Comparison between measurement and calculations for a 14 MeV neutron water activation experiment

The nuclear heat loads due to gamma rays emitted from the decay of 16N and delayed neutrons from17N, generated by the activation of water in cooling circuits, are critical for ITER design. The assessment of nuclear heating from activated water is complex; it requires temporal and spatial dependent transport and activation calculations taking into account variation of irradiation, water flow conditions and cooling circuits’ parameters. A water activation experiment has been recently conducted at the14 MeV Frascati Neutron Generator (FNG) in order to validate the methodology for water activation assessment used for ITER and to reduce the safety factors applied to the calculation results, which have a large impact on the schedule, commissioning and licensing. Water circulating inside an ITER First Wall (FW) mock-up was irradiated with 14 MeV neutrons and then measured using a large CsI scintillator detector. The system consists of a closed water loop where the cooling water, transiting through an ITER FW mock-up, is irradiated by FNG. The induced 16N activity via 14 MeV neutrons interactions with 16O via the 16O(n,p)16N reaction is measured in a dedicated counting station via an expansion volume. The water then passes to a much larger holding delay tank, and after several 16N half-lives decay time, it is then recirculated and exposed again to neutrons in the ITER First Wall (FW) mock-up. The measured 16N activity is obtained measuring the emitted characteristic 6.13 and 7.12 MeV gamma-rays. Calculations were performed in an accurate model of the FW mock-up using the MCNP Monte Carlo code and FENDL-3.1 nuclear data library to obtain the predicted flux impinging on the water. The EASY-2007 inventory code was used to predict the 16N activity. In this work, a comparison between measurements and calculations is reported together with associated uncertainty analysis.

Methodology of the Experiments to Study Lithium CPS Interaction with Deuterium Under Conditions of Reactor Irradiation

Problems of plasma-facing materials degradation and in-vessel element destructions, tritium accumulation and plasma pollution can be overcome by the use of liquid metals with low atomic number. The best candidate as a material for divertor receiving plates and other in-vessel devices is lithium. One of the problems associated with the use of such lithium systems in the fusion reactors is to determine the parameters of the working gases interaction with plasma facing surfaces under conditions simulating real operation, i.e. under conditions of neutron and gamma radiation. This paper describes a technique of the reactor experiments to study lithium capillary-porous systems (CPS) interaction with deuterium under neutron irradiation. The neutron-physical and thermophysical calculations were the basis for the design development and further manufacture of a unique irradiation ampoule device with a lithium CPS sample. Several experiments were performed to calibrate the deuterium fluxes through experimental cell with lithium CPS; and preliminary results of these experiments were obtained.

TWO NEW SINGLE-EXPOSURE, MULTI-DETECTOR NEUTRON SPECTROMETERS FOR RADIATION PROTECTION APPLICATIONS IN WORKPLACE MONITORING

This communication describes two new instruments, based on multiple active thermal neutron detectors arranged within a single moderator, that permit to unfold the neutron spectrum (from thermal to hundreds of MeV) and to determine the corresponding integral quantities with only one exposure. This makes them especially advantageous for neutron field characterisation and workplace monitoring in neutron-producing facilities. One of the devices has spherical geometry and nearly isotropic response, the other one has cylindrical symmetry and it is only sensitive to neutrons incident along the cylinder axis. In both cases, active detectors have been specifically developed looking for the criteria of miniaturisation, high sensitivity, linear response and good photon rejection. The calculated response matrix has been validated by experimental irradiations in neutron reference fields with a global uncertainty of 3%. The measurements performed in realistic neutron fields permitted to determine the neutron spectra and the integral quantities, in particular H*(10).

Antibiotic-loaded bone cement reduces risk of infections in primary total knee arthroplasty? A systematic review

PURPOSE

Antibiotic-loaded bone cement has been widely used for the treatment of infected knee replacement, but its routine use in primary TKA remains controversial. The aim of this systematic review was to analyze the literature about the antimicrobial efficacy and safety of antibiotic-loaded bone cement for its prophylactic use in primary TKA.

METHODS

A detailed and systematic search of the Pubmed, Medline, Cochrane Reviews and Google Scholar databases had been performed using the keyword "total knee arthroplasty" "total knee replacement" "total knee prosthesis" and "antibiotic-loaded bone cement" with no limit regarding the year of publication. We used modified Coleman scoring methodology (mCMS) to identify scientifically sound articles in a reproducible format. The review was limited to the English-language articles.

RESULTS

Six articles met inclusion criteria. In total, 6318 arthroplasties were included in our study. 3217 of these arthroplasties received antibiotic-loaded bone cement and 3101 arthroplasties served as the control. There was no statistical difference between the two groups in terms of the incidence of deep or superficial surgical site infection. The average mCMS score was 67.6, indicating good methodological quality in the included studies.

CONCLUSIONS

Present review did not reveal any significant difference in terms of rate of deep or superficial surgical site infection in patients receiving antibiotic-loaded bone cement compared with the control (plain bone cement) during primary TKA. The clinical relevance of this study was that the use of antibiotic-loaded bone cement did not significantly reduce the risk of infection in primary TKA.

LEVEL OF EVIDENCE

III.

A SINGLE-EXPOSURE, MULTIDETECTOR NEUTRON SPECTROMETER FOR WORKPLACE MONITORING

This communication describes a recently developed single-exposure neutron spectrometer, based on multiple active thermal neutron detectors located within a moderating sphere, which have been developed jointly by CIEMAT (Spain), INFN (Italy) and Politecnico di Milano (Italy) in the framework of Italian and Spanish collaboration projects. The fabricated prototypes permit to achieve spectrometric resolution with nearly isotropic response for neutron with energies from thermal to 100-200 MeV, thus being able to characterise the complete neutron spectrum in only one exposure by unfolding the measured responses of the detectors. This makes it especially advantageous for characterising neutron fields and workplace monitoring purposes in neutron-producing facilities.

The risk for type B aortic dissection in Marfan syndrome

Marfan syndrome is the most prevalent connective tissue disorder, with an autosomal dominant inheritance with variable penetrance. This paper aims to summarize epidemiology and treatment for type B dissection in Marfan patients.

Endovascular treatment of popliteal aneurysm

Although traditional surgical repair by aneurysm exclusion and bypass is still considered the gold standard in the treatment of popliteal artery aneurysms (PAAs), the endovascular repair (ER) has been gaining great interest in the last decades. ER offers several advantages over open bypass, including lower morbidity and mortality, and faster functional recovery, but some concerns about migration, occlusion, or fracture remain when a stent graft is deployed across a joint that undergo constant flexion. This review summarizes the current evidence on ER for PAAs. Level I evidence is still very limited, while the majority of published data come from retrospective studies. Moreover the heterogeneity of PAA morphology seems to play a major role in the outcomes after popliteal endografts placement, so that many anatomical criteria should be taken into account to determine which patient is best treated endovascularly. In conclusion, while it is unlike that endovascular treatment may displace open surgical bypass in the near future, it indeed does provide a feasible option for selected patients with high surgical risk and good anatomical features.

Prosthesis infection: prevention and treatment

Implantation of a vascular prosthesis increases surgical site infection risk by producing a microenvironment conducive to bacterial attachment and biofilm formation, which sustains bacterial colonization and protects encased organisms from host defenses and antimicrobial therapy. Many maneuvers are used in an attempt to reduce infection in arterial reconstructions, but there are no clear guidelines on the most appropriate or effective. As well, there is no good evidence to guide management. A general principle is that indication for removal of the entire infected graft is mandatory when a suture line is involved in the infectious process, an infected anastomotic aneurism and a suture-line hemorrhage is evident, or when a graft-enteric fistula is diagnosed. Conservative, non-resectional management of graft infection is still a respectable solution for selected patients, as those with significant comorbidities, or those where the implanted aortic graft is in a location that precludes excision without causing a high likelihood of morbidity and/or mortality. Anyway, definitive management depends on the patient's condition and a tailored approach should be always offered. Surgical techniques favor in terms of mortality, patency and reinfection rate the in situ reconstruction. Currently, the choice of the technique used relies on center and operator's experience. This article summarizes the incidence of graft infection, analyze the predisponding factors to graft infection, and review current strategies for prevention and treatment of prosthesis and endograft infection.

Development of single-exposure, multidetector neutron spectrometers: the NESCOFI@BTF project

NESCOFI@BTF is a 3-y project (2011-13) supported by the Scientific Commission 5 of INFN (Italy). The target is the development of neutron spectrometers similar to the Bonner spheres, in terms of response energy interval and accuracy, but able to determine the neutron spectrum in only one exposure. These devices embed multiple (10 to 30) thermal neutron detectors (TNDs) within a single moderator. Two prototypes, called SPherical SPectrometer (SP(2)) and cylindrical spectrometer (CYSP), have been set up. Whilst SP(2) has spherical geometry and nearly isotropic response, the CYSP has cylindrical geometry and is intended to be used as a directional spectrometer. Suitable active TNDs will be embedded in the final version of the devices. The resulting instruments could be used as real-time neutron spectrometers in neutron-producing facilities. This communication describes the design criteria, numerical analysis, experimental issues, state-of-the-art and future developments connected with the development of these instruments.

The role of hybrid procedures in the treatment of critical limb ischemia

Patients affected by critical limb ischemia (CLI) represent a complex and high risk clinical problem, and a multidisciplinary approach is often demanded. The amputation rate in patients affected by CLI is still high. Introduction of endovascular procedure shook up the CLI concept of treatment. The increasing experience of Vascular Surgeons in endovascular technique forced these specialist to match classic surgical skills and endovascular tools in order to achieve the best treatment for each patients. The combination of the two techniques identifies the hybrid procedure. Aim of this paper is to define indication, necessity and results of the hybrid procedure in patients suffering from CLI.

Endovascular first as "preliminary approach" for critical limb ischemia and diabetic foot

The treatment of the critical limb ischemia (CLI) and diabetic foot (DB) is still object of discussion and the gold standard for revascularization has not yet been identified. In these two decades the introduction of endovascular procedures had a large impact on the surgical revascularization and were added to the practice of vascular surgeons in patients who cannot be candidates for a bypass. This may be due to significant comorbidities, a reduced life expectancy, infection or gangrene in the possible sites of distal anastomoses, the unavailability of suitable veins, or the absence of an adequate "landing zone" for the distal part of the bypass. Various studies have evaluated the role of PTA in DF and CLI that resulted favourable in terms of feasibility, technical efficacy, the reduced number of complications, and limb salvage rates. Anyway, long-term patency is better after bypass surgery than after angioplasty, which is burdened by a high restenosis rate. In our experience we tried to practice endovascular approach as a first choice. If the procedure cannot be concluded safely, we continue the intervention surgically or use a hybrid approach. The endovascular-first strategy seems to be the future regardless of comorbidity of the patient and the degree of pathology. The vascular surgeon remains the only specialist that can decide the correct intervention without pressure or been forced and, last but not least, the only one who can independently perform hybrid interventions.

Test of "crab-waist" collisions at the DAPhiNE Phi factory

The electron-positron collider DAPhiNE, the Italian Phi factory, has been recently upgraded in order to implement an innovative collision scheme based on large crossing angle, small beam sizes at the crossing point, and compensation of beam-beam interaction by means of sextupole pairs creating a "crab-waist" configuration in the interaction region. Experimental tests of the novel scheme exhibited an increase by a factor of 3 in the peak luminosity of the collider with respect to the performances reached before the upgrade. In this Letter we present the new collision scheme, discuss its advantages, describe the hardware modifications realized for the upgrade, and report the results of the experimental tests carried out during commissioning of the machine in the new configuration and standard operation for the users.

Observations of the vacuum ultraviolet and x-ray brightness profiles of Fe, Ni, and Ge in magnetically confined fusion plasmas

The spatial brightness profiles of emission lines for the K-like through He-like ionization states of Fe, Ge, and Ni have been measured during a set of experiments in which Fe and Ge were introduced into FTU tokamak plasmas by using the laser blowoff technique. Nickel was an intrinsic impurity observed during these experiments that was sputtered from the inconel limiter. The brightness profiles were measured by spatially scanable, photometrically calibrated vaccum ultraviolet and x-ray spectrometers that covered the 1 to 1700 A region. Simulations of these profiles and the time evolution of the laser blowoffs were performed with the MIST transport code using several sets of atomic physics compilations [ADPAK (originally in MIST), Arnaud and Raymond (AR92), Arnaud and Rothenflug (AR85), Mazzotta et al., and Mattioli (an extension to Mazzotta)]. The goal was to determine which set of available rates could best simulate the measured spatial brightness profiles and the charge state balance in the plasma. The Mazzotta et al. (for Fe and Ni), the Mattioli (for Ge), and the AR92 (for Fe only) rates adequately simulated the He-, Li-, Be-, Na-, Mg-like ionization states. The F- to B-like charge states could not be simulated by these compilations unless the relevant dielectronic rates were multiplied by a factor of 2. The ADPAK rates could not adequately predict any of the charge states of Fe, Ge, or Ni.

Cosmic rays observed by the resonant gravitational wave detector NAUTILUS

The passage of cosmic rays has been observed to excite mechanical vibrations in the resonant gravitational wave detector NAUTILUS operating at temperature of 100 mK. A very significant correlation (more than 10 standard deviations) is found.