[Preliminary analysis on X-ray in youth neck type of cervical spondylosis with upper crossed syndrome].

OBJECTIVE: To analyze the X-ray characteristics in youth neck type of cervical spondylosis with upper crossed syndrome(UCS). METHODS: The patients who had a neck type of cervical spondylosis with or without UCS were selected from January to October 2017, 20 cases in each group, and 10 normal volunteers were chosen in the study. X-ray examination of lateral and hyperextension-hyperflexion of cervical spine were performed to observe cervical spine angle, angular displacement and adjacent vertebral body slip. RESULTS: The cervical spine angle was (-0.40±9.64)° in the UCS group, significantly less than (14.35±9.01)° in the normal group and (12.34±5.65)° in the non-UCS group(P<0.05). The change of angular displacement of the upper cervical vertebra in anterior flexion and posterior extension was (8.18±4.81)° in UCS group, which was also significantly less than (12.14±3.48)° in the normal group and (12.34±5.65)° in the non-UCS group(P<0.05). The slippage of the vertebral posterior margin of the lower cervical spine in the anterior flexion was 15.41±2.21 in the UCS group, which was significantly greater than 13.26±2.42 in normal group(P<0.05), and was not obviously different from 15.64±2.07 in non-UCS group(P>0.05). CONCLUSIONS: In young patients who has a neck type of cervical spondylosis with UCS, the cervical curvature prone to straighten or reverse, the upper cervical flexion and extension are limited, while the lower cervical is in a flexion.

Zero difference algorithm for phase shift extraction in blind phase-shifting holography.

A simple noniterative algorithm for retrieval of the unknown phase shifts in phase-shifting holography is proposed. In this algorithm, the phase shift value between two phase-shifting holograms can be calculated through a simple analytical formula that is derived according to the fact that there exist some points whose intensity difference between two phase-shifting holograms is equal to zero. Both the simulated and experimental results demonstrated the feasibility of this so-called zero difference algorithm over a wide range of phase shifts.