Equilibrium customer strategies in a single server Markovian queue with setup times

We consider a single server Markovian queue with setup times. Whenever this system becomes empty, the server is turned off. Whenever a customer arrives to an empty system, the server begins an exponential setup time to start service again. We assume that arriving customers decide whether to enter the system or balk based on a natural reward-cost structure, which incorporates their desire for service as well as their unwillingness to wait. We examine customer behavior under various levels of information regarding the system state. Specifically, before making the decision, a customer may or may not know the state of the server and/or the number of present customers. We derive equilibrium strategies for the customers under the various levels of information and analyze the stationary behavior of the system under these strategies. We also illustrate further effects of the information level on the equilibrium behavior via numerical experiments.      

Adsorption of procaine at the mercury/electrolyte solution interface

The adsorption of the local anaesthetic procaine hydrochloride at the mercury/electrolyte interface solution is followed using capacitance measurements. The adsorption is studied at various procaine concentrations, in potassium chloride, potassium bromide or potassium fluoride used as supporting electrolytes, and at various pH values and temperatures. Procaine has basic properties with two acidity constants K. The results indicate the way the procaine molecules orientate at the interface. In all cases studied no hemimicelles or condensed film are observed.     

Structure, stability, and quantum conductivity of small diameter silicon nanowires

Structures and energetics of various types of silicon nanowires have been investigated using both quantum and classical molecular dynamics simulations to determine the most stable forms. The tetrahedral type nanowires have been found to be the most stable and, surprisingly, the polycrystalline forms of nanowires, while having the smallest surface to bulk ratio, are found to be the least stable. We also show that the cagelike nanowires have greater thermal stability than the tetrahedral nanowires. Furthermore, their electrical conducting properties are found to be better than those of tetrahedral nanowires, suggesting useful molecular electronic applications.     

Quasi-minimality and tightness by range in spaces with unconditional basis

We present a reflexive Banach space with an unconditional basis which is quasi-minimal and tight by range, i.e., of type (4) in the Ferenczi-Rosendal list within the framework of Gowers’ classification program of Banach spaces. The space is an unconditional variant of the Gowers Hereditarily Indecomposable space with an asymptotically unconditional basis.     

Synthesis, thermal analysis, and spectroscopic and structural characterizations of zinc(II) complexes with salicylaldehydes

In this study, three new zinc(II) complexes with 5-substituted salicylaldehyde ligands (X-saloH) (X = 5-chloro, 5-nitro and 5-methyl) with the general formula [Zn(X-salo)₂(CH₃OH)n], (n = 0 or 2) were synthesized. An octahedral geometry was found for both the complexes [Zn(5-NO₂-salo)₂(CH₃OH)₂] and [Zn(5-Cl-salo)₂(CH₃OH)₂] by single-crystal X-ray diffraction analysis. These complexes were characterized also by spectroscopy (IR and ¹H-NMR). Simultaneous TG/DTG–DTA techniques were used to analyze their thermal behavior under inert atmosphere, with particular attention to determine their thermal degradation pathways, which was found to be a multi-step decomposition accompanied by the release of the ligand molecules. Finally, the kinetic analysis of the decomposition processes was performed by applying both the isoconversional Ozawa–Flynn–Wall (OFW) and the Kissinger–Akahira–Sunose (KAS) methods.     

C7‐Indole Amidations and Alkenylations by Ruthenium(II) Catalysis

C7?H‐functionalized indoles are ubiquitous structural units of biological and pharmaceutical compounds for numerous antiviral agents against SARS‐CoV or HIV‐1. Thus, achieving site‐selective functionalizations of the C7?H position of indoles, while discriminating among other bonds, is in high demand. Herein, we disclose site‐selective C7?H activations of indoles by ruthenium(II) biscarboxylate catalysis under mild conditions. Base‐assisted internal electrophilic‐type substitution C?H ruthenation by weak O‐coordination enabled the C7?H functionalization of indoles and offered a broad scope, including C?N and C?C bond formation. The versatile ruthenium‐catalyzed C7?H activations were characterized by gram‐scale syntheses and the traceless removal of the directing group, thus providing easy access to pharmaceutically relevant scaffolds. Detailed mechanistic studies through spectroscopic and spectrometric analyses shed light on the unique nature of the robust ruthenium catalysis for the functionalization of the C7?H position of indoles.     

Novel methodology for 3D reconstruction of carotid arteries and plaque characterization based upon magnetic resonance imaging carotid angiography data

In this study, we present a novel methodology that allows reliable segmentation of the magnetic resonance images (MRIs) for accurate fully automated three-dimensional (3D) reconstruction of the carotid arteries and semiautomated characterization of plaque type. Our approach uses active contours to detect the luminal borders in the time-of-flight images and the outer vessel wall borders in the T(1)-weighted images. The methodology incorporates the connecting components theory for the automated identification of the bifurcation region and a knowledge-based algorithm for the accurate characterization of the plaque components. The proposed segmentation method was validated in randomly selected MRI frames analyzed offline by two expert observers. The interobserver variability of the method for the lumen and outer vessel wall was -1.60%±6.70% and 0.56%±6.28%, respectively, while the Williams Index for all metrics was close to unity. The methodology implemented to identify the composition of the plaque was also validated in 591 images acquired from 24 patients. The obtained Cohen's k was 0.68 (0.60-0.76) for lipid plaques, while the time needed to process an MRI sequence for 3D reconstruction was only 30 s. The obtained results indicate that the proposed methodology allows reliable and automated detection of the luminal and vessel wall borders and fast and accurate characterization of plaque type in carotid MRI sequences. These features render the currently presented methodology a useful tool in the clinical and research arena.     

Simple, accurate formula for the average bit error probability of multiple-input multiple-output free-space optical links over negative exponential turbulence channels

In this Letter we investigate the error performance of multiple-input multiple-output free-space optical communication systems employing intensity modulation/direct detection and operating over strong atmospheric turbulence channels. Atmospheric-induced strong turbulence fading is modeled using the negative exponential distribution. For the considered system, an approximate yet accurate analytical expression for the average bit error probability is derived and an efficient method for its numerical evaluation is proposed. Numerically evaluated and computer simulation results are further provided to demonstrate the validity of the proposed mathematical analysis.     

Anti-Cancer Activity and Phenolic Content of Extracts Derived from Cypriot Carob (Ceratonia siliqua L.) Pods Using Different Solvents

Extracts derived from the Ceratonia siliqua L. (carob) tree have been widely studied for their ability to prevent many diseases mainly due to the presence of polyphenolic compounds. In this study, we explored, for the first time, the anti-cancer properties of Cypriot carobs. We produced extracts from ripe and unripe whole carobs, pulp and seeds using solvents with different polarities. We measured the ability of the extracts to inhibit proliferation and induce apoptosis in cancer and normal immortalized breast cells, using the MTT assay, cell cycle analysis and Western Blotting. The extracts’ total polyphenol content and anti-oxidant action was evaluated using the Folin–Ciocalteu method and the DPPH assay. Finally, we used LC-MS analysis to identify and quantify polyphenols in the most effective extracts. Our results demonstrate that the anti-proliferative capacity of carob extracts varied with the stage of carob maturity and the extraction solvent. The Diethyl-ether and Ethyl acetate extracts derived from the ripe whole fruit had high Myricetin content and also displayed specific activity against cancer cells. Their mechanism of action involved caspase-dependent and independent apoptosis. Our results indicate that extracts from Cypriot carobs may have potential uses in the development of nutritional supplements and pharmaceuticals.