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The PD-L1/PD-1 pathway is a critical component of the immunosuppressive tumor microenvironment in acute myeloid leukemia (AML), but little is known about its regulation. We investigated the role of the MUC1 oncoprotein in modulating PD-L1 expression in AML. Silencing of MUC1 in AML cell lines suppressed PD-L1 expression without a decrease in PD-L1mRNA levels, suggesting a post-transcriptional mechanism of regulation. We identified the microRNAs miR-200c and miR-34a as key regulators of PD-L1 expression in AML. Silencing of MUC1 in AML cells led to a marked increase in miR-200c and miR-34a levels, without changes in precursor microRNA, suggesting that MUC1 might regulate microRNA-processing. MUC1 signaling decreased the expression of the microRNA-processing protein DICER, via the suppression of c-Jun activity. NanoString (Seattle, WA, USA) array of MUC1-silenced AML cells demonstrated an increase in the majority of probed microRNAs. In an immunocompetent murine AML model, targeting of MUC1 led to a significant increase in leukemia-specific T cells. In concert, targeting MUC1 signaling in human AML cells resulted in enhanced sensitivity to T-cell-mediated lysis. These findings suggest MUC1 is a critical regulator of PD-L1 expression via its effects on microRNA levels and represents a potential therapeutic target to enhance anti-tumor immunity.

Nematic fluctuations and order play a prominent role in material classes such as the cuprates, some ruthenates or the iron-based compounds and may be interrelated with superconductivity. In iron-based compounds signatures of nematicity have been observed in a variety of experiments. However, the fundamental question as to the relevance of the related spin, charge or orbital fluctuations remains open. Here, we use inelastic light (Raman) scattering and study Ba(Fe1−xCox)2As2(0 ≤ x ≤ 0.085) for getting direct access to nematicity and the underlying critical fluctuations with finite characteristic wavelengths. We show that the response from fluctuations appears only in B1g(x2− y2) symmetry (1 Fe unit cell). The scattering amplitude increases towards the structural transition at Tsbut vanishes only below the magnetic ordering transition at TSDW< Ts, suggesting a magnetic origin of the fluctuations. The theoretical analysis explains the selection rules and the temperature dependence of the fluctuation response. These results make magnetism the favourite candidate for driving the series of transitions.

In recent years the magnetism demonstrated in undoped oxide and sulfide semiconductor nanoparticles was intensively studied for the potential applications in nanoscale science. First-principles calculations were performed to investigate the magnetic properties, Heisenberg exchange interaction, and Curie temperature (Tc) of cadmium sulfide (CdS) nanoclusters (NCs) in this work. Our calculations indicate that spin-polarized states are always energetically favorable and that the induced magnetism mainly originates from the dangling bond spins of those two-coordinate S anions located on the S-terminated surface, which is perpendicular to c-axis. Meanwhile, the CdS NCs driven magnetism can be completely destroyed with hydrogen passivation. The calculated Heisenberg exchange interaction and Tcshow oscillatory behaviors. The Hubbard model theory can be used to account for the interactions between the dangling bond spins in CdS NCs. These results suggest that CdS NCs may be a promising material for nanoscale magneto-optical devices.

Bismuth trioxide (Bi2O3) ultrathin films were successfully synthesized on silicon substrates by means of atomic layer deposition (ALD) using Bi(thd)3(thd: 2,2,6,6-tetramethyl-3,5-heptanedionato) and H2O as precursors. The optimum ALD window was about 270–300 °C, and an ALD-type growth mechanism via surface saturation reaction was identified; the growth rate was about 0.1 Å/cycle. The X-ray diffraction and high-resolution transmission electron microscopy investigation revealed that Bi2O3films crystallized into a predominant alpha phase above 250 °C. The resistivity at room temperature was about 1.2 × 106Ω·cm, which is also proof of the α-phase of as-deposited Bi2O3films. In addition, a new method to obtain γ-Bi2O3film was discovered. The α-Bi2O3films (synthesized by ALD) transformed into metastable γ-Bi2O3with preferred orientation (222) after annealing above 512 °C, and γ-phase could persist at room temperature.

Bismuth ferrite (BiFeO3) nanocrystalline films with the crystalline size of 27-40 nm have been grown on c-sapphire substrates under various oxygen pressures of 1 × 10–4to 1 Pa by pulsed laser deposition. The X-ray diffraction spectra show that the films are polycrystalline and present the pure rhombohedral phase. It was found that the Raman-active phonon mode E(TO1) shifts towards a higher energy side from 74 to 76 cm–1with increasing oxygen pressure, indicating a larger tensile stress in the films deposited at higher oxygen pressure. The X-ray photoelectron spectroscopy analysis suggests that the concentrations of both Fe2+ions and oxygen vacancies in the BiFeO3films increase with decreasing oxygen pressure. Moreover, the dielectric functions in the photon energy range of 0.47–6.5 eV have been extracted by fitting the transmittance spectra with the Tauc-Lorentz dispersion model. From the transmittance spectra, the fundamental absorption edge is observed to present a redshift trend with increasing the temperature from 8 to 300 K. Note that the optical band gap (Eg) decreases with increasing the temperature due to the electron-phonon interactions associated with the interatomic distance in the BiFeO3films. However, the Egdecreases from 2.88 to 2.78 eV with decreasing oxygen pressure at 8 K, which can be attributed to the increment of oxygen vacancies leading to the formation of some impurity states between the valence and conduction band. It can be concluded that the oxygen pressure during the film fabrication has the significant effects on microstructure, optical properties, and electronic band structure modification of the BiFeO3films.

Despite the intensive study on the famous metal–insulator transition, many questions regarding the evolution of the structural phase transition (SPT) in vanadium dioxide (VO2) remain unresolved. Here, the lattice vibrations and SPT of VO2nanoparticles on a SiO2/Si(100) substrate with different applied voltage from 0 to 8 V have been investigated by Raman scattering spectra. It can be found that both the intensities of the Agand Bgphonon modes decrease with increasing temperature. Moreover, the vibration modes disappear when heating up to the temperature of SPT (TSPT). With the voltage increasing from 0 to 8 V, the TSPTdecreases from 68.3 to 64.3 °C for the heating process and from 66.3 to 58.8 °C for the cooling process, respectively. The fitting results reveal that the TSPTwas decreased by −0.48 and −0.87 °C/V in the heating and cooling processes, respectively. This is because the larger electric field could assist the shortening of the V–V distance and the change of carriers between electrons and the mixing of electrons and holes. Moreover, the TSPTdelay was increased by 0.4 °C/V with increasing the positive voltage because the electric field can pull the electrons and push the holes. The present results of the VO2three-terminal device show a potential realization of the VO2-based field effect transistor.

Spectroscopic ellipsometry was used to extract the optical properties of Ba0.4Sr0.6-xMnxTiO3(BSMT) (xfrom 1% to 20%) ceramics in the 0.7-4.7 eV (260-1700 nm) photon energy range at room temperature. X-ray diffraction analysis showed that BSMT ceramics are polycrystalline and lattice constants with different Mn composition present a slight variation. By reproducing the experimental ellipsometric spectra ( and ), the optical constants and optical band gap energy have been obtained. It was found that the refractive index n increases first and then decreases as the photon energy increases from 0.7 to 4.7 eV for all the samples. The extinction coefficient kincreases with increasing photon energy. On the other hand, both nand kdecrease with increasing doping level of Mn (x≤ 5%). Direct optical band gap energy is estimated to be 3.45-3.71 eV owing to different Mn doping. The difference of the optical properties can be ascribed to structure distortion with different Mn composition. The present results could be useful for future application of (Ba,Sr)TiO3-based optoelectronic devices.

Near-infrared-ultraviolet optical properties of Sn0.925Mn0.075O2(SMO) film grown on c-plane sapphire substrate have been investigated by the transmittance spectra in the photon energy of 0.45-6.5 eV (190-2650 nm) from 5.3-300 K. The optical constants have been extracted by fitting the experimental data with the Adachi's model. The optical band gap of the film can be estimated from the relation (E)2proportional to(h-Eg). It is found that the absorption edge shifts to a lower energy side with increasing the temperature and the band gap Egdecreases from 3.80 to 3.72 eV. The parameters Band Bof the Bose-Einstein model are 45.4 meV and 221.8 K, respectively, which could be ascribed to the thermal expansion of crystal lattice and the carrier-phonon interaction. The band narrowing coefficient dEg/dTof the SMO film is estimated to be -3.92x10-4eV/K at room temperature.

Iron-doped titanium dioxide nanocrystalline (nc-TiO2:Fe) films with the a composition from 2 to 10% have been deposited on Si(100) substrates by a facile nonhydrolytic sol−gel route. X-ray diffraction analysis shows that the films are polycrystalline and exhibit the pure tetragonal rutile phase structure. The Fe dopant effects on the surface morphology, microstructure, phonon modes, and dielectric functions of the nc-TiO2:Fe films have been investigated by atomic force microscopy, ultraviolet Raman scattering, far-infrared reflectance, and spectroscopic ellipsometry at room temperature. With increasing Fe composition, the first-order Raman-active phonon modes Eg, A1g, and B2gare shifted toward a lower frequency side of 10, 6, and 7 cm−1, respectively. The four additional vibrations, which are strongly related to the surface structure of the films, can be observed due to the two-phonon scattering process. Moreover, the three infrared-active transverse-optic (TO) phonon modes Eu(TO) can be located at about 183, 382, and 500 cm−1, respectively. The dielectric functions of the films have been uniquely extracted by fitting the measured ellipsometric spectra with a four-phase layered model (air/surface rough layer/film/Si) in the photon energy range 0.73−4 eV (310−1700 nm). Adachi’s dielectric function model has been successfully applied and reasonably describes the optical response behavior of the nc-TiO2:Fe films from the near-infrared to ultraviolet photon energy region. It is found that the real part of dielectric functions in the transparent region slightly decreases with increasing Fe composition. Furthermore, the optical band gap linearly decreases from 3.43 to 3.39 eV with increasing Fe composition due to the energy level of Fe t2g, which is closer to the valence band. It is believed that the decrease of the optical constants and optical band gap for the nc-TiO2:Fe films with the Fe composition is mainly ascribed to the differences of the crystallinity and the electronic band structure, which can be perturbed by the transition metal introduction.

Manganese-doped tin dioxide (SnO2:Mn) films (grain size of about 16 nm) with different composition xfrom 2.5 to 15% have been grown on quartz substrates by pulsed laser deposition. X-ray diffraction analysis show that the films are polycrystalline and an impurity phase appears until the xis up to 15%. The optical functions in the photon energy range of 0.5−6.5 eV have been extracted by fitting the transmittance spectra at room temperature with the Adachi’s dielectric function model (Adachi, S. Phys. Rev. B1987, 35, 7454). The refractive index generally decreases with the doping composition except for the film doped with 15% Mn because of the variation in crystalline formation and electronic energy band structure. Because of the repelling effect of 2p−3d hybridization and its perturbation on O 2p-like bands, the optical band gap linearly decreases and can be well expressed by (4.26−3.8x) eV. The transmittance spectra of the film doped with 2.5% Mn at the temperature varied from 5.3 to 300 K have been recorded and a redshift trend of the absorption edge with increasing the temperature can be observed. The results indicate that the dielectric functions decrease with the temperature at the photon energies above the fundamental band gap. Moreover, the optical band gap is shrinked from 4.30 to 4.20 eV with increasing the temperature because of the modification of the electron−phonon interactions. The band gap narrowing coefficient of the SnO2:Mn film with 2.5% Mn is estimated to be about −5.74 × 10−4eV/K at room temperature.

Transition-metal-(Cr, Mn, and Ni)-doped zinc oxide (ZnO) with the concentration of 2.5% and pure ZnO nanocrystalline (nc) films have been fabricated on quartz substrates by the sol−gel method. The X-ray diffraction analysis shows that the films are polycrystalline with the wurtzite phase. The E2highphonon mode shifts about 7 cm−1with different transition metals, and the A1(LO) phonon mode redshifts 4 cm−1with the ionic radius of doping elements. From the transmittance spectra, all films are highly transparent in the visible region and exhibit Urbach tail states in the ultraviolet range because of the crystalline defects and grain boundaries. The optical band gap of the films decreases with increasing the orbital occupation numbers of 3d electrons due to the orbital splitting of magnetic ions. It was found that a distinct and strong excitonic transition appears beyond the fundamental absorption region at room temperature. Ultraviolet and near-infrared electronic transitions can be observed and show the strong relationship with the transition metal doping. Moreover, orange, yellow and red luminescences strongly depend on the doping elements owing to different oxygen vacancy, oxygen interstitial, and surface morphology. Magnetic measurement results reveal that all the transition-metal-doped nc-ZnO films show the well-defined ferromagnetic features at room temperature. In particular, the nc-ZnO film doped with Mn shows the largest saturation magnetic moment, which agrees well with the theoretical predication. The ferromagnetic properties could be derived from the doping of magnetic ions, intrinsic defects, interfaces, and grain boundaries in the transition-metal-doped nc-ZnO materials.

Optical properties of Sn1−xMnxO2(xfrom 0.0 to 0.15) nanocrystalline films grown on c-plane sapphire substrates have been investigated at room temperature by ultraviolet-infrared transmittance, far-infrared reflectance, and photoluminescence spectra. The X-ray diffraction analysis indicate that the films are of tetragonal rutile structure except for 5% Mn doping, in which the slight orthorhombic phase appears due to the presence of defects and strain. The dielectric functions are successfully determined from 0.025 to 6.5 eV using the Adachi and Lorentz multioscillator dispersion models in the high and low photon energy regions, respectively. The fundamental absorption edge is found to shift toward a lower energy side with increasing Mn composition. The refractive index of pure SnO2film is estimated to be the lowest among the Sn1−xMnxO2system. On the other hand, the low Eutransverse optical (TO) phonon frequencies slightly increase with the Mn composition. However, the highest Eu(TO) and A2u(TO) vibration modes present an opposite change trend. Compared with SnO2single crystal, four corresponding longitudinal optical (LO) phonon frequencies decrease for the films owing to the variation of the lattice constants and destruction of the crystal symmetry. Photoluminescence spectra of doped SnO2films show the remarkable intensity changes and a blue-shift trend compared to pure SnO2film. Moreover, a novel emission peak of about 1.56 eV associated with the Mn dopant can be observed. It can be concluded that the Mn incorporation effects are the main contributions because the replacement of Sn with Mn ion can induce the 2p−3d hybridization and result in the electronic band structure modification of the Sn1−xMnxO2films.

La0.5Sr0.5CoO3(LSCO) nanocrystalline (nc) films have been directly grown on silicon wafers under different substrate temperatures by pulsed laser deposition. The X-ray diffraction analysis indicate that the films are polycrystalline with the pure perovskite phase at higher substrate temperatures. The columnar growth formation with the nanocrystalline structure in the films has been confirmed by microscopy experiments. Infrared−ultraviolet optical properties of the LSCO films have been investigated with the aid of spectroscopic ellipsometry (SE). Dielectric function in the photon energy range of 1.1−3.1 eV (400−1100 nm) has been extracted by reproducing the experimental data with a Lorentz oscillator model. It is found that the real part is decreased from 4.7 to −0.7 at the near-infrared region with increasing substrate temperature. The optical conductivity shows a different variation trend for the lower and higher growth temperatures, respectively. Note that the films deposited above 650 °C exhibit the well-defined metallic phase behavior. The discrepancies could be mainly ascribed to different crystalline structure and surface morphology. The present results may be crucial for future applications of ferromagnetic-based optoelectronic and spin-electronic devices.

Arsenic (As)-doped (1% to 3%) ZnO nanocrystalline films with the grain size of 20 nm have been grown on silicon substrates by pulsed laser deposition. X-ray diffraction analysis shows that the films are polycrystalline and exhibit the hexagonal wurtzite phase. The As dopant effects on lattice vibrations and electronic transitions of the ZnO films have been investigated by Raman scattering and photoluminescence spectra at room temperature. With increasing As concentration, A1(LO) phonon frequency is shifted toward lower energy side of 4 cm−1. Ultraviolet and near-infrared optical transitions can be observed and remained as a constant. Moreover, orange and green luminescence are strongly dependent on the As concentration owing to different oxygen vacancy, zinc vacancy, oxygen interstitial, and morphology. Dielectric functions of the films have been determined in the photon energy from 2.5 to 6.0 eV by near-normal incident spectral reflectance. By fitting the experimental data with the Adachi’s model, [Adachi, S. Phys. Rev. B1987, 35, 7454] the optical constants and film thickness have been uniquely extracted. It is found that the dielectric function values of the films are less than that of undoped ZnO material, which could be attributed to the As doping and the porosity of films.

Two-dimensional slow viscous flow on infinite half-plane past a perpendicular infinite cavity is considered on the basis of the Stokes approximation. Using complex representation of the two-dimensional Stokes flow, the problem is reduced to solving a set of Fredholm integral equations of the second kind. The streamlines and the pressure and vorticity distribution on the wall are numerically determined.

The numerical procedure for the Navier-Stokes equations developed earlier has been modified to investigate the viscous flow past a circular arc at various positions and Re. Among the major new and improved features are the asymptotic expansion near the tip singularity that takes account of the arc curvature to enlarge the region of its validity and the exit boundary condition that utilizes the Oseen solution to keep the computational domain as small as possible. The details of the flow field, i.e., vorticity, drag, eddy structure, etc., about the semi-circular arc are presented for various Re and angles of incidence. Computations are also performed for arcs of other central angles at incidences of 0° and 90°.

In this paper, the expressions for the effective segregation coefficient and composition depth profile of Hg1-xCdxTe liquid phase epitaxial (LPE) film are presented and compared with the experimental data. The expressions are derived based on the associated solution model and the phase diagram theory of Hg1-xCdxTe. The results show that supercooling, cooling rate, liquid composition, and nonequilibrium Hg pressure over the solution will result in the changes of average composition and composition-depth profile of the grown film. Adequate Hg loss, slow cooling rate, and proper prescription of liquid composition can improve the uniformity of longitudinal composition of Hg1-xCdxTe LPE film.

The phase transitions and the temperature dependent electronic properties of Bi3.25La0.75Ti3O12(BLT) film have been studied by transmittance spectra from 80 to 480 K. Anomalies of the optical constants are observed at 160 K and 300 K, which can be ascribed to the phase transitions. The optical properties of SrBi2-xNdxNb2O9(SBNN) ceramics with the Nd concentrations from 0 to 0.2 have been investigated by Raman scattering spectra and spectroscopic ellipsometry. It can be found that the lattice vibrations slightly depend on the Nd concentrations. Moreover, the optical band gap linearly increases with the Nd concentrations due to charge compensation by the Nd doping.

Anatase Ti1-xFexO2(x=0, 1%, 2%) nanocrystalline films were prepared on quartz substrates by a facile nonhydrolytic sol-gel route. The structure and optical properties have been studied by X-ray diffraction (XRD), Raman scattering, transmittance spectra and temperature dependent photoluminescence (PL). The B1g, Egand (A1g+B1g) modes of anatase phase TiO2can be observed in Raman spectra. Dielectric functions have been extracted by fitting the transmittance spectra in the photon energy range of 0.5-6.5 eV with Adachi's model. The pure TiO2film displays a strong broadening visible luminescence band; however, Fe-doped samples exhibit a very weak luminescence due to the increase of oxygen vacancy concentration in TiO2. With the temperature increases, the PL intensity decreases monotonously and there are five emission peaks for the pure sample in low temperatures, which could be attributed to oxygen vacancies, surface states and F+center.

In this paper we will study the problem of drawing graphs with a minimum number of slopes. We will show that the minimum number of slopes needed to draw a complete graph of n vertices is n. We will also prove that for a complete graph of n vertices to be drawn using only n slopes its vertices must form a convex polygon. Finally, we will present an algorithm which checks whether a complete graph of n vertices can be drawn using only slopes from a given set of n slopes.