251 research outputs found
Echo states for detailed fluctuation theorems
Detailed fluctuation theorems are statements about the probability
distribution for the stochastic entropy production along a trajectory. It
involves the consideration of a suitably transformed dynamics, such as the time
reversed, the adjoint, or a combination of these. We identify specific,
typically unique, initial conditions, called echo states, for which the final
probability distribution of the transformed dynamics reproduces the initial
distribution. In this case the detailed fluctuation theorems relate the
stochastic entropy production of the direct process to that of the transformed
one. We illustrate our results by an explicit analytical calculation and
numerical simulations for a modulated two-state quantum dot.Comment: 8 pages, 6 figures, published versio
Fluctuation theorem for entropy production during effusion of a relativistic ideal gas
The probability distribution of the entropy production for the effusion of a
relativistic ideal gas is calculated explicitly. This result is then extended
to include particle and anti-particle pair production and annihilation. In both
cases, the fluctuation theorem is verified.Comment: 6 pages, no figure
Lattice and spin excitations in multiferroic h-YMnO3
We used Raman and terahertz spectroscopies to investigate lattice and
magnetic excitations and their cross-coupling in the hexagonal YMnO3
multiferroic. Two phonon modes are strongly affected by the magnetic order.
Magnon excitations have been identified thanks to comparison with neutron
measurements and spin wave calculations but no electromagnon has been observed.
In addition, we evidenced two additional Raman active peaks. We have compared
this observation with the anti-crossing between magnon and acoustic phonon
branches measured by neutron. These optical measurements underly the unusual
strong spin-phonon coupling
Mutations in the facilitative glucose transporter GLUT10 alter angiogenesis and cause arterial tortuosity syndrome
Arterial tortuosity syndrome (ATS) is an autosomal recessive
disorder characterized by tortuosity, elongation, stenosis and
aneurysm formation in the major arteries owing to disruption
of elastic fibers in the medial layer of the arterial wall1.
Previously, we used homozygosity mapping to map a candidate
locus in a 4.1-Mb region on chromosome 20q13.1 (ref. 2).
Here, we narrowed the candidate region to 1.2 Mb containing
seven genes. Mutations in one of these genes, SLC2A10,
encoding the facilitative glucose transporter GLUT10, were
identified in six ATS families. GLUT10 deficiency is associated
with upregulation of the TGFb pathway in the arterial wall, a
finding also observed in Loeys-Dietz syndrome, in which aortic
aneurysms associate with arterial tortuosity3. The identification
of a glucose transporter gene responsible for altered arterial
morphogenesis is notable in light of the previously suggested
link between GLUT10 and type 2 diabetes4,5. Our data
could provide new insight on the mechanisms causing
microangiopathic changes associated with diabetes and
suggest that therapeutic compounds intervening with
TGFb signaling represent a new treatment strategy
Banana as adjunct in beer production: applicability and performance of fermentative parameters
Traditionally, the raw materials for beer production are barley, hops, water, and yeast, but most brewers use also different adjuncts. During the alcoholic fermentation, the contribution of aroma compounds from other ingredients to the final beer flavor depends on the wort composition, on the yeast strain, and mainly on the process conditions. In this context, banana can also be a raw material favorable to alcoholic fermentation being rich in carbohydrates and minerals and providing low acidity. In this work, the objective was to evaluate the performance of wort adjusted with banana juice in different concentrations. For this, static fermentations were conducted at 15 °C at pilot scale (140 L of medium). The addition of banana that changed the concentration of all-malt wort from 10 °P to 12 and 15 °P were evaluated (°P is the weight of the extract or the sugar equivalent in 100 g solution, at 20 °C). The results showed an increase in ethanol production, with approximately 0.4 g/g ethanol yield and 0.6 g/L h volumetric productivity after 84 h of processing when concentrated wort was used. Thus, it was concluded that banana can be used as an adjunct in brewing methods, helping in the development of new products as well as in obtaining concentrated worts.Fundação para a Ciência e a Tecnologia (FCT)EMATER-MGJohnson-DiverseyFapesp (Fundação de Amparo à
Pesquisa do Estado de São Paulo/Brasil)Wallerstein Industrial & CommercialNovozymesCAPES (Coordenação para Aperfeiçoamento do Ensino Superior/
Brasil)Malteria do ValeGRICES (Gabinete de Relações Internacionais da Ciência e do Ensino Superior/Portugal
Zebrafish type I collagen mutants faithfully recapitulate human type I collagenopathies
The type I collagenopathies are a group of heterogeneous connective tissue disorders, that are caused by mutations in the genes encoding type I collagen and include specific forms of osteogenesis imperfecta (OI) and the Ehlers-Danlos syndrome (EDS). These disorders present with a broad disease spectrum and large clinical variability of which the underlying genetic basis is still poorly understood. In this study, we systematically analyzed skeletal phenotypes in a large set of zebrafish, with diverse mutations in the genes encoding type I collagen, representing different genetic forms of human OI, and a zebrafish model resembling human EDS, which harbors a number of soft connective tissues defects, typical of EDS. Furthermore, we provide insight into how zebrafish and human type I collagen are compositionally and functionally related, which is relevant in the interpretation of human type I collagen-related disease models. Our studies reveal a high degree of intergenotype variability in phenotypic expressivity that closely correlates with associated OI severity. Furthermore, we demonstrate the potential for select mutations to give rise to phenotypic variability, mirroring the clinical variability associated with human disease pathology. Therefore, our work suggests the future potential for zebrafish to aid in identifying unknown genetic modifiers and mechanisms underlying the phenotypic variability in OI and related disorders. This will improve diagnostic strategies and enable the discovery of new targetable pathways for pharmacological intervention
Interventional radiology virtual simulator for liver biopsy
Purpose
Training in Interventional Radiology currently uses the apprenticeship model, where clinical and technical skills of invasive procedures are learnt during practice in patients. This apprenticeship training method is increasingly limited by regulatory restrictions on working hours, concerns over patient risk through trainees’ inexperience and the variable exposure to case mix and emergencies during training. To address this, we have developed a computer-based simulation of visceral needle puncture procedures.
Methods
A real-time framework has been built that includes: segmentation, physically based modelling, haptics rendering, pseudo-ultrasound generation and the concept of a physical mannequin. It is the result of a close collaboration between different universities, involving computer scientists, clinicians, clinical engineers and occupational psychologists.
Results
The technical implementation of the framework is a robust and real-time simulation environment combining a physical platform and an immersive computerized virtual environment. The face, content and construct validation have been previously assessed, showing the reliability and effectiveness of this framework, as well as its potential for teaching visceral needle puncture.
Conclusion
A simulator for ultrasound-guided liver biopsy has been developed. It includes functionalities and metrics extracted from cognitive task analysis. This framework can be useful during training, particularly given the known difficulties in gaining significant practice of core skills in patients
Inflatable structures and digital fabrication
The construction industry has changed drastically over the past several decades. In today’s age, engineers and architects aim to build bigger and lighter whilst remaining sustainable. Inflatable structures can be utilized to achieve these aims. This study investigates how to digitally manufacture inflatable structures to be more efficient. For this reason, digital manufacturing as well as casting and moulding are studied and compared. Firstly, software modelling was explored to evaluate the behaviour of elastomeric materials. 3D printing in Tango Plus FLX930 and silicone casting was compared. It was found that Tango Plus FLX930 was inadequate due to its low elasticity compared to the considered silicones. Under pneumatic loading, indeed, Tango Plus FLX930 would delaminate. Whereas, with casting and moulding silicone, the prototype could resist the required amount of internal pressures. This shows the feasibility of moulding and casting and the limitation of 3D printing fabrication techniques
- …
