Performance evaluation of artificial neural network approaches in forecasting reservoir inflow

This study investigates the potential of Time Lag Recurrent Neural Networks (TLRN) for modeling the daily inflow into Eleviyan reservoir, Iran. TLRN are extended with short term memory structures that have local recurrent connections, thus making them an appropriate model for processing temporal (time-varying) information. For this study, the daily inflow into Eleviyan reservoir between years 2004–2007 was considered. To compare the performance of TLRN, a back propagation neural network was used. The TLRN model with gamma memory structure, eight input layer nodes, two hidden layer and one output layer (8-2-1) was found performing best out of three different models used in forecasting daily inflow. A comparison of results with back propagation neural network suggest that neither TLRN nor back propagation approaches were good in forecasting high inflow but, both approaches perform well when used to forecast low inflow values. However, statistical test suggests that both TLRN and back propagation neural network models were able to reproduce similar basic statistics as that of the actual data.     

Study of the structural changes in urea-formaldehyde condensates during synthesis

Chemical constitution of urea-formaldehyde resins in synthesis and in storage was determined using ¹³C NMR spectroscopy. Methylolation, methylene and dimethylene ether bond-forming reactions were discussed. The changes in the content of structural elements with secondary and tertiary amino groups of urea at various stages were followed. The resin synthesis technology was used, which considers the requirement in low free formaldehyde content, connected with somewhat smaller storage stability of resins.     

Pressure versus pH phase diagrams of two lysozymes crystallized in agarose gel

The effect of hydrostatic pressure and pH on the crystallization of tetragonal hen lysozyme crystals (HeL, M _r 14,300) and hexagonal turkey lysozyme crystals (TeL, M _r 14,200) in agarose gel was studied. Samples (adjusted to a pH in the range 4–6) were pressurized at 0.1–100?MPa for nine days at 293?K. The morphology and number of crystals as well as protein solubility were analyzed after depressurization. For both proteins and whatever the pH, a higher pressure resulted in greater numbers of crystals and greater solubility values. At any pressure, the solubility and number of crystals were lower at the highest pH. Thus the physical chemical parameters and the outcome of the crystallization process are more affected by pressure at pH 4.0 than at pH 6.0. In the case of HeL, either high pressure or high pH induces a transition from the initial tetragonal form to an orthorhombic one. The observed effects are related to minor differences in the macromolecular structures.     

Speciation of239Np in neutron irradiated uranium compounds

The chemical state of²³⁹Np formed in the -decay of²³⁹U produced by thermal neutron capture in²³⁹U, has been determined in simple uranium compounds as well as in macrocyclic complexes of this element. It is shown that the behavior of neptunium depends on such factors as the nature of the target, the counter-ion of the complex, the dissolution medium and the pH. The change of the oxidation state of²³⁹Np with time and the effect of the presence of macroscopic amounts of²³⁸UO ₂ ²⁺ and of²³⁸U(IV) in the solution have also been investigated. The results are discussed in terms of the hot atom behavior of²³⁹U and of the genuine effects of -decay.     

Automating proteome analysis: improvements in throughput, quality and accuracy of protein identification by peptide mass fingerprinting

The use of robots has major effects on maximizing the proteomic workflow required in an increasing number of high-throughput projects and on increasing the quality of the data. In peptide mass finger printing (PMF), automation of steps downstream of two-dimensional gel electrophoresis is essential. To achieve this goal, the workflow must be fluid. We have developed tools using macros written in Microsoft Excel and Word to complete the automation of our platform. Additionally, because sample preparation is crucial for identification of proteins by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, we optimized a sandwich method usable by any robot for spotting digests on a MALDI target. This procedure enables further efficient automated washing steps directly on the MALDI target. The success rate of PMF identification was evaluated for the automated sandwich method, and for the dried-droplet method implemented on the robot as recommended by the manufacturer. Of the two methods, the sandwich method achieved the highest identification success rate and sequence coverage of proteins.     

High-speed analysis of dansyl derivatives of polyamines

Summary Analytical conditions for the high-speed, reversed-phase, liquid chromatographic of a diamine (putrescine) and polyamines (spermine and spermidine) were determined. Various elution modes were employed using the same mobile phase constituents: 20mM sodium heptane sulfonate and 20mM acetic acid as solvent A and, pure acetonitrile as solvent B. Samples were derivatized with dansyl chloride before injection.Under isocratic conditions, the separation of the three polyamines was achieved in 7 min. The use of a linear elution gradient led to the same analytical time but with a better resolution of the putrescine peak from non-polyamine frontal peaks. For these measurements, the sample size was 5l. This volume was increased to 20l and the use of a steep gradient combined with the peak-compression technique allowed a fast analysis in 2–3 minutes, which may be compared with a 30 min run time necessary when a conventional column is used.     

Characterisation of passive films formed on low carbon steel in borate buffer solution (pH 9.2) by electrochemical impedance spectroscopy

The comprehension of passivity and its protective character against corrosion is closely connected with the electronic properties of passive films. Passive films formed anodically on carbon steel in borate/boric acid solution, pH 9.2, have been characterised by electrochemical impedance spectroscopy (EIS). Mott-Schottky plots and impedance measurements were made on films formed at different potentials and times. The investigation allowed the determination of the semiconductive properties of the films. The results of the capacitance response indicate that the passive films behave like highly doped n-type semiconductors, showing that the passive film properties are dominated by iron. The value of donors density (N_D) for the passive film is of the order of 10²¹ cm⁻³ and decreases with increasing formation time and potential, indicating that defects decrease with increasing film thickness. Based on the information about the physical phenomena, an equivalent circuit is proposed to fit the experimental data, leading to determination of anodic film capacitance and film resistance.     

Synthesis,cytotoxic activity,and fluorescence properties of a set of novel 3-hydroxyquinolin-4(1H)-ones

The targeted solid-phase synthesis of 3-hydroxyquinolin-4(1H)-one derivatives is described. Primary and secondary amines, 3-amino-4-(methoxycarbonyl)benzoic acid and 2-bromo-1-(4-chloro-3-nitrophenyl)ethanone were used as starting materials. The structures of the final compounds were designed in accordance with previous information obtained from structure–activity relationship studies of similar cytotoxic derivatives. Representative prepared compounds were subjected to in vitro screening of cytotoxic activity against various cancer cell lines; the results obtained are discussed. Fluorescence properties of selected compounds were also studied to compare the data with those obtained in analogous derivatives.     

Generalized Rotation Surfaces in {\mathbb E^4}

In the present study we consider generalized rotation surfaces imbedded in an Euclidean space of four dimensions. We also give some special examples of these surfaces in ${\mathbb E^4}$ . Further, the curvature properties of these surfaces are investigated. We give necessary and sufficient conditions for generalized rotation surfaces to become pseudo-umbilical. We also show that every general rotation surface is Chen surface in ${\mathbb E^4}$ . Finally we give some examples of generalized rotation surfaces in ${\mathbb E^4}$ .