The theoretical analysis of springback in rotary stretch bending process of L-section extrusion was studied. The models for characterizing the springback angle after unloading were established based on the stress and ...The theoretical analysis of springback in rotary stretch bending process of L-section extrusion was studied. The models for characterizing the springback angle after unloading were established based on the stress and strain distributions in the cross-section of the part. With the proposed model, analysis of the effect of pre-stretch force and post-stretch force on springback angle shows that springback decreases as the pre-stretch force or post-stretch force increases. Comparative study with experiments clearly demonstrates that the prediction of springback can resort to the current model without the loss of accuracy.展开更多
Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the q...Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the quantitative perspective. Based on the vector data of land use in 1990, 2000 and 2009 of Yantai Proper, Shandong Province China, 11 explanatory variables were chosen from two aspects: the elevation, slope, cost distance to major water area and cost distance to minor water area, which presented physical factors; cost distance to district center, cost distance to town center, cost distance to city expansion center, cost distance to major roads, cost distance to city roads, cost distance to county roads and cost distance to rural roads, which presented the socio-economic factors. Combined with spatial analysis tools and Logistic regression analysis model, we construct Logistic regression analyses with four objectives that were urban construction land, rural residential land, orchard and other lands. The results show that, cost distance to district center, cost distance to town center, cost distance to city expansion center and cost distance to city roads are the significant explanatory variables for the transition of cultivated land into urban construction land. The main explained factors on the transition of cultivated land into rural residential land are slope, cost distance to town center, cost distance to county roads and cost distance to rural roads. Slope, cost distance to minor water area, cost distance to town center, cost distance to county roads and cost distance to rural roads are the significant explanatory variables for the transition of cultivated land into orchard land. Elevation, slope, cost distance to major water area and cost distance to minor water area are the main explanatory variables on the transition of cultivated land into other land uses.展开更多
The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated ...The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated by discrete element method(DEM) in three dimensions under variant rotation speeds,filling degree,based on the background of induration process of iron ore pellets.The influences of the mentioned factors on the maximum thickness of the active layer and the average velocity of particles have been investigated.The average velocity of particles increases with Froude number following the power function over a wide range,and the maximum thickness rises with increasing rotation speed in a way of logarithm.The influence of the filling degree f on the maximum thickness exhibits a good linearity under two classic regimes,but the increasing of the average velocity of the active layer is limited at f=0.4.This basic research highlights the impact of the active layer within rotary kilns,and lays a good foundation for the further investigation in mixing and heat transfer within the particle bed inside rotary kilns.展开更多
We have investigated the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions byconsidering the particle shape effect. In particular, we consider coated oblate spheroidal particles and presen...We have investigated the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions byconsidering the particle shape effect. In particular, we consider coated oblate spheroidal particles and present a theoreticalstudy of ER based on the spectral representation theory. Analytic expressions for the characteristic frequency as wellas the dispersion strength can be obtained, thus simplifying the fitting of experimental data on oblate spheroidal cellsthat abound in the literature. From the theoretical analysis, we find that the cellshape, coating as well as materialparameters can change the ER spectrum. We demonstrate a good agreement between our theoretical predictions andexperimental data on human erthrocytes suspensions.展开更多
AIM:To investigate the association of obesity and elevated alanine aminotransferase with insulin resistance and compare these factors with metabolic syndrome. METHODS:We enrolled a total of 1308 male workers aged from...AIM:To investigate the association of obesity and elevated alanine aminotransferase with insulin resistance and compare these factors with metabolic syndrome. METHODS:We enrolled a total of 1308 male workers aged from 22 to 63 years.Data was extracted from the workers'periodic health check-ups in hospitals.All cases were from the community of northern Taiwan. This was a cross-sectional observational study from July to September in 2004.We grouped all cases into four groups,based on the quartile of homeostasis model assessment.The top fourth quartile group was defined as the group with insulin resistance.We performed multivariate logistic regression analysis for the odds ratio of the risk factors for insulin resistance. RESULTS:Compared with metabolic syndrome,the coexistence of both factors had a 4.3-fold(95%CI: 2.7-6.8)increased risk,which was more than metabolic syndrome with a 3.6-fold(95%CI:2.6-5.0)increased risk.The two factors had a synergistic effect.The synergistic index of obesity and elevated alanine aminotransferase(ALT)was 2.1(95%CI:1.01-4.3).CONCLUSION:Obesity and elevated ALT are associatedwith insulin resistance.The effects are synergistic. Coexistence of them is better than metabolic syndrome in predicting insulin resistance.展开更多
AIM： To explore epigenetic changes in the gene encod- ing X chromosome-linked inhibitor of apoptosis-associ- ated factor 1 （XAF1） during esophageal carcinogenesis. METHODS： Methylation status of XAF1 was detected ...AIM： To explore epigenetic changes in the gene encod- ing X chromosome-linked inhibitor of apoptosis-associ- ated factor 1 （XAF1） during esophageal carcinogenesis. METHODS： Methylation status of XAF1 was detected by methylation-specific polymerase chain reaction （MSP） in four esophageal cancer cell lines （KYSE30, KYSE70, BICl and partially methylated in TE3 cell lines）, nine cases of normal mucosa, 72 cases of pri- mary esophageal cancer and matched adjacent tissue. XAF1 expression was examined by semi-quantitative reverse transcriptional polymerase chain reaction and Western blotting before and after treatment with 5-aza- deoxycytidine （5-aza-dc）, a demethylating agent. To investigate the correlation of XAF1 expression and methylation status in primary esophageal cancer, immu- nohistochemistry for XAF1 expression was performed in 32 cases of esophageal cancer and matched adjacent tissue. The association of methylation status and clini-copathological data was analyzed by logistic regression. RESULTS： MSP results were as follows： loss of XAF1 expression was found in three of four esophageal cell lines with promoter region hypermethylation （com- pletely methylated in KYSE30, KYSE70 and BIC1 cell lines and partially in TE3 cells）; all nine cases of normal esophageal mucosa were unmethylated; and 54/72 （75.00%） samples from patients with esophageal can- cer were methylated, and 25/72 （34.70%） matched adjacent tissues were methylated （75.00% vs 34,70%, z2 = 23.5840, P = 0.000）. mRNA level of XAF1 mea- sured with semi-quantitative reverse transcription poly- merase chain reaction was detectable only in TE3 cells, and no expression was detected in KYSE30, KYSE70 or BIC1 cells. Protein expression was not observed in KYSE30 cells by Western blotting before treatment with 5-aza-dc. After treatment, mRNA level of XAF1 was detectable in KYSE30, KYSE70 and BIC1 cells. Protein expression was detected in KYSE30 after treatment with 5-aza-dc. Immunohistochemistry was performed on 32 cases of esophageal cancer and adjacent tissue, and demonstrated XAF1 in the nucleus and cytoplasm. XAF1 staining was found in 20/32 samples of adjacent normal tissue but was present in only 8/32 samples of esophageal cancer tissue （Z2= 9.143, P = 0.002）. XAF1 expression was decreased in cancer samples compared with adjacent tissues. In 32 cases of esophageal can- cer, 24/32 samples were methylated, and 8/32 esopha- geal cancer tissues were unmethylated. XAF1 staining was found in 6/8 samples of unmethylated esophageal cancer and 2/24 samples of methylated esophageal cancer tissue. XAF1 staining was inversely correlated with XAF1 promoter region methylation （Fisher＇s exact test, P = 0.004）. Regarding methylation status and clinicopathological data, no significant differences were found in sex, age, tumor size, tumor stage, or metas- tasis with respect to methylation of XAF1 for the 72 tis- sue samples from patients with esophageal cancer. CONCLUSION： XAF1 is frequently methylated in eso- phageal cancer, and XAF1 expression is regulated by promoter region hypermethylation.展开更多
The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling inst...The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling instability is not considered in the design codes. In this paper, the effect of web opening on both lateral torsional buckling and local buckling behaviors has been investigated. A simply supported steel I-beam has been studied under uniform bending moment around the major axis. Buckling analysis has been performed using the finite element method. Linear regression analysis has been conducted for output data to formulate an equation for the critical moment including web opening effect. The results have shown a limited reduction in the lateral torsional buckling capacity and a significant reduction in the local buckling capacity.展开更多
AIM:To evaluate the possibility of an association between polyethylene glycol(PEG) and acute renal failure(ARF) in elderly patients using a health insurance claims database.METHODS:We conducted a population-based case...AIM:To evaluate the possibility of an association between polyethylene glycol(PEG) and acute renal failure(ARF) in elderly patients using a health insurance claims database.METHODS:We conducted a population-based casecrossover study using information obtained from Korean Health Insurance Review and Assessment Service(HIRA) claims from January 1,2005 to December 31,2005(Seoul,Korea).The study population consisted of elderly patients who received PEG prior to experiencing their first ARF-related hospitalization from April 1,2005 to December 31,2005.For each patient,one case and two control periods were matched.PEG use in a 2-or 4-wk window period prior to hospitalization for ARF was compared with PEG use in two earlier 2-or 4-wk control window periods.Conditional logistic regression analysis was used to estimate odds ratios(ORs) and 95% CI,adjusting for concomitant uses of diuretics,angiotensin converting enzyme inhibitors,non-steroidal anti-inflammatory drugs,antibiotics,anti-cancer drugs,and contrast media.RESULTS:Within the HIRA database which contained 1 093 262 elderly patients,1156 hospitalized ARF cases were identified.Among these cases,PEG was prescribed to 17(1.5%) patients before hospitalization.The adjusted ORs when applying the 2-and 4-wk window periods were 0.4(95% CI:0.03-5.24) and 2.1(95% CI:0.16-27.78),respectively.CONCLUSION:No increased risk of ARF was found in elderly PEG users.However,based on the limited number of study subjects,further analysis should be performed to confirm these results.展开更多
This study investigates the spatial differences and the factors influencing those differences as they affect forest transitions in the Qian-Gui Karst Mountain areas to provide references for policy makers,and ideas fo...This study investigates the spatial differences and the factors influencing those differences as they affect forest transitions in the Qian-Gui Karst Mountain areas to provide references for policy makers,and ideas for ecological environmental protection strategies and adaptive management strategies for forest restoration projects in mountain areas.Forest transition characteristics are determined in relationship to spatial and functional transitions.SPSS and a geographical detector are used to analyze the forces driving forest transitions in terms of natural environmental and socio-economic factors.The results were as follows:(1)The area of forestland in the Qian-Gui Karst Mountain areas increased by 673.5 km^2 during 1990-2015,and a U-shaped curve generally describes the tendency of this change.More precisely,forest land area decreased initially and increased later,with the turning point occurring in the year 2000.This suggests that the Qian-Gui Karst Mountain areas are being maintained at a later stage of forest transition,and this means they are experiencing a net increase in forest land area.The average annual rainfall and temperature,distance to the nearest river and nearest rural residential area,amplitude of topographical relief,and slope contributed the most to forest spatial transitions.(2)During the study period,the tendency for forest coverage to change varied considerably in different parts of the study area,and the greatest increase occurred in the area of very high forest coverage,an area of 154173.71 km^2.The ranking of other forest coverages tended to decrease during the past 25 years.The vegetation ecosystem,in general,is being maintained in the process of restoration,and changes in the ranking of forest coverage were high in the northern part of the study area and low in the southern part.Forest spatial transitions were affected by the interaction between natural environmental and socio-economic factors,and the average annual temperature and rainfall,elevation,and lighting intensity at night were the most important factors that governed forest functional transitions.An examination of the direction in which spatial and functional transitions are moving in the forest area indicates that ecological construction,rather than spatial expansion of the forest area,should be used in the future to improve forest quality.展开更多
Background:The prognosis for patients with colorectal-cancer liver metastases(CRLM)after curative surgery remains poor and shows great heterogeneity.Early recurrence,defined as tumor recurrence within 6 months of cura...Background:The prognosis for patients with colorectal-cancer liver metastases(CRLM)after curative surgery remains poor and shows great heterogeneity.Early recurrence,defined as tumor recurrence within 6 months of curative surgery,is associated with poor survival,requiring earlier detection and intervention.This study aimed to develop and validate a bedside model based on clinical parameters to predict early recurrence in CRLM patients and provide insight into post-operative surveillance strategies.Material and methods:A total of 202 consecutive CRLM patients undergoing curative surgeries between 2012 and 2019 were retrospectively enrolled and randomly assigned to the training(n=150)and validation(n=52)sets.Baseline information and radiological,pathological,and laboratory findings were extracted from medical records.Predictive factors for early recurrence were identified via a multivariate logistic-regression model to develop a predictive nomogram,which was validated for discrimination,calibration,and clinical application.Results:Liver-metastases number,lymph-node suspicion,neurovascular invasion,colon/rectum location,albumin and post-operative carcinoembryonic antigen,and carbohydrate antigen 19–9 levels(CA19–9)were independent predictive factors and were used to construct the nomogramfor early recurrence after curative surgery.The area under the curve was 0.866 and 0.792 for internal and external validation,respectively.The model significantly outperformed the clinical risk score and Beppu’s model in our data set.In the lift curve,the nomogram boosted the detection rate in post-operative surveillance by two-fold in the top 30%high-risk patients.Conclusion:Our model for early recurrence in CRLM patients after curative surgeries showed superior performance and could aid in the decision-making for selective follow-up strategies.展开更多
基金Project (20090450276) supported by the China Postdoctoral Science FoundationProject (50905008) supported by the National Natural Science Foundation of China
文摘The theoretical analysis of springback in rotary stretch bending process of L-section extrusion was studied. The models for characterizing the springback angle after unloading were established based on the stress and strain distributions in the cross-section of the part. With the proposed model, analysis of the effect of pre-stretch force and post-stretch force on springback angle shows that springback decreases as the pre-stretch force or post-stretch force increases. Comparative study with experiments clearly demonstrates that the prediction of springback can resort to the current model without the loss of accuracy.
基金Under the auspices of National Natural Science Foundation of China(No.41130748)
文摘Cultivated land transition and its driving mechanism are the hotspots among studies on land use change. In this study, we constructed a framework to study the driving mechanism of cultivated land transition from the quantitative perspective. Based on the vector data of land use in 1990, 2000 and 2009 of Yantai Proper, Shandong Province China, 11 explanatory variables were chosen from two aspects: the elevation, slope, cost distance to major water area and cost distance to minor water area, which presented physical factors; cost distance to district center, cost distance to town center, cost distance to city expansion center, cost distance to major roads, cost distance to city roads, cost distance to county roads and cost distance to rural roads, which presented the socio-economic factors. Combined with spatial analysis tools and Logistic regression analysis model, we construct Logistic regression analyses with four objectives that were urban construction land, rural residential land, orchard and other lands. The results show that, cost distance to district center, cost distance to town center, cost distance to city expansion center and cost distance to city roads are the significant explanatory variables for the transition of cultivated land into urban construction land. The main explained factors on the transition of cultivated land into rural residential land are slope, cost distance to town center, cost distance to county roads and cost distance to rural roads. Slope, cost distance to minor water area, cost distance to town center, cost distance to county roads and cost distance to rural roads are the significant explanatory variables for the transition of cultivated land into orchard land. Elevation, slope, cost distance to major water area and cost distance to minor water area are the main explanatory variables on the transition of cultivated land into other land uses.
基金Project(FRF-AS-10-0058) supported by the Fundamental Research Funds for the Central Universities,China
文摘The behavior of the active layer of material bed within rotary kilns plays a key role in industrial applications.To obtain its influences on industrial process,different regimes of particle motion have been simulated by discrete element method(DEM) in three dimensions under variant rotation speeds,filling degree,based on the background of induration process of iron ore pellets.The influences of the mentioned factors on the maximum thickness of the active layer and the average velocity of particles have been investigated.The average velocity of particles increases with Froude number following the power function over a wide range,and the maximum thickness rises with increasing rotation speed in a way of logarithm.The influence of the filling degree f on the maximum thickness exhibits a good linearity under two classic regimes,but the increasing of the average velocity of the active layer is limited at f=0.4.This basic research highlights the impact of the active layer within rotary kilns,and lays a good foundation for the further investigation in mixing and heat transfer within the particle bed inside rotary kilns.
文摘We have investigated the pressure effect on the eletrorotation (ER) spectrum of living cell suspensions byconsidering the particle shape effect. In particular, we consider coated oblate spheroidal particles and present a theoreticalstudy of ER based on the spectral representation theory. Analytic expressions for the characteristic frequency as wellas the dispersion strength can be obtained, thus simplifying the fitting of experimental data on oblate spheroidal cellsthat abound in the literature. From the theoretical analysis, we find that the cellshape, coating as well as materialparameters can change the ER spectrum. We demonstrate a good agreement between our theoretical predictions andexperimental data on human erthrocytes suspensions.
文摘AIM:To investigate the association of obesity and elevated alanine aminotransferase with insulin resistance and compare these factors with metabolic syndrome. METHODS:We enrolled a total of 1308 male workers aged from 22 to 63 years.Data was extracted from the workers'periodic health check-ups in hospitals.All cases were from the community of northern Taiwan. This was a cross-sectional observational study from July to September in 2004.We grouped all cases into four groups,based on the quartile of homeostasis model assessment.The top fourth quartile group was defined as the group with insulin resistance.We performed multivariate logistic regression analysis for the odds ratio of the risk factors for insulin resistance. RESULTS:Compared with metabolic syndrome,the coexistence of both factors had a 4.3-fold(95%CI: 2.7-6.8)increased risk,which was more than metabolic syndrome with a 3.6-fold(95%CI:2.6-5.0)increased risk.The two factors had a synergistic effect.The synergistic index of obesity and elevated alanine aminotransferase(ALT)was 2.1(95%CI:1.01-4.3).CONCLUSION:Obesity and elevated ALT are associatedwith insulin resistance.The effects are synergistic. Coexistence of them is better than metabolic syndrome in predicting insulin resistance.
基金Supported by Grants from the National Basic Research Program(973 Program), No. 2012CB934002, 2010CB912802National Key Scientific Instrument Special Programme of China, No.2011YQ03013405National Science Foundation of China,No. 81121004, 81071953 and 81161120432
文摘AIM： To explore epigenetic changes in the gene encod- ing X chromosome-linked inhibitor of apoptosis-associ- ated factor 1 （XAF1） during esophageal carcinogenesis. METHODS： Methylation status of XAF1 was detected by methylation-specific polymerase chain reaction （MSP） in four esophageal cancer cell lines （KYSE30, KYSE70, BICl and partially methylated in TE3 cell lines）, nine cases of normal mucosa, 72 cases of pri- mary esophageal cancer and matched adjacent tissue. XAF1 expression was examined by semi-quantitative reverse transcriptional polymerase chain reaction and Western blotting before and after treatment with 5-aza- deoxycytidine （5-aza-dc）, a demethylating agent. To investigate the correlation of XAF1 expression and methylation status in primary esophageal cancer, immu- nohistochemistry for XAF1 expression was performed in 32 cases of esophageal cancer and matched adjacent tissue. The association of methylation status and clini-copathological data was analyzed by logistic regression. RESULTS： MSP results were as follows： loss of XAF1 expression was found in three of four esophageal cell lines with promoter region hypermethylation （com- pletely methylated in KYSE30, KYSE70 and BIC1 cell lines and partially in TE3 cells）; all nine cases of normal esophageal mucosa were unmethylated; and 54/72 （75.00%） samples from patients with esophageal can- cer were methylated, and 25/72 （34.70%） matched adjacent tissues were methylated （75.00% vs 34,70%, z2 = 23.5840, P = 0.000）. mRNA level of XAF1 mea- sured with semi-quantitative reverse transcription poly- merase chain reaction was detectable only in TE3 cells, and no expression was detected in KYSE30, KYSE70 or BIC1 cells. Protein expression was not observed in KYSE30 cells by Western blotting before treatment with 5-aza-dc. After treatment, mRNA level of XAF1 was detectable in KYSE30, KYSE70 and BIC1 cells. Protein expression was detected in KYSE30 after treatment with 5-aza-dc. Immunohistochemistry was performed on 32 cases of esophageal cancer and adjacent tissue, and demonstrated XAF1 in the nucleus and cytoplasm. XAF1 staining was found in 20/32 samples of adjacent normal tissue but was present in only 8/32 samples of esophageal cancer tissue （Z2= 9.143, P = 0.002）. XAF1 expression was decreased in cancer samples compared with adjacent tissues. In 32 cases of esophageal can- cer, 24/32 samples were methylated, and 8/32 esopha- geal cancer tissues were unmethylated. XAF1 staining was found in 6/8 samples of unmethylated esophageal cancer and 2/24 samples of methylated esophageal cancer tissue. XAF1 staining was inversely correlated with XAF1 promoter region methylation （Fisher＇s exact test, P = 0.004）. Regarding methylation status and clinicopathological data, no significant differences were found in sex, age, tumor size, tumor stage, or metas- tasis with respect to methylation of XAF1 for the 72 tis- sue samples from patients with esophageal cancer. CONCLUSION： XAF1 is frequently methylated in eso- phageal cancer, and XAF1 expression is regulated by promoter region hypermethylation.
文摘The lateral torsional buckling phenomenon often governs design of steel I-beams. Although web opening is often used to accommodate the required mechanical and piping works in buildings, its effect on the buckling instability is not considered in the design codes. In this paper, the effect of web opening on both lateral torsional buckling and local buckling behaviors has been investigated. A simply supported steel I-beam has been studied under uniform bending moment around the major axis. Buckling analysis has been performed using the finite element method. Linear regression analysis has been conducted for output data to formulate an equation for the critical moment including web opening effect. The results have shown a limited reduction in the lateral torsional buckling capacity and a significant reduction in the local buckling capacity.
文摘AIM:To evaluate the possibility of an association between polyethylene glycol(PEG) and acute renal failure(ARF) in elderly patients using a health insurance claims database.METHODS:We conducted a population-based casecrossover study using information obtained from Korean Health Insurance Review and Assessment Service(HIRA) claims from January 1,2005 to December 31,2005(Seoul,Korea).The study population consisted of elderly patients who received PEG prior to experiencing their first ARF-related hospitalization from April 1,2005 to December 31,2005.For each patient,one case and two control periods were matched.PEG use in a 2-or 4-wk window period prior to hospitalization for ARF was compared with PEG use in two earlier 2-or 4-wk control window periods.Conditional logistic regression analysis was used to estimate odds ratios(ORs) and 95% CI,adjusting for concomitant uses of diuretics,angiotensin converting enzyme inhibitors,non-steroidal anti-inflammatory drugs,antibiotics,anti-cancer drugs,and contrast media.RESULTS:Within the HIRA database which contained 1 093 262 elderly patients,1156 hospitalized ARF cases were identified.Among these cases,PEG was prescribed to 17(1.5%) patients before hospitalization.The adjusted ORs when applying the 2-and 4-wk window periods were 0.4(95% CI:0.03-5.24) and 2.1(95% CI:0.16-27.78),respectively.CONCLUSION:No increased risk of ARF was found in elderly PEG users.However,based on the limited number of study subjects,further analysis should be performed to confirm these results.
基金The National Natural Science Foundation of China(41771115)The National Key Basic Research and Development Program(2015CB452706)The Guizhou “Thousand” Level Innovative Talents Support Project in 2015(111-0317003)
文摘This study investigates the spatial differences and the factors influencing those differences as they affect forest transitions in the Qian-Gui Karst Mountain areas to provide references for policy makers,and ideas for ecological environmental protection strategies and adaptive management strategies for forest restoration projects in mountain areas.Forest transition characteristics are determined in relationship to spatial and functional transitions.SPSS and a geographical detector are used to analyze the forces driving forest transitions in terms of natural environmental and socio-economic factors.The results were as follows:(1)The area of forestland in the Qian-Gui Karst Mountain areas increased by 673.5 km^2 during 1990-2015,and a U-shaped curve generally describes the tendency of this change.More precisely,forest land area decreased initially and increased later,with the turning point occurring in the year 2000.This suggests that the Qian-Gui Karst Mountain areas are being maintained at a later stage of forest transition,and this means they are experiencing a net increase in forest land area.The average annual rainfall and temperature,distance to the nearest river and nearest rural residential area,amplitude of topographical relief,and slope contributed the most to forest spatial transitions.(2)During the study period,the tendency for forest coverage to change varied considerably in different parts of the study area,and the greatest increase occurred in the area of very high forest coverage,an area of 154173.71 km^2.The ranking of other forest coverages tended to decrease during the past 25 years.The vegetation ecosystem,in general,is being maintained in the process of restoration,and changes in the ranking of forest coverage were high in the northern part of the study area and low in the southern part.Forest spatial transitions were affected by the interaction between natural environmental and socio-economic factors,and the average annual temperature and rainfall,elevation,and lighting intensity at night were the most important factors that governed forest functional transitions.An examination of the direction in which spatial and functional transitions are moving in the forest area indicates that ecological construction,rather than spatial expansion of the forest area,should be used in the future to improve forest quality.
基金supported by the Key Technology Research and Development Program of Zhejiang Province [No.2017C03017]the National Natural Science Foundation of China [81672916,11932017,81802750]+2 种基金the Natural Science Foundation of Zhejiang Province [LQ20H180014 to Y.Y.]the China Postdoctoral Science Foundation [2019M652117 to Y.Y.]the Natural Science Foundation of Zhejiang Province [LBY20H160002].
文摘Background:The prognosis for patients with colorectal-cancer liver metastases(CRLM)after curative surgery remains poor and shows great heterogeneity.Early recurrence,defined as tumor recurrence within 6 months of curative surgery,is associated with poor survival,requiring earlier detection and intervention.This study aimed to develop and validate a bedside model based on clinical parameters to predict early recurrence in CRLM patients and provide insight into post-operative surveillance strategies.Material and methods:A total of 202 consecutive CRLM patients undergoing curative surgeries between 2012 and 2019 were retrospectively enrolled and randomly assigned to the training(n=150)and validation(n=52)sets.Baseline information and radiological,pathological,and laboratory findings were extracted from medical records.Predictive factors for early recurrence were identified via a multivariate logistic-regression model to develop a predictive nomogram,which was validated for discrimination,calibration,and clinical application.Results:Liver-metastases number,lymph-node suspicion,neurovascular invasion,colon/rectum location,albumin and post-operative carcinoembryonic antigen,and carbohydrate antigen 19–9 levels(CA19–9)were independent predictive factors and were used to construct the nomogramfor early recurrence after curative surgery.The area under the curve was 0.866 and 0.792 for internal and external validation,respectively.The model significantly outperformed the clinical risk score and Beppu’s model in our data set.In the lift curve,the nomogram boosted the detection rate in post-operative surveillance by two-fold in the top 30%high-risk patients.Conclusion:Our model for early recurrence in CRLM patients after curative surgeries showed superior performance and could aid in the decision-making for selective follow-up strategies.
