Design, modeling, and testing of a one degree of freedom manipulator with three-stage amplification mechanism

The one degree of freedom (1-DOF) manipulator with nano-resolution is a significant component in the micro-/nano-manipulation. In order to simultaneously achieve a large stroke and high precision, a piezo-driven 1-DOF flexure-based manipulator consisting of an enhanced double Scott-Russell mechanism (EDSRM), a lever type mechanism, and a Z-shaped mechanism is proposed in this paper. Analytical models are developed to examine the kinetostatic and dynamic properties of the manipulator. A finite element analysis is further performed to evaluate the characteristics of the EDSRM and the complete manipulator. The prototype is fabricated on monolithic AL7075, and various experimental tests have been carried out to investigate the correctness of the modeling. The experimental results show that the proposed manipulator has a satisfactory amplification ratio, static stability, and dynamic performance.

[Clinical application of seven-item Eustachian Tube Dysfunction Questionnaire]

Objective: To investigate the clinical value of the seven-item Eustachian Tube Dysfunction Questionnaire(ETDQ-7) in evaluating Eustachian tube dysfunction before and after treatment.Method: A retrospective analysis of 50 patients with Eustachian tube dysfunction diagnosed. All the patients were given chymotrypsin 4 000 IU and dexamethasone injection 5 mg by blowing through the Eustachian tube under nasal endoscopic guidance once daily for 3-6 consecutive days. At the same time, azelastine hydrochloride nasal spray and budesonide nasal spray were applied, 2 sprays each time, 2 times a day; oral Olongma drops, 3 ml each time, 3 times a day. ETDQ-7 was completed before and after treatment, and the results of ear endoscopy, pure tone audiometry, acoustic impedance test, and Eustachian tube function test were analyzed comprehensively. Result: The ETDQ-7 score(15.6±7.1) after treatment was significantly higher than that before treatment(23.1±6.5) points (P<0.05), and the difference was statistically significant. After treatment, all patients felt that aural fullness, tinnitus or discomfort, hearing loss and other symptoms were relieved. The tympanic membrane was observed to be better than before treatment. The tympanic effusion and tympanic membrane invagination were improved, which was in line with the change of ETDQ-7 score. Conclusion: ETDQ-7 has a good clinical value in the evaluation of Eustachian tube dysfunction before and after treatment. It is a reproducible and effective method for evaluating Eustachian tube dysfunction(ETD).