The rational layout of urban commercial space is conducive to optimizing the allocation of commercial resources in the urban interior space. Based on the commercial POI (Point of Interest) data in the central district...The rational layout of urban commercial space is conducive to optimizing the allocation of commercial resources in the urban interior space. Based on the commercial POI (Point of Interest) data in the central district of Mianyang, the characteristics of urban commercial spatial pattern under different scales are analyzed by using Kernel Density Estimation, Getis-Ord , Ripley’s K Function and Location Entropy method, and the spatial agglomeration characteristics of various industries in urban commerce are studied. The results show that: 1) The spatial distribution characteristics of commercial outlets in downtown Mianyang are remarkable, and show a multi-center distribution pattern. The hot area distribution of commercial outlets based on road grid unit is generally consistent with the identified commercial density center distribution. 2) The commercial grade scale structure has been formed in the central urban area as a whole, and the distribution of commercial network hot spots based on road grid unit is generally consistent with the identified commercial density center distribution. 3) From the perspective of commercial industry, the differentiation of urban commercial space “center-periphery” is obvious, and different industries show different spatial agglomeration modes. 4) The multi-scale spatial agglomeration of each industry is different, the spatial scale of location choice of comprehensive retail, household appliances and other industries is larger, and the scale of location choice of textile, clothing, culture and sports is small. 5) There are significant differences in specialized functional areas from the perspective of industry. Mature areas show multi-functional elements, multi-advantage industry agglomeration characteristics, and a small number of developing areas also show multi-advantage industry agglomeration characteristics.展开更多
Objective:Prevention and early detection of colorectal cancer(CRC)can increase the chances of successful treatment and reduce burden.Various data mining technologies have been utilized to strengthen the early detectio...Objective:Prevention and early detection of colorectal cancer(CRC)can increase the chances of successful treatment and reduce burden.Various data mining technologies have been utilized to strengthen the early detection of CRC in primary care.Evidence synthesis on the model’s effectiveness is scant.This systematic review synthesizes studies that examine the effect of data mining on improving risk prediction of CRC.Methods:The PRISMA framework guided the conduct of this study.We obtained papers via Pub Med,Cochrane Library,EMBASE and Google Scholar.Quality appraisal was performed using Downs and Black’s quality checklist.To evaluate the performance of included models,the values of specificity and sensitivity were comparted,the values of area under the curve(AUC)were plotted,and the median of overall AUC of included studies was computed.Results:A total of 316 studies were reviewed for full text.Seven articles were included.Included studies implement techniques including artificial neural networks,Bayesian networks and decision trees.Six articles reported the overall model accuracy.Overall,the median AUC is 0.8243[interquartile range(IQR):0.8050-0.8886].In the two articles that reported comparison results with traditional models,the data mining method performed better than the traditional models,with the best AUC improvement of 10.7%.Conclusions:The adoption of data mining technologies for CRC detection is at an early stage.Limited numbers of included articles and heterogeneity of those studies implied that more rigorous research is expected to further investigate the techniques’effects.展开更多
BACKGROUND Studies have shown that sleep disorders are closely related to anxiety and depression,and the quality of life(QoL)of patients with sleep disorders is generally poor.AIM To examine the occurrence of sleep di...BACKGROUND Studies have shown that sleep disorders are closely related to anxiety and depression,and the quality of life(QoL)of patients with sleep disorders is generally poor.AIM To examine the occurrence of sleep disorders in people with coronary heart disease(CHD)and their relationships with QoL,depression,and anxiety.METHODS As per the sleep condition,240 CHD individuals were separated into two groups:non-sleep disorder group(n=128)and sleep disorder group(n=112).The selfrating anxiety scale(SAS),self-rating depression scale(SDS),and World Health Organization criteria for the Quality of Life Brief scale(WHOQOL-BREF)scores of the two groups were compared.Logistic regression method was used to analyze the independent risk factors of CHD patients with sleep disorders.Multivariate logistic regression analysis was employed to develop the risk prediction model.The association among the Pittsburgh Sleep Quality Index,SAS,and SDS was examined using Spearman’s correlation analysis.RESULTS The incidence of sleep disorder was 46.67%in 240 patients.The scores of SAS and SDS in the sleep disorder group were higher than those in the non-sleep disorder group,and the WHOQOL-BREF scores were lower than those in the non-sleep disorder group(P<0.05).The risk prediction model of sleep disturbances in CHD patients was constructed using the outcomes of multivariate logistic regression analysis,P=1/[1+e(-2.160+0.989×(female)+0.001×(new rural cooperative medical insurance)+2.219×(anxiety)+2.157×depression)].The results of a Spearman’s correlation study revealed that sleep quality was strongly adversely connected with the physiological field,psychological field,and social relation scores in QoL,and was considerably positively correlated with SAS and SDS(P<0.05).CONCLUSION A multivariate logistic regression model can better predict the occurrence of sleep disorders in CHD patients.Sleep disorders in CHD patients are significantly correlated with QoL,depression,and anxiety.展开更多
Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which...Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which greatly reduces the sweep efficiency of reservoirs.In this work,the plugging process by microspheres and nanospheres from the fracture to the matrix was simulated through core experiments.The plugging performance of multi-scale microspheres(microspheres and nanospheres)on the core matrix was evaluated by measuring the plugging rate and other parameters.Enhanced oil recovery after synergistic plugging with multi-scale microspheres was used as the evaluation index,a sensitivity analysis of injection parameters was performed,and the best combination of injection parameters was optimized by orthogonal experiments.The experimental results showed that the plugging performance of nanospheres is mainly reflected in thefilling of the core matrix,while the plugging performance of microspheres is mainly reflected by retention at the injection end of the core(as opposed to the fractured end face).The plugging rate of nanospheres reached 78.83%,which is much higher than the 30.28%rate achieved with microspheres.The maximum oil recovery after plugging was 19.12%,which corresponds to the following combination of injection parameters:total injection of 0.6 pore volume(PV),injection ratio between nanospheres and microspheres of 2:1,injection rate of 1.5 mL$min 1,and aging time of 6 days.Among the injection parameters,the injection ratio between nanospheres and microspheres had the greatest influence on the recovery of waterflooding after plugging,followed by the total injection of multi-scale microspheres.The injection rate and aging time had little effect.展开更多
Oil transport is greatly affected by heterogeneous pore–throat structures present in shale.It is therefore very important to accurately characterize pore–throat structures.Additionally,it remains unclear how pore–t...Oil transport is greatly affected by heterogeneous pore–throat structures present in shale.It is therefore very important to accurately characterize pore–throat structures.Additionally,it remains unclear how pore–throat structures affect oil transport capacity.In this paper,using finite element(FE)simulation and mathematical modeling,we calculated the hydrodynamic resistance for four pore–throat structure.In addition,the influence of pore throat structure on shale oil permeability is analyzed.According to the results,the hydrodynamic resistance of different pore throat structures can vary by 300%.The contribution of additional resistance caused by streamline bending is also in excess of 40%,even without slip length.Fur-thermore,Pore–throat structures can affect apparent permeability by more than 60%on the REV scale,and this influence increases with heterogeneity of pore size distribution,organic matter content,and organic matter number.Clearly,modeling shale oil flow requires consideration of porous–throat structure and additional resistance,otherwise oil recovery and flow capacity may be overestimated.展开更多
Brugada syndrome(BrS)is an arrhythmogenic disorder which was first described in 1992.This disease is a channelopathy characterized by ST-segment elevations in the right precordial leads and is susceptible to sudden de...Brugada syndrome(BrS)is an arrhythmogenic disorder which was first described in 1992.This disease is a channelopathy characterized by ST-segment elevations in the right precordial leads and is susceptible to sudden death.BrS is a fatal disease with gender and age preferences.It occurs mainly in young male subjects with a structurally normal heart and silently progresses to sudden death with no significant symptoms.The prevalence of BrS has been reported in the ranges of 5-20 per 10000 people.The disease is more prevalent in Asia.Nowadays,numerous variations in 23 genes have been linked to BrS since the first gene SCN5A has been associated with BrS in 1998.Not only can clinical specialists apply these discoveries in risk assessment,diagnosis and personal medicine,but also forensic pathologists can make full use of these variations to conduct death cause identification.However,despite the progress in genetics,these associated genes can only account for approximately 35%of the BrS cases while the etiology of the remaining BrS cases is still unexplained.In this review,we discussed the prevalence,the genes associated with BrS and the application of molecular autopsy in forensic pathology.We also summarized the present obstacles,and provided a new insight into the genetic basis of BrS.展开更多
To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral...To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral sequence to prove the existence of a Bn-related family of homotopy elements, β1ωnγs, in the stable homotopy groups of spheres, where Bn〉 3, 3≤s〈 p-2 and the Bn-element was detected by X. Liu.展开更多
Studies regarding sport-related sudden cardiac death(SCD)mainly focus on competitive ath-letes;similar data are rare in the general population,especially in China.We conducted a retrospective study(from September 1998...Studies regarding sport-related sudden cardiac death(SCD)mainly focus on competitive ath-letes;similar data are rare in the general population,especially in China.We conducted a retrospective study(from September 1998 to August 2013)to investigate the aetiological distribution and epidemiological features of sport-related SCD in Southern China.Selections of cases are based on details,and two subgroups were established:one was the sport-related SCD group,and the other was the disease-free accident victims group which was matched with the sport-related SCD group in gender,age and year of death.Among the 3770 sudden-death cases,1656 cases were SCD cases.A total of 65 cases(57 males)out of 1656 SCD cases were sport-related.The age range of the 65 sport-related SCD cases was from 12 to 68 years old with a mean(35.92±14.23)years old.Only two of these cases were competitive athletes.The most common circumstances of the 65 sport-related SCD cases were heavy physical labour(46.15%)and running(30.77%).The three leading forensic diag-noses were the coronary atherosclerotic disease(CAD,28 cases),cardiomyopathy(CM,14 cases)and sudden unexplained death(7 cases).CM was the most common forensic diagno-sis in those?35 years old,while CAD was the most common one in those>35 years old.Left anterior descending in which atherosclerotic plaques was most commonly found was the principal artery branch associated with sport-related SCD.There was a statistically signifi-cant difference in the weight of hearts between the 65 sport-related SCD cases and 65 dis-eases-free accidental cases.This study highlights the need to attract public attention to sport-related SCD and to issue a prevention strategy to the public,and to make the SCD-related genetic sequencing a routine tool in both forensic pathological examination and clinic screening.展开更多
Autopsy is of great significance for elucidating the pathological changes,pathogenesis and cause of death of Coronavirus Disease 2019(COVID-19)and can provide a theoretical basis for scientific and accurate prevention...Autopsy is of great significance for elucidating the pathological changes,pathogenesis and cause of death of Coronavirus Disease 2019(COVID-19)and can provide a theoretical basis for scientific and accurate prevention and control of its outbreak.Based on related laws and regulations,such as the Law of the People's Republic of China on Prevention and Control of Infectious Diseases,clinical manifestations and epidemiological characteristics of COVID-19 and guidelines on the prevention and control of this epidemic,combined with the practical work of forensic pathology examinations,we developed the Guide to Forensic Pathology Practice for Death Cases Related to Coronavirus Disease 2019(COVID-19)(Trial Draft).This guide describes the background investigation of the death cases,autopsy room requirements,personal pre-vention and protections,external examinations,autopsy practices and auxiliary examinations,and thus offers a reference for forensic and pathological examination institutions and staff.展开更多
文摘The rational layout of urban commercial space is conducive to optimizing the allocation of commercial resources in the urban interior space. Based on the commercial POI (Point of Interest) data in the central district of Mianyang, the characteristics of urban commercial spatial pattern under different scales are analyzed by using Kernel Density Estimation, Getis-Ord , Ripley’s K Function and Location Entropy method, and the spatial agglomeration characteristics of various industries in urban commerce are studied. The results show that: 1) The spatial distribution characteristics of commercial outlets in downtown Mianyang are remarkable, and show a multi-center distribution pattern. The hot area distribution of commercial outlets based on road grid unit is generally consistent with the identified commercial density center distribution. 2) The commercial grade scale structure has been formed in the central urban area as a whole, and the distribution of commercial network hot spots based on road grid unit is generally consistent with the identified commercial density center distribution. 3) From the perspective of commercial industry, the differentiation of urban commercial space “center-periphery” is obvious, and different industries show different spatial agglomeration modes. 4) The multi-scale spatial agglomeration of each industry is different, the spatial scale of location choice of comprehensive retail, household appliances and other industries is larger, and the scale of location choice of textile, clothing, culture and sports is small. 5) There are significant differences in specialized functional areas from the perspective of industry. Mature areas show multi-functional elements, multi-advantage industry agglomeration characteristics, and a small number of developing areas also show multi-advantage industry agglomeration characteristics.
基金supported by the National Natural Science Foundation of China(No.71804183)。
文摘Objective:Prevention and early detection of colorectal cancer(CRC)can increase the chances of successful treatment and reduce burden.Various data mining technologies have been utilized to strengthen the early detection of CRC in primary care.Evidence synthesis on the model’s effectiveness is scant.This systematic review synthesizes studies that examine the effect of data mining on improving risk prediction of CRC.Methods:The PRISMA framework guided the conduct of this study.We obtained papers via Pub Med,Cochrane Library,EMBASE and Google Scholar.Quality appraisal was performed using Downs and Black’s quality checklist.To evaluate the performance of included models,the values of specificity and sensitivity were comparted,the values of area under the curve(AUC)were plotted,and the median of overall AUC of included studies was computed.Results:A total of 316 studies were reviewed for full text.Seven articles were included.Included studies implement techniques including artificial neural networks,Bayesian networks and decision trees.Six articles reported the overall model accuracy.Overall,the median AUC is 0.8243[interquartile range(IQR):0.8050-0.8886].In the two articles that reported comparison results with traditional models,the data mining method performed better than the traditional models,with the best AUC improvement of 10.7%.Conclusions:The adoption of data mining technologies for CRC detection is at an early stage.Limited numbers of included articles and heterogeneity of those studies implied that more rigorous research is expected to further investigate the techniques’effects.
基金Supported by Scientific Research Program on Chinese Medicine,No.2023460.
文摘BACKGROUND Studies have shown that sleep disorders are closely related to anxiety and depression,and the quality of life(QoL)of patients with sleep disorders is generally poor.AIM To examine the occurrence of sleep disorders in people with coronary heart disease(CHD)and their relationships with QoL,depression,and anxiety.METHODS As per the sleep condition,240 CHD individuals were separated into two groups:non-sleep disorder group(n=128)and sleep disorder group(n=112).The selfrating anxiety scale(SAS),self-rating depression scale(SDS),and World Health Organization criteria for the Quality of Life Brief scale(WHOQOL-BREF)scores of the two groups were compared.Logistic regression method was used to analyze the independent risk factors of CHD patients with sleep disorders.Multivariate logistic regression analysis was employed to develop the risk prediction model.The association among the Pittsburgh Sleep Quality Index,SAS,and SDS was examined using Spearman’s correlation analysis.RESULTS The incidence of sleep disorder was 46.67%in 240 patients.The scores of SAS and SDS in the sleep disorder group were higher than those in the non-sleep disorder group,and the WHOQOL-BREF scores were lower than those in the non-sleep disorder group(P<0.05).The risk prediction model of sleep disturbances in CHD patients was constructed using the outcomes of multivariate logistic regression analysis,P=1/[1+e(-2.160+0.989×(female)+0.001×(new rural cooperative medical insurance)+2.219×(anxiety)+2.157×depression)].The results of a Spearman’s correlation study revealed that sleep quality was strongly adversely connected with the physiological field,psychological field,and social relation scores in QoL,and was considerably positively correlated with SAS and SDS(P<0.05).CONCLUSION A multivariate logistic regression model can better predict the occurrence of sleep disorders in CHD patients.Sleep disorders in CHD patients are significantly correlated with QoL,depression,and anxiety.
基金funded by the NationalNatural Science Foundation of China(52274056,51974348).
文摘Advanced water injection has become an effective method for developing low-permeability reservoirs.However,after a period of high yield from fracturing,the injected waterflows rapidly along high-capacity channels,which greatly reduces the sweep efficiency of reservoirs.In this work,the plugging process by microspheres and nanospheres from the fracture to the matrix was simulated through core experiments.The plugging performance of multi-scale microspheres(microspheres and nanospheres)on the core matrix was evaluated by measuring the plugging rate and other parameters.Enhanced oil recovery after synergistic plugging with multi-scale microspheres was used as the evaluation index,a sensitivity analysis of injection parameters was performed,and the best combination of injection parameters was optimized by orthogonal experiments.The experimental results showed that the plugging performance of nanospheres is mainly reflected in thefilling of the core matrix,while the plugging performance of microspheres is mainly reflected by retention at the injection end of the core(as opposed to the fractured end face).The plugging rate of nanospheres reached 78.83%,which is much higher than the 30.28%rate achieved with microspheres.The maximum oil recovery after plugging was 19.12%,which corresponds to the following combination of injection parameters:total injection of 0.6 pore volume(PV),injection ratio between nanospheres and microspheres of 2:1,injection rate of 1.5 mL$min 1,and aging time of 6 days.Among the injection parameters,the injection ratio between nanospheres and microspheres had the greatest influence on the recovery of waterflooding after plugging,followed by the total injection of multi-scale microspheres.The injection rate and aging time had little effect.
基金supported by the National Natural Science Foundation of China(52274056,U22B2075).
文摘Oil transport is greatly affected by heterogeneous pore–throat structures present in shale.It is therefore very important to accurately characterize pore–throat structures.Additionally,it remains unclear how pore–throat structures affect oil transport capacity.In this paper,using finite element(FE)simulation and mathematical modeling,we calculated the hydrodynamic resistance for four pore–throat structure.In addition,the influence of pore throat structure on shale oil permeability is analyzed.According to the results,the hydrodynamic resistance of different pore throat structures can vary by 300%.The contribution of additional resistance caused by streamline bending is also in excess of 40%,even without slip length.Fur-thermore,Pore–throat structures can affect apparent permeability by more than 60%on the REV scale,and this influence increases with heterogeneity of pore size distribution,organic matter content,and organic matter number.Clearly,modeling shale oil flow requires consideration of porous–throat structure and additional resistance,otherwise oil recovery and flow capacity may be overestimated.
基金supported by the National Natural Science Foundation of China[grant number 81430046].
文摘Brugada syndrome(BrS)is an arrhythmogenic disorder which was first described in 1992.This disease is a channelopathy characterized by ST-segment elevations in the right precordial leads and is susceptible to sudden death.BrS is a fatal disease with gender and age preferences.It occurs mainly in young male subjects with a structurally normal heart and silently progresses to sudden death with no significant symptoms.The prevalence of BrS has been reported in the ranges of 5-20 per 10000 people.The disease is more prevalent in Asia.Nowadays,numerous variations in 23 genes have been linked to BrS since the first gene SCN5A has been associated with BrS in 1998.Not only can clinical specialists apply these discoveries in risk assessment,diagnosis and personal medicine,but also forensic pathologists can make full use of these variations to conduct death cause identification.However,despite the progress in genetics,these associated genes can only account for approximately 35%of the BrS cases while the etiology of the remaining BrS cases is still unexplained.In this review,we discussed the prevalence,the genes associated with BrS and the application of molecular autopsy in forensic pathology.We also summarized the present obstacles,and provided a new insight into the genetic basis of BrS.
基金supported by the National Natural Science Foundation of China(No.11571186)
文摘To determine the stable homotopy groups of spheres π＊（S） is one of the central problems in homotopy theory. Let p be a prime greater than 5. The authors make use of the May spectral sequence and the Adams spectral sequence to prove the existence of a Bn-related family of homotopy elements, β1ωnγs, in the stable homotopy groups of spheres, where Bn〉 3, 3≤s〈 p-2 and the Bn-element was detected by X. Liu.
基金This work was supported by the National Natural Science Foundation of China [grant number 81430046].
文摘Studies regarding sport-related sudden cardiac death(SCD)mainly focus on competitive ath-letes;similar data are rare in the general population,especially in China.We conducted a retrospective study(from September 1998 to August 2013)to investigate the aetiological distribution and epidemiological features of sport-related SCD in Southern China.Selections of cases are based on details,and two subgroups were established:one was the sport-related SCD group,and the other was the disease-free accident victims group which was matched with the sport-related SCD group in gender,age and year of death.Among the 3770 sudden-death cases,1656 cases were SCD cases.A total of 65 cases(57 males)out of 1656 SCD cases were sport-related.The age range of the 65 sport-related SCD cases was from 12 to 68 years old with a mean(35.92±14.23)years old.Only two of these cases were competitive athletes.The most common circumstances of the 65 sport-related SCD cases were heavy physical labour(46.15%)and running(30.77%).The three leading forensic diag-noses were the coronary atherosclerotic disease(CAD,28 cases),cardiomyopathy(CM,14 cases)and sudden unexplained death(7 cases).CM was the most common forensic diagno-sis in those?35 years old,while CAD was the most common one in those>35 years old.Left anterior descending in which atherosclerotic plaques was most commonly found was the principal artery branch associated with sport-related SCD.There was a statistically signifi-cant difference in the weight of hearts between the 65 sport-related SCD cases and 65 dis-eases-free accidental cases.This study highlights the need to attract public attention to sport-related SCD and to issue a prevention strategy to the public,and to make the SCD-related genetic sequencing a routine tool in both forensic pathological examination and clinic screening.
基金This work was supported by the National Key R&D Program of China[grant number 2017YFC0803502]the National Natural Science Foundation of China[grant number 81920108021].
文摘Autopsy is of great significance for elucidating the pathological changes,pathogenesis and cause of death of Coronavirus Disease 2019(COVID-19)and can provide a theoretical basis for scientific and accurate prevention and control of its outbreak.Based on related laws and regulations,such as the Law of the People's Republic of China on Prevention and Control of Infectious Diseases,clinical manifestations and epidemiological characteristics of COVID-19 and guidelines on the prevention and control of this epidemic,combined with the practical work of forensic pathology examinations,we developed the Guide to Forensic Pathology Practice for Death Cases Related to Coronavirus Disease 2019(COVID-19)(Trial Draft).This guide describes the background investigation of the death cases,autopsy room requirements,personal pre-vention and protections,external examinations,autopsy practices and auxiliary examinations,and thus offers a reference for forensic and pathological examination institutions and staff.
