Defining target volumes for stereotactic ablative radiotherapy of early-stage lung tumours: a comparison of three-dimensional 18F-fluorodeoxyglucose positron emission tomography and four-dimensional computed tomography.:PETCT versus 4DCT for SABR in Early Stage NSCLC

AIMS: High local control rates are achieved in stage I lung cancer using
stereotactic ablative radiotherapy. Target delineation is commonly based on
four-dimensional computed tomography (CT) scans. Target volumes defined by
positron emission tomography/computed tomography (PET/CT) are compared with those defined by four-dimensional CT and conventional ('three-dimensional')
(18)F-fluorodeoxyglucose ((18)F-FDG) PET/CT.

MATERIALS AND METHODS: For 16 stage I non-small cell lung cancer tumours, six
approaches for deriving PET target volumes were evaluated: manual contouring,
standardised uptake value (SUV) absolute threshold of 2.5, 35% of maximum SUV
(35%SUV(MAX)), 41% of SUV(MAX) (41%SUV(MAX)) and two different source to
background ratio techniques (SBR-1 and SBR-2). PET-derived target volumes were compared with the internal target volume (ITV) from the modified maximum
intensity projection (MIP(MOD) ITV). Volumetric and positional correlation was
assessed using the Dice similarity coefficient (DSC).

RESULTS: PET-based target volumes did not correspond to four-dimensional CT-based target volumes. The mean DSC relative to MIP(MOD) ITV were: PET manual = 0.64, SUV2.5 = 0.64, 35%SUV(MAX) = 0.63, 41%SUV(MAX) = 0.57. SBR-1 = 0.52, SBR-2 =0.49. PET-based target volumes were smaller than corresponding MIP ITVs.

CONCLUSIONS: Conventional three-dimensional (18)F-FDG PET-derived target volumes for lung stereotactic ablative radiotherapy did not correspond well with those derived from four-dimensional CT, including those in routine clinical use
(MIP(MOD) ITV). Caution is required in using three-dimensional PET for motion
encompassing target volume delineation.

Three dimensional morphology and compressive behaviour of sintered biodegradable composite scaffolds

Porous poly-L-lactide acid (PLA) scaffolds are prepared using polymer sintering and porogen leaching method. Different weight fractions of the Hydroxyapatite (HA) are added to the PLA to control the acidity and degradation rate. The three dimensional morphology and surface porosity are tested using micro CT, optical microscopy and scanning electron microscopy (SEM). Results indicate that the surface porosity does not change by addition of HA. The micro Ct examinations show slight decrease in the pore size and increase in wall thickness accompanied with reduced anisotropy for the scaffolds containing HA. SEM micrographs show detectable interconnected pores for the scaffold with pure PLA. Addition of the HA results in agglomeration of the HA which blocks some of the pores. Compression tests of the scaffold identify three stages in the stress-strain curve. The addition of HA adversely affects the modulus of the scaffold at the first stage, but this was reversed for the second and third stages of the compression. The results of these tests are compared with the cellular material model. The manufactured scaffold have acceptable properties for a scaffold, however improvement to the mixing of the phases of PLA and HA is required to achieve better integrity of the composite scaffolds.

Analysis of the compressive behaviour of the three-dimensional printed porous titanium for dental implants using a modified cellular solid model

A set of cylindrical porous titanium test samples were produced using the three-dimensional printing and sintering method with samples sintered at 900 °C, 1000 °C, 1100 °C, 1200 °C or 1300 °C. Following compression testing, it was apparent that the stress-strain curves were similar in shape to the curves that represent cellular solids. This is despite a relative density twice as high as what is considered the threshold for defining a cellular solid. As final sintering temperature increased, the compressive behaviour developed from being elastic-brittle to elastic-plastic and while Young's modulus remained fairly constant in the region of 1.5 GPa, there was a corresponding increase in 0.2% proof stress of approximately 40-80 MPa. The cellular solid model consists of two equations that predict Young's modulus and yield or proof stress. By fitting to experimental data and consideration of porous morphology, appropriate changes to the geometry constants allow modification of the current models to predict with better accuracy the behaviour of porous materials with higher relative densities (lower porosity).

Synthetic light curves and spectra for three-dimensional delayed-detonation models of type ia supernovae

In a companion paper, Seitenzahl et al. have presented a set of three-dimensional delayed detonation models for thermonuclear explosions of near-Chandrasekhar-mass white dwarfs (WDs). Here,we present multidimensional radiative transfer simulations that provide synthetic light curves and spectra for those models. The model sequence explores both changes in the strength of the deflagration phase (which is controlled by the ignition configuration in our models) and the WD central density. In agreement with previous studies, we find that the strength of the deflagration significantly affects the explosion and the observables. Variations in the central density also have an influence on both brightness and colour, but overall it is a secondary parameter in our set of models. In many respects, the models yield a good match to the observed properties of normal Type Ia supernovae (SNe Ia): peak brightness, rise/decline time-scales and synthetic spectra are all in reasonable agreement. There are, however, several differences. In particular, the models are systematically too red around maximum light, manifest spectral line velocities that are a little too high and yield I-band light curves that do not match observations. Although some of these discrepancies may simply relate to approximations made in the modelling, some pose real challenges to the models. If viewed as a complete sequence, our models do not reproduce the observed light-curve width- luminosity relation (WLR) of SNe Ia: all our models show rather similar B-band decline rates, irrespective of peak brightness. This suggests that simple variations in the strength of the deflagration phase in Chandrasekhar-mass deflagration-to-detonation models do not readily explain the observed diversity of normal SNe Ia. This may imply that some other parameter within the Chandrasekhar-mass paradigm is key to the WLR, or that a substantial fraction of normal SNe Ia arise from an alternative explosion scenario.

Electrowetting movement of an aqueous droplet between two three-dimensional electrode surfaces

In an effort to develop a novel electronic paper image display technology based on the electrowetting principle, a 3-D electrowetting cell is designed and fabricated, which consists of two 3-D bent electrodes, each having a horizontal surface made of gold and a vertical surface made of indium tin oxide (ITO) glass as a color display window, a layer of dielectric material on the 3-D electrodes, and a highly fluorinated hydrophobic layer on the surface of the dielectric layer. Results of this work show that an electrowetting-induced motion of an aqueous droplet in immiscible oils can be achieved reversibly across the boundary of the horizontal and vertical surfaces of the 3-D electrode surface. It is also shown that the droplet can maintain its wetting state on a vertical sidewall electrode free of a power supplier when the voltage is removed. This phenomenon may form the basis for color contrast modulation applications, where a power-free image display is required, such as electronic paper display technology in the future. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3100201]

Investigating Approaches to Three-Dimensional Printing of Hydroxyapatite Scaffolds for Bone Regeneration

This study investigated the feasibility of manufacturing hydroxyapatite (HA)-based scaffolds using 3D printing technology by incorporating different binding additives, such as maltodextrin and polyvinyl alcohol (PVOH), into the powder formulation. Different grades of PVOH were evaluated in terms of their impact on the printing quality. Results showed that scaffolds with high architectural accuracy in terms of the design and excellent green compressive strength were obtained when the PVOH (high viscosity) was used as the binding additive for HA.

Analysis of a three-dimensional flow generated by a linear aerospike

Linear aerospike nozzles are envisaged as a possible means to improve launcher engine performance. One of the most interesting properties of these nozzles is the possibility of a good integration with the vehicle. To improve the knowledge of the flow-field and performance of aerospike nozzles, they are studied numerically, with particular attention to the differences between the basic two-dimensional nozzle, usually considered in the design phase, and the more realistic three-dimensional nozzle. The study considers also the effect of flight condition, which cannot be neglected because of the characteristic external expansion of aerospike nozzles.

Three-dimensional modeling of the human fallopian tube fimbriae

OBJECTIVE: Ovarian cancer is the most lethal gynecological malignancy that affects women. Recent data suggests that the disease may originate in the fallopian fimbriae; however, the anatomical origin of ovarian carcinogenesis remains unclear. This is largely driven by our lack of knowledge regarding the structure and function of normal fimbriae and the relative paucity of models that accurately recapitulate the in vivo fallopian tube. Therefore, a human three-dimensional (3D) culture system was developed to examine the role of the fallopian fimbriae in serous tumorigenesis.

METHODS: Alginate matrix was utilized to support human fallopian fimbriae ex vivo. Fimbriae were cultured with factors hypothesized to contribute to carcinogenesis, namely; H2O2 (1mM) a mimetic of oxidative stress, insulin (5μg/ml) to stimulate glycolysis, and estradiol (E2, 10nM) which peaks before ovulation. Cultures were evaluated for changes in proliferation and p53 expression, criteria utilized to identify potential precursor lesions. Further, secretory factors were assessed after treatment with E2 to identify if steroid signaling induces a pro-tumorigenic microenvironment.

RESULTS: 3D fimbriae cultures maintained normal tissue architecture up to 7days, retaining both epithelial subtypes. Treatment of cultures with H2O2 or insulin significantly induced proliferation. However, p53 stabilization was unaffected by any particular treatment, although it was induced by ex vivo culturing. Moreover, E2-alone treatment significantly induced its canonical target PR and expression of IL8, a factor linked to poor outcome.

CONCLUSIONS: 3D alginate cultures of human fallopian fimbriae provide an important microphysiological model, which can be further utilized to investigate serous tumorigenesis originating from the fallopian tube.

An effective three-dimensional ordered mesoporous ZnCo2O4 as electrocatalyst for Li-O2 batteries

Three-dimensional ordered mesoporous (3DOM) ZnCo₂O₄ materials have been synthesized via a hard template and used as bifunctional electrocatalysts for rechargeable Li-O₂ batteries. The as-prepared ZnCo₂O₄ nanoparticles possess a high specific surface area of 127.2 m² g^-1 and a spinel crystalline structure. The Li-O₂ battery utilizing 3DOM ZnCo₂O₄ shows a higher specific capacity of 6024 mAh g^-1 than that with pure Ketjen black (KB). Moreover, the ZnCo₂O₄-based electrode enables much enhanced cyclability with a smaller discharge-recharge voltage gap than that of the carbon-only cathode. Such excellent catalytic performance of ZnCo₂O₄ could be associated with its larger surface area and 3D ordered mesoporous structure

Three-dimensional graphene-Co3O4 cathodes for rechargeable Li-O2 batteries

A three-dimensional (3D) graphene-Co₃O₄ electrode was prepared by a two-step method in which graphene was initially deposited on a Ni foam with Co₃O₄ then grown on the resulting graphene structure. Cross-linked Co₃O₄ nanosheets with an open pore structure were fully and vertically distributed throughout the graphene skeleton. The free-standing and binder-free monolithic electrode was used directly as a cathode in a Li-O₂ battery. This composite structure exhibited enhanced performance with a specific capacity of 2453 mA h g^-1 at 0.1 mA cm^-2 and 62 stable cycles with 583 mA h g^-1 (1000 mA h g_carbon^-1). The excellent electrochemical performance is associated with the unique architecture and superior catalytic activity of the 3D electrode. 

Gamma-ray diagnostics of Type Ia supernovae. Predictions of observables from three-dimensional modeling

Context. Although the question of progenitor systems and detailed explosion mechanisms still remains a matter of discussion, it is commonly believed that Type Ia supernovae (SNe Ia) are production sites of large amounts of radioactive nuclei. Even though the gamma-ray emission due to radioactive decays is responsible for powering the light curves of SNe Ia, gamma rays themselves are of particular interest as a diagnostic tool because they directly lead to deeper insight into the nucleosynthesis and the kinematics of these explosion events. Aims: We study the evolution of gamma-ray line and continuum emission of SNe Ia with the objective of analyzing the relevance of observations in this energy range. We seek to investigate the chances for the success of future MeV missions regarding their capabilities for constraining the intrinsic properties and the physical processes of SNe Ia. Methods: Focusing on two of the most broadly discussed SN Ia progenitor scenarios - a delayed detonation in a Chandrasekhar-mass white dwarf (WD) and a violent merger of two WDs - we used three-dimensional explosion models and performed radiative transfer simulations to obtain synthetic gamma-ray spectra. Both chosen models produce the same mass of 56Ni and have similar optical properties that are in reasonable agreement with the recently observed supernova SN 2011fe. We examine the gamma-ray spectra with respect to their distinct features and draw connections to certain characteristics of the explosion models. Applying diagnostics, such as line and hardness ratios, the detection prospects for future gamma-ray missions with higher sensitivities in the MeV energy range are discussed. Results: In contrast to the optical regime, the gamma-ray emission of our two chosen models proves to be quite different. The almost direct connection of the emission of gamma rays to fundamental physical processes occurring in SNe Ia permits additional constraints concerning several explosion model properties that are not easily accessible within other wavelength ranges. Proposed future MeV missions such as GRIPS will resolve all spectral details only for nearby SNe Ia, but hardness ratio and light curve measurements still allow for a distinction of the two different models at 10 Mpc and 16 Mpc for an exposure time of 106 s. The possibility of detecting the strongest line features up to the Virgo distance will offer the opportunity to build up a first sample of SN Ia detections in the gamma-ray energy range and underlines the importance of future space observatories for MeV gamma rays.