Heterostructures formed by ultrathin borocarbonitride (BCN) layers grown on TiO2 nanoribbons were investigated as photoanodes for photoelectrochemical water splitting. TiO2 nanoribbons were obtained ...by thermal oxidation of TiS3 samples. Then, BCN layers were successfully grown by plasma enhanced chemical vapour deposition. The structure and the chemical composition of the starting TiS3, the TiO2 nanoribbons and the TiO2-BCN heterostructures were investigated by Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. Diffuse reflectance measurements showed a change in the gap from 0.94 eV (TiS3) to 3.3 eV (TiO2) after the thermal annealing of the starting material. Morphological characterizations, such as scanning electron microscopy and optical microscopy, show that the morphology of the samples was not affected by the change in the structure and composition. The obtained TiO2-BCN heterostructures were measured in a photoelectrochemical cell, showing an enhanced density of current under dark conditions and higher photocurrents when compared with TiO2. Finally, using electrochemical impedance spectroscopy, the flat band potential was determined to be equal in both TiO2 and TiO2-BCN samples, whereas the product of the dielectric constant and the density of donors was higher for TiO2-BCN.
Abstract
Layered metal chalcogenide materials are exceptionally appealing in optoelectronic devices thanks to their extraordinary optical properties. Recently, their application as flexible and ...wearable photodetectors have received a lot of attention. Herein, broadband and high-performance paper-based PDs were established in a very facile and inexpensive method by rubbing molybdenum disulfide and titanium trisulfide crystals on papers. Transferred layers were characterized by SEM, EDX mapping, and Raman analyses, and their optoelectronic properties were evaluated in a wavelength range of 405–810 nm. Although the highest and lowest photoresponsivities were respectively measured for TiS
3
(1.50 mA/W) and MoS
2
(1.13 μA/W) PDs, the TiS
3
–MoS
2
heterostructure not only had a significant photoresponsivity but also showed the highest on/off ratio (1.82) and fast response time (0.96 s) compared with two other PDs. This advantage is due to the band offset formation at the heterojunction, which efficiently separates the photogenerated electron–hole pairs within the heterostructure. Numerical simulation of the introduced PDs also confirmed the superiority of TiS
3
–MoS
2
heterostructure over the other two PDs and exhibited a good agreement with the experimental results. Finally, MoS
2
PD demonstrated very high flexibility under applied strain, but TiS
3
based PDs suffered from its fragility and experience a remarkable drain current reduction at strain larger than ± 0.33%. However, at lower strains, all PDs displayed acceptable performances.
Control over the morphology of TiS3 is demonstrated by synthesizing 1D nanoribbons and 2D nanosheets. The nanosheets can be exfoliated down to a single layer. Through extensive characterization of ...the two morphologies, differences in the electronic properties are found and attributed to a higher density of sulphur vacancies in nanosheets, which, according to density functional theory calculations, leads to an n‐type doping.
Animals can learn about the value of resources and predation risk by exploring novel environments or exploring novel stimuli in their regular environments. Still, there is a disconnect in the way ...that exploration has been defined and measured; exploration is defined in terms of information acquisition, while measured in terms of movement speed and diversity of contacted items in a novel environment. If exploration is indeed a measurement of information gathering, fast explorers should seek to reduce uncertainty about their environment more than slow explorers. Exploration speed has also been linked to behavioral plasticity, where fast explorers move fast but collect less detailed information, thereby forming routines and expressing less plasticity than slow explorers. We test these two hypotheses by comparing exploration in a novel environment to individuals' attraction to novelty and behavioral plasticity. Our results support the view that exploration is a measurement of information‐gathering tendencies as fast explorers were more likely to collect novel information, which should reduce uncertainty further than sampling familiar information sources, compared with slower explorers. Furthermore, faster explorers switched to sampling novel information more quickly than slow explorers when the value of the familiar option decreased, opposing the widely held view that faster explorers present more routine‐like behavior. By providing familiar and novel foraging options in close spatial contiguity, we demonstrate an attraction to novelty in faster explorers that cannot be confounded by activity rate, thereby suggesting that these individuals seek to reduce uncertainty. In conclusion, our results support the biological validity of the term “exploration” through its association with information gathering.
Detection of circulating cell-free DNA (cfDNA) requires multiple processes, including plasma separation, cfDNA isolation, and high-sensitivity detection. However, implementing such processes in a ...single system in a simple and effective manner is nontrivial. Here, we present a fluidic system for the isolation and detection of cfDNA from whole blood performed in a fully automated and effective manner. The system utilizes vertically mobile top and rotational bottom parts with multiple disposable chambers for sequential processes. The key components for plasma filtration are a sedimentation chamber that enables the dextran-enhanced sedimentation of red blood cells and a plunger chamber with a porous filter and a check valve. cfDNA in the plasma is captured by silica-coated magnetic beads in the plunger chamber, washed via the motion of the top and bottom parts, and then detected by real-time on-chip polymerase chain reaction. We vary several parameters, including the plunger speed, dextran concentration, and hematocrit concentration, to optimize the time and efficiency of the assay. The total assay time is 1.5 h with a detection limit of 42 ag/mL for a sample volume of 1.5 mL. Plasma and cfDNA recoveries are 53% and 28%, respectively. Our system is a useful tool for all-in-one assays in liquid biopsies of cancers and other diseases detectable by cfDNA.
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•A fluidic system isolates and detects cfDNA from whole blood in a fully automated and effective manner.•Dextran-enhanced sedimentation of red blood cells and plasma filtration with a porous filter and a check valve are used.•The total assay time is 1.5 h with a detection limit of 42 ag/mL for a sample volume of 1.5 mL.
Neophobia, defined as the fear of novelty, can be exhibited when individuals encounter unfamiliar stimuli in their environment. Neophobia has been shown to both increase and decrease when individuals ...are with conspecifics. An increase in latency to contact new objects can be explained by the negotiation hypothesis, which proposes that individuals in groups will negotiate who will approach novelty first, thereby delaying the first contact. This negotiation process could co‐occur with and mask a potential effect of risk dilution, where individuals in groups should approach novel objects faster due to lower perceived risk in a social than non‐social context. Here, we aimed to test the risk dilution hypothesis using an experimental set‐up that precluded negotiation among group members by physically separating dyads during social trials. We presented zebra finches (Taeniopygia guttata) with different novel objects in both social and non‐social contexts. We also repeated the presentation of each object to investigate, for the first time to our knowledge, the effect of social context on the change in neophobia over repeated encounters (i.e., habituation). We found that social context increased the latency to approach a novel object upon first presentation of objects (i.e., increased neophobia), but these latencies decreased faster over repeated presentations of the objects (i.e., faster habituation) compared to the non‐social context. These results do not provide support for the risk dilution hypothesis regarding first encounters with objects (neophobia) but seem to support it over repeated object presentations (habituation). This suggests that the effect of social context is different on neophobia and habituation, possibly because they recruit different cognitive mechanisms. Future studies should investigate the impact of ecological and social conditions on decision‐making upon first versus subsequent encounters with a novel object in social animals, as both processes can impact fitness costs and benefits of novelty responses.
In the last decades, a broad family of hydrides have attracted attention as prospective hydrogen storage materials of very high gravimetric and volumetric capacity, fast H2‐sorption kinetics, ...environmental friendliness and economical affordability. However, constraints due to their high activation energies of the different H2‐sorption steps and the Gibbs energy of their reaction with H2 has led to the need of high thermal energy to drive H2 uptake and release. High heat leads to significant degradation effects (recrystallization, phase segregation, nanoparticles agglomeration…) of the hydrides. In this context, this short review aims to summarize alternative non‐thermal methods and non‐straightforward thermally driven methods to overcome the previous constraints. The phenomenology lying behind these methods, i. e. tribological activation, sonication, and electromagnetic radiation, and the effect of these processes on hydrogen sorption properties of hydrides are described. These non‐usual approaches could boost the capability of the next generation of solid‐hydride materials for hydrogen conversion in energy sector, in mobile devices and as hydrogen reservoirs.
Unconventional approaches? The influence of rather uncommon energy sources (illustrated in the picture) on H2‐sorption properties of hydrides are described and analyzed in this minireview.
The aryl hydrocarbon receptor (AhR) is a ligand‐activated transcription factor, largely known for its role in xenobiotic metabolism and detoxification as well as its crucial role as a regulator of ...inflammation. Here, we have compared a cohort wild‐type and AhR‐null mice along aging to study the relationship between this receptor and age‐associated inflammation, termed as “inflammaging,” both at a systemic and the CNS level. Our results show that AhR deficiency is associated with a premature aged phenotype, characterized by early inflammaging, as shown by an increase in plasma cytokines levels. The absence of AhR also promotes the appearance of brain aging anatomic features, such as the loss of the white matter integrity. In addition, AhR–/– mice present an earlier spatial memory impairment and an enhanced astrogliosis in the hippocampus when compared with their age‐matched AhR+/+ controls. Importantly, we have found that AhR protein levels decrease with age in this brain structure, strongly suggesting a link between AhR and aging.—Bravo‐Ferrer, I., Cuartero, M. I., Medina, V., Ahedo‐Quero, D., Peña‐Martínez, C., Pérez‐Ruíz, A., Fernández‐Valle, M. E., Hernández‐Sánchez, C., Fernández‐Salguero, P. M., Lizasoain, I., Moro, M. A. Lack of the aryl hydrocarbon receptor accelerates aging in mice. FASEB J. 33, 12644–12654 (2019). www.fasebj.org
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