Recently, resting functional MRI has provided invaluable insight into the brain developmental processes of early infancy and childhood. A common feature of previous functional development studies is ...the use of age to separate subjects into different cohorts for group comparisons. However, functional maturation paces vary tremendously from subject to subject. Since this is particularly true for the first years of life, an alternative to physical age alone is needed for cluster analysis. Here, a data-driven approach based on individual brain functional connectivity was employed to cluster typically developing children who were longitudinally imaged using MRI without sedation for the first two years of life. Specifically, three time periods were determined based on the distinction of brain functional connectivity patterns, including 0–1 month (group 1), 2–7 months (group 2), and 8–24 (group 3) of age, respectively. From groups 1 to 2, connection density increased by almost two-fold, local efficacy (LE) is significantly improved, and there was no change in global efficiency (GE). From groups 2 to 3, connection density increased slightly, LE showed no change, and a significant increase in GE were observed. Furthermore, 27 core brain regions were identified which yielded clustering results that resemble those obtained using all brain regions. These core regions were largely associated with the motor, visual and language functional domains as well as regions associated with higher order cognitive functional domains. Both visual and language functional domains exhibited a persistent and significant increase within domain connection from groups 1 to 3, while no changes were observed for the motor domain. In contrast, while a reduction of inter-domain connection was the general developmental pattern, the motor domain exhibited an interesting “V” shape pattern in its relationship to visual and language associated areas, showing a decrease from groups 1 to 2, followed by an increase from groups 2 to 3. In summary, our results offer new insights into functional brain development and identify 27 core brain regions critically important for early brain development.
Characterizing functional development of the human brain is of critical importance. With an improved understanding of the functional maturation processes, assessing and monitoring the normal and ...abnormal brain development are feasible. The ultimate goal of this dissertation was to provide novel insights into early brain functional development.Three major achievements have been accomplished. First, we found that brain functional development could be separated into three distinct stages in the first two years of life. Specifically, from stages 1 to 2, the connection density increases by almost two-fold, local efficiency is significantly improved, and there is no change in global efficiency. From stages 2 to 3, connection density increases slightly, local efficiency shows no change, and a significant increase in global efficiency is observed. In addition, 27 core regions are identified which yield clustering results that resemble those obtained using all brain regions.Second, we delineated the development of brain functional integration by computing participation coefficients. Improved functional integration was uncovered after 12 months of age. The spatiotemporal distribution of the brain diverse clubs was also revealed. Comparing with the adult result, low spatial overlapping ratios (~25%) were observed in infant groups. Nevertheless, posterior cingulate cortex, amygdala, hippocampus, and fusiform area have been consistently observed in infants and adults, suggesting the critical role of these regions for functional integration starting from birth.Finally, we delineated the emergency of a functionally flexible brain during early infancy. Continually increased flexibility was found in whole brain, high-order brain functional networks and motor network, while a temporally stable pattern was observed in visual networks. Moreover, visual network functional flexibility at 3 months of age was significantly associated with the behavioral performance measured at 5/6 years of age. We further termed the brain regions with the highest 10% flexibility as the "flexible club", and compared these regions with hubs and diverse clubs to uncover their unique functional roles.In conclusion, our results provide important brain developmental patterns during the first two years of life. These findings fill the gaps on brain functional development, and may shed new light on the underlying processes of brain maturation.
The development of rare earth adsorbents with high adsorption capacity, outstanding selectivity, and excellent reusability is important for the enrichment and recovery of rare earth elements. The ...adsorption of the rare earth ion Gd(III) by a phosphorylated polyacrylonitrile fiber was investigated. In this work, the adsorbent was synthesized by a simple and cost-effective grafting method using polyacrylonitrile (PAN) fibers as the substrates. The FTIR analysis, SEM, XPS, and TGA indicated the successful synthesis of polyacrylonitrile-phosphite (PAN-Phos) fibers. To evaluate the feasibility of PAN-Phos fibers as the potential adsorbents for Gd(III) removal, a series of adsorption experiments were conducted. The pseudo-second-order kinetic model better illustrated the adsorption of Gd(III) on PAN-Phos fibers, and equilibrium adsorption was achieved within 50 min; the maximum adsorption capacity was 120.9 mg·g–1. The PAN-Phos fibers also exhibited excellent reproducibility after four adsorption cycles. In addition, the results of various analyses indicated that the adsorption mechanism of Gd(III) on PAN-Phos fibers was mainly through the synergistic complexation of secondary amine and phosphoric acid groups. It provided a practicable way for the synthesis and preparation of rare earth adsorbent materials.
Hydrophobic and oleophilic biomass-based block materials are considered to be highly promising candidates used for oil/water separation. However, the crucial hydrophobic modification process often ...involves various toxic and hazardous organic substances or requires high energy inputs. Inspired by the flame retardant principle of phosphorus-containing flame retardants, herein, an Enteromorpha-derived carbon (ADP-EP) aerogel with a water contact angle of 144.2° was prepared by successive freeze-shaping, freeze-drying and low-temperature carbonization treatment (300 °C), using NH
H
PO
(ADP) as a modifier. The results demonstrated that the introduction of NH
H
PO
could largely facilitate the removal of oxygenated groups from the pristine EP aerogels and enhance their surface roughness, thereby achieving surface hydrophobic modification. Featuring intrinsic low density, rich porosity and strong lipophilicity, the as-fabricated ADP-EP aerogels exhibited exceptional performance in both oil spill adsorption (~140 g/g) and water-in-oil emulsion separation. Moreover, the good reusability for oil uptake was also realized thanks to its robust mechanical compressibility and thermal stability. This work provides a facile, economical and eco-friendly route to obtain a desirable hydrophobic/oleophilic surface.
We report a new, effective and environmentally friendly protocol for selective aerobic oxidative coupling of arylboronic acids with carboxylic anhydrides in the presence of ligand-free palladium ...catalyst. The aryl benzoates are obtained in good to excellent yields.
Two different terminal alkynes now can be coupled together in the presence of NiCl(2).6H(2)O/CuI by using an excess of one of the terminal alkyne substrates. The new method employed 20 mol % TMEDA as ...the ligand and environmentally benign O(2) or air as the oxidant. It is the first example using Ni-salt as catalyst by employing air or O(2) as oxidant, which led to efficient heterocoupling of two different alkynes.
In the mol-ecule of the title compound, C(10)H(10)N(4)OS, the configuration about the C=N double bond is E. The dihedral angle between the thia-diazole and benzene rings is 81.1 (1)°. In the crystal, ...mol-ecules are linked by N-H⋯N and C-H⋯O hydrogen bonds to form a two-dimensional network parallel with the bc plane.
In the title compound, C(14)H(10)Cl(2)N(2)O(2), the configuration about the C=N double bond is E and the dihedral angle between the benzene rings is 1.75 (5)°. An intra-molecular N-H⋯O inter-action ...generates an S(6) ring. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, resulting in 101 chains.
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