The minimal chemotactic cell.

The movement of cells and microorganisms in response to chemical gradients, chemotaxis, is fundamental to the evolution of myriad biological processes. In this work, we demonstrate that even the simplest cell-like structures are capable of chemotactic navigation. By encapsulating enzymes within lipid vesicles that incorporate a minimal number of membrane pores, we reveal that a solitary vesicle can actively propel itself toward an enzyme substrate gradient.

Study of defect-induced magnetic anisotropy in MWCNT and RGO dispersed SnTe using spin resonance and magnetic measurement.

Magnetism in topological materials has drawn significant attention due to its crucial role in stabilizing exotic quantum states. In topological crystalline insulators (TCIs), such as SnTe, the topological protection of energy bands arises from mirror symmetries in the crystal structure. When these symmetries are broken, new quantum phases, such as the quantum anomalous Hall and axion insulator states, can emerge.

Technology Roadmap of Micro/Nanorobots.

Inspired by Richard Feynman's 1959 lecture and the 1966 film , the field of micro/nanorobots has evolved from science fiction to reality, with significant advancements in biomedical and environmental applications. Despite the rapid progress, the deployment of functional micro/nanorobots remains limited. This review of the technology roadmap identifies key challenges hindering their widespread use, focusing on propulsion mechanisms, fundamental theoretical aspects, collective behavior, material design, and embodied intelligence.

Dual Capture of Iodine and Methyl Iodide Using Nonporous Nitrogen-Enriched Palladium(II) Assemblies.

The increasing reliance on nuclear energy amid fossil fuel depletion has intensified the demand for effective materials to capture and store radioactive species. Among these, molecular iodine and methyl iodide present serious environmental and health risks due to their volatility and persistence in nuclear waste. Herein, four nonporous self-assembled metallo-supramolecular assemblies (-) containing nitrogen-enriched cores (pyridyl, pyrimidine, or phenazine units) with distinct cavity sizes were investigated for their potential in simultaneous capture of both iodine and organic iodide.

Study of proximity-coupled magnetic anisotropy in V-doped SnTe using spin resonance and magnetic measurements.

SnTe is a topological crystalline insulator with topological surface states (TSSs) protected by crystal symmetries. This, along with an associated Berry-phase π, results in a positive quantum correction in electrical conductivity, known as weak antilocalization (WAL). The applied magnetic field breaks down the TSS protection, resulting in a cusp-like negative magnetoconductance (MC).

Hot carrier harvesting at the interface of CsPbI nanocrystals.

We investigate the solution-phase harvesting of hot carriers (HCs) at the interface of CsPbI nanocrystals (NCs) and -methyl aniline (NMA). NMA, chosen for its specific band alignments, enables the extraction of above band-edge carriers thermodynamically favorable while effectively suppressing carrier transfer at the band-edge. Stern-Volmer (SV) analysis based on TCSPC-recorded lifetimes shows the carrier transfer rate approaches the diffusion-controlled limit in toluene.

Enzyme Controlled Transient Phospholipid Vesicles for Regulated Cargo Release.

Metabolism in biological systems involves the continuous formation and breakdown of chemical and structural components, driven by chemical energy. In specific, metabolic processes on cellular membranes result in in situ formation and degradation of the constituent phospholipid molecules, by consuming fuel, to dynamically regulate the properties. Synthetic analogs of such chemically fueled phospholipid vesicles have been challenging.

Database of soil properties incorporating organic content from roots and soil organisms for regional slope stabilisation.

The effectiveness of using vegetation to reinforce slopes is influenced by the soil and vegetation characteristics. Hence, this study pioneers the construction of an extensive soil database using random forest machine learning and ordinary kriging methods, focusing on the influence of plant roots on the saturated and unsaturated properties of residual soils. Soil organic content, which includes contributions from both soil organisms and roots, functions as a key factor in estimating soil hydraulic and mechanical properties influenced by vegetation roots.

Non-convergence of the blinking timescale of twelve-faceted perovskite nanocrystals observed through an advanced fluorescence correlation spectroscopy study.

Single-particle photoluminescence measurements have been extensively utilized to investigate the charge carrier dynamics in quantum dots (QDs). Among these techniques, single dot blinking studies are effective for probing relatively slower processes with timescales >10 ms, whereas fluorescence correlation spectroscopy (FCS) studies are suited for recording faster processes with timescales typically <1 ms. In this study, we utilized scanning FCS (sFCS) to bridge the ms gap, thereby enabling the tracking of carrier dynamics across an extended temporal window ranging from μs to subsecond.

N-Heteroatom Engineered Nonporous Amorphous Self-Assembled Coordination Cages for Capture and Storage of Iodine.

Radioactive iodine isotopes from nuclear-related activities, present substantial risks to human health and the environment. Developing effective materials for the capture and storage of these hazardous molecules is paramount. Traditionally, nonporous solids were historically considered ineffective for adsorbing target species.

Unveiling the Influence of Brightness Heterogeneity in Fluorescence Correlation Spectroscopy of Perovskite Nanocrystals.

Nanoparticles (NPs), including perovskite nanocrystals (PNCs) with single photon purity, present challenges in fluorescence correlation spectroscopy (FCS) studies due to their distinct photoluminescence (PL) behaviors. In particular, the zero-time correlation amplitude [g(0)] and the associated diffusion timescale (τ) of their FCS curves show substantial dependency on pump intensity (I). Optical saturation inadequately explains the origin of this FCS phenomenon in NPs, thus setting them apart from conventional dye molecules, which do not manifest such behavior.

Photoresponse of Carbon Nanofiber-Based Photodetector and Its Enhancement on CuNi Nanoparticle Adsorption.

We explore the photodetection properties of a carbon nanofiber (CNF)-based p-CNF/n-Si heterojunction device in the 400-800 nm wavelength range and investigate the changes brought in by adsorption of CuNi (CN) nanoparticles on the CNFs. The nanoparticles and CN-CNF nanocomposites were synthesized by using chemical hydrothermal routes. The p-type semiconducting nature of the CNFs and nanocomposites was determined using X-ray photoelectron (XPS) and UV-vis spectroscopies.

Facet Dependent Photoluminescence Blinking from Perovskite Nanocrystals.

Photoluminescence (PL) blinking of nanoparticles, while detrimental to their imaging applications, may benefit next-generation displays if the blinking is precisely controlled by reversible electron/hole injections from an external source. Considerable efforts are made to create well-characterized charged excitons within nanoparticles through electrochemical charging, which has led to enhanced control over PL-blinking in numerous instances. Manipulating the photocharging/discharging rates in nanoparticles by surface engineering can represent a straightforward method for regulating their blinking behaviors, an area largely unexplored for perovskite nanocrystals (PNCs).

Assessment of chitosan-coated zinc cobalt ferrite nanoparticle as a multifunctional theranostic platform facilitating pH-sensitive drug delivery and OCT image contrast enhancement.

Colorectal cancer (CC) is one of the most predominant malignancies in the world, with the current treatment regimen consisting of surgery, radiation therapy, and chemotherapy. Chemotherapeutic drugs, such as 5-fluorouracil (5-FU), have gained popularity as first-line antineoplastic agents against CC but have several drawbacks, including variable absorption through the gastrointestinal tract, inconsistent liver metabolism, short half-life, toxicological reactions in several organ systems, and others. Therefore, herein, we develop chitosan-coated zinc-substituted cobalt ferrite nanoparticles (CZCFNPs) for the pH-sensitive (triggered by chitosan degradation within acidic organelles of cells) and sustained delivery of 5-FU in CC cells in vitro.

Photosynthetic gas exchange, plant water relations and osmotic adjustment of three tropical perennials during drought stress and re-watering.

Planting vegetation on slopes is an effective way of improving slope stability while enhancing the aesthetic appearance of the landscape. However, plants growing on slopes are susceptible to natural drought stress (DS) conditions which commonly lead to water deficit in plant tissues that affect plant health and growth. This study investigated the photosynthetic gas exchange, plant water status and proline accumulation of three tropical perennials namely Clerodendrum paniculatum, Ipomoea pes-caprae and Melastoma malabathricum after being subjected to DS and re-watering (RW).

Optical Anisotropy and Dimple Formation on Films Formed after Drying of Gelatinized Starch Solution Droplets.

We study the microstructures in the drying droplets of gelatinized starch solutions on a flat substrate. Cryogenic scanning electron microscopy studies on the vertical cross-section of these drying droplets for the first time reveal a relatively thinner solid elastic crust of uniform thickness at the free surface, an intermediate mesh region below the crust, and an inner core of a cellular network structure made of starch nanoparticles. We find that the deposited circular films formed after drying are birefringent and azimuthally symmetric with a dimple at their center.

Dodecahedron CsPbBr Perovskite Nanocrystals Enable Facile Harvesting of Hot Electrons and Holes.

This Letter reports the facile harvesting of hot carriers (HCs) in a composite of 12-faceted dodecahedron CsPbBr nanocrystal (NC) and a scavenger molecule. We recorded ∼3.3 × 10 s HC cooling rate in NC when excited with ∼1.

Unveiling the theoretical aspects of superelectrophilic activation in an inverse demand Diels-Alder reaction.

The present computational study using B3LYP functional and 6-31+G(d) basis set has been accomplished to investigate the mechanism of the inverse demand Diels-Alder reaction between pyridyl imine and propene. The highly charged dicationic superelectrophilic diene with exceptionally low-lying LUMO makes the cycloaddition reaction with propene more favorable by significantly lowering the activation energy. The Wiberg bond indices are calculated in accordance with the formation and breaking processes of bonds.

Facet Engineering for Decelerated Carrier Cooling in Polyhedral Perovskite Nanocrystals.

We report here the hot carrier (HC) cooling time scales within polyhedral CsPbBr nanocrystals (NCs) characterized by different numbers of facets (6 to 26) utilizing a femtosecond upconversion setup. Interestingly, the observed cooling time scale slows many-fold (>10 times) upon opening the new facets on the NC surface. Furthermore, a temperature-dependent study reveals that cooling in multifaceted NCs is polaron mediated, where newly opened polar facets and the soft lattice of CsPbBr NCs play pivotal roles.

Kinetochore- and chromosome-driven transition of microtubules into bundles promotes spindle assembly.

Mitotic spindle assembly is crucial for chromosome segregation and relies on bundles of microtubules that extend from the poles and overlap in the middle. However, how these structures form remains poorly understood. Here we show that overlap bundles arise through a network-to-bundles transition driven by kinetochores and chromosomes.

Deconstructing the role of myosin contractility in force fluctuations within focal adhesions.

Force fluctuations exhibited in focal adhesions that connect a cell to its extracellular environment point to the complex role of the underlying machinery that controls cell migration. To elucidate the explicit role of myosin motors in the temporal traction force oscillations, we vary the contractility of these motors in a dynamical model based on the molecular clutch hypothesis. As the contractility is lowered, effected both by changing the motor velocity and the rate of attachment/detachment, we show analytically in an experimentally relevant parameter space, that the system goes from decaying oscillations to stable limit cycle oscillations through a supercritical Hopf bifurcation.

Subpicosecond Hot Hole Transfer in a Graphene Quantum Dot Composite with High Efficiency.

Extraction of hot carriers is of prime importance because of its potential to overcome the energy loss that limits the efficiency of an optoelectronic device. Employing a femtosecond upconversion setup, herein we report a few picoseconds carrier cooling time of colloidal graphene quantum dots (GQDs) is at least an order of magnitude slower compared to that in its bulk form. A slower carrier cooling time of GQDs compared to that of the other semiconductor quantum dots and their bulk materials is indeed a coveted property of GQDs that would allow one easy harvesting of high energy species employing a suitable molecular system as shown in this study.

Assessment of heavy metal and metalloid levels and screening potential of tropical plant species for phytoremediation in Singapore.

Heavy metal or metalloid contamination is a common problem in soils of urban environments. Their introduction can be due to unpremeditated anthropogenic activities like atmospheric deposition produced by diffuse sources, construction activities and landscape maintenance. Phytoremediation is a rapidly evolving, sustainable approach to remediate the contaminated lands where metals and metalloids are highly persistent in the environment.

Pattern formation, localized and running pulsation on active spherical membranes.

Active force generation by an actin-myosin cortex coupled to a cell membrane allows the cell to deform, respond to the environment, and mediate cell motility and division. Several membrane-bound activator proteins move along it and couple to the membrane curvature. Besides, they can act as nucleating sites for the growth of filamentous actin.