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).

Cytochrome P450 1A1 (CYP1A1) Catalyzes Lipid Peroxidation of Oleic Acid-Induced HepG2 Cells.

Nonalcoholic fatty liver disease (NAFLD) is a chronic hepatic disease associated with excessive accumulation of lipids in hepatocytes. As the disease progresses, oxidative stress plays a pivotal role in the development of hepatic lipid peroxidation. Cytochrome P450 1A1 (CYP1A1), a subtype of the cytochrome P450 family, has been shown to be a vital modulator in production of reactive oxygen species. However, the exact role of CYP1A1 in NAFLD is still unclear. The aim of this study was to investigate the effects of CYP1A1 on lipid peroxidation in oleic acid (OA)-treated human hepatoma cells (HepG2). We found that the expression of CYP1A1 is elevated in OA-stimulated HepG2 cells. The results of siRNA transfection analysis indicated that CYP1A1-siRNA inhibited the lipid peroxidation in OA-treated HepG2 cells. Additionally, compared with siRNA-transfected and benzo[a]pyrene (BaP)-OA-induced HepG2 cells, overexpression of CYP1A1 by BaP further accelerated the lipid peroxidation in OA-treated HepG2 cells. These observations reveal a regulatory role of CYP1A1 in liver lipid peroxidation and imply CYP1A1 as a potential therapeutic target.

[Treatment of sudden deafness with type 2 diabetesmellitus by post-auricular subperiosteal injection of methylprednisolone].

Objective:To investigate the therapeutic effect of post-auricular subperiosteal injection of methylprednisolone combined with ginkgo biloba injection and mouse nerve growth factor in sudden deafness with type 2 diabetesmellitus. To understand the effect of post-auricular subperiosteal injection of methylprednisolone on type 2 diabetesmellitus complicated with sudden deafness and its effect on blood-glucose level, and to explore a more effective and safe method for treating this special group of sudden deafness. Method: Total 84 patients suffered from type 2 diabetesmellitus with sudden deafness and treated in Shaanxi Provincial People's Hospital from March 2017 to June 2018 were randomly divided into experimental group(post-auricular subperiosteal injection of methylprednisolone+ginkgo biloba injection, mouse nerve growth factor)(n=48) and a control group(ginkgo biloba injection, mouse nerve growth factor)(n=36). Each group was divided into high frequency, low frequency and flat and total deafness group. Then to compare the clinical efficacy of the two groups and the difference of the fluctuation of blood glucose and HbA1c before treatment and 2 hours after treatment. Result:①The effective rate of treatment in the experimental group was 79.17%, higher than that in the control group(58.33%), P<0.05. The results indicated that the effect of post-auricular subperiosteal injection of methylprednisolone combined with ginkgo biloba injection and mouse nerve growth factor was effective in sudden deafness with type 2 diabetesmellitus. ②There was no significant difference in the fluctuation of blood glucose and HbA1c before treatment and 2 hours after treatment in the experimental group, and it indicated that this treatment can effectively avoid systemic side effects of steroid and ensure the safety of the treatment. Conclusion:Post-auricular subperiosteal injection of methylprednisolone combined with ginkgo biloba injection and mouse nerve growth factor is effective in patients with sudden deafness with type 2 diabetesmellitus, furthermore, blood glucose will not be affected by the using of steroid, and it will aviod systemic hormonal side effects.