Investigating the interactive mechanisms between surface water and groundwater over the Jhuoshuei river basin in central Taiwan

In Taiwan, groundwater commonly becomes important water resources in dry periods, and/or areas lack of water storage facility due to its low cost, steady water supply and good water quality. However, improper groundwater development brings about serious decreases in groundwater levels and land subsidence which causes disasters, such as seawater intrusion or soil salination, accompanied with environmental and economic losses. It is critical to develop strategies for water resources conservation in mountainous areas. The complex heterogeneity of mountainous physiographic environment makes it challenging in the forecasts of groundwater level variations, particularly in mountainous areas. Artificial neural networks (ANNs) have been recognized as an effective modeling tool for complex nonlinear systems in the last two decades. This study aims to investigate the interactive mechanisms of groundwater at the mountainous areas of the Jhuoshuei river basin in central Taiwan through analyzing and modeling the groundwater level variations. Several issues are discussed in this study, which includes the correlation between groundwater level variation and rainfall as well as streamflow, the identification of groundwater recharge patterns and effective rainfall thresholds for estimating groundwater level variations. The results indicate: (1) the daily variation of groundwater level is closely correlated with river flow and one-day antecedent rainfall based on correlation analyses; (2) effective rainfall thresholds can be identified successfully; (3) groundwater level variations can be classified into four types for monitoring wells; and (4) the daily variations of groundwater level can be well estimated by constructed ANNs. The identified interactive mechanisms between surface water and groundwater can facilitate the mountainous water resource conservation strategy for better water management, especially irrigation water supply and for alleviating land subsidence in downstream areas in the future.     

Human T-cell receptor alpha-chain genes: location on chromosome 14

The genes encoding the alpha chain of the human T-cell receptor have been mapped to chromosome 14, the chromosome on which the human immunoglobulin heavy chain locus resides. Thus, genes encoding two different classes of antigen receptor are present on the same chromosome. Furthermore, breaks involving chromosome 14 are frequently seen in tumors of T-cell origin. The potential relation of these chromosome abnormalities to alpha-chain genes is discussed.     

The Prp19p-associated complex in spliceosome activation

During spliceosome activation, a large structural rearrangement occurs that involves the release of two small nuclear RNAs, U1 and U4, and the addition of a protein complex associated with Prp19p. We show here that the Prp19p-associated complex is required for stable association of U5 and U6 with the spliceosome after U4 is dissociated. Ultraviolet crosslinking analysis revealed the existence of two modes of base pairing between U6 and the 5' splice site, as well as a switch of such base pairing from one to the other that required the Prp19p-associated complex during spliceosome activation. Moreover, a Prp19p-dependent structural change in U6 small nuclear ribonucleoprotein particles was detected that involves destabilization of Sm-like (Lsm) proteins to bring about interactions between the Lsm binding site of U6 and the intron sequence near the 5' splice site, indicating dynamic association of Lsm with U6 and a direct role of Lsm proteins in activation of the spliceosome.     

The 18O/16O and 17O/16O ratios in atmospheric nitrous oxide: A mass-independent anomaly

Measurements of the oxygen isotope ratios (18O/16O and 17O/16O) in atmospheric nitrous oxide (N2O) from La Jolla, Pasadena, and the White Mountain Research Station (elevation, 3801 meters) in California and the White Sands Missile Range in New Mexico show that N2O has a mass-independent composition. These data suggest the presence of a previously undefined atmospheric process. The La Jolla samples can be explained by a mixing between an atmospherically derived source of mass-independent N2O and biologically derived mass-dependent N2O. Possible origins of the mass-independent anomaly in N2O are discussed.     

Benzoquinolinediones: activity as insect teratogens

Morphological abnormalities including extra compound eyes, extra heads, and distally duplicated legs were generated in cricket embryos by treating eggs with single doses of either benz[g]isoquinoline-5,10-dione or benzo[h]quinoline-5,6-dione. Slight structural modifications of the molecules resulted in a loss of teratogenic activity, although embryotoxicity occurred. These potent insect teratogens can be used for analysis of developmental events during embryogenesis.     

Menelloides C and D, new sesquiterpenoids from the Gorgonian coral Menella sp

Two new metabolites, including a lindenane-type sesquiterpenoid, menelloide C (1), and a germacrane-type sesquiterpenoid, menelloide D (2), were isolated from a Formosan gorgonian coral identified as Menella sp. The structures of 1 and 2 were established by spectroscopic methods and 2 displayed a weak inhibitory effect on the release of elastase by human neutrophils.     

Lobocrassins A-E: new cembrane-type diterpenoids from the soft coral Lobophytum crassum

Five new cembrane-type diterpenoids, lobocrassins A-E (1-5), were isolated from the soft coral Lobophytum crassum. The structures of cembranes 1-5 were established by spectroscopic and chemical methods and by comparison of the spectral data with those of known cembrane analogues. Lobocrassin A (1) is the first cembranoid possessing an α-chloromethyl-α-hydroxy-γ-lactone functionality and is the first chlorinated cembranoid from soft corals belonging to the genus Lobophytum. Lobocrassins B (2) and C (3) were found to be the stereoisomers of the known cembranes, 14-deoxycrassin (6) and pseudoplexaurol (7), respectively. Lobocrassin B (2) exhibited modest cytotoxicity toward K562, CCRF-CEM, Molt4, and HepG2 tumor cells and displayed significant inhibitory effects on the generation of superoxide anion and the release of elastase by human neutrophils.