The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fr...The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fracture lengths,and free surface depths is constructed to investigate the cracking and deformation behavior of overhanging rocks.Laboratory tests and deformation field monitoring using the digital image correlation(DIC)method are performed on these specimens to reproduce the destabilization and failure process of overhanging rock under external loading.The influence of peak load is found to be the most sensitive to the fracture length,followed by the free surface depth,and to be the least sensitive to the fracture angle.The DIC-based strain fields reveal that the fracture angle and free surface depth significantly alter the crack propagation paths,whereas the influence of the fracture length is weaker.These parameters also affect the crack initiation time.The relative displacement evolution characteristics indicate that fracture angle,fracture length,and free surface depth affect the shape and size of the rotating block,the rotation center,and the rotation pivot point and degree,respectively.The grayscale characteristic evolution trends are similar for all examined overhanging rock specimens.The evolution of the grayscale indices based on DIC can be divided into high-frequency oscillation,smooth decline(or smooth downward concavity),and stable development stages.Furthermore,the multistage properties of the indices can be used to identify the fracture state of overhanging rocks,providing a theoretical basis for graded early warning of rockfall disasters.展开更多
Low frequency vibrations induced by underground railways have attracted increasing attention in recent years. To obtain the characteristics of low frequency vibrations and the low frequency performance of a floating s...Low frequency vibrations induced by underground railways have attracted increasing attention in recent years. To obtain the characteristics of low frequency vibrations and the low frequency performance of a floating slab track (FST), low frequency vibration tests on an FST in an underground laboratory at Beijing Jiaotong University were carried out. The FST and an unbalanced shaker SBZ30 for dynamic simulation were designed for use in low frequency vibration experiments. Vibration measurements were performed on the bogie of the unbalanced shaker, the rail, the slab, the tunnel invert, the tunnel wall, the tunnel apex, and on the ground surface at distances varying from 0 to 80 m from the track. Measurements were also made on several floors of an adjacent building. Detailed results of low frequency vibration tests were reported. The attenuation of low frequency vibrations with the distance from the track was presented, as well as the responses of different floors of the building. The experimental results could be regarded as a reference for developing methods to control low frequency vibrations and for adopting countermeasures.展开更多
In order to study the engineering behaviors of reinforced gabion retaining wall,laboratory model test was carried out.Cyclic load and unload of five levels(0-50,0-100,0-50,0-200 and 0-250 kPa) were imposed.Vertical ea...In order to study the engineering behaviors of reinforced gabion retaining wall,laboratory model test was carried out.Cyclic load and unload of five levels(0-50,0-100,0-50,0-200 and 0-250 kPa) were imposed.Vertical earth pressure,lateral earth pressure,deformation behaviors of reinforcements,potential failure surface and deformation behaviors of wall face were studied.Results show that vertical earth pressure is less than theoretical value,the ratio of vertical earth pressure to theoretical value increases nearly linearly with increasing load,and the correlation coefficient of regression equation is 0.92 for the second layer and 0.79 for the fifth layer.The distribution of lateral earth pressure along the wall back is nonlinear and it is less than theoretical value especially when the load imposed at the top of retaining wall is large.Therefore,reinforced gabion retaining wall will be in great safety when current method is adopted.The deformation behaviors of reinforcements both in the third layer and the fifth layer are single-peak distributions,and the position of the maximum strain is behind that determined by 0.3H(Here H refers to the height of retaining wall) method or Rankine theory.Lateral deformation of wall face increases with increasing load,and the largest lateral deformation occurs in the fourth layer,which lead to a bulging in the middle of wall face.展开更多
The deformation of sea coast or sandy deposits caused by earthquakes can lead to catastrophic damages to various port structures. The volumetric deformation is mainly induced by densification of sand during the dissip...The deformation of sea coast or sandy deposits caused by earthquakes can lead to catastrophic damages to various port structures. The volumetric deformation is mainly induced by densification of sand during the dissipation of excess pore water pressure created by cyclic loading. Based on laboratory test, the reconsolidation volumetric characteristics of saturated sea sand are investigated. The experiments are conducted with a newly developed multi functional triaxial test equipment. Two types of dynamic loads are applied to the samples to clarify different kinds of affecting factors. It is found that the reconsolidation volumetric strain is correlated not only to the excess pore water pressure and the maximum shear strain during the dynamic loading, but also to the effective confining pressure. A new formula is put forward to calculate the volumetric strain during reconssolidation.展开更多
Acute respiratory tract infection</span><span style="font-family:""><span style="font-family:Verdana;"> (ARTI) in children is the most common infectious disease in childhood,...Acute respiratory tract infection</span><span style="font-family:""><span style="font-family:Verdana;"> (ARTI) in children is the most common infectious disease in childhood, and its pathogens include viruses, bacteria and fungi, mycoplasma, chlamydia and rickettsia. In recent years, with the continuous development of pathogen detection methods, the diagnosis and treatment of acute respiratory infections has received more and more clinical attention. The clinical diagnosis and treatment characteristics of acute respira</span><span style="font-family:Verdana;">tory infections in children and the research of clinical laboratory detection </span><span style="font-family:Verdana;">methods have also been continuously developed. The author collected refer</span><span style="font-family:Verdana;">ences to review the clinical features and new developments in laboratory</span><span style="font-family:Verdana;"> testing of acute respiratory tract infection in children.展开更多
A series of polyester, cotton, and polyester/cotton blend fabrics were evaluated in a subjective wear. Subjective trial data were correlated with the results of in-house laboratory tests with the regression methods. E...A series of polyester, cotton, and polyester/cotton blend fabrics were evaluated in a subjective wear. Subjective trial data were correlated with the results of in-house laboratory tests with the regression methods. Experimental results indicate that clothing-comfort assessment by human perception provides a sound basis for comparison of apparel garments under combined microclimates and human-activity levels of展开更多
900 abusers were tested for the presence of drug abuse and coronavirus disease.In the early stage,the throat and noise samples of these patients were examined by polymerase chain reaction(PCR).The mean age of the stud...900 abusers were tested for the presence of drug abuse and coronavirus disease.In the early stage,the throat and noise samples of these patients were examined by polymerase chain reaction(PCR).The mean age of the study group is 42±23.Hematological and serological examinations were performed on 131 patients.All data were analyzed by t-test and one-way analysis of variance(ANOVA).Therefore,P<0.05 is considered as the significance of the test results.The results showed that 131 patients in the study group had positive results of PCR tests and nearby they had Covid-19.Approximately 90%of patients with coronavirus disease showed positive serological tests and lymphopenic condition.All of urine or blood samples in the 131 patients were positive for the presence of abuse drugs.C-reactive protein(CRP)is one of important serologic test that detected on these patients.This study showed the importance of molecular genetics test such as PCR and also hematology and serology tests in distinguish of coronavirus diseases.展开更多
Objective:Perform a literary review of the interference in the results of biochemical laboratory tests caused by antihypertensive drugs.Methods:This is a review of the scientific literature with descriptive research p...Objective:Perform a literary review of the interference in the results of biochemical laboratory tests caused by antihypertensive drugs.Methods:This is a review of the scientific literature with descriptive research performed according to the PRISMA model using the databases PUBMED,SCIELO,MEDLINE,LILACS,and searches of Brazilian Ministry of Health and Federal Pharmacy Council publications,reagent kits and package inserts approved by ANVISA.Literature and papers in Portuguese and English were selected,prioritizing the years 2010 to 2020.Results:The diuretic class of antihypertensive drugs causes decreases glucose tolerance,thus resulting in an increase in triglycerides.In long-term use,the drug captopril can increase serum levels of potassium,creatine kinase and decreases blood sodium.Methyldopa causes an increase in AST levels.Propranolol is associated with an increase in triglyceride levels and a decrease in HDL and glucose levels.The constant use of losartan results in an increase in HDL,a decrease in uric acid levels and a slight and transient increase in transaminases.In the Gold Analisa,Bioclin and Labtest reagent kits,most of the alterations occur due to the increase in levels of serum biomarkers according to the class of the antihypertensive drug.Conclusions:Biochemical alterations in serum can result in false-positive or false-negative reports,since it can be observed that most of the dosages caused increases due to the physiological effect of the drugs.The antihypertensive drugs that showed the highest incidence of interference were captopril,atenolol,losartan and propranolol.展开更多
In this study, five hundred urine samples and five hundred blood samples of abusers were examined for the presence of alkaloid substances and abuse drugs in urines and bloods. These numbers of blood and urine samples ...In this study, five hundred urine samples and five hundred blood samples of abusers were examined for the presence of alkaloid substances and abuse drugs in urines and bloods. These numbers of blood and urine samples of addicts in clinics of welfare organization, during detoxification treatment or maintenance treatment were screened for abuse drugs presence. The all of samples were tested through as a view of clinical laboratory methods. Age ranges of female patients were 35 ~ 15 and age range of males patients were 45 ~ 15. All patients filled questionnaire and satisfy forms too. First, all fresh urine and blood samples were examined to confirm presence drugs abuses, depend on their addiction and treatment, so all samples were confirmed by two tests. Then they were examined to other clinical laboratory tests. All data were analyzed by t-test and were Anova one way and two ways of Anova Turkey, and p 〈 0.05 was considered significant. The p-value of this study was p = 0.0001. The results of this study were showed that 4% of abusers had mild increase in hematocrite level and 2% of narcotic drugs abusers had mild lower level of blood sugars than normal range and 4% of participants had increase liver enzymes such ALT （alanine transferase）, AST （aspartat transferase）, ALP （alkaline phosphatease） and 1% of them had renal failure. Although blood level BUN （blood urea nitrogen） and creatinin were examined to evaluation of their renal failure .The results in Tabriz/Iran undrevision of welfare organization clinics were approximately showed that positive results of addiction are in each of urine and blood samples. Because some of abusers directly consumed full long time agonist or partial agonists＇ drugs such as methadone and buprenorphine for their maintenance therapy in clinics. Also doing test on blood samples has high importance in distinguishing and confirmation of drugs abuse in samples. Also in this study we conclude that among all drug analytical methods the cheapest and easiest test to screening opioids and other abuse drugs in urine and blood samples is strip test for rapid diagnosis, also tests on blood samples have high importance as a view point of accuracy to distinguishing of drugs abuse, and serum levels of some other parameters showed all abusers patients situation such as liver and renal dysfimction through clinical laboratory tests.展开更多
The characteristics of USB data acquisition system NI cDAQ and its control software LabVIEW are briefed.The methods for controlling GDS pressure and volume controller by LabVIEW through serial port communication are p...The characteristics of USB data acquisition system NI cDAQ and its control software LabVIEW are briefed.The methods for controlling GDS pressure and volume controller by LabVIEW through serial port communication are presented.A practical data sharing method among geotechnical testing systems is illustrated.As an application case on a modified conventional soil triaxial testing system,the automatic triaxial testing system is designed by LabVIEW.Based on the control panel,the cell pressure and back pressure can be controlled independently and the testing data can be recorded automatically.展开更多
There is a general consensus in re-interpreting the so-called liver function tests in the light of novel discoveries. At the same time, recent evidence favours the use of different laboratory data to assess liver dama...There is a general consensus in re-interpreting the so-called liver function tests in the light of novel discoveries. At the same time, recent evidence favours the use of different laboratory data to assess liver damage, fibrosis or regenerative process, but this point is not always shared. Actually, balancing the need for diagnosis, prognostic evaluation and therapy response of liver disease with a good cost/benefit ratio is very difficult. New tests are probably not needed but the aim should be for better utilization of existing tests to contain the increasing cost of health care.展开更多
Acute respiratory infection in children (ARTI) is the most common childhood infectious disease, and its pathogens include bacteria, fungi, viruses, chlamydia, mycoplasma and rickettsia. In recent years, with the conti...Acute respiratory infection in children (ARTI) is the most common childhood infectious disease, and its pathogens include bacteria, fungi, viruses, chlamydia, mycoplasma and rickettsia. In recent years, with the continuous development of pathogen detection methods, the diagnosis and treatment of acute respiratory infections has received more and more attention from clinicians. The clinical diagnosis and treatment of acute respiratory infections in children and the research of laboratory detection methods have also been continuously developed. The manuscript presents a review of progress in the clinical diagnosis, treatment and laboratory testing of acute respiratory infections in children by collecting references.展开更多
Underground mine pillars provide natural stability to the mine area,allowing safe operations for workers and machinery.Extensive prior research has been conducted to understand pillar failure mechanics and design safe...Underground mine pillars provide natural stability to the mine area,allowing safe operations for workers and machinery.Extensive prior research has been conducted to understand pillar failure mechanics and design safe pillar layouts.However,limited studies(mostly based on empirical field observation and small-scale laboratory tests)have considered pillar-support interactions under monotonic loading conditions for the design of pillar-support systems.This study used a series of large-scale laboratory compression tests on porous limestone blocks to analyze rock and support behavior at a sufficiently large scale(specimens with edge length of 0.5 m)for incorporation of actual support elements,with consideration of different w/h ratios.Both unsupported and supported(grouted rebar rockbolt and wire mesh)tests were conducted,and the surface deformations of the specimens were monitored using three-dimensional(3D)digital image correlation(DIC).Rockbolts instrumented with distributed fiber optic strain sensors were used to study rockbolt strain distribution,load mobilization,and localized deformation at different w/h ratios.Both axial and bending strains were observed in the rockbolts,which became more prominent in the post-peak region of the stress-strain curve.展开更多
The Norwegian Public Roads Administration(NPRA) is planning for an upgrade of the E39 highway route at the westcoast of Norway. Fixed links shall replace ferries at seven fjord crossings. Wide spans and large depths a...The Norwegian Public Roads Administration(NPRA) is planning for an upgrade of the E39 highway route at the westcoast of Norway. Fixed links shall replace ferries at seven fjord crossings. Wide spans and large depths at the crossings combined with challenging subsea topography and environmental loads call for an extension of existing practice. A variety of bridge concepts are evaluated in the feasibility study. The structures will experience significant loads from deadweight, traffic and environment. Anchoring of these forces is thus one of the challenges met in the project. Large-size subsea rock anchors are considered a viable alternative. These can be used for anchoring of floating structures but also with the purpose of increasing capacity of fixed structures. This paper presents first a thorough study of factors affecting rock anchor bond capacity. Laboratory testing of rock anchors subjected to cyclic loading is thereafter presented. Finally, the paper presents a model predicting the capacity of a rock anchor segment, in terms of a ribbed bar, subjected to a cyclic load history. The research assumes a failure mode occurring in the interface between the rock anchor and the surrounding grout. The constitutive behavior of the bonding interface is investigated for anchors subjected to cyclic one-way tensile loads. The model utilizes the static bond capacity curve as a basis, defining the ultimate bond sbuand the slip s1 at τ. A limited number of input parameters are required to apply the model. The model defines the bond-slip behavior with the belonging rock anchor capacity depending on the cyclic load level(τcy/τ), the cyclic load ratio(R= τcy/τcy), and the number of load cycles(N). The constitutive model is intended to model short anchor lengths representing an incremental length of a complete rock anchor.展开更多
In order to improve the effectiveness of shale gas stimulated reservoir volume(SRV),it is necessary to evaluate and study the permeability of different types of induced fractures in shale and its influential factors.I...In order to improve the effectiveness of shale gas stimulated reservoir volume(SRV),it is necessary to evaluate and study the permeability of different types of induced fractures in shale and its influential factors.In this paper,the mineral composition characteristics,reservoir pore and fracture characteristics of shale were investigated,and the permeability of three types of induced fractures in shale(i.e.,in-situ closed type,shear self-propped type and single-layer propped type)was tested.Besides,the effects of fracture type,fracture surface roughness,carbonate content,shale bedding and confining pressure on the permeability of induced fractures in shale reservoirs were studied systematically.The following research results were obtained.First,the permeabilityepressure relationship of in-situ closed fracture is in accordance with the Walsh theory.The permeability decreases with the increase of confining pressure and it is in the range of 0.13e16.75 mD.In-situ closed fracture plays the same role in increasing the productivity of shale gas reservoirs with or without proppant filling or dislocation.Second,compared with in-situ closed fracture permeability,the shear self-propped fracture permeability is 1e2 orders of magnitude(7.53e88.48 mD)higher,and single-layer propped fracture permeability is 2e3 orders of magnitude(9.98e771.82 mD)higher.Third,the larger the fracture surface roughness,the higher the fracture permeability.And there is a better positive correlation between the fractal dimension and the fracture permeability.Fourth,the permeabilityepressure relationship of shear self-propped fracture and single-layer propped fracture is,to some extent,deviated from the Walsh theory,which reflects the influence of self-propped point crushing,proppant embedding and crushing.In conclusion,the experimental results can be used as the reference for the selection of shale fracturing technologies and the optimization of parameters.展开更多
Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from ...Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.展开更多
When the pore pressure in a porous rock changes, stress arching will occur within the rock and the surrounding region. Stress arching ratio is defined as the total stress changes in the porous rock to the pore pressur...When the pore pressure in a porous rock changes, stress arching will occur within the rock and the surrounding region. Stress arching ratio is defined as the total stress changes in the porous rock to the pore pressure change in the region. The region may have the same or different elastic moduli with the surrounding rock, which is usually referred to as inclusion or inhomogeneity. Stress arching is responsible for many geomechanical problems encountered during production or injection; in addition, it is a crucial parameter in stress estimation during field development. This paper aims to present laboratory measurements of vertical stress arching ratio in a material surrounding the inclusion(inhomogeneity).To the authors’ knowledge, few laboratory experiments have been reported on direct measurement of stress arching. The inclusion is a cylindrical sandstone(44 mm in diameter and 50 mm in height)embedded in a larger cylindrical sandstone(150 mm in diameter and 154 mm in height), both of which are made synthetically. These two parts are separated and sealed by a internal polyurethane sleeve.Vertical stress changes are recorded by a mini hydraulic sensor embedded in surrounding rock. Laboratory results are compared to those obtained by numerical models. These models are checked with analytical formulations. The results of numerical models show a good agreement with laboratory data.The numerical results also indicate that the sensor response is affected by elastic properties of the internal sleeve. According to the sensitivity analysis performed, in the absence of the internal sleeve,properties of the inclusion have significant effects on the surrounding stress arching induced.展开更多
Objective:To summarize the follow-up results of laboratory examination,echocardiographic and chest CT of patients with COVID-19 at the time of 2 years after discharge in Chengdu.Methods:A total of 29 COVID-19 survivor...Objective:To summarize the follow-up results of laboratory examination,echocardiographic and chest CT of patients with COVID-19 at the time of 2 years after discharge in Chengdu.Methods:A total of 29 COVID-19 survivors who have participated in the 1-year follow-up and 2-year follow-up at Public Health Clinical Center of Chengdu were included in our study.Their blood laboratory tests,echocardiography and chest CT results were analyzed in order to evaluate the long-term recovery of COVID-19 survivors.Results:The most common abnormal laboratory test results at the 2-year follow-up were increased serum fibronectin(21 cases,72.4%)and decreased NK cell counts(19 cases,65.5%).Compared with laboratory test results at the 1-year follow-up,platelet count,hydroxybutyrate dehydrogenase and creatine kinase isoenzyme were decreased(all P<0.05),while serum fibrinogen,triglyceride,insulin and non-specific immunoglobulin A were increased(all P<0.05).Serum specific total SARS-CoV-2 antibody amount in COVID-19 survivors at half a year after COVID-19 vaccine was significantly higher than that before vaccination.More than half of patients(55.2%)had normal echocardiography results at the 2-year follow-up,the main abnormal results of them were valve regurgitation(7 cases,24.1%)and reduced left ventricular diastolic function(9 cases,31.0%).Compared with 1-year follow-up,7 patients had fewer abnormal cardiac ultrasound results.28 cases underwent chest CT at the 2-year follow-up,the mainly abnormal results were ground glass shadow(17.9%),pulmonary nodules(diameter<6mm)(32.1%)and scattered cable shadow(39.3%).71.4%(20/28)of them had no significant change between the two chest CT results.Conclusion:The mainly abnormal blood laboratory indicators in COVID-19 survivors at 2-year follow-up after discharge were increased serum fibronectin and decreased NK cell counts.Although echocardiography and chest CT results were no significant change between 1-year follow-up and 2-year follow-up among COVID-19 survivors,there were still some patients whose abnormal results were decreasing.Serum specific total SARS-CoV-2 antibody amount in COVID-19 survivors at half a year after COVID-19 vaccine was still significantly higher than that before vaccination,but the amount of specific antibody had a downward trend with time.展开更多
A complex Laboratory Developed Test(LDT)is a clinical test developed within a single laboratory.It is typically configured from many fea-ture constraints from clinical repositories,which are part of the existing Lab-o...A complex Laboratory Developed Test(LDT)is a clinical test developed within a single laboratory.It is typically configured from many fea-ture constraints from clinical repositories,which are part of the existing Lab-oratory Information Management System(LIMS).Although these clinical repositories are automated,support for managing patient information with test results of an LDT is also integrated within the existing LIMS.Still,the support to configure LDTs design needs to be made available even in standard LIMS packages.The manual configuration of LDTs is a complex process and can generate configuration inconsistencies because many constraints between features can remain unsatisfied.It is a risky process and can lead patients to undergo unnecessary treatments.We proposed an optimized solution(opt-LDT)based on Genetic Algorithms to automate the configuration and resolve the inconsistencies in LDTs.Opt-LDT encodes LDT configuration as an optimization problem and generates a consistent configuration that satisfies the constraints of the features.We tested and validated opt-LDT for a local secondary care hospital in a real healthcare environment.Our results,averaged over ten runs,show that opt-LDT resolves 90%of inconsistencies while taking between 6 and 6.5 s for each configuration.Moreover,positive feedback based on a subjective questionnaire from clinicians regarding the performance,acceptability,and efficiency of opt-LDT motivates us to present our results for regulatory approval.展开更多
The compelling case report by Xie et al,published in a renowned medical journal,is an excellent example of meticulous clinical evaluation,comprehensive labo-ratory testing,advanced imaging,and genetic analysis.The aut...The compelling case report by Xie et al,published in a renowned medical journal,is an excellent example of meticulous clinical evaluation,comprehensive labo-ratory testing,advanced imaging,and genetic analysis.The authors identified novel compound heterozygous mutations in the hemojuvelin gene of a patient diagnosed with juvenile hemochromatosis.They suggested that long-term,strategic phlebotomy might offer a novel therapeutic strategy for severe juvenile hemochromatosis,challenging the traditional treatment paradigms.展开更多
基金supported by the China National Natural Science Foundation(Grant No.42362034)the Applied Basic Research Foundation of Yunnan Province,China(Grant No.202401AS070068).
文摘The destabilization of overhanging rock is a dangerous geological problem.In this study,a generalized model of typical overhanging cliffs from the Three Gorges Reservoir area in China with different fracture angles,fracture lengths,and free surface depths is constructed to investigate the cracking and deformation behavior of overhanging rocks.Laboratory tests and deformation field monitoring using the digital image correlation(DIC)method are performed on these specimens to reproduce the destabilization and failure process of overhanging rock under external loading.The influence of peak load is found to be the most sensitive to the fracture length,followed by the free surface depth,and to be the least sensitive to the fracture angle.The DIC-based strain fields reveal that the fracture angle and free surface depth significantly alter the crack propagation paths,whereas the influence of the fracture length is weaker.These parameters also affect the crack initiation time.The relative displacement evolution characteristics indicate that fracture angle,fracture length,and free surface depth affect the shape and size of the rotating block,the rotation center,and the rotation pivot point and degree,respectively.The grayscale characteristic evolution trends are similar for all examined overhanging rock specimens.The evolution of the grayscale indices based on DIC can be divided into high-frequency oscillation,smooth decline(or smooth downward concavity),and stable development stages.Furthermore,the multistage properties of the indices can be used to identify the fracture state of overhanging rocks,providing a theoretical basis for graded early warning of rockfall disasters.
基金Project supported by the National Natural Science Foundation of China (No. 51008017)the Fundamental Research Funds for the Central Universities of China (Nos. 2009JBM074 and 2009JBM075)
文摘Low frequency vibrations induced by underground railways have attracted increasing attention in recent years. To obtain the characteristics of low frequency vibrations and the low frequency performance of a floating slab track (FST), low frequency vibration tests on an FST in an underground laboratory at Beijing Jiaotong University were carried out. The FST and an unbalanced shaker SBZ30 for dynamic simulation were designed for use in low frequency vibration experiments. Vibration measurements were performed on the bogie of the unbalanced shaker, the rail, the slab, the tunnel invert, the tunnel wall, the tunnel apex, and on the ground surface at distances varying from 0 to 80 m from the track. Measurements were also made on several floors of an adjacent building. Detailed results of low frequency vibration tests were reported. The attenuation of low frequency vibrations with the distance from the track was presented, as well as the responses of different floors of the building. The experimental results could be regarded as a reference for developing methods to control low frequency vibrations and for adopting countermeasures.
基金Project(50778180) supported by the National Natural Science Foundation of ChinaProject(CX2010B049) supported by Hunan Provincial Innovation Foundation for Postgraduate,China
文摘In order to study the engineering behaviors of reinforced gabion retaining wall,laboratory model test was carried out.Cyclic load and unload of five levels(0-50,0-100,0-50,0-200 and 0-250 kPa) were imposed.Vertical earth pressure,lateral earth pressure,deformation behaviors of reinforcements,potential failure surface and deformation behaviors of wall face were studied.Results show that vertical earth pressure is less than theoretical value,the ratio of vertical earth pressure to theoretical value increases nearly linearly with increasing load,and the correlation coefficient of regression equation is 0.92 for the second layer and 0.79 for the fifth layer.The distribution of lateral earth pressure along the wall back is nonlinear and it is less than theoretical value especially when the load imposed at the top of retaining wall is large.Therefore,reinforced gabion retaining wall will be in great safety when current method is adopted.The deformation behaviors of reinforcements both in the third layer and the fifth layer are single-peak distributions,and the position of the maximum strain is behind that determined by 0.3H(Here H refers to the height of retaining wall) method or Rankine theory.Lateral deformation of wall face increases with increasing load,and the largest lateral deformation occurs in the fourth layer,which lead to a bulging in the middle of wall face.
文摘The deformation of sea coast or sandy deposits caused by earthquakes can lead to catastrophic damages to various port structures. The volumetric deformation is mainly induced by densification of sand during the dissipation of excess pore water pressure created by cyclic loading. Based on laboratory test, the reconsolidation volumetric characteristics of saturated sea sand are investigated. The experiments are conducted with a newly developed multi functional triaxial test equipment. Two types of dynamic loads are applied to the samples to clarify different kinds of affecting factors. It is found that the reconsolidation volumetric strain is correlated not only to the excess pore water pressure and the maximum shear strain during the dynamic loading, but also to the effective confining pressure. A new formula is put forward to calculate the volumetric strain during reconssolidation.
文摘Acute respiratory tract infection</span><span style="font-family:""><span style="font-family:Verdana;"> (ARTI) in children is the most common infectious disease in childhood, and its pathogens include viruses, bacteria and fungi, mycoplasma, chlamydia and rickettsia. In recent years, with the continuous development of pathogen detection methods, the diagnosis and treatment of acute respiratory infections has received more and more clinical attention. The clinical diagnosis and treatment characteristics of acute respira</span><span style="font-family:Verdana;">tory infections in children and the research of clinical laboratory detection </span><span style="font-family:Verdana;">methods have also been continuously developed. The author collected refer</span><span style="font-family:Verdana;">ences to review the clinical features and new developments in laboratory</span><span style="font-family:Verdana;"> testing of acute respiratory tract infection in children.
文摘A series of polyester, cotton, and polyester/cotton blend fabrics were evaluated in a subjective wear. Subjective trial data were correlated with the results of in-house laboratory tests with the regression methods. Experimental results indicate that clothing-comfort assessment by human perception provides a sound basis for comparison of apparel garments under combined microclimates and human-activity levels of
文摘900 abusers were tested for the presence of drug abuse and coronavirus disease.In the early stage,the throat and noise samples of these patients were examined by polymerase chain reaction(PCR).The mean age of the study group is 42±23.Hematological and serological examinations were performed on 131 patients.All data were analyzed by t-test and one-way analysis of variance(ANOVA).Therefore,P<0.05 is considered as the significance of the test results.The results showed that 131 patients in the study group had positive results of PCR tests and nearby they had Covid-19.Approximately 90%of patients with coronavirus disease showed positive serological tests and lymphopenic condition.All of urine or blood samples in the 131 patients were positive for the presence of abuse drugs.C-reactive protein(CRP)is one of important serologic test that detected on these patients.This study showed the importance of molecular genetics test such as PCR and also hematology and serology tests in distinguish of coronavirus diseases.
文摘Objective:Perform a literary review of the interference in the results of biochemical laboratory tests caused by antihypertensive drugs.Methods:This is a review of the scientific literature with descriptive research performed according to the PRISMA model using the databases PUBMED,SCIELO,MEDLINE,LILACS,and searches of Brazilian Ministry of Health and Federal Pharmacy Council publications,reagent kits and package inserts approved by ANVISA.Literature and papers in Portuguese and English were selected,prioritizing the years 2010 to 2020.Results:The diuretic class of antihypertensive drugs causes decreases glucose tolerance,thus resulting in an increase in triglycerides.In long-term use,the drug captopril can increase serum levels of potassium,creatine kinase and decreases blood sodium.Methyldopa causes an increase in AST levels.Propranolol is associated with an increase in triglyceride levels and a decrease in HDL and glucose levels.The constant use of losartan results in an increase in HDL,a decrease in uric acid levels and a slight and transient increase in transaminases.In the Gold Analisa,Bioclin and Labtest reagent kits,most of the alterations occur due to the increase in levels of serum biomarkers according to the class of the antihypertensive drug.Conclusions:Biochemical alterations in serum can result in false-positive or false-negative reports,since it can be observed that most of the dosages caused increases due to the physiological effect of the drugs.The antihypertensive drugs that showed the highest incidence of interference were captopril,atenolol,losartan and propranolol.
文摘In this study, five hundred urine samples and five hundred blood samples of abusers were examined for the presence of alkaloid substances and abuse drugs in urines and bloods. These numbers of blood and urine samples of addicts in clinics of welfare organization, during detoxification treatment or maintenance treatment were screened for abuse drugs presence. The all of samples were tested through as a view of clinical laboratory methods. Age ranges of female patients were 35 ~ 15 and age range of males patients were 45 ~ 15. All patients filled questionnaire and satisfy forms too. First, all fresh urine and blood samples were examined to confirm presence drugs abuses, depend on their addiction and treatment, so all samples were confirmed by two tests. Then they were examined to other clinical laboratory tests. All data were analyzed by t-test and were Anova one way and two ways of Anova Turkey, and p 〈 0.05 was considered significant. The p-value of this study was p = 0.0001. The results of this study were showed that 4% of abusers had mild increase in hematocrite level and 2% of narcotic drugs abusers had mild lower level of blood sugars than normal range and 4% of participants had increase liver enzymes such ALT （alanine transferase）, AST （aspartat transferase）, ALP （alkaline phosphatease） and 1% of them had renal failure. Although blood level BUN （blood urea nitrogen） and creatinin were examined to evaluation of their renal failure .The results in Tabriz/Iran undrevision of welfare organization clinics were approximately showed that positive results of addiction are in each of urine and blood samples. Because some of abusers directly consumed full long time agonist or partial agonists＇ drugs such as methadone and buprenorphine for their maintenance therapy in clinics. Also doing test on blood samples has high importance in distinguishing and confirmation of drugs abuse in samples. Also in this study we conclude that among all drug analytical methods the cheapest and easiest test to screening opioids and other abuse drugs in urine and blood samples is strip test for rapid diagnosis, also tests on blood samples have high importance as a view point of accuracy to distinguishing of drugs abuse, and serum levels of some other parameters showed all abusers patients situation such as liver and renal dysfimction through clinical laboratory tests.
基金Laboratory and numerical modelling of unsaturated flow in fractured soil and rock(50609012)Fund Proposer:ZHANG Hua.
文摘The characteristics of USB data acquisition system NI cDAQ and its control software LabVIEW are briefed.The methods for controlling GDS pressure and volume controller by LabVIEW through serial port communication are presented.A practical data sharing method among geotechnical testing systems is illustrated.As an application case on a modified conventional soil triaxial testing system,the automatic triaxial testing system is designed by LabVIEW.Based on the control panel,the cell pressure and back pressure can be controlled independently and the testing data can be recorded automatically.
文摘There is a general consensus in re-interpreting the so-called liver function tests in the light of novel discoveries. At the same time, recent evidence favours the use of different laboratory data to assess liver damage, fibrosis or regenerative process, but this point is not always shared. Actually, balancing the need for diagnosis, prognostic evaluation and therapy response of liver disease with a good cost/benefit ratio is very difficult. New tests are probably not needed but the aim should be for better utilization of existing tests to contain the increasing cost of health care.
文摘Acute respiratory infection in children (ARTI) is the most common childhood infectious disease, and its pathogens include bacteria, fungi, viruses, chlamydia, mycoplasma and rickettsia. In recent years, with the continuous development of pathogen detection methods, the diagnosis and treatment of acute respiratory infections has received more and more attention from clinicians. The clinical diagnosis and treatment of acute respiratory infections in children and the research of laboratory detection methods have also been continuously developed. The manuscript presents a review of progress in the clinical diagnosis, treatment and laboratory testing of acute respiratory infections in children by collecting references.
基金the funding support from Alpha Foundation for the Improvement of Mine Safety and Health Inc.(ALPHAFOUNDATION,Grant No.AFC820-52)。
文摘Underground mine pillars provide natural stability to the mine area,allowing safe operations for workers and machinery.Extensive prior research has been conducted to understand pillar failure mechanics and design safe pillar layouts.However,limited studies(mostly based on empirical field observation and small-scale laboratory tests)have considered pillar-support interactions under monotonic loading conditions for the design of pillar-support systems.This study used a series of large-scale laboratory compression tests on porous limestone blocks to analyze rock and support behavior at a sufficiently large scale(specimens with edge length of 0.5 m)for incorporation of actual support elements,with consideration of different w/h ratios.Both unsupported and supported(grouted rebar rockbolt and wire mesh)tests were conducted,and the surface deformations of the specimens were monitored using three-dimensional(3D)digital image correlation(DIC).Rockbolts instrumented with distributed fiber optic strain sensors were used to study rockbolt strain distribution,load mobilization,and localized deformation at different w/h ratios.Both axial and bending strains were observed in the rockbolts,which became more prominent in the post-peak region of the stress-strain curve.
基金sponsored by the Norwegian Public Roads Administration(NPRA)
文摘The Norwegian Public Roads Administration(NPRA) is planning for an upgrade of the E39 highway route at the westcoast of Norway. Fixed links shall replace ferries at seven fjord crossings. Wide spans and large depths at the crossings combined with challenging subsea topography and environmental loads call for an extension of existing practice. A variety of bridge concepts are evaluated in the feasibility study. The structures will experience significant loads from deadweight, traffic and environment. Anchoring of these forces is thus one of the challenges met in the project. Large-size subsea rock anchors are considered a viable alternative. These can be used for anchoring of floating structures but also with the purpose of increasing capacity of fixed structures. This paper presents first a thorough study of factors affecting rock anchor bond capacity. Laboratory testing of rock anchors subjected to cyclic loading is thereafter presented. Finally, the paper presents a model predicting the capacity of a rock anchor segment, in terms of a ribbed bar, subjected to a cyclic load history. The research assumes a failure mode occurring in the interface between the rock anchor and the surrounding grout. The constitutive behavior of the bonding interface is investigated for anchors subjected to cyclic one-way tensile loads. The model utilizes the static bond capacity curve as a basis, defining the ultimate bond sbuand the slip s1 at τ. A limited number of input parameters are required to apply the model. The model defines the bond-slip behavior with the belonging rock anchor capacity depending on the cyclic load level(τcy/τ), the cyclic load ratio(R= τcy/τcy), and the number of load cycles(N). The constitutive model is intended to model short anchor lengths representing an incremental length of a complete rock anchor.
基金supported by National Major Science and Technology Project“Horizontal well fracturing design optimization system”(No.2016ZX05023-001).
文摘In order to improve the effectiveness of shale gas stimulated reservoir volume(SRV),it is necessary to evaluate and study the permeability of different types of induced fractures in shale and its influential factors.In this paper,the mineral composition characteristics,reservoir pore and fracture characteristics of shale were investigated,and the permeability of three types of induced fractures in shale(i.e.,in-situ closed type,shear self-propped type and single-layer propped type)was tested.Besides,the effects of fracture type,fracture surface roughness,carbonate content,shale bedding and confining pressure on the permeability of induced fractures in shale reservoirs were studied systematically.The following research results were obtained.First,the permeabilityepressure relationship of in-situ closed fracture is in accordance with the Walsh theory.The permeability decreases with the increase of confining pressure and it is in the range of 0.13e16.75 mD.In-situ closed fracture plays the same role in increasing the productivity of shale gas reservoirs with or without proppant filling or dislocation.Second,compared with in-situ closed fracture permeability,the shear self-propped fracture permeability is 1e2 orders of magnitude(7.53e88.48 mD)higher,and single-layer propped fracture permeability is 2e3 orders of magnitude(9.98e771.82 mD)higher.Third,the larger the fracture surface roughness,the higher the fracture permeability.And there is a better positive correlation between the fractal dimension and the fracture permeability.Fourth,the permeabilityepressure relationship of shear self-propped fracture and single-layer propped fracture is,to some extent,deviated from the Walsh theory,which reflects the influence of self-propped point crushing,proppant embedding and crushing.In conclusion,the experimental results can be used as the reference for the selection of shale fracturing technologies and the optimization of parameters.
文摘Recently a research team at Ohio University,USA,conducted a unique full-scale feld load test to simulate the aeration pipe installations at a copper extraction mine operated in Chile.The overliner material taken from the mine was used in recreating the in situ conditions.Electric heaters were utilized to raise the temperature inside each pipe to simulate the essential element of the copper extraction process.The maximum vertical deflection reached by the test pipes was close to 20%,when the simulated heap pile height was 80 m.The plastic pipes and the overliner material were also tested in the laboratory.Based on the results,the maximum heap pile fll depth was recommended for the aeration system.The results indicated that the vertical deflection was the primary performance index for the aeration pipes installed in heap piles at mines.Lastly,the pipe made of polypropylene resin was super.
文摘When the pore pressure in a porous rock changes, stress arching will occur within the rock and the surrounding region. Stress arching ratio is defined as the total stress changes in the porous rock to the pore pressure change in the region. The region may have the same or different elastic moduli with the surrounding rock, which is usually referred to as inclusion or inhomogeneity. Stress arching is responsible for many geomechanical problems encountered during production or injection; in addition, it is a crucial parameter in stress estimation during field development. This paper aims to present laboratory measurements of vertical stress arching ratio in a material surrounding the inclusion(inhomogeneity).To the authors’ knowledge, few laboratory experiments have been reported on direct measurement of stress arching. The inclusion is a cylindrical sandstone(44 mm in diameter and 50 mm in height)embedded in a larger cylindrical sandstone(150 mm in diameter and 154 mm in height), both of which are made synthetically. These two parts are separated and sealed by a internal polyurethane sleeve.Vertical stress changes are recorded by a mini hydraulic sensor embedded in surrounding rock. Laboratory results are compared to those obtained by numerical models. These models are checked with analytical formulations. The results of numerical models show a good agreement with laboratory data.The numerical results also indicate that the sensor response is affected by elastic properties of the internal sleeve. According to the sensitivity analysis performed, in the absence of the internal sleeve,properties of the inclusion have significant effects on the surrounding stress arching induced.
基金Chengdu Municipal High-level Clinical Key Specialty Construction Project-Infectious Diseases Special ProjectChengdu Municipal Health Commission Project(No.2021250):Chengdu Municipal Science and Technology Bureau Project(No.2021-YF05-00536-SN)。
文摘Objective:To summarize the follow-up results of laboratory examination,echocardiographic and chest CT of patients with COVID-19 at the time of 2 years after discharge in Chengdu.Methods:A total of 29 COVID-19 survivors who have participated in the 1-year follow-up and 2-year follow-up at Public Health Clinical Center of Chengdu were included in our study.Their blood laboratory tests,echocardiography and chest CT results were analyzed in order to evaluate the long-term recovery of COVID-19 survivors.Results:The most common abnormal laboratory test results at the 2-year follow-up were increased serum fibronectin(21 cases,72.4%)and decreased NK cell counts(19 cases,65.5%).Compared with laboratory test results at the 1-year follow-up,platelet count,hydroxybutyrate dehydrogenase and creatine kinase isoenzyme were decreased(all P<0.05),while serum fibrinogen,triglyceride,insulin and non-specific immunoglobulin A were increased(all P<0.05).Serum specific total SARS-CoV-2 antibody amount in COVID-19 survivors at half a year after COVID-19 vaccine was significantly higher than that before vaccination.More than half of patients(55.2%)had normal echocardiography results at the 2-year follow-up,the main abnormal results of them were valve regurgitation(7 cases,24.1%)and reduced left ventricular diastolic function(9 cases,31.0%).Compared with 1-year follow-up,7 patients had fewer abnormal cardiac ultrasound results.28 cases underwent chest CT at the 2-year follow-up,the mainly abnormal results were ground glass shadow(17.9%),pulmonary nodules(diameter<6mm)(32.1%)and scattered cable shadow(39.3%).71.4%(20/28)of them had no significant change between the two chest CT results.Conclusion:The mainly abnormal blood laboratory indicators in COVID-19 survivors at 2-year follow-up after discharge were increased serum fibronectin and decreased NK cell counts.Although echocardiography and chest CT results were no significant change between 1-year follow-up and 2-year follow-up among COVID-19 survivors,there were still some patients whose abnormal results were decreasing.Serum specific total SARS-CoV-2 antibody amount in COVID-19 survivors at half a year after COVID-19 vaccine was still significantly higher than that before vaccination,but the amount of specific antibody had a downward trend with time.
文摘A complex Laboratory Developed Test(LDT)is a clinical test developed within a single laboratory.It is typically configured from many fea-ture constraints from clinical repositories,which are part of the existing Lab-oratory Information Management System(LIMS).Although these clinical repositories are automated,support for managing patient information with test results of an LDT is also integrated within the existing LIMS.Still,the support to configure LDTs design needs to be made available even in standard LIMS packages.The manual configuration of LDTs is a complex process and can generate configuration inconsistencies because many constraints between features can remain unsatisfied.It is a risky process and can lead patients to undergo unnecessary treatments.We proposed an optimized solution(opt-LDT)based on Genetic Algorithms to automate the configuration and resolve the inconsistencies in LDTs.Opt-LDT encodes LDT configuration as an optimization problem and generates a consistent configuration that satisfies the constraints of the features.We tested and validated opt-LDT for a local secondary care hospital in a real healthcare environment.Our results,averaged over ten runs,show that opt-LDT resolves 90%of inconsistencies while taking between 6 and 6.5 s for each configuration.Moreover,positive feedback based on a subjective questionnaire from clinicians regarding the performance,acceptability,and efficiency of opt-LDT motivates us to present our results for regulatory approval.
文摘The compelling case report by Xie et al,published in a renowned medical journal,is an excellent example of meticulous clinical evaluation,comprehensive labo-ratory testing,advanced imaging,and genetic analysis.The authors identified novel compound heterozygous mutations in the hemojuvelin gene of a patient diagnosed with juvenile hemochromatosis.They suggested that long-term,strategic phlebotomy might offer a novel therapeutic strategy for severe juvenile hemochromatosis,challenging the traditional treatment paradigms.
