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161.
In this paper, we study the class of graphs defined by excluding the following structures as induced subgraphs: theta, pyramid, 1-wheel, and 3-wheel. We describe the structure of graphs in , and we give a polynomial-time recognition algorithm for this class. We also prove that -free graphs in are 4-colorable. We remark that includes the class of chordal graphs, as well as the class of line graphs of triangle-free graphs. 相似文献
162.
Pham Vu Nhat Nguyen Thanh Si Nguyen Thi Thu Tram Long Van Duong Minh Tho Nguyen 《Journal of computational chemistry》2020,41(19):1748-1758
Density functional theory methods were employed to clarify the adsorption/desorption behaviors of the thione-containing mercaptopurine and thioguanine drugs on the gold surface using both small Au6 and Au8 clusters as model reactants. Structural features, thermodynamic parameters, bonding characteristics, and electronic properties of the resulting complexes were investigated using the Perdew–Burke–Ernzerhof (PBE) and LC-BLYP functionals along with correlation-consistent basis sets, namely cc-pVDZ-PP for gold and cc-pVTZ for non-metals. Computed results show that the drug molecules tend to anchor on the gold cluster at the S atom with binding energies around −34 to −40 kcal/mol (in vacuum) and − 28 to −32 kcal/mol (in aqueous solution). As compared to Au8, Au6 undergoes a shorter recovery time and a larger change of energy gap that could be converted to an electrical signal for selective detection of the drugs. Furthermore, interactions between the drugs and gold clusters are reversible processes and a drug release mechanism was also proposed. Accordingly, the drugs are able to separate from the gold surface due to either a slight change of pH in tumor cells or the presence of cysteine residues in protein matrices. 相似文献
163.
Robert J. Messinger Tan Vu Huynh Renaud Bouchet Vincent Sarou-Kanian Michaël Deschamps 《Magnetic resonance in chemistry : MRC》2020,58(11):1118-1129
Magic-angle-spinning (MAS) enhances sensitivity and resolution in solid-state nuclear magnetic resonance (NMR) measurements. MAS is obtained by aerodynamic levitation and drive of a rotor, which results in large centrifugal forces that may affect the physical state of soft materials, such as polymers, and subsequent solid-state NMR measurements. Here, we investigate the effects of MAS on the solid-state NMR measurements of a polymer electrolyte for lithium-ion battery applications, poly(ethylene oxide) (PEO) doped with the lithium salt LiTFSI. We show that MAS induces local chain ordering, which manifests itself as characteristic lineshapes with doublet-like splittings in subsequent solid-state 1 H, 7 Li, and 19 F static NMR spectra characterizing the PEO chains and solvated ions. MAS results in distributions of stresses and hence local chain orientations within the rotor, yielding distributions in the local magnetic susceptibility tensor that give rise to the observed NMR anisotropy and lineshapes. The effects of MAS were investigated on solid-state 7 Li and 19 F pulsed-field-gradient (PFG) diffusion and 7Li longitudinal relaxation NMR measurements. Activation energies for ion diffusion were affected modestly by MAS. 7Li longitudinal relaxation rates, which are sensitive to lithium-ion dynamics in the nanosecond regime, were essentially unchanged by MAS. We recommend that NMR researchers studying soft polymeric materials use only the spin rates necessary to achieve the desired enhancements in sensitivity and resolution, as well as acquire static NMR spectra after MAS experiments to reveal any signs of stress-induced local ordering. 相似文献
164.
165.
Minh Thang Le Hong Lien Nguyen Anh‐Tuan Vu Van Chuc Nguyen Jeffrey C. S. Wu 《中国化学会会志》2019,66(12):1713-1720
TiO2 loaded on several substrates such as carbon fiber, aluminum plate, silica plate, and glass plate was prepared using the chemical vapor deposition (CVD) method for the photocatalytic reduction of Cr(VI) in water with the presence of ethanol under Ultraviolet (UV) illumination. As‐prepared samples were characterized by X‐Ray Diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM). The catalyst with TiO2 loaded on carbon fiber possessed an extremely large surface area (1,463,91 m2/g), while the other catalysts possessed small surface areas (0.05–0.21 m2/g). The photocatalytic activity of TiO2 loaded on carbon fiber, which was determined by the conversion of Cr(VI) and the degradation of chemical oxygen demand (COD), was much higher than that of other catalysts. The reusability of TiO2 loaded on carbon fiber catalyst exhibited almost the same activity as the fresh catalyst. The results indicated that TiO2 loaded on carbon fiber is feasible for practical application. 相似文献
166.
Let D be a division ring with center F and K a division subring of D. In this paper, we show that a non-central normal subgroup N of the multiplicative group
$$D^*$$
is left algebraic over K if and only if so is D provided F is uncountable and contained in K. Also, if K is a field and the n-th derived subgroup
$$D^{(n)}$$
of
$$D^{*}$$
is left algebraic of bounded degree d over K, then
$$\dim _FD\le d^2$$
. 相似文献
167.
We prove estimates, , for solutions to the tangential Cauchy–Riemann equations on a class of infinite type domains . The domains under consideration are a class of convex ellipsoids, and we show that if is a ‐closed (0,1)‐form with coefficients in , then there exists an explicit solution u satisfying . Moreover, when , we show that there is a gain in regularity to an f‐Hölder space. We also present two applications. The first is a solution to the ‐equation, that is, given a smooth (0,1)‐form ? on with an L1‐boundary value, we can solve the Cauchy–Riemann equation so that where C is independent of and ?. The second application is a discussion of the zero sets of holomorphic functions with zero sets of functions in the Nevanlinna class within our class of domains. 相似文献
168.
169.
Dr. Dong‐Sik Shin Dr. Jungmok You Ali Rahimian Tam Vu Christian Siltanen Arshia Ehsanipour Dr. Gulnaz Stybayeva Prof. Julie Sutcliffe Prof. Alexander Revzin 《Angewandte Chemie (International ed. in English)》2014,53(31):8221-8224
Cells may be captured and released using a photodegradable hydrogel (photogel) functionalized with antibodies. Photogel substrates were used to first isolate human CD4 or CD8 T‐cells from a heterogeneous cell suspension and then to release desired cells or groups of cells by UV‐induced photodegradation. Flow cytometry analysis of the retrieved cells revealed approximately 95 % purity of CD4 and CD8 T‐cells, suggesting that this substrate had excellent specificity. To demonstrate the possibility of sorting cells according to their function, photogel substrates that were functionalized with anti‐CD4 and anti‐TNF‐α antibodies were prepared. Single cells captured and stimulated on such substrates were identified by the fluorescence “halo” after immunofluorescent staining and could be retrieved by site‐specific exposure to UV light through a microscope objective. Overall, it was demonstrated that functional photodegradable hydrogels enable the capture, analysis, and sorting of live cells. 相似文献
170.
C. E. Johnson M. Vu J. A. Johnson D. E. Brown J. K. R. Weber C. Paßlick S. Schweizer 《Hyperfine Interactions》2014,226(1-3):797-801
A fluorozirconate glass (ZBLAN) containing BaCl 2 nanocrystals doped with divalent Eu is a promising material for x-ray image plates for medical diagnosis. Since it is known that Eu 2+ readily oxidizes to Eu 3+, which reduces fluorescence efficiency of the image plates, 151Eu Mössbauer spectroscopy was used in this work to monitor the Eu oxidation state of the samples during degradation over time in the presence of ambient humidity. In addition, Mössbauer spectroscopic experiments show that the oxidation state has already changed during the glass melt: The sample made from 5 mol% EuCl 2 contained 78 % EuCl 2 + 22 % EuCl 3 deduced from the relative areas of the absorption lines. The sample made from 2.5 mol% EuCl2 + 2.5 mol% EuCl2 contained 37 % EuCl2 + 63 % EuCl3, i.e. 26 % of the original EuCl 2 was oxidized to EuCl 3. 相似文献