Most vital segment barriers

We study continuous analogues of "vitality" for discrete network flows/paths, and consider problems related to placing segment barriers that have highest impact on a flow/path in a polygonal domain. This extends the graph-theoretic notion of "most vital arcs" for flows/paths to geometric environments. We give hardness results and efficient algorithms for various versions of the problem, (almost) completely separating hard and polynomially-solvable cases

Comparative analysis of four medicinal floras: phylogenetic methods to identify cross-cultural patterns

Summary Four medicinal floras were compared using phylogenetic methods, to test whether there are shared patterns in medical plant use at the level of the whole medicinal floras, or for specific therapeutic applications. Checklists of the native plants and medicinal plants of Oman were compiled, and analyzed alongside existing checklists for Nepal, the Cape of South Africa and New Zealand. We reconstructed a plant phylogeny at generic level for Oman, and a new, more inclusive phylogeny to represent the genera found in all four local floras. Methods from community phylogenetics were used to identify clustering and overdispersion of the plants used. The impacts of using local or more inclusive phylogenies and different null model selections were explored. We found that Omani medicinal plant use emphasizes the same deep lineages of flowering plants as the other three medicinal floras, most strongly when comparing Omani and Nepalese medicinal plants. Drivers of this similarity might be floristic composition, opportunity for exchange of knowledge and shared beliefs in the causation of illness. Phylogenetic patterns among therapeutic applications are cross‐predictive within and between cultures, and must be interpreted with care since inappropriate use of null models can result in spurious similarity. High levels of cross‐predictivity suggest that targeting plants used for specific therapeutic applications to identify specific bioactives may have limited value. We outline the questions that might be addressed using a global phylogeny and medicinal plant checklists, suggest the best methods for future studies and propose how findings might be interpreted

Antiviral Activity of Some Plants Used in Nepalese Traditional Medicine

Methanolic extracts of 41 plant species belonging to 27 families used in the traditional medicine in Nepal have been investigated for in vitro antiviral activity against Herpes simplex virus type 1 (HSV-1) and influenza virus A by dye uptake assay in the systems HSV-1/Vero cells and influenza virus A/MDCK cells. The extracts of Astilbe rivularis, Bergenia ciliata, Cassiope fastigiata and Thymus linearis showed potent anti-herpes viral activity. The extracts of Allium oreoprasum, Androsace strigilosa, Asparagus filicinus, Astilbe rivularis, Bergenia ciliata and Verbascum thapsus exhibited strong anti-influenza viral activity. Only the extracts of A. rivularis and B. ciliata demonstrated remarkable activity against both viruses

An antiproliferative norditerpene dilactone, Nagilactone C, from Podocarpus neriifolius

An ethanolic extract of Podocarpus neriifolius D. Don (Podocarpaceae) showed antiproliferative activity against two major tumor cell lines, viz. human HT-1080 fibrosarcoma and murine color 26-L5 carcinoma. Bioassay guided fractionation showed the highest antiproliferative activity in chloroform\u2013soluble fraction. Nagilactone C, the major constituent of this fraction was isolated and characterized by using NMR, IR and FAB-MS spectroscopic methods. Nagilactone C possessed potent antiproliferative activity against human fibrosarcoma and murine colon carcinoma tumor cell lines exhibiting ED50 values of 2.3 and 1.2 \u3bcg/ml, respectively. Hence, nagilactone C could be the active constituent present in this plant.Peer reviewed: YesNRC publication: N