reduction reaction(ORR).In this work,a threedimensional(3D)defect-rich bifunctional electrocatalyst(CoFe/N CNFs)comprising irregular hollow CoFe nanospheres in Ndoped carbon nanofibers is presented,which is fabricated from CoFe ZIFs-derived(ZIF:zeolitic-imidazolate framework)polymer nanofibers precursor.The CoFe ZIFs with tunable particle size and composition are constructed using a confined synthesis strategy.Moreover,the Kirkendall diffusion process is available for forming the irregular hollow CoFe nanospheres,and the decomposition of polyvinylpyrrolidone(PVP)results in forming the defective carbon nanofibers,which provide more efficient active sites and enhance the electrocatalytic properties toward both OER and ORR.The optimized CoFe/N CNFs exhibit superior bifunctional activities,outperforming that of the benchmark Pt/C+RuO_(2) catalyst.As a result,the CoFe/N CNFs as an air-cathode endow the rechargeable Zn-air battery with an excellent power density of 149 mW·cm^(−2),energy density of 875 Wh·kg^(−1),and cycling stability.This work provides a new strategy to develop bifunctional electrocatalysts with desired nanostructure and regulated performance toward energy applications.
