Stimulation Generation Method of STEP-NC Process Routing Based on FBM Constrained Relationship

Abstract. The excitation selection sort method of manufacturing feature was proposed based on the characteristics oriented to manufacturing feature of STEP-NC to realize the process route planning of STEP-NC. First, match the recognizing manufacturing feature, the manufacturing feature with multi machining operation was disintegrated in order that every manufacturing feature has only a processing operation. Then, the rationality constraint problems of machining operation was translated into the processing order problem of manufacturing feature, and the optimal constraint problem of machining operation was translated into the corresponding manufacture feature set. The process route was generated by the operations of excitation, selection, deletion and transfer for the feature of different manufacture feature set. The last, the feasibility and effectiveness of the process route excitation generation method was verified by an example, and show that this method was better solved the problems of process rules and the representation of knowledge

Limit Cycles Bifurcated from Some Z

We study the number and distribution of limit cycles of some planar Z4-equivariant quintic near-Hamiltonian systems. By the theories of Hopf and heteroclinic bifurcation, it is proved that the perturbed system can have 24 limit cycles with some new distributions. The configurations of limit cycles obtained in this paper are new

Flexible pressure sensors via engineering microstructures for wearable human-machine interaction and health monitoring applications

Flexible pressure sensors capable of transducing pressure stimuli into electrical signals have drawn extensive attention owing to their potential applications for human-machine interaction and healthcare monitoring. To meet these application demands, engineering microstructures in the pressure sensors are an efficient way to improve key sensing performances, such as sensitivity, linear sensing range, response time, hysteresis, and durability. In this review, we provide an overview of the recent advances in the fabrication and application of high-performance flexible pressure sensors via engineering microstructures. The implementation mechanisms and fabrication strategies of microstructures including micropatterned, porous, fiber-network, and multiple microstructures are systematically presented. The applications of flexible pressure sensors with microstructures in the fields of wearable human-machine interaction, and ex vivo and in vivo healthcare monitoring are comprehensively discussed. Finally, the outlook and challenges in the future improvement of flexible pressure sensors toward practical applications are presented

A cross-cultural study of domestic luminous environment in the United Kingdom and Japan

Abstract not available

MARVEL: A Randomized Double‐Blind, Placebo‐Controlled Trial in Patients Undergoing Endovascular Therapy: Study Rationale and Design

BACKGROUND Steroids have pleiotropic neuroprotective actions including the regulation of inflammation and apoptosis which may influence the effects of ischemia on neurons, glial cells, and blood vessels. The effect of low‐dose methylprednisolone in patients with acute ischemic stroke in the endovascular therapy era remains unknown. This trial investigates the efficacy and safety of low‐dose methylprednisolone (2 mg/kg IV for 3 days) as adjunctive therapy for patients with acute ischemic stroke undergoing endovascular therapy within 24 hours from symptom onset. METHODS The MARVEL(Methylprednisolone as Adjunctive Therapy for Acute Large Vessel Occlusion: A Randomized Double‐Blind, Placebo‐Controlled Trial in Patients Undergoing Endovascular Therapy) trial is an investigator‐initiated, prospective, randomized, double‐blind, placebo‐controlled multicenter clinical trial. Up to 1672 eligible patients with anterior circulation large‐vessel occlusion stroke presenting within 24 hours from symptom onset are planned to be consecutively randomized to receive methylprednisolone or placebo in a 1:1 ratio across 82 stroke centers in China. RESULTS The primary outcome is the ordinal shift in the modified Rankin scale score at 90 days. Secondary outcomes include 90‐day functional independence (modified Rankin scale score, 0–2). The primary safety end points include mortality rate at 90 days and symptomatic intracerebral hemorrhage within 48 hours of endovascular therapy. CONCLUSION The MARVEL trial will provide evidence of the efficacy and safety of low‐dose methylprednisolone as adjunctive therapy for patients with anterior circulation large‐vessel occlusion stroke undergoing endovascular therapy

Tirofiban for Stroke without Large or Medium-Sized Vessel Occlusion

The effects of the glycoprotein IIb/IIIa receptor inhibitor tirofiban in patients with acute ischemic stroke but who have no evidence of complete occlusion of large or medium-sized vessels have not been extensively studied. In a multicenter trial in China, we enrolled patients with ischemic stroke without occlusion of large or medium-sized vessels and with a National Institutes of Health Stroke Scale score of 5 or more and at least one moderately to severely weak limb. Eligible patients had any of four clinical presentations: ineligible for thrombolysis or thrombectomy and within 24 hours after the patient was last known to be well; progression of stroke symptoms 24 to 96 hours after onset; early neurologic deterioration after thrombolysis; or thrombolysis with no improvement at 4 to 24 hours. Patients were assigned to receive intravenous tirofiban (plus oral placebo) or oral aspirin (100 mg per day, plus intravenous placebo) for 2 days; all patients then received oral aspirin until day 90. The primary efficacy end point was an excellent outcome, defined as a score of 0 or 1 on the modified Rankin scale (range, 0 [no symptoms] to 6 [death]) at 90 days. Secondary end points included functional independence at 90 days and a quality-of-life score. The primary safety end points were death and symptomatic intracranial hemorrhage. A total of 606 patients were assigned to the tirofiban group and 571 to the aspirin group. Most patients had small infarctions that were presumed to be atherosclerotic. The percentage of patients with a score of 0 or 1 on the modified Rankin scale at 90 days was 29.1% with tirofiban and 22.2% with aspirin (adjusted risk ratio, 1.26; 95% confidence interval, 1.04 to 1.53, P = 0.02). Results for secondary end points were generally not consistent with the results of the primary analysis. Mortality was similar in the two groups. The incidence of symptomatic intracranial hemorrhage was 1.0% in the tirofiban group and 0% in the aspirin group. In this trial involving heterogeneous groups of patients with stroke of recent onset or progression of stroke symptoms and nonoccluded large and medium-sized cerebral vessels, intravenous tirofiban was associated with a greater likelihood of an excellent outcome than low-dose aspirin. Incidences of intracranial hemorrhages were low but slightly higher with tirofiban

Gravity-Based Kinetostatic Modeling of Parallel Manipulators Using Screw Theory

Abstract The pose accuracy of parallel manipulators (PMs) is a key index to measure their performance. Establishing the gravity-based kinetostatic model of a parallel robot provides an important basis for its error composition and accuracy improvement. In this paper, a kinetostatic modeling approach that takes real gravity distribution into consideration is proposed to analyze the influence of gravity on the infinitesimal twist and actuator forces of PMs. First, the duality of the twist screw and constraint wrenches are used to derive the gravity-attached constraint wrenches independent of the external load and the limb stiffness matrix corresponding to the kinematics-based constraint wrenches. Second, the gravity model of the mechanism is established based on the screw theory and the principle of virtual work. Finally, the analytical formulas of the infinitesimal twist and the actuator force of PMs are obtained, and the influences of the external load, platform gravity, and rod gravity on the stiffness of the mechanism are decoupled. The non-overconstrained 3RPS and overconstrained 2PRU-UPR PMs are taken as examples to verify the proposed method. This research proposes a methodology to analyze the infinitesimal deformation of the mechanism under the influence of gravity