This paper presents the first plasmid DNA irradiations carried out with Very High Energy Electrons (VHEE) over 100-200 MeV at the CLEAR user facility at CERN to determine the Relative Biological ...Effectiveness (RBE) of VHEE. DNA damage yields were measured in dry and aqueous environments to determine that ~ 99% of total DNA breaks were caused by indirect effects, consistent with other published measurements for protons and photons. Double-Strand Break (DSB) yield was used as the biological endpoint for RBE calculation, with values found to be consistent with established radiotherapy modalities. Similarities in physical damage between VHEE and conventional modalities gives confidence that biological effects of VHEE will also be similar-key for clinical implementation. Damage yields were used as a baseline for track structure simulations of VHEE plasmid irradiation using GEANT4-DNA. Current models for DSB yield have shown reasonable agreement with experimental values. The growing interest in FLASH radiotherapy motivated a study into DSB yield variation with dose rate following VHEE irradiation. No significant variations were observed between conventional and FLASH dose rate irradiations, indicating that no FLASH effect is seen under these conditions.
It is unknown whether COVID-19 patients are at higher risk due to demographic and clinical characteristics associated with higher COVID-19 infection risk and severity of infection, or due to the ...disease and its management.
To assess the impact of COVID-19 on healthcare-associated infection (HAI) transmission and antimicrobial use (AMU) prevalence during the later stages of the pandemic.
A point-prevalence survey (PPS) was conducted among 325 acute care hospitals of 19 out of 21 Regions of Italy, during November 2022. Non-COVID-19 patients were matched to COVID-19 patients according to age, sex, and severity of underlying conditions. HAI and AMU prevalence were calculated as the percentage of patients with at least one HAI or prescribed at least one antimicrobial over all included patients, respectively.
In total, 60,403 patients were included, 1897 (3.14%) of which were classified as COVID-19 patients. Crude HAI prevalence was significantly higher among COVID-19 patients compared to non-COVID-19 patients (9.54% vs 8.01%; prevalence rate ratio (PRR): 1.19; 95% confidence interval (CI): 1.04–1.38; P < 0.05), and remained higher in the matched sample; however, statistical significance was not maintained (odds ratio (OR): 1.25; 95% CI: 0.99–1.59; P = 0.067). AMU prevalence was significantly higher among COVID-19 patients prior to matching (46.39% vs 41.52%; PRR: 1.21; 95% CI: 1.11–1.32; P < 0.001), and significantly lower after matching (OR: 0.77; 95% CI: 0.66–0.89; P < 0.001).
COVID-19 patients could be at higher HAI risk due to underlying clinical conditions and the intensity of healthcare needs. Further efforts should be dedicated to antimicrobial stewardship among COVID-19 patients.
Currently, there is great clinical need for suitable synthetic grafts that can be used in vascular diseases. Synthetic grafts have been successfully used in medium and large arteries, however, their ...use in small diameter vessels is limited and presents a high failure rate. In this context, the aim of this study was to develop tissue engineering scaffolds, using poly(trimethylene carbonate-co-L-lactide) (PTMCLLA), for application as small diameter vascular grafts. For this, copolymers with varying trimethylene carbonate/lactide ratios - 20/80, 30/70, and 40/60 - were submitted to electrospinning and the resulting scaffolds were evaluated in terms of their physicochemical and biological properties. The scaffolds produced with PTMCLLA 20/80, 30/70, and 40/60 showed smooth fibers with an average diameter of 771±273, 606±242, and 697±232 nm, respectively. When the degradation ratio was evaluated, the three scaffold groups had a similar molecular weight (Mw) on the final day of analysis. PTMCLLA 30/70 and 40/60 scaffolds exhibited greater flexibility than the PTMCLLA 20/80. However, the PTMCLLA 40/60 scaffolds showed a large wrinkling and their biological properties were not evaluated. The PTMCLLA 30/70 scaffolds supported the adhesion and growth of mesenchymal stem cells (MSCs), endothelial progenitor cells, and smooth muscle cells (SMCs). In addition, they provided a spreading of MSCs and SMCs. Given the results, the electrospun scaffolds produced with PTMCLLA 30/70 copolymer can be considered promising candidates for future applications in vascular tissue engineering.
The CLEAR user facility at CERN Gamba, D.; Corsini, R.; Curt, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2018, Letnik:
909
Journal Article
Recenzirano
Odprti dostop
The conversion of the CALIFES beamline of CTF3 into the “CERN Linear Electron Accelerator for Research” (CLEAR) facility was approved in December 2016. The primary focus for CLEAR is general ...accelerator R&D and component studies for existing and possible future accelerator applications. This includes studies for high gradient acceleration methods, e.g. for CLIC and plasma technology, and prototyping and validation of accelerator components, e.g. for the HL-LHC upgrade. The facility also provides irradiation test capabilities for characterisation of electronic components and for medical applications. A description of the facility with details on the achievable beam parameters, and the status and plans are presented.
In severe cases of peripheral arterial disease, tissue loss can occur and the use of vascular grafts can be necessary. However, currently, there are no suitable substitutes for application in small ...diameter vessels. The aim of this work has been to produce scaffolds with adequate properties for application as vascular substitutes. Polycaprolactone scaffolds were produced by the electrospinning technique. The surface of the scaffolds was functionalized with heparin and vascular endothelial growth factor (VEGF) and their physical-chemical properties were characterized. Human endothelial progenitor cells (EPCs) or mesenchymal stem cells (MSCs) were seeded onto the surface of the scaffolds in order to create an endothelial layer. The electrospun scaffolds exhibited mechanical properties compatible with the native arteries. The presence of heparin prevented blood coagulation on the scaffold surface. The presence of heparin and VEGF favored the adaptation of MSCs and EPCs on the scaffolds in relation to the non functionalized scaffolds. In addition, the EPCs cultivated on the scaffolds maintained the expression of CD31, CD34 and VE-cadherin genes. The results obtained in the present study suggest that electrospun scaffolds functionalized with heparin and VEGF can be applied in vascular tissue engineering. These scaffolds exhibited antithrombogenic properties and favored the development of cells on their surface. The association of heparin and VEGF with electrospun scaffolds increased EPC proliferation, favoring the formation of the endothelial layer and the regeneration of damaged vessels.
Inertial Measurement Units are present in several applications in aerospace, unmanned vehicle navigation, legged robots, and human motion tracking systems, due to their ability to estimate a body’s ...acceleration, orientation and angular rate. In contrast to rovers and drones, legged locomotion involves repeated impacts between the feet and the ground, and rapid locomotion (e.g., running) involves alternating stance and flight phases, resulting in substantial oscillations in vertical acceleration. The aim of this research is to investigate the effects of periodic low-acceleration impacts (4 g, 8 g and 16 g), which imitate the vertical motion of a running robot, on the attitude estimation of multiple Micro-Electromechanical Systems IMUs. The results reveal the presence of a significant drift in the attitude estimation of the sensors, which can provide important information during the design process of a robot (sensor selection), or during the control phase (e.g., the system will know that after a series of impacts the attitude estimations will be inaccurate).
•Study of the shadowing of coherent of polarization radiation.•Shadowing effects disappear for distances much shorter than those predicted.•The diffraction counteracts the destructive interference ...related to the shadowing.•Any electrically-polarizable medium or surface can be a source of radiation.•These studies are well-adapted to novel and compact accelerator technologies.
We report on the study of shadowing of electromagnetic fields radiated in the Terahertz (THz) region from two consecutive sources of coherent diffraction and transition radiation. In these conditions, the formation length is predicted to be ≲100 m, and shadowing effects should result in an almost complete suppression of radiated fields within distances of the order of tens of centimeters. We experimentally measured that shadowing effects disappear for distances significantly shorter than those predicted. We propose a new model that explains our experimental observations by taking into account 3D diffraction effects. These findings will have a positive impact on the beneficial use of consecutive radiators both for the generation of intense electromagnetic radiation and for beam diagnostics using coherent polarization radiation from ultra-relativistic charged particles.
This contribution describes the experimental program already undergoing and to be completed on the High Luminosity Large Hadron Collider (HL-LHC) Inner Triplet (IT) String, an important intermediate ...milestone of the HL-LHC project at CERN. First, it describes the magnet circuits of the HL-LHC IT String. Afterwards, the different systems installed to perform the experimental program are detailed. The proposed tests are defined for the validation of the cryogenic system, the full remote alignment system, the powering system, and the protection schemes of all magnets working in unison. This strategy will allow for a verification of the integrated powering system before the final installation and commissioning in the HL-LHC's underground areas.
Overview of the CLEAR plasma lens experiment Lindstrøm, C.A.; Sjobak, K.N.; Adli, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2018, Letnik:
909
Journal Article
Recenzirano
Odprti dostop
Discharge capillary-based active plasma lenses are a promising new technology for strongly focusing charged particle beams, especially when combined with novel high gradient acceleration methods. ...Still, many questions remain concerning such lenses, including their transverse field uniformity, limitations due to plasma wakefields and whether they can be combined in multi-lens lattices in a way to cancel chromaticity. These questions will be addressed in a new plasma lens experiment at the CLEAR User Facility at CERN. All the subsystems have been constructed, tested and integrated into the CLEAR beam line, and are ready for experiments starting late 2017.
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