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Regarding the 2- d i s t a n c e coloring of planar graphs, in 1977, Wegner conjectured that for a graph G : (1) χ 2 (G) ≤ 7 if Δ (G) = 3. (2) χ 2 (G) ≤ Δ (G) + 5 if 4 ≤ Δ (G) ≤ 7. (3) χ 2 (G) ≤ ⌊ 3 2 Δ (G) ⌋ + 1 if Δ (G) ≥ 8. In this paper, we proved that for every planar graph with maximum degree Δ (G) ≤ 4 : (1) χ 2 l (G) ≤ 1 0 if g (G) ≥ 6. (2) χ 2 l (G) ≤ 7 if g (G) ≥ 1 0. [ABSTRACT FROM AUTHOR]

A non-Robertsonian wheat-rye chromosome translocation was observed in pollen-derived line WER-1-1 from the F1 hybrid between M27 [a 1R(1D) substitution line] and `Chinese Spring'. Biochemical assays of high molecular weight glutenin subunits and gliadin components and Southern hybridization of dispersed rye repeat sequences pSc 119.2 and pSc 5.3H3 provided sufficient evidence that in WER-1-1, wheat chromosome pair 1D was substituted by 1R chromosome pair. C-banding and genomic in situ hybridization further revealed that the 1R chromosomes, present in WER-1-1, were abnormal in that the distal parts of their long arms were lost and translocated to the long arm ends of a pair of wheat chromosomes. The mode of origin of this translocation is also discussed., Several principles and methodologies of inducing chromosome translocations have been reviewed by Sears (1981), Feldman (1988), and Jiang et al. (1994). These techniques can be classified into two major groups. [...]

Cysteine‐functionalized Fe3O4 magnetic nanoparticles were synthesized by thiol‐ene click reaction and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction spectrometry (XRD), thermal gravimetric analysis (TGA), vibrating sample magnetometer (VSM), X‐ray photoelectron spectroscopy (XPS), specific surface area (BET) analysis and pore size distribution analysis. The obtained magnetic materials were employed as a magnetic solid phase extraction adsorbent combined with inductively coupled plasma‐atomic emission spectrometry (ICP‐AES) for determination of Cu2+. Several parameters affecting extraction efficiency, including eluent concentration, adsorption time, adsorbent amounts, and sample pH were investigated. Under the optimized conditions, the method was validated. Within the concentration range of 0.01–20 μg mL−1, The limit of detection (LOD) and the limit of quantification (LOQ) were determined to be 0.002 μg mL−1 and 0.007 μg mL−1, respectively. The adsorption percentage of Cu2+ ions remained above 87.0 % when the adsorption‐desorption data of Cu2+ ions through three cycles of the successive adsorption and desorption process. The results show that a reliable and rapid method was established for determination of Cu2+ ions. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a debilitating neurodegenerative disorder characterized by dopaminergic neuron degeneration. Neural stem cell (NSC) therapy offers promise for replacing these neurons and restoring neural function. However, directing NSCs to become dopaminergic neurons is challenging. Retinoic acid (RA) is a potential regulator, but its insolubility in water limits its use in PD therapy. Herein, nanonizing RA with calcium acetate to create calcium‐retinoic acid nanoparticles (Ca‐RA NPs) is proposed. These nanoparticles can be internalized by NSCs and then dissociated in the acidic environment of lysosomes to lead to a burst of Ca2+ and RA. In vitro results showed that the intracellular bursting of Ca2+ and RA accelerated neuronal differentiation and maturation by 5–10 days compared to spontaneous NSC differentiation. Importantly, Ca‐RA NPs uniquely directed NSCs to dopaminergic neurons, involving the interaction between the calcium ion‐mediated MAPK signaling pathway and the RA‐mediated RA signaling pathway. Animal experiments further validated the efficacy of Ca‐RA‐coated NSCs in restoring motor and cognitive functions in PD mice by rapidly forming dopaminergic neural circuits. Given that both RA and calcium acetate are approved by the FDA, this strategy has the potential for translation into a clinical treatment approach for stem cell therapy of PD. [ABSTRACT FROM AUTHOR]

Luminol chemiluminescence (CL) sensing system remains an excellent candidate for application in bioanalysis due to its good water solubility. However, traditional luminol CL system usually requires the addition of oxidizing agents and sensitizers to obtain high efficiency for the improvement of detection sensitivity. Although numerous studies on the nanomaterial-enhanced luminol CL systems have been carried out, there is still great potential to develop inexpensive, readily available and easily handled catalysts to construct simple and effective CL platform for biomolecular sensing. Few-layered MoS 2 nanosheets (NS) prepared by sonication-assisted exfoliation of commercially available bulk MoS 2 were found to significantly enhance the CL of luminol‒dissolved oxygen in the absence of additional oxidants. The mechanism study demonstrated that exfoliated MoS 2 NS could catalyze the decomposition of dissolved oxygen by virtue of its exposed active sites on the surface, generating increased reactive oxygen intermediates, which then oxidize luminol and produce intense CL emission. The proposed high-efficiency luminol CL system was then employed for the extremely sensitive identification of dopamine based on the quenching of CL by dopamine. The limit of detection (LOD) for dopamine can be as low as 2.07 nM. Besides, it also works well in the actual urine sample with good recoveries (99.6–100.6 %), confirming the practicability of the method. As a new type of CL catalyst, MoS 2 NS developed in this work are easy to obtain, simple to prepare and can be produced in large quantities, which lays a foundation for extending applicability of MoS 2 NS in the CL field, and provides a new idea for developing simple and highly sensitive CL sensing system. [Display omitted] • A simple and easily available catalyst was developed for luminol chemiluminescence. • High-efficiency chemiluminescence was achieved without extra oxidizing agents. • Ultrasensitive detection of dopamine was realized. • Successful application in urine samples with high spiking recoveries. [ABSTRACT FROM AUTHOR]

Polyelectrolyte complex nanoparticles with integrated advances of coacervate complexes and nanomaterials have attracted considerable attention as soft templates and functional nano‐carriers. Herein, a facile and robust strategy, namely electrostatic assembly directed polymerization (EADP), for efficient and scalable preparation of stable coacervate nanoparticles is presented. With homo‐polyelectrolyte PAA (polyacrylic acid) as template and out of charge stoichiometry, the cationic monomers are polymerized together with cross‐linkers, which creates coacervate nanoparticles featuring high stability against salt through one‐pot synthesis. The particle size can be tuned by varying the cross‐linker amount and salt concentrations during the polymerization and the composition of nanoparticles, as well as the corresponding properties can be regulated by combining different charged blocks from both strong and weak ionic monomers. The strategy can tolerate both high monomer concentrations and increased volume of up to l L, which is favorable for scaled‐up preparations. Moreover, the coacervate nanoparticles can be freeze‐dried to produce a product in powder form, which can be redispersed without any effect on the particle size and size distribution. Finally, the obtained nanoparticles loaded with enzyme and Au nanoparticles exhibit enhanced catalytic performance, demonstrating a great potential for exploring various applications of coacervate particles as soft and functional nano‐carriers. [ABSTRACT FROM AUTHOR]