[The effects of postauricular injection of methylprednisolone on medium-high frequency sudden hearing loss].

Objective:To study the effects of postauricular injection of methylprednisolone on medium-high frequency sudden hearing loss.Method:The data of 45 patients with invalid treatment who were diagnosed as medium-high frequency sudden hearing loss were retrospectively studied. They were divided into postauricular injection group and non-postauricular injection group. The treatment efficiency and hearing improvement at each frequency were compared between the two groups.Result:The improvements of hearing threshold in the non-postauricular injection group were(6.30±5.00)dB HL,(3.80±5.52)dB HL,(5.35±5.50)dB HL,(15.60±11.84)dB HL,(19.60±13.46)dB HL,(15.40±12.90)dB HL at 250, 500, 1000, 2000, 4000 and 8000Hz, respectively. The hearing improvements of the postauricular injection group were (5.35±6.22)dB HL,(2.50±3.00)dB HL,(4.65±6.60)dB HL,(23.75±10.75)dB HL,(25.75±11.73)dB HL,(30.50±14.50)dB HL at 250, 500,1000,2000,4000 and 8000Hz, respectively. There were significant differences between the two groups in hearing improvements at 2000-8000Hz. The treatment effective rates were 44% and 80% for the non-postauricular injection group and postauricular injection group respectively, which showed a significant difference(χ²=8.385P<0.05).Conclusion:Postauricular injection of methylprednisolone as a remedy treatment is safe and effective for sudden hearing loss in middle and high frequency.

High corrosion resistance and weak corrosion anisotropy of an as-rolled Mg-3Al-1Zn (in wt.%) alloy with strong crystallographic texture.

Combining with electrochemical corrosion measurements, immersion and hydrogen evolution testing performed in 0.9 wt.% NaCl solution at 37 °C, the corrosion resistance of an as-rolled Mg-3%Al-1%Zn alloy before and after a 3% compressive strain along the rolling direction was investigated. Results revealed that the corrosion behavior of differently oriented surfaces of the as-rolled samples with a strong basal texture was obviously different. Among them, the corrosion rate of sample surface with the orientation parallel to the normal direction (ND) of the plate was the fastest, the corrosion rate of sample surface with the orientation parallel to the rolling direction (RD) of the plate took the second place and the corrosion rate of sample surface with the orientation parallel to the transverse direction (TD) was the slowest. After being pre-strained, the activation of a high density of {10-12} twins could remarkably reduce the corrosion rate of surrounding α-Mg matrix and simultaneously weaken the corrosion anisotropy between differently oriented samples. The main reason was that similar to grain boundaries, twin boundaries acted as physical barriers to the corrosion attack. Moreover, the activated twins increased the protectiveness of surface films and then suppressed the micro corrosion couples occurred in twinned grains.

Surface hardening of NiTi shape memory alloy induced by the nanostructured layer after surface mechanical attrition treatment.

To conduct grain refinement induced by plastic deformation, NiTi shape memory alloy is processed by surface mechanical attrition treatment. The process leads to surface nanocrystallization and consequently surface hardening. The cross sectional microhardness of the treated NiTi is measured and compared to those of annealed NiTi specimens with residual stress relaxation and recrystallization. Our results show that surface nanocrystallization induced by surface mechanical attrition treatment is an effective method to enhance the surface hardness and anti-wear properties of NiTi shape memory alloy for the biomedical application.

Cavity design and characteristics of monolithic long-wavelength InAs/InP quantum dash passively mode-locked lasers.

By extending the net-gain modulation phasor approach to account for the discrete distribution of the gain and saturable absorber sections in the cavity, a convenient model is derived and experimentally verified for the cavity design of two-section passively mode-locked quantum dash (QDash) lasers. The new set of equations can be used to predict functional device layouts using the measured modal gain and loss characteristics as input. It is shown to be a valuable tool for realizing the cavity design of monolithic long-wavelength InAs/InP QDash passively mode-locked lasers.

Reconfigurable quantum dot monolithic multisection passive mode-locked lasers.

We investigate the dynamical response of a quantum dot photonic integrated circuit formed with a combination of eleven passive and active gain cells operating when these cells are appropriately biased as a multi-section quantum dot passively mode-locked laser. When the absorber section is judiciously positioned in the laser cavity then fundamental frequency and harmonic mode-locking at repetition rates from 7.2GHz to 51GHz are recorded. These carefully engineered multi-section configurations that include a passive wave-guide section significantly lower the pulse width up to 34% from 9.7 to 6.4 picoseconds, as well increase by 49% the peak pulsed power from 150 to 224 mW, in comparison to conventional two-section configurations that are formed on the identical device under the same average power. In addition an ultra broad operation range with pulse width below ten picoseconds is obtained with the 3rd-harmonic mode-locking configuration. A record peak power of 234 mW for quantum dot mode-locked lasers operating over 40 GHz is reported for the first time.