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The static (hyper)polarizabilities of the dimer and trimer with diffuse excess electrons, [Li+[calix[4]pyrrole]Li-]n, are firstly investigated by the DFT(B3LYP) method in detail. For the dimer and trimer, a Li atom inside each calix[4]pyrrole unit is ionized to form a diffuse excess electron. The results show that the dimer and trimer containing two and three excess electrons, respectively, have very large first hyperpolarizablities as 2.3 × 104 and 4.0 × 104 au, which are 30 and 40 times larger than that of the corresponding [calix[4]pyrrole]n (n = 2, 3) without Li atom. Also, β values of dimer and trimer are twice and four times as large as that of monomer containing one excess electron. Obviously, not only excess electron but also the number of excess electron plays an important role in increasing the first hyperpolarizability. Moreover, the (hyper)polarizabilities of the [Li+[calix[4]pyrrole]Li-]n polymer are investigated at ab initio level by using the elongation finite-field (elongation FF) method. All the oligomers of the [Li+[calix[4]pyrrole]Li-]n with many excess electrons exhibit very large first hyperpolarizability and large second hyperpolarizability. The present investigation shows that by introducing several and more excess electrons into the nonlinear optical (NLO) materials will be an important strategy for improving their NLO properties, which will be helpful for design of NLO materials. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [ABSTRACT FROM AUTHOR]

The structures, energetics, spectroscopies, and stabilities of the doublet [Si, C, N, O] radical are explored at the density functional theory and ab initio levels. Sixteen isomers are located, connected by 29 interconversion transition states. At the CCSD(T)/6-311+G(2df)//QCISD/6-311G(d)+ZPVE level, the lowest lying isomer is a linear SiNCO 1 (0.0 kcal/mol) mainly featuring a cumulene | · Si = N = C = O. The second and third low-lying isomers are bent OSiCN 2 (8.8) and bent OSiNC 3 (11.1), respectively. All the three low-lying isomers 1, 2, 3, and another high-lying species 5 (75.4) with a linear SiCNO structure are shown to have considerable kinetic stability and may be experimentally observable. The predicted results of isomers 1 and 2 are consistent with the previous mass spectrometry experiments. Moreover, the fourth low-lying species SiOCN 4 (23.9) with bent structure is expected to be observable in low-temperature environments. The bonding nature of the five isomers 1, 2, 3, 4, and 5 is analyzed. The calculated results are compared with those of the analogous molecules C2NO and Si2NO. Implications in interstellar space and N,O-doped SiC vaporization processes are also discussed. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 749–761, 2006 [ABSTRACT FROM AUTHOR]

The article discusses the development of an inhaled delivery system, iSEND, using nanovesicles loaded with dexamethasone (DEX) to attenuate the cytokine storm in COVID-19 disease. Inhalation of nanoDEX showed improved anti-inflammatory effects with a lower dose compared to intravenous administration, presenting a safe and effective treatment platform for COVID-19.

The structures, energetics, spectroscopies and stability of the doublet [Si, C, P, O] radical are explored at the density functional theory and ab initio levels. Eighteen isomers connected by 22 interconversion transition states are located at the DFT/B3LYP/6-311G(d) level. The structures of the kinetically stable isomers and the relevant transition states are further optimized at the QCISD/6-311G(d) level followed by CCSD(T)/6-311 + G(2df) single-point energy calculations. At the QCISD/6-311G(d) level, the lowest-lying isomer is the cyclic O-cCSiP 8 (0.0 kcal/mol) with considerable kinetic stability of 22.0 kcal/mol. In addition, two bent isomers OSiCP 1 (7.3 kcal/mol) and SiCPO 3 (34.7 kcal/mol) also possess considerable kinetic stability (more than 10.0 kcal/mol). As a result, three isomers 1, 3 and 8 are predicted to be possible candidates for future experimental and astrophysical detection. The bonding nature of the three isomers is analysed. The calculated results are compared with those of the analogous radical [Si, C, N, O]. Implications in the laboratory and interstellar space are also discussed. The predicted structures and spectroscopic properties are expected to be informative for the identification of [Si, C, P, O] in the laboratory and space. [ABSTRACT FROM AUTHOR]

Various levels of calculations are carried out~for exploring the potential energy surface (PES) of triplet SiC3O, a molecule of potential interest in interstellar chemistry. A total of 38 isomers are located on the PES including chain-like, cyclic and cage-like structures, which are connected by 87 interconversion transition states at the DFT/B3LYP/6-311G(d) level. The structures of the most relevant isomers and transition states are further optimized at the QCISD/6-311G(d) level followed by CCSD(T)/6-311+G(2df) single-point energy calculations. At the QCISD level, the lowest lying isomer is a linear SiCCCO 1 (0.0 kcal/mol) with the 3 ∑ electronic state, which possesses great kinetic stability of 59.5 kcal/mol and predominant resonant structure [MediaObject not available: see fulltext.]. In addition, the bent isomers CSiCCO 2 (68.3 kcal/mol) and OSiCCC 5 (60.1 kcal/mol) with considerable kinetic stability are also predicted to be candidates for future experimental and astrophysical detection. The bond natures and possible formation pathways in interstellar space of the three stable isomers are discussed. The predicted structures and spectroscopic properties for the relevant isomers are expected to be informative for the identification of SiC3O and even larger SiC n O species in laboratory and interstellar medium. [ABSTRACT FROM AUTHOR]

Various levels of calculations are carried out to explore the potential energy surfaces (PES) of singlet and triplet SiC3S, a molecule of potential interest in interstellar chemistry. At the DFT/B3LYP/6-311G(d) level, a total of 57 minimum isomers and 92 interconversion transition states are located. The structures of the most relevant isomers and transition states are further optimized at the QCISD/6-311G(d) level followed by CCSD(T)/6-311 + G(2df) single-point energy calculations. At the QCISD level, the lowest-lying isomer is the chain-like SiCCCS 31 (0.0 kcal/mol) with a great kinetic stability of 54.1 kcal/mol. In addition, ring isomers CC-cCSSi 19 (19.8 kcal/mol), S-cCCCSi 112 (30.4 kcal/mol), S-cCCSiC 118 (9.4 kcal/mol), S-cSiCCC 121 (34.4 kcal/mol) and cage-like isomer cage-SiSCCC 123 (51.8 kcal/mol) also possess considerable kinetic stability (more than 10.0 kcal/mol). As a result, these six isomers are predicted to be possible candidates for future experimental and astrophysical detection. The bond natures and possible formation pathways in interstellar space of the SiCCCS are discussed. The predicted structure and spectroscopic properties for it are expected to be informative for the identification of SiC3S and even larger SiCnS species either in laboratory or in space. [ABSTRACT FROM AUTHOR]

Background: NLRP3 inflammasome acts as a danger signal sensor that triggers and coordinates the inflammatory response. However, the roles of NLRP3 inflammasome in the tumorigenesis and development of cancer stem cells (CSCs) of squamous cell carcinoma of the head and neck (SCCHN) remain ambiguous. Methods: In our study, tissue microarrays, ELISA, sphere-forming assay, colony formation assay and Western blot analysis were performed to evaluate the effect of NLRP3 inflammasome on the development of CSCs in human SCCHN tissue specimen, cell lines, and transgenic mouse SCCHN model. Results: The components of NLRP3 inflammasome, namely, NLRP3, ASC, Caspase-1, and IL-18 were correlated with CSCs markers BMI1, ALDH1 and CD44 in human SCCHN specimens. Moreover, NLRP3, Caspase-1, IL-1β, and IL-18 were highly expressed in SCCHN cell lines. NLRP3 inflammasome activated by LPS and ATP promoted sphere-forming and colony formation capacities along with an upregulation of BMI1, ALDH1 and CD44. In addition, NLRP3 inflammasome blockade by NLRP3 inhibitor MCC950 reduced sphere and colony number, also decreased the expression of BMI1, ALDH1 and CD44 in SCCHN cell lines. Expression of NLRP3, ASC, Caspase-1, IL-1β, IL-18, BMI1, ALDH1 and CD44 was upregulated in Tgfbr1/Pten 2cKO mouse SCCHN model, and NLRP3 inflammasome expression was closely related to those CSCs makers in mice SCCHN. However, MCC950 treatment reduced the expression of NLRP3 inflammasome, CSCs markers BMI1, ALDH1 and CD44 in Tgfbr1/Pten 2cKO mice SCCHN. In addition, blockade of NLRP3 inflammasome can also delayed the tumor-burdened speed in SCCHN mice. Conclusions: Our study demonstrates that NLRP3 inflammasome was upregulated and associated with the carcinogenesis and CSCs self-renewal activation in SCCHN. NLRP3 inflammasome can be a potential target in the development of novel approaches for head and neck squamous cell carcinoma therapy. [ABSTRACT FROM AUTHOR]

Background: Cancer immunotherapy offers a promising approach in cancer treatment. The adenosine A2A receptor (A2AR) could protect cancerous tissues from immune clearance via inhibiting T cells response. To date, the role of A2AR in head and neck squamous cell carcinoma (HNSCC) has not been investigated. Here, we sought to explore the expression and immunotherapeutic value of A2AR blockade in HNSCC. Methods: The expression of A2AR was evaluated by immunostaining in 43 normal mucosae, 48 dysplasia and 165 primary HNSCC tissues. The immunotherapeutic value of A2AR blockade was assessed in vivo in genetically defined immunocompetent HNSCC mouse model. Results: Immunostaining of HNSCC tissue samples revealed that increased expression of A2AR on tumor infiltrating immune cells correlated with advanced pathological grade, larger tumor size and positive lymph node status. Elevated A2AR expression was also detected in recurrent HNSCC and HNSCC tissues with induction chemotherapy. The expression of A2AR was found to be significantly correlated with HIF-1α, CD73, CD8 and Foxp3. Furthermore, the increased population of CD4+Foxp3+ regulatory T cells (Tregs), which partially expressed A2AR, was observed in an immunocompetent mouse model that spontaneously develops HNSCC. Pharmacological blockade of A2AR by SCH58261 delayed the tumor growth in the HNSCC mouse model. Meanwhile, A2AR blockade significantly reduced the population of CD4+ Foxp3+ Tregs and enhanced the anti-tumor response of CD8+ T cells. Conclusions: These results offer a preclinical proof for the administration of A2AR inhibitor on prophylactic experimental therapy of HNSCC and suggest that A2AR blockade can be a potential novel strategy for HNSCC immunotherapy. [ABSTRACT FROM AUTHOR]

The nitrogen edge-doped effect on the structure, dipole moment, and first hyperpolarizability of the supershort single-walled carbon nanotube (5, 0) has been studied systematically. For the nitrogen edge-doped effect on the structure, the mean diameter on the nitrogen-doped side (Du) decreases as the number of doped-nitrogen (n) increases (4.044 (1) > 3.991 (2) > 3.941 (3) > 3.891 (4) > 3.844 Å (5)). Significantly, the nitrogen edge-doped effects on the dipole moment and first hyperpolarizability are revealed for the first time and these new effects are dramatic for the supershort single-walled carbon nanotube (5, 0). Among the β0 values of these seven nitrogen-doped structures, the largest β0 (3155 au) is larger by almost 450 times than the very small β0 (7 au) of undoped structure (D5h). For nitrogen-doped structures, the order of the β0 values is 3155 (1) > 2677 (2A) ≈ 2817 (2B) > 1465 (3A) ≈ 1458 (3B) > 670 (4) > 254 au (5), which shows two interesting relationships between the β0 value and nitrogen-doped number: (1) the smaller the nitrogen-doped number, the larger the β0 value. (2) The structures with the same number of doped-nitrogen have almost the same β0 values (1465 for 3A and 1458 au for 3B). As for the frequency-dependent β (-ω; ω, 0) and β (-2ω; ω, ω), the dependence on the nitrogen-doped number (n) is similar to the case of static β0. For β (-2ω; ω, ω) values at ω = 0.005 au are 3220 (1) > 2720 (2A) ≈ 2862 (2B) > 1480 (3A) ≈ 1477 (3B) > 676 (4) > 256 au (5). In addition, the important monotonic dependences of the β value on the Du and electronic spatial extent ≤R2≥ are also observed. The new knowledge of influence the β value will be beneficial to... [ABSTRACT FROM AUTHOR]

Eighteen structures of new organic alkalides (Mn6adz)M‘-(M, M‘ Li, Na, K; n2, 3) with the alkali-metal cation Mlying near the center of the adz cage and the alkali-metal anion M‘-located outside are obtained with all real frequencies. They exhibit very large static first hyperpolarizabilities (0) up to 3.2 × 105au, which exceeds the record value of 01.7 × 105au for nonlinear optical compounds Chem.Eur. J.1997, 3, 1091. All potassides (Mn6adz)K-(M Li, Na, K; n2, 3) have considerably large 0values (1.6 × 105−3.2 × 105au) much larger than the 0value (3.6 × 104au) of the previously designed cuplike alkalide Li(calix4pyrrole)K-J. Am. Chem. Soc. 2006, 128, 1072. This shows that the 26adz and 36adz cage complexants are preferable to cuplike calix4pyrrole complexant in enhancing the first hyperpolarizability. The effect of cage size of the complexant on the first hyperpolarizability is also presented here:  in most cases, the smaller cage complexant corresponds to the larger 0value. Moreover, the crucial role by the alkali-metal anion in the large first hyperpolarizability of these alkalides is revealed. These results may provide new means for designing high-performance nonlinear optical materials. [ABSTRACT FROM AUTHOR]

Nanotechnology possesses the potential to revolutionize the diagnosis and treatment of tumors. The ideal nanoparticles used for in vivo cancer therapy should have long blood circulation times and active cancer targeting. Additionally, they should be harmless and invisible to the immune system. Here, we developed a biomimetic nanoplatform with the above properties for cancer therapy. Macrophage membranes were reconstructed into vesicles and then coated onto magnetic iron oxide nanoparticles (Fe3O4 NPs). Inherited from the Fe3O4 core and the macrophage membrane shell, the resulting Fe3O4@MM NPs exhibited good biocompatibility, immune evasion, cancer targeting and light-to-heat conversion capabilities. Due to the favorable in vitro and in vivo properties, biomimetic Fe3O4@MM NPs were further used for highly effective photothermal therapy of breast cancer in nude mice. Surface modification of synthetic nanomaterials with biomimetic cell membranes exemplifies a novel strategy for designing an ideal nanoplatform for translational medicine. [ABSTRACT FROM AUTHOR]