Carotenoids are isoprenoids compounds widely distributed in foods. A difference of carotenoids relative to other food bioactives is that some can be converted into compounds exhibiting vitamin A ...activity, which is essential for humans. Besides, they are more versatile as they are also natural pigments, antioxidants and can be involved in health-promoting actions. Lately, they are also attracting interest in relation to skin beauty. Their importance for different industry sector (foods, feeds, pharmaceutical, cosmetics) is therefore indisputable. Carotenoids can be obtained by different approaches including extraction from appropriate sources or synthesis.
Due to their advantages (easiness for the optimization of conditions to obtain higher yields, versatility, etc.) fermentative processes have been long studied and even applied at industrial scale for their production. On the other hand, food fermentation is an ancient approach that usually results in products with new characteristics, enhanced quality and/or better preservation. However, the impact of such processes on the carotenoids present in the foods and their bioavailability are not well understood yet.
In this work, approaches used to obtain carotenoids by fermentation are reviewed as well as the impact of food fermentation on these compounds. Some research needs are also pinpointed, including further studies on the effect of food fermentations on the potential bioavailability of carotenoids, the production of carotenoids of commercial interest other than β-carotene, lycopene or astaxanthin or that of carotenoid cleavage derivatives.
•Alcoholic or lactic acid fermentations do not cause important losses of carotenoids.•Increased carotenoids after fermentation due to facilitated extractability.•Fermentations can lead to increased aroma compounds from carotenoids.•β-carotene or lycopene are produced from fermentation (B. trispora).•Fermentation can produce “uncommon” “unusual” carotenoids such as torulene or torularhodin.
Fourier-Based Imaging for Multistatic Radar Systems Alvarez, Yuri; Rodriguez-Vaqueiro, Yolanda; Gonzalez-Valdes, Borja ...
IEEE transactions on microwave theory and techniques,
08/2014, Letnik:
62, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Fourier-based methods for monostatic and bistatic setups have been widely used for high-accuracy radar imaging. However, the multistatic configuration has several characteristics that make Fourier ...processing more challenging: 1) a nonuniform grid in k-space, which requires multidimensional interpolation methods, and 2) image distortion when the incident spherical wave is approximated by a plane wave. This contribution presents a Fourier-based imaging method for multistatic systems, solving the aforementioned limitations: the first, by using k-space partitioning and applying interpolation in each domain; the second, by approximating the spherical wave with multiple plane waves. Both solutions are fully parallelizable, thus allowing calculation time savings. Validation and benchmarking with a synthetic aperture radar backpropagation algorithm have been performed through 2-D and 3-D simulation-based examples. Imaging results from radar measurements have been assessed.
Accurate predictions of fluid flow, mass transport, and reaction rates critically impact the efficiency and reliability of subsurface exploration and sustainable use of subsurface resources. ...Quantitative dynamical sensing and imaging can play a pivotal role in the ability to make such predictions. Geophysical thermoacoustic technology has the potential to provide the aforementioned capabilities, since it builds upon the principle that electromagnetic and mechanical wave fields can be coupled through a thermodynamic process. In this letter, we present laboratory experiments featuring the efficacy of thermoacoustic imaging in the monitoring of preferential flow of water in porous media. Our laboratory experimental equipment can be readily packaged in a form factor that fits in a borehole, and the use of multiple acoustic transducers—which can be combined with volumetric coding techniques—has the potential to provide quasi‐real‐time imaging (0.5 Hz video rate) of regions in close proximity (a few meters) of an open field well.
Plain Language Summary
Multiphysics subsurface sensing and imaging technology has the potential to provide unique insights to better understand multiphase flow and transport in porous media in 4D (time and space). Conventional high‐resolution, laboratory‐based imaging technology—such as X‐ray or MRI—require power‐hungry and often bulky equipment; the latter limits their use in open field experiments and challenges their ability to perform real‐time image reconstruction. Acoustics Doppler imaging has been used for real‐time flow velocity monitoring in biomedical applications; however, the relationship between fluid saturation in porous media and measured acoustic pressure still requires further investigation. In this letter we show how microwave‐induced thermoacoustic (TA) imaging technology can be applied to monitor water distribution in sand. In contrast to traditional acoustic imaging, the proposed TA method exhibits a dominant monotonic relationship between the degree of water saturation and the measured amplitude of the TA pressure. Our experimental results show the efficacy of TA technology for imaging 2D water distribution profiles in sand. The reconstructed TA images are in good agreement with the optical ground truth water distribution map, thus illustrating the feasibility of the proposed method for real‐world field applications in agricultural and hydrological sciences.
Key Points
The increased water saturation level in sand, silt, and clay leads to a higher thermoacoustics wave amplitude
The reconstructed thermoacoustics images match well with the optical ground truth for water‐saturated sand
Thermoacoustics imaging enables real‐time monitoring of water distribution in subsurface sand
Conventional security screening systems cannot operate in real time and often suffer from false alarms due to the profile-only imaging without further analysis on the object material properties. ...Reflectarrays were recently proposed as devices capable of performing real-time security screening using a single-frequency radar signal. This article presents first a physical optics (PO)-based simulation method to facilitate the design of a multireflectarray system. Then, an object material characterization method using geometrical optics (GO) is derived for such a system. The characterization process not only retrieves the complex relative permittivity of the object but also improves its profile reconstruction in terms of a more accurate thickness. Both simulations and experiments are carried out to verify the effectiveness and efficiency of the proposed methods. Primary results show great potentials for security screening, especially in scenarios where the inspection of human bodies for threat materials, such as narcotics and explosives, is required.
High-performance millimeter-wave (mm-wave) multiple-in-multiple-out (MIMO) radars have been using efficient multiplexing with increasingly complicated radar waveforms, where conventional hardware ...architectures suffer from inevitably high design complexity and cost. This article presents a new software-defined mm-wave multistatic imaging system which provides great efficiency and flexibility to generate and process complicated radar waveforms. A general system block diagram and its signal model are proposed to use space-time-coded orthogonal frequency-division multiplexing (OFDM) for simultaneous MIMO transmission at the same time and frequency. The space-time coding (STC) is designed based on the Hadamard matrix which allows simple decoupling and decoding for imaging processing. A radar prototype is designed to validate the proposed system architecture, which operates at 83.5 GHz with a frequency bandwidth of 4.8 GHz. The mm-wave front-end consists of a metal-printed 8-by-8 waveguide array with a small element-separation of 9 mm to form 64 virtual channels for three-dimensional imaging. Experimental results show good imaging performance, giving great potential to design future cost-effective high-performance mm-wave imaging with efficient multiplexing.
Treatment options for patients with secondary acute myeloid leukemia (sAML) and AML with myeloid-related changes (AMLMRC) aged 60 to 75 years are scarce and unsuitable. A pivotal trial showed that ...CPX-351 improved complete remission with/without incomplete recovery (CR/CRi) and overall survival (OS) as compared with standard "3+7" regimens. We retrospectively analyze outcomes of 765 patients with sAML and AML-MRC aged 60 to 75 years treated with intensive chemotherapy, reported to the PETHEMA registry before CPX-351 became available. The CR/CRi rate was 48%, median OS was 7.6 months (95% confidence interval CI: 6.7-8.5) and event-free survival (EFS) 2.7 months (95% CI: 2-3.3), without differences between intensive chemotherapy regimens and AML type. Multivariate analyses identified age ≥70 years, Eastern Cooperative Oncology Group performance status ≥1 as independent adverse prognostic factors for CR/CRi and OS, while favorable/intermediate cytogenetic risk and NPM1 were favorable prognostic factors. Patients receiving allogeneic stem cell transplant (HSCT), autologous HSCT, and those who completed more consolidation cycles showed improved OS. This large study suggests that classical intensive chemotherapy could lead to similar CR/CRi rates with slightly shorter median OS than CPX-351.
The use of solid cavities around electromagnetic sources has been recently reported as a mechanism to provide enhanced images at microwave frequencies. These cavities are used as measurement ...randomizers; and they compress the wave fields at the physical layer. As a result of this compression, the amount of information collected by the sensing array through the different excited modes inside the resonant cavity is increased when compared to that obtained by no-cavity approaches. In this work, a two-dimensional cavity, having multiple openings, is used to perform such a compression for ultrasound imaging. Moreover, compressive sensing techniques are used for sparse signal retrieval with a limited number of operating transceivers. As a proof-of-concept of this theoretical investigation, two point-like targets located in a uniform background medium are imaged in the presence and the absence of the cavity. In addition, an analysis of the sensing capacity and the shape of the point spread function is also carried out for the aforementioned cases. The cavity is designed to have the maximum sensing capacity given different materials and opening sizes. It is demonstrated that the use of a cavity, whether it is made of plastic or metal, can significantly enhance the sensing capacity and the point spread function of a focused beam. The imaging performance is also improved in terms cross-range resolution when compared to the no-cavity case.
A fractional factorial design was used to evaluate the effects of temperature, frying time, blanching treatment and the thickness of potato slices on acrylamide content in crisps. The design was used ...on freshly harvested and four-month stored potatoes. The critical factors found were temperature and frying time, and the interaction between blanching treatment and slice thickness. Once frying conditions were selected, an acrylamide content of 725 and 1030 mg kg
was found for non-stored and 4-month stored tubers, with adequate textural parameters in both cases. The difference in concentration is related to storage conditions, which must be controlled in order to control acrylamide levels. Bioaccesibility studies demonstrated that acrylamide concentration remained at 70%, and reductions took place mainly at the intestinal phase, as a result of reaction with nucleophilic compounds.
This letter presents the simulated design and signal processing algorithms of a novel single-transceiver compressive reflector antenna for high-sensing-capacity imaging. The compressive reflector ...antenna (CRA) generates a spatial code in the imaging region, which is dynamically changed by using a mechanical rotation of the reflector. The scattered data measured by the single transceiver is processed using compressive sensing techniques in order to perform a 3-D reconstruction of the object under test. Preliminary results show that the CRA outperforms traditional reflector antennas in terms of sensing capacity and reconstruction accuracy.
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