In order to characterize the characteristics of pathological tremor of human upper limb, a simulation system of pathological tremor of human arm was provided and its dynamic response was analyzed. Firstly, in this study, a two-degree-of-freedom human arm dynamic model was established and linearized according to the arbitrary initial angle of joints. After solving the analytical solutions of steady-state responses of the joints, the numerical solution was used to verify it. The results of theoretical analysis show that the two natural frequencies of the developed dynamic model are 2.9 Hz and 5.4 Hz, respectively, which meet the characteristic frequency range of pathological tremors. Then, combined with the measured parameters of human arm, a tremor simulation system was built, and the measured results of joint responses are in good agreement with the theoretical and simulation analysis results, which verifies the effectiveness of the theoretical model. The results show that the human arm pathological tremor simulation system designed in this paper can characterize the frequency and response amplitude of the human upper limb pathological tremor. Moreover, the relevant research lays a theoretical foundation and experimental conditions for the subsequent development of wearable tremor suppression devices.
The large force applied by laparoscopic grasper during clamping operation can cause tissue damage and induce various complications. In this research, the security of graspers with different radii of curvature and teeth were evaluated by using experimental investigation, finite element simulation and tissue damage assessment method based on in vivo compression tests with rabbit large intestines models. Results showed that the most serious tissue damages appeared in areas that were in contact with the jaw edges, which were the regions of stress concentration. The increase in radii of curvature of the edges or teeth could alleviate the tissue damages. The results could provide basic data for choosing and designing noninvasive graspers.
Axon guidance molecules, slit glycoprotein (Slit) and Roundabout receptors (Robo) were firstly identified in the central neural system of Drosophila melanogaster. The Slit-Robo signal plays a crucial role in axon guidance, inflammation, tumor metastasis and angiogenesis, of which the role of Slit2-Robo pathway in angiogenesis has drawn a greater attention and still remains conflicting. Herein, we provide a review on the role of Slit2-Robo pathway in ocular angiogenesis and vascularization of other organs and systems. We hope this review will be the basis of further study on the mechanism of Slit2-Robo signaling on angiogenesis and provide new target for the therapy on ocular vascular disease
ObjectiveTo observe the macular choroidal and retinal pigment epithelium (RPE) thickness in tilted disc syndrome (TDS). MethodsThis is a descriptive study. Thirty eyes of 22 TDS patients (TDS group) and 30 eyes of 15 normal subjects (control group) were analyzed. Among TDS group, there were 8 males (11 eyes) and 14 females (19 eyes), the average age was (9.00±2.78) years old. The best corrected visual acuity (BCVA) was 0.3-1.0, and the average spherical equivalent degree was (-3.44±2.22) DS. Among the control group, there were 8 males (16 eyes) and 7 females (14 eyes), the average age was (9.33±1.11) years old. The best corrected visual acuity (BCVA)≥1.0, and the average spherical equivalent degree was (-3.18±1.13)DS. The difference of the spherical equivalent degree between two groups was not statistically significant (t=-1.648, P=0.110). Enhanced depth imaging techniques of frequency-domain optical coherence tomography was used to measure the thickness of choroid and RPE at totally 17 sites. There sites included subfoveal, 4 sites each (500, 1000, 1500 and 2000 μm from the fovea) at the horizontal (nasal/temple) and vertical (superior/inferior) directions. ResultsThe subfoveal choroidal thickness was (235.53±51.77) μm and (273.45±60.3) μm in TDS patients and control respectively, the difference was significant(t=-2.612,P=0.011). The difference of the choroidal thickness of the other 8 horizontal sites (F=24.180) and 8 vertical sites (F=23.390) in TDS group was statistically significant (P=0.000). The TDS choroidal thickness of all horizontal sites except nasal 1000 μm site was thinner than corresponding sites of the control group (P<0.05). The TDS choroidal thickness of the subfoveal site and 4 inferior vertical sites was thinner than corresponding sites of the control group (P<0.05). The subfoveal RPE thickness was (32.56±5.00) μm and (36.58±3.60) μm in TDS patients and control respectively, the difference was significant(t=-3.567,P=0.001). The subfoveal RPE thickness was the thickest among other 16 sites in both groups, and the TDS RPE thickness of all sites was thinner than control group, the difference was statistically significant (P<0.05). ConclusionThe choroidal and RPE thickness of TDS patient was thinner than normal subjects.
Diffuse choroidal retinal atrophy (DCA) is a type of myopic macular disease that presents with yellowish-white atrophic changes at the posterior pole of the eyeball. DCA is an important critical feature in the diagnosis of pathological myopia. Early intervention and treatment of this disease are of great significance in delaying the progression of pathological myopia and reducing the impairment of visual function. Ophthalmic imaging data can be used to diagnose the disease, and color fundus photography is the most simple and intuitive. Choroidal thickness is also a key indicator in the diagnosis of DCA, but the diagnostic critical value of choroidal thickness has not been clearly defined. With the development and popularization of artificial intelligence technology, the analysis of lesion imaging data is more objective and accurate. In the future, it is expected to actively establish a standard quantitative evaluation system for DCA by means of artificial intelligence to achieve early detection, early diagnosis and early treatment of pathological myopia.
Pathological myopic tractional maculopathy (MTM), as an important type of macular lesions associated with high myopia, play a significant role in the prevention and treatment of myopic macular diseases. With the rapid development of retinal imaging technologies, especially the widespread application of optical coherence tomography, new technical support has been provided for the accurate diagnosis, clinical staging, treatment decision-making, and long-term follow-up of MTM. However, in clinical practice in China, there are still issues such as unclear definitions, inconsistent staging criteria, and significant differences in treatment strategies. To address these challenges, Fundus Diseases Group in Ophthalmology Branch of Chinese Medical Association and Professional Committee of Fundus Diseases in Ophthalmology Branch of Chinese Medical Doctor Association for Ophthalmologists jointly drafted the Expert consensus on management of pathologic myopic tractional maculopathy in China, based on a systematic literature review and the latest clinical evidence. The consensus was revised multiple times by the core expert group and finally finalized. This consensus systematically establishes a standardized diagnostic and therapeutic system for MTM, covering disease definition and staging, diagnostic pathways and follow-up protocols, treatment strategies based on staging, and surgical intervention plans. It aims to provide ophthalmologists at all levels with a scientifically sound and practically applicable clinical guidance. The development of the consensus strictly adheres to the principles of evidence-based medicine, fully considering the actual clinical conditions of medical institutions at different levels in China. It provides principled recommendations with broad guiding significance for the clinical practice of MTM. It is particularly emphasized that when applying this consensus, clinicians should comprehensively consider the patient’s clinical characteristics, treatment accessibility, and socioeconomic factors, and implement personalized and precise treatment strategies to meet the diverse clinical needs of patients with pathological myopia.