Weak decays of 4He-Lambda

We measured the lifetime and the mesonic and non-mesonic decay rates of the 4He-Lambda hypernucleus. The hypernuclei were created using a 750 MeV/c momentum K- beam on a liquid 4He target by the reaction 4He(K-,pi-)4He-Lambda. The 4He-Lambda lifetime was directly measured using protons from Lambda p -> n p non-mesonic decay (also referred to as proton-stimulated decay) and was found to have a value of tau = 245 +/- 24 ps. The mesonic decay rates were determined from the observed numbers of pi-'s and pi0's as Gamma_pi-/Gamma_tot = 0.270 +/- 0.024 and Gamma_pi0/Gamma_tot = 0.564 +/- 0.036, respectively, and the values of the proton- and neutron-stimulated decay rates were extracted as Gamma_p/Gamma_tot = 0.169 +/- 0.019 and Gamma_n/Gamma_tot <= 0.032 (95% CL), respectively. The effects of final-state interactions and possible 3-body Lambda N N decay contributions were studied in the context of a simple model of nucleon-stimulated decay. Nucleon-nucleon coincidence events were observed and were used in the determination of the non-mesonic branching fractions. The implications of the results of this analysis were considered for the empirical Delta I = 1/2 rule and the decay rates of the 4H-Lambda hypernucleus.Comment: 15 pages, 11 figures, published in PRC, revised content to match published versio

Artocarpin, a Promising Compound as Whitening Agent and Anti-skin Cancer

In our search for natural products from wood on cosmetics and drugs purposes and on the basis of melanin biosynthesis assay guided fractionation, artocarpin was isolated from wood of Nangka (Artocarpus heterophyllus). To evaluate the potency as a whitening agent of artocarpin and its anti-skin cancer (cytotoxicity effect), the MTT assay was used to evaluate its cytotoxicity on cells and melanin biosynthesis assays was performed to determine its whitening agents potency. The evaluation of cytotoxicity on B16 melanoma cells of Artocarpin resulted the IC50 was 10.3 µM and melanin biosynthesis assay with IC50 6.7 µM with out cytotoxicity. Based on the results, suggested that artocarpin have a potent to be developed as whitening agent and skin cancer drug