Structure-preserving Gaussian denoising of FIB-SEM volumes.

FIB-SEM (Focused Ion Beam-Scanning Electron Microscopy) is an imaging technique that allows 3D ultrastructural analysis of cells and tissues at the nanoscale. The acquired FIB-SEM data are highly noisy, which makes denoising an essential step prior to volume interpretation. Gaussian filtering is a standard method in the field because it is fast and straightforward. However, it tends to blur the biological features due to its linear nature that ignores the rapid changes of the structures throughout the volume. To address this issue, we have developed a new approach to structure-preserving noise reduction for FIB-SEM. It has abilities to locally adapt the filtering to the biological structures while taking advantage of the simplicity of Gaussian filtering. It uses the Optical Flow (OF) to estimate the variations of the structural features across the volume, so that they are compensated before the subsequent filtering with a Gaussian function. As demonstrated qualitatively and objectively with datasets from different samples and acquired under different conditions, our denoising approach outperforms the standard Gaussian filtering and is competitive with state-of-the-art methods in terms of noise reduction and preservation of the sharpness of the structures.

The role of electrochemical potentials of solid-state energy emissive harvesters.

We prove that semiconductor and metallic energy-emissive harvesters, thermoradiative cells and intermediate-band thermoradiative cells are obtained from the concept of core radiative material doing different approximations. We also show that using this concept it is possible to predict new outcomes on energy-emissive harvesters. Among the new results we highlight the possible failure of the particle conservation model if used on cold-carrier energy emissive harvesters, that intermediate band solar cells must produce small output powers and the reduction of the cell power of thermoradiative cells due to multiexcitonic processes. Moreover, we explain the physical principles of the differences found between results obtained using the detailed balance method and results that are obtained without using it.

Optical flow driven interpolation for isotropic FIB-SEM reconstructions.

BACKGROUND AND OBJECTIVE: Focused Ion Beam - Scanning Electron Microscopy (FIB-SEM) allows three-dimensional ultrastructural analysis of cells and tissues at the nanoscale. The technique iteratively removes a section of the sample with a FIB and takes an SEM image from the exposed surface. The section thickness is usually higher than the image pixel size to reduce acquisition time, thus resulting in anisotropic resolution. In this work, we explore novel interpolation methods along the sectioning direction to produce isotropic resolution and facilitate proper interpretation of the FIB-SEM 3D volumes. METHODS: Classical interpolation methods are usually applied in this context under the assumption that the changes through successive images are relatively smooth. However, the actual 3D arrangement of the structures in the sample may cause significant changes in the biological features between consecutive images of the FIB-SEM stacks. We have developed a novel interpolation strategy that accounts for this variation by using the Optical Flow (OF) to estimate it. As an intermediate stage, OF-compensated images are produced by aligning the spatial regions of the biological structures. Interpolated images are then generated from these OF-compensated images. The final isotropic stack is assembled by interleaving the interpolated images with the original images of the anisotropic stack. RESULTS: OF-driven and classical interpolation methods were compared using an objective assessment based on Pearson Correlation Coefficient (PCC) and a qualitative evaluation based on visual results, using public datasets and representative anisotropy conditions. The objective assessment demonstrated that the OF-driven interpolation always yields higher PCC values, with interpolated images closer to the ground truth. The qualitative evaluation corroborated those results and confirmed that classical interpolation may blur areas with substantial changes between consecutive images whereas OF-driven interpolation provides sharpness. CONCLUSIONS: We have developed an OF-driven interpolation approach to generating FIB-SEM stacks with isotropic resolution from experimental anisotropic data. It adapts to the rapid variation of the biological structures observed through the images of the FIB-SEM stack. Our approach outperforms classical interpolation and manages to produce sharp interpolated views in cases where there are significant changes between consecutive experimental images.

Volcanic Vortex Rings: Axial Dynamics, Acoustic Features, and Their Link to Vent Diameter and Supersonic Jet Flow.

By injecting a mixture of gas and pyroclasts into the atmosphere, explosive volcanic eruptions frequently generate vortex rings, which are toroidal vortices formed by the jet's initial momentum. Here, we report high-speed imaging and acoustic measurements of vortex rings sourcing from gas-rich eruptive jets at Stromboli volcano (Italy). Volcanic vortex rings (VVRs) form at the vent together with an initial compression acoustic wave, VVRs maximum rise velocity being directly proportional to the amplitude and inversely proportional to the duration of the compression wave. The axial rise and acoustic signature of VVRs match well those predicted by recent fluid-dynamic experiments. This good match allows using the high-frequency (80-1,000 Hz) component of the jet sound and the time-dependent rise of VVRs to retrieve two key eruption parameters: the Mach number of the eruptive jets (<1.5) and vent diameter (∼0.7 m), respectively, the latter being confirmed independently by direct Uncrewed Aerial Vehicle observations.

Acoustic analysis of starting jets in an anechoic chamber: implications for volcano monitoring.

Explosive volcanic eruptions are associated with a plethora of geophysical signals. Among them, acoustic signals provide ample information about eruptive dynamics and are widely used for monitoring purposes. However, a mechanistic correlation of monitoring signals, underlying source processes and reasons for short-term variations is incomplete. Scaled laboratory experiments can mimic a wide range of explosive volcanic eruption conditions. Here, starting (non-steady) compressible gas jets are created using a shock tube in an anechoic chamber and their acoustic signature is recorded with a microphone array. Noise sources are mapped in time and frequency using wavelet analysis and their dependence from pressure ratio, non-dimensional mass supply and exit-to-throat area ratio is deciphered. We observed that the pressure ratio controls the establishment of supersonic conditions and their duration, and influences the interaction between shock, shear layer, and vortex ring. The non-dimensional mass supply affects the duration of the discharge, the maximum velocity of the flow, and the existence of a trailing jet. Lower values of exit-to-throat area ratio induce a faster decay of the acoustic fingerprint of the jet flow. The simplistic experiments presented here, and their acoustic analysis will serve as an essential starting point to infer source conditions prior to and during impulsive volcanic eruptions.

Impact of COVID-19 outbreak in reperfusion therapies of acute ischaemic stroke in northwest Spain.

BACKGROUND AND PURPOSE: Spain has been one of the countries more heavily stricken by SARS-CoV-2, which has had huge implications for stroke care. The aim was to analyse the impact of the COVID-19 epidemic outbreak on reperfusion therapies for acute ischaemic stroke in the northwest of Spain. METHODS: This was a Spanish multicentre retrospective observational study based on data from tertiary hospitals of the NORDICTUS network. All patients receiving reperfusion therapy for ischaemic stroke between 30 December 2019 and 3 May 2020 were recorded, and their baseline, clinical and radiological characteristics, extra- and intra-hospital times of action, Code Stroke activation pathway, COVID-19 status, reperfusion rate, and short-term outcome before and after the setting of the emergency state were analysed. RESULTS: A total of 796 patients received reperfusion therapies for ischaemic stroke. There was a decrease in the number of patients treated per week (46.5 patients per week vs. 39.0 patients per week, P = 0.043) and a delay in out-of-hospital (95.0 vs. 110.0 min, P = 0.001) and door-to-needle times (51.0 vs. 55.0, P = 0.038). Patients receiving endovascular therapy obtained less successful reperfusion rates (92.9% vs. 86.6%, P = 0.016). COVID-19 patients had more in-hospital mortality. CONCLUSION: A decrease in the number of patients benefiting from reperfusion therapies was found, with a delay in out-of-hospital and door-to-needle times and worse reperfusion rates in northwest Spain. COVID-19 patients had more in-hospital mortality.

The supporting role of the teres major muscle, an additional component in glenohumeral stability? An anatomical and radiological study.

Muscle coordination plays an important role in glenohumeral stability. The rotator cuff and the long head of the biceps are considered the primary dynamic stabilizers muscles. However, the fact that a subgroup of patients with a massive tear in the rotator cuff were able to keep a normal function, should make us question this traditional view. We hypothesize that the teres major which is also a monoarticular scapulohumeral muscle, although it is not part of the conjoined tendon of the rotator cuff, can play a role in glenohumeral stability by a direct support of the humeral head generated by the particular posteroanterior location of this muscle under the humeral head and which, as far as we know, has not been written up previously. This particular effect could appear while the arm is being lifted and the humeral head could be leaning on against the teres major muscle belly underneath it. An anatomical a radiological study was carried out to substantiate our hypothesis. Two cadaver specimens were used for the anatomical study. Frist body was studied through conventional dissection. The second body was analysed through sectional anatomy. Then a radiological study was carried out using magnetic resonance imaging in a healthy male volunteer. Both anatomically and radiologically, the anteroinferior surface of the humeral head was showed firmly resting against the muscle belly of the teres major, to the point of misshaping it from 110 degrees of arm elevation with external rotation. The specific contribution of this effect to the glenohumeral stability needs to be confirmed by further studies and can help us to prevent the high incidence of glenohumeral dislocations.

Preliminary analysis of Diffusion Coefficient Measurements in ternary mIXtures 4 (DCMIX4) experiment on board the International Space Station.

In the frame of the Diffusion Coefficient Measurements in ternary mIXtures 4 (DCMIX4) project the thermodiffusion experiments were conducted on the International Space Station (ISS) in the Selectable Optical Diagnostics Instrument (SODI) which is on orbit since 2009. We describe the results of the preliminary analysis of images downloaded during the execution of DCMIX4 in order to check the quality of the running experiments and, if needed, adjust the experiment parameters for the following runs. The quick analysis of raw data showed that they are meaningful and will allow to obtain the transport coefficients of examined ternary and binary mixtures.

Delocalization and heat transport in multidimensional trapped ion systems.

We study the connection between heat transport properties of systems coupled to different thermal baths in two separate regions and their underlying nonequilibrium dynamics. We consider classical systems of interacting particles that may exhibit a certain degree of delocalization and whose effective dimensionality can be modified through the controlled variation of a global trapping potential. We focus on Coulomb crystals of trapped ions, which offer a versatile playground to shed light on the role that spatial constraints play on heat transport. We use a three-dimensional model to simulate the trapped ion system and show in a numerically rigorous manner to what extent heat transport properties could be feasibly tuned across the structural phase transitions among the linear, planar zigzag, and helical configurations. By solving the classical Langevin equations of motion, we analyze the steady state spatial distributions of the particles, the temperature profiles, and total heat flux through the various structural phase transitions that the system may experience. The results evidence a clear correlation between the degree of delocalization of the internal ions and the emergence of a nonzero gradient in the temperature profiles. The signatures of the phase transitions in the total heat flux as well as the optimal spatial configuration for heat transport are shown.

TomoEED: fast edge-enhancing denoising of tomographic volumes.

Summary: TomoEED is an optimized software tool for fast feature-preserving noise filtering of large 3D tomographic volumes on CPUs and GPUs. The tool is based on the anisotropic nonlinear diffusion method. It has been developed with special emphasis in the reduction of the computational demands by using different strategies, from the algorithmic to the high performance computing perspectives. TomoEED manages to filter large volumes in a matter of minutes in standard computers. Availability and implementation: TomoEED has been developed in C. It is available for Linux platforms at http://www.cnb.csic.es/%7ejjfernandez/tomoeed. Supplementary information: Supplementary data are available at Bioinformatics online.

Long-term Prognosis After Lung Transplantation: A Monocentric Study in 510 Patients.

INTRODUCTION: Lung transplantation is the final treatment option in patients with respiratory failure. Morbidity and mortality rates associated with the management of complications is high despite advances. Postoperative complications include acute transplant rejection, bronchiolitis obliterans, and infections. Because of that, the success of this treatment option depends on the correct choice of donor and candidates to receive a transplant. OBJECTIVE: This study aims to perform a survival analysis of transplanted patients in our center and determine predictive variables of mortality. PATIENTS AND METHODS: This study is a retrospective assessment of data collected from 510 patients at the Hospital University Reina Sofía from October 1993 to December 31, 2016. Patients who were retransplanted were excluded. We collected data regarding basal characteristics of the donors and candidates to receive a transplant. We analyzed the impact in terms of future survival of basal variables from donor and donor recipients. RESULTS: Five hundred ten patients were included (average age 44 ± 17 years, 69% male), with a maximum follow-up period of 21.6 years (average follow-up 4.52 years, interquartile ratio: 0.13 to 6.97 years). Two hundred twenty-seven patients died (54.3% of the total amount). The influence of donor's basal characteristics on mortality was analyzed; moreover, the relationship between basal variables and survival were analyzed using univariate analysis. Available variables were analyzed through multivariate analysis. CONCLUSION: Lung transplantation is a treatment option with an acceptable risk of morbidity and mortality. Increased awareness of features of evolution could help to reduce postoperative complications.

Coupling biological detection to liquid chromatography: a new tool in drug discovery.

Procedures to characterize drugs that can be obtained from plant extracts or combinatorial chemistry are tedious, and they consume considerable resources (e.g., animals) and time. Thus, we have looked for a way to streamline this process. We describe here a novel system for the pre-characterization of drugs based on liquid chromatography coupled to biological detection using perifused or perfused organs. This novel system allows the on-line detection of pharmacologically active substances in hydrosoluble mixtures from vegetal extracts or combinatorial chemistry libraries. Depending on the volume of drug solution and concentration of the samples, the procedure can work through either medium pressure liquid chromatography or HPLC, and it enables the fingerprints of drugs to be assessed based on their contractile activity on combinations of different isolated tissues. As an example, we show how the system can identify active fractions from an extract of Stevia rebaudiana Bertoni, an activity that was later associated with rebaudioside N. Coupling liquid chromatography to biological detection offers a rapid way to focus attention on active products in complex samples, mostly from hydrosoluble species, helping to considerably reduce the time and cost of the pre-characterization of drugs.

[Progressive encephalitis due to anti-DPPX antibodies: a case with good response to treatment with rituximab]. / Encefalitis progresiva por anticuerpos anti-DPPX: un caso con buena respuesta al tratamiento con rituximab.

TITLE: Encefalitis progresiva por anticuerpos anti-DPPX: un caso con buena respuesta al tratamiento con rituximab.

Detection of a chemical cue from the host seaweed Laurencia dendroidea by the associated mollusc Aplysia brasiliana.

Chemical cues from sessile hosts can attract mobile and associated organisms and they are also impotant to maintain associations and overall biodiversity, but the identity and molecular structures of these chemicals have been little explored in the marine environment. Secondary metabolites are recognized as possible chemical mediators in the association between species of Laurencia and Aplysia, but the identity of the compounds has not been established. Here, for the first time, we experimentally verify that the sesquiterpene (+)-elatol, a compound produced by the red seaweed Laurencia dendroidea, is a chemical cue attracting the associated sea hare Aplysia brasiliana. In addition to revealing the nature of the chemical mediation between these two species, we provide evidence of a chemical cue that allows young individuals of A. brasiliana to live in association with L. dendroidea. This study highlights the importance of chemical cues in Laurencia-Aplysia association.

Venous-to-arterial carbon dioxide difference in the resuscitation of patients with severe sepsis and septic shock: A systematic review. / La diferencia venoarterial de dióxido de carbono en la reanimación de pacientes con sepsis grave y shock séptico: una revisión sistemática.

INTRODUCTION: The way to assess tissue perfusion during the resuscitation of patients with severe sepsis and septic shock is a current subject of research and debate. Venous oxygen saturation and lactate concentration have been the most frequently used criteria, though they involve known limitations. The venous-to-arterial difference of carbon dioxide (pCO2 delta) is a parameter than can be used to indicate tissue perfusion, and its determination therefore may be useful in these patients. METHODS: A qualitative systematic review of the literature was made, comprising studies that assessed pCO2 delta in adult patients with severe sepsis or septic shock, and published between January 1966 and November 2016 in the Medline-PubMed, Embase-Elsevier, Cochrane Library, and LILACS databases. There was no language restriction. The PRISMA statement was followed, and methodological quality was evaluated. RESULTS: Twelve articles were included, all of an observational nature, and including 10 prospective studies (9 published since 2010). Five documented greater mortality among patients with high pCO2 delta values, in 3 cases even when achieving venous oxygen saturation targets. In 4 studies, a high pCO2 delta was related to lower venous oxygen saturation and higher lactate levels, and another 3 documented lesser percentage lactate reductions. CONCLUSION: The parameter pCO2 delta has been more frequently assessed in the management of patients with severe sepsis during the last few years. The studies demonstrate its correlation to mortality and other clinical outcomes, defining pCO2 delta as a useful tool in the management of these patients.

Diagnosing neuroleukemiosis: Is there a role for 18F-FDG-PET/CT?

An imaging case is presented on a patient referred to our department for an 18F-FDG-PET/CT, as a paraneoplastic syndrome was suspected due to his clinical situation. He had a history of acute myeloid leukemia (AML) treated two years earlier, with sustained complete remission to date. 18F-FDG-PET/CT findings revealed hypermetabolism in almost all nerve roots, suggesting meningeal spread, consistent with the subsequent MRI findings. Cerebrospinal fluid (CSF) findings confirmed a leptomeningeal reactivation of AML. Although not many studies have evaluated the role of 18F-FDG-PET/CT in leukemia, it is a noninvasive tool for detecting extramedullary sites of disease and a good imaging alternative for those patients on whom an MRI cannot be performed.

La diferencia venoarterial de dióxido de carbono en la reanimación de pacientes con sepsis grave y shock séptico: una revisión sistemática / The venoarterial difference of carbon dioxide in the resuscitation of patients with severe sepsis and septic shock: a systematic review

Introducción La forma de evaluar la perfusión tisular durante la reanimación de pacientes con sepsis grave y shock séptico es tema de estudio y debate en la actualidad. La saturación venosa de oxígeno y el lactato han sido los criterios más utilizados; sin embargo, presentan limitaciones reconocidas. La diferencia venoarterial de dióxido de carbono (delta de pCO2) es una variable que puede indicar el estado de perfusión tisular, por lo que su evaluación puede ser útil en estos pacientes. Métodos Revisión sistemática cualitativa de la literatura que incluyó estudios que evaluaron el delta de pCO2 en pacientes adultos con sepsis grave o shock séptico, publicados entre enero de 1966 y noviembre de 2016 en las bases de datos Medline-PubMed, Embase-Elsevier, Cochrane Library y LILACS. No tuvo restricción de idiomas. Se siguió la declaración PRISMA y se evaluó la calidad metodológica. Resultados Doce estudios fueron incluidos, todos observacionales, 10 prospectivos, 9 publicados a partir del 2010. Cinco documentaron una mayor mortalidad entre pacientes con delta de pCO2 alto, en 3 incluso cuando conseguían metas de saturación venosa de oxígeno. En 4 estudios, un delta de pCO2 alto se relacionó con una menor saturación venosa de oxígeno y niveles mayores de lactato, y otros 3 documentaron un menor porcentaje de disminución de lactato. Conclusión El delta de pCO2 ha sido evaluado en el manejo de los pacientes con sepsis grave y shock séptico con mayor frecuencia en los últimos años. Los estudios demuestran su relación con la mortalidad y otros desenlaces clínicos, de tal forma que puede ser una herramienta útil en el manejo de estos pacientes.

Heteroleptic mononuclear compounds of ruthenium(ii): synthesis, structural analyses, in vitro antitumor activity and in vivo toxicity on zebrafish embryos.

The limitations of platinum complexes in cancer treatment have motivated the extensive investigation into other metal complexes such as ruthenium. We herein present the synthesis and characterization of a new family of ruthenium compounds 1a-5a with the general formula [Ru(bipy)2L][CF3SO3]2 (bipy = 2,2'-bipyridine; L = bidentate ligand: N,N; N,P; P,P; P,As) which have been characterized by elemental analysis, ES-MS, 1H and 31P-{1H} NMR, FTIR and conductivity measurements. The molecular structures of four Ru(ii) complexes were determined by single crystal X-ray diffraction. All compounds displayed moderate cytotoxic activity in vitro against human A2780 ovarian, MCF7 breast and HCT116 colorectal tumor cells. Compound 5a was the most cytotoxic compound against A2780 and MCF7 tumor cells with an IC50 of 4.75 ± 2.82 µM and 20.02 ± 1.46 µM, respectively. The compounds showed no cytotoxic effect on normal human primary fibroblasts but rather considerable selectivity for A2780, MCF7 and HCT116 tumor cells. All compounds induce apoptosis and autophagy in A2780 ovarian carcinoma cells and some nuclear DNA fragmentation. All compounds interact with CT-DNA with intrinsic binding constants in the order 1a > 4a > 2a > 3a > 5a. The observed hyperchromic effect may be due to the electrostatic interaction between positively charged cations and the negatively charged phosphate backbone at the periphery of the double helix-CT-DNA. Interestingly, compound 1a shows a concentration dependent DNA double strand cleavage. In addition in vivo toxicity has been evaluated on zebrafish embryos unveiling the differential toxicity between the compounds, with LC50 ranging from 8.67 mg L-1 for compound 1a to 170.30 mg L-1 for compound 2a.