53 research outputs found
Analysis of the main passive soft tissues associated with adult acquired flatfoot deformity development: A computational modeling approach
Adult acquired flatfoot deformity (AAFD) is a pathology with a wide range of treatment options. Physicians decide the best treatment based on their experience, so the process is entirely subjective. A better understanding of soft tissue stress and its contribution in supporting the plantar arch could help to guide the clinical decision. Traditional experimental trials cannot consistently evaluate the contribution of each tissue. Therefore, in this research a 3-Dimensional FE foot model was reconstructed from a normal patient in order to measure the stress of the passive stabilizers of the arch, and its variation in different scenarios related with intermediate stages of AAFD development. All bones, the plantar fascia (PF), cartilages, plantar ligaments and the spring ligament (SL) were included, respecting their anatomical distribution and biomechanical characteristics. An AAFD evaluation scenario was simulated. The relative contribution of each tissue was obtained comparing each result with a normal case. The results show that PF is the main tissue that prevents the arch elongation, while SL mainly reduces the foot pronation. Long and short plantar ligaments play a secondary role in this process. The stress increment on both PF and SL when one of two fails suggests that these tissues complement each other. These findings support the theory that regards the tibialis posterior tendon as a secondary actor in the arch maintenance, compared with the PF and the SL, because this tendon is overstretched by the hindfoot pronation around the talonavicular joint. This approach could help to improve the understanding of AAFD
Pensamiento crĂtico para el Pensamiento gráfico
PASSMORE (1967) define el Pensamiento CrĂtico como un proceso que es a la vez reflexivo e imaginativo, cualidades imprescindibles en todo proceso de diseño. En este artĂculo nos centramos en la utilizaciĂłn del Pensamiento CrĂtico para mejorar lo que se ha dado en llamar Pensamiento Gráfico. El trabajo se divide en dos partes complementarias. En la primera, se formula un marco teĂłrico en torno a los conceptos de Pensamiento CrĂtico y Pensamiento Gráfico, para proponer una metodologĂa de enseñanza de la ingenierĂa que relacione ambos conceptos. En la segunda, se aplican dichos aspectos al estudio de una herramienta esencial dentro del proceso de diseño, el diagrama, y a la manera de proyectar en la contemporaneidad. - Critical thinking is defined by PASSMORE (1967) as a process that is both reflexive and imaginative, essencial aspects of the design process. This paper focuses on the use of Critical Thinking to improve what we call Graphic Thinking. The content is two fold. The first part establishes a theoretical framework around the concepts of Critical Thinking and Graphic Thinking, in order to propose a methodology for engineering education through the combination of both concepts. The second one deals with those concepts, which are applied to one of the basic tools within the design process, the diagram, analysing through it the contemporary way of designing
Capsule endoscopy interpretation: the role of physician extenders
Background and aims: capsule endoscopy (CE) allows for a
new era in small-bowel examination. Nevertheless, physicians’
time for CE-interpretation remains longer than desirable. Alternative
strategies to physicians have not been widely investigated.
The aim of this study was to evaluate the accuracy of physician
extenders in CE-interpretation.
Material and methods: one CE-experienced gastroenterologist
and two physician extenders reviewed independently 20 CEprocedures.
Each reader was blinded to the findings of their colleagues.
A consensus formed by the readers and a second
CE-experienced gastroenterologist was used as gold standard.
Number, type and location of images selected, character of CEexams
and their relationship with indications were recorded. Gastric
emptying time (GEt), small-bowel transit time (SBTt) and time
spent by readers were also noted.
Results: sensitivity and specificity for “overall” lesions was 79
and 99% for the gastroenterologist; 86 and 43% for the nurse;
and 80 and 57% for the resident. All 34 “major” lesions considered
by consensus were found by the readers. Agreement between
consensus and readers for images classification and procedures
interpretation was good to excellent (Îş from 0.55 to 1). No
significant differences were found in the GEt and SBTt obtained
by consensus and readers. The gastroenterologist was faster than
physician extenders (mean time spent was 51.9 ± 13.5 minutes
versus 62.2 ± 19 and 60.9 ± 17.1 for nurse and resident, respectively;
p < 0.05).
Conclusions: physician extenders could be the perfect complement
to gastroenterologists for CE-interpretation but gastroenterologists
should supervise their findings. Future cost-efficacy
analyses are required to assess the benefits of this alternative
A REVIEW OF RECORDING TECHNOLOGIES FOR DIGITAL FABRICATION IN HERITAGE CONSERVATION
Digital tools have brought new techniques for recording and fabrication allowing for the augmentation of traditional processes in repairs and restorations. Traditional mechanical and chemical techniques require physical contact to the artefacts of interest, while LiDAR Scanning, photogrammetry and structured light scanning provide non-invasive solutions. Analog recording technologies have always informed fabrication processes, but contemporary digital recording can produce complete geometry for fabrication. In this paper, we discuss recording and fabrication technologies and how they have been applied for heritage conservation
Efecto de la osteotomĂa medializante de calcáneo sobre tejidos blandos de soporte del arco plantar: un estudio computacional
Medializing calcaneal osteotomy forms part of the treatment options for adult acquired flat foot. The structural correction that is achieved is widely known. However, the effect of this procedure on the soft tissues that support the plantar arch has been little studied, since it is not possible to quantify experimentally the tension and deformation variations generated. Therefore, the objective of this study was to evaluate the effect of medializing calcaneal osteotomy on the soft tissue that supports the plantar arch, using a computational model of the human foot designed with a clinical approach. The proposed finite element model was reconstructed from computerized tomography images of a healthy patient. All the bones of the foot, the plantar fascia, cartilages, plantar ligaments and the calcaneus-navicular ligament were included, respecting their anatomical distribution and biomechanical properties. Simulations were performed emulating the monopodal support phase of the human walk of an adult. The effect on each tissue was evaluated according to clinical and biomechanical criteria. The results show that calcaneal osteotomy reduces the tension normally generated on the evaluated tissues, with the effect on the calcaneus-navicular ligament and the plantar fascia being the most notable. The deformation results obtained are consistent with experimental tests and clinical knowledge. The versatility of this model allows the objective assessment of different conditions and supports decision making for the treatment of adult acquired flat foot in middle and advanced stages
Intratumoral injection of dendritic cells engineered to secrete interleukin-12 by recombinant adenovirus in patients with metastatic gastrointestinal carcinomas.
PURPOSE:
To evaluate the feasibility and safety of intratumoral injection of autologous dendritic cells (DCs) transfected with an adenovirus encoding interleukin-12 genes (AFIL-12) for patients with metastatic gastrointestinal carcinomas. Secondarily, we have evaluated biologic effects and antitumoral activity.
PATIENTS AND METHODS:
Seventeen patients with metastatic pancreatic (n = 3), colorectal (n = 5), or primary liver (n = 9) malignancies entered the study. DCs were generated from CD14+ monocytes from leukapheresis, cultured and transfected with AFIL-12 before administration. Doses from 10 x 10(6) to 50 x 10(6) cells were escalated in three cohorts of patients. Patients received up to three doses at 21-day intervals.
RESULTS:
Fifteen (88%) and 11 of 17 (65%) patients were assessable for toxicity and response, respectively. Intratumoral DC injections were mainly guided by ultrasound. Treatment was well tolerated. The most common side effects were lymphopenia, fever, and malaise. Interferon gamma and interleukin-6 serum concentrations were increased in 15 patients after each treatment, as well as peripheral blood natural killer activity in five patients. DC transfected with AFIL-12 stimulated a potent antibody response against adenoviral capsides. DC treatment induced a marked increase of infiltrating CD8+ T lymphocytes in three of 11 tumor biopsies analyzed. A partial response was observed in one patient with pancreatic carcinoma. Stable disease was observed in two patients and progression in eight patients, with two of the cases fast-progressing during treatment.
CONCLUSION:
Intratumoral injection of DC transfected with an adenovirus encoding interleukin-12 to patients with metastatic gastrointestinal malignancies is feasible and well tolerated. Further studies are necessary to define and increase clinical efficacy
ÂżQuĂ© es la fotografĂa? Anexo a una experiencia docente
Depto. de Ciencias de la ComunicaciĂłn AplicadaFac. de Ciencias de la InformaciĂłnpu
Reversal of Synapse Degeneration by Restoring Wnt Signaling in the Adult Hippocampus
Synapse degeneration occurs early in neurodegenerative diseases and correlates strongly with cognitive decline in Alzheimer's disease (AD). The molecular mechanisms that trigger synapse vulnerability and those that promote synapse regeneration after substantial synaptic failure remain poorly understood. Increasing evidence suggests a link between a deficiency in Wnt signaling and AD. The secreted Wnt antagonist Dickkopf-1 (Dkk1), which is elevated in AD, contributes to amyloid-β-mediated synaptic failure. However, the impact of Dkk1 at the circuit level and the mechanism by which synapses disassemble have not yet been explored. Using a transgenic mouse model that inducibly expresses Dkk1 in the hippocampus, we demonstrate that Dkk1 triggers synapse loss, impairs long-term potentiation, enhances long-term depression, and induces learning and memory deficits. We decipher the mechanism involved in synapse loss induced by Dkk1 as it can be prevented by combined inhibition of the Gsk3 and RhoA-Rock pathways. Notably, after loss of synaptic connectivity, reactivation of the Wnt pathway by cessation of Dkk1 expression completely restores synapse number, synaptic plasticity, and long-term memory. These findings demonstrate the remarkable capacity of adult neurons to regenerate functional circuits and highlight Wnt signaling as a targetable pathway for neuronal circuit recovery after synapse degeneration
Thermoelectric generator (TEG) technologies and applications
2021 The Author(s). Nowadays humans are facing difficult issues, such as increasing power costs, environmental pollution and global warming. In order to reduce their consequences, scientists are concentrating on improving power generators focused on energy harvesting. Thermoelectric generators (TEGs) have demonstrated their capacity to transform thermal energy directly into electric power through the Seebeck effect. Due to the unique advantages they present, thermoelectric systems have emerged during the last decade as a promising alternative among other technologies for green power production. In this regard, thermoelectric device output prediction is important both for determining the future use of this new technology and for specifying the key design parameters of thermoelectric generators and systems. Moreover, TEGs are environmentally safe, work quietly as they do not include mechanical mechanisms or rotating elements and can be manufactured on a broad variety of substrates such as silicon, polymers and ceramics. In addition, TEGs are position-independent, have a long working life and are ideal for bulk and compact applications. Furthermore, Thermoelectric generators have been found as a viable solution for direct generation of electricity from waste heat in industrial processes. This paper presents in-depth analysis of TEGs, beginning with a comprehensive overview of their working principles such as the Seebeck effect, the Peltier effect, the Thomson effect and Joule heating with their applications, materials used, Figure of Merit, improvement techniques including different thermoelectric material arrangements and technologies used and substrate types. Moreover, performance simulation examples such as COMSOL Multiphysics and ANSYS-Computational Fluid Dynamics are investigated
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