56 research outputs found
Prebiotic effects of olive pomace powders in the gut: In vitro evaluation of the inhibition of adhesion of pathogens, prebiotic and antioxidant effects
Supplementary data related to this article can be found at https:// doi.org/10.1016/j.foodhyd.2020.106312Olive pomace is a biowaste rich in polyphenols and insoluble dietary fibre with high potential to develop new value chains towards a sustainable and circular bioeconomy. Regarding gut health, olive pomace phenolics and insoluble dietary fibre (after possible fermentation) could act as antioxidants, antimicrobial and prebiotic agents. These potential beneficial effects on the gut were analysed for two powders from olive pomace: liquid-enriched powder (LOPP) - mostly source of phenolics - and pulp-enriched powder (POPP) - main source of insoluble dietary fibre. LOPP and POPP were subjected to an in vitro simulated gastrointestinal digestion followed by in vitro faecal fermentation. The undigested fraction retained in the colon was analysed regarding its potential antioxidant, antimicrobial and prebiotic effects. LOPP and POPP did not impact the gut microbiota diversity negatively, showing a similar ratio of Firmicutes/Bacteroidetes compared to a positive control (FOS). LOPP exhibit a positive (similar to FOS) effect on the Prevotella spp./Bacteroides spp. ratio. Both powders also promoted more the production of short-chain fatty acids (mainly acetate?>?butyrate?>?propionate) than FOS. Both powders showed also significant total phenolic content and oxygen radical absorbance capacity during faecal fermentation until 48?h. Besides that, these powders showed mucin-adhesion inhibition ability against pathogens, principally POPP against Bacillus cereus (22.03?±?2.45%) and Listeria monocytogenes (20.01?±?1.93%). This study demonstrates that olive pomace powders have prebiotic effects on microbiota, including the stimulation of short-chain fatty acids production, potential antioxidant and antimicrobial activity which could improve human gut health.Tˆania I. B. Ribeiro thanks the FCT - Fundação para a Ciência e Tecnologia, Portugal and Association BLC3 – Technology and Innovation Campus, Centre Bio R&D Unit for the PhD Grant SFRH/BDE/108271/2015. This work was supported by National Funds from FCT - Fundação para a Ciência e a Tecnologia, Portugal through the project MULTI-BIOREFINERY - SAICTPAC/0040/2015 (POCI-01-0145-FEDER- 016403). We would also like to thank the scientific collaboration under the FCT project UID/Multi/50016/2019.info:eu-repo/semantics/publishedVersio
A study of multi-standard radio transmitters for GSM/WCDMA/LTE base stations
Les stations de base de télécommunications contemporaines pour les réseaux GSM / EDGE, WCDMA / HSPA et LTE sont de plus en plus complexes et à forte intensité énergétique. La solution privilégiée est un émetteur véritablement multi-standard. Modernes émetteurs des stations de base sont souvent multi-standard, en ce qu'ils peuvent supporter différentes normes ou de modes air-interface. Cependant, ce n'est pas réalisé par le fonctionnement simultané des normes différentes ou des «modes», mais par des moyens de reconfiguration, qui sont inefficaces et coûteux. Nous envisageons un émetteur entièrement multi-mode pratique capable de supporter simultanément GSM / EDGE, WCDMA / HSPA et LTE transporteurs. L'évolution des normes 3GPP vers un fonctionnement multi-mode est au stade embryonnaire. Pour contribuer à cet effort, notre travail revisite l'architecture traditionnelle de l'émetteur de station de base macro-cellule afin d'analyser et de définir les exigences de performance pour une plate-forme de radio cellulaire multi-standard. Notre analyse et la conception du système identifie également un goulot d'étranglement potentiel dans la chaîne multi-mode proposé, dont l'analyse est présentée. En conséquence, et enfin, nous proposons la conception d'un gain variable analogique modulateur en quadrature qui contourne le goulot d'étranglement, en soulignant la portée pour le développement futur et la validation de ce travail. Ce travail apporte également en avant quelques problèmes au niveau du système et met également en lumière les défis dans le fonctionnement des stations de base multi-standard.Contemporary telecommunication Base-Stations for GSM/EDGE, WCDMA/HSPA and LTE are increasingly complex and energy intensive. The favoured solution is a truly multi-standard transmitter known as a single Radio Access Network (single-RAN). Modern base station transmitters are often multi-standard, in that they can support different air-interface standards or modes. However, this is achieved not through concurrent operation of the different standards or 'modes', but by means of reconfiguration, which is inefficient and expensive. We envision a practical, fully multi-mode transmitter capable of simultaneously supporting GSM/EDGE, WCDMA/HSPA and LTE carriers. The evolution of 3GPP standards towards multi-mode operation is in the nascent stage. To contribute to this effort, our work revisits the architecture of the traditional macro-cell Base-Station transmitter in order to analyse and define performance requirements for a multi-standard cellular radio platform. Our system analysis and design also identifies a potential bottleneck in the proposed multi-mode chain, for which analysis is presented. Consequently and lastly, we propose the conceptual design of a variable-gain Analog Quadrature Modulator that bypasses the bottleneck, highlighting scope for future development and validation of this work. This work also brings forth some system-level issues and also highlights challenges in the operation of multi-standard Base-Stations. Some of these include multi-mode signal crest-factor reduction, carrier-to-carrier interference mitigation, per-carrier power-control, etc
Nano LEGO®
Self-Assembly has predominantly been nature's unique tool for building remarkable entities. This thesis shows how this versatile tool can be utilised for building devices that are useful to mankind. Starting with advanced fuel cells which produce clean energy in a highly efficient way; continuing on to carbon nano networks which are one of the strongest materials known to man; and finally supermagnets which have the potential to revolutionise the medical and electronics industry.Chemical EngineeringApplied Science
Avances : revista científica
Contemporary telecommunication Base-Stations for GSM/EDGE, WCDMA/HSPA and LTE are increasingly complex and energy intensive. The favoured solution is a truly multi-standard transmitter known as a single Radio Access Network (single-RAN). Modern base station transmitters are often multi-standard, in that they can support different air-interface standards or modes. However, this is achieved not through concurrent operation of the different standards or 'modes', but by means of reconfiguration, which is inefficient and expensive. We envision a practical, fully multi-mode transmitter capable of simultaneously supporting GSM/EDGE, WCDMA/HSPA and LTE carriers. The evolution of 3GPP standards towards multi-mode operation is in the nascent stage. To contribute to this effort, our work revisits the architecture of the traditional macro-cell Base-Station transmitter in order to analyse and define performance requirements for a multi-standard cellular radio platform. Our system analysis and design also identifies a potential bottleneck in the proposed multi-mode chain, for which analysis is presented. Consequently and lastly, we propose the conceptual design of a variable-gain Analog Quadrature Modulator that bypasses the bottleneck, highlighting scope for future development and validation of this work. This work also brings forth some system-level issues and also highlights challenges in the operation of multi-standard Base-Stations. Some of these include multi-mode signal crest-factor reduction, carrier-to-carrier interference mitigation, per-carrier power-control, etc.Les stations de base de télécommunications contemporaines pour les réseaux GSM / EDGE, WCDMA / HSPA et LTE sont de plus en plus complexes et à forte intensité énergétique. La solution privilégiée est un émetteur véritablement multi-standard. Modernes émetteurs des stations de base sont souvent multi-standard, en ce qu'ils peuvent supporter différentes normes ou de modes air-interface. Cependant, ce n'est pas réalisé par le fonctionnement simultané des normes différentes ou des «modes», mais par des moyens de reconfiguration, qui sont inefficaces et coûteux. Nous envisageons un émetteur entièrement multi-mode pratique capable de supporter simultanément GSM / EDGE, WCDMA / HSPA et LTE transporteurs. L'évolution des normes 3GPP vers un fonctionnement multi-mode est au stade embryonnaire. Pour contribuer à cet effort, notre travail revisite l'architecture traditionnelle de l'émetteur de station de base macro-cellule afin d'analyser et de définir les exigences de performance pour une plate-forme de radio cellulaire multi-standard. Notre analyse et la conception du système identifie également un goulot d'étranglement potentiel dans la chaîne multi-mode proposé, dont l'analyse est présentée. En conséquence, et enfin, nous proposons la conception d'un gain variable analogique modulateur en quadrature qui contourne le goulot d'étranglement, en soulignant la portée pour le développement futur et la validation de ce travail. Ce travail apporte également en avant quelques problèmes au niveau du système et met également en lumière les défis dans le fonctionnement des stations de base multi-standard
Linearity considerations for multi-standard cellular base station transmitters
Contemporary cellular base stations are becoming increasingly multi-standard for improved efficiency and manageability. Primary among prospective multi-standard base station deployments will be those that are reconfigurable but also capable of simultaneous transmission of several cellular signals. The simultaneous transmission of multiple cellular signals however poses a challenge for design, in particular the linearity requirements of the transceiver. In order to identify the feasibility of multi-mode transmission, we present an overview of transmitter non-linearity (OIP3) requirements for future multi-standard, multi-carrier, macro-cell base stations based on first-order approximations, highlighting the dynamic range issue. Simulation and measurement results are also presented
Linearity considerations for multi-standard cellular base station transmitters
Contemporary cellular base stations are becoming increasingly multi-standard for improved efficiency and manageability. Primary among prospective multi-standard base station deployments will be those that are reconfigurable but also capable of simultaneous transmission of several cellular signals. The simultaneous transmission of multiple cellular signals however poses a challenge for design, in particular the linearity requirements of the transceiver. In order to identify the feasibility of multi-mode transmission, we present an overview of transmitter non-linearity (OIP3) requirements for future multi-standard, multi-carrier, macro-cell base stations based on first-order approximations, highlighting the dynamic range issue. Simulation and measurement results are also presented
D-Lactic Acidosis: An Underrecognized Complication of Short Bowel Syndrome
D-lactic acidosis or D-lactate encephalopathy is a rare condition that occurs primarily in individuals who have a history of short bowel syndrome. The unabsorbed carbohydrates act as a substrate for colonic bacteria to form D-lactic acid among other organic acids. The acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, hence giving rise to a vicious cycle. D-lactic acid accumulation in the blood can cause neurologic symptoms such as delirium, ataxia, and slurred speech. Diagnosis is made by a combination of clinical and laboratory data including special assays for D-lactate. Treatment includes correcting the acidosis and decreasing substrate for D-lactate such as carbohydrates in meals. In addition, antibiotics can be used to clear colonic flora. Although newer techniques for diagnosis and treatment are being developed, clinical diagnosis still holds paramount importance, as there can be many confounders in the diagnosis as will be discussed subsequently
EVM considerations for convergent multi-standard cellular base-station transmitters
International audienceModern cellular base stations are becoming increasingly multi-carrier and multi-standard/multi-mode for improved efficiency and manageability. Primary among prospective multi-mode base station deployments will be those that are reconfigurable but also capable of simultaneous transmission of several types of cellular signals. However, unified or convergent-transmitter design is challenging, particularly with the small specified tolerances for signal distortion. We present an analysis of the Error Vector Magnitude (EVM) specifications for GSM/EDGE, UMTS and LTE, based on simulated EVM sensitivity to various distortions, focusing on a convergent transmit chain for multi-standard, multi-carrier macro-cell base stations. These analyses illustrate a method of deriving preliminary radio transmitter performance (phase noise, IQ imbalances, noise floor etc.) requirements, alongside helping to expose bottlenecks and performance tradeoffs necessary to optimize power consumption. A preliminary distribution of distortion or performance among the blocks is presented, to achieve the less than 5% multi-mode EVM budget, for worst-case scenarios
EVM considerations for convergent multi-standard cellular base-station transmitters
International audienceModern cellular base stations are becoming increasingly multi-carrier and multi-standard/multi-mode for improved efficiency and manageability. Primary among prospective multi-mode base station deployments will be those that are reconfigurable but also capable of simultaneous transmission of several types of cellular signals. However, unified or convergent-transmitter design is challenging, particularly with the small specified tolerances for signal distortion. We present an analysis of the Error Vector Magnitude (EVM) specifications for GSM/EDGE, UMTS and LTE, based on simulated EVM sensitivity to various distortions, focusing on a convergent transmit chain for multi-standard, multi-carrier macro-cell base stations. These analyses illustrate a method of deriving preliminary radio transmitter performance (phase noise, IQ imbalances, noise floor etc.) requirements, alongside helping to expose bottlenecks and performance tradeoffs necessary to optimize power consumption. A preliminary distribution of distortion or performance among the blocks is presented, to achieve the less than 5% multi-mode EVM budget, for worst-case scenarios
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