Develeperment medicine child neurology 2002 Dec :44(12) 849-851 Neil Gordon 病例摘要 1 • 男性,婴儿期发病。 • 神经系统全面性损害,以智能及运动发育 迟滞伴倒退为主。 • 肌阵挛发作,脑电图可见癫痫样放电。 • 双视神经损害、眼底视神经萎缩。 • 头颅核磁示全脑萎缩,小脑为主。 视神经萎缩,视力丧失 • 听力减退 • 癫痫及锥体外系症状 • 痴呆及死亡(10岁以前) 其他少见症状及体征 • 足趾行走(Toe-walking) • 严重便秘 • 急性恶化的共济失调及肌张力减低 • (常在小外伤及发热后) • 伴有小头畸形,骨硬化症,胼胝体发育不 全 诊断 • 确诊: • 组织活检:脑,神经,肌肉,皮肤,结膜 Diffracted beam with wave vector k0+g g (z )ex 2i(k p 0 g )r Summary: Bloch wave calculations 1. Solve eigenvalue equation (5.14) Y g(j), C(j) 2. Calculate matrix e(z) from g(j) from equation (5.20) Form a matrix C with C(j) as column vectors For the formulation of the matrix A, use the extinction distance defined byxG=UG/|kn|新生儿神经轴索营养不良 Infantile neuroaxonal dystrophy (Seitelberger’s disease) Set up the eigenvalue equation for a 2-beam condition, in which only the undiffracted beam and a beam G contribute. Take into account that the excitation error vanishes for the undiffracted beam. (only set it up, don‘t solve it!) Band structure calculation for the beam electron within the crystal Band structure calculation for crystal electrons (=electrons corresponding to the atoms in the crystal) are carried out by -Bloch wave method, -Density functional theory … and give an answer to: „which energies are allowed for a given wave vector?“ Coulomb potential in a ZnS slab (averaged in (110) planes) 欧洲电子显微镜介绍课件 6_Lecture_V2 Disadvantage: Kinematic diffraction theory only holds for unrealistically thin Specimens (t typically smaller than 1nm). Realistic: 5-50 nm Matrix form of equation (5.14) k k k k0 k 0 k0 k k0 Wavefunction is not continuous (Phase jump occurs at crystal surface) k k k k0 k 0 k0 k k0 The high energy approximation: Reflected waves k- are neglected Generally we want to answer: „What is the object exit plane wave function for a plane incident wave?“ or „if we describe the object exit plane wave function by a sum of plane waves running in different directions, what are the allowed wave vectors and which amplitudes and phases do the individual waves have?“ 新生儿神经轴索营养不良 Infantile neuroaxonal dystrophy (Seitelberger’s disease) Develeperment medicine child neurology 2002 Dec :44(12) 849-851 Neil Gordon 症状及体征 • 发病年龄:6月—2岁 • 运动及认知功能减退(较快) • 双侧锥体束征,但肌张力减低 • 早期视觉损害:斜视,眼震,眼动障碍 可见轴索球状小体(axonal speroids) • 除脑活检外,HE 染色多为阴性,应用非特 异酯酶染色技术 • 典型发现是球状小体,但非特异性,应结 合临床 • 电镜可见有髓及无髓纤维均受累 诊断 • 球状小体成分包括: • 高密度颗粒状物质,管状,膜状,糖原聚 3. Compute Y0(z) … Yh(z) by equation (5.22) 4. Compute wave function Y (r ) Y g (z)ex 2 i( p k 0 g )r g Homework (result used next week in the computer-session):