Time-dependent Transformation Research Articles

Bioaccumulation, biodistribution, and transformation of polyvinylpyrrolidone-coated silver nanoparticles in edible seaweeds

Seaweeds are recognised as a potential eco-friendly food source. However, some species have shown the capacity to bioaccumulate many substances of diverse nature, such as inorganic nanoparticles (NPs), which may have potentially harmful effects on them. Among these NPs, silver nanoparticles (AgNPs) have been used to enhance the antifungal and antibacterial properties of the final consumer products, such as textiles and food packages. Their potential release into the aquatic environment raises significant concern, increasing the probability of interaction with aquatic biota, such as macroalgae.In this work, we investigated the differences in bioaccumulation, biodistribution, and transformation of NPs as a function of seaweed species. We selected polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) as model NP since they remain colloidally stable in seawater, focusing the study only on single particles and not on aggregates. The study was conducted on two different seaweed species with high commercial interest and value as human food: the red seaweed Palmaria palmata and the green seaweed Ulva fenestrata. Single-particle inductively coupled plasma mass spectroscopy (spICP-MS) analysis showed high and similar bioaccumulation of PVP-AgNPs in both seaweeds, in the range of 109 NPs/g of seaweed. However, electron microscopy with energy-dispersive X-ray analysis demonstrated that their time-dependent distribution and transformation in the algal tissue, mainly dissolution and formation of sulfur-rich corona and/or sulfidation, highly depended on the seaweed type.These results indicate that special attention should be given to the presence and transformation of AgNPs in seaweeds intended for human consumption. Not only the dissolution degree but also the speciation of these NPs could heavily impact their bioaccessibility, bioavailability, biodistribution, and toxicity to humans after ingestion.

Copper-catalyzed time-dependent easy transformation of aryl/heteroaryl aldehyde into cyano and amide derivatives using ammonium acetate/iodine

Copper-catalyzed time-dependent easy transformation of aryl/heteroaryl aldehyde into cyano and amide derivatives using ammonium acetate/iodine

Classical and quantum thermodynamics described as a system-bath model: The dimensionless minimum work principle.

We formulate a thermodynamic theory applicable to both classical and quantum systems. These systems are depicted as thermodynamic system-bath models capable of handling isothermal, isentropic, thermostatic, and entropic processes. Our approach is based on the use of a dimensionless thermodynamic potential expressed as a function of the intensive and extensive thermodynamic variables. Using the principles of dimensionless minimum work and dimensionless maximum entropy derived from quasi-static changes of external perturbations and temperature, we obtain the Massieu-Planck potentials as entropic potentials and the Helmholtz-Gibbs potentials as free energy. These potentials can be interconverted through time-dependent Legendre transformations. Our results are verified numerically for an anharmonic Brownian system described in phase space using the low-temperature quantum Fokker-Planck equations in the quantum case and the Kramers equation in the classical case, both developed for the thermodynamic system-bath model. Thus, we clarify the conditions for thermodynamics to be valid even for small systems described by Hamiltonians and establish a basis for extending thermodynamics to non-equilibrium conditions.

Non-relativistic M2-branes and the AdS/CFT correspondence

A non-relativistic limit of the AdS/CFT correspondence is studied in the context of M2-branes. On the field theory side this corresponds to a near-BPS limit of ABJM that localises onto solutions of Hitchin’s equations. It is shown that the symmetries of the theory include an infinite-dimensional enhancement of the spatial symmetry algebra corresponding to time-dependent holomorphic transformations. Taking the limit of the gravitational dual splits the geometry into three ‘large’ directions and eight ‘small’ directions and corresponds to the Membrane-Newton-Cartan limit of eleven-dimensional supergravity. This has the effect of reducing the AdS4 factor to an AdS2 factor for the near-horizon limit of the M2-brane metric. Evidence is presented that the duality is maintained after the limit.

An acid-chromic luminescent lanthanide metallogel for time-dependent information encryption and anti-counterfeiting.

Luminescent materials with dynamic color transformation demonstrate significant potential in advanced information encryption and anti-counterfeiting. In this study, we designed multi-color luminescent lanthanide metallogels featuring time-dependent color transformation. These materials are based on Förster resonance energy transfer (FRET) platforms, facilitating cascade energy transfer from the ligand 4,4',4''-[1,3,5-benzenetriyltris (carbonylimino)]trisbenzoic acid (H3L) to Tb3+ ions and subsequently to Sulforhodamine 101. The emission color of the gels can be readily adjusted by the introduction of HCl, transitioning from initial green, yellow, light red, and red hues to blue, violet, pink, and deep red, respectively. Importantly, the color change in these gels is time-dependent, controlled by the hydrolysis time of glucono-δ-lactone, which modulates the luminescence intensity of H3L, Tb3+, and Sulforhodamine 101. Exploiting these characteristics, we developed methods for information encryption utilizing 3D color codes and anti-counterfeiting flower patterns. These patterns undergo time-dependent transformations, generating a series of 3D codes and flower patterns that can only be recognized in a predetermined manner. These findings highlight the promising application of lanthanide metallogels in advanced information protection strategies.

Modular photoorigami-based 4D manufacturing of vascular junction elements.

Four-dimensional (4D) printing, combining three-dimensional (3D) printing with time-dependent stimuli-responsive shape transformation, eliminates the limitations of the conventional 3D printing technique for the fabrication of complex hollow constructs. However, existing 4D printing techniques have limitations in terms of the shapes that can be created using a single shape-changing object. In this paper, we report an advanced 4D fabrication approach for vascular junctions, particularly T-junctions, using the 4D printing technique based on coordinated sequential folding of two or more specially designed shape-changing elements. In our approach, the T-junction is split into two components, and each component is 4D printed using different synthesized shape memory polyurethanes and their nanohybrids, which have been synthesized with varying hard segment contents and by incorporating different weight percentages of photo-responsive copper sulfide-polyvinyl pyrrolidone nanoparticles. The formation of a T-junction is demonstrated by assigning different shape memory behaviors to each component of the T-junction. A cell culture study with human umbilical vein endothelial cells reveals that the cells proliferate over time, and almost 90% of cells remain viable on day 7. Finally, the formation of the T-junction in the presence of near-infrared light has been demonstrated after seeding the endothelial cells on the programmed flat surface of the two components and fluorescence microscopy at day 3 and 7 reveals that the cells adhered well and continue to proliferate over time. Hence, the proposed alternative approach has huge potential and can be used to fabricate vascular junctions in the future.

Hippocampal motor memory network reorganization depends on familiarity, not time.

There is debate as to whether a time-dependent transformation of the episodic-like memory network is observed for nonepisodic tasks, including procedural motor memory. To determine how motor memory networks reorganize with time and practice, mice performed a motor task in a straight alley maze for 1 d (recent), 20 d of continuous training (continuous), or testing 20 d after the original training (remote), and then regional c-Fos expression was assessed. Elevated hippocampal c-Fos accompanied remote, but not continuous, motor task retrieval after 20 d, suggesting that the hippocampus remains engaged for nonhabitual remote motor memory retrieval.

Synergistic Induction of Solvent and Ligand-Substitution in Single-Crystal to Single-Crystal Transformations toward a MOF with Photocatalytic Dye Degradation.

External-stimuli responsiveness as found in natural organisms and smart materials is attractive for functional materials scientists who attempt to design and imitate fascinating behavior into their materials. Herein, we report a couple of new solvent-responsive isostructural two-dimensional cationic metal-organic frameworks (MOFs) of Mn(II) (1a) and Zn(II) (2a) that undergo unprecedented single-crystal to single-crystal (SCSC) transformation toward the corresponding isostructural three-dimensional MOFs of Mn(II) (1b) and Zn(II) (2b). The 2D MOFs 1a and 2a have been effortlessly and rapidly synthesized via the microwave-heating technique. The SCSC transformations are synergistically induced by solvent and ligand-substitution reactions and able to be triggered by water, methanol, ethanol, and n-propanol. Time-dependent SCSC transformations were studied by in situ X-ray diffraction. Investigations on photodegradation of methyl orange showed that Zn-MOF 2b has higher efficiency than Mn-MOF 1b under UV-C irradiation at 300 min, 94.27%, and 21.91%, respectively. The influence of charge on the dye molecules, heterogeneity of the catalysis, and •OH radical-scavenging test was studied. First-principles computations suggest that the high photocatalytic activity of 2b may be attributed to its suitable band-edge position for redox reactions.

Fully Nonlinear Evolution of Free-Surface Waves with Constant Vorticity under Horizontal Electric Fields

This work presents the results of a direct numerical simulation of the nonlinear free surface evolution of a finite-depth fluid with a linear shear flow under the action of horizontal electric fields. The method of time-dependent conformal transformation for the description of the combined effects of the electric fields and constant vorticity is generalized for the first time. The simulation results show that strong shear flow co-directed in the wave propagation direction leads to the formation of large-amplitude surface waves, and, for some limiting vorticity value, a wave breaking process with the formation of an air bubble in the liquid is possible. The oppositely directed shear flow can cause the retrograde motion of a surface wave (wave propagation in the opposite direction to the linear wave speed). The simulations conducted taking into account the electro-hydrodynamic effects demonstrate that a high enough external horizontal electric field suppresses these strongly nonlinear processes, and the surface waves tend to preserve their shape.

Efficient numerical approach for the simulations of high-power dispersive readout with time-dependent unitary transformation

Efficient numerical approach for the simulations of high-power dispersive readout with time-dependent unitary transformation

Time-dependent memory transformation in hippocampus and neocortex is semantic in nature

Memories undergo a time-dependent neural reorganization, which is assumed to be accompanied by a transformation from detailed to more gist-like memory. However, the nature of this transformation and its underlying neural mechanisms are largely unknown. Here, we report that the time-dependent transformation of memory is semantic in nature, while we find no credible evidence for a perceptual transformation. Model-based MRI analyses reveal time-dependent increases in semantically transformed representations of events in prefrontal and parietal cortices, while specific pattern representations in the anterior hippocampus decline over time. Posterior hippocampal memory reinstatement, in turn, increases over time and is linked to the semantic gist of the original memory, without a statistically significant link to perceptual details. These findings indicate that qualitative changes in memory over time, associated with distinct representational changes in the neocortex and within the hippocampus, reflect a semantic transformation, which may promote the integration of memories into abstract knowledge structures.

Fock Quantization of a Klein–Gordon Field in the Interior Geometry of a Nonrotating Black Hole

We study the canonical quantization of a scalar field in Kantowski–Sachs spacetime. For simplicity, we consider compactified spatial sections, since this does not affect the ultraviolet behavior. A time-dependent canonical transformation is performed prior to quantization. As in previously studied cases, the purpose of this canonical transformation is to identify and extract the background contribution to the field evolution which is obstructing a unitary implementation of the field dynamics at the quantum level. This splitting of the time dependence into a background piece and the part to be seen as true quantum evolution is, to a large extent, determined by the unitarity requirement itself. The quantization is performed in the usual setup of Fock representations, demanding the preservation of the spatial symmetries. Under the joint requirements of quantum unitary dynamics and compatibility with those classical symmetries, the quantization is shown to be unique, in the sense that any two representations with these properties are unitarily equivalent. This confirms the validity of our conditions as criteria to discriminate among possibly inequivalent quantum descriptions. The interest of this analysis goes beyond cosmological applications since the interior of a nonrotating black hole has a geometry of the Kantowski–Sachs type.

Phytoplankton Producer Species and Transformation of Released Compounds over Time Define Bacterial Communities following Phytoplankton Dissolved Organic Matter Pulses.

Phytoplankton-bacterium interactions are mediated, in part, by phytoplankton-released dissolved organic matter (DOMp). Two factors that shape the bacterial community accompanying phytoplankton are (i) the phytoplankton producer species, defining the initial composition of released DOMp, and (ii) the DOMp transformation over time. We added phytoplankton DOMp from the diatom Skeletonema marinoi and the cyanobacterium Prochlorococcus marinus MIT9312 to natural bacterial communities from the eastern Mediterranean and determined the bacterial responses over a time course of 72 h in terms of cell numbers, bacterial production, alkaline phosphatase activity, and changes in active bacterial community composition based on rRNA amplicon sequencing. Both DOMp types were demonstrated to serve the bacterial community as carbon and, potentially, phosphorus sources. Bacterial communities in diatom-derived DOM treatments maintained higher Shannon diversities throughout the experiment and yielded higher bacterial production and lower alkaline phosphatase activity compared to cyanobacterium-derived DOM after 24 h of incubation (but not after 48 and 72 h), indicating greater bacterial usability of diatom-derived DOM. Bacterial communities significantly differed between DOMp types as well as between different incubation times, pointing to a certain bacterial specificity for the DOMp producer as well as a successive utilization of phytoplankton DOM by different bacterial taxa over time. The highest differences in bacterial community composition with DOMp types occurred shortly after DOMp additions, suggesting a high specificity toward highly bioavailable DOMp compounds. We conclude that phytoplankton-associated bacterial communities are strongly shaped by the phytoplankton producer as well as the transformation of its released DOMp over time. IMPORTANCE Phytoplankton-bacterium interactions influence biogeochemical cycles of global importance. Phytoplankton photosynthetically fix carbon dioxide and subsequently release the synthesized compounds as dissolved organic matter (DOMp), which becomes processed and recycled by heterotrophic bacteria. Yet the importance of phytoplankton producers in combination with the time-dependent transformation of DOMp compounds on the accompanying bacterial community has not been explored in detail. The diatom Skeletonema marinoi and the cyanobacterium Prochlorococcus marinus MIT9312 belong to globally important phytoplankton genera, and our study revealed that DOMp of both species was selectively incorporated by the bacterial community. The producer species had the highest impact shortly after DOMp appropriation, and its effect diminished over time. Our results improve the understanding of the dynamics of organic matter produced by phytoplankton in the oceans as it is utilized and modified by cooccurring bacteria.

Biological scaffold implants in a murine volumetric muscle loss trauma model cause time dependent CD62L and CD101 upregulation on “regulatory like” eosinophils.

Abstract Introduction: Previously, we reported a strong increase in the recruitment of eosinophils at injured muscle when treated with a biologic scaffold implant. As such, we sought to characterize the surface marker expression of these eosinophils to understand their role at the site of injury. Method: Volumetric muscle loss (VML) model was performed on C57BL/6 mice and was subsequently treated with a biologic scaffold (decellularized extracellular matrix). After 7 and 21 days, post-injury, implanted material along with injured tissue was dissected and converted to single cell suspension for flow cytometry. Results: Compared to uninjured mice, at both 7 and 21 days time point, mice that received biological scaffold featured significantly increased presence of eosinophils at the site of injury. These eosinophils had a ring-shaped nucleus which has been previously associated with regulatory eosinophils. Eosinophils at the site of injury showed time dependent upregulation of CD101 (Mean fold change from uninjured muscle after 7 days post implant was 2.73 and the same was 9.90 after 21 days, (p<0.0001)), and CD62L (Mean fold change from uninjured muscle after 7 days post implant was 3.65 and the same was 11.64 after 21 days(p<0.0001)) expression. Interestingly, the same pattern was not observed with blood eosinophils except that the blood eosinophils at 3-week timepoint were featuring a significant increase in CD62L expression compared with 1 week time point, suggesting potential return of homeostasis in circulatory compartment. Conclusion: Here, we describe time-dependent transformation in eosinophil phenotype in response to biologic scaffold implantation, including upregulation of adhesion molecule CD62L and a regulatory marker CD101.

Time-dependent emotional memory transformation: Divergent pathways of item memory and contextual dependency.

Emotional memory can persist strikingly long, but it is believed that not all its elements are protected against the fading effects of time. So far, studies of emotional episodic memory have mostly investigated retention up to 24h postencoding and revealed that central emotional features (items) are usually strengthened, while contextual binding of the event is reduced. However, even though it is known for neutral memories that central versus contextual elements evolve differently with longer passage of time, the time-dependent evolution of emotional memories remains unclear. Hypothetically, compared to neutral memories, emotional item memory becomes increasingly stronger, accompanied by accelerated decay of-already fragile-links with their original encoding contexts, resulting in progressive reductions in contextual dependency. Here, we tested these predictions in a large-scale study. Participants encoded emotional and neutral episodes, and were assessed 30 minutes (N = 40), 1 day (N = 40), 1 week (N = 39), or 2 weeks (N = 39) later on item memory, contextual dependency, and subjective quality of memory. The results show that, with the passage of time, emotional memories were indeed characterized by increasingly stronger item memory and weaker contextual dependency. Interestingly, analyses of the subjective quality of memories revealed that stronger memory for emotional items with time was expressed in familiarity, whereas increasingly smaller contextual dependency for emotional episodes was reflected in recollection. Together, these findings uncover the time-dependent transformation of emotional episodic memories, thereby shedding light on the ways healthy and maladaptive human memories may develop. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

On Sultana–Dyer spacetime: Curvatures and geometric structures

Sultana–Dyer black hole, obtained by a time-dependent conformal transformation of Schwarzschild black hole, is an exact solution of general relativity in spherical symmetry. This paper provides the investigation of geometrical properties of the Sultana–Dyer spacetime by means of covariant derivative(s) of the geometric quantity “curvature”. It is shown that such a spacetime is [Formula: see text]-quasi-Einstein, Einstein spacetime of level [Formula: see text] and fulfills the generalized Roter type condition. The spacetime admits pseudosymmetric Weyl curvature as well as pseudosymmetric conharmonic curvature. Also, Weyl compatibility and Riemann compatibility of the Ricci tensor are shown. Finally, a comparison is drawn between Schwarzschild and Sultana–Dyer spacetimes with respect to their curvature restricted geometric properties.

Condensate's ageing modelled through molecular dynamics: Protein structural transitions critically transform the network connectivity and viscoelasticity of RNA-binding protein condensates.

Biomolecular condensates, some of which are liquid-like during health, can age over time becoming gel-like pathological systems. Ageing of RNA-binding protein condensates can emerge from the progressive accumulation of inter-protein β-sheets. To bridge microscopic understanding of such time-dependent transformation with the modulation of FUS and hnRNPA1 condensate viscoelasticity, we develop a multiscale simulation approach. Our method integrates atomistic simulations with sequence-dependent coarse-grained modelling of condensates that age over time due to accumulation of inter-protein β-sheets. We reveal that ageing notably increases condensate viscosity but does not transform the phase diagrams. Strikingly, the network of molecular connections within condensates is drastically altered during ageing and culminates in gelation when the network of strong inter-protein β-sheets fully percolates. High concentrations of RNA decelerate the accumulation of inter-protein β-sheets, abrogating the effects of ageing.

An Introduction to PT-Symmetric Quantum Mechanics-Time-Dependent Systems

I will provide a pedagogical introduction to non-Hermitian quantum systems that are PT-symmetric, that is they are left invariant under a simultaneous parity transformation (P) and time-reversal (T). I will explain how generalised versions of this antilinear symmetry can be utilised to explain that these type of systems possess real eigenvalue spectra in parts of their parameter spaces and how to set up a consistent quantum mechanical framework for them that enables a unitary time-evolution. In the second part I will explain how to extend this framework to explicitly time-dependent Hamiltonian systems and report in particular on recent progress made in this context. I will explain how to construct the essential key quantity in this framework, the time-dependent Dyson map and metric and solutions to the time-dependent Schrödinger equation, in an algebraic fashion, using time-dependent Darboux transformations, utilising Lewis-Riesenfeld invariants, point transformations and some approximation methods. I comment on the ambiguities of this metric and demonstrate that this can even lead to infinite series of metric operators. I conclude with some applications to PT-symmetrically coupled oscillators, demonstrate the equivalence of the time-dependent double wells and unstable anharmonic oscillators and show how the unphysical PT-symmetrically broken regions in the parameter space for the time-independent theory becomes physical in the explicitly time-dependent systems. I discuss how this leads to a prolongation of the otherwise rapidly decaying von Neumann entropy. The so-called sudden death of the entropy is stopped at a finite value.1

Four-Dimensional Printing of Stimuli-Responsive Hydrogel-Based Soft Robots.

The present protocol describes the creation of four-dimensional (4D), time-dependent, shape-changeable, stimuli-responsive soft robots using a three-dimensional (3D) bio-printing method. Recently, 4D printing techniques have been extensively proposed as innovative new methods for developing shape-transformable soft robots. In particular, 4D time-dependent shape transformation is an essential factor in soft robotics because it allows effective functions to occur at the right time and place when triggered by external cues, such as heat, pH, and light. In line with this perspective, stimuli-responsive materials, including hydrogels, polymers, and hybrids, can be printed to realize smart shape-transformable soft robotic systems. The current protocol can be used to fabricate thermally responsive soft grippers composed of N-isopropylacrylamide (NIPAM)-based hydrogels, with overall sizes ranging from millimeters to centimeters in length. It is expected that this study will provide new directions for realizing intelligent soft robotic systems for various applications in smart manipulators (e.g., grippers, actuators, and pick-and-place machines), healthcare systems (e.g., drug capsules, biopsy tools, and microsurgeries), and electronics (e.g., wearable sensors and fluidics).

Time-dependent transformations of the internal image of disorder in patients with chronic back pain

Rationale: Pain is the most prevalent symptom of any disease, with back pain comprising 12 to 33%. Chronic back pain ranges fourth among the causes of disability. About 60% of patients with chronic pain have symptoms of depression. However, there is paucity of empirical data on psychological aspects of the pain syndrome chronization in patients with back pain.
 Aim: To study the temporary transformation of the internal image of disorder in patients with chronic back pain.
 Materials and methods: In this observational cohort analytical study, we evaluated the contribution of pain duration into the formation of the internal image of disorder in 84 patients with chronic pain lasting for up to 55 years and caused by dorsopathy. The patients (53 women and 31 men aged 23 to 86 years, with pain intensity of up to moderate degree) were those admitted to an in-patient department for the secondary medical rehabilitation. The internal image of disorder was operationalized with the following psychometric scales: McGill Pain Questionnaire, the Restoration of the Locus of Control Scale, the Tampa Scale of Kinesiophobia, and the Psychological Factors of Attitudes to the Disease and its Treatment Scale.
 Results: The sensory level of the internal image of disorder was characterized by mixed (neuropathic and dysfunctional) pain in 29 (34.5%) of the cases and nociceptive pain in 55 (65.5%) of the cases. In the patients with nociceptive pain, the duration of pain was negatively correlated with their perception of self-efficacy towards the disease (the intellectual level of the internal image of disorder). With time, their self-confidence and the ability to get rid of pain was decreasing (R = -0.32, p = 0.02). The decrease looked like waning fluctuations with a maximum decline rate in the second year of the disease.
 Conclusion: During the first year from the disease manifestation, patients with nociceptive pain are convinced that they have all necessary resources to cope with the disease; mandatory psychological support should be provided to them in the second year, with a dramatic drop of their self-efficacy. As for patients with mixed types of pain, the inclusion of sessions with a medical psychologist into their individual rehabilitation plan is advisable regardless of the duration of the pain syndrome.