Reversible Changes Research Articles

Daily singing of adult songbirds functions to maintain song performance independently of auditory feedback and age

Many songbirds learn to produce songs through vocal practice in early life and continue to sing daily throughout their lifetime. While it is well-known that adult songbirds sing as part of their mating rituals, the functions of singing behavior outside of reproductive contexts remain unclear. Here, we investigated this issue in adult male zebra finches by suppressing their daily singing for two weeks and examining the effects on song performance. We found that singing suppression decreased the pitch, amplitude, and duration of songs, and that those song features substantially recovered through subsequent free singing. These reversible song changes were not dependent on auditory feedback or the age of the birds, contrasting with the adult song plasticity that has been reported previously. These results demonstrate that adult song structure is not stable without daily singing, and suggest that adult songbirds maintain song performance by preventing song changes through physical act of daily singing throughout their life. Such daily singing likely functions as vocal training to maintain the song production system in optimal conditions for song performance in reproductive contexts, similar to how human singers and athletes practice daily to maintain their performance.

Transcriptomic analysis of N-terminal mutated Trypanosoma cruzi UBP1 knockdown underlines the importance of this RNA-binding protein in parasite development.

During its life cycle, the human pathogen Trypanosoma cruzi must quickly adapt to different environments, in which the variation in the gene expression of the regulatory U-rich RNA-binding protein 1 (TcUBP1) plays a crucial role. We have previously demonstrated that the overexpression of TcUBP1 in insect-dwelling epimastigotes orchestrates an RNA regulon to promote differentiation to infective forms. In an attempt to generate TcUBP1 knockout parasites by using CRISPR-Cas9 technology, in the present study, we obtained a variant transcript that encodes a protein with 95% overall identity and a modified N-terminal sequence. The expression of this mutant protein, named TcUBP1mut, was notably reduced compared to that of the endogenous form found in normal cells. TcUBP1mut-knockdown epimastigotes exhibited normal growth and differentiation into infective metacyclic trypomastigotes and were capable of infecting mammalian cells. We analyzed the RNA-Seq expression profiles of these parasites and identified 276 up- and 426 downregulated genes with respect to the wildtype control sample. RNA-Seq comparison across distinct developmental stages revealed that the transcriptomic profile of these TcUBP1mut-knockdown epimastigotes significantly differs not only from that of epimastigotes in the stationary phase but also from the gene expression landscape characteristic of infective forms. This is both contrary to and consistent with the results of our recent study involving TcUBP1-overexpressing cells. Together, our findings demonstrate that the genes exhibiting opposite changes under overexpression and knockdown conditions unveil key mRNA targets regulated by TcUBP1. These mostly encompass transcripts that encode for trypomastigote-specific surface glycoproteins and ribosomal proteins, supporting a role for TcUBP1 in determining the molecular characteristics of the infective stage.

Numerical Calculation of Gas–Liquid Two-Phase Flow in Tesla Valve

In this paper, the gas–liquid two-phase flow within a Tesla valve under zero-gravity conditions is numerically studied. Based on the VOF model and the inlet two-phase separation method, the forward and reverse flow patterns and pressure drop changes in a Tesla valve at different inlet velocities were analyzed. At an inlet velocity of 0.1–0.2 m/s, the flow pattern was slug flow, the bubbles were evenly distributed in different positions in the Tesla valve, and the velocity difference between the main pipe and the arc branch pipe was small. When the inlet velocity was 0.4 m/s, the main flow pattern was annular flow, and there was a phenomenon of gas–liquid phase separation through different flow channels, which was related to centrifugal force. At an inlet velocity of 0.6–0.8 m/s, bubbly flow and slug flow coexisted, which was related to the uneven velocity. In the study range, the difference in the forward and reverse pressure drops of two-phase flow was smaller than that of single-phase flow, and the two-phase diodicity decreased first and then increased with the change in inlet velocity, reaching minimum values of 0.78 at 0.2 m/s and 1.44 at 0.8 m/s.

Effects of structural remodelling on gill physiology.

The complex relationships between the structure and function of fish gills have been of interest to comparative physiologists for many years. Morphological plasticity of the gill provides a dynamic mechanism to reversibly alter its structure in response to changes in the conditions experienced by the fish. The best known example of gill remodelling is the growth or retraction of cell masses between the lamellae, a rapid process that alters the lamellar surface area that is exposed to the water (i.e. the functional lamellar surface area). Decreases in environmental O2 availability and/or increases in metabolic O2 demand stimulate uncovering of the lamellae, presumably to increase the capacity for O2 uptake. This review addresses four questions about gill remodelling: (1) what types of reversible morphological changes occur; (2) how do these changes affect physiological function from the gill to the whole animal; (3) what factors regulate reversible gill plasticity; and (4) is remodelling phylogenetically widespread among fishes? We address these questions by surveying the current state of knowledge of gill remodelling in fishes, with a focus on identifying gaps in our understanding that future research should consider.

Reversible Polarity Control in 2D MoTe2 Field‐Effect Transistors for Complementary Logic Gate Applications

AbstractPrecise control over polarity in field‐effect transistors (FETs) plays a pivotal role in the design and construction of complementary metal–oxide–semiconductor (CMOS) logic circuits. In particular, achieving such precise polarity control in 2D semiconductors is crucial for the further development of advanced electronic applications beyond unit devices. This paper presents a systematic investigation on the reversible transition of carrier types in a 2D MoTe2 semiconductor under different annealing atmospheres. Photoemission spectroscopy and density functional theory (DFT) calculations demonstrate that annealing processes in vacuum and in ambient air induce a modification in the density of states, resulting in alterations in p‐type or n‐type characteristics. These reversible changes are attributed to the physisorption and elimination of oxygen on the surface of MoTe2. Furthermore, it is found that the device geometry affects the polarity of the transistor. By strategically manipulating both the annealing conditions and the geometric configuration, the n‐ and p‐type unipolar characteristics of MoTe2 FETs are successfully modulated and ultimately demonstrating that the functionality of not only a complementary inverter with a high voltage gain of ≈20, but also more complex logic circuits of NAND and NOR gates.

Emerging Thermochromic Perovskite Materials: Insights into Fundamentals, Recent Advances and Applications

AbstractThermochromic perovskite materials exhibit reversible color changes in response to external thermal stimuli. Recently recognized as promising candidates, significant efforts are dedicated to developing these materials with tunable properties, rapid response, and effective light modulation. This review demonstrates recent advances in fabrication methods, mechanism investigation, solar modulation performance, and diverse applications of perovskite thermochromic materials. Thin films and single crystals are addressed separately, with a focus on achieving high‐quality and stable thermochromic perovskite materials across different dimensional architectures. Furthermore, the article outlines current challenges and provides forward‐looking perspectives, aiming to foster future innovative research and widespread application in smart windows, switchable photovoltaic devices, photo/thermal detectors, and anti‐counterfeiting technologies.

Programmable, Self-Healable, and Photochromic Liquid Crystal Elastomers Based on Dynamic Hindered Urea Bonds for Biomimetic Flowers.

Recently, researchers have been exploring the use of dynamic covalent bonds (DCBs) in the construction of exchangeable liquid crystal elastomers (LCEs) for biomimetic actuators and devices. However, a significant challenge remains in achieving LCEs with both excellent dynamic properties and superior mechanical strength and stability. In this study, a diacrylate-functionalized monomer containing dynamic hindered urea bonds (DA-HUB) is employed to prepare exchangeable LCEs through a self-catalytic Michael addition reaction. By incorporating DA-HUB, the LCE system benefits from DCBs and hydrogen bonding, leading to materials with high mechanical strength and a range of dynamic properties such as programmability, self-healing, and recyclability. Leveraging these characteristics, bilayer LCE actuators with controlled reversible thermal deformation and outstanding dimensional stability are successfully fabricated using a simple welding method. Moreover, a biomimetic triangular plum, inspired by the blooming of flowers, is created to showcase reversible color and shape changes triggered by light and heat. This innovative approach opens new possibilities for the development of biomimetic and smart actuators and devices with multiple functionalities.

Synthesis, optical properties, and dual‐color halochromic fluorescence of novel π‐conjugated polymers bearing coumarin unit in the main chain

AbstractA series of novel π‐conjugated polymers bearing alternating coumarin and phenylene units in the main chain backbone was synthesized via Sonogashira coupling reaction. The red‐shifts in the absorption maxima of the polymers indicate the expansion of π‐conjugated system in the polymer main chains. These polymers exhibited strong green fluorescence in organic solvents. Clearly perceptible dual‐color halochromic fluorescence was confirmed for the polymers by the significantly reversible changes of emission color from green to blue during alkalization and acidification processes. The lactone ring opening and closing property in the coumarin molecule functioned as a controllable switch, broadening the applications of the coumarin‐based π‐conjugated polymers as acid–base responsive fluorescence materials.

Bayesian networks for Risk Assessment and postoperative deficit prediction in intraoperative neurophysiology for brain surgery

Bayesian networks for Risk Assessment and postoperative deficit prediction in intraoperative neurophysiology for brain surgery

Magnolol ameliorates fumonisin B1-induced oxidative damage and lipid metabolism dysfunction in astrocyte-like C6 cells

The neurotoxicity of fumonisin B1 (FB1), a commonly detected mycotoxin in crops and the environment, has attracted considerable attention in recent years. However, no effective method for eliminating FB1 completely exists due to the thermal stability and water solubility of this mycotoxin. Magnolol (MAG) is a neolignane with antioxidative and neuroprotective effects. It has been applied in neurotoxicity treatment. However, the application of MAG to attenuate FB1-induced toxicity has not been reported. This study explored the protective mechanism of MAG against FB1-induced damage in C6 cells through antioxidant and lipid metabolism modulation. Results showed that exposure to 15 μM FB1 caused oxidative stress by changing the levels of malondialdehyde, reactive oxygen species, total superoxide dismutase, catalase, and total glutathione. These changes were reversed by MAG addition, especially at the concentration of 80 μM. The protective effects of MAG were further confirmed by the reduction in the phosphorylation levels of proteins in the MAPK signaling pathway. Lipidomics analysis identified 263 lipids, which belong to 24 lipid classes. Among all of the identified lipids, triglycerides (TGs), diglycerides (DGs), phosphatidylcholines (PCs), wax monoesters (WEs), Cers, and phosphatidylethanolamines (PEs) were major categories. Moreover, nine categories of lipids showed the opposite change trend in the FB1 exposure and MAG 80 groups. A further investigation of the 34 co-occurring differential lipids with remarkable changes (P value < 0.05 and VIP value > 1) in the control, FB1 exposure, and MAG 80 groups was performed. Therein, nine lipids (PCs, LPCs, and SM) were screened out as potential biomarkers to reveal the cytoprotective effects of MAG. This work is the first to investigate the rescue mechanism of MAG in FB1-induced cytotoxicity. The obtained results may expand the application of MAG to alleviate the toxicity of mycotoxins.

Simulated lunar microgravity transiently arrests growth and induces osteocyte-chondrocyte lineage differentiation in human Wharton’s jelly stem cells

Human Wharton’s jelly stem cells (hWJSCs) are multipotent stem cells that are extensively employed in biotechnology applications. However, the impact of simulated lunar microgravity (sμG) on the growth, differentiation, and viability of this cell population is incompletely characterized. We aimed to determine whether acute (72 h) exposure to sμG elicited changes in growth and lineage differentiation in hWJSCs and if putative changes were maintained once exposure to terrestrial gravity (1.0 G) was restored. hWJSCs were cultured under standard 1.0 G conditions prior to being passaged and cultured under sμG (0.16 G) using a random positioning machine. Relative to control, hWJSCs cultured under sμG exhibited marked reductions in growth but not viability. Cell population expression of characteristic stemness markers (CD 73, 90, 105) was significantly reduced under sμG conditions. hWJSCs had 308 significantly upregulated and 328 significantly downregulated genes when compared to 1.0 G culture conditions. Key markers of cell replication, including MKI67, were inhibited. Significant upregulation of osteocyte–chondrocyte lineage markers, including SERPINI1, MSX2, TFPI2, BMP6, COMP, TMEM119, LUM, HGF, CHI3L1 and SPP1, and downregulation of cell fate regulators, including DNMT1 and EZH2, were detected in sμG-exposed hWJSCs. When returned to 1.0 G for 3 days, sμG-exposed hWJSCs had accelerated growth, and expression of stemness markers increased, approaching normal (i.e. 95%) levels. Our data support earlier findings that acute sμG significantly reduces the cell division potential of hWJSCs and suggest that acute sμG-exposure induces reversible changes in cell growth accompanied by osteocyte–chondrocyte changes in lineage differentiation.

A Gd-doped ceria/TiOx nanocomposite as the active layer in a three terminal electrochemical resistivity switch.

Coupling between an electrochemical reaction and a functional material property has been termed electro-chemo-X, or EC-X, where X can refer to mechanical, optical, magnetic or thermal properties. Recently, our group has demonstrated a two-terminal electro-chemo-mechanical (ECM) membrane actuator operating under ambient conditions and containing a Ce0.8Gd0.2O1.9 solid electrolyte layer sandwiched between two Gd-doped ceria/TiOx nanocomposite thin films. Reducing one nanocomposite film while oxidizing the other was observed to produce reversible volume change thereby driving membrane actuator operation. Here, we use the same electrolyte and nanocomposite layer pair (the upper one as the ion reservoir and the lower, as the active layer) to further explore the EC-X effect. We demonstrate the suitability of the nanocomposite for a three-terminal, thin film-based resistivity switch. We find that application of ±6 V (<60 kV/cm) bias to the gate terminal for two hours under ambient conditions changes the nanocomposite conductivity in the channel between the source and drain by at least 40%. When the bias is negative, the active layer remains in a more highly conductive state for approximately twenty-four hours. Impedance spectroscopy and cyclic voltammetry reveal oxygen ion migration taking place between the active layer and the reservoir. X-ray photoelectron spectroscopy indicates that, in the absence of negative gate bias, thermal oxidation of Ce+3 - > Ce+4 is similarly effective in leading to increased nanocomposite conductivity, while reduction produces the opposite effect. With the expectation that the response time can be significantly shortened, the proposed resistivity switch may be suitable for future applications such as sensors, neuromorphic computing or spintronics.

New architecture based on Metal-Organic Frameworks and spin crossover complexes to detect volatile organic compounds.

We present here the encapsulation of a spin crossover complex C1 [FeII(L)] (L: 4-amino-, 2-(2-pyridinylmethylene)hydrazide) inside MOF-808(Zr), a chemically robust Metal-Organic Framework. The compound C1⊂MOF-808 retains its crystallinity as well as a partial porosity compared to pristine MOF and shows solvatochromism under Volatile Organic compounds (VOCs) sorption associated to a spin state change of the guest complex. More specifically, this compound shows an interesting reversible color change under formaldehyde and formic acid vapor sorption and can therefore be considered as a new kind of optical VOCs chemosensor, opening new doors for developing a broad range of VOCs optical sensors.

Reversible Cytotoxic Edema in Patients with COVID-19 Associated Encephalitis Presenting Status Epilepticus

Coronavirus disease 2019 (COVID-19) is a serious infectious disease with multisystem alteration including neurological complications. COVID-19 associated encephalitis is a potentially fatal viral infection of the brain. Diffusion-weighted images (DWI) are a useful evaluation modality of cytotoxic edema in patients with encephalitis. We report on the reversible DWI change in a patient with COVID-19 associated encephalitis, who had diffused cytotoxic edema in the affected temporal lobe and accompanied status epilepticus. Sequential imaging showed that the cytotoxic edema in DWI confirmed recovery to normal after 12 days in the presence of cortical edema in fluid-attenuated inversion recovery image after aggressive neurocritical management. Thus, prompt, proper management is indispensable during the acute period and DWI may be a valuable tool for reflecting the clinical course of COVID-19 associated encephalitis.

High energy-storage density and giant negative electrocaloric effect in PLZS antiferroelectric thick film ceramics prepared via the tape-casting process

Antiferroelectric materials are highly desired for high energy-storage density capacitors and electrocaloric refrigerator in the future due to their excellent energy storage properties and giant negative electrocaloric effect, which have attracted great attention in recent years. In the present work, a highly recoverable energy density (Wrec) and a large reversible adiabatic temperature change (ΔT) were obtained simultaneously in PLZS thick film ceramics (TFCs). A maximum Wrec of 9.84J·cm-3 with an efficiency of 85.2% at 440kV·cm-1, and a negative ΔT of -9.50 °C at 280kV·cm-1 were obtained. Moreover, the maximum value of electrocaloric strength of 0.98K·m·MV-1 was achieved for Pb0.97La0.02(Zr0.50Sn0.50)O3 TFCs. These results demonstrate that the PLZS TFCs can be applied potentially for high energy-storage density capacitors and refrigerators.

Crystal structure, Hirshfeld surface analysis and photophysical properties of disubstituted 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dianiline

Two independent molecules of the crystal structure of the title compound C18H14N4S were found to occupy the asymmetric unit of the space group. The flanking 4-anilines were not coplanar with the central benzothiadiazole, but they were twisted from the plane. In the crystal, two unique types of hydrogen bonds were found: i) one set between two NH2 of two molecules in the asymmetric unit and ii) another set between hydrogen atoms of the second aniline NH2 and the nitrogen atom of benzothiadiazole. The two-dimensional fingerprint plots along with the Hirshfeld surface confirmed the most important contributions for the crystal packing were C···H, H···H and N···H interactions. The compound was also solvatochromic with both its emission wavelength and quantum yield contingent on the solvent polarity. The fluorophore had a reversible oxidation. This was used to induce both a reversible color change from yellow to blue and emission off/on with an applied potential.

Reconfigurable intelligent surface and switchable electromagnetic interference shield based on dynamically adjustable composite film of cellulose nanofibers and VO2 nanoparticles

The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications.

West Syndrome due to ALG13 mutation presenting vigabatrin-associated reversible MRI signal changes and drug-induced dyskinesia

Heterozygous mutations in the asparagine-linked glycosylation 13 (ALG13) gene cause a rare genetic disorder that severely affects neurological development. Symptoms associated with ALG13 mutations include severe epilepsy and/or West syndrome (WS). Most cases reported in the literature describe typical characteristics of patients within whom de novo mutations have been identified. A 5-month-old girl with developmental delay and epileptic spasms, without dysmorphic features, is described. Electroencephalography (EEG) showed hypsarrhythmia, compatible with WS, but complementary examinations did not find an underlying etiology. Vigabatrin therapy was started, and then adrenocorticotropic hormone (ACTH) therapy was added. On follow-up, brain magnetic resonance imaging (MRI) revealed restricted diffusions compatible with vigabatrin-associated reversible MRI signal changes. As the spasms and hypsarrhythmia on EEG persisted, a second cycle of ACTH was performed, and then, the patient manifested a hyperkinetic movement, characteristic of drug-induced dyskinesia. Further investigation was carried out, and whole-exome sequencing revealed a de novo pathogenic variant in ALG13 gene. The current case report expands our knowledge of WS by considering a female patient with unspecific clinical features arising from an undefined subjacent etiology. This case also emphasizes the importance of a thorough work-up to determine the underlying genetic etiology and presents the challenges in the diagnostic investigation in clinical practice.

Expression and secretion of galectin-12 in the context of neutrophilic differentiation of human promyeloblastic HL-60 cells.

Galectin-12 is a tissue-specific galectin that has been largely defined by its role in the regulation of adipocyte differentiation and lipogenesis. This study aimed to evaluate the role of galectin-12 in the differentiation and polarization of neutrophils within a model of acute myeloid leukemia HL-60 cells. All-trans retinoic acid and dimethyl sulfoxide were used to induce differentiation of HL-60 cells which led to the generation of two phenotypes of neutrophil-like cells with opposite changes in galectin-12 gene (LGALS12) expression and different functional responses to N-formyl- l-methionyl- l-leucyl- l-phenylalanine. These phenotypes showed significant differences of differentially expressed genes on a global scale based on bioinformatics analysis of available Gene Expression Omnibus (GEO) data sets. We also demonstrated that HL-60 cells could secrete and accumulate galectin-12 in cell culture medium under normal growth conditions. This secretion was found to be entirely inhibited upon neutrophilic differentiation and was accompanied by an increase in intracellular lipid droplet content and significant enrichment of 22 lipid gene ontology terms related to lipid metabolism in differentiated cells. These findings suggest that galectin-12 could serve as a marker of neutrophilic plasticity or polarization into different phenotypes and that galectin-12 secretion may be influenced by lipid droplet biogenesis.

Exploring the Effects of the Photochromic Response and Crystallization on the Local Structure of Noncrystalline Niobium Oxide.

Niobium oxide (Nb2O5) is a versatile semiconductor material with photochromic properties. This study investigates the local structure of noncrystalline, short-range-ordered niobium oxide synthesized via a sol-gel method. X-ray atomic pair distribution function analysis unravels the structural arrangements within the noncrystalline materials at a local scale. In the following, in situ scattering and diffraction experiments elucidate the heat-induced structure transformation of the amorphous material into crystalline TT-Nb2O5 at 550 °C. In addition, the effect of photocatalytic conditions on the structure of the material was investigated by exposing the short-range-ordered and crystalline materials to ultraviolet light, resulting in a reversible color change from white to dark brown or blue. This photochromic response is due to the reversible elongation of the nearest Nb-O neighbors, as shown by local structure analysis based on in situ PDF analyses. Optical band gap calculations based on the ultraviolet-visible spectra collected for both the short-range-ordered and crystalline materials show that the band gap values reduced for the darkened materials return to their initial state after bleaching. Furthermore, electron energy loss spectroscopy reveals the reduction of Nb5+ to Nb4+ centers as a persistent effect. The study establishes a correlation between the band gap and the structure of niobium oxide, providing insights into the structure-performance relation at the atomic level.