bluuebunny/crossref_metadata_2025 huggingface dataset:
Discriminating between rival biochemical network models: three approaches to optimal experiment design
Authors: Mélykúti Bence , August Elias , Papachristodoulou Antonis , El-Samad Hana
Published: April 2010

Background

The success of molecular systems biology hinges on the ability to use computational models to design predictive experiments, and ultimately unravel underlying biological mechanisms. A problem commonly encountered in the computational modelling of biological networks is that alternative, structurally different models of similar complexity fit a set of experimental data equally well. In this case, more than one molecular mechanism can explain available data. In order to rule out the incorrect mechanisms, one needs to invalidate incorrect models. At this point, new experiments maximizing the difference between the measured values of alternative models should be proposed and conducted. Such experiments should be optimally designed to produce data that are most likely to invalidate incorrect model structures.

Results

In this paper we develop methodologies for the optimal design of experiments with the aim of discriminating between different mathematical models of the same biological system. The first approach determines the 'best' initial condition that maximizes the L
2 (energy) distance between the outputs of the rival models. In the second approach, we maximize the L
2-distance of the outputs by designing the optimal external stimulus (input) profile of unit L
2-norm. Our third method uses optimized structural changes (corresponding, for example, to parameter value changes reflecting gene knock-outs) to achieve the same goal. The numerical implementation of each method is considered in an example, signal processing in starving Dictyostelium amœbæ.

Conclusions

Model-based design of experiments improves both the reliability and the efficiency of biochemical network model discrimination. This opens the way to model invalidation, which can be used to perfect our understanding of biochemical networks. Our general problem formulation together with the three proposed experiment design methods give the practitioner new tools for a systems biology approach to experiment design.
Control of disseminated intravascular coagulation in Klippel-Trenaunay-Weber syndrome using enoxaparin and recombinant activated factor VIIa: a case report
Authors: Beier Ulf H , Schmidt Mary Lou , Hast Howard , Kecskes Susan , Valentino Leonard A
Published: April 2010

Introduction

Vascular malformation is associated with coagulopathies, especially when hemostasis is challenged.

Case presentation

We present the case of an 11-year-old Hispanic girl with Klippel-Trenaunay-Weber syndrome that developed disseminated intravascular coagulation after minor surgery, which was controlled by blood product transfusions and enoxaparin to address an ongoing consumptive coagulopathy. The patient, however, developed bacteremia and liver trauma that resulted in severe bleeding. To the best of our knowledge, we report here the first known instance of administering recombinant coagulation factor VIIa to control acute bleeding in a patient with Klippel-Trenaunay-Weber syndrome.

Conclusions

This case illustrates the concept of enoxaparin maintenance to suppress an ongoing consumptive coagulopathy and the use of recombinant coagulation factor VIIa to control its potentially fatal severe bleeding episodes.
Olf1/EBF associated zinc finger protein interfered with antinuclear antibody production in patients with systemic lupus erythematosus
Authors: Feng Xuebing , Li Rongliang , Huang Jing , Zhang Huayong , Zhu Lina , Hua Bingzhu , Tsao Betty P , Sun Lingyun
Published: April 2010

Introduction

The aim of the study was to determine whether Olf1/EBF associated zinc finger protein (OAZ), a transcription factor encoded by a positional systemic lupus erythematosus (SLE) candidate gene, plays a functional role in the pathogenesis in SLE.

Methods

Gene expression levels in peripheral blood cells (PBLs) measured using quantitative real-time polymerase chain reaction (qPCR) were assessed for association with disease activity and the presence of specific autoantibodies. Peripheral blood mononuclear cells (PBMCs) were incubated with specific siRNAs for three days, then cells were harvested for measuring mRNA levels using qPCR, and supernatants for levels of total immunoglobulin (Ig)G and IgM as well as secreted cytokines, chemokine and antinuclear antibodies (ANA) using ELISA. Indirect immunofluorescence was also applied for ANA detection.

Results

OAZ gene expressions in PBLs from 40 ANA-positive SLE patients were significantly increased than those from 30 normal controls (P < 0.0001) and 18 patients with rheumatoid arthritis (P < 0.01). In SLE patients, OAZ transcripts were positively correlated with SLE disease activity index (SLEDAI) score (r = 0.72, P < 0.0001) and higher in those positive for anti-dsDNA or anti-Sm antibodies (both P < 0.05). Co-culturing with OAZ siRNAs reduced mRNA levels of OAZ by 74.6 ± 6.4% as compared to those co-cultured with non-targeting siRNA and OAZ silencing resulted in reduced total IgG, ANA, interferon (IFN)-γ, interleukin (IL)-10, IL-12 and IL-21, but elevated CCL2 levels in culture supernatants (P < 0.05). The declined ANA levels correlated with inhibited OAZ expression (r = 0.88, P = 0.05), reduced IL-21 levels (r = 0.99, P < 0.01), and elevated chemokine (C-C motif) ligand 2 levels (r = -0.98, P < 0.01). Expressions of ID1-3 were significantly down-regulated by 68.7%, 70.2% and 67.7% respectively after OAZ silence, while ID3 was also highly expressed in SLE PBLs (P < 0.0001) and associated with disease activity (r = 0.76, P < 0.0001) as well as anti-dsDNA or anti-Sm antibodies (both P < 0.05).

Conclusions

Elevated expression of OAZ transcripts in SLE PBLs were strongly correlated with disease activity. Suppression of OAZ expression inhibited downstream ID levels, and secretion of ANA and IL-21, implicating a role of OAZ pathway in the pathogenesis of SLE.
Attenuation of fibrosis in vitro and in vivo with SPARC siRNA
Authors: Wang Jiu-Cun , Lai Syeling , Guo Xinjian , Zhang Xuefeng , de Crombrugghe Benoit , Sonnylal Sonali , Arnett Frank C , Zhou Xiaodong
Published: April 2010

Introduction

SPARC is a matricellular protein, which, along with other extracellular matrix components including collagens, is commonly over-expressed in fibrotic diseases. The purpose of this study was to examine whether inhibition of SPARC can regulate collagen expression in vitro and in vivo, and subsequently attenuate fibrotic stimulation by bleomycin in mouse skin and lungs.

Methods

In in vitro studies, skin fibroblasts obtained from a Tgfbr1 knock-in mouse (TBR1CA; Cre-ER) were transfected with SPARC siRNA. Gene and protein expressions of the Col1a2 and the Ctgf were examined by real-time RT-PCR and Western blotting, respectively. In in vivo studies, C57BL/6 mice were induced for skin and lung fibrosis by bleomycin and followed by SPARC siRNA treatment through subcutaneous injection and intratracheal instillation, respectively. The pathological changes of skin and lungs were assessed by hematoxylin and eosin and Masson's trichrome stains. The expression changes of collagen in the tissues were assessed by real-time RT-PCR and non-crosslinked fibrillar collagen content assays.

Results

SPARC siRNA significantly reduced gene and protein expression of collagen type 1 in fibroblasts obtained from the TBR1CA; Cre-ER mouse that was induced for constitutively active TGF-β receptor I. Skin and lung fibrosis induced by bleomycin was markedly reduced by treatment with SPARC siRNA. The anti-fibrotic effect of SPARC siRNA in vivo was accompanied by an inhibition of Ctgf expression in these same tissues.

Conclusions

Specific inhibition of SPARC effectively reduced fibrotic changes in vitro and in vivo. SPARC inhibition may represent a potential therapeutic approach to fibrotic diseases.
Selection and reliability of internal reference genes for quantitative PCR verification of transcriptomics during the differentiation process of porcine adult mesenchymal stem cells
Authors: Monaco Elisa , Bionaz Massimo , de Lima Alecsandra Sobreira , Hurley Walter L , Loor Juan J , Wheeler Matthew B
Published: April 2010

Introduction

The objective of this study was to find highly reliable internal-control genes (ICGs) for normalization of qPCR data from porcine adult mesenchymal stem cells induced to differentiate toward adipogenic and osteogenic lineages.

Methods

Stem cells were acquired from subcutaneous back fat and bone marrow of three castrated Yorkshire crossbred male pigs. Adipose and bone marrow-derived stem cells (ADSCs and BMSCs) were cultured in vitro with specific osteogenic or adipogenic differentiation medium for 4 weeks. Total RNA was extract for microarray (13,000 oligonucleotides) and qPCR analyses. Microarray data were used to uncover the most stably expressed genes (that is, potential ICGs). Co-regulation among potential ICGs was evaluated with Ingenuity Pathway Analysis. qPCR was performed on the non-coregulated ICGs candidates and on specific osteogenic (COL1A1) and adipogenic (DBI) genes. geNorm was used to uncover the most reliable ICGs by using qPCR data and the optimal number of ICGs to be used to calculate the normalization factor.

Results

Microarray data analysis revealed 27 potential ICGs. Among those, 10 genes without known co-regulation were selected to perform qPCR. geNorm performed on qPCR data uncovered high stability in expression ratio among the selected ICGs. However, especially reliable normalization was obtained by geometric mean of NSUN5, TIMM17B, and VPS4A. The effect of normalization, assessed on specific osteogenic (COL1A1) and adipogenic (DBI) genes, was apparent for the adipogenic and less apparent for the osteogenic differentiation.

Conclusions

The combination of microarray data and pairwise gene analysis allowed identification of novel and highly reliable ICGs for qPCR data normalization of adult porcine stem cells induced to differentiate to adipogenic and osteogenic lineages.
Overburden dependent AVA inversion
Authors: Skopintseva Lyubov , Stovas Alexey
Published: April 2010

Amplitude-variation-with-offset (AVO) analysis is strongly dependent on interpretation of the estimated traveltime parameters. In practice, we can estimate two or three traveltime parameters that require interpretation within the families of two- or three-parameter velocity models, respectively. Increasing the number of model parameters improves the quality of overburden description and reduces errors in AVO analysis. We have analyzed the effect of two- and three-parameter velocity model interpretation for the overburden on AVO data and have developed error estimates in the reservoir parameters.
Improved resolution in Bayesian lithology/fluid inversion from prestack seismic data and well observations: Part 2 — Real case study
Authors: Ulvmoen Marit , Omre Henning , Buland Arild
Published: April 2010

We have performed lithology/fluid inversion based on prestack seismic data and well observations from a gas reservoir offshore Norway. The prior profile Markov random field model captures horizontal continuity and vertical sequencing of the lithology/fluid variables. The prior model is also locally adjusted for spatially varying lithology/fluid proportions. The likelihood model is inferred from basic seismic theory and observations in wells. An approximate posterior model is defined, which can be simulated from by an extremely computer-efficient algorithm. The lithology/fluid inversion results are compared to manual interpretations and evaluated by cross validation in one well. Moreover, inversions based on simplified prior models are developed for comparative reasons. Both lithology/fluid realizations and predictions look geologically reasonable. The results seem to reflect general reservoir experience and information provided by the prestack seismic data and well observations. The lithology/fluid proportions appear as geologically plausible and thin elongated lithology/fluid units are identified. The study is made in a 2D cross section, but extension to a full 3D setting is feasible.
Anisotropic complex Padé hybrid finite-difference depth migration
Authors: Amazonas Daniela , Aleixo Rafael , Schleicher Jörg , Costa Jessé C.
Published: April 2010

Standard real-valued finite-difference (FD) and Fourier finite-difference (FFD) migrations cannot handle evanescent waves correctly, which can lead to numerical instabilities in the presence of strong velocity variations. A possible solution to these problems is the complex Padé approximation, which avoids problems with evanescent waves by rotating the branch cut of the complex square root. We have applied this approximation to the acoustic wave equation for vertical transversely isotropic media to derive more stable FD and hybrid FD/FFD migrations for such media. Our analysis of the dispersion relation of the new method indicates that it should provide more stable migration results with fewer artifacts and higher accuracy at steep dips. Our studies lead to the conclusion that the rotation angle of the branch cut that should yield the most stable image is 60° for FD migration, as confirmed by numerical impulse responses and work with synthetic data.
Bayesian Monte Carlo method for seismic predrill prospect assessment
Authors: Kjønsberg Heidi , Hauge Ragnar , Kolbjørnsen Odd , Buland Arild
Published: April 2010

Predrill assessment of the probability that a potential drilling spot holds hydrocarbons (HC) is of vital importance to any oil company. Of equally great value is the assessment of hydrocarbon volumes and distributions. We have developed a methodology that uses seismic data to find the probability that a vertical earth profile contains hydrocarbons and the probability distribution of hydrocarbon volumes. The method combines linearized amplitude variation with offset (AVO) inversion and stochastic rock models and predicts the joint probability distribution of the combined lithology and fluid for the entire profile. We use a Bayesian approach and find the solution of the inverse problem by Markov chain Monte Carlo simulation. The stochastic simulation benefits from a new and tailored simulation algorithm. The computational cost of finding the full joint probability distribution is relatively high and implies that the method is best suited to the investigation of a few potential drilling spots. We applied the method to a case with well control and to two locations in a prospect: one in the center and one at the outskirts. At the well location, we identify the two reservoir zones and obtain volumes that fit the log data. At the prospect, we obtain significant increases in HC probability and volume in the center, whereas there are decreases at the outskirts. Despite the large noise components in the data, the risked volumes in the center changed by a factor of three. We have designed an algorithm for computing the joint distribution of lithology, fluid, and elastic parameters for a full vertical profile. As opposed to what can be done with pointwise approaches, this allows us to calculate success probability and HC volumes.
Sensitivity of three-component 3D finite-difference elastic seismic modeling to inclusion parameters in HTI and TTI media with high inclusion density
Authors: Hu Yanrong , McMechan George
Published: April 2010

Parameters associated with the presence of inclusions (cracks or vugs) significantly influence seismic responses. The T-matrix method is used to define approximate anisotropic effective elastic stiffness tensors for media with inclusions. This allows 3D, three-component, eighth-order staggered-grid finite-difference modeling to simulate the seismic responses of anisotropic media with high inclusion density, various aspect ratios, spatial distributions and orientations of inclusions, and fluid content. The model parameters are chosen to represent aligned inclusions ranging from vertical cracks to vugs in a carbonate reservoir encased in clastics. The magnitude of anisotropy increases with increasing inclusion density for P- and S-waves. Cracks in a high-velocity carbonate reduce the stiffnesses and correspondingvelocities; this results in smaller contrasts with the surrounding (lower-stiffness) clastics and, hence, smaller reflection coefficients. S-wave splitting and the anisotropy of [Formula: see text] are clearly visible.The aspect ratio of the spatial distribution of the cracks potentially produces larger anisotropy than the crack aspect ratio, especially at large crack density. The crack distribution has little effect on stiffnesses parallel to the cracks but a large effect perpendicular to the cracks. As the crack orientation moves farther from vertical, changes in the resulting seismograms are more systematic in the direction parallel to the crack strike than perpendicular to it. The seismic signatures resulting from variations of the inclusion parameters are significant and easily visible in the data. This is a computational basis for obtaining more accurate, complete, and quantitative characterizations of inclusions.
Identification of a Novel Role for Endothelins within the Oviduct
Authors: Jeoung Myoungkun , Lee Sungeun , Hawng Hee-kyung , Cheon Yong-Pil , Jeong Youn Kyung , Gye Myung Chan , Iglarz Marc , Ko CheMyong , Bridges Phillip J.
Published: April 2010

Endothelins were first identified as potent vasoactive peptides; however, diversity in the biological function of these hormones is now evident. We have identified a novel role for endothelins: a requirement for these peptides within the oviduct during fertilization and/or early embryo development. In vivo, treatment after ovulation with a dual endothelin receptor antagonist (tezosentan) decreased the number of two-cell embryos that could be collected from within the oviducts. In vitro fertilization experiments showed that gamete viability and their ability to fertilize were not affected by treatment with this antagonist, suggesting that the effect observed in vivo was mediated by the oviduct itself. Expression of mRNA for all three isoforms of the endothelins and both receptor subtypes was detectable within the oviduct. Expression of mRNA for endothelin-3 was regulated by gonadotropins in epithelial cells of the oviduct and increased specifically within the isthmus of this structure. Immunostaining revealed localization of both endothelin receptors A and B to the columnar epithelial cells within the oviduct, suggestive of a local role for endothelins in the regulation of epithelial function and ultimately oviductal secretions. A microarray analysis revealed three likely endothelin-regulated protein networks for future analysis: the TGFβ, IL-10, and CCAAT/enhancer-binding protein superfamilies. Overall, these results suggest a novel and requisite role for endothelins within the oviduct during fertilization and/or early embryo development.
Age in Men Does Not Determine Gonadotropin-Releasing Hormone’s Dose-Dependent Stimulation of Luteinizing Hormone Secretion under an Exogenous Testosterone Clamp
Authors: Iranmanesh Ali , Mulligan Thomas , Veldhuis Johannes D.
Published: April 2010

Background: Aging is associated with a decline in incremental LH pulse amplitude, which could be due to decreased GnRH secretion or impaired GnRH action.

Hypothesis: Inconsistent published studies of GnRH action in older men may be due to disparate sex-steroid milieus.

Facility: This study was conducted at a clinical translational-research unit.

Subjects: We studied 16 healthy men (8 young men and 8 older men).

Methods: An overnight transdermal testosterone (T) clamp was implemented before randomly ordered injections of 0, 2.5, 10, 25, 250, and 750 ng GnRH on separate days (96 study sessions).

Outcomes: LH responses were quantified by variable-waveform deconvolution analysis.

Results: The T clamp maintained age-invariant mean concentrations of total, bioavailable, and free T, SHBG, LH, FSH, and prolactin. By two-way analysis of covariance, GnRH dose (P < 0.001) but not age (0.15 ≤ P ≤ 0.83) determined mean, peak, incremental, and pulsatile LH responses. Statistical power (median) was 95, 98, 90, and 99% to detect a 30% or greater age contrast at P ≤ 0.05 in mean, peak, incremental, and pulsatile LH responses, and greater than 99% to detect a 30% or greater age contrast in bioavailable or total T concentrations. Higher GnRH doses (P < 0.001) abbreviated LH secretory bursts in both age groups.

Conclusion: In the face of eugonadal concentrations of total, bioavailable, and free T, young and older men exhibit remarkably similar LH responses to a 300-fold dose range of exogenous GnRH. Accordingly, previously reported disparate effects of age on GnRH action may reflect in part age-discrepant sex-steroid milieus.
FoxG1 and TLE2 act cooperatively to regulate ventral telencephalon formation
Authors: Roth Martin , Bonev Boyan , Lindsay Jennefer , Lea Robert , Panagiotaki Niki , Houart Corinne , Papalopulu Nancy
Published: April 2010

FoxG1 is a conserved transcriptional repressor that plays a key role in the specification, proliferation and differentiation of the telencephalon, and is expressed from the earliest stages of telencephalic development through to the adult. How the interaction with co-factors might influence the multiplicity and diversity of FoxG1 function is not known. Here, we show that interaction of FoxG1 with TLE2, a Xenopus tropicalis co-repressor of the Groucho/TLE family, is crucial for regulating the early activity of FoxG1. We show that TLE2 is co-expressed with FoxG1 in the ventral telencephalon from the early neural plate stage and functionally cooperates with FoxG1 in an ectopic neurogenesis assay. FoxG1 has two potential TLE binding sites: an N-terminal eh1 motif and a C-terminal YWPMSPF motif. Although direct binding seems to be mediated by the N-terminal motif, both motifs appear important for functional synergism. In the neurogenesis assay, mutation of either motif abolishes functional cooperation of TLE2 with FoxG1, whereas in the forebrain deletion of both motifs renders FoxG1 unable to induce the ventral telencephalic marker Nkx2.1. Knocking down either FoxG1 or TLE2 disrupts the development of the ventral telencephalon, supporting the idea that endogenous TLE2 and FoxG1 work together to specify the ventral telencephalon.
Electrical Energy Prices and Losses Respect to Turkish Social-Economic Situations
Authors: Berktay Ali , Demirbas Ayhan , Kocak Saim , Nas Bilgehan
Published: April 2010

Electricity is a basic part of nature and it is one of the most widely used forms of energy. Electricity, which is a secondary energy source, can be generated from the conversion of other sources of energy, such as coal, natural gas, oil, nuclear power and renewable resources. Electricity prices have a deep impact on the competitiveness of a country's industry. Some electricity losses may occur during the process of transmission and distribution from generators to consumers. Generally there are two types of losses, one is technical losses which cover transmission losses and the other is non-technical losses including distribution losses and the incidence of illegal usage. The aim of this paper is to present the electricity usage and prices and is also to focus on the electricity losses occur both technical and non-technical means. An “electricity losses map” was produced to illustrate the electricity losses. For this purpose, a vector-based Geographic Information System (GIS) software package Arc GIS 8.3 was employed to map the data. The rate of losses within the electricity provided to the national network was about 19% in Turkey. The incidence of illegal usage and hence the rate of non-technical losses could be reduced dramatically through establishing regular action.
Current Hydropower Potential in Turkey and Sustainability of Hydropower for Turkey's Energy Demand
Authors: Balat Mustafa
Published: April 2010

With a young and growing population, low per capita electricity consumption, rapid urbanization and strong economic growth, Turkey for nearly two decades has been one of the fastest growing power markets in the world. Domestic energy consumption accounts for 37% of total energy consumption. For this reason, the renewable sources are very important for Turkey's energy sector. Projections by Turkey's Electricity Generating and Transmission Corporation (TEAS), a public company which owns and operates 15 thermal and 30 hydroelectric plants generating 91% of Turkey's electricity, indicate that rapid (as high as 10% annual) growth in electricity consumption will continue over the next 15 years. Turkey has a total gross hydropower potential of 433 GW, but only 125 GW of the total hydroelectric potential of Turkey can be economically used.
Wind Energy Potential in Turkey
Authors: Balat Havva
Published: April 2010

The aim of this paper is to investigate the wind energy potential in Turkey. In Turkey, wind energy has great potential. According to the Organization for Economic Cooperation and Development (OECD), Turkey theoretically has 160 Terra Watt hours (TWh) a year of wind potential, which is about twice as much as the current electricity consumption of Turkey. The technical potential of Turkey's wind energy is approximately 88,000 MW, its total established power is only 18.9 MW according to data for 2001. Turkey had a share of 0.11% in Europe's installed capacity in 2001. As seen in the table, the installed capacity of Turkey's wind energy has increased from 9 MW in 1998 tol9 MW in 2001. But the installed wind energy capacity is very small.
Paleozoic Carbonate Hydrocarbon Accumulation Zones in Tazhong Uplift, Tarim Basin, Western China
Authors: Lü Xiuxiang , Jiao Weiwei , Zhou Xinyuan , Li Jianjiao , Yu Hongfeng , Yang Ning
Published: April 2010

Diverse types of marine carbonate reservoirs have been discovered in the Tazhong Uplift, Tarim Basin, and late alteration of such reservoirs is obvious. The marine source rocks of the Cambrian-lower Ordovician and the middle-upper Ordovician provided abundant oil and gas for hydrocarbon accumulation. The hydrocarbons filled various reservoirs in multiple stages to form different types of reservoirs from late Caledonian to early Hercynian, from late Hercynian to early Indosininan and from late Yanshanian to Himalayan. All these events greatly complicated hydrocarbon accumulation. An analysis of the discovered carbonate reservoirs in the Tazhong Uplift indicated that the development of a reservoir was controlled by subaerial weathering and freshwater leaching, sedimentation, early diagenesis, and alteration by deep fluids. According to the origin and lateral distribution of reservoir beds, the hydrocarbon accumulation zones in the Tazhong area were identified as: karsted reservoirs, reef/bank reservoirs, dolomite interior reservoirs, and hydrothermal reservoirs. Such carbonate hydrocarbon accumulation zones are distributed mainly in specific areas of the Tazhong uplift, respectively. Because of differences in the mechanism of reservoir formation, the reservoir space, capability, type and distribution of reservoirs are often different in different carbonate hydrocarbon accumulation zones.
Low Frequency Lateral Acceleration and Subjective Ratings of Acceleration Intensity and Driving Confidence in Production Cars
Authors: Mansfield Neil J , Whiting-Lewis Elinor
Published: April 2010

There are few studies in the literature that relate subjective ratings to objective measures of low frequency lateral acceleration such as might be experienced whist cornering in a car. This paper reports a study where 1203 subjects drove two different cars (‘sport’ and ‘comfort’) on two different lateral acceleration trials. Objective measures of acceleration were taken, in addition to ratings of lateral acceleration intensity and confidence. It is shown that there was little difference between the peak lateral accelerations experienced in the two cars, although males chose to drive with greater lateral acceleration (i.e. at higher speed) than the females. Despite differences between the objective measures of acceleration being small, subjective data showed that the intensity of acceleration was rated higher for the comfort car than the sport car indicating that subjective ratings are context specific. Ratings of intensity were correlated with measures of peak acceleration for each car //// trial combination. Drivers were more confident driving the sport car than the comfort car on the two trials. However, there was only a weak and inconsistent relationship between lateral acceleration and driving confidence. It is hypothesised that this is an example of risk homeostasis whereby drivers choose to moderate their speed (and therefore the lateral acceleration) in response to their confidence level that might be affected by a complex combination of factors.
Effects of Hand-Tool Coupling Conditions on the Isolation Effectiveness of Air Bladder Anti-Vibration Gloves
Authors: Dong R.G. , McDowell T.W. , Welcome D. , Barkley J. , Warren C. , Washington B.
Published: April 2010

The goals of this study were to determine the vibration isolation effectiveness of a typical (air bladder) anti-vibration glove as a function of vibration frequency, and to investigate the effects of hand-tool coupling action and applied force level on the effectiveness. Six male volunteers were used in the study. A palm adapter method similar to that recommended in the current ISO standard for anti-vibration glove testing (ISO-10819, 1996) was used to measure the transmissibility of the glove. Three different handgrip actions (grip-only, push-only and combined grip and push), three force levels (50, 75 and 100 N), and a broad-band random spectrum were used in the experiment. This study found that the effectiveness of the glove generally increased with an increase in vibration frequency, while the glove did not provide any effective vibration isolation at frequencies less than or equal to 25 Hz. Under the same force level, the push-only action produced the greatest vibration attenuation while the grip-only action resulted in the lowest glove performance among the three actions. Increasing the force tended to increase vibration transmissibility at low frequencies (< 31.5 Hz), while transmissibility decreased at the middle frequencies (63 – 250 Hz). The knowledge generated by this study can be used to augment vibration exposure risk assessments and to promote the appropriate application of anti-vibration gloves at workplaces.
Stoneley Type Flexure Waves in Thin Elastic Plates
Authors: Andronov Ivan V.
Published: April 2010

The Stoneley type waves are known to propagate along free edges of fluid loaded elastic plates [1], [2], [3]. In the case of a plate cut by a straight line two edge waves can be possible. One is symmetric and the other is anti-symmetric in the cross-section orthogonal to the cut. It is shown in [4] that the symmetric wave exists at any frequency and for any parameters of the plate and fluid. The anti-symmetric edge wave on the contrary exists only in some frequency range.

In this paper the effects that regulate the existence or nonexistence of the anti-symmetric edge wave are analyzed and the energy characteristics of edge waves are studied.
Reduction of Micro-Pressure Wave by Active Control of Propagating Compression Wave in High Speed Train Tunnel
Authors: Matsubayashi Katsushi , Kosaka Toshifumi , Kitamura Toshiya , Yamada Shinji , Vardy Alan , Brown Jim
Published: April 2010

For the improvement of the sound environment around a portal of a high speed train tunnel, model experiments for the reduction of MPW (Micro-Pressure Wave) have been studied. In order to reduce the level of MPW, a control wave, that is a positive pressure, is generated at a side-branch in a model tunnel and is superposed on the incident wave front of a compression wave propagating through the tunnel. The method of active reduction of MPW and experimental equipment are shown. Characteristics of the wave forms of the compression wave and the control wave with suitably designed servo actuators were examined. The experimental results of the reduced level of MPW agreed well with numerical calculation results.
Low Frequency Noise and Phantom Sounds
Authors: van den Berg Frits
Published: April 2010

Suffering from more or less continuous and more or less steady low pitched sounds at home can be a serious threat to well-being. Often the sound source is not obvious or cannot be found. In many cases there is no clear evidence from the analysis of the ambient sound what the disturbing sound could be. Thus Low Frequency Noise (LFN) has become an ominous concept, a confrontation between sufferers asking for understanding and a solution and experts who are frequently helpless. From reported measurements one must conclude that at least in some cases it is improbable or even impossible that LFN is actually present at a relevant level. Although, even then, sufferers often are convinced there has to be a real, external source. A much simpler explanation may be there is not, but the sound originates within the person. When brought in a very quiet environment, normally hearing people often hear low pitched and other sounds not physically present: Phantom sounds. A hypothesis is that, when the presence of a physical sound cannot be confirmed, LFN sufferers hear low pitched phantom sounds as other people would in a dead quiet place, but do not recognize it than such. It may help sufferers to know this is a neurological phenomenon, not a psychological one. More knowledge of the sufferer about such sounds combined with the presence of more real sound at home could help to relieve the complaints.
High-Accuracy PVT Relationships for Compressed Fluids and Their Application to BET-like Modelling of CO2 and CH4 Adsorption
Authors: Milewska-Duda Janina , Duda Jan Tadeusz
Published: April 2010

This paper presents a set of high-accuracy formulae enabling the evaluation of the compression factor, activity and cohesion energy of fluids at near-critical and super-critical temperatures, with reduced molar volumes ranging from 0.4. Such data are necessary in BET-like theoretical modelling of adsorption process.

The proposed fluid state equation (PVT relationship) combines a theoretical description of the fluid entropy (based on a hard-sphere model) with cohesion energy relationships obtained via high-accuracy approximations of universal compression factor data and vapour-liquid equilibria. The resultant relationships are incorporated into a BET-like description of adsorption in materials of irregular microporous structure (LBET model).

The set of formulae gathered together in this paper allows the possible effective calculation of adsorption isotherms at near- and super-critical temperatures relative to the pore structures. A multi-variant fitting of the LBET model to the empirical data is proposed to detect active constraints for multilayer adsorption and, hence, to obtain information on the structure of the pores.

Application of the formulae to the analysis of methane and carbon dioxide adsorption onto an active carbon is discussed.
Adsorption Potential Distributions for Silicas and Organosilicas
Authors: Choma Jerzy , Jaroniec Mietek
Published: April 2010

Adsorption potential distributions (APDs) were calculated from nitrogen adsorption isotherms for macroporous silicas, and for disordered and ordered mesoporous silicas without and with organic groups attached to the surface. It was shown that the APDs for porous silicas and organosilicas differ significantly from those obtained for carbonaceous materials, especially in the range of high adsorption potentials which correspond to low relative pressures. Although the high adsorption potential portions of APDs for porous siliceous materials are less informative than those for carbons, they are still useful for monitoring the changes in the surface properties due to the attachment of various organic groups.
Removal of Lead and Cadmium Ions from Aqueous Solution by Polyvinyl Alcohol-Modified Kaolinite Clay: A Novel Nano-Clay Adsorbent
Authors: Unuabonah E.I. , Olu-Owolabi B.I. , Adebowale K.O. , Yang L.Z.
Published: April 2010

Kaolinite clay was modified with polyvinyl alcohol (PVA) to obtain a PVA–nano-clay adsorbent. X-Ray diffraction measurements of the adsorbent showed no observable change in the d-spacing of its crystal lattice. Scanning electron microscopy of the PVA-modified nano-clay adsorbent indicated the presence of irregular crystal structures. Infrared spectroscopy suggested that the PVA–nano-clay adsorbent basically possessed outer –OH functional groups. This adsorbent was found to have an adsorption capacity of 56.18 mg/g for Pb2+ ions and 41.67 mg/g for Cd2+ ions. The adsorption data obtained was well explained by the Diffuse Layer Model (DLM), which implies that the adsorption of both metal ions onto the modified adsorbent was via an inner-sphere surface complexation mechanism. The ΔH0 values for the adsorption of both metal ions onto the PVA–nano-clay were −12.48 kJ/mol for Pb2+ ions and −13.49 kJ/mol for Cd2+ ions, with both ions exhibiting negative adsorption entropies. Data-fitting indicated that both the PVA–nano-clay and the unmodified adsorbent possessed homogeneous and heterogeneous adsorption sites. Virtually complete desorption (ca. 99%) of both metal ions occurred from PVA–nano-clay within 3 min.
Optimizing the Utilization of Natural Gas Condensate through the Separation of n-Paraffins
Authors: Liu Ji-Chang , Shen Ben-Xian , Sun Hui , Dong Ji-Hong
Published: April 2010

To improve the utilization efficiency of gas condensate and effect the proper use of the hydrocarbon components, AKS gas condensate was separated, through the use of a fixed-bed adsorption process employing 5A molecular sieves, into the raffinate oil which is rich in non-normal hydrocarbons and the desorption oil which is rich in n-paraffins. The adsorption breakthrough curves of n-paraffins were investigated. Relative to the gas condensate, the aromatic potential content and the research octane number (RON) of the raffinate oil increased by 12.9% and by over 20 units, respectively. As a result, the raffinate oil is more suitable for use as the feedstock in the catalytic reforming process and as the blending component of high-octane gasoline. Under similar conditions, the ethylene yield of the steam cracking process using the desorption oil as the feedstock increased by 6.5% compared to the situation when the gas condensate was employed as the feedstock.
Wind Integration Cost Impact Study for the Arizona Public Service Company: Modeling Approach and Results
Authors: Acker Thomas L. , Zavadil Robert , Potter Cameron , Flood Ronald
Published: April 2010

The objectives of this study were to analyze operating impacts and costs of integrating wind energy in the Arizona Public Service (APS) balancing area, due to the variability and uncertainty of wind energy. Wind energy penetration levels from 1% to 10% were considered, corresponding to wind power levels of 100 MW to 1400 MW. A production cost simulation was conducted using APS system modeling software to assess the costs, by comparing the total production cost of the system with wind energy with a reference case that excludes the variability and uncertainty of wind energy. For APS's system, with an anticipated peak load of 7,905 MW in 2010, the integration costs were $0.91, $3.25, $3.57, and $4.08 per MWh for 1%, 4%, 7% and 10% wind energy. The geographic diversity of locating wind power plants over a large area was considered and found to have an important influence on the total integration cost.
Uncertainties in Assessing Global Warming during the 20th Century: Disagreement between Key Data Sources
Authors: Ogurtsov Maxim , Lindholm Markus
Published: April 2010

We have reanalyzed the available data on the terrestrial temperature in the Northern Hemisphere over the past 1000 years using both direct observations and various proxy records. It is shown that the only plausible conclusion, which can be drawn from these data is that global temperature has been increasing since the end of the 19th century. However, due to discrepancies between different large-scale temperature proxies, it is impossible to determine whether this warming is anomalous or a result of natural climatic cycles. Furthermore, the amplitude of the temperature rise cannot be estimated correctly because of considerable disagreement between thermometer records, proxy data and satellite measurements over the last 20–30 years. Thus, the origin of the rise of global temperature should be considered to be unknown due to a lack of adequate knowledge about any of the factors that may be responsible for this phenomenon (the greenhouse effect, the rise of solar activity, natural climatic variability, regional anthropogenic impact etc.). A few probable scenarios of climatic changes in the first part of the 21st century are discussed.
Is Stern Review on Climate Change Alarmist?
Authors: Seo S. Niggol
Published: April 2010

This paper is concerned with the conclusion of the Stern Review that the cost of climate change could be as much as 20% of the global GDP. In this paper, I identify two major sources of variation in the estimates of the aggregate cost of climate change. One is the disagreement among the AOGCM models on the magnitude of climate change, and the other is the divergence among the economic models on how harmful these changes will be to the economy. The main conclusion of this paper is that only under the alarmist approach—which assumes both the most severe climate change and the most extreme estimate of climate change damage to the economy—we can be convinced that the cost of climate change is close to 20% of the global GDP in 2100. In most other cases, the cost will be under 1% of the global GDP.
Time-Domain Acoustic Wave Solutions in Sheared Mean Flows
Authors: Zheng Shi , Zhuang Mei
Published: April 2010

The instability waves triggered by an acoustic source of certain frequencies always co-exist with the acoustic waves in the solution of non-homogenous linearized Euler equations (LEE), termed as the total solution, for a given sheared mean flow. The total solution thus contains both the acoustic wave solution and the instability wave solution, the latter referred to as the contained instability wave solution. A time-domain method for obtaining only the acoustic wave solution in sheared mean flows is proposed and verified in this paper. Instead of suppressing or filtering-out the contained instability waves, in the proposed method the acoustic wave solution is achieved by means of subtracting the contained instability wave solution from the total solution of the non-homogenous LEE. The two important aspects of the proposed method are the identification of an appropriate reference point where the instability wave dominates the acoustic wave solution and the development of the approximately pure instability wave solution. The method is feasible to a multi-frequency or broadband sound source and is applicable to mean flows with more relaxed constraints than parallel or slowly varying mean flows. The implementation and effectiveness of the method are demonstrated by solving a test problem of a multi-frequency acoustic source embedded in a sheared mean flow. The acoustic wave solution obtained from the method is verified by the analytical solution.
A Fourier Pseudospectral Method for Some Computational Aeroacoustics Problems
Authors: Huang Xun , Zhang Xin
Published: April 2010

A Fourier pseudospectral time-domain method is applied to wave propagation problems pertinent to computational aeroacoustics. The original algorithm of the Fourier pseudospectral time-domain method works for periodical problems without the interaction with physical boundaries. In this paper we develop a slip wall boundary condition, combined with buffer zone technique to solve some non-periodical problems. For a linear sound propagation problem whose governing equations could be transferred to ordinary differential equations in pseudospectral space, a new algorithm only requiring time stepping is developed and tested. For other wave propagation problems, the original algorithm has to be employed, and the developed slip wall boundary condition still works. The accuracy of the presented numerical algorithm is validated by benchmark problems, and the efficiency is assessed by comparing with high-order finite difference methods. It is indicated that the Fourier pseudospectral time-domain method, time stepping method, slip wall and absorbing boundary conditions combine together to form a fully-fledged computational algorithm.
Glimpses of Aeroacoustic Activities in India
Authors: Munjal M. L. , Ramamurthi K.
Published: April 2010

With contributions from P. Jeyajothiraj, K. L. Handoo, P. R. Murali, (VSSC, Trivandrum), K. Jagadisan (DRDO), P. Surendran (FCRI, Palghat), Ranjan Moodithaya, S. V. Narasimhan (NAL, Bangalore), T. S. Sheshadri, P. J. Paul (IISc, Bangalore,), K. Ashirvadham, S. Nirmal Shankar, V. Shankar (GTRE, Bangalore), D. Das, A. Kushari (IIT Kanpur), K. Srinivasan, T. Sundararajan, S. R. Chakravarthy, R. I. Sujith (IIT Madras) and S. Shankaran (SDSC Shriharikota).
On Evolution and Acoustic Characteristics of a Compressible Vortex Ring
Authors: Murugan Thangadurai , Das Debopam
Published: April 2010

Sound generated during formation of a compressible vortex ring at the open end of a shock tube and during its propagation is studied experimentally for shock Mach numbers of 1.28 to 1.61. The occurrence of different events such as primary ring formation, growth of the primary ring, secondary and tertiary vortices formation, and pinching-off are identified as predominant noise producing events. Wavelet analysis of the measured microphone signal identifies the time of occurrence of the above events which is verified using flow visualization pictures. The distributions of acoustic fluctuations are measured at a fixed distance from the exit center of the tube at different angular locations in horizontal diametrical plane and the directivity of the amplitude of sound pressures associated with the evolution of vortex ring is found. It is observed that the vortex ring's evolution sound is dominant between 25° to 50° angle from the axis of the shock tube. Experiments with short driver section produce rings with small trailing jet. Sound generated during the initial formation of these rings, after the diffraction of the incident shock at the open end of the shock tube, is dominant than the vortex ring's evolution sound. In shock tubes with larger driver section, the primary vortex ring is followed by a relatively longer trailing jet. In these cases, sound generated during formation of subsequent shear-layer vortices and their interaction with the trailing jet is also significant.