Supplier-customer interaction in quality control

We develop a game theoretic model of joint quality control in a single sourcing environment which integrates supplier and customer decisions. In this model, both parties behave strategically and take each other's incentives into account when deciding on their respective sampling plans. The specific sampling plans considered are of the single sample fraction defective with rectifying inspection type. A method to find the optimal sampling plans for both supplier and customer in two different informational setups is constructed. The resulting models lead to examination of Stackelberg and Nash equilibria. Numerical examples of such equilibria are presented, indicating how optimal strategies depend on the parameters of the problem.     

An application of the mannich reaction using hydroxylamine and some of its derivatives. 6-Substituted-2,4-diamino-5,6,7,8-tetrahydropyrimido[4,5-dpyrimidines

Hydroxylamine and some of its O -substituted derivatives ( 2 ) have been used as the amine component in Mannich reactions with 2,4,6-triaminopyrimidine ( 1 ). The resulting 6-substituted tetrahydropyrimido[4,5-d]-pyrimidines ( 3 ) contain an N-0 bond linking the substituent to the ring. These results extend the utility of this modified Mannich reaction to otherwise inaccessible substituents. Reaction conditions, spectral data and certain limitations of the reaction are discussed.     

Fabrication of three-dimensional photonic crystals with tunable photonic properties by biotemplating

Photonic crystals with tunable D-surface structures for possible high-temperature gas- and temperature-sensing applications were prepared by a biotemplating method. This included infiltrating colored scales of the beetle Entimus imperialis with an organopolysiloxane mixture followed by simultaneous combustion of the template and calcination of the cured organopolysiloxane. A high-yield inorganic silica-based replica of the original structure was obtained, which is capable of withstanding temperatures up to 600 °C. Light- and scanning electron microscopy combined with focused ion beam milling showed a precise replication of the whole scales and their internal D-surface structure. Fourier-transform infrared spectroscopy and X-ray diffraction analysis confirmed the complete curing of the organopolysiloxanes and their transformation into amorphous silica during calcination. The dielectric constant of the manufactured materials determined by Abbé refractometry was ? = 2.3180 and used to perform band structure calculations utilizing the plane wave expansion method. By changing the chain length and degree of crosslinking of the organopolysiloxane precursor mixture, the lattice parameters and filling factors, and therefore the photonic properties of the replicas, could be tuned.     

Syntheses of methylpyridine and methylpyridine N-oxide decorated benzoxazine and naphthoxazine platforms

Simple, aqueous-based syntheses of methylpyridine and methylpyridine N-oxide decorated 3,4-dihydro-2H-naphthoxazine and 2,3-dihydro-1H-naphthoxazine monomers, as well as thermally promoted syntheses of 3,4-dihydro-2H-benzoxazine monomers and bisoxazine methylpyridine derivatives of substituted 1,5-, 2,6-, and 2,7-dihydroxynaphthalenes are described. The crystal structures of two derivatives are presented.     

Anti‐Pasch optimal packings with triples

It is shown that for , there exists an optimal packing with triples on points that contains no Pasch configurations. Furthermore, for all (mod 6), there exists a pairwise balanced design of order , whose blocks are all triples apart from a single quintuple, and that has no Pasch configurations amongst its triples.     

In situ Synthesis of Oligonucleotide Arrays on Surfaces Coated with Crosslinked Polymer Multilayers

We report an approach to the in situ synthesis of oligonucleotide arrays on surfaces coated with crosslinked polymer multilayers. Our approach makes use of methods for the 'reactive' layer-by-layer assembly of thin, amine-reactive multilayers using branched polyethyleneimine (PEI) and the azlactone-functionalized polymer poly(2-vinyl-4,4'-dimethylazlactone) (PVDMA). Post-fabrication treatment of film-coated glass substrates with d-glucamine or 4-amino-1-butanol yielded hydroxyl-functionalized films suitable for the Maskless Array Synthesis (MAS) of oligonucleotide arrays. Glucamine-functionalized films yielded arrays of oligonucleotides with fluorescence intensities and signal-to-noise ratios (after hybridization with fluorescently labeled complementary strands) comparable to those of arrays fabricated on conventional silanized glass substrates. These arrays could be exposed to multiple hybridization-dehybridization cycles with only moderate loss of hybridization density. The versatility of the layer-by-layer approach also permitted synthesis directly on thin sheets of film-coated poly(ethylene terephthalate) (PET) to yield flexible oligonucleotide arrays that could be readily manipulated (e.g., bent) and cut into smaller arrays. To our knowledge, this work presents the first use of polymer multilayers as a substrate for the multi-step synthesis of complex molecules. Our results demonstrate that these films are robust and able to withstand the ~450 individual chemical processing steps associated with MAS (as well as manipulations required to hybridize, image, and dehybridize the arrays) without large-scale cracking, peeling, or delamination of the thin films. The combination of layer-by-layer assembly and MAS provides a means of fabricating functional oligonucleotide arrays on a range of different materials and substrates. This approach may also prove useful for the fabrication of supports for the solid-phase synthesis and screening of other macromolecular or small-molecule agents.     

The effect of cooking and washing rice on the bio-accessibility of As,Cu, Fe,V and Zn using an on-line continuous leaching method

A previously developed method based on continuous on-line leaching with artificial gastro-intestinal fluids was used to determine the bio-accessible fraction of As, Cu, Fe, V and Zn in brown and white rice from California by inductively coupled mass spectrometry (ICP-MS). Saliva generally accounted for the largest percentage of total element leached in comparison to gastric and intestinal juices. Arsenic speciation analysis was performed on the saliva and gastric juice leachates using ion exchange chromatography coupled to ICP-MS. The four most toxic species of As (As(III), monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and As(V)), as well as Cl⁻ in the gastric juice leachate, were successfully separated within 5.5 min using a simple nitric acid gradient. While cooking rice had relatively little effect on total bio-accessibility, a change in species from As(V) and DMA to As(III) was observed for both types of rice. On the other hand, washing the rice with doubly deionized water prior to cooking removed a large percentage of the total bio-accessible fraction of As, Cu, Fe, V and Zn.     

Ion exchange chromatography coupled to inductively coupled plasma mass spectrometry for the study of Pt electro-dissolution

There is an ongoing debate regarding the mechanism of Pt electrochemical dissolution. However, only off-line methods have so far been used, where separation of Pt species is performed separately from their detection. In this study, ion exchange chromatography coupled to inductively coupled plasma mass spectrometry was used for the first time to separate and detect Pt species generated by the electro-dissolution of a Pt electrode in 0.5 M aqueous H₂SO₄ solution. Because these species are either neutral or cationic, they were converted to chloro-complexes using 0.1 M KCl to enable their separation by anion exchange chromatography. Chloro-aqua complexes were observed in addition to the two predominant species, namely PtCl₄²⁻ and PtCl₆²⁻. A good linear relationship was observed between the sum of peak areas for all complexes of a given Pt oxidation state and the Pt concentration, with a detection limit of 0.1 μg L⁻¹ being reached for Pt(II) and Pt(IV). Application of this speciation analysis method to real samples generated by potential cycling using cyclic voltammetry (CV) revealed that, in general, at least 80% of Pt was present as Pt(II), irrespectively of the cyclic potential range or of temperature (up to 60 °C). Still, quantitative spike recovery was achieved after adding known amounts of Pt(II) or Pt(IV) to a sample prepared by CV, which demonstrated that no significant species inter-conversion took place.     

Sultam Thioureas Synthesized via an Alternative Ring-Forming Reaction

A method for the synthesis of sultam thioureas via a different 1,4,2-dithiazolidine 1,1-dioxide ring-forming reaction is presented here. The syntheses of nine sultam thioureas were achieved in 53–81% yield by reacting N-substituted chloromethanesulfonamides with thiocarbamoyl isothiocyanates, which were formed in situ from the reaction of 5-(disubstituted amino)-3H-1,2,4-dithiazole-3-thiones with triphenylphosphine. Importantly, this method successfully allowed the substituent of the ring nitrogen atom to be varied. Additionally, the structures of four sultam thioureas were confirmed by x-ray diffraction.