We previously isolated a novel natural product, designated kohamaic acid A (KA-A, compound 1), as an inhibitor of the first cleavage of fertilized sea urchin eggs, and found that this compound could selectively inhibit the activities of mammalian DNA polymerases (pols). In this paper, we investigated the structure and bioactivity of KA-A and its chemically synthesized 11 derivatives (i.e., comp...

The aging process causes a number of changes in the skin, including oxidative stress and dyschromia. The kojic acid (KA) is iron chelator employed in treatment of skin aging, and inhibits tyrosinase, promotes depigmentation. Nanotechnology-based drug delivery systems, such as liquid crystalline systems (LCSs), can modulate drug permeation through the skin and improve the drug activity. This stu...

BACKGROUND Although intralesional methotrexate (MTX) is an effective, nonsurgical treatment of keratoacanthoma (KA), there have not been many reports of on the MTX treatment for KA in Korea. OBJECTIVE The purpose of this study was to evaluate the clinical efficacy of the intralesional MTX for the treatment of KA in Korean patients. METHODS We retrospectively studied seven patients with KA w...

A 12.4 m core taken in Lake Bangong provides a continuous Holocene climatic record. We summarize information on changes in stable isotope and radiocarbon balances in the lake, hydrobiology and vegetal cover in the catchment, deduced from detailed analytical results given in the three preceding papers. The Bangong record is then compared with the environmental history of the neighbouring Lake Su...

Previous epilepsy-related gene screen identified a spontaneous recurrent seizure (SRS)-related gene named epilepsy-related gene (ERG1) that encodes N-ethylmaleimide-sensitive fusion protein (NSF). To explore whether spatial learning memory deficits are relevant to SRS and whether hippocampal NSF expression is altered by SRS, we used the kainic acid (KA)-induced epilepsy animal model. SRS was mo...

Two natural products Polypodium leucotomos extract (PL) and kojic acid (KA) were tested for their ability to scavenge reactive oxygen species (.OH,.O2-, H2O2, 1O2) in phosphate buffer. Hydroxyl radicals were generated by the Fenton reaction, and the rate constants of scavenging were 1.6 x 10(9) M-1 s-1 for KA and 1.0 x 10(9) M-1 s-1 for PL, similar to that of ethanol (1.4 x 10(9) M-1 s-1). With...

Geophysical and sedimentary records from five lakes in Massachusetts reveal regionally coherent hydrologic variability during the Holocene. All of the lakes have risen since ~9.0 ka, but multicentury droughts after 5.6 ka repeatedly lowered their water levels. Quantified water level histories from the three best-studied lakes share >70% of their reconstructed variance. Four prominent low-water ...

The Knowledge Annotation Initiative of the Knowledge Acquisition Community, (KA) 2 is an initiative to develop an ontology that models the knowledge acquisition community (its researchers, topics , products, etc.). This ontology will form the basis to annotate WWW documents of the KA community in order to enable intelligent access to these documents. (KA) 2 is an open joint-initiative where the...

Non-linear saturation kinetics can be described through a potency function, a trigonometric function, a logarithmic function, a hyperbolic function, or an exponential function. Saturable enzyme reaction kinetics can be alternatively formulated as a 1-exp function without the limitations of a steady-state assumption (d[C]/dt = 0, where C is the enzyme-substrate complex). The time-dependent subst...

The Constrained Bipartite Vertex Cover problem asks, for a bipartite graph G with partite sets A and B, and integers kA and kB , whether there is a vertex cover for G containing at most kA vertices from A and kB vertices from B. The problem has an easy kernel with 2kA · kB edges and 4kA · kB vertices, based on the fact that every vertex in A of degree more than kB has to be included in the solu...