771 research outputs found
Hypo-Loop Container Freight Transport: PART II Macro-Imagineering New World Macro-Projects
The proposed Hypo-Loop megaproject, which would tunnel under the DariĂ©n Gap, could provide a safe conduit for the transport of container freight and passengers between Panama and Colombia. The advantage of a tunnel linking Central America with South America is that transport would be via an underground low-pressure steel tube that alleviates terrestrial compromises of the environmentally sensitive DariĂ©n Gap ecosystem, which is recognized as an important natural environmental linkage between Panama and Colombia. This tunnel link is technically feasible using today’s modern tunnel boring methods that are amenable to providing infrastructure for mixed modal train transport. The DariĂ©n Gap Hypo-Loop Macro-project has the potential to provide environmentally safe transport across sensitive ecosystems by tunneling beneath them and at the same time opening up expansive transfer of goods and materials in the New World. Initiation and completion of the Hypo-Loop under the DariĂ©n Gap landscape would bring this region into the 21st Century as a showcase for enhancing the quality of life and improving New World economic systems.Key-words: Panama, Columbia, Atrato River, Hypo-Loop, passenger pods, containerized freight shipment, DariĂ©n Gap, Panama Canal, tunneling technology.===================================================================== O megaprojeto Hypo-Loop proposto, com tunelamento sob o DariĂ©n Gap, poderia fornecer um canal seguro para o transporte de contĂŞineres e passageiros entre o Panamá e a ColĂ´mbia. A vantagem de um tĂşnel que liga a AmĂ©rica Central Ă AmĂ©rica do Sul Ă© que o transporte seria por meio de um tubo de aço subterrâneo de baixa pressĂŁo que evitaria o comprometimento do ecossistema DariĂ©n Gap, reconhecido como um importante vĂnculo ambiental natural entre o Panamá e a ColĂ´mbia. Esse  tĂşnel Ă© tecnicamente viável pelos mĂ©todos modernos de perfuração, capazes de fornecer infraestrutura para um modal misto. O macroprojeto DariĂ©n Gap Hypo-Loop tem o potencial de fornecer transporte ambientalmente seguro atravĂ©s de ecossistemas sensĂveis, encapsulando-o sob eles e, ao mesmo tempo, abrindo um amplo intercâmbio de bens e materiais no Novo Mundo. No cenário do DariĂ©n Gap, a realização do Hypo-Loop faria dessa regiĂŁo uma vitrine sobre a melhoria da qualidade de vida e dos sistemas econĂ´micos do Novo Mundo no sĂ©culo XXI.Palavras-chave: Panamá, ColĂ´mbia, Rio Atrato, Hypo-Loop, cápsulas de passageiros, remessa de carga em contĂŞiner, DariĂ©n Gap, Canal do Panamá, tecnologia de tunelamento
Control strategies for integration of electric motor assist and functional electrical stimulation in paraplegic cycling: Utility for exercise testing and mobile cycling
AIM: The aim of this study was to investigate feedback
control strategies for integration of electric motor assist and functional electrical stimulation (FES) for paraplegic cycling, with particular focus on development of a testbed for exercise testing in FES cycling, in which both cycling cadence and workrate are simultaneously well controlled and contemporary physiological measures of exercise performance derived. A second aim was
to investigate the possible benefits of the approach for mobile, recreational cycling.
METHODS: A recumbent tricycle with an auxiliary electric motor is used, which is adapted for paraplegic users, and instrumented for stimulation control. We propose a novel integrated control strategy which simultaneously provides feedback control of leg power output (via automatic adjustment of stimulation intensity) and cycling cadence (via electric motor control). Both loops are
designed using system identification and analytical (model-based) feedback design methods. Ventilatory and pulmonary gas exchange response profiles are derived using a portable system for real-time breath-by-breath acquisition.
RESULTS:We provide indicative results from one paraplegic subject in which a series of feedback-control tests illustrate accurate control of cycling cadence, leg power control, and external disturbance rejection. We also provide physiological response profiles from a submaximal exercise step test and a maximal incremental exercise test, as facilitated by the control strategy.
CONCLUSION: The integrated control strategy is effective in facilitating
exercise testing under conditions of well-controlled cadence
and power output. Our control approach significantly extends the
achievable workrate range and enhances exercise-test sensitivity
for FES cycling, thus allowing a more stringent characterization
of physiological response profiles and estimation of key parameters
of aerobic function.We further conclude that the control approach
can significantly improve the overall performance of mobile recreational
cycling
Exuberant “Magic Carpet” Giga-Project Macro-Imagineering: The Arabian/Persian Gulf Shallow Draft PV-Raft Giga-Project
Processos naturais e atividades antropogĂŞnicas afetam de forma variável a diversidade climática e  ecossistĂŞmica das nações ao redor do Golfo PĂ©rsico-Arábico. O Magic Carpet Giga-Project, proposto como uma contramedida de enfrentamento da aridez dos ambientes regionais, Ă© concebido como uma vasta jangada flutuante com painĂ©is fotovoltaicos, disposta sobre o Golfo. Conectada por cabos elĂ©tricos a instalações terrestres, a energia poderia ser fornecida para cidades e para aplicações industriais que incluiriam enormes usinas de dessalinização de água do mar para uso municipal em geral. A adaptação espacial e marĂtima na forma de caminhos de aproximação e desvios será necessária em razĂŁo das rotas marĂtimas existentes, bem como do acesso adequado Ă s plataformas da indĂşstria petrolĂfera offshore que pontilham o Golfo. Os macroprojetos “The Line” e “The Loop” serĂŁo áreas bem delimitadas com vegetação controlada pelo clima, enquanto o “Magic Carpet” pode se tornar um esteio de dessalinização e fornecimento de eletricidade para a futura infraestrutura básica de cada estado do Golfo.Palavras-chave: Macroengenharia, Arábia Saudita, NEOM, jangada fotovoltaica flutuante, Golfo PĂ©rsico-Arábico, Golfo da CalifĂłrnia. =========================================================================== Abstract: Natural processes and anthropogenic activities variably affect climate variability and meteorological drought in ecosystem-nations surrounding the Arabian-Persian Gulf. The Magic Carpet Giga-project, proposed as a counter measure to aridification of the regional environments, is envisaged as a vast floating PV-panel studded raft in the Gulf. Connected by electrical cables to land-based facilities, power could be provided for cities and industrial applications that would include enormous seawater desalination plants for municipal and commercial applications. Spatial and sea lane accommodation in the form of approach ways and bypasses will be necessary for designated sea-lanes, as well as according access to in-place offshore petroleum industry platforms dotting the Gulf. “The Line” and “The Loop” macro-projects are to be climate-controlled, vegetated enclosures whilst the “Magic Carpet” may become an electricity-desalination mainstay of the future basic infrastructure of every Gulf ecosystem-state.Keywords: Giga-project, Saudi Arabia, NEOM, floating photovoltaic raft, Arabian-Persian Gulf, Gulf of California
Mir-96 and miR-183 differentially regulate neonatal and adult post-infarct neovascularisation
Following myocardial infarction (MI), the adult heart has minimal regenerative potential. Conversely, the neonatal heart can undergo extensive regeneration, and neovascularisation capacity was hypothesised to contribute to this difference. Here, we demonstrate the higher angiogenic potential of neonatal compared to adult mouse cardiac endothelial cells (MCECs) in vitro and use this difference to identify candidate microRNAs (miRs) regulating cardiac angiogenesis after MI. MiR expression profiling revealed miR-96 and miR-183 upregulation in adult compared to neonatal MCECs. Their overexpression decreased the angiogenic potential of neonatal MCECs in vitro and prevented scar resolution and neovascularisation in neonatal mice after MI. Inversely, their inhibition improved the angiogenic potential of adult MCECs, and miR-96/miR-183 knock-out mice had increased peri-infarct neovascularisation. In silico analyses identified anillin (ANLN) as a direct target of miR-96 and miR-183. In agreement, Anln expression declined following their overexpression and increased after their inhibition in vitro. Moreover, ANLN expression inversely correlated with miR-96 expression and age in cardiac ECs of cardiovascular patients. In vivo, ANLN-positive vessels were enriched in the peri-infarct area of miR-96/miR-183 knock-out mice. These findings identify miR-96 and miR-183 as regulators of neovascularisation following MI and miR-regulated genes such as anillin as potential therapeutic targets for cardiovascular disease
Role of Esrrg in the Fibrate-Mediated Regulation of Lipid Metabolism Genes in Human ApoA-I Transgenic Mice
We have used a new ApoA-I transgenic mouse model to identify by global gene expression profiling, candidate genes that affect lipid and lipoprotein metabolism in response to fenofibrate treatment. Multilevel bioinformatical analysis and stringent selection criteria (2-fold change, 0% false discovery rate) identified 267 significantly changed genes involved in several molecular pathways. The fenofibrate-treated group did not have significantly altered levels of hepatic human APOA-I mRNA and plasma ApoA-I compared with the control group. However, the treatment increased cholesterol levels to 1.95-fold mainly due to the increase in high-density lipoprotein (HDL) cholesterol. The observed changes in HDL are associated with the upregulation of genes involved in phospholipid biosynthesis and lipid hydrolysis, as well as phospholipid transfer protein. Significant upregulation was observed in genes involved in fatty acid transport and β-oxidation, but not in those of fatty acid and cholesterol biosynthesis, Krebs cycle and gluconeogenesis. Fenofibrate changed significantly the expression of seven transcription factors. The estrogen receptor-related gamma gene was upregulated 2.36-fold and had a significant positive correlation with genes of lipid and lipoprotein metabolism and mitochondrial functions, indicating an important role of this orphan receptor in mediating the fenofibrate-induced activation of a specific subset of its target genes.National Institutes of Health (HL48739 and HL68216); European Union (LSHM-CT-2006-0376331, LSHG-CT-2006-037277); the Biomedical Research Foundation of the Academy of Athens; the Hellenic Cardiological Society; the John F Kostopoulos Foundatio
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