BACKGROUND Patients who undergo orthopedic procedures are often given excess opioid medication.Understanding the relationship between pain and opioid consumption following total hip arthroplasty(THA)is key to creating...BACKGROUND Patients who undergo orthopedic procedures are often given excess opioid medication.Understanding the relationship between pain and opioid consumption following total hip arthroplasty(THA)is key to creating safe and effective opioid prescribing guidelines.AIM To evaluate the association between the quantity of opioid consumption in relation to pain scores both pre-and postoperatively in patients undergoing primary THA.METHODS We retrospectively reviewed patients who underwent primary THA from November 2018-May 2019 and answered both the visual analog scale(VAS)pain and opioid medication questionnaires pre-and postoperatively.Both surveys were delivered daily for 7-days before surgery through the first 30 postoperative days.Survey results were divided into preoperative,postoperative days 1-7,postoperative days 8-14,and postoperative days 15-30 for analysis.Mean opioid pill consumption and VAS pain scores in each time period were determined and compared to patients’preoperative status using hierarchical Poisson and linear regressions,respectively.RESULTS There were 105 patients included.Mean VAS pain scores were the highest preoperatively 7.41±1.72.However,VAS pain scores significantly declined in each successive postoperative category compared to preoperative scores:postoperative day 1-7(5.07±1.79;P<0.001),postoperative day 8-14(3.60±1.64;P<0.001),and postoperative day 15-30(3.15±1.63;P<0.001).Mean opioid pill consumption preoperatively was 0.68±1.29 pills.Compared to preoperative opioid consumption,opioid use was significantly greater between postoperative days 1-7(1.51±1.58;P=0.001)and postoperative days 8-14(1.00±1.27;P=0.043).Opioid consumption declined below preoperative levels between postoperative days 15-30(0.35±0.72;P=0.160)which correlates with a VAS pain score of 3.15.CONCLUSION All patients experienced significant benefit and pain relief from having undergone THA.Average postoperative opioid consumption decreased below preoperative consumption between postoperative days 15-30,which was associated with a VAS pain score of 3.15.These results can be used to appropriately guide opioid prescribing practices and set patient expectations regarding pain management following THA.展开更多
Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses...Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses in healthy, moderate caffeine-consuming volunteers through the use of population pharmacokinetic-pharmacodynamic (PK-PD) modeling. Twelve subjects were recruited for a three-period cross-over study which utilized caffeine containing beverages. Each visit included 8-hour blood plasma and VAS response collection for PK and PD assessment respectively. The VAS used in the study, also called the caffeine analog scale, has been previously validated for caffeine. Population PK-PD modeling was conducted with NONMEM 7.2. Simultaneous and sequential modeling of PK-PD was attempted. Final model selection was based on parameter estimate precision, diagnostic plots, and visual predictive check (VPC) plots. Results showed that a one-compartment open model with first-order absorption and elimination best described the pharmacokinetics of caffeine. Sequential PK-PD modeling was successful and an effect compartment model with linear slope and baseline parameter best described caffeine pharmacodynamics. Diagnostic plots showed no major bias and VPC plots showed agreement between observations and predictions. The model was able to link VAS responses to caffeine concentration in healthy volunteers and may be useful in clinical trial simulations and design.展开更多
Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate ...Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate whether a visual analogue scale (VAS) could be linear with the LSAS and substitute for the LSAS, 2) to relate such a VAS instrument to patient demographics. Methods: Fifty SAD patients were assessed using the LSAS and VAS instruments completed by both patients and doctors at the same session. We then drew distributions and calculated the Spearman’s ρ and κ coefficient values (divided at the median for each scale) between patient and doctor assessments. Next, each pair among the scores for the LSAS, the patient VAS and the doctor VAS was compared using Wilcoxon rank sum tests according to patient life profile data. Results: Scatter plots of pairs of scores were obtained. Spearman’s ρ was 0.661 between the LSAS and the patient VAS, 0.461 between the LSAS and the doctor VAS, and 0.494 between VAS scores of patients and doctors. The κ coefficients were 0.501 between the LSAS and patient VAS, 0.251 between the LSAS and doctor VAS, and 0.425 between patient VAS and doctor VAS (for all six, p < 0.001). The Wilcoxon rank sum tests indicated a significant difference between the groups with/ without “employment” (LSAS, patient/doctor VAS), with/without “graduation from junior college/university” (doctor VAS) (p < 0.05) and with/without marital history (the age of first consultation) (p < 0.01). Conclusions: A patient VAS may substitute for the LSAS and offer the versatility necessary to capture patient states and life profiles.展开更多
The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestru...The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestructive manner. To eliminate the possibility of false images being produced because of X-ray broadening effects, we developed a visualization method by arranging the brightness distribution of all phases involved. Water flooding experiments were conducted using oil-wet and water-wet porous media. The water phase was injected upward into packed glass beads containing an oil phase, and the process was scanned every minute until steady state was reached. Using this scheme, real-time, the water invasion pattern and oil trapping process in clusters of pores and individual pores can be observed clearly. By eliminating false images, the boundary of each phase could be identified with high precision, even in a single pore. Porelevel phenomena, including snap off (which has never before been captured in a real 3D porous medium), piston-like displacement, and the curvature of the interface, were also observed. Direct measurement of the pore throat radius and the contact angle between the wetting and nonwetting phases gave an approximation of the capillary pressure during the piston-like displacement and snap-off processes.展开更多
In aerial robots＇ visual navigation, it is essential yet very difficult to detect the attitude and position of the robots operated in real time. By introducing a new parametric model, the problem can be reduced from ...In aerial robots＇ visual navigation, it is essential yet very difficult to detect the attitude and position of the robots operated in real time. By introducing a new parametric model, the problem can be reduced from almost unmanageable to be partly solved, though not fully, as per the requirement. In this parametric approach, a multi-scale least square method is formulated first. By propagating as well as improving the parameters down from layer to layer of the image pyramid, a new global feature line can then be detected to parameterize the attitude of the robots. Furthermore, this approach paves the way for segmenting the image into distinct parts, which can be realized by deploying a Bayesian classifier on the picture cell level. Comparison with the Hough transform based method in terms of robustness and precision shows that this multi-scale least square algorithm is considerably more robust to noises. Some discussions are also given.展开更多
Monocular visual odometry (VO) is the process of determining a user’s trajectory through a series of consecutive images taken by a single camera. A major problem that affects the accuracy of monocular visual odometry...Monocular visual odometry (VO) is the process of determining a user’s trajectory through a series of consecutive images taken by a single camera. A major problem that affects the accuracy of monocular visual odometry, however, is the scale ambiguity. This research proposes an innovative augmentation technique, which resolves the scale ambiguity problem of monocular visual odometry. The proposed technique augments the camera images with range measurements taken by an ultra-low-cost laser device known as the Spike. The size of the Spike laser rangefinder is small and can be mounted on a smartphone. Two datasets were collected along precisely surveyed tracks, both outdoor and indoor, to assess the effectiveness of the proposed technique. The coordinates of both tracks were determined using a total station to serve as a ground truth. In order to calibrate the smartphone’s camera, seven images of a checkerboard were taken from different positions and angles and then processed using a MATLAB-based camera calibration toolbox. Subsequently, the speeded-up robust features (SURF) method was used for image feature detection and matching. The random sample consensus (RANSAC) algorithm was then used to remove the outliers in the matched points between the sequential images. The relative orientation and translation between the frames were computed and then scaled using the spike measurements in order to obtain the scaled trajectory. Subsequently, the obtained scaled trajectory was used to construct the surrounding scene using the structure from motion (SfM) technique. Finally, both of the computed camera trajectory and the constructed scene were compared with ground truth. It is shown that the proposed technique allows for achieving centimeter-level accuracy in monocular VO scale recovery, which in turn leads to an enhanced mapping accuracy.展开更多
Visual saliency is an important cue in human visual system to identify salient region in the image;it can be useful in many applications including image retrieval,object recognition,image segmentation,etc.Image contra...Visual saliency is an important cue in human visual system to identify salient region in the image;it can be useful in many applications including image retrieval,object recognition,image segmentation,etc.Image contrast has been used as an effective feature to detect visual salient region.However,the conventional contrast measures either in spectral domain or in spatial domain fail to give sufficient consideration towards the local and global characteristics of the image.This paper presents a visual saliency detection algorithm based on a novel contrast measurement.This measurement extracts the spectral information of image block using the 2D discrete Fourier transform(DFT),and combines with the total variation(TV)of image block in spatial domain.The proposed algorithm is used to perform salient region detection in the image,and compared with state-of-the-art algorithms.The experimental results from the MSRA dataset validate the effectiveness of the proposed algorithm.展开更多
Visual fixation is an item in the visual function subscale of the Coma Recovery Scale-Revised （CRS-R）. Sometimes clinicians using the behavioral scales find it difficult to detect because of the motor impairment in ...Visual fixation is an item in the visual function subscale of the Coma Recovery Scale-Revised （CRS-R）. Sometimes clinicians using the behavioral scales find it difficult to detect because of the motor impairment in patients with disorders of consciousness （DOCs）. Brain- computer interface （BCI） can be used to improve clinical assessment because it directly detects the brain response to an external stimulus in the absence of behavioral expres- sion. In this study, we designed a BCI system to assist the visual fixation assessment of DOC patients. The results from 15 patients indicated that three showed visual fixation in both CRS-R and BCI assessments and one did not show such behavior in the CRS-R assessment but achieved significant online accuracy in the BCI assessment. The results revealed that electroencephalography-based BCI can detect the brain response for visual fixation. Therefore, the proposed BCI may provide a promising method for assisting behavioral assessment using the CRS-R.展开更多
文摘BACKGROUND Patients who undergo orthopedic procedures are often given excess opioid medication.Understanding the relationship between pain and opioid consumption following total hip arthroplasty(THA)is key to creating safe and effective opioid prescribing guidelines.AIM To evaluate the association between the quantity of opioid consumption in relation to pain scores both pre-and postoperatively in patients undergoing primary THA.METHODS We retrospectively reviewed patients who underwent primary THA from November 2018-May 2019 and answered both the visual analog scale(VAS)pain and opioid medication questionnaires pre-and postoperatively.Both surveys were delivered daily for 7-days before surgery through the first 30 postoperative days.Survey results were divided into preoperative,postoperative days 1-7,postoperative days 8-14,and postoperative days 15-30 for analysis.Mean opioid pill consumption and VAS pain scores in each time period were determined and compared to patients’preoperative status using hierarchical Poisson and linear regressions,respectively.RESULTS There were 105 patients included.Mean VAS pain scores were the highest preoperatively 7.41±1.72.However,VAS pain scores significantly declined in each successive postoperative category compared to preoperative scores:postoperative day 1-7(5.07±1.79;P<0.001),postoperative day 8-14(3.60±1.64;P<0.001),and postoperative day 15-30(3.15±1.63;P<0.001).Mean opioid pill consumption preoperatively was 0.68±1.29 pills.Compared to preoperative opioid consumption,opioid use was significantly greater between postoperative days 1-7(1.51±1.58;P=0.001)and postoperative days 8-14(1.00±1.27;P=0.043).Opioid consumption declined below preoperative levels between postoperative days 15-30(0.35±0.72;P=0.160)which correlates with a VAS pain score of 3.15.CONCLUSION All patients experienced significant benefit and pain relief from having undergone THA.Average postoperative opioid consumption decreased below preoperative consumption between postoperative days 15-30,which was associated with a VAS pain score of 3.15.These results can be used to appropriately guide opioid prescribing practices and set patient expectations regarding pain management following THA.
文摘Caffeine is a commonly ingested psychoactive substance which affects alertness and cognition. A clinical study was conducted to determine the effect of orally ingested caffeine on visual analogue scale (VAS) responses in healthy, moderate caffeine-consuming volunteers through the use of population pharmacokinetic-pharmacodynamic (PK-PD) modeling. Twelve subjects were recruited for a three-period cross-over study which utilized caffeine containing beverages. Each visit included 8-hour blood plasma and VAS response collection for PK and PD assessment respectively. The VAS used in the study, also called the caffeine analog scale, has been previously validated for caffeine. Population PK-PD modeling was conducted with NONMEM 7.2. Simultaneous and sequential modeling of PK-PD was attempted. Final model selection was based on parameter estimate precision, diagnostic plots, and visual predictive check (VPC) plots. Results showed that a one-compartment open model with first-order absorption and elimination best described the pharmacokinetics of caffeine. Sequential PK-PD modeling was successful and an effect compartment model with linear slope and baseline parameter best described caffeine pharmacodynamics. Diagnostic plots showed no major bias and VPC plots showed agreement between observations and predictions. The model was able to link VAS responses to caffeine concentration in healthy volunteers and may be useful in clinical trial simulations and design.
文摘Introduction: The Liebowitz Social Anxiety Scale (LSAS), used to assess the severity of social anxiety disorder (SAD), requires considerable effort and time to complete. The aims of this study were: 1) to investigate whether a visual analogue scale (VAS) could be linear with the LSAS and substitute for the LSAS, 2) to relate such a VAS instrument to patient demographics. Methods: Fifty SAD patients were assessed using the LSAS and VAS instruments completed by both patients and doctors at the same session. We then drew distributions and calculated the Spearman’s ρ and κ coefficient values (divided at the median for each scale) between patient and doctor assessments. Next, each pair among the scores for the LSAS, the patient VAS and the doctor VAS was compared using Wilcoxon rank sum tests according to patient life profile data. Results: Scatter plots of pairs of scores were obtained. Spearman’s ρ was 0.661 between the LSAS and the patient VAS, 0.461 between the LSAS and the doctor VAS, and 0.494 between VAS scores of patients and doctors. The κ coefficients were 0.501 between the LSAS and patient VAS, 0.251 between the LSAS and doctor VAS, and 0.425 between patient VAS and doctor VAS (for all six, p < 0.001). The Wilcoxon rank sum tests indicated a significant difference between the groups with/ without “employment” (LSAS, patient/doctor VAS), with/without “graduation from junior college/university” (doctor VAS) (p < 0.05) and with/without marital history (the age of first consultation) (p < 0.01). Conclusions: A patient VAS may substitute for the LSAS and offer the versatility necessary to capture patient states and life profiles.
文摘The penetration of water during water flooding has been observed over many years using several methods. A microfocused X-ray computed tomography scanner can be used to directly observe 3D water flooding in a nondestructive manner. To eliminate the possibility of false images being produced because of X-ray broadening effects, we developed a visualization method by arranging the brightness distribution of all phases involved. Water flooding experiments were conducted using oil-wet and water-wet porous media. The water phase was injected upward into packed glass beads containing an oil phase, and the process was scanned every minute until steady state was reached. Using this scheme, real-time, the water invasion pattern and oil trapping process in clusters of pores and individual pores can be observed clearly. By eliminating false images, the boundary of each phase could be identified with high precision, even in a single pore. Porelevel phenomena, including snap off (which has never before been captured in a real 3D porous medium), piston-like displacement, and the curvature of the interface, were also observed. Direct measurement of the pore throat radius and the contact angle between the wetting and nonwetting phases gave an approximation of the capillary pressure during the piston-like displacement and snap-off processes.
文摘In aerial robots＇ visual navigation, it is essential yet very difficult to detect the attitude and position of the robots operated in real time. By introducing a new parametric model, the problem can be reduced from almost unmanageable to be partly solved, though not fully, as per the requirement. In this parametric approach, a multi-scale least square method is formulated first. By propagating as well as improving the parameters down from layer to layer of the image pyramid, a new global feature line can then be detected to parameterize the attitude of the robots. Furthermore, this approach paves the way for segmenting the image into distinct parts, which can be realized by deploying a Bayesian classifier on the picture cell level. Comparison with the Hough transform based method in terms of robustness and precision shows that this multi-scale least square algorithm is considerably more robust to noises. Some discussions are also given.
文摘Monocular visual odometry (VO) is the process of determining a user’s trajectory through a series of consecutive images taken by a single camera. A major problem that affects the accuracy of monocular visual odometry, however, is the scale ambiguity. This research proposes an innovative augmentation technique, which resolves the scale ambiguity problem of monocular visual odometry. The proposed technique augments the camera images with range measurements taken by an ultra-low-cost laser device known as the Spike. The size of the Spike laser rangefinder is small and can be mounted on a smartphone. Two datasets were collected along precisely surveyed tracks, both outdoor and indoor, to assess the effectiveness of the proposed technique. The coordinates of both tracks were determined using a total station to serve as a ground truth. In order to calibrate the smartphone’s camera, seven images of a checkerboard were taken from different positions and angles and then processed using a MATLAB-based camera calibration toolbox. Subsequently, the speeded-up robust features (SURF) method was used for image feature detection and matching. The random sample consensus (RANSAC) algorithm was then used to remove the outliers in the matched points between the sequential images. The relative orientation and translation between the frames were computed and then scaled using the spike measurements in order to obtain the scaled trajectory. Subsequently, the obtained scaled trajectory was used to construct the surrounding scene using the structure from motion (SfM) technique. Finally, both of the computed camera trajectory and the constructed scene were compared with ground truth. It is shown that the proposed technique allows for achieving centimeter-level accuracy in monocular VO scale recovery, which in turn leads to an enhanced mapping accuracy.
基金the Natural Science Foundation of Hubei Province(No.2014CFB247)the National Natural Science Foundation of China(Nos.61440016,61273225,61273303 and 31201121)the Project of the Key Laboratory for Metallurgical Equipment and Control of Ministry of Education(No.2013B08)
文摘Visual saliency is an important cue in human visual system to identify salient region in the image;it can be useful in many applications including image retrieval,object recognition,image segmentation,etc.Image contrast has been used as an effective feature to detect visual salient region.However,the conventional contrast measures either in spectral domain or in spatial domain fail to give sufficient consideration towards the local and global characteristics of the image.This paper presents a visual saliency detection algorithm based on a novel contrast measurement.This measurement extracts the spectral information of image block using the 2D discrete Fourier transform(DFT),and combines with the total variation(TV)of image block in spatial domain.The proposed algorithm is used to perform salient region detection in the image,and compared with state-of-the-art algorithms.The experimental results from the MSRA dataset validate the effectiveness of the proposed algorithm.
基金supported by the National Key Research and Development Program of China (2017YFB1002505)the National Natural Science Foundation of China (61633010, 91420302, and 61503143)+1 种基金the Natural Science Foundation of Guangdong Province, China (2014A030312005 and 2014A030310244)the Pearl River S&T Nova Program of Guangzhou Municipality, China (201710010038)
文摘Visual fixation is an item in the visual function subscale of the Coma Recovery Scale-Revised （CRS-R）. Sometimes clinicians using the behavioral scales find it difficult to detect because of the motor impairment in patients with disorders of consciousness （DOCs）. Brain- computer interface （BCI） can be used to improve clinical assessment because it directly detects the brain response to an external stimulus in the absence of behavioral expres- sion. In this study, we designed a BCI system to assist the visual fixation assessment of DOC patients. The results from 15 patients indicated that three showed visual fixation in both CRS-R and BCI assessments and one did not show such behavior in the CRS-R assessment but achieved significant online accuracy in the BCI assessment. The results revealed that electroencephalography-based BCI can detect the brain response for visual fixation. Therefore, the proposed BCI may provide a promising method for assisting behavioral assessment using the CRS-R.
