SAMHD1 dysfunction induces IL-34 expression via NF-κB p65 in neuronal SH-SY5Y cells.

Dysfunctional mutations in SAMHD1 cause Aicardi-Goutières Syndrome, an autoinflammatory encephalopathy with elevated interferon-α levels in the cerebrospinal fluid. Whether loss of function mutations in SAMHD1 trigger the expression of other cytokines apart from type I interferons in Aicardi-Goutières Syndrome is largely unclear. This study aimed to explore whether SAMHD1 dysfunction regulated the expression of IL-34, a key cytokine controlling the development and maintenance of microglia, in SH-SY5Y neural cells. We found that downregulation of SAMHD1 in SH-SY5Y cells resulted in the upregulation of IL-34 expression. The protein and mRNA levels of NF-κB p65, the transactivating subunit of a transcription factor NF-κB, were also upregulated in SAMHD1-knockdown SH-SY5Y cells. It was further found SAMHD1 knockdown in SH-SY5Y cells induced an upregulation of IL-34 expression through the canonical NF-κB-dependent pathway in which NF-κB p65, IKKα/ß and the NF-κB inhibitor IκBα were phosphorylated. Moreover, knockdown of SAMHD1 in SH-SY5Y cells led to the translocation of NF-κB p65 into the nucleus and promoted NF-κB transcriptional activity. In conclusion, we found SAMHD1 dysfunction induced IL-34 expression via NF-κB p65 in neuronal SH-SY5Y cells. This finding could lay the foundation for exploring the role of IL-34-targeting microglia in the pathogenesis of Aicardi-Goutières Syndrome.

Unexpected reduction in thermal conductivity observed in graphene/h-BN heterostructures.

Heterostructures find wide-ranging applications in fields such as thermal management, thermoelectric energy conversion, and nanoelectronics. This study provides new insights into the thermal conductivity of parallel heterointerfaces by investigating a longitudinal heterostructure composed of graphene and hexagonal boron nitride (h-BN) using molecular dynamics simulations. Interestingly, it is observed that this unique heterostructure possesses a lower thermal conductivity compared to pure h-BN. The analysis reveals that phonon scattering is enhanced by stress at the interface of the heterostructure and the mass distribution through it. The heterostructure model introduced in this study presents new insights for controlling phonon transportation in nanoscale structures.

The observation of the curative effect of silver-containing dressings combined with hydrogel on healing of immunosuppression-induced skin ulcerations.

BACKGROUND: Local inflammatory reaction is the basis of wound healing. Inappropriate inflammatory reaction will delay wound healing. OBJECTIVE: This study aimed to investigate the effect of silver-containing dressings combined with hydrogel on healing of immunosuppression-induced skin ulcerations (IISU). METHODS: A retrospective analysis was conducted on 48 cases of patients with IISU admitted to The First People's Hospital of Jiande from March 2018 to March 2019. According to the different treatment methods, the patients were divided into the observation group and the control group, with 24 cases in each group. Patients in the observation group were treated with silver-containing dressings combined with hydrogel, while patients in the control group were treated with silver-containing dressings alone. Initially, patients in the observation group and control group were treated with the same method of debridement and cleaning. Afterwards, for patients in the observation group, the wounded surface was coated with a layer of hydrogel. Both groups had the wound covered with a silver-containing dressing as the inner dressing, and gauze was used as the outer dressing to wrap and fix the wound. The dressing change frequency was the same for both groups. The effective rate, basic healing rate, and complete healing rate of the two groups were compared after one week and two weeks of treatment. RESULTS: The effective rate of dressing application and wound healing rate in the observation group were significantly better than those in the control group, and the differences were statistically significant (P< 0.05). CONCLUSION: A silver-containing dressing combined with hydrogel as the inner dressing can provide a better environment for wound healing, significantly shorten the course of treatment of patients with IISU, promote the early recovery of patients, and improve the quality of life of patients. Therefore, it can be applied in clinical practice.

Ultrahigh-Loaded Fe Single Atoms and Fe3C Nanoparticle Catalysts as Air Cathodes for High-Performance Zn-Air Batteries.

Fe-based materials containing Fe-Nx sites have emerged as promising electrocatalysts in the oxygen reduction reaction (ORR), but they still suffer structural instability which may lead to loss of catalytic activity. Herein, a novel electrocatalyst Fe3C-FeSA@3DCN with the coexistence of Fe3C nanoparticles and Fe single atoms (FeSA) in a three-dimensional conductive network (3DCN) is prepared via lattice confinement and defect trapping strategies with an Fe atomic loading of as high as 4.36%. In the ORR process, the limiting current density of Fe3C-FeSA@3DCN reaches 5.72 mA cm-2, with an onset potential of 0.926 V and a Tafel slope of 66 mV/decade, showing better catalytic activity and stability than Pt/C catalysts. Notably, its assembled aqueous and solid-state Zn-air batteries (ZABs) achieve peak power densities of 166 and 56 mW cm-2, respectively, with a long service life of up to 200 h at a current density of 5 mA cm-2. In addition, the assembled ZAB can provide a constant voltage on activated carbon electrodes to perform capacitive deionization to adsorb different ions. The importance of the Fe species active sites generated by Fe3C and FeSA in the material for ORR activity to boost the electron transfer and mass transfer is demonstrated by a simple selective poisoning experiment.

ZIF-8-derived N-doped porous carbon wrapped in porous carbon films as an air cathode for flexible solid-state Zn-air batteries.

Metal-organic frameworks are a new type of catalyst precursor with high specific surface area and controllable composition, which can be modified by post-treatment and are suitable for use as cathode catalysts for Zn-air batteries (ZABs). Here, a self-doped nitrogen nanocatalyst (N-PC@CF) with a double-layered porous structure is rationally designed for flexible solid-state ZABs. The outer porous carbon shell of the N-PC@CF is highly hydrophilic and O2 permeable, while the layered porous structure exposes sufficient active sites to shorten the mass transfer distance, which would promote electrocatalytic performance and increase flexibility efficiently. The obtained N-PC@CF has an onset potential of 0.926 V and a half-wave potential of 0.843 V in the oxygen reduction reaction test, which is equivalent to commercial Pt/C. Most importantly, the maximum power density of the assembled ZAB is 134.7 mW cm-2 and it exhibits a specific capacity of 776.8 mA h g-1 at 10 mA cm-2, which is better than the 99.9 mW cm-2 of the Pt/C-based battery. An obvious improvement in the constant current discharge-charge cycle durability of the ZAB is found when compared with Pt/C. The specific capacities of ZAB with N-PC@CF as the air cathode at 5, 10 and 15 mA cm-2 are 842.7, 776.8 and 715.0 mAh g-1 (calculated by the mass of zinc consumed), respectively, corresponding to high energy densities of 1089.7, 977.3 and 842.2 Wh kg-1. A flexible solid-state battery is assembled with excellent flexibility and stability, even if the battery is folded into a large angle (160°). This work provides a new strategy for the design and synthesis of metal-free air cathodes.

Enhanced capacitive deionization of a low-concentration brackish water with protonated carbon nitride-decorated graphene oxide electrode.

Freshwater resources are one of the core elements that affect the harmonious development of mankind and society. Capacitive deionization (CDI) technology is one of the effective methods to transform brackish water into fresh water. The choice of material for a CDI electrode is critical to its electrosorption performance, which directly affects the electrosorption performance through interface optimization. Herein, protonated carbon nitride (H-C3N4)-modified graphene oxide (H-C3N4-mGO1/8) is fabricated by a simultaneous nucleophilic addition and amide reaction in order to enhance capacitive deionization of a very low concentration brackish water. Using activated carbon (AC) as the positive electrode and H-C3N4-mGO1/8 as the negative electrode, H-C3N4-mGO1/8 || AC asymmetric CDI devices are used to remove ions from a NaCl aqueous solution. The CDI test results indicate that the system has a high electrosorption capacity of 8.36 mg g-1 in the 50 mg L-1 NaCl solution with a low applied voltage of 1.2 V, which is 1.40 times than AC || AC symmetric. Moreover, the CDI device performs faster adsorption rate of 0.1879 mg (g·min)-1 and an excellent regeneration efficiency of 100%. The salt electrosorption capacity, electrosorption rate of the H-C3N4-mGO1/8 || AC asymmetric electrodes improve with increasing applied voltage due to the stronger Coulombic interaction between the electrode and charged ions with the formation of a more sufficient electric double layer principle.

Electrochemically reduced phytic acid-doped TiO2 nanotubes for the efficient electrochemical degradation of toxic pollutants.

Element-doped TiO2 nanotube arrays (TNAs) with optimized active sites provide an effective approach for significantly improving electrocatalytic performance. The challenges in such construction mainly include selection of green dopant and control of active sites. Herein, we present phytic acid as a phosphorus source for P-doped TNAs. An oxygen vacancy (Ov) and P co-doped TNAs (P-TiO2-y) was prepared as an electrochemical oxidation anode. P-TiO2-y exhibits excellent degradation activity due to the formation of Ti-O-P bonds and generation of Ov. P-doping was beneficial in improving the oxygen evolution potential of the electrode, which would be benefit for electrocatalytic degradation of pollutants. Using the P-TiO2-y anode with a current density of 10 mA/cm2 for tetracycline degradation, after a 3 h treatment, the removal rate, chemical oxygen demand and total organic carbon removal rates were 100%, 90.32% and 76.60%, respectively. The P-TiO2-y also has excellent degradation performance for phenol, hydroquinone, p-nitrophenol and metronidazole.

Segmentation and Re-encapsulation of Porous PtCu Nanoparticles by Generated Carbon Shell for Enhanced Ethylene Glycol Oxidation and Oxygen-Reduction Reaction.

Hierarchical porous carbon-encapsulated ultrasmall PtCu (UsPtCu@C) nanoparticles (NPs) were constructed based on segmentation and re-encapsulation of porous PtCu NPs by using glucose as a green biomass carbon source. The synergistic electronic effect from the bimetallic elements can enhance the catalytic activity by adjusting the surface electronic structure of Pt. Most importantly, the generated porous carbon shell provided a large contact surface area, excellent electrical conductivity, and structural stability, and the ultrasmall PtCu NPs exhibited an increased electrochemical performance compared with their PtCu matrix because of the exposure of more catalytically active centers. This synergistic relationship between the components resulted in enhanced catalytic activity and better stability of the obtained UsPtCu@C for ethylene glycol oxidation reaction and the oxygen-reduction reaction in alkaline electrolyte, which was higher than the PtCu NPs and commercial Pt/C (20 wt % Pt on Vulcan XC-72). The electrochemically active surface areas of the UsPtCu@C, PtCu NPs, and commercial Pt/C were calculated to be approximately 230.2, 32.8, and 64.0 m2/gPt, respectively; the mass activity of the UsPtCu@C for the ethylene glycol oxidation reaction was 8.5 A/mgPt, which was 14.2 and 8.5 times that of PtCu NPs and commercial Pt/C, respectively. The specific activity of UsPtCu@C was 3.7 mA/cmpt2, which was 2.1 and 2.3 times that of PtCu NPs and commercial Pt/C, respectively. The onset potential (Eon-set) of UsPtCu@C for the oxygen-reduction reaction was 0.96 V (vs reversible hydrogen electrode, RHE), which was 110 and 60 mV higher than PtCu and commercial Pt/C, respectively. The half-wave potentials (E1/2) of UsPtCu@C, PtCu, and Pt/C were 0.88, 0.56, and 0.82 V (vs RHE), respectively, which indicated that the UsPtCu@C catalyst had an excellent bifunctional electrocatalytic activity.

Flexural Wave Propagation in Mass Chain-Filled Carbon Nanotubes.

The propagation characteristics of terahertz (THz) flexural waves in mass chain-filled single-walled carbon nanotubes (MCSCs) are studied using a continuum mechanics approach and molecular dynamics (MD) simulations, where each single-walled carbon nanotube (SWCNT) is modeled as a nonlocal Timoshenko beam based on the nonlocal strain gradient theory. The effect of the surrounding elastic medium and the van der Waals (vdW) interactions between the mass chain and the SWCNT on the wave propagation is quantitatively considered in governing equations, respectively. The analytical expressions of two flexural wave branches and the bandgap between the two branches are derived. When combining our MD simulations of the carbon-atom chain-filled SWCNT, the wave within the bandgap disperses rapidly, and the mass chain has a significant influence on the phase velocity of the flexural wave. The present theoretical solution has a high accuracy in a wide frequency range up to the THz region. In particular, the surrounding elastic medium of the MCSCs remarkably affects the phase velocity for low frequencies, but not for high frequencies. The present study indicates that the wave propagation of a SWCNT could be modulated by changing the filled mass chain and the surrounding elastic medium.

PCC0208018 exerts antitumor effects by activating effector T cells.

Poor prognosis is associated with melanoma due to immunosuppression profiles, suggesting that immune alterations have an important role in the occurrence, growth, and metastasis of melanoma. Here, we found that PCC0208018, a small-molecule compound, enhanced T cell proliferation and activation to release interferon gamma (IFN-γ) and interleukin-2 (IL-2) without blocking the programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) binding and did not directly affect tumor cell viability in vitro. Furthermore, PCC0208018 increased the phosphorylation of protein kinase B (PKB/AKT) as well as extracellular regulated protein kinases (ERK) in human peripheral blood mononuclear cells (PBMCs) in vitro. The secretion of cytokines induced by PCC0208018 was significantly suppressed by the PI3K inhibitor GDC-0941. In B16-F10 melanoma-harboring mice, PCC0208018 significantly inhibited tumor growth as well as increasing CD3+, CD3+CD4+, and CD3+CD8+ T cell abundance in tumors without affecting PD-L1 expression. This study showed that PCC0208018 potentially increased PBMCs proliferation and function by activating the phosphatidylinositol 3 kinase (PI3K)/AKT and mitogen-activated protein kinase (MEK)/ERK pathways to exert antitumor effects.

Buckling behaviors of single-walled carbon nanotubes inserted with a linear carbon-atom chain.

Buckling behaviors of single-walled carbon nanotubes (SWCNTs) inserted with a linear carbon-atom chain (CAC) (the composite structures are also called carbon nanowires (CNWs)) under torsion and bending as well as compression are studied using molecular dynamics (MD) simulations, respectively. Our MD results show that the critical buckling angles (or strains) of CNWs under the three presented kinds of loading patterns can be two times those of corresponding independent SWCNTs for long CNWs, while the buckling improvement is not obvious for short ones. The main reason is that the radial van der Waals force between the CAC and the SWCNT is very small for a short CNW, while it increases with increasing length and then tends to a constant for a long CNW. The obtained MD results agree well with those from available theoretical models. These findings will be a great help towards understanding the stability and reliability of the special CNT structures, and designing flexible CNT-based devices.

Thermal vibration of a single-walled carbon nanotube predicted by semiquantum molecular dynamics.

Quantum effects should be considered in the thermal vibrations of carbon nanotubes (CNTs). To this end, molecular dynamics based on modified Langevin dynamics, which accounts for quantum statistics by introducing a quantum heat bath, is used to simulate the thermal vibration of a cantilevered single-walled CNT (SWCNT). A nonlocal elastic Timoshenko beam model with quantum effects (TBQN), which can take the effect of microstructure into consideration, has been established to explain the resulting power spectral density of the SWCNT. The root of mean squared (RMS) amplitude of the thermal vibration of the SWCNT obtained from semiquantum molecular dynamics (SQMD) is lower than that obtained from classical molecular dynamics, especially at very low temperature and high-order modes. The natural frequencies of the SWCNT obtained from the Timoshenko beam model are closer to those obtained from molecular dynamics if the nonlocal effect is taken into consideration. However, the nonlocal Timoshenko beam model with the law of energy equipartition (TBCN) can only predict the RMS amplitude of the SWCNT obtained from classical molecular dynamics without considering quantum effects. The RMS amplitude of the SWCNT obtained from SQMD and that obtained from TBQN coincide very well. These results indicate that quantum effects are important for the thermal vibration of the SWCNT in the case of high-order modes, short length and low temperature.

Thermal vibrations of single-layered graphene sheets by molecular dynamics.

Dynamics problems in the thermal vibration of single-layered graphene sheets (SLGSs) are investigated using molecular dynamics (MD) method based on the Brenner's second-generation reactive empirical bond order (REBO) potential. The in plane stiffness and Poisson ratio of SLGSs are calculated by stretching SLGSs. The effective thickness of SLGSs is obtained by MD simulations for the thermal vibration of SLGSs through the natural frequency. The natural frequencies for SLGSs of different sizes with initial stress in different temperatures are calculated through MD. The thin plate theory can predict the MD results very well in a certain range of strain. For the nonlinear relation between stress and strain when the strain is very large, the deviation between the MD results and plate theory becomes larger when the strain increases. The difference between the plate theory and the MD results becomes more and more obvious, when the size of graphene sheet is very small.