Algorithms based on deep neural networks (DNNs) have attracted increasing attention from the scientific computing community. DNN based algorithms are
easy to implement, natural for nonlinear problems, and have shown great potential to
overcome the curse of dimensionality. In this work, we utilize the multi-scale DNN-based algorithm (MscaleDNN) proposed by Liu, Cai and Xu (2020) to solve multi-scale
elliptic problems with possible nonlinearity, for example, the p-Laplacian problem.
We improve the MscaleDNN algorithm by a smooth and localized activation function.
Several numerical examples of multi-scale elliptic problems with separable or non-separable scales in low-dimensional and high-dimensional Euclidean spaces are used
to demonstrate the effectiveness and accuracy of the MscaleDNN numerical scheme. 相似文献
BackgroundNovel patterns of electrical stimulation of the brain and spinal cord hold tremendous promise to improve neuromodulation therapies for diverse disorders, including tremor and pain. To date, there are limited numbers of experimental studies in human subjects to help explain how stimulation patterns impact the clinical response, especially with deep brain stimulation.We propose using novel stimulation patterns during electrical stimulation of somatosensory thalamus in awake deep brain stimulation surgeries and hypothesize that stimulation patterns will influence the sensory percept without moving the electrode.MethodsIn this study of 15 fully awake patients, the threshold of perception as well as perceptual characteristics were compared for tonic (trains of regularly-repeated pulses) and bursting stimulation patterns.ResultsIn a majority of subjects, tonic and burst percepts were located in separate, non-overlapping body regions (i.e., face vs. hand) without moving the stimulating electrode (p < 0.001; binomial test). The qualitative features of burst percepts also differed from those of tonic-evoked percepts as burst patterns were less likely to evoke percepts described as tingling (p = 0.013; Fisher’s exact test).ConclusionsBecause somatosensory thalamus is somatotopically organized, percept location can be related to anatomic thalamocortical pathways. Thus, stimulation pattern may provide a mechanism to select for different thalamocortical pathways. This added control could lead to improvements in neuromodulation - such as improved efficacy and side effect attenuation - and may also improve localization for sensory prostheses. 相似文献
ObjectiveDeep brain stimulation (DBS) surgery has its own set of risks and complications. This study from a single center and a single surgeon analyzes various risk factors for complications and tries to establish if there is a learning curve effect in minimizing the complications.Materials and MethodsA retrospective analysis of 519 patients (1024 leads) who underwent DBS surgery and 232 patients who underwent implantable pulse generator replacement (IPG), by a single surgeon, between the years 1999 and 2019 was performed. Perioperative and hardware related complications were evaluated.ResultsThe follow-up period ranged from six months to 20 years. Surgery-related complications occurred in 46 (8.9%) cases which included confusion in 31 (5.98%), intracerebral hemorrhage in 7 (1.3%), vasovagal attack in 3 (0.58%), respiratory distress in 2 (0.38%), postoperative aggressiveness in 1 (0.19%), and blepharospasm in 2 (0.38%) patients. Complications related to the DBS hardware were found in 35 cases, including erosion and infection in 22 (2.95%), inaccurate lead placement or migration in 6 (0.6%) lead fracture/extension wire failure in 2 (0.26%), IPG malfunction in 2 (0.26%), and hardware discomfort in 3 (0.4%) cases. In three patients, one lead was repositioned. In cases of infection, 87% of patients had either partial or complete removal of hardware. There was no mortality. The complications were analyzed for every 100 DBS procedures. There was a significant drop in the percentage of complications in from 23% in the first 100 cases to 7% in the last 100 cases (p < 0.0001).ConclusionConfusion remains the most frequent operative and perioperative complication. Erosion and infection of the surgical site represents the most frequent hardware complication. DBS surgery is safe and the complication rates are acceptably low. The complication rate also decreases with cumulative years of experience, demonstrating a learning curve effect. 相似文献
Infections of the ear, nose and throat are common. The majority of these infections are managed by the primary care physicians and they settle with conservative and medical management. However, a small group can progress to become troublesome and develop complications to the extent that they may require surgical intervention. Some of the infections can lead to life-threatening complications, therefore awareness and correct diagnosis along with appropriate management is paramount. Foreign bodies in the ear, nose and throat are commonly encountered. The location and type of foreign body can have an implication on the urgency of action and the possible complications. In this article the common ENT infections and foreign bodies and their management are discussed. 相似文献
Objective: To perform a systematic review and meta-analysis comparing effectiveness and safety of moderate and deep sedation during colonoscopy.
Research design and methods: We searched Medline, Embase, Central and Google scholar in May 2017 and updated in March 2018 to identify all randomized controlled trials that compared the effectiveness and safety of moderate and deep sedation during colonoscopy. The quality of studies was assessed using the “Risk of bias” tool. The primary endpoints were defined as patient satisfaction, physician satisfaction, incidence of recall and incidence of desaturation. Recovery time was also evaluated. Review Manager and Comprehensive Meta-Analysis software were used for statistical analysis.
Results: A total of 919 patients from three studies were included in the final analysis. The combined analysis did not reveal any differences in patient satisfaction between moderate and deep sedation (RR?=?0.94; 95% CI: 0.86 to 1.04; Pchi2?=?0.06; I2?=?65%; number needed to treat to harm [NNTH]?=?15.6; 95% CI: NNTH 7.8 to ∞ to number needed to treat to benefit [NNTB]?=?3078.0), physician satisfaction (RR?=?0.35; 95% CI: 0.02 to 6.95; Pchi2 < 0.001; I2?=?100%; NNTB?=?1.6; 95% CI: 1.5 to 1.8), incidence of recall (RR?=?5.82; 95% CI: 0.51 to 66.48; Pchi2?=?0.11; I2?=?60%; NNTH?=?11.0; 95% CI: 7.5 to 20.5) or recovery time (mean difference?=?-6.77; 95% CI: -16.21 to 2.67; Pchi2 < 0.001; I2?=?99%). However, incidence of desaturation was higher in the deep group than in the moderate group (RR?=?0.18; 95% CI: 0.01 to 0.99; Pchi2?=?0.48; I2?=?0%; NNTB?=?56.7; 95% CI: 31.6 to 273.1).
Conclusions: Moderate sedation showed comparable safety and effectiveness to deep sedation with respect to patient satisfaction, physician satisfaction, incidence of recall and recovery time. 相似文献