Ray Volume Research Articles

Echocardiographic Diagnosis of Congenital Arterial Catheter Function Changes

Arterial catheter is physiological flow channel between pulmonary artery and descending aorta in fetal circulation. Most right heart blood flow through artery catheter into descending aorta during embryo period. Most term neonates are usually stopped after fetal delivery. Functional closure occurs in 48 h after birth, while 88% should be closed completely at 8 weeks after birth. There was no significant difference between PDA occlusion technique guided by transthoracic echocardiography and conventional funnel PDA closure rate, total closure rate, long term closure rate, pulmonary systolic pressure before surgery and pulmonary artery pressure difference before and after operation (P < 0.05). Conversely, under similar therapeutic effects, funnel type PDA closure guided by transthoracic echocardiography has advantages such as shorter anesthesia time, less total ray volume and contrast agent, lower hospitalization expense and fewer complications. Therefore, through transthoracic echocardiography guidance delivery of order vein approach interventional closure therapy funnel type PDA especially suitable for children, worthy of clinical application.

Shape-Based Descriptors for Efficient Structure-Based Fragment Growing.

Structure-based fragment growing is one of the key techniques in fragment-based drug design. Fragment growing is commonly practiced based on structural and biophysical data. Computational workflows are employed to predict which fragment elaborations could lead to high-affinity binders. Several such workflows exist but many are designed to be long running noninteractive systems. Shape-based descriptors have been proven to be fast and perform well at virtual-screening tasks. They could, therefore, be applied to the fragment-growing problem to enable an interactive fragment-growing workflow. In this work, we describe and analyze the use of specific shape-based directional descriptors for the task of fragment growing. The performance of these descriptors that we call ray volume matrices (RVMs) is evaluated on two data sets containing protein-ligand complexes. While the first set focuses on self-growing, the second measures practical performance in a cross-growing scenario. The runtime of screenings using RVMs as well as their robustness to three dimensional perturbations is also investigated. Overall, it can be shown that RVMs are useful to prefilter fragment candidates. For up to 84% of the 3299 generated self-growing cases and for up to 66% of the 326 generated cross-growing cases, RVMs could create poses with less than 2 Å root-mean-square deviation to the crystal structure with average query speeds of around 30,000 conformations per second. This opens the door for fast explorative screenings of fragment libraries.

Absolute Structure from Scanning Electron Microscopy

The absence of centrosymmetry in chiral and polar crystal structures is the reason for many technical relevant physical properties like optical birefringence or ferroelectricity. Other chirality related properties that are actually intensively investigated are unconventional superconductivity or unusual magnetic ordering like skyrmions in materials with B20 structure. Despite the often close crystal structure - property relation, its detection is often challenging due to superposition of domains with different absolute structure e.g. chirality. Our investigations of high quality CoSi crystals with B20 structure by both complementary methods X- ray (volume sensitive) and electron backscatter diffraction (EBSD) (surface sensitive) results the consistent assignment of the chirality and reveal fundamental differences in their sensitivity to chirality. The analysis of the surface of a CoSi crystal with domains of different chirality show the high spatial resolution of this method which opens the possibility to analyze the chirality in microstructures of technical relevant materials like thin films and catalysts.

Combined thermal, microstructural and microchemical analysis of solidification of Al25Si3Cu alloy

Purpose: This paper present thermal and microstructural and microchemical analyses were conducted on the unmodified experimental alloy Al20Si3Cu (B390.1) solidified in the High Temperature Universal Metallurgical Simulator and Analyser (HT UMSA) under atmospheric pressure (0.1 MPa) and a relatively low solidification rate (-1.2 K/s just after end of solidification), for identification of the thermal events during solidification and the phases in the as-cast structure. Design/methodology/approach: The HT UMSA platform, using a low thermal mass stainless steel cup, enabled the acquisition of high resolution thermal analysis data. Design/methodology/approach: A new approach for de-convolution of the first derivative thermal curves allowed detailed thermal and microstructural phase histories to be documented for solidification of Al-Si alloys. Recently developed SEM/EDS methodology allowed to determine composition and distribution of individual phases that are smaller than the X–ray volume. Findings: Simultaneous consideration of thermal microstructural and microchemical information allowed detailed understanding of the series of events that take place during solidification of Al casting alloy with complex chemistry. In our hypereutectic alloy we document growth of Al(1) dendrites and formation of secondary Si(2) and Al(2) phases all at temperatures higher than the binary equilibrium Al-Si eutectic temperature of 850 K. Practical implications: Even at this slow solidification rate detailed understanding of the solidification microstructure requires consideration of non-equilibrium processes during solidification. Originality/value: We propose an original set of hypotheses that consistently explain the observed non-equilibrium solidification behaviour. Proof of these hypotheses is beyond the scope of this work.

Responses of sapwood ray parenchyma and non‐structural carbohydrates of Pinus sylvestris to drought and long‐term irrigation

Summary Non‐structural carbohydrates (NSC) play a crucial role in tree resistance and resilience to drought. Stem sapwood parenchyma is among the largest storage tissue for NSC in mature trees. However, there is a limited mechanistic understanding of how NSC reserves, stem parenchyma abundance and growth rates are interrelated, and how they respond to changing water availability. We quantified NSC, ray parenchyma abundance and ring width along four successive 5‐year radial sapwood segments of the stem of 40 mature Pinus sylvestris trees from a 10‐year irrigation experiment conducted at a xeric site in Switzerland. Percentage of ray volume (PERPAR) varied from 3·75 to 8·94% among trees, but showed low intra‐individual variability. PERPAR responded positively to irrigation with a lag of several years, but was unrelated to %NSC. %NSC was lower in wider rings. However, wider rings still contained a larger NSC pool that was positively related to next year's ring growth. Our results suggest that stem ray parenchyma does not limit NSC storage capacity, but responds to long‐term environmental drivers with years of delay. The observed carbon allocation patterns indicate a prioritization of storage over growth independent of growth conditions, likely as a mechanism to ensure long‐term survival. Furthermore, NSC pool size proved to be a determinant for the inter‐annual autocorrelation in tree‐ring growth. Our study highlights the importance of long‐term multi‐parameter studies to better understand tree responses to environmental variability at different time‐scales. A lay summary is available for this article.

Importancia de la lignina en las contracciones de la madera: revisión bibliográfica

Con la información presentada en este trabajo, producto de una revisión bibliográfica, se demuestra que parte de las contracciones de la madera se puede explicar en función del contenido de lignina. La madera de angiospermas templadas, tanto de México como de Estados Unidos sufre contracciones mayores que la de angiospermas tropicales y que la de coníferas de ambos países. La rigidez tridimensional de la lignina, superior a la de los otros componentes químicos de la pared celular, conjuntamente con su escasa higroscopicidad, restringe los movimientos debidos a los cambios de humedad. Se hicieron análisis de regresión para determinar el grado de influencia de la densidad y del contenido de lignina en las contracciones radial y tangencial y se concluyó que ambas tienen importancia. La densidad resulta ser un factor de mayor importancia, pero la influencia de la lignina no es despreciable. Se destaca que es necesario efectuar estudios experimentales que determinen con toda precisión el efecto de estos factores sobre los cambios dimensionales, conjuntamente con los otros que parecen tener importancia: los extractivos y el volumen de radios.

In Planta Localization of Stilbenes within Picea abies Phloem.

Phenolic stilbene glucosides (astringin, isorhapontin, and piceid) and their aglycons commonly accumulate in the phloem of Norway spruce (Picea abies). However, current knowledge about the localization and accumulation of stilbenes within plant tissues and cells remains limited. Here, we used an innovative combination of novel microanalytical techniques to evaluate stilbenes in a frozen-hydrated condition (i.e. in planta) and a freeze-dried condition across phloem tissues. Semiquantitative time-of-flight secondary ion-mass spectrometry imaging in planta revealed that stilbenes were localized in axial parenchyma cells. Quantitative gas chromatography analysis showed the highest stilbene content in the middle of collapsed phloem with decreases toward the outer phloem. The same trend was detected for soluble sugar and water contents. The specimen water content may affect stilbene composition; the glucoside-to-aglycon ratio decreased slightly with decreases in water content. Phloem chemistry was correlated with three-dimensional structures of phloem as analyzed by microtomography. The outer phloem was characterized by a high volume of empty parenchyma, reduced ray volume, and a large number of axial parenchyma with porous vacuolar contents. Increasing porosity from the inner to the outer phloem was related to decreasing compactness of stilbenes and possible secondary oxidation or polymerization. Our results indicate that aging-dependent changes in phloem may reduce cell functioning, which affects the capacity of the phloem to store water and sugar, and may reduce the defense potential of stilbenes in the axial parenchyma. Our results highlight the power of using a combination of techniques to evaluate tissue- and cell-level mechanisms involved in plant secondary metabolite formation and metabolism.

Asymptotic method based on Maslov’s theory for the focusing of 3D elliptical lens placed in chiral medium

The high-frequency field expressions for the refracted waves from the dielectric 3D elliptical lens embedded in homogeneous and reciprocal chiral medium around the focal region are derived using an asymptotic method based on Maslov’s theory. Ray-based Geometric Optics (GO) technique was initially used to derive the expressions for the electrical field intensities for both left circular polarized and right circular polarized waves which are inherited in the chiral medium. However, GO method is not applicable at the focal points due to the shrinking of ray volume at these points which causes unreal singularities. Therefore, an asymptotic method based on Maslov’s theory is applied to derive the fields at the focal points. Moreover, the effect of chirality parameter on the behavior of focal points electric field intensities are indicated using the line plots obtained from the numerical solution of the derived equations using MATLAB software. A special case of the dielectric 3D elliptical lens placed in achiral medium is also discussed using the expressions.

Assessing Conifer Ray Parenchyma for Ecological Studies: Pitfalls and Guidelines.

Ray parenchyma is an essential tissue for tree functioning and survival. This living tissue plays a major role for storage and transport of water, nutrients, and non-structural carbohydrates (NSC), thus regulating xylem hydraulics and growth. However, despite the importance of rays for tree carbon and water relations, methodological challenges hamper knowledge about ray intra- and inter-tree variability and its ecological meaning. In this study we provide a methodological toolbox for soundly quantifying spatial and temporal variability of different ray features. Anatomical ray features were surveyed in different cutting planes (cross-sectional, tangential, and radial) using quantitative image analysis on stem-wood micro-sections sampled from 41 mature Scots pines (Pinus sylvestris). The percentage of ray surface (PERPAR), a proxy for ray volume, was compared among cutting planes and between early- and latewood to assess measurement-induced variability. Different tangential ray metrics were correlated to assess their similarities. The accuracy of cross-sectional and tangential measurements for PERPAR estimates as a function of number of samples and the measured wood surface was assessed using bootstrapping statistical technique. Tangential sections offered the best 3D insight of ray integration into the xylem and provided the most accurate estimates of PERPAR, with 10 samples of 4 mm2 showing an estimate within ±6.0% of the true mean PERPAR (relative 95% confidence interval, CI95), and 20 samples of 4 mm2 showing a CI95 of ±4.3%. Cross-sections were most efficient for establishment of time series, and facilitated comparisons with other widely used xylem anatomical features. Earlywood had significantly lower PERPAR (5.77 vs. 6.18%) and marginally fewer initiating rays than latewood. In comparison to tangential sections, PERPAR was systematically overestimated (6.50 vs. 4.92%) and required approximately twice the sample area for similar accuracy. Radial cuttings provided the least accurate PERPAR estimates. This evaluation of ray parenchyma in conifers and the presented guidelines regarding data accuracy as a function of measured wood surface and number of samples represent an important methodological reference for ray quantification, which will ultimately improve the understanding of the fundamental role of ray parenchyma tissue for the performance and survival of trees growing in stressed environments.

A Star in the Brainstem Reveals the First Step of Cortical Magnification

A fundamental question in the neurosciences is how central nervous system (CNS) space is allocated to different sensory inputs. Yet it is difficult to measure innervation density and corresponding representational areas in the CNS of most species. These measurements can be made in star-nosed moles (Condylura cristata) because the cortical representation of nasal rays is visible in flattened sections and afferents from each ray can be counted. Here we used electrophysiological recordings combined with sections of the brainstem to identify a large, visible star representation in the principal sensory nucleus (PrV). PrV was greatly expanded and bulged out of the brainstem rostrally to partially invade the trigeminal nerve. The star representation was a distinct PrV subnucleus containing 11 modules, each representing one of the nasal rays. The 11 PrV ray representations were reconstructed to obtain volumes and the largest module corresponded to ray 11, the mole's tactile fovea. These measures were compared to fiber counts and primary cortical areas from a previous investigation. PrV ray volumes were closely correlated with the number of afferents from each ray, but afferents from the behaviorally most important, 11th ray were preferentially over-represented. This over-representation at the brainstem level was much less than at the cortical level. Our results indicate that PrV provides the first step in magnifying CNS representations of important afferents, but additional magnification occurs at higher levels. The early development of the 11th, foveal appendage could provide a mechanism for the most important afferents to capture the most CNS space.

Storage versus substrate limitation to bole respiratory potential in two coniferous tree species of contrasting sapwood width

Two coniferous tree species of contrasting sapwood width (Pinus ponderosa L., ponderosa pine and Pseudotsuga menziesii Mirb., Douglas-fir) were compared to determine whether bole respiratory potential was correlated with available storage space in ray parenchyma cells and/or respiratory substrate concentration of tissues (total nitrogen content, N; and total non-structural carbohydrate content, TNC). An increment core-based, laboratory method under controlled temperature was used to measure tissue-level respiration (termed respiratory potential) from multiple positions in mature boles (>100-years-old). The most significant tissue-level differences that occurred were that N and TNC were two to six times higher for inner bark than sapwood, TNC was about two times higher in ponderosa pine than Douglas-fir and there was significant seasonal variation in TNC. Ray cell abundance was not correlated with sapwood respiratory potential, whereas N and TNC often were, implying that respiratory potential tended to be more limited by substrate than storage space. When scaled from cores to whole boles (excluding branches), potential net CO2 efflux correlated positively with live bole volume (inner bark plus sapwood), live bole ray volume, N mass, and TNC mass (adjusted R2 > or =0.4). This relationship did not differ between species for N mass, but did for live bole volume, live bole ray volume, and TNC mass. Therefore, N mass appeared to be a good predictor of bole respiratory potential. The differences in net CO2 efflux between the species were largely explained by the species' relative amounts of whole-bole storage space or substrate mass. For example, ponderosa pine's inner bark was thinner than Douglas-fir's, which had the greater concentration of ray cells and TNC compared with the sapwood. This resulted in ponderosa pine boles having 30-60% less ray volume and 10-30% less TNC mass, and caused ponderosa pine net CO2 efflux/ray volume and net CO2 efflux/TNC mass to be 20-50% higher than Douglas-fir. In addition, because inner bark respiratory potential was 2-25 times higher than that of sapwood, ponderosa pine's thinner inner bark and deeper sapwood (relative to Douglas-fir) caused its bole net CO2 efflux/live bole volume to be 20-25% lower than that of similarly-sized Douglas-fir trees.

A Meshing Scheme for Efficient Hardware Implementation of Butterfly Subdivision Using Displacement Mapping

Displacement mapping is an effective technique for encoding the high levels of detail of surface models using coarse triangle meshes and displacement maps. These maps are 2D representations containing the distances between the coarse mesh and the surface to represent. Displacement maps have been used in many applications such as ray tracing, image warping, and volume rendering. In this article, we propose modifications to our previous grouping strategy, a new subdivision strategy based on the Modified Butterfly algorithm and new heuristics for the adaptive subdivision procedure, and, finally, the corresponding modifications on our hardware proposal. A meshing scheme and an adaptive subdivision strategy based on displacement mapping reduce the bottleneck between the CPU and graphics pipeline common in high-performance graphics systems.

Wood Anatomy of Actinostrobus (Cupressaceae)

The wood anatomy of the Western Australian species Actinostrobus arenarius (Cupressaceae) is described for the first time and its features are compared with those of the two other species in the genus: A. acuminatus and A. pyramidalis. Mature heartwood in A. arenarius is light-brown in colour and has an air-dry density of 0.56 g/cm3. Average tracheid length is 4.3 mm. A very prominent warty layer, with individual warts commonly greater than one micron in height and large enough to be visible to light microscopy, lines the inner walls of tracheids. Callitroid thickening is commonly present in narrow (latewood) tracheids, but is absent from wide ones (earlywood). Axial parenchyma cells with dark-red resinous inc1usions are tangentially zonate in earlywood. Bordered pitting in earlywood and latewood is uniseriate. Pit borders are circular and there is a raised torus. Average ray height is low. Cross-field pitting is cupressoid and the number of pits per cross field ranges from two to five, with a mean of 3.1. Average ray heights, ray frequencies, ray volumes, and numbers of pits present in cross fields are higher in A. arenarius than in A. pyramidalis, thus supporting the classification of A. arenarius as aseparate species within Actinostrobus. Veins of distorted xylem cells, similar in appearance to 'frost rings' occur sporadically in the sterns of a11 three species. If such rings are confined to Actinostrobus, then the combination of a very prominent warty layer, and the common occurrence of frost rings could provide a means of separating Actinostrobus from Callitris. Validation of this scheme requires further research to determine if such rings commonly occur in Callitris.

512 poster Low dose, fast, X ray volume imaging for intra-cranial and head & neck radiotherapy

512 poster Low dose, fast, X ray volume imaging for intra-cranial and head & neck radiotherapy

Pseudo-gamma ray volume from extended elastic impedance inversion for gas exploration

The Unayzah Formation has been an exploration target in Saudi Arabia for more than a decade, with oil and gas production from the unit now well established. However, exploration in the Unayzah in central Saudi Arabia remains technically challenging. This is due in large part to its complex interplay of continental clastic depositional environments that include braided stream, wadi fill, playa-lake, interfluve, alluvial fan, and eolian dune systems.

Is ray volume a possible factor influencing ring shake occurrence in chestnut wood?

Radially oriented ray tissue is important for regulating radial strength of wood. The present study was undertaken in order to assess whether radial rays influence ring shake occurrence in chestnut wood (Castanea sativa Mill.), a species very prone to ring shake. Ray volume fraction was measured on tangential samples from two sets of wood discs, either with or without ring shake, collected from three coppice stands in the southern part of the Swiss Alps. Our data indicate that ring shaken trees tend to exhibit higher ray volume than unshaken ones. This rather unexpected finding could be partly explained if biomechanical processes that control and determine the inner architecture of the tree are considered.

DISTRIBUTION AND VITALITY OF XYLEM RAYS IN RELATION TO TREE LEAF AREA IN DOUGLAS-FIR

The factors that determine sapwood width and volume in a tree are not known. This study asked whether sapwood width is related to a need for stem storage sites. Experiments were conducted on 12 34-year-old Douglas-fir [(Pseudotsuga menziesii (Mirb.) Franco] trees with a 6-7 fold range of leaf areas and leaf area/sapwood volumes. Because of declining ray frequency but constant average ray area, ray volume declined for the first 6-10 growth rings, then remained constant, and did not vary with height (breast height vs. 10 nodes from the top). Fewer of the ray parenchyma cells had nuclei in inner than outer sapwood. Inner sapwood had ray parenchyma with smaller rounder nuclei than did outer sapwood, and there was no effect of height. There was a positive relationship between leaf area and the relative volume of ray in outer sapwood at breast height (r = 0.646, p = 0.02), supporting the hypothesis that Douglas-fir trees with larger leaf areas have higher ray volume than do trees with smaller leaf areas. However, correlations of leaf area I sapwood volume with leaf area at either height were not significant, nor were correlations of either leaf area or leaf area/sapwood volume with measures of ray vitality (nuclear frequency in outer sapwood, or the ratio of nuclear frequency in the middle I outer sapwood or in inner I outer sapwood). These latter correlations give no evidence that Douglas-fir trees determine their sapwood volume based on a need for quantity of vital xylem rays.

In vitro estimation of foetal liver volume using ultrasound, x-ray computed tomography and magnetic resonance imaging

Sixteen formalin-fixed foetal livers were scanned in vitro using a new system for estimating volume from a sequence of multiplanar 2D ultrasound images. Three different scan techniques were used (radial, parallel and slanted) and four volume estimation algorithms (ellipsoid, planimetry, tetrahedral and ray tracing). Actual liver volumes were measured by water displacement. Twelve of the sixteen livers also received x-ray computed tomography (CT) and magnetic resonance (MR) scans and the volumes were calculated using voxel counting and planimetry. The percentage accuracy (mean ) was , and for ultrasound (radial scans, ray volumes), MR and CT (voxel counting) respectively. The new system may be useful for accurately estimating foetal liver volume in utero. Keywords: volume, computed tomography, magnetic resonance, three-dimensional ultrasound

Investigation of standard sources for determination of natural radioactivity

Comparative measurements are presented on standard ray volume sources used for the assay of natural radioactivity. The sources compared were made from Canadian and Russian uranium and thorium reference ores as well as from standardized solutions of 226Ra and 228Th. In addition, for 232Th chemically pure thorium compounds were used. Measurements were carried out with three types of detector, hyperpure Ge, Ge(Li) and NaI(Tl). The results of many comparative measurements in two different laboratories are discussed.

Hard X-Ray Emission from Extragalactic IRAS 12 Micron Sources: Constraints on the Unified Active Galactic Nucleus Model and the Synthesis of the X-Ray Background

We analyze the $2-10$~keV X-ray emission of complete samples of AGN and galaxies selected at 12$\mu$m and recently compiled by Rush, Malkan \& Spinoglio (1993). As a necessary complement we also study the IR emissivity of the largest sample of hard X--ray selected AGN (Grossan 1992). Our purposes are to probe the unified scheme of active nuclei and to evaluate the local X--ray volume emissivity of low luminosity and `hidden' AGN. We confirm that X-ray emission is basically restricted to AGN, Seyfert 1's being much more powerful emitters than Seyfert 2's. We find no signal of X-ray emission for the remaining galaxies selected at $12\mu$m, not even for those having a flat far-infrared spectrum, which would be prime candidates to host hidden AGN. Our result on the local volume emissivity of the Seyfert 1's is fully consistent with those derived from studies of the hard X--ray luminosity function. However the 95$\%$ upper limits to the local emissivity we derive for the Seyfert 2 class and for the most likely `hidden' AGN candidates, severely constrain (and in some cases exclude) models of the X--ray background based on the unified Seyfert scheme. We also find that less than $\sim20$\% of Seyfert 1-like AGN and less than $\sim 50$\% of Seyfert 2-like AGN can be `hidden' in the non-Seyfert galaxy samples assuming that the X-ray to 12$\mu$m flux ratios measured in the 12$\mu$m selected samples can be considered typical for these classes of objects. In this case, the number ratio of Seyfert 2 to Seyfert 1 galaxies ranges from 1 to 2.