Ultrastable, Superrobust, and Recyclable Supramolecular Polymer Networks.

Supramolecular polymer networks (SPNs), crosslinked by noncovalent bonds, have emerged as reorganizable and recyclable polymeric materials with unique functionality. However, poor stability is an imperative challenge faced by SPNs, because SPNs are susceptible to heat, water, and/or solvents due to the dynamic and reversible nature of noncovalent bonds. Herein, the design of a noncovalent cooperative network (NCoN) to simultaneously stabilize and reinforce SPNs is reported, resulting in an ultrastable, superrobust, and recyclable SPN. The NCoN is constructed by multiplying the H-bonding sites and tuning the conformation/geometry of the H-bonding segment to optimize the multivalence cooperativity of H-bonds. The rationally designed H-bonding segment with high conformational compliance favors the formation of tightly packed H-bond arrays comprising higher-density and stronger H-bonds. Consequently, the H-bonded crosslinks in the NCoN display a covalent crosslinking effect but retain on-demand dynamics and reversibility. The resultant ultrastable SPN not only displays remarkable resistance to heat up to 120 °C, water soaking, and a broad spectrum of solvents, but also possesses a superhigh true stress at break (1.1 GPa) and an ultrahigh toughness (406 MJ m-3 ). Despite the covalent-network-like stability, the SPN is recyclable through activating its reversibility in a high-polarity solvent heated to a threshold temperature.

Segmental Abnormalities of White Matter Microstructure in Primary Hypothyroidism Identified by Automated Fiber Quantification.

INTRODUCTION: Hypothyroidism leads to impaired white matter (WM) integrity, associated with cognitive/neuropsychiatric dysfunction. However, the specific segmental abnormalities of the fibers remain unexplored. Therefore, this study aimed to investigate whether the damage of the WM is limited to a specific segment or the entire bundle via diffusion metrics using automated fiber quantification. METHODS: A cross-sectional study was conducted on 31 hypothyroid patients and 28 healthy controls. Thyroid-related hormone levels, cognitive/neuropsychiatric function, and diffusion tensor image data were collected and analyzed. Correlation and random forest analyses were also performed. RESULTS: The mean fractional anisotropy (FA) values were reduced at the fiber tract level. The mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) values were increased in several fiber tracts, i.e., cingulum cingulate (CC), anterior forceps of corpus callosum (CCF_A). Significant correlations were found between cognitive function and diffusion indicators such as the FA value of the left corticospinal tract and arcuate fasciculus (AF), the MD value of left CC, the RD value of left AF, the AD value of left CC, and CCF_A. The widespread microstructure disruption was spread on multiple specific segments of different tracts at the point-wise level. The random forest revealed that the accuracy of recognizing hypothyroid patients was 82.5%, with the anterior component of CCF_A having the most significant contribution. CONCLUSION: WM microstructural integrity impairments were found in multi-segments of the multiple fiber bundles in hypothyroidism, which might be a potential mechanism of the underlying neurocognitive decline and cerebral impairment. The CCF_A might serve as a neuro biomarker for early warning of cerebral impairment in hypothyroidism.

Altered thalamic functional connectivity and cerebral blood flow in insomnia disorder: a resting-state functional magnetic resonance imaging study.

BACKGROUND AND PURPOSE: The thalamus plays a crucial role in sleep regulation, but few studies have examined functional connectivity of the thalamus in insomnia disorder. This study aimed to investigate the connectivity patterns and perfusion of the thalamus in patients with insomnia disorder using resting-state functional connectivity and three-dimensional arterial spin labeling (3D ASL). MATERIALS AND METHODS: In total, 56 patients with insomnia disorder and 59 healthy control participants with a similar age-, gender-, and education lever distribution underwent resting-state functional magnetic resonance imaging (rs-fMRI) and 3D-ASL. The thalamus was selected as the seed region. Whole-brain connectivity was assessed using rs-fMRI. Cerebral blood flow (CBF) of the bilateral thalamus was measured with 3D-ASL using region-of-interest (ROI) analysis. All participants completed a series of neuropsychological assessments. Sleep parameters were assessed via polysomnography (PSG). The relationships between imaging parameters and clinical variables were assessed with Pearson correlation analysis. RESULTS: Compared with healthy controls, patients with insomnia disorder exhibited increased connectivity between the left thalamus and right precentral gyrus, and right thalamus and left middle frontal gyrus (MFG), right superior parietal lobule (SPL) and right superior frontal gyrus (SFG). Whereas decreased connectivity was noted between the right thalamus and left posterior cerebellar lobe including Crus I, Crus II, and VII b/VII. Connectivity between the right thalamus and left Crus I was positively correlated with MoCA scores (r = 0.286, P = 0.036) in insomnia disorder. CONCLUSIONS: Our findings illustrate functional abnormalities in brain connectivity and their relationship with cognitive impairments in insomnia disorder, providing novel insight into the neural mechanisms of insomnia disorder.

Microwave plasma rapid heating towards robust cathode/electrolyte interface for solid oxide fuel cells.

Mixed electronic and ionic conductivity (MIEC) perovskite oxides hold promise as cathode with high oxygen reduction reaction (ORR) activity for solid oxide fuel cells (SOFCs) operating at reduced temperatures. However, these MIEC cathodes usually contain lanthanide or alkaline-earth elements at A-site. These elements tend to interact with yttria-stabilized zirconia electrolyte (YSZ) to form unwanted phases such as La2Zr2O7 and SrZrO3 at conventional electrode fabrication conditions (>800 °C). Such unwanted interfacial reaction severely degrades the cell performance. We present a new method to assemble SrCo0.4Fe0.5W0.1O3-δ (SCFW) directly onto YSZ by a highly efficient microwave plasma technique. Intimate contact between SCFW and YSZ phases can be achieved by ten-minute microwave-plasma treatment with no new phase formation. Consequently, the microwave-plasma fabricated interface exhibits a notably high ORR performance, showing an area-specific resistances of 0.11 Ω cm2 at 600 °C, about two orders of magnitude better than the equivalent prepared via the conventional method. Our method is also effective in assembling other MIEC perovskite cathodes such as SrCo0.5Fe0.5O3-δ and SrCo0.8Nb0.1Ta0.1O3-δ on YSZ electrolyte, achieving notable enhancement of the cathode performance. This study thus provides an effective and convenient method for synthesizing reactive and robust interfaces between two incompatible phases with minimized interphase interactions.

Ultra-dispersed nickel-cobalt sulfides on reduced graphene oxide with improved power and cycling performances for nickel-zinc batteries.

Rechargeable alkaline nickel-zinc (Ni-Zn) batteries are attracting increased attention owing to their exceptional inherent safety and high specific capacity. Unfortunately, the limited power and cycling performances of these Ni-Zn batteries are still challenging. Herein, bimetal nickel-cobalt sulfide/ reduced graphene oxide (NiCo-S/RGO) composites with tunable compositions are synthesized by rational designing precursor and subsequent sulfidation treatment. NiCo-S is evenly anchored on RGO surface, resulting in increased number of electrochemical active sites, accelerated electrolyte ion diffusion, and enhanced electrical conductivity. Particularly, by tuning the Ni and Co composition ratios in NiCo-S, NiCo-S/RGO with a Ni to Co ratio of 2:1 (NiCo-S-2/RGO) shows a specific capacity of 145.7 mA h g-1 at 1 A g-1 and long-life cycling retention of 84.7% after 1000 cycles, and the above performances are superior than the controlled samples with other Ni to Co ratios. Furthermore, the as-assembled alkaline zinc batteries of NiCo-S-2/RGO//Zn deliver an impressive specific energy of 333.2 W h kg-1, showing great potential in practical applications. This experiment hopefully provides new idea for construction of high-performance electrodes of aqueous rechargeable batteries.

Intraspinal bronchogenic cyst: Series of case reports and literature review.

PURPOSE: Spinal bronchogenic cysts (SBCs) are rare congenital lesions. The clinical and imaging characteristics and treatment of SBCs are not well known. We studied three cases of SBCs retrospectively, which were registered in our department and analyzed eight case reports which were all published in English, focusing on providing a deeper knowledge of SBCs. METHODS: Three patients with SBCs registered in our department were retrospectively reviewed. Eight reported SBCs cases published from 1992 to 2015 were enrolled in our study. Imaging diagnosis was confirmed by computed tomography (CT), MRI, and computed tomography angiography (CTA). All of our patients and reviewed cases had undergone surgical resection and the final diagnosis was made by pathological examination. RESULTS: Five lesions were located at the cervical spinal canal. Most patients presented with pain in the limbs and back, which might be related to compression of the spinal cord and the reduced blood supply of the anterior spinal artery. The signal intensity on MRI was correlated with cystic fluid traits to a large extent. Seven lesions were partially removed because of the adhesions to the nearby spinal cord. All reported cases had no recurrence in the later follow-up. CONCLUSIONS: SBCs can occur anywhere in the spinal canal, but they are more likely to present at the cervical canal and might be present along with some developmental malformations of the spine. We emphasize the role of CT and MRI findings in the disease diagnosis. It is recommended that the lesion should be removed as completely as possible.

Abnormal structure and functional connectivity of the anterior insula at pain-free periovulation is associated with perceived pain during menstruation.

Neuroimaging studies have demonstrated the critical role of the insula in pain pathways and its close relation with the perceived intensity of nociceptive stimuli. We aimed to identify the structural and functional characteristics of the insula during periovulatory phase in women with primary dysmenorrhea (PDM), and further investigate its association with the intensity of perceived pain during menstruation. Optimized voxel-based morphometry and functional connectivity (FC) analyses were applied by using 3-dimensional T1-weighted and resting functional magnetic resonance imaging (fMRI) in 36 patients at the peri-ovulation phase and 29 age-, education-, and gender-matched healthy controls (HC). A visual analogue scale (VAS) was used to examine the intensity of the abdominal pain at periovulation and menstruation. In our results, PDM patients had significant higher VAS-rating during menstruaion than periovulation. Compared with the HC, PDM patients had lower gray matter density in the left anterior insula (aINS). Taken the left aINS as a seed region, we further found hypoconnectivity between aINS and medial prefrontal cortex (mPFC), which showed negative relation with the VAS during menstruation. As the aINS is a key site of the salience network (SN) and the mPFC is a critical region in the default mode network (DMN), it's implicated a trait-related central-alteration that communications between pain attention and perception networks were disrupted without the ongoing menstrual pain. Moreover, result of correlation analysis, at least in part, suggested a possible role of altered FC (pain-free period) in predicting pain perception (menstruation).

Low-Temperature Synthesis of Hierarchical Amorphous Basic Nickel Carbonate Particles for Water Oxidation Catalysis.

Amorphous nickel carbonate particles are catalysts for the oxygen evolution reaction (OER), which plays a critical role in the electrochemical splitting of water. The amorphous nickel carbonate particles can be prepared at a temperature as low as 60 °C by an evaporation-induced precipitation (EIP) method. The products feature hierarchical pore structures. The mass-normalized activity of the catalysts, measured at an overpotential of 0.35 V, was 55.1 A g(-1) , with a Tafel slope of only 60 mV dec(-1) . This catalytic activity is superior to the performance of crystalline NiOx particles and ß-Ni(OH)2 particles, and compares favorably to state-of-the-art RuO2 catalysts. The activity of the amorphous nickel carbonate is remarkably stable during a 10 000 s chronoamperometry test. Further optimization of synthesis parameters reveals that the amorphous structure can be tuned by adjusting the H2 O/Ni ratio in the precursor mixture. These results suggest the potential application of easily prepared hierarchical basic nickel carbonate particles as cheap and robust OER catalysts with high activity.

Nitrogen-doped graphene for generation and evolution of reactive radicals by metal-free catalysis.

N-Doped graphene (NG) nanomaterials were synthesized by directly annealing graphene oxide (GO) with a novel nitrogen precursor of melamine. A high N-doping level, 8-11 at. %, was achieved at a moderate temperature. The sample of NG-700, obtained at a calcination temperature of 700 °C, showed the highest efficiency in degradation of phenol solutions by metal-free catalytic activation of peroxymonosulfate (PMS). The catalytic activity of the N-doped rGO (NG-700) was about 80 times higher than that of undoped rGO in phenol degradation. Moreover, the activity of NG-700 was 18.5 times higher than that of the most popular metal-based catalyst of nanocrystalline Co3O4 in PMS activation. Theoretical calculations using spin-unrestricted density functional theory (DFT) were carried out to probe the active sites for PMS activation on N-doped graphene. In addition, experimental detection of generated radicals using electron paramagnetic resonance (EPR) and competitive radical reactions was performed to reveal the PMS activation processes and pathways of phenol degradation on nanocarbons. It was observed that both (•)OH and SO4(•-) existed in the oxidation processes and played critical roles for phenol oxidation.

HPV16L1-attenuated Shigella recombinant vaccine induced strong vaginal and systemic immune responses in guinea pig model.

Though human papillomavirus (HPV) vaccines based on L1 virus-like particles (VLPs) have excellent protective effect against HPV-induced cervical cancer, they are too expensive to be afforded by the developing countries, where most cases of cervical cancer occur. A live bacterial-based vaccine could be an inexpensive alternative. The aim of this study was to evaluate the potential value of live attenuated Shigella. flexneri 2a sc602 strain-based HPV16L1 as a high-efficiency, low-cost HPV16L1 mucosal vaccine. Recombinant sc602/L1 vaccine induced high L1-specific systemic and mucosal immune responses as well as cell-mediated Th1 and Th2 immune responses in guinea pig model. Sc602/L1 vaccine induced higher L1-specific IgG and IgA antibodies as well as HPV16-neutralizing antibodies in genital region in sc602/L1 mucosal immunized animals than in L1 intramuscular immunized animals. Though both are via mucosal delivery, immunized sc602/L1 vaccine by rectum route induced higher L1-specific IgA and IgG titers in genital region than by conjunctiva route. In addition, sc602/L1 also strongly increased L1-specific IFN-γ and IL-4 expression, implying its effect on cell-mediated immune response. HPV16L1 was expressed in sc602 bacteria and their biologic characteristics were detected by immunoblot, electron microscope and HeLa cell invasion assay. Guinea pigs were immunized with sc602L1 through conjunctiva (i.c.) or rectum (i.r.). Mucosal and systemic immune responses were detected by ELISA, ELISPOT and Neutralization activity assays. Strong mucosal and systemic immune responses were induced by sc602/L1 vaccine. This study provides evidence that sc602/L1 vaccine may have protective effect on HPV infection.

Hierarchical CO(2)-protective shell for highly efficient oxygen reduction reaction.

The widespread application of intermediate-temperature solid oxide fuel cells is mainly being hurdled by the cathode's low efficiency on oxygen reduction reaction and poor resistance to carbon dioxide impurity. Here we report the fabrication of a hierarchical shell-covered porous cathode through infiltration followed by microwave plasma treatment. The hierarchical shell consists of a dense thin-film substrate with cones on the top of the substrate, leading to a three-dimensional (3D) heterostructured electrode. The shell allows the cathode working stably in CO(2)-containing air, and significantly improving the cathode's oxygen reduction reactivity with an area specific resistance of ∼0.13 Ωcm(2) at 575°C. The method is also suitable for fabricating functional shell on the irregularly shaped substrate in various applications.

Heterostructured electrode with concentration gradient shell for highly efficient oxygen reduction at low temperature.

Heterostructures of oxides have been widely investigated in optical, catalytic and electrochemical applications, because the heterostructured interfaces exhibit pronouncedly different transport, charge, and reactivity characteristics compared to the bulk of the oxides. Here we fabricated a three-dimensional (3D) heterostructured electrode with a concentration gradient shell. The concentration gradient shell with the composition of Ba(0.5-x)Sr(0.5-y)Co(0.8)Fe(0.2)O(3-δ) (BSCF-D) was prepared by simply treating porous Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) (BSCF) backbone with microwave-plasma. Electrochemical impedance spectroscopy reveals that the oxygen surface exchange rate of the BSCF-D is enhanced by ~250% that of the pristine BSCF due to the appearance of the shell. The heterostructured electrode shows an interfacial resistance as low as 0.148 Ω cm(2) at 550°C and an unchanged electrochemical performance after heating treatment for 200 h. This method offers potential to prepare heterostructured oxides not only for electrochemical devices but also for many other applications that use ceramic materials.