3,955 research outputs found

    Investigation of the shape transferability of nanoscale multi-tip diamond tools in the diamond turning of nanostructures

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    In this article, the shape transferability of using nanoscale multi-tip diamond tools in the diamond turning for scale-up manufacturing of nanostructures has been demonstrated. Atomistic multi-tip diamond tool models were built with different tool geometries in terms of the difference in the tip cross-sectional shape, tip angle, and the feature of tool tip configuration, to determine their effect on the applied forces and the machined nano-groove geometries. The quality of machined nanostructures was characterized by the thickness of the deformed layers and the dimensional accuracy achieved. Simulation results show that diamond turning using nanoscale multi-tip tools offers tremendous shape transferability in machining nanostructures. Both periodic and non-periodic nano-grooves with different cross-sectional shapes can be successfully fabricated using the multi-tip tools. A hypothesis of minimum designed ratio of tool tip distance to tip base width (L/Wf) of the nanoscale multi-tip diamond tool for the high precision machining of nanostructures was proposed based on the analytical study of the quality of the nanostructures fabricated using different types of the multi-tip tools. Nanometric cutting trials using nanoscale multi-tip diamond tools (different in L/Wf) fabricated by focused ion beam (FIB) were then conducted to verify the hypothesis. The investigations done in this work imply the potential of using the nanoscale multi-tip diamond tool for the deterministic fabrication of period and non-periodic nanostructures, which opens up the feasibility of using the process as a versatile manufacturing technique in nanotechnology

    Can lignocellulosic hydrocarbon liquids rival lignocellulose-derived ethanol as a future transport fuel?

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    Although transport fuels are currently obtained mainly from petroleum, alternative fuels derived from lignocellulosic biomass (LB) have drawn much attention in recent years in light of the limited reserves of crude oil and the associated environmental issues. Lignocellulosic ethanol (LE) and lignocellulosic hydrocarbons (LH) are two typical representatives of the LB-derived transport fuels. This editorial systematically compares LE and LB from production to their application in transport fuels. It can be demonstrated that LH has many advantages over LE relative to such uses. However, most recent studies on the production of the LB-derived transport fuels have focused on LE production. Hence, it is strongly recommended that more research should be aimed at developing an efficient and economically viable process for industrial LH production

    A cucurbit[8]uril-based fluorescent probe for the selective detection of pymetrozine

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    Herein, we report a simple fluorescence-enhanced system for the selective recognition and determination of the insecticide pymetrozine. 1H NMR spectroscopic data indicate that 1,2-bis(4-pyridyl)ethylene (BPE) is partially encapsulated in the cavity of the cucurbit[8]uril (Q[8]) in aqueous solution, forming a stable 1:2 host-guest inclusion complex. Good evidence is also provided by other characterization techniques including single crystal X-ray diffraction, UV-Vis and fluorescence spectroscopies. This host-guest inclusion complex shows weak fluorescence in aqueous solution. Interestingly, the addition of pymetrozine greatly enhanced the fluorescence of the host-guest inclusion complex. In contrast, no significant fluorescence enhancement was observed on addition of 10 other pesticides. The concentration of pymetrozine in aqueous solution was easily detected based on the linear relationship between fluorescence intensity and pymetrozine concentration. Therefore, this paper reports a new method to identify and determine pymetrozine by fluorescence enhancement

    Research progress on the immune microenvironment and immunotherapy in gastric cancer

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    The tumor microenvironment, particularly the immune microenvironment, plays an indispensable role in the malignant progression and metastasis of gastric cancer (GC). As our understanding of the GC microenvironment continues to evolve, we are gaining deeper insights into the biological mechanisms at the single-cell level. This, in turn, has offered fresh perspectives on GC therapy. Encouragingly, there are various monotherapy and combination therapies in use, such as immune checkpoint inhibitors, adoptive cell transfer therapy, chimeric antigen receptor T cell therapy, antibody-drug conjugates, and cancer vaccines. In this paper, we review the current research progress regarding the GC microenvironment and summarize promising immunotherapy research and targeted therapies

    Selective detection of paraquat by a cucurbit[7]uril-based fluorescent probe

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    A simple fluorescent “on-off” system that can be utilized for the selective identification and determination of paraquat (PQ) is presented herein. 1H NMR spectroscopic data indicated that in aqueous solution the alkaloid palmatine can be partially encapsulated within the cucurbit[7]uril (Q[7]) cavity, whereby a stable 1: 1 host–guest inclusion complex is formed. Other characterization techniques including mass spectrometry, UV-Vis and fluorescence spectroscopy also provided further evidence, and the host-guest inclusion complex was found to exhibit reasonable fluorescence intensity. It is noteworthy that the addition of PQ resulted in quenching the fluorescence of the host-guest inclusion complex, whereas the presence of 12 other pesticides did not significantly affect the fluorescence intensity. Given the linear relationship between the intensity of the fluorescence and the PQ concentration, the PQ concentration in aqueous solution was easily detected. Thus, a new method for identifying and determining the fluorescence quenching of PQ has been developed in this work

    Sodium‐Doped Tin Sulfide Single Crystal: A Nontoxic Earth‐Abundant Material with High Thermoelectric Performance

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    Lead‐free tin sulfide (SnS), with an analogous structure to SnSe, has attracted increasing attention because of its theoretically predicted high thermoelectric performance. In practice, however, polycrystalline SnS performs rather poorly as a result of its low power factor. In this work, bulk sodium (Na)‐doped SnS single crystals are synthesized using a modified Bridgman method and a detailed transport evaluation is conducted. The highest zT value of ≈1.1 is reached at 870 K in a 2 at% Na‐doped SnS single crystal along the b‐axis direction, in which high power factors (2.0 mW m−1 K−2 at room temperature) are realized. These high power factors are attributed to the high mobility associated with the single crystalline nature of the samples as well as to the enhanced carrier concentration achieved through Na doping. An effective single parabolic band model coupled with first‐principles calculations is used to provide theoretical insight into the electronic transport properties. This work demonstrates that SnS‐based single crystals composed of earth‐abundant, low‐cost, and nontoxic chemical elements can exhibit high thermoelectric performance and thus hold potential for application in the area of waste heat recovery.Large size Sn1−xNaxS single crystals were firstly obtained using a modified Bridgman method. The multiple band feature along with the single crystalline nature favors a large power factor, leading to the highest dimensionless figure of merit (zT) of ~1.1 at 870 K for 2 at% Na‐doped SnS single crystal along the b‐axis, which is one of the best results for thermoelectric sulfides to date.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145294/1/aenm201800087_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145294/2/aenm201800087-sup-0001-S1.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145294/3/aenm201800087.pd

    Liraglutide Ameliorates β-Amyloid Deposits and Secondary Damage in the Ipsilateral Thalamus and Sensory Deficits After Focal Cerebral Infarction in Rats

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    Focal cerebral infarction causes β-amyloid (Aβ) deposition and secondary neuronal degeneration in the ipsilateral thalamus. Thalamus is the subcortical center of sensory, the damage of thalamus could cause sensory deficits. The present study aimed to investigate the protective effects of liraglutide, a long-acting glucagon-like peptide-1 (GLP)-1 receptor agonist, on Aβ deposits and secondary damage in the ipsilateral thalamus after focal cerebral infarction. In addition, this study was conducted to investigate whether liraglutide could improve sensory function after focal cerebral infarction. Forty-two male Sprague–Dawley rats were subjected to distal middle cerebral artery occlusion (MCAO) and then randomly divided into liraglutide and vehicle groups, and 14 sham-operated rats as control. At 1 h after MCAO, rats in the liraglutide and vehicle groups were subcutaneously injected with liraglutide (100 μg/kg/d) and isopyknic vehicle, respectively, once a day for 7 days. Sensory function and secondary thalamic damage were assessed using adhesive-removal test and Nissl staining and immunostaining, respectively, at 7 days after MCAO. Terminal deoxynucleotidyl transferase 2’-deoxyuridine 5’-triphosphate nick end labeling and Western blot were used to detect neuronal apoptosis. The results showed that liraglutide improved sensory deficit compared to the controls. Liraglutide treatment significantly reduced Aβ deposition compared with the vehicle treatment. Liraglutide treatment decreased the neuronal loss, astroglial and microglial activation, and apoptosis compared with the vehicle treatment. Liraglutide significantly down-regulated the expression of Bcl-2 and up-regulated that of Bax in the ipsilateral thalamus compared with the vehicle group. These results suggest that liraglutide ameliorates the deposition of Aβ and secondary damage in the ipsilateral thalamus, potentially contributing to improve sensory deficit after focal cerebral infarction
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