Anti-counterfeiting fiber system with near-infrared wavelength selectivity based on photothermal and thermochromic dyes.

Anti-counterfeiting (ACF) technology plays a crucial role in distinguishing genuine products from counterfeits, as well as in identity verification. Moreover, it serves as a protective measure for safeguarding the rights of individuals, companies, and governments. In this study, a high-level ACF technology was developed using a color-conversion system based on the photothermal effect of near-infrared (NIR) wavelengths. Diimonium dye (DID), which is a photothermal dye, was selected because it is an NIR absorbing dye with over 98% transparency in the visible light (vis) region. Due to the photothermal properties of DID, the temperature increased to approximately 65 °C at 1064 nm and 39 °C at 808 nm, respectively. Additionally, we employed a donor-acceptor Stenhouse adduct dye, a thermochromic dye, which exhibits reversible color change due to heat (red color) and light (colorless). Our ACF technology was applied to the brand-protecting fiber utilizing the difference in photothermal temperature according to the NIR wavelength. We successfully implemented anti-counterfeit clothing using alphabet K labels that could distinguish between genuine and counterfeit products by irradiating with specific NIR wavelengths.

Development of radical initiator based on o-imino-isourea capable of photo/thermal polymerization.

Using o-imino isourea, three photo- and thermal dual-responsive radical initiators dicyheDCC, CyheDCC, and BnDCC were systematically developed and synthesized. By adding an aromatic ring to the free radical initiators, the ultraviolet-visible absorption was redshifted, and the absorption coefficient was increased. Compared with other initiators, BnphDCC exhibited an exceptional photoinitiation rate under photo-differential scanning calorimetry (DSC) and a high absorption coefficient (ε = 15 420 M-1 cm-1). Therefore, it is an appropriate potential photoinitiator. DicyheDCC, which was composed of a cyclic hydrocarbon, exhibited rapid thermal initiation (Tpeak = 82 °C) during thermal DSC, making it a valuable thermal radical initiator. Because of the low stiffness of the N-O link in radical initiators, density functional theory predicts that the aliphatic ring has a significantly lower enthalpy than the aromatic ring. Moreover, in this study, CyhephDCC and BnphDCC, as dual-responsive radical initiators, indicated the potential for a photo- and heat dual-curing system through the universal free-radical polymerization of acrylates. These significant discoveries may be useful for developing efficient and diversified polymer network systems that require synergistic photo- and thermal effects.

Transition to an irreversible state of senescence in HeLa cells arrested by repression of HPV E6 and E7 genes.

Inhibition of human papillomavirus (HPV) E6 and E7 transcription by means of the E2 protein of bovine papillomavirus 1 (BPV1) has been shown to induce acute growth arrest in HPV-positive cervical carcinoma cells. This state of arrest is marked by the expression of senescence phenotypes including SA beta-Gal activity and lipofuscin accumulation. In this study, we examined the reversibility of these phenotypes by exogenously expressing the E6 and E7 genes into HeLa cells growth-arrested by the depletion of E6/E7. Re-expression of E7 (but not E6) in 2 days following E2 transduction induced the cells to resume growth. The proliferating cells manifested the phenotype of untreated HeLa cells, suggesting that E7 is the major factor responsible for the continued proliferation and the suppression of the senescence phenotype in cervical carcinoma cells. However, E7 in 5 days following E2 transduction did not prevent HeLa cells from entering the senescent state, indicating that the arrested state becomes irreversible. Our results suggest that, upon depletion of the viral oncoproteins, a senescent state is irreversibly induced in HeLa cells after a period of commitment. The status and cellular location of certain factors involved in signal transduction and cell cycle control was altered as well along with this irreversibility transition.

First characterization of Plasmodium vivax liver stage antigen (PvLSA) using synthetic peptides.

BACKGROUND: Plasmodium vivax is the most widespread human malaria in tropical and subtropical countries, including the Republic of Korea. Vivax malaria is characterized by hypnozoite relapse and long latency infection by the retained liver stage of P. vivax, and somewhat surprisingly, little is known of the liver stage antigens of this parasite. Here, we report for the first time the characterization of a liver stage antigen of P. vivax (PvLSA). METHODS: Five peptides located inside PvLSA were synthesized, and specific anti-sera to the respective peptides were used to localize PvLSA on P. vivax parasites in human liver cells by immunofluorescence. Western blotting and enzyme-linked immunosorbent assay were performed using the five peptides and sera collected from vivax malaria patients and from normal healthy controls. RESULTS: PvLSA was localized on P. vivax parasites in human liver cells. Vivax malaria-infected patients were detected using the five peptides by western blotting. Furthermore, the peptides reacted with the sera of vivax malaria patients. CONCLUSIONS: These results suggest that PvLSA may function during the liver stage of P. vivax.