Magnetic resonance imaging (MRI) is an important medical imaging method, whose major limitation is its long scan time due to the imaging mechanism, increasing patients' cost and waiting time for the examination. Currently, parallel imaging (PI) and compress sensing (CS) together with other reconstruction technologies have been proposed to accelerate image acquisition. However, the image quality of PI and CS depends on the image reconstruction algorithms, which is far from satisfying in respect to both the image quality and the reconstruction speed. In recent years, image reconstruction based on generative adversarial network (GAN) has become a research hotspot in the field of magnetic resonance imaging because of its excellent performance. In this review, we summarized the recent development of application of GAN in MRI reconstruction in both single- and multi-modality acceleration, hoping to provide a useful reference for interested researchers. In addition, we analyzed the characteristics and limitations of existing technologies and forecasted some development trends in this field.
Humans ; Acceleration ; Algorithms ; Magnetic Resonance Imaging ; Technology

A protective device was designed that can be worn on the elderly, which consists of protective airbag, control box and protective mechanism. The combined acceleration, combined angular velocity and human posture angle are selected as the parameters to determine the fall, and the threshold algorithm and SVM algorithm are used to detect the fall. The protective mechanism is an inflatable device based on CO₂ compressed air cylinder, and the equal-width cam structure is applied to its transmission part to improve the puncture efficiency of the compressed gas cylinder. A fall experiment was designed to obtain the combined acceleration and angular velocity eigenvalues of fall actions (forward fall, backward fall and lateral fall) and daily activities (sitting-standing, walking, jogging and walking up and down stairs), showing that the specificity and sensitivity of the protection module reached 92.1% and 84.4% respectively, which verified the feasibility of the fall protection device.
Humans ; Aged ; Monitoring, Ambulatory ; Activities of Daily Living ; Wearable Electronic Devices ; Walking ; Acceleration ; Algorithms

In order to reduce the impact caused by the contact between the foot and the ground when wearing the lower extremity exoskeleton under the condition of high load, this paper proposed an exoskeleton foot mechanism for improving the foot comfort, and optimized the key index of its influence on the comfort. Firstly, the physical model of foot mechanism was established based on the characteristics of foot stress in gait period, and then the mathematical model of vibration was abstracted. The correctness of the model was verified by the finite element analysis software ANSYS. Then, this paper analyzed the influence of vibration parameters on absolute transmissibility based on vibration mathematical model, and optimized vibration parameters with MATLAB genetic algorithm toolbox. Finally, this paper took white noise to simulate the road elevation as the vibration input, and used the visual simulation tool Simulink in MATLAB and the vibration equation to construct the acceleration simulation model, and then calculated the vibration weighted root mean square acceleration value of the foot. The results of this study show that this foot comfort mechanism can meet the comfort indexes of vibration absorption and plantar pressure, and this paper provides a relatively complete method for the design of exoskeleton foot mechanism, which has reference significance for the design of other exoskeleton foot and ankle joint rehabilitation mechanism.
Acceleration ; Ankle Joint ; Biomechanical Phenomena ; Exoskeleton Device ; Finite Element Analysis ; Foot ; Gait ; Humans ; Lower Extremity ; Models, Theoretical ; Vibration

Immune checkpoint blockade targeting PD-1 and PD-L1 has resulted in unprecedented clinical benefit for cancer patients. Anti-PD-1/PD-L1 therapy has become the standard treatment for diverse cancer types as monotherapy or in combination with other anti-cancer therapies, and its indications are expanding. However, many patients do not benefit from anti-PD-1/PD-L1 therapy due to primary and/or acquired resistance, which is a major obstacle to broadening the clinical applicability of anti-PD-1/PD-L1 therapy. In addition, hyperprogressive disease, an acceleration of tumor growth following anti-PD-1/PD-L1 therapy, has been proposed as a new response pattern associated with deleterious prognosis. Anti-PD-1/PD-L1 therapy can also cause a unique pattern of adverse events termed immune-related adverse events, sometimes leading to treatment discontinuation and fatal outcomes. Investigations have been carried out to predict and monitor treatment outcomes using peripheral blood as an alternative to tissue biopsy. This review summarizes recent studies utilizing peripheral blood immune cells to predict various outcomes in cancer patients treated with anti-PD-1/PD-L1 therapy.
Acceleration ; Antigens, CD274 ; Biomarkers ; Biopsy ; Drug-Related Side Effects and Adverse Reactions ; Fatal Outcome ; Humans ; Prognosis ; Programmed Cell Death 1 Receptor

acceleration factors of 2 and 3 (SMS2-DWI and SMS3-DWI, respectively) using a 3T scanner. Acquisition times of the three DWI sequences were measured. Image quality in the three DWI sequences was reviewed by two independent radiologists using a 4-point Likert scale and subsequently compared using the Friedman test. Apparent diffusion coefficient (ADC) values for rectal cancer and the normal rectal wall were compared among the three sequences using repeated measures analysis of variance.RESULTS: Acquisition times using C-DWI, SMS2-DWI, and SMS3-DWI were 173 seconds, 107 seconds, (38.2% shorter than C-DWI), and 77 seconds (55.5% shorter than C-DWI), respectively. For all image quality parameters other than distortion (margin sharpness, artifact, lesion conspicuity, and overall image quality), C-DWI and SMS2-DWI yielded better results than did SMS3-DWI (Ps < 0.001), with no significant differences observed between C-DWI and SMS2-DWI (Ps ≥ 0.054). ADC values of rectal cancer (p = 0.943) and normal rectal wall (p = 0.360) were not significantly different among C-DWI, SMS2-DWI, and SMS3-DWI.CONCLUSION: SMS-DWI using an acceleration factor of 2 is feasible for rectal MRI resulting in substantial reductions in acquisition time while maintaining diagnostic image quality and similar ADC values to those of C-DWI.]]>
Acceleration ; Artifacts ; Diffusion ; Humans ; Magnetic Resonance Imaging ; Rectal Neoplasms ; Rectum

Accompanied by changes in modern work and lifestyle, the incidence of cervical spondylosis has increased year by year. In view of the fact long-term fixed posture of the head and neck is one of the main causes of cervical spondylosis, a set of wearable cervical spondylosis prevention system is developed. The system comprises a head and neck movement collection module based on the acceleration sensor and a head and neck motion recognition module based on artificial intelligence. Experimental results showed that the system can accurately identify long-term posture of the head and neck, and guide users to complete effective exercise therapy under the supervision of motion recognition module. Using this system can be beneficial for the prevention of cervical spondylosis.
Acceleration ; Artificial Intelligence ; Cervical Vertebrae ; Exercise Therapy/instrumentation* ; Humans ; Movement ; Neck ; Posture ; Spondylosis/prevention & control* ; Treatment Outcome ; Wearable Electronic Devices

Role of growth hormone (GH) in mammalian aging is actively explored in clinical, epidemiological, and experimental studies. The age-related decline in GH levels is variously interpreted as a symptom of neuroendocrine aging, as one of causes of altered body composition and other unwelcome symptoms of aging, or as a mechanism of natural protection from cancer and other chronic diseases. Absence of GH signals due to mutations affecting anterior pituitary development, GH secretion, or GH receptors produces an impressive extension of longevity in laboratory mice. Extension of healthspan in these animals and analysis of survival curves suggest that in the absence of GH, aging is slowed down or delayed. The corresponding endocrine syndromes in the human have no consistent impact on longevity, but are associated with remarkable protection from age-related disease. Moreover, survival to extremely old age has been associated with reduced somatotropic (GH and insulin-like growth factor-1) signaling in women and men. In both humans and mice, elevation of GH levels into the supranormal (pathological) range is associated with increased disease risks and reduced life expectancy likely representing acceleration of aging. The widely advertised potential of GH as an anti-aging agent attracted much interest. However, results obtained thus far have been disappointing with few documented benefits and many troublesome side effects. Possible utility of GH in the treatment of sarcopenia and frailty remains to be explored.
Acceleration ; Aging* ; Animals ; Body Composition ; Chronic Disease ; Female ; Growth Hormone* ; Humans ; Life Expectancy ; Longevity ; Male ; Mice ; Sarcopenia

Objective To discuss the application value of vehicle-pedestrian collision road traffic accidents reconstruction based on PC-Crash software in forensic identification. Methods A case of vehicle-pedestrian collision was chosen based on a tachograph, then PC-Crash software was applied to construct a vehicle-pedestrian collision model, and reconstruct the vehicle-pedestrian collision road traffic accident. Finally, the process of vehicle-pedestrian collision was reproduced. Results In accident reconstruction, when the car speed was lower than 50km/h, the landing point of the pedestrian after collision was in the front of the car. When the car speed was higher than 50 km/h, after collision, the pedestrian flipped towards the car roof and landed behind the car. With the increase of vehicle speed, throwing distance of the pedestrian increased continuously. When the vehicle collision speed reached 60 km/h, the experimental results in this case were basically consistent with the actual situation of the case. Head acceleration of the pedestrian was at the maximum （1 655.70 m/s²） at 0.080 s. Chest acceleration of the pedestrian increased from 597.63 m/s² to the peak 675.52 m/s² at 0.055-0.060 s. Tibia acceleration of the pedestrian increased from 759.26 m/s² to the first peak 1 367.06 m/s², then reached the maximum speed （1 718.19 m/s²） at 1.225 s. Conclusion The process of vehicle-pedestrian collision road traffic accidents can be reconstructed based on PC-Crash software under a situation of limited conditions, and can further clarify the speed of the vehicle, the location and degree of human body injury as well as the mechanism of damage of the pedestrian in the accident. Therefore, PC-Crash software has a certain practical value in forensic identification of road traffic accidents.
Acceleration ; Accidents, Traffic ; Forensic Sciences ; Head ; Humans ; Pedestrians ; Software

OBJECTIVE: To compare the image quality of three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) with sparse undersampling and iterative reconstruction (sparse TOF) with that of conventional TOF MRA. MATERIALS AND METHODS: This study included 56 patients who had undergone sparse TOF MRA for intracranial artery evaluation on a 3T MR scanner. Conventional TOF MRA scans were also acquired from 29 patients with matched acquisition times and another 27 patients with matched scanning parameters. The image quality was scored using a five-point scale based on the delineation of arterial vessel segments, artifacts, overall vessel visualization, and overall image quality by two radiologists independently, and the data were analyzed using the non-parametric Wilcoxon signed-rank test. Contrast ratios (CRs) of vessels were compared using the paired t test. Interobserver agreement was calculated using the kappa test. RESULTS: Compared with conventional TOF at the same spatial resolution, sparse TOF with an acceleration factor of 3.5 could reduce acquisition time by 40% and showed comparable image quality. In addition, when compared with conventional TOF with the same acquisition time, sparse TOF with an acceleration factor of 5 could also achieve higher spatial resolution, better delineation of vessel segments, fewer artifacts, higher image quality, and a higher CR (p < 0.05). Good-to-excellent interobserver agreement (κ: 0.65–1.00) was obtained between the two radiologists. CONCLUSION: Compared with conventional TOF, sparse TOF can achieve equivalent image quality in a reduced duration. Furthermore, using the same acquisition time, sparse TOF could improve the delineation of vessels and decrease image artifacts.
Acceleration ; Arteries ; Artifacts ; Humans ; Magnetic Resonance Angiography

OBJECTIVE: To compare conventional sensitivity encoding (SENSE) to compressed sensing plus SENSE (CS) for high-resolution magnetic resonance imaging (HR-MRI) of intracranial and extracranial arteries. MATERIALS AND METHODS: HR-MRI was performed in 14 healthy volunteers. Three-dimensional T1-weighted imaging (T1WI) and proton density-weighted imaging (PD) were acquired using CS or SENSE under the same total acceleration factors (AF(t))-5.5, 6.8, and 9.7 for T1WI and 3.2, 4.0, and 5.8 for PD-to achieve reduced scanning times in comparison with the original imaging sequence (SENSE T1WI, AF(t) 3.5; SENSE PD, AF(t) 2.0) using the 3-tesla system. Two neuroradiologists measured signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), and used visual scoring systems to assess image quality. Acceptable imaging was defined as a visual score ≥ 2. Repeated measures analysis of variance and Cochran's Q test were performed. RESULTS: CS yielded better image quality and vessel delineation than SENSE in T1WI with AF(t) of 5.5, 6.8, and 9.7, and in PD with AF(t) of 5.8 (p < 0.05). CS T1WI with AF(t) of 5.5 and CS PD with AF(t) of 3.2 and 4.0 did not differ significantly from original imaging (p > 0.05). SNR and CNR in CS were higher than they were in SENSE, but lower than they were in the original images (p < 0.05). CS yielded higher proportions of acceptable imaging than SENSE (CS T1WI with AF(t) of 6.8 and PD with AF(t) of 5.8; p < 0.0167). CONCLUSION: CS is superior to SENSE, and may be a reliable acceleration method for vessel HR-MRI using AF(t) of 5.5 for T1WI, and 3.2 and 4.0 for PD.
Acceleration ; Arteries ; Healthy Volunteers ; Magnetic Resonance Imaging ; Methods ; Protons ; Signal-To-Noise Ratio