[1] Many regions of the world are facing formidable freshwater scarcity. Although there is substantial scope for economizing on the consumption of water without affecting its service level, the main response to water scarcity has been to increase the supply. To a large extent, this is done by transporting water from places where it is abundant to places where it is scarce. At a smaller scale and without a lot of public and political attention, people have started to tap into the sheer limitless resource of desalinated water. This study looks at the development of desalination and its costs over time. The unit costs of desalinated water for five main processes are evaluated, followed by regressions to analyze the main influencing factors to the costs. The unit costs for all processes have fallen considerably over the years. This study suggests that a cost of $1/m 3 for seawater desalination and $0.6/m 3 for brackish water would be feasible today. The costs will continue to decline in the future as technology progresses. In addition, a literature review on the costs of water transport is conducted in order to estimate the total cost of desalination and the transport of desalinated water to selected water stress cities. Transport costs range from a few cents per cubic meter to over a dollar. A 100 m vertical lift is about as costly as a 100 km horizontal transport ($0.05-0.06/m 3 ). Transport makes desalinated water prohibitively expensive in highlands and continental interiors but not elsewhere.

BackgroundAlthough fibroblast-to-myocyte electrical coupling is experimentally suggested, electrophysiology of cardiac fibroblasts is not as well established as contractile cardiac myocytes. The present study was therefore designed to characterize ion channels in cultured human cardiac fibroblasts.Methods and FindingsA whole-cell patch voltage clamp technique and RT-PCR were employed to determine ion channels expression and their molecular identities. We found that multiple ion channels were heterogeneously expressed in human cardiac fibroblasts. These include a big conductance Ca2+-activated K+ current (BKCa) in most (88%) human cardiac fibroblasts, a delayed rectifier K+ current (IKDR) and a transient outward K+ current (Ito) in a small population (15 and 14%, respectively) of cells, an inwardly-rectifying K+ current (IKir) in 24% of cells, and a chloride current (ICl) in 7% of cells under isotonic conditions. In addition, two types of voltage-gated Na+ currents (INa) with distinct properties were present in most (61%) human cardiac fibroblasts. One was a slowly inactivated current with a persistent component, sensitive to tetrodotoxin (TTX) inhibition (INa.TTX, IC50 = 7.8 nM), the other was a rapidly inactivated current, relatively resistant to TTX (INa.TTXR, IC50 = 1.8 µM). RT-PCR revealed the molecular identities (mRNAs) of these ion channels in human cardiac fibroblasts, including KCa.1.1 (responsible for BKCa), Kv1.5, Kv1.6 (responsible for IKDR), Kv4.2, Kv4.3 (responsible for Ito), Kir2.1, Kir2.3 (for IKir), Clnc3 (for ICl), NaV1.2, NaV1.3, NaV1.6, NaV1.7 (for INa.TTX), and NaV1.5 (for INa.TTXR).ConclusionsThese results provide the first information that multiple ion channels are present in cultured human cardiac fibroblasts, and suggest the potential contribution of these ion channels to fibroblast-myocytes electrical coupling.

In this work, a new set of amino acid descriptors, i.e., VHSE (principal components score Vectors of Hydrophobic, Steric, and Electronic properties), is derived from principal components analysis (PCA) on independent families of 18 hydrophobic properties, 17 steric properties, and 15 electronic properties, respectively, which are included in total 50 physicochemical variables of 20 coded amino acids. Using the stepwise multiple regression (SMR) method combined with partial least squares (PLS), the VHSE scales are then applied to QSAR studies of bitter-tasting dipeptides (BTD), angiotensin-converting enzyme (ACE) inhibitors, and bradykinin-potentiating pentapeptides (BPP). To validate the predictive power of resulting models, external validation are also performed. A comparison of the results to those obtained with z scores and other two-dimensional (2D) or three-dimensional(3D) descriptors shows that the VHSE scales are comparable for parameterizing the structural variability of the peptide series.

No abstract

Abstract:Regional haze episodes have occurred frequently in eastern China over the past decades. As a critical indicator to evaluate air quality, the mass concentration of ambient fine particulate matters smaller than 2.5 µm in aerodynamic diameter (PM 2.5 ) is involved in many studies. To overcome the limitations of ground measurements on PM 2.5 concentration, which is featured in disperse representation and coarse coverage, many statistical models were developed to depict the relationship between ground-level PM 2.5 and satellite-derived aerosol optical depth (AOD). However, the current satellite-derived AOD products and statistical models on PM 2.5 -AOD are insufficient to investigate PM 2.5 characteristics at the urban scale, in that spatial resolution is crucial to identify the relationship between PM 2.5 and anthropogenic activities. This paper presents a geographically and temporally weighted regression (GTWR) model to generate ground-level PM 2.5 concentrations from satellite-derived 500 m AOD. The GTWR model incorporates the SARA (simplified high resolution MODIS aerosol retrieval algorithm) AOD product with meteorological variables, including planetary boundary layer height (PBLH), relative humidity (RH), wind speed (WS), and temperature (TEMP) extracted from WRF (weather research and forecasting) assimilation to depict the spatio-temporal dynamics in the PM 2.5 -AOD relationship. The estimated ground-level PM 2.5 concentration has 500 m resolution at the MODIS satellite's overpass moments twice a day, which can be used for air quality monitoring and haze tracking at the urban and regional scale. To test the performance of the GTWR model, a case study was carried out in a region covering the adjacent parts of Jiangsu, Shandong, Henan, and Anhui provinces in central China. A cross validation was done to evaluate the performance of the GTWR model. Compared with OLS, GWR, and TWR models, the GTWR model obtained the highest value of coefficient of determination (R 2 ) and the lowest values of mean absolute difference (MAD), root mean square error (RMSE), and mean absolute percentage error (MAPE).

No abstract

Three new arylnaphthalide lignans named 6'-hydroxy justicidin A (1), 6'-hydroxy justicidin B (2) and 6'-hydroxy justicidin C (3) have been isolated from the whole plant of Justicia procumbens, together with four known ones, neojusticin A (4), chinensinaphthol methyl ester (5), isodiphyllin (6) and taiwanin C (7). The complete assignments of 1H and 13C NMR chemical shifts for the new lignans and the 13C NMR chemical shifts for the known lignans were obtained for the first time by means of 2D NMR techniques, including HSQC and HMBC.

We present a new, global database on tourist destinations. The database differs from other databases in that it includes both domestic and international tourists; and it contains, for the most important destinations, data at national level as well as at lower administrative levels. Missing observations are interpolated using statistical models. The data are freely accessible on the internet. Copyright © 2007 John Wiley & Sons, Ltd.