bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling and analysis of an ionic polymer-metal composite (IPMC)-rocker-based four-bar for variable path generation using the Euler—Bernoulli approach
Authors: Bandopadhya D , Njuguna J
Published: June 2009

This article evaluates the dynamic performance of a partially compliant four-bar mechanism having an ionic polymer-metal composite (IPMC)-based rocker. The rigid link rocker is replaced with an IPMC actuator for variable path generation. The study aims to address the size limitations of a traditional variable length rigid link rocker, which is actuated by an electric motor for miniature micro-scale applications. Dynamic modelling is carried out taking into account the bending property of the IPMC and Grashof criterion. Simulations are also performed based on the effective length of IPMC following the Euler—Bernoulli approach with input voltage. The investigation demonstrates that by controlling the bending of IPMC along with the rotation of crank, a definite work volume can be generated at the rocker tip.
Free vibration of shallow shells using the Rayleigh—Ritz method and penalty parameters
Authors: Monterrubio L E
Published: June 2009

In the present work, the Rayleigh—Ritz method (RRM) and the penalty function method (PFM) are used to solve vibration problems of shallow shells of rectangular planform with spherical, cylindrical, and hyperbolic paraboloidal geometries with classical boundary conditions. Problems with more complicated constraints can also be solved using the method presented in this work, which consists in developing the stiffness and mass matrices of a completely free shallow shell using the RRM and then all constraints of the shell are defined by the PFM through the use of either artificial stiffness or artificial inertia with either positive or negative values.
The effect of convex wall curvature on the structure of the turbulent boundary layer
Authors: Khoshnevis A B , Hariri S , Farzaneh-Gord M
Published: June 2009

Effects of convex wall curvature on turbulent boundary layer flow are studied in this article using a numerical method. Since the non-linear k−ε model often used in engineering applications cannot satisfy the distribution and wall-limiting behaviour of the Reynolds stress components, an improved low Reynolds number k−ε turbulence model has been employed to model turbulences in this study. Based on numerical solutions, turbulent intensity, turbulent shear stress, and mean velocity are calculated. The results show that the turbulent intensities and turbulent shear stresses are decreased on convex walls compared with flat plates under similar conditions. The numerical results also show that for the boundary layer on convex surfaces, the stabilizing effects lead to less turbulent momentum exchange between fluid particles. The rate of integral parameters of the boundary layer such as momentum thickness and displacement thickness is reduced on convex curvature compared to their values on the flat plate. To validate the numerical method, the numerical results have been compared with previous measured values and good agreement has been obtained.
Screw replacements in isomeric variants of Bricard's line-symmetric six-bar
Authors: Baker J E
Published: June 2009

Much has been achieved over the past 40 years in searching for solutions to overconstrained, single-loop linkages of mobility 1, including the complete resolution of four-bar kinematic chains. In the cases of five- and six-bar linkages, however, analytical approaches are so confronting that some form of synthesis has often proved to be fruitful. The present exploration employs one such technique to isolate three previously unknown six-revolute loops, together with a determination of their displacement—closure relationships. Integral to the work is an examination of the extent to which the turning pairs might be replaced by screws. As well, the opportunity is taken to duly modify the existing record of six-revolute linkages.
Reducing the drag on a circular cylinder by upstream installation of an I-type bluff body as passive control
Authors: Triyogi Y , Suprayogi D , Spirda E
Published: June 2009

The bluff body cut from a small circular cylinder that is cut at both sides parallel to the y-axis was used as passive control to reduce the drag of a larger circular cylinder. The small bluff body cut is called an I-type bluff body, which interacts with a larger one downstream. I-type bluff bodies with different cutting angles of θs = 0°(circular), 10°, 20°, 30°, 45°, 53°, and 65° were located in front and at the line axis of the circular cylinder at a spacing S/ d = 1.375, where their cutting surfaces are perpendicular to the free stream velocity vector. The tandem arrangement was tested in a subsonic wind tunnel at a Reynolds number (based on the diameter d of the circular cylinder and free stream velocity) of Re = 5.3×104. The results show that installing the bluff bodies (circular or sliced) as a passive control in front of the large circular cylinder effectively reduces the drag of the large cylinder. The passive control with cutting angle θs = 65° gives the highest drag reduction on the large circular cylinder situated downstream. It gives about 0.52 times the drag of a single cylinder.
The effect of ring baffles on the hydrodynamics of a gas—solid bubbling fluidized bed using computational fluid dynamics
Authors: Hosseini S H , Rahimi R , Zivdar M , Samimi A
Published: June 2009

An Eulerian—Eulerian two-fluid model (TFM) integrating the kinetic theory for emulsion phase was used to simulate gas—solid fluidized beds. Validation of the model was investigated based on hydrodynamic parameters such as bed expansion ratio, H/ H0, gas volume fraction profile, bubble behaviour, and motion of the particles. A good agreement was found between numerical results and experimental values. The model was used to study a bubbling fluidized bed (BFB) including the ring baffles. Predicted results show that the ring baffles have an important role in the flow pattern of the bed. Baffles increase the bed expansion height and particle velocities at axial locations on the top of the highest baffle as well as uniform distribution of gas volume fraction between the baffles area. In spite of increasing the dead zones in the bed, ring baffles cause the improvement of mixing and heat transfer in the bed. The present study provides a useful basis for further works on the effect of baffles in BFBs.
An integrated qualitative trend analysis approach to identify process abnormalities: A case of oil export pumps in an offshore oil and gas production facility
Authors: Raza J , Liyanage J P
Published: June 2009

Oil and gas production can be largely benefited by minimizing unwanted production losses. This can be done by effective identification of system anomalies and faults. In standard control systems these abnormalities can be observed as gradually deviating trends from the norms. Available tools for monitoring these trends, in some cases, may not be enough to reveal hidden faulty features. In order to interpret these changes accurately, measured data must be visualized as a combination of multiple sensor signals within a particular domain. This article suggests an approach to effectively utilize integrated data from multiple sources, and defines a set of 12 fault features. The approach, in principle, encodes real plant data in the form of logical IF-THEN rules in Microsoft Excel. Confidence values are set based on these interpretations to differentiate between normal and abnormal conditions exhibited by the system. This is to provide an opportunity for the process and maintenance engineers to effectively identify the equipment's health based on the early identification of developing abnormalities.
Gasketed bolted flange joint's relaxation behaviour under different bolt up strategy
Authors: Khan K A , Abid M , Chattha J A
Published: June 2009

Performance of a bolted flange joint is characterized mainly by its ‘strength’ and ‘sealing capability’. Sealing capability of a bolted flange joint is highly dependent on the bolt up strategy during assembly because gasket stress distribution achieved during assembly process is the prime parameter. Any improper bolt up practice may result in the leakage from the joint. In this article, two different bolt up strategies used in the industries during the assembly of a bolted flanged joint are used and joints relaxation, gasket stress variation, and joint's strength are analysed using detailed non-linear finite-element analysis.
A new method to deduce the stress in a catenary support structure based on novel hybrid simulation
Authors: Weihua Z , Ning Z , Bingrong M
Published: June 2009

Based on a stress investigation of structural failures of the railway system in China, a new method to determine the stress is put forward to overcome the deficiency of conventional simulation and experiment methods. Through numerical simulation, the inference relation of the stress between various locations is obtained. Then, by experiment, some stresses in the whole structure are measured. Accordingly, other stresses are determined through the inference relation. Furthermore, all the stresses in the structure are obtained and the strength evaluation can be exactly carried out. Taking the cantilever beam and the cantilever device supporting the catenary for example, how to deduce the stress by this method is discussed.
Influences of car body vertical flexibility on ride quality of passenger railway vehicles
Authors: Zhou J , Goodall R , Ren L , Zhang H
Published: June 2009

To study the influences of carbody vertical stiffness on vehicle ride quality, a vertical model of railway passenger vehicles, which includes the carbody flexible effects and all vertical rigid modes, is built. With the model and the covariance method, the requirements for the carbody bending frequency are researched. The results show that when the stiffness of a carbody decreases to certain frequencies there are significant vibrations in the carbody, although structural damping provided by a fully equipped carbody will help attenuate the vibration to some extent. A simple way to avoid resonant vibration is to increase the bending frequencies of a carbody: the higher the vehicle running speed, the higher carbody stiffness could be required. However, there are practical limitations to such an increase and the method used in this study can readily obtain the lowest bending frequency required by vehicle ride quality. Finally, the geometric filtering phenomenon and its influences on the carbody resonant flexural vibration are analysed. Results show that it is this phenomenon rather than the natural vibrations of bogie bounce that most strongly influences the resonant flexural vibration of a railway carbody.
Experimental performance of a compliant scroll expander for an organic Rankine cycle
Authors: Wang H , Peterson R B , Herron T
Published: June 2009

A small-scale scroll expander was developed and tested. The expander was based on a compliant scroll compressor having a displacement of ∼6.8 cm3. A test loop was also developed for determining expander performance parameters. The loop employed a compressor to pressurize the working fluid up to 2758 kPa and a heat exchanger to create the expander inlet conditions that would characterize an operating power cycle. The expander was tested with R134a as the working fluid. For power output measurements, a dynamometer was used where torque and rotational rate were measured. An important feature in adapting a scroll compressor to expander duty was the lubrication of the scroll wraps during operation and the lubrication required by the journal bearings within the expander housing. The approach used in this study was to dissolve a compatible oil into the circulating working fluid to lubricate the wraps, while a pump was employed to deliver pressurized oil to the bearings. The pressurized oil supply was also used to generate a controlled force to the upper stationary scroll wrap through a sealed piston assembly. This force maintained axial contact between the upper and lower scroll wraps during operation. After expansion, the R134a vapour passed through an orifice flow meter and then to a liquid-cooled heat exchanger. It then enters a compressor and heat exchanger to complete the flow loop. A series of performance tests were conducted on the expander at various expander rotational speeds, inlet and outlet pressures, and scroll sealing pressures. Test results show consistent isentropic efficiencies of over 70 per cent for the expander at its maximum efficiency operating points. The expander performance, however, is a function of speed, pressure ratio, and scroll sealing pressure.
Effects of spark-assistance on controlled auto-ignition combustion at different injection timings in a multicylinder direct-injection gasoline engine
Authors: Kalian N , Zhao H , Yang C
Published: June 2009

Controlled auto-ignition (CAI) combustion, also known as homogeneous charge compression ignition (HCCI) can be achieved by trapping residuals with early exhaust valve closure in a direct fuel injection in-cylinder four-stroke gasoline engines. CAI combustion is achieved by auto-ignition independent of spark discharge. However, it is found that, at loads with reduced trapped residuals, the presence of spark influences combustion. Therefore the effects of spark timing on the CAI combustion process were investigated through the introduction of spark. The effect on engine performance and the emission specific values were evaluated. The engine speed was maintained at 1500 r/min and lambda was kept constant at 1.2. It was found that with spark-assisted CAI, indicated mean effective pressure (IMEP), and indicated specific oxides of nitrogen (ISNO x) values increased as compared with CAI without spark. ISHC and ISCO values were lower for spark-assisted CAI as compared with CAI without spark. Heat release data were analysed to better understand this phenomenon.
Patient satisfaction with carpal tunnel surgery: self-administered questionnaires versus physical testing
Authors: Astifidis Romina P , Koczan Barbra J , Dubin Norman H , Burke Frank D , Wilgis E F Shaw
Published: June 2009

Purpose

A study was designed to compare the strength of correlation between the clinical tests such as grip, pinch and Semmes–Weinstein testing, and the Levine–Katz self-administered symptom severity and functional status questionnaires as well as their correlation with patients' satisfaction following carpal tunnel decompression. The purpose was to determine whether patient-completed outcome instruments would be additive to the physical measures, or could possibly replace the physical measures, in assessing the outcome of carpal tunnel release.

Methods

From two hand centres, 635 hands (cases) in 490 patients completed preoperative and postoperative assessments including Tinel's sign, Phalen's test, Semmes–Weinstein testing, grip and pinch strength testing and the Levine–Katz self-administered questionnaires. Patients were also asked whether they were satisfied with surgery at the six-month follow-up.

Results

Patients reporting satisfaction with surgery at six months had significantly greater changes in grip strength and Levine–Katz scores than those reporting no satisfaction. At six-months follow-up, grip strength increased slightly from 27.4 to 29.2 kg (6%) ( P = 0.007), pinch strength increased from 7.8 to 8.1 kg (4%) ( P = 0.04), Semmes–Weinstein scores decreased (improved) from 2.37 to 1.89 (20%) ( P < 0.001), Levine–Katz functional status scores decreased from 2.30 to 1.48 (36%) ( P < 0.001) and Levine–Katz symptom severity scores decreased from 2.83 to 1.44 (49%) ( P < 0.001).

Conclusions

Improvement in Levine–Katz scores can be used to assess treatment outcomes after carpal tunnel release as an alternative to physical testing. This study offers further evidence that patient-rated outcome questionnaires offer a more complete picture of the eventual outcomes of carpal tunnel decompression surgery as compared with physical testing.
Modified PAXgene™ method allows for isolation of high-integrity total RNA from microlitre volumes of mouse whole blood
Authors: Krawiec J A , Chen H , Alom-Ruiz S , Jaye M
Published: June 2009

Analysis of gene expression is often used to evaluate the effects of experimental manipulations in laboratory animals. Blood is a rich source of potential biomarkers, including gene expression information, which may be obtained from whole blood. When compared with the end of a study, when whole blood samples can be easily obtained for gene expression measurements, the limiting volumes of whole blood obtainable from animals during the course of an experiment requires a method for RNA isolation from a minimal volume of whole blood. The PAXgene™ Blood RNA Extraction System originally designed for isolation of total RNA from 2.5 mL of human whole blood, was modified and successfully used to isolate high-integrity total RNA from as little as 50 μL of mouse whole blood. Fifty microlitres of mouse whole blood yielded an average of 2.3 μg highly intact total RNA, of sufficient quality and quantity allowing for multiple gene expression determinations. The utility of this method was demonstrated by confirming the time- and dose-dependent upregulation of haem oxygenase-1 ( Hmox1) mRNA in response to a single injection of cobalt protoporphyrin. The successful isolation of total RNA from small volumes of mouse whole blood can allow for serial sampling on the same animals, thereby reducing the number of animals required for experimentation.
Connectivity Measures for Internet Topologies on the Level of Autonomous Systems
Authors: Erlebach Thomas , Moonen Linda S. , Spieksma Frits C. R. , Vukadinović Danica
Published: June 2009

Classical measures of network connectivity are the number of disjoint paths between a pair of nodes and the size of a minimum cut. For standard graphs, these measures can be computed efficiently using network flow techniques. However, in the Internet on the level of autonomous systems (ASs), referred to as AS-level Internet, routing policies impose restrictions on the paths that traffic can take in the network. These restrictions can be captured by the valley-free path model, which assumes a special directed graph model in which edge types represent relationships between ASs. We consider the adaptation of the classical connectivity measures to the valley-free path model, where it is 𝒩𝒫-hard to compute them. Our first main contribution consists of presenting algorithms for the computation of disjoint paths, and minimum cuts, in the valley-free path model. These algorithms are useful for ASs that want to evaluate different options for selecting upstream providers to improve the robustness of their connection to the Internet. Our second main contribution is an experimental evaluation of our algorithms on four types of directed graph models of the AS-level Internet produced by different inference algorithms. Most importantly, the evaluation shows that our algorithms are able to compute optimal solutions to instances of realistic size of the connectivity problems in the valley-free path model in reasonable time. Furthermore, our experimental results provide information about the characteristics of the directed graph models of the AS-level Internet produced by different inference algorithms. It turns out that (i) we can quantify the difference between the undirected AS-level topology and the directed graph models with respect to fundamental connectivity measures, and (ii) the different inference algorithms yield topologies that are similar with respect to connectivity and are different with respect to the types of paths that exist between pairs of ASs.
Surgical training and incidence of infective complications in elective orthopaedic practice
Authors: Goddard R , Yeoh D , Mowbray M
Published: June 2009

Numerous factors are known to be associated with an increased rate of deep infection in joint arthroplasty. However, most deep infections occurring during total joint arthroplasty result from airborne contaminants shed by the operating personnel. Ultra-clean air sources in orthopaedic theatres and prophylactic antibiotics are thought to reduce the incidence of infection. Other factors such as the use of non-disposable drapes, poor theatre discipline, the method of skin preparation and surgical suction devices are all implicated in the genesis of wound infection. We are not aware of any study that has investigated the impact of training junior orthopaedic surgeons on the incidence of deep wound infection.
Opportunities for randomised surgical trials
Authors: Blazeby Jane M
Published: June 2009

Well-designed and conducted randomised controlled trials (RCTs) generate quality evidence that leads to improvement in surgical practice. The evidence can inform individual decision-making about the benefits and harms of a procedure, underpin national guidelines and influence policy decisions regarding investment. Although the number of surgical RCTs is substantially higher in the UK than in many other European countries, the need for more and better surgical trials is well recognised. In the UK there have recently been several major changes in research funding and infrastructure for clinical trials and these represent an important opportunity for surgeons to collaborate with clinical trials units and methodologists to design and conduct randomised surgical trials.
The Down Syndrome Advantage: Fact or Fiction?
Authors: Corrice April M. , Glidden Laraine Masters
Published: June 2009

The “Down syndrome advantage” is the popular conception that children with Down syndrome are easier to rear than children with other developmental disabilities. We assessed whether mothers of children with developmental disabilities would demonstrate a consistent Down syndrome advantage as their children aged from 12 to 18 years. Results did not reveal significant differences between mothers of children with Down syndrome and mothers of children with other developmental disabilities on most maternal functioning variables. Although the prior group reported a consistent advantage in terms of personal reward and subjective well-being, these diagnostic group differences disappeared when maternal age and child adaptive behavior were controlled. We concluded that these variables may help to explain the Down syndrome advantage.
Functional Skills of Individuals With Fragile X Syndrome: A Lifespan Cross-Sectional Analysis
Authors: Bailey Donald B. , Raspa Melissa , Holiday David , Bishop Ellen , Olmsted Murrey
Published: June 2009

Parents of 1,105 male and 283 female children with fragile X syndrome described functional skill attainment in eating, dressing, toileting, bathing/hygiene, communication, articulation, and reading. The majority of adult children had mastered many skills independently. Most adults were verbal, used the toilet, dressed, ate independently, bathed, and used a towel independently. However, some skills were not as well-developed, such as using complex sentences, reading, or speaking at a typical rate. As expected, significant differences were found between males and females. The findings highlight major skill attainments, identify skills that should be the target of specific intervention programs, suggest variable trajectories to be tested more precisely through direct assessments and longitudinally, and provide baseline data for treatment studies.
Coiling characteristics of umbilical cords in breech vs. vertex presentation
Authors: Ochshorn Yifat , Bibi Guy , Ascher-Landsberg Jessica , Kupferminc Michael J. , Lessing Joseph B. , Many Ariel
Published: June 2009

Objective:To compare selected umbilical cord parameters, especially cord coiling, between breech and vertex presentations.

Methods:We prospectively collected umbilical cords from uncomplicated breech and vertex obtained during elective term cesarean deliveries. We compared various cord parameters between the two groups as well as data regarding obstetric history and pregnancy outcome.

Results:We evaluated 55 umbilical cords from breech and 55 from vertex deliveries. Umbilical cord length (56.93 cm vs. 63.95 cm, P=0.05), number of coils (5.1±0.4 vs. 11.7±0.6, P<0.0001) and umbilical cord index (UCI) (0.09 coils/cm vs. 0.18 coils/cm, P<0.0001) were all significantly lower for breech presentations and remained significant following multivariate analysis.

Conclusion:We document significant differences in umbilical coiling and the UCI between breech and vertex presentation. The precise reason for these differences is still unclear.
Cleopatra′s Snake or Octavian′s? The Role of the Cobra in the triumph over the Egyptian Queen
Authors: Kostuch Lucyna
Published: June 2009

The snake′s familiar erotic connotation, consolidated in various interpretations, tends to limit consideration of the multifaceted capacity of this symbol as a carrier of specific content, which depending on the context, may be used in various meanings. Academic discussion on the symbolic meaning of the snake in Cleopatra′s act of suicide generally confines itself only to the Egyptian perspective or, more broadly, to that of the east (the uraeus, Isis, Bacchic elements), without considering the Roman space of military symbolism. The validity of reinterpreting the snake symbol in this specific situation is supported both by the fact that an image of Cleopatra with snake on display was carried in the triumphal procession, and by Octavian′s own association with it, which ascribes a military character to the reptile and provides reasons for the propaganda use of that symbol.
The Significance of Roman Imperial Coin Types
Authors: Beckmann Martin
Published: June 2009

Did Roman Imperial coin types have significant news or propaganda content, or were they generic? This article (focussing on the coinage of Trajan) argues that this depends on what part of the coinage is considered. The gold and bronze coins had substantial news content, but the silver coinage generally did not. This situation arose because two factors, sometimes conflicting, governed the choice of coin types in Trajan′s mint: first, the desire to select topical images; second, the need to maintain uninterrupted the mass-production of coins. As a result, the lower-volume portions of the coinage were adorned with more up-to-date types, and these were changed often; the higher-volume coinage on the other hand – especially the silver denarii – tended to employ generic and outdated types.
Against the Clock: Slumdog Millionaire and The Curious Case of Benjamin Button
Authors: Tyree J. M.
Published: June 2009

A comparison of two award-winning cinematic romances in terms of their diverging treatments of love and time: whereas Slumdog Millionaire moves toward a happy ending, The Curious Case of Benjamin Button is more melancholy.
Effect of DHEA and metformin on corpus luteum in mice
Authors: Sander Valeria A , Facorro Graciela B , Piehl Lidia , Rubín de Celis Emilio , Motta Alicia B
Published: June 2009

We evaluated the effect of hyperandrogenism in ovaries with functional and regressing corpora lutea (CL) and the action of metformin in preventing these possible alterations using a mouse model. To obtain a CL functional for 9±1 days, immature female mice of the BALB/c strain were injected i.p. with 10 IU/mouse of pregnant mare's serum gonadotropin (PMSG). DHEA (60 mg/kg body weight s.c., 24 and 48 h prior to kill) decreased both serum progesterone (P) and estradiol (E2) levels and increased the activity of superoxide dismutase (SOD) from ovaries with functional CL (on day 5 after PMSG). It increased P and E2and the activities of SOD and catalase (CAT) and decreased lipoperoxidation of ovaries with regressing CL (on day 9 after PMSG). Treatment with DHEA did not affect the production of prostaglandin F2α(PGF2α) or PGE by ovaries with functional CL, whereas DHEA decreased PGF2αand increased PGE production by ovaries with regressing CL. Metformin (50 mg/kg body weight, orally) given together with DHEA restored E2levels from mice with ovaries with functional CL and serum P, PGF2αand PGE levels, and oxidative balance in mice with ovaries with regressing CL. Metformin alone was able to modulate serum P and E2levels, lipoperoxidation, SOD and CAT, and the 5,5-dimethyl-1-pyrrolineN-oxide/•OH signal. These findings suggest that hyperandrogenism is able to induce or to rescue CL from luteolysis and metformin treatment is able to prevent these effects.
Maximal expression of suppressors of cytokine signaling in the rat ovary occurs in late pregnancy
Authors: Anderson Stephen T , Isa Naajia N M , Barclay Johanna L , Waters Michael J , Curlewis Jon D
Published: June 2009

Maintenance of the rodent corpus luteum (CL) during pregnancy requires prolactin receptor (PRLR) signal transduction via STAT5. At the end of pregnancy, prostaglandin F2α (PGF2α) induces luteal regression through many mechanisms, including downregulation of PRLR signaling. We have previously shown that a PGF2α analog upregulates suppressors of cytokine signaling (SOCS) proteins in the CL of day 19 pregnant rats leading to reduced STAT5 signaling. Here, we examined endogenous SOCS expression and STAT5 signaling in the rat ovary during normal pregnancy and luteolysis. The mRNA expression of Socs1, Socs2, and Socs3 and related cytokine-inducible SH2-containing protein (Cish) was low in early pregnancy (day 7), but significantly increased at mid-pregnancy (days 10 and 13) associated with increased endogenous tyrosine phosphorylation (TyrP) of STAT5. In support of the notion that these changes are due to increasing placental lactogen levels at this time, we found that treatment with exogenous PRL on day 7 increased TyrP of STAT5 and induced SOCS mRNA expression, except Socs3. After mid-pregnancy, further significant increases in Socs3 and Cish mRNA expression were observed. Such changes in mRNA expression correlated with protein levels, with protein levels of both SOCS3 and CISH being maximal in late pregnancy (days 19–21). In addition, a significant reduction in TyrP of STAT5 was first observed on day 20, with a further substantial decrease on day 21. Therefore, these results are consistent with the hypothesis that increased SOCS expression in the rat ovary during late pregnancy reduces STAT5 signaling, which may be important in PGF2α-induced luteolysis.
Influence of birth weight on gene regulators of lipid metabolism and utilization in subcutaneous adipose tissue and skeletal muscle of neonatal pigs
Authors: Williams P J , Marten N , Wilson V , Litten-Brown J C , Corson A M , Clarke L , Symonds M E , Mostyn A
Published: June 2009

Epidemiological studies suggest that low-birth weight infants show poor neonatal growth and increased susceptibility to metabolic syndrome, in particular, obesity and diabetes. Adipose tissue development is regulated by many genes, including members of the peroxisome proliferator-activated receptor (PPAR) and the fatty acid-binding protein (FABP) families. The aim of this study was to determine the influence of birth weight on key adipose and skeletal muscle tissue regulating genes. Piglets from 11 litters were ranked according to birth weight and 3 from each litter assigned to small, normal, or large-birth weight groups. Tissue samples were collected on day 7 or 14. Plasma metabolite concentrations and the expression ofPPARG2,PPARA,FABP3, andFABP4genes were determined in subcutaneous adipose tissue and skeletal muscle. Adipocyte number and area were determined histologically. Expression ofFABP3and4was significantly reduced in small and large, compared with normal, piglets in adipose tissue on day 7 and in skeletal muscle on day 14. On day 7,PPARAandPPARG2were significantly reduced in adipose tissue from small and large piglets. Adipose tissue from small piglets contained more adipocytes than normal or large piglets. Birth weight had no effect on adipose tissue and skeletal muscle lipid content. Low-birth weight is associated with tissue-specific and time-dependent effects on lipid-regulating genes as well as morphological changes in adipose tissue. It remains to be seen whether these developmental changes alter an individual's susceptibility to metabolic syndrome.
Evidence that single-stranded DNA breaks are a normal feature of koala sperm chromatin, while double-stranded DNA breaks are indicative of DNA damage
Authors: Zee Yeng Peng , López-Fernández Carmen , Arroyo F , Johnston Stephen D , Holt William V , Gosalvez Jaime
Published: June 2009

In this study, we have used single and double comet assays to differentiate between single- and double-stranded DNA damage in an effort to refine the interpretation of DNA damage in mature koala spermatozoa. We have also investigated the likelihood that single-stranded DNA breakage is part of the natural spermiogenic process in koalas, where its function would be the generation of structural bends in the DNA molecule so that appropriate packaging and compaction can occur. Koala spermatozoa were examined using the sperm chromatin dispersion test (SCDt) and comet assays to investigate non-orthodox double-stranded DNA. Comet assays were conducted under 1) neutral conditions; and 2) neutral followed by alkaline conditions (double comet assay); the latter technique enabled simultaneous visualisation of both single-stranded and double-stranded DNA breaks. Following the SCDt, there was a continuum of nuclear morphotypes, ranging from no apparent DNA fragmentation to those with highly dispersed and degraded chromatin. Dispersion morphotypes were mirrored by a similar diversity of comet morphologies that could be further differentiated using the double comet assay. The majority of koala spermatozoa had nuclei with DNA abasic-like residues that produced single-tailed comets following the double comet assay. The ubiquity of these residues suggests that constitutive alkali-labile sites are part of the structural configuration of the koala sperm nucleus. Spermatozoa with ‘true’ DNA fragmentation exhibited a continuum of comet morphologies, ranging from a more severe form of alkaline-susceptible DNA with a diffuse single tail to nuclei that exhibited both single- and double-stranded breaks with two comet tails.
A modified culture method significantly improves the development of mouse somatic cell nuclear transfer embryos
Authors: Dai Xiangpeng , Hao Jie , Zhou Qi
Published: June 2009

Many strategies have been established to improve the efficiency of somatic cell nuclear transfer (SCNT), but relatively few focused on improving culture conditions. The effect of different culture media on preimplantation development of mouse nuclear transfer embryos was investigated. A modified sequential media method, named D media (M16/KSOM and CZB-EG/KSOM), was successfully established that significantly improves SCNT embryo development. Our result demonstrated that while lacking any adverse effect onin vivofertilized embryos, the D media dramatically improves the blastocyst development of SCNT embryos compared with other commonly used media, including KSOM, M16, CZB, and αMEM. Specifically, the rate of blastocyst formation was 62.3% for D1 (M16/KSOM) versus 10–30% for the other media. An analysis of media components indicated that removing EDTA and glutamine from the media can be beneficial for early SCNT embryo development. Our results suggest thatin vitroculture environment plays an important role in somatic cell reprogramming, and D media represent the most efficient culture method reported to date to support mouse SCNT early embryo developmentin vitro.
The extracellular calcium-sensing receptor is expressed in the cumulus–oocyte complex in mammals and modulates oocyte meiotic maturation
Authors: De Santis Teresa , Casavola Valeria , Reshkin Stephan Joel , Guerra Lorenzo , Ambruosi Barbara , Fiandanese Nadia , Dalbies-Tran Rozenn , Goudet Ghylene , Dell'Aquila Maria Elena
Published: June 2009

The extracellular calcium-sensing receptor (CASR) plays an important role in cells involved in calcium (Ca2+) homeostasis by directly sensing changes in the extracellular Ca2+ion concentration. We previously reported the localization and quantitative expression of CASR protein in human oocytes. In this study, we examined the expression and the functional role of CASR during oocyte meiotic maturation in a large mammal animal model, the horse. As in humans, CASR protein was found to be expressed in equine oocytes and cumulus cells. Western-blot analysis revealed a single 130 kDa band in denuded oocytes and a doublet of 130–120 kDa in cumulus cells. CASR labeling was observed by confocal microscopy in cumulus cells and in oocytes on the plasma membrane and within the cytoplasm at all examined stages of meiosis. Functionally, the CASR allosteric effector NPS R-467, in the presence of 2.92 mM external Ca2+, increased oocyte maturation rate in a dose-dependent manner and its stimulatory effect was attenuated by pre-treatment with the CASR antagonist NPS 2390. NPS R-467 had no effect in suboptimal external Ca2+(0.5 mM), indicating that it requires higher external Ca2+to promote oocyte maturation. In oocytes treated with NPS R-467, CASR staining increased at the plasmalemma and was reduced in the cytosol. Moreover, NPS R-467 increased the activity of MAPK, also called ERK, in cumulus cells and oocytes. These results provide evidence of a novel signal transduction pathway modulating oocyte meiotic maturation in mammals in addition to the well-known systemic hormones.
Hypermethylation of the IGF2 differentially methylated region 2 is a specific event in insulinomas leading to loss-of-imprinting and overexpression
Authors: Dejeux Emelyne , Olaso Robert , Dousset Bertrand , Audebourg Anne , Gut Ivo G , Terris Benoit , Tost Jörg
Published: June 2009

Prediction of the evolution of endocrine pancreatic tumors remains difficult based on histological criteria alone. We have previously demonstrated that epigenetic changes are an early event in a mouse model developing insulinomas. Particularly, overexpression of the imprinted IGF2 was caused by the hypermethylation of CpGs in the differentially methylated region 2 (DMR2). Here, we investigated whether IGF2 hypermethylation is also observed in human insulinomas and whether this alteration is common to other human endocrine tumors of the pancreas and the digestive tract. We analyzed the methylation status of 40 CpGs located in the DMR0 and DMR2 of the IGF2 as well as in the H19 DMR by pyrosequencing in a cohort of 62 patients with pancreatic or small intestine endocrine tumors. Altered methylation patterns were observed in all tumor types for the different regions of IGF2, but not for H19. However, hypermethylation of the IGF2 DMR2 was specific for insulinomas and did not occur in any of the other types of tumors which were characterized by a loss of methylation in this region. Gain of methylation in the IGF2 DMR2 in insulinomas correlated with loss-of-imprinting and promoter 4 mediated overexpression of IGF2 at the RNA and protein level. Furthermore, a decreasing degree of methylation in the different regions of IGF2 correlated well with increasing degree of malignancy according to the WHO classification of pancreatic endocrine tumors (PETs), suggesting that methylation of IGF2 might be a useful biomarker for classification and staging of PETs.
Circulating angiopoietin-2 is elevated in patients with neuroendocrine tumours and correlates with disease burden and prognosis
Authors: Srirajaskanthan R , Dancey G , Hackshaw A , Luong T , Caplin M E , Meyer T
Published: June 2009

Angiogenesis is an essential process in the development and growth of tumours. There are a large number of angiogenic mediators including the angiopoietin (Ang) family and vascular endothelial growth factor, which play an important role in both physiological and pathological angiogenesis. This study examines serum levels of Ang-1 and Ang-2 in patients with neuroendocrine tumour (NET) compared healthy controls. ELISA for Ang-1 and Ang-2 was performed in 47 patients with histologically proven NETs and 44 healthy controls. Immunohistochemical staining for Ang-2 was performed in patients to demonstrate cellular location of Ang-2. Serum Ang-2 levels were significantly elevated in patients compared controls (median 4756 vs 2495 pg/ml, P<0.001), while there was no significant difference in Ang-1 levels. The ratio of Ang-2:Ang-1 was significantly elevated in patients compared controls (0.13 vs 0.066, P<0.001). Serum Ang-2 levels were significantly elevated in patients with distant metastases compared with those without metastasis (median 5080 vs 3360 pg/ml, P=0.01). There was also a significant increase between Ang-2 levels and volume of liver metastases (P=0.014). Time to disease progression was worse in patients with serum Ang-2 levels >4756 pg/ml (P=0.04). Serum Ang-2 but not Ang-1 is elevated in NET patients. Ang-2 may be a useful serum marker for monitoring and assessment of prognosis in patients with NETs.
Use of Electronic Computers in Maintaining Production and Engineering Records
Authors: Guthrie R.K.
Published: June 2009

Introduction

At the Fifth Oil Recovery conference held At the A & M College of Texas during December, 1952, we outlined a plan which, when completed, would result in the mechanization of not only many petroleum engineering calculations, but most of the routine and clerical work associated with processing petroleum engineering data.

The material presented herein represents six years progress in our thinking on how mechanization can best be fitted to such work.

Fitting the Maintenance of Production and Engineering Records Into a Producing Department Organization

Before a mechanization program of any magnitude is undertaken, it should first be determined just how record keeping and data handling fit into the overall organization of the production department and how it is linked with other departments of the company. Many of the requirements for production and engineering information from various departments within a company are similar enough that a mechanized system can be designed which will serve them all. In as much as mechanization and the planning for mechanization are expensive, an overall review should first be made to prevent unnecessary duplication.

Figure 1is a simplified diagram showing information now and supervisory control channels in the producing department of a typical company organized with Field, Division, and Headquarters offices. The three items of data shown as being collected are those which contribute the bulk of the data processing problems in the producing department of a company, namely, production (oil, gas, water), well test, and well status information.

Outlining the Record-Keeping Processing Currently Used

The next step in a mechanization program is to make a survey of the processing system currently used. How is the record-keeping ordinarily accomplished? One is always startled at the maze of paper work involved in recording and transcribing the major items such as production, tests, and well status.
Analyses of Wellbore Instability in Drilling Through Chemically Active Fractured-Rock Formations
Authors: Nguyen Vinh X. , Abousleiman Younane N. , Hoang Son K.
Published: June 2009

Numerous time-dependent wellbore-instability problems have been reported while drilling through the chemically active fractured-shale formations in the Arabian Gulf. Very often, these shales are characterized by the abundance of not only macroscale bedding planes but also networks of microscale natural fractures. The presence of fractures weakens the shale mechanically and produces higher-permeability fluid-flow paths within the low-permeability rock formation. Because of different fluid-diffusion rates between the fractures and shale matrix, there are two distinct pore-pressure fields in saturated fractured shale. Additionally, in chemically active shale formations, osmotic pressure arises because of the imbalance in mud/shale chemical activity. Practically, it is extremely complex to isolate the fractures from the matrix for analysis or to identify fracture size and fracture density. However, a first-order approach in an attempt to understand the porous fractured-shale behavior is to use dual-porosity and dual-permeability theory of poromechanics in the analytical modeling. In this study, a poromechanical inclined-wellbore solution has been derived that incorporates time dependency, a primary porosity and permeability for the matrix, a secondary porosity and permeability for the fractures, and the chemical effect. The expressions for the stresses and pressure solutions are presented and detailed in Appendix A. These analytical solutions are used to simulate an inclined-wellbore-stability problem in a fractured-shale formation, accounting also for bedding planes in some instances in addition to the microfractures. Additionally, retrieved rock samples of fractured shale were tested by use of an innovative laboratory characterization device, the Inclined Direct Shear Testing Device (IDSTD) (PoroMechanics Institute; Norman, Oklahoma; 2008). This device tests tiny shale specimens (rock volume less than 0.14 in.3) and is capable of measuring cohesion and friction angle while the sample is subjected to in-situ stresses, varying mud pressures, and mud-circulation times.
A General Unstructured-Grid, Equation-of-State-Based, Fully Implicit Thermal Simulator for Complex Reservoir Processes
Authors: Liu K. , Subramanian G. , Dratler D. I. , Lebel J. P. , Yerian J. A.
Published: June 2009

This paper describes a general unstructured-grid, equation-ofstate-(EOS) based, fully implicit thermal simulator for complex reservoir processes. Under the unstructured grid framework, the simulator uses Newton's method to solve component material-balance equations, energy-balance equation, and volume-balance equation for component moles, energy, and pressure, where chemical reactions and external heat sources/sinks are treated in source terms. Because of the similarity among component material-balance equations and the energy-balance equation, energy is treated as a "component" to achieve a uniform formulation with common code for all simulations (black-oil, compositional, and thermal).

The thermal simulator was validated using analytical models and other thermal simulators. The thermal simulator is used to study grid-orientation problems and to design and optimize Cold Lake heavy-oil development.
Inevitable Disappointment in Projects Selected on the Basis of Forecasts
Authors: Chen M. , Dyer J.
Published: June 2009

Investors often select projects whose estimated performance measures meet or exceed a hurdle value. At the time of decision making, the true performance of a project is unknown but uncertain forecasts are available. Decision makers (DMs) often ignore the prediction errors when they use these forecasts to choose projects. To the disappointment of the DMs, many selected projects result in smaller actual yields than those that were forecasted.

Some have attributed the cause of this to the optimistic bias of the predictions. This paper shows that this disappointment can occur even if the prediction is unbiased. In this case, a bias can be introduced by the selection process that will allow more unattractive (overestimated) projects to be accepted than attractive (underestimated) ones. Although a similar phenomenon has been noted in statistics and finance research, it is not well understood in the context of project selection by DMs.

We present a solution method based on Bayesian updating and demonstrate its effectiveness in eliminating the disappointment in project selection with realistic data from oil exploration and production projects.