Electron microscopic studies of medullary synaptic inputs to vasopressin-containing neurons in the hypothalamic paraventricular nucleus

We have observed the ascending projections from the lower brain stem to the magnocellular vasopressin-like immunoreactive (VP-LI) neurosecretory neurons in the paraventricular nucleus (PVN) using electron microscopy. The tissues were prepared by a double labeling technique combining anterograde tracing after iontophoretic injection of wheat germ agglutinin-coupled horseradish peroxidase (WGA-HRP) in the A1 group (lateral reticular nucleus in the medulla oblongata) with VP immunocytochemistry. Both the WGA-HRP-labeled and the unlabeled axon terminals made synaptic contacts with VP-LI cell bodies and processes in the PVN. This indicates a direct synaptic influence of medullary A1 group on the secretory activity of the VP-containing neurons in the hypothalamic paraventricular nucleus.     

老龄大鼠脑缺血再灌注海马神经元iNOS的表达及超微结构改变

目的：观察老年大鼠脑缺血再灌注后海马神经元诱导型一氧化氮合酶（induced nitric oxide synthase iNOS）的表达及超微结构变化。方法：建立老年大鼠不完全性全脑缺血动物模型,应用免疫组织化学染色和透射电镜,观察海马神经元iNOS的表达及超微结构变化。结果：缺血30min后再灌注24h组海马神经元iNOS活性显著升高;缺血30min再灌注21h和48h组中量表达;假手术组、缺血30min即刻取材、再灌注1h、6h、96h组iNOS几乎无表达;再灌注超过48h组海马神经元损伤较重。结论：NO是脑缺血后神经元迟发性死亡的重要因素之一。     

正中隆起室管膜面赘生物及其形成过程的电镜观察

在正常SD雄性大鼠（2周龄-27月龄）第三脑室底正中隆起前缘附近,本研究用扫描电镜观察到有呈圆柱状中空赘生物出现。该赘生物可分为基底部、体部及末梢部,其直径为2-10μm,长度为2-230μm。通过观察该赘生物的形成过程,有理由认为它是室管膜细胞过度增生所致,但与室管膜瘤不同。     

Fine structure of the dielectric-function spectrum in diamond

The spectra of the complete set of optical functions for three different diamond samples were calculated for the range of 0–32 eV. Calculations were based on the features of experimental reflection spectra; the Kramers-Kronig method was used. The features of the optical-function spectra and their distinctions for the three samples were analyzed. The method of the combined Argand diagrams was used to decompose for the first time the dielectric-function spectra into elementary components. The energies of these components and the oscillator strengths were determined. The structure of the components was compared to the structures of theoretical spectra of permittivity and the expected spectra of band-to-band transitions. Good agreement between the results of this study and the theory was obtained.     

粘土胶老化后性能与结构的研究

由于炭黑价格的不断上涨 ,人们一直寻找价廉的非炭黑补强填料。红粘土可替代ＨＡＦ、ＧＰＦ和ＳＲＦ等炭黑制成橡胶制品[1] 。但粘土胶耐老化性能较差 ,对于其宏观性能与微观结构的关系尚未见报道。本文研究了粘土胶经热氧、光氧和臭氧老化后结构与性能的变化。1　实验将粘土试样与天然胶乳经凝固、压片、干燥等步骤制成粘土胶试样。粘土胶按国家标准进行热氧老化 1 0 0℃× 36ｈ ;氧老化分 30ｈ和 45ｈ及臭氧老化。进行性能测试 ,结构研究在ＰｈｉｌｉｐｓＸＬ 30型扫描电镜上完成。2　结果与讨论粘土胶的力学性能见表 1。表 1　粘土胶老化…     

Fine structure and mineral components of primary calculi in some human prostates

The fine structure of prostatic calculi has not been elucidated yet, although the chemical components were reported in detail. We studied the primary or endogenous calculi removed from eight human prostates by secondary scanning electron microscopy, backscattered electron imaging, energy-dispersive X-ray microanalysis and X-ray diffraction. The primary calculi containing Mg, Zn and S, besides Ca and P were basically classified into four stone groups (I-IV) by fine structure and mineral components. Stone I had the core deposits of calcospherites showing concentric rings and the laminated deposits concentrically around the core. Their deposits were identified as apatite. Stone II was occupied with the calcospherite deposits of apatite although the stone growth showed a rough concentric formation. Stone III contained the core of calcospherites and concentric laminated structures, similar to a smaller type of group I, whereas the wider peripheral region was deposited with needle-like structures, identified as calcium oxalates. Stone IV had the core deposits containing small hexahedral structures, identified as whitlockite, which were surrounded with several incompletely concentric laminated bands of apatite. Whitlockite crystals were also found between the fused large calculi. The initial and formative calculi were basically observed as the deposition of mineralizing spherical structures suggesting variously sized corpora amylaceous bodies. Thus, the primary prostatic calculi of stones I-III will begin from the mineralization of amylaceous bodies as a core, while the organic substances, which form stone IV, might be derived from the simple precipitation of prostatic secretion.     

Fine structure and Zeeman effect of the excited state of the green emitting copper centre in zinc oxide

In the excitation spectrum of the green emission band of ZnO:Cu crystals, zero phonon lines have been detected for the first time. In the liquid-helium temperature range, a line with Δ = 2 cm⁻¹ at λ = 433.5 nm coincides with the well-known zero-phonon line of the emission. Additional lines are located at 432.2 and 431.4 nm. In a distance of 525 cm⁻¹ from these zero-phonon lines, phonon satellites superpose on the low-energy part of the broad excitation band. On its high-energy slope pronounced structures appear in the excitonic region. With selected highly-doped crystals, the new zero-phonon lines could also be detected in absorption.Zeeman experiments produce anisotropic splittings of the common ground state of all three lines with g = 0.7 ± 0.1 and g = 1.5 ± 0.1 which are approximately the values known from emission. Different anisotropic g-factors around g = 2 are derived for the terminal states of the absorption lines.The experimental data are compatible with a model of the investigated centre in which the ground state is Cu²⁺ and the excited state is a Cu⁺ with a loosely bound hole: (Cu⁺)⁺ [3]. As to the position of the impurity levels within the forbidden gap, still two possibilities exist: the excited hole could either be localized near the oxygen neighbours so that a depth of some tenth of an eV results, or effective-mass-like states could be involved in a distance of only a few meV above the top of the valence band.     

Discontinuous capillary segments in the extensor digitorum longus muscle of aged BUF/Mna rats

We examined the structural changes of capillaries in the extensor digitorum longus muscle of aged (25 months) male BUF/Mna rats, which caused severe muscle weakness of hind legs during aging. The aged muscle mostly consisted of bundles of muscle fibres 15-35 microm in diameter (type 1). In some small areas, however, muscle bundles contained small muscle fibres mainly 15-25 microm in diameter (type 2), possibly indicating that these small fibres are in the course of regeneration after necrosis. Examination of serial ultrathin sections revealed some remarkable changes of capillaries in the type 2 muscle bundle. In some capillaries, the vascular lumen became discontinuous by several close contacts of opposed endothelial cells in their course, forming plural closed vascular segments. Moreover, a solitary endothelial cell was often observed within a scaffold of basal lamina, which remained after destruction of endothelial cells. The segmentation of capillaries and the occurrence of the scaffolds of basal laminae are considered to indicate the degenerative process of capillaries. In some instances, on the other hand, endothelial cells closely apposed each other with no vascular lumen for distances of up to 100 microm, and some capillaries had a narrow vascular lumen (1-3 microm diameter) for a long distance (approximately 300 microm), probably indicating that these structures are in the course of regenerating capillaries to remodel the capillary networks around the muscle fibres. Pericytic processes circularly arranged outside the endothelium at the slit-like and narrow vascular lumen, like hoops, possibly preventing the rupture of the newly-formed vascular lumen from the increased blood flow and/or blood pressure. In addition, the occasional occurrence of capillaries with fenestrations may participate to increase the supply of nutrients and oxygen to the regenerating muscle fibres. The present findings suggest that the capillary networks in the extensor digitorum longus muscle of aged BUF/Mna rats are remodelled following the regeneration of muscle fibres after necrosis, and that on occasion, neighbouring endothelial cells may closely contact with each other both in the degenerative and regenerative processes of capillaries.     

激光穴位照射对大鼠束旁核单位伤害性反应的影响

48个束旁核痛敏单位在激光穴位照射后，有16个单位（33．33％）的痛敏放电被明显抑制，13个单位（27．1％）的痛敏放电受到部分抑制；其余19个单位（39．6%）的痛敏放电在激光照射前后未见明显变化，在4个激光照射有明显抑制效应的单位，注射吗啡受体阻断剂纳络酮后，有3个单位的抑制效应被明显削弱，另外1个单位的抑制效应依然存在。在3个痛敏放电不受激光照射影响的单位，注射吗啡后只有1个单位的痛敏放电受到明显抑制。     

Interactions of "ultra-low" doses of naltrexone and morphine in mature and young male and female rats

Sex and age influence morphine analgesia in humans and animals. Mature rats show greater morphine analgesia in males than in females. Ultra-low doses of naltrexone enhance morphine analgesia. In mature rats (18-22 weeks), naltrexone (0.002-2.0 mg/kg)-morphine (2 mg/kg) cotreatment enhanced morphine analgesia in females, an effect inversely related to naltrexone dose. Conversely, in mature male rats, naltrexone tended to decrease morphine analgesia with increasing dose. In young rats (8-10 weeks), morphine analgesia was unrelated to sex and in both sexes the naltrexone-morphine interaction was negligible. These data show that dose, age, and sex alter the naltrexone-morphine interaction in rats.     

Novel muscle spindles containing muscle fibers devoid of sensory innervation in the extensor digitorum longus muscle of aged rats

We examined the structural features of muscle spindles at the equatorial and juxtaequatorial regions in the extensor digitorum longus muscle of adult (12 months) and aged (25 months) rats. In aged muscle spindles, the lamellated layers of the spindle capsule were a little increased in number compared to those in the adult ones. Two novel muscle spindles were observed in the aged muscle. In one muscle spindle, the spindle capsule contained four thin intrafusal muscle fibers invested by the inner capsule and two muscle fibers between the layers of the spindle capsule. Serial semithin sections revealed that the latter lacked the investment of the spindle capsule at the polar region. The other muscle spindle contained four intrafusal muscle fibers: two thin sensory-innervated muscle fibers invested by the inner capsule and two thick muscle fibers similar in structural features to neighboring extrafusal muscle fibers and lacking sensory innervation within the wide periaxial space. These findings suggest that two muscle fibers between the layers of the spindle capsule may be invested by the newly formed capsular cells during aging, while two thick fibers within the periaxial space may fail to receive the sensory innervation during the early development and follow the course of extrafusal fiber differentiation.     

Changes in the supramolecular structure of chromatin and pepsinogen synthesis in the gastric mucosa of rats undergoing N-methyl-N'-nitro-N-nitrosoguanidine-induced carcinogenesis

A model of gastric tumour induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in rats made it possible to detect essential alterations of chromatin-DNA-protein complexes, that is a weakening of the DNA-protein linkage. The changes appear at early stages of carcinogenesis and persist in induced adenocarcinomas of the stomach. Simultaneously an inhibition was established in pepsinogen synthesis during MNNG carcinogenesis, which reflects a damage in expression of functionally important genetic information. This fact shows a molecular-genetic connection between the process of the gastric mucosa malignization and a disturbance of physiologically important tissue-specific gene functions.     

A sulphur matrix complex,elastic fibril composed of a fine core of amorphous elastin and microfibrils was largely accumulated in the aortic intima of aged rats

We examined elastic fibrils in the aortic intima of aged rats with elastin staining, elastase digestion and X-ray microanalysis. The innermost elastic lamina, heavily stained by a brief treatment with azure II-toluidine blue without heating, was thin and fragmented, and an amorphous substance that stained weakly to moderately was accumulated in the thick subendothelial space of 26-28-month-old rat aortas. The substance was always present in the intimas; to a large extent in the aged rats but rarely in 5-month-old rats, and disappeared after digestion with elastase. The amorphous substance was identified as elastic fibrils approximately 0.1-0.2 microm in diameter under an electron microscope with tannic acid-uranyl acetate/lead citrate staining. Elastase digestion revealed that elastic fibrils were composed of a number of microfibrils, which were 10-12 nm in diameter, in and around a fine core of amorphous elastin. X-ray microanalysis revealed a clear peak of sulphur in the elastic fibrils.     

Long term noise measurements and median time to failure test for the characterization of electromigration in metal lines

The high sensitivity, which can be obtained by means of noise measurements, is especially useful for the characterization of the early stages of the electromigration phenomenon. In addition, with the noise being strictly dependent on the sample microstructure, it is obvious to expect that it can be used for monitoring the different stages of the degradation process. In this paper, the results obtained by performing noise measurements during lifetime tests are presented, with the aim of investigating the evolution of the electromigration noise during the entire life of the sample. Conventional Median Time to Failure (MTF) tests have been performed on samples belonging to the same set. One of the aims of this work is to investigate the possibility of establishing a new failure criterion based on noise measurement capable of providing, in a shorter time, the same type of information normally obtained from MTF tests.     

Effect of pressure and temperature on electronic structure of GaN in the zinc-blende structure

The effect of the hydrostatic pressure and the temperature on the electronic structure in GaN semiconductor has been calculated using the local empirical pseudopotential method. The variation of the direct and indirect energy gaps with the pressure up to 120 kbar and with the temperature up to 500 K has been done. The calculated fundamental energy gap at different pressures and different temperatures are calculated and compared with the available experimental data which show excellent agreement. The effect of pressure and temperature on the refractive index of the considered materials has also been studied.     

Multiscale entropy analysis of pulse wave velocity for assessing atherosclerosis in the aged and diabetic

This study proposed a dynamic pulse wave velocity (PWV)-based biomedical parameter in assessing the degree of atherosclerosis for the aged and diabetic populations. Totally, 91 subjects were recruited from a single medical institution between July 2009 and October 2010. The subjects were divided into four groups: young healthy adults (Group 1, n = 22), healthy upper middle-aged adults (Group 2, n = 28), type 2 diabetics with satisfactory blood sugar control (Group 3, n = 21), and unsatisfactory blood sugar control (Group 4, n = 20). A self-developed six-channel electrocardiography (ECG)-PWV-based equipment was used to acquire 1000 successive recordings of PWV(foot) values within 30 min. The data, thus, obtained were analyzed with multiscale entropy (MSE). Large-scale MSE index (MEI(LS)) was chosen as the assessment parameter. Not only did MEI(LS) successfully differentiate between subjects in Groups 1 and 2, but it also showed a significant difference between Groups 3 and 4. Compared with the conventional parameter of PWV(foot) and MEI on R-R interval [i.e., MEI(RRI)] in evaluating the degree of atherosclerotic change, the dynamic parameter, MEI(LS) (PWV), could better reflect the impact of age and blood sugar control on the progression of atherosclerosis.     

试论美术教学中计算机辅助设计与艺术设计的课程整合

伴随近些年我国社会经济发展速度的提升和科学技术水平的提高,计算机等辅助设备应用范围的不断拓展,使得人民群众日常的生产生活受到了极大的影响,其工作和生活质量得到了极大的改善。艺术设计作为美术教学门类中的重要组成,在计算机技术不断发展和教育教学改革不断加深的今天,美术教师要想提高其艺术设计的教学水平,应该借助计算机技术的相关功能。对此,文章以美术教学为切入点,通过对计算机辅助设计概念的分析,就该辅助设计在艺术设计教学中具体的应用情况进行研究。     

软件工程中的结构建设及需求分析

软件工程飞速发展,被应用于各个行业。对软件工程的结构建设是对软件开发的重要过程,也是保障其应用的重要方式。而完善结构建设的重要过程,是将其应用于实际,应当从了解需求从而分析开始。文章描述了软件工程中的结构建设的具体流程和方式,并且通过具体案例分析了需求的实施方案。     

The structure and motion of the self-interstitial in diamond

We have made self-consistent semi-empirical molecular orbital calculations for various possible self-interstitial geometries in diamond, both with and without lattice distortion. Total energies are obtained, not merely the sum of one-electron eigenvalues. The results show that the (100) split interstitial has the lowest formation energy, not the cubic, hexagonal or bond-centred forms favour previously.The nature of the interstitial does not support the local heating model of enhanced diffusion in the presence of recombination or ionisation. A Bourgoin-Corbett mechanism involving negative hexagonal and neutral split interstitials is possible, but the apparent stability of the negative hexagonal interstitial may be an artefact of the calculation. We suggest a local excitation model is appropriate in fourfold-coordinated semiconductors.