This study investigates the morphology, microstructure and surface composition of Diesel engine exhaust particles. The state of agglomeration, the primary particle size and the fractal dimension of ...exhaust particles from petroleum Diesel (petrodiesel) and biodiesel blends from microalgae, cotton seed and waste cooking oil were investigated by means of high resolution transmission electron microscopy. With primary particle diameters between 12 and 19 nm, biodiesel blend primary particles are found to be smaller than petrodiesel ones (21 ± 2 nm). Also it was found that soot agglomerates from biodiesels are more compact and spherical, as their fractal dimensions are higher, e.g. 2.2 ± 0.1 for 50% algae biodiesel compared to 1.7 ± 0.1 for petrodiesel. In addition, analysis of the chemical composition by means of x-ray photoelectron spectroscopy revealed an up to a factor of two increased oxygen content on the primary particle surface for biodiesel. The length, curvature and distance of graphene layers were measured showing a greater structural disorder for biodiesel with shorter fringes of higher tortuosity. This change in carbon chemistry may reflect the higher oxygen content of biofuels. Overall, it seems that the oxygen content in the fuels is the underlying reason for the observed morphological change in the resulting soot particles.
Aim
To explore the use of hyperspectral imaging (HSI) to predict healing of diabetic foot ulcers in patients with diabetes.
Methods
We used a HSI technique that incorporated novel software to account ...for tissue scattering of light, and was validated using blood samples of varying oxygen saturation assessed by blood gas analysis. HSI was then performed on a population newly presenting with diabetic foot ulcers to a specialist clinic, and associations were sought with healing at 12 and 24 weeks.
Results
The correlation between the results of HSI and blood gas analysis was strong (r = 0.994). A total of 43 patients (mean ± sd age 62.7 ± 12.2 years; 31 men, 12 women; 37 with Type 2 diabetes, six with Type 1 diabetes) with foot ulcers were included in the prospective clinical study and underwent HSI within 16 days of presentation. In all, 26 ulcers healed within 12 weeks and 28 within 24 weeks. There was a negative association between tissue oxygenation assessed by HSI at baseline and healing by 12 weeks (P = 0.009), and this was observed in both infected and non‐infected ulcers. There was a significant positive correlation between oxygenation assessed by HSI and time to healing (P = 0.03). No correlations were observed at 24 weeks.
Conclusions
These findings suggest that HSI may predict healing in routine practice. The fact that the correlation between HSI and healing was negative could be explained by HSI being a measure of oxygenation of haemoglobin and there may be an inverse relationship between this and the oxygenation of extravascular tissue in people with neuropathy and/or microvascular disease.
What's new?
Hyperspectral imaging (HSI) provides a simple, non‐invasive measure of haemoglobin oxygenation and we found a very strong correlation between the results of HSI and oxygen saturation determined by blood gas analysis in vitro.
In studying people with diabetes newly referred with diabetic foot ulcers, we have also found a strong negative correlation between oxygenation of haemoglobin as reflected by HSI and healing of the ulcers within 12 weeks. We postulate that this correlation is negative because of the effect of microvascular shunting on the oxygenation of haemoglobin in this population.
These observations suggest that HSI may predict early healing in people with diabetic foot ulcers and could therefore be used to select those less likely to heal for more intensive assessment at an earlier stage.
Thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC Savic, N.; Bergbreiter, L.; Breuer, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2017, Letnik:
845
Journal Article
Recenzirano
The ATLAS experiment will undergo a major upgrade of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) foreseen to start around 2025. Thin planar pixel modules are promising ...candidates to instrument the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. New designs of the pixel cells, with an optimized biasing structure, have been implemented in n-in-p planar pixel productions with sensor thicknesses of 270μm. Using beam tests, the gain in hit efficiency is investigated as a function of the received irradiation fluence. The outlook for future thin planar pixel sensor productions will be discussed, with a focus on thin sensors with a thickness of 100 and 150μm and a novel design with the optimized biasing structure and small pixel cells (50×50 and 25×100μm2). These dimensions are foreseen for the new ATLAS read-out chip in 65nm CMOS technology and the fine segmentation will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. To predict the performance of 50×50μm2 pixels at high η, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angle with respect to the short pixel direction. Results on cluster shapes, charge collection- and hit efficiency will be shown.
There is an abundance of plastic materials used in the widest range of applications, such as packaging, machine parts, biomedical devices and components, etc. However, most materials used today are ...non-decomposable in the environment, producing a huge burden on ecosystems. The search for better, safer alternatives is still on. Here we present a detailed analysis of a simple, cheap, non-toxic, even edible, eco-friendly material, which can be easily manufactured, laser patterned and used for the fabrication of complex structures. The base substance is gelatin which is made photoresponsive by adding plasticizers and sensitizers. The resulting films were analyzed with respect to their optical, thermal and mechanical properties, which can be modified by a slight variation of chemical composition. The material is optimized for rapid laser-manufacturing of elastic microstructures (lenses, gratings, cantilevers, etc.) without any waste or residues. Overall, the material properties were tailored to increase photothermal responsivity, improve the surface quality and achieve material homogeneity, transparency and long-term stability (as verified using electron microscopy, infrared spectroscopy and differential scanning calorimetry).
COVID-19 is associated with an increased incidence of pulmonary embolism (PE). Elevated D-dimer levels are linked to an increased risk of PE and poor clinical outcome. We reported a case of PE in a ...COVID-19 patient with normal D-dimer levels and conducted a review of the literature on the subject.
A 38-year-old man with no prior comorbidities returned to the COVID-19 outpatient clinic 36 hours after being discharged from the hospital, where he had been treated for COVID-19 pneumonia. He reported a sudden feeling of dyspnea and chest pain. The physical examination was unremarkable. No new changes were detected on the chest X-ray. D-dimer and cardiac-specific markers values were within the referent range. The patient underwent an urgent computerized tomography pulmonary angiography which revealed signs of bilateral arterial thrombosis. He was treated with a therapeutic dose of low molecular weight heparin and discharged after 15 days, with a recommendation to use a direct oral anticoagulant.
Healthcare professionals should be aware that PE can occur as a late complication of COVID-19. Clinical suspicion of PE should lead physicians to use additional diagnostic methods to confirm or rule out PE, even if D-dimer levels are within the referent range.
Pharmacovigilance education and reporting of adverse drug reactions (ADRs) are important competencies that healthcare sciences students should develop before completing their studies and entering ...clinical practice. Since students frequently lack adequate knowledge in this area and fail to recognize the importance of ADRs monitoring and reporting, the aim of this study was to develop and validate a unique and reliable instrument for assessing health sciences students' knowledge and attitudes toward pharmacovigilance and ADRs reporting.
A cross-sectional observational study was conducted from February to July 2021 to examine students' knowledge and attitudes toward pharmacovigilance activities. Students of medicine, dentistry, pharmacy, and nursing science of three faculties in the Autonomous Province of Vojvodina, Serbia were examined. A total of 211 of them completed the specially designed, three-section questionnaire (Demographic data section, Pharmacovigilance Knowledge test, PVKT, and Pharmacovigilance Attitude Questionnaire, PVAQ). The questionnaire was posted on the Google Forms platform, and the link was distributed to respondents via the official websites and social networks of all three faculties.
Findings demonstrated good psychometric properties and reliability of the questionnaire. Six questions were removed from the PVKT after item analyses. After excluding these items, the calculated ordinal alpha of the final version of the PVKT, which included 14 items, was good (αord = 0.83), as were other statistical indicators. PVAQ reliability testing also revealed great performance of this questionnaire-calculated ordinal alpha for two PVAQ subscales was excellent (αord = 0.91, for both scales).
This questionnaire has favorable validity and reliability in assessing healthcare sciences students' knowledge and attitudes toward pharmacovigilance and ADRs reporting.
The ATLAS experiment will undergo around the year 2025 a replacement of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a new 5-layer pixel system. Thin planar pixel ...sensors are promising candidates to instrument the innermost region of the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. The sensors of 50-150 mum thickness, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests. In particular active edge sensors have been investigated. The performance of two different versions of edge designs are compared: the first with a bias ring, and the second one where only a floating guard ring has been implemented. The hit efficiency at the edge has also been studied after irradiation at a fluence of 10 super(15) n sub(eq)/cm super(2). Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 mum super(2) pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angles with respect to the short pixel direction. Results on the hit efficiency in this configuration are discussed for different sensor thicknesses.
In view of the high luminosity phase of the LHC (HL-LHC) to start operation around 2026, a major upgrade of the tracker system for the ATLAS experiment is in preparation. The expected neutron ...equivalent fluence of up to 2.4×1016 1 MeV neq./cm2 at the innermost layer of the pixel detector poses the most severe challenge. Thanks to their low material budget and high charge collection efficiency after irradiation, modules made of thin planar pixel sensors are promising candidates to instrument these layers. To optimise the sensor layout for the decreased pixel cell size of 50×50μm2, TCAD device simulations are being performed to investigate the charge collection efficiency before and after irradiation. In addition, sensors of 100−150μm thickness, interconnected to FE-I4 read-out chips featuring the previous generation pixel cell size of 50×250μm2, are characterised with testbeams at the CERN-SPS and DESY facilities. The performance of sensors with various designs, irradiated up to a fluence of 1×1016 neq./cm2, is compared in terms of charge collection and hit efficiency. A replacement of the two innermost pixel layers is foreseen during the lifetime of HL-LHC . The replacement will require several months of intervention, during which the remaining detector modules cannot be cooled. They are kept at room temperature, thus inducing an annealing. The performance of irradiated modules will be investigated with testbeam campaigns and the method of accelerated annealing at higher temperatures.
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