Synthesis and Application of Copper Nanowires and Silver Nanosheet-Coated Copper Nanowires as Nanofillers in Several Polymers

A large amount of copper (Cu) nanowires was synthesized through the reduction of Cu(OH)2 by hydrazine in an aqueous solution containing NaOH and ethylenediamine. Besides, Cu nanowires coated by silver nanosheet (denoted as Cu@Ag nanowires) were prepared with a facile transmetalation reaction method. In the meantime, the as‐prepared Cu and Cu@Ag nanowires were used as the nanofillers of polyvinyl chloride (PVC), ultra‐high molecular weight polyethylene (UHMWPE) and epoxy resin (EP), and their effects on the thermal properties and mechanical properties as well as friction and wear behavior of the polymer‐matrix composites nanocomposites were examined. Results indicate that the as‐prepared Cu@Ag nanowires consist of Cu nanowires core and Ag nanosheet shell. The Ag nanosheet shell can well inhibit the oxidation of the Cu nanowires core, thereby providing the as‐prepared Cu@Ag nanowires with good thermal stability even at an elevated temperature of 230°C. As compared with Cu nanowires, Cu@Ag nanowires could effectively increase the thermal stability of the PVC matrix composites. Moreover, due to the special morphology and microstructure, the as‐prepared Cu@Ag nanowires can effectively improve the mechanical properties and wear resistance of PVC, UHMWPE, and EP

3,3′-[Biphenyl-4,4′-diylbis(­oxy)]diphthalic acid

In the title mol­ecule, C28H18O10, the two central benzene rings form a dihedral angle of 31.0 (1)°. In the phthalic acid fragments, the carb­oxy groups in the meta positions are approximately coplanar with the attached benzene rings, being inclined to their planes at 2.7 (1) and 10.3 (1)°, while the carb­oxy groups in the ortho positions are twisted from the benzene ring planes by 83.5 (1) and 75.4 (1)°. In the crystal, O—H⋯O hydrogen bonds link the mol­ecules into layers parallel to the bc plane. Weak C—H⋯O hydrogen bonds and π–π inter­actions between the aromatic rings [centroid–centroid distance = 3.7674 (3) Å] further consolidate the crystal packing

Largely tunable band structures of few-layer InSe by uniaxial strain

Due to the strong quantum confinement effect, few-layer {\gamma}-InSe exhibits a layer-dependent bandgap, spanning the visible and near infrared regions, and thus recently draws tremendous attention. As a two-dimensional material, the mechanical flexibility provides an additional tuning knob for the electronic structure. Here, for the first time, we engineer the band structures of few-layer and bulk-like InSe by uniaxial tensile strain, and observe salient shift of photoluminescence (PL) peaks. The shift rate of the optical gap is approximately 90-100 meV per 1% strain for 4- to 8-layer samples, which is much larger than that for the widely studied MoS2 monolayer. Density functional calculations well reproduce the observed layer-dependent bandgaps and the strain effect, and reveal that the shift rate decreases with increasing layer number for few-layer InSe. Our study demonstrates that InSe is a very versatile 2D electronic and optoelectronic material, which is suitable for tunable light emitters, photo-detectors and other optoelectronic devices.Comment: submitte

Optical Limiting and Theoretical Modelling of Layered Transition Metal Dichalcogenide Nanosheets

Nonlinear optical property of transition metal dichalcogenide (TMDC) nanosheet dispersions, including MoS2, MoSe2, WS2, and WSe2, was performed by using Z-scan technique with ns pulsed laser at 1064 nm and 532 nm. The results demonstrate that the TMDC dispersions exhibit significant optical limiting response at 1064 nm due to nonlinear scattering, in contrast to the combined effect of both saturable absorption and nonlinear scattering at 532 nm. Selenium compounds show better optical limiting performance than that of the sulfides in the near infrared. A liquid dispersion system based theoretical modelling is proposed to estimate the number density of the nanosheet dispersions, the relationship between incident laser fluence and the size of the laser generated micro-bubbles, and hence the Mie scattering-induced broadband optical limiting behavior in the TMDC dispersions

Functional near-infrared spectroscopy as a potential objective evaluation technique in neurocognitive disorders after traumatic brain injury

Most patients with neurocognitive disorders after traumatic brain injury (TBI) show executive dysfunction, in which the pre-frontal cortex (PFC) plays an important role. However, less objective evaluation technique could be used to assess the executive dysfunction in these patients. Functional near-infrared spectroscopy (fNIRS), which is a non-invasive technique, has been widely used in the study of psychiatric disorders, cognitive dysfunction, etc. The present study aimed to explore whether fNIRS could be a technique to assess the damage degree of executive function in patients with neurocognitive disorders after TBI by using the Stroop and N-back tasks in PFC areas. We enrolled 37 patients with neurocognitive disorders after TBI and 60 healthy controls. A 22-channel fNIRS device was used to record HbO during Stroop, 1-back and 2-back tasks. The results showed that patients made significantly more errors and had longer response times than healthy controls. There were statistically significant differences in HbO level variation in bilateral frontopolar, bilateral inferior frontal gyrus and left middle temporal gyrus during Stroop color word consistency tasks and in left frontopolar during Stroop color word inconsistency tasks. During 2-back tasks, there were also statistically significant differences in HbO level variation in bilateral frontopolar, bilateral inferior frontal gyrus, bilateral dorsolateral pre-frontal cortex. According to brain activation maps, the patients exhibited lower but more widespread activation during the 2-back and Stroop color word consistency tasks. The fNIRS could identify executive dysfunction in patients with neurocognitive disorders after TBI by detecting HbO levels, which suggested that fNIRS could be a potential objective evaluation technique in neurocognitive disorders after TBI

Measurement and correlation of liquid - Liquid equilibria of three imidazolium ionic liquids with acetone and cyclohexane

Ionic liquids (ILs) can be recycled as extractants for their low vapor pressure and volatility. More and more applications are applied to the separation of industrial organic matter. The industrial production of ILs has gradually been realized, which also widens the way for the application of ILs. In this work, the liquid-liquid extraction of cyclohexane-acetone azeotropic mixture with different ILs {1-butyl-3-methylimidazolium bis(trifluormethylsulfonyl), 1-butyl-3-methylimidazolium trifluoromethansulfonate and 1-butyl-3-methylimidazolium dicyanamide} is studied. The extraction mechanism is discussed based on the molecular scale. The relationship between hydrogen bond donor and acceptor between ILs and acetone is analyzed by COSMO-SAC. The interaction between molecules is optimized and calculated by Materials Studio 7.0. The extraction ability of ILs is analyzed by radial distribution function, and the experimental results are verified. The liquid-liquid equilibrium test is carried out at 298.15 K. Distribution and selectivity are indices used to judge the extraction efficiency of ILs. The NRTL model and UNIQUAC model are adopted to correlate the liquid-liquid equilibrium data. The results show that all of the two models can well correlate the experimental.This work is supported by the National Natural Science Foundation of China (No. 21776145), National Natural Science Foundation of China (No. 21676152)

Does Serum Vitamin D Level Affect COVID-19 Infection and Its Severity?-A Case-Control Study

Background: As effective medication to treat COVID-19 is currently unavailable, preventive remedies may be particularly important. Objective: To examine the relationship between serum 25-hydroxy vitamin D (25(OH)D) level and COVID-19 infection, its severity, and its clinical case characteristics. Methods: This case-control study compared serum 25(OH)D levels and rates of vitamin D deficiency (VDD) between 80 healthy controls and 62 patients diagnosed with COVID-19 and admitted to Guangxi People’s Hospital, China, 2/16/2020–3/16/2020. Cases were categorized into asymptomatic, mild/moderate, and severe/critical disease. Logistic regression analysis was conducted to examine the associations between 25(OH)D level, or VDD, and case status/severity of COVID-19 while controlling for demographics and comorbidities. A threshold level of vitamin D for conveying COVID-19 risk was estimated. Results: Severe/critical COVID-19 cases were significantly older and had higher percentages of comorbidity (renal failure) compared to mild cases. The serum 25(OH)D concentration in COVID-19 patient was much lower than that in healthy control. And 25(OH)D level was the lowest in severe/ critical cases, compared with mild cases. In further, significantly higher rates of VDD were found in COVID-19 cases (41.9%) compared to healthy controls (11.1%). And VDD was the greatest in severe/critical cases (80%), compared with mild cases (36%). These statistically significant associations remained even after controlling for demographics and comorbidities. A potential threshold of 25(OH)D (41.19nmol/L) to protect against COVID-19 was identified. Conclusion: Elderly and people with comorbidities were susceptible to severe COVID-19 infection. VDD was a risk factor for COVID-19, especially for severe/critical cases. While further confirmation is needed, vitamin D supplementation may have prevention or treatment potential for COVID- 19 disease

PERK-Mediated Cholesterol Excretion from IDH Mutant Glioma Determines Anti-Tumoral Polarization of Microglia

Isocitrate dehydrogenase (IDH) mutation, a known pathologic classifier, initiates metabolic reprogramming in glioma cells and has been linked to the reaction status of glioma-associated microglia/macrophages (GAMs). However, it remains unclear how IDH genotypes contribute to GAM phenotypes. Here, it is demonstrated that gliomas expressing mutant IDH determine M1-like polarization of GAMs, while archetypal IDH induces M2-like polarization. Intriguingly, IDH-mutant gliomas secrete excess cholesterol, resulting in cholesterol-rich, pro-inflammatory GAMs without altering their cholesterol biosynthesis, and simultaneously exhibiting low levels of tumoral cholesterol due to expression remodeling of cholesterol transport molecules, particularly upregulation of ABCA1 and downregulation of LDLR. Mechanistically, a miR-19a/LDLR axis-mediated novel post-transcriptional regulation of cholesterol uptake is identified, modulated by IDH mutation, and influencing tumor cell proliferation and invasion. IDH mutation-induced PERK activation enhances cholesterol export from glioma cells via the miR-19a/LDLR axis and ABCA1/APOE upregulation. Further, a synthetic PERK activator, CCT020312 is introduced, which markedly stimulates cholesterol efflux from IDH wild-type glioma cells, induces M1-like polarization of GAMs, and consequently suppresses glioma cell invasion. The findings reveal an essential role of the PERK/miR-19a/LDLR signaling pathway in orchestrating gliomal cholesterol transport and the subsequent phenotypes of GAMs, thereby highlighting a novel potential target pathway for glioma therapy

Expression profiling of ALOG family genes during inflorescence development and abiotic stress responses in rice (Oryza sativa L.)

The ALOG (Arabidopsis LSH1 and Oryza G1) family proteins, namely, DUF640 domain-containing proteins, have been reported to function as transcription factors in various plants. However, the understanding of the response and function of ALOG family genes during reproductive development and under abiotic stress is still largely limited. In this study, we comprehensively analyzed the structural characteristics of ALOG family proteins and their expression profiles during inflorescence development and under abiotic stress in rice. The results showed that OsG1/OsG1L1/2/3/4/5/6/7/8/9 all had four conserved helical structures and an inserted Zinc-Ribbon (ZnR), the other four proteins OsG1L10/11/12/13 lacked complete Helix-1 and Helix-2. In the ALOG gene promoters, there were abundant cis-acting elements, including ABA, MeJA, and drought-responsive elements. Most ALOG genes show a decrease in expression levels within 24 h under ABA and drought treatments, while OsG1L2 expression levels show an upregulated trend under ABA and drought treatments. The expression analysis at different stages of inflorescence development indicated that OsG1L1/2/3/8/11 were mainly expressed in the P1 stage; in the P4 stage, OsG1/OsG1L4/5/9/12 had a higher expression level. These results lay a good foundation for further studying the expression of rice ALOG family genes under abiotic stresses, and provide important experimental support for their functional research

Synthesis of Monodisperse Nanocrystals via Microreaction: Open-to-Air Synthesis with Oleylamine as a Coligand

Microreaction provides a controllable tool to synthesize CdSe nanocrystals (NCs) in an accelerated fashion. However, the surface traps created during the fast growth usually result in low photoluminescence (PL) efficiency for the formed products. Herein, the reproducible synthesis of highly luminescent CdSe NCs directly in open air was reported, with a microreactor as the controllable reaction tool. Spectra investigation elucidated that applying OLA both in Se and Cd stock solutions could advantageously promote the diffusion between the two precursors, resulting in narrow full-width-at-half maximum (FWHM) of PL (26 nm). Meanwhile, the addition of OLA in the source solution was demonstrated helpful to improve the reactivity of Cd monomer. In this case, the focus of size distribution was accomplished during the early reaction stage. Furthermore, if the volume percentage (vol.%) of OLA in the precursors exceeded a threshold of 37.5%, the resulted CdSe NCs demonstrated long-term fixing of size distribution up to 300 s. The observed phenomena facilitated the preparation of a size series of monodisperse CdSe NCs merely by the variation of residence time. With the volume percentage of OLA as 37.5% in the source solution, a 78 nm tuning of PL spectra (from 507 to 585) was obtained through the variation of residence time from 2 s to 160 s, while maintaining narrow FMWH of PL (26–31 nm) and high QY of PL (35–55%)