SEARCH · Search PubMed

Results for “ARCHITECTURE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,207 records · Page 67Linked to original sources

PubMed1999

Walking through a maze alters the architecture of sleep.

Human and animal studies imply that sleep is a critical period for consolidation of recent memories. Whereas the majority of researchers focussed on the procedural learning, the present human study concerns how storing of spatial information and episodic memory are linked to sleep stages. Two city mazes, a simple and a complex one, were created by means of a computer program. Local aspects of these mazes appeared as street scenes on a TV-screen. Our subjects sat in front of the screen and manoeuvered through the maze by the help of a three-button PC mouse. Thus, each subject took a 'mental walk' through an imaginary city. The task was to find various end-points and to find the way back to the starting point. Subjects of two experimental groups 'walked' through either the simple or complex city maze for eight hours. Afterwards the subjects slept in our laboratory, where their sleep stages could be measured polygraphically. Subjects who had explored the simple maze showed considerable alteration in sleep architecture. They remained significantly longer in sleep Stage 2 than subjects who had explored the complex maze. Moreover, with successful orientation in the simple maze sleep stages occurred aperiodically, whereas walking through the complex maze was associated with sleep stages in accordance with ultradian cycles, as observed in a control group. Compared to subjects of the control group who had experienced neither maze, the subjects of both experimental groups had significantly enhanced EEG sleep spindle activities. Alteration in temporal architecture of sleep and selective prolongation of sleep Stage 2 following spatial orientation point to a functional linkage between cognitive mapping of space and sleep Stage 2 with enhanced EEG spindle activity.

Activity Cycles↗

PubMed1989

The blood vascular architecture of the salamander external gill: a scanning electron microscopic study of corrosion casts.

The blood vascular architecture in three-paired external gills of salamander tadpoles, Hynobius dunni Tago, was demonstrated with special reference to metamorphosis by scanning electron microscopy of vascular corrosion casts. In the fully developed gill, each of the three-paired afferent branchial arteries gave off secondary afferent filament arterioles. The afferent filament arteriole drained toward the efferent filament arteriole, forming the loop at the posterior extremity of the gill filament. The branched capillaries from the afferent filament arteriole formed two plates of respiratory capillary networks with irregular honeycomb-shaped meshes. In addition, there were non-respiratory shunts as bypass of the blood circulation between the afferent and efferent branchial arteries without branching filament arterioles. Furthermore, the deep venous plexus and subepithelial capillary plexus were seen around each efferent branchial artery. The filament central venule in the central part of the filament merged into the venous plexus. Nutritive capillaries branched from efferent branchial arteries also drained toward the venous plexus. Such general vascular architecture is simpler than that of the fish. During metamorphosis, the pattern of the vascular distribution, especially filament net capillaries became irregular, and then markedly tortuous or convoluted blood vessels occurred in the absorbing gill. At the metamorphic climax, the capillary network practically disappeared in the remnant of the gill but the bypass shunt as a non-respiratory artery remained almost unchanged.

Animals↗

PubMed1992

Stereo architecture of the lamina propria in the mouse laryngopharynx in scanning electron microscopy.

In the ventral wall of the mouse laryngopharynx, a fairly large number of the epithelial papillae containing taste bud (provisionally denominated the pharyngeal papillae) were observed. The NaOH cellmaceration method was applied in order to demonstrate the stereo architecture of the connective tissue papillae (CTP) of the pharyngeal papillae. The CTP appeared as a cylindrical wall surrounding a round depression, and consisted of a delicate meshwork of collagen fibrils. It is suggested that the CTP constitute the skeletal framework of the pharyngeal papillae and that the round depression corresponds to the site of taste bud. Furthermore, the collagen fibrillar architecture in the extrapapillary region appeared to be arranged to meet specific functional needs. That is, in the rostral end of the laryngopharynx, the collagen fibrils ran solitarily to form a coarse meshwork and seemed to allow the epithelium a certain degree of freedom of motion in swallowing. On the other hand, in the caudal part the fibrils concentrated into the thick bundles of the fibers running side by side along the long axis of the laryngopharynx and, therefore, appeared to play an important role in resisting the excessive stretching force.

Animals↗

PubMed1995

Architecture of the lateral line organ of the sea eel Conger myriaster.

The architecture of trunk canal neuromasts of the Japanese sea eel was morphologically examined. A fluid-filled canal is connected with the outside by horn-shaped tubules whose outer openings are seen as pores, which are variable in shape and very narrow as compared to the canal diameter. A projection shaped like a semilunar valve hangs over each neuromast from the opposite wall. The total number of hair cells in a canal neuromast was 500 to 600, about fivefold more numerous than that in a superficial neuromast. Two groups of hair cells, rostrally and caudally oriented, are nearly equal in number. The observed architectures are thought to favor efficient detection of the flow of water within the canal. These findings substantiate the current understanding that each canal neuromast encodes the pressure difference between two adjacent pores.

Animals↗

PubMed1996

Three dimensional architecture of collagen fibrils in the corpus cavernosum of the crab-eating monkey.

The three-dimensional architecture of the collagen fibrils in the corpus cavernosum of the crab-eating monkey was studied by scanning electron microscope, after digestion of cellular and some extracellular elements by NaOH. The tunica was made up of undulating bundles of collagen fibrils which were arranged in inner circular, middle intermingled and outer longitudinal layers. The trabecula appeared as numerous cylindrical tubes which had once accommodated individual smooth muscle fibers. The outer surface of the trabecula was covered with a sheath woven from twisting bundles of collagen fibrils. These architectural features of the collagen fibrils seem to be related to fluctuations in the diameter and shape of the corpus during erection and detumescence.

Animals↗

PubMed1996

Disrupted collagen architecture in the crystal structure of a triple-helical peptide with a Gly-->Ala substitution.

The crystal structure of the collagen-based peptide (Pro-Hyp-Gly)4-Pro-Hyp-Ala-(Pro-Hyp-Gly)5 has provided for the first time a highly detailed picture of the architectural elements that come into play in the collagen triple helix. The center of the molecule, which harbors a Gly-->Ala substitution, shows subtle conformational changes that result in a local untwisting of the triple helix. The characteristic hydrogen bonding pattern of collagen triple helices is replaced by interstitial water bridges. These effects may be relevant to the diseased states derived from Gly-->X mutations in collagens. The possible implications of this disrupted architecture for collagen assemblies are discussed.

Alanine↗

PubMed1997

Fractal characteristics of tumor vascular architecture during tumor growth and regression.

OBJECTIVE: Tumor vascular networks are different from normal vascular networks, but the mechanisms underlying these differences are not known. Understanding these mechanisms may be the key to improving the efficacy of treatment of solid tumors. METHODS: We studied the fractal characteristics of two-dimensional normal and tumor vascular networks grown in a murine dorsal chamber preparation and imaged with an intravital microscopy station. RESULTS: During tumor growth and regression, the vasculature in the tumor has scaling characteristics that reflect the changing state of the tissue. Growing tumors show vascular networks that progressively deviate from their normal pattern, in which they seem to follow diffusion-limited aggregation to a pathological condition in which they display scaling similar to percolation clusters near the percolation threshold. The percolation-like scaling indicates that the key determinants of tumor vascular architecture are local substrate properties rather than gradients of a diffusing substance such as an angiogenic growth factor. During tumor regression the fractal characteristics of the vasculature return to an intermediate between those of growing tumors and those of healthy tissues. Previous studies have shown that percolation-like scaling generally inhibits transport. CONCLUSIONS: In the present context, the percolation-like nature of tumor vasculature implies that tumor vascular networks possess inherent architectural obstacles to the delivery of diffusible substances such as oxygen and drugs.

Animals↗

PubMedDate not supplied

The RICHE Reference Architecture.

The RICHE Reference Architecture defines an open framework for health care information systems. Developed within the ESPRIT II programme, it is now the basis of several implementations in hospitals in Italy, Portugal, Ireland, France and the UK, and of follow-up initiatives such as EDITH (ESPRIT, no. 7508), NUCLEUS (AIM II, no. 2025) and REFERENCE (a French hospitals' project). This contribution describes the RICHE Reference Architecture in detail. Special concern is centred on the modulus that constitute the basic platform of RICHE, and on the methodology applied to design the interactions between them.

Artificial Intelligence↗

PubMedDate not supplied

A layered architecture for computer-based simulation supporting skills learning: an X-ray imaging paradigm.

Simulation is characterized by strong learning potential, providing the basis for a new category of systems, the simulation-based learning systems. To strengthen the learning potential of these systems, models are needed not only of the actual system being imitated, but also of the operational expertise required to carry out manipulations of the simulated system, inherently linked to learning. In this paper, an architecture is reported aimed at supporting the organization of multimodal simulation resources to induce skills learning. This architecture is based on distinct layers, allowing independent representation of learning and simulation components. Its applicability has been demonstrated by means of a paradigm, including simulation of X-ray imaging procedure, as well as authoring of learning scenarios pertaining to such procedures.

Algorithms↗

PubMedDate not supplied

A multi-agent architecture for teaching dermatology.

This work proposes the integration of computer-aided instruction systems in the curricula of medical education, and describes an intelligent tutoring system used for teaching Dermatology. The Dermatology Tutor uses a self-organized society of autonomous software agents which have different capabilities or roles. The society contains tutor, medical and information agents which participate in the tutoring process and collaborate through deliberation in order to achieve a tutoring task. The agents are built according to a BDI architecture, which implements the mental attitudes of beliefs (B), desires (D) and intentions (I). Each medical agent is a specialist in a medical field, while a tutoring agent, which implements a widely accepted dermatology teaching process, coordinates the overall operation of the system. Depending on the subject that is to be taught during any session, the tutoring agent forms teams of medical agents, which in turn use search agents to retrieve information. Although the presented multi-agent architecture is dedicated to teaching dermatology (since the tutor agent is specialized in Dermatology), it can be extended to other domains also with the incorporation of other tutor agents.

Computer Systems↗

PubMed1985

Immunohistochemical study of metastatic brain tumors with astroprotein (GFAP), a glia-specific protein. Tissue architecture and the origin of blood vessels.

Tissues from 12 metastatic tumors of the brain were studied immunohistochemically with an antiserum to a glia-specific protein, astroprotein (glial fibrillary acidic protein, GFAP). Emphasis was laid on demonstrating the tissue architecture of metastatic lesions incorporating brain-derived components (astrocytes and glial fibers). Of 12 samples, 11 manifested a number of irregular indentations at the tumor surface. These indentations, which contained astrocytic elements, extended into the tumor tissue in a tapering fashion. In seven cases, the deeper stromal portions of the tumor also contained astroprotein (GFAP)-positive elements. The presence of this glia-specific protein suggests that the stroma of the tumor tissue may in part be derived from preexisting brain tissue. This peculiar tissue architecture of the tumor supports the hypothesis that some of the blood vessels that are located in the stroma of the tumor tissue are also derived from the brain. These observations may be important in understanding the partial preservation of the blood-brain barrier in metastatic brain tumors and the mode of growth of the metastatic lesion, and in selecting the type of chemotherapy that will be most effective in controlling this central nervous system complication of systemic malignancies.

Astrocytes↗

PubMed2026

Multi-locus allelic architecture underlying natural variation in leaf rolling in japonica rice.

Leaf rolling is a key component of rice canopy architecture that affects light interception, microclimate formation, and planting density. The contribution of naturally occurring allelic variation to quantitative variation in leaf rolling within cultivated rice remains poorly understood, while extreme leaf rolling caused by loss-of-function mutations often results in detrimental pleiotropic effects. Herein, we examined how multi-locus allelic variation contributes to natural variation in leaf rolling within japonica rice. Leaf rolling was quantified based on the leaf rolling index (LRI) using a panel of 201 japonica accessions. The phenotype was transformed using the Yeo-Johnson method to reduce strong right skewness and improve the distributional properties of the data, thereby facilitating subsequent regression modeling. Haplotype analyses were performed for previously reported leaf rolling-associated genes and genome-wide association study (GWAS) lead loci, leading to the identification of five loci exhibiting substantial haplotype-dependent phenotypic variation. Phenotypically defined allelic groups represented these loci were subsequently evaluated using multiple linear regression (MLR), with the first two principal components derived from genome-wide SNP data included as covariates to account for population structure. The final MLR model identified four loci (qALR1, OsYABBY1, OsSLL2, and OsSRL10) as the independent contributors to leaf rolling variation, collectively explaining 21% of the variance in the transformed phenotype after accounting for population structure. Model diagnostics and ten-fold cross-validation supported the statistical validity of the framework and indicated stable model performance across validation folds. Analysis of multi-locus allelic combinations showed 13 distinct configurations that clustered into three phenotypically differentiated groups. This reflected the cumulative dosage of high-leaf rolling alleles. Thus, the natural variation in leaf rolling in japonica rice is governed by the additive effects of multiple moderate-impact loci. The multi-locus allelic framework established here provides a statistically sound and biologically interpretable basis for dissecting polygenic canopy traits and practical guidance for developing genetic materials aimed at optimizing rice plant architecture.

cross-validation↗

PubMed2025

Shared Genetic Architecture Between Atopic Dermatitis and Autoimmune Diseases.

Atopic dermatitis (AD) and autoimmune diseases exhibit epidemiological comorbidity, yet the shared genetic architecture remains incompletely understood. We investigated the genetic overlap between AD and three autoimmune disorders including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), and vitiligo, leveraging genome-wide association data. Despite modest evidence for global genetic correlations, we found 113 independent pleiotropic loci shared among AD and autoimmune diseases, with 11 displaying a concordant effect across all 3 pairwise comparisons. Gene-set and tissue enrichment analyses evidenced the inflammatory background of pleiotropic associations. Multi-trait colocalization analysis prioritized 22 loci, linking the tissue-specific expression of DOK2, GPR132, RERE, RERE-AS1, SUOX, TNFRSF11A, and TRAF1 pleiotropic genes with AD risk. Mendelian randomization revealed no causal effect of genetic liability to AD on autoimmune diseases. Nevertheless, genetic liability to IBD increased AD risk, while vitiligo exhibited a protective effect post outlier correction. Our findings provide mechanistic insights into the multimorbidity of atopic dermatitis (AD) and autoimmune diseases, offering additional evidence for the pleiotropic genetic architecture of AD that contributes to systemic immune dysregulation across multiple organ systems.

Humans↗

PubMed2006

Liver fibrosis and tissue architectural change measurement using fractal-rectified metrics and Hurst's exponent.

AIM: To provide the accurate alternative metrical means of monitoring the effects of new antiviral drugs on the reversal of newly formed collagen. METHODS: Digitized histological biopsy sections taken from 209 patients with chronic C virus hepatitis with different grade of fibrosis or cirrhosis, were measured by means of a new, rapid, user-friendly, fully computer-aided method based on the international system meter rectified using fractal principles. RESULTS: The following were described: geometric perimeter, area and wrinkledness of fibrosis; the collation of the Knodell, Sheuer, Ishak and METAVIR scores with fractal-rectified metric measurements; the meaning of the physical composition of fibrosis in relation to the magnitude of collagen islets; the intra- and inter-biopsy sample variability of these parameters; the"staging" of biopsy sections indicating the pathway covered by fibrosis formation towards its maximum known value; the quantitative liver tissue architectural changes with the Hurst exponent. CONCLUSION: Our model provides the first metrical evaluations of the geometric properties of fibrosis and the quantitative architectural changes of the liver tissue. The representativeness of histological sections of the whole liver is also discussed in the light of the results obtained with the Hurst coefficient.

Adult↗

PubMed2003

Changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages.

AIM: To investigate the changes of microvascular architecture, ultrastructure and permeability of rat jejunal villi at different ages. METHODS: Microvascular corrosion casting, scanning electron microscopy, transmission electron microscopy and Evans blue infiltration technique were used in this study. RESULTS: The intestinal villous plexus of adult rats consisted of arterioles, capillary network and venules. The marginal capillary extended to the base part of the villi and connected to the capillary networks of adjacent villi. In newborn rats, the villous plexus was rather simple, and capillary network was not formed. The villous plexus became cone-shaped and was closely arrayed in ablactation rats. In adult rats, the villous plexus became tongue-shaped and was enlarged both in height and width. In aged rats, the villous plexus shrank in volume and became shorter and narrower. The diametral ratio of villous arteriole to villous venule increased as animals became older. The number of endothelial holes, the thickness of basal membrane and the permeability of microvasculature were increased over the entire course of development from newborn period to aged period. CONCLUSION: The digestive and absorptive functions of the rat jejunum at different ages are highly dependent upon the state of villous microvascular architecture and permeability, and blood circulation is enhanced by collateral branches such as marginal capillary, through which blood is drained to the capillary networks of adjacent villi.

Aging↗

PubMed1991

Visual search, visual streams, and visual architectures.

Most psychological, physiological, and computational models of early vision suggest that retinal information is divided into a parallel set of feature modules. The dominant theories of visual search assume that these modules form a "blackboard" architecture: a set of independent representations that communicate only through a central processor. A review of research shows that blackboard-based theories, such as feature-integration theory, cannot easily explain the existing data. The experimental evidence is more consistent with a "network" architecture, which stresses that: (1) feature modules are directly connected to one another, (2) features and their locations are represented together, (3) feature detection and integration are not distinct processing stages, and (4) no executive control process, such as focal attention, is needed to integrate features. Attention is not a spotlight that synthesizes objects from raw features. Instead, it is better to conceptualize attention as an aperture which masks irrelevant visual information.

Attention↗

PubMed2006

Type 1 IFN deficiency in the absence of normal splenic architecture during lymphocytic choriomeningitis virus infection.

The innate immune system uses different mechanisms to respond to infectious pathogens. Experiments evaluating the requirements for a type 1 IFN (IFN-alphabeta) response to lymphocytic choriomeningitis virus (LCMV) resulted in the surprising discovery that mice deficient in B and T cell development, i.e., RAG-deficient and SCID, had profoundly reduced levels of IFN-alphabeta in serum and spleen, despite high viral replication. In addition to lacking an adaptive immune system, these strains exhibit aberrant splenic architecture, and the defect in type 1 IFN production was also observed in mice lacking normal splenic marginal zone (MZ) organization due to genetic deficiencies in B cell development or in cytokine functions required for development of the MZ, i.e., muMT, lymphotoxin-alpha, and TNFR1. Interestingly, the IFN-alphabeta reduction was not observed after murine CMV infection. Depletion of phagocytic cells from normally developed spleens by treatment with clodronate-containing liposomes demonstrated that these populations were required for the type 1 IFN response to LCMV, but not to murine CMV, and for control of viral replication. Complete repopulation of the MZ was necessary to restore normal IFN-alphabeta production. In contrast, control of LCMV replication correlated with the return of CD11c+ cells. Taken together, these results demonstrate the complexity and sophistication of the splenic MZ in sensing and responding to particular pathogens and reveal the importance of organ architecture in the production of type 1 IFN.

Animals↗

PubMed2006

Histone modifications and the chromatin scaffold for meiotic chromosome architecture.

Chromosomes are capable of remarkable structural adaptability that enables their diverse functions. Histone modifications play pivotal roles in conferring structural diversity to chromosomes by influencing the compactness of chromatin. Several multi-protein complexes bind to chromatin and affect chromosome dynamics, including cohesin, condensin, the chromosome passenger complex, and the synaptonemal complex. The roles of these complexes in promoting chromosome functions include cohesion, condensation and synapsis. It is now crucial to define the relationship between the protein complexes that affect chromosome architecture and the underlying state of the chromatin. During meiosis chromosomes undergo striking morphological changes, including alignment of homologous chromosomes, double-strand break formation and repair, and establishment of meiosis-specific chromosome structures. These dynamic chromosome arrangements are accompanied by the recruitment and expulsion of multi-protein complexes from chromatin. Meiotic chromosome dynamics ensure proper chromosome segregation and production of healthy gametes. Meiosis thus affords an excellent opportunity to determine how histone modifications impact higher order chromosome dynamics by affecting localization and function of chromosome protein complexes. A meiotic mutation in the Drosophila histone kinase, NHK-1, uncovered a critical requirement for histone modifications in chromosome architecture, underscoring the power of this approach.

Animals↗