Sustainable Solutions for Sea Monitoring With Robotic Sailboats: N-Boat and F-Boat Twins.

Strategic management and production of internal energy in autonomous robots is becoming a research topic with growing importance, especially for platforms that target long-endurance missions, with long-range and duration. It is fundamental for autonomous vehicles to have energy self-generation capability to improve energy autonomy, especially in situations where refueling is not viable, such as an autonomous sailboat in ocean traversing. Hence, the development of energy estimation and management solutions is an important research topic to better optimize the use of available energy supply and generation potential. In this work, we revisit the challenges behind the project design and construction for two fully autonomous sailboats and propose a methodology based on the Restricted Boltzmann Machine (RBM) in order to find the best way to manage the supplementary energy generated by solar panels. To verify the approach, we introduce a case study with our two developed sailboats that have planned payload with electric and electronics, and one of them is equipped with an electrical engine that may eventually help with the sailboat propulsion. Our current results show that it is possible to augment the system confidence level for the potential energy that can be harvested from the environment and the remaining energy stored, optimizing the energy usage of autonomous vehicles and improving their energy robustness.

Multivariate data driven prediction of COVID-19 dynamics: Towards new results with temperature, humidity and air quality data.

Since the start of the COVID-19 pandemic many studies investigated the correlation between climate variables such as air quality, humidity and temperature and the lethality of COVID-19 around the world. In this work we investigate the use of climate variables, as additional features to train a data-driven multivariate forecast model to predict the short-term expected number of COVID-19 deaths in Brazilian states and major cities. The main idea is that by adding these climate features as inputs to the training of data-driven models, the predictive performance improves when compared to equivalent single input models. We use a Stacked LSTM as the network architecture for both the multivariate and univariate model. We compare both approaches by training forecast models for the COVID-19 deaths time series of the city of São Paulo. In addition, we present a previous analysis based on grouping K-means on AQI curves. The results produced will allow achieving the application of transfer learning, once a locality is eventually added to the task, regressing out using a model based on the cluster of similarities in the AQI curve. The experiments show that the best multivariate model is more skilled than the best standard data-driven univariate model that we could find, using as evaluation metrics the average fitting error, average forecast error, and the profile of the accumulated deaths for the forecast. These results show that by adding more useful features as input to a multivariate approach could further improve the quality of the prediction models.

Silicon Microchannel-Driven Raman Scattering Enhancement to Improve Gold Nanorod Functions as a SERS Substrate toward Single-Molecule Detection.

The investigation of enhanced Raman signal effects and the preparation of high-quality, reliable surface-enhanced Raman scattering (SERS) substrates is still a hot topic in the SERS field. Herein, we report an effect based on the shape-induced enhanced Raman scattering (SIERS) to improve the action of gold nanorods (AuNRs) as a SERS substrate. Scattered electric field simulations reveal that bare V-shaped Si substrates exhibit spatially distributed interference patterns from the incident radiation used in the Raman experiment, resulting in constructive interference for an enhanced Raman signal. Experimental data show a 4.29 increase in Raman signal intensity for bare V-shaped Si microchannels when compared with flat Si substrates. The combination of V-shaped microchannels and uniform aggregates of AuNRs is the key feature to achieve detections in ultra-low concentrations, enabling reproducible SERS substrates having high performance and sensitivity. Besides SIERS effects, the geometric design of V-shaped microchannels also enables a "trap" to the molecule confinement and builds up an excellent electromagnetic field distribution by AuNR aggregates. The statistical projection of SERS spectra combined with the SIERS effect displayed a silhouette coefficient of 0.83, indicating attomolar (10-18 mol L-1) detection with the V-shaped Si microchannel.

Room-Temperature Negative Differential Resistance in Surface-Supported Metal-Organic Framework Vertical Heterojunctions.

The advances of surface-supported metal-organic framework (SURMOF) thin-film synthesis have provided a novel strategy for effectively integrating metal-organic framework (MOF) structures into electronic devices. The considerable potential of SURMOFs for electronics results from their low cost, high versatility, and good mechanical flexibility. Here, the first observation of room-temperature negative differential resistance (NDR) in SURMOF vertical heterojunctions is reported. By employing the rolled-up nanomembrane approach, highly porous sub-15 nm thick HKUST-1 films are integrated into a functional device. The NDR is tailored by precisely controlling the relative humidity (RH) around the device and the applied electric field. The peak-to-valley current ratio (PVCR) of about two is obtained for low voltages (<2 V). A transition from a metastable state to a field emission-like tunneling is responsible for the NDR effect. The results are interpreted through band diagram analysis, density functional theory (DFT) calculations, and ab initio molecular dynamics simulations for quasisaturated water conditions. Furthermore, a low-voltage ternary inverter as a multivalued logic (MVL) application is demonstrated. These findings point out new advances in employing unprecedented physical effects in SURMOF heterojunctions, projecting these hybrid structures toward the future generation of scalable functional devices.

Ultrahigh-Gain Organic Electrochemical Transistor Chemosensors Based on Self-Curled Nanomembranes.

Organic electrochemical transistors (OECTs) are technologically relevant devices presenting high susceptibility to physical stimulus, chemical functionalization, and shape changes-jointly to versatility and low production costs. The OECT capability of liquid-gating addresses both electrochemical sensing and signal amplification within a single integrated device unit. However, given the organic semiconductor time-consuming doping process and their usual low field-effect mobility, OECTs are frequently considered low-end category devices. Toward high-performance OECTs, microtubular electrochemical devices based on strain-engineering are presented here by taking advantage of the exclusive shape features of self-curled nanomembranes. Such novel OECTs outperform the state-of-the-art organic liquid-gated transistors, reaching lower operating voltage, improved ion doping, and a signal amplification with a >104  intrinsic gain. The multipurpose OECT concept is validated with different electrolytes and distinct nanometer-thick molecular films, namely, phthalocyanine and thiophene derivatives. The OECTs are also applied as transducers to detect a biomarker related to neurological diseases, the neurotransmitter dopamine. The self-curled OECTs update the premises of electrochemical energy conversion in liquid-gated transistors, yielding a substantial performance improvement and new chemical sensing capabilities within picoliter sampling volumes.

Edge-driven nanomembrane-based vertical organic transistors showing a multi-sensing capability.

The effective utilization of vertical organic transistors in high current density applications demands further reduction of channel length (given by the thickness of the organic semiconducting layer and typically reported in the 100 nm range) along with the optimization of the source electrode structure. Here we present a viable solution by applying rolled-up metallic nanomembranes as the drain-electrode (which enables the incorporation of few nanometer-thick semiconductor layers) and by lithographically patterning the source-electrode. Our vertical organic transistors operate at ultra-low voltages and demonstrate high current densities (~0.5 A cm-2) that are found to depend directly on the number of source edges, provided the source perforation gap is wider than 250 nm. We anticipate that further optimization of device structure can yield higher current densities (~10 A cm-2). The use of rolled-up drain-electrode also enables sensing of humidity and light which highlights the potential of these devices to advance next-generation sensing technologies.

Ambipolar Resistive Switching in an Ultrathin Surface-Supported Metal-Organic Framework Vertical Heterojunction.

Memristors (MRs) are considered promising devices with the enormous potential to replace complementary metal-oxide-semiconductor (CMOS) technology, which approaches the scale limit. Efforts to fabricate MRs-based hybrid materials may result in suitable operating parameters coupled to high mechanical flexibility and low cost. Metal-organic frameworks (MOFs) arise as a favorable candidate to cover such demands. The step-by-step growth of MOFs structures on functionalized surfaces, called surface-supported metal-organic frameworks (SURMOFs), opens the possibility for designing new applications in strategic fields such as electronics, optoelectronics, and energy harvesting. However, considering the MRs architecture, the typical high porosity of these hybrid materials may lead to short-circuited devices easily. In this sense, here, it is reported for the first time the integration of SURMOF films in rolled-up scalable-functional devices. A freestanding metallic nanomembrane provides a robust and self-adjusted top mechanical contact on the SURMOF layer. The electrical characterization reveals an ambipolar resistive switching mediated by the humidity level with low-power consumption. The electronic properties are investigated with density functional theory (DFT) calculations. Furthermore, the device concept is versatile, compatible with the current parallelism demands of integration, and transcends the challenge in contacting SURMOF films for scalable-functional devices.

A Survey on Unmanned Surface Vehicles for Disaster Robotics: Main Challenges and Directions.

Disaster robotics has become a research area in its own right, with several reported cases of successful robot deployment in actual disaster scenarios. Most of these disaster deployments use aerial, ground, or underwater robotic platforms. However, the research involving autonomous boats or Unmanned Surface Vehicles (USVs) for Disaster Management (DM) is currently spread across several publications, with varying degrees of depth, and focusing on more than one unmanned vehicle-usually under the umbrella of Unmanned Marine Vessels (UMV). Therefore, the current importance of USVs for the DM process in its different phases is not clear. This paper presents the first comprehensive survey about the applications and roles of USVs for DM, as far as we know. This work demonstrates that there are few current deployments in disaster scenarios, with most of the research in the area focusing on the technological aspects of USV hardware and software, such as Guidance Navigation and Control, and not focusing on their actual importance for DM. Finally, to guide future research, this paper also summarizes our own contributions, the lessons learned, guidelines, and research gaps.

Low-Voltage, Flexible, and Self-Encapsulated Ultracompact Organic Thin-Film Transistors Based on Nanomembranes.

Organic thin-film transistors (OTFTs) are an ever-growing subject of research, powering recent technologies such as flexible and wearable electronics. Currently, many studies are being carried out to push forward the state-of-the-art OTFT technology to achieve characteristics that include high carrier mobility, low power consumption, flexibility, and the ability to operate under harsh conditions. Here, we tackle this task by proposing a novel OTFT architecture exploring the so-called rolled-up nanomembrane technology to fabricate low-voltage (<2 V), ultracompact OTFTs. As the OTFT gate electrode, we use strained nanomembranes, which allows all transistor components to be rolled-up and confined into a tubular-shaped tridimensional device structure with reduced footprint (ca. 90% of their planar counterpart), without any loss of electrical performance. Such an innovative architecture endows the OTFTs high mechanical flexibility (bending radius of <30 µm) and robustness-the devices can be reversibly deformed, withstanding more than 500 radial compression/decompression cycles. Additionally, the tubular device design possesses an inherent self-encapsulation characteristic that protects the OTFT active region from degradation by UV-light and hazardous vapors. The reported strategy is also shown to be compatible with different organic semiconductor materials. All of these characteristics contribute to further extending the potentialities of OTFTs, mainly toward rugged electronics.

A simple capacitive method to evaluate ethanol fuel samples.

Ethanol is a biofuel used worldwide. However, the presence of excessive water either during the distillation process or by fraudulent adulteration is a major concern in the use of ethanol fuel. High water levels may cause engine malfunction, in addition to being considered illegal. Here, we describe the development of a simple, fast and accurate platform based on nanostructured sensors to evaluate ethanol samples. The device fabrication is facile, based on standard microfabrication and thin-film deposition methods. The sensor operation relies on capacitance measurements employing a parallel plate capacitor containing a conformational aluminum oxide (Al2O3) thin layer (15 nm). The sensor operates over the full range water concentration, i.e., from approximately 0% to 100% vol. of water in ethanol, with water traces being detectable down to 0.5% vol. These characteristics make the proposed device unique with respect to other platforms. Finally, the good agreement between the sensor response and analyses performed by gas chromatography of ethanol biofuel endorses the accuracy of the proposed method. Due to the full operation range, the reported sensor has the technological potential for use as a point-of-care analytical tool at gas stations or in the chemical, pharmaceutical, and beverage industries, to mention a few.

Computational study of Th(4+) and Np(4+) hydration and hydrolysis of Th(4+) from first principles.

The aqueous solvation of Th and Np in the IV oxidation state was examined using cluster models generated by Monte Carlo simulations and density functional theory embedded within the COSMO continuum model to approximate the effect of bulk water. Our results suggest that the coordination number (CN) for both Th(IV) and NP(IV) should be 9, in accordance to some experimental and theoretical results from the literature. The structural values for average oxygen-metal distances are within 0.01 Å compared to experimental data, and also within the experimental error. The calculated ΔG Sol0 are in very good agreement with experimental reported values, with deviations at CN = 9 lower than 1% for both Th(IV) and Np(IV). The hydrolysis constants are also in very good agreement with experimental values. Finally, this [corrected] methodology has the advantage of using a GGA functional (BP86) that not only makes the calculations more affordable computationally than hybrid functional or ab initio molecular dynamics simulations (Car-Parrinello) calculations, but also opens the perspective to use resolution of identity (RI) calculations for more extended systems.

Hybrid organic/inorganic interfaces as reversible label-free platform for direct monitoring of biochemical interactions.

The combination of organic and inorganic materials to create hybrid nanostructures is an effective approach to develop label-free platforms for biosensing as well as to overcome eventual leakage current-related problems in capacitive sensors operating in liquid. In this work, we combine an ultra-thin high-k dielectric layer (Al2O3) with a nanostructured organic functional tail to create a platform capable of monitoring biospecific interactions directly in liquid at very low analyte concentrations. As a proof of concept, a reversible label-free glutathione-S-transferase (GST) biosensor is demonstrated. The sensor can quantify the GST enzyme concentration through its biospecific interaction with tripeptide reduced glutathione (GSH) bioreceptor directly immobilized on the dielectric surface. The enzymatic reaction is monitored by electrical impedance measurements, evaluating variations on the overall capacitance values according to the GST concentration. The biosensor surface can be easily regenerated, allowing the detection of GST with the very same device. The biosensor shows a linear response in the range of 200pmolL-1 to 2µmolL-1, the largest reported in the literature along with the lowest detectable GST concentration (200pmolL-1) for GST label-free sensors. Such a nanostructured hybrid organic-inorganic system represents a powerful tool for the monitoring of biochemical reactions, such as protein-protein interactions, for biosensing and biotechnological applications.

In situ marker-based assessment of leaf trait evolutionary potential in a marginal European beech population.

Evolutionary processes are expected to be crucial for the adaptation of natural populations to environmental changes. In particular, the capacity of rear edge populations to evolve in response to the species limiting conditions remains a major issue that requires to address their evolutionary potential. In situ quantitative genetic studies based on molecular markers offer the possibility to estimate evolutionary potentials manipulating neither the environment nor the individuals on which phenotypes are measured. The goal of this study was to estimate heritability and genetic correlations of a suite of leaf functional traits involved in climate adaptation for a natural population of the tree Fagus sylvatica, growing at the rear edge of the species range. Using two marker-based quantitative genetics approaches, we obtained consistent and significant estimates of heritability for leaf phenological (phenology of leaf flush), morphological (mass, area, ratio mass/area) and physiological (δ(13)C, nitrogen content) traits. Moreover, we found only one significant positive genetic correlation between leaf area and leaf mass, which likely reflected mechanical constraints. We conclude first that the studied population has considerable genetic diversity for important ecophysiological traits regarding drought adaptation and, second, that genetic correlations are not likely to impose strong genetic constraints to future population evolution. Our results bring important insights into the question of the capacity of rear edge populations to evolve.

Pathology of congenital Zika syndrome in Brazil: a case series

Zika virus is an arthropod-borne virus that is a member of the family Flaviviridae transmitted mainly by mosquitoes of the genus Aedes. Although usually asymptomatic, infection can result in a mild and self-limiting illness characterised by fever, rash, arthralgia, and conjunctivitis. An increase in the number of children born with microcephaly was noted in 2015 in regions of Brazil with high transmission of Zika virus. More recently, evidence has been accumulating supporting a link between Zika virus and microcephaly. Here, we describe findings from three fatal cases and two spontaneous abortions associated with Zika virus infection.

Disposition of irbesartan, an angiotensin II AT1-receptor antagonist, in mice, rats, rabbits, and macaques.

Metabolism and disposition of irbesartan, an angiotensin II AT(1) receptor antagonist, were investigated in mice, rats, rabbits, and macaques. In both rats and macaques, irbesartan was characterized by a rapid oral absorption, a large volume of distribution, a low plasma clearance, and a long terminal half-life. The oral bioavailability in macaques was notably higher than in rats. Irbesartan was highly protein bound in rats and macaques. A lower binding rate was found in mice and rabbits. In distribution studies performed in rats, mice, and rabbits, irbesartan was rapidly distributed into most organs and tissues including brain, intrauterine area, and milk. No retention of radioactivity in tissues other than liver and kidney was noted. Irbesartan was the main circulating compound in rats, rabbits, and macaques representing a maximum of 67, 68, and 80% of plasma radioactivity, respectively. The drug was metabolized mainly by glucuronidation (primarily on the tetrazole ring), hydroxylation, and additional oxidation. The overall pathways within the different species generated 18 metabolites identified from bile, urine, and feces samples. Irbesartan did not significantly induce or inhibit most of the isoenzymes commonly associated with drug metabolism in either rats or macaques after oral administration for 1 month. In most species irbesartan and its metabolites were mainly excreted in feces with more than 80% of a radioactive dose recovered within 24 or 48 h. Enterohepatic circulation was demonstrated in rats and macaques.

Disposition of tiludronate (Skelid) in animals.

The disposition of tiludronate in mouse, rat, rabbit, dog and monkey has been studied after oral and intravenous doses. Like other bisphosphonates, tiludronate was characterized by poor absorption from the gastrointestinal tract. Peak plasma concentrations appeared shortly (0.5-1 h) after dosing, except for the baboon (4.5 h). Food intake highly impaired intestinal absorption The affinity of tiludronate for bone and the slow release from this deep compartment could account for the large volume of distribution and the low plasma clearance found in all species. Tiludronate has low affinity for red blood cells and binds moderately to serum proteins, mainly to serum albumin. Calcified tissues appeared to be the main target for deposition. Distribution into bone was not homogenous, with higher levels in the trabecular bone than in the corticol part of the long bones. The uptake of tiludronate into bone was unequivocally less in the older animal. No metabolism occurred in the tested animal species. The major route of elimination of the absorbed drug is urine. Preclinical observations made with tiludronate, like with other bisphosphonates, were predictive of results obtained in clinical investigation.

Disposition of minaprine in animals and in human extensive and limited debrisoquine hydroxylators.

1. The disposition of 14C-minaprine was studied after oral administration of 5 and 20 mg/kg to rats, dogs and macaques, and of 200 mg to human volunteers with a genetic status of either limited or extensive hydroxylation of debrisoquine. 2. The drug was readily absorbed and a large proportion of the administered radioactivity was excreted within 48 h. The total excretion over 5 days ranged from 83% in monkeys to almost 100% in human with a status of extensive hydroxylators. 3. In the two limited hydroxylators Cmax values of total radioactivity in plasma were 4.6 and 3.7 mg equiv/l respectively. Those in the two extensive hydroxylators were 1.9 and 1.6 respectively. The highest value in the animal species was 8.1 in rats at a dose of 20 mg/kg. Plasma Cmax values of minaprine were 4.0 and 1.4 mg/l in limited hydroxylators and 0.35 and 0.23 mg/l in extensive ones. The highest value in the animal species was 2.7 mg/l in dogs treated with 20 mg/kg. 4. In rats and dogs, the ratios of the plasma AUC values for 20 mg/5 mg doses were close to those of the ratios of the doses administered, whereas in the macaque a slower clearance of radioactivity occurred with the higher dose (t 1/2 beta 5.5 h at 5 mg/kg dose versus 25.7 h at 20 mg/kg dose). 5. Marked species differences were observed in the metabolic pathways. The dog and limited hydroxylators showed higher levels of minaprine and its N-oxide (M4) whereas p-hydroxy-minaprine (M3) prevailed in monkey, rat and extensive hydroxylators. 6. In dogs only, seizures appeared within 10-15 min after dosage with minaprine at 20 mg/kg, when the concentrations of minaprine in erythrocytes (6.9 mg/l) and of M4 in plasma (0.40 mg/l) and erythrocytes (0.25 mg/l), were high. 7. The measurements and clinical observations indicate that onset of an adverse behavioural response in humans is unlikely at the dose of 200 mg.

Metabolism of minaprine in human and animal hepatocytes and liver microsomes--prediction of metabolism in vivo.

1. The metabolism of minaprine and its major metabolite p-hydroxyminaprine were studied using hepatocytes and liver microsomes from different species. Metabolism of this drug in vitro was then compared with in vivo data already published. 2. Our results showed that the major metabolic route (4-hydroxylation of the aromatic ring) is the same in the two experimental systems. Other in vivo biotransformation pathways (i.e. N-oxidation, reductive ring cleavage, N-dealkylation, oxidation) were also confirmed in hepatocytes. 3. Similar inter-species variability was observed both in vitro and in vivo. The present study has led to the same conclusion as previous in vivo metabolic investigations, namely, that metabolism in the dog quantitatively differs from that observed in other animal species. 4. These results clearly demonstrate that in vitro models (i.e. isolated hepatocytes and liver microsomes) are powerful tools in predicting the metabolic pathways of a drug in man and animal species.