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Ni-based catalysts have been considered as an efficient anode material for urea fuel cells due to their low cost and high activity in alkaline media. Ni2P/NiCo2S4 catalyst grown on nickel foam was synthesized by hydrothermal synthesis and solid phosphating. The cathode material Pt/C was prepared using the drop-coating method, which has good oxygen reduction reaction (ORR) activity. H-type urea/O2 fuel cell was assembled and showed high energy density in alkaline solution at room temperature. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) were employed to characterize the Ni2P/NiCo2S4/NF catalyst. Results confirmed the formation of 3D flower-like microspheres from Ni2P/NiCo2S4/NF catalyst nanosheets. Electrochemical testing results indicated that the Ni2P/NiCo2S4/NF catalyst-decorated electrode can effectively promote urea oxidation and plays a leading role in improving the performance of fuel cells in 1 M KOH + 0.33 M urea. The H-type urea/O2 fuel cell possesses a high power density of 0.42 mW cm−2 at a cell potential of 0.45 V. To summarize, this study introduces a cheap but efficient electrode material as an anode catalyst for constructing urea fuel cells. [ABSTRACT FROM AUTHOR]

To elucidate the variation characteristics of nitrogen (N), phosphorus (P), and potassium (K) content and accumulation in cotton at different yield levels, a two-year experiment was conducted using cotton variety Lumianyan 24 under four N treatments (506, 402.5, 299, and 195.5 kg ha−1, designated as N1, N2, N3, and N4, respectively). The four P and K fertilization ratios were (PK-M1, 25% P and K applied at squaring stage (SS) and 75% at the bloom-bolling stages (BS)), 50%:50% (PK-M2, 50% P and K applied at each stage), 75%:25% (PK-M3, 75% P and K applied at SS and 25% at the BS) and 100%:0% (PK-M4, total P and K applied at SS). The results showed that the N content (Nc), P content (Pc), and K content (Kc) of cotton plants at high yield levels were 23.3%, 44.2%, and 31.6% higher than those at low yield levels. In addition, the reproductive organs maintained higher Pc and Kc at high yield levels, and the Nc, Pc, and Kc exhibited positive linear correlations with yield, while Nc/Pc, Nc/Kc, and Kc/Pc had significant negative correlations with yield. In conclusion, seed cotton yield was mainly limited by Nc at low yield levels and affected by Pc and Kc at high yield levels. Then, when 0.85 < Nc/Kc < 1.0 at the full squaring stage (FS), 0.8 < Nc/Kc < 1.0 at the full flowering stage (FF), 4.3 < Nc/Pc < 6.7 at the early-full bolling stage (EFB) and 4.9 < Nc/Pc < 7.1 at the late-full bolling stage (LFB), there is a high yield potential of 7000–9000 kg ha−1. Furthermore, yields can be improved by reducing the application of N during the growing period and increasing the application of P fertilizer during the later growth period. [ABSTRACT FROM AUTHOR]

Magnetic hydroxyapatite nanocomposites are promising candidates for various biomedical applications. However, the uncontrolled growth with the unfavorable size limits their widespread utilization in real-time applications. Herein, a facile method was utilized to fabricate uniform spherical-shaped nanocomposites of manganese oxide combined hydroxyapatite (Mn 3 O 4 -HAp) with an average size of about 28 nm. The structural characterization reveals the presence of Mn 3 O 4 in the crystalline phase, confined by HAp to give a composite structure. The biocompatibility and drug loading capability of Mn 3 O 4 -HAp nanocomposites are improved by surface modification using Food and Drug Administration-approved triblock copolymer Pluronic® F-127, followed by folic acid (FA) for targeting ability. Taking advantage of the surface properties of the polymer and the drug delivery potential of HAp, metformin was encapsulated in the prepared nanocomposites with a loading capacity of 98 %. The prepared nanocomposites indicate promising cell viability up to 87 % and an excellent drug release profile in an acidic atmosphere. Moreover, the magnetic component Mn 3 O 4 presents auspicious T 1 -Magnetic resonance imaging with notable r 1 relaxivity of 2.166 mM−1s−1. Further, the Mn 3 O 4 -HAp@PF127-FA-drug nanocomposites demonstrate good cellular uptake and excellent reactive oxygen species (ROS) production under low-intensity UV irradiation, resulting in a remarkable photodynamic therapeutic effect. The results showed that the designed Mn 3 O 4 -HAp nanocomposites are promising targeted chemo-theranostic agents. [Display omitted] [ABSTRACT FROM AUTHOR]

Eukaryotic cells extend a variety of surface protrusions to direct cell motility. Formation of protrusions is mediated by coordinated actions between the plasma membrane and the underlying actin cytoskeleton. Here, we found that the single calponin homology (CH) domain-containing protein CHDP-1 induces the formation of cell protrusions in C. elegans. CHDP-1 is anchored to the cortex through its amphipathic helix. CHDP-1 associates through its CH domain with the small GTPase Rac1/CED-10, which is a key regulator of the actin cytoskeleton. CHDP-1 preferentially binds to the GTP-bound active form of the CED-10 protein and preserves the membrane localization of GTP-CED-10. Hence, by coupling membrane expansion to Rac1-mediated actin dynamics, CHDP-1 promotes the formation of cellular protrusions in vivo. [ABSTRACT FROM AUTHOR]

Advances in contrast agents have greatly enhanced the sensitivity of magnetic resonance imaging (MRI) technique for early diagnosis of cancer. However, the commercial superparamagnetic iron oxide nanoparticles (SPION)-based contrast agents synthesized by co-precipitation method are not monodisperse with irregular morphologies and ununiform sizes. Other reported SPION-based contrast agents synthesized by solvothermal method or thermal decomposition method are limited by the bad water-dispersibility and low specificity to cancer cells. Herein, we propose a new strategy for exploring SPION-based MRI contrast agents with excellent water-dispersibility and high specificity to cancer cells. The SPION was synthesized by a polyol method and then entrapped into albumin nanospheres (AN). After that, a ligand folic acid (FA) was conjugated onto the surface of the AN to construct a SPION-AN-FA composite. The transmission electron microscope (TEM) and dynamic light scattering (DLS) results indicate that the SPION-AN-FA has a spherical shape, a uniform size and an excellent water-dispersibility (polydispersity index (PDI) <0.05). The results of laser scanning confocal microscope (LSCM) and flow cytometry demonstrate that the SPION-AN-FA nanoparticles are highly specific to MCF-7 and SPC-A-1 cells due to the recognition of ligand FA and folate receptor α (FRα). The r 2 / r 1 value of SPION-AN-FA is around 40, which is much higher than that of Resovist ® indicating that our SPION-AN-FA has a stronger T 2 shortening effect. The T 2 -weighted images of MCF-7 cells incubated with SPION-AN-FA are significantly darker than those of MCF-7 cells incubated with AN, indicating that our SPION-AN-FA has a strong MR imaging efficacy. In view of the excellent water-dispersibility, the high specificity to cancer cells and the strong MR imaging efficacy, our SPION-AN-FA can be used as a negative MR contrast agent. [ABSTRACT FROM AUTHOR]

Highlights: [•] An improved double emulsion technology with in situ reaction of lysine (Lys) and glutaraldehyde (GA) to fabricate autofluorescent PLGA microcapsules. [•] A novel ultrasonic/fluorescent dual-modality contrast agents without conjugation to any fluorescent agent. [•] This reaction product Lys-GA is found to exhibit bright and stable autofluorescence. [•] The integration of the autofluorescence into ultrasonic contrast agent of PLGA microcapsules. [Copyright &y& Elsevier]

The smartphone-based colorimetric sensor, which is based on anti-aggregation mechanism of polyvinylpyrrolidone (PVP) modified silver nanoparticles (PVP-AgNPs) in the presence of Pb2+, for high-performance colorimetric detection of PPi with excellent selectivity. • A new strategy for PPi determination with a smartphone-based colorimetric sensor. • The selectivity of the smartphone-based colorimetric sensor for PPi detection is excellent. • The colorimetric sensor exhibits high sensitivity with detection limits of 0.2 μM by smartphone analysis and 1.0 μM by naked-eyes. Monitoring pyrophosphate (PPi) in food is still a challenge due to lack of ultrasensitive, rapid, and selective analysis techniques. Herein, a smartphone-based colorimetric sensor based on anti-aggregation of polyvinylpyrrolidone (PVP) modified silver nanoparticles caused by Pb2+ is reported, which lead to a color change from blue to yellow for accurate and reliable detection of PPi in water and canned meat. The smartphone-based colorimetric sensor exhibits high sensitivity with detection limits of 1.0 μM by naked-eyes and 0.2 μM by smartphone analysis. Confirmatory analysis indicates that the proposed smartphone-based colorimetric sensor exhibits feasibility and real time performance for PPi detection in real food samples. The first-principles calculations at the PBE/DNP + level indicate that the Gibbs free energy (ΔG) of the interaction between PPi and Pb2+ is much higher than that between PVP and Pb2+, which effectively verified the anti-aggregation detection mechanism. This study provides a meaningful design strategy for the development of novel colorimetric sensors in the future. [ABSTRACT FROM AUTHOR]

The accurate assessment of nitrogen (N) status is important for N management and yield improvement. The N status in plants is affected by plant densities and N application rates, while the methods for assessing the N status in drip-irrigated cotton under reduced nitrogen treatment and different plant densities are lacking. Therefore, this study was conducted with four different N treatments (195.5, 299, 402.5, and 506 kg N ha−1) and three sowing densities (6.9 × 104, 13.8 × 104, and 24 × 104 plants ha−1) by using a low-cost Unmanned Aerial Vehicle (UAV) system to acquire RGB imagery at a 10 m flight altitude at cotton main growth stages. We evaluated the performance of different ground resolutions (1.3, 2.6, 5.2, 10.4, 20.8, 41.6, 83.2, and 166.4 cm) for image textures, vegetation indices (VIs), and their combination for leaf N concentration (LNC) estimation using four regression methods (stepwise multiple linear regression, SMLR; support vector regression, SVR; extreme learning machine, ELM; random forest, RF). The results showed that combining VIs (ExGR, GRVI, GBRI, GRRI, MGRVI, RGBVI) and textures (VAR, HOM, CON, DIS) yielded higher estimation accuracy than using either alone. Specifically, the RF regression models had a higher accuracy and stability than SMLR and the other two machine learning algorithms. The best accuracy (R2 = 0.87, RMSE = 3.14 g kg−1, rRMSE = 7.00%) was obtained when RF was applied in combination with VIs and texture. Thus, the combination of VIs and textures from UAV images using RF could improve the estimation accuracy of drip-irrigated cotton LNC and may have a potential contribution in the rapid and non-destructive nutrition monitoring and diagnosis of other crops or other growth parameters. [ABSTRACT FROM AUTHOR]

Porous poly (lactic acid) (PLA)-based scaffolds have been widely used as a promising product in tissue engineering. However, it is still a challenge to prepare the PLA-based scaffolds with high expansion ratio, good hydrophilicity, and excellent cytocompatibility by a green and cost-effective fabrication approach. Herein, we prepared porous PLA-based scaffolds using carbon dioxide (CO 2) as the physical foaming agent. To improve the hydrophilicity and foaming behavior of PLA, poly (ethylene glycol) (PEG) was selected as a good additive to blend with PLA. It revealed that the introduction of PEG could improve the foaming behavior of PLA and promote the formation of opening cells via reducing the matrix strength of PLA. The obtained 3D PLA/PEG scaffolds exhibited high expansion ratio (9.1), high open-cell content (95.2%), and super-hydrophilicity (water contact angle 0°). Additionally, the mouse fibroblast NIH/3T3 cells with live/dead cell fluorescence staining assay was utilized to examine the biocompatibility of PLA/PEG scaffolds. The result demonstrated that the proliferation ratio of NIH/3 T3 cells on the surface of PLA/PEG scaffolds was higher than that of PLA scaffolds, indicating that the highly interconnected cell structure was conducive to cell adhesion and attachment. Consequently, such hydrophilic open-cell structure obtained by adding PEG into PLA possesses great potential for use in tissue engineering. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: From a genome-scale genetic screen, we have identified 114 lithium-sensitive and 6 lithium-tolerant gene mutations in Saccharomyces cerevisiae. Twenty-five of these identified lithium-sensitive mutations are of genes previously reported to be involved in sporulation and meiosis, whereas thirty-six of them are of genes involved in the vacuolar protein sorting (VPS) pathway, mainly functioning in the membrane docking and fusion. Accordingly, the lithium-sensitive phenotypes for one third of identified VPS mutants well correlate to their intracellular lithium contents in response to lithium stress. This indicates the integrity of the VPS pathway is critic for the ion homeostasis in yeast cells. The halotolerant protein kinase Hal5p, a regulator of the potassium transporter Trk1p, is shown to be the high-copy suppressor of nearly one third of identified lithium-sensitive mutations of genes involved in the sporulation and meiosis as well as in the biosynthesis of ergosterol. These results suggest that Hal5p-mediated ion homeostasis is important for these two biological processes. [Copyright &y& Elsevier]

Elucidating the chromatin dynamics that orchestrate embryogenesis is a fundamental question in developmental biology. Here, we exploit position effects on expression as an indicator of chromatin activity and infer the chromatin activity landscape in every lineaged cell during Caenorhabditis elegans early embryogenesis. Systems‐level analyses reveal that chromatin activity distinguishes cellular states and correlates with fate patterning in the early embryos. As cell lineage unfolds, chromatin activity diversifies in a lineage‐dependent manner, with switch‐like changes accompanying anterior–posterior fate asymmetry and characteristic landscapes being established in different cell lineages. Upon tissue differentiation, cellular chromatin from distinct lineages converges according to tissue types but retains stable memories of lineage history, contributing to intra‐tissue cell heterogeneity. However, the chromatin landscapes of cells organized in a left–right symmetric pattern are predetermined to be analogous in early progenitors so as to pre‐set equivalent states. Finally, genome‐wide analysis identifies many regions exhibiting concordant chromatin activity changes that mediate the co‐regulation of functionally related genes during differentiation. Collectively, our study reveals the developmental and genomic dynamics of chromatin activity at the single‐cell level. SYNOPSIS: This study investigates the influence of local chromatin environment on reporter gene expression during Caenorhabditis elegans embryogenesis, based on single‐cell lineage tracing and live‐cell imaging. The chromatin activity landscape is inferred in lineage‐resolved single cells during C. elegans early embryogenesis.Chromatin activity diversifies in a lineage‐dependent manner, accompanying lineage fate commitment and anterior‐posterior fate asymmetry.Chromatin activity converges on tissue‐specific states but retains memories of lineage origins that contribute to cell heterogeneity within tissues.Predetermination of analogous chromatin activity occurs in early progenitor cells during left‐right symmetry establishment. [ABSTRACT FROM AUTHOR]

One big challenge with active targeting of nanocarriers is non-specific binding between targeting molecules and non-target moieties expressed on non-cancerous cells, which leads to non-specific uptake of nanocarriers by non-cancerous cells. Here, we propose a novel Trojan-horse targeting strategy to hide or expose the targeting molecules of nanocarriers on-demand. The non-specific uptake by non-cancerous cells can be reduced because the targeting molecules are hidden in hydrophilic polymers. The nanocarriers are still actively targetable to cancer cells because the targeting molecules can be exposed on-demand at tumor regions. Typically, Fe 3 O 4 nanocrystals (FN) as magnetic resonance imaging (MRI) contrast agents were encapsulated into albumin nanoparticles (AN), and then folic acid (FA) and pH-sensitive polymers (PP) were grafted onto the surface of AN-FN to construct PP-FA-AN-FN nanoparticles. Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), transmission electron microscope (TEM) and gel permeation chromatography (GPC) results confirm successful construction of PP-FA-AN-FN. According to difference of nanoparticle-cellular uptake between pH 7.4 and 5.5, the weight ratio of conjugated PP to nanoparticle FA-AN-FN (i.e. graft density) and the molecular weight of PP (i.e. graft length) are optimized to be 1.32 and 5.7 kDa, respectively. In vitro studies confirm that the PP can hide ligand FA to prevent it from binding to cells with FRα at pH 7.4 and shrink to expose FA at pH 5.5. In vivo studies demonstrate that our Trojan-horse targeting strategy can reduce the non-specific uptake of the PP-FA-AN-FN by non-cancerous cells. Therefore, our PP-FA-AN-FN might be used as an accurately targeted MRI contrast agent. [ABSTRACT FROM AUTHOR]

Inorganic photosensitizer coupled Gd-based upconversion luminescent (UCL) nanocomposites have potential application for both magnetic resonance imaging (MRI) and photodynamic therapy (PDT) of cancers using the light stability and biocompatibility of TiO 2 inorganic photosensitizer. However, TiO 2 inorganic photosensitizer could only be excited by ultraviolet (UV) light, which was harmful and weakly penetrable in tissues. In this work, folic acid (FA)-targeted NaGdF 4 :Yb/Tm@SiO 2 @TiO 2 nanocomposites (FA-Gd-Si-Ti NPs) were constructed and synthesized for both in vivo MRI and near infrared (NIR)-responsive inorganic PDT, in which TiO 2 component could be excited by NIR light due to the UCL performance of NaGdF 4 :Yb/Tm component converting NIR to UV light. The results showed the as-prepared FA-Gd-Si-Ti NPs had good biocompatibility in vitro and in vivo. Moreover, MR study indicated that FA-Gd-Si-Ti NPs were good T 1 -weighted MRI contrast agents with high longitudinal relaxivity (r 1 ) of 4.53 m m −1 s −1 , also in vivo MRI of nude mice showed “bright” signal in MCF-7 tumor. Under the irradiation of 980 nm laser at the power density of 0.6 W/cm 2 for 20 min, the viability of HeLa and MCF-7 cells incubated with FA-Gd-Si-Ti NPs could decrease from about 90 % to 35 % and 31%, respectively. Furthermore, in vivo PDT of MCF-7 tumor-bearing nude mice model showed that the inhibition ratio of tumors injected with FA-Gd-Si-Ti NPs reached up to 88.6% after 2-week treatment, compared with that of nude mice in control group. Based on the deep penetration of NIR light and the good biocompatibility of TiO 2 inorganic photosensitizer, the as-prepared FA-Gd-Si-Ti NPs could have potential applications in both MRI and NIR-responsive PDT of cancers in deep tissues. [ABSTRACT FROM AUTHOR]