Numerical Evaluation of Microwave Thermal Ablation to Treat Small Adrenocortical Masses

In this paper microwave thermal ablation is numerically evaluated in the context of a treatment for Conn’s Syndrome. This condition is caused by a benign shallow tumour in the cortex of adrenal gland. The modelling and design of microwave applicator to deliver thermal ablation to the adrenal gland requires accurate tissue characterisation. Measuring the dielectric properties of the constituent tissues in the adrenal gland, i.e. cortex and medulla, enables more accurate numerical modelling for electromagnetic and thermal simulations. This study presents an anatomically and dielectrically realistic numerical model of the adrenal gland, and investigates the feasibility of applying controlled heating to small targets in the adrenal cortex. In addition, the use of dielectric contrast between the fat and the cortex of the adrenal gland to focus the thermal energy in the gland has also been studied. Being conscious of limitations of numerical simulation of complex multiphysics problems like the microwave ablative treatment, calculated results provide a preliminary description of the electromagnetic and thermal phenomena involved

Case report of a phantom pheochromocytoma

Plasma free metanephrines or urinary fractionated metanephrines are the biochemical tests of choice for the diagnosis of pheochromocytoma as they have greater sensitivity and specificity than catecholamines for pheochromocytoma detection. This case highlights the preanalytical factors which can influence metanephrine measurement and cause a false positive result. It describes a patient with a high pre-test probability of pheochromocytoma due to hypertension and a past medical history of adrenalectomy for a purported pheochromocytoma in her home country. When biochemical screening revealed grossly elevated urine normetanephrine in the presence of a previously identified right adrenal lesion, there was high clinical suspicion of a pheochromocytoma. However, functional imaging did not support this view which prompted additional testing with plasma metanephrines. Results for plasma and urine metanephrines were discordant and preanalytical drug interference was suspected. Patient medications were reviewed and sulfasalazine, an anti-inflammatory drug was identified as the most likely analytical interferent. Urinary fractionated metanephrines were re-analysed using liquid chromatography tandem mass spectrometry (LC-MS/MS) and all metanephrines were within their reference intervals. This case illustrates how method-specific analytical drug interference prompted unnecessary expensive imaging, heightened patient anxiety and resulted in lengthy investigations for what turned out to be a phantom pheochromocytoma

Spitzer-IRS Spectroscopy of the Prototypical Starburst Galaxy NGC7714

We present observations of the starburst galaxy NGC 7714 with the Infrared Spectrograph IRS on board the Spitzer Space Telescope. The spectra yield a wealth of ionic and molecular features that allow a detailed characterization of its properties. NGC 7714 has an HII region-like spectrum with strong PAH emission features. We find no evidence for an obscured active galactic nucleus, and with [NeIII]/[NeII]~0.73, NGC7714 lies near the upper end of normal-metallicity starburst galaxies. With very little slicate absorption and a temperature of the hottest dust component of 340K, NGC 7714 is the perfect template for a young, unobscured starburstComment: To appear in the special ApJSS issue on early results from Spitze

Contribution of the cyclic nucleotide gated channel subunit, CNG-3, to olfactory plasticity in Caenorhabditis elegans.

In Caenorhabditis elegans, the AWC neurons are thought to deploy a cGMP signaling cascade in the detection of and response to AWC sensed odors. Prolonged exposure to an AWC sensed odor in the absence of food leads to reversible decreases in the animal's attraction to that odor. This adaptation exhibits two stages referred to as short-term and long-term adaptation. Previously, the protein kinase G (PKG), EGL-4/PKG-1, was shown necessary for both stages of adaptation and phosphorylation of its target, the beta-type cyclic nucleotide gated (CNG) channel subunit, TAX-2, was implicated in the short term stage. Here we uncover a novel role for the CNG channel subunit, CNG-3, in short term adaptation. We demonstrate that CNG-3 is required in the AWC for adaptation to short (thirty minute) exposures of odor, and contains a candidate PKG phosphorylation site required to tune odor sensitivity. We also provide in vivo data suggesting that CNG-3 forms a complex with both TAX-2 and TAX-4 CNG channel subunits in AWC. Finally, we examine the physiology of different CNG channel subunit combinations

Novel Techniques in the Assessment of Sports-Related Traumatic Brain Injury

Mild traumatic brain injuries (mTBI) or concussions are a substantial health concern, particularly in collision and contact sports. Consequently, there is growing concern regarding the acute and chronic effects of repeated brain trauma. Traditional assessment of mTBI has been based on clinical or computed tomography (CT) assessments followed by a period of in-hospital observation in some cases. These may have significant time and cost implications while potentially exposing patients to ionizing radiation and providing a low sensitivity and specificity. Recent advancements have focused on novel modalities that may potentially predict early and long-term sequelae from mTBI with greater accuracy and provide the optimum personalized treatment plan in collaboration with the athlete. This chapter will outline state of the art in these modalities, from salivary and blood biomarkers imaging and neuropsychology assessments, and discuss their translational applicability to the clinical setting

Online leadership discourse in higher education: a digital multimodal discourse perspective

As leadership discourses in higher education are increasingly being mediated online, texts previously reserved for staff are now being made available in the public domain. As such, these texts become accessible for study, critique and evaluation. Additionally, discourses previously confined to the written domain are now increasingly multimodal. Thus, an approach is required that is capable of relating detailed, complex multimodal discourse analyses to broader sociocultural perspectives to account for the complex meaning-making practices that operate in online leadership discourses. For this purpose, a digital multimodal discourse approach is proposed and illustrated via a small-scale case study of the online leadership discourse of an Australian university. The analysis of two short video texts demonstrates how a digital multimodal discourse perspective facilitates the identification of key multimodal systems used for meaning-making in online communication, how meaning arises through combinations of semiotic choices (not individual choices), and how the results of multimodal discourse analysis using digital technology can reveal larger sociocultural patterns – in this case, divergent leadership styles and approaches as reflected in online discourse, at a time of immense change within the higher education sector

Models of the Morphology, Kinematics, and Star Formation History of the Prototypical Collisional Starburst System: NGC 7714/7715 = Arp 284

(abridged) We present new N-body, hydrodynamical simulations of the interaction between the starburst galaxy NGC 7714 and its post-starburst companion NGC 7715, focusing on the formation of the collisional features, including: 1) the gas-rich star forming bridge, 2) the large gaseous loop (and stellar tails) to the west of the system, 3) the very extended HI tail to the west and north of NGC 7714, and 4) the partial stellar ring in NGC 7714. Our simulations confirm the results of earlier work that an off-center inclined collision between two disk galaxies is almost certainly responsible for the peculiar morphologies of this system. However, we have explored a wider set of initial galaxy and collisional encounter parameters than previously, and have found a relatively narrow range of parameters that reproduce all the major morphologies of this system. The simulations suggest specific mechanisms for the development of several unusual structures. We find that the complex gas bridge has up to four distinct components, with gas contributed from two sides of NGC 7715, as well as from NGC 7714. The observed gas-star offset in this bridge is accounted for in the simulations by the dissipative evolution of the gas. The models also indicate that the low surface brightness HI tail to the far west of NGC 7714 is the end of the NGC 7715 countertail, curved behind the two galaxies. Spectral evolutionary models of the NGC 7714 core by Lan\c{c}on et al. suggest the possibility of multiple starbursts in the last 300 Myr. Our hydrodynamic models suggest that bursts could be triggered by induced ring-like waves, and a post-collision buildup of gas in the core of the galaxy.Comment: 24 pages, 20 figures, accepted for ApJ Supp

New Observations of Extra-Disk Molecular Gas in Interacting Galaxy Systems, Including a Two-Component System in Stephan's Quintet

We present new CO (1 - 0) observations of eleven extragalactic tails and bridges in nine interacting galaxy systems, almost doubling the number of such features with sensitive CO measurements. Eight of these eleven features were undetected in CO to very low CO/HI limits, with the most extreme case being the NGC 7714/5 bridge. This bridge contains luminous H II regions and has a very high HI column density (1.6 X 10^21 cm^-2 in the 55" CO beam), yet was undetected in CO to rms T(R)* = 2.4 mK. The HI column density is higher than standard H2 and CO self-shielding limits for solar-metallicity gas, suggesting that the gas in this bridge is metal-poor and has an enhanced N(H2)/I(CO) ratio compared to the Galactic value. Only one of the eleven features in our sample was unambiguously detected in CO, a luminous HI-rich star formation region near an optical tail in the compact group Stephan's Quintet. We detect CO at two widely separated velocities in this feature, at ~6000 km/s and ~6700 km/s. Both of these components have HI and H-alpha counterparts. These velocities correspond to those of galaxies in the group, suggesting that this gas is material that has been removed from two galaxies in the group. The CO/HI/H-alpha ratios for both components are similar to global values for spiral galaxies.Comment: 39 pages, Latex, 15 figures, Astronomical Journal, in pres

Controls on mangrove forest-atmosphere carbon dioxide exchanges in western Everglades National Park

We report on net ecosystem production (NEP) and key environmental controls on net ecosystem exchange (NEE) of carbon dioxide (CO2) between a mangrove forest and the atmosphere in the coastal Florida Everglades. An eddy covariance system deployed above the canopy was used to determine NEE during January 2004 through August 2005. Maximum daytime NEE ranged from −20 to −25 mmol (CO2) m−2 s−1 between March and May. Respiration (Rd) was highly variable (2.81 ± 2.41 mmol (CO2) m−2 s−1), reaching peak values during the summer wet season. During the winter dry season, forest CO2 assimilation increased with the proportion of diffuse solar irradiance in response to greater radiative transfer in the forest canopy. Surface water salinity and tidal activity were also important controls on NEE. Daily light use efficiency was reduced at high (\u3e34 parts per thousand (ppt)) compared to low (ppt) salinity by 46%. Tidal inundation lowered daytime Rd by ∼0.9 mmol (CO2) m−2 s−1 and nighttime Rd by ∼0.5 mmol (CO2) m−2 s−1. The forest was a sink for atmospheric CO2, with an annual NEP of 1170 ± 127 g C m−2 during 2004. This unusually high NEP was attributed to year‐round productivity and low ecosystem respiration which reached a maximum of only 3 g C m−2 d−1. Tidal export of dissolved inorganic carbon derived from belowground respiration likely lowered the estimates of mangrove forest respiration. These results suggest that carbon balance in mangrove coastal systems will change in response to variable salinity and inundation patterns, possibly resulting from secular sea level rise and climate change. Citation: Barr, J. G., V. Engel, J. D. Fuentes

Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies

We present a study of a large, statistically complete sample of star-forming dwarf galaxies using mid-infrared observations from the {\it Spitzer Space Telescope}. The relationships between metallicity, star formation rate (SFR) and mid-infrared color in these systems show that the galaxies span a wide range of properties. However, the galaxies do show a deficit of 8.0 \um\ polycyclic aromatic hydrocarbon emission as is apparent from the median 8.0 \um\ luminosity which is only 0.004 \lstarf\ while the median $B$-band luminosity is 0.05 \lstarb. Despite many of the galaxies being 8.0 \um\ deficient, there is about a factor of 4 more extremely red galaxies in the [3.6] $-$ [8.0] color than for a sample of normal galaxies with similar optical colors. We show correlations between the [3.6] $-$ [8.0] color and luminosity, metallicity, and to a lesser extent SFRs that were not evident in the original, smaller sample studied previously. The luminosity--metallicity relation has a flatter slope for dwarf galaxies as has been indicated by previous work. We also show a relationship between the 8.0 \um\ luminosity and the metallicity of the galaxy which is not expected given the competing effects (stellar mass, stellar population age, and the hardness of the radiation field) that influence the 8.0 \um\ emission. This larger sample plus a well-defined selection function also allows us to compute the 8.0 \um\ luminosity function and compare it with the one for the local galaxy population. Our results show that below 10$^{9}$ $L$\solar, nearly all the 8.0 \um\ luminosity density of the local universe arises from dwarf galaxies that exhibit strong \ha\ emission -- i.e., 8.0 \um\ and \ha\ selection identify similar galaxy populations despite the deficit of 8.0 \um\ emission observed in these dwarfs.Comment: 13 pages, 11 figures, Published in Ap