A new proof of a theorem of Dembowski

It was shown by P.Dembowski [1;Satz 3] that any finite semiaffine plane(=FSAP) is of the types:

1. A finite affine plane,
2. A finite projective plane with one line and all its points except one deleted,
3. A finite projective plane with one point deleted,
4. A finite projective plane.

This was established by using the results obtained for natural parallelisms of incidence structures. The purpose of this note is to give a new proof based on purely combinatorial arguments.     

Three-dimensional laminar flow and heat transfer in the entrance region of trapezoidal ducts

The laminar convective flow and heat transfer in a duct with a trapezoidal cross-sectional area are studied numerically. The governing equations are solved numerically by a finite volume formulation in complex three-dimensional geometries using co-located variables and Cartesian velocity components. Details of the numerical method are presented. The accuracy of the method was also established by comparing the calculated results with the analytical and numerical results available in the open literature. The Nusselt numbers are obtained for the boundary condition of a uniform wall temperature whereas the friction factors are calculated for no-slip conditions at the walls. The asymptotic values of the Nusselt numbers, friction factors. incremental pressure drops, axial velocity and momentum rate and kinetic energy correction factors approach the available fully developed values. Various geometrical dimensions of the cross-section are considered.     

Electronic structure of crystals: Embedded quantum cluster with overlap

We consider a crystal as partitioned into a localized molecular cluster (containing a defect or not) and an embedding region. Within the Hartree–Fock formalism, an expression is derived for an effective potential due to the embedding region of crystal. This potential is part of the cluster Fock operator and requires input from a perfect crystal calculation. Special features of the derivative are rigorous inclusion of cluster-embedding overlap and orthogonality between single-electron states of the embedding region and the function-space manifold of the cluster; physically correct normalization of the Fock eigenstates; and a nontrivial total-energy algorithm. Computational requirements are qualitatively compared with those for an isolated cluster. The method allows for intracluster (and intraembedding) correlation and can be adapted straightforwardly to local density functional approaches. Fundamental aspects of the embedding problem are addressed in a general formulation that is, nevertheless, oriented toward explicit calculations. © 1995 John Wiley & Sons, Inc.     

Heteroleptic tris-complexes of osmium(III/IV)8-quinolinolates: synthesis,characterization and link-up of oxidation levels

Summary A series of mixed-tris chelates of Os^III and Os^IV of the general formula [OsDQ₂]^0/1+ [D =-ketoenolates (D¹-D³) or tropolonate (D⁴); Q = deprotonated 8-quinolinol] has been prepared and characterized by physico-chemical and spectroscopic methods. In MeCN solution the OsN₂O₄ unit displays reversible Os^IV-Os^III and Os^III-Os^II couples in the ca. - 1.2 to + 0.3 V range versus s.c.e. An irreversible oxidative response corresponding to a higher degree of oxidation is also observed at ca. 1.6 V. The chemistry in different oxidation states is discussed in terms of the electrochemical results.     

In situ Engineering of Tumor-Associated Macrophages via a Nanodrug-Delivering-Drug (β-Elemene@Stanene) Strategy for Enhanced Cancer Chemo-Immunotherapy

Tumor-associated macrophages (TAMs) play a critical role in the immunosuppressive solid tumor microenvironment (TME), yet in situ engineering of TAMs for enhanced tumor immunotherapy remains a significant challenge in translational immuno-oncology. Here, we report an innovative nanodrug-delivering-drug (STNSP@ELE) strategy that leverages two-dimensional (2D) stanene-based nanosheets (STNSP) and β-Elemene (ELE), a small-molecule anticancer drug, to overcome TAM-mediated immunosuppression and improve chemo-immunotherapy. Our results demonstrate that both STNSP and ELE are capable of polarizing the tumor-supportive M2-like TAMs into a tumor-suppressive M1-like phenotype, which acts with the ELE chemotherapeutic to boost antitumor responses. In vivo mouse studies demonstrate that STNSP@ELE treatment can reprogram the immunosuppressive TME by significantly increasing the intratumoral ratio of M1/M2-like TAMs, enhancing the population of CD4⁺ and CD8⁺ T lymphocytes and mature dendritic cells, and elevating the expression of immunostimulatory cytokines in B16F10 melanomas, thereby promoting a robust antitumor response. Our study not only demonstrates that the STNSP@ELE chemo-immunotherapeutic nanoplatform has immune-modulatory capabilities that can overcome TAM-mediated immunosuppression in solid tumors, but also highlights the promise of this nanodrug-delivering-drug strategy in developing other nano-immunotherapeutics and treating various types of immunosuppressive tumors.     

Simultaneous extraction and quantification of lamotrigine,phenobarbital, and phenytoin in human plasma and urine samples using solidified floating organic drop microextraction and high‐performance liquid chromatography

A novel and simple method based on solidified floating organic drop microextraction followed by high‐performance liquid chromatography with ultraviolet detection has been developed for simultaneous preconcentration and determination of phenobarbital, lamotrigine, and phenytoin in human plasma and urine samples. Factors affecting microextraction efficiency such as the type and volume of the extraction solvent, sample pH, extraction time, stirring rate, extraction temperature, ionic strength, and sample volume were optimized. Under the optimum conditions (i.e. extraction solvent, 1‐undecanol (40 μL); sample pH, 8.0; temperature, 25°C; stirring rate, 500 rpm; sample volume, 7 mL; potassium chloride concentration, 5% and extraction time, 50 min), the limits of detection for phenobarbital, lamotrigine, and phenytoin were 1.0, 0.1, and 0.3 μg/L, respectively. Also, the calibration curves for phenobarbital, lamotrigine, and phenytoin were linear in the concentration range of 2.0–300.0, 0.3–200.0, and 1.0–200.0 μg/L, respectively. The relative standard deviations for six replicate extractions and determinations of phenobarbital, lamotrigine, and phenytoin at 50 μg/L level were less than 4.6%. The method was successfully applied to determine phenobarbital, lamotrigine, and phenytoin in plasma and urine samples.     

A numerical study on the absorption of water vapor into a film of aqueous LiBr falling along a vertical plate

Absorber is an important component in absorption machines and its characteristics have significant effects on the overall efficiency of absorption machines. This article reports a model of simultaneous heat and mass transfer process in absorption of refrigerant vapor into a lithium bromide solution of water––cooled vertical plate absorber in the Reynolds number range of 5 < Re < 150. The boundary layer assumptions were used for the transport of mass, momentum and energy equations and the fully implicit finite difference method was employed to solve the governing equations in the film flow. Dependence of lithium bromide aqueous properties to the temperature and concentration and film thickness to vapor absorption was employed. This model can predict temperature, concentration and properties of aqueous profiles as well as the absorption heat and mass fluxes, heat and mass transfer coefficients, Nusslet and Sherwood number of absorber. An analysis for linear distribution of wall temperature condition carries out to investigation the reliability of the present numerical method through comparing with previous investigation.     

Dynamics of Optical Switching and Stability Analysis of a Polarization Bistable Laser Diode with Detuned External Light Injection

Dynamic behaviors of a polarization-bistable laser diode with detuned light injection are studied, including slow, fast and overshoot switching processes. Dependences of switching time of optical outputs between locked and free oscillating modes on the detuning and power of optical input, carrier injection rate and cross-gain saturation coefficients are investigated. Based on linear stability analysis the system stability is analyzed and analytical expressions are developed to predict the switching time. Our analytical results, in which the switching of optical output from locked to unlocked modes is shown to be composed of two relaxation processes with short and long time constants, are in agreement with the numerical results showing fast and slow switching behaviors dependent on the initial locked state, in contrast to the dynamic behavior of the carrier density dominated by a single relaxation process.