Application of an Optimization Model for the Sustainable Water Resource Management of River Basins

Water Resources Management - An optimization model for the sustainable water resource management that maximizes sustainable net economic benefit over a long-term planning horizon is applied to the...     

An Exceptionally Selective DNA Cooperatively Binding Two Ca2+ Ions

Ca²⁺ is a highly important metal ion in biology and in the environment, and thus there is extensive work in developing sensors for Ca²⁺ detection. Although many Ca²⁺‐binding proteins are known, few nucleic acids can selectively bind Ca²⁺. DNA‐based biosensors are attractive for their high stability and excellent programmability. We report a RNA‐cleaving DNAzyme, EtNa, cooperatively binding two Ca²⁺ ions but to only one Mg²⁺. Four DNAzymes with known Ca²⁺‐dependent activity were compared, and the EtNa had the best selectivity for Ca²⁺. The EtNa is 90 times more active in Ca²⁺ than in Mg²⁺. Phosphorothioate (PS) modification showed that both non‐bridging oxygen atoms at the scissile phosphate contribute equally to Ca²⁺ binding. The pH–rate profile suggests two concurrent deprotonation reactions. EtNa was further engineered for Ca²⁺ sensing, and found to have a detection limit of 17 μm Ca²⁺ and excellent selectivity. The detection of Ca²⁺ in tap water was performed, and the result was comparable with that by ICP‐MS. This study offers new fundamental insights into Ca²⁺ binding by nucleic acids and improved metal selectivity by having multiple cooperative metal binding sites.     

Digestion of pre‐treated food waste in a hybrid anaerobic solid–liquid (HASL) system

The hybrid anaerobic solid–liquid (HASL) system was developed to be used in industrial‐scale operations to minimize the amount of food waste for disposal in Singapore. Thermal pre‐treatment of food waste at 70 °C for 2 h (experiment E1) or at 150 °C for 1 h (experiment E2) facilitated the hydrolytic and acidogenic processes in the acidogenic reactor and methanogenesis in the methanogenic reactor in the HASL system. The highest dissolved chemical oxygen demands in the effluents from the acidogenic reactors were 17 575, 19 980 and 24 235 mg dm^?3 in the control with food waste without thermal pre‐treatment and experiments E1 and E2, respectively. The maximum concentrations of methanogens in the methanogenic reactor were 2.3 × 10⁷, 3.8 × 10⁷, 4.3 × 10⁷ cells cm^?3 for the control and experiments E1 and E2, respectively. However, the performances of the methanogenic phase in terms of specific activity of methanogens did not differ significantly for the control and experiments E1 and E2. Use of thermally pre‐treated food waste halved the time to produce the same quantity of methane in comparison with anaerobic digestion of fresh food waste. The fluorescent measurements of co‐enzyme F₄₂₀ and oligonucleotide probe Arc915 specifically bound (hybridized) with 16S rRNA were used for monitoring of methanogens during anaerobic digestion of food waste. There was a linear correlation between these parameters and the concentration of methanogens in the effluent from the methanogenic reactor. Copyright © 2005 Society of Chemical Industry     

Effect of fish oil on cancer cachexia and host liver metabolism in rats with prostate tumors

The aim of this study was to investigate whether tumor-induced cachexia and aberrations in host liver metabolism, induced by the MAT-LyLu variant of the Dunning prostate tumor, could be prevented by ω3 fatty acids from fish oil. On day 0, adult Copenhagen-Fisher rats fed normal chowad libitum were inoculated with 10⁶ MAT-LyLu cells (n=14) or saline (n=9). On day 7, when tumors were palpable, four tumor-bearing (TB) and four nontumorbearing (NTB) rats were put on isocaloric diets with 50% of total energy as fish oil. The introduction of fish oil-enriched diets caused a reduction in energy intake to less than half of the energy intake by animals fed normal diets during days 7–14 (difference by dietary group: NTB,P<0.001; TB,P<0.001). During days 14–21, energy intake in fish oil-fed animals returned to approximately 75% of energy intake by animals fed normal diets (difference by dietary group: NTB,P<0.003; TB,P=0.001). Carcass weight of animals on day 21, when the study was terminated, was significantly related to initial weight (P=0.05) and mean food intake during the study (P=0.01). When data were adjusted for these variables using analysis of covariance, with NTB animals on normal diets being the reference group, significant loss of carcass weight was observed in TB animals on normal diets only (mean ±SEM 58±10 g loss,P<0.001), but not in TB animals on fish oil diets (8±18 g loss,P=0.67). This positive effect of fish oil diets on carcass weight in TB animals was statistically significant (50±19 g,P<0.02), implicating that the fish oil enriched diet inhibited tumor-induced weight loss by more than 85%. No effect of fish oil diets on tumor growth was detected. In all TB animals, regardless of diet, hepatic [P_i]/adenosine triphosphate] ratios measured by³¹P magnetic resonance spectroscopy (MRS)in vivo andin vitro were elevated, and absolute concentrations of phosphocholine, glycerophosphocho-line, glycerophosphoethanolamine and glucose-6-phosphate as determined by³¹P MRSin vitro were reduced. Ultrastructural studies of liver tissue revealed increased numbers of mitochondria and increased amounts of endoplasmic reticulum in the host liver of TB animals, without differences between dietary group. In conclusion, fish oil supplementation partially inhibited MAT-LyLu tumor-induced cachexia, but did not prevent the majority of³¹P MRS-detectable alterations in host liver metabolism.     

Preparation and characterisation of chemisorbents based on heteropolyacids supported on synthetic mesoporous carbons and silica

The preparation of chemisorbents based on tungsto- and molybdophosphoric acids supported on two types of synthetic mesoporous carbons and two types of mesoporous silica is described. Strong solid acids with good accessibility to acid sites may potentially be effective adsorbents for the removal of basic molecular impurities, such as amines, from ultrapure manufacturing environments. Prepared materials were characterised by scanning electron microscopy, nitrogen adsorption, Fourier-transform infrared spectroscopy, powder X-ray diffraction, and equilibrium ammonia uptake. Composites of SBA-15 with heteropolyacids were synthesised. It was shown that the inclusion of HPAs into SBA-15 results in the loss of long range order. Adsorbents based on the HPAs impregnated into the supports with the open-pore morphology (Novacarb and SBA-15) were found to be promising materials. A composite of tungstophosphoric acid with sol–gel SiO₂ was found to have the highest ammonia uptake.     

High performance encapsulation structures utilizing Russian Doll architectures

A Russian Doll encapsulation architecture utilizing pairs of free-standing barrier films and epoxy seals separated by nitrogen spacers is presented, enabling the use of low-cost epoxy to attach two or more free-standing barrier films to a substrate with improved barrier performance. The performance of various Russian Doll encapsulations was evaluated with the calcium thin film optical transmission test, showing improved performance of the Russian doll configuration relative to a non-nested barrier/spacer architecture, and demonstrating that water vapor transmission rates (WVTR) of 0.00021 g/(m², day) or below can be achieved with low-cost materials in this architecture. This WVTR correlates to a predicted lifetime of more than 10 years for bulk heterojunction solar cell modules fabricated and tested by Konarka Technologies (Lowell, MA, USA).     

Optimization of Multiple Reservoir Networks for Sedimentation Control

An optimal control methodology is developed to evaluate reservoir management policies that minimize sediment scour and deposition in multiple-reservoir river networks. Consideration is given to adverse effects occurring in both reservoirs and rivers of a hydraulic network. The sedimentation problem is formulated as a discrete-time optimal control problem in which a successive approximation linear quadratic regulator optimization scheme is coupled with the U.S. Army Corps of Engineers HEC-6 sediment transport simulation model. Operational constraints imposed on reservoir storage levels and releases are accommodated using either a bracket or hyperbolic penalty function method. The resulting model also allows the user to evaluate policies that alternatively maximize sedimentation or consider adverse effects only at specified locations. Comparisons of the computational efficiencies between the successive approximation linear quadratic regulator and differential dynamic programming methodology and between different penalty functions are performed. Capabilities of the model are demonstrated through applications to a hypothetical three-reservoir network and the Yazoo Basin river-reservoir network in Mississippi.     

An automatic controller extractor for HDL descriptions at the RTL

Extracting controlling finite-state machines can significantly reduce state space and thereby speed functional verification. The controller extraction algorithm uses an approach that frees it from restrictions on HDL code writing style