[Association between different obesity measurement indexes and serum C-reactive protein in adult women].

Objective: To explore the association of different obesity measurement indexes on serum C-reactive protein (CRP) in Chinese adult women. Methods: The data were obtained from baseline and follow-up surveys of the urban Breast Cancer Screening Program in Shuangliu District, Chengdu. A total of 441 adult women were included in the study. A questionnaire survey, physical examination, and laboratory testing were conducted on the subjects. Multivariate logistic regression model, two-level mixed effects logistic regression model, and restricted cubic spline method were used to investigate the linear and nonlinear correlation between different obesity measurement indexes and serum CRP in adult women. Results: For every 1 unit increase in BMI, waist circumference (WC), and adiposity, the risk of elevated serum CRP or exacerbation of chronic low-grade inflammation in adult women increased by 16.5%, 5.0%, and 11.1% (P<0.05), respectively. Both BMI and adiposity were nonlinear correlated with serum CRP. Using BMI=24.0 kg/m2 as the reference point, serum CRP level increased with the increase of BMI when BMI >24.0 kg/m2. Using adiposity=30% as the reference point, serum CRP level increased with the increase of adiposity when adiposity >30%. Conclusions: Overall, obesity reflected by BMI had the strongest association with serum CRP in adult women, followed by body fat content reflected by adiposity, and central obesity reflected by WC had the weakest association with CRP. Adult women with BMI >24.0 kg/m2 or adiposity >30% are at high risk for obesity-related inflammatory manifestations.

Novel chiral magnetic domain wall structure in Fe/Ni/Cu(001) films.

Using spin-polarized low energy electron microscopy, we discovered a new type of domain wall structure in perpendicularly magnetized Fe/Ni bilayers grown epitaxially on Cu(100). Specifically, we observed unexpected Néel-type walls with fixed chirality in the magnetic stripe phase. Furthermore, we find that the chirality of the domain walls is determined by the film growth order with the chirality being right handed in Fe/Ni bilayers and left handed in Ni/Fe bilayers, suggesting that the underlying mechanism is the Dzyaloshinskii-Moriya interaction at the film interfaces. Our observations may open a new route to control chiral spin structures using interfacial engineering in transition metal heterostructures.

Inelastic electron tunneling spectroscopy study of thin gate dielectrics.

A broad range of materials is currently being studied for possible use as the insulating layer in next generation metal-oxide-semiconductor transistors. Inelastic electron tunneling spectroscopy (IETS) has become a powerful tool to characterize both the structural and electrical properties of the resulting device structures made from these materials. IETS can address issues related to reactions and intermixing at interfaces, as well as properties related to carrier mobility, such as phonon modes and charge traps, for structures that are difficult to characterize accurately by other techniques.

Ferroelectric field effect transistors for memory applications.

The non-volatile polarization of a ferroelectric is a promising candidate for digital memory applications. Ferroelectric capacitors have been successfully integrated with silicon electronics, where the polarization state is read out by a device based on a field effect transistor configuration. Coupling the ferroelectric polarization directly to the channel of a field effect transistor is a long-standing research topic that has been difficult to realize due to the properties of the ferroelectric and the nature of the interface between the ferroelectric and the conducting channel. Here, we report on the fabrication and characterization of two promising capacitor-less memory architectures.

Electron energy-loss spectroscopy study of thin film hafnium aluminates for novel gate dielectrics.

We have used conventional high-resolution transmission electron microscopy and electron energy-loss spectroscopy (EELS) in scanning transmission electron microscopy to investigate the microstructure and electronic structure of hafnia-based thin films doped with small amounts (6.8 at.%) of Al grown on (001) Si. The as-deposited film is amorphous with a very thin (approximately 0.5 nm) interfacial SiOx layer. The film partially crystallizes after annealing at 700 degrees C and the interfacial SiO2-like layer increases in thickness by oxygen diffusion through the Hf-aluminate layer and oxidation of the silicon substrate. Oxygen K-edge EELS fine-structures are analysed for both films and interpreted in the context of the films' microstructure. We also discuss valence electron energy-loss spectra of these ultrathin films.

Organization of the medial pulvinar nucleus in the macaque.

BACKGROUND: The medial pulvinar appears to subserve the integration of associative cortical information and projects to visuomotor-related cortex. In contrast to the other pulvinar subdivisions, the medial pulvinar is a polymodal structure. Therefore, we studied the structural organization of the medial pulvinar to determine how it differs from the surrounding unimodal nuclei. METHODS: Nissl-stained sections were examined to determine the boundaries of, and the distribution of neuronal sizes within, the medial pulvinar. In addition, Golgi-impregnated neurons were examined and drawn for analysis. Only rhesus monkey specimens were used, and the material had been prepared previously for other studies. RESULTS: Projection neurons have round to oval somata and moderate numbers of primary dendrites that extend for short distances before branching into many secondary branches. Two variations of projection neurons (P1 and P2) were distinguished on the basis of the diameters of their dendritic tree. Both varieties have short dendrites that radiate in all directions. They differ in that P2 cells have longer second tier dendrites than P1 cells. Three types of local circuit neurons, tufted, radiating and varicose, were distinguished on the basis of their dendritic morphology. Four types of afferent fibers were identified. Type 1 afferents form cone-shape terminal arbors. Type 2 afferents are similar to those reported for retinal or cortical terminals. Type 3 afferents are of medium thickness and of an unknown origin. Type 4 afferents are thin and have small varicosities consistent with previously described cortical afferents. Afferent fibers are predominantly oriented along the mediolateral axis of the nucleus. We observed putative contacts between some afferents and local circuit neurons and between local circuit neurons and projection neurons. CONCLUSIONS: Medial pulvinar neurons are generally smaller and rounder than those found in the adjacent pulvinar nuclei. These results provide additional evidence for structural distinctions between thalamic nuclei having different functions. However, the observed differences are subtle. In addition, the data in this report provide morphological evidence that cortical signals are likely to be integrated by means of the circuitry located within the nucleus.

Organization of the zona incerta in the macaque: an electron microscopic study.

BACKGROUND: The zona incerta (ZI) receives projections from many telencephalic and brainstem structures. On the basis of its connectivity and physiology, this nucleus has been implicated in the control of saccadic eye movements. Because of the complexity of its afferent signals and its simple efferent signal, there must be much local interaction within the ZI to integrate these various afferents. The purpose of this study was to investigate, at the ultrastructural level, whether the ZI contains the anatomical substrata which could subserve the control of eye movements. METHODS: Blocks of tissue from the ZI of macaque monkeys were prepared for electron microscopy using standard techniques. Some of these animals were taken specifically for electron microscopy. Others had received injections of tracer substances and were prepared for electron microscopy subsequent to tracer visualization. RESULTS: Cell bodies of medium-large neurons were found in our preparations. They have large nucleoli and relatively small volumes of karyoplasm. Cell bodies and dendrites of all sizes have many synaptic contacts. Three types of synaptic profiles were found, designated Types 1, 2, and 3. Type 1 profiles are symmetrical and contact cell bodies and small dendrites. Type 2 profiles are thought to be presynaptic dendrites and may have symmetrical or asymmetrical contacts. Type 3 profiles are asymmetrical and primarily contact small dendrites. Many synapses contacted vesicle-containing profiles. In some cases, it was clear that these profiles participated in serial synapses on presumptive presynaptic dendrites. Other profiles appeared to be axoaxonic contacts. CONCLUSIONS: Afferent and efferent signals are likely to be modulated extensively within the ZI. Therefore, there needs to be complex interactions between neuronal elements of the ZI and its afferents. This study demonstrates that this nucleus possesses the structural substrata to subserve diverse roles, such as the gating of saccadic eye movements.

Saccade-related omnivectoral pause neurons in the primate zona incerta.

The zona incerta contains GABAergic neurons projecting directly on to collicular efferent neurons. This study examined the physiological characteristics of incertal neurons and their relationship to saccades. Cells in the zona incerta have moderate rates of activity and pause during saccades. These pauses begin prior to the start of saccades and activity resumes after the end of saccades in all directions and for all amplitudes. This perisaccadic pause is positively correlated with the duration of the saccade such that the longer the saccade is, the longer a pause is observed. These physiological data, in conjunction with anatomical observations, suggest that the zona incerta might normally function by inhibiting the superior colliculus and then by disinhibiting the superior colliculus for saccades.

Cytoarchitecture of the substantia nigra pars lateralis in the opossum (Didelphis virginiana): a correlated light and electron microscopic study.

BACKGROUND: The substantia nigra has been divided into three subdivisions. However, the cytoarchitecture of one of these subdivisions, the pars lateralis (SNl), has not been previously examined in detail at the light and electron microscopic levels in any species. In the adult opossum, the three nigral subdivisions can be easily distinguished as distinct, rostrocaudally oriented cell groups separated by neuron-free zones. Thus it was possible to determine the boundaries of the SNl unambiguously. This report covers the results of an examination of the morphology and organization of the SNl in the opossum. METHODS: Material from 13 opossums was used for this study. Eight of the animals had been previously stained for Nissl substance (n = 4) or impregnated by the Golgi technique (n = 4). The remaining five animals were prepared for electron microscopic studies using standard procedures. RESULTS: Two cell types were identified on the basis of morphological differences, small and medium-large neurons. Small neurons (10-18 microns long axis) have large nuclei with moderate amounts of heterochromatin and a thin rim of cytoplasm. They have long (up to 500 microns), spine-free dendrites. Medium-large neurons (18-54 microns long axis) have rounded nuclei with electron-lucent nucleoplasm. Few indentations of the nuclear envelope were observed. The surrounding cytoplasm has dense arrays of organelles. Nissl bodies are particularly prominent in the form of pyramids with their bases at juxtanuclear positions and their apices directed toward emerging dendrites. Dendrites of medium-large neurons are long (some > 1 mm in length), are primarily oriented in the frontal plane, and extend along the dorsal surface of or into the cerebral peduncle. Some cells have dendrites that are moderately spinous, whereas other neurons possess sparsely spinous dendrites. Relatively few synaptic profiles are observed to contact somata and proximal dendrites. CONCLUSION: This report provides added morphological support for the idea that the SNl is a distinct subdivision of the substantia nigra, a distinction previously made on the basis of the physiologically characterized relationship between the lateral substantia nigra and orienting behaviors and seizure-related function.

Organization of the zona incerta in the macaque: a Nissl and Golgi study.

The zona incerta has been implicated in the control of the initiation of saccadic eye movements in the primate. Complex interactions within the zona incerta must take place to integrate its varied inputs and to produce a coherent efferent signal in order for this function to occur. However, whether the anatomical substrates exist within the zona incerta to allow this integration to take place has not been established. The zona incerta in monkeys (Macaca mulatta) was examined in frontally, horizontally, and sagittally sectioned preparations stained for Nissl, myelinated fibers, or cytochrome oxidase, or impregnated by the Golgi technique. This nucleus can be separated into dorsal and ventral laminae on the basis of staining and morphological differences between these two subdivisions. Neurons are more densely packed, more darkly stained, and larger in the ventral lamina. In addition, the neuropil of the ventral lamina is much more intensely stained after cytochrome oxidase histochemistry. Two neuronal types, principal cells and interneurons, were identified on the basis of neuronal cell body, dendritic, and axonal features in Golgi-impregnated preparations. Principal cells have fusiform or polygonal somata (long axis from 18 to 40 microns) and dendrites that extend for up to 750 microns within the lamina in which the cell bodies are located. Putative local interneurons have small (12-16 microns), round or oval cell bodies with wavy dendrites (up to 400 microns). Numerous multilobed appendages and axon-like processes originate from these dendrites and make apparent contacts with other interneurons or with dendrites of principal cells. Dendrites of most neurons in both laminae are oriented preferentially along the principal axis, dorsolateral-to-ventromedial, of the nucleus. Therefore, within the limits of light microscopy, the zona incerta appears to possess the morphological heterogeneity to form complex intrinsic interactions. These interactions are hypothesized to form the integrative substrate for the large array of incertal inputs that are utilized to produce an efferent signal involved in the initiation of saccadic eye movements.

Superior colliculus neurons mediate the dynamic characteristics of saccades.

1. The locus of activity within the superior colliculus (SC) is related to the desired displacement of the eye. Current hypotheses suggest that the location of this locus of activity determines the amplitude of the saccade and that the level of activity at this locus determines eye velocity. We present evidence that suggests that, although the locus determines the amplitude of the saccade, the level of activity in the colliculus encodes dynamic motor error (the difference between desired and current eye displacement). 2. We categorized 86 neurons in the intermediate and deep layers of the superior colliculus of two rhesus monkeys by their activity in relation to the end of saccadic eye movements. In 36% of the cells (n = 31), activity was completely cut off by the end of the saccade (clipped cells). For 53% of cells (n = 46), the major burst of activity ceased by the end of the saccade, but activity continued for 30-100 ms after the end of the movement (partially clipped cells). The remaining 10% of the cells (n = 9) had no clear burst of activity (unclipped cells) but rather had activity that increased gradually before the saccade and then slowly decreased for up to 100 ms after the saccade. These categories were part of a continuum of cell types rather than discrete classes of cells. 3. We first determined whether this new categorization of cells revealed a special relation between the discharge of clipped and partially clipped cells and saccadic amplitude and peak velocity. As expected, we found a steady increase in spike count as saccadic amplitude increased up to the center of the movement field, and an increase in peak spike discharge as peak velocity increased up to a maximum radial eye velocity. Variability in the cell discharge was substantially greater than the variability of saccadic amplitude or peak velocity. We concluded that these single point or averaged measures did not reveal any new functional relationship of these cells. 4. We then examined the relationship of the temporal pattern of discharge of clipped and partially clipped cells to instantaneous changes in radial error and radial velocity. There was a monotonic decay in spike discharge with declining radial error. In contrast, there was a complex, multivalued relationship between spike discharge and radial velocity; collicular cells produced two different values of spike discharge for the same velocity, one during acceleration and the other during deceleration of the eye during a saccade.(ABSTRACT TRUNCATED AT 400 WORDS)

Location of saccade-related neurons in the macaque superior colliculus.

The locations of saccade-related neurons were studied in the superior colliculi of two adult rhesus monkeys (Macaca mulatta) by placing marking lesions at the sites of physiologically characterized cells and comparing these histologically identified sites with the collicular laminae and acetylcholinesterase (AChE)-rich patches. Three major conclusions were drawn on the basis of 39 histologically identified sites at which saccade-related neurons were recorded. First, saccade-related neurons were distributed from the ventral half of the optic layer through the deep gray layer, and were most concentrated in the intermediate gray and white layers. Second, there was a clear relationship between the discharge characteristics of these saccade-related neurons and the depths at which they were found. Neurons having presaccadic bursts, defined as clipped and partially-clipped, tended to be encountered more dorsally, and neurons that did not have bursts (unclipped) were encountered more ventrally. Although cells having different discharge characteristics seemed to be organized along a dorsoventral axis, there was no compelling evidence that these properties were specified by their laminar locations. Third, there was no clear correlation between the locations of saccade-related neurons and the distribution of individual AChE-rich patches. Saccade-related cells were found both in the caudal superior colliculus where patches were located and in the rostral superior colliculus where patches were not found; both within and between the two tiers of AChE-rich patches in the caudal superior colliculus; and both within and between individual AChE-rich patches. However, the depth-level at which saccade-related neurons occurred generally matched the region bounded by the two tiers of AChE-rich patches in the intermediate and deep layers, and the dorsal and ventral extent of saccade-related neurons was the same as that of the AChE-rich patches.

Intermediate and deep layers of the macaque superior colliculus: a Golgi study.

We studied the intermediate and deep layers of the macaque superior colliculus by means of the Golgi technique in an attempt to better understand the structural features of this important oculomotor center. For this study, we examined the optic (stratum opticum, SO), intermediate gray (stratum griseum intermedium, SGI), intermediate white (stratum album intermedium, SAI), and deep gray (stratum griseum profundum, SGP) layers. These are the four layers in which neurons having saccade-related activity are localized. We identified eight neuronal types on the basis of differences in somatic and dendritic morphologies: large multipolar neurons (Type I); large pyramidal neurons (Type II); large fusiform neurons (Type III); medium fusiform neurons with spiny, radially oriented dendrites (Type IV); medium round neurons with fan-shaped dendritic trees (Type V); medium stellate neurons with varicose dendrites (Type VI); medium multipolar neurons with robust, spiny dendrites (Type VII); and local interneurons (Type VIII). Most neuronal types possessed features that are homologous to presynaptic dendritic features in other brain centers. With the exception of the medium stellate neurons (Type VI), which are aspinous, and the local interneurons (Type VIII), which are sparsely spinous, all other types had a moderate number of spines on their dendrites. Dendrites that terminated in the optic layer had specializations not observed elsewhere, suggesting that these tips may sample a tectal afferent that is not present in the more ventral layers. These eight types comprise all the neuronal morphologies observed in a large number of Golgi-impregnated macaque brains (n = 50). We suggest that they represent the full range of neuron types in the saccade-related layers of the macaque tectum.

Identification of the substantia nigra pars lateralis in the macaque using cytochrome oxidase and fiber stains.

Classically, the substantia nigra is divided into three subdivisions, the pars compacta, the pars reticulata, and the pars lateralis. The purpose of the present study was to develop methods for routine identification of the non-compacta subdivisions in the macaque monkey. First, the pars reticulata and pars lateralis were identified based on their Nissl features. Second, nearby cytochrome oxidase and Gallyas fiber stained sections were examined for these two subdivisions. In both stains, a dorsolateral region could be identified to contain large fiber bundles. This region is coextensive with the pars lateralis as identified in Nissl-stained preparations. Lastly, we examined the complete extent of the pars lateralis using the cytochrome oxidase procedure. We conclude that in the macaque monkey the pars lateralis can be identified as a distinct nigral subdivision by using cytochrome oxidase and fiber staining techniques.

Superior colliculus neurons provide the saccadic motor error signal.

Studies of the intermediate layers of the superior colliculus have suggested that it provides a desired change in eye position signal (delta E) for the generation of saccadic eye movements. Recent evidence, however, has shown that some neurons in these layers may be related to the velocity of saccades. We present single cell recordings from the intermediate layers of monkey superior colliculus that are consistent with the hypothesis that many superior colliculus neurons provide instead a motor error signal, em. Our hypothesis about the function of these cells places them inside the local feedback loop controlling the waveform of the saccade.