Default mode network scaffolds immature frontoparietal network in cognitive development.

The default mode network (DMN) is a workspace for convergence of internal and external information. The frontal parietal network (FPN) is indispensable to executive functioning. Yet, how they interplay to support cognitive development remains elusive. Using longitudinal developmental fMRI with an n-back paradigm, we show a heterogeneity of maturational changes in multivoxel activity and network connectivity among DMN and FPN nodes in 528 children and 103 young adults. Compared with adults, children exhibited prominent longitudinal improvement but still inferior behavioral performance, which paired with less pronounced DMN deactivation and weaker FPN activation in children, but stronger DMN coupling with FPN regions. Children's DMN reached an adult-like level earlier than FPN at both multivoxel activity pattern and intranetwork connectivity levels. Intrinsic DMN-FPN internetwork coupling in children mediated the relationship between age and working memory-related functional coupling of these networks, with posterior cingulate cortex (PCC)-dorsolateral prefrontal cortex (DLPFC) coupling emerging as most prominent pathway. Coupling of PCC-DLPFC may further work together with task-invoked activity in PCC to account for longitudinal improvement in behavioral performance in children. Our findings suggest that the DMN provides a scaffolding effect in support of an immature FPN that is critical for the development of executive functions in children.

Bioinspired Optical Flexible Cellulose Nanocrystal Films with Strain-Adaptive Structural Coloration.

Recent advances of photonic crystals are driven to mechanical sensors and smart wearable devices; however, for chiral photonic cellulose nanocrystal (CNC) materials, vivid structural coloration and reversible mechanochromism like chameleon skin remain a big challenge. Here, we report a ternary co-assembly and post-UV-irradiation polymerization strategy to develop flexible and elastic CNC composite films, which, notably, have naked-eye-visible brilliant structural colors and stretching-induced color change covering a broad wavelength region at a moderate deformation (like skin). By adjusting the stretching, the film is designed as a smart skin to adapt to surrounding environments for camouflage. This work offers a universal strategy for constructing biomimic optically functional cellulose skins.

Synthesis of Spirocyclohexadienones via Palladium-Catalyzed Dearomatization of Dibenzoxaborins.

The development of Pd(II)-catalyzed dearomatization transformation of dibenzoxaborins with alkynes triggered by transmetalation from boron to palladium has been achieved, leading to the synthesis of spirocyclohexadienones, an important skeleton demonstrating potential biomedical utility. The [3 + 2] spiroannulation exhibits remarkable regioselectivity and broad substrate scope under mild reaction conditions. This methodology employs dibenzoxaborin as a substrate to establish the formal dearomatization of 2-phenylphenol, which poses a formidable energy barrier to the destruction of aromaticity.

Asymmetric [5+1] Annulation via C-H Activation/1,4-Rh Migration/Double Bond Shift Using a Transformable Pyridazine Directing Group.

N-Heterocycle-assisted C-H activation/annulation reactions have provided new concepts for the construction and transformation of azacycles. In this work, we disclose a [5+1] annulation reaction using a novel transformable pyridazine directing group (DG). The DG-transformable reaction mode led to the construction of a new heterocyclic ring accompanied by transformation of the original pyridazine directing group via a C-H activation/1,4-Rh migration/double bond shift pathway, affording the skeleton of pyridazino[6,1-b]quinazolines with a good substrate scope under mild conditions. Diverse fused cyclic compounds can be achieved by derivatization of the product. The asymmetric synthesis of the skeleton was also realized to afford the enantiomeric products with good stereoselectivity.

Excellent Uniformity and Properties of Micro-Meter Thick Lead Zirconate Titanate Coatings with Rapid Thermal Annealing.

Lead zirconate titanate (PZT) films have shown great potential in piezoelectric micro-electronic-mechanical system (piezo-MEMS) owing to their strong piezoelectric response. However, the fabrication of PZT films on wafer-level suffers with achieving excellent uniformity and properties. Here, we successfully prepared perovskite PZT films with similar epitaxial multilayered structure and crystallographic orientation on 3-inch silicon wafers, by introducing a rapid thermal annealing (RTA) process. Compared to films without RTA treatment, these films exhibit (001) crystallographic orientation at certain composition that expecting morphotropic phase boundary. Furthermore, dielectric, ferroelectric and piezoelectric properties on different positions only fluctuate within 5%. The relatively dielectric constant, loss, remnant polarization and transverse piezoelectric coefficient are 850, 0.1, 38 µC/cm2 and -10 C/m2, respectively. Both uniformity and properties have reached the requirement for the design and fabrication of piezo-MEMS devices. This broadens the design and fabrication criteria for piezo-MEMS, particularly for piezoelectric micromachined ultrasonic transducers.

RhodiumIII-catalyzed remote difunctionalization of arenes assisted by a relay directing group.

Rhodium-catalyzed diverse tandem twofold C-H bond activation reactions of para-olefin-tethered arenes have been realized, with unsaturated reagents such as internal alkynes, dioxazolones, and isocyanates being the coupling partner as well as a relay directing group which triggers cyclization of the para-olefin group under oxidative or redox-neutral conditions. The reaction proceeded via initial ortho-C-H activation assisted by a built-in directing group in the arene, and the ortho-incorporation of the unsaturated coupling partner simultaneously generated a relay directing group that allows sequential C-H activation at the meta-position and subsequent cyclization of the para-olefins. The overall reaction represents C-C or N-C difunctionalization of the arene with the generation of diverse 2,3-dihydrobenzofuran platforms. The catalytic system proceeded with good efficiency, simple reaction conditions, and broad substrate scope. The diverse transformations of the products demonstrated the synthetic utility of this tandem reaction.

Water-soluble carboxymethyl chitosan (WSCC)-modified single-walled carbon nanotubes (SWCNTs) provide efficient adsorption of Pb(ii) from water.

Nanocomposites play a key role in the removal of toxic metal(loid)s from environmental water. In this study, we investigated the adsorption capability of water-soluble carboxymethyl chitosan (WSCC)-modified functionally oxidized single walled carbon nanotubes (oSWCNTs) for rapid and efficient removal of toxic Pb(ii) from water. The WSCC-oSWCNTs nanocomposite was prepared by an acid treatment of SWCNTs followed by an ultrasonic dispersion process using WSCC as dispersant. The morphology and chemical characteristics of the WSCC-oSWCNTs nanocomposite were further identified using various characterization techniques (i.e., transmission electron microscopy, TEM; scanning electron microscopy, SEM; Raman spectra; Fourier transform infrared spectroscopy, FTIR; X-ray photoelectron spectroscopy, XPS; nitrogen adsorption-desorption isotherm test). The efficiency of the adsorption process in batch experiments was investigated via determining various factor effects (i.e. WSCC-oSWCNTs nanocomposite concentration, solution pH, initial Pb(ii) concentration, contact time, and reaction temperature). Kinetic results showed that the adsorption process followed a pseudo-second-order, while an isotherm results study showed that the adsorption process followed the Langmuir and Freundlich isotherm models at the same time. In addition, the van't Hoff equation was used to calculate thermodynamic parameters for assessing the endothermic properties and spontaneity of the adsorption process. The WSCC-oSWCNTs nanocomposite manifested a high adsorption capacity for Pb(ii) (113.63 mg g-1) via electrostatic interactions and ion-exchange, as its adsorption rate could reach up to 98.72%. This study, therefore, provides a novel adsorbent for the removal and detection of harmful residues (i.e. toxic metal(loid)s) from environmental water, such as industry wastewater treatment and chemical waste management.

Effective dispersion of oxidized multi-walled carbon nanotubes using a water-soluble N,O-carboxymethyl chitosan via non-covalent interaction.

Dispersible multi-walled carbon nanotubes (MWCNTs) in water have been widely applied in the nanotechnology field. This study reports a water-soluble N,O-carboxymethyl chitosan(N,O-CMCS) assisted individual dispersion of oxidized multi-walled carbon nanotubes (oMWCNTs) as a dispersant. First, the dispersing agent N,O-CMCS was successfully synthesized using the nucleophilic substitution of deacetylated chitosan with chloroacetic acid in an alkaline solution. It was further confirmed using Fourier transform infrared spectroscopy (FTIR). Second, after the treatment with the concentrated hydrochloric acid, the prepared oMWCNTs were dispersed in an aqueous solution of N,O-CMCS under ultrasonic vibrations. Finally, the dispersed aqueous solution was subjected to centrifugation to collect the supernatant of individually dispersed N,O-CMCS/oMWCNTs. In addition, transmission electron microscopy (TEM) further confirmed that the purity of oMWCNTs was improved after the acidification progress. Besides, the stability of the dispersion solution was evidenced by digital photos of oMWCNTs dispersed by N,O-CMCS before and after. Moreover, the UV-vis spectrum (the characteristic peak of dispersed oMWCNTs downshifted 13 nm) showed that the supernatant was enriched by the individual oMWCNTs. In particular, the analytical results of FTIR (the -NH2 band of N,O-CMCS downshifted 7 cm-1), resonance Raman spectroscopy (the I D/I G ratio of dispersed oMWCNTs only increased 0.14), and XRD identified the formation of a non-convalent interaction between N,O-CMCS and oMWCNTs. These findings reveal the dispersing nature of N,O-CMCS towards oMWCNTs in water media.

Achieving a Record-High Capacitive Energy Density on Si with Columnar Nanograined Ferroelectric Films.

High energy density dielectric film capacitors are desirable in modern electronic devices. Their miniaturization and integration into Si-based microsystems create opportunities for in-circuit energy supply, buffering, and conditioning. Here, we present a CMOS (complementary metal oxide semiconductor)-compatible route for the fabrication of BaTiO3 film capacitors on Si with a record-high recoverable energy density and good efficiency (∼242 J/cm3 and ∼76% at 8.75 MV/cm). These BaTiO3 films were sputter-deposited at 350 °C and consisted of slightly compressed superfine columnar nanograins with a (001) texture. Such a nanostructure was endowed with a high breakdown strength, a reduced remnant polarization, and an enhanced maximum polarization, which are accountable for their excellent energy storage performance. Moreover, these BaTiO3 film capacitors displayed a high electrical fatigue resistance, a wide range of operating temperatures, and an excellent frequency stability. With an engineered nanostructure, the prototype perovskite of BaTiO3 has shown great promise for capacitive energy storage applications.

Triazolotriazine-based thermally activated delayed fluorescence materials for highly efficient fluorescent organic light-emitting diodes (TSF-OLEDs).

Thermally activated delayed fluorescence (TADF) sensitized fluorescent organic light-emitting diodes (TSF-OLEDs) have shown great potential for the realization of high efficiency with low efficiency roll-off and good color purity. However, the superior examples of TSF-OLEDs are still limited up to now. Herein, a trade-off strategy is presented for designing efficient TADF materials and achieving high-performance TSF-OLEDs via the construction of a new type of triazolotriazine (TAZTRZ) acceptor. The enhanced electron-withdrawing ability of TAZTRZ acceptor, fused by triazine (TRZ) and triazole (TAZ) together, enables TADF luminogens with small singlet-triplet energy gap (ΔEST) values. Meanwhile, the increased planarity from the TRZ-phenyl linkage (6:6 system) to the TAZ-phenyl linkage (5:6 system) can compensate the decrease of oscillator strength (f) while lowing ΔEST, thus achieving a trade-off between small ΔEST and high f. As a result, the related TSF-OLED achieved an extremely low turn-on voltage of 2.1 V, an outstanding maximum external quantum efficiency (EQEmax) of 23.7% with small efficiency roll-off (EQE1000 of 23.2%; EQE5000 of 20.6%) and an impressively high maximum power efficiency of 82.1 lm W-1, which represents the state-of-the-art performance for yellow TSF-OLEDs.

High Energy Performance Ferroelectric (Ba,Sr)(Zr,Ti)O3 Film Capacitors Integrated on Si at 400 °C.

BaTiO3-based ferroelectrics have been extensively studied due to their large dielectric constants and a high saturated polarization, which have the potential to store or supply electricity of very high energy and power densities. In order to further improve the energy efficiency η and the recyclable energy density Wrec, an A, B-site co-doped (Ba0.95,Sr0.05)(Zr0.2,Ti0.8)O3 ceramic target was used for sputter deposition of film capacitor structures on Si. This film composition reduces the remnant polarization Pr, while the choice of a low-temperature, templated sputtering process facilitates the formation of high-density arrays of columnar nanograins (average diameter d ∼20 nm) and grain boundary dead layers. This self-assembled nanostructure further delays the saturation of the electric polarization, leading to a high energy density Wrec of ∼148 J/cm3 and a high energy efficiency η of ∼90%. Moreover, the (Ba0.95,Sr0.05)(Zr0.2,Ti0.8)O3 film capacitors retain their high energy storage performance in a broad range of working temperature (-175-300 °C) and operating frequency (1 Hz-20 kHz). They are also fatigue-free after up to 2 × 109 switching cycles. Our work provides a new method and a cost-effective processing route for the creation and integration of high-performance dielectric capacitors for energy storage applications.

Effects of different pesticides treatments on the nutritional quality of kiwifruit.

Pesticides are widely used in the process of kiwifruit growth to promote fruit expansion. This study was aimed to assess the effects of pesticides on the quality of kiwifruit by applying high and normal concentrations of forchlorfenuron (CPPU) and thidiazuron (TDZ) to "Xuxiang" (XX) green kiwifruit and "Jinyan" (JY) gold kiwifruit. Sixty kiwifruit trees were used to comprehensively evaluate the effects on the pulp and whole kiwifruit. In addition to the weight gain effect and basic physical-chemical properties (vitamin C, total protein, glucose and fructose, organic acids), the main nutritional qualities (in vitro and cellular antioxidant activity (CAA), and dietary minerals) were also evaluated. The vitamin C content of XX was not affected by pesticides, but the use of CPPU reduced vitamin C of JY pulp by 23% (p < 0.05). Pesticides did not reduce the antioxidant values of XX pulp in vitro but significantly reduced CAA values (32%-47%). In JY pulp, pesticides treatments had no significant effect on antioxidant values in vitro except that CPPU treatments significantly reduced the ferric reducing antioxidant power (FRAP) value by 21% (p < 0.05). Reasonable use of pesticides can effectively improve taste of kiwifruit, increasing kiwifruit weight and the content of certain nutrients. PRACTICAL APPLICATION: Based on observed changes in nutritional components, CPPU may be more suitable for XX while TDZ may be more suitable for JY. The significance of this study may affect kiwifruit farmers and ultimately help improve the sensory quality of kiwifruit.

First record of the tropical genus Rambutanura (Collembola: Neanuridae: Neanurinae) in Palearctic, with description of a new species from China.

Genus Rambutanura Deharveng, 1988 of subfamily Neanurinae is herein recorded and a new species is described from China. A key to the species of the whole world of the genus is provided. In order to determine the new species, a new diagnosis within the genus Rambutanura Deharveng, 1988 is proposed. The new species is distinguished from all known members of the genus by its unique set of morphological characters notably: 2+2 depigmented eyes, mandible quadridentate, presence of 1 additional s-chaeta on each tubercle Di from Th. I to Abd. IV, presence of 2 additional s-chaetae on tubercle Dl from Abd. I to Abd. V, presence of guard chaetae sgd and sgv on AOIII, absence of digitate body tubercles.

Demonstration of ultra-high recyclable energy densities in domain-engineered ferroelectric films.

Dielectric capacitors have the highest charge/discharge speed among all electrical energy devices, but lag behind in energy density. Here we report dielectric ultracapacitors based on ferroelectric films of Ba(Zr0.2,Ti0.8)O3 which display high-energy densities (up to 166 J cm-3) and efficiencies (up to 96%). Different from a typical ferroelectric whose electric polarization is easily saturated, these Ba(Zr0.2,Ti0.8)O3 films display a much delayed saturation of the electric polarization, which increases continuously from nearly zero at remnant in a multipolar state, to a large value under the maximum electric field, leading to drastically improved recyclable energy densities. This is achieved by the creation of an adaptive nano-domain structure in these perovskite films via phase engineering and strain tuning. The lead-free Ba(Zr0.2,Ti0.8)O3 films also show excellent dielectric and energy storage performance over a broad frequency and temperature range. These findings may enable broader applications of dielectric capacitors in energy storage, conditioning, and conversion.

[Experimental study on the anti-liver fibrosis effect of guzhang tablet in rats].

OBJECTIVE: To observe the anti-liver-fibrosis effect of Guzhang Tablet (GZT) and to explore its mechanism. METHODS: Fifty female rats, weighing 200-220 g were randomly divided into the blank control group, the model group, the small dosage GZT group, the large dosage GZT group and the Biejiajian Pill (BJJP) group, 10 rats in each group. The changes of related serum enzymes, liver-fibrosis marker, oxygen free radical and liver tissue pathology were observed after 8 weeks of treatment. RESULTS: (1) Compared with the model group, the serum levels of alanine transaminase (ALT), aspartate aminotransferase (AST), glutamyltranspetidase (GGT), alkaline phosphatase (AKP) were improved in the GZT groups, better effect was got in the large dosage GZT group. (2) Compared with the blank control group, GZT showed no effect on serum total protein (TP) but with raising albumin (ALB) effect. (3) Compared with blank control group, the levels of hyaluronidase (HA), laminin (LN), collagen type IV (IV-C) and procollagen type III (PC III) in both GZT groups were lower, especially in the large dosage GZT group. (4) Small and large dosage of GZT showed effect in reducing malonyldialdehyde (MDA), Glutathione-peroxidose(GSH-Px) and nitric oxide (NO) content, but the effect on increasing superoxide dismutase (SOD) similar to that of BJJP with no significant different. (5) GZT, both small and large dosage, had obvious anti-liver fibrosis action, which was superior to that of BJJP. CONCLUSION: In the genetic and developing processes of liver fibrosis in rats, GZT could protect the liver cells, inhibit the synthesis and reduce the content of collagens, the mechanism might be related with its action in antagonizing peroxidation injury, indicating that GZT could effectively prevent liver fibrosis formation.