bluuebunny/crossref_metadata_2025 huggingface dataset:
Hepatocyte RXRalpha deficiency in matured and aged mice: impact on the expression of cancer-related hepatic genes in a gender-specific manner
Authors: Guo Minglei , Gong Lei , He Lin , Lehman-McKeeman Lois , Wan Yu-Jui Yvonne
Published: August 2008

Background

The occurrence of liver cancer is higher in males than in females, and the incidence increases during aging. Signaling pathways regulated by retinoid × receptor α (RXRα) are involved in hepatocellular carcinogenesis. The phenotype of hepatocyte RXRα deficient mice is different between genders. To explore the impact of hepatocyte RXRα deficiency on gender-dependent hepatic gene expression, we compared the expression profiles of cancer-related genes in 6 and 24 month old male and female mice.

Results

In 6 month old mice, male mutant mice showed more cancer-related genes with alteration in mRNA levels than females did (195 vs. 60). In aged mice (24 month), female mutant mice showed greater deviation in mRNA expression levels of cancer-related genes than their male counterparts (149 vs. 82). The genes were classified into five categories according to their role in carcinogenesis: apoptosis, metastasis, cell growth, stress, and immune respnse. In each category, dependent upon age and gender, the genes as well as the number of genes with altered mRNA levels due to RXRα deficiency varies.

Conclusion

The change in hepatic cancer-related gene expression profiles due to RXRα deficiency was gender- and age-dependent. The alteration of mRNA levels of cancer-related genes implied that aberrant RXRα signaling could potentially increase the risk of liver cancer and that retinoid signaling might contribute to gender- and age-associated liver cancer incidence.
A controlled trial of protein enrichment of meal replacements for weight reduction with retention of lean body mass
Authors: Treyzon Leo , Chen Steve , Hong Kurt , Yan Eric , Carpenter Catherine L , Thames Gail , Bowerman Susan , Wang He-Jing , Elashoff Robert , Li Zhaoping
Published: August 2008

Background

While high protein diets have been shown to improve satiety and retention of lean body mass (LBM), this study was designed to determine effects of a protein-enriched meal replacement (MR) on weight loss and LBM retention by comparison to an isocaloric carbohydrate-enriched MR within customized diet plans utilizing MR to achieve high protein or standard protein intakes.

Methods

Single blind, placebo-controlled, randomized outpatient weight loss trial in 100 obese men and women comparing two isocaloric meal plans utilizing a standard MR to which was added supplementary protein or carbohydrate powder. MR was used twice daily (one meal, one snack). One additional meal was included in the meal plan designed to achieve individualized protein intakes of either 1) 2.2 g protein/kg of LBM per day [high protein diet (HP)] or 2) 1.1 g protein/kg LBM/day standard protein diet (SP). LBM was determined using bioelectrical impedance analysis (BIA). Body weight, body composition, and lipid profiles were measured at baseline and 12 weeks.

Results

Eighty-five subjects completed the study. Both HP and SP MR were well tolerated, with no adverse effects. There were no differences in weight loss at 12 weeks (-4.19 ± 0.5 kg for HP group and -3.72 ± 0.7 kg for SP group, p > 0.1). Subjects in the HP group lost significantly more fat weight than the SP group (HP = -1.65 ± 0.63 kg; SP = -0.64 ± 0.79 kg, P = 0.05) as estimated by BIA. There were no significant differences in lipids nor fasting blood glucose between groups, but within the HP group a significant decrease in cholesterol and LDL cholesterol was noted at 12 weeks. This was not seen in the SP group.

Conclusion

Higher protein MR within a higher protein diet resulted in similar overall weight loss as the standard protein MR plan over 12 weeks. However, there was significantly more fat loss in the HP group but no significant difference in lean body mass. In this trial, subject compliance with both the standard and protein-enriched MR strategy for weight loss may have obscured any effect of increased protein on weight loss demonstrated in prior weight loss studies using whole food diets.
Separation of reference motions and elastic deformations in an elastic multi-body system
Authors: Offner G , Eizenberger T , Priebsch H H
Published: August 2008

The computational simulation of multi-body dynamics (MBD) of moving structural components is one of the most challenging objectives in the design analysis work of automotive engineers. These simulations are a need to assess the vibro-acoustic quality of new products in the early development stage and can reduce development time and costs significantly. The concept of elastic MBD is based on dividing the non-linear mechanic system into subsystems with linear elastic behaviour (bodies) and non-linearities occurring only at the connections (joints) between these subsystems. Because of the non-linear characteristic of the system, the dynamic simulation has to be solved in time domain via numerical time integration. Both the necessary small time-step sizes and the iterative solution scheme within one time step imply large computational effort. Thus, the improvement of the efficiency and the stability are main targets for the software development.

This article presents two variants of modelling linear elastic components via a multi-body model. The main difference between the two variants is in the strategy used for the separation of reference (global) motions and elastic deformations (small motions). The first variant applies a projection strategy, whereas the second variant considers reference conditions that are based on a minimum relative kinetic energy or on a minimal square average displacement approach. This article describes the mathematical modelling of the two variants, which based on the floating frame of reference formulation. On the basis of the theoretical formulation, a comparison of the two strategies from application as well as numerical and algorithmic point of view is presented. Consequently, the advantages and the disadvantages of the two approaches will be analysed.

The results section compares the two presented methods, which were applied for the simulation of the dynamics of two crankshaft models. First, a crankshaft of a five-cylinder combustion engine is analysed. The second investigated example is a crankshaft of a one-cylinder engine with special consideration of different strategies for the applied reference conditions. Both the obtained calculation results and the computational performance in terms of CPU time are discussed.
Influence of the contact—impact force model on the dynamic response of multi-body systems
Authors: Flores P , Ambrósio J , Claro J C P , Lankarani H M
Published: August 2008

This work deals with contact—impact force models for both spherical and cylindrical contact surfaces. The incorporation of the friction phenomenon, based on the Coulomb friction law, is also discussed together with an effective computational strategy, which includes the automatic step size selection procedure. Impacts within a revolute clearance joint in a basic slider—crank mechanism are used as an example to compare the different contact force models. The collision is a prominent phenomenon in many multi-body systems such as mechanisms with intermittent motion, kinematic discontinuities, and clearance joints. As a result of an impact, the values of the system state variables change very fast, eventually looking like discontinuities in the system velocities and accelerations. The impact is characterized by large forces that are applied and removed in a short time period. The knowledge of the peak forces developed in the impact process is very important for the dynamic analysis of multi-body systems and it has consequences in the design process. The model for the contact—impact force must consider the material and geometric properties of the colliding surfaces, consider information on the impact velocity, contribute to an efficient integration, and account for some level of energy dissipation. These characteristics are ensured with a continuous contact force model, in which the deformation and contact forces are considered as continuous functions.
Study on the Nitric Oxide Generating Effects from Aristolochic Acidin vitro
Authors: Xu Qin , Ma Chaomei , Wang Wei , Fu Xiang , Tang Chunyan , Hattori Masao
Published: August 2008

In this study, an in vitro nitric oxide (NO)-assay system based on the Griess reaction was used to investigate the (NO)-generating effects of aristolochic acid (AA) for the first time. AA was separated into its different components, aristolochic acid I (AAI) and aristolochic acid II (AAII), by preparative HPLC. AAI and AAII were incubated with human intestine bacteria (HIB) or rat intestine bacteria (RIB). A NO mixture generated from AAI and AAII by intestinal bacteria was observed and denitroso metabolites of AAI or AAII were detected in vitro by liquid chromatography/tandem mass spectrometry. Therefore, NO generation might be closely related to the metabolic process of AA in vitro. It suggested that one possible mechanism for the toxicity of AA may be due to the generation of NO from these compounds by intestinal bacteria.
In Search of Charisma: The Falun Gong Diaspora
Authors: Ownby David
Published: August 2008

Based on the author's fieldwork between 1999 and 2002, this essay examines the question of charisma among Falun Gong practitioners in the Chinese diaspora in North America. It explores two types of charisma: an embodied charisma where the individual practitioner's expectations of the extraordinary are experienced as bodily transformation; and a charisma of martyrdom based on a teleology of resistance to the People's Republic of China's campaign against Falun Gong.
Cortisol response to ACTH stimulation correlates with blood interleukin 6 concentration in healthy humans
Authors: Žarković Miloš , Ignjatović Svetlana , Dajak Marijana , Ćirić Jasmina , Beleslin Biljana , Savić Slavica , Stojković Mirjana , Bulat Petar , Trbojević Božo
Published: August 2008

Objective

Interleukin 6 (IL6) has the ability to influence each level of the hypothalamo-pituitary–adrenocortical (HPA) axis. The aim of the study was to test whether IL6 concentration correlates with the adrenal cortex response to ACTH in healthy humans. We postulated that higher basal IL6 concentration would be associated with the higher cortisol response to the stimulation.

Design and methods

Basal IL6 concentration was measured and a low dose (1 μg) ACTH test was performed to assess cortisol response. Twenty-seven apparently healthy subjects (11 male, 16 female, mean age 31.1 years, age range 22–47 years) were included in the study.

Results

Data are presented as mean±s.e.m. Basal IL6 level was 0.84±0.10 pg/ml. Basal cortisol was 351.9±18.3 nmol/l. Maximal cortisol during synacthen test was 653.0±20.6 nmol/l. Maximal cortisol increment was 301.1±20.0 nmol/l. IL6 concentration was not correlated with basal or maximal cortisol concentration, but correlated significantly with cortisol increment (r=0.63, 95% confidence interval) 0.42–0.83).

Conclusions

In our study, we found that higher basal IL6 concentration is associated with the higher cortisol response to ACTH stimulation. Based on previous research and our data, IL6, even in low concentrations and under physiologic conditions, modulates adrenal cortex responsivity to ACTH. Therefore, it seems that immune modulation of HPA axis is also present under physiologic and not only pathologic conditions.
Synthesis and performance of a photocatalytic titania-hydroxyapatite composite
Authors: Phonthammachai N. , Kim J. , White T.J.
Published: August 2008

The photocatalytic degradation of methylene blue (MB) over a porous titania-hydroxyapatite (HAp) composite under ultraviolet radiation was studied. The catalyst was prepared by coating porous HAp with a titanium butoxide [Ti(OBu)4] sol at titania loadings of 17–49 wt%. Quantitative powder x-ray diffraction showed higher proportions of anatase as the calcination temperature increased from 500 to 800 °C due to crystallization of an amorphous precursor. The transformation of anatase to rutile was delayed until 900 °C, demonstrating the high thermal stability of the composite. Decomposition of HAp to α- and β- tricalcium phosphates takes place at 900 °C and is accompanied by the formation of perovskite at 1000 °C. A systematic study of the influence of calcination temperature and titania:HAp ratios demonstrated that for the optimal material, a surface area of 100 m2 g−1 was obtained at a titania loading of 49 wt% and calcination temperature of 600 °C. A highly dispersed suspension of finely ground titania-HAp enhanced the photodegradation of MB, allowed a high percentage recovery of catalyst, and was shown to be recyclable.
Electron energy loss spectroscopy of Na in Na, Na2O, and silicate glasses
Authors: Jiang Nan , Su D. , Spence J.C.H. , Zhou S. , Qiu J.
Published: August 2008

Measuring Na in silicate glasses can be difficult in transmission electron microscopy due to modifications induced by electron irradiation. The modifications involve not only the loss of Na from the illuminated region, but also the formation of Na and Na2O. This work compares the electron energy loss spectroscopy (EELS) of plasmon and Na L23 edge in Na2O–SiO2 glass with those in Na and Na2O. The interpretations of the fine structures in Na L23 edge were also given with the aid of full multiplescattering calculations. It demonstrates that the formation of metallic Na can be easily identified by its bulk plasmon at about 5.8 eV, and the formation of Na2O can be better seen by Na L23-edge fine structure.
Determination of the internal stress and dislocation velocity stress exponent with indentation stress relaxation test
Authors: Xu B.X. , Wang X.M. , Yue Z.F.
Published: August 2008

Indentation stress relaxation tests were carried out on high-purity polycrystalline copper specimens at room temperature with a flat cylindrical indenter. The experimental results showed that the resulting load-time relaxation curves can be described by a power law, which coupled an internal stress and an integral constant between the effective stress and relaxation time. Then the internal stress, integral constant, and dislocation velocity stress exponent can be extracted from load relaxation curves. The derived values from this way were consistent with the results of conventional uniaxial compression stress relaxation tests. These agreements are not only useful to understand deformation (dislocation) mechanisms under the indenter, but also exhibit an attractive potential of measuring nano/micromechanical properties of materials by indentation test.
Positive Hall coefficients obtained from contact misplacement on evident n-type ZnO films and crystals
Authors: Ohgaki Takeshi , Ohashi Naoki , Sugimura Shigeaki , Ryoken Haruki , Sakaguchi Isao , Adachi Yutaka , Haneda Hajime
Published: August 2008

We report on the effect of sample non-uniformity on the results of Hall-effect measurements. False positive Hall coefficients were obtained from an evidently n-type ZnO single crystal, although four electrodes with low contact resistance were made and the Van der Pauw parameter for this electrode configuration was close to 1.00. Further position-sensitive characterization revealed that the false positive Hall coefficient was due to non-uniform electrical properties of the sample. To demonstrate a false positive sign of the Hall coefficient due to sample non-uniformity, we devised a model structure made from evident n-type ZnO thin film and successfully reproduced a false positive Hall coefficient from n-type ZnO.
Study of high-pressure sintering behavior of cBN composites starting with cBN–Al mixtures
Authors: Li Yongjun , Li Sicheng , Lv Ran , Qin Jiaqian , Zhang Jian , Wang Jianghua , Wang Fulong , Kou Zili , He Duanwei
Published: August 2008

Cubic boron nitride (cBN) composites starting with cBN–Al mixtures were sintered on WC-16 wt% Co substrates under static high pressure of 5.0 GPa and at temperatures of 800–1400 °C for 30 min. Vickers hardness of the sintered samples increased with increasing cBN content, and the highest hardness of 32.7 GPa was achieved for the cBN–5 wt% Al specimens sintered at 1400 °C. The reactions between cBN and Al started to occur at about 900 °C, and the reaction products strongly depended on the Al content, sintering temperature, and Co diffusion from the substrates according to the x-ray diffraction (XRD) observations. The high pressure and high temperature in situ resistance measurement indicated that the reactions between cBN and Al could be completed in about 90 s when the temperature was higher than ∼1200 °C at high pressure. The cBN composite sintered at 1200 °C from a cBN–15 wt% Al mixture showed the best cutting performance.
Intermetallic formation induced substrate dissolution in electroless Ni(P)-solder interconnections
Authors: Song Jenn-Ming , Liu Yao-Ren , Su Chien-Wei , Lai Yi-Shao , Chiu Ying-Ta
Published: August 2008

The effect of minor transition metal (TM) additives of Ni, Co, or Zn on the interfacial reactions of the solder joints between Sn–Ag–Cu (SAC) solder and the Cu/Ni(P)/Au substrate was investigated, especially subsequent to multi-reflowing. (Cu,Ni)6Sn5 formed at the interface of all the joints except that of SAC–Ni, of which the interfacial compound was (Ni,Cu)6Sn5. The interfacial compounds of the SAC–Co and SAC–Zn contained a small amount of alloying elements of less than 3 at.%. Two P-rich layers, Ni3P and Ni–Sn–P emerged at the interface of the SAC joints. Nanoindentation analysis indicates that the hardness and Young’s modulus of these two phases were slightly higher than those of the Ni(P) substrate, which were in turn much greater than those of the Cu–Ni–Sn compounds. Worthy of notice is that with TM additions, the Ni–Sn–P phase between Ni3P and interfacial compounds was absent even after 10 reflows. For the SAC–Co joints, the growth of Ni-containing intermetallic compounds within the solder gave rise to the excess Ni dissolution, which caused a discrete Ni3P layer and over-consumed Ni(P) substrate underneath the grooves in-between (Cu, Ni)6Sn5 scallop grains at the interface. This phenomenon is presented for the first time, and the mechanism is proposed in this study.
Molecular cloning and mRNA expression analysis of two GH secretagogue receptor transcripts in orange-spotted grouper (Epinephelus coioides)
Authors: Chen Ting , Tang Zhiguo , Yan Aifen , Li Wensheng , Lin Haoran
Published: August 2008

GH secretagogue receptor (GHSR) is the receptor of ghrelin, a circulating GH-releasing and appetite-inducing hormone. In this paper, two Ghsr cDNAs, gpGhsr1a and gpGhsr1b, were identified and characterized in a teleost, the orange-spotted grouper (Epinephelus coioides). The gpGHSR1a is 1512 bp in length with an open reading frame (ORF) that encodes a protein of 383 amino acids with seven transmembrane (TM) domains, while the 1703 bp gpGHSR1b contains an ORF encoding for 303 amino acids with five TM domains. Comparison between cDNA and gene sequences showed that the two transcripts are two alternative splicing forms of a single gpGhsr gene. Tissue distribution and ontogeny of two gpGhsr mRNAs were examined by RT-PCR. The gpGHSR1a is mainly expressed in brain and pituitary gland, when compared with a more widespread expression of gpGHSR1b. During embryonic and larval development, the gpGhsr1b mRNA appears before the gpGhsr1a mRNA. Furthermore, quantitative real-time PCR performed on brain showed that both transcripts have the highest expression level in the pituitary gland. The expression level of gpGHSR1a was generally higher than that of gpGHSR1b. GHSR expressing cells were also detected widely in grouper brain by in situ hybridization, with a broader distribution than previous reports in mammals. Finally, an in vitro study showed that expression of both gpGHSR transcripts in pituitary and hypothalamus is downregulated by GH and ghrelin but not by des-acyl ghrelin, and this suggests that feedback regulation of GHSR also exists in teleostean fishes.
Integrating ESPs with Intelligent Completions: Options, Benefits and Risks
Authors: Ali M. A. , Shafiq M.
Published: August 2008

Intelligent completions have been in commercial use for over ten years. Application of intelligent completions technology has evolved from intervention-less completion for sub-sea wells to new applications where intelligent completions are delivering better wells through improved efficiency, productivity and hydrocarbon recovery with fewer wells both offshore and on land.

Intelligent completions have proven their value in managing production from multilateral wells, horizontal wells with multiple zones, and wells with heterogeneous reservoirs, using a single wellbore. Their capability to restrict, water or gas production, and improve ultimate recovery has helped optimize overall drilling, completion and production costs.

Electric Submersible Pumps play a key role in producing from oil wells that are incapable of producing naturally at commercially viable rates. ESPs are commonly used in wells which cannot lift the oil to surface due to low reservoir pressure, high water cut, and high back pressure from surface facilities or a combination of all three. As large oilfields around the world mature ESPs will play a major role in maintaining production from these fields.

In order to combine intelligent completion with ESPs several factors need to be considered. This paper will evaluate different options to combine ESPs with intelligent completions and review their respective limitations, benefits and risks.
Slim Intelligent Completions Technology Optimize Production in Maximum Contact, Expandable Liner and Quad Laterals Complex Wells
Authors: Shafiq Muhammad , Ali Athar , Al-Haj Haider , Obaidi Ibrahim , Qazi Muhammad Qasim , Kamal S. M. Mansoor
Published: August 2008

This paper describes an innovative completion solutions with reservoir monitoring and control completion technologies that allows commingled oil production from multi-laterals wells in Shaybah inside expandable liner. Slim intelligent completions technology has been successfully installed in Shaybah field, operated by Saudi Aramco. Included in the description are equipment selection, design and development details, installation procedures, and "lessons learned" after installation of the fully hydraulic tubing-retrievable advance completion system with digital permanent down hole monitoring system. Intelligent completions allows individual lateral testing, allocation of production rates to optimize each lateral contribution and the overall commingled well rate. Along with real time monitoring, sustainability of well rate will be extended by timely reacting to any changes to reservoir and well conditions.

Using variable positions flow control valve, early water breakthrough can be delayed to increase recovery factor. Monitoring the flowing pressure in real time allows producing the well at optimum rate; i.e., above bubble point pressure. Ultimately, intelligent completions will limit the water handling at the surface, minimize future intervention and concurrently increase the recovery factor for MRC (Maximum Reservoir Contact) wells.
Cementing High Pressure Formations in the Kingdom of Saudi Arabia
Authors: Berg S. , Noor S. , Barnett N. , Al Yami H. E. , Nawaz K.
Published: August 2008

Cementing deep high pressure and high temperature (HPHT) gas wells has always been a challenge. Conventional heavy weight cement systems which have been used in the past have often had to sacrifice the set cement mechanical properties such as compressive strength, permeability, and porosity, to provide a slurry design which is stable, mixable and pumpable. Utilizing an optimized High Density High Performance Slurry (HDHPS) the challenge has been successfully overcome for the HPHT in the Ghawar Reservoir in the Kingdom Of Saudi Arabia. The concept of the particle size distribution was applied to provide a cost effective solution to cementing of these HPHT wells.

The packing volume fraction was optimized for the cement blend. As a result, the slurry properties become a function of the dry blend instead of the additives in the slurry system. Particle Size Distribution optimizes both slurry and set cement properties simultaneously. The permeability and porosity of the set cement are reduced due to improved particle packing of the system. In addition, the rheological properties are improved which alleviates settling problems commonly encountered with conventional high density cement slurries.

Extensive lab testing and yard trial prior to field application demonstrated the superior performance of these slurries over conventional cements in both the liquid phase and when set.

To date, four 9 5/8" casing strings and two 7" Liners have been isolated in the Jilh formation using HDHPS technology, with cement weights above 20 ppg (2400 kg/m3). Details of the slurry technology are presented along with data documenting the jobs performed to date in Kingdom of Saudi Arabia. The system is widely accepted by Saudi Aramco and is the preferred system for critical high pressure cementing.
The Use of StageFrac New Technology to Complete and Stimulate Horizontal Wells: Field Case
Authors: Franco C. , Solares R. , Marri H. , Hussain H.
Published: August 2008

This paper summarizes the results from the deployment of a StageFrac completion and multi-stage acid fracturing treatment in the first field trial conducted in a Saudi Aramco gas producer. The main objective of the field trial was to ascertain the effectiveness of this state-of-the-art technology in properly stimulating long horizontal gas producers and be able to use it to help severely damaged or under-performing wells achieve their maximum potential. The secondary objective was to evaluate the ability to connect the main Khuff-C producing zones through hydraulic fracturing and thus ascertain the viability of this technology as a potential alternative for dual-lateral completions in certain parts of the field.

Drilling problems necessitated the reduction of the total horizontal well from the originally planned 5,000 ft. to a final length of 3,835 ft. Moreover, mechanical problems encountered while setting the StageFrac completion reduced the total horizontal length open to flow to 1,440 ft. only, leaving 2,394 ft. isolated and unable to flow. Hence, the number of fracture stages originally planned at six had to be reduced to only three, but stimulation operations were implemented trouble-free with a good number of lessons learned that will be applied in future applications of the technology. Nevertheless, the initial performance of the well compares favorably with that of two other non-stimulated horizontal gas producers with better reservoir quality and more reservoir contact, a clear indication of the successful stimulation effect achieved with the job.

This technology offers significant potential to improve the productivity of under-performing horizontal producers and help them achieve their maximum potential.
Computation of Average Well Drainage Pressure for a Parallel Reservoir Simulator
Authors: Middya Usuf , Dogru Ali H.
Published: August 2008

In history matching, simulator computed well pressures are matched against the static well pressures from the field data. In practice, many simulators use pore volume averaged grid block pressures for the perforated cells to calculate the static well pressure. While this approximation may be reasonable for large grid blocks, it certainly is not a good approximation for the smaller grid blocks. When locally refined grids around the well are used, the error becomes significant.

This paper describes a new method where the static well pressure is calculated from the approximate well drainage volume during the simulation. Drainage volume of the well is estimated from the computed fluxes. Static well pressure is then calculated by pore volume average of the dynamic grid block pressures within the drainage volume. The novelty of the method comes from the fact that fluid fluxes are computed at each iteration in a numerical reservoir simulator as part of the simulator computations. Therefore, no extra computations are needed to calculate effective drainage volume. Implementation in a parallel simulator where well blocks may cross the processor domain boundaries are handled by the new algorithm and described in the paper.

New method has been compared against the conventional method and field data. Advantages of the new method are illustrated by examples including a real field simulation.
Cyclic Production Scheme: Innovative Application in Reducing Water Production and Increasing Ultimate Recovery from Mature Areas
Authors: Al-Mutairi Saad , Al-Yousef Hasan , Al-Ajmi Fahad , Al-Hashim Hasan
Published: August 2008

Handling excessive water production is one of the most common challenges in mature oil fields. The world produces almost five barrels of water with each barrel of oil. Cyclic Production Scheme (CPS) was applied as a first field trial in the world in one of mature oil fields in Saudi Aramco to maximize ultimate oil recovery, reduce water production and enhance reservoir pressure.

The results of a conceptual simulation model that was built to assess reservoir performance under the CPS are discussed. Sensitivity cases were carried out to identify the most influential reservoir parameters on CPS. This assessment is to support the understanding and engineering interpretation behind the performeance of the CPS.
Optimization of the indole photodegradation on supported TiO2: influences of temperature, concentration, TiO2 amount and flow rate
Authors: Merabet Smail , Schneider Michel , Robert Didier , Benkhanouche Smail , Bouhelassa Mohammed , Weber Jean Victor
Published: August 2008

This work describes the photodegradation of aqueous indole solutions by using TiO2 supported on cellulose fibres. Four parameters were studied: the indole concentration; the TiO2 amount; the temperature and the flow rate. Central composite experimental design was used to determine the influences of the parameters on the indole degradation percentage. We demonstrate that in our experimental domain the quasi complete degradation of indole is in all cases reached and more interestingly that it is possible to find unique values of TiO2 amount and flow rate leading to optimised photodegradation of indole in the studied domains of temperature and indole concentration.
Electricity production and microbial biofilm characterization in cellulose-fed microbial fuel cells
Authors: Ren Z. , Steinberg L. M. , Regan J. M.
Published: August 2008

Converting biodegradable materials into electricity, microbial fuel cells (MFCs) present a promising technology for renewable energy production in specific applications. Unlike typical soluble substrates that have been used as electron donors in MFC studies, cellulose is unique because it requires a microbial consortium that can metabolize both an insoluble electron donor (cellulose) and electron acceptor (electrode). In this study, electricity generation and the microbial ecology of cellulose-fed MFCs were analyzed using a defined co-culture of Clostridium cellulolyticum and Geobacter sulfurreducens. Fluorescent in situ hybridization and quantitative PCR showed that when particulate MN301 cellulose was used as sole substrate, most Clostridium cells were found adhered to cellulose particles in suspension, while most Geobacter cells were attached to the electrode. By comparison, both bacteria resided in suspension and biofilm samples when soluble carboxymethyl cellulose was used. This distinct function-related distribution of the bacteria suggests an opportunity to optimize reactor operation by settling cellulose and decanting supernatant to extend cellulose hydrolysis and improve cellulose-electricity conversion.
Modelling of enhanced CSO treatment in secondary clarifiers with a modified Activated Sludge Model no. 3
Authors: Ahnert M. , Günther N. , Kuehn V. , Krebs P. , Svardal K. , Spatzierer G.
Published: August 2008

An alternative approach for combined water treatment as opposed to its CSO discharge into receiving water is its bypass to the inlet of secondary clarifiers (SC). To analyse the processes and to evaluate the performance of this approach, experiments and numerical modelling were carried out. In batch and pilot scale experiments major effects were identified and quantified. The Activated Sludge Model No. 3 (ASM3) was modified to simulate the batch and pilot scale experiments for implementation of the bypass-specific processes and thus to set up an overall balance of the relevant compounds. With some modifications of ASM3, good agreement of the modelling results with measurements of COD, nitrogen and phosphorus were achieved.
Modeling anaerobic digestion of dairy manure using the IWA Anaerobic Digestion Model no. 1 (ADM1)
Authors: Page D. I. , Hickey K. L. , Narula R. , Main A. L. , Grimberg S. J.
Published: August 2008

The Anaerobic Digestion Model No. 1 (ADM1) can be used to describe treatment of dairy manure once manure characteristics have been incorporated in the model. In this paper a parameter set is presented that can be used with ADM1 for simulation of dairy manure digester performance. Model results have been verified with bench-scale experiments and reported data from full-scale systems. Model predictions fit experimental data best for biogas composition and digester effluent COD. Simulated biogas productions were inconsistent with measurements from three different digesters. The model overpredicted acetogenesis, resulting in higher simulated than observed acetate concentrations. However, total volatile acid concentrations were simulated reasonably well. The model consistently predicted higher inorganic nitrogen than measured or reported results, indicating a need for further research in that area. The presented model and associated parameter set can be used to simulate and optimize the performance of full-scale dairy manure digesters.
Mutagenic fate of insecticide fenitrothion in the environment—mutagenicity increases both by anaerobic biodegradation and photodegradation
Authors: Matsushita T. , Matsui Y. , Taniwaki S. , Ikeba K.
Published: August 2008

In the present study, our objectives were (1) using the Ames assay, to evaluate the change in mutagenicity of a fenitrothion-containing solution during aerobic biodegradation, anaerobic biodegradation, and photodegradation, and (2) to identify possible mutagenic transformed products (TPs) that contributed substantially to any increase in mutagenicity. Mutagenicity of the fenitrothion-containing solution did not increase during aerobic biodegradation with any of the tested bacterial strains. In contrast, the mutagenicity increased for strain YG1029 during anaerobic biodegradation because of the generation of a strongly mutagenic TP, amino-fenitrothion. During photodegradation, mutagenicities increased slightly for YG1021 and YG1024, possibly owing to the production of a previously unreported mutagenic TP.
5-Fluorouracil: Mechanisms of Resistance and Reversal Strategies
Authors: Zhang Ning , Yin Ying , Xu Sheng-Jie , Chen Wei-Shan
Published: August 2008

The purpose of this work is to review the published studies on the mechanisms of action and resistance of 5-fluorouracil. The review is divided into three main sections: mechanisms of anti-tumor action, studies of the resistance to the drug, and procedures for the identification of new genes involved in resistance with microarray techniques. The details of the induction and reversal of the drug resistance are also described.
Flavonoids and a New Polyacetylene from Bidens parviflora Willd
Authors: Li Yu-Lan , Li Jun , Wang Nai-Li , Yao Xin-Sheng
Published: August 2008

Fifteen flavonoids, 1-7 and 9-16, and a polyacetylene, 8, were isolated from the ethanol extract of the dried whole plant of Bidens parviflora Willd. by various chromatographic techniques. Their structures have been elucidated on the basis of spectroscopic analyses and chemical studies. Compound 8 is new and was identified as 3-(R),8(E)-decene-4,6-diyne-1,3,10-triol. All the flavonoid compounds were isolated for the first time from this plant species.
Determination of Parathion and Carbaryl Pesticides in Water and Food Samples Using a Self Assembled Monolayer /Acetylcholinesterase Electrochemical Biosensor
Authors: Pedrosa Valber A. , Caetano Josiane , Machado Sergio A. S. , Bertotti Mauro
Published: August 2008

An acetylcholinesterase (AchE) based amperometric biosensor was developed by immobilisation of the enzyme onto a self assembled modified gold electrode. Cyclic voltammetric experiments performed with the SAM-AchE biosensor in phosphate buffer solutions (pH = 7.2) containing acetylthiocholine confirmed the formation of thiocholine and its electrochemical oxidation at Ep = 0.28 V vs Ag/AgCl. An indirect methodology involving the inhibition effect of parathion and carbaryl on the enzymatic reaction was developed and employed to measure both pesticides in spiked natural water and food samples without pre-treatment or pre-concentration steps. Values higher than 91-98.0% in recovery experiments indicated the feasibility of the proposed electroanalytical methodology to quantify both pesticides in water or food samples. HPLC measurements were also performed for comparison and confirmed the values measured amperometrically.
Detecting Land Subsidence in Shanghai by PS-Networking SAR Interferometry
Authors: Liu Guoxiang , Luo Xiaojun , Chen Qiang , Huang Dingfa , Ding Xiaoli
Published: August 2008

Existing studies have shown that satellite synthetic aperture radar (SAR) interferometry has two apparent drawbacks, i.e., temporal decorrelation and atmospheric contamination, in the application of deformation mapping. It is however possible to improve deformation analysis by tracking some natural or man-made objects with steady radar reflectivity, i.e., permanent scatterers (PS), in the frame of time series of SAR images acquired over the same area. For detecting land subsidence in Shanghai, China, this paper presents an attempt to explore an approach of PS-neighborhood networking SAR interferometry. With use of 26 ERS-1/2 SAR images acquired 1992 through 2002 over Shanghai, the analysis of subsiding process in time and space is performed on the basis of a strong network which is formed by connecting neighboring PSs according to a distance threshold. The linear and nonlinear subsidence, atmospheric effects as well as topographic errors can be separated effectively in this way. The subsidence velocity field in 10 years over Shanghai is also derived. It was found that the annual subsidence rates in the study area range from -2.1 to -0.6 cm/yr, and the averaged subsidence rate reaches -1.1 cm/yr.
Distributed Principal Component Analysis for Wireless Sensor Networks
Authors: Le Borgne Yann-Aël , Raybaud Sylvain , Bontempi Gianluca
Published: August 2008

The Principal Component Analysis (PCA) is a data dimensionality reduction technique well-suited for processing data from sensor networks. It can be applied to tasks like compression, event detection, and event recognition. This technique is based on a linear transform where the sensor measurements are projected on a set of principal components. When sensor measurements are correlated, a small set of principal components can explain most of the measurements variability. This allows to significantly decrease the amount of radio communication and of energy consumption. In this paper, we show that the power iteration method can be distributed in a sensor network in order to compute an approximation of the principal components. The proposed implementation relies on an aggregation service, which has recently been shown to provide a suitable framework for distributing the computation of a linear transform within a sensor network. We also extend this previous work by providing a detailed analysis of the computational, memory, and communication costs involved. A compression experiment involving real data validates the algorithm and illustrates the tradeoffs between accuracy and communication costs.
SAR Observation and Modeling of Gap Winds in the Prince William Sound of Alaska
Authors: Liu Haibo , Olsson Peter Q , Volz Karl
Published: August 2008

Alaska’s Prince William Sound (PWS) is a unique locale tending to have strong gap winds, especially in the winter season. To characterize and understand these strong surface winds, which have great impacts on the local marine and aviation activities, the surface wind retrieval from the Synthetic Aperture Radar data (SAR-wind) is combined with a numerical mesoscale model. Helped with the SAR-wind observations, the mesoscale model is used to study cases of strong winds and relatively weak winds to depict the nature of these winds, including the area of extent and possible causes of the wind regimes. The gap winds from the Wells Passage and the Valdez Arm are the most dominant gap winds in PWS. Though the Valdez Arm is north-south trending and Wells Passage is east-west oriented, gap winds often develop simultaneously in these two places when a low pressure system is present in the Northern Gulf of Alaska. These two gap winds often converge at the center of PWS and extend further out of the Sound through the Hinchinbrook Entrance. The pressure gradients imposed over these areas are the main driving forces for these gap winds. Additionally, the drainage from the upper stream glaciers and the blocking effect of the banks of the Valdez Arm probably play an important role in enhancing the gap wind.
Detection of Aspens Using High Resolution Aerial Laser Scanning Data and Digital Aerial Images
Authors: Säynäjoki Raita , Packalén Petteri , Maltamo Matti , Vehmas Mikko , Eerikäinen Kalle
Published: August 2008

The aim was to use high resolution Aerial Laser Scanning (ALS) data and aerial images to detect European aspen (Populus tremula L.) from among other deciduous trees. The field data consisted of 14 sample plots of 30 m × 30 m size located in the Koli National Park in the North Karelia, Eastern Finland. A Canopy Height Model (CHM) was interpolated from the ALS data with a pulse density of 3.86/m2, low-pass filtered using Height-Based Filtering (HBF) and binarized to create the mask needed to separate the ground pixels from the canopy pixels within individual areas. Watershed segmentation was applied to the low-pass filtered CHM in order to create preliminary canopy segments, from which the non-canopy elements were extracted to obtain the final canopy segmentation, i.e. the ground mask was analysed against the canopy mask. A manual classification of aerial images was employed to separate the canopy segments of deciduous trees from those of coniferous trees. Finally, linear discriminant analysis was applied to the correctly classified canopy segments of deciduous trees to classify them into segments belonging to aspen and those belonging to other deciduous trees. The independent variables used in the classification were obtained from the first pulse ALS point data. The accuracy of discrimination between aspen and other deciduous trees was 78.6%. The independent variables in the classification function were the proportion of vegetation hits, the standard deviation of in pulse heights, accumulated intensity at the 90th percentile and the proportion of laser points reflected at the 60th height percentile. The accuracy of classification corresponded to the validation results of earlier ALS-based studies on the classification of individual deciduous trees to tree species.
Synthesis and structure of a µ‐oxo diiron(III) complex with an N‐pyridylmethyl‐N,N‐bis(4‐methylbenzimidazol‐2‐yl)amine ligand and its catalytic property for hydrocarbon oxidation
Authors: Sun Hongfei , Wang Mei , Li Fei , Li Ping , Zhao Zhenbo , Sun Licheng
Published: August 2008

A µ‐oxo diiron(III) complex [{Fe(pbba)Cl}2(µ‐O)]Cl2 (1, pbba = N‐pyridylmethyl‐N,N‐bis(4‐methylbenzimidazol‐2‐yl)amine) bearing multi‐imidazolyl motifs was synthesized and characterized by X‐ray crystallography to closely mimic the structural features of methane monooxygenase. As shown by its X‐ray crystal structure, complex 1 is a centrosymmetric dimer with an FeOFe angle of 180° , and pseudo‐octahedral around each iron(III) center. The catalytic ability of title compound in the oxidation of alkane and alkene is investigated by employing tert‐butylhydroperoxide and m‐chloroperbenzoic acid as oxidants under mild conditions. The catalytic oxidation results showed that radical intermediate dominates the oxidation process. Copyright © 2008 John Wiley & Sons, Ltd.
An optimal effective controller for discrete event systems
Authors: Chen Yi‐Liang , Lin Feng
Published: August 2008

An approach to the online synthesis of an optimal effective controller for discrete event systems is presented. The optimal effective controller can achieve the prescribed (cumulative) effectiveness measure while minimizing the total cost incurred for the execution of events. This approach is constructed over a generalized control framework for automata‐based discrete event systems, which allows event enforcement in addition to the (original) event disablement/enablement as the control mechanism. The optimal effective control policy generated by this approach is proved to be the least restrictive among all the possible optimal effective control policies for the given online expansion tree of the system behavior. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Chaotic synchronization in the presence of disturbances based on an orthogonal function neural network
Authors: Wang Hongwei , Gu Hong
Published: August 2008

Chaos synchronization problems are addressed in this paper. For chaotic synchronization systems with uncertainties and external disturbances, an orthogonal function neural network is used to achieve the synchronization of chaotic systems. Legendre orthogonal polynomials are selected as the basis functions of the orthogonal function neural network. An adaptive learning law is derived to guarantee that the tracking errors are bounded using Lyapunov stability theory. Simulation results show the efficiency of the proposed scheme. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A coordinating approach for the solution of discrete linear servo‐mechanism problems with constraints
Authors: Hassan Mohamed F. , Ali Awatef K.
Published: August 2008

A discrete‐time linear servo‐mechanism problem with system constraints is considered. An approach is developed to solve such a problem using an idea borrowed from large‐scale systems theory, in which a coordinating variable is introduced and used to satisfy state constraints. Under the assumption that the system is stabilizable and has a feasible solution, it is shown that the proposed procedure leads to the optimal solution while satisfying system constraints. A convergence analysis of the algorithm is undertaken and illustrative examples are provided to show the performance of the proposed algorithm. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Nonlinear Luenberger‐like observers for nonlinear MIMO systems
Authors: Mangsuli Purnaprajna R. , Rao N. J.
Published: August 2008

This paper deals with the design of observers for a class of continuous time nonlinear multi‐input multi‐output systems with nonlinear outputs. Geometric tools are used to transform the original system into an appropriate observer canonical form. Furthermore, a pole placement technique is used to obtain a desired transient response of resulting error dynamics. The observer design is presented for two cases. In both cases, it is shown that the observer gain can be obtained from the solution of a Riccati equation. An illustrative example of state estimation in induction motors is presented to explain the proposed observer design. The performance of the method is also verified by numerical simulations. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society