The accuracy of the widely-used two-dimensional hydrodynamic numerical model depends on the quality of the river terrain model, particularly in the main channel. However, in most cases, the bathymetry of the river channel is difficult or expensive to obtain in the field, and there is a lack of available data to describe the geometry of the river channel. We introduce a method that originates from the grid generation with the elliptic equation to generate streamlines of the river channel. The streamlines are numerically solved with the Laplace equations. In the process, streamlines in the physical domain are first computed in a computational domain, and then transformed back to the physical domain. The interpolated streamlines are integrated with the surrounding topography to reconstruct the entire river terrain model. The approach was applied to a meandering reach in the Qinhe River, which is a tributary in the middle of the Yellow River, China. Cross-sectional validation and the two-dimensional shallow-water equations are used to test the performance of the river terrain generated. The results show that the approach can reconstruct the river terrain using the data from measured cross-sections. Furthermore, the created river terrain can maintain a geometrical shape consistent with the measurements, while generating a smooth main channel. Finally, several limitations and opportunities for future research are discussed.

A series of novel amino acid and peptide derivatives of bleomycin (BLM) A(5) were synthesized. All the compounds possessed significant antitumor activities in vitro against HL-60, BGC-823, PC-3MIE8, and MDA-MB-435 cell lines. Their antitumor activities against MDA-MB-435 were 10-fold higher than BLM A5. The DNA cleavage studies indicated that the hydrophobic amino acid or peptide derivatives of BLM A5 could induce higher cleavage ratio of double to single strand DNA than BLM A5. From the DNA binding studies, we found that the derivatives containing either D-conformation amino acid or basic amino acid could facilitate DNA binding of BLM.

The novel analogues 11-16 of bleomycin A(6) (3) were obtained by selective protection of the primary-amine function of the beta-aminoalaninamide moiety of 3 by means of coordination with Cu-II ions, condensation with an aliphatic or aromatic acid R'COOH in the presence of dicyclohexylcarbodiimide, and demetalization (Scheme). The antitumor activity against HeLa and BGC-823 in vitro, binding property with CT-DNA, and cleavage potency towards pBR322 DNA were also studied (Tables 1-3). All the compounds 11-16 displayed significant antitumor activity, which was enhanced as the hydrophobicity of the C-terminus substituent R' increased. but decreased as the DNA-binding affinity increased. There was a negative relationship between DNA-cleavage potency and binding affinity to DNA in this series of compounds.

Replication of HIV-1 requires specific interactions of Tat protein with TAR RNA. Disruption of Tat–TAR RNA interaction could inhibit HIV-1 replication. Here four target compounds were designed and synthesized to bind to TAR RNA for blocking the interaction of Tat–TAR RNA. The core molecule 6,6′-diamino-6,6′-dideoxy-α,α-trehalose was obtained from selective bromination of, α,α-trehalose at C-6,6′, followed by acetylation, azide displacement, deacetylation, and reduction. Coupling of the core molecule with the protected amino acid, then deprotection and guanidinylation generated the novel α,α-trehalose derivatives. Their abilities to inhibit Tat–TAR RNA interaction in human cells were determined by a Tat-dependent HIV-1 LTR-driven CAT assays.

A series of bleomycin analogues was prepared with a facile synthetic method. All the compounds were shown to display significant antitumor activity against HeLa and BGC-823 cell lines in vitro. The binding properties with CT-DNA and cleavage efficiency to pBR322 DNA were investigated, the results indicate that there is a positive relationship between DNA cleavage efficiency and the binding affinity to DNA, and the antitumor activity of the bleomycin analogues is enhanced as the hydrophobicity of the C-terminus substituent side chain increased.

Replication of human immunodeficiency virus type 1 (HIV-1) requires specific interactions of the Tat protein with the transactivation responsive region (TAR) RNA. Tat-TAR RNA Interaction is mediated by a short arginine-rich domain of the protein. Disruption of this interaction could, in theory, create a state of complete viral latency. Here, four novel 6-amino-6-deoxytrehalose guanidinoglycoside derivatives (10 and 13–15) as target molecules have been designed to bind to TAR RNA for blocking the interaction of Tat-TAR RNA. They were obtained by coupling 6-amino-6-deoxy-α,α-trehalose (6) with the protected amino acids, deprotection by catalytic hydrogenation, followed by guanidinylated with S-methylisothiourea sulfate. Their abilities to inhibit Tat-TAR RNA interaction were determined by a Tat-dependent HIV-1 long terminal repeats (LTR)-driven chloramphenicol acetyltransferase (CAT) assays.

A new Mn(II) complex with the planar ligand 6,7-dicycanodipyrido[2,2-D:2',3'-f]quinoxaline (L) [MnL(NO(3))(H(2)O)(3)]NO(3).CH(3)OH (1) has been synthesized and characterized by elemental analysis, IR, TG-DTA and molar conductance. Its crystal structure was determined by X-ray diffraction, crystal data: yellow, triclinic, space group P1;, Z=2, a=7.3743(8) A, b=11.2487(15) A, c=14.1655(15) A, alpha=79.412(2) degrees, beta=83.208(2) degrees, gamma=80.466(2) degrees. The Mn atom was hexa-coordinated to form a distorted octahedral geometry by two nitrogen atoms of L and four oxygen atoms of three H(2)O and NO(3)(-) in the complex. The binding mode of the complex with calf thymus DNA has also been investigated with spectrophotometric methods, viscosity and thermal denaturation measurements. The experimental results indicate that the complex intercalated into DNA base pairs via the ligand L. The intrinsic binding constant K(b) values for 1 (5.00 x 10(5) M(-1)) and L (1.65 x 10(5) M(-1)) were determined by absorption titration and calculated with the model of McGhee and Von Hippel. Biological tests against four different cell lines (HL-60, KB, Hela and BGC-823) in vitro showed that the complex had significant antitumor properties since the 50% inhibition concentrations (IC(50)) of the complex were within a microM range similar to those of antitumor drug 5-fluorouracil.