Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SPACE”

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.

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

At least 55 records · Page 3Linked to original sources
PubMed1991

[The posterior interparietoperitoneal spaces or retroperitoneal spaces. 1: Normal topographic anatomy].

The posterior spaces between the wall and peritoneum or extraperitoneal spaces are located between the visceral retrocolic and retro-duodenopancreatic fascias anteriorly and the parietalis fascia posteriorly. They were studied using an anatomic and computed tomographic comparison. The propria fascia (lateroconal fascia) divided into the anterior and posterior layers of the perirenal fascia. The fascias delimitate two anterior and posterior pararenal spaces around the kidney compartment and two anterior and posterior perirenal spaces in the compartment itself. These spaces extended above and below the renal compartment from the diaphragm to the pelvis. These large spaces composed of fat and organs can assume the guided migration of pathologic processes or their spread according to the importance of the fascias barriers. They below to the genito-urinary region. The extraperitoneal spaces are related anteriorly to the retroperitoneal alimentary organs: duodenum, pancreas, ascending and descending colon depending of the alimentary region. They are related posteriorly with the abdominal wall and its own fat. The individuality and the interdependance of these three territories (alimentary, genito-urinary and abdominal wall) and their consequences for pathologic CT scan imaging will be discussed in the second part of this paper.

Humans↗
PubMed2002

Plan space: representation of treatment plans in multidimensional space.

PURPOSE: Treatment planning balances the need to provide adequate radiation coverage of the target with the need to reduce against the risk of overdosing normal tissues. An acceptable plan fulfills minimum dose-volume criteria for irradiation of tumor and normal tissues. However, multiple plans can satisfy these minimum criteria, and some plans provide for better protection of normal tissue than others. Here, we present a method to help the planner compare plans and decide whether a particular plan is the "best" plan on the basis of a set of certain dose-volume conditions. METHODS AND MATERIALS: Treatment plans are represented as points in multidimensional space. One dimension is assigned to the target and one to normal tissues of each anatomic structure under consideration. Minimum target dose is used as the target axis coordinate and the percentage volume of each normal structure receiving more than a specified dose as each normal-tissue coordinate. Images of plan space are developed for model phantom anatomy as well as for two clinical cases in the thorax and abdomen. RESULTS: When a sufficient number of plans have been plotted, a feasibility boundary becomes evident. This hypersurface in plan space represents the limit of the given treatment technique. By using a plan on this boundary, the benefits of a given treatment modality are maximized, providing assurance that the selected plan is the "best" plan. The beam angles and relative weights of a plan can be changed to alter its position in plan space, allowing improvements in an existing plan. Frequently, plans with normal-tissue dose distributions superior to the minimum acceptable criteria can be selected. The benefits of using plan-space images have been demonstrated at sites in the thorax and abdomen. CONCLUSION: Instead of defining dose-volume criteria at the outset, it is possible to select the best achievable plans by first evaluating the space of possible plans for a particular patient's unique anatomy and then choosing the plan with the optimum dose-volume characteristics. No attempt is made to arrive at a single plan score so that explicit judgments about the relative worth of individual structures are avoided. Visualization of plan-space images allows physicians to make choices based on their assessment of the relative significance of irradiation of each normal structure.

Humans↗
PubMed2001

Molecular similarity based estimation of properties: a comparison of structure spaces and property spaces.

Molecular similarity methods have emerged as powerful tools in analog selection, chemical classification based on toxic modes of action, and property estimation. The basic assumption of structure-activity relationships (SAR) is that similar structures usually have similar properties. Therefore, similarity methods can be used for the selection of analogs and estimation of properties of chemicals from their structural analogs in property spaces. Each similarity method is user defined. Its efficacy depends on the set of descriptors used to define the intermolecular similarity of chemicals as well as on the mathematical function used to quantify similarity. Also, similarity methods can be based on experimental data or computed molecular descriptors. We have carried out a comparative study of similarity spaces derived from experimental data vis-a-vis computed structural parameters for two sets of chemicals: (a) a diverse set of 76 chemicals derived from the TSCA Inventory and (b) the 166 structurally distinct constituents of JP-8 identified by GC/MS. Property spaces for these two sets of chemicals were created using experimental and calculated physicochemical properties. Atom pairs (APs) and topological indices calculated by POLLY v2.3 were used to create theoretical structure spaces. These spaces were used for the KNN-based estimation of properties with K=1--10, 15, 20, 25. The results will be presented with a comparative analysis of the effectiveness of property spaces and structure spaces in analog selection and property estimation.

Models, Theoretical↗
PubMed1984

Computed tomography of the carotid space and related cervical spaces. Part I: Anatomy.

The carotid space, parapharyngeal space, and paraspinal space are described. The carotid space is shown on computed tomography (CT) to be posterior to the parapharyngeal space and separated from it by the styloid apparatus. The paraspinal space is posterior to the carotid space and separated from it by the longus and anterior scalene muscles.

Humans↗
PubMed1987

Effects of population size, floor space, and feeder space upon productive performance, external appearance, and plasma corticosterone concentration of laying hens.

Effects were studied of population size, floor area, and feeder space per hen on variables associated with egg production and corticosterone level. A total of 408 White Leghorn-type laying hens was used in this study. Three treatments were observed: 5 hens per cage with 8.6 cm feeder space per hen, 5 hens per cage with 12 cm feeder space per hen, and 7 hens per cage with 8.6 cm feeder space per hen. Both 5-hen treatments had 420 cm2 of cage area per hen, while the 7-hen treatment had 300 cm2. Increased population size, reduced feeder space, and reduced floor area per hen resulted in a significant (P less than .01) decline in percent egg production. Restriction of feeder space was correlated with reduced feed consumption and mortality but not feed conversion, weight gain, and egg size. As cage space allowance increased, feed consumption and weight gain were higher, whereas mortality, feed conversion, and egg weight were lower. No significant (P greater than .05) differences in shell thickness, specific gravity, Haugh unit, throat skin ateromata, claw length, and corticosterone level were observed. Plumage condition and foot health were improved only when floor area allowances increased.

Animals↗
PubMed1997

The Frog in Space (FRIS) experiment onboard Space Station Mir: final report and follow-on studies.

The "Frog in Space" (FRIS) experiment marked a major step for Japanese space life science, on the occasion of the first space flight of a Japanese cosmonaut. At the core of FRIS were six Japanese tree frogs, Hyla japonica, flown on Space Station Mir for 8 days in 1990. The behavior of these frogs was observed and recorded under microgravity. The frogs took up a "parachuting" posture when drifting in a free volume on Mir. When perched on surfaces, they typically sat with their heads bent backward. Such a peculiar posture, after long exposure to microgravity, is discussed in light of motion sickness in amphibians. Histological examinations and other studies were made on the specimens upon recovery. Some organs, such as the liver and the vertebra, showed changes as a result of space flight; others were unaffected. Studies that followed FRIS have been conducted to prepare for a second FRIS on the International Space Station. Interspecific diversity in the behavioral reactions of anurans to changes in acceleration is the major focus of these investigations. The ultimate goal of this research is to better understand how organisms have adapted to gravity through their evolution on earth.

Acceleration↗
PubMed2004

Lamina cribrosa thickness and spatial relationships between intraocular space and cerebrospinal fluid space in highly myopic eyes.

PURPOSE: To evaluate the spatial relationships of the intraocular space, the cerebrospinal fluid space, and the lamina cribrosa in highly myopic eyes. METHODS: The study included 36 human globes with an axial length of more than 26.5 mm that showed marked glaucomatous optic nerve damage (n = 29; highly myopic glaucomatous group) or in which the optic nerve was affected by neither glaucoma nor any other disease (n = 7; highly myopic normal group). Two non-highly myopic control groups included 53 globes enucleated because of malignant choroidal melanoma (n = 42; non-highly myopic normal group) or because of painful absolute secondary angle-closure glaucoma (n = 11; non-highly myopic glaucomatous group). Anterior-posterior histologic sections through the pupil and the optic disc were morphometrically evaluated. RESULTS: In both highly myopic groups compared with both non-highly myopic groups and in the highly myopic glaucomatous group compared with the highly myopic normal group, the lamina cribrosa was significantly (P < 0.001) thinner. Correspondingly, the distance between the intraocular space and the cerebrospinal fluid space was significantly (P < 0.05) shorter in the highly myopic normal group than in the non-highly myopic normal group and in the highly myopic glaucomatous group than in the highly myopic normal group. CONCLUSIONS: In highly myopic eyes, the lamina cribrosa is significantly thinner than in non-highly myopic eyes, which decreases the distance between the intraocular space and the cerebrospinal fluid space and steepens the translaminar pressure gradient at a given intraocular pressure, which may explain the increased susceptibility to glaucoma in highly myopic eyes. As in non-highly myopic eyes, thinning of the lamina cribrosa gets more pronounced in highly myopic eyes if glaucoma is also present.

Body Weights and Measures↗
PubMed1996

Rat parathyroid gland, with special reference to its blood vascular bed, pericapillary space and intercellular space.

The blood vascular bed, perivascular space and intercellular space of the rat parathyroid gland were studied using scanning electron microscopy of vascular casts, freeze-cracked tissue samples, and NaOH-digested tissue blocks. The findings were supplemented by transmission light and electron microscopy of iron colloid-treated or enzyme-digested tissue sections. The rat parathyroid gland contained a rich network of capillaries. These capillaries were surrounded by marked pericapillary spaces which were demarcated by basal lamina of both capillaries and parenchymal cells. The pericapillary spaces contained numerous collagen fibrils, and issued many crista-like projections which ran deep into the sheets of parenchymal cells. The intercellular spaces of parenchymal cells contained neither basal lamina nor collagen fibrils. The surfaces of the parenchymal cells showed strong negative charging, and maintained the intercellular spaces. The luminal surfaces of the capillary endothelium also showed strong negative charging, and maintained the capillary lumen.

Animals↗
PubMed2001

[Proposal from space radiation biologists. Importance of Centrifuge Facility in the study of biological effect by space radiation].

In microgravity, astronauts were constantly exposed to space radiation containing various kinds of radiation with a low-dose rate during long-term stays in space. It is very difficult to define the relative biological effectiveness (RBE) of space radiation under microgravity. In order to understand correct the RBE of space radiation, therefore, utilization of Centrifuge Facility is desired as a control experiment at orbit for removing other factors such as microgravity except space radiation. Here, we summarized the importance of Centrifuge Facility in the study of biological effect of space radiation.

Aerospace Medicine↗
PubMed1999

Calcium utilization by quail embryos during activities preceding space flight and during embryogenesis in microgravity aboard the orbital space station MIR.

A series of studies were conducted to determine the effect of activities preceding spaceflight and during space-flight on calcium utilization during quail embryonic development. In the pre-space trials, fertile quail eggs were subjected to pre-flight dynamics including forces of centrifugation, vibration, or a combination of vibration and centrifugation prior to incubation for 6 or 16 days. Quail eggs were also tested for survivability in a refrigerator stowage kit for eggs (RSKE) which was subsequently used to transport the eggs to space. Eggs in the RSKE were subjected to shuttle launch dynamics including G force and random vibration profiles. The space-flight trial involved 48 quail eggs launched on space shuttle Flight STS-76 which were subsequently incubated in a Slovakian incubator onboard space station, MIR. Two ground control trials, each with 48 eggs with and without exposure to shuttle launch dynamics were initiated 5 days post-launch. Eggshells from all study trials were retrieved and analyzed for calcium content. Results showed that neither pre-flight activities nor shuttle launch dynamics had an effect on calcium utilization by developing embryos. However, calcium utilization by developing embryos incubated in microgravity was impaired by 12.6% when compared to embryos incubated on earth under laboratory control environment. This impairment was believed to be due to unidentified factors of the microgravity environment.

Animals↗
PubMed2001

RBE of radiations in space and the implications for space travel.

Space travellers are irradiated with cosmic rays to a dose rate considerably higher than that received on earth. In order to make sensible judgements about space exploration, the risks to health of such radiation need to be assessed. Part of the assessment of risk is to allow for the enhanced biological effectiveness of high LET radiations with respect to others. In space the high LET radiations of concern are high energy neutrons and charged particles. At the doses and dose rates encountered in space, the important risk is the induction of cancer in the astronauts. For this biological end-point there is no direct human evidence for the relative effectiveness of these radiations. There are some data for neutrons for cancer and life-shortening in laboratory animals but these are for fission spectra neutrons, which are of lower energy than those encountered in space. There is a small amount of data for protons and high energy heavier charged particles. The remaining evidence comes from cellular experiments observing chromosome aberrations and gene mutations. From this sparse information, pragmatic choices need to be made for application to protection in space. The data are reviewed and the bases for the pragmatic choices discussed.

Animals↗
PubMed2005

Parallel magnetic resonance imaging with adaptive radius in k-space (PARS): constrained image reconstruction using k-space locality in radiofrequency coil encoded data.

A parallel image reconstruction algorithm is presented that exploits the k-space locality in radiofrequency (RF) coil encoded data. In RF coil encoding, information relevant to reconstructing an omitted datum rapidly diminishes as a function of k-space separation between the omitted datum and the acquired signal data. The proposed method, parallel magnetic resonance imaging with adaptive radius in k-space (PARS), harnesses this physical property of RF coil encoding via a sliding-kernel approach. Unlike generalized parallel imaging approaches that might typically involve inverting a prohibitively large matrix for arbitrary sampling trajectories, the PARS sliding-kernel approach creates manageable and distributable independent matrices to be inverted, achieving both computational efficiency and numerical stability. An empirical method designed to measure total error power is described, and the total error power of PARS reconstructions is studied over a range of k-space radii and accelerations, revealing "minimal-error" conditions at comparatively modest k-space radii. PARS reconstructions of undersampled in vivo Cartesian and non-Cartesian data sets are shown and are compared selectively with traditional SENSE reconstructions. Various characteristics of the PARS k-space locality constraint (such as the tradeoff between signal-to-noise ratio and artifact power and the relationship with iterative parallel conjugate gradient approaches or nonparallel gridding approaches) are discussed.

Algorithms↗
PubMed2004

Exchange of histidine spacing between Sp1 and GLI zinc fingers: distinct effect of histidine spacing-linker region on DNA binding.

In the DNA recognition mode of C(2)H(2)-type zinc fingers, the finger-finger connection region, consisting of the histidine spacing (HX(3-5)H) and linker, would be important for determining the orientation of the zinc finger domains. To clarify the influence of spacing between two ligand histidines in the DNA binding, we exchanged the histidine spacing between Sp1 and GLI zinc fingers, which have an HX(3)H-TGEKK linker (typical) and an HX(4)H-SNEKP linker (atypical), respectively. A significant decrease in the DNA binding affinity and specificity is found in Sp1-type peptides, whereas GLI-type peptides show a mild reduction. To evaluate the effect of the linker characteristics, we further designed Sp1-type mutants with an SNEKP linker. As a result, the significant effect of the histidine spacing in Sp1-type peptides was reduced. These results demonstrate that (1) the histidine spacing significantly affects the DNA binding of zinc finger proteins and (2) the histidine spacing and the following linker regions are one effective target for regulating the DNA recognition mode of zinc finger proteins.

Amino Acid Sequence↗
PubMed2001

Superomedial lid crease approach to the medial intraconal space: a new technique for access to the optic nerve and central space.

PURPOSE: To present clinical and cadaver studies of a new approach to the medial intraconal space. METHODS: We retrospectively review our clinical results by using a new technique to gain access to the medial intraconal space through a superomedial lid crease incision. We also use cadaver dissection studies to compare this new approach with the medial transconjunctival approach, the lateral orbitotomy without bone-flap, and the lateral orbitotomy with bone-flap. RESULTS: Access to the medial intraconal orbital space through the superomedial lid crease incision allowed optic nerve sheath fenestration or biopsy in 18 eyes with few postoperative complications. One case of tonic pupil, one case of transient vertical diplopia, and two cases of transient medial ptosis were seen. Five cavernous hemangiomas were removed from the intraconal space with this approach, with one case of transient vertical diplopia and one case of transient medial ptosis. The cadaver studies showed that when the superomedial lid crease approach is used, the tangent angle with the optic nerve and the incision-to-nerve distance measurements compare favorably with the medial transconjunctival and the lateral orbital approaches. CONCLUSIONS: The superomedial lid crease approach to the medial intraconal space has a number of advantages over the medial transconjunctival and lateral orbital approaches, including ease of dissection, incision-to-nerve distance, and angle of approach to the optic nerve. This technique allows for optic nerve sheath fenestration or tumor removal from the central space with few complications.

Adolescent↗
PubMed1987

Separation of the masticator space from the parapharyngeal space.

The separation of the masticator and parapharyngeal spaces is somewhat ambiguous. Anatomic specimens were dissected to define better the fascial layer representing the medial wall of the masticator space. A fascial layer was found extending from the medial pterygoid muscle to the skull base separating the masticator from the parapharyngeal space. The third branch of the trigeminal nerve was lateral to this fascial layer and thus passed through the masticator space. Clinical cases were reviewed. Tumors could be confidently assigned to the masticator, prestyloid, or poststyloid parapharyngeal spaces. Benign salivary gland tumors were found in the prestyloid parapharyngeal space only.

Face↗
PubMed1991

Public school teachers in the U.S. evaluate the educational impact of student space experiments launched by expendable vehicles, aboard Skylab, and aboard Space Shuttle.

Space education is a discipline that has evolved at an unprecedented rate over the past 25 years. Although program proceedings, research literature, and historical documentation have captured fragmented pieces of information about student space experiments, the field lacks a valid comprehensive study that measures the educational impact of sounding rockets, Skylab, Ariane, AMSAT, and Space Shuttle. The lack of this information is a problem for space educators worldwide which led to a national study with classroom teachers. Student flown experiments continue to offer a unique experiential approach to teach students thinking and reasoning skills that are imperative in the current international competitive environment in which they live and will work. Understanding the history as well as the current status and educational spin-offs of these experimental programs strengthens the teaching capacity of educators throughout the world to develop problem solving skills and various higher mental processes in the schools. These skills and processes enable students to use their knowledge more effectively and efficiently long after they leave the classroom. This paper focuses on student space experiments as a means of motivating students to meet this educational goal successfully.

Cognition↗