Tadpole Shape Research Articles

SU‐E‐T‐461: Using Foldable Gold Anchor Markers for IGRT Fiducial Tracking

Purpose: Tracking gold markers is a direct method of tumor localization in IGRT. Foldable gold anchor markers can be inserted using narrow needle (22 or 25 gauge) with less morbidity. We explored the feasibility of using anchor makers for IGRT.Methods: The anchor markers are either 10 mm or 20 mm long gold wires. Small notches every 2.0 mm in the wire allow the wire to fold into a dense ball shape when injected, whose angled edge makes fiducial migration less possible. Alternatively, different combination of advancing stylet and retracting needle can place the gold wire into the tissue as either a linear or a tadpole shaped marker. In our phantom study, three 20‐mm wires were placed into a bolus and each folded into ball, linear and tadpole shapes. The bolus was placed on top solid water phantom and scanned. The visualization of these markers on different imaging devices (OBI, cone beam CT, portal image, Acculoc and Cyberknife imaging tracking system) are evaluated. Clinical experience includes lung, liver, prostate and pancreases. The tracking ability of the imaging system on the anchor is evaluated.Results: All markers are clearly visible with kilo‐voltage imaging devices. In our Cyberknife test, anchor markers were visible under default X‐ray parameters. The precision of the lock‐on is within 1 mm, except for the linear marker. When employs mega voltage (MV) portal images with Acculoc system, the ball shaped anchor marker is the most visible in identification and linear one is the least. In clinic, no toxicity was observed resulting from the fiducial placement Conclusions: The gold anchor markers appear comparable with traditional solid gold markers.

Effects of copper, zinc and dragonfly kairomone on growth rate and induced morphology of Bufo arabicus tadpoles

It is well documented that many amphibian species can detect chemical signals from predatory invertebrates and subsequently develop alternate phenotypes that are protective against predation. The effects of metallic pollutants on the development of predator-induced morphology have not previously been reported. Tadpoles of the Arabian toad Bufo arabicus were exposed for 20 days to copper (0, 10 or 100 μg/L), zinc (0, 10 or 100 μg/L) and kairomones of larval dragonflies ( Crocothemis erythrea 1 dragonfly/12 L) in a fully crossed design. The effects of these treatments of growth and body shape were measured. Measured copper concentrations after 24 h were 4.25 μg/L±1.30 (10 μg/L nominal) and 34.9 μg/L±2.15 (100 μg/L nominal). Measured zinc concentrations were 3.04 μg/L±0.1 (10 μg/L nominal) and 26.3 μg/L±12.3 (100 μg/L nominal). Tadpoles exposed to 34.9 μg/L copper were significantly lighter and had a shorter body length than other groups. There was no direct effect of zinc on growth or tadpole shape. Tadpoles exposed to dragonfly kairomones were heavier, wider and had deeper bodies when viewed laterally and had longer tails but overall length was not affected. At 4.25 μg/L copper differences between the control and predator-exposed phenotypes increased but at 34.9 μg/L the phenotypes converged, indicating that copper may inhibit the induced response.

Acoustic Droplet Vaporization for the Enhancement of Ultrasound Thermal Therapy.

Acoustic droplet vaporization (ADV) is an ultrasound method for converting biocompatible microdroplets into microbubbles. The objective is to demonstrate that ADV bubbles can enhance high intensity focused ultrasound (HIFU) therapy by controlling and increasing energy absorption at the focus. Thermal phantoms were made with or without droplets. Compound lesions were formed in the phantoms by 5-second exposures with 5-second delays. Center to center spacing of individual lesions was 5.5 mm in either a linear pattern or a spiral pattern. Prior to the HIFU, 10 cycle tone bursts with 0.25% duty cycle were used to vaporize the droplets, forming an "acoustic trench" within 30 seconds. The transducer was then focused in the middle of the back bubble wall to form thermal lesions in the trench. All lesions were imaged optically and with 2T MRI. With the use of ADV and the acoustic trench, a uniform thermal ablation volume of 15 cm(3) was achieved in 4 minutes; without ADV only less than 15% of this volume was filled. The commonly seen tadpole shape characteristic of bubble-enhanced HIFU lesions was not evident with the acoustic trench. In conclusion, ADV shows promise for the spatial control and dramatic acceleration of thermal lesion production by HIFU.

TADPOLE GALAXIES IN THE HUBBLE ULTRA DEEP FIELD

Tadpole galaxies have a head-tail shape with a large clump of star formation at the head and a diffuse tail or streak of stars off to one side. We measured the head and tail masses, ages, surface brightnesses, and sizes for 66 tadpoles in the Hubble Ultra Deep Field (UDF), and we looked at the distribution of neighbor densities and tadpole orientations with respect to neighbors. The heads have masses of 10^7-10^8 Msun and photometric ages of ~0.1 Gyr for z~2. The tails have slightly larger masses than the heads, and comparable or slightly older ages. The most obvious interpretation of tadpoles as young merger remnants is difficult to verify. They have no enhanced proximity to other resolved galaxies as a class, and the heads, typically less than 0.2 kpc in diameter, usually have no obvious double-core structure. Another possibility is ram pressure interaction between a gas-rich galaxy and a diffuse cosmological flow. Ram pressure can trigger star formation on one side of a galaxy disk, giving the tadpole shape when viewed edge-on. Ram pressure can also strip away gas from a galaxy and put it into a tail, which then forms new stars and gravitationally drags along old stars with it. Such an effect might have been observed already in the Virgo cluster. Another possibility is that tadpoles are edge-on disks with large, off-center clumps. Analogous lop-sided star formation in UDF clump clusters are shown.

Impulsively Generated Wave Trains in a Solar Coronal Loop

Impulsively generated fast magnetoacoustic wave trains in a solar coronal loop are numerically studied. The problem is considered as 2-D in space, and for the description, the full set of magnetohydrodynamic (MHD) equations is used. The numerical solution of the MHD equations is performed by means of the Lax–Wendroff algorithm on a uniformly structured mesh. The wavelet analysis of the obtained wave trains shows out the typical tadpole shapes, i.e., a narrow tail followed by a broadband head. In this paper, we discuss the propagation speed and periods of the wave trains as well as the shapes of the tadpoles in dependence on the plasma beta parameter. These studies are very important in connection with the observations because the tadpole signatures, firstly discovered during the solar eclipse in 1999 by the SECIS instrument, have been recently recognized also in decimetric type IV radio events by the Ondřejov radiospectrograph.

Vulvar syringomas presenting with a polypoid mass or pruritus: Report of two cases

Syringoma is a benign eccrine sweat gland tumor and it presents more frequently in women at puberty as multiple, tiny, firm, skin-colored papules at the upper cheek and eyelid. We report here on two cases with an unusual location of syringomas on the vulva. The first case presented with multiple erythematous papules on the labia majora in a 30-year-old woman who presented with pruritus, which waxed and waned according to her menstrual cycle. The second case occurred as a polypoid mass on the prepuce in a 46-year-old woman who had been suffering from groin pruritus. Microscopically, both cases showed aggregates of ducts lined by two-layers of epithelial cells embedded in a dense fibrous stroma. Some of these ducts showed comma-like tails that gave them a tadpole shape. Albeit uncommon in vulvar region, syringoma should be included in the differential diagnosis of a pruritic vulvar lesion, and even a polypoid mass.

A “FIREWORK” OF H2KNOTS IN THE PLANETARY NEBULA NGC 7293 (THE HELIX NEBULA)

We present a deep and wide field-of-view (4'x 7') image of the planetary nebula (PN) NGC 7293 (the Helix Nebula) in the 2.12 micron H2 v=1-0 S(1) line. The excellent seeing (0.4'') at the Subaru Telescope, allows the details of cometary knots to be examined. The knots are found at distances of 2.2'-6.4' from the central star (CS). At the inner edge and in the inner ring (up to 4.5' fromthe CS), the knot often show a `tadpole' shape, an elliptical head with a bright crescent inside and a long tail opposite to the CS. In detail, there are variations in the tadpole shapes, such as narrowing tails, widening tails, meandering tails, or multi-peaks within a tail. In the outer ring (4.5'-6.4' from the CS), the shapes are more fractured, and the tails do not collimate into a single direction. The transition in knot morphology from the inner edge to the outer ring is clearly seen. The number density of knots governs the H2 surface brightness in the inner ring: H2 exists only within the knots. Possible mechanisms which contribute to the shaping of the knots are discussed, including photo-ionization and streaming motions. A plausible interpretation of our images is that inner knots are being overrun by a faster wind, but that this has not (yet) reached the outer knots. Based on H2 formation and destruction rates, H2 gas can survive in knots from formation during the late asymptotic giant branch (AGB) phase throughout the PN phase. These observations provide new constraints on the formation and evolution of knots, and on the physics of molecular gas embedded within ionized gas.

Development of the appendicularianOikopleura dioica: Culture, genome, and cell lineages

Appendicularians are planktonic tunicates (urochordates), and retain a swimming tadpole shape throughout their life. Together with ascidians, they are the closest relatives of the vertebrates. Oikopleura dioica is characterized by its simplified life habit and anatomical organization. It has a tiny genome, the smallest ever found in a chordate. Its life cycle is extremely short - about 5 days - and it can be maintained in the laboratory over many generations. Embryos and adults are transparent and consist of a small number of cells. The anatomy of juveniles and adults has been described in detail. Cleavage pattern, cell lineages, and morphogenetic movements during embryogenesis have also been comprehensively documented. A draft genome sequence is now available. These features make this organism a suitable experimental model animal in which genetic manipulations would be feasible, as in Drosophila and Caenorhabditis elegans. In this review, I summarize a hundred years' knowledge on the development throughout the life cycle of this organism. Oikopleura is an attractive organism for developmental and evolutionary studies of chordates. It offers considerable promise for future genetic approaches.

Cleavage pattern, gastrulation, and neurulation in the appendicularian, Oikopleura dioica

The appendicularian, Oikopleura dioica is a chordate. Its life cycle is extremely short--approximately 5 days--and its tadpole shape with a beating tail is retained throughout entire life. The tadpole hatches after 3 h of development at 20 degrees C. Here, we describe the cleavage pattern and morphogenetic cell movements during gastrulation and neurulation. Cleavage showed an invariant pattern. It is basically bilateral but also shows various minor left-right asymmetries starting from the four-cell stage. We observed two rounds of unequal cleavage of the posterior-vegetal B-line cells at the posterior pole. The nature of the unequal cleavages is reminiscent of those in ascidian embryos and suggests the presence of a centrosome-attracting body, a special subcellular structure at the posterior pole. The representation of the cell division pattern in this report will aid the identification of each cell, a prerequisite for clarifying the gene expression patterns in early embryos. Gastrulation started as early as the 32-cell stage and progressed in three phases. By the end of the second phase at the 64-cell stage, every vegetal cell had ingressed into the embryo, and animal cells had covered the entire embryo by epiboly. There was no archenteron formation. In the anterior region, eight A-line cells were aligned as a 2x4 array along the anterior-posterior axis and become internalized during the 64-cell stage. This process was considered to correspond to neurulation. The simple and accelerated development of Oikopleura, nevertheless giving rise to a conserved chordate body plan, is advantageous for studying developmental mechanisms using molecular and genetic approaches and makes this animal the simplest model organism in the phylum Chordata.

Numerical Simulations of Impulsively Generated Magnetosonic Waves in a Coronal Loop

We consider impulsively excited magnetosonic waves in a highly magnetized coronal loop that is approximated by a straight plasma slab of enhanced mass density. Numerical results reveal that wavelet spectra of time signatures of these waves possess characteristic shapes that depend on the position of the initial pulse: in the case of a pulse launched inside the slab, these spectra are of a tadpole shape, while for a pulse excited in the ambient medium these spectra display more complex structures with branches of long and short-period waves. These short period oscillations correspond to waves that are trapped inside the slab, and the long-period oscillations are associated with waves that propagate through the ambient medium and reach the detection point. These findings are compatible with recent theoretical studies and observations by the solar eclipse coronal imaging system (SECIS).

Remarkable Disk and Off-Nuclear Starburst Activity in the Tadpole Galaxy as revealed by theSpitzer Space Telescope

We present ground-based optical and Spitzer Space Telescope infrared imaging observations of the interacting galaxy UGC 10214, the Tadpole galaxy (z = 0.0310), focusing on the star formation activity in the nuclear, disk, spiral arms, and tidal tail regions. The ground-based optical data set spans a wavelength range between 0.3 and 0.8 μm, the near-IR data set spans 1–2.2 μm, and the Spitzer IR data set spans 3–70 μm. The major findings of this study are that the Tadpole is actively forming stars in the main disk outside of the nucleus and in the tidal plume, with an estimated mean star formation rate of ~2–4 M⊙ yr-1. The most prominent sites of mid-IR emission define a morphology that, combined with the overall morphology of the system, suggests the interaction may belong to the rare class of off-center collisional ring systems that form both shock-induced rings of star formation and tidal plumes. In stark contrast to the disk star formation, the nuclear emission is solely powered by older stars, with little evidence for ongoing star formation at the center of the Tadpole. Extranuclear star formation accounts for >50% of the total star formation in the disk and spiral arms, featuring infrared-bright spots that exhibit strong polycyclic aromatic hydrocarbon (PAH) emission, the band strength of which is comparable to that of late-type star-forming disk galaxies. The tidal tail, which extends 2' (~75 kpc) into the intergalactic medium, is populated by supermassive star clusters, M ~ 106 M⊙, likely triggered by the galaxy-galaxy interaction that has distorted UGC 10214 into its current tadpole shape. The Tadpole is therefore an example of an off-nuclear or tidal-tail starburst, with several large sites of massive star formation in the disk and in the plume, including the most prominent Hubble Space Telescope–revealed cluster, J160616.85+552640.6. The clusters exhibit remarkable IR properties, including exceptionally strong 24 μm emission relative to the underlying starlight, hot dust continuum, and PAH emission, with an estimated current star formation rate of ~0.1–0.4 M⊙ yr-1, representing >10% of the total star formation in the system. We estimate the mass of the largest cluster to be ~ × 106 M⊙ based on the g'-band (0.5 μm) and near-IR (2.2 μm) integrated fluxes in combination with an assumed mass-to-light ratio appropriate to young clusters, or large enough to be classified as a nascent dwarf galaxy or globular cluster.

Body shape, burst speed and escape behavior of larval anurans

Variation in behavior, morphology and life history traits of larval anurans across predator gradients, and consequences of that variation, have been abundantly studied. Yet the functional link between morphology and burst‐swimming speed is largely unknown. We conducted experiments with two divergent species of anurans, Scaphiopus holbrookii and Rana sphenocephala, to examine how behavior and morphology influence predator vulnerability, and whether tadpole shape is related to burst‐swimming performance. Scaphiopus holbrookii, a species that typically uses ephemeral pools, was more active, exhibited slower burst speeds, and was more susceptible to predation than R. sphenocephala, a species associated with more permanent aquatic sites. Our analysis of morphology and burst speed defined a shared axis of shape variation associated with burst‐swimming speed regardless of species. Tadpoles with a deeper tail fin and muscle and a smaller body produced faster speeds. The nature and breadth of the morphology–speed relationship suggests it may represent a generalized ecomorphological paradigm for larval anurans.

Large‐Scale Nonhydrolytic Sol–Gel Synthesis of Uniform‐Sized Ceria Nanocrystals with Spherical, Wire, and Tadpole Shapes

Sei kein Frosch! Nanokristalle aus Cerdioxid mit einheitlicher Größe und sphärischer, drahtförmiger oder Kaulquappen-förmiger Gestalt wurden aus einer nichthydrolytischen Sol-Gel-Reaktion von Cer(III)-nitrat und Diphenylether in Gegenwart geeigneter Tenside erhalten. Im Bild sind TEM-Aufnahmen von Kaulquappen-förmigen Nanodrähten gezeigt: mehrere Drähte unten links, ein einzelner Draht niedrig (rechts) und hochaufgelöst (oben links).

Large‐Scale Nonhydrolytic Sol–Gel Synthesis of Uniform‐Sized Ceria Nanocrystals with Spherical, Wire, and Tadpole Shapes

Large‐Scale Nonhydrolytic Sol–Gel Synthesis of Uniform‐Sized Ceria Nanocrystals with Spherical, Wire, and Tadpole Shapes

Scaling Theory of Diblock Polyampholyte Solutions

We have developed a scaling theory for a salt-free solution of diblock polyampholytes. A charge-symmetric diblock polyampholyte chain with equally charged positive and negative blocks collapses into a globule. This collapse is driven by the electrostatic attraction between oppositely charged blocks. We predict that a charge-asymmetric block polyampholyte has a tadpole shape with a globular head and a polyelectrolyte tail. These tadpoles aggregate into micelles if the electrostatic repulsion between their tails is weaker than the surface energy gain due to aggregation of their heads. First tadpoles form double-tailed micelles. In double-tailed micelles with an aggregation number larger than two, additional chains are completely confined into the core, and the length of the two tails increases proportionally to the total charge of the micelle. If this total charge becomes higher than the charge of two corona blocks of double-tailed micelles, more blocks appear in the corona. Chains are disproportionated in ...

Temporal variation in predation risk: stage‐dependency, graded responses and fitness costs in tadpole antipredator defences

Temporal variation in predation risk may be an important determinant of prey antipredator behaviours. According to the risk allocation hypothesis, the strongest antipredator behaviours are expected when periods of high risk are short and infrequent. We tested this prediction in a laboratory experiment where common frog Rana temporaria tadpoles were raised form early larval stages until metamorphosis. We manipulated the time a predatory Aeshna dragonfly larva was present and recorded behavioural responses (activity) of the tadpoles at three different time points during the tadpoles’ development. We also investigated how tadpole shape, size and age at metamorphosis were affected by temporal variation in predation risk. We found that during the two first time points activity was always lowest in the constant high‐risk situation. However, antipredator response in the two treatments with brief high‐risk situation increased as tadpoles developed, and by the third time point, when the tadpoles were close to metamorphosis, activity was as low as in the constant high‐risk situation. Exposure to chemical cues of a predation event tended to reduce activity during the first time period, but caused no response later on. Induced morphological changes (deeper tail and shorter relative body length) were graded the response being stronger as the time spent in the proximity of predator increased. Tadpoles in the brief risk and chemical cue treatments showed intermediate responses. Modification of life history was only found in the constant high‐risk treatment in which tadpoles had longer larval period and larger metamorphic size. Our results indicate that both behavioural and morphological defences were sensitive to temporal variation in predation risk, but behaviour did not respond in the manner predicted by the risk allocation model. We discuss the roles of concentration of predator chemical cues and prey stage‐dependency in determining these responses.

Synthesis and properties of tadpole-shaped gold nanoparticles.

In this communication, gold nanoparticles with a tadpole shape were synthesized by a simple aqueous-phase chemical method. The unusual three-dimensional and crystallized structures were demonstrated by TEM, AFM, and HRTEM methods. The SEM and UV-visible absorption measurements and electrophoresis experiments revealed that the tadpoles had novel optical and electrical properties. These attractive structures and properties are expected to find uses in many fields such as electrics, optics, electrochemistry, and biological sensing.

Investigation of the long-periodic orbits of Trojan-type asteroids in the outer solar system

The present paper demonstrates the results of the numerical integration of equations of motion of a infinitesimal mass pleased in the neighborhood of the triangular point of the Sun-planet system. There are presented the results for the outer solar system, i.e. for Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The long-periodic solutions were searched for the distance from the Lagrangian point changing from ±0.01 to ±0.10 in canonical units. The Trojans of those planets have the circle, tadpole, horseshoe and irregular shape of their orbits. Same of those test particles showed a close approach to planet. Other of those collided with planet and then was removed from the solar system. The tadpole, circle and same trajectories surveyed integration for 100,000 years.

Predator-induced morphological changes in an amphibian: predation by dragonflies affects tadpole shape and color.

Predator-induced defenses are well studied in plants and invertebrate animals, but have only recently been recognized in vertebrates. Gray treefrog (Hylachrysoscelis) tadpoles reared with predatory dragonfly (Aeshnaumbrosa) larvae differ in shape and color from tadpoles reared in the absence of dragonflies. By exposing tadpoles to tail damage and the non-lethal presence of starved and fed dragonflies, we determined that these phenotypic differences are induced by non-contact cues present when dragonflies prey on Hyla. The induced changes in shape are in the direction that tends to increase swimming speed; thus, the induced morphology may help tadpoles evade predators. Altering morphology in response to predators is likely to influence interactions with other species in the community as well.

A computational fluid dynamics study of tadpole swimming

The hydrodynamics and undulating propulsion of tadpoles were studied using a newly developed two-dimensional computational fluid dynamics (CFD) modeling method. The mechanism of thrust generation associated with the flow patterns during swimming is discussed. Our CFD analysis shows that the kinematics of tadpoles is specifically matched to their special shape and produces a jet-stream propulsion with high propulsive efficiency, as high as that achieved by teleost fishes. Investigation of the effect of Reynolds number indicates that the Froude efficiency increases with increasing Reynolds number with no ceiling in generating the jet-stream propulsion. Further studies using tadpole- and fish-shaped models with hindlimbs added to their body profiles reveal that the tadpole shape ­ a globose head with a tapered tail and hindlimbs at the base of the tail ­ allows tadpoles, but not fish, to develop hindlimbs with very little handicap on propulsion. The shapes and kinematics of tadpoles appear to be specially adapted to the requirement of these organisms to transform into frogs.