A microarray enzyme-linked immunosorbent assay for autoimmune diagnostics

In order to quantify autoantibodies in the sera of patients with autoimmune disease, we have created a microarray-based immunoassay that allows the simultaneous analysis of 18 known autoantigens. The microarrays contain serial dilutions of the various antigens, thereby allowing accurate determination of autoantibody titer using minimal amounts of serum. The assay is very sensitive and highly specific: as little as 40 fg of a known protein standard can be detected with little or no cross-reactivity to nonspecific proteins. The signal intensities observed from serial dilutions of immobilized antigen correlate well with serial dilutions of autoimmune sera. Miniaturized and highly parallelized immunoassays like these will reduce costs by decreasing reagent consumption and improve efficiency by greatly increasing the number of assays that can be performed with a single serum sample. This system will significantly facilitate and accelerate the diagnostics of autoimmune diseases and can be adapted easily to any other kind of immunoassay.     

Nucleophilic substitution reaction of benzyl benzenesulfonates with anilines in MeOH-MeCN mixtures-I : Effects of substituent and solvent on the transition-state structure

Kinetic studies on nucleophilic substitution reaction of benzyl tosylates with anilines are reported. The reaction was found to proceed via a dissociative S_N2 mechanism with less than 50 % bond formation and extensive bond breaking at the transition state. It was found that positive charge development at the benzylic carbon is substantial and para-substituent effect on the substrate is predominantly of resonance type. Bond formation is shown to be favored by a better nucleophile, by an electron withdrawing group on the substrate and by the more polar(higher MeCN content) solvent. The substrate, nucleophile and solvent were found to follow the RSP.     

N-heterocyclic carbene-catalyzed generation of homoenolates: gamma-butyrolactones by direct annulations of enals and aldehydes

N-Heterocyclic carbenes, prepared in situ from diarylimidazolium salts, serve as highly effective catalysts for the generation of reactive homoenolates from alpha,beta-unsaturated aldehydes. The catalyst-bound homoenolate reacts with electrophilic aldehydes leading, via the key intermediacy of an activated carboxylate, to gamma-butyrolactones in good yields and stereoselectivities. Importantly, this process demonstrates an unprecedented reaction mode for the generation of nucleophilic carbanions with a multifunctional organocatalyst under exceptionally mild and convenient reaction conditions.     

9-Hydroxypheophorbide alpha-induced apoptotic death of MCF-7 breast cancer cells is mediated by c-Jun N-terminal kinase activation

Recently, we synthesized 9-hydroxypheophorbide alpha (9-HPbD), a new chlorophyll-derived photosensitizer. The photo-treatment of MCF-7 human breast cancer cells with 20 kJ/m2 of red light after 5 microM 9-HPbD pretreatment induced cell death, showed typical apoptotic features, i.e., chromatin condensation, phosphatidyl serine externalization, membrane blebbing, and apoptotic bodies with an intact plasma membrane structure. To elucidate the mechanism of 9-HPbD-induced apoptosis, various mediators of the apoptosis were investigated. Release of cytochrome c from mitochondria into the cytosol was distinct 9 h after irradiation, while the levels of most apoptosis-related molecules such as Fas, FasL, Bcl-2, Bax and p53 were unchanged. Furthermore, caspase-9 activated by released cytochrome c was not significantly activated after 9-HPbD-photosensitization. On the other hand, stress-activated protein kinases such as p38 and c-Jun N-terminal kinase (JNK) were activated 1 h after irradiation. Blocking of JNK signaling by transfecting with the dominant negative from of the JNK gene significantly reduced 9-HPbD-induced cell death. Our data show that photosensitization with the new photosensitizer 9-HPbD could induce the apoptotic death of MCF-7 breast cancer cell and that this death is mediated by stress-activated signal through JNK.     

Liquid crystal alignment properties of n-alkylsulphonylmethyl-substituted polyoxyethylenes

The liquid crystal (LC) alignment properties of LC cells fabricated with films of n-alkylsulphonylmethyl-substituted polyoxyethylenes (#S-PEO, #?=?4, 6, 7, 8 and 10), where # is the number of carbon atoms in the n-alkyl side groups having different n-alkyl chain length, were investigated as a function of the rubbing density. The LC cells made from unrubbed #S-PEO (# ≥8) films having more than eight carbon atoms in the n-alkyl side groups showed homeotropic LC alignment. The homeotropic LC alignment behaviour correlated well with the surface energy values of the unrubbed #S-PEO films; homeotropic LC alignment was observed when the surface energy values of the unrubbed #S-PEO films were smaller than about 21.62 mJ m^?2. The LC cells made from rubbed #S-PEO (# ≥7) films having more than seven carbon atoms with a rubbing density of 150 showed homeotropic LC alignment. It was also found that the tilt angle of the LCs on the rubbed #S-PEO films was affected not only by the n-alkyl chain length of the polymers, but also by the rubbing density, regardless of the surface energy value of the #S-PEO film.     

Plasma synthesis of nanosized W–Co composite powder followed by carburization with a methane–hydrogen mixture

Nanosized tungsten carbide and cobalt composite powder was synthesized by a two-step reaction via a thermal plasma process. Ammonium paratungstate (APT) and cobalt oxide were used as the precursors. The injected precursors were vaporized in the plasma flame and the subsequent reduction of the vaporized precursors produced uniformly mixed nanosized tungsten and cobalt composite powder. The subsequent carburization of this powder by CH₄–H₂ mixture resulted in the formation of nanosized WC–Co composite powder with a particle size <110 nm. This new method represents an alternative route that avoids the post-treatment required for the WC_1?x produced when methane was used for direct carburization in the powder production step.     

Some Theorems on the Rogers-Ramanujan Continued Fraction in Ramanujan's Lost Notebook

In his first two letters to G. H. Hardy and in his notebooks, Ramanujan recorded many theorems about the Rogers-Ramanujan continued fraction. In his lost notebook, he offered several further assertions. The purpose of this paper is to provide proofs for many of the claims about the Rogers-Ramanujan and generalized Rogers-Ramanujan continued fractions found in the lost notebook. These theorems involve, among other things, modular equations, transformations, zeros, and class invariants.     

Stress test for a technology credit guarantee fund based on survival analysis

A technology credit guarantee policy has been established to provide financial support to technology-based SMEs with a limited asset base. For an effective technology credit guarantee policy, risk management is essential. In this paper, we investigate a survival model that predicts start-up SMEs’ loan default probability at a given time based on technology attributes along with the economic environment and the firm’s characteristics at the time of the technology credit guarantee fund application. This, in turn, is used for the estimation of the technology fund risk along with a stress test. Our work is expected to contribute to reducing the risks associated with technology financing.