bluuebunny/crossref_metadata_2025 huggingface dataset:
Associations of resistin with inflammatory and fibrinolytic markers, insulin resistance, and metabolic syndrome in middle-aged and older Chinese
Authors: Qi Qibin , Wang Jing , Li Huaixing , Yu Zhijie , Ye Xingwang , Hu Frank B , Franco Oscar H , Pan An , Liu Yong , Lin Xu
Published: August 2008

Objective

Resistin increases insulin resistance (IR) in mice. However, the role of resistin in human disease remains controversial. We aimed to assess plasma resistin levels and their associations with inflammatory and fibrinolytic markers, IR and metabolic syndrome (MetS) among Chinese.

Design and methods

Plasma resistin was measured in a population-based cross-sectional survey of 3193 Chinese aged from 50 to 70 years in Beijing and Shanghai.

Results

The median resistin concentration was 8.60 ng/ml (interquartile range, 5.78–14.00) among all participants, and it was higher in women than in men (P=0.008). Resistin was correlated weakly with body mass index, waist circumference, high-density lipoprotein (HDL) cholesterol (negatively), homeostatic model assessment of IR and tumor necrosis factor-α receptor 2 (TNFR2; r=0.04, 0.07, –0.09 and 0.06 respectively, all P<0.05), and more highly with C-reactive protein (CRP), interleukin (IL)6 and plasminogen activator inhibitor (PAI)1 (r=0.12, 0.12 and 0.21 respectively, all P<0.001), but only HDL cholesterol, CRP, IL6, TNFR2, and PAI1 remained significantly associated with resistin in multiple regression analysis (all P<0.05). Furthermore, elevated resistin levels were associated with the higher prevalence of IR and MetS. However, the significant relationships disappeared after adjustment for inflammatory and fibrinolytic markers especially PAI1.

Conclusions

This study suggests that resistin is more strongly associated with inflammatory and fibrinolytic markers than with obesity or IR status. The associations of resistin with IR and MetS could largely be explained by inflammatory and fibrinolytic markers especially PAI1 levels.
Adhesion of nanostructured diamond film on a copper–beryllium alloy
Authors: Catledge Shane A. , Vohra Yogesh K. , Jackson Damon D. , Weir Samuel T.
Published: August 2008

Microwave plasma chemical vapor deposition (CVD) was used to coat nanostructured diamond onto a copper–beryllium alloy (∼1.7 wt% Be) commonly used as a nonmagnetic gasket material in diamond anvil cell devices. The coating is expected to be useful in preventing plastic flow of Cu–Be gaskets in diamond anvil cell devices, thus allowing for increased sample volume at high pressures and leading to improved sensitivity of magnetic measurements. The coatings were characterized by Raman spectroscopy, glancing-angle x-ray diffraction, microscopy (optical, scanning electron, and atomic force), Rockwell indentation, and nanoindentation. CVD diamond deposition on pure copper substrates has historically resulted in poor coating adhesion caused by the very large thermal expansion mismatch between the substrate and coating as well as the inability of copper to form a carbide phase at the interface. While an interfacial graphite layer formed on the pure copper substrates and resulted in complete film delamination, well-adhered 12.5 μm thick nanostructured diamond coatings were produced on the copper–beryllium (Cu–Be) alloy. The nanostructured diamond coatings on Cu–Be exhibit hardness of up to 84 GPa and can withstand strains from Rockwell indentation loads up to 150 kg without delamination.
Delamination toughness of electron beam physical vapor deposition (EB-PVD) Y2O3–ZrO2 thermal barrier coatings by the pushout method: Effect of thermal cycling temperature
Authors: Tanaka M. , Liu Y.F. , Kim S.S. , Kagawa Y.
Published: August 2008

A pushout test method was used to quantify effect of thermal cycling temperatures on the delamination toughness of an electron beam physical vapor deposited thermal barrier coating (EB-PVD TBC). The delamination toughness, Γi, was related to the maximum thermal cycling temperature, Th, equal to 1000, 1025, 1050, and 1100 °C. The measured delamination toughness varied from 9 to 95 J/m2. At Th = 1000 °C, Γi attained a maximum value, larger than that of the as-deposited sample and decreasing with increased Th. During the thermal cycling tests, the thermally grown oxide (TGO) was formed between the TBC and the bond coat deposited onto the superalloy substrate. Inside the TGO layer, mixture of Al2O3 and ZrO2 oxides was observed close to the TBC side with nearly pure Al2O3 phases close to the bond-coat side. During the pushout test, delamination occurred at the interface of the mixture and pure Al2O3 layer with an exception for Th = 1100 °C specimens where delamination also occurred at the interface between the TGO and bond-coat layers. The effect of thermal cycling temperatures on the delamination toughness is discussed in terms of the microstructural change and delamination behavior.
Indentation fracture of low-dielectric constant films: Part I. Experiments and observations
Authors: Morris Dylan J. , Cook Robert F.
Published: August 2008

Advanced microelectronic interconnection structures will need dielectrics of low permittivity to reduce capacitive delays and crosstalk, but this reduction in permittivity typically necessitates an increase in the porosity of the material, which is frequently accompanied by reduced mechanical reliability. Failure by brittle fracture remains a typical manufacturing and reliability hurdle for this class of materials. Part I of this two-part work explores the instrumented indentation and indentation fracture responses of a variety of organosilicate low-dielectric constant (low-κ) films. Three different chemical varieties of low-κ material were tested. The influence of film thickness on the fracture response is also explored systematically. Correlations are made between instrumented indentation responses and differing modes of fracture. It is demonstrated that the elastic response of the composite film + substrate systems can be simply tied to the fraction of the total indentation strain energy in the film. These results are then used in the companion paper, Part II [D.J. Morris and R.F. Cook, J. Mater. Res.23, 2443 (2008)], to derive and use a fracture mechanics model to measure fracture properties of low-κ films.
Polyaniline nanofibers prepared by a facile electrochemical approach and their supercapacitor performance
Authors: Zhang Haibin , Li Hanlu , Zhang Fengbao , Wang Jixiao , Wang Zhi , Wang Shichang
Published: August 2008

Polyaniline (PANI) nanofibers were prepared electrochemically by a template-free method on different active substrates in aqueous solutions containing aniline and inorganic acid or organic acid. The influences of experimental parameters, such as polymerization potential, techniques of applied potential, electrolyte composition, and polymerization temperature, on the morphologies of the PANI nanofibers were systematically investigated. The PANI nanofibers obtained have promising applications in supercapacitors whose specific capacitance is as high as 1.21 × 103 F/g, which is the highest value possible using sulfuric acid (1.00 M H2SO4) as electrolyte. In addition, the formation mechanism of PANI nanofibers is discussed.
Fabrication of titanium-based microstructured surfaces and study on their superhydrophobic stability
Authors: Li Baojia , Zhou Ming , Yuan Run , Cai Lan
Published: August 2008

Based on the classical wetting theories, two theoretically predicted formulas of the apparent contact angles on square-pillar-array microstructured surfaces for Wenzel mode and Cassie mode have been derived, respectively. The theories of superhydrophobic stability on microstructured surfaces have been summarized. Four square-pillar-array samples were fabricated on titanium substrates by using the femtosecond laser micromachining technology, and wettability was analyzed by both experimental and analytical methods. The results showed that the titanium-based surfaces are superhydrophobic. The maximal apparent contact angle is up to 156.9°, while the corresponding sliding angle is 4.7°. Testing of the superhydrophobic stability of the surfaces showed that the maximal deviation of the apparent contact angles is only 0.6°. Analyses indicate that the stable superhydrophobicity of the supplied titanium-based surfaces is within a certain range and not perfect. To improve that, a practical controllable method is proposed herein for the design of a stable superhydrophobic surface.
Evaluation of true interlamellar spacing from microstructural observations
Authors: Ikeda Teruyuki , Ravi Vilupanur A. , Snyder G. Jeffrey
Published: August 2008

A method for evaluating true interlamellar spacing from micrographs is proposed for a multidomained lamellar structure. The microstructure of these materials is assumed to be composed of many domains with the lamellae aligned roughly parallel to each other within each domain and with the domains themselves randomly oriented relative to one another. An explicit expression for the distribution of apparent interlamellar spacing is derived assuming that the distribution of the true interlamellar spacing is Gaussian. The average interlamellar spacing is close to the peak interlamellar spacing observed in the distribution. The theoretical distributions are compared with experimental ones obtained by analyzing micrographs of PbTe–Sb2Te3 lamellar composites.
Preparation of Zr60Ni21Al19 bulk metallic glass and compression behavior under high pressure
Authors: Li G. , Jing Q. , Xu T. , Huang L. , Liu R.P. , Liu J.
Published: August 2008

Zr60Ni21Al19 metallic glass rod, with a diameter of 8 mm, is manufactured by copper mold casting. The as-cast bulk metallic glass (BMG) exhibits nearly zero plastic strain, but a high strength of 1.88 GPa. The compression behavior of this new zirconium-base ternary BMG under high pressure at ambient temperature in a diamond-anvil cell instrument has been unraveled using energy dispersive x-ray diffraction with a synchrotron radiation source. The investigation shows that the amorphous structure of Zr60Ni21Al19 is stable under pressures up to 24.5 GPa at room temperature. According to the Bridgman equation of state, the bulk modulus B0 = 96 GPa has been obtained.
Electronic structure and chemical bonding of α- and β-Ta4AlC3phases: Full-potential calculation
Authors: Lu Wei , Deng Xiaohui , Wang Hai , Huang Haitao , He Lianlong
Published: August 2008

First-principles total-energy and heat of formation calculations on α and β polymorphs of Ta4AlC3have been made with a full-potential electronic structure program with the generalized gradient approximation, which shows that α phase is more stable than β phase. The charge transfer and chemical bonding of the two phases were investigated quantitatively by using Bader’s quantum theory of atoms in molecules (AIM). The results show that the bonding between Ta1-C2 is stronger in α phase than β phase, which leads to the stability of α phase.
Gender-specific regulation of mitochondrial fusion and fission gene transcription and viability of cortical astrocytes by steroid hormones
Authors: Arnold Susanne , de Araújo Gilda Wright , Beyer Cordian
Published: August 2008

Astroglia and steroid hormones such as estrogen and progesterone regulate cell growth, function, and protection in the central nervous system (CNS). It appears that astrocytes and steroids act in concert to promote cell survival under pathological conditions. With respect to the role of mitochondrial fusion and fission in energy metabolism, apoptosis, and proliferation, astrocyte mitochondria resemble a perfect intracellular target for steroids to modulate these processes, thereby promoting cell vitality after damage. We have studied the effects of estrogen and progesterone on cell viability in comparison with mitochondrial fusion and fission gene transcription in primary cortical astrocytes from female and male mouse brains. Estrogen- and progesterone-treated female astrocytes demonstrated an increase in cell number and proliferation marker accompanied by an upregulation of fusion and fission gene transcription, which were apparently balancing pro- and anti-apoptotic processes. On the other hand, male astrocytes exhibited no change in cell number after estrogen treatment, but a decrease after progesterone administration. This could be the consequence of stimulated apoptosis in male astrocytes by both steroids, which was counterbalanced by an increased proliferation in the presence of estrogen, whereas it was strengthened in the presence of progesterone. Supportively, estrogen promoted and progesterone decreased the transcription of fusion and fission genes. We suggest that estrogen and progesterone affect mitochondrial fusion and fission gene transcription in cortical astrocytes in a gender-specific way, thereby influencing mitochondrial function differently in both genders. Thus, interaction of sex steroids with mitochondria may represent one possible cause for gender differences in cellular pathology in the CNS.
Functional expression of CXCR4 in somatotrophs: CXCL12 activates GH gene, GH production and secretion, and cellular proliferation
Authors: Lee Yongho , Kim Jeong Mo , Lee Eun Jig
Published: August 2008

The interaction of chemokine (C-X-C motif) ligand 12 (CXCL12) and its receptor CXCR4 may play an important role in the regulation of anterior pituitary function. In this study, we investigated the expression of CXCL12 and CXCR4 and their role in normal rat pituitary and GH-producing GH3 tumor cell line. RT-PCR analysis and immunohistochemistry revealed that CXCR4 was expressed in normal rat anterior pituitary and GH3 tumor cells. Double immunofluorescent staining showed the complete colocalization of CXCR4 with GH in rat pituitary, indicating that CXCR4 is specifically expressed in rat somatotrophs. Using rat primary pituitary cell cultures and GH releasing hormone receptor expressing stable GH3 cells (GH3-GHRHR), we evaluated the function of CXCL12 compared with GHRH. CXCL12 stimulated GH gene activation in both primary rat anterior pituitary cells and GH3-GHRHR cells. CXCL12 also stimulated GH secretion from primary rat pituitary cells in a dose-dependant manner. BrdU incorporation was increased in response to CXCL12 addition in GH3 cell culture, indicating CXCL12-induced cell proliferation. CXCL12-dependent phosphorylation of ERK1/2 was also confirmed by western blot analysis, supporting the evidence that MAPK is an intracellular mediator of CXCL12/CXCR4 interaction in GH3 cell proliferation. In conclusion, these results indicate that CXCL12/CXCR4 interaction plays an important role in GH production, secretion, and the proliferation of somatotrophs.
Collaboration Breeds Success in the Khurais Mega-Project in Saudi Arabia
Authors: Al-Ghamdi Ali , Tello Roberto , Al-Bani Fahad , Swadi Mohammad
Published: August 2008

The Khurais project, located in the central part of Saudi Arabia near Riyadh, is the largest project in Saudi Arabia. Comprising drilling and completion of 168 horizontal producer wells at 12,000 ft measured depth (MD) each, one of the success measures of this project revolves around its expeditious completion. With the focus on this objective, a collaborative effort was implemented to analyze and assess the drilling challenges, how best to address them, and to apply the lessons learned throughout the duration of the project. This collaboration included service companies, drilling engineers and rig foremen coupled with an on-site bit design engineer. As a result of this teamwork, improvements were achieved in a short period of time, providing the confidence that the objective will be met. One of the primary objectives was to produce a drill bit that would provide the highest rate of penetration (ROP) possible without compromising steerability. The 12¼-in. hole section of the wells is particularly demanding, with a build section from 0° to 87° through interbedded formations. Achieving a desired buildup rate with good ROP can be negated by a bit that may be too aggressive and that has poor directional control.

Through the group effort, the team was able to develop an optimized 12¼-in. polycrystalline diamond compact (PDC) bit that resulted in a ROP increase by over 40% since the project’s onset, in only three months. With the ultimate goal of increasing ROP more than 50%, the new bit design is proving to be a definitive solution. The authors will describe the process and design analyses that were used to develop the PDC bit design for the application, from the collaboration to the use of post-design/parameter analysis after the run. They will also illustrate the importance of post-action reviews of lessons learned to apply the correct operating practices, the desired bottom-hole assembly (BHA), and bit design in the achievement of record ROPs.
Improved Wellbore Clean Up - Successful Case Histories in Saudi Arabia from Development to Field Implementation
Authors: Bustin Baron , Phillips James , Al-Otabi Msalli , Moqbil Khalid Bin , Zeid Saleh Abou , Christian Chad F. , Torres Cristina , White Craig
Published: August 2008

An effective and efficient means to remove the filter cake and remediate the internal near wellbore damage associated with synthetic or oil-based mud (S/OBM) filtrate is required in reservoirs drilled with oil-based mud (OBM) drill-in fluid (DIF). Often traditional chemical methods using inorganic acids, organic solvents, and mutual solvents used to clean-up filter cake deposits and remove skin damage are ineffective, even with multiple treatments.

Collaborative laboratory research between the operator and a service company resulted in a treatment for removing much of the damage associated with OBM drill-in fluid. A fluid was developed to fluidize and reverse the wettability of the OBM filter cake solids, acidizing soluble particles and remediating the near wellbore skin damage caused by the drill-in fluid.

Invert emulsion drill-in fluids are commonly used to drill the dune sandstone reservoirs in Saudi Arabia because of their performance and the minimized risk of formation damage due to swelling of in-situ clays. The wells were drilled with sized calcium carbonate weighted OBM; and were open-hole completed with stand-alone screens. Well diagnostics indicated that the productivity impairment on these wells was potentially related to near wellbore damage and/or severe screen plugging, either while running the screens to bottom in solids free OBM, or induced by a mixture of formation sand and OBM filter cake adhering to the screen during draw down. After spotting the treatment in the reservoir and soaking, collected fluid samples and well production measurements indicated removal of the plugging solids from the screens and wellbore, yielding significant production improvements.

Field results and complimentary traditional laboratory methods, including return permeability data show that the effectual use of this technology will remediate skin damage and plugged screens associated with the OBM DIF, water-wet the solids, acidize the majority of acid soluble particles, and improve well productivity.
Accuracy Analysis of Water Saturation Models in Clean and Shaly Layers
Authors: Hamada G. M.
Published: August 2008

An accurate determination of oil reserve either in virgin or in developed reservoirs represents the main task of petrophysicist and reservoir engineer. Input parameters of Archie's water saturation model in clean formation or suitable shaly water saturation model must be determined as accurately as possible. Archie's parameters a, m and n are the most important parameters to be estimated affecting determination of water saturation, in addition to the empirical constants required for selected empirical shaly water saturation model in case of shaly formations.

This paper presents a new technique to determine Archie's parameters called 3-D Technique. This technique is based on the three dimension plot of three parameters; formation water resistivity, water saturation and formation porosity. A comparison study with conventional technique and CAPE technique is conducted to outline the accuracy level of each technique defining Archie's parameters a, m and n. Two field examples are given to show the applicability of three techniques and also to demonstrate the impact the uncertainty of Archie's parameters values on the accuracy of calculated water values using Archie's model or shaly water saturation model.
First High Pressure and High Temperature Digital Electric Intellitite Welded Permanent Down Hole Monitoring System for Gas Wells
Authors: Shafiq Muhammad , Al-Faraj Omar , Al-Kanaan Adnan A. , Al-Malki Bandar H.
Published: August 2008

This paper describes an innovative and reliable first High Pressure High Temperature digital electric permanent monitoring solution with state-of-the-art intellitite welded system that allows bottom hole pressure and temperature in real time in JFYN-01 gas well.

Permanent down hole system provide bottom hole pressures and temperatures during the producing life of the well both in flowing and shut in conditions which allows to optimize production and flow above dew point in deep high pressure and high temperature wells where intervention is very expensive. The down hole gauge system is connected from wellsite to gas plant through SCADA which allows to monitor well performance in real time. This data are used for history matching, deliverability and transit testing.

Included in the paper are equipment selection, design, development details, installation procedures, and "lessons learned" after installation of the fully welded digital permanent down hole monitoring system.

Using HPHT permanent system will increase recovery factor and allows producing the well at optimum rate; i.e., above dew point pressure. Ultimately, PDHMS will limit the future interventions.
Visualization of Steam Zone Advancement During Heavy Oil Recovery
Authors: Alajmi Abdullah F. , Grader Abraham , Halleck Phillip
Published: August 2008

The global demand of crude oil is increasing over time. The expansion of industries and increase of population have caused petroleum production to lag behind demand. Oil producing countries thus face a daunting challenge in continuing to meet this demand requiring development of unconventional reservoirs. One such resource is contained in heavy oil reservoirs. Producing this high viscosity oil is complex and challenging usually requiring thermal recovery techniques in which heat is introduced into the reservoir to lower the oil viscosity. However, the details of the process are poorly understood, making efficient engineering of these projects difficult. In this work, heavy oil recovery by steam flood is evaluated experimentally using X-ray computed tomography (CT). The effect of heat loss on steam zone advancement and its impact on heavy oil recovery is investigated.

The X-ray CT was used to visualize and observe experimentally the heavy oil fluid flow displacement in unconsolidated core sample. Prior to steam flood, the heavy oil saturation in the core sample was 72% and irreducible water saturation was 28%. The detail of the experimental steps were monitored and quantified by the X-ray CT facilities.

The performance of heavy oil recovery by steam flood was analyzed. Heavy oil recovery was 37.7% at breakthrough. The steam zone advancement over time was quantified. The steam condensed to hot water at the interface with heavy oil during the displacement. The steam zone, hot water bank, and heavy oil movement were monitored. Maps and profiles of oil saturation over pore volume injected were generated. The heat loss to the surrounding medium and to the displaced fluid (heavy oil) controls the steam zone advancement.
Alternative water sources and endotoxin
Authors: O'Toole J. , Sinclair M. , Jeavons T. , Leder K.
Published: August 2008

The primary objective of this preliminary study was to ascertain the concentration of endotoxin in a variety of Australian water types, including recycled water. A total of 42 sampling sites were surveyed, the majority on at least 2 separate occasions (total number of samples analysed was 76). Samples were collected from a variety of locations throughout Australia including: drinking water distribution (12), drinking water reservoir (4), wastewater treatment train (11) and finished recycled water (15). Class A recycled waters, defined microbiologically in Australian regulations as having <10 E. coli per 100 mL, where the treatment train did not include membrane filtration, gave rise to an average measured endotoxin concentration of 2.030 Endotoxin Units (EU) per mL (N=7). For recycled Class A water samples, where membrane filtration was part of the treatment train (N=3) the average endotoxin concentration was 41 EU/mL. Measured endotoxin concentrations in drinking water varied from <4 to 119 EU/mL. Results of this preliminary study indicate that endotoxin concentrations in recycled water may be reduced to levels at least as low as those found in drinking water but for some recycled waters, where membrane filtration is not practiced, higher endotoxin concentrations may persist.
Potential of in-situ sensors with ion-selective electrodes for aeration control at wastewater treatment plants
Authors: Kaelin D. , Rieger L. , Eugster J. , Rottermann K. , Bänninger C. , Siegrist H.
Published: August 2008

A pilot-scale activated sludge wastewater treatment plant (WWTP) operated with nitrification and pre-denitrification was monitored with a set of on-line sensors for over 3 years. Wet-chemistry ex-situ analyzers, UV and UV-Visible in-situ sensors and in-situ sensors based on ion-selective electrodes (ISE) were used. New ISE sensors for ammonium, nitrate and nitrite, adapted to water and wastewater matrices, have been released in recent years, With adequate quality control they proved to be highly accurate and reliable in WWTP influents and activated sludge (AS) reactors even at the end of the biological treatment zone, working at low ammonium concentrations (1–2 mgN/l). The ammonium measurement was used to test several feed-forward and feed-back aeration control strategies. The first aim was to keep inorganic nitrogen compounds, i.e. ammonium, nitrate and particularly nitrite, as low as possible in the effluent, and within Swiss national standards (<2.0 mgNH4-N/l, <0.3 mgNO2-N/l, 24 h average). All the strategies were successful at keeping ammonium low and subsequently at gaining denitrification capacity to significantly reduce the total nitrogen discharge. Some control strategies however generated temporary peaks of ammonium or even accumulation of nitrite.
Effects of different hydraulic models on predicting longitudinal profiles of reactive pollutants in activated sludge reactors
Authors: Zima P. , Makinia J. , Swinarski M. , Czerwionka K.
Published: August 2008

This paper presents effects of dispersion on predicting longitudinal ammonia concentration profiles in activated sludge bioreactor located at “Wschod” WWTP in Gdansk. The aim of this study was to use the one-dimensional advection-dispersion Equation (ADE) to simulate the flow conditions (based on the inert tracer concentrations in selected points) and longitudinal profile of reactive pollutant (based on the ammonia concentration profiles in selected points). The simulation results were compared with the predictions obtained using a traditional “tanks-in-series” (TIS) approach, commonly used in designing biological reactors. The use of dispersion coefficient calculated from an empirical formula resulted in substantial differences in the tracer concentration distributions in two sampling points in the bioreactor. Simulations using the one-dimensional ADE and TIS model, with the nitrification rate incorporated as the source term, revealed that the hydraulic model plays a minor role compared to the biochemical transformations in predicting the longitudinal ammonia concentration profiles.
Marine macroalga Sargassum horneri as biosorbent for heavy metal removal: roles of calcium in ion exchange mechanism
Authors: Southichak B. , Nakano K. , Nomura M. , Chiba N. , Nishimura O.
Published: August 2008

Brown seaweed Sargassum horneri, a troublesome biomass scattered along the seashore, was utilized as a biosorbent for Pb(II) removal from aqueous solutions. The Pb(II) adsorption by brown seaweed was enhanced by pretreatment with CaCl2, and the Langmuir adsorption isotherm equation showed a maximum capacity of a Qmax of 0.696 mmol/g and ab value of 94.33 L/mmol. Results obtained from the mass-balance equation derived from the simulation model of the Langmuir adsorption isotherm suggested that the adsorption performance of brown seaweed biosorbent was sufficient to reduce the concentration of Pb(II) to meet the range of WHO guideline. The mechanism, as elucidated using pH monitoring, adsorption rate and ion exchange model, involved the rapid pH change of metal solutions that led to high reaction rate and Pb(II) uptake in the first 30 min of the biosorption process. The energy X-ray analysis's result confirmed the sharp reduction of calcium content in the biosorbent after Pb(II) adsorption. The amount of calcium ions released from the biosorbent was about 1.5 times the amount of Pb(II) adsorbed and proved the role of calcium in the ion exchange mechanism. These adsorption equilibrium and mechanistic studies provide useful information for system design and performance prediction of biosorption processes.
The use of microcalorimetry to compare the biological activity of a CAS and a MBR sludge—application to pharmaceutical active compounds
Authors: Bouju H. , Buttiglieri G. , Malpei F.
Published: August 2008

Micropollutants removal, such as pharmaceutical substances, during wastewater treatment processes is becoming a greater issue everyday. In order to optimize it, their biodegradation processes have to be better understood. So far, microcalorimetry has been used worldwide to investigate chemical reactions. For few years now it has also been developed to model and control biological processes. In the case of micropollutants, respirometry is, most of the time, not precise enough to determine biodegradation. That is why, microcalorimetric experiments have been set up. For this purpose, a 2 L Bio-RC1 (Mettler-Toledo) has been modified to reach a resolution of 5–10 mW.L−1.

In this study, the biodegradation rate of standard substrates (Ethanol and Ammonia) by an activated sludge from a full-scale CAS and one from a MBR pilot plant operating in parallel have been compared by means of microcalorimetry. Then few trials to determine the biodegradation of selected pharmaceutical substances, as well as the eventual inhibition induced by them have been made. The first results did not exhibit any biological activity. However, they have displayed inhibition for both studied substances.
Research in International Education
Authors: Dolby Nadine , Rahman Aliya
Published: August 2008

Until recently, international education has existed at the margins of educational research. However, in the current context of globalization, international education has moved closer to the center of educational research throughout the world. In this article, the authors identify, describe, and analyze six distinct research approaches to international education: comparative and international education, internationalization of higher education, international schools, international research on teaching and teacher education, internationalization of K-12 education, and globalization of education. Within each approach, the authors discuss the historical context and the global political, economic, social, and cultural shifts that have shaped the research approach; map the major research trajectories that have developed; discuss the audience and research community; and analyze strengths and weaknesses. The authors conclude with a discussion of emergent trends within research in international education.
RNA:DNA Ratio and Other Nucleic Acid Derived Indices in Marine Ecology
Authors: Chícharo Maria Alexandra , Chícharo Luis
Published: August 2008

Some of most used indicators in marine ecology are nucleic acid-derived indices. They can be divided by target levels in three groups: 1) at the organism level as ecophysiologic indicators, indicators such as RNA:DNA ratios, DNA:dry weight and RNA:protein, 2) at the population level, indicators such as growth rate, starvation incidence or fisheries impact indicators, and 3) at the community level, indicators such as trophic interactions, exergy indices and prey identification. The nucleic acids derived indices, especially RNA:DNA ratio, have been applied with success as indicators of nutritional condition, well been and growth in marine organisms. They are also useful as indicators of natural or anthropogenic impacts in marine population and communities, such as upwelling or dredge fisheries, respectively. They can help in understanding important issues of marine ecology such as trophic interactions in marine environment, fish and invertebrate recruitment failure and biodiversity changes, without laborious work of counting, measuring and identification of small marine organisms. Besides the objective of integrate nucleic acid derived indices across levels of organization, the paper will also include a general characterization of most used nucleic acid derived indices in marine ecology and also advantages and limitations of them. We can conclude that using indicators, such RNA:DNA ratios and other nucleic acids derived indices concomitantly with organism and ecosystems measures of responses to climate change (distribution, abundance, activity, metabolic rate, survival) will allow for the development of more rigorous and realistic predictions of the effects of anthropogenic climate change on marine systems.
Muscle Contraction and Force: the Importance of an Ancillary Network, Nutrient Supply and Waste Removal
Authors: Brüggemann Dagmar A. , Risbo Jens , Pierzynowski Stefan G. , Harrison Adrian P.
Published: August 2008

Muscle contraction studies often focus solely on myofibres and the proteins known to be involved in the processes of sarcomere shortening and cross-bridge cycling, but skeletal muscle also comprises a very elaborate ancillary network of capillaries, which not only play a vital role in terms of nutrient delivery and waste product removal, but are also tethered to surrounding fibres by collagen ”wires”. This paper therefore addresses aspects of the ancillary network of skeletal muscle at both a microscopic and functional level in order to better understand its role holistically as a considerable contributor to force transfer within muscular tissue.
The Use of Isolated Human Lymphocytes in Mycotoxin Cytotoxicity Testing
Authors: Maenetje Pholo W. , De Villiers Neil , Dutton Mike F.
Published: August 2008

The cytotoxicity of selected mycotoxins against isolated human lymphocytes was investigated, as a means of detecting mycotoxins in extracts derived from cereal samples. The methodology was based on the ability of viable cells to reduce methyl tetrazolium bromide to a purple formazan dye that could be quantitated by spectrophometric means and hence give a measure of the cytotoxicity of added substances. The results showed that there was good correlation with the occurrence of identified mycotoxins with only a minimum of false positives. For example, of the 13 samples of barley or barley derivatives that were positive for the mycotoxins, fumonisin B1 (FB1) deoxynivalenol (DON) and ochratoxin A (OTA), all gave positive cytotoxicity responses. Two samples negative for mycotoxins gave no cytotoxicity responses. There was little variation between the results for lymphocytes drawn from the same healthy volunteer on three different occasions. Furthermore, for two of the mycotoxins tested (FB1 and DON) it was possible to correlate general levels of mycotoxins present to the cytotoxic response of the lymphocytes but not for OTA, where it was concluded that interfering substances prevented direct correlation. It was concluded that this method was suited for general application as it could handle relatively high number of samples in a short period of time.
Phosphorescent Organic Light-Emitting Devices: Working Principle and Iridium Based Emitter Materials
Authors: Kappaun Stefan , Slugovc Christian , List Emil J. W.
Published: August 2008

Even though organic light-emitting device (OLED) technology has evolved to a point where it is now an important competitor to liquid crystal displays (LCDs), further scientific efforts devoted to the design, engineering and fabrication of OLEDs are required for complete commercialization of this technology. Along these lines, the present work reviews the essentials of OLED technology putting special focus on the general working principle of single and multilayer OLEDs, fluorescent and phosphorescent emitter materials as well as transfer processes in host materials doped with phosphorescent dyes. Moreover, as a prototypical example of phosphorescent emitter materials, a brief discussion of homo- and heteroleptic iridium(III) complexes is enclosed concentrating on their synthesis, photophysical properties and approaches for realizing iridium based phosphorescent polymers.
The Metal-Dependent Regulators FurA and FurB from Mycobacterium Tuberculosis
Authors: Lucarelli Debora , Vasil Michael L. , Meyer-Klaucke Wolfram , Pohl Ehmke
Published: August 2008

The ferric uptake regulators (Fur) form a large family of bacterial metalactivated DNA-binding proteins that control a diverse set of genes at the transcriptional level. Mycobacterium tuberculosis, the causative agent of tuberculosis, expresses two members of the Fur family, designated FurA and FurB. Although both belong to the same family, they share only approximately 25% sequence identity and as a consequence, they differ significantly in some of their key biological functions. FurA appears to be a specialized iron-dependent regulator that controls the katG gene, which encodes for a catalase-peroxidase involved in the response of M. tuberculosis to oxidative stress. KatG is also the key mycobacterial enzyme responsible for the activation of the first-line tuberculosis drug Isoniazid. FurB in contrast requires Zn2+ rather than Fe2+, to bind to its target sequence in regulated genes, which include those involved in Zn2+-homeostasis. Recent biochemical, crystallographic and spectroscopic data have now shed light on the activation and metal discrimination mechanisms in this protein family.
4-Azatricyclo[5.2.2.02,6]undecane-3,5,8-triones as Potential Pharmacological Agents
Authors: Kossakowski Jerzy , Bielenica Anna , Mirosław Barbara , Kozioł Anna E. , Dybała Izabela , Struga Marta
Published: August 2008

A series of twenty six arylpiperazine and aminoalkanol derivatives of 4-azatricyclo[ 5.2.2.02,6]undecane-3,5,8-trione have been prepared. The synthesized compounds were evaluated for their cytotoxicity and anti-HIV-1 activity in MT-4 cells.
Composition and Applications of Aloe vera Leaf Gel
Authors: Hamman Josias H.
Published: August 2008

Many of the health benefits associated with Aloe vera have been attributed to the polysaccharides contained in the gel of the leaves. These biological activities include promotion of wound healing, antifungal activity, hypoglycemic or antidiabetic effects antiinflammatory, anticancer, immunomodulatory and gastroprotective properties. While the known biological activities of A. vera will be briefly discussed, it is the aim of this review to further highlight recently discovered effects and applications of the leaf gel. These effects include the potential of whole leaf or inner fillet gel liquid preparations of A. vera to enhance the intestinal absorption and bioavailability of co-administered compounds as well as enhancement of skin permeation. In addition, important pharmaceutical applications such as the use of the dried A. vera gel powder as an excipient in sustained release pharmaceutical dosage forms will be outlined.
Statistical Assessment of Solvent Mixture Models Used for Separation of Biological Active Compounds
Authors: Bolboacă Sorana D. , Pică Elena M. , Cimpoiu Claudia V. , Jäntschi Lorentz
Published: August 2008

Two mathematical models with seven and six parameters have been created for use as methods for identification of the optimum mobile phase in chromatographic separations. A series of chromatographic response functions were proposed and implemented in order to assess and validate the models. The assessment was performed on a set of androstane isomers. Pearson, Spearman, Kendall tau-a,b,c and Goodman-Kruskal correlation coefficients were used in order to identify and to quantify the link and its nature (quantitative, categorical, semi-quantitative, both quantitative and categorical) between experimental values and the values estimated by the mathematical models. The study revealed that the six parameter model is valid and reliable for five chromatographic response factors (retardation factor, retardation factor ordered ascending by the chromatographic peak, resolution of pairs of compound, resolution matrix of successive chromatographic peaks, and quality factor). Furthermore, the model could be used as an instrument in analysis of the quality of experimental data. The results obtained by applying the model with six parameters for deviations of rank sums suggest that the data of the experiment no. 8 are questionable.
New Triterpene Diglycosides from the Rhizome of Cimifuga foetida
Authors: Sun Lirong , Yan Jian , Nian Yin , Zhou Lin , Zhang Hongjie , Qiu Minghua
Published: August 2008

Five new 9,19-cycloartane triterpene diglycosides, which have been named cimiaceroside C (1), and cimifosides A-D (2-5) together with the known compounds cimiracemoside D (6), cimidahurine (7) and α-D-glucopyranosyl-l-β-D-fructofuranoside (8) were isolated from the rhizome of Cimicifuga foetida. The new triterpene diglycosides 1-5 were identified as cimiacerol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 12β-hydroxycimigenol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 25-Oacetylcimig- enol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside, 24- acetylhydroshengmanol-3-O-β-D-xylopyranosyl-(1''→3')-β-D-xylopyranoside and 26- deoxyacetylacteol-3-O-β-D-xylo- pyranosyl-(1''→3')-β-D-xylopyranoside, respectively, based on analysis of their spectral data and chemical reactions.
Application of Metabolic Engineering to the Production of Scopolamine
Authors: Palazón Javier , Navarro-Ocaña Arturo , Hernandez-Vazquez Liliana , Mirjalili Mohammad Hossein
Published: August 2008

Scopolamine is an alkaloid widely used in medicine for its anticholinergic activity. The aim of this review is to show that metabolic engineering techniques constitute a suitable tool to improve the production of tropane alkaloids, focusing in particular on scopolamine. We present an overview of results obtained by various research groups, including our own, who have studied the overexpression of genes involved in the biosynthesis of scopolamine in different plant species that produce tropane alkaloids. Experiments carried out to improve production in hairy root cultures will also be described, as well as those attempting to biotransform hyoscyamine into scopolamine in roots and transgenic tobacco cells.
Evaluation of the Chemical Composition of Brazilian Commercial Cymbopogon citratus (D.C.) Stapf Samples
Authors: Barbosa Luiz Cláudio Almeida , Pereira Ulisses Alves , Martinazzo Ana Paula , Maltha Célia Regina Álvares , Teixeira Róbson Ricardo , Melo Evandro de Castro
Published: August 2008

The concentration and the chemical composition of the essential oils obtained from different samples of Cymbopogon citratus were evaluated. Among the 12 samples investigated (11 dried leaf samples and fresh plant leaves), seven presented essential oil concentrations within the threshold established by the Brazilian legislation. The moisture content was also determined and the majority of the samples presented humidity contents near 12%. The GC and GC/MS analyses of the essential oils led to identification of 22 compounds, with neral and geranial as the two major components. The total percentage of these two compounds varied within the investigated sample oils from 40.7% to 75.4%. In addition, a considerable variation in the chemical composition of the analyzed samples was observed. The process of grinding the leaves significantly decreased (by up to 68%) the essential oil content, as well as the percentage of myrcene in the oils.
Rigorous Biogenetic Network for a Group of Indole Alkaloids Derived from Strictosidine
Authors: Szabó László F.
Published: August 2008

Strictosidine, the precursor of more than 2,500 indole alkaloids, was isolated from four species of three plant families. By searching the Dictionary of Natural Products on DVD it was found that about 150 indole alkaloids were obtained from the same species (coalkaloids), which is a direct proof of their common origin. On the base of their threedimensional structure, taxonomic properties and standard reaction mechanisms an extended network was established which involved the four fundamental skeletons, the three types of carbon framework in the secologanin subunit and all major groups of indole alkaloids derived from secologanin and tryptamine (except a few minor groups, in which only less then 10 alkaloids were known). The system was extended to the heterodimer indole alkaloids and the quinoindole alkaloids as well.
Single Photon Avalanche Diodes: Towards the Large Bidimensional Arrays
Authors: Privitera Simona , Tudisco Salvatore , Lanzanò Luca , Musumeci Francesco , Pluchino Alessandro , Scordino Agata , Campisi Angelo , Cosentino Luigi , Finocchiaro Paolo , Condorelli Giovanni , Mazzillo Massimo , Lombardo Salvo , Sciacca Emilio
Published: August 2008

Single photon detection is one of the most challenging goals of photonics. In recent years, the study of ultra-fast and/or low-intensity phenomena has received renewed attention from the academic and industrial communities. Intense research activity has been focused on bio-imaging applications, bio-luminescence, bio-scattering methods, and, more in general, on several applications requiring high speed operation and high timing resolution. In this paper we present design and characterization of bi-dimensional arrays of a next generation of single photon avalanche diodes (SPADs). Single photon sensitivity, dark noise, afterpulsing and timing resolution of the single SPAD have been examined in several experimental conditions. Moreover, the effects arising from their integration and the readout mode have also been deeply investigated.
Estimation of Tree Size Diversity Using Object Oriented Texture Analysis and Aster Imagery
Authors: Ozdemir Ibrahim , Norton David , Ozkan Ulas , Mert Ahmet , Senturk Ozdemir
Published: August 2008

This study investigates the potential of object-based texture parameters extracted from 15m spatial resolution ASTER imagery for estimating tree size diversity in a Mediterranean forested landscape in Turkey. Tree size diversity based on tree basal area was determined using the Shannon index and Gini Coefficient at the sampling plot level. Image texture parameters were calculated based on the grey level co-occurrence matrix (GLCM) for various image segmentation levels. Analyses of relationships between tree size diversity and texture parameters found that relationships between the Gini Coefficient and the GLCM values were the most statistically significant, with the highest correlation (r=0.69) being with GLCM Homogeneity values. In contrast, Shannon Index values were weakly correlated with image derived texture parameters. The results suggest that 15m resolution Aster imagery has considerable potential in estimating tree size diversity based on the Gini Coefficient for heterogeneous Mediterranean forests.