RF-sputter fabrication of magnetic garnet thin films and simulation modeling for 1-D magnetic photonic crystal waveguide devices

One dimensional magnetic photonic crystals (1D-MPC) are promising structures for integrated optical isolator applications. Rare earth substituted garnet thin films with proper Faraday rotation are required to fabricate planar 1D-MPCs. In this thesis, flat-top response 1D-MPC was proposed and spectral responses and Faraday rotation were modeled. Bismuth substituted iron garnet films were fabricated by RF magnetron sputtering and structures, compositions, birefringence and magnetooptical properties were studied. Double layer structures for single mode propagation were also fabricated by sputtering for the first time. Multilayer stacks with multiple defects (phase shift) composed of Ce-YIG and GGG quarter-wave plates were simulated by the transfer matrix method. The transmission and Faraday rotation characteristics were theoretically studied. It is found that flat-top response, with 100% transmission and near 45o rotation is achievable by adjusting the inter-defect spacing, for film structures as thin as 30 to 35 μm. This is better than 3-fold reduction in length compared to the best Ce-YIG films for comparable rotations, thus allows a considerable reduction in size in manufactured optical isolators. Transmission bands as wide as 7nm were predicted, which is considerable improvement over 2 defects structure. Effect of repetition number and ratio factor on transmission and Faraday rotation ripple factors for the case of 3 and 4 defects structure has been discussed. Diffraction across the structure corresponds to a longer optical path length. Thus the use of guided optics is required to minimize the insertion losses in integrated devices. This part is discussed in chapter 2 in this thesis. Bismuth substituted iron garnet thin films were prepared by RF magnetron sputtering. We investigated or measured the deposition parameters optimization, crystallinity, surface morphologies, composition, magnetic and magnetooptical properties. A very high crystalline quality garnet film with smooth surface has been heteroepitaxially grown on (111) GGG substrate for films less than 1μm. Dual layer structures with two distinct XRD peaks (within a single sputtered film) start to develop when films exceed this thickness. The development of dual layer structure was explained by compositional gradient across film thickness, rather than strain gradient proposed by other authors. Lower DC self bias or higher substrate temperature is found to help to delay the appearance of the 2nd layer. The deposited films show in-plane magnetization, which is advantageous for waveguide devices application. Propagation losses of fabricated waveguides can be decreased by annealing in an oxygen atmosphere from 25dB/cm to 10dB/cm. The Faraday rotation at λ=1.55μm were also measured for the waveguides. FR is small (10° for a 3mm long waveguide), due to the presence of linear birefringence. This part is covered in chapter 4. We also investigated the elimination of linear birefringence by thickness tuning method for our sputtered films. We examined the compressively and tensilely strained films and analyze the photoelastic response of the sputter deposited garnet films. It has been found that the net birefringence can be eliminated under planar compressive strain conditions by sputtering. Bi-layer GGG on garnet thin film yields a reduced birefringence. Temperature control during the sputter deposition of GGG cover layer is critical and strongly influences the magnetization and birefringence level in the waveguide. High temperature deposition lowers the magnetization and increases the linear birefringence in the garnet films. Double layer single mode structures fabricated by sputtering were also studied. The double layer, which shows an in-plane magnetization, has an increased RMS roughness upon upper layer deposition. The single mode characteristic was confirmed by prism coupler measurement. This part is discussed in chapter 5.

Anterior Stafne's bone cavity mimicking a periapical lesion of endodontic origin: report of two cases

INTRODUCTION: This report of 2 cases describes the diagnostic procedures used to identify 2 Stafne's bone cavities (SBC) found in unusually anterior locations in the mandible, both mimicking periapical lesions of endodontic origin. METHODS: In the first patient, a 47-year-old man, an SBC was diagnosed in the area of teeth #27, 28, and 29. In the second patient, a 62-year-old man, the SBC was a fortuitous finding, because this patient was referred for dental implant therapy. RESULTS: In both cases, the final diagnosis was achieved by using limited cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI). In both patients, the lingual bone cavity was found to be occupied by accessory salivary gland tissue. CONCLUSIONS: The combination of CBCT and MRI as noninvasive diagnostic techniques seems ideal to avoid surgical explorations, incisional biopsies, or enucleations of the lesion for diagnostic purposes.

Blood vessel anomalities in the oral cavity of two calves

Two calves were presented with a congenital mass in the rostral mandibular gingiva. In both cases the masses relapsed after surgical removal. Histologically, the two masses were composed of irregularly arranged vascular cavities, embedded in loosely arranged stroma and alcian-blue PAS positive ground substance. Radiologically, a destruction of the alveolar cavity was recognized in both cases, which was in case 1 histologically compatible with bone resorption and remodeling associated with the infiltration of abundant granulation tissue. A literature survey revealed that no consistent criteria for a correct classification for vascular tumours exists, resulting in the fact that comparable lesions were named differently in the past. We therefore propose to classify such lesions as congential vascular malformation until distinct morphological, immunohistochemical and molecular genetic analysis criteria will exist.

Harmonic Oscillator in a 1D or 2D Cavity with General Perfectly Reflecting Walls

We investigate the simple harmonic oscillator in a 1-d box, and the 2-d isotropic harmonic oscillator problem in a circular cavity with perfectly reflecting boundary conditions. The energy spectrum has been calculated as a function of the self-adjoint extension parameter. For sufficiently negative values of the self-adjoint extension parameter, there are bound states localized at the wall of the box or the cavity that resonate with the standard bound states of the simple harmonic oscillator or the isotropic oscillator. A free particle in a circular cavity has been studied for the sake of comparison. This work represents an application of the recent generalization of the Heisenberg uncertainty relation related to the theory of self-adjoint extensions in a finite volume.

Hormonal Contraceptive Use and the Prevalence of Endometriotic Lesions at Different Regions within the Peritoneal Cavity.

Endometriosis is an estrogen-dependent disease that can lead to chronic pain and subfertility. Endometriotic lesions found in different locations are heterogeneous and may represent a collection of related but distinct conditions. Whether there is a relationship between hormonal contraceptive (HC) use and endometriosis is still controversial. The purpose of this study was to determine whether HC use affected the prevalence of endometriotic lesions differently based on lesion location. Data was retrospectively collected from 161 patients presenting to the Berne University Women's Hospital between 2008 and 2012 for laparoscopic investigation. Women with histologically proven endometriosis were included in the study and patients were grouped according to lesion location and HC use. The results of the study indicate that HC users are significantly less likely to have endometriotic lesions on the ovaries, although in contrast, no difference was observed in the incidence of lesions in the rectovaginal septum (RVS) or peritoneal region. In addition, women using HC who were diagnosed with endometriotic lesions on the peritoneum were significantly younger than women with lesions in other locations. In conclusion, women with endometriosis who are currently using HC are less likely to have ovarian endometriotic lesions than in alternate locations.

Regression of the inflammatory microenvironment of the peritoneal cavity in women with endometriosis by GnRHa treatment.

OBJECTIVE To investigate the effect of gonadotropin-releasing hormone analogues (GnRHa) on the peritoneal fluid microenvironment in women with endometriosis. STUDY DESIGN Peritoneal fluid was collected from 85 women with severe endometriosis (rAFS stage III and IV) during laparoscopic surgery during the proliferative phase. Prior to surgery clinical data were collected. The concentrations of specific markers for endometriosis in the peritoneal fluid were determined using an ELISA and a comparison between peritoneal fluid markers in women using GnRHa and no hormonal treatment was performed using a non-parametric Mann-Whitney U test. RESULTS The study included peritoneal fluid from 39 patients who had been administered GnRHa (Zoladex(®)) in the three months prior to surgery and 46 from women with no hormonal treatment in this period. Concentrations of IL-8, PAPP-A, glycodelin-A and midkine were significantly reduced in the GnRHa treatment group compared to women receiving no hormonal treatment. RANTES, MCP-1, ENA-78, TNF-α, OPG, IP-10 and defensin showed no significant change between the two groups. CONCLUSIONS GnRHa mediate a significant regression in the inflammatory nature of the peritoneal microenvironment in women with endometriosis.

Fate of accidental symmetries of the relativistic hydrogen atom in a spherical cavity

The non-relativistic hydrogen atom enjoys an accidental SO(4) symmetry, that enlarges the rotational SO(3) symmetry, by extending the angular momentum algebra with the Runge–Lenz vector. In the relativistic hydrogen atom the accidental symmetry is partially lifted. Due to the Johnson–Lippmann operator, which commutes with the Dirac Hamiltonian, some degeneracy remains. When the non-relativistic hydrogen atom is put in a spherical cavity of radius R with perfectly reflecting Robin boundary conditions, characterized by a self-adjoint extension parameter γ, in general the accidental SO(4) symmetry is lifted. However, for R=(l+1)(l+2)a (where a is the Bohr radius and l is the orbital angular momentum) some degeneracy remains when γ=∞ or γ = 2/R. In the relativistic case, we consider the most general spherically and parity invariant boundary condition, which is characterized by a self-adjoint extension parameter. In this case, the remnant accidental symmetry is always lifted in a finite volume. We also investigate the accidental symmetry in the context of the Pauli equation, which sheds light on the proper non-relativistic treatment including spin. In that case, again some degeneracy remains for specific values of R and γ.

Kelvin-Helmholtz instabilities at the magnetic cavity boundary of comet 67P/Churyumov-Gerasimenko

We investigate the plasma environment of comet 67P/Churyumov-Gerasimenko, the target of the European Space Agency's Rosetta mission. Rosetta will rendezvous with the comet in 2014 at almost 3.5 AU and follow it all the way to and past perihelion at 1.3 AU. During its journey towards the inner solar system the comet's environment will significantly change. The interaction of the solar wind with a well developed neutral coma leads to the formation of an upstream bow shock and, closer to the comet, the inner shock separating the solar wind, with cometary pick-up ions mass-loaded, from the inner cometary ions which are dragged outward through abundant collisions and charge exchange with the expanding neutral gas. As a consequence the interplanetary magnetic field is prevented from penetrating the innermost region of the comet, the so-called magnetic cavity. We use our magnetohydrodynamics model BATSRUS (Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme) to simulate the solar wind - comet interaction. The model includes photoionization, ion-electron recombination, and charge exchange. Under certain conditions our model predicts an unstable plasma flow at the inner shock. We show that the plasma shear flow around the magnetic cavity can lead to Kelvin-Helmholtz instabilities. We investigate the onset of this phenomenon with change of heliocentric distance and furthermore show that a previously stable magnetic cavity boundary can become unstable when the neutral gas is predominately released from the dayside of the comet.

Recommendations from GEC ESTRO Breast Cancer Working Group (I): Target definition and target delineation for accelerated or boost Partial Breast Irradiation using multicatheter interstitial brachytherapy after breast conserving closed cavity surgery

OBJECTIVE The aim was to develop a delineation guideline for target definition for APBI or boost by consensus of the Breast Working Group of GEC-ESTRO. PROPOSED RECOMMENDATIONS Appropriate delineation of CTV (PTV) with low inter- and intra-observer variability in clinical practice is complex and needs various steps as: (1) Detailed knowledge of primary surgical procedure, of all details of pathology, as well as of preoperative imaging. (2) Definition of tumour localization before breast conserving surgery inside the breast and translation of this information in the postoperative CT imaging data set. (3) Calculation of the size of total safety margins. The size should be at least 2 cm. (4) Definition of the target. (5) Delineation of the target according to defined rules. CONCLUSION Providing guidelines based on the consensus of a group of experts should make it possible to achieve a reproducible and consistent definition of CTV (PTV) for Accelerated Partial Breast Irradiation (APBI) or boost irradiation after breast conserving closed cavity surgery, and helps to define it after selected cases of oncoplastic surgery.

Interobserver variations of target volume delineation in multicatheter partial breast brachytherapy after open cavity surgery

PURPOSE To investigate interobserver variations of target volume delineations in accelerated partial breast irradiation with multicatheter brachytherapy (BT) and to assess the impact of guidelines on consistency of contouring. METHODS AND MATERIALS A contouring study with two phases in interstitial accelerated partial breast irradiation after open cavity surgery was conducted by the Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology Breast Cancer Working Group. Contours of cavity and planning target volume (PTV) on preimplant and postimplant CT images were delineated. In Phase 1, nine radiation oncologists defined the target volumes of 5 patients, whereas in Phase 2, four observers draw the contours of 4 patients applying guidelines. In Phase 1, experience in breast BT after open cavity surgery was assessed. The delineations were compared between Phase 1 and Phase 2, the impact of guidelines was assessed, and cavity visualization score was related to consistency of delineations. RESULTS Significant interobserver variability in delineations of lumpectomy cavity and PTV was observed among the participants. Observers with BT experience after open cavity surgery outlined the cavity and PTV more consistently (conformity indexgen: 0.52 vs. 0.48 and 0.59 vs. 0.55 for preimplant and postimplant cavities). For all volumes, the mean Vmax/Vmin was 2.2 vs. 2.8. Having used guidelines all conformity indices increased significantly. For cavity, the increase was 14% and 11%, whereas for the PTV, 28% and 17% on the preimplant and postimplant CT images, respectively. A strong correlation was found between consistency of contours and cavity visualization score. CONCLUSIONS Simple guidelines on defining the lumpectomy cavity significantly increased the consistency of contouring. Reliable consistency of target volume definition can be expected only for good cavity visibility.