Over the past two decades,transcatheter arterial embolization has become the first-line therapy for the management of upper gastrointestinal bleeding that is refractory to endoscopic hemostasis.Advances in catheter-ba...Over the past two decades,transcatheter arterial embolization has become the first-line therapy for the management of upper gastrointestinal bleeding that is refractory to endoscopic hemostasis.Advances in catheter-based techniques and newer embolic agents, as well as recognition of the effectiveness of minimally invasive treatment options,have expanded the role of interventional radiology in the management of hemorrhage for a variety of indications,such as peptic ulcerbleeding,malignant disease,hemorrhagic Dieulafoy lesions and iatrogenic or trauma bleeding.Transcatheter interventions include the following:selective embolization of the feeding artery,sandwich coil occlusion of the gastroduodenal artery,blind or empiric embolization of the supposed bleeding vessel based on endoscopic findings and coil pseudoaneurysm or aneurysm embolization by three-dimensional sac packing with preservation of the parent artery.Transcatheter embolization is a fast,safe and effective,minimally invasive alternative to surgery when endoscopic treatment fails to control bleeding from the upper gastrointestinal tract.This article reviews the various transcatheter endovascular techniques and devices that are used in a variety of clinical scenarios for the management of hemorrhagic gastrointestinal emergencies.展开更多
The research roots of 19fluorine （19F） magnetic resonance imaging （MRI） date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imagi...The research roots of 19fluorine （19F） magnetic resonance imaging （MRI） date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, ~gF/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of ~gF into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.展开更多
The primary emphasis of this research was to investigate the foundations of phthalate（PAEs） pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalat...The primary emphasis of this research was to investigate the foundations of phthalate（PAEs） pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalate total content in per unit mass and unit surface area of pollutant sources. Through surveying and evaluating the coefficient of volatile strength of PAEs from typical plastic products, this research carried out reasonable classification of PAEs pollutant sources into three categories and then investigated the relationship amongst the coefficient of volatile strength as well as other environmental factors and the concentration level of total PAEs in indoor air measured in environment chambers.Research obtained phthalate concentration results under different temperature, humidity,the coefficient of volatile strength and the closed time through the chamber experiment. In addition, this study further explored the correlation and ratio of influencing factors that affect the concentration level of total PAEs in environment chambers, including environmental factors, the coefficient of volatile strengths of PAEs and contents of total PAEs in plastic products. The research created an improved database system of phthalate the coefficient of volatile strengths of each type of plastic goods, and tentatively revealed that the volatile patterns of PAEs from different typical plastic goods, finally confirmed that the coefficient of volatile strengths of PAEs is a major factor that affects the indoor air total PAEs concentration, which laid a solid foundation for further establishing the volatile equation of PAEs from plastic products.展开更多
Switch policy is essential for small cells to properly serve variable number of users in an energy efficient way.However,frequently switching small cell base stations(SBSs) may increase the network operating cost,espe...Switch policy is essential for small cells to properly serve variable number of users in an energy efficient way.However,frequently switching small cell base stations(SBSs) may increase the network operating cost,especially when there is an nonnegligible start-up energy cost.To this end,by observing the variety of user number,we focus on the design of a switch policy which minimize the cumulative energy consumption.A given user transmission rate is guaranteed and the capability of SBSs are limited as well.According to the knowledge on user number variety,we classify the energy consumption problem into two cases.In complete information case,to minimize the cumulative energy consumption,an offline solution is proposed according to critical segments.A heuristic algorithm for incomplete information case(HAIIC) is proposed by tracking the difference of cumulative energy consumption.The upper bound of the Energy Consumption Ratio(ECR) for HAIIC is derived as well.In addition,a practical Q-learning based probabilistic policy is proposed.Simulation results show that the proposed HAIIC algorithm is able to save energy efficiently.展开更多
AIMTo investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).METHODSRotational C-arm CT (RCT) under rapid ...AIMTo investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).METHODSRotational C-arm CT (RCT) under rapid ventricular pacing was performed in 57 consecutive patients with severe aortic stenosis as part of the pre-procedural cardiac catheterization. With prototype software each RCT data set was segmented using a 3D heart model. From that the line of perpendicularity curve was obtained that generates a perpendicular view of the aortic annulus according to the right-cusp rule. To evaluate the accuracy of a model-based overlay we compared model- and expert-derived aortic root diameters.RESULTSFor all 57 patients in the RCT cohort diameter measurements were obtained from two independent operators and were compared to the model-based measurements. The inter-observer variability was measured to be in the range of 0°-12.96° of angular C-arm displacement for two independent operators. The model-to-operator agreement was 0°-13.82°. The model-based and expert measurements of aortic root diameters evaluated at the aortic annulus (r = 0.79, P < 0.01), the aortic sinus (r = 0.93, P < 0.01) and the sino-tubular junction (r = 0.92, P < 0.01) correlated on a high level and the Bland-Altman analysis showed good agreement. The interobserver measurements did not show a significant bias.CONCLUSIONAutomatic segmentation of the aortic root using an anatomical model can accurately predict an optimal C-arm configuration, potentially simplifying current clinical workflows before and during TAVR.展开更多
Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicabil...Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicability of an advanced cardiovascular magnetic resonance(CMR)whole heart imaging approach utilizing nonselective excitation and compressed sensing for anatomical assessment and interventional guidance of CHD patients in comparison to conventional dynamic CMR angiography.Methods:86 consecutive pediatric patients and adults with congenital heart disease(age,1 to 74 years;mean,35 years)underwent CMR imaging including a freebreathing,ECG-triggered 3D nonselective SSFP whole heart acquisition using compressed SENSE(nsWHcs).Anatomical assessability and signal intensity ratio(SIR)measurements were compared with conventional dynamic 3D-/4D-MR angiography.Results:The most frequent diagnoses were partial anomalous pulmonary venous drainage(17/86,20%),transposition of the great arteries(15/86,17%),tetralogy of Fallot(12/86,14%),and a single ventricle(7/86,8%).Image quality of nsWHcs was rated as excellent/good in 98%of patients.nsWHcs resulted in a reliable depiction of all large thoracic vessels(anatomic assessability,99%–100%)and the proximal segments of coronary arteries and coronary sinus(>90%).nsWHcs achieved a homogenously distributed SIR in all cardiac cavities and thoracic vessels without a significant difference between pulmonary and systemic circulation(10.9±3.5 and 10.6±3.4;p=0.15),while 3D angiography showed significantly increased SIR for targeted vs.non-targeted circulation(PA-angiography,15.2±8.1 vs.5.8±3.6,p<0.001;PV-angiography,7.0±3.9 vs.17.3±6.8,p<0.001).Conclusions:The proposed nsWHcs imaging approach provided a consistently high image quality and a homogeneous signal intensity distribution within the pulmonary and systemic circulation in pediatric patients and adults with a wide spectrum of congenital heart diseases.nsWHcs enabled detailed anatomical assessment and three-dimensional reconstruction of all cardiac cavities and large thoracic vessels and can be regarded particularly useful for preprocedural planning and interventional guidance in CHD patients.展开更多
Cerebral arteriovenous malformations (AVMs) are a type of vascular anomaly consisting of large intertwined vascular growth (Nidus) that is prone to serious hemorrhaging and can result in patient death if left untreate...Cerebral arteriovenous malformations (AVMs) are a type of vascular anomaly consisting of large intertwined vascular growth (Nidus) that is prone to serious hemorrhaging and can result in patient death if left untreated. Intervention through surgical clipping of feeding and draining vessels to the Nidus is a common treatment. However, identification of which vessels to clip is challenging even to experienced surgeons aided by conventional image guidance systems. The lumped modeling for the Cerebral Arteriovenous Malformation (CAVM) hemodynamic analysis is of high importance in clinical world. As part of the treatment planning for CAVM, it is difficult for doctors to assess the NIDUS part, which may get rupture while inserting catheter. In this paper, we have proposed a non-invasive method for assessing the hemodynamic condition of AVM. The measurement of flow and pressure without intervention along the vessel is a big challenge due to occlusion, bending and thinning of the vessel in Arteriovenous Malformation patients. In this paper, we analyzed a lumped model for the vascular malformation using various imaging multi-modalities that help to analyze CAVM Structures.展开更多
Aim: Neurovascular abnormalities are extremely complex, due to the multitude of factors acting simultaneously on cerebral hemodynamics. Cerebral Arteriovenous Malformation (CAVM) hemo-dynamic in one of the vascular ab...Aim: Neurovascular abnormalities are extremely complex, due to the multitude of factors acting simultaneously on cerebral hemodynamics. Cerebral Arteriovenous Malformation (CAVM) hemo-dynamic in one of the vascular abnormality condition results changes in the vessels structures and hemodynamics in blood vessels. The challenge is segmenting accurate vessel region to measure hemodynamics of CAVM patients. The clinical procedure is in-vivo method to measure hemodynamics. The catheter-based procedure is difficult, as it is sometimes difficult to reach vessels sub-structures. Methods: In this paper, we have proposed adaptive vessel segmentation based on threshold technique for CAVM patients. We have compared different adaptive methods for vessel segmentation of CAVM structures. The sub-structures are modeled using lumped model to measure hemodynamics non-invasively. Results: Twenty-three CAVM patients with 150 different vessel locations of DSA datasets were studied as part of the adaptive segmentation. 30 simulated data has been evaluated for more than 150 vessels locations for sub-segmentation of vessels. The segmentation results are evaluated with accuracy of 93%. The computed p-value is smaller than the significance level 0.05. Conclusion: The adaptive segmentation using threshold based produces accurate vessel segmentation, results in better accuracy of hemodynamic measurements for DSA images for CAVM patients. The proposed adaptive segmentation helps clinicians to measure hemodynamic non-invasively for the segmented sub-structures of vessels.展开更多
Purpose: To generate parametric images of tumor hypoxia in a tumor-bearing rat model using voxel-based compartmental analysis of dynamic fluorine-18 labeled misonidazole (18F-FMISO) microPET? images, and to compare th...Purpose: To generate parametric images of tumor hypoxia in a tumor-bearing rat model using voxel-based compartmental analysis of dynamic fluorine-18 labeled misonidazole (18F-FMISO) microPET? images, and to compare the parametric images thus derived with static “late” 18F-FMISO microPET? images for the detection of tumor hypoxia. Materials and Methods: Nude rats bearing HT-29 colorectal carcinoma xenografts (≈1.5 - 2 cm in diameter) in the right hind limb were positioned in a custom-fabricated, animal-specific foam mold. Animals were injected via the tail vein with ≈55.5 MBq 18F-FMISO and continuously imaged for either 60 or 120 minutes, with additional late static images up to 3 hour post-injection. The raw list-mode data was reconstructed into 37 - 64 frames with earlier frames of shorter time durations (12 - 15 seconds) and later frames of longer durations (up to 300 seconds). Time activity curves (TACs) were generated over regions encompassing the tumor as well as an artery, the latter for use as an input function. A beta version of a compartmental modeling package (BioGuide?, Philips Healthcare) was used to generate parametric images of k3 and Ki, rate constants of entrapment and flux of 18F-FMISO, respectively. Results: Data for 7 HT-29 tumor xenografts were presented, 6 of which yielded clear areas of tumor hypoxia as defined by Ki/k3 maps. Importantly, intratumoral foci with high 18F-FMISO uptakes on the late images did not always exhibit high Ki/k3 values and may there- fore represent false-positives for radiobiologically significant hypoxia. Conclusions: This study attempts to quantify tumor hypoxia using compartmental analysis of dynamic 18F-FMISO PET images in rodent xenograft tumor models. The results demonstrate feasibility of the approach in small-animal imaging studies, and provide evidence for the possible unreliability of late-time static imaging of 18F-FMISO PET in identifying tumor hypoxia.展开更多
To brew tea correctly is very important to absorb the tea nutrition for people.The dynamic changes of the main compositions in brewing Pu'erh tea processing with different conditions were studied.Three different t...To brew tea correctly is very important to absorb the tea nutrition for people.The dynamic changes of the main compositions in brewing Pu'erh tea processing with different conditions were studied.Three different temperatures and eight times were designed to study the effects on the tea infusion quality.The index t0.5min(50%concentration of compounds in tea infusion) was used to evaluate the extract speed of compound in this experiment.The results showed that caffeine solubility speed at 80℃ was the highest to compare with tea polyphenols,amino acid,caffeine,soluble sugar,theaflavins and theabrownine,t0.5min of caffeine was 4.8 min,amino acid 10.3min was the second,the third one was tea polyphenols,soluble sugar was the lowest.We also found in different infusion temperature the t0.5min of compounds was distinguishing.With increasing the temperature all t0.5min of six compounds were shorter.However,the change regulations of t0.5min for all compounds in 90℃ and 100℃ were similar to in 80℃.Total quality score(TQS) were applied to evaluate the quality of tea infusion.The results found the TQS score of infusion was higher with the temperature rising,and the temperature to brew best quality infusion was 100℃ for 4-5min.According to the multiple regression analysis between sensory assessments and chemical components of Pu'erh tea we suggested the TQS was mainly affected by theaflavins,amino acid,soluble sugar and theabrowine four factors in 100℃.展开更多
The recent research achievements about the mechanisms of beneficial health effects of tea polyphenols and the epidemiological investigation on anti-cancer,anti-cardiovascular diseases,and anti-obesity through tea cons...The recent research achievements about the mechanisms of beneficial health effects of tea polyphenols and the epidemiological investigation on anti-cancer,anti-cardiovascular diseases,and anti-obesity through tea consumption were reviewed.It is proved that reactive oxygen species is the main reason to induce cell mutation,DNA damage,obesity,high blood pressure and many kinds of cancers.Tea catechins and theaflavins have excellent bioactivity on scavenging ROS due to their characteristic structure feature of phenolic hydroxyl group,which means drinking tea could prevent diseases.Epidemidogical investigations also showed that tea consumption could reduce the risk of lung cancer,gastric cancer,bladder cancer,and so on.However,the frequency of tea drinking or tea consumption amounts significantly affected the prevention efficiency.The epidemiologic investigations also find that drink green tea,especial black tea is useful to modify the cardiovascular diseases.In vivo and vitro tests showed that tea supplement could moderate the metabolism of blood lipid and prevent obesity.These indicated that tea and tea extracts might reduce the risk of many diseases.展开更多
Mobile broadcasting services provided by converged networks do aid in satisfying users' demands for popular multimedia content while unicasting services offer personalized experiences for users.We analyze hybrid b...Mobile broadcasting services provided by converged networks do aid in satisfying users' demands for popular multimedia content while unicasting services offer personalized experiences for users.We analyze hybrid broadcasting unicasting framework from the perspective of network economics,where content provider(CP) figures out the cooperation of broadcasting and unicasting services providers,as long as their pricing strategies.To this end,a contract-based content delivery scheme is proposed.The profit of CP depends on users' preference and satisfaction for unicasting and broadcasting transmission.CP provides different users with distinctive data packages.The intent is to maximize its own profit.By classifying users into different types,the optimal contract in close form is derived.Numerical results show that the proposed optimal contract is able to generate incentive for users to employ broadcasting transmission,which further benefits both the CP and users.展开更多
In many medical fields,spatial localization of devices is of paramount importance to e.g.deliver treatments correctly or to perform accurate diagnostic evaluations.Among the different technologies available,optical lo...In many medical fields,spatial localization of devices is of paramount importance to e.g.deliver treatments correctly or to perform accurate diagnostic evaluations.Among the different technologies available,optical localization in the visible band of the spectrum offers many advantages:minimum interference with other instruments,flexibility in position of the devices used and extra features such as patient/operator surface tracking or vital signs monitoring.Its application in the domain of radiotherapy is novel,and potentially very beneficial.In this work we introduced a workflow to test the reliability of one of these systems,developed in house,to localize an ultrasound transducer for ultrasound guided radiation therapy(USg RT).Accuracy,precision,latency,sensitive volume and sensitivity to light intensity were evaluated.The workflow we proposed allowed us to establish that,while all the clinically relevant parameters of the system are acceptable,accuracy in locating the transducer could be as intended purpose of the system.展开更多
Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intri...Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.展开更多
In this study, we aimed to investigate the functional network changes that occur in patients with lower back pain(LBP). We also investigated the link between LBP and the small-world properties of functional networks w...In this study, we aimed to investigate the functional network changes that occur in patients with lower back pain(LBP). We also investigated the link between LBP and the small-world properties of functional networks within the brain. Functional MRI(fMRI) was performed on 20 individuals with LBP and 17 age and gender-matched normal controls during the resting state. The severity of the pain in the individuals with LBP ranged from 5 to 8 on a 0–10 scale, with 0 indicating no pain. Network-based statistics were performed to investigate the differences between the brain networks of individuals with LBP and those of normal controls. Several small-world parameters of brain networks were calculated, including the clustering coefficient, characteristic path length, local efficiency, and global efficiency. These criteria reflect the overall network efficiency. The brain networks in the individuals with LBP due to herniation of a lumbar disc demonstrated a significantly longer characteristic path length as well as a lower clustering coefficient, global efficiency, and local efficiency compared to those in control subjects. We found that LBP patients tended to have unstable and inefficient brain networks when compared with healthy controls. In addition, LBP individuals showed significantly decreased functional connectivity in the anterior cingulate cortex, middle cingulate cortex, post cingulate cortex, inferior frontal gyrus, middle temporal gyrus, occipital gyrus, postcentral gyrus, precentral gyrus, supplementary motor area, thalamus, fusiform, caudate, and cerebellum. We believe that these regions may be involved in the pathophysiology of lower back pain.展开更多
Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled...Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled by incorporating secondary optical components.Metallic nanostructures supporting plasmonic resonances are an interesting alternative to this approach due to their strong light–matter interaction,which facilitates control over light emission without requiring external secondary optical components.This review discusses new methods that enhance the efficiencies of LEDs using nanostructured metals.This is an emerging field that incorporates physics,materials science,device technology and industry.First,we provide a general overview of state-of-the-art LED lighting,discussing the main characteristics required of both quantum wells and color converters to efficiently generate white light.Then,we discuss the main challenges in this field as well as the potential of metallic nanostructures to circumvent them.We review several of the most relevant demonstrations of LEDs in combination with metallic nanostructures,which have resulted in light-emitting devices with improved performance.We also highlight a few recent studies in applied plasmonics that,although exploratory and eminently fundamental,may lead to new solutions in illumination.展开更多
Background In recent years,computers have been intensively used at home.In contrast to paper-based books and documents,computer screen is self-illuminated with larger screen-background luminance difference,which great...Background In recent years,computers have been intensively used at home.In contrast to paper-based books and documents,computer screen is self-illuminated with larger screen-background luminance difference,which greatly induces visual discomfort.To compensate for that,one effective solution is to offer an additional background luminance.In this study,we investigated whether and to what extent additional background lighting is needed in looking at a computer display comfortably.Methods In this study,60 healthy children aged from 9 to 12 years and 58 adults aged from 21 to 39 years participated in the experiments.They were asked to choose their most preferred background luminance intensities at three screen luminance levels.The data were analyzed by Matlab （R2012b） and SPSS 20.0.Results Both children and adult participants selected a non-dark background as their comfortable lighting condition when watching a computer display （children：t （59）=22.0,P 〈0.01,adults：t （57）=15.5,P 〈0.01）.Comparatively,children preferred brighter background in general （F （1,116）=7.0,P 〈0.01）.More importantly,participants＇ preferred background luminance levels were linearly correlated with screen luminance intensities （children：slope=0.97,R2=0.98; adults：slope=0.38,R2=1.00）.Conclusion These results indicate that varying background luminance to maintain screen-background luminance ratio is beneficial to human visual comfort.展开更多
文摘Over the past two decades,transcatheter arterial embolization has become the first-line therapy for the management of upper gastrointestinal bleeding that is refractory to endoscopic hemostasis.Advances in catheter-based techniques and newer embolic agents, as well as recognition of the effectiveness of minimally invasive treatment options,have expanded the role of interventional radiology in the management of hemorrhage for a variety of indications,such as peptic ulcerbleeding,malignant disease,hemorrhagic Dieulafoy lesions and iatrogenic or trauma bleeding.Transcatheter interventions include the following:selective embolization of the feeding artery,sandwich coil occlusion of the gastroduodenal artery,blind or empiric embolization of the supposed bleeding vessel based on endoscopic findings and coil pseudoaneurysm or aneurysm embolization by three-dimensional sac packing with preservation of the parent artery.Transcatheter embolization is a fast,safe and effective,minimally invasive alternative to surgery when endoscopic treatment fails to control bleeding from the upper gastrointestinal tract.This article reviews the various transcatheter endovascular techniques and devices that are used in a variety of clinical scenarios for the management of hemorrhagic gastrointestinal emergencies.
基金supported in whole or part by grants from the National Institutes of Health (CA154737, CA199092, HL122471, HL112518, HL113392, and HHSN26820140042C for Gregory M.Lanza AR067491, DK102691, and HL073646 for Samuel A.Wickline)We appreciate the further support provided the Barnes-Jewish Research Foundation
文摘The research roots of 19fluorine （19F） magnetic resonance imaging （MRI） date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, ~gF/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of ~gF into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents.
基金support by the National Key Technologies R&D Program (No. 2016YFC0207103)Koninklijke Philips N.V.Brainbridge Cooperation Agreement (Grant Number BB3-2016-01)
文摘The primary emphasis of this research was to investigate the foundations of phthalate（PAEs） pollutant source researches and then firstly confirmed the concept of the coefficient of volatile strength, namely phthalate total content in per unit mass and unit surface area of pollutant sources. Through surveying and evaluating the coefficient of volatile strength of PAEs from typical plastic products, this research carried out reasonable classification of PAEs pollutant sources into three categories and then investigated the relationship amongst the coefficient of volatile strength as well as other environmental factors and the concentration level of total PAEs in indoor air measured in environment chambers.Research obtained phthalate concentration results under different temperature, humidity,the coefficient of volatile strength and the closed time through the chamber experiment. In addition, this study further explored the correlation and ratio of influencing factors that affect the concentration level of total PAEs in environment chambers, including environmental factors, the coefficient of volatile strengths of PAEs and contents of total PAEs in plastic products. The research created an improved database system of phthalate the coefficient of volatile strengths of each type of plastic goods, and tentatively revealed that the volatile patterns of PAEs from different typical plastic goods, finally confirmed that the coefficient of volatile strengths of PAEs is a major factor that affects the indoor air total PAEs concentration, which laid a solid foundation for further establishing the volatile equation of PAEs from plastic products.
基金partially supported by National Key Project of China under Grants No. 2013ZX03001007-004National Natural Science Foundation of China under Grants No. 61102052,61325012,61271219,91438115 and 61221001
文摘Switch policy is essential for small cells to properly serve variable number of users in an energy efficient way.However,frequently switching small cell base stations(SBSs) may increase the network operating cost,especially when there is an nonnegligible start-up energy cost.To this end,by observing the variety of user number,we focus on the design of a switch policy which minimize the cumulative energy consumption.A given user transmission rate is guaranteed and the capability of SBSs are limited as well.According to the knowledge on user number variety,we classify the energy consumption problem into two cases.In complete information case,to minimize the cumulative energy consumption,an offline solution is proposed according to critical segments.A heuristic algorithm for incomplete information case(HAIIC) is proposed by tracking the difference of cumulative energy consumption.The upper bound of the Energy Consumption Ratio(ECR) for HAIIC is derived as well.In addition,a practical Q-learning based probabilistic policy is proposed.Simulation results show that the proposed HAIIC algorithm is able to save energy efficiently.
文摘AIMTo investigate the accuracy of a rotational C-arm CT-based 3D heart model to predict an optimal C-arm configuration during transcatheter aortic valve replacement (TAVR).METHODSRotational C-arm CT (RCT) under rapid ventricular pacing was performed in 57 consecutive patients with severe aortic stenosis as part of the pre-procedural cardiac catheterization. With prototype software each RCT data set was segmented using a 3D heart model. From that the line of perpendicularity curve was obtained that generates a perpendicular view of the aortic annulus according to the right-cusp rule. To evaluate the accuracy of a model-based overlay we compared model- and expert-derived aortic root diameters.RESULTSFor all 57 patients in the RCT cohort diameter measurements were obtained from two independent operators and were compared to the model-based measurements. The inter-observer variability was measured to be in the range of 0°-12.96° of angular C-arm displacement for two independent operators. The model-to-operator agreement was 0°-13.82°. The model-based and expert measurements of aortic root diameters evaluated at the aortic annulus (r = 0.79, P < 0.01), the aortic sinus (r = 0.93, P < 0.01) and the sino-tubular junction (r = 0.92, P < 0.01) correlated on a high level and the Bland-Altman analysis showed good agreement. The interobserver measurements did not show a significant bias.CONCLUSIONAutomatic segmentation of the aortic root using an anatomical model can accurately predict an optimal C-arm configuration, potentially simplifying current clinical workflows before and during TAVR.
文摘Background:In congenital heart disease(CHD)patients,detailed three-dimensional anatomy depiction plays a pivotal role for diagnosis and therapeutical decision making.Hence,the present study investigated the applicability of an advanced cardiovascular magnetic resonance(CMR)whole heart imaging approach utilizing nonselective excitation and compressed sensing for anatomical assessment and interventional guidance of CHD patients in comparison to conventional dynamic CMR angiography.Methods:86 consecutive pediatric patients and adults with congenital heart disease(age,1 to 74 years;mean,35 years)underwent CMR imaging including a freebreathing,ECG-triggered 3D nonselective SSFP whole heart acquisition using compressed SENSE(nsWHcs).Anatomical assessability and signal intensity ratio(SIR)measurements were compared with conventional dynamic 3D-/4D-MR angiography.Results:The most frequent diagnoses were partial anomalous pulmonary venous drainage(17/86,20%),transposition of the great arteries(15/86,17%),tetralogy of Fallot(12/86,14%),and a single ventricle(7/86,8%).Image quality of nsWHcs was rated as excellent/good in 98%of patients.nsWHcs resulted in a reliable depiction of all large thoracic vessels(anatomic assessability,99%–100%)and the proximal segments of coronary arteries and coronary sinus(>90%).nsWHcs achieved a homogenously distributed SIR in all cardiac cavities and thoracic vessels without a significant difference between pulmonary and systemic circulation(10.9±3.5 and 10.6±3.4;p=0.15),while 3D angiography showed significantly increased SIR for targeted vs.non-targeted circulation(PA-angiography,15.2±8.1 vs.5.8±3.6,p<0.001;PV-angiography,7.0±3.9 vs.17.3±6.8,p<0.001).Conclusions:The proposed nsWHcs imaging approach provided a consistently high image quality and a homogeneous signal intensity distribution within the pulmonary and systemic circulation in pediatric patients and adults with a wide spectrum of congenital heart diseases.nsWHcs enabled detailed anatomical assessment and three-dimensional reconstruction of all cardiac cavities and large thoracic vessels and can be regarded particularly useful for preprocedural planning and interventional guidance in CHD patients.
文摘Cerebral arteriovenous malformations (AVMs) are a type of vascular anomaly consisting of large intertwined vascular growth (Nidus) that is prone to serious hemorrhaging and can result in patient death if left untreated. Intervention through surgical clipping of feeding and draining vessels to the Nidus is a common treatment. However, identification of which vessels to clip is challenging even to experienced surgeons aided by conventional image guidance systems. The lumped modeling for the Cerebral Arteriovenous Malformation (CAVM) hemodynamic analysis is of high importance in clinical world. As part of the treatment planning for CAVM, it is difficult for doctors to assess the NIDUS part, which may get rupture while inserting catheter. In this paper, we have proposed a non-invasive method for assessing the hemodynamic condition of AVM. The measurement of flow and pressure without intervention along the vessel is a big challenge due to occlusion, bending and thinning of the vessel in Arteriovenous Malformation patients. In this paper, we analyzed a lumped model for the vascular malformation using various imaging multi-modalities that help to analyze CAVM Structures.
文摘Aim: Neurovascular abnormalities are extremely complex, due to the multitude of factors acting simultaneously on cerebral hemodynamics. Cerebral Arteriovenous Malformation (CAVM) hemo-dynamic in one of the vascular abnormality condition results changes in the vessels structures and hemodynamics in blood vessels. The challenge is segmenting accurate vessel region to measure hemodynamics of CAVM patients. The clinical procedure is in-vivo method to measure hemodynamics. The catheter-based procedure is difficult, as it is sometimes difficult to reach vessels sub-structures. Methods: In this paper, we have proposed adaptive vessel segmentation based on threshold technique for CAVM patients. We have compared different adaptive methods for vessel segmentation of CAVM structures. The sub-structures are modeled using lumped model to measure hemodynamics non-invasively. Results: Twenty-three CAVM patients with 150 different vessel locations of DSA datasets were studied as part of the adaptive segmentation. 30 simulated data has been evaluated for more than 150 vessels locations for sub-segmentation of vessels. The segmentation results are evaluated with accuracy of 93%. The computed p-value is smaller than the significance level 0.05. Conclusion: The adaptive segmentation using threshold based produces accurate vessel segmentation, results in better accuracy of hemodynamic measurements for DSA images for CAVM patients. The proposed adaptive segmentation helps clinicians to measure hemodynamic non-invasively for the segmented sub-structures of vessels.
文摘Purpose: To generate parametric images of tumor hypoxia in a tumor-bearing rat model using voxel-based compartmental analysis of dynamic fluorine-18 labeled misonidazole (18F-FMISO) microPET? images, and to compare the parametric images thus derived with static “late” 18F-FMISO microPET? images for the detection of tumor hypoxia. Materials and Methods: Nude rats bearing HT-29 colorectal carcinoma xenografts (≈1.5 - 2 cm in diameter) in the right hind limb were positioned in a custom-fabricated, animal-specific foam mold. Animals were injected via the tail vein with ≈55.5 MBq 18F-FMISO and continuously imaged for either 60 or 120 minutes, with additional late static images up to 3 hour post-injection. The raw list-mode data was reconstructed into 37 - 64 frames with earlier frames of shorter time durations (12 - 15 seconds) and later frames of longer durations (up to 300 seconds). Time activity curves (TACs) were generated over regions encompassing the tumor as well as an artery, the latter for use as an input function. A beta version of a compartmental modeling package (BioGuide?, Philips Healthcare) was used to generate parametric images of k3 and Ki, rate constants of entrapment and flux of 18F-FMISO, respectively. Results: Data for 7 HT-29 tumor xenografts were presented, 6 of which yielded clear areas of tumor hypoxia as defined by Ki/k3 maps. Importantly, intratumoral foci with high 18F-FMISO uptakes on the late images did not always exhibit high Ki/k3 values and may there- fore represent false-positives for radiobiologically significant hypoxia. Conclusions: This study attempts to quantify tumor hypoxia using compartmental analysis of dynamic 18F-FMISO PET images in rodent xenograft tumor models. The results demonstrate feasibility of the approach in small-animal imaging studies, and provide evidence for the possible unreliability of late-time static imaging of 18F-FMISO PET in identifying tumor hypoxia.
基金supported by a research grant of Philips "Brain-Bridge Plan"
文摘To brew tea correctly is very important to absorb the tea nutrition for people.The dynamic changes of the main compositions in brewing Pu'erh tea processing with different conditions were studied.Three different temperatures and eight times were designed to study the effects on the tea infusion quality.The index t0.5min(50%concentration of compounds in tea infusion) was used to evaluate the extract speed of compound in this experiment.The results showed that caffeine solubility speed at 80℃ was the highest to compare with tea polyphenols,amino acid,caffeine,soluble sugar,theaflavins and theabrownine,t0.5min of caffeine was 4.8 min,amino acid 10.3min was the second,the third one was tea polyphenols,soluble sugar was the lowest.We also found in different infusion temperature the t0.5min of compounds was distinguishing.With increasing the temperature all t0.5min of six compounds were shorter.However,the change regulations of t0.5min for all compounds in 90℃ and 100℃ were similar to in 80℃.Total quality score(TQS) were applied to evaluate the quality of tea infusion.The results found the TQS score of infusion was higher with the temperature rising,and the temperature to brew best quality infusion was 100℃ for 4-5min.According to the multiple regression analysis between sensory assessments and chemical components of Pu'erh tea we suggested the TQS was mainly affected by theaflavins,amino acid,soluble sugar and theabrowine four factors in 100℃.
基金supported by a research grant of Philips "Brain-Bridge Plan"
文摘The recent research achievements about the mechanisms of beneficial health effects of tea polyphenols and the epidemiological investigation on anti-cancer,anti-cardiovascular diseases,and anti-obesity through tea consumption were reviewed.It is proved that reactive oxygen species is the main reason to induce cell mutation,DNA damage,obesity,high blood pressure and many kinds of cancers.Tea catechins and theaflavins have excellent bioactivity on scavenging ROS due to their characteristic structure feature of phenolic hydroxyl group,which means drinking tea could prevent diseases.Epidemidogical investigations also showed that tea consumption could reduce the risk of lung cancer,gastric cancer,bladder cancer,and so on.However,the frequency of tea drinking or tea consumption amounts significantly affected the prevention efficiency.The epidemiologic investigations also find that drink green tea,especial black tea is useful to modify the cardiovascular diseases.In vivo and vitro tests showed that tea supplement could moderate the metabolism of blood lipid and prevent obesity.These indicated that tea and tea extracts might reduce the risk of many diseases.
基金partly supported by NSFC Grant (No.61672342,No.61671478,No.61572319,No.61532012,No.61325012,No.91438115)Science & Technology Innovation Program of Shanghai Grant (No.17511105103)+1 种基金National Key Scientif ic Research Project under Grant (No.2017YFB0803200)Natural Science Foundation of Shanghai under Grant (No.14ZR1427700)
文摘Mobile broadcasting services provided by converged networks do aid in satisfying users' demands for popular multimedia content while unicasting services offer personalized experiences for users.We analyze hybrid broadcasting unicasting framework from the perspective of network economics,where content provider(CP) figures out the cooperation of broadcasting and unicasting services providers,as long as their pricing strategies.To this end,a contract-based content delivery scheme is proposed.The profit of CP depends on users' preference and satisfaction for unicasting and broadcasting transmission.CP provides different users with distinctive data packages.The intent is to maximize its own profit.By classifying users into different types,the optimal contract in close form is derived.Numerical results show that the proposed optimal contract is able to generate incentive for users to employ broadcasting transmission,which further benefits both the CP and users.
文摘In many medical fields,spatial localization of devices is of paramount importance to e.g.deliver treatments correctly or to perform accurate diagnostic evaluations.Among the different technologies available,optical localization in the visible band of the spectrum offers many advantages:minimum interference with other instruments,flexibility in position of the devices used and extra features such as patient/operator surface tracking or vital signs monitoring.Its application in the domain of radiotherapy is novel,and potentially very beneficial.In this work we introduced a workflow to test the reliability of one of these systems,developed in house,to localize an ultrasound transducer for ultrasound guided radiation therapy(USg RT).Accuracy,precision,latency,sensitive volume and sensitivity to light intensity were evaluated.The workflow we proposed allowed us to establish that,while all the clinically relevant parameters of the system are acceptable,accuracy in locating the transducer could be as intended purpose of the system.
基金This work is part of the research program of the Foundation for Fundamental Research on Matter(FOM),which is financially supported by the Netherlands Organization for Fundamental Research(NWO)It is also part of an industrial partnership program between Philips and FOM.It is supported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-statelighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability oflight emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, thefundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonicstructures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminumnanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able tomold the spectral and angular distribution of the emission with unprecedented precision.
基金supported by the National Natural Science Foundation of China (81401932)the Beijing Natural Science Foundation (7154246)
文摘In this study, we aimed to investigate the functional network changes that occur in patients with lower back pain(LBP). We also investigated the link between LBP and the small-world properties of functional networks within the brain. Functional MRI(fMRI) was performed on 20 individuals with LBP and 17 age and gender-matched normal controls during the resting state. The severity of the pain in the individuals with LBP ranged from 5 to 8 on a 0–10 scale, with 0 indicating no pain. Network-based statistics were performed to investigate the differences between the brain networks of individuals with LBP and those of normal controls. Several small-world parameters of brain networks were calculated, including the clustering coefficient, characteristic path length, local efficiency, and global efficiency. These criteria reflect the overall network efficiency. The brain networks in the individuals with LBP due to herniation of a lumbar disc demonstrated a significantly longer characteristic path length as well as a lower clustering coefficient, global efficiency, and local efficiency compared to those in control subjects. We found that LBP patients tended to have unstable and inefficient brain networks when compared with healthy controls. In addition, LBP individuals showed significantly decreased functional connectivity in the anterior cingulate cortex, middle cingulate cortex, post cingulate cortex, inferior frontal gyrus, middle temporal gyrus, occipital gyrus, postcentral gyrus, precentral gyrus, supplementary motor area, thalamus, fusiform, caudate, and cerebellum. We believe that these regions may be involved in the pathophysiology of lower back pain.
基金supported by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek(NWO)through the project LEDMAP of the Technology Foundation STWthrough the Industrial Partnership Program Nanophotonics for Solid State Lighting between Philips and the Foundation for Fundamental Research on Matter FOMsupported by NanoNextNL of the Government of the Netherlands and 130 partners.
文摘Light-emitting diodes(LEDs)are driving a shift toward energy-efficient illumination.Nonetheless,modifying the emission intensities,colors and directionalities of LEDs in specific ways remains a challenge often tackled by incorporating secondary optical components.Metallic nanostructures supporting plasmonic resonances are an interesting alternative to this approach due to their strong light–matter interaction,which facilitates control over light emission without requiring external secondary optical components.This review discusses new methods that enhance the efficiencies of LEDs using nanostructured metals.This is an emerging field that incorporates physics,materials science,device technology and industry.First,we provide a general overview of state-of-the-art LED lighting,discussing the main characteristics required of both quantum wells and color converters to efficiently generate white light.Then,we discuss the main challenges in this field as well as the potential of metallic nanostructures to circumvent them.We review several of the most relevant demonstrations of LEDs in combination with metallic nanostructures,which have resulted in light-emitting devices with improved performance.We also highlight a few recent studies in applied plasmonics that,although exploratory and eminently fundamental,may lead to new solutions in illumination.
文摘Background In recent years,computers have been intensively used at home.In contrast to paper-based books and documents,computer screen is self-illuminated with larger screen-background luminance difference,which greatly induces visual discomfort.To compensate for that,one effective solution is to offer an additional background luminance.In this study,we investigated whether and to what extent additional background lighting is needed in looking at a computer display comfortably.Methods In this study,60 healthy children aged from 9 to 12 years and 58 adults aged from 21 to 39 years participated in the experiments.They were asked to choose their most preferred background luminance intensities at three screen luminance levels.The data were analyzed by Matlab （R2012b） and SPSS 20.0.Results Both children and adult participants selected a non-dark background as their comfortable lighting condition when watching a computer display （children：t （59）=22.0,P 〈0.01,adults：t （57）=15.5,P 〈0.01）.Comparatively,children preferred brighter background in general （F （1,116）=7.0,P 〈0.01）.More importantly,participants＇ preferred background luminance levels were linearly correlated with screen luminance intensities （children：slope=0.97,R2=0.98; adults：slope=0.38,R2=1.00）.Conclusion These results indicate that varying background luminance to maintain screen-background luminance ratio is beneficial to human visual comfort.
