Evaluation of the performance of IND/Zn and DFO on various porous substrates in Singapore context.

Enhancement of latent fingermarks found at crime scenes can be crucial to criminal investigations. The performance of ninhydrin analogues 1,2-indanedione (IND/Zn) and 1,8-diazafluoren-9-one (DFO) used in laboratories for the enhancement of latent fingermarks on porous substrates were compared for operational use. The visualisation of enhanced latent fingermarks on seven substrates commonly encountered in local crimes - plain A4 paper, glossy magazine, paper magazine, brown envelopes, white envelopes, cardboard, and joss paper were assessed using fingermarks deposits from seven donors. Fingermarks were aged under both indoor and outdoor conditions as well as over different periods of time. Our results show that IND/Zn consistently produced fingermarks of superior quality and contrast to DFO across the different donors, substrates and time periods. IND/Zn also appears to be more sensitive compared to DFO.

Effect of HIF-1α on biological activation of human tongue squamous cell carcinoma SCC-15 cells in vitro.

Hypoxia-inducible factor-1α (HIF-1α) is a key regulator for tumor cells and tissues to adapt to hypoxic condition. Suppressing the expression of HIF-1α is important to evaluate its effect on cancer cells. This study was carried out to analyze the effect of HIF-1α on the biological activation of human tongue squamous cell carcinoma (TSCC) SCC-15 cells. In this experiment, deferoxamine mesylate (DFO) was used to induce hypoxic condition. HIF-1α gene was suppressed by lentiviral vector. The effect of the level of HIF-1α expression was tested on the proliferation, cell cycle, cell apoptosis and cell invasion of SCC-15 cells. We demonstrated that SCC-15 cells showed a more aggressive phenotype after treated with DFO. Additionally, DFO was able to induce the expression of HIF-1α protein. Lentiviral vector can effectively inhibit HIF-1α expression on mRNA and protein level. Under normoxic or hypoxic conditions, downregulation of HIF-1α for SCC-15 cells induced cell apoptosis and inhibited growth and invasion. These results showed that suppressing the expression of HIF-1α inhibited the aggressive potential of SCC-15 cells under normoxic and hypoxic condition. Thus, finding an effective and safe pathway to inhibit the expression of HIF-1α can help us to improve the survival rate of human TSCC patients.

Primary-Colored Electrochromism of 1,4-Phenylenediamines.

Ten 1,4-phenylenediamines were studied using electrochemical techniques (voltammetry and controlled potential electrolysis) and UV/Vis spectroscopy under ambient conditions. All compounds demonstrated vibrant color changes upon one-electron electrochemical oxidation in acetonitrile, with most displaying a primary color (red, green, blue, or yellow) in their oxidized state. The four electrochromes that exhibited the most intense color changes were examined by using a gold micromesh electrode laminated inside a polymer film to determine their electrochromic properties in solution (contrast ratios, chromatic efficiency, and cycle life). Their colored radical cations were also characterized by electron paramagnetic resonance spectroscopy as well as monitored for color retention over a period of 24 hours. Notably, only relatively small potentials were required to initiate the chromatic changes and the oxidized forms of the compounds were long-lived and unaffected by atmospheric oxygen or moisture.