Model of the Radio Frequency (RF) Excitation Response from Monopole and Dipole Antennas in a Large Scale Tank

Good antenna-mode coupling is needed for determining the amount of propellant in a tank through the method of radio frequency mass gauging (RFMG). The antenna configuration and position in a tank are important factors in coupling the antenna to the natural electromagnetic modes. In this study, different monopole and dipole antenna mounting configurations and positions were modeled and responses simulated in a full-scale tank model with the transient solver of CST Microwave Studio (CST Computer Simulation Technology of America, Inc.). The study was undertaken to qualitatively understand the effect of antenna design and placement within a tank on the resulting radio frequency (RF) tank spectrum

Diffuse Bauchschmerzen und Eosinophilie

Zusammenfassung: Die eosinophile Gastroenteritis ist eine relativ seltene Erkrankung unklarer Ätiologie mit einem heterogenen Krankheitsbild. Wichtige Differenzialdiagnosen stellen intestinale parasitäre Infektionen, das hypereosinophile Syndrom, Lymphome und andere maligne und allergische Erkrankungen dar. Die Diagnose kann meist mittels Anamnese und Standardlabor, zusammen mit den Ergebnissen von Biopsien oder Parazentese gestellt werden. Milde Formen mit lediglich Diarrhö als klinischer Manifestation können symptombezogen behandelt werden. Die Therapie bei schwereren Verläufen erfolgt initial mit Kortikosteroide

Radio Frequency Mass Gauging of Propellants

A combined experimental and computer simulation effort was conducted to measure radio frequency (RF) tank resonance modes in a dewar partially filled with liquid oxygen, and compare the measurements with numerical simulations. The goal of the effort was to demonstrate that computer simulations of a tank's electromagnetic eigenmodes can be used to accurately predict ground-based measurements, thereby providing a computational tool for predicting tank modes in a low-gravity environment. Matching the measured resonant frequencies of several tank modes with computer simulations can be used to gauge the amount of liquid in a tank, thus providing a possible method to gauge cryogenic propellant tanks in low-gravity. Using a handheld RF spectrum analyzer and a small antenna in a 46 liter capacity dewar for experimental measurements, we have verified that the four lowest transverse magnetic eigenmodes can be accurately predicted as a function of liquid oxygen fill level using computer simulations. The input to the computer simulations consisted of tank dimensions, and the dielectric constant of the fluid. Without using any adjustable parameters, the calculated and measured frequencies agree such that the liquid oxygen fill level was gauged to within 2 percent full scale uncertainty. These results demonstrate the utility of using electromagnetic simulations to form the basis of an RF mass gauging technology with the power to simulate tank resonance frequencies from arbitrary fluid configurations

Radio-Frequency Tank Eigenmode Sensor for Propellant Quantity Gauging

Although there are several methods for determining liquid level in a tank, there are no proven methods to quickly gauge the amount of propellant in a tank while it is in low gravity or under low-settling thrust conditions where propellant sloshing is an issue. Having the ability to quickly and accurately gauge propellant tanks in low-gravity is an enabling technology that would allow a spacecraft crew or mission control to always know the amount of propellant onboard, thus increasing the chances for a successful mission. The Radio Frequency Mass Gauge (RFMG) technique measures the electromagnetic eigenmodes, or natural resonant frequencies, of a tank containing a dielectric fluid. The essential hardware components consist of an RF network analyzer that measures the reflected power from an antenna probe mounted internal to the tank. At a resonant frequency, there is a drop in the reflected power, and these inverted peaks in the reflected power spectrum are identified as the tank eigenmode frequencies using a peak-detection software algorithm. This information is passed to a pattern-matching algorithm, which compares the measured eigenmode frequencies with a database of simulated eigenmode frequencies at various fill levels. A best match between the simulated and measured frequency values occurs at some fill level, which is then reported as the gauged fill level. The database of simulated eigenmode frequencies is created by using RF simulation software to calculate the tank eigenmodes at various fill levels. The input to the simulations consists of a fairly high-fidelity tank model with proper dimensions and including internal tank hardware, the dielectric properties of the fluid, and a defined liquid/vapor interface. Because of small discrepancies between the model and actual hardware, the measured empty tank spectra and simulations are used to create a set of correction factors for each mode (typically in the range of 0.999 1.001), which effectively accounts for the small discrepancies. These correction factors are multiplied to the modes at all fill levels. By comparing several measured modes with the simulations, it is possible to accurately gauge the amount of propellant in the tank. An advantage of the RFMG approach of applying computer simulations and a pattern-matching algorithm is that the Although there are several methods for determining liquid level in a tank, there are no proven methods to quickly gauge the amount of propellant in a tank while it is in low gravity or under low-settling thrust conditions where propellant sloshing is an issue. Having the ability to quickly and accurately gauge propellant tanks in low-gravity is an enabling technology that would allow a spacecraft crew or mission control to always know the amount of propellant onboard, thus increasing the chances for a successful mission. The Radio Frequency Mass Gauge (RFMG) technique measures the electromagnetic eigenmodes, or natural resonant frequencies, of a tank containing a dielectric fluid. The essential hardware components consist of an RF network analyzer that measures the reflected power from an antenna probe mounted internal to the tank. At a resonant frequency, there is a drop in the reflected power, and these inverted peaks in the reflected power spectrum are identified as the tank eigenmode frequencies using a peak-detection software algorithm. This information is passed to a pattern-matching algorithm, which compares the measured eigenmode frequencies with a database of simulated eigenmode frequencies at various fill levels. A best match between the simulated and measured frequency values occurs at some fill level, which is then reported as the gauged fill level. The database of simulated eigenmode frequencies is created by using RF simulation software to calculate the tank eigenmodes at various fill levels. The input to the simulations consists of a fairly high-fidelity tank model with proper dimensions and including internal tank harare, the dielectric properties of the fluid, and a defined liquid/vapor interface. Because of small discrepancies between the model and actual hardware, the measured empty tank spectra and simulations are used to create a set of correction factors for each mode (typically in the range of 0.999 1.001), which effectively accounts for the small discrepancies. These correction factors are multiplied to the modes at all fill levels. By comparing several measured modes with the simulations, it is possible to accurately gauge the amount of propellant in the tank. An advantage of the RFMG approach of applying computer simulations and a pattern-matching algorithm is that th

Bone mineral as a drug-seeking moiety and a waste dump

Bone is a dynamic tissue with a quarter of the trabecular and a fifth of the cortical bone being replaced continuously each year in a complex process that continues throughout an individual’s lifetime. Bone has an important role in homeostasis of minerals with non-stoichiometric hydroxyapatite bone mineral forming the inorganic phase of bone. Due to its crystal structure and chemistry, hydroxyapatite (HA) and related apatites have a remarkable ability to bind molecules. This review article describes the accretion of trace elements in bone mineral giving a historical perspective. Implanted HA particles of synthetic origin have proved to be an efficient recruiting moiety for systemically circulating drugs which can locally biomodulate the material and lead to a therapeutic effect. Bone mineral and apatite however also act as a waste dump for trace elements and drugs, which significantly affects the environment and human health

Alterations in vascular function in primary aldosteronism - a cardiovascular magnetic resonance imaging study

Introduction: Excess aldosterone is associated with increased cardiovascular risk. Aldosterone has a permissive effect on vascular fibrosis. Cardiovascular magnetic resonance imaging (CMR) allows study of vascular function by measuring aortic distensibility. We compared aortic distensibility in primary aldosteronism (PA), essential hypertension (EH) and normal controls and explored the relationship between aortic distensibility and pulse wave velocity (PWV).<p></p> Methods: We studied PA (n=14) and EH (n=33) subjects and age-matched healthy controls (n=17) with CMR, including measurement of aortic distensibility, and measured PWV using applanation tonometry. At recruitment, PA and EH patients had similar blood pressure and left ventricular mass.<p></p> Results: Subjects with PA had significantly lower aortic distensibilty and higher PWV compared to EH and healthy controls. These changes were independent of other factors associated with reduced aortic distensibility, including aging. There was a significant relationship between increasing aortic stiffness and age in keeping with physical and vascular aging. As expected, aortic distensibility and PWV were closely correlated.<p></p> Conclusion: These results demonstrate that PA patients display increased arterial stiffness compared to EH, independent of vascular aging. The implication is that aldosterone invokes functional impairment of arterial function. The long-term implications of arterial stiffening in aldosterone excess require further study.<p></p&gt

Outcome and Predictors of Treatment Failure in Total Hip/Knee Prosthetic Joint Infections Due to Staphylococcus aureus

The results of the present study suggest that ASA score ≤ 2 and use of rifampin-combination therapy are two independent factors associated with favorable outcome of patients treated for total hip or knee prosthetic infections due to S. aureus

Treatment of knee prosthesis infections: evaluation of 15 patients over a 5-year period

Our objective was to evaluate different treatment alternatives for total knee arthroplasty (TKA) infection and to compare outcomes depending on adherence to a current treatment algorithm. All patients treated for a first episode of TKA infection between January 2000 and July 2005 were included. Patient records were reviewed and data were extracted retrospectively. Fifteen patients were followed up for a median of 25 months. The cure rate in patients with two-stage exchange of knee prosthesis was higher than in patients who had débridement without implant removal (100 vs 37%, p = 0.03). Cure rates were not different between these two surgical approaches in ten patients who were treated according to a current treatment algorithm. Success rates for treatment of TKA infections varied considerably with the treatment strategy chosen. Our results support the use of existing algorithms to select patients who are eligible for débridement with retention of the prosthesis or need two-stage exchange of knee implants

Single and double qubit gates by manipulating degeneracy

A novel mechanism is proposed for single and double qubit state manipulations in quantum computation with four-fold degenerate energy levels. The principle is based on starting with a four fold degeneracy, lifting it stepwise adiabatically by a set of control parameters and performing the quantum gate operations on non-degenerate states. A particular realization of the proposed mechanism is suggested by using inductively coupled rf-squid loops in the macroscopic quantum tunnelling regime where the energy eigen levels are directly connected with the measurable flux states. The one qubit and two qubit controlled operations are demonstrated explicitly. The appearance of the flux states also allows precise read-in and read-out operations by the measurement of flux.Comment: 6 pages + 5 figures (separately included

Dephasing of coupled spin qubit system during gate operations due to background charge fluctuations

It has been proposed that a quantum computer can be constructed based on electron spins in quantum dots or based on a superconducting nanocircuit. During two-qubit operations, the fluctuation of the coupling parameters is a critical factor. One source of such fluctuation is the stirring of the background charges. We focused on the influence of this fluctuation on a coupled spin qubit system. The induced fluctuation in exchange coupling changes the amount of entanglement, fidelity, and purity. In our previous study, the background charge fluctuations were found to be an important channel of dephasing for a single Josephson qubit.Comment: 10 pages, 7 figure. to be publishe