A GI/Geo/1 queue with negative and positive customers

The arrival of a negative customer to a queueing system causes one positive customer to be removed if any is present. Continuous-time queues with negative and positive customers have been thoroughly investigated over the last two decades. On the other hand, a discrete-time Geo/Geo/1 queue with negative and positive customers appeared only recently in the literature. We extend this Geo/Geo/1 queue to a corresponding GI/Geo/1 queue. We present both the stationary queue length distribution and the sojourn time distribution.     

On the temporal decay for the Hall-magnetohydrodynamic equations

We establish temporal decay estimates for weak solutions to the Hall-magnetohydrodynamic equations. With these estimates in hand we obtain algebraic time decay for higher order Sobolev norms of small initial data solutions.     

Band gap tunable and improved microstructure characteristics of Cu2ZnSn(S1−x,Sex)4 thin films by annealing under atmosphere containing S and Se

Cu₂ZnSn(S_xS_1?x)₄ (CZTSSe) thin films were prepared by annealing a stacked precursor prepared on Mo coated glass substrates by the sputtering technique. The stacked precursor thin films were prepared from Cu, SnS₂, and ZnS targets at room temperature with stacking orders of Cu/SnS₂/ZnS. The stacked precursor thin films were annealed using a tubular two zone furnace system under a mixed N₂ (95%) + H₂S (5%) + Se vaporization atmosphere at 580 °C for 2 h. The effects of different Se vaporization temperature from 250 °C to 500 °C on the structural, morphological, chemical, and optical properties of the CZTSSe thin films were investigated. X-ray diffraction patterns, Raman spectroscopy, and X-ray photoelectron spectroscopy results showed that the annealed thin films had a single kesterite crystal structure without a secondary phase. The 2θ angle position for the peaks from the (112) plane in the annealed thin films decreased with increasing Se vaporization temperature. Energy dispersive X-ray results showed that the presence of Se in annealed thin films increased from 0 at% to 42.7 at% with increasing Se vaporization temperatures. UV–VIS spectroscopy results showed that the absorption coefficient of all the annealed thin films was over 10⁴ cm^?1 and that the optical band gap energy decreased from 1.5 eV to 1.05 eV with increasing Se vaporization temperature.     

Conditions on the Pressure for Vanishing Velocity in the Incompressible Fluid Flows in ℝ N

In this paper we derive various sufficient conditions on the pressure for vanishing velocity in the incompressible Navier-Stokes and the Euler equations in ? ^N .     

Influence of un-cured PDMS chains in stamp using PDMS-based lithography

We present the compatibility of elastomeric stamp, poly(dimethylsiloxane) (PDMS), with inks for non-photolithography. This ink limitation is important in considering the lamination of hydrophilic solution on the patterned ink surface using an elastomeric stamp. We focus on an increase of the hydrophobicity of the patterned surface due to diffusion of low molecular weight (LMW) silicone polymer chains. This hydrophobicity increases inversely with the PDMS–ink interaction parameter (χ), which is correlated with the solubility parameter (δ). This study's results translate into proposed design factors for ink used in the patterned functional layer for PDMS-based lithography. Both the XPS and the contact angle measurement show that the hydrophobicity can be increased by LMW PDMS chains transfer from stamps, and this increase can cause the expansion of the free volume in PDMS pores through a swelling effect.     

Synthesis of Moracin C and Its Derivatives with a 2-arylbenzofuran Motif and Evaluation of Their PCSK9 Inhibitory Effects in HepG2 Cells

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a key factor in several cardiovascular diseases, as it is responsible for the elevation of circulating low-density lipoprotein cholesterol (LDL-C) levels in blood plasma by direct interaction with the LDL receptor. The development of orally available drugs to inhibit this PCSK9-LDLR interaction is a highly desirable objective. Here, we report the synthesis of naturally occurring moracin compounds and their derivatives with a 2-arylbenzofuran motif to inhibit PCSK9 expression. In addition, we discuss a short approach involving the three-step synthesis of moracin C and a divergent method to obtain various analogs from one starting material. Among the tested derivatives, compound 7 (97.1%) was identified as a more potent inhibitor of PCSK9 expression in HepG2 cells than berberine (60.9%). These results provide a better understanding of the structure–activity relationships of moracin derivatives for the inhibition of PCSK9 expression in human hepatocytes.     

Self-Assembly Behavior and Application of Terphenyl-Cored Trimaltosides for Membrane-Protein Studies: Impact of Detergent Hydrophobic Group Geometry on Protein Stability

Amphipathic agents are widely used in various fields including biomedical sciences. Micelle-forming detergents are particularly useful for in vitro membrane-protein characterization. As many conventional detergents are limited in their ability to stabilize membrane proteins, it is necessary to develop novel detergents to facilitate membrane-protein research. In the current study, we developed novel trimaltoside detergents with an alkyl pendant-bearing terphenyl unit as a hydrophobic group, designated terphenyl-cored maltosides (TPMs). We found that the geometry of the detergent hydrophobic group substantially impacts detergent self-assembly behavior, as well as detergent efficacy for membrane-protein stabilization. TPM-Vs, with a bent terphenyl group, were superior to the linear counterparts (TPM-Ls) at stabilizing multiple membrane proteins. The favorable protein stabilization efficacy of these bent TPMs is likely associated with a binding mode with membrane proteins distinct from conventional detergents and facial amphiphiles. When compared to n-dodecyl-β-d -maltoside (DDM), most TPMs were superior or comparable to this gold standard detergent at stabilizing membrane proteins. Notably, TPM-L3 was particularly effective at stabilizing the human β₂ adrenergic receptor (β₂AR), a G-protein coupled receptor, and its complex with G_s protein. Thus, the current study not only provides novel detergent tools that are useful for membrane-protein study, but also suggests a critical role for detergent hydrophobic group geometry in governing detergent efficacy.     

Enthalpic effect of polyacrylonitrile on the concentrated solutions in dimethyl sulfoxide: Strong thixotropic behavior and formation of bound solvents

The effect of dipole–dipole interaction by nitrile groups of PAN on the bound state of solvent molecules and the concentrated solution properties in DMSO was investigated. Variation of a solution viscosity exhibited three overlap concentrations, C1*, C2*, and C3*, at 2.7, 8.6, and 16.3 wt%, respectively, representing the transition of concentration regions in the order of dilute, unentangled‐semi dilute, entangled‐semi dilute, and concentrated regions. The two‐dimensional mapping of FT‐IR analysis and dielectric measurement confirmed that the intermolecular interaction of PAN was suddenly enhanced at the C*s, inducing polarization to DMSO. In the ice‐melting process of PAN solutions, two different melting peaks (T_m2 and T_m3) of DMSO newly appeared at each C2* and C3*, suggesting the different types of bound solvents. In the concentrated solutions, the saturated dielectric constant and the strongly delayed evaporation of the solvent even at the boiling point of DMSO along with strong thixotropic behavior were indicative of the stronger confinement state of bound DMSO than in the semidilute solutions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1080–1089