Global dynamics of an epidemiological model with age-of-infection dependent treatment rate

We revisit a previously established model for influenza transmission dynamics, in which antiviral treatment as a single containment strategy was administered within a specified window of opportunity for initiating treatment. We extend this model to a more general framework with age-of-infection dependent treatment rates. The resulting age structured model can be transformed into a closed system of delay differential equations, for which we perform a complete global stability analysis. By constructing suitable Lyapunov functions, we show that the effective reproduction number fully characterizes the possible outcomes of disease dynamics. Our results allow us to evaluate treatment strategies and examine the impact of treatment delays on the potential success of disease control.     

NIR Mega‐Stokes Fluorophores for Bioorthogonal Labeling and Energy Transfer Systems–An Efficient Quencher for Daunomycin

A set of new azide‐ and alkyne‐bearing lepidinium‐based fluorophores were synthesized for bioorthogonal labeling schemes. These fluorescent dyes all show large Stokes‐shifts with emission maxima in the near‐infrared (NIR) region of the electromagnetic spectrum. The applicability of these dyes in the construction of energy‐transfer systems was tested using one of these new fluorescent tags and daunomycin (Dau), an anticancer drug with fluorescent features. These daunomycin conjugates are the very first examples of fluorescently modulated constructs of this anticancer agent. The dually labeled architectures proved that the applied fluorescent dye can be utilized as an efficient quencher for daunomycin. Enzymatic cleavage of a dually labeled enzyme substrate resulted in full recovery of the fluorescence of daunomycin. Such fluorescently modulated Dau conjugates can provide useful information for the mechanism of action of Dau‐regulated cell death processes.     

A validated method for measurement of serum total,serum free,and salivary cortisol,using high-performance liquid chromatography coupled with high-resolutionESI-TOF mass spectrometry

Blood cortisol level is routinely analysed in laboratory medicine, but the immunoassays in widespread use have the disadvantage of cross-reactivity with some commonly used steroid drugs. Mass spectrometry has become a method of increasing importance for cortisol estimation. However, current methods do not offer the option of accurate mass identification. Our objective was to develop a mass spectrometry method to analyse salivary, serum total, and serum free cortisol via accurate mass identification. The analysis was performed on a Bruker micrOTOF high-resolution mass spectrometer. Sample preparation involved protein precipitation, serum ultrafiltration, and solid-phase extraction. Limit of quantification was 12.5 nmol L^?1 for total cortisol, 440 pmol L^?1 for serum ultrafiltrate, and 600 pmol L^?1 for saliva. Average intra-assay variation was 4.7 %, and inter-assay variation was 6.6 %. Mass accuracy was <2.5 ppm. Serum total cortisol levels were in the range 35.6–1088 nmol L^?1, and serum free cortisol levels were in the range 0.5–12.4 nmol L^?1. Salivary cortisol levels were in the range 0.7–10.4 nmol L^?1. Mass accuracy was equal to or below 2.5 ppm, resulting in a mass error less than 1 mDa and thus providing high specificity. We did not observe any interference with routinely used steroidal drugs. The method is capable of specific cortisol quantification in different matrices on the basis of accurate mass identification.     

Partitions with certain intersection properties

Partitions of the n ‐element set are considered. A family of m such partitions is called an ( n, m, k )‐pamily, if there are two classes for any pair of partitions whose intersection has at least k elements, and any pair of elements is in the same class for at most two partitions. Let f ( n, k ) denote the maximum of m for which an ( n, m, k )‐pamily exist. A constructive lower bound is given for f ( n, k ), which is compared with the trivial upper bound. Copyright © 2011 Wiley Periodicals, Inc. J Combin Designs 19:345‐354, 2011     

Aminothiazoles and aminothiadiazoles as nucleophiles in aminocarbonylation of iodobenzene derivatives

Various 2-, 3- and 4-substituted iodobenzenes were aminocarbonylated using aminothiazole and aminothiadiazole derivatives in palladium-catalysed reaction. The reaction is chemospecific toward the corresponding carboxamides. Consequently, the application of the above N-nucleophiles provided the N-1,3-thiazol-2-yl- and N-1,3,4-thiadiazol-2-ylcarboxamides in moderate to high yields. Due to the facile work-up of the reaction mixture isolated yields of 90% or higher were obtained in most cases.     

Comparison of quantitative performance of three fluorescence labels in CE/LIF analysis of aspartate and glutamate in brain microdialysate

Three different fluorescent tags have been compared for the quantitative analysis of aspartate and glutamate in brain microdialysate samples. Separation conditions have been optimized to achieve short analysis time using reversed polarity separation in coated capillary. Method validation has revealed similar quantification limit of 0.1?μM of analytes using either of the labels, although LOD values were different: 7.8-9.8?nM for 4-fluoro-7-nitro-2,1,3-benzoxadiazole, 3.5?nM for fluorescein-5-isothiocyanate and 1.3-1.5?nM for carboxyfluorescein succinimidyl ester derivatives. The almost two orders of magnitude difference between LOD and LOQ values is likely due to the unreliable derivatization reaction at low sample concentration. Based on the superior stability, FITC derivatization was used for the analysis of biological samples. The applicability of the method has been demonstrated by analyzing basal and potassium evoked amino acid concentrations in individual brain microdialysate samples.     

Radiation induced degradation of pharmaceutical residues in water: Chloramphenicol

The γ-radiolytic degradation of chloramphenicol (CPL) was investigated in 0.1–1 mmol dm^?3 aqueous solutions at various radiation conditions. The destruction of CPL was monitored by UV–vis spectrophotometric method through the decrease in the intensity of the absorbance band at 276 nm. LC-MS/MS was used to identify the degradation products. Results indicate that ^?OH can add onto the CPL aromatic ring or can abstract H-atom from the side chain. The reductive dechlorination of CPL was also studied based on the reaction of e_aq^? with CPL. In 0.1 mmol dm^?3 solution above 2.5 kGy dose complete CPL degradation was achieved. In the presence of dissolved oxygen at relatively low dose, various oxidation products were observed. In the presence of tertiary butanol radical scavenger tertiary butanol group containing products were also detected. The toxicity increased as a function of dose to 1.0 kGy. At doses higher than 1.0 kGy the toxicity decreased continuously due to further degradation. It was also demonstrated that the O₂^??/HO₂^? pair has low reactivity in CPL solution.