A generative model of hyperelastic strain energy density functions for multiple tissue brain deformation

PURPOSE: Estimation of brain deformation is crucial during neurosurgery. Whilst mechanical characterisation captures stress-strain relationships of tissue, biomechanical models are limited by experimental conditions. This results in variability reported in the literature. The aim of this work was to demonstrate a generative model of strain energy density functions can estimate the elastic properties of tissue using observed brain deformation. METHODS: For the generative model a Gaussian Process regression learns elastic potentials from 73 manuscripts. We evaluate the use of neo-Hookean, Mooney-Rivlin and 1-term Ogden meta-models to guarantee stability. Single and multiple tissue experiments validate the ability of our generative model to estimate tissue properties on a synthetic brain model and in eight temporal lobe resection cases where deformation is observed between pre- and post-operative images. RESULTS: Estimated parameters on a synthetic model are close to the known reference with a root-mean-square error (RMSE) of 0.1 mm and 0.2 mm between surface nodes for single and multiple tissue experiments. In clinical cases, we were able to recover brain deformation from pre- to post-operative images reducing RMSE of differences from 1.37 to 1.08 mm on the ventricle surface and from 5.89 to 4.84 mm on the resection cavity surface. CONCLUSION: Our generative model can capture uncertainties related to mechanical characterisation of tissue. When fitting samples from elastography and linear studies, all meta-models performed similarly. The Ogden meta-model performed the best on hyperelastic studies. We were able to predict elastic parameters in a reference model on a synthetic phantom. However, deformation observed in clinical cases is only partly explained using our generative model

Plasmonic nanodevice with magnetic funcionalities: fabrication and characterization

We have designed and fabricated a nanodevice exhibiting simultaneously ferromagnetic properties of nanostructures with plasmonic properties of continuous films. Our device consists of an array of nanomagnets on top of a continuous plasmonic film. The patterned nanomagnets magnetic state is single domain and well-defined shape anisotropy. Despite the presence of the patterned media on top of the Au film, the system exhibits surface plasmon resonance characteristics of a continuous film, i.e., propagating surface plasmon-polaritons

Manipulating exciton fine-structure in quantum dots with a lateral electric field

The fine structure of the neutral exciton in a single self assembled InGaAs quantum dot is investigated under the effect of a lateral electric field. Stark shifts up to 1.5 meV, an increase in linewidth, and a decrease in photoluminescence intensity were observed due to the electric field. We show that the lateral electric field strongly affects the exciton fine structure splitting due to active manipulation of the single particle wave-functions. Remarkably, the splitting can be tuned over large values and through zero.Comment: 4 pages, 5 figure

Identification of circulating miRNA profiles that distinguish malignant pleural mesothelioma from lung adenocarcinoma

Accurate diagnosis of malignant pleura mesothelioma (MPM) is challenging. Differential diagnosis of MPM versus lung adenocarcinoma (AD) is particularly difficult, yet clinically important since the two neoplasias call for different treatment approaches. Circulating miRNA-profiling to identify miRNAs that can be used to distinguish MPM from AD has not been reported. We conducted a wide screening study of miRNA profiles in serum pools of MPM patients (N = 11), AD patients (N = 36), and healthy subjects (N = 45) to identify non-invasive biomarkers for differential diagnosis of MPM and AD, using deep sequencing. Sequencing detected up to 300 known miRNAs and up to 25 novel miRNAs species in the serum samples. Among known miRNAs, 7 were upregulated in MPM and 12 were upregulated in AD compared to healthy controls. Of these, eight were distinctive for AD and three were unique for MPM. Direct comparison of the miRNA profiles for MPM and AD revealed differences in miRNA levels that could be useful for differential diagnosis. No differentially expressed novel miRNAs were found. Further bioinformatics analysis indicated that three upregulated miRNAs in MPM are associated with the p38 pathway. There are unique alterations in serum miRNAs in MPM and AD compared to healthy controls, as well as differences between MPM and AD profiles. Differing miRNA levels between MPM and AD may be useful for differential diagnosis. A potential association to p38 pathway of three upregulated miRNAs in MPM was revealed

A fast synthesis route of boron-carbon-nitrogen ultrathin layers towards highly mixed ternary B-C-N phases

We report a direct and fast synthesis route to grow boron-carbon-nitrogen layers based on microwave-assisted plasma enhanced chemical vapour deposition (PECVD) by using methylamine borane as a single source molecular precursor. This easy and inexpensive method allows controlled and reproducible growth of B-C-N layers onto thin Cu foils. Their morphological, structural, chemical, optical and transport properties have been thoroughly characterized by a number of different microscopies, transport and spectroscopic techniques. Though disorder and segregation into C-rich and h-BN-rich domains have been observed in ultrathin flat few layers, high doping levels have been reached, inducing strong modifications of the electronic, optical and transport properties of C-rich and h-BN-rich phases. This synthesis procedure can open new routes towards the achievement of homogeneous highly mixed ternary B-C-N phase

Removal of nutrients and pesticides from agricultural runoff using microalgae and cyanobacteria

The use of pesticides in agriculture has ensured the production of different crops. However, pesticides have become an emerging public health problem for Latin American countries due to their excessive use, inadequate application, toxic characteristics, and minimal residue control. The current project evaluates the ability of two strains of algae (Chlorella and Scenedesmus sp.) and one cyanobacteria (Hapalosyphon sp.) to remove excess pesticides and other nutrients present in runoff water from rice production. Different concentrations of wastewater and carbon sources (Na2CO3 and NaHCO3 ) were evaluated. According to the results, all three strains can be grown in wastewater without dilution (100%), with a biomass concentration comparable to a synthetic medium. All three strains significantly reduced the concentration of NO3 and PO4 (95 and 85%, respectively), with no difference between Na2CO3 or NaHCO3 . Finally, Chlorella sp. obtained the highest removal efficiency of the pesticide (Chlorpyrifos), followed by Scenedesmus and Hapalosyphon sp. (100, 75, and 50%, respectively). This work shows that it is possible to use this type of waste as an alternative source of nutrients to obtain biomass and metabolites of interest, such as lipids and carbohydrates, to produce biofuels

Manejo del neonato con coartación de aorta e hipoplasia de arco

ResumenIntroducciónLa coartación aórtica del neonato puede asociar en un porcentaje importante hipoplasia del arco aórtico, llegando en algunas series al 60%.Cuando existe hipoplasia del arco aórtico distal el tratamiento estándar consiste en la resección de la zona de coartación y anastomosis termino-terminal extendida.En casos de hipoplasia severa del arco aórtico distal y arco distal largo, podría no ser suficiente con la resección y anastomosis termino-terminal extendida, por lo que sería razonable realizar alguna técnica adicional para ampliar el arco aórtico distal, evitando así un abordaje anterior, el uso de parada circulatoria con o sin perfusión cerebral selectiva y el aumento de la morbimortalidad perioperatoria.MétodosPresentamos los resultados de 4 neonatos, a los que se les realizó una ampliación del arco aórtico distal, según técnica de Amato (anastomosis latero-lateral entre las arterias carótida y subclavia izquierdas), para posteriormente resecar la zona de coartación y anastomosar la aorta descendente al arco aórtico previamente ampliado.ResultadosEn todos los casos el ecocardiograma postoperatorio mostró arco reconstruido con flujo laminar. No se ha presentado ningún caso de recoartación durante un período de seguimiento medio de 12 meses.ConclusiónConsideramos que la técnica de elección en la coartación con hipoplasia de arco distal es la resección y anastomosis termino-terminal extendida.En casos seleccionados, con arco aórtico distal muy largo y severamente hipoplásico, la técnica de Amato es una alternativa atractiva, con el objeto de evitar un abordaje anterior y el uso de CEC. Además, puede realizarse en un primer tiempo, manteniendo perfusión sistémica ductus-dependiente.AbstractIntroductionNeonatal aortic coarctation can be combined with a significant percentage of aortic arch hypoplasia, reaching 60% in some series.When there is hypoplasia of the distal aortic arch, the standard treatment consists of resection of the coarctation zone and extended end-to-end anastomosis.In cases of severe distal aortic arch hypoplasia and a long distal arch, resection and extended end-to-end anastomosis would not be sufficient, making it reasonable to perform an additional technique to widen the distal aortic arch, thus avoiding an anterior approach and interrupting the blood circulation with or without selective cerebral infusion, with the resulting risk of an increase in perioperative morbidity and mortality.MethodsThe results are presented on 4 neonates on whom a widening of the distal aortic arch was performed using the Amato technique (side-to-side anastomosis between the left carotid and subclavian arteries), in order to subsequently resect the coarctation zone and perform an anastomosis of the descending aorta to the previously widened aortic arch.ResultsThe post-operative echocardiogram showed a reconstructed arch with laminar flow in all cases. There has been no recurrence of coarctation in any of the cases during a mean follow-up of 12 months.ConclusionWe believe that resection with extended end-to-end anastomosis is the technique of choice in coarctation with distal arch hypoplasia.The Amato technique is an attractive alternative in selected cases with a very long and severely hypoplastic distal arch, with the aim of avoiding an anterior approach and the use of extracorporeal circulation. This could also be performed initially, maintaining ductal-dependent systemic perfusion

Nanometer-scale characterization of laser-driven compression, shocks, and phase transitions, by x-ray scattering using free electron lasers

We study the feasibility of using small angle X-ray scattering (SAXS) as a new experimental diagnostic for intense laser-solid interactions. By using X-ray pulses from a hard X-ray free electron laser, we can simultaneously achieve nanometer and femtosecond resolution of laser-driven samples. This is an important new capability for the Helmholtz international beamline for extreme fields at the high energy density endstation currently built at the European X-ray free electron laser. We review the relevant SAXS theory and its application to transient processes in solid density plasmas and report on first experimental results that confirm the feasibility of the method. We present results of two test experiments where the first experiment employs ultra-short laser pulses for studying relativistic laser plasma interactions, and the second one focuses on shock compression studies with a nanosecond laser system