Optimal strategy of vaccination and treatment in an SIRS model with Markovian switching

Medical treatment and vaccination decisions are often sequential and uncertain. Markov decision process is an appropriate means to model and handle such stochastic dynamic decisions. This paper studies the near‐optimality of a stochastic SIRS epidemic model that incorporates vaccination and saturated treatment with regime switching. The stochastic model takes white noises and color noise into account. We first prove some priori estimates of the susceptible, infected, and recovered populations. Moreover, we establish some sufficient and necessary conditions of the near‐optimality by Pontryagin stochastic maximum principle. Our results show that the two kinds of environmental noises have great impacts on the infectious diseases. Finally, we illustrate our conclusions through numerical simulations.     

Tributyltin(IV) Schiff base complexes with amino acid derivatives: synthesis,characterization and biological activity

The synthesis in one‐pot reactions and structural characterization of six new tri‐n‐butyltin(IV) derivatives of Schiff bases are reported. The compounds are derived from a condensation reaction between l ‐alanine, l ‐valine, l ‐isoleucine, l ‐methionine, l ‐phenylalanine or l ‐tryptophan and 3,5‐di‐tert‐butyl‐2‐hydroxybenzaldehyde. Characterization was completed using elemental analysis, infrared spectroscopy, mass spectrometry, one‐ and two‐dimensional solution NMR (¹H, ¹³C and ¹¹⁹Sn) as well as solid‐state ¹¹⁹Sn NMR. In addition, the crystal structures of three of the compounds were confirmed using single‐crystal X‐ray diffraction. Although five‐coordinated and polymeric in the solid state, the tin compounds are four‐coordinated and monomeric in solution. The coordination environment around the triorganotin units comprises three carbon atoms and two oxygen atoms from two ligands in a trigonal bipyramidal geometry. The anti‐proliferative effect of these compounds on the cervical carcinoma cell lines HeLa, CaSki and ViBo was screened in vitro, the compounds showing cytotoxic activity against all three strains and null or low cytotoxic activity (necrotic) as well. Copyright © 2016 John Wiley & Sons, Ltd.     

On ω-limit Sets of Triangular Maps on the Unit Cube

We consider Sturm–Liouville eigenvalue problems of second order with arbitary seperated boundary conditions and perform a suitabl discretization of them. The obtained discrete Sturm–Liouville eigenvalue problems are examined and the asymptotic behavior of their eigenvalue as the norm of the partition tends to zero is investigated.     

Reactions of aldehyde with collagen: a DFT study

Structural Chemistry - The reaction mechanisms of several amino acids (Asn, Gln, Arg, His, and Lys) in the collagen with aldehyde were studied using density functional theory method. Based on the...     

Addition of Al(OH)3 versus AlO(OH) nanoparticles on the optical,thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

Cellulose - Differently structured aluminum (tri/mono) hydroxide (Al(OH)3 /AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC),...     

Two New 4‐Hydroxyisoflavanes from the Root of Codonopsis cordifolioidea and Their Anti‐virus Activities

Two new 4‐hydroxyisoflavanes, cordifoliflavanes A and B (1 and 2), were isolated from the roots of Codonopsis cordifolioidea. Their structures were elucidated by spectroscopic methods, including extensive 1D‐ and 2D‐NMR techniques. Compounds 1 and 2 were tested for their anti‐HIV‐1 activities and anti‐tobacco mosaic virus activities. The results showed that compounds 1 and 2 have modest anti‐HIV‐1 activities and anti‐tobacco mosaic virus activities, respectively.     

Cytotoxic and NF-κB inhibitory sesquiterpene lactones from Piptocoma rufescens

Six new (1-6) and eight known germacranolide-type sesquiterpene lactones, along with several known phenylpropanol coumarates and methylated flavonoids, were isolated from the leaves of Piptocoma rufescens, collected in the Dominican Republic. The new compounds were identified by analysis of their spectroscopic data, with the molecular structure of 3 being established by single-crystal X-ray diffraction. The absolute configurations of the sesquiterpene lactones isolated were determined from their CD and NOESY NMR spectra, together with the analysis of Mosher ester reactions. Bioassay screening results showed the majority of the sesquiterpene lactones isolated (1-13) to be highly cytotoxic toward the HT-29 human colon cancer cell line, with the most potent compound being 15-deoxygoyazensolide (10, IC(50), 0.26 μM). In addition, several of the sesquiterpene lactones exhibited NF-κB (p65) inhibitory activity.     

Determination of Malathion Using Corona Discharge – Ion Mobility Spectrometry with Solid-Phase Microextraction

A corona discharge (CD) ion mobility spectrometer combined with solid-phase microextraction was constructed. The detection limit and stability of the system for malathion detection were improved using a novel sample introduction port through which the sample desorption was performed in high-temperature drift tube and the sample was introduced directly to the ionization area. The working parameters of the distance between CD needle tip and carrier gas outlet, the drift tube and carrier gas temperature, the carrier gas flow, and the voltage on CD needle were selected. When the extraction time for standard malathion was set to 5?min, the detection limit was 0.96?µg?L^?1 based on thrice the baseline noise, the linear range was 50–500?µg?L^?1, the correlation coefficient was approximately 0.9941, and the relative standard deviation was below 10%. Malathion-spiked lake water samples were analyzed using the developed system and the recovery was 92–102%. This method is suitable for the rapid detection of organophosphorus pesticide residues.