Altered functional connectivity between primary motor cortex subregions and the whole brain in patients with incomplete cervical spinal cord injury

To investigate the reorganizations of gray matter volume (GMV) in each subregion of primary motor cortex (M1) after incomplete cervical cord injury (ICCI) and to explore the differences in functional connectivity (FC) between the M1 subregions and the whole brain, and further to disclose the potential value of each M1 subregion in motor function rehabilitation of ICCI patients. Eighteen ICCI patients and eighteen age- and gender- matched healthy controls (HCs) were recruited in this study. The 3D high-resolution T1-weighted structural images and resting-state functional magnetic resonance imaging (rs-fMRI) of all subjects were obtained using a 3.0 Tesla MRI system. Based on the Human Brainnetome Atlas, the structural and functional changes of M1 subregions (including A4hf, A6cdl, A4ul, A4t, A4tl, A6cvl) in ICCI patients were analyzed by voxel-based morphometry (VBM) and seed-based FC, respectively. Compared with HCs, no structural changes in the M1 subregions of ICCI patients was detected. However, when compared with HCs, ICCI patients exhibited decreased FC in visual related areas (lingual gyrus, fusiform gyrus) and sensorimotor related areas (primary sensorimotor cortex) when the seeds were located in bilateral A4hf, A4ul, and decreased FC in visual related areas (lingual gyrus, fusiform gyrus) and cognitive related areas (temporal pole) when the seed was located in the left A4t. Moreover, when the seeds were located in the bilateral A6cdl, decreased FC in visual related areas (lingual gyrus, fusiform gyrus, calcarine gyrus) was also observed. Our findings demonstrated that each of the M1 regions had diverse FC reorganizations, which may provide a theoretical basis for the selection of precise stimulation targets, such as transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tCDS), meanwhile, our results may reveal the possible mechanism of visual feedback and cognitive training to promote motor rehabilitation.

Atomically Dispersed Platinum Modulated by Sulfide as an Efficient Electrocatalyst for Hydrogen Evolution Reaction

Catalytically active metals atomically dispersed on supports presents the ultimate atom utilization efficiency and cost-effective pathway for electrocatalyst design. Optimizing the coordination nature of metal atoms represents the advanced strategy for enhancing the catalytic activity and the selectivity of single-atom catalysts (SACs). Here, we designed a transition-metal based sulfide-Ni3S2 with abundant exposed Ni vacancies created by the interaction between chloride ions and the functional groups on the surface of Ni3S2 for the anchoring of atomically dispersed Pt (PtSA-Ni3S2). The theoretical calculation reveals that unique Pt-Ni3S2 support interaction increases the d orbital electron occupation at the Fermi level and leads to a shift-down of the d -band center, which energetically enhances H2O adsorption and provides the optimum H binding sites. Introducing Pt into Ni position in Ni3S2 system can efficiently enhance electronic field distribution and construct a metallic-state feature on the Pt sites by the orbital hybridization between S-3p and Pt-5d for improved reaction kinetics. Finally, the fabricated PtSA-Ni3S2 SAC is supported by Ag nanowires network to construct a seamless conductive three-dimensional (3D) nanostructure (PtSA-Ni3S2@Ag NWs), and the developed catalyst shows an extremely great mass activity of 7.6 A mg-1 with 27-time higher than the commercial Pt/C HER catalyst.

Optical Fiber Delivered Ultrafast Plasmonic Optical Switch

Ultrafast optical switch based on plasmonic nanostructures has large application potentials in optical logic circuits and optical communication systems. Integration of plasmonic optical switching devices with optical fibers is a breakthrough for realizing practical applications in long-range optical data transmission or communication techniques. Here, the incorporation of plasmonic optical switch devices onto the end facets of optical fibers is reported, so that the switched optical signals are generated by interaction between femtosecond laser pulses and plasmonic nanostructures on one end of the fiber, and are delivered via the fiber waveguide to the other end for detection or decoding. "Quenching" of localized surface plasmon in the gold nanowires by its interaction with band-edge modulation in gold through strong optical excitation is the responsible photophysics. This work accomplishes for the first time the implementation of ultrafast plasmonic optical switch device on optical fiber tips for logic data transmission.

A Theoretical Study on Terpene-Based Natural Deep Eutectic Solvent: Relationship between Viscosity and Hydrogen-Bonding Interactions

The aim of this work is to shed light on the origins of unique properties by studying the relationship between viscosity and hydrogen-bonding interactions of terpene-based natural deep eutectic solvents (NADES). Five systems including camphor/formic acid, menthol/acetic acid, menthol/β-citronellol, menthol/lactic acid, and thymol/β-citronellol are prepared (molar ratio 1:1). Their structures and nature of the associated hydrogen bonds are investigated through multiple methods and theories. The viscosity of NADES is consistent with the product of hydrogen-bond number and lifetime. Through visualization of non-covalent interactions, terpene-acid-based NADES with single sites show the lowest viscosity among the studied systems because of weak and unstable hydrogen bonding. Inversely, multi-site terpene-acid-based NADES possess relatively high viscosity. Owing to the stability of hydrogen bonds in the network, the terpene-terpene-based system is in the middle level of viscosity. In-depth analysis of these hydrogen bonds shows that they can be classified as "weak to medium" and are mainly derived from electrostatic interactions. Moreover, there is an obvious connection between viscosity and hydrogen-bonding strength (integrated core-valence bifurcation index) in the networks. The discovery of intrinsic rules between viscosity and hydrogen-bonding interactions is beneficial for the design of novel low-viscosity NADES in the future.

COVID-19 diagnostic testing: Technology perspective

The corona virus disease 2019 (COVID-19) is a highly contagious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). More than 18 million people were infected with a total of 0.7 million deaths in ∼188 countries. Controlling the spread of SARS-CoV-2 is therefore inherently dependent on identifying and isolating infected individuals, especially since COVID-19 can result in little to no symptoms. Here, we provide a comprehensive review of the different primary technologies used to test for COVID-19 infection, discuss the advantages and disadvantages of each technology, and highlight the studies that have employed them. We also describe technologies that have the potential to accelerate SARS-CoV-2 detection in the future, including digital PCR, CRISPR, and microarray. Finally, remaining challenges in COVID-19 diagnostic testing are discussed, including (a) the lack of universal standards for diagnostic testing; (b) the identification of appropriate sample collection site(s); (c) the difficulty in performing large population screening; and (d) the limited understanding of SARS-COV-2 viral invasion, replication, and transmission.

Hydrophobic Metal-Organic Frameworks: Assessment, Construction, and Diverse Applications

Tens of thousands of metal-organic frameworks (MOFs) have been developed in the past two decades, and only ≈100 of them have been demonstrated as porous and hydrophobic. These hydrophobic MOFs feature not only a rich structural variety, highly crystalline frameworks, and uniform micropores, but also a low affinity toward water and superior hydrolytic stability, which make them promising adsorbents for diverse applications, including humid CO2 capture, alcohol/water separation, pollutant removal from air or water, substrate-selective catalysis, energy storage, anticorrosion, and self-cleaning. Herein, the recent research advancements in hydrophobic MOFs are presented. The existing techniques for qualitatively or quantitatively assessing the hydrophobicity of MOFs are first introduced. The reported experimental methods for the preparation of hydrophobic MOFs are then categorized. The concept that hydrophobic MOFs normally synthesized from predesigned organic ligands can also be prepared by the postsynthetic modification of the internal pore surface and/or external crystal surface of hydrophilic or less hydrophobic MOFs is highlighted. Finally, an overview of the recent studies on hydrophobic MOFs for various applications is provided and suggests the high versatility of this unique class of materials for practical use as either adsorbents or nanomaterials.