Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and disco...Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.展开更多
OBJeCTIve：To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL： We retrieved relevant random and semi-random controlled trials th...OBJeCTIve：To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL： We retrieved relevant random and semi-random controlled trials that used theXingnao Kaiqiao needling method to treat ischemic stroke compared with various control treatments such as conventional drugs or other acupuncture therapies. Searched databases included China National Knowledge Infrastructure, Weipu Information Resources System, Wanfang Medical Data System, Chinese Biomedical Literature Database, Cochrane Library, and PubMed, from May 2006 to July 2014. SeLeCTION CRITeRIA： Two authors independently conducted literature screening, quality evaluation, and data extraction. The quality of articles was evaluated according to the Cochrane Reviewers’ Handbook 5.1, and the study was carried out using Cochrane system assessment methods. RevMan 5.2 was used for meta-analysis of the included studies. MAIN OUTCOMe MeASUReS： Mortality rate, recurrence rate, and disability rate were observed. ReSULTS：Nine randomized and semi-randomized controlled trials treating 931 cases of ischemic stroke were included in this review. Meta-analysis results showed that there were no sig-niifcant differences in mortality reduction （risk ratio （RR） = 0.58, 95% conifdence interval （CI）： 0.17–1.93,Z = 0.89,P = 0.37） or recurrence rate （RR = 0.55, 95%CI： 0.18–1.70,Z = 1.04,P = 0.30） of ischemic stroke patients between theXingnao Kaiqiao needling and control treatment groups. However, theXingnao Kaiqiao needling method had a tendency towards higher efifcacy in mor-tality reduction and recurrence rates. TheXingnao Kaiqiao needling method was signiifcantly better than that of the control treatment in reducing disability rate （RR = 0.51, 95%CI： 0.27–0.98, Z = 2.03,P 〈 0.05）. CONCLUSION：TheXingnao Kaiqiao needling method has a better effect than control treatment in reducing disability rate. The long-term effect ofXingnao Kaiqiao needling against ischemic stroke is better than that of control treatment. However, the limitations of this study limit the strength of the conclusions. Randomized controlled trials with a strict, reasonable design, and multi-center, large-scale samples and follow-up are necessary to draw conclusions aboutXingnao Kaiqiao needling.展开更多
This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the ext...This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the extended Kalman filter determined the amplitude dependency of natural frequency and damping factor, which are consistent with damage feature. Occurrence of partial uplifting in the transverse direction is suggested by the induced higher harmonics based on the wavelet analysis. Historical change of the amplitude dependent dynamic characteristics is also discussed based on the long-term monitoring data from microtremor level to strong motion level.展开更多
Air pollution caused by particulate matter has significantly improved in China in recent years since the implementation of a series of stringent clean-air regulations.However,surface ozone concentrations have increase...Air pollution caused by particulate matter has significantly improved in China in recent years since the implementation of a series of stringent clean-air regulations.However,surface ozone concentrations have increased,especially in developed city clusters,such as the Beijing–Tianjin–Hebei,Yangtze River Delta,Pearl River Delta,and Sichuan Basin regions.Due to the complexity and nonlinearity of the ozone formation,accurately locating major sources of ozone and its precursors is an important basis for the formulation of cost-effective pollution control strategies.In this paper,the authors systematically summarize the reported results and outcomes of the methods and main conclusions of ozone source apportionment(regions and categories)in China from the published literature,based on observation-based methods and emission-based methods,respectively.The authors aim to provide a comprehensive understanding of ozone pollution and reliable references for the formulation of air pollution prevention policies in China.展开更多
BACKGROUND Pneumonia is the main manifestation of coronavirus disease 2019(COVID-19)infection.Chest computed tomography is recommended for the initial evaluation of the disease;this technique can also be helpful to mo...BACKGROUND Pneumonia is the main manifestation of coronavirus disease 2019(COVID-19)infection.Chest computed tomography is recommended for the initial evaluation of the disease;this technique can also be helpful to monitor the disease progression and evaluate the therapeutic efficacy.AIM To review the currently available literature regarding the radiological follow-up of COVID-19-related lung alterations using the computed tomography scan,to describe the evidence about the dynamic evolution of COVID-19 pneumonia and verify the potential usefulness of the radiological follow-up.METHODS We used pertinent keywords on PubMed to select relevant studies;the articles we considered were published until October 30,2020.Through this selection,69 studies were identified,and 16 were finally included in the review.RESULTS Summarizing the included works’findings,we identified well-defined stages in the short follow-up time frame.A radiographic deterioration reaching a peak roughly within the first 2 wk;after the peak,an absorption process and repairing signs are observed.At later radiological follow-up,with the limitation of little evidence available,the lesions usually did not recover completely.CONCLUSION Following computed tomography scan evolution over time could help physicians better understand the clinical impact of COVID-19 pneumonia and manage the possible sequelae;a longer follow-up is advisable to verify the complete resolution or the presence of long-term damage.展开更多
This study maps the academic literature on Stock Price Forecasting with Long-Term Memory Artificial Neural Networks—RNA LSTM. The objective is to know if it is suitable for time series studies, especially for stock p...This study maps the academic literature on Stock Price Forecasting with Long-Term Memory Artificial Neural Networks—RNA LSTM. The objective is to know if it is suitable for time series studies, especially for stock price projection. Through bibliometric analysis and systematic literature review, it is observed that 333 authors wrote on the topic between 2018 and March 2022, and the journals Expert Systems with Applications, IEEE Access, Big Data Journal and Neural Computing and Applications, published the most relevant articles. Of the 99 articles published in this period, 43 are associated with Chinese institutions, the most cited being that of Kim and Won, who studies the volatility of returns and the market capitalization of South Korean stocks. The basis of 65% of the studies is the comparison between the RNN LSTM and other artificial neural networks. The daily closing price of shares is the most analyzed type of data, and the American (21%) and Chinese (20%) stock exchanges are the most studied. 57% of the studies include improvements to existing neural network models and 42% new projection models.展开更多
Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a m...Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage （assessed by SCSA, TUNEL, SCD, or Comet assay） and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles （with a total of 56 studies） including 16 IVF studies, 24 ICSI studies, and 16 mixed （IVF ＋ ICSI） studies. These studies measured DNA damage （by one of four assays： 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet） and included a total of 8068 treatment cycles （3734 IVF, 2282 ICSI, and 2052 mixed IVF ＋ ICSI）. The combined OR of 1.68 （95% Ch 1.49-1.89; P 〈 0.0001） indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF （16 estimates, OR = 1.65; 95% CI： 1.34-2.04; P 〈 0.0001）, ICSI （24 estimates, OR = 1.31; 95% Ch 1.08-1.59; P = 0.0068）, and mixed IVF ＋ ICSI studies （16 estimates, OR = 2.37; 95% Ch 1.89-2.97; P〈 0.0001） were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.展开更多
A long-term damage cumulative model for the duration of load effect of structural timber is proposed in this paper, which is economical in analysis as well as involving long-term hygrothermal effect. Based on the Mine...A long-term damage cumulative model for the duration of load effect of structural timber is proposed in this paper, which is economical in analysis as well as involving long-term hygrothermal effect. Based on the Miner linear damage cumulative theory, the cumulative damage model is applied to analyze the annual hygrothermal, daily cyclic thermal and daily cyclic relative humidity＇s effect on load-duration behavior and to calculate the sum of damage in one year. The results indicate that the annual and daily hygrothermal effect should be taken into consideration when calculating the damage accumulation, in which the influence levels from large to small are annual hygrothermal, daily relative humidity and daily thermal effect, Considering both annual and daily hygrothermal variations as external loads the long-term model is determined. Its application to service-life prediction of a historic timber structure verifies the feasibility and high-efficiency of the proposed approach.展开更多
文摘Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground Research Center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.
基金financially supported by grants from Hebei Province Engineering Talent Cultivation Project and Hebei Province Science and Technology Research and Development Projects,No.11276103D-35
文摘OBJeCTIve：To systematically evaluate the long-term effect and safety ofXingnao Kaiqiao nee-dling method in ischemic stroke treatment. DATA ReTRIevAL： We retrieved relevant random and semi-random controlled trials that used theXingnao Kaiqiao needling method to treat ischemic stroke compared with various control treatments such as conventional drugs or other acupuncture therapies. Searched databases included China National Knowledge Infrastructure, Weipu Information Resources System, Wanfang Medical Data System, Chinese Biomedical Literature Database, Cochrane Library, and PubMed, from May 2006 to July 2014. SeLeCTION CRITeRIA： Two authors independently conducted literature screening, quality evaluation, and data extraction. The quality of articles was evaluated according to the Cochrane Reviewers’ Handbook 5.1, and the study was carried out using Cochrane system assessment methods. RevMan 5.2 was used for meta-analysis of the included studies. MAIN OUTCOMe MeASUReS： Mortality rate, recurrence rate, and disability rate were observed. ReSULTS：Nine randomized and semi-randomized controlled trials treating 931 cases of ischemic stroke were included in this review. Meta-analysis results showed that there were no sig-niifcant differences in mortality reduction （risk ratio （RR） = 0.58, 95% conifdence interval （CI）： 0.17–1.93,Z = 0.89,P = 0.37） or recurrence rate （RR = 0.55, 95%CI： 0.18–1.70,Z = 1.04,P = 0.30） of ischemic stroke patients between theXingnao Kaiqiao needling and control treatment groups. However, theXingnao Kaiqiao needling method had a tendency towards higher efifcacy in mor-tality reduction and recurrence rates. TheXingnao Kaiqiao needling method was signiifcantly better than that of the control treatment in reducing disability rate （RR = 0.51, 95%CI： 0.27–0.98, Z = 2.03,P 〈 0.05）. CONCLUSION：TheXingnao Kaiqiao needling method has a better effect than control treatment in reducing disability rate. The long-term effect ofXingnao Kaiqiao needling against ischemic stroke is better than that of control treatment. However, the limitations of this study limit the strength of the conclusions. Randomized controlled trials with a strict, reasonable design, and multi-center, large-scale samples and follow-up are necessary to draw conclusions aboutXingnao Kaiqiao needling.
文摘This paper describes the dynamic characteristics of a damaged nine story building in Sendal during the 2011 Tohoku Earthquake. Dynamic hysteresis characteristic is investigated. The system identification using the extended Kalman filter determined the amplitude dependency of natural frequency and damping factor, which are consistent with damage feature. Occurrence of partial uplifting in the transverse direction is suggested by the induced higher harmonics based on the wavelet analysis. Historical change of the amplitude dependent dynamic characteristics is also discussed based on the long-term monitoring data from microtremor level to strong motion level.
基金supported by the National Natural Science Foundation of China grant number 41830109the National Key R&D Programs of China grant number2017YFB0503901。
文摘Air pollution caused by particulate matter has significantly improved in China in recent years since the implementation of a series of stringent clean-air regulations.However,surface ozone concentrations have increased,especially in developed city clusters,such as the Beijing–Tianjin–Hebei,Yangtze River Delta,Pearl River Delta,and Sichuan Basin regions.Due to the complexity and nonlinearity of the ozone formation,accurately locating major sources of ozone and its precursors is an important basis for the formulation of cost-effective pollution control strategies.In this paper,the authors systematically summarize the reported results and outcomes of the methods and main conclusions of ozone source apportionment(regions and categories)in China from the published literature,based on observation-based methods and emission-based methods,respectively.The authors aim to provide a comprehensive understanding of ozone pollution and reliable references for the formulation of air pollution prevention policies in China.
文摘BACKGROUND Pneumonia is the main manifestation of coronavirus disease 2019(COVID-19)infection.Chest computed tomography is recommended for the initial evaluation of the disease;this technique can also be helpful to monitor the disease progression and evaluate the therapeutic efficacy.AIM To review the currently available literature regarding the radiological follow-up of COVID-19-related lung alterations using the computed tomography scan,to describe the evidence about the dynamic evolution of COVID-19 pneumonia and verify the potential usefulness of the radiological follow-up.METHODS We used pertinent keywords on PubMed to select relevant studies;the articles we considered were published until October 30,2020.Through this selection,69 studies were identified,and 16 were finally included in the review.RESULTS Summarizing the included works’findings,we identified well-defined stages in the short follow-up time frame.A radiographic deterioration reaching a peak roughly within the first 2 wk;after the peak,an absorption process and repairing signs are observed.At later radiological follow-up,with the limitation of little evidence available,the lesions usually did not recover completely.CONCLUSION Following computed tomography scan evolution over time could help physicians better understand the clinical impact of COVID-19 pneumonia and manage the possible sequelae;a longer follow-up is advisable to verify the complete resolution or the presence of long-term damage.
文摘This study maps the academic literature on Stock Price Forecasting with Long-Term Memory Artificial Neural Networks—RNA LSTM. The objective is to know if it is suitable for time series studies, especially for stock price projection. Through bibliometric analysis and systematic literature review, it is observed that 333 authors wrote on the topic between 2018 and March 2022, and the journals Expert Systems with Applications, IEEE Access, Big Data Journal and Neural Computing and Applications, published the most relevant articles. Of the 99 articles published in this period, 43 are associated with Chinese institutions, the most cited being that of Kim and Won, who studies the volatility of returns and the market capitalization of South Korean stocks. The basis of 65% of the studies is the comparison between the RNN LSTM and other artificial neural networks. The daily closing price of shares is the most analyzed type of data, and the American (21%) and Chinese (20%) stock exchanges are the most studied. 57% of the studies include improvements to existing neural network models and 42% new projection models.
文摘Sperm DNA damage is prevalent among infertile men and is known to influence natural reproduction. However, the impact of sperm DNA damage on assisted reproduction outcomes remains controversial. Here, we conducted a meta-analysis of studies on sperm DNA damage （assessed by SCSA, TUNEL, SCD, or Comet assay） and clinical pregnancy after IVF and/or ICSI treatment from MEDLINE, EMBASE, and PUBMED database searches for this analysis. We identified 41 articles （with a total of 56 studies） including 16 IVF studies, 24 ICSI studies, and 16 mixed （IVF ＋ ICSI） studies. These studies measured DNA damage （by one of four assays： 23 SCSA, 18 TUNEL, 8 SCD, and 7 Comet） and included a total of 8068 treatment cycles （3734 IVF, 2282 ICSI, and 2052 mixed IVF ＋ ICSI）. The combined OR of 1.68 （95% Ch 1.49-1.89; P 〈 0.0001） indicates that sperm DNA damage affects clinical pregnancy following IVF and/or ICSI treatment. In addition, the combined OR estimates of IVF （16 estimates, OR = 1.65; 95% CI： 1.34-2.04; P 〈 0.0001）, ICSI （24 estimates, OR = 1.31; 95% Ch 1.08-1.59; P = 0.0068）, and mixed IVF ＋ ICSI studies （16 estimates, OR = 2.37; 95% Ch 1.89-2.97; P〈 0.0001） were also statistically significant. There is sufficient evidence in the existing literature suggesting that sperm DNA damage has a negative effect on clinical pregnancy following IVF and/or ICSI treatment.
基金Supported by the National Natural Science Foundation of China (50708083)
文摘A long-term damage cumulative model for the duration of load effect of structural timber is proposed in this paper, which is economical in analysis as well as involving long-term hygrothermal effect. Based on the Miner linear damage cumulative theory, the cumulative damage model is applied to analyze the annual hygrothermal, daily cyclic thermal and daily cyclic relative humidity＇s effect on load-duration behavior and to calculate the sum of damage in one year. The results indicate that the annual and daily hygrothermal effect should be taken into consideration when calculating the damage accumulation, in which the influence levels from large to small are annual hygrothermal, daily relative humidity and daily thermal effect, Considering both annual and daily hygrothermal variations as external loads the long-term model is determined. Its application to service-life prediction of a historic timber structure verifies the feasibility and high-efficiency of the proposed approach.
