In recent decades, there has been a great deal of interest in conducting polymers due to their broad applications. At the same time, various synthetic techniques have been developed to produce ...various nanostructures of the conducting polymers with their fascinating properties. However, the techniques for the manufacture of 2D nanosheets are either complex or expensive. No comprehensive approach for constructing 2D and 3D materials or their composites has been documented. Herein, a simple and scalable synthetic protocol is reported for the design of 2D, 3D, and related conducting polymer nanocomposites by interface manipulation in a bicontinuous microemulsion system. In this method, diverse bicontinuous thin layers of oil and water are employed to produce 2D nanosheets of conducting polymers. For the fabrication of 3D polypyrrole (PPY) and their composites, specially designed linkers of the monomers are applied to lock the 3D networks of the conducting polymers and their composites. The technique can be extended to the fabrication of most conducting polymer composites, being cost‐effective and easily scalable. The optimum electrical conductivity obtained for 2D PPY nanosheets is 219 S cm−1, the highest literature value reported to date to the best of knowledge.
A strategic synthesis technique based on a bicontinuous microemulsion system is developed to design nanostructures of conducting polymers including 2D, 3D, and nanocomposites with tailored electrical properties and morphologies.
Cell and tissue morphogenesis depends on the correct regulation of non-muscle Myosin II, but how this motor protein is spatiotemporally controlled is incompletely understood. Here, we show that in ...asymmetrically dividing Drosophila neural stem cells, cell intrinsic polarity cues provide spatial and temporal information to regulate biased Myosin activity. Using live cell imaging and a genetically encoded Myosin activity sensor, we found that Drosophila Rho kinase (Rok) enriches for activated Myosin on the neuroblast cortex prior to nuclear envelope breakdown (NEB). After NEB, the conserved polarity protein Partner of Inscuteable (Pins) sequentially enriches Rok and Protein Kinase N (Pkn) on the apical neuroblast cortex. Our data suggest that apical Rok first increases phospho-Myosin, followed by Pkn-mediated Myosin downregulation, possibly through Rok inhibition. We propose that polarity-induced spatiotemporal control of Rok and Pkn is important for unequal cortical expansion, ensuring correct cleavage furrow positioning and the establishment of physical asymmetry.
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•The polarity protein Pins is necessary for biased Myosin activity•Pins controls Rok's asymmetric enrichment and apical localization of Pkn•Both Rok and Pkn spatiotemporally regulate Myosin's dynamic relocalization•Spatiotemporal control of Myosin activity is necessary for physical asymmetry
Most cells divide symmetrically, but several cell types are known to generate unequal-sized siblings with different functions. Tsankova et al. report that the conserved polarity protein Pins controls the activity of the motor protein Myosin through two protein kinases, to ensure that Drosophila neural stem cells divide asymmetrically.
Asymmetric cell division, creating sibling cells with distinct developmental potentials, can be manifested in sibling cell size asymmetry. This form of physical asymmetry occurs in several metazoan ...cells, but the underlying mechanisms and function are incompletely understood. Here we use Drosophila neural stem cells to elucidate the mechanisms involved in physical asymmetry establishment. We show that Myosin relocalizes to the cleavage furrow via two distinct cortical Myosin flows: at anaphase onset, a polarity induced, basally directed Myosin flow clears Myosin from the apical cortex. Subsequently, mitotic spindle cues establish a Myosin gradient at the lateral neuroblast cortex, necessary to trigger an apically directed flow, removing Actomyosin from the basal cortex. On the basis of the data presented here, we propose that spatiotemporally controlled Myosin flows in conjunction with spindle positioning and spindle asymmetry are key determinants for correct cleavage furrow placement and cortical expansion, thereby establishing physical asymmetry.
Carcinoembryonic antigen (CEA) is a critical biomarker for identifying colon cancer. This work presents an electrochemical impedance spectroscopy (EIS) based aptasensor for detecting CEA, utilizing a ...single-stranded DNA (ssDNA) aptamer previously selected and characterized by our research group. The surface of an interdigitated gold electrode (IDE) was successfully functionalized with an 18-HEG-modified aptamer sequence. The developed aptasensor demonstrated high specificity and sensitivity with detection limits of 2.4 pg/mL and 3.8 pg/mL for CEA in buffer and human serum samples, respectively. The optimal incubation time for the target protein was 20 min, and EIS measurements took less than 3 min. Atomic force microscopy (AFM) micrographs supported the EIS data, demonstrating a change in IDE surface roughness after each modification step, confirming the successful capture of the target. The potential of this developed EIS aptasensor in detecting CEA in complex samples holds promise.
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•A label-free EIS aptasensor for rapid and sensitive detection of CEA was developed•Detection limits of 2.4 pg/mL in buffer and 3.8 pg/mL in human serum were attained•Incubation time was 20 min, while the EIS measurements took less than 3 min•AFM validated successful target protein capture
Bio-electrochemistry; Applied sciences; Sensor system
Centrosomes, the main microtubule organizing centers (MTOCs) of metazoan cells, contain an older "mother" and a younger "daughter" centriole. Stem cells either inherit the mother or ...daughter-centriole-containing centrosome, providing a possible mechanism for biased delivery of cell fate determinants. However, the mechanisms regulating centrosome asymmetry and biased centrosome segregation are unclear. Using 3D-structured illumination microscopy (3D-SIM) and live-cell imaging, we show in fly neural stem cells (neuroblasts) that the mitotic kinase Polo and its centriolar protein substrate Centrobin (Cnb) accumulate on the daughter centriole during mitosis, thereby generating molecularly distinct mother and daughter centrioles before interphase. Cnb's asymmetric localization, potentially involving a direct relocalization mechanism, is regulated by Polo-mediated phosphorylation, whereas Polo's daughter centriole enrichment requires both Wdr62 and Cnb. Based on optogenetic protein mislocalization experiments, we propose that the establishment of centriole asymmetry in mitosis primes biased interphase MTOC activity, necessary for correct spindle orientation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Recent developments of orthopedic implant applications have discovered a variety of new metallic biomaterials known as β-type titanium alloys. The μ-WEDM (micro-wire electro discharge machining) ...surface treatment technique, capable of improving the surface properties of orthopedic implants, was studied in a machining Ti-29Nb-13Ta-4.6Zr alloy. This study aimed to evaluate material removal rate (MRR), kerf width, average surface roughness, microhardness and antibacterial response at different machining parameters which are capacitance (1 nF, 10 nF and 100 nF) and gap voltage (80 V, 95 V and 110 V). The Taguchi method was used to optimize the mentioned output parameters, while ANOVA (analysis of variance) described the significance and contribution of capacitance and gap voltage. Grey relation analysis (GRA) was conducted to perform multiple output optimization. For antibacterial response, cultivations of B. subtilis, E. coli, P. aeruginosa and S. aureus bacteria on treated surfaces for 72 h were performed. As the results, optimal values of MRR, kerf width, crater area, average surface roughness and microhardness were equal to 0.0637 mm3/min, 93.0 μm, 21.8 μm2, 0.348 μm and 442 HV, respectively. Meanwhile, μ-WEDM treatment improved antibacterial properties while the highest antibacterial response was achieved at the lowest average surface roughness resulting in least biofilm formation on treated surfaces.
We investigate the dynamics of the collapse of a single copolymer chain, when the solvent quality is suddenly quenched from good to poor. We employ Brownian dynamics simulations of a bead−spring ...chain model and incorporate fluctuating hydrodynamic interactions via the Rotne−Prager−Yamakawa tensor. Various copolymer architectures are studied within the framework of a two-letter HP model, where monomers of type H (hydrophobic) attract each other, while all interactions involving P (polar or hydrophilic) monomers are purely repulsive. The hydrodynamic interactions are found to assist the collapse. Furthermore, the chain sequence has a strong influence on the kinetics and on the compactness and energy of the final state. The dynamics is typically characterized by initial rapid cluster formation, followed by coalescence and final rearrangement to form the compact globule. The coalescence stage takes most of the collapse time, and its duration is particularly sensitive to the details of the architecture. Long blocks of type P are identified as the main bottlenecks to find the globular state rapidly.
Human tumors exhibit plasticity and evolving capacity over time. It is difficult to study the mechanisms of how tumors change over time in human patients, in particular during the early stages when a ...few oncogenic cells are barely detectable. Here, we used a
tumor model caused by loss of
(
), a highly conserved apicobasal cell polarity gene, to investigate the spatial-temporal dynamics of early tumorigenesis events. The fly
mutant tumors have been successfully used to model many aspects of tumorigenesis processes. However, it is still unknown whether
mutant tumors exhibit plasticity and evolvability along the temporal axis. We found that
mutant tumors displayed different growth rates and cell cycle profiles over time, indicative of a growth arrest-to-proliferation transition as the
mutant tumors progress. Longitudinal bulk and single-cell transcriptomic analysis of
mutant tumors revealed that the MAPK pathway, including JNK and ERK signaling activities, showed quantitative changes over time. We found that high JNK signaling activity caused G2/M cell cycle arrest in early
mutant tumors. In addition, JNK signaling activity displayed a radial polarity with the JNK
cells located at the periphery of
mutant tumors, providing an inherent mechanism that leads to an overall decrease in JNK signaling activity over time. We also found that ERK signaling activity, in contrast to JNK activity, increased over time and promoted growth in late-stage
mutant tumors. Furthermore, high JNK signaling activity repressed ERK signaling activity in early
mutant tumors. Together, these data demonstrate that dynamic MAPK signaling activity, fueled by intratumor heterogeneity derived from tissue topological differences, drives a growth arrest-to-proliferation transition in
mutant tumors.This article has an associated First Person interview with the joint first authors of the paper.
Abstract This study investigates the temperature‐dependent micellization behaviors of saponin and sodium dodecyl sulfate (SDS) surfactants, which are both important for chemical enhanced oil recovery ...(CEOR). It also evaluates the effect of silica nanoparticles (SiO2) on these behaviors, given the growing interest in nanoparticle‐enhanced surfactants. The research focuses on the tunable properties of nanoparticle‐surfactant combinations. The structural differences between saponin and SDS were identified using FT‐IR and H‐NMR. The Du Noüy ring method was used to measure surface tension at various concentrations and temperatures (25–75 °C). FTIR analysis showed distinct differences between SDS and Saponin, associated with head group where there is hydroxyl groups in SDS solution. H‐NMR showed higher complexity of Saponin's structure, evidenced by its diverse sugar‐related proton peaks. Both SDS and Saponin reduce surface tension with temperature; SDS is more effective, lowering it to 42.1 mN/m versus 48.5 mN/m for Saponin. With SiO2, tensions drop to 39.2 mN/m for SDS and 45.5 mN/m for Saponin. Both surfactants maintain CMCs under reservoir temperature in the 0.05–0.1 wt % range. Saponin exhibited a more negative ΔG° and consistently negative ΔH°, indicating a thermodynamically favorable exothermic reaction. The novelty of this study lies in its focus on both anionic and nonionic surfactants under simulated reservoir conditions. The study focuses on the role of nanoparticles in enhancing surfactant stability and efficiency by addressing thermodynamic parameters.
Herein, we reported a facile method to fabricate the exfoliated graphite (EG) by Hummer’s method via a two-step procedure including intercalation with a mixture of oxidants (H2O2 and H2SO4), and ...exfoliation using a microwave system. For the adsorption experiments, effect of contact time (0–210 min), initial concentration (20–60 mg/L), pH (4–10), and EG dosage (0.3–0.7 g/L) were systematically studied. Moreover, the adsorption kinetics (pseudo-first-order, pseudo-second-order, Elovich, and Bangham) and isotherms (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were carried out to elucidate the mechanism of CR adsorption over EG. Due to high porosity (40.95 m2/g) and large maximum adsorption capacity of CR (80.775 mg/g), the EG derived from natural graphite can be an effective adsorbent for CR dye treatment in aqueous solution.
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