Development of a microfluidic paper-based analytical device for the determination of salivary aldehydes

A low cost, disposable and easy to use microfluidic paper-based analytical device (μPAD) was developed for simple and non-invasive determination of total aldehydes in saliva with a potential to be used in epidemiological studies to assess oral cancer risk. The μPAD is based on the colour reaction between aldehydes (e.g. acetaldehyde, formaldehyde), 3-methyl-2-benzothiazolinone hydrazone (MBTH) and iron(III) to form an intense blue coloured formazan dye. The newly developed μPAD has a 3D design with two overlapping paper layers. The first layer comprises 15 circular detection zones (8 mm in diameter), each impregnated with 8 μL of MBTH, while the second layer contains 15 reagent zones (4 mm in diameter). Two μL of iron(III) chloride are added to each one of the second layer zones after the addition of sample to the detection zones in the first layer. All hydrophilic zones of the μPAD are defined by wax printing using a commercial wax printer.     

Dissolution Behavior and Varied Mesoporosity of Zeolites by NH4F Etching

The mesopores formation in zeolite crystals has long been considered to occur through the stochastic hydrolysis and removal of framework atoms. Here, we investigate the NH₄F etching of representative small, medium, and large pore zeolites and show that the zeolite dissolution behavior, therefore the mesopore formation probability, is dominated by zeolite architecture at both nano- and sub-nano scales. At the nano-scale, the hidden mosaics of zeolite structure predetermine the spatio-temporal dissolution of the framework, hence the size, shape, location, and orientation of the mesopores. At the sub-nano scale, the intrinsic micropore size and connectivity jointly determine the diffusivity of reactant and dissolved products. As a result, the dissolution propensity varies from removing small framework fragments to consuming nanodomains and up to full digestion of the outmost part of zeolite crystals. The new knowledge will lead to new understanding of zeolite dissolution behavior and new adapted strategies for tailoring hierarchical zeolites.     

Novel codeinone derivatives via Michael addition of barbituric acids

Two novel adducts of codeinone with barbituric and 2-thiobarbituric acids have been synthesized via Michael addition. The compounds were spectroscopically elucidated by means of IR-LD spectroscopy of oriented samples as a suspension in nematic liquid crystals, UV spectroscopy and ¹H and ¹³C NMR spectroscopy. The 2-thiobarbituric adduct was characterized by X-ray crystallography. HPLC tandem mass spectrometry (HPLC ESI MS/MS) and thermal methods were also employed. Quantum chemical calculations have been performed with a view to obtaining the electronic structure and vibrational properties of the novel compounds.     

Meson production in p + d reactions

Total and differential cross sections for the reactions p + d → ³He + m ⁰ with m=π, η and p + d → ³H+π⁺ were measured with the GEM detector at COSY for beam momenta between threshold and the maximum of the corresponding baryon resonance. For both reactions a strong forward-backward asymmetry was found. The data were compared with model calculations. The aspect of isospin symmetry breaking is studied. Representing the GEM Collaboration     

Crystal structure and linear-dichroic infrared (IR-LD) spectral analysis of N,N′-diethyl-4-vinylbenzamidinium squarate

The synthesis and crystal structure of N,N′-diethyl-4-vinylbenzamidinium squarate (I) (C₁₅H₁₉N₂O₂) are reported. The squarate dianion (Sq^2?) and (E,Z)-configured amidinium groups are linked through two intermolecular N···O hydrogen bonds with distances of 2.725 Å for E and 2.731 Å for the Z configurated amidinium parts, thus forming an infinite three-dimensional network. The torsion angle between phenylene ring and amidinium group is 66.1(2)° and the analogous one between the first fragment and the vinyl group 9.6(8)°. The IR-characteristic band assignment both in solution and in solid state has been carried out by means of non- and linear polarized IR- spectral analysis.     

Random sums of exchangeable variables and actuarial applications

In this paper we study the accumulated claim in some fixed time period, skipping the classical assumption of mutual independence between the variables involved. Two basic models are considered: Model 1 assumes that any pair of claims are equally correlated which means that the corresponding square-integrable sequence is exchangeable one. Model 2 states that the correlations between the adjacent claims are the same. Recurrence and explicit expressions for the joint probability generating function are derived and the impact of the dependence parameter (correlation coefficient) in both models is examined. The Markov binomial distribution is obtained as a particular case under assumptions of Model 2.