Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)enables tumor vascular physiology to be assessed.Within the tumor tissue,contrast agents(gadolinium chelates)extravasate from intravascular into the extrava...Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)enables tumor vascular physiology to be assessed.Within the tumor tissue,contrast agents(gadolinium chelates)extravasate from intravascular into the extravascular extracellular space(EES),which results in a signal increase on T1-weighted MRI.The rate of contrast agents extravasation to EES in the tumor tissue is determined by vessel leakiness and blood flow.Thus,the signal measured on DCE-MRI represents a combination of permeability and perfusion.The semi-quantitative analysis is based on the calculation of heuristic parameters that can be extracted from signal intensity-time curves.These enhancing curves can also be deconvoluted by mathematical modeling to extract quantitative parameters that may reflect tumor perfusion,vascular volume,vessel permeability and angiogenesis.Because hepatocellular carcinoma(HCC)is a hypervascular tumor,many emerging therapies focused on the inhibition of angiogenesis.DCE-MRI combined with a pharmacokinetic model allows us to produce highly reproducible and reliable parametric maps of quantitative parameters in HCC.Successful therapies change quantitative parameters of DCE-MRI,which may be used as early indicators of tumor response to anti-angiogenesis agents that modulate tumor vasculature.In the setting of clinical trials,DCE-MRI may provide relevant clinical information on the pharmacodynamic and biologic effects of novel drugs,monitor treatment response and predict survival outcome in HCC patients.展开更多
Bone graft may be needed to fill bone defect in elderly patients with a metaphyseal comminuted distal radius fracture. In this retrospective, nonrandomized, single-surgeon study, we evaluated the clinical and radiolog...Bone graft may be needed to fill bone defect in elderly patients with a metaphyseal comminuted distal radius fracture. In this retrospective, nonrandomized, single-surgeon study, we evaluated the clinical and radiologic outcomes of using both dorsal locking plates with or without augmentation with mineralized collagen （MC） bone graft for elderly patients with dorsally metaphyseal comminuted radius fractures. Patients in group 1 （n = 12） were treated with dorsal locking plates with MC bone graft application into the metaphyseal bone defect, and those in group 2 （n - 12） only with dorsal locking plates. Clinical and radiologic parameters were determined at three and 12 months after surgery. At final follow-up, no significant difference was noted between the 2 groups in terms of palmar tilt and radial inclination （p - 0.80）; however, ulnar variance increased significantly in the group 2 treated with dorsal locking plates without augmentation （p〈0.05）. Functionally, there was no significant difference between the groups. Our preliminary study suggests that combination of MC as bone-graft substitutes and dorsal locking plates may be a usefully alternative for elderly patients with metaphyseal comminuted distal radius fracture.展开更多
Current management for spinal cord injury aims to reduce secondary damage and recover sensation and movement.Acute spinal cord injury is often accompanied by spinal cord compartment syndrome.Decompression by durotomy ...Current management for spinal cord injury aims to reduce secondary damage and recover sensation and movement.Acute spinal cord injury is often accompanied by spinal cord compartment syndrome.Decompression by durotomy and/or myelotomy attempts to relieve secondary damage by completelyrelieving the compression of the spinal cord,removing the necrotic tissue,decreasing edema,reducing hemorrhage,and improving blood circulation in the spinal cord.However,it is controversial whether durotomy and/or myelotomy after spinal cord injury are beneficial to neurological recovery.This review compares the clinical effects of durotomy with those of myelotomy in the treatment of spinal cord injury.We found that durotomy has been performed more than myelotomy in the clinic,and that durotomy may be safer and more effective than myelotomy.Durotomy performed in humans had positive effects on neurological function in 92.3% of studies in this review,while durotomy in animals had positive effects on neurological function in 83.3% of studies.Myelotomy procedures were effective in 80% of animal studies,but only one clinical study of myelotomy has reported positive results,of motor and sensory improvement,in humans.However,a number of new animal studies have reported that durotomy and myelotomy are ineffective for spinal cord injury.More clinical data,in the form of a randomized controlled study,are needed to understand the effectiveness of durotomy and myelotomy.展开更多
In this editorial,we review the work of Razali et al published in World J Gas-troenterology,with a particular focus on the effect of rs10889677 variation in the phosphatidylinositol 3-kinase(PI3K)pathway and buparlisi...In this editorial,we review the work of Razali et al published in World J Gas-troenterology,with a particular focus on the effect of rs10889677 variation in the phosphatidylinositol 3-kinase(PI3K)pathway and buparlisib on colitis-associated cancer.The role of PI3K in promoting cancer progression has been widely recognized,as it is involved in regulating the survival,differentiation,and prolif-eration of cancer cells.The complement Clq/TNF-related protein 6(CTRP6)is a newer tumor-associated factor.Recent studies have revealed the pro-tumor effect of CTRP6 in gastric cancer,hepatocellular carcinoma,colorectal cancer,and other gastrointestinal tumors through the PI3K pathway.This article attempts to reveal the mechanism through which the CTRP6 affects the development of digestive system tumors through the PI3K pathway by summarizing recent research.展开更多
In this editorial,we review the article published in World J Gastrointest Oncol 2019,11:1031-1042.We specifically focus on the occurrence,clinical characteristics,and risk factors of fluoropyrimidine drug-related card...In this editorial,we review the article published in World J Gastrointest Oncol 2019,11:1031-1042.We specifically focus on the occurrence,clinical characteristics,and risk factors of fluoropyrimidine drug-related cardiotoxicity in patients with gastrointestinal tumors.Despite significant advancements in diagnostic and therapeutic techniques that have reduced mortality rates associated with digestive system tumors,the incidence and mortality rates of treatment-related car-diotoxicity have been increasing,severely impacting the survival and prognosis of cancer patients.Fluoropyrimidine drugs are widely used as antimetabolites in the treatment of malignant tumors,including gastrointestinal tumors,and they represent the second largest class of drugs associated with cardiotoxicity.However,there is often a lack of awareness or understanding regarding their cardiotoxic effects and associated risks.展开更多
With the rapid development of intensive farming,the aquaculture industry uses a great many antibiotics for the prevention and treatment of bacterial diseases.Despite their therapeutic functions,the overuse and accumul...With the rapid development of intensive farming,the aquaculture industry uses a great many antibiotics for the prevention and treatment of bacterial diseases.Despite their therapeutic functions,the overuse and accumulation of antibiotics also pose a threat to aquaculture organisms.In the present study,ayu(Plecoglossus altivelis)was used as a fish model to study the impacts of ciprofloxacin(CIP)overuse on intestinal homeostasis and immune response during subsequent Pseudomonas plecoglossicida infection.Based on 16S rRNA gene amplification and Illumina sequencing,we found that CIP pre-exposure caused significant variation in intestinal microbiota,including increased species richness,altered microbiota composition and interaction networks,and increased metabolic dysfunction.Furthermore,immunohistochemical analysis indicated that CIP pre-exposure resulted in severe mucosal layer damage,goblet cell reduction,and epithelial cell necrosis of the intestinal barrier in infected ayu.Quantitative real-time polymerase chain reaction(qRT-PCR)showed that disruption of intestinal homeostasis impaired systemic antiinfection immune responses in the intestine,gill,spleen,and head kidney,while inhibiting IL-1β,TNF-α,and IL-10 expression and promoting TGF-βexpression.Our findings indicated that CIP administration can directly affect intestinal microbiota composition and intestinal integrity in ayu fish.This perturbation of intestinal homeostasis is likely responsible for the lower survival rate of hosts following subsequent infection as the capacity to mount an effective immune response is compromised.This study also provides preliminary clues for understanding the effects of antibiotic overuse on higher vertebrates through trophic transfer.展开更多
Currently,the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants,which leads to the continuous production of radioactive waste during m...Currently,the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants,which leads to the continuous production of radioactive waste during measurement.In addition,the real-time activity information of tritiated water cannot be obtained.To solve this problem,herein we present an online tritiated water measurement method based on plastic scintillators that used the optical transport process in the Geant 4 software toolkit to build a model of plastic scintillation detection for tritiated water.Through simulation,the basic geometric dimensions of the detector were determined.In this dimension,using one detector to measure for 3 h,when the tritiated water activity was 100 Bq/L,its resolution was 16%(16 Bq/L).In addition,calculations were performed for the presence of other background signals to obtain the minimum detectable concentration.展开更多
Hyphandria cunea is an insect that can damage hundreds of plants in its larval phase and needs to be placed under quarantine at an international level. Its hosts involve 600 plant species, including forest and fruit t...Hyphandria cunea is an insect that can damage hundreds of plants in its larval phase and needs to be placed under quarantine at an international level. Its hosts involve 600 plant species, including forest and fruit trees, shrubs, crops, vegetables, weeds and others. In 2006, we surveyed two Fraxinus chinensis Roxb stands, damaged to different degrees, after the invasion of H. cunea in the Changping district of the Beijing area. Given our survey of individual trees and investigation of bio-environmental factors, we pro-vide a preliminarily simulation of the growth situation of F. chinensis stands, damaged by H. cunea, by using the Forest Vegetation Simulator software （FVS）, which is supported by the ＂948＂ project from the State Forestry Administration of China. The results will provide a valuable reference in forecasting the effect of H. cunea and other invasive pests in China on forest ecological values.展开更多
This paper presents a new numerical model using the finite volume method with arbitrary polygonal elements,It is suitable for simulating the shallow water problem with com- plex topography and boundary conditions.The ...This paper presents a new numerical model using the finite volume method with arbitrary polygonal elements,It is suitable for simulating the shallow water problem with com- plex topography and boundary conditions.The calculated results show that this kind of method has the advantages of good stability,convenience of solving,easy programming,less,computing time and storage,high accuracy,ect.展开更多
Outbreak of COVID-19 is ongoing all over the world.Spine trauma is one of the most common types of trauma and will probably be encountered during the fight against COVID-19 and resumption of work and production.Patien...Outbreak of COVID-19 is ongoing all over the world.Spine trauma is one of the most common types of trauma and will probably be encountered during the fight against COVID-19 and resumption of work and production.Patients with unstable spine fractures or continuous deterioration of neurological function require emergency surgery.The COVID-19 epidemic has brought tremendous challenges to the diagnosis and treatment of such patients.To coordinate the diagnosis and treatment of infectious disease prevention and spine trauma so as to formulate a rigorous diagnosis and treatment plan and to reduce the disability and mortality of the disease,multidisciplinary collaboration is needed.This expert consensus is formulated in order to(1)prevent and control the epidemic,(2)diagnose and treat patients with spine trauma reasonably,and(3)reduce the risk of cross-infection between patients and medical personnel during the treatment.展开更多
CRM197(Cross-reacting material 197)是白喉毒素的无毒突变体,在生物制药领域具有非常广泛的应用前景。为了实现CRM197在大肠杆菌中的无标签、可溶表达,以替代现有昂贵、复杂的白喉杆菌分泌发酵工艺,文中对目的蛋白的序列进行优化,转...CRM197(Cross-reacting material 197)是白喉毒素的无毒突变体,在生物制药领域具有非常广泛的应用前景。为了实现CRM197在大肠杆菌中的无标签、可溶表达,以替代现有昂贵、复杂的白喉杆菌分泌发酵工艺,文中对目的蛋白的序列进行优化,转化大肠杆菌经IPTG诱导,目的蛋白获得了可溶性高表达,目的蛋白约占碎菌上清总蛋白的40%。超声破菌后、经阴离子交换、肝素亲和以及脱盐三步柱上层析获得纯度高于95%的CRM197样品。细胞毒性实验证明,CRM197的IC_(50)值是白喉毒素IC_(50)值的2.1×10~7倍,是白喉类毒素IC_(50)值的9.6倍,表明文中表达的CRM197是安全无毒的。随后,比较了高、低剂量的CRM197在小鼠体内的免疫原性,发现2μg组三免后的抗体滴度与20μg组的相当,可达1︰409 600。文中建立了CRM197的无标签、高效、可溶表达的大肠杆菌表达系和快速纯化体系,获得了具有较好免疫原性和安全性的重组蛋白,为该蛋白的进一步应用奠定了基础。展开更多
Gesture recognition is an important research in the field of human-computer interaction. Hand Gestures are strong variable and flexible, so the gesture recognition has always been an important challenge for the resear...Gesture recognition is an important research in the field of human-computer interaction. Hand Gestures are strong variable and flexible, so the gesture recognition has always been an important challenge for the researchers. In this paper, we first outlined the development of gestures recognition, and different classification of gestures based on different purposes. Then we respectively introduced common methods used in the process of gesture segmentation, feature extraction and recognition. Finally, the gesture recognition was summarized and the studying prospects were given.展开更多
FY-3C Microwave Temperature SounderⅡ(MWTS-Ⅱ)lacks observations at 23.8 GHz,31 GHz and 89 GHz,making it difficult to remove the data contaminated by precipitation in assimilation.In this paper,a fast forward operator...FY-3C Microwave Temperature SounderⅡ(MWTS-Ⅱ)lacks observations at 23.8 GHz,31 GHz and 89 GHz,making it difficult to remove the data contaminated by precipitation in assimilation.In this paper,a fast forward operator based on the Community Radiative Transfer Model(CRTM)was used to analyze the relationship between the observation minus background simulation(O-B)and the cloud fractions in different MWTS-Ⅱchannels.In addition,based on the community Gridpoint Statistical Interpolation(GSI)system,the radiation brightness temperature of the MWTS-Ⅱwas assimilated in the regional Numerical Weather Prediction(NWP)model.In the process of assimilation,Visible and Infrared Radiometer(VIRR)cloud detection products were matched to MWTS-Ⅱpixels for precipitation detection.For typhoon No.18 in 2014,impact tests of MWTS-Ⅱdata assimilation was carried out.The results show that,though the bias observation minus analysis(O-A)of assimilated data can be reduced by quality control only with|O-B|<3 K;however,the O-A becomes much smaller while the precipitation detection is performed with Fvirr<0.9(VIRR cloud fraction threshold of 0.9).Besides,the change of the environmental field around the typhoon is more conducive to make the simulated track closer to the observation.The 72-hour typhoon track simulation error also shows that,after the precipitation detection,the error of simulated typhoon track is significantly reduced,which reflects the validity of a precipitation detection method based on a double criterion of|O-B|<3 K and Fvirr<0.9.展开更多
The jet flow with high water head happens very often in hydraulic engineering. In this paper, starting from the viewpoint of random hydraulics, the experimental research work on the problem of percussion action of the...The jet flow with high water head happens very often in hydraulic engineering. In this paper, starting from the viewpoint of random hydraulics, the experimental research work on the problem of percussion action of the jet flow related to the apron slab.Stochastic theory and random time series are employed to analyse the sample function x(t) ,its x(t) and x(t) and their corelations μ on M. The working process of the apron during the variation of flow discharge has been observed and the machanism of failure of apron slab is discussed. The lift force due to the action of jet flow is analysed and the conditions of improving the safety factors of apron slab are presented.展开更多
文摘Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)enables tumor vascular physiology to be assessed.Within the tumor tissue,contrast agents(gadolinium chelates)extravasate from intravascular into the extravascular extracellular space(EES),which results in a signal increase on T1-weighted MRI.The rate of contrast agents extravasation to EES in the tumor tissue is determined by vessel leakiness and blood flow.Thus,the signal measured on DCE-MRI represents a combination of permeability and perfusion.The semi-quantitative analysis is based on the calculation of heuristic parameters that can be extracted from signal intensity-time curves.These enhancing curves can also be deconvoluted by mathematical modeling to extract quantitative parameters that may reflect tumor perfusion,vascular volume,vessel permeability and angiogenesis.Because hepatocellular carcinoma(HCC)is a hypervascular tumor,many emerging therapies focused on the inhibition of angiogenesis.DCE-MRI combined with a pharmacokinetic model allows us to produce highly reproducible and reliable parametric maps of quantitative parameters in HCC.Successful therapies change quantitative parameters of DCE-MRI,which may be used as early indicators of tumor response to anti-angiogenesis agents that modulate tumor vasculature.In the setting of clinical trials,DCE-MRI may provide relevant clinical information on the pharmacodynamic and biologic effects of novel drugs,monitor treatment response and predict survival outcome in HCC patients.
文摘Bone graft may be needed to fill bone defect in elderly patients with a metaphyseal comminuted distal radius fracture. In this retrospective, nonrandomized, single-surgeon study, we evaluated the clinical and radiologic outcomes of using both dorsal locking plates with or without augmentation with mineralized collagen （MC） bone graft for elderly patients with dorsally metaphyseal comminuted radius fractures. Patients in group 1 （n = 12） were treated with dorsal locking plates with MC bone graft application into the metaphyseal bone defect, and those in group 2 （n - 12） only with dorsal locking plates. Clinical and radiologic parameters were determined at three and 12 months after surgery. At final follow-up, no significant difference was noted between the 2 groups in terms of palmar tilt and radial inclination （p - 0.80）; however, ulnar variance increased significantly in the group 2 treated with dorsal locking plates without augmentation （p〈0.05）. Functionally, there was no significant difference between the groups. Our preliminary study suggests that combination of MC as bone-graft substitutes and dorsal locking plates may be a usefully alternative for elderly patients with metaphyseal comminuted distal radius fracture.
基金financially supported by the National Key Research and Development Program of China,No.2016YFC1100100(to XDG)
文摘Current management for spinal cord injury aims to reduce secondary damage and recover sensation and movement.Acute spinal cord injury is often accompanied by spinal cord compartment syndrome.Decompression by durotomy and/or myelotomy attempts to relieve secondary damage by completelyrelieving the compression of the spinal cord,removing the necrotic tissue,decreasing edema,reducing hemorrhage,and improving blood circulation in the spinal cord.However,it is controversial whether durotomy and/or myelotomy after spinal cord injury are beneficial to neurological recovery.This review compares the clinical effects of durotomy with those of myelotomy in the treatment of spinal cord injury.We found that durotomy has been performed more than myelotomy in the clinic,and that durotomy may be safer and more effective than myelotomy.Durotomy performed in humans had positive effects on neurological function in 92.3% of studies in this review,while durotomy in animals had positive effects on neurological function in 83.3% of studies.Myelotomy procedures were effective in 80% of animal studies,but only one clinical study of myelotomy has reported positive results,of motor and sensory improvement,in humans.However,a number of new animal studies have reported that durotomy and myelotomy are ineffective for spinal cord injury.More clinical data,in the form of a randomized controlled study,are needed to understand the effectiveness of durotomy and myelotomy.
文摘In this editorial,we review the work of Razali et al published in World J Gas-troenterology,with a particular focus on the effect of rs10889677 variation in the phosphatidylinositol 3-kinase(PI3K)pathway and buparlisib on colitis-associated cancer.The role of PI3K in promoting cancer progression has been widely recognized,as it is involved in regulating the survival,differentiation,and prolif-eration of cancer cells.The complement Clq/TNF-related protein 6(CTRP6)is a newer tumor-associated factor.Recent studies have revealed the pro-tumor effect of CTRP6 in gastric cancer,hepatocellular carcinoma,colorectal cancer,and other gastrointestinal tumors through the PI3K pathway.This article attempts to reveal the mechanism through which the CTRP6 affects the development of digestive system tumors through the PI3K pathway by summarizing recent research.
文摘In this editorial,we review the article published in World J Gastrointest Oncol 2019,11:1031-1042.We specifically focus on the occurrence,clinical characteristics,and risk factors of fluoropyrimidine drug-related cardiotoxicity in patients with gastrointestinal tumors.Despite significant advancements in diagnostic and therapeutic techniques that have reduced mortality rates associated with digestive system tumors,the incidence and mortality rates of treatment-related car-diotoxicity have been increasing,severely impacting the survival and prognosis of cancer patients.Fluoropyrimidine drugs are widely used as antimetabolites in the treatment of malignant tumors,including gastrointestinal tumors,and they represent the second largest class of drugs associated with cardiotoxicity.However,there is often a lack of awareness or understanding regarding their cardiotoxic effects and associated risks.
基金supported by the Key Research and Development Project of Zhejiang Province(2021C02062)National Natural Science Foundation of China(32173004,31972821)+2 种基金Natural Science Foundation of Zhejiang Province(LZ18C190001)Natural Science Foundation of Ningbo City(202003N4011)Research Project of State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products(2010DS700124-ZZ2008)。
文摘With the rapid development of intensive farming,the aquaculture industry uses a great many antibiotics for the prevention and treatment of bacterial diseases.Despite their therapeutic functions,the overuse and accumulation of antibiotics also pose a threat to aquaculture organisms.In the present study,ayu(Plecoglossus altivelis)was used as a fish model to study the impacts of ciprofloxacin(CIP)overuse on intestinal homeostasis and immune response during subsequent Pseudomonas plecoglossicida infection.Based on 16S rRNA gene amplification and Illumina sequencing,we found that CIP pre-exposure caused significant variation in intestinal microbiota,including increased species richness,altered microbiota composition and interaction networks,and increased metabolic dysfunction.Furthermore,immunohistochemical analysis indicated that CIP pre-exposure resulted in severe mucosal layer damage,goblet cell reduction,and epithelial cell necrosis of the intestinal barrier in infected ayu.Quantitative real-time polymerase chain reaction(qRT-PCR)showed that disruption of intestinal homeostasis impaired systemic antiinfection immune responses in the intestine,gill,spleen,and head kidney,while inhibiting IL-1β,TNF-α,and IL-10 expression and promoting TGF-βexpression.Our findings indicated that CIP administration can directly affect intestinal microbiota composition and intestinal integrity in ayu fish.This perturbation of intestinal homeostasis is likely responsible for the lower survival rate of hosts following subsequent infection as the capacity to mount an effective immune response is compromised.This study also provides preliminary clues for understanding the effects of antibiotic overuse on higher vertebrates through trophic transfer.
基金supported by the National Natural Science Foundation of China(No.12105029)。
文摘Currently,the liquid scintillation method is widely used to measure the activity of tritiated water in the primary circuit of nuclear power plants,which leads to the continuous production of radioactive waste during measurement.In addition,the real-time activity information of tritiated water cannot be obtained.To solve this problem,herein we present an online tritiated water measurement method based on plastic scintillators that used the optical transport process in the Geant 4 software toolkit to build a model of plastic scintillation detection for tritiated water.Through simulation,the basic geometric dimensions of the detector were determined.In this dimension,using one detector to measure for 3 h,when the tritiated water activity was 100 Bq/L,its resolution was 16%(16 Bq/L).In addition,calculations were performed for the presence of other background signals to obtain the minimum detectable concentration.
文摘Hyphandria cunea is an insect that can damage hundreds of plants in its larval phase and needs to be placed under quarantine at an international level. Its hosts involve 600 plant species, including forest and fruit trees, shrubs, crops, vegetables, weeds and others. In 2006, we surveyed two Fraxinus chinensis Roxb stands, damaged to different degrees, after the invasion of H. cunea in the Changping district of the Beijing area. Given our survey of individual trees and investigation of bio-environmental factors, we pro-vide a preliminarily simulation of the growth situation of F. chinensis stands, damaged by H. cunea, by using the Forest Vegetation Simulator software （FVS）, which is supported by the ＂948＂ project from the State Forestry Administration of China. The results will provide a valuable reference in forecasting the effect of H. cunea and other invasive pests in China on forest ecological values.
文摘This paper presents a new numerical model using the finite volume method with arbitrary polygonal elements,It is suitable for simulating the shallow water problem with com- plex topography and boundary conditions.The calculated results show that this kind of method has the advantages of good stability,convenience of solving,easy programming,less,computing time and storage,high accuracy,ect.
基金National Natural Science Foundation of China(81873999,81672158)National Key R&D Program of China(2016YFC1100100).These funding agencies had no role in study design,collection/analyses of data,decision to publish,or manuscript preparation.
文摘Outbreak of COVID-19 is ongoing all over the world.Spine trauma is one of the most common types of trauma and will probably be encountered during the fight against COVID-19 and resumption of work and production.Patients with unstable spine fractures or continuous deterioration of neurological function require emergency surgery.The COVID-19 epidemic has brought tremendous challenges to the diagnosis and treatment of such patients.To coordinate the diagnosis and treatment of infectious disease prevention and spine trauma so as to formulate a rigorous diagnosis and treatment plan and to reduce the disability and mortality of the disease,multidisciplinary collaboration is needed.This expert consensus is formulated in order to(1)prevent and control the epidemic,(2)diagnose and treat patients with spine trauma reasonably,and(3)reduce the risk of cross-infection between patients and medical personnel during the treatment.
文摘CRM197(Cross-reacting material 197)是白喉毒素的无毒突变体,在生物制药领域具有非常广泛的应用前景。为了实现CRM197在大肠杆菌中的无标签、可溶表达,以替代现有昂贵、复杂的白喉杆菌分泌发酵工艺,文中对目的蛋白的序列进行优化,转化大肠杆菌经IPTG诱导,目的蛋白获得了可溶性高表达,目的蛋白约占碎菌上清总蛋白的40%。超声破菌后、经阴离子交换、肝素亲和以及脱盐三步柱上层析获得纯度高于95%的CRM197样品。细胞毒性实验证明,CRM197的IC_(50)值是白喉毒素IC_(50)值的2.1×10~7倍,是白喉类毒素IC_(50)值的9.6倍,表明文中表达的CRM197是安全无毒的。随后,比较了高、低剂量的CRM197在小鼠体内的免疫原性,发现2μg组三免后的抗体滴度与20μg组的相当,可达1︰409 600。文中建立了CRM197的无标签、高效、可溶表达的大肠杆菌表达系和快速纯化体系,获得了具有较好免疫原性和安全性的重组蛋白,为该蛋白的进一步应用奠定了基础。
文摘Gesture recognition is an important research in the field of human-computer interaction. Hand Gestures are strong variable and flexible, so the gesture recognition has always been an important challenge for the researchers. In this paper, we first outlined the development of gestures recognition, and different classification of gestures based on different purposes. Then we respectively introduced common methods used in the process of gesture segmentation, feature extraction and recognition. Finally, the gesture recognition was summarized and the studying prospects were given.
基金Natural Science Foundation of China(41505082)Special Scientific Research Fund of Meteorology in the Public Welfare Profession of China(GYHY201506002,GYHY201506022)
文摘FY-3C Microwave Temperature SounderⅡ(MWTS-Ⅱ)lacks observations at 23.8 GHz,31 GHz and 89 GHz,making it difficult to remove the data contaminated by precipitation in assimilation.In this paper,a fast forward operator based on the Community Radiative Transfer Model(CRTM)was used to analyze the relationship between the observation minus background simulation(O-B)and the cloud fractions in different MWTS-Ⅱchannels.In addition,based on the community Gridpoint Statistical Interpolation(GSI)system,the radiation brightness temperature of the MWTS-Ⅱwas assimilated in the regional Numerical Weather Prediction(NWP)model.In the process of assimilation,Visible and Infrared Radiometer(VIRR)cloud detection products were matched to MWTS-Ⅱpixels for precipitation detection.For typhoon No.18 in 2014,impact tests of MWTS-Ⅱdata assimilation was carried out.The results show that,though the bias observation minus analysis(O-A)of assimilated data can be reduced by quality control only with|O-B|<3 K;however,the O-A becomes much smaller while the precipitation detection is performed with Fvirr<0.9(VIRR cloud fraction threshold of 0.9).Besides,the change of the environmental field around the typhoon is more conducive to make the simulated track closer to the observation.The 72-hour typhoon track simulation error also shows that,after the precipitation detection,the error of simulated typhoon track is significantly reduced,which reflects the validity of a precipitation detection method based on a double criterion of|O-B|<3 K and Fvirr<0.9.
文摘The jet flow with high water head happens very often in hydraulic engineering. In this paper, starting from the viewpoint of random hydraulics, the experimental research work on the problem of percussion action of the jet flow related to the apron slab.Stochastic theory and random time series are employed to analyse the sample function x(t) ,its x(t) and x(t) and their corelations μ on M. The working process of the apron during the variation of flow discharge has been observed and the machanism of failure of apron slab is discussed. The lift force due to the action of jet flow is analysed and the conditions of improving the safety factors of apron slab are presented.
