The obliquus capitis inferior myodural bridge

This study was designed to examine the obliquus capitis inferior (OCI) muscle from a gross anatomical perspective. The objective was to isolate and identify the OCI myodural bridge, while examining its course and contributing elements. An earlier study of the posterior cervical spine briefly reported a connection between the OCI and the cervical dura mater. To the best of our knowledge, a study has not yet been conducted specifically on this muscle and its relation to the dura mater. In this study, the suboccipital regions of nine embalmed cadavers were dissected. A total of 14 OCI muscles were isolated for examination. All findings were documented via photograph. Of the 14 OCI muscles isolated, all emitted fibrous tissue bands from the anterolateral portion of the muscular belly. These fibers attached to the posterolateral cervical dura mater by route of the atlantoaxial interspace. The OCI myodural bridge appeared to coalesce with the rectus capitis posterior major myodural bridge, giving the appearance of a single atlantoaxial structure that links these two muscles to the dura mater. In conclusion, the OCI was attached to the dura mater in all of the 14 muscle specimens. We hypothesize that the OCI myodural bridge may play a physiological role in monitoring dural tension and preventing dural infolding. It may also contribute to certain clinical symptoms manifesting from alterations in dural tone. Clin. Anat. 2013. © 2012 Wiley Periodicals, Inc.     

固定桥不同桥体龈端形态修复下颌第一磨牙的三维有限元分析

目的　应用三维有限元分析法探讨不同桥体龈端形态对固定桥基牙及牙周膜应力分布的影响。方法　利用健康成人牙列的锥形束CT（CBCT）原始数据，通过三维建模软件建立下颌第一磨牙缺失，第二前磨牙与第二磨牙为基牙的双端固定桥，并模拟三种不同桥体龈端形态，即改良鞍式、改良盖嵴式、船底式。利用Ansys 17.0对已建立的三种不同龈端形态的固定桥有限元模型加载垂直向载荷，分析固定桥基牙牙本质、牙周膜的应力分布情况。结果　①三种龈端形态的固定桥在相同载荷条件下第二前磨牙牙周膜应力均较第二磨牙应力值大；②桥体龈端形态均不会影响单个基牙应力分布的规律；但与其他两种形态的修复体相比，船底式龈端形态的单根基牙综合应力值更小，且双根牙综合应力值更大；③固定桥受垂直载荷时三组桥体基牙牙周膜综合应力分布大小依次为：改良鞍式＜改良盖嵴式＜船底式，但三者应力均未超出基牙牙周储备力，只是随着桥体龈端面积减小，基牙动用的牙周储备力增加。结论　①磨牙是比较理想的基牙，在修复时，应首先考虑的是前磨牙的牙周支持力是否充足；②船底式固定桥修复后更有利于保护单根基牙，改善固定桥应力分布；③三种龈端修复形态下基牙牙周支持组织都能承担日常咬合力，对基牙牙周膜健康无影响。     

Microelectronic neural bridging of toad nerves to restore leg function

The present study used a microelectronic neural bridge comprised of electrode arrays for neural signal detection, functional electrical stimulation, and a microelectronic circuit including signal amplifying, processing, and functional electrical stimulation to bridge two separate nerves, and to restore the lost function of one nerve. The left leg of one spinal toad was subjected to external mechanical stimulation and functional electrical stimulation driving. The function of the left leg of one spinal toad was regenerated to the corresponding leg of another spinal toad using a microelectronic neural bridge. Oscilloscope tracings showed that the electromyographic signals from controlled spinal toads were generated by neural signals that controlled the spinal toad, and there was a delay between signals. This study demonstrates that microelectronic neural bridging can be used to restore neural function between different injured nerves.     

Complete Sella Turcica Bridges Prevalence and Dimensions

Interclinoid ligaments which connect the anterior and posterior clinoid processes comprise a group of intrinsic ligaments of sphenoid bone. The complete sella turcica bridge corresponds to the complete ossification of the interclinoid ligaments. 112 dry human adult skull bones were studied for presence of ossified interclinoid ligaments. Nine skulls (8.04%) showed sella turcica bridges, out of which six were unilateral and three bilateral. The average length of the bridge was 11.67mm. The average width and thickness at the anterior clinoid process was 6.33mm and 4.33mm ; atthe middle of the bridge 3.08mm and 2.66mm; and atthe posterior clinoid process, 4.91 mm and 3.66mm, respectively. Anomalies of sellar region are not very rare and may pose difficulties in interpretation of Magnetic Resonance Imaging or Computed Tomographyforthe radiologist. Thesefindings would also guide the neurosurgeons in planning neurosurgical procedures involving the sellar region.     

Effect of Aloe vera. on Rat Pulp Tissue

Abstract

Aloe vera. L. (Aloeaceae) has been extensively studied for anti-inflammatory, antimicrobial, and cellular regeneration properties. This work evaluated in vivo. the effects of powder of freeze-dried Aloe vera. on rat pulp tissue. Pulp tissue was mechanically exposed to Aloe vera., and it was evaluated at 1 to 30 days after the procedure by histopathologic examination. A predominant acute-moderate inflammatory infiltrate was observed in the Aloe vera.–treated group 1 to 7 days after treatment. At 14 to 30 days, pulp tissue took a normal pattern when comparing Aloe vera. treatment with the Ca(OH)₂ treatment; it was found that both treatment groups stimulated reparative dentin and the formation of complete bridge. Strong superficial necrosis was detected exclusively for Ca(OH)₂. It seems evident that application of Aloe vera. in direct contact with the exposed pulp has acceptable biocompatibility and can lead to tertiary bridge formation.     

基于三相桥臂坐标的SVPWM过调制方法

讨论了一种新型的SVPWM过调制方法，并对其过调制性能及谐波成分进行了分析。首先，对经典SVPWM技术进行了分析，探讨了常规过调制策略的实质。其次，引入了新的三相桥臂坐标，在该坐标下将现有的SVPWM的串行合成时间关系推导为并行。最后，给出了线性调制和过调制统一的求解模型，避免了现有过调制算法中控制角和保持角的计算。新方法取消了扇区的概念并简化了计算，可实现从线性调制到六阶梯模式的连续平滑调制。文中介绍了该过调制算法的基本原理，进行了仿真和实验。结果表明，该方法在线性调制和六阶梯模式下调制效果与经典SVPWM方法相当；而过调制区，其输出PWM波形的THD明显小于常规过调制方法。     

Neuroarchitecture of the central complex of the desert locust: Tangential neurons

The central complex (CX) comprises a group of midline neuropils in the insect brain, consisting of the protocerebral bridge (PB), the upper (CBU) and lower division (CBL) of the central body and a pair of globular noduli. It receives prominent input from the visual system and plays a major role in spatial orientation of the animals. Vertical slices and horizontal layers of the CX are formed by columnar, tangential, and pontine neurons. While pontine and columnar neurons have been analyzed in detail, especially in the fruit fly and desert locust, understanding of the organization of tangential cells is still rudimentary. As a basis for future functional studies, we have studied the morphologies of tangential neurons of the CX of the desert locust Schistocerca gregaria. Intracellular dye injections revealed 43 different types of tangential neuron, 8 of the PB, 5 of the CBL, 24 of the CBU, 2 of the noduli, and 4 innervating multiple substructures. Cell bodies of these neurons were located in 11 different clusters in the cell body rind. Judging from the presence of fine versus beaded terminals, the vast majority of these neurons provide input into the CX, especially from the lateral complex (LX), the superior protocerebrum, the posterior slope, and other surrounding brain areas, but not directly from the mushroom bodies. Connections are largely subunit- and partly layer-specific. No direct connections were found between the CBU and the CBL. Instead, both subdivisions are connected in parallel with the PB and distinct layers of the noduli.     

冠状动脉心肌桥的诊疗现状与研究进展

由于冠状动脉心肌桥患者通常无症状,长期以来,这一解剖异常一直被认为是一种良性变异。但是,随着冠状动脉造影技术的应用普及和临床研究的深入,越来越多学者认为心肌桥可能发生严重并发症,甚至威胁人类生命。目前其发病机制、诊断及治疗已经得到广泛的关注和研究,但尚无明确的指南指导临床诊疗。文章就心肌桥的发病率、病理生理、诊疗现状及研究进展进行综述,为心肌桥的规范化诊治提供依据,使越来越多患者受益。