Detectors of scientific instruments on spacecraft flying through Jupiter radiation belts need to be protected from high fluxes of penetrating radiation by means of radiation shields. Electrons ...constitute the most difficult component of Jupiter's magnetosphere to shield from, because of their abundance, penetration depth in matter, and intensity of bremsstrahlung radiation generated upon interaction with the shielding material. For the Neutral and Ion Mass spectrometer (NIM) of the Particle Environment Package (PEP) instrument suite on board the European Space Agency's mission JUpiter Icy moons Explorer (JUICE), we devised a shielding design made of an aluminum and tantalum stack to reduce the radiation-induced noise on its Micro-Channel Plate (MCP) detector. To predict the expected radiation background in the mass spectra in space, we manufactured a flight-like shielded detector and submitted it to radiation testing at the Paul Scherrer Institut with an electron beam in the energy range ~ 30 to ~ 345 MeV. The results of this test provide a verification of the NIM capability to fulfill its science requirements in the mission's worst-case scenario (the Europa flyby), and give insights into new directions of optimization of shielding elements' design for NIM and similar instrument bound to operate in a harsh radiation environment.
Neutral Ion Mass spectrometer (NIM) is one of the instruments in the Particle Environmental Package (PEP) designed for the JUICE mission of ESA to the Jupiter system. NIM, equipped with a sensitive ...MCP ion detector, will conduct detailed measurements of the chemical composition of Jovian icy moons exospheres. To achieve high sensitivity of the instrument, radiation effects due to the high radiation background (high-energy electrons and protons) around Jupiter have to be minimised. We investigate the performance of an Al–Ta–Al composite stack as a potential shielding against high-energy electrons. Experiments were performed at the PiM1 beam line of the High Intensity Proton Accelerator Facilities located at the Paul Scherrer Institute, Villigen, Switzerland. The facility delivers a particle beam containing e−, μ− and π− with momentum from 17.5 to 345MeV/c (Hajdas et al., 2014). The measurements of the radiation environment generated during the interaction of primary particles with the Al–Ta–Al material were conducted with dedicated beam diagnostic methods and with the NIM MCP detector. In parallel, modelling studies using GEANT4 and GRAS suites were performed to identify products of the interaction and predict ultimate fluxes and particle rates at the MCP detector. Combination of experiment and modelling studies yields detailed characterisation of the radiation fields produced by the interaction of the incident e− with the shielding material in the range of the beam momentum from 17.5 to 345MeV/c. We derived the effective MCP detection efficiency to primary and secondary radiation and effective shielding transmission coefficients to incident high-energy electron beam in the range of applied beam momenta. This study shows that the applied shielding attenuates efficiently high-energy electrons. Nevertheless, owing to nearly linear increase of the bremsstrahlung production rate with incident beam energy, above 130MeV their detection rates measured by the MCP detector compares to the MCP rate of the incident electron beam. We define key performance parameters for the shielding and show direction of its improvements by introducing additional layer of material to attenuate γ-rays and reduce the MCP sensitivity to the penetrating radiation. The experiments also verify the predictions by modelling tools used currently for optimisation of shielding against high-energy particles.
Radium 223 dichloride (Ra223) is the only targeted alpha therapy able to extend survival in patients with bone metastases from prostate cancer. Mechanism of action and data currently available ...focused mainly on osteoblastic metastases from prostate cancer. Phase 1 and 2 trials documented a clinical efficacy also in breast cancer patients with predominately bone disease, highlighting a reduction in alkaline phosphatase and other bone biomarkers. In our institution, a patient with breast cancer affected by osteolytic metastases was treated with off-label use of Ra223. Our patient had a good treatment compliance and up to now she has not been revealed the presence of SSE or hematological complications. Our preliminary experience shows that Ra223 may play a critical role to bone metastates in patients with breast cancer.
A reconfigurable microstrip dipole antenna solution for multiple-input multiple-output (MIMO) communication systems making use of orthogonal frequency division multiplexing (OFDM) is presented. When ...applied to closely spaced antenna arrays, this method can increase link capacity. The benefits of this novel antenna solution are demonstrated by channel capacity measurements taken in an indoor environment with a 2*2 MIMO system.
•Anionic beta cyclodextrin retains drug into the layer-by-layer system•Anionic beta cyclodextrin controls drug release from the layer-by-layer system•The effective drug delivery system is readily ...tunable to different physiological scenarios•The drug delivery system shows antibacterial effect against Staphylococcus aureus•An extended effect in bacteria reducing on coating was maintained up to 30 days
This study demonstrated a drug-delivery system with anionic beta cyclodextrin (β-CD) complexes to retain tetracycline (TC) and control its release from multilayers of poly(acrylic acid) (PAA) and poly(l-lysine) (PLL) in a ten double layers (PAA/PLL10) coating onto titanium. The drug-delivery capacity of the multilayer system was proven by controlled drug release over 15 days and sustained released over 30 days. Qualitative images confirmed TC retention within the layer-by-layer (LbL) over 30 days of incubation. Antibacterial activity of TC/anionic β-CD released from the LbL was established against Staphylococcus aureus species. Remarkably, PAA/PLL10/TC/anionic β-CD antibacterial effect was sustained even after 30 days of incubation. The non-cytotoxic effect of the multilayer system revealed normal human gingival fibroblast growth. It is expected that this novel approach and the chemical concept to improve drug incorporation into the multilayer system will open up possibilities to make the drug release system more applicable to implantable percutaneous devices.
Pb(Zr,Ti)O
3
ceramics with homogenous, anisotropic porosity were manufactured and the influence of the anisotropic porosity on the dielectric and piezoelectric properties was studied. Image analysis ...allowed the quantification of the preferential orientation and the calculation of the distribution of the aspect ratio of the pores. The different dependence of the permittivities
and
on the porosity content demonstrates that the population of pores is constituted of a high volume of pores with low aspect ratio and a low volume of pores with high aspect ratio. In view of the quantitative results obtained on the microstructure, an explanation of the frequency dependence of the dielectric and piezoelectric behaviour is suggested. Furthermore, the higher d
31
piezoelectric coefficient in the material with anisotropic pores than in material with isotropic pores is related to higher effective fields which are a consequence of the enhanced longitudinal mobility of the material under transverse stress.
The internationally adopted child is a fragile subject who often shows an incomplete health documentation, which hinders the complete assessment of health status.
Between January 2010 and June 2016, ...at the University Hospital "AOUP P. Giaccone" of Palermo, we reviewed the health documentations of 111 children recently arrived in Italy following the conclusion of the international adoption procedure. 62.2% of the children were male, of various nationalities and with an average age of 7 years (± 3.4). This study aims to detect, in the observed sample, the reliability of the vaccinal documentation and the real acquired immunization. We intend to estimate the presence of IgG against Measles, Mumps, Rubella and Hepatitis B viruses.
Percentages of subjects with a complete correspondence between documentation attesting the successful vaccination and the effective immunization were: 78% for measles, 66% for mumps, 84% for rubella, 71% for hepatitis B. Percentages of subjects without vaccinal documentation but with positive evidence of IgG were: 50% for measles, 38% for mumps, 71% for rubella, 50% for hepatitis B.
The partial correspondence found between vaccinations performed and real immune status can be attributed to several reasons: poor reliability of the received health documentation, the complex economic situation of the health services in the countries of origin, the incorrect vaccines storage or the administration beyond the expiration date, the poor immunological response due to concomitant diseases or severe malnutrition, the probable non-administration of the expected booster dose. Particular attention needs to be paid to this population, which may represent a risk group susceptible to vaccine-preventable diseases.
This paper demonstrates a method that allows reconfigurable multi element antennas to select the antenna configuration at the receiver of a Multiple Input Multiple Output (MIMO) communication system. ...This antenna configuration selection scheme consists of using spatial correlation and average Signal to Noise Ratio (SNR) information to select the antenna radiation pattern at the receiver. We show that using this approach it is possible to achieve capacity gains in a multi element reconfigurable antenna system without modifying the data frame of a conventional MIMO system. We demonstrate our configuration selection algorithm through an analysis of reconfigurable circular patch antennas in realistic MIMO clustered channel models. Using this approach we also show that the functionality of the proposed selection scheme is connected to antenna parameters such as radiation efficiency, input impedance, the level of diversity between the radiation patterns of different antenna configurations, and the average system SNR. The capacity gain achievable with this configuration selection approach is calculated through numerical simulations using reconfigurable circular patch antennas at the receiver of a MIMO system that employs minimum mean square error receivers for channel estimation. The performance of the proposed method is compared to that of a MIMO system that estimates the channel transfer matrix for each antenna configuration in order to select the optimal receiver antenna radiation pattern. Channel capacity and Bit Error Rate (BER) results show the improvement offered by the proposed selection scheme relative to a conventional antenna selection technique for reconfigurable MIMO systems; in particular we show that the improvement increases with the number of configurations in the multi element reconfigurable antenna.
Aim Laparoscopic adhesiolysis has been demonstrated to be technically feasible in small bowel obstruction and carries advantages in terms of post‐surgical course. The increasing dissemination of ...laparoscopic surgery in the emergency setting and the lack of concrete evidence in the literature have called for a consensus conference to draw recommendations for clinical practice.
Methods A literature search was used to outline the evidence, and a consensus conference was held between experts in the field. A survey of international experts added expertise to the debate. A public jury of surgeons discussed and validated the statements, and the entire process was reviewed by three external experts.
Results Recommendations concern the diagnostic evaluation, the timing of the operation, the selection of patients, the induction of the pneumoperitoneum, the removal of the cause of obstructions, the criteria for conversion, the use of adhesion‐preventing agents, the need for high‐technology dissection instruments and behaviour in the case of misdiagnosed hernia or the need for bowel resection.
Conclusion Evidence of this kind of surgery is scanty because of the absence of randomized controlled trials. Nevertheless laparoscopic skills in emergency are widespread. The recommendations given with the consensus process might be a useful tool in the hands of surgeons.
We present a study of an impacting descent probe that increases the science return of spacecraft orbiting or passing an atmosphere-less planetary bodies of the solar system, such as the Galilean ...moons of Jupiter. The descent probe is a carry-on small spacecraft (<100 kg), to be deployed by the mother spacecraft, that brings itself onto a collisional trajectory with the targeted planetary body in a simple manner. A possible science payload includes instruments for surface imaging, characterisation of the neutral exosphere, and magnetic field and plasma measurement near the target body down to very low-altitudes (~1 km), during the probe’s fast (~km/s) descent to the surface until impact. The science goals and the concept of operation are discussed with particular reference to Europa, including options for flying through water plumes and after-impact retrieval of very-low altitude science data. All in all, it is demonstrated how the descent probe has the potential to provide a high science return to a mission at a low extra level of complexity, engineering effort, and risk. This study builds upon earlier studies for a Callisto Descent Probe for the former Europa-Jupiter System Mission of ESA and NASA, and extends them with a detailed assessment of a descent probe designed to be an additional science payload for the NASA Europa Mission.
PDF