Orbital cellulitis associated with Toxocara canis in a dog

Reports of Toxocara canis ocular larva migrans are uncommon in animals, with only a few cases reported. Most reports involve larval migration into the retina and choroid, with parasitic invasion of the orbit reported only in experimental studies. This is the first clinical case of Toxocara canis infection in the retrobulbar region of a 10-year-old, cross-bred male dog presenting with unilateral orbital cellulitis. Ophthalmic signs included protrusion of the nictitating membrane, chemosis, exophthalmos and hypertropia. The parasite was diagnosed by histologic and parasitologic examination of orbital tissues, which were removed during enucleation.

Odontogenic infection causing orbital cellulitis in a pediatric patient

Odontogenic abscess can become an orbital cellulitis, causing potentially serious intracranial and orbital complications. The full clinical complications from odontogenic orbital cellulitis in a pediatric patient are rarely seen daily in hospital emergency departments. Thus, odontogenic orbital cellulitis still remains a rarity, resulting in a medical challenge. With this in mind, this study aimed to describe a case of periorbital and orbital cellulitis resulting from odontogenic origin in a 6-year-old patient who was successfully treated by performing intravenous antibiotic administration combined with surgical drainage. Copyright © 2013 by Mutaz B. Habal, MD.

Paranasal sinus infection causing orbital subperiosteal abscess: Surgical management of this devastating entity

Background: Orbital infection is an uncommon devastating infection and is usually a complication of paranasal sinus infection. Without appropriate treatment, orbital infection may lead to serious complications, even death. Prompt treatment is mandatory to avoid visual loss or intracranial complications. The literature shows that initially, intravenous antibiotics should be administered, and after 48 h, if no improvement appears, the affected orbit and the sinuses must be surgically drained. The authors describe two cases of orbital cellulitis with a brief literature review. Case report: The authors describe two cases of orbital abscess caused by paranasal sinus infection. In case 1, the patient presented a decreased visual acuity associated with ophthalmoplegia of the right eye. In case 2, the patient presented a decreased visual acuity. Thus, administration of intravenous antibiotic combined with surgical drainage was performed. After surgical procedure, eye movements were normalized in case 1, and in both patients, the visual acuity returned to normal parameters. Discussion: The authors recommend early surgical drainage with parenteral antibiotic administration and careful postoperative observations by monitoring the signs and symptoms of the orbital complaint. © 2012 Springer-Verlag.

Mucopiocelo fronto-etmoidal, a propósito de um caso clínico

O mucocelo é uma lesão quística, benigna, expansiva dos seios perinasais. A sobreinfecção deste, designada de mucopiocelo, pode levar a um período de crescimento rápido, com maior risco de complicações. Relata-se o caso clínico de uma doente do sexo feminino, 59 anos, que recorreu ao Serviço de Urgência após crise inaugural de convulsão tónico-clónica generalizada, com queixas de aumento de volume periorbitário direito e febre desde há 1 semana. Apresentava à direita celulite orbitária e proptose ínfero-externa, com área de flutuação na parte medial da pálpebra superior, oftalmoplegia e quemose do olho direito acompanhada de rinorreia mucopurulenta. Realizou TC que demonstrou volumoso abcesso subperiosteal direito, ao nível da parede medial da órbita, tendo como ponto de partida aparente as células etmoidais anteriores homolaterais e seio frontal direito. Colocou-se a hipótese de mucopiocelo fronto-etmoidal. Foi submetida a drenagem de urgência do abcesso e a cirurgia endoscópica nasal com marsupialização da lesão fronto-etmoidal. Verificou-se resolução completa do quadro clínico. Apesar de consideradas lesões benignas, os mucocelos, apresentam potencial destrutivo, principalmente se infectados, necessitando, por vezes, de intervenção cirúrgica de urgência. A abordagem endoscópica destas lesões reafirma-se como tratamento de eleição.

Time-Dependent Density Functional Molecular Orbital and Excited State Calculations on Bis(porphyrinyl)butadiynes in the Monocationic, Neutral, Monoanionic, and Dianionic Oxidation States

We report a theoretical study of the multiple oxidation states (1+, 0, 1−, and 2−) of a meso,meso-linked diporphyrin, namely bis[10,15,20-triphenylporphyrinatozinc(II)-5-yl]butadiyne (4), using Time-Dependent Density Functional Theory (TDDFT). The origin of electronic transitions of singlet excited states is discussed in comparison to experimental spectra for the corresponding oxidation states of the close analogue bis{10,15,20-tris[3‘,5‘-di-tert-butylphenyl]porphyrinatozinc(II)-5-yl}butadiyne (3). The latter were measured in previous work under in situ spectroelectrochemical conditions. Excitation energies and orbital compositions of the excited states were obtained for these large delocalized aromatic radicals, which are unique examples of organic mixed-valence systems. The radical cations and anions of butadiyne-bridged diporphyrins such as 3 display characteristic electronic absorption bands in the near-IR region, which have been successfully predicted with use of these computational methods. The radicals are clearly of the “fully delocalized” or Class III type. The key spectral features of the neutral and dianionic states were also reproduced, although due to the large size of these molecules, quantitative agreement of energies with observations is not as good in the blue end of the visible region. The TDDFT calculations are largely in accord with a previous empirical model for the spectra, which was based simplistically on one-electron transitions among the eight key frontier orbitals of the C4 (1,4-butadiyne) linked diporphyrins.

Super-orbital re-entry in Australia : laboratory measurement, simulation and flight observation

There are large uncertainties in the aerothermodynamic modelling of super-orbital re-entry which impact the design of spacecraft thermal protection systems (TPS). Aspects of the thermal environment of super-orbital re-entry flows can be simulated in the laboratory using arc- and plasma jet facilities and these devices are regularly used for TPS certification work [5]. Another laboratory device which is capable of simulating certain critical features of both the aero and thermal environment of super-orbital re-entry is the expansion tube, and three such facilities have been operating at the University of Queensland in recent years[10]. Despite some success, wind tunnel tests do not achieve full simulation, however, a virtually complete physical simulation of particular re-entry conditions can be obtained from dedicated flight testing, and the Apollo era FIRE II flight experiment [2] is the premier example which still forms an important benchmark for modern simulations. Dedicated super-orbital flight testing is generally considered too expensive today, and there is a reluctance to incorporate substantial instrumentation for aerothermal diagnostics into existing missions since it may compromise primary mission objectives. An alternative approach to on-board flight measurements, with demonstrated success particularly in the ‘Stardust’ sample return mission, is remote observation of spectral emissions from the capsule and shock layer [8]. JAXA’s ‘Hayabusa’ sample return capsule provides a recent super-orbital reentry example through which we illustrate contributions in three areas: (1) physical simulation of super-orbital re-entry conditions in the laboratory; (2) computational simulation of such flows; and (3) remote acquisition of optical emissions from a super-orbital re entry event.

Image-based visual servoing for the super-orbital re-entry of Hayabusa spacecraft

This paper presents an image-based visual servoing system that was used to track the atmospheric Earth re-entry of Hayabusa. The primary aim of this ground based tracking platform was to record the emission spectrum radiating from the superheated gas of the shock layer and the surface of the heat shield during re-entry. To the author's knowledge, this is the first time that a visual servoing system has successfully tracked a super-orbital re-entry of a spacecraft and recorded its pectral signature. Furthermore, we improved the system by including a simplified dynamic model for feed-forward control and demonstrate improved tracking performance on the International Space Station (ISS). We present comparisons between simulation and experimental results on different target trajectories including tracking results from Hayabusa and ISS. The required performance for tracking both spacecraft is demanding when combined with a narrow field of view (FOV). We also briefly discuss the preliminary results obtained from the spectroscopy of the Hayabusa's heat shield during re-entry.

Switching radical stability by pH-induced orbital conversion

In most radicals the singly occupied molecular orbital (SOMO) is the highest-energy occupied molecular orbital (HOMO); however, in a small number of reported compounds this is not the case. In the present work we expand significantly the scope of this phenomenon, known as SOMO-HOMO energy-level conversion, by showing that it occurs in virtually any distonic radical anion that contains a sufficiently stabilized radical (aminoxyl, peroxyl, aminyl) non-pi-conjugated with a negative charge (carboxylate, phosphate, sulfate). Moreover, regular orbital order is restored on protonation of the anionic fragment, and hence the orbital configuration can be switched by pH. Most importantly, our theoretical and experimental results reveal a dramatically higher radical stability and proton acidity of such distonic radical anions. Changing radical stability by 3-4 orders of magnitude using pH-induced orbital conversion opens a variety of attractive industrial applications, including pH-switchable nitroxide-mediated polymerization, and it might be exploited in nature.

Single layer lead iodide: Computational exploration of structural, electronic and optical properties, strain induced band modulation and the role of spin-orbital-coupling

Graphitic like layered materials exhibit intriguing electronic structures and thus the search for new types of two-dimensional (2D) monolayer materials is of great interest for developing novel nano-devices. By using density functional theory (DFT) method, here we for the first time investigate the structure, stability, electronic and optical properties of monolayer lead iodide (PbI2). The stability of PbI2 monolayer is first confirmed by phonon dispersion calculation. Compared to the calculation using generalized gradient approximation, screened hybrid functional and spin–orbit coupling effects can not only predicts an accurate bandgap (2.63 eV), but also the correct position of valence and conduction band edges. The biaxial strain can tune its bandgap size in a wide range from 1 eV to 3 eV, which can be understood by the strain induced uniformly change of electric field between Pb and I atomic layer. The calculated imaginary part of the dielectric function of 2D graphene/PbI2 van der Waals type hetero-structure shows significant red shift of absorption edge compared to that of a pure monolayer PbI2. Our findings highlight a new interesting 2D material with potential applications in nanoelectronics and optoelectronics.

The impact of orbital errors on the estimation of satellite clock errors and PPP

Precise satellite orbit and clocks are essential for providing high accuracy real-time PPP (Precise Point Positioning) service. However, by treating the predicted orbits as fixed, the orbital errors may be partially assimilated by the estimated satellite clock and hence impact the positioning solutions. This paper presents the impact analysis of errors in radial and tangential orbital components on the estimation of satellite clocks and PPP through theoretical study and experimental evaluation. The relationship between the compensation of the orbital errors by the satellite clocks and the satellite-station geometry is discussed in details. Based on the satellite clocks estimated with regional station networks of different sizes (∼100, ∼300, ∼500 and ∼700 km in radius), results indicated that the orbital errors compensated by the satellite clock estimates reduce as the size of the network increases. An interesting regional PPP mode based on the broadcast ephemeris and the corresponding estimated satellite clocks is proposed and evaluated through the numerical study. The impact of orbital errors in the broadcast ephemeris has shown to be negligible for PPP users in a regional network of a radius of ∼300 km, with positioning RMS of about 1.4, 1.4 and 3.7 cm for east, north and up component in the post-mission kinematic mode, comparable with 1.3, 1.3 and 3.6 cm using the precise orbits and the corresponding estimated clocks. Compared with the DGPS and RTK positioning, only the estimated satellite clocks are needed to be disseminated to PPP users for this approach. It can significantly alleviate the communication burdens and therefore can be beneficial to the real time applications.

Structure of the benzene center dot center dot center dot ICI complex: A UVPES and ab initio molecular orbital study

UVPES studies and ab initio and DFT computations have been done on the benzene...ICl complex; electron spectral data and computed orbital energies show that donor orbitals are stabilized and acceptor orbitals are destabilized due to complexation. Calculations predict an oblique structure for the complex in which the interacting site is a C=C bond center in the donor and iodine atom in the acceptor, in full agreement with earlier experimental reports. BSSE-corrected binding energies closely match the enthalpy of complexation reported, and the NBO analysis clearly reveals the involvement of the pi orbital of benzene and the sigma* orbital of ICl in the complex.

Nucleophilic additions to 4-substituted snoutanones: getting a measure of long range electrostatic and orbital control of pi-face selectivity

Pentacyclic ketones 10a-e (snoutan-9-ones) undergo nucleophilic additions with the same facial preference as the corresponding norsnoutanones 9a-e, but with markedly reduced selectivity, revealing the involvement of electrostatic effects in the former and implying the importance of hyperconjugative orbital interactions in determining pi-face selectivity in the latter systems.